More minor IPI work.
[dragonfly/vkernel-mp.git] / bin / pax / file_subs.c
blob9a54b425a26caec5accf1aba527de1bdedaf0d54
1 /*-
2 * Copyright (c) 1992 Keith Muller.
3 * Copyright (c) 1992, 1993
4 * The Regents of the University of California. All rights reserved.
6 * This code is derived from software contributed to Berkeley by
7 * Keith Muller of the University of California, San Diego.
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 3. All advertising materials mentioning features or use of this software
18 * must display the following acknowledgement:
19 * This product includes software developed by the University of
20 * California, Berkeley and its contributors.
21 * 4. Neither the name of the University nor the names of its contributors
22 * may be used to endorse or promote products derived from this software
23 * without specific prior written permission.
25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 * SUCH DAMAGE.
37 * @(#)file_subs.c 8.1 (Berkeley) 5/31/93
38 * $FreeBSD: src/bin/pax/file_subs.c,v 1.12.2.1 2001/08/01 05:03:11 obrien Exp $
39 * $DragonFly: src/bin/pax/file_subs.c,v 1.8 2006/09/27 23:58:08 pavalos Exp $
42 #include <sys/types.h>
43 #include <sys/time.h>
44 #include <sys/stat.h>
45 #include <unistd.h>
46 #include <fcntl.h>
47 #include <string.h>
48 #include <stdio.h>
49 #include <errno.h>
50 #include <sys/uio.h>
51 #include <stdlib.h>
52 #include "pax.h"
53 #include "options.h"
54 #include "extern.h"
56 static int
57 mk_link (char *,struct stat *,char *, int);
60 * routines that deal with file operations such as: creating, removing;
61 * and setting access modes, uid/gid and times of files
64 #define FILEBITS (S_ISVTX | S_IRWXU | S_IRWXG | S_IRWXO)
65 #define SETBITS (S_ISUID | S_ISGID)
66 #define ABITS (FILEBITS | SETBITS)
69 * file_creat()
70 * Create and open a file.
71 * Return:
72 * file descriptor or -1 for failure
75 int
76 file_creat(ARCHD *arcn)
78 int fd = -1;
79 mode_t file_mode;
80 int oerrno;
83 * Assume file doesn't exist, so just try to create it, most times this
84 * works. We have to take special handling when the file does exist. To
85 * detect this, we use O_EXCL. For example when trying to create a
86 * file and a character device or fifo exists with the same name, we
87 * can accidently open the device by mistake (or block waiting to open).
88 * If we find that the open has failed, then spend the effort to
89 * figure out why. This strategy was found to have better average
90 * performance in common use than checking the file (and the path)
91 * first with lstat.
93 file_mode = arcn->sb.st_mode & FILEBITS;
94 if ((fd = open(arcn->name, O_WRONLY | O_CREAT | O_TRUNC | O_EXCL,
95 file_mode)) >= 0)
96 return(fd);
99 * the file seems to exist. First we try to get rid of it (found to be
100 * the second most common failure when traced). If this fails, only
101 * then we go to the expense to check and create the path to the file
103 if (unlnk_exist(arcn->name, arcn->type) != 0)
104 return(-1);
106 for (;;) {
108 * try to open it again, if this fails, check all the nodes in
109 * the path and give it a final try. if chk_path() finds that
110 * it cannot fix anything, we will skip the last attempt
112 if ((fd = open(arcn->name, O_WRONLY | O_CREAT | O_TRUNC,
113 file_mode)) >= 0)
114 break;
115 oerrno = errno;
116 if (nodirs || chk_path(arcn->name,arcn->sb.st_uid,arcn->sb.st_gid) < 0) {
117 syswarn(1, oerrno, "Unable to create %s", arcn->name);
118 return(-1);
121 return(fd);
125 * file_close()
126 * Close file descriptor to a file just created by pax. Sets modes,
127 * ownership and times as required.
128 * Return:
129 * 0 for success, -1 for failure
132 void
133 file_close(ARCHD *arcn, int fd)
135 int res = 0;
137 if (fd < 0)
138 return;
139 if (close(fd) < 0)
140 syswarn(0, errno, "Unable to close file descriptor on %s",
141 arcn->name);
144 * set owner/groups first as this may strip off mode bits we want
145 * then set file permission modes. Then set file access and
146 * modification times.
148 if (pids)
149 res = set_ids(arcn->name, arcn->sb.st_uid, arcn->sb.st_gid);
152 * IMPORTANT SECURITY NOTE:
153 * if not preserving mode or we cannot set uid/gid, then PROHIBIT
154 * set uid/gid bits
156 if (!pmode || res)
157 arcn->sb.st_mode &= ~(SETBITS);
158 if (pmode)
159 set_pmode(arcn->name, arcn->sb.st_mode);
160 if (patime || pmtime)
161 set_ftime(arcn->name, arcn->sb.st_mtime, arcn->sb.st_atime, 0);
165 * lnk_creat()
166 * Create a hard link to arcn->ln_name from arcn->name. arcn->ln_name
167 * must exist;
168 * Return:
169 * 0 if ok, -1 otherwise
173 lnk_creat(ARCHD *arcn)
175 struct stat sb;
178 * we may be running as root, so we have to be sure that link target
179 * is not a directory, so we lstat and check
181 if (lstat(arcn->ln_name, &sb) < 0) {
182 syswarn(1,errno,"Unable to link to %s from %s", arcn->ln_name,
183 arcn->name);
184 return(-1);
187 if (S_ISDIR(sb.st_mode)) {
188 paxwarn(1, "A hard link to the directory %s is not allowed",
189 arcn->ln_name);
190 return(-1);
193 return(mk_link(arcn->ln_name, &sb, arcn->name, 0));
197 * cross_lnk()
198 * Create a hard link to arcn->org_name from arcn->name. Only used in copy
199 * with the -l flag. No warning or error if this does not succeed (we will
200 * then just create the file)
201 * Return:
202 * 1 if copy() should try to create this file node
203 * 0 if cross_lnk() ok, -1 for fatal flaw (like linking to self).
207 cross_lnk(ARCHD *arcn)
210 * try to make a link to original file (-l flag in copy mode). make sure
211 * we do not try to link to directories in case we are running as root
212 * (and it might succeed).
214 if (arcn->type == PAX_DIR)
215 return(1);
216 return(mk_link(arcn->org_name, &(arcn->sb), arcn->name, 1));
220 * chk_same()
221 * In copy mode if we are not trying to make hard links between the src
222 * and destinations, make sure we are not going to overwrite ourselves by
223 * accident. This slows things down a little, but we have to protect all
224 * those people who make typing errors.
225 * Return:
226 * 1 the target does not exist, go ahead and copy
227 * 0 skip it file exists (-k) or may be the same as source file
231 chk_same(ARCHD *arcn)
233 struct stat sb;
236 * if file does not exist, return. if file exists and -k, skip it
237 * quietly
239 if (lstat(arcn->name, &sb) < 0)
240 return(1);
241 if (kflag)
242 return(0);
245 * better make sure the user does not have src == dest by mistake
247 if ((arcn->sb.st_dev == sb.st_dev) && (arcn->sb.st_ino == sb.st_ino)) {
248 paxwarn(1, "Unable to copy %s, file would overwrite itself",
249 arcn->name);
250 return(0);
252 return(1);
256 * mk_link()
257 * try to make a hard link between two files. if ign set, we do not
258 * complain.
259 * Return:
260 * 0 if successful (or we are done with this file but no error, such as
261 * finding the from file exists and the user has set -k).
262 * 1 when ign was set to indicates we could not make the link but we
263 * should try to copy/extract the file as that might work (and is an
264 * allowed option). -1 an error occurred.
267 static int
268 mk_link(char *to, struct stat *to_sb, char *from,
269 int ign)
271 struct stat sb;
272 int oerrno;
275 * if from file exists, it has to be unlinked to make the link. If the
276 * file exists and -k is set, skip it quietly
278 if (lstat(from, &sb) == 0) {
279 if (kflag)
280 return(0);
283 * make sure it is not the same file, protect the user
285 if ((to_sb->st_dev==sb.st_dev)&&(to_sb->st_ino == sb.st_ino)) {
286 paxwarn(1, "Unable to link file %s to itself", to);
287 return(-1);
291 * try to get rid of the file, based on the type
293 if (S_ISDIR(sb.st_mode)) {
294 if (rmdir(from) < 0) {
295 syswarn(1, errno, "Unable to remove %s", from);
296 return(-1);
298 } else if (unlink(from) < 0) {
299 if (!ign) {
300 syswarn(1, errno, "Unable to remove %s", from);
301 return(-1);
303 return(1);
308 * from file is gone (or did not exist), try to make the hard link.
309 * if it fails, check the path and try it again (if chk_path() says to
310 * try again)
312 for (;;) {
313 if (link(to, from) == 0)
314 break;
315 oerrno = errno;
316 if (!nodirs && chk_path(from, to_sb->st_uid, to_sb->st_gid) == 0)
317 continue;
318 if (!ign) {
319 syswarn(1, oerrno, "Could not link to %s from %s", to,
320 from);
321 return(-1);
323 return(1);
327 * all right the link was made
329 return(0);
333 * node_creat()
334 * create an entry in the file system (other than a file or hard link).
335 * If successful, sets uid/gid modes and times as required.
336 * Return:
337 * 0 if ok, -1 otherwise
341 node_creat(ARCHD *arcn)
343 int res;
344 int ign = 0;
345 int oerrno;
346 int pass = 0;
347 mode_t file_mode;
348 struct stat sb;
351 * create node based on type, if that fails try to unlink the node and
352 * try again. finally check the path and try again. As noted in the
353 * file and link creation routines, this method seems to exhibit the
354 * best performance in general use workloads.
356 file_mode = arcn->sb.st_mode & FILEBITS;
358 for (;;) {
359 switch(arcn->type) {
360 case PAX_DIR:
361 res = mkdir(arcn->name, file_mode);
362 if (ign)
363 res = 0;
364 break;
365 case PAX_CHR:
366 file_mode |= S_IFCHR;
367 res = mknod(arcn->name, file_mode, arcn->sb.st_rdev);
368 break;
369 case PAX_BLK:
370 file_mode |= S_IFBLK;
371 res = mknod(arcn->name, file_mode, arcn->sb.st_rdev);
372 break;
373 case PAX_FIF:
374 res = mkfifo(arcn->name, file_mode);
375 break;
376 case PAX_SCK:
378 * Skip sockets, operation has no meaning under BSD
380 paxwarn(0,
381 "%s skipped. Sockets cannot be copied or extracted",
382 arcn->name);
383 return(-1);
384 case PAX_SLK:
385 res = symlink(arcn->ln_name, arcn->name);
386 break;
387 case PAX_CTG:
388 case PAX_HLK:
389 case PAX_HRG:
390 case PAX_REG:
391 default:
393 * we should never get here
395 paxwarn(0, "%s has an unknown file type, skipping",
396 arcn->name);
397 return(-1);
401 * if we were able to create the node break out of the loop,
402 * otherwise try to unlink the node and try again. if that
403 * fails check the full path and try a final time.
405 if (res == 0)
406 break;
409 * we failed to make the node
411 oerrno = errno;
412 if ((ign = unlnk_exist(arcn->name, arcn->type)) < 0)
413 return(-1);
415 if (++pass <= 1)
416 continue;
418 if (nodirs || chk_path(arcn->name,arcn->sb.st_uid,arcn->sb.st_gid) < 0) {
419 syswarn(1, oerrno, "Could not create: %s", arcn->name);
420 return(-1);
425 * we were able to create the node. set uid/gid, modes and times
427 if (pids)
428 res = ((arcn->type == PAX_SLK) ?
429 set_lids(arcn->name, arcn->sb.st_uid, arcn->sb.st_gid) :
430 set_ids(arcn->name, arcn->sb.st_uid, arcn->sb.st_gid));
431 else
432 res = 0;
435 * symlinks are done now.
437 if (arcn->type == PAX_SLK)
438 return(0);
441 * IMPORTANT SECURITY NOTE:
442 * if not preserving mode or we cannot set uid/gid, then PROHIBIT any
443 * set uid/gid bits
445 if (!pmode || res)
446 arcn->sb.st_mode &= ~(SETBITS);
447 if (pmode)
448 set_pmode(arcn->name, arcn->sb.st_mode);
450 if (arcn->type == PAX_DIR && strcmp(NM_CPIO, argv0) != 0) {
452 * Dirs must be processed again at end of extract to set times
453 * and modes to agree with those stored in the archive. However
454 * to allow extract to continue, we may have to also set owner
455 * rights. This allows nodes in the archive that are children
456 * of this directory to be extracted without failure. Both time
457 * and modes will be fixed after the entire archive is read and
458 * before pax exits.
460 if (access(arcn->name, R_OK | W_OK | X_OK) < 0) {
461 if (lstat(arcn->name, &sb) < 0) {
462 syswarn(0, errno,"Could not access %s (stat)",
463 arcn->name);
464 set_pmode(arcn->name,file_mode | S_IRWXU);
465 } else {
467 * We have to add rights to the dir, so we make
468 * sure to restore the mode. The mode must be
469 * restored AS CREATED and not as stored if
470 * pmode is not set.
472 set_pmode(arcn->name,
473 ((sb.st_mode & FILEBITS) | S_IRWXU));
474 if (!pmode)
475 arcn->sb.st_mode = sb.st_mode;
479 * we have to force the mode to what was set here,
480 * since we changed it from the default as created.
482 add_dir(arcn->name, arcn->nlen, &(arcn->sb), 1);
483 } else if (pmode || patime || pmtime)
484 add_dir(arcn->name, arcn->nlen, &(arcn->sb), 0);
487 if (patime || pmtime)
488 set_ftime(arcn->name, arcn->sb.st_mtime, arcn->sb.st_atime, 0);
489 return(0);
493 * unlnk_exist()
494 * Remove node from file system with the specified name. We pass the type
495 * of the node that is going to replace it. When we try to create a
496 * directory and find that it already exists, we allow processing to
497 * continue as proper modes etc will always be set for it later on.
498 * Return:
499 * 0 is ok to proceed, no file with the specified name exists
500 * -1 we were unable to remove the node, or we should not remove it (-k)
501 * 1 we found a directory and we were going to create a directory.
505 unlnk_exist(char *name, int type)
507 struct stat sb;
510 * the file does not exist, or -k we are done
512 if (lstat(name, &sb) < 0)
513 return(0);
514 if (kflag)
515 return(-1);
517 if (S_ISDIR(sb.st_mode)) {
519 * try to remove a directory, if it fails and we were going to
520 * create a directory anyway, tell the caller (return a 1)
522 if (rmdir(name) < 0) {
523 if (type == PAX_DIR)
524 return(1);
525 syswarn(1,errno,"Unable to remove directory %s", name);
526 return(-1);
528 return(0);
532 * try to get rid of all non-directory type nodes
534 if (unlink(name) < 0) {
535 syswarn(1, errno, "Could not unlink %s", name);
536 return(-1);
538 return(0);
542 * chk_path()
543 * We were trying to create some kind of node in the file system and it
544 * failed. chk_path() makes sure the path up to the node exists and is
545 * writeable. When we have to create a directory that is missing along the
546 * path somewhere, the directory we create will be set to the same
547 * uid/gid as the file has (when uid and gid are being preserved).
548 * NOTE: this routine is a real performance loss. It is only used as a
549 * last resort when trying to create entries in the file system.
550 * Return:
551 * -1 when it could find nothing it is allowed to fix.
552 * 0 otherwise
556 chk_path( char *name, uid_t st_uid, gid_t st_gid)
558 char *spt = name;
559 struct stat sb;
560 int retval = -1;
563 * watch out for paths with nodes stored directly in / (e.g. /bozo)
565 if (*spt == '/')
566 ++spt;
568 for(;;) {
570 * work forward from the first / and check each part of the path
572 spt = strchr(spt, '/');
573 if (spt == NULL)
574 break;
575 *spt = '\0';
578 * if it exists we assume it is a directory, it is not within
579 * the spec (at least it seems to read that way) to alter the
580 * file system for nodes NOT EXPLICITLY stored on the archive.
581 * If that assumption is changed, you would test the node here
582 * and figure out how to get rid of it (probably like some
583 * recursive unlink()) or fix up the directory permissions if
584 * required (do an access()).
586 if (lstat(name, &sb) == 0) {
587 *(spt++) = '/';
588 continue;
592 * the path fails at this point, see if we can create the
593 * needed directory and continue on
595 if (mkdir(name, S_IRWXU | S_IRWXG | S_IRWXO) < 0) {
596 *spt = '/';
597 retval = -1;
598 break;
602 * we were able to create the directory. We will tell the
603 * caller that we found something to fix, and it is ok to try
604 * and create the node again.
606 retval = 0;
607 if (pids)
608 set_ids(name, st_uid, st_gid);
611 * make sure the user doesn't have some strange umask that
612 * causes this newly created directory to be unusable. We fix
613 * the modes and restore them back to the creation default at
614 * the end of pax
616 if ((access(name, R_OK | W_OK | X_OK) < 0) &&
617 (lstat(name, &sb) == 0)) {
618 set_pmode(name, ((sb.st_mode & FILEBITS) | S_IRWXU));
619 add_dir(name, spt - name, &sb, 1);
621 *(spt++) = '/';
622 continue;
624 return(retval);
628 * set_ftime()
629 * Set the access time and modification time for a named file. If frc is
630 * non-zero we force these times to be set even if the user did not
631 * request access and/or modification time preservation (this is also
632 * used by -t to reset access times).
633 * When ign is zero, only those times the user has asked for are set, the
634 * other ones are left alone. We do not assume the un-documented feature
635 * of many utimes() implementations that consider a 0 time value as a do
636 * not set request.
639 void
640 set_ftime(char *fnm, time_t mtime, time_t atime, int frc)
642 static struct timeval tv[2] = {{0L, 0L}, {0L, 0L}};
643 struct stat sb;
645 tv[0].tv_sec = (long)atime;
646 tv[1].tv_sec = (long)mtime;
647 if (!frc && (!patime || !pmtime)) {
649 * if we are not forcing, only set those times the user wants
650 * set. We get the current values of the times if we need them.
652 if (lstat(fnm, &sb) == 0) {
653 if (!patime)
654 tv[0].tv_sec = (long)sb.st_atime;
655 if (!pmtime)
656 tv[1].tv_sec = (long)sb.st_mtime;
657 } else
658 syswarn(0,errno,"Unable to obtain file stats %s", fnm);
662 * set the times
664 if (utimes(fnm, tv) < 0)
665 syswarn(1, errno, "Access/modification time set failed on: %s",
666 fnm);
667 return;
671 * set_ids()
672 * set the uid and gid of a file system node
673 * Return:
674 * 0 when set, -1 on failure
678 set_ids(char *fnm, uid_t uid, gid_t gid)
680 if (chown(fnm, uid, gid) < 0) {
682 * ignore EPERM unless in verbose mode or being run by root.
683 * if running as pax, POSIX requires a warning.
685 if (strcmp(NM_PAX, argv0) == 0 || errno != EPERM || vflag ||
686 geteuid() == 0)
687 syswarn(1, errno, "Unable to set file uid/gid of %s",
688 fnm);
689 return(-1);
691 return(0);
695 * set_lids()
696 * set the uid and gid of a file system node
697 * Return:
698 * 0 when set, -1 on failure
702 set_lids(char *fnm, uid_t uid, gid_t gid)
704 if (lchown(fnm, uid, gid) < 0) {
706 * ignore EPERM unless in verbose mode or being run by root.
707 * if running as pax, POSIX requires a warning.
709 if (strcmp(NM_PAX, argv0) == 0 || errno != EPERM || vflag ||
710 geteuid() == 0)
711 syswarn(1, errno, "Unable to set file uid/gid of %s",
712 fnm);
713 return(-1);
715 return(0);
719 * set_pmode()
720 * Set file access mode
723 void
724 set_pmode(char *fnm, mode_t mode)
726 mode &= ABITS;
727 if (chmod(fnm, mode) < 0)
728 syswarn(1, errno, "Could not set permissions on %s", fnm);
729 return;
733 * file_write()
734 * Write/copy a file (during copy or archive extract). This routine knows
735 * how to copy files with lseek holes in it. (Which are read as file
736 * blocks containing all 0's but do not have any file blocks associated
737 * with the data). Typical examples of these are files created by dbm
738 * variants (.pag files). While the file size of these files are huge, the
739 * actual storage is quite small (the files are sparse). The problem is
740 * the holes read as all zeros so are probably stored on the archive that
741 * way (there is no way to determine if the file block is really a hole,
742 * we only know that a file block of all zero's can be a hole).
743 * At this writing, no major archive format knows how to archive files
744 * with holes. However, on extraction (or during copy, -rw) we have to
745 * deal with these files. Without detecting the holes, the files can
746 * consume a lot of file space if just written to disk. This replacement
747 * for write when passed the basic allocation size of a file system block,
748 * uses lseek whenever it detects the input data is all 0 within that
749 * file block. In more detail, the strategy is as follows:
750 * While the input is all zero keep doing an lseek. Keep track of when we
751 * pass over file block boundaries. Only write when we hit a non zero
752 * input. once we have written a file block, we continue to write it to
753 * the end (we stop looking at the input). When we reach the start of the
754 * next file block, start checking for zero blocks again. Working on file
755 * block boundaries significantly reduces the overhead when copying files
756 * that are NOT very sparse. This overhead (when compared to a write) is
757 * almost below the measurement resolution on many systems. Without it,
758 * files with holes cannot be safely copied. It does has a side effect as
759 * it can put holes into files that did not have them before, but that is
760 * not a problem since the file contents are unchanged (in fact it saves
761 * file space). (Except on paging files for diskless clients. But since we
762 * cannot determine one of those file from here, we ignore them). If this
763 * ever ends up on a system where CTG files are supported and the holes
764 * are not desired, just do a conditional test in those routines that
765 * call file_write() and have it call write() instead. BEFORE CLOSING THE
766 * FILE, make sure to call file_flush() when the last write finishes with
767 * an empty block. A lot of file systems will not create an lseek hole at
768 * the end. In this case we drop a single 0 at the end to force the
769 * trailing 0's in the file.
770 * ---Parameters---
771 * rem: how many bytes left in this file system block
772 * isempt: have we written to the file block yet (is it empty)
773 * sz: basic file block allocation size
774 * cnt: number of bytes on this write
775 * str: buffer to write
776 * Return:
777 * number of bytes written, -1 on write (or lseek) error.
781 file_write(int fd, char *str, int cnt, int *rem, int *isempt, int sz,
782 char *name)
784 char *pt;
785 char *end;
786 int wcnt;
787 char *st = str;
790 * while we have data to process
792 while (cnt) {
793 if (!*rem) {
795 * We are now at the start of file system block again
796 * (or what we think one is...). start looking for
797 * empty blocks again
799 *isempt = 1;
800 *rem = sz;
804 * only examine up to the end of the current file block or
805 * remaining characters to write, whatever is smaller
807 wcnt = MIN(cnt, *rem);
808 cnt -= wcnt;
809 *rem -= wcnt;
810 if (*isempt) {
812 * have not written to this block yet, so we keep
813 * looking for zero's
815 pt = st;
816 end = st + wcnt;
819 * look for a zero filled buffer
821 while ((pt < end) && (*pt == '\0'))
822 ++pt;
824 if (pt == end) {
826 * skip, buf is empty so far
828 if (lseek(fd, (off_t)wcnt, SEEK_CUR) < 0) {
829 syswarn(1,errno,"File seek on %s",
830 name);
831 return(-1);
833 st = pt;
834 continue;
837 * drat, the buf is not zero filled
839 *isempt = 0;
843 * have non-zero data in this file system block, have to write
845 if (write(fd, st, wcnt) != wcnt) {
846 syswarn(1, errno, "Failed write to file %s", name);
847 return(-1);
849 st += wcnt;
851 return(st - str);
855 * file_flush()
856 * when the last file block in a file is zero, many file systems will not
857 * let us create a hole at the end. To get the last block with zeros, we
858 * write the last BYTE with a zero (back up one byte and write a zero).
861 void
862 file_flush(int fd, char *fname, int isempt)
864 static char blnk[] = "\0";
867 * silly test, but make sure we are only called when the last block is
868 * filled with all zeros.
870 if (!isempt)
871 return;
874 * move back one byte and write a zero
876 if (lseek(fd, (off_t)-1, SEEK_CUR) < 0) {
877 syswarn(1, errno, "Failed seek on file %s", fname);
878 return;
881 if (write(fd, blnk, 1) < 0)
882 syswarn(1, errno, "Failed write to file %s", fname);
883 return;
887 * rdfile_close()
888 * close a file we have beed reading (to copy or archive). If we have to
889 * reset access time (tflag) do so (the times are stored in arcn).
892 void
893 rdfile_close(ARCHD *arcn, int *fd)
896 * make sure the file is open
898 if (*fd < 0)
899 return;
901 close(*fd);
902 *fd = -1;
903 if (!tflag)
904 return;
907 * user wants last access time reset
909 set_ftime(arcn->org_name, arcn->sb.st_mtime, arcn->sb.st_atime, 1);
910 return;
914 * set_crc()
915 * read a file to calculate its crc. This is a real drag. Archive formats
916 * that have this, end up reading the file twice (we have to write the
917 * header WITH the crc before writing the file contents. Oh well...
918 * Return:
919 * 0 if was able to calculate the crc, -1 otherwise
923 set_crc(ARCHD *arcn, int fd)
925 int i;
926 int res;
927 off_t cpcnt = 0L;
928 u_long size;
929 unsigned long crc = 0L;
930 char tbuf[FILEBLK];
931 struct stat sb;
933 if (fd < 0) {
935 * hmm, no fd, should never happen. well no crc then.
937 arcn->crc = 0L;
938 return(0);
941 if ((size = (u_long)arcn->sb.st_blksize) > (u_long)sizeof(tbuf))
942 size = (u_long)sizeof(tbuf);
945 * read all the bytes we think that there are in the file. If the user
946 * is trying to archive an active file, forget this file.
948 for(;;) {
949 if ((res = read(fd, tbuf, size)) <= 0)
950 break;
951 cpcnt += res;
952 for (i = 0; i < res; ++i)
953 crc += (tbuf[i] & 0xff);
957 * safety check. we want to avoid archiving files that are active as
958 * they can create inconsistent archive copies.
960 if (cpcnt != arcn->sb.st_size)
961 paxwarn(1, "File changed size %s", arcn->org_name);
962 else if (fstat(fd, &sb) < 0)
963 syswarn(1, errno, "Failed stat on %s", arcn->org_name);
964 else if (arcn->sb.st_mtime != sb.st_mtime)
965 paxwarn(1, "File %s was modified during read", arcn->org_name);
966 else if (lseek(fd, (off_t)0L, SEEK_SET) < 0)
967 syswarn(1, errno, "File rewind failed on: %s", arcn->org_name);
968 else {
969 arcn->crc = crc;
970 return(0);
972 return(-1);