'\" te
.\"  Copyright 1989 AT&T.  Copyright (c) 2003, Sun Microsystems, Inc.  All Rights Reserved
.\" The contents of this file are subject to the terms of the Common Development and Distribution License (the "License").  You may not use this file except in compliance with the License.
.\" You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE or http://www.opensolaris.org/os/licensing.  See the License for the specific language governing permissions and limitations under the License.
.\" When distributing Covered Code, include this CDDL HEADER in each file and include the License file at usr/src/OPENSOLARIS.LICENSE.  If applicable, add the following below this CDDL HEADER, with the fields enclosed by brackets "[]" replaced with your own identifying information: Portions Copyright [yyyy] [name of copyright owner]
.TH CHROOT 2 "Jan 20, 2003"
.SH NAME
chroot, fchroot \- change root directory
.SH SYNOPSIS
.LP
.nf
#include <unistd.h>

\fBint\fR \fBchroot\fR(\fBconst char *\fR\fIpath\fR);
.fi

.LP
.nf
\fBint\fR \fBfchroot\fR(\fBint\fR \fIfildes\fR);
.fi

.SH DESCRIPTION
.sp
.LP
The \fBchroot()\fR and  \fBfchroot()\fR functions cause a directory to become
the root directory, the starting point for path searches for path names
beginning with \fB/\fR (slash). The user's working directory is unaffected by
the \fBchroot()\fR and \fBfchroot()\fR functions.
.sp
.LP
The \fIpath\fR argument points to a path name naming a directory. The
\fIfildes\fR argument to \fBfchroot()\fR is the open file descriptor of the
directory which is to become the root.
.sp
.LP
The privilege {\fBPRIV_PROC_CHROOT\fR} must be asserted in the effective set of
the process to change the root directory. While it is always possible to change
to the system root using the \fBfchroot()\fR function, it is not guaranteed to
succeed in any other case, even if \fIfildes\fR is valid in all respects.
.sp
.LP
The ".\|." entry in the root directory is interpreted to mean the root
directory itself. Therefore, ".\|." cannot be used to access files outside the
subtree rooted at the root directory. Instead, \fBfchroot()\fR can be used to
reset the root to a directory that was opened before the root directory was
changed.
.SH RETURN VALUES
.sp
.LP
Upon successful completion, \fB0\fR is returned. Otherwise, \fB\(mi1\fR is
returned, the root directory remains unchanged, and \fBerrno\fR is set to
indicate the error.
.SH ERRORS
.sp
.LP
The \fBchroot()\fR function will fail if:
.sp
.ne 2
.na
\fB\fBEACCES\fR\fR
.ad
.RS 16n
Search permission is denied for a component of the path prefix of
\fIdirname\fR, or search permission is denied for the directory referred to by
\fIdirname\fR.
.RE

.sp
.ne 2
.na
\fB\fBEBADF\fR\fR
.ad
.RS 16n
The descriptor is not valid.
.RE

.sp
.ne 2
.na
\fB\fBEFAULT\fR\fR
.ad
.RS 16n
The \fIpath\fR argument points to an illegal address.
.RE

.sp
.ne 2
.na
\fB\fBEINVAL\fR\fR
.ad
.RS 16n
The \fBfchroot()\fR function attempted to change to a directory the is not the
system root and external circumstances do not allow this.
.RE

.sp
.ne 2
.na
\fB\fBEINTR\fR\fR
.ad
.RS 16n
A signal was caught during the execution of the \fBchroot()\fR function.
.RE

.sp
.ne 2
.na
\fB\fBEIO\fR\fR
.ad
.RS 16n
An I/O error occurred while reading from or writing to the file system.
.RE

.sp
.ne 2
.na
\fB\fBELOOP\fR\fR
.ad
.RS 16n
Too many symbolic links were encountered in translating \fIpath\fR.
.RE

.sp
.ne 2
.na
\fB\fBENAMETOOLONG\fR\fR
.ad
.RS 16n
The length of the \fIpath\fR argument exceeds \fBPATH_MAX\fR, or the length of
a \fIpath\fR component exceeds \fB\fR\fBNAME_MAX\fR while \fB_POSIX_NO_TRUNC\fR
is in effect.
.RE

.sp
.ne 2
.na
\fB\fBENOENT\fR\fR
.ad
.RS 16n
The named directory does not exist or is a null pathname.
.RE

.sp
.ne 2
.na
\fB\fBENOLINK\fR\fR
.ad
.RS 16n
The \fIpath\fR argument points to a remote machine and the link to that machine
is no longer active.
.RE

.sp
.ne 2
.na
\fB\fBENOTDIR\fR\fR
.ad
.RS 16n
Any component of the path name is not a directory.
.RE

.sp
.ne 2
.na
\fB\fBEPERM\fR\fR
.ad
.RS 16n
The {\fBPRIV_PROC_CHROOT\fR} privilege is not asserted in the effective set of
the calling process.
.RE

.SH SEE ALSO
.sp
.LP
.BR chdir (2),
.BR privileges (7),
.BR chroot (8)
.SH WARNINGS
.sp
.LP
The only use of \fBfchroot()\fR that is appropriate is to change back to the
system root.