Re: [PATCH V5 21/23] tests/qtest: assert qmp_ready

[Peter Xu <peterx@redhat.com>]

On Tue, Dec 24, 2024 at 08:17:06AM -0800, Steve Sistare wrote:
> Set qmp_ready when the handshake is complete, and assert it when we
> communicate with the monitor.
> 
> Suggested-by: Peter Xu <peterx@redhat.com>
> Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
> ---
>  tests/qtest/libqtest.c | 20 +++++++++++++++++---
>  1 file changed, 17 insertions(+), 3 deletions(-)
> 
> diff --git a/tests/qtest/libqtest.c b/tests/qtest/libqtest.c
> index 2f44d3c..43ee92f 100644
> --- a/tests/qtest/libqtest.c
> +++ b/tests/qtest/libqtest.c
> @@ -77,6 +77,7 @@ struct QTestState
>      int qmp_fd;
>      int sock;
>      int qmpsock;
> +    bool qmp_ready;
>      pid_t qemu_pid;  /* our child QEMU process */
>      int wstatus;
>  #ifdef _WIN32
> @@ -552,14 +553,23 @@ void qtest_connect(QTestState *s)
>  
>  QTestState *qtest_init_without_qmp_handshake(const char *extra_args)
>  {
> -    return qtest_init_internal(qtest_qemu_binary(NULL), extra_args, true);
> +    QTestState *s = qtest_init_internal(qtest_qemu_binary(NULL), extra_args,
> +                                        true);
> +
> +    /* Not really ready, but callers need it to test handshakes */
> +    s->qmp_ready = true;

This is a bit ugly.  The patch defined qmp_ready to be "after qmp
handshake" so here it needs to be ugly.  However IIUC what we want to
protect against is trying to read() the qmp before connection (while
handshake may or may not happen).

So I suppose if we use that definition instead (could rename it to
qmp_connected if that's clearer), then set it to TRUE in qtest_connect()
should work for all cases, meanwhile provide the same guard for things like
cpr tests.

> +    return s;
>  }
>  
>  void qtest_qmp_handshake(QTestState *s)
>  {
> +    g_autoptr(QDict) greeting = NULL;
> +
> +    /* Set ready first because functions called below assert it */
> +    s->qmp_ready = true;
> +
>      /* Read the QMP greeting and then do the handshake */
> -    QDict *greeting = qtest_qmp_receive(s);
> -    qobject_unref(greeting);
> +    greeting = qtest_qmp_receive(s);
>      qobject_unref(qtest_qmp(s, "{ 'execute': 'qmp_capabilities' }"));
>  }
>  
> @@ -786,6 +796,7 @@ QDict *qtest_qmp_receive(QTestState *s)
>  
>  QDict *qtest_qmp_receive_dict(QTestState *s)
>  {
> +    g_assert(s->qmp_ready);
>      return qmp_fd_receive(s->qmp_fd);
>  }
>  
> @@ -813,12 +824,14 @@ int qtest_socket_server(const char *socket_path)
>  void qtest_qmp_vsend_fds(QTestState *s, int *fds, size_t fds_num,
>                           const char *fmt, va_list ap)
>  {
> +    g_assert(s->qmp_ready);
>      qmp_fd_vsend_fds(s->qmp_fd, fds, fds_num, fmt, ap);
>  }
>  #endif
>  
>  void qtest_qmp_vsend(QTestState *s, const char *fmt, va_list ap)
>  {
> +    g_assert(s->qmp_ready);
>      qmp_fd_vsend(s->qmp_fd, fmt, ap);
>  }
>  
> @@ -879,6 +892,7 @@ void qtest_qmp_send_raw(QTestState *s, const char *fmt, ...)
>  {
>      va_list ap;
>  
> +    g_assert(s->qmp_ready);
>      va_start(ap, fmt);
>      qmp_fd_vsend_raw(s->qmp_fd, fmt, ap);
>      va_end(ap);
> -- 
> 1.8.3.1
> 

-- 
Peter Xu