[libvirt] [PATCH 01/11] Process all pending I/O for a RPC client before checking EOF

[Jiri Denemark]

On Tue, Jul 24, 2012 at 14:22:43 +0100, Daniel P. Berrange wrote:
> From: "Daniel P. Berrange" <berrange at redhat.com>
> 
> In the socket event handler for the RPC client we must deal
> with read/write events, before checking for EOF, otherwise
> we might close the socket before we've read & acted upon the
> last RPC messages
> 
> Signed-off-by: Daniel P. Berrange <berrange at redhat.com>
> ---
>  src/rpc/virnetclient.c |   20 ++++++++++----------
>  1 file changed, 10 insertions(+), 10 deletions(-)
> 
> diff --git a/src/rpc/virnetclient.c b/src/rpc/virnetclient.c
> index aba58ec..f5d8189 100644
> --- a/src/rpc/virnetclient.c
> +++ b/src/rpc/virnetclient.c
> @@ -1694,16 +1694,6 @@ void virNetClientIncomingEvent(virNetSocketPtr sock,
>  
>      VIR_DEBUG("Event fired %p %d", sock, events);
>  
> -    if (events & (VIR_EVENT_HANDLE_HANGUP | VIR_EVENT_HANDLE_ERROR)) {
> -        VIR_DEBUG("%s : VIR_EVENT_HANDLE_HANGUP or "
> -                  "VIR_EVENT_HANDLE_ERROR encountered", __FUNCTION__);
> -        virNetClientMarkClose(client,
> -                              (events & VIR_EVENT_HANDLE_HANGUP) ?
> -                              VIR_CONNECT_CLOSE_REASON_EOF :
> -                              VIR_CONNECT_CLOSE_REASON_ERROR);
> -        goto done;
> -    }
> -
>      if (events & VIR_EVENT_HANDLE_WRITABLE) {
>          if (virNetClientIOHandleOutput(client) < 0)
>              virNetClientMarkClose(client, VIR_CONNECT_CLOSE_REASON_ERROR);
> @@ -1714,6 +1704,16 @@ void virNetClientIncomingEvent(virNetSocketPtr sock,
>              virNetClientMarkClose(client, VIR_CONNECT_CLOSE_REASON_ERROR);
>      }
>  
> +    if (events & (VIR_EVENT_HANDLE_HANGUP | VIR_EVENT_HANDLE_ERROR)) {
> +        VIR_DEBUG("%s : VIR_EVENT_HANDLE_HANGUP or "
> +                  "VIR_EVENT_HANDLE_ERROR encountered", __FUNCTION__);

I know you are just copy&pasting but __FUNCTION__ is redundant here.

> +        virNetClientMarkClose(client,
> +                              (events & VIR_EVENT_HANDLE_HANGUP) ?
> +                              VIR_CONNECT_CLOSE_REASON_EOF :
> +                              VIR_CONNECT_CLOSE_REASON_ERROR);
> +        goto done;
> +    }
> +
>      /* Remove completed calls or signal their threads. */
>      virNetClientCallRemovePredicate(&client->waitDispatch,
>                                      virNetClientIOEventLoopRemoveDone,

This is a good change but I think it's incomplete. If something fails (e.g.
the connection is closed) while we are inside virNetClientIOHandleOutput(), we
will still skip reading any data possibly waiting for us.

Jirka