xref: /netbsd-src/sbin/fsck_lfs/setup.c (revision 3b01aba77a7a698587faaae455bbfe740923c1f5)
1 /* $NetBSD: setup.c,v 1.9 2001/07/13 20:30:19 perseant Exp $	 */
2 
3 /*
4  * Copyright (c) 1980, 1986, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. All advertising materials mentioning features or use of this software
16  *    must display the following acknowledgement:
17  *	This product includes software developed by the University of
18  *	California, Berkeley and its contributors.
19  * 4. Neither the name of the University nor the names of its contributors
20  *    may be used to endorse or promote products derived from this software
21  *    without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  */
35 
36 /* #define DKTYPENAMES */
37 #define FSTYPENAMES
38 #include <sys/param.h>
39 #include <sys/time.h>
40 #include <sys/stat.h>
41 #include <sys/ioctl.h>
42 #include <sys/disklabel.h>
43 #include <sys/file.h>
44 
45 #include <ufs/ufs/dinode.h>
46 #include <sys/mount.h>		/* XXX ufs/lfs/lfs.h should include this for
47 				 * us */
48 #include <ufs/lfs/lfs.h>
49 #include <ufs/lfs/lfs_extern.h>
50 
51 #include <ctype.h>
52 #include <err.h>
53 #include <errno.h>
54 #include <stdio.h>
55 #include <stdlib.h>
56 #include <string.h>
57 
58 #include "fsck.h"
59 #include "extern.h"
60 #include "fsutil.h"
61 
62 struct bufarea  asblk;
63 daddr_t        *din_table;
64 SEGUSE         *seg_table;
65 #define altsblock (*asblk.b_un.b_fs)
66 #define POWEROF2(num)	(((num) & ((num) - 1)) == 0)
67 
68 void            badsb(int, char *);
69 int             calcsb(const char *, int, struct lfs *);
70 static struct disklabel *getdisklabel(const char *, int);
71 static int      readsb(int);
72 int             lfs_maxino(void);
73 
74 static daddr_t  try_verify(struct lfs *, struct lfs *);
75 
76 #ifdef DKTYPENAMES
77 int             useless(void);
78 
79 int
80 useless(void)
81 {
82 	char          **foo = (char **)dktypenames;
83 	char          **bar = (char **)fscknames;
84 
85 	return foo - bar;
86 }
87 #endif
88 
89 static daddr_t
90 try_verify(struct lfs * osb, struct lfs * nsb)
91 {
92 	daddr_t         daddr;
93 	SEGSUM         *sp;
94 	char           *summary;
95 	int             bc, flag;
96 
97 	daddr = osb->lfs_offset;
98 	summary = malloc(osb->lfs_sumsize);
99 	while (daddr != nsb->lfs_offset) {
100 		flag = 0;
101 oncemore:
102 		/* Read in summary block */
103 		bread(fsreadfd, summary, fsbtodb(osb, daddr), osb->lfs_sumsize);
104 		sp = (SEGSUM *)summary;
105 
106 		/*
107 		 * Could be a superblock instead of a segment summary.
108 		 * XXX should use gseguse, but right now we need to do more
109 		 * setup before we can...fix this
110 		 */
111 		if (sp->ss_magic != SS_MAGIC ||
112 		  sp->ss_sumsum != cksum(&sp->ss_datasum, osb->lfs_sumsize -
113 					 sizeof(sp->ss_sumsum))) {
114 			if (flag == 0) {
115 				daddr += btofsb(osb, LFS_SBPAD);
116 				goto oncemore;
117 			}
118 			return 0x0;
119 		}
120 		bc = check_summary(osb, sp, daddr);
121 		if (bc == 0)
122 			break;
123 		daddr += btofsb(osb, osb->lfs_sumsize + bc);
124 		if (dtosn(osb, daddr) != dtosn(osb, daddr +
125 			btofsb(osb, osb->lfs_sumsize + osb->lfs_bsize)))
126 			daddr = ((SEGSUM *)summary)->ss_next;
127 	}
128 	return daddr;
129 }
130 
131 u_quad_t        maxtable[] = {
132 		/* 1 */ -1,
133 		/* 2 */ -1,
134 		/* 4 */ -1,
135 		/* 8 */ -1,
136 		/* 16 */ -1,
137 		/* 32 */ -1,
138 		/* 64 */ -1,
139 		/* 128 */ -1,
140 		/* 256 */ -1,
141 		/* 512 */ NDADDR + 128 + 128 * 128 + 128 * 128 * 128,
142 		/* 1024 */ NDADDR + 256 + 256 * 256 + 256 * 256 * 256,
143 		/* 2048 */ NDADDR + 512 + 512 * 512 + 512 * 512 * 512,
144 		/* 4096 */ NDADDR + 1024 + 1024 * 1024 + 1024 * 1024 * 1024,
145 		/* 8192 */ 1 << 31,
146 		/* 16 K */ 1 << 31,
147 		/* 32 K */ 1 << 31,
148 	};
149 
150 int
151 setup(const char *dev)
152 {
153 	long            bmapsize;
154 	struct disklabel *lp;
155 #if 0
156 	long            i;
157 	off_t           sizepb;
158 #endif
159 	struct stat     statb;
160 	daddr_t         daddr;
161 	struct lfs      proto;
162 	int             doskipclean;
163 	u_int64_t       maxfilesize;
164 	struct lfs     *sb0, *sb1, *osb, *nsb;
165 	struct dinode  *idinode;
166 
167 	havesb = 0;
168 	fswritefd = -1;
169 	doskipclean = skipclean;
170 	if (stat(dev, &statb) < 0) {
171 		printf("Can't stat %s: %s\n", dev, strerror(errno));
172 		return (0);
173 	}
174 	if (!S_ISCHR(statb.st_mode)) {
175 		pfatal("%s is not a character device", dev);
176 		if (reply("CONTINUE") == 0)
177 			return (0);
178 	}
179 	if ((fsreadfd = open(dev, O_RDONLY)) < 0) {
180 		printf("Can't open %s: %s\n", dev, strerror(errno));
181 		return (0);
182 	}
183 	if (preen == 0)
184 		printf("** %s", dev);
185 	if (nflag || (fswritefd = open(dev, O_WRONLY)) < 0) {
186 		fswritefd = -1;
187 		if (preen)
188 			pfatal("NO WRITE ACCESS");
189 		printf(" (NO WRITE)");
190 	}
191 	if (preen == 0)
192 		printf("\n");
193 	fsmodified = 0;
194 	lfdir = 0;
195 	initbarea(&sblk);
196 	initbarea(&asblk);
197 	sblk.b_un.b_buf = malloc(LFS_SBPAD);
198 	asblk.b_un.b_buf = malloc(LFS_SBPAD);
199 	if (sblk.b_un.b_buf == NULL || asblk.b_un.b_buf == NULL)
200 		errexit("cannot allocate space for superblock\n");
201 	if ((lp = getdisklabel((char *) NULL, fsreadfd)) != NULL)
202 		dev_bsize = secsize = lp->d_secsize;
203 	else
204 		dev_bsize = secsize = DEV_BSIZE;
205 
206 	/*
207 	 * Read in the superblock, looking for alternates if necessary
208 	 */
209 	if (readsb(1) == 0) {
210 		if (bflag || preen || calcsb(dev, fsreadfd, &proto) == 0)
211 			return (0);
212 		if (reply("LOOK FOR ALTERNATE SUPERBLOCKS") == 0)
213 			return (0);
214 #if 0				/* XXX find the LFS way to do this */
215 		for (cg = 0; cg < proto.lfs_ncg; cg++) {
216 			bflag = fsbtodb(&proto, cgsblock(&proto, cg));
217 			if (readsb(0) != 0)
218 				break;
219 		}
220 		if (cg >= proto.lfs_ncg) {
221 			printf("%s %s\n%s %s\n%s %s\n",
222 			       "SEARCH FOR ALTERNATE SUPER-BLOCK",
223 			       "FAILED. YOU MUST USE THE",
224 			       "-b OPTION TO FSCK_FFS TO SPECIFY THE",
225 			       "LOCATION OF AN ALTERNATE",
226 			       "SUPER-BLOCK TO SUPPLY NEEDED",
227 			       "INFORMATION; SEE fsck_ffs(8).");
228 			return (0);
229 		}
230 #else
231 		pwarn("XXX Can't look for alternate superblocks yet\n");
232 		return (0);
233 #endif
234 		doskipclean = 0;
235 		pwarn("USING ALTERNATE SUPERBLOCK AT %d\n", bflag);
236 	}
237 	bufinit();
238 
239 	if (bflag == 0x0 && idaddr == 0x0) {
240 		/*
241 		 * If we read a proper superblock, but its address was not
242 		 * lfs_sboffs[0], we're holding a fake primary superblock,
243 		 * and need to read the real one.
244 		 */
245 		if (sblock.lfs_sboffs[0] != dbtofsb(&sblock,
246 						    LFS_LABELPAD / dev_bsize))
247 		{
248 			if (debug)
249 				pwarn("Getting 'real' prinary superblock from 0x%x\n",
250 				      fsbtodb(&sblock, sblock.lfs_sboffs[0]));
251 			bflag = fsbtodb(&sblock, sblock.lfs_sboffs[0]);
252 			readsb(1);
253 			bflag = 0;
254 		}
255 
256 		/*
257 		 * Even if that superblock read in properly, it may not
258 		 * be guaranteed to point to a complete checkpoint.
259 		 * Read in the second superblock too, and take whichever
260 		 * of the two is *less* recent. --ks
261 		 */
262 		sb0 = malloc(sizeof(*sb0));
263 		sb1 = malloc(sizeof(*sb1));
264 		memcpy(sb0, &sblock, sizeof(*sb0));
265 		bflag = fsbtodb(&sblock, sblock.lfs_sboffs[1]);
266 		if (readsb(1) == 0) {
267 			pwarn("COULDN'T READ ALT SUPERBLOCK AT BLK %d", bflag);
268 			if (reply("ASSUME PRIMARY SUPERBLOCK IS GOOD") == 0) {
269 				return (0);
270 			} else {/* use primary as good */
271 				memcpy(&sblock, sb0, sizeof(*sb0));	/* XXX cheating? */
272 			}
273 		} else {
274 			memcpy(sb1, &sblock, sizeof(*sb1));
275 			if (debug) {
276 				if (sb0->lfs_version > 1) {
277 					pwarn("sb0 sn=%lld, sb1 sn=%lld\n",
278 					      (long long)sb0->lfs_serial,
279 					      (long long)sblock.lfs_serial);
280 				} else {
281 					pwarn("sb0 %lld, sb1 %lld\n",
282 					      (long long)sb0->lfs_otstamp,
283 					      (long long)sblock.lfs_otstamp);
284 				}
285 			}
286 			/*
287 			 * Verify the checkpoint of the newer superblock,
288 			 * if the timestamp of the two superblocks is
289 			 * different.  XXX use lfs_offset instead, discover
290 			 * how to quickly discover "newness" based on that.
291 			 */
292 			if ((sb0->lfs_version == 1 &&
293                              sb0->lfs_otstamp != sb1->lfs_otstamp) ||
294 			    (sb0->lfs_version > 1 &&
295                              sb0->lfs_serial != sb1->lfs_serial)) {
296 				if (sb0->lfs_version == 1) {
297 					if (sb0->lfs_otstamp > sb1->lfs_otstamp) {
298 						osb = sb1;
299 						nsb = sb0;
300 					} else {
301 						osb = sb0;
302 						nsb = sb1;
303 					}
304 				} else {
305 					if (sb0->lfs_serial > sb1->lfs_serial) {
306 						osb = sb1;
307 						nsb = sb0;
308 					} else {
309 						osb = sb0;
310 						nsb = sb1;
311 					}
312 				}
313 				daddr = try_verify(osb, nsb);
314 
315 				if (debug)
316 					printf("done.\n");
317 				if (daddr == nsb->lfs_offset) {
318 					pwarn("Checkpoint verified, recovered %lld seconds of data\n",
319 					      (long long)nsb->lfs_tstamp - (long long)osb->lfs_tstamp);
320 					memcpy(&sblock, nsb, sizeof(*nsb));
321 					sbdirty();
322 				} else {
323 					pwarn("Checkpoint invalid, lost %lld seconds of data\n", (long long)nsb->lfs_tstamp - (long long)osb->lfs_tstamp);
324 					memcpy(&sblock, osb, sizeof(*osb));
325 				}
326 			}
327 		}
328 		free(sb0);
329 		free(sb1);
330 	}
331 	if (idaddr == 0x0)
332 		idaddr = sblock.lfs_idaddr;
333 	if (debug) {
334 		printf("dev_bsize = %lu\n", dev_bsize);
335 		printf("lfs_bsize = %lu\n", (unsigned long)sblock.lfs_bsize);
336 		printf("lfs_fsize = %lu\n", (unsigned long)sblock.lfs_fsize);
337 		printf("lfs_frag  = %lu\n", (unsigned long)sblock.lfs_frag);
338 		printf("INOPB(fs) = %lu\n", (unsigned long)INOPB(&sblock));
339 		if (sblock.lfs_version > 1)
340 			printf("INOPF(fs) = %lu\n",
341 			       (unsigned long)INOPF(&sblock));
342 		/* printf("fsbtodb(fs,1) = %lu\n",fsbtodb(&sblock,1)); */
343 	}
344 	/* Compatibility */
345 	if (sblock.lfs_version == 1) {
346 		sblock.lfs_sumsize = LFS_V1_SUMMARY_SIZE;
347 		sblock.lfs_ibsize = sblock.lfs_bsize;
348 		sblock.lfs_start = sblock.lfs_sboffs[0];
349 		sblock.lfs_fsbtodb = 0;
350 	}
351 	initbarea(&iblk);
352 	iblk.b_un.b_buf = malloc(sblock.lfs_ibsize);
353 	if (bread(fsreadfd, (char *)iblk.b_un.b_buf, fsbtodb(&sblock, idaddr),
354 		  (long)sblock.lfs_ibsize) != 0) {
355 		printf("Couldn't read disk block %d\n", idaddr);
356 		exit(1);
357 	}
358 	idinode = lfs_difind(&sblock, sblock.lfs_ifile, &ifblock);
359 	if (idinode == NULL) {
360 		printf("Ifile inode not found at daddr 0x%x\n", idaddr);
361 		exit(1);
362 		/* XXX find it in the segment summaries */
363 	}
364 
365 	maxino = ((idinode->di_size
366 	    - (sblock.lfs_cleansz + sblock.lfs_segtabsz) * sblock.lfs_bsize)
367 		  / sblock.lfs_bsize) * sblock.lfs_ifpb;
368 	if (debug)
369 		printf("maxino    = %d\n", maxino);
370 	din_table = (daddr_t *)malloc(maxino * sizeof(*din_table));
371 	memset(din_table, 0, maxino * sizeof(*din_table));
372 	seg_table = (SEGUSE *)malloc(sblock.lfs_nseg * sizeof(SEGUSE));
373 	memset(seg_table, 0, sblock.lfs_nseg * sizeof(SEGUSE));
374 	if (sblock.lfs_version == 1)
375  		maxfsblock = sblock.lfs_size * (sblock.lfs_bsize / dev_bsize);
376  	else
377 		maxfsblock = sblock.lfs_size;
378 	maxfilesize = maxtable[sblock.lfs_bshift] << sblock.lfs_bshift;
379 	if ((sblock.lfs_minfree < 0 || sblock.lfs_minfree > 99)) {
380 		pfatal("IMPOSSIBLE MINFREE=%d IN SUPERBLOCK",
381 		       sblock.lfs_minfree);
382 		if (reply("SET TO DEFAULT") == 1) {
383 			sblock.lfs_minfree = 10;
384 			sbdirty();
385 		}
386 	}
387 	if (sblock.lfs_bmask != sblock.lfs_bsize - 1) {
388 		pwarn("INCORRECT BMASK=%x IN SUPERBLOCK (should be %x)",
389 		      (unsigned int)sblock.lfs_bmask,
390 		      (unsigned int)sblock.lfs_bsize - 1);
391 		sblock.lfs_bmask = sblock.lfs_bsize - 1;
392 		if (preen)
393 			printf(" (FIXED)\n");
394 		if (preen || reply("FIX") == 1) {
395 			sbdirty();
396 			dirty(&asblk);
397 		}
398 	}
399 #if 0				/* FFS-specific checks */
400 	if (sblock.lfs_fmask != ~(sblock.lfs_fsize - 1)) {
401 		pwarn("INCORRECT FMASK=%x IN SUPERBLOCK",
402 		      sblock.lfs_fmask);
403 		sblock.lfs_fmask = ~(sblock.lfs_fsize - 1);
404 		if (preen)
405 			printf(" (FIXED)\n");
406 		if (preen || reply("FIX") == 1) {
407 			sbdirty();
408 			dirty(&asblk);
409 		}
410 	}
411 #endif
412 	if (sblock.lfs_maxfilesize != maxfilesize) {
413 		pwarn(
414 		    "INCORRECT MAXFILESIZE=%llu IN SUPERBLOCK (should be %llu)",
415 		    (unsigned long long)sblock.lfs_maxfilesize,
416 		    (unsigned long long)maxfilesize);
417 		sblock.lfs_maxfilesize = maxfilesize;
418 		if (preen)
419 			printf(" (FIXED)\n");
420 		if (preen || reply("FIX") == 1) {
421 			sbdirty();
422 			dirty(&asblk);
423 		}
424 	}
425 	if (sblock.lfs_maxsymlinklen != MAXSYMLINKLEN) {
426 		pwarn("INCORRECT MAXSYMLINKLEN=%d IN SUPERBLOCK",
427 		      sblock.lfs_maxsymlinklen);
428 		sblock.lfs_maxsymlinklen = MAXSYMLINKLEN;
429 		if (preen)
430 			printf(" (FIXED)\n");
431 		if (preen || reply("FIX") == 1) {
432 			sbdirty();
433 			dirty(&asblk);
434 		}
435 	}
436 	newinofmt = 1;
437 	/*
438 	 * allocate and initialize the necessary maps
439 	 */
440 #ifndef VERBOSE_BLOCKMAP
441 	bmapsize = roundup(howmany(maxfsblock, NBBY), sizeof(int16_t));
442 	blockmap = calloc((unsigned)bmapsize, sizeof(char));
443 #else
444 	bmapsize = maxfsblock * sizeof(ino_t);
445 	blockmap = (ino_t *)calloc(maxfsblock, sizeof(ino_t));
446 #endif
447 	if (blockmap == NULL) {
448 		printf("cannot alloc %u bytes for blockmap\n",
449 		       (unsigned)bmapsize);
450 		goto badsblabel;
451 	}
452 
453 	statemap = calloc((unsigned)maxino, sizeof(char));
454 	if (statemap == NULL) {
455 		printf("cannot alloc %u bytes for statemap\n",
456 		       (unsigned)maxino);
457 		goto badsblabel;
458 	}
459 	typemap = calloc((unsigned)maxino, sizeof(char));
460 	if (typemap == NULL) {
461 		printf("cannot alloc %u bytes for typemap\n",
462 		       (unsigned)maxino);
463 		goto badsblabel;
464 	}
465 	lncntp = (int16_t *)calloc((unsigned)maxino, sizeof(int16_t));
466 	if (lncntp == NULL) {
467 		printf("cannot alloc %lu bytes for lncntp\n",
468 		       (unsigned long)maxino * sizeof(int16_t));
469 		goto badsblabel;
470 	}
471 	return (1);
472 
473 badsblabel:
474 	ckfini(0);
475 	return (0);
476 }
477 
478 /*
479  * Read in the LFS super block and its summary info.
480  */
481 static int
482 readsb(int listerr)
483 {
484 	daddr_t         super = bflag ? bflag : LFS_LABELPAD / dev_bsize;
485 	u_int32_t       checksum;
486 
487 	if (bread(fsreadfd, (char *) &sblock, super, (long) LFS_SBPAD) != 0)
488 		return (0);
489 
490 	sblk.b_bno = super;
491 	sblk.b_size = LFS_SBPAD;
492 	/*
493 	 * run a few consistency checks of the super block
494 	 */
495 	if (sblock.lfs_magic != LFS_MAGIC) {
496 		badsb(listerr, "MAGIC NUMBER WRONG");
497 		return (0);
498 	}
499 	/* checksum */
500 	checksum = lfs_sb_cksum(&(sblock.lfs_dlfs));
501 	if (sblock.lfs_cksum != checksum) {
502 		printf("Superblock checksum (%lu)does not match computed checksum %lu\n",
503 		(unsigned long)sblock.lfs_cksum, (unsigned long) checksum);
504 	}
505 #if 0				/* XXX - replace these checks with
506 				 * appropriate LFS sanity checks */
507 	if (sblock.lfs_ncg < 1) {
508 		badsb(listerr, "NCG OUT OF RANGE");
509 		return (0);
510 	}
511 	if (sblock.lfs_cpg < 1) {
512 		badsb(listerr, "CPG OUT OF RANGE");
513 		return (0);
514 	}
515 	if (sblock.lfs_ncg * sblock.lfs_cpg < sblock.lfs_ncyl ||
516 	    (sblock.lfs_ncg - 1) * sblock.lfs_cpg >= sblock.lfs_ncyl) {
517 		badsb(listerr, "NCYL LESS THAN NCG*CPG");
518 		return (0);
519 	}
520 	if (sblock.lfs_sbsize > SBSIZE) {
521 		badsb(listerr, "SIZE PREPOSTEROUSLY LARGE");
522 		return (0);
523 	}
524 #endif
525 	/*
526 	 * Compute block size that the filesystem is based on,
527 	 * according to fsbtodb, and adjust superblock block number
528 	 * so we can tell if this is an alternate later.
529 	 */
530 	super *= dev_bsize;
531 #if 0
532 	dev_bsize = sblock.lfs_bsize / fsbtodb(&sblock, 1);
533 #endif
534 	sblk.b_bno = super / dev_bsize;
535 	if (bflag) {
536 		havesb = 1;
537 		return (1);
538 	}
539 #if 0				/* XXX - for now skip the alt. superblock
540 				 * test as well */
541 	/*
542 	 * Set all possible fields that could differ, then do check
543 	 * of whole super block against an alternate super block.
544 	 * When an alternate super-block is specified this check is skipped.
545 	 */
546 	getblk(&asblk, cgsblock(&sblock, sblock.lfs_ncg - 1), sblock.lfs_sbsize);
547 	if (asblk.b_errs)
548 		return (0);
549 	altsblock.lfs_firstfield = sblock.lfs_firstfield;
550 	altsblock.lfs_fscktime = sblock.lfs_fscktime;
551 	altsblock.lfs_time = sblock.lfs_time;
552 	altsblock.lfs_cstotal = sblock.lfs_cstotal;
553 	altsblock.lfs_cgrotor = sblock.lfs_cgrotor;
554 	altsblock.lfs_fmod = sblock.lfs_fmod;
555 	altsblock.lfs_clean = sblock.lfs_clean;
556 	altsblock.lfs_ronly = sblock.lfs_ronly;
557 	altsblock.lfs_flags = sblock.lfs_flags;
558 	altsblock.lfs_maxcontig = sblock.lfs_maxcontig;
559 	altsblock.lfs_minfree = sblock.lfs_minfree;
560 	altsblock.lfs_optim = sblock.lfs_optim;
561 	altsblock.lfs_rotdelay = sblock.lfs_rotdelay;
562 	altsblock.lfs_maxbpg = sblock.lfs_maxbpg;
563 	memcpy(altsblock.lfs_csp, sblock.lfs_csp,
564 	       sizeof sblock.lfs_csp);
565 	altsblock.lfs_maxcluster = sblock.lfs_maxcluster;
566 	memcpy(altsblock.lfs_fsmnt, sblock.lfs_fsmnt,
567 	       sizeof sblock.lfs_fsmnt);
568 	memcpy(altsblock.lfs_sparecon, sblock.lfs_sparecon,
569 	       sizeof sblock.lfs_sparecon);
570 	/*
571 	 * The following should not have to be copied.
572 	 */
573 	altsblock.lfs_fsbtodb = sblock.lfs_fsbtodb;
574 	altsblock.lfs_interleave = sblock.lfs_interleave;
575 	altsblock.lfs_npsect = sblock.lfs_npsect;
576 	altsblock.lfs_nrpos = sblock.lfs_nrpos;
577 	altsblock.lfs_state = sblock.lfs_state;
578 	altsblock.lfs_qbmask = sblock.lfs_qbmask;
579 	altsblock.lfs_qfmask = sblock.lfs_qfmask;
580 	altsblock.lfs_state = sblock.lfs_state;
581 	altsblock.lfs_maxfilesize = sblock.lfs_maxfilesize;
582 	if (memcmp(&sblock, &altsblock, (int)sblock.lfs_sbsize)) {
583 		if (debug) {
584 			long           *nlp, *olp, *endlp;
585 
586 			printf("superblock mismatches\n");
587 			nlp = (long *) &altsblock;
588 			olp = (long *) &sblock;
589 			endlp = olp + (sblock.lfs_sbsize / sizeof *olp);
590 			for (; olp < endlp; olp++, nlp++) {
591 				if (*olp == *nlp)
592 					continue;
593 				printf("offset %d, original %ld, alternate %ld\n",
594 				       olp - (long *) &sblock, *olp, *nlp);
595 			}
596 		}
597 		badsb(listerr,
598 		      "VALUES IN SUPER BLOCK DISAGREE WITH THOSE IN FIRST ALTERNATE");
599 		return (0);
600 	}
601 #endif
602 	havesb = 1;
603 	return (1);
604 }
605 
606 void
607 badsb(int listerr, char *s)
608 {
609 
610 	if (!listerr)
611 		return;
612 	if (preen)
613 		printf("%s: ", cdevname());
614 	pfatal("BAD SUPER BLOCK: %s\n", s);
615 }
616 
617 /*
618  * Calculate a prototype superblock based on information in the disk label.
619  * When done the cgsblock macro can be calculated and the fs_ncg field
620  * can be used. Do NOT attempt to use other macros without verifying that
621  * their needed information is available!
622  */
623 int
624 calcsb(const char *dev, int devfd, struct lfs * fs)
625 {
626 	register struct disklabel *lp;
627 	register struct partition *pp;
628 	register char  *cp;
629 	int             i;
630 
631 	cp = strchr(dev, '\0') - 1;
632 	if ((cp == (char *) -1 || (*cp < 'a' || *cp > 'h')) && !isdigit(*cp)) {
633 		pfatal("%s: CANNOT FIGURE OUT FILE SYSTEM PARTITION\n", dev);
634 		return (0);
635 	}
636 	lp = getdisklabel(dev, devfd);
637 	if (lp == NULL) {
638 		dev_bsize = DEV_BSIZE;
639 	} else {
640 		if (isdigit(*cp))
641 			pp = &lp->d_partitions[0];
642 		else
643 			pp = &lp->d_partitions[*cp - 'a'];
644 		if (pp->p_fstype != FS_BSDLFS) {
645 			pfatal("%s: NOT LABELED AS AN LFS FILE SYSTEM (%s)\n",
646 			       dev, pp->p_fstype < FSMAXTYPES ?
647 			       fstypenames[pp->p_fstype] : "unknown");
648 			return (0);
649 		}
650 		memset(fs, 0, sizeof(struct lfs));
651 		fs->lfs_fsize = pp->p_fsize;
652 		fs->lfs_frag = pp->p_frag;
653 		fs->lfs_size = pp->p_size;
654 		fs->lfs_nspf = fs->lfs_fsize / lp->d_secsize;
655 		dev_bsize = lp->d_secsize;
656 		for (fs->lfs_fsbtodb = 0, i = fs->lfs_nspf; i > 1; i >>= 1)
657 			fs->lfs_fsbtodb++;
658 	}
659 	return (1);
660 }
661 
662 static struct disklabel *
663 getdisklabel(const char *s, int fd)
664 {
665 	static struct disklabel lab;
666 
667 	if (ioctl(fd, DIOCGDINFO, (char *) &lab) < 0) {
668 		if (s == NULL)
669 			return ((struct disklabel *) NULL);
670 		pwarn("ioctl (GCINFO): %s\n", strerror(errno));
671 #if 0
672 		errexit("%s: can't read disk label\n", s);
673 #else
674 		return NULL;
675 #endif
676 	}
677 	return (&lab);
678 }
679