1 /* $OpenBSD: tape.c,v 1.48 2023/03/08 04:43:06 guenther Exp $ */ 2 /* $NetBSD: tape.c,v 1.11 1997/06/05 11:13:26 lukem Exp $ */ 3 4 /*- 5 * Copyright (c) 1980, 1991, 1993 6 * The Regents of the University of California. All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 #include <sys/param.h> /* MAXBSIZE DEV_BSIZE */ 34 #include <sys/socket.h> 35 #include <sys/time.h> 36 #include <sys/wait.h> 37 #include <sys/stat.h> 38 #include <ufs/ffs/fs.h> 39 #include <ufs/ufs/dinode.h> 40 41 #include <protocols/dumprestore.h> 42 43 #include <errno.h> 44 #include <fcntl.h> 45 #include <signal.h> 46 #include <stdio.h> 47 #include <stdlib.h> 48 #include <string.h> 49 #include <time.h> 50 #include <unistd.h> 51 #include <limits.h> 52 53 #include "dump.h" 54 #include "pathnames.h" 55 56 #define MINIMUM(a, b) (((a) < (b)) ? (a) : (b)) 57 58 ino_t curino; /* current inumber; used globally */ 59 int newtape; /* new tape flag */ 60 union u_spcl u_spcl; /* mapping of variables in a control block */ 61 62 static int tapefd; /* tape file descriptor */ 63 static int64_t asize; /* number of 0.1" units written on cur tape */ 64 static int writesize; /* size of malloc()ed buffer for tape */ 65 static int64_t lastspclrec = -1; /* tape block number of last written header */ 66 static int trecno = 0; /* next record to write in current block */ 67 static int64_t blocksthisvol; /* number of blocks on current output file */ 68 static char *nexttape; 69 70 static ssize_t atomic(ssize_t (*)(int, void *, size_t), int, char *, int); 71 static void doslave(int, int); 72 static void enslave(void); 73 static void flushtape(void); 74 static void killall(void); 75 static void rollforward(void); 76 77 void tperror(int signo); 78 void sigpipe(int signo); 79 void proceed(int signo); 80 81 /* 82 * Concurrent dump mods (Caltech) - disk block reading and tape writing 83 * are exported to several slave processes. While one slave writes the 84 * tape, the others read disk blocks; they pass control of the tape in 85 * a ring via signals. The parent process traverses the filesystem and 86 * sends writeheader()'s and lists of daddr's to the slaves via pipes. 87 * The following structure defines the instruction packets sent to slaves. 88 */ 89 struct req { 90 daddr_t dblk; 91 int count; 92 }; 93 static int reqsiz; 94 95 #define SLAVES 3 /* 1 slave writing, 1 reading, 1 for slack */ 96 static struct slave { 97 int64_t tapea; /* header number at start of this chunk */ 98 int64_t firstrec; /* record number of this block */ 99 int count; /* count to next header (used for TS_TAPE */ 100 /* after EOT) */ 101 int inode; /* inode that we are currently dealing with */ 102 int fd; /* FD for this slave */ 103 pid_t pid; /* PID for this slave */ 104 int sent; /* 1 == we've sent this slave requests */ 105 char (*tblock)[TP_BSIZE]; /* buffer for data blocks */ 106 struct req *req; /* buffer for requests */ 107 } slaves[SLAVES+1]; 108 static struct slave *slp; 109 110 static char (*nextblock)[TP_BSIZE]; 111 112 static time_t tstart_volume; /* time of volume start */ 113 static int64_t tapea_volume; /* value of spcl.c_tapea at volume start */ 114 115 static pid_t master; /* pid of master, for sending error signals */ 116 static int tenths; /* length of tape used per block written */ 117 static volatile sig_atomic_t caught; /* have we caught the signal to proceed? */ 118 119 int 120 alloctape(void) 121 { 122 int pgoff = getpagesize() - 1; 123 char *buf; 124 int i; 125 126 writesize = ntrec * TP_BSIZE; 127 reqsiz = (ntrec + 1) * sizeof(struct req); 128 /* 129 * CDC 92181's and 92185's make 0.8" gaps in 1600-bpi start/stop mode 130 * (see DEC TU80 User's Guide). The shorter gaps of 6250-bpi require 131 * repositioning after stopping, i.e, streaming mode, where the gap is 132 * variable, 0.30" to 0.45". The gap is maximal when the tape stops. 133 */ 134 if (blocksperfile == 0 && !unlimited) 135 tenths = writesize / density + 136 (cartridge ? 16 : density == 625 ? 5 : 8); 137 /* 138 * Allocate tape buffer contiguous with the array of instruction 139 * packets, so flushtape() can write them together with one write(). 140 * Align tape buffer on page boundary to speed up tape write(). 141 */ 142 for (i = 0; i <= SLAVES; i++) { 143 buf = malloc((unsigned)(reqsiz + writesize + pgoff + TP_BSIZE)); 144 if (buf == NULL) 145 return(0); 146 slaves[i].tblock = (char (*)[TP_BSIZE]) 147 (((long)&buf[ntrec + 1] + pgoff) &~ pgoff); 148 slaves[i].req = (struct req *)slaves[i].tblock - ntrec - 1; 149 } 150 slp = &slaves[0]; 151 slp->count = 1; 152 slp->tapea = 0; 153 slp->firstrec = 0; 154 nextblock = slp->tblock; 155 return(1); 156 } 157 158 void 159 writerec(char *dp, int isspcl) 160 { 161 162 slp->req[trecno].dblk = 0; 163 slp->req[trecno].count = 1; 164 *(union u_spcl *)(*(nextblock)++) = *(union u_spcl *)dp; 165 if (isspcl) 166 lastspclrec = spcl.c_tapea; 167 trecno++; 168 spcl.c_tapea++; 169 if (trecno >= ntrec) 170 flushtape(); 171 } 172 173 void 174 dumpblock(daddr_t blkno, int size) 175 { 176 int avail, tpblks; 177 daddr_t dblkno; 178 179 dblkno = fsbtodb(sblock, blkno); 180 tpblks = size >> tp_bshift; 181 while ((avail = MINIMUM(tpblks, ntrec - trecno)) > 0) { 182 slp->req[trecno].dblk = dblkno; 183 slp->req[trecno].count = avail; 184 trecno += avail; 185 spcl.c_tapea += avail; 186 if (trecno >= ntrec) 187 flushtape(); 188 dblkno += avail << (tp_bshift - (ffs(DEV_BSIZE) - 1)); 189 tpblks -= avail; 190 } 191 } 192 193 int nogripe = 0; 194 195 void 196 tperror(int signo) 197 { 198 /* XXX - signal races */ 199 200 if (pipeout) { 201 msg("write error on %s\n", tape); 202 quit("Cannot recover\n"); 203 /* NOTREACHED */ 204 } 205 msg("write error %lld blocks into volume %d\n", 206 (long long)blocksthisvol, tapeno); 207 broadcast("DUMP WRITE ERROR!\n"); 208 if (!query("Do you want to restart?")) 209 dumpabort(0); 210 msg("Closing this volume. Prepare to restart with new media;\n"); 211 msg("this dump volume will be rewritten.\n"); 212 killall(); 213 nogripe = 1; 214 close_rewind(); 215 Exit(X_REWRITE); 216 } 217 218 void 219 sigpipe(int signo) 220 { 221 222 quit("Broken pipe\n"); 223 } 224 225 /* 226 * do_stats -- 227 * Update xferrate stats 228 */ 229 time_t 230 do_stats(void) 231 { 232 time_t tnow, ttaken; 233 int64_t blocks; 234 235 (void)time(&tnow); 236 ttaken = tnow - tstart_volume; 237 blocks = spcl.c_tapea - tapea_volume; 238 msg("Volume %d completed at: %s", tapeno, ctime(&tnow)); 239 if (ttaken > 0) { 240 msg("Volume %d took %lld:%02lld:%02lld\n", tapeno, 241 (long long)ttaken / 3600, ((long long)ttaken % 3600) / 60, 242 (long long)ttaken % 60); 243 blocks /= ttaken; 244 msg("Volume %d transfer rate: %lld KB/s\n", tapeno, blocks); 245 xferrate += blocks; 246 } 247 return(tnow); 248 } 249 250 /* 251 * statussig -- 252 * information message upon receipt of SIGINFO 253 * (derived from optr.c::timeest()) 254 * XXX not safe 255 */ 256 void 257 statussig(int signo) 258 { 259 time_t tnow, deltat; 260 int save_errno = errno; 261 262 if (blockswritten < 500) 263 return; 264 (void) time(&tnow); 265 deltat = tstart_writing - tnow + (1.0 * (tnow - tstart_writing)) 266 / blockswritten * tapesize; 267 /* XXX not safe due to floating point printf */ 268 dprintf(STDERR_FILENO, 269 "dump: %s %3.2f%% done at %lld KB/s, finished in %d:%02d\n", 270 tape, (blockswritten * 100.0) / tapesize, 271 (spcl.c_tapea - tapea_volume) / (tnow - tstart_volume), 272 (int)(deltat / 3600), (int)((deltat % 3600) / 60)); 273 errno = save_errno; 274 } 275 276 static void 277 flushtape(void) 278 { 279 int i, blks, got; 280 int64_t lastfirstrec; 281 282 int siz = (char *)nextblock - (char *)slp->req; 283 284 slp->req[trecno].count = 0; /* Sentinel */ 285 286 if (atomic((ssize_t (*)(int, void *, size_t))write, slp->fd, 287 (char *)slp->req, siz) != siz) 288 quit("error writing command pipe: %s\n", strerror(errno)); 289 slp->sent = 1; /* we sent a request, read the response later */ 290 291 lastfirstrec = slp->firstrec; 292 293 if (++slp >= &slaves[SLAVES]) 294 slp = &slaves[0]; 295 296 /* Read results back from next slave */ 297 if (slp->sent) { 298 if (atomic(read, slp->fd, (char *)&got, sizeof(got)) 299 != sizeof(got)) { 300 perror(" DUMP: error reading command pipe in master"); 301 dumpabort(0); 302 } 303 slp->sent = 0; 304 305 /* Check for end of tape */ 306 if (got < writesize) { 307 msg("End of tape detected\n"); 308 309 /* 310 * Drain the results, don't care what the values were. 311 * If we read them here then trewind won't... 312 */ 313 for (i = 0; i < SLAVES; i++) { 314 if (slaves[i].sent) { 315 if (atomic(read, slaves[i].fd, 316 (char *)&got, sizeof(got)) 317 != sizeof(got)) { 318 perror(" DUMP: error reading command pipe in master"); 319 dumpabort(0); 320 } 321 slaves[i].sent = 0; 322 } 323 } 324 325 close_rewind(); 326 rollforward(); 327 return; 328 } 329 } 330 331 blks = 0; 332 if (spcl.c_type != TS_END && spcl.c_type != TS_CLRI && 333 spcl.c_type != TS_BITS) { 334 if (spcl.c_count > TP_NINDIR) 335 quit("c_count too large\n"); 336 for (i = 0; i < spcl.c_count; i++) 337 if (spcl.c_addr[i] != 0) 338 blks++; 339 } 340 slp->count = lastspclrec + blks + 1 - spcl.c_tapea; 341 slp->tapea = spcl.c_tapea; 342 slp->firstrec = lastfirstrec + ntrec; 343 slp->inode = curino; 344 nextblock = slp->tblock; 345 trecno = 0; 346 asize += tenths; 347 blockswritten += ntrec; 348 blocksthisvol += ntrec; 349 if (!pipeout && !unlimited && (blocksperfile ? 350 (blocksthisvol >= blocksperfile) : (asize > tsize))) { 351 close_rewind(); 352 startnewtape(0); 353 } 354 timeest(); 355 } 356 357 void 358 trewind(void) 359 { 360 struct stat sb; 361 int f, got; 362 363 for (f = 0; f < SLAVES; f++) { 364 /* 365 * Drain the results, but unlike EOT we DO (or should) care 366 * what the return values were, since if we detect EOT after 367 * we think we've written the last blocks to the tape anyway, 368 * we have to replay those blocks with rollforward. 369 * 370 * fixme: punt for now. 371 */ 372 if (slaves[f].sent) { 373 if (atomic(read, slaves[f].fd, (char *)&got, sizeof(got)) 374 != sizeof(got)) { 375 perror(" DUMP: error reading command pipe in master"); 376 dumpabort(0); 377 } 378 slaves[f].sent = 0; 379 if (got != writesize) { 380 msg("EOT detected in last 2 tape records!\n"); 381 msg("Use a longer tape, decrease the size estimate\n"); 382 quit("or use no size estimate at all.\n"); 383 } 384 } 385 (void) close(slaves[f].fd); 386 } 387 while (wait((int *)NULL) >= 0) /* wait for any signals from slaves */ 388 /* void */; 389 390 if (pipeout) 391 return; 392 393 msg("Closing %s\n", tape); 394 395 #ifdef RDUMP 396 if (host) { 397 rmtclose(); 398 while (rmtopen(tape, O_RDONLY) < 0) 399 sleep(10); 400 rmtclose(); 401 return; 402 } 403 #endif 404 /* 405 * st(4) says: "Bit 1 of the minor number specifies whether an eject is 406 * attempted when the device is closed. When it is set, the device 407 * will attempt to eject its media on close ...". 408 * 409 * If the tape has been ejected, looping on open() will generate 'Media 410 * not present' errors until a tape is loaded. Once loaded the tape 411 * will be immediately ejected as a result of the second close(). 412 * 413 * So if the tape will be ejected, just close and return. 414 */ 415 if ((fstat(tapefd, &sb) == 0) && (minor(sb.st_rdev) & 0x02)) { 416 (void) close(tapefd); 417 return; 418 } 419 420 (void) close(tapefd); 421 while ((f = open(tape, O_RDONLY)) == -1) 422 sleep (10); 423 (void) close(f); 424 } 425 426 void 427 close_rewind(void) 428 { 429 trewind(); 430 (void)do_stats(); 431 if (nexttape) 432 return; 433 if (!nogripe) { 434 msg("Change Volumes: Mount volume #%d\n", tapeno+1); 435 broadcast("CHANGE DUMP VOLUMES!\7\7\n"); 436 } 437 while (!query("Is the new volume mounted and ready to go?")) 438 if (query("Do you want to abort?")) { 439 dumpabort(0); 440 /*NOTREACHED*/ 441 } 442 } 443 444 void 445 rollforward(void) 446 { 447 struct req *p, *q, *prev; 448 struct slave *tslp; 449 int i, size, got; 450 int64_t savedtapea; 451 union u_spcl *ntb, *otb; 452 tslp = &slaves[SLAVES]; 453 ntb = (union u_spcl *)tslp->tblock[1]; 454 455 /* 456 * Each of the N slaves should have requests that need to 457 * be replayed on the next tape. Use the extra slave buffers 458 * (slaves[SLAVES]) to construct request lists to be sent to 459 * each slave in turn. 460 */ 461 for (i = 0; i < SLAVES; i++) { 462 q = &tslp->req[1]; 463 otb = (union u_spcl *)slp->tblock; 464 465 /* 466 * For each request in the current slave, copy it to tslp. 467 */ 468 469 prev = NULL; 470 for (p = slp->req; p->count > 0; p += p->count) { 471 *q = *p; 472 if (p->dblk == 0) 473 *ntb++ = *otb++; /* copy the datablock also */ 474 prev = q; 475 q += q->count; 476 } 477 if (prev == NULL) 478 quit("rollforward: protocol botch\n"); 479 if (prev->dblk != 0) 480 prev->count -= 1; 481 else 482 ntb--; 483 q -= 1; 484 q->count = 0; 485 q = &tslp->req[0]; 486 if (i == 0) { 487 q->dblk = 0; 488 q->count = 1; 489 trecno = 0; 490 nextblock = tslp->tblock; 491 savedtapea = spcl.c_tapea; 492 spcl.c_tapea = slp->tapea; 493 startnewtape(0); 494 spcl.c_tapea = savedtapea; 495 lastspclrec = savedtapea - 1; 496 } 497 size = (char *)ntb - (char *)q; 498 if (atomic((ssize_t (*)(int, void *, size_t))write, 499 slp->fd, (char *)q, size) != size) { 500 perror(" DUMP: error writing command pipe"); 501 dumpabort(0); 502 } 503 slp->sent = 1; 504 if (++slp >= &slaves[SLAVES]) 505 slp = &slaves[0]; 506 507 q->count = 1; 508 509 if (prev->dblk != 0) { 510 /* 511 * If the last one was a disk block, make the 512 * first of this one be the last bit of that disk 513 * block... 514 */ 515 q->dblk = prev->dblk + 516 prev->count * (TP_BSIZE / DEV_BSIZE); 517 ntb = (union u_spcl *)tslp->tblock; 518 } else { 519 /* 520 * It wasn't a disk block. Copy the data to its 521 * new location in the buffer. 522 */ 523 q->dblk = 0; 524 *((union u_spcl *)tslp->tblock) = *ntb; 525 ntb = (union u_spcl *)tslp->tblock[1]; 526 } 527 } 528 slp->req[0] = *q; 529 nextblock = slp->tblock; 530 if (q->dblk == 0) 531 nextblock++; 532 trecno = 1; 533 534 /* 535 * Clear the first slaves' response. One hopes that it 536 * worked ok, otherwise the tape is much too short! 537 */ 538 if (slp->sent) { 539 if (atomic(read, slp->fd, (char *)&got, sizeof(got)) 540 != sizeof(got)) { 541 perror(" DUMP: error reading command pipe in master"); 542 dumpabort(0); 543 } 544 slp->sent = 0; 545 546 if (got != writesize) { 547 quit("EOT detected at start of the tape!\n"); 548 } 549 } 550 } 551 552 /* 553 * We implement taking and restoring checkpoints on the tape level. 554 * When each tape is opened, a new process is created by forking; this 555 * saves all of the necessary context in the parent. The child 556 * continues the dump; the parent waits around, saving the context. 557 * If the child returns X_REWRITE, then it had problems writing that tape; 558 * this causes the parent to fork again, duplicating the context, and 559 * everything continues as if nothing had happened. 560 */ 561 void 562 startnewtape(int top) 563 { 564 pid_t parentpid; 565 pid_t childpid; 566 int status; 567 pid_t waitingpid; 568 char *p; 569 sig_t interrupt_save; 570 571 interrupt_save = signal(SIGINT, SIG_IGN); 572 parentpid = getpid(); 573 tapea_volume = spcl.c_tapea; 574 (void)time(&tstart_volume); 575 576 restore_check_point: 577 (void)signal(SIGINT, interrupt_save); 578 /* 579 * All signals are inherited... 580 */ 581 childpid = fork(); 582 if (childpid == -1) { 583 msg("Context save fork fails in parent %d\n", parentpid); 584 Exit(X_ABORT); 585 } 586 if (childpid != 0) { 587 /* 588 * PARENT: 589 * save the context by waiting 590 * until the child doing all of the work returns. 591 * don't catch the interrupt 592 */ 593 signal(SIGINT, SIG_IGN); 594 #ifdef TDEBUG 595 msg("Tape: %d; parent process: %d child process %d\n", 596 tapeno+1, parentpid, childpid); 597 #endif /* TDEBUG */ 598 while ((waitingpid = wait(&status)) != childpid) 599 msg("Parent %d waiting for child %d has another child %d return\n", 600 parentpid, childpid, waitingpid); 601 if (status & 0xFF) { 602 msg("Child %d returns LOB status %o\n", 603 childpid, status&0xFF); 604 } 605 status = (status >> 8) & 0xFF; 606 #ifdef TDEBUG 607 switch(status) { 608 case X_FINOK: 609 msg("Child %d finishes X_FINOK\n", childpid); 610 break; 611 case X_ABORT: 612 msg("Child %d finishes X_ABORT\n", childpid); 613 break; 614 case X_REWRITE: 615 msg("Child %d finishes X_REWRITE\n", childpid); 616 break; 617 default: 618 msg("Child %d finishes unknown %d\n", 619 childpid, status); 620 break; 621 } 622 #endif /* TDEBUG */ 623 switch(status) { 624 case X_FINOK: 625 Exit(X_FINOK); 626 break; 627 case X_ABORT: 628 Exit(X_ABORT); 629 break; 630 case X_REWRITE: 631 goto restore_check_point; 632 default: 633 msg("Bad return code from dump: %d\n", status); 634 Exit(X_ABORT); 635 } 636 /*NOTREACHED*/ 637 } else { /* we are the child; just continue */ 638 #ifdef TDEBUG 639 sleep(4); /* allow time for parent's message to get out */ 640 msg("Child on Tape %d has parent %d, my pid = %d\n", 641 tapeno+1, parentpid, getpid()); 642 #endif /* TDEBUG */ 643 /* 644 * If we have a name like "/dev/rst0,/dev/rst1", 645 * use the name before the comma first, and save 646 * the remaining names for subsequent volumes. 647 */ 648 tapeno++; /* current tape sequence */ 649 if (nexttape || strchr(tape, ',')) { 650 if (nexttape && *nexttape) 651 tape = nexttape; 652 if ((p = strchr(tape, ',')) != NULL) { 653 *p = '\0'; 654 nexttape = p + 1; 655 } else 656 nexttape = NULL; 657 msg("Dumping volume %d on %s\n", tapeno, tape); 658 } 659 #ifdef RDUMP 660 while ((tapefd = (host ? rmtopen(tape, O_WRONLY|O_CREAT) : 661 pipeout ? 1 : open(tape, O_WRONLY|O_CREAT, 0666))) == -1) 662 #else 663 while ((tapefd = (pipeout ? 1 : 664 open(tape, O_WRONLY|O_CREAT, 0666))) == -1) 665 #endif 666 { 667 msg("Cannot open output \"%s\".\n", tape); 668 if (!query("Do you want to retry the open?")) 669 dumpabort(0); 670 } 671 672 enslave(); /* Share open tape file descriptor with slaves */ 673 674 asize = 0; 675 blocksthisvol = 0; 676 if (top) 677 newtape++; /* new tape signal */ 678 spcl.c_count = slp->count; 679 /* 680 * measure firstrec in TP_BSIZE units since restore doesn't 681 * know the correct ntrec value... 682 */ 683 spcl.c_firstrec = slp->firstrec; 684 spcl.c_volume++; 685 spcl.c_type = TS_TAPE; 686 if (sblock->fs_magic != FS_UFS2_MAGIC) 687 spcl.c_flags |= DR_NEWHEADER; 688 writeheader((ino_t)slp->inode); 689 if (sblock->fs_magic != FS_UFS2_MAGIC) 690 spcl.c_flags &=~ DR_NEWHEADER; 691 msg("Volume %d started at: %s", tapeno, ctime(&tstart_volume)); 692 if (tapeno > 1) 693 msg("Volume %d begins with blocks from inode %llu\n", 694 tapeno, (unsigned long long)slp->inode); 695 } 696 } 697 698 void 699 dumpabort(int signo) 700 { 701 702 if (master != 0 && master != getpid()) 703 /* Signals master to call dumpabort */ 704 (void) kill(master, SIGTERM); 705 else { 706 killall(); 707 msg("The ENTIRE dump is aborted.\n"); 708 } 709 #ifdef RDUMP 710 rmtclose(); 711 #endif 712 Exit(X_ABORT); 713 } 714 715 __dead void 716 Exit(int status) 717 { 718 719 #ifdef TDEBUG 720 msg("pid = %d exits with status %d\n", getpid(), status); 721 #endif /* TDEBUG */ 722 exit(status); 723 } 724 725 /* 726 * proceed - handler for SIGUSR2, used to synchronize IO between the slaves. 727 */ 728 void 729 proceed(int signo) 730 { 731 caught++; 732 } 733 734 void 735 enslave(void) 736 { 737 int cmd[2]; 738 int i, j; 739 740 master = getpid(); 741 742 signal(SIGTERM, dumpabort); /* Slave sends SIGTERM on dumpabort() */ 743 signal(SIGPIPE, sigpipe); 744 signal(SIGUSR1, tperror); /* Slave sends SIGUSR1 on tape errors */ 745 signal(SIGUSR2, proceed); /* Slave sends SIGUSR2 to next slave */ 746 747 for (i = 0; i < SLAVES; i++) { 748 if (i == slp - &slaves[0]) { 749 caught = 1; 750 } else { 751 caught = 0; 752 } 753 754 if (socketpair(AF_UNIX, SOCK_STREAM, 0, cmd) == -1 || 755 (slaves[i].pid = fork()) == -1) 756 quit("too many slaves, %d (recompile smaller): %s\n", 757 i, strerror(errno)); 758 759 slaves[i].fd = cmd[1]; 760 slaves[i].sent = 0; 761 if (slaves[i].pid == 0) { /* Slave starts up here */ 762 for (j = 0; j <= i; j++) 763 (void) close(slaves[j].fd); 764 signal(SIGINT, SIG_IGN); /* Master handles this */ 765 signal(SIGINFO, SIG_IGN); 766 doslave(cmd[0], i); 767 Exit(X_FINOK); 768 } 769 } 770 771 for (i = 0; i < SLAVES; i++) 772 (void) atomic((ssize_t (*)(int, void *, size_t))write, 773 slaves[i].fd, (char *) &slaves[(i + 1) % SLAVES].pid, 774 sizeof(slaves[0].pid)); 775 master = 0; 776 } 777 778 void 779 killall(void) 780 { 781 int i; 782 783 for (i = 0; i < SLAVES; i++) 784 if (slaves[i].pid > 0) { 785 (void) kill(slaves[i].pid, SIGKILL); 786 slaves[i].pid = 0; 787 } 788 } 789 790 /* 791 * Synchronization - each process has a lockfile, and shares file 792 * descriptors to the following process's lockfile. When our write 793 * completes, we release our lock on the following process's lock- 794 * file, allowing the following process to lock it and proceed. We 795 * get the lock back for the next cycle by swapping descriptors. 796 */ 797 static void 798 doslave(int cmd, int slave_number) 799 { 800 int nread, nextslave, size, wrote = 0, eot_count; 801 sigset_t nsigset, osigset; 802 803 /* 804 * Need our own seek pointer. 805 */ 806 (void) close(diskfd); 807 if ((diskfd = open(disk, O_RDONLY)) == -1) 808 quit("slave couldn't reopen disk: %s\n", strerror(errno)); 809 810 /* 811 * Need the pid of the next slave in the loop... 812 */ 813 if ((nread = atomic(read, cmd, (char *)&nextslave, sizeof(nextslave))) 814 != sizeof(nextslave)) { 815 quit("master/slave protocol botched - didn't get pid of next slave.\n"); 816 } 817 818 /* 819 * Get list of blocks to dump, read the blocks into tape buffer 820 */ 821 while ((nread = atomic(read, cmd, (char *)slp->req, reqsiz)) == reqsiz) { 822 struct req *p = slp->req; 823 824 for (trecno = 0; trecno < ntrec; 825 trecno += p->count, p += p->count) { 826 if (p->dblk) { 827 bread(p->dblk, slp->tblock[trecno], 828 p->count * TP_BSIZE); 829 } else { 830 if (p->count != 1 || atomic(read, cmd, 831 (char *)slp->tblock[trecno], 832 TP_BSIZE) != TP_BSIZE) 833 quit("master/slave protocol botched.\n"); 834 } 835 } 836 837 sigemptyset(&nsigset); 838 sigaddset(&nsigset, SIGUSR2); 839 sigprocmask(SIG_BLOCK, &nsigset, &osigset); 840 while (!caught) 841 sigsuspend(&osigset); 842 caught = 0; 843 sigprocmask(SIG_SETMASK, &osigset, NULL); 844 845 /* Try to write the data... */ 846 eot_count = 0; 847 size = 0; 848 849 while (eot_count < 10 && size < writesize) { 850 #ifdef RDUMP 851 if (host) 852 wrote = rmtwrite(slp->tblock[0]+size, 853 writesize-size); 854 else 855 #endif 856 wrote = write(tapefd, slp->tblock[0]+size, 857 writesize-size); 858 #ifdef WRITEDEBUG 859 printf("slave %d wrote %d\n", slave_number, wrote); 860 #endif 861 if (wrote < 0) 862 break; 863 if (wrote == 0) 864 eot_count++; 865 size += wrote; 866 } 867 868 #ifdef WRITEDEBUG 869 if (size != writesize) 870 printf("slave %d only wrote %d out of %d bytes and gave up.\n", 871 slave_number, size, writesize); 872 #endif 873 874 if (eot_count > 0) 875 size = 0; 876 877 /* 878 * Handle ENOSPC as an EOT condition 879 */ 880 if (wrote < 0 && errno == ENOSPC) { 881 wrote = 0; 882 eot_count++; 883 } 884 885 if (size < 0) { 886 (void) kill(master, SIGUSR1); 887 sigemptyset(&nsigset); 888 for (;;) 889 sigsuspend(&nsigset); 890 } else { 891 /* 892 * pass size of write back to master 893 * (for EOT handling) 894 */ 895 (void) atomic((ssize_t (*)(int, void *, size_t))write, 896 cmd, (char *)&size, sizeof(size)); 897 } 898 899 /* 900 * If partial write, don't want next slave to go. 901 * Also jolts him awake. 902 */ 903 (void) kill(nextslave, SIGUSR2); 904 } 905 if (nread != 0) 906 quit("error reading command pipe: %s\n", strerror(errno)); 907 } 908 909 /* 910 * Since a read from a pipe may not return all we asked for, 911 * or a write may not write all we ask if we get a signal, 912 * loop until the count is satisfied (or error). 913 */ 914 static ssize_t 915 atomic(ssize_t (*func)(int, void *, size_t), int fd, char *buf, int count) 916 { 917 ssize_t got, need = count; 918 919 while ((got = (*func)(fd, buf, need)) > 0 && (need -= got) > 0) 920 buf += got; 921 return (got < 0 ? got : count - need); 922 } 923