153 lines
4.7 KiB
Groff
153 lines
4.7 KiB
Groff
.\" $NetBSD: chroot.2,v 1.21 2003/08/07 16:43:56 agc Exp $
|
|
.\"
|
|
.\" Copyright (c) 1983, 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.
|
|
.\"
|
|
.\" @(#)chroot.2 8.1 (Berkeley) 6/4/93
|
|
.\"
|
|
.Dd April 18, 2001
|
|
.Dt CHROOT 2
|
|
.Os
|
|
.Sh NAME
|
|
.Nm chroot
|
|
.Nd change root directory
|
|
.Sh LIBRARY
|
|
.Lb libc
|
|
.Sh SYNOPSIS
|
|
.In unistd.h
|
|
.Ft int
|
|
.Fn chroot "const char *dirname"
|
|
.Ft int
|
|
.Fn fchroot "int fd"
|
|
.Sh DESCRIPTION
|
|
.Fa dirname
|
|
is the address of the pathname of a directory, terminated by an ASCII NUL.
|
|
.Fn chroot
|
|
causes
|
|
.Fa dirname
|
|
to become the root directory,
|
|
that is, the starting point for path searches of pathnames
|
|
beginning with
|
|
.Ql / .
|
|
.Pp
|
|
In order for a directory to become the root directory
|
|
a process must have execute (search) access for that directory.
|
|
.Pp
|
|
If the current working directory is not at or under the new root
|
|
directory, it is silently set to the new root directory.
|
|
It should be noted that, on most other systems,
|
|
.Fn chroot
|
|
has no effect on the process's current directory.
|
|
.Pp
|
|
This call is restricted to the super-user.
|
|
.Pp
|
|
The
|
|
.Fn fchroot
|
|
function performs the same operation on an open directory file
|
|
known by the file descriptor
|
|
.Fa fd .
|
|
.Sh RETURN VALUES
|
|
Upon successful completion, a value of 0 is returned.
|
|
Otherwise, a value of -1 is returned and
|
|
.Va errno
|
|
is set to indicate an error.
|
|
.Sh ERRORS
|
|
.Fn chroot
|
|
will fail and the root directory will be unchanged if:
|
|
.Bl -tag -width Er
|
|
.It Bq Er ENOTDIR
|
|
A component of the path name is not a directory.
|
|
.It Bq Er ENAMETOOLONG
|
|
A component of a pathname exceeded
|
|
.Dv {NAME_MAX}
|
|
characters, or an entire path name exceeded
|
|
.Dv {PATH_MAX}
|
|
characters.
|
|
.It Bq Er ENOENT
|
|
The named directory does not exist.
|
|
.It Bq Er EACCES
|
|
Search permission is denied for any component of the path name.
|
|
.It Bq Er ELOOP
|
|
Too many symbolic links were encountered in translating the pathname.
|
|
.It Bq Er EFAULT
|
|
.Fa dirname
|
|
points outside the process's allocated address space.
|
|
.It Bq Er EIO
|
|
An I/O error occurred while reading from or writing to the file system.
|
|
.It Bq Er EPERM
|
|
The effective user ID of the calling process is not the super-user.
|
|
.El
|
|
.Pp
|
|
.Fn fchroot
|
|
will fail and the root directory will be unchanged if:
|
|
.Bl -tag -width Er
|
|
.It Bq Er EACCES
|
|
Search permission is denied for the directory referenced
|
|
by the file descriptor.
|
|
.It Bq Er EBADF
|
|
The argument
|
|
.Fa fd
|
|
is not a valid file descriptor.
|
|
.It Bq Er EIO
|
|
An I/O error occurred while reading from or writing to the file system.
|
|
.It Bq Er ENOTDIR
|
|
The argument
|
|
.Fa fd
|
|
does not reference a directory.
|
|
.It Bq Er EPERM
|
|
The effective user ID of the calling process is not the super-user.
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr chdir 2
|
|
.Sh STANDARDS
|
|
The
|
|
.Fn chroot
|
|
function conforms to
|
|
.St -xsh5 ,
|
|
with the restriction that the calling process' working directory must be at
|
|
or under the new root directory.
|
|
Otherwise, the working directory is silently set to the new root directory;
|
|
this is an extension to the standard.
|
|
.Pp
|
|
.Fn chroot
|
|
was declared a legacy interface, and subsequently removed in
|
|
.St -p1003.1-2001 .
|
|
.Sh HISTORY
|
|
The
|
|
.Fn chroot
|
|
function call appeared in
|
|
.Bx 4.2 .
|
|
Working directory handling was changed in
|
|
.Nx 1.4
|
|
to prevent one way a process could use a second
|
|
.Fn chroot
|
|
call to a different directory to "escape" from the restricted subtree.
|
|
The
|
|
.Fn fchroot
|
|
function appeared in
|
|
.Nx 1.4 .
|