Re: [PATCH 5/6] io/channel-websock: do not lose QIO_CHANNEL_ERR_BLOCK while reading

["Daniel P. Berrangé" <berrange@redhat.com>]

On Mon, Aug 31, 2026 at 12:01:50PM +0200, Denis V. Lunev wrote:
> From: Denis V. Lunev <den@openvz.org>
> 
> qio_channel_websock_handshake_read() folds every negative return from
> qio_channel_read() into -1. QIO_CHANNEL_ERR_BLOCK leaves errp unset, so
> qio_channel_websock_handshake_io() then hands a NULL Error to
> error_get_pretty() and QEMU dies.
> 
> The master channel is non-blocking and, for a wss:// client, is a TLS
> channel. A G_IO_IN wakeup carrying only part of a TLS record makes
> gnutls report EAGAIN, which is all it takes to reach this before the
> client has authenticated.
> 
> ERR_BLOCK here means the headers are not complete yet, which is what a
> 0 return already tells the caller. Report it that way and keep waiting.
> The watch is level triggered, so an incomplete record sitting in the
> socket spins the main loop until the rest of it arrives. That is
> bounded by the round trip and is what every reader layered over TLS
> already does.
> 
> Fixes: 2d1d0e70cf3e ("io: add QIOChannelWebsock class")
> Cc: qemu-stable@nongnu.org
> Cc: Daniel P. Berrangé <berrange@redhat.com>
> Cc: Marc-André Lureau <marcandre.lureau@redhat.com>
> Signed-off-by: Denis V. Lunev <den@openvz.org>
> ---
>  io/channel-websock.c | 3 +++
>  1 file changed, 3 insertions(+)

Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>


With regards,
Daniel
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