Re: [Qemu-devel] [PATCH 2/4] qemu-iotests: Add VM method qtest_cmd() to iotests.py

[Stefan Hajnoczi]

On Wed, Jan 29, 2014 at 04:40:41PM +0800, Fam Zheng wrote:
> This will allow test case to run command in qtest protocol. It's
> write-only for now.
> 
> Signed-off-by: Fam Zheng <address@hidden>
> ---
>  tests/qemu-iotests/iotests.py | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/tests/qemu-iotests/iotests.py b/tests/qemu-iotests/iotests.py
> index e4fa9af..ca79d09 100644
> --- a/tests/qemu-iotests/iotests.py
> +++ b/tests/qemu-iotests/iotests.py
> @@ -153,13 +153,16 @@ class VM(object):
>                               stderr=sys.stderr)
>          return p.wait()
>  
> +    def qtest_cmd(self, cmd):
> +        self._popen.stdin.write(cmd + "\n")
> +
>      def launch(self):
>          '''Launch the VM and establish a QMP connection'''
> -        devnull = open('/dev/null', 'rb')
>          qemulog = open(self._qemu_log_path, 'wb')
>          try:
>              self._qmp = qmp.QEMUMonitorProtocol(self._monitor_path, 
> server=True)
> -            self._popen = subprocess.Popen(self._args, stdin=devnull, 
> stdout=qemulog,
> +            self._popen = subprocess.Popen(self._args, stdin=subprocess.PIPE,
> +                                           stdout=qemulog,
>                                             stderr=subprocess.STDOUT)

Commit 0fd05e8dd1ee7ae143fba3d6bcc6abe3fbeaeb34 ("qemu-iotests: start
vms in qtest mode") put qtest on stdio.  I think that was a mistake and
it should be fixed if you want to drive qtest.

Let's not mix qtest output with QEMU stderr.  If you need to drive
qtest, put it on a dedicated UNIX domain socket
(just like QMP).

Implement the qtest protocol as documented in qtest.c:

 * Line based protocol, request/response based.  Server can send async messages
 * so clients should always handle many async messages before the response
 * comes in.

Stefan