tunables: Use direct syscall for access (BZ#21744)

The function maybe_enable_malloc_check, which is called by
__tunables_init, calls __access_noerrno.  It isn't problem when
symbol is is in ld.so, which has a special version of __access_noerrno
without stack protector.  But when glibc is built with stack protector,
maybe_enable_malloc_check in libc.a can't call the regular version of
__access_noerrno with stack protector.

This patch changes how Linux defines the __access_noerrno to be an
inline call instead and thus preventing defining different build
rules for ld/static and shared.

	H.J. Lu  <hongjiu.lu@intel.com>
	Adhemerval Zanella  <adhemerval.zanella@linaro.org>

	[BZ #21744]
	* elf/dl-tunables.c: Include not-errno.h header.
	* include/unistd.h (__access_noerrno): Remove definition.
	* sysdeps/unix/sysv/linux/access.c (__access_noerrno): Likewise.
	* sysdeps/generic/not-errno.h: New file.
	* sysdeps/unix/sysv/linux/not-errno.h: Likewise.

1 files changed, 19 insertions, 0 deletions

diff --git a/sysdeps/generic/not-errno.h b/sysdeps/generic/not-errno.h
new file mode 100644
index 0000000000..2aac095e71
--- /dev/null
+++ b/sysdeps/generic/not-errno.h
@@ -0,0 +1,19 @@
+/* Syscall wrapper that do not set errno.  Generic version.
+   Copyright (C) 2017 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/>.  */
+
+extern __typeof (__access) __access_noerrno attribute_hidden;