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 #include <sys/param.h>
33 #include <sys/socket.h>
34 #include <sys/wait.h>
35 #include <sys/stat.h>
36
37 #include <ufs/ufs/dinode.h>
38 #include <ufs/ffs/fs.h>
39
40 #include <protocols/dumprestore.h>
41
42 #include <assert.h>
43 #include <errno.h>
44 #include <fcntl.h>
45 #include <limits.h>
46 #include <setjmp.h>
47 #include <signal.h>
48 #include <stdio.h>
49 #include <stdlib.h>
50 #include <string.h>
51 #include <time.h>
52 #include <unistd.h>
53
54 #include "dump.h"
55
56 ino_t curino; /* current inumber; used globally */
57 int newtape; /* new tape flag */
58 union u_spcl u_spcl; /* mapping of variables in a control block */
59
60 static int tapefd; /* tape file descriptor */
61 static long asize; /* number of 0.1" units written on cur tape */
62 static int writesize; /* size of malloc()ed buffer for tape */
63 static int64_t lastspclrec = -1; /* tape block number of last written header */
64 static int trecno = 0; /* next record to write in current block */
65 static long blocksthisvol; /* number of blocks on current output file */
66 static char *nexttape;
67 static FILE *popenfp = NULL;
68
69 static int atomic_read(int, void *, int);
70 static int atomic_write(int, const void *, int);
71 static void worker(int, int);
72 static void create_workers(void);
73 static void flushtape(void);
74 static void killall(void);
75 static void rollforward(void);
76
77 /*
78 * Concurrent dump mods (Caltech) - disk block reading and tape writing
79 * are exported to several worker processes. While one worker writes the
80 * tape, the others read disk blocks; they pass control of the tape in
81 * a ring via signals. The parent process traverses the file system and
82 * sends writeheader()'s and lists of daddr's to the workers via pipes.
83 * The following structure defines the instruction packets sent to workers.
84 */
85 struct req {
86 ufs2_daddr_t dblk;
87 int count;
88 };
89 static int reqsiz;
90
91 #define WORKERS 3 /* 1 worker writing, 1 reading, 1 for slack */
92 static struct worker {
93 int64_t tapea; /* header number at start of this chunk */
94 int64_t firstrec; /* record number of this block */
95 int count; /* count to next header (used for TS_TAPE */
96 /* after EOT) */
97 int inode; /* inode that we are currently dealing with */
98 int fd; /* FD for this worker */
99 int pid; /* PID for this worker */
100 int sent; /* 1 == we've sent this worker requests */
101 char (*tblock)[TP_BSIZE]; /* buffer for data blocks */
102 struct req *req; /* buffer for requests */
103 } workers[WORKERS+1];
104 static struct worker *wp;
105
106 static char (*nextblock)[TP_BSIZE];
107
108 static int master; /* pid of master, for sending error signals */
109 static int tenths; /* length of tape used per block written */
110 static volatile sig_atomic_t caught; /* have we caught the signal to proceed? */
111 static volatile sig_atomic_t ready; /* reached the lock point without having */
112 /* received the SIGUSR2 signal from the prev worker? */
113 static jmp_buf jmpbuf; /* where to jump to if we are ready when the */
114 /* SIGUSR2 arrives from the previous worker */
115
116 int
alloctape(void)117 alloctape(void)
118 {
119 int pgoff = getpagesize() - 1;
120 char *buf;
121 int i;
122
123 writesize = ntrec * TP_BSIZE;
124 reqsiz = (ntrec + 1) * sizeof(struct req);
125 /*
126 * CDC 92181's and 92185's make 0.8" gaps in 1600-bpi start/stop mode
127 * (see DEC TU80 User's Guide). The shorter gaps of 6250-bpi require
128 * repositioning after stopping, i.e, streaming mode, where the gap is
129 * variable, 0.30" to 0.45". The gap is maximal when the tape stops.
130 */
131 if (blocksperfile == 0 && !unlimited)
132 tenths = writesize / density +
133 (cartridge ? 16 : density == 625 ? 5 : 8);
134 /*
135 * Allocate tape buffer contiguous with the array of instruction
136 * packets, so flushtape() can write them together with one write().
137 * Align tape buffer on page boundary to speed up tape write().
138 */
139 for (i = 0; i <= WORKERS; i++) {
140 buf = (char *)
141 malloc((unsigned)(reqsiz + writesize + pgoff + TP_BSIZE));
142 if (buf == NULL)
143 return(0);
144 workers[i].tblock = (char (*)[TP_BSIZE])
145 (((long)&buf[ntrec + 1] + pgoff) &~ pgoff);
146 workers[i].req = (struct req *)workers[i].tblock - ntrec - 1;
147 }
148 wp = &workers[0];
149 wp->count = 1;
150 wp->tapea = 0;
151 wp->firstrec = 0;
152 nextblock = wp->tblock;
153 return(1);
154 }
155
156 void
writerec(char * dp,int isspcl)157 writerec(char *dp, int isspcl)
158 {
159
160 wp->req[trecno].dblk = (ufs2_daddr_t)0;
161 wp->req[trecno].count = 1;
162 /* Can't do a structure assignment due to alignment problems */
163 bcopy(dp, *(nextblock)++, sizeof (union u_spcl));
164 if (isspcl)
165 lastspclrec = spcl.c_tapea;
166 trecno++;
167 spcl.c_tapea++;
168 if (trecno >= ntrec)
169 flushtape();
170 }
171
172 void
dumpblock(ufs2_daddr_t blkno,int size)173 dumpblock(ufs2_daddr_t blkno, int size)
174 {
175 int avail, tpblks;
176 ufs2_daddr_t dblkno;
177
178 dblkno = fsbtodb(sblock, blkno);
179 tpblks = size >> tp_bshift;
180 while ((avail = MIN(tpblks, ntrec - trecno)) > 0) {
181 wp->req[trecno].dblk = dblkno;
182 wp->req[trecno].count = avail;
183 trecno += avail;
184 spcl.c_tapea += avail;
185 if (trecno >= ntrec)
186 flushtape();
187 dblkno += avail << (tp_bshift - dev_bshift);
188 tpblks -= avail;
189 }
190 }
191
192 int nogripe = 0;
193
194 void
tperror(int signo __unused)195 tperror(int signo __unused)
196 {
197
198 if (pipeout) {
199 msg("write error on %s\n", tape);
200 quit("Cannot recover\n");
201 /* NOTREACHED */
202 }
203 msg("write error %ld blocks into volume %d\n", blocksthisvol, tapeno);
204 broadcast("DUMP WRITE ERROR!\n");
205 if (!query("Do you want to restart?"))
206 dumpabort(0);
207 msg("Closing this volume. Prepare to restart with new media;\n");
208 msg("this dump volume will be rewritten.\n");
209 killall();
210 nogripe = 1;
211 close_rewind();
212 Exit(X_REWRITE);
213 }
214
215 void
sigpipe(int signo __unused)216 sigpipe(int signo __unused)
217 {
218
219 quit("Broken pipe\n");
220 }
221
222 static void
flushtape(void)223 flushtape(void)
224 {
225 int i, blks, got;
226 int64_t lastfirstrec;
227
228 int siz = (char *)nextblock - (char *)wp->req;
229
230 wp->req[trecno].count = 0; /* Sentinel */
231
232 if (atomic_write(wp->fd, (const void *)wp->req, siz) != siz)
233 quit("error writing command pipe: %s\n", strerror(errno));
234 wp->sent = 1; /* we sent a request, read the response later */
235
236 lastfirstrec = wp->firstrec;
237
238 if (++wp >= &workers[WORKERS])
239 wp = &workers[0];
240
241 /* Read results back from next worker */
242 if (wp->sent) {
243 if (atomic_read(wp->fd, (void *)&got, sizeof got)
244 != sizeof got) {
245 perror(" DUMP: error reading command pipe in master");
246 dumpabort(0);
247 }
248 wp->sent = 0;
249
250 /* Check for end of tape */
251 if (got < writesize) {
252 msg("End of tape detected\n");
253
254 /*
255 * Drain the results, don't care what the values were.
256 * If we read them here then trewind won't...
257 */
258 for (i = 0; i < WORKERS; i++) {
259 if (workers[i].sent) {
260 if (atomic_read(workers[i].fd,
261 (void *)&got, sizeof got)
262 != sizeof got) {
263 perror(" DUMP: error reading command pipe in master");
264 dumpabort(0);
265 }
266 workers[i].sent = 0;
267 }
268 }
269
270 close_rewind();
271 rollforward();
272 return;
273 }
274 }
275
276 blks = 0;
277 if (spcl.c_type != TS_END && spcl.c_type != TS_CLRI &&
278 spcl.c_type != TS_BITS) {
279 assert(spcl.c_count <= TP_NINDIR);
280 for (i = 0; i < spcl.c_count; i++)
281 if (spcl.c_addr[i] != 0)
282 blks++;
283 }
284 wp->count = lastspclrec + blks + 1 - spcl.c_tapea;
285 wp->tapea = spcl.c_tapea;
286 wp->firstrec = lastfirstrec + ntrec;
287 wp->inode = curino;
288 nextblock = wp->tblock;
289 trecno = 0;
290 asize += tenths;
291 blockswritten += ntrec;
292 blocksthisvol += ntrec;
293 if (!pipeout && !unlimited && (blocksperfile ?
294 (blocksthisvol >= blocksperfile) : (asize > tsize))) {
295 close_rewind();
296 startnewtape(0);
297 }
298 timeest();
299 }
300
301 void
trewind(void)302 trewind(void)
303 {
304 struct stat sb;
305 int f;
306 int got;
307
308 for (f = 0; f < WORKERS; f++) {
309 /*
310 * Drain the results, but unlike EOT we DO (or should) care
311 * what the return values were, since if we detect EOT after
312 * we think we've written the last blocks to the tape anyway,
313 * we have to replay those blocks with rollforward.
314 *
315 * fixme: punt for now.
316 */
317 if (workers[f].sent) {
318 if (atomic_read(workers[f].fd, (void *)&got, sizeof got)
319 != sizeof got) {
320 perror(" DUMP: error reading command pipe in master");
321 dumpabort(0);
322 }
323 workers[f].sent = 0;
324 if (got != writesize) {
325 msg("EOT detected in last 2 tape records!\n");
326 msg("Use a longer tape, decrease the size estimate\n");
327 quit("or use no size estimate at all.\n");
328 }
329 }
330 (void) close(workers[f].fd);
331 }
332 while (wait((int *)NULL) >= 0) /* wait for any signals from workers */
333 /* void */;
334
335 if (pipeout)
336 return;
337
338 msg("Closing %s\n", tape);
339
340 if (popenout) {
341 tapefd = -1;
342 (void)pclose(popenfp);
343 popenfp = NULL;
344 return;
345 }
346 #ifdef RDUMP
347 if (host) {
348 rmtclose();
349 while (rmtopen(tape, 0) < 0)
350 sleep(10);
351 rmtclose();
352 return;
353 }
354 #endif
355 if (fstat(tapefd, &sb) == 0 && S_ISFIFO(sb.st_mode)) {
356 (void)close(tapefd);
357 return;
358 }
359 (void) close(tapefd);
360 while ((f = open(tape, 0)) < 0)
361 sleep (10);
362 (void) close(f);
363 }
364
365 void
close_rewind()366 close_rewind()
367 {
368 time_t tstart_changevol, tend_changevol;
369
370 trewind();
371 if (nexttape)
372 return;
373 (void)time((time_t *)&(tstart_changevol));
374 if (!nogripe) {
375 msg("Change Volumes: Mount volume #%d\n", tapeno+1);
376 broadcast("CHANGE DUMP VOLUMES!\a\a\n");
377 }
378 while (!query("Is the new volume mounted and ready to go?"))
379 if (query("Do you want to abort?")) {
380 dumpabort(0);
381 /*NOTREACHED*/
382 }
383 (void)time((time_t *)&(tend_changevol));
384 if ((tstart_changevol != (time_t)-1) && (tend_changevol != (time_t)-1))
385 tstart_writing += (tend_changevol - tstart_changevol);
386 }
387
388 void
rollforward(void)389 rollforward(void)
390 {
391 struct req *p, *q, *prev;
392 struct worker *twp;
393 int i, size, got;
394 int64_t savedtapea;
395 union u_spcl *ntb, *otb;
396 twp = &workers[WORKERS];
397 ntb = (union u_spcl *)twp->tblock[1];
398
399 /*
400 * Each of the N workers should have requests that need to
401 * be replayed on the next tape. Use the extra worker buffers
402 * (workers[WORKERS]) to construct request lists to be sent to
403 * each worker in turn.
404 */
405 for (i = 0; i < WORKERS; i++) {
406 q = &twp->req[1];
407 otb = (union u_spcl *)wp->tblock;
408
409 /*
410 * For each request in the current worker, copy it to twp.
411 */
412
413 prev = NULL;
414 for (p = wp->req; p->count > 0; p += p->count) {
415 *q = *p;
416 if (p->dblk == 0)
417 *ntb++ = *otb++; /* copy the datablock also */
418 prev = q;
419 q += q->count;
420 }
421 if (prev == NULL)
422 quit("rollforward: protocol botch");
423 if (prev->dblk != 0)
424 prev->count -= 1;
425 else
426 ntb--;
427 q -= 1;
428 q->count = 0;
429 q = &twp->req[0];
430 if (i == 0) {
431 q->dblk = 0;
432 q->count = 1;
433 trecno = 0;
434 nextblock = twp->tblock;
435 savedtapea = spcl.c_tapea;
436 spcl.c_tapea = wp->tapea;
437 startnewtape(0);
438 spcl.c_tapea = savedtapea;
439 lastspclrec = savedtapea - 1;
440 }
441 size = (char *)ntb - (char *)q;
442 if (atomic_write(wp->fd, (const void *)q, size) != size) {
443 perror(" DUMP: error writing command pipe");
444 dumpabort(0);
445 }
446 wp->sent = 1;
447 if (++wp >= &workers[WORKERS])
448 wp = &workers[0];
449
450 q->count = 1;
451
452 if (prev->dblk != 0) {
453 /*
454 * If the last one was a disk block, make the
455 * first of this one be the last bit of that disk
456 * block...
457 */
458 q->dblk = prev->dblk +
459 prev->count * (TP_BSIZE / DEV_BSIZE);
460 ntb = (union u_spcl *)twp->tblock;
461 } else {
462 /*
463 * It wasn't a disk block. Copy the data to its
464 * new location in the buffer.
465 */
466 q->dblk = 0;
467 *((union u_spcl *)twp->tblock) = *ntb;
468 ntb = (union u_spcl *)twp->tblock[1];
469 }
470 }
471 wp->req[0] = *q;
472 nextblock = wp->tblock;
473 if (q->dblk == 0)
474 nextblock++;
475 trecno = 1;
476
477 /*
478 * Clear the first workers' response. One hopes that it
479 * worked ok, otherwise the tape is much too short!
480 */
481 if (wp->sent) {
482 if (atomic_read(wp->fd, (void *)&got, sizeof got)
483 != sizeof got) {
484 perror(" DUMP: error reading command pipe in master");
485 dumpabort(0);
486 }
487 wp->sent = 0;
488
489 if (got != writesize) {
490 quit("EOT detected at start of the tape!\n");
491 }
492 }
493 }
494
495 /*
496 * We implement taking and restoring checkpoints on the tape level.
497 * When each tape is opened, a new process is created by forking; this
498 * saves all of the necessary context in the parent. The child
499 * continues the dump; the parent waits around, saving the context.
500 * If the child returns X_REWRITE, then it had problems writing that tape;
501 * this causes the parent to fork again, duplicating the context, and
502 * everything continues as if nothing had happened.
503 */
504 void
startnewtape(int top)505 startnewtape(int top)
506 {
507 int parentpid;
508 int childpid;
509 int status;
510 char *p;
511 sig_t interrupt_save;
512
513 interrupt_save = signal(SIGINT, SIG_IGN);
514 parentpid = getpid();
515
516 restore_check_point:
517 (void)signal(SIGINT, interrupt_save);
518 /*
519 * All signals are inherited...
520 */
521 setproctitle(NULL); /* Restore the proctitle. */
522 childpid = fork();
523 if (childpid < 0) {
524 msg("Context save fork fails in parent %d\n", parentpid);
525 Exit(X_ABORT);
526 }
527 if (childpid != 0) {
528 /*
529 * PARENT:
530 * save the context by waiting
531 * until the child doing all of the work returns.
532 * don't catch the interrupt
533 */
534 signal(SIGINT, SIG_IGN);
535 #ifdef TDEBUG
536 msg("Tape: %d; parent process: %d child process %d\n",
537 tapeno+1, parentpid, childpid);
538 #endif /* TDEBUG */
539 if (waitpid(childpid, &status, 0) == -1)
540 msg("Waiting for child %d: %s\n", childpid,
541 strerror(errno));
542 if (status & 0xFF) {
543 msg("Child %d returns LOB status %o\n",
544 childpid, status&0xFF);
545 }
546 status = (status >> 8) & 0xFF;
547 #ifdef TDEBUG
548 switch(status) {
549 case X_FINOK:
550 msg("Child %d finishes X_FINOK\n", childpid);
551 break;
552 case X_ABORT:
553 msg("Child %d finishes X_ABORT\n", childpid);
554 break;
555 case X_REWRITE:
556 msg("Child %d finishes X_REWRITE\n", childpid);
557 break;
558 default:
559 msg("Child %d finishes unknown %d\n",
560 childpid, status);
561 break;
562 }
563 #endif /* TDEBUG */
564 switch(status) {
565 case X_FINOK:
566 Exit(X_FINOK);
567 case X_ABORT:
568 Exit(X_ABORT);
569 case X_REWRITE:
570 goto restore_check_point;
571 default:
572 msg("Bad return code from dump: %d\n", status);
573 Exit(X_ABORT);
574 }
575 /*NOTREACHED*/
576 } else { /* we are the child; just continue */
577 #ifdef TDEBUG
578 sleep(4); /* allow time for parent's message to get out */
579 msg("Child on Tape %d has parent %d, my pid = %d\n",
580 tapeno+1, parentpid, getpid());
581 #endif /* TDEBUG */
582 /*
583 * If we have a name like "/dev/rmt0,/dev/rmt1",
584 * use the name before the comma first, and save
585 * the remaining names for subsequent volumes.
586 */
587 tapeno++; /* current tape sequence */
588 if (nexttape || strchr(tape, ',')) {
589 if (nexttape && *nexttape)
590 tape = nexttape;
591 if ((p = strchr(tape, ',')) != NULL) {
592 *p = '\0';
593 nexttape = p + 1;
594 } else
595 nexttape = NULL;
596 msg("Dumping volume %d on %s\n", tapeno, tape);
597 }
598 if (pipeout) {
599 tapefd = STDOUT_FILENO;
600 } else if (popenout) {
601 char volno[sizeof("2147483647")];
602
603 (void)sprintf(volno, "%d", spcl.c_volume + 1);
604 if (setenv("DUMP_VOLUME", volno, 1) == -1) {
605 msg("Cannot set $DUMP_VOLUME.\n");
606 dumpabort(0);
607 }
608 popenfp = popen(popenout, "w");
609 if (popenfp == NULL) {
610 msg("Cannot open output pipeline \"%s\".\n",
611 popenout);
612 dumpabort(0);
613 }
614 tapefd = fileno(popenfp);
615 } else {
616 #ifdef RDUMP
617 while ((tapefd = (host ? rmtopen(tape, 2) :
618 open(tape, O_WRONLY|O_CREAT, 0666))) < 0)
619 #else
620 while ((tapefd =
621 open(tape, O_WRONLY|O_CREAT, 0666)) < 0)
622 #endif
623 {
624 msg("Cannot open output \"%s\".\n", tape);
625 if (!query("Do you want to retry the open?"))
626 dumpabort(0);
627 }
628 }
629
630 create_workers(); /* Share open tape file descriptor with workers */
631 if (popenout)
632 close(tapefd); /* Give up our copy of it. */
633 signal(SIGINFO, infosch);
634
635 asize = 0;
636 blocksthisvol = 0;
637 if (top)
638 newtape++; /* new tape signal */
639 spcl.c_count = wp->count;
640 /*
641 * measure firstrec in TP_BSIZE units since restore doesn't
642 * know the correct ntrec value...
643 */
644 spcl.c_firstrec = wp->firstrec;
645 spcl.c_volume++;
646 spcl.c_type = TS_TAPE;
647 writeheader((ino_t)wp->inode);
648 if (tapeno > 1)
649 msg("Volume %d begins with blocks from inode %d\n",
650 tapeno, wp->inode);
651 }
652 }
653
654 void
dumpabort(int signo __unused)655 dumpabort(int signo __unused)
656 {
657
658 if (master != 0 && master != getpid())
659 /* Signals master to call dumpabort */
660 (void) kill(master, SIGTERM);
661 else {
662 killall();
663 msg("The ENTIRE dump is aborted.\n");
664 }
665 #ifdef RDUMP
666 rmtclose();
667 #endif
668 Exit(X_ABORT);
669 }
670
671 void
Exit(int status)672 Exit(int status)
673 {
674
675 #ifdef TDEBUG
676 msg("pid = %d exits with status %d\n", getpid(), status);
677 #endif /* TDEBUG */
678 exit(status);
679 }
680
681 /*
682 * proceed - handler for SIGUSR2, used to synchronize IO between the workers.
683 */
684 void
proceed(int signo __unused)685 proceed(int signo __unused)
686 {
687
688 if (ready)
689 longjmp(jmpbuf, 1);
690 caught++;
691 }
692
693 void
create_workers(void)694 create_workers(void)
695 {
696 int cmd[2];
697 int i, j;
698
699 master = getpid();
700
701 signal(SIGTERM, dumpabort); /* Worker sends SIGTERM on dumpabort() */
702 signal(SIGPIPE, sigpipe);
703 signal(SIGUSR1, tperror); /* Worker sends SIGUSR1 on tape errors */
704 signal(SIGUSR2, proceed); /* Worker sends SIGUSR2 to next worker */
705
706 for (i = 0; i < WORKERS; i++) {
707 if (i == wp - &workers[0]) {
708 caught = 1;
709 } else {
710 caught = 0;
711 }
712
713 if (socketpair(AF_UNIX, SOCK_STREAM, 0, cmd) < 0 ||
714 (workers[i].pid = fork()) < 0)
715 quit("too many workers, %d (recompile smaller): %s\n",
716 i, strerror(errno));
717
718 workers[i].fd = cmd[1];
719 workers[i].sent = 0;
720 if (workers[i].pid == 0) { /* Worker starts up here */
721 for (j = 0; j <= i; j++)
722 (void) close(workers[j].fd);
723 signal(SIGINT, SIG_IGN); /* Master handles this */
724 worker(cmd[0], i);
725 Exit(X_FINOK);
726 }
727 }
728
729 for (i = 0; i < WORKERS; i++)
730 (void) atomic_write(workers[i].fd,
731 (const void *) &workers[(i + 1) % WORKERS].pid,
732 sizeof workers[0].pid);
733
734 master = 0;
735 }
736
737 void
killall(void)738 killall(void)
739 {
740 int i;
741
742 for (i = 0; i < WORKERS; i++)
743 if (workers[i].pid > 0) {
744 (void) kill(workers[i].pid, SIGKILL);
745 workers[i].sent = 0;
746 }
747 }
748
749 /*
750 * Synchronization - each process has a lockfile, and shares file
751 * descriptors to the following process's lockfile. When our write
752 * completes, we release our lock on the following process's lock-
753 * file, allowing the following process to lock it and proceed. We
754 * get the lock back for the next cycle by swapping descriptors.
755 */
756 static void
worker(int cmd,int worker_number)757 worker(int cmd, int worker_number)
758 {
759 int nread;
760 int nextworker, size, wrote, eot_count;
761
762 /*
763 * Need our own seek pointer.
764 */
765 (void) close(diskfd);
766 if ((diskfd = open(disk, O_RDONLY)) < 0)
767 quit("worker couldn't reopen disk: %s\n", strerror(errno));
768
769 /*
770 * Need the pid of the next worker in the loop...
771 */
772 if ((nread = atomic_read(cmd, (void *)&nextworker, sizeof nextworker))
773 != sizeof nextworker) {
774 quit("master/worker protocol botched - didn't get pid of next worker.\n");
775 }
776
777 /*
778 * Get list of blocks to dump, read the blocks into tape buffer
779 */
780 while ((nread = atomic_read(cmd, (void *)wp->req, reqsiz)) == reqsiz) {
781 struct req *p = wp->req;
782
783 for (trecno = 0; trecno < ntrec;
784 trecno += p->count, p += p->count) {
785 if (p->dblk) {
786 blkread(p->dblk, wp->tblock[trecno],
787 p->count * TP_BSIZE);
788 } else {
789 if (p->count != 1 || atomic_read(cmd,
790 (void *)wp->tblock[trecno],
791 TP_BSIZE) != TP_BSIZE)
792 quit("master/worker protocol botched.\n");
793 }
794 }
795 if (setjmp(jmpbuf) == 0) {
796 ready = 1;
797 if (!caught)
798 (void) pause();
799 }
800 ready = 0;
801 caught = 0;
802
803 /* Try to write the data... */
804 eot_count = 0;
805 size = 0;
806
807 wrote = 0;
808 while (eot_count < 10 && size < writesize) {
809 #ifdef RDUMP
810 if (host)
811 wrote = rmtwrite(wp->tblock[0]+size,
812 writesize-size);
813 else
814 #endif
815 wrote = write(tapefd, wp->tblock[0]+size,
816 writesize-size);
817 #ifdef WRITEDEBUG
818 printf("worker %d wrote %d\n", worker_number, wrote);
819 #endif
820 if (wrote < 0)
821 break;
822 if (wrote == 0)
823 eot_count++;
824 size += wrote;
825 }
826
827 #ifdef WRITEDEBUG
828 if (size != writesize)
829 printf("worker %d only wrote %d out of %d bytes and gave up.\n",
830 worker_number, size, writesize);
831 #endif
832
833 /*
834 * Handle ENOSPC as an EOT condition.
835 */
836 if (wrote < 0 && errno == ENOSPC) {
837 wrote = 0;
838 eot_count++;
839 }
840
841 if (eot_count > 0)
842 size = 0;
843
844 if (wrote < 0) {
845 (void) kill(master, SIGUSR1);
846 for (;;)
847 (void) sigpause(0);
848 } else {
849 /*
850 * pass size of write back to master
851 * (for EOT handling)
852 */
853 (void)atomic_write(cmd, (const void *)&size,
854 sizeof size);
855 }
856
857 /*
858 * If partial write, don't want next worker to go.
859 * Also jolts him awake.
860 */
861 (void) kill(nextworker, SIGUSR2);
862 }
863 if (nread != 0)
864 quit("error reading command pipe: %s\n", strerror(errno));
865 }
866
867 /*
868 * Since a read from a pipe may not return all we asked for,
869 * loop until the count is satisfied (or error).
870 */
871 static int
atomic_read(int fd,void * buf,int count)872 atomic_read(int fd, void *buf, int count)
873 {
874 int got, need = count;
875
876 while ((got = read(fd, buf, need)) > 0 && (need -= got) > 0)
877 buf += got;
878 return (got < 0 ? got : count - need);
879 }
880
881 /*
882 * Since a write to a pipe may not write all we ask if we get a signal,
883 * loop until the count is satisfied (or error).
884 */
885 static int
atomic_write(int fd,const void * buf,int count)886 atomic_write(int fd, const void *buf, int count)
887 {
888 int got, need = count;
889
890 while ((got = write(fd, buf, need)) > 0 && (need -= got) > 0)
891 buf += got;
892 return (got < 0 ? got : count - need);
893 }
894