From patchwork Thu Aug 18 12:03:35 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jeff Layton X-Patchwork-Id: 9287473 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 420B1600CB for ; Thu, 18 Aug 2016 12:03:38 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 33E8C28AB0 for ; Thu, 18 Aug 2016 12:03:38 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 2871528AE2; Thu, 18 Aug 2016 12:03:38 +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=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C5E7028AB0 for ; Thu, 18 Aug 2016 12:03:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753369AbcHRMDg (ORCPT ); Thu, 18 Aug 2016 08:03:36 -0400 Received: from mx1.redhat.com ([209.132.183.28]:41170 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752449AbcHRMDg (ORCPT ); Thu, 18 Aug 2016 08:03:36 -0400 Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 25E4D7F7AA; Thu, 18 Aug 2016 12:03:36 +0000 (UTC) Received: from tlielax.poochiereds.net (ovpn-116-26.rdu2.redhat.com [10.10.116.26]) by int-mx11.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u7IC3Z1C003809; Thu, 18 Aug 2016 08:03:35 -0400 From: Jeff Layton To: libc-alpha@sourceware.org Cc: linux-fsdevel@vger.kernel.org, chrubis@suse.cz Subject: [glibc PATCH] fcntl-linux.h: add F_OFD_*32 constants Date: Thu, 18 Aug 2016 08:03:35 -0400 Message-Id: <1471521815-4340-1-git-send-email-jlayton@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.24 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Thu, 18 Aug 2016 12:03:36 +0000 (UTC) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The original assumption with OFD lock support was that userland would always pass in a struct flock that has been set up for large file support (LFS). It's possible however for someone to build a 32-bit program without large file support, and still try to use OFD locks. If that happens then it will send a non-LFS struct flock to the kernel, which will then try to interpret it as a LFS one, which can cause unexpected results. My original idea was to just ensure that the build would fail in this case by not defining the F_OFD_* constants when LFS support was not enabled. Instead though, it's probably better long-term to just go ahead and support OFD locks with non-LFS struct flock. To do that without breaking programs that are already working, we add a set of F_OFD_*32 constants, and add the plumbing to the kernel to make those do the right thing. This patch adds the same constants to glibc, and has it redefine the "normal" F_OFD_* constants to their *32 equvalents when LFS support is not in use. Signed-off-by: Jeff Layton --- ChangeLog | 4 ++++ sysdeps/unix/sysv/linux/bits/fcntl-linux.h | 17 +++++++++++++---- 2 files changed, 17 insertions(+), 4 deletions(-) diff --git a/ChangeLog b/ChangeLog index 59c68d8b9d0d..4a2488b50054 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,7 @@ +2016-08-18 Jeff Layton + * sysdeps/unix/sysv/linux/bits/fcntl-linux.h: + Add F_OFD_GETLK32, F_OFD_SETLK32, F_OFD_SETLKW32 + 2016-08-18 Stefan Liebler * sysdeps/ieee754/dbl-64/k_rem_pio2.c (__kernel_rem_pio2): diff --git a/sysdeps/unix/sysv/linux/bits/fcntl-linux.h b/sysdeps/unix/sysv/linux/bits/fcntl-linux.h index 7e5b0aecdcb4..9cb1b5f6f3ec 100644 --- a/sysdeps/unix/sysv/linux/bits/fcntl-linux.h +++ b/sysdeps/unix/sysv/linux/bits/fcntl-linux.h @@ -127,11 +127,20 @@ This means that they are inherited across fork or clone with CLONE_FILES like BSD (flock) locks, and they are only released automatically when the last reference to the the file description against which they were acquired - is put. */ + is put. */ #ifdef __USE_GNU -# define F_OFD_GETLK 36 -# define F_OFD_SETLK 37 -# define F_OFD_SETLKW 38 +# if __OFF_T_MATCHES_OFF64_T || defined __USE_FILE_OFFSET64 +# define F_OFD_GETLK 36 +# define F_OFD_SETLK 37 +# define F_OFD_SETLKW 38 +# else +# define F_OFD_GETLK32 39 +# define F_OFD_SETLK32 40 +# define F_OFD_SETLKW32 41 +# define F_OFD_GETLK F_OFD_GETLK32 +# define F_OFD_SETLK F_OFD_SETLK32 +# define F_OFD_SETLKW F_OFD_SETLKW32 +# endif #endif #ifdef __USE_LARGEFILE64