kern_conf.c revision 40648 
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 1.27 1998/07/04 22:30:21 julian 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 cdevsw *cd;
61
62	if(cd = cdevsw[major(dev)]) {
63          if (cd->d_bmaj != -1)
64	    return(makedev(cd->d_bmaj,minor(dev)));
65	}
66	return(NODEV);
67}
68
69/*
70 * (re)place an entry in the bdevsw or cdevsw table
71 * return the slot used in major(*descrip)
72 */
73static int
74bdevsw_add(dev_t *descrip,
75		struct cdevsw *newentry,
76		struct cdevsw **oldentry)
77{
78	int i ;
79
80	if ( (int)*descrip == NODEV) {	/* auto (0 is valid) */
81		/*
82		 * Search the table looking for a slot...
83		 */
84		for (i = bdevsw_ALLOCSTART; i < nblkdev; i++)
85			if (bdevsw[i] == NULL)
86				break;		/* found one! */
87		/* out of allocable slots? */
88		if (i >= nblkdev) {
89			return ENFILE;
90		}
91	} else {				/* assign */
92		i = major(*descrip);
93		if (i < 0 || i >= nblkdev) {
94			return EINVAL;
95		}
96	}
97
98	/* maybe save old */
99        if (oldentry) {
100		*oldentry = bdevsw[i];
101	}
102	if (newentry) {
103		newentry->d_bmaj = i;
104	}
105	/* replace with new */
106	bdevsw[i] = newentry;
107
108	/* done!  let them know where we put it */
109	*descrip = makedev(i,0);
110	return 0;
111}
112
113int
114cdevsw_add(dev_t *descrip,
115		struct cdevsw *newentry,
116		struct cdevsw **oldentry)
117{
118	int i ;
119
120	if ( (int)*descrip == NODEV) {	/* auto (0 is valid) */
121		/*
122		 * Search the table looking for a slot...
123		 */
124		for (i = cdevsw_ALLOCSTART; i < nchrdev; i++)
125			if (cdevsw[i] == NULL)
126				break;		/* found one! */
127		/* out of allocable slots? */
128		if (i >= nchrdev) {
129			return ENFILE;
130		}
131	} else {				/* assign */
132		i = major(*descrip);
133		if (i < 0 || i >= nchrdev) {
134			return EINVAL;
135		}
136	}
137
138	/* maybe save old */
139        if (oldentry) {
140		*oldentry = cdevsw[i];
141	}
142	if (newentry) {
143		newentry->d_bmaj = -1;
144		newentry->d_maj = i;
145	}
146	/* replace with new */
147	cdevsw[i] = newentry;
148
149	/* done!  let them know where we put it */
150	*descrip = makedev(i,0);
151	return 0;
152}
153
154/*
155 * note must call cdevsw_add before bdevsw_add due to d_bmaj hack.
156 */
157void
158cdevsw_add_generic(int bdev, int cdev, struct cdevsw *cdevsw)
159{
160	dev_t dev;
161
162	dev = makedev(cdev, 0);
163	cdevsw_add(&dev, cdevsw, NULL);
164	dev = makedev(bdev, 0);
165	bdevsw_add(&dev, cdevsw, NULL);
166}
167
168int
169cdevsw_module_handler(module_t mod, modeventtype_t what, void* arg)
170{
171	struct cdevsw_module_data* data = (struct cdevsw_module_data*) arg;
172	int error;
173
174	switch (what) {
175	case MOD_LOAD:
176		if (error = cdevsw_add(&data->dev, data->cdevsw, NULL))
177			return error;
178		break;
179
180	case MOD_UNLOAD:
181		if (error = cdevsw_add(&data->dev, NULL, NULL))
182			return error;
183		break;
184	}
185
186	if (data->chainevh)
187		return data->chainevh(mod, what, data->chainarg);
188	else
189		return 0;
190}
191
192int
193bdevsw_module_handler(module_t mod, modeventtype_t what, void* arg)
194{
195	struct bdevsw_module_data* data = (struct bdevsw_module_data*) arg;
196	int error;
197
198	switch (what) {
199	case MOD_LOAD:
200		if (error = cdevsw_add(&data->cdev, data->cdevsw, NULL))
201			return error;
202		if (error = bdevsw_add(&data->bdev, data->cdevsw, NULL)) {
203			cdevsw_add(&data->bdev, NULL, NULL);
204			return error;
205		}
206		break;
207
208	case MOD_UNLOAD:
209		if (error = bdevsw_add(&data->bdev, NULL, NULL))
210			return error;
211		if (error = cdevsw_add(&data->cdev, NULL, NULL))
212			return error;
213		break;
214	}
215
216	if (data->chainevh)
217		return data->chainevh(mod, what, data->chainarg);
218	else
219		return 0;
220}
221