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1 | .\" $NetBSD: chroot.2,v 1.7 1995/02/27 12:32:12 cgd Exp $ | |
2 | .\" | |
3 | .\" Copyright (c) 1983, 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 | .\" @(#)chroot.2 8.1 (Berkeley) 6/4/93 | |
35 | .\" | |
36 | .Dd June 4, 1993 | |
37 | .Dt CHROOT 2 | |
38 | .Os BSD 4.2 | |
39 | .Sh NAME | |
40 | .Nm chroot | |
41 | .Nd change root directory | |
42 | .Sh SYNOPSIS | |
43 | .Fd #include <unistd.h> | |
44 | .Ft int | |
45 | .Fn chroot "const char *dirname" | |
46 | .Sh DESCRIPTION | |
47 | .Fa Dirname | |
48 | is the address of the pathname of a directory, terminated by an ASCII NUL. | |
49 | .Fn chroot | |
50 | causes | |
51 | .Fa dirname | |
52 | to become the root directory, | |
53 | that is, the starting point for path searches of pathnames | |
54 | beginning with | |
55 | .Ql / . | |
56 | .Pp | |
57 | In order for a directory to become the root directory | |
58 | a process must have execute (search) access for that directory. | |
59 | .Pp | |
60 | If the program is not currently running with an altered root directory, | |
61 | it should be noted that | |
62 | .Fn chroot | |
63 | has no effect on the process's current directory. | |
64 | .Pp | |
65 | If the program is already running with an altered root directory, the | |
66 | process's current directory is changed to the same new root directory. | |
67 | This prevents the current directory from being further up the directory | |
68 | tree than the altered root directory. | |
69 | .Pp | |
70 | This call is restricted to the super-user. | |
71 | .Sh RETURN VALUES | |
72 | Upon successful completion, a value of 0 is returned. Otherwise, | |
73 | a value of -1 is returned and | |
74 | .Va errno | |
75 | is set to indicate an error. | |
76 | .Sh ERRORS | |
77 | .Fn chroot | |
78 | will fail and the root directory will be unchanged if: | |
79 | .Bl -tag -width Er | |
80 | .It Bq Er ENOTDIR | |
81 | A component of the path name is not a directory. | |
82 | .It Bq Er ENAMETOOLONG | |
83 | A component of a pathname exceeded | |
84 | .Dv {NAME_MAX} | |
85 | characters, or an entire path name exceeded | |
86 | .Dv {PATH_MAX} | |
87 | characters. | |
88 | .It Bq Er ENOENT | |
89 | The named directory does not exist. | |
90 | .It Bq Er EACCES | |
91 | Search permission is denied for any component of the path name. | |
92 | .It Bq Er ELOOP | |
93 | Too many symbolic links were encountered in translating the pathname. | |
94 | .It Bq Er EFAULT | |
95 | .Fa Path | |
96 | points outside the process's allocated address space. | |
97 | .It Bq Er EIO | |
98 | An I/O error occurred while reading from or writing to the file system. | |
99 | .El | |
100 | .Sh SEE ALSO | |
101 | .Xr chdir 2 | |
102 | .Sh WARNINGS | |
103 | There are ways for a root process to escape from the chroot jail. | |
104 | .Sh HISTORY | |
105 | The | |
106 | .Fn chroot | |
107 | function call appeared in | |
108 | .Bx 4.2 . |