1 /*- 2 * Copyright (c) 1980, 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * @(#)tape.c 8.4 (Berkeley) 5/1/95 34 * $FreeBSD: src/sbin/dump/tape.c,v 1.12.2.3 2002/02/23 22:32:51 iedowse Exp $ 35 * $DragonFly: src/sbin/dump/tape.c,v 1.6 2004/02/04 17:39:59 joerg Exp $ 36 */ 37 38 #include <sys/param.h> 39 #include <sys/socket.h> 40 #include <sys/time.h> 41 #include <sys/wait.h> 42 #include <sys/stat.h> 43 #ifdef sunos 44 #include <sys/vnode.h> 45 46 #include <ufs/fs.h> 47 #include <ufs/inode.h> 48 #else 49 #include <vfs/ufs/dinode.h> 50 #include <vfs/ufs/fs.h> 51 #endif 52 53 #include <protocols/dumprestore.h> 54 55 #include <errno.h> 56 #include <fcntl.h> 57 #include <setjmp.h> 58 #include <signal.h> 59 #include <stdio.h> 60 #ifdef __STDC__ 61 #include <stdlib.h> 62 #include <string.h> 63 #include <unistd.h> 64 #else 65 int write(), read(); 66 #endif 67 68 #include "dump.h" 69 70 int writesize; /* size of malloc()ed buffer for tape */ 71 long lastspclrec = -1; /* tape block number of last written header */ 72 int trecno = 0; /* next record to write in current block */ 73 extern long blocksperfile; /* number of blocks per output file */ 74 long blocksthisvol; /* number of blocks on current output file */ 75 extern int ntrec; /* blocking factor on tape */ 76 extern int cartridge; 77 extern char *host; 78 char *nexttape; 79 80 static int atomic(ssize_t (*)(), int, char *, int); 81 static void doslave(int, int); 82 static void enslave(void); 83 static void flushtape(void); 84 static void killall(void); 85 static void rollforward(void); 86 87 /* 88 * Concurrent dump mods (Caltech) - disk block reading and tape writing 89 * are exported to several slave processes. While one slave writes the 90 * tape, the others read disk blocks; they pass control of the tape in 91 * a ring via signals. The parent process traverses the filesystem and 92 * sends writeheader()'s and lists of daddr's to the slaves via pipes. 93 * The following structure defines the instruction packets sent to slaves. 94 */ 95 struct req { 96 daddr_t dblk; 97 int count; 98 }; 99 int reqsiz; 100 101 #define SLAVES 3 /* 1 slave writing, 1 reading, 1 for slack */ 102 struct slave { 103 int tapea; /* header number at start of this chunk */ 104 int count; /* count to next header (used for TS_TAPE */ 105 /* after EOT) */ 106 int inode; /* inode that we are currently dealing with */ 107 int fd; /* FD for this slave */ 108 int pid; /* PID for this slave */ 109 int sent; /* 1 == we've sent this slave requests */ 110 int firstrec; /* record number of this block */ 111 char (*tblock)[TP_BSIZE]; /* buffer for data blocks */ 112 struct req *req; /* buffer for requests */ 113 } slaves[SLAVES+1]; 114 struct slave *slp; 115 116 char (*nextblock)[TP_BSIZE]; 117 118 int master; /* pid of master, for sending error signals */ 119 int tenths; /* length of tape used per block written */ 120 static int caught; /* have we caught the signal to proceed? */ 121 static int ready; /* have we reached the lock point without having */ 122 /* received the SIGUSR2 signal from the prev slave? */ 123 static jmp_buf jmpbuf; /* where to jump to if we are ready when the */ 124 /* SIGUSR2 arrives from the previous slave */ 125 126 int 127 alloctape(void) 128 { 129 int pgoff = getpagesize() - 1; 130 char *buf; 131 int i; 132 133 writesize = ntrec * TP_BSIZE; 134 reqsiz = (ntrec + 1) * sizeof(struct req); 135 /* 136 * CDC 92181's and 92185's make 0.8" gaps in 1600-bpi start/stop mode 137 * (see DEC TU80 User's Guide). The shorter gaps of 6250-bpi require 138 * repositioning after stopping, i.e, streaming mode, where the gap is 139 * variable, 0.30" to 0.45". The gap is maximal when the tape stops. 140 */ 141 if (blocksperfile == 0 && !unlimited) 142 tenths = writesize / density + 143 (cartridge ? 16 : density == 625 ? 5 : 8); 144 /* 145 * Allocate tape buffer contiguous with the array of instruction 146 * packets, so flushtape() can write them together with one write(). 147 * Align tape buffer on page boundary to speed up tape write(). 148 */ 149 for (i = 0; i <= SLAVES; i++) { 150 buf = (char *) 151 malloc((unsigned)(reqsiz + writesize + pgoff + TP_BSIZE)); 152 if (buf == NULL) 153 return(0); 154 slaves[i].tblock = (char (*)[TP_BSIZE]) 155 (((long)&buf[ntrec + 1] + pgoff) &~ pgoff); 156 slaves[i].req = (struct req *)slaves[i].tblock - ntrec - 1; 157 } 158 slp = &slaves[0]; 159 slp->count = 1; 160 slp->tapea = 0; 161 slp->firstrec = 0; 162 nextblock = slp->tblock; 163 return(1); 164 } 165 166 void 167 writerec(char *dp, int isspcl) 168 { 169 170 slp->req[trecno].dblk = (daddr_t)0; 171 slp->req[trecno].count = 1; 172 #ifndef __alpha__ 173 *(union u_spcl *)(*(nextblock)++) = *(union u_spcl *)dp; 174 #else 175 bcopy(dp, *(nextblock)++, sizeof (union u_spcl)); 176 #endif 177 if (isspcl) 178 lastspclrec = spcl.c_tapea; 179 trecno++; 180 spcl.c_tapea++; 181 if (trecno >= ntrec) 182 flushtape(); 183 } 184 185 void 186 dumpblock(daddr_t blkno, int size) 187 { 188 int avail, tpblks, dblkno; 189 190 dblkno = fsbtodb(sblock, blkno); 191 tpblks = size >> tp_bshift; 192 while ((avail = MIN(tpblks, ntrec - trecno)) > 0) { 193 slp->req[trecno].dblk = dblkno; 194 slp->req[trecno].count = avail; 195 trecno += avail; 196 spcl.c_tapea += avail; 197 if (trecno >= ntrec) 198 flushtape(); 199 dblkno += avail << (tp_bshift - dev_bshift); 200 tpblks -= avail; 201 } 202 } 203 204 int nogripe = 0; 205 206 void 207 tperror(int signo) 208 { 209 210 if (pipeout) { 211 msg("write error on %s\n", tape); 212 quit("Cannot recover\n"); 213 /* NOTREACHED */ 214 } 215 msg("write error %ld blocks into volume %d\n", blocksthisvol, tapeno); 216 broadcast("DUMP WRITE ERROR!\n"); 217 if (!query("Do you want to restart?")) 218 dumpabort(0); 219 msg("Closing this volume. Prepare to restart with new media;\n"); 220 msg("this dump volume will be rewritten.\n"); 221 killall(); 222 nogripe = 1; 223 close_rewind(); 224 Exit(X_REWRITE); 225 } 226 227 void 228 sigpipe(int signo) 229 { 230 231 quit("Broken pipe\n"); 232 } 233 234 static void 235 flushtape(void) 236 { 237 int i, blks, got; 238 long lastfirstrec; 239 240 int siz = (char *)nextblock - (char *)slp->req; 241 242 slp->req[trecno].count = 0; /* Sentinel */ 243 244 if (atomic(write, slp->fd, (char *)slp->req, siz) != siz) 245 quit("error writing command pipe: %s\n", strerror(errno)); 246 slp->sent = 1; /* we sent a request, read the response later */ 247 248 lastfirstrec = slp->firstrec; 249 250 if (++slp >= &slaves[SLAVES]) 251 slp = &slaves[0]; 252 253 /* Read results back from next slave */ 254 if (slp->sent) { 255 if (atomic(read, slp->fd, (char *)&got, sizeof got) 256 != sizeof got) { 257 perror(" DUMP: error reading command pipe in master"); 258 dumpabort(0); 259 } 260 slp->sent = 0; 261 262 /* Check for end of tape */ 263 if (got < writesize) { 264 msg("End of tape detected\n"); 265 266 /* 267 * Drain the results, don't care what the values were. 268 * If we read them here then trewind won't... 269 */ 270 for (i = 0; i < SLAVES; i++) { 271 if (slaves[i].sent) { 272 if (atomic(read, slaves[i].fd, 273 (char *)&got, sizeof got) 274 != sizeof got) { 275 perror(" DUMP: error reading command pipe in master"); 276 dumpabort(0); 277 } 278 slaves[i].sent = 0; 279 } 280 } 281 282 close_rewind(); 283 rollforward(); 284 return; 285 } 286 } 287 288 blks = 0; 289 if (spcl.c_type != TS_END) { 290 for (i = 0; i < spcl.c_count; i++) 291 if (spcl.c_addr[i] != 0) 292 blks++; 293 } 294 slp->count = lastspclrec + blks + 1 - spcl.c_tapea; 295 slp->tapea = spcl.c_tapea; 296 slp->firstrec = lastfirstrec + ntrec; 297 slp->inode = curino; 298 nextblock = slp->tblock; 299 trecno = 0; 300 asize += tenths; 301 blockswritten += ntrec; 302 blocksthisvol += ntrec; 303 if (!pipeout && !unlimited && (blocksperfile ? 304 (blocksthisvol >= blocksperfile) : (asize > tsize))) { 305 close_rewind(); 306 startnewtape(0); 307 } 308 timeest(); 309 } 310 311 void 312 trewind(void) 313 { 314 struct stat sb; 315 int f; 316 int got; 317 318 for (f = 0; f < SLAVES; f++) { 319 /* 320 * Drain the results, but unlike EOT we DO (or should) care 321 * what the return values were, since if we detect EOT after 322 * we think we've written the last blocks to the tape anyway, 323 * we have to replay those blocks with rollforward. 324 * 325 * fixme: punt for now. 326 */ 327 if (slaves[f].sent) { 328 if (atomic(read, slaves[f].fd, (char *)&got, sizeof got) 329 != sizeof got) { 330 perror(" DUMP: error reading command pipe in master"); 331 dumpabort(0); 332 } 333 slaves[f].sent = 0; 334 if (got != writesize) { 335 msg("EOT detected in last 2 tape records!\n"); 336 msg("Use a longer tape, decrease the size estimate\n"); 337 quit("or use no size estimate at all.\n"); 338 } 339 } 340 (void) close(slaves[f].fd); 341 } 342 while (wait((int *)NULL) >= 0) /* wait for any signals from slaves */ 343 /* void */; 344 345 if (pipeout) 346 return; 347 348 msg("Closing %s\n", tape); 349 350 #ifdef RDUMP 351 if (host) { 352 rmtclose(); 353 while (rmtopen(tape, 0) < 0) 354 sleep(10); 355 rmtclose(); 356 return; 357 } 358 #endif 359 if (fstat(tapefd, &sb) == 0 && S_ISFIFO(sb.st_mode)) { 360 (void)close(tapefd); 361 return; 362 } 363 (void) close(tapefd); 364 while ((f = open(tape, 0)) < 0) 365 sleep (10); 366 (void) close(f); 367 } 368 369 void 370 close_rewind(void) 371 { 372 time_t tstart_changevol, tend_changevol; 373 374 trewind(); 375 if (nexttape) 376 return; 377 (void)time((time_t *)&(tstart_changevol)); 378 if (!nogripe) { 379 msg("Change Volumes: Mount volume #%d\n", tapeno+1); 380 broadcast("CHANGE DUMP VOLUMES!\a\a\n"); 381 } 382 while (!query("Is the new volume mounted and ready to go?")) 383 if (query("Do you want to abort?")) { 384 dumpabort(0); 385 /*NOTREACHED*/ 386 } 387 (void)time((time_t *)&(tend_changevol)); 388 if ((tstart_changevol != (time_t)-1) && (tend_changevol != (time_t)-1)) 389 tstart_writing += (tend_changevol - tstart_changevol); 390 } 391 392 void 393 rollforward(void) 394 { 395 register struct req *p, *q, *prev; 396 register struct slave *tslp; 397 int i, size, savedtapea, got; 398 union u_spcl *ntb, *otb; 399 tslp = &slaves[SLAVES]; 400 ntb = (union u_spcl *)tslp->tblock[1]; 401 402 /* 403 * Each of the N slaves should have requests that need to 404 * be replayed on the next tape. Use the extra slave buffers 405 * (slaves[SLAVES]) to construct request lists to be sent to 406 * each slave in turn. 407 */ 408 for (i = 0; i < SLAVES; i++) { 409 q = &tslp->req[1]; 410 otb = (union u_spcl *)slp->tblock; 411 412 /* 413 * For each request in the current slave, copy it to tslp. 414 */ 415 416 prev = NULL; 417 for (p = slp->req; p->count > 0; p += p->count) { 418 *q = *p; 419 if (p->dblk == 0) 420 *ntb++ = *otb++; /* copy the datablock also */ 421 prev = q; 422 q += q->count; 423 } 424 if (prev == NULL) 425 quit("rollforward: protocol botch"); 426 if (prev->dblk != 0) 427 prev->count -= 1; 428 else 429 ntb--; 430 q -= 1; 431 q->count = 0; 432 q = &tslp->req[0]; 433 if (i == 0) { 434 q->dblk = 0; 435 q->count = 1; 436 trecno = 0; 437 nextblock = tslp->tblock; 438 savedtapea = spcl.c_tapea; 439 spcl.c_tapea = slp->tapea; 440 startnewtape(0); 441 spcl.c_tapea = savedtapea; 442 lastspclrec = savedtapea - 1; 443 } 444 size = (char *)ntb - (char *)q; 445 if (atomic(write, slp->fd, (char *)q, size) != size) { 446 perror(" DUMP: error writing command pipe"); 447 dumpabort(0); 448 } 449 slp->sent = 1; 450 if (++slp >= &slaves[SLAVES]) 451 slp = &slaves[0]; 452 453 q->count = 1; 454 455 if (prev->dblk != 0) { 456 /* 457 * If the last one was a disk block, make the 458 * first of this one be the last bit of that disk 459 * block... 460 */ 461 q->dblk = prev->dblk + 462 prev->count * (TP_BSIZE / DEV_BSIZE); 463 ntb = (union u_spcl *)tslp->tblock; 464 } else { 465 /* 466 * It wasn't a disk block. Copy the data to its 467 * new location in the buffer. 468 */ 469 q->dblk = 0; 470 *((union u_spcl *)tslp->tblock) = *ntb; 471 ntb = (union u_spcl *)tslp->tblock[1]; 472 } 473 } 474 slp->req[0] = *q; 475 nextblock = slp->tblock; 476 if (q->dblk == 0) 477 nextblock++; 478 trecno = 1; 479 480 /* 481 * Clear the first slaves' response. One hopes that it 482 * worked ok, otherwise the tape is much too short! 483 */ 484 if (slp->sent) { 485 if (atomic(read, slp->fd, (char *)&got, sizeof got) 486 != sizeof got) { 487 perror(" DUMP: error reading command pipe in master"); 488 dumpabort(0); 489 } 490 slp->sent = 0; 491 492 if (got != writesize) { 493 quit("EOT detected at start of the tape!\n"); 494 } 495 } 496 } 497 498 /* 499 * We implement taking and restoring checkpoints on the tape level. 500 * When each tape is opened, a new process is created by forking; this 501 * saves all of the necessary context in the parent. The child 502 * continues the dump; the parent waits around, saving the context. 503 * If the child returns X_REWRITE, then it had problems writing that tape; 504 * this causes the parent to fork again, duplicating the context, and 505 * everything continues as if nothing had happened. 506 */ 507 void 508 startnewtape(int top) 509 { 510 int parentpid; 511 int childpid; 512 int status; 513 int waitpid; 514 char *p; 515 #ifdef sunos 516 void (*interrupt_save)(); 517 #else 518 sig_t interrupt_save; 519 #endif 520 521 interrupt_save = signal(SIGINT, SIG_IGN); 522 parentpid = getpid(); 523 524 restore_check_point: 525 (void)signal(SIGINT, interrupt_save); 526 /* 527 * All signals are inherited... 528 */ 529 setproctitle(NULL); /* Restore the proctitle. */ 530 childpid = fork(); 531 if (childpid < 0) { 532 msg("Context save fork fails in parent %d\n", parentpid); 533 Exit(X_ABORT); 534 } 535 if (childpid != 0) { 536 /* 537 * PARENT: 538 * save the context by waiting 539 * until the child doing all of the work returns. 540 * don't catch the interrupt 541 */ 542 signal(SIGINT, SIG_IGN); 543 #ifdef TDEBUG 544 msg("Tape: %d; parent process: %d child process %d\n", 545 tapeno+1, parentpid, childpid); 546 #endif /* TDEBUG */ 547 while ((waitpid = wait(&status)) != childpid) 548 msg("Parent %d waiting for child %d has another child %d return\n", 549 parentpid, childpid, waitpid); 550 if (status & 0xFF) { 551 msg("Child %d returns LOB status %o\n", 552 childpid, status&0xFF); 553 } 554 status = (status >> 8) & 0xFF; 555 #ifdef TDEBUG 556 switch(status) { 557 case X_FINOK: 558 msg("Child %d finishes X_FINOK\n", childpid); 559 break; 560 case X_ABORT: 561 msg("Child %d finishes X_ABORT\n", childpid); 562 break; 563 case X_REWRITE: 564 msg("Child %d finishes X_REWRITE\n", childpid); 565 break; 566 default: 567 msg("Child %d finishes unknown %d\n", 568 childpid, status); 569 break; 570 } 571 #endif /* TDEBUG */ 572 switch(status) { 573 case X_FINOK: 574 Exit(X_FINOK); 575 case X_ABORT: 576 Exit(X_ABORT); 577 case X_REWRITE: 578 goto restore_check_point; 579 default: 580 msg("Bad return code from dump: %d\n", status); 581 Exit(X_ABORT); 582 } 583 /*NOTREACHED*/ 584 } else { /* we are the child; just continue */ 585 #ifdef TDEBUG 586 sleep(4); /* allow time for parent's message to get out */ 587 msg("Child on Tape %d has parent %d, my pid = %d\n", 588 tapeno+1, parentpid, getpid()); 589 #endif /* TDEBUG */ 590 /* 591 * If we have a name like "/dev/rmt0,/dev/rmt1", 592 * use the name before the comma first, and save 593 * the remaining names for subsequent volumes. 594 */ 595 tapeno++; /* current tape sequence */ 596 if (nexttape || strchr(tape, ',')) { 597 if (nexttape && *nexttape) 598 tape = nexttape; 599 if ((p = strchr(tape, ',')) != NULL) { 600 *p = '\0'; 601 nexttape = p + 1; 602 } else 603 nexttape = NULL; 604 msg("Dumping volume %d on %s\n", tapeno, tape); 605 } 606 #ifdef RDUMP 607 while ((tapefd = (host ? rmtopen(tape, 2) : 608 pipeout ? 1 : open(tape, O_WRONLY|O_CREAT, 0666))) < 0) 609 #else 610 while ((tapefd = (pipeout ? 1 : 611 open(tape, O_WRONLY|O_CREAT, 0666))) < 0) 612 #endif 613 { 614 msg("Cannot open output \"%s\".\n", tape); 615 if (!query("Do you want to retry the open?")) 616 dumpabort(0); 617 } 618 619 enslave(); /* Share open tape file descriptor with slaves */ 620 signal(SIGINFO, infosch); 621 622 asize = 0; 623 blocksthisvol = 0; 624 if (top) 625 newtape++; /* new tape signal */ 626 spcl.c_count = slp->count; 627 /* 628 * measure firstrec in TP_BSIZE units since restore doesn't 629 * know the correct ntrec value... 630 */ 631 spcl.c_firstrec = slp->firstrec; 632 spcl.c_volume++; 633 spcl.c_type = TS_TAPE; 634 spcl.c_flags |= DR_NEWHEADER; 635 writeheader((ino_t)slp->inode); 636 spcl.c_flags &=~ DR_NEWHEADER; 637 if (tapeno > 1) 638 msg("Volume %d begins with blocks from inode %d\n", 639 tapeno, slp->inode); 640 } 641 } 642 643 void 644 dumpabort(int signo) 645 { 646 647 if (master != 0 && master != getpid()) 648 /* Signals master to call dumpabort */ 649 (void) kill(master, SIGTERM); 650 else { 651 killall(); 652 msg("The ENTIRE dump is aborted.\n"); 653 } 654 #ifdef RDUMP 655 rmtclose(); 656 #endif 657 Exit(X_ABORT); 658 } 659 660 void 661 Exit(int status) 662 { 663 664 #ifdef TDEBUG 665 msg("pid = %d exits with status %d\n", getpid(), status); 666 #endif /* TDEBUG */ 667 exit(status); 668 } 669 670 /* 671 * proceed - handler for SIGUSR2, used to synchronize IO between the slaves. 672 */ 673 void 674 proceed(int signo) 675 { 676 677 if (ready) 678 longjmp(jmpbuf, 1); 679 caught++; 680 } 681 682 void 683 enslave(void) 684 { 685 int cmd[2]; 686 register int i, j; 687 688 master = getpid(); 689 690 signal(SIGTERM, dumpabort); /* Slave sends SIGTERM on dumpabort() */ 691 signal(SIGPIPE, sigpipe); 692 signal(SIGUSR1, tperror); /* Slave sends SIGUSR1 on tape errors */ 693 signal(SIGUSR2, proceed); /* Slave sends SIGUSR2 to next slave */ 694 695 for (i = 0; i < SLAVES; i++) { 696 if (i == slp - &slaves[0]) { 697 caught = 1; 698 } else { 699 caught = 0; 700 } 701 702 if (socketpair(AF_UNIX, SOCK_STREAM, 0, cmd) < 0 || 703 (slaves[i].pid = fork()) < 0) 704 quit("too many slaves, %d (recompile smaller): %s\n", 705 i, strerror(errno)); 706 707 slaves[i].fd = cmd[1]; 708 slaves[i].sent = 0; 709 if (slaves[i].pid == 0) { /* Slave starts up here */ 710 for (j = 0; j <= i; j++) 711 (void) close(slaves[j].fd); 712 signal(SIGINT, SIG_IGN); /* Master handles this */ 713 doslave(cmd[0], i); 714 Exit(X_FINOK); 715 } 716 } 717 718 for (i = 0; i < SLAVES; i++) 719 (void) atomic(write, slaves[i].fd, 720 (char *) &slaves[(i + 1) % SLAVES].pid, 721 sizeof slaves[0].pid); 722 723 master = 0; 724 } 725 726 void 727 killall(void) 728 { 729 register int i; 730 731 for (i = 0; i < SLAVES; i++) 732 if (slaves[i].pid > 0) { 733 (void) kill(slaves[i].pid, SIGKILL); 734 slaves[i].sent = 0; 735 } 736 } 737 738 /* 739 * Synchronization - each process has a lockfile, and shares file 740 * descriptors to the following process's lockfile. When our write 741 * completes, we release our lock on the following process's lock- 742 * file, allowing the following process to lock it and proceed. We 743 * get the lock back for the next cycle by swapping descriptors. 744 */ 745 static void 746 doslave(register int cmd, int slave_number) 747 { 748 register int nread; 749 int nextslave, size, wrote = 0, eot_count; 750 751 /* 752 * Need our own seek pointer. 753 */ 754 (void) close(diskfd); 755 if ((diskfd = open(disk, O_RDONLY)) < 0) 756 quit("slave couldn't reopen disk: %s\n", strerror(errno)); 757 758 /* 759 * Need the pid of the next slave in the loop... 760 */ 761 if ((nread = atomic(read, cmd, (char *)&nextslave, sizeof nextslave)) 762 != sizeof nextslave) { 763 quit("master/slave protocol botched - didn't get pid of next slave.\n"); 764 } 765 766 /* 767 * Get list of blocks to dump, read the blocks into tape buffer 768 */ 769 while ((nread = atomic(read, cmd, (char *)slp->req, reqsiz)) == reqsiz) { 770 register struct req *p = slp->req; 771 772 for (trecno = 0; trecno < ntrec; 773 trecno += p->count, p += p->count) { 774 if (p->dblk) { 775 bread(p->dblk, slp->tblock[trecno], 776 p->count * TP_BSIZE); 777 } else { 778 if (p->count != 1 || atomic(read, cmd, 779 (char *)slp->tblock[trecno], 780 TP_BSIZE) != TP_BSIZE) 781 quit("master/slave protocol botched.\n"); 782 } 783 } 784 if (setjmp(jmpbuf) == 0) { 785 ready = 1; 786 if (!caught) 787 (void) pause(); 788 } 789 ready = 0; 790 caught = 0; 791 792 /* Try to write the data... */ 793 eot_count = 0; 794 size = 0; 795 796 while (eot_count < 10 && size < writesize) { 797 #ifdef RDUMP 798 if (host) 799 wrote = rmtwrite(slp->tblock[0]+size, 800 writesize-size); 801 else 802 #endif 803 wrote = write(tapefd, slp->tblock[0]+size, 804 writesize-size); 805 #ifdef WRITEDEBUG 806 printf("slave %d wrote %d\n", slave_number, wrote); 807 #endif 808 if (wrote < 0) 809 break; 810 if (wrote == 0) 811 eot_count++; 812 size += wrote; 813 } 814 815 #ifdef WRITEDEBUG 816 if (size != writesize) 817 printf("slave %d only wrote %d out of %d bytes and gave up.\n", 818 slave_number, size, writesize); 819 #endif 820 821 /* 822 * Handle ENOSPC as an EOT condition. 823 */ 824 if (wrote < 0 && errno == ENOSPC) { 825 wrote = 0; 826 eot_count++; 827 } 828 829 if (eot_count > 0) 830 size = 0; 831 832 if (wrote < 0) { 833 (void) kill(master, SIGUSR1); 834 for (;;) 835 (void) sigpause(0); 836 } else { 837 /* 838 * pass size of write back to master 839 * (for EOT handling) 840 */ 841 (void) atomic(write, cmd, (char *)&size, sizeof size); 842 } 843 844 /* 845 * If partial write, don't want next slave to go. 846 * Also jolts him awake. 847 */ 848 (void) kill(nextslave, SIGUSR2); 849 } 850 if (nread != 0) 851 quit("error reading command pipe: %s\n", strerror(errno)); 852 } 853 854 /* 855 * Since a read from a pipe may not return all we asked for, 856 * or a write may not write all we ask if we get a signal, 857 * loop until the count is satisfied (or error). 858 */ 859 static int 860 atomic(ssize_t (*func)(), int fd, char *buf, int count) 861 { 862 int got, need = count; 863 864 while ((got = (*func)(fd, buf, need)) > 0 && (need -= got) > 0) 865 buf += got; 866 return (got < 0 ? got : count - need); 867 } 868