file_subs.c revision 1.32
1/* $NetBSD: file_subs.c,v 1.32 2003/02/10 07:49:57 grant Exp $ */ 2 3/*- 4 * Copyright (c) 1992 Keith Muller. 5 * Copyright (c) 1992, 1993 6 * The Regents of the University of California. All rights reserved. 7 * 8 * This code is derived from software contributed to Berkeley by 9 * Keith Muller of the University of California, San Diego. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. All advertising materials mentioning features or use of this software 20 * must display the following acknowledgement: 21 * This product includes software developed by the University of 22 * California, Berkeley and its contributors. 23 * 4. Neither the name of the University nor the names of its contributors 24 * may be used to endorse or promote products derived from this software 25 * without specific prior written permission. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 30 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 37 * SUCH DAMAGE. 38 */ 39 40#include <sys/cdefs.h> 41#if defined(__RCSID) && !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 1.32 2003/02/10 07:49:57 grant 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 65static int 66mk_link(char *,struct stat *,char *, int); 67 68/* 69 * routines that deal with file operations such as: creating, removing; 70 * and setting access modes, uid/gid and times of files 71 */ 72 73#define FILEBITS (S_ISVTX | S_IRWXU | S_IRWXG | S_IRWXO) 74#define SETBITS (S_ISUID | S_ISGID) 75#define ABITS (FILEBITS | SETBITS) 76 77/* 78 * file_creat() 79 * Create and open a file. 80 * Return: 81 * file descriptor or -1 for failure 82 */ 83 84int 85file_creat(ARCHD *arcn) 86{ 87 int fd = -1; 88 mode_t file_mode; 89 int oerrno; 90 91 /* 92 * assume file doesn't exist, so just try to create it, most times this 93 * works. We have to take special handling when the file does exist. To 94 * detect this, we use O_EXCL. For example when trying to create a 95 * file and a character device or fifo exists with the same name, we 96 * can accidently open the device by mistake (or block waiting to open) 97 * If we find that the open has failed, then spend the effort to 98 * figure out why. This strategy was found to have better average 99 * performance in common use than checking the file (and the path) 100 * first with lstat. 101 */ 102 file_mode = arcn->sb.st_mode & FILEBITS; 103 if ((fd = open(arcn->name, O_WRONLY | O_CREAT | O_TRUNC | O_EXCL, 104 file_mode)) >= 0) 105 return(fd); 106 107 /* 108 * the file seems to exist. First we try to get rid of it (found to be 109 * the second most common failure when traced). If this fails, only 110 * then we go to the expense to check and create the path to the file 111 */ 112 if (unlnk_exist(arcn->name, arcn->type) != 0) 113 return(-1); 114 115 for (;;) { 116 /* 117 * try to open it again, if this fails, check all the nodes in 118 * the path and give it a final try. if chk_path() finds that 119 * it cannot fix anything, we will skip the last attempt 120 */ 121 if ((fd = open(arcn->name, O_WRONLY | O_CREAT | O_TRUNC, 122 file_mode)) >= 0) 123 break; 124 oerrno = errno; 125 if (nodirs || chk_path(arcn->name,arcn->sb.st_uid,arcn->sb.st_gid) < 0) { 126 (void)fflush(listf); 127 syswarn(1, oerrno, "Cannot create %s", arcn->name); 128 return(-1); 129 } 130 } 131 return(fd); 132} 133 134/* 135 * file_close() 136 * Close file descriptor to a file just created by pax. Sets modes, 137 * ownership and times as required. 138 * Return: 139 * 0 for success, -1 for failure 140 */ 141 142void 143file_close(ARCHD *arcn, int fd) 144{ 145 int res = 0; 146 147 if (fd < 0) 148 return; 149 if (close(fd) < 0) 150 syswarn(0, errno, "Cannot close file descriptor on %s", 151 arcn->name); 152 153 /* 154 * set owner/groups first as this may strip off mode bits we want 155 * then set file permission modes. Then set file access and 156 * modification times. 157 */ 158 if (pids) 159 res = set_ids(arcn->name, arcn->sb.st_uid, arcn->sb.st_gid); 160 161 /* 162 * IMPORTANT SECURITY NOTE: 163 * if not preserving mode or we cannot set uid/gid, then PROHIBIT 164 * set uid/gid bits 165 */ 166 if (!pmode || res) 167 arcn->sb.st_mode &= ~(SETBITS); 168 if (pmode) 169 set_pmode(arcn->name, arcn->sb.st_mode); 170 if (patime || pmtime) 171 set_ftime(arcn->name, arcn->sb.st_mtime, arcn->sb.st_atime, 0); 172#if HAVE_STRUCT_STAT_ST_FLAGS 173 if (pfflags && arcn->type != PAX_SLK) 174 set_chflags(arcn->name, arcn->sb.st_flags); 175#endif 176} 177 178/* 179 * lnk_creat() 180 * Create a hard link to arcn->ln_name from arcn->name. arcn->ln_name 181 * must exist; 182 * Return: 183 * 0 if ok, -1 otherwise 184 */ 185 186int 187lnk_creat(ARCHD *arcn) 188{ 189 struct stat sb; 190 191 /* 192 * we may be running as root, so we have to be sure that link target 193 * is not a directory, so we lstat and check 194 */ 195 if (lstat(arcn->ln_name, &sb) < 0) { 196 syswarn(1, errno, "Cannot link to %s from %s", arcn->ln_name, 197 arcn->name); 198 return(-1); 199 } 200 201 if (S_ISDIR(sb.st_mode)) { 202 tty_warn(1, "A hard link to the directory %s is not allowed", 203 arcn->ln_name); 204 return(-1); 205 } 206 207 return(mk_link(arcn->ln_name, &sb, arcn->name, 0)); 208} 209 210/* 211 * cross_lnk() 212 * Create a hard link to arcn->org_name from arcn->name. Only used in copy 213 * with the -l flag. No warning or error if this does not succeed (we will 214 * then just create the file) 215 * Return: 216 * 1 if copy() should try to create this file node 217 * 0 if cross_lnk() ok, -1 for fatal flaw (like linking to self). 218 */ 219 220int 221cross_lnk(ARCHD *arcn) 222{ 223 /* 224 * try to make a link to original file (-l flag in copy mode). make 225 * sure we do not try to link to directories in case we are running as 226 * root (and it might succeed). 227 */ 228 if (arcn->type == PAX_DIR) 229 return(1); 230 return(mk_link(arcn->org_name, &(arcn->sb), arcn->name, 1)); 231} 232 233/* 234 * chk_same() 235 * In copy mode if we are not trying to make hard links between the src 236 * and destinations, make sure we are not going to overwrite ourselves by 237 * accident. This slows things down a little, but we have to protect all 238 * those people who make typing errors. 239 * Return: 240 * 1 the target does not exist, go ahead and copy 241 * 0 skip it file exists (-k) or may be the same as source file 242 */ 243 244int 245chk_same(ARCHD *arcn) 246{ 247 struct stat sb; 248 249 /* 250 * if file does not exist, return. if file exists and -k, skip it 251 * quietly 252 */ 253 if (lstat(arcn->name, &sb) < 0) 254 return(1); 255 if (kflag) 256 return(0); 257 258 /* 259 * better make sure the user does not have src == dest by mistake 260 */ 261 if ((arcn->sb.st_dev == sb.st_dev) && (arcn->sb.st_ino == sb.st_ino)) { 262 tty_warn(1, "Unable to copy %s, file would overwrite itself", 263 arcn->name); 264 return(0); 265 } 266 return(1); 267} 268 269/* 270 * mk_link() 271 * try to make a hard link between two files. if ign set, we do not 272 * complain. 273 * Return: 274 * 0 if successful (or we are done with this file but no error, such as 275 * finding the from file exists and the user has set -k). 276 * 1 when ign was set to indicates we could not make the link but we 277 * should try to copy/extract the file as that might work (and is an 278 * allowed option). -1 an error occurred. 279 */ 280 281static int 282mk_link(char *to, struct stat *to_sb, char *from, int ign) 283{ 284 struct stat sb; 285 int oerrno; 286 287 /* 288 * if from file exists, it has to be unlinked to make the link. If the 289 * file exists and -k is set, skip it quietly 290 */ 291 if (lstat(from, &sb) == 0) { 292 if (kflag) 293 return(0); 294 295 /* 296 * make sure it is not the same file, protect the user 297 */ 298 if ((to_sb->st_dev==sb.st_dev)&&(to_sb->st_ino == sb.st_ino)) { 299 tty_warn(1, "Cannot link file %s to itself", to); 300 return(-1); 301 } 302 303 /* 304 * try to get rid of the file, based on the type 305 */ 306 if (S_ISDIR(sb.st_mode)) { 307 if (rmdir(from) < 0) { 308 syswarn(1, errno, "Cannot remove %s", from); 309 return(-1); 310 } 311 } else if (unlink(from) < 0) { 312 if (!ign) { 313 syswarn(1, errno, "Cannot remove %s", from); 314 return(-1); 315 } 316 return(1); 317 } 318 } 319 320 /* 321 * from file is gone (or did not exist), try to make the hard link. 322 * if it fails, check the path and try it again (if chk_path() says to 323 * try again) 324 */ 325 for (;;) { 326 if (link(to, from) == 0) 327 break; 328 oerrno = errno; 329 if (chk_path(from, to_sb->st_uid, to_sb->st_gid) == 0) 330 continue; 331 if (!ign) { 332 syswarn(1, oerrno, "Cannot link to %s from %s", to, 333 from); 334 return(-1); 335 } 336 return(1); 337 } 338 339 /* 340 * all right the link was made 341 */ 342 return(0); 343} 344 345/* 346 * node_creat() 347 * create an entry in the file system (other than a file or hard link). 348 * If successful, sets uid/gid modes and times as required. 349 * Return: 350 * 0 if ok, -1 otherwise 351 */ 352 353int 354node_creat(ARCHD *arcn) 355{ 356 int res; 357 int ign = 0; 358 int oerrno; 359 int pass = 0; 360 mode_t file_mode; 361 struct stat sb; 362 char target[MAXPATHLEN]; 363 char *nm = arcn->name; 364 int len; 365 366 /* 367 * create node based on type, if that fails try to unlink the node and 368 * try again. finally check the path and try again. As noted in the 369 * file and link creation routines, this method seems to exhibit the 370 * best performance in general use workloads. 371 */ 372 file_mode = arcn->sb.st_mode & FILEBITS; 373 374 for (;;) { 375 switch(arcn->type) { 376 case PAX_DIR: 377 /* 378 * If -h (or -L) was given in tar-mode, follow the 379 * potential symlink chain before trying to create the 380 * directory. 381 */ 382 if (strcmp(NM_TAR, argv0) == 0 && Lflag) { 383 while (lstat(nm, &sb) == 0 && 384 S_ISLNK(sb.st_mode)) { 385 len = readlink(nm, target, 386 sizeof target - 1); 387 if (len == -1) { 388 syswarn(0, errno, 389 "cannot follow symlink %s in chain for %s", 390 nm, arcn->name); 391 res = -1; 392 goto badlink; 393 } 394 target[len] = '\0'; 395 nm = target; 396 } 397 } 398 res = mkdir(nm, file_mode); 399 400badlink: 401 if (ign) 402 res = 0; 403 break; 404 case PAX_CHR: 405 file_mode |= S_IFCHR; 406 res = mknod(nm, file_mode, arcn->sb.st_rdev); 407 break; 408 case PAX_BLK: 409 file_mode |= S_IFBLK; 410 res = mknod(nm, file_mode, arcn->sb.st_rdev); 411 break; 412 case PAX_FIF: 413 res = mkfifo(nm, file_mode); 414 break; 415 case PAX_SCK: 416 /* 417 * Skip sockets, operation has no meaning under BSD 418 */ 419 tty_warn(0, 420 "%s skipped. Sockets cannot be copied or extracted", 421 nm); 422 return(-1); 423 case PAX_SLK: 424 res = symlink(arcn->ln_name, nm); 425 break; 426 case PAX_CTG: 427 case PAX_HLK: 428 case PAX_HRG: 429 case PAX_REG: 430 default: 431 /* 432 * we should never get here 433 */ 434 tty_warn(0, "%s has an unknown file type, skipping", 435 nm); 436 return(-1); 437 } 438 439 /* 440 * if we were able to create the node break out of the loop, 441 * otherwise try to unlink the node and try again. if that 442 * fails check the full path and try a final time. 443 */ 444 if (res == 0) 445 break; 446 447 /* 448 * we failed to make the node 449 */ 450 oerrno = errno; 451 if ((ign = unlnk_exist(nm, arcn->type)) < 0) 452 return(-1); 453 454 if (++pass <= 1) 455 continue; 456 457 if (nodirs || chk_path(nm,arcn->sb.st_uid,arcn->sb.st_gid) < 0) { 458 syswarn(1, oerrno, "Cannot create %s", nm); 459 return(-1); 460 } 461 } 462 463 /* 464 * we were able to create the node. set uid/gid, modes and times 465 */ 466#if HAVE_LCHOWN 467 if (pids) 468#else 469 if (pids && arcn->type != PAX_SLK) 470#endif 471 res = set_ids(nm, arcn->sb.st_uid, arcn->sb.st_gid); 472 else 473 res = 0; 474 475 /* 476 * IMPORTANT SECURITY NOTE: 477 * if not preserving mode or we cannot set uid/gid, then PROHIBIT any 478 * set uid/gid bits 479 */ 480 if (!pmode || res) 481 arcn->sb.st_mode &= ~(SETBITS); 482#if HAVE_LCHMOD 483 if (pmode) 484#else 485 if (pmode && arcn->type != PAX_SLK) 486#endif 487 set_pmode(arcn->name, arcn->sb.st_mode); 488 489 if (arcn->type == PAX_DIR && strcmp(NM_CPIO, argv0) != 0) { 490 /* 491 * Dirs must be processed again at end of extract to set times 492 * and modes to agree with those stored in the archive. However 493 * to allow extract to continue, we may have to also set owner 494 * rights. This allows nodes in the archive that are children 495 * of this directory to be extracted without failure. Both time 496 * and modes will be fixed after the entire archive is read and 497 * before pax exits. 498 */ 499 if (access(nm, R_OK | W_OK | X_OK) < 0) { 500 if (lstat(nm, &sb) < 0) { 501 syswarn(0, errno,"Cannot access %s (stat)", 502 arcn->name); 503 set_pmode(nm,file_mode | S_IRWXU); 504 } else { 505 /* 506 * We have to add rights to the dir, so we make 507 * sure to restore the mode. The mode must be 508 * restored AS CREATED and not as stored if 509 * pmode is not set. 510 */ 511 set_pmode(nm, 512 ((sb.st_mode & FILEBITS) | S_IRWXU)); 513 if (!pmode) 514 arcn->sb.st_mode = sb.st_mode; 515 } 516 517 /* 518 * we have to force the mode to what was set here, 519 * since we changed it from the default as created. 520 */ 521 add_dir(nm, arcn->nlen, &(arcn->sb), 1); 522 } else if (pmode || patime || pmtime) 523 add_dir(nm, arcn->nlen, &(arcn->sb), 0); 524 } 525 526#if HAVE_LUTIMES 527 if (patime || pmtime) 528#else 529 if ((patime || pmtime) && arcn->type != PAX_SLK) 530#endif 531 set_ftime(arcn->name, arcn->sb.st_mtime, arcn->sb.st_atime, 0); 532 533#if HAVE_STRUCT_STAT_ST_FLAGS 534 if (pfflags && arcn->type != PAX_SLK) 535 set_chflags(arcn->name, arcn->sb.st_flags); 536#endif 537 return(0); 538} 539 540/* 541 * unlnk_exist() 542 * Remove node from file system with the specified name. We pass the type 543 * of the node that is going to replace it. When we try to create a 544 * directory and find that it already exists, we allow processing to 545 * continue as proper modes etc will always be set for it later on. 546 * Return: 547 * 0 is ok to proceed, no file with the specified name exists 548 * -1 we were unable to remove the node, or we should not remove it (-k) 549 * 1 we found a directory and we were going to create a directory. 550 */ 551 552int 553unlnk_exist(char *name, int type) 554{ 555 struct stat sb; 556 557 /* 558 * the file does not exist, or -k we are done 559 */ 560 if (lstat(name, &sb) < 0) 561 return(0); 562 if (kflag) 563 return(-1); 564 565 if (S_ISDIR(sb.st_mode)) { 566 /* 567 * try to remove a directory, if it fails and we were going to 568 * create a directory anyway, tell the caller (return a 1) 569 */ 570 if (rmdir(name) < 0) { 571 if (type == PAX_DIR) 572 return(1); 573 syswarn(1, errno, "Cannot remove directory %s", name); 574 return(-1); 575 } 576 return(0); 577 } 578 579 /* 580 * try to get rid of all non-directory type nodes 581 */ 582 if (unlink(name) < 0) { 583 (void)fflush(listf); 584 syswarn(1, errno, "Cannot unlink %s", name); 585 return(-1); 586 } 587 return(0); 588} 589 590/* 591 * chk_path() 592 * We were trying to create some kind of node in the file system and it 593 * failed. chk_path() makes sure the path up to the node exists and is 594 * writable. When we have to create a directory that is missing along the 595 * path somewhere, the directory we create will be set to the same 596 * uid/gid as the file has (when uid and gid are being preserved). 597 * NOTE: this routine is a real performance loss. It is only used as a 598 * last resort when trying to create entries in the file system. 599 * Return: 600 * -1 when it could find nothing it is allowed to fix. 601 * 0 otherwise 602 */ 603 604int 605chk_path( char *name, uid_t st_uid, gid_t st_gid) 606{ 607 char *spt = name; 608 struct stat sb; 609 int retval = -1; 610 611 /* 612 * watch out for paths with nodes stored directly in / (e.g. /bozo) 613 */ 614 if (*spt == '/') 615 ++spt; 616 617 for(;;) { 618 /* 619 * work forward from the first / and check each part of 620 * the path 621 */ 622 spt = strchr(spt, '/'); 623 if (spt == NULL) 624 break; 625 *spt = '\0'; 626 627 /* 628 * if it exists we assume it is a directory, it is not within 629 * the spec (at least it seems to read that way) to alter the 630 * file system for nodes NOT EXPLICITLY stored on the archive. 631 * If that assumption is changed, you would test the node here 632 * and figure out how to get rid of it (probably like some 633 * recursive unlink()) or fix up the directory permissions if 634 * required (do an access()). 635 */ 636 if (lstat(name, &sb) == 0) { 637 *(spt++) = '/'; 638 continue; 639 } 640 641 /* 642 * the path fails at this point, see if we can create the 643 * needed directory and continue on 644 */ 645 if (mkdir(name, S_IRWXU | S_IRWXG | S_IRWXO) < 0) { 646 *spt = '/'; 647 retval = -1; 648 break; 649 } 650 651 /* 652 * we were able to create the directory. We will tell the 653 * caller that we found something to fix, and it is ok to try 654 * and create the node again. 655 */ 656 retval = 0; 657 if (pids) 658 (void)set_ids(name, st_uid, st_gid); 659 660 /* 661 * make sure the user doesn't have some strange umask that 662 * causes this newly created directory to be unusable. We fix 663 * the modes and restore them back to the creation default at 664 * the end of pax 665 */ 666 if ((access(name, R_OK | W_OK | X_OK) < 0) && 667 (lstat(name, &sb) == 0)) { 668 set_pmode(name, ((sb.st_mode & FILEBITS) | S_IRWXU)); 669 add_dir(name, spt - name, &sb, 1); 670 } 671 *(spt++) = '/'; 672 continue; 673 } 674 return(retval); 675} 676 677/* 678 * set_ftime() 679 * Set the access time and modification time for a named file. If frc 680 * is non-zero we force these times to be set even if the user did not 681 * request access and/or modification time preservation (this is also 682 * used by -t to reset access times). 683 * When ign is zero, only those times the user has asked for are set, the 684 * other ones are left alone. We do not assume the un-documented feature 685 * of many utimes() implementations that consider a 0 time value as a do 686 * not set request. 687 */ 688 689void 690set_ftime(char *fnm, time_t mtime, time_t atime, int frc) 691{ 692 struct timeval tv[2]; 693 struct stat sb; 694 695 tv[0].tv_sec = (long)atime; 696 tv[0].tv_usec = 0; 697 tv[1].tv_sec = (long)mtime; 698 tv[1].tv_usec = 0; 699 if (!frc && (!patime || !pmtime)) { 700 /* 701 * if we are not forcing, only set those times the user wants 702 * set. We get the current values of the times if we need them. 703 */ 704 if (lstat(fnm, &sb) == 0) { 705#ifdef BSD4_4 706 if (!patime) 707 TIMESPEC_TO_TIMEVAL(&tv[0], &sb.st_atimespec); 708 if (!pmtime) 709 TIMESPEC_TO_TIMEVAL(&tv[1], &sb.st_mtimespec); 710#else 711 if (!patime) 712 tv[0].tv_sec = sb.st_atime; 713 if (!pmtime) 714 tv[1].tv_sec = sb.st_mtime; 715#endif 716 } else 717 syswarn(0, errno, "Cannot obtain file stats %s", fnm); 718 } 719 720 /* 721 * set the times 722 */ 723#if HAVE_LUTIMES 724 if (lutimes(fnm, tv)) 725#else 726 if (utimes(fnm, tv)) 727#endif 728 syswarn(1, errno, "Access/modification time set failed on: %s", 729 fnm); 730 return; 731} 732 733/* 734 * set_ids() 735 * set the uid and gid of a file system node 736 * Return: 737 * 0 when set, -1 on failure 738 */ 739 740int 741set_ids(char *fnm, uid_t uid, gid_t gid) 742{ 743 if (geteuid() == 0) 744#if HAVE_LCHOWN 745 if (lchown(fnm, uid, gid)) 746#else 747 if (chown(fnm, uid, gid)) 748#endif 749 { 750 (void)fflush(listf); 751 syswarn(1, errno, "Cannot set file uid/gid of %s", 752 fnm); 753 return(-1); 754 } 755 return(0); 756} 757 758/* 759 * set_pmode() 760 * Set file access mode 761 */ 762 763void 764set_pmode(char *fnm, mode_t mode) 765{ 766 mode &= ABITS; 767#if HAVE_LCHMOD 768 if (lchmod(fnm, mode)) 769#else 770 if (chmod(fnm, mode)) 771#endif 772 { 773 (void)fflush(listf); 774 syswarn(1, errno, "Cannot set permissions on %s", fnm); 775 } 776 return; 777} 778 779/* 780 * set_chflags() 781 * Set 4.4BSD file flags 782 */ 783void 784set_chflags(char *fnm, u_int32_t flags) 785{ 786 787#if 0 788 if (chflags(fnm, flags) < 0 && errno != EOPNOTSUPP) 789 syswarn(1, errno, "Cannot set file flags on %s", fnm); 790#endif 791 return; 792} 793 794/* 795 * file_write() 796 * Write/copy a file (during copy or archive extract). This routine knows 797 * how to copy files with lseek holes in it. (Which are read as file 798 * blocks containing all 0's but do not have any file blocks associated 799 * with the data). Typical examples of these are files created by dbm 800 * variants (.pag files). While the file size of these files are huge, the 801 * actual storage is quite small (the files are sparse). The problem is 802 * the holes read as all zeros so are probably stored on the archive that 803 * way (there is no way to determine if the file block is really a hole, 804 * we only know that a file block of all zero's can be a hole). 805 * At this writing, no major archive format knows how to archive files 806 * with holes. However, on extraction (or during copy, -rw) we have to 807 * deal with these files. Without detecting the holes, the files can 808 * consume a lot of file space if just written to disk. This replacement 809 * for write when passed the basic allocation size of a file system block, 810 * uses lseek whenever it detects the input data is all 0 within that 811 * file block. In more detail, the strategy is as follows: 812 * While the input is all zero keep doing an lseek. Keep track of when we 813 * pass over file block boundaries. Only write when we hit a non zero 814 * input. once we have written a file block, we continue to write it to 815 * the end (we stop looking at the input). When we reach the start of the 816 * next file block, start checking for zero blocks again. Working on file 817 * block boundaries significantly reduces the overhead when copying files 818 * that are NOT very sparse. This overhead (when compared to a write) is 819 * almost below the measurement resolution on many systems. Without it, 820 * files with holes cannot be safely copied. It does has a side effect as 821 * it can put holes into files that did not have them before, but that is 822 * not a problem since the file contents are unchanged (in fact it saves 823 * file space). (Except on paging files for diskless clients. But since we 824 * cannot determine one of those file from here, we ignore them). If this 825 * ever ends up on a system where CTG files are supported and the holes 826 * are not desired, just do a conditional test in those routines that 827 * call file_write() and have it call write() instead. BEFORE CLOSING THE 828 * FILE, make sure to call file_flush() when the last write finishes with 829 * an empty block. A lot of file systems will not create an lseek hole at 830 * the end. In this case we drop a single 0 at the end to force the 831 * trailing 0's in the file. 832 * ---Parameters--- 833 * rem: how many bytes left in this file system block 834 * isempt: have we written to the file block yet (is it empty) 835 * sz: basic file block allocation size 836 * cnt: number of bytes on this write 837 * str: buffer to write 838 * Return: 839 * number of bytes written, -1 on write (or lseek) error. 840 */ 841 842int 843file_write(int fd, char *str, int cnt, int *rem, int *isempt, int sz, 844 char *name) 845{ 846 char *pt; 847 char *end; 848 int wcnt; 849 char *st = str; 850 char **strp; 851 852 /* 853 * while we have data to process 854 */ 855 while (cnt) { 856 if (!*rem) { 857 /* 858 * We are now at the start of file system block again 859 * (or what we think one is...). start looking for 860 * empty blocks again 861 */ 862 *isempt = 1; 863 *rem = sz; 864 } 865 866 /* 867 * only examine up to the end of the current file block or 868 * remaining characters to write, whatever is smaller 869 */ 870 wcnt = MIN(cnt, *rem); 871 cnt -= wcnt; 872 *rem -= wcnt; 873 if (*isempt) { 874 /* 875 * have not written to this block yet, so we keep 876 * looking for zero's 877 */ 878 pt = st; 879 end = st + wcnt; 880 881 /* 882 * look for a zero filled buffer 883 */ 884 while ((pt < end) && (*pt == '\0')) 885 ++pt; 886 887 if (pt == end) { 888 /* 889 * skip, buf is empty so far 890 */ 891 if (fd > -1 && 892 lseek(fd, (off_t)wcnt, SEEK_CUR) < 0) { 893 syswarn(1, errno, "File seek on %s", 894 name); 895 return(-1); 896 } 897 st = pt; 898 continue; 899 } 900 /* 901 * drat, the buf is not zero filled 902 */ 903 *isempt = 0; 904 } 905 906 /* 907 * have non-zero data in this file system block, have to write 908 */ 909 switch (fd) { 910 case -1: 911 strp = &gnu_name_string; 912 break; 913 case -2: 914 strp = &gnu_link_string; 915 break; 916 default: 917 strp = NULL; 918 break; 919 } 920 if (strp) { 921 if (*strp) 922 err(1, "WARNING! Major Internal Error! GNU hack Failing!"); 923 *strp = malloc(wcnt + 1); 924 if (*strp == NULL) { 925 tty_warn(1, "Out of memory"); 926 return(-1); 927 } 928 strlcpy(*strp, st, wcnt); 929 break; 930 } else if (xwrite(fd, st, wcnt) != wcnt) { 931 syswarn(1, errno, "Failed write to file %s", name); 932 return(-1); 933 } 934 st += wcnt; 935 } 936 return(st - str); 937} 938 939/* 940 * file_flush() 941 * when the last file block in a file is zero, many file systems will not 942 * let us create a hole at the end. To get the last block with zeros, we 943 * write the last BYTE with a zero (back up one byte and write a zero). 944 */ 945 946void 947file_flush(int fd, char *fname, int isempt) 948{ 949 static char blnk[] = "\0"; 950 951 /* 952 * silly test, but make sure we are only called when the last block is 953 * filled with all zeros. 954 */ 955 if (!isempt) 956 return; 957 958 /* 959 * move back one byte and write a zero 960 */ 961 if (lseek(fd, (off_t)-1, SEEK_CUR) < 0) { 962 syswarn(1, errno, "Failed seek on file %s", fname); 963 return; 964 } 965 966 if (write_with_restart(fd, blnk, 1) < 0) 967 syswarn(1, errno, "Failed write to file %s", fname); 968 return; 969} 970 971/* 972 * rdfile_close() 973 * close a file we have been reading (to copy or archive). If we have to 974 * reset access time (tflag) do so (the times are stored in arcn). 975 */ 976 977void 978rdfile_close(ARCHD *arcn, int *fd) 979{ 980 /* 981 * make sure the file is open 982 */ 983 if (*fd < 0) 984 return; 985 986 (void)close(*fd); 987 *fd = -1; 988 if (!tflag) 989 return; 990 991 /* 992 * user wants last access time reset 993 */ 994 set_ftime(arcn->org_name, arcn->sb.st_mtime, arcn->sb.st_atime, 1); 995 return; 996} 997 998/* 999 * set_crc() 1000 * read a file to calculate its crc. This is a real drag. Archive formats 1001 * that have this, end up reading the file twice (we have to write the 1002 * header WITH the crc before writing the file contents. Oh well... 1003 * Return: 1004 * 0 if was able to calculate the crc, -1 otherwise 1005 */ 1006 1007int 1008set_crc(ARCHD *arcn, int fd) 1009{ 1010 int i; 1011 int res; 1012 off_t cpcnt = 0L; 1013 u_long size; 1014 unsigned long crc = 0L; 1015 char tbuf[FILEBLK]; 1016 struct stat sb; 1017 1018 if (fd < 0) { 1019 /* 1020 * hmm, no fd, should never happen. well no crc then. 1021 */ 1022 arcn->crc = 0L; 1023 return(0); 1024 } 1025 1026 if ((size = (u_long)arcn->sb.st_blksize) > (u_long)sizeof(tbuf)) 1027 size = (u_long)sizeof(tbuf); 1028 1029 /* 1030 * read all the bytes we think that there are in the file. If the user 1031 * is trying to archive an active file, forget this file. 1032 */ 1033 for(;;) { 1034 if ((res = read(fd, tbuf, size)) <= 0) 1035 break; 1036 cpcnt += res; 1037 for (i = 0; i < res; ++i) 1038 crc += (tbuf[i] & 0xff); 1039 } 1040 1041 /* 1042 * safety check. we want to avoid archiving files that are active as 1043 * they can create inconsistant archive copies. 1044 */ 1045 if (cpcnt != arcn->sb.st_size) 1046 tty_warn(1, "File changed size %s", arcn->org_name); 1047 else if (fstat(fd, &sb) < 0) 1048 syswarn(1, errno, "Failed stat on %s", arcn->org_name); 1049 else if (arcn->sb.st_mtime != sb.st_mtime) 1050 tty_warn(1, "File %s was modified during read", arcn->org_name); 1051 else if (lseek(fd, (off_t)0L, SEEK_SET) < 0) 1052 syswarn(1, errno, "File rewind failed on: %s", arcn->org_name); 1053 else { 1054 arcn->crc = crc; 1055 return(0); 1056 } 1057 return(-1); 1058} 1059