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linux: open and openat ignore 'mode' with O_TMPFILE in flags

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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.
This commit is contained in:
Eric Rannaud
2015-02-24 13:12:26 +05:30
committed by Siddhesh Poyarekar
parent 3e3002ffea
commit 65f6f938cd
20 changed files with 81 additions and 47 deletions
Download Patch File Download Diff File Expand all files Collapse all files

6
sysdeps/unix/sysv/linux/generic/open.c
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@ -22,14 +22,14 @@
#include <stdio.h>
#include <sysdep-cancel.h>
/* Open FILE with access OFLAG. If OFLAG includes O_CREAT,
/* Open FILE with access OFLAG. If O_CREAT or O_TMPFILE is in OFLAG,
a third argument is the file protection. */
int
__libc_open (const char *file, int oflag, ...)
{
int mode = 0;
if (oflag & O_CREAT)
if (__OPEN_NEEDS_MODE (oflag))
{
va_list arg;
va_start (arg, oflag);
@ -59,7 +59,7 @@ __open_nocancel (const char *file, int oflag, ...)
{
int mode = 0;
if (oflag & O_CREAT)
if (__OPEN_NEEDS_MODE (oflag))
{
va_list arg;
va_start (arg, oflag);