.TH "HUMFSIFY" "1" 
.SH "NAME" 
humfsify \(em convert a directory to the format needed by the UML 
humfs file system 
.SH "SYNOPSIS" 
.PP 
\fBhumfsify\fR [user]  [group]  [size]  
.SH "DESCRIPTION" 
.PP 
This manual page documents briefly the 
\fBhumfsify\fR command. 
.PP 
This manual page was written for the \fBDebian GNU/Linux\fP distribution 
because the original program does not have a manual page. 
Instead, it has documentation in HTML format; see below. 
.PP 
\fBhumfsify\fR is a Perl script necessary to 
convert a directory to a format expected by the UML humfs file system. 
 
.SH "HISTORY" 
.PP 
UMLFS was born with the idea to substitute the Hostfs 
implementation with a proper one for the UML purpose: when you 
manage files with Hostfs within UML you need to work with 
two different permission layers (the Host one and the UML one), 
which have different ideas of ownerships. 
.PP 
This becomes evident when you need to 
create a file as a non-root user on UML: you first need to interact 
with the UML file system implementation, and then with the host side. 
.PP 
The result of a file creation on a mounted hostfs file system 
is not what you expected: you can see that the file permissions refer to 
the Host side user rather than the UML creator. 
.PP 
The Host side user is to be intended as the UML instance 
launcher, meanwhile the UML side user is the one you used to log in 
the UML instance. 
.PP 
You can encounter a more-critical problem when creating a 
device node, operation that usually requires root privileges: you 
used a common user to launch the UML and, since the operation is 
done on the Host, it fails, even if you logged in as root. 
.PP 
Thus you need a set of tools which requires to bypass the 
Hostfs permission checks on the Host side: this is done by 
separating the file permissions and the ownership from the host's 
files. This is the concept behind the HumFs and its humfsify 
implementation. 
.SH "ARGUMENTS" 
.IP "\fBuser\fP" 10 
This is the user that needs to 'convert' a directory to the UML 
file system to use UML.  This is the host user who 
will be using this filesystem from within UML.  It 
may be specified as either a user name or a numeric 
user id. 
.IP "\fBgroup\fP" 10 
This is the group which your UML user belongs to. 
This may be either a group name or a numeric group id 
.IP "\fBsize\fP" 10 
This is the size of the file system as seen within the 
UML instance. It must be expressed in Gigabytes ("G"), 
Megabytes ("M"), or KiloBytes ("K"). 
.SH "EXAMPLES" 
.PP 
Create a directory on the host and mount it with humfsify 
.PP 
host% \fBmkdir your-humfs-dir\fR 
.PP 
host% \fBcd humfs-dir\fR 
.PP 
Within this directory create a new one where you would like to have 
a UML-like hierarchy, i.e. you can loop-mount an UML rootfs 
.PP 
host% \fBmkdir dir-to-be-humsified\fR 
.PP 
host# \fBmount \-o loop rootfs /mnt\fR 
.PP 
host% \fBcp \-a /mnt dir-to-be-humsified/data\fR 
.PP 
host# \fBhumfsify user group 512M\fR 
.PP 
Then verify it on UML and mount the humfsified 
directory: 
.PP 
UML# \fBmount none /your-uml-host \-t humfs \-o 
.../dir-to-be-humfsified\fR 
.PP 
where '/your-uml-mount-point' is the mount point on UML for 
the humfsified file system, and .../dir-to-be-humfsified is  
the humfsified directory in the example above. The '\-t' mount option  
specifies that the file system is to be mounted as 'humfs'. 
.SH "SEE ALSO" 
.PP 
The \fIHostFs (link to URL http://user-mode-linux.sourceforge.net/new/hostfs.html) \fR usage explanation within the 
User-Mode-Linux Web Site 
.SH "AUTHOR" 
.PP 
humfsify was written by Jeff Dike. 
.PP 
This manual page was written by Stefano Melchior stefano.melchior@openlabs.it for 
the \fBDebian GNU/Linux\fP system, based on material in the Official User Mode 
Linux Web Site. 
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