[Spice-devel] [PATCH spice-gtk] spice-channel: return if has_error is TRUE in spice_channel_write_msg

[Jakub Janku]

Hi,

On Thu, Jun 27, 2019 at 10:10 AM Frediano Ziglio <fziglio at redhat.com> wrote:
>
> >
> > Avoid linearizing if the message isn't written out anyway
>
> "linearizing" ? What do you mean about that?
> Looking at definitions it seems not correct to me.

I was simply referring to the spice_marshaller_linearize() call.
>
> > (spice_channel_flush_wire checks() this condition as well).
> >
> > This also silences the following error:
> >
> >     (spicy:32087): GSpice-CRITICAL **: 16:22:03.147:
> >     spice_session_get_read_only: assertion 'SPICE_IS_SESSION(self)' failed
> >
> > that can be seen if the channel gets disconnected
> > by the session while having non-empty write queue.
> >
> > spice_session_channel_destroy() sets channel->priv->session to NULL,
> > but spice_channel_write_msg() subsequently attempts to call
> > spice_session_get_read_only() with NULL pointer.
> >
>
> Minor: this is the explanation why the error on the previous
> paragraph should not be treated like an error, I think it should
> be the same paragraphs.

Makes sense.
>
> OT: maybe channel session should never be NULL?

It indeed does seem weird that
g_clear_object(&channel->priv->session); is called when the
"spice-session" property of the channel is G_PARAM_CONSTRUCT_ONLY --
with this flag, I would expect the property to not change after the
construction.

Spice session waits for the channel destruction anyway
(channel_finally_destroyed callback), so it should be imho fine that
the channel holds a reference to the session while it is being
destroyed. So I think we could remove that
g_clear_object(&channel->priv->session); call in
spice_session_channel_destroy().
>
> > Signed-off-by: Jakub Janků <jjanku at redhat.com>
> > ---
> >  src/spice-channel.c | 5 +++++
> >  1 file changed, 5 insertions(+)
> >
> > diff --git a/src/spice-channel.c b/src/spice-channel.c
> > index 61de177..aa80edf 100644
> > --- a/src/spice-channel.c
> > +++ b/src/spice-channel.c
> > @@ -897,6 +897,11 @@ static void spice_channel_write_msg(SpiceChannel
> > *channel, SpiceMsgOut *out)
> >      g_return_if_fail(out != NULL);
> >      g_return_if_fail(channel == out->channel);
> >
> > +    if (channel->priv->has_error) {
> > +        spice_msg_out_unref(out);
> > +        return;
> > +    }
> > +
> >      if (out->ro_check &&
> >          spice_channel_get_read_only(channel)) {
> >          g_warning("Try to send message while read-only. Please report a
> >          bug.");
>
> Frediano