Regenerate configure.

[dump.git] / dump / 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 <stelian@popies.net>, 1999-2000
 *      Stelian Pop <stelian@popies.net> - Alcôve <www.alcove.com>, 2000-2002
 */

/*-
 * Copyright (c) 1980, 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.
 */

#ifndef lint
static const char rcsid[] =
        "$Id: tape.c,v 1.96 2011/06/10 13:41:41 stelian Exp $";
#endif /* not lint */

#include <config.h>
#include <compatlfs.h>
#include <errno.h>
#include <fcntl.h>
#include <setjmp.h>
#include <signal.h>
#include <stdio.h>
#include <compaterr.h>
#include <system.h>
#ifdef __STDC__
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#else
int    write(), read();
#endif

#ifdef __linux__
#include <sys/types.h>
#include <sys/time.h>
#include <sys/ioctl.h>
#include <sys/mount.h>  /* for definition of BLKFLSBUF */
#ifndef BLKFLSBUF       /* last resort... */
#define BLKFLSBUF _IO(0x12, 97) /* Flush buffer cache.  */
#endif
#include <time.h>
#endif
#include <sys/param.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <sys/mtio.h>
#ifdef __linux__
#ifdef HAVE_EXT2FS_EXT2_FS_H
#include <ext2fs/ext2_fs.h>
#else
#include <linux/ext2_fs.h>
#endif
#include <ext2fs/ext2fs.h>
#include <sys/stat.h>
#include <bsdcompat.h>
#elif defined sunos
#include <sys/vnode.h>

#include <ufs/fs.h>
#include <ufs/inode.h>
#else
#include <ufs/ufs/dinode.h>
#include <ufs/ffs/fs.h>
#endif  /* __linux__ */

#include <protocols/dumprestore.h>

#include "dump.h"
#include "indexer.h"
#include "slave.h"

int     writesize;              /* size of malloc()ed buffer for tape */
long    lastspclrec = -1;       /* tape block number of last written header */
int     trecno = 0;             /* next record to write in current block */
extern  long *blocksperfiles;   /* number of blocks per output file(s) */
long    blocksperfiles_current; /* current position in blocksperfiles */
long    blocksthisvol;          /* number of blocks on current output file */
extern  int ntrec;              /* blocking factor on tape */
extern  int cartridge;
char    *nexttape;
extern  pid_t rshpid;
int     eot_code = 1;
long long tapea_bytes = 0;      /* bytes_written at start of current volume */
static int magtapeout;          /* output is really a tape */

static  ssize_t dump_atomic_read __P((int, char *, size_t));
static  ssize_t dump_atomic_write __P((int, const char *, size_t));
#ifdef WRITEDEBUG
static  void doslave __P((int, int, int));
#else
static  void doslave __P((int, int));
#endif
static  void enslave __P((void));
static  void flushtape __P((void));
static  void killall __P((void));
static  void rollforward __P((void));

int reqsiz;

struct slave_results {
        ssize_t unclen;         /* uncompressed length */
        ssize_t clen;           /* compressed length */
};

struct slave slaves[SLAVES+1];
struct slave *slp;

char    (*nextblock)[TP_BSIZE];

static time_t tstart_volume;    /* time of volume start */ 
static int tapea_volume;        /* value of spcl.c_tapea at volume start */

int master;             /* pid of master, for sending error signals */
int tenths;             /* length of tape overhead per block written */
static int caught1;     /* have we caught the signal to proceed? */
static int ready1;      /* have we reached the lock point without having */
                        /* received the SIGUSR2 signal from the prev slave? */
static sigjmp_buf jmpbuf1;      /* where to jump to if we are ready when the */
                        /* SIGUSR1 arrives from the previous slave */
static int caught2;     /* have we caught the signal to proceed? */
static int ready2;      /* have we reached the lock point without having */
                        /* received the SIGUSR2 signal from the prev slave? */
static sigjmp_buf jmpbuf2;      /* where to jump to if we are ready when the */
                        /* SIGUSR2 arrives from the previous slave */

/*
 * Determine if we can use Linux' clone system call.  If so, call it
 * with the CLONE_IO flag so that all processes will share the same I/O
 * context, allowing the I/O schedulers to make better scheduling decisions.
 */
#ifdef __linux__
/* first, pull in the header files that define sys_clone and CLONE_IO */
#include <syscall.h>
#define _GNU_SOURCE
#include <sched.h>
#include <unistd.h>
#undef _GNU_SOURCE

/* If either is not present, fall back on the fork behaviour */
#if ! defined(SYS_clone) || ! defined (CLONE_IO)
#define fork_clone_io fork
#else /* SYS_clone */
/* CLONE_IO is available, determine which version of sys_clone to use */
#include <linux/version.h>
/*
 * Kernel 2.5.49 introduced two extra parameters to the clone system call.
 * Neither is useful in our case, so this is easy to handle.
 */
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,5,49)
/*
 * Parameters of the sys_clone syscall are
 * clone_flags, child_stack, parent_tidptr, child_tidptr
 * on all architectures except s390 and s390x
 * s390* have child_stack, clone_flags, parent_tidptr, child_tidptr
 */
#if defined(__s390__) || defined(__s390x__)
#define CLONE_ARGS 0, SIGCHLD|CLONE_IO, NULL, NULL
#else
#define CLONE_ARGS SIGCHLD|CLONE_IO, 0, NULL, NULL
#endif
#else
#define CLONE_ARGS SIGCHLD|CLONE_IO, 0
#endif /* LINUX_VERSION_CODE */
pid_t fork_clone_io(void);
#endif /* SYS_clone */
#else /* __linux__ not defined */
#define fork_clone_io fork
#endif /* __linux__ */

int
alloctape(void)
{
        int pgoff = getpagesize() - 1;
        char *buf;
        int i;

        writesize = ntrec * TP_BSIZE;
        reqsiz = (ntrec + 1) * sizeof(struct req);
        /*
         * CDC 92181's and 92185's make 0.8" gaps in 1600-bpi start/stop mode
         * (see DEC TU80 User's Guide).  The shorter gaps of 6250-bpi require
         * repositioning after stopping, i.e, streaming mode, where the gap is
         * variable, 0.30" to 0.45".  The gap is maximal when the tape stops.
         */
        if (!blocksperfiles && !unlimited)
                tenths = (cartridge ? 16 : density == 625 ? 5 : 8);
        else {
                tenths = 0;
                density = 1;
        }
        /*
         * Allocate tape buffer contiguous with the array of instruction
         * packets, so flushtape() can write them together with one write().
         * Align tape buffer on page boundary to speed up tape write().
         */
        for (i = 0; i <= SLAVES; i++) {
                buf = (char *)
                    malloc((unsigned)(reqsiz + writesize + pgoff + TP_BSIZE));
                if (buf == NULL)
                        return(0);
                slaves[i].tblock = (char (*)[TP_BSIZE])
#ifdef  __linux__
                    (((long)&buf[reqsiz] + pgoff) &~ pgoff);
#else
                    (((long)&buf[ntrec + 1] + pgoff) &~ pgoff);
#endif
                slaves[i].req = (struct req *)slaves[i].tblock - ntrec - 1;
        }
        slp = &slaves[0];
        slp->count = 1;
        slp->tapea = 0;
        slp->firstrec = 0;
        nextblock = slp->tblock;
        return(1);
}

void
writerec(const void *dp, int isspcl)
{
        slp->req[trecno].dblk = (ext2_loff_t)0;
        slp->req[trecno].count = 1;
        /* XXX post increment triggers an egcs-1.1.2-12 bug on alpha/sparc */
        *(union u_spcl *)(*(nextblock)) = *(union u_spcl *)dp;

        /* Need to write it to the archive file */
        indexer->writerec(dp, isspcl);

        nextblock++;
        if (isspcl)
                lastspclrec = spcl.c_tapea;
        trecno++;
        spcl.c_tapea++;
        if (trecno >= ntrec)
                flushtape();
}

void
dumpblock(blk_t blkno, int size)
{
        int avail, tpblks;
        ext2_loff_t dblkno;

        dblkno = fsbtodb(sblock, blkno);
        tpblks = size >> tp_bshift;
        while ((avail = MIN(tpblks, ntrec - trecno)) > 0) {
                slp->req[trecno].dblk = dblkno;
                slp->req[trecno].count = avail;
                trecno += avail;
                spcl.c_tapea += avail;
                if (trecno >= ntrec)
                        flushtape();
                dblkno += avail << (tp_bshift - dev_bshift);
                tpblks -= avail;
        }
}

int     nogripe = 0;

static void
tperror(int errnum)
{

        if (pipeout) {
                msg("write error on %s: %s\n", tape, strerror(errnum));
                quit("Cannot recover\n");
                /* NOTREACHED */
        }
        msg("write error %d blocks into volume %d: %s\n", 
            blocksthisvol, tapeno, strerror(errnum));
        broadcast("DUMP WRITE ERROR!\n");
        if (query("Do you want to rewrite this volume?")) {
                msg("Closing this volume.  Prepare to restart with new media;\n");
                msg("this dump volume will be rewritten.\n");
                killall();
                nogripe = 1;
                close_rewind();
                Exit(X_REWRITE);
        }
        if (query("Do you want to start the next tape?"))
                return;
        dumpabort(0);
}

static void
sigpipe(UNUSED(int signo))
{

        quit("Broken pipe\n");
}

/*
 * do_stats --
 *     Update xferrate stats
 */
time_t
do_stats(void)
{
        time_t tnow, ttaken;
        int blocks;

        tnow = time(NULL);
        ttaken = tnow - tstart_volume;
        blocks = spcl.c_tapea - tapea_volume;
        msg("Volume %d completed at: %s", tapeno, ctime(&tnow));
        if (! compressed)
                msg("Volume %d %ld blocks (%.2fMB)\n", tapeno, 
                        blocks, ((double)blocks * TP_BSIZE / 1048576));
        if (ttaken > 0) {
                long volkb = (bytes_written - tapea_bytes) / 1024;
                long txfrate = volkb / ttaken;
                msg("Volume %d took %d:%02d:%02d\n", tapeno,
                        ttaken / 3600, (ttaken % 3600) / 60, ttaken % 60);
                msg("Volume %d transfer rate: %ld kB/s\n", tapeno,
                        txfrate);
                xferrate += txfrate;
                if (compressed) {
                        double rate = .0005 + (double) blocks / (double) volkb;
                        msg("Volume %d %ldkB uncompressed, %ldkB compressed,"
                                " %1.3f:1\n",
                                tapeno, blocks, volkb, rate);
                }
        }
        return(tnow);
}

char *
mktimeest(time_t tnow)
{
        static char msgbuf[128];
        time_t deltat;

        msgbuf[0] = '\0';

        if (blockswritten < 500)
                return NULL;
        if (blockswritten > tapesize)
                tapesize = blockswritten;
        deltat = tstart_writing - tnow + (1.0 * (tnow - tstart_writing))
                / blockswritten * tapesize;
        if (tnow > tstart_volume)
                (void)snprintf(msgbuf, sizeof(msgbuf),
                        "%3.2f%% done at %ld kB/s, finished in %d:%02d\n",
                        (blockswritten * 100.0) / tapesize,
                        (spcl.c_tapea - tapea_volume) / (tnow - tstart_volume),
                        (int)(deltat / 3600), (int)((deltat % 3600) / 60));
        else
                (void)snprintf(msgbuf, sizeof(msgbuf),
                        "%3.2f%% done, finished in %d:%02d\n",
                        (blockswritten * 100.0) / tapesize,
                        (int)(deltat / 3600), (int)((deltat % 3600) / 60));

        return msgbuf;
}

#if defined(SIGINFO)
/*
 * statussig --
 *     information message upon receipt of SIGINFO
 */
void
statussig(int notused)
{
        int save_errno = errno;
        char *buf;

        buf = mktimeest(time(NULL));
        if (buf)
                write(STDERR_FILENO, buf, strlen(buf));
        errno = save_errno;
}
#endif

static void
flushtape(void)
{
        int i, blks, got;
        long lastfirstrec;
        struct slave_results returned;

        int siz = (char *)nextblock - (char *)slp->req;

        /* make sure returned has sane values in case we don't read 
         * them from the slave in this pass */
        returned.unclen = returned.clen = writesize;

        slp->req[trecno].count = 0;                     /* Sentinel */

        if (dump_atomic_write( slp->fd, (char *)slp->req, siz) != siz)
                quit("error writing command pipe: %s\n", strerror(errno));
        slp->sent = 1; /* we sent a request, read the response later */

        lastfirstrec = slp->firstrec;

        if (++slp >= &slaves[SLAVES])
                slp = &slaves[0];

        /* Read results back from next slave */
        if (slp->sent) {
                if (dump_atomic_read( slp->fd, (char *)&returned, sizeof returned)
                    != sizeof returned) {
                        perror("  DUMP: error reading command pipe in master");
                        dumpabort(0);
                }
                got = returned.unclen;
                bytes_written += returned.clen;
                if (returned.unclen == returned.clen)
                        uncomprblks++;
                slp->sent = 0;

                /* Check for errors or end of tape */
                if (got <= 0) {
                        /* Check for errors */
                        if (got < 0)
                                tperror(-got);
                        else
                                msg("End of tape detected\n");

                        /*
                         * Drain the results, don't care what the values were.
                         * If we read them here then trewind won't...
                         */
                        for (i = 0; i < SLAVES; i++) {
                                if (slaves[i].sent) {
                                        if (dump_atomic_read( slaves[i].fd,
                                            (char *)&returned, sizeof returned)
                                            != sizeof returned) {
                                                perror("  DUMP: error reading command pipe in master");
                                                dumpabort(0);
                                        }
                                        slaves[i].sent = 0;
                                }
                        }

                        close_rewind();
                        rollforward();
                        return;
                }
        }

        blks = 0;
        if (spcl.c_type == TS_CLRI || spcl.c_type == TS_BITS)
                blks = spcl.c_count;
        else {
                if (spcl.c_type != TS_END) {
                        for (i = 0; i < spcl.c_count; i++)
                                if (spcl.c_addr[i] != 0)
                                        blks++;
                }
        }
        slp->count = lastspclrec + blks + 1 - spcl.c_tapea;
        slp->tapea = spcl.c_tapea;
        slp->firstrec = lastfirstrec + ntrec;
        slp->inode = curino;
        nextblock = slp->tblock;
        trecno = 0;
        asize += tenths + returned.clen / density;
        blockswritten += ntrec;
        blocksthisvol += ntrec;
        if (!pipeout && !unlimited) {
                if (blocksperfiles && blocksperfiles[blocksperfiles_current]) {
                        if ( compressed ? (bytes_written - tapea_bytes + SLAVES * (writesize + sizeof(struct tapebuf))) >= (((long long)blocksperfiles[blocksperfiles_current]) * 1024)
                                        : blocksthisvol >= blocksperfiles[blocksperfiles_current] ) {
                                close_rewind();
                                startnewtape(0);
                        }
                }
                else if (asize > tsize) {
                        close_rewind();
                        startnewtape(0);
                }
        }
        timeest();
}

time_t
trewind(void)
{
        int f;
        int got;
        struct slave_results returned;

        for (f = 0; f < SLAVES; f++) {
                /*
                 * Drain the results, but unlike EOT we DO (or should) care
                 * what the return values were, since if we detect EOT after
                 * we think we've written the last blocks to the tape anyway,
                 * we have to replay those blocks with rollforward.
                 *
                 * fixme: punt for now.
                 */
                if (slaves[f].sent) {
                        if (dump_atomic_read( slaves[f].fd, (char *)&returned, sizeof returned)
                            != sizeof returned) {
                                perror("  DUMP: error reading command pipe in master");
                                dumpabort(0);
                        }
                        got = returned.unclen;
                        bytes_written += returned.clen;
                        if (returned.unclen == returned.clen)
                                uncomprblks++;
                        slaves[f].sent = 0;

                        if (got < 0)
                                tperror(-got);

                        if (got == 0) {
                                msg("EOT detected in last 2 tape records!\n");
                                msg("Use a longer tape, decrease the size estimate\n");
                                quit("or use no size estimate at all.\n");
                        }
                }
                (void) close(slaves[f].fd);
        }
        while (wait((int *)NULL) >= 0)  /* wait for any signals from slaves */
                /* void */;

        if (!pipeout) {

                msg("Closing %s\n", tape);

#ifdef RDUMP
                if (host) {
                        rmtclose();
                        while (rmtopen(tape, O_RDONLY) < 0)
                                sleep(10);
                        rmtclose();
                }
                else 
#endif
                {
                        (void) close(tapefd);
                        if (!fifoout) {
                                while ((f = OPEN(tape, O_RDONLY)) < 0)
                                        sleep (10);
                                (void) close(f);
                        }
                }
        }
        return do_stats();
}

                
void
close_rewind(void)
{
        int eot_code = 1;
        (void)trewind();
        if (eot_script) {
                msg("Launching %s\n", eot_script);
                eot_code = system_command(eot_script, tape, tapeno);
        }
        if (eot_code != 0 && eot_code != 1) {
                msg("Dump aborted by the end of tape script\n");
                dumpabort(0);
        }
        if (eot_code == 0)
                return;
        if (nexttape || Mflag)
                return;
        if (!nogripe) {
                msg("Change Volumes: Mount volume #%d\n", tapeno+1);
                broadcast("CHANGE DUMP VOLUMES!\7\7\n");
        }
        while (!query("Is the new volume mounted and ready to go?"))
                if (query("Do you want to abort?")) {
                        dumpabort(0);
                        /*NOTREACHED*/
                }
}

void
rollforward(void)
{
        struct req *p, *q = NULL, *prev;
        struct slave *tslp;
        int i, size, savedtapea, got;
        union u_spcl *ntb, *otb;
        struct slave_results returned;
#ifdef __linux__
        int blks;
        long lastfirstrec;
#endif
        tslp = &slaves[SLAVES];
        ntb = (union u_spcl *)tslp->tblock[1];

        /* make sure returned has sane values in case we don't read 
         * them from the slave in this pass */
        returned.unclen = returned.clen = writesize;

        /*
         * Each of the N slaves should have requests that need to
         * be replayed on the next tape.  Use the extra slave buffers
         * (slaves[SLAVES]) to construct request lists to be sent to
         * each slave in turn.
         */
        for (i = 0; i < SLAVES; i++) {
                q = &tslp->req[1];
                otb = (union u_spcl *)slp->tblock;

                /*
                 * For each request in the current slave, copy it to tslp.
                 */

                prev = NULL;
                for (p = slp->req; p->count > 0; p += p->count) {
                        *q = *p;
                        if (p->dblk == 0)
                                *ntb++ = *otb++; /* copy the datablock also */
                        prev = q;
                        q += q->count;
                }
                if (prev == NULL)
                        quit("rollforward: protocol botch");
                if (prev->dblk != 0)
                        prev->count -= 1;
                else
                        ntb--;
                q -= 1;
                q->count = 0;
                q = &tslp->req[0];
                if (i == 0) {
                        q->dblk = 0;
                        q->count = 1;
                        trecno = 0;
                        nextblock = tslp->tblock;
                        savedtapea = spcl.c_tapea;
                        spcl.c_tapea = slp->tapea;
                        startnewtape(0);
                        spcl.c_tapea = savedtapea;
                        lastspclrec = savedtapea - 1;
                }
                size = (char *)ntb - (char *)q;
                if (dump_atomic_write( slp->fd, (char *)q, size) != size) {
                        perror("  DUMP: error writing command pipe");
                        dumpabort(0);
                }
                slp->sent = 1;
#ifdef __linux__
                lastfirstrec = slp->firstrec;
#endif
                if (++slp >= &slaves[SLAVES])
                        slp = &slaves[0];

                q->count = 1;

                if (prev->dblk != 0) {
                        /*
                         * If the last one was a disk block, make the
                         * first of this one be the last bit of that disk
                         * block...
                         */
                        q->dblk = prev->dblk +
                                prev->count * (TP_BSIZE / DEV_BSIZE);
                        ntb = (union u_spcl *)tslp->tblock;
                } else {
                        /*
                         * It wasn't a disk block.  Copy the data to its
                         * new location in the buffer.
                         */
                        q->dblk = 0;
                        *((union u_spcl *)tslp->tblock) = *ntb;
                        ntb = (union u_spcl *)tslp->tblock[1];
                }
        }
        slp->req[0] = *q;
        nextblock = slp->tblock;
        if (q->dblk == 0) {
#ifdef __linux__
        /* XXX post increment triggers an egcs-1.1.2-12 bug on alpha/sparc */
                *(union u_spcl *)(*nextblock) = *(union u_spcl *)tslp->tblock;
#endif
                nextblock++;
        }
        trecno = 1;

        /*
         * Clear the first slaves' response.  One hopes that it
         * worked ok, otherwise the tape is much too short!
         */
        if (slp->sent) {
                if (dump_atomic_read( slp->fd, (char *)&returned, sizeof returned)
                    != sizeof returned) {
                        perror("  DUMP: error reading command pipe in master");
                        dumpabort(0);
                }
                got = returned.unclen;
                bytes_written += returned.clen;
                if (returned.clen == returned.unclen)
                        uncomprblks++;
                slp->sent = 0;

                if (got < 0)
                        tperror(-got);

                if (got == 0) {
                        quit("EOT detected at start of the tape!\n");
                }
        }

#ifdef __linux__
        blks = 0;
        if (spcl.c_type != TS_END) {
                for (i = 0; i < spcl.c_count; i++)
                        if (spcl.c_addr[i] != 0)
                                blks++;
        }

        slp->firstrec = lastfirstrec + ntrec;
        slp->count = lastspclrec + blks + 1 - spcl.c_tapea;
        slp->inode = curino;
        asize += tenths + returned.clen / density;
        blockswritten += ntrec;
        blocksthisvol += ntrec;
#endif
}

#ifdef __linux__
#if defined(SYS_clone) && defined(CLONE_IO)
pid_t
fork_clone_io(void)
{
        return syscall(SYS_clone, CLONE_ARGS);
}
#endif
#endif

/*
 * We implement taking and restoring checkpoints on the tape level.
 * When each tape is opened, a new process is created by forking; this
 * saves all of the necessary context in the parent.  The child
 * continues the dump; the parent waits around, saving the context.
 * If the child returns X_REWRITE, then it had problems writing that tape;
 * this causes the parent to fork again, duplicating the context, and
 * everything continues as if nothing had happened.
 */
void
startnewtape(int top)
{
        int     parentpid;
        int     childpid;
        int     status;
        int     waitpid;
        char    *p;

#ifdef  __linux__
        sigset_t sigs;
        sigemptyset(&sigs);
        sigaddset(&sigs, SIGINT);
        sigprocmask(SIG_BLOCK, &sigs, NULL);
#else   /* __linux__ */
#ifdef sunos
        void    (*interrupt_save)();
#else
        sig_t   interrupt_save;
#endif
        interrupt_save = signal(SIGINT, SIG_IGN);
#endif  /* __linux__ */

        parentpid = getpid();
        tapea_volume = spcl.c_tapea;
        tapea_bytes = bytes_written;
        tstart_volume = time(NULL);

restore_check_point:
#ifdef  __linux__
        sigprocmask(SIG_UNBLOCK, &sigs, NULL);
#else
        (void)signal(SIGINT, interrupt_save);
#endif
        /*
         *      All signals are inherited...
         */
        childpid = fork_clone_io();
        if (childpid < 0) {
                msg("Context save fork fails in parent %d\n", parentpid);
                Exit(X_ABORT);
        }
        if (childpid != 0) {
                /*
                 *      PARENT:
                 *      save the context by waiting
                 *      until the child doing all of the work returns.
                 *      don't catch the interrupt
                 */
#ifdef  __linux__
                sigprocmask(SIG_BLOCK, &sigs, NULL);
#else
                signal(SIGINT, SIG_IGN);
#endif
#ifdef TDEBUG
                msg("Tape: %d; parent process: %d child process %d\n",
                        tapeno+1, parentpid, childpid);
#endif /* TDEBUG */
                while ((waitpid = wait(&status)) != childpid)
                        if (waitpid != rshpid)
                                msg("Parent %d waiting for child %d has another child %d return\n",
                                parentpid, childpid, waitpid);
                if (status & 0xFF) {
                        msg("Child %d returns LOB status %o\n",
                                childpid, status&0xFF);
                }
                status = (status >> 8) & 0xFF;
#ifdef TDEBUG
                switch(status) {
                        case X_FINOK:
                                msg("Child %d finishes X_FINOK\n", childpid);
                                break;
                        case X_ABORT:
                                msg("Child %d finishes X_ABORT\n", childpid);
                                break;
                        case X_REWRITE:
                                msg("Child %d finishes X_REWRITE\n", childpid);
                                break;
                        default:
                                msg("Child %d finishes unknown %d\n",
                                        childpid, status);
                                break;
                }
#endif /* TDEBUG */
                switch(status) {
                        case X_FINOK:
                                Exit(X_FINOK);
                        case X_ABORT:
                                Exit(X_ABORT);
                        case X_REWRITE:
                                goto restore_check_point;
                        default:
                                msg("Bad return code from dump: %d\n", status);
                                Exit(X_ABORT);
                }
                /*NOTREACHED*/
        } else {        /* we are the child; just continue */
#ifdef TDEBUG
                sleep(4);       /* allow time for parent's message to get out */
                msg("Child on Tape %d has parent %d, my pid = %d\n",
                        tapeno+1, parentpid, getpid());
#endif /* TDEBUG */
                /*
                 * If we have a name like "/dev/rmt0,/dev/rmt1",
                 * use the name before the comma first, and save
                 * the remaining names for subsequent volumes.
                 */
                tapeno++;               /* current tape sequence */
                if (Mflag) {
                        snprintf(tape, MAXPATHLEN, "%s%03d", tapeprefix, tapeno);
                        tape[MAXPATHLEN - 1] = '\0';
                        msg("Dumping volume %d on %s\n", tapeno, tape);
                }
                else if (nexttape || strchr(tapeprefix, ',')) {
                        if (nexttape && *nexttape)
                                tapeprefix = nexttape;
                        if ((p = strchr(tapeprefix, ',')) != NULL) {
                                *p = '\0';
                                nexttape = p + 1;
                        } else
                                nexttape = NULL;
                        strncpy(tape, tapeprefix, MAXPATHLEN);
                        tape[MAXPATHLEN - 1] = '\0';
                        msg("Dumping volume %d on %s\n", tapeno, tape);
                }
                if (blocksperfiles && blocksperfiles_current < *blocksperfiles)
                        blocksperfiles_current++;
#ifdef RDUMP
                while ((tapefd = (host ? rmtopen(tape, O_WRONLY|O_CREAT|O_TRUNC) : pipeout ? 
                        fileno(stdout) : 
                        OPEN(tape, O_WRONLY|O_CREAT|O_TRUNC, 0666))) < 0)
#else
                while ((tapefd = (pipeout ? fileno(stdout) :
                                  OPEN(tape, O_WRONLY|O_CREAT|O_TRUNC, 0666))) < 0)
#endif
                    {
                        msg("Cannot open output \"%s\": %s\n", tape, 
                            strerror(errno));
                        if (!query("Do you want to retry the open?"))
                                dumpabort(0);
                }
#ifdef RDUMP
                if (!host)
#endif
                        {
                                struct mtget mt_stat;
                                magtapeout = ioctl(tapefd, MTIOCGET, (char *)&mt_stat) == 0;
                                /*
                                msg("Output is to %s\n", 
                                        magtapeout ? "tape" : "file/pipe");
                                */
                        }

                enslave();  /* Share open tape file descriptor with slaves */

                asize = 0;
                blocksthisvol = 0;
                if (top)
                        newtape++;              /* new tape signal */
                spcl.c_count = slp->count;
                /*
                 * measure firstrec in TP_BSIZE units since restore doesn't
                 * know the correct ntrec value...
                 */
                spcl.c_firstrec = slp->firstrec;
                spcl.c_volume++;
                spcl.c_type = TS_TAPE;
                spcl.c_flags |= DR_NEWHEADER;
                spcl.c_ntrec = ntrec;
                if (compressed)
                        spcl.c_flags |= DR_COMPRESSED;
                writeheader((dump_ino_t)slp->inode);
                spcl.c_flags &=~ DR_NEWHEADER;
                msg("Volume %d started with block %ld at: %s", tapeno, 
                    spcl.c_tapea, ctime(&tstart_volume));
                if (tapeno > 1)
                        msg("Volume %d begins with blocks from inode %d\n",
                                tapeno, slp->inode);
                if (tapeno < (int)TP_NINOS)
                        volinfo[tapeno] = slp->inode;
                transformation->startNewTape(transformation, NULL, 0);
        }
}

void
dumpabort(UNUSED(int signo))
{

        if (master != 0 && master != getpid())
                /* Signals master to call dumpabort */
                (void) kill(master, SIGTERM);
        else {
                killall();
                msg("The ENTIRE dump is aborted.\n");
        }
#ifdef RDUMP
        rmtclose();
#endif
        Exit(X_ABORT);
}

void
Exit(int status)
{

#ifdef TDEBUG
        msg("pid = %d exits with status %d\n", getpid(), status);
#endif /* TDEBUG */
        exit(status);
}

/*
 * proceed - handler for SIGUSR1, used to synchronize IO between the slaves.
 */
static void
proceed1(UNUSED(int signo))
{
        if (ready1)
                siglongjmp(jmpbuf1, 1);
        caught1++;
}

/*
 * proceed - handler for SIGUSR2, used to synchronize IO between the slaves.
 */
static void
proceed2(UNUSED(int signo))
{
        if (ready2)
                siglongjmp(jmpbuf2, 1);
        caught2++;
}

void
enslave(void)
{
        int cmd[2];
#ifdef  LINUX_FORK_BUG
        int i, j;
#else
        int i, j;
#endif

        master = getpid();

    {   struct sigaction sa;
        memset(&sa, 0, sizeof sa);
        sigemptyset(&sa.sa_mask);
        sa.sa_handler = dumpabort;
        sigaction(SIGTERM, &sa, NULL); /* Slave sends SIGTERM on dumpabort() */
        sa.sa_handler = sigpipe;
        sigaction(SIGPIPE, &sa, NULL);
        sa.sa_handler = proceed1;
        sa.sa_flags = SA_RESTART;
        sigaction(SIGUSR1, &sa, NULL); /* Slave sends SIGUSR1 to next slave */
        sa.sa_handler = proceed2;
        sa.sa_flags = SA_RESTART;
        sigaction(SIGUSR2, &sa, NULL); /* Slave sends SIGUSR2 to next slave */
   }

        for (i = 0; i < SLAVES; i++) {
                if (i == slp - &slaves[0]) {
                        caught1 = 1;
                        caught2 = 1;
                } else {
                        caught1 = 0;
                        caught2 = 0;
                }

                if (socketpair(AF_UNIX, SOCK_STREAM, 0, cmd) < 0 ||
                    (slaves[i].pid = fork_clone_io()) < 0)
                        quit("too many slaves, %d (recompile smaller): %s\n",
                            i, strerror(errno));

                slaves[i].fd = cmd[1];
                slaves[i].sent = 0;
                if (slaves[i].pid == 0) {           /* Slave starts up here */
                        sigset_t sigs;
                        for (j = 0; j <= i; j++)
                                (void) close(slaves[j].fd);
                        sigemptyset(&sigs);
                        sigaddset(&sigs, SIGINT);  /* Master handles this */
#if defined(SIGINFO)
                        sigaddset(&sigs, SIGINFO);
#endif
                        sigprocmask(SIG_BLOCK, &sigs, NULL);

#ifdef  LINUX_FORK_BUG
                        if (dump_atomic_write( cmd[0], (char *) &i, sizeof i)
                            != sizeof i)
                                quit("master/slave protocol botched 3\n");
#endif
                        doslave(cmd[0], 
#ifdef WRITEDEBUG
                                i, 
#endif
                                (slaves[i].pid == slp->pid));
                        Exit(X_FINOK);
                }
                else
                        close(cmd[0]);
        }

#ifdef  LINUX_FORK_BUG
        /*
         * Wait for all slaves to _actually_ start to circumvent a bug in
         * Linux kernels >= 2.1.3 where a signal sent to a child that hasn't
         * returned from fork() causes a SEGV in the child process
         */
        for (i = 0; i < SLAVES; i++)
                if (dump_atomic_read( slaves[i].fd, (char *) &j, sizeof j) != sizeof j)
                        quit("master/slave protocol botched 4\n");
#endif

        for (i = 0; i < SLAVES; i++)
                (void) dump_atomic_write( slaves[i].fd, 
                              (char *) &slaves[(i + 1) % SLAVES].pid, 
                              sizeof slaves[0].pid);
                
        master = 0; 
}

void
killall(void)
{
        int i;

        for (i = 0; i < SLAVES; i++)
                if (slaves[i].pid > 0) {
                        (void) kill(slaves[i].pid, SIGKILL);
                        slaves[i].sent = 0;
                }
}

/*
 * Synchronization - each process waits for a SIGUSR2 from the
 * previous process before writing to the tape, and sends SIGUSR2
 * to the next process when the tape write completes. On tape errors
 * a SIGUSR1 is sent to the master which then terminates all of the
 * slaves.  Each process sends SIGUSR1 to the next to signal that it
 * is time to start reading from the disk, after it finishes reading
 * and moves to the compression phase.
 */
static void
doslave(int cmd, 
#ifdef WRITEDEBUG
        int slave_number, 
#endif
        int first)
{
        int nread;
        int nextslave;
        volatile int wrote = 0, size, eot_count, bufsize;
        char * volatile buffer;
#if defined(HAVE_BLOCK_TRANSFORMATION)
        struct tapebuf * volatile comp_buf = NULL;
        int compresult;
        volatile int do_compress = !first;
        unsigned long worklen;
#endif /* HAVE_BLOCK_TRANSFORMATION */

        struct slave_results returns;
#ifdef  __linux__
        errcode_t retval;
#endif
#ifdef USE_QFA
    QFA_State qfa_state;
#endif /* USE_QFA */
        sigset_t set;

        sigemptyset(&set);
        sigaddset(&set, SIGUSR1);
        sigaddset(&set, SIGUSR2);
        sigprocmask(SIG_BLOCK, &set, NULL);
        sigemptyset(&set);

#ifdef HAVE_BLOCK_TRANSFORMATION
        transformation->startDiskIOProcess(transformation);
#endif /* HAVE_BLOCK_TRANSFORMATION */

        indexer->openQfaState(&qfa_state);

        /*
         * Need our own seek pointer.
         */
        (void) close(diskfd);
        if ((diskfd = OPEN(disk, O_RDONLY)) < 0)
                quit("slave couldn't reopen disk: %s\n", strerror(errno));
#ifdef  __linux__
#ifdef BLKFLSBUF
        (void)ioctl(diskfd, BLKFLSBUF, 0);
#endif
        ext2fs_close(fs);
        retval = dump_fs_open(disk, &fs);
        if (retval)
                quit("slave couldn't reopen disk: %s\n", error_message(retval));
#endif  /* __linux__ */

        /*
         * Need the pid of the next slave in the loop...
         */
        if ((nread = dump_atomic_read( cmd, (char *)&nextslave, sizeof nextslave))
            != sizeof nextslave) {
                quit("master/slave protocol botched - didn't get pid of next slave.\n");
        }

#if defined(HAVE_BLOCK_TRANSFORMATION)
        /* if we're doing a compressed dump, allocate the compress buffer */
        if (compressed) {
                int bsiz = sizeof(struct tapebuf) + writesize;
                /* Add extra space to deal with compression or encryption enlarging the buffer */
                if (TP_BSIZE > writesize/16 + 200)
                        bsiz += TP_BSIZE;
                else
                        bsiz += writesize/16 + 200;
                comp_buf = malloc(bsiz);
                if (comp_buf == NULL)
                        quit("couldn't allocate a compress buffer.\n");
                transformation->initialize(transformation, 1);
                if (zipflag == COMPRESS_ZLIB)
                        comp_buf->flags = COMPRESS_ZLIB;
                else if (zipflag == COMPRESS_BZLIB)
                        comp_buf->flags = COMPRESS_BZLIB;
        else if (zipflag == COMPRESS_LZO)
                        comp_buf->flags = COMPRESS_LZO;
        else
                        quit("internal error - unknown compression method: %d\n", zipflag);
        }
#endif /* HAVE_BLOCK_TRANSFORMATION */

        /*
         * Get list of blocks to dump, read the blocks into tape buffer
         */
        while ((nread = dump_atomic_read( cmd, (char *)slp->req, reqsiz)) == reqsiz) {
                struct req *p = slp->req;

                /* wait for previous slave to finish reading */
                if (sigsetjmp(jmpbuf1, 1) == 0) {
                        ready1 = 1;
                        if (!caught1)
                                sigsuspend(&set);
                }
                ready1 = 0;
                caught1 = 0;

                for (trecno = 0; trecno < ntrec;
                     trecno += p->count, p += p->count) {
                         
                        if (p->dblk) {  /* read a disk block */
                                bread(p->dblk, slp->tblock[trecno],
                                        p->count * TP_BSIZE);
                        } else {        /* read record from pipe */
                                if (p->count != 1 || dump_atomic_read( cmd,
                                    (char *)slp->tblock[trecno],
                                    TP_BSIZE) != TP_BSIZE)
                                       quit("master/slave protocol botched.\n");
                        }
                }
                /* signal next slave to start reading */
                (void) kill(nextslave, SIGUSR1);

                /* Try to write the data... */
                wrote = 0;
                eot_count = 0;
                size = 0;
                buffer = (char *) slp->tblock[0];       /* set write pointer */
                bufsize = writesize;                    /* length to write */
                returns.clen = returns.unclen = bufsize;

#if defined(HAVE_BLOCK_TRANSFORMATION)
                /* 
                 * When writing a compressed dump, each block except
                 * the first one on each tape is written
                 * from struct tapebuf with an 4 byte prefix
                 * followed by the data. This can be less than
                 * writesize. Restore, on a short read, can compare the
                 * length read to the compressed length in the header
                 * to verify that the read was good. Blocks which don't
                 * compress well are written uncompressed.
                 * The first block written by each slave is not compressed
                 * and does not have a prefix.
                 */
                if (compressed && do_compress) {
                        comp_buf->length = bufsize;
                        worklen = TP_BSIZE + writesize;
                        compresult = 1;

                        // tapebuf: compressed, flags, length
                        compresult = transformation->compress(transformation, comp_buf,
                                        &worklen, slp->tblock[0], writesize);

                        if (compresult && worklen <= ((unsigned long)writesize - 16)) {
                                /* write the compressed buffer */
                                comp_buf->length = worklen;
                                comp_buf->compressed = 1;
                                buffer = (char *) comp_buf;
                                returns.clen = bufsize = worklen + sizeof(struct tapebuf);
                        }
                        else {
                                /* write the data uncompressed */
                                comp_buf->length = writesize;
                                comp_buf->compressed = 0;
                                buffer = (char *) comp_buf;
                                returns.clen = bufsize = writesize + sizeof(struct tapebuf);
                                returns.unclen = returns.clen;
                                memcpy(comp_buf->buf, (char *)slp->tblock[0], writesize);
                        }
                }
                /* compress the remaining blocks if we're compressing */
                do_compress = compressed;
#endif /* HAVE_BLOCK_TRANSFORMATION */

                if (sigsetjmp(jmpbuf2, 1) == 0) {
                        ready2 = 1;
                        if (!caught2)
                                sigsuspend(&set);
                }
                ready2 = 0;
                caught2 = 0;

                indexer->updateQfa(&qfa_state);
                                                
                while (eot_count < 10 && size < bufsize) {
#ifdef RDUMP
                        if (host)
                                wrote = rmtwrite(buffer + size, bufsize - size);
                        else
#endif
                                wrote = write(tapefd, buffer + size, bufsize - size);
#ifdef WRITEDEBUG
                        printf("slave %d wrote %d\n", slave_number, wrote);
#endif
                        if (wrote < 0 && errno != ENOSPC)
                                break;
                        if (wrote == 0 || (wrote < 0 && errno == ENOSPC))
                                eot_count++;
                        else
                                size += wrote;
                }

#ifdef WRITEDEBUG
                if (size != bufsize)
                 printf("slave %d only wrote %d out of %d bytes and gave up.\n",
                     slave_number, size, bufsize);
#endif

                /*
                 * Handle ENOSPC as an EOT condition.
                 */
                if (wrote < 0 && errno == ENOSPC) {
                        wrote = 0;
                        eot_count++;
                }

                if (eot_count > 0)
                        returns.clen = returns.unclen = 0;

                /*
                 * pass errno back to master for special handling
                 */
                if (wrote < 0)
                        returns.unclen = -errno;

                /*
                 * pass size of data and size of write back to master
                 * (for EOT handling)
                 */
                (void) dump_atomic_write( cmd, (char *)&returns, sizeof returns);

                /*
                 * Signal the next slave to go.
                 */
                (void) kill(nextslave, SIGUSR2);

                indexer->updateQfaState(&qfa_state);
        }

#ifdef HAVE_BLOCK_TRANSFORMATION
        transformation->endDiskIOProcess(transformation);
#endif /* HAVE_BLOCK_TRANSFORMATION */

        if (nread != 0)
                quit("error reading command pipe: %s\n", strerror(errno));
}

/*
 * Since a read from a pipe may not return all we asked for,
 * or a write may not write all we ask if we get a signal,
 * loop until the count is satisfied (or error).
 */
static ssize_t
dump_atomic_read(int fd, char *buf, size_t count)
{
        int got, need = count;

        do {
                while ((got = read(fd, buf, need)) > 0 && (need -= got) > 0)
                        buf += got;
        } while (got == -1 && errno == EINTR);
        return (got < 0 ? got : (ssize_t)count - need);
}

/*
 * Since a read from a pipe may not return all we asked for,
 * or a write may not write all we ask if we get a signal,
 * loop until the count is satisfied (or error).
 */
static ssize_t
dump_atomic_write(int fd, const char *buf, size_t count)
{
        int got, need = count;

        do {
                while ((got = write(fd, buf, need)) > 0 && (need -= got) > 0)
                        buf += got;
        } while (got == -1 && errno == EINTR);
        return (got < 0 ? got : (ssize_t)count - need);
}


/*
int
SetLogicalPos(void)
{
        int     err = 0;
        struct mt_pos buf;

        buf.mt_op = MTSETDRVBUFFER;
        buf.mt_count = MT_ST_BOOLEANS | MT_ST_SCSI2LOGICAL;
        if (ioctl(tapefd, MTIOCTOP, &buf) == -1) {
                err = errno;
                msg("[%ld] error: %d (setting logical)\n", 
                        (unsigned long)getpid(), err);
        }
        return err;
}
*/