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
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 * 4. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 static char sccsid[] = "@(#)file_subs.c 8.1 (Berkeley) 5/31/93";
39 #include <sys/cdefs.h>
40 __FBSDID("$FreeBSD$");
42 #include <sys/types.h>
56 mk_link(char *,struct stat *,char *, int);
59 * routines that deal with file operations such as: creating, removing;
60 * and setting access modes, uid/gid and times of files
63 #define FILEBITS (S_ISVTX | S_IRWXU | S_IRWXG | S_IRWXO)
64 #define SETBITS (S_ISUID | S_ISGID)
65 #define ABITS (FILEBITS | SETBITS)
69 * Create and open a file.
71 * file descriptor or -1 for failure
75 file_creat(ARCHD *arcn)
82 * assume file doesn't exist, so just try to create it, most times this
83 * works. We have to take special handling when the file does exist. To
84 * detect this, we use O_EXCL. For example when trying to create a
85 * file and a character device or fifo exists with the same name, we
86 * can accidentally open the device by mistake (or block waiting to
87 * open). If we find that the open has failed, then spend the effort
88 * to figure out why. This strategy was found to have better average
89 * performance in common use than checking the file (and the path)
92 file_mode = arcn->sb.st_mode & FILEBITS;
93 if ((fd = open(arcn->name, O_WRONLY | O_CREAT | O_TRUNC | O_EXCL,
98 * the file seems to exist. First we try to get rid of it (found to be
99 * the second most common failure when traced). If this fails, only
100 * then we go to the expense to check and create the path to the file
102 if (unlnk_exist(arcn->name, arcn->type) != 0)
107 * try to open it again, if this fails, check all the nodes in
108 * the path and give it a final try. if chk_path() finds that
109 * it cannot fix anything, we will skip the last attempt
111 if ((fd = open(arcn->name, O_WRONLY | O_CREAT | O_TRUNC,
115 if (nodirs || chk_path(arcn->name,arcn->sb.st_uid,arcn->sb.st_gid) < 0) {
116 syswarn(1, oerrno, "Unable to create %s", arcn->name);
125 * Close file descriptor to a file just created by pax. Sets modes,
126 * ownership and times as required.
128 * 0 for success, -1 for failure
132 file_close(ARCHD *arcn, int fd)
139 syswarn(0, errno, "Unable to close file descriptor on %s",
143 * set owner/groups first as this may strip off mode bits we want
144 * then set file permission modes. Then set file access and
145 * modification times.
148 res = set_ids(arcn->name, arcn->sb.st_uid, arcn->sb.st_gid);
151 * IMPORTANT SECURITY NOTE:
152 * if not preserving mode or we cannot set uid/gid, then PROHIBIT
156 arcn->sb.st_mode &= ~(SETBITS);
158 set_pmode(arcn->name, arcn->sb.st_mode);
159 if (patime || pmtime)
160 set_ftime(arcn->name, arcn->sb.st_mtime, arcn->sb.st_atime, 0);
165 * Create a hard link to arcn->ln_name from arcn->name. arcn->ln_name
168 * 0 if ok, -1 otherwise
172 lnk_creat(ARCHD *arcn)
177 * we may be running as root, so we have to be sure that link target
178 * is not a directory, so we lstat and check
180 if (lstat(arcn->ln_name, &sb) < 0) {
181 syswarn(1,errno,"Unable to link to %s from %s", arcn->ln_name,
186 if (S_ISDIR(sb.st_mode)) {
187 paxwarn(1, "A hard link to the directory %s is not allowed",
192 return(mk_link(arcn->ln_name, &sb, arcn->name, 0));
197 * Create a hard link to arcn->org_name from arcn->name. Only used in copy
198 * with the -l flag. No warning or error if this does not succeed (we will
199 * then just create the file)
201 * 1 if copy() should try to create this file node
202 * 0 if cross_lnk() ok, -1 for fatal flaw (like linking to self).
206 cross_lnk(ARCHD *arcn)
209 * try to make a link to original file (-l flag in copy mode). make sure
210 * we do not try to link to directories in case we are running as root
211 * (and it might succeed).
213 if (arcn->type == PAX_DIR)
215 return(mk_link(arcn->org_name, &(arcn->sb), arcn->name, 1));
220 * In copy mode if we are not trying to make hard links between the src
221 * and destinations, make sure we are not going to overwrite ourselves by
222 * accident. This slows things down a little, but we have to protect all
223 * those people who make typing errors.
225 * 1 the target does not exist, go ahead and copy
226 * 0 skip it file exists (-k) or may be the same as source file
230 chk_same(ARCHD *arcn)
235 * if file does not exist, return. if file exists and -k, skip it
238 if (lstat(arcn->name, &sb) < 0)
244 * better make sure the user does not have src == dest by mistake
246 if ((arcn->sb.st_dev == sb.st_dev) && (arcn->sb.st_ino == sb.st_ino)) {
247 paxwarn(1, "Unable to copy %s, file would overwrite itself",
256 * try to make a hard link between two files. if ign set, we do not
259 * 0 if successful (or we are done with this file but no error, such as
260 * finding the from file exists and the user has set -k).
261 * 1 when ign was set to indicates we could not make the link but we
262 * should try to copy/extract the file as that might work (and is an
263 * allowed option). -1 an error occurred.
267 mk_link(char *to, struct stat *to_sb, char *from,
274 * if from file exists, it has to be unlinked to make the link. If the
275 * file exists and -k is set, skip it quietly
277 if (lstat(from, &sb) == 0) {
282 * make sure it is not the same file, protect the user
284 if ((to_sb->st_dev==sb.st_dev)&&(to_sb->st_ino == sb.st_ino)) {
285 paxwarn(1, "Unable to link file %s to itself", to);
290 * try to get rid of the file, based on the type
292 if (S_ISDIR(sb.st_mode)) {
293 if (rmdir(from) < 0) {
294 syswarn(1, errno, "Unable to remove %s", from);
297 } else if (unlink(from) < 0) {
299 syswarn(1, errno, "Unable to remove %s", from);
307 * from file is gone (or did not exist), try to make the hard link.
308 * if it fails, check the path and try it again (if chk_path() says to
312 if (link(to, from) == 0)
315 if (!nodirs && chk_path(from, to_sb->st_uid, to_sb->st_gid) == 0)
318 syswarn(1, oerrno, "Could not link to %s from %s", to,
326 * all right the link was made
333 * create an entry in the file system (other than a file or hard link).
334 * If successful, sets uid/gid modes and times as required.
336 * 0 if ok, -1 otherwise
340 node_creat(ARCHD *arcn)
350 * create node based on type, if that fails try to unlink the node and
351 * try again. finally check the path and try again. As noted in the
352 * file and link creation routines, this method seems to exhibit the
353 * best performance in general use workloads.
355 file_mode = arcn->sb.st_mode & FILEBITS;
360 res = mkdir(arcn->name, file_mode);
365 file_mode |= S_IFCHR;
366 res = mknod(arcn->name, file_mode, arcn->sb.st_rdev);
369 file_mode |= S_IFBLK;
370 res = mknod(arcn->name, file_mode, arcn->sb.st_rdev);
373 res = mkfifo(arcn->name, file_mode);
377 * Skip sockets, operation has no meaning under BSD
380 "%s skipped. Sockets cannot be copied or extracted",
384 res = symlink(arcn->ln_name, arcn->name);
392 * we should never get here
394 paxwarn(0, "%s has an unknown file type, skipping",
400 * if we were able to create the node break out of the loop,
401 * otherwise try to unlink the node and try again. if that
402 * fails check the full path and try a final time.
408 * we failed to make the node
411 if ((ign = unlnk_exist(arcn->name, arcn->type)) < 0)
417 if (nodirs || chk_path(arcn->name,arcn->sb.st_uid,arcn->sb.st_gid) < 0) {
418 syswarn(1, oerrno, "Could not create: %s", arcn->name);
424 * we were able to create the node. set uid/gid, modes and times
427 res = set_ids(arcn->name, arcn->sb.st_uid, arcn->sb.st_gid);
432 * IMPORTANT SECURITY NOTE:
433 * if not preserving mode or we cannot set uid/gid, then PROHIBIT any
437 arcn->sb.st_mode &= ~(SETBITS);
439 set_pmode(arcn->name, arcn->sb.st_mode);
441 if (arcn->type == PAX_DIR && strcmp(NM_CPIO, argv0) != 0) {
443 * Dirs must be processed again at end of extract to set times
444 * and modes to agree with those stored in the archive. However
445 * to allow extract to continue, we may have to also set owner
446 * rights. This allows nodes in the archive that are children
447 * of this directory to be extracted without failure. Both time
448 * and modes will be fixed after the entire archive is read and
451 if (access(arcn->name, R_OK | W_OK | X_OK) < 0) {
452 if (lstat(arcn->name, &sb) < 0) {
453 syswarn(0, errno,"Could not access %s (stat)",
455 set_pmode(arcn->name,file_mode | S_IRWXU);
458 * We have to add rights to the dir, so we make
459 * sure to restore the mode. The mode must be
460 * restored AS CREATED and not as stored if
463 set_pmode(arcn->name,
464 ((sb.st_mode & FILEBITS) | S_IRWXU));
466 arcn->sb.st_mode = sb.st_mode;
470 * we have to force the mode to what was set here,
471 * since we changed it from the default as created.
473 add_dir(arcn->name, arcn->nlen, &(arcn->sb), 1);
474 } else if (pmode || patime || pmtime)
475 add_dir(arcn->name, arcn->nlen, &(arcn->sb), 0);
478 if (patime || pmtime)
479 set_ftime(arcn->name, arcn->sb.st_mtime, arcn->sb.st_atime, 0);
485 * Remove node from file system with the specified name. We pass the type
486 * of the node that is going to replace it. When we try to create a
487 * directory and find that it already exists, we allow processing to
488 * continue as proper modes etc will always be set for it later on.
490 * 0 is ok to proceed, no file with the specified name exists
491 * -1 we were unable to remove the node, or we should not remove it (-k)
492 * 1 we found a directory and we were going to create a directory.
496 unlnk_exist(char *name, int type)
501 * the file does not exist, or -k we are done
503 if (lstat(name, &sb) < 0)
508 if (S_ISDIR(sb.st_mode)) {
510 * try to remove a directory, if it fails and we were going to
511 * create a directory anyway, tell the caller (return a 1)
513 if (rmdir(name) < 0) {
516 syswarn(1,errno,"Unable to remove directory %s", name);
523 * try to get rid of all non-directory type nodes
525 if (unlink(name) < 0) {
526 syswarn(1, errno, "Could not unlink %s", name);
534 * We were trying to create some kind of node in the file system and it
535 * failed. chk_path() makes sure the path up to the node exists and is
536 * writeable. When we have to create a directory that is missing along the
537 * path somewhere, the directory we create will be set to the same
538 * uid/gid as the file has (when uid and gid are being preserved).
539 * NOTE: this routine is a real performance loss. It is only used as a
540 * last resort when trying to create entries in the file system.
542 * -1 when it could find nothing it is allowed to fix.
547 chk_path( char *name, uid_t st_uid, gid_t st_gid)
554 * watch out for paths with nodes stored directly in / (e.g. /bozo)
561 * work forward from the first / and check each part of the path
563 spt = strchr(spt, '/');
569 * if it exists we assume it is a directory, it is not within
570 * the spec (at least it seems to read that way) to alter the
571 * file system for nodes NOT EXPLICITLY stored on the archive.
572 * If that assumption is changed, you would test the node here
573 * and figure out how to get rid of it (probably like some
574 * recursive unlink()) or fix up the directory permissions if
575 * required (do an access()).
577 if (lstat(name, &sb) == 0) {
583 * the path fails at this point, see if we can create the
584 * needed directory and continue on
586 if (mkdir(name, S_IRWXU | S_IRWXG | S_IRWXO) < 0) {
593 * we were able to create the directory. We will tell the
594 * caller that we found something to fix, and it is ok to try
595 * and create the node again.
599 (void)set_ids(name, st_uid, st_gid);
602 * make sure the user doesn't have some strange umask that
603 * causes this newly created directory to be unusable. We fix
604 * the modes and restore them back to the creation default at
607 if ((access(name, R_OK | W_OK | X_OK) < 0) &&
608 (lstat(name, &sb) == 0)) {
609 set_pmode(name, ((sb.st_mode & FILEBITS) | S_IRWXU));
610 add_dir(name, spt - name, &sb, 1);
620 * Set the access time and modification time for a named file. If frc is
621 * non-zero we force these times to be set even if the user did not
622 * request access and/or modification time preservation (this is also
623 * used by -t to reset access times).
624 * When ign is zero, only those times the user has asked for are set, the
625 * other ones are left alone. We do not assume the un-documented feature
626 * of many lutimes() implementations that consider a 0 time value as a do
631 set_ftime(char *fnm, time_t mtime, time_t atime, int frc)
633 static struct timeval tv[2] = {{0L, 0L}, {0L, 0L}};
636 tv[0].tv_sec = atime;
637 tv[1].tv_sec = mtime;
638 if (!frc && (!patime || !pmtime)) {
640 * if we are not forcing, only set those times the user wants
641 * set. We get the current values of the times if we need them.
643 if (lstat(fnm, &sb) == 0) {
645 tv[0].tv_sec = sb.st_atime;
647 tv[1].tv_sec = sb.st_mtime;
649 syswarn(0,errno,"Unable to obtain file stats %s", fnm);
655 if (lutimes(fnm, tv) < 0)
656 syswarn(1, errno, "Access/modification time set failed on: %s",
663 * set the uid and gid of a file system node
665 * 0 when set, -1 on failure
669 set_ids(char *fnm, uid_t uid, gid_t gid)
671 if (lchown(fnm, uid, gid) < 0) {
673 * ignore EPERM unless in verbose mode or being run by root.
674 * if running as pax, POSIX requires a warning.
676 if (strcmp(NM_PAX, argv0) == 0 || errno != EPERM || vflag ||
678 syswarn(1, errno, "Unable to set file uid/gid of %s",
687 * Set file access mode
691 set_pmode(char *fnm, mode_t mode)
694 if (lchmod(fnm, mode) < 0)
695 syswarn(1, errno, "Could not set permissions on %s", fnm);
701 * Write/copy a file (during copy or archive extract). This routine knows
702 * how to copy files with lseek holes in it. (Which are read as file
703 * blocks containing all 0's but do not have any file blocks associated
704 * with the data). Typical examples of these are files created by dbm
705 * variants (.pag files). While the file size of these files are huge, the
706 * actual storage is quite small (the files are sparse). The problem is
707 * the holes read as all zeros so are probably stored on the archive that
708 * way (there is no way to determine if the file block is really a hole,
709 * we only know that a file block of all zero's can be a hole).
710 * At this writing, no major archive format knows how to archive files
711 * with holes. However, on extraction (or during copy, -rw) we have to
712 * deal with these files. Without detecting the holes, the files can
713 * consume a lot of file space if just written to disk. This replacement
714 * for write when passed the basic allocation size of a file system block,
715 * uses lseek whenever it detects the input data is all 0 within that
716 * file block. In more detail, the strategy is as follows:
717 * While the input is all zero keep doing an lseek. Keep track of when we
718 * pass over file block boundaries. Only write when we hit a non zero
719 * input. once we have written a file block, we continue to write it to
720 * the end (we stop looking at the input). When we reach the start of the
721 * next file block, start checking for zero blocks again. Working on file
722 * block boundaries significantly reduces the overhead when copying files
723 * that are NOT very sparse. This overhead (when compared to a write) is
724 * almost below the measurement resolution on many systems. Without it,
725 * files with holes cannot be safely copied. It does has a side effect as
726 * it can put holes into files that did not have them before, but that is
727 * not a problem since the file contents are unchanged (in fact it saves
728 * file space). (Except on paging files for diskless clients. But since we
729 * cannot determine one of those file from here, we ignore them). If this
730 * ever ends up on a system where CTG files are supported and the holes
731 * are not desired, just do a conditional test in those routines that
732 * call file_write() and have it call write() instead. BEFORE CLOSING THE
733 * FILE, make sure to call file_flush() when the last write finishes with
734 * an empty block. A lot of file systems will not create an lseek hole at
735 * the end. In this case we drop a single 0 at the end to force the
736 * trailing 0's in the file.
738 * rem: how many bytes left in this file system block
739 * isempt: have we written to the file block yet (is it empty)
740 * sz: basic file block allocation size
741 * cnt: number of bytes on this write
742 * str: buffer to write
744 * number of bytes written, -1 on write (or lseek) error.
748 file_write(int fd, char *str, int cnt, int *rem, int *isempt, int sz,
757 * while we have data to process
762 * We are now at the start of file system block again
763 * (or what we think one is...). start looking for
771 * only examine up to the end of the current file block or
772 * remaining characters to write, whatever is smaller
774 wcnt = MIN(cnt, *rem);
779 * have not written to this block yet, so we keep
786 * look for a zero filled buffer
788 while ((pt < end) && (*pt == '\0'))
793 * skip, buf is empty so far
795 if (lseek(fd, (off_t)wcnt, SEEK_CUR) < 0) {
796 syswarn(1,errno,"File seek on %s",
804 * drat, the buf is not zero filled
810 * have non-zero data in this file system block, have to write
812 if (write(fd, st, wcnt) != wcnt) {
813 syswarn(1, errno, "Failed write to file %s", name);
823 * when the last file block in a file is zero, many file systems will not
824 * let us create a hole at the end. To get the last block with zeros, we
825 * write the last BYTE with a zero (back up one byte and write a zero).
829 file_flush(int fd, char *fname, int isempt)
831 static char blnk[] = "\0";
834 * silly test, but make sure we are only called when the last block is
835 * filled with all zeros.
841 * move back one byte and write a zero
843 if (lseek(fd, (off_t)-1, SEEK_CUR) < 0) {
844 syswarn(1, errno, "Failed seek on file %s", fname);
848 if (write(fd, blnk, 1) < 0)
849 syswarn(1, errno, "Failed write to file %s", fname);
855 * close a file we have beed reading (to copy or archive). If we have to
856 * reset access time (tflag) do so (the times are stored in arcn).
860 rdfile_close(ARCHD *arcn, int *fd)
863 * make sure the file is open
874 * user wants last access time reset
876 set_ftime(arcn->org_name, arcn->sb.st_mtime, arcn->sb.st_atime, 1);
882 * read a file to calculate its crc. This is a real drag. Archive formats
883 * that have this, end up reading the file twice (we have to write the
884 * header WITH the crc before writing the file contents. Oh well...
886 * 0 if was able to calculate the crc, -1 otherwise
890 set_crc(ARCHD *arcn, int fd)
896 unsigned long crc = 0L;
902 * hmm, no fd, should never happen. well no crc then.
908 if ((size = (u_long)arcn->sb.st_blksize) > (u_long)sizeof(tbuf))
909 size = (u_long)sizeof(tbuf);
912 * read all the bytes we think that there are in the file. If the user
913 * is trying to archive an active file, forget this file.
916 if ((res = read(fd, tbuf, size)) <= 0)
919 for (i = 0; i < res; ++i)
920 crc += (tbuf[i] & 0xff);
924 * safety check. we want to avoid archiving files that are active as
925 * they can create inconsistent archive copies.
927 if (cpcnt != arcn->sb.st_size)
928 paxwarn(1, "File changed size %s", arcn->org_name);
929 else if (fstat(fd, &sb) < 0)
930 syswarn(1, errno, "Failed stat on %s", arcn->org_name);
931 else if (arcn->sb.st_mtime != sb.st_mtime)
932 paxwarn(1, "File %s was modified during read", arcn->org_name);
933 else if (lseek(fd, (off_t)0L, SEEK_SET) < 0)
934 syswarn(1, errno, "File rewind failed on: %s", arcn->org_name);