+/*
+ * Copyright (c) 1980 Regents of the University of California.
+ * All rights reserved. The Berkeley software License Agreement
+ * specifies the terms and conditions for redistribution.
+ */
+
+#ifndef lint
+static char sccsid[] = "@(#)dumptape.c 5.5 (Berkeley) 5/23/86";
+#endif not lint
+
+#include <sys/file.h>
+#include "dump.h"
+
+char (*tblock)[TP_BSIZE]; /* Pointer to malloc()ed buffer for tape */
+int writesize; /* Size of malloc()ed buffer for tape */
+int trecno = 0;
+extern int ntrec; /* blocking factor on tape */
+extern int cartridge;
+extern int read(), write();
+#ifdef RDUMP
+extern char *host;
+#endif RDUMP
+
+/*
+ * Concurrent dump mods (Caltech) - disk block reading and tape writing
+ * are exported to several slave processes. While one slave writes the
+ * tape, the others read disk blocks; they pass control of the tape in
+ * a ring via flock(). The parent process traverses the filesystem and
+ * sends spclrec()'s and lists of daddr's to the slaves via pipes.
+ */
+struct req { /* instruction packets sent to slaves */
+ daddr_t dblk;
+ int count;
+} *req;
+int reqsiz;
+
+#define SLAVES 3 /* 1 slave writing, 1 reading, 1 for slack */
+int slavefd[SLAVES]; /* pipes from master to each slave */
+int slavepid[SLAVES]; /* used by killall() */
+int rotor; /* next slave to be instructed */
+int master; /* pid of master, for sending error signals */
+int tenths; /* length of tape used per block written */
+
+alloctape()
+{
+ int pgoff = getpagesize() - 1;
+
+ writesize = ntrec * TP_BSIZE;
+ reqsiz = ntrec * 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.
+ */
+ tenths = writesize/density + (cartridge ? 16 : density == 625 ? 5 : 8);
+ /*
+ * Allocate tape buffer contiguous with the array of instruction
+ * packets, so flusht() can write them together with one write().
+ * Align tape buffer on page boundary to speed up tape write().
+ */
+ req = (struct req *)malloc(reqsiz + writesize + pgoff);
+ if (req == NULL)
+ return(0);
+ tblock = (char (*)[TP_BSIZE]) (((long)&req[ntrec] + pgoff) &~ pgoff);
+ req = (struct req *)tblock - ntrec;
+ return(1);
+}
+
+
+taprec(dp)
+ char *dp;
+{
+ req[trecno].dblk = (daddr_t)0;
+ req[trecno].count = 1;
+ *(union u_spcl *)(*tblock++) = *(union u_spcl *)dp; /* movc3 */
+ trecno++;
+ spcl.c_tapea++;
+ if(trecno >= ntrec)
+ flusht();
+}
+
+dmpblk(blkno, size)
+ daddr_t blkno;
+ int size;
+{
+ int avail, tpblks, dblkno;
+
+ dblkno = fsbtodb(sblock, blkno);
+ tpblks = size / TP_BSIZE;
+ while ((avail = MIN(tpblks, ntrec - trecno)) > 0) {
+ req[trecno].dblk = dblkno;
+ req[trecno].count = avail;
+ trecno += avail;
+ spcl.c_tapea += avail;
+ if (trecno >= ntrec)
+ flusht();
+ dblkno += avail * (TP_BSIZE / DEV_BSIZE);
+ tpblks -= avail;
+ }
+}
+
+int nogripe = 0;
+
+tperror() {
+ if (pipeout) {
+ msg("Tape write error on %s\n", tape);
+ msg("Cannot recover\n");
+ dumpabort();
+ /* NOTREACHED */
+ }
+ msg("Tape write error %d feet into tape %d\n", asize/120L, tapeno);
+ broadcast("TAPE ERROR!\n");
+ if (!query("Do you want to restart?"))
+ dumpabort();
+ msg("This tape will rewind. After it is rewound,\n");
+ msg("replace the faulty tape with a new one;\n");
+ msg("this dump volume will be rewritten.\n");
+ killall();
+ nogripe = 1;
+ close_rewind();
+ Exit(X_REWRITE);
+}
+
+sigpipe()
+{
+
+ msg("Broken pipe\n");
+ dumpabort();
+}
+
+#ifdef RDUMP
+/*
+ * compatibility routine
+ */
+tflush(i)
+ int i;
+{
+
+ for (i = 0; i < ntrec; i++)
+ spclrec();
+}
+#endif RDUMP
+
+flusht()
+{
+ int siz = (char *)tblock - (char *)req;
+
+ if (atomic(write, slavefd[rotor], req, siz) != siz) {
+ perror(" DUMP: error writing command pipe");
+ dumpabort();
+ }
+ if (++rotor >= SLAVES) rotor = 0;
+ tblock = (char (*)[TP_BSIZE]) &req[ntrec];
+ trecno = 0;
+ asize += tenths;
+ blockswritten += ntrec;
+ if (!pipeout && asize > tsize) {
+ close_rewind();
+ otape();
+ }
+ timeest();
+}
+
+rewind()
+{
+ int f;
+
+ if (pipeout)
+ return;
+ for (f = 0; f < SLAVES; f++)
+ close(slavefd[f]);
+ while (wait(NULL) >= 0) ; /* wait for any signals from slaves */
+ msg("Tape rewinding\n");
+#ifdef RDUMP
+ if (host) {
+ rmtclose();
+ while (rmtopen(tape, 0) < 0)
+ sleep(10);
+ rmtclose();
+ return;
+ }
+#endif RDUMP
+ close(to);
+ while ((f = open(tape, 0)) < 0)
+ sleep (10);
+ close(f);
+}
+
+close_rewind()
+{
+ rewind();
+ if (!nogripe) {
+ msg("Change Tapes: Mount tape #%d\n", tapeno+1);
+ broadcast("CHANGE TAPES!\7\7\n");
+ }
+ while (!query("Is the new tape mounted and ready to go?"))
+ if (query("Do you want to abort?")) {
+ dumpabort();
+ /*NOTREACHED*/
+ }
+}
+
+/*
+ * 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.
+ */
+
+otape()
+{
+ int parentpid;
+ int childpid;
+ int status;
+ int waitpid;
+ int (*interrupt)() = signal(SIGINT, SIG_IGN);
+
+ parentpid = getpid();
+
+ restore_check_point:
+ signal(SIGINT, interrupt);
+ /*
+ * All signals are inherited...
+ */
+ 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
+ while ((waitpid = wait(&status)) != childpid)
+ 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
+#ifdef RDUMP
+ while ((to = (host ? rmtopen(tape, 2) :
+ pipeout ? 1 : creat(tape, 0666))) < 0)
+#else RDUMP
+ while ((to = pipeout ? 1 : creat(tape, 0666)) < 0)
+#endif RDUMP
+ if (!query("Cannot open tape. Do you want to retry the open?"))
+ dumpabort();
+
+ enslave(); /* Share open tape file descriptor with slaves */
+
+ asize = 0;
+ tapeno++; /* current tape sequence */
+ newtape++; /* new tape signal */
+ spcl.c_volume++;
+ spcl.c_type = TS_TAPE;
+ spclrec();
+ if (tapeno > 1)
+ msg("Tape %d begins with blocks from ino %d\n",
+ tapeno, ino);
+ }
+}
+
+dumpabort()
+{
+ if (master != 0 && master != getpid())
+ kill(master, SIGTERM); /* Signals master to call dumpabort */
+ else {
+ killall();
+ msg("The ENTIRE dump is aborted.\n");
+ }
+ Exit(X_ABORT);
+}
+
+Exit(status)
+{
+#ifdef TDEBUG
+ msg("pid = %d exits with status %d\n", getpid(), status);
+#endif TDEBUG
+ exit(status);
+}
+
+/*
+ * could use pipe() for this if flock() worked on pipes
+ */
+lockfile(fd)
+ int fd[2];
+{
+ char tmpname[20];
+
+ strcpy(tmpname, "/tmp/dumplockXXXXXX");
+ mktemp(tmpname);
+ if ((fd[1] = creat(tmpname, 0400)) < 0) {
+ msg("Could not create lockfile ");
+ perror(tmpname);
+ dumpabort();
+ }
+ if ((fd[0] = open(tmpname, 0)) < 0) {
+ msg("Could not reopen lockfile ");
+ perror(tmpname);
+ dumpabort();
+ }
+ unlink(tmpname);
+}
+
+enslave()
+{
+ int first[2], prev[2], next[2], cmd[2]; /* file descriptors */
+ register 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 */
+ lockfile(first);
+ for (i = 0; i < SLAVES; i++) {
+ if (i == 0) {
+ prev[0] = first[1];
+ prev[1] = first[0];
+ } else {
+ prev[0] = next[0];
+ prev[1] = next[1];
+ flock(prev[1], LOCK_EX);
+ }
+ if (i < SLAVES - 1) {
+ lockfile(next);
+ } else {
+ next[0] = first[0];
+ next[1] = first[1]; /* Last slave loops back */
+ }
+ if (pipe(cmd) < 0 || (slavepid[i] = fork()) < 0) {
+ msg("too many slaves, %d (recompile smaller) ", i);
+ perror("");
+ dumpabort();
+ }
+ slavefd[i] = cmd[1];
+ if (slavepid[i] == 0) { /* Slave starts up here */
+ for (j = 0; j <= i; j++)
+ close(slavefd[j]);
+ signal(SIGINT, SIG_IGN); /* Master handles this */
+ doslave(cmd[0], prev, next);
+ Exit(X_FINOK);
+ }
+ close(cmd[0]);
+ if (i > 0) {
+ close(prev[0]);
+ close(prev[1]);
+ }
+ }
+ close(first[0]);
+ close(first[1]);
+ master = 0; rotor = 0;
+}
+
+killall()
+{
+ register int i;
+
+ for (i = 0; i < SLAVES; i++)
+ if (slavepid[i] > 0)
+ kill(slavepid[i], SIGKILL);
+}
+
+/*
+ * 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.
+ */
+doslave(cmd, prev, next)
+ register int cmd, prev[2], next[2];
+{
+ register int nread, toggle = 0;
+
+ close(fi);
+ if ((fi = open(disk, 0)) < 0) { /* Need our own seek pointer */
+ perror(" DUMP: slave couldn't reopen disk");
+ dumpabort();
+ }
+ /*
+ * Get list of blocks to dump, read the blocks into tape buffer
+ */
+ while ((nread = atomic(read, cmd, req, reqsiz)) == reqsiz) {
+ register struct req *p = req;
+ for (trecno = 0; trecno < ntrec; trecno += p->count, p += p->count) {
+ if (p->dblk) {
+ bread(p->dblk, tblock[trecno],
+ p->count * TP_BSIZE);
+ } else {
+ if (p->count != 1 || atomic(read, cmd,
+ tblock[trecno], TP_BSIZE) != TP_BSIZE) {
+ msg("Master/slave protocol botched.\n");
+ dumpabort();
+ }
+ }
+ }
+ flock(prev[toggle], LOCK_EX); /* Wait our turn */
+
+#ifdef RDUMP
+ if ((host ? rmtwrite(tblock[0], writesize)
+ : write(to, tblock[0], writesize)) != writesize) {
+#else RDUMP
+ if (write(to, tblock[0], writesize) != writesize) {
+#endif RDUMP
+ kill(master, SIGUSR1);
+ for (;;)
+ sigpause(0);
+ }
+ toggle ^= 1;
+ flock(next[toggle], LOCK_UN); /* Next slave's turn */
+ } /* Also jolts him awake */
+ if (nread != 0) {
+ perror(" DUMP: error reading command pipe");
+ dumpabort();
+ }
+}
+
+/*
+ * 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).
+ */
+atomic(func, fd, buf, count)
+ int (*func)(), fd, count;
+ char *buf;
+{
+ int got, need = count;
+
+ while ((got = (*func)(fd, buf, need)) > 0 && (need -= got) > 0)
+ buf += got;
+ return (got < 0 ? got : count - need);
+}
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