tape.c revision 1.2
1 /*- 2 * Copyright (c) 1980, 1991 The Regents of the University of California. 3 * 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 34 #ifndef lint 35 /* from: static char sccsid[] = "@(#)tape.c 5.25 (Berkeley) 7/16/92"; */ 36 static char *rcsid = "$Id: tape.c,v 1.2 1994/03/09 01:14:43 cgd Exp $"; 37 #endif /* not lint */ 38 39 #ifdef sunos 40 #include <sys/param.h> 41 #include <stdio.h> 42 #include <ctype.h> 43 #include <sys/stat.h> 44 #include <ufs/fs.h> 45 #else 46 #include <sys/param.h> 47 #include <sys/wait.h> 48 #include <ufs/fs.h> 49 #endif 50 #include <sys/time.h> 51 #include <ufs/dinode.h> 52 #include <signal.h> 53 #include <fcntl.h> 54 #include <protocols/dumprestore.h> 55 #include <errno.h> 56 #include <setjmp.h> 57 #ifdef __STDC__ 58 #include <unistd.h> 59 #include <stdlib.h> 60 #include <string.h> 61 #endif 62 #include <sys/socket.h> 63 #include "dump.h" 64 #include "pathnames.h" 65 66 int writesize; /* size of malloc()ed buffer for tape */ 67 long lastspclrec = -1; /* tape block number of last written header */ 68 int trecno = 0; /* next record to write in current block */ 69 extern long blocksperfile; /* number of blocks per output file */ 70 long blocksthisvol; /* number of blocks on current output file */ 71 extern int ntrec; /* blocking factor on tape */ 72 extern int cartridge; 73 extern char *host; 74 char *nexttape; 75 #ifdef RDUMP 76 int rmtopen(), rmtwrite(); 77 void rmtclose(); 78 #endif 79 void rollforward(); 80 int atomic(); 81 void doslave(), enslave(), flushtape(), killall(); 82 83 /* 84 * Concurrent dump mods (Caltech) - disk block reading and tape writing 85 * are exported to several slave processes. While one slave writes the 86 * tape, the others read disk blocks; they pass control of the tape in 87 * a ring via signals. The parent process traverses the filesystem and 88 * sends writeheader()'s and lists of daddr's to the slaves via pipes. 89 * The following structure defines the instruction packets sent to slaves. 90 */ 91 struct req { 92 daddr_t dblk; 93 int count; 94 }; 95 int reqsiz; 96 97 #define SLAVES 3 /* 1 slave writing, 1 reading, 1 for slack */ 98 struct slave { 99 int tapea; /* header number at start of this chunk */ 100 int count; /* count to next header (used for TS_TAPE */ 101 /* after EOT) */ 102 int inode; /* inode that we are currently dealing with */ 103 int fd; /* FD for this slave */ 104 int pid; /* PID for this slave */ 105 int sent; /* 1 == we've sent this slave requests */ 106 int firstrec; /* record number of this block */ 107 char (*tblock)[TP_BSIZE]; /* buffer for data blocks */ 108 struct req *req; /* buffer for requests */ 109 } slaves[SLAVES+1]; 110 struct slave *slp; 111 112 char (*nextblock)[TP_BSIZE]; 113 114 int master; /* pid of master, for sending error signals */ 115 int tenths; /* length of tape used per block written */ 116 static int caught; /* have we caught the signal to proceed? */ 117 static int ready; /* have we reached the lock point without having */ 118 /* received the SIGUSR2 signal from the prev slave? */ 119 static jmp_buf jmpbuf; /* where to jump to if we are ready when the */ 120 /* SIGUSR2 arrives from the previous slave */ 121 122 int 123 alloctape() 124 { 125 int pgoff = getpagesize() - 1; 126 char *buf; 127 int i; 128 129 writesize = ntrec * TP_BSIZE; 130 reqsiz = (ntrec + 1) * sizeof(struct req); 131 /* 132 * CDC 92181's and 92185's make 0.8" gaps in 1600-bpi start/stop mode 133 * (see DEC TU80 User's Guide). The shorter gaps of 6250-bpi require 134 * repositioning after stopping, i.e, streaming mode, where the gap is 135 * variable, 0.30" to 0.45". The gap is maximal when the tape stops. 136 */ 137 if (blocksperfile == 0) 138 tenths = writesize / density + 139 (cartridge ? 16 : density == 625 ? 5 : 8); 140 /* 141 * Allocate tape buffer contiguous with the array of instruction 142 * packets, so flushtape() can write them together with one write(). 143 * Align tape buffer on page boundary to speed up tape write(). 144 */ 145 for (i = 0; i <= SLAVES; i++) { 146 buf = (char *) 147 malloc((unsigned)(reqsiz + writesize + pgoff + TP_BSIZE)); 148 if (buf == NULL) 149 return(0); 150 slaves[i].tblock = (char (*)[TP_BSIZE]) 151 (((long)&buf[ntrec + 1] + pgoff) &~ pgoff); 152 slaves[i].req = (struct req *)slaves[i].tblock - ntrec - 1; 153 } 154 slp = &slaves[0]; 155 slp->count = 1; 156 slp->tapea = 0; 157 slp->firstrec = 0; 158 nextblock = slp->tblock; 159 return(1); 160 } 161 162 void 163 writerec(dp, isspcl) 164 char *dp; 165 int isspcl; 166 { 167 168 slp->req[trecno].dblk = (daddr_t)0; 169 slp->req[trecno].count = 1; 170 *(union u_spcl *)(*(nextblock)++) = *(union u_spcl *)dp; 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(blkno, size) 181 daddr_t blkno; 182 int size; 183 { 184 int avail, tpblks, dblkno; 185 186 dblkno = fsbtodb(sblock, blkno); 187 tpblks = size >> tp_bshift; 188 while ((avail = MIN(tpblks, ntrec - trecno)) > 0) { 189 slp->req[trecno].dblk = dblkno; 190 slp->req[trecno].count = avail; 191 trecno += avail; 192 spcl.c_tapea += avail; 193 if (trecno >= ntrec) 194 flushtape(); 195 dblkno += avail << (tp_bshift - dev_bshift); 196 tpblks -= avail; 197 } 198 } 199 200 int nogripe = 0; 201 202 void 203 tperror(signo) 204 int signo; 205 { 206 207 if (pipeout) { 208 msg("write error on %s\n", tape); 209 quit("Cannot recover\n"); 210 /* NOTREACHED */ 211 } 212 msg("write error %d blocks into volume %d\n", blocksthisvol, tapeno); 213 broadcast("DUMP WRITE ERROR!\n"); 214 if (!query("Do you want to restart?")) 215 dumpabort(0); 216 msg("Closing this volume. Prepare to restart with new media;\n"); 217 msg("this dump volume will be rewritten.\n"); 218 killall(); 219 nogripe = 1; 220 close_rewind(); 221 Exit(X_REWRITE); 222 } 223 224 void 225 sigpipe(signo) 226 int signo; 227 { 228 229 quit("Broken pipe\n"); 230 } 231 232 void 233 flushtape() 234 { 235 int i, blks, got; 236 long lastfirstrec; 237 #ifndef __STDC__ 238 int write(), read(); 239 #endif 240 241 int siz = (char *)nextblock - (char *)slp->req; 242 243 slp->req[trecno].count = 0; /* Sentinel */ 244 245 if (atomic(write, slp->fd, (char *)slp->req, siz) != siz) 246 quit("error writing command pipe: %s\n", strerror(errno)); 247 slp->sent = 1; /* we sent a request, read the response later */ 248 249 lastfirstrec = slp->firstrec; 250 251 if (++slp >= &slaves[SLAVES]) 252 slp = &slaves[0]; 253 254 /* Read results back from next slave */ 255 if (slp->sent) { 256 if (atomic(read, slp->fd, (char *)&got, sizeof got) 257 != sizeof got) { 258 perror(" DUMP: error reading command pipe in master"); 259 dumpabort(0); 260 } 261 slp->sent = 0; 262 263 /* Check for end of tape */ 264 if (got < writesize) { 265 msg("End of tape detected\n"); 266 267 /* 268 * Drain the results, don't care what the values were. 269 * If we read them here then trewind won't... 270 */ 271 for (i = 0; i < SLAVES; i++) { 272 if (slaves[i].sent) { 273 if (atomic(read, slaves[i].fd, 274 (char *)&got, sizeof got) 275 != sizeof got) { 276 perror(" DUMP: error reading command pipe in master"); 277 dumpabort(0); 278 } 279 slaves[i].sent = 0; 280 } 281 } 282 283 close_rewind(); 284 rollforward(); 285 return; 286 } 287 } 288 289 blks = 0; 290 if (spcl.c_type != TS_END) { 291 for (i = 0; i < spcl.c_count; i++) 292 if (spcl.c_addr[i] != 0) 293 blks++; 294 } 295 slp->count = lastspclrec + blks + 1 - spcl.c_tapea; 296 slp->tapea = spcl.c_tapea; 297 slp->firstrec = lastfirstrec + ntrec; 298 slp->inode = curino; 299 nextblock = slp->tblock; 300 trecno = 0; 301 asize += tenths; 302 blockswritten += ntrec; 303 blocksthisvol += ntrec; 304 if (!pipeout && (blocksperfile ? 305 (blocksthisvol >= blocksperfile) : (asize > tsize))) { 306 close_rewind(); 307 startnewtape(0); 308 } 309 timeest(); 310 } 311 312 void 313 trewind() 314 { 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 (void) close(tapefd); 360 while ((f = open(tape, 0)) < 0) 361 sleep (10); 362 (void) close(f); 363 } 364 365 void 366 close_rewind() 367 { 368 trewind(); 369 if (nexttape) 370 return; 371 if (!nogripe) { 372 msg("Change Volumes: Mount volume #%d\n", tapeno+1); 373 broadcast("CHANGE DUMP VOLUMES!\7\7\n"); 374 } 375 while (!query("Is the new volume mounted and ready to go?")) 376 if (query("Do you want to abort?")) { 377 dumpabort(0); 378 /*NOTREACHED*/ 379 } 380 } 381 382 void 383 rollforward() 384 { 385 register struct req *p, *q, *prev; 386 register struct slave *tslp; 387 int i, size, savedtapea, got; 388 union u_spcl *ntb, *otb; 389 tslp = &slaves[SLAVES]; 390 ntb = (union u_spcl *)tslp->tblock[1]; 391 392 /* 393 * Each of the N slaves should have requests that need to 394 * be replayed on the next tape. Use the extra slave buffers 395 * (slaves[SLAVES]) to construct request lists to be sent to 396 * each slave in turn. 397 */ 398 for (i = 0; i < SLAVES; i++) { 399 q = &tslp->req[1]; 400 otb = (union u_spcl *)slp->tblock; 401 402 /* 403 * For each request in the current slave, copy it to tslp. 404 */ 405 406 for (p = slp->req; p->count > 0; p += p->count) { 407 *q = *p; 408 if (p->dblk == 0) 409 *ntb++ = *otb++; /* copy the datablock also */ 410 prev = q; 411 q += q->count; 412 } 413 if (prev->dblk != 0) 414 prev->count -= 1; 415 else 416 ntb--; 417 q -= 1; 418 q->count = 0; 419 q = &tslp->req[0]; 420 if (i == 0) { 421 q->dblk = 0; 422 q->count = 1; 423 trecno = 0; 424 nextblock = tslp->tblock; 425 savedtapea = spcl.c_tapea; 426 spcl.c_tapea = slp->tapea; 427 startnewtape(0); 428 spcl.c_tapea = savedtapea; 429 lastspclrec = savedtapea - 1; 430 } 431 size = (char *)ntb - (char *)q; 432 if (atomic(write, slp->fd, (char *)q, size) != size) { 433 perror(" DUMP: error writing command pipe"); 434 dumpabort(0); 435 } 436 slp->sent = 1; 437 if (++slp >= &slaves[SLAVES]) 438 slp = &slaves[0]; 439 440 q->count = 1; 441 442 if (prev->dblk != 0) { 443 /* 444 * If the last one was a disk block, make the 445 * first of this one be the last bit of that disk 446 * block... 447 */ 448 q->dblk = prev->dblk + 449 prev->count * (TP_BSIZE / DEV_BSIZE); 450 ntb = (union u_spcl *)tslp->tblock; 451 } else { 452 /* 453 * It wasn't a disk block. Copy the data to its 454 * new location in the buffer. 455 */ 456 q->dblk = 0; 457 *((union u_spcl *)tslp->tblock) = *ntb; 458 ntb = (union u_spcl *)tslp->tblock[1]; 459 } 460 } 461 slp->req[0] = *q; 462 nextblock = slp->tblock; 463 if (q->dblk == 0) 464 nextblock++; 465 trecno = 1; 466 467 /* 468 * Clear the first slaves' response. One hopes that it 469 * worked ok, otherwise the tape is much too short! 470 */ 471 if (slp->sent) { 472 if (atomic(read, slp->fd, (char *)&got, sizeof got) 473 != sizeof got) { 474 perror(" DUMP: error reading command pipe in master"); 475 dumpabort(0); 476 } 477 slp->sent = 0; 478 479 if (got != writesize) { 480 quit("EOT detected at start of the tape!\n"); 481 } 482 } 483 } 484 485 /* 486 * We implement taking and restoring checkpoints on the tape level. 487 * When each tape is opened, a new process is created by forking; this 488 * saves all of the necessary context in the parent. The child 489 * continues the dump; the parent waits around, saving the context. 490 * If the child returns X_REWRITE, then it had problems writing that tape; 491 * this causes the parent to fork again, duplicating the context, and 492 * everything continues as if nothing had happened. 493 */ 494 void 495 startnewtape(top) 496 int top; 497 { 498 int parentpid; 499 int childpid; 500 int status; 501 int waitpid; 502 char *p; 503 #ifdef sunos 504 void (*interrupt_save)(); 505 char *index(); 506 #else 507 sig_t interrupt_save; 508 #endif 509 510 interrupt_save = signal(SIGINT, SIG_IGN); 511 parentpid = getpid(); 512 513 restore_check_point: 514 (void)signal(SIGINT, interrupt_save); 515 /* 516 * All signals are inherited... 517 */ 518 childpid = fork(); 519 if (childpid < 0) { 520 msg("Context save fork fails in parent %d\n", parentpid); 521 Exit(X_ABORT); 522 } 523 if (childpid != 0) { 524 /* 525 * PARENT: 526 * save the context by waiting 527 * until the child doing all of the work returns. 528 * don't catch the interrupt 529 */ 530 signal(SIGINT, SIG_IGN); 531 #ifdef TDEBUG 532 msg("Tape: %d; parent process: %d child process %d\n", 533 tapeno+1, parentpid, childpid); 534 #endif TDEBUG 535 while ((waitpid = wait(&status)) != childpid) 536 msg("Parent %d waiting for child %d has another child %d return\n", 537 parentpid, childpid, waitpid); 538 if (status & 0xFF) { 539 msg("Child %d returns LOB status %o\n", 540 childpid, status&0xFF); 541 } 542 status = (status >> 8) & 0xFF; 543 #ifdef TDEBUG 544 switch(status) { 545 case X_FINOK: 546 msg("Child %d finishes X_FINOK\n", childpid); 547 break; 548 case X_ABORT: 549 msg("Child %d finishes X_ABORT\n", childpid); 550 break; 551 case X_REWRITE: 552 msg("Child %d finishes X_REWRITE\n", childpid); 553 break; 554 default: 555 msg("Child %d finishes unknown %d\n", 556 childpid, status); 557 break; 558 } 559 #endif TDEBUG 560 switch(status) { 561 case X_FINOK: 562 Exit(X_FINOK); 563 case X_ABORT: 564 Exit(X_ABORT); 565 case X_REWRITE: 566 goto restore_check_point; 567 default: 568 msg("Bad return code from dump: %d\n", status); 569 Exit(X_ABORT); 570 } 571 /*NOTREACHED*/ 572 } else { /* we are the child; just continue */ 573 #ifdef TDEBUG 574 sleep(4); /* allow time for parent's message to get out */ 575 msg("Child on Tape %d has parent %d, my pid = %d\n", 576 tapeno+1, parentpid, getpid()); 577 #endif TDEBUG 578 /* 579 * If we have a name like "/dev/rmt0,/dev/rmt1", 580 * use the name before the comma first, and save 581 * the remaining names for subsequent volumes. 582 */ 583 tapeno++; /* current tape sequence */ 584 if (nexttape || index(tape, ',')) { 585 if (nexttape && *nexttape) 586 tape = nexttape; 587 if (p = index(tape, ',')) { 588 *p = '\0'; 589 nexttape = p + 1; 590 } else 591 nexttape = NULL; 592 msg("Dumping volume %d on %s\n", tapeno, tape); 593 } 594 #ifdef RDUMP 595 while ((tapefd = (host ? rmtopen(tape, 2) : 596 pipeout ? 1 : open(tape, O_WRONLY|O_CREAT, 0666))) < 0) 597 #else 598 while ((tapefd = (pipeout ? 1 : 599 open(tape, O_WRONLY|O_CREAT, 0666))) < 0) 600 #endif 601 { 602 msg("Cannot open output \"%s\".\n", tape); 603 if (!query("Do you want to retry the open?")) 604 dumpabort(0); 605 } 606 607 enslave(); /* Share open tape file descriptor with slaves */ 608 609 asize = 0; 610 blocksthisvol = 0; 611 if (top) 612 newtape++; /* new tape signal */ 613 spcl.c_count = slp->count; 614 /* 615 * measure firstrec in TP_BSIZE units since restore doesn't 616 * know the correct ntrec value... 617 */ 618 spcl.c_firstrec = slp->firstrec; 619 spcl.c_volume++; 620 spcl.c_type = TS_TAPE; 621 spcl.c_flags |= DR_NEWHEADER; 622 writeheader((ino_t)slp->inode); 623 spcl.c_flags &=~ DR_NEWHEADER; 624 if (tapeno > 1) 625 msg("Volume %d begins with blocks from inode %d\n", 626 tapeno, slp->inode); 627 } 628 } 629 630 void 631 dumpabort(signo) 632 int signo; 633 { 634 635 if (master != 0 && master != getpid()) 636 /* Signals master to call dumpabort */ 637 (void) kill(master, SIGTERM); 638 else { 639 killall(); 640 msg("The ENTIRE dump is aborted.\n"); 641 } 642 #ifdef RDUMP 643 rmtclose(); 644 #endif 645 Exit(X_ABORT); 646 } 647 648 void 649 Exit(status) 650 int status; 651 { 652 653 #ifdef TDEBUG 654 msg("pid = %d exits with status %d\n", getpid(), status); 655 #endif TDEBUG 656 (void) exit(status); 657 } 658 659 /* 660 * proceed - handler for SIGUSR2, used to synchronize IO between the slaves. 661 */ 662 void 663 proceed(signo) 664 int signo; 665 { 666 667 if (ready) 668 longjmp(jmpbuf, 1); 669 caught++; 670 } 671 672 void 673 enslave() 674 { 675 int cmd[2]; 676 register int i, j; 677 678 master = getpid(); 679 680 signal(SIGTERM, dumpabort); /* Slave sends SIGTERM on dumpabort() */ 681 signal(SIGPIPE, sigpipe); 682 signal(SIGUSR1, tperror); /* Slave sends SIGUSR1 on tape errors */ 683 signal(SIGUSR2, proceed); /* Slave sends SIGUSR2 to next slave */ 684 685 for (i = 0; i < SLAVES; i++) { 686 if (i == slp - &slaves[0]) { 687 caught = 1; 688 } else { 689 caught = 0; 690 } 691 692 if (socketpair(AF_UNIX, SOCK_STREAM, 0, cmd) < 0 || 693 (slaves[i].pid = fork()) < 0) 694 quit("too many slaves, %d (recompile smaller): %s\n", 695 i, strerror(errno)); 696 697 slaves[i].fd = cmd[1]; 698 slaves[i].sent = 0; 699 if (slaves[i].pid == 0) { /* Slave starts up here */ 700 for (j = 0; j <= i; j++) 701 (void) close(slaves[j].fd); 702 signal(SIGINT, SIG_IGN); /* Master handles this */ 703 doslave(cmd[0], i); 704 Exit(X_FINOK); 705 } 706 } 707 708 for (i = 0; i < SLAVES; i++) 709 (void) atomic(write, slaves[i].fd, 710 (char *) &slaves[(i + 1) % SLAVES].pid, 711 sizeof slaves[0].pid); 712 713 master = 0; 714 } 715 716 void 717 killall() 718 { 719 register int i; 720 721 for (i = 0; i < SLAVES; i++) 722 if (slaves[i].pid > 0) 723 (void) kill(slaves[i].pid, SIGKILL); 724 } 725 726 /* 727 * Synchronization - each process has a lockfile, and shares file 728 * descriptors to the following process's lockfile. When our write 729 * completes, we release our lock on the following process's lock- 730 * file, allowing the following process to lock it and proceed. We 731 * get the lock back for the next cycle by swapping descriptors. 732 */ 733 void 734 doslave(cmd, slave_number) 735 register int cmd; 736 int slave_number; 737 { 738 register int nread; 739 int nextslave, size, wrote, eot_count; 740 #ifndef __STDC__ 741 int read(); 742 #endif 743 744 /* 745 * Need our own seek pointer. 746 */ 747 (void) close(diskfd); 748 if ((diskfd = open(disk, O_RDONLY)) < 0) 749 quit("slave couldn't reopen disk: %s\n", strerror(errno)); 750 751 /* 752 * Need the pid of the next slave in the loop... 753 */ 754 if ((nread = atomic(read, cmd, (char *)&nextslave, sizeof nextslave)) 755 != sizeof nextslave) { 756 quit("master/slave protocol botched - didn't get pid of next slave.\n"); 757 } 758 759 /* 760 * Get list of blocks to dump, read the blocks into tape buffer 761 */ 762 while ((nread = atomic(read, cmd, (char *)slp->req, reqsiz)) == reqsiz) { 763 register struct req *p = slp->req; 764 765 for (trecno = 0; trecno < ntrec; 766 trecno += p->count, p += p->count) { 767 if (p->dblk) { 768 bread(p->dblk, slp->tblock[trecno], 769 p->count * TP_BSIZE); 770 } else { 771 if (p->count != 1 || atomic(read, cmd, 772 (char *)slp->tblock[trecno], 773 TP_BSIZE) != TP_BSIZE) 774 quit("master/slave protocol botched.\n"); 775 } 776 } 777 if (setjmp(jmpbuf) == 0) { 778 ready = 1; 779 if (!caught) 780 (void) pause(); 781 } 782 ready = 0; 783 caught = 0; 784 785 /* Try to write the data... */ 786 eot_count = 0; 787 size = 0; 788 789 while (eot_count < 10 && size < writesize) { 790 #ifdef RDUMP 791 if (host) 792 wrote = rmtwrite(slp->tblock[0]+size, 793 writesize-size); 794 else 795 #endif 796 wrote = write(tapefd, slp->tblock[0]+size, 797 writesize-size); 798 #ifdef WRITEDEBUG 799 printf("slave %d wrote %d\n", slave_number, wrote); 800 #endif 801 if (wrote < 0) 802 break; 803 if (wrote == 0) 804 eot_count++; 805 size += wrote; 806 } 807 808 #ifdef WRITEDEBUG 809 if (size != writesize) 810 printf("slave %d only wrote %d out of %d bytes and gave up.\n", 811 slave_number, size, writesize); 812 #endif 813 814 if (eot_count > 0) 815 size = 0; 816 817 /* 818 * fixme: Pyramids running OSx return ENOSPC 819 * at EOT on 1/2 inch drives. 820 */ 821 if (size < 0) { 822 (void) kill(master, SIGUSR1); 823 for (;;) 824 (void) sigpause(0); 825 } else { 826 /* 827 * pass size of write back to master 828 * (for EOT handling) 829 */ 830 (void) atomic(write, cmd, (char *)&size, sizeof size); 831 } 832 833 /* 834 * If partial write, don't want next slave to go. 835 * Also jolts him awake. 836 */ 837 (void) kill(nextslave, SIGUSR2); 838 } 839 if (nread != 0) 840 quit("error reading command pipe: %s\n", strerror(errno)); 841 } 842 843 /* 844 * Since a read from a pipe may not return all we asked for, 845 * or a write may not write all we ask if we get a signal, 846 * loop until the count is satisfied (or error). 847 */ 848 int 849 atomic(func, fd, buf, count) 850 int (*func)(), fd, count; 851 char *buf; 852 { 853 int got, need = count; 854 855 while ((got = (*func)(fd, buf, need)) > 0 && (need -= got) > 0) 856 buf += got; 857 return (got < 0 ? got : count - need); 858 } 859
Indexes created Mon Sep 22 10:09:38 GMT 2025