| /* Change the ownership and mode bits of a directory. |
| |
| Copyright (C) 2006-2020 Free Software Foundation, Inc. |
| |
| This program is free software: you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 3 of the License, or |
| (at your option) any later version. |
| |
| This program is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with this program. If not, see <https://www.gnu.org/licenses/>. */ |
| |
| /* Written by Paul Eggert. */ |
| |
| #include <config.h> |
| |
| #include "dirchownmod.h" |
| |
| #include <errno.h> |
| #include <sys/types.h> |
| #include <sys/stat.h> |
| #include <unistd.h> |
| |
| #include "stat-macros.h" |
| |
| #ifndef HAVE_FCHMOD |
| # define HAVE_FCHMOD 0 |
| # undef fchmod |
| # define fchmod(fd, mode) (-1) |
| #endif |
| |
| /* Change the ownership and mode bits of a directory. If FD is |
| nonnegative, it should be a file descriptor associated with the |
| directory; close it before returning. DIR is the name of the |
| directory. |
| |
| If MKDIR_MODE is not (mode_t) -1, mkdir (DIR, MKDIR_MODE) has just |
| been executed successfully with umask zero, so DIR should be a |
| directory (not a symbolic link). |
| |
| First, set the file's owner to OWNER and group to GROUP, but leave |
| the owner alone if OWNER is (uid_t) -1, and similarly for GROUP. |
| |
| Then, set the file's mode bits to MODE, except preserve any of the |
| bits that correspond to zero bits in MODE_BITS. In other words, |
| MODE_BITS is a mask that specifies which of the file's mode bits |
| should be set or cleared. MODE should be a subset of MODE_BITS, |
| which in turn should be a subset of CHMOD_MODE_BITS. |
| |
| This implementation assumes the current umask is zero. |
| |
| Return 0 if successful, -1 (setting errno) otherwise. Unsuccessful |
| calls may do the chown but not the chmod. */ |
| |
| int |
| dirchownmod (int fd, char const *dir, mode_t mkdir_mode, |
| uid_t owner, gid_t group, |
| mode_t mode, mode_t mode_bits) |
| { |
| struct stat st; |
| int result = (fd < 0 ? stat (dir, &st) : fstat (fd, &st)); |
| |
| if (result == 0) |
| { |
| mode_t dir_mode = st.st_mode; |
| |
| /* Check whether DIR is a directory. If FD is nonnegative, this |
| check avoids changing the ownership and mode bits of the |
| wrong file in many cases. This doesn't fix all the race |
| conditions, but it is better than nothing. */ |
| if (! S_ISDIR (dir_mode)) |
| { |
| errno = ENOTDIR; |
| result = -1; |
| } |
| else |
| { |
| /* If at least one of the S_IXUGO bits are set, chown might |
| clear the S_ISUID and S_SGID bits. Keep track of any |
| file mode bits whose values are indeterminate due to this |
| issue. */ |
| mode_t indeterminate = 0; |
| |
| /* On some systems, chown clears S_ISUID and S_ISGID, so do |
| chown before chmod. On older System V hosts, ordinary |
| users can give their files away via chown; don't worry |
| about that here, since users shouldn't do that. */ |
| |
| if ((owner != (uid_t) -1 && owner != st.st_uid) |
| || (group != (gid_t) -1 && group != st.st_gid)) |
| { |
| result = (0 <= fd |
| ? fchown (fd, owner, group) |
| : mkdir_mode != (mode_t) -1 |
| ? lchown (dir, owner, group) |
| : chown (dir, owner, group)); |
| |
| /* Either the user cares about an indeterminate bit and |
| it'll be set properly by chmod below, or the user |
| doesn't care and it's OK to use the bit's pre-chown |
| value. So there's no need to re-stat DIR here. */ |
| |
| if (result == 0 && (dir_mode & S_IXUGO)) |
| indeterminate = dir_mode & (S_ISUID | S_ISGID); |
| } |
| |
| /* If the file mode bits might not be right, use chmod to |
| change them. Don't change bits the user doesn't care |
| about. */ |
| if (result == 0 && (((dir_mode ^ mode) | indeterminate) & mode_bits)) |
| { |
| mode_t chmod_mode = |
| mode | (dir_mode & CHMOD_MODE_BITS & ~mode_bits); |
| result = (HAVE_FCHMOD && 0 <= fd |
| ? fchmod (fd, chmod_mode) |
| : mkdir_mode != (mode_t) -1 |
| ? lchmod (dir, chmod_mode) |
| : chmod (dir, chmod_mode)); |
| } |
| } |
| } |
| |
| if (0 <= fd) |
| { |
| if (result == 0) |
| result = close (fd); |
| else |
| { |
| int e = errno; |
| close (fd); |
| errno = e; |
| } |
| } |
| |
| return result; |
| } |