file_subs.c revision 1.61
1/* $NetBSD: file_subs.c,v 1.61 2008/01/10 04:24:51 tls 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 1.61 2008/01/10 04:24:51 tls 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, 228 arcn->sb.st_atime, 0, 0); 229 230 /* Did we write directly to the target file? */ 231 if (arcn->tmp_name == NULL) 232 return; 233 234 /* 235 * Finally, now the temp file is fully instantiated rename it to 236 * the desired file name. 237 */ 238 if (rename(tmp_name, arcn->name) < 0) { 239 syswarn(0, errno, "Cannot rename %s to %s", 240 tmp_name, arcn->name); 241 (void)unlink(tmp_name); 242 } 243 244#if HAVE_STRUCT_STAT_ST_FLAGS 245 if (pfflags && arcn->type != PAX_SLK) 246 set_chflags(arcn->name, arcn->sb.st_flags); 247#endif 248 249 free(arcn->tmp_name); 250 arcn->tmp_name = NULL; 251 xtmp_name = NULL; 252} 253 254/* 255 * lnk_creat() 256 * Create a hard link to arcn->ln_name from arcn->name. arcn->ln_name 257 * must exist; 258 * Return: 259 * 0 if ok, -1 otherwise 260 */ 261 262int 263lnk_creat(ARCHD *arcn, int *payload) 264{ 265 struct stat sb; 266 267 /* 268 * Check if this hardlink carries the "payload". In "cpio" archives 269 * it's usually the last record of a set of hardlinks which includes 270 * the contents of the file. 271 * 272 */ 273 *payload = S_ISREG(arcn->sb.st_mode) && 274 (arcn->sb.st_size > 0) && (arcn->sb.st_size <= arcn->skip); 275 276 /* 277 * We may be running as root, so we have to be sure that link target 278 * is not a directory, so we lstat and check 279 */ 280 if (lstat(arcn->ln_name, &sb) < 0) { 281 syswarn(1, errno, "Cannot link to %s from %s", arcn->ln_name, 282 arcn->name); 283 return -1; 284 } 285 286 if (S_ISDIR(sb.st_mode)) { 287 tty_warn(1, "A hard link to the directory %s is not allowed", 288 arcn->ln_name); 289 return -1; 290 } 291 292 return mk_link(arcn->ln_name, &sb, arcn->name, 0); 293} 294 295/* 296 * cross_lnk() 297 * Create a hard link to arcn->org_name from arcn->name. Only used in copy 298 * with the -l flag. No warning or error if this does not succeed (we will 299 * then just create the file) 300 * Return: 301 * 1 if copy() should try to create this file node 302 * 0 if cross_lnk() ok, -1 for fatal flaw (like linking to self). 303 */ 304 305int 306cross_lnk(ARCHD *arcn) 307{ 308 /* 309 * try to make a link to original file (-l flag in copy mode). make 310 * sure we do not try to link to directories in case we are running as 311 * root (and it might succeed). 312 */ 313 if (arcn->type == PAX_DIR) 314 return 1; 315 return mk_link(arcn->org_name, &(arcn->sb), arcn->name, 1); 316} 317 318/* 319 * chk_same() 320 * In copy mode if we are not trying to make hard links between the src 321 * and destinations, make sure we are not going to overwrite ourselves by 322 * accident. This slows things down a little, but we have to protect all 323 * those people who make typing errors. 324 * Return: 325 * 1 the target does not exist, go ahead and copy 326 * 0 skip it file exists (-k) or may be the same as source file 327 */ 328 329int 330chk_same(ARCHD *arcn) 331{ 332 struct stat sb; 333 334 /* 335 * if file does not exist, return. if file exists and -k, skip it 336 * quietly 337 */ 338 if (lstat(arcn->name, &sb) < 0) 339 return 1; 340 if (kflag) 341 return 0; 342 343 /* 344 * better make sure the user does not have src == dest by mistake 345 */ 346 if ((arcn->sb.st_dev == sb.st_dev) && (arcn->sb.st_ino == sb.st_ino)) { 347 tty_warn(1, "Unable to copy %s, file would overwrite itself", 348 arcn->name); 349 return 0; 350 } 351 return 1; 352} 353 354/* 355 * mk_link() 356 * try to make a hard link between two files. if ign set, we do not 357 * complain. 358 * Return: 359 * 0 if successful (or we are done with this file but no error, such as 360 * finding the from file exists and the user has set -k). 361 * 1 when ign was set to indicates we could not make the link but we 362 * should try to copy/extract the file as that might work (and is an 363 * allowed option). -1 an error occurred. 364 */ 365 366static int 367mk_link(char *to, struct stat *to_sb, char *from, int ign) 368{ 369 struct stat sb; 370 int oerrno; 371 372 /* 373 * if from file exists, it has to be unlinked to make the link. If the 374 * file exists and -k is set, skip it quietly 375 */ 376 if (lstat(from, &sb) == 0) { 377 if (kflag) 378 return 0; 379 380 /* 381 * make sure it is not the same file, protect the user 382 */ 383 if ((to_sb->st_dev==sb.st_dev)&&(to_sb->st_ino == sb.st_ino)) { 384 tty_warn(1, "Cannot link file %s to itself", to); 385 return -1; 386 } 387 388 /* 389 * try to get rid of the file, based on the type 390 */ 391 if (S_ISDIR(sb.st_mode) && strcmp(from, ".") != 0) { 392 if (rmdir(from) < 0) { 393 syswarn(1, errno, "Cannot remove %s", from); 394 return -1; 395 } 396 } else if (unlink(from) < 0) { 397 if (!ign) { 398 syswarn(1, errno, "Cannot remove %s", from); 399 return -1; 400 } 401 return 1; 402 } 403 } 404 405 /* 406 * from file is gone (or did not exist), try to make the hard link. 407 * if it fails, check the path and try it again (if chk_path() says to 408 * try again) 409 */ 410 for (;;) { 411 if (link(to, from) == 0) 412 break; 413 oerrno = errno; 414 if (chk_path(from, to_sb->st_uid, to_sb->st_gid) == 0) 415 continue; 416 if (!ign) { 417 syswarn(1, oerrno, "Cannot link to %s from %s", to, 418 from); 419 return -1; 420 } 421 return 1; 422 } 423 424 /* 425 * all right the link was made 426 */ 427 return 0; 428} 429 430/* 431 * node_creat() 432 * create an entry in the file system (other than a file or hard link). 433 * If successful, sets uid/gid modes and times as required. 434 * Return: 435 * 0 if ok, -1 otherwise 436 */ 437 438int 439node_creat(ARCHD *arcn) 440{ 441 int res; 442 int ign = 0; 443 int oerrno; 444 int pass = 0; 445 mode_t file_mode; 446 struct stat sb; 447 char target[MAXPATHLEN]; 448 char *nm = arcn->name; 449 int len; 450 451 /* 452 * create node based on type, if that fails try to unlink the node and 453 * try again. finally check the path and try again. As noted in the 454 * file and link creation routines, this method seems to exhibit the 455 * best performance in general use workloads. 456 */ 457 file_mode = arcn->sb.st_mode & FILEBITS(arcn->type == PAX_DIR); 458 459 for (;;) { 460 switch (arcn->type) { 461 case PAX_DIR: 462 /* 463 * If -h (or -L) was given in tar-mode, follow the 464 * potential symlink chain before trying to create the 465 * directory. 466 */ 467 if (strcmp(NM_TAR, argv0) == 0 && Lflag) { 468 while (lstat(nm, &sb) == 0 && 469 S_ISLNK(sb.st_mode)) { 470 len = readlink(nm, target, 471 sizeof target - 1); 472 if (len == -1) { 473 syswarn(0, errno, 474 "cannot follow symlink %s " 475 "in chain for %s", 476 nm, arcn->name); 477 res = -1; 478 goto badlink; 479 } 480 target[len] = '\0'; 481 nm = target; 482 } 483 } 484 res = domkdir(nm, file_mode); 485badlink: 486 if (ign) 487 res = 0; 488 break; 489 case PAX_CHR: 490 file_mode |= S_IFCHR; 491 res = mknod(nm, file_mode, arcn->sb.st_rdev); 492 break; 493 case PAX_BLK: 494 file_mode |= S_IFBLK; 495 res = mknod(nm, file_mode, arcn->sb.st_rdev); 496 break; 497 case PAX_FIF: 498 res = mkfifo(nm, file_mode); 499 break; 500 case PAX_SCK: 501 /* 502 * Skip sockets, operation has no meaning under BSD 503 */ 504 tty_warn(0, 505 "%s skipped. Sockets cannot be copied or extracted", 506 nm); 507 return (-1); 508 case PAX_SLK: 509 res = symlink(arcn->ln_name, nm); 510 break; 511 case PAX_CTG: 512 case PAX_HLK: 513 case PAX_HRG: 514 case PAX_REG: 515 default: 516 /* 517 * we should never get here 518 */ 519 tty_warn(0, "%s has an unknown file type, skipping", 520 nm); 521 return (-1); 522 } 523 524 /* 525 * if we were able to create the node break out of the loop, 526 * otherwise try to unlink the node and try again. if that 527 * fails check the full path and try a final time. 528 */ 529 if (res == 0) 530 break; 531 532 /* 533 * we failed to make the node 534 */ 535 oerrno = errno; 536 switch (pass++) { 537 case 0: 538 if ((ign = unlnk_exist(nm, arcn->type)) < 0) 539 return (-1); 540 continue; 541 542 case 1: 543 if (nodirs || 544 chk_path(nm, arcn->sb.st_uid, 545 arcn->sb.st_gid) < 0) { 546 syswarn(1, oerrno, "Cannot create %s", nm); 547 return (-1); 548 } 549 continue; 550 } 551 552 /* 553 * it must be a file that exists but we can't create or 554 * remove, but we must avoid the infinite loop. 555 */ 556 break; 557 } 558 559 /* 560 * we were able to create the node. set uid/gid, modes and times 561 */ 562 if (pids) 563 res = set_ids(nm, arcn->sb.st_uid, arcn->sb.st_gid); 564 else 565 res = 0; 566 567 /* 568 * IMPORTANT SECURITY NOTE: 569 * if not preserving mode or we cannot set uid/gid, then PROHIBIT any 570 * set uid/gid bits 571 */ 572 if (!pmode || res) 573 arcn->sb.st_mode &= ~SETBITS(arcn->type == PAX_DIR); 574 if (pmode) 575 set_pmode(arcn->name, arcn->sb.st_mode); 576 577 if (arcn->type == PAX_DIR && strcmp(NM_CPIO, argv0) != 0) { 578 /* 579 * Dirs must be processed again at end of extract to set times 580 * and modes to agree with those stored in the archive. However 581 * to allow extract to continue, we may have to also set owner 582 * rights. This allows nodes in the archive that are children 583 * of this directory to be extracted without failure. Both time 584 * and modes will be fixed after the entire archive is read and 585 * before pax exits. 586 */ 587 if (access(nm, R_OK | W_OK | X_OK) < 0) { 588 if (lstat(nm, &sb) < 0) { 589 syswarn(0, errno,"Cannot access %s (stat)", 590 arcn->name); 591 set_pmode(nm,file_mode | S_IRWXU); 592 } else { 593 /* 594 * We have to add rights to the dir, so we make 595 * sure to restore the mode. The mode must be 596 * restored AS CREATED and not as stored if 597 * pmode is not set. 598 */ 599 set_pmode(nm, ((sb.st_mode & 600 FILEBITS(arcn->type == PAX_DIR)) | 601 S_IRWXU)); 602 if (!pmode) 603 arcn->sb.st_mode = sb.st_mode; 604 } 605 606 /* 607 * we have to force the mode to what was set here, 608 * since we changed it from the default as created. 609 */ 610 add_dir(nm, arcn->nlen, &(arcn->sb), 1); 611 } else if (pmode || patime || pmtime) 612 add_dir(nm, arcn->nlen, &(arcn->sb), 0); 613 } 614 615 if (patime || pmtime) 616 set_ftime(arcn->name, arcn->sb.st_mtime, 617 arcn->sb.st_atime, 0, (arcn->type == PAX_SLK) ? 1 : 0); 618 619#if HAVE_STRUCT_STAT_ST_FLAGS 620 if (pfflags && arcn->type != PAX_SLK) 621 set_chflags(arcn->name, arcn->sb.st_flags); 622#endif 623 return 0; 624} 625 626/* 627 * unlnk_exist() 628 * Remove node from file system with the specified name. We pass the type 629 * of the node that is going to replace it. When we try to create a 630 * directory and find that it already exists, we allow processing to 631 * continue as proper modes etc will always be set for it later on. 632 * Return: 633 * 0 is ok to proceed, no file with the specified name exists 634 * -1 we were unable to remove the node, or we should not remove it (-k) 635 * 1 we found a directory and we were going to create a directory. 636 */ 637 638int 639unlnk_exist(char *name, int type) 640{ 641 struct stat sb; 642 643 /* 644 * the file does not exist, or -k we are done 645 */ 646 if (lstat(name, &sb) < 0) 647 return 0; 648 if (kflag) 649 return -1; 650 651 if (S_ISDIR(sb.st_mode)) { 652 /* 653 * try to remove a directory, if it fails and we were going to 654 * create a directory anyway, tell the caller (return a 1). 655 * 656 * don't try to remove the directory if the name is "." 657 * otherwise later file/directory creation fails. 658 */ 659 if (strcmp(name, ".") == 0) 660 return 1; 661 if (rmdir(name) < 0) { 662 if (type == PAX_DIR) 663 return 1; 664 syswarn(1, errno, "Cannot remove directory %s", name); 665 return -1; 666 } 667 return 0; 668 } 669 670 /* 671 * try to get rid of all non-directory type nodes 672 */ 673 if (unlink(name) < 0) { 674 (void)fflush(listf); 675 syswarn(1, errno, "Cannot unlink %s", name); 676 return -1; 677 } 678 return 0; 679} 680 681/* 682 * chk_path() 683 * We were trying to create some kind of node in the file system and it 684 * failed. chk_path() makes sure the path up to the node exists and is 685 * writable. When we have to create a directory that is missing along the 686 * path somewhere, the directory we create will be set to the same 687 * uid/gid as the file has (when uid and gid are being preserved). 688 * NOTE: this routine is a real performance loss. It is only used as a 689 * last resort when trying to create entries in the file system. 690 * Return: 691 * -1 when it could find nothing it is allowed to fix. 692 * 0 otherwise 693 */ 694 695int 696chk_path(char *name, uid_t st_uid, gid_t st_gid) 697{ 698 char *spt = name; 699 struct stat sb; 700 int retval = -1; 701 702 /* 703 * watch out for paths with nodes stored directly in / (e.g. /bozo) 704 */ 705 if (*spt == '/') 706 ++spt; 707 708 for(;;) { 709 /* 710 * work forward from the first / and check each part of 711 * the path 712 */ 713 spt = strchr(spt, '/'); 714 if (spt == NULL) 715 break; 716 *spt = '\0'; 717 718 /* 719 * if it exists we assume it is a directory, it is not within 720 * the spec (at least it seems to read that way) to alter the 721 * file system for nodes NOT EXPLICITLY stored on the archive. 722 * If that assumption is changed, you would test the node here 723 * and figure out how to get rid of it (probably like some 724 * recursive unlink()) or fix up the directory permissions if 725 * required (do an access()). 726 */ 727 if (lstat(name, &sb) == 0) { 728 *(spt++) = '/'; 729 continue; 730 } 731 732 /* 733 * the path fails at this point, see if we can create the 734 * needed directory and continue on 735 */ 736 if (domkdir(name, S_IRWXU | S_IRWXG | S_IRWXO) == -1) { 737 *spt = '/'; 738 retval = -1; 739 break; 740 } 741 742 /* 743 * we were able to create the directory. We will tell the 744 * caller that we found something to fix, and it is ok to try 745 * and create the node again. 746 */ 747 retval = 0; 748 if (pids) 749 (void)set_ids(name, st_uid, st_gid); 750 751 /* 752 * make sure the user doesn't have some strange umask that 753 * causes this newly created directory to be unusable. We fix 754 * the modes and restore them back to the creation default at 755 * the end of pax 756 */ 757 if ((access(name, R_OK | W_OK | X_OK) < 0) && 758 (lstat(name, &sb) == 0)) { 759 set_pmode(name, ((sb.st_mode & FILEBITS(0)) | 760 S_IRWXU)); 761 add_dir(name, spt - name, &sb, 1); 762 } 763 *(spt++) = '/'; 764 continue; 765 } 766 /* 767 * We perform one final check here, because if someone else 768 * created the directory in parallel with us, we might return 769 * the wrong error code, even if the directory exists now. 770 */ 771 if (retval == -1 && stat(name, &sb) == 0 && S_ISDIR(sb.st_mode)) 772 retval = 0; 773 return retval; 774} 775 776/* 777 * set_ftime() 778 * Set the access time and modification time for a named file. If frc 779 * is non-zero we force these times to be set even if the user did not 780 * request access and/or modification time preservation (this is also 781 * used by -t to reset access times). 782 * When ign is zero, only those times the user has asked for are set, the 783 * other ones are left alone. We do not assume the un-documented feature 784 * of many utimes() implementations that consider a 0 time value as a do 785 * not set request. 786 * 787 * Unfortunately, there are systems where lutimes() is present but does 788 * not work on some filesystem types, which cannot be detected at 789 * compile time. This requires passing down symlink knowledge into 790 * this function to obtain correct operation. Linux with XFS is one 791 * example of such a system. 792 */ 793 794void 795set_ftime(char *fnm, time_t mtime, time_t atime, int frc, int slk) 796{ 797 struct timeval tv[2]; 798 struct stat sb; 799 800 tv[0].tv_sec = (long)atime; 801 tv[0].tv_usec = 0; 802 tv[1].tv_sec = (long)mtime; 803 tv[1].tv_usec = 0; 804 if (!frc && (!patime || !pmtime)) { 805 /* 806 * if we are not forcing, only set those times the user wants 807 * set. We get the current values of the times if we need them. 808 */ 809 if (lstat(fnm, &sb) == 0) { 810#if BSD4_4 && !HAVE_NBTOOL_CONFIG_H 811 if (!patime) 812 TIMESPEC_TO_TIMEVAL(&tv[0], &sb.st_atimespec); 813 if (!pmtime) 814 TIMESPEC_TO_TIMEVAL(&tv[1], &sb.st_mtimespec); 815#else 816 if (!patime) 817 tv[0].tv_sec = sb.st_atime; 818 if (!pmtime) 819 tv[1].tv_sec = sb.st_mtime; 820#endif 821 } else 822 syswarn(0, errno, "Cannot obtain file stats %s", fnm); 823 } 824 825 /* 826 * set the times 827 */ 828#if HAVE_LUTIMES 829 if (lutimes(fnm, tv) == 0) 830 return; 831 if (errno != ENOSYS) /* XXX linux: lutimes is per-FS */ 832 goto bad; 833#endif 834 if (slk) 835 return; 836 if (utimes(fnm, tv) == -1) 837 goto bad; 838 return; 839bad: 840 syswarn(1, errno, "Access/modification time set failed on: %s", fnm); 841} 842 843/* 844 * set_ids() 845 * set the uid and gid of a file system node 846 * Return: 847 * 0 when set, -1 on failure 848 */ 849 850int 851set_ids(char *fnm, uid_t uid, gid_t gid) 852{ 853 if (geteuid() == 0) 854 if (lchown(fnm, uid, gid)) { 855 (void)fflush(listf); 856 syswarn(1, errno, "Cannot set file uid/gid of %s", 857 fnm); 858 return -1; 859 } 860 return 0; 861} 862 863/* 864 * set_pmode() 865 * Set file access mode 866 */ 867 868void 869set_pmode(char *fnm, mode_t mode) 870{ 871 mode &= A_BITS; 872 if (lchmod(fnm, mode)) { 873 (void)fflush(listf); 874 syswarn(1, errno, "Cannot set permissions on %s", fnm); 875 } 876 return; 877} 878 879/* 880 * set_chflags() 881 * Set 4.4BSD file flags 882 */ 883void 884set_chflags(char *fnm, u_int32_t flags) 885{ 886 887#if 0 888 if (chflags(fnm, flags) < 0 && errno != EOPNOTSUPP) 889 syswarn(1, errno, "Cannot set file flags on %s", fnm); 890#endif 891 return; 892} 893 894/* 895 * file_write() 896 * Write/copy a file (during copy or archive extract). This routine knows 897 * how to copy files with lseek holes in it. (Which are read as file 898 * blocks containing all 0's but do not have any file blocks associated 899 * with the data). Typical examples of these are files created by dbm 900 * variants (.pag files). While the file size of these files are huge, the 901 * actual storage is quite small (the files are sparse). The problem is 902 * the holes read as all zeros so are probably stored on the archive that 903 * way (there is no way to determine if the file block is really a hole, 904 * we only know that a file block of all zero's can be a hole). 905 * At this writing, no major archive format knows how to archive files 906 * with holes. However, on extraction (or during copy, -rw) we have to 907 * deal with these files. Without detecting the holes, the files can 908 * consume a lot of file space if just written to disk. This replacement 909 * for write when passed the basic allocation size of a file system block, 910 * uses lseek whenever it detects the input data is all 0 within that 911 * file block. In more detail, the strategy is as follows: 912 * While the input is all zero keep doing an lseek. Keep track of when we 913 * pass over file block boundaries. Only write when we hit a non zero 914 * input. once we have written a file block, we continue to write it to 915 * the end (we stop looking at the input). When we reach the start of the 916 * next file block, start checking for zero blocks again. Working on file 917 * block boundaries significantly reduces the overhead when copying files 918 * that are NOT very sparse. This overhead (when compared to a write) is 919 * almost below the measurement resolution on many systems. Without it, 920 * files with holes cannot be safely copied. It does has a side effect as 921 * it can put holes into files that did not have them before, but that is 922 * not a problem since the file contents are unchanged (in fact it saves 923 * file space). (Except on paging files for diskless clients. But since we 924 * cannot determine one of those file from here, we ignore them). If this 925 * ever ends up on a system where CTG files are supported and the holes 926 * are not desired, just do a conditional test in those routines that 927 * call file_write() and have it call write() instead. BEFORE CLOSING THE 928 * FILE, make sure to call file_flush() when the last write finishes with 929 * an empty block. A lot of file systems will not create an lseek hole at 930 * the end. In this case we drop a single 0 at the end to force the 931 * trailing 0's in the file. 932 * ---Parameters--- 933 * rem: how many bytes left in this file system block 934 * isempt: have we written to the file block yet (is it empty) 935 * sz: basic file block allocation size 936 * cnt: number of bytes on this write 937 * str: buffer to write 938 * Return: 939 * number of bytes written, -1 on write (or lseek) error. 940 */ 941 942int 943file_write(int fd, char *str, int cnt, int *rem, int *isempt, int sz, 944 char *name) 945{ 946 char *pt; 947 char *end; 948 int wcnt; 949 char *st = str; 950 char **strp; 951 size_t *lenp; 952 953 /* 954 * while we have data to process 955 */ 956 while (cnt) { 957 if (!*rem) { 958 /* 959 * We are now at the start of file system block again 960 * (or what we think one is...). start looking for 961 * empty blocks again 962 */ 963 *isempt = 1; 964 *rem = sz; 965 } 966 967 /* 968 * only examine up to the end of the current file block or 969 * remaining characters to write, whatever is smaller 970 */ 971 wcnt = MIN(cnt, *rem); 972 cnt -= wcnt; 973 *rem -= wcnt; 974 if (*isempt) { 975 /* 976 * have not written to this block yet, so we keep 977 * looking for zero's 978 */ 979 pt = st; 980 end = st + wcnt; 981 982 /* 983 * look for a zero filled buffer 984 */ 985 while ((pt < end) && (*pt == '\0')) 986 ++pt; 987 988 if (pt == end) { 989 /* 990 * skip, buf is empty so far 991 */ 992 if (fd > -1 && 993 lseek(fd, (off_t)wcnt, SEEK_CUR) < 0) { 994 syswarn(1, errno, "File seek on %s", 995 name); 996 return -1; 997 } 998 st = pt; 999 continue; 1000 } 1001 /* 1002 * drat, the buf is not zero filled 1003 */ 1004 *isempt = 0; 1005 } 1006 1007 /* 1008 * have non-zero data in this file system block, have to write 1009 */ 1010 switch (fd) { 1011 case -PAX_GLF: 1012 strp = &gnu_name_string; 1013 lenp = &gnu_name_length; 1014 break; 1015 case -PAX_GLL: 1016 strp = &gnu_link_string; 1017 lenp = &gnu_link_length; 1018 break; 1019 default: 1020 strp = NULL; 1021 lenp = NULL; 1022 break; 1023 } 1024 if (strp) { 1025 char *nstr = *strp ? realloc(*strp, *lenp + wcnt + 1) : 1026 malloc(wcnt + 1); 1027 if (nstr == NULL) { 1028 tty_warn(1, "Out of memory"); 1029 return -1; 1030 } 1031 (void)strlcpy(&nstr[*lenp], st, wcnt + 1); 1032 *strp = nstr; 1033 *lenp += wcnt; 1034 } else if (xwrite(fd, st, wcnt) != wcnt) { 1035 syswarn(1, errno, "Failed write to file %s", name); 1036 return -1; 1037 } 1038 st += wcnt; 1039 } 1040 return st - str; 1041} 1042 1043/* 1044 * file_flush() 1045 * when the last file block in a file is zero, many file systems will not 1046 * let us create a hole at the end. To get the last block with zeros, we 1047 * write the last BYTE with a zero (back up one byte and write a zero). 1048 */ 1049 1050void 1051file_flush(int fd, char *fname, int isempt) 1052{ 1053 static char blnk[] = "\0"; 1054 1055 /* 1056 * silly test, but make sure we are only called when the last block is 1057 * filled with all zeros. 1058 */ 1059 if (!isempt) 1060 return; 1061 1062 /* 1063 * move back one byte and write a zero 1064 */ 1065 if (lseek(fd, (off_t)-1, SEEK_CUR) < 0) { 1066 syswarn(1, errno, "Failed seek on file %s", fname); 1067 return; 1068 } 1069 1070 if (write_with_restart(fd, blnk, 1) < 0) 1071 syswarn(1, errno, "Failed write to file %s", fname); 1072 return; 1073} 1074 1075/* 1076 * rdfile_close() 1077 * close a file we have been reading (to copy or archive). If we have to 1078 * reset access time (tflag) do so (the times are stored in arcn). 1079 */ 1080 1081void 1082rdfile_close(ARCHD *arcn, int *fd) 1083{ 1084 /* 1085 * make sure the file is open 1086 */ 1087 if (*fd < 0) 1088 return; 1089 1090 (void)close(*fd); 1091 *fd = -1; 1092 if (!tflag) 1093 return; 1094 1095 /* 1096 * user wants last access time reset 1097 */ 1098 set_ftime(arcn->org_name, arcn->sb.st_mtime, arcn->sb.st_atime, 1, 0); 1099 return; 1100} 1101 1102/* 1103 * set_crc() 1104 * read a file to calculate its crc. This is a real drag. Archive formats 1105 * that have this, end up reading the file twice (we have to write the 1106 * header WITH the crc before writing the file contents. Oh well... 1107 * Return: 1108 * 0 if was able to calculate the crc, -1 otherwise 1109 */ 1110 1111int 1112set_crc(ARCHD *arcn, int fd) 1113{ 1114 int i; 1115 int res; 1116 off_t cpcnt = 0L; 1117 u_long size; 1118 unsigned long crc = 0L; 1119 char tbuf[FILEBLK]; 1120 struct stat sb; 1121 1122 if (fd < 0) { 1123 /* 1124 * hmm, no fd, should never happen. well no crc then. 1125 */ 1126 arcn->crc = 0L; 1127 return 0; 1128 } 1129 1130 if ((size = (u_long)arcn->sb.st_blksize) > (u_long)sizeof(tbuf)) 1131 size = (u_long)sizeof(tbuf); 1132 1133 /* 1134 * read all the bytes we think that there are in the file. If the user 1135 * is trying to archive an active file, forget this file. 1136 */ 1137 for(;;) { 1138 if ((res = read(fd, tbuf, size)) <= 0) 1139 break; 1140 cpcnt += res; 1141 for (i = 0; i < res; ++i) 1142 crc += (tbuf[i] & 0xff); 1143 } 1144 1145 /* 1146 * safety check. we want to avoid archiving files that are active as 1147 * they can create inconsistent archive copies. 1148 */ 1149 if (cpcnt != arcn->sb.st_size) 1150 tty_warn(1, "File changed size %s", arcn->org_name); 1151 else if (fstat(fd, &sb) < 0) 1152 syswarn(1, errno, "Failed stat on %s", arcn->org_name); 1153 else if (arcn->sb.st_mtime != sb.st_mtime) 1154 tty_warn(1, "File %s was modified during read", arcn->org_name); 1155 else if (lseek(fd, (off_t)0L, SEEK_SET) < 0) 1156 syswarn(1, errno, "File rewind failed on: %s", arcn->org_name); 1157 else { 1158 arcn->crc = crc; 1159 return 0; 1160 } 1161 return -1; 1162} 1163