Re: [RFC v4 3/5] io/channel-socket: tolerate AF_PACKET getpeername

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

On Tue, Apr 07, 2026 at 01:05:50PM +0800, Cindy Lu wrote:
> When -chardev socket,fd=... is handed an AF_PACKET socket,
> getpeername() can fail with EOPNOTSUPP instead of ENOTCONN because
> packet sockets are not connection-oriented. qio_channel_socket_set_fd()
> currently treats that as fatal and refuses to wrap the fd, even though
> getsockname() and the local address are still valid.
> 
> Treat EOPNOTSUPP the same way as ENOTCONN and leave remoteAddr empty.
> That keeps existing stream-socket behavior unchanged while allowing
> AF_PACKET fds to be adopted by QIOChannelSocket.
> 
> Signed-off-by: Cindy Lu <lulu@redhat.com>
> ---
>  io/channel-socket.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/io/channel-socket.c b/io/channel-socket.c
> index 3053b35ad8..2ed26aefa3 100644
> --- a/io/channel-socket.c
> +++ b/io/channel-socket.c
> @@ -115,7 +115,11 @@ qio_channel_socket_set_fd(QIOChannelSocket *sioc,
>  
>      if (getpeername(fd, (struct sockaddr *)&sioc->remoteAddr,
>                      &sioc->remoteAddrLen) < 0) {
> -        if (errno == ENOTCONN) {
> +        if (errno == ENOTCONN
> +#ifdef EOPNOTSUPP
> +            || errno == EOPNOTSUPP
> +#endif

Why conditionalize it ?  We use this unconditionally throughout
QEMU code AFAICS, even on Windows.

> +            ) {
>              memset(&sioc->remoteAddr, 0, sizeof(sioc->remoteAddr));
>              sioc->remoteAddrLen = sizeof(sioc->remoteAddr);
>          } else {
> -- 
> 2.52.0
> 
> 

With regards,
Daniel
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