[PATCH] rootfs.py: support absolute paths in IMAGE_DEVICE_TABLES

[Andre McCurdy <armccurdy@gmail.com>]

Paths relative to BBPATH are fine if device table files are always
static and contained somewhere within a meta layer. However if device
tables are created dynamically, they will be located somewhere within
${TMPDIR} and most conveniently referenced via an absolute path.

The legacy IMAGE_DEVICE_TABLE variable supported an absolute path,
therefore make IMAGE_DEVICE_TABLES support absolute paths too, to
avoid users who need dynamic device table files being dependent on
the legacy variable.

Signed-off-by: Andre McCurdy <armccurdy@gmail.com>
---
 meta/lib/oe/rootfs.py | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/meta/lib/oe/rootfs.py b/meta/lib/oe/rootfs.py
index a348b97..32cce64 100644
--- a/meta/lib/oe/rootfs.py
+++ b/meta/lib/oe/rootfs.py
@@ -352,8 +352,8 @@ class Rootfs(object, metaclass=ABCMeta):
     """
     Create devfs:
     * IMAGE_DEVICE_TABLE is the old name to an absolute path to a device table file
-    * IMAGE_DEVICE_TABLES is a new name for a file, or list of files, seached
-      for in the BBPATH
+    * IMAGE_DEVICE_TABLES is the new name for a file, or list of files, which may be
+      either absolute paths or paths relative to BBPATH.
     If neither are specified then the default name of files/device_table-minimal.txt
     is searched for in the BBPATH (same as the old version.)
     """
@@ -367,7 +367,10 @@ class Rootfs(object, metaclass=ABCMeta):
             if devtables is None:
                 devtables = 'files/device_table-minimal.txt'
             for devtable in devtables.split():
-                devtable_list.append("%s" % bb.utils.which(self.d.getVar('BBPATH', True), devtable))
+                if os.path.isabs(devtable):
+                    devtable_list.append(devtable)
+                else:
+                    devtable_list.append("%s" % bb.utils.which(self.d.getVar('BBPATH', True), devtable))
 
         for devtable in devtable_list:
             self._exec_shell_cmd(["makedevs", "-r",
-- 
1.9.1