[Qemu-devel] [PATCH v6 1/7] qemu.py: use poll() instead of 'returncode'

[Amador Pahim]

The 'returncode' Popen attribute is not guaranteed to be updated. It
actually depends on a call to either poll(), wait() or communicate().

On the other hand, poll() will: "Check if child process has terminated.
Set and return returncode attribute."

Let's use the poll() to check whether the process is running and also
to get the updated process exit code, when the process is finished.

Signed-off-by: Amador Pahim <address@hidden>
Reviewed-by: Fam Zheng <address@hidden>
Reviewed-by: Stefan Hajnoczi <address@hidden>
---
 scripts/qemu.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/scripts/qemu.py b/scripts/qemu.py
index 880e3e8219..2f1984c93c 100644
--- a/scripts/qemu.py
+++ b/scripts/qemu.py
@@ -86,12 +86,12 @@ 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:
             return None
-        return self._popen.returncode
+        return self._popen.poll()
 
     def get_pid(self):
         if not self.is_running():
-- 
2.13.3