* posix/bits/unistd.h (__readlinkat_chk): New prototype.

(__readlinkat_alias): New alias.
	(readlinkat): New inline function.
	* include/unistd.h (readlinkat): Add libc_hidden_proto.
	* sysdeps/unix/sysv/linux/readlinkat.c (readlinkat): Add
	libc_hidden_def.
	* io/readlinkat.c (readlinkat): Likewise.
	* debug/readlinkat_chk.c: New file.
	* debug/Makefile (routines): Add readlinkat_chk.
	* debug/Versions (libc): Export __readlinkat_chk@@GLIBC_2.5.
	* debug/tst-chk1.c (do_test): Add readlinkat tests.

	* nis/nss_nisplus/nisplus-netgrp.c: Cleanups.
	code is possible.  Move compatibility code in .text.compat section.
	over gaih array.  There is only one function to call in the moment.

debug/readlinkat_chk.c

@@ -0,0 +1,31 @@
+/* Copyright (C) 2006 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, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <unistd.h>
+#include <sys/param.h>
+
+
+ssize_t
+__readlinkat_chk (int fd, const char *path, void *buf, size_t len,
+		  size_t buflen)
+{
+  if (len > buflen)
+    __chk_fail ();
+
+  return readlinkat (fd, path, buf, len);
+}