From patchwork Thu Oct 31 15:53:49 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Daniel_P=2E_Berrang=C3=A9?= X-Patchwork-Id: 13858124 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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 5B0D7D767E0 for ; Thu, 31 Oct 2024 15:54:57 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1t6XUy-0005Nl-DE; Thu, 31 Oct 2024 11:54:12 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1t6XUw-0005NH-D6 for qemu-devel@nongnu.org; Thu, 31 Oct 2024 11:54:10 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1t6XUt-0006KX-DF for qemu-devel@nongnu.org; Thu, 31 Oct 2024 11:54:09 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1730390046; 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=XOdL1KTzerHFUwTSFzsMidxfSqzGyYcF44bdrJkUdk0=; b=fDHtuG13Xgs9tLoGtvtOp1zt1V6RVEoE1GnCg+4YToyPOQF+Iwd0XEoQZB9zV6OPbs1VGG EjZwbjaf4ah3CUvD8SLc2mYgMZBxdVGU4Fw4yO8rrRm7UbSAPwJ9Wio49anLBCCBXsqN4x DzaTyj5y7ik5nebU8WabTlkdxrhXNqo= Received: from mx-prod-mc-02.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-383-nOYgTYpYOWmnp1MZOdbKqQ-1; Thu, 31 Oct 2024 11:54:03 -0400 X-MC-Unique: nOYgTYpYOWmnp1MZOdbKqQ-1 Received: from mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.40]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 9F75D1955EA5 for ; Thu, 31 Oct 2024 15:54:02 +0000 (UTC) Received: from toolbox.redhat.com (unknown [10.42.28.18]) by mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id C748D1956054; Thu, 31 Oct 2024 15:54:00 +0000 (UTC) From: =?utf-8?q?Daniel_P=2E_Berrang=C3=A9?= To: qemu-devel@nongnu.org Cc: Paolo Bonzini , Peter Xu , =?utf-8?q?Daniel_P=2E_Berrang=C3=A9?= Subject: [RFC 4/5] qom: introduce object_new_dynamic() Date: Thu, 31 Oct 2024 15:53:49 +0000 Message-ID: <20241031155350.3240361-5-berrange@redhat.com> In-Reply-To: <20241031155350.3240361-1-berrange@redhat.com> References: <20241031155350.3240361-1-berrange@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.0 on 10.30.177.40 Received-SPF: pass client-ip=170.10.129.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -24 X-Spam_score: -2.5 X-Spam_bar: -- X-Spam_report: (-2.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.366, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org object_new() has a failure scenario where it will assert() if given an abstract type. Callers which are creating objects based on user input, or unknown/untrusted type names, must manually check the result of object_class_is_abstract() before calling object_new() to propagate an Error, instead of asserting. Introduce a object_new_dynamic() method which is a counterpart to object_new() that directly returns an Error, instead of asserting. This new method is to be used where the typename is specified dynamically by code separate from the immediate caller. Signed-off-by: Daniel P. Berrangé --- include/qom/object.h | 27 +++++++++++++++++++++++++++ qom/object.c | 6 ++++++ 2 files changed, 33 insertions(+) diff --git a/include/qom/object.h b/include/qom/object.h index 222c60e205..8c2f3551c5 100644 --- a/include/qom/object.h +++ b/include/qom/object.h @@ -624,14 +624,41 @@ Object *object_new_with_class(ObjectClass *klass, Error **errp); * object_new: * @typename: The name of the type of the object to instantiate. * + * This method should be used where @typename is statically specified + * from a const string at build time, where the caller does not expect + * failure to be possible. + * * This function will initialize a new object using heap allocated memory. * The returned object has a reference count of 1, and will be freed when * the last reference is dropped. * + * If an instance of @typename is not permitted to be instantiated, an + * assert will be raised. This can happen if @typename is abstract. + * * Returns: The newly allocated and instantiated object. */ Object *object_new(const char *typename); +/** + * object_new_dynamic: + * @typename: The name of the type of the object to instantiate. + * @errp: pointer to be filled with error details on failure + * + * This method should be used where @typename is dynamically chosen + * at runtime, which has the possibility of unexpected choices leading + * to failures. + * + * This function will initialize a new object using heap allocated memory. + * The returned object has a reference count of 1, and will be freed when + * the last reference is dropped. + * + * If an instance of @typename is not permitted to be instantiated, an + * error will be raised. This can happen if @typename is abstract. + * + * Returns: The newly allocated and instantiated object. + */ +Object *object_new_dynamic(const char *typename, Error **errp); + /** * object_new_with_props: * @typename: The name of the type of the object to instantiate. diff --git a/qom/object.c b/qom/object.c index 1f139aa9c8..1ed62dc2c9 100644 --- a/qom/object.c +++ b/qom/object.c @@ -807,6 +807,12 @@ Object *object_new(const char *typename) return object_new_with_type(ti, &error_abort); } +Object *object_new_dynamic(const char *typename, Error **errp) +{ + TypeImpl *ti = type_get_by_name(typename); + + return object_new_with_type(ti, errp); +} Object *object_new_with_props(const char *typename, Object *parent,