1.\" $NetBSD: chroot.8,v 1.10 2001/03/19 03:41:42 lukem Exp $ 2.\" 3.\" Copyright (c) 1988, 1991, 1993 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. All advertising materials mentioning features or use of this software 15.\" must display the following acknowledgement: 16.\" This product includes software developed by the University of 17.\" California, Berkeley and its contributors. 18.\" 4. Neither the name of the University nor the names of its contributors 19.\" may be used to endorse or promote products derived from this software 20.\" without specific prior written permission. 21.\" 22.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32.\" SUCH DAMAGE. 33.\" 34.\" from: @(#)chroot.8 8.1 (Berkeley) 6/9/93 35.\" 36.Dd October 6, 1998 37.Dt CHROOT 8 38.Os 39.Sh NAME 40.Nm chroot 41.Nd change root directory 42.Sh SYNOPSIS 43.Nm 44.Op Fl u Ar user 45.Op Fl g Ar group 46.Op Fl G Ar group,group,... 47.Ar newroot 48.Op Ar command 49.Sh DESCRIPTION 50The 51.Nm 52command changes its root directory to the supplied directory 53.Ar newroot 54and exec's 55.Ar command , 56if supplied, or an interactive copy of your shell. 57.Pp 58If the 59.Fl u , 60.Fl g 61or 62.Fl G 63options are given, the user, group and group list of the process are 64set to these values after the chroot has taken place. See 65.Xr setgid 2 , 66.Xr setgroups 2 , 67.Xr setuid 2 , 68.Xr getgrnam 3 69and 70.Xr getpwnam 3 . 71.Pp 72Note, 73.Ar command 74or the shell are run as your real-user-id. 75.Sh ENVIRONMENT 76The following environment variable is referenced by 77.Nm "" : 78.Bl -tag -width SHELL 79.It Ev SHELL 80If set, 81the string specified by 82.Ev SHELL 83is interpreted as the name of 84the shell to exec. 85If the variable 86.Ev SHELL 87is not set, 88.Pa /bin/sh 89is used. 90.El 91.Sh SEE ALSO 92.Xr chdir 2 , 93.Xr chroot 2 , 94.Xr environ 7 95.Sh HISTORY 96The 97.Nm 98utility first appeared in 99.Bx 4.4 . 100.Sh SECURITY CONSIDERATIONS 101.Nm 102should never be installed setuid root, as it would then be possible 103to exploit the program to gain root privileges. 104