file_subs.c revision 1.43
1/* $NetBSD: file_subs.c,v 1.43 2004/04/25 16:20:24 christos 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 1.43 2004/04/25 16:20:24 christos 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 77#define FILEBITS (S_ISVTX | S_IRWXU | S_IRWXG | S_IRWXO) 78#define SETBITS (S_ISUID | S_ISGID) 79#define ABITS (FILEBITS | SETBITS) 80 81/* 82 * file_creat() 83 * Create and open a file. 84 * Return: 85 * file descriptor or -1 for failure 86 */ 87 88int 89file_creat(ARCHD *arcn) 90{ 91 int fd = -1; 92 int oerrno; 93 94 /* 95 * Some horribly busted tar implementations, have directory nodes 96 * that end in a /, but they mark as files. Compensate for that 97 * by not creating a directory node at this point, but a file node, 98 * and not creating the temp file. 99 */ 100 if (arcn->nlen != 0 && arcn->name[arcn->nlen - 1] == '/') { 101 if (!warn_broken) { 102 tty_warn(1, "Archive was created with a broken tar;" 103 " file `%s' is a directory, but marked as plain.", 104 arcn->name); 105 warn_broken = 1; 106 } 107 return -1; 108 } 109 /* 110 * Create a temporary file name so that the file doesn't have partial 111 * contents while restoring. 112 */ 113 arcn->tmp_name = malloc(arcn->nlen + 8); 114 if (arcn->tmp_name == NULL) { 115 syswarn(1, errno, "Cannot malloc %d bytes", arcn->nlen + 8); 116 return(-1); 117 } 118 if (xtmp_name) 119 abort(); 120 xtmp_name = arcn->tmp_name; 121 122 for (;;) { 123 /* 124 * try to create the temporary file we use to restore the 125 * contents info. if this fails, keep checking all the nodes 126 * in the path until chk_path() finds that it cannot fix 127 * anything further. if that happens we just give up. 128 */ 129 (void)snprintf(arcn->tmp_name, arcn->nlen + 8, "%s.XXXXXX", 130 arcn->name); 131 fd = mkstemp(arcn->tmp_name); 132 if (fd >= 0) 133 break; 134 oerrno = errno; 135 if (nodirs || chk_path(arcn->name,arcn->sb.st_uid,arcn->sb.st_gid) < 0) { 136 (void)fflush(listf); 137 syswarn(1, oerrno, "Cannot create %s", arcn->tmp_name); 138 xtmp_name = NULL; 139 free(arcn->tmp_name); 140 arcn->tmp_name = NULL; 141 return(-1); 142 } 143 } 144 return(fd); 145} 146 147/* 148 * file_close() 149 * Close file descriptor to a file just created by pax. Sets modes, 150 * ownership and times as required. 151 * Return: 152 * 0 for success, -1 for failure 153 */ 154 155void 156file_close(ARCHD *arcn, int fd) 157{ 158 int res = 0; 159 160 if (fd < 0) 161 return; 162 if (close(fd) < 0) 163 syswarn(0, errno, "Cannot close file descriptor on %s", 164 arcn->tmp_name); 165 166 /* 167 * set owner/groups first as this may strip off mode bits we want 168 * then set file permission modes. Then set file access and 169 * modification times. 170 */ 171 if (pids) 172 res = set_ids(arcn->tmp_name, arcn->sb.st_uid, arcn->sb.st_gid); 173 174 /* 175 * IMPORTANT SECURITY NOTE: 176 * if not preserving mode or we cannot set uid/gid, then PROHIBIT 177 * set uid/gid bits but restore the file modes (since mkstemp doesn't). 178 */ 179 if (!pmode || res) 180 arcn->sb.st_mode &= ~(SETBITS); 181 if (pmode) 182 set_pmode(arcn->tmp_name, arcn->sb.st_mode); 183 else 184 set_pmode(arcn->tmp_name, arcn->sb.st_mode & FILEBITS); 185 if (patime || pmtime) 186 set_ftime(arcn->tmp_name, arcn->sb.st_mtime, arcn->sb.st_atime, 0); 187#if HAVE_STRUCT_STAT_ST_FLAGS 188 if (pfflags && arcn->type != PAX_SLK) 189 set_chflags(arcn->tmp_name, arcn->sb.st_flags); 190#endif 191 192 /* 193 * Finally, now the temp file is fully instantiated rename it to 194 * the desired file name. 195 */ 196 if (rename(arcn->tmp_name, arcn->name) < 0) { 197 syswarn(0, errno, "Cannot rename %s to %s", 198 arcn->tmp_name, arcn->name); 199 (void)unlink(arcn->tmp_name); 200 } 201 202 free(arcn->tmp_name); 203 arcn->tmp_name = NULL; 204 xtmp_name = NULL; 205} 206 207/* 208 * lnk_creat() 209 * Create a hard link to arcn->ln_name from arcn->name. arcn->ln_name 210 * must exist; 211 * Return: 212 * 0 if ok, -1 otherwise 213 */ 214 215int 216lnk_creat(ARCHD *arcn) 217{ 218 struct stat sb; 219 220 /* 221 * we may be running as root, so we have to be sure that link target 222 * is not a directory, so we lstat and check 223 */ 224 if (lstat(arcn->ln_name, &sb) < 0) { 225 syswarn(1, errno, "Cannot link to %s from %s", arcn->ln_name, 226 arcn->name); 227 return(-1); 228 } 229 230 if (S_ISDIR(sb.st_mode)) { 231 tty_warn(1, "A hard link to the directory %s is not allowed", 232 arcn->ln_name); 233 return(-1); 234 } 235 236 return(mk_link(arcn->ln_name, &sb, arcn->name, 0)); 237} 238 239/* 240 * cross_lnk() 241 * Create a hard link to arcn->org_name from arcn->name. Only used in copy 242 * with the -l flag. No warning or error if this does not succeed (we will 243 * then just create the file) 244 * Return: 245 * 1 if copy() should try to create this file node 246 * 0 if cross_lnk() ok, -1 for fatal flaw (like linking to self). 247 */ 248 249int 250cross_lnk(ARCHD *arcn) 251{ 252 /* 253 * try to make a link to original file (-l flag in copy mode). make 254 * sure we do not try to link to directories in case we are running as 255 * root (and it might succeed). 256 */ 257 if (arcn->type == PAX_DIR) 258 return(1); 259 return(mk_link(arcn->org_name, &(arcn->sb), arcn->name, 1)); 260} 261 262/* 263 * chk_same() 264 * In copy mode if we are not trying to make hard links between the src 265 * and destinations, make sure we are not going to overwrite ourselves by 266 * accident. This slows things down a little, but we have to protect all 267 * those people who make typing errors. 268 * Return: 269 * 1 the target does not exist, go ahead and copy 270 * 0 skip it file exists (-k) or may be the same as source file 271 */ 272 273int 274chk_same(ARCHD *arcn) 275{ 276 struct stat sb; 277 278 /* 279 * if file does not exist, return. if file exists and -k, skip it 280 * quietly 281 */ 282 if (lstat(arcn->name, &sb) < 0) 283 return(1); 284 if (kflag) 285 return(0); 286 287 /* 288 * better make sure the user does not have src == dest by mistake 289 */ 290 if ((arcn->sb.st_dev == sb.st_dev) && (arcn->sb.st_ino == sb.st_ino)) { 291 tty_warn(1, "Unable to copy %s, file would overwrite itself", 292 arcn->name); 293 return(0); 294 } 295 return(1); 296} 297 298/* 299 * mk_link() 300 * try to make a hard link between two files. if ign set, we do not 301 * complain. 302 * Return: 303 * 0 if successful (or we are done with this file but no error, such as 304 * finding the from file exists and the user has set -k). 305 * 1 when ign was set to indicates we could not make the link but we 306 * should try to copy/extract the file as that might work (and is an 307 * allowed option). -1 an error occurred. 308 */ 309 310static int 311mk_link(char *to, struct stat *to_sb, char *from, int ign) 312{ 313 struct stat sb; 314 int oerrno; 315 316 /* 317 * if from file exists, it has to be unlinked to make the link. If the 318 * file exists and -k is set, skip it quietly 319 */ 320 if (lstat(from, &sb) == 0) { 321 if (kflag) 322 return(0); 323 324 /* 325 * make sure it is not the same file, protect the user 326 */ 327 if ((to_sb->st_dev==sb.st_dev)&&(to_sb->st_ino == sb.st_ino)) { 328 tty_warn(1, "Cannot link file %s to itself", to); 329 return(-1); 330 } 331 332 /* 333 * try to get rid of the file, based on the type 334 */ 335 if (S_ISDIR(sb.st_mode)) { 336 if (rmdir(from) < 0) { 337 syswarn(1, errno, "Cannot remove %s", from); 338 return(-1); 339 } 340 } else if (unlink(from) < 0) { 341 if (!ign) { 342 syswarn(1, errno, "Cannot remove %s", from); 343 return(-1); 344 } 345 return(1); 346 } 347 } 348 349 /* 350 * from file is gone (or did not exist), try to make the hard link. 351 * if it fails, check the path and try it again (if chk_path() says to 352 * try again) 353 */ 354 for (;;) { 355 if (link(to, from) == 0) 356 break; 357 oerrno = errno; 358 if (chk_path(from, to_sb->st_uid, to_sb->st_gid) == 0) 359 continue; 360 if (!ign) { 361 syswarn(1, oerrno, "Cannot link to %s from %s", to, 362 from); 363 return(-1); 364 } 365 return(1); 366 } 367 368 /* 369 * all right the link was made 370 */ 371 return(0); 372} 373 374/* 375 * node_creat() 376 * create an entry in the file system (other than a file or hard link). 377 * If successful, sets uid/gid modes and times as required. 378 * Return: 379 * 0 if ok, -1 otherwise 380 */ 381 382int 383node_creat(ARCHD *arcn) 384{ 385 int res; 386 int ign = 0; 387 int oerrno; 388 int pass = 0; 389 mode_t file_mode; 390 struct stat sb; 391 char target[MAXPATHLEN]; 392 char *nm = arcn->name; 393 int len; 394 395 /* 396 * create node based on type, if that fails try to unlink the node and 397 * try again. finally check the path and try again. As noted in the 398 * file and link creation routines, this method seems to exhibit the 399 * best performance in general use workloads. 400 */ 401 file_mode = arcn->sb.st_mode & FILEBITS; 402 403 for (;;) { 404 switch(arcn->type) { 405 case PAX_DIR: 406 /* 407 * If -h (or -L) was given in tar-mode, follow the 408 * potential symlink chain before trying to create the 409 * directory. 410 */ 411 if (strcmp(NM_TAR, argv0) == 0 && Lflag) { 412 while (lstat(nm, &sb) == 0 && 413 S_ISLNK(sb.st_mode)) { 414 len = readlink(nm, target, 415 sizeof target - 1); 416 if (len == -1) { 417 syswarn(0, errno, 418 "cannot follow symlink %s in chain for %s", 419 nm, arcn->name); 420 res = -1; 421 goto badlink; 422 } 423 target[len] = '\0'; 424 nm = target; 425 } 426 } 427 res = mkdir(nm, file_mode); 428 429badlink: 430 if (ign) 431 res = 0; 432 break; 433 case PAX_CHR: 434 file_mode |= S_IFCHR; 435 res = mknod(nm, file_mode, arcn->sb.st_rdev); 436 break; 437 case PAX_BLK: 438 file_mode |= S_IFBLK; 439 res = mknod(nm, file_mode, arcn->sb.st_rdev); 440 break; 441 case PAX_FIF: 442 res = mkfifo(nm, file_mode); 443 break; 444 case PAX_SCK: 445 /* 446 * Skip sockets, operation has no meaning under BSD 447 */ 448 tty_warn(0, 449 "%s skipped. Sockets cannot be copied or extracted", 450 nm); 451 return(-1); 452 case PAX_SLK: 453 res = symlink(arcn->ln_name, nm); 454 break; 455 case PAX_CTG: 456 case PAX_HLK: 457 case PAX_HRG: 458 case PAX_REG: 459 default: 460 /* 461 * we should never get here 462 */ 463 tty_warn(0, "%s has an unknown file type, skipping", 464 nm); 465 return(-1); 466 } 467 468 /* 469 * if we were able to create the node break out of the loop, 470 * otherwise try to unlink the node and try again. if that 471 * fails check the full path and try a final time. 472 */ 473 if (res == 0) 474 break; 475 476 /* 477 * we failed to make the node 478 */ 479 oerrno = errno; 480 if ((ign = unlnk_exist(nm, arcn->type)) < 0) 481 return(-1); 482 483 if (++pass <= 1) 484 continue; 485 486 if (nodirs || chk_path(nm,arcn->sb.st_uid,arcn->sb.st_gid) < 0) { 487 syswarn(1, oerrno, "Cannot create %s", nm); 488 return(-1); 489 } 490 } 491 492 /* 493 * we were able to create the node. set uid/gid, modes and times 494 */ 495 if (pids) 496 res = set_ids(nm, arcn->sb.st_uid, arcn->sb.st_gid); 497 else 498 res = 0; 499 500 /* 501 * IMPORTANT SECURITY NOTE: 502 * if not preserving mode or we cannot set uid/gid, then PROHIBIT any 503 * set uid/gid bits 504 */ 505 if (!pmode || res) 506 arcn->sb.st_mode &= ~(SETBITS); 507 if (pmode) 508 set_pmode(arcn->name, arcn->sb.st_mode); 509 510 if (arcn->type == PAX_DIR && strcmp(NM_CPIO, argv0) != 0) { 511 /* 512 * Dirs must be processed again at end of extract to set times 513 * and modes to agree with those stored in the archive. However 514 * to allow extract to continue, we may have to also set owner 515 * rights. This allows nodes in the archive that are children 516 * of this directory to be extracted without failure. Both time 517 * and modes will be fixed after the entire archive is read and 518 * before pax exits. 519 */ 520 if (access(nm, R_OK | W_OK | X_OK) < 0) { 521 if (lstat(nm, &sb) < 0) { 522 syswarn(0, errno,"Cannot access %s (stat)", 523 arcn->name); 524 set_pmode(nm,file_mode | S_IRWXU); 525 } else { 526 /* 527 * We have to add rights to the dir, so we make 528 * sure to restore the mode. The mode must be 529 * restored AS CREATED and not as stored if 530 * pmode is not set. 531 */ 532 set_pmode(nm, 533 ((sb.st_mode & FILEBITS) | S_IRWXU)); 534 if (!pmode) 535 arcn->sb.st_mode = sb.st_mode; 536 } 537 538 /* 539 * we have to force the mode to what was set here, 540 * since we changed it from the default as created. 541 */ 542 add_dir(nm, arcn->nlen, &(arcn->sb), 1); 543 } else if (pmode || patime || pmtime) 544 add_dir(nm, arcn->nlen, &(arcn->sb), 0); 545 } 546 547#if HAVE_LUTIMES 548 if (patime || pmtime) 549#else 550 if ((patime || pmtime) && arcn->type != PAX_SLK) 551#endif 552 set_ftime(arcn->name, arcn->sb.st_mtime, arcn->sb.st_atime, 0); 553 554#if HAVE_STRUCT_STAT_ST_FLAGS 555 if (pfflags && arcn->type != PAX_SLK) 556 set_chflags(arcn->name, arcn->sb.st_flags); 557#endif 558 return(0); 559} 560 561/* 562 * unlnk_exist() 563 * Remove node from file system with the specified name. We pass the type 564 * of the node that is going to replace it. When we try to create a 565 * directory and find that it already exists, we allow processing to 566 * continue as proper modes etc will always be set for it later on. 567 * Return: 568 * 0 is ok to proceed, no file with the specified name exists 569 * -1 we were unable to remove the node, or we should not remove it (-k) 570 * 1 we found a directory and we were going to create a directory. 571 */ 572 573int 574unlnk_exist(char *name, int type) 575{ 576 struct stat sb; 577 578 /* 579 * the file does not exist, or -k we are done 580 */ 581 if (lstat(name, &sb) < 0) 582 return(0); 583 if (kflag) 584 return(-1); 585 586 if (S_ISDIR(sb.st_mode)) { 587 /* 588 * try to remove a directory, if it fails and we were going to 589 * create a directory anyway, tell the caller (return a 1) 590 */ 591 if (rmdir(name) < 0) { 592 if (type == PAX_DIR) 593 return(1); 594 syswarn(1, errno, "Cannot remove directory %s", name); 595 return(-1); 596 } 597 return(0); 598 } 599 600 /* 601 * try to get rid of all non-directory type nodes 602 */ 603 if (unlink(name) < 0) { 604 (void)fflush(listf); 605 syswarn(1, errno, "Cannot unlink %s", name); 606 return(-1); 607 } 608 return(0); 609} 610 611/* 612 * chk_path() 613 * We were trying to create some kind of node in the file system and it 614 * failed. chk_path() makes sure the path up to the node exists and is 615 * writable. When we have to create a directory that is missing along the 616 * path somewhere, the directory we create will be set to the same 617 * uid/gid as the file has (when uid and gid are being preserved). 618 * NOTE: this routine is a real performance loss. It is only used as a 619 * last resort when trying to create entries in the file system. 620 * Return: 621 * -1 when it could find nothing it is allowed to fix. 622 * 0 otherwise 623 */ 624 625int 626chk_path( char *name, uid_t st_uid, gid_t st_gid) 627{ 628 char *spt = name; 629 struct stat sb; 630 int retval = -1; 631 632 /* 633 * watch out for paths with nodes stored directly in / (e.g. /bozo) 634 */ 635 if (*spt == '/') 636 ++spt; 637 638 for(;;) { 639 /* 640 * work forward from the first / and check each part of 641 * the path 642 */ 643 spt = strchr(spt, '/'); 644 if (spt == NULL) 645 break; 646 *spt = '\0'; 647 648 /* 649 * if it exists we assume it is a directory, it is not within 650 * the spec (at least it seems to read that way) to alter the 651 * file system for nodes NOT EXPLICITLY stored on the archive. 652 * If that assumption is changed, you would test the node here 653 * and figure out how to get rid of it (probably like some 654 * recursive unlink()) or fix up the directory permissions if 655 * required (do an access()). 656 */ 657 if (lstat(name, &sb) == 0) { 658 *(spt++) = '/'; 659 continue; 660 } 661 662 /* 663 * the path fails at this point, see if we can create the 664 * needed directory and continue on 665 */ 666 if (mkdir(name, S_IRWXU | S_IRWXG | S_IRWXO) < 0) { 667 *spt = '/'; 668 retval = -1; 669 break; 670 } 671 672 /* 673 * we were able to create the directory. We will tell the 674 * caller that we found something to fix, and it is ok to try 675 * and create the node again. 676 */ 677 retval = 0; 678 if (pids) 679 (void)set_ids(name, st_uid, st_gid); 680 681 /* 682 * make sure the user doesn't have some strange umask that 683 * causes this newly created directory to be unusable. We fix 684 * the modes and restore them back to the creation default at 685 * the end of pax 686 */ 687 if ((access(name, R_OK | W_OK | X_OK) < 0) && 688 (lstat(name, &sb) == 0)) { 689 set_pmode(name, ((sb.st_mode & FILEBITS) | S_IRWXU)); 690 add_dir(name, spt - name, &sb, 1); 691 } 692 *(spt++) = '/'; 693 continue; 694 } 695 return(retval); 696} 697 698/* 699 * set_ftime() 700 * Set the access time and modification time for a named file. If frc 701 * is non-zero we force these times to be set even if the user did not 702 * request access and/or modification time preservation (this is also 703 * used by -t to reset access times). 704 * When ign is zero, only those times the user has asked for are set, the 705 * other ones are left alone. We do not assume the un-documented feature 706 * of many utimes() implementations that consider a 0 time value as a do 707 * not set request. 708 */ 709 710void 711set_ftime(char *fnm, time_t mtime, time_t atime, int frc) 712{ 713 struct timeval tv[2]; 714 struct stat sb; 715 716 tv[0].tv_sec = (long)atime; 717 tv[0].tv_usec = 0; 718 tv[1].tv_sec = (long)mtime; 719 tv[1].tv_usec = 0; 720 if (!frc && (!patime || !pmtime)) { 721 /* 722 * if we are not forcing, only set those times the user wants 723 * set. We get the current values of the times if we need them. 724 */ 725 if (lstat(fnm, &sb) == 0) { 726#ifdef BSD4_4 727 if (!patime) 728 TIMESPEC_TO_TIMEVAL(&tv[0], &sb.st_atimespec); 729 if (!pmtime) 730 TIMESPEC_TO_TIMEVAL(&tv[1], &sb.st_mtimespec); 731#else 732 if (!patime) 733 tv[0].tv_sec = sb.st_atime; 734 if (!pmtime) 735 tv[1].tv_sec = sb.st_mtime; 736#endif 737 } else 738 syswarn(0, errno, "Cannot obtain file stats %s", fnm); 739 } 740 741 /* 742 * set the times 743 */ 744#if HAVE_LUTIMES 745 if (lutimes(fnm, tv)) 746#else 747 if (utimes(fnm, tv)) 748#endif 749 syswarn(1, errno, "Access/modification time set failed on: %s", 750 fnm); 751 return; 752} 753 754/* 755 * set_ids() 756 * set the uid and gid of a file system node 757 * Return: 758 * 0 when set, -1 on failure 759 */ 760 761int 762set_ids(char *fnm, uid_t uid, gid_t gid) 763{ 764 if (geteuid() == 0) 765 if (lchown(fnm, uid, gid)) { 766 (void)fflush(listf); 767 syswarn(1, errno, "Cannot set file uid/gid of %s", 768 fnm); 769 return(-1); 770 } 771 return(0); 772} 773 774/* 775 * set_pmode() 776 * Set file access mode 777 */ 778 779void 780set_pmode(char *fnm, mode_t mode) 781{ 782 mode &= ABITS; 783 if (lchmod(fnm, mode)) { 784 (void)fflush(listf); 785 syswarn(1, errno, "Cannot set permissions on %s", fnm); 786 } 787 return; 788} 789 790/* 791 * set_chflags() 792 * Set 4.4BSD file flags 793 */ 794void 795set_chflags(char *fnm, u_int32_t flags) 796{ 797 798#if 0 799 if (chflags(fnm, flags) < 0 && errno != EOPNOTSUPP) 800 syswarn(1, errno, "Cannot set file flags on %s", fnm); 801#endif 802 return; 803} 804 805/* 806 * file_write() 807 * Write/copy a file (during copy or archive extract). This routine knows 808 * how to copy files with lseek holes in it. (Which are read as file 809 * blocks containing all 0's but do not have any file blocks associated 810 * with the data). Typical examples of these are files created by dbm 811 * variants (.pag files). While the file size of these files are huge, the 812 * actual storage is quite small (the files are sparse). The problem is 813 * the holes read as all zeros so are probably stored on the archive that 814 * way (there is no way to determine if the file block is really a hole, 815 * we only know that a file block of all zero's can be a hole). 816 * At this writing, no major archive format knows how to archive files 817 * with holes. However, on extraction (or during copy, -rw) we have to 818 * deal with these files. Without detecting the holes, the files can 819 * consume a lot of file space if just written to disk. This replacement 820 * for write when passed the basic allocation size of a file system block, 821 * uses lseek whenever it detects the input data is all 0 within that 822 * file block. In more detail, the strategy is as follows: 823 * While the input is all zero keep doing an lseek. Keep track of when we 824 * pass over file block boundaries. Only write when we hit a non zero 825 * input. once we have written a file block, we continue to write it to 826 * the end (we stop looking at the input). When we reach the start of the 827 * next file block, start checking for zero blocks again. Working on file 828 * block boundaries significantly reduces the overhead when copying files 829 * that are NOT very sparse. This overhead (when compared to a write) is 830 * almost below the measurement resolution on many systems. Without it, 831 * files with holes cannot be safely copied. It does has a side effect as 832 * it can put holes into files that did not have them before, but that is 833 * not a problem since the file contents are unchanged (in fact it saves 834 * file space). (Except on paging files for diskless clients. But since we 835 * cannot determine one of those file from here, we ignore them). If this 836 * ever ends up on a system where CTG files are supported and the holes 837 * are not desired, just do a conditional test in those routines that 838 * call file_write() and have it call write() instead. BEFORE CLOSING THE 839 * FILE, make sure to call file_flush() when the last write finishes with 840 * an empty block. A lot of file systems will not create an lseek hole at 841 * the end. In this case we drop a single 0 at the end to force the 842 * trailing 0's in the file. 843 * ---Parameters--- 844 * rem: how many bytes left in this file system block 845 * isempt: have we written to the file block yet (is it empty) 846 * sz: basic file block allocation size 847 * cnt: number of bytes on this write 848 * str: buffer to write 849 * Return: 850 * number of bytes written, -1 on write (or lseek) error. 851 */ 852 853int 854file_write(int fd, char *str, int cnt, int *rem, int *isempt, int sz, 855 char *name) 856{ 857 char *pt; 858 char *end; 859 int wcnt; 860 char *st = str; 861 char **strp; 862 863 /* 864 * while we have data to process 865 */ 866 while (cnt) { 867 if (!*rem) { 868 /* 869 * We are now at the start of file system block again 870 * (or what we think one is...). start looking for 871 * empty blocks again 872 */ 873 *isempt = 1; 874 *rem = sz; 875 } 876 877 /* 878 * only examine up to the end of the current file block or 879 * remaining characters to write, whatever is smaller 880 */ 881 wcnt = MIN(cnt, *rem); 882 cnt -= wcnt; 883 *rem -= wcnt; 884 if (*isempt) { 885 /* 886 * have not written to this block yet, so we keep 887 * looking for zero's 888 */ 889 pt = st; 890 end = st + wcnt; 891 892 /* 893 * look for a zero filled buffer 894 */ 895 while ((pt < end) && (*pt == '\0')) 896 ++pt; 897 898 if (pt == end) { 899 /* 900 * skip, buf is empty so far 901 */ 902 if (fd > -1 && 903 lseek(fd, (off_t)wcnt, SEEK_CUR) < 0) { 904 syswarn(1, errno, "File seek on %s", 905 name); 906 return(-1); 907 } 908 st = pt; 909 continue; 910 } 911 /* 912 * drat, the buf is not zero filled 913 */ 914 *isempt = 0; 915 } 916 917 /* 918 * have non-zero data in this file system block, have to write 919 */ 920 switch (fd) { 921 case -1: 922 strp = &gnu_name_string; 923 break; 924 case -2: 925 strp = &gnu_link_string; 926 break; 927 default: 928 strp = NULL; 929 break; 930 } 931 if (strp) { 932 if (*strp) 933 err(1, "WARNING! Major Internal Error! GNU hack Failing!"); 934 *strp = malloc(wcnt + 1); 935 if (*strp == NULL) { 936 tty_warn(1, "Out of memory"); 937 return(-1); 938 } 939 strlcpy(*strp, st, wcnt); 940 break; 941 } else if (xwrite(fd, st, wcnt) != wcnt) { 942 syswarn(1, errno, "Failed write to file %s", name); 943 return(-1); 944 } 945 st += wcnt; 946 } 947 return(st - str); 948} 949 950/* 951 * file_flush() 952 * when the last file block in a file is zero, many file systems will not 953 * let us create a hole at the end. To get the last block with zeros, we 954 * write the last BYTE with a zero (back up one byte and write a zero). 955 */ 956 957void 958file_flush(int fd, char *fname, int isempt) 959{ 960 static char blnk[] = "\0"; 961 962 /* 963 * silly test, but make sure we are only called when the last block is 964 * filled with all zeros. 965 */ 966 if (!isempt) 967 return; 968 969 /* 970 * move back one byte and write a zero 971 */ 972 if (lseek(fd, (off_t)-1, SEEK_CUR) < 0) { 973 syswarn(1, errno, "Failed seek on file %s", fname); 974 return; 975 } 976 977 if (write_with_restart(fd, blnk, 1) < 0) 978 syswarn(1, errno, "Failed write to file %s", fname); 979 return; 980} 981 982/* 983 * rdfile_close() 984 * close a file we have been reading (to copy or archive). If we have to 985 * reset access time (tflag) do so (the times are stored in arcn). 986 */ 987 988void 989rdfile_close(ARCHD *arcn, int *fd) 990{ 991 /* 992 * make sure the file is open 993 */ 994 if (*fd < 0) 995 return; 996 997 (void)close(*fd); 998 *fd = -1; 999 if (!tflag) 1000 return; 1001 1002 /* 1003 * user wants last access time reset 1004 */ 1005 set_ftime(arcn->org_name, arcn->sb.st_mtime, arcn->sb.st_atime, 1); 1006 return; 1007} 1008 1009/* 1010 * set_crc() 1011 * read a file to calculate its crc. This is a real drag. Archive formats 1012 * that have this, end up reading the file twice (we have to write the 1013 * header WITH the crc before writing the file contents. Oh well... 1014 * Return: 1015 * 0 if was able to calculate the crc, -1 otherwise 1016 */ 1017 1018int 1019set_crc(ARCHD *arcn, int fd) 1020{ 1021 int i; 1022 int res; 1023 off_t cpcnt = 0L; 1024 u_long size; 1025 unsigned long crc = 0L; 1026 char tbuf[FILEBLK]; 1027 struct stat sb; 1028 1029 if (fd < 0) { 1030 /* 1031 * hmm, no fd, should never happen. well no crc then. 1032 */ 1033 arcn->crc = 0L; 1034 return(0); 1035 } 1036 1037 if ((size = (u_long)arcn->sb.st_blksize) > (u_long)sizeof(tbuf)) 1038 size = (u_long)sizeof(tbuf); 1039 1040 /* 1041 * read all the bytes we think that there are in the file. If the user 1042 * is trying to archive an active file, forget this file. 1043 */ 1044 for(;;) { 1045 if ((res = read(fd, tbuf, size)) <= 0) 1046 break; 1047 cpcnt += res; 1048 for (i = 0; i < res; ++i) 1049 crc += (tbuf[i] & 0xff); 1050 } 1051 1052 /* 1053 * safety check. we want to avoid archiving files that are active as 1054 * they can create inconsistant archive copies. 1055 */ 1056 if (cpcnt != arcn->sb.st_size) 1057 tty_warn(1, "File changed size %s", arcn->org_name); 1058 else if (fstat(fd, &sb) < 0) 1059 syswarn(1, errno, "Failed stat on %s", arcn->org_name); 1060 else if (arcn->sb.st_mtime != sb.st_mtime) 1061 tty_warn(1, "File %s was modified during read", arcn->org_name); 1062 else if (lseek(fd, (off_t)0L, SEEK_SET) < 0) 1063 syswarn(1, errno, "File rewind failed on: %s", arcn->org_name); 1064 else { 1065 arcn->crc = crc; 1066 return(0); 1067 } 1068 return(-1); 1069} 1070