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 X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 613CBC43331 for ; Thu, 5 Sep 2019 15:23:23 +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 BF08620820 for ; Thu, 5 Sep 2019 15:23:23 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BF08620820 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:47196 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1i5tbV-0001Ot-Pd for qemu-devel@archiver.kernel.org; Thu, 05 Sep 2019 11:23:21 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:42703) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1i5ta1-0008T4-NL for qemu-devel@nongnu.org; Thu, 05 Sep 2019 11:21:51 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1i5ta0-0007au-5K for qemu-devel@nongnu.org; Thu, 05 Sep 2019 11:21:49 -0400 Received: from mx1.redhat.com ([209.132.183.28]:50494) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1i5tZz-0007a6-Uw for qemu-devel@nongnu.org; Thu, 05 Sep 2019 11:21:48 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id C2039307D915; Thu, 5 Sep 2019 15:21:46 +0000 (UTC) Received: from localhost (ovpn-117-222.ams2.redhat.com [10.36.117.222]) by smtp.corp.redhat.com (Postfix) with ESMTP id B50C619C69; Thu, 5 Sep 2019 15:21:37 +0000 (UTC) From: Stefan Hajnoczi To: qemu-devel@nongnu.org, virtio-fs@redhat.com Date: Thu, 5 Sep 2019 16:21:33 +0100 Message-Id: <20190905152136.30637-1-stefanha@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.48]); Thu, 05 Sep 2019 15:21:46 +0000 (UTC) Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [RFC 0/3] virtiofsd: get/set log level via DBus 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: =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= , Eryu Guan , "Dr. David Alan Gilbert" , Stefan Hajnoczi Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" It is likely that virtiofsd will need to support "management commands" fo= r reconfiguring it at runtime. The first use case was proposed by Eryu Gua= n for getting/setting the current log level. I promised to try out DBus as the management interface because it has a r= ich feature set and is accessible from most programming languages. It should= be able to support all the use cases we come up with. This patch series is a prototype that implements the get-log-level and set-log-level management commands via DBus. Use the new virtiofsctl tool= to talk to a running virtiofsd process: # dbus-run-session ./virtiofsd ... ... Using dbus address unix:abstract=3D/tmp/dbus-H9WBbpjk3O,guid=3D0be16ace= fb868e6025a8737f5d7124d2 # export DBUS_SESSION_BUS_ADDRESS=3Dunix:abstract=3D/tmp/dbus-H9WBbpjk3= O,guid=3D0be16acefb868e6025a8737f5d7124d2 # ./virtiofsctl set-log-level err Most of the work is done by gdbus-codegen(1). It generates code for the org.qemu.Virtiofsd.xml interface definition. Our code can use the simple virtiofsd_get/set_log_level() APIs and it will make corresponding DBus ca= lls. I'm pretty happy with this approach because the code is straightforward. = It hasn't even triggered seccomp failures yet :). Error handling is a little problematic. I noticed that virtiofsctl silen= tly returns success even if it cannot talk to virtiofsd. This is due to the = code generated by gdbus-codegen(1) which has no error reporting :(. This can = be solved by writing more low-level GDBus code instead of using the high-lev= el generated bindings. What do you think about this approach? Stefan Hajnoczi (3): virtiofsd: add org.qemu.Virtiofsd interface virtiofsd: add DBus server to handle log level changes virtiofsd: add virtiofsctl command-line management tool configure | 7 + Makefile | 16 +++ Makefile.objs | 1 + contrib/virtiofsd/Makefile.objs | 10 +- contrib/virtiofsd/dbus.h | 9 ++ contrib/virtiofsd/dbus.c | 162 +++++++++++++++++++++++ contrib/virtiofsd/passthrough_ll.c | 8 +- contrib/virtiofsd/virtiofsctl.c | 55 ++++++++ .gitignore | 1 + contrib/virtiofsd/org.qemu.Virtiofsd.xml | 7 + 10 files changed, 274 insertions(+), 2 deletions(-) create mode 100644 contrib/virtiofsd/dbus.h create mode 100644 contrib/virtiofsd/dbus.c create mode 100644 contrib/virtiofsd/virtiofsctl.c create mode 100644 contrib/virtiofsd/org.qemu.Virtiofsd.xml --=20 2.21.0