From patchwork Thu May 12 07:58:49 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Markus Armbruster X-Patchwork-Id: 9077411 Return-Path: X-Original-To: patchwork-qemu-devel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 62E64BF29F for ; Thu, 12 May 2016 08:06:43 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 8B750201F5 for ; Thu, 12 May 2016 08:06:42 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 7E327201EC for ; Thu, 12 May 2016 08:06:41 +0000 (UTC) Received: from localhost ([::1]:55903 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1b0ldo-0004yE-GR for patchwork-qemu-devel@patchwork.kernel.org; Thu, 12 May 2016 04:06:40 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54129) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1b0lWj-0000tq-4G for qemu-devel@nongnu.org; Thu, 12 May 2016 03:59:29 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1b0lWc-0006J9-F9 for qemu-devel@nongnu.org; Thu, 12 May 2016 03:59:20 -0400 Received: from mx1.redhat.com ([209.132.183.28]:57328) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1b0lWc-0006Iu-3j for qemu-devel@nongnu.org; Thu, 12 May 2016 03:59:14 -0400 Received: from int-mx14.intmail.prod.int.phx2.redhat.com (int-mx14.intmail.prod.int.phx2.redhat.com [10.5.11.27]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 9280B80083 for ; Thu, 12 May 2016 07:59:13 +0000 (UTC) Received: from blackfin.pond.sub.org (ovpn-116-35.ams2.redhat.com [10.36.116.35]) by int-mx14.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u4C7xARc024016 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Thu, 12 May 2016 03:59:12 -0400 Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 6D08F1132D8C; Thu, 12 May 2016 09:59:10 +0200 (CEST) From: Markus Armbruster To: qemu-devel@nongnu.org Date: Thu, 12 May 2016 09:58:49 +0200 Message-Id: <1463039950-4021-3-git-send-email-armbru@redhat.com> In-Reply-To: <1463039950-4021-1-git-send-email-armbru@redhat.com> References: <1463039950-4021-1-git-send-email-armbru@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.27 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Thu, 12 May 2016 07:59:13 +0000 (UTC) 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] [PULL 02/23] qapi: Guarantee NULL obj on input visitor callback error X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Eric Blake Our existing input visitors were not very consistent on errors in a function taking 'TYPE **obj'. These are start_struct(), start_alternate(), type_str(), and type_any(). next_list() is similar, but can't fail (see commit 08f9541). While all of them set '*obj' to allocated storage on success, it was not obvious whether '*obj' was guaranteed safe on failure, or whether it was left uninitialized. But a future patch wants to guarantee that visit_type_FOO() does not leak a partially-constructed obj back to the caller; it is easier to implement this if we can reliably state that input visitors assign '*obj' regardless of success or failure, and that on failure *obj is NULL. Add assertions to enforce consistency in the final setting of err vs. *obj. The opts-visitor start_struct() doesn't set an error, but it also was doing a weird check for 0 size; all callers pass in non-zero size if obj is non-NULL. The testsuite has at least one spot where we no longer need to pre-initialize a variable prior to a visit; valgrind confirms that the test is still fine with the cleanup. A later patch will document the design constraint implemented here. Signed-off-by: Eric Blake Message-Id: <1461879932-9020-3-git-send-email-eblake@redhat.com> [visit_start_alternate()'s assertion tightened, commit message tweaked] Signed-off-by: Markus Armbruster --- qapi/opts-visitor.c | 3 ++- qapi/qapi-visit-core.c | 34 ++++++++++++++++++++++++++++++---- qapi/qmp-input-visitor.c | 4 ++++ qapi/string-input-visitor.c | 1 + tests/test-qmp-input-strict.c | 2 +- 5 files changed, 38 insertions(+), 6 deletions(-) diff --git a/qapi/opts-visitor.c b/qapi/opts-visitor.c index 66aeaed..4cb6436 100644 --- a/qapi/opts-visitor.c +++ b/qapi/opts-visitor.c @@ -133,7 +133,7 @@ opts_start_struct(Visitor *v, const char *name, void **obj, const QemuOpt *opt; if (obj) { - *obj = g_malloc0(size > 0 ? size : 1); + *obj = g_malloc0(size); } if (ov->depth++ > 0) { return; @@ -314,6 +314,7 @@ opts_type_str(Visitor *v, const char *name, char **obj, Error **errp) opt = lookup_scalar(ov, name, errp); if (!opt) { + *obj = NULL; return; } *obj = g_strdup(opt->str ? opt->str : ""); diff --git a/qapi/qapi-visit-core.c b/qapi/qapi-visit-core.c index 3cd7edc..528092e 100644 --- a/qapi/qapi-visit-core.c +++ b/qapi/qapi-visit-core.c @@ -23,7 +23,13 @@ void visit_start_struct(Visitor *v, const char *name, void **obj, size_t size, Error **errp) { - v->start_struct(v, name, obj, size, errp); + Error *err = NULL; + + v->start_struct(v, name, obj, size, &err); + if (obj && v->type == VISITOR_INPUT) { + assert(!err != !*obj); + } + error_propagate(errp, err); } void visit_end_struct(Visitor *v, Error **errp) @@ -51,10 +57,16 @@ void visit_start_alternate(Visitor *v, const char *name, GenericAlternate **obj, size_t size, bool promote_int, Error **errp) { + Error *err = NULL; + assert(obj && size >= sizeof(GenericAlternate)); if (v->start_alternate) { - v->start_alternate(v, name, obj, size, promote_int, errp); + v->start_alternate(v, name, obj, size, promote_int, &err); } + if (v->type == VISITOR_INPUT) { + assert(v->start_alternate && !err != !*obj); + } + error_propagate(errp, err); } void visit_end_alternate(Visitor *v) @@ -188,7 +200,14 @@ void visit_type_bool(Visitor *v, const char *name, bool *obj, Error **errp) void visit_type_str(Visitor *v, const char *name, char **obj, Error **errp) { - v->type_str(v, name, obj, errp); + Error *err = NULL; + + assert(obj); + v->type_str(v, name, obj, &err); + if (v->type == VISITOR_INPUT) { + assert(!err != !*obj); + } + error_propagate(errp, err); } void visit_type_number(Visitor *v, const char *name, double *obj, @@ -199,7 +218,14 @@ void visit_type_number(Visitor *v, const char *name, double *obj, void visit_type_any(Visitor *v, const char *name, QObject **obj, Error **errp) { - v->type_any(v, name, obj, errp); + Error *err = NULL; + + assert(obj); + v->type_any(v, name, obj, &err); + if (v->type == VISITOR_INPUT) { + assert(!err != !*obj); + } + error_propagate(errp, err); } static void output_type_enum(Visitor *v, const char *name, int *obj, diff --git a/qapi/qmp-input-visitor.c b/qapi/qmp-input-visitor.c index 02d4233..77cce8b 100644 --- a/qapi/qmp-input-visitor.c +++ b/qapi/qmp-input-visitor.c @@ -120,6 +120,9 @@ static void qmp_input_start_struct(Visitor *v, const char *name, void **obj, QObject *qobj = qmp_input_get_object(qiv, name, true); Error *err = NULL; + if (obj) { + *obj = NULL; + } if (!qobj || qobject_type(qobj) != QTYPE_QDICT) { error_setg(errp, QERR_INVALID_PARAMETER_TYPE, name ? name : "null", "QDict"); @@ -267,6 +270,7 @@ static void qmp_input_type_str(Visitor *v, const char *name, char **obj, QString *qstr = qobject_to_qstring(qmp_input_get_object(qiv, name, true)); if (!qstr) { + *obj = NULL; error_setg(errp, QERR_INVALID_PARAMETER_TYPE, name ? name : "null", "string"); return; diff --git a/qapi/string-input-visitor.c b/qapi/string-input-visitor.c index 97009a6..b55d199 100644 --- a/qapi/string-input-visitor.c +++ b/qapi/string-input-visitor.c @@ -293,6 +293,7 @@ static void parse_type_str(Visitor *v, const char *name, char **obj, if (siv->string) { *obj = g_strdup(siv->string); } else { + *obj = NULL; error_setg(errp, QERR_INVALID_PARAMETER_TYPE, name ? name : "null", "string"); } diff --git a/tests/test-qmp-input-strict.c b/tests/test-qmp-input-strict.c index d71727e..d5f80ec 100644 --- a/tests/test-qmp-input-strict.c +++ b/tests/test-qmp-input-strict.c @@ -263,7 +263,7 @@ static void test_validate_fail_union_flat_no_discrim(TestInputVisitorData *data, static void test_validate_fail_alternate(TestInputVisitorData *data, const void *unused) { - UserDefAlternate *tmp = NULL; + UserDefAlternate *tmp; Visitor *v; Error *err = NULL;