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Re: [Qemu-devel] [PATCH v2 1/3] qemu.py: fix is_running()
From: |
Eduardo Habkost |
Subject: |
Re: [Qemu-devel] [PATCH v2 1/3] qemu.py: fix is_running() |
Date: |
Wed, 19 Jul 2017 15:34:47 -0300 |
User-agent: |
Mutt/1.8.0 (2017-02-23) |
On Wed, Jul 19, 2017 at 06:31:06PM +0200, Amador Pahim wrote:
> 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 <address@hidden>
I vaguely remember I had a version of that code using poll() and
it broke scripts for some reason. I will try to find out why, so
we can either fix the script or document the reason why poll()
isn't a good choice here.
> ---
> 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
>
--
Eduardo