2 * Copyright (c) 2000 Mark R. V. Murray & Jeroen C. van Gelderen
3 * Copyright (c) 2001-2004 Mark R. V. Murray
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer
11 * in this position and unchanged.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
32 #include <sys/param.h>
33 #include <sys/systm.h>
36 #include <sys/kernel.h>
37 #include <sys/malloc.h>
38 #include <sys/module.h>
42 #include <sys/filio.h>
44 #include <machine/bus.h>
45 #include <machine/vmparam.h>
47 /* For use with destroy_dev(9). */
48 static struct cdev *null_dev;
49 static struct cdev *zero_dev;
51 static d_write_t null_write;
52 static d_ioctl_t null_ioctl;
53 static d_ioctl_t zero_ioctl;
54 static d_read_t zero_read;
56 static struct cdevsw null_cdevsw = {
57 .d_version = D_VERSION,
58 .d_read = (d_read_t *)nullop,
59 .d_write = null_write,
60 .d_ioctl = null_ioctl,
64 static struct cdevsw zero_cdevsw = {
65 .d_version = D_VERSION,
67 .d_write = null_write,
68 .d_ioctl = zero_ioctl,
70 .d_flags = D_MMAP_ANON,
75 null_write(struct cdev *dev __unused, struct uio *uio, int flags __unused)
84 null_ioctl(struct cdev *dev __unused, u_long cmd, caddr_t data __unused,
85 int flags __unused, struct thread *td)
92 error = priv_check(td, PRIV_SETDUMPER);
94 error = set_dumper(NULL, NULL);
99 if (*(int *)data != 0)
110 zero_ioctl(struct cdev *dev __unused, u_long cmd, caddr_t data __unused,
111 int flags __unused, struct thread *td)
120 if (*(int *)data != 0)
132 zero_read(struct cdev *dev __unused, struct uio *uio, int flags __unused)
138 KASSERT(uio->uio_rw == UIO_READ,
139 ("Can't be in %s for write", __func__));
140 zbuf = __DECONST(void *, zero_region);
141 while (uio->uio_resid > 0 && error == 0) {
142 len = uio->uio_resid;
143 if (len > ZERO_REGION_SIZE)
144 len = ZERO_REGION_SIZE;
145 error = uiomove(zbuf, len, uio);
153 null_modevent(module_t mod __unused, int type, void *data __unused)
158 printf("null: <null device, zero device>\n");
159 null_dev = make_dev_credf(MAKEDEV_ETERNAL_KLD, &null_cdevsw, 0,
160 NULL, UID_ROOT, GID_WHEEL, 0666, "null");
161 zero_dev = make_dev_credf(MAKEDEV_ETERNAL_KLD, &zero_cdevsw, 0,
162 NULL, UID_ROOT, GID_WHEEL, 0666, "zero");
166 destroy_dev(null_dev);
167 destroy_dev(zero_dev);
180 DEV_MODULE(null, null_modevent, NULL);
181 MODULE_VERSION(null, 1);