libfstools: move mount points when switching to JFFS2

[project/fstools.git] / libfstools / overlay.c

diff --git a/libfstools/overlay.c b/libfstools/overlay.c
index a41364c..ebc43f7 100644 (file)
--- a/libfstools/overlay.c
+++ b/libfstools/overlay.c
@@ -112,6 +112,24 @@ foreachdir(const char *dir, int (*cb)(const char*))
        cb(dir);
 }
 
+static void foreach_mount(int (*cb)(const char *, const char *))
+{
+       FILE *fp = fopen("/proc/mounts", "r");
+       static char line[256];
+
+       if (!fp)
+               return;
+
+       while (fgets(line, sizeof(line), fp)) {
+               char device[32], mount_point[32];
+
+               if (sscanf(line, "%31s %31s %*s %*s %*u %*u", device, mount_point) == 2)
+                       cb(device, mount_point);
+       }
+
+       fclose(fp);
+}
+
 void
 overlay_delete(const char *dir, bool _keep_sysupgrade)
 {
@@ -135,6 +153,19 @@ overlay_mount(struct volume *v, char *fs)
        return 0;
 }
 
+/**
+ * move_mount - move mount point to the new root
+ */
+static int move_mount(const char *device, const char *mount_point)
+{
+       static const char *prefix = "/tmp/root/";
+
+       if (strncmp(mount_point, prefix, strlen(prefix)))
+               return 0;
+
+       return mount_move(prefix, "/", mount_point + strlen(prefix));
+}
+
 static int
 switch2jffs(struct volume *v)
 {
@@ -174,7 +205,20 @@ switch2jffs(struct volume *v)
                return -1;
        }
 
-       return fopivot("/overlay", "/rom");
+       ret = fopivot("/overlay", "/rom");
+
+       /*
+        * Besides copying overlay data from "tmpfs" to "jffs2" we should also
+        * move mount points that user could create during JFFS2 formatting.
+        * This has to happen after fopivot call because:
+        * 1) It's trivial to find mount points to move then (/tmp/root/...).
+        * 2) We can't do that earlier using /rom/overlay/upper/ as overlay(fs)
+        *    doesn't support mounts. Mounting to upper dir don't make overlay
+        *    /propagate/ files to the target dir.
+        */
+       foreach_mount(move_mount);
+
+       return ret;
 }
 
 int