/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ /*** This file is part of systemd. Copyright 2015 Lennart Poettering systemd is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. systemd is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with systemd; If not, see <http://www.gnu.org/licenses/>. ***/ #include <dirent.h> #include <errno.h> #include <fcntl.h> #include <stdbool.h> #include <stddef.h> #include <sys/stat.h> #include <sys/statfs.h> #include <unistd.h> #include "btrfs-util.h" #include "fd-util.h" #include "log.h" #include "macro.h" #include "mount-util.h" #include "path-util.h" #include "rm-rf.h" #include "stat-util.h" #include "string-util.h" int rm_rf_children(int fd, RemoveFlags flags, struct stat *root_dev) { _cleanup_closedir_ DIR *d = NULL; int ret = 0, r; 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 = fd_is_temporary_fs(fd); if (r < 0) { safe_close(fd); return r; } if (!r) { /* 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 */ log_error("Attempted to remove disk file system, and we can't allow that."); safe_close(fd); return -EPERM; } } d = fdopendir(fd); if (!d) { safe_close(fd); return errno == ENOENT ? 0 : -errno; } for (;;) { struct dirent *de; bool is_dir; struct stat st; errno = 0; de = readdir(d); if (!de) { if (errno != 0 && ret == 0) ret = -errno; return ret; } if (streq(de->d_name, ".") || streq(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 (r != -ENOTTY && r != -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; } } } } 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(path, "/")) { log_error("Attempted to remove entire root file system, and we can't allow that."); return -EPERM; } if ((flags & (REMOVE_SUBVOLUME|REMOVE_ROOT|REMOVE_PHYSICAL)) == (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 (r != -ENOTTY && r != -EINVAL && r != -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 (errno != ENOTDIR && errno != ELOOP) return -errno; if (!(flags & REMOVE_PHYSICAL)) { if (statfs(path, &s) < 0) return -errno; if (!is_temporary_fs(&s)) { log_error("Attempted to remove disk file system, and we can't allow that."); return -EPERM; } } 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; }