| /* SPDX-License-Identifier: LGPL-2.1+ */ |
| /*** |
| Copyright © 2010 ProFUSION embedded systems |
| ***/ |
| |
| #include <errno.h> |
| #include <fcntl.h> |
| #include <linux/loop.h> |
| #include <string.h> |
| #include <sys/mount.h> |
| #include <sys/swap.h> |
| #include <sys/stat.h> |
| #include <sys/types.h> |
| #include <unistd.h> |
| |
| /* This needs to be after sys/mount.h :( */ |
| #include <libmount.h> |
| |
| #include "sd-device.h" |
| |
| #include "alloc-util.h" |
| #include "blockdev-util.h" |
| #include "def.h" |
| #include "device-util.h" |
| #include "escape.h" |
| #include "fd-util.h" |
| #include "fstab-util.h" |
| #include "linux-3.13/dm-ioctl.h" |
| #include "mount-setup.h" |
| #include "mount-util.h" |
| #include "mountpoint-util.h" |
| #include "path-util.h" |
| #include "process-util.h" |
| #include "signal-util.h" |
| #include "string-util.h" |
| #include "strv.h" |
| #include "umount.h" |
| #include "util.h" |
| #include "virt.h" |
| |
| DEFINE_TRIVIAL_CLEANUP_FUNC(struct libmnt_table*, mnt_free_table); |
| DEFINE_TRIVIAL_CLEANUP_FUNC(struct libmnt_iter*, mnt_free_iter); |
| |
| static void mount_point_free(MountPoint **head, MountPoint *m) { |
| assert(head); |
| assert(m); |
| |
| LIST_REMOVE(mount_point, *head, m); |
| |
| free(m->path); |
| free(m->remount_options); |
| free(m); |
| } |
| |
| void mount_points_list_free(MountPoint **head) { |
| assert(head); |
| |
| while (*head) |
| mount_point_free(head, *head); |
| } |
| |
| int mount_points_list_get(const char *mountinfo, MountPoint **head) { |
| _cleanup_(mnt_free_tablep) struct libmnt_table *t = NULL; |
| _cleanup_(mnt_free_iterp) struct libmnt_iter *i = NULL; |
| int r; |
| |
| assert(head); |
| |
| t = mnt_new_table(); |
| i = mnt_new_iter(MNT_ITER_FORWARD); |
| if (!t || !i) |
| return log_oom(); |
| |
| r = mnt_table_parse_mtab(t, mountinfo); |
| if (r < 0) |
| return log_error_errno(r, "Failed to parse %s: %m", mountinfo); |
| |
| for (;;) { |
| struct libmnt_fs *fs; |
| const char *path, *fstype; |
| _cleanup_free_ char *options = NULL; |
| _cleanup_free_ char *p = NULL; |
| unsigned long remount_flags = 0u; |
| _cleanup_free_ char *remount_options = NULL; |
| bool try_remount_ro; |
| MountPoint *m; |
| |
| r = mnt_table_next_fs(t, i, &fs); |
| if (r == 1) |
| break; |
| if (r < 0) |
| return log_error_errno(r, "Failed to get next entry from %s: %m", mountinfo); |
| |
| path = mnt_fs_get_target(fs); |
| if (!path) |
| continue; |
| |
| if (cunescape(path, UNESCAPE_RELAX, &p) < 0) |
| return log_oom(); |
| |
| fstype = mnt_fs_get_fstype(fs); |
| |
| /* Combine the generic VFS options with the FS-specific |
| * options. Duplicates are not a problem here, because the only |
| * options that should come up twice are typically ro/rw, which |
| * are turned into MS_RDONLY or the invertion of it. |
| * |
| * Even if there are duplicates later in mount_option_mangle() |
| * it shouldn't hurt anyways as they override each other. |
| */ |
| if (!strextend_with_separator(&options, ",", |
| mnt_fs_get_vfs_options(fs), |
| NULL)) |
| return log_oom(); |
| if (!strextend_with_separator(&options, ",", |
| mnt_fs_get_fs_options(fs), |
| NULL)) |
| return log_oom(); |
| |
| /* Ignore mount points we can't unmount because they |
| * are API or because we are keeping them open (like |
| * /dev/console). Also, ignore all mounts below API |
| * file systems, since they are likely virtual too, |
| * and hence not worth spending time on. Also, in |
| * unprivileged containers we might lack the rights to |
| * unmount these things, hence don't bother. */ |
| if (mount_point_is_api(p) || |
| mount_point_ignore(p) || |
| PATH_STARTSWITH_SET(p, "/dev", "/sys", "/proc")) |
| continue; |
| |
| /* If we are in a container, don't attempt to |
| * read-only mount anything as that brings no real |
| * benefits, but might confuse the host, as we remount |
| * the superblock here, not the bind mount. |
| * |
| * If the filesystem is a network fs, also skip the |
| * remount. It brings no value (we cannot leave |
| * a "dirty fs") and could hang if the network is down. |
| * Note that umount2() is more careful and will not |
| * hang because of the network being down. */ |
| try_remount_ro = detect_container() <= 0 && |
| !fstype_is_network(fstype) && |
| !fstype_is_api_vfs(fstype) && |
| !fstype_is_ro(fstype) && |
| !fstab_test_yes_no_option(options, "ro\0rw\0"); |
| |
| if (try_remount_ro) { |
| /* mount(2) states that mount flags and options need to be exactly the same |
| * as they were when the filesystem was mounted, except for the desired |
| * changes. So we reconstruct both here and adjust them for the later |
| * remount call too. */ |
| |
| r = mnt_fs_get_propagation(fs, &remount_flags); |
| if (r < 0) { |
| log_warning_errno(r, "mnt_fs_get_propagation() failed for %s, ignoring: %m", path); |
| continue; |
| } |
| |
| r = mount_option_mangle(options, remount_flags, &remount_flags, &remount_options); |
| if (r < 0) { |
| log_warning_errno(r, "mount_option_mangle failed for %s, ignoring: %m", path); |
| continue; |
| } |
| |
| /* MS_BIND is special. If it is provided it will only make the mount-point |
| * read-only. If left out, the super block itself is remounted, which we want. */ |
| remount_flags = (remount_flags|MS_REMOUNT|MS_RDONLY) & ~MS_BIND; |
| } |
| |
| m = new0(MountPoint, 1); |
| if (!m) |
| return log_oom(); |
| |
| free_and_replace(m->path, p); |
| free_and_replace(m->remount_options, remount_options); |
| m->remount_flags = remount_flags; |
| m->try_remount_ro = try_remount_ro; |
| |
| LIST_PREPEND(mount_point, *head, m); |
| } |
| |
| return 0; |
| } |
| |
| int swap_list_get(const char *swaps, MountPoint **head) { |
| _cleanup_(mnt_free_tablep) struct libmnt_table *t = NULL; |
| _cleanup_(mnt_free_iterp) struct libmnt_iter *i = NULL; |
| int r; |
| |
| assert(head); |
| |
| t = mnt_new_table(); |
| i = mnt_new_iter(MNT_ITER_FORWARD); |
| if (!t || !i) |
| return log_oom(); |
| |
| r = mnt_table_parse_swaps(t, swaps); |
| if (r < 0) |
| return log_error_errno(r, "Failed to parse %s: %m", swaps); |
| |
| for (;;) { |
| struct libmnt_fs *fs; |
| |
| MountPoint *swap; |
| const char *source; |
| _cleanup_free_ char *d = NULL; |
| |
| r = mnt_table_next_fs(t, i, &fs); |
| if (r == 1) |
| break; |
| if (r < 0) |
| return log_error_errno(r, "Failed to get next entry from %s: %m", swaps); |
| |
| source = mnt_fs_get_source(fs); |
| if (!source) |
| continue; |
| |
| r = cunescape(source, UNESCAPE_RELAX, &d); |
| if (r < 0) |
| return r; |
| |
| swap = new0(MountPoint, 1); |
| if (!swap) |
| return -ENOMEM; |
| |
| free_and_replace(swap->path, d); |
| LIST_PREPEND(mount_point, *head, swap); |
| } |
| |
| return 0; |
| } |
| |
| static int loopback_list_get(MountPoint **head) { |
| _cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *e = NULL; |
| sd_device *d; |
| int r; |
| |
| assert(head); |
| |
| r = sd_device_enumerator_new(&e); |
| if (r < 0) |
| return r; |
| |
| r = sd_device_enumerator_allow_uninitialized(e); |
| if (r < 0) |
| return r; |
| |
| r = sd_device_enumerator_add_match_subsystem(e, "block", true); |
| if (r < 0) |
| return r; |
| |
| r = sd_device_enumerator_add_match_sysname(e, "loop*"); |
| if (r < 0) |
| return r; |
| |
| r = sd_device_enumerator_add_match_sysattr(e, "loop/backing_file", NULL, true); |
| if (r < 0) |
| return r; |
| |
| FOREACH_DEVICE(e, d) { |
| _cleanup_free_ char *p = NULL; |
| const char *dn; |
| MountPoint *lb; |
| |
| if (sd_device_get_devname(d, &dn) < 0) |
| continue; |
| |
| p = strdup(dn); |
| if (!p) |
| return -ENOMEM; |
| |
| lb = new(MountPoint, 1); |
| if (!lb) |
| return -ENOMEM; |
| |
| *lb = (MountPoint) { |
| .path = TAKE_PTR(p), |
| }; |
| |
| LIST_PREPEND(mount_point, *head, lb); |
| } |
| |
| return 0; |
| } |
| |
| static int dm_list_get(MountPoint **head) { |
| _cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *e = NULL; |
| sd_device *d; |
| int r; |
| |
| assert(head); |
| |
| r = sd_device_enumerator_new(&e); |
| if (r < 0) |
| return r; |
| |
| r = sd_device_enumerator_allow_uninitialized(e); |
| if (r < 0) |
| return r; |
| |
| r = sd_device_enumerator_add_match_subsystem(e, "block", true); |
| if (r < 0) |
| return r; |
| |
| r = sd_device_enumerator_add_match_sysname(e, "dm-*"); |
| if (r < 0) |
| return r; |
| |
| FOREACH_DEVICE(e, d) { |
| _cleanup_free_ char *p = NULL; |
| const char *dn; |
| MountPoint *m; |
| dev_t devnum; |
| |
| if (sd_device_get_devnum(d, &devnum) < 0 || |
| sd_device_get_devname(d, &dn) < 0) |
| continue; |
| |
| p = strdup(dn); |
| if (!p) |
| return -ENOMEM; |
| |
| m = new(MountPoint, 1); |
| if (!m) |
| return -ENOMEM; |
| |
| *m = (MountPoint) { |
| .path = TAKE_PTR(p), |
| .devnum = devnum, |
| }; |
| |
| LIST_PREPEND(mount_point, *head, m); |
| } |
| |
| return 0; |
| } |
| |
| static int delete_loopback(const char *device) { |
| _cleanup_close_ int fd = -1; |
| int r; |
| |
| assert(device); |
| |
| fd = open(device, O_RDONLY|O_CLOEXEC); |
| if (fd < 0) |
| return errno == ENOENT ? 0 : -errno; |
| |
| r = ioctl(fd, LOOP_CLR_FD, 0); |
| if (r >= 0) |
| return 1; |
| |
| /* ENXIO: not bound, so no error */ |
| if (errno == ENXIO) |
| return 0; |
| |
| return -errno; |
| } |
| |
| static int delete_dm(dev_t devnum) { |
| |
| struct dm_ioctl dm = { |
| .version = { |
| DM_VERSION_MAJOR, |
| DM_VERSION_MINOR, |
| DM_VERSION_PATCHLEVEL |
| }, |
| .data_size = sizeof(dm), |
| .dev = devnum, |
| }; |
| |
| _cleanup_close_ int fd = -1; |
| |
| assert(major(devnum) != 0); |
| |
| fd = open("/dev/mapper/control", O_RDWR|O_CLOEXEC); |
| if (fd < 0) |
| return -errno; |
| |
| if (ioctl(fd, DM_DEV_REMOVE, &dm) < 0) |
| return -errno; |
| |
| return 0; |
| } |
| |
| static bool nonunmountable_path(const char *path) { |
| return path_equal(path, "/") |
| #if ! HAVE_SPLIT_USR |
| || path_equal(path, "/usr") |
| #endif |
| || path_startswith(path, "/run/initramfs"); |
| } |
| |
| static int remount_with_timeout(MountPoint *m, int umount_log_level) { |
| pid_t pid; |
| int r; |
| |
| BLOCK_SIGNALS(SIGCHLD); |
| |
| assert(m); |
| |
| /* Due to the possiblity of a remount operation hanging, we |
| * fork a child process and set a timeout. If the timeout |
| * lapses, the assumption is that that particular remount |
| * failed. */ |
| r = safe_fork("(sd-remount)", FORK_RESET_SIGNALS|FORK_CLOSE_ALL_FDS|FORK_LOG|FORK_REOPEN_LOG, &pid); |
| if (r < 0) |
| return r; |
| if (r == 0) { |
| log_info("Remounting '%s' read-only in with options '%s'.", m->path, m->remount_options); |
| |
| /* Start the mount operation here in the child */ |
| r = mount(NULL, m->path, NULL, m->remount_flags, m->remount_options); |
| if (r < 0) |
| log_full_errno(umount_log_level, errno, "Failed to remount '%s' read-only: %m", m->path); |
| |
| _exit(r < 0 ? EXIT_FAILURE : EXIT_SUCCESS); |
| } |
| |
| r = wait_for_terminate_with_timeout(pid, DEFAULT_TIMEOUT_USEC); |
| if (r == -ETIMEDOUT) { |
| log_error_errno(r, "Remounting '%s' timed out, issuing SIGKILL to PID " PID_FMT ".", m->path, pid); |
| (void) kill(pid, SIGKILL); |
| } else if (r == -EPROTO) |
| log_debug_errno(r, "Remounting '%s' failed abnormally, child process " PID_FMT " aborted or exited non-zero.", m->path, pid); |
| else if (r < 0) |
| log_error_errno(r, "Remounting '%s' failed unexpectedly, couldn't wait for child process " PID_FMT ": %m", m->path, pid); |
| |
| return r; |
| } |
| |
| static int umount_with_timeout(MountPoint *m, int umount_log_level) { |
| pid_t pid; |
| int r; |
| |
| BLOCK_SIGNALS(SIGCHLD); |
| |
| assert(m); |
| |
| /* Due to the possiblity of a umount operation hanging, we |
| * fork a child process and set a timeout. If the timeout |
| * lapses, the assumption is that that particular umount |
| * failed. */ |
| r = safe_fork("(sd-umount)", FORK_RESET_SIGNALS|FORK_CLOSE_ALL_FDS|FORK_LOG|FORK_REOPEN_LOG, &pid); |
| if (r < 0) |
| return r; |
| if (r == 0) { |
| log_info("Unmounting '%s'.", m->path); |
| |
| /* Start the mount operation here in the child Using MNT_FORCE |
| * causes some filesystems (e.g. FUSE and NFS and other network |
| * filesystems) to abort any pending requests and return -EIO |
| * rather than blocking indefinitely. If the filesysten is |
| * "busy", this may allow processes to die, thus making the |
| * filesystem less busy so the unmount might succeed (rather |
| * then return EBUSY).*/ |
| r = umount2(m->path, MNT_FORCE); |
| if (r < 0) |
| log_full_errno(umount_log_level, errno, "Failed to unmount %s: %m", m->path); |
| |
| _exit(r < 0 ? EXIT_FAILURE : EXIT_SUCCESS); |
| } |
| |
| r = wait_for_terminate_with_timeout(pid, DEFAULT_TIMEOUT_USEC); |
| if (r == -ETIMEDOUT) { |
| log_error_errno(r, "Unmounting '%s' timed out, issuing SIGKILL to PID " PID_FMT ".", m->path, pid); |
| (void) kill(pid, SIGKILL); |
| } else if (r == -EPROTO) |
| log_debug_errno(r, "Unmounting '%s' failed abnormally, child process " PID_FMT " aborted or exited non-zero.", m->path, pid); |
| else if (r < 0) |
| log_error_errno(r, "Unmounting '%s' failed unexpectedly, couldn't wait for child process " PID_FMT ": %m", m->path, pid); |
| |
| return r; |
| } |
| |
| /* This includes remounting readonly, which changes the kernel mount options. |
| * Therefore the list passed to this function is invalidated, and should not be reused. */ |
| static int mount_points_list_umount(MountPoint **head, bool *changed, int umount_log_level) { |
| MountPoint *m; |
| int n_failed = 0; |
| |
| assert(head); |
| assert(changed); |
| |
| LIST_FOREACH(mount_point, m, *head) { |
| if (m->try_remount_ro) { |
| /* We always try to remount directories |
| * read-only first, before we go on and umount |
| * them. |
| * |
| * Mount points can be stacked. If a mount |
| * point is stacked below / or /usr, we |
| * cannot umount or remount it directly, |
| * since there is no way to refer to the |
| * underlying mount. There's nothing we can do |
| * about it for the general case, but we can |
| * do something about it if it is aliased |
| * somehwere else via a bind mount. If we |
| * explicitly remount the super block of that |
| * alias read-only we hence should be |
| * relatively safe regarding keeping a dirty fs |
| * we cannot otherwise see. |
| * |
| * Since the remount can hang in the instance of |
| * remote filesystems, we remount asynchronously |
| * and skip the subsequent umount if it fails. */ |
| if (remount_with_timeout(m, umount_log_level) < 0) { |
| /* Remount failed, but try unmounting anyway, |
| * unless this is a mount point we want to skip. */ |
| if (nonunmountable_path(m->path)) { |
| n_failed++; |
| continue; |
| } |
| } |
| } |
| |
| /* Skip / and /usr since we cannot unmount that |
| * anyway, since we are running from it. They have |
| * already been remounted ro. */ |
| if (nonunmountable_path(m->path)) |
| continue; |
| |
| /* Trying to umount */ |
| if (umount_with_timeout(m, umount_log_level) < 0) |
| n_failed++; |
| else |
| *changed = true; |
| } |
| |
| return n_failed; |
| } |
| |
| static int swap_points_list_off(MountPoint **head, bool *changed) { |
| MountPoint *m, *n; |
| int n_failed = 0; |
| |
| assert(head); |
| assert(changed); |
| |
| LIST_FOREACH_SAFE(mount_point, m, n, *head) { |
| log_info("Deactivating swap %s.", m->path); |
| if (swapoff(m->path) == 0) { |
| *changed = true; |
| mount_point_free(head, m); |
| } else { |
| log_warning_errno(errno, "Could not deactivate swap %s: %m", m->path); |
| n_failed++; |
| } |
| } |
| |
| return n_failed; |
| } |
| |
| static int loopback_points_list_detach(MountPoint **head, bool *changed, int umount_log_level) { |
| MountPoint *m, *n; |
| int n_failed = 0, k; |
| struct stat root_st; |
| |
| assert(head); |
| assert(changed); |
| |
| k = lstat("/", &root_st); |
| |
| LIST_FOREACH_SAFE(mount_point, m, n, *head) { |
| int r; |
| struct stat loopback_st; |
| |
| if (k >= 0 && |
| major(root_st.st_dev) != 0 && |
| lstat(m->path, &loopback_st) >= 0 && |
| root_st.st_dev == loopback_st.st_rdev) { |
| n_failed++; |
| continue; |
| } |
| |
| log_info("Detaching loopback %s.", m->path); |
| r = delete_loopback(m->path); |
| if (r >= 0) { |
| if (r > 0) |
| *changed = true; |
| |
| mount_point_free(head, m); |
| } else { |
| log_full_errno(umount_log_level, errno, "Could not detach loopback %s: %m", m->path); |
| n_failed++; |
| } |
| } |
| |
| return n_failed; |
| } |
| |
| static int dm_points_list_detach(MountPoint **head, bool *changed, int umount_log_level) { |
| MountPoint *m, *n; |
| int n_failed = 0, r; |
| dev_t rootdev; |
| |
| assert(head); |
| assert(changed); |
| |
| r = get_block_device("/", &rootdev); |
| if (r <= 0) |
| rootdev = 0; |
| |
| LIST_FOREACH_SAFE(mount_point, m, n, *head) { |
| |
| if (major(rootdev) != 0 && rootdev == m->devnum) { |
| n_failed ++; |
| continue; |
| } |
| |
| log_info("Detaching DM %u:%u.", major(m->devnum), minor(m->devnum)); |
| r = delete_dm(m->devnum); |
| if (r >= 0) { |
| *changed = true; |
| mount_point_free(head, m); |
| } else { |
| log_full_errno(umount_log_level, errno, "Could not detach DM %s: %m", m->path); |
| n_failed++; |
| } |
| } |
| |
| return n_failed; |
| } |
| |
| static int umount_all_once(bool *changed, int umount_log_level) { |
| int r; |
| _cleanup_(mount_points_list_free) LIST_HEAD(MountPoint, mp_list_head); |
| |
| assert(changed); |
| |
| LIST_HEAD_INIT(mp_list_head); |
| r = mount_points_list_get(NULL, &mp_list_head); |
| if (r < 0) |
| return r; |
| |
| return mount_points_list_umount(&mp_list_head, changed, umount_log_level); |
| } |
| |
| int umount_all(bool *changed, int umount_log_level) { |
| bool umount_changed; |
| int r; |
| |
| assert(changed); |
| |
| /* Retry umount, until nothing can be umounted anymore. Mounts are |
| * processed in order, newest first. The retries are needed when |
| * an old mount has been moved, to a path inside a newer mount. */ |
| do { |
| umount_changed = false; |
| |
| r = umount_all_once(&umount_changed, umount_log_level); |
| if (umount_changed) |
| *changed = true; |
| } while (umount_changed); |
| |
| return r; |
| } |
| |
| int swapoff_all(bool *changed) { |
| _cleanup_(mount_points_list_free) LIST_HEAD(MountPoint, swap_list_head); |
| int r; |
| |
| assert(changed); |
| |
| LIST_HEAD_INIT(swap_list_head); |
| |
| r = swap_list_get(NULL, &swap_list_head); |
| if (r < 0) |
| return r; |
| |
| return swap_points_list_off(&swap_list_head, changed); |
| } |
| |
| int loopback_detach_all(bool *changed, int umount_log_level) { |
| _cleanup_(mount_points_list_free) LIST_HEAD(MountPoint, loopback_list_head); |
| int r; |
| |
| assert(changed); |
| |
| LIST_HEAD_INIT(loopback_list_head); |
| |
| r = loopback_list_get(&loopback_list_head); |
| if (r < 0) |
| return r; |
| |
| return loopback_points_list_detach(&loopback_list_head, changed, umount_log_level); |
| } |
| |
| int dm_detach_all(bool *changed, int umount_log_level) { |
| _cleanup_(mount_points_list_free) LIST_HEAD(MountPoint, dm_list_head); |
| int r; |
| |
| assert(changed); |
| |
| LIST_HEAD_INIT(dm_list_head); |
| |
| r = dm_list_get(&dm_list_head); |
| if (r < 0) |
| return r; |
| |
| return dm_points_list_detach(&dm_list_head, changed, umount_log_level); |
| } |