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. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * @(#)tape.c 8.4 (Berkeley) 5/1/95 30 * $FreeBSD: src/sbin/dump/tape.c,v 1.12.2.3 2002/02/23 22:32:51 iedowse Exp $ 31 */ 32 33 #include <sys/param.h> 34 #include <sys/socket.h> 35 #include <sys/time.h> 36 #include <sys/wait.h> 37 #include <sys/stat.h> 38 #include <vfs/ufs/dinode.h> 39 #include <vfs/ufs/fs.h> 40 41 #include <protocols/dumprestore.h> 42 43 #include <errno.h> 44 #include <fcntl.h> 45 #include <setjmp.h> 46 #include <signal.h> 47 #include <stdio.h> 48 #include <stdlib.h> 49 #include <string.h> 50 #include <unistd.h> 51 52 #include "dump.h" 53 54 static int writesize; /* size of malloc()ed buffer for tape */ 55 static long lastspclrec = -1; /* tape block number of last written header */ 56 static int trecno = 0; /* next record to write in current block */ 57 static long blocksthisvol; /* number of blocks on current output file */ 58 static const char *nexttape; 59 static int tapeno = 0; /* current tape number */ 60 61 static int atomic_read(int, void *, int); 62 static int atomic_write(int, const void *, int); 63 #ifdef WRITEDEBUG 64 static void doslave(int, int); 65 #else 66 static void doslave(int); 67 #endif 68 static void enslave(void); 69 static void flushtape(void); 70 static void killall(void); 71 static void rollforward(void); 72 73 /* 74 * Concurrent dump mods (Caltech) - disk block reading and tape writing 75 * are exported to several slave processes. While one slave writes the 76 * tape, the others read disk blocks; they pass control of the tape in 77 * a ring via signals. The parent process traverses the filesystem and 78 * sends writeheader()'s and lists of daddr's to the slaves via pipes. 79 * The following structure defines the instruction packets sent to slaves. 80 */ 81 struct req { 82 daddr_t dblk; 83 int count; 84 }; 85 int reqsiz; 86 87 #define SLAVES 3 /* 1 slave writing, 1 reading, 1 for slack */ 88 struct slave { 89 int tapea; /* header number at start of this chunk */ 90 int count; /* count to next header (used for TS_TAPE */ 91 /* after EOT) */ 92 int inode; /* inode that we are currently dealing with */ 93 int fd; /* FD for this slave */ 94 int pid; /* PID for this slave */ 95 int sent; /* 1 == we've sent this slave requests */ 96 int firstrec; /* record number of this block */ 97 char (*tblock)[TP_BSIZE]; /* buffer for data blocks */ 98 struct req *req; /* buffer for requests */ 99 } slaves[SLAVES+1]; 100 struct slave *slp; 101 102 char (*nextblock)[TP_BSIZE]; 103 104 int master; /* pid of master, for sending error signals */ 105 int tenths; /* length of tape used per block written */ 106 static int caught; /* have we caught the signal to proceed? */ 107 static int ready; /* have we reached the lock point without having */ 108 /* received the SIGUSR2 signal from the prev slave? */ 109 static jmp_buf jmpbuf; /* where to jump to if we are ready when the */ 110 /* SIGUSR2 arrives from the previous slave */ 111 112 int 113 alloctape(void) 114 { 115 int pgoff = getpagesize() - 1; 116 char *buf; 117 int i; 118 119 writesize = ntrec * TP_BSIZE; 120 reqsiz = (ntrec + 1) * sizeof(struct req); 121 /* 122 * CDC 92181's and 92185's make 0.8" gaps in 1600-bpi start/stop mode 123 * (see DEC TU80 User's Guide). The shorter gaps of 6250-bpi require 124 * repositioning after stopping, i.e, streaming mode, where the gap is 125 * variable, 0.30" to 0.45". The gap is maximal when the tape stops. 126 */ 127 if (blocksperfile == 0 && !unlimited) 128 tenths = writesize / density + 129 (cartridge ? 16 : density == 625 ? 5 : 8); 130 /* 131 * Allocate tape buffer contiguous with the array of instruction 132 * packets, so flushtape() can write them together with one write(). 133 * Align tape buffer on page boundary to speed up tape write(). 134 */ 135 for (i = 0; i <= SLAVES; i++) { 136 buf = (char *) 137 malloc((unsigned)(reqsiz + writesize + pgoff + TP_BSIZE)); 138 if (buf == NULL) 139 return(0); 140 slaves[i].tblock = (char (*)[TP_BSIZE]) 141 (((long)&buf[ntrec + 1] + pgoff) &~ pgoff); 142 slaves[i].req = (struct req *)slaves[i].tblock - ntrec - 1; 143 } 144 slp = &slaves[0]; 145 slp->count = 1; 146 slp->tapea = 0; 147 slp->firstrec = 0; 148 nextblock = slp->tblock; 149 return(1); 150 } 151 152 void 153 writerec(const void *dp, int isspcl) 154 { 155 156 slp->req[trecno].dblk = (daddr_t)0; 157 slp->req[trecno].count = 1; 158 bcopy(dp, *(nextblock)++, sizeof (union u_spcl)); 159 if (isspcl) 160 lastspclrec = spcl.c_tapea; 161 trecno++; 162 spcl.c_tapea++; 163 if (trecno >= ntrec) 164 flushtape(); 165 } 166 167 void 168 dumpblock(daddr_t blkno, int size) 169 { 170 int avail, tpblks, dblkno; 171 172 dblkno = fsbtodb(sblock, blkno); 173 tpblks = size >> tp_bshift; 174 while ((avail = MIN(tpblks, ntrec - trecno)) > 0) { 175 slp->req[trecno].dblk = dblkno; 176 slp->req[trecno].count = avail; 177 trecno += avail; 178 spcl.c_tapea += avail; 179 if (trecno >= ntrec) 180 flushtape(); 181 dblkno += avail << (tp_bshift - dev_bshift); 182 tpblks -= avail; 183 } 184 } 185 186 int nogripe = 0; 187 188 static void 189 tperror(int signo __unused) 190 { 191 192 if (pipeout) { 193 msg("write error on %s\n", tape); 194 quit("Cannot recover\n"); 195 /* NOTREACHED */ 196 } 197 msg("write error %ld blocks into volume %d\n", blocksthisvol, tapeno); 198 broadcast("DUMP WRITE ERROR!\n"); 199 if (!query("Do you want to restart?")) 200 dumpabort(0); 201 msg("Closing this volume. Prepare to restart with new media;\n"); 202 msg("this dump volume will be rewritten.\n"); 203 killall(); 204 nogripe = 1; 205 close_rewind(); 206 Exit(X_REWRITE); 207 } 208 209 static void 210 sigpipe(int signo __unused) 211 { 212 213 quit("Broken pipe\n"); 214 } 215 216 static void 217 flushtape(void) 218 { 219 int i, blks, got; 220 long lastfirstrec; 221 222 int siz = (char *)nextblock - (char *)slp->req; 223 224 slp->req[trecno].count = 0; /* Sentinel */ 225 226 if (atomic_write(slp->fd, slp->req, siz) != siz) 227 quit("error writing command pipe: %s\n", strerror(errno)); 228 slp->sent = 1; /* we sent a request, read the response later */ 229 230 lastfirstrec = slp->firstrec; 231 232 if (++slp >= &slaves[SLAVES]) 233 slp = &slaves[0]; 234 235 /* Read results back from next slave */ 236 if (slp->sent) { 237 if (atomic_read(slp->fd, &got, sizeof got) 238 != sizeof got) { 239 perror(" DUMP: error reading command pipe in master"); 240 dumpabort(0); 241 } 242 slp->sent = 0; 243 244 /* Check for end of tape */ 245 if (got < writesize) { 246 msg("End of tape detected\n"); 247 248 /* 249 * Drain the results, don't care what the values were. 250 * If we read them here then trewind won't... 251 */ 252 for (i = 0; i < SLAVES; i++) { 253 if (slaves[i].sent) { 254 if (atomic_read(slaves[i].fd, 255 &got, sizeof got) 256 != sizeof got) { 257 perror(" DUMP: error reading command pipe in master"); 258 dumpabort(0); 259 } 260 slaves[i].sent = 0; 261 } 262 } 263 264 close_rewind(); 265 rollforward(); 266 return; 267 } 268 } 269 270 blks = 0; 271 if (spcl.c_type != TS_END) { 272 for (i = 0; i < spcl.c_count; i++) 273 if (spcl.c_addr[i] != 0) 274 blks++; 275 } 276 slp->count = lastspclrec + blks + 1 - spcl.c_tapea; 277 slp->tapea = spcl.c_tapea; 278 slp->firstrec = lastfirstrec + ntrec; 279 slp->inode = curino; 280 nextblock = slp->tblock; 281 trecno = 0; 282 asize += tenths; 283 blockswritten += ntrec; 284 blocksthisvol += ntrec; 285 if (!pipeout && !unlimited && (blocksperfile ? 286 (blocksthisvol >= blocksperfile) : (asize > tsize))) { 287 close_rewind(); 288 startnewtape(0); 289 } 290 timeest(); 291 } 292 293 void 294 trewind(void) 295 { 296 struct stat sb; 297 int f; 298 int got; 299 300 for (f = 0; f < SLAVES; f++) { 301 /* 302 * Drain the results, but unlike EOT we DO (or should) care 303 * what the return values were, since if we detect EOT after 304 * we think we've written the last blocks to the tape anyway, 305 * we have to replay those blocks with rollforward. 306 * 307 * fixme: punt for now. 308 */ 309 if (slaves[f].sent) { 310 if (atomic_read(slaves[f].fd, &got, sizeof got) 311 != sizeof got) { 312 perror(" DUMP: error reading command pipe in master"); 313 dumpabort(0); 314 } 315 slaves[f].sent = 0; 316 if (got != writesize) { 317 msg("EOT detected in last 2 tape records!\n"); 318 msg("Use a longer tape, decrease the size estimate\n"); 319 quit("or use no size estimate at all.\n"); 320 } 321 } 322 close(slaves[f].fd); 323 } 324 while (wait(NULL) >= 0) /* wait for any signals from slaves */ 325 /* void */; 326 327 if (pipeout) 328 return; 329 330 msg("Closing %s\n", tape); 331 332 #ifdef RDUMP 333 if (host) { 334 rmtclose(); 335 while (rmtopen(tape, 0) < 0) 336 sleep(10); 337 rmtclose(); 338 return; 339 } 340 #endif 341 if (fstat(tapefd, &sb) == 0 && S_ISFIFO(sb.st_mode)) { 342 close(tapefd); 343 return; 344 } 345 close(tapefd); 346 while ((f = open(tape, 0)) < 0) 347 sleep (10); 348 close(f); 349 } 350 351 void 352 close_rewind(void) 353 { 354 time_t tstart_changevol, tend_changevol; 355 356 trewind(); 357 if (nexttape) 358 return; 359 time((time_t *)&(tstart_changevol)); 360 if (!nogripe) { 361 msg("Change Volumes: Mount volume #%d\n", tapeno+1); 362 broadcast("CHANGE DUMP VOLUMES!\a\a\n"); 363 } 364 while (!query("Is the new volume mounted and ready to go?")) 365 if (query("Do you want to abort?")) { 366 dumpabort(0); 367 /*NOTREACHED*/ 368 } 369 time((time_t *)&(tend_changevol)); 370 if ((tstart_changevol != (time_t)-1) && (tend_changevol != (time_t)-1)) 371 tstart_writing += (tend_changevol - tstart_changevol); 372 } 373 374 void 375 rollforward(void) 376 { 377 struct req *p, *q, *prev; 378 struct slave *tslp; 379 int i, size, savedtapea, got; 380 union u_spcl *ntb, *otb; 381 tslp = &slaves[SLAVES]; 382 ntb = (union u_spcl *)tslp->tblock[1]; 383 384 /* 385 * Each of the N slaves should have requests that need to 386 * be replayed on the next tape. Use the extra slave buffers 387 * (slaves[SLAVES]) to construct request lists to be sent to 388 * each slave in turn. 389 */ 390 for (i = 0; i < SLAVES; i++) { 391 q = &tslp->req[1]; 392 otb = (union u_spcl *)slp->tblock; 393 394 /* 395 * For each request in the current slave, copy it to tslp. 396 */ 397 398 prev = NULL; 399 for (p = slp->req; p->count > 0; p += p->count) { 400 *q = *p; 401 if (p->dblk == 0) 402 *ntb++ = *otb++; /* copy the datablock also */ 403 prev = q; 404 q += q->count; 405 } 406 if (prev == NULL) 407 quit("rollforward: protocol botch"); 408 if (prev->dblk != 0) 409 prev->count -= 1; 410 else 411 ntb--; 412 q -= 1; 413 q->count = 0; 414 q = &tslp->req[0]; 415 if (i == 0) { 416 q->dblk = 0; 417 q->count = 1; 418 trecno = 0; 419 nextblock = tslp->tblock; 420 savedtapea = spcl.c_tapea; 421 spcl.c_tapea = slp->tapea; 422 startnewtape(0); 423 spcl.c_tapea = savedtapea; 424 lastspclrec = savedtapea - 1; 425 } 426 size = (char *)ntb - (char *)q; 427 if (atomic_write(slp->fd, q, size) != size) { 428 perror(" DUMP: error writing command pipe"); 429 dumpabort(0); 430 } 431 slp->sent = 1; 432 if (++slp >= &slaves[SLAVES]) 433 slp = &slaves[0]; 434 435 q->count = 1; 436 437 if (prev->dblk != 0) { 438 /* 439 * If the last one was a disk block, make the 440 * first of this one be the last bit of that disk 441 * block... 442 */ 443 q->dblk = prev->dblk + 444 prev->count * (TP_BSIZE / DEV_BSIZE); 445 ntb = (union u_spcl *)tslp->tblock; 446 } else { 447 /* 448 * It wasn't a disk block. Copy the data to its 449 * new location in the buffer. 450 */ 451 q->dblk = 0; 452 *((union u_spcl *)tslp->tblock) = *ntb; 453 ntb = (union u_spcl *)tslp->tblock[1]; 454 } 455 } 456 slp->req[0] = *q; 457 nextblock = slp->tblock; 458 if (q->dblk == 0) 459 nextblock++; 460 trecno = 1; 461 462 /* 463 * Clear the first slaves' response. One hopes that it 464 * worked ok, otherwise the tape is much too short! 465 */ 466 if (slp->sent) { 467 if (atomic_read(slp->fd, &got, sizeof got) 468 != sizeof got) { 469 perror(" DUMP: error reading command pipe in master"); 470 dumpabort(0); 471 } 472 slp->sent = 0; 473 474 if (got != writesize) { 475 quit("EOT detected at start of the tape!\n"); 476 } 477 } 478 } 479 480 /* 481 * We implement taking and restoring checkpoints on the tape level. 482 * When each tape is opened, a new process is created by forking; this 483 * saves all of the necessary context in the parent. The child 484 * continues the dump; the parent waits around, saving the context. 485 * If the child returns X_REWRITE, then it had problems writing that tape; 486 * this causes the parent to fork again, duplicating the context, and 487 * everything continues as if nothing had happened. 488 */ 489 void 490 startnewtape(int top) 491 { 492 int parentpid; 493 int childpid; 494 int status; 495 int wait_pid; 496 char *p; 497 sig_t interrupt_save; 498 499 interrupt_save = signal(SIGINT, SIG_IGN); 500 parentpid = getpid(); 501 502 restore_check_point: 503 signal(SIGINT, interrupt_save); 504 /* 505 * All signals are inherited... 506 */ 507 setproctitle(NULL); /* Restore the proctitle. */ 508 childpid = fork(); 509 if (childpid < 0) { 510 msg("Context save fork fails in parent %d\n", parentpid); 511 Exit(X_ABORT); 512 } 513 if (childpid != 0) { 514 /* 515 * PARENT: 516 * save the context by waiting 517 * until the child doing all of the work returns. 518 * don't catch the interrupt 519 */ 520 signal(SIGINT, SIG_IGN); 521 #ifdef TDEBUG 522 msg("Tape: %d; parent process: %d child process %d\n", 523 tapeno+1, parentpid, childpid); 524 #endif /* TDEBUG */ 525 while ((wait_pid = wait(&status)) != childpid) 526 msg("Parent %d waiting for child %d has another child %d return\n", 527 parentpid, childpid, wait_pid); 528 if (status & 0xFF) { 529 msg("Child %d returns LOB status %o\n", 530 childpid, status&0xFF); 531 } 532 status = (status >> 8) & 0xFF; 533 #ifdef TDEBUG 534 switch(status) { 535 case X_FINOK: 536 msg("Child %d finishes X_FINOK\n", childpid); 537 break; 538 case X_ABORT: 539 msg("Child %d finishes X_ABORT\n", childpid); 540 break; 541 case X_REWRITE: 542 msg("Child %d finishes X_REWRITE\n", childpid); 543 break; 544 default: 545 msg("Child %d finishes unknown %d\n", 546 childpid, status); 547 break; 548 } 549 #endif /* TDEBUG */ 550 switch(status) { 551 case X_FINOK: 552 Exit(X_FINOK); 553 case X_ABORT: 554 Exit(X_ABORT); 555 case X_REWRITE: 556 goto restore_check_point; 557 default: 558 msg("Bad return code from dump: %d\n", status); 559 Exit(X_ABORT); 560 } 561 /*NOTREACHED*/ 562 } else { /* we are the child; just continue */ 563 #ifdef TDEBUG 564 sleep(4); /* allow time for parent's message to get out */ 565 msg("Child on Tape %d has parent %d, my pid = %d\n", 566 tapeno+1, parentpid, getpid()); 567 #endif /* TDEBUG */ 568 /* 569 * If we have a name like "/dev/rmt0,/dev/rmt1", 570 * use the name before the comma first, and save 571 * the remaining names for subsequent volumes. 572 */ 573 tapeno++; /* current tape sequence */ 574 if (nexttape || strchr(tape, ',')) { 575 if (nexttape && *nexttape) 576 tape = nexttape; 577 if ((p = strchr(tape, ',')) != NULL) { 578 *p = '\0'; 579 nexttape = p + 1; 580 } else 581 nexttape = NULL; 582 msg("Dumping volume %d on %s\n", tapeno, tape); 583 } 584 #ifdef RDUMP 585 while ((tapefd = (host ? rmtopen(tape, 2) : 586 pipeout ? 1 : open(tape, O_WRONLY|O_CREAT, 0666))) < 0) 587 #else 588 while ((tapefd = (pipeout ? 1 : 589 open(tape, O_WRONLY|O_CREAT, 0666))) < 0) 590 #endif 591 { 592 msg("Cannot open output \"%s\".\n", tape); 593 if (!query("Do you want to retry the open?")) 594 dumpabort(0); 595 } 596 597 enslave(); /* Share open tape file descriptor with slaves */ 598 signal(SIGINFO, infosch); 599 600 asize = 0; 601 blocksthisvol = 0; 602 if (top) 603 newtape++; /* new tape signal */ 604 spcl.c_count = slp->count; 605 /* 606 * measure firstrec in TP_BSIZE units since restore doesn't 607 * know the correct ntrec value... 608 */ 609 spcl.c_firstrec = slp->firstrec; 610 spcl.c_volume++; 611 spcl.c_type = TS_TAPE; 612 spcl.c_flags |= DR_NEWHEADER; 613 writeheader((ufs1_ino_t)slp->inode); 614 spcl.c_flags &=~ DR_NEWHEADER; 615 if (tapeno > 1) 616 msg("Volume %d begins with blocks from inode %d\n", 617 tapeno, slp->inode); 618 } 619 } 620 621 void 622 dumpabort(int signo __unused) 623 { 624 625 if (master != 0 && master != getpid()) 626 /* Signals master to call dumpabort */ 627 kill(master, SIGTERM); 628 else { 629 killall(); 630 msg("The ENTIRE dump is aborted.\n"); 631 } 632 #ifdef RDUMP 633 rmtclose(); 634 #endif 635 Exit(X_ABORT); 636 } 637 638 void 639 Exit(int status) 640 { 641 642 #ifdef TDEBUG 643 msg("pid = %d exits with status %d\n", getpid(), status); 644 #endif /* TDEBUG */ 645 exit(status); 646 } 647 648 /* 649 * proceed - handler for SIGUSR2, used to synchronize IO between the slaves. 650 */ 651 static void 652 proceed(int signo __unused) 653 { 654 655 if (ready) 656 longjmp(jmpbuf, 1); 657 caught++; 658 } 659 660 static void 661 enslave(void) 662 { 663 int cmd[2]; 664 int i, j; 665 666 master = getpid(); 667 668 signal(SIGTERM, dumpabort); /* Slave sends SIGTERM on dumpabort() */ 669 signal(SIGPIPE, sigpipe); 670 signal(SIGUSR1, tperror); /* Slave sends SIGUSR1 on tape errors */ 671 signal(SIGUSR2, proceed); /* Slave sends SIGUSR2 to next slave */ 672 673 for (i = 0; i < SLAVES; i++) { 674 if (i == slp - &slaves[0]) { 675 caught = 1; 676 } else { 677 caught = 0; 678 } 679 680 if (socketpair(AF_UNIX, SOCK_STREAM, 0, cmd) < 0 || 681 (slaves[i].pid = fork()) < 0) 682 quit("too many slaves, %d (recompile smaller): %s\n", 683 i, strerror(errno)); 684 685 slaves[i].fd = cmd[1]; 686 slaves[i].sent = 0; 687 if (slaves[i].pid == 0) { /* Slave starts up here */ 688 for (j = 0; j <= i; j++) 689 close(slaves[j].fd); 690 signal(SIGINT, SIG_IGN); /* Master handles this */ 691 #ifdef WRITEDEBUG 692 doslave(cmd[0], i); 693 #else 694 doslave(cmd[0]); 695 #endif 696 Exit(X_FINOK); 697 } 698 } 699 700 for (i = 0; i < SLAVES; i++) 701 atomic_write(slaves[i].fd, &slaves[(i + 1) % SLAVES].pid, 702 sizeof slaves[0].pid); 703 704 master = 0; 705 } 706 707 void 708 killall(void) 709 { 710 int i; 711 712 for (i = 0; i < SLAVES; i++) 713 if (slaves[i].pid > 0) { 714 kill(slaves[i].pid, SIGKILL); 715 slaves[i].sent = 0; 716 } 717 } 718 719 /* 720 * Synchronization - each process has a lockfile, and shares file 721 * descriptors to the following process's lockfile. When our write 722 * completes, we release our lock on the following process's lock- 723 * file, allowing the following process to lock it and proceed. We 724 * get the lock back for the next cycle by swapping descriptors. 725 */ 726 static void 727 #ifdef WRITEDEBUG 728 doslave(int cmd, int slave_number) 729 #else 730 doslave(int cmd) 731 #endif 732 { 733 int nread; 734 int nextslave, size, wrote, eot_count; 735 736 /* 737 * Need our own seek pointer. 738 */ 739 close(diskfd); 740 if ((diskfd = open(disk, O_RDONLY)) < 0) 741 quit("slave couldn't reopen disk: %s\n", strerror(errno)); 742 743 /* 744 * Need the pid of the next slave in the loop... 745 */ 746 if ((nread = atomic_read(cmd, &nextslave, sizeof nextslave)) 747 != sizeof nextslave) { 748 quit("master/slave protocol botched - didn't get pid of next slave.\n"); 749 } 750 751 /* 752 * Get list of blocks to dump, read the blocks into tape buffer 753 */ 754 while ((nread = atomic_read(cmd, slp->req, reqsiz)) == reqsiz) { 755 struct req *p = slp->req; 756 757 for (trecno = 0; trecno < ntrec; 758 trecno += p->count, p += p->count) { 759 if (p->dblk) { 760 bread(p->dblk, slp->tblock[trecno], 761 p->count * TP_BSIZE); 762 } else { 763 if (p->count != 1 || 764 atomic_read(cmd, slp->tblock[trecno], 765 TP_BSIZE) != TP_BSIZE) 766 quit("master/slave protocol botched.\n"); 767 } 768 } 769 if (setjmp(jmpbuf) == 0) { 770 ready = 1; 771 if (!caught) 772 pause(); 773 } 774 ready = 0; 775 caught = 0; 776 777 /* Try to write the data... */ 778 eot_count = 0; 779 size = 0; 780 wrote = 0; 781 782 while (eot_count < 10 && size < writesize) { 783 #ifdef RDUMP 784 if (host) 785 wrote = rmtwrite(slp->tblock[0]+size, 786 writesize-size); 787 else 788 #endif 789 wrote = write(tapefd, slp->tblock[0]+size, 790 writesize-size); 791 #ifdef WRITEDEBUG 792 printf("slave %d wrote %d\n", slave_number, wrote); 793 #endif 794 if (wrote < 0) 795 break; 796 if (wrote == 0) 797 eot_count++; 798 size += wrote; 799 } 800 801 #ifdef WRITEDEBUG 802 if (size != writesize) 803 printf("slave %d only wrote %d out of %d bytes and gave up.\n", 804 slave_number, size, writesize); 805 #endif 806 807 /* 808 * Handle ENOSPC as an EOT condition. 809 */ 810 if (wrote < 0 && errno == ENOSPC) { 811 wrote = 0; 812 eot_count++; 813 } 814 815 if (eot_count > 0) 816 size = 0; 817 818 if (wrote < 0) { 819 kill(master, SIGUSR1); 820 for (;;) 821 sigpause(0); 822 } else { 823 /* 824 * pass size of write back to master 825 * (for EOT handling) 826 */ 827 atomic_write(cmd, &size, sizeof size); 828 } 829 830 /* 831 * If partial write, don't want next slave to go. 832 * Also jolts him awake. 833 */ 834 kill(nextslave, SIGUSR2); 835 } 836 if (nread != 0) 837 quit("error reading command pipe: %s\n", strerror(errno)); 838 } 839 840 static int 841 atomic_read(int fd, void *buf, int count) 842 { 843 int got, need = count; 844 845 while ((got = read(fd, buf, need)) > 0 && (need -= got) > 0) 846 buf = (uint8_t *)buf + got; 847 return (got < 0 ? got : count - need); 848 } 849 850 static int 851 atomic_write(int fd, const void *buf, int count) 852 { 853 int got, need = count; 854 855 while ((got = write(fd, buf, need)) > 0 && (need -= got) > 0) 856 buf = (const uint8_t *)buf + got; 857 return (got < 0 ? got : count - need); 858 } 859