Preserve BC for rand() AND mt_rand() where min > max

5 files changed, 48 insertions, 12 deletions

diff --git a/ext/standard/basic_functions.c b/ext/standard/basic_functions.c
index ef03db14db..88e628ae05 100644
--- a/ext/standard/basic_functions.c
+++ b/ext/standard/basic_functions.c
@@ -2851,7 +2851,7 @@ const zend_function_entry basic_functions[] = { /* {{{ */
 	PHP_FE(proc_nice,														arginfo_proc_nice)
 #endif
 
-	PHP_FALIAS(rand, mt_rand,												arginfo_mt_rand)
+	PHP_FE(rand,															arginfo_mt_rand)
 	PHP_FALIAS(srand, mt_srand,												arginfo_mt_srand)
 	PHP_FALIAS(getrandmax, mt_getrandmax,									arginfo_mt_getrandmax)
 	PHP_FE(mt_rand,															arginfo_mt_rand)
diff --git a/ext/standard/mt_rand.c b/ext/standard/mt_rand.c
index f2866c5af2..dde9a77134 100644
--- a/ext/standard/mt_rand.c
+++ b/ext/standard/mt_rand.c
@@ -256,13 +256,31 @@ PHPAPI zend_long php_mt_rand_range(zend_long min, zend_long max)
 }
 /* }}} */
 
+/* {{{ php_mt_rand_common
+ * rand() allows min > max, mt_rand does not */
+PHPAPI zend_long php_mt_rand_common(zend_long min, zend_long max)
+{
+	zend_long n;
+
+	if (BG(mt_rand_mode) == MT_RAND_MT19937) {
+		return php_mt_rand_range(min, max);
+	}
+
+	/* Legacy mode deliberately not inside php_mt_rand_range()
+	 * to prevent other functions being affected */
+	n = (zend_long)php_mt_rand() >> 1;
+	RAND_RANGE_BADSCALING(n, min, max, PHP_MT_RAND_MAX);
+
+	return n;
+}
+/* }}} */
+
 /* {{{ proto int mt_rand([int min, int max])
    Returns a random number from Mersenne Twister */
 PHP_FUNCTION(mt_rand)
 {
 	zend_long min;
 	zend_long max;
-	zend_long n;
 	int argc = ZEND_NUM_ARGS();
 
 	if (argc == 0) {
@@ -276,18 +294,10 @@ PHP_FUNCTION(mt_rand)
 
 	if (UNEXPECTED(max < min)) {
 		php_error_docref(NULL, E_WARNING, "max(" ZEND_LONG_FMT ") is smaller than min(" ZEND_LONG_FMT ")", max, min);
-		max ^= min ^= max ^= min;
+		RETURN_FALSE;
 	}
 
-	if (BG(mt_rand_mode) == MT_RAND_MT19937) {
-		RETURN_LONG(php_mt_rand_range(min, max));
-	}
-
-	/* Legacy mode deliberately not inside php_mt_rand_range()
-	 * to prevent other functions being affected */
-	n = (zend_long)php_mt_rand() >> 1;
-	RAND_RANGE_BADSCALING(n, min, max, PHP_MT_RAND_MAX);
-	RETURN_LONG(n);
+	RETURN_LONG(php_mt_rand_common(min, max));
 }
 /* }}} */
 
diff --git a/ext/standard/php_math.h b/ext/standard/php_math.h
index 9798db8422..bc5b5125ee 100644
--- a/ext/standard/php_math.h
+++ b/ext/standard/php_math.h
@@ -45,6 +45,7 @@ PHP_FUNCTION(is_infinite);
 PHP_FUNCTION(is_nan);
 PHP_FUNCTION(pow);
 PHP_FUNCTION(sqrt);
+PHP_FUNCTION(rand);
 PHP_FUNCTION(mt_srand);
 PHP_FUNCTION(mt_rand);
 PHP_FUNCTION(mt_getrandmax);
diff --git a/ext/standard/php_mt_rand.h b/ext/standard/php_mt_rand.h
index bf0f6c20a1..e33d558591 100644
--- a/ext/standard/php_mt_rand.h
+++ b/ext/standard/php_mt_rand.h
@@ -36,6 +36,7 @@
 PHPAPI void php_mt_srand(uint32_t seed);
 PHPAPI uint32_t php_mt_rand(void);
 PHPAPI zend_long php_mt_rand_range(zend_long min, zend_long max);
+PHPAPI zend_long php_mt_rand_common(zend_long min, zend_long max);
 
 PHP_MINIT_FUNCTION(mt_rand);
 
diff --git a/ext/standard/rand.c b/ext/standard/rand.c
index 2720f55661..e97e0b46f0 100644
--- a/ext/standard/rand.c
+++ b/ext/standard/rand.c
@@ -45,6 +45,30 @@ PHPAPI zend_long php_rand(void)
 }
 /* }}} */
 
+/* {{{ proto int mt_rand([int min, int max])
+   Returns a random number from Mersenne Twister */
+PHP_FUNCTION(rand)
+{
+	zend_long min;
+	zend_long max;
+	int argc = ZEND_NUM_ARGS();
+
+	if (argc == 0) {
+		RETURN_LONG(php_mt_rand() >> 1);
+	}
+
+	if (zend_parse_parameters(argc, "ll", &min, &max) == FAILURE) {
+		return;
+	}
+
+	if (max < min) {
+		RETURN_LONG(php_mt_rand_common(max, min));
+	}
+
+	RETURN_LONG(php_mt_rand_common(min, max));
+}
+/* }}} */
+
 /*
  * Local variables:
  * tab-width: 4