tar.c revision 1.51
1/*	$NetBSD: tar.c,v 1.51 2004/04/20 19:59:54 christos Exp $	*/
2
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#if HAVE_NBTOOL_CONFIG_H
37#include "nbtool_config.h"
38#endif
39
40#include <sys/cdefs.h>
41#if !defined(lint)
42#if 0
43static char sccsid[] = "@(#)tar.c	8.2 (Berkeley) 4/18/94";
44#else
45__RCSID("$NetBSD: tar.c,v 1.51 2004/04/20 19:59:54 christos Exp $");
46#endif
47#endif /* not lint */
48
49#include <sys/types.h>
50#include <sys/time.h>
51#include <sys/stat.h>
52#include <sys/param.h>
53
54#include <ctype.h>
55#include <errno.h>
56#include <grp.h>
57#include <pwd.h>
58#include <stdio.h>
59#include <stdlib.h>
60#include <string.h>
61#include <unistd.h>
62
63#include "pax.h"
64#include "extern.h"
65#include "tar.h"
66
67/*
68 * Routines for reading, writing and header identify of various versions of tar
69 */
70
71static int expandname(char *, size_t,  char **, const char *, size_t);
72static void longlink(ARCHD *);
73static u_long tar_chksm(char *, int);
74static char *name_split(char *, int);
75static int ul_oct(u_long, char *, int, int);
76#if !defined(NET2_STAT) && !defined(_LP64)
77static int ull_oct(unsigned long long, char *, int, int);
78#endif
79static int tar_gnutar_exclude_one(const char *, size_t);
80static int check_sum(char *, size_t, char *, size_t, int);
81
82/*
83 * Routines common to all versions of tar
84 */
85
86static int tar_nodir;			/* do not write dirs under old tar */
87int is_gnutar;				/* behave like gnu tar; enable gnu
88					 * extensions and skip end-ofvolume
89					 * checks
90					 */
91static int seen_gnu_warning;		/* Have we warned yet? */
92static char *gnu_hack_string;		/* ././@LongLink hackery */
93static int gnu_hack_len;		/* len of gnu_hack_string */
94char *gnu_name_string;			/* ././@LongLink hackery name */
95char *gnu_link_string;			/* ././@LongLink hackery link */
96
97static int
98check_sum(char *hd, size_t hdlen, char *bl, size_t bllen, int quiet)
99{
100	u_long hdck, blck;
101
102	hdck = asc_ul(hd, hdlen, OCT);
103	blck = tar_chksm(bl, bllen);
104
105	if (hdck != blck) {
106		if (!quiet)
107			tty_warn(0, "Header checksum %lo does not match %lo",
108			    hdck, blck);
109		return(-1);
110	}
111	return(0);
112}
113
114
115/*
116 * tar_endwr()
117 *	add the tar trailer of two null blocks
118 * Return:
119 *	0 if ok, -1 otherwise (what wr_skip returns)
120 */
121
122int
123tar_endwr(void)
124{
125	return(wr_skip((off_t)(NULLCNT*BLKMULT)));
126}
127
128/*
129 * tar_endrd()
130 *	no cleanup needed here, just return size of trailer (for append)
131 * Return:
132 *	size of trailer BLKMULT
133 */
134
135off_t
136tar_endrd(void)
137{
138	return((off_t)(NULLCNT*BLKMULT));
139}
140
141/*
142 * tar_trail()
143 *	Called to determine if a header block is a valid trailer. We are passed
144 *	the block, the in_sync flag (which tells us we are in resync mode;
145 *	looking for a valid header), and cnt (which starts at zero) which is
146 *	used to count the number of empty blocks we have seen so far.
147 * Return:
148 *	0 if a valid trailer, -1 if not a valid trailer, or 1 if the block
149 *	could never contain a header.
150 */
151
152int
153tar_trail(char *buf, int in_resync, int *cnt)
154{
155	int i;
156
157	/*
158	 * look for all zero, trailer is two consecutive blocks of zero
159	 */
160	for (i = 0; i < BLKMULT; ++i) {
161		if (buf[i] != '\0')
162			break;
163	}
164
165	/*
166	 * if not all zero it is not a trailer, but MIGHT be a header.
167	 */
168	if (i != BLKMULT)
169		return(-1);
170
171	/*
172	 * When given a zero block, we must be careful!
173	 * If we are not in resync mode, check for the trailer. Have to watch
174	 * out that we do not mis-identify file data as the trailer, so we do
175	 * NOT try to id a trailer during resync mode. During resync mode we
176	 * might as well throw this block out since a valid header can NEVER be
177	 * a block of all 0 (we must have a valid file name).
178	 */
179	if (!in_resync) {
180		++*cnt;
181#if 0
182		/*
183		 * old GNU tar (up through 1.13) only writes one block of
184		 * trailers, so we pretend we got another
185		 */
186		if (is_gnutar)
187			++*cnt;
188#endif
189		if (*cnt >= NULLCNT)
190			return(0);
191	}
192	return(1);
193}
194
195/*
196 * ul_oct()
197 *	convert an unsigned long to an octal string. many oddball field
198 *	termination characters are used by the various versions of tar in the
199 *	different fields. term selects which kind to use. str is '0' padded
200 *	at the front to len. we are unable to use only one format as many old
201 *	tar readers are very cranky about this.
202 * Return:
203 *	0 if the number fit into the string, -1 otherwise
204 */
205
206static int
207ul_oct(u_long val, char *str, int len, int term)
208{
209	char *pt;
210
211	/*
212	 * term selects the appropriate character(s) for the end of the string
213	 */
214	pt = str + len - 1;
215	switch(term) {
216	case 3:
217		*pt-- = '\0';
218		break;
219	case 2:
220		*pt-- = ' ';
221		*pt-- = '\0';
222		break;
223	case 1:
224		*pt-- = ' ';
225		break;
226	case 0:
227	default:
228		*pt-- = '\0';
229		*pt-- = ' ';
230		break;
231	}
232
233	/*
234	 * convert and blank pad if there is space
235	 */
236	while (pt >= str) {
237		*pt-- = '0' + (char)(val & 0x7);
238		if ((val = val >> 3) == (u_long)0)
239			break;
240	}
241
242	while (pt >= str)
243		*pt-- = '0';
244	if (val != (u_long)0)
245		return(-1);
246	return(0);
247}
248
249#if !defined(NET2_STAT) && !defined(_LP64)
250/*
251 * ull_oct()
252 *	convert an unsigned long long to an octal string. one of many oddball
253 *	field termination characters are used by the various versions of tar
254 *	in the different fields. term selects which kind to use. str is '0'
255 *	padded at the front to len. we are unable to use only one format as
256 *	many old tar readers are very cranky about this.
257 * Return:
258 *	0 if the number fit into the string, -1 otherwise
259 */
260
261static int
262ull_oct(unsigned long long val, char *str, int len, int term)
263{
264	char *pt;
265
266	/*
267	 * term selects the appropriate character(s) for the end of the string
268	 */
269	pt = str + len - 1;
270	switch(term) {
271	case 3:
272		*pt-- = '\0';
273		break;
274	case 2:
275		*pt-- = ' ';
276		*pt-- = '\0';
277		break;
278	case 1:
279		*pt-- = ' ';
280		break;
281	case 0:
282	default:
283		*pt-- = '\0';
284		*pt-- = ' ';
285		break;
286	}
287
288	/*
289	 * convert and blank pad if there is space
290	 */
291	while (pt >= str) {
292		*pt-- = '0' + (char)(val & 0x7);
293		if ((val = val >> 3) == 0)
294			break;
295	}
296
297	while (pt >= str)
298		*pt-- = '0';
299	if (val != (unsigned long long)0)
300		return(-1);
301	return(0);
302}
303#endif
304
305/*
306 * tar_chksm()
307 *	calculate the checksum for a tar block counting the checksum field as
308 *	all blanks (BLNKSUM is that value pre-calculated, the sum of 8 blanks).
309 *	NOTE: we use len to short circuit summing 0's on write since we ALWAYS
310 *	pad headers with 0.
311 * Return:
312 *	unsigned long checksum
313 */
314
315static u_long
316tar_chksm(char *blk, int len)
317{
318	char *stop;
319	char *pt;
320	u_long chksm = BLNKSUM;	/* initial value is checksum field sum */
321
322	/*
323	 * add the part of the block before the checksum field
324	 */
325	pt = blk;
326	stop = blk + CHK_OFFSET;
327	while (pt < stop)
328		chksm += (u_long)(*pt++ & 0xff);
329	/*
330	 * move past the checksum field and keep going, spec counts the
331	 * checksum field as the sum of 8 blanks (which is pre-computed as
332	 * BLNKSUM).
333	 * ASSUMED: len is greater than CHK_OFFSET. (len is where our 0 padding
334	 * starts, no point in summing zero's)
335	 */
336	pt += CHK_LEN;
337	stop = blk + len;
338	while (pt < stop)
339		chksm += (u_long)(*pt++ & 0xff);
340	return(chksm);
341}
342
343/*
344 * Routines for old BSD style tar (also made portable to sysV tar)
345 */
346
347/*
348 * tar_id()
349 *	determine if a block given to us is a valid tar header (and not a USTAR
350 *	header). We have to be on the lookout for those pesky blocks of	all
351 *	zero's.
352 * Return:
353 *	0 if a tar header, -1 otherwise
354 */
355
356int
357tar_id(char *blk, int size)
358{
359	HD_TAR *hd;
360	HD_USTAR *uhd;
361
362	if (size < BLKMULT)
363		return(-1);
364	hd = (HD_TAR *)blk;
365	uhd = (HD_USTAR *)blk;
366
367	/*
368	 * check for block of zero's first, a simple and fast test, then make
369	 * sure this is not a ustar header by looking for the ustar magic
370	 * cookie. We should use TMAGLEN, but some USTAR archive programs are
371	 * wrong and create archives missing the \0. Last we check the
372	 * checksum. If this is ok we have to assume it is a valid header.
373	 */
374	if (hd->name[0] == '\0')
375		return(-1);
376	if (strncmp(uhd->magic, TMAGIC, TMAGLEN - 1) == 0)
377		return(-1);
378	return check_sum(hd->chksum, sizeof(hd->chksum), blk, BLKMULT, 1);
379}
380
381/*
382 * tar_opt()
383 *	handle tar format specific -o options
384 * Return:
385 *	0 if ok -1 otherwise
386 */
387
388int
389tar_opt(void)
390{
391	OPLIST *opt;
392
393	while ((opt = opt_next()) != NULL) {
394		if (strcmp(opt->name, TAR_OPTION) ||
395		    strcmp(opt->value, TAR_NODIR)) {
396			tty_warn(1,
397			    "Unknown tar format -o option/value pair %s=%s",
398			    opt->name, opt->value);
399			tty_warn(1,
400			    "%s=%s is the only supported tar format option",
401			    TAR_OPTION, TAR_NODIR);
402			return(-1);
403		}
404
405		/*
406		 * we only support one option, and only when writing
407		 */
408		if ((act != APPND) && (act != ARCHIVE)) {
409			tty_warn(1, "%s=%s is only supported when writing.",
410			    opt->name, opt->value);
411			return(-1);
412		}
413		tar_nodir = 1;
414	}
415	return(0);
416}
417
418
419/*
420 * tar_rd()
421 *	extract the values out of block already determined to be a tar header.
422 *	store the values in the ARCHD parameter.
423 * Return:
424 *	0
425 */
426
427int
428tar_rd(ARCHD *arcn, char *buf)
429{
430	HD_TAR *hd;
431	char *pt;
432
433	/*
434	 * we only get proper sized buffers passed to us
435	 */
436	if (tar_id(buf, BLKMULT) < 0)
437		return(-1);
438	memset(arcn, 0, sizeof(*arcn));
439	arcn->org_name = arcn->name;
440	arcn->pat = NULL;
441	arcn->sb.st_nlink = 1;
442
443	/*
444	 * copy out the name and values in the stat buffer
445	 */
446	hd = (HD_TAR *)buf;
447	if (hd->linkflag != LONGLINKTYPE && hd->linkflag != LONGNAMETYPE) {
448		arcn->nlen = expandname(arcn->name, sizeof(arcn->name),
449		    &gnu_name_string, hd->name, sizeof(hd->name));
450		arcn->ln_nlen = expandname(arcn->ln_name, sizeof(arcn->ln_name),
451		    &gnu_link_string, hd->linkname, sizeof(hd->linkname));
452	}
453	arcn->sb.st_mode = (mode_t)(asc_ul(hd->mode,sizeof(hd->mode),OCT) &
454	    0xfff);
455	arcn->sb.st_uid = (uid_t)asc_ul(hd->uid, sizeof(hd->uid), OCT);
456	arcn->sb.st_gid = (gid_t)asc_ul(hd->gid, sizeof(hd->gid), OCT);
457	arcn->sb.st_size = (off_t)ASC_OFFT(hd->size, sizeof(hd->size), OCT);
458	arcn->sb.st_mtime = (time_t)asc_ul(hd->mtime, sizeof(hd->mtime), OCT);
459	arcn->sb.st_ctime = arcn->sb.st_atime = arcn->sb.st_mtime;
460
461	/*
462	 * have to look at the last character, it may be a '/' and that is used
463	 * to encode this as a directory
464	 */
465	pt = &(arcn->name[arcn->nlen - 1]);
466	arcn->pad = 0;
467	arcn->skip = 0;
468	switch(hd->linkflag) {
469	case SYMTYPE:
470		/*
471		 * symbolic link, need to get the link name and set the type in
472		 * the st_mode so -v printing will look correct.
473		 */
474		arcn->type = PAX_SLK;
475		arcn->sb.st_mode |= S_IFLNK;
476		break;
477	case LNKTYPE:
478		/*
479		 * hard link, need to get the link name, set the type in the
480		 * st_mode and st_nlink so -v printing will look better.
481		 */
482		arcn->type = PAX_HLK;
483		arcn->sb.st_nlink = 2;
484
485		/*
486		 * no idea of what type this thing really points at, but
487		 * we set something for printing only.
488		 */
489		arcn->sb.st_mode |= S_IFREG;
490		break;
491	case LONGLINKTYPE:
492		arcn->type = PAX_GLL;
493		/* FALLTHROUGH */
494	case LONGNAMETYPE:
495		/*
496		 * GNU long link/file; we tag these here and let the
497		 * pax internals deal with it -- too ugly otherwise.
498		 */
499		if (hd->linkflag != LONGLINKTYPE)
500			arcn->type = PAX_GLF;
501		arcn->pad = TAR_PAD(arcn->sb.st_size);
502		arcn->skip = arcn->sb.st_size;
503		break;
504	case AREGTYPE:
505	case REGTYPE:
506	case DIRTYPE:	/* see below */
507	default:
508		/*
509		 * If we have a trailing / this is a directory and NOT a file.
510		 * Note: V7 tar doesn't actually have DIRTYPE, but it was
511		 * reported that V7 archives using USTAR directories do exist.
512		 */
513		if (*pt == '/' || hd->linkflag == DIRTYPE) {
514			/*
515			 * it is a directory, set the mode for -v printing
516			 */
517			arcn->type = PAX_DIR;
518			arcn->sb.st_mode |= S_IFDIR;
519			arcn->sb.st_nlink = 2;
520		} else {
521			/*
522			 * have a file that will be followed by data. Set the
523			 * skip value to the size field and calculate the size
524			 * of the padding.
525			 */
526			arcn->type = PAX_REG;
527			arcn->sb.st_mode |= S_IFREG;
528			arcn->pad = TAR_PAD(arcn->sb.st_size);
529			arcn->skip = arcn->sb.st_size;
530		}
531		break;
532	}
533
534	/*
535	 * strip off any trailing slash.
536	 */
537	if (*pt == '/') {
538		*pt = '\0';
539		--arcn->nlen;
540	}
541	return(0);
542}
543
544/*
545 * tar_wr()
546 *	write a tar header for the file specified in the ARCHD to the archive.
547 *	Have to check for file types that cannot be stored and file names that
548 *	are too long. Be careful of the term (last arg) to ul_oct, each field
549 *	of tar has it own spec for the termination character(s).
550 *	ASSUMED: space after header in header block is zero filled
551 * Return:
552 *	0 if file has data to be written after the header, 1 if file has NO
553 *	data to write after the header, -1 if archive write failed
554 */
555
556int
557tar_wr(ARCHD *arcn)
558{
559	HD_TAR *hd;
560	int len;
561	char hdblk[sizeof(HD_TAR)];
562
563	/*
564	 * check for those file system types which tar cannot store
565	 */
566	switch(arcn->type) {
567	case PAX_DIR:
568		/*
569		 * user asked that dirs not be written to the archive
570		 */
571		if (tar_nodir)
572			return(1);
573		break;
574	case PAX_CHR:
575		tty_warn(1, "Tar cannot archive a character device %s",
576		    arcn->org_name);
577		return(1);
578	case PAX_BLK:
579		tty_warn(1,
580		    "Tar cannot archive a block device %s", arcn->org_name);
581		return(1);
582	case PAX_SCK:
583		tty_warn(1, "Tar cannot archive a socket %s", arcn->org_name);
584		return(1);
585	case PAX_FIF:
586		tty_warn(1, "Tar cannot archive a fifo %s", arcn->org_name);
587		return(1);
588	case PAX_SLK:
589	case PAX_HLK:
590	case PAX_HRG:
591		if (arcn->ln_nlen > sizeof(hd->linkname)) {
592			tty_warn(1,"Link name too long for tar %s",
593			    arcn->ln_name);
594			return(1);
595		}
596		break;
597	case PAX_REG:
598	case PAX_CTG:
599	default:
600		break;
601	}
602
603	/*
604	 * check file name len, remember extra char for dirs (the / at the end)
605	 */
606	len = arcn->nlen;
607	if (arcn->type == PAX_DIR)
608		++len;
609	if (len >= sizeof(hd->name)) {
610		tty_warn(1, "File name too long for tar %s", arcn->name);
611		return(1);
612	}
613
614	/*
615	 * copy the data out of the ARCHD into the tar header based on the type
616	 * of the file. Remember many tar readers want the unused fields to be
617	 * padded with zero. We set the linkflag field (type), the linkname
618	 * (or zero if not used),the size, and set the padding (if any) to be
619	 * added after the file data (0 for all other types, as they only have
620	 * a header)
621	 */
622	memset(hdblk, 0, sizeof(hdblk));
623	hd = (HD_TAR *)hdblk;
624	strlcpy(hd->name, arcn->name, sizeof(hd->name));
625	arcn->pad = 0;
626
627	if (arcn->type == PAX_DIR) {
628		/*
629		 * directories are the same as files, except have a filename
630		 * that ends with a /, we add the slash here. No data follows,
631		 * dirs, so no pad.
632		 */
633		hd->linkflag = AREGTYPE;
634		hd->name[len-1] = '/';
635		if (ul_oct((u_long)0L, hd->size, sizeof(hd->size), 1))
636			goto out;
637	} else if (arcn->type == PAX_SLK) {
638		/*
639		 * no data follows this file, so no pad
640		 */
641		hd->linkflag = SYMTYPE;
642		strlcpy(hd->linkname, arcn->ln_name, sizeof(hd->linkname));
643		if (ul_oct((u_long)0L, hd->size, sizeof(hd->size), 1))
644			goto out;
645	} else if ((arcn->type == PAX_HLK) || (arcn->type == PAX_HRG)) {
646		/*
647		 * no data follows this file, so no pad
648		 */
649		hd->linkflag = LNKTYPE;
650		strlcpy(hd->linkname, arcn->ln_name, sizeof(hd->linkname));
651		if (ul_oct((u_long)0L, hd->size, sizeof(hd->size), 1))
652			goto out;
653	} else {
654		/*
655		 * data follows this file, so set the pad
656		 */
657		hd->linkflag = AREGTYPE;
658		if (OFFT_OCT(arcn->sb.st_size, hd->size, sizeof(hd->size), 1)) {
659			tty_warn(1,"File is too large for tar %s",
660			    arcn->org_name);
661			return(1);
662		}
663		arcn->pad = TAR_PAD(arcn->sb.st_size);
664	}
665
666	/*
667	 * copy those fields that are independent of the type
668	 */
669	if (ul_oct((u_long)arcn->sb.st_mode, hd->mode, sizeof(hd->mode), 0) ||
670	    ul_oct((u_long)arcn->sb.st_uid, hd->uid, sizeof(hd->uid), 0) ||
671	    ul_oct((u_long)arcn->sb.st_gid, hd->gid, sizeof(hd->gid), 0) ||
672	    ul_oct((u_long)arcn->sb.st_mtime, hd->mtime, sizeof(hd->mtime), 1))
673		goto out;
674
675	/*
676	 * calculate and add the checksum, then write the header. A return of
677	 * 0 tells the caller to now write the file data, 1 says no data needs
678	 * to be written
679	 */
680	if (ul_oct(tar_chksm(hdblk, sizeof(HD_TAR)), hd->chksum,
681	    sizeof(hd->chksum), 3))
682		goto out;			/* XXX Something's wrong here
683						 * because a zero-byte file can
684						 * cause this to be done and
685						 * yet the resulting warning
686						 * seems incorrect */
687
688	if (wr_rdbuf(hdblk, sizeof(HD_TAR)) < 0)
689		return(-1);
690	if (wr_skip((off_t)(BLKMULT - sizeof(HD_TAR))) < 0)
691		return(-1);
692	if ((arcn->type == PAX_CTG) || (arcn->type == PAX_REG))
693		return(0);
694	return(1);
695
696    out:
697	/*
698	 * header field is out of range
699	 */
700	tty_warn(1, "Tar header field is too small for %s", arcn->org_name);
701	return(1);
702}
703
704/*
705 * Routines for POSIX ustar
706 */
707
708/*
709 * ustar_strd()
710 *	initialization for ustar read
711 * Return:
712 *	0 if ok, -1 otherwise
713 */
714
715int
716ustar_strd(void)
717{
718	return(0);
719}
720
721/*
722 * ustar_stwr()
723 *	initialization for ustar write
724 * Return:
725 *	0 if ok, -1 otherwise
726 */
727
728int
729ustar_stwr(void)
730{
731	return(0);
732}
733
734/*
735 * ustar_id()
736 *	determine if a block given to us is a valid ustar header. We have to
737 *	be on the lookout for those pesky blocks of all zero's
738 * Return:
739 *	0 if a ustar header, -1 otherwise
740 */
741
742int
743ustar_id(char *blk, int size)
744{
745	HD_USTAR *hd;
746
747	if (size < BLKMULT)
748		return(-1);
749	hd = (HD_USTAR *)blk;
750
751	/*
752	 * check for block of zero's first, a simple and fast test then check
753	 * ustar magic cookie. We should use TMAGLEN, but some USTAR archive
754	 * programs are fouled up and create archives missing the \0. Last we
755	 * check the checksum. If ok we have to assume it is a valid header.
756	 */
757	if (hd->name[0] == '\0')
758		return(-1);
759	if (strncmp(hd->magic, TMAGIC, TMAGLEN - 1) != 0)
760		return(-1);
761	/* This is GNU tar */
762	if (strncmp(hd->magic, "ustar  ", 8) == 0 && !is_gnutar &&
763	    !seen_gnu_warning) {
764		seen_gnu_warning = 1;
765		tty_warn(0,
766		    "Trying to read GNU tar archive with extensions off");
767	}
768	return check_sum(hd->chksum, sizeof(hd->chksum), blk, BLKMULT, 0);
769}
770
771/*
772 * ustar_rd()
773 *	extract the values out of block already determined to be a ustar header.
774 *	store the values in the ARCHD parameter.
775 * Return:
776 *	0
777 */
778
779int
780ustar_rd(ARCHD *arcn, char *buf)
781{
782	HD_USTAR *hd;
783	char *dest;
784	int cnt;
785	dev_t devmajor;
786	dev_t devminor;
787
788	/*
789	 * we only get proper sized buffers
790	 */
791	if (ustar_id(buf, BLKMULT) < 0)
792		return(-1);
793
794	memset(arcn, 0, sizeof(*arcn));
795	arcn->org_name = arcn->name;
796	arcn->pat = NULL;
797	arcn->sb.st_nlink = 1;
798	hd = (HD_USTAR *)buf;
799
800	/*
801	 * see if the filename is split into two parts. if, so joint the parts.
802	 * we copy the prefix first and add a / between the prefix and name.
803	 */
804	dest = arcn->name;
805	if (*(hd->prefix) != '\0') {
806		cnt = strlcpy(arcn->name, hd->prefix, sizeof(arcn->name));
807		dest += cnt;
808		*dest++ = '/';
809		cnt++;
810	} else {
811		cnt = 0;
812	}
813
814	if (hd->typeflag != LONGLINKTYPE && hd->typeflag != LONGNAMETYPE) {
815		arcn->nlen = expandname(dest, sizeof(arcn->name) - cnt,
816		    &gnu_name_string, hd->name, sizeof(hd->name)) + cnt;
817		arcn->ln_nlen = expandname(arcn->ln_name,
818		    sizeof(arcn->ln_name), &gnu_link_string, hd->linkname,
819		    sizeof(hd->linkname));
820	}
821
822	/*
823	 * follow the spec to the letter. we should only have mode bits, strip
824	 * off all other crud we may be passed.
825	 */
826	arcn->sb.st_mode = (mode_t)(asc_ul(hd->mode, sizeof(hd->mode), OCT) &
827	    0xfff);
828	arcn->sb.st_size = (off_t)ASC_OFFT(hd->size, sizeof(hd->size), OCT);
829	arcn->sb.st_mtime = (time_t)asc_ul(hd->mtime, sizeof(hd->mtime), OCT);
830	arcn->sb.st_ctime = arcn->sb.st_atime = arcn->sb.st_mtime;
831
832	/*
833	 * If we can find the ascii names for gname and uname in the password
834	 * and group files we will use the uid's and gid they bind. Otherwise
835	 * we use the uid and gid values stored in the header. (This is what
836	 * the posix spec wants).
837	 */
838	hd->gname[sizeof(hd->gname) - 1] = '\0';
839	if (gid_from_group(hd->gname, &(arcn->sb.st_gid)) < 0)
840		arcn->sb.st_gid = (gid_t)asc_ul(hd->gid, sizeof(hd->gid), OCT);
841	hd->uname[sizeof(hd->uname) - 1] = '\0';
842	if (uid_from_user(hd->uname, &(arcn->sb.st_uid)) < 0)
843		arcn->sb.st_uid = (uid_t)asc_ul(hd->uid, sizeof(hd->uid), OCT);
844
845	/*
846	 * set the defaults, these may be changed depending on the file type
847	 */
848	arcn->pad = 0;
849	arcn->skip = 0;
850	arcn->sb.st_rdev = (dev_t)0;
851
852	/*
853	 * set the mode and PAX type according to the typeflag in the header
854	 */
855	switch(hd->typeflag) {
856	case FIFOTYPE:
857		arcn->type = PAX_FIF;
858		arcn->sb.st_mode |= S_IFIFO;
859		break;
860	case DIRTYPE:
861		arcn->type = PAX_DIR;
862		arcn->sb.st_mode |= S_IFDIR;
863		arcn->sb.st_nlink = 2;
864
865		/*
866		 * Some programs that create ustar archives append a '/'
867		 * to the pathname for directories. This clearly violates
868		 * ustar specs, but we will silently strip it off anyway.
869		 */
870		if (arcn->name[arcn->nlen - 1] == '/')
871			arcn->name[--arcn->nlen] = '\0';
872		break;
873	case BLKTYPE:
874	case CHRTYPE:
875		/*
876		 * this type requires the rdev field to be set.
877		 */
878		if (hd->typeflag == BLKTYPE) {
879			arcn->type = PAX_BLK;
880			arcn->sb.st_mode |= S_IFBLK;
881		} else {
882			arcn->type = PAX_CHR;
883			arcn->sb.st_mode |= S_IFCHR;
884		}
885		devmajor = (dev_t)asc_ul(hd->devmajor,sizeof(hd->devmajor),OCT);
886		devminor = (dev_t)asc_ul(hd->devminor,sizeof(hd->devminor),OCT);
887		arcn->sb.st_rdev = TODEV(devmajor, devminor);
888		break;
889	case SYMTYPE:
890	case LNKTYPE:
891		if (hd->typeflag == SYMTYPE) {
892			arcn->type = PAX_SLK;
893			arcn->sb.st_mode |= S_IFLNK;
894		} else {
895			arcn->type = PAX_HLK;
896			/*
897			 * so printing looks better
898			 */
899			arcn->sb.st_mode |= S_IFREG;
900			arcn->sb.st_nlink = 2;
901		}
902		break;
903	case LONGLINKTYPE:
904		if (is_gnutar)
905			arcn->type = PAX_GLL;
906		/* FALLTHROUGH */
907	case LONGNAMETYPE:
908		if (is_gnutar) {
909			/*
910			 * GNU long link/file; we tag these here and let the
911			 * pax internals deal with it -- too ugly otherwise.
912			 */
913			if (hd->typeflag != LONGLINKTYPE)
914				arcn->type = PAX_GLF;
915			arcn->pad = TAR_PAD(arcn->sb.st_size);
916			arcn->skip = arcn->sb.st_size;
917		} else {
918			tty_warn(1, "GNU Long %s found in posix ustar archive.",
919			    hd->typeflag == LONGLINKTYPE ? "Link" : "File");
920		}
921		break;
922	case CONTTYPE:
923	case AREGTYPE:
924	case REGTYPE:
925	default:
926		/*
927		 * these types have file data that follows. Set the skip and
928		 * pad fields.
929		 */
930		arcn->type = PAX_REG;
931		arcn->pad = TAR_PAD(arcn->sb.st_size);
932		arcn->skip = arcn->sb.st_size;
933		arcn->sb.st_mode |= S_IFREG;
934		break;
935	}
936	return(0);
937}
938
939static int
940expandname(char *buf, size_t len, char **gnu_name, const char *name,
941    size_t nlen)
942{
943	if (*gnu_name) {
944		len = strlcpy(buf, *gnu_name, len);
945		free(*gnu_name);
946		*gnu_name = NULL;
947	} else {
948		if (len > ++nlen)
949			len = nlen;
950		len = strlcpy(buf, name, len);
951	}
952	return len;
953}
954
955static void
956longlink(ARCHD *arcn)
957{
958	ARCHD larc;
959
960	memset(&larc, 0, sizeof(larc));
961
962	switch (arcn->type) {
963	case PAX_SLK:
964	case PAX_HRG:
965	case PAX_HLK:
966		larc.type = PAX_GLL;
967		larc.ln_nlen = strlcpy(larc.ln_name, "././@LongLink",
968		    sizeof(larc.ln_name));
969		gnu_hack_string = arcn->ln_name;
970		gnu_hack_len = arcn->ln_nlen + 1;
971		break;
972	default:
973		larc.nlen = strlcpy(larc.name, "././@LongLink",
974		    sizeof(larc.name));
975		gnu_hack_string = arcn->name;
976		gnu_hack_len = arcn->nlen + 1;
977		larc.type = PAX_GLF;
978	}
979	/*
980	 * We need a longlink now.
981	 */
982	ustar_wr(&larc);
983}
984
985/*
986 * ustar_wr()
987 *	write a ustar header for the file specified in the ARCHD to the archive
988 *	Have to check for file types that cannot be stored and file names that
989 *	are too long. Be careful of the term (last arg) to ul_oct, we only use
990 *	'\0' for the termination character (this is different than picky tar)
991 *	ASSUMED: space after header in header block is zero filled
992 * Return:
993 *	0 if file has data to be written after the header, 1 if file has NO
994 *	data to write after the header, -1 if archive write failed
995 */
996
997int
998ustar_wr(ARCHD *arcn)
999{
1000	HD_USTAR *hd;
1001	char *pt;
1002	char hdblk[sizeof(HD_USTAR)];
1003	const char *user, *group;
1004
1005	/*
1006	 * check for those file system types ustar cannot store
1007	 */
1008	if (arcn->type == PAX_SCK) {
1009		if (!is_gnutar)
1010			tty_warn(1, "Ustar cannot archive a socket %s",
1011			    arcn->org_name);
1012		return(1);
1013	}
1014
1015	/*
1016	 * check the length of the linkname
1017	 */
1018	if (((arcn->type == PAX_SLK) || (arcn->type == PAX_HLK) ||
1019	    (arcn->type == PAX_HRG)) &&
1020	    (arcn->ln_nlen >= sizeof(hd->linkname))){
1021		if (is_gnutar) {
1022			longlink(arcn);
1023		} else {
1024			tty_warn(1, "Link name too long for ustar %s",
1025			    arcn->ln_name);
1026			return(1);
1027		}
1028	}
1029
1030	/*
1031	 * split the path name into prefix and name fields (if needed). if
1032	 * pt != arcn->name, the name has to be split
1033	 */
1034	if ((pt = name_split(arcn->name, arcn->nlen)) == NULL) {
1035		if (is_gnutar) {
1036			longlink(arcn);
1037			pt = arcn->name;
1038		} else {
1039			tty_warn(1, "File name too long for ustar %s",
1040			    arcn->name);
1041			return(1);
1042		}
1043	}
1044
1045	/*
1046	 * zero out the header so we don't have to worry about zero fill below
1047	 */
1048	memset(hdblk, 0, sizeof(hdblk));
1049	hd = (HD_USTAR *)hdblk;
1050	arcn->pad = 0L;
1051
1052	/*
1053	 * split the name, or zero out the prefix
1054	 */
1055	if (pt != arcn->name) {
1056		/*
1057		 * name was split, pt points at the / where the split is to
1058		 * occur, we remove the / and copy the first part to the prefix
1059		 */
1060		*pt = '\0';
1061		strlcpy(hd->prefix, arcn->name, sizeof(hd->prefix));
1062		*pt++ = '/';
1063	}
1064
1065	/*
1066	 * copy the name part. this may be the whole path or the part after
1067	 * the prefix
1068	 */
1069	strlcpy(hd->name, pt, sizeof(hd->name));
1070
1071	/*
1072	 * set the fields in the header that are type dependent
1073	 */
1074	switch(arcn->type) {
1075	case PAX_DIR:
1076		hd->typeflag = DIRTYPE;
1077		if (ul_oct((u_long)0L, hd->size, sizeof(hd->size), 3))
1078			goto out;
1079		break;
1080	case PAX_CHR:
1081	case PAX_BLK:
1082		if (arcn->type == PAX_CHR)
1083			hd->typeflag = CHRTYPE;
1084		else
1085			hd->typeflag = BLKTYPE;
1086		if (ul_oct((u_long)MAJOR(arcn->sb.st_rdev), hd->devmajor,
1087		   sizeof(hd->devmajor), 3) ||
1088		   ul_oct((u_long)MINOR(arcn->sb.st_rdev), hd->devminor,
1089		   sizeof(hd->devminor), 3) ||
1090		   ul_oct((u_long)0L, hd->size, sizeof(hd->size), 3))
1091			goto out;
1092		break;
1093	case PAX_FIF:
1094		hd->typeflag = FIFOTYPE;
1095		if (ul_oct((u_long)0L, hd->size, sizeof(hd->size), 3))
1096			goto out;
1097		break;
1098	case PAX_GLL:
1099	case PAX_SLK:
1100	case PAX_HLK:
1101	case PAX_HRG:
1102		if (arcn->type == PAX_SLK)
1103			hd->typeflag = SYMTYPE;
1104		else if (arcn->type == PAX_GLL)
1105			hd->typeflag = LONGLINKTYPE;
1106		else
1107			hd->typeflag = LNKTYPE;
1108		strlcpy(hd->linkname, arcn->ln_name, sizeof(hd->linkname));
1109		if (ul_oct((u_long)gnu_hack_len, hd->size,
1110		    sizeof(hd->size), 3))
1111			goto out;
1112		break;
1113	case PAX_GLF:
1114	case PAX_REG:
1115	case PAX_CTG:
1116	default:
1117		/*
1118		 * file data with this type, set the padding
1119		 */
1120		if (arcn->type == PAX_GLF) {
1121			hd->typeflag = LONGNAMETYPE;
1122			arcn->pad = TAR_PAD(gnu_hack_len);
1123			if (OFFT_OCT((u_long)gnu_hack_len, hd->size,
1124			    sizeof(hd->size), 3)) {
1125				tty_warn(1,"File is too long for ustar %s",
1126				    arcn->org_name);
1127				return(1);
1128			}
1129		} else {
1130			if (arcn->type == PAX_CTG)
1131				hd->typeflag = CONTTYPE;
1132			else
1133				hd->typeflag = REGTYPE;
1134			arcn->pad = TAR_PAD(arcn->sb.st_size);
1135			if (OFFT_OCT(arcn->sb.st_size, hd->size,
1136			    sizeof(hd->size), 3)) {
1137				tty_warn(1,"File is too long for ustar %s",
1138				    arcn->org_name);
1139				return(1);
1140			}
1141		}
1142		break;
1143	}
1144
1145	strncpy(hd->magic, TMAGIC, TMAGLEN);
1146	if (is_gnutar)
1147		hd->magic[TMAGLEN - 1] = hd->magic[TMAGLEN] = ' ';
1148	else
1149		strncpy(hd->version, TVERSION, TVERSLEN);
1150
1151	/*
1152	 * set the remaining fields. Some versions want all 16 bits of mode
1153	 * we better humor them (they really do not meet spec though)....
1154	 */
1155	if (ul_oct((u_long)arcn->sb.st_mode, hd->mode, sizeof(hd->mode), 3) ||
1156	    ul_oct((u_long)arcn->sb.st_uid, hd->uid, sizeof(hd->uid), 3)  ||
1157	    ul_oct((u_long)arcn->sb.st_gid, hd->gid, sizeof(hd->gid), 3) ||
1158	    ul_oct((u_long)arcn->sb.st_mtime,hd->mtime,sizeof(hd->mtime),3))
1159		goto out;
1160	user = user_from_uid(arcn->sb.st_uid, 1);
1161	group = group_from_gid(arcn->sb.st_gid, 1);
1162	strncpy(hd->uname, user ? user : "", sizeof(hd->uname));
1163	strncpy(hd->gname, group ? group : "", sizeof(hd->gname));
1164
1165	/*
1166	 * calculate and store the checksum write the header to the archive
1167	 * return 0 tells the caller to now write the file data, 1 says no data
1168	 * needs to be written
1169	 */
1170	if (ul_oct(tar_chksm(hdblk, sizeof(HD_USTAR)), hd->chksum,
1171	   sizeof(hd->chksum), 3))
1172		goto out;
1173	if (wr_rdbuf(hdblk, sizeof(HD_USTAR)) < 0)
1174		return(-1);
1175	if (wr_skip((off_t)(BLKMULT - sizeof(HD_USTAR))) < 0)
1176		return(-1);
1177	if (gnu_hack_string) {
1178		int res = wr_rdbuf(gnu_hack_string, gnu_hack_len);
1179		int pad = gnu_hack_len;
1180		gnu_hack_string = NULL;
1181		gnu_hack_len = 0;
1182		if (res < 0)
1183			return(-1);
1184		if (wr_skip((off_t)(BLKMULT - (pad % BLKMULT))) < 0)
1185			return(-1);
1186	}
1187	if ((arcn->type == PAX_CTG) || (arcn->type == PAX_REG))
1188		return(0);
1189	return(1);
1190
1191    out:
1192	/*
1193	 * header field is out of range
1194	 */
1195	tty_warn(1, "Ustar header field is too small for %s", arcn->org_name);
1196	return(1);
1197}
1198
1199/*
1200 * name_split()
1201 *	see if the name has to be split for storage in a ustar header. We try
1202 *	to fit the entire name in the name field without splitting if we can.
1203 *	The split point is always at a /
1204 * Return
1205 *	character pointer to split point (always the / that is to be removed
1206 *	if the split is not needed, the points is set to the start of the file
1207 *	name (it would violate the spec to split there). A NULL is returned if
1208 *	the file name is too long
1209 */
1210
1211static char *
1212name_split(char *name, int len)
1213{
1214	char *start;
1215
1216	/*
1217	 * check to see if the file name is small enough to fit in the name
1218	 * field. if so just return a pointer to the name.
1219	 */
1220	if (len < TNMSZ)
1221		return(name);
1222	if (len > (TPFSZ + TNMSZ))
1223		return(NULL);
1224
1225	/*
1226	 * we start looking at the biggest sized piece that fits in the name
1227	 * field. We walk forward looking for a slash to split at. The idea is
1228	 * to find the biggest piece to fit in the name field (or the smallest
1229	 * prefix we can find) (the -1 is correct the biggest piece would
1230	 * include the slash between the two parts that gets thrown away)
1231	 */
1232	start = name + len - TNMSZ;
1233	while ((*start != '\0') && (*start != '/'))
1234		++start;
1235
1236	/*
1237	 * if we hit the end of the string, this name cannot be split, so we
1238	 * cannot store this file.
1239	 */
1240	if (*start == '\0')
1241		return(NULL);
1242	len = start - name;
1243
1244	/*
1245	 * NOTE: /str where the length of str == TNMSZ cannot be stored under
1246	 * the p1003.1-1990 spec for ustar. We could force a prefix of / and
1247	 * the file would then expand on extract to //str. The len == 0 below
1248	 * makes this special case follow the spec to the letter.
1249	 */
1250	if ((len >= TPFSZ) || (len == 0))
1251		return(NULL);
1252
1253	/*
1254	 * ok have a split point, return it to the caller
1255	 */
1256	return(start);
1257}
1258
1259/*
1260 * convert a glob into a RE, and add it to the list.  we convert to
1261 * four different RE's (because we're using BRE's and can't use |
1262 * alternation :-() with this padding:
1263 *	.*\/ and $
1264 *	.*\/ and \/.*
1265 *	^ and $
1266 *	^ and \/.*
1267 */
1268static int
1269tar_gnutar_exclude_one(const char *line, size_t len)
1270{
1271	/* 2 * buffer len + nul */
1272	char sbuf[MAXPATHLEN * 2 + 1];
1273	/* + / + // + .*""/\/ + \/.* */
1274	char rabuf[MAXPATHLEN * 2 + 1 + 1 + 2 + 4 + 4];
1275	int i, j;
1276
1277	if (line[len - 1] == '\n')
1278		len--;
1279	strncpy(sbuf, ".*" "\\/", j = 4);
1280	for (i = 0; i < len; i++) {
1281		/*
1282		 * convert glob to regexp, escaping everything
1283		 */
1284		if (line[i] == '*')
1285			sbuf[j++] = '.';
1286		else if (line[i] == '?') {
1287			sbuf[j++] = '.';
1288			continue;
1289		} else if (!isalnum(line[i]) && !isblank(line[i]))
1290			sbuf[j++] = '\\';
1291		sbuf[j++] = line[i];
1292	}
1293	/* don't need the .*\/ ones if we start with /, i guess */
1294	if (line[0] != '/') {
1295		(void)snprintf(rabuf, sizeof rabuf, "/.*\\/%s$//", sbuf);
1296		if (rep_add(rabuf) < 0)
1297			return (-1);
1298		(void)snprintf(rabuf, sizeof rabuf, "/.*\\/%s\\/.*//", sbuf);
1299		if (rep_add(rabuf) < 0)
1300			return (-1);
1301	}
1302
1303	(void)snprintf(rabuf, sizeof rabuf, "/^%s$//", sbuf);
1304	if (rep_add(rabuf) < 0)
1305		return (-1);
1306	(void)snprintf(rabuf, sizeof rabuf, "/^%s\\/.*//", sbuf);
1307	if (rep_add(rabuf) < 0)
1308		return (-1);
1309
1310	return (0);
1311}
1312
1313/*
1314 * deal with GNU tar -X/--exclude-from & --exclude switchs.  basically,
1315 * we go through each line of the file, building a string from the "glob"
1316 * lines in the file into RE lines, of the form `/^RE$//', which we pass
1317 * to rep_add(), which will add a empty replacement (exclusion), for the
1318 * named files.
1319 */
1320int
1321tar_gnutar_minus_minus_exclude(path)
1322	const char *path;
1323{
1324	size_t	len = strlen(path);
1325
1326	if (len > MAXPATHLEN)
1327		tty_warn(0, "pathname too long: %s", path);
1328
1329	return (tar_gnutar_exclude_one(path, len));
1330}
1331
1332int
1333tar_gnutar_X_compat(path)
1334	const char *path;
1335{
1336	char *line;
1337	FILE *fp;
1338	int lineno = 0;
1339	size_t len;
1340
1341	fp = fopen(path, "r");
1342	if (fp == NULL) {
1343		tty_warn(1, "cannot open %s: %s", path,
1344		    strerror(errno));
1345		return(-1);
1346	}
1347
1348	while ((line = fgetln(fp, &len))) {
1349		lineno++;
1350		if (len > MAXPATHLEN) {
1351			tty_warn(0, "pathname too long, line %d of %s",
1352			    lineno, path);
1353		}
1354		if (tar_gnutar_exclude_one(line, len))
1355			return (-1);
1356	}
1357	return (0);
1358}
1359