diff options
Diffstat (limited to '')
| -rw-r--r-- | src/basic/rm-rf.c | 220 |
1 files changed, 220 insertions, 0 deletions
diff --git a/src/basic/rm-rf.c b/src/basic/rm-rf.c new file mode 100644 index 0000000..0c957c9 --- /dev/null +++ b/src/basic/rm-rf.c @@ -0,0 +1,220 @@ +/* SPDX-License-Identifier: LGPL-2.1+ */ + +#include <errno.h> +#include <fcntl.h> +#include <stdbool.h> +#include <stddef.h> +#include <sys/stat.h> +#include <sys/statfs.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); +} + +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); + + /* 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; +} |