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/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include <errno.h>
#include <fcntl.h>
#include <stdbool.h>
#include <stddef.h>
#include <unistd.h>
#include "alloc-util.h"
#include "btrfs-util.h"
#include "cgroup-util.h"
#include "dirent-util.h"
#include "fd-util.h"
#include "log.h"
#include "macro.h"
#include "mountpoint-util.h"
#include "path-util.h"
#include "rm-rf.h"
#include "stat-util.h"
#include "string-util.h"
static bool is_physical_fs(const struct statfs *sfs) {
return !is_temporary_fs(sfs) && !is_cgroup_fs(sfs);
}
static int unlinkat_harder(
int dfd,
const char *filename,
int unlink_flags,
RemoveFlags remove_flags) {
struct stat st;
int r;
/* Like unlinkat(), but tries harder: if we get EACCESS we'll try to set the r/w/x bits on the
* directory. This is useful if we run unprivileged and have some files where the w bit is
* missing. */
if (unlinkat(dfd, filename, unlink_flags) >= 0)
return 0;
if (errno != EACCES || !FLAGS_SET(remove_flags, REMOVE_CHMOD))
return -errno;
if (fstat(dfd, &st) < 0)
return -errno;
if (!S_ISDIR(st.st_mode))
return -ENOTDIR;
if (FLAGS_SET(st.st_mode, 0700)) /* Already set? */
return -EACCES; /* original error */
if (st.st_uid != geteuid()) /* this only works if the UID matches ours */
return -EACCES;
if (fchmod(dfd, (st.st_mode | 0700) & 07777) < 0)
return -errno;
if (unlinkat(dfd, filename, unlink_flags) < 0) {
r = -errno;
/* Try to restore the original access mode if this didn't work */
(void) fchmod(dfd, st.st_mode & 07777);
return r;
}
return 0;
}
int rm_rf_children(int fd, RemoveFlags flags, struct stat *root_dev) {
_cleanup_closedir_ DIR *d = NULL;
struct dirent *de;
int ret = 0, r;
struct statfs sfs;
assert(fd >= 0);
/* This returns the first error we run into, but nevertheless tries to go on. This closes the passed
* fd, in all cases, including on failure.. */
if (!(flags & REMOVE_PHYSICAL)) {
r = fstatfs(fd, &sfs);
if (r < 0) {
safe_close(fd);
return -errno;
}
if (is_physical_fs(&sfs)) {
/* 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. */
_cleanup_free_ char *path = NULL;
(void) fd_get_path(fd, &path);
log_error("Attempted to remove disk file system under \"%s\", and we can't allow that.",
strna(path));
safe_close(fd);
return -EPERM;
}
}
d = fdopendir(fd);
if (!d) {
safe_close(fd);
return errno == ENOENT ? 0 : -errno;
}
FOREACH_DIRENT_ALL(de, d, return -errno) {
bool is_dir;
struct stat st;
if (dot_or_dot_dot(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) {
_cleanup_close_ int subdir_fd = -1;
/* 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;
continue;
}
if (r > 0)
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 (!IN_SET(r, -ENOTTY, -EINVAL)) {
if (ret == 0)
ret = r;
continue;
}
/* ENOTTY, then it wasn't a btrfs subvolume, continue below. */
} else
/* It was a subvolume, continue. */
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(TAKE_FD(subdir_fd), flags | REMOVE_PHYSICAL, root_dev);
if (r < 0 && ret == 0)
ret = r;
r = unlinkat_harder(fd, de->d_name, AT_REMOVEDIR, flags);
if (r < 0 && r != -ENOENT && ret == 0)
ret = r;
} else if (!(flags & REMOVE_ONLY_DIRECTORIES)) {
r = unlinkat_harder(fd, de->d_name, 0, flags);
if (r < 0 && r != -ENOENT && ret == 0)
ret = r;
}
}
return ret;
}
int rm_rf(const char *path, RemoveFlags flags) {
int fd, r;
struct statfs s;
assert(path);
/* For now, don't support dropping subvols when also only dropping directories, since we can't do
* this race-freely. */
if (FLAGS_SET(flags, REMOVE_ONLY_DIRECTORIES|REMOVE_SUBVOLUME))
return -EINVAL;
/* 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_or_files_same(path, "/", AT_SYMLINK_NOFOLLOW))
return log_error_errno(SYNTHETIC_ERRNO(EPERM),
"Attempted to remove entire root file system (\"%s\"), and we can't allow that.",
path);
if (FLAGS_SET(flags, 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 (FLAGS_SET(flags, REMOVE_MISSING_OK) && r == -ENOENT)
return 0;
if (!IN_SET(r, -ENOTTY, -EINVAL, -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 (FLAGS_SET(flags, REMOVE_MISSING_OK) && errno == ENOENT)
return 0;
if (!IN_SET(errno, ENOTDIR, ELOOP))
return -errno;
if (FLAGS_SET(flags, REMOVE_ONLY_DIRECTORIES))
return 0;
if (FLAGS_SET(flags, REMOVE_ROOT)) {
if (!FLAGS_SET(flags, REMOVE_PHYSICAL)) {
if (statfs(path, &s) < 0)
return -errno;
if (is_physical_fs(&s))
return log_error_errno(SYNTHETIC_ERRNO(EPERM),
"Attempted to remove files from a disk file system under \"%s\", refusing.",
path);
}
if (unlink(path) < 0) {
if (FLAGS_SET(flags, REMOVE_MISSING_OK) && errno == ENOENT)
return 0;
return -errno;
}
}
return 0;
}
r = rm_rf_children(fd, flags, NULL);
if (FLAGS_SET(flags, REMOVE_ROOT) &&
rmdir(path) < 0 &&
r >= 0 &&
(!FLAGS_SET(flags, REMOVE_MISSING_OK) || errno != ENOENT))
r = -errno;
return r;
}
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