[master] check for arc4random_addrandom()

3840.	[port]		Check for arc4random_addrandom() before using it;
			it's been removed from OpenBSD 5.5. [RT #35907]

CHANGES

@@ -1,3 +1,6 @@
+3840.	[port]		Check for arc4random_addrandom() before using it;
+			it's been removed from OpenBSD 5.5. [RT #35907]
+
 3839.	[test]		Use only posix-compatible shell in system tests.
 			[RT #35625]
 

acconfig.h

@@ -73,6 +73,9 @@
 /** define if arc4random() exists */
 #undef HAVE_ARC4RANDOM
 
+/** define if arc4random_addrandom() exists */
+#undef HAVE_ARC4RANDOM_ADDRANDOM
+
 /**
  * define if pthread_setconcurrency() should be called to tell the
  * OS how many threads we might want to run.

config.h.in

@@ -73,6 +73,9 @@
 /** define if arc4random() exists */
 #undef HAVE_ARC4RANDOM
 
+/** define if arc4random_addrandom() exists */
+#undef HAVE_ARC4RANDOM_ADDRANDOM
+
 /**
  * define if pthread_setconcurrency() should be called to tell the
  * OS how many threads we might want to run.

configure

@@ -14113,7 +14113,8 @@ fi
 
 
 #
-# Do we have arc4random() ?
+# Do we have arc4random(), etc ? arc4random_addrandom() has been removed
+# from OpenBSD 5.5 onwards.
 #
 ac_fn_c_check_func "$LINENO" "arc4random" "ac_cv_func_arc4random"
 if test "x$ac_cv_func_arc4random" = xyes; then :
@@ -14121,6 +14122,12 @@ if test "x$ac_cv_func_arc4random" = xyes; then :
 
 fi
 
+ac_fn_c_check_func "$LINENO" "arc4random_addrandom" "ac_cv_func_arc4random_addrandom"
+if test "x$ac_cv_func_arc4random_addrandom" = xyes; then :
+  $as_echo "#define HAVE_ARC4RANDOM_ADDRANDOM 1" >>confdefs.h
+
+fi
+
 
 #
 # Begin pthreads checking.

configure.in

@@ -967,9 +967,11 @@ fi
 AC_SUBST(CHECK_DSA)
 
 #
-# Do we have arc4random() ?
+# Do we have arc4random(), etc ? arc4random_addrandom() has been removed
+# from OpenBSD 5.5 onwards.
 #
 AC_CHECK_FUNC(arc4random, AC_DEFINE(HAVE_ARC4RANDOM))
+AC_CHECK_FUNC(arc4random_addrandom, AC_DEFINE(HAVE_ARC4RANDOM_ADDRANDOM))
 
 sinclude(config.threads.in)dnl
 

lib/isc/random.c

@@ -67,8 +67,16 @@ isc_random_seed(isc_uint32_t seed)
 
 #ifndef HAVE_ARC4RANDOM
 	srand(seed);
-#else
+#elif defined(HAVE_ARC4RANDOM_ADDRANDOM)
 	arc4random_addrandom((u_char *) &seed, sizeof(isc_uint32_t));
+#else
+	/*
+	 * If arcrandom() is available and no corresponding seeding
+	 * function arc4random_addrandom() is available, no seeding is
+	 * done on such platforms (e.g., OpenBSD 5.5). This is because
+	 * the OS itself is supposed to seed the RNG and it is assumed
+	 * that no explicit seeding is required.
+	 */
 #endif
 }