kern_conf.c revision 65747 
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 * $FreeBSD: head/sys/kern/kern_conf.c 65747 2000-09-11 17:15:33Z phk $
34 */
35
36#include <sys/param.h>
37#include <sys/kernel.h>
38#include <sys/sysctl.h>
39#include <sys/systm.h>
40#include <sys/module.h>
41#include <sys/malloc.h>
42#include <sys/conf.h>
43#include <sys/vnode.h>
44#include <sys/queue.h>
45#include <sys/ctype.h>
46#include <machine/stdarg.h>
47
48#define cdevsw_ALLOCSTART	(NUMCDEVSW/2)
49
50struct cdevsw 	*cdevsw[NUMCDEVSW];
51
52static int	bmaj2cmaj[NUMCDEVSW];
53
54MALLOC_DEFINE(M_DEVT, "dev_t", "dev_t storage");
55
56/*
57 * This is the number of hash-buckets.  Experiements with 'real-life'
58 * udev_t's show that a prime halfway between two powers of two works
59 * best.
60 */
61#define DEVT_HASH 83
62
63/* The number of dev_t's we can create before malloc(9) kick in.  */
64#define DEVT_STASH 50
65
66static struct specinfo devt_stash[DEVT_STASH];
67
68static LIST_HEAD(, specinfo) dev_hash[DEVT_HASH];
69
70static LIST_HEAD(, specinfo) dev_free;
71
72devfs_create_t *devfs_create_hook;
73devfs_destroy_t *devfs_destroy_hook;
74int devfs_present;
75
76static int free_devt;
77SYSCTL_INT(_debug, OID_AUTO, free_devt, CTLFLAG_RW, &free_devt, 0, "");
78
79struct cdevsw *
80devsw(dev_t dev)
81{
82	if (dev->si_devsw)
83		return (dev->si_devsw);
84        return(cdevsw[major(dev)]);
85}
86
87/*
88 *  Add a cdevsw entry
89 */
90
91int
92cdevsw_add(struct cdevsw *newentry)
93{
94	int i;
95	static int setup;
96
97	if (!setup) {
98		for (i = 0; i < NUMCDEVSW; i++)
99			if (!bmaj2cmaj[i])
100				bmaj2cmaj[i] = 254;
101		setup++;
102	}
103
104	if (newentry->d_maj < 0 || newentry->d_maj >= NUMCDEVSW) {
105		printf("%s: ERROR: driver has bogus cdevsw->d_maj = %d\n",
106		    newentry->d_name, newentry->d_maj);
107		return (EINVAL);
108	}
109	if (newentry->d_bmaj >= NUMCDEVSW) {
110		printf("%s: ERROR: driver has bogus cdevsw->d_bmaj = %d\n",
111		    newentry->d_name, newentry->d_bmaj);
112		return (EINVAL);
113	}
114	if (newentry->d_bmaj >= 0 && (newentry->d_flags & D_DISK) == 0) {
115		printf("ERROR: \"%s\" bmaj but is not a disk\n",
116		    newentry->d_name);
117		return (EINVAL);
118	}
119
120	if (cdevsw[newentry->d_maj]) {
121		printf("WARNING: \"%s\" is usurping \"%s\"'s cdevsw[]\n",
122		    newentry->d_name, cdevsw[newentry->d_maj]->d_name);
123	}
124
125	cdevsw[newentry->d_maj] = newentry;
126
127	if (newentry->d_bmaj < 0)
128		return (0);
129
130	if (bmaj2cmaj[newentry->d_bmaj] != 254) {
131		printf("WARNING: \"%s\" is usurping \"%s\"'s bmaj\n",
132		    newentry->d_name,
133		    cdevsw[bmaj2cmaj[newentry->d_bmaj]]->d_name);
134	}
135	bmaj2cmaj[newentry->d_bmaj] = newentry->d_maj;
136	return (0);
137}
138
139/*
140 *  Remove a cdevsw entry
141 */
142
143int
144cdevsw_remove(struct cdevsw *oldentry)
145{
146	if (oldentry->d_maj < 0 || oldentry->d_maj >= NUMCDEVSW) {
147		printf("%s: ERROR: driver has bogus cdevsw->d_maj = %d\n",
148		    oldentry->d_name, oldentry->d_maj);
149		return EINVAL;
150	}
151
152	cdevsw[oldentry->d_maj] = NULL;
153
154	if (oldentry->d_bmaj >= 0 && oldentry->d_bmaj < NUMCDEVSW)
155		bmaj2cmaj[oldentry->d_bmaj] = 254;
156
157	return 0;
158}
159
160/*
161 * dev_t and u_dev_t primitives
162 */
163
164int
165major(dev_t x)
166{
167	if (x == NODEV)
168		return NOUDEV;
169	return((x->si_udev >> 8) & 0xff);
170}
171
172int
173minor(dev_t x)
174{
175	if (x == NODEV)
176		return NOUDEV;
177	return(x->si_udev & 0xffff00ff);
178}
179
180int
181lminor(dev_t x)
182{
183	int i;
184
185	if (x == NODEV)
186		return NOUDEV;
187	i = minor(x);
188	return ((i & 0xff) | (i >> 8));
189}
190
191dev_t
192makebdev(int x, int y)
193{
194
195	if (x == umajor(NOUDEV) && y == uminor(NOUDEV))
196		Debugger("makebdev of NOUDEV");
197	return (makedev(bmaj2cmaj[x], y));
198}
199
200static dev_t
201allocdev(void)
202{
203	static int stashed;
204	struct specinfo *si;
205
206	if (stashed >= DEVT_STASH) {
207		MALLOC(si, struct specinfo *, sizeof(*si), M_DEVT,
208		    M_USE_RESERVE);
209		bzero(si, sizeof(*si));
210	} else if (LIST_FIRST(&dev_free)) {
211		si = LIST_FIRST(&dev_free);
212		LIST_REMOVE(si, si_hash);
213	} else {
214		si = devt_stash + stashed++;
215		si->si_flags |= SI_STASHED;
216	}
217	LIST_INIT(&si->si_names);
218	return (si);
219}
220
221dev_t
222makedev(int x, int y)
223{
224	struct specinfo *si;
225	udev_t	udev;
226	int hash;
227
228	if (x == umajor(NOUDEV) && y == uminor(NOUDEV))
229		Debugger("makedev of NOUDEV");
230	udev = (x << 8) | y;
231	hash = udev % DEVT_HASH;
232	LIST_FOREACH(si, &dev_hash[hash], si_hash) {
233		if (si->si_udev == udev)
234			return (si);
235	}
236	si = allocdev();
237	si->si_udev = udev;
238	LIST_INSERT_HEAD(&dev_hash[hash], si, si_hash);
239        return (si);
240}
241
242void
243freedev(dev_t dev)
244{
245	dev_t adev;
246
247	if (!free_devt)
248		return;
249	if (SLIST_FIRST(&dev->si_hlist))
250		return;
251	if (dev->si_devsw || dev->si_drv1 || dev->si_drv2)
252		return;
253	while (!LIST_EMPTY(&dev->si_names)) {
254		adev = LIST_FIRST(&dev->si_names);
255		adev->si_drv1 = NULL;
256		freedev(adev);
257	}
258	LIST_REMOVE(dev, si_hash);
259	if (dev->si_flags & SI_STASHED) {
260		bzero(dev, sizeof(*dev));
261		LIST_INSERT_HEAD(&dev_free, dev, si_hash);
262	} else {
263		FREE(dev, M_DEVT);
264	}
265}
266
267udev_t
268dev2udev(dev_t x)
269{
270	if (x == NODEV)
271		return NOUDEV;
272	return (x->si_udev);
273}
274
275dev_t
276udev2dev(udev_t x, int b)
277{
278
279	if (x == NOUDEV)
280		return (NODEV);
281	switch (b) {
282		case 0:
283			return makedev(umajor(x), uminor(x));
284		case 1:
285			return makebdev(umajor(x), uminor(x));
286		default:
287			Debugger("udev2dev(...,X)");
288			return NODEV;
289	}
290}
291
292int
293uminor(udev_t dev)
294{
295	return(dev & 0xffff00ff);
296}
297
298int
299umajor(udev_t dev)
300{
301	return((dev & 0xff00) >> 8);
302}
303
304udev_t
305makeudev(int x, int y)
306{
307        return ((x << 8) | y);
308}
309
310dev_t
311make_dev(struct cdevsw *devsw, int minor, uid_t uid, gid_t gid, int perms, char *fmt, ...)
312{
313	dev_t	dev;
314	va_list ap;
315	int i;
316
317	dev = makedev(devsw->d_maj, minor);
318	if (dev->si_flags & SI_NAMED) {
319		printf( "WARNING: Driver mistake: repeat make_dev(\"%s\")\n",
320		    dev->si_name);
321		return (dev);
322	}
323	va_start(ap, fmt);
324	i = kvprintf(fmt, NULL, dev->si_name, 32, ap);
325	dev->si_name[i] = '\0';
326	va_end(ap);
327	dev->si_devsw = devsw;
328	dev->si_uid = uid;
329	dev->si_gid = gid;
330	dev->si_mode = perms;
331	dev->si_flags |= SI_NAMED;
332
333	if (devfs_create_hook)
334		devfs_create_hook(dev);
335	return (dev);
336}
337
338dev_t
339make_dev_alias(dev_t pdev, char *fmt, ...)
340{
341	dev_t	dev;
342	va_list ap;
343	int i;
344
345	dev = allocdev();
346	dev->si_flags |= SI_ALIAS;
347	dev->si_flags |= SI_NAMED;
348	dev->si_drv1 = pdev;
349	LIST_INSERT_HEAD(&pdev->si_names, dev, si_hash);
350
351	va_start(ap, fmt);
352	i = kvprintf(fmt, NULL, dev->si_name, 32, ap);
353	dev->si_name[i] = '\0';
354	va_end(ap);
355
356	if (devfs_create_hook)
357		devfs_create_hook(dev);
358	return (dev);
359}
360
361void
362destroy_dev(dev_t dev)
363{
364
365	if (!(dev->si_flags & SI_NAMED)) {
366		printf( "WARNING: Driver mistake: destroy_dev on %d/%d\n",
367		    major(dev), minor(dev));
368		return;
369	}
370
371	if (devfs_destroy_hook)
372		devfs_destroy_hook(dev);
373	dev->si_drv1 = 0;
374	dev->si_drv2 = 0;
375	dev->si_devsw = 0;
376	dev->si_flags &= ~SI_NAMED;
377	dev->si_flags &= ~SI_ALIAS;
378	freedev(dev);
379}
380
381const char *
382devtoname(dev_t dev)
383{
384	char *p;
385	int mynor;
386
387	if (dev->si_name[0] == '#' || dev->si_name[0] == '\0') {
388		p = dev->si_name;
389		if (devsw(dev))
390			sprintf(p, "#%s/", devsw(dev)->d_name);
391		else
392			sprintf(p, "#%d/", major(dev));
393		p += strlen(p);
394		mynor = minor(dev);
395		if (mynor < 0 || mynor > 255)
396			sprintf(p, "%#x", (u_int)mynor);
397		else
398			sprintf(p, "%d", mynor);
399	}
400	return (dev->si_name);
401}
402
403int
404dev_stdclone(char *name, char **namep, char *stem, int *unit)
405{
406	int u, i;
407
408	if (bcmp(stem, name, strlen(stem)) != 0)
409		return (0);
410	i = strlen(stem);
411	if (!isdigit(name[i]))
412		return (0);
413	u = 0;
414	while (isdigit(name[i])) {
415		u *= 10;
416		u += name[i++] - '0';
417	}
418	*unit = u;
419	if (namep)
420		*namep = &name[i];
421	if (name[i])
422		return (2);
423	return (1);
424}
425
426/*
427 * Helper sysctl for devname(3).  We're given a {u}dev_t and return
428 * the name, if any, registered by the device driver.
429 */
430static int
431sysctl_devname(SYSCTL_HANDLER_ARGS)
432{
433	int error;
434	udev_t ud;
435	dev_t dev;
436
437	error = SYSCTL_IN(req, &ud, sizeof (ud));
438	if (error)
439		return (error);
440	dev = makedev(umajor(ud), uminor(ud));
441	if (dev->si_name[0] == '\0')
442		error = ENOENT;
443	else
444		error = SYSCTL_OUT(req, dev->si_name, strlen(dev->si_name) + 1);
445	freedev(dev);
446	return (error);
447}
448
449SYSCTL_PROC(_kern, OID_AUTO, devname, CTLTYPE_OPAQUE|CTLFLAG_RW,
450	NULL, 0, sysctl_devname, "", "devname(3) handler");
451
452