[Qemu-devel] [PATCH v2] io: fix handling of EOF / error conditions in websock GSource

[Qemu-devel] [PATCH v2] io: fix handling of EOF / error conditions in websock GSource

[Daniel P. Berrangé]

We were never reporting the G_IO_HUP event when an end of file was hit
on the websocket channel.

We also didn't report G_IO_ERR when we hit a fatal error processing the
websocket protocol.

The latter in particular meant that the chardev code would not notice
when an eof/error was encountered on the websocket channel, unless the
guest OS happened to trigger a write operation.

This meant that once the first client had quit, the chardev would never
listen to accept a new client.

Fixes launchpad bug 1816819
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
---

Changed in v2:
 - Fix typo
 - Remove use of G_IO_IN at same time as HUP/ERR since. It is
   not required since the websock source doesn't do a real
   poll itself.

 io/channel-websock.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/io/channel-websock.c b/io/channel-websock.c
index dc43dc6bb9..77d30f0e4a 100644
--- a/io/channel-websock.c
+++ b/io/channel-websock.c
@@ -1225,12 +1225,18 @@ qio_channel_websock_source_check(GSource *source)
     QIOChannelWebsockSource *wsource = (QIOChannelWebsockSource *)source;
     GIOCondition cond = 0;
 
-    if (wsource->wioc->rawinput.offset || wsource->wioc->io_eof) {
+    if (wsource->wioc->rawinput.offset) {
         cond |= G_IO_IN;
     }
     if (wsource->wioc->encoutput.offset < QIO_CHANNEL_WEBSOCK_MAX_BUFFER) {
         cond |= G_IO_OUT;
     }
+    if (wsource->wioc->io_eof) {
+        cond |= G_IO_HUP;
+    }
+    if (wsource->wioc->io_err) {
+        cond |= G_IO_ERR;
+    }
 
     return cond & wsource->condition;
 }
-- 
2.20.1

Re: [Qemu-devel] [PATCH v2] io: fix handling of EOF / error conditions in websock GSource

[Philippe Mathieu-Daudé]

On Tue, Mar 19, 2019 at 12:24 PM Daniel P. Berrangé <berrange@redhat.com> wrote:
>
> ping
>
> On Thu, Mar 07, 2019 at 04:58:24PM +0000, Daniel P. Berrangé wrote:
> > We were never reporting the G_IO_HUP event when an end of file was hit
> > on the websocket channel.
> >
> > We also didn't report G_IO_ERR when we hit a fatal error processing the
> > websocket protocol.
> >
> > The latter in particular meant that the chardev code would not notice
> > when an eof/error was encountered on the websocket channel, unless the
> > guest OS happened to trigger a write operation.
> >
> > This meant that once the first client had quit, the chardev would never
> > listen to accept a new client.
> >
> > Fixes launchpad bug 1816819
> > Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
> > ---
> >
> > Changed in v2:
> >  - Fix typo
> >  - Remove use of G_IO_IN at same time as HUP/ERR since. It is
> >    not required since the websock source doesn't do a real
> >    poll itself.
> >
> >  io/channel-websock.c | 8 +++++++-
> >  1 file changed, 7 insertions(+), 1 deletion(-)
> >
> > diff --git a/io/channel-websock.c b/io/channel-websock.c
> > index dc43dc6bb9..77d30f0e4a 100644
> > --- a/io/channel-websock.c
> > +++ b/io/channel-websock.c
> > @@ -1225,12 +1225,18 @@ qio_channel_websock_source_check(GSource *source)
> >      QIOChannelWebsockSource *wsource = (QIOChannelWebsockSource *)source;
> >      GIOCondition cond = 0;
> >
> > -    if (wsource->wioc->rawinput.offset || wsource->wioc->io_eof) {
> > +    if (wsource->wioc->rawinput.offset) {
> >          cond |= G_IO_IN;
> >      }
> >      if (wsource->wioc->encoutput.offset < QIO_CHANNEL_WEBSOCK_MAX_BUFFER) {
> >          cond |= G_IO_OUT;
> >      }
> > +    if (wsource->wioc->io_eof) {
> > +        cond |= G_IO_HUP;
> > +    }
> > +    if (wsource->wioc->io_err) {
> > +        cond |= G_IO_ERR;
> > +    }
> >
> >      return cond & wsource->condition;
> >  }
> > --
> > 2.20.1
> >

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>