Re: [Qemu-devel] Question on unixsocket-based chardevs and vhost-user

[Paolo Bonzini]

On 28/09/2016 18:56, Felipe Franciosi wrote:
> Hi Daniel/Paolo,
> 
>  
> 
> I have a question regarding this commit:
> 
> -------------8<-------------
> Author:     Daniel P. Berrange <address@hidden>
> AuthorDate: Tue Jan 19 11:14:29 2016 +0000
> Commit:     Paolo Bonzini <address@hidden>
> CommitDate: Tue Jan 26 15:58:11 2016 +0100
> -------------8<-------------
> 
> One of the hunks replace unix_send_msgfds() with io_channel_send_full():
> 
> According to the code (qemu-char.c:968), io_channel_send_full() is just
> ignoring the s->write_msgfds parameter.

Hmm, no, it's passing it down:

        ret = qio_channel_writev_full(
            ioc, &iov, 1,
            fds, nfds, NULL);

See the implementation of qio_channel_socket_writev in io/channel-socket.c.

Thanks,

Paolo

> So my question is: when using a chardev implemented by unix sockets, how
> does one pass file descriptors for vhost-user applications?
> 
> I’m actually searching qemu-char.c for “write_msgfds” and scratching my
> head. There are functions to set it, clear it, etc, but none to send it.