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[] = "@(#)tape.c 8.2 (Berkeley) 3/17/94"; 36 #endif /* not lint */ 37 38 #include <sys/param.h> 39 #include <sys/socket.h> 40 #include <sys/time.h> 41 #include <sys/wait.h> 42 #ifdef sunos 43 #include <sys/vnode.h> 44 45 #include <ufs/fs.h> 46 #include <ufs/inode.h> 47 #else 48 #include <ufs/ffs/fs.h> 49 #include <ufs/ufs/dinode.h> 50 #endif 51 52 #include <protocols/dumprestore.h> 53 54 #include <errno.h> 55 #include <fcntl.h> 56 #include <setjmp.h> 57 #include <signal.h> 58 #include <stdio.h> 59 #ifdef __STDC__ 60 #include <stdlib.h> 61 #include <string.h> 62 #include <unistd.h> 63 #else 64 int write(), read(); 65 #endif 66 67 #include "dump.h" 68 #include "pathnames.h" 69 70 int writesize; /* size of malloc()ed buffer for tape */ 71 long lastspclrec = -1; /* tape block number of last written header */ 72 int trecno = 0; /* next record to write in current block */ 73 extern long blocksperfile; /* number of blocks per output file */ 74 long blocksthisvol; /* number of blocks on current output file */ 75 extern int ntrec; /* blocking factor on tape */ 76 extern int cartridge; 77 extern char *host; 78 char *nexttape; 79 80 static int atomic __P((int (*)(), int, char *, int)); 81 static void doslave __P((int, int)); 82 static void enslave __P((void)); 83 static void flushtape __P((void)); 84 static void killall __P((void)); 85 static void rollforward __P((void)); 86 87 /* 88 * Concurrent dump mods (Caltech) - disk block reading and tape writing 89 * are exported to several slave processes. While one slave writes the 90 * tape, the others read disk blocks; they pass control of the tape in 91 * a ring via signals. The parent process traverses the filesystem and 92 * sends writeheader()'s and lists of daddr's to the slaves via pipes. 93 * The following structure defines the instruction packets sent to slaves. 94 */ 95 struct req { 96 daddr_t dblk; 97 int count; 98 }; 99 int reqsiz; 100 101 #define SLAVES 3 /* 1 slave writing, 1 reading, 1 for slack */ 102 struct slave { 103 int tapea; /* header number at start of this chunk */ 104 int count; /* count to next header (used for TS_TAPE */ 105 /* after EOT) */ 106 int inode; /* inode that we are currently dealing with */ 107 int fd; /* FD for this slave */ 108 int pid; /* PID for this slave */ 109 int sent; /* 1 == we've sent this slave requests */ 110 int firstrec; /* record number of this block */ 111 char (*tblock)[TP_BSIZE]; /* buffer for data blocks */ 112 struct req *req; /* buffer for requests */ 113 } slaves[SLAVES+1]; 114 struct slave *slp; 115 116 char (*nextblock)[TP_BSIZE]; 117 118 int master; /* pid of master, for sending error signals */ 119 int tenths; /* length of tape used per block written */ 120 static int caught; /* have we caught the signal to proceed? */ 121 static int ready; /* have we reached the lock point without having */ 122 /* received the SIGUSR2 signal from the prev slave? */ 123 static jmp_buf jmpbuf; /* where to jump to if we are ready when the */ 124 /* SIGUSR2 arrives from the previous slave */ 125 126 int 127 alloctape() 128 { 129 int pgoff = getpagesize() - 1; 130 char *buf; 131 int i; 132 133 writesize = ntrec * TP_BSIZE; 134 reqsiz = (ntrec + 1) * sizeof(struct req); 135 /* 136 * CDC 92181's and 92185's make 0.8" gaps in 1600-bpi start/stop mode 137 * (see DEC TU80 User's Guide). The shorter gaps of 6250-bpi require 138 * repositioning after stopping, i.e, streaming mode, where the gap is 139 * variable, 0.30" to 0.45". The gap is maximal when the tape stops. 140 */ 141 if (blocksperfile == 0) 142 tenths = writesize / density + 143 (cartridge ? 16 : density == 625 ? 5 : 8); 144 /* 145 * Allocate tape buffer contiguous with the array of instruction 146 * packets, so flushtape() can write them together with one write(). 147 * Align tape buffer on page boundary to speed up tape write(). 148 */ 149 for (i = 0; i <= SLAVES; i++) { 150 buf = (char *) 151 malloc((unsigned)(reqsiz + writesize + pgoff + TP_BSIZE)); 152 if (buf == NULL) 153 return(0); 154 slaves[i].tblock = (char (*)[TP_BSIZE]) 155 (((long)&buf[ntrec + 1] + pgoff) &~ pgoff); 156 slaves[i].req = (struct req *)slaves[i].tblock - ntrec - 1; 157 } 158 slp = &slaves[0]; 159 slp->count = 1; 160 slp->tapea = 0; 161 slp->firstrec = 0; 162 nextblock = slp->tblock; 163 return(1); 164 } 165 166 void 167 writerec(dp, isspcl) 168 char *dp; 169 int isspcl; 170 { 171 172 slp->req[trecno].dblk = (daddr_t)0; 173 slp->req[trecno].count = 1; 174 *(union u_spcl *)(*(nextblock)++) = *(union u_spcl *)dp; 175 if (isspcl) 176 lastspclrec = spcl.c_tapea; 177 trecno++; 178 spcl.c_tapea++; 179 if (trecno >= ntrec) 180 flushtape(); 181 } 182 183 void 184 dumpblock(blkno, size) 185 daddr_t blkno; 186 int size; 187 { 188 int avail, tpblks, dblkno; 189 190 dblkno = fsbtodb(sblock, blkno); 191 tpblks = size >> tp_bshift; 192 while ((avail = MIN(tpblks, ntrec - trecno)) > 0) { 193 slp->req[trecno].dblk = dblkno; 194 slp->req[trecno].count = avail; 195 trecno += avail; 196 spcl.c_tapea += avail; 197 if (trecno >= ntrec) 198 flushtape(); 199 dblkno += avail << (tp_bshift - dev_bshift); 200 tpblks -= avail; 201 } 202 } 203 204 int nogripe = 0; 205 206 void 207 tperror(signo) 208 int signo; 209 { 210 211 if (pipeout) { 212 msg("write error on %s\n", tape); 213 quit("Cannot recover\n"); 214 /* NOTREACHED */ 215 } 216 msg("write error %d blocks into volume %d\n", blocksthisvol, tapeno); 217 broadcast("DUMP WRITE ERROR!\n"); 218 if (!query("Do you want to restart?")) 219 dumpabort(0); 220 msg("Closing this volume. Prepare to restart with new media;\n"); 221 msg("this dump volume will be rewritten.\n"); 222 killall(); 223 nogripe = 1; 224 close_rewind(); 225 Exit(X_REWRITE); 226 } 227 228 void 229 sigpipe(signo) 230 int signo; 231 { 232 233 quit("Broken pipe\n"); 234 } 235 236 static void 237 flushtape() 238 { 239 int i, blks, got; 240 long lastfirstrec; 241 242 int siz = (char *)nextblock - (char *)slp->req; 243 244 slp->req[trecno].count = 0; /* Sentinel */ 245 246 if (atomic(write, slp->fd, (char *)slp->req, siz) != siz) 247 quit("error writing command pipe: %s\n", strerror(errno)); 248 slp->sent = 1; /* we sent a request, read the response later */ 249 250 lastfirstrec = slp->firstrec; 251 252 if (++slp >= &slaves[SLAVES]) 253 slp = &slaves[0]; 254 255 /* Read results back from next slave */ 256 if (slp->sent) { 257 if (atomic(read, slp->fd, (char *)&got, sizeof got) 258 != sizeof got) { 259 perror(" DUMP: error reading command pipe in master"); 260 dumpabort(0); 261 } 262 slp->sent = 0; 263 264 /* Check for end of tape */ 265 if (got < writesize) { 266 msg("End of tape detected\n"); 267 268 /* 269 * Drain the results, don't care what the values were. 270 * If we read them here then trewind won't... 271 */ 272 for (i = 0; i < SLAVES; i++) { 273 if (slaves[i].sent) { 274 if (atomic(read, slaves[i].fd, 275 (char *)&got, sizeof got) 276 != sizeof got) { 277 perror(" DUMP: error reading command pipe in master"); 278 dumpabort(0); 279 } 280 slaves[i].sent = 0; 281 } 282 } 283 284 close_rewind(); 285 rollforward(); 286 return; 287 } 288 } 289 290 blks = 0; 291 if (spcl.c_type != TS_END) { 292 for (i = 0; i < spcl.c_count; i++) 293 if (spcl.c_addr[i] != 0) 294 blks++; 295 } 296 slp->count = lastspclrec + blks + 1 - spcl.c_tapea; 297 slp->tapea = spcl.c_tapea; 298 slp->firstrec = lastfirstrec + ntrec; 299 slp->inode = curino; 300 nextblock = slp->tblock; 301 trecno = 0; 302 asize += tenths; 303 blockswritten += ntrec; 304 blocksthisvol += ntrec; 305 if (!pipeout && (blocksperfile ? 306 (blocksthisvol >= blocksperfile) : (asize > tsize))) { 307 close_rewind(); 308 startnewtape(0); 309 } 310 timeest(); 311 } 312 313 void 314 trewind() 315 { 316 int f; 317 int got; 318 319 for (f = 0; f < SLAVES; f++) { 320 /* 321 * Drain the results, but unlike EOT we DO (or should) care 322 * what the return values were, since if we detect EOT after 323 * we think we've written the last blocks to the tape anyway, 324 * we have to replay those blocks with rollforward. 325 * 326 * fixme: punt for now. 327 */ 328 if (slaves[f].sent) { 329 if (atomic(read, slaves[f].fd, (char *)&got, sizeof got) 330 != sizeof got) { 331 perror(" DUMP: error reading command pipe in master"); 332 dumpabort(0); 333 } 334 slaves[f].sent = 0; 335 if (got != writesize) { 336 msg("EOT detected in last 2 tape records!\n"); 337 msg("Use a longer tape, decrease the size estimate\n"); 338 quit("or use no size estimate at all.\n"); 339 } 340 } 341 (void) close(slaves[f].fd); 342 } 343 while (wait((int *)NULL) >= 0) /* wait for any signals from slaves */ 344 /* void */; 345 346 if (pipeout) 347 return; 348 349 msg("Closing %s\n", tape); 350 351 #ifdef RDUMP 352 if (host) { 353 rmtclose(); 354 while (rmtopen(tape, 0) < 0) 355 sleep(10); 356 rmtclose(); 357 return; 358 } 359 #endif 360 (void) close(tapefd); 361 while ((f = open(tape, 0)) < 0) 362 sleep (10); 363 (void) close(f); 364 } 365 366 void 367 close_rewind() 368 { 369 trewind(); 370 if (nexttape) 371 return; 372 if (!nogripe) { 373 msg("Change Volumes: Mount volume #%d\n", tapeno+1); 374 broadcast("CHANGE DUMP VOLUMES!\7\7\n"); 375 } 376 while (!query("Is the new volume mounted and ready to go?")) 377 if (query("Do you want to abort?")) { 378 dumpabort(0); 379 /*NOTREACHED*/ 380 } 381 } 382 383 void 384 rollforward() 385 { 386 register struct req *p, *q, *prev; 387 register struct slave *tslp; 388 int i, size, savedtapea, got; 389 union u_spcl *ntb, *otb; 390 tslp = &slaves[SLAVES]; 391 ntb = (union u_spcl *)tslp->tblock[1]; 392 393 /* 394 * Each of the N slaves should have requests that need to 395 * be replayed on the next tape. Use the extra slave buffers 396 * (slaves[SLAVES]) to construct request lists to be sent to 397 * each slave in turn. 398 */ 399 for (i = 0; i < SLAVES; i++) { 400 q = &tslp->req[1]; 401 otb = (union u_spcl *)slp->tblock; 402 403 /* 404 * For each request in the current slave, copy it to tslp. 405 */ 406 407 prev = NULL; 408 for (p = slp->req; p->count > 0; p += p->count) { 409 *q = *p; 410 if (p->dblk == 0) 411 *ntb++ = *otb++; /* copy the datablock also */ 412 prev = q; 413 q += q->count; 414 } 415 if (prev == NULL) 416 quit("rollforward: protocol botch"); 417 if (prev->dblk != 0) 418 prev->count -= 1; 419 else 420 ntb--; 421 q -= 1; 422 q->count = 0; 423 q = &tslp->req[0]; 424 if (i == 0) { 425 q->dblk = 0; 426 q->count = 1; 427 trecno = 0; 428 nextblock = tslp->tblock; 429 savedtapea = spcl.c_tapea; 430 spcl.c_tapea = slp->tapea; 431 startnewtape(0); 432 spcl.c_tapea = savedtapea; 433 lastspclrec = savedtapea - 1; 434 } 435 size = (char *)ntb - (char *)q; 436 if (atomic(write, slp->fd, (char *)q, size) != size) { 437 perror(" DUMP: error writing command pipe"); 438 dumpabort(0); 439 } 440 slp->sent = 1; 441 if (++slp >= &slaves[SLAVES]) 442 slp = &slaves[0]; 443 444 q->count = 1; 445 446 if (prev->dblk != 0) { 447 /* 448 * If the last one was a disk block, make the 449 * first of this one be the last bit of that disk 450 * block... 451 */ 452 q->dblk = prev->dblk + 453 prev->count * (TP_BSIZE / DEV_BSIZE); 454 ntb = (union u_spcl *)tslp->tblock; 455 } else { 456 /* 457 * It wasn't a disk block. Copy the data to its 458 * new location in the buffer. 459 */ 460 q->dblk = 0; 461 *((union u_spcl *)tslp->tblock) = *ntb; 462 ntb = (union u_spcl *)tslp->tblock[1]; 463 } 464 } 465 slp->req[0] = *q; 466 nextblock = slp->tblock; 467 if (q->dblk == 0) 468 nextblock++; 469 trecno = 1; 470 471 /* 472 * Clear the first slaves' response. One hopes that it 473 * worked ok, otherwise the tape is much too short! 474 */ 475 if (slp->sent) { 476 if (atomic(read, slp->fd, (char *)&got, sizeof got) 477 != sizeof got) { 478 perror(" DUMP: error reading command pipe in master"); 479 dumpabort(0); 480 } 481 slp->sent = 0; 482 483 if (got != writesize) { 484 quit("EOT detected at start of the tape!\n"); 485 } 486 } 487 } 488 489 /* 490 * We implement taking and restoring checkpoints on the tape level. 491 * When each tape is opened, a new process is created by forking; this 492 * saves all of the necessary context in the parent. The child 493 * continues the dump; the parent waits around, saving the context. 494 * If the child returns X_REWRITE, then it had problems writing that tape; 495 * this causes the parent to fork again, duplicating the context, and 496 * everything continues as if nothing had happened. 497 */ 498 void 499 startnewtape(top) 500 int top; 501 { 502 int parentpid; 503 int childpid; 504 int status; 505 int waitpid; 506 char *p; 507 #ifdef sunos 508 void (*interrupt_save)(); 509 #else 510 sig_t interrupt_save; 511 #endif 512 513 interrupt_save = signal(SIGINT, SIG_IGN); 514 parentpid = getpid(); 515 516 restore_check_point: 517 (void)signal(SIGINT, interrupt_save); 518 /* 519 * All signals are inherited... 520 */ 521 childpid = fork(); 522 if (childpid < 0) { 523 msg("Context save fork fails in parent %d\n", parentpid); 524 Exit(X_ABORT); 525 } 526 if (childpid != 0) { 527 /* 528 * PARENT: 529 * save the context by waiting 530 * until the child doing all of the work returns. 531 * don't catch the interrupt 532 */ 533 signal(SIGINT, SIG_IGN); 534 #ifdef TDEBUG 535 msg("Tape: %d; parent process: %d child process %d\n", 536 tapeno+1, parentpid, childpid); 537 #endif /* TDEBUG */ 538 while ((waitpid = wait(&status)) != childpid) 539 msg("Parent %d waiting for child %d has another child %d return\n", 540 parentpid, childpid, waitpid); 541 if (status & 0xFF) { 542 msg("Child %d returns LOB status %o\n", 543 childpid, status&0xFF); 544 } 545 status = (status >> 8) & 0xFF; 546 #ifdef TDEBUG 547 switch(status) { 548 case X_FINOK: 549 msg("Child %d finishes X_FINOK\n", childpid); 550 break; 551 case X_ABORT: 552 msg("Child %d finishes X_ABORT\n", childpid); 553 break; 554 case X_REWRITE: 555 msg("Child %d finishes X_REWRITE\n", childpid); 556 break; 557 default: 558 msg("Child %d finishes unknown %d\n", 559 childpid, status); 560 break; 561 } 562 #endif /* TDEBUG */ 563 switch(status) { 564 case X_FINOK: 565 Exit(X_FINOK); 566 case X_ABORT: 567 Exit(X_ABORT); 568 case X_REWRITE: 569 goto restore_check_point; 570 default: 571 msg("Bad return code from dump: %d\n", status); 572 Exit(X_ABORT); 573 } 574 /*NOTREACHED*/ 575 } else { /* we are the child; just continue */ 576 #ifdef TDEBUG 577 sleep(4); /* allow time for parent's message to get out */ 578 msg("Child on Tape %d has parent %d, my pid = %d\n", 579 tapeno+1, parentpid, getpid()); 580 #endif /* TDEBUG */ 581 /* 582 * If we have a name like "/dev/rmt0,/dev/rmt1", 583 * use the name before the comma first, and save 584 * the remaining names for subsequent volumes. 585 */ 586 tapeno++; /* current tape sequence */ 587 if (nexttape || index(tape, ',')) { 588 if (nexttape && *nexttape) 589 tape = nexttape; 590 if ((p = index(tape, ',')) != NULL) { 591 *p = '\0'; 592 nexttape = p + 1; 593 } else 594 nexttape = NULL; 595 msg("Dumping volume %d on %s\n", tapeno, tape); 596 } 597 #ifdef RDUMP 598 while ((tapefd = (host ? rmtopen(tape, 2) : 599 pipeout ? 1 : open(tape, O_WRONLY|O_CREAT, 0666))) < 0) 600 #else 601 while ((tapefd = (pipeout ? 1 : 602 open(tape, O_WRONLY|O_CREAT, 0666))) < 0) 603 #endif 604 { 605 msg("Cannot open output \"%s\".\n", tape); 606 if (!query("Do you want to retry the open?")) 607 dumpabort(0); 608 } 609 610 enslave(); /* Share open tape file descriptor with slaves */ 611 612 asize = 0; 613 blocksthisvol = 0; 614 if (top) 615 newtape++; /* new tape signal */ 616 spcl.c_count = slp->count; 617 /* 618 * measure firstrec in TP_BSIZE units since restore doesn't 619 * know the correct ntrec value... 620 */ 621 spcl.c_firstrec = slp->firstrec; 622 spcl.c_volume++; 623 spcl.c_type = TS_TAPE; 624 spcl.c_flags |= DR_NEWHEADER; 625 writeheader((ino_t)slp->inode); 626 spcl.c_flags &=~ DR_NEWHEADER; 627 if (tapeno > 1) 628 msg("Volume %d begins with blocks from inode %d\n", 629 tapeno, slp->inode); 630 } 631 } 632 633 void 634 dumpabort(signo) 635 int signo; 636 { 637 638 if (master != 0 && master != getpid()) 639 /* Signals master to call dumpabort */ 640 (void) kill(master, SIGTERM); 641 else { 642 killall(); 643 msg("The ENTIRE dump is aborted.\n"); 644 } 645 #ifdef RDUMP 646 rmtclose(); 647 #endif 648 Exit(X_ABORT); 649 } 650 651 void 652 Exit(status) 653 int status; 654 { 655 656 #ifdef TDEBUG 657 msg("pid = %d exits with status %d\n", getpid(), status); 658 #endif /* TDEBUG */ 659 exit(status); 660 } 661 662 /* 663 * proceed - handler for SIGUSR2, used to synchronize IO between the slaves. 664 */ 665 void 666 proceed(signo) 667 int signo; 668 { 669 670 if (ready) 671 longjmp(jmpbuf, 1); 672 caught++; 673 } 674 675 void 676 enslave() 677 { 678 int cmd[2]; 679 register int i, j; 680 681 master = getpid(); 682 683 signal(SIGTERM, dumpabort); /* Slave sends SIGTERM on dumpabort() */ 684 signal(SIGPIPE, sigpipe); 685 signal(SIGUSR1, tperror); /* Slave sends SIGUSR1 on tape errors */ 686 signal(SIGUSR2, proceed); /* Slave sends SIGUSR2 to next slave */ 687 688 for (i = 0; i < SLAVES; i++) { 689 if (i == slp - &slaves[0]) { 690 caught = 1; 691 } else { 692 caught = 0; 693 } 694 695 if (socketpair(AF_UNIX, SOCK_STREAM, 0, cmd) < 0 || 696 (slaves[i].pid = fork()) < 0) 697 quit("too many slaves, %d (recompile smaller): %s\n", 698 i, strerror(errno)); 699 700 slaves[i].fd = cmd[1]; 701 slaves[i].sent = 0; 702 if (slaves[i].pid == 0) { /* Slave starts up here */ 703 for (j = 0; j <= i; j++) 704 (void) close(slaves[j].fd); 705 signal(SIGINT, SIG_IGN); /* Master handles this */ 706 doslave(cmd[0], i); 707 Exit(X_FINOK); 708 } 709 } 710 711 for (i = 0; i < SLAVES; i++) 712 (void) atomic(write, slaves[i].fd, 713 (char *) &slaves[(i + 1) % SLAVES].pid, 714 sizeof slaves[0].pid); 715 716 master = 0; 717 } 718 719 void 720 killall() 721 { 722 register int i; 723 724 for (i = 0; i < SLAVES; i++) 725 if (slaves[i].pid > 0) 726 (void) kill(slaves[i].pid, SIGKILL); 727 } 728 729 /* 730 * Synchronization - each process has a lockfile, and shares file 731 * descriptors to the following process's lockfile. When our write 732 * completes, we release our lock on the following process's lock- 733 * file, allowing the following process to lock it and proceed. We 734 * get the lock back for the next cycle by swapping descriptors. 735 */ 736 static void 737 doslave(cmd, slave_number) 738 register int cmd; 739 int slave_number; 740 { 741 register int nread; 742 int nextslave, size, wrote, eot_count; 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 static int 849 atomic(func, fd, buf, count) 850 int (*func)(), fd; 851 char *buf; 852 int count; 853 { 854 int got, need = count; 855 856 while ((got = (*func)(fd, buf, need)) > 0 && (need -= got) > 0) 857 buf += got; 858 return (got < 0 ? got : count - need); 859 } 860