tape.c revision 1.4
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 34 #ifndef lint 35 /*static char sccsid[] = "from: @(#)tape.c 8.2 (Berkeley) 3/17/94";*/ 36 static char *rcsid = "$Id: tape.c,v 1.4 1994/09/23 14:27:06 mycroft Exp $"; 37 #endif /* not lint */ 38 39 #include <sys/param.h> 40 #include <sys/socket.h> 41 #include <sys/time.h> 42 #include <sys/wait.h> 43 #ifdef sunos 44 #include <sys/vnode.h> 45 46 #include <ufs/fs.h> 47 #include <ufs/inode.h> 48 #else 49 #include <ufs/ffs/fs.h> 50 #include <ufs/ufs/dinode.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 #include "pathnames.h" 70 71 int writesize; /* size of malloc()ed buffer for tape */ 72 long lastspclrec = -1; /* tape block number of last written header */ 73 int trecno = 0; /* next record to write in current block */ 74 extern long blocksperfile; /* number of blocks per output file */ 75 long blocksthisvol; /* number of blocks on current output file */ 76 extern int ntrec; /* blocking factor on tape */ 77 extern int cartridge; 78 extern char *host; 79 char *nexttape; 80 81 static int atomic __P((int (*)(), int, char *, int)); 82 static void doslave __P((int, int)); 83 static void enslave __P((void)); 84 static void flushtape __P((void)); 85 static void killall __P((void)); 86 static void rollforward __P((void)); 87 88 /* 89 * Concurrent dump mods (Caltech) - disk block reading and tape writing 90 * are exported to several slave processes. While one slave writes the 91 * tape, the others read disk blocks; they pass control of the tape in 92 * a ring via signals. The parent process traverses the filesystem and 93 * sends writeheader()'s and lists of daddr's to the slaves via pipes. 94 * The following structure defines the instruction packets sent to slaves. 95 */ 96 struct req { 97 daddr_t dblk; 98 int count; 99 }; 100 int reqsiz; 101 102 #define SLAVES 3 /* 1 slave writing, 1 reading, 1 for slack */ 103 struct slave { 104 int tapea; /* header number at start of this chunk */ 105 int count; /* count to next header (used for TS_TAPE */ 106 /* after EOT) */ 107 int inode; /* inode that we are currently dealing with */ 108 int fd; /* FD for this slave */ 109 int pid; /* PID for this slave */ 110 int sent; /* 1 == we've sent this slave requests */ 111 int firstrec; /* record number of this block */ 112 char (*tblock)[TP_BSIZE]; /* buffer for data blocks */ 113 struct req *req; /* buffer for requests */ 114 } slaves[SLAVES+1]; 115 struct slave *slp; 116 117 char (*nextblock)[TP_BSIZE]; 118 119 int master; /* pid of master, for sending error signals */ 120 int tenths; /* length of tape used per block written */ 121 static int caught; /* have we caught the signal to proceed? */ 122 static int ready; /* have we reached the lock point without having */ 123 /* received the SIGUSR2 signal from the prev slave? */ 124 static jmp_buf jmpbuf; /* where to jump to if we are ready when the */ 125 /* SIGUSR2 arrives from the previous slave */ 126 127 int 128 alloctape() 129 { 130 int pgoff = getpagesize() - 1; 131 char *buf; 132 int i; 133 134 writesize = ntrec * TP_BSIZE; 135 reqsiz = (ntrec + 1) * sizeof(struct req); 136 /* 137 * CDC 92181's and 92185's make 0.8" gaps in 1600-bpi start/stop mode 138 * (see DEC TU80 User's Guide). The shorter gaps of 6250-bpi require 139 * repositioning after stopping, i.e, streaming mode, where the gap is 140 * variable, 0.30" to 0.45". The gap is maximal when the tape stops. 141 */ 142 if (blocksperfile == 0) 143 tenths = writesize / density + 144 (cartridge ? 16 : density == 625 ? 5 : 8); 145 /* 146 * Allocate tape buffer contiguous with the array of instruction 147 * packets, so flushtape() can write them together with one write(). 148 * Align tape buffer on page boundary to speed up tape write(). 149 */ 150 for (i = 0; i <= SLAVES; i++) { 151 buf = (char *) 152 malloc((unsigned)(reqsiz + writesize + pgoff + TP_BSIZE)); 153 if (buf == NULL) 154 return(0); 155 slaves[i].tblock = (char (*)[TP_BSIZE]) 156 (((long)&buf[ntrec + 1] + pgoff) &~ pgoff); 157 slaves[i].req = (struct req *)slaves[i].tblock - ntrec - 1; 158 } 159 slp = &slaves[0]; 160 slp->count = 1; 161 slp->tapea = 0; 162 slp->firstrec = 0; 163 nextblock = slp->tblock; 164 return(1); 165 } 166 167 void 168 writerec(dp, isspcl) 169 char *dp; 170 int isspcl; 171 { 172 173 slp->req[trecno].dblk = (daddr_t)0; 174 slp->req[trecno].count = 1; 175 *(union u_spcl *)(*(nextblock)++) = *(union u_spcl *)dp; 176 if (isspcl) 177 lastspclrec = spcl.c_tapea; 178 trecno++; 179 spcl.c_tapea++; 180 if (trecno >= ntrec) 181 flushtape(); 182 } 183 184 void 185 dumpblock(blkno, size) 186 daddr_t blkno; 187 int size; 188 { 189 int avail, tpblks, dblkno; 190 191 dblkno = fsbtodb(sblock, blkno); 192 tpblks = size >> tp_bshift; 193 while ((avail = MIN(tpblks, ntrec - trecno)) > 0) { 194 slp->req[trecno].dblk = dblkno; 195 slp->req[trecno].count = avail; 196 trecno += avail; 197 spcl.c_tapea += avail; 198 if (trecno >= ntrec) 199 flushtape(); 200 dblkno += avail << (tp_bshift - dev_bshift); 201 tpblks -= avail; 202 } 203 } 204 205 int nogripe = 0; 206 207 void 208 tperror(signo) 209 int signo; 210 { 211 212 if (pipeout) { 213 msg("write error on %s\n", tape); 214 quit("Cannot recover\n"); 215 /* NOTREACHED */ 216 } 217 msg("write error %d blocks into volume %d\n", blocksthisvol, tapeno); 218 broadcast("DUMP WRITE ERROR!\n"); 219 if (!query("Do you want to restart?")) 220 dumpabort(0); 221 msg("Closing this volume. Prepare to restart with new media;\n"); 222 msg("this dump volume will be rewritten.\n"); 223 killall(); 224 nogripe = 1; 225 close_rewind(); 226 Exit(X_REWRITE); 227 } 228 229 void 230 sigpipe(signo) 231 int signo; 232 { 233 234 quit("Broken pipe\n"); 235 } 236 237 static void 238 flushtape() 239 { 240 int i, blks, got; 241 long lastfirstrec; 242 243 int siz = (char *)nextblock - (char *)slp->req; 244 245 slp->req[trecno].count = 0; /* Sentinel */ 246 247 if (atomic(write, slp->fd, (char *)slp->req, siz) != siz) 248 quit("error writing command pipe: %s\n", strerror(errno)); 249 slp->sent = 1; /* we sent a request, read the response later */ 250 251 lastfirstrec = slp->firstrec; 252 253 if (++slp >= &slaves[SLAVES]) 254 slp = &slaves[0]; 255 256 /* Read results back from next slave */ 257 if (slp->sent) { 258 if (atomic(read, slp->fd, (char *)&got, sizeof got) 259 != sizeof got) { 260 perror(" DUMP: error reading command pipe in master"); 261 dumpabort(0); 262 } 263 slp->sent = 0; 264 265 /* Check for end of tape */ 266 if (got < writesize) { 267 msg("End of tape detected\n"); 268 269 /* 270 * Drain the results, don't care what the values were. 271 * If we read them here then trewind won't... 272 */ 273 for (i = 0; i < SLAVES; i++) { 274 if (slaves[i].sent) { 275 if (atomic(read, slaves[i].fd, 276 (char *)&got, sizeof got) 277 != sizeof got) { 278 perror(" DUMP: error reading command pipe in master"); 279 dumpabort(0); 280 } 281 slaves[i].sent = 0; 282 } 283 } 284 285 close_rewind(); 286 rollforward(); 287 return; 288 } 289 } 290 291 blks = 0; 292 if (spcl.c_type != TS_END) { 293 for (i = 0; i < spcl.c_count; i++) 294 if (spcl.c_addr[i] != 0) 295 blks++; 296 } 297 slp->count = lastspclrec + blks + 1 - spcl.c_tapea; 298 slp->tapea = spcl.c_tapea; 299 slp->firstrec = lastfirstrec + ntrec; 300 slp->inode = curino; 301 nextblock = slp->tblock; 302 trecno = 0; 303 asize += tenths; 304 blockswritten += ntrec; 305 blocksthisvol += ntrec; 306 if (!pipeout && (blocksperfile ? 307 (blocksthisvol >= blocksperfile) : (asize > tsize))) { 308 close_rewind(); 309 startnewtape(0); 310 } 311 timeest(); 312 } 313 314 void 315 trewind() 316 { 317 int f; 318 int got; 319 320 for (f = 0; f < SLAVES; f++) { 321 /* 322 * Drain the results, but unlike EOT we DO (or should) care 323 * what the return values were, since if we detect EOT after 324 * we think we've written the last blocks to the tape anyway, 325 * we have to replay those blocks with rollforward. 326 * 327 * fixme: punt for now. 328 */ 329 if (slaves[f].sent) { 330 if (atomic(read, slaves[f].fd, (char *)&got, sizeof got) 331 != sizeof got) { 332 perror(" DUMP: error reading command pipe in master"); 333 dumpabort(0); 334 } 335 slaves[f].sent = 0; 336 if (got != writesize) { 337 msg("EOT detected in last 2 tape records!\n"); 338 msg("Use a longer tape, decrease the size estimate\n"); 339 quit("or use no size estimate at all.\n"); 340 } 341 } 342 (void) close(slaves[f].fd); 343 } 344 while (wait((int *)NULL) >= 0) /* wait for any signals from slaves */ 345 /* void */; 346 347 if (pipeout) 348 return; 349 350 msg("Closing %s\n", tape); 351 352 #ifdef RDUMP 353 if (host) { 354 rmtclose(); 355 while (rmtopen(tape, 0) < 0) 356 sleep(10); 357 rmtclose(); 358 return; 359 } 360 #endif 361 (void) close(tapefd); 362 while ((f = open(tape, 0)) < 0) 363 sleep (10); 364 (void) close(f); 365 } 366 367 void 368 close_rewind() 369 { 370 trewind(); 371 if (nexttape) 372 return; 373 if (!nogripe) { 374 msg("Change Volumes: Mount volume #%d\n", tapeno+1); 375 broadcast("CHANGE DUMP VOLUMES!\7\7\n"); 376 } 377 while (!query("Is the new volume mounted and ready to go?")) 378 if (query("Do you want to abort?")) { 379 dumpabort(0); 380 /*NOTREACHED*/ 381 } 382 } 383 384 void 385 rollforward() 386 { 387 register struct req *p, *q, *prev; 388 register struct slave *tslp; 389 int i, size, savedtapea, got; 390 union u_spcl *ntb, *otb; 391 tslp = &slaves[SLAVES]; 392 ntb = (union u_spcl *)tslp->tblock[1]; 393 394 /* 395 * Each of the N slaves should have requests that need to 396 * be replayed on the next tape. Use the extra slave buffers 397 * (slaves[SLAVES]) to construct request lists to be sent to 398 * each slave in turn. 399 */ 400 for (i = 0; i < SLAVES; i++) { 401 q = &tslp->req[1]; 402 otb = (union u_spcl *)slp->tblock; 403 404 /* 405 * For each request in the current slave, copy it to tslp. 406 */ 407 408 prev = NULL; 409 for (p = slp->req; p->count > 0; p += p->count) { 410 *q = *p; 411 if (p->dblk == 0) 412 *ntb++ = *otb++; /* copy the datablock also */ 413 prev = q; 414 q += q->count; 415 } 416 if (prev == NULL) 417 quit("rollforward: protocol botch"); 418 if (prev->dblk != 0) 419 prev->count -= 1; 420 else 421 ntb--; 422 q -= 1; 423 q->count = 0; 424 q = &tslp->req[0]; 425 if (i == 0) { 426 q->dblk = 0; 427 q->count = 1; 428 trecno = 0; 429 nextblock = tslp->tblock; 430 savedtapea = spcl.c_tapea; 431 spcl.c_tapea = slp->tapea; 432 startnewtape(0); 433 spcl.c_tapea = savedtapea; 434 lastspclrec = savedtapea - 1; 435 } 436 size = (char *)ntb - (char *)q; 437 if (atomic(write, slp->fd, (char *)q, size) != size) { 438 perror(" DUMP: error writing command pipe"); 439 dumpabort(0); 440 } 441 slp->sent = 1; 442 if (++slp >= &slaves[SLAVES]) 443 slp = &slaves[0]; 444 445 q->count = 1; 446 447 if (prev->dblk != 0) { 448 /* 449 * If the last one was a disk block, make the 450 * first of this one be the last bit of that disk 451 * block... 452 */ 453 q->dblk = prev->dblk + 454 prev->count * (TP_BSIZE / DEV_BSIZE); 455 ntb = (union u_spcl *)tslp->tblock; 456 } else { 457 /* 458 * It wasn't a disk block. Copy the data to its 459 * new location in the buffer. 460 */ 461 q->dblk = 0; 462 *((union u_spcl *)tslp->tblock) = *ntb; 463 ntb = (union u_spcl *)tslp->tblock[1]; 464 } 465 } 466 slp->req[0] = *q; 467 nextblock = slp->tblock; 468 if (q->dblk == 0) 469 nextblock++; 470 trecno = 1; 471 472 /* 473 * Clear the first slaves' response. One hopes that it 474 * worked ok, otherwise the tape is much too short! 475 */ 476 if (slp->sent) { 477 if (atomic(read, slp->fd, (char *)&got, sizeof got) 478 != sizeof got) { 479 perror(" DUMP: error reading command pipe in master"); 480 dumpabort(0); 481 } 482 slp->sent = 0; 483 484 if (got != writesize) { 485 quit("EOT detected at start of the tape!\n"); 486 } 487 } 488 } 489 490 /* 491 * We implement taking and restoring checkpoints on the tape level. 492 * When each tape is opened, a new process is created by forking; this 493 * saves all of the necessary context in the parent. The child 494 * continues the dump; the parent waits around, saving the context. 495 * If the child returns X_REWRITE, then it had problems writing that tape; 496 * this causes the parent to fork again, duplicating the context, and 497 * everything continues as if nothing had happened. 498 */ 499 void 500 startnewtape(top) 501 int top; 502 { 503 int parentpid; 504 int childpid; 505 int status; 506 int waitpid; 507 char *p; 508 #ifdef sunos 509 void (*interrupt_save)(); 510 #else 511 sig_t interrupt_save; 512 #endif 513 514 interrupt_save = signal(SIGINT, SIG_IGN); 515 parentpid = getpid(); 516 517 restore_check_point: 518 (void)signal(SIGINT, interrupt_save); 519 /* 520 * All signals are inherited... 521 */ 522 childpid = fork(); 523 if (childpid < 0) { 524 msg("Context save fork fails in parent %d\n", parentpid); 525 Exit(X_ABORT); 526 } 527 if (childpid != 0) { 528 /* 529 * PARENT: 530 * save the context by waiting 531 * until the child doing all of the work returns. 532 * don't catch the interrupt 533 */ 534 signal(SIGINT, SIG_IGN); 535 #ifdef TDEBUG 536 msg("Tape: %d; parent process: %d child process %d\n", 537 tapeno+1, parentpid, childpid); 538 #endif /* TDEBUG */ 539 while ((waitpid = wait(&status)) != childpid) 540 msg("Parent %d waiting for child %d has another child %d return\n", 541 parentpid, childpid, waitpid); 542 if (status & 0xFF) { 543 msg("Child %d returns LOB status %o\n", 544 childpid, status&0xFF); 545 } 546 status = (status >> 8) & 0xFF; 547 #ifdef TDEBUG 548 switch(status) { 549 case X_FINOK: 550 msg("Child %d finishes X_FINOK\n", childpid); 551 break; 552 case X_ABORT: 553 msg("Child %d finishes X_ABORT\n", childpid); 554 break; 555 case X_REWRITE: 556 msg("Child %d finishes X_REWRITE\n", childpid); 557 break; 558 default: 559 msg("Child %d finishes unknown %d\n", 560 childpid, status); 561 break; 562 } 563 #endif /* TDEBUG */ 564 switch(status) { 565 case X_FINOK: 566 Exit(X_FINOK); 567 case X_ABORT: 568 Exit(X_ABORT); 569 case X_REWRITE: 570 goto restore_check_point; 571 default: 572 msg("Bad return code from dump: %d\n", status); 573 Exit(X_ABORT); 574 } 575 /*NOTREACHED*/ 576 } else { /* we are the child; just continue */ 577 #ifdef TDEBUG 578 sleep(4); /* allow time for parent's message to get out */ 579 msg("Child on Tape %d has parent %d, my pid = %d\n", 580 tapeno+1, parentpid, getpid()); 581 #endif /* TDEBUG */ 582 /* 583 * If we have a name like "/dev/rmt0,/dev/rmt1", 584 * use the name before the comma first, and save 585 * the remaining names for subsequent volumes. 586 */ 587 tapeno++; /* current tape sequence */ 588 if (nexttape || strchr(tape, ',')) { 589 if (nexttape && *nexttape) 590 tape = nexttape; 591 if ((p = strchr(tape, ',')) != NULL) { 592 *p = '\0'; 593 nexttape = p + 1; 594 } else 595 nexttape = NULL; 596 msg("Dumping volume %d on %s\n", tapeno, tape); 597 } 598 #ifdef RDUMP 599 while ((tapefd = (host ? rmtopen(tape, 2) : 600 pipeout ? 1 : open(tape, O_WRONLY|O_CREAT, 0666))) < 0) 601 #else 602 while ((tapefd = (pipeout ? 1 : 603 open(tape, O_WRONLY|O_CREAT, 0666))) < 0) 604 #endif 605 { 606 msg("Cannot open output \"%s\".\n", tape); 607 if (!query("Do you want to retry the open?")) 608 dumpabort(0); 609 } 610 611 enslave(); /* Share open tape file descriptor with slaves */ 612 613 asize = 0; 614 blocksthisvol = 0; 615 if (top) 616 newtape++; /* new tape signal */ 617 spcl.c_count = slp->count; 618 /* 619 * measure firstrec in TP_BSIZE units since restore doesn't 620 * know the correct ntrec value... 621 */ 622 spcl.c_firstrec = slp->firstrec; 623 spcl.c_volume++; 624 spcl.c_type = TS_TAPE; 625 spcl.c_flags |= DR_NEWHEADER; 626 writeheader((ino_t)slp->inode); 627 spcl.c_flags &=~ DR_NEWHEADER; 628 if (tapeno > 1) 629 msg("Volume %d begins with blocks from inode %d\n", 630 tapeno, slp->inode); 631 } 632 } 633 634 void 635 dumpabort(signo) 636 int signo; 637 { 638 639 if (master != 0 && master != getpid()) 640 /* Signals master to call dumpabort */ 641 (void) kill(master, SIGTERM); 642 else { 643 killall(); 644 msg("The ENTIRE dump is aborted.\n"); 645 } 646 #ifdef RDUMP 647 rmtclose(); 648 #endif 649 Exit(X_ABORT); 650 } 651 652 __dead void 653 Exit(status) 654 int status; 655 { 656 657 #ifdef TDEBUG 658 msg("pid = %d exits with status %d\n", getpid(), status); 659 #endif /* TDEBUG */ 660 exit(status); 661 } 662 663 /* 664 * proceed - handler for SIGUSR2, used to synchronize IO between the slaves. 665 */ 666 void 667 proceed(signo) 668 int signo; 669 { 670 671 if (ready) 672 longjmp(jmpbuf, 1); 673 caught++; 674 } 675 676 void 677 enslave() 678 { 679 int cmd[2]; 680 register int i, j; 681 682 master = getpid(); 683 684 signal(SIGTERM, dumpabort); /* Slave sends SIGTERM on dumpabort() */ 685 signal(SIGPIPE, sigpipe); 686 signal(SIGUSR1, tperror); /* Slave sends SIGUSR1 on tape errors */ 687 signal(SIGUSR2, proceed); /* Slave sends SIGUSR2 to next slave */ 688 689 for (i = 0; i < SLAVES; i++) { 690 if (i == slp - &slaves[0]) { 691 caught = 1; 692 } else { 693 caught = 0; 694 } 695 696 if (socketpair(AF_UNIX, SOCK_STREAM, 0, cmd) < 0 || 697 (slaves[i].pid = fork()) < 0) 698 quit("too many slaves, %d (recompile smaller): %s\n", 699 i, strerror(errno)); 700 701 slaves[i].fd = cmd[1]; 702 slaves[i].sent = 0; 703 if (slaves[i].pid == 0) { /* Slave starts up here */ 704 for (j = 0; j <= i; j++) 705 (void) close(slaves[j].fd); 706 signal(SIGINT, SIG_IGN); /* Master handles this */ 707 doslave(cmd[0], i); 708 Exit(X_FINOK); 709 } 710 } 711 712 for (i = 0; i < SLAVES; i++) 713 (void) atomic(write, slaves[i].fd, 714 (char *) &slaves[(i + 1) % SLAVES].pid, 715 sizeof slaves[0].pid); 716 717 master = 0; 718 } 719 720 void 721 killall() 722 { 723 register int i; 724 725 for (i = 0; i < SLAVES; i++) 726 if (slaves[i].pid > 0) 727 (void) kill(slaves[i].pid, SIGKILL); 728 } 729 730 /* 731 * Synchronization - each process has a lockfile, and shares file 732 * descriptors to the following process's lockfile. When our write 733 * completes, we release our lock on the following process's lock- 734 * file, allowing the following process to lock it and proceed. We 735 * get the lock back for the next cycle by swapping descriptors. 736 */ 737 static void 738 doslave(cmd, slave_number) 739 register int cmd; 740 int slave_number; 741 { 742 register int nread; 743 int nextslave, size, wrote, eot_count; 744 745 /* 746 * Need our own seek pointer. 747 */ 748 (void) close(diskfd); 749 if ((diskfd = open(disk, O_RDONLY)) < 0) 750 quit("slave couldn't reopen disk: %s\n", strerror(errno)); 751 752 /* 753 * Need the pid of the next slave in the loop... 754 */ 755 if ((nread = atomic(read, cmd, (char *)&nextslave, sizeof nextslave)) 756 != sizeof nextslave) { 757 quit("master/slave protocol botched - didn't get pid of next slave.\n"); 758 } 759 760 /* 761 * Get list of blocks to dump, read the blocks into tape buffer 762 */ 763 while ((nread = atomic(read, cmd, (char *)slp->req, reqsiz)) == reqsiz) { 764 register struct req *p = slp->req; 765 766 for (trecno = 0; trecno < ntrec; 767 trecno += p->count, p += p->count) { 768 if (p->dblk) { 769 bread(p->dblk, slp->tblock[trecno], 770 p->count * TP_BSIZE); 771 } else { 772 if (p->count != 1 || atomic(read, cmd, 773 (char *)slp->tblock[trecno], 774 TP_BSIZE) != TP_BSIZE) 775 quit("master/slave protocol botched.\n"); 776 } 777 } 778 if (setjmp(jmpbuf) == 0) { 779 ready = 1; 780 if (!caught) 781 (void) pause(); 782 } 783 ready = 0; 784 caught = 0; 785 786 /* Try to write the data... */ 787 eot_count = 0; 788 size = 0; 789 790 while (eot_count < 10 && size < writesize) { 791 #ifdef RDUMP 792 if (host) 793 wrote = rmtwrite(slp->tblock[0]+size, 794 writesize-size); 795 else 796 #endif 797 wrote = write(tapefd, slp->tblock[0]+size, 798 writesize-size); 799 #ifdef WRITEDEBUG 800 printf("slave %d wrote %d\n", slave_number, wrote); 801 #endif 802 if (wrote < 0) 803 break; 804 if (wrote == 0) 805 eot_count++; 806 size += wrote; 807 } 808 809 #ifdef WRITEDEBUG 810 if (size != writesize) 811 printf("slave %d only wrote %d out of %d bytes and gave up.\n", 812 slave_number, size, writesize); 813 #endif 814 815 if (eot_count > 0) 816 size = 0; 817 818 /* 819 * fixme: Pyramids running OSx return ENOSPC 820 * at EOT on 1/2 inch drives. 821 */ 822 if (size < 0) { 823 (void) kill(master, SIGUSR1); 824 for (;;) 825 (void) sigpause(0); 826 } else { 827 /* 828 * pass size of write back to master 829 * (for EOT handling) 830 */ 831 (void) atomic(write, cmd, (char *)&size, sizeof size); 832 } 833 834 /* 835 * If partial write, don't want next slave to go. 836 * Also jolts him awake. 837 */ 838 (void) kill(nextslave, SIGUSR2); 839 } 840 if (nread != 0) 841 quit("error reading command pipe: %s\n", strerror(errno)); 842 } 843 844 /* 845 * Since a read from a pipe may not return all we asked for, 846 * or a write may not write all we ask if we get a signal, 847 * loop until the count is satisfied (or error). 848 */ 849 static int 850 atomic(func, fd, buf, count) 851 int (*func)(), fd; 852 char *buf; 853 int count; 854 { 855 int got, need = count; 856 857 while ((got = (*func)(fd, buf, need)) > 0 && (need -= got) > 0) 858 buf += got; 859 return (got < 0 ? got : count - need); 860 } 861
Indexes created Tue Sep 23 23:09:58 GMT 2025