105 lines
2.9 KiB
C
105 lines
2.9 KiB
C
/* $NetBSD: devnull.c,v 1.3 2011/02/10 11:01:31 pooka Exp $ */
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/*
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* Copyright (c) 2009 Antti Kantee. All Rights Reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
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* OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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/*
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* /dev/null, the infamous bytesink.
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*
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* I can't imagine it being very different in the rump kernel than in
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* the host kernel. But nonetheless it serves as a simple example.
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: devnull.c,v 1.3 2011/02/10 11:01:31 pooka Exp $");
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#include <sys/param.h>
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#include <sys/conf.h>
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#include <sys/device.h>
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#include <sys/stat.h>
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#include "rump_vfs_private.h"
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static dev_type_open(rump_devnullopen);
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static dev_type_read(rump_devnullrw);
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static struct cdevsw null_cdevsw = {
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rump_devnullopen, nullclose, rump_devnullrw, rump_devnullrw, noioctl,
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nostop, notty, nopoll, nommap, nokqfilter, D_OTHER | D_MPSAFE,
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};
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int
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rump_devnull_init()
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{
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devmajor_t null_bmaj, null_cmaj;
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int error;
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null_bmaj = null_cmaj = NODEVMAJOR;
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error = devsw_attach("null", NULL, &null_bmaj, &null_cdevsw,&null_cmaj);
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KASSERT(error || null_cmaj == 2);
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return error;
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}
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static int
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rump_devnullopen(dev_t dev, int flag, int mode, struct lwp *l)
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{
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if (minor(dev) == DEV_ZERO || minor(dev) == DEV_NULL)
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return 0;
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return ENXIO;
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}
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static int
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rump_devnullrw(dev_t dev, struct uio *uio, int flags)
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{
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char zeros[512];
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int error;
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switch (minor(dev)) {
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case DEV_NULL:
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if (uio->uio_rw == UIO_WRITE)
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uio->uio_resid = 0;
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break;
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case DEV_ZERO:
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if (uio->uio_rw == UIO_WRITE) {
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uio->uio_resid = 0;
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break;
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}
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memset(zeros, 0, sizeof(zeros));
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while (uio->uio_resid > 0) {
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error = uiomove(zeros,
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min(sizeof(zeros), uio->uio_resid), uio);
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if (error)
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return error;
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}
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break;
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default:
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return ENXIO; /* how? */
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}
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return 0;
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}
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