NAME¶
File::Path - Create or remove directory trees
VERSION¶
This document describes version 2.08 of File::Path, released 2009-10-04.
SYNOPSIS¶
use File::Path qw(make_path remove_tree);
make_path('foo/bar/baz', '/zug/zwang');
make_path('foo/bar/baz', '/zug/zwang', {
verbose => 1,
mode => 0711,
});
remove_tree('foo/bar/baz', '/zug/zwang');
remove_tree('foo/bar/baz', '/zug/zwang', {
verbose => 1,
error => \my $err_list,
});
# legacy (interface promoted before v2.00)
mkpath('/foo/bar/baz');
mkpath('/foo/bar/baz', 1, 0711);
mkpath(['/foo/bar/baz', 'blurfl/quux'], 1, 0711);
rmtree('foo/bar/baz', 1, 1);
rmtree(['foo/bar/baz', 'blurfl/quux'], 1, 1);
# legacy (interface promoted before v2.06)
mkpath('foo/bar/baz', '/zug/zwang', { verbose => 1, mode => 0711 });
rmtree('foo/bar/baz', '/zug/zwang', { verbose => 1, mode => 0711 });
DESCRIPTION¶
This module provide a convenient way to create directories of arbitrary depth
and to delete an entire directory subtree from the filesystem.
The following functions are provided:
- make_path( $dir1, $dir2, .... )
- make_path( $dir1, $dir2, ...., \%opts )
- The "make_path" function creates the given
directories if they don't exists before, much like the Unix command
"mkdir -p".
The function accepts a list of directories to be created. Its behaviour may
be tuned by an optional hashref appearing as the last parameter on the
call.
The function returns the list of directories actually created during the
call; in scalar context the number of directories created.
The following keys are recognised in the option hash:
- mode => $num
- The numeric permissions mode to apply to each created
directory (defaults to 0777), to be modified by the current
"umask". If the directory already exists (and thus does not need
to be created), the permissions will not be modified.
"mask" is recognised as an alias for this parameter.
- verbose => $bool
- If present, will cause "make_path" to print the
name of each directory as it is created. By default nothing is
printed.
- error => \$err
- If present, it should be a reference to a scalar. This
scalar will be made to reference an array, which will be used to store any
errors that are encountered. See the "ERROR HANDLING" section
for more information.
If this parameter is not used, certain error conditions may raise a fatal
error that will cause the program will halt, unless trapped in an
"eval" block.
- owner => $owner
- user => $owner
- uid => $owner
- If present, will cause any created directory to be owned by
$owner. If the value is numeric, it will be interpreted as a uid,
otherwise as username is assumed. An error will be issued if the username
cannot be mapped to a uid, or the uid does not exist, or the process lacks
the privileges to change ownership.
Ownwership of directories that already exist will not be changed.
"user" and "uid" are aliases of "owner".
- group => $group
- If present, will cause any created directory to be owned by
the group $group. If the value is numeric, it will be interpreted as a
gid, otherwise as group name is assumed. An error will be issued if the
group name cannot be mapped to a gid, or the gid does not exist, or the
process lacks the privileges to change group ownership.
Group ownwership of directories that already exist will not be changed.
make_path '/var/tmp/webcache', {owner=>'nobody', group=>'nogroup'};
- mkpath( $dir )
- mkpath( $dir, $verbose, $mode )
- mkpath( [$dir1, $dir2,...], $verbose, $mode )
- mkpath( $dir1, $dir2,..., \%opt )
- The mkpath() function provide the legacy interface
of make_path() with a different interpretation of the arguments
passed. The behaviour and return value of the function is otherwise
identical to make_path().
- remove_tree( $dir1, $dir2, .... )
- remove_tree( $dir1, $dir2, ...., \%opts )
- The "remove_tree" function deletes the given
directories and any files and subdirectories they might contain, much like
the Unix command "rm -r" or "del /s" on Windows.
The function accepts a list of directories to be removed. Its behaviour may
be tuned by an optional hashref appearing as the last parameter on the
call.
The functions returns the number of files successfully deleted.
The following keys are recognised in the option hash:
- verbose => $bool
- If present, will cause "remove_tree" to print the
name of each file as it is unlinked. By default nothing is printed.
- safe => $bool
- When set to a true value, will cause
"remove_tree" to skip the files for which the process lacks the
required privileges needed to delete files, such as delete privileges on
VMS. In other words, the code will make no attempt to alter file
permissions. Thus, if the process is interrupted, no filesystem object
will be left in a more permissive mode.
- keep_root => $bool
- When set to a true value, will cause all files and
subdirectories to be removed, except the initially specified directories.
This comes in handy when cleaning out an application's scratch directory.
remove_tree( '/tmp', {keep_root => 1} );
- result => \$res
- If present, it should be a reference to a scalar. This
scalar will be made to reference an array, which will be used to store all
files and directories unlinked during the call. If nothing is unlinked,
the array will be empty.
remove_tree( '/tmp', {result => \my $list} );
print "unlinked $_\n" for @$list;
This is a useful alternative to the "verbose" key.
- error => \$err
- If present, it should be a reference to a scalar. This
scalar will be made to reference an array, which will be used to store any
errors that are encountered. See the "ERROR HANDLING" section
for more information.
Removing things is a much more dangerous proposition than creating things.
As such, there are certain conditions that "remove_tree" may
encounter that are so dangerous that the only sane action left is to kill
the program.
Use "error" to trap all that is reasonable (problems with
permissions and the like), and let it die if things get out of hand. This
is the safest course of action.
- rmtree( $dir )
- rmtree( $dir, $verbose, $safe )
- rmtree( [$dir1, $dir2,...], $verbose, $safe )
- rmtree( $dir1, $dir2,..., \%opt )
- The rmtree() function provide the legacy interface
of remove_tree() with a different interpretation of the arguments
passed. The behaviour and return value of the function is otherwise
identical to remove_tree().
ERROR HANDLING¶
- NOTE:
- The following error handling mechanism is considered
experimental and is subject to change pending feedback from users.
If "make_path" or "remove_tree" encounter an error, a
diagnostic message will be printed to "STDERR" via "carp"
(for non-fatal errors), or via "croak" (for fatal errors).
If this behaviour is not desirable, the "error" attribute may be used
to hold a reference to a variable, which will be used to store the
diagnostics. The variable is made a reference to an array of hash references.
Each hash contain a single key/value pair where the key is the name of the
file, and the value is the error message (including the contents of $! when
appropriate). If a general error is encountered the diagnostic key will be
empty.
An example usage looks like:
remove_tree( 'foo/bar', 'bar/rat', {error => \my $err} );
if (@$err) {
for my $diag (@$err) {
my ($file, $message) = %$diag;
if ($file eq '') {
print "general error: $message\n";
}
else {
print "problem unlinking $file: $message\n";
}
}
}
else {
print "No error encountered\n";
}
Note that if no errors are encountered, $err will reference an empty array. This
means that $err will always end up TRUE; so you need to test @$err to
determine if errors occured.
NOTES¶
"File::Path" blindly exports "mkpath" and "rmtree"
into the current namespace. These days, this is considered bad style, but to
change it now would break too much code. Nonetheless, you are invited to
specify what it is you are expecting to use:
use File::Path 'rmtree';
The routines "make_path" and "remove_tree" are
not
exported by default. You must specify which ones you want to use.
use File::Path 'remove_tree';
Note that a side-effect of the above is that "mkpath" and
"rmtree" are no longer exported at all. This is due to the way the
"Exporter" module works. If you are migrating a codebase to use the
new interface, you will have to list everything explicitly. But that's just
good practice anyway.
use File::Path qw(remove_tree rmtree);
API CHANGES
The API was changed in the 2.0 branch. For a time, "mkpath" and
"rmtree" tried, unsuccessfully, to deal with the two different
calling mechanisms. This approach was considered a failure.
The new semantics are now only available with "make_path" and
"remove_tree". The old semantics are only available through
"mkpath" and "rmtree". Users are strongly encouraged to
upgrade to at least 2.08 in order to avoid surprises.
SECURITY CONSIDERATIONS
There were race conditions 1.x implementations of File::Path's
"rmtree" function (although sometimes patched depending on the OS
distribution or platform). The 2.0 version contains code to avoid the problem
mentioned in CVE-2002-0435.
See the following pages for more information:
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=286905
http://www.nntp.perl.org/group/perl.perl5.porters/2005/01/msg97623.html
http://www.debian.org/security/2005/dsa-696
Additionally, unless the "safe" parameter is set (or the third
parameter in the traditional interface is TRUE), should a
"remove_tree" be interrupted, files that were originally in
read-only mode may now have their permissions set to a read-write (or
"delete OK") mode.
DIAGNOSTICS¶
FATAL errors will cause the program to halt ("croak"), since the
problem is so severe that it would be dangerous to continue. (This can always
be trapped with "eval", but it's not a good idea. Under the
circumstances, dying is the best thing to do).
SEVERE errors may be trapped using the modern interface. If the they are not
trapped, or the old interface is used, such an error will cause the program
will halt.
All other errors may be trapped using the modern interface, otherwise they will
be "carp"ed about. Program execution will not be halted.
- mkdir [path]: [errmsg] (SEVERE)
- "make_path" was unable to create the path.
Probably some sort of permissions error at the point of departure, or
insufficient resources (such as free inodes on Unix).
- No root path(s) specified
- "make_path" was not given any paths to create.
This message is only emitted if the routine is called with the traditional
interface. The modern interface will remain silent if given nothing to
do.
- No such file or directory
- On Windows, if "make_path" gives you this
warning, it may mean that you have exceeded your filesystem's maximum path
length.
- cannot fetch initial working directory: [errmsg]
- "remove_tree" attempted to determine the initial
directory by calling "Cwd::getcwd", but the call failed for some
reason. No attempt will be made to delete anything.
- cannot stat initial working directory: [errmsg]
- "remove_tree" attempted to stat the initial
directory (after having successfully obtained its name via
"getcwd"), however, the call failed for some reason. No attempt
will be made to delete anything.
- cannot chdir to [dir]: [errmsg]
- "remove_tree" attempted to set the working
directory in order to begin deleting the objects therein, but was
unsuccessful. This is usually a permissions issue. The routine will
continue to delete other things, but this directory will be left
intact.
- directory [dir] changed before chdir, expected dev=[n]
ino=[n], actual dev=[n] ino=[n], aborting. (FATAL)
- "remove_tree" recorded the device and inode of a
directory, and then moved into it. It then performed a "stat" on
the current directory and detected that the device and inode were no
longer the same. As this is at the heart of the race condition problem,
the program will die at this point.
- cannot make directory [dir] read+writeable: [errmsg]
- "remove_tree" attempted to change the permissions
on the current directory to ensure that subsequent unlinkings would not
run into problems, but was unable to do so. The permissions remain as they
were, and the program will carry on, doing the best it can.
- cannot read [dir]: [errmsg]
- "remove_tree" tried to read the contents of the
directory in order to acquire the names of the directory entries to be
unlinked, but was unsuccessful. This is usually a permissions issue. The
program will continue, but the files in this directory will remain after
the call.
- cannot reset chmod [dir]: [errmsg]
- "remove_tree", after having deleted everything in
a directory, attempted to restore its permissions to the original state
but failed. The directory may wind up being left behind.
- cannot remove [dir] when cwd is [dir]
- The current working directory of the program is
/some/path/to/here and you are attempting to remove an ancestor,
such as /some/path. The directory tree is left untouched.
The solution is to "chdir" out of the child directory to a place
outside the directory tree to be removed.
- cannot chdir to [parent-dir] from [child-dir]: [errmsg],
aborting. (FATAL)
- "remove_tree", after having deleted everything
and restored the permissions of a directory, was unable to chdir back to
the parent. The program halts to avoid a race condition from
occurring.
- cannot stat prior working directory [dir]: [errmsg],
aborting. (FATAL)
- "remove_tree" was unable to stat the parent
directory after have returned from the child. Since there is no way of
knowing if we returned to where we think we should be (by comparing device
and inode) the only way out is to "croak".
- previous directory [parent-dir] changed before entering
[child-dir], expected dev=[n] ino=[n], actual dev=[n] ino=[n], aborting.
(FATAL)
- When "remove_tree" returned from deleting files
in a child directory, a check revealed that the parent directory it
returned to wasn't the one it started out from. This is considered a sign
of malicious activity.
- cannot make directory [dir] writeable: [errmsg]
- Just before removing a directory (after having successfully
removed everything it contained), "remove_tree" attempted to set
the permissions on the directory to ensure it could be removed and failed.
Program execution continues, but the directory may possibly not be
deleted.
- cannot remove directory [dir]: [errmsg]
- "remove_tree" attempted to remove a directory,
but failed. This may because some objects that were unable to be removed
remain in the directory, or a permissions issue. The directory will be
left behind.
- cannot restore permissions of [dir] to [0nnn]:
[errmsg]
- After having failed to remove a directory,
"remove_tree" was unable to restore its permissions from a
permissive state back to a possibly more restrictive setting. (Permissions
given in octal).
- cannot make file [file] writeable: [errmsg]
- "remove_tree" attempted to force the permissions
of a file to ensure it could be deleted, but failed to do so. It will,
however, still attempt to unlink the file.
- cannot unlink file [file]: [errmsg]
- "remove_tree" failed to remove a file. Probably a
permissions issue.
- cannot restore permissions of [file] to [0nnn]:
[errmsg]
- After having failed to remove a file,
"remove_tree" was also unable to restore the permissions on the
file to a possibly less permissive setting. (Permissions given in
octal).
- unable to map [owner] to a uid, ownership not
changed");
- "make_path" was instructed to give the ownership
of created directories to the symbolic name [owner], but
"getpwnam" did not return the corresponding numeric uid. The
directory will be created, but ownership will not be changed.
- unable to map [group] to a gid, group ownership not
changed
- "make_path" was instructed to give the group
ownership of created directories to the symbolic name [group], but
"getgrnam" did not return the corresponding numeric gid. The
directory will be created, but group ownership will not be changed.
SEE ALSO¶
- •
- File::Remove
Allows files and directories to be moved to the Trashcan/Recycle Bin (where
they may later be restored if necessary) if the operating system supports
such functionality. This feature may one day be made available directly in
"File::Path".
- •
- File::Find::Rule
When removing directory trees, if you want to examine each file to decide
whether to delete it (and possibly leaving large swathes alone),
File::Find::Rule offers a convenient and flexible approach to
examining directory trees.
BUGS¶
Please report all bugs on the RT queue:
http://rt.cpan.org/NoAuth/Bugs.html?Dist=File-Path
<
http://rt.cpan.org/NoAuth/Bugs.html?Dist=File-Path>
ACKNOWLEDGEMENTS¶
Paul Szabo identified the race condition originally, and Brendan O'Dea wrote an
implementation for Debian that addressed the problem. That code was used as a
basis for the current code. Their efforts are greatly appreciated.
Gisle Aas made a number of improvements to the documentation for 2.07 and his
advice and assistance is also greatly appreciated.
AUTHORS¶
Tim Bunce and Charles Bailey. Currently maintained by David Landgren <
david@landgren.net>.
COPYRIGHT¶
This module is copyright (C) Charles Bailey, Tim Bunce and David Landgren
1995-2009. All rights reserved.
LICENSE¶
This library is free software; you can redistribute it and/or modify it under
the same terms as Perl itself.