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.

1 files changed, 3 insertions, 3 deletions

diff --git a/sysdeps/unix/sysv/linux/openat.c b/sysdeps/unix/sysv/linux/openat.c
index 5145823b8e..30d8e6e1ac 100644
--- a/sysdeps/unix/sysv/linux/openat.c
+++ b/sysdeps/unix/sysv/linux/openat.c
@@ -54,13 +54,13 @@ OPENAT_NOT_CANCEL (int fd, const char *file, int oflag, mode_t mode)
 
 
 /* Open FILE with access OFLAG.  Interpret relative paths relative to
-   the directory associated with FD.  If OFLAG includes O_CREAT, a
-   third argument is the file protection.  */
+   the directory associated with FD.  If OFLAG includes O_CREAT or
+   O_TMPFILE, a fourth argument is the file protection.  */
 int
 __OPENAT (int fd, const char *file, int oflag, ...)
 {
   mode_t mode = 0;
-  if (oflag & O_CREAT)
+  if (__OPEN_NEEDS_MODE (oflag))
     {
       va_list arg;
       va_start (arg, oflag);