1 files changed, 137 insertions, 0 deletions
diff --git a/sys/dev/random/harvest.c b/sys/dev/random/harvest.c
new file mode 100644
index 0000000..b6f3fba
--- /dev/null
+++ b/sys/dev/random/harvest.c
@@ -0,0 +1,137 @@
+/*-
+ * Copyright (c) 2000 Mark R V Murray
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer
+ *    in this position and unchanged.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/types.h>
+#include <sys/queue.h>
+#include <sys/kthread.h>
+#include <sys/lock.h>
+#include <sys/mutex.h>
+#include <sys/poll.h>
+#include <sys/selinfo.h>
+#include <sys/sysctl.h>
+#include <sys/random.h>
+
+#include <machine/cpu.h>
+
+#include <dev/random/randomdev.h>
+
+static int read_random_phony(void *, int);
+
+/* Structure holding the desired entropy sources */
+struct harvest_select harvest = { 0, 0, 0 };
+
+/* hold the address of the routine which is actually called if
+ * the randomdev is loaded
+ */
+static void (*reap_func)(u_int64_t, void *, u_int, u_int, u_int, enum esource)
+    = NULL;
+static int (*read_func)(void *, int) = read_random_phony;
+
+/* Initialise the harvester at load time */
+void
+random_init_harvester(void (*reaper)(u_int64_t, void *, u_int, u_int, u_int,
+    enum esource), int (*reader)(void *, int))
+{
+	reap_func = reaper;
+	read_func = reader;
+}
+
+/* Deinitialise the harvester at unload time */
+void
+random_deinit_harvester(void)
+{
+	reap_func = NULL;
+	read_func = read_random_phony;
+}
+
+/* Entropy harvesting routine. This is supposed to be fast; do
+ * not do anything slow in here!
+ * Implemented as in indirect call to allow non-inclusion of
+ * the entropy device.
+ */
+void
+random_harvest(void *entropy, u_int count, u_int bits, u_int frac,
+    enum esource origin)
+{
+	if (reap_func)
+		(*reap_func)(get_cyclecount(), entropy, count, bits, frac,
+		    origin);
+}
+
+/* Userland-visible version of read_random */
+int
+read_random(void *buf, int count)
+{
+	return (*read_func)(buf, count);
+}
+
+/* If the entropy device is not loaded, make a token effort to
+ * provide _some_ kind of randomness. This should only be used
+ * inside other RNG's, like arc4random(9).
+ */
+static int
+read_random_phony(void *buf, int count)
+{
+	u_long randval;
+	int size, i;
+	static int initialised = 0;
+
+	/* Try to give random(9) a half decent initialisation
+	 * DO NOT make the mistake of thinking this is secure!!
+	 */
+	if (!initialised)
+		srandom((u_long)get_cyclecount());
+
+	/* Fill buf[] with random(9) output */
+	for (i = 0; i < count; i+= (int)sizeof(u_long)) {
+		randval = random();
+		size = (count - i) < (int)sizeof(u_long)
+		    ? (count - i)
+		    : sizeof(u_long);
+		memcpy(&((char *)buf)[i], &randval, (size_t)size);
+	}
+
+	return count;
+}
+
+/* Helper routine to enable kthread_exit() to work while the module is
+ * being (or has been) unloaded.
+ * This routine is in this file because it is always linked into the kernel,
+ * and will thus never be unloaded. This is critical for unloadable modules
+ * that have threads.
+ */
+void
+random_set_wakeup_exit(void *control)
+{
+	wakeup(control);
+	mtx_lock(&Giant);
+	kthread_exit(0);
+	/* NOTREACHED */
+}