xenapi plugins: Make sure subprocesses finish executing

Fixes bug 1286187

Neither execute_get_output() nor execute() would wait for the process to
fully finish executing. This could potentially create a race condition
where commands execute in a different order than intended.

Also, for execute() it could cause a process to never finish executing if
it generates enough output to block writing to the pipe.

Change-Id: I3404f4b3ca1cddeec2f3e7b393817a6ccc42bec7

1 files changed, 3 insertions, 3 deletions

diff --git a/plugins/xenserver/networking/etc/xensource/scripts/novalib.py b/plugins/xenserver/networking/etc/xensource/scripts/novalib.py
index 4785b63d71..17da30c7d7 100644
--- a/plugins/xenserver/networking/etc/xensource/scripts/novalib.py
+++ b/plugins/xenserver/networking/etc/xensource/scripts/novalib.py
@@ -26,13 +26,13 @@ def execute_get_output(*command):
     proc = subprocess.Popen(command, close_fds=True,
                             stdout=subprocess.PIPE, stderr=devnull)
     devnull.close()
-    return proc.stdout.read().strip()
+    stdout = proc.communicate()[0]
+    return stdout.strip()
 
 
 def execute(*command):
     """Execute without returning stdout."""
     devnull = open(os.devnull, 'w')
     command = map(str, command)
-    proc = subprocess.Popen(command, close_fds=True,
-                            stdout=subprocess.PIPE, stderr=devnull)
+    subprocess.call(command, close_fds=True, stdout=devnull, stderr=devnull)
     devnull.close()