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: 14748 Received: (qmail 5310 invoked by alias); 18 Aug 2016 12:03:41 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Delivered-To: mailing list libc-alpha@sourceware.org Received: (qmail 4973 invoked by uid 89); 18 Aug 2016 12:03:38 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.4 required=5.0 tests=BAYES_00, RP_MATCHES_RCVD, SPF_HELO_PASS autolearn=ham version=3.3.2 spammy=D*linux.vnet.ibm.com, D*vnet.ibm.com, dbl64, dbl-64 X-HELO: mx1.redhat.com 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> 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