file_subs.c revision 1.16
1/* $NetBSD: file_subs.c,v 1.16 2000/02/17 03:06:13 itohy Exp $ */ 2 3/*- 4 * Copyright (c) 1992 Keith Muller. 5 * Copyright (c) 1992, 1993 6 * The Regents of the University of California. All rights reserved. 7 * 8 * This code is derived from software contributed to Berkeley by 9 * Keith Muller of the University of California, San Diego. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. All advertising materials mentioning features or use of this software 20 * must display the following acknowledgement: 21 * This product includes software developed by the University of 22 * California, Berkeley and its contributors. 23 * 4. Neither the name of the University nor the names of its contributors 24 * may be used to endorse or promote products derived from this software 25 * without specific prior written permission. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 30 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 37 * SUCH DAMAGE. 38 */ 39 40#include <sys/cdefs.h> 41#ifndef lint 42#if 0 43static char sccsid[] = "@(#)file_subs.c 8.1 (Berkeley) 5/31/93"; 44#else 45__RCSID("$NetBSD: file_subs.c,v 1.16 2000/02/17 03:06:13 itohy Exp $"); 46#endif 47#endif /* not lint */ 48 49#include <sys/types.h> 50#include <sys/time.h> 51#include <sys/stat.h> 52#include <unistd.h> 53#include <sys/param.h> 54#include <err.h> 55#include <fcntl.h> 56#include <string.h> 57#include <stdio.h> 58#include <ctype.h> 59#include <errno.h> 60#include <sys/uio.h> 61#include <stdlib.h> 62#include "pax.h" 63#include "extern.h" 64 65static int 66mk_link __P((char *,struct stat *,char *, int)); 67 68/* 69 * routines that deal with file operations such as: creating, removing; 70 * and setting access modes, uid/gid and times of files 71 */ 72 73#define FILEBITS (S_ISVTX | S_IRWXU | S_IRWXG | S_IRWXO) 74#define SETBITS (S_ISUID | S_ISGID) 75#define ABITS (FILEBITS | SETBITS) 76 77/* 78 * file_creat() 79 * Create and open a file. 80 * Return: 81 * file descriptor or -1 for failure 82 */ 83 84#if __STDC__ 85int 86file_creat(ARCHD *arcn) 87#else 88int 89file_creat(arcn) 90 ARCHD *arcn; 91#endif 92{ 93 int fd = -1; 94 mode_t file_mode; 95 int oerrno; 96 97 /* 98 * assume file doesn't exist, so just try to create it, most times this 99 * works. We have to take special handling when the file does exist. To 100 * detect this, we use O_EXCL. For example when trying to create a 101 * file and a character device or fifo exists with the same name, we 102 * can accidently open the device by mistake (or block waiting to open) 103 * If we find that the open has failed, then figure spend the effore to 104 * figure out why. This strategy was found to have better average 105 * performance in common use than checking the file (and the path) 106 * first with lstat. 107 */ 108 file_mode = arcn->sb.st_mode & FILEBITS; 109 if ((fd = open(arcn->name, O_WRONLY | O_CREAT | O_TRUNC | O_EXCL, 110 file_mode)) >= 0) 111 return(fd); 112 113 /* 114 * the file seems to exist. First we try to get rid of it (found to be 115 * the second most common failure when traced). If this fails, only 116 * then we go to the expense to check and create the path to the file 117 */ 118 if (unlnk_exist(arcn->name, arcn->type) != 0) 119 return(-1); 120 121 for (;;) { 122 /* 123 * try to open it again, if this fails, check all the nodes in 124 * the path and give it a final try. if chk_path() finds that 125 * it cannot fix anything, we will skip the last attempt 126 */ 127 if ((fd = open(arcn->name, O_WRONLY | O_CREAT | O_TRUNC, 128 file_mode)) >= 0) 129 break; 130 oerrno = errno; 131 if (chk_path(arcn->name,arcn->sb.st_uid,arcn->sb.st_gid) < 0) { 132 syswarn(1, oerrno, "Unable to create %s", arcn->name); 133 return(-1); 134 } 135 } 136 return(fd); 137} 138 139/* 140 * file_close() 141 * Close file descriptor to a file just created by pax. Sets modes, 142 * ownership and times as required. 143 * Return: 144 * 0 for success, -1 for failure 145 */ 146 147#if __STDC__ 148void 149file_close(ARCHD *arcn, int fd) 150#else 151void 152file_close(arcn, fd) 153 ARCHD *arcn; 154 int fd; 155#endif 156{ 157 int res = 0; 158 159 if (fd < 0) 160 return; 161 if (close(fd) < 0) 162 syswarn(0, errno, "Unable to close file descriptor on %s", 163 arcn->name); 164 165 /* 166 * set owner/groups first as this may strip off mode bits we want 167 * then set file permission modes. Then set file access and 168 * modification times. 169 */ 170 if (pids) 171 res = set_ids(arcn->name, arcn->sb.st_uid, arcn->sb.st_gid); 172 173 /* 174 * IMPORTANT SECURITY NOTE: 175 * if not preserving mode or we cannot set uid/gid, then PROHIBIT 176 * set uid/gid bits 177 */ 178 if (!pmode || res) 179 arcn->sb.st_mode &= ~(SETBITS); 180 if (pmode) 181 set_pmode(arcn->name, arcn->sb.st_mode); 182 if (patime || pmtime) 183 set_ftime(arcn->name, arcn->sb.st_mtime, arcn->sb.st_atime, 0); 184 if (pfflags && arcn->type != PAX_SLK) 185 set_chflags(arcn->name, arcn->sb.st_flags); 186} 187 188/* 189 * lnk_creat() 190 * Create a hard link to arcn->ln_name from arcn->name. arcn->ln_name 191 * must exist; 192 * Return: 193 * 0 if ok, -1 otherwise 194 */ 195 196#if __STDC__ 197int 198lnk_creat(ARCHD *arcn) 199#else 200int 201lnk_creat(arcn) 202 ARCHD *arcn; 203#endif 204{ 205 struct stat sb; 206 207 /* 208 * we may be running as root, so we have to be sure that link target 209 * is not a directory, so we lstat and check 210 */ 211 if (lstat(arcn->ln_name, &sb) < 0) { 212 syswarn(1,errno,"Unable to link to %s from %s", arcn->ln_name, 213 arcn->name); 214 return(-1); 215 } 216 217 if (S_ISDIR(sb.st_mode)) { 218 tty_warn(1, "A hard link to the directory %s is not allowed", 219 arcn->ln_name); 220 return(-1); 221 } 222 223 return(mk_link(arcn->ln_name, &sb, arcn->name, 0)); 224} 225 226/* 227 * cross_lnk() 228 * Create a hard link to arcn->org_name from arcn->name. Only used in copy 229 * with the -l flag. No warning or error if this does not succeed (we will 230 * then just create the file) 231 * Return: 232 * 1 if copy() should try to create this file node 233 * 0 if cross_lnk() ok, -1 for fatal flaw (like linking to self). 234 */ 235 236#if __STDC__ 237int 238cross_lnk(ARCHD *arcn) 239#else 240int 241cross_lnk(arcn) 242 ARCHD *arcn; 243#endif 244{ 245 /* 246 * try to make a link to orginal file (-l flag in copy mode). make sure 247 * we do not try to link to directories in case we are running as root 248 * (and it might succeed). 249 */ 250 if (arcn->type == PAX_DIR) 251 return(1); 252 return(mk_link(arcn->org_name, &(arcn->sb), arcn->name, 1)); 253} 254 255/* 256 * chk_same() 257 * In copy mode if we are not trying to make hard links between the src 258 * and destinations, make sure we are not going to overwrite ourselves by 259 * accident. This slows things down a little, but we have to protect all 260 * those people who make typing errors. 261 * Return: 262 * 1 the target does not exist, go ahead and copy 263 * 0 skip it file exists (-k) or may be the same as source file 264 */ 265 266#if __STDC__ 267int 268chk_same(ARCHD *arcn) 269#else 270int 271chk_same(arcn) 272 ARCHD *arcn; 273#endif 274{ 275 struct stat sb; 276 277 /* 278 * if file does not exist, return. if file exists and -k, skip it 279 * quietly 280 */ 281 if (lstat(arcn->name, &sb) < 0) 282 return(1); 283 if (kflag) 284 return(0); 285 286 /* 287 * better make sure the user does not have src == dest by mistake 288 */ 289 if ((arcn->sb.st_dev == sb.st_dev) && (arcn->sb.st_ino == sb.st_ino)) { 290 tty_warn(1, "Unable to copy %s, file would overwrite itself", 291 arcn->name); 292 return(0); 293 } 294 return(1); 295} 296 297/* 298 * mk_link() 299 * try to make a hard link between two files. if ign set, we do not 300 * complain. 301 * Return: 302 * 0 if successful (or we are done with this file but no error, such as 303 * finding the from file exists and the user has set -k). 304 * 1 when ign was set to indicates we could not make the link but we 305 * should try to copy/extract the file as that might work (and is an 306 * allowed option). -1 an error occurred. 307 */ 308 309#if __STDC__ 310static int 311mk_link(char *to, struct stat *to_sb, char *from, 312 int ign) 313#else 314static int 315mk_link(to, to_sb, from, ign) 316 char *to; 317 struct stat *to_sb; 318 char *from; 319 int ign; 320#endif 321{ 322 struct stat sb; 323 int oerrno; 324 325 /* 326 * if from file exists, it has to be unlinked to make the link. If the 327 * file exists and -k is set, skip it quietly 328 */ 329 if (lstat(from, &sb) == 0) { 330 if (kflag) 331 return(0); 332 333 /* 334 * make sure it is not the same file, protect the user 335 */ 336 if ((to_sb->st_dev==sb.st_dev)&&(to_sb->st_ino == sb.st_ino)) { 337 tty_warn(1, "Unable to link file %s to itself", to); 338 return(-1);; 339 } 340 341 /* 342 * try to get rid of the file, based on the type 343 */ 344 if (S_ISDIR(sb.st_mode)) { 345 if (rmdir(from) < 0) { 346 syswarn(1, errno, "Unable to remove %s", from); 347 return(-1); 348 } 349 } else if (unlink(from) < 0) { 350 if (!ign) { 351 syswarn(1, errno, "Unable to remove %s", from); 352 return(-1); 353 } 354 return(1); 355 } 356 } 357 358 /* 359 * from file is gone (or did not exist), try to make the hard link. 360 * if it fails, check the path and try it again (if chk_path() says to 361 * try again) 362 */ 363 for (;;) { 364 if (link(to, from) == 0) 365 break; 366 oerrno = errno; 367 if (chk_path(from, to_sb->st_uid, to_sb->st_gid) == 0) 368 continue; 369 if (!ign) { 370 syswarn(1, oerrno, "Could not link to %s from %s", to, 371 from); 372 return(-1); 373 } 374 return(1); 375 } 376 377 /* 378 * all right the link was made 379 */ 380 return(0); 381} 382 383/* 384 * node_creat() 385 * create an entry in the file system (other than a file or hard link). 386 * If successful, sets uid/gid modes and times as required. 387 * Return: 388 * 0 if ok, -1 otherwise 389 */ 390 391#if __STDC__ 392int 393node_creat(ARCHD *arcn) 394#else 395int 396node_creat(arcn) 397 ARCHD *arcn; 398#endif 399{ 400 int res; 401 int ign = 0; 402 int oerrno; 403 int pass = 0; 404 mode_t file_mode; 405 struct stat sb; 406 407 /* 408 * create node based on type, if that fails try to unlink the node and 409 * try again. finally check the path and try again. As noted in the 410 * file and link creation routines, this method seems to exhibit the 411 * best performance in general use workloads. 412 */ 413 file_mode = arcn->sb.st_mode & FILEBITS; 414 415 for (;;) { 416 switch(arcn->type) { 417 case PAX_DIR: 418 res = mkdir(arcn->name, file_mode); 419 if (ign) 420 res = 0; 421 break; 422 case PAX_CHR: 423 file_mode |= S_IFCHR; 424 res = mknod(arcn->name, file_mode, arcn->sb.st_rdev); 425 break; 426 case PAX_BLK: 427 file_mode |= S_IFBLK; 428 res = mknod(arcn->name, file_mode, arcn->sb.st_rdev); 429 break; 430 case PAX_FIF: 431 res = mkfifo(arcn->name, file_mode); 432 break; 433 case PAX_SCK: 434 /* 435 * Skip sockets, operation has no meaning under BSD 436 */ 437 tty_warn(0, 438 "%s skipped. Sockets cannot be copied or extracted", 439 arcn->name); 440 return(-1); 441 case PAX_SLK: 442 res = symlink(arcn->ln_name, arcn->name); 443 break; 444 case PAX_CTG: 445 case PAX_HLK: 446 case PAX_HRG: 447 case PAX_REG: 448 default: 449 /* 450 * we should never get here 451 */ 452 tty_warn(0, "%s has an unknown file type, skipping", 453 arcn->name); 454 return(-1); 455 } 456 457 /* 458 * if we were able to create the node break out of the loop, 459 * otherwise try to unlink the node and try again. if that 460 * fails check the full path and try a final time. 461 */ 462 if (res == 0) 463 break; 464 465 /* 466 * we failed to make the node 467 */ 468 oerrno = errno; 469 if ((ign = unlnk_exist(arcn->name, arcn->type)) < 0) 470 return(-1); 471 472 if (++pass <= 1) 473 continue; 474 475 if (chk_path(arcn->name,arcn->sb.st_uid,arcn->sb.st_gid) < 0) { 476 syswarn(1, oerrno, "Could not create: %s", arcn->name); 477 return(-1); 478 } 479 } 480 481 /* 482 * we were able to create the node. set uid/gid, modes and times 483 */ 484 if (pids) 485 res = set_ids(arcn->name, arcn->sb.st_uid, arcn->sb.st_gid); 486 else 487 res = 0; 488 489 /* 490 * IMPORTANT SECURITY NOTE: 491 * if not preserving mode or we cannot set uid/gid, then PROHIBIT any 492 * set uid/gid bits 493 */ 494 if (!pmode || res) 495 arcn->sb.st_mode &= ~(SETBITS); 496 if (pmode) 497 set_pmode(arcn->name, arcn->sb.st_mode); 498 499 if (arcn->type == PAX_DIR) { 500 /* 501 * Dirs must be processed again at end of extract to set times 502 * and modes to agree with those stored in the archive. However 503 * to allow extract to continue, we may have to also set owner 504 * rights. This allows nodes in the archive that are children 505 * of this directory to be extracted without failure. Both time 506 * and modes will be fixed after the entire archive is read and 507 * before pax exits. 508 */ 509 if (access(arcn->name, R_OK | W_OK | X_OK) < 0) { 510 if (lstat(arcn->name, &sb) < 0) { 511 syswarn(0, errno,"Could not access %s (stat)", 512 arcn->name); 513 set_pmode(arcn->name,file_mode | S_IRWXU); 514 } else { 515 /* 516 * We have to add rights to the dir, so we make 517 * sure to restore the mode. The mode must be 518 * restored AS CREATED and not as stored if 519 * pmode is not set. 520 */ 521 set_pmode(arcn->name, 522 ((sb.st_mode & FILEBITS) | S_IRWXU)); 523 if (!pmode) 524 arcn->sb.st_mode = sb.st_mode; 525 } 526 527 /* 528 * we have to force the mode to what was set here, 529 * since we changed it from the default as created. 530 */ 531 add_dir(arcn->name, arcn->nlen, &(arcn->sb), 1); 532 } else if (pmode || patime || pmtime) 533 add_dir(arcn->name, arcn->nlen, &(arcn->sb), 0); 534 } 535 536 if (patime || pmtime) 537 set_ftime(arcn->name, arcn->sb.st_mtime, arcn->sb.st_atime, 0); 538 if (pfflags && arcn->type != PAX_SLK) 539 set_chflags(arcn->name, arcn->sb.st_flags); 540 return(0); 541} 542 543/* 544 * unlnk_exist() 545 * Remove node from file system with the specified name. We pass the type 546 * of the node that is going to replace it. When we try to create a 547 * directory and find that it already exists, we allow processing to 548 * continue as proper modes etc will always be set for it later on. 549 * Return: 550 * 0 is ok to proceed, no file with the specified name exists 551 * -1 we were unable to remove the node, or we should not remove it (-k) 552 * 1 we found a directory and we were going to create a directory. 553 */ 554 555#if __STDC__ 556int 557unlnk_exist(char *name, int type) 558#else 559int 560unlnk_exist(name, type) 561 char *name; 562 int type; 563#endif 564{ 565 struct stat sb; 566 567 /* 568 * the file does not exist, or -k we are done 569 */ 570 if (lstat(name, &sb) < 0) 571 return(0); 572 if (kflag) 573 return(-1); 574 575 if (S_ISDIR(sb.st_mode)) { 576 /* 577 * try to remove a directory, if it fails and we were going to 578 * create a directory anyway, tell the caller (return a 1) 579 */ 580 if (rmdir(name) < 0) { 581 if (type == PAX_DIR) 582 return(1); 583 syswarn(1,errno,"Unable to remove directory %s", name); 584 return(-1); 585 } 586 return(0); 587 } 588 589 /* 590 * try to get rid of all non-directory type nodes 591 */ 592 if (unlink(name) < 0) { 593 syswarn(1, errno, "Could not unlink %s", name); 594 return(-1); 595 } 596 return(0); 597} 598 599/* 600 * chk_path() 601 * We were trying to create some kind of node in the file system and it 602 * failed. chk_path() makes sure the path up to the node exists and is 603 * writeable. When we have to create a directory that is missing along the 604 * path somewhere, the directory we create will be set to the same 605 * uid/gid as the file has (when uid and gid are being preserved). 606 * NOTE: this routine is a real performance loss. It is only used as a 607 * last resort when trying to create entries in the file system. 608 * Return: 609 * -1 when it could find nothing it is allowed to fix. 610 * 0 otherwise 611 */ 612 613#if __STDC__ 614int 615chk_path( char *name, uid_t st_uid, gid_t st_gid) 616#else 617int 618chk_path(name, st_uid, st_gid) 619 char *name; 620 uid_t st_uid; 621 gid_t st_gid; 622#endif 623{ 624 char *spt = name; 625 struct stat sb; 626 int retval = -1; 627 628 /* 629 * watch out for paths with nodes stored directly in / (e.g. /bozo) 630 */ 631 if (*spt == '/') 632 ++spt; 633 634 for(;;) { 635 /* 636 * work foward from the first / and check each part of the path 637 */ 638 spt = strchr(spt, '/'); 639 if (spt == NULL) 640 break; 641 *spt = '\0'; 642 643 /* 644 * if it exists we assume it is a directory, it is not within 645 * the spec (at least it seems to read that way) to alter the 646 * file system for nodes NOT EXPLICITLY stored on the archive. 647 * If that assumption is changed, you would test the node here 648 * and figure out how to get rid of it (probably like some 649 * recursive unlink()) or fix up the directory permissions if 650 * required (do an access()). 651 */ 652 if (lstat(name, &sb) == 0) { 653 *(spt++) = '/'; 654 continue; 655 } 656 657 /* 658 * the path fails at this point, see if we can create the 659 * needed directory and continue on 660 */ 661 if (mkdir(name, S_IRWXU | S_IRWXG | S_IRWXO) < 0) { 662 *spt = '/'; 663 retval = -1; 664 break; 665 } 666 667 /* 668 * we were able to create the directory. We will tell the 669 * caller that we found something to fix, and it is ok to try 670 * and create the node again. 671 */ 672 retval = 0; 673 if (pids) 674 (void)set_ids(name, st_uid, st_gid); 675 676 /* 677 * make sure the user doen't have some strange umask that 678 * causes this newly created directory to be unusable. We fix 679 * the modes and restore them back to the creation default at 680 * the end of pax 681 */ 682 if ((access(name, R_OK | W_OK | X_OK) < 0) && 683 (lstat(name, &sb) == 0)) { 684 set_pmode(name, ((sb.st_mode & FILEBITS) | S_IRWXU)); 685 add_dir(name, spt - name, &sb, 1); 686 } 687 *(spt++) = '/'; 688 continue; 689 } 690 return(retval); 691} 692 693/* 694 * set_ftime() 695 * Set the access time and modification time for a named file. If frc is 696 * non-zero we force these times to be set even if the the user did not 697 * request access and/or modification time preservation (this is also 698 * used by -t to reset access times). 699 * When ign is zero, only those times the user has asked for are set, the 700 * other ones are left alone. We do not assume the un-documented feature 701 * of many utimes() implementations that consider a 0 time value as a do 702 * not set request. 703 */ 704 705#if __STDC__ 706void 707set_ftime(char *fnm, time_t mtime, time_t atime, int frc) 708#else 709void 710set_ftime(fnm, mtime, atime, frc) 711 char *fnm; 712 time_t mtime; 713 time_t atime; 714 int frc; 715#endif 716{ 717 struct timeval tv[2]; 718 struct stat sb; 719 720 tv[0].tv_sec = (long)atime; 721 tv[0].tv_usec = 0; 722 tv[1].tv_sec = (long)mtime; 723 tv[1].tv_usec = 0; 724 if (!frc && (!patime || !pmtime)) { 725 /* 726 * if we are not forcing, only set those times the user wants 727 * set. We get the current values of the times if we need them. 728 */ 729 if (lstat(fnm, &sb) == 0) { 730 if (!patime) 731 TIMESPEC_TO_TIMEVAL(&tv[0], &sb.st_atimespec); 732 if (!pmtime) 733 TIMESPEC_TO_TIMEVAL(&tv[1], &sb.st_mtimespec); 734 } else 735 syswarn(0,errno,"Unable to obtain file stats %s", fnm); 736 } 737 738 /* 739 * set the times 740 */ 741 if (lutimes(fnm, tv) < 0) 742 syswarn(1, errno, "Access/modification time set failed on: %s", 743 fnm); 744 return; 745} 746 747/* 748 * set_ids() 749 * set the uid and gid of a file system node 750 * Return: 751 * 0 when set, -1 on failure 752 */ 753 754#if __STDC__ 755int 756set_ids(char *fnm, uid_t uid, gid_t gid) 757#else 758int 759set_ids(fnm, uid, gid) 760 char *fnm; 761 uid_t uid; 762 gid_t gid; 763#endif 764{ 765 if (lchown(fnm, uid, gid) < 0) { 766 syswarn(1, errno, "Unable to set file uid/gid of %s", fnm); 767 return(-1); 768 } 769 return(0); 770} 771 772/* 773 * set_pmode() 774 * Set file access mode 775 */ 776 777#if __STDC__ 778void 779set_pmode(char *fnm, mode_t mode) 780#else 781void 782set_pmode(fnm, mode) 783 char *fnm; 784 mode_t mode; 785#endif 786{ 787 mode &= ABITS; 788 if (lchmod(fnm, mode) < 0) 789 syswarn(1, errno, "Could not set permissions on %s", fnm); 790 return; 791} 792 793/* 794 * set_chflags() 795 * Set 4.4BSD file flags 796 */ 797#if __STDC__ 798void 799set_chflags(char *fnm, u_int32_t flags) 800#else 801void 802set_chflags(fnm, flags) 803 char *fnm; 804 u_int32_t flags; 805#endif 806{ 807#if 0 808 if (chflags(fnm, flags) < 0) 809 syswarn(1, errno, "Could not set file flags on %s", fnm); 810#endif 811 return; 812} 813 814/* 815 * file_write() 816 * Write/copy a file (during copy or archive extract). This routine knows 817 * how to copy files with lseek holes in it. (Which are read as file 818 * blocks containing all 0's but do not have any file blocks associated 819 * with the data). Typical examples of these are files created by dbm 820 * variants (.pag files). While the file size of these files are huge, the 821 * actual storage is quite small (the files are sparse). The problem is 822 * the holes read as all zeros so are probably stored on the archive that 823 * way (there is no way to determine if the file block is really a hole, 824 * we only know that a file block of all zero's can be a hole). 825 * At this writing, no major archive format knows how to archive files 826 * with holes. However, on extraction (or during copy, -rw) we have to 827 * deal with these files. Without detecting the holes, the files can 828 * consume a lot of file space if just written to disk. This replacement 829 * for write when passed the basic allocation size of a file system block, 830 * uses lseek whenever it detects the input data is all 0 within that 831 * file block. In more detail, the strategy is as follows: 832 * While the input is all zero keep doing an lseek. Keep track of when we 833 * pass over file block boundries. Only write when we hit a non zero 834 * input. once we have written a file block, we continue to write it to 835 * the end (we stop looking at the input). When we reach the start of the 836 * next file block, start checking for zero blocks again. Working on file 837 * block boundries significantly reduces the overhead when copying files 838 * that are NOT very sparse. This overhead (when compared to a write) is 839 * almost below the measurement resolution on many systems. Without it, 840 * files with holes cannot be safely copied. It does has a side effect as 841 * it can put holes into files that did not have them before, but that is 842 * not a problem since the file contents are unchanged (in fact it saves 843 * file space). (Except on paging files for diskless clients. But since we 844 * cannot determine one of those file from here, we ignore them). If this 845 * ever ends up on a system where CTG files are supported and the holes 846 * are not desired, just do a conditional test in those routines that 847 * call file_write() and have it call write() instead. BEFORE CLOSING THE 848 * FILE, make sure to call file_flush() when the last write finishes with 849 * an empty block. A lot of file systems will not create an lseek hole at 850 * the end. In this case we drop a single 0 at the end to force the 851 * trailing 0's in the file. 852 * ---Parameters--- 853 * rem: how many bytes left in this file system block 854 * isempt: have we written to the file block yet (is it empty) 855 * sz: basic file block allocation size 856 * cnt: number of bytes on this write 857 * str: buffer to write 858 * Return: 859 * number of bytes written, -1 on write (or lseek) error. 860 */ 861 862#if __STDC__ 863int 864file_write(int fd, char *str, int cnt, int *rem, int *isempt, int sz, 865 char *name) 866#else 867int 868file_write(fd, str, cnt, rem, isempt, sz, name) 869 int fd; 870 char *str; 871 int cnt; 872 int *rem; 873 int *isempt; 874 int sz; 875 char *name; 876#endif 877{ 878 char *pt; 879 char *end; 880 int wcnt; 881 char *st = str; 882 883 /* 884 * while we have data to process 885 */ 886 while (cnt) { 887 if (!*rem) { 888 /* 889 * We are now at the start of file system block again 890 * (or what we think one is...). start looking for 891 * empty blocks again 892 */ 893 *isempt = 1; 894 *rem = sz; 895 } 896 897 /* 898 * only examine up to the end of the current file block or 899 * remaining characters to write, whatever is smaller 900 */ 901 wcnt = MIN(cnt, *rem); 902 cnt -= wcnt; 903 *rem -= wcnt; 904 if (*isempt) { 905 /* 906 * have not written to this block yet, so we keep 907 * looking for zero's 908 */ 909 pt = st; 910 end = st + wcnt; 911 912 /* 913 * look for a zero filled buffer 914 */ 915 while ((pt < end) && (*pt == '\0')) 916 ++pt; 917 918 if (pt == end) { 919 /* 920 * skip, buf is empty so far 921 */ 922 if (fd > -1 && 923 lseek(fd, (off_t)wcnt, SEEK_CUR) < 0) { 924 syswarn(1,errno,"File seek on %s", 925 name); 926 return(-1); 927 } 928 st = pt; 929 continue; 930 } 931 /* 932 * drat, the buf is not zero filled 933 */ 934 *isempt = 0; 935 } 936 937 /* 938 * have non-zero data in this file system block, have to write 939 */ 940 if (fd == -1) { 941 /* GNU hack */ 942 if (gnu_hack_string) 943 err(1, "WARNING! Major Internal Error! GNU hack Failing!"); 944 gnu_hack_string = malloc(wcnt + 1); 945 if (gnu_hack_string == NULL) { 946 tty_warn(1, "Out of memory"); 947 return(-1); 948 } 949 strncpy(gnu_hack_string, st, wcnt); 950 gnu_hack_string[wcnt] = 0; 951 } else if (xwrite(fd, st, wcnt) != wcnt) { 952 syswarn(1, errno, "Failed write to file %s", name); 953 return(-1); 954 } 955 st += wcnt; 956 } 957 return(st - str); 958} 959 960/* 961 * file_flush() 962 * when the last file block in a file is zero, many file systems will not 963 * let us create a hole at the end. To get the last block with zeros, we 964 * write the last BYTE with a zero (back up one byte and write a zero). 965 */ 966 967#if __STDC__ 968void 969file_flush(int fd, char *fname, int isempt) 970#else 971void 972file_flush(fd, fname, isempt) 973 int fd; 974 char *fname; 975 int isempt; 976#endif 977{ 978 static char blnk[] = "\0"; 979 980 /* 981 * silly test, but make sure we are only called when the last block is 982 * filled with all zeros. 983 */ 984 if (!isempt) 985 return; 986 987 /* 988 * move back one byte and write a zero 989 */ 990 if (lseek(fd, (off_t)-1, SEEK_CUR) < 0) { 991 syswarn(1, errno, "Failed seek on file %s", fname); 992 return; 993 } 994 995 if (write_with_restart(fd, blnk, 1) < 0) 996 syswarn(1, errno, "Failed write to file %s", fname); 997 return; 998} 999 1000/* 1001 * rdfile_close() 1002 * close a file we have been reading (to copy or archive). If we have to 1003 * reset access time (tflag) do so (the times are stored in arcn). 1004 */ 1005 1006#if __STDC__ 1007void 1008rdfile_close(ARCHD *arcn, int *fd) 1009#else 1010void 1011rdfile_close(arcn, fd) 1012 ARCHD *arcn; 1013 int *fd; 1014#endif 1015{ 1016 /* 1017 * make sure the file is open 1018 */ 1019 if (*fd < 0) 1020 return; 1021 1022 (void)close(*fd); 1023 *fd = -1; 1024 if (!tflag) 1025 return; 1026 1027 /* 1028 * user wants last access time reset 1029 */ 1030 set_ftime(arcn->org_name, arcn->sb.st_mtime, arcn->sb.st_atime, 1); 1031 return; 1032} 1033 1034/* 1035 * set_crc() 1036 * read a file to calculate its crc. This is a real drag. Archive formats 1037 * that have this, end up reading the file twice (we have to write the 1038 * header WITH the crc before writing the file contents. Oh well... 1039 * Return: 1040 * 0 if was able to calculate the crc, -1 otherwise 1041 */ 1042 1043#if __STDC__ 1044int 1045set_crc(ARCHD *arcn, int fd) 1046#else 1047int 1048set_crc(arcn, fd) 1049 ARCHD *arcn; 1050 int fd; 1051#endif 1052{ 1053 int i; 1054 int res; 1055 off_t cpcnt = 0L; 1056 u_long size; 1057 unsigned long crc = 0L; 1058 char tbuf[FILEBLK]; 1059 struct stat sb; 1060 1061 if (fd < 0) { 1062 /* 1063 * hmm, no fd, should never happen. well no crc then. 1064 */ 1065 arcn->crc = 0L; 1066 return(0); 1067 } 1068 1069 if ((size = (u_long)arcn->sb.st_blksize) > (u_long)sizeof(tbuf)) 1070 size = (u_long)sizeof(tbuf); 1071 1072 /* 1073 * read all the bytes we think that there are in the file. If the user 1074 * is trying to archive an active file, forget this file. 1075 */ 1076 for(;;) { 1077 if ((res = read(fd, tbuf, size)) <= 0) 1078 break; 1079 cpcnt += res; 1080 for (i = 0; i < res; ++i) 1081 crc += (tbuf[i] & 0xff); 1082 } 1083 1084 /* 1085 * safety check. we want to avoid archiving files that are active as 1086 * they can create inconsistant archive copies. 1087 */ 1088 if (cpcnt != arcn->sb.st_size) 1089 tty_warn(1, "File changed size %s", arcn->org_name); 1090 else if (fstat(fd, &sb) < 0) 1091 syswarn(1, errno, "Failed stat on %s", arcn->org_name); 1092 else if (arcn->sb.st_mtime != sb.st_mtime) 1093 tty_warn(1, "File %s was modified during read", arcn->org_name); 1094 else if (lseek(fd, (off_t)0L, SEEK_SET) < 0) 1095 syswarn(1, errno, "File rewind failed on: %s", arcn->org_name); 1096 else { 1097 arcn->crc = crc; 1098 return(0); 1099 } 1100 return(-1); 1101} 1102