138 lines
3.5 KiB
C
138 lines
3.5 KiB
C
/*-
|
|
* 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/bus.h>
|
|
#include <machine/bus.h>
|
|
#include <machine/resource.h>
|
|
#include <sys/rman.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_read_t zero_read;
|
|
|
|
#define CDEV_MAJOR 2
|
|
#define NULL_MINOR 2
|
|
#define ZERO_MINOR 12
|
|
|
|
static struct cdevsw null_cdevsw = {
|
|
/* open */ (d_open_t *)nullop,
|
|
/* close */ (d_close_t *)nullop,
|
|
/* read */ (d_read_t *)nullop,
|
|
/* write */ null_write,
|
|
/* ioctl */ noioctl,
|
|
/* poll */ nopoll,
|
|
/* mmap */ nommap,
|
|
/* strategy */ nostrategy,
|
|
/* name */ "null",
|
|
/* maj */ CDEV_MAJOR,
|
|
/* dump */ nodump,
|
|
/* psize */ nopsize,
|
|
/* flags */ 0,
|
|
/* bmaj */ -1
|
|
};
|
|
|
|
static struct cdevsw zero_cdevsw = {
|
|
/* open */ (d_open_t *)nullop,
|
|
/* close */ (d_close_t *)nullop,
|
|
/* read */ zero_read,
|
|
/* write */ null_write,
|
|
/* ioctl */ noioctl,
|
|
/* poll */ nopoll,
|
|
/* mmap */ nommap,
|
|
/* strategy */ nostrategy,
|
|
/* name */ "zero",
|
|
/* maj */ CDEV_MAJOR,
|
|
/* dump */ nodump,
|
|
/* psize */ nopsize,
|
|
/* flags */ D_MMAP_ANON,
|
|
/* bmaj */ -1
|
|
};
|
|
|
|
static void *zbuf;
|
|
|
|
static int
|
|
null_write(dev_t dev, struct uio *uio, int flag)
|
|
{
|
|
uio->uio_resid = 0;
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
zero_read(dev_t dev, struct uio *uio, int flag)
|
|
{
|
|
u_int c;
|
|
int error = 0;
|
|
|
|
while (uio->uio_resid > 0 && error == 0) {
|
|
c = min(uio->uio_resid, PAGE_SIZE);
|
|
error = uiomove(zbuf, c, uio);
|
|
}
|
|
return error;
|
|
}
|
|
|
|
static int
|
|
null_modevent(module_t mod, int type, void *data)
|
|
{
|
|
switch(type) {
|
|
case MOD_LOAD:
|
|
if (bootverbose)
|
|
printf("null: <null device, zero device>\n");
|
|
zbuf = (void *)malloc(PAGE_SIZE, M_TEMP, M_WAITOK);
|
|
bzero(zbuf, PAGE_SIZE);
|
|
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);
|