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 * 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
37 * @(#)ar_subs.c 8.2 (Berkeley) 4/18/94
38 * $FreeBSD: src/bin/pax/ar_subs.c,v 1.13.2.1 2001/08/01 05:03:11 obrien Exp $
39 * $DragonFly: src/bin/pax/ar_subs.c,v 1.3 2003/09/21 04:24:16 drhodus Exp $
42 #include <sys/types.h>
55 static void wr_archive (register ARCHD *, int is_app);
56 static int get_arc (void);
57 static int next_head (register ARCHD *);
58 extern sigset_t s_mask;
61 * Routines which control the overall operation modes of pax as specified by
62 * the user: list, append, read ...
65 static char hdbuf[BLKMULT]; /* space for archive header on read */
66 u_long flcnt; /* number of files processed */
70 * list the contents of an archive which match user supplied pattern(s)
71 * (no pattern matches all).
89 * figure out archive type; pass any format specific options to the
90 * archive option processing routine; call the format init routine. We
91 * also save current time for ls_list() so we do not make a system
92 * call for each file we need to print. If verbose (vflag) start up
93 * the name and group caches.
95 if ((get_arc() < 0) || ((*frmt->options)() < 0) ||
96 ((*frmt->st_rd)() < 0))
99 if (vflag && ((uidtb_start() < 0) || (gidtb_start() < 0)))
105 * step through the archive until the format says it is done
107 while (next_head(arcn) == 0) {
109 * check for pattern, and user specified options match.
110 * When all patterns are matched we are done.
112 if ((res = pat_match(arcn)) < 0)
115 if ((res == 0) && (sel_chk(arcn) == 0)) {
117 * pattern resulted in a selected file
119 if (pat_sel(arcn) < 0)
123 * modify the name as requested by the user if name
124 * survives modification, do a listing of the file
126 if ((res = mod_name(arcn)) < 0)
129 ls_list(arcn, now, stdout);
133 * skip to next archive format header using values calculated
134 * by the format header read routine
136 if (rd_skip(arcn->skip + arcn->pad) == 1)
141 * all done, let format have a chance to cleanup, and make sure that
142 * the patterns supplied by the user were all matched
144 (void)(*frmt->end_rd)();
145 (void)sigprocmask(SIG_BLOCK, &s_mask, NULL);
152 * extract the member(s) of an archive as specified by user supplied
153 * pattern(s) (no patterns extracts all members)
164 register ARCHD *arcn;
174 * figure out archive type; pass any format specific options to the
175 * archive option processing routine; call the format init routine;
176 * start up the directory modification time and access mode database
178 if ((get_arc() < 0) || ((*frmt->options)() < 0) ||
179 ((*frmt->st_rd)() < 0) || (dir_start() < 0))
183 * When we are doing interactive rename, we store the mapping of names
184 * so we can fix up hard links files later in the archive.
186 if (iflag && (name_start() < 0))
192 * step through each entry on the archive until the format read routine
195 while (next_head(arcn) == 0) {
198 * check for pattern, and user specified options match. When
199 * all the patterns are matched we are done
201 if ((res = pat_match(arcn)) < 0)
204 if ((res > 0) || (sel_chk(arcn) != 0)) {
206 * file is not selected. skip past any file data and
207 * padding and go back for the next archive member
209 (void)rd_skip(arcn->skip + arcn->pad);
214 * with -u or -D only extract when the archive member is newer
215 * than the file with the same name in the file system (nos
216 * test of being the same type is required).
217 * NOTE: this test is done BEFORE name modifications as
218 * specified by pax. this operation can be confusing to the
219 * user who might expect the test to be done on an existing
220 * file AFTER the name mod. In honesty the pax spec is probably
221 * flawed in this respect.
223 if ((uflag || Dflag) && ((lstat(arcn->name, &sb) == 0))) {
224 if (uflag && Dflag) {
225 if ((arcn->sb.st_mtime <= sb.st_mtime) &&
226 (arcn->sb.st_ctime <= sb.st_ctime)) {
227 (void)rd_skip(arcn->skip + arcn->pad);
231 if (arcn->sb.st_ctime <= sb.st_ctime) {
232 (void)rd_skip(arcn->skip + arcn->pad);
235 } else if (arcn->sb.st_mtime <= sb.st_mtime) {
236 (void)rd_skip(arcn->skip + arcn->pad);
242 * this archive member is now been selected. modify the name.
244 if ((pat_sel(arcn) < 0) || ((res = mod_name(arcn)) < 0))
248 * a bad name mod, skip and purge name from link table
251 (void)rd_skip(arcn->skip + arcn->pad);
256 * Non standard -Y and -Z flag. When the existing file is
257 * same age or newer skip
259 if ((Yflag || Zflag) && ((lstat(arcn->name, &sb) == 0))) {
260 if (Yflag && Zflag) {
261 if ((arcn->sb.st_mtime <= sb.st_mtime) &&
262 (arcn->sb.st_ctime <= sb.st_ctime)) {
263 (void)rd_skip(arcn->skip + arcn->pad);
267 if (arcn->sb.st_ctime <= sb.st_ctime) {
268 (void)rd_skip(arcn->skip + arcn->pad);
271 } else if (arcn->sb.st_mtime <= sb.st_mtime) {
272 (void)rd_skip(arcn->skip + arcn->pad);
279 ls_list(arcn, now, listf);
281 (void)fputs(arcn->name, listf);
287 * if required, chdir around.
289 if ((arcn->pat != NULL) && (arcn->pat->chdname != NULL))
290 if (chdir(arcn->pat->chdname) != 0)
291 syswarn(1, errno, "Cannot chdir to %s",
295 * all ok, extract this member based on type
297 if ((arcn->type != PAX_REG) && (arcn->type != PAX_CTG)) {
299 * process archive members that are not regular files.
300 * throw out padding and any data that might follow the
301 * header (as determined by the format).
303 if ((arcn->type == PAX_HLK) || (arcn->type == PAX_HRG))
304 res = lnk_creat(arcn);
306 res = node_creat(arcn);
308 (void)rd_skip(arcn->skip + arcn->pad);
312 if (vflag && vfpart) {
313 (void)putc('\n', listf);
319 * we have a file with data here. If we can not create it, skip
320 * over the data and purge the name from hard link table
322 if ((fd = file_creat(arcn)) < 0) {
323 (void)rd_skip(arcn->skip + arcn->pad);
328 * extract the file from the archive and skip over padding and
329 * any unprocessed data
331 res = (*frmt->rd_data)(arcn, fd, &cnt);
332 file_close(arcn, fd);
333 if (vflag && vfpart) {
334 (void)putc('\n', listf);
338 (void)rd_skip(cnt + arcn->pad);
341 * if required, chdir around.
343 if ((arcn->pat != NULL) && (arcn->pat->chdname != NULL))
344 if (fchdir(cwdfd) != 0)
346 "Can't fchdir to starting directory");
350 * all done, restore directory modes and times as required; make sure
351 * all patterns supplied by the user were matched; block off signals
352 * to avoid chance for multiple entry into the cleanup code.
354 (void)(*frmt->end_rd)();
355 (void)sigprocmask(SIG_BLOCK, &s_mask, NULL);
363 * Write an archive. used in both creating a new archive and appends on
364 * previously written archive.
369 wr_archive(register ARCHD *arcn, int is_app)
372 wr_archive(arcn, is_app)
373 register ARCHD *arcn;
386 * if this format supports hard link storage, start up the database
389 if (((hlk = frmt->hlk) == 1) && (lnk_start() < 0))
393 * start up the file traversal code and format specific write
395 if ((ftree_start() < 0) || ((*frmt->st_wr)() < 0))
400 * When we are doing interactive rename, we store the mapping of names
401 * so we can fix up hard links files later in the archive.
403 if (iflag && (name_start() < 0))
407 * if this not append, and there are no files, we do no write a trailer
414 * while there are files to archive, process them one at at time
416 while (next_file(arcn) == 0) {
418 * check if this file meets user specified options match.
420 if (sel_chk(arcn) != 0)
425 * only archive if this file is newer than a file with
426 * the same name that is already stored on the archive
428 if ((res = chk_ftime(arcn)) < 0)
435 * this file is considered selected now. see if this is a hard
436 * link to a file already stored
439 if (hlk && (chk_lnk(arcn) < 0))
442 if ((arcn->type == PAX_REG) || (arcn->type == PAX_HRG) ||
443 (arcn->type == PAX_CTG)) {
445 * we will have to read this file. by opening it now we
446 * can avoid writing a header to the archive for a file
447 * we were later unable to read (we also purge it from
450 if ((fd = open(arcn->org_name, O_RDONLY, 0)) < 0) {
451 syswarn(1,errno, "Unable to open %s to read",
459 * Now modify the name as requested by the user
461 if ((res = mod_name(arcn)) < 0) {
463 * name modification says to skip this file, close the
464 * file and purge link table entry
466 rdfile_close(arcn, &fd);
471 if ((res > 0) || (docrc && (set_crc(arcn, fd) < 0))) {
473 * unable to obtain the crc we need, close the file,
474 * purge link table entry
476 rdfile_close(arcn, &fd);
483 ls_list(arcn, now, listf);
485 (void)fputs(arcn->name, listf);
492 * looks safe to store the file, have the format specific
493 * routine write routine store the file header on the archive
495 if ((res = (*wrf)(arcn)) < 0) {
496 rdfile_close(arcn, &fd);
502 * format write says no file data needs to be stored
503 * so we are done messing with this file
505 if (vflag && vfpart) {
506 (void)putc('\n', listf);
509 rdfile_close(arcn, &fd);
514 * Add file data to the archive, quit on write error. if we
515 * cannot write the entire file contents to the archive we
516 * must pad the archive to replace the missing file data
517 * (otherwise during an extract the file header for the file
518 * which FOLLOWS this one will not be where we expect it to
521 res = (*frmt->wr_data)(arcn, fd, &cnt);
522 rdfile_close(arcn, &fd);
523 if (vflag && vfpart) {
524 (void)putc('\n', listf);
531 * pad as required, cnt is number of bytes not written
533 if (((cnt > 0) && (wr_skip(cnt) < 0)) ||
534 ((arcn->pad > 0) && (wr_skip(arcn->pad) < 0)))
539 * tell format to write trailer; pad to block boundary; reset directory
540 * mode/access times, and check if all patterns supplied by the user
541 * were matched. block off signals to avoid chance for multiple entry
542 * into the cleanup code
548 (void)sigprocmask(SIG_BLOCK, &s_mask, NULL);
557 * Add file to previously written archive. Archive format specified by the
558 * user must agree with archive. The archive is read first to collect
559 * modification times (if -u) and locate the archive trailer. The archive
560 * is positioned in front of the record with the trailer and wr_archive()
561 * is called to add the new members.
562 * PAX IMPLEMENTATION DETAIL NOTE:
563 * -u is implemented by adding the new members to the end of the archive.
564 * Care is taken so that these do not end up as links to the older
565 * version of the same file already stored in the archive. It is expected
566 * when extraction occurs these newer versions will over-write the older
567 * ones stored "earlier" in the archive (this may be a bad assumption as
568 * it depends on the implementation of the program doing the extraction).
569 * It is really difficult to splice in members without either re-writing
570 * the entire archive (from the point were the old version was), or having
571 * assistance of the format specification in terms of a special update
572 * header that invalidates a previous archive record. The POSIX spec left
573 * the method used to implement -u unspecified. This pax is able to
574 * over write existing files that it creates.
585 register ARCHD *arcn;
596 * Do not allow an append operation if the actual archive is of a
597 * different format than the user specified format.
601 if ((orgfrmt != NULL) && (orgfrmt != frmt)) {
602 paxwarn(1, "Cannot mix current archive format %s with %s",
603 frmt->name, orgfrmt->name);
608 * pass the format any options and start up format
610 if (((*frmt->options)() < 0) || ((*frmt->st_rd)() < 0))
614 * if we only are adding members that are newer, we need to save the
615 * mod times for all files we see.
617 if (uflag && (ftime_start() < 0))
621 * some archive formats encode hard links by recording the device and
622 * file serial number (inode) but copy the file anyway (multiple times)
623 * to the archive. When we append, we run the risk that newly added
624 * files may have the same device and inode numbers as those recorded
625 * on the archive but during a previous run. If this happens, when the
626 * archive is extracted we get INCORRECT hard links. We avoid this by
627 * remapping the device numbers so that newly added files will never
628 * use the same device number as one found on the archive. remapping
629 * allows new members to safely have links among themselves. remapping
630 * also avoids problems with file inode (serial number) truncations
631 * when the inode number is larger than storage space in the archive
632 * header. See the remap routines for more details.
634 if ((udev = frmt->udev) && (dev_start() < 0))
638 * reading the archive may take a long time. If verbose tell the user
642 "%s: Reading archive to position at the end...", argv0);
647 * step through the archive until the format says it is done
649 while (next_head(arcn) == 0) {
651 * check if this file meets user specified options.
653 if (sel_chk(arcn) != 0) {
654 if (rd_skip(arcn->skip + arcn->pad) == 1)
661 * see if this is the newest version of this file has
662 * already been seen, if so skip.
664 if ((res = chk_ftime(arcn)) < 0)
667 if (rd_skip(arcn->skip + arcn->pad) == 1)
674 * Store this device number. Device numbers seen during the
675 * read phase of append will cause newly appended files with a
676 * device number seen in the old part of the archive to be
677 * remapped to an unused device number.
679 if ((udev && (add_dev(arcn) < 0)) ||
680 (rd_skip(arcn->skip + arcn->pad) == 1))
685 * done, finish up read and get the number of bytes to back up so we
686 * can add new members. The format might have used the hard link table,
689 tlen = (*frmt->end_rd)();
693 * try to position for write, if this fails quit. if any error occurs,
694 * we will refuse to write
696 if (appnd_start(tlen) < 0)
700 * tell the user we are done reading.
702 if (vflag && vfpart) {
703 (void)fputs("done.\n", listf);
708 * go to the writing phase to add the new members
715 * write a new archive
729 * if we only are adding members that are newer, we need to save the
730 * mod times for all files; set up for writing; pass the format any
731 * options write the archive
733 if ((uflag && (ftime_start() < 0)) || (wr_start() < 0))
735 if ((*frmt->options)() < 0)
738 wr_archive(&archd, 0);
743 * copy files from one part of the file system to another. this does not
744 * use any archive storage. The EFFECT OF THE COPY IS THE SAME as if an
745 * archive was written and then extracted in the destination directory
746 * (except the files are forced to be under the destination directory).
757 register ARCHD *arcn;
760 register char *dest_pt;
766 char dirbuf[PAXPATHLEN+1];
770 * set up the destination dir path and make sure it is a directory. We
771 * make sure we have a trailing / on the destination
773 dlen = l_strncpy(dirbuf, dirptr, sizeof(dirbuf) - 1);
774 dest_pt = dirbuf + dlen;
775 if (*(dest_pt-1) != '/') {
780 drem = PAXPATHLEN - dlen;
782 if (stat(dirptr, &sb) < 0) {
783 syswarn(1, errno, "Cannot access destination directory %s",
787 if (!S_ISDIR(sb.st_mode)) {
788 paxwarn(1, "Destination is not a directory %s", dirptr);
793 * start up the hard link table; file traversal routines and the
794 * modification time and access mode database
796 if ((lnk_start() < 0) || (ftree_start() < 0) || (dir_start() < 0))
800 * When we are doing interactive rename, we store the mapping of names
801 * so we can fix up hard links files later in the archive.
803 if (iflag && (name_start() < 0))
807 * set up to cp file trees
812 * while there are files to archive, process them
814 while (next_file(arcn) == 0) {
818 * check if this file meets user specified options
820 if (sel_chk(arcn) != 0)
824 * if there is already a file in the destination directory with
825 * the same name and it is newer, skip the one stored on the
827 * NOTE: this test is done BEFORE name modifications as
828 * specified by pax. this can be confusing to the user who
829 * might expect the test to be done on an existing file AFTER
830 * the name mod. In honesty the pax spec is probably flawed in
833 if (uflag || Dflag) {
835 * create the destination name
837 if (*(arcn->name) == '/')
841 if ((arcn->nlen - res) > drem) {
842 paxwarn(1, "Destination pathname too long %s",
846 (void)strncpy(dest_pt, arcn->name + res, drem);
847 dirbuf[PAXPATHLEN] = '\0';
850 * if existing file is same age or newer skip
852 res = lstat(dirbuf, &sb);
856 if (uflag && Dflag) {
857 if ((arcn->sb.st_mtime<=sb.st_mtime) &&
858 (arcn->sb.st_ctime<=sb.st_ctime))
861 if (arcn->sb.st_ctime <= sb.st_ctime)
863 } else if (arcn->sb.st_mtime <= sb.st_mtime)
869 * this file is considered selected. See if this is a hard link
870 * to a previous file; modify the name as requested by the
871 * user; set the final destination.
874 if ((chk_lnk(arcn) < 0) || ((res = mod_name(arcn)) < 0))
876 if ((res > 0) || (set_dest(arcn, dirbuf, dlen) < 0)) {
878 * skip file, purge from link table
885 * Non standard -Y and -Z flag. When the exisiting file is
886 * same age or newer skip
888 if ((Yflag || Zflag) && ((lstat(arcn->name, &sb) == 0))) {
889 if (Yflag && Zflag) {
890 if ((arcn->sb.st_mtime <= sb.st_mtime) &&
891 (arcn->sb.st_ctime <= sb.st_ctime))
894 if (arcn->sb.st_ctime <= sb.st_ctime)
896 } else if (arcn->sb.st_mtime <= sb.st_mtime)
901 (void)fputs(arcn->name, listf);
907 * try to create a hard link to the src file if requested
908 * but make sure we are not trying to overwrite ourselves.
911 res = cross_lnk(arcn);
913 res = chk_same(arcn);
915 if (vflag && vfpart) {
916 (void)putc('\n', listf);
923 * have to create a new file
925 if ((arcn->type != PAX_REG) && (arcn->type != PAX_CTG)) {
927 * create a link or special file
929 if ((arcn->type == PAX_HLK) || (arcn->type == PAX_HRG))
930 res = lnk_creat(arcn);
932 res = node_creat(arcn);
935 if (vflag && vfpart) {
936 (void)putc('\n', listf);
943 * have to copy a regular file to the destination directory.
944 * first open source file and then create the destination file
946 if ((fdsrc = open(arcn->org_name, O_RDONLY, 0)) < 0) {
947 syswarn(1, errno, "Unable to open %s to read",
952 if ((fddest = file_creat(arcn)) < 0) {
953 rdfile_close(arcn, &fdsrc);
959 * copy source file data to the destination file
961 cp_file(arcn, fdsrc, fddest);
962 file_close(arcn, fddest);
963 rdfile_close(arcn, &fdsrc);
965 if (vflag && vfpart) {
966 (void)putc('\n', listf);
972 * restore directory modes and times as required; make sure all
973 * patterns were selected block off signals to avoid chance for
974 * multiple entry into the cleanup code.
976 (void)sigprocmask(SIG_BLOCK, &s_mask, NULL);
984 * try to find a valid header in the archive. Uses format specific
985 * routines to extract the header and id the trailer. Trailers may be
986 * located within a valid header or in an invalid header (the location
987 * is format specific. The inhead field from the option table tells us
988 * where to look for the trailer).
989 * We keep reading (and resyncing) until we get enough contiguous data
990 * to check for a header. If we cannot find one, we shift by a byte
991 * add a new byte from the archive to the end of the buffer and try again.
992 * If we get a read error, we throw out what we have (as we must have
993 * contiguous data) and start over again.
994 * ASSUMED: headers fit within a BLKMULT header.
996 * 0 if we got a header, -1 if we are unable to ever find another one
997 * (we reached the end of input, or we reached the limit on retries. see
998 * the specs for rd_wrbuf() for more details)
1003 next_head(register ARCHD *arcn)
1007 register ARCHD *arcn;
1011 register char *hdend;
1013 register int shftsz;
1015 register int in_resync = 0; /* set when we are in resync mode */
1016 int cnt = 0; /* counter for trailer function */
1017 int first = 1; /* on 1st read, EOF isn't premature. */
1020 * set up initial conditions, we want a whole frmt->hsz block as we
1023 res = hsz = frmt->hsz;
1028 * keep looping until we get a contiguous FULL buffer
1029 * (frmt->hsz is the proper size)
1032 if ((ret = rd_wrbuf(hdend, res)) == res)
1036 * If we read 0 bytes (EOF) from an archive when we
1037 * expect to find a header, we have stepped upon
1038 * an archive without the customary block of zeroes
1039 * end marker. It's just stupid to error out on
1040 * them, so exit gracefully.
1042 if (first && ret == 0)
1047 * some kind of archive read problem, try to resync the
1048 * storage device, better give the user the bad news.
1050 if ((ret == 0) || (rd_sync() < 0)) {
1051 paxwarn(1,"Premature end of file on archive read");
1057 "Archive I/O error, cannot continue");
1060 paxwarn(1,"Archive I/O error. Trying to recover.");
1065 * oh well, throw it all out and start over
1072 * ok we have a contiguous buffer of the right size. Call the
1073 * format read routine. If this was not a valid header and this
1074 * format stores trailers outside of the header, call the
1075 * format specific trailer routine to check for a trailer. We
1076 * have to watch out that we do not mis-identify file data or
1077 * block padding as a header or trailer. Format specific
1078 * trailer functions must NOT check for the trailer while we
1079 * are running in resync mode. Some trailer functions may tell
1080 * us that this block cannot contain a valid header either, so
1081 * we then throw out the entire block and start over.
1083 if ((*frmt->rd)(arcn, hdbuf) == 0)
1086 if (!frmt->inhead) {
1088 * this format has trailers outside of valid headers
1090 if ((ret = (*frmt->trail)(hdbuf,in_resync,&cnt)) == 0){
1092 * valid trailer found, drain input as required
1100 * we are in resync and we were told to throw
1101 * the whole block out because none of the
1102 * bytes in this block can be used to form a
1112 * Brute force section.
1113 * not a valid header. We may be able to find a header yet. So
1114 * we shift over by one byte, and set up to read one byte at a
1115 * time from the archive and place it at the end of the buffer.
1116 * We will keep moving byte at a time until we find a header or
1117 * get a read error and have to start over.
1121 paxwarn(1,"Unable to append, archive header flaw");
1124 paxwarn(1,"Invalid header, starting valid header search.");
1127 memmove(hdbuf, hdbuf+1, shftsz);
1129 hdend = hdbuf + shftsz;
1133 * ok got a valid header, check for trailer if format encodes it in the
1134 * the header. NOTE: the parameters are different than trailer routines
1135 * which encode trailers outside of the header!
1137 if (frmt->inhead && ((*frmt->trail)(arcn) == 0)) {
1139 * valid trailer found, drain input as required
1151 * Figure out what format an archive is. Handles archive with flaws by
1152 * brute force searches for a legal header in any supported format. The
1153 * format id routines have to be careful to NOT mis-identify a format.
1154 * ASSUMED: headers fit within a BLKMULT header.
1156 * 0 if archive found -1 otherwise
1168 register int hdsz = 0;
1170 register int minhd = BLKMULT;
1175 * find the smallest header size in all archive formats and then set up
1176 * to read the archive.
1178 for (i = 0; ford[i] >= 0; ++i) {
1179 if (fsub[ford[i]].hsz < minhd)
1180 minhd = fsub[ford[i]].hsz;
1190 * fill the buffer with at least the smallest header
1192 i = rd_wrbuf(hdend, res);
1199 * if we cannot recover from a read error quit
1201 if ((i == 0) || (rd_sync() < 0))
1205 * when we get an error none of the data we already
1206 * have can be used to create a legal header (we just
1207 * got an error in the middle), so we throw it all out
1208 * and refill the buffer with fresh data.
1216 paxwarn(1,"Cannot identify format. Searching...");
1222 * we have at least the size of the smallest header in any
1223 * archive format. Look to see if we have a match. The array
1224 * ford[] is used to specify the header id order to reduce the
1225 * chance of incorrectly id'ing a valid header (some formats
1226 * may be subsets of each other and the order would then be
1229 for (i = 0; ford[i] >= 0; ++i) {
1230 if ((*fsub[ford[i]].id)(hdbuf, hdsz) < 0)
1232 frmt = &(fsub[ford[i]]);
1234 * yuck, to avoid slow special case code in the extract
1235 * routines, just push this header back as if it was
1236 * not seen. We have left extra space at start of the
1237 * buffer for this purpose. This is a bit ugly, but
1238 * adding all the special case code is far worse.
1245 * We have a flawed archive, no match. we start searching, but
1246 * we never allow additions to flawed archives
1251 paxwarn(1, "Cannot identify format. Searching...");
1256 * brute force search for a header that we can id.
1257 * we shift through byte at a time. this is slow, but we cannot
1258 * determine the nature of the flaw in the archive in a
1262 memmove(hdbuf, hdbuf+1, hdsz);
1263 res = BLKMULT - hdsz;
1264 hdend = hdbuf + hdsz;
1274 * we cannot find a header, bow, apologize and quit
1276 paxwarn(1, "Sorry, unable to determine archive format.");