1 /*- 2 * Copyright (c) 1992 Keith Muller. 3 * Copyright (c) 1992, 1993 4 * The Regents of the University of California. All rights reserved. 5 * 6 * This code is derived from software contributed to Berkeley by 7 * Keith Muller of the University of California, San Diego. 8 * 9 * %sccs.include.redist.c% 10 */ 11 12 #ifndef lint 13 static char sccsid[] = "@(#)ar_io.c 8.2 (Berkeley) 04/18/94"; 14 #endif /* not lint */ 15 16 #include <sys/types.h> 17 #include <sys/time.h> 18 #include <sys/stat.h> 19 #include <sys/ioctl.h> 20 #include <sys/mtio.h> 21 #include <sys/param.h> 22 #include <signal.h> 23 #include <string.h> 24 #include <fcntl.h> 25 #include <unistd.h> 26 #include <stdio.h> 27 #include <ctype.h> 28 #include <errno.h> 29 #include <stdlib.h> 30 #include "pax.h" 31 #include "extern.h" 32 33 /* 34 * Routines which deal directly with the archive I/O device/file. 35 */ 36 37 #define DMOD 0666 /* default mode of created archives */ 38 #define EXT_MODE O_RDONLY /* open mode for list/extract */ 39 #define AR_MODE (O_WRONLY | O_CREAT | O_TRUNC) /* mode for archive */ 40 #define APP_MODE O_RDWR /* mode for append */ 41 #define STDO "<STDOUT>" /* psuedo name for stdout */ 42 #define STDN "<STDIN>" /* psuedo name for stdin */ 43 static int arfd = -1; /* archive file descriptor */ 44 static int artyp = ISREG; /* archive type: file/FIFO/tape */ 45 static int arvol = 1; /* archive volume number */ 46 static int lstrval = -1; /* return value from last i/o */ 47 static int io_ok; /* i/o worked on volume after resync */ 48 static int did_io; /* did i/o ever occur on volume? */ 49 static int done; /* set via tty termination */ 50 static struct stat arsb; /* stat of archive device at open */ 51 static int invld_rec; /* tape has out of spec record size */ 52 static int wr_trail = 1; /* trailer was rewritten in append */ 53 static int can_unlnk = 0; /* do we unlink null archives? */ 54 char *arcname; /* printable name of archive */ 55 56 static int get_phys __P((void)); 57 extern sigset_t s_mask; 58 59 /* 60 * ar_open() 61 * Opens the next archive volume. Determines the type of the device and 62 * sets up block sizes as required by the archive device and the format. 63 * Note: we may be called with name == NULL on the first open only. 64 * Return: 65 * -1 on failure, 0 otherwise 66 */ 67 68 #if __STDC__ 69 int 70 ar_open(char *name) 71 #else 72 int 73 ar_open(name) 74 char *name; 75 #endif 76 { 77 struct mtget mb; 78 79 if (arfd != -1) 80 (void)close(arfd); 81 arfd = -1; 82 can_unlnk = did_io = io_ok = invld_rec = 0; 83 artyp = ISREG; 84 flcnt = 0; 85 86 /* 87 * open based on overall operation mode 88 */ 89 switch (act) { 90 case LIST: 91 case EXTRACT: 92 if (name == NULL) { 93 arfd = STDIN_FILENO; 94 arcname = STDN; 95 } else if ((arfd = open(name, EXT_MODE, DMOD)) < 0) 96 syswarn(0, errno, "Failed open to read on %s", name); 97 break; 98 case ARCHIVE: 99 if (name == NULL) { 100 arfd = STDOUT_FILENO; 101 arcname = STDO; 102 } else if ((arfd = open(name, AR_MODE, DMOD)) < 0) 103 syswarn(0, errno, "Failed open to write on %s", name); 104 else 105 can_unlnk = 1; 106 break; 107 case APPND: 108 if (name == NULL) { 109 arfd = STDOUT_FILENO; 110 arcname = STDO; 111 } else if ((arfd = open(name, APP_MODE, DMOD)) < 0) 112 syswarn(0, errno, "Failed open to read/write on %s", 113 name); 114 break; 115 case COPY: 116 /* 117 * arfd not used in COPY mode 118 */ 119 arcname = "<NONE>"; 120 lstrval = 1; 121 return(0); 122 } 123 if (arfd < 0) 124 return(-1); 125 126 /* 127 * set up is based on device type 128 */ 129 if (fstat(arfd, &arsb) < 0) { 130 syswarn(0, errno, "Failed stat on %s", arcname); 131 (void)close(arfd); 132 arfd = -1; 133 can_unlnk = 0; 134 return(-1); 135 } 136 if (S_ISDIR(arsb.st_mode)) { 137 warn(0, "Cannot write an archive on top of a directory %s", 138 arcname); 139 (void)close(arfd); 140 arfd = -1; 141 can_unlnk = 0; 142 return(-1); 143 } 144 145 if (S_ISCHR(arsb.st_mode)) 146 artyp = ioctl(arfd, MTIOCGET, &mb) ? ISCHR : ISTAPE; 147 else if (S_ISBLK(arsb.st_mode)) 148 artyp = ISBLK; 149 else if ((lseek(arfd, (off_t)0L, SEEK_CUR) == -1) && (errno == ESPIPE)) 150 artyp = ISPIPE; 151 else 152 artyp = ISREG; 153 154 /* 155 * make sure we beyond any doubt that we only can unlink regular files 156 * we created 157 */ 158 if (artyp != ISREG) 159 can_unlnk = 0; 160 /* 161 * if we are writing, we are done 162 */ 163 if (act == ARCHIVE) { 164 blksz = rdblksz = wrblksz; 165 lstrval = 1; 166 return(0); 167 } 168 169 /* 170 * set default blksz on read. APPNDs writes rdblksz on the last volume 171 * On all new archive volumes, we shift to wrblksz (if the user 172 * specified one, otherwize we will continue to use rdblksz). We 173 * must to set blocksize based on what kind of device the archive is 174 * stored. 175 */ 176 switch(artyp) { 177 case ISTAPE: 178 /* 179 * Tape drives come in at least two flavors. Those that support 180 * variable sized records and those that have fixed sized 181 * records. They must be treated differently. For tape drives 182 * that support variable sized records, we must make large 183 * reads to make sure we get the entire record, otherwise we 184 * will just get the first part of the record (up to size we 185 * asked). Tapes with fixed sized records may or may not return 186 * multiple records in a single read. We really do not care 187 * what the physical record size is UNLESS we are going to 188 * append. (We will need the physical block size to rewrite 189 * the trailer). Only when we are appending do we go to the 190 * effort to figure out the true PHYSICAL record size. 191 */ 192 blksz = rdblksz = MAXBLK; 193 break; 194 case ISPIPE: 195 case ISBLK: 196 case ISCHR: 197 /* 198 * Blocksize is not a major issue with these devices (but must 199 * be kept a multiple of 512). If the user specified a write 200 * block size, we use that to read. Under append, we must 201 * always keep blksz == rdblksz. Otherwise we go ahead and use 202 * the device optimal blocksize as (and if) returned by stat 203 * and if it is within pax specs. 204 */ 205 if ((act == APPND) && wrblksz) { 206 blksz = rdblksz = wrblksz; 207 break; 208 } 209 210 if ((arsb.st_blksize > 0) && (arsb.st_blksize < MAXBLK) && 211 ((arsb.st_blksize % BLKMULT) == 0)) 212 rdblksz = arsb.st_blksize; 213 else 214 rdblksz = DEVBLK; 215 /* 216 * For performance go for large reads when we can without harm 217 */ 218 if ((act == APPND) || (artyp == ISCHR)) 219 blksz = rdblksz; 220 else 221 blksz = MAXBLK; 222 break; 223 case ISREG: 224 /* 225 * if the user specified wrblksz works, use it. Under appends 226 * we must always keep blksz == rdblksz 227 */ 228 if ((act == APPND) && wrblksz && ((arsb.st_size%wrblksz)==0)){ 229 blksz = rdblksz = wrblksz; 230 break; 231 } 232 /* 233 * See if we can find the blocking factor from the file size 234 */ 235 for (rdblksz = MAXBLK; rdblksz > 0; rdblksz -= BLKMULT) 236 if ((arsb.st_size % rdblksz) == 0) 237 break; 238 /* 239 * When we cannont find a match, we may have a flawed archive. 240 */ 241 if (rdblksz <= 0) 242 rdblksz = FILEBLK; 243 /* 244 * for performance go for large reads when we can 245 */ 246 if (act == APPND) 247 blksz = rdblksz; 248 else 249 blksz = MAXBLK; 250 break; 251 default: 252 /* 253 * should never happen, worse case, slow... 254 */ 255 blksz = rdblksz = BLKMULT; 256 break; 257 } 258 lstrval = 1; 259 return(0); 260 } 261 262 /* 263 * ar_close() 264 * closes archive device, increments volume number, and prints i/o summary 265 */ 266 #if __STDC__ 267 void 268 ar_close(void) 269 #else 270 void 271 ar_close() 272 #endif 273 { 274 FILE *outf; 275 276 if (arfd < 0) { 277 did_io = io_ok = flcnt = 0; 278 return; 279 } 280 281 if (act == LIST) 282 outf = stdout; 283 else 284 outf = stderr; 285 286 /* 287 * Close archive file. This may take a LONG while on tapes (we may be 288 * forced to wait for the rewind to complete) so tell the user what is 289 * going on (this avoids the user hitting control-c thinking pax is 290 * broken). 291 */ 292 if (vflag && (artyp == ISTAPE)) { 293 if (vfpart) 294 (void)putc('\n', outf); 295 (void)fprintf(outf, 296 "%s: Waiting for tape drive close to complete...", 297 argv0); 298 (void)fflush(outf); 299 } 300 301 /* 302 * if nothing was written to the archive (and we created it), we remove 303 * it 304 */ 305 if (can_unlnk && (fstat(arfd, &arsb) == 0) && (S_ISREG(arsb.st_mode)) && 306 (arsb.st_size == 0)) { 307 (void)unlink(arcname); 308 can_unlnk = 0; 309 } 310 311 (void)close(arfd); 312 313 if (vflag && (artyp == ISTAPE)) { 314 (void)fputs("done.\n", outf); 315 vfpart = 0; 316 (void)fflush(outf); 317 } 318 arfd = -1; 319 320 if (!io_ok && !did_io) { 321 flcnt = 0; 322 return; 323 } 324 did_io = io_ok = 0; 325 326 /* 327 * The volume number is only increased when the last device has data 328 * and we have already determined the archive format. 329 */ 330 if (frmt != NULL) 331 ++arvol; 332 333 if (!vflag) { 334 flcnt = 0; 335 return; 336 } 337 338 /* 339 * Print out a summary of I/O for this archive volume. 340 */ 341 if (vfpart) { 342 (void)putc('\n', outf); 343 vfpart = 0; 344 } 345 346 /* 347 * If we have not determined the format yet, we just say how many bytes 348 * we have skipped over looking for a header to id. there is no way we 349 * could have written anything yet. 350 */ 351 if (frmt == NULL) { 352 # ifdef NET2_STAT 353 (void)fprintf(outf, "%s: unknown format, %lu bytes skipped.\n", 354 # else 355 (void)fprintf(outf, "%s: unknown format, %qu bytes skipped.\n", 356 # endif 357 argv0, rdcnt); 358 (void)fflush(outf); 359 flcnt = 0; 360 return; 361 } 362 363 (void)fprintf(outf, 364 # ifdef NET2_STAT 365 "%s: %s vol %d, %lu files, %lu bytes read, %lu bytes written.\n", 366 # else 367 "%s: %s vol %d, %lu files, %qu bytes read, %qu bytes written.\n", 368 # endif 369 argv0, frmt->name, arvol-1, flcnt, rdcnt, wrcnt); 370 (void)fflush(outf); 371 flcnt = 0; 372 } 373 374 /* 375 * ar_drain() 376 * drain any archive format independent padding from an archive read 377 * from a socket or a pipe. This is to prevent the process on the 378 * other side of the pipe from getting a SIGPIPE (pax will stop 379 * reading an archive once a format dependent trailer is detected). 380 */ 381 #if __STDC__ 382 void 383 ar_drain(void) 384 #else 385 void 386 ar_drain() 387 #endif 388 { 389 register int res; 390 char drbuf[MAXBLK]; 391 392 /* 393 * we only drain from a pipe/socket. Other devices can be closed 394 * without reading up to end of file. We sure hope that pipe is closed 395 * on the other side so we will get an EOF. 396 */ 397 if ((artyp != ISPIPE) || (lstrval <= 0)) 398 return; 399 400 /* 401 * keep reading until pipe is drained 402 */ 403 while ((res = read(arfd, drbuf, sizeof(drbuf))) > 0) 404 ; 405 lstrval = res; 406 } 407 408 /* 409 * ar_set_wr() 410 * Set up device right before switching from read to write in an append. 411 * device dependent code (if required) to do this should be added here. 412 * For all archive devices we are already positioned at the place we want 413 * to start writing when this routine is called. 414 * Return: 415 * 0 if all ready to write, -1 otherwise 416 */ 417 418 #if __STDC__ 419 int 420 ar_set_wr(void) 421 #else 422 int 423 ar_set_wr() 424 #endif 425 { 426 off_t cpos; 427 428 /* 429 * we must make sure the trailer is rewritten on append, ar_next() 430 * will stop us if the archive containing the trailer was not written 431 */ 432 wr_trail = 0; 433 434 /* 435 * Add any device dependent code as required here 436 */ 437 if (artyp != ISREG) 438 return(0); 439 /* 440 * Ok we have an archive in a regular file. If we were rewriting a 441 * file, we must get rid of all the stuff after the current offset 442 * (it was not written by pax). 443 */ 444 if (((cpos = lseek(arfd, (off_t)0L, SEEK_CUR)) < 0) || 445 (ftruncate(arfd, cpos) < 0)) { 446 syswarn(1, errno, "Unable to truncate archive file"); 447 return(-1); 448 } 449 return(0); 450 } 451 452 /* 453 * ar_app_ok() 454 * check if the last volume in the archive allows appends. We cannot check 455 * this until we are ready to write since there is no spec that says all 456 * volumes in a single archive have to be of the same type... 457 * Return: 458 * 0 if we can append, -1 otherwise. 459 */ 460 461 #if __STDC__ 462 int 463 ar_app_ok(void) 464 #else 465 int 466 ar_app_ok() 467 #endif 468 { 469 if (artyp == ISPIPE) { 470 warn(1, "Cannot append to an archive obtained from a pipe."); 471 return(-1); 472 } 473 474 if (!invld_rec) 475 return(0); 476 warn(1,"Cannot append, device record size %d does not support %s spec", 477 rdblksz, argv0); 478 return(-1); 479 } 480 481 /* 482 * ar_read() 483 * read up to a specified number of bytes from the archive into the 484 * supplied buffer. When dealing with tapes we may not always be able to 485 * read what we want. 486 * Return: 487 * Number of bytes in buffer. 0 for end of file, -1 for a read error. 488 */ 489 490 #if __STDC__ 491 int 492 ar_read(register char *buf, register int cnt) 493 #else 494 int 495 ar_read(buf, cnt) 496 register char *buf; 497 register int cnt; 498 #endif 499 { 500 register int res = 0; 501 502 /* 503 * if last i/o was in error, no more reads until reset or new volume 504 */ 505 if (lstrval <= 0) 506 return(lstrval); 507 508 /* 509 * how we read must be based on device type 510 */ 511 switch (artyp) { 512 case ISTAPE: 513 if ((res = read(arfd, buf, cnt)) > 0) { 514 /* 515 * CAUTION: tape systems may not always return the same 516 * sized records so we leave blksz == MAXBLK. The 517 * physical record size that a tape drive supports is 518 * very hard to determine in a uniform and portable 519 * manner. 520 */ 521 io_ok = 1; 522 if (res != rdblksz) { 523 /* 524 * Record size changed. If this is happens on 525 * any record after the first, we probably have 526 * a tape drive which has a fixed record size 527 * we are getting multiple records in a single 528 * read). Watch out for record blocking that 529 * violates pax spec (must be a multiple of 530 * BLKMULT). 531 */ 532 rdblksz = res; 533 if (rdblksz % BLKMULT) 534 invld_rec = 1; 535 } 536 return(res); 537 } 538 break; 539 case ISREG: 540 case ISBLK: 541 case ISCHR: 542 case ISPIPE: 543 default: 544 /* 545 * Files are so easy to deal with. These other things cannot 546 * be trusted at all. So when we are dealing with character 547 * devices and pipes we just take what they have ready for us 548 * and return. Trying to do anything else with them runs the 549 * risk of failure. 550 */ 551 if ((res = read(arfd, buf, cnt)) > 0) { 552 io_ok = 1; 553 return(res); 554 } 555 break; 556 } 557 558 /* 559 * We are in trouble at this point, something is broken... 560 */ 561 lstrval = res; 562 if (res < 0) 563 syswarn(1, errno, "Failed read on archive volume %d", arvol); 564 else 565 warn(0, "End of archive volume %d reached", arvol); 566 return(res); 567 } 568 569 /* 570 * ar_write() 571 * Write a specified number of bytes in supplied buffer to the archive 572 * device so it appears as a single "block". Deals with errors and tries 573 * to recover when faced with short writes. 574 * Return: 575 * Number of bytes written. 0 indicates end of volume reached and with no 576 * flaws (as best that can be detected). A -1 indicates an unrecoverable 577 * error in the archive occured. 578 */ 579 580 #if __STDC__ 581 int 582 ar_write(register char *buf, register int bsz) 583 #else 584 int 585 ar_write(buf, bsz) 586 register char *buf; 587 register int bsz; 588 #endif 589 { 590 register int res; 591 off_t cpos; 592 593 /* 594 * do not allow pax to create a "bad" archive. Once a write fails on 595 * an archive volume prevent further writes to it. 596 */ 597 if (lstrval <= 0) 598 return(lstrval); 599 600 if ((res = write(arfd, buf, bsz)) == bsz) { 601 wr_trail = 1; 602 io_ok = 1; 603 return(bsz); 604 } 605 /* 606 * write broke, see what we can do with it. We try to send any partial 607 * writes that may violate pax spec to the next archive volume. 608 */ 609 if (res < 0) 610 lstrval = res; 611 else 612 lstrval = 0; 613 614 switch (artyp) { 615 case ISREG: 616 if ((res > 0) && (res % BLKMULT)) { 617 /* 618 * try to fix up partial writes which are not BLKMULT 619 * in size by forcing the runt record to next archive 620 * volume 621 */ 622 if ((cpos = lseek(arfd, (off_t)0L, SEEK_CUR)) < 0) 623 break; 624 cpos -= (off_t)res; 625 if (ftruncate(arfd, cpos) < 0) 626 break; 627 res = lstrval = 0; 628 break; 629 } 630 if (res >= 0) 631 break; 632 /* 633 * if file is out of space, handle it like a return of 0 634 */ 635 if ((errno == ENOSPC) || (errno == EFBIG) || (errno == EDQUOT)) 636 res = lstrval = 0; 637 break; 638 case ISTAPE: 639 case ISCHR: 640 case ISBLK: 641 if (res >= 0) 642 break; 643 if (errno == EACCES) { 644 warn(0, "Write failed, archive is write protected."); 645 res = lstrval = 0; 646 return(0); 647 } 648 /* 649 * see if we reached the end of media, if so force a change to 650 * the next volume 651 */ 652 if ((errno == ENOSPC) || (errno == EIO) || (errno == ENXIO)) 653 res = lstrval = 0; 654 break; 655 case ISPIPE: 656 default: 657 /* 658 * we cannot fix errors to these devices 659 */ 660 break; 661 } 662 663 /* 664 * Better tell the user the bad news... 665 * if this is a block aligned archive format, we may have a bad archive 666 * if the format wants the header to start at a BLKMULT boundry. While 667 * we can deal with the mis-aligned data, it violates spec and other 668 * archive readers will likely fail. if the format is not block 669 * aligned, the user may be lucky (and the archive is ok). 670 */ 671 if (res >= 0) { 672 if (res > 0) 673 wr_trail = 1; 674 io_ok = 1; 675 } 676 677 /* 678 * If we were trying to rewrite the trailer and it didn't work, we 679 * must quit right away. 680 */ 681 if (!wr_trail && (res <= 0)) { 682 warn(1,"Unable to append, trailer re-write failed. Quitting."); 683 return(res); 684 } 685 686 if (res == 0) 687 warn(0, "End of archive volume %d reached", arvol); 688 else if (res < 0) 689 syswarn(1, errno, "Failed write to archive volume: %d", arvol); 690 else if (!frmt->blkalgn || ((res % frmt->blkalgn) == 0)) 691 warn(0,"WARNING: partial archive write. Archive MAY BE FLAWED"); 692 else 693 warn(1,"WARNING: partial archive write. Archive IS FLAWED"); 694 return(res); 695 } 696 697 /* 698 * ar_rdsync() 699 * Try to move past a bad spot on a flawed archive as needed to continue 700 * I/O. Clears error flags to allow I/O to continue. 701 * Return: 702 * 0 when ok to try i/o again, -1 otherwise. 703 */ 704 705 #if __STDC__ 706 int 707 ar_rdsync(void) 708 #else 709 int 710 ar_rdsync() 711 #endif 712 { 713 long fsbz; 714 off_t cpos; 715 off_t mpos; 716 struct mtop mb; 717 718 /* 719 * Fail resync attempts at user request (done) or this is going to be 720 * an update/append to a existing archive. if last i/o hit media end, 721 * we need to go to the next volume not try a resync 722 */ 723 if ((done > 0) || (lstrval == 0)) 724 return(-1); 725 726 if ((act == APPND) || (act == ARCHIVE)) { 727 warn(1, "Cannot allow updates to an archive with flaws."); 728 return(-1); 729 } 730 if (io_ok) 731 did_io = 1; 732 733 switch(artyp) { 734 case ISTAPE: 735 /* 736 * if the last i/o was a successful data transfer, we assume 737 * the fault is just a bad record on the tape that we are now 738 * past. If we did not get any data since the last resync try 739 * to move the tape foward one PHYSICAL record past any 740 * damaged tape section. Some tape drives are stubborn and need 741 * to be pushed. 742 */ 743 if (io_ok) { 744 io_ok = 0; 745 lstrval = 1; 746 break; 747 } 748 mb.mt_op = MTFSR; 749 mb.mt_count = 1; 750 if (ioctl(arfd, MTIOCTOP, &mb) < 0) 751 break; 752 lstrval = 1; 753 break; 754 case ISREG: 755 case ISCHR: 756 case ISBLK: 757 /* 758 * try to step over the bad part of the device. 759 */ 760 io_ok = 0; 761 if (((fsbz = arsb.st_blksize) <= 0) || (artyp != ISREG)) 762 fsbz = BLKMULT; 763 if ((cpos = lseek(arfd, (off_t)0L, SEEK_CUR)) < 0) 764 break; 765 mpos = fsbz - (cpos % (off_t)fsbz); 766 if (lseek(arfd, mpos, SEEK_CUR) < 0) 767 break; 768 lstrval = 1; 769 break; 770 case ISPIPE: 771 default: 772 /* 773 * cannot recover on these archive device types 774 */ 775 io_ok = 0; 776 break; 777 } 778 if (lstrval <= 0) { 779 warn(1, "Unable to recover from an archive read failure."); 780 return(-1); 781 } 782 warn(0, "Attempting to recover from an archive read failure."); 783 return(0); 784 } 785 786 /* 787 * ar_fow() 788 * Move the I/O position within the archive foward the specified number of 789 * bytes as supported by the device. If we cannot move the requested 790 * number of bytes, return the actual number of bytes moved in skipped. 791 * Return: 792 * 0 if moved the requested distance, -1 on complete failure, 1 on 793 * partial move (the amount moved is in skipped) 794 */ 795 796 #if __STDC__ 797 int 798 ar_fow(off_t sksz, off_t *skipped) 799 #else 800 int 801 ar_fow(sksz, skipped) 802 off_t sksz; 803 off_t *skipped; 804 #endif 805 { 806 off_t cpos; 807 off_t mpos; 808 809 *skipped = 0; 810 if (sksz <= 0) 811 return(0); 812 813 /* 814 * we cannot move foward at EOF or error 815 */ 816 if (lstrval <= 0) 817 return(lstrval); 818 819 /* 820 * Safer to read forward on devices where it is hard to find the end of 821 * the media without reading to it. With tapes we cannot be sure of the 822 * number of physical blocks to skip (we do not know physical block 823 * size at this point), so we must only read foward on tapes! 824 */ 825 if (artyp != ISREG) 826 return(0); 827 828 /* 829 * figure out where we are in the archive 830 */ 831 if ((cpos = lseek(arfd, (off_t)0L, SEEK_CUR)) >= 0) { 832 /* 833 * we can be asked to move farther than there are bytes in this 834 * volume, if so, just go to file end and let normal buf_fill() 835 * deal with the end of file (it will go to next volume by 836 * itself) 837 */ 838 if ((mpos = cpos + sksz) > arsb.st_size) { 839 *skipped = arsb.st_size - cpos; 840 mpos = arsb.st_size; 841 } else 842 *skipped = sksz; 843 if (lseek(arfd, mpos, SEEK_SET) >= 0) 844 return(0); 845 } 846 syswarn(1, errno, "Foward positioning operation on archive failed"); 847 lstrval = -1; 848 return(-1); 849 } 850 851 /* 852 * ar_rev() 853 * move the i/o position within the archive backwards the specified byte 854 * count as supported by the device. With tapes drives we RESET rdblksz to 855 * the PHYSICAL blocksize. 856 * NOTE: We should only be called to move backwards so we can rewrite the 857 * last records (the trailer) of an archive (APPEND). 858 * Return: 859 * 0 if moved the requested distance, -1 on complete failure 860 */ 861 862 #if __STDC__ 863 int 864 ar_rev(off_t sksz) 865 #else 866 int 867 ar_rev(sksz) 868 off_t sksz; 869 #endif 870 { 871 off_t cpos; 872 struct mtop mb; 873 register int phyblk; 874 875 /* 876 * make sure we do not have try to reverse on a flawed archive 877 */ 878 if (lstrval < 0) 879 return(lstrval); 880 881 switch(artyp) { 882 case ISPIPE: 883 if (sksz <= 0) 884 break; 885 /* 886 * cannot go backwards on these critters 887 */ 888 warn(1, "Reverse positioning on pipes is not supported."); 889 lstrval = -1; 890 return(-1); 891 case ISREG: 892 case ISBLK: 893 case ISCHR: 894 default: 895 if (sksz <= 0) 896 break; 897 898 /* 899 * For things other than files, backwards movement has a very 900 * high probability of failure as we really do not know the 901 * true attributes of the device we are talking to (the device 902 * may not even have the ability to lseek() in any direction). 903 * First we figure out where we are in the archive. 904 */ 905 if ((cpos = lseek(arfd, (off_t)0L, SEEK_CUR)) < 0) { 906 syswarn(1, errno, 907 "Unable to obtain current archive byte offset"); 908 lstrval = -1; 909 return(-1); 910 } 911 912 /* 913 * we may try to go backwards past the start when the archive 914 * is only a single record. If this hapens and we are on a 915 * multi volume archive, we need to go to the end of the 916 * previous volume and continue our movement backwards from 917 * there. 918 */ 919 if ((cpos -= sksz) < (off_t)0L) { 920 if (arvol > 1) { 921 /* 922 * this should never happen 923 */ 924 warn(1,"Reverse position on previous volume."); 925 lstrval = -1; 926 return(-1); 927 } 928 cpos = (off_t)0L; 929 } 930 if (lseek(arfd, cpos, SEEK_SET) < 0) { 931 syswarn(1, errno, "Unable to seek archive backwards"); 932 lstrval = -1; 933 return(-1); 934 } 935 break; 936 case ISTAPE: 937 /* 938 * Calculate and move the proper number of PHYSICAL tape 939 * blocks. If the sksz is not an even multiple of the physical 940 * tape size, we cannot do the move (this should never happen). 941 * (We also cannot handler trailers spread over two vols). 942 * get_phys() also makes sure we are in front of the filemark. 943 */ 944 if ((phyblk = get_phys()) <= 0) { 945 lstrval = -1; 946 return(-1); 947 } 948 949 /* 950 * make sure future tape reads only go by physical tape block 951 * size (set rdblksz to the real size). 952 */ 953 rdblksz = phyblk; 954 955 /* 956 * if no movement is required, just return (we must be after 957 * get_phys() so the physical blocksize is properly set) 958 */ 959 if (sksz <= 0) 960 break; 961 962 /* 963 * ok we have to move. Make sure the tape drive can do it. 964 */ 965 if (sksz % phyblk) { 966 warn(1, 967 "Tape drive unable to backspace requested amount"); 968 lstrval = -1; 969 return(-1); 970 } 971 972 /* 973 * move backwards the requested number of bytes 974 */ 975 mb.mt_op = MTBSR; 976 mb.mt_count = sksz/phyblk; 977 if (ioctl(arfd, MTIOCTOP, &mb) < 0) { 978 syswarn(1,errno, "Unable to backspace tape %d blocks.", 979 mb.mt_count); 980 lstrval = -1; 981 return(-1); 982 } 983 break; 984 } 985 lstrval = 1; 986 return(0); 987 } 988 989 /* 990 * get_phys() 991 * Determine the physical block size on a tape drive. We need the physical 992 * block size so we know how many bytes we skip over when we move with 993 * mtio commands. We also make sure we are BEFORE THE TAPE FILEMARK when 994 * return. 995 * This is one really SLOW routine... 996 * Return: 997 * physical block size if ok (ok > 0), -1 otherwise 998 */ 999 1000 #if __STDC__ 1001 static int 1002 get_phys(void) 1003 #else 1004 static int 1005 get_phys() 1006 #endif 1007 { 1008 register int padsz = 0; 1009 register int res; 1010 register int phyblk; 1011 struct mtop mb; 1012 char scbuf[MAXBLK]; 1013 1014 /* 1015 * move to the file mark, and then back up one record and read it. 1016 * this should tell us the physical record size the tape is using. 1017 */ 1018 if (lstrval == 1) { 1019 /* 1020 * we know we are at file mark when we get back a 0 from 1021 * read() 1022 */ 1023 while ((res = read(arfd, scbuf, sizeof(scbuf))) > 0) 1024 padsz += res; 1025 if (res < 0) { 1026 syswarn(1, errno, "Unable to locate tape filemark."); 1027 return(-1); 1028 } 1029 } 1030 1031 /* 1032 * move backwards over the file mark so we are at the end of the 1033 * last record. 1034 */ 1035 mb.mt_op = MTBSF; 1036 mb.mt_count = 1; 1037 if (ioctl(arfd, MTIOCTOP, &mb) < 0) { 1038 syswarn(1, errno, "Unable to backspace over tape filemark."); 1039 return(-1); 1040 } 1041 1042 /* 1043 * move backwards so we are in front of the last record and read it to 1044 * get physical tape blocksize. 1045 */ 1046 mb.mt_op = MTBSR; 1047 mb.mt_count = 1; 1048 if (ioctl(arfd, MTIOCTOP, &mb) < 0) { 1049 syswarn(1, errno, "Unable to backspace over last tape block."); 1050 return(-1); 1051 } 1052 if ((phyblk = read(arfd, scbuf, sizeof(scbuf))) <= 0) { 1053 syswarn(1, errno, "Cannot determine archive tape blocksize."); 1054 return(-1); 1055 } 1056 1057 /* 1058 * read foward to the file mark, then back up in front of the filemark 1059 * (this is a bit paranoid, but should be safe to do). 1060 */ 1061 while ((res = read(arfd, scbuf, sizeof(scbuf))) > 0) 1062 ; 1063 if (res < 0) { 1064 syswarn(1, errno, "Unable to locate tape filemark."); 1065 return(-1); 1066 } 1067 mb.mt_op = MTBSF; 1068 mb.mt_count = 1; 1069 if (ioctl(arfd, MTIOCTOP, &mb) < 0) { 1070 syswarn(1, errno, "Unable to backspace over tape filemark."); 1071 return(-1); 1072 } 1073 1074 /* 1075 * set lstrval so we know that the filemark has not been seen 1076 */ 1077 lstrval = 1; 1078 1079 /* 1080 * return if there was no padding 1081 */ 1082 if (padsz == 0) 1083 return(phyblk); 1084 1085 /* 1086 * make sure we can move backwards over the padding. (this should 1087 * never fail). 1088 */ 1089 if (padsz % phyblk) { 1090 warn(1, "Tape drive unable to backspace requested amount"); 1091 return(-1); 1092 } 1093 1094 /* 1095 * move backwards over the padding so the head is where it was when 1096 * we were first called (if required). 1097 */ 1098 mb.mt_op = MTBSR; 1099 mb.mt_count = padsz/phyblk; 1100 if (ioctl(arfd, MTIOCTOP, &mb) < 0) { 1101 syswarn(1,errno,"Unable to backspace tape over %d pad blocks", 1102 mb.mt_count); 1103 return(-1); 1104 } 1105 return(phyblk); 1106 } 1107 1108 /* 1109 * ar_next() 1110 * prompts the user for the next volume in this archive. For some devices 1111 * we may allow the media to be changed. Otherwise a new archive is 1112 * prompted for. By pax spec, if there is no controlling tty or an eof is 1113 * read on tty input, we must quit pax. 1114 * Return: 1115 * 0 when ready to continue, -1 when all done 1116 */ 1117 1118 #if __STDC__ 1119 int 1120 ar_next(void) 1121 #else 1122 int 1123 ar_next() 1124 #endif 1125 { 1126 char buf[PAXPATHLEN+2]; 1127 static int freeit = 0; 1128 sigset_t o_mask; 1129 1130 /* 1131 * WE MUST CLOSE THE DEVICE. A lot of devices must see last close, (so 1132 * things like writing EOF etc will be done) (Watch out ar_close() can 1133 * also be called via a signal handler, so we must prevent a race. 1134 */ 1135 if (sigprocmask(SIG_BLOCK, &s_mask, &o_mask) < 0) 1136 syswarn(0, errno, "Unable to set signal mask"); 1137 ar_close(); 1138 if (sigprocmask(SIG_SETMASK, &o_mask, (sigset_t *)NULL) < 0) 1139 syswarn(0, errno, "Unable to restore signal mask"); 1140 1141 if (done || !wr_trail) 1142 return(-1); 1143 1144 tty_prnt("\nATTENTION! %s archive volume change required.\n", argv0); 1145 1146 /* 1147 * if i/o is on stdin or stdout, we cannot reopen it (we do not know 1148 * the name), the user will be forced to type it in. 1149 */ 1150 if (strcmp(arcname, STDO) && strcmp(arcname, STDN) && (artyp != ISREG) 1151 && (artyp != ISPIPE)) { 1152 if (artyp == ISTAPE) { 1153 tty_prnt("%s ready for archive tape volume: %d\n", 1154 arcname, arvol); 1155 tty_prnt("Load the NEXT TAPE on the tape drive"); 1156 } else { 1157 tty_prnt("%s ready for archive volume: %d\n", 1158 arcname, arvol); 1159 tty_prnt("Load the NEXT STORAGE MEDIA (if required)"); 1160 } 1161 1162 if ((act == ARCHIVE) || (act == APPND)) 1163 tty_prnt(" and make sure it is WRITE ENABLED.\n"); 1164 else 1165 tty_prnt("\n"); 1166 1167 for(;;) { 1168 tty_prnt("Type \"y\" to continue, \".\" to quit %s,", 1169 argv0); 1170 tty_prnt(" or \"s\" to switch to new device.\nIf you"); 1171 tty_prnt(" cannot change storage media, type \"s\"\n"); 1172 tty_prnt("Is the device ready and online? > "); 1173 1174 if ((tty_read(buf,sizeof(buf))<0) || !strcmp(buf,".")){ 1175 done = 1; 1176 lstrval = -1; 1177 tty_prnt("Quitting %s!\n", argv0); 1178 vfpart = 0; 1179 return(-1); 1180 } 1181 1182 if ((buf[0] == '\0') || (buf[1] != '\0')) { 1183 tty_prnt("%s unknown command, try again\n",buf); 1184 continue; 1185 } 1186 1187 switch (buf[0]) { 1188 case 'y': 1189 case 'Y': 1190 /* 1191 * we are to continue with the same device 1192 */ 1193 if (ar_open(arcname) >= 0) 1194 return(0); 1195 tty_prnt("Cannot re-open %s, try again\n", 1196 arcname); 1197 continue; 1198 case 's': 1199 case 'S': 1200 /* 1201 * user wants to open a different device 1202 */ 1203 tty_prnt("Switching to a different archive\n"); 1204 break; 1205 default: 1206 tty_prnt("%s unknown command, try again\n",buf); 1207 continue; 1208 } 1209 break; 1210 } 1211 } else 1212 tty_prnt("Ready for archive volume: %d\n", arvol); 1213 1214 /* 1215 * have to go to a different archive 1216 */ 1217 for (;;) { 1218 tty_prnt("Input archive name or \".\" to quit %s.\n", argv0); 1219 tty_prnt("Archive name > "); 1220 1221 if ((tty_read(buf, sizeof(buf)) < 0) || !strcmp(buf, ".")) { 1222 done = 1; 1223 lstrval = -1; 1224 tty_prnt("Quitting %s!\n", argv0); 1225 vfpart = 0; 1226 return(-1); 1227 } 1228 if (buf[0] == '\0') { 1229 tty_prnt("Empty file name, try again\n"); 1230 continue; 1231 } 1232 if (!strcmp(buf, "..")) { 1233 tty_prnt("Illegal file name: .. try again\n"); 1234 continue; 1235 } 1236 if (strlen(buf) > PAXPATHLEN) { 1237 tty_prnt("File name too long, try again\n"); 1238 continue; 1239 } 1240 1241 /* 1242 * try to open new archive 1243 */ 1244 if (ar_open(buf) >= 0) { 1245 if (freeit) { 1246 (void)free(arcname); 1247 freeit = 0; 1248 } 1249 if ((arcname = strdup(buf)) == NULL) { 1250 done = 1; 1251 lstrval = -1; 1252 warn(0, "Cannot save archive name."); 1253 return(-1); 1254 } 1255 freeit = 1; 1256 break; 1257 } 1258 tty_prnt("Cannot open %s, try again\n", buf); 1259 continue; 1260 } 1261 return(0); 1262 } 1263