From 10766995ec5914247c21694062337c22e83e1dff Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?P=C3=A1draig=20Brady?= <pbrady@redhat.com>
Date: Mon, 17 Sep 2012 13:19:18 +0100
Subject: [PATCH] fix cleanup_file_locks with restricted permissions

SELinux was seen to disallow kill(pid, 0).
Therefore ensure that the pid is determined
to be still running if we get EPERM.

Fixes bug: 1051924
Change-Id: Ib84e2fc460066ee03070b9bda15732cce573ccf3
---
 nova/utils.py | 20 +++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/nova/utils.py b/nova/utils.py
index 01a52b52ae3f..6535b06468a1 100644
--- a/nova/utils.py
+++ b/nova/utils.py
@@ -21,6 +21,7 @@
 
 import contextlib
 import datetime
+import errno
 import functools
 import hashlib
 import inspect
@@ -1000,11 +1001,12 @@ def cleanup_file_locks():
                   {'filename': filename, 'pid': pid})
         try:
             os.kill(int(pid), 0)
-        except OSError, e:
-            # PID wasn't found
-            delete_if_exists(os.path.join(FLAGS.lock_path, filename))
-            LOG.debug(_('Cleaned sentinel %(filename)s for pid %(pid)s') %
-                      {'filename': filename, 'pid': pid})
+        except OSError as e:
+            if e.errno == errno.ESRCH:
+                # PID wasn't found
+                delete_if_exists(os.path.join(FLAGS.lock_path, filename))
+                LOG.debug(_('Cleaned sentinel %(filename)s for pid %(pid)s') %
+                          {'filename': filename, 'pid': pid})
 
     # cleanup lock files
     for filename in files:
@@ -1013,8 +1015,8 @@ def cleanup_file_locks():
             continue
         try:
             stat_info = os.stat(os.path.join(FLAGS.lock_path, filename))
-        except OSError as (errno, strerror):
-            if errno == 2:  # doesn't exist
+        except OSError as e:
+            if e.errno == errno.ENOENT:
                 continue
             else:
                 raise
@@ -1033,8 +1035,8 @@ def delete_if_exists(pathname):
 
     try:
         os.unlink(pathname)
-    except OSError as (errno, strerror):
-        if errno == 2:  # doesn't exist
+    except OSError as e:
+        if e.errno == errno.ENOENT:
             return
         else:
             raise