glibc/sysdeps/unix/sysv/linux/open64.c
Eric Rannaud 65f6f938cd linux: open and openat ignore 'mode' with O_TMPFILE in flags
Both open and openat load their last argument 'mode' lazily, using
va_arg() only if O_CREAT is found in oflag. This is wrong, mode is also
necessary if O_TMPFILE is in oflag.

By chance on x86_64, the problem wasn't evident when using O_TMPFILE
with open, as the 3rd argument of open, even when not loaded with
va_arg, is left untouched in RDX, where the syscall expects it.

However, openat was not so lucky, and O_TMPFILE couldn't be used: mode
is the 4th argument, in RCX, but the syscall expects its 4th argument in
a different register than the glibc wrapper, in R10.

Introduce a macro __OPEN_NEEDS_MODE (oflag) to test if either O_CREAT or
O_TMPFILE is set in oflag.

Tested on Linux x86_64.

	[BZ #17523]
	* io/fcntl.h (__OPEN_NEEDS_MODE): New macro.
	* io/bits/fcntl2.h (open): Use it.
	(openat): Likewise.
	* io/open.c (__libc_open): Likewise.
	* io/open64.c (__libc_open64): Likewise.
	* io/open64_2.c (__open64_2): Likewise.
	* io/open_2.c (__open_2): Likewise.
	* io/openat.c (__openat): Likewise.
	* io/openat64.c (__openat64): Likewise.
	* io/openat64_2.c (__openat64_2): Likewise.
	* io/openat_2.c (__openat_2): Likewise.
	* sysdeps/mach/hurd/open.c (__libc_open): Likewise.
	* sysdeps/mach/hurd/openat.c (__openat): Likewise.
	* sysdeps/posix/open64.c (__libc_open64): Likewise.
	* sysdeps/unix/sysv/linux/dl-openat64.c (openat64): Likewise.
	* sysdeps/unix/sysv/linux/generic/open.c (__libc_open): Likewise.
	(__open_nocancel): Likewise.
	* sysdeps/unix/sysv/linux/generic/open64.c (__libc_open64): Likewise.
	* sysdeps/unix/sysv/linux/open64.c (__libc_open64): Likewise.
	* sysdeps/unix/sysv/linux/openat.c (__OPENAT): Likewise.
2015-02-24 13:19:22 +05:30

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1.6 KiB
C

/* Copyright (C) 1991-2015 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <errno.h>
#include <fcntl.h>
#include <stdarg.h>
#include <stdio.h>
#include <sysdep-cancel.h>
/* Open FILE with access OFLAG. If O_CREAT or O_TMPFILE is in OFLAG,
a third argument is the file protection. */
int
__libc_open64 (const char *file, int oflag, ...)
{
int mode = 0;
if (__OPEN_NEEDS_MODE (oflag))
{
va_list arg;
va_start (arg, oflag);
mode = va_arg (arg, int);
va_end (arg);
}
if (SINGLE_THREAD_P)
return INLINE_SYSCALL (open, 3, file, oflag | O_LARGEFILE, mode);
int oldtype = LIBC_CANCEL_ASYNC ();
int result = INLINE_SYSCALL (open, 3, file, oflag | O_LARGEFILE, mode);
LIBC_CANCEL_RESET (oldtype);
return result;
}
weak_alias (__libc_open64, __open64)
libc_hidden_weak (__open64)
weak_alias (__libc_open64, open64)