Add range checking for FD_SET, FD_CLR, and FD_ISSET

misc/bits/select2.h

@@ -0,0 +1,34 @@
+/* Checking macros for select functions.
+   Copyright (C) 2011 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.  */
+
+#ifndef _SYS_SELECT_H
+# error "Never include <bits/select2.h> directly; use <sys/select.h> instead."
+#endif
+
+/* Helper functions to issue warnings and errors when needed.  */
+extern unsigned long int __fdelt_chk (unsigned long int __d);
+extern unsigned long int __fdelt_warn (unsigned long int __d)
+  __warnattr ("bit outside of fd_set selected");
+#undef __FDELT
+#define	__FDELT(d) \
+  ({ unsigned long int __d = d;						    \
+     (__builtin_constant_p (__d)					    \
+      ? (__d >= __FD_SETSIZE						    \
+	 ? __fdelt_warn (__d) : (__d / __NFDBITS))			    \
+      : __fdelt_chk (__d)); })