NAME¶
guestfs - Library for accessing and modifying virtual machine images
SYNOPSIS¶
#include <guestfs.h>
guestfs_h *g = guestfs_create ();
guestfs_add_drive (g, "guest.img");
guestfs_launch (g);
guestfs_mount (g, "/dev/sda1", "/");
guestfs_touch (g, "/hello");
guestfs_umount (g, "/");
guestfs_close (g);
cc prog.c -o prog -lguestfs
or:
cc prog.c -o prog `pkg-config libguestfs --cflags --libs`
DESCRIPTION¶
Libguestfs is a library for accessing and modifying disk images and virtual
machines. This manual page documents the C API.
If you are looking for an introduction to libguestfs, see the web site:
<
http://libguestfs.org/>
Each virt tool has its own man page (for a full list, go to "SEE ALSO"
at the end of this file).
The libguestfs FAQ contains many useful answers:
guestfs-faq(1).
For examples of using the API from C, see
guestfs-examples(3). For
examples in other languages, see "USING LIBGUESTFS WITH OTHER PROGRAMMING
LANGUAGES" below.
API OVERVIEW¶
This section provides a gentler overview of the libguestfs API. We also try to
group API calls together, where that may not be obvious from reading about the
individual calls in the main section of this manual.
HANDLES¶
Before you can use libguestfs calls, you have to create a handle. Then you must
add at least one disk image to the handle, followed by launching the handle,
then performing whatever operations you want, and finally closing the handle.
By convention we use the single letter "g" for the name of the
handle variable, although of course you can use any name you want.
The general structure of all libguestfs-using programs looks like this:
guestfs_h *g = guestfs_create ();
/* Call guestfs_add_drive additional times if there are
* multiple disk images.
*/
guestfs_add_drive (g, "guest.img");
/* Most manipulation calls won't work until you've launched
* the handle 'g'. You have to do this _after_ adding drives
* and _before_ other commands.
*/
guestfs_launch (g);
/* Now you can examine what partitions, LVs etc are available.
*/
char **partitions = guestfs_list_partitions (g);
char **logvols = guestfs_lvs (g);
/* To access a filesystem in the image, you must mount it.
*/
guestfs_mount (g, "/dev/sda1", "/");
/* Now you can perform filesystem actions on the guest
* disk image.
*/
guestfs_touch (g, "/hello");
/* This is only needed for libguestfs < 1.5.24. Since then
* it is done automatically when you close the handle. See
* discussion of autosync in this page.
*/
guestfs_sync (g);
/* Close the handle 'g'. */
guestfs_close (g);
The code above doesn't include any error checking. In real code you should check
return values carefully for errors. In general all functions that return
integers return "-1" on error, and all functions that return
pointers return "NULL" on error. See section "ERROR
HANDLING" below for how to handle errors, and consult the documentation
for each function call below to see precisely how they return error
indications. See
guestfs-examples(3) for fully worked examples.
DISK IMAGES¶
The image filename ("guest.img" in the example above) could be a disk
image from a virtual machine, a
dd(1) copy of a physical hard disk, an
actual block device, or simply an empty file of zeroes that you have created
through
posix_fallocate(3). Libguestfs lets you do useful things to all
of these.
The call you should use in modern code for adding drives is
"guestfs_add_drive_opts". To add a disk image, allowing writes, and
specifying that the format is raw, do:
guestfs_add_drive_opts (g, filename,
GUESTFS_ADD_DRIVE_OPTS_FORMAT, "raw",
-1);
You can add a disk read-only using:
guestfs_add_drive_opts (g, filename,
GUESTFS_ADD_DRIVE_OPTS_FORMAT, "raw",
GUESTFS_ADD_DRIVE_OPTS_READONLY, 1,
-1);
or by calling the older function "guestfs_add_drive_ro". In either
case libguestfs won't modify the file.
Be extremely cautious if the disk image is in use, eg. if it is being used by a
virtual machine. Adding it read-write will almost certainly cause disk
corruption, but adding it read-only is safe.
You must add at least one disk image, and you may add multiple disk images. In
the API, the disk images are usually referred to as "/dev/sda" (for
the first one you added), "/dev/sdb" (for the second one you added),
etc.
Once "guestfs_launch" has been called you cannot add any more images.
You can call "guestfs_list_devices" to get a list of the device
names, in the order that you added them. See also "BLOCK DEVICE
NAMING" below.
MOUNTING¶
Before you can read or write files, create directories and so on in a disk image
that contains filesystems, you have to mount those filesystems using
"guestfs_mount_options" or "guestfs_mount_ro". If you
already know that a disk image contains (for example) one partition with a
filesystem on that partition, then you can mount it directly:
guestfs_mount_options (g, "", "/dev/sda1", "/");
where "/dev/sda1" means literally the first partition (1) of the first
disk image that we added ("/dev/sda"). If the disk contains Linux
LVM2 logical volumes you could refer to those instead (eg.
"/dev/VG/LV"). Note that these are libguestfs virtual devices, and
are nothing to do with host devices.
If you are given a disk image and you don't know what it contains then you have
to find out. Libguestfs can do that too: use
"guestfs_list_partitions" and "guestfs_lvs" to list
possible partitions and LVs, and either try mounting each to see what is
mountable, or else examine them with "guestfs_vfs_type" or
"guestfs_file". To list just filesystems, use
"guestfs_list_filesystems".
Libguestfs also has a set of APIs for inspection of unknown disk images (see
"INSPECTION" below). But you might find it easier to look at higher
level programs built on top of libguestfs, in particular
virt-inspector(1).
To mount a filesystem read-only, use "guestfs_mount_ro". There are
several other variations of the "guestfs_mount_*" call.
FILESYSTEM ACCESS AND MODIFICATION¶
The majority of the libguestfs API consists of fairly low-level calls for
accessing and modifying the files, directories, symlinks etc on mounted
filesystems. There are over a hundred such calls which you can find listed in
detail below in this man page, and we don't even pretend to cover them all in
this overview.
Specify filenames as full paths, starting with "/" and including the
mount point.
For example, if you mounted a filesystem at "/" and you want to read
the file called "etc/passwd" then you could do:
char *data = guestfs_cat (g, "/etc/passwd");
This would return "data" as a newly allocated buffer containing the
full content of that file (with some conditions: see also
"DOWNLOADING" below), or "NULL" if there was an error.
As another example, to create a top-level directory on that filesystem called
"var" you would do:
guestfs_mkdir (g, "/var");
To create a symlink you could do:
guestfs_ln_s (g, "/etc/init.d/portmap",
"/etc/rc3.d/S30portmap");
Libguestfs will reject attempts to use relative paths and there is no concept of
a current working directory.
Libguestfs can return errors in many situations: for example if the filesystem
isn't writable, or if a file or directory that you requested doesn't exist. If
you are using the C API (documented here) you have to check for those error
conditions after each call. (Other language bindings turn these errors into
exceptions).
File writes are affected by the per-handle umask, set by calling
"guestfs_umask" and defaulting to 022. See "UMASK".
Since libguestfs 1.18, it is possible to mount the libguestfs filesystem on a
local directory, subject to some restrictions. See "MOUNT LOCAL"
below.
PARTITIONING¶
Libguestfs contains API calls to read, create and modify partition tables on
disk images.
In the common case where you want to create a single partition covering the
whole disk, you should use the "guestfs_part_disk" call:
const char *parttype = "mbr";
if (disk_is_larger_than_2TB)
parttype = "gpt";
guestfs_part_disk (g, "/dev/sda", parttype);
Obviously this effectively wipes anything that was on that disk image before.
LVM2¶
Libguestfs provides access to a large part of the LVM2 API, such as
"guestfs_lvcreate" and "guestfs_vgremove". It won't make
much sense unless you familiarize yourself with the concepts of physical
volumes, volume groups and logical volumes.
This author strongly recommends reading the LVM HOWTO, online at
http://tldp.org/HOWTO/LVM-HOWTO/ <
http://tldp.org/HOWTO/LVM-HOWTO/>.
DOWNLOADING¶
Use "guestfs_cat" to download small, text only files. This call is
limited to files which are less than 2 MB and which cannot contain any ASCII
NUL ("\0") characters. However the API is very simple to use.
"guestfs_read_file" can be used to read files which contain arbitrary
8 bit data, since it returns a (pointer, size) pair. However it is still
limited to "small" files, less than 2 MB.
"guestfs_download" can be used to download any file, with no limits on
content or size (even files larger than 4 GB).
To download multiple files, see "guestfs_tar_out" and
"guestfs_tgz_out".
UPLOADING¶
It's often the case that you want to write a file or files to the disk image.
To write a small file with fixed content, use "guestfs_write". To
create a file of all zeroes, use "guestfs_truncate_size" (sparse) or
"guestfs_fallocate64" (with all disk blocks allocated). There are a
variety of other functions for creating test files, for example
"guestfs_fill" and "guestfs_fill_pattern".
To upload a single file, use "guestfs_upload". This call has no limits
on file content or size (even files larger than 4 GB).
To upload multiple files, see "guestfs_tar_in" and
"guestfs_tgz_in".
However the fastest way to upload
large numbers of arbitrary files is to
turn them into a squashfs or CD ISO (see
mksquashfs(8) and
mkisofs(8)), then attach this using "guestfs_add_drive_ro".
If you add the drive in a predictable way (eg. adding it last after all other
drives) then you can get the device name from "guestfs_list_devices"
and mount it directly using "guestfs_mount_ro". Note that squashfs
images are sometimes non-portable between kernel versions, and they don't
support labels or UUIDs. If you want to pre-build an image or you need to
mount it using a label or UUID, use an ISO image instead.
COPYING¶
There are various different commands for copying between files and devices and
in and out of the guest filesystem. These are summarised in the table below.
- file to file
- Use "guestfs_cp" to copy a single file, or
"guestfs_cp_a" to copy directories recursively.
To copy part of a file (offset and size) use
"guestfs_copy_file_to_file".
- file to device
- device to file
- device to device
- Use "guestfs_copy_file_to_device",
"guestfs_copy_device_to_file", or
"guestfs_copy_device_to_device".
Example: duplicate the contents of an LV:
guestfs_copy_device_to_device (g,
"/dev/VG/Original", "/dev/VG/Copy",
/* -1 marks the end of the list of optional parameters */
-1);
The destination ("/dev/VG/Copy") must be at least as large as the
source ("/dev/VG/Original"). To copy less than the whole source
device, use the optional "size" parameter:
guestfs_copy_device_to_device (g,
"/dev/VG/Original", "/dev/VG/Copy",
GUESTFS_COPY_DEVICE_TO_DEVICE_SIZE, 10000,
-1);
- file on the host to file or device
- Use "guestfs_upload". See "UPLOADING"
above.
- file or device to file on the host
- Use "guestfs_download". See
"DOWNLOADING" above.
UPLOADING AND DOWNLOADING TO PIPES AND FILE DESCRIPTORS¶
Calls like "guestfs_upload", "guestfs_download",
"guestfs_tar_in", "guestfs_tar_out" etc appear to only
take filenames as arguments, so it appears you can only upload and download to
files. However many Un*x-like hosts let you use the special device files
"/dev/stdin", "/dev/stdout", "/dev/stderr" and
"/dev/fd/N" to read and write from stdin, stdout, stderr, and
arbitrary file descriptor N.
For example,
virt-cat(1) writes its output to stdout by doing:
guestfs_download (g, filename, "/dev/stdout");
and you can write tar output to a file descriptor "fd" by doing:
char devfd[64];
snprintf (devfd, sizeof devfd, "/dev/fd/%d", fd);
guestfs_tar_out (g, "/", devfd);
LISTING FILES¶
"guestfs_ll" is just designed for humans to read (mainly when using
the
guestfish(1)-equivalent command "ll").
"guestfs_ls" is a quick way to get a list of files in a directory from
programs, as a flat list of strings.
"guestfs_readdir" is a programmatic way to get a list of files in a
directory, plus additional information about each one. It is more equivalent
to using the
readdir(3) call on a local filesystem.
"guestfs_find" and "guestfs_find0" can be used to
recursively list files.
RUNNING COMMANDS¶
Although libguestfs is primarily an API for manipulating files inside guest
images, we also provide some limited facilities for running commands inside
guests.
There are many limitations to this:
- •
- The kernel version that the command runs under will be
different from what it expects.
- •
- If the command needs to communicate with daemons, then most
likely they won't be running.
- •
- The command will be running in limited memory.
- •
- The network may not be available unless you enable it (see
"guestfs_set_network").
- •
- Only supports Linux guests (not Windows, BSD, etc).
- •
- Architecture limitations (eg. won't work for a PPC guest on
an X86 host).
- •
- For SELinux guests, you may need to enable SELinux and load
policy first. See "SELINUX" in this manpage.
- •
- Security: It is not safe to run commands from
untrusted, possibly malicious guests. These commands may attempt to
exploit your program by sending unexpected output. They could also try to
exploit the Linux kernel or qemu provided by the libguestfs appliance.
They could use the network provided by the libguestfs appliance to bypass
ordinary network partitions and firewalls. They could use the elevated
privileges or different SELinux context of your program to their
advantage.
A secure alternative is to use libguestfs to install a "firstboot"
script (a script which runs when the guest next boots normally), and to
have this script run the commands you want in the normal context of the
running guest, network security and so on. For information about other
security issues, see "SECURITY".
The two main API calls to run commands are "guestfs_command" and
"guestfs_sh" (there are also variations).
The difference is that "guestfs_sh" runs commands using the shell, so
any shell globs, redirections, etc will work.
CONFIGURATION FILES¶
To read and write configuration files in Linux guest filesystems, we strongly
recommend using Augeas. For example, Augeas understands how to read and write,
say, a Linux shadow password file or X.org configuration file, and so avoids
you having to write that code.
The main Augeas calls are bound through the "guestfs_aug_*" APIs. We
don't document Augeas itself here because there is excellent documentation on
the <
http://augeas.net/> website.
If you don't want to use Augeas (you fool!) then try calling
"guestfs_read_lines" to get the file as a list of lines which you
can iterate over.
SELINUX¶
We support SELinux guests. To ensure that labeling happens correctly in SELinux
guests, you need to enable SELinux and load the guest's policy:
- 1.
- Before launching, do:
guestfs_set_selinux (g, 1);
- 2.
- After mounting the guest's filesystem(s), load the policy.
This is best done by running the load_policy(8) command in the
guest itself:
guestfs_sh (g, "/usr/sbin/load_policy");
(Older versions of "load_policy" require you to specify the name
of the policy file).
- 3.
- Optionally, set the security context for the API. The
correct security context to use can only be known by inspecting the guest.
As an example:
guestfs_setcon (g, "unconfined_u:unconfined_r:unconfined_t:s0");
This will work for running commands and editing existing files.
When new files are created, you may need to label them explicitly, for example
by running the external command "restorecon pathname".
UMASK¶
Certain calls are affected by the current file mode creation mask (the
"umask"). In particular ones which create files or directories, such
as "guestfs_touch", "guestfs_mknod" or
"guestfs_mkdir". This affects either the default mode that the file
is created with or modifies the mode that you supply.
The default umask is 022, so files are created with modes such as 0644 and
directories with 0755.
There are two ways to avoid being affected by umask. Either set umask to 0 (call
"guestfs_umask (g, 0)" early after launching). Or call
"guestfs_chmod" after creating each file or directory.
For more information about umask, see
umask(2).
ENCRYPTED DISKS¶
Libguestfs allows you to access Linux guests which have been encrypted using
whole disk encryption that conforms to the Linux Unified Key Setup (LUKS)
standard. This includes nearly all whole disk encryption systems used by
modern Linux guests.
Use "guestfs_vfs_type" to identify LUKS-encrypted block devices (it
returns the string "crypto_LUKS").
Then open these devices by calling "guestfs_luks_open". Obviously you
will require the passphrase!
Opening a LUKS device creates a new device mapper device called
"/dev/mapper/mapname" (where "mapname" is the string you
supply to "guestfs_luks_open"). Reads and writes to this mapper
device are decrypted from and encrypted to the underlying block device
respectively.
LVM volume groups on the device can be made visible by calling
"guestfs_vgscan" followed by "guestfs_vg_activate_all".
The logical volume(s) can now be mounted in the usual way.
Use the reverse process to close a LUKS device. Unmount any logical volumes on
it, deactivate the volume groups by caling "guestfs_vg_activate (g, 0,
["/dev/VG"])". Then close the mapper device by calling
"guestfs_luks_close" on the "/dev/mapper/mapname" device (
not the underlying encrypted block device).
MOUNT LOCAL¶
In libguestfs ≥ 1.18, it is possible to mount the libguestfs filesystem on
a local directory and access it using ordinary POSIX calls and programs.
Availability of this is subject to a number of restrictions: it requires FUSE
(the Filesystem in USErspace), and libfuse must also have been available when
libguestfs was compiled. FUSE may require that a kernel module is loaded, and
it may be necessary to add the current user to a special "fuse"
group. See the documentation for your distribution and
<
http://fuse.sf.net> for further information.
The call to mount the libguestfs filesystem on a local directory is
"guestfs_mount_local" (q.v.) followed by
"guestfs_mount_local_run". The latter does not return until you
unmount the filesystem. The reason is that the call enters the FUSE main loop
and processes kernel requests, turning them into libguestfs calls. An
alternative design would have been to create a background thread to do this,
but libguestfs doesn't require pthreads. This way is also more flexible: for
example the user can create another thread for
"guestfs_mount_local_run".
"guestfs_mount_local" needs a certain amount of time to set up the
mountpoint. The mountpoint is not ready to use until the call returns. At this
point, accesses to the filesystem will block until the main loop is entered
(ie. "guestfs_mount_local_run"). So if you need to start another
process to access the filesystem, put the fork between
"guestfs_mount_local" and "guestfs_mount_local_run".
MOUNT LOCAL COMPATIBILITY
Since local mounting was only added in libguestfs 1.18, and may not be available
even in these builds, you should consider writing code so that it doesn't
depend on this feature, and can fall back to using libguestfs file system
calls.
If libguestfs was compiled without support for "guestfs_mount_local"
then calling it will return an error with errno set to "ENOTSUP"
(see "guestfs_last_errno").
MOUNT LOCAL PERFORMANCE
Libguestfs on top of FUSE performs quite poorly. For best performance do not use
it. Use ordinary libguestfs filesystem calls, upload, download etc. instead.
INSPECTION¶
Libguestfs has APIs for inspecting an unknown disk image to find out if it
contains operating systems, an install CD or a live CD. (These APIs used to be
in a separate Perl-only library called
Sys::Guestfs::Lib(3) but since
version 1.5.3 the most frequently used part of this library has been rewritten
in C and moved into the core code).
Add all disks belonging to the unknown virtual machine and call
"guestfs_launch" in the usual way.
Then call "guestfs_inspect_os". This function uses other libguestfs
calls and certain heuristics, and returns a list of operating systems that
were found. An empty list means none were found. A single element is the root
filesystem of the operating system. For dual- or multi-boot guests, multiple
roots can be returned, each one corresponding to a separate operating system.
(Multi-boot virtual machines are extremely rare in the world of
virtualization, but since this scenario can happen, we have built libguestfs
to deal with it.)
For each root, you can then call various "guestfs_inspect_get_*"
functions to get additional details about that operating system. For example,
call "guestfs_inspect_get_type" to return the string
"windows" or "linux" for Windows and Linux-based operating
systems respectively.
Un*x-like and Linux-based operating systems usually consist of several
filesystems which are mounted at boot time (for example, a separate boot
partition mounted on "/boot"). The inspection rules are able to
detect how filesystems correspond to mount points. Call
"guestfs_inspect_get_mountpoints" to get this mapping. It might
return a hash table like this example:
/boot => /dev/sda1
/ => /dev/vg_guest/lv_root
/usr => /dev/vg_guest/lv_usr
The caller can then make calls to "guestfs_mount_options" to mount the
filesystems as suggested.
Be careful to mount filesystems in the right order (eg. "/" before
"/usr"). Sorting the keys of the hash by length, shortest first,
should work.
Inspection currently only works for some common operating systems. Contributors
are welcome to send patches for other operating systems that we currently
cannot detect.
Encrypted disks must be opened before inspection. See "ENCRYPTED
DISKS" for more details. The "guestfs_inspect_os" function just
ignores any encrypted devices.
A note on the implementation: The call "guestfs_inspect_os" performs
inspection and caches the results in the guest handle. Subsequent calls to
"guestfs_inspect_get_*" return this cached information, but
do
not re-read the disks. If you change the content of the guest disks, you
can redo inspection by calling "guestfs_inspect_os" again.
("guestfs_inspect_list_applications" works a little differently from
the other calls and does read the disks. See documentation for that function
for details).
INSPECTING INSTALL DISKS
Libguestfs (since 1.9.4) can detect some install disks, install CDs, live CDs
and more.
Call "guestfs_inspect_get_format" to return the format of the
operating system, which currently can be "installed" (a regular
operating system) or "installer" (some sort of install disk).
Further information is available about the operating system that can be
installed using the regular inspection APIs like
"guestfs_inspect_get_product_name",
"guestfs_inspect_get_major_version" etc.
Some additional information specific to installer disks is also available from
the "guestfs_inspect_is_live",
"guestfs_inspect_is_netinst" and
"guestfs_inspect_is_multipart" calls.
SPECIAL CONSIDERATIONS FOR WINDOWS GUESTS¶
Libguestfs can mount NTFS partitions. It does this using the
http://www.ntfs-3g.org/ <
http://www.ntfs-3g.org/> driver.
DRIVE LETTERS AND PATHS
DOS and Windows still use drive letters, and the filesystems are always treated
as case insensitive by Windows itself, and therefore you might find a Windows
configuration file referring to a path like "c:\windows\system32".
When the filesystem is mounted in libguestfs, that directory might be referred
to as "/WINDOWS/System32".
Drive letter mappings can be found using inspection (see "INSPECTION"
and "guestfs_inspect_get_drive_mappings")
Dealing with separator characters (backslash vs forward slash) is outside the
scope of libguestfs, but usually a simple character replacement will work.
To resolve the case insensitivity of paths, call
"guestfs_case_sensitive_path".
ACCESSING THE WINDOWS REGISTRY
Libguestfs also provides some help for decoding Windows Registry
"hive" files, through the library "hivex" which is part of
the libguestfs project although ships as a separate tarball. You have to
locate and download the hive file(s) yourself, and then pass them to
"hivex" functions. See also the programs
hivexml(1),
hivexsh(1),
hivexregedit(1) and
virt-win-reg(1) for more
help on this issue.
SYMLINKS ON NTFS-3G FILESYSTEMS
Ntfs-3g tries to rewrite "Junction Points" and NTFS "symbolic
links" to provide something which looks like a Linux symlink. The way it
tries to do the rewriting is described here:
http://www.tuxera.com/community/ntfs-3g-advanced/junction-points-and-symbolic-links/
<
http://www.tuxera.com/community/ntfs-3g-advanced/junction-points-and-symbolic-links/>
The essential problem is that ntfs-3g simply does not have enough information to
do a correct job. NTFS links can contain drive letters and references to
external device GUIDs that ntfs-3g has no way of resolving. It is almost
certainly the case that libguestfs callers should ignore what ntfs-3g does
(ie. don't use "guestfs_readlink" on NTFS volumes).
Instead if you encounter a symbolic link on an ntfs-3g filesystem, use
"guestfs_lgetxattr" to read the "system.ntfs_reparse_data"
extended attribute, and read the raw reparse data from that (you can find the
format documented in various places around the web).
EXTENDED ATTRIBUTES ON NTFS-3G FILESYSTEMS
There are other useful extended attributes that can be read from ntfs-3g
filesystems (using "guestfs_getxattr"). See:
http://www.tuxera.com/community/ntfs-3g-advanced/extended-attributes/
<
http://www.tuxera.com/community/ntfs-3g-advanced/extended-attributes/>
RESIZE2FS ERRORS¶
The "guestfs_resize2fs", "guestfs_resize2fs_size" and
"guestfs_resize2fs_M" calls are used to resize ext2/3/4 filesystems.
The underlying program (
resize2fs(8)) requires that the filesystem is
clean and recently fsck'd before you can resize it. Also, if the resize
operation fails for some reason, then you had to call fsck the filesystem
again to fix it.
In libguestfs "lt" 1.17.14, you usually had to call
"guestfs_e2fsck_f" before the resize. However, in "ge"
1.17.14,
e2fsck(8) is called automatically before the resize, so you no
longer need to do this.
The
resize2fs(8) program can still fail, in which case it prints an error
message similar to:
Please run 'e2fsck -fy <device>' to fix the filesystem
after the aborted resize operation.
You can do this by calling "guestfs_e2fsck" with the
"forceall" option. However in the context of disk images, it is
usually better to avoid this situation, eg. by rolling back to an earlier
snapshot, or by copying and resizing and on failure going back to the
original.
USING LIBGUESTFS WITH OTHER PROGRAMMING LANGUAGES¶
Although we don't want to discourage you from using the C API, we will mention
here that the same API is also available in other languages.
The API is broadly identical in all supported languages. This means that the C
call "guestfs_add_drive_ro(g,file)" is
"$g->add_drive_ro($file)" in Perl,
"g.add_drive_ro(file)" in Python, and "g#add_drive_ro
file" in OCaml. In other words, a straightforward, predictable
isomorphism between each language.
Error messages are automatically transformed into exceptions if the language
supports it.
We don't try to "object orientify" parts of the API in OO languages,
although contributors are welcome to write higher level APIs above what we
provide in their favourite languages if they wish.
- C++
- You can use the guestfs.h header file from C++
programs. The C++ API is identical to the C API. C++ classes and
exceptions are not used.
- C#
- The C# bindings are highly experimental. Please read the
warnings at the top of "csharp/Libguestfs.cs".
- Erlang
- See guestfs-erlang(3).
- GObject
- Experimental GObject bindings (with GObject Introspection
support) are available. See the "gobject" directory in the
source.
- Haskell
- This is the only language binding that is working but
incomplete. Only calls which return simple integers have been bound in
Haskell, and we are looking for help to complete this binding.
- Java
- Full documentation is contained in the Javadoc which is
distributed with libguestfs. For examples, see
guestfs-java(3).
- OCaml
- See guestfs-ocaml(3).
- Perl
- See guestfs-perl(3) and Sys::Guestfs(3).
- PHP
- For documentation see "README-PHP" supplied with
libguestfs sources or in the php-libguestfs package for your distribution.
The PHP binding only works correctly on 64 bit machines.
- Python
- See guestfs-python(3).
- Ruby
- See guestfs-ruby(3).
For JRuby, use the Java bindings.
- shell scripts
- See guestfish(1).
LIBGUESTFS GOTCHAS¶
<
http://en.wikipedia.org/wiki/Gotcha_(programming)>: "A feature of a
system [...] that works in the way it is documented but is counterintuitive
and almost invites mistakes."
Since we developed libguestfs and the associated tools, there are several things
we would have designed differently, but are now stuck with for backwards
compatibility or other reasons. If there is ever a libguestfs 2.0 release, you
can expect these to change. Beware of them.
- Autosync / forgetting to sync.
- Update: Autosync is enabled by default for all API
users starting from libguestfs 1.5.24. This section only applies to older
versions.
When modifying a filesystem from C or another language, you must
unmount all filesystems and call "guestfs_sync" explicitly
before you close the libguestfs handle. You can also call:
guestfs_set_autosync (g, 1);
to have the unmount/sync done automatically for you when the handle 'g' is
closed. (This feature is called "autosync",
"guestfs_set_autosync" q.v.)
If you forget to do this, then it is entirely possible that your changes
won't be written out, or will be partially written, or (very rarely) that
you'll get disk corruption.
Note that in guestfish(3) autosync is the default. So quick and dirty
guestfish scripts that forget to sync will work just fine, which can make
this very puzzling if you are trying to debug a problem.
- Mount option "-o sync" should not be the
default.
- Update: "guestfs_mount" no longer adds any
options starting from libguestfs 1.13.16. This section only applies to
older versions.
If you use "guestfs_mount", then "-o sync,noatime" are
added implicitly. However "-o sync" does not add any reliability
benefit, but does have a very large performance impact.
The work around is to use "guestfs_mount_options" and set the
mount options that you actually want to use.
- Read-only should be the default.
- In guestfish(3), --ro should be the default,
and you should have to specify --rw if you want to make changes to
the image.
This would reduce the potential to corrupt live VM images.
Note that many filesystems change the disk when you just mount and unmount,
even if you didn't perform any writes. You need to use
"guestfs_add_drive_ro" to guarantee that the disk is not
changed.
- guestfish command line is hard to use.
- "guestfish disk.img" doesn't do what people
expect (open "disk.img" for examination). It tries to run a
guestfish command "disk.img" which doesn't exist, so it fails.
In earlier versions of guestfish the error message was also unintuitive,
but we have corrected this since. Like the Bourne shell, we should have
used "guestfish -c command" to run commands.
- guestfish megabyte modifiers don't work right on all
commands
- In recent guestfish you can use "1M" to mean 1
megabyte (and similarly for other modifiers). What guestfish actually does
is to multiply the number part by the modifier part and pass the result to
the C API. However this doesn't work for a few APIs which aren't expecting
bytes, but are already expecting some other unit (eg. megabytes).
The most common is "guestfs_lvcreate". The guestfish command:
lvcreate LV VG 100M
does not do what you might expect. Instead because
"guestfs_lvcreate" is already expecting megabytes, this tries to
create a 100 terabyte (100 megabytes * megabytes) logical volume.
The error message you get from this is also a little obscure.
This could be fixed in the generator by specially marking parameters and
return values which take bytes or other units.
- Ambiguity between devices and paths
- There is a subtle ambiguity in the API between a device
name (eg. "/dev/sdb2") and a similar pathname. A file might just
happen to be called "sdb2" in the directory "/dev"
(consider some non-Unix VM image).
In the current API we usually resolve this ambiguity by having two separate
calls, for example "guestfs_checksum" and
"guestfs_checksum_device". Some API calls are ambiguous and
(incorrectly) resolve the problem by detecting if the path supplied begins
with "/dev/".
To avoid both the ambiguity and the need to duplicate some calls, we could
make paths/devices into structured names. One way to do this would be to
use a notation like grub ("hd(0,0)"), although nobody really
likes this aspect of grub. Another way would be to use a structured type,
equivalent to this OCaml type:
type path = Path of string | Device of int | Partition of int * int
which would allow you to pass arguments like:
Path "/foo/bar"
Device 1 (* /dev/sdb, or perhaps /dev/sda *)
Partition (1, 2) (* /dev/sdb2 (or is it /dev/sda2 or /dev/sdb3?) *)
Path "/dev/sdb2" (* not a device *)
As you can see there are still problems to resolve even with this
representation. Also consider how it might work in guestfish.
KEYS AND PASSPHRASES¶
Certain libguestfs calls take a parameter that contains sensitive key material,
passed in as a C string.
In the future we would hope to change the libguestfs implementation so that keys
are
mlock(2)-ed into physical RAM, and thus can never end up in swap.
However this is
not done at the moment, because of the complexity of
such an implementation.
Therefore you should be aware that any key parameter you pass to libguestfs
might end up being written out to the swap partition. If this is a concern,
scrub the swap partition or don't use libguestfs on encrypted devices.
MULTIPLE HANDLES AND MULTIPLE THREADS¶
All high-level libguestfs actions are synchronous. If you want to use libguestfs
asynchronously then you must create a thread.
Only use the handle from a single thread. Either use the handle exclusively from
one thread, or provide your own mutex so that two threads cannot issue calls
on the same handle at the same time.
See the graphical program guestfs-browser for one possible architecture for
multithreaded programs using libvirt and libguestfs.
PATH¶
Libguestfs needs a supermin appliance, which it finds by looking along an
internal path.
By default it looks for these in the directory "$libdir/guestfs" (eg.
"/usr/local/lib/guestfs" or "/usr/lib64/guestfs").
Use "guestfs_set_path" or set the environment variable
"LIBGUESTFS_PATH" to change the directories that libguestfs will
search in. The value is a colon-separated list of paths. The current directory
is
not searched unless the path contains an empty element or
".". For example "LIBGUESTFS_PATH=:/usr/lib/guestfs" would
search the current directory and then "/usr/lib/guestfs".
QEMU WRAPPERS¶
If you want to compile your own qemu, run qemu from a non-standard location, or
pass extra arguments to qemu, then you can write a shell-script wrapper around
qemu.
There is one important rule to remember: you
must "exec
qemu" as the last command in the shell script (so that qemu
replaces the shell and becomes the direct child of the libguestfs-using
program). If you don't do this, then the qemu process won't be cleaned up
correctly.
Here is an example of a wrapper, where I have built my own copy of qemu from
source:
#!/bin/sh -
qemudir=/home/rjones/d/qemu
exec $qemudir/x86_64-softmmu/qemu-system-x86_64 -L $qemudir/pc-bios "$@"
Save this script as "/tmp/qemu.wrapper" (or wherever), "chmod
+x", and then use it by setting the LIBGUESTFS_QEMU environment variable.
For example:
LIBGUESTFS_QEMU=/tmp/qemu.wrapper guestfish
Note that libguestfs also calls qemu with the -help and -version options in
order to determine features.
Wrappers can also be used to edit the options passed to qemu. In the following
example, the "-machine ..." option ("-machine" and the
following argument) are removed from the command line and replaced with
"-machine pc,accel=tcg". The while loop iterates over the options
until it finds the right one to remove, putting the remaining options into the
"args" array.
#!/bin/bash -
i=0
while [ $# -gt 0 ]; do
case "$1" in
-machine)
shift 2;;
*)
args[i]="$1"
(( i++ ))
shift ;;
esac
done
exec qemu-kvm -machine pc,accel=tcg "${args[@]}"
ATTACHING TO RUNNING DAEMONS¶
Note (1): This is
highly experimental and has a tendency to eat
babies. Use with caution.
Note (2): This section explains how to attach to a running daemon from a
low level perspective. For most users, simply using virt tools such as
guestfish(1) with the
--live option will "just work".
Using guestfs_set_attach_method
By calling "guestfs_set_attach_method" you can change how the library
connects to the "guestfsd" daemon in "guestfs_launch"
(read "ARCHITECTURE" for some background).
The normal attach method is "appliance", where a small appliance is
created containing the daemon, and then the library connects to this.
Setting attach method to "unix:
path" (where
path is the
path of a Unix domain socket) causes "guestfs_launch" to connect to
an existing daemon over the Unix domain socket.
The normal use for this is to connect to a running virtual machine that contains
a "guestfsd" daemon, and send commands so you can read and write
files inside the live virtual machine.
Using guestfs_add_domain with live flag
"guestfs_add_domain" provides some help for getting the correct attach
method. If you pass the "live" option to this function, then (if the
virtual machine is running) it will examine the libvirt XML looking for a
virtio-serial channel to connect to:
<domain>
...
<devices>
...
<channel type='unix'>
<source mode='bind' path='/path/to/socket'/>
<target type='virtio' name='org.libguestfs.channel.0'/>
</channel>
...
</devices>
</domain>
"guestfs_add_domain" extracts "/path/to/socket" and sets the
attach method to "unix:/path/to/socket".
Some of the libguestfs tools (including guestfish) support a
--live
option which is passed through to "guestfs_add_domain" thus allowing
you to attach to and modify live virtual machines.
The virtual machine needs to have been set up beforehand so that it has the
virtio-serial channel and so that guestfsd is running inside it.
ABI GUARANTEE¶
We guarantee the libguestfs ABI (binary interface), for public, high-level
actions as outlined in this section. Although we will deprecate some actions,
for example if they get replaced by newer calls, we will keep the old actions
forever. This allows you the developer to program in confidence against the
libguestfs API.
BLOCK DEVICE NAMING¶
In the kernel there is now quite a profusion of schemata for naming block
devices (in this context, by
block device I mean a physical or virtual
hard drive). The original Linux IDE driver used names starting with
"/dev/hd*". SCSI devices have historically used a different naming
scheme, "/dev/sd*". When the Linux kernel
libata driver
became a popular replacement for the old IDE driver (particularly for SATA
devices) those devices also used the "/dev/sd*" scheme. Additionally
we now have virtual machines with paravirtualized drivers. This has created
several different naming systems, such as "/dev/vd*" for virtio
disks and "/dev/xvd*" for Xen PV disks.
As discussed above, libguestfs uses a qemu appliance running an embedded Linux
kernel to access block devices. We can run a variety of appliances based on a
variety of Linux kernels.
This causes a problem for libguestfs because many API calls use device or
partition names. Working scripts and the recipe (example) scripts that we make
available over the internet could fail if the naming scheme changes.
Therefore libguestfs defines "/dev/sd*" as the
standard naming
scheme. Internally "/dev/sd*" names are translated, if
necessary, to other names as required. For example, under RHEL 5 which uses
the "/dev/hd*" scheme, any device parameter "/dev/sda2" is
translated to "/dev/hda2" transparently.
Note that this
only applies to parameters. The
"guestfs_list_devices", "guestfs_list_partitions" and
similar calls return the true names of the devices and partitions as known to
the appliance.
ALGORITHM FOR BLOCK DEVICE NAME TRANSLATION
Usually this translation is transparent. However in some (very rare) cases you
may need to know the exact algorithm. Such cases include where you use
"guestfs_config" to add a mixture of virtio and IDE devices to the
qemu-based appliance, so have a mixture of "/dev/sd*" and
"/dev/vd*" devices.
The algorithm is applied only to
parameters which are known to be either
device or partition names. Return values from functions such as
"guestfs_list_devices" are never changed.
- •
- Is the string a parameter which is a device or partition
name?
- •
- Does the string begin with "/dev/sd"?
- •
- Does the named device exist? If so, we use that device.
However if not then we continue with this algorithm.
- •
- Replace initial "/dev/sd" string with
"/dev/hd".
For example, change "/dev/sda2" to "/dev/hda2".
If that named device exists, use it. If not, continue.
- •
- Replace initial "/dev/sd" string with
"/dev/vd".
If that named device exists, use it. If not, return an error.
PORTABILITY CONCERNS WITH BLOCK DEVICE NAMING
Although the standard naming scheme and automatic translation is useful for
simple programs and guestfish scripts, for larger programs it is best not to
rely on this mechanism.
Where possible for maximum future portability programs using libguestfs should
use these future-proof techniques:
- •
- Use "guestfs_list_devices" or
"guestfs_list_partitions" to list actual device names, and then
use those names directly.
Since those device names exist by definition, they will never be
translated.
- •
- Use higher level ways to identify filesystems, such as LVM
names, UUIDs and filesystem labels.
SECURITY¶
This section discusses security implications of using libguestfs, particularly
with untrusted or malicious guests or disk images.
GENERAL SECURITY CONSIDERATIONS¶
Be careful with any files or data that you download from a guest (by
"download" we mean not just the "guestfs_download" command
but any command that reads files, filenames, directories or anything else from
a disk image). An attacker could manipulate the data to fool your program into
doing the wrong thing. Consider cases such as:
- •
- the data (file etc) not being present
- •
- being present but empty
- •
- being much larger than normal
- •
- containing arbitrary 8 bit data
- •
- being in an unexpected character encoding
- •
- containing homoglyphs.
SECURITY OF MOUNTING FILESYSTEMS¶
When you mount a filesystem under Linux, mistakes in the kernel filesystem (VFS)
module can sometimes be escalated into exploits by deliberately creating a
malicious, malformed filesystem. These exploits are very severe for two
reasons. Firstly there are very many filesystem drivers in the kernel, and
many of them are infrequently used and not much developer attention has been
paid to the code. Linux userspace helps potential crackers by detecting the
filesystem type and automatically choosing the right VFS driver, even if that
filesystem type is obscure or unexpected for the administrator. Secondly, a
kernel-level exploit is like a local root exploit (worse in some ways), giving
immediate and total access to the system right down to the hardware level.
That explains why you should never mount a filesystem from an untrusted guest on
your host kernel. How about libguestfs? We run a Linux kernel inside a qemu
virtual machine, usually running as a non-root user. The attacker would need
to write a filesystem which first exploited the kernel, and then exploited
either qemu virtualization (eg. a faulty qemu driver) or the libguestfs
protocol, and finally to be as serious as the host kernel exploit it would
need to escalate its privileges to root. This multi-step escalation, performed
by a static piece of data, is thought to be extremely hard to do, although we
never say 'never' about security issues.
In any case callers can reduce the attack surface by forcing the filesystem type
when mounting (use "guestfs_mount_vfs").
PROTOCOL SECURITY¶
The protocol is designed to be secure, being based on RFC 4506 (XDR) with a
defined upper message size. However a program that uses libguestfs must also
take care - for example you can write a program that downloads a binary from a
disk image and executes it locally, and no amount of protocol security will
save you from the consequences.
INSPECTION SECURITY¶
Parts of the inspection API (see "INSPECTION") return untrusted
strings directly from the guest, and these could contain any 8 bit data.
Callers should be careful to escape these before printing them to a structured
file (for example, use HTML escaping if creating a web page).
Guest configuration may be altered in unusual ways by the administrator of the
virtual machine, and may not reflect reality (particularly for untrusted or
actively malicious guests). For example we parse the hostname from
configuration files like "/etc/sysconfig/network" that we find in
the guest, but the guest administrator can easily manipulate these files to
provide the wrong hostname.
The inspection API parses guest configuration using two external libraries:
Augeas (Linux configuration) and hivex (Windows Registry). Both are designed
to be robust in the face of malicious data, although denial of service attacks
are still possible, for example with oversized configuration files.
RUNNING UNTRUSTED GUEST COMMANDS¶
Be very cautious about running commands from the guest. By running a command in
the guest, you are giving CPU time to a binary that you do not control, under
the same user account as the library, albeit wrapped in qemu virtualization.
More information and alternatives can be found in the section "RUNNING
COMMANDS".
CVE-2010-3851¶
https://bugzilla.redhat.com/642934
This security bug concerns the automatic disk format detection that qemu does on
disk images.
A raw disk image is just the raw bytes, there is no header. Other disk images
like qcow2 contain a special header. Qemu deals with this by looking for one
of the known headers, and if none is found then assuming the disk image must
be raw.
This allows a guest which has been given a raw disk image to write some other
header. At next boot (or when the disk image is accessed by libguestfs) qemu
would do autodetection and think the disk image format was, say, qcow2 based
on the header written by the guest.
This in itself would not be a problem, but qcow2 offers many features, one of
which is to allow a disk image to refer to another image (called the
"backing disk"). It does this by placing the path to the backing
disk into the qcow2 header. This path is not validated and could point to any
host file (eg. "/etc/passwd"). The backing disk is then exposed
through "holes" in the qcow2 disk image, which of course is
completely under the control of the attacker.
In libguestfs this is rather hard to exploit except under two circumstances:
- 1.
- You have enabled the network or have opened the disk in
write mode.
- 2.
- You are also running untrusted code from the guest (see
"RUNNING COMMANDS").
The way to avoid this is to specify the expected disk format when adding disks
(the optional "format" option to
"guestfs_add_drive_opts"). You should always do this if the disk is
raw format, and it's a good idea for other cases too.
For disks added from libvirt using calls like "guestfs_add_domain",
the format is fetched from libvirt and passed through.
For libguestfs tools, use the
--format command line parameter as
appropriate.
CONNECTION MANAGEMENT¶
guestfs_h *¶
"guestfs_h" is the opaque type representing a connection handle.
Create a handle by calling "guestfs_create". Call
"guestfs_close" to free the handle and release all resources used.
For information on using multiple handles and threads, see the section
"MULTIPLE HANDLES AND MULTIPLE THREADS" above.
guestfs_create¶
guestfs_h *guestfs_create (void);
Create a connection handle.
On success this returns a non-NULL pointer to a handle. On error it returns
NULL.
You have to "configure" the handle after creating it. This includes
calling "guestfs_add_drive_opts" (or one of the equivalent calls) on
the handle at least once.
After configuring the handle, you have to call "guestfs_launch".
You may also want to configure error handling for the handle. See the
"ERROR HANDLING" section below.
guestfs_close¶
void guestfs_close (guestfs_h *g);
This closes the connection handle and frees up all resources used.
If autosync was set on the handle and the handle was launched, then this
implicitly calls various functions to unmount filesystems and sync the disk.
See "guestfs_set_autosync" for more details.
If a close callback was set on the handle, then it is called.
ERROR HANDLING¶
API functions can return errors. For example, almost all functions that return
"int" will return "-1" to indicate an error.
Additional information is available for errors: an error message string and
optionally an error number (errno) if the thing that failed was a system call.
You can get at the additional information about the last error on the handle by
calling "guestfs_last_error", "guestfs_last_errno", and/or
by setting up an error handler with "guestfs_set_error_handler".
When the handle is created, a default error handler is installed which prints
the error message string to "stderr". For small short-running
command line programs it is sufficient to do:
if (guestfs_launch (g) == -1)
exit (EXIT_FAILURE);
since the default error handler will ensure that an error message has been
printed to "stderr" before the program exits.
For other programs the caller will almost certainly want to install an alternate
error handler or do error handling in-line like this:
/* This disables the default behaviour of printing errors
on stderr. */
guestfs_set_error_handler (g, NULL, NULL);
if (guestfs_launch (g) == -1) {
/* Examine the error message and print it etc. */
char *msg = guestfs_last_error (g);
int errnum = guestfs_last_errno (g);
fprintf (stderr, "%s", msg);
if (errnum != 0)
fprintf (stderr, ": %s", strerror (errnum));
fprintf (stderr, "\n");
/* ... */
}
Out of memory errors are handled differently. The default action is to call
abort(3). If this is undesirable, then you can set a handler using
"guestfs_set_out_of_memory_handler".
"guestfs_create" returns "NULL" if the handle cannot be
created, and because there is no handle if this happens there is no way to get
additional error information. However "guestfs_create" is supposed
to be a lightweight operation which can only fail because of insufficient
memory (it returns NULL in this case).
guestfs_last_error¶
const char *guestfs_last_error (guestfs_h *g);
This returns the last error message that happened on "g". If there has
not been an error since the handle was created, then this returns
"NULL".
The lifetime of the returned string is until the next error occurs, or
"guestfs_close" is called.
guestfs_last_errno¶
int guestfs_last_errno (guestfs_h *g);
This returns the last error number (errno) that happened on "g".
If successful, an errno integer not equal to zero is returned.
If no error, this returns 0. This call can return 0 in three situations:
- 1.
- There has not been any error on the handle.
- 2.
- There has been an error but the errno was meaningless. This
corresponds to the case where the error did not come from a failed system
call, but for some other reason.
- 3.
- There was an error from a failed system call, but for some
reason the errno was not captured and returned. This usually indicates a
bug in libguestfs.
Libguestfs tries to convert the errno from inside the applicance into a
corresponding errno for the caller (not entirely trivial: the appliance might
be running a completely different operating system from the library and error
numbers are not standardized across Un*xen). If this could not be done, then
the error is translated to "EINVAL". In practice this should only
happen in very rare circumstances.
guestfs_set_error_handler¶
typedef void (*guestfs_error_handler_cb) (guestfs_h *g,
void *opaque,
const char *msg);
void guestfs_set_error_handler (guestfs_h *g,
guestfs_error_handler_cb cb,
void *opaque);
The callback "cb" will be called if there is an error. The parameters
passed to the callback are an opaque data pointer and the error message
string.
"errno" is not passed to the callback. To get that the callback must
call "guestfs_last_errno".
Note that the message string "msg" is freed as soon as the callback
function returns, so if you want to stash it somewhere you must make your own
copy.
The default handler prints messages on "stderr".
If you set "cb" to "NULL" then
no handler is called.
guestfs_get_error_handler¶
guestfs_error_handler_cb guestfs_get_error_handler (guestfs_h *g,
void **opaque_rtn);
Returns the current error handler callback.
guestfs_set_out_of_memory_handler¶
typedef void (*guestfs_abort_cb) (void);
void guestfs_set_out_of_memory_handler (guestfs_h *g,
guestfs_abort_cb);
The callback "cb" will be called if there is an out of memory
situation.
Note this callback must not return.
The default is to call
abort(3).
You cannot set "cb" to "NULL". You can't ignore out of
memory situations.
guestfs_get_out_of_memory_handler¶
guestfs_abort_fn guestfs_get_out_of_memory_handler (guestfs_h *g);
This returns the current out of memory handler.
API CALLS¶
guestfs_add_cdrom¶
int
guestfs_add_cdrom (guestfs_h *g,
const char *filename);
This function is deprecated. In new code, use the
"guestfs_add_drive_opts" call instead.
Deprecated functions will not be removed from the API, but the fact that they
are deprecated indicates that there are problems with correct use of these
functions.
This function adds a virtual CD-ROM disk image to the guest.
This is equivalent to the qemu parameter
-cdrom filename.
Notes:
- •
- This call checks for the existence of "filename".
This stops you from specifying other types of drive which are supported by
qemu such as "nbd:" and "http:" URLs. To specify
those, use the general "guestfs_config" call instead.
- •
- If you just want to add an ISO file (often you use this as
an efficient way to transfer large files into the guest), then you should
probably use "guestfs_add_drive_ro" instead.
This function returns 0 on success or -1 on error.
(Added in 0.3)
guestfs_add_domain¶
int
guestfs_add_domain (guestfs_h *g,
const char *dom,
...);
You may supply a list of optional arguments to this call. Use zero or more of
the following pairs of parameters, and terminate the list with "-1"
on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_ADD_DOMAIN_LIBVIRTURI, const char *libvirturi,
GUESTFS_ADD_DOMAIN_READONLY, int readonly,
GUESTFS_ADD_DOMAIN_IFACE, const char *iface,
GUESTFS_ADD_DOMAIN_LIVE, int live,
GUESTFS_ADD_DOMAIN_ALLOWUUID, int allowuuid,
GUESTFS_ADD_DOMAIN_READONLYDISK, const char *readonlydisk,
This function adds the disk(s) attached to the named libvirt domain
"dom". It works by connecting to libvirt, requesting the domain and
domain XML from libvirt, parsing it for disks, and calling
"guestfs_add_drive_opts" on each one.
The number of disks added is returned. This operation is atomic: if an error is
returned, then no disks are added.
This function does some minimal checks to make sure the libvirt domain is not
running (unless "readonly" is true). In a future version we will try
to acquire the libvirt lock on each disk.
Disks must be accessible locally. This often means that adding disks from a
remote libvirt connection (see <
http://libvirt.org/remote.html>) will
fail unless those disks are accessible via the same device path locally too.
The optional "libvirturi" parameter sets the libvirt URI (see
<
http://libvirt.org/uri.html>). If this is not set then we connect to
the default libvirt URI (or one set through an environment variable, see the
libvirt documentation for full details).
The optional "live" flag controls whether this call will try to
connect to a running virtual machine "guestfsd" process if it sees a
suitable <channel> element in the libvirt XML definition. The default
(if the flag is omitted) is never to try. See "ATTACHING TO RUNNING
DAEMONS" in
guestfs(3) for more information.
If the "allowuuid" flag is true (default is false) then a UUID
may be passed instead of the domain name. The "dom" string is
treated as a UUID first and looked up, and if that lookup fails then we treat
"dom" as a name as usual.
The optional "readonlydisk" parameter controls what we do for disks
which are marked <readonly/> in the libvirt XML. Possible values are:
- readonlydisk = "error"
- If "readonly" is false:
The whole call is aborted with an error if any disk with the
<readonly/> flag is found.
If "readonly" is true:
Disks with the <readonly/> flag are added read-only.
- readonlydisk = "read"
- If "readonly" is false:
Disks with the <readonly/> flag are added read-only. Other disks are
added read/write.
If "readonly" is true:
Disks with the <readonly/> flag are added read-only.
- readonlydisk = "write" (default)
- If "readonly" is false:
Disks with the <readonly/> flag are added read/write.
If "readonly" is true:
Disks with the <readonly/> flag are added read-only.
- readonlydisk = "ignore"
- If "readonly" is true or false:
Disks with the <readonly/> flag are skipped.
The other optional parameters are passed directly through to
"guestfs_add_drive_opts".
On error this function returns -1.
(Added in 1.7.4)
guestfs_add_domain_va¶
int
guestfs_add_domain_va (guestfs_h *g,
const char *dom,
va_list args);
This is the "va_list variant" of "guestfs_add_domain".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_add_domain_argv¶
int
guestfs_add_domain_argv (guestfs_h *g,
const char *dom,
const struct guestfs_add_domain_argv *optargs);
This is the "argv variant" of "guestfs_add_domain".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_add_drive¶
int
guestfs_add_drive (guestfs_h *g,
const char *filename);
This function is the equivalent of calling "guestfs_add_drive_opts"
with no optional parameters, so the disk is added writable, with the format
being detected automatically.
Automatic detection of the format opens you up to a potential security hole when
dealing with untrusted raw-format images. See CVE-2010-3851 and RHBZ#642934.
Specifying the format closes this security hole. Therefore you should think
about replacing calls to this function with calls to
"guestfs_add_drive_opts", and specifying the format.
This function returns 0 on success or -1 on error.
(Added in 0.3)
guestfs_add_drive_opts¶
int
guestfs_add_drive_opts (guestfs_h *g,
const char *filename,
...);
You may supply a list of optional arguments to this call. Use zero or more of
the following pairs of parameters, and terminate the list with "-1"
on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_ADD_DRIVE_OPTS_READONLY, int readonly,
GUESTFS_ADD_DRIVE_OPTS_FORMAT, const char *format,
GUESTFS_ADD_DRIVE_OPTS_IFACE, const char *iface,
GUESTFS_ADD_DRIVE_OPTS_NAME, const char *name,
This function adds a virtual machine disk image "filename" to
libguestfs. The first time you call this function, the disk appears as
"/dev/sda", the second time as "/dev/sdb", and so on.
You don't necessarily need to be root when using libguestfs. However you
obviously do need sufficient permissions to access the filename for whatever
operations you want to perform (ie. read access if you just want to read the
image or write access if you want to modify the image).
This call checks that "filename" exists.
The optional arguments are:
- "readonly"
- If true then the image is treated as read-only. Writes are
still allowed, but they are stored in a temporary snapshot overlay which
is discarded at the end. The disk that you add is not modified.
- "format"
- This forces the image format. If you omit this (or use
"guestfs_add_drive" or "guestfs_add_drive_ro") then
the format is automatically detected. Possible formats include
"raw" and "qcow2".
Automatic detection of the format opens you up to a potential security hole
when dealing with untrusted raw-format images. See CVE-2010-3851 and
RHBZ#642934. Specifying the format closes this security hole.
- "iface"
- This rarely-used option lets you emulate the behaviour of
the deprecated "guestfs_add_drive_with_if" call (q.v.)
- "name"
- The name the drive had in the original guest, e.g.
/dev/sdb. This is used as a hint to the guest inspection process if it is
available.
This function returns 0 on success or -1 on error.
(Added in 1.5.23)
guestfs_add_drive_opts_va¶
int
guestfs_add_drive_opts_va (guestfs_h *g,
const char *filename,
va_list args);
This is the "va_list variant" of "guestfs_add_drive_opts".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_add_drive_opts_argv¶
int
guestfs_add_drive_opts_argv (guestfs_h *g,
const char *filename,
const struct guestfs_add_drive_opts_argv *optargs);
This is the "argv variant" of "guestfs_add_drive_opts".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_add_drive_ro¶
int
guestfs_add_drive_ro (guestfs_h *g,
const char *filename);
This function is the equivalent of calling "guestfs_add_drive_opts"
with the optional parameter "GUESTFS_ADD_DRIVE_OPTS_READONLY" set to
1, so the disk is added read-only, with the format being detected
automatically.
This function returns 0 on success or -1 on error.
(Added in 1.0.38)
guestfs_add_drive_ro_with_if¶
int
guestfs_add_drive_ro_with_if (guestfs_h *g,
const char *filename,
const char *iface);
This function is deprecated. In new code, use the
"guestfs_add_drive_opts" call instead.
Deprecated functions will not be removed from the API, but the fact that they
are deprecated indicates that there are problems with correct use of these
functions.
This is the same as "guestfs_add_drive_ro" but it allows you to
specify the QEMU interface emulation to use at run time.
This function returns 0 on success or -1 on error.
(Added in 1.0.84)
guestfs_add_drive_with_if¶
int
guestfs_add_drive_with_if (guestfs_h *g,
const char *filename,
const char *iface);
This function is deprecated. In new code, use the
"guestfs_add_drive_opts" call instead.
Deprecated functions will not be removed from the API, but the fact that they
are deprecated indicates that there are problems with correct use of these
functions.
This is the same as "guestfs_add_drive" but it allows you to specify
the QEMU interface emulation to use at run time.
This function returns 0 on success or -1 on error.
(Added in 1.0.84)
guestfs_aug_clear¶
int
guestfs_aug_clear (guestfs_h *g,
const char *augpath);
Set the value associated with "path" to "NULL". This is the
same as the
augtool(1) "clear" command.
This function returns 0 on success or -1 on error.
(Added in 1.3.4)
guestfs_aug_close¶
int
guestfs_aug_close (guestfs_h *g);
Close the current Augeas handle and free up any resources used by it. After
calling this, you have to call "guestfs_aug_init" again before you
can use any other Augeas functions.
This function returns 0 on success or -1 on error.
(Added in 0.7)
guestfs_aug_defnode¶
struct guestfs_int_bool *
guestfs_aug_defnode (guestfs_h *g,
const char *name,
const char *expr,
const char *val);
Defines a variable "name" whose value is the result of evaluating
"expr".
If "expr" evaluates to an empty nodeset, a node is created, equivalent
to calling "guestfs_aug_set" "expr", "value".
"name" will be the nodeset containing that single node.
On success this returns a pair containing the number of nodes in the nodeset,
and a boolean flag if a node was created.
This function returns a "struct guestfs_int_bool *", or NULL if there
was an error.
The caller must call
"guestfs_free_int_bool" after use.
(Added in 0.7)
guestfs_aug_defvar¶
int
guestfs_aug_defvar (guestfs_h *g,
const char *name,
const char *expr);
Defines an Augeas variable "name" whose value is the result of
evaluating "expr". If "expr" is NULL, then
"name" is undefined.
On success this returns the number of nodes in "expr", or 0 if
"expr" evaluates to something which is not a nodeset.
On error this function returns -1.
(Added in 0.7)
guestfs_aug_get¶
char *
guestfs_aug_get (guestfs_h *g,
const char *augpath);
Look up the value associated with "path". If "path" matches
exactly one node, the "value" is returned.
This function returns a string, or NULL on error.
The caller must free the
returned string after use.
(Added in 0.7)
guestfs_aug_init¶
int
guestfs_aug_init (guestfs_h *g,
const char *root,
int flags);
Create a new Augeas handle for editing configuration files. If there was any
previous Augeas handle associated with this guestfs session, then it is
closed.
You must call this before using any other "guestfs_aug_*" commands.
"root" is the filesystem root. "root" must not be NULL, use
"/" instead.
The flags are the same as the flags defined in <augeas.h>, the logical
or of the following integers:
- "AUG_SAVE_BACKUP" = 1
- Keep the original file with a ".augsave"
extension.
- "AUG_SAVE_NEWFILE" = 2
- Save changes into a file with extension
".augnew", and do not overwrite original. Overrides
"AUG_SAVE_BACKUP".
- "AUG_TYPE_CHECK" = 4
- Typecheck lenses.
This option is only useful when debugging Augeas lenses. Use of this option
may require additional memory for the libguestfs appliance. You may need
to set the "LIBGUESTFS_MEMSIZE" environment variable or call
"guestfs_set_memsize".
- "AUG_NO_STDINC" = 8
- Do not use standard load path for modules.
- "AUG_SAVE_NOOP" = 16
- Make save a no-op, just record what would have been
changed.
- "AUG_NO_LOAD" = 32
- Do not load the tree in "guestfs_aug_init".
To close the handle, you can call "guestfs_aug_close".
To find out more about Augeas, see <
http://augeas.net/>.
This function returns 0 on success or -1 on error.
(Added in 0.7)
guestfs_aug_insert¶
int
guestfs_aug_insert (guestfs_h *g,
const char *augpath,
const char *label,
int before);
Create a new sibling "label" for "path", inserting it into
the tree before or after "path" (depending on the boolean flag
"before").
"path" must match exactly one existing node in the tree, and
"label" must be a label, ie. not contain "/",
"*" or end with a bracketed index "[N]".
This function returns 0 on success or -1 on error.
(Added in 0.7)
guestfs_aug_load¶
int
guestfs_aug_load (guestfs_h *g);
Load files into the tree.
See "aug_load" in the Augeas documentation for the full gory details.
This function returns 0 on success or -1 on error.
(Added in 0.7)
guestfs_aug_ls¶
char **
guestfs_aug_ls (guestfs_h *g,
const char *augpath);
This is just a shortcut for listing "guestfs_aug_match"
"path/*" and sorting the resulting nodes into alphabetical order.
This function returns a NULL-terminated array of strings (like
environ(3)), or NULL if there was an error.
The caller must free the
strings and the array after use.
(Added in 0.8)
guestfs_aug_match¶
char **
guestfs_aug_match (guestfs_h *g,
const char *augpath);
Returns a list of paths which match the path expression "path". The
returned paths are sufficiently qualified so that they match exactly one node
in the current tree.
This function returns a NULL-terminated array of strings (like
environ(3)), or NULL if there was an error.
The caller must free the
strings and the array after use.
(Added in 0.7)
guestfs_aug_mv¶
int
guestfs_aug_mv (guestfs_h *g,
const char *src,
const char *dest);
Move the node "src" to "dest". "src" must match
exactly one node. "dest" is overwritten if it exists.
This function returns 0 on success or -1 on error.
(Added in 0.7)
guestfs_aug_rm¶
int
guestfs_aug_rm (guestfs_h *g,
const char *augpath);
Remove "path" and all of its children.
On success this returns the number of entries which were removed.
On error this function returns -1.
(Added in 0.7)
guestfs_aug_save¶
int
guestfs_aug_save (guestfs_h *g);
This writes all pending changes to disk.
The flags which were passed to "guestfs_aug_init" affect exactly how
files are saved.
This function returns 0 on success or -1 on error.
(Added in 0.7)
guestfs_aug_set¶
int
guestfs_aug_set (guestfs_h *g,
const char *augpath,
const char *val);
Set the value associated with "path" to "val".
In the Augeas API, it is possible to clear a node by setting the value to NULL.
Due to an oversight in the libguestfs API you cannot do that with this call.
Instead you must use the "guestfs_aug_clear" call.
This function returns 0 on success or -1 on error.
(Added in 0.7)
guestfs_available¶
int
guestfs_available (guestfs_h *g,
char *const *groups);
This command is used to check the availability of some groups of functionality
in the appliance, which not all builds of the libguestfs appliance will be
able to provide.
The libguestfs groups, and the functions that those groups correspond to, are
listed in "AVAILABILITY" in
guestfs(3). You can also fetch
this list at runtime by calling "guestfs_available_all_groups".
The argument "groups" is a list of group names, eg:
"["inotify", "augeas"]" would check for the
availability of the Linux inotify functions and Augeas (configuration file
editing) functions.
The command returns no error if
all requested groups are available.
It fails with an error if one or more of the requested groups is unavailable in
the appliance.
If an unknown group name is included in the list of groups then an error is
always returned.
Notes:
- •
- You must call "guestfs_launch" before calling
this function.
The reason is because we don't know what groups are supported by the
appliance/daemon until it is running and can be queried.
- •
- If a group of functions is available, this does not
necessarily mean that they will work. You still have to check for errors
when calling individual API functions even if they are available.
- •
- It is usually the job of distro packagers to build complete
functionality into the libguestfs appliance. Upstream libguestfs, if built
from source with all requirements satisfied, will support everything.
- •
- This call was added in version 1.0.80. In previous versions
of libguestfs all you could do would be to speculatively execute a command
to find out if the daemon implemented it. See also
"guestfs_version".
This function returns 0 on success or -1 on error.
(Added in 1.0.80)
guestfs_available_all_groups¶
char **
guestfs_available_all_groups (guestfs_h *g);
This command returns a list of all optional groups that this daemon knows about.
Note this returns both supported and unsupported groups. To find out which
ones the daemon can actually support you have to call
"guestfs_available" on each member of the returned list.
See also "guestfs_available" and "AVAILABILITY" in
guestfs(3).
This function returns a NULL-terminated array of strings (like
environ(3)), or NULL if there was an error.
The caller must free the
strings and the array after use.
(Added in 1.3.15)
guestfs_base64_in¶
int
guestfs_base64_in (guestfs_h *g,
const char *base64file,
const char *filename);
This command uploads base64-encoded data from "base64file" to
"filename".
This function returns 0 on success or -1 on error.
(Added in 1.3.5)
guestfs_base64_out¶
int
guestfs_base64_out (guestfs_h *g,
const char *filename,
const char *base64file);
This command downloads the contents of "filename", writing it out to
local file "base64file" encoded as base64.
This function returns 0 on success or -1 on error.
(Added in 1.3.5)
guestfs_blkid¶
char **
guestfs_blkid (guestfs_h *g,
const char *device);
This command returns block device attributes for "device". The
following fields are usually present in the returned hash. Other fields may
also be present.
- "UUID"
- The uuid of this device.
- "LABEL"
- The label of this device.
- "VERSION"
- The version of blkid command.
- "TYPE"
- The filesystem type or RAID of this device.
- "USAGE"
- The usage of this device, for example
"filesystem" or "raid".
This function returns a NULL-terminated array of strings, or NULL if there was
an error. The array of strings will always have length "2n+1", where
"n" keys and values alternate, followed by the trailing NULL entry.
The caller must free the strings and the array after use.
(Added in 1.15.9)
guestfs_blockdev_flushbufs¶
int
guestfs_blockdev_flushbufs (guestfs_h *g,
const char *device);
This tells the kernel to flush internal buffers associated with
"device".
This uses the
blockdev(8) command.
This function returns 0 on success or -1 on error.
(Added in 0.9.3)
guestfs_blockdev_getbsz¶
int
guestfs_blockdev_getbsz (guestfs_h *g,
const char *device);
This returns the block size of a device.
(Note this is different from both
size in blocks and
filesystem block
size).
This uses the
blockdev(8) command.
On error this function returns -1.
(Added in 0.9.3)
guestfs_blockdev_getro¶
int
guestfs_blockdev_getro (guestfs_h *g,
const char *device);
Returns a boolean indicating if the block device is read-only (true if
read-only, false if not).
This uses the
blockdev(8) command.
This function returns a C truth value on success or -1 on error.
(Added in 0.9.3)
guestfs_blockdev_getsize64¶
int64_t
guestfs_blockdev_getsize64 (guestfs_h *g,
const char *device);
This returns the size of the device in bytes.
See also "guestfs_blockdev_getsz".
This uses the
blockdev(8) command.
On error this function returns -1.
(Added in 0.9.3)
guestfs_blockdev_getss¶
int
guestfs_blockdev_getss (guestfs_h *g,
const char *device);
This returns the size of sectors on a block device. Usually 512, but can be
larger for modern devices.
(Note, this is not the size in sectors, use "guestfs_blockdev_getsz"
for that).
This uses the
blockdev(8) command.
On error this function returns -1.
(Added in 0.9.3)
guestfs_blockdev_getsz¶
int64_t
guestfs_blockdev_getsz (guestfs_h *g,
const char *device);
This returns the size of the device in units of 512-byte sectors (even if the
sectorsize isn't 512 bytes ... weird).
See also "guestfs_blockdev_getss" for the real sector size of the
device, and "guestfs_blockdev_getsize64" for the more useful
size
in bytes.
This uses the
blockdev(8) command.
On error this function returns -1.
(Added in 0.9.3)
guestfs_blockdev_rereadpt¶
int
guestfs_blockdev_rereadpt (guestfs_h *g,
const char *device);
Reread the partition table on "device".
This uses the
blockdev(8) command.
This function returns 0 on success or -1 on error.
(Added in 0.9.3)
guestfs_blockdev_setbsz¶
int
guestfs_blockdev_setbsz (guestfs_h *g,
const char *device,
int blocksize);
This sets the block size of a device.
(Note this is different from both
size in blocks and
filesystem block
size).
This uses the
blockdev(8) command.
This function returns 0 on success or -1 on error.
(Added in 0.9.3)
guestfs_blockdev_setro¶
int
guestfs_blockdev_setro (guestfs_h *g,
const char *device);
Sets the block device named "device" to read-only.
This uses the
blockdev(8) command.
This function returns 0 on success or -1 on error.
(Added in 0.9.3)
guestfs_blockdev_setrw¶
int
guestfs_blockdev_setrw (guestfs_h *g,
const char *device);
Sets the block device named "device" to read-write.
This uses the
blockdev(8) command.
This function returns 0 on success or -1 on error.
(Added in 0.9.3)
guestfs_btrfs_device_add¶
int
guestfs_btrfs_device_add (guestfs_h *g,
char *const *devices,
const char *fs);
Add the list of device(s) in "devices" to the btrfs filesystem mounted
at "fs". If "devices" is an empty list, this does nothing.
This function returns 0 on success or -1 on error.
(Added in 1.17.35)
guestfs_btrfs_device_delete¶
int
guestfs_btrfs_device_delete (guestfs_h *g,
char *const *devices,
const char *fs);
Remove the "devices" from the btrfs filesystem mounted at
"fs". If "devices" is an empty list, this does nothing.
This function returns 0 on success or -1 on error.
(Added in 1.17.35)
guestfs_btrfs_filesystem_balance¶
int
guestfs_btrfs_filesystem_balance (guestfs_h *g,
const char *fs);
Balance the chunks in the btrfs filesystem mounted at "fs" across the
underlying devices.
This function returns 0 on success or -1 on error.
(Added in 1.17.35)
guestfs_btrfs_filesystem_resize¶
int
guestfs_btrfs_filesystem_resize (guestfs_h *g,
const char *mountpoint,
...);
You may supply a list of optional arguments to this call. Use zero or more of
the following pairs of parameters, and terminate the list with "-1"
on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_BTRFS_FILESYSTEM_RESIZE_SIZE, int64_t size,
This command resizes a btrfs filesystem.
Note that unlike other resize calls, the filesystem has to be mounted and the
parameter is the mountpoint not the device (this is a requirement of btrfs
itself).
The optional parameters are:
- "size"
- The new size (in bytes) of the filesystem. If omitted, the
filesystem is resized to the maximum size.
See also
btrfs(8).
This function returns 0 on success or -1 on error.
(Added in 1.11.17)
guestfs_btrfs_filesystem_resize_va¶
int
guestfs_btrfs_filesystem_resize_va (guestfs_h *g,
const char *mountpoint,
va_list args);
This is the "va_list variant" of
"guestfs_btrfs_filesystem_resize".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_btrfs_filesystem_resize_argv¶
int
guestfs_btrfs_filesystem_resize_argv (guestfs_h *g,
const char *mountpoint,
const struct guestfs_btrfs_filesystem_resize_argv *optargs);
This is the "argv variant" of
"guestfs_btrfs_filesystem_resize".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_btrfs_filesystem_sync¶
int
guestfs_btrfs_filesystem_sync (guestfs_h *g,
const char *fs);
Force sync on the btrfs filesystem mounted at "fs".
This function returns 0 on success or -1 on error.
(Added in 1.17.35)
guestfs_btrfs_fsck¶
int
guestfs_btrfs_fsck (guestfs_h *g,
const char *device,
...);
You may supply a list of optional arguments to this call. Use zero or more of
the following pairs of parameters, and terminate the list with "-1"
on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_BTRFS_FSCK_SUPERBLOCK, int64_t superblock,
GUESTFS_BTRFS_FSCK_REPAIR, int repair,
Used to check a btrfs filesystem, "device" is the device file where
the filesystem is stored.
This function returns 0 on success or -1 on error.
(Added in 1.17.43)
guestfs_btrfs_fsck_va¶
int
guestfs_btrfs_fsck_va (guestfs_h *g,
const char *device,
va_list args);
This is the "va_list variant" of "guestfs_btrfs_fsck".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_btrfs_fsck_argv¶
int
guestfs_btrfs_fsck_argv (guestfs_h *g,
const char *device,
const struct guestfs_btrfs_fsck_argv *optargs);
This is the "argv variant" of "guestfs_btrfs_fsck".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_btrfs_set_seeding¶
int
guestfs_btrfs_set_seeding (guestfs_h *g,
const char *device,
int seeding);
Enable or disable the seeding feature of a device that contains a btrfs
filesystem.
This function returns 0 on success or -1 on error.
(Added in 1.17.43)
guestfs_btrfs_subvolume_create¶
int
guestfs_btrfs_subvolume_create (guestfs_h *g,
const char *dest);
Create a btrfs subvolume. The "dest" argument is the destination
directory and the name of the snapshot, in the form
"/path/to/dest/name".
This function returns 0 on success or -1 on error.
(Added in 1.17.35)
guestfs_btrfs_subvolume_delete¶
int
guestfs_btrfs_subvolume_delete (guestfs_h *g,
const char *subvolume);
Delete the named btrfs subvolume.
This function returns 0 on success or -1 on error.
(Added in 1.17.35)
guestfs_btrfs_subvolume_list¶
struct guestfs_btrfssubvolume_list *
guestfs_btrfs_subvolume_list (guestfs_h *g,
const char *fs);
List the btrfs snapshots and subvolumes of the btrfs filesystem which is mounted
at "fs".
This function returns a "struct guestfs_btrfssubvolume_list *", or
NULL if there was an error.
The caller must call
"guestfs_free_btrfssubvolume_list" after use.
(Added in 1.17.35)
guestfs_btrfs_subvolume_set_default¶
int
guestfs_btrfs_subvolume_set_default (guestfs_h *g,
int64_t id,
const char *fs);
Set the subvolume of the btrfs filesystem "fs" which will be mounted
by default. See "guestfs_btrfs_subvolume_list" to get a list of
subvolumes.
This function returns 0 on success or -1 on error.
(Added in 1.17.35)
guestfs_btrfs_subvolume_snapshot¶
int
guestfs_btrfs_subvolume_snapshot (guestfs_h *g,
const char *source,
const char *dest);
Create a writable snapshot of the btrfs subvolume "source". The
"dest" argument is the destination directory and the name of the
snapshot, in the form "/path/to/dest/name".
This function returns 0 on success or -1 on error.
(Added in 1.17.35)
guestfs_case_sensitive_path¶
char *
guestfs_case_sensitive_path (guestfs_h *g,
const char *path);
This can be used to resolve case insensitive paths on a filesystem which is case
sensitive. The use case is to resolve paths which you have read from Windows
configuration files or the Windows Registry, to the true path.
The command handles a peculiarity of the Linux ntfs-3g filesystem driver (and
probably others), which is that although the underlying filesystem is
case-insensitive, the driver exports the filesystem to Linux as
case-sensitive.
One consequence of this is that special directories such as
"c:\windows" may appear as "/WINDOWS" or
"/windows" (or other things) depending on the precise details of how
they were created. In Windows itself this would not be a problem.
Bug or feature? You decide:
http://www.tuxera.com/community/ntfs-3g-faq/#posixfilenames1
<
http://www.tuxera.com/community/ntfs-3g-faq/#posixfilenames1>
This function resolves the true case of each element in the path and returns the
case-sensitive path.
Thus "guestfs_case_sensitive_path" ("/Windows/System32")
might return "/WINDOWS/system32" (the exact return value would
depend on details of how the directories were originally created under
Windows).
Note: This function does not handle drive names, backslashes etc.
See also "guestfs_realpath".
This function returns a string, or NULL on error.
The caller must free the
returned string after use.
(Added in 1.0.75)
guestfs_cat¶
char *
guestfs_cat (guestfs_h *g,
const char *path);
Return the contents of the file named "path".
Note that this function cannot correctly handle binary files (specifically,
files containing "\0" character which is treated as end of string).
For those you need to use the "guestfs_read_file" or
"guestfs_download" functions which have a more complex interface.
This function returns a string, or NULL on error.
The caller must free the
returned string after use.
Because of the message protocol, there is a transfer limit of somewhere between
2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
(Added in 0.4)
guestfs_checksum¶
char *
guestfs_checksum (guestfs_h *g,
const char *csumtype,
const char *path);
This call computes the MD5, SHAx or CRC checksum of the file named
"path".
The type of checksum to compute is given by the "csumtype" parameter
which must have one of the following values:
- "crc"
- Compute the cyclic redundancy check (CRC) specified by
POSIX for the "cksum" command.
- "md5"
- Compute the MD5 hash (using the "md5sum"
program).
- "sha1"
- Compute the SHA1 hash (using the "sha1sum"
program).
- "sha224"
- Compute the SHA224 hash (using the "sha224sum"
program).
- "sha256"
- Compute the SHA256 hash (using the "sha256sum"
program).
- "sha384"
- Compute the SHA384 hash (using the "sha384sum"
program).
- "sha512"
- Compute the SHA512 hash (using the "sha512sum"
program).
The checksum is returned as a printable string.
To get the checksum for a device, use "guestfs_checksum_device".
To get the checksums for many files, use "guestfs_checksums_out".
This function returns a string, or NULL on error.
The caller must free the
returned string after use.
(Added in 1.0.2)
guestfs_checksum_device¶
char *
guestfs_checksum_device (guestfs_h *g,
const char *csumtype,
const char *device);
This call computes the MD5, SHAx or CRC checksum of the contents of the device
named "device". For the types of checksums supported see the
"guestfs_checksum" command.
This function returns a string, or NULL on error.
The caller must free the
returned string after use.
(Added in 1.3.2)
guestfs_checksums_out¶
int
guestfs_checksums_out (guestfs_h *g,
const char *csumtype,
const char *directory,
const char *sumsfile);
This command computes the checksums of all regular files in
"directory" and then emits a list of those checksums to the local
output file "sumsfile".
This can be used for verifying the integrity of a virtual machine. However to be
properly secure you should pay attention to the output of the checksum command
(it uses the ones from GNU coreutils). In particular when the filename is not
printable, coreutils uses a special backslash syntax. For more information,
see the GNU coreutils info file.
This function returns 0 on success or -1 on error.
(Added in 1.3.7)
guestfs_chmod¶
int
guestfs_chmod (guestfs_h *g,
int mode,
const char *path);
Change the mode (permissions) of "path" to "mode". Only
numeric modes are supported.
Note: When using this command from guestfish, "mode" by default
would be decimal, unless you prefix it with 0 to get octal, ie. use 0700 not
700.
The mode actually set is affected by the umask.
This function returns 0 on success or -1 on error.
(Added in 0.8)
guestfs_chown¶
int
guestfs_chown (guestfs_h *g,
int owner,
int group,
const char *path);
Change the file owner to "owner" and group to "group".
Only numeric uid and gid are supported. If you want to use names, you will need
to locate and parse the password file yourself (Augeas support makes this
relatively easy).
This function returns 0 on success or -1 on error.
(Added in 0.8)
guestfs_command¶
char *
guestfs_command (guestfs_h *g,
char *const *arguments);
This call runs a command from the guest filesystem. The filesystem must be
mounted, and must contain a compatible operating system (ie. something Linux,
with the same or compatible processor architecture).
The single parameter is an argv-style list of arguments. The first element is
the name of the program to run. Subsequent elements are parameters. The list
must be non-empty (ie. must contain a program name). Note that the command
runs directly, and is
not invoked via the shell (see
"guestfs_sh").
The return value is anything printed to
stdout by the command.
If the command returns a non-zero exit status, then this function returns an
error message. The error message string is the content of
stderr from
the command.
The $PATH environment variable will contain at least "/usr/bin" and
"/bin". If you require a program from another location, you should
provide the full path in the first parameter.
Shared libraries and data files required by the program must be available on
filesystems which are mounted in the correct places. It is the caller's
responsibility to ensure all filesystems that are needed are mounted at the
right locations.
This function returns a string, or NULL on error.
The caller must free the
returned string after use.
Because of the message protocol, there is a transfer limit of somewhere between
2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
(Added in 0.9.1)
guestfs_command_lines¶
char **
guestfs_command_lines (guestfs_h *g,
char *const *arguments);
This is the same as "guestfs_command", but splits the result into a
list of lines.
See also: "guestfs_sh_lines"
This function returns a NULL-terminated array of strings (like
environ(3)), or NULL if there was an error.
The caller must free the
strings and the array after use.
Because of the message protocol, there is a transfer limit of somewhere between
2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
(Added in 0.9.1)
guestfs_compress_device_out¶
int
guestfs_compress_device_out (guestfs_h *g,
const char *ctype,
const char *device,
const char *zdevice,
...);
You may supply a list of optional arguments to this call. Use zero or more of
the following pairs of parameters, and terminate the list with "-1"
on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_COMPRESS_DEVICE_OUT_LEVEL, int level,
This command compresses "device" and writes it out to the local file
"zdevice".
The "ctype" and optional "level" parameters have the same
meaning as in "guestfs_compress_out".
This function returns 0 on success or -1 on error.
(Added in 1.13.15)
guestfs_compress_device_out_va¶
int
guestfs_compress_device_out_va (guestfs_h *g,
const char *ctype,
const char *device,
const char *zdevice,
va_list args);
This is the "va_list variant" of
"guestfs_compress_device_out".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_compress_device_out_argv¶
int
guestfs_compress_device_out_argv (guestfs_h *g,
const char *ctype,
const char *device,
const char *zdevice,
const struct guestfs_compress_device_out_argv *optargs);
This is the "argv variant" of "guestfs_compress_device_out".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_compress_out¶
int
guestfs_compress_out (guestfs_h *g,
const char *ctype,
const char *file,
const char *zfile,
...);
You may supply a list of optional arguments to this call. Use zero or more of
the following pairs of parameters, and terminate the list with "-1"
on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_COMPRESS_OUT_LEVEL, int level,
This command compresses "file" and writes it out to the local file
"zfile".
The compression program used is controlled by the "ctype" parameter.
Currently this includes: "compress", "gzip",
"bzip2", "xz" or "lzop". Some compression types
may not be supported by particular builds of libguestfs, in which case you
will get an error containing the substring "not supported".
The optional "level" parameter controls compression level. The meaning
and default for this parameter depends on the compression program being used.
This function returns 0 on success or -1 on error.
(Added in 1.13.15)
guestfs_compress_out_va¶
int
guestfs_compress_out_va (guestfs_h *g,
const char *ctype,
const char *file,
const char *zfile,
va_list args);
This is the "va_list variant" of "guestfs_compress_out".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_compress_out_argv¶
int
guestfs_compress_out_argv (guestfs_h *g,
const char *ctype,
const char *file,
const char *zfile,
const struct guestfs_compress_out_argv *optargs);
This is the "argv variant" of "guestfs_compress_out".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_config¶
int
guestfs_config (guestfs_h *g,
const char *qemuparam,
const char *qemuvalue);
This can be used to add arbitrary qemu command line parameters of the form
-param value. Actually it's not quite arbitrary - we prevent you from
setting some parameters which would interfere with parameters that we use.
The first character of "param" string must be a "-" (dash).
"value" can be NULL.
This function returns 0 on success or -1 on error.
(Added in 0.3)
guestfs_copy_device_to_device¶
int
guestfs_copy_device_to_device (guestfs_h *g,
const char *src,
const char *dest,
...);
You may supply a list of optional arguments to this call. Use zero or more of
the following pairs of parameters, and terminate the list with "-1"
on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_COPY_DEVICE_TO_DEVICE_SRCOFFSET, int64_t srcoffset,
GUESTFS_COPY_DEVICE_TO_DEVICE_DESTOFFSET, int64_t destoffset,
GUESTFS_COPY_DEVICE_TO_DEVICE_SIZE, int64_t size,
The four calls "guestfs_copy_device_to_device",
"guestfs_copy_device_to_file",
"guestfs_copy_file_to_device", and
"guestfs_copy_file_to_file" let you copy from a source (device|file)
to a destination (device|file).
Partial copies can be made since you can specify optionally the source offset,
destination offset and size to copy. These values are all specified in bytes.
If not given, the offsets both default to zero, and the size defaults to
copying as much as possible until we hit the end of the source.
The source and destination may be the same object. However overlapping regions
may not be copied correctly.
If the destination is a file, it is created if required. If the destination file
is not large enough, it is extended.
This function returns 0 on success or -1 on error.
This long-running command can generate progress notification messages so that
the caller can display a progress bar or indicator. To receive these messages,
the caller must register a progress event callback. See
"GUESTFS_EVENT_PROGRESS" in
guestfs(3).
(Added in 1.13.25)
guestfs_copy_device_to_device_va¶
int
guestfs_copy_device_to_device_va (guestfs_h *g,
const char *src,
const char *dest,
va_list args);
This is the "va_list variant" of
"guestfs_copy_device_to_device".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_copy_device_to_device_argv¶
int
guestfs_copy_device_to_device_argv (guestfs_h *g,
const char *src,
const char *dest,
const struct guestfs_copy_device_to_device_argv *optargs);
This is the "argv variant" of
"guestfs_copy_device_to_device".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_copy_device_to_file¶
int
guestfs_copy_device_to_file (guestfs_h *g,
const char *src,
const char *dest,
...);
You may supply a list of optional arguments to this call. Use zero or more of
the following pairs of parameters, and terminate the list with "-1"
on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_COPY_DEVICE_TO_FILE_SRCOFFSET, int64_t srcoffset,
GUESTFS_COPY_DEVICE_TO_FILE_DESTOFFSET, int64_t destoffset,
GUESTFS_COPY_DEVICE_TO_FILE_SIZE, int64_t size,
See "guestfs_copy_device_to_device" for a general overview of this
call.
This function returns 0 on success or -1 on error.
This long-running command can generate progress notification messages so that
the caller can display a progress bar or indicator. To receive these messages,
the caller must register a progress event callback. See
"GUESTFS_EVENT_PROGRESS" in
guestfs(3).
(Added in 1.13.25)
guestfs_copy_device_to_file_va¶
int
guestfs_copy_device_to_file_va (guestfs_h *g,
const char *src,
const char *dest,
va_list args);
This is the "va_list variant" of
"guestfs_copy_device_to_file".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_copy_device_to_file_argv¶
int
guestfs_copy_device_to_file_argv (guestfs_h *g,
const char *src,
const char *dest,
const struct guestfs_copy_device_to_file_argv *optargs);
This is the "argv variant" of "guestfs_copy_device_to_file".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_copy_file_to_device¶
int
guestfs_copy_file_to_device (guestfs_h *g,
const char *src,
const char *dest,
...);
You may supply a list of optional arguments to this call. Use zero or more of
the following pairs of parameters, and terminate the list with "-1"
on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_COPY_FILE_TO_DEVICE_SRCOFFSET, int64_t srcoffset,
GUESTFS_COPY_FILE_TO_DEVICE_DESTOFFSET, int64_t destoffset,
GUESTFS_COPY_FILE_TO_DEVICE_SIZE, int64_t size,
See "guestfs_copy_device_to_device" for a general overview of this
call.
This function returns 0 on success or -1 on error.
This long-running command can generate progress notification messages so that
the caller can display a progress bar or indicator. To receive these messages,
the caller must register a progress event callback. See
"GUESTFS_EVENT_PROGRESS" in
guestfs(3).
(Added in 1.13.25)
guestfs_copy_file_to_device_va¶
int
guestfs_copy_file_to_device_va (guestfs_h *g,
const char *src,
const char *dest,
va_list args);
This is the "va_list variant" of
"guestfs_copy_file_to_device".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_copy_file_to_device_argv¶
int
guestfs_copy_file_to_device_argv (guestfs_h *g,
const char *src,
const char *dest,
const struct guestfs_copy_file_to_device_argv *optargs);
This is the "argv variant" of "guestfs_copy_file_to_device".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_copy_file_to_file¶
int
guestfs_copy_file_to_file (guestfs_h *g,
const char *src,
const char *dest,
...);
You may supply a list of optional arguments to this call. Use zero or more of
the following pairs of parameters, and terminate the list with "-1"
on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_COPY_FILE_TO_FILE_SRCOFFSET, int64_t srcoffset,
GUESTFS_COPY_FILE_TO_FILE_DESTOFFSET, int64_t destoffset,
GUESTFS_COPY_FILE_TO_FILE_SIZE, int64_t size,
See "guestfs_copy_device_to_device" for a general overview of this
call.
This is
not the function you want for copying files. This is for copying
blocks within existing files. See "guestfs_cp",
"guestfs_cp_a" and "guestfs_mv" for general file copying
and moving functions.
This function returns 0 on success or -1 on error.
This long-running command can generate progress notification messages so that
the caller can display a progress bar or indicator. To receive these messages,
the caller must register a progress event callback. See
"GUESTFS_EVENT_PROGRESS" in
guestfs(3).
(Added in 1.13.25)
guestfs_copy_file_to_file_va¶
int
guestfs_copy_file_to_file_va (guestfs_h *g,
const char *src,
const char *dest,
va_list args);
This is the "va_list variant" of
"guestfs_copy_file_to_file".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_copy_file_to_file_argv¶
int
guestfs_copy_file_to_file_argv (guestfs_h *g,
const char *src,
const char *dest,
const struct guestfs_copy_file_to_file_argv *optargs);
This is the "argv variant" of "guestfs_copy_file_to_file".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_copy_size¶
int
guestfs_copy_size (guestfs_h *g,
const char *src,
const char *dest,
int64_t size);
This function is deprecated. In new code, use the
"guestfs_copy_device_to_device" call instead.
Deprecated functions will not be removed from the API, but the fact that they
are deprecated indicates that there are problems with correct use of these
functions.
This command copies exactly "size" bytes from one source device or
file "src" to another destination device or file "dest".
Note this will fail if the source is too short or if the destination is not
large enough.
This function returns 0 on success or -1 on error.
This long-running command can generate progress notification messages so that
the caller can display a progress bar or indicator. To receive these messages,
the caller must register a progress event callback. See
"GUESTFS_EVENT_PROGRESS" in
guestfs(3).
(Added in 1.0.87)
guestfs_cp¶
int
guestfs_cp (guestfs_h *g,
const char *src,
const char *dest);
This copies a file from "src" to "dest" where
"dest" is either a destination filename or destination directory.
This function returns 0 on success or -1 on error.
(Added in 1.0.18)
guestfs_cp_a¶
int
guestfs_cp_a (guestfs_h *g,
const char *src,
const char *dest);
This copies a file or directory from "src" to "dest"
recursively using the "cp -a" command.
This function returns 0 on success or -1 on error.
(Added in 1.0.18)
guestfs_dd¶
int
guestfs_dd (guestfs_h *g,
const char *src,
const char *dest);
This function is deprecated. In new code, use the
"guestfs_copy_device_to_device" call instead.
Deprecated functions will not be removed from the API, but the fact that they
are deprecated indicates that there are problems with correct use of these
functions.
This command copies from one source device or file "src" to another
destination device or file "dest". Normally you would use this to
copy to or from a device or partition, for example to duplicate a filesystem.
If the destination is a device, it must be as large or larger than the source
file or device, otherwise the copy will fail. This command cannot do partial
copies (see "guestfs_copy_device_to_device").
This function returns 0 on success or -1 on error.
(Added in 1.0.80)
guestfs_df¶
char *
guestfs_df (guestfs_h *g);
This command runs the "df" command to report disk space used.
This command is mostly useful for interactive sessions. It is
not
intended that you try to parse the output string. Use
"guestfs_statvfs" from programs.
This function returns a string, or NULL on error.
The caller must free the
returned string after use.
(Added in 1.0.54)
guestfs_df_h¶
char *
guestfs_df_h (guestfs_h *g);
This command runs the "df -h" command to report disk space used in
human-readable format.
This command is mostly useful for interactive sessions. It is
not
intended that you try to parse the output string. Use
"guestfs_statvfs" from programs.
This function returns a string, or NULL on error.
The caller must free the
returned string after use.
(Added in 1.0.54)
guestfs_dmesg¶
char *
guestfs_dmesg (guestfs_h *g);
This returns the kernel messages ("dmesg" output) from the guest
kernel. This is sometimes useful for extended debugging of problems.
Another way to get the same information is to enable verbose messages with
"guestfs_set_verbose" or by setting the environment variable
"LIBGUESTFS_DEBUG=1" before running the program.
This function returns a string, or NULL on error.
The caller must free the
returned string after use.
(Added in 1.0.18)
guestfs_download¶
int
guestfs_download (guestfs_h *g,
const char *remotefilename,
const char *filename);
Download file "remotefilename" and save it as "filename" on
the local machine.
"filename" can also be a named pipe.
See also "guestfs_upload", "guestfs_cat".
This function returns 0 on success or -1 on error.
This long-running command can generate progress notification messages so that
the caller can display a progress bar or indicator. To receive these messages,
the caller must register a progress event callback. See
"GUESTFS_EVENT_PROGRESS" in
guestfs(3).
(Added in 1.0.2)
guestfs_download_offset¶
int
guestfs_download_offset (guestfs_h *g,
const char *remotefilename,
const char *filename,
int64_t offset,
int64_t size);
Download file "remotefilename" and save it as "filename" on
the local machine.
"remotefilename" is read for "size" bytes starting at
"offset" (this region must be within the file or device).
Note that there is no limit on the amount of data that can be downloaded with
this call, unlike with "guestfs_pread", and this call always reads
the full amount unless an error occurs.
See also "guestfs_download", "guestfs_pread".
This function returns 0 on success or -1 on error.
This long-running command can generate progress notification messages so that
the caller can display a progress bar or indicator. To receive these messages,
the caller must register a progress event callback. See
"GUESTFS_EVENT_PROGRESS" in
guestfs(3).
(Added in 1.5.17)
guestfs_drop_caches¶
int
guestfs_drop_caches (guestfs_h *g,
int whattodrop);
This instructs the guest kernel to drop its page cache, and/or dentries and
inode caches. The parameter "whattodrop" tells the kernel what
precisely to drop, see
http://linux-mm.org/Drop_Caches
<
http://linux-mm.org/Drop_Caches>
Setting "whattodrop" to 3 should drop everything.
This automatically calls
sync(2) before the operation, so that the
maximum guest memory is freed.
This function returns 0 on success or -1 on error.
(Added in 1.0.18)
guestfs_du¶
int64_t
guestfs_du (guestfs_h *g,
const char *path);
This command runs the "du -s" command to estimate file space usage for
"path".
"path" can be a file or a directory. If "path" is a
directory then the estimate includes the contents of the directory and all
subdirectories (recursively).
The result is the estimated size in
kilobytes (ie. units of 1024 bytes).
On error this function returns -1.
This long-running command can generate progress notification messages so that
the caller can display a progress bar or indicator. To receive these messages,
the caller must register a progress event callback. See
"GUESTFS_EVENT_PROGRESS" in
guestfs(3).
(Added in 1.0.54)
guestfs_e2fsck¶
int
guestfs_e2fsck (guestfs_h *g,
const char *device,
...);
You may supply a list of optional arguments to this call. Use zero or more of
the following pairs of parameters, and terminate the list with "-1"
on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_E2FSCK_CORRECT, int correct,
GUESTFS_E2FSCK_FORCEALL, int forceall,
This runs the ext2/ext3 filesystem checker on "device". It can take
the following optional arguments:
- "correct"
- Automatically repair the file system. This option will
cause e2fsck to automatically fix any filesystem problems that can be
safely fixed without human intervention.
This option may not be specified at the same time as the
"forceall" option.
- "forceall"
- Assume an answer of 'yes' to all questions; allows e2fsck
to be used non-interactively.
This option may not be specified at the same time as the "correct"
option.
This function returns 0 on success or -1 on error.
(Added in 1.15.17)
guestfs_e2fsck_va¶
int
guestfs_e2fsck_va (guestfs_h *g,
const char *device,
va_list args);
This is the "va_list variant" of "guestfs_e2fsck".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_e2fsck_argv¶
int
guestfs_e2fsck_argv (guestfs_h *g,
const char *device,
const struct guestfs_e2fsck_argv *optargs);
This is the "argv variant" of "guestfs_e2fsck".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_e2fsck_f¶
int
guestfs_e2fsck_f (guestfs_h *g,
const char *device);
This function is deprecated. In new code, use the
"guestfs_e2fsck" call instead.
Deprecated functions will not be removed from the API, but the fact that they
are deprecated indicates that there are problems with correct use of these
functions.
This runs "e2fsck -p -f device", ie. runs the ext2/ext3 filesystem
checker on "device", noninteractively (
-p), even if the
filesystem appears to be clean (
-f).
This function returns 0 on success or -1 on error.
(Added in 1.0.29)
guestfs_echo_daemon¶
char *
guestfs_echo_daemon (guestfs_h *g,
char *const *words);
This command concatenates the list of "words" passed with single
spaces between them and returns the resulting string.
You can use this command to test the connection through to the daemon.
See also "guestfs_ping_daemon".
This function returns a string, or NULL on error.
The caller must free the
returned string after use.
(Added in 1.0.69)
guestfs_egrep¶
char **
guestfs_egrep (guestfs_h *g,
const char *regex,
const char *path);
This calls the external "egrep" program and returns the matching
lines.
This function returns a NULL-terminated array of strings (like
environ(3)), or NULL if there was an error.
The caller must free the
strings and the array after use.
Because of the message protocol, there is a transfer limit of somewhere between
2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
(Added in 1.0.66)
guestfs_egrepi¶
char **
guestfs_egrepi (guestfs_h *g,
const char *regex,
const char *path);
This calls the external "egrep -i" program and returns the matching
lines.
This function returns a NULL-terminated array of strings (like
environ(3)), or NULL if there was an error.
The caller must free the
strings and the array after use.
Because of the message protocol, there is a transfer limit of somewhere between
2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
(Added in 1.0.66)
guestfs_equal¶
int
guestfs_equal (guestfs_h *g,
const char *file1,
const char *file2);
This compares the two files "file1" and "file2" and returns
true if their content is exactly equal, or false otherwise.
The external
cmp(1) program is used for the comparison.
This function returns a C truth value on success or -1 on error.
(Added in 1.0.18)
guestfs_exists¶
int
guestfs_exists (guestfs_h *g,
const char *path);
This returns "true" if and only if there is a file, directory (or
anything) with the given "path" name.
See also "guestfs_is_file", "guestfs_is_dir",
"guestfs_stat".
This function returns a C truth value on success or -1 on error.
(Added in 0.8)
guestfs_fallocate¶
int
guestfs_fallocate (guestfs_h *g,
const char *path,
int len);
This function is deprecated. In new code, use the
"guestfs_fallocate64" call instead.
Deprecated functions will not be removed from the API, but the fact that they
are deprecated indicates that there are problems with correct use of these
functions.
This command preallocates a file (containing zero bytes) named "path"
of size "len" bytes. If the file exists already, it is overwritten.
Do not confuse this with the guestfish-specific "alloc" command which
allocates a file in the host and attaches it as a device.
This function returns 0 on success or -1 on error.
(Added in 1.0.66)
guestfs_fallocate64¶
int
guestfs_fallocate64 (guestfs_h *g,
const char *path,
int64_t len);
This command preallocates a file (containing zero bytes) named "path"
of size "len" bytes. If the file exists already, it is overwritten.
Note that this call allocates disk blocks for the file. To create a sparse file
use "guestfs_truncate_size" instead.
The deprecated call "guestfs_fallocate" does the same, but owing to an
oversight it only allowed 30 bit lengths to be specified, effectively limiting
the maximum size of files created through that call to 1GB.
Do not confuse this with the guestfish-specific "alloc" and
"sparse" commands which create a file in the host and attach it as a
device.
This function returns 0 on success or -1 on error.
(Added in 1.3.17)
guestfs_fgrep¶
char **
guestfs_fgrep (guestfs_h *g,
const char *pattern,
const char *path);
This calls the external "fgrep" program and returns the matching
lines.
This function returns a NULL-terminated array of strings (like
environ(3)), or NULL if there was an error.
The caller must free the
strings and the array after use.
Because of the message protocol, there is a transfer limit of somewhere between
2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
(Added in 1.0.66)
guestfs_fgrepi¶
char **
guestfs_fgrepi (guestfs_h *g,
const char *pattern,
const char *path);
This calls the external "fgrep -i" program and returns the matching
lines.
This function returns a NULL-terminated array of strings (like
environ(3)), or NULL if there was an error.
The caller must free the
strings and the array after use.
Because of the message protocol, there is a transfer limit of somewhere between
2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
(Added in 1.0.66)
guestfs_file¶
char *
guestfs_file (guestfs_h *g,
const char *path);
This call uses the standard
file(1) command to determine the type or
contents of the file.
This call will also transparently look inside various types of compressed file.
The exact command which runs is "file -zb path". Note in particular
that the filename is not prepended to the output (the
-b option).
The output depends on the output of the underlying
file(1) command and it
can change in future in ways beyond our control. In other words, the output is
not guaranteed by the ABI.
See also:
file(1), "guestfs_vfs_type",
"guestfs_lstat", "guestfs_is_file",
"guestfs_is_blockdev" (etc), "guestfs_is_zero".
This function returns a string, or NULL on error.
The caller must free the
returned string after use.
(Added in 0.9.1)
guestfs_file_architecture¶
char *
guestfs_file_architecture (guestfs_h *g,
const char *filename);
This detects the architecture of the binary "filename", and returns it
if known.
Currently defined architectures are:
- "i386"
- This string is returned for all 32 bit i386, i486, i586,
i686 binaries irrespective of the precise processor requirements of the
binary.
- "x86_64"
- 64 bit x86-64.
- "sparc"
- 32 bit SPARC.
- "sparc64"
- 64 bit SPARC V9 and above.
- "ia64"
- Intel Itanium.
- "ppc"
- 32 bit Power PC.
- "ppc64"
- 64 bit Power PC.
Libguestfs may return other architecture strings in future.
The function works on at least the following types of files:
- •
- many types of Un*x and Linux binary
- •
- many types of Un*x and Linux shared library
- •
- Windows Win32 and Win64 binaries
- •
- Windows Win32 and Win64 DLLs
Win32 binaries and DLLs return "i386".
Win64 binaries and DLLs return "x86_64".
- •
- Linux kernel modules
- •
- Linux new-style initrd images
- •
- some non-x86 Linux vmlinuz kernels
What it can't do currently:
- •
- static libraries (libfoo.a)
- •
- Linux old-style initrd as compressed ext2 filesystem (RHEL
3)
- •
- x86 Linux vmlinuz kernels
x86 vmlinuz images (bzImage format) consist of a mix of 16-, 32- and
compressed code, and are horribly hard to unpack. If you want to find the
architecture of a kernel, use the architecture of the associated initrd or
kernel module(s) instead.
This function returns a string, or NULL on error.
The caller must free the
returned string after use.
(Added in 1.5.3)
guestfs_filesize¶
int64_t
guestfs_filesize (guestfs_h *g,
const char *file);
This command returns the size of "file" in bytes.
To get other stats about a file, use "guestfs_stat",
"guestfs_lstat", "guestfs_is_dir",
"guestfs_is_file" etc. To get the size of block devices, use
"guestfs_blockdev_getsize64".
On error this function returns -1.
(Added in 1.0.82)
guestfs_fill¶
int
guestfs_fill (guestfs_h *g,
int c,
int len,
const char *path);
This command creates a new file called "path". The initial content of
the file is "len" octets of "c", where "c" must
be a number in the range "[0..255]".
To fill a file with zero bytes (sparsely), it is much more efficient to use
"guestfs_truncate_size". To create a file with a pattern of
repeating bytes use "guestfs_fill_pattern".
This function returns 0 on success or -1 on error.
This long-running command can generate progress notification messages so that
the caller can display a progress bar or indicator. To receive these messages,
the caller must register a progress event callback. See
"GUESTFS_EVENT_PROGRESS" in
guestfs(3).
(Added in 1.0.79)
guestfs_fill_pattern¶
int
guestfs_fill_pattern (guestfs_h *g,
const char *pattern,
int len,
const char *path);
This function is like "guestfs_fill" except that it creates a new file
of length "len" containing the repeating pattern of bytes in
"pattern". The pattern is truncated if necessary to ensure the
length of the file is exactly "len" bytes.
This function returns 0 on success or -1 on error.
This long-running command can generate progress notification messages so that
the caller can display a progress bar or indicator. To receive these messages,
the caller must register a progress event callback. See
"GUESTFS_EVENT_PROGRESS" in
guestfs(3).
(Added in 1.3.12)
guestfs_find¶
char **
guestfs_find (guestfs_h *g,
const char *directory);
This command lists out all files and directories, recursively, starting at
"directory". It is essentially equivalent to running the shell
command "find directory -print" but some post-processing happens on
the output, described below.
This returns a list of strings
without any prefix. Thus if the directory
structure was:
/tmp/a
/tmp/b
/tmp/c/d
then the returned list from "guestfs_find" "/tmp" would be 4
elements:
a
b
c
c/d
If "directory" is not a directory, then this command returns an error.
The returned list is sorted.
See also "guestfs_find0".
This function returns a NULL-terminated array of strings (like
environ(3)), or NULL if there was an error.
The caller must free the
strings and the array after use.
Because of the message protocol, there is a transfer limit of somewhere between
2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
(Added in 1.0.27)
guestfs_find0¶
int
guestfs_find0 (guestfs_h *g,
const char *directory,
const char *files);
This command lists out all files and directories, recursively, starting at
"directory", placing the resulting list in the external file called
"files".
This command works the same way as "guestfs_find" with the following
exceptions:
- •
- The resulting list is written to an external file.
- •
- Items (filenames) in the result are separated by
"\0" characters. See find(1) option -print0.
- •
- This command is not limited in the number of names that it
can return.
- •
- The result list is not sorted.
This function returns 0 on success or -1 on error.
(Added in 1.0.74)
guestfs_findfs_label¶
char *
guestfs_findfs_label (guestfs_h *g,
const char *label);
This command searches the filesystems and returns the one which has the given
label. An error is returned if no such filesystem can be found.
To find the label of a filesystem, use "guestfs_vfs_label".
This function returns a string, or NULL on error.
The caller must free the
returned string after use.
(Added in 1.5.3)
guestfs_findfs_uuid¶
char *
guestfs_findfs_uuid (guestfs_h *g,
const char *uuid);
This command searches the filesystems and returns the one which has the given
UUID. An error is returned if no such filesystem can be found.
To find the UUID of a filesystem, use "guestfs_vfs_uuid".
This function returns a string, or NULL on error.
The caller must free the
returned string after use.
(Added in 1.5.3)
guestfs_fsck¶
int
guestfs_fsck (guestfs_h *g,
const char *fstype,
const char *device);
This runs the filesystem checker (fsck) on "device" which should have
filesystem type "fstype".
The returned integer is the status. See
fsck(8) for the list of status
codes from "fsck".
Notes:
- •
- Multiple status codes can be summed together.
- •
- A non-zero return code can mean "success", for
example if errors have been corrected on the filesystem.
- •
- Checking or repairing NTFS volumes is not supported (by
linux-ntfs).
This command is entirely equivalent to running "fsck -a -t fstype
device".
On error this function returns -1.
(Added in 1.0.16)
guestfs_get_append¶
const char *
guestfs_get_append (guestfs_h *g);
Return the additional kernel options which are added to the guest kernel command
line.
If "NULL" then no options are added.
This function returns a string which may be NULL. There is no way to return an
error from this function. The string is owned by the guest handle and must
not be freed.
(Added in 1.0.26)
guestfs_get_attach_method¶
char *
guestfs_get_attach_method (guestfs_h *g);
Return the current attach method. See "guestfs_set_attach_method".
This function returns a string, or NULL on error.
The caller must free the
returned string after use.
(Added in 1.9.8)
guestfs_get_autosync¶
int
guestfs_get_autosync (guestfs_h *g);
Get the autosync flag.
This function returns a C truth value on success or -1 on error.
(Added in 0.3)
guestfs_get_direct¶
int
guestfs_get_direct (guestfs_h *g);
Return the direct appliance mode flag.
This function returns a C truth value on success or -1 on error.
(Added in 1.0.72)
guestfs_get_e2attrs¶
char *
guestfs_get_e2attrs (guestfs_h *g,
const char *file);
This returns the file attributes associated with "file".
The attributes are a set of bits associated with each inode which affect the
behaviour of the file. The attributes are returned as a string of letters
(described below). The string may be empty, indicating that no file attributes
are set for this file.
These attributes are only present when the file is located on an ext2/3/4
filesystem. Using this call on other filesystem types will result in an error.
The characters (file attributes) in the returned string are currently:
- 'A'
- When the file is accessed, its atime is not modified.
- 'a'
- The file is append-only.
- 'c'
- The file is compressed on-disk.
- 'D'
- (Directories only.) Changes to this directory are written
synchronously to disk.
- 'd'
- The file is not a candidate for backup (see
dump(8)).
- 'E'
- The file has compression errors.
- 'e'
- The file is using extents.
- 'h'
- The file is storing its blocks in units of the filesystem
blocksize instead of sectors.
- 'I'
- (Directories only.) The directory is using hashed
trees.
- 'i'
- The file is immutable. It cannot be modified, deleted or
renamed. No link can be created to this file.
- 'j'
- The file is data-journaled.
- 's'
- When the file is deleted, all its blocks will be
zeroed.
- 'S'
- Changes to this file are written synchronously to
disk.
- 'T'
- (Directories only.) This is a hint to the block allocator
that subdirectories contained in this directory should be spread across
blocks. If not present, the block allocator will try to group
subdirectories together.
- 't'
- For a file, this disables tail-merging. (Not used by
upstream implementations of ext2.)
- 'u'
- When the file is deleted, its blocks will be saved,
allowing the file to be undeleted.
- 'X'
- The raw contents of the compressed file may be
accessed.
- 'Z'
- The compressed file is dirty.
More file attributes may be added to this list later. Not all file attributes
may be set for all kinds of files. For detailed information, consult the
chattr(1) man page.
See also "guestfs_set_e2attrs".
Don't confuse these attributes with extended attributes (see
"guestfs_getxattr").
This function returns a string, or NULL on error.
The caller must free the
returned string after use.
(Added in 1.17.31)
guestfs_get_e2generation¶
int64_t
guestfs_get_e2generation (guestfs_h *g,
const char *file);
This returns the ext2 file generation of a file. The generation (which used to
be called the "version") is a number associated with an inode. This
is most commonly used by NFS servers.
The generation is only present when the file is located on an ext2/3/4
filesystem. Using this call on other filesystem types will result in an error.
See "guestfs_set_e2generation".
On error this function returns -1.
(Added in 1.17.31)
guestfs_get_e2label¶
char *
guestfs_get_e2label (guestfs_h *g,
const char *device);
This function is deprecated. In new code, use the
"guestfs_vfs_label" call instead.
Deprecated functions will not be removed from the API, but the fact that they
are deprecated indicates that there are problems with correct use of these
functions.
This returns the ext2/3/4 filesystem label of the filesystem on
"device".
This function returns a string, or NULL on error.
The caller must free the
returned string after use.
(Added in 1.0.15)
guestfs_get_e2uuid¶
char *
guestfs_get_e2uuid (guestfs_h *g,
const char *device);
This function is deprecated. In new code, use the
"guestfs_vfs_uuid" call instead.
Deprecated functions will not be removed from the API, but the fact that they
are deprecated indicates that there are problems with correct use of these
functions.
This returns the ext2/3/4 filesystem UUID of the filesystem on
"device".
This function returns a string, or NULL on error.
The caller must free the
returned string after use.
(Added in 1.0.15)
guestfs_get_memsize¶
int
guestfs_get_memsize (guestfs_h *g);
This gets the memory size in megabytes allocated to the qemu subprocess.
If "guestfs_set_memsize" was not called on this handle, and if
"LIBGUESTFS_MEMSIZE" was not set, then this returns the compiled-in
default value for memsize.
For more information on the architecture of libguestfs, see
guestfs(3).
On error this function returns -1.
(Added in 1.0.55)
guestfs_get_network¶
int
guestfs_get_network (guestfs_h *g);
This returns the enable network flag.
This function returns a C truth value on success or -1 on error.
(Added in 1.5.4)
guestfs_get_path¶
const char *
guestfs_get_path (guestfs_h *g);
Return the current search path.
This is always non-NULL. If it wasn't set already, then this will return the
default path.
This function returns a string, or NULL on error. The string is owned by the
guest handle and must
not be freed.
(Added in 0.3)
guestfs_get_pgroup¶
int
guestfs_get_pgroup (guestfs_h *g);
This returns the process group flag.
This function returns a C truth value on success or -1 on error.
(Added in 1.11.18)
guestfs_get_pid¶
int
guestfs_get_pid (guestfs_h *g);
Return the process ID of the qemu subprocess. If there is no qemu subprocess,
then this will return an error.
This is an internal call used for debugging and testing.
On error this function returns -1.
(Added in 1.0.56)
guestfs_get_qemu¶
const char *
guestfs_get_qemu (guestfs_h *g);
Return the current qemu binary.
This is always non-NULL. If it wasn't set already, then this will return the
default qemu binary name.
This function returns a string, or NULL on error. The string is owned by the
guest handle and must
not be freed.
(Added in 1.0.6)
guestfs_get_recovery_proc¶
int
guestfs_get_recovery_proc (guestfs_h *g);
Return the recovery process enabled flag.
This function returns a C truth value on success or -1 on error.
(Added in 1.0.77)
guestfs_get_selinux¶
int
guestfs_get_selinux (guestfs_h *g);
This returns the current setting of the selinux flag which is passed to the
appliance at boot time. See "guestfs_set_selinux".
For more information on the architecture of libguestfs, see
guestfs(3).
This function returns a C truth value on success or -1 on error.
(Added in 1.0.67)
guestfs_get_smp¶
int
guestfs_get_smp (guestfs_h *g);
This returns the number of virtual CPUs assigned to the appliance.
On error this function returns -1.
(Added in 1.13.15)
guestfs_get_state¶
int
guestfs_get_state (guestfs_h *g);
This returns the current state as an opaque integer. This is only useful for
printing debug and internal error messages.
For more information on states, see
guestfs(3).
On error this function returns -1.
(Added in 1.0.2)
guestfs_get_trace¶
int
guestfs_get_trace (guestfs_h *g);
Return the command trace flag.
This function returns a C truth value on success or -1 on error.
(Added in 1.0.69)
guestfs_get_umask¶
int
guestfs_get_umask (guestfs_h *g);
Return the current umask. By default the umask is 022 unless it has been set by
calling "guestfs_umask".
On error this function returns -1.
(Added in 1.3.4)
guestfs_get_verbose¶
int
guestfs_get_verbose (guestfs_h *g);
This returns the verbose messages flag.
This function returns a C truth value on success or -1 on error.
(Added in 0.3)
guestfs_getcon¶
char *
guestfs_getcon (guestfs_h *g);
This gets the SELinux security context of the daemon.
See the documentation about SELINUX in
guestfs(3), and
"guestfs_setcon"
This function returns a string, or NULL on error.
The caller must free the
returned string after use.
(Added in 1.0.67)
guestfs_getxattr¶
char *
guestfs_getxattr (guestfs_h *g,
const char *path,
const char *name,
size_t *size_r);
Get a single extended attribute from file "path" named
"name". This call follows symlinks. If you want to lookup an
extended attribute for the symlink itself, use "guestfs_lgetxattr".
Normally it is better to get all extended attributes from a file in one go by
calling "guestfs_getxattrs". However some Linux filesystem
implementations are buggy and do not provide a way to list out attributes. For
these filesystems (notably ntfs-3g) you have to know the names of the extended
attributes you want in advance and call this function.
Extended attribute values are blobs of binary data. If there is no extended
attribute named "name", this returns an error.
See also: "guestfs_getxattrs", "guestfs_lgetxattr",
attr(5).
This function returns a buffer, or NULL on error. The size of the returned
buffer is written to *size_r.
The caller must free the returned buffer
after use.
(Added in 1.7.24)
guestfs_getxattrs¶
struct guestfs_xattr_list *
guestfs_getxattrs (guestfs_h *g,
const char *path);
This call lists the extended attributes of the file or directory
"path".
At the system call level, this is a combination of the
listxattr(2) and
getxattr(2) calls.
See also: "guestfs_lgetxattrs",
attr(5).
This function returns a "struct guestfs_xattr_list *", or NULL if
there was an error.
The caller must call
"guestfs_free_xattr_list" after use.
(Added in 1.0.59)
guestfs_glob_expand¶
char **
guestfs_glob_expand (guestfs_h *g,
const char *pattern);
This command searches for all the pathnames matching "pattern"
according to the wildcard expansion rules used by the shell.
If no paths match, then this returns an empty list (note: not an error).
It is just a wrapper around the C
glob(3) function with flags
"GLOB_MARK|GLOB_BRACE". See that manual page for more details.
Notice that there is no equivalent command for expanding a device name (eg.
"/dev/sd*"). Use "guestfs_list_devices",
"guestfs_list_partitions" etc functions instead.
This function returns a NULL-terminated array of strings (like
environ(3)), or NULL if there was an error.
The caller must free the
strings and the array after use.
(Added in 1.0.50)
guestfs_grep¶
char **
guestfs_grep (guestfs_h *g,
const char *regex,
const char *path);
This calls the external "grep" program and returns the matching lines.
This function returns a NULL-terminated array of strings (like
environ(3)), or NULL if there was an error.
The caller must free the
strings and the array after use.
Because of the message protocol, there is a transfer limit of somewhere between
2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
(Added in 1.0.66)
guestfs_grepi¶
char **
guestfs_grepi (guestfs_h *g,
const char *regex,
const char *path);
This calls the external "grep -i" program and returns the matching
lines.
This function returns a NULL-terminated array of strings (like
environ(3)), or NULL if there was an error.
The caller must free the
strings and the array after use.
Because of the message protocol, there is a transfer limit of somewhere between
2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
(Added in 1.0.66)
guestfs_grub_install¶
int
guestfs_grub_install (guestfs_h *g,
const char *root,
const char *device);
This command installs GRUB 1 (the Grand Unified Bootloader) on
"device", with the root directory being "root".
Notes:
- •
- There is currently no way in the API to install grub2,
which is used by most modern Linux guests. It is possible to run the grub2
command from the guest, although see the caveats in "RUNNING
COMMANDS" in guestfs(3).
- •
- This uses "grub-install" from the host.
Unfortunately grub is not always compatible with itself, so this only
works in rather narrow circumstances. Careful testing with each guest
version is advisable.
- •
- If grub-install reports the error "No suitable drive
was found in the generated device map." it may be that you need to
create a "/boot/grub/device.map" file first that contains the
mapping between grub device names and Linux device names. It is usually
sufficient to create a file containing:
(hd0) /dev/vda
replacing "/dev/vda" with the name of the installation
device.
This function returns 0 on success or -1 on error.
(Added in 1.0.17)
guestfs_head¶
char **
guestfs_head (guestfs_h *g,
const char *path);
This command returns up to the first 10 lines of a file as a list of strings.
This function returns a NULL-terminated array of strings (like
environ(3)), or NULL if there was an error.
The caller must free the
strings and the array after use.
Because of the message protocol, there is a transfer limit of somewhere between
2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
(Added in 1.0.54)
guestfs_head_n¶
char **
guestfs_head_n (guestfs_h *g,
int nrlines,
const char *path);
If the parameter "nrlines" is a positive number, this returns the
first "nrlines" lines of the file "path".
If the parameter "nrlines" is a negative number, this returns lines
from the file "path", excluding the last "nrlines" lines.
If the parameter "nrlines" is zero, this returns an empty list.
This function returns a NULL-terminated array of strings (like
environ(3)), or NULL if there was an error.
The caller must free the
strings and the array after use.
Because of the message protocol, there is a transfer limit of somewhere between
2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
(Added in 1.0.54)
guestfs_hexdump¶
char *
guestfs_hexdump (guestfs_h *g,
const char *path);
This runs "hexdump -C" on the given "path". The result is
the human-readable, canonical hex dump of the file.
This function returns a string, or NULL on error.
The caller must free the
returned string after use.
Because of the message protocol, there is a transfer limit of somewhere between
2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
(Added in 1.0.22)
guestfs_initrd_cat¶
char *
guestfs_initrd_cat (guestfs_h *g,
const char *initrdpath,
const char *filename,
size_t *size_r);
This command unpacks the file "filename" from the initrd file called
"initrdpath". The filename must be given
without the initial
"/" character.
For example, in guestfish you could use the following command to examine the
boot script (usually called "/init") contained in a Linux initrd or
initramfs image:
initrd-cat /boot/initrd-<version>.img init
See also "guestfs_initrd_list".
This function returns a buffer, or NULL on error. The size of the returned
buffer is written to *size_r.
The caller must free the returned buffer
after use.
Because of the message protocol, there is a transfer limit of somewhere between
2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
(Added in 1.0.84)
guestfs_initrd_list¶
char **
guestfs_initrd_list (guestfs_h *g,
const char *path);
This command lists out files contained in an initrd.
The files are listed without any initial "/" character. The files are
listed in the order they appear (not necessarily alphabetical). Directory
names are listed as separate items.
Old Linux kernels (2.4 and earlier) used a compressed ext2 filesystem as initrd.
We
only support the newer initramfs format (compressed cpio files).
This function returns a NULL-terminated array of strings (like
environ(3)), or NULL if there was an error.
The caller must free the
strings and the array after use.
(Added in 1.0.54)
guestfs_inotify_add_watch¶
int64_t
guestfs_inotify_add_watch (guestfs_h *g,
const char *path,
int mask);
Watch "path" for the events listed in "mask".
Note that if "path" is a directory then events within that directory
are watched, but this does
not happen recursively (in subdirectories).
Note for non-C or non-Linux callers: the inotify events are defined by the Linux
kernel ABI and are listed in "/usr/include/sys/inotify.h".
On error this function returns -1.
(Added in 1.0.66)
guestfs_inotify_close¶
int
guestfs_inotify_close (guestfs_h *g);
This closes the inotify handle which was previously opened by inotify_init. It
removes all watches, throws away any pending events, and deallocates all
resources.
This function returns 0 on success or -1 on error.
(Added in 1.0.66)
guestfs_inotify_files¶
char **
guestfs_inotify_files (guestfs_h *g);
This function is a helpful wrapper around "guestfs_inotify_read" which
just returns a list of pathnames of objects that were touched. The returned
pathnames are sorted and deduplicated.
This function returns a NULL-terminated array of strings (like
environ(3)), or NULL if there was an error.
The caller must free the
strings and the array after use.
(Added in 1.0.66)
guestfs_inotify_init¶
int
guestfs_inotify_init (guestfs_h *g,
int maxevents);
This command creates a new inotify handle. The inotify subsystem can be used to
notify events which happen to objects in the guest filesystem.
"maxevents" is the maximum number of events which will be queued up
between calls to "guestfs_inotify_read" or
"guestfs_inotify_files". If this is passed as 0, then the kernel (or
previously set) default is used. For Linux 2.6.29 the default was 16384
events. Beyond this limit, the kernel throws away events, but records the fact
that it threw them away by setting a flag "IN_Q_OVERFLOW" in the
returned structure list (see "guestfs_inotify_read").
Before any events are generated, you have to add some watches to the internal
watch list. See: "guestfs_inotify_add_watch" and
"guestfs_inotify_rm_watch".
Queued up events should be read periodically by calling
"guestfs_inotify_read" (or "guestfs_inotify_files" which
is just a helpful wrapper around "guestfs_inotify_read"). If you
don't read the events out often enough then you risk the internal queue
overflowing.
The handle should be closed after use by calling
"guestfs_inotify_close". This also removes any watches
automatically.
See also
inotify(7) for an overview of the inotify interface as exposed
by the Linux kernel, which is roughly what we expose via libguestfs. Note that
there is one global inotify handle per libguestfs instance.
This function returns 0 on success or -1 on error.
(Added in 1.0.66)
guestfs_inotify_read¶
struct guestfs_inotify_event_list *
guestfs_inotify_read (guestfs_h *g);
Return the complete queue of events that have happened since the previous read
call.
If no events have happened, this returns an empty list.
Note: In order to make sure that all events have been read, you must call
this function repeatedly until it returns an empty list. The reason is that
the call will read events up to the maximum appliance-to-host message size and
leave remaining events in the queue.
This function returns a "struct guestfs_inotify_event_list *", or NULL
if there was an error.
The caller must call
"guestfs_free_inotify_event_list" after use.
(Added in 1.0.66)
guestfs_inotify_rm_watch¶
int
guestfs_inotify_rm_watch (guestfs_h *g,
int wd);
Remove a previously defined inotify watch. See
"guestfs_inotify_add_watch".
This function returns 0 on success or -1 on error.
(Added in 1.0.66)
guestfs_inspect_get_arch¶
char *
guestfs_inspect_get_arch (guestfs_h *g,
const char *root);
This returns the architecture of the inspected operating system. The possible
return values are listed under "guestfs_file_architecture".
If the architecture could not be determined, then the string "unknown"
is returned.
Please read "INSPECTION" in
guestfs(3) for more details.
This function returns a string, or NULL on error.
The caller must free the
returned string after use.
(Added in 1.5.3)
guestfs_inspect_get_distro¶
char *
guestfs_inspect_get_distro (guestfs_h *g,
const char *root);
This returns the distro (distribution) of the inspected operating system.
Currently defined distros are:
- "archlinux"
- Arch Linux.
- "buildroot"
- Buildroot-derived distro, but not one we specifically
recognize.
- "centos"
- CentOS.
- "cirros"
- Cirros.
- "debian"
- Debian.
- "fedora"
- Fedora.
- "freedos"
- FreeDOS.
- "gentoo"
- Gentoo.
- "linuxmint"
- Linux Mint.
- "mageia"
- Mageia.
- "mandriva"
- Mandriva.
- "meego"
- MeeGo.
- "opensuse"
- OpenSUSE.
- "pardus"
- Pardus.
- "redhat-based"
- Some Red Hat-derived distro.
- "rhel"
- Red Hat Enterprise Linux.
- "scientificlinux"
- Scientific Linux.
- "slackware"
- Slackware.
- "ttylinux"
- ttylinux.
- "ubuntu"
- Ubuntu.
- "unknown"
- The distro could not be determined.
- "windows"
- Windows does not have distributions. This string is
returned if the OS type is Windows.
Future versions of libguestfs may return other strings here. The caller should
be prepared to handle any string.
Please read "INSPECTION" in
guestfs(3) for more details.
This function returns a string, or NULL on error.
The caller must free the
returned string after use.
(Added in 1.5.3)
guestfs_inspect_get_drive_mappings¶
char **
guestfs_inspect_get_drive_mappings (guestfs_h *g,
const char *root);
This call is useful for Windows which uses a primitive system of assigning drive
letters (like "C:") to partitions. This inspection API examines the
Windows Registry to find out how disks/partitions are mapped to drive letters,
and returns a hash table as in the example below:
C => /dev/vda2
E => /dev/vdb1
F => /dev/vdc1
Note that keys are drive letters. For Windows, the key is case insensitive and
just contains the drive letter, without the customary colon separator
character.
In future we may support other operating systems that also used drive letters,
but the keys for those might not be case insensitive and might be longer than
1 character. For example in OS-9, hard drives were named "h0",
"h1" etc.
For Windows guests, currently only hard drive mappings are returned. Removable
disks (eg. DVD-ROMs) are ignored.
For guests that do not use drive mappings, or if the drive mappings could not be
determined, this returns an empty hash table.
Please read "INSPECTION" in
guestfs(3) for more details. See
also "guestfs_inspect_get_mountpoints",
"guestfs_inspect_get_filesystems".
This function returns a NULL-terminated array of strings, or NULL if there was
an error. The array of strings will always have length "2n+1", where
"n" keys and values alternate, followed by the trailing NULL entry.
The caller must free the strings and the array after use.
(Added in 1.9.17)
guestfs_inspect_get_filesystems¶
char **
guestfs_inspect_get_filesystems (guestfs_h *g,
const char *root);
This returns a list of all the filesystems that we think are associated with
this operating system. This includes the root filesystem, other ordinary
filesystems, and non-mounted devices like swap partitions.
In the case of a multi-boot virtual machine, it is possible for a filesystem to
be shared between operating systems.
Please read "INSPECTION" in
guestfs(3) for more details. See
also "guestfs_inspect_get_mountpoints".
This function returns a NULL-terminated array of strings (like
environ(3)), or NULL if there was an error.
The caller must free the
strings and the array after use.
(Added in 1.5.3)
char *
guestfs_inspect_get_format (guestfs_h *g,
const char *root);
This returns the format of the inspected operating system. You can use it to
detect install images, live CDs and similar.
Currently defined formats are:
- "installed"
- This is an installed operating system.
- "installer"
- The disk image being inspected is not an installed
operating system, but a bootable install disk, live CD, or
similar.
- "unknown"
- The format of this disk image is not known.
Future versions of libguestfs may return other strings here. The caller should
be prepared to handle any string.
Please read "INSPECTION" in
guestfs(3) for more details.
This function returns a string, or NULL on error.
The caller must free the
returned string after use.
(Added in 1.9.4)
guestfs_inspect_get_hostname¶
char *
guestfs_inspect_get_hostname (guestfs_h *g,
const char *root);
This function returns the hostname of the operating system as found by
inspection of the guest's configuration files.
If the hostname could not be determined, then the string "unknown" is
returned.
Please read "INSPECTION" in
guestfs(3) for more details.
This function returns a string, or NULL on error.
The caller must free the
returned string after use.
(Added in 1.7.9)
guestfs_inspect_get_icon¶
char *
guestfs_inspect_get_icon (guestfs_h *g,
const char *root,
size_t *size_r,
...);
You may supply a list of optional arguments to this call. Use zero or more of
the following pairs of parameters, and terminate the list with "-1"
on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_INSPECT_GET_ICON_FAVICON, int favicon,
GUESTFS_INSPECT_GET_ICON_HIGHQUALITY, int highquality,
This function returns an icon corresponding to the inspected operating system.
The icon is returned as a buffer containing a PNG image (re-encoded to PNG if
necessary).
If it was not possible to get an icon this function returns a zero-length
(non-NULL) buffer.
Callers must check for this case.
Libguestfs will start by looking for a file called "/etc/favicon.png"
or "C:\etc\favicon.png" and if it has the correct format, the
contents of this file will be returned. You can disable favicons by passing
the optional "favicon" boolean as false (default is true).
If finding the favicon fails, then we look in other places in the guest for a
suitable icon.
If the optional "highquality" boolean is true then only high quality
icons are returned, which means only icons of high resolution with an alpha
channel. The default (false) is to return any icon we can, even if it is of
substandard quality.
Notes:
- •
- Unlike most other inspection API calls, the guest's disks
must be mounted up before you call this, since it needs to read
information from the guest filesystem during the call.
- •
- Security: The icon data comes from the untrusted
guest, and should be treated with caution. PNG files have been known to
contain exploits. Ensure that libpng (or other relevant libraries) are
fully up to date before trying to process or display the icon.
- •
- The PNG image returned can be any size. It might not be
square. Libguestfs tries to return the largest, highest quality icon
available. The application must scale the icon to the required size.
- •
- Extracting icons from Windows guests requires the external
"wrestool" program from the "icoutils" package, and
several programs ("bmptopnm", "pnmtopng",
"pamcut") from the "netpbm" package. These must be
installed separately.
- •
- Operating system icons are usually trademarks. Seek legal
advice before using trademarks in applications.
This function returns a buffer, or NULL on error. The size of the returned
buffer is written to *size_r.
The caller must free the returned buffer
after use.
(Added in 1.11.12)
guestfs_inspect_get_icon_va¶
char *
guestfs_inspect_get_icon_va (guestfs_h *g,
const char *root,
size_t *size_r,
va_list args);
This is the "va_list variant" of "guestfs_inspect_get_icon".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_inspect_get_icon_argv¶
char *
guestfs_inspect_get_icon_argv (guestfs_h *g,
const char *root,
size_t *size_r,
const struct guestfs_inspect_get_icon_argv *optargs);
This is the "argv variant" of "guestfs_inspect_get_icon".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_inspect_get_major_version¶
int
guestfs_inspect_get_major_version (guestfs_h *g,
const char *root);
This returns the major version number of the inspected operating system.
Windows uses a consistent versioning scheme which is
not reflected in the
popular public names used by the operating system. Notably the operating
system known as "Windows 7" is really version 6.1 (ie. major = 6,
minor = 1). You can find out the real versions corresponding to releases of
Windows by consulting Wikipedia or MSDN.
If the version could not be determined, then 0 is returned.
Please read "INSPECTION" in
guestfs(3) for more details.
On error this function returns -1.
(Added in 1.5.3)
guestfs_inspect_get_minor_version¶
int
guestfs_inspect_get_minor_version (guestfs_h *g,
const char *root);
This returns the minor version number of the inspected operating system.
If the version could not be determined, then 0 is returned.
Please read "INSPECTION" in
guestfs(3) for more details. See
also "guestfs_inspect_get_major_version".
On error this function returns -1.
(Added in 1.5.3)
guestfs_inspect_get_mountpoints¶
char **
guestfs_inspect_get_mountpoints (guestfs_h *g,
const char *root);
This returns a hash of where we think the filesystems associated with this
operating system should be mounted. Callers should note that this is at best
an educated guess made by reading configuration files such as
"/etc/fstab".
In particular note that this may return
filesystems which are non-existent or not mountable and callers should be
prepared to handle or ignore failures if they try to mount them.
Each element in the returned hashtable has a key which is the path of the
mountpoint (eg. "/boot") and a value which is the filesystem that
would be mounted there (eg. "/dev/sda1").
Non-mounted devices such as swap devices are
not returned in this list.
For operating systems like Windows which still use drive letters, this call will
only return an entry for the first drive "mounted on" "/".
For information about the mapping of drive letters to partitions, see
"guestfs_inspect_get_drive_mappings".
Please read "INSPECTION" in
guestfs(3) for more details. See
also "guestfs_inspect_get_filesystems".
This function returns a NULL-terminated array of strings, or NULL if there was
an error. The array of strings will always have length "2n+1", where
"n" keys and values alternate, followed by the trailing NULL entry.
The caller must free the strings and the array after use.
(Added in 1.5.3)
char *
guestfs_inspect_get_package_format (guestfs_h *g,
const char *root);
This function and "guestfs_inspect_get_package_management" return the
package format and package management tool used by the inspected operating
system. For example for Fedora these functions would return "rpm"
(package format) and "yum" (package management).
This returns the string "unknown" if we could not determine the
package format
or if the operating system does not have a real
packaging system (eg. Windows).
Possible strings include: "rpm", "deb", "ebuild",
"pisi", "pacman", "pkgsrc". Future versions of
libguestfs may return other strings.
Please read "INSPECTION" in
guestfs(3) for more details.
This function returns a string, or NULL on error.
The caller must free the
returned string after use.
(Added in 1.7.5)
guestfs_inspect_get_package_management¶
char *
guestfs_inspect_get_package_management (guestfs_h *g,
const char *root);
"guestfs_inspect_get_package_format" and this function return the
package format and package management tool used by the inspected operating
system. For example for Fedora these functions would return "rpm"
(package format) and "yum" (package management).
This returns the string "unknown" if we could not determine the
package management tool
or if the operating system does not have a real
packaging system (eg. Windows).
Possible strings include: "yum", "up2date", "apt"
(for all Debian derivatives), "portage", "pisi",
"pacman", "urpmi", "zypper". Future versions of
libguestfs may return other strings.
Please read "INSPECTION" in
guestfs(3) for more details.
This function returns a string, or NULL on error.
The caller must free the
returned string after use.
(Added in 1.7.5)
guestfs_inspect_get_product_name¶
char *
guestfs_inspect_get_product_name (guestfs_h *g,
const char *root);
This returns the product name of the inspected operating system. The product
name is generally some freeform string which can be displayed to the user, but
should not be parsed by programs.
If the product name could not be determined, then the string "unknown"
is returned.
Please read "INSPECTION" in
guestfs(3) for more details.
This function returns a string, or NULL on error.
The caller must free the
returned string after use.
(Added in 1.5.3)
guestfs_inspect_get_product_variant¶
char *
guestfs_inspect_get_product_variant (guestfs_h *g,
const char *root);
This returns the product variant of the inspected operating system.
For Windows guests, this returns the contents of the Registry key
"HKLM\Software\Microsoft\Windows NT\CurrentVersion"
"InstallationType" which is usually a string such as
"Client" or "Server" (other values are possible). This can
be used to distinguish consumer and enterprise versions of Windows that have
the same version number (for example, Windows 7 and Windows 2008 Server are
both version 6.1, but the former is "Client" and the latter is
"Server").
For enterprise Linux guests, in future we intend this to return the product
variant such as "Desktop", "Server" and so on. But this is
not implemented at present.
If the product variant could not be determined, then the string
"unknown" is returned.
Please read "INSPECTION" in
guestfs(3) for more details. See
also "guestfs_inspect_get_product_name",
"guestfs_inspect_get_major_version".
This function returns a string, or NULL on error.
The caller must free the
returned string after use.
(Added in 1.9.13)
guestfs_inspect_get_roots¶
char **
guestfs_inspect_get_roots (guestfs_h *g);
This function is a convenient way to get the list of root devices, as returned
from a previous call to "guestfs_inspect_os", but without redoing
the whole inspection process.
This returns an empty list if either no root devices were found or the caller
has not called "guestfs_inspect_os".
Please read "INSPECTION" in
guestfs(3) for more details.
This function returns a NULL-terminated array of strings (like
environ(3)), or NULL if there was an error.
The caller must free the
strings and the array after use.
(Added in 1.7.3)
guestfs_inspect_get_type¶
char *
guestfs_inspect_get_type (guestfs_h *g,
const char *root);
This returns the type of the inspected operating system. Currently defined types
are:
- "linux"
- Any Linux-based operating system.
- "windows"
- Any Microsoft Windows operating system.
- "freebsd"
- FreeBSD.
- "netbsd"
- NetBSD.
- "hurd"
- GNU/Hurd.
- "dos"
- MS-DOS, FreeDOS and others.
- "unknown"
- The operating system type could not be determined.
Future versions of libguestfs may return other strings here. The caller should
be prepared to handle any string.
Please read "INSPECTION" in
guestfs(3) for more details.
This function returns a string, or NULL on error.
The caller must free the
returned string after use.
(Added in 1.5.3)
guestfs_inspect_get_windows_current_control_set¶
char *
guestfs_inspect_get_windows_current_control_set (guestfs_h *g,
const char *root);
This returns the Windows CurrentControlSet of the inspected guest. The
CurrentControlSet is a registry key name such as "ControlSet001".
This call assumes that the guest is Windows and that the Registry could be
examined by inspection. If this is not the case then an error is returned.
Please read "INSPECTION" in
guestfs(3) for more details.
This function returns a string, or NULL on error.
The caller must free the
returned string after use.
(Added in 1.9.17)
guestfs_inspect_get_windows_systemroot¶
char *
guestfs_inspect_get_windows_systemroot (guestfs_h *g,
const char *root);
This returns the Windows systemroot of the inspected guest. The systemroot is a
directory path such as "/WINDOWS".
This call assumes that the guest is Windows and that the systemroot could be
determined by inspection. If this is not the case then an error is returned.
Please read "INSPECTION" in
guestfs(3) for more details.
This function returns a string, or NULL on error.
The caller must free the
returned string after use.
(Added in 1.5.25)
guestfs_inspect_is_live¶
int
guestfs_inspect_is_live (guestfs_h *g,
const char *root);
If "guestfs_inspect_get_format" returns "installer" (this is
an install disk), then this returns true if a live image was detected on the
disk.
Please read "INSPECTION" in
guestfs(3) for more details.
This function returns a C truth value on success or -1 on error.
(Added in 1.9.4)
guestfs_inspect_is_multipart¶
int
guestfs_inspect_is_multipart (guestfs_h *g,
const char *root);
If "guestfs_inspect_get_format" returns "installer" (this is
an install disk), then this returns true if the disk is part of a set.
Please read "INSPECTION" in
guestfs(3) for more details.
This function returns a C truth value on success or -1 on error.
(Added in 1.9.4)
guestfs_inspect_is_netinst¶
int
guestfs_inspect_is_netinst (guestfs_h *g,
const char *root);
If "guestfs_inspect_get_format" returns "installer" (this is
an install disk), then this returns true if the disk is a network installer,
ie. not a self-contained install CD but one which is likely to require network
access to complete the install.
Please read "INSPECTION" in
guestfs(3) for more details.
This function returns a C truth value on success or -1 on error.
(Added in 1.9.4)
guestfs_inspect_list_applications¶
struct guestfs_application_list *
guestfs_inspect_list_applications (guestfs_h *g,
const char *root);
Return the list of applications installed in the operating system.
Note: This call works differently from other parts of the inspection API.
You have to call "guestfs_inspect_os", then
"guestfs_inspect_get_mountpoints", then mount up the disks, before
calling this. Listing applications is a significantly more difficult operation
which requires access to the full filesystem. Also note that unlike the other
"guestfs_inspect_get_*" calls which are just returning data cached
in the libguestfs handle, this call actually reads parts of the mounted
filesystems during the call.
This returns an empty list if the inspection code was not able to determine the
list of applications.
The application structure contains the following fields:
- "app_name"
- The name of the application. For Red Hat-derived and
Debian-derived Linux guests, this is the package name.
- "app_display_name"
- The display name of the application, sometimes localized to
the install language of the guest operating system.
If unavailable this is returned as an empty string "". Callers
needing to display something can use "app_name" instead.
- "app_epoch"
- For package managers which use epochs, this contains the
epoch of the package (an integer). If unavailable, this is returned as
0.
- "app_version"
- The version string of the application or package. If
unavailable this is returned as an empty string "".
- "app_release"
- The release string of the application or package, for
package managers that use this. If unavailable this is returned as an
empty string "".
- "app_install_path"
- The installation path of the application (on operating
systems such as Windows which use installation paths). This path is in the
format used by the guest operating system, it is not a libguestfs path.
If unavailable this is returned as an empty string "".
- "app_trans_path"
- The install path translated into a libguestfs path. If
unavailable this is returned as an empty string "".
- "app_publisher"
- The name of the publisher of the application, for package
managers that use this. If unavailable this is returned as an empty string
"".
- "app_url"
- The URL (eg. upstream URL) of the application. If
unavailable this is returned as an empty string "".
- "app_source_package"
- For packaging systems which support this, the name of the
source package. If unavailable this is returned as an empty string
"".
- "app_summary"
- A short (usually one line) description of the application
or package. If unavailable this is returned as an empty string
"".
- "app_description"
- A longer description of the application or package. If
unavailable this is returned as an empty string "".
Please read "INSPECTION" in
guestfs(3) for more details.
This function returns a "struct guestfs_application_list *", or NULL
if there was an error.
The caller must call
"guestfs_free_application_list" after use.
(Added in 1.7.8)
guestfs_inspect_os¶
char **
guestfs_inspect_os (guestfs_h *g);
This function uses other libguestfs functions and certain heuristics to inspect
the disk(s) (usually disks belonging to a virtual machine), looking for
operating systems.
The list returned is empty if no operating systems were found.
If one operating system was found, then this returns a list with a single
element, which is the name of the root filesystem of this operating system. It
is also possible for this function to return a list containing more than one
element, indicating a dual-boot or multi-boot virtual machine, with each
element being the root filesystem of one of the operating systems.
You can pass the root string(s) returned to other
"guestfs_inspect_get_*" functions in order to query further
information about each operating system, such as the name and version.
This function uses other libguestfs features such as
"guestfs_mount_ro" and "guestfs_umount_all" in order to
mount and unmount filesystems and look at the contents. This should be called
with no disks currently mounted. The function may also use Augeas, so any
existing Augeas handle will be closed.
This function cannot decrypt encrypted disks. The caller must do that first
(supplying the necessary keys) if the disk is encrypted.
Please read "INSPECTION" in
guestfs(3) for more details.
See also "guestfs_list_filesystems".
This function returns a NULL-terminated array of strings (like
environ(3)), or NULL if there was an error.
The caller must free the
strings and the array after use.
(Added in 1.5.3)
guestfs_is_blockdev¶
int
guestfs_is_blockdev (guestfs_h *g,
const char *path);
This returns "true" if and only if there is a block device with the
given "path" name.
See also "guestfs_stat".
This function returns a C truth value on success or -1 on error.
(Added in 1.5.10)
guestfs_is_chardev¶
int
guestfs_is_chardev (guestfs_h *g,
const char *path);
This returns "true" if and only if there is a character device with
the given "path" name.
See also "guestfs_stat".
This function returns a C truth value on success or -1 on error.
(Added in 1.5.10)
guestfs_is_config¶
int
guestfs_is_config (guestfs_h *g);
This returns true iff this handle is being configured (in the "CONFIG"
state).
For more information on states, see
guestfs(3).
This function returns a C truth value on success or -1 on error.
(Added in 1.0.2)
guestfs_is_dir¶
int
guestfs_is_dir (guestfs_h *g,
const char *path);
This returns "true" if and only if there is a directory with the given
"path" name. Note that it returns false for other objects like
files.
See also "guestfs_stat".
This function returns a C truth value on success or -1 on error.
(Added in 0.8)
guestfs_is_fifo¶
int
guestfs_is_fifo (guestfs_h *g,
const char *path);
This returns "true" if and only if there is a FIFO (named pipe) with
the given "path" name.
See also "guestfs_stat".
This function returns a C truth value on success or -1 on error.
(Added in 1.5.10)
guestfs_is_file¶
int
guestfs_is_file (guestfs_h *g,
const char *path);
This returns "true" if and only if there is a regular file with the
given "path" name. Note that it returns false for other objects like
directories.
See also "guestfs_stat".
This function returns a C truth value on success or -1 on error.
(Added in 0.8)
guestfs_is_launching¶
int
guestfs_is_launching (guestfs_h *g);
This returns true iff this handle is launching the subprocess (in the
"LAUNCHING" state).
For more information on states, see
guestfs(3).
This function returns a C truth value on success or -1 on error.
(Added in 1.0.2)
guestfs_is_lv¶
int
guestfs_is_lv (guestfs_h *g,
const char *device);
This command tests whether "device" is a logical volume, and returns
true iff this is the case.
This function returns a C truth value on success or -1 on error.
(Added in 1.5.3)
guestfs_is_ready¶
int
guestfs_is_ready (guestfs_h *g);
This returns true iff this handle is ready to accept commands (in the
"READY" state).
For more information on states, see
guestfs(3).
This function returns a C truth value on success or -1 on error.
(Added in 1.0.2)
guestfs_is_socket¶
int
guestfs_is_socket (guestfs_h *g,
const char *path);
This returns "true" if and only if there is a Unix domain socket with
the given "path" name.
See also "guestfs_stat".
This function returns a C truth value on success or -1 on error.
(Added in 1.5.10)
guestfs_is_symlink¶
int
guestfs_is_symlink (guestfs_h *g,
const char *path);
This returns "true" if and only if there is a symbolic link with the
given "path" name.
See also "guestfs_stat".
This function returns a C truth value on success or -1 on error.
(Added in 1.5.10)
guestfs_is_zero¶
int
guestfs_is_zero (guestfs_h *g,
const char *path);
This returns true iff the file exists and the file is empty or it contains all
zero bytes.
This function returns a C truth value on success or -1 on error.
(Added in 1.11.8)
guestfs_is_zero_device¶
int
guestfs_is_zero_device (guestfs_h *g,
const char *device);
This returns true iff the device exists and contains all zero bytes.
Note that for large devices this can take a long time to run.
This function returns a C truth value on success or -1 on error.
(Added in 1.11.8)
guestfs_isoinfo¶
struct guestfs_isoinfo *
guestfs_isoinfo (guestfs_h *g,
const char *isofile);
This is the same as "guestfs_isoinfo_device" except that it works for
an ISO file located inside some other mounted filesystem. Note that in the
common case where you have added an ISO file as a libguestfs device, you would
not call this. Instead you would call
"guestfs_isoinfo_device".
This function returns a "struct guestfs_isoinfo *", or NULL if there
was an error.
The caller must call
"guestfs_free_isoinfo" after use.
(Added in 1.17.19)
guestfs_isoinfo_device¶
struct guestfs_isoinfo *
guestfs_isoinfo_device (guestfs_h *g,
const char *device);
"device" is an ISO device. This returns a struct of information read
from the primary volume descriptor (the ISO equivalent of the superblock) of
the device.
Usually it is more efficient to use the
isoinfo(1) command with the
-d option on the host to analyze ISO files, instead of going through
libguestfs.
For information on the primary volume descriptor fields, see
<
http://wiki.osdev.org/ISO_9660#The_Primary_Volume_Descriptor>
This function returns a "struct guestfs_isoinfo *", or NULL if there
was an error.
The caller must call
"guestfs_free_isoinfo" after use.
(Added in 1.17.19)
guestfs_kill_subprocess¶
int
guestfs_kill_subprocess (guestfs_h *g);
This kills the qemu subprocess. You should never need to call this.
This function returns 0 on success or -1 on error.
(Added in 0.3)
guestfs_launch¶
int
guestfs_launch (guestfs_h *g);
Internally libguestfs is implemented by running a virtual machine using
qemu(1).
You should call this after configuring the handle (eg. adding drives) but before
performing any actions.
This function returns 0 on success or -1 on error.
This long-running command can generate progress notification messages so that
the caller can display a progress bar or indicator. To receive these messages,
the caller must register a progress event callback. See
"GUESTFS_EVENT_PROGRESS" in
guestfs(3).
(Added in 0.3)
guestfs_lchown¶
int
guestfs_lchown (guestfs_h *g,
int owner,
int group,
const char *path);
Change the file owner to "owner" and group to "group". This
is like "guestfs_chown" but if "path" is a symlink then
the link itself is changed, not the target.
Only numeric uid and gid are supported. If you want to use names, you will need
to locate and parse the password file yourself (Augeas support makes this
relatively easy).
This function returns 0 on success or -1 on error.
(Added in 1.0.77)
guestfs_lgetxattr¶
char *
guestfs_lgetxattr (guestfs_h *g,
const char *path,
const char *name,
size_t *size_r);
Get a single extended attribute from file "path" named
"name". If "path" is a symlink, then this call returns an
extended attribute from the symlink.
Normally it is better to get all extended attributes from a file in one go by
calling "guestfs_getxattrs". However some Linux filesystem
implementations are buggy and do not provide a way to list out attributes. For
these filesystems (notably ntfs-3g) you have to know the names of the extended
attributes you want in advance and call this function.
Extended attribute values are blobs of binary data. If there is no extended
attribute named "name", this returns an error.
See also: "guestfs_lgetxattrs", "guestfs_getxattr",
attr(5).
This function returns a buffer, or NULL on error. The size of the returned
buffer is written to *size_r.
The caller must free the returned buffer
after use.
(Added in 1.7.24)
guestfs_lgetxattrs¶
struct guestfs_xattr_list *
guestfs_lgetxattrs (guestfs_h *g,
const char *path);
This is the same as "guestfs_getxattrs", but if "path" is a
symbolic link, then it returns the extended attributes of the link itself.
This function returns a "struct guestfs_xattr_list *", or NULL if
there was an error.
The caller must call
"guestfs_free_xattr_list" after use.
(Added in 1.0.59)
guestfs_list_9p¶
char **
guestfs_list_9p (guestfs_h *g);
List all 9p filesystems attached to the guest. A list of mount tags is returned.
This function returns a NULL-terminated array of strings (like
environ(3)), or NULL if there was an error.
The caller must free the
strings and the array after use.
(Added in 1.11.12)
guestfs_list_devices¶
char **
guestfs_list_devices (guestfs_h *g);
List all the block devices.
The full block device names are returned, eg. "/dev/sda".
See also "guestfs_list_filesystems".
This function returns a NULL-terminated array of strings (like
environ(3)), or NULL if there was an error.
The caller must free the
strings and the array after use.
(Added in 0.4)
guestfs_list_dm_devices¶
char **
guestfs_list_dm_devices (guestfs_h *g);
List all device mapper devices.
The returned list contains "/dev/mapper/*" devices, eg. ones created
by a previous call to "guestfs_luks_open".
Device mapper devices which correspond to logical volumes are
not
returned in this list. Call "guestfs_lvs" if you want to list
logical volumes.
This function returns a NULL-terminated array of strings (like
environ(3)), or NULL if there was an error.
The caller must free the
strings and the array after use.
(Added in 1.11.15)
guestfs_list_filesystems¶
char **
guestfs_list_filesystems (guestfs_h *g);
This inspection command looks for filesystems on partitions, block devices and
logical volumes, returning a list of devices containing filesystems and their
type.
The return value is a hash, where the keys are the devices containing
filesystems, and the values are the filesystem types. For example:
"/dev/sda1" => "ntfs"
"/dev/sda2" => "ext2"
"/dev/vg_guest/lv_root" => "ext4"
"/dev/vg_guest/lv_swap" => "swap"
The value can have the special value "unknown", meaning the content of
the device is undetermined or empty. "swap" means a Linux swap
partition.
This command runs other libguestfs commands, which might include
"guestfs_mount" and "guestfs_umount", and therefore you
should use this soon after launch and only when nothing is mounted.
Not all of the filesystems returned will be mountable. In particular, swap
partitions are returned in the list. Also this command does not check that
each filesystem found is valid and mountable, and some filesystems might be
mountable but require special options. Filesystems may not all belong to a
single logical operating system (use "guestfs_inspect_os" to look
for OSes).
This function returns a NULL-terminated array of strings, or NULL if there was
an error. The array of strings will always have length "2n+1", where
"n" keys and values alternate, followed by the trailing NULL entry.
The caller must free the strings and the array after use.
(Added in 1.5.15)
guestfs_list_md_devices¶
char **
guestfs_list_md_devices (guestfs_h *g);
List all Linux md devices.
This function returns a NULL-terminated array of strings (like
environ(3)), or NULL if there was an error.
The caller must free the
strings and the array after use.
(Added in 1.15.4)
guestfs_list_partitions¶
char **
guestfs_list_partitions (guestfs_h *g);
List all the partitions detected on all block devices.
The full partition device names are returned, eg. "/dev/sda1"
This does not return logical volumes. For that you will need to call
"guestfs_lvs".
See also "guestfs_list_filesystems".
This function returns a NULL-terminated array of strings (like
environ(3)), or NULL if there was an error.
The caller must free the
strings and the array after use.
(Added in 0.4)
guestfs_ll¶
char *
guestfs_ll (guestfs_h *g,
const char *directory);
List the files in "directory" (relative to the root directory, there
is no cwd) in the format of 'ls -la'.
This command is mostly useful for interactive sessions. It is
not
intended that you try to parse the output string.
This function returns a string, or NULL on error.
The caller must free the
returned string after use.
(Added in 0.4)
guestfs_llz¶
char *
guestfs_llz (guestfs_h *g,
const char *directory);
List the files in "directory" in the format of 'ls -laZ'.
This command is mostly useful for interactive sessions. It is
not
intended that you try to parse the output string.
This function returns a string, or NULL on error.
The caller must free the
returned string after use.
(Added in 1.17.6)
guestfs_ln¶
int
guestfs_ln (guestfs_h *g,
const char *target,
const char *linkname);
This command creates a hard link using the "ln" command.
This function returns 0 on success or -1 on error.
(Added in 1.0.66)
guestfs_ln_f¶
int
guestfs_ln_f (guestfs_h *g,
const char *target,
const char *linkname);
This command creates a hard link using the "ln -f" command. The
-f option removes the link ("linkname") if it exists already.
This function returns 0 on success or -1 on error.
(Added in 1.0.66)
guestfs_ln_s¶
int
guestfs_ln_s (guestfs_h *g,
const char *target,
const char *linkname);
This command creates a symbolic link using the "ln -s" command.
This function returns 0 on success or -1 on error.
(Added in 1.0.66)
guestfs_ln_sf¶
int
guestfs_ln_sf (guestfs_h *g,
const char *target,
const char *linkname);
This command creates a symbolic link using the "ln -sf" command, The
-f option removes the link ("linkname") if it exists already.
This function returns 0 on success or -1 on error.
(Added in 1.0.66)
guestfs_lremovexattr¶
int
guestfs_lremovexattr (guestfs_h *g,
const char *xattr,
const char *path);
This is the same as "guestfs_removexattr", but if "path" is
a symbolic link, then it removes an extended attribute of the link itself.
This function returns 0 on success or -1 on error.
(Added in 1.0.59)
guestfs_ls¶
char **
guestfs_ls (guestfs_h *g,
const char *directory);
List the files in "directory" (relative to the root directory, there
is no cwd). The '.' and '..' entries are not returned, but hidden files are
shown.
This command is mostly useful for interactive sessions. Programs should probably
use "guestfs_readdir" instead.
This function returns a NULL-terminated array of strings (like
environ(3)), or NULL if there was an error.
The caller must free the
strings and the array after use.
(Added in 0.4)
guestfs_lsetxattr¶
int
guestfs_lsetxattr (guestfs_h *g,
const char *xattr,
const char *val,
int vallen,
const char *path);
This is the same as "guestfs_setxattr", but if "path" is a
symbolic link, then it sets an extended attribute of the link itself.
This function returns 0 on success or -1 on error.
(Added in 1.0.59)
guestfs_lstat¶
struct guestfs_stat *
guestfs_lstat (guestfs_h *g,
const char *path);
Returns file information for the given "path".
This is the same as "guestfs_stat" except that if "path" is
a symbolic link, then the link is stat-ed, not the file it refers to.
This is the same as the
lstat(2) system call.
This function returns a "struct guestfs_stat *", or NULL if there was
an error.
The caller must call "guestfs_free_stat"
after use.
(Added in 0.9.2)
guestfs_lstatlist¶
struct guestfs_stat_list *
guestfs_lstatlist (guestfs_h *g,
const char *path,
char *const *names);
This call allows you to perform the "guestfs_lstat" operation on
multiple files, where all files are in the directory "path".
"names" is the list of files from this directory.
On return you get a list of stat structs, with a one-to-one correspondence to
the "names" list. If any name did not exist or could not be lstat'd,
then the "ino" field of that structure is set to "-1".
This call is intended for programs that want to efficiently list a directory
contents without making many round-trips. See also
"guestfs_lxattrlist" for a similarly efficient call for getting
extended attributes. Very long directory listings might cause the protocol
message size to be exceeded, causing this call to fail. The caller must split
up such requests into smaller groups of names.
This function returns a "struct guestfs_stat_list *", or NULL if there
was an error.
The caller must call
"guestfs_free_stat_list" after use.
(Added in 1.0.77)
guestfs_luks_add_key¶
int
guestfs_luks_add_key (guestfs_h *g,
const char *device,
const char *key,
const char *newkey,
int keyslot);
This command adds a new key on LUKS device "device". "key"
is any existing key, and is used to access the device. "newkey" is
the new key to add. "keyslot" is the key slot that will be replaced.
Note that if "keyslot" already contains a key, then this command will
fail. You have to use "guestfs_luks_kill_slot" first to remove that
key.
This function returns 0 on success or -1 on error.
This function takes a key or passphrase parameter which could contain sensitive
material. Read the section "KEYS AND PASSPHRASES" for more
information.
(Added in 1.5.2)
guestfs_luks_close¶
int
guestfs_luks_close (guestfs_h *g,
const char *device);
This closes a LUKS device that was created earlier by
"guestfs_luks_open" or "guestfs_luks_open_ro". The
"device" parameter must be the name of the LUKS mapping device (ie.
"/dev/mapper/mapname") and
not the name of the underlying
block device.
This function returns 0 on success or -1 on error.
(Added in 1.5.1)
int
guestfs_luks_format (guestfs_h *g,
const char *device,
const char *key,
int keyslot);
This command erases existing data on "device" and formats the device
as a LUKS encrypted device. "key" is the initial key, which is added
to key slot "slot". (LUKS supports 8 key slots, numbered 0-7).
This function returns 0 on success or -1 on error.
This function takes a key or passphrase parameter which could contain sensitive
material. Read the section "KEYS AND PASSPHRASES" for more
information.
(Added in 1.5.2)
int
guestfs_luks_format_cipher (guestfs_h *g,
const char *device,
const char *key,
int keyslot,
const char *cipher);
This command is the same as "guestfs_luks_format" but it also allows
you to set the "cipher" used.
This function returns 0 on success or -1 on error.
This function takes a key or passphrase parameter which could contain sensitive
material. Read the section "KEYS AND PASSPHRASES" for more
information.
(Added in 1.5.2)
guestfs_luks_kill_slot¶
int
guestfs_luks_kill_slot (guestfs_h *g,
const char *device,
const char *key,
int keyslot);
This command deletes the key in key slot "keyslot" from the encrypted
LUKS device "device". "key" must be one of the
other keys.
This function returns 0 on success or -1 on error.
This function takes a key or passphrase parameter which could contain sensitive
material. Read the section "KEYS AND PASSPHRASES" for more
information.
(Added in 1.5.2)
guestfs_luks_open¶
int
guestfs_luks_open (guestfs_h *g,
const char *device,
const char *key,
const char *mapname);
This command opens a block device which has been encrypted according to the
Linux Unified Key Setup (LUKS) standard.
"device" is the encrypted block device or partition.
The caller must supply one of the keys associated with the LUKS block device, in
the "key" parameter.
This creates a new block device called "/dev/mapper/mapname". Reads
and writes to this block device are decrypted from and encrypted to the
underlying "device" respectively.
If this block device contains LVM volume groups, then calling
"guestfs_vgscan" followed by "guestfs_vg_activate_all"
will make them visible.
Use "guestfs_list_dm_devices" to list all device mapper devices.
This function returns 0 on success or -1 on error.
This function takes a key or passphrase parameter which could contain sensitive
material. Read the section "KEYS AND PASSPHRASES" for more
information.
(Added in 1.5.1)
guestfs_luks_open_ro¶
int
guestfs_luks_open_ro (guestfs_h *g,
const char *device,
const char *key,
const char *mapname);
This is the same as "guestfs_luks_open" except that a read-only
mapping is created.
This function returns 0 on success or -1 on error.
This function takes a key or passphrase parameter which could contain sensitive
material. Read the section "KEYS AND PASSPHRASES" for more
information.
(Added in 1.5.1)
guestfs_lvcreate¶
int
guestfs_lvcreate (guestfs_h *g,
const char *logvol,
const char *volgroup,
int mbytes);
This creates an LVM logical volume called "logvol" on the volume group
"volgroup", with "size" megabytes.
This function returns 0 on success or -1 on error.
(Added in 0.8)
guestfs_lvcreate_free¶
int
guestfs_lvcreate_free (guestfs_h *g,
const char *logvol,
const char *volgroup,
int percent);
Create an LVM logical volume called "/dev/volgroup/logvol", using
approximately "percent" % of the free space remaining in the volume
group. Most usefully, when "percent" is 100 this will create the
largest possible LV.
This function returns 0 on success or -1 on error.
(Added in 1.17.18)
guestfs_lvm_canonical_lv_name¶
char *
guestfs_lvm_canonical_lv_name (guestfs_h *g,
const char *lvname);
This converts alternative naming schemes for LVs that you might find to the
canonical name. For example, "/dev/mapper/VG-LV" is converted to
"/dev/VG/LV".
This command returns an error if the "lvname" parameter does not refer
to a logical volume.
See also "guestfs_is_lv".
This function returns a string, or NULL on error.
The caller must free the
returned string after use.
(Added in 1.5.24)
guestfs_lvm_clear_filter¶
int
guestfs_lvm_clear_filter (guestfs_h *g);
This undoes the effect of "guestfs_lvm_set_filter". LVM will be able
to see every block device.
This command also clears the LVM cache and performs a volume group scan.
This function returns 0 on success or -1 on error.
(Added in 1.5.1)
guestfs_lvm_remove_all¶
int
guestfs_lvm_remove_all (guestfs_h *g);
This command removes all LVM logical volumes, volume groups and physical
volumes.
This function returns 0 on success or -1 on error.
(Added in 0.8)
guestfs_lvm_set_filter¶
int
guestfs_lvm_set_filter (guestfs_h *g,
char *const *devices);
This sets the LVM device filter so that LVM will only be able to "see"
the block devices in the list "devices", and will ignore all other
attached block devices.
Where disk image(s) contain duplicate PVs or VGs, this command is useful to get
LVM to ignore the duplicates, otherwise LVM can get confused. Note also there
are two types of duplication possible: either cloned PVs/VGs which have
identical UUIDs; or VGs that are not cloned but just happen to have the same
name. In normal operation you cannot create this situation, but you can do it
outside LVM, eg. by cloning disk images or by bit twiddling inside the LVM
metadata.
This command also clears the LVM cache and performs a volume group scan.
You can filter whole block devices or individual partitions.
You cannot use this if any VG is currently in use (eg. contains a mounted
filesystem), even if you are not filtering out that VG.
This function returns 0 on success or -1 on error.
(Added in 1.5.1)
guestfs_lvremove¶
int
guestfs_lvremove (guestfs_h *g,
const char *device);
Remove an LVM logical volume "device", where "device" is the
path to the LV, such as "/dev/VG/LV".
You can also remove all LVs in a volume group by specifying the VG name,
"/dev/VG".
This function returns 0 on success or -1 on error.
(Added in 1.0.13)
guestfs_lvrename¶
int
guestfs_lvrename (guestfs_h *g,
const char *logvol,
const char *newlogvol);
Rename a logical volume "logvol" with the new name
"newlogvol".
This function returns 0 on success or -1 on error.
(Added in 1.0.83)
guestfs_lvresize¶
int
guestfs_lvresize (guestfs_h *g,
const char *device,
int mbytes);
This resizes (expands or shrinks) an existing LVM logical volume to
"mbytes". When reducing, data in the reduced part is lost.
This function returns 0 on success or -1 on error.
(Added in 1.0.27)
guestfs_lvresize_free¶
int
guestfs_lvresize_free (guestfs_h *g,
const char *lv,
int percent);
This expands an existing logical volume "lv" so that it fills
"pc"% of the remaining free space in the volume group. Commonly you
would call this with pc = 100 which expands the logical volume as much as
possible, using all remaining free space in the volume group.
This function returns 0 on success or -1 on error.
(Added in 1.3.3)
guestfs_lvs¶
char **
guestfs_lvs (guestfs_h *g);
List all the logical volumes detected. This is the equivalent of the
lvs(8) command.
This returns a list of the logical volume device names (eg.
"/dev/VolGroup00/LogVol00").
See also "guestfs_lvs_full", "guestfs_list_filesystems".
This function returns a NULL-terminated array of strings (like
environ(3)), or NULL if there was an error.
The caller must free the
strings and the array after use.
(Added in 0.4)
guestfs_lvs_full¶
struct guestfs_lvm_lv_list *
guestfs_lvs_full (guestfs_h *g);
List all the logical volumes detected. This is the equivalent of the
lvs(8) command. The "full" version includes all fields.
This function returns a "struct guestfs_lvm_lv_list *", or NULL if
there was an error.
The caller must call
"guestfs_free_lvm_lv_list" after use.
(Added in 0.4)
guestfs_lvuuid¶
char *
guestfs_lvuuid (guestfs_h *g,
const char *device);
This command returns the UUID of the LVM LV "device".
This function returns a string, or NULL on error.
The caller must free the
returned string after use.
(Added in 1.0.87)
guestfs_lxattrlist¶
struct guestfs_xattr_list *
guestfs_lxattrlist (guestfs_h *g,
const char *path,
char *const *names);
This call allows you to get the extended attributes of multiple files, where all
files are in the directory "path". "names" is the list of
files from this directory.
On return you get a flat list of xattr structs which must be interpreted
sequentially. The first xattr struct always has a zero-length
"attrname". "attrval" in this struct is zero-length to
indicate there was an error doing "lgetxattr" for this file,
or is a C string which is a decimal number (the number of following
attributes for this file, which could be "0"). Then after the first
xattr struct are the zero or more attributes for the first named file. This
repeats for the second and subsequent files.
This call is intended for programs that want to efficiently list a directory
contents without making many round-trips. See also
"guestfs_lstatlist" for a similarly efficient call for getting
standard stats. Very long directory listings might cause the protocol message
size to be exceeded, causing this call to fail. The caller must split up such
requests into smaller groups of names.
This function returns a "struct guestfs_xattr_list *", or NULL if
there was an error.
The caller must call
"guestfs_free_xattr_list" after use.
(Added in 1.0.77)
guestfs_md_create¶
int
guestfs_md_create (guestfs_h *g,
const char *name,
char *const *devices,
...);
You may supply a list of optional arguments to this call. Use zero or more of
the following pairs of parameters, and terminate the list with "-1"
on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_MD_CREATE_MISSINGBITMAP, int64_t missingbitmap,
GUESTFS_MD_CREATE_NRDEVICES, int nrdevices,
GUESTFS_MD_CREATE_SPARE, int spare,
GUESTFS_MD_CREATE_CHUNK, int64_t chunk,
GUESTFS_MD_CREATE_LEVEL, const char *level,
Create a Linux md (RAID) device named "name" on the devices in the
list "devices".
The optional parameters are:
- "missingbitmap"
- A bitmap of missing devices. If a bit is set it means that
a missing device is added to the array. The least significant bit
corresponds to the first device in the array.
As examples:
If "devices = ["/dev/sda"]" and "missingbitmap =
0x1" then the resulting array would be "[<missing>,
"/dev/sda"]".
If "devices = ["/dev/sda"]" and "missingbitmap =
0x2" then the resulting array would be "["/dev/sda",
<missing>]".
This defaults to 0 (no missing devices).
The length of "devices" + the number of bits set in
"missingbitmap" must equal "nrdevices" +
"spare".
- "nrdevices"
- The number of active RAID devices.
If not set, this defaults to the length of "devices" plus the
number of bits set in "missingbitmap".
- "spare"
- The number of spare devices.
If not set, this defaults to 0.
- "chunk"
- The chunk size in bytes.
- "level"
- The RAID level, which can be one of: linear,
raid0, 0, stripe, raid1, 1,
mirror, raid4, 4, raid5, 5,
raid6, 6, raid10, 10. Some of these are
synonymous, and more levels may be added in future.
If not set, this defaults to "raid1".
This function returns 0 on success or -1 on error.
(Added in 1.15.6)
guestfs_md_create_va¶
int
guestfs_md_create_va (guestfs_h *g,
const char *name,
char *const *devices,
va_list args);
This is the "va_list variant" of "guestfs_md_create".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_md_create_argv¶
int
guestfs_md_create_argv (guestfs_h *g,
const char *name,
char *const *devices,
const struct guestfs_md_create_argv *optargs);
This is the "argv variant" of "guestfs_md_create".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_md_detail¶
char **
guestfs_md_detail (guestfs_h *g,
const char *md);
This command exposes the output of 'mdadm -DY <md>'. The following fields
are usually present in the returned hash. Other fields may also be present.
- "level"
- The raid level of the MD device.
- "devices"
- The number of underlying devices in the MD device.
- "metadata"
- The metadata version used.
- "uuid"
- The UUID of the MD device.
- "name"
- The name of the MD device.
This function returns a NULL-terminated array of strings, or NULL if there was
an error. The array of strings will always have length "2n+1", where
"n" keys and values alternate, followed by the trailing NULL entry.
The caller must free the strings and the array after use.
(Added in 1.15.6)
guestfs_md_stat¶
struct guestfs_mdstat_list *
guestfs_md_stat (guestfs_h *g,
const char *md);
This call returns a list of the underlying devices which make up the single
software RAID array device "md".
To get a list of software RAID devices, call
"guestfs_list_md_devices".
Each structure returned corresponds to one device along with additional status
information:
- "mdstat_device"
- The name of the underlying device.
- "mdstat_index"
- The index of this device within the array.
- "mdstat_flags"
- Flags associated with this device. This is a string
containing (in no specific order) zero or more of the following
flags:
- "W"
- write-mostly
- "F"
- device is faulty
- "S"
- device is a RAID spare
- "R"
- replacement
This function returns a "struct guestfs_mdstat_list *", or NULL if
there was an error.
The caller must call
"guestfs_free_mdstat_list" after use.
(Added in 1.17.21)
guestfs_md_stop¶
int
guestfs_md_stop (guestfs_h *g,
const char *md);
This command deactivates the MD array named "md". The device is
stopped, but it is not destroyed or zeroed.
This function returns 0 on success or -1 on error.
(Added in 1.15.6)
guestfs_mkdir¶
int
guestfs_mkdir (guestfs_h *g,
const char *path);
Create a directory named "path".
This function returns 0 on success or -1 on error.
(Added in 0.8)
guestfs_mkdir_mode¶
int
guestfs_mkdir_mode (guestfs_h *g,
const char *path,
int mode);
This command creates a directory, setting the initial permissions of the
directory to "mode".
For common Linux filesystems, the actual mode which is set will be "mode
& ~umask & 01777". Non-native-Linux filesystems may interpret the
mode in other ways.
See also "guestfs_mkdir", "guestfs_umask"
This function returns 0 on success or -1 on error.
(Added in 1.0.77)
guestfs_mkdir_p¶
int
guestfs_mkdir_p (guestfs_h *g,
const char *path);
Create a directory named "path", creating any parent directories as
necessary. This is like the "mkdir -p" shell command.
This function returns 0 on success or -1 on error.
(Added in 0.8)
guestfs_mkdtemp¶
char *
guestfs_mkdtemp (guestfs_h *g,
const char *tmpl);
This command creates a temporary directory. The "tmpl" parameter
should be a full pathname for the temporary directory name with the final six
characters being "XXXXXX".
For example: "/tmp/myprogXXXXXX" or "/Temp/myprogXXXXXX",
the second one being suitable for Windows filesystems.
The name of the temporary directory that was created is returned.
The temporary directory is created with mode 0700 and is owned by root.
The caller is responsible for deleting the temporary directory and its contents
after use.
See also:
mkdtemp(3)
This function returns a string, or NULL on error.
The caller must free the
returned string after use.
(Added in 1.0.54)
guestfs_mke2fs_J¶
int
guestfs_mke2fs_J (guestfs_h *g,
const char *fstype,
int blocksize,
const char *device,
const char *journal);
This creates an ext2/3/4 filesystem on "device" with an external
journal on "journal". It is equivalent to the command:
mke2fs -t fstype -b blocksize -J device=<journal> <device>
See also "guestfs_mke2journal".
This function returns 0 on success or -1 on error.
(Added in 1.0.68)
guestfs_mke2fs_JL¶
int
guestfs_mke2fs_JL (guestfs_h *g,
const char *fstype,
int blocksize,
const char *device,
const char *label);
This creates an ext2/3/4 filesystem on "device" with an external
journal on the journal labeled "label".
See also "guestfs_mke2journal_L".
This function returns 0 on success or -1 on error.
(Added in 1.0.68)
guestfs_mke2fs_JU¶
int
guestfs_mke2fs_JU (guestfs_h *g,
const char *fstype,
int blocksize,
const char *device,
const char *uuid);
This creates an ext2/3/4 filesystem on "device" with an external
journal on the journal with UUID "uuid".
See also "guestfs_mke2journal_U".
This function returns 0 on success or -1 on error.
(Added in 1.0.68)
guestfs_mke2journal¶
int
guestfs_mke2journal (guestfs_h *g,
int blocksize,
const char *device);
This creates an ext2 external journal on "device". It is equivalent to
the command:
mke2fs -O journal_dev -b blocksize device
This function returns 0 on success or -1 on error.
(Added in 1.0.68)
guestfs_mke2journal_L¶
int
guestfs_mke2journal_L (guestfs_h *g,
int blocksize,
const char *label,
const char *device);
This creates an ext2 external journal on "device" with label
"label".
This function returns 0 on success or -1 on error.
(Added in 1.0.68)
guestfs_mke2journal_U¶
int
guestfs_mke2journal_U (guestfs_h *g,
int blocksize,
const char *uuid,
const char *device);
This creates an ext2 external journal on "device" with UUID
"uuid".
This function returns 0 on success or -1 on error.
(Added in 1.0.68)
guestfs_mkfifo¶
int
guestfs_mkfifo (guestfs_h *g,
int mode,
const char *path);
This call creates a FIFO (named pipe) called "path" with mode
"mode". It is just a convenient wrapper around
"guestfs_mknod".
The mode actually set is affected by the umask.
This function returns 0 on success or -1 on error.
(Added in 1.0.55)
guestfs_mkfs¶
int
guestfs_mkfs (guestfs_h *g,
const char *fstype,
const char *device);
This creates a filesystem on "device" (usually a partition or LVM
logical volume). The filesystem type is "fstype", for example
"ext3".
This function returns 0 on success or -1 on error.
(Added in 0.8)
guestfs_mkfs_b¶
int
guestfs_mkfs_b (guestfs_h *g,
const char *fstype,
int blocksize,
const char *device);
This function is deprecated. In new code, use the
"guestfs_mkfs_opts" call instead.
Deprecated functions will not be removed from the API, but the fact that they
are deprecated indicates that there are problems with correct use of these
functions.
This call is similar to "guestfs_mkfs", but it allows you to control
the block size of the resulting filesystem. Supported block sizes depend on
the filesystem type, but typically they are 1024, 2048 or 4096 only.
For VFAT and NTFS the "blocksize" parameter is treated as the
requested cluster size.
This function returns 0 on success or -1 on error.
(Added in 1.0.68)
guestfs_mkfs_btrfs¶
int
guestfs_mkfs_btrfs (guestfs_h *g,
char *const *devices,
...);
You may supply a list of optional arguments to this call. Use zero or more of
the following pairs of parameters, and terminate the list with "-1"
on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_MKFS_BTRFS_ALLOCSTART, int64_t allocstart,
GUESTFS_MKFS_BTRFS_BYTECOUNT, int64_t bytecount,
GUESTFS_MKFS_BTRFS_DATATYPE, const char *datatype,
GUESTFS_MKFS_BTRFS_LEAFSIZE, int leafsize,
GUESTFS_MKFS_BTRFS_LABEL, const char *label,
GUESTFS_MKFS_BTRFS_METADATA, const char *metadata,
GUESTFS_MKFS_BTRFS_NODESIZE, int nodesize,
GUESTFS_MKFS_BTRFS_SECTORSIZE, int sectorsize,
Create a btrfs filesystem, allowing all configurables to be set. For more
information on the optional arguments, see
mkfs.btrfs(8).
Since btrfs filesystems can span multiple devices, this takes a non-empty list
of devices.
To create general filesystems, use "guestfs_mkfs_opts".
This function returns 0 on success or -1 on error.
(Added in 1.17.25)
guestfs_mkfs_btrfs_va¶
int
guestfs_mkfs_btrfs_va (guestfs_h *g,
char *const *devices,
va_list args);
This is the "va_list variant" of "guestfs_mkfs_btrfs".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_mkfs_btrfs_argv¶
int
guestfs_mkfs_btrfs_argv (guestfs_h *g,
char *const *devices,
const struct guestfs_mkfs_btrfs_argv *optargs);
This is the "argv variant" of "guestfs_mkfs_btrfs".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_mkfs_opts¶
int
guestfs_mkfs_opts (guestfs_h *g,
const char *fstype,
const char *device,
...);
You may supply a list of optional arguments to this call. Use zero or more of
the following pairs of parameters, and terminate the list with "-1"
on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_MKFS_OPTS_BLOCKSIZE, int blocksize,
GUESTFS_MKFS_OPTS_FEATURES, const char *features,
GUESTFS_MKFS_OPTS_INODE, int inode,
GUESTFS_MKFS_OPTS_SECTORSIZE, int sectorsize,
This function creates a filesystem on "device". The filesystem type is
"fstype", for example "ext3".
The optional arguments are:
- "blocksize"
- The filesystem block size. Supported block sizes depend on
the filesystem type, but typically they are 1024, 2048 or 4096 for Linux
ext2/3 filesystems.
For VFAT and NTFS the "blocksize" parameter is treated as the
requested cluster size.
For UFS block sizes, please see mkfs.ufs(8).
- "features"
- This passes the -O parameter to the external mkfs
program.
For certain filesystem types, this allows extra filesystem features to be
selected. See mke2fs(8) and mkfs.ufs(8) for more details.
You cannot use this optional parameter with the "gfs" or
"gfs2" filesystem type.
- "inode"
- This passes the -I parameter to the external
mke2fs(8) program which sets the inode size (only for ext2/3/4
filesystems at present).
- "sectorsize"
- This passes the -S parameter to external
mkfs.ufs(8) program, which sets sector size for ufs
filesystem.
This function returns 0 on success or -1 on error.
(Added in 1.7.19)
guestfs_mkfs_opts_va¶
int
guestfs_mkfs_opts_va (guestfs_h *g,
const char *fstype,
const char *device,
va_list args);
This is the "va_list variant" of "guestfs_mkfs_opts".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_mkfs_opts_argv¶
int
guestfs_mkfs_opts_argv (guestfs_h *g,
const char *fstype,
const char *device,
const struct guestfs_mkfs_opts_argv *optargs);
This is the "argv variant" of "guestfs_mkfs_opts".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_mkmountpoint¶
int
guestfs_mkmountpoint (guestfs_h *g,
const char *exemptpath);
"guestfs_mkmountpoint" and "guestfs_rmmountpoint" are
specialized calls that can be used to create extra mountpoints before mounting
the first filesystem.
These calls are
only necessary in some very limited circumstances, mainly
the case where you want to mount a mix of unrelated and/or read-only
filesystems together.
For example, live CDs often contain a "Russian doll" nest of
filesystems, an ISO outer layer, with a squashfs image inside, with an ext2/3
image inside that. You can unpack this as follows in guestfish:
add-ro Fedora-11-i686-Live.iso
run
mkmountpoint /cd
mkmountpoint /sqsh
mkmountpoint /ext3fs
mount /dev/sda /cd
mount-loop /cd/LiveOS/squashfs.img /sqsh
mount-loop /sqsh/LiveOS/ext3fs.img /ext3fs
The inner filesystem is now unpacked under the /ext3fs mountpoint.
"guestfs_mkmountpoint" is not compatible with
"guestfs_umount_all". You may get unexpected errors if you try to
mix these calls. It is safest to manually unmount filesystems and remove
mountpoints after use.
"guestfs_umount_all" unmounts filesystems by sorting the paths longest
first, so for this to work for manual mountpoints, you must ensure that the
innermost mountpoints have the longest pathnames, as in the example code
above.
For more details see <
https://bugzilla.redhat.com/show_bug.cgi?id=599503>
Autosync [see "guestfs_set_autosync", this is set by default on
handles] can cause "guestfs_umount_all" to be called when the handle
is closed which can also trigger these issues.
This function returns 0 on success or -1 on error.
(Added in 1.0.62)
guestfs_mknod¶
int
guestfs_mknod (guestfs_h *g,
int mode,
int devmajor,
int devminor,
const char *path);
This call creates block or character special devices, or named pipes (FIFOs).
The "mode" parameter should be the mode, using the standard constants.
"devmajor" and "devminor" are the device major and minor
numbers, only used when creating block and character special devices.
Note that, just like
mknod(2), the mode must be bitwise OR'd with
S_IFBLK, S_IFCHR, S_IFIFO or S_IFSOCK (otherwise this call just creates a
regular file). These constants are available in the standard Linux header
files, or you can use "guestfs_mknod_b", "guestfs_mknod_c"
or "guestfs_mkfifo" which are wrappers around this command which
bitwise OR in the appropriate constant for you.
The mode actually set is affected by the umask.
This function returns 0 on success or -1 on error.
(Added in 1.0.55)
guestfs_mknod_b¶
int
guestfs_mknod_b (guestfs_h *g,
int mode,
int devmajor,
int devminor,
const char *path);
This call creates a block device node called "path" with mode
"mode" and device major/minor "devmajor" and
"devminor". It is just a convenient wrapper around
"guestfs_mknod".
The mode actually set is affected by the umask.
This function returns 0 on success or -1 on error.
(Added in 1.0.55)
guestfs_mknod_c¶
int
guestfs_mknod_c (guestfs_h *g,
int mode,
int devmajor,
int devminor,
const char *path);
This call creates a char device node called "path" with mode
"mode" and device major/minor "devmajor" and
"devminor". It is just a convenient wrapper around
"guestfs_mknod".
The mode actually set is affected by the umask.
This function returns 0 on success or -1 on error.
(Added in 1.0.55)
guestfs_mkswap¶
int
guestfs_mkswap (guestfs_h *g,
const char *device);
Create a swap partition on "device".
This function returns 0 on success or -1 on error.
(Added in 1.0.55)
guestfs_mkswap_L¶
int
guestfs_mkswap_L (guestfs_h *g,
const char *label,
const char *device);
Create a swap partition on "device" with label "label".
Note that you cannot attach a swap label to a block device (eg.
"/dev/sda"), just to a partition. This appears to be a limitation of
the kernel or swap tools.
This function returns 0 on success or -1 on error.
(Added in 1.0.55)
guestfs_mkswap_U¶
int
guestfs_mkswap_U (guestfs_h *g,
const char *uuid,
const char *device);
Create a swap partition on "device" with UUID "uuid".
This function returns 0 on success or -1 on error.
(Added in 1.0.55)
guestfs_mkswap_file¶
int
guestfs_mkswap_file (guestfs_h *g,
const char *path);
Create a swap file.
This command just writes a swap file signature to an existing file. To create
the file itself, use something like "guestfs_fallocate".
This function returns 0 on success or -1 on error.
(Added in 1.0.66)
guestfs_modprobe¶
int
guestfs_modprobe (guestfs_h *g,
const char *modulename);
This loads a kernel module in the appliance.
The kernel module must have been whitelisted when libguestfs was built (see
"appliance/kmod.whitelist.in" in the source).
This function returns 0 on success or -1 on error.
(Added in 1.0.68)
guestfs_mount¶
int
guestfs_mount (guestfs_h *g,
const char *device,
const char *mountpoint);
Mount a guest disk at a position in the filesystem. Block devices are named
"/dev/sda", "/dev/sdb" and so on, as they were added to
the guest. If those block devices contain partitions, they will have the usual
names (eg. "/dev/sda1"). Also LVM "/dev/VG/LV"-style names
can be used.
The rules are the same as for
mount(2): A filesystem must first be
mounted on "/" before others can be mounted. Other filesystems can
only be mounted on directories which already exist.
The mounted filesystem is writable, if we have sufficient permissions on the
underlying device.
Before libguestfs 1.13.16, this call implicitly added the options
"sync" and "noatime". The "sync" option greatly
slowed writes and caused many problems for users. If your program might need
to work with older versions of libguestfs, use
"guestfs_mount_options" instead (using an empty string for the first
parameter if you don't want any options).
This function returns 0 on success or -1 on error.
(Added in 0.3)
guestfs_mount_9p¶
int
guestfs_mount_9p (guestfs_h *g,
const char *mounttag,
const char *mountpoint,
...);
You may supply a list of optional arguments to this call. Use zero or more of
the following pairs of parameters, and terminate the list with "-1"
on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_MOUNT_9P_OPTIONS, const char *options,
Mount the virtio-9p filesystem with the tag "mounttag" on the
directory "mountpoint".
If required, "trans=virtio" will be automatically added to the
options. Any other options required can be passed in the optional
"options" parameter.
This function returns 0 on success or -1 on error.
(Added in 1.11.12)
guestfs_mount_9p_va¶
int
guestfs_mount_9p_va (guestfs_h *g,
const char *mounttag,
const char *mountpoint,
va_list args);
This is the "va_list variant" of "guestfs_mount_9p".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_mount_9p_argv¶
int
guestfs_mount_9p_argv (guestfs_h *g,
const char *mounttag,
const char *mountpoint,
const struct guestfs_mount_9p_argv *optargs);
This is the "argv variant" of "guestfs_mount_9p".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_mount_local¶
int
guestfs_mount_local (guestfs_h *g,
const char *localmountpoint,
...);
You may supply a list of optional arguments to this call. Use zero or more of
the following pairs of parameters, and terminate the list with "-1"
on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_MOUNT_LOCAL_READONLY, int readonly,
GUESTFS_MOUNT_LOCAL_OPTIONS, const char *options,
GUESTFS_MOUNT_LOCAL_CACHETIMEOUT, int cachetimeout,
GUESTFS_MOUNT_LOCAL_DEBUGCALLS, int debugcalls,
This call exports the libguestfs-accessible filesystem to a local mountpoint
(directory) called "localmountpoint". Ordinary reads and writes to
files and directories under "localmountpoint" are redirected through
libguestfs.
If the optional "readonly" flag is set to true, then writes to the
filesystem return error "EROFS".
"options" is a comma-separated list of mount options. See
guestmount(1) for some useful options.
"cachetimeout" sets the timeout (in seconds) for cached directory
entries. The default is 60 seconds. See
guestmount(1) for further
information.
If "debugcalls" is set to true, then additional debugging information
is generated for every FUSE call.
When "guestfs_mount_local" returns, the filesystem is ready, but is
not processing requests (access to it will block). You have to call
"guestfs_mount_local_run" to run the main loop.
See "MOUNT LOCAL" in
guestfs(3) for full documentation.
This function returns 0 on success or -1 on error.
(Added in 1.17.22)
guestfs_mount_local_va¶
int
guestfs_mount_local_va (guestfs_h *g,
const char *localmountpoint,
va_list args);
This is the "va_list variant" of "guestfs_mount_local".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_mount_local_argv¶
int
guestfs_mount_local_argv (guestfs_h *g,
const char *localmountpoint,
const struct guestfs_mount_local_argv *optargs);
This is the "argv variant" of "guestfs_mount_local".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_mount_local_run¶
int
guestfs_mount_local_run (guestfs_h *g);
Run the main loop which translates kernel calls to libguestfs calls.
This should only be called after "guestfs_mount_local" returns
successfully. The call will not return until the filesystem is unmounted.
Note you must
not make concurrent libguestfs calls on the same
handle from another thread, with the exception of
"guestfs_umount_local".
You may call this from a different thread than the one which called
"guestfs_mount_local", subject to the usual rules for threads and
libguestfs (see "MULTIPLE HANDLES AND MULTIPLE THREADS" in
guestfs(3)).
See "MOUNT LOCAL" in
guestfs(3) for full documentation.
This function returns 0 on success or -1 on error.
(Added in 1.17.22)
guestfs_mount_loop¶
int
guestfs_mount_loop (guestfs_h *g,
const char *file,
const char *mountpoint);
This command lets you mount "file" (a filesystem image in a file) on a
mount point. It is entirely equivalent to the command "mount -o loop file
mountpoint".
This function returns 0 on success or -1 on error.
(Added in 1.0.54)
guestfs_mount_options¶
int
guestfs_mount_options (guestfs_h *g,
const char *options,
const char *device,
const char *mountpoint);
This is the same as the "guestfs_mount" command, but it allows you to
set the mount options as for the
mount(8) -o flag.
If the "options" parameter is an empty string, then no options are
passed (all options default to whatever the filesystem uses).
This function returns 0 on success or -1 on error.
(Added in 1.0.10)
guestfs_mount_ro¶
int
guestfs_mount_ro (guestfs_h *g,
const char *device,
const char *mountpoint);
This is the same as the "guestfs_mount" command, but it mounts the
filesystem with the read-only (
-o ro) flag.
This function returns 0 on success or -1 on error.
(Added in 1.0.10)
guestfs_mount_vfs¶
int
guestfs_mount_vfs (guestfs_h *g,
const char *options,
const char *vfstype,
const char *device,
const char *mountpoint);
This is the same as the "guestfs_mount" command, but it allows you to
set both the mount options and the vfstype as for the
mount(8)
-o and
-t flags.
This function returns 0 on success or -1 on error.
(Added in 1.0.10)
guestfs_mountpoints¶
char **
guestfs_mountpoints (guestfs_h *g);
This call is similar to "guestfs_mounts". That call returns a list of
devices. This one returns a hash table (map) of device name to directory where
the device is mounted.
This function returns a NULL-terminated array of strings, or NULL if there was
an error. The array of strings will always have length "2n+1", where
"n" keys and values alternate, followed by the trailing NULL entry.
The caller must free the strings and the array after use.
(Added in 1.0.62)
guestfs_mounts¶
char **
guestfs_mounts (guestfs_h *g);
This returns the list of currently mounted filesystems. It returns the list of
devices (eg. "/dev/sda1", "/dev/VG/LV").
Some internal mounts are not shown.
See also: "guestfs_mountpoints"
This function returns a NULL-terminated array of strings (like
environ(3)), or NULL if there was an error.
The caller must free the
strings and the array after use.
(Added in 0.8)
guestfs_mv¶
int
guestfs_mv (guestfs_h *g,
const char *src,
const char *dest);
This moves a file from "src" to "dest" where
"dest" is either a destination filename or destination directory.
This function returns 0 on success or -1 on error.
(Added in 1.0.18)
guestfs_ntfs_3g_probe¶
int
guestfs_ntfs_3g_probe (guestfs_h *g,
int rw,
const char *device);
This command runs the
ntfs-3g.probe(8) command which probes an NTFS
"device" for mountability. (Not all NTFS volumes can be mounted
read-write, and some cannot be mounted at all).
"rw" is a boolean flag. Set it to true if you want to test if the
volume can be mounted read-write. Set it to false if you want to test if the
volume can be mounted read-only.
The return value is an integer which 0 if the operation would succeed, or some
non-zero value documented in the
ntfs-3g.probe(8) manual page.
On error this function returns -1.
(Added in 1.0.43)
guestfs_ntfsclone_in¶
int
guestfs_ntfsclone_in (guestfs_h *g,
const char *backupfile,
const char *device);
Restore the "backupfile" (from a previous call to
"guestfs_ntfsclone_out") to "device", overwriting any
existing contents of this device.
This function returns 0 on success or -1 on error.
(Added in 1.17.9)
guestfs_ntfsclone_out¶
int
guestfs_ntfsclone_out (guestfs_h *g,
const char *device,
const char *backupfile,
...);
You may supply a list of optional arguments to this call. Use zero or more of
the following pairs of parameters, and terminate the list with "-1"
on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_NTFSCLONE_OUT_METADATAONLY, int metadataonly,
GUESTFS_NTFSCLONE_OUT_RESCUE, int rescue,
GUESTFS_NTFSCLONE_OUT_IGNOREFSCHECK, int ignorefscheck,
GUESTFS_NTFSCLONE_OUT_PRESERVETIMESTAMPS, int preservetimestamps,
GUESTFS_NTFSCLONE_OUT_FORCE, int force,
Stream the NTFS filesystem "device" to the local file
"backupfile". The format used for the backup file is a special
format used by the
ntfsclone(8) tool.
If the optional "metadataonly" flag is true, then
only the
metadata is saved, losing all the user data (this is useful for diagnosing
some filesystem problems).
The optional "rescue", "ignorefscheck",
"preservetimestamps" and "force" flags have precise
meanings detailed in the
ntfsclone(8) man page.
Use "guestfs_ntfsclone_in" to restore the file back to a libguestfs
device.
This function returns 0 on success or -1 on error.
(Added in 1.17.9)
guestfs_ntfsclone_out_va¶
int
guestfs_ntfsclone_out_va (guestfs_h *g,
const char *device,
const char *backupfile,
va_list args);
This is the "va_list variant" of "guestfs_ntfsclone_out".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_ntfsclone_out_argv¶
int
guestfs_ntfsclone_out_argv (guestfs_h *g,
const char *device,
const char *backupfile,
const struct guestfs_ntfsclone_out_argv *optargs);
This is the "argv variant" of "guestfs_ntfsclone_out".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_ntfsfix¶
int
guestfs_ntfsfix (guestfs_h *g,
const char *device,
...);
You may supply a list of optional arguments to this call. Use zero or more of
the following pairs of parameters, and terminate the list with "-1"
on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_NTFSFIX_CLEARBADSECTORS, int clearbadsectors,
This command repairs some fundamental NTFS inconsistencies, resets the NTFS
journal file, and schedules an NTFS consistency check for the first boot into
Windows.
This is
not an equivalent of Windows "chkdsk". It does
not scan the filesystem for inconsistencies.
The optional "clearbadsectors" flag clears the list of bad sectors.
This is useful after cloning a disk with bad sectors to a new disk.
This function returns 0 on success or -1 on error.
(Added in 1.17.9)
guestfs_ntfsfix_va¶
int
guestfs_ntfsfix_va (guestfs_h *g,
const char *device,
va_list args);
This is the "va_list variant" of "guestfs_ntfsfix".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_ntfsfix_argv¶
int
guestfs_ntfsfix_argv (guestfs_h *g,
const char *device,
const struct guestfs_ntfsfix_argv *optargs);
This is the "argv variant" of "guestfs_ntfsfix".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_ntfsresize¶
int
guestfs_ntfsresize (guestfs_h *g,
const char *device);
This function is deprecated. In new code, use the
"guestfs_ntfsresize_opts" call instead.
Deprecated functions will not be removed from the API, but the fact that they
are deprecated indicates that there are problems with correct use of these
functions.
This command resizes an NTFS filesystem, expanding or shrinking it to the size
of the underlying device.
Note: After the resize operation, the filesystem is marked as requiring a
consistency check (for safety). You have to boot into Windows to perform this
check and clear this condition. Furthermore, ntfsresize refuses to resize
filesystems which have been marked in this way. So in effect it is not
possible to call ntfsresize multiple times on a single filesystem without
booting into Windows between each resize.
See also
ntfsresize(8).
This function returns 0 on success or -1 on error.
(Added in 1.3.2)
guestfs_ntfsresize_opts¶
int
guestfs_ntfsresize_opts (guestfs_h *g,
const char *device,
...);
You may supply a list of optional arguments to this call. Use zero or more of
the following pairs of parameters, and terminate the list with "-1"
on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_NTFSRESIZE_OPTS_SIZE, int64_t size,
GUESTFS_NTFSRESIZE_OPTS_FORCE, int force,
This command resizes an NTFS filesystem, expanding or shrinking it to the size
of the underlying device.
The optional parameters are:
- "size"
- The new size (in bytes) of the filesystem. If omitted, the
filesystem is resized to fit the container (eg. partition).
- "force"
- If this option is true, then force the resize of the
filesystem even if the filesystem is marked as requiring a consistency
check.
After the resize operation, the filesystem is always marked as requiring a
consistency check (for safety). You have to boot into Windows to perform
this check and clear this condition. If you don't set the
"force" option then it is not possible to call
"guestfs_ntfsresize_opts" multiple times on a single filesystem
without booting into Windows between each resize.
See also
ntfsresize(8).
This function returns 0 on success or -1 on error.
(Added in 1.11.15)
guestfs_ntfsresize_opts_va¶
int
guestfs_ntfsresize_opts_va (guestfs_h *g,
const char *device,
va_list args);
This is the "va_list variant" of "guestfs_ntfsresize_opts".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_ntfsresize_opts_argv¶
int
guestfs_ntfsresize_opts_argv (guestfs_h *g,
const char *device,
const struct guestfs_ntfsresize_opts_argv *optargs);
This is the "argv variant" of "guestfs_ntfsresize_opts".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_ntfsresize_size¶
int
guestfs_ntfsresize_size (guestfs_h *g,
const char *device,
int64_t size);
This function is deprecated. In new code, use the
"guestfs_ntfsresize_opts" call instead.
Deprecated functions will not be removed from the API, but the fact that they
are deprecated indicates that there are problems with correct use of these
functions.
This command is the same as "guestfs_ntfsresize" except that it allows
you to specify the new size (in bytes) explicitly.
This function returns 0 on success or -1 on error.
(Added in 1.3.14)
guestfs_part_add¶
int
guestfs_part_add (guestfs_h *g,
const char *device,
const char *prlogex,
int64_t startsect,
int64_t endsect);
This command adds a partition to "device". If there is no partition
table on the device, call "guestfs_part_init" first.
The "prlogex" parameter is the type of partition. Normally you should
pass "p" or "primary" here, but MBR partition tables also
support "l" (or "logical") and "e" (or
"extended") partition types.
"startsect" and "endsect" are the start and end of the
partition in
sectors. "endsect" may be negative, which means
it counts backwards from the end of the disk ("-1" is the last
sector).
Creating a partition which covers the whole disk is not so easy. Use
"guestfs_part_disk" to do that.
This function returns 0 on success or -1 on error.
(Added in 1.0.78)
guestfs_part_del¶
int
guestfs_part_del (guestfs_h *g,
const char *device,
int partnum);
This command deletes the partition numbered "partnum" on
"device".
Note that in the case of MBR partitioning, deleting an extended partition also
deletes any logical partitions it contains.
This function returns 0 on success or -1 on error.
(Added in 1.3.2)
guestfs_part_disk¶
int
guestfs_part_disk (guestfs_h *g,
const char *device,
const char *parttype);
This command is simply a combination of "guestfs_part_init" followed
by "guestfs_part_add" to create a single primary partition covering
the whole disk.
"parttype" is the partition table type, usually "mbr" or
"gpt", but other possible values are described in
"guestfs_part_init".
This function returns 0 on success or -1 on error.
(Added in 1.0.78)
guestfs_part_get_bootable¶
int
guestfs_part_get_bootable (guestfs_h *g,
const char *device,
int partnum);
This command returns true if the partition "partnum" on
"device" has the bootable flag set.
See also "guestfs_part_set_bootable".
This function returns a C truth value on success or -1 on error.
(Added in 1.3.2)
guestfs_part_get_mbr_id¶
int
guestfs_part_get_mbr_id (guestfs_h *g,
const char *device,
int partnum);
Returns the MBR type byte (also known as the ID byte) from the numbered
partition "partnum".
Note that only MBR (old DOS-style) partitions have type bytes. You will get
undefined results for other partition table types (see
"guestfs_part_get_parttype").
On error this function returns -1.
(Added in 1.3.2)
guestfs_part_get_parttype¶
char *
guestfs_part_get_parttype (guestfs_h *g,
const char *device);
This command examines the partition table on "device" and returns the
partition table type (format) being used.
Common return values include: "msdos" (a DOS/Windows style MBR
partition table), "gpt" (a GPT/EFI-style partition table). Other
values are possible, although unusual. See "guestfs_part_init" for a
full list.
This function returns a string, or NULL on error.
The caller must free the
returned string after use.
(Added in 1.0.78)
guestfs_part_init¶
int
guestfs_part_init (guestfs_h *g,
const char *device,
const char *parttype);
This creates an empty partition table on "device" of one of the
partition types listed below. Usually "parttype" should be either
"msdos" or "gpt" (for large disks).
Initially there are no partitions. Following this, you should call
"guestfs_part_add" for each partition required.
Possible values for "parttype" are:
- efi
- gpt
- Intel EFI / GPT partition table.
This is recommended for >= 2 TB partitions that will be accessed from
Linux and Intel-based Mac OS X. It also has limited backwards
compatibility with the "mbr" format.
- mbr
- msdos
- The standard PC "Master Boot Record" (MBR) format
used by MS-DOS and Windows. This partition type will only work for
device sizes up to 2 TB. For large disks we recommend using
"gpt".
Other partition table types that may work but are not supported include:
- aix
- AIX disk labels.
- amiga
- rdb
- Amiga "Rigid Disk Block" format.
- bsd
- BSD disk labels.
- dasd
- DASD, used on IBM mainframes.
- dvh
- MIPS/SGI volumes.
- mac
- Old Mac partition format. Modern Macs use
"gpt".
- pc98
- NEC PC-98 format, common in Japan apparently.
- sun
- Sun disk labels.
This function returns 0 on success or -1 on error.
(Added in 1.0.78)
guestfs_part_list¶
struct guestfs_partition_list *
guestfs_part_list (guestfs_h *g,
const char *device);
This command parses the partition table on "device" and returns the
list of partitions found.
The fields in the returned structure are:
- part_num
- Partition number, counting from 1.
- part_start
- Start of the partition in bytes. To get sectors you
have to divide by the device's sector size, see
"guestfs_blockdev_getss".
- part_end
- End of the partition in bytes.
- part_size
- Size of the partition in bytes.
This function returns a "struct guestfs_partition_list *", or NULL if
there was an error.
The caller must call
"guestfs_free_partition_list" after use.
(Added in 1.0.78)
guestfs_part_set_bootable¶
int
guestfs_part_set_bootable (guestfs_h *g,
const char *device,
int partnum,
int bootable);
This sets the bootable flag on partition numbered "partnum" on device
"device". Note that partitions are numbered from 1.
The bootable flag is used by some operating systems (notably Windows) to
determine which partition to boot from. It is by no means universally
recognized.
This function returns 0 on success or -1 on error.
(Added in 1.0.78)
guestfs_part_set_mbr_id¶
int
guestfs_part_set_mbr_id (guestfs_h *g,
const char *device,
int partnum,
int idbyte);
Sets the MBR type byte (also known as the ID byte) of the numbered partition
"partnum" to "idbyte". Note that the type bytes quoted in
most documentation are in fact hexadecimal numbers, but usually documented
without any leading "0x" which might be confusing.
Note that only MBR (old DOS-style) partitions have type bytes. You will get
undefined results for other partition table types (see
"guestfs_part_get_parttype").
This function returns 0 on success or -1 on error.
(Added in 1.3.2)
guestfs_part_set_name¶
int
guestfs_part_set_name (guestfs_h *g,
const char *device,
int partnum,
const char *name);
This sets the partition name on partition numbered "partnum" on device
"device". Note that partitions are numbered from 1.
The partition name can only be set on certain types of partition table. This
works on "gpt" but not on "mbr" partitions.
This function returns 0 on success or -1 on error.
(Added in 1.0.78)
guestfs_part_to_dev¶
char *
guestfs_part_to_dev (guestfs_h *g,
const char *partition);
This function takes a partition name (eg. "/dev/sdb1") and removes the
partition number, returning the device name (eg. "/dev/sdb").
The named partition must exist, for example as a string returned from
"guestfs_list_partitions".
See also "guestfs_part_to_partnum".
This function returns a string, or NULL on error.
The caller must free the
returned string after use.
(Added in 1.5.15)
guestfs_part_to_partnum¶
int
guestfs_part_to_partnum (guestfs_h *g,
const char *partition);
This function takes a partition name (eg. "/dev/sdb1") and returns the
partition number (eg. 1).
The named partition must exist, for example as a string returned from
"guestfs_list_partitions".
See also "guestfs_part_to_dev".
On error this function returns -1.
(Added in 1.13.25)
guestfs_ping_daemon¶
int
guestfs_ping_daemon (guestfs_h *g);
This is a test probe into the guestfs daemon running inside the qemu subprocess.
Calling this function checks that the daemon responds to the ping message,
without affecting the daemon or attached block device(s) in any other way.
This function returns 0 on success or -1 on error.
(Added in 1.0.18)
guestfs_pread¶
char *
guestfs_pread (guestfs_h *g,
const char *path,
int count,
int64_t offset,
size_t *size_r);
This command lets you read part of a file. It reads "count" bytes of
the file, starting at "offset", from file "path".
This may read fewer bytes than requested. For further details see the
pread(2) system call.
See also "guestfs_pwrite", "guestfs_pread_device".
This function returns a buffer, or NULL on error. The size of the returned
buffer is written to *size_r.
The caller must free the returned buffer
after use.
Because of the message protocol, there is a transfer limit of somewhere between
2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
(Added in 1.0.77)
guestfs_pread_device¶
char *
guestfs_pread_device (guestfs_h *g,
const char *device,
int count,
int64_t offset,
size_t *size_r);
This command lets you read part of a file. It reads "count" bytes of
"device", starting at "offset".
This may read fewer bytes than requested. For further details see the
pread(2) system call.
See also "guestfs_pread".
This function returns a buffer, or NULL on error. The size of the returned
buffer is written to *size_r.
The caller must free the returned buffer
after use.
Because of the message protocol, there is a transfer limit of somewhere between
2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
(Added in 1.5.21)
guestfs_pvcreate¶
int
guestfs_pvcreate (guestfs_h *g,
const char *device);
This creates an LVM physical volume on the named "device", where
"device" should usually be a partition name such as
"/dev/sda1".
This function returns 0 on success or -1 on error.
(Added in 0.8)
guestfs_pvremove¶
int
guestfs_pvremove (guestfs_h *g,
const char *device);
This wipes a physical volume "device" so that LVM will no longer
recognise it.
The implementation uses the "pvremove" command which refuses to wipe
physical volumes that contain any volume groups, so you have to remove those
first.
This function returns 0 on success or -1 on error.
(Added in 1.0.13)
guestfs_pvresize¶
int
guestfs_pvresize (guestfs_h *g,
const char *device);
This resizes (expands or shrinks) an existing LVM physical volume to match the
new size of the underlying device.
This function returns 0 on success or -1 on error.
(Added in 1.0.26)
guestfs_pvresize_size¶
int
guestfs_pvresize_size (guestfs_h *g,
const char *device,
int64_t size);
This command is the same as "guestfs_pvresize" except that it allows
you to specify the new size (in bytes) explicitly.
This function returns 0 on success or -1 on error.
(Added in 1.3.14)
guestfs_pvs¶
char **
guestfs_pvs (guestfs_h *g);
List all the physical volumes detected. This is the equivalent of the
pvs(8) command.
This returns a list of just the device names that contain PVs (eg.
"/dev/sda2").
See also "guestfs_pvs_full".
This function returns a NULL-terminated array of strings (like
environ(3)), or NULL if there was an error.
The caller must free the
strings and the array after use.
(Added in 0.4)
guestfs_pvs_full¶
struct guestfs_lvm_pv_list *
guestfs_pvs_full (guestfs_h *g);
List all the physical volumes detected. This is the equivalent of the
pvs(8) command. The "full" version includes all fields.
This function returns a "struct guestfs_lvm_pv_list *", or NULL if
there was an error.
The caller must call
"guestfs_free_lvm_pv_list" after use.
(Added in 0.4)
guestfs_pvuuid¶
char *
guestfs_pvuuid (guestfs_h *g,
const char *device);
This command returns the UUID of the LVM PV "device".
This function returns a string, or NULL on error.
The caller must free the
returned string after use.
(Added in 1.0.87)
guestfs_pwrite¶
int
guestfs_pwrite (guestfs_h *g,
const char *path,
const char *content,
size_t content_size,
int64_t offset);
This command writes to part of a file. It writes the data buffer
"content" to the file "path" starting at offset
"offset".
This command implements the
pwrite(2) system call, and like that system
call it may not write the full data requested. The return value is the number
of bytes that were actually written to the file. This could even be 0,
although short writes are unlikely for regular files in ordinary
circumstances.
See also "guestfs_pread", "guestfs_pwrite_device".
On error this function returns -1.
Because of the message protocol, there is a transfer limit of somewhere between
2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
(Added in 1.3.14)
guestfs_pwrite_device¶
int
guestfs_pwrite_device (guestfs_h *g,
const char *device,
const char *content,
size_t content_size,
int64_t offset);
This command writes to part of a device. It writes the data buffer
"content" to "device" starting at offset
"offset".
This command implements the
pwrite(2) system call, and like that system
call it may not write the full data requested (although short writes to disk
devices and partitions are probably impossible with standard Linux kernels).
See also "guestfs_pwrite".
On error this function returns -1.
Because of the message protocol, there is a transfer limit of somewhere between
2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
(Added in 1.5.20)
guestfs_read_file¶
char *
guestfs_read_file (guestfs_h *g,
const char *path,
size_t *size_r);
This calls returns the contents of the file "path" as a buffer.
Unlike "guestfs_cat", this function can correctly handle files that
contain embedded ASCII NUL characters. However unlike
"guestfs_download", this function is limited in the total size of
file that can be handled.
This function returns a buffer, or NULL on error. The size of the returned
buffer is written to *size_r.
The caller must free the returned buffer
after use.
Because of the message protocol, there is a transfer limit of somewhere between
2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
(Added in 1.0.63)
guestfs_read_lines¶
char **
guestfs_read_lines (guestfs_h *g,
const char *path);
Return the contents of the file named "path".
The file contents are returned as a list of lines. Trailing "LF" and
"CRLF" character sequences are
not returned.
Note that this function cannot correctly handle binary files (specifically,
files containing "\0" character which is treated as end of line).
For those you need to use the "guestfs_read_file" function which has
a more complex interface.
This function returns a NULL-terminated array of strings (like
environ(3)), or NULL if there was an error.
The caller must free the
strings and the array after use.
(Added in 0.7)
guestfs_readdir¶
struct guestfs_dirent_list *
guestfs_readdir (guestfs_h *g,
const char *dir);
This returns the list of directory entries in directory "dir".
All entries in the directory are returned, including "." and
"..". The entries are
not sorted, but returned in the same
order as the underlying filesystem.
Also this call returns basic file type information about each file. The
"ftyp" field will contain one of the following characters:
- 'b'
- Block special
- 'c'
- Char special
- 'd'
- Directory
- 'f'
- FIFO (named pipe)
- 'l'
- Symbolic link
- 'r'
- Regular file
- 's'
- Socket
- 'u'
- Unknown file type
- '?'
- The readdir(3) call returned a "d_type"
field with an unexpected value
This function is primarily intended for use by programs. To get a simple list of
names, use "guestfs_ls". To get a printable directory for human
consumption, use "guestfs_ll".
This function returns a "struct guestfs_dirent_list *", or NULL if
there was an error.
The caller must call
"guestfs_free_dirent_list" after use.
(Added in 1.0.55)
guestfs_readlink¶
char *
guestfs_readlink (guestfs_h *g,
const char *path);
This command reads the target of a symbolic link.
This function returns a string, or NULL on error.
The caller must free the
returned string after use.
(Added in 1.0.66)
guestfs_readlinklist¶
char **
guestfs_readlinklist (guestfs_h *g,
const char *path,
char *const *names);
This call allows you to do a "readlink" operation on multiple files,
where all files are in the directory "path". "names" is
the list of files from this directory.
On return you get a list of strings, with a one-to-one correspondence to the
"names" list. Each string is the value of the symbolic link.
If the
readlink(2) operation fails on any name, then the corresponding result
string is the empty string "". However the whole operation is
completed even if there were
readlink(2) errors, and so you can call this
function with names where you don't know if they are symbolic links already
(albeit slightly less efficient).
This call is intended for programs that want to efficiently list a directory
contents without making many round-trips. Very long directory listings might
cause the protocol message size to be exceeded, causing this call to fail. The
caller must split up such requests into smaller groups of names.
This function returns a NULL-terminated array of strings (like
environ(3)), or NULL if there was an error.
The caller must free the
strings and the array after use.
(Added in 1.0.77)
guestfs_realpath¶
char *
guestfs_realpath (guestfs_h *g,
const char *path);
Return the canonicalized absolute pathname of "path". The returned
path has no ".", ".." or symbolic link path elements.
This function returns a string, or NULL on error.
The caller must free the
returned string after use.
(Added in 1.0.66)
guestfs_removexattr¶
int
guestfs_removexattr (guestfs_h *g,
const char *xattr,
const char *path);
This call removes the extended attribute named "xattr" of the file
"path".
See also: "guestfs_lremovexattr",
attr(5).
This function returns 0 on success or -1 on error.
(Added in 1.0.59)
guestfs_resize2fs¶
int
guestfs_resize2fs (guestfs_h *g,
const char *device);
This resizes an ext2, ext3 or ext4 filesystem to match the size of the
underlying device.
See also "RESIZE2FS ERRORS" in
guestfs(3).
This function returns 0 on success or -1 on error.
(Added in 1.0.27)
guestfs_resize2fs_M¶
int
guestfs_resize2fs_M (guestfs_h *g,
const char *device);
This command is the same as "guestfs_resize2fs", but the filesystem is
resized to its minimum size. This works like the
-M option to the
"resize2fs" command.
To get the resulting size of the filesystem you should call
"guestfs_tune2fs_l" and read the "Block size" and
"Block count" values. These two numbers, multiplied together, give
the resulting size of the minimal filesystem in bytes.
See also "RESIZE2FS ERRORS" in
guestfs(3).
This function returns 0 on success or -1 on error.
(Added in 1.9.4)
guestfs_resize2fs_size¶
int
guestfs_resize2fs_size (guestfs_h *g,
const char *device,
int64_t size);
This command is the same as "guestfs_resize2fs" except that it allows
you to specify the new size (in bytes) explicitly.
See also "RESIZE2FS ERRORS" in
guestfs(3).
This function returns 0 on success or -1 on error.
(Added in 1.3.14)
guestfs_rm¶
int
guestfs_rm (guestfs_h *g,
const char *path);
Remove the single file "path".
This function returns 0 on success or -1 on error.
(Added in 0.8)
guestfs_rm_rf¶
int
guestfs_rm_rf (guestfs_h *g,
const char *path);
Remove the file or directory "path", recursively removing the contents
if its a directory. This is like the "rm -rf" shell command.
This function returns 0 on success or -1 on error.
(Added in 0.8)
guestfs_rmdir¶
int
guestfs_rmdir (guestfs_h *g,
const char *path);
Remove the single directory "path".
This function returns 0 on success or -1 on error.
(Added in 0.8)
guestfs_rmmountpoint¶
int
guestfs_rmmountpoint (guestfs_h *g,
const char *exemptpath);
This calls removes a mountpoint that was previously created with
"guestfs_mkmountpoint". See "guestfs_mkmountpoint" for
full details.
This function returns 0 on success or -1 on error.
(Added in 1.0.62)
guestfs_scrub_device¶
int
guestfs_scrub_device (guestfs_h *g,
const char *device);
This command writes patterns over "device" to make data retrieval more
difficult.
It is an interface to the
scrub(1) program. See that manual page for more
details.
This function returns 0 on success or -1 on error.
(Added in 1.0.52)
guestfs_scrub_file¶
int
guestfs_scrub_file (guestfs_h *g,
const char *file);
This command writes patterns over a file to make data retrieval more difficult.
The file is
removed after scrubbing.
It is an interface to the
scrub(1) program. See that manual page for more
details.
This function returns 0 on success or -1 on error.
(Added in 1.0.52)
guestfs_scrub_freespace¶
int
guestfs_scrub_freespace (guestfs_h *g,
const char *dir);
This command creates the directory "dir" and then fills it with files
until the filesystem is full, and scrubs the files as for
"guestfs_scrub_file", and deletes them. The intention is to scrub
any free space on the partition containing "dir".
It is an interface to the
scrub(1) program. See that manual page for more
details.
This function returns 0 on success or -1 on error.
(Added in 1.0.52)
guestfs_set_append¶
int
guestfs_set_append (guestfs_h *g,
const char *append);
This function is used to add additional options to the guest kernel command
line.
The default is "NULL" unless overridden by setting
"LIBGUESTFS_APPEND" environment variable.
Setting "append" to "NULL" means
no additional
options are passed (libguestfs always adds a few of its own).
This function returns 0 on success or -1 on error.
(Added in 1.0.26)
guestfs_set_attach_method¶
int
guestfs_set_attach_method (guestfs_h *g,
const char *attachmethod);
Set the method that libguestfs uses to connect to the back end guestfsd daemon.
Possible methods are:
- "appliance"
- Launch an appliance and connect to it. This is the ordinary
method and the default.
- "unix:path"
- Connect to the Unix domain socket path.
This method lets you connect to an existing daemon or (using virtio-serial)
to a live guest. For more information, see "ATTACHING TO RUNNING
DAEMONS" in guestfs(3).
This function returns 0 on success or -1 on error.
(Added in 1.9.8)
guestfs_set_autosync¶
int
guestfs_set_autosync (guestfs_h *g,
int autosync);
If "autosync" is true, this enables autosync. Libguestfs will make a
best effort attempt to make filesystems consistent and synchronized when the
handle is closed (also if the program exits without closing handles).
This is enabled by default (since libguestfs 1.5.24, previously it was disabled
by default).
This function returns 0 on success or -1 on error.
(Added in 0.3)
guestfs_set_direct¶
int
guestfs_set_direct (guestfs_h *g,
int direct);
If the direct appliance mode flag is enabled, then stdin and stdout are passed
directly through to the appliance once it is launched.
One consequence of this is that log messages aren't caught by the library and
handled by "guestfs_set_log_message_callback", but go straight to
stdout.
You probably don't want to use this unless you know what you are doing.
The default is disabled.
This function returns 0 on success or -1 on error.
(Added in 1.0.72)
guestfs_set_e2attrs¶
int
guestfs_set_e2attrs (guestfs_h *g,
const char *file,
const char *attrs,
...);
You may supply a list of optional arguments to this call. Use zero or more of
the following pairs of parameters, and terminate the list with "-1"
on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_SET_E2ATTRS_CLEAR, int clear,
This sets or clears the file attributes "attrs" associated with the
inode "file".
"attrs" is a string of characters representing file attributes. See
"guestfs_get_e2attrs" for a list of possible attributes. Not all
attributes can be changed.
If optional boolean "clear" is not present or false, then the
"attrs" listed are set in the inode.
If "clear" is true, then the "attrs" listed are cleared in
the inode.
In both cases, other attributes not present in the "attrs" string are
left unchanged.
These attributes are only present when the file is located on an ext2/3/4
filesystem. Using this call on other filesystem types will result in an error.
This function returns 0 on success or -1 on error.
(Added in 1.17.31)
guestfs_set_e2attrs_va¶
int
guestfs_set_e2attrs_va (guestfs_h *g,
const char *file,
const char *attrs,
va_list args);
This is the "va_list variant" of "guestfs_set_e2attrs".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_set_e2attrs_argv¶
int
guestfs_set_e2attrs_argv (guestfs_h *g,
const char *file,
const char *attrs,
const struct guestfs_set_e2attrs_argv *optargs);
This is the "argv variant" of "guestfs_set_e2attrs".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_set_e2generation¶
int
guestfs_set_e2generation (guestfs_h *g,
const char *file,
int64_t generation);
This sets the ext2 file generation of a file.
See "guestfs_get_e2generation".
This function returns 0 on success or -1 on error.
(Added in 1.17.31)
guestfs_set_e2label¶
int
guestfs_set_e2label (guestfs_h *g,
const char *device,
const char *label);
This function is deprecated. In new code, use the
"guestfs_set_label" call instead.
Deprecated functions will not be removed from the API, but the fact that they
are deprecated indicates that there are problems with correct use of these
functions.
This sets the ext2/3/4 filesystem label of the filesystem on "device"
to "label". Filesystem labels are limited to 16 characters.
You can use either "guestfs_tune2fs_l" or
"guestfs_get_e2label" to return the existing label on a filesystem.
This function returns 0 on success or -1 on error.
(Added in 1.0.15)
guestfs_set_e2uuid¶
int
guestfs_set_e2uuid (guestfs_h *g,
const char *device,
const char *uuid);
This sets the ext2/3/4 filesystem UUID of the filesystem on "device"
to "uuid". The format of the UUID and alternatives such as
"clear", "random" and "time" are described in
the
tune2fs(8) manpage.
You can use either "guestfs_tune2fs_l" or
"guestfs_get_e2uuid" to return the existing UUID of a filesystem.
This function returns 0 on success or -1 on error.
(Added in 1.0.15)
guestfs_set_label¶
int
guestfs_set_label (guestfs_h *g,
const char *device,
const char *label);
Set the filesystem label on "device" to "label".
Only some filesystem types support labels, and libguestfs supports setting
labels on only a subset of these.
On ext2/3/4 filesystems, labels are limited to 16 bytes.
On NTFS filesystems, labels are limited to 128 unicode characters.
To read the label on a filesystem, call "guestfs_vfs_label".
This function returns 0 on success or -1 on error.
(Added in 1.17.9)
guestfs_set_memsize¶
int
guestfs_set_memsize (guestfs_h *g,
int memsize);
This sets the memory size in megabytes allocated to the qemu subprocess. This
only has any effect if called before "guestfs_launch".
You can also change this by setting the environment variable
"LIBGUESTFS_MEMSIZE" before the handle is created.
For more information on the architecture of libguestfs, see
guestfs(3).
This function returns 0 on success or -1 on error.
(Added in 1.0.55)
guestfs_set_network¶
int
guestfs_set_network (guestfs_h *g,
int network);
If "network" is true, then the network is enabled in the libguestfs
appliance. The default is false.
This affects whether commands are able to access the network (see "RUNNING
COMMANDS" in
guestfs(3)).
You must call this before calling "guestfs_launch", otherwise it has
no effect.
This function returns 0 on success or -1 on error.
(Added in 1.5.4)
guestfs_set_path¶
int
guestfs_set_path (guestfs_h *g,
const char *searchpath);
Set the path that libguestfs searches for kernel and initrd.img.
The default is "$libdir/guestfs" unless overridden by setting
"LIBGUESTFS_PATH" environment variable.
Setting "path" to "NULL" restores the default path.
This function returns 0 on success or -1 on error.
(Added in 0.3)
guestfs_set_pgroup¶
int
guestfs_set_pgroup (guestfs_h *g,
int pgroup);
If "pgroup" is true, child processes are placed into their own process
group.
The practical upshot of this is that signals like "SIGINT" (from users
pressing "^C") won't be received by the child process.
The default for this flag is false, because usually you want "^C" to
kill the subprocess. Guestfish sets this flag to true when used interactively,
so that "^C" can cancel long-running commands gracefully (see
"guestfs_user_cancel").
This function returns 0 on success or -1 on error.
(Added in 1.11.18)
guestfs_set_qemu¶
int
guestfs_set_qemu (guestfs_h *g,
const char *qemu);
Set the qemu binary that we will use.
The default is chosen when the library was compiled by the configure script.
You can also override this by setting the "LIBGUESTFS_QEMU"
environment variable.
Setting "qemu" to "NULL" restores the default qemu binary.
Note that you should call this function as early as possible after creating the
handle. This is because some pre-launch operations depend on testing qemu
features (by running "qemu -help"). If the qemu binary changes, we
don't retest features, and so you might see inconsistent results. Using the
environment variable "LIBGUESTFS_QEMU" is safest of all since that
picks the qemu binary at the same time as the handle is created.
This function returns 0 on success or -1 on error.
(Added in 1.0.6)
guestfs_set_recovery_proc¶
int
guestfs_set_recovery_proc (guestfs_h *g,
int recoveryproc);
If this is called with the parameter "false" then
"guestfs_launch" does not create a recovery process. The purpose of
the recovery process is to stop runaway qemu processes in the case where the
main program aborts abruptly.
This only has any effect if called before "guestfs_launch", and the
default is true.
About the only time when you would want to disable this is if the main process
will fork itself into the background ("daemonize" itself). In this
case the recovery process thinks that the main program has disappeared and so
kills qemu, which is not very helpful.
This function returns 0 on success or -1 on error.
(Added in 1.0.77)
guestfs_set_selinux¶
int
guestfs_set_selinux (guestfs_h *g,
int selinux);
This sets the selinux flag that is passed to the appliance at boot time. The
default is "selinux=0" (disabled).
Note that if SELinux is enabled, it is always in Permissive mode
("enforcing=0").
For more information on the architecture of libguestfs, see
guestfs(3).
This function returns 0 on success or -1 on error.
(Added in 1.0.67)
guestfs_set_smp¶
int
guestfs_set_smp (guestfs_h *g,
int smp);
Change the number of virtual CPUs assigned to the appliance. The default is 1.
Increasing this may improve performance, though often it has no effect.
This function must be called before "guestfs_launch".
This function returns 0 on success or -1 on error.
(Added in 1.13.15)
guestfs_set_trace¶
int
guestfs_set_trace (guestfs_h *g,
int trace);
If the command trace flag is set to 1, then libguestfs calls, parameters and
return values are traced.
If you want to trace C API calls into libguestfs (and other libraries) then
possibly a better way is to use the external
ltrace(1) command.
Command traces are disabled unless the environment variable
"LIBGUESTFS_TRACE" is defined and set to 1.
Trace messages are normally sent to "stderr", unless you register a
callback to send them somewhere else (see
"guestfs_set_event_callback").
This function returns 0 on success or -1 on error.
(Added in 1.0.69)
guestfs_set_verbose¶
int
guestfs_set_verbose (guestfs_h *g,
int verbose);
If "verbose" is true, this turns on verbose messages.
Verbose messages are disabled unless the environment variable
"LIBGUESTFS_DEBUG" is defined and set to 1.
Verbose messages are normally sent to "stderr", unless you register a
callback to send them somewhere else (see
"guestfs_set_event_callback").
This function returns 0 on success or -1 on error.
(Added in 0.3)
guestfs_setcon¶
int
guestfs_setcon (guestfs_h *g,
const char *context);
This sets the SELinux security context of the daemon to the string
"context".
See the documentation about SELINUX in
guestfs(3).
This function returns 0 on success or -1 on error.
(Added in 1.0.67)
guestfs_setxattr¶
int
guestfs_setxattr (guestfs_h *g,
const char *xattr,
const char *val,
int vallen,
const char *path);
This call sets the extended attribute named "xattr" of the file
"path" to the value "val" (of length "vallen").
The value is arbitrary 8 bit data.
See also: "guestfs_lsetxattr",
attr(5).
This function returns 0 on success or -1 on error.
(Added in 1.0.59)
guestfs_sfdisk¶
int
guestfs_sfdisk (guestfs_h *g,
const char *device,
int cyls,
int heads,
int sectors,
char *const *lines);
This function is deprecated. In new code, use the
"guestfs_part_add" call instead.
Deprecated functions will not be removed from the API, but the fact that they
are deprecated indicates that there are problems with correct use of these
functions.
This is a direct interface to the
sfdisk(8) program for creating
partitions on block devices.
"device" should be a block device, for example "/dev/sda".
"cyls", "heads" and "sectors" are the number of
cylinders, heads and sectors on the device, which are passed directly to
sfdisk as the
-C,
-H and
-S parameters. If you pass 0 for
any of these, then the corresponding parameter is omitted. Usually for 'large'
disks, you can just pass 0 for these, but for small (floppy-sized) disks,
sfdisk (or rather, the kernel) cannot work out the right geometry and you will
need to tell it.
"lines" is a list of lines that we feed to "sfdisk". For
more information refer to the
sfdisk(8) manpage.
To create a single partition occupying the whole disk, you would pass
"lines" as a single element list, when the single element being the
string "," (comma).
See also: "guestfs_sfdisk_l", "guestfs_sfdisk_N",
"guestfs_part_init"
This function returns 0 on success or -1 on error.
(Added in 0.8)
guestfs_sfdiskM¶
int
guestfs_sfdiskM (guestfs_h *g,
const char *device,
char *const *lines);
This function is deprecated. In new code, use the
"guestfs_part_add" call instead.
Deprecated functions will not be removed from the API, but the fact that they
are deprecated indicates that there are problems with correct use of these
functions.
This is a simplified interface to the "guestfs_sfdisk" command, where
partition sizes are specified in megabytes only (rounded to the nearest
cylinder) and you don't need to specify the cyls, heads and sectors parameters
which were rarely if ever used anyway.
See also: "guestfs_sfdisk", the
sfdisk(8) manpage and
"guestfs_part_disk"
This function returns 0 on success or -1 on error.
(Added in 1.0.55)
guestfs_sfdisk_N¶
int
guestfs_sfdisk_N (guestfs_h *g,
const char *device,
int partnum,
int cyls,
int heads,
int sectors,
const char *line);
This function is deprecated. In new code, use the
"guestfs_part_add" call instead.
Deprecated functions will not be removed from the API, but the fact that they
are deprecated indicates that there are problems with correct use of these
functions.
This runs
sfdisk(8) option to modify just the single partition
"n" (note: "n" counts from 1).
For other parameters, see "guestfs_sfdisk". You should usually pass 0
for the cyls/heads/sectors parameters.
See also: "guestfs_part_add"
This function returns 0 on success or -1 on error.
(Added in 1.0.26)
guestfs_sfdisk_disk_geometry¶
char *
guestfs_sfdisk_disk_geometry (guestfs_h *g,
const char *device);
This displays the disk geometry of "device" read from the partition
table. Especially in the case where the underlying block device has been
resized, this can be different from the kernel's idea of the geometry (see
"guestfs_sfdisk_kernel_geometry").
The result is in human-readable format, and not designed to be parsed.
This function returns a string, or NULL on error.
The caller must free the
returned string after use.
(Added in 1.0.26)
guestfs_sfdisk_kernel_geometry¶
char *
guestfs_sfdisk_kernel_geometry (guestfs_h *g,
const char *device);
This displays the kernel's idea of the geometry of "device".
The result is in human-readable format, and not designed to be parsed.
This function returns a string, or NULL on error.
The caller must free the
returned string after use.
(Added in 1.0.26)
guestfs_sfdisk_l¶
char *
guestfs_sfdisk_l (guestfs_h *g,
const char *device);
This function is deprecated. In new code, use the
"guestfs_part_list" call instead.
Deprecated functions will not be removed from the API, but the fact that they
are deprecated indicates that there are problems with correct use of these
functions.
This displays the partition table on "device", in the human-readable
output of the
sfdisk(8) command. It is not intended to be parsed.
See also: "guestfs_part_list"
This function returns a string, or NULL on error.
The caller must free the
returned string after use.
(Added in 1.0.26)
guestfs_sh¶
char *
guestfs_sh (guestfs_h *g,
const char *command);
This call runs a command from the guest filesystem via the guest's
"/bin/sh".
This is like "guestfs_command", but passes the command to:
/bin/sh -c "command"
Depending on the guest's shell, this usually results in wildcards being
expanded, shell expressions being interpolated and so on.
All the provisos about "guestfs_command" apply to this call.
This function returns a string, or NULL on error.
The caller must free the
returned string after use.
(Added in 1.0.50)
guestfs_sh_lines¶
char **
guestfs_sh_lines (guestfs_h *g,
const char *command);
This is the same as "guestfs_sh", but splits the result into a list of
lines.
See also: "guestfs_command_lines"
This function returns a NULL-terminated array of strings (like
environ(3)), or NULL if there was an error.
The caller must free the
strings and the array after use.
(Added in 1.0.50)
guestfs_sleep¶
int
guestfs_sleep (guestfs_h *g,
int secs);
Sleep for "secs" seconds.
This function returns 0 on success or -1 on error.
(Added in 1.0.41)
guestfs_stat¶
struct guestfs_stat *
guestfs_stat (guestfs_h *g,
const char *path);
Returns file information for the given "path".
This is the same as the
stat(2) system call.
This function returns a "struct guestfs_stat *", or NULL if there was
an error.
The caller must call "guestfs_free_stat"
after use.
(Added in 0.9.2)
guestfs_statvfs¶
struct guestfs_statvfs *
guestfs_statvfs (guestfs_h *g,
const char *path);
Returns file system statistics for any mounted file system. "path"
should be a file or directory in the mounted file system (typically it is the
mount point itself, but it doesn't need to be).
This is the same as the
statvfs(2) system call.
This function returns a "struct guestfs_statvfs *", or NULL if there
was an error.
The caller must call
"guestfs_free_statvfs" after use.
(Added in 0.9.2)
guestfs_strings¶
char **
guestfs_strings (guestfs_h *g,
const char *path);
This runs the
strings(1) command on a file and returns the list of
printable strings found.
This function returns a NULL-terminated array of strings (like
environ(3)), or NULL if there was an error.
The caller must free the
strings and the array after use.
Because of the message protocol, there is a transfer limit of somewhere between
2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
(Added in 1.0.22)
guestfs_strings_e¶
char **
guestfs_strings_e (guestfs_h *g,
const char *encoding,
const char *path);
This is like the "guestfs_strings" command, but allows you to specify
the encoding of strings that are looked for in the source file
"path".
Allowed encodings are:
- s
- Single 7-bit-byte characters like ASCII and the
ASCII-compatible parts of ISO-8859-X (this is what
"guestfs_strings" uses).
- S
- Single 8-bit-byte characters.
- b
- 16-bit big endian strings such as those encoded in UTF-16BE
or UCS-2BE.
- l (lower case letter L)
- 16-bit little endian such as UTF-16LE and UCS-2LE. This is
useful for examining binaries in Windows guests.
- B
- 32-bit big endian such as UCS-4BE.
- L
- 32-bit little endian such as UCS-4LE.
The returned strings are transcoded to UTF-8.
This function returns a NULL-terminated array of strings (like
environ(3)), or NULL if there was an error.
The caller must free the
strings and the array after use.
Because of the message protocol, there is a transfer limit of somewhere between
2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
(Added in 1.0.22)
guestfs_swapoff_device¶
int
guestfs_swapoff_device (guestfs_h *g,
const char *device);
This command disables the libguestfs appliance swap device or partition named
"device". See "guestfs_swapon_device".
This function returns 0 on success or -1 on error.
(Added in 1.0.66)
guestfs_swapoff_file¶
int
guestfs_swapoff_file (guestfs_h *g,
const char *file);
This command disables the libguestfs appliance swap on file.
This function returns 0 on success or -1 on error.
(Added in 1.0.66)
guestfs_swapoff_label¶
int
guestfs_swapoff_label (guestfs_h *g,
const char *label);
This command disables the libguestfs appliance swap on labeled swap partition.
This function returns 0 on success or -1 on error.
(Added in 1.0.66)
guestfs_swapoff_uuid¶
int
guestfs_swapoff_uuid (guestfs_h *g,
const char *uuid);
This command disables the libguestfs appliance swap partition with the given
UUID.
This function returns 0 on success or -1 on error.
(Added in 1.0.66)
guestfs_swapon_device¶
int
guestfs_swapon_device (guestfs_h *g,
const char *device);
This command enables the libguestfs appliance to use the swap device or
partition named "device". The increased memory is made available for
all commands, for example those run using "guestfs_command" or
"guestfs_sh".
Note that you should not swap to existing guest swap partitions unless you know
what you are doing. They may contain hibernation information, or other
information that the guest doesn't want you to trash. You also risk leaking
information about the host to the guest this way. Instead, attach a new host
device to the guest and swap on that.
This function returns 0 on success or -1 on error.
(Added in 1.0.66)
guestfs_swapon_file¶
int
guestfs_swapon_file (guestfs_h *g,
const char *file);
This command enables swap to a file. See "guestfs_swapon_device" for
other notes.
This function returns 0 on success or -1 on error.
(Added in 1.0.66)
guestfs_swapon_label¶
int
guestfs_swapon_label (guestfs_h *g,
const char *label);
This command enables swap to a labeled swap partition. See
"guestfs_swapon_device" for other notes.
This function returns 0 on success or -1 on error.
(Added in 1.0.66)
guestfs_swapon_uuid¶
int
guestfs_swapon_uuid (guestfs_h *g,
const char *uuid);
This command enables swap to a swap partition with the given UUID. See
"guestfs_swapon_device" for other notes.
This function returns 0 on success or -1 on error.
(Added in 1.0.66)
guestfs_sync¶
int
guestfs_sync (guestfs_h *g);
This syncs the disk, so that any writes are flushed through to the underlying
disk image.
You should always call this if you have modified a disk image, before closing
the handle.
This function returns 0 on success or -1 on error.
(Added in 0.3)
guestfs_tail¶
char **
guestfs_tail (guestfs_h *g,
const char *path);
This command returns up to the last 10 lines of a file as a list of strings.
This function returns a NULL-terminated array of strings (like
environ(3)), or NULL if there was an error.
The caller must free the
strings and the array after use.
Because of the message protocol, there is a transfer limit of somewhere between
2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
(Added in 1.0.54)
guestfs_tail_n¶
char **
guestfs_tail_n (guestfs_h *g,
int nrlines,
const char *path);
If the parameter "nrlines" is a positive number, this returns the last
"nrlines" lines of the file "path".
If the parameter "nrlines" is a negative number, this returns lines
from the file "path", starting with the "-nrlines"th line.
If the parameter "nrlines" is zero, this returns an empty list.
This function returns a NULL-terminated array of strings (like
environ(3)), or NULL if there was an error.
The caller must free the
strings and the array after use.
Because of the message protocol, there is a transfer limit of somewhere between
2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
(Added in 1.0.54)
guestfs_tar_in¶
int
guestfs_tar_in (guestfs_h *g,
const char *tarfile,
const char *directory);
This command uploads and unpacks local file "tarfile" (an
uncompressed tar file) into "directory".
To upload a compressed tarball, use "guestfs_tgz_in" or
"guestfs_txz_in".
This function returns 0 on success or -1 on error.
(Added in 1.0.3)
guestfs_tar_out¶
int
guestfs_tar_out (guestfs_h *g,
const char *directory,
const char *tarfile);
This command packs the contents of "directory" and downloads it to
local file "tarfile".
To download a compressed tarball, use "guestfs_tgz_out" or
"guestfs_txz_out".
This function returns 0 on success or -1 on error.
(Added in 1.0.3)
guestfs_tgz_in¶
int
guestfs_tgz_in (guestfs_h *g,
const char *tarball,
const char *directory);
This command uploads and unpacks local file "tarball" (a
gzip
compressed tar file) into "directory".
To upload an uncompressed tarball, use "guestfs_tar_in".
This function returns 0 on success or -1 on error.
(Added in 1.0.3)
guestfs_tgz_out¶
int
guestfs_tgz_out (guestfs_h *g,
const char *directory,
const char *tarball);
This command packs the contents of "directory" and downloads it to
local file "tarball".
To download an uncompressed tarball, use "guestfs_tar_out".
This function returns 0 on success or -1 on error.
(Added in 1.0.3)
guestfs_touch¶
int
guestfs_touch (guestfs_h *g,
const char *path);
Touch acts like the
touch(1) command. It can be used to update the
timestamps on a file, or, if the file does not exist, to create a new
zero-length file.
This command only works on regular files, and will fail on other file types such
as directories, symbolic links, block special etc.
This function returns 0 on success or -1 on error.
(Added in 0.3)
guestfs_truncate¶
int
guestfs_truncate (guestfs_h *g,
const char *path);
This command truncates "path" to a zero-length file. The file must
exist already.
This function returns 0 on success or -1 on error.
(Added in 1.0.77)
guestfs_truncate_size¶
int
guestfs_truncate_size (guestfs_h *g,
const char *path,
int64_t size);
This command truncates "path" to size "size" bytes. The file
must exist already.
If the current file size is less than "size" then the file is extended
to the required size with zero bytes. This creates a sparse file (ie. disk
blocks are not allocated for the file until you write to it). To create a
non-sparse file of zeroes, use "guestfs_fallocate64" instead.
This function returns 0 on success or -1 on error.
(Added in 1.0.77)
guestfs_tune2fs¶
int
guestfs_tune2fs (guestfs_h *g,
const char *device,
...);
You may supply a list of optional arguments to this call. Use zero or more of
the following pairs of parameters, and terminate the list with "-1"
on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_TUNE2FS_FORCE, int force,
GUESTFS_TUNE2FS_MAXMOUNTCOUNT, int maxmountcount,
GUESTFS_TUNE2FS_MOUNTCOUNT, int mountcount,
GUESTFS_TUNE2FS_ERRORBEHAVIOR, const char *errorbehavior,
GUESTFS_TUNE2FS_GROUP, int64_t group,
GUESTFS_TUNE2FS_INTERVALBETWEENCHECKS, int intervalbetweenchecks,
GUESTFS_TUNE2FS_RESERVEDBLOCKSPERCENTAGE, int reservedblockspercentage,
GUESTFS_TUNE2FS_LASTMOUNTEDDIRECTORY, const char *lastmounteddirectory,
GUESTFS_TUNE2FS_RESERVEDBLOCKSCOUNT, int64_t reservedblockscount,
GUESTFS_TUNE2FS_USER, int64_t user,
This call allows you to adjust various filesystem parameters of an
ext2/ext3/ext4 filesystem called "device".
The optional parameters are:
- "force"
- Force tune2fs to complete the operation even in the face of
errors. This is the same as the tune2fs "-f" option.
- "maxmountcount"
- Set the number of mounts after which the filesystem is
checked by e2fsck(8). If this is 0 then the number of mounts is
disregarded. This is the same as the tune2fs "-c" option.
- "mountcount"
- Set the number of times the filesystem has been mounted.
This is the same as the tune2fs "-C" option.
- "errorbehavior"
- Change the behavior of the kernel code when errors are
detected. Possible values currently are: "continue",
"remount-ro", "panic". In practice these options don't
really make any difference, particularly for write errors.
This is the same as the tune2fs "-e" option.
- "group"
- Set the group which can use reserved filesystem blocks.
This is the same as the tune2fs "-g" option except that it can
only be specified as a number.
- "intervalbetweenchecks"
- Adjust the maximal time between two filesystem checks (in
seconds). If the option is passed as 0 then time-dependent checking is
disabled.
This is the same as the tune2fs "-i" option.
- "reservedblockspercentage"
- Set the percentage of the filesystem which may only be
allocated by privileged processes. This is the same as the tune2fs
"-m" option.
- "lastmounteddirectory"
- Set the last mounted directory. This is the same as the
tune2fs "-M" option.
- "reservedblockscount" Set the number of reserved
filesystem blocks. This is the same as the tune2fs "-r"
option.
- "user"
- Set the user who can use the reserved filesystem blocks.
This is the same as the tune2fs "-u" option except that it can
only be specified as a number.
To get the current values of filesystem parameters, see
"guestfs_tune2fs_l". For precise details of how tune2fs works, see
the
tune2fs(8) man page.
This function returns 0 on success or -1 on error.
(Added in 1.15.4)
guestfs_tune2fs_va¶
int
guestfs_tune2fs_va (guestfs_h *g,
const char *device,
va_list args);
This is the "va_list variant" of "guestfs_tune2fs".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_tune2fs_argv¶
int
guestfs_tune2fs_argv (guestfs_h *g,
const char *device,
const struct guestfs_tune2fs_argv *optargs);
This is the "argv variant" of "guestfs_tune2fs".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_tune2fs_l¶
char **
guestfs_tune2fs_l (guestfs_h *g,
const char *device);
This returns the contents of the ext2, ext3 or ext4 filesystem superblock on
"device".
It is the same as running "tune2fs -l device". See
tune2fs(8)
manpage for more details. The list of fields returned isn't clearly defined,
and depends on both the version of "tune2fs" that libguestfs was
built against, and the filesystem itself.
This function returns a NULL-terminated array of strings, or NULL if there was
an error. The array of strings will always have length "2n+1", where
"n" keys and values alternate, followed by the trailing NULL entry.
The caller must free the strings and the array after use.
(Added in 0.9.2)
guestfs_txz_in¶
int
guestfs_txz_in (guestfs_h *g,
const char *tarball,
const char *directory);
This command uploads and unpacks local file "tarball" (an
xz
compressed tar file) into "directory".
This function returns 0 on success or -1 on error.
(Added in 1.3.2)
guestfs_txz_out¶
int
guestfs_txz_out (guestfs_h *g,
const char *directory,
const char *tarball);
This command packs the contents of "directory" and downloads it to
local file "tarball" (as an xz compressed tar archive).
This function returns 0 on success or -1 on error.
(Added in 1.3.2)
guestfs_umask¶
int
guestfs_umask (guestfs_h *g,
int mask);
This function sets the mask used for creating new files and device nodes to
"mask & 0777".
Typical umask values would be 022 which creates new files with permissions like
"-rw-r--r--" or "-rwxr-xr-x", and 002 which creates new
files with permissions like "-rw-rw-r--" or "-rwxrwxr-x".
The default umask is 022. This is important because it means that directories
and device nodes will be created with 0644 or 0755 mode even if you specify
0777.
See also "guestfs_get_umask",
umask(2),
"guestfs_mknod", "guestfs_mkdir".
This call returns the previous umask.
On error this function returns -1.
(Added in 1.0.55)
guestfs_umount¶
int
guestfs_umount (guestfs_h *g,
const char *pathordevice);
This unmounts the given filesystem. The filesystem may be specified either by
its mountpoint (path) or the device which contains the filesystem.
This function returns 0 on success or -1 on error.
(Added in 0.8)
guestfs_umount_all¶
int
guestfs_umount_all (guestfs_h *g);
This unmounts all mounted filesystems.
Some internal mounts are not unmounted by this call.
This function returns 0 on success or -1 on error.
(Added in 0.8)
guestfs_umount_local¶
int
guestfs_umount_local (guestfs_h *g,
...);
You may supply a list of optional arguments to this call. Use zero or more of
the following pairs of parameters, and terminate the list with "-1"
on its own. See "CALLS WITH OPTIONAL ARGUMENTS".
GUESTFS_UMOUNT_LOCAL_RETRY, int retry,
If libguestfs is exporting the filesystem on a local mountpoint, then this
unmounts it.
See "MOUNT LOCAL" in
guestfs(3) for full documentation.
This function returns 0 on success or -1 on error.
(Added in 1.17.22)
guestfs_umount_local_va¶
int
guestfs_umount_local_va (guestfs_h *g,
va_list args);
This is the "va_list variant" of "guestfs_umount_local".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_umount_local_argv¶
int
guestfs_umount_local_argv (guestfs_h *g,
const struct guestfs_umount_local_argv *optargs);
This is the "argv variant" of "guestfs_umount_local".
See "CALLS WITH OPTIONAL ARGUMENTS".
guestfs_upload¶
int
guestfs_upload (guestfs_h *g,
const char *filename,
const char *remotefilename);
Upload local file "filename" to "remotefilename" on the
filesystem.
"filename" can also be a named pipe.
See also "guestfs_download".
This function returns 0 on success or -1 on error.
This long-running command can generate progress notification messages so that
the caller can display a progress bar or indicator. To receive these messages,
the caller must register a progress event callback. See
"GUESTFS_EVENT_PROGRESS" in
guestfs(3).
(Added in 1.0.2)
guestfs_upload_offset¶
int
guestfs_upload_offset (guestfs_h *g,
const char *filename,
const char *remotefilename,
int64_t offset);
Upload local file "filename" to "remotefilename" on the
filesystem.
"remotefilename" is overwritten starting at the byte
"offset" specified. The intention is to overwrite parts of existing
files or devices, although if a non-existant file is specified then it is
created with a "hole" before "offset". The size of the
data written is implicit in the size of the source "filename".
Note that there is no limit on the amount of data that can be uploaded with this
call, unlike with "guestfs_pwrite", and this call always writes the
full amount unless an error occurs.
See also "guestfs_upload", "guestfs_pwrite".
This function returns 0 on success or -1 on error.
This long-running command can generate progress notification messages so that
the caller can display a progress bar or indicator. To receive these messages,
the caller must register a progress event callback. See
"GUESTFS_EVENT_PROGRESS" in
guestfs(3).
(Added in 1.5.17)
guestfs_utimens¶
int
guestfs_utimens (guestfs_h *g,
const char *path,
int64_t atsecs,
int64_t atnsecs,
int64_t mtsecs,
int64_t mtnsecs);
This command sets the timestamps of a file with nanosecond precision.
"atsecs, atnsecs" are the last access time (atime) in secs and
nanoseconds from the epoch.
"mtsecs, mtnsecs" are the last modification time (mtime) in secs and
nanoseconds from the epoch.
If the *nsecs field contains the special value "-1" then the
corresponding timestamp is set to the current time. (The *secs field is
ignored in this case).
If the *nsecs field contains the special value "-2" then the
corresponding timestamp is left unchanged. (The *secs field is ignored in this
case).
This function returns 0 on success or -1 on error.
(Added in 1.0.77)
guestfs_version¶
struct guestfs_version *
guestfs_version (guestfs_h *g);
Return the libguestfs version number that the program is linked against.
Note that because of dynamic linking this is not necessarily the version of
libguestfs that you compiled against. You can compile the program, and then at
runtime dynamically link against a completely different
"libguestfs.so" library.
This call was added in version 1.0.58. In previous versions of libguestfs there
was no way to get the version number. From C code you can use dynamic linker
functions to find out if this symbol exists (if it doesn't, then it's an
earlier version).
The call returns a structure with four elements. The first three
("major", "minor" and "release") are numbers and
correspond to the usual version triplet. The fourth element
("extra") is a string and is normally empty, but may be used for
distro-specific information.
To construct the original version string:
"$major.$minor.$release$extra"
See also: "LIBGUESTFS VERSION NUMBERS" in
guestfs(3).
Note: Don't use this call to test for availability of features. In
enterprise distributions we backport features from later versions into earlier
versions, making this an unreliable way to test for features. Use
"guestfs_available" instead.
This function returns a "struct guestfs_version *", or NULL if there
was an error.
The caller must call
"guestfs_free_version" after use.
(Added in 1.0.58)
guestfs_vfs_label¶
char *
guestfs_vfs_label (guestfs_h *g,
const char *device);
This returns the filesystem label of the filesystem on "device".
If the filesystem is unlabeled, this returns the empty string.
To find a filesystem from the label, use "guestfs_findfs_label".
This function returns a string, or NULL on error.
The caller must free the
returned string after use.
(Added in 1.3.18)
guestfs_vfs_type¶
char *
guestfs_vfs_type (guestfs_h *g,
const char *device);
This command gets the filesystem type corresponding to the filesystem on
"device".
For most filesystems, the result is the name of the Linux VFS module which would
be used to mount this filesystem if you mounted it without specifying the
filesystem type. For example a string such as "ext3" or
"ntfs".
This function returns a string, or NULL on error.
The caller must free the
returned string after use.
(Added in 1.0.75)
guestfs_vfs_uuid¶
char *
guestfs_vfs_uuid (guestfs_h *g,
const char *device);
This returns the filesystem UUID of the filesystem on "device".
If the filesystem does not have a UUID, this returns the empty string.
To find a filesystem from the UUID, use "guestfs_findfs_uuid".
This function returns a string, or NULL on error.
The caller must free the
returned string after use.
(Added in 1.3.18)
guestfs_vg_activate¶
int
guestfs_vg_activate (guestfs_h *g,
int activate,
char *const *volgroups);
This command activates or (if "activate" is false) deactivates all
logical volumes in the listed volume groups "volgroups".
This command is the same as running "vgchange -a y|n volgroups..."
Note that if "volgroups" is an empty list then
all volume
groups are activated or deactivated.
This function returns 0 on success or -1 on error.
(Added in 1.0.26)
guestfs_vg_activate_all¶
int
guestfs_vg_activate_all (guestfs_h *g,
int activate);
This command activates or (if "activate" is false) deactivates all
logical volumes in all volume groups.
This command is the same as running "vgchange -a y|n"
This function returns 0 on success or -1 on error.
(Added in 1.0.26)
guestfs_vgcreate¶
int
guestfs_vgcreate (guestfs_h *g,
const char *volgroup,
char *const *physvols);
This creates an LVM volume group called "volgroup" from the non-empty
list of physical volumes "physvols".
This function returns 0 on success or -1 on error.
(Added in 0.8)
guestfs_vglvuuids¶
char **
guestfs_vglvuuids (guestfs_h *g,
const char *vgname);
Given a VG called "vgname", this returns the UUIDs of all the logical
volumes created in this volume group.
You can use this along with "guestfs_lvs" and
"guestfs_lvuuid" calls to associate logical volumes and volume
groups.
See also "guestfs_vgpvuuids".
This function returns a NULL-terminated array of strings (like
environ(3)), or NULL if there was an error.
The caller must free the
strings and the array after use.
(Added in 1.0.87)
char *
guestfs_vgmeta (guestfs_h *g,
const char *vgname,
size_t *size_r);
"vgname" is an LVM volume group. This command examines the volume
group and returns its metadata.
Note that the metadata is an internal structure used by LVM, subject to change
at any time, and is provided for information only.
This function returns a buffer, or NULL on error. The size of the returned
buffer is written to *size_r.
The caller must free the returned buffer
after use.
(Added in 1.17.20)
guestfs_vgpvuuids¶
char **
guestfs_vgpvuuids (guestfs_h *g,
const char *vgname);
Given a VG called "vgname", this returns the UUIDs of all the physical
volumes that this volume group resides on.
You can use this along with "guestfs_pvs" and
"guestfs_pvuuid" calls to associate physical volumes and volume
groups.
See also "guestfs_vglvuuids".
This function returns a NULL-terminated array of strings (like
environ(3)), or NULL if there was an error.
The caller must free the
strings and the array after use.
(Added in 1.0.87)
guestfs_vgremove¶
int
guestfs_vgremove (guestfs_h *g,
const char *vgname);
Remove an LVM volume group "vgname", (for example "VG").
This also forcibly removes all logical volumes in the volume group (if any).
This function returns 0 on success or -1 on error.
(Added in 1.0.13)
guestfs_vgrename¶
int
guestfs_vgrename (guestfs_h *g,
const char *volgroup,
const char *newvolgroup);
Rename a volume group "volgroup" with the new name
"newvolgroup".
This function returns 0 on success or -1 on error.
(Added in 1.0.83)
guestfs_vgs¶
char **
guestfs_vgs (guestfs_h *g);
List all the volumes groups detected. This is the equivalent of the
vgs(8) command.
This returns a list of just the volume group names that were detected (eg.
"VolGroup00").
See also "guestfs_vgs_full".
This function returns a NULL-terminated array of strings (like
environ(3)), or NULL if there was an error.
The caller must free the
strings and the array after use.
(Added in 0.4)
guestfs_vgs_full¶
struct guestfs_lvm_vg_list *
guestfs_vgs_full (guestfs_h *g);
List all the volumes groups detected. This is the equivalent of the
vgs(8) command. The "full" version includes all fields.
This function returns a "struct guestfs_lvm_vg_list *", or NULL if
there was an error.
The caller must call
"guestfs_free_lvm_vg_list" after use.
(Added in 0.4)
guestfs_vgscan¶
int
guestfs_vgscan (guestfs_h *g);
This rescans all block devices and rebuilds the list of LVM physical volumes,
volume groups and logical volumes.
This function returns 0 on success or -1 on error.
(Added in 1.3.2)
guestfs_vguuid¶
char *
guestfs_vguuid (guestfs_h *g,
const char *vgname);
This command returns the UUID of the LVM VG named "vgname".
This function returns a string, or NULL on error.
The caller must free the
returned string after use.
(Added in 1.0.87)
guestfs_wait_ready¶
int
guestfs_wait_ready (guestfs_h *g);
This function is deprecated. In new code, use the
"guestfs_launch" call instead.
Deprecated functions will not be removed from the API, but the fact that they
are deprecated indicates that there are problems with correct use of these
functions.
This function is a no op.
In versions of the API < 1.0.71 you had to call this function just after
calling "guestfs_launch" to wait for the launch to complete. However
this is no longer necessary because "guestfs_launch" now does the
waiting.
If you see any calls to this function in code then you can just remove them,
unless you want to retain compatibility with older versions of the API.
This function returns 0 on success or -1 on error.
(Added in 0.3)
guestfs_wc_c¶
int
guestfs_wc_c (guestfs_h *g,
const char *path);
This command counts the characters in a file, using the "wc -c"
external command.
On error this function returns -1.
(Added in 1.0.54)
guestfs_wc_l¶
int
guestfs_wc_l (guestfs_h *g,
const char *path);
This command counts the lines in a file, using the "wc -l" external
command.
On error this function returns -1.
(Added in 1.0.54)
guestfs_wc_w¶
int
guestfs_wc_w (guestfs_h *g,
const char *path);
This command counts the words in a file, using the "wc -w" external
command.
On error this function returns -1.
(Added in 1.0.54)
guestfs_wipefs¶
int
guestfs_wipefs (guestfs_h *g,
const char *device);
This command erases filesystem or RAID signatures from the specified
"device" to make the filesystem invisible to libblkid.
This does not erase the filesystem itself nor any other data from the
"device".
Compare with "guestfs_zero" which zeroes the first few blocks of a
device.
This function returns 0 on success or -1 on error.
(Added in 1.17.6)
guestfs_write¶
int
guestfs_write (guestfs_h *g,
const char *path,
const char *content,
size_t content_size);
This call creates a file called "path". The content of the file is the
string "content" (which can contain any 8 bit data).
See also "guestfs_write_append".
This function returns 0 on success or -1 on error.
Because of the message protocol, there is a transfer limit of somewhere between
2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
(Added in 1.3.14)
guestfs_write_append¶
int
guestfs_write_append (guestfs_h *g,
const char *path,
const char *content,
size_t content_size);
This call appends "content" to the end of file "path". If
"path" does not exist, then a new file is created.
See also "guestfs_write".
This function returns 0 on success or -1 on error.
Because of the message protocol, there is a transfer limit of somewhere between
2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
(Added in 1.11.18)
guestfs_write_file¶
int
guestfs_write_file (guestfs_h *g,
const char *path,
const char *content,
int size);
This function is deprecated. In new code, use the
"guestfs_write" call instead.
Deprecated functions will not be removed from the API, but the fact that they
are deprecated indicates that there are problems with correct use of these
functions.
This call creates a file called "path". The contents of the file is
the string "content" (which can contain any 8 bit data), with length
"size".
As a special case, if "size" is 0 then the length is calculated using
"strlen" (so in this case the content cannot contain embedded ASCII
NULs).
NB. Owing to a bug, writing content containing ASCII NUL characters does
not work, even if the length is specified.
This function returns 0 on success or -1 on error.
Because of the message protocol, there is a transfer limit of somewhere between
2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
(Added in 0.8)
guestfs_zegrep¶
char **
guestfs_zegrep (guestfs_h *g,
const char *regex,
const char *path);
This calls the external "zegrep" program and returns the matching
lines.
This function returns a NULL-terminated array of strings (like
environ(3)), or NULL if there was an error.
The caller must free the
strings and the array after use.
Because of the message protocol, there is a transfer limit of somewhere between
2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
(Added in 1.0.66)
guestfs_zegrepi¶
char **
guestfs_zegrepi (guestfs_h *g,
const char *regex,
const char *path);
This calls the external "zegrep -i" program and returns the matching
lines.
This function returns a NULL-terminated array of strings (like
environ(3)), or NULL if there was an error.
The caller must free the
strings and the array after use.
Because of the message protocol, there is a transfer limit of somewhere between
2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
(Added in 1.0.66)
guestfs_zero¶
int
guestfs_zero (guestfs_h *g,
const char *device);
This command writes zeroes over the first few blocks of "device".
How many blocks are zeroed isn't specified (but it's
not enough to
securely wipe the device). It should be sufficient to remove any partition
tables, filesystem superblocks and so on.
If blocks are already zero, then this command avoids writing zeroes. This
prevents the underlying device from becoming non-sparse or growing
unnecessarily.
See also: "guestfs_zero_device", "guestfs_scrub_device",
"guestfs_is_zero_device"
This function returns 0 on success or -1 on error.
This long-running command can generate progress notification messages so that
the caller can display a progress bar or indicator. To receive these messages,
the caller must register a progress event callback. See
"GUESTFS_EVENT_PROGRESS" in
guestfs(3).
(Added in 1.0.16)
guestfs_zero_device¶
int
guestfs_zero_device (guestfs_h *g,
const char *device);
This command writes zeroes over the entire "device". Compare with
"guestfs_zero" which just zeroes the first few blocks of a device.
If blocks are already zero, then this command avoids writing zeroes. This
prevents the underlying device from becoming non-sparse or growing
unnecessarily.
This function returns 0 on success or -1 on error.
This long-running command can generate progress notification messages so that
the caller can display a progress bar or indicator. To receive these messages,
the caller must register a progress event callback. See
"GUESTFS_EVENT_PROGRESS" in
guestfs(3).
(Added in 1.3.1)
guestfs_zero_free_space¶
int
guestfs_zero_free_space (guestfs_h *g,
const char *directory);
Zero the free space in the filesystem mounted on "directory". The
filesystem must be mounted read-write.
The filesystem contents are not affected, but any free space in the filesystem
is freed.
In future (but not currently) these zeroed blocks will be "sparsified"
- that is, given back to the host.
This function returns 0 on success or -1 on error.
This long-running command can generate progress notification messages so that
the caller can display a progress bar or indicator. To receive these messages,
the caller must register a progress event callback. See
"GUESTFS_EVENT_PROGRESS" in
guestfs(3).
(Added in 1.17.18)
guestfs_zerofree¶
int
guestfs_zerofree (guestfs_h *g,
const char *device);
This runs the
zerofree program on "device". This program claims
to zero unused inodes and disk blocks on an ext2/3 filesystem, thus making it
possible to compress the filesystem more effectively.
You should
not run this program if the filesystem is mounted.
It is possible that using this program can damage the filesystem or data on the
filesystem.
This function returns 0 on success or -1 on error.
(Added in 1.0.26)
guestfs_zfgrep¶
char **
guestfs_zfgrep (guestfs_h *g,
const char *pattern,
const char *path);
This calls the external "zfgrep" program and returns the matching
lines.
This function returns a NULL-terminated array of strings (like
environ(3)), or NULL if there was an error.
The caller must free the
strings and the array after use.
Because of the message protocol, there is a transfer limit of somewhere between
2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
(Added in 1.0.66)
guestfs_zfgrepi¶
char **
guestfs_zfgrepi (guestfs_h *g,
const char *pattern,
const char *path);
This calls the external "zfgrep -i" program and returns the matching
lines.
This function returns a NULL-terminated array of strings (like
environ(3)), or NULL if there was an error.
The caller must free the
strings and the array after use.
Because of the message protocol, there is a transfer limit of somewhere between
2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
(Added in 1.0.66)
guestfs_zfile¶
char *
guestfs_zfile (guestfs_h *g,
const char *meth,
const char *path);
This function is deprecated. In new code, use the
"guestfs_file" call instead.
Deprecated functions will not be removed from the API, but the fact that they
are deprecated indicates that there are problems with correct use of these
functions.
This command runs "file" after first decompressing "path"
using "method".
"method" must be one of "gzip", "compress" or
"bzip2".
Since 1.0.63, use "guestfs_file" instead which can now process
compressed files.
This function returns a string, or NULL on error.
The caller must free the
returned string after use.
(Added in 1.0.59)
guestfs_zgrep¶
char **
guestfs_zgrep (guestfs_h *g,
const char *regex,
const char *path);
This calls the external "zgrep" program and returns the matching
lines.
This function returns a NULL-terminated array of strings (like
environ(3)), or NULL if there was an error.
The caller must free the
strings and the array after use.
Because of the message protocol, there is a transfer limit of somewhere between
2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
(Added in 1.0.66)
guestfs_zgrepi¶
char **
guestfs_zgrepi (guestfs_h *g,
const char *regex,
const char *path);
This calls the external "zgrep -i" program and returns the matching
lines.
This function returns a NULL-terminated array of strings (like
environ(3)), or NULL if there was an error.
The caller must free the
strings and the array after use.
Because of the message protocol, there is a transfer limit of somewhere between
2MB and 4MB. See "PROTOCOL LIMITS" in
guestfs(3).
(Added in 1.0.66)
STRUCTURES¶
guestfs_int_bool¶
struct guestfs_int_bool {
int32_t i;
int32_t b;
};
struct guestfs_int_bool_list {
uint32_t len; /* Number of elements in list. */
struct guestfs_int_bool *val; /* Elements. */
};
void guestfs_free_int_bool (struct guestfs_free_int_bool *);
void guestfs_free_int_bool_list (struct guestfs_free_int_bool_list *);
guestfs_lvm_pv¶
struct guestfs_lvm_pv {
char *pv_name;
/* The next field is NOT nul-terminated, be careful when printing it: */
char pv_uuid[32];
char *pv_fmt;
uint64_t pv_size;
uint64_t dev_size;
uint64_t pv_free;
uint64_t pv_used;
char *pv_attr;
int64_t pv_pe_count;
int64_t pv_pe_alloc_count;
char *pv_tags;
uint64_t pe_start;
int64_t pv_mda_count;
uint64_t pv_mda_free;
};
struct guestfs_lvm_pv_list {
uint32_t len; /* Number of elements in list. */
struct guestfs_lvm_pv *val; /* Elements. */
};
void guestfs_free_lvm_pv (struct guestfs_free_lvm_pv *);
void guestfs_free_lvm_pv_list (struct guestfs_free_lvm_pv_list *);
guestfs_lvm_vg¶
struct guestfs_lvm_vg {
char *vg_name;
/* The next field is NOT nul-terminated, be careful when printing it: */
char vg_uuid[32];
char *vg_fmt;
char *vg_attr;
uint64_t vg_size;
uint64_t vg_free;
char *vg_sysid;
uint64_t vg_extent_size;
int64_t vg_extent_count;
int64_t vg_free_count;
int64_t max_lv;
int64_t max_pv;
int64_t pv_count;
int64_t lv_count;
int64_t snap_count;
int64_t vg_seqno;
char *vg_tags;
int64_t vg_mda_count;
uint64_t vg_mda_free;
};
struct guestfs_lvm_vg_list {
uint32_t len; /* Number of elements in list. */
struct guestfs_lvm_vg *val; /* Elements. */
};
void guestfs_free_lvm_vg (struct guestfs_free_lvm_vg *);
void guestfs_free_lvm_vg_list (struct guestfs_free_lvm_vg_list *);
guestfs_lvm_lv¶
struct guestfs_lvm_lv {
char *lv_name;
/* The next field is NOT nul-terminated, be careful when printing it: */
char lv_uuid[32];
char *lv_attr;
int64_t lv_major;
int64_t lv_minor;
int64_t lv_kernel_major;
int64_t lv_kernel_minor;
uint64_t lv_size;
int64_t seg_count;
char *origin;
/* The next field is [0..100] or -1 meaning 'not present': */
float snap_percent;
/* The next field is [0..100] or -1 meaning 'not present': */
float copy_percent;
char *move_pv;
char *lv_tags;
char *mirror_log;
char *modules;
};
struct guestfs_lvm_lv_list {
uint32_t len; /* Number of elements in list. */
struct guestfs_lvm_lv *val; /* Elements. */
};
void guestfs_free_lvm_lv (struct guestfs_free_lvm_lv *);
void guestfs_free_lvm_lv_list (struct guestfs_free_lvm_lv_list *);
guestfs_stat¶
struct guestfs_stat {
int64_t dev;
int64_t ino;
int64_t mode;
int64_t nlink;
int64_t uid;
int64_t gid;
int64_t rdev;
int64_t size;
int64_t blksize;
int64_t blocks;
int64_t atime;
int64_t mtime;
int64_t ctime;
};
struct guestfs_stat_list {
uint32_t len; /* Number of elements in list. */
struct guestfs_stat *val; /* Elements. */
};
void guestfs_free_stat (struct guestfs_free_stat *);
void guestfs_free_stat_list (struct guestfs_free_stat_list *);
guestfs_statvfs¶
struct guestfs_statvfs {
int64_t bsize;
int64_t frsize;
int64_t blocks;
int64_t bfree;
int64_t bavail;
int64_t files;
int64_t ffree;
int64_t favail;
int64_t fsid;
int64_t flag;
int64_t namemax;
};
struct guestfs_statvfs_list {
uint32_t len; /* Number of elements in list. */
struct guestfs_statvfs *val; /* Elements. */
};
void guestfs_free_statvfs (struct guestfs_free_statvfs *);
void guestfs_free_statvfs_list (struct guestfs_free_statvfs_list *);
guestfs_dirent¶
struct guestfs_dirent {
int64_t ino;
char ftyp;
char *name;
};
struct guestfs_dirent_list {
uint32_t len; /* Number of elements in list. */
struct guestfs_dirent *val; /* Elements. */
};
void guestfs_free_dirent (struct guestfs_free_dirent *);
void guestfs_free_dirent_list (struct guestfs_free_dirent_list *);
guestfs_version¶
struct guestfs_version {
int64_t major;
int64_t minor;
int64_t release;
char *extra;
};
struct guestfs_version_list {
uint32_t len; /* Number of elements in list. */
struct guestfs_version *val; /* Elements. */
};
void guestfs_free_version (struct guestfs_free_version *);
void guestfs_free_version_list (struct guestfs_free_version_list *);
guestfs_xattr¶
struct guestfs_xattr {
char *attrname;
/* The next two fields describe a byte array. */
uint32_t attrval_len;
char *attrval;
};
struct guestfs_xattr_list {
uint32_t len; /* Number of elements in list. */
struct guestfs_xattr *val; /* Elements. */
};
void guestfs_free_xattr (struct guestfs_free_xattr *);
void guestfs_free_xattr_list (struct guestfs_free_xattr_list *);
guestfs_inotify_event¶
struct guestfs_inotify_event {
int64_t in_wd;
uint32_t in_mask;
uint32_t in_cookie;
char *in_name;
};
struct guestfs_inotify_event_list {
uint32_t len; /* Number of elements in list. */
struct guestfs_inotify_event *val; /* Elements. */
};
void guestfs_free_inotify_event (struct guestfs_free_inotify_event *);
void guestfs_free_inotify_event_list (struct guestfs_free_inotify_event_list *);
guestfs_partition¶
struct guestfs_partition {
int32_t part_num;
uint64_t part_start;
uint64_t part_end;
uint64_t part_size;
};
struct guestfs_partition_list {
uint32_t len; /* Number of elements in list. */
struct guestfs_partition *val; /* Elements. */
};
void guestfs_free_partition (struct guestfs_free_partition *);
void guestfs_free_partition_list (struct guestfs_free_partition_list *);
guestfs_application¶
struct guestfs_application {
char *app_name;
char *app_display_name;
int32_t app_epoch;
char *app_version;
char *app_release;
char *app_install_path;
char *app_trans_path;
char *app_publisher;
char *app_url;
char *app_source_package;
char *app_summary;
char *app_description;
};
struct guestfs_application_list {
uint32_t len; /* Number of elements in list. */
struct guestfs_application *val; /* Elements. */
};
void guestfs_free_application (struct guestfs_free_application *);
void guestfs_free_application_list (struct guestfs_free_application_list *);
guestfs_isoinfo¶
struct guestfs_isoinfo {
char *iso_system_id;
char *iso_volume_id;
uint32_t iso_volume_space_size;
uint32_t iso_volume_set_size;
uint32_t iso_volume_sequence_number;
uint32_t iso_logical_block_size;
char *iso_volume_set_id;
char *iso_publisher_id;
char *iso_data_preparer_id;
char *iso_application_id;
char *iso_copyright_file_id;
char *iso_abstract_file_id;
char *iso_bibliographic_file_id;
int64_t iso_volume_creation_t;
int64_t iso_volume_modification_t;
int64_t iso_volume_expiration_t;
int64_t iso_volume_effective_t;
};
struct guestfs_isoinfo_list {
uint32_t len; /* Number of elements in list. */
struct guestfs_isoinfo *val; /* Elements. */
};
void guestfs_free_isoinfo (struct guestfs_free_isoinfo *);
void guestfs_free_isoinfo_list (struct guestfs_free_isoinfo_list *);
guestfs_mdstat¶
struct guestfs_mdstat {
char *mdstat_device;
int32_t mdstat_index;
char *mdstat_flags;
};
struct guestfs_mdstat_list {
uint32_t len; /* Number of elements in list. */
struct guestfs_mdstat *val; /* Elements. */
};
void guestfs_free_mdstat (struct guestfs_free_mdstat *);
void guestfs_free_mdstat_list (struct guestfs_free_mdstat_list *);
guestfs_btrfssubvolume¶
struct guestfs_btrfssubvolume {
uint64_t btrfssubvolume_id;
uint64_t btrfssubvolume_top_level_id;
char *btrfssubvolume_path;
};
struct guestfs_btrfssubvolume_list {
uint32_t len; /* Number of elements in list. */
struct guestfs_btrfssubvolume *val; /* Elements. */
};
void guestfs_free_btrfssubvolume (struct guestfs_free_btrfssubvolume *);
void guestfs_free_btrfssubvolume_list (struct guestfs_free_btrfssubvolume_list *);
AVAILABILITY¶
GROUPS OF FUNCTIONALITY IN THE APPLIANCE¶
Using "guestfs_available" you can test availability of the following
groups of functions. This test queries the appliance to see if the appliance
you are currently using supports the functionality.
- augeas
- The following functions: "guestfs_aug_clear"
"guestfs_aug_close" "guestfs_aug_defnode"
"guestfs_aug_defvar" "guestfs_aug_get"
"guestfs_aug_init" "guestfs_aug_insert"
"guestfs_aug_load" "guestfs_aug_ls"
"guestfs_aug_match" "guestfs_aug_mv"
"guestfs_aug_rm" "guestfs_aug_save"
"guestfs_aug_set"
- btrfs
- The following functions:
"guestfs_btrfs_device_add"
"guestfs_btrfs_device_delete"
"guestfs_btrfs_filesystem_balance"
"guestfs_btrfs_filesystem_resize"
"guestfs_btrfs_filesystem_sync" "guestfs_btrfs_fsck"
"guestfs_btrfs_set_seeding"
"guestfs_btrfs_subvolume_create"
"guestfs_btrfs_subvolume_delete"
"guestfs_btrfs_subvolume_list"
"guestfs_btrfs_subvolume_set_default"
"guestfs_btrfs_subvolume_snapshot"
"guestfs_mkfs_btrfs"
- grub
- The following functions:
"guestfs_grub_install"
- inotify
- The following functions:
"guestfs_inotify_add_watch" "guestfs_inotify_close"
"guestfs_inotify_files" "guestfs_inotify_init"
"guestfs_inotify_read" "guestfs_inotify_rm_watch"
- linuxfsuuid
- The following functions: "guestfs_mke2fs_JU"
"guestfs_mke2journal_U" "guestfs_mkswap_U"
"guestfs_swapoff_uuid" "guestfs_swapon_uuid"
- linuxmodules
- The following functions: "guestfs_modprobe"
- linuxxattrs
- The following functions: "guestfs_getxattr"
"guestfs_getxattrs" "guestfs_lgetxattr"
"guestfs_lgetxattrs" "guestfs_lremovexattr"
"guestfs_lsetxattr" "guestfs_lxattrlist"
"guestfs_removexattr" "guestfs_setxattr"
- luks
- The following functions: "guestfs_luks_add_key"
"guestfs_luks_close" "guestfs_luks_format"
"guestfs_luks_format_cipher" "guestfs_luks_kill_slot"
"guestfs_luks_open" "guestfs_luks_open_ro"
- lvm2
- The following functions: "guestfs_is_lv"
"guestfs_lvcreate" "guestfs_lvcreate_free"
"guestfs_lvm_remove_all" "guestfs_lvm_set_filter"
"guestfs_lvremove" "guestfs_lvresize"
"guestfs_lvresize_free" "guestfs_lvs"
"guestfs_lvs_full" "guestfs_pvcreate"
"guestfs_pvremove" "guestfs_pvresize"
"guestfs_pvresize_size" "guestfs_pvs"
"guestfs_pvs_full" "guestfs_vg_activate"
"guestfs_vg_activate_all" "guestfs_vgcreate"
"guestfs_vgmeta" "guestfs_vgremove"
"guestfs_vgs" "guestfs_vgs_full"
- mdadm
- The following functions: "guestfs_md_create"
"guestfs_md_detail" "guestfs_md_stat"
"guestfs_md_stop"
- mknod
- The following functions: "guestfs_mkfifo"
"guestfs_mknod" "guestfs_mknod_b"
"guestfs_mknod_c"
- ntfs3g
- The following functions: "guestfs_ntfs_3g_probe"
"guestfs_ntfsclone_in" "guestfs_ntfsclone_out"
"guestfs_ntfsfix"
- ntfsprogs
- The following functions: "guestfs_ntfsresize"
"guestfs_ntfsresize_opts"
"guestfs_ntfsresize_size"
- realpath
- The following functions: "guestfs_realpath"
- scrub
- The following functions: "guestfs_scrub_device"
"guestfs_scrub_file" "guestfs_scrub_freespace"
- selinux
- The following functions: "guestfs_getcon"
"guestfs_setcon"
- wipefs
- The following functions: "guestfs_wipefs"
- xz
- The following functions: "guestfs_txz_in"
"guestfs_txz_out"
- zerofree
- The following functions: "guestfs_zerofree"
GUESTFISH supported COMMAND¶
In
guestfish(3) there is a handy interactive command
"supported" which prints out the available groups and whether they
are supported by this build of libguestfs. Note however that you have to do
"run" first.
SINGLE CALLS AT COMPILE TIME¶
Since version 1.5.8, "<guestfs.h>" defines symbols for each C
API function, such as:
#define LIBGUESTFS_HAVE_DD 1
if "guestfs_dd" is available.
Before version 1.5.8, if you needed to test whether a single libguestfs function
is available at compile time, we recommended using build tools such as
autoconf or cmake. For example in autotools you could use:
AC_CHECK_LIB([guestfs],[guestfs_create])
AC_CHECK_FUNCS([guestfs_dd])
which would result in "HAVE_GUESTFS_DD" being either defined or not
defined in your program.
SINGLE CALLS AT RUN TIME¶
Testing at compile time doesn't guarantee that a function really exists in the
library. The reason is that you might be dynamically linked against a previous
libguestfs.so (dynamic library) which doesn't have the call. This
situation unfortunately results in a segmentation fault, which is a
shortcoming of the C dynamic linking system itself.
You can use
dlopen(3) to test if a function is available at run time, as
in this example program (note that you still need the compile time check as
well):
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <dlfcn.h>
#include <guestfs.h>
main ()
{
#ifdef LIBGUESTFS_HAVE_DD
void *dl;
int has_function;
/* Test if the function guestfs_dd is really available. */
dl = dlopen (NULL, RTLD_LAZY);
if (!dl) {
fprintf (stderr, "dlopen: %s\n", dlerror ());
exit (EXIT_FAILURE);
}
has_function = dlsym (dl, "guestfs_dd") != NULL;
dlclose (dl);
if (!has_function)
printf ("this libguestfs.so does NOT have guestfs_dd function\n");
else {
printf ("this libguestfs.so has guestfs_dd function\n");
/* Now it's safe to call
guestfs_dd (g, "foo", "bar");
*/
}
#else
printf ("guestfs_dd function was not found at compile time\n");
#endif
}
You may think the above is an awful lot of hassle, and it is. There are other
ways outside of the C linking system to ensure that this kind of
incompatibility never arises, such as using package versioning:
Requires: libguestfs >= 1.0.80
CALLS WITH OPTIONAL ARGUMENTS¶
A recent feature of the API is the introduction of calls which take optional
arguments. In C these are declared 3 ways. The main way is as a call which
takes variable arguments (ie. "..."), as in this example:
int guestfs_add_drive_opts (guestfs_h *g, const char *filename, ...);
Call this with a list of optional arguments, terminated by "-1". So to
call with no optional arguments specified:
guestfs_add_drive_opts (g, filename, -1);
With a single optional argument:
guestfs_add_drive_opts (g, filename,
GUESTFS_ADD_DRIVE_OPTS_FORMAT, "qcow2",
-1);
With two:
guestfs_add_drive_opts (g, filename,
GUESTFS_ADD_DRIVE_OPTS_FORMAT, "qcow2",
GUESTFS_ADD_DRIVE_OPTS_READONLY, 1,
-1);
and so forth. Don't forget the terminating "-1" otherwise Bad Things
will happen!
USING va_list FOR OPTIONAL ARGUMENTS¶
The second variant has the same name with the suffix "_va", which
works the same way but takes a "va_list". See the C manual for
details. For the example function, this is declared:
int guestfs_add_drive_opts_va (guestfs_h *g, const char *filename,
va_list args);
CONSTRUCTING OPTIONAL ARGUMENTS¶
The third variant is useful where you need to construct these calls. You pass in
a structure where you fill in the optional fields. The structure has a bitmask
as the first element which you must set to indicate which fields you have
filled in. For our example function the structure and call are declared:
struct guestfs_add_drive_opts_argv {
uint64_t bitmask;
int readonly;
const char *format;
/* ... */
};
int guestfs_add_drive_opts_argv (guestfs_h *g, const char *filename,
const struct guestfs_add_drive_opts_argv *optargs);
You could call it like this:
struct guestfs_add_drive_opts_argv optargs = {
.bitmask = GUESTFS_ADD_DRIVE_OPTS_READONLY_BITMASK |
GUESTFS_ADD_DRIVE_OPTS_FORMAT_BITMASK,
.readonly = 1,
.format = "qcow2"
};
guestfs_add_drive_opts_argv (g, filename, &optargs);
Notes:
- •
- The "_BITMASK" suffix on each option name when
specifying the bitmask.
- •
- You do not need to fill in all fields of the
structure.
- •
- There must be a one-to-one correspondence between fields of
the structure that are filled in, and bits set in the bitmask.
OPTIONAL ARGUMENTS IN OTHER LANGUAGES¶
In other languages, optional arguments are expressed in the way that is natural
for that language. We refer you to the language-specific documentation for
more details on that.
For guestfish, see "OPTIONAL ARGUMENTS" in
guestfish(1).
SETTING CALLBACKS TO HANDLE EVENTS¶
Note: This section documents the generic event mechanism introduced in
libguestfs 1.10, which you should use in new code if possible. The old
functions "guestfs_set_log_message_callback",
"guestfs_set_subprocess_quit_callback",
"guestfs_set_launch_done_callback",
"guestfs_set_close_callback" and
"guestfs_set_progress_callback" are no longer documented in this
manual page. Because of the ABI guarantee, the old functions continue to work.
Handles generate events when certain things happen, such as log messages being
generated, progress messages during long-running operations, or the handle
being closed. The API calls described below let you register a callback to be
called when events happen. You can register multiple callbacks (for the same,
different or overlapping sets of events), and individually remove callbacks.
If callbacks are not removed, then they remain in force until the handle is
closed.
In the current implementation, events are only generated synchronously: that
means that events (and hence callbacks) can only happen while you are in the
middle of making another libguestfs call. The callback is called in the same
thread.
Events may contain a payload, usually nothing (void), an array of 64 bit
unsigned integers, or a message buffer. Payloads are discussed later on.
CLASSES OF EVENTS
- GUESTFS_EVENT_CLOSE (payload type: void)
- The callback function will be called while the handle is
being closed (synchronously from "guestfs_close").
Note that libguestfs installs an atexit(3) handler to try to clean up
handles that are open when the program exits. This means that this
callback might be called indirectly from exit(3), which can cause
unexpected problems in higher-level languages (eg. if your HLL interpreter
has already been cleaned up by the time this is called, and if your
callback then jumps into some HLL function).
If no callback is registered: the handle is closed without any callback
being invoked.
- GUESTFS_EVENT_SUBPROCESS_QUIT (payload type: void)
- The callback function will be called when the child process
quits, either asynchronously or if killed by
"guestfs_kill_subprocess". (This corresponds to a transition
from any state to the CONFIG state).
If no callback is registered: the event is ignored.
- GUESTFS_EVENT_LAUNCH_DONE (payload type: void)
- The callback function will be called when the child process
becomes ready first time after it has been launched. (This corresponds to
a transition from LAUNCHING to the READY state).
If no callback is registered: the event is ignored.
- GUESTFS_EVENT_PROGRESS (payload type: array of 4 x
uint64_t)
- Some long-running operations can generate progress
messages. If this callback is registered, then it will be called each time
a progress message is generated (usually two seconds after the operation
started, and three times per second thereafter until it completes,
although the frequency may change in future versions).
The callback receives in the payload four unsigned 64 bit numbers which are
(in order): "proc_nr", "serial", "position",
"total".
The units of "total" are not defined, although for some operations
"total" may relate in some way to the amount of data to be
transferred (eg. in bytes or megabytes), and "position" may be
the portion which has been transferred.
The only defined and stable parts of the API are:
- •
- The callback can display to the user some type of progress
bar or indicator which shows the ratio of
"position":"total".
- •
- 0 <= "position" <= "total"
- •
- If any progress notification is sent during a call, then a
final progress notification is always sent when "position" =
"total" ( unless the call fails with an error).
This is to simplify caller code, so callers can easily set the progress
indicator to "100%" at the end of the operation, without
requiring special code to detect this case.
- •
- For some calls we are unable to estimate the progress of
the call, but we can still generate progress messages to indicate
activity. This is known as "pulse mode", and is directly
supported by certain progress bar implementations (eg. GtkProgressBar).
For these calls, zero or more progress messages are generated with
"position = 0" and "total = 1", followed by a final
message with "position = total = 1".
As noted above, if the call fails with an error then the final message may
not be generated.
The callback also receives the procedure number ("proc_nr") and serial
number ("serial") of the call. These are only useful for debugging
protocol issues, and the callback can normally ignore them. The callback may
want to print these numbers in error messages or debugging messages.
If no callback is registered: progress messages are discarded.
- GUESTFS_EVENT_APPLIANCE (payload type: message buffer)
- The callback function is called whenever a log message is
generated by qemu, the appliance kernel, guestfsd (daemon), or utility
programs.
If the verbose flag ("guestfs_set_verbose") is set before launch
("guestfs_launch") then additional debug messages are generated.
If no callback is registered: the messages are discarded unless the verbose
flag is set in which case they are sent to stderr. You can override the
printing of verbose messages to stderr by setting up a callback.
- GUESTFS_EVENT_LIBRARY (payload type: message buffer)
- The callback function is called whenever a log message is
generated by the library part of libguestfs.
If the verbose flag ("guestfs_set_verbose") is set then additional
debug messages are generated.
If no callback is registered: the messages are discarded unless the verbose
flag is set in which case they are sent to stderr. You can override the
printing of verbose messages to stderr by setting up a callback.
- GUESTFS_EVENT_TRACE (payload type: message buffer)
- The callback function is called whenever a trace message is
generated. This only applies if the trace flag
("guestfs_set_trace") is set.
If no callback is registered: the messages are sent to stderr. You can
override the printing of trace messages to stderr by setting up a
callback.
- GUESTFS_EVENT_ENTER (payload type: function name)
- The callback function is called whenever a libguestfs
function is entered.
The payload is a string which contains the name of the function that we are
entering (not including "guestfs_" prefix).
Note that libguestfs functions can call themselves, so you may see many
events from a single call. A few libguestfs functions do not generate this
event.
If no callback is registered: the event is ignored.
guestfs_set_event_callback
int guestfs_set_event_callback (guestfs_h *g,
guestfs_event_callback cb,
uint64_t event_bitmask,
int flags,
void *opaque);
This function registers a callback ("cb") for all event classes in the
"event_bitmask".
For example, to register for all log message events, you could call this
function with the bitmask
"GUESTFS_EVENT_APPLIANCE|GUESTFS_EVENT_LIBRARY". To register a
single callback for all possible classes of events, use
"GUESTFS_EVENT_ALL".
"flags" should always be passed as 0.
"opaque" is an opaque pointer which is passed to the callback. You can
use it for any purpose.
The return value is the event handle (an integer) which you can use to delete
the callback (see below).
If there is an error, this function returns "-1", and sets the error
in the handle in the usual way (see "guestfs_last_error" etc.)
Callbacks remain in effect until they are deleted, or until the handle is
closed.
In the case where multiple callbacks are registered for a particular event
class, all of the callbacks are called. The order in which multiple callbacks
are called is not defined.
guestfs_delete_event_callback
void guestfs_delete_event_callback (guestfs_h *g, int event_handle);
Delete a callback that was previously registered. "event_handle"
should be the integer that was returned by a previous call to
"guestfs_set_event_callback" on the same handle.
guestfs_event_callback
typedef void (*guestfs_event_callback) (
guestfs_h *g,
void *opaque,
uint64_t event,
int event_handle,
int flags,
const char *buf, size_t buf_len,
const uint64_t *array, size_t array_len);
This is the type of the event callback function that you have to provide.
The basic parameters are: the handle ("g"), the opaque user pointer
("opaque"), the event class (eg.
"GUESTFS_EVENT_PROGRESS"), the event handle, and "flags"
which in the current API you should ignore.
The remaining parameters contain the event payload (if any). Each event may
contain a payload, which usually relates to the event class, but for future
proofing your code should be written to handle any payload for any event
class.
"buf" and "buf_len" contain a message buffer (if
"buf_len == 0", then there is no message buffer). Note that this
message buffer can contain arbitrary 8 bit data, including NUL bytes.
"array" and "array_len" is an array of 64 bit unsigned
integers. At the moment this is only used for progress messages.
EXAMPLE: CAPTURING LOG MESSAGES
One motivation for the generic event API was to allow GUI programs to capture
debug and other messages. In libguestfs ≤ 1.8 these were sent
unconditionally to "stderr".
Events associated with log messages are: "GUESTFS_EVENT_LIBRARY",
"GUESTFS_EVENT_APPLIANCE" and "GUESTFS_EVENT_TRACE". (Note
that error messages are not events; you must capture error messages
separately).
Programs have to set up a callback to capture the classes of events of interest:
int eh =
guestfs_set_event_callback
(g, message_callback,
GUESTFS_EVENT_LIBRARY|GUESTFS_EVENT_APPLIANCE|
GUESTFS_EVENT_TRACE,
0, NULL) == -1)
if (eh == -1) {
// handle error in the usual way
}
The callback can then direct messages to the appropriate place. In this example,
messages are directed to syslog:
static void
message_callback (
guestfs_h *g,
void *opaque,
uint64_t event,
int event_handle,
int flags,
const char *buf, size_t buf_len,
const uint64_t *array, size_t array_len)
{
const int priority = LOG_USER|LOG_INFO;
if (buf_len > 0)
syslog (priority, "event 0x%lx: %s", event, buf);
}
CANCELLING LONG TRANSFERS¶
Some operations can be cancelled by the caller while they are in progress.
Currently only operations that involve uploading or downloading data can be
cancelled (technically: operations that have "FileIn" or
"FileOut" parameters in the generator).
guestfs_user_cancel¶
void guestfs_user_cancel (guestfs_h *g);
"guestfs_user_cancel" cancels the current upload or download
operation.
Unlike most other libguestfs calls, this function is signal safe and thread
safe. You can call it from a signal handler or from another thread, without
needing to do any locking.
The transfer that was in progress (if there is one) will stop shortly
afterwards, and will return an error. The errno (see
"guestfs_last_errno") is set to "EINTR", so you can test
for this to find out if the operation was cancelled or failed because of
another error.
No cleanup is performed: for example, if a file was being uploaded then after
cancellation there may be a partially uploaded file. It is the caller's
responsibility to clean up if necessary.
There are two common places that you might call "guestfs_user_cancel".
In an interactive text-based program, you might call it from a
"SIGINT" signal handler so that pressing "^C" cancels the
current operation. (You also need to call "guestfs_set_pgroup" so
that child processes don't receive the "^C" signal).
In a graphical program, when the main thread is displaying a progress bar with a
cancel button, wire up the cancel button to call this function.
PRIVATE DATA AREA¶
You can attach named pieces of private data to the libguestfs handle, fetch them
by name, and walk over them, for the lifetime of the handle. This is called
the private data area and is only available from the C API.
To attach a named piece of data, use the following call:
void guestfs_set_private (guestfs_h *g, const char *key, void *data);
"key" is the name to associate with this data, and "data" is
an arbitrary pointer (which can be "NULL"). Any previous item with
the same key is overwritten.
You can use any "key" you want, but your key should
not start
with an underscore character. Keys beginning with an underscore character are
reserved for internal libguestfs purposes (eg. for implementing language
bindings). It is recommended that you prefix the key with some unique string
to avoid collisions with other users.
To retrieve the pointer, use:
void *guestfs_get_private (guestfs_h *g, const char *key);
This function returns "NULL" if either no data is found associated
with "key", or if the user previously set the "key"'s
"data" pointer to "NULL".
Libguestfs does not try to look at or interpret the "data" pointer in
any way. As far as libguestfs is concerned, it need not be a valid pointer at
all. In particular, libguestfs does
not try to free the data when the
handle is closed. If the data must be freed, then the caller must either free
it before calling "guestfs_close" or must set up a close callback to
do it (see "GUESTFS_EVENT_CLOSE").
To walk over all entries, use these two functions:
void *guestfs_first_private (guestfs_h *g, const char **key_rtn);
void *guestfs_next_private (guestfs_h *g, const char **key_rtn);
"guestfs_first_private" returns the first key, pointer pair
("first" does not have any particular meaning -- keys are not
returned in any defined order). A pointer to the key is returned in *key_rtn
and the corresponding data pointer is returned from the function.
"NULL" is returned if there are no keys stored in the handle.
"guestfs_next_private" returns the next key, pointer pair. The return
value of this function is also "NULL" is there are no further
entries to return.
Notes about walking over entries:
- •
- You must not call "guestfs_set_private" while
walking over the entries.
- •
- The handle maintains an internal iterator which is reset
when you call "guestfs_first_private". This internal iterator is
invalidated when you call "guestfs_set_private".
- •
- If you have set the data pointer associated with a key to
"NULL", ie:
guestfs_set_private (g, key, NULL);
then that "key" is not returned when walking.
- •
- *key_rtn is only valid until the next call to
"guestfs_first_private", "guestfs_next_private" or
"guestfs_set_private".
The following example code shows how to print all keys and data pointers that
are associated with the handle "g":
const char *key;
void *data = guestfs_first_private (g, &key);
while (data != NULL)
{
printf ("key = %s, data = %p\n", key, data);
data = guestfs_next_private (g, &key);
}
More commonly you are only interested in keys that begin with an
application-specific prefix "foo_". Modify the loop like so:
const char *key;
void *data = guestfs_first_private (g, &key);
while (data != NULL)
{
if (strncmp (key, "foo_", strlen ("foo_")) == 0)
printf ("key = %s, data = %p\n", key, data);
data = guestfs_next_private (g, &key);
}
If you need to modify keys while walking, then you have to jump back to the
beginning of the loop. For example, to delete all keys prefixed with
"foo_":
const char *key;
void *data;
again:
data = guestfs_first_private (g, &key);
while (data != NULL)
{
if (strncmp (key, "foo_", strlen ("foo_")) == 0)
{
guestfs_set_private (g, key, NULL);
/* note that 'key' pointer is now invalid, and so is
the internal iterator */
goto again;
}
data = guestfs_next_private (g, &key);
}
Note that the above loop is guaranteed to terminate because the keys are being
deleted, but other manipulations of keys within the loop might not terminate
unless you also maintain an indication of which keys have been visited.
SYSTEMTAP¶
The libguestfs C library can be probed using systemtap or DTrace. This is true
of any library, not just libguestfs. However libguestfs also contains static
markers to help in probing internal operations.
You can list all the static markers by doing:
stap -l 'process("/usr/lib*/libguestfs.so.0")
.provider("guestfs").mark("*")'
Note: These static markers are
not part of the stable API and may
change in future versions.
SYSTEMTAP SCRIPT EXAMPLE¶
This script contains examples of displaying both the static markers and some
ordinary C entry points:
global last;
function display_time () {
now = gettimeofday_us ();
delta = 0;
if (last > 0)
delta = now - last;
last = now;
printf ("%d (+%d):", now, delta);
}
probe begin {
last = 0;
printf ("ready\n");
}
/* Display all calls to static markers. */
probe process("/usr/lib*/libguestfs.so.0")
.provider("guestfs").mark("*") ? {
display_time();
printf ("\t%s %s\n", $$name, $$parms);
}
/* Display all calls to guestfs_mkfs* functions. */
probe process("/usr/lib*/libguestfs.so.0")
.function("guestfs_mkfs*") ? {
display_time();
printf ("\t%s %s\n", probefunc(), $$parms);
}
The script above can be saved to "test.stap" and run using the
stap(1) program. Note that you either have to be root, or you have to
add yourself to several special stap groups. Consult the systemtap
documentation for more information.
# stap /tmp/test.stap
ready
In another terminal, run a guestfish command such as this:
guestfish -N fs
In the first terminal, stap trace output similar to this is shown:
1318248056692655 (+0): launch_start
1318248056692850 (+195): launch_build_appliance_start
1318248056818285 (+125435): launch_build_appliance_end
1318248056838059 (+19774): launch_run_qemu
1318248061071167 (+4233108): launch_end
1318248061280324 (+209157): guestfs_mkfs g=0x1024ab0 fstype=0x46116f device=0x1024e60
ARCHITECTURE¶
Internally, libguestfs is implemented by running an appliance (a special type of
small virtual machine) using
qemu(1). Qemu runs as a child process of
the main program.
___________________
/ \
| main program |
| |
| | child process / appliance
| | __________________________
| | / qemu \
+-------------------+ RPC | +-----------------+ |
| libguestfs <--------------------> guestfsd | |
| | | +-----------------+ |
\___________________/ | | Linux kernel | |
| +--^--------------+ |
\_________|________________/
|
_______v______
/ \
| Device or |
| disk image |
\______________/
The library, linked to the main program, creates the child process and hence the
appliance in the "guestfs_launch" function.
Inside the appliance is a Linux kernel and a complete stack of userspace tools
(such as LVM and ext2 programs) and a small controlling daemon called
"guestfsd". The library talks to "guestfsd" using remote
procedure calls (RPC). There is a mostly one-to-one correspondence between
libguestfs API calls and RPC calls to the daemon. Lastly the disk image(s) are
attached to the qemu process which translates device access by the appliance's
Linux kernel into accesses to the image.
A common misunderstanding is that the appliance "is" the virtual
machine. Although the disk image you are attached to might also be used by
some virtual machine, libguestfs doesn't know or care about this. (But you
will care if both libguestfs's qemu process and your virtual machine are
trying to update the disk image at the same time, since these usually results
in massive disk corruption).
STATE MACHINE¶
libguestfs uses a state machine to model the child process:
|
guestfs_create
|
|
____V_____
/ \
| CONFIG |
\__________/
^ ^ \
| \ \ guestfs_launch
| _\__V______
| / \
| | LAUNCHING |
| \___________/
| /
| guestfs_launch
| /
__|____V
/ \
| READY |
\________/
The normal transitions are (1) CONFIG (when the handle is created, but there is
no child process), (2) LAUNCHING (when the child process is booting up), (3)
READY meaning the appliance is up, actions can be issued to, and carried out
by, the child process.
The guest may be killed by "guestfs_kill_subprocess", or may die
asynchronously at any time (eg. due to some internal error), and that causes
the state to transition back to CONFIG.
Configuration commands for qemu such as "guestfs_add_drive" can only
be issued when in the CONFIG state.
The API offers one call that goes from CONFIG through LAUNCHING to READY.
"guestfs_launch" blocks until the child process is READY to accept
commands (or until some failure or timeout). "guestfs_launch"
internally moves the state from CONFIG to LAUNCHING while it is running.
API actions such as "guestfs_mount" can only be issued when in the
READY state. These API calls block waiting for the command to be carried out.
There are no non-blocking versions, and no way to issue more than one command
per handle at the same time.
Finally, the child process sends asynchronous messages back to the main program,
such as kernel log messages. You can register a callback to receive these
messages.
INTERNALS¶
APPLIANCE BOOT PROCESS¶
This process has evolved and continues to evolve. The description here
corresponds only to the current version of libguestfs and is provided for
information only.
In order to follow the stages involved below, enable libguestfs debugging (set
the environment variable "LIBGUESTFS_DEBUG=1").
- Create the appliance
- "febootstrap-supermin-helper" is invoked to
create the kernel, a small initrd and the appliance.
The appliance is cached in "/var/tmp/.guestfs-<UID>" (or in
another directory if "TMPDIR" is set).
For a complete description of how the appliance is created and cached, read
the febootstrap(8) and febootstrap-supermin-helper(8) man
pages.
- Start qemu and boot the kernel
- qemu is invoked to boot the kernel.
- Run the initrd
- "febootstrap-supermin-helper" builds a small
initrd. The initrd is not the appliance. The purpose of the initrd is to
load enough kernel modules in order that the appliance itself can be
mounted and started.
The initrd is a cpio archive called
"/var/tmp/.guestfs-<UID>/initrd".
When the initrd has started you will see messages showing that kernel
modules are being loaded, similar to this:
febootstrap: ext2 mini initrd starting up
febootstrap: mounting /sys
febootstrap: internal insmod libcrc32c.ko
febootstrap: internal insmod crc32c-intel.ko
- Find and mount the appliance device
- The appliance is a sparse file containing an ext2
filesystem which contains a familiar (although reduced in size) Linux
operating system. It would normally be called
"/var/tmp/.guestfs-<UID>/root".
The regular disks being inspected by libguestfs are the first devices
exposed by qemu (eg. as "/dev/vda").
The last disk added to qemu is the appliance itself (eg.
"/dev/vdb" if there was only one regular disk).
Thus the final job of the initrd is to locate the appliance disk, mount it,
and switch root into the appliance, and run "/init" from the
appliance.
If this works successfully you will see messages such as:
febootstrap: picked /sys/block/vdb/dev as root device
febootstrap: creating /dev/root as block special 252:16
febootstrap: mounting new root on /root
febootstrap: chroot
Starting /init script ...
Note that "Starting /init script ..." indicates that the
appliance's init script is now running.
- Initialize the appliance
- The appliance itself now initializes itself. This involves
starting certain processes like "udev", possibly printing some
debug information, and finally running the daemon
("guestfsd").
- The daemon
- Finally the daemon ("guestfsd") runs inside the
appliance. If it runs you should see:
verbose daemon enabled
The daemon expects to see a named virtio-serial port exposed by qemu and
connected on the other end to the library.
The daemon connects to this port (and hence to the library) and sends a four
byte message "GUESTFS_LAUNCH_FLAG", which initiates the
communication protocol (see below).
COMMUNICATION PROTOCOL¶
Don't rely on using this protocol directly. This section documents how it
currently works, but it may change at any time.
The protocol used to talk between the library and the daemon running inside the
qemu virtual machine is a simple RPC mechanism built on top of XDR (RFC 1014,
RFC 1832, RFC 4506).
The detailed format of structures is in "src/guestfs_protocol.x"
(note: this file is automatically generated).
There are two broad cases, ordinary functions that don't have any
"FileIn" and "FileOut" parameters, which are handled with
very simple request/reply messages. Then there are functions that have any
"FileIn" or "FileOut" parameters, which use the same
request and reply messages, but they may also be followed by files sent using
a chunked encoding.
ORDINARY FUNCTIONS (NO FILEIN/FILEOUT PARAMS)
For ordinary functions, the request message is:
total length (header + arguments,
but not including the length word itself)
struct guestfs_message_header (encoded as XDR)
struct guestfs_<foo>_args (encoded as XDR)
The total length field allows the daemon to allocate a fixed size buffer into
which it slurps the rest of the message. As a result, the total length is
limited to "GUESTFS_MESSAGE_MAX" bytes (currently 4MB), which means
the effective size of any request is limited to somewhere under this size.
Note also that many functions don't take any arguments, in which case the
"guestfs_
foo_args" is completely omitted.
The header contains the procedure number ("guestfs_proc") which is how
the receiver knows what type of args structure to expect, or none at all.
For functions that take optional arguments, the optional arguments are encoded
in the "guestfs_
foo_args" structure in the same way as
ordinary arguments. A bitmask in the header indicates which optional arguments
are meaningful. The bitmask is also checked to see if it contains bits set
which the daemon does not know about (eg. if more optional arguments were
added in a later version of the library), and this causes the call to be
rejected.
The reply message for ordinary functions is:
total length (header + ret,
but not including the length word itself)
struct guestfs_message_header (encoded as XDR)
struct guestfs_<foo>_ret (encoded as XDR)
As above the "guestfs_
foo_ret" structure may be completely
omitted for functions that return no formal return values.
As above the total length of the reply is limited to
"GUESTFS_MESSAGE_MAX".
In the case of an error, a flag is set in the header, and the reply message is
slightly changed:
total length (header + error,
but not including the length word itself)
struct guestfs_message_header (encoded as XDR)
struct guestfs_message_error (encoded as XDR)
The "guestfs_message_error" structure contains the error message as a
string.
FUNCTIONS THAT HAVE FILEIN PARAMETERS
A "FileIn" parameter indicates that we transfer a file
into the
guest. The normal request message is sent (see above). However this is
followed by a sequence of file chunks.
total length (header + arguments,
but not including the length word itself,
and not including the chunks)
struct guestfs_message_header (encoded as XDR)
struct guestfs_<foo>_args (encoded as XDR)
sequence of chunks for FileIn param #0
sequence of chunks for FileIn param #1 etc.
The "sequence of chunks" is:
length of chunk (not including length word itself)
struct guestfs_chunk (encoded as XDR)
length of chunk
struct guestfs_chunk (encoded as XDR)
...
length of chunk
struct guestfs_chunk (with data.data_len == 0)
The final chunk has the "data_len" field set to zero. Additionally a
flag is set in the final chunk to indicate either successful completion or
early cancellation.
At time of writing there are no functions that have more than one FileIn
parameter. However this is (theoretically) supported, by sending the sequence
of chunks for each FileIn parameter one after another (from left to right).
Both the library (sender)
and the daemon (receiver) may cancel the
transfer. The library does this by sending a chunk with a special flag set to
indicate cancellation. When the daemon sees this, it cancels the whole RPC,
does
not send any reply, and goes back to reading the next request.
The daemon may also cancel. It does this by writing a special word
"GUESTFS_CANCEL_FLAG" to the socket. The library listens for this
during the transfer, and if it gets it, it will cancel the transfer (it sends
a cancel chunk). The special word is chosen so that even if cancellation
happens right at the end of the transfer (after the library has finished
writing and has started listening for the reply), the "spurious"
cancel flag will not be confused with the reply message.
This protocol allows the transfer of arbitrary sized files (no 32 bit limit),
and also files where the size is not known in advance (eg. from pipes or
sockets). However the chunks are rather small
("GUESTFS_MAX_CHUNK_SIZE"), so that neither the library nor the
daemon need to keep much in memory.
FUNCTIONS THAT HAVE FILEOUT PARAMETERS
The protocol for FileOut parameters is exactly the same as for FileIn
parameters, but with the roles of daemon and library reversed.
total length (header + ret,
but not including the length word itself,
and not including the chunks)
struct guestfs_message_header (encoded as XDR)
struct guestfs_<foo>_ret (encoded as XDR)
sequence of chunks for FileOut param #0
sequence of chunks for FileOut param #1 etc.
INITIAL MESSAGE
When the daemon launches it sends an initial word
("GUESTFS_LAUNCH_FLAG") which indicates that the guest and daemon is
alive. This is what "guestfs_launch" waits for.
PROGRESS NOTIFICATION MESSAGES
The daemon may send progress notification messages at any time. These are
distinguished by the normal length word being replaced by
"GUESTFS_PROGRESS_FLAG", followed by a fixed size progress message.
The library turns them into progress callbacks (see
"GUESTFS_EVENT_PROGRESS") if there is a callback registered, or
discards them if not.
The daemon self-limits the frequency of progress messages it sends (see
"daemon/proto.c:notify_progress"). Not all calls generate progress
messages.
LIBGUESTFS VERSION NUMBERS¶
Since April 2010, libguestfs has started to make separate development and stable
releases, along with corresponding branches in our git repository. These
separate releases can be identified by version number:
even numbers for stable: 1.2.x, 1.4.x, ...
.-------- odd numbers for development: 1.3.x, 1.5.x, ...
|
v
1 . 3 . 5
^ ^
| |
| `-------- sub-version
|
`------ always '1' because we don't change the ABI
Thus "1.3.5" is the 5th update to the development branch
"1.3".
As time passes we cherry pick fixes from the development branch and backport
those into the stable branch, the effect being that the stable branch should
get more stable and less buggy over time. So the stable releases are ideal for
people who don't need new features but would just like the software to work.
Our criteria for backporting changes are:
- •
- Documentation changes which don't affect any code are
backported unless the documentation refers to a future feature which is
not in stable.
- •
- Bug fixes which are not controversial, fix obvious
problems, and have been well tested are backported.
- •
- Simple rearrangements of code which shouldn't affect how it
works get backported. This is so that the code in the two branches doesn't
get too far out of step, allowing us to backport future fixes more
easily.
- •
- We don't backport new features, new APIs, new tools
etc, except in one exceptional case: the new feature is required in order
to implement an important bug fix.
A new stable branch starts when we think the new features in development are
substantial and compelling enough over the current stable branch to warrant
it. When that happens we create new stable and development versions 1.N.0 and
1.(N+1).0 [N is even]. The new dot-oh release won't necessarily be so stable
at this point, but by backporting fixes from development, that branch will
stabilize over time.
EXTENDING LIBGUESTFS¶
ADDING A NEW API ACTION¶
Large amounts of boilerplate code in libguestfs (RPC, bindings, documentation)
are generated, and this makes it easy to extend the libguestfs API.
To add a new API action there are two changes:
- 1.
- You need to add a description of the call (name,
parameters, return type, tests, documentation) to
"generator/generator_actions.ml".
There are two sorts of API action, depending on whether the call goes
through to the daemon in the appliance, or is serviced entirely by the
library (see "ARCHITECTURE" above). "guestfs_sync" is
an example of the former, since the sync is done in the appliance.
"guestfs_set_trace" is an example of the latter, since a trace
flag is maintained in the handle and all tracing is done on the library
side.
Most new actions are of the first type, and get added to the
"daemon_functions" list. Each function has a unique procedure
number used in the RPC protocol which is assigned to that action when we
publish libguestfs and cannot be reused. Take the latest procedure number
and increment it.
For library-only actions of the second type, add to the
"non_daemon_functions" list. Since these functions are serviced
by the library and do not travel over the RPC mechanism to the daemon,
these functions do not need a procedure number, and so the procedure
number is set to "-1".
- 2.
- Implement the action (in C):
For daemon actions, implement the function "do_<name>" in
the "daemon/" directory.
For library actions, implement the function
"guestfs__<name>" (note: double underscore) in the
"src/" directory.
In either case, use another function as an example of what to do.
After making these changes, use "make" to compile.
Note that you don't need to implement the RPC, language bindings, manual pages
or anything else. It's all automatically generated from the OCaml description.
ADDING TESTS FOR AN API ACTION¶
You can supply zero or as many tests as you want per API call. The tests can
either be added as part of the API description
("generator/generator_actions.ml"), or in some rarer cases you may
want to drop a script into "tests/*/". Note that adding a script to
"tests/*/" is slower, so if possible use the first method.
The following describes the test environment used when you add an API test in
"generator_actions.ml".
The test environment has 4 block devices:
- "/dev/sda" 500MB
- General block device for testing.
- "/dev/sdb" 50MB
- "/dev/sdb1" is an ext2 filesystem used for
testing filesystem write operations.
- "/dev/sdc" 10MB
- Used in a few tests where two block devices are
needed.
- "/dev/sdd"
- ISO with fixed content (see
"images/test.iso").
To be able to run the tests in a reasonable amount of time, the libguestfs
appliance and block devices are reused between tests. So don't try testing
"guestfs_kill_subprocess" :-x
Each test starts with an initial scenario, selected using one of the
"Init*" expressions, described in
"generator/generator_types.ml". These initialize the disks mentioned
above in a particular way as documented in "generator_types.ml". You
should not assume anything about the previous contents of other disks that are
not initialized.
You can add a prerequisite clause to any individual test. This is a run-time
check, which, if it fails, causes the test to be skipped. Useful if testing a
command which might not work on all variations of libguestfs builds. A test
that has prerequisite of "Always" means to run unconditionally.
In addition, packagers can skip individual tests by setting environment
variables before running "make check".
SKIP_TEST_<CMD>_<NUM>=1
eg: "SKIP_TEST_COMMAND_3=1" skips test #3 of
"guestfs_command".
or:
SKIP_TEST_<CMD>=1
eg: "SKIP_TEST_ZEROFREE=1" skips all "guestfs_zerofree"
tests.
Packagers can run only certain tests by setting for example:
TEST_ONLY="vfs_type zerofree"
See "tests/c-api/tests.c" for more details of how these environment
variables work.
DEBUGGING NEW API ACTIONS¶
Test new actions work before submitting them.
You can use guestfish to try out new commands.
Debugging the daemon is a problem because it runs inside a minimal environment.
However you can fprintf messages in the daemon to stderr, and they will show
up if you use "guestfish -v".
Our C source code generally adheres to some basic code-formatting conventions.
The existing code base is not totally consistent on this front, but we do
prefer that contributed code be formatted similarly. In short, use
spaces-not-TABs for indentation, use 2 spaces for each indentation level, and
other than that, follow the K&R style.
If you use Emacs, add the following to one of one of your start-up files (e.g.,
~/.emacs), to help ensure that you get indentation right:
;;; In libguestfs, indent with spaces everywhere (not TABs).
;;; Exceptions: Makefile and ChangeLog modes.
(add-hook 'find-file-hook
'(lambda () (if (and buffer-file-name
(string-match "/libguestfs\\>"
(buffer-file-name))
(not (string-equal mode-name "Change Log"))
(not (string-equal mode-name "Makefile")))
(setq indent-tabs-mode nil))))
;;; When editing C sources in libguestfs, use this style.
(defun libguestfs-c-mode ()
"C mode with adjusted defaults for use with libguestfs."
(interactive)
(c-set-style "K&R")
(setq c-indent-level 2)
(setq c-basic-offset 2))
(add-hook 'c-mode-hook
'(lambda () (if (string-match "/libguestfs\\>"
(buffer-file-name))
(libguestfs-c-mode))))
Enable warnings when compiling (and fix any problems this finds):
./configure --enable-gcc-warnings
Useful targets are:
make syntax-check # checks the syntax of the C code
make check # runs the test suite
In the daemon code we have created custom printf formatters %Q and %R, which are
used to do shell quoting.
- %Q
- Simple shell quoted string. Any spaces or other shell
characters are escaped for you.
- %R
- Same as %Q except the string is treated as a path which is
prefixed by the sysroot.
For example:
asprintf (&cmd, "cat %R", path);
would produce "cat /sysroot/some\ path\ with\ spaces"
Note: Do
not use these when you are passing parameters to the
"command{,r,v,rv}()" functions. These parameters do NOT need to be
quoted because they are not passed via the shell (instead, straight to exec).
You probably want to use the "sysroot_path()" function however.
SUBMITTING YOUR NEW API ACTIONS¶
Submit patches to the mailing list:
<
http://www.redhat.com/mailman/listinfo/libguestfs> and CC to
rjones@redhat.com.
INTERNATIONALIZATION (I18N) SUPPORT¶
We support i18n (gettext anyhow) in the library.
However many messages come from the daemon, and we don't translate those at the
moment. One reason is that the appliance generally has all locale files
removed from it, because they take up a lot of space. So we'd have to readd
some of those, as well as copying our PO files into the appliance.
Debugging messages are never translated, since they are intended for the
programmers.
SOURCE CODE SUBDIRECTORIES¶
- "align"
- virt-alignment-scan(1) command and
documentation.
- "appliance"
- The libguestfs appliance, build scripts and so on.
- "cat"
- The virt-cat(1), virt-filesystems(1) and
virt-ls(1) commands and documentation.
- "contrib"
- Outside contributions, experimental parts.
- "daemon"
- The daemon that runs inside the libguestfs appliance and
carries out actions.
- "df"
- virt-df(1) command and documentation.
- "edit"
- virt-edit(1) command and documentation.
- "examples"
- C API example code.
- "fish"
- guestfish(1), the command-line shell, and various
shell scripts built on top such as virt-copy-in(1),
virt-copy-out(1), virt-tar-in(1),
virt-tar-out(1).
- "format"
- virt-format(1) command and documentation.
- "fuse"
- guestmount(1), FUSE (userspace filesystem) built on
top of libguestfs.
- "generator"
- The crucially important generator, used to automatically
generate large amounts of boilerplate C code for things like RPC and
bindings.
- "inspector"
- virt-inspector(1), the virtual machine image
inspector.
- "logo"
- Logo used on the website. The fish is called Arthur by the
way.
- "m4"
- M4 macros used by autoconf.
- "po"
- Translations of simple gettext strings.
- "po-docs"
- The build infrastructure and PO files for translations of
manpages and POD files. Eventually this will be combined with the
"po" directory, but that is rather complicated.
- "rescue"
- virt-rescue(1) command and documentation.
- "resize"
- virt-resize(1) command and documentation.
- "sparsify"
- virt-sparsify(1) command and documentation.
- "src"
- Source code to the C library.
- "sysprep"
- virt-sysprep(1) command and documentation.
- "test-tool"
- Test tool for end users to test if their qemu/kernel
combination will work with libguestfs.
- "tests"
- Tests.
- "tools"
- Command line tools written in Perl (virt-win-reg(1)
and many others).
- "csharp"
- "erlang"
- "gobject"
- "haskell"
- "java"
- "ocaml"
- "php"
- "perl"
- "python"
- "ruby"
- Language bindings.
MAKING A STABLE RELEASE¶
When we make a stable release, there are several steps documented here. See
"LIBGUESTFS VERSION NUMBERS" for general information about the
stable branch policy.
- •
- Check "make && make check" works on at
least Fedora, Debian and Ubuntu.
- •
- Finalize RELEASE-NOTES.
- •
- Update ROADMAP.
- •
- Run
"src/api-support/update-from-tarballs.sh".
- •
- Push and pull from Transifex.
Run:
tx push -s
to push the latest POT files to Transifex. Then run:
./tx-pull.sh
which is a wrapper to pull the latest translated "*.po"
files.
- •
- Create new stable and development directories under
<http://libguestfs.org/download>.
- •
- Create the branch in git:
git tag -a 1.XX.0 -m "Version 1.XX.0 (stable)"
git tag -a 1.YY.0 -m "Version 1.YY.0 (development)"
git branch stable-1.XX
git push origin tag 1.XX.0 1.YY.0 stable-1.XX
LIMITS¶
PROTOCOL LIMITS¶
Internally libguestfs uses a message-based protocol to pass API calls and their
responses to and from a small "appliance" (see "INTERNALS"
for plenty more detail about this). The maximum message size used by the
protocol is slightly less than 4 MB. For some API calls you may need to be
aware of this limit. The API calls which may be affected are individually
documented, with a link back to this section of the documentation.
A simple call such as "guestfs_cat" returns its result (the file data)
in a simple string. Because this string is at some point internally encoded as
a message, the maximum size that it can return is slightly under 4 MB. If the
requested file is larger than this then you will get an error.
In order to transfer large files into and out of the guest filesystem, you need
to use particular calls that support this. The sections "UPLOADING"
and "DOWNLOADING" document how to do this.
You might also consider mounting the disk image using our FUSE filesystem
support (
guestmount(1)).
MAXIMUM NUMBER OF DISKS¶
When using virtio disks (the default) the current limit is
25 disks.
Virtio itself consumes 1 virtual PCI slot per disk, and PCI is limited to 31
slots. However febootstrap only understands disks with names
"/dev/vda" through "/dev/vdz" (26 letters) and it reserves
one disk for its own purposes.
We are working to substantially raise this limit in future versions but it
requires complex changes to qemu.
In future versions of libguestfs it should also be possible to "hot
plug" disks (add and remove disks after calling
"guestfs_launch"). This also requires changes to qemu.
MAXIMUM NUMBER OF PARTITIONS PER DISK¶
Virtio limits the maximum number of partitions per disk to
15.
This is because it reserves 4 bits for the minor device number (thus
"/dev/vda", and "/dev/vda1" through
"/dev/vda15").
If you attach a disk with more than 15 partitions, the extra partitions are
ignored by libguestfs.
MAXIMUM SIZE OF A DISK¶
Probably the limit is between 2**63-1 and 2**64-1 bytes.
We have tested block devices up to 1 exabyte (2**60 or 1,152,921,504,606,846,976
bytes) using sparse files backed by an XFS host filesystem.
Although libguestfs probably does not impose any limit, the underlying host
storage will. If you store disk images on a host ext4 filesystem, then the
maximum size will be limited by the maximum ext4 file size (currently 16 TB).
If you store disk images as host logical volumes then you are limited by the
maximum size of an LV.
For the hugest disk image files, we recommend using XFS on the host for storage.
MAXIMUM SIZE OF A PARTITION¶
The MBR (ie. classic MS-DOS) partitioning scheme uses 32 bit sector numbers.
Assuming a 512 byte sector size, this means that MBR cannot address a
partition located beyond 2 TB on the disk.
It is recommended that you use GPT partitions on disks which are larger than
this size. GPT uses 64 bit sector numbers and so can address partitions which
are theoretically larger than the largest disk we could support.
MAXIMUM SIZE OF A FILESYSTEM, FILES, DIRECTORIES¶
This depends on the filesystem type. libguestfs itself does not impose any known
limit. Consult Wikipedia or the filesystem documentation to find out what
these limits are.
MAXIMUM UPLOAD AND DOWNLOAD¶
The API functions "guestfs_upload", "guestfs_download",
"guestfs_tar_in", "guestfs_tar_out" and the like allow
unlimited sized uploads and downloads.
INSPECTION LIMITS¶
The inspection code has several arbitrary limits on things like the size of
Windows Registry hive it will read, and the length of product name. These are
intended to stop a malicious guest from consuming arbitrary amounts of memory
and disk space on the host, and should not be reached in practice. See the
source code for more information.
ENVIRONMENT VARIABLES¶
- FEBOOTSTRAP_KERNEL
- FEBOOTSTRAP_MODULES
- These two environment variables allow the kernel that
libguestfs uses in the appliance to be selected. If $FEBOOTSTRAP_KERNEL is
not set, then the most recent host kernel is chosen. For more information
about kernel selection, see febootstrap-supermin-helper(8). This
feature is only available in febootstrap ≥ 3.8.
- LIBGUESTFS_APPEND
- Pass additional options to the guest kernel.
- LIBGUESTFS_DEBUG
- Set "LIBGUESTFS_DEBUG=1" to enable verbose
messages. This has the same effect as calling "guestfs_set_verbose
(g, 1)".
- LIBGUESTFS_MEMSIZE
- Set the memory allocated to the qemu process, in megabytes.
For example:
LIBGUESTFS_MEMSIZE=700
- LIBGUESTFS_PATH
- Set the path that libguestfs uses to search for a supermin
appliance. See the discussion of paths in section "PATH"
above.
- LIBGUESTFS_QEMU
- Set the default qemu binary that libguestfs uses. If not
set, then the qemu which was found at compile time by the configure script
is used.
See also "QEMU WRAPPERS" above.
- LIBGUESTFS_TRACE
- Set "LIBGUESTFS_TRACE=1" to enable command
traces. This has the same effect as calling "guestfs_set_trace (g,
1)".
- TMPDIR
- Location of temporary directory, defaults to
"/tmp" except for the cached supermin appliance which defaults
to "/var/tmp".
If libguestfs was compiled to use the supermin appliance then the real
appliance is cached in this directory, shared between all handles
belonging to the same EUID. You can use $TMPDIR to configure another
directory to use in case "/var/tmp" is not large enough.
SEE ALSO¶
guestfs-examples(3),
guestfs-erlang(3),
guestfs-java(3),
guestfs-ocaml(3),
guestfs-perl(3),
guestfs-python(3),
guestfs-ruby(3),
guestfish(1),
guestmount(1),
virt-alignment-scan(1),
virt-cat(1),
virt-copy-in(1),
virt-copy-out(1),
virt-df(1),
virt-edit(1),
virt-filesystems(1),
virt-format(1),
virt-inspector(1),
virt-list-filesystems(1),
virt-list-partitions(1),
virt-ls(1),
virt-make-fs(1),
virt-rescue(1),
virt-resize(1),
virt-sparsify(1),
virt-sysprep(1),
virt-tar(1),
virt-tar-in(1),
virt-tar-out(1),
virt-win-reg(1),
guestfs-faq(1),
guestfs-performance(1),
guestfs-testing(1),
libguestfs-test-tool(1),
libguestfs-make-fixed-appliance(1),
febootstrap(1),
febootstrap-supermin-helper(8),
qemu(1),
hivex(3),
stap(1), <
http://libguestfs.org/>.
Tools with a similar purpose:
fdisk(8),
parted(8),
kpartx(8),
lvm(8),
disktype(1).
BUGS¶
To get a list of bugs against libguestfs use this link:
<
https://bugzilla.redhat.com/buglist.cgi?component=libguestfs&product=Virtualization+Tools>
To report a new bug against libguestfs use this link:
<
https://bugzilla.redhat.com/enter_bug.cgi?component=libguestfs&product=Virtualization+Tools>
When reporting a bug, please check:
- •
- That the bug hasn't been reported already.
- •
- That you are testing a recent version.
- •
- Describe the bug accurately, and give a way to reproduce
it.
- •
- Run libguestfs-test-tool and paste the complete,
unedited output into the bug report.
AUTHORS¶
Richard W.M. Jones ("rjones at redhat dot com")
COPYRIGHT¶
Copyright (C) 2009-2012 Red Hat Inc. <
http://libguestfs.org/>
This library is free software; you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License as published by the Free
Software Foundation; either version 2 of the License, or (at your option) any
later version.
This library is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
details.
You should have received a copy of the GNU Lesser General Public License along
with this library; if not, write to the Free Software Foundation, Inc., 51
Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA