wic/plugins/rootfs: Fix permissions when splitting rootfs folders across partitions

This patches makes locating the file database containing the file and
folder usernames and permissions more reliable.
In addition to locating it relative to the partition directory, we also
try to locate it relative to the IMAGE_ROOTFS.

Prior to this patch, the database was not found when using
--rootfs-dir=${IMAGE_ROOTFS}/<x> in the WIC script, leading to erronous file
permissions and ownership.

(From OE-Core rev: d730fbc26993c2187c908e57a465536a508e9ee2)

Signed-off-by: Felix Moessbauer <felix.moessbauer@siemens.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit 09e18ee246da8b56f446c4db548fb9c7e895142b)
Signed-off-by: Anuj Mittal <anuj.mittal@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

scripts/lib/wic/plugins/source/rootfs.py

@@ -50,7 +50,7 @@ class RootfsPlugin(SourcePlugin):
 
     @staticmethod
     def __get_rootfs_dir(rootfs_dir):
-        if os.path.isdir(rootfs_dir):
+        if rootfs_dir and os.path.isdir(rootfs_dir):
             return os.path.realpath(rootfs_dir)
 
         image_rootfs_dir = get_bitbake_var("IMAGE_ROOTFS", rootfs_dir)
@@ -96,6 +96,9 @@ class RootfsPlugin(SourcePlugin):
         part.rootfs_dir = cls.__get_rootfs_dir(rootfs_dir)
         part.has_fstab = os.path.exists(os.path.join(part.rootfs_dir, "etc/fstab"))
         pseudo_dir = os.path.join(part.rootfs_dir, "../pseudo")
+        if not os.path.lexists(pseudo_dir):
+            pseudo_dir = os.path.join(cls.__get_rootfs_dir(None), '../pseudo')
+
         if not os.path.lexists(pseudo_dir):
             logger.warn("%s folder does not exist. "
                         "Usernames and permissions will be invalid " % pseudo_dir)