random_bytes improvements for FreeBSD (from 12.x serie)

giving the possiblity to pre-fill the buffer. A new getrandom
function was added for future version with a similar interface
than Linux's syscall.

Author: devnexen

ext/standard/random.c

@@ -33,8 +33,11 @@
 #ifdef __linux__
 # include <sys/syscall.h>
 #endif
-#if defined(__OpenBSD__) || defined(__NetBSD__)
+#if defined(__OpenBSD__) || defined(__NetBSD__) || defined(__FreeBSD__)
 # include <sys/param.h>
+# if __FreeBSD__ && __FreeBSD_version > 1200000
+    #include <sys/random.h>
+# endif
 #endif
 
 #ifdef ZTS
@@ -96,8 +99,8 @@ PHPAPI int php_random_bytes(void *bytes, size_t size, zend_bool should_throw)
 #else
 	size_t read_bytes = 0;
 	ssize_t n;
-#if defined(__linux__) && defined(SYS_getrandom)
-	/* Linux getrandom(2) syscall */
+#if (defined(__linux__) && defined(SYS_getrandom)) || (defined(__FreeBSD__) && __FreeBSD_version >= 1200000)
+	/* Linux getrandom(2) syscall or FreeBSD getrandom(2) function*/
 	/* Keep reading until we get enough entropy */
 	while (read_bytes < size) {
 		/* Below, (bytes + read_bytes)  is pointer arithmetic.
@@ -110,7 +113,11 @@ PHPAPI int php_random_bytes(void *bytes, size_t size, zend_bool should_throw)
 
 		*/
 		size_t amount_to_read = size - read_bytes;
+#if defined(__linux__)
 		n = syscall(SYS_getrandom, bytes + read_bytes, amount_to_read, 0);
+#else
+		n = getrandom(bytes + read_bytes, amount_to_read, 0);
+#endif
 
 		if (n == -1) {
 			if (errno == ENOSYS) {