From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 475DFC433FE for ; Tue, 12 Oct 2021 21:46:15 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id DC2B96109E for ; Tue, 12 Oct 2021 21:46:14 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org DC2B96109E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=nongnu.org Received: from localhost ([::1]:54856 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1maPbB-0000Ct-UE for qemu-devel@archiver.kernel.org; Tue, 12 Oct 2021 17:46:13 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:53954) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1maPYF-0005HE-Ma for qemu-devel@nongnu.org; Tue, 12 Oct 2021 17:43:11 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:48845) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1maPYD-0000Al-2C for qemu-devel@nongnu.org; Tue, 12 Oct 2021 17:43:10 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1634074988; 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=X3cObBRMQphyn29U3tGO/4DWuh7E5gTFgokPzSEt9Ig=; b=FtOtHcMEzMCtkvd8UqNLxuA4BoMlXS57J+UlYxIS71btFVqc/UeGcRS8/RPvRVwigc/3Rm OQJdV2LA4JFjs1/3PvxsXfOvIXydMkVWDXuRrksVfKuORDchcoNR2rwpnAlXXIj27O7Kaz fckeNaMsjnT5tPAkF9JEyxzLQ0pB/PI= 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-356-5M0ka2H3M9ysUpgPLui2Tw-1; Tue, 12 Oct 2021 17:43:05 -0400 X-MC-Unique: 5M0ka2H3M9ysUpgPLui2Tw-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 48FE81006AA2; Tue, 12 Oct 2021 21:43:04 +0000 (UTC) Received: from scv.redhat.com (unknown [10.22.16.191]) by smtp.corp.redhat.com (Postfix) with ESMTP id 990695D6A8; Tue, 12 Oct 2021 21:43:02 +0000 (UTC) From: John Snow To: qemu-devel@nongnu.org Subject: [PULL 04/10] python/aqmp: add send_fd_scm Date: Tue, 12 Oct 2021 17:41:46 -0400 Message-Id: <20211012214152.802483-5-jsnow@redhat.com> In-Reply-To: <20211012214152.802483-1-jsnow@redhat.com> References: <20211012214152.802483-1-jsnow@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 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: 8bit Content-Type: text/plain; charset="US-ASCII" Received-SPF: pass client-ip=170.10.133.124; envelope-from=jsnow@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -8 X-Spam_score: -0.9 X-Spam_bar: / X-Spam_report: (-0.9 / 5.0 requ) DKIMWL_WL_HIGH=-0.049, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable 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 , Peter Maydell , Thomas Huth , Daniel Berrange , Eduardo Habkost , qemu-block@nongnu.org, =?UTF-8?q?Alex=20Benn=C3=A9e?= , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= , Wainer dos Santos Moschetta , Markus Armbruster , Willian Rampazzo , Hanna Reitz , Cleber Rosa , Paolo Bonzini , John Snow , Eric Blake Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Add an implementation for send_fd_scm to the async QMP implementation. Like socket_scm_helper mentions, a non-empty payload is required for QEMU to process the ancillary data. A space is most useful because it does not disturb the parsing of subsequent JSON objects. A note on "voiding the warranty": 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: Paolo Bonzini Reviewed-by: Eric Blake Message-id: 20210923004938.3999963-5-jsnow@redhat.com Signed-off-by: John Snow --- 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 @@ import asyncio import logging +import socket +import struct from typing import ( Dict, List, @@ -624,3 +626,23 @@ 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') + + if sock.family != socket.AF_UNIX: + raise AQMPError("Sending file descriptors requires a UNIX socket.") + + # Void the warranty sticker. + # Access to sendmsg in asyncio is scheduled for removal in Python 3.11. + sock = sock._sock # pylint: disable=protected-access + sock.sendmsg( + [b' '], + [(socket.SOL_SOCKET, socket.SCM_RIGHTS, struct.pack('@i', fd))] + ) -- 2.31.1