From patchwork Tue Oct 1 15:52:52 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vladimir Sementsov-Ogievskiy X-Patchwork-Id: 1170059 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 46jPhf07SKz9sDB for ; Wed, 2 Oct 2019 02:23:30 +1000 (AEST) Received: from localhost ([::1]:44356 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iFKvv-0003yV-7P for incoming@patchwork.ozlabs.org; Tue, 01 Oct 2019 12:23:27 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:50410) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iFKU0-0000jN-C5 for qemu-devel@nongnu.org; Tue, 01 Oct 2019 11:54:37 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iFKTy-0007Ec-5G for qemu-devel@nongnu.org; Tue, 01 Oct 2019 11:54:36 -0400 Received: from relay.sw.ru ([185.231.240.75]:38470) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iFKTr-0006Zo-8W; Tue, 01 Oct 2019 11:54:33 -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 1iFKSw-0004xb-Of; Tue, 01 Oct 2019 18:53:30 +0300 From: Vladimir Sementsov-Ogievskiy To: qemu-devel@nongnu.org Subject: [PATCH v4 04/31] error: auto propagated local_err Date: Tue, 1 Oct 2019 18:52:52 +0300 Message-Id: <20191001155319.8066-5-vsementsov@virtuozzo.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20191001155319.8066-1-vsementsov@virtuozzo.com> References: <20191001155319.8066-1-vsementsov@virtuozzo.com> MIME-Version: 1.0 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [fuzzy] 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@euphon.net, pburton@wavecomp.com, peter.maydell@linaro.org, codyprime@gmail.com, jasowang@redhat.com, mark.cave-ayland@ilande.co.uk, mdroth@linux.vnet.ibm.com, kraxel@redhat.com, sundeep.lkml@gmail.com, qemu-block@nongnu.org, quintela@redhat.com, arikalo@wavecomp.com, mst@redhat.com, armbru@redhat.com, pasic@linux.ibm.com, borntraeger@de.ibm.com, joel@jms.id.au, marcandre.lureau@redhat.com, rth@twiddle.net, farman@linux.ibm.com, ehabkost@redhat.com, sw@weilnetz.de, groug@kaod.org, yuval.shaia@oracle.com, dgilbert@redhat.com, alex.williamson@redhat.com, integration@gluster.org, clg@kaod.org, stefanha@redhat.com, david@redhat.com, jsnow@redhat.com, david@gibson.dropbear.id.au, kwolf@redhat.com, Vladimir Sementsov-Ogievskiy , berrange@redhat.com, andrew@aj.id.au, cohuck@redhat.com, qemu-s390x@nongnu.org, mreitz@redhat.com, qemu-arm@nongnu.org, qemu-ppc@nongnu.org, pbonzini@redhat.com Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" Here is introduced ERRP_AUTO_PROPAGATE macro, to be used at start of functions with errp OUT parameter. It has three goals: 1. Fix issue with error_fatal & error_prepend/error_append_hint: user can't see this additional information, because exit() happens in error_setg earlier than information is added. [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: kwolf@redhat.com CC: mreitz@redhat.com CC: jsnow@redhat.com CC: fam@euphon.net CC: sw@weilnetz.de CC: codyprime@gmail.com CC: marcandre.lureau@redhat.com CC: pbonzini@redhat.com CC: groug@kaod.org CC: sundeep.lkml@gmail.com CC: peter.maydell@linaro.org CC: stefanha@redhat.com CC: pburton@wavecomp.com CC: arikalo@wavecomp.com CC: berrange@redhat.com CC: ehabkost@redhat.com CC: david@gibson.dropbear.id.au CC: clg@kaod.org CC: mst@redhat.com CC: marcel.apfelbaum@gmail.com CC: mark.cave-ayland@ilande.co.uk CC: yuval.shaia@oracle.com CC: cohuck@redhat.com CC: farman@linux.ibm.com CC: rth@twiddle.net CC: david@redhat.com CC: pasic@linux.ibm.com CC: borntraeger@de.ibm.com CC: kraxel@redhat.com CC: alex.williamson@redhat.com CC: andrew@aj.id.au CC: joel@jms.id.au CC: eblake@redhat.com CC: armbru@redhat.com CC: mdroth@linux.vnet.ibm.com CC: quintela@redhat.com CC: dgilbert@redhat.com CC: jasowang@redhat.com CC: qemu-block@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 | 37 +++++++++++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+) diff --git a/include/qapi/error.h b/include/qapi/error.h index 9376f59c35..02f967ac1d 100644 --- a/include/qapi/error.h +++ b/include/qapi/error.h @@ -322,6 +322,43 @@ 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_AUTO_PROPAGATE + * + * This macro is created to be the first line of a function with Error **errp + * OUT parameter. It's needed only in cases where we want to use error_prepend, + * error_append_hint or dereference *errp. It's still safe (but useless) in + * other cases. + * + * 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_AUTO_PROPAGATE() \ +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.