DataSourceConfigDrive: consider CD rom as valid config-drive source.

previously, there was an attempt in the config drive source to limit
the source device to a "full block device" rather than a partition.

This was done by a simplistic approach of checking that the last 
character of the name was not a number.  That was filtering out
CD-rom devices (sr0).

Now, we have a bit more sophisticated approach to that same problem.
We filter out block devices that have a 'partition' entry in
/sys/class/block/DEVICE_NAME/partition .

LP: #1100545

4 files changed, 22 insertions, 6 deletions

diff --git a/ChangeLog b/ChangeLog
index 544032a2..f076a27f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -20,6 +20,8 @@
    all accounts would be locked unless 'system' was given (LP: #1096423).
  - Allow 'sr0' (or sr[0-9]) to be specified without /dev/ as a source for
    mounts. [Vlastimil Holer]
+ - allow config-drive-data to come from a CD device by more correctly
+   filtering out partitions.  (LP: #1100545)
 0.7.1:
  - sysvinit: fix missing dependency in cloud-init job for RHEL 5.6 
  - config-drive: map hostname to local-hostname (LP: #1061964)
diff --git a/cloudinit/sources/DataSourceConfigDrive.py b/cloudinit/sources/DataSourceConfigDrive.py
index c7826851..ec016a1d 100644
--- a/cloudinit/sources/DataSourceConfigDrive.py
+++ b/cloudinit/sources/DataSourceConfigDrive.py
@@ -270,7 +270,7 @@ def find_candidate_devs():
     combined = (by_label + [d for d in by_fstype if d not in by_label])
 
     # We are looking for block device (sda, not sda1), ignore partitions
-    combined = [d for d in combined if d[-1] not in "0123456789"]
+    combined = [d for d in combined if not util.is_partition(d)]
 
     return combined
 
diff --git a/cloudinit/util.py b/cloudinit/util.py
index ab918433..c0ea8d91 100644
--- a/cloudinit/util.py
+++ b/cloudinit/util.py
@@ -1553,3 +1553,10 @@ def keyval_str_to_dict(kvstring):
             val = True
         ret[key] = val
     return ret
+
+
+def is_partition(device):
+    if device.startswith("/dev/"):
+        device = device[5:]
+
+    return os.path.isfile("/sys/class/block/%s/partition" % device)
diff --git a/tests/unittests/test_datasource/test_configdrive.py b/tests/unittests/test_datasource/test_configdrive.py
index 6751a679..930086db 100644
--- a/tests/unittests/test_datasource/test_configdrive.py
+++ b/tests/unittests/test_datasource/test_configdrive.py
@@ -257,19 +257,25 @@ class TestConfigDriveDataSource(MockerTestCase):
                           ds.read_config_drive_dir, my_d)
 
     def test_find_candidates(self):
-        devs_with_answers = {
-            "TYPE=vfat": [],
-            "TYPE=iso9660": ["/dev/vdb"],
-            "LABEL=config-2": ["/dev/vdb"],
-        }
+        devs_with_answers = {}
 
         def my_devs_with(criteria):
             return devs_with_answers[criteria]
 
+        def my_is_partition(dev):
+            return dev[-1] in "0123456789" and not dev.startswith("sr")
+
         try:
             orig_find_devs_with = util.find_devs_with
             util.find_devs_with = my_devs_with
 
+            orig_is_partition = util.is_partition
+            util.is_partition = my_is_partition
+
+            devs_with_answers = {"TYPE=vfat": [],
+                "TYPE=iso9660": ["/dev/vdb"],
+                "LABEL=config-2": ["/dev/vdb"],
+            }
             self.assertEqual(["/dev/vdb"], ds.find_candidate_devs())
 
             # add a vfat item
@@ -285,6 +291,7 @@ class TestConfigDriveDataSource(MockerTestCase):
 
         finally:
             util.find_devs_with = orig_find_devs_with
+            util.is_partition = orig_is_partition
 
     def test_pubkeys_v2(self):
         """Verify that public-keys work in config-drive-v2."""