From nobody Wed Oct 1 02:37:20 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 15451626887821000.2066468242336; Tue, 18 Dec 2018 11:51:28 -0800 (PST) Received: from localhost ([::1]:55617 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gZJbB-0007ry-Iu for importer@patchew.org; Tue, 18 Dec 2018 12:56:05 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:33372) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gZJXc-0004w7-Jr for qemu-devel@nongnu.org; Tue, 18 Dec 2018 12:52:28 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gZJXb-0002jG-B4 for qemu-devel@nongnu.org; Tue, 18 Dec 2018 12:52:24 -0500 Received: from mx1.redhat.com ([209.132.183.28]:39544) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1gZJXP-0002MZ-Ks; Tue, 18 Dec 2018 12:52:13 -0500 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id BA84EC04AC54; Tue, 18 Dec 2018 17:52:09 +0000 (UTC) Received: from x1w.redhat.com (ovpn-204-92.brq.redhat.com [10.40.204.92]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 47398105B1E2; Tue, 18 Dec 2018 17:51:48 +0000 (UTC) From: =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= To: qemu-devel@nongnu.org Date: Tue, 18 Dec 2018 18:51:18 +0100 Message-Id: <20181218175122.3229-2-philmd@redhat.com> In-Reply-To: <20181218175122.3229-1-philmd@redhat.com> References: <20181218175122.3229-1-philmd@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.31]); Tue, 18 Dec 2018 17:52:09 +0000 (UTC) Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH v3 1/5] qemu/compiler: Define QEMU_NONSTRING 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: , Cc: "Michael S. Tsirkin" , Jeff Cody , Ben Pye , qemu-block@nongnu.org, Juan Quintela , David Hildenbrand , Markus Armbruster , =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= , Liu Yuan , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= , Thomas Huth , Stefan Weil , Howard Spoelstra , "Dr. David Alan Gilbert" , =?UTF-8?q?C=C3=A9dric=20Le=20Goater?= , Paolo Bonzini , David Gibson , Kevin Wolf , Max Reitz , 1803872@bugs.launchpad.net, Igor Mammedov Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" Content-Type: text/plain; charset="utf-8" GCC 8 introduced the -Wstringop-truncation checker to detect truncation by the strncat and strncpy functions (closely related to -Wstringop-overflow, which detect buffer overflow by string-modifying functions declared in ). Add the QEMU_NONSTRING macro which checks if the compiler supports this attribute. From the GCC manual [*]: The nonstring variable attribute specifies that an object or member declaration with type array of char, signed char, or unsigned char, or pointer to such a type is intended to store character arrays that do not necessarily contain a terminating NUL. This is useful in detecting uses of such arrays or pointers with functions that expect NUL-terminated strings, and to avoid warnings when such an array or pointer is used as an argument to a bounded string manipulation function such as strncpy. [*] https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#inde= x-nonstring-variable-attribute Suggested-by: Michael S. Tsirkin Signed-off-by: Philippe Mathieu-Daud=C3=A9 --- include/qemu/compiler.h | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/include/qemu/compiler.h b/include/qemu/compiler.h index 261842beae..2d8f507c73 100644 --- a/include/qemu/compiler.h +++ b/include/qemu/compiler.h @@ -151,6 +151,21 @@ # define QEMU_ERROR(X) #endif =20 +/* + * The nonstring variable attribute specifies that an object or member + * declaration with type array of char or pointer to char is intended + * to store character arrays that do not necessarily contain a terminating + * NUL character. This is useful in detecting uses of such arrays or point= ers + * with functions that expect NUL-terminated strings, and to avoid warnings + * when such an array or pointer is used as an argument to a bounded string + * manipulation function such as strncpy. + */ +#if __has_attribute(nonstring) +# define QEMU_NONSTRING __attribute__((nonstring)) +#else +# define QEMU_NONSTRING +#endif + /* Implement C11 _Generic via GCC builtins. Example: * * QEMU_GENERIC(x, (float, sinf), (long double, sinl), sin) (x) --=20 2.17.2