rm-rf.c revision b26fa1a2fbcfee7d03b0c8fd15ec3aa64ae70b9f
/***
This file is part of systemd.
Copyright 2015 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 <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <stdbool.h>
#include <stddef.h>
#include <sys/stat.h>
#include <sys/statfs.h>
#include <unistd.h>
#include "btrfs-util.h"
#include "fd-util.h"
#include "log.h"
#include "macro.h"
#include "mount-util.h"
#include "path-util.h"
#include "rm-rf.h"
#include "stat-util.h"
#include "string-util.h"
int rm_rf_children(int fd, RemoveFlags flags, struct stat *root_dev) {
_cleanup_closedir_ DIR *d = NULL;
int ret = 0, r;
assert(fd >= 0);
/* This returns the first error we run into, but nevertheless
* tries to go on. This closes the passed fd. */
if (!(flags & REMOVE_PHYSICAL)) {
r = fd_is_temporary_fs(fd);
if (r < 0) {
safe_close(fd);
return r;
}
if (!r) {
/* We refuse to clean physical file systems
* with this call, unless explicitly
* requested. This is extra paranoia just to
* be sure we never ever remove non-state
* data */
log_error("Attempted to remove disk file system, and we can't allow that.");
safe_close(fd);
return -EPERM;
}
}
d = fdopendir(fd);
if (!d) {
safe_close(fd);
return errno == ENOENT ? 0 : -errno;
}
for (;;) {
struct dirent *de;
bool is_dir;
struct stat st;
errno = 0;
de = readdir(d);
if (!de) {
if (errno > 0 && ret == 0)
ret = -errno;
return ret;
}
if (streq(de->d_name, ".") || streq(de->d_name, ".."))
continue;
if (de->d_type == DT_UNKNOWN ||
(de->d_type == DT_DIR && (root_dev || (flags & REMOVE_SUBVOLUME)))) {
if (fstatat(fd, de->d_name, &st, AT_SYMLINK_NOFOLLOW) < 0) {
if (ret == 0 && errno != ENOENT)
ret = -errno;
continue;
}
is_dir = S_ISDIR(st.st_mode);
} else
is_dir = de->d_type == DT_DIR;
if (is_dir) {
int subdir_fd;
/* if root_dev is set, remove subdirectories only if device is same */
if (root_dev && st.st_dev != root_dev->st_dev)
continue;
subdir_fd = openat(fd, de->d_name, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|O_NOFOLLOW|O_NOATIME);
if (subdir_fd < 0) {
if (ret == 0 && errno != ENOENT)
ret = -errno;
continue;
}
/* Stop at mount points */
r = fd_is_mount_point(fd, de->d_name, 0);
if (r < 0) {
if (ret == 0 && r != -ENOENT)
ret = r;
safe_close(subdir_fd);
continue;
}
if (r) {
safe_close(subdir_fd);
continue;
}
if ((flags & REMOVE_SUBVOLUME) && st.st_ino == 256) {
/* This could be a subvolume, try to remove it */
r = btrfs_subvol_remove_fd(fd, de->d_name, BTRFS_REMOVE_RECURSIVE|BTRFS_REMOVE_QUOTA);
if (r < 0) {
if (r != -ENOTTY && r != -EINVAL) {
if (ret == 0)
ret = r;
safe_close(subdir_fd);
continue;
}
/* ENOTTY, then it wasn't a
* btrfs subvolume, continue
* below. */
} else {
/* It was a subvolume, continue. */
safe_close(subdir_fd);
continue;
}
}
/* We pass REMOVE_PHYSICAL here, to avoid
* doing the fstatfs() to check the file
* system type again for each directory */
r = rm_rf_children(subdir_fd, flags | REMOVE_PHYSICAL, root_dev);
if (r < 0 && ret == 0)
ret = r;
if (unlinkat(fd, de->d_name, AT_REMOVEDIR) < 0) {
if (ret == 0 && errno != ENOENT)
ret = -errno;
}
} else if (!(flags & REMOVE_ONLY_DIRECTORIES)) {
if (unlinkat(fd, de->d_name, 0) < 0) {
if (ret == 0 && errno != ENOENT)
ret = -errno;
}
}
}
}
int rm_rf(const char *path, RemoveFlags flags) {
int fd, r;
struct statfs s;
assert(path);
/* We refuse to clean the root file system with this
* call. This is extra paranoia to never cause a really
* seriously broken system. */
if (path_equal(path, "/")) {
log_error("Attempted to remove entire root file system, and we can't allow that.");
return -EPERM;
}
if ((flags & (REMOVE_SUBVOLUME|REMOVE_ROOT|REMOVE_PHYSICAL)) == (REMOVE_SUBVOLUME|REMOVE_ROOT|REMOVE_PHYSICAL)) {
/* Try to remove as subvolume first */
r = btrfs_subvol_remove(path, BTRFS_REMOVE_RECURSIVE|BTRFS_REMOVE_QUOTA);
if (r >= 0)
return r;
if (r != -ENOTTY && r != -EINVAL && r != -ENOTDIR)
return r;
/* Not btrfs or not a subvolume */
}
fd = open(path, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|O_NOFOLLOW|O_NOATIME);
if (fd < 0) {
if (errno != ENOTDIR && errno != ELOOP)
return -errno;
if (!(flags & REMOVE_PHYSICAL)) {
if (statfs(path, &s) < 0)
return -errno;
if (!is_temporary_fs(&s)) {
log_error("Attempted to remove disk file system, and we can't allow that.");
return -EPERM;
}
}
if ((flags & REMOVE_ROOT) && !(flags & REMOVE_ONLY_DIRECTORIES))
if (unlink(path) < 0 && errno != ENOENT)
return -errno;
return 0;
}
r = rm_rf_children(fd, flags, NULL);
if (flags & REMOVE_ROOT) {
if (rmdir(path) < 0) {
if (r == 0 && errno != ENOENT)
r = -errno;
}
}
return r;
}