2 * SPDX-License-Identifier: BSD-3-Clause
4 * Copyright (c) 1992 Keith Muller.
5 * Copyright (c) 1992, 1993
6 * The Regents of the University of California. All rights reserved.
8 * This code is derived from software contributed to Berkeley by
9 * Keith Muller of the University of California, San Diego.
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
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.
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
38 static char sccsid[] = "@(#)file_subs.c 8.1 (Berkeley) 5/31/93";
41 #include <sys/cdefs.h>
42 __FBSDID("$FreeBSD$");
44 #include <sys/types.h>
58 mk_link(char *,struct stat *,char *, int);
61 * routines that deal with file operations such as: creating, removing;
62 * and setting access modes, uid/gid and times of files
65 #define FILEBITS (S_ISVTX | S_IRWXU | S_IRWXG | S_IRWXO)
66 #define SETBITS (S_ISUID | S_ISGID)
67 #define ABITS (FILEBITS | SETBITS)
71 * Create and open a file.
73 * file descriptor or -1 for failure
77 file_creat(ARCHD *arcn)
84 * assume file doesn't exist, so just try to create it, most times this
85 * works. We have to take special handling when the file does exist. To
86 * detect this, we use O_EXCL. For example when trying to create a
87 * file and a character device or fifo exists with the same name, we
88 * can accidentally open the device by mistake (or block waiting to
89 * open). If we find that the open has failed, then spend the effort
90 * to figure out why. This strategy was found to have better average
91 * performance in common use than checking the file (and the path)
94 file_mode = arcn->sb.st_mode & FILEBITS;
95 if ((fd = open(arcn->name, O_WRONLY | O_CREAT | O_TRUNC | O_EXCL,
100 * the file seems to exist. First we try to get rid of it (found to be
101 * the second most common failure when traced). If this fails, only
102 * then we go to the expense to check and create the path to the file
104 if (unlnk_exist(arcn->name, arcn->type) != 0)
109 * try to open it again, if this fails, check all the nodes in
110 * the path and give it a final try. if chk_path() finds that
111 * it cannot fix anything, we will skip the last attempt
113 if ((fd = open(arcn->name, O_WRONLY | O_CREAT | O_TRUNC,
117 if (nodirs || chk_path(arcn->name,arcn->sb.st_uid,arcn->sb.st_gid) < 0) {
118 syswarn(1, oerrno, "Unable to create %s", arcn->name);
127 * Close file descriptor to a file just created by pax. Sets modes,
128 * ownership and times as required.
130 * 0 for success, -1 for failure
134 file_close(ARCHD *arcn, int fd)
141 syswarn(0, errno, "Unable to close file descriptor on %s",
145 * set owner/groups first as this may strip off mode bits we want
146 * then set file permission modes. Then set file access and
147 * modification times.
150 res = set_ids(arcn->name, arcn->sb.st_uid, arcn->sb.st_gid);
153 * IMPORTANT SECURITY NOTE:
154 * if not preserving mode or we cannot set uid/gid, then PROHIBIT
158 arcn->sb.st_mode &= ~(SETBITS);
160 set_pmode(arcn->name, arcn->sb.st_mode);
161 if (patime || pmtime)
162 set_ftime(arcn->name, arcn->sb.st_mtime, arcn->sb.st_atime, 0);
167 * Create a hard link to arcn->ln_name from arcn->name. arcn->ln_name
170 * 0 if ok, -1 otherwise
174 lnk_creat(ARCHD *arcn)
179 * we may be running as root, so we have to be sure that link target
180 * is not a directory, so we lstat and check
182 if (lstat(arcn->ln_name, &sb) < 0) {
183 syswarn(1,errno,"Unable to link to %s from %s", arcn->ln_name,
188 if (S_ISDIR(sb.st_mode)) {
189 paxwarn(1, "A hard link to the directory %s is not allowed",
194 return(mk_link(arcn->ln_name, &sb, arcn->name, 0));
199 * Create a hard link to arcn->org_name from arcn->name. Only used in copy
200 * with the -l flag. No warning or error if this does not succeed (we will
201 * then just create the file)
203 * 1 if copy() should try to create this file node
204 * 0 if cross_lnk() ok, -1 for fatal flaw (like linking to self).
208 cross_lnk(ARCHD *arcn)
211 * try to make a link to original file (-l flag in copy mode). make sure
212 * we do not try to link to directories in case we are running as root
213 * (and it might succeed).
215 if (arcn->type == PAX_DIR)
217 return(mk_link(arcn->org_name, &(arcn->sb), arcn->name, 1));
222 * In copy mode if we are not trying to make hard links between the src
223 * and destinations, make sure we are not going to overwrite ourselves by
224 * accident. This slows things down a little, but we have to protect all
225 * those people who make typing errors.
227 * 1 the target does not exist, go ahead and copy
228 * 0 skip it file exists (-k) or may be the same as source file
232 chk_same(ARCHD *arcn)
237 * if file does not exist, return. if file exists and -k, skip it
240 if (lstat(arcn->name, &sb) < 0)
246 * better make sure the user does not have src == dest by mistake
248 if ((arcn->sb.st_dev == sb.st_dev) && (arcn->sb.st_ino == sb.st_ino)) {
249 paxwarn(1, "Unable to copy %s, file would overwrite itself",
258 * try to make a hard link between two files. if ign set, we do not
261 * 0 if successful (or we are done with this file but no error, such as
262 * finding the from file exists and the user has set -k).
263 * 1 when ign was set to indicates we could not make the link but we
264 * should try to copy/extract the file as that might work (and is an
265 * allowed option). -1 an error occurred.
269 mk_link(char *to, struct stat *to_sb, char *from,
276 * if from file exists, it has to be unlinked to make the link. If the
277 * file exists and -k is set, skip it quietly
279 if (lstat(from, &sb) == 0) {
284 * make sure it is not the same file, protect the user
286 if ((to_sb->st_dev==sb.st_dev)&&(to_sb->st_ino == sb.st_ino)) {
287 paxwarn(1, "Unable to link file %s to itself", to);
292 * try to get rid of the file, based on the type
294 if (S_ISDIR(sb.st_mode)) {
295 if (rmdir(from) < 0) {
296 syswarn(1, errno, "Unable to remove %s", from);
299 } else if (unlink(from) < 0) {
301 syswarn(1, errno, "Unable to remove %s", from);
309 * from file is gone (or did not exist), try to make the hard link.
310 * if it fails, check the path and try it again (if chk_path() says to
314 if (link(to, from) == 0)
317 if (!nodirs && chk_path(from, to_sb->st_uid, to_sb->st_gid) == 0)
320 syswarn(1, oerrno, "Could not link to %s from %s", to,
328 * all right the link was made
335 * create an entry in the file system (other than a file or hard link).
336 * If successful, sets uid/gid modes and times as required.
338 * 0 if ok, -1 otherwise
342 node_creat(ARCHD *arcn)
352 * create node based on type, if that fails try to unlink the node and
353 * try again. finally check the path and try again. As noted in the
354 * file and link creation routines, this method seems to exhibit the
355 * best performance in general use workloads.
357 file_mode = arcn->sb.st_mode & FILEBITS;
362 res = mkdir(arcn->name, file_mode);
367 file_mode |= S_IFCHR;
368 res = mknod(arcn->name, file_mode, arcn->sb.st_rdev);
371 file_mode |= S_IFBLK;
372 res = mknod(arcn->name, file_mode, arcn->sb.st_rdev);
375 res = mkfifo(arcn->name, file_mode);
379 * Skip sockets, operation has no meaning under BSD
382 "%s skipped. Sockets cannot be copied or extracted",
386 res = symlink(arcn->ln_name, arcn->name);
394 * we should never get here
396 paxwarn(0, "%s has an unknown file type, skipping",
402 * if we were able to create the node break out of the loop,
403 * otherwise try to unlink the node and try again. if that
404 * fails check the full path and try a final time.
410 * we failed to make the node
413 if ((ign = unlnk_exist(arcn->name, arcn->type)) < 0)
419 if (nodirs || chk_path(arcn->name,arcn->sb.st_uid,arcn->sb.st_gid) < 0) {
420 syswarn(1, oerrno, "Could not create: %s", arcn->name);
426 * we were able to create the node. set uid/gid, modes and times
429 res = set_ids(arcn->name, arcn->sb.st_uid, arcn->sb.st_gid);
434 * IMPORTANT SECURITY NOTE:
435 * if not preserving mode or we cannot set uid/gid, then PROHIBIT any
439 arcn->sb.st_mode &= ~(SETBITS);
441 set_pmode(arcn->name, arcn->sb.st_mode);
443 if (arcn->type == PAX_DIR && strcmp(NM_CPIO, argv0) != 0) {
445 * Dirs must be processed again at end of extract to set times
446 * and modes to agree with those stored in the archive. However
447 * to allow extract to continue, we may have to also set owner
448 * rights. This allows nodes in the archive that are children
449 * of this directory to be extracted without failure. Both time
450 * and modes will be fixed after the entire archive is read and
453 if (access(arcn->name, R_OK | W_OK | X_OK) < 0) {
454 if (lstat(arcn->name, &sb) < 0) {
455 syswarn(0, errno,"Could not access %s (stat)",
457 set_pmode(arcn->name,file_mode | S_IRWXU);
460 * We have to add rights to the dir, so we make
461 * sure to restore the mode. The mode must be
462 * restored AS CREATED and not as stored if
465 set_pmode(arcn->name,
466 ((sb.st_mode & FILEBITS) | S_IRWXU));
468 arcn->sb.st_mode = sb.st_mode;
472 * we have to force the mode to what was set here,
473 * since we changed it from the default as created.
475 add_dir(arcn->name, arcn->nlen, &(arcn->sb), 1);
476 } else if (pmode || patime || pmtime)
477 add_dir(arcn->name, arcn->nlen, &(arcn->sb), 0);
480 if (patime || pmtime)
481 set_ftime(arcn->name, arcn->sb.st_mtime, arcn->sb.st_atime, 0);
487 * Remove node from file system with the specified name. We pass the type
488 * of the node that is going to replace it. When we try to create a
489 * directory and find that it already exists, we allow processing to
490 * continue as proper modes etc will always be set for it later on.
492 * 0 is ok to proceed, no file with the specified name exists
493 * -1 we were unable to remove the node, or we should not remove it (-k)
494 * 1 we found a directory and we were going to create a directory.
498 unlnk_exist(char *name, int type)
503 * the file does not exist, or -k we are done
505 if (lstat(name, &sb) < 0)
510 if (S_ISDIR(sb.st_mode)) {
512 * try to remove a directory, if it fails and we were going to
513 * create a directory anyway, tell the caller (return a 1)
515 if (rmdir(name) < 0) {
518 syswarn(1,errno,"Unable to remove directory %s", name);
525 * try to get rid of all non-directory type nodes
527 if (unlink(name) < 0) {
528 syswarn(1, errno, "Could not unlink %s", name);
536 * We were trying to create some kind of node in the file system and it
537 * failed. chk_path() makes sure the path up to the node exists and is
538 * writeable. When we have to create a directory that is missing along the
539 * path somewhere, the directory we create will be set to the same
540 * uid/gid as the file has (when uid and gid are being preserved).
541 * NOTE: this routine is a real performance loss. It is only used as a
542 * last resort when trying to create entries in the file system.
544 * -1 when it could find nothing it is allowed to fix.
549 chk_path( char *name, uid_t st_uid, gid_t st_gid)
556 * watch out for paths with nodes stored directly in / (e.g. /bozo)
563 * work forward from the first / and check each part of the path
565 spt = strchr(spt, '/');
571 * if it exists we assume it is a directory, it is not within
572 * the spec (at least it seems to read that way) to alter the
573 * file system for nodes NOT EXPLICITLY stored on the archive.
574 * If that assumption is changed, you would test the node here
575 * and figure out how to get rid of it (probably like some
576 * recursive unlink()) or fix up the directory permissions if
577 * required (do an access()).
579 if (lstat(name, &sb) == 0) {
585 * the path fails at this point, see if we can create the
586 * needed directory and continue on
588 if (mkdir(name, S_IRWXU | S_IRWXG | S_IRWXO) < 0) {
595 * we were able to create the directory. We will tell the
596 * caller that we found something to fix, and it is ok to try
597 * and create the node again.
601 (void)set_ids(name, st_uid, st_gid);
604 * make sure the user doesn't have some strange umask that
605 * causes this newly created directory to be unusable. We fix
606 * the modes and restore them back to the creation default at
609 if ((access(name, R_OK | W_OK | X_OK) < 0) &&
610 (lstat(name, &sb) == 0)) {
611 set_pmode(name, ((sb.st_mode & FILEBITS) | S_IRWXU));
612 add_dir(name, spt - name, &sb, 1);
622 * Set the access time and modification time for a named file. If frc is
623 * non-zero we force these times to be set even if the user did not
624 * request access and/or modification time preservation (this is also
625 * used by -t to reset access times).
626 * When ign is zero, only those times the user has asked for are set, the
627 * other ones are left alone. We do not assume the un-documented feature
628 * of many lutimes() implementations that consider a 0 time value as a do
633 set_ftime(char *fnm, time_t mtime, time_t atime, int frc)
635 static struct timeval tv[2] = {{0L, 0L}, {0L, 0L}};
638 tv[0].tv_sec = atime;
639 tv[1].tv_sec = mtime;
640 if (!frc && (!patime || !pmtime)) {
642 * if we are not forcing, only set those times the user wants
643 * set. We get the current values of the times if we need them.
645 if (lstat(fnm, &sb) == 0) {
647 tv[0].tv_sec = sb.st_atime;
649 tv[1].tv_sec = sb.st_mtime;
651 syswarn(0,errno,"Unable to obtain file stats %s", fnm);
657 if (lutimes(fnm, tv) < 0)
658 syswarn(1, errno, "Access/modification time set failed on: %s",
665 * set the uid and gid of a file system node
667 * 0 when set, -1 on failure
671 set_ids(char *fnm, uid_t uid, gid_t gid)
673 if (lchown(fnm, uid, gid) < 0) {
675 * ignore EPERM unless in verbose mode or being run by root.
676 * if running as pax, POSIX requires a warning.
678 if (strcmp(NM_PAX, argv0) == 0 || errno != EPERM || vflag ||
680 syswarn(1, errno, "Unable to set file uid/gid of %s",
689 * Set file access mode
693 set_pmode(char *fnm, mode_t mode)
696 if (lchmod(fnm, mode) < 0)
697 syswarn(1, errno, "Could not set permissions on %s", fnm);
703 * Write/copy a file (during copy or archive extract). This routine knows
704 * how to copy files with lseek holes in it. (Which are read as file
705 * blocks containing all 0's but do not have any file blocks associated
706 * with the data). Typical examples of these are files created by dbm
707 * variants (.pag files). While the file size of these files are huge, the
708 * actual storage is quite small (the files are sparse). The problem is
709 * the holes read as all zeros so are probably stored on the archive that
710 * way (there is no way to determine if the file block is really a hole,
711 * we only know that a file block of all zero's can be a hole).
712 * At this writing, no major archive format knows how to archive files
713 * with holes. However, on extraction (or during copy, -rw) we have to
714 * deal with these files. Without detecting the holes, the files can
715 * consume a lot of file space if just written to disk. This replacement
716 * for write when passed the basic allocation size of a file system block,
717 * uses lseek whenever it detects the input data is all 0 within that
718 * file block. In more detail, the strategy is as follows:
719 * While the input is all zero keep doing an lseek. Keep track of when we
720 * pass over file block boundaries. Only write when we hit a non zero
721 * input. once we have written a file block, we continue to write it to
722 * the end (we stop looking at the input). When we reach the start of the
723 * next file block, start checking for zero blocks again. Working on file
724 * block boundaries significantly reduces the overhead when copying files
725 * that are NOT very sparse. This overhead (when compared to a write) is
726 * almost below the measurement resolution on many systems. Without it,
727 * files with holes cannot be safely copied. It does has a side effect as
728 * it can put holes into files that did not have them before, but that is
729 * not a problem since the file contents are unchanged (in fact it saves
730 * file space). (Except on paging files for diskless clients. But since we
731 * cannot determine one of those file from here, we ignore them). If this
732 * ever ends up on a system where CTG files are supported and the holes
733 * are not desired, just do a conditional test in those routines that
734 * call file_write() and have it call write() instead. BEFORE CLOSING THE
735 * FILE, make sure to call file_flush() when the last write finishes with
736 * an empty block. A lot of file systems will not create an lseek hole at
737 * the end. In this case we drop a single 0 at the end to force the
738 * trailing 0's in the file.
740 * rem: how many bytes left in this file system block
741 * isempt: have we written to the file block yet (is it empty)
742 * sz: basic file block allocation size
743 * cnt: number of bytes on this write
744 * str: buffer to write
746 * number of bytes written, -1 on write (or lseek) error.
750 file_write(int fd, char *str, int cnt, int *rem, int *isempt, int sz,
759 * while we have data to process
764 * We are now at the start of file system block again
765 * (or what we think one is...). start looking for
773 * only examine up to the end of the current file block or
774 * remaining characters to write, whatever is smaller
776 wcnt = MIN(cnt, *rem);
781 * have not written to this block yet, so we keep
788 * look for a zero filled buffer
790 while ((pt < end) && (*pt == '\0'))
795 * skip, buf is empty so far
797 if (lseek(fd, (off_t)wcnt, SEEK_CUR) < 0) {
798 syswarn(1,errno,"File seek on %s",
806 * drat, the buf is not zero filled
812 * have non-zero data in this file system block, have to write
814 if (write(fd, st, wcnt) != wcnt) {
815 syswarn(1, errno, "Failed write to file %s", name);
825 * when the last file block in a file is zero, many file systems will not
826 * let us create a hole at the end. To get the last block with zeros, we
827 * write the last BYTE with a zero (back up one byte and write a zero).
831 file_flush(int fd, char *fname, int isempt)
833 static char blnk[] = "\0";
836 * silly test, but make sure we are only called when the last block is
837 * filled with all zeros.
843 * move back one byte and write a zero
845 if (lseek(fd, (off_t)-1, SEEK_CUR) < 0) {
846 syswarn(1, errno, "Failed seek on file %s", fname);
850 if (write(fd, blnk, 1) < 0)
851 syswarn(1, errno, "Failed write to file %s", fname);
857 * close a file we have beed reading (to copy or archive). If we have to
858 * reset access time (tflag) do so (the times are stored in arcn).
862 rdfile_close(ARCHD *arcn, int *fd)
865 * make sure the file is open
876 * user wants last access time reset
878 set_ftime(arcn->org_name, arcn->sb.st_mtime, arcn->sb.st_atime, 1);
884 * read a file to calculate its crc. This is a real drag. Archive formats
885 * that have this, end up reading the file twice (we have to write the
886 * header WITH the crc before writing the file contents. Oh well...
888 * 0 if was able to calculate the crc, -1 otherwise
892 set_crc(ARCHD *arcn, int fd)
898 unsigned long crc = 0L;
904 * hmm, no fd, should never happen. well no crc then.
910 if ((size = (u_long)arcn->sb.st_blksize) > (u_long)sizeof(tbuf))
911 size = (u_long)sizeof(tbuf);
914 * read all the bytes we think that there are in the file. If the user
915 * is trying to archive an active file, forget this file.
918 if ((res = read(fd, tbuf, size)) <= 0)
921 for (i = 0; i < res; ++i)
922 crc += (tbuf[i] & 0xff);
926 * safety check. we want to avoid archiving files that are active as
927 * they can create inconsistent archive copies.
929 if (cpcnt != arcn->sb.st_size)
930 paxwarn(1, "File changed size %s", arcn->org_name);
931 else if (fstat(fd, &sb) < 0)
932 syswarn(1, errno, "Failed stat on %s", arcn->org_name);
933 else if (arcn->sb.st_mtime != sb.st_mtime)
934 paxwarn(1, "File %s was modified during read", arcn->org_name);
935 else if (lseek(fd, (off_t)0L, SEEK_SET) < 0)
936 syswarn(1, errno, "File rewind failed on: %s", arcn->org_name);