[systemd-devel] [PATCH 2/4] Adding unmount functions to be used in shutdown

fidencio at profusion.mobi fidencio at profusion.mobi
Thu Sep 30 14:10:46 PDT 2010


From: Fabiano Fidencio <fidencio at profusion.mobi>

This functions will unmount all filesystem that aren't api
(and those which fail will be remounted read-only).
Filesystems are being read from /proc/self/mountinfo.
---
 Makefile.am  |    1 +
 src/umount.c |  183 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/umount.h |   27 +++++++++
 3 files changed, 211 insertions(+), 0 deletions(-)
 create mode 100644 src/umount.c
 create mode 100644 src/umount.h

diff --git a/Makefile.am b/Makefile.am
index 0a33c06..06b2cca 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -349,6 +349,7 @@ libsystemd_core_la_SOURCES = \
 	src/service.c \
 	src/automount.c \
 	src/mount.c \
+	src/umount.c \
 	src/swap.c \
 	src/device.c \
 	src/target.c \
diff --git a/src/umount.c b/src/umount.c
new file mode 100644
index 0000000..e017474
--- /dev/null
+++ b/src/umount.c
@@ -0,0 +1,183 @@
+/*-*- 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 <sys/mount.h>
+#include <string.h>
+#include <errno.h>
+#include <unistd.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;
+        int r, i;
+
+        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;
+
+                        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 void mount_points_list_umount(MountPoint **mount_point_list_head, bool *changed) {
+        MountPoint *mp, *mp_next;
+
+        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) {
+                        *changed = true;
+                        mount_point_remove_and_free(mp, mount_point_list_head);
+                }
+        }
+}
+
+static int mount_points_list_remount_read_only(MountPoint **mount_point_list_head, bool *changed) {
+        MountPoint *mp, *mp_next;
+        int r = 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;
+                        *changed = true;
+                        mount_point_remove_and_free(mp, mount_point_list_head);
+                } else
+                        r = -1;
+        }
+
+        return r;
+}
+
+int umount_init(void) {
+        LIST_HEAD(MountPoint, mp_list_head);
+        int r;
+        bool changed;
+
+        /* Preventing that we won't block umounts */
+        if ((chdir("/")) == -1)
+                return -1;
+
+        LIST_HEAD_INIT(MountPoint, mp_list_head);
+        if (mount_points_list_get(&mp_list_head) < 0)
+                return -1;
+
+        for (changed = false; changed;)
+                mount_points_list_umount(&mp_list_head, &changed);
+
+        for (changed = false; changed;)
+                r = mount_points_list_remount_read_only(&mp_list_head, &changed);
+
+        mount_points_list_free(&mp_list_head);
+
+        return r;
+}
diff --git a/src/umount.h b/src/umount.h
new file mode 100644
index 0000000..37f4e24
--- /dev/null
+++ b/src/umount.h
@@ -0,0 +1,27 @@
+/*-*- 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_init(void);
+
+#endif
-- 
1.7.3



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