Compile random_jkiss.c as C++

server/core/random_jkiss.cc

@@ -0,0 +1,109 @@
+/*
+ * Copyright (c) 2016 MariaDB Corporation Ab
+ *
+ * Use of this software is governed by the Business Source License included
+ * in the LICENSE.TXT file and at www.mariadb.com/bsl11.
+ *
+ * Change Date: 2019-07-01
+ *
+ * On the date above, in accordance with the Business Source License, use
+ * of this software will be governed by version 2 or later of the General
+ * Public License.
+ */
+
+/**
+ * @file random_jkiss.c  -  Random number generator for the MariaDB Corporation MaxScale
+ *
+ * See http://www0.cs.ucl.ac.uk/staff/d.jones/GoodPracticeRNG.pdf for discussion of random
+ * number generators (RNGs).
+ */
+
+#include <stdbool.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <maxscale/random_jkiss.h>
+#include <maxscale/debug.h>
+
+/* Public domain code for JKISS RNG - Comment header added */
+
+/* If possible, the seed variables will be set from /dev/urandom but
+ * should that fail, these arbitrary numbers will be used as a last resort.
+ */
+static unsigned int x = 123456789, y = 987654321, z = 43219876, c = 6543217; /* Seed variables */
+static bool init = false;
+
+unsigned int random_jkiss(void)
+{
+    unsigned long long t;
+    unsigned int result;
+    ss_dassert(init);
+
+    x = 314527869 * x + 1234567;
+    y ^= y << 5;
+    y ^= y >> 7;
+    y ^= y << 22;
+    t = 4294584393ULL * z + c;
+    c = t >> 32;
+    z = t;
+    result = x + y + z;
+    return result;
+}
+
+/* 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.
+ *
+ * @return  uint    Random number
+ *
+ */
+static unsigned int random_jkiss_devrand(void)
+{
+    int fn;
+    unsigned int r;
+
+    if ((fn = open("/dev/urandom", O_RDONLY)) == -1)
+    {
+        return 0;
+    }
+
+    if (read(fn, &r, sizeof(r)) != sizeof(r))
+    {
+        r = 0;
+    }
+    close(fn);
+    return r;
+}
+
+void random_jkiss_init(void)
+{
+    if (!init)
+    {
+        int newrand, i;
+
+        if ((newrand = random_jkiss_devrand()) != 0)
+        {
+            x = newrand;
+        }
+
+        if ((newrand = random_jkiss_devrand()) != 0)
+        {
+            y = newrand;
+        }
+
+        if ((newrand = random_jkiss_devrand()) != 0)
+        {
+            z = newrand;
+        }
+
+        if ((newrand = random_jkiss_devrand()) != 0)
+        {
+            c = newrand % 698769068 + 1; /* Should be less than 698769069 */
+        }
+
+        init = true;
+    }
+}