wic: using indirect string to connect images

index 0643780..311737a 100644
@@ -60,23 +60,6 @@ def verify_build_env():
     return True
 
 
-def find_bitbake_env_lines(image_name):
-    """
-    If image_name is empty, plugins might still be able to use the
-    environment, so set it regardless.
-    """
-    if image_name:
-        bitbake_env_cmd = "bitbake -e %s" % image_name
-    else:
-        bitbake_env_cmd = "bitbake -e"
-    rc, bitbake_env_lines = exec_cmd(bitbake_env_cmd)
-    if rc != 0:
-        print "Couldn't get '%s' output." % bitbake_env_cmd
-        return None
-
-    return bitbake_env_lines
-
-
 def find_artifacts(image_name):
     """
     Gather the build artifacts for the current image (the image_name

index 7ad3aa9..5436a0a 100644
@@ -126,6 +126,22 @@ def set_bitbake_env_lines(bitbake_env_lines):
 def get_bitbake_env_lines():
     return __bitbake_env_lines
 
+def find_bitbake_env_lines(image_name):
+    """
+    If image_name is empty, plugins might still be able to use the
+    environment, so set it regardless.
+    """
+    if image_name:
+        bitbake_env_cmd = "bitbake -e %s" % image_name
+    else:
+        bitbake_env_cmd = "bitbake -e"
+    rc, bitbake_env_lines = exec_cmd(bitbake_env_cmd)
+    if rc != 0:
+        print "Couldn't get '%s' output." % bitbake_env_cmd
+        return None
+
+    return bitbake_env_lines
+
 def get_line_val(line, key):
     """
     Extract the value from the VAR="val" string

index 5436a0a..16c250a 100644
@@ -142,6 +142,20 @@ def find_bitbake_env_lines(image_name):
 
     return bitbake_env_lines
 
+def find_artifact(bitbake_env_lines, variable):
+    """
+    Gather the build artifact for the current image (the image_name
+    e.g. core-image-minimal) for the current MACHINE set in local.conf
+    """
+    retval = ""
+
+    for line in bitbake_env_lines.split('\n'):
+        if (get_line_val(line, variable)):
+            retval = get_line_val(line, variable)
+            break
+
+    return retval
+
 def get_line_val(line, key):
     """
     Extract the value from the VAR="val" string

index 75999e0..a4d4547 100644
@@ -43,6 +43,25 @@ from mic.imager.direct import DirectImageCreator
 class RootfsPlugin(SourcePlugin):
     name = 'rootfs'
 
+    @staticmethod
+    def __get_rootfs_dir(rootfs_dir):
+        if os.path.isdir(rootfs_dir):
+            return rootfs_dir
+
+        bitbake_env_lines = find_bitbake_env_lines(rootfs_dir)
+        if not bitbake_env_lines:
+            msg = "Couldn't get bitbake environment, exiting."
+            msger.error(msg)
+
+        image_rootfs_dir = find_artifact(bitbake_env_lines, "IMAGE_ROOTFS")
+        if not os.path.isdir(image_rootfs_dir):
+            msg = "No valid artifact IMAGE_ROOTFS from image named"
+            msg += " %s has been found at %s, exiting.\n" % \
+                (rootfs_dir, image_rootfs_dir)
+            msger.error(msg)
+
+        return image_rootfs_dir
+
     @classmethod
     def do_prepare_partition(self, part, cr, cr_workdir, oe_builddir, bootimg_dir,
                              kernel_dir, krootfs_dir, native_sysroot):

@@ -59,13 +78,15 @@ class RootfsPlugin(SourcePlugin):
         else:
             if part.rootfs in krootfs_dir:
                 rootfs_dir = krootfs_dir[part.rootfs]
-            elif os.path.isdir(part.rootfs):
+            elif part.rootfs:
                 rootfs_dir = part.rootfs
             else:
                 msg = "Couldn't find --rootfs-dir=%s connection"
                 msg += " or it is not a valid path, exiting"
                 msger.error(msg % part.rootfs)
 
-        part.set_rootfs(rootfs_dir)
-        part.prepare_rootfs(cr_workdir, oe_builddir, rootfs_dir, native_sysroot)
+        real_rootfs_dir = self.__get_rootfs_dir(rootfs_dir)
+
+        part.set_rootfs(real_rootfs_dir)
+        part.prepare_rootfs(cr_workdir, oe_builddir, real_rootfs_dir, native_sysroot)