Hello. I have attached a very simple patch to add arc4random() to Bash for setting $RANDOM. It does not break the expected behavior of $RANDOM. It simply replaces getpid()+gettimeofday() with arc4random(). arc4random() is available on all BSD variants, and is used to get random numbers for non-cryptographic applications using little or no kernel entropy.
The behavior of being able to set 'RANDOM=1' to get a predictable number is unaffected by this patch. Please consider adding this patch so an uninitialized $RANDOM variable will be slightly better quality. robert
diff -Naur bash-3.2.orig/config.h.in bash-3.2/config.h.in
--- bash-3.2.orig/config.h.in 2006-09-12 20:00:54.000000000 +0000
+++ bash-3.2/config.h.in 2007-04-26 04:49:04.000000000 +0000
@@ -496,6 +496,9 @@
/* Presence of system and C library functions. */
+/* Define if you have the arc4random function. */
+#undef HAVE_ARC4RANDOM
+
/* Define if you have the asprintf function. */
#undef HAVE_ASPRINTF
diff -Naur bash-3.2.orig/configure bash-3.2/configure
--- bash-3.2.orig/configure 2006-09-26 15:06:01.000000000 +0000
+++ bash-3.2/configure 2007-04-26 04:53:44.000000000 +0000
@@ -14542,6 +14542,109 @@
+for ac_func in arc4random
+do
+as_ac_var=`echo "ac_cv_func_$ac_func" | $as_tr_sh`
+echo "$as_me:$LINENO: checking for $ac_func" >&5
+echo $ECHO_N "checking for $ac_func... $ECHO_C" >&6
+if eval "test \"\${$as_ac_var+set}\" = set"; then
+ echo $ECHO_N "(cached) $ECHO_C" >&6
+else
+ cat >conftest.$ac_ext <<_ACEOF
+/* confdefs.h. */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h. */
+/* Define $ac_func to an innocuous variant, in case <limits.h> declares $ac_func.
+ For example, HP-UX 11i <limits.h> declares gettimeofday. */
+#define $ac_func innocuous_$ac_func
+
+/* System header to define __stub macros and hopefully few prototypes,
+ which can conflict with char $ac_func (); below.
+ Prefer <limits.h> to <assert.h> if __STDC__ is defined, since
+ <limits.h> exists even on freestanding compilers. */
+
+#ifdef __STDC__
+# include <limits.h>
+#else
+# include <assert.h>
+#endif
+
+#undef $ac_func
+
+/* Override any gcc2 internal prototype to avoid an error. */
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+/* We use char because int might match the return type of a gcc2
+ builtin and then its argument prototype would still apply. */
+char $ac_func ();
+/* The GNU C library defines this for functions which it implements
+ to always fail with ENOSYS. Some functions are actually named
+ something starting with __ and the normal name is an alias. */
+#if defined (__stub_$ac_func) || defined (__stub___$ac_func)
+choke me
+#else
+char (*f) () = $ac_func;
+#endif
+#ifdef __cplusplus
+}
+#endif
+
+int
+main ()
+{
+return f != $ac_func;
+ ;
+ return 0;
+}
+_ACEOF
+rm -f conftest.$ac_objext conftest$ac_exeext
+if { (eval echo "$as_me:$LINENO: \"$ac_link\"") >&5
+ (eval $ac_link) 2>conftest.er1
+ ac_status=$?
+ grep -v '^ *+' conftest.er1 >conftest.err
+ rm -f conftest.er1
+ cat conftest.err >&5
+ echo "$as_me:$LINENO: \$? = $ac_status" >&5
+ (exit $ac_status); } &&
+ { ac_try='test -z "$ac_c_werror_flag"
+ || test ! -s conftest.err'
+ { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
+ (eval $ac_try) 2>&5
+ ac_status=$?
+ echo "$as_me:$LINENO: \$? = $ac_status" >&5
+ (exit $ac_status); }; } &&
+ { ac_try='test -s conftest$ac_exeext'
+ { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
+ (eval $ac_try) 2>&5
+ ac_status=$?
+ echo "$as_me:$LINENO: \$? = $ac_status" >&5
+ (exit $ac_status); }; }; then
+ eval "$as_ac_var=yes"
+else
+ echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+eval "$as_ac_var=no"
+fi
+rm -f conftest.err conftest.$ac_objext \
+ conftest$ac_exeext conftest.$ac_ext
+fi
+echo "$as_me:$LINENO: result: `eval echo '${'$as_ac_var'}'`" >&5
+echo "${ECHO_T}`eval echo '${'$as_ac_var'}'`" >&6
+if test `eval echo '${'$as_ac_var'}'` = yes; then
+ cat >>confdefs.h <<_ACEOF
+#define `echo "HAVE_$ac_func" | $as_tr_cpp` 1
+_ACEOF
+
+fi
+done
+
+
+
diff -Naur bash-3.2.orig/configure.in bash-3.2/configure.in
--- bash-3.2.orig/configure.in 2006-09-26 15:05:45.000000000 +0000
+++ bash-3.2/configure.in 2007-04-26 04:49:26.000000000 +0000
@@ -748,6 +748,9 @@
AC_FUNC_MKTIME
+dnl Checks for the arc4random function
+AC_CHECK_FUNCS(arc4random)
+
dnl
dnl Checks for lib/intl and related code (uses some of the output from
dnl AM_GNU_GETTEXT)
diff -Naur bash-3.2.orig/variables.c bash-3.2/variables.c
--- bash-3.2.orig/variables.c 2006-09-08 17:33:32.000000000 +0000
+++ bash-3.2/variables.c 2007-04-26 04:53:27.000000000 +0000
@@ -1188,7 +1188,11 @@
/* Reset for command and process substitution. */
if (subshell_environment && seeded_subshell == 0)
{
+#if defined(HAVE_ARC4RANDOM)
+ sbrand (arc4random());
+#else
sbrand (rseed + getpid() + NOW);
+#endif
seeded_subshell = 1;
}
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