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