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freebsd/sys/dev/null/null.c
Poul-Henning Kamp 7ac40f5f59 Gigacommit to improve device-driver source compatibility between
branches:

Initialize struct cdevsw using C99 sparse initializtion and remove
all initializations to default values.

This patch is automatically generated and has been tested by compiling
LINT with all the fields in struct cdevsw in reverse order on alpha,
sparc64 and i386.

Approved by:    re(scottl)
2003-03-03 12:15:54 +00:00

147 lines
3.6 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/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);