mount: update /etc/mtab properly on mount --move

Signed-off-by: Roman Borisov <ext-roman.borisov@nokia.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 67 insertions, 9 deletions

diff --git a/util-linux/mount.c b/util-linux/mount.c
index 0baa74c7c..0127f1958 100644
--- a/util-linux/mount.c
+++ b/util-linux/mount.c
@@ -279,6 +279,61 @@ enum { GETMNTENT_BUFSIZE = COMMON_BUFSIZE - offsetof(struct globals, getmntent_b
 #define fslist            (G.fslist           )
 #define getmntent_buf     (G.getmntent_buf    )
 
+#if ENABLE_FEATURE_MTAB_SUPPORT
+/*
+ * update_mtab_entry_on_move() is used to update entry in case of mount --move.
+ * we are looking for existing entries mnt_dir which is equal to mnt_fsname of
+ * input mntent and replace it by new one.
+ */
+static void FAST_FUNC update_mtab_entry_on_move(const struct mntent *mp)
+{
+        struct mntent *entries, *m;
+        int i, count;
+        FILE *mountTable;
+
+        mountTable = setmntent(bb_path_mtab_file, "r");
+        if (!mountTable) {
+                bb_perror_msg(bb_path_mtab_file);
+                return;
+        }
+
+        entries = NULL;
+        count = 0;
+        while ((m = getmntent(mountTable)) != NULL) {
+                entries = xrealloc_vector(entries, 3, count);
+                entries[count].mnt_fsname = xstrdup(m->mnt_fsname);
+                entries[count].mnt_dir = xstrdup(m->mnt_dir);
+                entries[count].mnt_type = xstrdup(m->mnt_type);
+                entries[count].mnt_opts = xstrdup(m->mnt_opts);
+                entries[count].mnt_freq = m->mnt_freq;
+                entries[count].mnt_passno = m->mnt_passno;
+                count++;
+        }
+        endmntent(mountTable);
+
+        mountTable = setmntent(bb_path_mtab_file, "w");
+        if (mountTable) {
+                for (i = 0; i < count; i++) {
+                        if (strcmp(entries[i].mnt_dir, mp->mnt_fsname) != 0)
+                                addmntent(mountTable, &entries[i]);
+                        else
+                                addmntent(mountTable, mp);
+                }
+                endmntent(mountTable);
+        } else if (errno != EROFS)
+                bb_perror_msg(bb_path_mtab_file);
+
+        if (ENABLE_FEATURE_CLEAN_UP) {
+                for (i = 0; i < count; i++) {
+                        free(entries[i].mnt_fsname);
+                        free(entries[i].mnt_dir);
+                        free(entries[i].mnt_type);
+                        free(entries[i].mnt_opts);
+                }
+                free(entries);
+        }
+}
+#endif
 
 #if ENABLE_FEATURE_MOUNT_VERBOSE
 static int verbose_mount(const char *source, const char *target,
@@ -496,12 +551,11 @@ static int mount_it_now(struct mntent *mp, long vfsflags, char *filteropts)
                 int i;
 
                 if (!mountTable) {
-                        bb_error_msg("no %s", bb_path_mtab_file);
+                        bb_perror_msg(bb_path_mtab_file);
                         goto ret;
                 }
 
                 // Add vfs string flags
-
                 for (i = 0; mount_options[i] != MS_REMOUNT; i++) {
                         if (mount_options[i] > 0 && (mount_options[i] & vfsflags))
                                 append_mount_options(&(mp->mnt_opts), option_str);
@@ -509,24 +563,28 @@ static int mount_it_now(struct mntent *mp, long vfsflags, char *filteropts)
                 }
 
                 // Remove trailing / (if any) from directory we mounted on
-
                 i = strlen(mp->mnt_dir) - 1;
-                if (i > 0 && mp->mnt_dir[i] == '/') mp->mnt_dir[i] = '\0';
+                while (i > 0 && mp->mnt_dir[i] == '/')
+                        mp->mnt_dir[i] = '\0';
 
                 // Convert to canonical pathnames as needed
-
                 mp->mnt_dir = bb_simplify_path(mp->mnt_dir);
-                fsname = 0;
+                fsname = NULL;
                 if (!mp->mnt_type || !*mp->mnt_type) { // bind mount
                         mp->mnt_fsname = fsname = bb_simplify_path(mp->mnt_fsname);
                         mp->mnt_type = (char*)"bind";
                 }
                 mp->mnt_freq = mp->mnt_passno = 0;
 
-                // Write and close.
-
-                addmntent(mountTable, mp);
+                // Write and close
+#if ENABLE_FEATURE_MTAB_SUPPORT
+                if (vfsflags & MS_MOVE)
+                        update_mtab_entry_on_move(mp);
+                else
+#endif
+                        addmntent(mountTable, mp);
                 endmntent(mountTable);
+
                 if (ENABLE_FEATURE_CLEAN_UP) {
                         free(mp->mnt_dir);
                         free(fsname);