HUMFSIFY(1)						      General Commands Manual						       HUMFSIFY(1)

NAME

       humfsify -- convert a directory to the format needed by the UML humfs file system

SYNOPSIS

       humfsify [user]	[group]  [size]

DESCRIPTION

       This manual page documents briefly the humfsify command.

       This  manual  page was written for the Debian GNU/Linux distribution because the original program does not have a manual page.  Instead, it
       has documentation in HTML format; see below.

       humfsify is a Perl script necessary to convert a directory to a format expected by the UML humfs file system.

HISTORY

       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 own-
       erships.

       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  imple-
       mentation, and then with the host side.

       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.

       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.

       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.

       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.

ARGUMENTS

       user	 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.

       group	 This is the group which your UML user belongs to.  This may be either a group name or a numeric group id

       size	 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").

EXAMPLES

       Create a directory on the host and mount it with humfsify

       host% mkdir your-humfs-dir

       host% cd humfs-dir

       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

       host% mkdir dir-to-be-humsified

       host# mount -o loop rootfs /mnt

       host% cp -a /mnt dir-to-be-humsified/data

       host# humfsify user group 512M

       Then verify it on UML and mount the humfsified directory:

       UML# mount none /your-uml-host -t humfs -o

       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'.

SEE ALSO

       The HostFs (link to URL http://user-mode-linux.sourceforge.net/new/hostfs.html)	usage explanation within the User-Mode-Linux Web Site

AUTHOR

       humfsify was written by Jeff Dike.

       This manual page was written by Stefano Melchior stefano.melchior@openlabs.it for the Debian GNU/Linux system, based  on  material  in  the
       Official User Mode Linux Web Site.

																       HUMFSIFY(1)