kern_conf.c revision 130640 
1/*-
2 * Copyright (c) 1999-2002 Poul-Henning Kamp
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27#include <sys/cdefs.h>
28__FBSDID("$FreeBSD: head/sys/kern/kern_conf.c 130640 2004-06-17 17:16:53Z phk $");
29
30#include <sys/param.h>
31#include <sys/kernel.h>
32#include <sys/systm.h>
33#include <sys/bio.h>
34#include <sys/lock.h>
35#include <sys/mutex.h>
36#include <sys/sysctl.h>
37#include <sys/module.h>
38#include <sys/malloc.h>
39#include <sys/conf.h>
40#include <sys/vnode.h>
41#include <sys/queue.h>
42#include <sys/poll.h>
43#include <sys/ctype.h>
44#include <sys/tty.h>
45#include <machine/stdarg.h>
46
47static MALLOC_DEFINE(M_DEVT, "struct cdev *", "struct cdev *storage");
48
49/* Built at compile time from sys/conf/majors */
50extern unsigned char reserved_majors[256];
51
52/*
53 * This is the number of hash-buckets.  Experiements with 'real-life'
54 * dev_t's show that a prime halfway between two powers of two works
55 * best.
56 */
57#define DEVT_HASH 83
58
59/* The number of struct cdev *'s we can create before malloc(9) kick in.  */
60#define DEVT_STASH 50
61
62static struct cdev devt_stash[DEVT_STASH];
63
64static LIST_HEAD(, cdev) dev_hash[DEVT_HASH];
65
66static LIST_HEAD(, cdev) dev_free;
67
68static int free_devt;
69SYSCTL_INT(_debug, OID_AUTO, free_devt, CTLFLAG_RW, &free_devt, 0, "");
70
71static struct mtx devmtx;
72static void freedev(struct cdev *dev);
73static struct cdev *newdev(int x, int y);
74
75
76static void
77devlock(void)
78{
79	if (!mtx_initialized(&devmtx))
80		mtx_init(&devmtx, "struct cdev *", NULL, MTX_DEF);
81	mtx_lock(&devmtx);
82}
83
84static void
85devunlock(void)
86{
87	mtx_unlock(&devmtx);
88}
89
90void
91dev_ref(struct cdev *dev)
92{
93	devlock();
94	dev->si_refcount++;
95	devunlock();
96}
97
98void
99dev_rel(struct cdev *dev)
100{
101	devlock();
102	dev->si_refcount--;
103	KASSERT(dev->si_refcount >= 0,
104	    ("dev_rel(%s) gave negative count", devtoname(dev)));
105	if (dev->si_devsw == NULL && dev->si_refcount == 0) {
106		LIST_REMOVE(dev, si_list);
107		freedev(dev);
108	}
109	devunlock();
110}
111
112void
113cdevsw_ref(struct cdevsw *csw)
114{
115	devlock();
116	csw->d_refcount++;
117	devunlock();
118}
119
120void
121cdevsw_rel(struct cdevsw *csw)
122{
123	devlock();
124	csw->d_refcount--;
125	KASSERT(csw->d_refcount >= 0,
126	    ("cdevsw_vrel(%s) gave negative count", csw->d_name));
127	devunlock();
128}
129
130int
131nullop(void)
132{
133
134	return (0);
135}
136
137int
138eopnotsupp(void)
139{
140
141	return (EOPNOTSUPP);
142}
143
144static int
145enxio(void)
146{
147	return (ENXIO);
148}
149
150static int
151enodev(void)
152{
153	return (ENODEV);
154}
155
156/* Define a dead_cdevsw for use when devices leave unexpectedly. */
157
158#define dead_open	(d_open_t *)enxio
159#define dead_close	(d_close_t *)enxio
160#define dead_read	(d_read_t *)enxio
161#define dead_write	(d_write_t *)enxio
162#define dead_ioctl	(d_ioctl_t *)enxio
163#define dead_poll	(d_poll_t *)enodev
164#define dead_mmap	(d_mmap_t *)enodev
165
166static void
167dead_strategy(struct bio *bp)
168{
169
170	biofinish(bp, NULL, ENXIO);
171}
172
173#define dead_dump	(dumper_t *)enxio
174#define dead_kqfilter	(d_kqfilter_t *)enxio
175
176static struct cdevsw dead_cdevsw = {
177	.d_version =	D_VERSION,
178	.d_flags =	D_NEEDGIANT, /* XXX: does dead_strategy need this ? */
179	.d_open =	dead_open,
180	.d_close =	dead_close,
181	.d_read =	dead_read,
182	.d_write =	dead_write,
183	.d_ioctl =	dead_ioctl,
184	.d_poll =	dead_poll,
185	.d_mmap =	dead_mmap,
186	.d_strategy =	dead_strategy,
187	.d_name =	"dead",
188	.d_maj =	255,
189	.d_dump =	dead_dump,
190	.d_kqfilter =	dead_kqfilter
191};
192
193/* Default methods if driver does not specify method */
194
195#define null_open	(d_open_t *)nullop
196#define null_close	(d_close_t *)nullop
197#define no_read		(d_read_t *)enodev
198#define no_write	(d_write_t *)enodev
199#define no_ioctl	(d_ioctl_t *)enodev
200#define no_mmap		(d_mmap_t *)enodev
201
202static int
203no_kqfilter(struct cdev *dev __unused, struct knote *kn __unused)
204{
205
206	return (1);
207}
208
209static void
210no_strategy(struct bio *bp)
211{
212
213	biofinish(bp, NULL, ENODEV);
214}
215
216static int
217no_poll(struct cdev *dev __unused, int events, struct thread *td __unused)
218{
219	/*
220	 * Return true for read/write.  If the user asked for something
221	 * special, return POLLNVAL, so that clients have a way of
222	 * determining reliably whether or not the extended
223	 * functionality is present without hard-coding knowledge
224	 * of specific filesystem implementations.
225	 * Stay in sync with vop_nopoll().
226	 */
227	if (events & ~POLLSTANDARD)
228		return (POLLNVAL);
229
230	return (events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM));
231}
232
233#define no_dump		(dumper_t *)enodev
234
235struct cdevsw *
236devsw(struct cdev *dev)
237{
238	if (dev->si_devsw != NULL)
239		return (dev->si_devsw);
240	return (&dead_cdevsw);
241}
242
243/*
244 * struct cdev *and u_dev_t primitives
245 */
246
247int
248major(struct cdev *x)
249{
250	if (x == NULL)
251		return NODEV;
252	return((x->si_udev >> 8) & 0xff);
253}
254
255int
256minor(struct cdev *x)
257{
258	if (x == NULL)
259		return NODEV;
260	return(x->si_udev & 0xffff00ff);
261}
262
263int
264dev2unit(struct cdev *x)
265{
266	int i;
267
268	if (x == NULL)
269		return NODEV;
270	i = minor(x);
271	return ((i & 0xff) | (i >> 8));
272}
273
274int
275unit2minor(int unit)
276{
277
278	KASSERT(unit <= 0xffffff, ("Invalid unit (%d) in unit2minor", unit));
279	return ((unit & 0xff) | ((unit << 8) & ~0xffff));
280}
281
282static struct cdev *
283allocdev(void)
284{
285	static int stashed;
286	struct cdev *si;
287
288	if (LIST_FIRST(&dev_free)) {
289		si = LIST_FIRST(&dev_free);
290		LIST_REMOVE(si, si_hash);
291	} else if (stashed >= DEVT_STASH) {
292		MALLOC(si, struct cdev *, sizeof(*si), M_DEVT,
293		    M_USE_RESERVE | M_ZERO | M_WAITOK);
294	} else {
295		si = devt_stash + stashed++;
296		bzero(si, sizeof *si);
297		si->si_flags |= SI_STASHED;
298	}
299	si->__si_namebuf[0] = '\0';
300	si->si_name = si->__si_namebuf;
301	LIST_INIT(&si->si_children);
302	TAILQ_INIT(&si->si_snapshots);
303	return (si);
304}
305
306static struct cdev *
307newdev(int x, int y)
308{
309	struct cdev *si;
310	dev_t	udev;
311	int hash;
312
313	if (x == umajor(NODEV) && y == uminor(NODEV))
314		panic("newdev of NODEV");
315	udev = (x << 8) | y;
316	hash = udev % DEVT_HASH;
317	LIST_FOREACH(si, &dev_hash[hash], si_hash) {
318		if (si->si_udev == udev)
319			return (si);
320	}
321	si = allocdev();
322	si->si_udev = udev;
323	LIST_INSERT_HEAD(&dev_hash[hash], si, si_hash);
324	return (si);
325}
326
327static void
328freedev(struct cdev *dev)
329{
330
331	if (dev->si_flags & SI_STASHED) {
332		bzero(dev, sizeof(*dev));
333		dev->si_flags |= SI_STASHED;
334		LIST_INSERT_HEAD(&dev_free, dev, si_hash);
335	} else {
336		FREE(dev, M_DEVT);
337	}
338}
339
340dev_t
341dev2udev(struct cdev *x)
342{
343	if (x == NULL)
344		return (NODEV);
345	return (x->si_udev);
346}
347
348struct cdev *
349findcdev(dev_t udev)
350{
351	struct cdev *si;
352	int hash;
353
354	if (udev == NODEV)
355		return (NULL);
356	hash = udev % DEVT_HASH;
357	LIST_FOREACH(si, &dev_hash[hash], si_hash) {
358		if (si->si_udev == udev)
359			return (si);
360	}
361	return (NULL);
362}
363
364int
365uminor(dev_t dev)
366{
367	return (dev & 0xffff00ff);
368}
369
370int
371umajor(dev_t dev)
372{
373	return ((dev & 0xff00) >> 8);
374}
375
376static void
377find_major(struct cdevsw *devsw)
378{
379	int i;
380
381	for (i = NUMCDEVSW - 1; i > 0; i--)
382		if (reserved_majors[i] != i)
383			break;
384	KASSERT(i > 0, ("Out of major numbers (%s)", devsw->d_name));
385	devsw->d_maj = i;
386	reserved_majors[i] = i;
387	devsw->d_flags |= D_ALLOCMAJ;
388}
389
390static void
391fini_cdevsw(struct cdevsw *devsw)
392{
393	if (devsw->d_flags & D_ALLOCMAJ) {
394		reserved_majors[devsw->d_maj] = 0;
395		devsw->d_maj = MAJOR_AUTO;
396		devsw->d_flags &= ~D_ALLOCMAJ;
397	} else if (devsw->d_maj == 0)
398		devsw->d_maj = 256;
399	devsw->d_flags &= ~D_INIT;
400}
401
402static void
403prep_cdevsw(struct cdevsw *devsw)
404{
405
406	devlock();
407
408	if (devsw->d_version != D_VERSION_00) {
409		printf(
410		    "WARNING: Device driver \"%s\" has wrong version %s\n",
411		    devsw->d_name, "and is disabled.  Recompile KLD module.");
412		devsw->d_open = dead_open;
413		devsw->d_close = dead_close;
414		devsw->d_read = dead_read;
415		devsw->d_write = dead_write;
416		devsw->d_ioctl = dead_ioctl;
417		devsw->d_poll = dead_poll;
418		devsw->d_mmap = dead_mmap;
419		devsw->d_strategy = dead_strategy;
420		devsw->d_dump = dead_dump;
421		devsw->d_kqfilter = dead_kqfilter;
422	}
423
424	if (devsw->d_flags & D_TTY) {
425		if (devsw->d_ioctl == NULL)	devsw->d_ioctl = ttyioctl;
426		if (devsw->d_read == NULL)	devsw->d_read = ttyread;
427		if (devsw->d_write == NULL)	devsw->d_write = ttywrite;
428		if (devsw->d_kqfilter == NULL)	devsw->d_kqfilter = ttykqfilter;
429		if (devsw->d_poll == NULL)	devsw->d_poll = ttypoll;
430	}
431
432	if (devsw->d_open == NULL)	devsw->d_open = null_open;
433	if (devsw->d_close == NULL)	devsw->d_close = null_close;
434	if (devsw->d_read == NULL)	devsw->d_read = no_read;
435	if (devsw->d_write == NULL)	devsw->d_write = no_write;
436	if (devsw->d_ioctl == NULL)	devsw->d_ioctl = no_ioctl;
437	if (devsw->d_poll == NULL)	devsw->d_poll = no_poll;
438	if (devsw->d_mmap == NULL)	devsw->d_mmap = no_mmap;
439	if (devsw->d_strategy == NULL)	devsw->d_strategy = no_strategy;
440	if (devsw->d_dump == NULL)	devsw->d_dump = no_dump;
441	if (devsw->d_kqfilter == NULL)	devsw->d_kqfilter = no_kqfilter;
442
443	LIST_INIT(&devsw->d_devs);
444
445	devsw->d_flags |= D_INIT;
446
447	if (devsw->d_maj == MAJOR_AUTO) {
448		find_major(devsw);
449	} else {
450		if (devsw->d_maj == 256)	/* XXX: tty_cons.c is magic */
451			devsw->d_maj = 0;
452		KASSERT(devsw->d_maj >= 0 && devsw->d_maj < 256,
453		    ("Invalid major (%d) in make_dev", devsw->d_maj));
454		if (reserved_majors[devsw->d_maj] != devsw->d_maj) {
455			printf("WARNING: driver \"%s\" used %s %d\n",
456			    devsw->d_name, "unreserved major device number",
457			    devsw->d_maj);
458			reserved_majors[devsw->d_maj] = devsw->d_maj;
459		}
460	}
461	devunlock();
462}
463
464struct cdev *
465make_dev(struct cdevsw *devsw, int minornr, uid_t uid, gid_t gid, int perms, const char *fmt, ...)
466{
467	struct cdev *dev;
468	va_list ap;
469	int i;
470
471	KASSERT((minornr & ~0xffff00ff) == 0,
472	    ("Invalid minor (0x%x) in make_dev", minornr));
473
474	if (!(devsw->d_flags & D_INIT))
475		prep_cdevsw(devsw);
476	dev = newdev(devsw->d_maj, minornr);
477	if (dev->si_flags & SI_CHEAPCLONE &&
478	    dev->si_flags & SI_NAMED &&
479	    dev->si_devsw == devsw) {
480		/*
481		 * This is allowed as it removes races and generally
482		 * simplifies cloning devices.
483		 * XXX: still ??
484		 */
485		return (dev);
486	}
487	devlock();
488	KASSERT(!(dev->si_flags & SI_NAMED),
489	    ("make_dev() by driver %s on pre-existing device (maj=%d, min=%d, name=%s)",
490	    devsw->d_name, major(dev), minor(dev), devtoname(dev)));
491
492	va_start(ap, fmt);
493	i = vsnrprintf(dev->__si_namebuf, sizeof dev->__si_namebuf, 32, fmt, ap);
494	if (i > (sizeof dev->__si_namebuf - 1)) {
495		printf("WARNING: Device name truncated! (%s)",
496		    dev->__si_namebuf);
497	}
498	va_end(ap);
499	dev->si_devsw = devsw;
500	dev->si_uid = uid;
501	dev->si_gid = gid;
502	dev->si_mode = perms;
503	dev->si_flags |= SI_NAMED;
504
505	LIST_INSERT_HEAD(&devsw->d_devs, dev, si_list);
506	devfs_create(dev);
507	devunlock();
508	return (dev);
509}
510
511int
512dev_named(struct cdev *pdev, const char *name)
513{
514	struct cdev *cdev;
515
516	if (strcmp(devtoname(pdev), name) == 0)
517		return (1);
518	LIST_FOREACH(cdev, &pdev->si_children, si_siblings)
519		if (strcmp(devtoname(cdev), name) == 0)
520			return (1);
521	return (0);
522}
523
524void
525dev_depends(struct cdev *pdev, struct cdev *cdev)
526{
527
528	devlock();
529	cdev->si_parent = pdev;
530	cdev->si_flags |= SI_CHILD;
531	LIST_INSERT_HEAD(&pdev->si_children, cdev, si_siblings);
532	devunlock();
533}
534
535struct cdev *
536make_dev_alias(struct cdev *pdev, const char *fmt, ...)
537{
538	struct cdev *dev;
539	va_list ap;
540	int i;
541
542	dev = allocdev();
543	devlock();
544	dev->si_flags |= SI_ALIAS;
545	dev->si_flags |= SI_NAMED;
546	va_start(ap, fmt);
547	i = vsnrprintf(dev->__si_namebuf, sizeof dev->__si_namebuf, 32, fmt, ap);
548	if (i > (sizeof dev->__si_namebuf - 1)) {
549		printf("WARNING: Device name truncated! (%s)",
550		    dev->__si_namebuf);
551	}
552	va_end(ap);
553
554	devfs_create(dev);
555	devunlock();
556	dev_depends(pdev, dev);
557	return (dev);
558}
559
560static void
561idestroy_dev(struct cdev *dev)
562{
563	if (!(dev->si_flags & SI_NAMED)) {
564		printf( "WARNING: Driver mistake: destroy_dev on %d/%d\n",
565		    major(dev), minor(dev));
566		panic("don't do that");
567	}
568
569	devfs_destroy(dev);
570
571	/* Remove name marking */
572	dev->si_flags &= ~SI_NAMED;
573
574	/* If we are a child, remove us from the parents list */
575	if (dev->si_flags & SI_CHILD) {
576		LIST_REMOVE(dev, si_siblings);
577		dev->si_flags &= ~SI_CHILD;
578	}
579
580	/* Kill our children */
581	while (!LIST_EMPTY(&dev->si_children))
582		idestroy_dev(LIST_FIRST(&dev->si_children));
583
584	/* Remove from clone list */
585	if (dev->si_flags & SI_CLONELIST) {
586		LIST_REMOVE(dev, si_clone);
587		dev->si_flags &= ~SI_CLONELIST;
588	}
589
590	if (!(dev->si_flags & SI_ALIAS)) {
591		/* Remove from cdevsw list */
592		LIST_REMOVE(dev, si_list);
593
594		/* If cdevsw has no struct cdev *'s, clean it */
595		if (LIST_EMPTY(&dev->si_devsw->d_devs))
596			fini_cdevsw(dev->si_devsw);
597
598		LIST_REMOVE(dev, si_hash);
599	}
600	dev->si_drv1 = 0;
601	dev->si_drv2 = 0;
602	dev->si_devsw = NULL;
603	bzero(&dev->__si_u, sizeof(dev->__si_u));
604	dev->si_flags &= ~SI_ALIAS;
605	if (dev->si_refcount > 0) {
606		LIST_INSERT_HEAD(&dead_cdevsw.d_devs, dev, si_list);
607	} else {
608		freedev(dev);
609	}
610}
611
612void
613destroy_dev(struct cdev *dev)
614{
615
616	devlock();
617	idestroy_dev(dev);
618	devunlock();
619}
620
621const char *
622devtoname(struct cdev *dev)
623{
624	char *p;
625	int mynor;
626
627	if (dev->si_name[0] == '#' || dev->si_name[0] == '\0') {
628		p = dev->si_name;
629		if (devsw(dev))
630			sprintf(p, "#%s/", devsw(dev)->d_name);
631		else
632			sprintf(p, "#%d/", major(dev));
633		p += strlen(p);
634		mynor = minor(dev);
635		if (mynor < 0 || mynor > 255)
636			sprintf(p, "%#x", (u_int)mynor);
637		else
638			sprintf(p, "%d", mynor);
639	}
640	return (dev->si_name);
641}
642
643int
644dev_stdclone(char *name, char **namep, const char *stem, int *unit)
645{
646	int u, i;
647
648	i = strlen(stem);
649	if (bcmp(stem, name, i) != 0)
650		return (0);
651	if (!isdigit(name[i]))
652		return (0);
653	u = 0;
654	if (name[i] == '0' && isdigit(name[i+1]))
655		return (0);
656	while (isdigit(name[i])) {
657		u *= 10;
658		u += name[i++] - '0';
659	}
660	if (u > 0xffffff)
661		return (0);
662	*unit = u;
663	if (namep)
664		*namep = &name[i];
665	if (name[i])
666		return (2);
667	return (1);
668}
669
670/*
671 * Helper functions for cloning device drivers.
672 *
673 * The objective here is to make it unnecessary for the device drivers to
674 * use rman or similar to manage their unit number space.  Due to the way
675 * we do "on-demand" devices, using rman or other "private" methods
676 * will be very tricky to lock down properly once we lock down this file.
677 *
678 * Instead we give the drivers these routines which puts the struct cdev *'s that
679 * are to be managed on their own list, and gives the driver the ability
680 * to ask for the first free unit number or a given specified unit number.
681 *
682 * In addition these routines support paired devices (pty, nmdm and similar)
683 * by respecting a number of "flag" bits in the minor number.
684 *
685 */
686
687struct clonedevs {
688	LIST_HEAD(,cdev)	head;
689};
690
691void
692clone_setup(struct clonedevs **cdp)
693{
694
695	*cdp = malloc(sizeof **cdp, M_DEVBUF, M_WAITOK | M_ZERO);
696	LIST_INIT(&(*cdp)->head);
697}
698
699int
700clone_create(struct clonedevs **cdp, struct cdevsw *csw, int *up, struct cdev **dp, u_int extra)
701{
702	struct clonedevs *cd;
703	struct cdev *dev, *dl, *de;
704	int unit, low, u;
705
706	KASSERT(*cdp != NULL,
707	    ("clone_setup() not called in driver \"%s\"", csw->d_name));
708	KASSERT(!(extra & CLONE_UNITMASK),
709	    ("Illegal extra bits (0x%x) in clone_create", extra));
710	KASSERT(*up <= CLONE_UNITMASK,
711	    ("Too high unit (0x%x) in clone_create", *up));
712
713	if (csw->d_maj == MAJOR_AUTO)
714		find_major(csw);
715
716	/*
717	 * Search the list for a lot of things in one go:
718	 *   A preexisting match is returned immediately.
719	 *   The lowest free unit number if we are passed -1, and the place
720	 *	 in the list where we should insert that new element.
721	 *   The place to insert a specified unit number, if applicable
722	 *       the end of the list.
723	 */
724	unit = *up;
725	low = extra;
726	de = dl = NULL;
727	cd = *cdp;
728	LIST_FOREACH(dev, &cd->head, si_clone) {
729		u = dev2unit(dev);
730		if (u == (unit | extra)) {
731			*dp = dev;
732			return (0);
733		}
734		if (unit == -1 && u == low) {
735			low++;
736			de = dev;
737			continue;
738		}
739		if (u > (unit | extra)) {
740			dl = dev;
741			break;
742		}
743		de = dev;
744	}
745	if (unit == -1)
746		unit = low & CLONE_UNITMASK;
747	dev = newdev(csw->d_maj, unit2minor(unit | extra));
748	KASSERT(!(dev->si_flags & SI_CLONELIST),
749	    ("Dev %p should not be on clonelist", dev));
750	if (dl != NULL)
751		LIST_INSERT_BEFORE(dl, dev, si_clone);
752	else if (de != NULL)
753		LIST_INSERT_AFTER(de, dev, si_clone);
754	else
755		LIST_INSERT_HEAD(&cd->head, dev, si_clone);
756	dev->si_flags |= SI_CLONELIST;
757	*up = unit;
758	return (1);
759}
760
761/*
762 * Kill everything still on the list.  The driver should already have
763 * disposed of any softc hung of the struct cdev *'s at this time.
764 */
765void
766clone_cleanup(struct clonedevs **cdp)
767{
768	struct cdev *dev, *tdev;
769	struct clonedevs *cd;
770
771	cd = *cdp;
772	if (cd == NULL)
773		return;
774	LIST_FOREACH_SAFE(dev, &cd->head, si_clone, tdev) {
775		KASSERT(dev->si_flags & SI_NAMED,
776		    ("Driver has goofed in cloning underways udev %x", dev->si_udev));
777		destroy_dev(dev);
778	}
779	free(cd, M_DEVBUF);
780	*cdp = NULL;
781}
782
783/*
784 * Helper sysctl for devname(3).  We're given a {u}struct cdev *and return
785 * the name, if any, registered by the device driver.
786 */
787static int
788sysctl_devname(SYSCTL_HANDLER_ARGS)
789{
790	int error;
791	dev_t ud;
792	struct cdev *dev;
793
794	error = SYSCTL_IN(req, &ud, sizeof (ud));
795	if (error)
796		return (error);
797	if (ud == NODEV)
798		return(EINVAL);
799	dev = findcdev(ud);
800	if (dev == NULL)
801		error = ENOENT;
802	else
803		error = SYSCTL_OUT(req, dev->si_name, strlen(dev->si_name) + 1);
804	return (error);
805}
806
807SYSCTL_PROC(_kern, OID_AUTO, devname, CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_ANYBODY,
808	NULL, 0, sysctl_devname, "", "devname(3) handler");
809