X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=src%2Fumount.c;h=4e036d82a30555988c18fea2c4dc8a8333f4b78c;hp=c95f72760bccf4f3e833ef9159f49a42432d7205;hb=cd0504d0a13d8297b97c9238fd1b94b4141c5aa8;hpb=2d9a33978247b1b640919ad5924fe270b9ddf9a1

diff --git a/src/umount.c b/src/umount.c
index c95f72760..4e036d82a 100644
--- a/src/umount.c
+++ b/src/umount.c
@@ -37,33 +37,43 @@
 typedef struct MountPoint {
         char *path;
         dev_t devnum;
+        bool skip_ro;
         LIST_FIELDS (struct MountPoint, mount_point);
 } MountPoint;
 
-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);
+static void mount_point_free(MountPoint **head, MountPoint *m) {
+        assert(head);
+        assert(m);
 
-        free(mount_point->path);
-        free(mount_point);
+        LIST_REMOVE(MountPoint, mount_point, *head, m);
+
+        free(m->path);
+        free(m);
 }
 
-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 void mount_points_list_free(MountPoint **head) {
+        assert(head);
+
+        while (*head)
+                mount_point_free(head, *head);
 }
 
-static int mount_points_list_get(MountPoint **mount_point_list_head) {
+static int mount_points_list_get(MountPoint **head) {
         FILE *proc_self_mountinfo;
         char *path, *p;
         unsigned int i;
         int r;
 
+        assert(head);
+
         if (!(proc_self_mountinfo = fopen("/proc/self/mountinfo", "re")))
                 return -errno;
 
         for (i = 1;; i++) {
                 int k;
-                MountPoint *mp;
+                MountPoint *m;
+                char *root;
+                bool skip_ro;
 
                 path = p = NULL;
 
@@ -71,7 +81,7 @@ static int mount_points_list_get(MountPoint **mount_point_list_head) {
                                 "%*s "       /* (1) mount id */
                                 "%*s "       /* (2) parent id */
                                 "%*s "       /* (3) major:minor */
-                                "%*s "       /* (4) root */
+                                "%ms "       /* (4) root */
                                 "%ms "       /* (5) mount point */
                                 "%*s"        /* (6) mount options */
                                 "%*[^-]"     /* (7) optional fields */
@@ -80,7 +90,8 @@ static int mount_points_list_get(MountPoint **mount_point_list_head) {
                                 "%*s"        /* (10) mount source */
                                 "%*s"        /* (11) mount options 2 */
                                 "%*[^\n]",   /* some rubbish at the end */
-                                &path)) != 1) {
+                                &root,
+                                &path)) != 2) {
                         if (k == EOF)
                                 break;
 
@@ -90,6 +101,11 @@ static int mount_points_list_get(MountPoint **mount_point_list_head) {
                         continue;
                 }
 
+                /* If we encounter a bind mount, don't try to remount
+                 * the source dir too early */
+                skip_ro = !streq(root, "/");
+                free(root);
+
                 p = cunescape(path);
                 free(path);
 
@@ -98,19 +114,20 @@ static int mount_points_list_get(MountPoint **mount_point_list_head) {
                         goto finish;
                 }
 
-                if (mount_point_is_api(p)) {
+                if (mount_point_is_api(p) || mount_point_ignore(p)) {
                         free(p);
                         continue;
                 }
 
-                if (!(mp = new0(MountPoint, 1))) {
+                if (!(m = new0(MountPoint, 1))) {
                         free(p);
                         r = -ENOMEM;
                         goto finish;
                 }
 
-                mp->path = p;
-                LIST_PREPEND(MountPoint, mount_point, *mount_point_list_head, mp);
+                m->path = p;
+                m->skip_ro = skip_ro;
+                LIST_PREPEND(MountPoint, mount_point, *head, m);
         }
 
         r = 0;
@@ -121,13 +138,15 @@ finish:
         return r;
 }
 
-static int swap_list_get(MountPoint **swap_list_head) {
+static int swap_list_get(MountPoint **head) {
         FILE *proc_swaps;
         unsigned int i;
         int r;
 
+        assert(head);
+
         if (!(proc_swaps = fopen("/proc/swaps", "re")))
-                return -errno;
+                return (errno == ENOENT) ? 0 : -errno;
 
         (void) fscanf(proc_swaps, "%*s %*s %*s %*s %*s\n");
 
@@ -173,7 +192,7 @@ static int swap_list_get(MountPoint **swap_list_head) {
                 }
 
                 swap->path = d;
-                LIST_PREPEND(MountPoint, mount_point, *swap_list_head, swap);
+                LIST_PREPEND(MountPoint, mount_point, *head, swap);
         }
 
         r = 0;
@@ -184,12 +203,14 @@ finish:
         return r;
 }
 
-static int loopback_list_get(MountPoint **loopback_list_head) {
+static int loopback_list_get(MountPoint **head) {
         int r;
         struct udev *udev;
         struct udev_enumerate *e = NULL;
         struct udev_list_entry *item = NULL, *first = NULL;
 
+        assert(head);
+
         if (!(udev = udev_new())) {
                 r = -ENOMEM;
                 goto finish;
@@ -212,7 +233,6 @@ static int loopback_list_get(MountPoint **loopback_list_head) {
         }
 
         first = udev_enumerate_get_list_entry(e);
-
         udev_list_entry_foreach(item, first) {
                 MountPoint *lb;
                 struct udev_device *d;
@@ -244,7 +264,7 @@ static int loopback_list_get(MountPoint **loopback_list_head) {
                 }
 
                 lb->path = loop;
-                LIST_PREPEND(MountPoint, mount_point, *loopback_list_head, lb);
+                LIST_PREPEND(MountPoint, mount_point, *head, lb);
         }
 
         r = 0;
@@ -259,12 +279,14 @@ finish:
         return r;
 }
 
-static int dm_list_get(MountPoint **dm_list_head) {
+static int dm_list_get(MountPoint **head) {
         int r;
         struct udev *udev;
         struct udev_enumerate *e = NULL;
         struct udev_list_entry *item = NULL, *first = NULL;
 
+        assert(head);
+
         if (!(udev = udev_new())) {
                 r = -ENOMEM;
                 goto finish;
@@ -324,7 +346,7 @@ static int dm_list_get(MountPoint **dm_list_head) {
 
                 m->path = node;
                 m->devnum = devnum;
-                LIST_PREPEND(MountPoint, mount_point, *dm_list_head, m);
+                LIST_PREPEND(MountPoint, mount_point, *head, m);
         }
 
         r = 0;
@@ -343,13 +365,19 @@ static int delete_loopback(const char *device) {
         int fd, r;
 
         if ((fd = open(device, O_RDONLY|O_CLOEXEC)) < 0)
-                return -errno;
+                return errno == ENOENT ? 0 : -errno;
 
         r = ioctl(fd, LOOP_CLR_FD, 0);
         close_nointr_nofail(fd);
 
+        if (r >= 0)
+                return 1;
+
         /* ENXIO: not bound, so no error */
-        return (r >= 0 || errno == ENXIO) ? 0 : -errno;
+        if (errno == ENXIO)
+                return 0;
+
+        return -errno;
 }
 
 static int delete_dm(dev_t devnum) {
@@ -375,93 +403,157 @@ static int delete_dm(dev_t devnum) {
         return r >= 0 ? 0 : -errno;
 }
 
-static int mount_points_list_umount(MountPoint **mount_point_list_head) {
-        MountPoint *mp, *mp_next;
-        int failed = 0;
+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, mp, mp_next, *mount_point_list_head) {
-                if (streq(mp->path, "/"))
+        LIST_FOREACH_SAFE(mount_point, m, n, *head) {
+                if (streq(m->path, "/")) {
+                        n_failed++;
                         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_warning("Could not unmount %s: %m", mp->path);
-                        failed++;
+                if (umount2(m->path, MNT_FORCE) == 0) {
+                        log_info("Unmounted %s.", m->path);
+                        if (changed)
+                                *changed = true;
+
+                        mount_point_free(head, m);
+                } else if (log_error) {
+                        log_warning("Could not unmount %s: %m", m->path);
+                        n_failed++;
                 }
         }
 
-        return failed;
+        return n_failed;
 }
 
-static int mount_points_list_remount_read_only(MountPoint **mount_point_list_head) {
-        MountPoint *mp, *mp_next;
-        int failed = 0;
+static int mount_points_list_remount_read_only(MountPoint **head, bool *changed) {
+        MountPoint *m, *n;
+        int n_failed = 0;
+
+        assert(head);
+
+        LIST_FOREACH_SAFE(mount_point, m, n, *head) {
+
+                if (m->skip_ro) {
+                        n_failed++;
+                        continue;
+                }
 
-        LIST_FOREACH_SAFE(mount_point, mp, mp_next, *mount_point_list_head) {
                 /* Trying to remount read-only */
-                if (mount(NULL, mp->path, NULL, MS_MGC_VAL|MS_REMOUNT|MS_RDONLY, NULL) == 0)
-                        mount_point_remove_and_free(mp, mount_point_list_head);
-                else {
-                        log_warning("Could not remount as read-only %s: %m", mp->path);
-                        failed++;
+                if (mount(NULL, m->path, NULL, MS_MGC_VAL|MS_REMOUNT|MS_RDONLY, NULL) == 0) {
+                        if (changed)
+                                *changed = true;
+
+                        mount_point_free(head, m);
+                } else {
+                        log_warning("Could not remount as read-only %s: %m", m->path);
+                        n_failed++;
                 }
         }
 
-        return failed;
+        return n_failed;
 }
 
-static int swap_points_list_off(MountPoint **swap_list_head) {
-        MountPoint *swap, *swap_next;
-        int failed = 0;
+static int swap_points_list_off(MountPoint **head, bool *changed) {
+        MountPoint *m, *n;
+        int n_failed = 0;
+
+        assert(head);
 
-        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_warning("Could not deactivate swap %s: %m", swap->path);
-                        failed++;
+        LIST_FOREACH_SAFE(mount_point, m, n, *head) {
+                if (swapoff(m->path) == 0) {
+                        if (changed)
+                                *changed = true;
+
+                        mount_point_free(head, m);
+                } else {
+                        log_warning("Could not deactivate swap %s: %m", m->path);
+                        n_failed++;
                 }
         }
 
-        return failed;
+        return n_failed;
 }
 
-static int loopback_points_list_detach(MountPoint **loopback_list_head) {
-        MountPoint *loopback, *loopback_next;
-        int failed = 0;
+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, loopback, loopback_next, *loopback_list_head) {
-                if (delete_loopback(loopback->path) == 0)
-                        mount_point_remove_and_free(loopback, loopback_list_head);
-                else {
-                        log_warning("Could not delete loopback %s: %m", loopback->path);
-                        failed++;
+        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;
+                }
+
+                if ((r = delete_loopback(m->path)) >= 0) {
+
+                        if (r > 0 && changed)
+                                *changed = true;
+
+                        mount_point_free(head, m);
+                } else {
+                        log_warning("Could not delete loopback %s: %m", m->path);
+                        n_failed++;
                 }
         }
 
-        return failed;
+        return n_failed;
 }
 
-static int dm_points_list_detach(MountPoint **dm_list_head) {
-        MountPoint *dm, *dm_next;
-        int failed = 0;
+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, dm, dm_next, *dm_list_head) {
-                if (delete_dm(dm->devnum) == 0)
-                        mount_point_remove_and_free(dm, dm_list_head);
-                else {
-                        log_warning("Could not delete dm %s: %m", dm->path);
-                        failed++;
+        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;
+                }
+
+                if ((r = delete_dm(m->devnum)) >= 0) {
+
+                        if (r > 0 && changed)
+                                *changed = true;
+
+                        mount_point_free(head, m);
+                } else {
+                        log_warning("Could not delete dm %s: %m", m->path);
+                        n_failed++;
                 }
         }
 
-        return failed;
+        return n_failed;
 }
 
-int umount_all(void) {
+int umount_all(bool *changed) {
         int r;
+        bool umount_changed;
+
         LIST_HEAD(MountPoint, mp_list_head);
 
         LIST_HEAD_INIT(MountPoint, mp_list_head);
@@ -470,11 +562,22 @@ int umount_all(void) {
         if (r < 0)
                 goto end;
 
-        r = mount_points_list_umount(&mp_list_head);
+        /* 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;
 
-        r = mount_points_list_remount_read_only(&mp_list_head);
+        r = mount_points_list_remount_read_only(&mp_list_head, changed);
 
   end:
         mount_points_list_free(&mp_list_head);
@@ -482,7 +585,7 @@ int umount_all(void) {
         return r;
 }
 
-int swapoff_all(void) {
+int swapoff_all(bool *changed) {
         int r;
         LIST_HEAD(MountPoint, swap_list_head);
 
@@ -492,7 +595,7 @@ int swapoff_all(void) {
         if (r < 0)
                 goto end;
 
-        r = swap_points_list_off(&swap_list_head);
+        r = swap_points_list_off(&swap_list_head, changed);
 
   end:
         mount_points_list_free(&swap_list_head);
@@ -500,7 +603,7 @@ int swapoff_all(void) {
         return r;
 }
 
-int loopback_detach_all(void) {
+int loopback_detach_all(bool *changed) {
         int r;
         LIST_HEAD(MountPoint, loopback_list_head);
 
@@ -510,7 +613,7 @@ int loopback_detach_all(void) {
         if (r < 0)
                 goto end;
 
-        r = loopback_points_list_detach(&loopback_list_head);
+        r = loopback_points_list_detach(&loopback_list_head, changed);
 
   end:
         mount_points_list_free(&loopback_list_head);
@@ -518,7 +621,7 @@ int loopback_detach_all(void) {
         return r;
 }
 
-int dm_detach_all(void) {
+int dm_detach_all(bool *changed) {
         int r;
         LIST_HEAD(MountPoint, dm_list_head);
 
@@ -528,7 +631,7 @@ int dm_detach_all(void) {
         if (r < 0)
                 goto end;
 
-        r = dm_points_list_detach(&dm_list_head);
+        r = dm_points_list_detach(&dm_list_head, changed);
 
   end:
         mount_points_list_free(&dm_list_head);