diff options
Diffstat (limited to 'src/libsystemd-basic/src/rm-rf.c')
| -rw-r--r-- | src/libsystemd-basic/src/rm-rf.c | 242 |
1 files changed, 242 insertions, 0 deletions
diff --git a/src/libsystemd-basic/src/rm-rf.c b/src/libsystemd-basic/src/rm-rf.c new file mode 100644 index 0000000000..b6410d52d5 --- /dev/null +++ b/src/libsystemd-basic/src/rm-rf.c @@ -0,0 +1,242 @@ +/*** + 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 "systemd-basic/btrfs-util.h" +#include "systemd-basic/cgroup-util.h" +#include "systemd-basic/fd-util.h" +#include "systemd-basic/log.h" +#include "systemd-basic/macro.h" +#include "systemd-basic/mount-util.h" +#include "systemd-basic/path-util.h" +#include "systemd-basic/rm-rf.h" +#include "systemd-basic/stat-util.h" +#include "systemd-basic/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; + 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 */ + + 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_physical_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; +} |