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/* SPDX-License-Identifier: LGPL-2.1+ */
/***
This file is part of systemd.
Copyright 2017 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include "user-util.h"
#include "macro.h"
#include "fd-util.h"
#include "dirent-util.h"
#include "chown-recursive.h"
static int chown_one(int fd, const char *name, const struct stat *st, uid_t uid, gid_t gid) {
int r;
assert(fd >= 0);
assert(st);
if ((!uid_is_valid(uid) || st->st_uid == uid) &&
(!gid_is_valid(gid) || st->st_gid == gid))
return 0;
if (name)
r = fchownat(fd, name, uid, gid, AT_SYMLINK_NOFOLLOW);
else
r = fchown(fd, uid, gid);
if (r < 0)
return -errno;
/* The linux kernel alters the mode in some cases of chown(). Let's undo this. */
if (name) {
if (!S_ISLNK(st->st_mode))
r = fchmodat(fd, name, st->st_mode, 0);
else /* There's currently no AT_SYMLINK_NOFOLLOW for fchmodat() */
r = 0;
} else
r = fchmod(fd, st->st_mode);
if (r < 0)
return -errno;
return 1;
}
static int chown_recursive_internal(int fd, const struct stat *st, uid_t uid, gid_t gid) {
bool changed = false;
int r;
assert(fd >= 0);
assert(st);
if (S_ISDIR(st->st_mode)) {
_cleanup_closedir_ DIR *d = NULL;
struct dirent *de;
d = fdopendir(fd);
if (!d) {
r = -errno;
goto finish;
}
fd = -1;
FOREACH_DIRENT_ALL(de, d, r = -errno; goto finish) {
struct stat fst;
if (dot_or_dot_dot(de->d_name))
continue;
if (fstatat(dirfd(d), de->d_name, &fst, AT_SYMLINK_NOFOLLOW) < 0) {
r = -errno;
goto finish;
}
if (S_ISDIR(fst.st_mode)) {
int subdir_fd;
subdir_fd = openat(dirfd(d), de->d_name, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|O_NOFOLLOW|O_NOATIME);
if (subdir_fd < 0) {
r = -errno;
goto finish;
}
r = chown_recursive_internal(subdir_fd, &fst, uid, gid);
if (r < 0)
goto finish;
if (r > 0)
changed = true;
} else {
r = chown_one(dirfd(d), de->d_name, &fst, uid, gid);
if (r < 0)
goto finish;
if (r > 0)
changed = true;
}
}
r = chown_one(dirfd(d), NULL, st, uid, gid);
} else
r = chown_one(fd, NULL, st, uid, gid);
if (r < 0)
goto finish;
r = r > 0 || changed;
finish:
safe_close(fd);
return r;
}
int path_chown_recursive(const char *path, uid_t uid, gid_t gid) {
_cleanup_close_ int fd = -1;
struct stat st;
int r;
fd = open(path, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|O_NOFOLLOW|O_NOATIME);
if (fd < 0)
return -errno;
if (!uid_is_valid(uid) && !gid_is_valid(gid))
return 0; /* nothing to do */
if (fstat(fd, &st) < 0)
return -errno;
/* Let's take a shortcut: if the top-level directory is properly owned, we don't descend into the whole tree,
* under the assumption that all is OK anyway. */
if ((!uid_is_valid(uid) || st.st_uid == uid) &&
(!gid_is_valid(gid) || st.st_gid == gid))
return 0;
r = chown_recursive_internal(fd, &st, uid, gid);
fd = -1; /* we donated the fd to the call, regardless if it succeeded or failed */
return r;
}
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