| /* 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" |
| |
| /* We treat tmpfs/ramfs + cgroupfs as non-physical file sytems. cgroupfs is similar to tmpfs in a way after |
| * all: we can create arbitrary directory hierarchies in it, and hence can also use rm_rf() on it to remove |
| * those again. */ |
| static bool is_physical_fs(const struct statfs *sfs) { |
| return !is_temporary_fs(sfs) && !is_cgroup_fs(sfs); |
| } |
| |
| static int patch_dirfd_mode( |
| int dfd, |
| mode_t *ret_old_mode) { |
| |
| struct stat st; |
| |
| assert(dfd >= 0); |
| assert(ret_old_mode); |
| |
| 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; |
| |
| *ret_old_mode = st.st_mode; |
| return 0; |
| } |
| |
| int unlinkat_harder(int dfd, const char *filename, int unlink_flags, RemoveFlags remove_flags) { |
| mode_t old_mode; |
| 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; |
| |
| r = patch_dirfd_mode(dfd, &old_mode); |
| if (r < 0) |
| return r; |
| |
| if (unlinkat(dfd, filename, unlink_flags) < 0) { |
| r = -errno; |
| /* Try to restore the original access mode if this didn't work */ |
| (void) fchmod(dfd, old_mode); |
| return r; |
| } |
| |
| if (FLAGS_SET(remove_flags, REMOVE_CHMOD_RESTORE) && fchmod(dfd, old_mode) < 0) |
| return -errno; |
| |
| /* If this worked, we won't reset the old mode by default, since we'll need it for other entries too, |
| * and we should destroy the whole thing */ |
| return 0; |
| } |
| |
| int fstatat_harder(int dfd, |
| const char *filename, |
| struct stat *ret, |
| int fstatat_flags, |
| RemoveFlags remove_flags) { |
| |
| mode_t old_mode; |
| int r; |
| |
| /* Like unlink_harder() but does the same for fstatat() */ |
| |
| if (fstatat(dfd, filename, ret, fstatat_flags) >= 0) |
| return 0; |
| if (errno != EACCES || !FLAGS_SET(remove_flags, REMOVE_CHMOD)) |
| return -errno; |
| |
| r = patch_dirfd_mode(dfd, &old_mode); |
| if (r < 0) |
| return r; |
| |
| if (fstatat(dfd, filename, ret, fstatat_flags) < 0) { |
| r = -errno; |
| (void) fchmod(dfd, old_mode); |
| return r; |
| } |
| |
| if (FLAGS_SET(remove_flags, REMOVE_CHMOD_RESTORE) && fchmod(dfd, old_mode) < 0) |
| return -errno; |
| |
| return 0; |
| } |
| |
| static int rm_rf_inner_child( |
| int fd, |
| const char *fname, |
| int is_dir, |
| RemoveFlags flags, |
| const struct stat *root_dev, |
| bool allow_recursion) { |
| |
| struct stat st; |
| int r, q = 0; |
| |
| assert(fd >= 0); |
| assert(fname); |
| |
| if (is_dir < 0 || |
| root_dev || |
| (is_dir > 0 && (root_dev || (flags & REMOVE_SUBVOLUME)))) { |
| |
| r = fstatat_harder(fd, fname, &st, AT_SYMLINK_NOFOLLOW, flags); |
| if (r < 0) |
| return r; |
| |
| is_dir = S_ISDIR(st.st_mode); |
| } |
| |
| if (is_dir) { |
| /* If root_dev is set, remove subdirectories only if device is same */ |
| if (root_dev && st.st_dev != root_dev->st_dev) |
| return 0; |
| |
| /* Stop at mount points */ |
| r = fd_is_mount_point(fd, fname, 0); |
| if (r < 0) |
| return r; |
| if (r > 0) |
| return 0; |
| |
| if ((flags & REMOVE_SUBVOLUME) && btrfs_might_be_subvol(&st)) { |
| /* This could be a subvolume, try to remove it */ |
| |
| r = btrfs_subvol_remove_fd(fd, fname, BTRFS_REMOVE_RECURSIVE|BTRFS_REMOVE_QUOTA); |
| if (r < 0) { |
| if (!IN_SET(r, -ENOTTY, -EINVAL)) |
| return r; |
| |
| /* ENOTTY, then it wasn't a btrfs subvolume, continue below. */ |
| } else |
| /* It was a subvolume, done. */ |
| return 1; |
| } |
| |
| if (!allow_recursion) |
| return -EISDIR; |
| |
| int subdir_fd = openat(fd, fname, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|O_NOFOLLOW|O_NOATIME); |
| if (subdir_fd < 0) |
| return -errno; |
| |
| /* We pass REMOVE_PHYSICAL here, to avoid doing the fstatfs() to check the file system type |
| * again for each directory */ |
| q = rm_rf_children(subdir_fd, flags | REMOVE_PHYSICAL, root_dev); |
| |
| } else if (flags & REMOVE_ONLY_DIRECTORIES) |
| return 0; |
| |
| r = unlinkat_harder(fd, fname, is_dir ? AT_REMOVEDIR : 0, flags); |
| if (r < 0) |
| return r; |
| if (q < 0) |
| return q; |
| return 1; |
| } |
| |
| typedef struct TodoEntry { |
| DIR *dir; /* A directory that we were operating on. */ |
| char *dirname; /* The filename of that directory itself. */ |
| } TodoEntry; |
| |
| static void free_todo_entries(TodoEntry **todos) { |
| for (TodoEntry *x = *todos; x && x->dir; x++) { |
| closedir(x->dir); |
| free(x->dirname); |
| } |
| |
| freep(todos); |
| } |
| |
| int rm_rf_children( |
| int fd, |
| RemoveFlags flags, |
| const struct stat *root_dev) { |
| |
| _cleanup_(free_todo_entries) TodoEntry *todos = NULL; |
| size_t n_todo = 0; |
| _cleanup_free_ char *dirname = NULL; /* Set when we are recursing and want to delete ourselves */ |
| int ret = 0, r; |
| |
| /* Return the first error we run into, but nevertheless try to go on. |
| * The passed fd is closed in all cases, including on failure. */ |
| |
| for (;;) { /* This loop corresponds to the directory nesting level. */ |
| _cleanup_closedir_ DIR *d = NULL; |
| |
| if (n_todo > 0) { |
| /* We know that we are in recursion here, because n_todo is set. |
| * We need to remove the inner directory we were operating on. */ |
| assert(dirname); |
| r = unlinkat_harder(dirfd(todos[n_todo-1].dir), dirname, AT_REMOVEDIR, flags); |
| if (r < 0 && r != -ENOENT && ret == 0) |
| ret = r; |
| dirname = mfree(dirname); |
| |
| /* And now let's back out one level up */ |
| n_todo --; |
| d = TAKE_PTR(todos[n_todo].dir); |
| dirname = TAKE_PTR(todos[n_todo].dirname); |
| |
| assert(d); |
| fd = dirfd(d); /* Retrieve the file descriptor from the DIR object */ |
| assert(fd >= 0); |
| } else { |
| next_fd: |
| assert(fd >= 0); |
| d = fdopendir(fd); |
| if (!d) { |
| safe_close(fd); |
| return -errno; |
| } |
| fd = dirfd(d); /* We donated the fd to fdopendir(). Let's make sure we sure we have |
| * the right descriptor even if it were to internally invalidate the |
| * one we passed. */ |
| |
| if (!(flags & REMOVE_PHYSICAL)) { |
| struct statfs sfs; |
| |
| if (fstatfs(fd, &sfs) < 0) |
| 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); |
| return log_error_errno(SYNTHETIC_ERRNO(EPERM), |
| "Attempted to remove disk file system under \"%s\", and we can't allow that.", |
| strna(path)); |
| } |
| } |
| } |
| |
| struct dirent *de; |
| FOREACH_DIRENT_ALL(de, d, return -errno) { |
| int is_dir; |
| |
| if (dot_or_dot_dot(de->d_name)) |
| continue; |
| |
| is_dir = de->d_type == DT_UNKNOWN ? -1 : de->d_type == DT_DIR; |
| |
| r = rm_rf_inner_child(fd, de->d_name, is_dir, flags, root_dev, false); |
| if (r == -EISDIR) { |
| /* Push the current working state onto the todo list */ |
| |
| if (!GREEDY_REALLOC0(todos, n_todo + 2)) |
| return log_oom(); |
| |
| _cleanup_free_ char *newdirname = strdup(de->d_name); |
| if (!newdirname) |
| return log_oom(); |
| |
| int newfd = openat(fd, de->d_name, |
| O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|O_NOFOLLOW|O_NOATIME); |
| if (newfd >= 0) { |
| todos[n_todo++] = (TodoEntry) { TAKE_PTR(d), TAKE_PTR(dirname) }; |
| fd = newfd; |
| dirname = TAKE_PTR(newdirname); |
| |
| goto next_fd; |
| |
| } else if (errno != -ENOENT && ret == 0) |
| ret = -errno; |
| |
| } else if (r < 0 && r != -ENOENT && ret == 0) |
| ret = r; |
| } |
| |
| if (FLAGS_SET(flags, REMOVE_SYNCFS) && syncfs(fd) < 0 && ret >= 0) |
| ret = -errno; |
| |
| if (n_todo == 0) |
| break; |
| } |
| |
| return ret; |
| } |
| |
| int rm_rf(const char *path, RemoveFlags flags) { |
| int fd, r, q = 0; |
| |
| 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) { |
| /* We have a dir */ |
| r = rm_rf_children(fd, flags, NULL); |
| |
| if (FLAGS_SET(flags, REMOVE_ROOT) && rmdir(path) < 0) |
| q = -errno; |
| } else { |
| 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) || !FLAGS_SET(flags, REMOVE_ROOT)) |
| return 0; |
| |
| if (!FLAGS_SET(flags, REMOVE_PHYSICAL)) { |
| struct statfs s; |
| |
| 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); |
| } |
| |
| r = 0; |
| if (unlink(path) < 0) |
| q = -errno; |
| } |
| |
| if (r < 0) |
| return r; |
| if (q < 0 && (q != -ENOENT || !FLAGS_SET(flags, REMOVE_MISSING_OK))) |
| return q; |
| return 0; |
| } |
| |
| int rm_rf_child(int fd, const char *name, RemoveFlags flags) { |
| |
| /* Removes one specific child of the specified directory */ |
| |
| if (fd < 0) |
| return -EBADF; |
| |
| if (!filename_is_valid(name)) |
| return -EINVAL; |
| |
| if ((flags & (REMOVE_ROOT|REMOVE_MISSING_OK)) != 0) /* Doesn't really make sense here, we are not supposed to remove 'fd' anyway */ |
| return -EINVAL; |
| |
| if (FLAGS_SET(flags, REMOVE_ONLY_DIRECTORIES|REMOVE_SUBVOLUME)) |
| return -EINVAL; |
| |
| return rm_rf_inner_child(fd, name, -1, flags, NULL, true); |
| } |
