From nobody Tue Dec 16 11:04:33 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 1546505949851178.42572415368886; Thu, 3 Jan 2019 00:59:09 -0800 (PST) Received: from localhost ([127.0.0.1]:49824 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1geyqK-0004fQ-Nk for importer@patchew.org; Thu, 03 Jan 2019 03:59:08 -0500 Received: from eggs.gnu.org ([208.118.235.92]:47533) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1geyoa-0003Fr-NB for qemu-devel@nongnu.org; Thu, 03 Jan 2019 03:57:21 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1geyoZ-0001Cs-P5 for qemu-devel@nongnu.org; Thu, 03 Jan 2019 03:57:20 -0500 Received: from mx1.redhat.com ([209.132.183.28]:48816) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1geyoX-00019M-LT; Thu, 03 Jan 2019 03:57:17 -0500 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id DC1143C2CC9; Thu, 3 Jan 2019 08:57:16 +0000 (UTC) Received: from x1w.redhat.com (unknown [10.40.205.99]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 1C9075D9C5; Thu, 3 Jan 2019 08:56:59 +0000 (UTC) From: =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= To: qemu-devel@nongnu.org Date: Thu, 3 Jan 2019 09:56:35 +0100 Message-Id: <20190103085638.17600-3-philmd@redhat.com> In-Reply-To: <20190103085638.17600-1-philmd@redhat.com> References: <20190103085638.17600-1-philmd@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.29]); Thu, 03 Jan 2019 08:57:16 +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 v5 2/5] block/sheepdog: Use QEMU_NONSTRING for non NUL-terminated arrays 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: Kevin Wolf , Thomas Huth , "open list:Sheepdog" , David Hildenbrand , Jeff Cody , "Michael S. Tsirkin" , "Dr. David Alan Gilbert" , Markus Armbruster , =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= , Paolo Bonzini , Igor Mammedov , Liu Yuan , Max Reitz , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" Content-Type: text/plain; charset="utf-8" GCC 8 added a -Wstringop-truncation warning: The -Wstringop-truncation warning added in GCC 8.0 via r254630 for bug 81117 is specifically intended to highlight likely unintended uses of the strncpy function that truncate the terminating NUL character from the source string. This new warning leads to compilation failures: CC block/sheepdog.o qemu/block/sheepdog.c: In function 'find_vdi_name': qemu/block/sheepdog.c:1239:5: error: 'strncpy' specified bound 256 equals= destination size [-Werror=3Dstringop-truncation] strncpy(buf + SD_MAX_VDI_LEN, tag, SD_MAX_VDI_TAG_LEN); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ make: *** [qemu/rules.mak:69: block/sheepdog.o] Error 1 As described previous to the strncpy() calls, the use of strncpy() is correct here: /* This pair of strncpy calls ensures that the buffer is zero-filled, * which is desirable since we'll soon be sending those bytes, and * don't want the send_req to read uninitialized data. */ strncpy(buf, filename, SD_MAX_VDI_LEN); strncpy(buf + SD_MAX_VDI_LEN, tag, SD_MAX_VDI_TAG_LEN); Use the QEMU_NONSTRING attribute, since this array is intended to store character arrays that do not necessarily contain a terminating NUL. Suggested-by: Michael S. Tsirkin Reviewed-by: Eric Blake Reviewed-by: Michael S. Tsirkin Signed-off-by: Philippe Mathieu-Daud=C3=A9 --- block/sheepdog.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/block/sheepdog.c b/block/sheepdog.c index 0125df9d49..5cd9618432 100644 --- a/block/sheepdog.c +++ b/block/sheepdog.c @@ -1224,7 +1224,7 @@ static int find_vdi_name(BDRVSheepdogState *s, const = char *filename, SheepdogVdiReq hdr; SheepdogVdiRsp *rsp =3D (SheepdogVdiRsp *)&hdr; unsigned int wlen, rlen =3D 0; - char buf[SD_MAX_VDI_LEN + SD_MAX_VDI_TAG_LEN]; + char buf[SD_MAX_VDI_LEN + SD_MAX_VDI_TAG_LEN] QEMU_NONSTRING; =20 fd =3D connect_to_sdog(s, errp); if (fd < 0) { --=20 2.17.2