Another set of cleanups from Andreas Dilger (time_t cleanups, libext2 version etc).

[dump.git] / restore / tape.c

/*
 *      Ported to Linux's Second Extended File System as part of the
 *      dump and restore backup suit
 *      Remy Card <card@Linux.EU.Org>, 1994-1997
 *      Stelian Pop <pop@noos.fr>, 1999-2000
 *      Stelian Pop <pop@noos.fr> - Alcôve <www.alcove.fr>, 2000
 */

/*
 * Copyright (c) 1983, 1993
 *      The Regents of the University of California.  All rights reserved.
 * (c) UNIX System Laboratories, Inc.
 * All or some portions of this file are derived from material licensed
 * to the University of California by American Telephone and Telegraph
 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
 * the permission of UNIX System Laboratories, Inc.
 *
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. 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.
 */

#ifndef lint
static const char rcsid[] =
        "$Id: tape.c,v 1.28 2001/03/20 09:14:58 stelian Exp $";
#endif /* not lint */

#include <config.h>
#include <errno.h>
#include <compaterr.h>
#include <setjmp.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include <sys/param.h>
#include <sys/file.h>
#include <sys/mtio.h>
#include <sys/stat.h>

#ifdef  __linux__
#include <sys/time.h>
#include <time.h>
#include <linux/ext2_fs.h>
#include <ext2fs/ext2fs.h>
#include <bsdcompat.h>
#else   /* __linux__ */
#include <ufs/ufs/dinode.h>
#endif  /* __linux__ */
#include <protocols/dumprestore.h>

#ifdef HAVE_ZLIB
#include <zlib.h>
#endif /* HAVE_ZLIB */

#include "restore.h"
#include "extern.h"
#include "pathnames.h"

static long     fssize = MAXBSIZE;
static int      mt = -1;
static int      pipein = 0;
static int      magtapein = 0;          /* input is from magtape */
static char     magtape[MAXPATHLEN];
static char     magtapeprefix[MAXPATHLEN];
static int      blkcnt;
static int      numtrec;
static char     *tapebuf;               /* input buffer for read */
static int      bufsize;                /* buffer size without prefix */
static char     *tbufptr = NULL;        /* active tape buffer */
#ifdef HAVE_ZLIB
static char     *comprbuf;              /* uncompress work buf */
static size_t   comprlen;               /* size including prefix */
#endif
static union    u_spcl endoftapemark;
static long     blksread;               /* blocks read since last header */
static long     tpblksread = 0;         /* TP_BSIZE blocks read */
static long     tapesread;
static sigjmp_buf       restart;
static int      gettingfile = 0;        /* restart has a valid frame */
static char     *host = NULL;

static int      ofile;
static char     *map;
static char     lnkbuf[MAXPATHLEN + 1];
static int      pathlen;

int             oldinofmt;      /* old inode format conversion required */
int             Bcvt;           /* Swap Bytes (for CCI or sun) */
static int      Qcvt;           /* Swap quads (for sun) */

#define FLUSHTAPEBUF()  blkcnt = ntrec + 1

static void      accthdr __P((struct s_spcl *));
static int       checksum __P((int *));
static void      findinode __P((struct s_spcl *));
static void      findtapeblksize __P((void));
static int       gethead __P((struct s_spcl *));
static void      readtape __P((char *));
static void      setdumpnum __P((void));
static u_int     swabi __P((u_int));
#if 0
static u_long    swabl __P((u_long));
#endif
static u_char   *swab64 __P((u_char *, int));
static u_char   *swab32 __P((u_char *, int));
static u_char   *swab16 __P((u_char *, int));
static void      terminateinput __P((void));
static void      xtrfile __P((char *, size_t));
static void      xtrlnkfile __P((char *, size_t));
static void      xtrlnkskip __P((char *, size_t));
static void      xtrmap __P((char *, size_t));
static void      xtrmapskip __P((char *, size_t));
static void      xtrskip __P((char *, size_t));

#ifdef HAVE_ZLIB
static void     newcomprbuf __P((long));
static void     readtape_set __P((char *));
static void     readtape_uncompr __P((char *));
static void     readtape_comprfile __P((char *));
static void     readtape_comprtape __P((char *));
static char     *decompress_tapebuf __P((struct tapebuf *, int));
static void     msg_read_error __P((char *));
#endif
static int      read_a_block __P((int, void *, size_t, long *));
#define PREFIXSIZE      sizeof(struct tapebuf)

#define COMPARE_ONTHEFLY 1

#if COMPARE_ONTHEFLY
static int      ifile;          /* input file for compare */
static int      cmperror;       /* compare error */
static void     xtrcmpfile __P((char *, size_t));
static void     xtrcmpskip __P((char *, size_t));
#endif

static int readmapflag;

/*
 * Set up an input source. This is called from main.c before setup() is.
 */
void
setinput(char *source)
{
        FLUSHTAPEBUF();
        if (bflag)
                newtapebuf(ntrec);
        else
                newtapebuf(NTREC > HIGHDENSITYTREC ? NTREC : HIGHDENSITYTREC);
        terminal = stdin;

#ifdef RRESTORE
        if (strchr(source, ':')) {
                host = source;
                source = strchr(host, ':');
                *source++ = '\0';
                if (rmthost(host) == 0)
                        exit(1);
        } else
#endif
        if (strcmp(source, "-") == 0) {
                /*
                 * Since input is coming from a pipe we must establish
                 * our own connection to the terminal.
                 */
                terminal = fopen(_PATH_TTY, "r");
                if (terminal == NULL) {
                        warn("cannot open %s", _PATH_TTY);
                        terminal = fopen(_PATH_DEVNULL, "r");
                        if (terminal == NULL)
                                err(1, "cannot open %s", _PATH_DEVNULL);
                }
                pipein++;
        }
        setuid(getuid());       /* no longer need or want root privileges */
        if (Mflag) {
                strncpy(magtapeprefix, source, MAXPATHLEN);
                magtapeprefix[MAXPATHLEN-1] = '\0';
                snprintf(magtape, MAXPATHLEN, "%s%03d", source, 1);
        }
        else
                strncpy(magtape, source, MAXPATHLEN);
        magtape[MAXPATHLEN - 1] = '\0';
}

void
newtapebuf(long size)
{
        static int tapebufsize = -1;

        ntrec = size;
        bufsize = ntrec * TP_BSIZE;
        if (size <= tapebufsize)
                return;
        if (tapebuf != NULL)
                free(tapebuf);
        tapebuf = malloc(size * TP_BSIZE + sizeof(struct tapebuf));
        if (tapebuf == NULL)
                errx(1, "Cannot allocate space for tape buffer");
        tapebufsize = size;
}

#ifdef HAVE_ZLIB
static void
newcomprbuf(long size)
{
        if (size <= comprlen)
                return;
        comprlen = size + sizeof(struct tapebuf);
        if (comprbuf != NULL)
                free(comprbuf);
        comprbuf = malloc(comprlen);
        if (comprbuf == NULL)
                errx(1, "Cannot allocate space for decompress buffer");
}
#endif /* HAVE_ZLIB */

/*
 * Verify that the tape drive can be accessed and
 * that it actually is a dump tape.
 */
void
setup(void)
{
        int i, j, *ip;
        struct stat stbuf;
        struct mtget mt_stat;

        Vprintf(stdout, "Verify tape and initialize maps\n");
#ifdef RRESTORE
        if (host)
                mt = rmtopen(magtape, 0);
        else
#endif
        if (pipein)
                mt = 0;
        else
                mt = open(magtape, O_RDONLY, 0);
        if (mt < 0)
                err(1, "%s", magtape);
        volno = 1;
        if (!pipein) {
                /* need to know if input is really from a tape */
#ifdef RRESTORE
                if (host)
                        magtapein = rmtioctl(MTNOP, 1) != -1;
                else
#endif
                        magtapein = ioctl(mt, MTIOCGET, (char *) &mt_stat) == 0;
        }

        Vprintf(stdout,"Input is from %s\n", magtapein? "tape": "file/pipe");
        setdumpnum();
        FLUSHTAPEBUF();
        findtapeblksize();
        if (gethead(&spcl) == FAIL) {
                blkcnt--; /* push back this block */
                blksread--;
                tpblksread--;
                cvtflag++;
                if (gethead(&spcl) == FAIL)
                        errx(1, "Tape is not a dump tape");
                fprintf(stderr, "Converting to new file system format.\n");
        }

        if (zflag) {
                fprintf(stderr, "Dump tape is compressed.\n");
#ifdef HAVE_ZLIB
                newcomprbuf(bufsize);
#else
                errx(1,"This restore version doesn't support decompression");
#endif /* HAVE_ZLIB */
        }
        if (pipein) {
                endoftapemark.s_spcl.c_magic = cvtflag ? OFS_MAGIC : NFS_MAGIC;
                endoftapemark.s_spcl.c_type = TS_END;
                ip = (int *)&endoftapemark;
                j = sizeof(union u_spcl) / sizeof(int);
                i = 0;
                do
                        i += *ip++;
                while (--j);
                endoftapemark.s_spcl.c_checksum = CHECKSUM - i;
        }
        if (vflag || command == 't' || command == 'C')
                printdumpinfo();
        if (filesys[0] == '\0') {
                char *dirptr;
                strncpy(filesys, spcl.c_filesys, NAMELEN);
                filesys[NAMELEN - 1] = '\0';
                dirptr = strstr(filesys, " (dir");
                if (dirptr != NULL)
                        *dirptr = '\0';
        }
        dumptime = spcl.c_ddate;
        dumpdate = spcl.c_date;
        if (stat(".", &stbuf) < 0)
                err(1, "cannot stat .");
        if (stbuf.st_blksize > 0 && stbuf.st_blksize < TP_BSIZE )
                fssize = TP_BSIZE;
        if (stbuf.st_blksize >= TP_BSIZE && stbuf.st_blksize <= MAXBSIZE)
                fssize = stbuf.st_blksize;
        if (((fssize - 1) & fssize) != 0)
                errx(1, "bad block size %ld", fssize);
        if (spcl.c_volume != 1)
                errx(1, "Tape is not volume 1 of the dump");
        if (gethead(&spcl) == FAIL) {
                Dprintf(stdout, "header read failed at %ld blocks\n", (long)blksread);
                panic("no header after volume mark!\n");
        }
        findinode(&spcl);
        if (spcl.c_type != TS_CLRI)
                errx(1, "Cannot find file removal list");
        maxino = (spcl.c_count * TP_BSIZE * NBBY) + 1;
        Dprintf(stdout, "maxino = %ld\n", (long)maxino);
        map = calloc((unsigned)1, (unsigned)howmany(maxino, NBBY));
        if (map == NULL)
                errx(1, "no memory for active inode map");
        usedinomap = map;
        curfile.action = USING;
        getfile(xtrmap, xtrmapskip);
        if (spcl.c_type != TS_BITS)
                errx(1, "Cannot find file dump list");
        map = calloc((unsigned)1, (unsigned)howmany(maxino, NBBY));
        if (map == (char *)NULL)
                errx(1, "no memory for file dump list");
        dumpmap = map;
        curfile.action = USING;
        getfile(xtrmap, xtrmapskip);
        /*
         * If there may be whiteout entries on the tape, pretend that the
         * whiteout inode exists, so that the whiteout entries can be
         * extracted.
         */
        if (oldinofmt == 0)
                SETINO(WINO, dumpmap);
}

/*
 * Prompt user to load a new dump volume.
 * "Nextvol" is the next suggested volume to use.
 * This suggested volume is enforced when doing full
 * or incremental restores, but can be overridden by
 * the user when only extracting a subset of the files.
 */
void
getvol(long nextvol)
{
        long newvol = 0, savecnt = 0, wantnext = 0, i;
        union u_spcl tmpspcl;
#       define tmpbuf tmpspcl.s_spcl
        char buf[TP_BSIZE];
        int haderror = 0;

        if (nextvol == 1) {
                tapesread = 0;
                gettingfile = 0;
        }
        if (pipein) {
                if (nextvol != 1)
                        panic("Changing volumes on pipe input?\n");
                if (volno == 1)
                        return;
                goto gethdr;
        }
        savecnt = blksread;
again:
        if (pipein)
                exit(1); /* pipes do not get a second chance */
        if (command == 'R' || command == 'r' || curfile.action != SKIP) {
                newvol = nextvol;
                wantnext = 1;
        } else {
                newvol = 0;
                wantnext = 0;
        }
        while (newvol <= 0) {
                if (tapesread == 0) {
                        fprintf(stderr, "%s%s%s%s%s",
                            "You have not read any tapes yet.\n",
                            "Unless you know which volume your",
                            " file(s) are on you should start\n",
                            "with the last volume and work",
                            " towards the first.\n");
                } else {
                        fprintf(stderr, "You have read volumes");
                        strcpy(buf, ": ");
                        for (i = 1; i < 32; i++)
                                if (tapesread & (1 << i)) {
                                        fprintf(stderr, "%s%ld", buf, (long)i);
                                        strcpy(buf, ", ");
                                }
                        fprintf(stderr, "\n");
                }
                do      {
                        fprintf(stderr, "Specify next volume #: ");
                        (void) fflush(stderr);
                        (void) fgets(buf, TP_BSIZE, terminal);
                } while (!feof(terminal) && buf[0] == '\n');
                if (feof(terminal))
                        exit(1);
                newvol = atoi(buf);
                if (newvol <= 0) {
                        fprintf(stderr,
                            "Volume numbers are positive numerics\n");
                }
        }
        if (newvol == volno) {
                tapesread |= 1 << volno;
                return;
        }
        closemt();
        if (Mflag) {
                snprintf(magtape, MAXPATHLEN, "%s%03ld", magtapeprefix, newvol);
                magtape[MAXPATHLEN - 1] = '\0';
        }
        if (!Mflag || haderror) {
                haderror = 0;
                fprintf(stderr, "Mount tape volume %ld\n", (long)newvol);
                fprintf(stderr, "Enter ``none'' if there are no more tapes\n");
                fprintf(stderr, "otherwise enter tape name (default: %s) ", magtape);
                (void) fflush(stderr);
                (void) fgets(buf, TP_BSIZE, terminal);
                if (feof(terminal))
                        exit(1);
                if (!strcmp(buf, "none\n")) {
                        terminateinput();
                        return;
                }
                if (buf[0] != '\n') {
                        (void) strcpy(magtape, buf);
                        magtape[strlen(magtape) - 1] = '\0';
                }
        }
#ifdef RRESTORE
        if (host)
                mt = rmtopen(magtape, 0);
        else
#endif
                mt = open(magtape, O_RDONLY, 0);

        if (mt == -1) {
                fprintf(stderr, "Cannot open %s\n", magtape);
                volno = -1;
                haderror = 1;
                goto again;
        }
gethdr:
        volno = newvol;
        setdumpnum();
        FLUSHTAPEBUF();
        if (gethead(&tmpbuf) == FAIL) {
                Dprintf(stdout, "header read failed at %ld blocks\n", (long)blksread);
                fprintf(stderr, "tape is not dump tape\n");
                volno = 0;
                haderror = 1;
                goto again;
        }
        if (tmpbuf.c_volume != volno) {
                fprintf(stderr, "Wrong volume (%d)\n", tmpbuf.c_volume);
                volno = 0;
                haderror = 1;
                goto again;
        }
        if (tmpbuf.c_date != dumpdate || tmpbuf.c_ddate != dumptime) {
                fprintf(stderr, "Wrong dump date\n\tgot: %s",
                        ctime4(&tmpbuf.c_date));
                fprintf(stderr, "\twanted: %s", ctime(&dumpdate));
                volno = 0;
                haderror = 1;
                goto again;
        }
        tapesread |= 1 << volno;
        blksread = savecnt;
        /*
         * If continuing from the previous volume, skip over any
         * blocks read already at the end of the previous volume.
         *
         * If coming to this volume at random, skip to the beginning
         * of the next record.
         */
        Dprintf(stdout, "read %ld recs, tape starts with %ld\n",
                tpblksread, (long)tmpbuf.c_firstrec);
        if (tmpbuf.c_type == TS_TAPE && (tmpbuf.c_flags & DR_NEWHEADER)) {
                if (!wantnext) {
                        tpblksread = tmpbuf.c_firstrec;
                        for (i = tmpbuf.c_count; i > 0; i--)
                                readtape(buf);
                } else if (tmpbuf.c_firstrec > 0 &&
                           tmpbuf.c_firstrec < tpblksread - 1) {
                        /*
                         * -1 since we've read the volume header
                         */
                        i = tpblksread - tmpbuf.c_firstrec - 1;
                        Dprintf(stderr, "Skipping %ld duplicate record%s.\n",
                                (long)i, i > 1 ? "s" : "");
                        while (--i >= 0)
                                readtape(buf);
                }
        }
        if (curfile.action == USING) {
                if (volno == 1)
                        panic("active file into volume 1\n");
                return;
        }
        /*
         * Skip up to the beginning of the next record
         */
        if (tmpbuf.c_type == TS_TAPE && (tmpbuf.c_flags & DR_NEWHEADER))
                for (i = tmpbuf.c_count; i > 0; i--)
                        readtape(buf);
        (void) gethead(&spcl);
        findinode(&spcl);
        if (gettingfile) {
                gettingfile = 0;
                siglongjmp(restart, 1);
        }
}

/*
 * Handle unexpected EOF.
 */
static void
terminateinput(void)
{

        if (gettingfile && curfile.action == USING) {
                printf("Warning: %s %s\n",
                    "End-of-input encountered while extracting", curfile.name);
        }
        curfile.name = "<name unknown>";
        curfile.action = UNKNOWN;
        curfile.dip = NULL;
        curfile.ino = maxino;
        if (gettingfile) {
                gettingfile = 0;
                siglongjmp(restart, 1);
        }
}

/*
 * handle multiple dumps per tape by skipping forward to the
 * appropriate one.
 */
static void
setdumpnum(void)
{
        struct mtop tcom;

        if (dumpnum == 1 || volno != 1)
                return;
        if (pipein)
                errx(1, "Cannot have multiple dumps on pipe input");
        tcom.mt_op = MTFSF;
        tcom.mt_count = dumpnum - 1;
#ifdef RRESTORE
        if (host)
                rmtioctl(MTFSF, dumpnum - 1);
        else
#endif
                if (ioctl(mt, (int)MTIOCTOP, (char *)&tcom) < 0)
                        warn("ioctl MTFSF");
}

void
printdumpinfo(void)
{
        fprintf(stdout, "Dump   date: %s", ctime4(&spcl.c_date));
        fprintf(stdout, "Dumped from: %s",
            (spcl.c_ddate == 0) ? "the epoch\n" : ctime4(&spcl.c_ddate));
        if (spcl.c_host[0] == '\0')
                return;
        fprintf(stdout, "Level %d dump of %s on %s:%s\n",
                spcl.c_level, spcl.c_filesys, spcl.c_host, spcl.c_dev);
        fprintf(stdout, "Label: %s\n", spcl.c_label);
}

int
extractfile(char *name)
{
        unsigned int flags;
        mode_t mode;
        struct timeval timep[2];
        struct entry *ep;

        curfile.name = name;
        curfile.action = USING;
#ifdef  __linux__
        timep[0].tv_sec = curfile.dip->di_atime.tv_sec;
        timep[0].tv_usec = curfile.dip->di_atime.tv_usec;
        timep[1].tv_sec = curfile.dip->di_mtime.tv_sec;
        timep[1].tv_usec = curfile.dip->di_mtime.tv_usec;
#else   /* __linux__ */
        timep[0].tv_sec = curfile.dip->di_atime;
        timep[0].tv_usec = curfile.dip->di_atimensec / 1000;
        timep[1].tv_sec = curfile.dip->di_mtime;
        timep[1].tv_usec = curfile.dip->di_mtimensec / 1000;
#endif  /* __linux__ */
        mode = curfile.dip->di_mode;
        flags = curfile.dip->di_flags;
        switch (mode & IFMT) {

        default:
                fprintf(stderr, "%s: unknown file mode 0%o\n", name, mode);
                skipfile();
                return (FAIL);

        case IFSOCK:
                Vprintf(stdout, "skipped socket %s\n", name);
                skipfile();
                return (GOOD);

        case IFDIR:
                if (mflag) {
                        ep = lookupname(name);
                        if (ep == NULL || ep->e_flags & EXTRACT)
                                panic("unextracted directory %s\n", name);
                        skipfile();
                        return (GOOD);
                }
                Vprintf(stdout, "extract file %s\n", name);
                return (genliteraldir(name, curfile.ino));

        case IFLNK:
        {
#ifdef HAVE_LCHOWN
                uid_t luid = curfile.dip->di_uid;
                gid_t lgid = curfile.dip->di_gid;
#endif
                lnkbuf[0] = '\0';
                pathlen = 0;
                getfile(xtrlnkfile, xtrlnkskip);
                if (pathlen == 0) {
                        Vprintf(stdout,
                            "%s: zero length symbolic link (ignored)\n", name);
                        return (GOOD);
                }
                if (linkit(lnkbuf, name, SYMLINK) == FAIL)
                        return (FAIL);
#ifdef HAVE_LCHOWN
                (void) lchown(name, luid, lgid);
#endif
                return (GOOD);
        }

        case IFIFO:
                Vprintf(stdout, "extract fifo %s\n", name);
                if (Nflag) {
                        skipfile();
                        return (GOOD);
                }
                if (uflag && !Nflag)
                        (void)unlink(name);
                if (mkfifo(name, mode) < 0) {
                        warn("%s: cannot create fifo", name);
                        skipfile();
                        return (FAIL);
                }
                (void) chown(name, curfile.dip->di_uid, curfile.dip->di_gid);
                (void) chmod(name, mode);
                if (flags)
#ifdef  __linux__
                        (void) fsetflags(name, flags);
#else
                        (void) chflags(name, flags);
#endif
                skipfile();
                utimes(name, timep);
                return (GOOD);

        case IFCHR:
        case IFBLK:
                Vprintf(stdout, "extract special file %s\n", name);
                if (Nflag) {
                        skipfile();
                        return (GOOD);
                }
                if (uflag)
                        (void)unlink(name);
                if (mknod(name, mode, (int)curfile.dip->di_rdev) < 0) {
                        warn("%s: cannot create special file", name);
                        skipfile();
                        return (FAIL);
                }
                (void) chown(name, curfile.dip->di_uid, curfile.dip->di_gid);
                (void) chmod(name, mode);
                if (flags)
#ifdef  __linux__
                        {
                        warn("%s: fsetflags called on a special file", name);
                        (void) fsetflags(name, flags);
                        }
#else
                        (void) chflags(name, flags);
#endif
                skipfile();
                utimes(name, timep);
                return (GOOD);

        case IFREG:
                Vprintf(stdout, "extract file %s\n", name);
                if (Nflag) {
                        skipfile();
                        return (GOOD);
                }
                if (uflag)
                        (void)unlink(name);
                if ((ofile = open(name, O_WRONLY | O_CREAT | O_TRUNC,
                    0666)) < 0) {
                        warn("%s: cannot create file", name);
                        skipfile();
                        return (FAIL);
                }
                (void) fchown(ofile, curfile.dip->di_uid, curfile.dip->di_gid);
                (void) fchmod(ofile, mode);
                if (flags)
#ifdef  __linux__
                        (void) setflags(ofile, flags);
#else
                        (void) fchflags(ofile, flags);
#endif
                getfile(xtrfile, xtrskip);
                (void) close(ofile);
                utimes(name, timep);
                return (GOOD);
        }
        /* NOTREACHED */
}

/*
 * skip over bit maps on the tape
 */
void
skipmaps(void)
{

        while (spcl.c_type == TS_BITS || spcl.c_type == TS_CLRI)
                skipfile();
}

/*
 * skip over a file on the tape
 */
void
skipfile(void)
{

        curfile.action = SKIP;
        getfile(xtrnull, xtrnull);
}

/*
 * Extract a file from the tape.
 * When an allocated block is found it is passed to the fill function;
 * when an unallocated block (hole) is found, a zeroed buffer is passed
 * to the skip function.
 */
void
getfile(void (*fill) __P((char *, size_t)), void (*skip) __P((char *, size_t)))
{
        register int i;
        volatile int curblk = 0;
        volatile quad_t size = spcl.c_dinode.di_size;
        volatile int last_write_was_hole = 0;
        quad_t origsize = size;
        static char clearedbuf[MAXBSIZE];
        char buf[MAXBSIZE / TP_BSIZE][TP_BSIZE];
        char junk[TP_BSIZE];

        if (spcl.c_type == TS_END)
                panic("ran off end of tape\n");
        if (spcl.c_magic != NFS_MAGIC)
                panic("not at beginning of a file\n");
        if (!gettingfile && setjmp(restart) != 0)
                return;
        gettingfile++;
loop:
        for (i = 0; i < spcl.c_count; i++) {
                if (readmapflag || spcl.c_addr[i]) {
                        readtape(&buf[curblk++][0]);
                        if (curblk == fssize / TP_BSIZE) {
                                (*fill)((char *)buf, (size_t)(size > TP_BSIZE ?
                                     fssize : (curblk - 1) * TP_BSIZE + size));
                                curblk = 0;
                                last_write_was_hole = 0;
                        }
                } else {
                        if (curblk > 0) {
                                (*fill)((char *)buf, (size_t)(size > TP_BSIZE ?
                                     curblk * TP_BSIZE :
                                     (curblk - 1) * TP_BSIZE + size));
                                curblk = 0;
                        }
                        (*skip)(clearedbuf, (long)(size > TP_BSIZE ?
                                TP_BSIZE : size));
                        last_write_was_hole = 1;
                }
                if ((size -= TP_BSIZE) <= 0) {
                        for (i++; i < spcl.c_count; i++)
                                if (readmapflag || spcl.c_addr[i])
                                        readtape(junk);
                        break;
                }
        }
        if (gethead(&spcl) == GOOD && size > 0) {
                if (spcl.c_type == TS_ADDR)
                        goto loop;
                Dprintf(stdout,
                        "Missing address (header) block for %s at %ld blocks\n",
                        curfile.name, (long)blksread);
        }
        if (curblk > 0) {
                (*fill)((char *)buf, (size_t)(curblk * TP_BSIZE) + size);
                last_write_was_hole = 0;
        }
        if (last_write_was_hole) {
                ftruncate(ofile, origsize);
        }
        findinode(&spcl);
        gettingfile = 0;
}

/*
 * Write out the next block of a file.
 */
static void
xtrfile(char *buf, size_t size)
{

        if (Nflag)
                return;
        if (write(ofile, buf, (int) size) == -1)
                err(1, "write error extracting inode %lu, name %s\nwrite",
                        (unsigned long)curfile.ino, curfile.name);
}

/*
 * Skip over a hole in a file.
 */
/* ARGSUSED */
static void
xtrskip(char *buf, size_t size)
{

        if (lseek(ofile, (off_t)size, SEEK_CUR) == -1)
                err(1, "seek error extracting inode %lu, name %s\nlseek",
                        (unsigned long)curfile.ino, curfile.name);
}

/*
 * Collect the next block of a symbolic link.
 */
static void
xtrlnkfile(char *buf, size_t size)
{

        pathlen += size;
        if (pathlen > MAXPATHLEN)
                errx(1, "symbolic link name: %s->%s%s; too long %d",
                    curfile.name, lnkbuf, buf, pathlen);
        (void) strcat(lnkbuf, buf);
}

/*
 * Skip over a hole in a symbolic link (should never happen).
 */
/* ARGSUSED */
static void
xtrlnkskip(char *buf, size_t size)
{

        errx(1, "unallocated block in symbolic link %s", curfile.name);
}

/*
 * Collect the next block of a bit map.
 */
static void
xtrmap(char *buf, size_t size)
{

        memmove(map, buf, size);
        map += size;
}

/*
 * Skip over a hole in a bit map (should never happen).
 */
/* ARGSUSED */
static void
xtrmapskip(char *buf, size_t size)
{

        panic("hole in map\n");
        map += size;
}

/*
 * Noop, when an extraction function is not needed.
 */
/* ARGSUSED */
void
xtrnull(char *buf, size_t size)
{

        return;
}

#if COMPARE_ONTHEFLY
/*
 * Compare the next block of a file.
 */
static void
xtrcmpfile(char *buf, size_t size)
{
        static char cmpbuf[MAXBSIZE];

        if (cmperror)
                return;
        
        if (read(ifile, cmpbuf, size) != size) {
                fprintf(stderr, "%s: size has changed.\n", 
                        curfile.name);
                cmperror = 1;
                return;
        }
        
        if (memcmp(buf, cmpbuf, size) != 0) {
                fprintf(stderr, "%s: tape and disk copies are different\n",
                        curfile.name);
                cmperror = 1;
                return;
        }
}

/*
 * Skip over a hole in a file.
 */
static void
xtrcmpskip(char *buf, size_t size)
{
        static char cmpbuf[MAXBSIZE];
        int i;

        if (cmperror)
                return;
        
        if (read(ifile, cmpbuf, size) != size) {
                fprintf(stderr, "%s: size has changed.\n", 
                        curfile.name);
                cmperror = 1;
                return;
        }

        for (i = 0; i < size; ++i)
                if (cmpbuf[i] != '\0') {
                        fprintf(stderr, "%s: tape and disk copies are different\n",
                                curfile.name);
                        cmperror = 1;
                        return;
                }
}
#endif /* COMPARE_ONTHEFLY */

#if !COMPARE_ONTHEFLY
static int
do_cmpfiles(int fd_tape, int fd_disk, long size)
{
        static char buf_tape[BUFSIZ];
        static char buf_disk[BUFSIZ];
        ssize_t n_tape;
        ssize_t n_disk;

        while (size > 0) {
                if ((n_tape = read(fd_tape, buf_tape, sizeof(buf_tape))) < 1) {
                        close(fd_tape), close(fd_disk);
                        panic("do_cmpfiles: unexpected EOF[1]");
                }
                if ((n_disk = read(fd_disk, buf_disk, sizeof(buf_tape))) < 1) {
                        close(fd_tape), close(fd_disk);
                        panic("do_cmpfiles: unexpected EOF[2]");
                }
                if (n_tape != n_disk) {
                        close(fd_tape), close(fd_disk);
                        panic("do_cmpfiles: sizes different!");
                }
                if (memcmp(buf_tape, buf_disk, (size_t)n_tape) != 0) return (1);
                size -= n_tape;
        }
        return (0);
}

/* for debugging compare problems */
#undef COMPARE_FAIL_KEEP_FILE

static
#ifdef COMPARE_FAIL_KEEP_FILE
/* return true if tapefile should be unlinked after compare */
int
#else
void
#endif
cmpfiles(char *tapefile, char *diskfile, struct stat *sbuf_disk)
{
        struct stat sbuf_tape;
        int fd_tape, fd_disk;

        if (stat(tapefile, &sbuf_tape) != 0) {
                panic("Can't lstat tmp file %s: %s\n", tapefile,
                      strerror(errno));
                compare_errors = 1;
        }

        if (sbuf_disk->st_size != sbuf_tape.st_size) {
                fprintf(stderr,
                        "%s: size changed from %ld to %ld.\n",
                        diskfile, (long)sbuf_tape.st_size, (long)sbuf_disk->st_size);
                compare_errors = 1;
#ifdef COMPARE_FAIL_KEEP_FILE
                return (0);
#else
                return;
#endif
        }

        if ((fd_tape = open(tapefile, O_RDONLY)) < 0) {
                panic("Can't open %s: %s\n", tapefile, strerror(errno));
                compare_errors = 1;
        }
        if ((fd_disk = open(diskfile, O_RDONLY)) < 0) {
                close(fd_tape);
                panic("Can't open %s: %s\n", diskfile, strerror(errno));
                compare_errors = 1;
        }

        if (do_cmpfiles(fd_tape, fd_disk, sbuf_tape.st_size)) {
                fprintf(stderr, "%s: tape and disk copies are different\n",
                        diskfile);
                close(fd_tape);
                close(fd_disk);
                compare_errors = 1;
#ifdef COMPARE_FAIL_KEEP_FILE
                /* rename the file to live in /tmp */
                /* rename `tapefile' to /tmp/<basename of diskfile> */
                {
                        char *p = strrchr(diskfile, '/');
                        char newname[MAXPATHLEN];
                        if (!p) {
                                panic("can't find / in %s\n", diskfile);
                        }
                        snprintf(newname, sizeof(newname), "%s/debug/%s", tmpdir, p + 1);
                        if (rename(tapefile, newname)) {
                                panic("rename from %s to %s failed: %s\n",
                                      tapefile, newname,
                                      strerror(errno));
                        } else {
                                fprintf(stderr, "*** %s saved to %s\n",
                                        tapefile, newname);
                        }
                }
                
                /* don't unlink the file (it's not there anymore */
                /* anyway) */
                return (0);
#else
                return;
#endif
        }
        close(fd_tape);
        close(fd_disk);
#ifdef COMPARE_FAIL_KEEP_FILE
        return (1);
#endif
}
#endif /* !COMPARE_ONTHEFLY */

#if !COMPARE_ONTHEFLY
static char tmpfilename[MAXPATHLEN];
#endif

void
comparefile(char *name)
{
        int mode;
        struct stat sb;
        int r;
#if !COMPARE_ONTHEFLY
        static char *tmpfile = NULL;
        struct stat stemp;
#endif

        if ((r = lstat(name, &sb)) != 0) {
                warn("%s: does not exist (%d)", name, r);
                compare_errors = 1;
                skipfile();
                return;
        }

        curfile.name = name;
        curfile.action = USING;
        mode = curfile.dip->di_mode;

        Vprintf(stdout, "comparing %s (size: %ld, mode: 0%o)\n", name,
                (long)sb.st_size, mode);

        if (sb.st_mode != mode) {
                fprintf(stderr, "%s: mode changed from 0%o to 0%o.\n",
                        name, mode & 07777, sb.st_mode & 07777);
                compare_errors = 1;
        }
        switch (mode & IFMT) {
        default:
                skipfile();
                return;

        case IFSOCK:
                skipfile();
                return;

        case IFDIR:
                skipfile();
                return;

        case IFLNK: {
                char lbuf[MAXPATHLEN + 1];
                int lsize;

                if (!(sb.st_mode & S_IFLNK)) {
                        fprintf(stderr, "%s: is no longer a symbolic link\n",
                                name);
                        compare_errors = 1;
                        return;
                }
                lnkbuf[0] = '\0';
                pathlen = 0;
                getfile(xtrlnkfile, xtrlnkskip);
                if (pathlen == 0) {
                        fprintf(stderr,
                                "%s: zero length symbolic link (ignored)\n",
                                name);
                        compare_errors = 1;
                        return;
                }
                if ((lsize = readlink(name, lbuf, MAXPATHLEN)) < 0) {
                        panic("readlink of %s failed: %s", name,
                              strerror(errno));
                        compare_errors = 1;
                }
                lbuf[lsize] = 0;
                if (strcmp(lbuf, lnkbuf) != 0) {
                        fprintf(stderr,
                                "%s: symbolic link changed from %s to %s.\n",
                                name, lnkbuf, lbuf);
                        compare_errors = 1;
                        return;
                }
                return;
        }

        case IFCHR:
        case IFBLK:
                if (!(sb.st_mode & (S_IFCHR|S_IFBLK))) {
                        fprintf(stderr, "%s: no longer a special file\n",
                                name);
                        compare_errors = 1;
                        skipfile();
                        return;
                }

                if (sb.st_rdev != (int)curfile.dip->di_rdev) {
                        fprintf(stderr,
                                "%s: device changed from %d,%d to %d,%d.\n",
                                name,
                                ((int)curfile.dip->di_rdev >> 8) & 0xff,
                                (int)curfile.dip->di_rdev & 0xff,
                                ((int)sb.st_rdev >> 8) & 0xff,
                                (int)sb.st_rdev & 0xff);
                        compare_errors = 1;
                }
                skipfile();
                return;

        case IFREG:
#if COMPARE_ONTHEFLY
                if ((ifile = open(name, O_RDONLY)) < 0) {
                        panic("Can't open %s: %s\n", name, strerror(errno));
                        skipfile();
                        compare_errors = 1;
                }
                else {
                        cmperror = 0;
                        getfile(xtrcmpfile, xtrcmpskip);
                        if (!cmperror) {
                                char c;
                                if (read(ifile, &c, 1) != 0) {
                                        fprintf(stderr, "%s: size has changed.\n", 
                                                name);
                                        cmperror = 1;
                                }
                        }
                        if (cmperror)
                                compare_errors = 1;
                        close(ifile);
                }
#else
                if (tmpfile == NULL) {
                        /* argument to mktemp() must not be in RO space: */
                        snprintf(tmpfilename, sizeof(tmpfilename), "%s/restoreCXXXXXX", tmpdir);
                        tmpfile = mktemp(&tmpfilename[0]);
                }
                if ((stat(tmpfile, &stemp) == 0) && (unlink(tmpfile) != 0)) {
                        panic("cannot delete tmp file %s: %s\n",
                              tmpfile, strerror(errno));
                }
                if ((ofile = creat(tmpfile, 0600)) < 0) {
                        panic("cannot create file temp file %s: %s\n",
                              name, strerror(errno));
                }
                getfile(xtrfile, xtrskip);
                (void) close(ofile);
#ifdef COMPARE_FAIL_KEEP_FILE
                if (cmpfiles(tmpfile, name, &sb))
                        unlink(tmpfile);
#else
                cmpfiles(tmpfile, name, &sb);
                unlink(tmpfile);
#endif
#endif /* COMPARE_ONTHEFLY */
                return;
        }
        /* NOTREACHED */
}

#ifdef HAVE_ZLIB
static void (*readtape_func)(char *) = readtape_set;

/*
 * Read TP_BSIZE blocks from the input.
 * Handle read errors, and end of media.
 * Decompress compressed blocks.
 */
static void
readtape(char *buf)
{
        (*readtape_func)(buf);  /* call the actual processing routine */
}

/*
 * Set function pointer for readtape() routine. zflag and magtapein must
 * be correctly set before the first call to readtape().
 */
static void
readtape_set(char *buf)
{
        if (!zflag) 
                readtape_func = readtape_uncompr;
        else {
                if (magtapein)
                        readtape_func = readtape_comprtape;
                else
                        readtape_func = readtape_comprfile;
        }
        readtape(buf);
}

#endif /* HAVE_ZLIB */

/*
 * This is the original readtape(), it's used for reading uncompressed input.
 * Read TP_BSIZE blocks from the input.
 * Handle read errors, and end of media.
 */
static void
#ifdef HAVE_ZLIB
readtape_uncompr(char *buf)
#else
readtape(char *buf)
#endif
{
        ssize_t rd, newvol, i;
        int cnt, seek_failed;

        if (blkcnt < numtrec) {
                memmove(buf, &tbufptr[(blkcnt++ * TP_BSIZE)], TP_BSIZE);
                blksread++;
                tpblksread++;
                return;
        }
        tbufptr = tapebuf;
        for (i = 0; i < ntrec; i++)
                ((struct s_spcl *)&tapebuf[i * TP_BSIZE])->c_magic = 0;
        if (numtrec == 0)
                numtrec = ntrec;
        cnt = ntrec * TP_BSIZE;
        if (zflag)
                cnt += PREFIXSIZE;
        rd = 0;
getmore:
#ifdef RRESTORE
        if (host)
                i = rmtread(&tapebuf[rd], cnt);
        else
#endif
                i = read(mt, &tapebuf[rd], cnt);

        /*
         * Check for mid-tape short read error.
         * If found, skip rest of buffer and start with the next.
         */
        if (!pipein && numtrec < ntrec && i > 0) {
                Dprintf(stdout, "mid-media short read error.\n");
                numtrec = ntrec;
        }
        /*
         * Handle partial block read.
         */
        if (pipein && i == 0 && rd > 0)
                i = rd;
        else if (i > 0 && i != ntrec * TP_BSIZE) {
                if (pipein) {
                        rd += i;
                        cnt -= i;
                        if (cnt > 0)
                                goto getmore;
                        i = rd;
                } else {
                        /*
                         * Short read. Process the blocks read.
                         */
                        if (i % TP_BSIZE != 0)
                                Vprintf(stdout,
                                    "partial block read: %ld should be %ld\n",
                                    (long)i, ntrec * TP_BSIZE);
                        numtrec = i / TP_BSIZE;
                }
        }
        /*
         * Handle read error.
         */
        if (i < 0) {
                fprintf(stderr, "Tape read error while ");
                switch (curfile.action) {
                default:
                        fprintf(stderr, "trying to set up tape\n");
                        break;
                case UNKNOWN:
                        fprintf(stderr, "trying to resynchronize\n");
                        break;
                case USING:
                        fprintf(stderr, "restoring %s\n", curfile.name);
                        break;
                case SKIP:
                        fprintf(stderr, "skipping over inode %lu\n",
                                (unsigned long)curfile.ino);
                        break;
                }
                if (!yflag && !reply("continue"))
                        exit(1);
                i = ntrec * TP_BSIZE;
                memset(tapebuf, 0, (size_t)i);
#ifdef RRESTORE
                if (host)
                        seek_failed = (rmtseek(i, 1) < 0);
                else
#endif
                        seek_failed = (lseek(mt, i, SEEK_CUR) == (off_t)-1);

                if (seek_failed) {
                        warn("continuation failed");
                        if (!yflag && !reply("assume end-of-tape and continue"))
                                exit(1);
                        i = 0;
                }
        }
        /*
         * Handle end of tape.
         */
        if (i == 0) {
                Vprintf(stdout, "End-of-tape encountered\n");
                if (!pipein) {
                        newvol = volno + 1;
                        volno = 0;
                        numtrec = 0;
                        getvol(newvol);
                        readtape(buf);
                        return;
                }
                if (rd % TP_BSIZE != 0)
                        panic("partial block read: %d should be %d\n",
                                rd, ntrec * TP_BSIZE);
                terminateinput();
                memmove(&tapebuf[rd], &endoftapemark, TP_BSIZE);
        }
        blkcnt = 0;
        memmove(buf, &tbufptr[(blkcnt++ * TP_BSIZE)], TP_BSIZE);
        blksread++;
        tpblksread++;
}

#ifdef HAVE_ZLIB

/*
 * Read a compressed format block from a file or pipe and uncompress it.
 * Attempt to handle read errors, and end of file. 
 */
static void
readtape_comprfile(char *buf)
{
        long rl, size, i, ret;
        int newvol; 
        struct tapebuf *tpb;

        if (blkcnt < numtrec) {
                memmove(buf, &tbufptr[(blkcnt++ * TP_BSIZE)], TP_BSIZE);
                blksread++;
                tpblksread++;
                return;
        }
        /* need to read the next block */
        tbufptr = tapebuf;
        for (i = 0; i < ntrec; i++)
                ((struct s_spcl *)&tapebuf[i * TP_BSIZE])->c_magic = 0;
        numtrec = ntrec;
        tpb = (struct tapebuf *) tapebuf;

        /* read the block prefix */
        ret = read_a_block(mt, tapebuf, PREFIXSIZE, &rl);
        if (ret <= 0)
                goto readerr;

        /* read the data */
        size = tpb->length;
        if (size > bufsize)  {
                /* something's wrong */
                Vprintf(stdout, "Prefix size error, max size %d, got %ld\n",
                        bufsize, size);
                size = bufsize;
                tpb->length = bufsize;
        }
        ret = read_a_block(mt, tpb->buf, size, &rl);
        if (ret <= 0)
                goto readerr;

        tbufptr = decompress_tapebuf(tpb, rl + PREFIXSIZE);
        if (tbufptr == NULL) {
                msg_read_error("File decompression error while");
                if (!yflag && !reply("continue"))
                        exit(1);
                memset(tapebuf, 0, bufsize);
                tbufptr = tapebuf;
        }

        blkcnt = 0;
        memmove(buf, &tbufptr[(blkcnt++ * TP_BSIZE)], TP_BSIZE);
        blksread++;
        tpblksread++;
        return;

readerr:
        /* Errors while reading from a file or pipe are catastrophic. Since
         * there are no block boundaries, it's impossible to bypass the
         * block in error and find the start of the next block.
         */
        if (ret == 0) {
                /* It's possible to have multiple input files using -M
                 * and -f file1,file2...
                 */
                Vprintf(stdout, "End-of-File encountered\n");
                if (!pipein) {
                        newvol = volno + 1;
                        volno = 0;
                        numtrec = 0;
                        getvol(newvol);
                        readtape(buf);
                        return;
                }
        }
        msg_read_error("Read error while");
        /* if (!yflag && !reply("continue")) */
                exit(1);
}

/*
 * Read compressed data from a tape and uncompress it.
 * Handle read errors, and end of media.
 * Since a tape consists of separate physical blocks, we try
 * to recover from errors by repositioning the tape to the next
 * block.
 */
static void
readtape_comprtape(char *buf)
{
        long rl, size, i;
        int ret, newvol;
        struct tapebuf *tpb;
        struct mtop tcom;

        if (blkcnt < numtrec) {
                memmove(buf, &tbufptr[(blkcnt++ * TP_BSIZE)], TP_BSIZE);
                blksread++;
                tpblksread++;
                return;
        }
        /* need to read the next block */
        tbufptr = tapebuf;
        for (i = 0; i < ntrec; i++)
                ((struct s_spcl *)&tapebuf[i * TP_BSIZE])->c_magic = 0;
        numtrec = ntrec;
        tpb = (struct tapebuf *) tapebuf;

        /* read the block */
        size = bufsize + PREFIXSIZE;
        ret = read_a_block(mt, tapebuf, size, &rl);
        if (ret <= 0)
                goto readerr;

        tbufptr = decompress_tapebuf(tpb, rl);
        if (tbufptr == NULL) {
                msg_read_error("Tape decompression error while");
                if (!yflag && !reply("continue"))
                        exit(1);
                memset(tapebuf, 0, PREFIXSIZE + bufsize);
                tbufptr = tapebuf;
        }
        goto moverecord;

readerr:
        /* Handle errors: EOT switches to the next volume, other errors
         * attempt to position the tape to the next block.
         */
        if (ret == 0) {
                Vprintf(stdout, "End-of-tape encountered\n");
                newvol = volno + 1;
                volno = 0;
                numtrec = 0;
                getvol(newvol);
                readtape(buf);
                return;
        }

        msg_read_error("Tape read error while");
        if (!yflag && !reply("continue"))
                exit(1);
        memset(tapebuf, 0, PREFIXSIZE + bufsize);
        tbufptr = tapebuf;

#ifdef RRESTORE
        if (host)
                rl = rmtioctl(MTFSR, 1);
        else
#endif
        {
                tcom.mt_op = MTFSR;
                tcom.mt_count = 1;
                rl = ioctl(mt, MTIOCTOP, &tcom);
        }

        if (rl < 0) {
                warn("continuation failed");
                if (!yflag && !reply("assume end-of-tape and continue"))
                        exit(1);
                ret = 0;         /* end of tape */
                goto readerr;
        }

moverecord:
        blkcnt = 0;
        memmove(buf, &tbufptr[(blkcnt++ * TP_BSIZE)], TP_BSIZE);
        blksread++;
        tpblksread++;
}

/*
 *  Decompress a struct tapebuf into a buffer. readsize is the size read
 *  from the tape/file and is used for error messages. Returns a pointer
 *  to the location of the uncompressed buffer or NULL on errors.
 *  Adjust numtrec and complain for a short block.
 */
static char *
decompress_tapebuf(struct tapebuf *tpbin, int readsize)
{
        /* If zflag is on, all blocks have a struct tapebuf prefix */
        /* zflag gets set in setup() from the dump header          */
        int cresult, blocklen;        
        unsigned long worklen;
        char *output = NULL,*reason = NULL, *lengtherr = NULL;              
       
        /* build a length error message */
        blocklen = tpbin->length;
        if (readsize < blocklen + PREFIXSIZE)
                lengtherr = "short";
        else
                if (readsize > blocklen + PREFIXSIZE)
                        lengtherr = "long";

        worklen = comprlen;
        cresult = Z_OK;
        if (tpbin->compressed) {
                /* uncompress whatever we read, if it fails, complain later */
                cresult = uncompress(comprbuf, &worklen, tpbin->buf, blocklen);
                output = comprbuf;
        }
        else {
                output = tpbin->buf;
                worklen = blocklen;
        }
        switch (cresult) {
                case Z_OK:
                        if (worklen != ntrec * TP_BSIZE) {
                                /* short block, shouldn't happen, but... */
                                reason = "length mismatch";
                                if (worklen % TP_BSIZE == 0)
                                        numtrec = worklen / TP_BSIZE;
                        }
                        break;
                case Z_MEM_ERROR:
                        reason = "not enough memory";
                        break;
                case Z_BUF_ERROR:
                        reason = "buffer too small";
                        break;
                case Z_DATA_ERROR:
                        reason = "data error";
                        break;
                default:
                        reason = "unknown";
        } /*switch */
        if (reason) {
                if (lengtherr)
                        fprintf(stderr, "%s compressed block: %d expected: %d\n",
                                lengtherr, readsize, tpbin->length + PREFIXSIZE);
                fprintf(stderr, "decompression error, block %ld: %s\n",
                        tpblksread+1, reason);
                if (cresult != Z_OK)   output = NULL;
        }
        return output;
}

/*
 * Print an error message for a read error.
 * This was exteracted from the original readtape().
 */
static void
msg_read_error(char *m)
{
        switch (curfile.action) {
                default:
                        fprintf(stderr, "%s trying to set up tape\n", m);
                        break;
                case UNKNOWN:
                        fprintf(stderr, "%s trying to resynchronize\n", m);
                        break;
                case USING:
                        fprintf(stderr, "%s restoring %s\n", m, curfile.name);
                        break;
                case SKIP:
                        fprintf(stderr, "%s skipping over inode %lu\n", m,
                                (unsigned long)curfile.ino);
                        break;
        }
}
#endif /* HAVE_ZLIB */

/*
 * Read the first block and set the blocksize from its length. Test
 * if the block looks like a compressed dump tape. setup() will make
 * the final determination by checking the compressed flag if gethead()
 * finds a valid header. The test here is necessary to offset the buffer
 * by the size of the compressed prefix. zflag is set here so that
 * readtape_set can set the correct function pointer for readtape().
 * Note that the first block of each tape/file will not be compressed.
 */ 
static void
findtapeblksize(void)
{
        long i;
        size_t len;
        struct tapebuf *tpb = (struct tapebuf *) tapebuf;
        struct s_spcl *spclpt = (struct s_spcl *) tpb->buf;

        for (i = 0; i < ntrec; i++)
                ((struct s_spcl *)&tapebuf[i * TP_BSIZE])->c_magic = 0;
        blkcnt = 0;
        tbufptr = tapebuf;
        /*
         * For a pipe or file, read in the first record. For a tape, read
         * the first block.
         */
        len = magtapein ? bufsize + PREFIXSIZE: TP_BSIZE;

        if (read_a_block(mt, tapebuf, len, &i) <= 0)
                errx(1, "Tape read error on first record");

        /*
         * If the input is from a file or a pipe, we read TP_BSIZE
         * bytes looking for a compressed dump header, we then
         * need to read in the rest of the record, as determined by
         * tpb->length or bufsize. The first block of the dump is
         * guaranteed to not be compressed so we look at the header.
         */
        if (!magtapein) {
                if (tpb->length % TP_BSIZE == 0
                    && tpb->length <= bufsize
                    && tpb->compressed == 0
                    && spclpt->c_type == TS_TAPE 
                    && spclpt->c_flags & DR_COMPRESSED) {
                        /* Looks like it's a compressed dump block prefix, */
                        /* read in the rest of the block based on tpb->length. */
                        len = tpb->length - TP_BSIZE + PREFIXSIZE;
                        if (read_a_block(mt, tapebuf+TP_BSIZE, len, &i) <= 0
                            || i != len)
                                errx(1,"Error reading dump file header");
                        tbufptr = tpb->buf;
                        numtrec = ntrec = tpb->length / TP_BSIZE;
                        zflag = 1;   
                }
                else {
                        /* read in the rest of the block based on bufsize */
                        len = bufsize - TP_BSIZE;
                        if (read_a_block(mt, tapebuf+TP_BSIZE, len, &i) <= 0
                            || i != len)
                                errx(1,"Error reading dump file header");
                        tbufptr = tapebuf;
                        numtrec = ntrec;
                }
                Vprintf(stdout, "Input block size is %ld\n", ntrec);
                return;
        }

        /*
         * If the input is a tape, we tried to read PREFIXSIZE +
         * ntrec * TP_BSIZE bytes. If it's not a compressed dump tape
         * or the value of ntrec is too large, we have read less than
         * what we asked for; adjust the value of ntrec and test for
         * a compressed dump tape prefix.
         */

        if (i % TP_BSIZE != 0) {
                if (i % TP_BSIZE == PREFIXSIZE
                    && tpb->compressed == 0
                    && spclpt->c_type == TS_TAPE
                    && spclpt->c_flags & DR_COMPRESSED) {

                        zflag = 1;
                        tbufptr = tpb->buf;
                        if (tpb->length > bufsize)
                                errx(1, "Tape blocksize is too large, use "
                                        "\'-b %d\' ", tpb->length / TP_BSIZE);
                }
                else
                        errx(1, "Tape block size (%ld) is not a multiple of dump block size (%d)",
                                i, TP_BSIZE);
        }
        ntrec = i / TP_BSIZE;
        numtrec = ntrec;
        Vprintf(stdout, "Tape block size is %ld\n", ntrec);
}

/*
 * Read a block of data handling all of the messy details.
 */
static int read_a_block(int fd, void *buf, size_t len, long *lengthread)
{
        long i = 1, size;

        size = len;
        while (size > 0) {
#ifdef RRESTORE
                if (host)
                        i = rmtread(buf, size);
                else
#endif
                        i = read(fd, buf, size);                 

                if (i <= 0)
                        break; /* EOD or error */
                size -= i;
                if (magtapein)
                        break; /* block at a time for mt */
                buf += i;
        }
        *lengthread = len - size;
        return i;
}

void
closemt(void)
{

        if (mt < 0)
                return;
#ifdef RRESTORE
        if (host)
                rmtclose();
        else
#endif
                (void) close(mt);
}

/*
 * Read the next block from the tape.
 * Check to see if it is one of several vintage headers.
 * If it is an old style header, convert it to a new style header.
 * If it is not any valid header, return an error.
 */
static int
gethead(struct s_spcl *buf)
{
        int32_t i;
        union {
                quad_t  qval;
                int32_t val[2];
        } qcvt;
        union u_ospcl {
                char dummy[TP_BSIZE];
                struct  s_ospcl {
                        int32_t c_type;
                        int32_t c_date;
                        int32_t c_ddate;
                        int32_t c_volume;
                        int32_t c_tapea;
                        u_int16_t c_inumber;
                        int32_t c_magic;
                        int32_t c_checksum;
                        struct odinode {
                                u_int16_t odi_mode;
                                u_int16_t odi_nlink;
                                u_int16_t odi_uid;
                                u_int16_t odi_gid;
                                int32_t odi_size;
                                int32_t odi_rdev;
                                char    odi_addr[36];
                                int32_t odi_atime;
                                int32_t odi_mtime;
                                int32_t odi_ctime;
                        } c_dinode;
                        int32_t c_count;
                        char    c_addr[256];
                } s_ospcl;
        } u_ospcl;

        if (!cvtflag) {
                readtape((char *)buf);
                if (buf->c_magic != NFS_MAGIC) {
                        if (swabi(buf->c_magic) != NFS_MAGIC)
                                return (FAIL);
                        if (!Bcvt) {
                                Vprintf(stdout, "Note: Doing Byte swapping\n");
                                Bcvt = 1;
                        }
                }
                if (checksum((int *)buf) == FAIL)
                        return (FAIL);
                if (Bcvt)
                        swabst((u_char *)"8i4s31i528bi192b2i", (u_char *)buf);
                goto good;
        }
        readtape((char *)(&u_ospcl.s_ospcl));
        memset((char *)buf, 0, (long)TP_BSIZE);
        buf->c_type = u_ospcl.s_ospcl.c_type;
        buf->c_date = u_ospcl.s_ospcl.c_date;
        buf->c_ddate = u_ospcl.s_ospcl.c_ddate;
        buf->c_volume = u_ospcl.s_ospcl.c_volume;
        buf->c_tapea = u_ospcl.s_ospcl.c_tapea;
        buf->c_inumber = u_ospcl.s_ospcl.c_inumber;
        buf->c_checksum = u_ospcl.s_ospcl.c_checksum;
        buf->c_magic = u_ospcl.s_ospcl.c_magic;
        buf->c_dinode.di_mode = u_ospcl.s_ospcl.c_dinode.odi_mode;
        buf->c_dinode.di_nlink = u_ospcl.s_ospcl.c_dinode.odi_nlink;
        buf->c_dinode.di_uid = u_ospcl.s_ospcl.c_dinode.odi_uid;
        buf->c_dinode.di_gid = u_ospcl.s_ospcl.c_dinode.odi_gid;
        buf->c_dinode.di_size = u_ospcl.s_ospcl.c_dinode.odi_size;
        buf->c_dinode.di_rdev = u_ospcl.s_ospcl.c_dinode.odi_rdev;
#ifdef  __linux__
        buf->c_dinode.di_atime.tv_sec = u_ospcl.s_ospcl.c_dinode.odi_atime;
        buf->c_dinode.di_mtime.tv_sec = u_ospcl.s_ospcl.c_dinode.odi_mtime;
        buf->c_dinode.di_ctime.tv_sec = u_ospcl.s_ospcl.c_dinode.odi_ctime;
#else   /* __linux__ */
        buf->c_dinode.di_atime = u_ospcl.s_ospcl.c_dinode.odi_atime;
        buf->c_dinode.di_mtime = u_ospcl.s_ospcl.c_dinode.odi_mtime;
        buf->c_dinode.di_ctime = u_ospcl.s_ospcl.c_dinode.odi_ctime;
#endif  /* __linux__ */
        buf->c_count = u_ospcl.s_ospcl.c_count;
        memmove(buf->c_addr, u_ospcl.s_ospcl.c_addr, (long)256);
        if (u_ospcl.s_ospcl.c_magic != OFS_MAGIC ||
            checksum((int *)(&u_ospcl.s_ospcl)) == FAIL)
                return(FAIL);
        buf->c_magic = NFS_MAGIC;

good:
        if ((buf->c_dinode.di_size == 0 || buf->c_dinode.di_size > 0xfffffff) &&
            (buf->c_dinode.di_mode & IFMT) == IFDIR && Qcvt == 0) {
                qcvt.qval = buf->c_dinode.di_size;
                if (qcvt.val[0] || qcvt.val[1]) {
                        printf("Note: Doing Quad swapping\n");
                        Qcvt = 1;
                }
        }
        if (Qcvt) {
                qcvt.qval = buf->c_dinode.di_size;
                i = qcvt.val[1];
                qcvt.val[1] = qcvt.val[0];
                qcvt.val[0] = i;
                buf->c_dinode.di_size = qcvt.qval;
        }
        readmapflag = 0;

        switch (buf->c_type) {

        case TS_CLRI:
        case TS_BITS:
                /*
                 * Have to patch up missing information in bit map headers
                 */
                buf->c_inumber = 0;
                buf->c_dinode.di_size = buf->c_count * TP_BSIZE;
                if (buf->c_count > TP_NINDIR)
                        readmapflag = 1;
                else 
                        for (i = 0; i < buf->c_count; i++)
                                buf->c_addr[i]++;
                break;

        case TS_TAPE:
                if ((buf->c_flags & DR_NEWINODEFMT) == 0)
                        oldinofmt = 1;
                /* fall through */
        case TS_END:
                buf->c_inumber = 0;
                break;

        case TS_INODE:
        case TS_ADDR:
                break;

        default:
                panic("gethead: unknown inode type %d\n", buf->c_type);
                break;
        }
        /*
         * If we are restoring a filesystem with old format inodes,
         * copy the uid/gid to the new location.
         */
        if (oldinofmt) {
                buf->c_dinode.di_uid = buf->c_dinode.di_ouid;
                buf->c_dinode.di_gid = buf->c_dinode.di_ogid;
        }
        if (dflag)
                accthdr(buf);
        return(GOOD);
}

/*
 * Check that a header is where it belongs and predict the next header
 */
static void
accthdr(struct s_spcl *header)
{
        static ino_t previno = 0x7fffffff;
        static int prevtype;
        static long predict;
        long blks, i;

        if (header->c_type == TS_TAPE) {
                fprintf(stderr, "Volume header (%s inode format) ",
                    oldinofmt ? "old" : "new");
                if (header->c_firstrec)
                        fprintf(stderr, "begins with record %d",
                                header->c_firstrec);
                fprintf(stderr, "\n");
                previno = 0x7fffffff;
                return;
        }
        if (previno == 0x7fffffff)
                goto newcalc;
        switch (prevtype) {
        case TS_BITS:
                fprintf(stderr, "Dumped inodes map header");
                break;
        case TS_CLRI:
                fprintf(stderr, "Used inodes map header");
                break;
        case TS_INODE:
                fprintf(stderr, "File header, ino %lu", (unsigned long)previno);
                break;
        case TS_ADDR:
                fprintf(stderr, "File continuation header, ino %ld", (long)previno);
                break;
        case TS_END:
                fprintf(stderr, "End of tape header");
                break;
        }
        if (predict != blksread - 1)
                fprintf(stderr, "; predicted %ld blocks, got %ld blocks",
                        predict, blksread - 1);
        fprintf(stderr, "\n");
newcalc:
        blks = 0;
        if (header->c_type != TS_END)
                for (i = 0; i < header->c_count; i++)
                        if (readmapflag || header->c_addr[i] != 0)
                                blks++;
        predict = blks;
        blksread = 0;
        prevtype = header->c_type;
        previno = header->c_inumber;
}

/*
 * Find an inode header.
 * Complain if had to skip, and complain is set.
 */
static void
findinode(struct s_spcl *header)
{
        static long skipcnt = 0;
        long i;
        char buf[TP_BSIZE];

        curfile.name = "<name unknown>";
        curfile.action = UNKNOWN;
        curfile.dip = NULL;
        curfile.ino = 0;
        do {
                if (header->c_magic != NFS_MAGIC) {
                        skipcnt++;
                        while (gethead(header) == FAIL ||
                            header->c_date != dumpdate)
                                skipcnt++;
                }
                switch (header->c_type) {

                case TS_ADDR:
                        /*
                         * Skip up to the beginning of the next record
                         */
                        for (i = 0; i < header->c_count; i++)
                                if (header->c_addr[i])
                                        readtape(buf);
                        while (gethead(header) == FAIL ||
                            header->c_date != dumpdate)
                                skipcnt++;
                        break;

                case TS_INODE:
                        curfile.dip = &header->c_dinode;
                        curfile.ino = header->c_inumber;
                        break;

                case TS_END:
                        curfile.ino = maxino;
                        break;

                case TS_CLRI:
                        curfile.name = "<file removal list>";
                        break;

                case TS_BITS:
                        curfile.name = "<file dump list>";
                        break;

                case TS_TAPE:
                        panic("unexpected tape header\n");
                        /* NOTREACHED */

                default:
                        panic("unknown tape header type %d\n", spcl.c_type);
                        /* NOTREACHED */

                }
        } while (header->c_type == TS_ADDR);
        if (skipcnt > 0)
                fprintf(stderr, "resync restore, skipped %ld blocks\n",
                    skipcnt);
        skipcnt = 0;
}

static int
checksum(int *buf)
{
        register int i, j;

        j = sizeof(union u_spcl) / sizeof(int);
        i = 0;
        if(!Bcvt) {
                do
                        i += *buf++;
                while (--j);
        } else {
                /* What happens if we want to read restore tapes
                        for a 16bit int machine??? */
                do
                        i += swabi(*buf++);
                while (--j);
        }

        if (i != CHECKSUM) {
                fprintf(stderr, "Checksum error %o, inode %lu file %s\n", i,
                        (unsigned long)curfile.ino, curfile.name);
                return(FAIL);
        }
        return(GOOD);
}

#ifdef RRESTORE
#ifdef __STDC__
#include <stdarg.h>
#else
#include <varargs.h>
#endif

void
#ifdef __STDC__
msg(const char *fmt, ...)
#else
msg(fmt, va_alist)
        char *fmt;
        va_dcl
#endif
{
        va_list ap;
#ifdef __STDC__
        va_start(ap, fmt);
#else
        va_start(ap);
#endif
        (void)vfprintf(stderr, fmt, ap);
        va_end(ap);
}
#endif /* RRESTORE */

static u_char *
swab16(u_char *sp, int n)
{
        char c;

        while (--n >= 0) {
                c = sp[0]; sp[0] = sp[1]; sp[1] = c;
                sp += 2;
        }
        return (sp);
}

static u_char *
swab32(u_char *sp, int n)
{
        char c;

        while (--n >= 0) {
                c = sp[0]; sp[0] = sp[3]; sp[3] = c;
                c = sp[1]; sp[1] = sp[2]; sp[2] = c;
                sp += 4;
        }
        return (sp);
}

static u_char *
swab64(u_char *sp, int n)
{
        char c;

        while (--n >= 0) {
                c = sp[0]; sp[0] = sp[7]; sp[7] = c;
                c = sp[1]; sp[1] = sp[6]; sp[6] = c;
                c = sp[2]; sp[2] = sp[5]; sp[5] = c;
                c = sp[3]; sp[3] = sp[4]; sp[4] = c;
                sp += 8;
        }
        return (sp);
}

void
swabst(u_char *cp, u_char *sp)
{
        int n = 0;

        while (*cp) {
                switch (*cp) {
                case '0': case '1': case '2': case '3': case '4':
                case '5': case '6': case '7': case '8': case '9':
                        n = (n * 10) + (*cp++ - '0');
                        continue;

                case 's': case 'w': case 'h':
                        if (n == 0)
                                n = 1;
                        sp = swab16(sp, n);
                        break;

                case 'i':
                        if (n == 0)
                                n = 1;
                        sp = swab32(sp, n);
                        break;

                case 'l':
                        if (n == 0)
                                n = 1;
                        sp = swab64(sp, n);
                        break;

                default: /* Any other character, like 'b' counts as byte. */
                        if (n == 0)
                                n = 1;
                        sp += n;
                        break;
                }
                cp++;
                n = 0;
        }
}

static u_int
swabi(u_int x)
{
        swabst((u_char *)"i", (u_char *)&x);
        return (x);
}

#if 0
static u_long
swabl(u_long x)
{
        swabst((u_char *)"l", (u_char *)&x);
        return (x);
}
#endif