From patchwork Tue Sep 24 20:08:41 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Vladimir Sementsov-Ogievskiy X-Patchwork-Id: 1166834 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=virtuozzo.com 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 ozlabs.org (Postfix) with ESMTPS id 46dC7Y4Xd3z9sNk for ; Wed, 25 Sep 2019 06:13:45 +1000 (AEST) Received: from localhost ([::1]:50610 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iCrBv-0004ox-48 for incoming@patchwork.ozlabs.org; Tue, 24 Sep 2019 16:13:43 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:43743) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iCr8B-0000XG-0L for qemu-devel@nongnu.org; Tue, 24 Sep 2019 16:09:53 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iCr89-0002ru-0V for qemu-devel@nongnu.org; Tue, 24 Sep 2019 16:09:50 -0400 Received: from relay.sw.ru ([185.231.240.75]:38042) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iCr88-0002qu-Nm; Tue, 24 Sep 2019 16:09:48 -0400 Received: from [10.94.3.0] (helo=kvm.qa.sw.ru) by relay.sw.ru with esmtp (Exim 4.92.2) (envelope-from ) id 1iCr86-0001Mk-Qn; Tue, 24 Sep 2019 23:09:46 +0300 From: Vladimir Sementsov-Ogievskiy To: qemu-devel@nongnu.org Subject: [PATCH v3 04/25] error: auto propagated local_err Date: Tue, 24 Sep 2019 23:08:41 +0300 Message-Id: <20190924200902.4703-5-vsementsov@virtuozzo.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190924200902.4703-1-vsementsov@virtuozzo.com> References: <20190924200902.4703-1-vsementsov@virtuozzo.com> MIME-Version: 1.0 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 185.231.240.75 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: Fam Zheng , Paul Burton , Peter Maydell , Jeff Cody , Jason Wang , Mark Cave-Ayland , Michael Roth , Gerd Hoffmann , Subbaraya Sundeep , qemu-block@nongnu.org, Juan Quintela , Aleksandar Rikalo , "Michael S. Tsirkin" , Markus Armbruster , Halil Pasic , Christian Borntraeger , =?utf-8?q?Marc-Andr?= =?utf-8?b?w6kgTHVyZWF1?= , David Gibson , Eric Farman , Eduardo Habkost , Greg Kurz , Yuval Shaia , "Dr. David Alan Gilbert" , Alex Williamson , integration@gluster.org, David Hildenbrand , John Snow , Richard Henderson , Kevin Wolf , vsementsov@virtuozzo.com, =?utf-8?q?Daniel_P=2E_Berrang=C3=A9?= , Cornelia Huck , qemu-s390x@nongnu.org, Max Reitz , qemu-arm@nongnu.org, qemu-ppc@nongnu.org, Paolo Bonzini Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" Here is introduced ERRP_FUNCTION_BEGIN macro, to be used at start of functions with errp parameter. It has three goals: 1. Fix issue with error_fatal & error_append_hint: user can't see these hints, because exit() happens in error_setg earlier than hint is appended. [Reported by Greg Kurz] 2. Fix issue with error_abort & error_propagate: when we wrap error_abort by local_err+error_propagate, resulting coredump will refer to error_propagate and not to the place where error happened. (the macro itself doesn't fix the issue, but it allows to [3.] drop all local_err+error_propagate pattern, which will definitely fix the issue) [Reported by Kevin Wolf] 3. Drop local_err+error_propagate pattern, which is used to workaround void functions with errp parameter, when caller wants to know resulting status. (Note: actually these functions could be merely updated to return int error code). Signed-off-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Eric Blake --- CC: John Snow CC: Kevin Wolf CC: Max Reitz CC: Fam Zheng CC: Jeff Cody CC: "Marc-André Lureau" CC: Paolo Bonzini CC: Greg Kurz CC: Subbaraya Sundeep CC: Peter Maydell CC: Paul Burton CC: Aleksandar Rikalo CC: "Michael S. Tsirkin" CC: Marcel Apfelbaum CC: Mark Cave-Ayland CC: David Gibson CC: Yuval Shaia CC: Cornelia Huck CC: Eric Farman CC: Richard Henderson CC: David Hildenbrand CC: Halil Pasic CC: Christian Borntraeger CC: Gerd Hoffmann CC: Alex Williamson CC: Markus Armbruster CC: Michael Roth CC: Juan Quintela CC: "Dr. David Alan Gilbert" CC: Eric Blake CC: Jason Wang CC: "Daniel P. Berrangé" CC: Eduardo Habkost CC: qemu-block@nongnu.org CC: qemu-devel@nongnu.org CC: integration@gluster.org CC: qemu-arm@nongnu.org CC: qemu-ppc@nongnu.org CC: qemu-s390x@nongnu.org include/qapi/error.h | 35 +++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) diff --git a/include/qapi/error.h b/include/qapi/error.h index 9376f59c35..fb41f7a790 100644 --- a/include/qapi/error.h +++ b/include/qapi/error.h @@ -322,6 +322,41 @@ void error_set_internal(Error **errp, ErrorClass err_class, const char *fmt, ...) GCC_FMT_ATTR(6, 7); +typedef struct ErrorPropagator { + Error *local_err; + Error **errp; +} ErrorPropagator; + +static inline void error_propagator_cleanup(ErrorPropagator *prop) +{ + error_propagate(prop->errp, prop->local_err); +} + +G_DEFINE_AUTO_CLEANUP_CLEAR_FUNC(ErrorPropagator, error_propagator_cleanup); + +/* + * ERRP_FUNCTION_BEGIN + * + * This macro is created to be the first line of a function with Error **errp + * parameter. + * + * If errp is NULL or points to error_fatal, it is rewritten to point to a + * local Error object, which will be automatically propagated to the original + * errp on function exit (see error_propagator_cleanup). + * + * After invocation of this macro it is always safe to dereference errp + * (as it's not NULL anymore) and to append hints (by error_append_hint) + * (as, if it was error_fatal, we swapped it with a local_error to be + * propagated on cleanup). + * + * Note: we don't wrap the error_abort case, as we want resulting coredump + * to point to the place where the error happened, not to error_propagate. + */ +#define ERRP_FUNCTION_BEGIN() \ +g_auto(ErrorPropagator) __auto_errp_prop = {.errp = errp}; \ +errp = ((errp == NULL || *errp == error_fatal) ? \ + &__auto_errp_prop.local_err : errp) + /* * Special error destination to abort on error. * See error_setg() and error_propagate() for details.