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 doslave(int, int); 79 static void enslave(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 slave processes. While one slave 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 slaves via pipes. 90 * The following structure defines the instruction packets sent to slaves. 91 */ 92 struct req { 93 ufs2_daddr_t dblk; 94 int count; 95 }; 96 static int reqsiz; 97 98 #define SLAVES 3 /* 1 slave writing, 1 reading, 1 for slack */ 99 static struct slave { 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 slave */ 106 int pid; /* PID for this slave */ 107 int sent; /* 1 == we've sent this slave requests */ 108 char (*tblock)[TP_BSIZE]; /* buffer for data blocks */ 109 struct req *req; /* buffer for requests */ 110 } slaves[SLAVES+1]; 111 static struct slave *slp; 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 slave? */ 120 static jmp_buf jmpbuf; /* where to jump to if we are ready when the */ 121 /* SIGUSR2 arrives from the previous slave */ 122 123 int 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 <= SLAVES; i++) { 147 buf = (char *) 148 malloc((unsigned)(reqsiz + writesize + pgoff + TP_BSIZE)); 149 if (buf == NULL) 150 return(0); 151 slaves[i].tblock = (char (*)[TP_BSIZE]) 152 (((long)&buf[ntrec + 1] + pgoff) &~ pgoff); 153 slaves[i].req = (struct req *)slaves[i].tblock - ntrec - 1; 154 } 155 slp = &slaves[0]; 156 slp->count = 1; 157 slp->tapea = 0; 158 slp->firstrec = 0; 159 nextblock = slp->tblock; 160 return(1); 161 } 162 163 void 164 writerec(char *dp, int isspcl) 165 { 166 167 slp->req[trecno].dblk = (ufs2_daddr_t)0; 168 slp->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 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 slp->req[trecno].dblk = dblkno; 189 slp->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 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 223 sigpipe(int signo __unused) 224 { 225 226 quit("Broken pipe\n"); 227 } 228 229 static void 230 flushtape(void) 231 { 232 int i, blks, got; 233 int64_t lastfirstrec; 234 235 int siz = (char *)nextblock - (char *)slp->req; 236 237 slp->req[trecno].count = 0; /* Sentinel */ 238 239 if (atomic(write, slp->fd, (char *)slp->req, siz) != siz) 240 quit("error writing command pipe: %s\n", strerror(errno)); 241 slp->sent = 1; /* we sent a request, read the response later */ 242 243 lastfirstrec = slp->firstrec; 244 245 if (++slp >= &slaves[SLAVES]) 246 slp = &slaves[0]; 247 248 /* Read results back from next slave */ 249 if (slp->sent) { 250 if (atomic(read, slp->fd, (char *)&got, sizeof got) 251 != sizeof got) { 252 perror(" DUMP: error reading command pipe in master"); 253 dumpabort(0); 254 } 255 slp->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 < SLAVES; i++) { 266 if (slaves[i].sent) { 267 if (atomic(read, slaves[i].fd, 268 (char *)&got, sizeof got) 269 != sizeof got) { 270 perror(" DUMP: error reading command pipe in master"); 271 dumpabort(0); 272 } 273 slaves[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 slp->count = lastspclrec + blks + 1 - spcl.c_tapea; 292 slp->tapea = spcl.c_tapea; 293 slp->firstrec = lastfirstrec + ntrec; 294 slp->inode = curino; 295 nextblock = slp->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 309 trewind(void) 310 { 311 struct stat sb; 312 int f; 313 int got; 314 315 for (f = 0; f < SLAVES; 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 (slaves[f].sent) { 325 if (atomic(read, slaves[f].fd, (char *)&got, sizeof got) 326 != sizeof got) { 327 perror(" DUMP: error reading command pipe in master"); 328 dumpabort(0); 329 } 330 slaves[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(slaves[f].fd); 338 } 339 while (wait((int *)NULL) >= 0) /* wait for any signals from slaves */ 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 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 396 rollforward(void) 397 { 398 struct req *p, *q, *prev; 399 struct slave *tslp; 400 int i, size, got; 401 int64_t savedtapea; 402 union u_spcl *ntb, *otb; 403 tslp = &slaves[SLAVES]; 404 ntb = (union u_spcl *)tslp->tblock[1]; 405 406 /* 407 * Each of the N slaves should have requests that need to 408 * be replayed on the next tape. Use the extra slave buffers 409 * (slaves[SLAVES]) to construct request lists to be sent to 410 * each slave in turn. 411 */ 412 for (i = 0; i < SLAVES; i++) { 413 q = &tslp->req[1]; 414 otb = (union u_spcl *)slp->tblock; 415 416 /* 417 * For each request in the current slave, copy it to tslp. 418 */ 419 420 prev = NULL; 421 for (p = slp->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 = &tslp->req[0]; 437 if (i == 0) { 438 q->dblk = 0; 439 q->count = 1; 440 trecno = 0; 441 nextblock = tslp->tblock; 442 savedtapea = spcl.c_tapea; 443 spcl.c_tapea = slp->tapea; 444 startnewtape(0); 445 spcl.c_tapea = savedtapea; 446 lastspclrec = savedtapea - 1; 447 } 448 size = (char *)ntb - (char *)q; 449 if (atomic(write, slp->fd, (char *)q, size) != size) { 450 perror(" DUMP: error writing command pipe"); 451 dumpabort(0); 452 } 453 slp->sent = 1; 454 if (++slp >= &slaves[SLAVES]) 455 slp = &slaves[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 *)tslp->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 *)tslp->tblock) = *ntb; 475 ntb = (union u_spcl *)tslp->tblock[1]; 476 } 477 } 478 slp->req[0] = *q; 479 nextblock = slp->tblock; 480 if (q->dblk == 0) 481 nextblock++; 482 trecno = 1; 483 484 /* 485 * Clear the first slaves' response. One hopes that it 486 * worked ok, otherwise the tape is much too short! 487 */ 488 if (slp->sent) { 489 if (atomic(read, slp->fd, (char *)&got, sizeof got) 490 != sizeof got) { 491 perror(" DUMP: error reading command pipe in master"); 492 dumpabort(0); 493 } 494 slp->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 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 enslave(); /* Share open tape file descriptor with slaves */ 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 = slp->count; 647 /* 648 * measure firstrec in TP_BSIZE units since restore doesn't 649 * know the correct ntrec value... 650 */ 651 spcl.c_firstrec = slp->firstrec; 652 spcl.c_volume++; 653 spcl.c_type = TS_TAPE; 654 writeheader((ino_t)slp->inode); 655 if (tapeno > 1) 656 msg("Volume %d begins with blocks from inode %d\n", 657 tapeno, slp->inode); 658 } 659 } 660 661 void 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 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 slaves. 691 */ 692 void 693 proceed(int signo __unused) 694 { 695 696 if (ready) 697 longjmp(jmpbuf, 1); 698 caught++; 699 } 700 701 void 702 enslave(void) 703 { 704 int cmd[2]; 705 int i, j; 706 707 master = getpid(); 708 709 signal(SIGTERM, dumpabort); /* Slave sends SIGTERM on dumpabort() */ 710 signal(SIGPIPE, sigpipe); 711 signal(SIGUSR1, tperror); /* Slave sends SIGUSR1 on tape errors */ 712 signal(SIGUSR2, proceed); /* Slave sends SIGUSR2 to next slave */ 713 714 for (i = 0; i < SLAVES; i++) { 715 if (i == slp - &slaves[0]) { 716 caught = 1; 717 } else { 718 caught = 0; 719 } 720 721 if (socketpair(AF_UNIX, SOCK_STREAM, 0, cmd) < 0 || 722 (slaves[i].pid = fork()) < 0) 723 quit("too many slaves, %d (recompile smaller): %s\n", 724 i, strerror(errno)); 725 726 slaves[i].fd = cmd[1]; 727 slaves[i].sent = 0; 728 if (slaves[i].pid == 0) { /* Slave starts up here */ 729 for (j = 0; j <= i; j++) 730 (void) close(slaves[j].fd); 731 signal(SIGINT, SIG_IGN); /* Master handles this */ 732 doslave(cmd[0], i); 733 Exit(X_FINOK); 734 } 735 } 736 737 for (i = 0; i < SLAVES; i++) 738 (void) atomic(write, slaves[i].fd, 739 (char *) &slaves[(i + 1) % SLAVES].pid, 740 sizeof slaves[0].pid); 741 742 master = 0; 743 } 744 745 void 746 killall(void) 747 { 748 int i; 749 750 for (i = 0; i < SLAVES; i++) 751 if (slaves[i].pid > 0) { 752 (void) kill(slaves[i].pid, SIGKILL); 753 slaves[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 765 doslave(int cmd, int slave_number) 766 { 767 int nread; 768 int nextslave, 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("slave couldn't reopen disk: %s\n", strerror(errno)); 776 777 /* 778 * Need the pid of the next slave in the loop... 779 */ 780 if ((nread = atomic(read, cmd, (char *)&nextslave, sizeof nextslave)) 781 != sizeof nextslave) { 782 quit("master/slave protocol botched - didn't get pid of next slave.\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 *)slp->req, reqsiz)) == reqsiz) { 789 struct req *p = slp->req; 790 791 for (trecno = 0; trecno < ntrec; 792 trecno += p->count, p += p->count) { 793 if (p->dblk) { 794 blkread(p->dblk, slp->tblock[trecno], 795 p->count * TP_BSIZE); 796 } else { 797 if (p->count != 1 || atomic(read, cmd, 798 (char *)slp->tblock[trecno], 799 TP_BSIZE) != TP_BSIZE) 800 quit("master/slave 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(slp->tblock[0]+size, 820 writesize-size); 821 else 822 #endif 823 wrote = write(tapefd, slp->tblock[0]+size, 824 writesize-size); 825 #ifdef WRITEDEBUG 826 printf("slave %d wrote %d\n", slave_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("slave %d only wrote %d out of %d bytes and gave up.\n", 838 slave_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 slave to go. 866 * Also jolts him awake. 867 */ 868 (void) kill(nextslave, 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 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