On 17.09.21 07:40, John Snow wrote:
> The single space is indeed required to successfully transmit the file
> descriptor to QEMU.
Yeah, socket_scm_helper.c said “Send a blank to notify qemu”.
> Signed-off-by: John Snow <jsnow@redhat.com>
> ---
> python/qemu/aqmp/qmp_client.py | 17 +++++++++++++++++
> 1 file changed, 17 insertions(+)
>
> diff --git a/python/qemu/aqmp/qmp_client.py b/python/qemu/aqmp/qmp_client.py
> index d2ad7459f9..58f85990bc 100644
> --- a/python/qemu/aqmp/qmp_client.py
> +++ b/python/qemu/aqmp/qmp_client.py
> @@ -9,6 +9,8 @@
>
> import asyncio
> import logging
> +import socket
> +import struct
> from typing import (
> Dict,
> List,
> @@ -624,3 +626,18 @@ async def execute(self, cmd: str,
> """
> msg = self.make_execute_msg(cmd, arguments, oob=oob)
> return await self.execute_msg(msg)
> +
> + @upper_half
> + @require(Runstate.RUNNING)
> + def send_fd_scm(self, fd: int) -> None:
> + """
> + Send a file descriptor to the remote via SCM_RIGHTS.
> + """
> + assert self._writer is not None
> + sock = self._writer.transport.get_extra_info('socket')
> +
> + # Python 3.9+ adds socket.send_fds(...)
> + sock.sendmsg(
> + [b' '],
> + [(socket.SOL_SOCKET, socket.SCM_RIGHTS, struct.pack('@i', fd))]
> + )
AFAIU the socket can be either TCP or a UNIX socket
(AsyncProtocol._do_accept’s docstring sounds this way), so should we
check that this is a UNIX socket? (Or is it fine to just run into the
error that I suspect we would get with a TCP socket?)
Hanna
Uhh, hm. I was going to say "Yeah, just let it fail!" but ... upon going to document what error to expect in this case, I am realizing it fails silently. So, uh, that's not ideal.
I'll fix this to make it bark.
--js