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.\" $OpenBSD: chroot.8,v 1.15 2015/05/19 16:05:12 millert Exp $
.\"
.\" Copyright (c) 1988, 1991, 1993
.\" The Regents of the University of California. All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\" notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in the
.\" documentation and/or other materials provided with the distribution.
.\" 3. Neither the name of the University nor the names of its contributors
.\" may be used to endorse or promote products derived from this software
.\" without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\" from: @(#)chroot.8 8.1 (Berkeley) 6/9/93
.\"
.Dd $Mdocdate: May 19 2015 $
.Dt CHROOT 8
.Os
.Sh NAME
.Nm chroot
.Nd change root directory
.Sh SYNOPSIS
.Nm chroot
.Op Fl g Ar group,group,...
.Op Fl u Ar user
.Ar newroot
.Op Ar command
.Sh DESCRIPTION
The
.Nm
command changes its root directory to the supplied directory
.Ar newroot
and executes
.Ar command ,
if supplied, or an interactive copy of the user's shell.
.Pp
The
.Nm
command is restricted to the superuser.
.Pp
The options are as follows:
.Bl -tag -width Ds
.It Fl g Ar group,group,...
Override the primary and supplemental group IDs.
The primary group ID is set to the first group in the list.
Any remaining groups are placed in the supplemental group ID vector.
Each group listed must exist in the
.Xr group 5
databases.
.It Fl u Ar user
Set user ID to
.Ar user
(which must exist in the
.Xr passwd 5
database).
The primary and supplemental group IDs will be set based on the user's
entries in the
.Xr passwd 5
and
.Xr group 5
databases unless overridden by the
.Fl g
option.
Additional settings may be applied as specified in
.Xr login.conf 5
depending on
.Ar user Ns 's
login class.
.El
.Sh ENVIRONMENT
.Bl -tag -width SHELL
.It Ev SHELL
If set,
the string specified by
.Ev SHELL
is interpreted as the name of
the shell to execute.
If the variable
.Ev SHELL
is not set,
.Pa /bin/sh
is used.
.El
.Sh SEE ALSO
.Xr ldd 1 ,
.Xr group 5 ,
.Xr login.conf 5 ,
.Xr passwd 5 ,
.Xr environ 7
.Sh HISTORY
The
.Nm
utility first appeared in
.Bx 4.3 Reno .
.Sh CAVEATS
.Nm
should never be installed setuid root, as it would then be possible
to exploit the program to gain root privileges.
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