/*      $NetBSD: setup.c,v 1.112 2025/12/18 08:21:44 nia Exp $  */

/*
 * Copyright (c) 1980, 1986, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
#ifndef lint
#if 0
static char sccsid[] = "@(#)setup.c     8.10 (Berkeley) 5/9/95";
#else
__RCSID("$NetBSD: setup.c,v 1.112 2025/12/18 08:21:44 nia Exp $");
#endif
#endif /* not lint */

#include <sys/param.h>
#include <sys/time.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <sys/file.h>
#include <sys/disk.h>

#include <ufs/ufs/dinode.h>
#include <ufs/ufs/dir.h>
#include <ufs/ufs/ufs_bswap.h>
#include <ufs/ufs/quota2.h>
#include <ufs/ffs/fs.h>
#include <ufs/ffs/ffs_extern.h>

#include <ctype.h>
#include <err.h>
#include <errno.h>
#include <endian.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "fsck.h"
#include "extern.h"
#include "fsutil.h"
#include "partutil.h"
#include "exitvalues.h"

#define POWEROF2(num)   (((num) & ((num) - 1)) == 0)

static void badsb(int, const char *);
static int calcsb(const char *, int, struct fs *);
static int readsb(int);
#ifndef NO_APPLE_UFS
static int readappleufs(void);
#endif
static int check_snapinum(void);

int16_t sblkpostbl[256];

/*
 * Read in a superblock finding an alternate if necessary.
 * Return 1 if successful, 0 if unsuccessful, -1 if filesystem
 * is already clean (preen mode only).
 */
int
setup(const char *dev, const char *origdev)
{
        uint32_t cg;
        long size, asked, i, j;
        size_t bmapsize;
        struct disk_geom geo;
        struct dkwedge_info dkw;
        off_t sizepb;
        struct stat statb;
        struct fs proto;
        int doskipclean;
        u_int64_t maxfilesize;
        struct csum *ccsp;
        int fd;

        havesb = 0;
        fswritefd = -1;
        doskipclean = skipclean;
        if (stat(dev, &statb) < 0) {
                printf("Can't stat %s: %s\n", dev, strerror(errno));
                return (0);
        }
        if (!forceimage && !S_ISCHR(statb.st_mode)) {
                pfatal("%s is not a character device", dev);
                if (reply("CONTINUE") == 0)
                        return (0);
        }
        if ((fsreadfd = open(dev, O_RDONLY)) < 0) {
                printf("Can't open %s: %s\n", dev, strerror(errno));
                return (0);
        }
        if (nflag || (fswritefd = open(dev, O_WRONLY)) < 0) {
                fswritefd = -1;
                if (preen)
                        pfatal("NO WRITE ACCESS");
                printf("** %s (NO WRITE)\n", dev);
                quiet = 0;
        } else
                if (!preen && !quiet)
                        printf("** %s\n", dev);
        fsmodified = 0;
        lfdir = 0;
        initbarea(&sblk);
        initbarea(&asblk);
        sblk.b_un.b_buf = aligned_alloc(DEV_BSIZE, SBLOCKSIZE);
        sblock = aligned_alloc(DEV_BSIZE, SBLOCKSIZE);
        asblk.b_un.b_buf = aligned_alloc(DEV_BSIZE, SBLOCKSIZE);
        altsblock = aligned_alloc(DEV_BSIZE, SBLOCKSIZE);
        if (sblk.b_un.b_buf == NULL || asblk.b_un.b_buf == NULL ||
                sblock == NULL || altsblock == NULL)
                errexit("Cannot allocate space for superblock");
        if (strcmp(dev, origdev) && !forceimage) {
                /*
                 * dev isn't the original fs (for example it's a snapshot)
                 * do getdiskinfo on the original device
                 */
                 fd = open(origdev, O_RDONLY);
                 if (fd < 0) {
                        warn("Can't open %s", origdev);
                        return (0);
                }
        } else {
                fd = fsreadfd;
        }
        if (!forceimage && getdiskinfo(origdev, fd, NULL, &geo, &dkw) != -1)
                dev_bsize = secsize = geo.dg_secsize;
        else
                dev_bsize = secsize = DEV_BSIZE;
        /*
         * Read in the superblock, looking for alternates if necessary
         */
        if (readsb(1) == 0) {
                if (bflag || preen || forceimage ||
                    calcsb(dev, fsreadfd, &proto) == 0)
                        return(0);
                if (reply("LOOK FOR ALTERNATE SUPERBLOCKS") == 0)
                        return (0);
                for (cg = 0; cg < proto.fs_ncg; cg++) {
                        bflag = FFS_FSBTODB(&proto, cgsblock(&proto, cg));
                        if (readsb(0) != 0)
                                break;
                }
                if (cg >= proto.fs_ncg) {
                        printf("%s %s\n%s %s\n%s %s\n",
                                "SEARCH FOR ALTERNATE SUPER-BLOCK",
                                "FAILED. YOU MUST USE THE",
                                "-b OPTION TO fsck_ffs TO SPECIFY THE",
                                "LOCATION OF AN ALTERNATE",
                                "SUPER-BLOCK TO SUPPLY NEEDED",
                                "INFORMATION; SEE fsck_ffs(8).");
                        return(0);
                }
                doskipclean = 0;
                pwarn("USING ALTERNATE SUPERBLOCK AT %d\n", bflag);
        }

        if (!quota2_check_doquota())
                doskipclean = 0;

        /* ffs_superblock_layout() == 2 */
        if (sblock->fs_magic != FS_UFS1_MAGIC ||
            (sblock->fs_old_flags & FS_FLAGS_UPDATED) != 0) {
                /* can have WAPBL */
                if (check_wapbl() != 0) {
                        doskipclean = 0;
                }
                if (sblock->fs_flags & FS_DOWAPBL) {
                        if (preen && doskipclean) {
                                if (!quiet)
                                        pwarn("file system is journaled; "
                                            "not checking\n");
                                return (-1);
                        }
                        if (!quiet)
                                pwarn("** File system is journaled; "
                                    "replaying journal\n");
                        replay_wapbl();
                        doskipclean = 0;
                        sblock->fs_flags &= ~FS_DOWAPBL;
                        sbdirty();
                        /* Although we may have updated the superblock from
                         * the journal, we are still going to do a full check,
                         * so we don't bother to re-read the superblock from
                         * the journal.
                         * XXX, instead we could re-read the superblock and
                         * then not force doskipclean = 0
                         */
                }
        }
        if (debug)
                printf("clean = %d\n", sblock->fs_clean);

        if (doswap)
                doskipclean = 0;

        if (sblock->fs_clean & FS_ISCLEAN) {
                if (doskipclean) {
                        if (!quiet)
                                pwarn("%sile system is clean; not checking\n",
                                    preen ? "f" : "** F");
                        return (-1);
                }
                if (!preen && !doswap)
                        pwarn("** File system is already clean\n");
        }
        maxfsblock = sblock->fs_size;
        maxino = sblock->fs_ncg * sblock->fs_ipg;
        sizepb = sblock->fs_bsize;
        maxfilesize = sblock->fs_bsize * UFS_NDADDR - 1;
        for (i = 0; i < UFS_NIADDR; i++) {
                sizepb *= FFS_NINDIR(sblock);
                maxfilesize += sizepb;
        }
        if ((!is_ufs2 && cvtlevel >= 4) &&
                        (sblock->fs_old_flags & FS_FLAGS_UPDATED) == 0) {
                if (preen)
                        pwarn("CONVERTING TO NEW SUPERBLOCK LAYOUT\n");
                else if (!reply("CONVERT TO NEW SUPERBLOCK LAYOUT"))
                        return(0);
                sblock->fs_old_flags |= FS_FLAGS_UPDATED;
                /* Disable the postbl tables */
                sblock->fs_old_cpc = 0;
                sblock->fs_old_nrpos = 1;
                sblock->fs_old_trackskew = 0;
                /* The other fields have already been updated by
                 * sb_oldfscompat_read
                 */
                sbdirty();
        }
        if (!is_ufs2 && cvtlevel == 3 &&
            (sblock->fs_old_flags & FS_FLAGS_UPDATED)) {
                if (preen)
                        pwarn("DOWNGRADING TO OLD SUPERBLOCK LAYOUT\n");
                else if (!reply("DOWNGRADE TO OLD SUPERBLOCK LAYOUT"))
                        return(0);
                sblock->fs_old_flags &= ~FS_FLAGS_UPDATED;
                sb_oldfscompat_write(sblock, sblock);
                sblock->fs_old_flags &= ~FS_FLAGS_UPDATED; /* just in case */
                /* Leave postbl tables disabled, but blank its superblock region anyway */
                sblock->fs_old_postblformat = FS_DYNAMICPOSTBLFMT;
                sblock->fs_old_cpc = 0;
                sblock->fs_old_nrpos = 1;
                sblock->fs_old_trackskew = 0;
                memset(&sblock->fs_old_postbl_start, 0xff, 256);
                sb_oldfscompat_read(sblock, &sblocksave);
                sbdirty();
        }
        /*
         * Check and potentially fix certain fields in the super block.
         */
        if (sblock->fs_flags & ~(FS_KNOWN_FLAGS)) {
                pfatal("UNKNOWN FLAGS=0x%08x IN SUPERBLOCK", sblock->fs_flags);
                if (reply("CLEAR") == 1) {
                        sblock->fs_flags &= FS_KNOWN_FLAGS;
                        sbdirty();
                }
        }
        if (sblock->fs_optim != FS_OPTTIME && sblock->fs_optim != FS_OPTSPACE) {
                pfatal("UNDEFINED OPTIMIZATION IN SUPERBLOCK");
                if (reply("SET TO DEFAULT") == 1) {
                        sblock->fs_optim = FS_OPTTIME;
                        sbdirty();
                }
        }
        if ((sblock->fs_minfree < 0 || sblock->fs_minfree > 99)) {
                pfatal("IMPOSSIBLE MINFREE=%d IN SUPERBLOCK",
                        sblock->fs_minfree);
                if (reply("SET TO DEFAULT") == 1) {
                        sblock->fs_minfree = 10;
                        sbdirty();
                }
        }
        if (!is_ufs2 && sblock->fs_old_postblformat != FS_42POSTBLFMT &&
            (sblock->fs_old_interleave < 1 ||
            sblock->fs_old_interleave > sblock->fs_old_nsect)) {
                pwarn("IMPOSSIBLE INTERLEAVE=%d IN SUPERBLOCK",
                        sblock->fs_old_interleave);
                sblock->fs_old_interleave = 1;
                if (preen)
                        printf(" (FIXED)\n");
                if (preen || reply("SET TO DEFAULT") == 1) {
                        sbdirty();
                        dirty(&asblk);
                }
        }
        if (!is_ufs2 && sblock->fs_old_postblformat != FS_42POSTBLFMT &&
            (sblock->fs_old_npsect < sblock->fs_old_nsect ||
            sblock->fs_old_npsect > sblock->fs_old_nsect*2)) {
                pwarn("IMPOSSIBLE NPSECT=%d IN SUPERBLOCK",
                        sblock->fs_old_npsect);
                sblock->fs_old_npsect = sblock->fs_old_nsect;
                if (preen)
                        printf(" (FIXED)\n");
                if (preen || reply("SET TO DEFAULT") == 1) {
                        sbdirty();
                        dirty(&asblk);
                }
        }
        if (sblock->fs_bmask != ~(sblock->fs_bsize - 1)) {
                pwarn("INCORRECT BMASK=0x%x IN SUPERBLOCK",
                        sblock->fs_bmask);
                sblock->fs_bmask = ~(sblock->fs_bsize - 1);
                if (preen)
                        printf(" (FIXED)\n");
                if (preen || reply("FIX") == 1) {
                        sbdirty();
                        dirty(&asblk);
                }
        }
        if (sblock->fs_fmask != ~(sblock->fs_fsize - 1)) {
                pwarn("INCORRECT FMASK=0x%x IN SUPERBLOCK",
                        sblock->fs_fmask);
                sblock->fs_fmask = ~(sblock->fs_fsize - 1);
                if (preen)
                        printf(" (FIXED)\n");
                if (preen || reply("FIX") == 1) {
                        sbdirty();
                        dirty(&asblk);
                }
        }
        if (check_snapinum()) {
                if (preen)
                        printf(" (FIXED)\n");
                if (preen || reply("FIX") == 1) {
                        sbdirty();
                        dirty(&asblk);
                }
        }
        if (is_ufs2 || sblock->fs_old_inodefmt >= FS_44INODEFMT) {
                if (sblock->fs_maxfilesize != maxfilesize) {
                        pwarn("INCORRECT MAXFILESIZE=%lld IN SUPERBLOCK",
                            (unsigned long long)sblock->fs_maxfilesize);
                        sblock->fs_maxfilesize = maxfilesize;
                        if (preen)
                                printf(" (FIXED)\n");
                        if (preen || reply("FIX") == 1) {
                                sbdirty();
                                dirty(&asblk);
                        }
                }
                if ((is_ufs2 && sblock->fs_maxsymlinklen != UFS2_MAXSYMLINKLEN)
                    ||
                   (!is_ufs2 && sblock->fs_maxsymlinklen != UFS1_MAXSYMLINKLEN))
                    {
                        pwarn("INCORRECT MAXSYMLINKLEN=%d IN SUPERBLOCK",
                                sblock->fs_maxsymlinklen);
                        sblock->fs_maxsymlinklen = is_ufs2 ?
                            UFS2_MAXSYMLINKLEN : UFS1_MAXSYMLINKLEN;
                        if (preen)
                                printf(" (FIXED)\n");
                        if (preen || reply("FIX") == 1) {
                                sbdirty();
                                dirty(&asblk);
                        }
                }
                if (sblock->fs_qbmask != ~sblock->fs_bmask) {
                        pwarn("INCORRECT QBMASK=%#llx IN SUPERBLOCK",
                            (unsigned long long)sblock->fs_qbmask);
                        sblock->fs_qbmask = ~sblock->fs_bmask;
                        if (preen)
                                printf(" (FIXED)\n");
                        if (preen || reply("FIX") == 1) {
                                sbdirty();
                                dirty(&asblk);
                        }
                }
                if (sblock->fs_qfmask != ~sblock->fs_fmask) {
                        pwarn("INCORRECT QFMASK=%#llx IN SUPERBLOCK",
                            (unsigned long long)sblock->fs_qfmask);
                        sblock->fs_qfmask = ~sblock->fs_fmask;
                        if (preen)
                                printf(" (FIXED)\n");
                        if (preen || reply("FIX") == 1) {
                                sbdirty();
                                dirty(&asblk);
                        }
                }
                newinofmt = 1;
        } else {
                sblock->fs_qbmask = ~sblock->fs_bmask;
                sblock->fs_qfmask = ~sblock->fs_fmask;
                newinofmt = 0;
        }
        /*
         * Convert to new inode format.
         */
        if (!is_ufs2 && cvtlevel >= 2 &&
            sblock->fs_old_inodefmt < FS_44INODEFMT) {
                if (preen)
                        pwarn("CONVERTING TO NEW INODE FORMAT\n");
                else if (!reply("CONVERT TO NEW INODE FORMAT"))
                        return(0);
                doinglevel2++;
                sblock->fs_old_inodefmt = FS_44INODEFMT;
                sblock->fs_maxfilesize = maxfilesize;
                sblock->fs_maxsymlinklen = UFS1_MAXSYMLINKLEN;
                sblock->fs_qbmask = ~sblock->fs_bmask;
                sblock->fs_qfmask = ~sblock->fs_fmask;
                sbdirty();
                dirty(&asblk);
        }
        /*
         * Convert to new cylinder group format.
         */
        if (!is_ufs2 && cvtlevel >= 1 &&
            sblock->fs_old_postblformat == FS_42POSTBLFMT) {
                if (preen)
                        pwarn("CONVERTING TO NEW CYLINDER GROUP FORMAT\n");
                else if (!reply("CONVERT TO NEW CYLINDER GROUP FORMAT"))
                        return(0);
                doinglevel1++;
                sblock->fs_old_postblformat = FS_DYNAMICPOSTBLFMT;
                sblock->fs_old_nrpos = 8;
                sblock->fs_old_postbloff =
                    (char *)(&sblock->fs_old_postbl_start) -
                    (char *)(&sblock->fs_firstfield);
                sblock->fs_old_rotbloff =
                                (char *)(&sblock->fs_magic+1) -
                                (char *)(&sblock->fs_firstfield);
                sblock->fs_cgsize =
                        ffs_fragroundup(sblock, CGSIZE(sblock));
                sbdirty();
                dirty(&asblk);
        }
        if (asblk.b_dirty && !bflag) {
                memmove(sblk.b_un.b_fs, sblock, SBLOCKSIZE);
                sb_oldfscompat_write(sblk.b_un.b_fs, sblocksave);
                if (needswap)
                        ffs_sb_swap(sblk.b_un.b_fs, sblk.b_un.b_fs);
                memmove(asblk.b_un.b_fs, sblk.b_un.b_fs, (size_t)sblock->fs_sbsize);
                flush(fswritefd, &asblk);
        }
        /*
         * read in the summary info.
         */
        asked = 0;
        sblock->fs_csp = (struct csum *)aligned_alloc(DEV_BSIZE,
            sblock->fs_cssize);
        if (sblock->fs_csp == NULL) {
                pwarn("cannot alloc %u bytes for summary info\n",
                    sblock->fs_cssize);
                goto badsblabel;
        }
        memset(sblock->fs_csp, 0, sblock->fs_cssize);
        for (i = 0, j = 0; i < sblock->fs_cssize; i += sblock->fs_bsize, j++) {
                size = sblock->fs_cssize - i < sblock->fs_bsize ?
                    sblock->fs_cssize - i : sblock->fs_bsize;
                ccsp = (struct csum *)((char *)sblock->fs_csp + i);
                if (bread(fsreadfd, (char *)ccsp,
                    FFS_FSBTODB(sblock, sblock->fs_csaddr + j * sblock->fs_frag),
                    size) != 0 && !asked) {
                        pfatal("BAD SUMMARY INFORMATION");
                        if (reply("CONTINUE") == 0) {
                                markclean = 0;
                                exit(FSCK_EXIT_CHECK_FAILED);
                        }
                        asked++;
                }
                if (doswap) {
                        ffs_csum_swap(ccsp, ccsp, size);
                        bwrite(fswritefd, (char *)ccsp,
                            FFS_FSBTODB(sblock,
                                sblock->fs_csaddr + j * sblock->fs_frag),
                            size);
                }
                if (needswap)
                        ffs_csum_swap(ccsp, ccsp, size);
        }
        /*
         * allocate and initialize the necessary maps
         */
        bmapsize = roundup(howmany(maxfsblock, NBBY), sizeof(int16_t));
        blockmap = aligned_alloc(DEV_BSIZE, bmapsize);
        if (blockmap == NULL) {
                pwarn("cannot alloc %zu bytes for blockmap\n", bmapsize);
                goto badsblabel;
        }
        memset(blockmap, 0, bmapsize);
        inostathead = calloc((unsigned)(sblock->fs_ncg),
            sizeof(struct inostatlist));
        if (inostathead == NULL) {
                pwarn("cannot alloc %u bytes for inostathead\n",
                    (unsigned)(sizeof(struct inostatlist) * (sblock->fs_ncg)));
                goto badsblabel;
        }
        /*
         * cs_ndir may be inaccurate, particularly if we're using the -b
         * option, so set a minimum to prevent bogus subdirectory reconnects
         * and really inefficient directory scans.
         * Also set a maximum in case the value is too large.
         */
        numdirs = sblock->fs_cstotal.cs_ndir;
        if (numdirs < 1024)
                numdirs = 1024;
        if ((ino_t)numdirs > maxino + 1)
                numdirs = maxino + 1;
        dirhash = numdirs;
        inplast = 0;
        listmax = numdirs + 10;
        inpsort = calloc((unsigned)listmax, sizeof(*inpsort));
        inphead = calloc((unsigned)numdirs, sizeof(*inphead));
        if (inpsort == NULL || inphead == NULL) {
                pwarn("cannot alloc %u bytes for inphead\n",
                    (unsigned)(numdirs * sizeof(struct inoinfo *)));
                goto badsblabel;
        }
        cgrp = aligned_alloc(DEV_BSIZE, sblock->fs_cgsize);
        if (cgrp == NULL) {
                pwarn("cannot alloc %u bytes for cylinder group\n",
                    sblock->fs_cgsize);
                goto badsblabel;
        }
        bufinit();
        if (sblock->fs_flags & FS_DOSOFTDEP)
                usedsoftdep = 1;
        else
                usedsoftdep = 0;

#ifndef NO_APPLE_UFS
        if (!forceimage && dkw.dkw_parent[0])
                if (strcmp(dkw.dkw_ptype, DKW_PTYPE_APPLEUFS) == 0)
                        isappleufs = 1;

        if (readappleufs())
                isappleufs = 1;
#endif

        if (isappleufs)
                dirblksiz = APPLEUFS_DIRBLKSIZ;
        else
                dirblksiz = UFS_DIRBLKSIZ;

        if (debug)
#ifndef NO_APPLE_UFS
                printf("isappleufs = %d, dirblksiz = %d\n", isappleufs, dirblksiz);
#else
                printf("dirblksiz = %d\n", dirblksiz);
#endif

        if (sblock->fs_flags & FS_DOQUOTA2) {
                /* allocate the quota hash table */
                /*
                 * first compute the size of the hash table
                 * We know the smallest block size is 4k, so we can use 2k
                 * for the hash table; as an entry is 8 bytes we can store
                 * 256 entries. So let start q2h_hash_shift at 8
                 */
                for (q2h_hash_shift = 8;
                    q2h_hash_shift < 15;
                    q2h_hash_shift++) {
                        if ((sizeof(uint64_t) << (q2h_hash_shift + 1)) +
                            sizeof(struct quota2_header) >
                            (size_t)sblock->fs_bsize)
                                break;
                }
                q2h_hash_mask = (1 << q2h_hash_shift) - 1;
                if (debug) {
                        printf("quota hash shift %d, %d entries, mask 0x%x\n",
                            q2h_hash_shift, (1 << q2h_hash_shift),
                            q2h_hash_mask);
                }
                uquot_user_hash =
                    calloc((1 << q2h_hash_shift), sizeof(struct uquot_hash));
                uquot_group_hash =
                    calloc((1 << q2h_hash_shift), sizeof(struct uquot_hash));
                if (uquot_user_hash == NULL || uquot_group_hash == NULL)
                        errexit("Cannot allocate space for quotas hash\n");
        } else {
                uquot_user_hash = uquot_group_hash = NULL;
                q2h_hash_shift = q2h_hash_mask = 0;
        }
        return (1);
badsblabel:
        markclean=0;
        ckfini(1);
        return (0);
}

#ifndef NO_APPLE_UFS
static int
readappleufs(void)
{
        daddr_t label = APPLEUFS_LABEL_OFFSET / dev_bsize;
        struct appleufslabel *appleufs;
        int i;

        /* XXX do we have to deal with APPLEUFS_LABEL_OFFSET not
         * being block aligned (CD's?)
         */
        if (APPLEUFS_LABEL_SIZE % dev_bsize != 0)
                return 0;
        if (bread(fsreadfd, (char *)appleufsblk.b_un.b_fs, label,
            (long)APPLEUFS_LABEL_SIZE) != 0)
                return 0;
        appleufsblk.b_bno = label;
        appleufsblk.b_size = APPLEUFS_LABEL_SIZE;

        appleufs = appleufsblk.b_un.b_appleufs;

        if (ntohl(appleufs->ul_magic) != APPLEUFS_LABEL_MAGIC) {
                if (!isappleufs) {
                        return 0;
                } else {
                        pfatal("MISSING APPLEUFS VOLUME LABEL\n");
                        if (reply("FIX") == 0) {
                                return 1;
                        }
                        ffs_appleufs_set(appleufs, NULL, -1, 0);
                        appleufsdirty();
                }
        }

        if (ntohl(appleufs->ul_version) != APPLEUFS_LABEL_VERSION) {
                pwarn("INCORRECT APPLE UFS VERSION NUMBER (%d should be %d)",
                        ntohl(appleufs->ul_version),APPLEUFS_LABEL_VERSION);
                if (preen) {
                        printf(" (CORRECTED)\n");
                }
                if (preen || reply("CORRECT")) {
                        appleufs->ul_version = htonl(APPLEUFS_LABEL_VERSION);
                        appleufsdirty();
                }
        }

        if (ntohs(appleufs->ul_namelen) > APPLEUFS_MAX_LABEL_NAME) {
                pwarn("APPLE UFS LABEL NAME TOO LONG");
                if (preen) {
                        printf(" (TRUNCATED)\n");
                }
                if (preen || reply("TRUNCATE")) {
                        appleufs->ul_namelen = htons(APPLEUFS_MAX_LABEL_NAME);
                        appleufsdirty();
                }
        }

        if (ntohs(appleufs->ul_namelen) == 0) {
                pwarn("MISSING APPLE UFS LABEL NAME");
                if (preen) {
                        printf(" (FIXED)\n");
                }
                if (preen || reply("FIX")) {
                        ffs_appleufs_set(appleufs, NULL, -1, 0);
                        appleufsdirty();
                }
        }

        /* Scan name for first illegal character */
        for (i=0;i<ntohs(appleufs->ul_namelen);i++) {
                if ((appleufs->ul_name[i] == '\0') ||
                        (appleufs->ul_name[i] == ':') ||
                        (appleufs->ul_name[i] == '/')) {
                        pwarn("APPLE UFS LABEL NAME CONTAINS ILLEGAL CHARACTER");
                        if (preen) {
                                printf(" (TRUNCATED)\n");
                        }
                        if (preen || reply("TRUNCATE")) {
                                appleufs->ul_namelen = i+1;
                                appleufsdirty();
                        }
                        break;
                }
        }

        /* Check the checksum last, because if anything else was wrong,
         * then the checksum gets reset anyway.
         */
        appleufs->ul_checksum = 0;
        appleufs->ul_checksum = ffs_appleufs_cksum(appleufs);
        if (appleufsblk.b_un.b_appleufs->ul_checksum != appleufs->ul_checksum) {
                pwarn("INVALID APPLE UFS CHECKSUM (%#04x should be %#04x)",
                        appleufsblk.b_un.b_appleufs->ul_checksum, appleufs->ul_checksum);
                if (preen) {
                        printf(" (CORRECTED)\n");
                }
                if (preen || reply("CORRECT")) {
                        appleufsdirty();
                } else {
                        /* put the incorrect checksum back in place */
                        appleufs->ul_checksum = appleufsblk.b_un.b_appleufs->ul_checksum;
                }
        }
        return 1;
}
#endif /* !NO_APPLE_UFS */

/*
 * Detect byte order. Return 0 if valid magic found, -1 otherwise.
 */
static int
detect_byteorder(struct fs *fs, int sblockoff)
{
        if (sblockoff == SBLOCK_UFS2 && (fs->fs_magic == FS_UFS1_MAGIC ||
            fs->fs_magic == FS_UFS1_MAGIC_SWAPPED))
                /* Likely to be the first alternate of a fs with 64k blocks */
                return -1;
        if (fs->fs_magic == FS_UFS1_MAGIC || fs->fs_magic == FS_UFS2_MAGIC ||
            fs->fs_magic == FS_UFS2EA_MAGIC) {
#ifndef NO_FFS_EI
                if (endian == 0 || BYTE_ORDER == endian) {
                        needswap = 0;
                        doswap = do_blkswap = do_dirswap = 0;
                } else {
                        needswap = 1;
                        doswap = do_blkswap = do_dirswap = 1;
                }
#endif
                return 0;
        }
#ifndef NO_FFS_EI
        else if (fs->fs_magic == FS_UFS1_MAGIC_SWAPPED ||
                 fs->fs_magic == FS_UFS2_MAGIC_SWAPPED ||
                 fs->fs_magic == FS_UFS2EA_MAGIC_SWAPPED) {
                if (endian == 0 || BYTE_ORDER != endian) {
                        needswap = 1;
                        doswap = do_blkswap = do_dirswap = 0;
                } else {
                        needswap = 0;
                        doswap = do_blkswap = do_dirswap = 1;
                }
                return 0;
        }
#endif
        return -1;
}

/* Update on-disk fs->fs_magic if we are converting */
void
cvt_magic(struct fs *fs)
{

        if (is_ufs2ea || doing2ea) {
                if (fs->fs_magic == FS_UFS2_MAGIC) {
                        fs->fs_magic = FS_UFS2EA_MAGIC;
                }
                if (fs->fs_magic == FS_UFS2_MAGIC_SWAPPED) {
                        fs->fs_magic = FS_UFS2EA_MAGIC_SWAPPED;
                }
        }
        if (doing2noea) {
                if (fs->fs_magic == FS_UFS2EA_MAGIC) {
                        fs->fs_magic = FS_UFS2_MAGIC;
                }
                if (fs->fs_magic == FS_UFS2EA_MAGIC_SWAPPED) {
                        fs->fs_magic = FS_UFS2_MAGIC_SWAPPED;
                }
        }
}

/*
 * Possible superblock locations ordered from most to least likely.
 */
static off_t sblock_try[] = SBLOCKSEARCH;

/*
 * Read in the super block and its summary info.
 */
static int
readsb(int listerr)
{
        daddr_t super = 0;
        struct fs *fs;
        int i;

        if (bflag) {
                super = bflag;
                if (bread(fsreadfd, (char *)sblk.b_un.b_fs, super,
                    (long)SBLOCKSIZE) != 0)
                        return (0);
                fs = sblk.b_un.b_fs;
                if (detect_byteorder(fs, -1) < 0) {
                        badsb(listerr, "MAGIC NUMBER WRONG");
                        return (0);
                }
        } else {
                for (i = 0; sblock_try[i] != -1; i++) {
                        super = sblock_try[i] / dev_bsize;
                        if (bread(fsreadfd, (char *)sblk.b_un.b_fs,
                            super, (long)SBLOCKSIZE) != 0)
                                continue;
                        fs = sblk.b_un.b_fs;
                        if (detect_byteorder(fs, sblock_try[i]) == 0)
                                break;
                }
                if (sblock_try[i] == -1) {
                        badsb(listerr, "CAN'T FIND SUPERBLOCK");
                        return (0);
                }
        }
        if (doswap) {
                if (preen)
                        errx(FSCK_EXIT_USAGE,
                            "Incompatible options -B and -p");
                if (nflag)
                        errx(FSCK_EXIT_USAGE,
                            "Incompatible options -B and -n");
                if (endian == LITTLE_ENDIAN) {
                        if (!reply("CONVERT TO LITTLE ENDIAN"))
                                return 0;
                } else if (endian == BIG_ENDIAN) {
                        if (!reply("CONVERT TO BIG ENDIAN"))
                                return 0;
                } else
                        pfatal("INTERNAL ERROR: unknown endian");
        }
        if (needswap)
                pwarn("** Swapped byte order\n");
        /* swap SB byte order if asked */
        if (doswap)
                ffs_sb_swap(sblk.b_un.b_fs, sblk.b_un.b_fs);

        memmove(sblock, sblk.b_un.b_fs, SBLOCKSIZE);
        if (needswap)
                ffs_sb_swap(sblk.b_un.b_fs, sblock);
        if (sblock->fs_magic == FS_UFS2EA_MAGIC) {
                is_ufs2ea = 1;
                sblock->fs_magic = FS_UFS2_MAGIC;
        }
        is_ufs2 = sblock->fs_magic == FS_UFS2_MAGIC;

        /* change on-disk magic if asked */
        cvt_magic(fs);

        /*
         * run a few consistency checks of the super block
         */
        if (sblock->fs_sbsize > SBLOCKSIZE)
                { badsb(listerr, "SIZE PREPOSTEROUSLY LARGE"); return (0); }
        /*
         * Compute block size that the filesystem is based on,
         * according to FFS_FSBTODB, and adjust superblock block number
         * so we can tell if this is an alternate later.
         */
        super *= dev_bsize;
        dev_bsize = sblock->fs_fsize / FFS_FSBTODB(sblock, 1);
        sblk.b_bno = super / dev_bsize;
        sblk.b_size = SBLOCKSIZE;
        if (bflag)
                goto out;
        /*
         * Set all possible fields that could differ, then do check
         * of whole super block against an alternate super block->
         * When an alternate super-block is specified this check is skipped.
         */
        getblk(&asblk, cgsblock(sblock, sblock->fs_ncg - 1), sblock->fs_sbsize);
        if (asblk.b_errs)
                return (0);
        /* swap SB byte order if asked */
        if (doswap)
                ffs_sb_swap(asblk.b_un.b_fs, asblk.b_un.b_fs);

        memmove(altsblock, asblk.b_un.b_fs, sblock->fs_sbsize);
        if (needswap)
                ffs_sb_swap(asblk.b_un.b_fs, altsblock);
        if (altsblock->fs_magic == FS_UFS2EA_MAGIC) {
                altsblock->fs_magic = FS_UFS2_MAGIC;
        }
        /* change on-disk magic if asked */
        cvt_magic(asblk.b_un.b_fs);
        if (cmpsblks(sblock, altsblock)) {
                if (debug) {
                        uint32_t *nlp, *olp, *endlp;

                        printf("superblock mismatches\n");
                        nlp = (uint32_t *)altsblock;
                        olp = (uint32_t *)sblock;
                        endlp = olp + (sblock->fs_sbsize / sizeof *olp);
                        for ( ; olp < endlp; olp++, nlp++) {
                                if (*olp == *nlp)
                                        continue;
                                printf("offset %#x, original 0x%08x, alternate "
                                       "0x%08x\n",
                                    (int)((uint8_t *)olp-(uint8_t *)sblock),
                                    *olp, *nlp);
                        }
                }
                badsb(listerr,
                "VALUES IN SUPER BLOCK DISAGREE WITH THOSE IN FIRST ALTERNATE");
/*
                return (0);
*/
        }
out:

        sb_oldfscompat_read(sblock, &sblocksave);

        /* Now we know the SB is valid, we can write it back if needed */
        if (doswap || doing2ea || doing2noea) {
                sbdirty();
                dirty(&asblk);
        }
        havesb = 1;
        return (1);
}

int
cmpsblks(const struct fs *sb, struct fs *asb)
{
        if (!is_ufs2 && ((sb->fs_old_flags & FS_FLAGS_UPDATED) == 0)) {
                if (sb->fs_old_postblformat < FS_DYNAMICPOSTBLFMT)
                        return cmpsblks42(sb, asb);
                else
                        return cmpsblks44(sb, asb);
        }
        if (asb->fs_sblkno != sb->fs_sblkno ||
            asb->fs_cblkno != sb->fs_cblkno ||
            asb->fs_iblkno != sb->fs_iblkno ||
            asb->fs_dblkno != sb->fs_dblkno ||
            asb->fs_ncg != sb->fs_ncg ||
            asb->fs_bsize != sb->fs_bsize ||
            asb->fs_fsize != sb->fs_fsize ||
            asb->fs_frag != sb->fs_frag ||
            asb->fs_bmask != sb->fs_bmask ||
            asb->fs_fmask != sb->fs_fmask ||
            asb->fs_bshift != sb->fs_bshift ||
            asb->fs_fshift != sb->fs_fshift ||
            asb->fs_fragshift != sb->fs_fragshift ||
            asb->fs_fsbtodb != sb->fs_fsbtodb ||
            asb->fs_sbsize != sb->fs_sbsize ||
            asb->fs_nindir != sb->fs_nindir ||
            asb->fs_inopb != sb->fs_inopb ||
            asb->fs_cssize != sb->fs_cssize ||
            asb->fs_ipg != sb->fs_ipg ||
            asb->fs_fpg != sb->fs_fpg ||
            asb->fs_magic != sb->fs_magic)
                return 1;
        return 0;
}

/* BSD 4.2 performed the following superblock comparison
 * It should correspond to FS_42POSTBLFMT
 * (although note that in 4.2, the fs_old_postblformat
 * field didn't exist and the corresponding bits are
 * located near the end of the postbl itself, where they
 * are not likely to be used.)
 */
int
cmpsblks42(const struct fs *sb, struct fs *asb)
{
        asb->fs_firstfield = sb->fs_firstfield; /* fs_link */
        asb->fs_unused_1 = sb->fs_unused_1; /* fs_rlink */
        asb->fs_old_time = sb->fs_old_time; /* fs_time */
        asb->fs_old_cstotal = sb->fs_old_cstotal; /* fs_cstotal */
        asb->fs_cgrotor = sb->fs_cgrotor;
        asb->fs_fmod = sb->fs_fmod;
        asb->fs_clean = sb->fs_clean;
        asb->fs_ronly = sb->fs_ronly;
        asb->fs_old_flags = sb->fs_old_flags;
        asb->fs_maxcontig = sb->fs_maxcontig;
        asb->fs_minfree = sb->fs_minfree;
        asb->fs_old_rotdelay = sb->fs_old_rotdelay;
        asb->fs_maxbpg = sb->fs_maxbpg;

        /* The former fs_csp, totaling 128 bytes  */
        memmove(asb->fs_ocsp, sb->fs_ocsp, sizeof sb->fs_ocsp);
        asb->fs_contigdirs = sb->fs_contigdirs;
        asb->fs_csp = sb->fs_csp;
        asb->fs_maxcluster = sb->fs_maxcluster;
        asb->fs_active = sb->fs_active;

        /* The former fs_fsmnt, totaling 512 bytes */
        memmove(asb->fs_fsmnt, sb->fs_fsmnt, sizeof sb->fs_fsmnt);
        memmove(asb->fs_volname, sb->fs_volname, sizeof sb->fs_volname);

        return memcmp(sb, asb, sb->fs_sbsize);
}

/* BSD 4.4 performed the following superblock comparison
 * This was used in NetBSD through 1.6.1
 *
 * Note that this implementation is destructive to asb.
 */
int
cmpsblks44(const struct fs *sb, struct fs *asb)
{
        /*
         * "Copy fields which we don't care if they're different in the
         * alternate superblocks, as they're either likely to be
         * different because they're per-cylinder-group specific, or
         * because they're transient details which are only maintained
         * in the primary superblock."
         */
        asb->fs_firstfield = sb->fs_firstfield;
        asb->fs_unused_1 = sb->fs_unused_1;
        asb->fs_old_time = sb->fs_old_time;
        asb->fs_old_cstotal = sb->fs_old_cstotal;
        asb->fs_cgrotor = sb->fs_cgrotor;
        asb->fs_fmod = sb->fs_fmod;
        asb->fs_clean = sb->fs_clean;
        asb->fs_ronly = sb->fs_ronly;
        asb->fs_old_flags = sb->fs_old_flags;
        asb->fs_maxcontig = sb->fs_maxcontig;
        asb->fs_minfree = sb->fs_minfree;
        asb->fs_optim = sb->fs_optim;
        asb->fs_old_rotdelay = sb->fs_old_rotdelay;
        asb->fs_maxbpg = sb->fs_maxbpg;

        /* The former fs_csp and fs_maxcluster, totaling 128 bytes */
        memmove(asb->fs_ocsp, sb->fs_ocsp, sizeof sb->fs_ocsp);
        asb->fs_contigdirs = sb->fs_contigdirs;
        asb->fs_csp = sb->fs_csp;
        asb->fs_maxcluster = sb->fs_maxcluster;
        asb->fs_active = sb->fs_active;

        /* The former fs_fsmnt, totaling 512 bytes */
        memmove(asb->fs_fsmnt, sb->fs_fsmnt, sizeof sb->fs_fsmnt);
        memmove(asb->fs_volname, sb->fs_volname, sizeof sb->fs_volname);

        /* The former fs_sparecon, totaling 200 bytes */
        memmove(asb->fs_snapinum,
                sb->fs_snapinum, sizeof sb->fs_snapinum);
        asb->fs_avgfilesize = sb->fs_avgfilesize;
        asb->fs_avgfpdir = sb->fs_avgfpdir;
        asb->fs_save_cgsize = sb->fs_save_cgsize;
        memmove(asb->fs_sparecon32,
                sb->fs_sparecon32, sizeof sb->fs_sparecon32);
        asb->fs_flags = sb->fs_flags;

        /* Original comment:
         * "The following should not have to be copied, but need to be."
         */
        asb->fs_fsbtodb = sb->fs_fsbtodb;
        asb->fs_old_interleave = sb->fs_old_interleave;
        asb->fs_old_npsect = sb->fs_old_npsect;
        asb->fs_old_nrpos = sb->fs_old_nrpos;
        asb->fs_state = sb->fs_state;
        asb->fs_qbmask = sb->fs_qbmask;
        asb->fs_qfmask = sb->fs_qfmask;
        asb->fs_state = sb->fs_state;
        asb->fs_maxfilesize = sb->fs_maxfilesize;

        /*
         * "Compare the superblocks, effectively checking every other
         * field to see if they differ."
         */
        return memcmp(sb, asb, sb->fs_sbsize);
}

static void
badsb(int listerr, const char *s)
{

        if (!listerr)
                return;
        if (preen)
                printf("%s: ", cdevname());
        pfatal("BAD SUPER BLOCK: %s\n", s);
}

/*
 * Calculate a prototype superblock based on information in the disk label.
 * When done the cgsblock macro can be calculated and the fs_ncg field
 * can be used. Do NOT attempt to use other macros without verifying that
 * their needed information is available!
 */
static int
calcsb(const char *dev, int devfd, struct fs *fs)
{
        struct dkwedge_info dkw;
        struct disk_geom geo;
        int i, nspf;

        if (getdiskinfo(dev, fsreadfd, NULL, &geo, &dkw) == -1)
                pfatal("%s: CANNOT FIGURE OUT FILE SYSTEM PARTITION\n", dev);
        if (dkw.dkw_parent[0] == '\0') {
                pfatal("%s: CANNOT FIGURE OUT FILE SYSTEM PARTITION\n", dev);
                return (0);
        }
        if (strcmp(dkw.dkw_ptype, DKW_PTYPE_FFS)
#ifndef NO_APPLE_UFS
         && strcmp(dkw.dkw_ptype, DKW_PTYPE_APPLEUFS)
#endif
        ) {
                pfatal("%s: NOT LABELED AS A BSD FILE SYSTEM (%s)\n",
                    dev, dkw.dkw_ptype);
                return (0);
        }
        if (geo.dg_secsize == 0) {
                pfatal("%s: CANNOT FIGURE OUT SECTOR SIZE\n", dev);
                return 0;
        }
        if (geo.dg_secpercyl == 0) {
                pfatal("%s: CANNOT FIGURE OUT SECTORS PER CYLINDER\n", dev);
                return 0;
        }
        if (sblk.b_un.b_fs->fs_fsize == 0) {
                pfatal("%s: CANNOT FIGURE OUT FRAG BLOCK SIZE\n", dev);
                return 0;
        }
        if (sblk.b_un.b_fs->fs_fpg == 0) {
                pfatal("%s: CANNOT FIGURE OUT FRAGS PER GROUP\n", dev);
                return 0;
        }
        if (sblk.b_un.b_fs->fs_old_cpg == 0) {
                pfatal("%s: CANNOT FIGURE OUT OLD CYLINDERS PER GROUP\n", dev);
                return 0;
        }
        memcpy(fs, sblk.b_un.b_fs, sizeof(struct fs));
        nspf = fs->fs_fsize / geo.dg_secsize;
        fs->fs_old_nspf = nspf;
        for (fs->fs_fsbtodb = 0, i = nspf; i > 1; i >>= 1)
                fs->fs_fsbtodb++;
        dev_bsize = geo.dg_secsize;
        if (fs->fs_magic == FS_UFS2_MAGIC) {
                fs->fs_ncg = howmany(fs->fs_size, fs->fs_fpg);
        } else /* if (fs->fs_magic == FS_UFS1_MAGIC) */ {
                fs->fs_old_cgmask = 0xffffffff;
                for (i = geo.dg_ntracks; i > 1; i >>= 1)
                        fs->fs_old_cgmask <<= 1;
                if (!POWEROF2(geo.dg_ntracks))
                        fs->fs_old_cgmask <<= 1;
                fs->fs_old_cgoffset = roundup(
                        howmany(geo.dg_nsectors, nspf), fs->fs_frag);
                fs->fs_fpg = (fs->fs_old_cpg * geo.dg_secpercyl) / nspf;
                fs->fs_ncg = howmany(fs->fs_size / geo.dg_secpercyl,
                    fs->fs_old_cpg);
        }
        return (1);
}

/*
 * Test the list of snapshot inode numbers for duplicates and repair.
 */
static int
check_snapinum(void)
{
        int loc, loc2, res;
        uint32_t *snapinum = &sblock->fs_snapinum[0];

        res = 0;

        if (isappleufs)
                return 0;

        for (loc = 0; loc < FSMAXSNAP; loc++) {
                if (snapinum[loc] == 0)
                        break;
                for (loc2 = loc + 1; loc2 < FSMAXSNAP; loc2++) {
                        if (snapinum[loc2] == 0 ||
                            snapinum[loc2] == snapinum[loc])
                                break;
                }
                if (loc2 >= FSMAXSNAP || snapinum[loc2] == 0)
                        continue;
                pwarn("SNAPSHOT INODE %u ALREADY ON LIST%s", snapinum[loc2],
                    (res ? "" : "\n"));
                res = 1;
                for (loc2 = loc + 1; loc2 < FSMAXSNAP; loc2++) {
                        if (snapinum[loc2] == 0)
                                break;
                        snapinum[loc2 - 1] = snapinum[loc2];
                }
                snapinum[loc2 - 1] = 0;
                loc--;
        }

        return res;
}