1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1980, 1991, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32 #ifndef lint
33 #if 0
34 static char sccsid[] = "@(#)tape.c 8.4 (Berkeley) 5/1/95";
35 #endif
36 static const char rcsid[] =
37 "$FreeBSD$";
38 #endif /* not lint */
39
40 #include <sys/param.h>
41 #include <sys/socket.h>
42 #include <sys/wait.h>
43 #include <sys/stat.h>
44
45 #include <ufs/ufs/dinode.h>
46 #include <ufs/ffs/fs.h>
47
48 #include <protocols/dumprestore.h>
49
50 #include <assert.h>
51 #include <errno.h>
52 #include <fcntl.h>
53 #include <limits.h>
54 #include <setjmp.h>
55 #include <signal.h>
56 #include <stdio.h>
57 #include <stdlib.h>
58 #include <string.h>
59 #include <time.h>
60 #include <unistd.h>
61
62 #include "dump.h"
63
64 ino_t curino; /* current inumber; used globally */
65 int newtape; /* new tape flag */
66 union u_spcl u_spcl; /* mapping of variables in a control block */
67
68 static int tapefd; /* tape file descriptor */
69 static long asize; /* number of 0.1" units written on cur tape */
70 static int writesize; /* size of malloc()ed buffer for tape */
71 static int64_t lastspclrec = -1; /* tape block number of last written header */
72 static int trecno = 0; /* next record to write in current block */
73 static long blocksthisvol; /* number of blocks on current output file */
74 static char *nexttape;
75 static FILE *popenfp = NULL;
76
77 static int atomic(ssize_t (*)(), int, char *, int);
78 static void worker(int, int);
79 static void create_workers(void);
80 static void flushtape(void);
81 static void killall(void);
82 static void rollforward(void);
83
84 /*
85 * Concurrent dump mods (Caltech) - disk block reading and tape writing
86 * are exported to several worker processes. While one worker writes the
87 * tape, the others read disk blocks; they pass control of the tape in
88 * a ring via signals. The parent process traverses the file system and
89 * sends writeheader()'s and lists of daddr's to the workers via pipes.
90 * The following structure defines the instruction packets sent to workers.
91 */
92 struct req {
93 ufs2_daddr_t dblk;
94 int count;
95 };
96 static int reqsiz;
97
98 #define WORKERS 3 /* 1 worker writing, 1 reading, 1 for slack */
99 static struct worker {
100 int64_t tapea; /* header number at start of this chunk */
101 int64_t firstrec; /* record number of this block */
102 int count; /* count to next header (used for TS_TAPE */
103 /* after EOT) */
104 int inode; /* inode that we are currently dealing with */
105 int fd; /* FD for this worker */
106 int pid; /* PID for this worker */
107 int sent; /* 1 == we've sent this worker requests */
108 char (*tblock)[TP_BSIZE]; /* buffer for data blocks */
109 struct req *req; /* buffer for requests */
110 } workers[WORKERS+1];
111 static struct worker *wp;
112
113 static char (*nextblock)[TP_BSIZE];
114
115 static int master; /* pid of master, for sending error signals */
116 static int tenths; /* length of tape used per block written */
117 static volatile sig_atomic_t caught; /* have we caught the signal to proceed? */
118 static volatile sig_atomic_t ready; /* reached the lock point without having */
119 /* received the SIGUSR2 signal from the prev worker? */
120 static jmp_buf jmpbuf; /* where to jump to if we are ready when the */
121 /* SIGUSR2 arrives from the previous worker */
122
123 int
alloctape(void)124 alloctape(void)
125 {
126 int pgoff = getpagesize() - 1;
127 char *buf;
128 int i;
129
130 writesize = ntrec * TP_BSIZE;
131 reqsiz = (ntrec + 1) * sizeof(struct req);
132 /*
133 * CDC 92181's and 92185's make 0.8" gaps in 1600-bpi start/stop mode
134 * (see DEC TU80 User's Guide). The shorter gaps of 6250-bpi require
135 * repositioning after stopping, i.e, streaming mode, where the gap is
136 * variable, 0.30" to 0.45". The gap is maximal when the tape stops.
137 */
138 if (blocksperfile == 0 && !unlimited)
139 tenths = writesize / density +
140 (cartridge ? 16 : density == 625 ? 5 : 8);
141 /*
142 * Allocate tape buffer contiguous with the array of instruction
143 * packets, so flushtape() can write them together with one write().
144 * Align tape buffer on page boundary to speed up tape write().
145 */
146 for (i = 0; i <= WORKERS; i++) {
147 buf = (char *)
148 malloc((unsigned)(reqsiz + writesize + pgoff + TP_BSIZE));
149 if (buf == NULL)
150 return(0);
151 workers[i].tblock = (char (*)[TP_BSIZE])
152 (((long)&buf[ntrec + 1] + pgoff) &~ pgoff);
153 workers[i].req = (struct req *)workers[i].tblock - ntrec - 1;
154 }
155 wp = &workers[0];
156 wp->count = 1;
157 wp->tapea = 0;
158 wp->firstrec = 0;
159 nextblock = wp->tblock;
160 return(1);
161 }
162
163 void
writerec(char * dp,int isspcl)164 writerec(char *dp, int isspcl)
165 {
166
167 wp->req[trecno].dblk = (ufs2_daddr_t)0;
168 wp->req[trecno].count = 1;
169 /* Can't do a structure assignment due to alignment problems */
170 bcopy(dp, *(nextblock)++, sizeof (union u_spcl));
171 if (isspcl)
172 lastspclrec = spcl.c_tapea;
173 trecno++;
174 spcl.c_tapea++;
175 if (trecno >= ntrec)
176 flushtape();
177 }
178
179 void
dumpblock(ufs2_daddr_t blkno,int size)180 dumpblock(ufs2_daddr_t blkno, int size)
181 {
182 int avail, tpblks;
183 ufs2_daddr_t dblkno;
184
185 dblkno = fsbtodb(sblock, blkno);
186 tpblks = size >> tp_bshift;
187 while ((avail = MIN(tpblks, ntrec - trecno)) > 0) {
188 wp->req[trecno].dblk = dblkno;
189 wp->req[trecno].count = avail;
190 trecno += avail;
191 spcl.c_tapea += avail;
192 if (trecno >= ntrec)
193 flushtape();
194 dblkno += avail << (tp_bshift - dev_bshift);
195 tpblks -= avail;
196 }
197 }
198
199 int nogripe = 0;
200
201 void
tperror(int signo __unused)202 tperror(int signo __unused)
203 {
204
205 if (pipeout) {
206 msg("write error on %s\n", tape);
207 quit("Cannot recover\n");
208 /* NOTREACHED */
209 }
210 msg("write error %ld blocks into volume %d\n", blocksthisvol, tapeno);
211 broadcast("DUMP WRITE ERROR!\n");
212 if (!query("Do you want to restart?"))
213 dumpabort(0);
214 msg("Closing this volume. Prepare to restart with new media;\n");
215 msg("this dump volume will be rewritten.\n");
216 killall();
217 nogripe = 1;
218 close_rewind();
219 Exit(X_REWRITE);
220 }
221
222 void
sigpipe(int signo __unused)223 sigpipe(int signo __unused)
224 {
225
226 quit("Broken pipe\n");
227 }
228
229 static void
flushtape(void)230 flushtape(void)
231 {
232 int i, blks, got;
233 int64_t lastfirstrec;
234
235 int siz = (char *)nextblock - (char *)wp->req;
236
237 wp->req[trecno].count = 0; /* Sentinel */
238
239 if (atomic(write, wp->fd, (char *)wp->req, siz) != siz)
240 quit("error writing command pipe: %s\n", strerror(errno));
241 wp->sent = 1; /* we sent a request, read the response later */
242
243 lastfirstrec = wp->firstrec;
244
245 if (++wp >= &workers[WORKERS])
246 wp = &workers[0];
247
248 /* Read results back from next worker */
249 if (wp->sent) {
250 if (atomic(read, wp->fd, (char *)&got, sizeof got)
251 != sizeof got) {
252 perror(" DUMP: error reading command pipe in master");
253 dumpabort(0);
254 }
255 wp->sent = 0;
256
257 /* Check for end of tape */
258 if (got < writesize) {
259 msg("End of tape detected\n");
260
261 /*
262 * Drain the results, don't care what the values were.
263 * If we read them here then trewind won't...
264 */
265 for (i = 0; i < WORKERS; i++) {
266 if (workers[i].sent) {
267 if (atomic(read, workers[i].fd,
268 (char *)&got, sizeof got)
269 != sizeof got) {
270 perror(" DUMP: error reading command pipe in master");
271 dumpabort(0);
272 }
273 workers[i].sent = 0;
274 }
275 }
276
277 close_rewind();
278 rollforward();
279 return;
280 }
281 }
282
283 blks = 0;
284 if (spcl.c_type != TS_END && spcl.c_type != TS_CLRI &&
285 spcl.c_type != TS_BITS) {
286 assert(spcl.c_count <= TP_NINDIR);
287 for (i = 0; i < spcl.c_count; i++)
288 if (spcl.c_addr[i] != 0)
289 blks++;
290 }
291 wp->count = lastspclrec + blks + 1 - spcl.c_tapea;
292 wp->tapea = spcl.c_tapea;
293 wp->firstrec = lastfirstrec + ntrec;
294 wp->inode = curino;
295 nextblock = wp->tblock;
296 trecno = 0;
297 asize += tenths;
298 blockswritten += ntrec;
299 blocksthisvol += ntrec;
300 if (!pipeout && !unlimited && (blocksperfile ?
301 (blocksthisvol >= blocksperfile) : (asize > tsize))) {
302 close_rewind();
303 startnewtape(0);
304 }
305 timeest();
306 }
307
308 void
trewind(void)309 trewind(void)
310 {
311 struct stat sb;
312 int f;
313 int got;
314
315 for (f = 0; f < WORKERS; f++) {
316 /*
317 * Drain the results, but unlike EOT we DO (or should) care
318 * what the return values were, since if we detect EOT after
319 * we think we've written the last blocks to the tape anyway,
320 * we have to replay those blocks with rollforward.
321 *
322 * fixme: punt for now.
323 */
324 if (workers[f].sent) {
325 if (atomic(read, workers[f].fd, (char *)&got, sizeof got)
326 != sizeof got) {
327 perror(" DUMP: error reading command pipe in master");
328 dumpabort(0);
329 }
330 workers[f].sent = 0;
331 if (got != writesize) {
332 msg("EOT detected in last 2 tape records!\n");
333 msg("Use a longer tape, decrease the size estimate\n");
334 quit("or use no size estimate at all.\n");
335 }
336 }
337 (void) close(workers[f].fd);
338 }
339 while (wait((int *)NULL) >= 0) /* wait for any signals from workers */
340 /* void */;
341
342 if (pipeout)
343 return;
344
345 msg("Closing %s\n", tape);
346
347 if (popenout) {
348 tapefd = -1;
349 (void)pclose(popenfp);
350 popenfp = NULL;
351 return;
352 }
353 #ifdef RDUMP
354 if (host) {
355 rmtclose();
356 while (rmtopen(tape, 0) < 0)
357 sleep(10);
358 rmtclose();
359 return;
360 }
361 #endif
362 if (fstat(tapefd, &sb) == 0 && S_ISFIFO(sb.st_mode)) {
363 (void)close(tapefd);
364 return;
365 }
366 (void) close(tapefd);
367 while ((f = open(tape, 0)) < 0)
368 sleep (10);
369 (void) close(f);
370 }
371
372 void
close_rewind()373 close_rewind()
374 {
375 time_t tstart_changevol, tend_changevol;
376
377 trewind();
378 if (nexttape)
379 return;
380 (void)time((time_t *)&(tstart_changevol));
381 if (!nogripe) {
382 msg("Change Volumes: Mount volume #%d\n", tapeno+1);
383 broadcast("CHANGE DUMP VOLUMES!\a\a\n");
384 }
385 while (!query("Is the new volume mounted and ready to go?"))
386 if (query("Do you want to abort?")) {
387 dumpabort(0);
388 /*NOTREACHED*/
389 }
390 (void)time((time_t *)&(tend_changevol));
391 if ((tstart_changevol != (time_t)-1) && (tend_changevol != (time_t)-1))
392 tstart_writing += (tend_changevol - tstart_changevol);
393 }
394
395 void
rollforward(void)396 rollforward(void)
397 {
398 struct req *p, *q, *prev;
399 struct worker *twp;
400 int i, size, got;
401 int64_t savedtapea;
402 union u_spcl *ntb, *otb;
403 twp = &workers[WORKERS];
404 ntb = (union u_spcl *)twp->tblock[1];
405
406 /*
407 * Each of the N workers should have requests that need to
408 * be replayed on the next tape. Use the extra worker buffers
409 * (workers[WORKERS]) to construct request lists to be sent to
410 * each worker in turn.
411 */
412 for (i = 0; i < WORKERS; i++) {
413 q = &twp->req[1];
414 otb = (union u_spcl *)wp->tblock;
415
416 /*
417 * For each request in the current worker, copy it to twp.
418 */
419
420 prev = NULL;
421 for (p = wp->req; p->count > 0; p += p->count) {
422 *q = *p;
423 if (p->dblk == 0)
424 *ntb++ = *otb++; /* copy the datablock also */
425 prev = q;
426 q += q->count;
427 }
428 if (prev == NULL)
429 quit("rollforward: protocol botch");
430 if (prev->dblk != 0)
431 prev->count -= 1;
432 else
433 ntb--;
434 q -= 1;
435 q->count = 0;
436 q = &twp->req[0];
437 if (i == 0) {
438 q->dblk = 0;
439 q->count = 1;
440 trecno = 0;
441 nextblock = twp->tblock;
442 savedtapea = spcl.c_tapea;
443 spcl.c_tapea = wp->tapea;
444 startnewtape(0);
445 spcl.c_tapea = savedtapea;
446 lastspclrec = savedtapea - 1;
447 }
448 size = (char *)ntb - (char *)q;
449 if (atomic(write, wp->fd, (char *)q, size) != size) {
450 perror(" DUMP: error writing command pipe");
451 dumpabort(0);
452 }
453 wp->sent = 1;
454 if (++wp >= &workers[WORKERS])
455 wp = &workers[0];
456
457 q->count = 1;
458
459 if (prev->dblk != 0) {
460 /*
461 * If the last one was a disk block, make the
462 * first of this one be the last bit of that disk
463 * block...
464 */
465 q->dblk = prev->dblk +
466 prev->count * (TP_BSIZE / DEV_BSIZE);
467 ntb = (union u_spcl *)twp->tblock;
468 } else {
469 /*
470 * It wasn't a disk block. Copy the data to its
471 * new location in the buffer.
472 */
473 q->dblk = 0;
474 *((union u_spcl *)twp->tblock) = *ntb;
475 ntb = (union u_spcl *)twp->tblock[1];
476 }
477 }
478 wp->req[0] = *q;
479 nextblock = wp->tblock;
480 if (q->dblk == 0)
481 nextblock++;
482 trecno = 1;
483
484 /*
485 * Clear the first workers' response. One hopes that it
486 * worked ok, otherwise the tape is much too short!
487 */
488 if (wp->sent) {
489 if (atomic(read, wp->fd, (char *)&got, sizeof got)
490 != sizeof got) {
491 perror(" DUMP: error reading command pipe in master");
492 dumpabort(0);
493 }
494 wp->sent = 0;
495
496 if (got != writesize) {
497 quit("EOT detected at start of the tape!\n");
498 }
499 }
500 }
501
502 /*
503 * We implement taking and restoring checkpoints on the tape level.
504 * When each tape is opened, a new process is created by forking; this
505 * saves all of the necessary context in the parent. The child
506 * continues the dump; the parent waits around, saving the context.
507 * If the child returns X_REWRITE, then it had problems writing that tape;
508 * this causes the parent to fork again, duplicating the context, and
509 * everything continues as if nothing had happened.
510 */
511 void
startnewtape(int top)512 startnewtape(int top)
513 {
514 int parentpid;
515 int childpid;
516 int status;
517 char *p;
518 sig_t interrupt_save;
519
520 interrupt_save = signal(SIGINT, SIG_IGN);
521 parentpid = getpid();
522
523 restore_check_point:
524 (void)signal(SIGINT, interrupt_save);
525 /*
526 * All signals are inherited...
527 */
528 setproctitle(NULL); /* Restore the proctitle. */
529 childpid = fork();
530 if (childpid < 0) {
531 msg("Context save fork fails in parent %d\n", parentpid);
532 Exit(X_ABORT);
533 }
534 if (childpid != 0) {
535 /*
536 * PARENT:
537 * save the context by waiting
538 * until the child doing all of the work returns.
539 * don't catch the interrupt
540 */
541 signal(SIGINT, SIG_IGN);
542 #ifdef TDEBUG
543 msg("Tape: %d; parent process: %d child process %d\n",
544 tapeno+1, parentpid, childpid);
545 #endif /* TDEBUG */
546 if (waitpid(childpid, &status, 0) == -1)
547 msg("Waiting for child %d: %s\n", childpid,
548 strerror(errno));
549 if (status & 0xFF) {
550 msg("Child %d returns LOB status %o\n",
551 childpid, status&0xFF);
552 }
553 status = (status >> 8) & 0xFF;
554 #ifdef TDEBUG
555 switch(status) {
556 case X_FINOK:
557 msg("Child %d finishes X_FINOK\n", childpid);
558 break;
559 case X_ABORT:
560 msg("Child %d finishes X_ABORT\n", childpid);
561 break;
562 case X_REWRITE:
563 msg("Child %d finishes X_REWRITE\n", childpid);
564 break;
565 default:
566 msg("Child %d finishes unknown %d\n",
567 childpid, status);
568 break;
569 }
570 #endif /* TDEBUG */
571 switch(status) {
572 case X_FINOK:
573 Exit(X_FINOK);
574 case X_ABORT:
575 Exit(X_ABORT);
576 case X_REWRITE:
577 goto restore_check_point;
578 default:
579 msg("Bad return code from dump: %d\n", status);
580 Exit(X_ABORT);
581 }
582 /*NOTREACHED*/
583 } else { /* we are the child; just continue */
584 #ifdef TDEBUG
585 sleep(4); /* allow time for parent's message to get out */
586 msg("Child on Tape %d has parent %d, my pid = %d\n",
587 tapeno+1, parentpid, getpid());
588 #endif /* TDEBUG */
589 /*
590 * If we have a name like "/dev/rmt0,/dev/rmt1",
591 * use the name before the comma first, and save
592 * the remaining names for subsequent volumes.
593 */
594 tapeno++; /* current tape sequence */
595 if (nexttape || strchr(tape, ',')) {
596 if (nexttape && *nexttape)
597 tape = nexttape;
598 if ((p = strchr(tape, ',')) != NULL) {
599 *p = '\0';
600 nexttape = p + 1;
601 } else
602 nexttape = NULL;
603 msg("Dumping volume %d on %s\n", tapeno, tape);
604 }
605 if (pipeout) {
606 tapefd = STDOUT_FILENO;
607 } else if (popenout) {
608 char volno[sizeof("2147483647")];
609
610 (void)sprintf(volno, "%d", spcl.c_volume + 1);
611 if (setenv("DUMP_VOLUME", volno, 1) == -1) {
612 msg("Cannot set $DUMP_VOLUME.\n");
613 dumpabort(0);
614 }
615 popenfp = popen(popenout, "w");
616 if (popenfp == NULL) {
617 msg("Cannot open output pipeline \"%s\".\n",
618 popenout);
619 dumpabort(0);
620 }
621 tapefd = fileno(popenfp);
622 } else {
623 #ifdef RDUMP
624 while ((tapefd = (host ? rmtopen(tape, 2) :
625 open(tape, O_WRONLY|O_CREAT, 0666))) < 0)
626 #else
627 while ((tapefd =
628 open(tape, O_WRONLY|O_CREAT, 0666)) < 0)
629 #endif
630 {
631 msg("Cannot open output \"%s\".\n", tape);
632 if (!query("Do you want to retry the open?"))
633 dumpabort(0);
634 }
635 }
636
637 create_workers(); /* Share open tape file descriptor with workers */
638 if (popenout)
639 close(tapefd); /* Give up our copy of it. */
640 signal(SIGINFO, infosch);
641
642 asize = 0;
643 blocksthisvol = 0;
644 if (top)
645 newtape++; /* new tape signal */
646 spcl.c_count = wp->count;
647 /*
648 * measure firstrec in TP_BSIZE units since restore doesn't
649 * know the correct ntrec value...
650 */
651 spcl.c_firstrec = wp->firstrec;
652 spcl.c_volume++;
653 spcl.c_type = TS_TAPE;
654 writeheader((ino_t)wp->inode);
655 if (tapeno > 1)
656 msg("Volume %d begins with blocks from inode %d\n",
657 tapeno, wp->inode);
658 }
659 }
660
661 void
dumpabort(int signo __unused)662 dumpabort(int signo __unused)
663 {
664
665 if (master != 0 && master != getpid())
666 /* Signals master to call dumpabort */
667 (void) kill(master, SIGTERM);
668 else {
669 killall();
670 msg("The ENTIRE dump is aborted.\n");
671 }
672 #ifdef RDUMP
673 rmtclose();
674 #endif
675 Exit(X_ABORT);
676 }
677
678 void
Exit(status)679 Exit(status)
680 int status;
681 {
682
683 #ifdef TDEBUG
684 msg("pid = %d exits with status %d\n", getpid(), status);
685 #endif /* TDEBUG */
686 exit(status);
687 }
688
689 /*
690 * proceed - handler for SIGUSR2, used to synchronize IO between the workers.
691 */
692 void
proceed(int signo __unused)693 proceed(int signo __unused)
694 {
695
696 if (ready)
697 longjmp(jmpbuf, 1);
698 caught++;
699 }
700
701 void
create_workers(void)702 create_workers(void)
703 {
704 int cmd[2];
705 int i, j;
706
707 master = getpid();
708
709 signal(SIGTERM, dumpabort); /* Worker sends SIGTERM on dumpabort() */
710 signal(SIGPIPE, sigpipe);
711 signal(SIGUSR1, tperror); /* Worker sends SIGUSR1 on tape errors */
712 signal(SIGUSR2, proceed); /* Worker sends SIGUSR2 to next worker */
713
714 for (i = 0; i < WORKERS; i++) {
715 if (i == wp - &workers[0]) {
716 caught = 1;
717 } else {
718 caught = 0;
719 }
720
721 if (socketpair(AF_UNIX, SOCK_STREAM, 0, cmd) < 0 ||
722 (workers[i].pid = fork()) < 0)
723 quit("too many workers, %d (recompile smaller): %s\n",
724 i, strerror(errno));
725
726 workers[i].fd = cmd[1];
727 workers[i].sent = 0;
728 if (workers[i].pid == 0) { /* Worker starts up here */
729 for (j = 0; j <= i; j++)
730 (void) close(workers[j].fd);
731 signal(SIGINT, SIG_IGN); /* Master handles this */
732 worker(cmd[0], i);
733 Exit(X_FINOK);
734 }
735 }
736
737 for (i = 0; i < WORKERS; i++)
738 (void) atomic(write, workers[i].fd,
739 (char *) &workers[(i + 1) % WORKERS].pid,
740 sizeof workers[0].pid);
741
742 master = 0;
743 }
744
745 void
killall(void)746 killall(void)
747 {
748 int i;
749
750 for (i = 0; i < WORKERS; i++)
751 if (workers[i].pid > 0) {
752 (void) kill(workers[i].pid, SIGKILL);
753 workers[i].sent = 0;
754 }
755 }
756
757 /*
758 * Synchronization - each process has a lockfile, and shares file
759 * descriptors to the following process's lockfile. When our write
760 * completes, we release our lock on the following process's lock-
761 * file, allowing the following process to lock it and proceed. We
762 * get the lock back for the next cycle by swapping descriptors.
763 */
764 static void
worker(int cmd,int worker_number)765 worker(int cmd, int worker_number)
766 {
767 int nread;
768 int nextworker, size, wrote, eot_count;
769
770 /*
771 * Need our own seek pointer.
772 */
773 (void) close(diskfd);
774 if ((diskfd = open(disk, O_RDONLY)) < 0)
775 quit("worker couldn't reopen disk: %s\n", strerror(errno));
776
777 /*
778 * Need the pid of the next worker in the loop...
779 */
780 if ((nread = atomic(read, cmd, (char *)&nextworker, sizeof nextworker))
781 != sizeof nextworker) {
782 quit("master/worker protocol botched - didn't get pid of next worker.\n");
783 }
784
785 /*
786 * Get list of blocks to dump, read the blocks into tape buffer
787 */
788 while ((nread = atomic(read, cmd, (char *)wp->req, reqsiz)) == reqsiz) {
789 struct req *p = wp->req;
790
791 for (trecno = 0; trecno < ntrec;
792 trecno += p->count, p += p->count) {
793 if (p->dblk) {
794 blkread(p->dblk, wp->tblock[trecno],
795 p->count * TP_BSIZE);
796 } else {
797 if (p->count != 1 || atomic(read, cmd,
798 (char *)wp->tblock[trecno],
799 TP_BSIZE) != TP_BSIZE)
800 quit("master/worker protocol botched.\n");
801 }
802 }
803 if (setjmp(jmpbuf) == 0) {
804 ready = 1;
805 if (!caught)
806 (void) pause();
807 }
808 ready = 0;
809 caught = 0;
810
811 /* Try to write the data... */
812 eot_count = 0;
813 size = 0;
814
815 wrote = 0;
816 while (eot_count < 10 && size < writesize) {
817 #ifdef RDUMP
818 if (host)
819 wrote = rmtwrite(wp->tblock[0]+size,
820 writesize-size);
821 else
822 #endif
823 wrote = write(tapefd, wp->tblock[0]+size,
824 writesize-size);
825 #ifdef WRITEDEBUG
826 printf("worker %d wrote %d\n", worker_number, wrote);
827 #endif
828 if (wrote < 0)
829 break;
830 if (wrote == 0)
831 eot_count++;
832 size += wrote;
833 }
834
835 #ifdef WRITEDEBUG
836 if (size != writesize)
837 printf("worker %d only wrote %d out of %d bytes and gave up.\n",
838 worker_number, size, writesize);
839 #endif
840
841 /*
842 * Handle ENOSPC as an EOT condition.
843 */
844 if (wrote < 0 && errno == ENOSPC) {
845 wrote = 0;
846 eot_count++;
847 }
848
849 if (eot_count > 0)
850 size = 0;
851
852 if (wrote < 0) {
853 (void) kill(master, SIGUSR1);
854 for (;;)
855 (void) sigpause(0);
856 } else {
857 /*
858 * pass size of write back to master
859 * (for EOT handling)
860 */
861 (void) atomic(write, cmd, (char *)&size, sizeof size);
862 }
863
864 /*
865 * If partial write, don't want next worker to go.
866 * Also jolts him awake.
867 */
868 (void) kill(nextworker, SIGUSR2);
869 }
870 if (nread != 0)
871 quit("error reading command pipe: %s\n", strerror(errno));
872 }
873
874 /*
875 * Since a read from a pipe may not return all we asked for,
876 * or a write may not write all we ask if we get a signal,
877 * loop until the count is satisfied (or error).
878 */
879 static int
atomic(ssize_t (* func)(),int fd,char * buf,int count)880 atomic(ssize_t (*func)(), int fd, char *buf, int count)
881 {
882 int got, need = count;
883
884 while ((got = (*func)(fd, buf, need)) > 0 && (need -= got) > 0)
885 buf += got;
886 return (got < 0 ? got : count - need);
887 }
888