chroot(1M)							    chroot(1M)

NAME    [Toc]    [Back]

     chroot - change root directory for	a command

SYNOPSIS    [Toc]    [Back]

     chroot newroot command

DESCRIPTION    [Toc]    [Back]

     chroot causes the given command to	be executed relative to	the new	root,
     newroot.  The meaning of any initial slashes (/) in the pathnames is
     changed for the command and any of	its child processes to newroot.
     Furthermore, upon execution, the initial working directory	is newroot.

     If	you redirect the output	of the command to a file:

	  chroot newroot command <b>> x

     chroot creates the	file x relative	to the original	root of	the command,
     not the new one.

     The new root pathname is always relative to the current root; even	if a
     chroot is currently in effect, the	newroot	argument is relative to	the
     current root of the running process.

     This command can be run only by the superuser.

CAVEAT    [Toc]    [Back]

     In	order to execute programs that use shared libraries, the following
     directories and their contents must be present in the new root directory.

     /lib and /lib32
		  These	directories must contain the run-time loader (/lib/rld
		  and/or /lib32/rld) and any shared object files needed	by
		  your applications (usually including libc.so.1).  That means
		  it must normally be in /lib and a symlink in /usr/lib	to
		  ../../lib/libc.so.1P (and often the same for /usr/lib32 to
		  ../../lib32/libc.so.1).

     ./dev	  The run-time loader needs the	zero device in order to	work
		  correctly.  /dev/zero	is also	needed;	make it	readonly (mode
		  444).

     A chroot can also be accomplished when users login	by prefixing the shell
     field of their password entry with	a *, See the passwd(4) man page	for
     more info.

SEE ALSO    [Toc]    [Back]

     cd(1), chroot(2), ftpd(1m)	(for more comments on issues in	setting	up
     chroot'ed environments), passwd(4)







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chroot(1M)							    chroot(1M)



NOTES
     Exercise extreme caution when referencing device files in the new root
     filesystem.

     When using	chroot,	with commands that are dynamically linked, all of the
     libraries required	must be	in the chroot'ed environment.  The system will
     usually log a message in /var/adm/SYSLOG if some libraries	or rld are not
     found.


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