xref: /freebsd/bin/pax/ar_subs.c (revision 0b3105a37d7adcadcb720112fed4dc4e8040be99)
1 /*-
2  * Copyright (c) 1992 Keith Muller.
3  * Copyright (c) 1992, 1993
4  *	The Regents of the University of California.  All rights reserved.
5  *
6  * This code is derived from software contributed to Berkeley by
7  * Keith Muller of the University of California, San Diego.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  * 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.
20  *
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
31  * SUCH DAMAGE.
32  */
33 
34 #ifndef lint
35 #if 0
36 static char sccsid[] = "@(#)ar_subs.c	8.2 (Berkeley) 4/18/94";
37 #endif
38 #endif /* not lint */
39 #include <sys/cdefs.h>
40 __FBSDID("$FreeBSD$");
41 
42 #include <sys/types.h>
43 #include <sys/time.h>
44 #include <sys/stat.h>
45 #include <signal.h>
46 #include <string.h>
47 #include <stdio.h>
48 #include <fcntl.h>
49 #include <errno.h>
50 #include <unistd.h>
51 #include "pax.h"
52 #include "extern.h"
53 
54 static void wr_archive(ARCHD *, int is_app);
55 static int get_arc(void);
56 static int next_head(ARCHD *);
57 
58 /*
59  * Routines which control the overall operation modes of pax as specified by
60  * the user: list, append, read ...
61  */
62 
63 static char hdbuf[BLKMULT];		/* space for archive header on read */
64 u_long flcnt;				/* number of files processed */
65 
66 /*
67  * list()
68  *	list the contents of an archive which match user supplied pattern(s)
69  *	(no pattern matches all).
70  */
71 
72 void
73 list(void)
74 {
75 	ARCHD *arcn;
76 	int res;
77 	ARCHD archd;
78 	time_t now;
79 
80 	arcn = &archd;
81 	/*
82 	 * figure out archive type; pass any format specific options to the
83 	 * archive option processing routine; call the format init routine. We
84 	 * also save current time for ls_list() so we do not make a system
85 	 * call for each file we need to print. If verbose (vflag) start up
86 	 * the name and group caches.
87 	 */
88 	if ((get_arc() < 0) || ((*frmt->options)() < 0) ||
89 	    ((*frmt->st_rd)() < 0))
90 		return;
91 
92 	if (vflag && ((uidtb_start() < 0) || (gidtb_start() < 0)))
93 		return;
94 
95 	now = time(NULL);
96 
97 	/*
98 	 * step through the archive until the format says it is done
99 	 */
100 	while (next_head(arcn) == 0) {
101 		/*
102 		 * check for pattern, and user specified options match.
103 		 * When all patterns are matched we are done.
104 		 */
105 		if ((res = pat_match(arcn)) < 0)
106 			break;
107 
108 		if ((res == 0) && (sel_chk(arcn) == 0)) {
109 			/*
110 			 * pattern resulted in a selected file
111 			 */
112 			if (pat_sel(arcn) < 0)
113 				break;
114 
115 			/*
116 			 * modify the name as requested by the user if name
117 			 * survives modification, do a listing of the file
118 			 */
119 			if ((res = mod_name(arcn)) < 0)
120 				break;
121 			if (res == 0)
122 				ls_list(arcn, now, stdout);
123 		}
124 
125 		/*
126 		 * skip to next archive format header using values calculated
127 		 * by the format header read routine
128 		 */
129 		if (rd_skip(arcn->skip + arcn->pad) == 1)
130 			break;
131 	}
132 
133 	/*
134 	 * all done, let format have a chance to cleanup, and make sure that
135 	 * the patterns supplied by the user were all matched
136 	 */
137 	(void)(*frmt->end_rd)();
138 	(void)sigprocmask(SIG_BLOCK, &s_mask, NULL);
139 	ar_close();
140 	pat_chk();
141 }
142 
143 /*
144  * extract()
145  *	extract the member(s) of an archive as specified by user supplied
146  *	pattern(s) (no patterns extracts all members)
147  */
148 
149 void
150 extract(void)
151 {
152 	ARCHD *arcn;
153 	int res;
154 	off_t cnt;
155 	ARCHD archd;
156 	struct stat sb;
157 	int fd;
158 	time_t now;
159 
160 	arcn = &archd;
161 	/*
162 	 * figure out archive type; pass any format specific options to the
163 	 * archive option processing routine; call the format init routine;
164 	 * start up the directory modification time and access mode database
165 	 */
166 	if ((get_arc() < 0) || ((*frmt->options)() < 0) ||
167 	    ((*frmt->st_rd)() < 0) || (dir_start() < 0))
168 		return;
169 
170 	/*
171 	 * When we are doing interactive rename, we store the mapping of names
172 	 * so we can fix up hard links files later in the archive.
173 	 */
174 	if (iflag && (name_start() < 0))
175 		return;
176 
177 	now = time(NULL);
178 
179 	/*
180 	 * step through each entry on the archive until the format read routine
181 	 * says it is done
182 	 */
183 	while (next_head(arcn) == 0) {
184 
185 		/*
186 		 * check for pattern, and user specified options match. When
187 		 * all the patterns are matched we are done
188 		 */
189 		if ((res = pat_match(arcn)) < 0)
190 			break;
191 
192 		if ((res > 0) || (sel_chk(arcn) != 0)) {
193 			/*
194 			 * file is not selected. skip past any file data and
195 			 * padding and go back for the next archive member
196 			 */
197 			(void)rd_skip(arcn->skip + arcn->pad);
198 			continue;
199 		}
200 
201 		/*
202 		 * with -u or -D only extract when the archive member is newer
203 		 * than the file with the same name in the file system (nos
204 		 * test of being the same type is required).
205 		 * NOTE: this test is done BEFORE name modifications as
206 		 * specified by pax. this operation can be confusing to the
207 		 * user who might expect the test to be done on an existing
208 		 * file AFTER the name mod. In honesty the pax spec is probably
209 		 * flawed in this respect.
210 		 */
211 		if ((uflag || Dflag) && ((lstat(arcn->name, &sb) == 0))) {
212 			if (uflag && Dflag) {
213 				if ((arcn->sb.st_mtime <= sb.st_mtime) &&
214 				    (arcn->sb.st_ctime <= sb.st_ctime)) {
215 					(void)rd_skip(arcn->skip + arcn->pad);
216 					continue;
217 				}
218 			} else if (Dflag) {
219 				if (arcn->sb.st_ctime <= sb.st_ctime) {
220 					(void)rd_skip(arcn->skip + arcn->pad);
221 					continue;
222 				}
223 			} else if (arcn->sb.st_mtime <= sb.st_mtime) {
224 				(void)rd_skip(arcn->skip + arcn->pad);
225 				continue;
226 			}
227 		}
228 
229 		/*
230 		 * this archive member is now been selected. modify the name.
231 		 */
232 		if ((pat_sel(arcn) < 0) || ((res = mod_name(arcn)) < 0))
233 			break;
234 		if (res > 0) {
235 			/*
236 			 * a bad name mod, skip and purge name from link table
237 			 */
238 			purg_lnk(arcn);
239 			(void)rd_skip(arcn->skip + arcn->pad);
240 			continue;
241 		}
242 
243 		/*
244 		 * Non standard -Y and -Z flag. When the existing file is
245 		 * same age or newer skip
246 		 */
247 		if ((Yflag || Zflag) && ((lstat(arcn->name, &sb) == 0))) {
248 			if (Yflag && Zflag) {
249 				if ((arcn->sb.st_mtime <= sb.st_mtime) &&
250 				    (arcn->sb.st_ctime <= sb.st_ctime)) {
251 					(void)rd_skip(arcn->skip + arcn->pad);
252 					continue;
253 				}
254 			} else if (Yflag) {
255 				if (arcn->sb.st_ctime <= sb.st_ctime) {
256 					(void)rd_skip(arcn->skip + arcn->pad);
257 					continue;
258 				}
259 			} else if (arcn->sb.st_mtime <= sb.st_mtime) {
260 				(void)rd_skip(arcn->skip + arcn->pad);
261 				continue;
262 			}
263 		}
264 
265 		if (vflag) {
266 			if (vflag > 1)
267 				ls_list(arcn, now, listf);
268 			else {
269 				(void)fputs(arcn->name, listf);
270 				vfpart = 1;
271 			}
272 		}
273 
274 		/*
275 		 * if required, chdir around.
276 		 */
277 		if ((arcn->pat != NULL) && (arcn->pat->chdname != NULL))
278 			if (chdir(arcn->pat->chdname) != 0)
279 				syswarn(1, errno, "Cannot chdir to %s",
280 				    arcn->pat->chdname);
281 
282 		/*
283 		 * all ok, extract this member based on type
284 		 */
285 		if ((arcn->type != PAX_REG) && (arcn->type != PAX_CTG)) {
286 			/*
287 			 * process archive members that are not regular files.
288 			 * throw out padding and any data that might follow the
289 			 * header (as determined by the format).
290 			 */
291 			if ((arcn->type == PAX_HLK) || (arcn->type == PAX_HRG))
292 				res = lnk_creat(arcn);
293 			else
294 				res = node_creat(arcn);
295 
296 			(void)rd_skip(arcn->skip + arcn->pad);
297 			if (res < 0)
298 				purg_lnk(arcn);
299 
300 			if (vflag && vfpart) {
301 				(void)putc('\n', listf);
302 				vfpart = 0;
303 			}
304 			continue;
305 		}
306 		/*
307 		 * we have a file with data here. If we can not create it, skip
308 		 * over the data and purge the name from hard link table
309 		 */
310 		if ((fd = file_creat(arcn)) < 0) {
311 			(void)rd_skip(arcn->skip + arcn->pad);
312 			purg_lnk(arcn);
313 			continue;
314 		}
315 		/*
316 		 * extract the file from the archive and skip over padding and
317 		 * any unprocessed data
318 		 */
319 		res = (*frmt->rd_data)(arcn, fd, &cnt);
320 		file_close(arcn, fd);
321 		if (vflag && vfpart) {
322 			(void)putc('\n', listf);
323 			vfpart = 0;
324 		}
325 		if (!res)
326 			(void)rd_skip(cnt + arcn->pad);
327 
328 		/*
329 		 * if required, chdir around.
330 		 */
331 		if ((arcn->pat != NULL) && (arcn->pat->chdname != NULL))
332 			if (fchdir(cwdfd) != 0)
333 				syswarn(1, errno,
334 				    "Can't fchdir to starting directory");
335 	}
336 
337 	/*
338 	 * all done, restore directory modes and times as required; make sure
339 	 * all patterns supplied by the user were matched; block off signals
340 	 * to avoid chance for multiple entry into the cleanup code.
341 	 */
342 	(void)(*frmt->end_rd)();
343 	(void)sigprocmask(SIG_BLOCK, &s_mask, NULL);
344 	ar_close();
345 	proc_dir();
346 	pat_chk();
347 }
348 
349 /*
350  * wr_archive()
351  *	Write an archive. used in both creating a new archive and appends on
352  *	previously written archive.
353  */
354 
355 static void
356 wr_archive(ARCHD *arcn, int is_app)
357 {
358 	int res;
359 	int hlk;
360 	int wr_one;
361 	off_t cnt;
362 	int (*wrf)(ARCHD *);
363 	int fd = -1;
364 	time_t now;
365 
366 	/*
367 	 * if this format supports hard link storage, start up the database
368 	 * that detects them.
369 	 */
370 	if (((hlk = frmt->hlk) == 1) && (lnk_start() < 0))
371 		return;
372 
373 	/*
374 	 * start up the file traversal code and format specific write
375 	 */
376 	if ((ftree_start() < 0) || ((*frmt->st_wr)() < 0))
377 		return;
378 	wrf = frmt->wr;
379 
380 	/*
381 	 * When we are doing interactive rename, we store the mapping of names
382 	 * so we can fix up hard links files later in the archive.
383 	 */
384 	if (iflag && (name_start() < 0))
385 		return;
386 
387 	/*
388 	 * if this not append, and there are no files, we do no write a trailer
389 	 */
390 	wr_one = is_app;
391 
392 	now = time(NULL);
393 
394 	/*
395 	 * while there are files to archive, process them one at at time
396 	 */
397 	while (next_file(arcn) == 0) {
398 		/*
399 		 * check if this file meets user specified options match.
400 		 */
401 		if (sel_chk(arcn) != 0) {
402 			ftree_notsel();
403 			continue;
404 		}
405 		fd = -1;
406 		if (uflag) {
407 			/*
408 			 * only archive if this file is newer than a file with
409 			 * the same name that is already stored on the archive
410 			 */
411 			if ((res = chk_ftime(arcn)) < 0)
412 				break;
413 			if (res > 0)
414 				continue;
415 		}
416 
417 		/*
418 		 * this file is considered selected now. see if this is a hard
419 		 * link to a file already stored
420 		 */
421 		ftree_sel(arcn);
422 		if (hlk && (chk_lnk(arcn) < 0))
423 			break;
424 
425 		if ((arcn->type == PAX_REG) || (arcn->type == PAX_HRG) ||
426 		    (arcn->type == PAX_CTG)) {
427 			/*
428 			 * we will have to read this file. by opening it now we
429 			 * can avoid writing a header to the archive for a file
430 			 * we were later unable to read (we also purge it from
431 			 * the link table).
432 			 */
433 			if ((fd = open(arcn->org_name, O_RDONLY, 0)) < 0) {
434 				syswarn(1,errno, "Unable to open %s to read",
435 					arcn->org_name);
436 				purg_lnk(arcn);
437 				continue;
438 			}
439 		}
440 
441 		/*
442 		 * Now modify the name as requested by the user
443 		 */
444 		if ((res = mod_name(arcn)) < 0) {
445 			/*
446 			 * name modification says to skip this file, close the
447 			 * file and purge link table entry
448 			 */
449 			rdfile_close(arcn, &fd);
450 			purg_lnk(arcn);
451 			break;
452 		}
453 
454 		if ((res > 0) || (docrc && (set_crc(arcn, fd) < 0))) {
455 			/*
456 			 * unable to obtain the crc we need, close the file,
457 			 * purge link table entry
458 			 */
459 			rdfile_close(arcn, &fd);
460 			purg_lnk(arcn);
461 			continue;
462 		}
463 
464 		if (vflag) {
465 			if (vflag > 1)
466 				ls_list(arcn, now, listf);
467 			else {
468 				(void)fputs(arcn->name, listf);
469 				vfpart = 1;
470 			}
471 		}
472 		++flcnt;
473 
474 		/*
475 		 * looks safe to store the file, have the format specific
476 		 * routine write routine store the file header on the archive
477 		 */
478 		if ((res = (*wrf)(arcn)) < 0) {
479 			rdfile_close(arcn, &fd);
480 			break;
481 		}
482 		wr_one = 1;
483 		if (res > 0) {
484 			/*
485 			 * format write says no file data needs to be stored
486 			 * so we are done messing with this file
487 			 */
488 			if (vflag && vfpart) {
489 				(void)putc('\n', listf);
490 				vfpart = 0;
491 			}
492 			rdfile_close(arcn, &fd);
493 			continue;
494 		}
495 
496 		/*
497 		 * Add file data to the archive, quit on write error. if we
498 		 * cannot write the entire file contents to the archive we
499 		 * must pad the archive to replace the missing file data
500 		 * (otherwise during an extract the file header for the file
501 		 * which FOLLOWS this one will not be where we expect it to
502 		 * be).
503 		 */
504 		res = (*frmt->wr_data)(arcn, fd, &cnt);
505 		rdfile_close(arcn, &fd);
506 		if (vflag && vfpart) {
507 			(void)putc('\n', listf);
508 			vfpart = 0;
509 		}
510 		if (res < 0)
511 			break;
512 
513 		/*
514 		 * pad as required, cnt is number of bytes not written
515 		 */
516 		if (((cnt > 0) && (wr_skip(cnt) < 0)) ||
517 		    ((arcn->pad > 0) && (wr_skip(arcn->pad) < 0)))
518 			break;
519 	}
520 
521 	/*
522 	 * tell format to write trailer; pad to block boundary; reset directory
523 	 * mode/access times, and check if all patterns supplied by the user
524 	 * were matched. block off signals to avoid chance for multiple entry
525 	 * into the cleanup code
526 	 */
527 	if (wr_one) {
528 		(*frmt->end_wr)();
529 		wr_fin();
530 	}
531 	(void)sigprocmask(SIG_BLOCK, &s_mask, NULL);
532 	ar_close();
533 	if (tflag)
534 		proc_dir();
535 	ftree_chk();
536 }
537 
538 /*
539  * append()
540  *	Add file to previously written archive. Archive format specified by the
541  *	user must agree with archive. The archive is read first to collect
542  *	modification times (if -u) and locate the archive trailer. The archive
543  *	is positioned in front of the record with the trailer and wr_archive()
544  *	is called to add the new members.
545  *	PAX IMPLEMENTATION DETAIL NOTE:
546  *	-u is implemented by adding the new members to the end of the archive.
547  *	Care is taken so that these do not end up as links to the older
548  *	version of the same file already stored in the archive. It is expected
549  *	when extraction occurs these newer versions will over-write the older
550  *	ones stored "earlier" in the archive (this may be a bad assumption as
551  *	it depends on the implementation of the program doing the extraction).
552  *	It is really difficult to splice in members without either re-writing
553  *	the entire archive (from the point were the old version was), or having
554  *	assistance of the format specification in terms of a special update
555  *	header that invalidates a previous archive record. The POSIX spec left
556  *	the method used to implement -u unspecified. This pax is able to
557  *	over write existing files that it creates.
558  */
559 
560 void
561 append(void)
562 {
563 	ARCHD *arcn;
564 	int res;
565 	ARCHD archd;
566 	FSUB *orgfrmt;
567 	int udev;
568 	off_t tlen;
569 
570 	arcn = &archd;
571 	orgfrmt = frmt;
572 
573 	/*
574 	 * Do not allow an append operation if the actual archive is of a
575 	 * different format than the user specified format.
576 	 */
577 	if (get_arc() < 0)
578 		return;
579 	if ((orgfrmt != NULL) && (orgfrmt != frmt)) {
580 		paxwarn(1, "Cannot mix current archive format %s with %s",
581 		    frmt->name, orgfrmt->name);
582 		return;
583 	}
584 
585 	/*
586 	 * pass the format any options and start up format
587 	 */
588 	if (((*frmt->options)() < 0) || ((*frmt->st_rd)() < 0))
589 		return;
590 
591 	/*
592 	 * if we only are adding members that are newer, we need to save the
593 	 * mod times for all files we see.
594 	 */
595 	if (uflag && (ftime_start() < 0))
596 		return;
597 
598 	/*
599 	 * some archive formats encode hard links by recording the device and
600 	 * file serial number (inode) but copy the file anyway (multiple times)
601 	 * to the archive. When we append, we run the risk that newly added
602 	 * files may have the same device and inode numbers as those recorded
603 	 * on the archive but during a previous run. If this happens, when the
604 	 * archive is extracted we get INCORRECT hard links. We avoid this by
605 	 * remapping the device numbers so that newly added files will never
606 	 * use the same device number as one found on the archive. remapping
607 	 * allows new members to safely have links among themselves. remapping
608 	 * also avoids problems with file inode (serial number) truncations
609 	 * when the inode number is larger than storage space in the archive
610 	 * header. See the remap routines for more details.
611 	 */
612 	if ((udev = frmt->udev) && (dev_start() < 0))
613 		return;
614 
615 	/*
616 	 * reading the archive may take a long time. If verbose tell the user
617 	 */
618 	if (vflag) {
619 		(void)fprintf(listf,
620 			"%s: Reading archive to position at the end...", argv0);
621 		vfpart = 1;
622 	}
623 
624 	/*
625 	 * step through the archive until the format says it is done
626 	 */
627 	while (next_head(arcn) == 0) {
628 		/*
629 		 * check if this file meets user specified options.
630 		 */
631 		if (sel_chk(arcn) != 0) {
632 			if (rd_skip(arcn->skip + arcn->pad) == 1)
633 				break;
634 			continue;
635 		}
636 
637 		if (uflag) {
638 			/*
639 			 * see if this is the newest version of this file has
640 			 * already been seen, if so skip.
641 			 */
642 			if ((res = chk_ftime(arcn)) < 0)
643 				break;
644 			if (res > 0) {
645 				if (rd_skip(arcn->skip + arcn->pad) == 1)
646 					break;
647 				continue;
648 			}
649 		}
650 
651 		/*
652 		 * Store this device number. Device numbers seen during the
653 		 * read phase of append will cause newly appended files with a
654 		 * device number seen in the old part of the archive to be
655 		 * remapped to an unused device number.
656 		 */
657 		if ((udev && (add_dev(arcn) < 0)) ||
658 		    (rd_skip(arcn->skip + arcn->pad) == 1))
659 			break;
660 	}
661 
662 	/*
663 	 * done, finish up read and get the number of bytes to back up so we
664 	 * can add new members. The format might have used the hard link table,
665 	 * purge it.
666 	 */
667 	tlen = (*frmt->end_rd)();
668 	lnk_end();
669 
670 	/*
671 	 * try to position for write, if this fails quit. if any error occurs,
672 	 * we will refuse to write
673 	 */
674 	if (appnd_start(tlen) < 0)
675 		return;
676 
677 	/*
678 	 * tell the user we are done reading.
679 	 */
680 	if (vflag && vfpart) {
681 		(void)fputs("done.\n", listf);
682 		vfpart = 0;
683 	}
684 
685 	/*
686 	 * go to the writing phase to add the new members
687 	 */
688 	wr_archive(arcn, 1);
689 }
690 
691 /*
692  * archive()
693  *	write a new archive
694  */
695 
696 void
697 archive(void)
698 {
699 	ARCHD archd;
700 
701 	/*
702 	 * if we only are adding members that are newer, we need to save the
703 	 * mod times for all files; set up for writing; pass the format any
704 	 * options write the archive
705 	 */
706 	if ((uflag && (ftime_start() < 0)) || (wr_start() < 0))
707 		return;
708 	if ((*frmt->options)() < 0)
709 		return;
710 
711 	wr_archive(&archd, 0);
712 }
713 
714 /*
715  * copy()
716  *	copy files from one part of the file system to another. this does not
717  *	use any archive storage. The EFFECT OF THE COPY IS THE SAME as if an
718  *	archive was written and then extracted in the destination directory
719  *	(except the files are forced to be under the destination directory).
720  */
721 
722 void
723 copy(void)
724 {
725 	ARCHD *arcn;
726 	int res;
727 	int fddest;
728 	char *dest_pt;
729 	int dlen;
730 	int drem;
731 	int fdsrc = -1;
732 	struct stat sb;
733 	ARCHD archd;
734 	char dirbuf[PAXPATHLEN+1];
735 
736 	arcn = &archd;
737 	/*
738 	 * set up the destination dir path and make sure it is a directory. We
739 	 * make sure we have a trailing / on the destination
740 	 */
741 	dlen = l_strncpy(dirbuf, dirptr, sizeof(dirbuf) - 1);
742 	dest_pt = dirbuf + dlen;
743 	if (*(dest_pt-1) != '/') {
744 		*dest_pt++ = '/';
745 		++dlen;
746 	}
747 	*dest_pt = '\0';
748 	drem = PAXPATHLEN - dlen;
749 
750 	if (stat(dirptr, &sb) < 0) {
751 		syswarn(1, errno, "Cannot access destination directory %s",
752 			dirptr);
753 		return;
754 	}
755 	if (!S_ISDIR(sb.st_mode)) {
756 		paxwarn(1, "Destination is not a directory %s", dirptr);
757 		return;
758 	}
759 
760 	/*
761 	 * start up the hard link table; file traversal routines and the
762 	 * modification time and access mode database
763 	 */
764 	if ((lnk_start() < 0) || (ftree_start() < 0) || (dir_start() < 0))
765 		return;
766 
767 	/*
768 	 * When we are doing interactive rename, we store the mapping of names
769 	 * so we can fix up hard links files later in the archive.
770 	 */
771 	if (iflag && (name_start() < 0))
772 		return;
773 
774 	/*
775 	 * set up to cp file trees
776 	 */
777 	cp_start();
778 
779 	/*
780 	 * while there are files to archive, process them
781 	 */
782 	while (next_file(arcn) == 0) {
783 		fdsrc = -1;
784 
785 		/*
786 		 * check if this file meets user specified options
787 		 */
788 		if (sel_chk(arcn) != 0) {
789 			ftree_notsel();
790 			continue;
791 		}
792 
793 		/*
794 		 * if there is already a file in the destination directory with
795 		 * the same name and it is newer, skip the one stored on the
796 		 * archive.
797 		 * NOTE: this test is done BEFORE name modifications as
798 		 * specified by pax. this can be confusing to the user who
799 		 * might expect the test to be done on an existing file AFTER
800 		 * the name mod. In honesty the pax spec is probably flawed in
801 		 * this respect
802 		 */
803 		if (uflag || Dflag) {
804 			/*
805 			 * create the destination name
806 			 */
807 			if (*(arcn->name) == '/')
808 				res = 1;
809 			else
810 				res = 0;
811 			if ((arcn->nlen - res) > drem) {
812 				paxwarn(1, "Destination pathname too long %s",
813 					arcn->name);
814 				continue;
815 			}
816 			(void)strncpy(dest_pt, arcn->name + res, drem);
817 			dirbuf[PAXPATHLEN] = '\0';
818 
819 			/*
820 			 * if existing file is same age or newer skip
821 			 */
822 			res = lstat(dirbuf, &sb);
823 			*dest_pt = '\0';
824 
825 		    	if (res == 0) {
826 				if (uflag && Dflag) {
827 					if ((arcn->sb.st_mtime<=sb.st_mtime) &&
828 			    		    (arcn->sb.st_ctime<=sb.st_ctime))
829 						continue;
830 				} else if (Dflag) {
831 					if (arcn->sb.st_ctime <= sb.st_ctime)
832 						continue;
833 				} else if (arcn->sb.st_mtime <= sb.st_mtime)
834 					continue;
835 			}
836 		}
837 
838 		/*
839 		 * this file is considered selected. See if this is a hard link
840 		 * to a previous file; modify the name as requested by the
841 		 * user; set the final destination.
842 		 */
843 		ftree_sel(arcn);
844 		if ((chk_lnk(arcn) < 0) || ((res = mod_name(arcn)) < 0))
845 			break;
846 		if ((res > 0) || (set_dest(arcn, dirbuf, dlen) < 0)) {
847 			/*
848 			 * skip file, purge from link table
849 			 */
850 			purg_lnk(arcn);
851 			continue;
852 		}
853 
854 		/*
855 		 * Non standard -Y and -Z flag. When the existing file is
856 		 * same age or newer skip
857 		 */
858 		if ((Yflag || Zflag) && ((lstat(arcn->name, &sb) == 0))) {
859 			if (Yflag && Zflag) {
860 				if ((arcn->sb.st_mtime <= sb.st_mtime) &&
861 				    (arcn->sb.st_ctime <= sb.st_ctime))
862 					continue;
863 			} else if (Yflag) {
864 				if (arcn->sb.st_ctime <= sb.st_ctime)
865 					continue;
866 			} else if (arcn->sb.st_mtime <= sb.st_mtime)
867 				continue;
868 		}
869 
870 		if (vflag) {
871 			(void)fputs(arcn->name, listf);
872 			vfpart = 1;
873 		}
874 		++flcnt;
875 
876 		/*
877 		 * try to create a hard link to the src file if requested
878 		 * but make sure we are not trying to overwrite ourselves.
879 		 */
880 		if (lflag)
881 			res = cross_lnk(arcn);
882 		else
883 			res = chk_same(arcn);
884 		if (res <= 0) {
885 			if (vflag && vfpart) {
886 				(void)putc('\n', listf);
887 				vfpart = 0;
888 			}
889 			continue;
890 		}
891 
892 		/*
893 		 * have to create a new file
894 		 */
895 		if ((arcn->type != PAX_REG) && (arcn->type != PAX_CTG)) {
896 			/*
897 			 * create a link or special file
898 			 */
899 			if ((arcn->type == PAX_HLK) || (arcn->type == PAX_HRG))
900 				res = lnk_creat(arcn);
901 			else
902 				res = node_creat(arcn);
903 			if (res < 0)
904 				purg_lnk(arcn);
905 			if (vflag && vfpart) {
906 				(void)putc('\n', listf);
907 				vfpart = 0;
908 			}
909 			continue;
910 		}
911 
912 		/*
913 		 * have to copy a regular file to the destination directory.
914 		 * first open source file and then create the destination file
915 		 */
916 		if ((fdsrc = open(arcn->org_name, O_RDONLY, 0)) < 0) {
917 			syswarn(1, errno, "Unable to open %s to read",
918 			    arcn->org_name);
919 			purg_lnk(arcn);
920 			continue;
921 		}
922 		if ((fddest = file_creat(arcn)) < 0) {
923 			rdfile_close(arcn, &fdsrc);
924 			purg_lnk(arcn);
925 			continue;
926 		}
927 
928 		/*
929 		 * copy source file data to the destination file
930 		 */
931 		cp_file(arcn, fdsrc, fddest);
932 		file_close(arcn, fddest);
933 		rdfile_close(arcn, &fdsrc);
934 
935 		if (vflag && vfpart) {
936 			(void)putc('\n', listf);
937 			vfpart = 0;
938 		}
939 	}
940 
941 	/*
942 	 * restore directory modes and times as required; make sure all
943 	 * patterns were selected block off signals to avoid chance for
944 	 * multiple entry into the cleanup code.
945 	 */
946 	(void)sigprocmask(SIG_BLOCK, &s_mask, NULL);
947 	ar_close();
948 	proc_dir();
949 	ftree_chk();
950 }
951 
952 /*
953  * next_head()
954  *	try to find a valid header in the archive. Uses format specific
955  *	routines to extract the header and id the trailer. Trailers may be
956  *	located within a valid header or in an invalid header (the location
957  *	is format specific. The inhead field from the option table tells us
958  *	where to look for the trailer).
959  *	We keep reading (and resyncing) until we get enough contiguous data
960  *	to check for a header. If we cannot find one, we shift by a byte
961  *	add a new byte from the archive to the end of the buffer and try again.
962  *	If we get a read error, we throw out what we have (as we must have
963  *	contiguous data) and start over again.
964  *	ASSUMED: headers fit within a BLKMULT header.
965  * Return:
966  *	0 if we got a header, -1 if we are unable to ever find another one
967  *	(we reached the end of input, or we reached the limit on retries. see
968  *	the specs for rd_wrbuf() for more details)
969  */
970 
971 static int
972 next_head(ARCHD *arcn)
973 {
974 	int ret;
975 	char *hdend;
976 	int res;
977 	int shftsz;
978 	int hsz;
979 	int in_resync = 0; 	/* set when we are in resync mode */
980 	int cnt = 0;			/* counter for trailer function */
981 	int first = 1;			/* on 1st read, EOF isn't premature. */
982 
983 	/*
984 	 * set up initial conditions, we want a whole frmt->hsz block as we
985 	 * have no data yet.
986 	 */
987 	res = hsz = frmt->hsz;
988 	hdend = hdbuf;
989 	shftsz = hsz - 1;
990 	for(;;) {
991 		/*
992 		 * keep looping until we get a contiguous FULL buffer
993 		 * (frmt->hsz is the proper size)
994 		 */
995 		for (;;) {
996 			if ((ret = rd_wrbuf(hdend, res)) == res)
997 				break;
998 
999 			/*
1000 			 * If we read 0 bytes (EOF) from an archive when we
1001 			 * expect to find a header, we have stepped upon
1002 			 * an archive without the customary block of zeroes
1003 			 * end marker.  It's just stupid to error out on
1004 			 * them, so exit gracefully.
1005 			 */
1006 			if (first && ret == 0)
1007 				return(-1);
1008 			first = 0;
1009 
1010 			/*
1011 			 * some kind of archive read problem, try to resync the
1012 			 * storage device, better give the user the bad news.
1013 			 */
1014 			if ((ret == 0) || (rd_sync() < 0)) {
1015 				paxwarn(1,"Premature end of file on archive read");
1016 				return(-1);
1017 			}
1018 			if (!in_resync) {
1019 				if (act == APPND) {
1020 					paxwarn(1,
1021 					  "Archive I/O error, cannot continue");
1022 					return(-1);
1023 				}
1024 				paxwarn(1,"Archive I/O error. Trying to recover.");
1025 				++in_resync;
1026 			}
1027 
1028 			/*
1029 			 * oh well, throw it all out and start over
1030 			 */
1031 			res = hsz;
1032 			hdend = hdbuf;
1033 		}
1034 
1035 		/*
1036 		 * ok we have a contiguous buffer of the right size. Call the
1037 		 * format read routine. If this was not a valid header and this
1038 		 * format stores trailers outside of the header, call the
1039 		 * format specific trailer routine to check for a trailer. We
1040 		 * have to watch out that we do not mis-identify file data or
1041 		 * block padding as a header or trailer. Format specific
1042 		 * trailer functions must NOT check for the trailer while we
1043 		 * are running in resync mode. Some trailer functions may tell
1044 		 * us that this block cannot contain a valid header either, so
1045 		 * we then throw out the entire block and start over.
1046 		 */
1047 		if ((*frmt->rd)(arcn, hdbuf) == 0)
1048 			break;
1049 
1050 		if (!frmt->inhead) {
1051 			/*
1052 			 * this format has trailers outside of valid headers
1053 			 */
1054 			if ((ret = (*frmt->trail_tar)(hdbuf,in_resync,&cnt)) == 0){
1055 				/*
1056 				 * valid trailer found, drain input as required
1057 				 */
1058 				ar_drain();
1059 				return(-1);
1060 			}
1061 
1062 			if (ret == 1) {
1063 				/*
1064 				 * we are in resync and we were told to throw
1065 				 * the whole block out because none of the
1066 				 * bytes in this block can be used to form a
1067 				 * valid header
1068 				 */
1069 				res = hsz;
1070 				hdend = hdbuf;
1071 				continue;
1072 			}
1073 		}
1074 
1075 		/*
1076 		 * Brute force section.
1077 		 * not a valid header. We may be able to find a header yet. So
1078 		 * we shift over by one byte, and set up to read one byte at a
1079 		 * time from the archive and place it at the end of the buffer.
1080 		 * We will keep moving byte at a time until we find a header or
1081 		 * get a read error and have to start over.
1082 		 */
1083 		if (!in_resync) {
1084 			if (act == APPND) {
1085 				paxwarn(1,"Unable to append, archive header flaw");
1086 				return(-1);
1087 			}
1088 			paxwarn(1,"Invalid header, starting valid header search.");
1089 			++in_resync;
1090 		}
1091 		memmove(hdbuf, hdbuf+1, shftsz);
1092 		res = 1;
1093 		hdend = hdbuf + shftsz;
1094 	}
1095 
1096 	/*
1097 	 * ok got a valid header, check for trailer if format encodes it in
1098 	 * the header.
1099 	 */
1100 	if (frmt->inhead && ((*frmt->trail_cpio)(arcn) == 0)) {
1101 		/*
1102 		 * valid trailer found, drain input as required
1103 		 */
1104 		ar_drain();
1105 		return(-1);
1106 	}
1107 
1108 	++flcnt;
1109 	return(0);
1110 }
1111 
1112 /*
1113  * get_arc()
1114  *	Figure out what format an archive is. Handles archive with flaws by
1115  *	brute force searches for a legal header in any supported format. The
1116  *	format id routines have to be careful to NOT mis-identify a format.
1117  *	ASSUMED: headers fit within a BLKMULT header.
1118  * Return:
1119  *	0 if archive found -1 otherwise
1120  */
1121 
1122 static int
1123 get_arc(void)
1124 {
1125 	int i;
1126 	int hdsz = 0;
1127 	int res;
1128 	int minhd = BLKMULT;
1129 	char *hdend;
1130 	int notice = 0;
1131 
1132 	/*
1133 	 * find the smallest header size in all archive formats and then set up
1134 	 * to read the archive.
1135 	 */
1136 	for (i = 0; ford[i] >= 0; ++i) {
1137 		if (fsub[ford[i]].hsz < minhd)
1138 			minhd = fsub[ford[i]].hsz;
1139 	}
1140 	if (rd_start() < 0)
1141 		return(-1);
1142 	res = BLKMULT;
1143 	hdsz = 0;
1144 	hdend = hdbuf;
1145 	for(;;) {
1146 		for (;;) {
1147 			/*
1148 			 * fill the buffer with at least the smallest header
1149 			 */
1150 			i = rd_wrbuf(hdend, res);
1151 			if (i > 0)
1152 				hdsz += i;
1153 			if (hdsz >= minhd)
1154 				break;
1155 
1156 			/*
1157 			 * if we cannot recover from a read error quit
1158 			 */
1159 			if ((i == 0) || (rd_sync() < 0))
1160 				goto out;
1161 
1162 			/*
1163 			 * when we get an error none of the data we already
1164 			 * have can be used to create a legal header (we just
1165 			 * got an error in the middle), so we throw it all out
1166 			 * and refill the buffer with fresh data.
1167 			 */
1168 			res = BLKMULT;
1169 			hdsz = 0;
1170 			hdend = hdbuf;
1171 			if (!notice) {
1172 				if (act == APPND)
1173 					return(-1);
1174 				paxwarn(1,"Cannot identify format. Searching...");
1175 				++notice;
1176 			}
1177 		}
1178 
1179 		/*
1180 		 * we have at least the size of the smallest header in any
1181 		 * archive format. Look to see if we have a match. The array
1182 		 * ford[] is used to specify the header id order to reduce the
1183 		 * chance of incorrectly id'ing a valid header (some formats
1184 		 * may be subsets of each other and the order would then be
1185 		 * important).
1186 		 */
1187 		for (i = 0; ford[i] >= 0; ++i) {
1188 			if ((*fsub[ford[i]].id)(hdbuf, hdsz) < 0)
1189 				continue;
1190 			frmt = &(fsub[ford[i]]);
1191 			/*
1192 			 * yuck, to avoid slow special case code in the extract
1193 			 * routines, just push this header back as if it was
1194 			 * not seen. We have left extra space at start of the
1195 			 * buffer for this purpose. This is a bit ugly, but
1196 			 * adding all the special case code is far worse.
1197 			 */
1198 			pback(hdbuf, hdsz);
1199 			return(0);
1200 		}
1201 
1202 		/*
1203 		 * We have a flawed archive, no match. we start searching, but
1204 		 * we never allow additions to flawed archives
1205 		 */
1206 		if (!notice) {
1207 			if (act == APPND)
1208 				return(-1);
1209 			paxwarn(1, "Cannot identify format. Searching...");
1210 			++notice;
1211 		}
1212 
1213 		/*
1214 		 * brute force search for a header that we can id.
1215 		 * we shift through byte at a time. this is slow, but we cannot
1216 		 * determine the nature of the flaw in the archive in a
1217 		 * portable manner
1218 		 */
1219 		if (--hdsz > 0) {
1220 			memmove(hdbuf, hdbuf+1, hdsz);
1221 			res = BLKMULT - hdsz;
1222 			hdend = hdbuf + hdsz;
1223 		} else {
1224 			res = BLKMULT;
1225 			hdend = hdbuf;
1226 			hdsz = 0;
1227 		}
1228 	}
1229 
1230     out:
1231 	/*
1232 	 * we cannot find a header, bow, apologize and quit
1233 	 */
1234 	paxwarn(1, "Sorry, unable to determine archive format.");
1235 	return(-1);
1236 }
1237