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e2fsimage(1)							  e2fsimage(1)

NAME
       e2fsimage  -  create  and populate an ext2 filesystem image as non-root
       user

SYNOPSIS
       e2fsimage  [-f imgfile]	[-d rootdir]   [-u uid]	  [-g gid]   [-D file]
       [-U file] [-P file] [-p] [-v] [-n] [-s size]

DESCRIPTION
       e2fsimage  creates  an ext2 filesystem image by recursively copying the
       files from the existing directory structure rootdir to the image-file.

       Supported filetypes are: regular files, directorys,  hard-links,	 soft-
       links,  block  special  devices,	 character  special devices and fifos.
       Hard links are resolved to result in hard links in the image.  The con‐
       tent (target) of softlinks is copied “ as-is ” and will not be resolved
       or altered in any way.

       The usual way to create ext2 filesystem images  for  initial  ramdisks,
       boot-floppys or bootable CDs is to create an image with eg.

       1    dd if=/dev/zero of=e2img bs=1024 count=4096
       2    mke2fs -F e2img
       3    mount -o loop e2img mounpoint
       4    cp -r rootdir/* mountpoint

       At least the last 2 commands must be executed as root.  In order to set
       the different ownerships (usually  root)	 and  to  create  the  special
       device files root permissions are also needed.

       Since  all  this results in a file that may belong to an ordinary user,
       this file can be created and filled with the  filesystem	 structure  by
       her.  This application manages to create such an image as ordinary user
       without sudo or suid-root bit set.  Of course suid-root programs in the
       filesystem  image  are  possible	 by  making them suid-user.  When this
       files are copied, the user is set to root and there you have your suid-
       root program.
       It is also not mandatory to have the rootdir on an ext2 filesystem.

OPTIONS
       -d rootdir
	      The  content of the filesystemimage is a recursive copy of root‐
	      dir.  All files are copied while preserving all  attributes  but
	      the  uid/gid.   They will usually be set to root.root.  This can
	      be overwritten with the -u and -g options respectively

       -D devicefile
	      The devicefile contains all special devices to be	 created,  see
	      DEVICES.
	      The default filename is .DEVICES.

       -U uidgidfile
	      The  uidgidfile contains the uids and gids different from 0, see
	      USERS.
	      The default filename is .UIDGID.

       -P passwd
	      The password file in this parameter  is  used  to	 convert  user
	      names  to	 uids  and gids.  It tries to use the default in root‐
	      dir/etc/passwd, if it is omitted.

       -G group
	      The group file in this parameter is used to convert group	 names
	      to  gids.	  It tries to use the default in rootdir/etc/group, if
	      it is omitted.

       -f imgfile
	      This is the target file for the filesystem  image.  An  existing
	      file will be overwritten as long as -n is not given.

       -g gid Change  the  default group id from 0 to gid.  Until now there is
	      only 1 gid for all files supported. If you need  different  gids
	      for different files, take a look at USERS

       -n     This option allows to reuse an existing filesystem image defined
	      by -f The existing content is not	 modified  by  any  means  but
	      there may not exist a file with the same name as a newly created
	      one.

       -p     Preserve original file owner. If	this  option  is  omitted  all
	      files  in	 the  image will belong to root. (This is usually what
	      you want)

       -s size
	      When the filesystem is created the  size	will  be  size	Kbytes
	      large. The default is 4096 kilo bytes.

       -u uid Change  the  default  user-id from 0 to uid.  Until now there is
	      only 1 uid for all files supported. If you need  different  uids
	      look at the section USERS

       -v     Be more verbose.

DEVICES
       Usually	the  devices  are  created using mknod by root. Obviously this
       would absurd the existence of e2fsimage to be a non-root tool. A device
       special	file called .DEVICES can be placed in every directory (usually
       dev ) that will contain device special files. The format of  this  file
       is:

       <name> <type> <major> <minor> [ <mode> [ <uid> [ <gid> ]]]

       name   the name of the file like ttyS0

       type   Actually	supported are c,u for character special devices, b for
	      block special devices and p,f for fifos.

       major minor.
	      This are the major and minor numbers of the device

       mode   The access mode for the file like 0644.  The  default  mode  for
	      devices is 0600 if mode is omitted.

       uid    The uid of the device, 0 if omitted.

       gid    The gid of the device, 0 if omitted.

       A  call to mknod like mknod -m 0600 ttyS1 c 4 65 would result in a line
       in dev/.DEVICES as "ttyS1 c 4 65 0600"

USERS
       Every directory may contain a file named .UIDGID . This filename can be
       changed by using the -U option. The format of this file is:

       <name> <uid> [ <gid> ]

       <name> <username> [ <groupname> ]

       If  <name>  is  ".",  then the owner and group information will be kept
       recursively for all files and  directorys  below.   For	a  "chown  500
       /home/user" one would write "user 500" to "home/.UIDGID and have such a
       directory "home/user" of course. For a "chown -R	 500  /home/user"  one
       would write a ". 500" to "home/user/.UIDGID".  Userid information given
       in .UIDGID overrides user info in .DEVICES.

       If the uid entry is not numeric it will be resolved  by	using  passwd,
       provided	 by  the  option  -P.  In this case the gid is also taken from
       passwd , if the groupname is omitted.  If the  groupname	 is  provided,
       the group file from -G is used to resolve the gid.

       name   is the name of the file.

       uid    is the numeric userid of the file.

       gid    is the numeric groupid of the file. It will be zero if omitted.

       username
	      is the user name of the file owner, resolved by passwd.

       groupname
	      is the group name of the file, resolved by group.

BUGS
       Bugs ?

SEE ALSO
       mke2fs(8)

AUTHOR
       This program was written by
       Christian Hohnstaedt <christian@hohnstaedt.de>
       The project homepage is http://www.hohnstaedt.de/e2fsimage

0.2.2				   June 2009			  e2fsimage(1)
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