kern_conf.c revision 71342 
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 71342 2001-01-21 21:19:49Z 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 MALLOC_DEFINE(M_DEVT, "dev_t", "dev_t storage");
53
54/*
55 * This is the number of hash-buckets.  Experiements with 'real-life'
56 * udev_t's show that a prime halfway between two powers of two works
57 * best.
58 */
59#define DEVT_HASH 83
60
61/* The number of dev_t's we can create before malloc(9) kick in.  */
62#define DEVT_STASH 50
63
64static struct specinfo devt_stash[DEVT_STASH];
65
66static LIST_HEAD(, specinfo) dev_hash[DEVT_HASH];
67
68static LIST_HEAD(, specinfo) dev_free;
69
70devfs_create_t *devfs_create_hook;
71devfs_destroy_t *devfs_destroy_hook;
72int devfs_present;
73
74static int free_devt;
75SYSCTL_INT(_debug, OID_AUTO, free_devt, CTLFLAG_RW, &free_devt, 0, "");
76
77struct cdevsw *
78devsw(dev_t dev)
79{
80	if (dev->si_devsw)
81		return (dev->si_devsw);
82        return(cdevsw[major(dev)]);
83}
84
85/*
86 *  Add a cdevsw entry
87 */
88
89int
90cdevsw_add(struct cdevsw *newentry)
91{
92
93	if (newentry->d_maj < 0 || newentry->d_maj >= NUMCDEVSW) {
94		printf("%s: ERROR: driver has bogus cdevsw->d_maj = %d\n",
95		    newentry->d_name, newentry->d_maj);
96		return (EINVAL);
97	}
98
99	if (cdevsw[newentry->d_maj]) {
100		printf("WARNING: \"%s\" is usurping \"%s\"'s cdevsw[]\n",
101		    newentry->d_name, cdevsw[newentry->d_maj]->d_name);
102	}
103
104	cdevsw[newentry->d_maj] = newentry;
105
106	return (0);
107}
108
109/*
110 *  Remove a cdevsw entry
111 */
112
113int
114cdevsw_remove(struct cdevsw *oldentry)
115{
116	if (oldentry->d_maj < 0 || oldentry->d_maj >= NUMCDEVSW) {
117		printf("%s: ERROR: driver has bogus cdevsw->d_maj = %d\n",
118		    oldentry->d_name, oldentry->d_maj);
119		return EINVAL;
120	}
121
122	cdevsw[oldentry->d_maj] = NULL;
123
124	return 0;
125}
126
127/*
128 * dev_t and u_dev_t primitives
129 */
130
131int
132major(dev_t x)
133{
134	if (x == NODEV)
135		return NOUDEV;
136	return((x->si_udev >> 8) & 0xff);
137}
138
139int
140minor(dev_t x)
141{
142	if (x == NODEV)
143		return NOUDEV;
144	return(x->si_udev & 0xffff00ff);
145}
146
147int
148dev2unit(dev_t x)
149{
150	int i;
151
152	if (x == NODEV)
153		return NOUDEV;
154	i = minor(x);
155	return ((i & 0xff) | (i >> 8));
156}
157
158int
159unit2minor(int unit)
160{
161
162	return ((unit & 0xff) | ((unit << 8) & ~0xffff));
163}
164
165static dev_t
166allocdev(void)
167{
168	static int stashed;
169	struct specinfo *si;
170
171	if (stashed >= DEVT_STASH) {
172		MALLOC(si, struct specinfo *, sizeof(*si), M_DEVT,
173		    M_USE_RESERVE | M_ZERO);
174	} else if (LIST_FIRST(&dev_free)) {
175		si = LIST_FIRST(&dev_free);
176		LIST_REMOVE(si, si_hash);
177	} else {
178		si = devt_stash + stashed++;
179		si->si_flags |= SI_STASHED;
180	}
181	LIST_INIT(&si->si_names);
182	return (si);
183}
184
185dev_t
186makedev(int x, int y)
187{
188	struct specinfo *si;
189	udev_t	udev;
190	int hash;
191
192	if (x == umajor(NOUDEV) && y == uminor(NOUDEV))
193		panic("makedev of NOUDEV");
194	udev = (x << 8) | y;
195	hash = udev % DEVT_HASH;
196	LIST_FOREACH(si, &dev_hash[hash], si_hash) {
197		if (si->si_udev == udev)
198			return (si);
199	}
200	si = allocdev();
201	si->si_udev = udev;
202	LIST_INSERT_HEAD(&dev_hash[hash], si, si_hash);
203        return (si);
204}
205
206void
207freedev(dev_t dev)
208{
209	dev_t adev;
210
211	if (!free_devt)
212		return;
213	if (SLIST_FIRST(&dev->si_hlist))
214		return;
215	if (dev->si_devsw || dev->si_drv1 || dev->si_drv2)
216		return;
217	while (!LIST_EMPTY(&dev->si_names)) {
218		adev = LIST_FIRST(&dev->si_names);
219		adev->si_drv1 = NULL;
220		freedev(adev);
221	}
222	LIST_REMOVE(dev, si_hash);
223	if (dev->si_flags & SI_STASHED) {
224		bzero(dev, sizeof(*dev));
225		LIST_INSERT_HEAD(&dev_free, dev, si_hash);
226	} else {
227		FREE(dev, M_DEVT);
228	}
229}
230
231udev_t
232dev2udev(dev_t x)
233{
234	if (x == NODEV)
235		return NOUDEV;
236	return (x->si_udev);
237}
238
239dev_t
240udev2dev(udev_t x, int b)
241{
242
243	if (x == NOUDEV)
244		return (NODEV);
245	switch (b) {
246		case 0:
247			return makedev(umajor(x), uminor(x));
248		case 1:
249			return (NODEV);
250		default:
251			Debugger("udev2dev(...,X)");
252			return NODEV;
253	}
254}
255
256int
257uminor(udev_t dev)
258{
259	return(dev & 0xffff00ff);
260}
261
262int
263umajor(udev_t dev)
264{
265	return((dev & 0xff00) >> 8);
266}
267
268udev_t
269makeudev(int x, int y)
270{
271        return ((x << 8) | y);
272}
273
274dev_t
275make_dev(struct cdevsw *devsw, int minor, uid_t uid, gid_t gid, int perms, char *fmt, ...)
276{
277	dev_t	dev;
278	va_list ap;
279	int i;
280
281	dev = makedev(devsw->d_maj, minor);
282	if (dev->si_flags & SI_NAMED) {
283		printf( "WARNING: Driver mistake: repeat make_dev(\"%s\")\n",
284		    dev->si_name);
285		return (dev);
286	}
287	va_start(ap, fmt);
288	i = kvprintf(fmt, NULL, dev->si_name, 32, ap);
289	dev->si_name[i] = '\0';
290	va_end(ap);
291	dev->si_devsw = devsw;
292	dev->si_uid = uid;
293	dev->si_gid = gid;
294	dev->si_mode = perms;
295	dev->si_flags |= SI_NAMED;
296
297	if (devfs_create_hook)
298		devfs_create_hook(dev);
299	return (dev);
300}
301
302dev_t
303make_dev_alias(dev_t pdev, char *fmt, ...)
304{
305	dev_t	dev;
306	va_list ap;
307	int i;
308
309	dev = allocdev();
310	dev->si_flags |= SI_ALIAS;
311	dev->si_flags |= SI_NAMED;
312	dev->si_drv1 = pdev;
313	LIST_INSERT_HEAD(&pdev->si_names, dev, si_hash);
314
315	va_start(ap, fmt);
316	i = kvprintf(fmt, NULL, dev->si_name, 32, ap);
317	dev->si_name[i] = '\0';
318	va_end(ap);
319
320	if (devfs_create_hook)
321		devfs_create_hook(dev);
322	return (dev);
323}
324
325void
326destroy_dev(dev_t dev)
327{
328
329	if (!(dev->si_flags & SI_NAMED)) {
330		printf( "WARNING: Driver mistake: destroy_dev on %d/%d\n",
331		    major(dev), minor(dev));
332		return;
333	}
334
335	if (devfs_destroy_hook)
336		devfs_destroy_hook(dev);
337	dev->si_drv1 = 0;
338	dev->si_drv2 = 0;
339	dev->si_devsw = 0;
340	dev->si_flags &= ~SI_NAMED;
341	dev->si_flags &= ~SI_ALIAS;
342	freedev(dev);
343}
344
345const char *
346devtoname(dev_t dev)
347{
348	char *p;
349	int mynor;
350
351	if (dev->si_name[0] == '#' || dev->si_name[0] == '\0') {
352		p = dev->si_name;
353		if (devsw(dev))
354			sprintf(p, "#%s/", devsw(dev)->d_name);
355		else
356			sprintf(p, "#%d/", major(dev));
357		p += strlen(p);
358		mynor = minor(dev);
359		if (mynor < 0 || mynor > 255)
360			sprintf(p, "%#x", (u_int)mynor);
361		else
362			sprintf(p, "%d", mynor);
363	}
364	return (dev->si_name);
365}
366
367int
368dev_stdclone(char *name, char **namep, char *stem, int *unit)
369{
370	int u, i;
371
372	if (bcmp(stem, name, strlen(stem)) != 0)
373		return (0);
374	i = strlen(stem);
375	if (!isdigit(name[i]))
376		return (0);
377	u = 0;
378	while (isdigit(name[i])) {
379		u *= 10;
380		u += name[i++] - '0';
381	}
382	*unit = u;
383	if (namep)
384		*namep = &name[i];
385	if (name[i])
386		return (2);
387	return (1);
388}
389
390/*
391 * Helper sysctl for devname(3).  We're given a {u}dev_t and return
392 * the name, if any, registered by the device driver.
393 */
394static int
395sysctl_devname(SYSCTL_HANDLER_ARGS)
396{
397	int error;
398	udev_t ud;
399	dev_t dev;
400
401	error = SYSCTL_IN(req, &ud, sizeof (ud));
402	if (error)
403		return (error);
404	if (ud == NOUDEV)
405		return(EINVAL);
406	dev = makedev(umajor(ud), uminor(ud));
407	if (dev->si_name[0] == '\0')
408		error = ENOENT;
409	else
410		error = SYSCTL_OUT(req, dev->si_name, strlen(dev->si_name) + 1);
411	freedev(dev);
412	return (error);
413}
414
415SYSCTL_PROC(_kern, OID_AUTO, devname, CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_ANYBODY,
416	NULL, 0, sysctl_devname, "", "devname(3) handler");
417
418