kern_conf.c revision 135844 
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 135844 2004-09-27 06:34:30Z 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, "cdev", "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.  Experiments 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
76void
77dev_lock(void)
78{
79	if (!mtx_initialized(&devmtx))
80		mtx_init(&devmtx, "cdev", NULL, MTX_DEF);
81	mtx_lock(&devmtx);
82}
83
84void
85dev_unlock(void)
86{
87
88	mtx_unlock(&devmtx);
89}
90
91void
92dev_ref(struct cdev *dev)
93{
94
95	dev_lock();
96	dev->si_refcount++;
97	dev_unlock();
98}
99
100void
101dev_rel(struct cdev *dev)
102{
103
104	dev->si_refcount--;
105	KASSERT(dev->si_refcount >= 0,
106	    ("dev_rel(%s) gave negative count", devtoname(dev)));
107	if (dev->si_devsw == NULL && dev->si_refcount == 0) {
108		LIST_REMOVE(dev, si_list);
109		freedev(dev);
110	}
111}
112struct cdevsw *
113dev_refthread(struct cdev *dev)
114{
115	struct cdevsw *csw;
116
117	mtx_assert(&devmtx, MA_NOTOWNED);
118	dev_lock();
119	csw = dev->si_devsw;
120	if (csw != NULL)
121		dev->si_threadcount++;
122	dev_unlock();
123	return (csw);
124}
125
126void
127dev_relthread(struct cdev *dev)
128{
129
130	mtx_assert(&devmtx, MA_NOTOWNED);
131	dev_lock();
132	dev->si_threadcount--;
133	dev_unlock();
134}
135
136int
137nullop(void)
138{
139
140	return (0);
141}
142
143int
144eopnotsupp(void)
145{
146
147	return (EOPNOTSUPP);
148}
149
150static int
151enxio(void)
152{
153	return (ENXIO);
154}
155
156static int
157enodev(void)
158{
159	return (ENODEV);
160}
161
162/* Define a dead_cdevsw for use when devices leave unexpectedly. */
163
164#define dead_open	(d_open_t *)enxio
165#define dead_close	(d_close_t *)enxio
166#define dead_read	(d_read_t *)enxio
167#define dead_write	(d_write_t *)enxio
168#define dead_ioctl	(d_ioctl_t *)enxio
169#define dead_poll	(d_poll_t *)enodev
170#define dead_mmap	(d_mmap_t *)enodev
171
172static void
173dead_strategy(struct bio *bp)
174{
175
176	biofinish(bp, NULL, ENXIO);
177}
178
179#define dead_dump	(dumper_t *)enxio
180#define dead_kqfilter	(d_kqfilter_t *)enxio
181
182static struct cdevsw dead_cdevsw = {
183	.d_version =	D_VERSION,
184	.d_flags =	D_NEEDGIANT, /* XXX: does dead_strategy need this ? */
185	.d_open =	dead_open,
186	.d_close =	dead_close,
187	.d_read =	dead_read,
188	.d_write =	dead_write,
189	.d_ioctl =	dead_ioctl,
190	.d_poll =	dead_poll,
191	.d_mmap =	dead_mmap,
192	.d_strategy =	dead_strategy,
193	.d_name =	"dead",
194	.d_maj =	255,
195	.d_dump =	dead_dump,
196	.d_kqfilter =	dead_kqfilter
197};
198
199/* Default methods if driver does not specify method */
200
201#define null_open	(d_open_t *)nullop
202#define null_close	(d_close_t *)nullop
203#define no_read		(d_read_t *)enodev
204#define no_write	(d_write_t *)enodev
205#define no_ioctl	(d_ioctl_t *)enodev
206#define no_mmap		(d_mmap_t *)enodev
207#define no_kqfilter	(d_kqfilter_t *)enodev
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
235/*
236 * struct cdev * and u_dev_t primitives
237 */
238
239int
240major(struct cdev *x)
241{
242	if (x == NULL)
243		return NODEV;
244	return((x->si_udev >> 8) & 0xff);
245}
246
247int
248minor(struct cdev *x)
249{
250	if (x == NULL)
251		return NODEV;
252	return(x->si_udev & 0xffff00ff);
253}
254
255int
256dev2unit(struct cdev *x)
257{
258	int i;
259
260	if (x == NULL)
261		return NODEV;
262	i = minor(x);
263	return ((i & 0xff) | (i >> 8));
264}
265
266int
267unit2minor(int unit)
268{
269
270	KASSERT(unit <= 0xffffff, ("Invalid unit (%d) in unit2minor", unit));
271	return ((unit & 0xff) | ((unit << 8) & ~0xffff));
272}
273
274static struct cdev *
275allocdev(void)
276{
277	static int stashed;
278	struct cdev *si;
279
280	if (LIST_FIRST(&dev_free)) {
281		si = LIST_FIRST(&dev_free);
282		LIST_REMOVE(si, si_hash);
283	} else if (stashed >= DEVT_STASH) {
284		MALLOC(si, struct cdev *, sizeof(*si), M_DEVT,
285		    M_USE_RESERVE | M_ZERO | M_WAITOK);
286	} else {
287		si = devt_stash + stashed++;
288		bzero(si, sizeof *si);
289		si->si_flags |= SI_STASHED;
290	}
291	si->__si_namebuf[0] = '\0';
292	si->si_name = si->__si_namebuf;
293	LIST_INIT(&si->si_children);
294	return (si);
295}
296
297static struct cdev *
298newdev(int x, int y)
299{
300	struct cdev *si;
301	dev_t	udev;
302	int hash;
303
304	if (x == umajor(NODEV) && y == uminor(NODEV))
305		panic("newdev of NODEV");
306	udev = (x << 8) | y;
307	hash = udev % DEVT_HASH;
308	LIST_FOREACH(si, &dev_hash[hash], si_hash) {
309		if (si->si_udev == udev)
310			return (si);
311	}
312	si = allocdev();
313	si->si_udev = udev;
314	LIST_INSERT_HEAD(&dev_hash[hash], si, si_hash);
315	return (si);
316}
317
318static void
319freedev(struct cdev *dev)
320{
321
322	if (dev->si_flags & SI_STASHED) {
323		bzero(dev, sizeof(*dev));
324		dev->si_flags |= SI_STASHED;
325		LIST_INSERT_HEAD(&dev_free, dev, si_hash);
326	} else {
327		FREE(dev, M_DEVT);
328	}
329}
330
331dev_t
332dev2udev(struct cdev *x)
333{
334	if (x == NULL)
335		return (NODEV);
336	return (x->si_udev);
337}
338
339struct cdev *
340findcdev(dev_t udev)
341{
342	struct cdev *si;
343	int hash;
344
345	if (udev == NODEV)
346		return (NULL);
347	hash = udev % DEVT_HASH;
348	LIST_FOREACH(si, &dev_hash[hash], si_hash) {
349		if (si->si_udev == udev)
350			return (si);
351	}
352	return (NULL);
353}
354
355int
356uminor(dev_t dev)
357{
358	return (dev & 0xffff00ff);
359}
360
361int
362umajor(dev_t dev)
363{
364	return ((dev & 0xff00) >> 8);
365}
366
367static void
368find_major(struct cdevsw *devsw)
369{
370	int i;
371
372	for (i = NUMCDEVSW - 1; i > 0; i--)
373		if (reserved_majors[i] != i)
374			break;
375	KASSERT(i > 0, ("Out of major numbers (%s)", devsw->d_name));
376	devsw->d_maj = i;
377	reserved_majors[i] = i;
378	devsw->d_flags |= D_ALLOCMAJ;
379}
380
381static void
382fini_cdevsw(struct cdevsw *devsw)
383{
384	if (devsw->d_flags & D_ALLOCMAJ) {
385		reserved_majors[devsw->d_maj] = 0;
386		devsw->d_maj = MAJOR_AUTO;
387		devsw->d_flags &= ~D_ALLOCMAJ;
388	} else if (devsw->d_maj == 0)
389		devsw->d_maj = 256;
390	devsw->d_flags &= ~D_INIT;
391}
392
393static void
394prep_cdevsw(struct cdevsw *devsw)
395{
396
397	dev_lock();
398
399	if (devsw->d_version != D_VERSION_00) {
400		printf(
401		    "WARNING: Device driver \"%s\" has wrong version %s\n",
402		    devsw->d_name, "and is disabled.  Recompile KLD module.");
403		devsw->d_open = dead_open;
404		devsw->d_close = dead_close;
405		devsw->d_read = dead_read;
406		devsw->d_write = dead_write;
407		devsw->d_ioctl = dead_ioctl;
408		devsw->d_poll = dead_poll;
409		devsw->d_mmap = dead_mmap;
410		devsw->d_strategy = dead_strategy;
411		devsw->d_dump = dead_dump;
412		devsw->d_kqfilter = dead_kqfilter;
413	}
414
415	if (devsw->d_flags & D_TTY) {
416		if (devsw->d_ioctl == NULL)	devsw->d_ioctl = ttyioctl;
417		if (devsw->d_read == NULL)	devsw->d_read = ttyread;
418		if (devsw->d_write == NULL)	devsw->d_write = ttywrite;
419		if (devsw->d_kqfilter == NULL)	devsw->d_kqfilter = ttykqfilter;
420		if (devsw->d_poll == NULL)	devsw->d_poll = ttypoll;
421	}
422
423	if (devsw->d_open == NULL)	devsw->d_open = null_open;
424	if (devsw->d_close == NULL)	devsw->d_close = null_close;
425	if (devsw->d_read == NULL)	devsw->d_read = no_read;
426	if (devsw->d_write == NULL)	devsw->d_write = no_write;
427	if (devsw->d_ioctl == NULL)	devsw->d_ioctl = no_ioctl;
428	if (devsw->d_poll == NULL)	devsw->d_poll = no_poll;
429	if (devsw->d_mmap == NULL)	devsw->d_mmap = no_mmap;
430	if (devsw->d_strategy == NULL)	devsw->d_strategy = no_strategy;
431	if (devsw->d_dump == NULL)	devsw->d_dump = no_dump;
432	if (devsw->d_kqfilter == NULL)	devsw->d_kqfilter = no_kqfilter;
433
434	LIST_INIT(&devsw->d_devs);
435
436	devsw->d_flags |= D_INIT;
437
438	if (devsw->d_maj == MAJOR_AUTO) {
439		find_major(devsw);
440	} else {
441		if (devsw->d_maj == 256)	/* XXX: tty_cons.c is magic */
442			devsw->d_maj = 0;
443		KASSERT(devsw->d_maj >= 0 && devsw->d_maj < 256,
444		    ("Invalid major (%d) in make_dev", devsw->d_maj));
445		if (reserved_majors[devsw->d_maj] != devsw->d_maj) {
446			printf("WARNING: driver \"%s\" used %s %d\n",
447			    devsw->d_name, "unreserved major device number",
448			    devsw->d_maj);
449			reserved_majors[devsw->d_maj] = devsw->d_maj;
450		}
451	}
452	dev_unlock();
453}
454
455struct cdev *
456make_dev(struct cdevsw *devsw, int minornr, uid_t uid, gid_t gid, int perms, const char *fmt, ...)
457{
458	struct cdev *dev;
459	va_list ap;
460	int i;
461
462	KASSERT((minornr & ~0xffff00ff) == 0,
463	    ("Invalid minor (0x%x) in make_dev", minornr));
464
465	if (!(devsw->d_flags & D_INIT))
466		prep_cdevsw(devsw);
467	dev = newdev(devsw->d_maj, minornr);
468	if (dev->si_flags & SI_CHEAPCLONE &&
469	    dev->si_flags & SI_NAMED &&
470	    dev->si_devsw == devsw) {
471		/*
472		 * This is allowed as it removes races and generally
473		 * simplifies cloning devices.
474		 * XXX: still ??
475		 */
476		return (dev);
477	}
478	dev_lock();
479	KASSERT(!(dev->si_flags & SI_NAMED),
480	    ("make_dev() by driver %s on pre-existing device (maj=%d, min=%d, name=%s)",
481	    devsw->d_name, major(dev), minor(dev), devtoname(dev)));
482
483	va_start(ap, fmt);
484	i = vsnrprintf(dev->__si_namebuf, sizeof dev->__si_namebuf, 32, fmt, ap);
485	if (i > (sizeof dev->__si_namebuf - 1)) {
486		printf("WARNING: Device name truncated! (%s)\n",
487		    dev->__si_namebuf);
488	}
489	va_end(ap);
490	dev->si_devsw = devsw;
491	dev->si_uid = uid;
492	dev->si_gid = gid;
493	dev->si_mode = perms;
494	dev->si_flags |= SI_NAMED;
495
496	LIST_INSERT_HEAD(&devsw->d_devs, dev, si_list);
497	devfs_create(dev);
498	dev_unlock();
499	return (dev);
500}
501
502int
503dev_named(struct cdev *pdev, const char *name)
504{
505	struct cdev *cdev;
506
507	if (strcmp(devtoname(pdev), name) == 0)
508		return (1);
509	LIST_FOREACH(cdev, &pdev->si_children, si_siblings)
510		if (strcmp(devtoname(cdev), name) == 0)
511			return (1);
512	return (0);
513}
514
515void
516dev_depends(struct cdev *pdev, struct cdev *cdev)
517{
518
519	dev_lock();
520	cdev->si_parent = pdev;
521	cdev->si_flags |= SI_CHILD;
522	LIST_INSERT_HEAD(&pdev->si_children, cdev, si_siblings);
523	dev_unlock();
524}
525
526struct cdev *
527make_dev_alias(struct cdev *pdev, const char *fmt, ...)
528{
529	struct cdev *dev;
530	va_list ap;
531	int i;
532
533	dev = allocdev();
534	dev_lock();
535	dev->si_flags |= SI_ALIAS;
536	dev->si_flags |= SI_NAMED;
537	va_start(ap, fmt);
538	i = vsnrprintf(dev->__si_namebuf, sizeof dev->__si_namebuf, 32, fmt, ap);
539	if (i > (sizeof dev->__si_namebuf - 1)) {
540		printf("WARNING: Device name truncated! (%s)\n",
541		    dev->__si_namebuf);
542	}
543	va_end(ap);
544
545	devfs_create(dev);
546	dev_unlock();
547	dev_depends(pdev, dev);
548	return (dev);
549}
550
551static void
552idestroy_dev(struct cdev *dev)
553{
554	struct cdevsw *csw;
555
556	KASSERT(dev->si_flags & SI_NAMED,
557	    ("WARNING: Driver mistake: destroy_dev on %d/%d\n",
558	    major(dev), minor(dev)));
559
560	devfs_destroy(dev);
561
562	/* Remove name marking */
563	dev->si_flags &= ~SI_NAMED;
564
565	/* If we are a child, remove us from the parents list */
566	if (dev->si_flags & SI_CHILD) {
567		LIST_REMOVE(dev, si_siblings);
568		dev->si_flags &= ~SI_CHILD;
569	}
570
571	/* Kill our children */
572	while (!LIST_EMPTY(&dev->si_children))
573		idestroy_dev(LIST_FIRST(&dev->si_children));
574
575	/* Remove from clone list */
576	if (dev->si_flags & SI_CLONELIST) {
577		LIST_REMOVE(dev, si_clone);
578		dev->si_flags &= ~SI_CLONELIST;
579	}
580
581	csw = dev->si_devsw;
582	dev->si_devsw = NULL;
583	while (csw->d_purge != NULL && dev->si_threadcount) {
584		printf("Purging %lu threads from %s\n",
585		    dev->si_threadcount, devtoname(dev));
586		csw->d_purge(dev);
587		msleep(csw, &devmtx, PRIBIO, "devprg", hz/10);
588	}
589	if (csw->d_purge != NULL)
590		printf("All threads purged from %s\n", devtoname(dev));
591
592	dev->si_drv1 = 0;
593	dev->si_drv2 = 0;
594	bzero(&dev->__si_u, sizeof(dev->__si_u));
595
596	if (!(dev->si_flags & SI_ALIAS)) {
597		/* Remove from cdevsw list */
598		LIST_REMOVE(dev, si_list);
599
600		/* If cdevsw has no struct cdev *'s, clean it */
601		if (LIST_EMPTY(&csw->d_devs))
602			fini_cdevsw(csw);
603
604		LIST_REMOVE(dev, si_hash);
605	}
606	dev->si_flags &= ~SI_ALIAS;
607
608	if (dev->si_refcount > 0) {
609		LIST_INSERT_HEAD(&dead_cdevsw.d_devs, dev, si_list);
610	} else {
611		freedev(dev);
612	}
613}
614
615void
616destroy_dev(struct cdev *dev)
617{
618
619	dev_lock();
620	idestroy_dev(dev);
621	dev_unlock();
622}
623
624const char *
625devtoname(struct cdev *dev)
626{
627	char *p;
628	struct cdevsw *csw;
629	int mynor;
630
631	if (dev->si_name[0] == '#' || dev->si_name[0] == '\0') {
632		p = dev->si_name;
633		sprintf(p, "#%d", major(dev));
634		p += strlen(p);
635		csw = dev_refthread(dev);
636		if (csw != NULL) {
637			sprintf(p, "(%s)", csw->d_name);
638			dev_relthread(dev);
639		}
640		p += strlen(p);
641		mynor = minor(dev);
642		if (mynor < 0 || mynor > 255)
643			sprintf(p, "/%#x", (u_int)mynor);
644		else
645			sprintf(p, "/%d", mynor);
646	}
647	return (dev->si_name);
648}
649
650int
651dev_stdclone(char *name, char **namep, const char *stem, int *unit)
652{
653	int u, i;
654
655	i = strlen(stem);
656	if (bcmp(stem, name, i) != 0)
657		return (0);
658	if (!isdigit(name[i]))
659		return (0);
660	u = 0;
661	if (name[i] == '0' && isdigit(name[i+1]))
662		return (0);
663	while (isdigit(name[i])) {
664		u *= 10;
665		u += name[i++] - '0';
666	}
667	if (u > 0xffffff)
668		return (0);
669	*unit = u;
670	if (namep)
671		*namep = &name[i];
672	if (name[i])
673		return (2);
674	return (1);
675}
676
677/*
678 * Helper functions for cloning device drivers.
679 *
680 * The objective here is to make it unnecessary for the device drivers to
681 * use rman or similar to manage their unit number space.  Due to the way
682 * we do "on-demand" devices, using rman or other "private" methods
683 * will be very tricky to lock down properly once we lock down this file.
684 *
685 * Instead we give the drivers these routines which puts the struct cdev *'s
686 * that are to be managed on their own list, and gives the driver the ability
687 * to ask for the first free unit number or a given specified unit number.
688 *
689 * In addition these routines support paired devices (pty, nmdm and similar)
690 * by respecting a number of "flag" bits in the minor number.
691 *
692 */
693
694struct clonedevs {
695	LIST_HEAD(,cdev)	head;
696};
697
698void
699clone_setup(struct clonedevs **cdp)
700{
701
702	*cdp = malloc(sizeof **cdp, M_DEVBUF, M_WAITOK | M_ZERO);
703	LIST_INIT(&(*cdp)->head);
704}
705
706int
707clone_create(struct clonedevs **cdp, struct cdevsw *csw, int *up, struct cdev **dp, u_int extra)
708{
709	struct clonedevs *cd;
710	struct cdev *dev, *dl, *de;
711	int unit, low, u;
712
713	KASSERT(*cdp != NULL,
714	    ("clone_setup() not called in driver \"%s\"", csw->d_name));
715	KASSERT(!(extra & CLONE_UNITMASK),
716	    ("Illegal extra bits (0x%x) in clone_create", extra));
717	KASSERT(*up <= CLONE_UNITMASK,
718	    ("Too high unit (0x%x) in clone_create", *up));
719
720	if (csw->d_maj == MAJOR_AUTO)
721		find_major(csw);
722
723	/*
724	 * Search the list for a lot of things in one go:
725	 *   A preexisting match is returned immediately.
726	 *   The lowest free unit number if we are passed -1, and the place
727	 *	 in the list where we should insert that new element.
728	 *   The place to insert a specified unit number, if applicable
729	 *       the end of the list.
730	 */
731	unit = *up;
732	low = extra;
733	de = dl = NULL;
734	cd = *cdp;
735	LIST_FOREACH(dev, &cd->head, si_clone) {
736		u = dev2unit(dev);
737		if (u == (unit | extra)) {
738			*dp = dev;
739			return (0);
740		}
741		if (unit == -1 && u == low) {
742			low++;
743			de = dev;
744			continue;
745		}
746		if (u > (unit | extra)) {
747			dl = dev;
748			break;
749		}
750		de = dev;
751	}
752	if (unit == -1)
753		unit = low & CLONE_UNITMASK;
754	dev = newdev(csw->d_maj, unit2minor(unit | extra));
755	KASSERT(!(dev->si_flags & SI_CLONELIST),
756	    ("Dev %p should not be on clonelist", dev));
757	if (dl != NULL)
758		LIST_INSERT_BEFORE(dl, dev, si_clone);
759	else if (de != NULL)
760		LIST_INSERT_AFTER(de, dev, si_clone);
761	else
762		LIST_INSERT_HEAD(&cd->head, dev, si_clone);
763	dev->si_flags |= SI_CLONELIST;
764	*up = unit;
765	return (1);
766}
767
768/*
769 * Kill everything still on the list.  The driver should already have
770 * disposed of any softc hung of the struct cdev *'s at this time.
771 */
772void
773clone_cleanup(struct clonedevs **cdp)
774{
775	struct cdev *dev, *tdev;
776	struct clonedevs *cd;
777
778	cd = *cdp;
779	if (cd == NULL)
780		return;
781	LIST_FOREACH_SAFE(dev, &cd->head, si_clone, tdev) {
782		KASSERT(dev->si_flags & SI_NAMED,
783		    ("Driver has goofed in cloning underways udev %x", dev->si_udev));
784		destroy_dev(dev);
785	}
786	free(cd, M_DEVBUF);
787	*cdp = NULL;
788}
789
790/*
791 * Helper sysctl for devname(3).  We're given a struct cdev * and return
792 * the name, if any, registered by the device driver.
793 */
794static int
795sysctl_devname(SYSCTL_HANDLER_ARGS)
796{
797	int error;
798	dev_t ud;
799	struct cdev *dev;
800
801	error = SYSCTL_IN(req, &ud, sizeof (ud));
802	if (error)
803		return (error);
804	if (ud == NODEV)
805		return(EINVAL);
806	dev = findcdev(ud);
807	if (dev == NULL)
808		error = ENOENT;
809	else
810		error = SYSCTL_OUT(req, dev->si_name, strlen(dev->si_name) + 1);
811	return (error);
812}
813
814SYSCTL_PROC(_kern, OID_AUTO, devname, CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_ANYBODY,
815	NULL, 0, sysctl_devname, "", "devname(3) handler");
816