/*      $OpenBSD: traverse.c,v 1.43 2024/09/15 07:14:58 jsg Exp $       */
/*      $NetBSD: traverse.c,v 1.17 1997/06/05 11:13:27 lukem Exp $      */

/*-
 * Copyright (c) 1980, 1988, 1991, 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/param.h>  /* MAXBSIZE DEV_BSIZE dbtob */
#include <sys/time.h>
#include <sys/stat.h>
#include <sys/disklabel.h>
#include <ufs/ffs/fs.h>
#include <ufs/ufs/dir.h>
#include <ufs/ufs/dinode.h>

#include <protocols/dumprestore.h>

#include <ctype.h>
#include <errno.h>
#include <fts.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <limits.h>

#include "dump.h"

extern struct disklabel lab;

union dinode {
        struct ufs1_dinode dp1;
        struct ufs2_dinode dp2;
};
#define DIP(dp, field) \
        ((sblock->fs_magic == FS_UFS1_MAGIC) ? \
        (dp)->dp1.field : (dp)->dp2.field)

#define HASDUMPEDFILE   0x1
#define HASSUBDIRS      0x2

static  int dirindir(ino_t, daddr_t, int, off_t *, int64_t *, int);
static  void dmpindir(ino_t, daddr_t, int, off_t *);
static  int searchdir(ino_t, daddr_t, long, off_t, int64_t *, int);
void    fs_mapinodes(ino_t maxino, off_t *tapesize, int *anydirskipped);

/*
 * This is an estimation of the number of TP_BSIZE blocks in the file.
 * It estimates the number of blocks in files with holes by assuming
 * that all of the blocks accounted for by di_blocks are data blocks
 * (when some of the blocks are usually used for indirect pointers);
 * hence the estimate may be high.
 */
int64_t
blockest(union dinode *dp)
{
        int64_t blkest, sizeest;

        /*
         * dp->di_size is the size of the file in bytes.
         * dp->di_blocks stores the number of sectors actually in the file.
         * If there are more sectors than the size would indicate, this just
         *      means that there are indirect blocks in the file or unused
         *      sectors in the last file block; we can safely ignore these
         *      (blkest = sizeest below).
         * If the file is bigger than the number of sectors would indicate,
         *      then the file has holes in it.  In this case we must use the
         *      block count to estimate the number of data blocks used, but
         *      we use the actual size for estimating the number of indirect
         *      dump blocks (sizeest vs. blkest in the indirect block
         *      calculation).
         */
        blkest = howmany(dbtob((int64_t)DIP(dp, di_blocks)), TP_BSIZE);
        sizeest = howmany((int64_t)DIP(dp, di_size), TP_BSIZE);
        if (blkest > sizeest)
                blkest = sizeest;
        if (DIP(dp, di_size) > sblock->fs_bsize * NDADDR) {
                /* calculate the number of indirect blocks on the dump tape */
                blkest +=
                        howmany(sizeest - NDADDR * sblock->fs_bsize / TP_BSIZE,
                        TP_NINDIR);
        }
        return (blkest + 1);
}

/* true if "nodump" flag has no effect here, i.e. dumping allowed */
#define CHECKNODUMP(dp) \
        (nonodump || (DIP((dp), di_flags) & UF_NODUMP) != UF_NODUMP)

/*
 * Determine if given inode should be dumped
 */
void
mapfileino(ino_t ino, int64_t *tapesize, int *dirskipped)
{
        int mode;
        union dinode *dp;

        dp = getino(ino, &mode);
        if (mode == 0)
                return;
        SETINO(ino, usedinomap);
        if (mode == IFDIR)
                SETINO(ino, dumpdirmap);
        if (CHECKNODUMP(dp) &&
            (DIP(dp, di_mtime) >= spcl.c_ddate ||
             DIP(dp, di_ctime) >= spcl.c_ddate)) {
                SETINO(ino, dumpinomap);
                if (mode != IFREG && mode != IFDIR && mode != IFLNK)
                        *tapesize += 1;
                else
                        *tapesize += blockest(dp);
                return;
        }
        if (mode == IFDIR) {
                if (!CHECKNODUMP(dp))
                        CLRINO(ino, usedinomap);
                *dirskipped = 1;
        }
}

void
fs_mapinodes(ino_t maxino, int64_t *tapesize, int *anydirskipped)
{
        int i, cg, inosused;
        struct cg *cgp;
        ino_t ino;

        if ((cgp = malloc(sblock->fs_cgsize)) == NULL)
                quit("fs_mapinodes: cannot allocate memory.\n");

        for (cg = 0; cg < sblock->fs_ncg; cg++) {
                ino = cg * (ino_t)sblock->fs_ipg;
                bread(fsbtodb(sblock, cgtod(sblock, cg)), (char *)cgp,
                    sblock->fs_cgsize);
                if (sblock->fs_magic == FS_UFS2_MAGIC)
                        inosused = cgp->cg_initediblk;
                else
                        inosused = sblock->fs_ipg;
                for (i = 0; i < inosused; i++, ino++) {
                        if (ino < ROOTINO)
                                continue;
                        mapfileino(ino, tapesize, anydirskipped);
                }
        }

        free(cgp);
}

/*
 * Dump pass 1.
 *
 * Walk the inode list for a filesystem to find all allocated inodes
 * that have been modified since the previous dump time. Also, find all
 * the directories in the filesystem.
 */
int
mapfiles(ino_t maxino, int64_t *tapesize, char *disk, char * const *dirv)
{
        int anydirskipped = 0;

        if (dirv != NULL) {
                char     curdir[PATH_MAX];
                FTS     *dirh;
                FTSENT  *entry;
                int      d;

                if (getcwd(curdir, sizeof(curdir)) == NULL) {
                        msg("Can't determine cwd: %s\n", strerror(errno));
                        dumpabort(0);
                }
                if ((dirh = fts_open(dirv, FTS_PHYSICAL|FTS_SEEDOT|FTS_XDEV,
                    NULL)) == NULL) {
                        msg("fts_open failed: %s\n", strerror(errno));
                        dumpabort(0);
                }
                while ((entry = fts_read(dirh)) != NULL) {
                        switch (entry->fts_info) {
                        case FTS_DNR:           /* an error */
                        case FTS_ERR:
                        case FTS_NS:
                                msg("Can't fts_read %s: %s\n", entry->fts_path,
                                    strerror(errno));
                                /* FALLTHROUGH */
                        case FTS_DP:            /* already seen dir */
                                continue;
                        }
                        mapfileino(entry->fts_statp->st_ino, tapesize,
                            &anydirskipped);
                }
                if (errno) {
                        msg("fts_read failed: %s\n", strerror(errno));
                        dumpabort(0);
                }
                (void)fts_close(dirh);

                /*
                 * Add any parent directories
                 */
                for (d = 0 ; dirv[d] != NULL ; d++) {
                        char path[PATH_MAX];

                        if (dirv[d][0] != '/')
                                (void)snprintf(path, sizeof(path), "%s/%s",
                                    curdir, dirv[d]);
                        else
                                (void)snprintf(path, sizeof(path), "%s",
                                    dirv[d]);
                        while (strcmp(path, disk) != 0) {
                                char *p;
                                struct stat sb;

                                if (*path == '\0')
                                        break;
                                if ((p = strrchr(path, '/')) == NULL)
                                        break;
                                if (p == path)
                                        break;
                                *p = '\0';
                                if (stat(path, &sb) == -1) {
                                        msg("Can't stat %s: %s\n", path,
                                            strerror(errno));
                                        break;
                                }
                                mapfileino(sb.st_ino, tapesize, &anydirskipped);
                        }
                }

                /*
                 * Ensure that the root inode actually appears in the
                 * file list for a subdir
                 */
                mapfileino(ROOTINO, tapesize, &anydirskipped);
        } else {
                fs_mapinodes(maxino, tapesize, &anydirskipped);
        }
        /*
         * Restore gets very upset if the root is not dumped,
         * so ensure that it always is dumped.
         */
        SETINO(ROOTINO, dumpinomap);
        return (anydirskipped);
}

/*
 * Dump pass 2.
 *
 * Scan each directory on the filesystem to see if it has any modified
 * files in it. If it does, and has not already been added to the dump
 * list (because it was itself modified), then add it. If a directory
 * has not been modified itself, contains no modified files and has no
 * subdirectories, then it can be deleted from the dump list and from
 * the list of directories. By deleting it from the list of directories,
 * its parent may now qualify for the same treatment on this or a later
 * pass using this algorithm.
 */
int
mapdirs(ino_t maxino, int64_t *tapesize)
{
        union dinode *dp;
        int i, isdir, nodump;
        char *map;
        ino_t ino;
        union dinode di;
        off_t filesize;
        int ret, change = 0;

        isdir = 0;              /* XXX just to get gcc to shut up */
        for (map = dumpdirmap, ino = 1; ino < maxino; ino++) {
                if (((ino - 1) % NBBY) == 0)    /* map is offset by 1 */
                        isdir = *map++;
                else
                        isdir >>= 1;
                /*
                 * If a directory has been removed from usedinomap, it
                 * either has the nodump flag set, or has inherited
                 * it.  Although a directory can't be in dumpinomap if
                 * it isn't in usedinomap, we have to go through it to
                 * propagate the nodump flag.
                 */
                nodump = !nonodump && !TSTINO(ino, usedinomap);
                if ((isdir & 1) == 0 || (TSTINO(ino, dumpinomap) && !nodump))
                        continue;
                dp = getino(ino, &i);
                /*
                 * inode buf may change in searchdir().
                 */
                if (sblock->fs_magic == FS_UFS1_MAGIC)
                        di.dp1 = dp->dp1;
                else
                        di.dp2 = dp->dp2;
                filesize = (off_t)DIP(dp, di_size);
                for (ret = 0, i = 0; filesize > 0 && i < NDADDR; i++) {
                        if (DIP(&di, di_db[i]) != 0)
                                ret |= searchdir(ino, DIP(&di, di_db[i]),
                                    sblksize(sblock, DIP(dp, di_size), i),
                                    filesize, tapesize, nodump);
                        if (ret & HASDUMPEDFILE)
                                filesize = 0;
                        else
                                filesize -= sblock->fs_bsize;
                }
                for (i = 0; filesize > 0 && i < NIADDR; i++) {
                        if (DIP(&di, di_ib[i]) == 0)
                                continue;
                        ret |= dirindir(ino, DIP(&di, di_ib[i]), i, &filesize,
                            tapesize, nodump);
                }
                if (ret & HASDUMPEDFILE) {
                        SETINO(ino, dumpinomap);
                        *tapesize += blockest(dp);
                        change = 1;
                        continue;
                }
                if (nodump) {
                        if (ret & HASSUBDIRS)
                                change = 1;     /* subdirs inherit nodump */
                        CLRINO(ino, dumpdirmap);
                } else if ((ret & HASSUBDIRS) == 0) {
                        if (!TSTINO(ino, dumpinomap)) {
                                CLRINO(ino, dumpdirmap);
                                change = 1;
                        }
                }
        }
        return (change);
}

/*
 * Read indirect blocks, and pass the data blocks to be searched
 * as directories. Quit as soon as any entry is found that will
 * require the directory to be dumped.
 */
static int
dirindir(ino_t ino, daddr_t blkno, int ind_level, off_t *filesize,
    int64_t *tapesize, int nodump)
{
        int ret = 0;
        int i;
        char idblk[MAXBSIZE];

        bread(fsbtodb(sblock, blkno), idblk, (int)sblock->fs_bsize);
        if (ind_level <= 0) {
                for (i = 0; *filesize > 0 && i < NINDIR(sblock); i++) {
                        if (sblock->fs_magic == FS_UFS1_MAGIC)
                                blkno = ((int32_t *)idblk)[i];
                        else
                                blkno = ((int64_t *)idblk)[i];
                        if (blkno != 0)
                                ret |= searchdir(ino, blkno, sblock->fs_bsize,
                                        *filesize, tapesize, nodump);
                        if (ret & HASDUMPEDFILE)
                                *filesize = 0;
                        else
                                *filesize -= sblock->fs_bsize;
                }
                return (ret);
        }
        ind_level--;
        for (i = 0; *filesize > 0 && i < NINDIR(sblock); i++) {
                if (sblock->fs_magic == FS_UFS1_MAGIC)
                        blkno = ((int32_t *)idblk)[i];
                else
                        blkno = ((int64_t *)idblk)[i];
                if (blkno != 0)
                        ret |= dirindir(ino, blkno, ind_level, filesize,
                            tapesize, nodump);
        }
        return (ret);
}

/*
 * Scan a disk block containing directory information looking to see if
 * any of the entries are on the dump list and to see if the directory
 * contains any subdirectories.
 */
static int
searchdir(ino_t ino, daddr_t blkno, long size, off_t filesize,
    int64_t *tapesize, int nodump)
{
        struct direct *dp;
        union dinode *ip;
        long loc;
        static caddr_t dblk;
        int mode, ret = 0;

        if (dblk == NULL && (dblk = malloc(sblock->fs_bsize)) == NULL)
                quit("searchdir: cannot allocate indirect memory.\n");
        bread(fsbtodb(sblock, blkno), dblk, (int)size);
        if (filesize < size)
                size = filesize;
        for (loc = 0; loc < size; ) {
                dp = (struct direct *)(dblk + loc);
                if (dp->d_reclen == 0) {
                        msg("corrupted directory, inumber %llu\n",
                            (unsigned long long)ino);
                        break;
                }
                loc += dp->d_reclen;
                if (dp->d_ino == 0)
                        continue;
                if (dp->d_name[0] == '.') {
                        if (dp->d_name[1] == '\0')
                                continue;
                        if (dp->d_name[1] == '.' && dp->d_name[2] == '\0')
                                continue;
                }
                if (nodump) {
                        ip = getino(dp->d_ino, &mode);
                        if (TSTINO(dp->d_ino, dumpinomap)) {
                                CLRINO(dp->d_ino, dumpinomap);
                                *tapesize -= blockest(ip);
                        }
                        /*
                         * Add back to dumpdirmap and remove from usedinomap
                         * to propagate nodump.
                         */
                        if (mode == IFDIR) {
                                SETINO(dp->d_ino, dumpdirmap);
                                CLRINO(dp->d_ino, usedinomap);
                                ret |= HASSUBDIRS;
                        }
                } else {
                        if (TSTINO(dp->d_ino, dumpinomap)) {
                                ret |= HASDUMPEDFILE;
                                if (ret & HASSUBDIRS)
                                        break;
                        }
                        if (TSTINO(dp->d_ino, dumpdirmap)) {
                                ret |= HASSUBDIRS;
                                if (ret & HASDUMPEDFILE)
                                        break;
                        }
                }
        }
        return (ret);
}

/*
 * Dump passes 3 and 4.
 *
 * Dump the contents of an inode to tape.
 */
void
dumpino(union dinode *dp, ino_t ino)
{
        int ind_level, cnt;
        off_t size;
        char buf[TP_BSIZE];

        if (newtape) {
                newtape = 0;
                dumpmap(dumpinomap, TS_BITS, ino);
        }
        CLRINO(ino, dumpinomap);
        if (sblock->fs_magic == FS_UFS1_MAGIC) {
                spcl.c_mode = dp->dp1.di_mode;
                spcl.c_size = dp->dp1.di_size;
                spcl.c_old_atime = (time_t)dp->dp1.di_atime;
                spcl.c_atime = dp->dp1.di_atime;
                spcl.c_atimensec = dp->dp1.di_atimensec;
                spcl.c_old_mtime = (time_t)dp->dp1.di_mtime;
                spcl.c_mtime = dp->dp1.di_mtime;
                spcl.c_mtimensec = dp->dp1.di_mtimensec;
                spcl.c_birthtime = 0;
                spcl.c_birthtimensec = 0;
                spcl.c_rdev = dp->dp1.di_rdev;
                spcl.c_file_flags = dp->dp1.di_flags;
                spcl.c_uid = dp->dp1.di_uid;
                spcl.c_gid = dp->dp1.di_gid;
        } else {
                spcl.c_mode = dp->dp2.di_mode;
                spcl.c_size = dp->dp2.di_size;
                spcl.c_atime = dp->dp2.di_atime;
                spcl.c_atimensec = dp->dp2.di_atimensec;
                spcl.c_mtime = dp->dp2.di_mtime;
                spcl.c_mtimensec = dp->dp2.di_mtimensec;
                spcl.c_birthtime = dp->dp2.di_birthtime;
                spcl.c_birthtimensec = dp->dp2.di_birthnsec;
                spcl.c_rdev = dp->dp2.di_rdev;
                spcl.c_file_flags = dp->dp2.di_flags;
                spcl.c_uid = dp->dp2.di_uid;
                spcl.c_gid = dp->dp2.di_gid;
        }
        spcl.c_type = TS_INODE;
        spcl.c_count = 0;
        switch (DIP(dp, di_mode) & S_IFMT) {

        case 0:
                /*
                 * Freed inode.
                 */
                return;

        case IFLNK:
                /*
                 * Check for short symbolic link.
                 */
                if (DIP(dp, di_size) > 0 &&
                    DIP(dp, di_size) < sblock->fs_maxsymlinklen) {
                        void *shortlink;

                        spcl.c_addr[0] = 1;
                        spcl.c_count = 1;
                        writeheader(ino);
                        if (sblock->fs_magic == FS_UFS1_MAGIC)
                                shortlink = dp->dp1.di_shortlink;
                        else
                                shortlink = dp->dp2.di_shortlink;
                        memcpy(buf, shortlink, DIP(dp, di_size));
                        buf[DIP(dp, di_size)] = '\0';
                        writerec(buf, 0);
                        return;
                }
                /* FALLTHROUGH */

        case IFDIR:
        case IFREG:
                if (DIP(dp, di_size) > 0)
                        break;
                /* FALLTHROUGH */

        case IFIFO:
        case IFSOCK:
        case IFCHR:
        case IFBLK:
                writeheader(ino);
                return;

        default:
                msg("Warning: undefined file type 0%o\n",
                    DIP(dp, di_mode) & IFMT);
                return;
        }
        if (DIP(dp, di_size) > NDADDR * sblock->fs_bsize)
                cnt = NDADDR * sblock->fs_frag;
        else
                cnt = howmany(DIP(dp, di_size), sblock->fs_fsize);
        if (sblock->fs_magic == FS_UFS1_MAGIC)
                ufs1_blksout(&dp->dp1.di_db[0], cnt, ino);
        else
                ufs2_blksout(&dp->dp2.di_db[0], cnt, ino);
        if ((size = DIP(dp, di_size) - NDADDR * sblock->fs_bsize) <= 0)
                return;
        for (ind_level = 0; ind_level < NIADDR; ind_level++) {
                dmpindir(ino, DIP(dp, di_ib[ind_level]), ind_level, &size);
                if (size <= 0)
                        return;
        }
}

/*
 * Read indirect blocks, and pass the data blocks to be dumped.
 */
static void
dmpindir(ino_t ino, daddr_t  blk, int ind_level, off_t *size)
{
        int i, cnt;
        char idblk[MAXBSIZE];

        if (blk != 0)
                bread(fsbtodb(sblock, blk), idblk, (int) sblock->fs_bsize);
        else
                memset(idblk, 0, (int)sblock->fs_bsize);
        if (ind_level <= 0) {
                if (*size < NINDIR(sblock) * sblock->fs_bsize)
                        cnt = howmany(*size, sblock->fs_fsize);
                else
                        cnt = NINDIR(sblock) * sblock->fs_frag;
                *size -= NINDIR(sblock) * sblock->fs_bsize;
                if (sblock->fs_magic == FS_UFS1_MAGIC)
                        ufs1_blksout((int32_t *)idblk, cnt, ino);
                else
                        ufs2_blksout((int64_t *)idblk, cnt, ino);
                return;
        }
        ind_level--;
        for (i = 0; i < NINDIR(sblock); i++) {
                if (sblock->fs_magic == FS_UFS1_MAGIC)
                        dmpindir(ino, ((int32_t *)idblk)[i], ind_level,
                            size);
                else
                        dmpindir(ino, ((int64_t *)idblk)[i], ind_level,
                            size);
                if (*size <= 0)
                        return;
        }
}

/*
 * Collect up the data into tape record sized buffers and output them.
 */
void
ufs1_blksout(int32_t *blkp, int frags, ino_t ino)
{
        int32_t *bp;
        int i, j, count, blks, tbperdb;

        blks = howmany(frags * sblock->fs_fsize, TP_BSIZE);
        tbperdb = sblock->fs_bsize >> tp_bshift;
        for (i = 0; i < blks; i += TP_NINDIR) {
                if (i + TP_NINDIR > blks)
                        count = blks;
                else
                        count = i + TP_NINDIR;
                for (j = i; j < count; j++)
                        if (blkp[j / tbperdb] != 0)
                                spcl.c_addr[j - i] = 1;
                        else
                                spcl.c_addr[j - i] = 0;
                spcl.c_count = count - i;
                writeheader(ino);
                bp = &blkp[i / tbperdb];
                for (j = i; j < count; j += tbperdb, bp++)
                        if (*bp != 0) {
                                if (j + tbperdb <= count)
                                        dumpblock(*bp, (int)sblock->fs_bsize);
                                else
                                        dumpblock(*bp, (count - j) * TP_BSIZE);
                        }
                spcl.c_type = TS_ADDR;
        }
}

/*
 * Collect up the data into tape record sized buffers and output them.
 */
void
ufs2_blksout(daddr_t *blkp, int frags, ino_t ino)
{
        daddr_t *bp;
        int i, j, count, blks, tbperdb;

        blks = howmany(frags * sblock->fs_fsize, TP_BSIZE);
        tbperdb = sblock->fs_bsize >> tp_bshift;
        for (i = 0; i < blks; i += TP_NINDIR) {
                if (i + TP_NINDIR > blks)
                        count = blks;
                else
                        count = i + TP_NINDIR;
                for (j = i; j < count; j++)
                        if (blkp[j / tbperdb] != 0)
                                spcl.c_addr[j - i] = 1;
                        else
                                spcl.c_addr[j - i] = 0;
                spcl.c_count = count - i;
                writeheader(ino);
                bp = &blkp[i / tbperdb];
                for (j = i; j < count; j += tbperdb, bp++)
                        if (*bp != 0) {
                                if (j + tbperdb <= count)
                                        dumpblock(*bp, (int)sblock->fs_bsize);
                                else
                                        dumpblock(*bp, (count - j) * TP_BSIZE);
                        }
                spcl.c_type = TS_ADDR;
        }
}

/*
 * Dump a map to the tape.
 */
void
dumpmap(char *map, int type, ino_t ino)
{
        int i;
        char *cp;

        spcl.c_type = type;
        spcl.c_count = howmany(mapsize * sizeof(char), TP_BSIZE);
        writeheader(ino);
        for (i = 0, cp = map; i < spcl.c_count; i++, cp += TP_BSIZE)
                writerec(cp, 0);
}

/*
 * Write a header record to the dump tape.
 */
void
writeheader(ino_t ino)
{
        int32_t sum, cnt, *lp;

        spcl.c_inumber = ino;
        if (sblock->fs_magic == FS_UFS2_MAGIC) {
                spcl.c_magic = FS_UFS2_MAGIC;
        } else {
                spcl.c_magic = NFS_MAGIC;
                spcl.c_old_date = (int32_t)spcl.c_date;
                spcl.c_old_ddate = (int32_t)spcl.c_ddate;
                spcl.c_old_tapea = (int32_t)spcl.c_tapea;
                spcl.c_old_firstrec = (int32_t)spcl.c_firstrec;
        }
        spcl.c_checksum = 0;
        lp = (int32_t *)&spcl;
        sum = 0;
        cnt = sizeof(union u_spcl) / (4 * sizeof(int32_t));
        while (--cnt >= 0) {
                sum += *lp++;
                sum += *lp++;
                sum += *lp++;
                sum += *lp++;
        }
        spcl.c_checksum = CHECKSUM - sum;
        writerec((char *)&spcl, 1);
}

union dinode *
getino(ino_t inum, int *modep)
{
        static ino_t minino, maxino;
        static void *inoblock;
        struct ufs1_dinode *dp1;
        struct ufs2_dinode *dp2;

        if (inoblock == NULL && (inoblock = malloc(sblock->fs_bsize)) == NULL)
                quit("cannot allocate inode memory.\n");
        curino = inum;
        if (inum >= minino && inum < maxino)
                goto gotit;
        bread(fsbtodb(sblock, ino_to_fsba(sblock, inum)), inoblock,
            (int)sblock->fs_bsize);
        minino = inum - (inum % INOPB(sblock));
        maxino = minino + INOPB(sblock);
gotit:
        if (sblock->fs_magic == FS_UFS1_MAGIC) {
                dp1 = &((struct ufs1_dinode *)inoblock)[inum - minino];
                *modep = (dp1->di_mode & IFMT);
                return ((union dinode *)dp1);
        }
        dp2 = &((struct ufs2_dinode *)inoblock)[inum - minino];
        *modep = (dp2->di_mode & IFMT);
        return ((union dinode *)dp2);
}

/*
 * Read a chunk of data from the disk.
 * Try to recover from hard errors by reading in sector sized pieces.
 * Error recovery is attempted at most BREADEMAX times before seeking
 * consent from the operator to continue.
 */
int     breaderrors = 0;
#define BREADEMAX 32

void
bread(daddr_t blkno, char *buf, int size)
{
        static char *mybuf = NULL;
        char *mybufp, *bufp, *np;
        static size_t mybufsz = 0;
        off_t offset;
        int cnt, i;
        u_int64_t secno, seccount;
        u_int32_t secoff, secsize = lab.d_secsize;

        /*
         * We must read an integral number of sectors large enough to contain
         * all the requested data. The read must begin at a sector.
         */
        if (DL_BLKOFFSET(&lab, blkno) == 0 && size % secsize == 0) {
                secno = DL_BLKTOSEC(&lab, blkno);
                secoff = 0;
                seccount = size / secsize;
                bufp = buf;
        } else {
                secno = DL_BLKTOSEC(&lab, blkno);
                secoff = DL_BLKOFFSET(&lab, blkno);
                seccount = DL_BLKTOSEC(&lab, (size + secoff) / DEV_BSIZE);
                if (seccount * secsize < (size + secoff))
                        seccount++;
                if (mybufsz < seccount * secsize) {
                        np = reallocarray(mybuf, seccount, secsize);
                        if (np == NULL) {
                                msg("No memory to read %llu %u-byte sectors",
                                    seccount, secsize);
                                dumpabort(0);
                        }
                        mybufsz = seccount * secsize;
                        mybuf = np;
                }
                bufp = mybuf;
        }

        offset = secno * secsize;

loop:
        if ((cnt = pread(diskfd, bufp, seccount * secsize, offset)) ==
            seccount * secsize)
                goto done;
        if (blkno + (size / DEV_BSIZE) >
            fsbtodb(sblock, sblock->fs_ffs1_size)) {
                /*
                 * Trying to read the final fragment.
                 *
                 * NB - dump only works in TP_BSIZE blocks, hence
                 * rounds `DEV_BSIZE' fragments up to TP_BSIZE pieces.
                 * It should be smarter about not actually trying to
                 * read more than it can get, but for the time being
                 * we punt and scale back the read only when it gets
                 * us into trouble. (mkm 9/25/83)
                 */
                size -= secsize;
                seccount--;
                goto loop;
        }
        if (cnt == -1)
                msg("read error from %s: %s: [block %lld]: count=%d\n",
                    disk, strerror(errno), (long long)blkno, size);
        else
                msg("short read error from %s: [block %lld]: count=%d, "
                    "got=%d\n", disk, (long long)blkno, size, cnt);
        if (++breaderrors > BREADEMAX) {
                msg("More than %d block read errors from %s\n",
                        BREADEMAX, disk);
                broadcast("DUMP IS AILING!\n");
                msg("This is an unrecoverable error.\n");
                if (!query("Do you want to attempt to continue?")){
                        dumpabort(0);
                        /*NOTREACHED*/
                } else
                        breaderrors = 0;
        }
        /*
         * Zero buffer, then try to read each sector of buffer separately.
         */
        if (bufp == mybuf)
                memset(bufp, 0, mybufsz);
        else
                memset(bufp, 0, size);
        for (i = 0, mybufp = bufp; i < size; i += secsize, mybufp += secsize) {
                if ((cnt = pread(diskfd, mybufp, secsize, offset + i)) ==
                    secsize)
                        continue;
                if (cnt == -1) {
                        msg("read error from %s: %s: [block %lld]: "
                            "count=%u\n", disk, strerror(errno),
                            (long long)(offset + i) / DEV_BSIZE, secsize);
                        continue;
                }
                msg("short read error from %s: [block %lld]: count=%u, "
                    "got=%d\n", disk, (long long)(offset + i) / DEV_BSIZE,
                    secsize, cnt);
        }

done:
        /* If necessary, copy out data that was read. */
        if (bufp == mybuf)
                memcpy(buf, bufp + secoff, size);
}