Commit | Line | Data |
---|---|---|
d149e2aa KM |
1 | .\" Copyright (c) 1980 Regents of the University of California. |
2 | .\" All rights reserved. The Berkeley software License Agreement | |
3 | .\" specifies the terms and conditions for redistribution. | |
4 | .\" | |
86ce3f09 | 5 | .\" @(#)chmod.2 6.3 (Berkeley) %G% |
d149e2aa | 6 | .\" |
3efa6125 | 7 | .TH CHMOD 2 "" |
d149e2aa KM |
8 | .UC 4 |
9 | .SH NAME | |
10 | chmod \- change mode of file | |
11 | .SH SYNOPSIS | |
12 | .nf | |
7656e522 KM |
13 | .ft B |
14 | chmod(path, mode) | |
15 | char *path; | |
16 | int mode; | |
17 | .PP | |
18 | .ft B | |
19 | fchmod(fd, mode) | |
20 | int fd, mode; | |
d149e2aa KM |
21 | .fi |
22 | .SH DESCRIPTION | |
23 | The file whose name | |
7656e522 KM |
24 | is given by \fIpath\fP |
25 | or referenced by the descriptor | |
26 | .I fd | |
d149e2aa KM |
27 | has its mode changed to |
28 | .IR mode . | |
29 | Modes are constructed by | |
7656e522 | 30 | .IR or 'ing |
d149e2aa KM |
31 | together some |
32 | combination of the following: | |
33 | .PP | |
34 | .RS | |
35 | 04000 set user ID on execution | |
36 | 02000 set group ID on execution | |
37 | 01000 save text image after execution | |
38 | 00400 read by owner | |
39 | 00200 write by owner | |
40 | 00100 execute (search on directory) by owner | |
41 | 00070 read, write, execute (search) by group | |
42 | 00007 read, write, execute (search) by others | |
43 | .RE | |
44 | .PP | |
45 | If an executable file is set up for sharing (this is the default) | |
46 | then mode 1000 prevents the system from | |
47 | abandoning the swap-space image of the program-text portion | |
48 | of the file when its last user | |
49 | terminates. | |
7656e522 | 50 | Ability to set this bit is restricted to the super-user. |
d149e2aa KM |
51 | .PP |
52 | Only the owner of a file (or the super-user) may change the mode. | |
d149e2aa | 53 | .PP |
7656e522 KM |
54 | Writing or changing the owner of a file |
55 | turns off the set-user-id and set-group-id bits. | |
d149e2aa | 56 | This makes the system somewhat more secure |
7656e522 KM |
57 | by protecting set-user-id (set-group-id) files |
58 | from remaining set-user-id (set-group-id) if they are modified, | |
d149e2aa | 59 | at the expense of a degree of compatibility. |
7656e522 KM |
60 | .SH "RETURN VALUE |
61 | Upon successful completion, a value of 0 is returned. | |
62 | Otherwise, a value of \-1 is returned and | |
63 | .I errno | |
64 | is set to indicate the error. | |
65 | .SH "ERRORS | |
66 | .I Chmod | |
67 | will fail and the file mode will be unchanged if: | |
68 | .TP 15 | |
7656e522 KM |
69 | [ENOTDIR] |
70 | A component of the path prefix is not a directory. | |
71 | .TP 15 | |
b5984ffe KM |
72 | [EINVAL] |
73 | The pathname contains a character with the high-order bit set. | |
74 | .TP 15 | |
75 | [ENAMETOOLONG] | |
76 | A component of a pathname exceeded 255 characters, | |
77 | or an entire path name exceeded 1023 characters. | |
7656e522 KM |
78 | .TP 15 |
79 | [ENOENT] | |
80 | The named file does not exist. | |
81 | .TP 15 | |
82 | [EACCES] | |
b5984ffe KM |
83 | Search permission is denied for a component of the path prefix. |
84 | .TP 15 | |
85 | [ELOOP] | |
86 | Too many symbolic links were encountered in translating the pathname. | |
7656e522 KM |
87 | .TP 15 |
88 | [EPERM] | |
89 | The effective user ID does not match the owner of the file and | |
90 | the effective user ID is not the super-user. | |
91 | .TP 15 | |
92 | [EROFS] | |
93 | The named file resides on a read-only file system. | |
94 | .TP 15 | |
95 | [EFAULT] | |
96 | .I Path | |
97 | points outside the process's allocated address space. | |
fd690c8b KM |
98 | .TP 15 |
99 | [EIO] | |
100 | An I/O error occurred while reading from or writing to the file system. | |
7656e522 KM |
101 | .PP |
102 | .I Fchmod | |
103 | will fail if: | |
104 | .TP 15 | |
105 | [EBADF] | |
106 | The descriptor is not valid. | |
107 | .TP 15 | |
108 | [EINVAL] | |
109 | .I Fd | |
110 | refers to a socket, not to a file. | |
111 | .TP 15 | |
112 | [EROFS] | |
113 | The file resides on a read-only file system. | |
fd690c8b KM |
114 | .TP 15 |
115 | [EIO] | |
116 | An I/O error occurred while reading from or writing to the file system. | |
d149e2aa | 117 | .SH "SEE ALSO" |
7656e522 | 118 | open(2), chown(2) |