1/* $OpenBSD: buf_subs.c,v 1.21 2005/11/09 19:59:06 otto Exp $ */ 2/* $NetBSD: buf_subs.c,v 1.5 1995/03/21 09:07:08 cgd Exp $ */ 3 4/*- 5 * Copyright (c) 1992 Keith Muller. 6 * Copyright (c) 1992, 1993 7 * The Regents of the University of California. All rights reserved. 8 * 9 * This code is derived from software contributed to Berkeley by 10 * Keith Muller of the University of California, San Diego. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 */ 36 37#ifndef lint 38#if 0 39static const char sccsid[] = "@(#)buf_subs.c 8.2 (Berkeley) 4/18/94"; 40#else 41static const char rcsid[] = "$OpenBSD: buf_subs.c,v 1.21 2005/11/09 19:59:06 otto Exp $"; 42#endif 43#endif /* not lint */ 44 45#include <sys/types.h> 46#include <sys/time.h> 47#include <sys/stat.h> 48#include <sys/param.h> 49#include <stdio.h> 50#include <errno.h> 51#include <unistd.h> 52#include <stdlib.h> 53#include <string.h> 54#include "pax.h" 55#include "extern.h" 56 57/* 58 * routines which implement archive and file buffering 59 */ 60 61#define MINFBSZ 512 /* default block size for hole detect */ 62#define MAXFLT 10 /* default media read error limit */ 63 64/* 65 * Need to change bufmem to dynamic allocation when the upper 66 * limit on blocking size is removed (though that will violate pax spec) 67 * MAXBLK define and tests will also need to be updated. 68 */ 69static char bufmem[MAXBLK+BLKMULT]; /* i/o buffer + pushback id space */ 70static char *buf; /* normal start of i/o buffer */ 71static char *bufend; /* end or last char in i/o buffer */ 72static char *bufpt; /* read/write point in i/o buffer */ 73int blksz = MAXBLK; /* block input/output size in bytes */ 74int wrblksz; /* user spec output size in bytes */ 75int maxflt = MAXFLT; /* MAX consecutive media errors */ 76int rdblksz; /* first read blksize (tapes only) */ 77off_t wrlimit; /* # of bytes written per archive vol */ 78off_t wrcnt; /* # of bytes written on current vol */ 79off_t rdcnt; /* # of bytes read on current vol */ 80 81/* 82 * wr_start() 83 * set up the buffering system to operate in a write mode 84 * Return: 85 * 0 if ok, -1 if the user specified write block size violates pax spec 86 */ 87 88int 89wr_start(void) 90{ 91 buf = &(bufmem[BLKMULT]); 92 /* 93 * Check to make sure the write block size meets pax specs. If the user 94 * does not specify a blocksize, we use the format default blocksize. 95 * We must be picky on writes, so we do not allow the user to create an 96 * archive that might be hard to read elsewhere. If all ok, we then 97 * open the first archive volume 98 */ 99 if (!wrblksz) 100 wrblksz = frmt->bsz; 101 if (wrblksz > MAXBLK) { 102 paxwarn(1, "Write block size of %d too large, maximium is: %d", 103 wrblksz, MAXBLK); 104 return(-1); 105 } 106 if (wrblksz % BLKMULT) { 107 paxwarn(1, "Write block size of %d is not a %d byte multiple", 108 wrblksz, BLKMULT); 109 return(-1); 110 } 111 if (wrblksz > MAXBLK_POSIX) { 112 paxwarn(0, "Write block size of %d larger than POSIX max %d, archive may not be portable", 113 wrblksz, MAXBLK_POSIX); 114 return(-1); 115 } 116 117 /* 118 * we only allow wrblksz to be used with all archive operations 119 */ 120 blksz = rdblksz = wrblksz; 121 if ((ar_open(arcname) < 0) && (ar_next() < 0)) 122 return(-1); 123 wrcnt = 0; 124 bufend = buf + wrblksz; 125 bufpt = buf; 126 return(0); 127} 128 129/* 130 * rd_start() 131 * set up buffering system to read an archive 132 * Return: 133 * 0 if ok, -1 otherwise 134 */ 135 136int 137rd_start(void) 138{ 139 /* 140 * leave space for the header pushback (see get_arc()). If we are 141 * going to append and user specified a write block size, check it 142 * right away 143 */ 144 buf = &(bufmem[BLKMULT]); 145 if ((act == APPND) && wrblksz) { 146 if (wrblksz > MAXBLK) { 147 paxwarn(1,"Write block size %d too large, maximium is: %d", 148 wrblksz, MAXBLK); 149 return(-1); 150 } 151 if (wrblksz % BLKMULT) { 152 paxwarn(1, "Write block size %d is not a %d byte multiple", 153 wrblksz, BLKMULT); 154 return(-1); 155 } 156 } 157 158 /* 159 * open the archive 160 */ 161 if ((ar_open(arcname) < 0) && (ar_next() < 0)) 162 return(-1); 163 bufend = buf + rdblksz; 164 bufpt = bufend; 165 rdcnt = 0; 166 return(0); 167} 168 169/* 170 * cp_start() 171 * set up buffer system for copying within the file system 172 */ 173 174void 175cp_start(void) 176{ 177 buf = &(bufmem[BLKMULT]); 178 rdblksz = blksz = MAXBLK; 179} 180 181/* 182 * appnd_start() 183 * Set up the buffering system to append new members to an archive that 184 * was just read. The last block(s) of an archive may contain a format 185 * specific trailer. To append a new member, this trailer has to be 186 * removed from the archive. The first byte of the trailer is replaced by 187 * the start of the header of the first file added to the archive. The 188 * format specific end read function tells us how many bytes to move 189 * backwards in the archive to be positioned BEFORE the trailer. Two 190 * different position have to be adjusted, the O.S. file offset (e.g. the 191 * position of the tape head) and the write point within the data we have 192 * stored in the read (soon to become write) buffer. We may have to move 193 * back several records (the number depends on the size of the archive 194 * record and the size of the format trailer) to read up the record where 195 * the first byte of the trailer is recorded. Trailers may span (and 196 * overlap) record boundaries. 197 * We first calculate which record has the first byte of the trailer. We 198 * move the OS file offset back to the start of this record and read it 199 * up. We set the buffer write pointer to be at this byte (the byte where 200 * the trailer starts). We then move the OS file pointer back to the 201 * start of this record so a flush of this buffer will replace the record 202 * in the archive. 203 * A major problem is rewriting this last record. For archives stored 204 * on disk files, this is trivial. However, many devices are really picky 205 * about the conditions under which they will allow a write to occur. 206 * Often devices restrict the conditions where writes can be made, 207 * so it may not be feasible to append archives stored on all types of 208 * devices. 209 * Return: 210 * 0 for success, -1 for failure 211 */ 212 213int 214appnd_start(off_t skcnt) 215{ 216 int res; 217 off_t cnt; 218 219 if (exit_val != 0) { 220 paxwarn(0, "Cannot append to an archive that may have flaws."); 221 return(-1); 222 } 223 /* 224 * if the user did not specify a write blocksize, inherit the size used 225 * in the last archive volume read. (If a is set we still use rdblksz 226 * until next volume, cannot shift sizes within a single volume). 227 */ 228 if (!wrblksz) 229 wrblksz = blksz = rdblksz; 230 else 231 blksz = rdblksz; 232 233 /* 234 * make sure that this volume allows appends 235 */ 236 if (ar_app_ok() < 0) 237 return(-1); 238 239 /* 240 * Calculate bytes to move back and move in front of record where we 241 * need to start writing from. Remember we have to add in any padding 242 * that might be in the buffer after the trailer in the last block. We 243 * travel skcnt + padding ROUNDED UP to blksize. 244 */ 245 skcnt += bufend - bufpt; 246 if ((cnt = (skcnt/blksz) * blksz) < skcnt) 247 cnt += blksz; 248 if (ar_rev((off_t)cnt) < 0) 249 goto out; 250 251 /* 252 * We may have gone too far if there is valid data in the block we are 253 * now in front of, read up the block and position the pointer after 254 * the valid data. 255 */ 256 if ((cnt -= skcnt) > 0) { 257 /* 258 * watch out for stupid tape drives. ar_rev() will set rdblksz 259 * to be real physical blocksize so we must loop until we get 260 * the old rdblksz (now in blksz). If ar_rev() fouls up the 261 * determination of the physical block size, we will fail. 262 */ 263 bufpt = buf; 264 bufend = buf + blksz; 265 while (bufpt < bufend) { 266 if ((res = ar_read(bufpt, rdblksz)) <= 0) 267 goto out; 268 bufpt += res; 269 } 270 if (ar_rev((off_t)(bufpt - buf)) < 0) 271 goto out; 272 bufpt = buf + cnt; 273 bufend = buf + blksz; 274 } else { 275 /* 276 * buffer is empty 277 */ 278 bufend = buf + blksz; 279 bufpt = buf; 280 } 281 rdblksz = blksz; 282 rdcnt -= skcnt; 283 wrcnt = 0; 284 285 /* 286 * At this point we are ready to write. If the device requires special 287 * handling to write at a point were previously recorded data resides, 288 * that is handled in ar_set_wr(). From now on we operate under normal 289 * ARCHIVE mode (write) conditions 290 */ 291 if (ar_set_wr() < 0) 292 return(-1); 293 act = ARCHIVE; 294 return(0); 295 296 out: 297 paxwarn(1, "Unable to rewrite archive trailer, cannot append."); 298 return(-1); 299} 300 301/* 302 * rd_sync() 303 * A read error occurred on this archive volume. Resync the buffer and 304 * try to reset the device (if possible) so we can continue to read. Keep 305 * trying to do this until we get a valid read, or we reach the limit on 306 * consecutive read faults (at which point we give up). The user can 307 * adjust the read error limit through a command line option. 308 * Returns: 309 * 0 on success, and -1 on failure 310 */ 311 312int 313rd_sync(void) 314{ 315 int errcnt = 0; 316 int res; 317 318 /* 319 * if the user says bail out on first fault, we are out of here... 320 */ 321 if (maxflt == 0) 322 return(-1); 323 if (act == APPND) { 324 paxwarn(1, "Unable to append when there are archive read errors."); 325 return(-1); 326 } 327 328 /* 329 * poke at device and try to get past media error 330 */ 331 if (ar_rdsync() < 0) { 332 if (ar_next() < 0) 333 return(-1); 334 else 335 rdcnt = 0; 336 } 337 338 for (;;) { 339 if ((res = ar_read(buf, blksz)) > 0) { 340 /* 341 * All right! got some data, fill that buffer 342 */ 343 bufpt = buf; 344 bufend = buf + res; 345 rdcnt += res; 346 return(0); 347 } 348 349 /* 350 * Oh well, yet another failed read... 351 * if error limit reached, ditch. o.w. poke device to move past 352 * bad media and try again. if media is badly damaged, we ask 353 * the poor (and upset user at this point) for the next archive 354 * volume. remember the goal on reads is to get the most we 355 * can extract out of the archive. 356 */ 357 if ((maxflt > 0) && (++errcnt > maxflt)) 358 paxwarn(0,"Archive read error limit (%d) reached",maxflt); 359 else if (ar_rdsync() == 0) 360 continue; 361 if (ar_next() < 0) 362 break; 363 rdcnt = 0; 364 errcnt = 0; 365 } 366 return(-1); 367} 368 369/* 370 * pback() 371 * push the data used during the archive id phase back into the I/O 372 * buffer. This is required as we cannot be sure that the header does NOT 373 * overlap a block boundary (as in the case we are trying to recover a 374 * flawed archived). This was not designed to be used for any other 375 * purpose. (What software engineering, HA!) 376 * WARNING: do not even THINK of pback greater than BLKMULT, unless the 377 * pback space is increased. 378 */ 379 380void 381pback(char *pt, int cnt) 382{ 383 bufpt -= cnt; 384 memcpy(bufpt, pt, cnt); 385 return; 386} 387 388/* 389 * rd_skip() 390 * skip forward in the archive during a archive read. Used to get quickly 391 * past file data and padding for files the user did NOT select. 392 * Return: 393 * 0 if ok, -1 failure, and 1 when EOF on the archive volume was detected. 394 */ 395 396int 397rd_skip(off_t skcnt) 398{ 399 off_t res; 400 off_t cnt; 401 off_t skipped = 0; 402 403 /* 404 * consume what data we have in the buffer. If we have to move forward 405 * whole records, we call the low level skip function to see if we can 406 * move within the archive without doing the expensive reads on data we 407 * do not want. 408 */ 409 if (skcnt == 0) 410 return(0); 411 res = MIN((bufend - bufpt), skcnt); 412 bufpt += res; 413 skcnt -= res; 414 415 /* 416 * if skcnt is now 0, then no additional i/o is needed 417 */ 418 if (skcnt == 0) 419 return(0); 420 421 /* 422 * We have to read more, calculate complete and partial record reads 423 * based on rdblksz. we skip over "cnt" complete records 424 */ 425 res = skcnt%rdblksz; 426 cnt = (skcnt/rdblksz) * rdblksz; 427 428 /* 429 * if the skip fails, we will have to resync. ar_fow will tell us 430 * how much it can skip over. We will have to read the rest. 431 */ 432 if (ar_fow(cnt, &skipped) < 0) 433 return(-1); 434 res += cnt - skipped; 435 rdcnt += skipped; 436 437 /* 438 * what is left we have to read (which may be the whole thing if 439 * ar_fow() told us the device can only read to skip records); 440 */ 441 while (res > 0L) { 442 cnt = bufend - bufpt; 443 /* 444 * if the read fails, we will have to resync 445 */ 446 if ((cnt <= 0) && ((cnt = buf_fill()) < 0)) 447 return(-1); 448 if (cnt == 0) 449 return(1); 450 cnt = MIN(cnt, res); 451 bufpt += cnt; 452 res -= cnt; 453 } 454 return(0); 455} 456 457/* 458 * wr_fin() 459 * flush out any data (and pad if required) the last block. We always pad 460 * with zero (even though we do not have to). Padding with 0 makes it a 461 * lot easier to recover if the archive is damaged. zero padding SHOULD 462 * BE a requirement.... 463 */ 464 465void 466wr_fin(void) 467{ 468 if (bufpt > buf) { 469 memset(bufpt, 0, bufend - bufpt); 470 bufpt = bufend; 471 (void)buf_flush(blksz); 472 } 473} 474 475/* 476 * wr_rdbuf() 477 * fill the write buffer from data passed to it in a buffer (usually used 478 * by format specific write routines to pass a file header). On failure we 479 * punt. We do not allow the user to continue to write flawed archives. 480 * We assume these headers are not very large (the memory copy we use is 481 * a bit expensive). 482 * Return: 483 * 0 if buffer was filled ok, -1 o.w. (buffer flush failure) 484 */ 485 486int 487wr_rdbuf(char *out, int outcnt) 488{ 489 int cnt; 490 491 /* 492 * while there is data to copy copy into the write buffer. when the 493 * write buffer fills, flush it to the archive and continue 494 */ 495 while (outcnt > 0) { 496 cnt = bufend - bufpt; 497 if ((cnt <= 0) && ((cnt = buf_flush(blksz)) < 0)) 498 return(-1); 499 /* 500 * only move what we have space for 501 */ 502 cnt = MIN(cnt, outcnt); 503 memcpy(bufpt, out, cnt); 504 bufpt += cnt; 505 out += cnt; 506 outcnt -= cnt; 507 } 508 return(0); 509} 510 511/* 512 * rd_wrbuf() 513 * copy from the read buffer into a supplied buffer a specified number of 514 * bytes. If the read buffer is empty fill it and continue to copy. 515 * usually used to obtain a file header for processing by a format 516 * specific read routine. 517 * Return 518 * number of bytes copied to the buffer, 0 indicates EOF on archive volume, 519 * -1 is a read error 520 */ 521 522int 523rd_wrbuf(char *in, int cpcnt) 524{ 525 int res; 526 int cnt; 527 int incnt = cpcnt; 528 529 /* 530 * loop until we fill the buffer with the requested number of bytes 531 */ 532 while (incnt > 0) { 533 cnt = bufend - bufpt; 534 if ((cnt <= 0) && ((cnt = buf_fill()) <= 0)) { 535 /* 536 * read error, return what we got (or the error if 537 * no data was copied). The caller must know that an 538 * error occurred and has the best knowledge what to 539 * do with it 540 */ 541 if ((res = cpcnt - incnt) > 0) 542 return(res); 543 return(cnt); 544 } 545 546 /* 547 * calculate how much data to copy based on whats left and 548 * state of buffer 549 */ 550 cnt = MIN(cnt, incnt); 551 memcpy(in, bufpt, cnt); 552 bufpt += cnt; 553 incnt -= cnt; 554 in += cnt; 555 } 556 return(cpcnt); 557} 558 559/* 560 * wr_skip() 561 * skip forward during a write. In other words add padding to the file. 562 * we add zero filled padding as it makes flawed archives much easier to 563 * recover from. the caller tells us how many bytes of padding to add 564 * This routine was not designed to add HUGE amount of padding, just small 565 * amounts (a few 512 byte blocks at most) 566 * Return: 567 * 0 if ok, -1 if there was a buf_flush failure 568 */ 569 570int 571wr_skip(off_t skcnt) 572{ 573 int cnt; 574 575 /* 576 * loop while there is more padding to add 577 */ 578 while (skcnt > 0L) { 579 cnt = bufend - bufpt; 580 if ((cnt <= 0) && ((cnt = buf_flush(blksz)) < 0)) 581 return(-1); 582 cnt = MIN(cnt, skcnt); 583 memset(bufpt, 0, cnt); 584 bufpt += cnt; 585 skcnt -= cnt; 586 } 587 return(0); 588} 589 590/* 591 * wr_rdfile() 592 * fill write buffer with the contents of a file. We are passed an open 593 * file descriptor to the file an the archive structure that describes the 594 * file we are storing. The variable "left" is modified to contain the 595 * number of bytes of the file we were NOT able to write to the archive. 596 * it is important that we always write EXACTLY the number of bytes that 597 * the format specific write routine told us to. The file can also get 598 * bigger, so reading to the end of file would create an improper archive, 599 * we just detect this case and warn the user. We never create a bad 600 * archive if we can avoid it. Of course trying to archive files that are 601 * active is asking for trouble. It we fail, we pass back how much we 602 * could NOT copy and let the caller deal with it. 603 * Return: 604 * 0 ok, -1 if archive write failure. a short read of the file returns a 605 * 0, but "left" is set to be greater than zero. 606 */ 607 608int 609wr_rdfile(ARCHD *arcn, int ifd, off_t *left) 610{ 611 int cnt; 612 int res = 0; 613 off_t size = arcn->sb.st_size; 614 struct stat sb; 615 616 /* 617 * while there are more bytes to write 618 */ 619 while (size > 0L) { 620 cnt = bufend - bufpt; 621 if ((cnt <= 0) && ((cnt = buf_flush(blksz)) < 0)) { 622 *left = size; 623 return(-1); 624 } 625 cnt = MIN(cnt, size); 626 if ((res = read(ifd, bufpt, cnt)) <= 0) 627 break; 628 size -= res; 629 bufpt += res; 630 } 631 632 /* 633 * better check the file did not change during this operation 634 * or the file read failed. 635 */ 636 if (res < 0) 637 syswarn(1, errno, "Read fault on %s", arcn->org_name); 638 else if (size != 0L) 639 paxwarn(1, "File changed size during read %s", arcn->org_name); 640 else if (fstat(ifd, &sb) < 0) 641 syswarn(1, errno, "Failed stat on %s", arcn->org_name); 642 else if (arcn->sb.st_mtime != sb.st_mtime) 643 paxwarn(1, "File %s was modified during copy to archive", 644 arcn->org_name); 645 *left = size; 646 return(0); 647} 648 649/* 650 * rd_wrfile() 651 * extract the contents of a file from the archive. If we are unable to 652 * extract the entire file (due to failure to write the file) we return 653 * the numbers of bytes we did NOT process. This way the caller knows how 654 * many bytes to skip past to find the next archive header. If the failure 655 * was due to an archive read, we will catch that when we try to skip. If 656 * the format supplies a file data crc value, we calculate the actual crc 657 * so that it can be compared to the value stored in the header 658 * NOTE: 659 * We call a special function to write the file. This function attempts to 660 * restore file holes (blocks of zeros) into the file. When files are 661 * sparse this saves space, and is a LOT faster. For non sparse files 662 * the performance hit is small. As of this writing, no archive supports 663 * information on where the file holes are. 664 * Return: 665 * 0 ok, -1 if archive read failure. if we cannot write the entire file, 666 * we return a 0 but "left" is set to be the amount unwritten 667 */ 668 669int 670rd_wrfile(ARCHD *arcn, int ofd, off_t *left) 671{ 672 int cnt = 0; 673 off_t size = arcn->sb.st_size; 674 int res = 0; 675 char *fnm = arcn->name; 676 int isem = 1; 677 int rem; 678 int sz = MINFBSZ; 679 struct stat sb; 680 u_int32_t crc = 0; 681 682 /* 683 * pass the blocksize of the file being written to the write routine, 684 * if the size is zero, use the default MINFBSZ 685 */ 686 if (ofd < 0) 687 sz = PAXPATHLEN + 1; /* GNU tar long link/file */ 688 else if (fstat(ofd, &sb) == 0) { 689 if (sb.st_blksize > 0) 690 sz = (int)sb.st_blksize; 691 } else 692 syswarn(0,errno,"Unable to obtain block size for file %s",fnm); 693 rem = sz; 694 *left = 0L; 695 696 /* 697 * Copy the archive to the file the number of bytes specified. We have 698 * to assume that we want to recover file holes as none of the archive 699 * formats can record the location of file holes. 700 */ 701 while (size > 0L) { 702 cnt = bufend - bufpt; 703 /* 704 * if we get a read error, we do not want to skip, as we may 705 * miss a header, so we do not set left, but if we get a write 706 * error, we do want to skip over the unprocessed data. 707 */ 708 if ((cnt <= 0) && ((cnt = buf_fill()) <= 0)) 709 break; 710 cnt = MIN(cnt, size); 711 if ((res = file_write(ofd,bufpt,cnt,&rem,&isem,sz,fnm)) <= 0) { 712 *left = size; 713 break; 714 } 715 716 if (docrc) { 717 /* 718 * update the actual crc value 719 */ 720 cnt = res; 721 while (--cnt >= 0) 722 crc += *bufpt++ & 0xff; 723 } else 724 bufpt += res; 725 size -= res; 726 } 727 728 /* 729 * if the last block has a file hole (all zero), we must make sure this 730 * gets updated in the file. We force the last block of zeros to be 731 * written. just closing with the file offset moved forward may not put 732 * a hole at the end of the file. 733 */ 734 if (isem && (arcn->sb.st_size > 0L)) 735 file_flush(ofd, fnm, isem); 736 737 /* 738 * if we failed from archive read, we do not want to skip 739 */ 740 if ((size > 0L) && (*left == 0L)) 741 return(-1); 742 743 /* 744 * some formats record a crc on file data. If so, then we compare the 745 * calculated crc to the crc stored in the archive 746 */ 747 if (docrc && (size == 0L) && (arcn->crc != crc)) 748 paxwarn(1,"Actual crc does not match expected crc %s",arcn->name); 749 return(0); 750} 751 752/* 753 * cp_file() 754 * copy the contents of one file to another. used during -rw phase of pax 755 * just as in rd_wrfile() we use a special write function to write the 756 * destination file so we can properly copy files with holes. 757 */ 758 759void 760cp_file(ARCHD *arcn, int fd1, int fd2) 761{ 762 int cnt; 763 off_t cpcnt = 0L; 764 int res = 0; 765 char *fnm = arcn->name; 766 int no_hole = 0; 767 int isem = 1; 768 int rem; 769 int sz = MINFBSZ; 770 struct stat sb; 771 772 /* 773 * check for holes in the source file. If none, we will use regular 774 * write instead of file write. 775 */ 776 if (((off_t)(arcn->sb.st_blocks * BLKMULT)) >= arcn->sb.st_size) 777 ++no_hole; 778 779 /* 780 * pass the blocksize of the file being written to the write routine, 781 * if the size is zero, use the default MINFBSZ 782 */ 783 if (fstat(fd2, &sb) == 0) { 784 if (sb.st_blksize > 0) 785 sz = sb.st_blksize; 786 } else 787 syswarn(0,errno,"Unable to obtain block size for file %s",fnm); 788 rem = sz; 789 790 /* 791 * read the source file and copy to destination file until EOF 792 */ 793 for (;;) { 794 if ((cnt = read(fd1, buf, blksz)) <= 0) 795 break; 796 if (no_hole) 797 res = write(fd2, buf, cnt); 798 else 799 res = file_write(fd2, buf, cnt, &rem, &isem, sz, fnm); 800 if (res != cnt) 801 break; 802 cpcnt += cnt; 803 } 804 805 /* 806 * check to make sure the copy is valid. 807 */ 808 if (res < 0) 809 syswarn(1, errno, "Failed write during copy of %s to %s", 810 arcn->org_name, arcn->name); 811 else if (cpcnt != arcn->sb.st_size) 812 paxwarn(1, "File %s changed size during copy to %s", 813 arcn->org_name, arcn->name); 814 else if (fstat(fd1, &sb) < 0) 815 syswarn(1, errno, "Failed stat of %s", arcn->org_name); 816 else if (arcn->sb.st_mtime != sb.st_mtime) 817 paxwarn(1, "File %s was modified during copy to %s", 818 arcn->org_name, arcn->name); 819 820 /* 821 * if the last block has a file hole (all zero), we must make sure this 822 * gets updated in the file. We force the last block of zeros to be 823 * written. just closing with the file offset moved forward may not put 824 * a hole at the end of the file. 825 */ 826 if (!no_hole && isem && (arcn->sb.st_size > 0L)) 827 file_flush(fd2, fnm, isem); 828 return; 829} 830 831/* 832 * buf_fill() 833 * fill the read buffer with the next record (or what we can get) from 834 * the archive volume. 835 * Return: 836 * Number of bytes of data in the read buffer, -1 for read error, and 837 * 0 when finished (user specified termination in ar_next()). 838 */ 839 840int 841buf_fill(void) 842{ 843 int cnt; 844 static int fini = 0; 845 846 if (fini) 847 return(0); 848 849 for (;;) { 850 /* 851 * try to fill the buffer. on error the next archive volume is 852 * opened and we try again. 853 */ 854 if ((cnt = ar_read(buf, blksz)) > 0) { 855 bufpt = buf; 856 bufend = buf + cnt; 857 rdcnt += cnt; 858 return(cnt); 859 } 860 861 /* 862 * errors require resync, EOF goes to next archive 863 */ 864 if (cnt < 0) 865 break; 866 if (ar_next() < 0) { 867 fini = 1; 868 return(0); 869 } 870 rdcnt = 0; 871 } 872 exit_val = 1; 873 return(-1); 874} 875 876/* 877 * buf_flush() 878 * force the write buffer to the archive. We are passed the number of 879 * bytes in the buffer at the point of the flush. When we change archives 880 * the record size might change. (either larger or smaller). 881 * Return: 882 * 0 if all is ok, -1 when a write error occurs. 883 */ 884 885int 886buf_flush(int bufcnt) 887{ 888 int cnt; 889 int push = 0; 890 int totcnt = 0; 891 892 /* 893 * if we have reached the user specified byte count for each archive 894 * volume, prompt for the next volume. (The non-standard -R flag). 895 * NOTE: If the wrlimit is smaller than wrcnt, we will always write 896 * at least one record. We always round limit UP to next blocksize. 897 */ 898 if ((wrlimit > 0) && (wrcnt > wrlimit)) { 899 paxwarn(0, "User specified archive volume byte limit reached."); 900 if (ar_next() < 0) { 901 wrcnt = 0; 902 exit_val = 1; 903 return(-1); 904 } 905 wrcnt = 0; 906 907 /* 908 * The new archive volume might have changed the size of the 909 * write blocksize. if so we figure out if we need to write 910 * (one or more times), or if there is now free space left in 911 * the buffer (it is no longer full). bufcnt has the number of 912 * bytes in the buffer, (the blocksize, at the point we were 913 * CALLED). Push has the amount of "extra" data in the buffer 914 * if the block size has shrunk from a volume change. 915 */ 916 bufend = buf + blksz; 917 if (blksz > bufcnt) 918 return(0); 919 if (blksz < bufcnt) 920 push = bufcnt - blksz; 921 } 922 923 /* 924 * We have enough data to write at least one archive block 925 */ 926 for (;;) { 927 /* 928 * write a block and check if it all went out ok 929 */ 930 cnt = ar_write(buf, blksz); 931 if (cnt == blksz) { 932 /* 933 * the write went ok 934 */ 935 wrcnt += cnt; 936 totcnt += cnt; 937 if (push > 0) { 938 /* we have extra data to push to the front. 939 * check for more than 1 block of push, and if 940 * so we loop back to write again 941 */ 942 memcpy(buf, bufend, push); 943 bufpt = buf + push; 944 if (push >= blksz) { 945 push -= blksz; 946 continue; 947 } 948 } else 949 bufpt = buf; 950 return(totcnt); 951 } else if (cnt > 0) { 952 /* 953 * Oh drat we got a partial write! 954 * if format doesnt care about alignment let it go, 955 * we warned the user in ar_write().... but this means 956 * the last record on this volume violates pax spec.... 957 */ 958 totcnt += cnt; 959 wrcnt += cnt; 960 bufpt = buf + cnt; 961 cnt = bufcnt - cnt; 962 memcpy(buf, bufpt, cnt); 963 bufpt = buf + cnt; 964 if (!frmt->blkalgn || ((cnt % frmt->blkalgn) == 0)) 965 return(totcnt); 966 break; 967 } 968 969 /* 970 * All done, go to next archive 971 */ 972 wrcnt = 0; 973 if (ar_next() < 0) 974 break; 975 976 /* 977 * The new archive volume might also have changed the block 978 * size. if so, figure out if we have too much or too little 979 * data for using the new block size 980 */ 981 bufend = buf + blksz; 982 if (blksz > bufcnt) 983 return(0); 984 if (blksz < bufcnt) 985 push = bufcnt - blksz; 986 } 987 988 /* 989 * write failed, stop pax. we must not create a bad archive! 990 */ 991 exit_val = 1; 992 return(-1); 993} 994