xref: /freebsd/bin/pax/ar_subs.c (revision 3c4ba5f55438f7afd4f4b0b56f88f2bb505fd6a6)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1992 Keith Muller.
5  * Copyright (c) 1992, 1993
6  *	The Regents of the University of California.  All rights reserved.
7  *
8  * This code is derived from software contributed to Berkeley by
9  * Keith Muller of the University of California, San Diego.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  * 3. 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.
22  *
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
33  * SUCH DAMAGE.
34  */
35 
36 #ifndef lint
37 #if 0
38 static char sccsid[] = "@(#)ar_subs.c	8.2 (Berkeley) 4/18/94";
39 #endif
40 #endif /* not lint */
41 #include <sys/cdefs.h>
42 __FBSDID("$FreeBSD$");
43 
44 #include <sys/types.h>
45 #include <sys/time.h>
46 #include <sys/stat.h>
47 #include <signal.h>
48 #include <string.h>
49 #include <stdio.h>
50 #include <fcntl.h>
51 #include <errno.h>
52 #include <unistd.h>
53 #include "pax.h"
54 #include "extern.h"
55 
56 static void wr_archive(ARCHD *, int is_app);
57 static int get_arc(void);
58 static int next_head(ARCHD *);
59 
60 /*
61  * Routines which control the overall operation modes of pax as specified by
62  * the user: list, append, read ...
63  */
64 
65 static char hdbuf[BLKMULT];		/* space for archive header on read */
66 u_long flcnt;				/* number of files processed */
67 
68 /*
69  * list()
70  *	list the contents of an archive which match user supplied pattern(s)
71  *	(no pattern matches all).
72  */
73 
74 void
75 list(void)
76 {
77 	ARCHD *arcn;
78 	int res;
79 	ARCHD archd;
80 	time_t now;
81 
82 	arcn = &archd;
83 	/*
84 	 * figure out archive type; pass any format specific options to the
85 	 * archive option processing routine; call the format init routine. We
86 	 * also save current time for ls_list() so we do not make a system
87 	 * call for each file we need to print. If verbose (vflag) start up
88 	 * the name and group caches.
89 	 */
90 	if ((get_arc() < 0) || ((*frmt->options)() < 0) ||
91 	    ((*frmt->st_rd)() < 0))
92 		return;
93 
94 	if (vflag && ((uidtb_start() < 0) || (gidtb_start() < 0)))
95 		return;
96 
97 	now = time(NULL);
98 
99 	/*
100 	 * step through the archive until the format says it is done
101 	 */
102 	while (next_head(arcn) == 0) {
103 		/*
104 		 * check for pattern, and user specified options match.
105 		 * When all patterns are matched we are done.
106 		 */
107 		if ((res = pat_match(arcn)) < 0)
108 			break;
109 
110 		if ((res == 0) && (sel_chk(arcn) == 0)) {
111 			/*
112 			 * pattern resulted in a selected file
113 			 */
114 			if (pat_sel(arcn) < 0)
115 				break;
116 
117 			/*
118 			 * modify the name as requested by the user if name
119 			 * survives modification, do a listing of the file
120 			 */
121 			if ((res = mod_name(arcn)) < 0)
122 				break;
123 			if (res == 0)
124 				ls_list(arcn, now, stdout);
125 		}
126 
127 		/*
128 		 * skip to next archive format header using values calculated
129 		 * by the format header read routine
130 		 */
131 		if (rd_skip(arcn->skip + arcn->pad) == 1)
132 			break;
133 	}
134 
135 	/*
136 	 * all done, let format have a chance to cleanup, and make sure that
137 	 * the patterns supplied by the user were all matched
138 	 */
139 	(void)(*frmt->end_rd)();
140 	(void)sigprocmask(SIG_BLOCK, &s_mask, NULL);
141 	ar_close();
142 	pat_chk();
143 }
144 
145 /*
146  * extract()
147  *	extract the member(s) of an archive as specified by user supplied
148  *	pattern(s) (no patterns extracts all members)
149  */
150 
151 void
152 extract(void)
153 {
154 	ARCHD *arcn;
155 	int res;
156 	off_t cnt;
157 	ARCHD archd;
158 	struct stat sb;
159 	int fd;
160 	time_t now;
161 
162 	arcn = &archd;
163 	/*
164 	 * figure out archive type; pass any format specific options to the
165 	 * archive option processing routine; call the format init routine;
166 	 * start up the directory modification time and access mode database
167 	 */
168 	if ((get_arc() < 0) || ((*frmt->options)() < 0) ||
169 	    ((*frmt->st_rd)() < 0) || (dir_start() < 0))
170 		return;
171 
172 	/*
173 	 * When we are doing interactive rename, we store the mapping of names
174 	 * so we can fix up hard links files later in the archive.
175 	 */
176 	if (iflag && (name_start() < 0))
177 		return;
178 
179 	now = time(NULL);
180 
181 	/*
182 	 * step through each entry on the archive until the format read routine
183 	 * says it is done
184 	 */
185 	while (next_head(arcn) == 0) {
186 
187 		/*
188 		 * check for pattern, and user specified options match. When
189 		 * all the patterns are matched we are done
190 		 */
191 		if ((res = pat_match(arcn)) < 0)
192 			break;
193 
194 		if ((res > 0) || (sel_chk(arcn) != 0)) {
195 			/*
196 			 * file is not selected. skip past any file data and
197 			 * padding and go back for the next archive member
198 			 */
199 			(void)rd_skip(arcn->skip + arcn->pad);
200 			continue;
201 		}
202 
203 		/*
204 		 * with -u or -D only extract when the archive member is newer
205 		 * than the file with the same name in the file system (no
206 		 * test of being the same type is required).
207 		 * NOTE: this test is done BEFORE name modifications as
208 		 * specified by pax. this operation can be confusing to the
209 		 * user who might expect the test to be done on an existing
210 		 * file AFTER the name mod. In honesty the pax spec is probably
211 		 * flawed in this respect.
212 		 */
213 		if ((uflag || Dflag) && ((lstat(arcn->name, &sb) == 0))) {
214 			if (uflag && Dflag) {
215 				if ((arcn->sb.st_mtime <= sb.st_mtime) &&
216 				    (arcn->sb.st_ctime <= sb.st_ctime)) {
217 					(void)rd_skip(arcn->skip + arcn->pad);
218 					continue;
219 				}
220 			} else if (Dflag) {
221 				if (arcn->sb.st_ctime <= sb.st_ctime) {
222 					(void)rd_skip(arcn->skip + arcn->pad);
223 					continue;
224 				}
225 			} else if (arcn->sb.st_mtime <= sb.st_mtime) {
226 				(void)rd_skip(arcn->skip + arcn->pad);
227 				continue;
228 			}
229 		}
230 
231 		/*
232 		 * this archive member is now been selected. modify the name.
233 		 */
234 		if ((pat_sel(arcn) < 0) || ((res = mod_name(arcn)) < 0))
235 			break;
236 		if (res > 0) {
237 			/*
238 			 * a bad name mod, skip and purge name from link table
239 			 */
240 			purg_lnk(arcn);
241 			(void)rd_skip(arcn->skip + arcn->pad);
242 			continue;
243 		}
244 
245 		/*
246 		 * Non standard -Y and -Z flag. When the existing file is
247 		 * same age or newer skip
248 		 */
249 		if ((Yflag || Zflag) && ((lstat(arcn->name, &sb) == 0))) {
250 			if (Yflag && Zflag) {
251 				if ((arcn->sb.st_mtime <= sb.st_mtime) &&
252 				    (arcn->sb.st_ctime <= sb.st_ctime)) {
253 					(void)rd_skip(arcn->skip + arcn->pad);
254 					continue;
255 				}
256 			} else if (Yflag) {
257 				if (arcn->sb.st_ctime <= sb.st_ctime) {
258 					(void)rd_skip(arcn->skip + arcn->pad);
259 					continue;
260 				}
261 			} else if (arcn->sb.st_mtime <= sb.st_mtime) {
262 				(void)rd_skip(arcn->skip + arcn->pad);
263 				continue;
264 			}
265 		}
266 
267 		if (vflag) {
268 			if (vflag > 1)
269 				ls_list(arcn, now, listf);
270 			else {
271 				(void)fputs(arcn->name, listf);
272 				vfpart = 1;
273 			}
274 		}
275 
276 		/*
277 		 * if required, chdir around.
278 		 */
279 		if ((arcn->pat != NULL) && (arcn->pat->chdname != NULL))
280 			if (chdir(arcn->pat->chdname) != 0)
281 				syswarn(1, errno, "Cannot chdir to %s",
282 				    arcn->pat->chdname);
283 
284 		/*
285 		 * all ok, extract this member based on type
286 		 */
287 		if ((arcn->type != PAX_REG) && (arcn->type != PAX_CTG)) {
288 			/*
289 			 * process archive members that are not regular files.
290 			 * throw out padding and any data that might follow the
291 			 * header (as determined by the format).
292 			 */
293 			if ((arcn->type == PAX_HLK) || (arcn->type == PAX_HRG))
294 				res = lnk_creat(arcn);
295 			else
296 				res = node_creat(arcn);
297 
298 			(void)rd_skip(arcn->skip + arcn->pad);
299 			if (res < 0)
300 				purg_lnk(arcn);
301 
302 			if (vflag && vfpart) {
303 				(void)putc('\n', listf);
304 				vfpart = 0;
305 			}
306 			continue;
307 		}
308 		/*
309 		 * we have a file with data here. If we can not create it, skip
310 		 * over the data and purge the name from hard link table
311 		 */
312 		if ((fd = file_creat(arcn)) < 0) {
313 			(void)rd_skip(arcn->skip + arcn->pad);
314 			purg_lnk(arcn);
315 			continue;
316 		}
317 		/*
318 		 * extract the file from the archive and skip over padding and
319 		 * any unprocessed data
320 		 */
321 		res = (*frmt->rd_data)(arcn, fd, &cnt);
322 		file_close(arcn, fd);
323 		if (vflag && vfpart) {
324 			(void)putc('\n', listf);
325 			vfpart = 0;
326 		}
327 		if (!res)
328 			(void)rd_skip(cnt + arcn->pad);
329 
330 		/*
331 		 * if required, chdir around.
332 		 */
333 		if ((arcn->pat != NULL) && (arcn->pat->chdname != NULL))
334 			if (fchdir(cwdfd) != 0)
335 				syswarn(1, errno,
336 				    "Can't fchdir to starting directory");
337 	}
338 
339 	/*
340 	 * all done, restore directory modes and times as required; make sure
341 	 * all patterns supplied by the user were matched; block off signals
342 	 * to avoid chance for multiple entry into the cleanup code.
343 	 */
344 	(void)(*frmt->end_rd)();
345 	(void)sigprocmask(SIG_BLOCK, &s_mask, NULL);
346 	ar_close();
347 	proc_dir();
348 	pat_chk();
349 }
350 
351 /*
352  * wr_archive()
353  *	Write an archive. used in both creating a new archive and appends on
354  *	previously written archive.
355  */
356 
357 static void
358 wr_archive(ARCHD *arcn, int is_app)
359 {
360 	int res;
361 	int hlk;
362 	int wr_one;
363 	off_t cnt;
364 	int (*wrf)(ARCHD *);
365 	int fd = -1;
366 	time_t now;
367 
368 	/*
369 	 * if this format supports hard link storage, start up the database
370 	 * that detects them.
371 	 */
372 	if (((hlk = frmt->hlk) == 1) && (lnk_start() < 0))
373 		return;
374 
375 	/*
376 	 * start up the file traversal code and format specific write
377 	 */
378 	if ((ftree_start() < 0) || ((*frmt->st_wr)() < 0))
379 		return;
380 	wrf = frmt->wr;
381 
382 	/*
383 	 * When we are doing interactive rename, we store the mapping of names
384 	 * so we can fix up hard links files later in the archive.
385 	 */
386 	if (iflag && (name_start() < 0))
387 		return;
388 
389 	/*
390 	 * if this is not append, and there are no files, we do not write a
391 	 * trailer
392 	 */
393 	wr_one = is_app;
394 
395 	now = time(NULL);
396 
397 	/*
398 	 * while there are files to archive, process them one at at time
399 	 */
400 	while (next_file(arcn) == 0) {
401 		/*
402 		 * check if this file meets user specified options match.
403 		 */
404 		if (sel_chk(arcn) != 0) {
405 			ftree_notsel();
406 			continue;
407 		}
408 		fd = -1;
409 		if (uflag) {
410 			/*
411 			 * only archive if this file is newer than a file with
412 			 * the same name that is already stored on the archive
413 			 */
414 			if ((res = chk_ftime(arcn)) < 0)
415 				break;
416 			if (res > 0)
417 				continue;
418 		}
419 
420 		/*
421 		 * this file is considered selected now. see if this is a hard
422 		 * link to a file already stored
423 		 */
424 		ftree_sel(arcn);
425 		if (hlk && (chk_lnk(arcn) < 0))
426 			break;
427 
428 		if ((arcn->type == PAX_REG) || (arcn->type == PAX_HRG) ||
429 		    (arcn->type == PAX_CTG)) {
430 			/*
431 			 * we will have to read this file. by opening it now we
432 			 * can avoid writing a header to the archive for a file
433 			 * we were later unable to read (we also purge it from
434 			 * the link table).
435 			 */
436 			if ((fd = open(arcn->org_name, O_RDONLY, 0)) < 0) {
437 				syswarn(1,errno, "Unable to open %s to read",
438 					arcn->org_name);
439 				purg_lnk(arcn);
440 				continue;
441 			}
442 		}
443 
444 		/*
445 		 * Now modify the name as requested by the user
446 		 */
447 		if ((res = mod_name(arcn)) < 0) {
448 			/*
449 			 * name modification says to skip this file, close the
450 			 * file and purge link table entry
451 			 */
452 			rdfile_close(arcn, &fd);
453 			purg_lnk(arcn);
454 			break;
455 		}
456 
457 		if ((res > 0) || (docrc && (set_crc(arcn, fd) < 0))) {
458 			/*
459 			 * unable to obtain the crc we need, close the file,
460 			 * purge link table entry
461 			 */
462 			rdfile_close(arcn, &fd);
463 			purg_lnk(arcn);
464 			continue;
465 		}
466 
467 		if (vflag) {
468 			if (vflag > 1)
469 				ls_list(arcn, now, listf);
470 			else {
471 				(void)fputs(arcn->name, listf);
472 				vfpart = 1;
473 			}
474 		}
475 		++flcnt;
476 
477 		/*
478 		 * looks safe to store the file, have the format specific
479 		 * routine write routine store the file header on the archive
480 		 */
481 		if ((res = (*wrf)(arcn)) < 0) {
482 			rdfile_close(arcn, &fd);
483 			break;
484 		}
485 		wr_one = 1;
486 		if (res > 0) {
487 			/*
488 			 * format write says no file data needs to be stored
489 			 * so we are done messing with this file
490 			 */
491 			if (vflag && vfpart) {
492 				(void)putc('\n', listf);
493 				vfpart = 0;
494 			}
495 			rdfile_close(arcn, &fd);
496 			continue;
497 		}
498 
499 		/*
500 		 * Add file data to the archive, quit on write error. if we
501 		 * cannot write the entire file contents to the archive we
502 		 * must pad the archive to replace the missing file data
503 		 * (otherwise during an extract the file header for the file
504 		 * which FOLLOWS this one will not be where we expect it to
505 		 * be).
506 		 */
507 		res = (*frmt->wr_data)(arcn, fd, &cnt);
508 		rdfile_close(arcn, &fd);
509 		if (vflag && vfpart) {
510 			(void)putc('\n', listf);
511 			vfpart = 0;
512 		}
513 		if (res < 0)
514 			break;
515 
516 		/*
517 		 * pad as required, cnt is number of bytes not written
518 		 */
519 		if (((cnt > 0) && (wr_skip(cnt) < 0)) ||
520 		    ((arcn->pad > 0) && (wr_skip(arcn->pad) < 0)))
521 			break;
522 	}
523 
524 	/*
525 	 * tell format to write trailer; pad to block boundary; reset directory
526 	 * mode/access times, and check if all patterns supplied by the user
527 	 * were matched. block off signals to avoid chance for multiple entry
528 	 * into the cleanup code
529 	 */
530 	if (wr_one) {
531 		(*frmt->end_wr)();
532 		wr_fin();
533 	}
534 	(void)sigprocmask(SIG_BLOCK, &s_mask, NULL);
535 	ar_close();
536 	if (tflag)
537 		proc_dir();
538 	ftree_chk();
539 }
540 
541 /*
542  * append()
543  *	Add file to previously written archive. Archive format specified by the
544  *	user must agree with archive. The archive is read first to collect
545  *	modification times (if -u) and locate the archive trailer. The archive
546  *	is positioned in front of the record with the trailer and wr_archive()
547  *	is called to add the new members.
548  *	PAX IMPLEMENTATION DETAIL NOTE:
549  *	-u is implemented by adding the new members to the end of the archive.
550  *	Care is taken so that these do not end up as links to the older
551  *	version of the same file already stored in the archive. It is expected
552  *	when extraction occurs these newer versions will over-write the older
553  *	ones stored "earlier" in the archive (this may be a bad assumption as
554  *	it depends on the implementation of the program doing the extraction).
555  *	It is really difficult to splice in members without either re-writing
556  *	the entire archive (from the point were the old version was), or having
557  *	assistance of the format specification in terms of a special update
558  *	header that invalidates a previous archive record. The POSIX spec left
559  *	the method used to implement -u unspecified. This pax is able to
560  *	over write existing files that it creates.
561  */
562 
563 void
564 append(void)
565 {
566 	ARCHD *arcn;
567 	int res;
568 	ARCHD archd;
569 	FSUB *orgfrmt;
570 	int udev;
571 	off_t tlen;
572 
573 	arcn = &archd;
574 	orgfrmt = frmt;
575 
576 	/*
577 	 * Do not allow an append operation if the actual archive is of a
578 	 * different format than the user specified format.
579 	 */
580 	if (get_arc() < 0)
581 		return;
582 	if ((orgfrmt != NULL) && (orgfrmt != frmt)) {
583 		paxwarn(1, "Cannot mix current archive format %s with %s",
584 		    frmt->name, orgfrmt->name);
585 		return;
586 	}
587 
588 	/*
589 	 * pass the format any options and start up format
590 	 */
591 	if (((*frmt->options)() < 0) || ((*frmt->st_rd)() < 0))
592 		return;
593 
594 	/*
595 	 * if we only are adding members that are newer, we need to save the
596 	 * mod times for all files we see.
597 	 */
598 	if (uflag && (ftime_start() < 0))
599 		return;
600 
601 	/*
602 	 * some archive formats encode hard links by recording the device and
603 	 * file serial number (inode) but copy the file anyway (multiple times)
604 	 * to the archive. When we append, we run the risk that newly added
605 	 * files may have the same device and inode numbers as those recorded
606 	 * on the archive but during a previous run. If this happens, when the
607 	 * archive is extracted we get INCORRECT hard links. We avoid this by
608 	 * remapping the device numbers so that newly added files will never
609 	 * use the same device number as one found on the archive. remapping
610 	 * allows new members to safely have links among themselves. remapping
611 	 * also avoids problems with file inode (serial number) truncations
612 	 * when the inode number is larger than storage space in the archive
613 	 * header. See the remap routines for more details.
614 	 */
615 	if ((udev = frmt->udev) && (dev_start() < 0))
616 		return;
617 
618 	/*
619 	 * reading the archive may take a long time. If verbose tell the user
620 	 */
621 	if (vflag) {
622 		(void)fprintf(listf,
623 			"%s: Reading archive to position at the end...", argv0);
624 		vfpart = 1;
625 	}
626 
627 	/*
628 	 * step through the archive until the format says it is done
629 	 */
630 	while (next_head(arcn) == 0) {
631 		/*
632 		 * check if this file meets user specified options.
633 		 */
634 		if (sel_chk(arcn) != 0) {
635 			if (rd_skip(arcn->skip + arcn->pad) == 1)
636 				break;
637 			continue;
638 		}
639 
640 		if (uflag) {
641 			/*
642 			 * see if this is the newest version of this file has
643 			 * already been seen, if so skip.
644 			 */
645 			if ((res = chk_ftime(arcn)) < 0)
646 				break;
647 			if (res > 0) {
648 				if (rd_skip(arcn->skip + arcn->pad) == 1)
649 					break;
650 				continue;
651 			}
652 		}
653 
654 		/*
655 		 * Store this device number. Device numbers seen during the
656 		 * read phase of append will cause newly appended files with a
657 		 * device number seen in the old part of the archive to be
658 		 * remapped to an unused device number.
659 		 */
660 		if ((udev && (add_dev(arcn) < 0)) ||
661 		    (rd_skip(arcn->skip + arcn->pad) == 1))
662 			break;
663 	}
664 
665 	/*
666 	 * done, finish up read and get the number of bytes to back up so we
667 	 * can add new members. The format might have used the hard link table,
668 	 * purge it.
669 	 */
670 	tlen = (*frmt->end_rd)();
671 	lnk_end();
672 
673 	/*
674 	 * try to position for write, if this fails quit. if any error occurs,
675 	 * we will refuse to write
676 	 */
677 	if (appnd_start(tlen) < 0)
678 		return;
679 
680 	/*
681 	 * tell the user we are done reading.
682 	 */
683 	if (vflag && vfpart) {
684 		(void)fputs("done.\n", listf);
685 		vfpart = 0;
686 	}
687 
688 	/*
689 	 * go to the writing phase to add the new members
690 	 */
691 	wr_archive(arcn, 1);
692 }
693 
694 /*
695  * archive()
696  *	write a new archive
697  */
698 
699 void
700 archive(void)
701 {
702 	ARCHD archd;
703 
704 	/*
705 	 * if we only are adding members that are newer, we need to save the
706 	 * mod times for all files; set up for writing; pass the format any
707 	 * options write the archive
708 	 */
709 	if ((uflag && (ftime_start() < 0)) || (wr_start() < 0))
710 		return;
711 	if ((*frmt->options)() < 0)
712 		return;
713 
714 	wr_archive(&archd, 0);
715 }
716 
717 /*
718  * copy()
719  *	copy files from one part of the file system to another. this does not
720  *	use any archive storage. The EFFECT OF THE COPY IS THE SAME as if an
721  *	archive was written and then extracted in the destination directory
722  *	(except the files are forced to be under the destination directory).
723  */
724 
725 void
726 copy(void)
727 {
728 	ARCHD *arcn;
729 	int res;
730 	int fddest;
731 	char *dest_pt;
732 	int dlen;
733 	int drem;
734 	int fdsrc = -1;
735 	struct stat sb;
736 	ARCHD archd;
737 	char dirbuf[PAXPATHLEN+1];
738 
739 	arcn = &archd;
740 	/*
741 	 * set up the destination dir path and make sure it is a directory. We
742 	 * make sure we have a trailing / on the destination
743 	 */
744 	dlen = l_strncpy(dirbuf, dirptr, sizeof(dirbuf) - 1);
745 	dest_pt = dirbuf + dlen;
746 	if (*(dest_pt-1) != '/') {
747 		*dest_pt++ = '/';
748 		++dlen;
749 	}
750 	*dest_pt = '\0';
751 	drem = PAXPATHLEN - dlen;
752 
753 	if (stat(dirptr, &sb) < 0) {
754 		syswarn(1, errno, "Cannot access destination directory %s",
755 			dirptr);
756 		return;
757 	}
758 	if (!S_ISDIR(sb.st_mode)) {
759 		paxwarn(1, "Destination is not a directory %s", dirptr);
760 		return;
761 	}
762 
763 	/*
764 	 * start up the hard link table; file traversal routines and the
765 	 * modification time and access mode database
766 	 */
767 	if ((lnk_start() < 0) || (ftree_start() < 0) || (dir_start() < 0))
768 		return;
769 
770 	/*
771 	 * When we are doing interactive rename, we store the mapping of names
772 	 * so we can fix up hard links files later in the archive.
773 	 */
774 	if (iflag && (name_start() < 0))
775 		return;
776 
777 	/*
778 	 * set up to cp file trees
779 	 */
780 	cp_start();
781 
782 	/*
783 	 * while there are files to archive, process them
784 	 */
785 	while (next_file(arcn) == 0) {
786 		fdsrc = -1;
787 
788 		/*
789 		 * check if this file meets user specified options
790 		 */
791 		if (sel_chk(arcn) != 0) {
792 			ftree_notsel();
793 			continue;
794 		}
795 
796 		/*
797 		 * if there is already a file in the destination directory with
798 		 * the same name and it is newer, skip the one stored on the
799 		 * archive.
800 		 * NOTE: this test is done BEFORE name modifications as
801 		 * specified by pax. this can be confusing to the user who
802 		 * might expect the test to be done on an existing file AFTER
803 		 * the name mod. In honesty the pax spec is probably flawed in
804 		 * this respect
805 		 */
806 		if (uflag || Dflag) {
807 			/*
808 			 * create the destination name
809 			 */
810 			if (*(arcn->name) == '/')
811 				res = 1;
812 			else
813 				res = 0;
814 			if ((arcn->nlen - res) > drem) {
815 				paxwarn(1, "Destination pathname too long %s",
816 					arcn->name);
817 				continue;
818 			}
819 			(void)strncpy(dest_pt, arcn->name + res, drem);
820 			dirbuf[PAXPATHLEN] = '\0';
821 
822 			/*
823 			 * if existing file is same age or newer skip
824 			 */
825 			res = lstat(dirbuf, &sb);
826 			*dest_pt = '\0';
827 
828 		    	if (res == 0) {
829 				if (uflag && Dflag) {
830 					if ((arcn->sb.st_mtime<=sb.st_mtime) &&
831 			    		    (arcn->sb.st_ctime<=sb.st_ctime))
832 						continue;
833 				} else if (Dflag) {
834 					if (arcn->sb.st_ctime <= sb.st_ctime)
835 						continue;
836 				} else if (arcn->sb.st_mtime <= sb.st_mtime)
837 					continue;
838 			}
839 		}
840 
841 		/*
842 		 * this file is considered selected. See if this is a hard link
843 		 * to a previous file; modify the name as requested by the
844 		 * user; set the final destination.
845 		 */
846 		ftree_sel(arcn);
847 		if ((chk_lnk(arcn) < 0) || ((res = mod_name(arcn)) < 0))
848 			break;
849 		if ((res > 0) || (set_dest(arcn, dirbuf, dlen) < 0)) {
850 			/*
851 			 * skip file, purge from link table
852 			 */
853 			purg_lnk(arcn);
854 			continue;
855 		}
856 
857 		/*
858 		 * Non standard -Y and -Z flag. When the existing file is
859 		 * same age or newer skip
860 		 */
861 		if ((Yflag || Zflag) && ((lstat(arcn->name, &sb) == 0))) {
862 			if (Yflag && Zflag) {
863 				if ((arcn->sb.st_mtime <= sb.st_mtime) &&
864 				    (arcn->sb.st_ctime <= sb.st_ctime))
865 					continue;
866 			} else if (Yflag) {
867 				if (arcn->sb.st_ctime <= sb.st_ctime)
868 					continue;
869 			} else if (arcn->sb.st_mtime <= sb.st_mtime)
870 				continue;
871 		}
872 
873 		if (vflag) {
874 			(void)fputs(arcn->name, listf);
875 			vfpart = 1;
876 		}
877 		++flcnt;
878 
879 		/*
880 		 * try to create a hard link to the src file if requested
881 		 * but make sure we are not trying to overwrite ourselves.
882 		 */
883 		if (lflag)
884 			res = cross_lnk(arcn);
885 		else
886 			res = chk_same(arcn);
887 		if (res <= 0) {
888 			if (vflag && vfpart) {
889 				(void)putc('\n', listf);
890 				vfpart = 0;
891 			}
892 			continue;
893 		}
894 
895 		/*
896 		 * have to create a new file
897 		 */
898 		if ((arcn->type != PAX_REG) && (arcn->type != PAX_CTG)) {
899 			/*
900 			 * create a link or special file
901 			 */
902 			if ((arcn->type == PAX_HLK) || (arcn->type == PAX_HRG))
903 				res = lnk_creat(arcn);
904 			else
905 				res = node_creat(arcn);
906 			if (res < 0)
907 				purg_lnk(arcn);
908 			if (vflag && vfpart) {
909 				(void)putc('\n', listf);
910 				vfpart = 0;
911 			}
912 			continue;
913 		}
914 
915 		/*
916 		 * have to copy a regular file to the destination directory.
917 		 * first open source file and then create the destination file
918 		 */
919 		if ((fdsrc = open(arcn->org_name, O_RDONLY, 0)) < 0) {
920 			syswarn(1, errno, "Unable to open %s to read",
921 			    arcn->org_name);
922 			purg_lnk(arcn);
923 			continue;
924 		}
925 		if ((fddest = file_creat(arcn)) < 0) {
926 			rdfile_close(arcn, &fdsrc);
927 			purg_lnk(arcn);
928 			continue;
929 		}
930 
931 		/*
932 		 * copy source file data to the destination file
933 		 */
934 		cp_file(arcn, fdsrc, fddest);
935 		file_close(arcn, fddest);
936 		rdfile_close(arcn, &fdsrc);
937 
938 		if (vflag && vfpart) {
939 			(void)putc('\n', listf);
940 			vfpart = 0;
941 		}
942 	}
943 
944 	/*
945 	 * restore directory modes and times as required; make sure all
946 	 * patterns were selected block off signals to avoid chance for
947 	 * multiple entry into the cleanup code.
948 	 */
949 	(void)sigprocmask(SIG_BLOCK, &s_mask, NULL);
950 	ar_close();
951 	proc_dir();
952 	ftree_chk();
953 }
954 
955 /*
956  * next_head()
957  *	try to find a valid header in the archive. Uses format specific
958  *	routines to extract the header and id the trailer. Trailers may be
959  *	located within a valid header or in an invalid header (the location
960  *	is format specific. The inhead field from the option table tells us
961  *	where to look for the trailer).
962  *	We keep reading (and resyncing) until we get enough contiguous data
963  *	to check for a header. If we cannot find one, we shift by a byte
964  *	add a new byte from the archive to the end of the buffer and try again.
965  *	If we get a read error, we throw out what we have (as we must have
966  *	contiguous data) and start over again.
967  *	ASSUMED: headers fit within a BLKMULT header.
968  * Return:
969  *	0 if we got a header, -1 if we are unable to ever find another one
970  *	(we reached the end of input, or we reached the limit on retries. see
971  *	the specs for rd_wrbuf() for more details)
972  */
973 
974 static int
975 next_head(ARCHD *arcn)
976 {
977 	int ret;
978 	char *hdend;
979 	int res;
980 	int shftsz;
981 	int hsz;
982 	int in_resync = 0; 	/* set when we are in resync mode */
983 	int cnt = 0;			/* counter for trailer function */
984 	int first = 1;			/* on 1st read, EOF isn't premature. */
985 
986 	/*
987 	 * set up initial conditions, we want a whole frmt->hsz block as we
988 	 * have no data yet.
989 	 */
990 	res = hsz = frmt->hsz;
991 	hdend = hdbuf;
992 	shftsz = hsz - 1;
993 	for(;;) {
994 		/*
995 		 * keep looping until we get a contiguous FULL buffer
996 		 * (frmt->hsz is the proper size)
997 		 */
998 		for (;;) {
999 			if ((ret = rd_wrbuf(hdend, res)) == res)
1000 				break;
1001 
1002 			/*
1003 			 * If we read 0 bytes (EOF) from an archive when we
1004 			 * expect to find a header, we have stepped upon
1005 			 * an archive without the customary block of zeroes
1006 			 * end marker.  It's just stupid to error out on
1007 			 * them, so exit gracefully.
1008 			 */
1009 			if (first && ret == 0)
1010 				return(-1);
1011 			first = 0;
1012 
1013 			/*
1014 			 * some kind of archive read problem, try to resync the
1015 			 * storage device, better give the user the bad news.
1016 			 */
1017 			if ((ret == 0) || (rd_sync() < 0)) {
1018 				paxwarn(1,"Premature end of file on archive read");
1019 				return(-1);
1020 			}
1021 			if (!in_resync) {
1022 				if (act == APPND) {
1023 					paxwarn(1,
1024 					  "Archive I/O error, cannot continue");
1025 					return(-1);
1026 				}
1027 				paxwarn(1,"Archive I/O error. Trying to recover.");
1028 				++in_resync;
1029 			}
1030 
1031 			/*
1032 			 * oh well, throw it all out and start over
1033 			 */
1034 			res = hsz;
1035 			hdend = hdbuf;
1036 		}
1037 
1038 		/*
1039 		 * ok we have a contiguous buffer of the right size. Call the
1040 		 * format read routine. If this was not a valid header and this
1041 		 * format stores trailers outside of the header, call the
1042 		 * format specific trailer routine to check for a trailer. We
1043 		 * have to watch out that we do not mis-identify file data or
1044 		 * block padding as a header or trailer. Format specific
1045 		 * trailer functions must NOT check for the trailer while we
1046 		 * are running in resync mode. Some trailer functions may tell
1047 		 * us that this block cannot contain a valid header either, so
1048 		 * we then throw out the entire block and start over.
1049 		 */
1050 		if ((*frmt->rd)(arcn, hdbuf) == 0)
1051 			break;
1052 
1053 		if (!frmt->inhead) {
1054 			/*
1055 			 * this format has trailers outside of valid headers
1056 			 */
1057 			if ((ret = (*frmt->trail_tar)(hdbuf,in_resync,&cnt)) == 0){
1058 				/*
1059 				 * valid trailer found, drain input as required
1060 				 */
1061 				ar_drain();
1062 				return(-1);
1063 			}
1064 
1065 			if (ret == 1) {
1066 				/*
1067 				 * we are in resync and we were told to throw
1068 				 * the whole block out because none of the
1069 				 * bytes in this block can be used to form a
1070 				 * valid header
1071 				 */
1072 				res = hsz;
1073 				hdend = hdbuf;
1074 				continue;
1075 			}
1076 		}
1077 
1078 		/*
1079 		 * Brute force section.
1080 		 * not a valid header. We may be able to find a header yet. So
1081 		 * we shift over by one byte, and set up to read one byte at a
1082 		 * time from the archive and place it at the end of the buffer.
1083 		 * We will keep moving byte at a time until we find a header or
1084 		 * get a read error and have to start over.
1085 		 */
1086 		if (!in_resync) {
1087 			if (act == APPND) {
1088 				paxwarn(1,"Unable to append, archive header flaw");
1089 				return(-1);
1090 			}
1091 			paxwarn(1,"Invalid header, starting valid header search.");
1092 			++in_resync;
1093 		}
1094 		memmove(hdbuf, hdbuf+1, shftsz);
1095 		res = 1;
1096 		hdend = hdbuf + shftsz;
1097 	}
1098 
1099 	/*
1100 	 * ok got a valid header, check for trailer if format encodes it in
1101 	 * the header.
1102 	 */
1103 	if (frmt->inhead && ((*frmt->trail_cpio)(arcn) == 0)) {
1104 		/*
1105 		 * valid trailer found, drain input as required
1106 		 */
1107 		ar_drain();
1108 		return(-1);
1109 	}
1110 
1111 	++flcnt;
1112 	return(0);
1113 }
1114 
1115 /*
1116  * get_arc()
1117  *	Figure out what format an archive is. Handles archive with flaws by
1118  *	brute force searches for a legal header in any supported format. The
1119  *	format id routines have to be careful to NOT mis-identify a format.
1120  *	ASSUMED: headers fit within a BLKMULT header.
1121  * Return:
1122  *	0 if archive found -1 otherwise
1123  */
1124 
1125 static int
1126 get_arc(void)
1127 {
1128 	int i;
1129 	int hdsz = 0;
1130 	int res;
1131 	int minhd = BLKMULT;
1132 	char *hdend;
1133 	int notice = 0;
1134 
1135 	/*
1136 	 * find the smallest header size in all archive formats and then set up
1137 	 * to read the archive.
1138 	 */
1139 	for (i = 0; ford[i] >= 0; ++i) {
1140 		if (fsub[ford[i]].hsz < minhd)
1141 			minhd = fsub[ford[i]].hsz;
1142 	}
1143 	if (rd_start() < 0)
1144 		return(-1);
1145 	res = BLKMULT;
1146 	hdsz = 0;
1147 	hdend = hdbuf;
1148 	for(;;) {
1149 		for (;;) {
1150 			/*
1151 			 * fill the buffer with at least the smallest header
1152 			 */
1153 			i = rd_wrbuf(hdend, res);
1154 			if (i > 0)
1155 				hdsz += i;
1156 			if (hdsz >= minhd)
1157 				break;
1158 
1159 			/*
1160 			 * if we cannot recover from a read error quit
1161 			 */
1162 			if ((i == 0) || (rd_sync() < 0))
1163 				goto out;
1164 
1165 			/*
1166 			 * when we get an error none of the data we already
1167 			 * have can be used to create a legal header (we just
1168 			 * got an error in the middle), so we throw it all out
1169 			 * and refill the buffer with fresh data.
1170 			 */
1171 			res = BLKMULT;
1172 			hdsz = 0;
1173 			hdend = hdbuf;
1174 			if (!notice) {
1175 				if (act == APPND)
1176 					return(-1);
1177 				paxwarn(1,"Cannot identify format. Searching...");
1178 				++notice;
1179 			}
1180 		}
1181 
1182 		/*
1183 		 * we have at least the size of the smallest header in any
1184 		 * archive format. Look to see if we have a match. The array
1185 		 * ford[] is used to specify the header id order to reduce the
1186 		 * chance of incorrectly id'ing a valid header (some formats
1187 		 * may be subsets of each other and the order would then be
1188 		 * important).
1189 		 */
1190 		for (i = 0; ford[i] >= 0; ++i) {
1191 			if ((*fsub[ford[i]].id)(hdbuf, hdsz) < 0)
1192 				continue;
1193 			frmt = &(fsub[ford[i]]);
1194 			/*
1195 			 * yuck, to avoid slow special case code in the extract
1196 			 * routines, just push this header back as if it was
1197 			 * not seen. We have left extra space at start of the
1198 			 * buffer for this purpose. This is a bit ugly, but
1199 			 * adding all the special case code is far worse.
1200 			 */
1201 			pback(hdbuf, hdsz);
1202 			return(0);
1203 		}
1204 
1205 		/*
1206 		 * We have a flawed archive, no match. we start searching, but
1207 		 * we never allow additions to flawed archives
1208 		 */
1209 		if (!notice) {
1210 			if (act == APPND)
1211 				return(-1);
1212 			paxwarn(1, "Cannot identify format. Searching...");
1213 			++notice;
1214 		}
1215 
1216 		/*
1217 		 * brute force search for a header that we can id.
1218 		 * we shift through byte at a time. this is slow, but we cannot
1219 		 * determine the nature of the flaw in the archive in a
1220 		 * portable manner
1221 		 */
1222 		if (--hdsz > 0) {
1223 			memmove(hdbuf, hdbuf+1, hdsz);
1224 			res = BLKMULT - hdsz;
1225 			hdend = hdbuf + hdsz;
1226 		} else {
1227 			res = BLKMULT;
1228 			hdend = hdbuf;
1229 			hdsz = 0;
1230 		}
1231 	}
1232 
1233     out:
1234 	/*
1235 	 * we cannot find a header, bow, apologize and quit
1236 	 */
1237 	paxwarn(1, "Sorry, unable to determine archive format.");
1238 	return(-1);
1239 }
1240