xref: /netbsd-src/sbin/fsck_lfs/setup.c (revision bcc8ec9959e7b01e313d813067bfb43a3ad70551)
1 /* $NetBSD: setup.c,v 1.8 2001/01/05 02:02:58 lukem 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[LFS_SUMMARY_SIZE];
95 	int             bc, flag;
96 
97 	daddr = osb->lfs_offset;
98 	while (daddr != nsb->lfs_offset) {
99 		flag = 0;
100 oncemore:
101 		/* Read in summary block */
102 		bread(fsreadfd, summary, daddr, LFS_SUMMARY_SIZE);
103 		sp = (SEGSUM *)summary;
104 
105 		/*
106 		 * Could be a superblock instead of a segment summary.
107 		 * XXX should use gseguse, but right now we need to do more
108 		 * setup before we can...fix this
109 		 */
110 		if (sp->ss_magic != SS_MAGIC ||
111 		  sp->ss_sumsum != cksum(&sp->ss_datasum, LFS_SUMMARY_SIZE -
112 					 sizeof(sp->ss_sumsum))) {
113 			if (flag == 0) {
114 				daddr += LFS_SBPAD / dev_bsize;
115 				goto oncemore;
116 			}
117 			return 0x0;
118 		}
119 		bc = check_summary(osb, sp, daddr);
120 		if (bc == 0)
121 			break;
122 		daddr += (LFS_SUMMARY_SIZE + bc) / dev_bsize;
123 		if (datosn(osb, daddr) != datosn(osb, daddr + (LFS_SUMMARY_SIZE + (1 << osb->lfs_bshift)) / dev_bsize)) {
124 			daddr = ((SEGSUM *)summary)->ss_next;
125 		}
126 	}
127 	return daddr;
128 }
129 
130 int
131 setup(const char *dev)
132 {
133 	long            bmapsize;
134 	struct disklabel *lp;
135 #if 0
136 	long            i;
137 	off_t           sizepb;
138 #endif
139 	struct stat     statb;
140 	daddr_t         daddr;
141 	struct lfs      proto;
142 	int             doskipclean;
143 	u_int64_t       maxfilesize;
144 	struct lfs     *sb0, *sb1, *osb, *nsb;
145 	struct dinode  *idinode;
146 
147 	havesb = 0;
148 	fswritefd = -1;
149 	doskipclean = skipclean;
150 	if (stat(dev, &statb) < 0) {
151 		printf("Can't stat %s: %s\n", dev, strerror(errno));
152 		return (0);
153 	}
154 	if (!S_ISCHR(statb.st_mode)) {
155 		pfatal("%s is not a character device", dev);
156 		if (reply("CONTINUE") == 0)
157 			return (0);
158 	}
159 	if ((fsreadfd = open(dev, O_RDONLY)) < 0) {
160 		printf("Can't open %s: %s\n", dev, strerror(errno));
161 		return (0);
162 	}
163 	if (preen == 0)
164 		printf("** %s", dev);
165 	if (nflag || (fswritefd = open(dev, O_WRONLY)) < 0) {
166 		fswritefd = -1;
167 		if (preen)
168 			pfatal("NO WRITE ACCESS");
169 		printf(" (NO WRITE)");
170 	}
171 	if (preen == 0)
172 		printf("\n");
173 	fsmodified = 0;
174 	lfdir = 0;
175 	initbarea(&sblk);
176 	initbarea(&asblk);
177 	sblk.b_un.b_buf = malloc(LFS_SBPAD);
178 	asblk.b_un.b_buf = malloc(LFS_SBPAD);
179 	if (sblk.b_un.b_buf == NULL || asblk.b_un.b_buf == NULL)
180 		errexit("cannot allocate space for superblock\n");
181 	if ((lp = getdisklabel((char *) NULL, fsreadfd)) != NULL)
182 		dev_bsize = secsize = lp->d_secsize;
183 	else
184 		dev_bsize = secsize = DEV_BSIZE;
185 
186 	/*
187 	 * Read in the superblock, looking for alternates if necessary
188 	 */
189 	if (readsb(1) == 0) {
190 		if (bflag || preen || calcsb(dev, fsreadfd, &proto) == 0)
191 			return (0);
192 		if (reply("LOOK FOR ALTERNATE SUPERBLOCKS") == 0)
193 			return (0);
194 #if 0				/* XXX find the LFS way to do this */
195 		for (cg = 0; cg < proto.lfs_ncg; cg++) {
196 			bflag = fsbtodb(&proto, cgsblock(&proto, cg));
197 			if (readsb(0) != 0)
198 				break;
199 		}
200 		if (cg >= proto.lfs_ncg) {
201 			printf("%s %s\n%s %s\n%s %s\n",
202 			       "SEARCH FOR ALTERNATE SUPER-BLOCK",
203 			       "FAILED. YOU MUST USE THE",
204 			       "-b OPTION TO FSCK_FFS TO SPECIFY THE",
205 			       "LOCATION OF AN ALTERNATE",
206 			       "SUPER-BLOCK TO SUPPLY NEEDED",
207 			       "INFORMATION; SEE fsck_ffs(8).");
208 			return (0);
209 		}
210 #else
211 		pwarn("XXX Can't look for alternate superblocks yet\n");
212 		return (0);
213 #endif
214 		doskipclean = 0;
215 		pwarn("USING ALTERNATE SUPERBLOCK AT %d\n", bflag);
216 	}
217 	bufinit();
218 
219 	if (bflag == 0x0 && idaddr == 0x0) {
220 		/*
221 		 * Even if that superblock read in properly, it may not
222 		 * be guaranteed to point to a complete checkpoint.
223 		 * Read in the second superblock too, and take whichever
224 		 * of the two is *less* recent. --ks
225 		 */
226 		sb0 = malloc(sizeof(*sb0));
227 		sb1 = malloc(sizeof(*sb1));
228 		memcpy(sb0, &sblock, sizeof(*sb0));
229 		bflag = sblock.lfs_sboffs[1];
230 		if (readsb(1) == 0) {
231 			pwarn("COULDN'T READ ALT SUPERBLOCK AT BLK %d", bflag);
232 			if (reply("ASSUME PRIMARY SUPERBLOCK IS GOOD") == 0) {
233 				return (0);
234 			} else {/* use primary as good */
235 				memcpy(&sblock, sb0, sizeof(*sb0));	/* XXX cheating? */
236 			}
237 		} else {
238 			memcpy(sb1, &sblock, sizeof(*sb1));
239 			if (debug)
240 				pwarn("sb0 %d, sb1 %d\n", sb0->lfs_tstamp, sblock.lfs_tstamp);
241 			/*
242 			 * Verify the checkpoint of the newer superblock,
243 			 * if the timestamp of the two superblocks is
244 			 * different.  XXX use lfs_offset instead, discover
245 			 * how to quickly discover "newness" based on that.
246 			 */
247 			if (sb0->lfs_tstamp != sb1->lfs_tstamp) {
248 				if (sb0->lfs_tstamp > sb1->lfs_tstamp) {
249 					osb = sb1;
250 					nsb = sb0;
251 				} else {
252 					osb = sb0;
253 					nsb = sb1;
254 				}
255 				daddr = try_verify(osb, nsb);
256 
257 				if (debug)
258 					printf("done.\n");
259 				if (daddr == nsb->lfs_offset) {
260 					pwarn("Checkpoint verified, recovered %d seconds of data\n", nsb->lfs_tstamp - osb->lfs_tstamp);
261 					memcpy(&sblock, nsb, sizeof(*nsb));
262 					sbdirty();
263 				} else {
264 					pwarn("Checkpoint invalid, lost %d seconds of data\n", nsb->lfs_tstamp - osb->lfs_tstamp);
265 					memcpy(&sblock, osb, sizeof(*osb));
266 				}
267 			}
268 		}
269 		free(sb0);
270 		free(sb1);
271 	}
272 	if (idaddr == 0x0)
273 		idaddr = sblock.lfs_idaddr;
274 	if (debug) {
275 		printf("dev_bsize = %lu\n", dev_bsize);
276 		printf("lfs_bsize = %lu\n", (unsigned long)sblock.lfs_bsize);
277 		printf("lfs_fsize = %lu\n", (unsigned long)sblock.lfs_fsize);
278 		printf("lfs_frag  = %lu\n", (unsigned long)sblock.lfs_frag);
279 		printf("INOPB(fs) = %lu\n", (unsigned long) INOPB(&sblock));
280 		/* printf("fsbtodb(fs,1) = %lu\n",fsbtodb(&sblock,1)); */
281 	}
282 #if 0				/* FFS-specific fs-clean check */
283 	if (debug)
284 		printf("clean = %d\n", sblock.lfs_clean);
285 	if (sblock.lfs_clean & FS_ISCLEAN) {
286 		if (doskipclean) {
287 			pwarn("%sile system is clean; not checking\n",
288 			      preen ? "f" : "** F");
289 			return (-1);
290 		}
291 		if (!preen)
292 			pwarn("** File system is already clean\n");
293 	}
294 	maxino = sblock.lfs_ncg * sblock.lfs_ipg;
295 #else
296 	initbarea(&iblk);
297 	iblk.b_un.b_buf = malloc(sblock.lfs_bsize);
298 	if (bread(fsreadfd, (char *)iblk.b_un.b_buf, idaddr,
299 		  (long)sblock.lfs_bsize) != 0) {
300 		printf("Couldn't read disk block %d\n", idaddr);
301 		exit(1);
302 	}
303 	idinode = lfs_difind(&sblock, sblock.lfs_ifile, &ifblock);
304 	maxino = ((idinode->di_size
305 	    - (sblock.lfs_cleansz + sblock.lfs_segtabsz) * sblock.lfs_bsize)
306 		  / sblock.lfs_bsize) * sblock.lfs_ifpb;
307 	if (debug)
308 		printf("maxino=%d\n", maxino);
309 	din_table = (daddr_t *)malloc(maxino * sizeof(*din_table));
310 	memset(din_table, 0, maxino * sizeof(*din_table));
311 	seg_table = (SEGUSE *)malloc(sblock.lfs_nseg * sizeof(SEGUSE));
312 	memset(seg_table, 0, sblock.lfs_nseg * sizeof(SEGUSE));
313 #endif
314 	maxfsblock = sblock.lfs_size * (sblock.lfs_bsize / dev_bsize);
315 #if 0
316 	sizepb = sblock.lfs_bsize;
317 	maxfilesize = sblock.lfs_bsize * NDADDR - 1;
318 	for (i = 0; i < NIADDR; i++) {
319 		sizepb *= NINDIR(&sblock);
320 		maxfilesize += sizepb;
321 	}
322 	maxfilesize++;		/* XXX */
323 #else				/* LFS way */
324 	{
325 		u_quad_t        maxtable[] = {
326 			 /* 1 */ -1,
327 			 /* 2 */ -1,
328 			 /* 4 */ -1,
329 			 /* 8 */ -1,
330 			 /* 16 */ -1,
331 			 /* 32 */ -1,
332 			 /* 64 */ -1,
333 			 /* 128 */ -1,
334 			 /* 256 */ -1,
335 			 /* 512 */ NDADDR + 128 + 128 * 128 + 128 * 128 * 128,
336 			 /* 1024 */ NDADDR + 256 + 256 * 256 + 256 * 256 * 256,
337 			 /* 2048 */ NDADDR + 512 + 512 * 512 + 512 * 512 * 512,
338 			 /* 4096 */ NDADDR + 1024 + 1024 * 1024 + 1024 * 1024 * 1024,
339 			 /* 8192 */ 1 << 31,
340 			 /* 16 K */ 1 << 31,
341 			 /* 32 K */ 1 << 31,
342 		};
343 		maxfilesize = maxtable[sblock.lfs_bshift] << sblock.lfs_bshift;
344 	}
345 #endif
346 	if ((sblock.lfs_minfree < 0 || sblock.lfs_minfree > 99)) {
347 		pfatal("IMPOSSIBLE MINFREE=%d IN SUPERBLOCK",
348 		       sblock.lfs_minfree);
349 		if (reply("SET TO DEFAULT") == 1) {
350 			sblock.lfs_minfree = 10;
351 			sbdirty();
352 		}
353 	}
354 	/* XXX used to be ~(sblock.lfs_bsize - 1) */
355 	if (sblock.lfs_bmask != sblock.lfs_bsize - 1) {
356 		pwarn("INCORRECT BMASK=%x IN SUPERBLOCK (should be %x)",
357 		      (unsigned int)sblock.lfs_bmask,
358 		      (unsigned int)sblock.lfs_bsize - 1);
359 		sblock.lfs_bmask = sblock.lfs_bsize - 1;
360 		if (preen)
361 			printf(" (FIXED)\n");
362 		if (preen || reply("FIX") == 1) {
363 			sbdirty();
364 			dirty(&asblk);
365 		}
366 	}
367 #if 0				/* FFS-specific checks */
368 	if (sblock.lfs_fmask != ~(sblock.lfs_fsize - 1)) {
369 		pwarn("INCORRECT FMASK=%x IN SUPERBLOCK",
370 		      sblock.lfs_fmask);
371 		sblock.lfs_fmask = ~(sblock.lfs_fsize - 1);
372 		if (preen)
373 			printf(" (FIXED)\n");
374 		if (preen || reply("FIX") == 1) {
375 			sbdirty();
376 			dirty(&asblk);
377 		}
378 	}
379 #endif
380 	if (sblock.lfs_maxfilesize != maxfilesize) {
381 		pwarn(
382 		    "INCORRECT MAXFILESIZE=%llu IN SUPERBLOCK (should be %llu)",
383 		    (unsigned long long)sblock.lfs_maxfilesize,
384 		    (unsigned long long)maxfilesize);
385 		sblock.lfs_maxfilesize = maxfilesize;
386 		if (preen)
387 			printf(" (FIXED)\n");
388 		if (preen || reply("FIX") == 1) {
389 			sbdirty();
390 			dirty(&asblk);
391 		}
392 	}
393 	if (sblock.lfs_maxsymlinklen != MAXSYMLINKLEN) {
394 		pwarn("INCORRECT MAXSYMLINKLEN=%d IN SUPERBLOCK",
395 		      sblock.lfs_maxsymlinklen);
396 		sblock.lfs_maxsymlinklen = MAXSYMLINKLEN;
397 		if (preen)
398 			printf(" (FIXED)\n");
399 		if (preen || reply("FIX") == 1) {
400 			sbdirty();
401 			dirty(&asblk);
402 		}
403 	}
404 	newinofmt = 1;
405 	/*
406 	 * allocate and initialize the necessary maps
407 	 */
408 #ifndef VERBOSE_BLOCKMAP
409 	bmapsize = roundup(howmany(maxfsblock, NBBY), sizeof(int16_t));
410 	blockmap = calloc((unsigned)bmapsize, sizeof(char));
411 #else
412 	bmapsize = maxfsblock * sizeof(ino_t);
413 	blockmap = (ino_t *)calloc(maxfsblock, sizeof(ino_t));
414 #endif
415 	if (blockmap == NULL) {
416 		printf("cannot alloc %u bytes for blockmap\n",
417 		       (unsigned)bmapsize);
418 		goto badsblabel;
419 	}
420 
421 	statemap = calloc((unsigned)maxino, sizeof(char));
422 	if (statemap == NULL) {
423 		printf("cannot alloc %u bytes for statemap\n",
424 		       (unsigned)maxino);
425 		goto badsblabel;
426 	}
427 	typemap = calloc((unsigned)maxino, sizeof(char));
428 	if (typemap == NULL) {
429 		printf("cannot alloc %u bytes for typemap\n",
430 		       (unsigned)maxino);
431 		goto badsblabel;
432 	}
433 	lncntp = (int16_t *)calloc((unsigned)maxino, sizeof(int16_t));
434 	if (lncntp == NULL) {
435 		printf("cannot alloc %lu bytes for lncntp\n",
436 		       (unsigned long)maxino * sizeof(int16_t));
437 		goto badsblabel;
438 	}
439 	return (1);
440 
441 badsblabel:
442 	ckfini(0);
443 	return (0);
444 }
445 
446 /*
447  * Read in the LFS super block and its summary info.
448  */
449 static int
450 readsb(int listerr)
451 {
452 	daddr_t         super = bflag ? bflag : LFS_LABELPAD / dev_bsize;
453 	u_int32_t       checksum;
454 
455 	if (bread(fsreadfd, (char *) &sblock, super, (long) LFS_SBPAD) != 0)
456 		return (0);
457 
458 	sblk.b_bno = super;
459 	sblk.b_size = LFS_SBPAD;
460 	/*
461 	 * run a few consistency checks of the super block
462 	 */
463 	if (sblock.lfs_magic != LFS_MAGIC) {
464 		badsb(listerr, "MAGIC NUMBER WRONG");
465 		return (0);
466 	}
467 	/* checksum */
468 	checksum = lfs_sb_cksum(&(sblock.lfs_dlfs));
469 	if (sblock.lfs_cksum != checksum) {
470 		printf("Superblock checksum (%lu)does not match computed checksum %lu\n",
471 		(unsigned long)sblock.lfs_cksum, (unsigned long) checksum);
472 	}
473 #if 0				/* XXX - replace these checks with
474 				 * appropriate LFS sanity checks */
475 	if (sblock.lfs_ncg < 1) {
476 		badsb(listerr, "NCG OUT OF RANGE");
477 		return (0);
478 	}
479 	if (sblock.lfs_cpg < 1) {
480 		badsb(listerr, "CPG OUT OF RANGE");
481 		return (0);
482 	}
483 	if (sblock.lfs_ncg * sblock.lfs_cpg < sblock.lfs_ncyl ||
484 	    (sblock.lfs_ncg - 1) * sblock.lfs_cpg >= sblock.lfs_ncyl) {
485 		badsb(listerr, "NCYL LESS THAN NCG*CPG");
486 		return (0);
487 	}
488 	if (sblock.lfs_sbsize > SBSIZE) {
489 		badsb(listerr, "SIZE PREPOSTEROUSLY LARGE");
490 		return (0);
491 	}
492 #endif
493 	/*
494 	 * Compute block size that the filesystem is based on,
495 	 * according to fsbtodb, and adjust superblock block number
496 	 * so we can tell if this is an alternate later.
497 	 */
498 	super *= dev_bsize;
499 #if 0
500 	dev_bsize = sblock.lfs_bsize / fsbtodb(&sblock, 1);
501 #endif
502 	sblk.b_bno = super / dev_bsize;
503 	if (bflag) {
504 		havesb = 1;
505 		return (1);
506 	}
507 #if 0				/* XXX - for now skip the alt. superblock
508 				 * test as well */
509 	/*
510 	 * Set all possible fields that could differ, then do check
511 	 * of whole super block against an alternate super block.
512 	 * When an alternate super-block is specified this check is skipped.
513 	 */
514 	getblk(&asblk, cgsblock(&sblock, sblock.lfs_ncg - 1), sblock.lfs_sbsize);
515 	if (asblk.b_errs)
516 		return (0);
517 	altsblock.lfs_firstfield = sblock.lfs_firstfield;
518 	altsblock.lfs_fscktime = sblock.lfs_fscktime;
519 	altsblock.lfs_time = sblock.lfs_time;
520 	altsblock.lfs_cstotal = sblock.lfs_cstotal;
521 	altsblock.lfs_cgrotor = sblock.lfs_cgrotor;
522 	altsblock.lfs_fmod = sblock.lfs_fmod;
523 	altsblock.lfs_clean = sblock.lfs_clean;
524 	altsblock.lfs_ronly = sblock.lfs_ronly;
525 	altsblock.lfs_flags = sblock.lfs_flags;
526 	altsblock.lfs_maxcontig = sblock.lfs_maxcontig;
527 	altsblock.lfs_minfree = sblock.lfs_minfree;
528 	altsblock.lfs_optim = sblock.lfs_optim;
529 	altsblock.lfs_rotdelay = sblock.lfs_rotdelay;
530 	altsblock.lfs_maxbpg = sblock.lfs_maxbpg;
531 	memcpy(altsblock.lfs_csp, sblock.lfs_csp,
532 	       sizeof sblock.lfs_csp);
533 	altsblock.lfs_maxcluster = sblock.lfs_maxcluster;
534 	memcpy(altsblock.lfs_fsmnt, sblock.lfs_fsmnt,
535 	       sizeof sblock.lfs_fsmnt);
536 	memcpy(altsblock.lfs_sparecon, sblock.lfs_sparecon,
537 	       sizeof sblock.lfs_sparecon);
538 	/*
539 	 * The following should not have to be copied.
540 	 */
541 	altsblock.lfs_fsbtodb = sblock.lfs_fsbtodb;
542 	altsblock.lfs_interleave = sblock.lfs_interleave;
543 	altsblock.lfs_npsect = sblock.lfs_npsect;
544 	altsblock.lfs_nrpos = sblock.lfs_nrpos;
545 	altsblock.lfs_state = sblock.lfs_state;
546 	altsblock.lfs_qbmask = sblock.lfs_qbmask;
547 	altsblock.lfs_qfmask = sblock.lfs_qfmask;
548 	altsblock.lfs_state = sblock.lfs_state;
549 	altsblock.lfs_maxfilesize = sblock.lfs_maxfilesize;
550 	if (memcmp(&sblock, &altsblock, (int)sblock.lfs_sbsize)) {
551 		if (debug) {
552 			long           *nlp, *olp, *endlp;
553 
554 			printf("superblock mismatches\n");
555 			nlp = (long *) &altsblock;
556 			olp = (long *) &sblock;
557 			endlp = olp + (sblock.lfs_sbsize / sizeof *olp);
558 			for (; olp < endlp; olp++, nlp++) {
559 				if (*olp == *nlp)
560 					continue;
561 				printf("offset %d, original %ld, alternate %ld\n",
562 				       olp - (long *) &sblock, *olp, *nlp);
563 			}
564 		}
565 		badsb(listerr,
566 		      "VALUES IN SUPER BLOCK DISAGREE WITH THOSE IN FIRST ALTERNATE");
567 		return (0);
568 	}
569 #endif
570 	havesb = 1;
571 	return (1);
572 }
573 
574 void
575 badsb(int listerr, char *s)
576 {
577 
578 	if (!listerr)
579 		return;
580 	if (preen)
581 		printf("%s: ", cdevname());
582 	pfatal("BAD SUPER BLOCK: %s\n", s);
583 }
584 
585 /*
586  * Calculate a prototype superblock based on information in the disk label.
587  * When done the cgsblock macro can be calculated and the fs_ncg field
588  * can be used. Do NOT attempt to use other macros without verifying that
589  * their needed information is available!
590  */
591 int
592 calcsb(const char *dev, int devfd, struct lfs * fs)
593 {
594 	register struct disklabel *lp;
595 	register struct partition *pp;
596 	register char  *cp;
597 	int             i;
598 
599 	cp = strchr(dev, '\0') - 1;
600 	if ((cp == (char *) -1 || (*cp < 'a' || *cp > 'h')) && !isdigit(*cp)) {
601 		pfatal("%s: CANNOT FIGURE OUT FILE SYSTEM PARTITION\n", dev);
602 		return (0);
603 	}
604 	lp = getdisklabel(dev, devfd);
605 	if (lp == NULL) {
606 		dev_bsize = DEV_BSIZE;
607 	} else {
608 		if (isdigit(*cp))
609 			pp = &lp->d_partitions[0];
610 		else
611 			pp = &lp->d_partitions[*cp - 'a'];
612 		if (pp->p_fstype != FS_BSDLFS) {
613 			pfatal("%s: NOT LABELED AS AN LFS FILE SYSTEM (%s)\n",
614 			       dev, pp->p_fstype < FSMAXTYPES ?
615 			       fstypenames[pp->p_fstype] : "unknown");
616 			return (0);
617 		}
618 		memset(fs, 0, sizeof(struct lfs));
619 		fs->lfs_fsize = pp->p_fsize;
620 		fs->lfs_frag = pp->p_frag;
621 		fs->lfs_size = pp->p_size;
622 		fs->lfs_nspf = fs->lfs_fsize / lp->d_secsize;
623 		dev_bsize = lp->d_secsize;
624 		for (fs->lfs_fsbtodb = 0, i = fs->lfs_nspf; i > 1; i >>= 1)
625 			fs->lfs_fsbtodb++;
626 	}
627 	return (1);
628 }
629 
630 static struct disklabel *
631 getdisklabel(const char *s, int fd)
632 {
633 	static struct disklabel lab;
634 
635 	if (ioctl(fd, DIOCGDINFO, (char *) &lab) < 0) {
636 		if (s == NULL)
637 			return ((struct disklabel *) NULL);
638 		pwarn("ioctl (GCINFO): %s\n", strerror(errno));
639 #if 0
640 		errexit("%s: can't read disk label\n", s);
641 #else
642 		return NULL;
643 #endif
644 	}
645 	return (&lab);
646 }
647