Edit
kc3-lang/gnulib/lib/dirchownmod.c
Jim Meyering
- lib/dirchownmod.c
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/* Change the ownership and mode bits of a directory. Copyright (C) 2006-2010 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 <http://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; }