1 /* $NetBSD: tape.c,v 1.7 1995/03/21 18:48:47 mycroft Exp $ */ 2 3 /*- 4 * Copyright (c) 1980, 1991, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the University of 18 * California, Berkeley and its contributors. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 #ifndef lint 37 #if 0 38 static char sccsid[] = "@(#)tape.c 8.2 (Berkeley) 3/17/94"; 39 #else 40 static char rcsid[] = "$NetBSD: tape.c,v 1.7 1995/03/21 18:48:47 mycroft Exp $"; 41 #endif 42 #endif /* not lint */ 43 44 #include <sys/param.h> 45 #include <sys/socket.h> 46 #include <sys/time.h> 47 #include <sys/wait.h> 48 #ifdef sunos 49 #include <sys/vnode.h> 50 51 #include <ufs/fs.h> 52 #include <ufs/inode.h> 53 #else 54 #include <ufs/ffs/fs.h> 55 #include <ufs/ufs/dinode.h> 56 #endif 57 58 #include <protocols/dumprestore.h> 59 60 #include <errno.h> 61 #include <fcntl.h> 62 #include <setjmp.h> 63 #include <signal.h> 64 #include <stdio.h> 65 #ifdef __STDC__ 66 #include <stdlib.h> 67 #include <string.h> 68 #include <unistd.h> 69 #else 70 int write(), read(); 71 #endif 72 73 #include "dump.h" 74 #include "pathnames.h" 75 76 int writesize; /* size of malloc()ed buffer for tape */ 77 long lastspclrec = -1; /* tape block number of last written header */ 78 int trecno = 0; /* next record to write in current block */ 79 extern long blocksperfile; /* number of blocks per output file */ 80 long blocksthisvol; /* number of blocks on current output file */ 81 extern int ntrec; /* blocking factor on tape */ 82 extern int cartridge; 83 extern char *host; 84 char *nexttape; 85 86 static ssize_t atomic __P((ssize_t (*)(), int, char *, int)); 87 static void doslave __P((int, int)); 88 static void enslave __P((void)); 89 static void flushtape __P((void)); 90 static void killall __P((void)); 91 static void rollforward __P((void)); 92 93 /* 94 * Concurrent dump mods (Caltech) - disk block reading and tape writing 95 * are exported to several slave processes. While one slave writes the 96 * tape, the others read disk blocks; they pass control of the tape in 97 * a ring via signals. The parent process traverses the filesystem and 98 * sends writeheader()'s and lists of daddr's to the slaves via pipes. 99 * The following structure defines the instruction packets sent to slaves. 100 */ 101 struct req { 102 daddr_t dblk; 103 int count; 104 }; 105 int reqsiz; 106 107 #define SLAVES 3 /* 1 slave writing, 1 reading, 1 for slack */ 108 struct slave { 109 int tapea; /* header number at start of this chunk */ 110 int count; /* count to next header (used for TS_TAPE */ 111 /* after EOT) */ 112 int inode; /* inode that we are currently dealing with */ 113 int fd; /* FD for this slave */ 114 int pid; /* PID for this slave */ 115 int sent; /* 1 == we've sent this slave requests */ 116 int firstrec; /* record number of this block */ 117 char (*tblock)[TP_BSIZE]; /* buffer for data blocks */ 118 struct req *req; /* buffer for requests */ 119 } slaves[SLAVES+1]; 120 struct slave *slp; 121 122 char (*nextblock)[TP_BSIZE]; 123 124 int master; /* pid of master, for sending error signals */ 125 int tenths; /* length of tape used per block written */ 126 static int caught; /* have we caught the signal to proceed? */ 127 static int ready; /* have we reached the lock point without having */ 128 /* received the SIGUSR2 signal from the prev slave? */ 129 static jmp_buf jmpbuf; /* where to jump to if we are ready when the */ 130 /* SIGUSR2 arrives from the previous slave */ 131 132 int 133 alloctape() 134 { 135 int pgoff = getpagesize() - 1; 136 char *buf; 137 int i; 138 139 writesize = ntrec * TP_BSIZE; 140 reqsiz = (ntrec + 1) * sizeof(struct req); 141 /* 142 * CDC 92181's and 92185's make 0.8" gaps in 1600-bpi start/stop mode 143 * (see DEC TU80 User's Guide). The shorter gaps of 6250-bpi require 144 * repositioning after stopping, i.e, streaming mode, where the gap is 145 * variable, 0.30" to 0.45". The gap is maximal when the tape stops. 146 */ 147 if (blocksperfile == 0) 148 tenths = writesize / density + 149 (cartridge ? 16 : density == 625 ? 5 : 8); 150 /* 151 * Allocate tape buffer contiguous with the array of instruction 152 * packets, so flushtape() can write them together with one write(). 153 * Align tape buffer on page boundary to speed up tape write(). 154 */ 155 for (i = 0; i <= SLAVES; i++) { 156 buf = (char *) 157 malloc((unsigned)(reqsiz + writesize + pgoff + TP_BSIZE)); 158 if (buf == NULL) 159 return(0); 160 slaves[i].tblock = (char (*)[TP_BSIZE]) 161 (((long)&buf[ntrec + 1] + pgoff) &~ pgoff); 162 slaves[i].req = (struct req *)slaves[i].tblock - ntrec - 1; 163 } 164 slp = &slaves[0]; 165 slp->count = 1; 166 slp->tapea = 0; 167 slp->firstrec = 0; 168 nextblock = slp->tblock; 169 return(1); 170 } 171 172 void 173 writerec(dp, isspcl) 174 char *dp; 175 int isspcl; 176 { 177 178 slp->req[trecno].dblk = (daddr_t)0; 179 slp->req[trecno].count = 1; 180 *(union u_spcl *)(*(nextblock)++) = *(union u_spcl *)dp; 181 if (isspcl) 182 lastspclrec = spcl.c_tapea; 183 trecno++; 184 spcl.c_tapea++; 185 if (trecno >= ntrec) 186 flushtape(); 187 } 188 189 void 190 dumpblock(blkno, size) 191 daddr_t blkno; 192 int size; 193 { 194 int avail, tpblks, dblkno; 195 196 dblkno = fsbtodb(sblock, blkno); 197 tpblks = size >> tp_bshift; 198 while ((avail = MIN(tpblks, ntrec - trecno)) > 0) { 199 slp->req[trecno].dblk = dblkno; 200 slp->req[trecno].count = avail; 201 trecno += avail; 202 spcl.c_tapea += avail; 203 if (trecno >= ntrec) 204 flushtape(); 205 dblkno += avail << (tp_bshift - dev_bshift); 206 tpblks -= avail; 207 } 208 } 209 210 int nogripe = 0; 211 212 void 213 tperror(signo) 214 int signo; 215 { 216 217 if (pipeout) { 218 msg("write error on %s\n", tape); 219 quit("Cannot recover\n"); 220 /* NOTREACHED */ 221 } 222 msg("write error %d blocks into volume %d\n", blocksthisvol, tapeno); 223 broadcast("DUMP WRITE ERROR!\n"); 224 if (!query("Do you want to restart?")) 225 dumpabort(0); 226 msg("Closing this volume. Prepare to restart with new media;\n"); 227 msg("this dump volume will be rewritten.\n"); 228 killall(); 229 nogripe = 1; 230 close_rewind(); 231 Exit(X_REWRITE); 232 } 233 234 void 235 sigpipe(signo) 236 int signo; 237 { 238 239 quit("Broken pipe\n"); 240 } 241 242 static void 243 flushtape() 244 { 245 int i, blks, got; 246 long lastfirstrec; 247 248 int siz = (char *)nextblock - (char *)slp->req; 249 250 slp->req[trecno].count = 0; /* Sentinel */ 251 252 if (atomic(write, slp->fd, (char *)slp->req, siz) != siz) 253 quit("error writing command pipe: %s\n", strerror(errno)); 254 slp->sent = 1; /* we sent a request, read the response later */ 255 256 lastfirstrec = slp->firstrec; 257 258 if (++slp >= &slaves[SLAVES]) 259 slp = &slaves[0]; 260 261 /* Read results back from next slave */ 262 if (slp->sent) { 263 if (atomic(read, slp->fd, (char *)&got, sizeof got) 264 != sizeof got) { 265 perror(" DUMP: error reading command pipe in master"); 266 dumpabort(0); 267 } 268 slp->sent = 0; 269 270 /* Check for end of tape */ 271 if (got < writesize) { 272 msg("End of tape detected\n"); 273 274 /* 275 * Drain the results, don't care what the values were. 276 * If we read them here then trewind won't... 277 */ 278 for (i = 0; i < SLAVES; i++) { 279 if (slaves[i].sent) { 280 if (atomic(read, slaves[i].fd, 281 (char *)&got, sizeof got) 282 != sizeof got) { 283 perror(" DUMP: error reading command pipe in master"); 284 dumpabort(0); 285 } 286 slaves[i].sent = 0; 287 } 288 } 289 290 close_rewind(); 291 rollforward(); 292 return; 293 } 294 } 295 296 blks = 0; 297 if (spcl.c_type != TS_END) { 298 for (i = 0; i < spcl.c_count; i++) 299 if (spcl.c_addr[i] != 0) 300 blks++; 301 } 302 slp->count = lastspclrec + blks + 1 - spcl.c_tapea; 303 slp->tapea = spcl.c_tapea; 304 slp->firstrec = lastfirstrec + ntrec; 305 slp->inode = curino; 306 nextblock = slp->tblock; 307 trecno = 0; 308 asize += tenths; 309 blockswritten += ntrec; 310 blocksthisvol += ntrec; 311 if (!pipeout && (blocksperfile ? 312 (blocksthisvol >= blocksperfile) : (asize > tsize))) { 313 close_rewind(); 314 startnewtape(0); 315 } 316 timeest(); 317 } 318 319 void 320 trewind() 321 { 322 int f; 323 int got; 324 325 for (f = 0; f < SLAVES; f++) { 326 /* 327 * Drain the results, but unlike EOT we DO (or should) care 328 * what the return values were, since if we detect EOT after 329 * we think we've written the last blocks to the tape anyway, 330 * we have to replay those blocks with rollforward. 331 * 332 * fixme: punt for now. 333 */ 334 if (slaves[f].sent) { 335 if (atomic(read, slaves[f].fd, (char *)&got, sizeof got) 336 != sizeof got) { 337 perror(" DUMP: error reading command pipe in master"); 338 dumpabort(0); 339 } 340 slaves[f].sent = 0; 341 if (got != writesize) { 342 msg("EOT detected in last 2 tape records!\n"); 343 msg("Use a longer tape, decrease the size estimate\n"); 344 quit("or use no size estimate at all.\n"); 345 } 346 } 347 (void) close(slaves[f].fd); 348 } 349 while (wait((int *)NULL) >= 0) /* wait for any signals from slaves */ 350 /* void */; 351 352 if (pipeout) 353 return; 354 355 msg("Closing %s\n", tape); 356 357 #ifdef RDUMP 358 if (host) { 359 rmtclose(); 360 while (rmtopen(tape, 0) < 0) 361 sleep(10); 362 rmtclose(); 363 return; 364 } 365 #endif 366 (void) close(tapefd); 367 while ((f = open(tape, 0)) < 0) 368 sleep (10); 369 (void) close(f); 370 } 371 372 void 373 close_rewind() 374 { 375 trewind(); 376 if (nexttape) 377 return; 378 if (!nogripe) { 379 msg("Change Volumes: Mount volume #%d\n", tapeno+1); 380 broadcast("CHANGE DUMP VOLUMES!\7\7\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 } 388 389 void 390 rollforward() 391 { 392 register struct req *p, *q, *prev; 393 register struct slave *tslp; 394 int i, size, savedtapea, got; 395 union u_spcl *ntb, *otb; 396 tslp = &slaves[SLAVES]; 397 ntb = (union u_spcl *)tslp->tblock[1]; 398 399 /* 400 * Each of the N slaves should have requests that need to 401 * be replayed on the next tape. Use the extra slave buffers 402 * (slaves[SLAVES]) to construct request lists to be sent to 403 * each slave in turn. 404 */ 405 for (i = 0; i < SLAVES; i++) { 406 q = &tslp->req[1]; 407 otb = (union u_spcl *)slp->tblock; 408 409 /* 410 * For each request in the current slave, copy it to tslp. 411 */ 412 413 prev = NULL; 414 for (p = slp->req; p->count > 0; p += p->count) { 415 *q = *p; 416 if (p->dblk == 0) 417 *ntb++ = *otb++; /* copy the datablock also */ 418 prev = q; 419 q += q->count; 420 } 421 if (prev == NULL) 422 quit("rollforward: protocol botch"); 423 if (prev->dblk != 0) 424 prev->count -= 1; 425 else 426 ntb--; 427 q -= 1; 428 q->count = 0; 429 q = &tslp->req[0]; 430 if (i == 0) { 431 q->dblk = 0; 432 q->count = 1; 433 trecno = 0; 434 nextblock = tslp->tblock; 435 savedtapea = spcl.c_tapea; 436 spcl.c_tapea = slp->tapea; 437 startnewtape(0); 438 spcl.c_tapea = savedtapea; 439 lastspclrec = savedtapea - 1; 440 } 441 size = (char *)ntb - (char *)q; 442 if (atomic(write, slp->fd, (char *)q, size) != size) { 443 perror(" DUMP: error writing command pipe"); 444 dumpabort(0); 445 } 446 slp->sent = 1; 447 if (++slp >= &slaves[SLAVES]) 448 slp = &slaves[0]; 449 450 q->count = 1; 451 452 if (prev->dblk != 0) { 453 /* 454 * If the last one was a disk block, make the 455 * first of this one be the last bit of that disk 456 * block... 457 */ 458 q->dblk = prev->dblk + 459 prev->count * (TP_BSIZE / DEV_BSIZE); 460 ntb = (union u_spcl *)tslp->tblock; 461 } else { 462 /* 463 * It wasn't a disk block. Copy the data to its 464 * new location in the buffer. 465 */ 466 q->dblk = 0; 467 *((union u_spcl *)tslp->tblock) = *ntb; 468 ntb = (union u_spcl *)tslp->tblock[1]; 469 } 470 } 471 slp->req[0] = *q; 472 nextblock = slp->tblock; 473 if (q->dblk == 0) 474 nextblock++; 475 trecno = 1; 476 477 /* 478 * Clear the first slaves' response. One hopes that it 479 * worked ok, otherwise the tape is much too short! 480 */ 481 if (slp->sent) { 482 if (atomic(read, slp->fd, (char *)&got, sizeof got) 483 != sizeof got) { 484 perror(" DUMP: error reading command pipe in master"); 485 dumpabort(0); 486 } 487 slp->sent = 0; 488 489 if (got != writesize) { 490 quit("EOT detected at start of the tape!\n"); 491 } 492 } 493 } 494 495 /* 496 * We implement taking and restoring checkpoints on the tape level. 497 * When each tape is opened, a new process is created by forking; this 498 * saves all of the necessary context in the parent. The child 499 * continues the dump; the parent waits around, saving the context. 500 * If the child returns X_REWRITE, then it had problems writing that tape; 501 * this causes the parent to fork again, duplicating the context, and 502 * everything continues as if nothing had happened. 503 */ 504 void 505 startnewtape(top) 506 int top; 507 { 508 int parentpid; 509 int childpid; 510 int status; 511 int waitpid; 512 char *p; 513 #ifdef sunos 514 void (*interrupt_save)(); 515 #else 516 sig_t interrupt_save; 517 #endif 518 519 interrupt_save = signal(SIGINT, SIG_IGN); 520 parentpid = getpid(); 521 522 restore_check_point: 523 (void)signal(SIGINT, interrupt_save); 524 /* 525 * All signals are inherited... 526 */ 527 childpid = fork(); 528 if (childpid < 0) { 529 msg("Context save fork fails in parent %d\n", parentpid); 530 Exit(X_ABORT); 531 } 532 if (childpid != 0) { 533 /* 534 * PARENT: 535 * save the context by waiting 536 * until the child doing all of the work returns. 537 * don't catch the interrupt 538 */ 539 signal(SIGINT, SIG_IGN); 540 #ifdef TDEBUG 541 msg("Tape: %d; parent process: %d child process %d\n", 542 tapeno+1, parentpid, childpid); 543 #endif /* TDEBUG */ 544 while ((waitpid = wait(&status)) != childpid) 545 msg("Parent %d waiting for child %d has another child %d return\n", 546 parentpid, childpid, waitpid); 547 if (status & 0xFF) { 548 msg("Child %d returns LOB status %o\n", 549 childpid, status&0xFF); 550 } 551 status = (status >> 8) & 0xFF; 552 #ifdef TDEBUG 553 switch(status) { 554 case X_FINOK: 555 msg("Child %d finishes X_FINOK\n", childpid); 556 break; 557 case X_ABORT: 558 msg("Child %d finishes X_ABORT\n", childpid); 559 break; 560 case X_REWRITE: 561 msg("Child %d finishes X_REWRITE\n", childpid); 562 break; 563 default: 564 msg("Child %d finishes unknown %d\n", 565 childpid, status); 566 break; 567 } 568 #endif /* TDEBUG */ 569 switch(status) { 570 case X_FINOK: 571 Exit(X_FINOK); 572 case X_ABORT: 573 Exit(X_ABORT); 574 case X_REWRITE: 575 goto restore_check_point; 576 default: 577 msg("Bad return code from dump: %d\n", status); 578 Exit(X_ABORT); 579 } 580 /*NOTREACHED*/ 581 } else { /* we are the child; just continue */ 582 #ifdef TDEBUG 583 sleep(4); /* allow time for parent's message to get out */ 584 msg("Child on Tape %d has parent %d, my pid = %d\n", 585 tapeno+1, parentpid, getpid()); 586 #endif /* TDEBUG */ 587 /* 588 * If we have a name like "/dev/rmt0,/dev/rmt1", 589 * use the name before the comma first, and save 590 * the remaining names for subsequent volumes. 591 */ 592 tapeno++; /* current tape sequence */ 593 if (nexttape || strchr(tape, ',')) { 594 if (nexttape && *nexttape) 595 tape = nexttape; 596 if ((p = strchr(tape, ',')) != NULL) { 597 *p = '\0'; 598 nexttape = p + 1; 599 } else 600 nexttape = NULL; 601 msg("Dumping volume %d on %s\n", tapeno, tape); 602 } 603 #ifdef RDUMP 604 while ((tapefd = (host ? rmtopen(tape, 2) : 605 pipeout ? 1 : open(tape, O_WRONLY|O_CREAT, 0666))) < 0) 606 #else 607 while ((tapefd = (pipeout ? 1 : 608 open(tape, O_WRONLY|O_CREAT, 0666))) < 0) 609 #endif 610 { 611 msg("Cannot open output \"%s\".\n", tape); 612 if (!query("Do you want to retry the open?")) 613 dumpabort(0); 614 } 615 616 enslave(); /* Share open tape file descriptor with slaves */ 617 618 asize = 0; 619 blocksthisvol = 0; 620 if (top) 621 newtape++; /* new tape signal */ 622 spcl.c_count = slp->count; 623 /* 624 * measure firstrec in TP_BSIZE units since restore doesn't 625 * know the correct ntrec value... 626 */ 627 spcl.c_firstrec = slp->firstrec; 628 spcl.c_volume++; 629 spcl.c_type = TS_TAPE; 630 spcl.c_flags |= DR_NEWHEADER; 631 writeheader((ino_t)slp->inode); 632 spcl.c_flags &=~ DR_NEWHEADER; 633 if (tapeno > 1) 634 msg("Volume %d begins with blocks from inode %d\n", 635 tapeno, slp->inode); 636 } 637 } 638 639 void 640 dumpabort(signo) 641 int signo; 642 { 643 644 if (master != 0 && master != getpid()) 645 /* Signals master to call dumpabort */ 646 (void) kill(master, SIGTERM); 647 else { 648 killall(); 649 msg("The ENTIRE dump is aborted.\n"); 650 } 651 #ifdef RDUMP 652 rmtclose(); 653 #endif 654 Exit(X_ABORT); 655 } 656 657 __dead void 658 Exit(status) 659 int status; 660 { 661 662 #ifdef TDEBUG 663 msg("pid = %d exits with status %d\n", getpid(), status); 664 #endif /* TDEBUG */ 665 exit(status); 666 } 667 668 /* 669 * proceed - handler for SIGUSR2, used to synchronize IO between the slaves. 670 */ 671 void 672 proceed(signo) 673 int signo; 674 { 675 676 if (ready) 677 longjmp(jmpbuf, 1); 678 caught++; 679 } 680 681 void 682 enslave() 683 { 684 int cmd[2]; 685 register int i, j; 686 687 master = getpid(); 688 689 signal(SIGTERM, dumpabort); /* Slave sends SIGTERM on dumpabort() */ 690 signal(SIGPIPE, sigpipe); 691 signal(SIGUSR1, tperror); /* Slave sends SIGUSR1 on tape errors */ 692 signal(SIGUSR2, proceed); /* Slave sends SIGUSR2 to next slave */ 693 694 for (i = 0; i < SLAVES; i++) { 695 if (i == slp - &slaves[0]) { 696 caught = 1; 697 } else { 698 caught = 0; 699 } 700 701 if (socketpair(AF_UNIX, SOCK_STREAM, 0, cmd) < 0 || 702 (slaves[i].pid = fork()) < 0) 703 quit("too many slaves, %d (recompile smaller): %s\n", 704 i, strerror(errno)); 705 706 slaves[i].fd = cmd[1]; 707 slaves[i].sent = 0; 708 if (slaves[i].pid == 0) { /* Slave starts up here */ 709 for (j = 0; j <= i; j++) 710 (void) close(slaves[j].fd); 711 signal(SIGINT, SIG_IGN); /* Master handles this */ 712 doslave(cmd[0], i); 713 Exit(X_FINOK); 714 } 715 } 716 717 for (i = 0; i < SLAVES; i++) 718 (void) atomic(write, slaves[i].fd, 719 (char *) &slaves[(i + 1) % SLAVES].pid, 720 sizeof slaves[0].pid); 721 722 master = 0; 723 } 724 725 void 726 killall() 727 { 728 register int i; 729 730 for (i = 0; i < SLAVES; i++) 731 if (slaves[i].pid > 0) 732 (void) kill(slaves[i].pid, SIGKILL); 733 } 734 735 /* 736 * Synchronization - each process has a lockfile, and shares file 737 * descriptors to the following process's lockfile. When our write 738 * completes, we release our lock on the following process's lock- 739 * file, allowing the following process to lock it and proceed. We 740 * get the lock back for the next cycle by swapping descriptors. 741 */ 742 static void 743 doslave(cmd, slave_number) 744 register int cmd; 745 int slave_number; 746 { 747 register int nread; 748 int nextslave, size, wrote, eot_count; 749 sigset_t sigset; 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 if (eot_count > 0) 822 size = 0; 823 824 /* 825 * fixme: Pyramids running OSx return ENOSPC 826 * at EOT on 1/2 inch drives. 827 */ 828 if (size < 0) { 829 (void) kill(master, SIGUSR1); 830 sigemptyset(&sigset); 831 for (;;) 832 sigsuspend(&sigset); 833 } else { 834 /* 835 * pass size of write back to master 836 * (for EOT handling) 837 */ 838 (void) atomic(write, cmd, (char *)&size, sizeof size); 839 } 840 841 /* 842 * If partial write, don't want next slave to go. 843 * Also jolts him awake. 844 */ 845 (void) kill(nextslave, SIGUSR2); 846 } 847 if (nread != 0) 848 quit("error reading command pipe: %s\n", strerror(errno)); 849 } 850 851 /* 852 * Since a read from a pipe may not return all we asked for, 853 * or a write may not write all we ask if we get a signal, 854 * loop until the count is satisfied (or error). 855 */ 856 static ssize_t 857 atomic(func, fd, buf, count) 858 ssize_t (*func)(); 859 int fd; 860 char *buf; 861 int count; 862 { 863 ssize_t got, need = count; 864 865 while ((got = (*func)(fd, buf, need)) > 0 && (need -= got) > 0) 866 buf += got; 867 return (got < 0 ? got : count - need); 868 } 869