xref: /netbsd-src/sbin/fsck_ffs/setup.c (revision 27578b9aac214cc7796ead81dcc5427e79d5f2a0)
1 /*	$NetBSD: setup.c,v 1.50 2001/09/18 08:38:28 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 #include <sys/cdefs.h>
37 #ifndef lint
38 #if 0
39 static char sccsid[] = "@(#)setup.c	8.10 (Berkeley) 5/9/95";
40 #else
41 __RCSID("$NetBSD: setup.c,v 1.50 2001/09/18 08:38:28 lukem Exp $");
42 #endif
43 #endif /* not lint */
44 
45 #include <sys/param.h>
46 #include <sys/time.h>
47 #include <sys/stat.h>
48 #include <sys/ioctl.h>
49 #define FSTYPENAMES
50 #include <sys/disklabel.h>
51 #include <sys/file.h>
52 
53 #include <ufs/ufs/dinode.h>
54 #include <ufs/ufs/ufs_bswap.h>
55 #include <ufs/ffs/fs.h>
56 #include <ufs/ffs/ffs_extern.h>
57 
58 #include <ctype.h>
59 #include <err.h>
60 #include <errno.h>
61 #include <stdio.h>
62 #include <stdlib.h>
63 #include <string.h>
64 
65 #include "fsck.h"
66 #include "extern.h"
67 #include "fsutil.h"
68 
69 #define POWEROF2(num)	(((num) & ((num) - 1)) == 0)
70 
71 static void badsb __P((int, char *));
72 static int calcsb __P((const char *, int, struct fs *));
73 static struct disklabel *getdisklabel __P((const char *, int));
74 static int readsb __P((int));
75 
76 /*
77  * Read in a superblock finding an alternate if necessary.
78  * Return 1 if successful, 0 if unsuccessful, -1 if filesystem
79  * is already clean (preen mode only).
80  */
81 int
82 setup(dev)
83 	const char *dev;
84 {
85 	long cg, size, asked, i, j;
86 	long bmapsize;
87 	struct disklabel *lp;
88 	off_t sizepb;
89 	struct stat statb;
90 	struct fs proto;
91 	int doskipclean;
92 	u_int64_t maxfilesize;
93 	struct csum *ccsp;
94 
95 	havesb = 0;
96 	fswritefd = -1;
97 	doskipclean = skipclean;
98 	if (stat(dev, &statb) < 0) {
99 		printf("Can't stat %s: %s\n", dev, strerror(errno));
100 		return (0);
101 	}
102 	if (forceimage) {
103 		if (!S_ISREG(statb.st_mode)) {
104 			pfatal("%s is not a regular file", dev);
105 			if (reply("CONTINUE") == 0)
106 				return (0);
107 		}
108 	} else if (!S_ISCHR(statb.st_mode)) {
109 		pfatal("%s is not a character device", dev);
110 		if (reply("CONTINUE") == 0)
111 			return (0);
112 	}
113 	if ((fsreadfd = open(dev, O_RDONLY)) < 0) {
114 		printf("Can't open %s: %s\n", dev, strerror(errno));
115 		return (0);
116 	}
117 	if (preen == 0)
118 		printf("** %s", dev);
119 	if (nflag || (fswritefd = open(dev, O_WRONLY)) < 0) {
120 		fswritefd = -1;
121 		if (preen)
122 			pfatal("NO WRITE ACCESS");
123 		printf(" (NO WRITE)");
124 	}
125 	if (preen == 0)
126 		printf("\n");
127 	fsmodified = 0;
128 	lfdir = 0;
129 	initbarea(&sblk);
130 	initbarea(&asblk);
131 	sblk.b_un.b_buf = malloc(SBSIZE);
132 	sblock = malloc(SBSIZE);
133 	asblk.b_un.b_buf = malloc(SBSIZE);
134 	altsblock = malloc(SBSIZE);
135 	if (sblk.b_un.b_buf == NULL || asblk.b_un.b_buf == NULL ||
136 		sblock == NULL || altsblock == NULL)
137 		errx(EEXIT, "cannot allocate space for superblock");
138 	if ((lp = getdisklabel(NULL, fsreadfd)) != NULL)
139 		dev_bsize = secsize = lp->d_secsize;
140 	else
141 		dev_bsize = secsize = DEV_BSIZE;
142 	/*
143 	 * Read in the superblock, looking for alternates if necessary
144 	 */
145 	if (readsb(1) == 0) {
146 		if (bflag || preen || calcsb(dev, fsreadfd, &proto) == 0)
147 			return(0);
148 		if (reply("LOOK FOR ALTERNATE SUPERBLOCKS") == 0)
149 			return (0);
150 		for (cg = 0; cg < proto.fs_ncg; cg++) {
151 			bflag = fsbtodb(&proto, cgsblock(&proto, cg));
152 			if (readsb(0) != 0)
153 				break;
154 		}
155 		if (cg >= proto.fs_ncg) {
156 			printf("%s %s\n%s %s\n%s %s\n",
157 				"SEARCH FOR ALTERNATE SUPER-BLOCK",
158 				"FAILED. YOU MUST USE THE",
159 				"-b OPTION TO fsck_ffs TO SPECIFY THE",
160 				"LOCATION OF AN ALTERNATE",
161 				"SUPER-BLOCK TO SUPPLY NEEDED",
162 				"INFORMATION; SEE fsck_ffs(8).");
163 			return(0);
164 		}
165 		doskipclean = 0;
166 		pwarn("USING ALTERNATE SUPERBLOCK AT %d\n", bflag);
167 	}
168 	if (debug)
169 		printf("clean = %d\n", sblock->fs_clean);
170 	if (doswap)
171 		doskipclean = 0;
172 	if (sblock->fs_clean & FS_ISCLEAN) {
173 		if (doskipclean) {
174 			pwarn("%sile system is clean; not checking\n",
175 			    preen ? "f" : "** F");
176 			return (-1);
177 		}
178 		if (!preen && !doswap)
179 			pwarn("** File system is already clean\n");
180 	}
181 	maxfsblock = sblock->fs_size;
182 	maxino = sblock->fs_ncg * sblock->fs_ipg;
183 	sizepb = sblock->fs_bsize;
184 	maxfilesize = sblock->fs_bsize * NDADDR - 1;
185 	for (i = 0; i < NIADDR; i++) {
186 		sizepb *= NINDIR(sblock);
187 		maxfilesize += sizepb;
188 	}
189 	/*
190 	 * Check and potentially fix certain fields in the super block.
191 	 */
192 	if (sblock->fs_optim != FS_OPTTIME && sblock->fs_optim != FS_OPTSPACE) {
193 		pfatal("UNDEFINED OPTIMIZATION IN SUPERBLOCK");
194 		if (reply("SET TO DEFAULT") == 1) {
195 			sblock->fs_optim = FS_OPTTIME;
196 			sbdirty();
197 		}
198 	}
199 	if ((sblock->fs_minfree < 0 || sblock->fs_minfree > 99)) {
200 		pfatal("IMPOSSIBLE MINFREE=%d IN SUPERBLOCK",
201 			sblock->fs_minfree);
202 		if (reply("SET TO DEFAULT") == 1) {
203 			sblock->fs_minfree = 10;
204 			sbdirty();
205 		}
206 	}
207 	if (sblock->fs_interleave < 1 ||
208 	    sblock->fs_interleave > sblock->fs_nsect) {
209 		pwarn("IMPOSSIBLE INTERLEAVE=%d IN SUPERBLOCK",
210 			sblock->fs_interleave);
211 		sblock->fs_interleave = 1;
212 		if (preen)
213 			printf(" (FIXED)\n");
214 		if (preen || reply("SET TO DEFAULT") == 1) {
215 			sbdirty();
216 			dirty(&asblk);
217 		}
218 	}
219 	if (sblock->fs_npsect < sblock->fs_nsect ||
220 	    sblock->fs_npsect > sblock->fs_nsect*2) {
221 		pwarn("IMPOSSIBLE NPSECT=%d IN SUPERBLOCK",
222 			sblock->fs_npsect);
223 		sblock->fs_npsect = sblock->fs_nsect;
224 		if (preen)
225 			printf(" (FIXED)\n");
226 		if (preen || reply("SET TO DEFAULT") == 1) {
227 			sbdirty();
228 			dirty(&asblk);
229 		}
230 	}
231 	if (sblock->fs_bmask != ~(sblock->fs_bsize - 1)) {
232 		pwarn("INCORRECT BMASK=0x%x IN SUPERBLOCK",
233 			sblock->fs_bmask);
234 		sblock->fs_bmask = ~(sblock->fs_bsize - 1);
235 		if (preen)
236 			printf(" (FIXED)\n");
237 		if (preen || reply("FIX") == 1) {
238 			sbdirty();
239 			dirty(&asblk);
240 		}
241 	}
242 	if (sblock->fs_fmask != ~(sblock->fs_fsize - 1)) {
243 		pwarn("INCORRECT FMASK=0x%x IN SUPERBLOCK",
244 			sblock->fs_fmask);
245 		sblock->fs_fmask = ~(sblock->fs_fsize - 1);
246 		if (preen)
247 			printf(" (FIXED)\n");
248 		if (preen || reply("FIX") == 1) {
249 			sbdirty();
250 			dirty(&asblk);
251 		}
252 	}
253 	if (sblock->fs_inodefmt >= FS_44INODEFMT) {
254 		if (sblock->fs_maxfilesize != maxfilesize) {
255 			pwarn("INCORRECT MAXFILESIZE=%lld IN SUPERBLOCK",
256 			    (unsigned long long)sblock->fs_maxfilesize);
257 			sblock->fs_maxfilesize = maxfilesize;
258 			if (preen)
259 				printf(" (FIXED)\n");
260 			if (preen || reply("FIX") == 1) {
261 				sbdirty();
262 				dirty(&asblk);
263 			}
264 		}
265 		if (sblock->fs_maxsymlinklen != MAXSYMLINKLEN) {
266 			pwarn("INCORRECT MAXSYMLINKLEN=%d IN SUPERBLOCK",
267 				sblock->fs_maxsymlinklen);
268 			sblock->fs_maxsymlinklen = MAXSYMLINKLEN;
269 			if (preen)
270 				printf(" (FIXED)\n");
271 			if (preen || reply("FIX") == 1) {
272 				sbdirty();
273 				dirty(&asblk);
274 			}
275 		}
276 		if (sblock->fs_qbmask != ~sblock->fs_bmask) {
277 			pwarn("INCORRECT QBMASK=%llx IN SUPERBLOCK",
278 			    (unsigned long long)sblock->fs_qbmask);
279 			sblock->fs_qbmask = ~sblock->fs_bmask;
280 			if (preen)
281 				printf(" (FIXED)\n");
282 			if (preen || reply("FIX") == 1) {
283 				sbdirty();
284 				dirty(&asblk);
285 			}
286 		}
287 		if (sblock->fs_qfmask != ~sblock->fs_fmask) {
288 			pwarn("INCORRECT QFMASK=%llx IN SUPERBLOCK",
289 			    (unsigned long long)sblock->fs_qfmask);
290 			sblock->fs_qfmask = ~sblock->fs_fmask;
291 			if (preen)
292 				printf(" (FIXED)\n");
293 			if (preen || reply("FIX") == 1) {
294 				sbdirty();
295 				dirty(&asblk);
296 			}
297 		}
298 		newinofmt = 1;
299 	} else {
300 		sblock->fs_qbmask = ~sblock->fs_bmask;
301 		sblock->fs_qfmask = ~sblock->fs_fmask;
302 		newinofmt = 0;
303 	}
304 	/*
305 	 * Convert to new inode format.
306 	 */
307 	if (cvtlevel >= 2 && sblock->fs_inodefmt < FS_44INODEFMT) {
308 		if (preen)
309 			pwarn("CONVERTING TO NEW INODE FORMAT\n");
310 		else if (!reply("CONVERT TO NEW INODE FORMAT"))
311 			return(0);
312 		doinglevel2++;
313 		sblock->fs_inodefmt = FS_44INODEFMT;
314 		sblock->fs_maxfilesize = maxfilesize;
315 		sblock->fs_maxsymlinklen = MAXSYMLINKLEN;
316 		sblock->fs_qbmask = ~sblock->fs_bmask;
317 		sblock->fs_qfmask = ~sblock->fs_fmask;
318 		sbdirty();
319 		dirty(&asblk);
320 	}
321 	/*
322 	 * Convert to new cylinder group format.
323 	 */
324 	if (cvtlevel >= 1 && sblock->fs_postblformat == FS_42POSTBLFMT) {
325 		if (preen)
326 			pwarn("CONVERTING TO NEW CYLINDER GROUP FORMAT\n");
327 		else if (!reply("CONVERT TO NEW CYLINDER GROUP FORMAT"))
328 			return(0);
329 		doinglevel1++;
330 		sblock->fs_postblformat = FS_DYNAMICPOSTBLFMT;
331 		sblock->fs_nrpos = 8;
332 		sblock->fs_postbloff =
333 		    (char *)(&sblock->fs_opostbl[0][0]) -
334 		    (char *)(&sblock->fs_firstfield);
335 		sblock->fs_rotbloff = &sblock->fs_space[0] -
336 		    (u_char *)(&sblock->fs_firstfield);
337 		sblock->fs_cgsize =
338 			fragroundup(sblock, CGSIZE(sblock));
339 		sbdirty();
340 		dirty(&asblk);
341 	}
342 	if (asblk.b_dirty && !bflag) {
343 		memmove((struct fs*)sblk.b_un.b_fs, sblock, SBSIZE);
344 		if (needswap)
345 			ffs_sb_swap(sblock, (struct fs*)sblk.b_un.b_fs);
346 		memmove(asblk.b_un.b_fs, sblk.b_un.b_fs, (size_t)sblock->fs_sbsize);
347 		flush(fswritefd, &asblk);
348 	}
349 	/*
350 	 * read in the summary info.
351 	 */
352 	asked = 0;
353 	sblock->fs_csp = (struct csum *)calloc(1, sblock->fs_cssize);
354 	for (i = 0, j = 0; i < sblock->fs_cssize; i += sblock->fs_bsize, j++) {
355 		size = sblock->fs_cssize - i < sblock->fs_bsize ?
356 		    sblock->fs_cssize - i : sblock->fs_bsize;
357 		ccsp = (struct csum *)((char *)sblock->fs_csp + i);
358 		if (bread(fsreadfd, (char *)ccsp,
359 		    fsbtodb(sblock, sblock->fs_csaddr + j * sblock->fs_frag),
360 		    size) != 0 && !asked) {
361 			pfatal("BAD SUMMARY INFORMATION");
362 			if (reply("CONTINUE") == 0) {
363 				markclean = 0;
364 				exit(EEXIT);
365 			}
366 			asked++;
367 		}
368 		if (doswap) {
369 			ffs_csum_swap(ccsp, ccsp, size);
370 			bwrite(fswritefd, (char *)ccsp,
371 			    fsbtodb(sblock,
372 				sblock->fs_csaddr + j * sblock->fs_frag),
373 			    size);
374 		}
375 		if (needswap)
376 			ffs_csum_swap(ccsp, ccsp, size);
377 	}
378 	/*
379 	 * allocate and initialize the necessary maps
380 	 */
381 	bmapsize = roundup(howmany(maxfsblock, NBBY), sizeof(int16_t));
382 	blockmap = calloc((unsigned)bmapsize, sizeof (char));
383 	if (blockmap == NULL) {
384 		printf("cannot alloc %u bytes for blockmap\n",
385 		    (unsigned)bmapsize);
386 		goto badsblabel;
387 	}
388 	statemap = calloc((unsigned)(maxino + 1), sizeof(char));
389 	if (statemap == NULL) {
390 		printf("cannot alloc %u bytes for statemap\n",
391 		    (unsigned)(maxino + 1));
392 		goto badsblabel;
393 	}
394 	typemap = calloc((unsigned)(maxino + 1), sizeof(char));
395 	if (typemap == NULL) {
396 		printf("cannot alloc %u bytes for typemap\n",
397 		    (unsigned)(maxino + 1));
398 		goto badsblabel;
399 	}
400 	lncntp = (int16_t *)calloc((unsigned)(maxino + 1), sizeof(int16_t));
401 	if (lncntp == NULL) {
402 		printf("cannot alloc %u bytes for lncntp\n",
403 		    (unsigned)((maxino + 1) * sizeof(int16_t)));
404 		goto badsblabel;
405 	}
406 	/*
407 	 * cs_ndir may be inaccurate, particularly if we're using the -b
408 	 * option, so set a minimum to prevent bogus subdirectory reconnects
409 	 * and really inefficient directory scans.
410 	 * Also set a maximum in case the value is too large.
411 	 */
412 	numdirs = sblock->fs_cstotal.cs_ndir;
413 	if (numdirs < 1024)
414 		numdirs = 1024;
415 	if (numdirs > maxino + 1)
416 		numdirs = maxino + 1;
417 	inplast = 0;
418 	listmax = numdirs + 10;
419 	inpsort = (struct inoinfo **)calloc((unsigned)listmax,
420 	    sizeof(struct inoinfo *));
421 	inphead = (struct inoinfo **)calloc((unsigned)numdirs,
422 	    sizeof(struct inoinfo *));
423 	if (inpsort == NULL || inphead == NULL) {
424 		printf("cannot alloc %u bytes for inphead\n",
425 		    (unsigned)(numdirs * sizeof(struct inoinfo *)));
426 		goto badsblabel;
427 	}
428 	cgrp = malloc(sblock->fs_cgsize);
429 	if (cgrp == NULL) {
430 		printf("cannot alloc %u bytes for cylinder group\n",
431 		    sblock->fs_cgsize);
432 		goto badsblabel;
433 	}
434 	bufinit();
435 	if (sblock->fs_flags & FS_DOSOFTDEP)
436 		usedsoftdep = 1;
437 	else
438 		usedsoftdep = 0;
439 	return (1);
440 
441 badsblabel:
442 	markclean=0;
443 	ckfini();
444 	return (0);
445 }
446 
447 /*
448  * Read in the super block and its summary info.
449  */
450 static int
451 readsb(listerr)
452 	int listerr;
453 {
454 	ufs_daddr_t super = bflag ? bflag : SBOFF / dev_bsize;
455 	struct fs *fs;
456 
457 	if (bread(fsreadfd, (char *)sblk.b_un.b_fs, super, (long)SBSIZE) != 0)
458 		return (0);
459 	sblk.b_bno = super;
460 	sblk.b_size = SBSIZE;
461 
462 	fs = sblk.b_un.b_fs;
463 	/* auto detect byte order */
464 	if( fs->fs_magic == FS_MAGIC) {
465 			if (endian == 0 || BYTE_ORDER == endian) {
466 				needswap = 0;
467 				doswap = do_blkswap = do_dirswap = 0;
468 			} else {
469 				needswap = 1;
470 				doswap = do_blkswap = do_dirswap = 1;
471 			}
472 	} else if (fs->fs_magic == bswap32(FS_MAGIC)) {
473 		if (endian == 0 || BYTE_ORDER != endian) {
474 			needswap = 1;
475 			doswap = do_blkswap = do_dirswap = 0;
476 		} else {
477 			needswap = 0;
478 			doswap = do_blkswap = do_dirswap = 1;
479 		}
480 	} else {
481 		badsb(listerr, "MAGIC NUMBER WRONG");
482 		return (0);
483 	}
484 	if (doswap) {
485 		if (preen)
486 			errx(EEXIT, "incompatible options -B and -p");
487 		if (nflag)
488 			errx(EEXIT, "incompatible options -B and -n");
489 		if (endian == LITTLE_ENDIAN) {
490 			if (!reply("CONVERT TO LITTLE ENDIAN"))
491 				return 0;
492 		} else if (endian == BIG_ENDIAN) {
493 			if (!reply("CONVERT TO BIG ENDIAN"))
494 				return 0;
495 		} else
496 			pfatal("INTERNAL ERROR: unknown endian");
497 	}
498 	if (needswap)
499 		printf("** Swapped byte order\n");
500 	/* swap SB byte order if asked */
501 	if (doswap)
502 		ffs_sb_swap(sblk.b_un.b_fs, sblk.b_un.b_fs);
503 
504 	memmove(sblock, sblk.b_un.b_fs, SBSIZE);
505 	if (needswap)
506 		ffs_sb_swap(sblk.b_un.b_fs, sblock);
507 
508 	/*
509 	 * run a few consistency checks of the super block
510 	 */
511 	if (sblock->fs_ncg < 1)
512 		{ badsb(listerr, "NCG OUT OF RANGE"); return (0); }
513 	if (sblock->fs_cpg < 1)
514 		{ badsb(listerr, "CPG OUT OF RANGE"); return (0); }
515 	if (sblock->fs_ncg * sblock->fs_cpg < sblock->fs_ncyl ||
516 	    (sblock->fs_ncg - 1) * sblock->fs_cpg >= sblock->fs_ncyl)
517 		{ badsb(listerr, "NCYL LESS THAN NCG*CPG"); return (0); }
518 	if (sblock->fs_sbsize > SBSIZE)
519 		{ badsb(listerr, "SIZE PREPOSTEROUSLY LARGE"); return (0); }
520 	/*
521 	 * Compute block size that the filesystem is based on,
522 	 * according to fsbtodb, and adjust superblock block number
523 	 * so we can tell if this is an alternate later.
524 	 */
525 	super *= dev_bsize;
526 	dev_bsize = sblock->fs_fsize / fsbtodb(sblock, 1);
527 	sblk.b_bno = super / dev_bsize;
528 
529 	if (bflag) {
530 		havesb = 1;
531 		return (1);
532 	}
533 	/*
534 	 * Set all possible fields that could differ, then do check
535 	 * of whole super block against an alternate super block.
536 	 * When an alternate super-block is specified this check is skipped.
537 	 */
538 	getblk(&asblk, cgsblock(sblock, sblock->fs_ncg - 1), sblock->fs_sbsize);
539 	if (asblk.b_errs)
540 		return (0);
541 	/* swap SB byte order if asked */
542 	if (doswap)
543 		ffs_sb_swap(asblk.b_un.b_fs, asblk.b_un.b_fs);
544 
545 	memmove(altsblock, asblk.b_un.b_fs, sblock->fs_sbsize);
546 	if (needswap)
547 		ffs_sb_swap(asblk.b_un.b_fs, altsblock);
548 	if (cmpsblks(sblock, altsblock)) {
549 		if (debug) {
550 			long *nlp, *olp, *endlp;
551 
552 			printf("superblock mismatches\n");
553 			nlp = (long *)altsblock;
554 			olp = (long *)sblock;
555 			endlp = olp + (sblock->fs_sbsize / sizeof *olp);
556 			for ( ; olp < endlp; olp++, nlp++) {
557 				if (*olp == *nlp)
558 					continue;
559 				printf("offset %ld, original %lx, alternate %lx\n",
560 				    (long)(olp - (long *)sblock), *olp, *nlp);
561 			}
562 		}
563 		badsb(listerr,
564 		"VALUES IN SUPER BLOCK DISAGREE WITH THOSE IN FIRST ALTERNATE");
565 		return (0);
566 	}
567 	/* Now we know the SB is valid, we can write it back if needed */
568 	if (doswap) {
569 		sbdirty();
570 		dirty(&asblk);
571 	}
572 	havesb = 1;
573 	return (1);
574 }
575 
576 int
577 cmpsblks(const struct fs *sb, struct fs *asb)
578 {
579 
580 	/*
581 	 * Copy fields which we don't care if they're different in the
582 	 * alternate superblocks, as they're either likely to be
583 	 * different because they're per-cylinder-group specific, or
584 	 * because they're transient details which are only maintained
585 	 * in the primary superblock.
586 	 */
587 	asb->fs_firstfield = sb->fs_firstfield;
588 	asb->fs_unused_1 = sb->fs_unused_1;
589 	asb->fs_time = sb->fs_time;
590 	asb->fs_cstotal = sb->fs_cstotal;
591 	asb->fs_cgrotor = sb->fs_cgrotor;
592 	asb->fs_fmod = sb->fs_fmod;
593 	asb->fs_clean = sb->fs_clean;
594 	asb->fs_ronly = sb->fs_ronly;
595 	asb->fs_flags = sb->fs_flags;
596 	asb->fs_maxcontig = sb->fs_maxcontig;
597 	asb->fs_minfree = sb->fs_minfree;
598 	asb->fs_optim = sb->fs_optim;
599 	asb->fs_rotdelay = sb->fs_rotdelay;
600 	asb->fs_maxbpg = sb->fs_maxbpg;
601 	memmove(asb->fs_ocsp, sb->fs_ocsp, sizeof sb->fs_ocsp);
602 	asb->fs_contigdirs = sb->fs_contigdirs;
603 	asb->fs_csp = sb->fs_csp;
604 	asb->fs_maxcluster = sb->fs_maxcluster;
605 	memmove(asb->fs_fsmnt, sb->fs_fsmnt, sizeof sb->fs_fsmnt);
606 	memmove(asb->fs_snapinum,
607 		sb->fs_snapinum, sizeof sb->fs_snapinum);
608 	asb->fs_avgfilesize = sb->fs_avgfilesize;
609 	asb->fs_avgfpdir = sb->fs_avgfpdir;
610 	memmove(asb->fs_sparecon,
611 		sb->fs_sparecon, sizeof sb->fs_sparecon);
612 	/*
613 	 * The following should not have to be copied, but need to be.
614 	 */
615 	asb->fs_fsbtodb = sb->fs_fsbtodb;
616 	asb->fs_interleave = sb->fs_interleave;
617 	asb->fs_npsect = sb->fs_npsect;
618 	asb->fs_nrpos = sb->fs_nrpos;
619 	asb->fs_qbmask = sb->fs_qbmask;
620 	asb->fs_qfmask = sb->fs_qfmask;
621 	asb->fs_state = sb->fs_state;
622 	asb->fs_maxfilesize = sb->fs_maxfilesize;
623 
624 	/*
625 	 * Compare the superblocks, effectively checking every other
626 	 * field to see if they differ.
627 	 */
628 	return (memcmp(sb, asb, (int)sb->fs_sbsize));
629 }
630 
631 static void
632 badsb(listerr, s)
633 	int listerr;
634 	char *s;
635 {
636 
637 	if (!listerr)
638 		return;
639 	if (preen)
640 		printf("%s: ", cdevname());
641 	pfatal("BAD SUPER BLOCK: %s\n", s);
642 }
643 
644 /*
645  * Calculate a prototype superblock based on information in the disk label.
646  * When done the cgsblock macro can be calculated and the fs_ncg field
647  * can be used. Do NOT attempt to use other macros without verifying that
648  * their needed information is available!
649  */
650 static int
651 calcsb(dev, devfd, fs)
652 	const char *dev;
653 	int devfd;
654 	struct fs *fs;
655 {
656 	struct disklabel *lp;
657 	struct partition *pp;
658 	char *cp;
659 	int i;
660 
661 	cp = strchr(dev, '\0') - 1;
662 	if ((cp == (char *)-1 || (*cp < 'a' || *cp > 'h')) && !isdigit(*cp)) {
663 		pfatal("%s: CANNOT FIGURE OUT FILE SYSTEM PARTITION\n", dev);
664 		return (0);
665 	}
666 	lp = getdisklabel(dev, devfd);
667 	if (isdigit(*cp))
668 		pp = &lp->d_partitions[0];
669 	else
670 		pp = &lp->d_partitions[*cp - 'a'];
671 	if (pp->p_fstype != FS_BSDFFS) {
672 		pfatal("%s: NOT LABELED AS A BSD FILE SYSTEM (%s)\n",
673 			dev, pp->p_fstype < FSMAXTYPES ?
674 			fstypenames[pp->p_fstype] : "unknown");
675 		return (0);
676 	}
677 	/* avoid divide by 0 */
678 	if (pp->p_fsize == 0 || pp->p_frag == 0)
679 		return (0);
680 	memset(fs, 0, sizeof(struct fs));
681 	fs->fs_fsize = pp->p_fsize;
682 	fs->fs_frag = pp->p_frag;
683 	fs->fs_cpg = pp->p_cpg;
684 	fs->fs_size = pp->p_size;
685 	fs->fs_ntrak = lp->d_ntracks;
686 	fs->fs_nsect = lp->d_nsectors;
687 	fs->fs_spc = lp->d_secpercyl;
688 	fs->fs_nspf = fs->fs_fsize / lp->d_secsize;
689 	fs->fs_sblkno = roundup(
690 		howmany(lp->d_bbsize + lp->d_sbsize, fs->fs_fsize),
691 		fs->fs_frag);
692 	fs->fs_cgmask = 0xffffffff;
693 	for (i = fs->fs_ntrak; i > 1; i >>= 1)
694 		fs->fs_cgmask <<= 1;
695 	if (!POWEROF2(fs->fs_ntrak))
696 		fs->fs_cgmask <<= 1;
697 	fs->fs_cgoffset = roundup(
698 		howmany(fs->fs_nsect, NSPF(fs)), fs->fs_frag);
699 	fs->fs_fpg = (fs->fs_cpg * fs->fs_spc) / NSPF(fs);
700 	fs->fs_ncg = howmany(fs->fs_size / fs->fs_spc, fs->fs_cpg);
701 	for (fs->fs_fsbtodb = 0, i = NSPF(fs); i > 1; i >>= 1)
702 		fs->fs_fsbtodb++;
703 	dev_bsize = lp->d_secsize;
704 	return (1);
705 }
706 
707 static struct disklabel *
708 getdisklabel(s, fd)
709 	const char *s;
710 	int	fd;
711 {
712 	static struct disklabel lab;
713 
714 	if (ioctl(fd, DIOCGDINFO, (char *)&lab) < 0) {
715 		if (s == NULL)
716 			return ((struct disklabel *)NULL);
717 		pwarn("ioctl (GCINFO): %s\n", strerror(errno));
718 		errx(EEXIT, "%s: can't read disk label", s);
719 	}
720 	return (&lab);
721 }
722