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devnull.c revision 1.1.4.3 
      1  1.1.4.3  yamt /*	$NetBSD: devnull.c,v 1.1.4.3 2010/08/11 22:55:08 yamt Exp $	*/
      2  1.1.4.2  yamt 
      3  1.1.4.2  yamt /*
      4  1.1.4.2  yamt  * Copyright (c) 2009 Antti Kantee.  All Rights Reserved.
      5  1.1.4.2  yamt  *
      6  1.1.4.2  yamt  * Redistribution and use in source and binary forms, with or without
      7  1.1.4.2  yamt  * modification, are permitted provided that the following conditions
      8  1.1.4.2  yamt  * are met:
      9  1.1.4.2  yamt  * 1. Redistributions of source code must retain the above copyright
     10  1.1.4.2  yamt  *    notice, this list of conditions and the following disclaimer.
     11  1.1.4.2  yamt  * 2. Redistributions in binary form must reproduce the above copyright
     12  1.1.4.2  yamt  *    notice, this list of conditions and the following disclaimer in the
     13  1.1.4.2  yamt  *    documentation and/or other materials provided with the distribution.
     14  1.1.4.2  yamt  *
     15  1.1.4.2  yamt  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
     16  1.1.4.2  yamt  * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
     17  1.1.4.2  yamt  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
     18  1.1.4.2  yamt  * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     19  1.1.4.2  yamt  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     20  1.1.4.2  yamt  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
     21  1.1.4.2  yamt  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     22  1.1.4.2  yamt  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     23  1.1.4.2  yamt  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     24  1.1.4.2  yamt  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     25  1.1.4.2  yamt  * SUCH DAMAGE.
     26  1.1.4.2  yamt  */
     27  1.1.4.2  yamt 
     28  1.1.4.2  yamt /*
     29  1.1.4.2  yamt  * /dev/null, the infamous bytesink.
     30  1.1.4.2  yamt  *
     31  1.1.4.2  yamt  * I can't imagine it being very different in the rump kernel than in
     32  1.1.4.2  yamt  * the host kernel.  But nonetheless it serves as a simple example.
     33  1.1.4.2  yamt  */
     34  1.1.4.2  yamt 
     35  1.1.4.2  yamt #include <sys/cdefs.h>
     36  1.1.4.3  yamt __KERNEL_RCSID(0, "$NetBSD: devnull.c,v 1.1.4.3 2010/08/11 22:55:08 yamt Exp $");
     37  1.1.4.2  yamt 
     38  1.1.4.2  yamt #include <sys/param.h>
     39  1.1.4.2  yamt #include <sys/conf.h>
     40  1.1.4.2  yamt #include <sys/device.h>
     41  1.1.4.2  yamt #include <sys/stat.h>
     42  1.1.4.2  yamt 
     43  1.1.4.2  yamt #include "rump_vfs_private.h"
     44  1.1.4.2  yamt 
     45  1.1.4.2  yamt static dev_type_open(rump_devnullopen);
     46  1.1.4.2  yamt static dev_type_read(rump_devnullrw);
     47  1.1.4.2  yamt 
     48  1.1.4.2  yamt static struct cdevsw null_cdevsw = {
     49  1.1.4.2  yamt 	rump_devnullopen, nullclose, rump_devnullrw, rump_devnullrw, noioctl,
     50  1.1.4.2  yamt 	nostop, notty, nopoll, nommap, nokqfilter, D_OTHER | D_MPSAFE,
     51  1.1.4.2  yamt };
     52  1.1.4.2  yamt 
     53  1.1.4.2  yamt int
     54  1.1.4.2  yamt rump_devnull_init()
     55  1.1.4.2  yamt {
     56  1.1.4.3  yamt 	devmajor_t null_bmaj, null_cmaj;
     57  1.1.4.2  yamt 	int error;
     58  1.1.4.2  yamt 
     59  1.1.4.2  yamt 	null_bmaj = null_cmaj = NODEVMAJOR;
     60  1.1.4.2  yamt 	error = devsw_attach("null", NULL, &null_bmaj, &null_cdevsw,&null_cmaj);
     61  1.1.4.3  yamt 	KASSERT(error || null_cmaj == 2);
     62  1.1.4.2  yamt 
     63  1.1.4.3  yamt 	return error;
     64  1.1.4.2  yamt }
     65  1.1.4.2  yamt 
     66  1.1.4.2  yamt static int
     67  1.1.4.2  yamt rump_devnullopen(dev_t dev, int flag, int mode, struct lwp *l)
     68  1.1.4.2  yamt {
     69  1.1.4.2  yamt 
     70  1.1.4.2  yamt 	return 0;
     71  1.1.4.2  yamt }
     72  1.1.4.2  yamt 
     73  1.1.4.2  yamt static int
     74  1.1.4.2  yamt rump_devnullrw(dev_t dev, struct uio *uio, int flags)
     75  1.1.4.2  yamt {
     76  1.1.4.2  yamt 
     77  1.1.4.2  yamt 	if (uio->uio_rw == UIO_WRITE)
     78  1.1.4.2  yamt 		uio->uio_resid = 0;
     79  1.1.4.2  yamt 	return 0;
     80  1.1.4.2  yamt }
     81