/* SPDX-License-Identifier: LGPL-2.1+ */ #include #include #include #include #include #include #include #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); } 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. */ 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) { 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 (!IN_SET(r, -ENOTTY, -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; } } } 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 (!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 (!IN_SET(errno, ENOTDIR, ELOOP)) return -errno; if (!(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 ((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; }