1 /* Change the ownership and mode bits of a directory.
3 Copyright (C) 2006, 2007 Free Software Foundation, Inc.
5 This program is free software: you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 3 of the License, or
8 (at your option) any later version.
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with this program. If not, see <http://www.gnu.org/licenses/>. */
18 /* Written by Paul Eggert. */
22 #include "dirchownmod.h"
25 #include <sys/types.h>
30 #include "stat-macros.h"
33 # define HAVE_FCHMOD 0
35 # define fchmod(fd, mode) (-1)
38 /* Change the ownership and mode bits of a directory. If FD is
39 nonnegative, it should be a file descriptor associated with the
40 directory; close it before returning. DIR is the name of the
43 If MKDIR_MODE is not (mode_t) -1, mkdir (DIR, MKDIR_MODE) has just
44 been executed successfully with umask zero, so DIR should be a
45 directory (not a symbolic link).
47 First, set the file's owner to OWNER and group to GROUP, but leave
48 the owner alone if OWNER is (uid_t) -1, and similarly for GROUP.
50 Then, set the file's mode bits to MODE, except preserve any of the
51 bits that correspond to zero bits in MODE_BITS. In other words,
52 MODE_BITS is a mask that specifies which of the file's mode bits
53 should be set or cleared. MODE should be a subset of MODE_BITS,
54 which in turn should be a subset of CHMOD_MODE_BITS.
56 This implementation assumes the current umask is zero.
58 Return 0 if successful, -1 (setting errno) otherwise. Unsuccessful
59 calls may do the chown but not the chmod. */
62 dirchownmod (int fd, char const *dir, mode_t mkdir_mode,
63 uid_t owner, gid_t group,
64 mode_t mode, mode_t mode_bits)
67 int result = (fd < 0 ? stat (dir, &st) : fstat (fd, &st));
71 mode_t dir_mode = st.st_mode;
73 /* Check whether DIR is a directory. If FD is nonnegative, this
74 check avoids changing the ownership and mode bits of the
75 wrong file in many cases. This doesn't fix all the race
76 conditions, but it is better than nothing. */
77 if (! S_ISDIR (dir_mode))
84 /* If at least one of the S_IXUGO bits are set, chown might
85 clear the S_ISUID and S_SGID bits. Keep track of any
86 file mode bits whose values are indeterminate due to this
88 mode_t indeterminate = 0;
90 /* On some systems, chown clears S_ISUID and S_ISGID, so do
91 chown before chmod. On older System V hosts, ordinary
92 users can give their files away via chown; don't worry
93 about that here, since users shouldn't do that. */
95 if ((owner != (uid_t) -1 && owner != st.st_uid)
96 || (group != (gid_t) -1 && group != st.st_gid))
99 ? fchown (fd, owner, group)
100 : mkdir_mode != (mode_t) -1
101 ? lchown (dir, owner, group)
102 : chown (dir, owner, group));
104 /* Either the user cares about an indeterminate bit and
105 it'll be set properly by chmod below, or the user
106 doesn't care and it's OK to use the bit's pre-chown
107 value. So there's no need to re-stat DIR here. */
109 if (result == 0 && (dir_mode & S_IXUGO))
110 indeterminate = dir_mode & (S_ISUID | S_ISGID);
113 /* If the file mode bits might not be right, use chmod to
114 change them. Don't change bits the user doesn't care
116 if (result == 0 && (((dir_mode ^ mode) | indeterminate) & mode_bits))
119 mode | (dir_mode & CHMOD_MODE_BITS & ~mode_bits);
120 result = (HAVE_FCHMOD && 0 <= fd
121 ? fchmod (fd, chmod_mode)
122 : mkdir_mode != (mode_t) -1
123 ? lchmod (dir, chmod_mode)
124 : chmod (dir, chmod_mode));