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>

diff --git a/util-linux/mount.c b/util-linux/mount.c
index 0baa74c7c53544bef9208d9856e2eb36c8370e2b..0127f1958a8db15e491b62456708b2ecf749444e 100644 (file)
--- 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);