[PATCH for-4.5] tools/pygrub: Fix TOCTOU race introduced by c/s 63dcc68

[Andrew Cooper <andrew.cooper3@citrix.com>]

In addition, use os.makedirs() which will also create intermediate directories
if they don't exist.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
CC: Ian Campbell <Ian.Campbell@citrix.com>
CC: Ian Jackson <Ian.Jackson@eu.citrix.com>
CC: Wei Liu <wei.liu2@citrix.com>
CC: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
CC: Olaf Hering <olaf@aepfle.de>
---
 tools/pygrub/src/pygrub |   12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/tools/pygrub/src/pygrub b/tools/pygrub/src/pygrub
index 1ae34a2..37dde32 100644
--- a/tools/pygrub/src/pygrub
+++ b/tools/pygrub/src/pygrub
@@ -13,7 +13,7 @@
 # Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 #
 
-import os, sys, string, struct, tempfile, re, traceback, stat
+import os, sys, string, struct, tempfile, re, traceback, stat, errno
 import copy
 import logging
 import platform
@@ -846,8 +846,14 @@ if __name__ == "__main__":
     if debug:
 	logging.basicConfig(level=logging.DEBUG)
 
-    if not os.path.isdir(output_directory):
-        os.mkdir(output_directory, 0700)
+
+    try:
+        os.makedirs(output_directory, 0700)
+    except OSError,e:
+        if (e.errno == errno.EEXIST) and os.path.isdir(output_directory):
+            pass
+        else:
+            raise
 
     if output is None or output == "-":
         fd = sys.stdout.fileno()
-- 
1.7.10.4