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890005bf8a
with a signal handler. This fixes a race condition introduced by compiler reordering that caused dump to sometimes get stuck, especially while dumping large filesystems.
881 lines
22 KiB
C
881 lines
22 KiB
C
/*-
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* Copyright (c) 1980, 1991, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#ifndef lint
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#if 0
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static char sccsid[] = "@(#)tape.c 8.4 (Berkeley) 5/1/95";
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#endif
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static const char rcsid[] =
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"$FreeBSD$";
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#endif /* not lint */
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#include <sys/param.h>
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#include <sys/socket.h>
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#include <sys/time.h>
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#include <sys/wait.h>
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#include <sys/stat.h>
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#include <ufs/ufs/dinode.h>
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#include <ufs/ffs/fs.h>
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#include <protocols/dumprestore.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <limits.h>
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#include <setjmp.h>
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#include <signal.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include "dump.h"
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int writesize; /* size of malloc()ed buffer for tape */
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int64_t lastspclrec = -1; /* tape block number of last written header */
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int trecno = 0; /* next record to write in current block */
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extern long blocksperfile; /* number of blocks per output file */
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long blocksthisvol; /* number of blocks on current output file */
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extern int ntrec; /* blocking factor on tape */
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extern int cartridge;
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extern char *host;
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char *nexttape;
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FILE *popenfp = NULL;
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static int atomic(ssize_t (*)(), int, char *, int);
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static void doslave(int, int);
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static void enslave(void);
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static void flushtape(void);
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static void killall(void);
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static void rollforward(void);
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/*
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* Concurrent dump mods (Caltech) - disk block reading and tape writing
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* are exported to several slave processes. While one slave writes the
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* tape, the others read disk blocks; they pass control of the tape in
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* a ring via signals. The parent process traverses the file system and
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* sends writeheader()'s and lists of daddr's to the slaves via pipes.
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* The following structure defines the instruction packets sent to slaves.
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*/
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struct req {
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ufs2_daddr_t dblk;
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int count;
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};
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int reqsiz;
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#define SLAVES 3 /* 1 slave writing, 1 reading, 1 for slack */
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struct slave {
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int64_t tapea; /* header number at start of this chunk */
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int64_t firstrec; /* record number of this block */
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int count; /* count to next header (used for TS_TAPE */
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/* after EOT) */
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int inode; /* inode that we are currently dealing with */
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int fd; /* FD for this slave */
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int pid; /* PID for this slave */
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int sent; /* 1 == we've sent this slave requests */
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char (*tblock)[TP_BSIZE]; /* buffer for data blocks */
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struct req *req; /* buffer for requests */
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} slaves[SLAVES+1];
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struct slave *slp;
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char (*nextblock)[TP_BSIZE];
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int master; /* pid of master, for sending error signals */
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int tenths; /* length of tape used per block written */
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static volatile sig_atomic_t caught; /* have we caught the signal to proceed? */
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static volatile sig_atomic_t ready; /* reached the lock point without having */
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/* received the SIGUSR2 signal from the prev slave? */
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static jmp_buf jmpbuf; /* where to jump to if we are ready when the */
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/* SIGUSR2 arrives from the previous slave */
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int
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alloctape(void)
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{
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int pgoff = getpagesize() - 1;
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char *buf;
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int i;
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writesize = ntrec * TP_BSIZE;
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reqsiz = (ntrec + 1) * sizeof(struct req);
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/*
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* CDC 92181's and 92185's make 0.8" gaps in 1600-bpi start/stop mode
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* (see DEC TU80 User's Guide). The shorter gaps of 6250-bpi require
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* repositioning after stopping, i.e, streaming mode, where the gap is
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* variable, 0.30" to 0.45". The gap is maximal when the tape stops.
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*/
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if (blocksperfile == 0 && !unlimited)
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tenths = writesize / density +
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(cartridge ? 16 : density == 625 ? 5 : 8);
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/*
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* Allocate tape buffer contiguous with the array of instruction
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* packets, so flushtape() can write them together with one write().
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* Align tape buffer on page boundary to speed up tape write().
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*/
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for (i = 0; i <= SLAVES; i++) {
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buf = (char *)
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malloc((unsigned)(reqsiz + writesize + pgoff + TP_BSIZE));
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if (buf == NULL)
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return(0);
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slaves[i].tblock = (char (*)[TP_BSIZE])
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(((long)&buf[ntrec + 1] + pgoff) &~ pgoff);
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slaves[i].req = (struct req *)slaves[i].tblock - ntrec - 1;
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}
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slp = &slaves[0];
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slp->count = 1;
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slp->tapea = 0;
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slp->firstrec = 0;
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nextblock = slp->tblock;
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return(1);
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}
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void
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writerec(char *dp, int isspcl)
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{
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slp->req[trecno].dblk = (ufs2_daddr_t)0;
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slp->req[trecno].count = 1;
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/* Can't do a structure assignment due to alignment problems */
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bcopy(dp, *(nextblock)++, sizeof (union u_spcl));
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if (isspcl)
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lastspclrec = spcl.c_tapea;
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trecno++;
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spcl.c_tapea++;
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if (trecno >= ntrec)
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flushtape();
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}
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void
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dumpblock(ufs2_daddr_t blkno, int size)
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{
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int avail, tpblks;
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ufs2_daddr_t dblkno;
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dblkno = fsbtodb(sblock, blkno);
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tpblks = size >> tp_bshift;
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while ((avail = MIN(tpblks, ntrec - trecno)) > 0) {
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slp->req[trecno].dblk = dblkno;
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slp->req[trecno].count = avail;
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trecno += avail;
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spcl.c_tapea += avail;
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if (trecno >= ntrec)
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flushtape();
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dblkno += avail << (tp_bshift - dev_bshift);
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tpblks -= avail;
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}
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}
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int nogripe = 0;
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void
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tperror(int signo __unused)
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{
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if (pipeout) {
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msg("write error on %s\n", tape);
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quit("Cannot recover\n");
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/* NOTREACHED */
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}
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msg("write error %ld blocks into volume %d\n", blocksthisvol, tapeno);
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broadcast("DUMP WRITE ERROR!\n");
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if (!query("Do you want to restart?"))
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dumpabort(0);
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msg("Closing this volume. Prepare to restart with new media;\n");
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msg("this dump volume will be rewritten.\n");
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killall();
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nogripe = 1;
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close_rewind();
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Exit(X_REWRITE);
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}
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void
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sigpipe(int signo __unused)
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{
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quit("Broken pipe\n");
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}
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static void
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flushtape(void)
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{
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int i, blks, got;
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int64_t lastfirstrec;
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int siz = (char *)nextblock - (char *)slp->req;
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slp->req[trecno].count = 0; /* Sentinel */
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if (atomic(write, slp->fd, (char *)slp->req, siz) != siz)
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quit("error writing command pipe: %s\n", strerror(errno));
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slp->sent = 1; /* we sent a request, read the response later */
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lastfirstrec = slp->firstrec;
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if (++slp >= &slaves[SLAVES])
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slp = &slaves[0];
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/* Read results back from next slave */
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if (slp->sent) {
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if (atomic(read, slp->fd, (char *)&got, sizeof got)
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!= sizeof got) {
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perror(" DUMP: error reading command pipe in master");
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dumpabort(0);
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}
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slp->sent = 0;
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/* Check for end of tape */
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if (got < writesize) {
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msg("End of tape detected\n");
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/*
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* Drain the results, don't care what the values were.
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* If we read them here then trewind won't...
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*/
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for (i = 0; i < SLAVES; i++) {
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if (slaves[i].sent) {
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if (atomic(read, slaves[i].fd,
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(char *)&got, sizeof got)
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!= sizeof got) {
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perror(" DUMP: error reading command pipe in master");
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dumpabort(0);
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}
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slaves[i].sent = 0;
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}
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}
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close_rewind();
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rollforward();
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return;
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}
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}
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blks = 0;
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if (spcl.c_type != TS_END) {
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for (i = 0; i < spcl.c_count; i++)
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if (spcl.c_addr[i] != 0)
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blks++;
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}
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slp->count = lastspclrec + blks + 1 - spcl.c_tapea;
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slp->tapea = spcl.c_tapea;
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slp->firstrec = lastfirstrec + ntrec;
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slp->inode = curino;
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nextblock = slp->tblock;
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trecno = 0;
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asize += tenths;
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blockswritten += ntrec;
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blocksthisvol += ntrec;
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if (!pipeout && !unlimited && (blocksperfile ?
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(blocksthisvol >= blocksperfile) : (asize > tsize))) {
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close_rewind();
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startnewtape(0);
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}
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timeest();
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}
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void
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trewind(void)
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{
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struct stat sb;
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int f;
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int got;
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for (f = 0; f < SLAVES; f++) {
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/*
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* Drain the results, but unlike EOT we DO (or should) care
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* what the return values were, since if we detect EOT after
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* we think we've written the last blocks to the tape anyway,
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* we have to replay those blocks with rollforward.
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*
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* fixme: punt for now.
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*/
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if (slaves[f].sent) {
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if (atomic(read, slaves[f].fd, (char *)&got, sizeof got)
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!= sizeof got) {
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perror(" DUMP: error reading command pipe in master");
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dumpabort(0);
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}
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slaves[f].sent = 0;
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if (got != writesize) {
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msg("EOT detected in last 2 tape records!\n");
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msg("Use a longer tape, decrease the size estimate\n");
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quit("or use no size estimate at all.\n");
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}
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}
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(void) close(slaves[f].fd);
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}
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while (wait((int *)NULL) >= 0) /* wait for any signals from slaves */
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/* void */;
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if (pipeout)
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return;
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msg("Closing %s\n", tape);
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if (popenout) {
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tapefd = -1;
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(void)pclose(popenfp);
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popenfp = NULL;
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return;
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}
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#ifdef RDUMP
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if (host) {
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rmtclose();
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while (rmtopen(tape, 0) < 0)
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sleep(10);
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rmtclose();
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return;
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}
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#endif
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if (fstat(tapefd, &sb) == 0 && S_ISFIFO(sb.st_mode)) {
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(void)close(tapefd);
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return;
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}
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(void) close(tapefd);
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while ((f = open(tape, 0)) < 0)
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sleep (10);
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(void) close(f);
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}
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void
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close_rewind()
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{
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time_t tstart_changevol, tend_changevol;
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trewind();
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if (nexttape)
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return;
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(void)time((time_t *)&(tstart_changevol));
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if (!nogripe) {
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msg("Change Volumes: Mount volume #%d\n", tapeno+1);
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broadcast("CHANGE DUMP VOLUMES!\a\a\n");
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}
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while (!query("Is the new volume mounted and ready to go?"))
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if (query("Do you want to abort?")) {
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dumpabort(0);
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/*NOTREACHED*/
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}
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(void)time((time_t *)&(tend_changevol));
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if ((tstart_changevol != (time_t)-1) && (tend_changevol != (time_t)-1))
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tstart_writing += (tend_changevol - tstart_changevol);
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}
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void
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rollforward(void)
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{
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struct req *p, *q, *prev;
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struct slave *tslp;
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int i, size, got;
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int64_t savedtapea;
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union u_spcl *ntb, *otb;
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tslp = &slaves[SLAVES];
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ntb = (union u_spcl *)tslp->tblock[1];
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/*
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* Each of the N slaves should have requests that need to
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* be replayed on the next tape. Use the extra slave buffers
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* (slaves[SLAVES]) to construct request lists to be sent to
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* each slave in turn.
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*/
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for (i = 0; i < SLAVES; i++) {
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q = &tslp->req[1];
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otb = (union u_spcl *)slp->tblock;
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/*
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* For each request in the current slave, copy it to tslp.
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*/
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prev = NULL;
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for (p = slp->req; p->count > 0; p += p->count) {
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*q = *p;
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if (p->dblk == 0)
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*ntb++ = *otb++; /* copy the datablock also */
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prev = q;
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q += q->count;
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}
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if (prev == NULL)
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quit("rollforward: protocol botch");
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if (prev->dblk != 0)
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prev->count -= 1;
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else
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ntb--;
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q -= 1;
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q->count = 0;
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q = &tslp->req[0];
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if (i == 0) {
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q->dblk = 0;
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q->count = 1;
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trecno = 0;
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nextblock = tslp->tblock;
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savedtapea = spcl.c_tapea;
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spcl.c_tapea = slp->tapea;
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startnewtape(0);
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spcl.c_tapea = savedtapea;
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lastspclrec = savedtapea - 1;
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}
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size = (char *)ntb - (char *)q;
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if (atomic(write, slp->fd, (char *)q, size) != size) {
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perror(" DUMP: error writing command pipe");
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dumpabort(0);
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}
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slp->sent = 1;
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if (++slp >= &slaves[SLAVES])
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slp = &slaves[0];
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q->count = 1;
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if (prev->dblk != 0) {
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/*
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* If the last one was a disk block, make the
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* first of this one be the last bit of that disk
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* block...
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*/
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q->dblk = prev->dblk +
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prev->count * (TP_BSIZE / DEV_BSIZE);
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ntb = (union u_spcl *)tslp->tblock;
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} else {
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/*
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* It wasn't a disk block. Copy the data to its
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* new location in the buffer.
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*/
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q->dblk = 0;
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*((union u_spcl *)tslp->tblock) = *ntb;
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ntb = (union u_spcl *)tslp->tblock[1];
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}
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}
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slp->req[0] = *q;
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nextblock = slp->tblock;
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if (q->dblk == 0)
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nextblock++;
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trecno = 1;
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/*
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* Clear the first slaves' response. One hopes that it
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* worked ok, otherwise the tape is much too short!
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*/
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if (slp->sent) {
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if (atomic(read, slp->fd, (char *)&got, sizeof got)
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!= sizeof got) {
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perror(" DUMP: error reading command pipe in master");
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dumpabort(0);
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}
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slp->sent = 0;
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if (got != writesize) {
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quit("EOT detected at start of the tape!\n");
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}
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}
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}
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/*
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* We implement taking and restoring checkpoints on the tape level.
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* When each tape is opened, a new process is created by forking; this
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* saves all of the necessary context in the parent. The child
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* continues the dump; the parent waits around, saving the context.
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* If the child returns X_REWRITE, then it had problems writing that tape;
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* this causes the parent to fork again, duplicating the context, and
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* everything continues as if nothing had happened.
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*/
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void
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startnewtape(int top)
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{
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int parentpid;
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int childpid;
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int status;
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char *p;
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sig_t interrupt_save;
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|
|
interrupt_save = signal(SIGINT, SIG_IGN);
|
|
parentpid = getpid();
|
|
|
|
restore_check_point:
|
|
(void)signal(SIGINT, interrupt_save);
|
|
/*
|
|
* All signals are inherited...
|
|
*/
|
|
setproctitle(NULL); /* Restore the proctitle. */
|
|
childpid = fork();
|
|
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
|
|
*/
|
|
signal(SIGINT, SIG_IGN);
|
|
#ifdef TDEBUG
|
|
msg("Tape: %d; parent process: %d child process %d\n",
|
|
tapeno+1, parentpid, childpid);
|
|
#endif /* TDEBUG */
|
|
if (waitpid(childpid, &status, 0) == -1)
|
|
msg("Waiting for child %d: %s\n", childpid,
|
|
strerror(errno));
|
|
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 (nexttape || strchr(tape, ',')) {
|
|
if (nexttape && *nexttape)
|
|
tape = nexttape;
|
|
if ((p = strchr(tape, ',')) != NULL) {
|
|
*p = '\0';
|
|
nexttape = p + 1;
|
|
} else
|
|
nexttape = NULL;
|
|
msg("Dumping volume %d on %s\n", tapeno, tape);
|
|
}
|
|
if (pipeout) {
|
|
tapefd = STDOUT_FILENO;
|
|
} else if (popenout) {
|
|
char volno[sizeof("2147483647")];
|
|
|
|
(void)sprintf(volno, "%d", spcl.c_volume + 1);
|
|
if (setenv("DUMP_VOLUME", volno, 1) == -1) {
|
|
msg("Cannot set $DUMP_VOLUME.\n");
|
|
dumpabort(0);
|
|
}
|
|
popenfp = popen(popenout, "w");
|
|
if (popenfp == NULL) {
|
|
msg("Cannot open output pipeline \"%s\".\n",
|
|
popenout);
|
|
dumpabort(0);
|
|
}
|
|
tapefd = fileno(popenfp);
|
|
} else {
|
|
#ifdef RDUMP
|
|
while ((tapefd = (host ? rmtopen(tape, 2) :
|
|
open(tape, O_WRONLY|O_CREAT, 0666))) < 0)
|
|
#else
|
|
while ((tapefd =
|
|
open(tape, O_WRONLY|O_CREAT, 0666)) < 0)
|
|
#endif
|
|
{
|
|
msg("Cannot open output \"%s\".\n", tape);
|
|
if (!query("Do you want to retry the open?"))
|
|
dumpabort(0);
|
|
}
|
|
}
|
|
|
|
enslave(); /* Share open tape file descriptor with slaves */
|
|
if (popenout)
|
|
close(tapefd); /* Give up our copy of it. */
|
|
signal(SIGINFO, infosch);
|
|
|
|
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;
|
|
writeheader((ino_t)slp->inode);
|
|
if (tapeno > 1)
|
|
msg("Volume %d begins with blocks from inode %d\n",
|
|
tapeno, slp->inode);
|
|
}
|
|
}
|
|
|
|
void
|
|
dumpabort(int signo __unused)
|
|
{
|
|
|
|
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(status)
|
|
int status;
|
|
{
|
|
|
|
#ifdef TDEBUG
|
|
msg("pid = %d exits with status %d\n", getpid(), status);
|
|
#endif /* TDEBUG */
|
|
exit(status);
|
|
}
|
|
|
|
/*
|
|
* proceed - handler for SIGUSR2, used to synchronize IO between the slaves.
|
|
*/
|
|
void
|
|
proceed(int signo __unused)
|
|
{
|
|
|
|
if (ready)
|
|
longjmp(jmpbuf, 1);
|
|
caught++;
|
|
}
|
|
|
|
void
|
|
enslave(void)
|
|
{
|
|
int cmd[2];
|
|
int i, j;
|
|
|
|
master = getpid();
|
|
|
|
signal(SIGTERM, dumpabort); /* Slave sends SIGTERM on dumpabort() */
|
|
signal(SIGPIPE, sigpipe);
|
|
signal(SIGUSR1, tperror); /* Slave sends SIGUSR1 on tape errors */
|
|
signal(SIGUSR2, proceed); /* Slave sends SIGUSR2 to next slave */
|
|
|
|
for (i = 0; i < SLAVES; i++) {
|
|
if (i == slp - &slaves[0]) {
|
|
caught = 1;
|
|
} else {
|
|
caught = 0;
|
|
}
|
|
|
|
if (socketpair(AF_UNIX, SOCK_STREAM, 0, cmd) < 0 ||
|
|
(slaves[i].pid = fork()) < 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 */
|
|
for (j = 0; j <= i; j++)
|
|
(void) close(slaves[j].fd);
|
|
signal(SIGINT, SIG_IGN); /* Master handles this */
|
|
doslave(cmd[0], i);
|
|
Exit(X_FINOK);
|
|
}
|
|
}
|
|
|
|
for (i = 0; i < SLAVES; i++)
|
|
(void) 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 has a lockfile, and shares file
|
|
* descriptors to the following process's lockfile. When our write
|
|
* completes, we release our lock on the following process's lock-
|
|
* file, allowing the following process to lock it and proceed. We
|
|
* get the lock back for the next cycle by swapping descriptors.
|
|
*/
|
|
static void
|
|
doslave(int cmd, int slave_number)
|
|
{
|
|
int nread;
|
|
int nextslave, size, wrote, eot_count;
|
|
|
|
/*
|
|
* 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));
|
|
|
|
/*
|
|
* Need the pid of the next slave in the loop...
|
|
*/
|
|
if ((nread = atomic(read, cmd, (char *)&nextslave, sizeof nextslave))
|
|
!= sizeof nextslave) {
|
|
quit("master/slave protocol botched - didn't get pid of next slave.\n");
|
|
}
|
|
|
|
/*
|
|
* Get list of blocks to dump, read the blocks into tape buffer
|
|
*/
|
|
while ((nread = atomic(read, cmd, (char *)slp->req, reqsiz)) == reqsiz) {
|
|
struct req *p = slp->req;
|
|
|
|
for (trecno = 0; trecno < ntrec;
|
|
trecno += p->count, p += p->count) {
|
|
if (p->dblk) {
|
|
bread(p->dblk, slp->tblock[trecno],
|
|
p->count * TP_BSIZE);
|
|
} else {
|
|
if (p->count != 1 || atomic(read, cmd,
|
|
(char *)slp->tblock[trecno],
|
|
TP_BSIZE) != TP_BSIZE)
|
|
quit("master/slave protocol botched.\n");
|
|
}
|
|
}
|
|
if (setjmp(jmpbuf) == 0) {
|
|
ready = 1;
|
|
if (!caught)
|
|
(void) pause();
|
|
}
|
|
ready = 0;
|
|
caught = 0;
|
|
|
|
/* Try to write the data... */
|
|
eot_count = 0;
|
|
size = 0;
|
|
|
|
wrote = 0;
|
|
while (eot_count < 10 && size < writesize) {
|
|
#ifdef RDUMP
|
|
if (host)
|
|
wrote = rmtwrite(slp->tblock[0]+size,
|
|
writesize-size);
|
|
else
|
|
#endif
|
|
wrote = write(tapefd, slp->tblock[0]+size,
|
|
writesize-size);
|
|
#ifdef WRITEDEBUG
|
|
printf("slave %d wrote %d\n", slave_number, wrote);
|
|
#endif
|
|
if (wrote < 0)
|
|
break;
|
|
if (wrote == 0)
|
|
eot_count++;
|
|
size += wrote;
|
|
}
|
|
|
|
#ifdef WRITEDEBUG
|
|
if (size != writesize)
|
|
printf("slave %d only wrote %d out of %d bytes and gave up.\n",
|
|
slave_number, size, writesize);
|
|
#endif
|
|
|
|
/*
|
|
* Handle ENOSPC as an EOT condition.
|
|
*/
|
|
if (wrote < 0 && errno == ENOSPC) {
|
|
wrote = 0;
|
|
eot_count++;
|
|
}
|
|
|
|
if (eot_count > 0)
|
|
size = 0;
|
|
|
|
if (wrote < 0) {
|
|
(void) kill(master, SIGUSR1);
|
|
for (;;)
|
|
(void) sigpause(0);
|
|
} else {
|
|
/*
|
|
* pass size of write back to master
|
|
* (for EOT handling)
|
|
*/
|
|
(void) atomic(write, cmd, (char *)&size, sizeof size);
|
|
}
|
|
|
|
/*
|
|
* If partial write, don't want next slave to go.
|
|
* Also jolts him awake.
|
|
*/
|
|
(void) kill(nextslave, SIGUSR2);
|
|
}
|
|
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 int
|
|
atomic(ssize_t (*func)(), int fd, char *buf, int count)
|
|
{
|
|
int got, need = count;
|
|
|
|
while ((got = (*func)(fd, buf, need)) > 0 && (need -= got) > 0)
|
|
buf += got;
|
|
return (got < 0 ? got : count - need);
|
|
}
|