From 162db1352389dcc1c8d4154ddc65cbe76ff87a1c Mon Sep 17 00:00:00 2001
From: counterpoint <counterpoint@aliro.org>
Date: Wed, 26 Aug 2015 15:43:43 +0100
Subject: [PATCH] Add actual random number generation code.

---
 server/core/random.c    | 97 +++++++++++++++++++++++++++++++++++++++++
 server/include/random.h | 22 ++++++++++
 2 files changed, 119 insertions(+)
 create mode 100644 server/core/random.c
 create mode 100644 server/include/random.h

diff --git a/server/core/random.c b/server/core/random.c
new file mode 100644
index 000000000..bba20ade5
--- /dev/null
+++ b/server/core/random.c
@@ -0,0 +1,97 @@
+/*
+ * This file is distributed as part of the MariaDB Corporation MaxScale.  It is free
+ * software: you can redistribute it and/or modify it under the terms of the
+ * GNU General Public License as published by the Free Software Foundation,
+ * version 2.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 51
+ * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Copyright MariaDB Corporation Ab 2013-2014
+ */
+
+/**
+ * @file random.c  -  Random number generator for the MariaDB Corporation MaxScale
+ *
+ * @verbatim
+ * Revision History
+ *
+ * Date		Who		Description
+ * 26/08/15	Martin Brampton	Initial implementation
+ *
+ * @endverbatim
+ */
+
+#include <stdbool.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <random.h>
+
+/* Public domain code for JKISS RNG - Comments added */
+static unsigned int x = 123456789,y = 987654321,z = 43219876,c = 6543217; /* Seed variables */
+static bool init = false;
+
+/***
+ * 
+ * Return a random number
+ * 
+ * @return  uint    Random number
+ * 
+ */
+unsigned int 
+random_jkiss(void)
+{
+    unsigned long long t;
+    if (!init) random_init_jkiss();
+    x = 314527869 * x + 1234567;
+    y ^= y << 5; y ^= y >> 7; y ^= y << 22;
+    t = 4294584393ULL * z + c; c = t >> 32; z = t;
+    return x + y + z;
+}
+
+/* Own code adapted from http://www0.cs.ucl.ac.uk/staff/d.jones/GoodPracticeRNG.pdf */
+
+/***
+ * 
+ * Obtain a seed random number from /dev/urandom if available.
+ * Otherwise use constant values
+ * 
+ * @return  uint    Random number
+ * 
+ */
+static unsigned int 
+random_devrand()
+{
+    int fn;
+    unsigned int r;
+    fn = open("/dev/urandom", O_RDONLY);
+    if (fn == -1) return 0;
+    if (read(fn, &r, 4) != 4) return 0;
+    close(fn);
+    return r;
+}
+
+/***
+ * 
+ * Initialise the generator using /dev/urandom if available, and warm up
+ * with 1000 iterations
+ * 
+ */
+static void
+random_init_jkiss()
+{
+    int newrand, i;
+    if ((newrand = random_devrand()) != 0) x = newrand;
+    if ((newrand = random_devrand()) != 0) y = newrand;
+    if ((newrand = random_devrand()) != 0) z = newrand;
+    if ((newrand = random_devrand()) != 0) 
+        c = newrand % 698769068 + 1; /* Should be less than 698769069 */
+    for (i = 0; i < 1000; i++) random_jkiss();
+}
\ No newline at end of file
diff --git a/server/include/random.h b/server/include/random.h
new file mode 100644
index 000000000..b302594d2
--- /dev/null
+++ b/server/include/random.h
@@ -0,0 +1,22 @@
+/* 
+ * File:   random.h
+ * Author: mbrampton
+ *
+ * Created on 26 August 2015, 15:34
+ */
+
+#ifndef RANDOM_H
+#define	RANDOM_H
+
+#ifdef	__cplusplus
+extern "C" {
+#endif
+
+unsigned int random_jkiss(void);
+    
+#ifdef	__cplusplus
+}
+#endif
+
+#endif	/* RANDOM_H */
+