[unix-history] / lib / libc / sys / chroot.2

.\" Copyright (c) 1983, 1991 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. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"	This product includes software developed by the University of
.\"	California, Berkeley and its contributors.
.\" 4. 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	6.5 (Berkeley) 3/10/91
.\"
.Dd March 10, 1991
.Dt CHROOT 2
.Os BSD 4.2
.Sh NAME
.Nm chroot
.Nd change root directory
.Sh SYNOPSIS
.Fd #include <unistd.h>
.Ft int
.Fn chroot "const char *dirname"
.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
It should be noted that
.Fn chroot
has no effect on the process's current directory.
.Pp
This call is restricted to the super-user.
.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 [ENOTDIR]
.It Bq Er ENOTDIR
A component of the path name is not a directory.
.It Bq Er EINVAL
The pathname contains a character with the high-order bit set.
.It Bq Er ENAMETOOLONG
A component of a pathname exceeded 255 characters,
or an entire path name exceeded 1023 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 Path
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.
.El
.Sh SEE ALSO
.Xr chdir 2
.Sh HISTORY
The
.Nm
function call appeared in
.Bx 4.2 .
Commit	Line	Data
15637ed4 RG	1	.\" Copyright (c) 1983, 1991 Regents of the University of California.
	2	.\" All rights reserved.
	3	.\"
	4	.\" Redistribution and use in source and binary forms, with or without
	5	.\" modification, are permitted provided that the following conditions
	6	.\" are met:
	7	.\" 1. Redistributions of source code must retain the above copyright
	8	.\" notice, this list of conditions and the following disclaimer.
	9	.\" 2. Redistributions in binary form must reproduce the above copyright
	10	.\" notice, this list of conditions and the following disclaimer in the
	11	.\" documentation and/or other materials provided with the distribution.
	12	.\" 3. All advertising materials mentioning features or use of this software
	13	.\" must display the following acknowledgement:
	14	.\" This product includes software developed by the University of
	15	.\" California, Berkeley and its contributors.
	16	.\" 4. Neither the name of the University nor the names of its contributors
	17	.\" may be used to endorse or promote products derived from this software
	18	.\" without specific prior written permission.
	19	.\"
	20	.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	21	.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	22	.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	23	.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	24	.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	25	.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	26	.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	27	.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	28	.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	29	.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	30	.\" SUCH DAMAGE.
	31	.\"
	32	.\" @(#)chroot.2 6.5 (Berkeley) 3/10/91
	33	.\"
	34	.Dd March 10, 1991
	35	.Dt CHROOT 2
	36	.Os BSD 4.2
	37	.Sh NAME
	38	.Nm chroot
	39	.Nd change root directory
	40	.Sh SYNOPSIS
	41	.Fd #include <unistd.h>
	42	.Ft int
	43	.Fn chroot "const char *dirname"
	44	.Sh DESCRIPTION
	45	.Fa Dirname
	46	is the address of the pathname of a directory, terminated by an ASCII NUL.
	47	.Fn Chroot
	48	causes
	49	.Fa dirname
	50	to become the root directory,
	51	that is, the starting point for path searches of pathnames
	52	beginning with
	53	.Ql / .
	54	.Pp
	55	In order for a directory to become the root directory
	56	a process must have execute (search) access for that directory.
	57	.Pp
	58	It should be noted that
	59	.Fn chroot
	60	has no effect on the process's current directory.
	61	.Pp
	62	This call is restricted to the super-user.
	63	.Sh RETURN VALUES
	64	Upon successful completion, a value of 0 is returned. Otherwise,
65	a value of -1 is returned and
66	.Va errno
67	is set to indicate an error.
68	.Sh ERRORS
69	.Fn Chroot
70	will fail and the root directory will be unchanged if:
71	.Bl -tag -width [ENOTDIR]
72	.It Bq Er ENOTDIR
73	A component of the path name is not a directory.
74	.It Bq Er EINVAL
75	The pathname contains a character with the high-order bit set.
76	.It Bq Er ENAMETOOLONG
77	A component of a pathname exceeded 255 characters,
78	or an entire path name exceeded 1023 characters.
79	.It Bq Er ENOENT
80	The named directory does not exist.
81	.It Bq Er EACCES
82	Search permission is denied for any component of the path name.
83	.It Bq Er ELOOP
84	Too many symbolic links were encountered in translating the pathname.
85	.It Bq Er EFAULT
86	.Fa Path
87	points outside the process's allocated address space.
88	.It Bq Er EIO
89	An I/O error occurred while reading from or writing to the file system.
90	.El
91	.Sh SEE ALSO
92	.Xr chdir 2
93	.Sh HISTORY
94	The
95	.Nm
96	function call appeared in
97	.Bx 4.2 .