'\" 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.
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.TH chroot 2 "20 Jan 2003" "SunOS 5.11" "System Calls"
.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
.mk
.na
\fB\fBEACCES\fR\fR
.ad
.RS 16n
.rt  
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
.mk
.na
\fB\fBEBADF\fR\fR
.ad
.RS 16n
.rt  
The descriptor is not valid.
.RE

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

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

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

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

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

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is no longer active.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

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

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

.SH SEE ALSO
.sp
.LP
\fBchroot\fR(1M), \fBchdir\fR(2), \fBprivileges\fR(5)
.SH WARNINGS
.sp
.LP
The only use of \fBfchroot()\fR that is appropriate is to change back to the
system root.