| /* 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; |
| } |