This patch is from:
	http://cvs.fedoraproject.org/viewvc/devel/bash/bash-3.2-rng.patch
	http://cvs.fedoraproject.org/viewvc/devel/bash/bash-3.2-344411.patch

The second patch (bash-3.2-344411.patch) was integrated in bash-4.0, to provide
$RANDOM in sub shells.

Use /dev/urandom for $RANDOM. This patch does not break the Korn shell
behaviour, where we can initialize $RANDOM ourselves and get the same results
each time. /dev/urandom is only opened when $RANDOM is called.

I pulled out all the autoconf stuff. This patch depends on random(3) and
srandom(3) in libc, and /dev/urandom. getpid(3) and gettimeofday(3) are used
if /dev/urandom isn't available at run time (like in a chroot).

Test case:
( echo $RANDOM; ( echo $RANDOM ); ( echo $RANDOM ) )

robert

diff -Naur bash-4.0.orig/variables.c bash-4.0/variables.c
--- bash-4.0.orig/variables.c	2009-01-04 19:32:46.000000000 +0000
+++ bash-4.0/variables.c	2009-02-22 20:15:50.000000000 +0000
@@ -44,6 +44,12 @@
 #include "bashansi.h"
 #include "bashintl.h"
 
+#include <errno.h>
+#include "filecntl.h"
+#ifndef RANDOMDEV
+#define RANDOMDEV "/dev/urandom"
+#endif
+
 #include "shell.h"
 #include "flags.h"
 #include "execute_cmd.h"
@@ -188,7 +194,7 @@
 static SHELL_VAR *init_seconds_var __P((void));
 
 static int brand __P((void));
-static void sbrand __P((unsigned long));		/* set bash random number generator. */
+static void sbrand __P((unsigned int));			/* set bash random number generator. */
 static void seedrand __P((void));			/* seed generator randomly */
 static SHELL_VAR *assign_random __P((SHELL_VAR *, char *, arrayind_t, char *));
 static SHELL_VAR *get_random __P((SHELL_VAR *));
@@ -518,9 +524,6 @@
     }
 #endif /* HISTORY */
 
-  /* Seed the random number generator. */
-  seedrand ();
-
   /* Handle some "special" variables that we may have inherited from a
      parent shell. */
   if (interactive_shell)
@@ -1204,9 +1207,8 @@
 }
      
 /* The random number seed.  You can change this by setting RANDOM. */
-static unsigned long rseed = 1;
 static int last_random_value;
-static int seeded_subshell = 0;
+static int seeded_subshell = -1;
 
 /* A linear congruential random number generator based on the example
    one in the ANSI C standard.  This one isn't very good, but a more
@@ -1216,44 +1218,36 @@
 static int
 brand ()
 {
-#if 0
-  rseed = rseed * 1103515245 + 12345;
-  return ((unsigned int)((rseed >> 16) & 32767));	/* was % 32768 */
-#else
-  /* From "Random number generators: good ones are hard to find",
-     Park and Miller, Communications of the ACM, vol. 31, no. 10,
-     October 1988, p. 1195. filtered through FreeBSD */
-  long h, l;
-
-  if (rseed == 0)
-    seedrand ();
-  h = rseed / 127773;
-  l = rseed % 127773;
-  rseed = 16807 * l - 2836 * h;
-#if 0
-  if (rseed < 0)
-    rseed += 0x7fffffff;
-#endif
+  unsigned int rseed;
+  rseed = random();
   return ((unsigned int)(rseed & 32767));	/* was % 32768 */
-#endif
 }
 
 /* Set the random number generator seed to SEED. */
 static void
 sbrand (seed)
-     unsigned long seed;
+     unsigned int seed;
 {
-  rseed = seed;
+  srandom((unsigned int)seed);
   last_random_value = 0;
 }
 
 static void
 seedrand ()
 {
-  struct timeval tv;
-
-  gettimeofday (&tv, NULL);
-  sbrand (tv.tv_sec ^ tv.tv_usec ^ getpid ());
+  unsigned int seed;
+  int fd;
+  int rv;
+  if ((rv = fd = open (RANDOMDEV, O_RDONLY)) != -1) {
+    while ((rv = read(fd, &seed, sizeof(seed))) != sizeof(seed) && errno == EINTR);
+    close (fd);
+  }
+  if (rv != sizeof(seed)) {
+    struct timeval tv;
+    gettimeofday (&tv, NULL);
+    seed = (unsigned int)tv.tv_sec + (unsigned int)tv.tv_usec + getpid();
+  }
+  sbrand (seed);
 }
 
 static SHELL_VAR *
@@ -1263,9 +1257,8 @@
      arrayind_t unused;
      char *key;
 {
-  sbrand (strtoul (value, (char **)NULL, 10));
-  if (subshell_environment)
-    seeded_subshell = getpid ();
+  sbrand ((unsigned int)strtoul (value, (char **)NULL, 10));
+  seeded_subshell = getpid ();
   return (self);
 }
 
@@ -1276,7 +1269,7 @@
 
   /* Reset for command and process substitution. */
   pid = getpid ();
-  if (subshell_environment && seeded_subshell != pid)
+  if (seeded_subshell != pid)
     {
       seedrand ();
       seeded_subshell = pid;