Update.

	* sysdeps/unix/i386/i686/tempname.c: New file.

	* sysdeps/posix/tempname.c (__gen_tempname): If RANDOM_BITS is
	defined use this macro to get some bits of randomness instead of
	the usual gettimeofday or time calls.

2001-03-16  Paul Eggert  <eggert@twinsun.com>

	* sysdeps/posix/tempname.c (uint64_t): Define to uintmax_t if
	not defined, and if UINT64_MAX is not defined.

2001-03-19  Ulrich Drepper  <drepper@redhat.com>

ChangeLog

@@ -1,3 +1,16 @@
+2001-03-19  Ulrich Drepper  <drepper@redhat.com>
+
+	* sysdeps/unix/i386/i686/tempname.c: New file.
+
+	* sysdeps/posix/tempname.c (__gen_tempname): If RANDOM_BITS is
+	defined use this macro to get some bits of randomness instead of
+	the usual gettimeofday or time calls.
+
+2001-03-16  Paul Eggert  <eggert@twinsun.com>
+
+	* sysdeps/posix/tempname.c (uint64_t): Define to uintmax_t if
+	not defined, and if UINT64_MAX is not defined.
+
 2001-03-19  Ulrich Drepper  <drepper@redhat.com>
 
 	* elf/cache.c: Mark and have translated a few more messages.

manual/math.texi

@@ -1445,6 +1445,9 @@ c = 0xb = 11
 but they can also be changed by the user.  @code{m} is of course 2^48
 since the state consists of a 48-bit array.
 
+The prototypes for these functions are in @file{stdlib.h}.
+@pindex stdlib.h
+
 
 @comment stdlib.h
 @comment SVID

sysdeps/posix/tempname.c

@@ -107,6 +107,15 @@
 # define __secure_getenv getenv
 #endif
 
+/* Use the widest available unsigned type if uint64_t is not
+   available.  The algorithm below extracts a number less than 62**6
+   (approximately 2**35.725) from uint64_t, so ancient hosts where
+   uintmax_t is only 32 bits lose about 3.725 bits of randomness,
+   which is better than not having mkstemp at all.  */
+#if !defined UINT64_MAX && !defined uint64_t
+# define uint64_t uintmax_t
+#endif
+
 /* Return nonzero if DIR is an existent directory.  */
 static int
 direxists (const char *dir)
@@ -218,14 +227,18 @@ __gen_tempname (char *tmpl, int kind)
   XXXXXX = &tmpl[len - 6];
 
   /* Get some more or less random data.  */
-#if HAVE_GETTIMEOFDAY || _LIBC
+#ifdef RANDOM_BITS
+  RANDOM_BITS (random_time_bits);
+#else
+# if HAVE_GETTIMEOFDAY || _LIBC
   {
     struct timeval tv;
     __gettimeofday (&tv, NULL);
     random_time_bits = ((uint64_t) tv.tv_usec << 16) ^ tv.tv_sec;
   }
-#else
+# else
   random_time_bits = time (NULL);
+# endif
 #endif
   value += random_time_bits ^ __getpid ();
 

sysdeps/unix/i386/i686/tempname.c

@@ -0,0 +1,35 @@
+/* Copyright (C) 2001 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 Library General Public License as
+   published by the Free Software Foundation; either version 2 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
+   Library General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If not,
+   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+/* For i686 and up we have a better and faster source of random bits in the
+   form of the time stamp counter.  */
+#define RANDOM_BITS(Var) \
+  if (__builtin_expect (value == UINT64_C (0), 0))			      \
+    {									      \
+      /* If this is the first time this function is used initialize	      \
+	 the variable we accumulate the value in to some somewhat	      \
+	 random value.  If we'd not do this programs at startup time	      \
+	 might have a reduced set of possible names, at least on slow	      \
+	 machines.  */							      \
+      struct timeval tv;						      \
+      __gettimeofday (&tv, NULL);					      \
+      value = ((uint64_t) tv.tv_usec << 16) ^ tv.tv_sec;		      \
+    }									      \
+  __asm__ __volatile__ ("rdtsc" : "=A" (Var))
+
+#include_next <tempname.c>