kern_conf.c revision 37389 
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 1.26 1998/06/26 18:14:25 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 NUMBDEV 128
43#define NUMCDEV 256
44#define bdevsw_ALLOCSTART	(NUMBDEV/2)
45#define cdevsw_ALLOCSTART	(NUMCDEV/2)
46
47struct cdevsw 	*bdevsw[NUMBDEV];
48int	nblkdev = NUMBDEV;
49struct cdevsw 	*cdevsw[NUMCDEV];
50int	nchrdev = NUMCDEV;
51
52/*
53 * Routine to convert from character to block device number.
54 *
55 * A minimal stub routine can always return NODEV.
56 */
57dev_t
58chrtoblk(dev_t dev)
59{
60	struct bdevsw *bd;
61	struct cdevsw *cd;
62
63	if(cd = cdevsw[major(dev)]) {
64          if (cd->d_bmaj != -1)
65	    return(makedev(cd->d_bmaj,minor(dev)));
66	}
67	return(NODEV);
68}
69
70/*
71 * (re)place an entry in the bdevsw or cdevsw table
72 * return the slot used in major(*descrip)
73 */
74static int
75bdevsw_add(dev_t *descrip,
76		struct cdevsw *newentry,
77		struct cdevsw **oldentry)
78{
79	int i ;
80
81	if ( (int)*descrip == NODEV) {	/* auto (0 is valid) */
82		/*
83		 * Search the table looking for a slot...
84		 */
85		for (i = bdevsw_ALLOCSTART; i < nblkdev; i++)
86			if (bdevsw[i] == NULL)
87				break;		/* found one! */
88		/* out of allocable slots? */
89		if (i >= nblkdev) {
90			return ENFILE;
91		}
92	} else {				/* assign */
93		i = major(*descrip);
94		if (i < 0 || i >= nblkdev) {
95			return EINVAL;
96		}
97	}
98
99	/* maybe save old */
100        if (oldentry) {
101		*oldentry = bdevsw[i];
102	}
103	if (newentry) {
104		newentry->d_bmaj = i;
105	}
106	/* replace with new */
107	bdevsw[i] = newentry;
108
109	/* done!  let them know where we put it */
110	*descrip = makedev(i,0);
111	return 0;
112}
113
114int
115cdevsw_add(dev_t *descrip,
116		struct cdevsw *newentry,
117		struct cdevsw **oldentry)
118{
119	int i ;
120
121	if ( (int)*descrip == NODEV) {	/* auto (0 is valid) */
122		/*
123		 * Search the table looking for a slot...
124		 */
125		for (i = cdevsw_ALLOCSTART; i < nchrdev; i++)
126			if (cdevsw[i] == NULL)
127				break;		/* found one! */
128		/* out of allocable slots? */
129		if (i >= nchrdev) {
130			return ENFILE;
131		}
132	} else {				/* assign */
133		i = major(*descrip);
134		if (i < 0 || i >= nchrdev) {
135			return EINVAL;
136		}
137	}
138
139	/* maybe save old */
140        if (oldentry) {
141		*oldentry = cdevsw[i];
142	}
143	if (newentry) {
144		newentry->d_bmaj = -1;
145		newentry->d_maj = i;
146	}
147	/* replace with new */
148	cdevsw[i] = newentry;
149
150	/* done!  let them know where we put it */
151	*descrip = makedev(i,0);
152	return 0;
153}
154
155/*
156 * note must call cdevsw_add before bdevsw_add due to d_bmaj hack.
157 */
158void
159cdevsw_add_generic(int bdev, int cdev, struct cdevsw *cdevsw)
160{
161	dev_t dev;
162
163	dev = makedev(cdev, 0);
164	cdevsw_add(&dev, cdevsw, NULL);
165	dev = makedev(bdev, 0);
166	bdevsw_add(&dev, cdevsw, NULL);
167}
168
169int
170cdevsw_module_handler(module_t mod, modeventtype_t what, void* arg)
171{
172	struct cdevsw_module_data* data = (struct cdevsw_module_data*) arg;
173	int error;
174
175	switch (what) {
176	case MOD_LOAD:
177		if (error = cdevsw_add(&data->dev, data->cdevsw, NULL))
178			return error;
179		break;
180
181	case MOD_UNLOAD:
182		if (error = cdevsw_add(&data->dev, NULL, NULL))
183			return error;
184		break;
185	}
186
187	if (data->chainevh)
188		return data->chainevh(mod, what, data->chainarg);
189	else
190		return 0;
191}
192
193int
194bdevsw_module_handler(module_t mod, modeventtype_t what, void* arg)
195{
196	struct bdevsw_module_data* data = (struct bdevsw_module_data*) arg;
197	int error;
198
199	switch (what) {
200	case MOD_LOAD:
201		if (error = cdevsw_add(&data->cdev, data->cdevsw, NULL))
202			return error;
203		if (error = bdevsw_add(&data->bdev, data->cdevsw, NULL)) {
204			cdevsw_add(&data->bdev, NULL, NULL);
205			return error;
206		}
207		break;
208
209	case MOD_UNLOAD:
210		if (error = bdevsw_add(&data->bdev, NULL, NULL))
211			return error;
212		if (error = cdevsw_add(&data->cdev, NULL, NULL))
213			return error;
214		break;
215	}
216
217	if (data->chainevh)
218		return data->chainevh(mod, what, data->chainarg);
219	else
220		return 0;
221}
222