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 to get
the updated process exit code, when the process is finished.

Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Amador Pahim <apahim@redhat.com>
---
 scripts/qemu.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/scripts/qemu.py b/scripts/qemu.py
index 7bd10b1a1d..d3824a7a0b 100644
--- a/scripts/qemu.py
+++ b/scripts/qemu.py
@@ -149,12 +149,12 @@ class QEMUMachine(object):
             raise
 
     def is_running(self):
-        return self._popen is not None and self._popen.returncode is None
+        return self._popen is not None 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():
-- 
2.13.6

On Tue, Nov 14, 2017 at 11:22:43AM +0100, Amador Pahim wrote:
> 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 to get
> the updated process exit code, when the process is finished.
> 
> Reviewed-by: Fam Zheng <famz@redhat.com>
> Signed-off-by: Amador Pahim <apahim@redhat.com>
> ---
>  scripts/qemu.py | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/scripts/qemu.py b/scripts/qemu.py
> index 7bd10b1a1d..d3824a7a0b 100644
> --- a/scripts/qemu.py
> +++ b/scripts/qemu.py
> @@ -149,12 +149,12 @@ class QEMUMachine(object):
>              raise
>  
>      def is_running(self):
> -        return self._popen is not None and self._popen.returncode is None
> +        return self._popen is not None and self._popen.poll() is None

This should be safe now, after patch 4/8.

Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>

-- 
Eduardo