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-rw-r--r--src/basic/rm-rf.c265
1 files changed, 265 insertions, 0 deletions
diff --git a/src/basic/rm-rf.c b/src/basic/rm-rf.c
new file mode 100644
index 0000000..b0d682f
--- /dev/null
+++ b/src/basic/rm-rf.c
@@ -0,0 +1,265 @@
+/* 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;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-29 16:16:04 +0000