[Libguestfs] [nbdkit PATCH] nbd: Add vsock-cid= transport option

[Eric Blake]

On 7/7/20 11:26 AM, Richard W.M. Jones wrote:
> On Tue, Jul 07, 2020 at 08:17:31AM -0500, Eric Blake wrote:
>> With new enough libnbd, we already support vsock by virtue of uri=;
>> however, it's also nice to allow direct exposure of the
>> nbd_connect_vsock() api.
>>

>> @@ -320,7 +349,8 @@ nbdplug_after_fork (void)
>>     "[uri=]<URI>            URI of an NBD socket to connect to (if supported).\n" \
>>     "socket=<SOCKNAME>      The Unix socket to connect to.\n" \
>>     "hostname=<HOST>        The hostname for the TCP socket to connect to.\n" \
>> -  "port=<PORT>            TCP port or service name to use (default 10809).\n" \
>> +  "port=<PORT>            TCP/VHOST port or service name to use (default 10809).\n" \
>> +  "vhost_cid=<CID>        The cid for the VSOCK socket to connect to.\n" \

>> +  else if (raw_cid)
>> +#if !USE_VSOCK
>> +    abort ();
>> +#else
>> +    r = nbd_connect_vsock (h->nbd, cid, vport);
>> +#endif
>>     else if (command.size > 0)
>>       r = nbd_connect_systemd_socket_activation (h->nbd, (char **) command.ptr);
>>     else if (socket_fd >= 0)
> 
> I wonder if we should just call the flag "vsock=..."?

Sure, that makes sense.  Doing that for nbdkit as client over vsock 
matches 'nbdkit --vsock' in the other direction for offering server over 
vsock.

> 
> However patch looks good, ACK.
> 
> It may be possible to add a test.  See this example, especially the
> line requires_linux_kernel_version.
> 
> https://github.com/libguestfs/nbdkit/blob/master/tests/test-vsock.sh

Thanks; the test will be a separate commit, but I'll play with the idea.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org