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-rw-r--r--src/systemd-shutdown/umount.c614
1 files changed, 614 insertions, 0 deletions
diff --git a/src/systemd-shutdown/umount.c b/src/systemd-shutdown/umount.c
new file mode 100644
index 0000000000..c21a2be54e
--- /dev/null
+++ b/src/systemd-shutdown/umount.c
@@ -0,0 +1,614 @@
+/***
+ This file is part of systemd.
+
+ Copyright 2010 ProFUSION embedded systems
+
+ 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 <errno.h>
+#include <fcntl.h>
+#include <linux/dm-ioctl.h>
+#include <linux/loop.h>
+#include <string.h>
+#include <sys/mount.h>
+#include <sys/swap.h>
+
+#include "libudev.h"
+
+#include "alloc-util.h"
+#include "escape.h"
+#include "fd-util.h"
+#include "fstab-util.h"
+#include "list.h"
+#include "mount-setup.h"
+#include "path-util.h"
+#include "string-util.h"
+#include "udev-util.h"
+#include "umount.h"
+#include "util.h"
+#include "virt.h"
+
+typedef struct MountPoint {
+ char *path;
+ char *options;
+ dev_t devnum;
+ LIST_FIELDS(struct MountPoint, mount_point);
+} MountPoint;
+
+static void mount_point_free(MountPoint **head, MountPoint *m) {
+ assert(head);
+ assert(m);
+
+ LIST_REMOVE(mount_point, *head, m);
+
+ free(m->path);
+ free(m);
+}
+
+static void mount_points_list_free(MountPoint **head) {
+ assert(head);
+
+ while (*head)
+ mount_point_free(head, *head);
+}
+
+static int mount_points_list_get(MountPoint **head) {
+ _cleanup_fclose_ FILE *proc_self_mountinfo = NULL;
+ unsigned int i;
+ int r;
+
+ assert(head);
+
+ proc_self_mountinfo = fopen("/proc/self/mountinfo", "re");
+ if (!proc_self_mountinfo)
+ return -errno;
+
+ for (i = 1;; i++) {
+ _cleanup_free_ char *path = NULL, *options = NULL;
+ char *p = NULL;
+ MountPoint *m;
+ int k;
+
+ k = fscanf(proc_self_mountinfo,
+ "%*s " /* (1) mount id */
+ "%*s " /* (2) parent id */
+ "%*s " /* (3) major:minor */
+ "%*s " /* (4) root */
+ "%ms " /* (5) mount point */
+ "%*s" /* (6) mount flags */
+ "%*[^-]" /* (7) optional fields */
+ "- " /* (8) separator */
+ "%*s " /* (9) file system type */
+ "%*s" /* (10) mount source */
+ "%ms" /* (11) mount options */
+ "%*[^\n]", /* some rubbish at the end */
+ &path, &options);
+ if (k != 2) {
+ if (k == EOF)
+ break;
+
+ log_warning("Failed to parse /proc/self/mountinfo:%u.", i);
+ continue;
+ }
+
+ r = cunescape(path, UNESCAPE_RELAX, &p);
+ if (r < 0)
+ return r;
+
+ /* 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(p, "/dev") ||
+ path_startswith(p, "/sys") ||
+ path_startswith(p, "/proc")) {
+ free(p);
+ continue;
+ }
+
+ m = new0(MountPoint, 1);
+ if (!m) {
+ free(p);
+ return -ENOMEM;
+ }
+
+ m->path = p;
+ m->options = options;
+ options = NULL;
+
+ LIST_PREPEND(mount_point, *head, m);
+ }
+
+ return 0;
+}
+
+static int swap_list_get(MountPoint **head) {
+ _cleanup_fclose_ FILE *proc_swaps = NULL;
+ unsigned int i;
+ int r;
+
+ assert(head);
+
+ proc_swaps = fopen("/proc/swaps", "re");
+ if (!proc_swaps)
+ return (errno == ENOENT) ? 0 : -errno;
+
+ (void) fscanf(proc_swaps, "%*s %*s %*s %*s %*s\n");
+
+ for (i = 2;; i++) {
+ MountPoint *swap;
+ char *dev = NULL, *d;
+ int k;
+
+ k = fscanf(proc_swaps,
+ "%ms " /* device/file */
+ "%*s " /* type of swap */
+ "%*s " /* swap size */
+ "%*s " /* used */
+ "%*s\n", /* priority */
+ &dev);
+
+ if (k != 1) {
+ if (k == EOF)
+ break;
+
+ log_warning("Failed to parse /proc/swaps:%u.", i);
+ free(dev);
+ continue;
+ }
+
+ if (endswith(dev, " (deleted)")) {
+ free(dev);
+ continue;
+ }
+
+ r = cunescape(dev, UNESCAPE_RELAX, &d);
+ free(dev);
+ if (r < 0)
+ return r;
+
+ swap = new0(MountPoint, 1);
+ if (!swap) {
+ free(d);
+ return -ENOMEM;
+ }
+
+ swap->path = d;
+ LIST_PREPEND(mount_point, *head, swap);
+ }
+
+ return 0;
+}
+
+static int loopback_list_get(MountPoint **head) {
+ _cleanup_udev_enumerate_unref_ struct udev_enumerate *e = NULL;
+ struct udev_list_entry *item = NULL, *first = NULL;
+ _cleanup_udev_unref_ struct udev *udev = NULL;
+ int r;
+
+ assert(head);
+
+ udev = udev_new();
+ if (!udev)
+ return -ENOMEM;
+
+ e = udev_enumerate_new(udev);
+ if (!e)
+ return -ENOMEM;
+
+ r = udev_enumerate_add_match_subsystem(e, "block");
+ if (r < 0)
+ return r;
+
+ r = udev_enumerate_add_match_sysname(e, "loop*");
+ if (r < 0)
+ return r;
+
+ r = udev_enumerate_add_match_sysattr(e, "loop/backing_file", NULL);
+ if (r < 0)
+ return r;
+
+ r = udev_enumerate_scan_devices(e);
+ if (r < 0)
+ return r;
+
+ first = udev_enumerate_get_list_entry(e);
+ udev_list_entry_foreach(item, first) {
+ MountPoint *lb;
+ _cleanup_udev_device_unref_ struct udev_device *d;
+ char *loop;
+ const char *dn;
+
+ d = udev_device_new_from_syspath(udev, udev_list_entry_get_name(item));
+ if (!d)
+ return -ENOMEM;
+
+ dn = udev_device_get_devnode(d);
+ if (!dn)
+ continue;
+
+ loop = strdup(dn);
+ if (!loop)
+ return -ENOMEM;
+
+ lb = new0(MountPoint, 1);
+ if (!lb) {
+ free(loop);
+ return -ENOMEM;
+ }
+
+ lb->path = loop;
+ LIST_PREPEND(mount_point, *head, lb);
+ }
+
+ return 0;
+}
+
+static int dm_list_get(MountPoint **head) {
+ _cleanup_udev_enumerate_unref_ struct udev_enumerate *e = NULL;
+ struct udev_list_entry *item = NULL, *first = NULL;
+ _cleanup_udev_unref_ struct udev *udev = NULL;
+ int r;
+
+ assert(head);
+
+ udev = udev_new();
+ if (!udev)
+ return -ENOMEM;
+
+ e = udev_enumerate_new(udev);
+ if (!e)
+ return -ENOMEM;
+
+ r = udev_enumerate_add_match_subsystem(e, "block");
+ if (r < 0)
+ return r;
+
+ r = udev_enumerate_add_match_sysname(e, "dm-*");
+ if (r < 0)
+ return r;
+
+ r = udev_enumerate_scan_devices(e);
+ if (r < 0)
+ return r;
+
+ first = udev_enumerate_get_list_entry(e);
+ udev_list_entry_foreach(item, first) {
+ MountPoint *m;
+ _cleanup_udev_device_unref_ struct udev_device *d;
+ dev_t devnum;
+ char *node;
+ const char *dn;
+
+ d = udev_device_new_from_syspath(udev, udev_list_entry_get_name(item));
+ if (!d)
+ return -ENOMEM;
+
+ devnum = udev_device_get_devnum(d);
+ dn = udev_device_get_devnode(d);
+ if (major(devnum) == 0 || !dn)
+ continue;
+
+ node = strdup(dn);
+ if (!node)
+ return -ENOMEM;
+
+ m = new(MountPoint, 1);
+ if (!m) {
+ free(node);
+ return -ENOMEM;
+ }
+
+ m->path = node;
+ m->devnum = devnum;
+ LIST_PREPEND(mount_point, *head, m);
+ }
+
+ return 0;
+}
+
+static int delete_loopback(const char *device) {
+ _cleanup_close_ int fd = -1;
+ int r;
+
+ 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) {
+ _cleanup_close_ int fd = -1;
+ int r;
+ struct dm_ioctl dm = {
+ .version = {DM_VERSION_MAJOR,
+ DM_VERSION_MINOR,
+ DM_VERSION_PATCHLEVEL},
+ .data_size = sizeof(dm),
+ .dev = devnum,
+ };
+
+ assert(major(devnum) != 0);
+
+ fd = open("/dev/mapper/control", O_RDWR|O_CLOEXEC);
+ if (fd < 0)
+ return -errno;
+
+ r = ioctl(fd, DM_DEV_REMOVE, &dm);
+ return r >= 0 ? 0 : -errno;
+}
+
+static int mount_points_list_umount(MountPoint **head, bool *changed, bool log_error) {
+ MountPoint *m, *n;
+ int n_failed = 0;
+
+ assert(head);
+
+ LIST_FOREACH_SAFE(mount_point, m, n, *head) {
+
+ /* 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 mound. */
+ if (detect_container() <= 0) {
+ _cleanup_free_ char *options = NULL;
+ /* MS_REMOUNT requires that the data parameter
+ * should be the same from the original mount
+ * except for the desired changes. Since we want
+ * to remount read-only, we should filter out
+ * rw (and ro too, because it confuses the kernel) */
+ (void) fstab_filter_options(m->options, "rw\0ro\0", NULL, NULL, &options);
+
+ /* 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 the fs we
+ * can otherwise not see dirty. */
+ log_info("Remounting '%s' read-only with options '%s'.", m->path, options);
+ (void) mount(NULL, m->path, NULL, MS_REMOUNT|MS_RDONLY, options);
+ }
+
+ /* Skip / and /usr since we cannot unmount that
+ * anyway, since we are running from it. They have
+ * already been remounted ro. */
+ if (path_equal(m->path, "/")
+#ifndef HAVE_SPLIT_USR
+ || path_equal(m->path, "/usr")
+#endif
+ || path_startswith(m->path, "/run/initramfs")
+ )
+ continue;
+
+ /* Trying to umount. We don't force here since we rely
+ * on busy NFS and FUSE file systems to return EBUSY
+ * until we closed everything on top of them. */
+ log_info("Unmounting %s.", m->path);
+ if (umount2(m->path, 0) == 0) {
+ if (changed)
+ *changed = true;
+
+ mount_point_free(head, m);
+ } else if (log_error) {
+ log_warning_errno(errno, "Could not unmount %s: %m", m->path);
+ n_failed++;
+ }
+ }
+
+ return n_failed;
+}
+
+static int swap_points_list_off(MountPoint **head, bool *changed) {
+ MountPoint *m, *n;
+ int n_failed = 0;
+
+ assert(head);
+
+ LIST_FOREACH_SAFE(mount_point, m, n, *head) {
+ log_info("Deactivating swap %s.", m->path);
+ if (swapoff(m->path) == 0) {
+ if (changed)
+ *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) {
+ MountPoint *m, *n;
+ int n_failed = 0, k;
+ struct stat root_st;
+
+ assert(head);
+
+ 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)
+ *changed = true;
+
+ mount_point_free(head, m);
+ } else {
+ log_warning_errno(errno, "Could not detach loopback %s: %m", m->path);
+ n_failed++;
+ }
+ }
+
+ return n_failed;
+}
+
+static int dm_points_list_detach(MountPoint **head, bool *changed) {
+ MountPoint *m, *n;
+ int n_failed = 0, k;
+ struct stat root_st;
+
+ assert(head);
+
+ k = lstat("/", &root_st);
+
+ LIST_FOREACH_SAFE(mount_point, m, n, *head) {
+ int r;
+
+ if (k >= 0 &&
+ major(root_st.st_dev) != 0 &&
+ root_st.st_dev == 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) {
+ if (changed)
+ *changed = true;
+
+ mount_point_free(head, m);
+ } else {
+ log_warning_errno(errno, "Could not detach DM %s: %m", m->path);
+ n_failed++;
+ }
+ }
+
+ return n_failed;
+}
+
+int umount_all(bool *changed) {
+ int r;
+ bool umount_changed;
+ LIST_HEAD(MountPoint, mp_list_head);
+
+ LIST_HEAD_INIT(mp_list_head);
+ r = mount_points_list_get(&mp_list_head);
+ if (r < 0)
+ goto end;
+
+ /* retry umount, until nothing can be umounted anymore */
+ do {
+ umount_changed = false;
+
+ mount_points_list_umount(&mp_list_head, &umount_changed, false);
+ if (umount_changed)
+ *changed = true;
+
+ } while (umount_changed);
+
+ /* umount one more time with logging enabled */
+ r = mount_points_list_umount(&mp_list_head, &umount_changed, true);
+ if (r <= 0)
+ goto end;
+
+ end:
+ mount_points_list_free(&mp_list_head);
+
+ return r;
+}
+
+int swapoff_all(bool *changed) {
+ int r;
+ LIST_HEAD(MountPoint, swap_list_head);
+
+ LIST_HEAD_INIT(swap_list_head);
+
+ r = swap_list_get(&swap_list_head);
+ if (r < 0)
+ goto end;
+
+ r = swap_points_list_off(&swap_list_head, changed);
+
+ end:
+ mount_points_list_free(&swap_list_head);
+
+ return r;
+}
+
+int loopback_detach_all(bool *changed) {
+ int r;
+ LIST_HEAD(MountPoint, loopback_list_head);
+
+ LIST_HEAD_INIT(loopback_list_head);
+
+ r = loopback_list_get(&loopback_list_head);
+ if (r < 0)
+ goto end;
+
+ r = loopback_points_list_detach(&loopback_list_head, changed);
+
+ end:
+ mount_points_list_free(&loopback_list_head);
+
+ return r;
+}
+
+int dm_detach_all(bool *changed) {
+ int r;
+ LIST_HEAD(MountPoint, dm_list_head);
+
+ LIST_HEAD_INIT(dm_list_head);
+
+ r = dm_list_get(&dm_list_head);
+ if (r < 0)
+ goto end;
+
+ r = dm_points_list_detach(&dm_list_head, changed);
+
+ end:
+ mount_points_list_free(&dm_list_head);
+
+ return r;
+}
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-11-03 12:11:34 +0000