[systemd-devel] [PATCH 2/4] Adding unmount functions to be used in shutdown
fidencio at profusion.mobi
fidencio at profusion.mobi
Wed Oct 6 21:03:35 PDT 2010
From: Fabiano Fidencio <fidencio at profusion.mobi>
This functions will:
- umount all mount points that aren't API
- remount read-only all mount points that can't be umounted
- umount all swap devices.
- detach all loopback devices
TODO:
- umount dms
Mountpoints are being read from /proc/self/mountinfo.
Swaps are being read from /proc/swaps.
Loop devices from /sys/class/block/loop*.
---
.gitignore | 1 +
src/umount.c | 411 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
src/umount.h | 31 +++++
3 files changed, 443 insertions(+), 0 deletions(-)
create mode 100644 src/umount.c
create mode 100644 src/umount.h
diff --git a/.gitignore b/.gitignore
index 9ba0758..2ba000c 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,4 @@
+systemd-shutdown
systemd-tmpfiles
systemd-readahead-collect
systemd-readahead-replay
diff --git a/src/umount.c b/src/umount.c
new file mode 100644
index 0000000..386b72f
--- /dev/null
+++ b/src/umount.c
@@ -0,0 +1,411 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+ 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 General Public License as published by
+ the Free Software Foundation; either version 2 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
+ General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <errno.h>
+#include <fcntl.h>
+#include <string.h>
+#include <sys/mount.h>
+#include <sys/swap.h>
+#include <unistd.h>
+#include <linux/loop.h>
+#include <libudev.h>
+
+#include "list.h"
+#include "mount-setup.h"
+#include "umount.h"
+#include "util.h"
+
+typedef struct MountPoint {
+ char *path;
+ bool read_only;
+ LIST_FIELDS (struct MountPoint, mount_point);
+} MountPoint;
+
+static MountPoint *mount_point_alloc(char *path) {
+ MountPoint *mp;
+
+ if (!(mp = new(MountPoint, 1)))
+ return NULL;
+
+ mp->path = path;
+ mp->read_only = false;
+
+ return mp;
+}
+
+static void mount_point_remove_and_free(MountPoint *mount_point, MountPoint **mount_point_list_head) {
+ LIST_REMOVE(MountPoint, mount_point, *mount_point_list_head, mount_point);
+
+ free(mount_point->path);
+ free(mount_point);
+}
+
+static void mount_points_list_free(MountPoint **mount_point_list_head) {
+ while (*mount_point_list_head)
+ mount_point_remove_and_free(*mount_point_list_head, mount_point_list_head);
+}
+
+static int mount_points_list_get(MountPoint **mount_point_list_head) {
+ FILE *proc_self_mountinfo;
+ char *path, *p;
+ unsigned int i;
+ int r;
+
+ if (!(proc_self_mountinfo = fopen("/proc/self/mountinfo", "re")))
+ return -errno;
+
+ for (i = 1;; i++) {
+ int k;
+ MountPoint *mp;
+
+ path = p = NULL;
+
+ if ((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 options */
+ "%*[^-]" /* (7) optional fields */
+ "- " /* (8) separator */
+ "%*s " /* (9) file system type */
+ "%*s" /* (10) mount source */
+ "%*s" /* (11) mount options 2 */
+ "%*[^\n]", /* some rubbish at the end */
+ &path)) != 1) {
+ if (k == EOF)
+ break;
+
+ log_warning("Failed to parse /proc/self/mountinfo:%u.", i);
+
+ free(path);
+ continue;
+ }
+
+ if (mount_point_is_api(path)) {
+ free(path);
+ continue;
+ }
+
+ if (!(p = cunescape(path))) {
+ r = -ENOMEM;
+ goto finish;
+ }
+
+ if (!(mp = mount_point_alloc(p))) {
+ r = -ENOMEM;
+ goto finish;
+ }
+ LIST_PREPEND(MountPoint, mount_point, *mount_point_list_head, mp);
+
+ free(path);
+ }
+
+ r = 0;
+
+finish:
+ fclose(proc_self_mountinfo);
+
+ free(path);
+
+ return r;
+}
+
+static int swap_list_get(MountPoint **swap_list_head) {
+ FILE *proc_swaps;
+ unsigned int i;
+ int r;
+
+ if (!(proc_swaps = fopen("/proc/swaps", "re")))
+ return -errno;
+
+ (void) fscanf(proc_swaps, "%*s %*s %*s %*s %*s\n");
+
+ for (i = 2;; i++) {
+ MountPoint *swap;
+ char *dev = NULL, *d;
+ int k;
+
+ if ((k = fscanf(proc_swaps,
+ "%ms " /* device/file */
+ "%*s " /* type of swap */
+ "%*s " /* swap size */
+ "%*s " /* used */
+ "%*s\n", /* priority */
+ &dev)) != 1) {
+
+ if (k == EOF)
+ break;
+
+ log_warning("Failed to parse /proc/swaps:%u.", i);
+
+ free(dev);
+ continue;
+ }
+
+ if (endswith(dev, "(deleted)")) {
+ free(dev);
+ continue;
+ }
+
+ d = cunescape(dev);
+ free(dev);
+
+ if (!d) {
+ r = -ENOMEM;
+ goto finish;
+ }
+
+ swap = mount_point_alloc(d);
+ if (!swap) {
+ free(d);
+ r = -ENOMEM;
+ goto finish;
+ }
+
+ LIST_PREPEND(MountPoint, mount_point, *swap_list_head, swap);
+ }
+
+ r = 0;
+
+finish:
+ fclose(proc_swaps);
+
+ return r;
+}
+
+static int loopback_list_get(MountPoint **loopback_list_head) {
+ int r;
+ struct udev *udev;
+ struct udev_enumerate *e = NULL;
+ struct udev_list_entry *item = NULL, *first = NULL;
+
+ if (!(udev = udev_new())) {
+ r = -ENOMEM;
+ goto finish;
+ }
+
+ if (!(e = udev_enumerate_new(udev))) {
+ r = -ENOMEM;
+ goto finish;
+ }
+
+ if (udev_enumerate_add_match_subsystem(e, "block") < 0) {
+ r = -EIO;
+ goto finish;
+ }
+
+ if (udev_enumerate_scan_devices(e) < 0) {
+ r = -EIO;
+ goto finish;
+ }
+
+ first = udev_enumerate_get_list_entry(e);
+
+ udev_list_entry_foreach(item, first) {
+ MountPoint *lb;
+ char buf[PATH_MAX];
+ char *loop;
+
+ snprintf(buf, sizeof(buf), "%s", udev_list_entry_get_name(item));
+ if (strstr(buf, "loop"))
+ loop = cunescape(buf);
+ else
+ continue;
+
+ if (!loop) {
+ r = -ENOMEM;
+ goto finish;
+ }
+
+ lb = mount_point_alloc(loop);
+ if (!lb) {
+ free(loop);
+ r = -ENOMEM;
+ goto finish;
+ }
+
+ LIST_PREPEND(MountPoint, mount_point, *loopback_list_head, lb);
+ }
+
+ r = 0;
+
+finish:
+ if (e)
+ udev_enumerate_unref(e);
+
+ free(udev);
+ return r;
+}
+
+static int delete_loopback(const char *device) {
+ int fd, r;
+
+ if ((fd = open(device, O_RDONLY|O_CLOEXEC)) < 0) {
+ if (errno == ENOENT) {
+ log_debug("Loop device %s does not exist.", device);
+ errno = 0;
+ return 0;
+ }
+ return -errno;
+ }
+
+ ioctl(fd, LOOP_CLR_FD, 0);
+ r = errno;
+ close_nointr(fd);
+
+ if (r == ENXIO) /* not bound, so no error */
+ r = 0;
+ errno = r;
+ return -errno;
+}
+
+static int mount_points_list_umount(MountPoint **mount_point_list_head) {
+ MountPoint *mp, *mp_next;
+ int failed = 0;
+
+ LIST_FOREACH_SAFE(mount_point, mp, mp_next, *mount_point_list_head) {
+ if (streq(mp->path, "/"))
+ continue;
+
+ /* Trying to umount. Forcing to umount if busy (only for NFS mounts) */
+ if (umount2(mp->path, MNT_FORCE) == 0)
+ mount_point_remove_and_free(mp, mount_point_list_head);
+ else {
+ log_debug("Could not unmount %s: %m", mp->path);
+ failed++;
+ }
+ }
+
+ return failed;
+}
+
+static int mount_points_list_remount_read_only(MountPoint **mount_point_list_head) {
+ MountPoint *mp, *mp_next;
+ int failed = 0;
+
+ LIST_FOREACH_SAFE(mount_point, mp, mp_next, *mount_point_list_head) {
+ if (mp->read_only)
+ continue;
+
+ /* Trying to remount read-only */
+ if (mount(NULL, mp->path, NULL, MS_MGC_VAL|MS_REMOUNT|MS_RDONLY, NULL) == 0) {
+ mp->read_only = true;
+ mount_point_remove_and_free(mp, mount_point_list_head);
+ } else {
+ log_debug("Could not remount as read-only %s: %m", mp->path);
+ failed++;
+ }
+ }
+
+ return failed;
+}
+
+static int swap_points_list_off(MountPoint **swap_list_head) {
+ MountPoint *swap, *swap_next;
+ int failed = 0;
+
+ LIST_FOREACH_SAFE(mount_point, swap, swap_next, *swap_list_head) {
+ if (swapoff(swap->path) == 0)
+ mount_point_remove_and_free(swap, swap_list_head);
+ else {
+ log_debug("Could not swapoff %s: %m", swap->path);
+ failed++;
+ }
+ }
+
+ return failed;
+}
+
+static int loopback_points_list_detach(MountPoint **loopback_list_head) {
+ MountPoint *loopback, *loopback_next;
+ int failed = 0;
+
+ LIST_FOREACH_SAFE(mount_point, loopback, loopback_next, *loopback_list_head) {
+ if (delete_loopback(loopback->path) == 0)
+ mount_point_remove_and_free(loopback, loopback_list_head);
+ else {
+ log_debug("Could not delete loopback %s: %m", loopback->path);
+ failed++;
+ }
+ }
+
+ return failed;
+}
+
+int umount_all(void) {
+ int r;
+ LIST_HEAD(MountPoint, mp_list_head);
+
+ LIST_HEAD_INIT(MountPoint, mp_list_head);
+
+ r = mount_points_list_get(&mp_list_head);
+ if (r < 0)
+ goto end;
+
+ r = mount_points_list_umount(&mp_list_head);
+ if (r <= 0)
+ goto end;
+
+ r = mount_points_list_remount_read_only(&mp_list_head);
+
+ end:
+ mount_points_list_free(&mp_list_head);
+
+ return r;
+}
+
+int swapoff_all(void) {
+ int r;
+ LIST_HEAD(MountPoint, swap_list_head);
+
+ LIST_HEAD_INIT(MountPoint, swap_list_head);
+
+ r = swap_list_get(&swap_list_head);
+ if (r < 0)
+ goto end;
+
+ r = swap_points_list_off(&swap_list_head);
+
+ end:
+ mount_points_list_free(&swap_list_head);
+
+ return r;
+}
+
+int loopback_detach_all(void) {
+ int r;
+ LIST_HEAD(MountPoint, loopback_list_head);
+
+ LIST_HEAD_INIT(MountPoint, loopback_list_head);
+
+ r = loopback_list_get(&loopback_list_head);
+ if (r < 0)
+ goto end;
+
+ r = loopback_points_list_detach(&loopback_list_head);
+
+ end:
+ mount_points_list_free(&loopback_list_head);
+
+ return r;
+}
diff --git a/src/umount.h b/src/umount.h
new file mode 100644
index 0000000..aeccc00
--- /dev/null
+++ b/src/umount.h
@@ -0,0 +1,31 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+#ifndef fooumounthfoo
+#define fooumounthfoo
+
+/***
+ 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 General Public License as published by
+ the Free Software Foundation; either version 2 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
+ General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+int umount_all(void);
+
+int swapoff_all(void);
+
+int loopback_detach_all(void);
+
+#endif
--
1.7.3
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