[Qemu-devel] [PATCH v3 1/3] qemu.py: fix is_running()

[Amador Pahim <apahim@redhat.com>]

Current implementation is broken. It does not really test if the child
process is running.

The Popen.returncode will only be set after by a poll(), wait() or
communicate(). If the Popen fails to launch a VM, the Popen.returncode
will not turn to None by itself.

Instead of using Popen.returncode, let's use Popen.poll(), which
actually checks if child process has terminated.

Signed-off-by: Amador Pahim <apahim@redhat.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
---
 scripts/qemu.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/scripts/qemu.py b/scripts/qemu.py
index 880e3e8219..f0fade32bd 100644
--- a/scripts/qemu.py
+++ b/scripts/qemu.py
@@ -86,7 +86,7 @@ class QEMUMachine(object):
             raise
 
     def is_running(self):
-        return self._popen and (self._popen.returncode is None)
+        return self._popen and (self._popen.poll() is None)
 
     def exitcode(self):
         if self._popen is None:
-- 
2.13.3