From nobody Sun Feb 8 13:46:05 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; 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 209.51.188.17 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 [209.51.188.17]) by mx.zohomail.com with SMTPS id 1547584659599326.7877446479414; Tue, 15 Jan 2019 12:37:39 -0800 (PST) Received: from localhost ([127.0.0.1]:48374 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gjVSs-0000S1-3n for importer@patchew.org; Tue, 15 Jan 2019 15:37:38 -0500 Received: from eggs.gnu.org ([209.51.188.92]:35818) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gjUyv-0008ED-MA for qemu-devel@nongnu.org; Tue, 15 Jan 2019 15:06:44 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gjUyt-0003pN-0c for qemu-devel@nongnu.org; Tue, 15 Jan 2019 15:06:41 -0500 Received: from mx1.redhat.com ([209.132.183.28]:9352) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1gjUys-0003XU-Dd for qemu-devel@nongnu.org; Tue, 15 Jan 2019 15:06:38 -0500 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id E732F2D7EE; Tue, 15 Jan 2019 20:06:14 +0000 (UTC) Received: from redhat.com (ovpn-125-113.rdu2.redhat.com [10.10.125.113]) by smtp.corp.redhat.com (Postfix) with ESMTP id F02FC19751; Tue, 15 Jan 2019 20:06:13 +0000 (UTC) Date: Tue, 15 Jan 2019 15:06:13 -0500 From: "Michael S. Tsirkin" To: qemu-devel@nongnu.org Message-ID: <20190115200252.25911-46-mst@redhat.com> References: <20190115200252.25911-1-mst@redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20190115200252.25911-1-mst@redhat.com> X-Mutt-Fcc: =sent X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Tue, 15 Jan 2019 20:06:14 +0000 (UTC) Content-Transfer-Encoding: quoted-printable 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 v2 45/49] 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: Peter Maydell , Thomas Huth , Richard Henderson , Stefan Hajnoczi , Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" Content-Type: text/plain; charset="utf-8" From: Philippe Mathieu-Daud=C3=A9 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 ). In tandem of -Wstringop-truncation, the "nonstring" attribute was added: 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. From the GCC manual: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-A= ttributes.html#index-nonstring-variable-attribute Add the QEMU_NONSTRING macro which checks if the compiler supports this attribute. Suggested-by: Michael S. Tsirkin Reviewed-by: Eric Blake Reviewed-by: Michael S. Tsirkin Reviewed-by: Richard Henderson Reviewed-by: Thomas Huth 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 MST