xref: /openbsd-src/sys/kern/subr_disk.c (revision cd1eb269cafb12c415be1749cd4a4b5422710415)
1 /*	$OpenBSD: subr_disk.c,v 1.103 2010/05/03 15:27:28 jsing Exp $	*/
2 /*	$NetBSD: subr_disk.c,v 1.17 1996/03/16 23:17:08 christos Exp $	*/
3 
4 /*
5  * Copyright (c) 1995 Jason R. Thorpe.  All rights reserved.
6  * Copyright (c) 1982, 1986, 1988, 1993
7  *	The Regents of the University of California.  All rights reserved.
8  * (c) UNIX System Laboratories, Inc.
9  * All or some portions of this file are derived from material licensed
10  * to the University of California by American Telephone and Telegraph
11  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
12  * the permission of UNIX System Laboratories, Inc.
13  *
14  * Redistribution and use in source and binary forms, with or without
15  * modification, are permitted provided that the following conditions
16  * are met:
17  * 1. Redistributions of source code must retain the above copyright
18  *    notice, this list of conditions and the following disclaimer.
19  * 2. Redistributions in binary form must reproduce the above copyright
20  *    notice, this list of conditions and the following disclaimer in the
21  *    documentation and/or other materials provided with the distribution.
22  * 3. Neither the name of the University nor the names of its contributors
23  *    may be used to endorse or promote products derived from this software
24  *    without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36  * SUCH DAMAGE.
37  *
38  *	@(#)ufs_disksubr.c	8.5 (Berkeley) 1/21/94
39  */
40 
41 #include <sys/param.h>
42 #include <sys/systm.h>
43 #include <sys/kernel.h>
44 #include <sys/malloc.h>
45 #include <sys/fcntl.h>
46 #include <sys/buf.h>
47 #include <sys/stat.h>
48 #include <sys/syslog.h>
49 #include <sys/device.h>
50 #include <sys/time.h>
51 #include <sys/disklabel.h>
52 #include <sys/conf.h>
53 #include <sys/lock.h>
54 #include <sys/disk.h>
55 #include <sys/reboot.h>
56 #include <sys/dkio.h>
57 #include <sys/dkstat.h>		/* XXX */
58 #include <sys/proc.h>
59 #include <sys/vnode.h>
60 #include <uvm/uvm_extern.h>
61 
62 #include <sys/socket.h>
63 #include <sys/socketvar.h>
64 
65 #include <net/if.h>
66 
67 #include <dev/rndvar.h>
68 #include <dev/cons.h>
69 
70 /*
71  * A global list of all disks attached to the system.  May grow or
72  * shrink over time.
73  */
74 struct	disklist_head disklist;	/* TAILQ_HEAD */
75 int	disk_count;		/* number of drives in global disklist */
76 int	disk_change;		/* set if a disk has been attached/detached
77 				 * since last we looked at this variable. This
78 				 * is reset by hw_sysctl()
79 				 */
80 
81 /* softraid callback, do not use! */
82 void (*softraid_disk_attach)(struct disk *, int);
83 
84 /*
85  * Seek sort for disks.  We depend on the driver which calls us using b_resid
86  * as the current cylinder number.
87  *
88  * The argument ap structure holds a b_actf activity chain pointer on which we
89  * keep two queues, sorted in ascending cylinder order.  The first queue holds
90  * those requests which are positioned after the current cylinder (in the first
91  * request); the second holds requests which came in after their cylinder number
92  * was passed.  Thus we implement a one way scan, retracting after reaching the
93  * end of the drive to the first request on the second queue, at which time it
94  * becomes the first queue.
95  *
96  * A one-way scan is natural because of the way UNIX read-ahead blocks are
97  * allocated.
98  */
99 
100 void
101 disksort(struct buf *ap, struct buf *bp)
102 {
103 	struct buf *bq;
104 
105 	/* If the queue is empty, then it's easy. */
106 	if (ap->b_actf == NULL) {
107 		bp->b_actf = NULL;
108 		ap->b_actf = bp;
109 		return;
110 	}
111 
112 	/*
113 	 * If we lie after the first (currently active) request, then we
114 	 * must locate the second request list and add ourselves to it.
115 	 */
116 	bq = ap->b_actf;
117 	if (bp->b_cylinder < bq->b_cylinder) {
118 		while (bq->b_actf) {
119 			/*
120 			 * Check for an ``inversion'' in the normally ascending
121 			 * cylinder numbers, indicating the start of the second
122 			 * request list.
123 			 */
124 			if (bq->b_actf->b_cylinder < bq->b_cylinder) {
125 				/*
126 				 * Search the second request list for the first
127 				 * request at a larger cylinder number.  We go
128 				 * before that; if there is no such request, we
129 				 * go at end.
130 				 */
131 				do {
132 					if (bp->b_cylinder <
133 					    bq->b_actf->b_cylinder)
134 						goto insert;
135 					if (bp->b_cylinder ==
136 					    bq->b_actf->b_cylinder &&
137 					    bp->b_blkno < bq->b_actf->b_blkno)
138 						goto insert;
139 					bq = bq->b_actf;
140 				} while (bq->b_actf);
141 				goto insert;		/* after last */
142 			}
143 			bq = bq->b_actf;
144 		}
145 		/*
146 		 * No inversions... we will go after the last, and
147 		 * be the first request in the second request list.
148 		 */
149 		goto insert;
150 	}
151 	/*
152 	 * Request is at/after the current request...
153 	 * sort in the first request list.
154 	 */
155 	while (bq->b_actf) {
156 		/*
157 		 * We want to go after the current request if there is an
158 		 * inversion after it (i.e. it is the end of the first
159 		 * request list), or if the next request is a larger cylinder
160 		 * than our request.
161 		 */
162 		if (bq->b_actf->b_cylinder < bq->b_cylinder ||
163 		    bp->b_cylinder < bq->b_actf->b_cylinder ||
164 		    (bp->b_cylinder == bq->b_actf->b_cylinder &&
165 		    bp->b_blkno < bq->b_actf->b_blkno))
166 			goto insert;
167 		bq = bq->b_actf;
168 	}
169 	/*
170 	 * Neither a second list nor a larger request... we go at the end of
171 	 * the first list, which is the same as the end of the whole schebang.
172 	 */
173 insert:	bp->b_actf = bq->b_actf;
174 	bq->b_actf = bp;
175 }
176 
177 /*
178  * Compute checksum for disk label.
179  */
180 u_int
181 dkcksum(struct disklabel *lp)
182 {
183 	u_int16_t *start, *end;
184 	u_int16_t sum = 0;
185 
186 	start = (u_int16_t *)lp;
187 	end = (u_int16_t *)&lp->d_partitions[lp->d_npartitions];
188 	while (start < end)
189 		sum ^= *start++;
190 	return (sum);
191 }
192 
193 int
194 initdisklabel(struct disklabel *lp)
195 {
196 	int i;
197 
198 	/* minimal requirements for archetypal disk label */
199 	if (lp->d_secsize < DEV_BSIZE)
200 		lp->d_secsize = DEV_BSIZE;
201 	if (DL_GETDSIZE(lp) == 0)
202 		DL_SETDSIZE(lp, MAXDISKSIZE);
203 	if (lp->d_secpercyl == 0)
204 		return (ERANGE);
205 	lp->d_npartitions = MAXPARTITIONS;
206 	for (i = 0; i < RAW_PART; i++) {
207 		DL_SETPSIZE(&lp->d_partitions[i], 0);
208 		DL_SETPOFFSET(&lp->d_partitions[i], 0);
209 	}
210 	if (DL_GETPSIZE(&lp->d_partitions[RAW_PART]) == 0)
211 		DL_SETPSIZE(&lp->d_partitions[RAW_PART], DL_GETDSIZE(lp));
212 	DL_SETPOFFSET(&lp->d_partitions[RAW_PART], 0);
213 	DL_SETBSTART(lp, 0);
214 	DL_SETBEND(lp, DL_GETDSIZE(lp));
215 	lp->d_version = 1;
216 	lp->d_bbsize = 8192;
217 	lp->d_sbsize = 64*1024;			/* XXX ? */
218 	return (0);
219 }
220 
221 /*
222  * Check an incoming block to make sure it is a disklabel, convert it to
223  * a newer version if needed, etc etc.
224  */
225 int
226 checkdisklabel(void *rlp, struct disklabel *lp,
227 	u_int64_t boundstart, u_int64_t boundend)
228 {
229 	struct disklabel *dlp = rlp;
230 	struct __partitionv0 *v0pp;
231 	struct partition *pp;
232 	daddr64_t disksize;
233 	int error = 0;
234 	int i;
235 
236 	if (dlp->d_magic != DISKMAGIC || dlp->d_magic2 != DISKMAGIC)
237 		error = ENOENT;	/* no disk label */
238 	else if (dlp->d_npartitions > MAXPARTITIONS)
239 		error = E2BIG;	/* too many partitions */
240 	else if (dlp->d_secpercyl == 0)
241 		error = EINVAL;	/* invalid label */
242 	else if (dlp->d_secsize == 0)
243 		error = ENOSPC;	/* disk too small */
244 	else if (dkcksum(dlp) != 0)
245 		error = EINVAL;	/* incorrect checksum */
246 
247 	if (error) {
248 		u_int16_t *start, *end, sum = 0;
249 
250 		/* If it is byte-swapped, attempt to convert it */
251 		if (swap32(dlp->d_magic) != DISKMAGIC ||
252 		    swap32(dlp->d_magic2) != DISKMAGIC ||
253 		    swap16(dlp->d_npartitions) > MAXPARTITIONS)
254 			return (error);
255 
256 		/*
257 		 * Need a byte-swap aware dkcksum variant
258 		 * inlined, because dkcksum uses a sub-field
259 		 */
260 		start = (u_int16_t *)dlp;
261 		end = (u_int16_t *)&dlp->d_partitions[
262 		    swap16(dlp->d_npartitions)];
263 		while (start < end)
264 			sum ^= *start++;
265 		if (sum != 0)
266 			return (error);
267 
268 		dlp->d_magic = swap32(dlp->d_magic);
269 		dlp->d_type = swap16(dlp->d_type);
270 		dlp->d_subtype = swap16(dlp->d_subtype);
271 
272 		/* d_typename and d_packname are strings */
273 
274 		dlp->d_secsize = swap32(dlp->d_secsize);
275 		dlp->d_nsectors = swap32(dlp->d_nsectors);
276 		dlp->d_ntracks = swap32(dlp->d_ntracks);
277 		dlp->d_ncylinders = swap32(dlp->d_ncylinders);
278 		dlp->d_secpercyl = swap32(dlp->d_secpercyl);
279 		dlp->d_secperunit = swap32(dlp->d_secperunit);
280 
281 		/* d_uid is a string */
282 
283 		dlp->d_acylinders = swap32(dlp->d_acylinders);
284 
285 		dlp->d_flags = swap32(dlp->d_flags);
286 
287 		for (i = 0; i < NDDATA; i++)
288 			dlp->d_drivedata[i] = swap32(dlp->d_drivedata[i]);
289 
290 		dlp->d_secperunith = swap16(dlp->d_secperunith);
291 		dlp->d_version = swap16(dlp->d_version);
292 
293 		for (i = 0; i < NSPARE; i++)
294 			dlp->d_spare[i] = swap32(dlp->d_spare[i]);
295 
296 		dlp->d_magic2 = swap32(dlp->d_magic2);
297 		dlp->d_checksum = swap16(dlp->d_checksum);
298 
299 		dlp->d_npartitions = swap16(dlp->d_npartitions);
300 		dlp->d_bbsize = swap32(dlp->d_bbsize);
301 		dlp->d_sbsize = swap32(dlp->d_sbsize);
302 
303 		for (i = 0; i < MAXPARTITIONS; i++) {
304 			pp = &dlp->d_partitions[i];
305 			pp->p_size = swap32(pp->p_size);
306 			pp->p_offset = swap32(pp->p_offset);
307 			if (dlp->d_version == 0) {
308 				v0pp = (struct __partitionv0 *)pp;
309 				v0pp->p_fsize = swap32(v0pp->p_fsize);
310 			} else {
311 				pp->p_offseth = swap16(pp->p_offseth);
312 				pp->p_sizeh = swap16(pp->p_sizeh);
313 			}
314 			pp->p_cpg = swap16(pp->p_cpg);
315 		}
316 
317 		dlp->d_checksum = 0;
318 		dlp->d_checksum = dkcksum(dlp);
319 		error = 0;
320 	}
321 
322 	/* XXX should verify lots of other fields and whine a lot */
323 
324 	if (error)
325 		return (error);
326 
327 	/* Initial passed in lp contains the real disk size. */
328 	disksize = DL_GETDSIZE(lp);
329 
330 	if (lp != dlp)
331 		*lp = *dlp;
332 
333 	if (lp->d_version == 0) {
334 		lp->d_version = 1;
335 		lp->d_secperunith = 0;
336 
337 		v0pp = (struct __partitionv0 *)lp->d_partitions;
338 		pp = lp->d_partitions;
339 		for (i = 0; i < lp->d_npartitions; i++, pp++, v0pp++) {
340 			pp->p_fragblock = DISKLABELV1_FFS_FRAGBLOCK(v0pp->
341 			    p_fsize, v0pp->p_frag);
342 			pp->p_offseth = 0;
343 			pp->p_sizeh = 0;
344 		}
345 	}
346 
347 #ifdef DEBUG
348 	if (DL_GETDSIZE(lp) != disksize)
349 		printf("on-disk disklabel has incorrect disksize (%lld)\n",
350 		    DL_GETDSIZE(lp));
351 	if (DL_GETPSIZE(&lp->d_partitions[RAW_PART]) != disksize)
352 		printf("on-disk disklabel RAW_PART has incorrect size (%lld)\n",
353 		    DL_GETPSIZE(&lp->d_partitions[RAW_PART]));
354 	if (DL_GETPOFFSET(&lp->d_partitions[RAW_PART]) != 0)
355 		printf("on-disk disklabel RAW_PART offset != 0 (%lld)\n",
356 		    DL_GETPOFFSET(&lp->d_partitions[RAW_PART]));
357 #endif
358 	DL_SETDSIZE(lp, disksize);
359 	DL_SETPSIZE(&lp->d_partitions[RAW_PART], disksize);
360 	DL_SETPOFFSET(&lp->d_partitions[RAW_PART], 0);
361 	DL_SETBSTART(lp, boundstart);
362 	DL_SETBEND(lp, boundend < DL_GETDSIZE(lp) ? boundend : DL_GETDSIZE(lp));
363 
364 	lp->d_checksum = 0;
365 	lp->d_checksum = dkcksum(lp);
366 	return (0);
367 }
368 
369 /*
370  * If dos partition table requested, attempt to load it and
371  * find disklabel inside a DOS partition. Return buffer
372  * for use in signalling errors if requested.
373  *
374  * We would like to check if each MBR has a valid BOOT_MAGIC, but
375  * we cannot because it doesn't always exist. So.. we assume the
376  * MBR is valid.
377  */
378 int
379 readdoslabel(struct buf *bp, void (*strat)(struct buf *),
380     struct disklabel *lp, int *partoffp, int spoofonly)
381 {
382 	u_int64_t dospartoff = 0, dospartend = DL_GETBEND(lp);
383 	int i, ourpart = -1, wander = 1, n = 0, loop = 0, offset;
384 	struct dos_partition dp[NDOSPART], *dp2;
385 	daddr64_t part_blkno = DOSBBSECTOR;
386 	u_int32_t extoff = 0;
387 	int error;
388 
389 	if (lp->d_secpercyl == 0)
390 		return (EINVAL);	/* invalid label */
391 	if (lp->d_secsize == 0)
392 		return (ENOSPC);	/* disk too small */
393 
394 	/* do DOS partitions in the process of getting disklabel? */
395 
396 	/*
397 	 * Read dos partition table, follow extended partitions.
398 	 * Map the partitions to disklabel entries i-p
399 	 */
400 	while (wander && n < 8 && loop < 8) {
401 		loop++;
402 		wander = 0;
403 		if (part_blkno < extoff)
404 			part_blkno = extoff;
405 
406 		/* read boot record */
407 		bp->b_blkno = DL_BLKTOSEC(lp, part_blkno) * DL_BLKSPERSEC(lp);
408 		offset = DL_BLKOFFSET(lp, part_blkno) + DOSPARTOFF;
409 		bp->b_bcount = lp->d_secsize;
410 		bp->b_flags = B_BUSY | B_READ | B_RAW;
411 		(*strat)(bp);
412 		error = biowait(bp);
413 		if (error) {
414 /*wrong*/		if (partoffp)
415 /*wrong*/			*partoffp = -1;
416 			return (error);
417 		}
418 
419 		bcopy(bp->b_data + offset, dp, sizeof(dp));
420 
421 		if (n == 0 && part_blkno == DOSBBSECTOR) {
422 			u_int16_t fattest;
423 
424 			/* Check the end of sector marker. */
425 			fattest = ((bp->b_data[510] << 8) & 0xff00) |
426 			    (bp->b_data[511] & 0xff);
427 			if (fattest != 0x55aa)
428 				goto notfat;
429 		}
430 
431 		if (ourpart == -1) {
432 			/* Search for our MBR partition */
433 			for (dp2=dp, i=0; i < NDOSPART && ourpart == -1;
434 			    i++, dp2++)
435 				if (letoh32(dp2->dp_size) &&
436 				    dp2->dp_typ == DOSPTYP_OPENBSD)
437 					ourpart = i;
438 			if (ourpart == -1)
439 				goto donot;
440 			/*
441 			 * This is our MBR partition. need sector
442 			 * address for SCSI/IDE, cylinder for
443 			 * ESDI/ST506/RLL
444 			 */
445 			dp2 = &dp[ourpart];
446 			dospartoff = letoh32(dp2->dp_start) + part_blkno;
447 			dospartend = dospartoff + letoh32(dp2->dp_size);
448 
449 			/* found our OpenBSD partition, finish up */
450 			if (partoffp)
451 				goto notfat;
452 
453 			if (lp->d_ntracks == 0)
454 				lp->d_ntracks = dp2->dp_ehd + 1;
455 			if (lp->d_nsectors == 0)
456 				lp->d_nsectors = DPSECT(dp2->dp_esect);
457 			if (lp->d_secpercyl == 0)
458 				lp->d_secpercyl = lp->d_ntracks *
459 				    lp->d_nsectors;
460 		}
461 donot:
462 		/*
463 		 * In case the disklabel read below fails, we want to
464 		 * provide a fake label in i-p.
465 		 */
466 		for (dp2=dp, i=0; i < NDOSPART && n < 8; i++, dp2++) {
467 			struct partition *pp = &lp->d_partitions[8+n];
468 			u_int8_t fstype;
469 
470 			if (dp2->dp_typ == DOSPTYP_OPENBSD)
471 				continue;
472 			if (letoh32(dp2->dp_size) > DL_GETDSIZE(lp))
473 				continue;
474 			if (letoh32(dp2->dp_start) > DL_GETDSIZE(lp))
475 				continue;
476 			if (letoh32(dp2->dp_size) == 0)
477 				continue;
478 
479 			switch (dp2->dp_typ) {
480 			case DOSPTYP_UNUSED:
481 				fstype = FS_UNUSED;
482 				n++;
483 				break;
484 
485 			case DOSPTYP_LINUX:
486 				fstype = FS_EXT2FS;
487 				n++;
488 				break;
489 
490 			case DOSPTYP_NTFS:
491 				fstype = FS_NTFS;
492 				n++;
493 				break;
494 
495 			case DOSPTYP_FAT12:
496 			case DOSPTYP_FAT16S:
497 			case DOSPTYP_FAT16B:
498 			case DOSPTYP_FAT16L:
499 			case DOSPTYP_FAT32:
500 			case DOSPTYP_FAT32L:
501 				fstype = FS_MSDOS;
502 				n++;
503 				break;
504 			case DOSPTYP_EXTEND:
505 			case DOSPTYP_EXTENDL:
506 				part_blkno = letoh32(dp2->dp_start) + extoff;
507 				if (!extoff) {
508 					extoff = letoh32(dp2->dp_start);
509 					part_blkno = 0;
510 				}
511 				wander = 1;
512 				continue;
513 				break;
514 			default:
515 				fstype = FS_OTHER;
516 				n++;
517 				break;
518 			}
519 
520 			/*
521 			 * Don't set fstype/offset/size when just looking for
522 			 * the offset of the OpenBSD partition. It would
523 			 * invalidate the disklabel checksum!
524 			 */
525 			if (partoffp)
526 				continue;
527 
528 			pp->p_fstype = fstype;
529 			if (letoh32(dp2->dp_start))
530 				DL_SETPOFFSET(pp,
531 				    letoh32(dp2->dp_start) + part_blkno);
532 			DL_SETPSIZE(pp, letoh32(dp2->dp_size));
533 		}
534 	}
535 	if (partoffp)
536 		/* dospartoff has been set and we must not modify *lp. */
537 		goto notfat;
538 
539 	lp->d_npartitions = MAXPARTITIONS;
540 
541 	if (n == 0 && part_blkno == DOSBBSECTOR) {
542 		u_int16_t fattest;
543 
544 		/* Check for a valid initial jmp instruction. */
545 		switch ((u_int8_t)bp->b_data[0]) {
546 		case 0xeb:
547 			/*
548 			 * Two-byte jmp instruction. The 2nd byte is the number
549 			 * of bytes to jmp and the 3rd byte must be a NOP.
550 			 */
551 			if ((u_int8_t)bp->b_data[2] != 0x90)
552 				goto notfat;
553 			break;
554 		case 0xe9:
555 			/*
556 			 * Three-byte jmp instruction. The next two bytes are a
557 			 * little-endian 16 bit value.
558 			 */
559 			break;
560 		default:
561 			goto notfat;
562 			break;
563 		}
564 
565 		/* Check for a valid bytes per sector value. */
566 		fattest = ((bp->b_data[12] << 8) & 0xff00) |
567 		    (bp->b_data[11] & 0xff);
568 		if (fattest < 512 || fattest > 4096 || (fattest % 512 != 0))
569 			goto notfat;
570 
571 		/* Looks like a FAT filesystem. Spoof 'i'. */
572 		DL_SETPSIZE(&lp->d_partitions['i' - 'a'],
573 		    DL_GETPSIZE(&lp->d_partitions[RAW_PART]));
574 		DL_SETPOFFSET(&lp->d_partitions['i' - 'a'], 0);
575 		lp->d_partitions['i' - 'a'].p_fstype = FS_MSDOS;
576 	}
577 notfat:
578 	/* record the OpenBSD partition's placement for the caller */
579 	if (partoffp)
580 		*partoffp = dospartoff;
581 	else {
582 		DL_SETBSTART(lp, dospartoff);
583 		DL_SETBEND(lp,
584 		    dospartend < DL_GETDSIZE(lp) ? dospartend : DL_GETDSIZE(lp));
585 	}
586 
587 	/* don't read the on-disk label if we are in spoofed-only mode */
588 	if (spoofonly)
589 		return (0);
590 
591 	bp->b_blkno = DL_BLKTOSEC(lp, dospartoff + DOS_LABELSECTOR) *
592 	    DL_BLKSPERSEC(lp);
593 	offset = DL_BLKOFFSET(lp, dospartoff + DOS_LABELSECTOR);
594 	bp->b_bcount = lp->d_secsize;
595 	bp->b_flags = B_BUSY | B_READ | B_RAW;
596 	(*strat)(bp);
597 	if (biowait(bp))
598 		return (bp->b_error);
599 
600 	/* sub-MBR disklabels are always at a LABELOFFSET of 0 */
601 	return checkdisklabel(bp->b_data + offset, lp, dospartoff, dospartend);
602 }
603 
604 /*
605  * Check new disk label for sensibility before setting it.
606  */
607 int
608 setdisklabel(struct disklabel *olp, struct disklabel *nlp, u_int openmask)
609 {
610 	struct partition *opp, *npp;
611 	struct disk *dk;
612 	u_int64_t uid;
613 	int i;
614 
615 	/* sanity clause */
616 	if (nlp->d_secpercyl == 0 || nlp->d_secsize == 0 ||
617 	    (nlp->d_secsize % DEV_BSIZE) != 0)
618 		return (EINVAL);
619 
620 	/* special case to allow disklabel to be invalidated */
621 	if (nlp->d_magic == 0xffffffff) {
622 		*olp = *nlp;
623 		return (0);
624 	}
625 
626 	if (nlp->d_magic != DISKMAGIC || nlp->d_magic2 != DISKMAGIC ||
627 	    dkcksum(nlp) != 0)
628 		return (EINVAL);
629 
630 	/* XXX missing check if other dos partitions will be overwritten */
631 
632 	while (openmask != 0) {
633 		i = ffs(openmask) - 1;
634 		openmask &= ~(1 << i);
635 		if (nlp->d_npartitions <= i)
636 			return (EBUSY);
637 		opp = &olp->d_partitions[i];
638 		npp = &nlp->d_partitions[i];
639 		if (DL_GETPOFFSET(npp) != DL_GETPOFFSET(opp) ||
640 		    DL_GETPSIZE(npp) < DL_GETPSIZE(opp))
641 			return (EBUSY);
642 		/*
643 		 * Copy internally-set partition information
644 		 * if new label doesn't include it.		XXX
645 		 */
646 		if (npp->p_fstype == FS_UNUSED && opp->p_fstype != FS_UNUSED) {
647 			npp->p_fstype = opp->p_fstype;
648 			npp->p_fragblock = opp->p_fragblock;
649 			npp->p_cpg = opp->p_cpg;
650 		}
651 	}
652 
653 	/* Generate a UID if the disklabel does not already have one. */
654 	uid = 0;
655 	if (bcmp(nlp->d_uid, &uid, sizeof(nlp->d_uid)) == 0) {
656 		do {
657 			arc4random_buf(nlp->d_uid, sizeof(nlp->d_uid));
658 			TAILQ_FOREACH(dk, &disklist, dk_link)
659 				if (dk->dk_label && bcmp(dk->dk_label->d_uid,
660 				    nlp->d_uid, sizeof(nlp->d_uid)) == 0)
661 					break;
662 		} while (dk != NULL);
663 	}
664 
665 	nlp->d_checksum = 0;
666 	nlp->d_checksum = dkcksum(nlp);
667 	*olp = *nlp;
668 	return (0);
669 }
670 
671 /*
672  * Determine the size of the transfer, and make sure it is within the
673  * boundaries of the partition. Adjust transfer if needed, and signal errors or
674  * early completion.
675  */
676 int
677 bounds_check_with_label(struct buf *bp, struct disklabel *lp, int wlabel)
678 {
679 	struct partition *p = &lp->d_partitions[DISKPART(bp->b_dev)];
680 	daddr64_t sz = howmany(bp->b_bcount, DEV_BSIZE);
681 
682 	/* Avoid division by zero, negative offsets and negative sizes. */
683 	if (lp->d_secpercyl == 0 || bp->b_blkno < 0 || sz < 0)
684 		goto bad;
685 
686 	/* beyond partition? */
687 	if (bp->b_blkno + sz > DL_SECTOBLK(lp, DL_GETPSIZE(p))) {
688 		sz = DL_SECTOBLK(lp, DL_GETPSIZE(p)) - bp->b_blkno;
689 		if (sz == 0) {
690 			/* If exactly at end of disk, return EOF. */
691 			bp->b_resid = bp->b_bcount;
692 			return (-1);
693 		}
694 		if (sz < 0)
695 			/* If past end of disk, return EINVAL. */
696 			goto bad;
697 
698 		/* Otherwise, truncate request. */
699 		bp->b_bcount = sz << DEV_BSHIFT;
700 	}
701 
702 	/* calculate cylinder for disksort to order transfers with */
703 	bp->b_cylinder = (bp->b_blkno + DL_SECTOBLK(lp, DL_GETPOFFSET(p))) /
704 	    DL_SECTOBLK(lp, lp->d_secpercyl);
705 	return (1);
706 
707 bad:
708 	bp->b_error = EINVAL;
709 	bp->b_flags |= B_ERROR;
710 	return (-1);
711 }
712 
713 /*
714  * Disk error is the preface to plaintive error messages
715  * about failing disk transfers.  It prints messages of the form
716 
717 hp0g: hard error reading fsbn 12345 of 12344-12347 (hp0 bn %d cn %d tn %d sn %d)
718 
719  * if the offset of the error in the transfer and a disk label
720  * are both available.  blkdone should be -1 if the position of the error
721  * is unknown; the disklabel pointer may be null from drivers that have not
722  * been converted to use them.  The message is printed with printf
723  * if pri is LOG_PRINTF, otherwise it uses log at the specified priority.
724  * The message should be completed (with at least a newline) with printf
725  * or addlog, respectively.  There is no trailing space.
726  */
727 void
728 diskerr(struct buf *bp, char *dname, char *what, int pri, int blkdone,
729     struct disklabel *lp)
730 {
731 	int unit = DISKUNIT(bp->b_dev), part = DISKPART(bp->b_dev);
732 	int (*pr)(const char *, ...);
733 	char partname = 'a' + part;
734 	daddr64_t sn;
735 
736 	if (pri != LOG_PRINTF) {
737 		static const char fmt[] = "";
738 		log(pri, fmt);
739 		pr = addlog;
740 	} else
741 		pr = printf;
742 	(*pr)("%s%d%c: %s %sing fsbn ", dname, unit, partname, what,
743 	    bp->b_flags & B_READ ? "read" : "writ");
744 	sn = bp->b_blkno;
745 	if (bp->b_bcount <= DEV_BSIZE)
746 		(*pr)("%lld", sn);
747 	else {
748 		if (blkdone >= 0) {
749 			sn += blkdone;
750 			(*pr)("%lld of ", sn);
751 		}
752 		(*pr)("%lld-%lld", bp->b_blkno,
753 		    bp->b_blkno + (bp->b_bcount - 1) / DEV_BSIZE);
754 	}
755 	if (lp && (blkdone >= 0 || bp->b_bcount <= lp->d_secsize)) {
756 		sn += DL_GETPOFFSET(&lp->d_partitions[part]);
757 		(*pr)(" (%s%d bn %lld; cn %lld", dname, unit, sn,
758 		    sn / lp->d_secpercyl);
759 		sn %= lp->d_secpercyl;
760 		(*pr)(" tn %lld sn %lld)", sn / lp->d_nsectors,
761 		    sn % lp->d_nsectors);
762 	}
763 }
764 
765 /*
766  * Initialize the disklist.  Called by main() before autoconfiguration.
767  */
768 void
769 disk_init(void)
770 {
771 
772 	TAILQ_INIT(&disklist);
773 	disk_count = disk_change = 0;
774 }
775 
776 int
777 disk_construct(struct disk *diskp, char *lockname)
778 {
779 	rw_init(&diskp->dk_lock, "dklk");
780 	mtx_init(&diskp->dk_mtx, IPL_BIO);
781 
782 	diskp->dk_flags |= DKF_CONSTRUCTED;
783 
784 	return (0);
785 }
786 
787 /*
788  * Attach a disk.
789  */
790 void
791 disk_attach(struct disk *diskp)
792 {
793 
794 	if (!ISSET(diskp->dk_flags, DKF_CONSTRUCTED))
795 		disk_construct(diskp, diskp->dk_name);
796 
797 	/*
798 	 * Allocate and initialize the disklabel structures.  Note that
799 	 * it's not safe to sleep here, since we're probably going to be
800 	 * called during autoconfiguration.
801 	 */
802 	diskp->dk_label = malloc(sizeof(struct disklabel), M_DEVBUF,
803 	    M_NOWAIT|M_ZERO);
804 	if (diskp->dk_label == NULL)
805 		panic("disk_attach: can't allocate storage for disklabel");
806 
807 	/*
808 	 * Set the attached timestamp.
809 	 */
810 	microuptime(&diskp->dk_attachtime);
811 
812 	/*
813 	 * Link into the disklist.
814 	 */
815 	TAILQ_INSERT_TAIL(&disklist, diskp, dk_link);
816 	++disk_count;
817 	disk_change = 1;
818 
819 	if (softraid_disk_attach)
820 		softraid_disk_attach(diskp, 1);
821 }
822 
823 /*
824  * Detach a disk.
825  */
826 void
827 disk_detach(struct disk *diskp)
828 {
829 
830 	if (softraid_disk_attach)
831 		softraid_disk_attach(diskp, -1);
832 
833 	/*
834 	 * Free the space used by the disklabel structures.
835 	 */
836 	free(diskp->dk_label, M_DEVBUF);
837 
838 	/*
839 	 * Remove from the disklist.
840 	 */
841 	TAILQ_REMOVE(&disklist, diskp, dk_link);
842 	disk_change = 1;
843 	if (--disk_count < 0)
844 		panic("disk_detach: disk_count < 0");
845 }
846 
847 /*
848  * Increment a disk's busy counter.  If the counter is going from
849  * 0 to 1, set the timestamp.
850  */
851 void
852 disk_busy(struct disk *diskp)
853 {
854 
855 	/*
856 	 * XXX We'd like to use something as accurate as microtime(),
857 	 * but that doesn't depend on the system TOD clock.
858 	 */
859 	mtx_enter(&diskp->dk_mtx);
860 	if (diskp->dk_busy++ == 0)
861 		microuptime(&diskp->dk_timestamp);
862 	mtx_leave(&diskp->dk_mtx);
863 }
864 
865 /*
866  * Decrement a disk's busy counter, increment the byte count, total busy
867  * time, and reset the timestamp.
868  */
869 void
870 disk_unbusy(struct disk *diskp, long bcount, int read)
871 {
872 	struct timeval dv_time, diff_time;
873 
874 	mtx_enter(&diskp->dk_mtx);
875 
876 	if (diskp->dk_busy-- == 0)
877 		printf("disk_unbusy: %s: dk_busy < 0\n", diskp->dk_name);
878 
879 	microuptime(&dv_time);
880 
881 	timersub(&dv_time, &diskp->dk_timestamp, &diff_time);
882 	timeradd(&diskp->dk_time, &diff_time, &diskp->dk_time);
883 
884 	diskp->dk_timestamp = dv_time;
885 	if (bcount > 0) {
886 		if (read) {
887 			diskp->dk_rbytes += bcount;
888 			diskp->dk_rxfer++;
889 		} else {
890 			diskp->dk_wbytes += bcount;
891 			diskp->dk_wxfer++;
892 		}
893 	} else
894 		diskp->dk_seek++;
895 
896 	mtx_leave(&diskp->dk_mtx);
897 
898 	add_disk_randomness(bcount ^ diff_time.tv_usec);
899 }
900 
901 int
902 disk_lock(struct disk *dk)
903 {
904 	int error;
905 
906 	error = rw_enter(&dk->dk_lock, RW_WRITE|RW_INTR);
907 
908 	return (error);
909 }
910 
911 void
912 disk_unlock(struct disk *dk)
913 {
914 	rw_exit(&dk->dk_lock);
915 }
916 
917 int
918 dk_mountroot(void)
919 {
920 	dev_t rawdev, rrootdev;
921 	int part = DISKPART(rootdev);
922 	int (*mountrootfn)(void);
923 	struct disklabel dl;
924 	struct vnode *vn;
925 	int error;
926 
927 	rrootdev = blktochr(rootdev);
928 	rawdev = MAKEDISKDEV(major(rrootdev), DISKUNIT(rootdev), RAW_PART);
929 #ifdef DEBUG
930 	printf("rootdev=0x%x rrootdev=0x%x rawdev=0x%x\n", rootdev,
931 	    rrootdev, rawdev);
932 #endif
933 
934 	/*
935 	 * open device, ioctl for the disklabel, and close it.
936 	 */
937 	if (cdevvp(rawdev, &vn))
938 		panic("cannot obtain vnode for 0x%x/0x%x", rootdev, rrootdev);
939 	error = VOP_OPEN(vn, FREAD, NOCRED, curproc);
940 	if (error)
941 		panic("cannot open disk, 0x%x/0x%x, error %d",
942 		    rootdev, rrootdev, error);
943 	error = VOP_IOCTL(vn, DIOCGDINFO, (caddr_t)&dl, FREAD, NOCRED, 0);
944 	if (error)
945 		panic("cannot read disk label, 0x%x/0x%x, error %d",
946 		    rootdev, rrootdev, error);
947 	error = VOP_CLOSE(vn, FREAD, NOCRED, 0);
948 	if (error)
949 		panic("cannot close disk , 0x%x/0x%x, error %d",
950 		    rootdev, rrootdev, error);
951 	vput(vn);
952 
953 	if (DL_GETPSIZE(&dl.d_partitions[part]) == 0)
954 		panic("root filesystem has size 0");
955 	switch (dl.d_partitions[part].p_fstype) {
956 #ifdef EXT2FS
957 	case FS_EXT2FS:
958 		{
959 		extern int ext2fs_mountroot(void);
960 		mountrootfn = ext2fs_mountroot;
961 		}
962 		break;
963 #endif
964 #ifdef FFS
965 	case FS_BSDFFS:
966 		{
967 		extern int ffs_mountroot(void);
968 		mountrootfn = ffs_mountroot;
969 		}
970 		break;
971 #endif
972 #ifdef CD9660
973 	case FS_ISO9660:
974 		{
975 		extern int cd9660_mountroot(void);
976 		mountrootfn = cd9660_mountroot;
977 		}
978 		break;
979 #endif
980 	default:
981 #ifdef FFS
982 		{
983 		extern int ffs_mountroot(void);
984 
985 		printf("filesystem type %d not known.. assuming ffs\n",
986 		    dl.d_partitions[part].p_fstype);
987 		mountrootfn = ffs_mountroot;
988 		}
989 #else
990 		panic("disk 0x%x/0x%x filesystem type %d not known",
991 		    rootdev, rrootdev, dl.d_partitions[part].p_fstype);
992 #endif
993 	}
994 	return (*mountrootfn)();
995 }
996 
997 struct device *
998 getdisk(char *str, int len, int defpart, dev_t *devp)
999 {
1000 	struct device *dv;
1001 
1002 	if ((dv = parsedisk(str, len, defpart, devp)) == NULL) {
1003 		printf("use one of: exit");
1004 		TAILQ_FOREACH(dv, &alldevs, dv_list) {
1005 			if (dv->dv_class == DV_DISK)
1006 				printf(" %s[a-p]", dv->dv_xname);
1007 #if defined(NFSCLIENT)
1008 			if (dv->dv_class == DV_IFNET)
1009 				printf(" %s", dv->dv_xname);
1010 #endif
1011 		}
1012 		printf("\n");
1013 	}
1014 	return (dv);
1015 }
1016 
1017 struct device *
1018 parsedisk(char *str, int len, int defpart, dev_t *devp)
1019 {
1020 	struct device *dv;
1021 	int majdev, part = defpart;
1022 	char c;
1023 
1024 	if (len == 0)
1025 		return (NULL);
1026 	c = str[len-1];
1027 	if (c >= 'a' && (c - 'a') < MAXPARTITIONS) {
1028 		part = c - 'a';
1029 		len -= 1;
1030 	}
1031 
1032 	TAILQ_FOREACH(dv, &alldevs, dv_list) {
1033 		if (dv->dv_class == DV_DISK &&
1034 		    strncmp(str, dv->dv_xname, len) == 0 &&
1035 		    dv->dv_xname[len] == '\0') {
1036 			majdev = findblkmajor(dv);
1037 			if (majdev < 0)
1038 				panic("parsedisk");
1039 			*devp = MAKEDISKDEV(majdev, dv->dv_unit, part);
1040 			break;
1041 		}
1042 #if defined(NFSCLIENT)
1043 		if (dv->dv_class == DV_IFNET &&
1044 		    strncmp(str, dv->dv_xname, len) == 0 &&
1045 		    dv->dv_xname[len] == '\0') {
1046 			*devp = NODEV;
1047 			break;
1048 		}
1049 #endif
1050 	}
1051 
1052 	return (dv);
1053 }
1054 
1055 void
1056 setroot(struct device *bootdv, int part, int exitflags)
1057 {
1058 	int majdev, unit, len, s;
1059 	struct swdevt *swp;
1060 	struct device *rootdv, *dv;
1061 	dev_t nrootdev, nswapdev = NODEV, temp = NODEV;
1062 	struct ifnet *ifp = NULL;
1063 	char buf[128];
1064 #if defined(NFSCLIENT)
1065 	extern char *nfsbootdevname;
1066 #endif
1067 
1068 	/*
1069 	 * If `swap generic' and we couldn't determine boot device,
1070 	 * ask the user.
1071 	 */
1072 	if (mountroot == NULL && bootdv == NULL)
1073 		boothowto |= RB_ASKNAME;
1074 	if (boothowto & RB_ASKNAME) {
1075 		while (1) {
1076 			printf("root device");
1077 			if (bootdv != NULL) {
1078 				printf(" (default %s", bootdv->dv_xname);
1079 				if (bootdv->dv_class == DV_DISK)
1080 					printf("%c", 'a' + part);
1081 				printf(")");
1082 			}
1083 			printf(": ");
1084 			s = splhigh();
1085 			cnpollc(TRUE);
1086 			len = getsn(buf, sizeof(buf));
1087 			cnpollc(FALSE);
1088 			splx(s);
1089 			if (strcmp(buf, "exit") == 0)
1090 				boot(exitflags);
1091 			if (len == 0 && bootdv != NULL) {
1092 				strlcpy(buf, bootdv->dv_xname, sizeof buf);
1093 				len = strlen(buf);
1094 			}
1095 			if (len > 0 && buf[len - 1] == '*') {
1096 				buf[--len] = '\0';
1097 				dv = getdisk(buf, len, part, &nrootdev);
1098 				if (dv != NULL) {
1099 					rootdv = dv;
1100 					nswapdev = nrootdev;
1101 					goto gotswap;
1102 				}
1103 			}
1104 			dv = getdisk(buf, len, part, &nrootdev);
1105 			if (dv != NULL) {
1106 				rootdv = dv;
1107 				break;
1108 			}
1109 		}
1110 
1111 		if (rootdv->dv_class == DV_IFNET)
1112 			goto gotswap;
1113 
1114 		/* try to build swap device out of new root device */
1115 		while (1) {
1116 			printf("swap device");
1117 			if (rootdv != NULL)
1118 				printf(" (default %s%s)", rootdv->dv_xname,
1119 				    rootdv->dv_class == DV_DISK ? "b" : "");
1120 			printf(": ");
1121 			s = splhigh();
1122 			cnpollc(TRUE);
1123 			len = getsn(buf, sizeof(buf));
1124 			cnpollc(FALSE);
1125 			splx(s);
1126 			if (strcmp(buf, "exit") == 0)
1127 				boot(exitflags);
1128 			if (len == 0 && rootdv != NULL) {
1129 				switch (rootdv->dv_class) {
1130 				case DV_IFNET:
1131 					nswapdev = NODEV;
1132 					break;
1133 				case DV_DISK:
1134 					nswapdev = MAKEDISKDEV(major(nrootdev),
1135 					    DISKUNIT(nrootdev), 1);
1136 					if (nswapdev == nrootdev)
1137 						continue;
1138 					break;
1139 				default:
1140 					break;
1141 				}
1142 				break;
1143 			}
1144 			dv = getdisk(buf, len, 1, &nswapdev);
1145 			if (dv) {
1146 				if (dv->dv_class == DV_IFNET)
1147 					nswapdev = NODEV;
1148 				if (nswapdev == nrootdev)
1149 					continue;
1150 				break;
1151 			}
1152 		}
1153 gotswap:
1154 		rootdev = nrootdev;
1155 		dumpdev = nswapdev;
1156 		swdevt[0].sw_dev = nswapdev;
1157 		swdevt[1].sw_dev = NODEV;
1158 #if defined(NFSCLIENT)
1159 	} else if (mountroot == nfs_mountroot) {
1160 		rootdv = bootdv;
1161 		rootdev = dumpdev = swapdev = NODEV;
1162 #endif
1163 	} else if (mountroot == NULL && rootdev == NODEV) {
1164 		/*
1165 		 * `swap generic'
1166 		 */
1167 		rootdv = bootdv;
1168 		majdev = findblkmajor(rootdv);
1169 		if (majdev >= 0) {
1170 			/*
1171 			 * Root and swap are on the disk.
1172 			 * Assume swap is on partition b.
1173 			 */
1174 			rootdev = MAKEDISKDEV(majdev, rootdv->dv_unit, part);
1175 			nswapdev = MAKEDISKDEV(majdev, rootdv->dv_unit, 1);
1176 		} else {
1177 			/*
1178 			 * Root and swap are on a net.
1179 			 */
1180 			nswapdev = NODEV;
1181 		}
1182 		dumpdev = nswapdev;
1183 		swdevt[0].sw_dev = nswapdev;
1184 		/* swdevt[1].sw_dev = NODEV; */
1185 	} else {
1186 		/* Completely pre-configured, but we want rootdv .. */
1187 		majdev = major(rootdev);
1188 		if (findblkname(majdev) == NULL)
1189 			return;
1190 		unit = DISKUNIT(rootdev);
1191 		part = DISKPART(rootdev);
1192 		snprintf(buf, sizeof buf, "%s%d%c",
1193 		    findblkname(majdev), unit, 'a' + part);
1194 		rootdv = parsedisk(buf, strlen(buf), 0, &nrootdev);
1195 		if (rootdv == NULL)
1196 			panic("root device (%s) not found", buf);
1197 	}
1198 
1199 	if (rootdv && rootdv == bootdv && rootdv->dv_class == DV_IFNET)
1200 		ifp = ifunit(rootdv->dv_xname);
1201 	else if (bootdv && bootdv->dv_class == DV_IFNET)
1202 		ifp = ifunit(bootdv->dv_xname);
1203 
1204 	if (ifp)
1205 		if_addgroup(ifp, "netboot");
1206 
1207 	switch (rootdv->dv_class) {
1208 #if defined(NFSCLIENT)
1209 	case DV_IFNET:
1210 		mountroot = nfs_mountroot;
1211 		nfsbootdevname = rootdv->dv_xname;
1212 		return;
1213 #endif
1214 	case DV_DISK:
1215 		mountroot = dk_mountroot;
1216 		part = DISKPART(rootdev);
1217 		break;
1218 	default:
1219 		printf("can't figure root, hope your kernel is right\n");
1220 		return;
1221 	}
1222 
1223 	printf("root on %s%c", rootdv->dv_xname, 'a' + part);
1224 
1225 	/*
1226 	 * Make the swap partition on the root drive the primary swap.
1227 	 */
1228 	for (swp = swdevt; swp->sw_dev != NODEV; swp++) {
1229 		if (major(rootdev) == major(swp->sw_dev) &&
1230 		    DISKUNIT(rootdev) == DISKUNIT(swp->sw_dev)) {
1231 			temp = swdevt[0].sw_dev;
1232 			swdevt[0].sw_dev = swp->sw_dev;
1233 			swp->sw_dev = temp;
1234 			break;
1235 		}
1236 	}
1237 	if (swp->sw_dev != NODEV) {
1238 		/*
1239 		 * If dumpdev was the same as the old primary swap device,
1240 		 * move it to the new primary swap device.
1241 		 */
1242 		if (temp == dumpdev)
1243 			dumpdev = swdevt[0].sw_dev;
1244 	}
1245 	if (swdevt[0].sw_dev != NODEV)
1246 		printf(" swap on %s%d%c", findblkname(major(swdevt[0].sw_dev)),
1247 		    DISKUNIT(swdevt[0].sw_dev),
1248 		    'a' + DISKPART(swdevt[0].sw_dev));
1249 	if (dumpdev != NODEV)
1250 		printf(" dump on %s%d%c", findblkname(major(dumpdev)),
1251 		    DISKUNIT(dumpdev), 'a' + DISKPART(dumpdev));
1252 	printf("\n");
1253 }
1254 
1255 extern struct nam2blk nam2blk[];
1256 
1257 int
1258 findblkmajor(struct device *dv)
1259 {
1260 	char buf[16], *p;
1261 	int i;
1262 
1263 	if (strlcpy(buf, dv->dv_xname, sizeof buf) >= sizeof buf)
1264 		return (-1);
1265 	for (p = buf; *p; p++)
1266 		if (*p >= '0' && *p <= '9')
1267 			*p = '\0';
1268 
1269 	for (i = 0; nam2blk[i].name; i++)
1270 		if (!strcmp(buf, nam2blk[i].name))
1271 			return (nam2blk[i].maj);
1272 	return (-1);
1273 }
1274 
1275 char *
1276 findblkname(int maj)
1277 {
1278 	int i;
1279 
1280 	for (i = 0; nam2blk[i].name; i++)
1281 		if (nam2blk[i].maj == maj)
1282 			return (nam2blk[i].name);
1283 	return (NULL);
1284 }
1285 
1286 int
1287 disk_map(char *path, char *mappath, int size, int flags)
1288 {
1289 	struct disk *dk, *mdk;
1290 	u_char uid[8];
1291 	char c, part;
1292 	int i;
1293 
1294 	/*
1295 	 * Attempt to map a request for a disklabel UID to the correct device.
1296 	 * We should be supplied with a disklabel UID which has the following
1297 	 * format:
1298 	 *
1299 	 * [disklabel uid] . [partition]
1300 	 *
1301 	 * Alternatively, if the DM_OPENPART flag is set the disklabel UID can
1302 	 * based passed on its own.
1303 	 */
1304 
1305 	if (strchr(path, '/') != NULL)
1306 		return -1;
1307 
1308 	/* Verify that the device name is properly formed. */
1309 	if (!((strlen(path) == 16 && (flags & DM_OPENPART)) ||
1310 	    (strlen(path) == 18 && path[16] == '.')))
1311 		return -1;
1312 
1313 	/* Get partition. */
1314 	if (flags & DM_OPENPART)
1315 		part = 'a' + RAW_PART;
1316 	else
1317 		part = path[17];
1318 
1319 	if (part < 'a' || part >= 'a' + MAXPARTITIONS)
1320 		return -1;
1321 
1322 	/* Derive label UID. */
1323 	bzero(uid, sizeof(uid));
1324 	for (i = 0; i < 16; i++) {
1325 		c = path[i];
1326 		if (c >= '0' && c <= '9')
1327 			c -= '0';
1328 		else if (c >= 'a' && c <= 'f')
1329 			c -= ('a' - 10);
1330                 else
1331 			return -1;
1332 
1333 		uid[i / 2] <<= 4;
1334 		uid[i / 2] |= c & 0xf;
1335 	}
1336 
1337 	mdk = NULL;
1338 	TAILQ_FOREACH(dk, &disklist, dk_link) {
1339 		if (dk->dk_label && bcmp(dk->dk_label->d_uid, uid,
1340 		    sizeof(dk->dk_label->d_uid)) == 0) {
1341 			/* Fail if there are duplicate UIDs! */
1342 			if (mdk != NULL)
1343 				return -1;
1344 			mdk = dk;
1345 		}
1346 	}
1347 
1348 	if (mdk == NULL || mdk->dk_name == NULL)
1349 		return -1;
1350 
1351 	snprintf(mappath, size, "/dev/%s%s%c",
1352 	    (flags & DM_OPENBLCK) ? "" : "r", mdk->dk_name, part);
1353 
1354 	return 0;
1355 }
1356