file_subs.c revision 1.60
1/* $NetBSD: file_subs.c,v 1.60 2007/04/29 20:23:34 msaitoh 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. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36#if HAVE_NBTOOL_CONFIG_H 37#include "nbtool_config.h" 38#endif 39 40#include <sys/cdefs.h> 41#if !defined(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 1.60 2007/04/29 20:23:34 msaitoh 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 <fcntl.h> 55#include <string.h> 56#include <stdio.h> 57#include <ctype.h> 58#include <errno.h> 59#include <sys/uio.h> 60#include <stdlib.h> 61#include "pax.h" 62#include "extern.h" 63#include "options.h" 64 65char *xtmp_name; 66 67static int 68mk_link(char *,struct stat *,char *, int); 69 70static int warn_broken; 71 72/* 73 * routines that deal with file operations such as: creating, removing; 74 * and setting access modes, uid/gid and times of files 75 */ 76#define SET_BITS (S_ISUID | S_ISGID) 77#define FILE_BITS (S_IRWXU | S_IRWXG | S_IRWXO) 78#define A_BITS (FILE_BITS | SET_BITS | S_ISVTX) 79 80/* 81 * The S_ISVTX (sticky bit) can be set by non-superuser on directories 82 * but not other kinds of files. 83 */ 84#define FILEBITS(dir) ((dir) ? (FILE_BITS | S_ISVTX) : FILE_BITS) 85#define SETBITS(dir) ((dir) ? SET_BITS : (SET_BITS | S_ISVTX)) 86 87static mode_t 88apply_umask(mode_t mode) 89{ 90 static mode_t cached_umask; 91 static int cached_umask_valid; 92 93 if (!cached_umask_valid) { 94 cached_umask = umask(0); 95 umask(cached_umask); 96 cached_umask_valid = 1; 97 } 98 99 return mode & ~cached_umask; 100} 101 102/* 103 * file_creat() 104 * Create and open a file. 105 * Return: 106 * file descriptor or -1 for failure 107 */ 108 109int 110file_creat(ARCHD *arcn, int write_to_hardlink) 111{ 112 int fd = -1; 113 int oerrno; 114 115 /* 116 * Some horribly busted tar implementations, have directory nodes 117 * that end in a /, but they mark as files. Compensate for that 118 * by not creating a directory node at this point, but a file node, 119 * and not creating the temp file. 120 */ 121 if (arcn->nlen != 0 && arcn->name[arcn->nlen - 1] == '/') { 122 if (!warn_broken) { 123 tty_warn(0, "Archive was created with a broken tar;" 124 " file `%s' is a directory, but marked as plain.", 125 arcn->name); 126 warn_broken = 1; 127 } 128 return -1; 129 } 130 131 /* 132 * In "cpio" archives it's usually the last record of a set of 133 * hardlinks which includes the contents of the file. We cannot 134 * use a tempory file in that case because we couldn't link it 135 * with the existing other hardlinks after restoring the contents 136 * to it. And it's also useless to create the hardlink under a 137 * temporary name because the other hardlinks would have partial 138 * contents while restoring. 139 */ 140 if (write_to_hardlink) 141 return (open(arcn->name, O_TRUNC | O_EXCL | O_RDWR, 0)); 142 143 /* 144 * Create a temporary file name so that the file doesn't have partial 145 * contents while restoring. 146 */ 147 arcn->tmp_name = malloc(arcn->nlen + 8); 148 if (arcn->tmp_name == NULL) { 149 syswarn(1, errno, "Cannot malloc %d bytes", arcn->nlen + 8); 150 return -1; 151 } 152 if (xtmp_name != NULL) 153 abort(); 154 xtmp_name = arcn->tmp_name; 155 156 for (;;) { 157 /* 158 * try to create the temporary file we use to restore the 159 * contents info. if this fails, keep checking all the nodes 160 * in the path until chk_path() finds that it cannot fix 161 * anything further. if that happens we just give up. 162 */ 163 (void)snprintf(arcn->tmp_name, arcn->nlen + 8, "%s.XXXXXX", 164 arcn->name); 165 fd = mkstemp(arcn->tmp_name); 166 if (fd >= 0) 167 break; 168 oerrno = errno; 169 if (nodirs || chk_path(arcn->name,arcn->sb.st_uid,arcn->sb.st_gid) < 0) { 170 (void)fflush(listf); 171 syswarn(1, oerrno, "Cannot create %s", arcn->tmp_name); 172 xtmp_name = NULL; 173 free(arcn->tmp_name); 174 arcn->tmp_name = NULL; 175 return -1; 176 } 177 } 178 return fd; 179} 180 181/* 182 * file_close() 183 * Close file descriptor to a file just created by pax. Sets modes, 184 * ownership and times as required. 185 * Return: 186 * 0 for success, -1 for failure 187 */ 188 189void 190file_close(ARCHD *arcn, int fd) 191{ 192 char *tmp_name; 193 int res; 194 195 if (fd < 0) 196 return; 197 198 tmp_name = (arcn->tmp_name != NULL) ? arcn->tmp_name : arcn->name; 199 200 if (close(fd) < 0) 201 syswarn(0, errno, "Cannot close file descriptor on %s", 202 tmp_name); 203 204 /* 205 * set owner/groups first as this may strip off mode bits we want 206 * then set file permission modes. Then set file access and 207 * modification times. 208 */ 209 if (pids) 210 res = set_ids(tmp_name, arcn->sb.st_uid, arcn->sb.st_gid); 211 else 212 res = 0; 213 214 /* 215 * IMPORTANT SECURITY NOTE: 216 * if not preserving mode or we cannot set uid/gid, then PROHIBIT 217 * set uid/gid bits but restore the file modes (since mkstemp doesn't). 218 */ 219 if (!pmode || res) 220 arcn->sb.st_mode &= ~SETBITS(0); 221 if (pmode) 222 set_pmode(tmp_name, arcn->sb.st_mode); 223 else 224 set_pmode(tmp_name, 225 apply_umask((arcn->sb.st_mode & FILEBITS(0)))); 226 if (patime || pmtime) 227 set_ftime(tmp_name, arcn->sb.st_mtime, arcn->sb.st_atime, 0); 228 229 /* Did we write directly to the target file? */ 230 if (arcn->tmp_name == NULL) 231 return; 232 233 /* 234 * Finally, now the temp file is fully instantiated rename it to 235 * the desired file name. 236 */ 237 if (rename(tmp_name, arcn->name) < 0) { 238 syswarn(0, errno, "Cannot rename %s to %s", 239 tmp_name, arcn->name); 240 (void)unlink(tmp_name); 241 } 242 243#if HAVE_STRUCT_STAT_ST_FLAGS 244 if (pfflags && arcn->type != PAX_SLK) 245 set_chflags(arcn->name, arcn->sb.st_flags); 246#endif 247 248 free(arcn->tmp_name); 249 arcn->tmp_name = NULL; 250 xtmp_name = NULL; 251} 252 253/* 254 * lnk_creat() 255 * Create a hard link to arcn->ln_name from arcn->name. arcn->ln_name 256 * must exist; 257 * Return: 258 * 0 if ok, -1 otherwise 259 */ 260 261int 262lnk_creat(ARCHD *arcn, int *payload) 263{ 264 struct stat sb; 265 266 /* 267 * Check if this hardlink carries the "payload". In "cpio" archives 268 * it's usually the last record of a set of hardlinks which includes 269 * the contents of the file. 270 * 271 */ 272 *payload = S_ISREG(arcn->sb.st_mode) && 273 (arcn->sb.st_size > 0) && (arcn->sb.st_size <= arcn->skip); 274 275 /* 276 * We may be running as root, so we have to be sure that link target 277 * is not a directory, so we lstat and check 278 */ 279 if (lstat(arcn->ln_name, &sb) < 0) { 280 syswarn(1, errno, "Cannot link to %s from %s", arcn->ln_name, 281 arcn->name); 282 return -1; 283 } 284 285 if (S_ISDIR(sb.st_mode)) { 286 tty_warn(1, "A hard link to the directory %s is not allowed", 287 arcn->ln_name); 288 return -1; 289 } 290 291 return mk_link(arcn->ln_name, &sb, arcn->name, 0); 292} 293 294/* 295 * cross_lnk() 296 * Create a hard link to arcn->org_name from arcn->name. Only used in copy 297 * with the -l flag. No warning or error if this does not succeed (we will 298 * then just create the file) 299 * Return: 300 * 1 if copy() should try to create this file node 301 * 0 if cross_lnk() ok, -1 for fatal flaw (like linking to self). 302 */ 303 304int 305cross_lnk(ARCHD *arcn) 306{ 307 /* 308 * try to make a link to original file (-l flag in copy mode). make 309 * sure we do not try to link to directories in case we are running as 310 * root (and it might succeed). 311 */ 312 if (arcn->type == PAX_DIR) 313 return 1; 314 return mk_link(arcn->org_name, &(arcn->sb), arcn->name, 1); 315} 316 317/* 318 * chk_same() 319 * In copy mode if we are not trying to make hard links between the src 320 * and destinations, make sure we are not going to overwrite ourselves by 321 * accident. This slows things down a little, but we have to protect all 322 * those people who make typing errors. 323 * Return: 324 * 1 the target does not exist, go ahead and copy 325 * 0 skip it file exists (-k) or may be the same as source file 326 */ 327 328int 329chk_same(ARCHD *arcn) 330{ 331 struct stat sb; 332 333 /* 334 * if file does not exist, return. if file exists and -k, skip it 335 * quietly 336 */ 337 if (lstat(arcn->name, &sb) < 0) 338 return 1; 339 if (kflag) 340 return 0; 341 342 /* 343 * better make sure the user does not have src == dest by mistake 344 */ 345 if ((arcn->sb.st_dev == sb.st_dev) && (arcn->sb.st_ino == sb.st_ino)) { 346 tty_warn(1, "Unable to copy %s, file would overwrite itself", 347 arcn->name); 348 return 0; 349 } 350 return 1; 351} 352 353/* 354 * mk_link() 355 * try to make a hard link between two files. if ign set, we do not 356 * complain. 357 * Return: 358 * 0 if successful (or we are done with this file but no error, such as 359 * finding the from file exists and the user has set -k). 360 * 1 when ign was set to indicates we could not make the link but we 361 * should try to copy/extract the file as that might work (and is an 362 * allowed option). -1 an error occurred. 363 */ 364 365static int 366mk_link(char *to, struct stat *to_sb, char *from, int ign) 367{ 368 struct stat sb; 369 int oerrno; 370 371 /* 372 * if from file exists, it has to be unlinked to make the link. If the 373 * file exists and -k is set, skip it quietly 374 */ 375 if (lstat(from, &sb) == 0) { 376 if (kflag) 377 return 0; 378 379 /* 380 * make sure it is not the same file, protect the user 381 */ 382 if ((to_sb->st_dev==sb.st_dev)&&(to_sb->st_ino == sb.st_ino)) { 383 tty_warn(1, "Cannot link file %s to itself", to); 384 return -1; 385 } 386 387 /* 388 * try to get rid of the file, based on the type 389 */ 390 if (S_ISDIR(sb.st_mode) && strcmp(from, ".") != 0) { 391 if (rmdir(from) < 0) { 392 syswarn(1, errno, "Cannot remove %s", from); 393 return -1; 394 } 395 } else if (unlink(from) < 0) { 396 if (!ign) { 397 syswarn(1, errno, "Cannot remove %s", from); 398 return -1; 399 } 400 return 1; 401 } 402 } 403 404 /* 405 * from file is gone (or did not exist), try to make the hard link. 406 * if it fails, check the path and try it again (if chk_path() says to 407 * try again) 408 */ 409 for (;;) { 410 if (link(to, from) == 0) 411 break; 412 oerrno = errno; 413 if (chk_path(from, to_sb->st_uid, to_sb->st_gid) == 0) 414 continue; 415 if (!ign) { 416 syswarn(1, oerrno, "Cannot link to %s from %s", to, 417 from); 418 return -1; 419 } 420 return 1; 421 } 422 423 /* 424 * all right the link was made 425 */ 426 return 0; 427} 428 429/* 430 * node_creat() 431 * create an entry in the file system (other than a file or hard link). 432 * If successful, sets uid/gid modes and times as required. 433 * Return: 434 * 0 if ok, -1 otherwise 435 */ 436 437int 438node_creat(ARCHD *arcn) 439{ 440 int res; 441 int ign = 0; 442 int oerrno; 443 int pass = 0; 444 mode_t file_mode; 445 struct stat sb; 446 char target[MAXPATHLEN]; 447 char *nm = arcn->name; 448 int len; 449 450 /* 451 * create node based on type, if that fails try to unlink the node and 452 * try again. finally check the path and try again. As noted in the 453 * file and link creation routines, this method seems to exhibit the 454 * best performance in general use workloads. 455 */ 456 file_mode = arcn->sb.st_mode & FILEBITS(arcn->type == PAX_DIR); 457 458 for (;;) { 459 switch (arcn->type) { 460 case PAX_DIR: 461 /* 462 * If -h (or -L) was given in tar-mode, follow the 463 * potential symlink chain before trying to create the 464 * directory. 465 */ 466 if (strcmp(NM_TAR, argv0) == 0 && Lflag) { 467 while (lstat(nm, &sb) == 0 && 468 S_ISLNK(sb.st_mode)) { 469 len = readlink(nm, target, 470 sizeof target - 1); 471 if (len == -1) { 472 syswarn(0, errno, 473 "cannot follow symlink %s " 474 "in chain for %s", 475 nm, arcn->name); 476 res = -1; 477 goto badlink; 478 } 479 target[len] = '\0'; 480 nm = target; 481 } 482 } 483 res = domkdir(nm, file_mode); 484badlink: 485 if (ign) 486 res = 0; 487 break; 488 case PAX_CHR: 489 file_mode |= S_IFCHR; 490 res = mknod(nm, file_mode, arcn->sb.st_rdev); 491 break; 492 case PAX_BLK: 493 file_mode |= S_IFBLK; 494 res = mknod(nm, file_mode, arcn->sb.st_rdev); 495 break; 496 case PAX_FIF: 497 res = mkfifo(nm, file_mode); 498 break; 499 case PAX_SCK: 500 /* 501 * Skip sockets, operation has no meaning under BSD 502 */ 503 tty_warn(0, 504 "%s skipped. Sockets cannot be copied or extracted", 505 nm); 506 return (-1); 507 case PAX_SLK: 508 res = symlink(arcn->ln_name, nm); 509 break; 510 case PAX_CTG: 511 case PAX_HLK: 512 case PAX_HRG: 513 case PAX_REG: 514 default: 515 /* 516 * we should never get here 517 */ 518 tty_warn(0, "%s has an unknown file type, skipping", 519 nm); 520 return (-1); 521 } 522 523 /* 524 * if we were able to create the node break out of the loop, 525 * otherwise try to unlink the node and try again. if that 526 * fails check the full path and try a final time. 527 */ 528 if (res == 0) 529 break; 530 531 /* 532 * we failed to make the node 533 */ 534 oerrno = errno; 535 switch (pass++) { 536 case 0: 537 if ((ign = unlnk_exist(nm, arcn->type)) < 0) 538 return (-1); 539 continue; 540 541 case 1: 542 if (nodirs || 543 chk_path(nm, arcn->sb.st_uid, 544 arcn->sb.st_gid) < 0) { 545 syswarn(1, oerrno, "Cannot create %s", nm); 546 return (-1); 547 } 548 continue; 549 } 550 551 /* 552 * it must be a file that exists but we can't create or 553 * remove, but we must avoid the infinite loop. 554 */ 555 break; 556 } 557 558 /* 559 * we were able to create the node. set uid/gid, modes and times 560 */ 561 if (pids) 562 res = set_ids(nm, arcn->sb.st_uid, arcn->sb.st_gid); 563 else 564 res = 0; 565 566 /* 567 * IMPORTANT SECURITY NOTE: 568 * if not preserving mode or we cannot set uid/gid, then PROHIBIT any 569 * set uid/gid bits 570 */ 571 if (!pmode || res) 572 arcn->sb.st_mode &= ~SETBITS(arcn->type == PAX_DIR); 573 if (pmode) 574 set_pmode(arcn->name, arcn->sb.st_mode); 575 576 if (arcn->type == PAX_DIR && strcmp(NM_CPIO, argv0) != 0) { 577 /* 578 * Dirs must be processed again at end of extract to set times 579 * and modes to agree with those stored in the archive. However 580 * to allow extract to continue, we may have to also set owner 581 * rights. This allows nodes in the archive that are children 582 * of this directory to be extracted without failure. Both time 583 * and modes will be fixed after the entire archive is read and 584 * before pax exits. 585 */ 586 if (access(nm, R_OK | W_OK | X_OK) < 0) { 587 if (lstat(nm, &sb) < 0) { 588 syswarn(0, errno,"Cannot access %s (stat)", 589 arcn->name); 590 set_pmode(nm,file_mode | S_IRWXU); 591 } else { 592 /* 593 * We have to add rights to the dir, so we make 594 * sure to restore the mode. The mode must be 595 * restored AS CREATED and not as stored if 596 * pmode is not set. 597 */ 598 set_pmode(nm, ((sb.st_mode & 599 FILEBITS(arcn->type == PAX_DIR)) | 600 S_IRWXU)); 601 if (!pmode) 602 arcn->sb.st_mode = sb.st_mode; 603 } 604 605 /* 606 * we have to force the mode to what was set here, 607 * since we changed it from the default as created. 608 */ 609 add_dir(nm, arcn->nlen, &(arcn->sb), 1); 610 } else if (pmode || patime || pmtime) 611 add_dir(nm, arcn->nlen, &(arcn->sb), 0); 612 } 613 614#if HAVE_LUTIMES 615 if (patime || pmtime) 616#else 617 if ((patime || pmtime) && arcn->type != PAX_SLK) 618#endif 619 set_ftime(arcn->name, arcn->sb.st_mtime, arcn->sb.st_atime, 0); 620 621#if HAVE_STRUCT_STAT_ST_FLAGS 622 if (pfflags && arcn->type != PAX_SLK) 623 set_chflags(arcn->name, arcn->sb.st_flags); 624#endif 625 return 0; 626} 627 628/* 629 * unlnk_exist() 630 * Remove node from file system with the specified name. We pass the type 631 * of the node that is going to replace it. When we try to create a 632 * directory and find that it already exists, we allow processing to 633 * continue as proper modes etc will always be set for it later on. 634 * Return: 635 * 0 is ok to proceed, no file with the specified name exists 636 * -1 we were unable to remove the node, or we should not remove it (-k) 637 * 1 we found a directory and we were going to create a directory. 638 */ 639 640int 641unlnk_exist(char *name, int type) 642{ 643 struct stat sb; 644 645 /* 646 * the file does not exist, or -k we are done 647 */ 648 if (lstat(name, &sb) < 0) 649 return 0; 650 if (kflag) 651 return -1; 652 653 if (S_ISDIR(sb.st_mode)) { 654 /* 655 * try to remove a directory, if it fails and we were going to 656 * create a directory anyway, tell the caller (return a 1). 657 * 658 * don't try to remove the directory if the name is "." 659 * otherwise later file/directory creation fails. 660 */ 661 if (strcmp(name, ".") == 0) 662 return 1; 663 if (rmdir(name) < 0) { 664 if (type == PAX_DIR) 665 return 1; 666 syswarn(1, errno, "Cannot remove directory %s", name); 667 return -1; 668 } 669 return 0; 670 } 671 672 /* 673 * try to get rid of all non-directory type nodes 674 */ 675 if (unlink(name) < 0) { 676 (void)fflush(listf); 677 syswarn(1, errno, "Cannot unlink %s", name); 678 return -1; 679 } 680 return 0; 681} 682 683/* 684 * chk_path() 685 * We were trying to create some kind of node in the file system and it 686 * failed. chk_path() makes sure the path up to the node exists and is 687 * writable. When we have to create a directory that is missing along the 688 * path somewhere, the directory we create will be set to the same 689 * uid/gid as the file has (when uid and gid are being preserved). 690 * NOTE: this routine is a real performance loss. It is only used as a 691 * last resort when trying to create entries in the file system. 692 * Return: 693 * -1 when it could find nothing it is allowed to fix. 694 * 0 otherwise 695 */ 696 697int 698chk_path(char *name, uid_t st_uid, gid_t st_gid) 699{ 700 char *spt = name; 701 struct stat sb; 702 int retval = -1; 703 704 /* 705 * watch out for paths with nodes stored directly in / (e.g. /bozo) 706 */ 707 if (*spt == '/') 708 ++spt; 709 710 for(;;) { 711 /* 712 * work forward from the first / and check each part of 713 * the path 714 */ 715 spt = strchr(spt, '/'); 716 if (spt == NULL) 717 break; 718 *spt = '\0'; 719 720 /* 721 * if it exists we assume it is a directory, it is not within 722 * the spec (at least it seems to read that way) to alter the 723 * file system for nodes NOT EXPLICITLY stored on the archive. 724 * If that assumption is changed, you would test the node here 725 * and figure out how to get rid of it (probably like some 726 * recursive unlink()) or fix up the directory permissions if 727 * required (do an access()). 728 */ 729 if (lstat(name, &sb) == 0) { 730 *(spt++) = '/'; 731 continue; 732 } 733 734 /* 735 * the path fails at this point, see if we can create the 736 * needed directory and continue on 737 */ 738 if (domkdir(name, S_IRWXU | S_IRWXG | S_IRWXO) == -1) { 739 *spt = '/'; 740 retval = -1; 741 break; 742 } 743 744 /* 745 * we were able to create the directory. We will tell the 746 * caller that we found something to fix, and it is ok to try 747 * and create the node again. 748 */ 749 retval = 0; 750 if (pids) 751 (void)set_ids(name, st_uid, st_gid); 752 753 /* 754 * make sure the user doesn't have some strange umask that 755 * causes this newly created directory to be unusable. We fix 756 * the modes and restore them back to the creation default at 757 * the end of pax 758 */ 759 if ((access(name, R_OK | W_OK | X_OK) < 0) && 760 (lstat(name, &sb) == 0)) { 761 set_pmode(name, ((sb.st_mode & FILEBITS(0)) | 762 S_IRWXU)); 763 add_dir(name, spt - name, &sb, 1); 764 } 765 *(spt++) = '/'; 766 continue; 767 } 768 /* 769 * We perform one final check here, because if someone else 770 * created the directory in parallel with us, we might return 771 * the wrong error code, even if the directory exists now. 772 */ 773 if (retval == -1 && stat(name, &sb) == 0 && S_ISDIR(sb.st_mode)) 774 retval = 0; 775 return retval; 776} 777 778/* 779 * set_ftime() 780 * Set the access time and modification time for a named file. If frc 781 * is non-zero we force these times to be set even if the user did not 782 * request access and/or modification time preservation (this is also 783 * used by -t to reset access times). 784 * When ign is zero, only those times the user has asked for are set, the 785 * other ones are left alone. We do not assume the un-documented feature 786 * of many utimes() implementations that consider a 0 time value as a do 787 * not set request. 788 */ 789 790void 791set_ftime(char *fnm, time_t mtime, time_t atime, int frc) 792{ 793 struct timeval tv[2]; 794 struct stat sb; 795 796 tv[0].tv_sec = (long)atime; 797 tv[0].tv_usec = 0; 798 tv[1].tv_sec = (long)mtime; 799 tv[1].tv_usec = 0; 800 if (!frc && (!patime || !pmtime)) { 801 /* 802 * if we are not forcing, only set those times the user wants 803 * set. We get the current values of the times if we need them. 804 */ 805 if (lstat(fnm, &sb) == 0) { 806#if BSD4_4 && !HAVE_NBTOOL_CONFIG_H 807 if (!patime) 808 TIMESPEC_TO_TIMEVAL(&tv[0], &sb.st_atimespec); 809 if (!pmtime) 810 TIMESPEC_TO_TIMEVAL(&tv[1], &sb.st_mtimespec); 811#else 812 if (!patime) 813 tv[0].tv_sec = sb.st_atime; 814 if (!pmtime) 815 tv[1].tv_sec = sb.st_mtime; 816#endif 817 } else 818 syswarn(0, errno, "Cannot obtain file stats %s", fnm); 819 } 820 821 /* 822 * set the times 823 */ 824#if HAVE_LUTIMES 825 if (lutimes(fnm, tv)) 826#else 827 if (utimes(fnm, tv)) 828#endif 829 syswarn(1, errno, "Access/modification time set failed on: %s", 830 fnm); 831 return; 832} 833 834/* 835 * set_ids() 836 * set the uid and gid of a file system node 837 * Return: 838 * 0 when set, -1 on failure 839 */ 840 841int 842set_ids(char *fnm, uid_t uid, gid_t gid) 843{ 844 if (geteuid() == 0) 845 if (lchown(fnm, uid, gid)) { 846 (void)fflush(listf); 847 syswarn(1, errno, "Cannot set file uid/gid of %s", 848 fnm); 849 return -1; 850 } 851 return 0; 852} 853 854/* 855 * set_pmode() 856 * Set file access mode 857 */ 858 859void 860set_pmode(char *fnm, mode_t mode) 861{ 862 mode &= A_BITS; 863 if (lchmod(fnm, mode)) { 864 (void)fflush(listf); 865 syswarn(1, errno, "Cannot set permissions on %s", fnm); 866 } 867 return; 868} 869 870/* 871 * set_chflags() 872 * Set 4.4BSD file flags 873 */ 874void 875set_chflags(char *fnm, u_int32_t flags) 876{ 877 878#if 0 879 if (chflags(fnm, flags) < 0 && errno != EOPNOTSUPP) 880 syswarn(1, errno, "Cannot set file flags on %s", fnm); 881#endif 882 return; 883} 884 885/* 886 * file_write() 887 * Write/copy a file (during copy or archive extract). This routine knows 888 * how to copy files with lseek holes in it. (Which are read as file 889 * blocks containing all 0's but do not have any file blocks associated 890 * with the data). Typical examples of these are files created by dbm 891 * variants (.pag files). While the file size of these files are huge, the 892 * actual storage is quite small (the files are sparse). The problem is 893 * the holes read as all zeros so are probably stored on the archive that 894 * way (there is no way to determine if the file block is really a hole, 895 * we only know that a file block of all zero's can be a hole). 896 * At this writing, no major archive format knows how to archive files 897 * with holes. However, on extraction (or during copy, -rw) we have to 898 * deal with these files. Without detecting the holes, the files can 899 * consume a lot of file space if just written to disk. This replacement 900 * for write when passed the basic allocation size of a file system block, 901 * uses lseek whenever it detects the input data is all 0 within that 902 * file block. In more detail, the strategy is as follows: 903 * While the input is all zero keep doing an lseek. Keep track of when we 904 * pass over file block boundaries. Only write when we hit a non zero 905 * input. once we have written a file block, we continue to write it to 906 * the end (we stop looking at the input). When we reach the start of the 907 * next file block, start checking for zero blocks again. Working on file 908 * block boundaries significantly reduces the overhead when copying files 909 * that are NOT very sparse. This overhead (when compared to a write) is 910 * almost below the measurement resolution on many systems. Without it, 911 * files with holes cannot be safely copied. It does has a side effect as 912 * it can put holes into files that did not have them before, but that is 913 * not a problem since the file contents are unchanged (in fact it saves 914 * file space). (Except on paging files for diskless clients. But since we 915 * cannot determine one of those file from here, we ignore them). If this 916 * ever ends up on a system where CTG files are supported and the holes 917 * are not desired, just do a conditional test in those routines that 918 * call file_write() and have it call write() instead. BEFORE CLOSING THE 919 * FILE, make sure to call file_flush() when the last write finishes with 920 * an empty block. A lot of file systems will not create an lseek hole at 921 * the end. In this case we drop a single 0 at the end to force the 922 * trailing 0's in the file. 923 * ---Parameters--- 924 * rem: how many bytes left in this file system block 925 * isempt: have we written to the file block yet (is it empty) 926 * sz: basic file block allocation size 927 * cnt: number of bytes on this write 928 * str: buffer to write 929 * Return: 930 * number of bytes written, -1 on write (or lseek) error. 931 */ 932 933int 934file_write(int fd, char *str, int cnt, int *rem, int *isempt, int sz, 935 char *name) 936{ 937 char *pt; 938 char *end; 939 int wcnt; 940 char *st = str; 941 char **strp; 942 size_t *lenp; 943 944 /* 945 * while we have data to process 946 */ 947 while (cnt) { 948 if (!*rem) { 949 /* 950 * We are now at the start of file system block again 951 * (or what we think one is...). start looking for 952 * empty blocks again 953 */ 954 *isempt = 1; 955 *rem = sz; 956 } 957 958 /* 959 * only examine up to the end of the current file block or 960 * remaining characters to write, whatever is smaller 961 */ 962 wcnt = MIN(cnt, *rem); 963 cnt -= wcnt; 964 *rem -= wcnt; 965 if (*isempt) { 966 /* 967 * have not written to this block yet, so we keep 968 * looking for zero's 969 */ 970 pt = st; 971 end = st + wcnt; 972 973 /* 974 * look for a zero filled buffer 975 */ 976 while ((pt < end) && (*pt == '\0')) 977 ++pt; 978 979 if (pt == end) { 980 /* 981 * skip, buf is empty so far 982 */ 983 if (fd > -1 && 984 lseek(fd, (off_t)wcnt, SEEK_CUR) < 0) { 985 syswarn(1, errno, "File seek on %s", 986 name); 987 return -1; 988 } 989 st = pt; 990 continue; 991 } 992 /* 993 * drat, the buf is not zero filled 994 */ 995 *isempt = 0; 996 } 997 998 /* 999 * have non-zero data in this file system block, have to write 1000 */ 1001 switch (fd) { 1002 case -PAX_GLF: 1003 strp = &gnu_name_string; 1004 lenp = &gnu_name_length; 1005 break; 1006 case -PAX_GLL: 1007 strp = &gnu_link_string; 1008 lenp = &gnu_link_length; 1009 break; 1010 default: 1011 strp = NULL; 1012 lenp = NULL; 1013 break; 1014 } 1015 if (strp) { 1016 char *nstr = *strp ? realloc(*strp, *lenp + wcnt + 1) : 1017 malloc(wcnt + 1); 1018 if (nstr == NULL) { 1019 tty_warn(1, "Out of memory"); 1020 return -1; 1021 } 1022 (void)strlcpy(&nstr[*lenp], st, wcnt + 1); 1023 *strp = nstr; 1024 *lenp += wcnt; 1025 } else if (xwrite(fd, st, wcnt) != wcnt) { 1026 syswarn(1, errno, "Failed write to file %s", name); 1027 return -1; 1028 } 1029 st += wcnt; 1030 } 1031 return st - str; 1032} 1033 1034/* 1035 * file_flush() 1036 * when the last file block in a file is zero, many file systems will not 1037 * let us create a hole at the end. To get the last block with zeros, we 1038 * write the last BYTE with a zero (back up one byte and write a zero). 1039 */ 1040 1041void 1042file_flush(int fd, char *fname, int isempt) 1043{ 1044 static char blnk[] = "\0"; 1045 1046 /* 1047 * silly test, but make sure we are only called when the last block is 1048 * filled with all zeros. 1049 */ 1050 if (!isempt) 1051 return; 1052 1053 /* 1054 * move back one byte and write a zero 1055 */ 1056 if (lseek(fd, (off_t)-1, SEEK_CUR) < 0) { 1057 syswarn(1, errno, "Failed seek on file %s", fname); 1058 return; 1059 } 1060 1061 if (write_with_restart(fd, blnk, 1) < 0) 1062 syswarn(1, errno, "Failed write to file %s", fname); 1063 return; 1064} 1065 1066/* 1067 * rdfile_close() 1068 * close a file we have been reading (to copy or archive). If we have to 1069 * reset access time (tflag) do so (the times are stored in arcn). 1070 */ 1071 1072void 1073rdfile_close(ARCHD *arcn, int *fd) 1074{ 1075 /* 1076 * make sure the file is open 1077 */ 1078 if (*fd < 0) 1079 return; 1080 1081 (void)close(*fd); 1082 *fd = -1; 1083 if (!tflag) 1084 return; 1085 1086 /* 1087 * user wants last access time reset 1088 */ 1089 set_ftime(arcn->org_name, arcn->sb.st_mtime, arcn->sb.st_atime, 1); 1090 return; 1091} 1092 1093/* 1094 * set_crc() 1095 * read a file to calculate its crc. This is a real drag. Archive formats 1096 * that have this, end up reading the file twice (we have to write the 1097 * header WITH the crc before writing the file contents. Oh well... 1098 * Return: 1099 * 0 if was able to calculate the crc, -1 otherwise 1100 */ 1101 1102int 1103set_crc(ARCHD *arcn, int fd) 1104{ 1105 int i; 1106 int res; 1107 off_t cpcnt = 0L; 1108 u_long size; 1109 unsigned long crc = 0L; 1110 char tbuf[FILEBLK]; 1111 struct stat sb; 1112 1113 if (fd < 0) { 1114 /* 1115 * hmm, no fd, should never happen. well no crc then. 1116 */ 1117 arcn->crc = 0L; 1118 return 0; 1119 } 1120 1121 if ((size = (u_long)arcn->sb.st_blksize) > (u_long)sizeof(tbuf)) 1122 size = (u_long)sizeof(tbuf); 1123 1124 /* 1125 * read all the bytes we think that there are in the file. If the user 1126 * is trying to archive an active file, forget this file. 1127 */ 1128 for(;;) { 1129 if ((res = read(fd, tbuf, size)) <= 0) 1130 break; 1131 cpcnt += res; 1132 for (i = 0; i < res; ++i) 1133 crc += (tbuf[i] & 0xff); 1134 } 1135 1136 /* 1137 * safety check. we want to avoid archiving files that are active as 1138 * they can create inconsistent archive copies. 1139 */ 1140 if (cpcnt != arcn->sb.st_size) 1141 tty_warn(1, "File changed size %s", arcn->org_name); 1142 else if (fstat(fd, &sb) < 0) 1143 syswarn(1, errno, "Failed stat on %s", arcn->org_name); 1144 else if (arcn->sb.st_mtime != sb.st_mtime) 1145 tty_warn(1, "File %s was modified during read", arcn->org_name); 1146 else if (lseek(fd, (off_t)0L, SEEK_SET) < 0) 1147 syswarn(1, errno, "File rewind failed on: %s", arcn->org_name); 1148 else { 1149 arcn->crc = crc; 1150 return 0; 1151 } 1152 return -1; 1153} 1154