From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:59052 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1950213AbcHRO2b (ORCPT ); Thu, 18 Aug 2016 10:28:31 -0400 From: Jeff Layton To: libc-alpha@sourceware.org Cc: linux-fsdevel@vger.kernel.org, chrubis@suse.cz, Mike Frysinger Subject: [glibc PATCHv2] fcntl-linux.h: add F_OFD_*32 constants Date: Thu, 18 Aug 2016 10:28:27 -0400 Message-Id: <1471530507-6484-1-git-send-email-jlayton@redhat.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: 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. Mike suggests that we also define *64 versions of the constants, and always define the "bare" ones based on those for clarity. Reported-by: Cyril Hrubis Cc: Mike Frysinger Signed-off-by: Jeff Layton --- ChangeLog | 5 +++++ sysdeps/unix/sysv/linux/bits/fcntl-linux.h | 20 ++++++++++++++++---- 2 files changed, 21 insertions(+), 4 deletions(-) diff --git a/ChangeLog b/ChangeLog index 59c68d8b9d0d..cf1561d6a373 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,8 @@ +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..f9e02d8354cf 100644 --- a/sysdeps/unix/sysv/linux/bits/fcntl-linux.h +++ b/sysdeps/unix/sysv/linux/bits/fcntl-linux.h @@ -127,11 +127,23 @@ 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 +# define F_OFD_GETLK64 36 +# define F_OFD_SETLK64 37 +# define F_OFD_SETLKW64 38 +# define F_OFD_GETLK32 39 +# define F_OFD_SETLK32 40 +# define F_OFD_SETLKW32 41 +# if __OFF_T_MATCHES_OFF64_T || defined __USE_FILE_OFFSET64 +# define F_OFD_GETLK F_OFD_GETLK64 +# define F_OFD_SETLK F_OFD_SETLK64 +# define F_OFD_SETLKW F_OFD_SETLKW64 +# else +# 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 -- 2.7.4