From patchwork Tue Dec 18 11:03:32 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Philippe_Mathieu-Daud=C3=A9?= X-Patchwork-Id: 10735413 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 6E2C013BF for ; Tue, 18 Dec 2018 11:12:15 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 5EBB32A487 for ; Tue, 18 Dec 2018 11:12:15 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 5C5B82A5F9; Tue, 18 Dec 2018 11:12:15 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 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.wl.linuxfoundation.org (Postfix) with ESMTPS id CF79C2A487 for ; Tue, 18 Dec 2018 11:12:14 +0000 (UTC) Received: from localhost ([::1]:53125 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gZDIL-0004Av-Se for patchwork-qemu-devel@patchwork.kernel.org; Tue, 18 Dec 2018 06:12:13 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41250) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gZDEW-00015D-3t for qemu-devel@nongnu.org; Tue, 18 Dec 2018 06:08:17 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gZDBf-0000fg-Md for qemu-devel@nongnu.org; Tue, 18 Dec 2018 06:05:21 -0500 Received: from mx1.redhat.com ([209.132.183.28]:38168) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1gZDBZ-0000bu-J9; Tue, 18 Dec 2018 06:05:13 -0500 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id C1BE17FD50; Tue, 18 Dec 2018 11:05:12 +0000 (UTC) Received: from x1w.redhat.com (unknown [10.40.205.65]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 0A7D267E68; Tue, 18 Dec 2018 11:04:37 +0000 (UTC) From: =?utf-8?q?Philippe_Mathieu-Daud=C3=A9?= To: qemu-devel@nongnu.org Date: Tue, 18 Dec 2018 12:03:32 +0100 Message-Id: <20181218110333.22558-3-philmd@redhat.com> In-Reply-To: <20181218110333.22558-1-philmd@redhat.com> References: <20181218110333.22558-1-philmd@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Tue, 18 Dec 2018 11:05:13 +0000 (UTC) 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 v2 2/3] block/sheepdog: Replace strncpy() by strpadcpy(pad='\0') 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 , Paolo Bonzini , Ben Pye , qemu-block@nongnu.org, Juan Quintela , David Hildenbrand , Markus Armbruster , =?utf-8?q?Marc-Andr=C3=A9_Lureau?= , =?utf-8?q?Philippe_Mathieu-Daud=C3=A9?= , Thomas Huth , Stefan Weil , 1803872@bugs.launchpad.net, "Dr. David Alan Gilbert" , =?utf-8?q?C=C3=A9dric_Le_Goater?= , Liu Yuan , David Gibson , Kevin Wolf , Max Reitz , Howard Spoelstra , Igor Mammedov Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP 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=stringop-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); We could add a #pragma GCC diagnostic ignored "-Wstringop-truncation" around, disable the warning globally using -Wno-stringop-truncation, but since QEMU provides the strpadcpy() which does the same purpose, simply use it to avoid the annoying warning. Reported-by: Howard Spoelstra Buglink: https://bugs.launchpad.net/qemu/+bug/1803872 Signed-off-by: Philippe Mathieu-Daudé --- block/sheepdog.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/block/sheepdog.c b/block/sheepdog.c index 0125df9d49..72e1aef6ea 100644 --- a/block/sheepdog.c +++ b/block/sheepdog.c @@ -1231,12 +1231,12 @@ static int find_vdi_name(BDRVSheepdogState *s, const char *filename, return fd; } - /* This pair of strncpy calls ensures that the buffer is zero-filled, + /* This pair of strpadcpy 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); + strpadcpy(buf, SD_MAX_VDI_LEN, filename, '\0'); + strpadcpy(buf + SD_MAX_VDI_LEN, SD_MAX_VDI_TAG_LEN, tag, '\0'); memset(&hdr, 0, sizeof(hdr)); if (lock) {