kern_conf.c revision 95446 
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 95446 2002-04-25 13:17:33Z bde $
34 */
35
36#include <sys/param.h>
37#include <sys/kernel.h>
38#include <sys/systm.h>
39#include <sys/lock.h>
40#include <sys/mutex.h>
41#include <sys/sysctl.h>
42#include <sys/module.h>
43#include <sys/malloc.h>
44#include <sys/conf.h>
45#include <sys/vnode.h>
46#include <sys/queue.h>
47#include <sys/ctype.h>
48#include <machine/stdarg.h>
49
50#define cdevsw_ALLOCSTART	(NUMCDEVSW/2)
51
52static struct cdevsw 	*cdevsw[NUMCDEVSW];
53
54static MALLOC_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 ready_for_devs;
77
78static int free_devt;
79SYSCTL_INT(_debug, OID_AUTO, free_devt, CTLFLAG_RW, &free_devt, 0, "");
80
81/* XXX: This is a hack */
82void disk_dev_synth(dev_t dev);
83
84struct cdevsw *
85devsw(dev_t dev)
86{
87	if (dev->si_devsw)
88		return (dev->si_devsw);
89	/* XXX: Hack around our backwards disk code */
90	disk_dev_synth(dev);
91	if (dev->si_devsw)
92		return (dev->si_devsw);
93	if (devfs_present)
94		return (NULL);
95        return(cdevsw[major(dev)]);
96}
97
98/*
99 *  Add a cdevsw entry
100 */
101
102int
103cdevsw_add(struct cdevsw *newentry)
104{
105
106	if (newentry->d_maj < 0 || newentry->d_maj >= NUMCDEVSW) {
107		printf("%s: ERROR: driver has bogus cdevsw->d_maj = %d\n",
108		    newentry->d_name, newentry->d_maj);
109		return (EINVAL);
110	}
111
112	if (cdevsw[newentry->d_maj]) {
113		printf("WARNING: \"%s\" is usurping \"%s\"'s cdevsw[]\n",
114		    newentry->d_name, cdevsw[newentry->d_maj]->d_name);
115	}
116
117	cdevsw[newentry->d_maj] = newentry;
118
119	return (0);
120}
121
122/*
123 *  Remove a cdevsw entry
124 */
125
126int
127cdevsw_remove(struct cdevsw *oldentry)
128{
129	if (oldentry->d_maj < 0 || oldentry->d_maj >= NUMCDEVSW) {
130		printf("%s: ERROR: driver has bogus cdevsw->d_maj = %d\n",
131		    oldentry->d_name, oldentry->d_maj);
132		return EINVAL;
133	}
134
135	cdevsw[oldentry->d_maj] = NULL;
136
137	return 0;
138}
139
140/*
141 * dev_t and u_dev_t primitives
142 */
143
144int
145major(dev_t x)
146{
147	if (x == NODEV)
148		return NOUDEV;
149	return((x->si_udev >> 8) & 0xff);
150}
151
152int
153minor(dev_t x)
154{
155	if (x == NODEV)
156		return NOUDEV;
157	return(x->si_udev & 0xffff00ff);
158}
159
160int
161dev2unit(dev_t x)
162{
163	int i;
164
165	if (x == NODEV)
166		return NOUDEV;
167	i = minor(x);
168	return ((i & 0xff) | (i >> 8));
169}
170
171int
172unit2minor(int unit)
173{
174
175	KASSERT(unit <= 0xffffff, ("Invalid unit (%d) in unit2minor", unit));
176	return ((unit & 0xff) | ((unit << 8) & ~0xffff));
177}
178
179static dev_t
180allocdev(void)
181{
182	static int stashed;
183	struct specinfo *si;
184
185	if (stashed >= DEVT_STASH) {
186		MALLOC(si, struct specinfo *, sizeof(*si), M_DEVT,
187		    M_USE_RESERVE | M_ZERO);
188	} else if (LIST_FIRST(&dev_free)) {
189		si = LIST_FIRST(&dev_free);
190		LIST_REMOVE(si, si_hash);
191	} else {
192		si = devt_stash + stashed++;
193		bzero(si, sizeof *si);
194	si->si_flags |= SI_STASHED;
195	}
196	LIST_INIT(&si->si_children);
197	TAILQ_INIT(&si->si_snapshots);
198	return (si);
199}
200
201dev_t
202makedev(int x, int y)
203{
204	struct specinfo *si;
205	udev_t	udev;
206	int hash;
207
208	if (x == umajor(NOUDEV) && y == uminor(NOUDEV))
209		panic("makedev of NOUDEV");
210	udev = (x << 8) | y;
211	hash = udev % DEVT_HASH;
212	LIST_FOREACH(si, &dev_hash[hash], si_hash) {
213		if (si->si_udev == udev)
214			return (si);
215	}
216	si = allocdev();
217	si->si_udev = udev;
218	LIST_INSERT_HEAD(&dev_hash[hash], si, si_hash);
219        return (si);
220}
221
222void
223freedev(dev_t dev)
224{
225
226	if (!free_devt)
227		return;
228	if (SLIST_FIRST(&dev->si_hlist))
229		return;
230	if (dev->si_devsw || dev->si_drv1 || dev->si_drv2)
231		return;
232	LIST_REMOVE(dev, si_hash);
233	if (dev->si_flags & SI_STASHED) {
234		bzero(dev, sizeof(*dev));
235		dev->si_flags |= SI_STASHED;
236		LIST_INSERT_HEAD(&dev_free, dev, si_hash);
237	} else {
238		FREE(dev, M_DEVT);
239	}
240}
241
242udev_t
243dev2udev(dev_t x)
244{
245	if (x == NODEV)
246		return NOUDEV;
247	return (x->si_udev);
248}
249
250dev_t
251udev2dev(udev_t x, int b)
252{
253
254	if (x == NOUDEV)
255		return (NODEV);
256	switch (b) {
257		case 0:
258			return makedev(umajor(x), uminor(x));
259		case 1:
260			return (NODEV);
261		default:
262			Debugger("udev2dev(...,X)");
263			return NODEV;
264	}
265}
266
267int
268uminor(udev_t dev)
269{
270	return(dev & 0xffff00ff);
271}
272
273int
274umajor(udev_t dev)
275{
276	return((dev & 0xff00) >> 8);
277}
278
279udev_t
280makeudev(int x, int y)
281{
282        return ((x << 8) | y);
283}
284
285dev_t
286make_dev(struct cdevsw *devsw, int minor, uid_t uid, gid_t gid, int perms, const char *fmt, ...)
287{
288	dev_t	dev;
289	va_list ap;
290	int i;
291
292	KASSERT(umajor(makeudev(devsw->d_maj, minor)) == devsw->d_maj,
293	    ("Invalid minor (%d) in make_dev", minor));
294
295	if (!ready_for_devs) {
296		printf("WARNING: Driver mistake: make_dev(%s) called before SI_SUB_DRIVERS\n",
297		       fmt);
298		/* XXX panic here once drivers are cleaned up */
299	}
300
301	dev = makedev(devsw->d_maj, minor);
302	if (dev->si_flags & SI_NAMED) {
303		printf( "WARNING: Driver mistake: repeat make_dev(\"%s\")\n",
304		    dev->si_name);
305		panic("don't do that");
306		return (dev);
307	}
308	va_start(ap, fmt);
309	i = kvprintf(fmt, NULL, dev->si_name, 32, ap);
310	dev->si_name[i] = '\0';
311	va_end(ap);
312	dev->si_devsw = devsw;
313	dev->si_uid = uid;
314	dev->si_gid = gid;
315	dev->si_mode = perms;
316	dev->si_flags |= SI_NAMED;
317
318	if (devfs_create_hook)
319		devfs_create_hook(dev);
320	return (dev);
321}
322
323int
324dev_named(dev_t pdev, const char *name)
325{
326	dev_t cdev;
327
328	if (strcmp(devtoname(pdev), name) == 0)
329		return (1);
330	LIST_FOREACH(cdev, &pdev->si_children, si_siblings)
331		if (strcmp(devtoname(cdev), name) == 0)
332			return (1);
333	return (0);
334}
335
336void
337dev_depends(dev_t pdev, dev_t cdev)
338{
339
340	cdev->si_parent = pdev;
341	cdev->si_flags |= SI_CHILD;
342	LIST_INSERT_HEAD(&pdev->si_children, cdev, si_siblings);
343}
344
345dev_t
346make_dev_alias(dev_t pdev, const char *fmt, ...)
347{
348	dev_t	dev;
349	va_list ap;
350	int i;
351
352	dev = allocdev();
353	dev->si_flags |= SI_ALIAS;
354	dev->si_flags |= SI_NAMED;
355	dev_depends(pdev, dev);
356	va_start(ap, fmt);
357	i = kvprintf(fmt, NULL, dev->si_name, 32, ap);
358	dev->si_name[i] = '\0';
359	va_end(ap);
360
361	if (devfs_create_hook)
362		devfs_create_hook(dev);
363	return (dev);
364}
365
366void
367revoke_and_destroy_dev(dev_t dev)
368{
369	struct vnode *vp;
370
371	GIANT_REQUIRED;
372
373	vp = SLIST_FIRST(&dev->si_hlist);
374	if (vp != NULL)
375		VOP_REVOKE(vp, REVOKEALL);
376	destroy_dev(dev);
377}
378
379void
380destroy_dev(dev_t dev)
381{
382
383	if (!(dev->si_flags & SI_NAMED)) {
384		printf( "WARNING: Driver mistake: destroy_dev on %d/%d\n",
385		    major(dev), minor(dev));
386		panic("don't do that");
387		return;
388	}
389
390	if (devfs_destroy_hook)
391		devfs_destroy_hook(dev);
392	if (dev->si_flags & SI_CHILD) {
393		LIST_REMOVE(dev, si_siblings);
394		dev->si_flags &= ~SI_CHILD;
395	}
396	while (!LIST_EMPTY(&dev->si_children))
397		destroy_dev(LIST_FIRST(&dev->si_children));
398	dev->si_drv1 = 0;
399	dev->si_drv2 = 0;
400	dev->si_devsw = 0;
401	bzero(&dev->__si_u, sizeof(dev->__si_u));
402	dev->si_flags &= ~SI_NAMED;
403	dev->si_flags &= ~SI_ALIAS;
404	freedev(dev);
405}
406
407const char *
408devtoname(dev_t dev)
409{
410	char *p;
411	int mynor;
412
413	if (dev->si_name[0] == '#' || dev->si_name[0] == '\0') {
414		p = dev->si_name;
415		if (devsw(dev))
416			sprintf(p, "#%s/", devsw(dev)->d_name);
417		else
418			sprintf(p, "#%d/", major(dev));
419		p += strlen(p);
420		mynor = minor(dev);
421		if (mynor < 0 || mynor > 255)
422			sprintf(p, "%#x", (u_int)mynor);
423		else
424			sprintf(p, "%d", mynor);
425	}
426	return (dev->si_name);
427}
428
429int
430dev_stdclone(char *name, char **namep, const char *stem, int *unit)
431{
432	int u, i;
433
434	i = strlen(stem);
435	if (bcmp(stem, name, i) != 0)
436		return (0);
437	if (!isdigit(name[i]))
438		return (0);
439	u = 0;
440	if (name[i] == '0' && isdigit(name[i+1]))
441		return (0);
442	while (isdigit(name[i])) {
443		u *= 10;
444		u += name[i++] - '0';
445	}
446	*unit = u;
447	if (namep)
448		*namep = &name[i];
449	if (name[i])
450		return (2);
451	return (1);
452}
453
454/*
455 * Helper sysctl for devname(3).  We're given a {u}dev_t and return
456 * the name, if any, registered by the device driver.
457 */
458static int
459sysctl_devname(SYSCTL_HANDLER_ARGS)
460{
461	int error;
462	udev_t ud;
463	dev_t dev;
464
465	error = SYSCTL_IN(req, &ud, sizeof (ud));
466	if (error)
467		return (error);
468	if (ud == NOUDEV)
469		return(EINVAL);
470	dev = makedev(umajor(ud), uminor(ud));
471	if (dev->si_name[0] == '\0')
472		error = ENOENT;
473	else
474		error = SYSCTL_OUT(req, dev->si_name, strlen(dev->si_name) + 1);
475	freedev(dev);
476	return (error);
477}
478
479SYSCTL_PROC(_kern, OID_AUTO, devname, CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_ANYBODY,
480	NULL, 0, sysctl_devname, "", "devname(3) handler");
481
482/*
483 * Set ready_for_devs; prior to this point, device creation is not allowed.
484 */
485static void
486dev_set_ready(void *junk)
487{
488	ready_for_devs = 1;
489}
490
491SYSINIT(dev_ready, SI_SUB_DEVFS, SI_ORDER_FIRST, dev_set_ready, NULL);
492