xref: /netbsd-src/sys/kern/kern_subr.c (revision aad9773e38ed2370a628a6416e098f9008fc10a7)
1 /*	$NetBSD: kern_subr.c,v 1.216 2014/11/22 11:04:57 mlelstv Exp $	*/
2 
3 /*-
4  * Copyright (c) 1997, 1998, 1999, 2002, 2007, 2008 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
9  * NASA Ames Research Center, and by Luke Mewburn.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
21  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
22  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
23  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
24  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
25  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
26  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
27  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
28  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
29  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
30  * POSSIBILITY OF SUCH DAMAGE.
31  */
32 
33 /*
34  * Copyright (c) 1982, 1986, 1991, 1993
35  *	The Regents of the University of California.  All rights reserved.
36  * (c) UNIX System Laboratories, Inc.
37  * All or some portions of this file are derived from material licensed
38  * to the University of California by American Telephone and Telegraph
39  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
40  * the permission of UNIX System Laboratories, Inc.
41  *
42  * Copyright (c) 1992, 1993
43  *	The Regents of the University of California.  All rights reserved.
44  *
45  * This software was developed by the Computer Systems Engineering group
46  * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
47  * contributed to Berkeley.
48  *
49  * All advertising materials mentioning features or use of this software
50  * must display the following acknowledgement:
51  *	This product includes software developed by the University of
52  *	California, Lawrence Berkeley Laboratory.
53  *
54  * Redistribution and use in source and binary forms, with or without
55  * modification, are permitted provided that the following conditions
56  * are met:
57  * 1. Redistributions of source code must retain the above copyright
58  *    notice, this list of conditions and the following disclaimer.
59  * 2. Redistributions in binary form must reproduce the above copyright
60  *    notice, this list of conditions and the following disclaimer in the
61  *    documentation and/or other materials provided with the distribution.
62  * 3. Neither the name of the University nor the names of its contributors
63  *    may be used to endorse or promote products derived from this software
64  *    without specific prior written permission.
65  *
66  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
67  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
68  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
69  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
70  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
71  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
72  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
73  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
74  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
75  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
76  * SUCH DAMAGE.
77  *
78  *	@(#)kern_subr.c	8.4 (Berkeley) 2/14/95
79  */
80 
81 #include <sys/cdefs.h>
82 __KERNEL_RCSID(0, "$NetBSD: kern_subr.c,v 1.216 2014/11/22 11:04:57 mlelstv Exp $");
83 
84 #include "opt_ddb.h"
85 #include "opt_md.h"
86 #include "opt_tftproot.h"
87 
88 #include <sys/param.h>
89 #include <sys/systm.h>
90 #include <sys/proc.h>
91 #include <sys/mount.h>
92 #include <sys/device.h>
93 #include <sys/reboot.h>
94 #include <sys/conf.h>
95 #include <sys/disk.h>
96 #include <sys/disklabel.h>
97 #include <sys/queue.h>
98 #include <sys/fcntl.h>
99 #include <sys/kauth.h>
100 #include <sys/stat.h>
101 #include <sys/vnode.h>
102 #include <sys/module.h>
103 
104 #include <dev/cons.h>
105 
106 #include <net/if.h>
107 
108 /* XXX these should eventually move to subr_autoconf.c */
109 static device_t finddevice(const char *);
110 static device_t getdisk(char *, int, int, dev_t *, int);
111 static device_t parsedisk(char *, int, int, dev_t *);
112 static const char *getwedgename(const char *, int);
113 
114 #ifdef TFTPROOT
115 int tftproot_dhcpboot(device_t);
116 #endif
117 
118 dev_t	dumpcdev;	/* for savecore */
119 
120 static int
121 isswap(device_t dv)
122 {
123 	struct dkwedge_info wi;
124 	struct vnode *vn;
125 	int error;
126 
127 	if (device_class(dv) != DV_DISK || !device_is_a(dv, "dk"))
128 		return 0;
129 
130 	if ((vn = opendisk(dv)) == NULL)
131 		return 0;
132 
133 	error = VOP_IOCTL(vn, DIOCGWEDGEINFO, &wi, FREAD, NOCRED);
134 	VOP_CLOSE(vn, FREAD, NOCRED);
135 	vput(vn);
136 	if (error) {
137 #ifdef DEBUG_WEDGE
138 		printf("%s: Get wedge info returned %d\n", device_xname(dv), error);
139 #endif
140 		return 0;
141 	}
142 	return strcmp(wi.dkw_ptype, DKW_PTYPE_SWAP) == 0;
143 }
144 
145 /*
146  * Determine the root device and, if instructed to, the root file system.
147  */
148 
149 #ifdef MEMORY_DISK_IS_ROOT
150 int md_is_root = 1;
151 #else
152 int md_is_root = 0;
153 #endif
154 
155 /*
156  * The device and partition that we booted from.
157  */
158 device_t booted_device;
159 int booted_partition;
160 daddr_t booted_startblk;
161 uint64_t booted_nblks;
162 char *bootspec;
163 
164 /*
165  * Use partition letters if it's a disk class but not a wedge.
166  * XXX Check for wedge is kinda gross.
167  */
168 #define	DEV_USES_PARTITIONS(dv)						\
169 	(device_class((dv)) == DV_DISK &&				\
170 	 !device_is_a((dv), "dk"))
171 
172 void
173 setroot(device_t bootdv, int bootpartition)
174 {
175 	device_t dv;
176 	deviter_t di;
177 	int len, majdev;
178 	dev_t nrootdev;
179 	dev_t ndumpdev = NODEV;
180 	char buf[128];
181 	const char *rootdevname;
182 	const char *dumpdevname;
183 	device_t rootdv = NULL;		/* XXX gcc -Wuninitialized */
184 	device_t dumpdv = NULL;
185 	struct ifnet *ifp;
186 	const char *deffsname;
187 	struct vfsops *vops;
188 
189 #ifdef TFTPROOT
190 	if (tftproot_dhcpboot(bootdv) != 0)
191 		boothowto |= RB_ASKNAME;
192 #endif
193 
194 	/*
195 	 * For root on md0 we have to force the attachment of md0.
196 	 */
197 	if (md_is_root) {
198 		int md_major;
199 		dev_t md_dev;
200 
201 		bootdv = NULL;
202 		md_major = devsw_name2blk("md", NULL, 0);
203 		if (md_major >= 0) {
204 			md_dev = MAKEDISKDEV(md_major, 0, RAW_PART);
205 			if (bdev_open(md_dev, FREAD, S_IFBLK, curlwp) == 0)
206 				bootdv = device_find_by_xname("md0");
207 		}
208 		if (bootdv == NULL)
209 			panic("Cannot open \"md0\" (root)");
210 	}
211 
212 	/*
213 	 * Let bootcode augment "rootspec".
214 	 */
215 	if (rootspec == NULL)
216 		rootspec = bootspec;
217 
218 	/*
219 	 * If NFS is specified as the file system, and we found
220 	 * a DV_DISK boot device (or no boot device at all), then
221 	 * find a reasonable network interface for "rootspec".
222 	 */
223 	vops = vfs_getopsbyname(MOUNT_NFS);
224 	if (vops != NULL && strcmp(rootfstype, MOUNT_NFS) == 0 &&
225 	    rootspec == NULL &&
226 	    (bootdv == NULL || device_class(bootdv) != DV_IFNET)) {
227 		IFNET_FOREACH(ifp) {
228 			if ((ifp->if_flags &
229 			     (IFF_LOOPBACK|IFF_POINTOPOINT)) == 0)
230 				break;
231 		}
232 		if (ifp == NULL) {
233 			/*
234 			 * Can't find a suitable interface; ask the
235 			 * user.
236 			 */
237 			boothowto |= RB_ASKNAME;
238 		} else {
239 			/*
240 			 * Have a suitable interface; behave as if
241 			 * the user specified this interface.
242 			 */
243 			rootspec = (const char *)ifp->if_xname;
244 		}
245 	}
246 	if (vops != NULL)
247 		vfs_delref(vops);
248 
249 	/*
250 	 * If wildcarded root and we the boot device wasn't determined,
251 	 * ask the user.
252 	 */
253 	if (rootspec == NULL && bootdv == NULL)
254 		boothowto |= RB_ASKNAME;
255 
256  top:
257 	if (boothowto & RB_ASKNAME) {
258 		device_t defdumpdv;
259 
260 		for (;;) {
261 			printf("root device");
262 			if (bootdv != NULL) {
263 				printf(" (default %s", device_xname(bootdv));
264 				if (DEV_USES_PARTITIONS(bootdv))
265 					printf("%c", bootpartition + 'a');
266 				printf(")");
267 			}
268 			printf(": ");
269 			len = cngetsn(buf, sizeof(buf));
270 			if (len == 0 && bootdv != NULL) {
271 				strlcpy(buf, device_xname(bootdv), sizeof(buf));
272 				len = strlen(buf);
273 			}
274 			if (len > 0 && buf[len - 1] == '*') {
275 				buf[--len] = '\0';
276 				dv = getdisk(buf, len, 1, &nrootdev, 0);
277 				if (dv != NULL) {
278 					rootdv = dv;
279 					break;
280 				}
281 			}
282 			dv = getdisk(buf, len, bootpartition, &nrootdev, 0);
283 			if (dv != NULL) {
284 				rootdv = dv;
285 				break;
286 			}
287 		}
288 
289 		/*
290 		 * Set up the default dump device.  If root is on
291 		 * a network device, there is no default dump
292 		 * device, since we don't support dumps to the
293 		 * network.
294 		 */
295 		if (DEV_USES_PARTITIONS(rootdv) == 0)
296 			defdumpdv = NULL;
297 		else
298 			defdumpdv = rootdv;
299 
300 		for (;;) {
301 			printf("dump device");
302 			if (defdumpdv != NULL) {
303 				/*
304 				 * Note, we know it's a disk if we get here.
305 				 */
306 				printf(" (default %sb)", device_xname(defdumpdv));
307 			}
308 			printf(": ");
309 			len = cngetsn(buf, sizeof(buf));
310 			if (len == 0) {
311 				if (defdumpdv != NULL) {
312 					ndumpdev = MAKEDISKDEV(major(nrootdev),
313 					    DISKUNIT(nrootdev), 1);
314 				}
315 				dumpdv = defdumpdv;
316 				break;
317 			}
318 			if (len == 4 && strcmp(buf, "none") == 0) {
319 				dumpdv = NULL;
320 				break;
321 			}
322 			dv = getdisk(buf, len, 1, &ndumpdev, 1);
323 			if (dv != NULL) {
324 				dumpdv = dv;
325 				break;
326 			}
327 		}
328 
329 		rootdev = nrootdev;
330 		dumpdev = ndumpdev;
331 
332 		for (vops = LIST_FIRST(&vfs_list); vops != NULL;
333 		     vops = LIST_NEXT(vops, vfs_list)) {
334 			if (vops->vfs_mountroot != NULL &&
335 			    strcmp(rootfstype, vops->vfs_name) == 0)
336 			break;
337 		}
338 
339 		if (vops == NULL) {
340 			deffsname = "generic";
341 		} else
342 			deffsname = vops->vfs_name;
343 
344 		for (;;) {
345 			printf("file system (default %s): ", deffsname);
346 			len = cngetsn(buf, sizeof(buf));
347 			if (len == 0) {
348 				if (strcmp(deffsname, "generic") == 0)
349 					rootfstype = ROOT_FSTYPE_ANY;
350 				break;
351 			}
352 			if (len == 4 && strcmp(buf, "halt") == 0)
353 				cpu_reboot(RB_HALT, NULL);
354 			else if (len == 6 && strcmp(buf, "reboot") == 0)
355 				cpu_reboot(0, NULL);
356 #if defined(DDB)
357 			else if (len == 3 && strcmp(buf, "ddb") == 0) {
358 				console_debugger();
359 			}
360 #endif
361 			else if (len == 7 && strcmp(buf, "generic") == 0) {
362 				rootfstype = ROOT_FSTYPE_ANY;
363 				break;
364 			}
365 			vops = vfs_getopsbyname(buf);
366 			if (vops == NULL || vops->vfs_mountroot == NULL) {
367 				printf("use one of: generic");
368 				for (vops = LIST_FIRST(&vfs_list);
369 				     vops != NULL;
370 				     vops = LIST_NEXT(vops, vfs_list)) {
371 					if (vops->vfs_mountroot != NULL)
372 						printf(" %s", vops->vfs_name);
373 				}
374 				if (vops != NULL)
375 					vfs_delref(vops);
376 #if defined(DDB)
377 				printf(" ddb");
378 #endif
379 				printf(" halt reboot\n");
380 			} else {
381 				/*
382 				 * XXX If *vops gets freed between here and
383 				 * the call to mountroot(), rootfstype will
384 				 * point to something unexpected.  But in
385 				 * this case the system will fail anyway.
386 				 */
387 				rootfstype = vops->vfs_name;
388 				vfs_delref(vops);
389 				break;
390 			}
391 		}
392 
393 	} else if (rootspec == NULL) {
394 		/*
395 		 * Wildcarded root; use the boot device.
396 		 */
397 		rootdv = bootdv;
398 
399 		if (bootdv)
400 			majdev = devsw_name2blk(device_xname(bootdv), NULL, 0);
401 		else
402 			majdev = -1;
403 		if (majdev >= 0) {
404 			/*
405 			 * Root is on a disk.  `bootpartition' is root,
406 			 * unless the device does not use partitions.
407 			 */
408 			if (DEV_USES_PARTITIONS(bootdv))
409 				rootdev = MAKEDISKDEV(majdev,
410 						      device_unit(bootdv),
411 						      bootpartition);
412 			else
413 				rootdev = makedev(majdev, device_unit(bootdv));
414 		}
415 	} else {
416 
417 		/*
418 		 * `root on <dev> ...'
419 		 */
420 
421 		/*
422 		 * If it's a network interface, we can bail out
423 		 * early.
424 		 */
425 		dv = finddevice(rootspec);
426 		if (dv != NULL && device_class(dv) == DV_IFNET) {
427 			rootdv = dv;
428 			goto haveroot;
429 		}
430 
431 		if (rootdev == NODEV &&
432 		    dv != NULL && device_class(dv) == DV_DISK &&
433 		    device_is_a(dv, "dk") &&
434 		    (majdev = devsw_name2blk(device_xname(dv), NULL, 0)) >= 0)
435 			rootdev = makedev(majdev, device_unit(dv));
436 
437 		rootdevname = devsw_blk2name(major(rootdev));
438 		if (rootdevname == NULL) {
439 			printf("unknown device major 0x%llx\n",
440 			    (unsigned long long)rootdev);
441 			boothowto |= RB_ASKNAME;
442 			goto top;
443 		}
444 		memset(buf, 0, sizeof(buf));
445 		snprintf(buf, sizeof(buf), "%s%llu", rootdevname,
446 		    (unsigned long long)DISKUNIT(rootdev));
447 
448 		rootdv = finddevice(buf);
449 		if (rootdv == NULL) {
450 			printf("device %s (0x%llx) not configured\n",
451 			    buf, (unsigned long long)rootdev);
452 			boothowto |= RB_ASKNAME;
453 			goto top;
454 		}
455 	}
456 
457  haveroot:
458 
459 	root_device = rootdv;
460 
461 	switch (device_class(rootdv)) {
462 	case DV_IFNET:
463 	case DV_DISK:
464 		aprint_normal("root on %s", device_xname(rootdv));
465 		if (DEV_USES_PARTITIONS(rootdv))
466 			aprint_normal("%c", (int)DISKPART(rootdev) + 'a');
467 		break;
468 
469 	default:
470 		printf("can't determine root device\n");
471 		boothowto |= RB_ASKNAME;
472 		goto top;
473 	}
474 
475 	/*
476 	 * Now configure the dump device.
477 	 *
478 	 * If we haven't figured out the dump device, do so, with
479 	 * the following rules:
480 	 *
481 	 *	(a) We already know dumpdv in the RB_ASKNAME case.
482 	 *
483 	 *	(b) If dumpspec is set, try to use it.  If the device
484 	 *	    is not available, punt.
485 	 *
486 	 *	(c) If dumpspec is not set, the dump device is
487 	 *	    wildcarded or unspecified.  If the root device
488 	 *	    is DV_IFNET, punt.  Otherwise, use partition b
489 	 *	    of the root device.
490 	 */
491 
492 	if (boothowto & RB_ASKNAME) {		/* (a) */
493 		if (dumpdv == NULL)
494 			goto nodumpdev;
495 	} else if (dumpspec != NULL) {		/* (b) */
496 		if (strcmp(dumpspec, "none") == 0 || dumpdev == NODEV) {
497 			/*
498 			 * Operator doesn't want a dump device.
499 			 * Or looks like they tried to pick a network
500 			 * device.  Oops.
501 			 */
502 			goto nodumpdev;
503 		}
504 
505 		dumpdevname = devsw_blk2name(major(dumpdev));
506 		if (dumpdevname == NULL)
507 			goto nodumpdev;
508 		memset(buf, 0, sizeof(buf));
509 		snprintf(buf, sizeof(buf), "%s%llu", dumpdevname,
510 		    (unsigned long long)DISKUNIT(dumpdev));
511 
512 		dumpdv = finddevice(buf);
513 		if (dumpdv == NULL) {
514 			/*
515 			 * Device not configured.
516 			 */
517 			goto nodumpdev;
518 		}
519 	} else {				/* (c) */
520 		if (DEV_USES_PARTITIONS(rootdv) == 0) {
521 			for (dv = deviter_first(&di, DEVITER_F_ROOT_FIRST);
522 			     dv != NULL;
523 			     dv = deviter_next(&di))
524 				if (isswap(dv))
525 					break;
526 			deviter_release(&di);
527 			if (dv == NULL)
528 				goto nodumpdev;
529 
530 			majdev = devsw_name2blk(device_xname(dv), NULL, 0);
531 			if (majdev < 0)
532 				goto nodumpdev;
533 			dumpdv = dv;
534 			dumpdev = makedev(majdev, device_unit(dumpdv));
535 		} else {
536 			dumpdv = rootdv;
537 			dumpdev = MAKEDISKDEV(major(rootdev),
538 			    device_unit(dumpdv), 1);
539 		}
540 	}
541 
542 	dumpcdev = devsw_blk2chr(dumpdev);
543 	aprint_normal(" dumps on %s", device_xname(dumpdv));
544 	if (DEV_USES_PARTITIONS(dumpdv))
545 		aprint_normal("%c", (int)DISKPART(dumpdev) + 'a');
546 	aprint_normal("\n");
547 	return;
548 
549  nodumpdev:
550 	dumpdev = NODEV;
551 	dumpcdev = NODEV;
552 	aprint_normal("\n");
553 }
554 
555 static device_t
556 finddevice(const char *name)
557 {
558 	const char *wname;
559 
560 	if ((wname = getwedgename(name, strlen(name))) != NULL)
561 		return dkwedge_find_by_wname(wname);
562 
563 	return device_find_by_xname(name);
564 }
565 
566 static device_t
567 getdisk(char *str, int len, int defpart, dev_t *devp, int isdump)
568 {
569 	device_t dv;
570 	deviter_t di;
571 
572 	if ((dv = parsedisk(str, len, defpart, devp)) == NULL) {
573 		printf("use one of:");
574 		for (dv = deviter_first(&di, DEVITER_F_ROOT_FIRST); dv != NULL;
575 		     dv = deviter_next(&di)) {
576 			if (DEV_USES_PARTITIONS(dv))
577 				printf(" %s[a-%c]", device_xname(dv),
578 				    'a' + MAXPARTITIONS - 1);
579 			else if (device_class(dv) == DV_DISK)
580 				printf(" %s", device_xname(dv));
581 			if (isdump == 0 && device_class(dv) == DV_IFNET)
582 				printf(" %s", device_xname(dv));
583 		}
584 		deviter_release(&di);
585 		dkwedge_print_wnames();
586 		if (isdump)
587 			printf(" none");
588 #if defined(DDB)
589 		printf(" ddb");
590 #endif
591 		printf(" halt reboot\n");
592 	}
593 	return dv;
594 }
595 
596 static const char *
597 getwedgename(const char *name, int namelen)
598 {
599 	const char *wpfx = "wedge:";
600 	const int wpfxlen = strlen(wpfx);
601 
602 	if (namelen < wpfxlen || strncmp(name, wpfx, wpfxlen) != 0)
603 		return NULL;
604 
605 	return name + wpfxlen;
606 }
607 
608 static device_t
609 parsedisk(char *str, int len, int defpart, dev_t *devp)
610 {
611 	device_t dv;
612 	const char *wname;
613 	char *cp, c;
614 	int majdev, part;
615 	if (len == 0)
616 		return (NULL);
617 
618 	if (len == 4 && strcmp(str, "halt") == 0)
619 		cpu_reboot(RB_HALT, NULL);
620 	else if (len == 6 && strcmp(str, "reboot") == 0)
621 		cpu_reboot(0, NULL);
622 #if defined(DDB)
623 	else if (len == 3 && strcmp(str, "ddb") == 0)
624 		console_debugger();
625 #endif
626 
627 	cp = str + len - 1;
628 	c = *cp;
629 
630 	if ((wname = getwedgename(str, len)) != NULL) {
631 		if ((dv = dkwedge_find_by_wname(wname)) == NULL)
632 			return NULL;
633 		part = defpart;
634 		goto gotdisk;
635 	} else if (c >= 'a' && c <= ('a' + MAXPARTITIONS - 1)) {
636 		part = c - 'a';
637 		*cp = '\0';
638 	} else
639 		part = defpart;
640 
641 	dv = finddevice(str);
642 	if (dv != NULL) {
643 		if (device_class(dv) == DV_DISK) {
644  gotdisk:
645 			majdev = devsw_name2blk(device_xname(dv), NULL, 0);
646 			if (majdev < 0)
647 				panic("parsedisk");
648 			if (DEV_USES_PARTITIONS(dv))
649 				*devp = MAKEDISKDEV(majdev, device_unit(dv),
650 						    part);
651 			else
652 				*devp = makedev(majdev, device_unit(dv));
653 		}
654 
655 		if (device_class(dv) == DV_IFNET)
656 			*devp = NODEV;
657 	}
658 
659 	*cp = c;
660 	return (dv);
661 }
662