kern_conf.c revision 130585 
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 130585 2004-06-16 09:47:26Z 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 * udev_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);
73
74static void
75devlock(void)
76{
77	if (!mtx_initialized(&devmtx))
78		mtx_init(&devmtx, "struct cdev *", NULL, MTX_DEF);
79	mtx_lock(&devmtx);
80}
81
82static void
83devunlock(void)
84{
85	mtx_unlock(&devmtx);
86}
87
88void
89dev_ref(struct cdev *dev)
90{
91	devlock();
92	dev->si_refcount++;
93	devunlock();
94}
95
96void
97dev_rel(struct cdev *dev)
98{
99	devlock();
100	dev->si_refcount--;
101	KASSERT(dev->si_refcount >= 0,
102	    ("dev_rel(%s) gave negative count", devtoname(dev)));
103	if (dev->si_devsw == NULL && dev->si_refcount == 0) {
104		LIST_REMOVE(dev, si_list);
105		freedev(dev);
106	}
107	devunlock();
108}
109
110void
111cdevsw_ref(struct cdevsw *csw)
112{
113	devlock();
114	csw->d_refcount++;
115	devunlock();
116}
117
118void
119cdevsw_rel(struct cdevsw *csw)
120{
121	devlock();
122	csw->d_refcount--;
123	KASSERT(csw->d_refcount >= 0,
124	    ("cdevsw_vrel(%s) gave negative count", csw->d_name));
125	devunlock();
126}
127
128static struct cdev *makedev(int x, int y);
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 == NODEV)
251		return NOUDEV;
252	return((x->si_udev >> 8) & 0xff);
253}
254
255int
256minor(struct cdev *x)
257{
258	if (x == NODEV)
259		return NOUDEV;
260	return(x->si_udev & 0xffff00ff);
261}
262
263int
264dev2unit(struct cdev *x)
265{
266	int i;
267
268	if (x == NODEV)
269		return NOUDEV;
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 *
307makedev(int x, int y)
308{
309	struct cdev *si;
310	udev_t	udev;
311	int hash;
312
313	if (x == umajor(NOUDEV) && y == uminor(NOUDEV))
314		panic("makedev of NOUDEV");
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
340udev_t
341dev2udev(struct cdev *x)
342{
343	if (x == NODEV)
344		return (NOUDEV);
345	return (x->si_udev);
346}
347
348struct cdev *
349udev2dev(udev_t udev)
350{
351	struct cdev *si;
352	int hash;
353
354	if (udev == NOUDEV)
355		return (NODEV);
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 (NODEV);
362}
363
364int
365uminor(udev_t dev)
366{
367	return (dev & 0xffff00ff);
368}
369
370int
371umajor(udev_t dev)
372{
373	return ((dev & 0xff00) >> 8);
374}
375
376udev_t
377makeudev(int x, int y)
378{
379	return ((x << 8) | y);
380}
381
382static void
383find_major(struct cdevsw *devsw)
384{
385	int i;
386
387	for (i = NUMCDEVSW - 1; i > 0; i--)
388		if (reserved_majors[i] != i)
389			break;
390	KASSERT(i > 0, ("Out of major numbers (%s)", devsw->d_name));
391	devsw->d_maj = i;
392	reserved_majors[i] = i;
393	devsw->d_flags |= D_ALLOCMAJ;
394}
395
396static void
397fini_cdevsw(struct cdevsw *devsw)
398{
399	if (devsw->d_flags & D_ALLOCMAJ) {
400		reserved_majors[devsw->d_maj] = 0;
401		devsw->d_maj = MAJOR_AUTO;
402		devsw->d_flags &= ~D_ALLOCMAJ;
403	} else if (devsw->d_maj == 0)
404		devsw->d_maj = 256;
405	devsw->d_flags &= ~D_INIT;
406}
407
408static void
409prep_cdevsw(struct cdevsw *devsw)
410{
411
412	devlock();
413
414	if (devsw->d_version != D_VERSION_00) {
415		printf(
416		    "WARNING: Device driver \"%s\" has wrong version %s\n",
417		    devsw->d_name, "and is disabled.  Recompile KLD module.");
418		devsw->d_open = dead_open;
419		devsw->d_close = dead_close;
420		devsw->d_read = dead_read;
421		devsw->d_write = dead_write;
422		devsw->d_ioctl = dead_ioctl;
423		devsw->d_poll = dead_poll;
424		devsw->d_mmap = dead_mmap;
425		devsw->d_strategy = dead_strategy;
426		devsw->d_dump = dead_dump;
427		devsw->d_kqfilter = dead_kqfilter;
428	}
429
430	if (devsw->d_flags & D_TTY) {
431		if (devsw->d_ioctl == NULL)	devsw->d_ioctl = ttyioctl;
432		if (devsw->d_read == NULL)	devsw->d_read = ttyread;
433		if (devsw->d_write == NULL)	devsw->d_write = ttywrite;
434		if (devsw->d_kqfilter == NULL)	devsw->d_kqfilter = ttykqfilter;
435		if (devsw->d_poll == NULL)	devsw->d_poll = ttypoll;
436	}
437
438	if (devsw->d_open == NULL)	devsw->d_open = null_open;
439	if (devsw->d_close == NULL)	devsw->d_close = null_close;
440	if (devsw->d_read == NULL)	devsw->d_read = no_read;
441	if (devsw->d_write == NULL)	devsw->d_write = no_write;
442	if (devsw->d_ioctl == NULL)	devsw->d_ioctl = no_ioctl;
443	if (devsw->d_poll == NULL)	devsw->d_poll = no_poll;
444	if (devsw->d_mmap == NULL)	devsw->d_mmap = no_mmap;
445	if (devsw->d_strategy == NULL)	devsw->d_strategy = no_strategy;
446	if (devsw->d_dump == NULL)	devsw->d_dump = no_dump;
447	if (devsw->d_kqfilter == NULL)	devsw->d_kqfilter = no_kqfilter;
448
449	LIST_INIT(&devsw->d_devs);
450
451	devsw->d_flags |= D_INIT;
452
453	if (devsw->d_maj == MAJOR_AUTO) {
454		find_major(devsw);
455	} else {
456		if (devsw->d_maj == 256)	/* XXX: tty_cons.c is magic */
457			devsw->d_maj = 0;
458		KASSERT(devsw->d_maj >= 0 && devsw->d_maj < 256,
459		    ("Invalid major (%d) in make_dev", devsw->d_maj));
460		if (reserved_majors[devsw->d_maj] != devsw->d_maj) {
461			printf("WARNING: driver \"%s\" used %s %d\n",
462			    devsw->d_name, "unreserved major device number",
463			    devsw->d_maj);
464			reserved_majors[devsw->d_maj] = devsw->d_maj;
465		}
466	}
467	devunlock();
468}
469
470struct cdev *
471make_dev(struct cdevsw *devsw, int minornr, uid_t uid, gid_t gid, int perms, const char *fmt, ...)
472{
473	struct cdev *dev;
474	va_list ap;
475	int i;
476
477	KASSERT((minornr & ~0xffff00ff) == 0,
478	    ("Invalid minor (0x%x) in make_dev", minornr));
479
480	if (!(devsw->d_flags & D_INIT))
481		prep_cdevsw(devsw);
482	dev = makedev(devsw->d_maj, minornr);
483	if (dev->si_flags & SI_CHEAPCLONE &&
484	    dev->si_flags & SI_NAMED &&
485	    dev->si_devsw == devsw) {
486		/*
487		 * This is allowed as it removes races and generally
488		 * simplifies cloning devices.
489		 * XXX: still ??
490		 */
491		return (dev);
492	}
493	devlock();
494	KASSERT(!(dev->si_flags & SI_NAMED),
495	    ("make_dev() by driver %s on pre-existing device (maj=%d, min=%d, name=%s)",
496	    devsw->d_name, major(dev), minor(dev), devtoname(dev)));
497
498	va_start(ap, fmt);
499	i = vsnrprintf(dev->__si_namebuf, sizeof dev->__si_namebuf, 32, fmt, ap);
500	if (i > (sizeof dev->__si_namebuf - 1)) {
501		printf("WARNING: Device name truncated! (%s)",
502		    dev->__si_namebuf);
503	}
504	va_end(ap);
505	dev->si_devsw = devsw;
506	dev->si_uid = uid;
507	dev->si_gid = gid;
508	dev->si_mode = perms;
509	dev->si_flags |= SI_NAMED;
510
511	LIST_INSERT_HEAD(&devsw->d_devs, dev, si_list);
512	devfs_create(dev);
513	devunlock();
514	return (dev);
515}
516
517int
518dev_named(struct cdev *pdev, const char *name)
519{
520	struct cdev *cdev;
521
522	if (strcmp(devtoname(pdev), name) == 0)
523		return (1);
524	LIST_FOREACH(cdev, &pdev->si_children, si_siblings)
525		if (strcmp(devtoname(cdev), name) == 0)
526			return (1);
527	return (0);
528}
529
530void
531dev_depends(struct cdev *pdev, struct cdev *cdev)
532{
533
534	devlock();
535	cdev->si_parent = pdev;
536	cdev->si_flags |= SI_CHILD;
537	LIST_INSERT_HEAD(&pdev->si_children, cdev, si_siblings);
538	devunlock();
539}
540
541struct cdev *
542make_dev_alias(struct cdev *pdev, const char *fmt, ...)
543{
544	struct cdev *dev;
545	va_list ap;
546	int i;
547
548	dev = allocdev();
549	devlock();
550	dev->si_flags |= SI_ALIAS;
551	dev->si_flags |= SI_NAMED;
552	va_start(ap, fmt);
553	i = vsnrprintf(dev->__si_namebuf, sizeof dev->__si_namebuf, 32, fmt, ap);
554	if (i > (sizeof dev->__si_namebuf - 1)) {
555		printf("WARNING: Device name truncated! (%s)",
556		    dev->__si_namebuf);
557	}
558	va_end(ap);
559
560	devfs_create(dev);
561	devunlock();
562	dev_depends(pdev, dev);
563	return (dev);
564}
565
566static void
567idestroy_dev(struct cdev *dev)
568{
569	if (!(dev->si_flags & SI_NAMED)) {
570		printf( "WARNING: Driver mistake: destroy_dev on %d/%d\n",
571		    major(dev), minor(dev));
572		panic("don't do that");
573	}
574
575	devfs_destroy(dev);
576
577	/* Remove name marking */
578	dev->si_flags &= ~SI_NAMED;
579
580	/* If we are a child, remove us from the parents list */
581	if (dev->si_flags & SI_CHILD) {
582		LIST_REMOVE(dev, si_siblings);
583		dev->si_flags &= ~SI_CHILD;
584	}
585
586	/* Kill our children */
587	while (!LIST_EMPTY(&dev->si_children))
588		idestroy_dev(LIST_FIRST(&dev->si_children));
589
590	/* Remove from clone list */
591	if (dev->si_flags & SI_CLONELIST) {
592		LIST_REMOVE(dev, si_clone);
593		dev->si_flags &= ~SI_CLONELIST;
594	}
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(&dev->si_devsw->d_devs))
602			fini_cdevsw(dev->si_devsw);
603
604		LIST_REMOVE(dev, si_hash);
605	}
606	dev->si_drv1 = 0;
607	dev->si_drv2 = 0;
608	dev->si_devsw = NULL;
609	bzero(&dev->__si_u, sizeof(dev->__si_u));
610	dev->si_flags &= ~SI_ALIAS;
611	if (dev->si_refcount > 0) {
612		LIST_INSERT_HEAD(&dead_cdevsw.d_devs, dev, si_list);
613	} else {
614		freedev(dev);
615	}
616}
617
618void
619destroy_dev(struct cdev *dev)
620{
621
622	devlock();
623	idestroy_dev(dev);
624	devunlock();
625}
626
627const char *
628devtoname(struct cdev *dev)
629{
630	char *p;
631	int mynor;
632
633	if (dev->si_name[0] == '#' || dev->si_name[0] == '\0') {
634		p = dev->si_name;
635		if (devsw(dev))
636			sprintf(p, "#%s/", devsw(dev)->d_name);
637		else
638			sprintf(p, "#%d/", major(dev));
639		p += strlen(p);
640		mynor = minor(dev);
641		if (mynor < 0 || mynor > 255)
642			sprintf(p, "%#x", (u_int)mynor);
643		else
644			sprintf(p, "%d", mynor);
645	}
646	return (dev->si_name);
647}
648
649int
650dev_stdclone(char *name, char **namep, const char *stem, int *unit)
651{
652	int u, i;
653
654	i = strlen(stem);
655	if (bcmp(stem, name, i) != 0)
656		return (0);
657	if (!isdigit(name[i]))
658		return (0);
659	u = 0;
660	if (name[i] == '0' && isdigit(name[i+1]))
661		return (0);
662	while (isdigit(name[i])) {
663		u *= 10;
664		u += name[i++] - '0';
665	}
666	if (u > 0xffffff)
667		return (0);
668	*unit = u;
669	if (namep)
670		*namep = &name[i];
671	if (name[i])
672		return (2);
673	return (1);
674}
675
676/*
677 * Helper functions for cloning device drivers.
678 *
679 * The objective here is to make it unnecessary for the device drivers to
680 * use rman or similar to manage their unit number space.  Due to the way
681 * we do "on-demand" devices, using rman or other "private" methods
682 * will be very tricky to lock down properly once we lock down this file.
683 *
684 * Instead we give the drivers these routines which puts the struct cdev *'s that
685 * are to be managed on their own list, and gives the driver the ability
686 * to ask for the first free unit number or a given specified unit number.
687 *
688 * In addition these routines support paired devices (pty, nmdm and similar)
689 * by respecting a number of "flag" bits in the minor number.
690 *
691 */
692
693struct clonedevs {
694	LIST_HEAD(,cdev)	head;
695};
696
697void
698clone_setup(struct clonedevs **cdp)
699{
700
701	*cdp = malloc(sizeof **cdp, M_DEVBUF, M_WAITOK | M_ZERO);
702	LIST_INIT(&(*cdp)->head);
703}
704
705int
706clone_create(struct clonedevs **cdp, struct cdevsw *csw, int *up, struct cdev **dp, u_int extra)
707{
708	struct clonedevs *cd;
709	struct cdev *dev, *dl, *de;
710	int unit, low, u;
711
712	KASSERT(*cdp != NULL,
713	    ("clone_setup() not called in driver \"%s\"", csw->d_name));
714	KASSERT(!(extra & CLONE_UNITMASK),
715	    ("Illegal extra bits (0x%x) in clone_create", extra));
716	KASSERT(*up <= CLONE_UNITMASK,
717	    ("Too high unit (0x%x) in clone_create", *up));
718
719	if (csw->d_maj == MAJOR_AUTO)
720		find_major(csw);
721
722	/*
723	 * Search the list for a lot of things in one go:
724	 *   A preexisting match is returned immediately.
725	 *   The lowest free unit number if we are passed -1, and the place
726	 *	 in the list where we should insert that new element.
727	 *   The place to insert a specified unit number, if applicable
728	 *       the end of the list.
729	 */
730	unit = *up;
731	low = extra;
732	de = dl = NULL;
733	cd = *cdp;
734	LIST_FOREACH(dev, &cd->head, si_clone) {
735		u = dev2unit(dev);
736		if (u == (unit | extra)) {
737			*dp = dev;
738			return (0);
739		}
740		if (unit == -1 && u == low) {
741			low++;
742			de = dev;
743			continue;
744		}
745		if (u > (unit | extra)) {
746			dl = dev;
747			break;
748		}
749		de = dev;
750	}
751	if (unit == -1)
752		unit = low & CLONE_UNITMASK;
753	dev = makedev(csw->d_maj, unit2minor(unit | extra));
754	KASSERT(!(dev->si_flags & SI_CLONELIST),
755	    ("Dev %p should not be on clonelist", dev));
756	if (dl != NULL)
757		LIST_INSERT_BEFORE(dl, dev, si_clone);
758	else if (de != NULL)
759		LIST_INSERT_AFTER(de, dev, si_clone);
760	else
761		LIST_INSERT_HEAD(&cd->head, dev, si_clone);
762	dev->si_flags |= SI_CLONELIST;
763	*up = unit;
764	return (1);
765}
766
767/*
768 * Kill everything still on the list.  The driver should already have
769 * disposed of any softc hung of the struct cdev *'s at this time.
770 */
771void
772clone_cleanup(struct clonedevs **cdp)
773{
774	struct cdev *dev, *tdev;
775	struct clonedevs *cd;
776
777	cd = *cdp;
778	if (cd == NULL)
779		return;
780	LIST_FOREACH_SAFE(dev, &cd->head, si_clone, tdev) {
781		KASSERT(dev->si_flags & SI_NAMED,
782		    ("Driver has goofed in cloning underways udev %x", dev->si_udev));
783		destroy_dev(dev);
784	}
785	free(cd, M_DEVBUF);
786	*cdp = NULL;
787}
788
789/*
790 * Helper sysctl for devname(3).  We're given a {u}struct cdev *and return
791 * the name, if any, registered by the device driver.
792 */
793static int
794sysctl_devname(SYSCTL_HANDLER_ARGS)
795{
796	int error;
797	udev_t ud;
798	struct cdev *dev;
799
800	error = SYSCTL_IN(req, &ud, sizeof (ud));
801	if (error)
802		return (error);
803	if (ud == NOUDEV)
804		return(EINVAL);
805	dev = udev2dev(ud);
806	if (dev == NODEV)
807		error = ENOENT;
808	else
809		error = SYSCTL_OUT(req, dev->si_name, strlen(dev->si_name) + 1);
810	return (error);
811}
812
813SYSCTL_PROC(_kern, OID_AUTO, devname, CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_ANYBODY,
814	NULL, 0, sysctl_devname, "", "devname(3) handler");
815