From nobody Mon Feb 9 09:16:19 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=fail; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1632358504295505.7298081630572; Wed, 22 Sep 2021 17:55:04 -0700 (PDT) Received: from localhost ([::1]:54766 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mTD0u-0001zU-OS for importer@patchew.org; Wed, 22 Sep 2021 20:55:00 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:55518) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mTCvy-00016p-W7 for qemu-devel@nongnu.org; Wed, 22 Sep 2021 20:49:55 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:21363) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mTCvx-0006Kz-7J for qemu-devel@nongnu.org; Wed, 22 Sep 2021 20:49:54 -0400 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-51-H6gQutErP3-ovo0-3aGMPQ-1; Wed, 22 Sep 2021 20:49:50 -0400 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id E83829126B; Thu, 23 Sep 2021 00:49:48 +0000 (UTC) Received: from scv.redhat.com (unknown [10.22.9.55]) by smtp.corp.redhat.com (Postfix) with ESMTP id 56AD260BF1; Thu, 23 Sep 2021 00:49:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1632358192; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=TazgFdhlYSvXSGIvNOm5tmBWwunpcLXO5GGIkemddgQ=; b=Hhf3PpUFpotMeiivjbSxb32ODHLAKP4zimNCRTkiupiXcWOwZ34YyV78s6Q9opCpmliOeQ 0LxPIeG0knlbjIrGaYC9ftIxXQ+Kb9vedYVP1QLY/wRYD6Y2khISWGcGVLsLlyQ2s02CR6 2A0mtlxdpk8IBeh+HWuP2OVHDlqG0Vo= X-MC-Unique: H6gQutErP3-ovo0-3aGMPQ-1 From: John Snow To: qemu-devel@nongnu.org Subject: [PATCH v2 04/17] python/aqmp: add send_fd_scm Date: Wed, 22 Sep 2021 20:49:25 -0400 Message-Id: <20210923004938.3999963-5-jsnow@redhat.com> In-Reply-To: <20210923004938.3999963-1-jsnow@redhat.com> References: <20210923004938.3999963-1-jsnow@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=jsnow@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=170.10.129.124; envelope-from=jsnow@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -42 X-Spam_score: -4.3 X-Spam_bar: ---- X-Spam_report: (-4.3 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1.472, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , Vladimir Sementsov-Ogievskiy , Eduardo Habkost , qemu-block@nongnu.org, Hanna Reitz , Cleber Rosa , John Snow Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) X-ZM-MESSAGEID: 1632358506236100001 Content-Type: text/plain; charset="utf-8" The single space is indeed required to successfully transmit the file descriptor to QEMU. Python 3.11 removes support for calling sendmsg directly from a transport's socket. There is no other interface for doing this, our use case is, I suspect, "quite unique". As far as I can tell, this is safe to do -- send_fd_scm is a synchronous function and we can be guaranteed that the async coroutines will *not* be running when it is invoked. In testing, it works correctly. I investigated quite thoroughly the possibility of creating my own asyncio Transport (The class that ultimately manages the raw socket object) so that I could manage the socket myself, but this is so wildly invasive and unportable I scrapped the idea. It would involve a lot of copy-pasting of various python utilities and classes just to re-create the same infrastructure, and for extremely little benefit. Nah. Just boldly void the warranty instead, while I try to follow up on https://bugs.python.org/issue43232 Signed-off-by: John Snow Reviewed-by: Eric Blake --- python/qemu/aqmp/qmp_client.py | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/python/qemu/aqmp/qmp_client.py b/python/qemu/aqmp/qmp_client.py index d2ad7459f9f..f987da02eb0 100644 --- a/python/qemu/aqmp/qmp_client.py +++ b/python/qemu/aqmp/qmp_client.py @@ -9,6 +9,8 @@ =20 import asyncio import logging +import socket +import struct from typing import ( Dict, List, @@ -624,3 +626,23 @@ async def execute(self, cmd: str, """ msg =3D self.make_execute_msg(cmd, arguments, oob=3Doob) 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 =3D self._writer.transport.get_extra_info('socket') + + if sock.family !=3D socket.AF_UNIX: + raise AQMPError("Sending file descriptors requires a UNIX sock= et.") + + # Void the warranty sticker. + # Access to sendmsg in asyncio is scheduled for removal in Python = 3.11. + sock =3D sock._sock # pylint: disable=3Dprotected-access + sock.sendmsg( + [b' '], + [(socket.SOL_SOCKET, socket.SCM_RIGHTS, struct.pack('@i', fd))] + ) --=20 2.31.1