[libvirt] [PATCH] Tweak EOF handling of streams

Daniel P. Berrange berrange at redhat.com
Tue Apr 9 14:00:25 UTC 2013


On Tue, Apr 09, 2013 at 07:57:11AM -0600, Eric Blake wrote:
> On 04/09/2013 06:25 AM, Daniel P. Berrange wrote:
> > From: "Daniel P. Berrange" <berrange at redhat.com>
> > 
> > Typically when you get EOF on a stream, poll will return
> > POLLIN|POLLHUP at the same time. Thus when we deal with
> > stream reads, if we see EOF during the read, we can then
> > clear the VIR_STREAM_EVENT_HANGUP & VIR_STREAM_EVENT_ERROR
> > event bits.
> > 
> > Signed-off-by: Daniel P. Berrange <berrange at redhat.com>
> > ---
> >  daemon/stream.c | 8 ++++++++
> >  1 file changed, 8 insertions(+)
> > 
> > diff --git a/daemon/stream.c b/daemon/stream.c
> > index 4df1145..0fb5c85 100644
> > --- a/daemon/stream.c
> > +++ b/daemon/stream.c
> > @@ -148,6 +148,14 @@ daemonStreamEvent(virStreamPtr st, int events, void *opaque)
> >              virNetServerClientClose(client);
> >              goto cleanup;
> >          }
> > +        /* If we detected EOF during read processing,
> > +         * then clear hangup/error conditions, since
> > +         * we want the client to see the EOF message
> > +         * we just sent them
> > +         */
> > +        if (stream->recvEOF)
> > +            events = events & ~(VIR_STREAM_EVENT_HANGUP |
> > +                                VIR_STREAM_EVENT_ERROR);
> 
> Ignoring HANGUP makes sense, but do we really want to suppress errors?

You get EVENT_ERROR if you are polling for writability and HUP occurs,
so it needs to be treated in the same way as HANGUP.


Daniel
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