resizefs: Prefix discovered devpath with '/dev/' when path does not exist

In some environments, like FreeBSD, gpart can return the device basename
instead of the full path. If this discovered devpath does not exist and
is missing the '/dev/' prefix, add that prefix in an attempt to find the
device.

2 files changed, 47 insertions, 8 deletions

diff --git a/cloudinit/config/cc_resizefs.py b/cloudinit/config/cc_resizefs.py
index 2edddd0c..076b9d5a 100644
--- a/cloudinit/config/cc_resizefs.py
+++ b/cloudinit/config/cc_resizefs.py
@@ -197,6 +197,13 @@ def maybe_get_writable_device_path(devpath, info, log):
     if devpath.startswith('gpt/'):
         log.debug('We have a gpt label - just go ahead')
         return devpath
+    # Alternatively, our device could simply be a name as returned by gpart,
+    # such as da0p3
+    if not devpath.startswith('/dev/') and not os.path.exists(devpath):
+        fulldevpath = '/dev/' + devpath.lstrip('/')
+        log.debug("'%s' doesn't appear to be a valid device path. Trying '%s'",
+                  devpath, fulldevpath)
+        devpath = fulldevpath
 
     try:
         statret = os.stat(devpath)
diff --git a/tests/unittests/test_handler/test_handler_resizefs.py b/tests/unittests/test_handler/test_handler_resizefs.py
index feca56c2..6ebacb1a 100644
--- a/tests/unittests/test_handler/test_handler_resizefs.py
+++ b/tests/unittests/test_handler/test_handler_resizefs.py
@@ -173,6 +173,38 @@ class TestResizefs(CiTestCase):
 
         self.assertEqual(('zpool', 'online', '-e', 'vmzroot', disk), ret)
 
+    @mock.patch('cloudinit.util.is_container', return_value=False)
+    @mock.patch('cloudinit.util.get_mount_info')
+    @mock.patch('cloudinit.util.get_device_info_from_zpool')
+    @mock.patch('cloudinit.util.parse_mount')
+    def test_handle_modern_zfsroot(self, mount_info, zpool_info, parse_mount,
+                                   is_container):
+        devpth = 'zroot/ROOT/default'
+        disk = 'da0p3'
+        fs_type = 'zfs'
+        mount_point = '/'
+
+        mount_info.return_value = (devpth, fs_type, mount_point)
+        zpool_info.return_value = disk
+        parse_mount.return_value = (devpth, fs_type, mount_point)
+
+        cfg = {'resize_rootfs': True}
+
+        def fake_stat(devpath):
+            if devpath == disk:
+                raise OSError("not here")
+            FakeStat = namedtuple(
+                'FakeStat', ['st_mode', 'st_size', 'st_mtime'])  # minimal stat
+            return FakeStat(25008, 0, 1)  # fake char block device
+
+        with mock.patch('cloudinit.config.cc_resizefs.do_resize') as dresize:
+            with mock.patch('cloudinit.config.cc_resizefs.os.stat') as m_stat:
+                m_stat.side_effect = fake_stat
+                handle('cc_resizefs', cfg, _cloud=None, log=LOG, args=[])
+
+        self.assertEqual(('zpool', 'online', '-e', 'zroot', '/dev/' + disk),
+                         dresize.call_args[0][0])
+
 
 class TestRootDevFromCmdline(CiTestCase):
 
@@ -246,39 +278,39 @@ class TestMaybeGetDevicePathAsWritableBlock(CiTestCase):
 
     def test_maybe_get_writable_device_path_does_not_exist(self):
         """When devpath does not exist, a warning is logged."""
-        info = 'dev=/I/dont/exist mnt_point=/ path=/dev/none'
+        info = 'dev=/dev/I/dont/exist mnt_point=/ path=/dev/none'
         devpath = wrap_and_call(
             'cloudinit.config.cc_resizefs.util',
             {'is_container': {'return_value': False}},
-            maybe_get_writable_device_path, '/I/dont/exist', info, LOG)
+            maybe_get_writable_device_path, '/dev/I/dont/exist', info, LOG)
         self.assertIsNone(devpath)
         self.assertIn(
-            "WARNING: Device '/I/dont/exist' did not exist."
+            "WARNING: Device '/dev/I/dont/exist' did not exist."
             ' cannot resize: %s' % info,
             self.logs.getvalue())
 
     def test_maybe_get_writable_device_path_does_not_exist_in_container(self):
         """When devpath does not exist in a container, log a debug message."""
-        info = 'dev=/I/dont/exist mnt_point=/ path=/dev/none'
+        info = 'dev=/dev/I/dont/exist mnt_point=/ path=/dev/none'
         devpath = wrap_and_call(
             'cloudinit.config.cc_resizefs.util',
             {'is_container': {'return_value': True}},
-            maybe_get_writable_device_path, '/I/dont/exist', info, LOG)
+            maybe_get_writable_device_path, '/dev/I/dont/exist', info, LOG)
         self.assertIsNone(devpath)
         self.assertIn(
-            "DEBUG: Device '/I/dont/exist' did not exist in container."
+            "DEBUG: Device '/dev/I/dont/exist' did not exist in container."
             ' cannot resize: %s' % info,
             self.logs.getvalue())
 
     def test_maybe_get_writable_device_path_raises_oserror(self):
         """When unexpected OSError is raises by os.stat it is reraised."""
-        info = 'dev=/I/dont/exist mnt_point=/ path=/dev/none'
+        info = 'dev=/dev/I/dont/exist mnt_point=/ path=/dev/none'
         with self.assertRaises(OSError) as context_manager:
             wrap_and_call(
                 'cloudinit.config.cc_resizefs',
                 {'util.is_container': {'return_value': True},
                  'os.stat': {'side_effect': OSError('Something unexpected')}},
-                maybe_get_writable_device_path, '/I/dont/exist', info, LOG)
+                maybe_get_writable_device_path, '/dev/I/dont/exist', info, LOG)
         self.assertEqual(
             'Something unexpected', str(context_manager.exception))