Initial Spring 2016 commit.

kern/dev/generic/random.c

@@ -0,0 +1,158 @@
+/*
+ * Copyright (c) 2000, 2001, 2002, 2003, 2004, 2005, 2008, 2009
+ *	The President and Fellows of Harvard College.
+ *
+ * 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.
+ * 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.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE UNIVERSITY AND CONTRIBUTORS ``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 UNIVERSITY OR CONTRIBUTORS 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.
+ */
+
+#include <types.h>
+#include <kern/errno.h>
+#include <kern/fcntl.h>
+#include <lib.h>
+#include <uio.h>
+#include <vfs.h>
+#include <generic/random.h>
+#include "autoconf.h"
+
+/*
+ * Machine-independent generic randomness device.
+ *
+ * Remembers something that's a random source, and provides random()
+ * and randmax() to the rest of the kernel.
+ *
+ * The kernel config mechanism can be used to explicitly choose which
+ * of the available random sources to use, if more than one is
+ * available.
+ */
+
+static struct random_softc *the_random = NULL;
+
+/*
+ * VFS device functions.
+ * open: allow reading only.
+ */
+static
+int
+randeachopen(struct device *dev, int openflags)
+{
+	(void)dev;
+
+	if (openflags != O_RDONLY) {
+		return EIO;
+	}
+
+	return 0;
+}
+
+/*
+ * VFS I/O function. Hand off to implementation.
+ */
+static
+int
+randio(struct device *dev, struct uio *uio)
+{
+	struct random_softc *rs = dev->d_data;
+
+	if (uio->uio_rw != UIO_READ) {
+		return EIO;
+	}
+
+	return rs->rs_read(rs->rs_devdata, uio);
+}
+
+/*
+ * VFS ioctl function.
+ */
+static
+int
+randioctl(struct device *dev, int op, userptr_t data)
+{
+	/*
+	 * We don't support any ioctls.
+	 */
+	(void)dev;
+	(void)op;
+	(void)data;
+	return EIOCTL;
+}
+
+static const struct device_ops random_devops = {
+	.devop_eachopen = randeachopen,
+	.devop_io = randio,
+	.devop_ioctl = randioctl,
+};
+
+/*
+ * Config function.
+ */
+int
+config_random(struct random_softc *rs, int unit)
+{
+	int result;
+
+	/* We use only the first random device. */
+	if (unit!=0) {
+		return ENODEV;
+	}
+
+	KASSERT(the_random==NULL);
+	the_random = rs;
+
+	rs->rs_dev.d_ops = &random_devops;
+	rs->rs_dev.d_blocks = 0;
+	rs->rs_dev.d_blocksize = 1;
+	rs->rs_dev.d_data = rs;
+
+	/* Add the VFS device structure to the VFS device list. */
+	result = vfs_adddev("random", &rs->rs_dev, 0);
+	if (result) {
+		return result;
+	}
+
+	return 0;
+}
+
+
+/*
+ * Random number functions exported to the rest of the kernel.
+ */
+
+uint32_t
+random(void)
+{
+	if (the_random==NULL) {
+		panic("No random device\n");
+	}
+	return the_random->rs_random(the_random->rs_devdata);
+}
+
+uint32_t
+randmax(void)
+{
+	if (the_random==NULL) {
+		panic("No random device\n");
+	}
+	return the_random->rs_randmax(the_random->rs_devdata);
+}