1 files changed, 146 insertions, 0 deletions
diff --git a/sys/dev/null/null.c b/sys/dev/null/null.c
new file mode 100644
index 0000000..75f9a90
--- /dev/null
+++ b/sys/dev/null/null.c
@@ -0,0 +1,146 @@
+/*-
+ * Copyright (c) 2000 Mark R. V. Murray & Jeroen C. van Gelderen
+ * 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 AUTHORS ``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/conf.h>
+#include <sys/uio.h>
+#include <sys/kernel.h>
+#include <sys/malloc.h>
+#include <sys/module.h>
+#include <sys/disk.h>
+#include <sys/bus.h>
+#include <machine/bus.h>
+
+/* For use with destroy_dev(9). */
+static dev_t null_dev;
+static dev_t zero_dev;
+
+static d_write_t null_write;
+static d_ioctl_t null_ioctl;
+static d_read_t zero_read;
+static d_read_t null_read;
+
+#define CDEV_MAJOR	2
+#define NULL_MINOR	2
+#define ZERO_MINOR	12
+
+static struct cdevsw null_cdevsw = {
+	.d_open =	nullopen,
+	.d_close =	nullclose,
+	.d_read =	null_read,
+	.d_write =	null_write,
+	.d_ioctl =	null_ioctl,
+	.d_name =	"null",
+	.d_maj =	CDEV_MAJOR,
+};
+
+static struct cdevsw zero_cdevsw = {
+	.d_open =	nullopen,
+	.d_close =	nullclose,
+	.d_read =	zero_read,
+	.d_write =	null_write,
+	.d_name =	"zero",
+	.d_maj =	CDEV_MAJOR,
+	.d_flags =	D_MMAP_ANON,
+};
+
+static void *zbuf;
+
+static int
+null_read(dev_t dev __unused, struct uio *uio, int flags __unused)
+{
+
+	return 0;
+}
+
+/* ARGSUSED */
+static int
+null_write(dev_t dev __unused, struct uio *uio, int flags __unused)
+{
+	uio->uio_resid = 0;
+	return 0;
+}
+
+static int
+null_ioctl(dev_t dev, u_long cmd, caddr_t data, int flags, struct thread *td)
+{
+	int error;
+
+	if (cmd != DIOCSKERNELDUMP)
+		return (noioctl(dev, cmd, data, flags, td));
+	error = suser(td);
+	if (error)
+		return (error);
+	return (set_dumper(NULL));
+}
+
+/* ARGSUSED */
+static int
+zero_read(dev_t dev __unused, struct uio *uio, int flags __unused)
+{
+	int c;
+	int error = 0;
+
+	while (uio->uio_resid > 0 && error == 0) {
+		c = uio->uio_resid < PAGE_SIZE ? uio->uio_resid : PAGE_SIZE;
+		error = uiomove(zbuf, c, uio);
+	}
+	return error;
+}
+
+/* ARGSUSED */
+static int
+null_modevent(module_t mod __unused, int type, void *data __unused)
+{
+	switch(type) {
+	case MOD_LOAD:
+		if (bootverbose)
+			printf("null: <null device, zero device>\n");
+		zbuf = (void *)malloc(PAGE_SIZE, M_TEMP, M_WAITOK | M_ZERO);
+		zero_dev = make_dev(&zero_cdevsw, ZERO_MINOR, UID_ROOT,
+			GID_WHEEL, 0666, "zero");
+		null_dev = make_dev(&null_cdevsw, NULL_MINOR, UID_ROOT,
+			GID_WHEEL, 0666, "null");
+		return 0;
+
+	case MOD_UNLOAD:
+		destroy_dev(null_dev);
+		destroy_dev(zero_dev);
+		free(zbuf, M_TEMP);
+		return 0;
+
+	case MOD_SHUTDOWN:
+		return 0;
+
+	default:
+		return EOPNOTSUPP;
+	}
+}
+
+DEV_MODULE(null, null_modevent, NULL);