kern_conf.c revision 46676 
1/*-
2 * Parts Copyright (c) 1995 Terrence R. Lambert
3 * Copyright (c) 1995 Julian R. Elischer
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 * 3. All advertising materials mentioning features or use of this software
15 *    must display the following acknowledgement:
16 *      This product includes software developed by Terrence R. Lambert.
17 * 4. The name Terrence R. Lambert may not be used to endorse or promote
18 *    products derived from this software without specific prior written
19 *    permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY Julian R. Elischer ``AS IS'' AND ANY
22 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE TERRENCE R. LAMBERT BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
33 * $Id: kern_conf.c,v 1.32 1999/05/07 10:10:50 phk Exp $
34 */
35
36#include <sys/param.h>
37#include <sys/systm.h>
38#include <sys/module.h>
39#include <sys/conf.h>
40#include <sys/vnode.h>
41
42#define NUMCDEV 256
43#define cdevsw_ALLOCSTART	(NUMCDEV/2)
44
45struct cdevsw 	*cdevsw[NUMCDEV];
46int	nchrdev = NUMCDEV;
47
48int	bmaj2cmaj[NUMCDEV];
49int	nblkdev = NUMCDEV;
50
51/*
52 * Routine to convert from character to block device number.
53 *
54 * A minimal stub routine can always return NODEV.
55 */
56dev_t
57chrtoblk(dev_t dev)
58{
59	struct cdevsw *cd;
60
61	if((cd = devsw(dev)) != NULL) {
62          if (cd->d_bmaj != -1)
63	    return(makedev(cd->d_bmaj,minor(dev)));
64	}
65	return(NODEV);
66}
67
68int
69cdevsw_add(dev_t *descrip,
70		struct cdevsw *newentry,
71		struct cdevsw **oldentry)
72{
73	int i ;
74
75	if ( (int)*descrip == NODEV) {	/* auto (0 is valid) */
76		/*
77		 * Search the table looking for a slot...
78		 */
79		for (i = cdevsw_ALLOCSTART; i < nchrdev; i++)
80			if (cdevsw[i] == NULL)
81				break;		/* found one! */
82		/* out of allocable slots? */
83		if (i >= nchrdev) {
84			return ENFILE;
85		}
86	} else {				/* assign */
87		i = major(*descrip);
88		if (i < 0 || i >= nchrdev) {
89			return EINVAL;
90		}
91	}
92
93	/* maybe save old */
94        if (oldentry) {
95		*oldentry = cdevsw[i];
96	}
97	if (newentry) {
98		newentry->d_bmaj = -1;
99		newentry->d_maj = i;
100	}
101	/* replace with new */
102	cdevsw[i] = newentry;
103
104	/* done!  let them know where we put it */
105	*descrip = makedev(i,0);
106	return 0;
107}
108
109/*
110 * note must call cdevsw_add before bdevsw_add due to d_bmaj hack.
111 */
112void
113cdevsw_add_generic(int bmaj, int cmaj, struct cdevsw *cdevsw)
114{
115	dev_t dev;
116
117	dev = makedev(cmaj, 0);
118	cdevsw_add(&dev, cdevsw, NULL);
119	bmaj2cmaj[bmaj] = cmaj;
120}
121
122int
123devsw_module_handler(module_t mod, int what, void* arg)
124{
125	struct devsw_module_data* data = (struct devsw_module_data*) arg;
126	int error;
127
128	switch (what) {
129	case MOD_LOAD:
130		error = cdevsw_add(&data->cdev, data->cdevsw, NULL);
131		if (!error && data->cdevsw->d_strategy != nostrategy) {
132			if (data->bdev == NODEV)
133				data->bdev = data->cdev;
134			bmaj2cmaj[major(data->bdev)] = major(data->cdev);
135		}
136		if (!error && data->chainevh)
137			error = data->chainevh(mod, what, data->chainarg);
138		return error;
139
140	case MOD_UNLOAD:
141		if (data->chainevh) {
142			error = data->chainevh(mod, what, data->chainarg);
143			if (error)
144				return error;
145		}
146		if (data->cdevsw->d_strategy != nostrategy)
147			bmaj2cmaj[major(data->bdev)] = 0;
148		error = cdevsw_add(&data->cdev, NULL, NULL);
149		return error;
150	}
151
152	if (data->chainevh)
153		return data->chainevh(mod, what, data->chainarg);
154	else
155		return 0;
156}
157