xref: /freebsd/contrib/libarchive/tar/util.c (revision 3fc36ee018bb836bd1796067cf4ef8683f166ebc)
1 /*-
2  * Copyright (c) 2003-2007 Tim Kientzle
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
15  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17  * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
18  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24  */
25 
26 #include "bsdtar_platform.h"
27 __FBSDID("$FreeBSD$");
28 
29 #ifdef HAVE_SYS_STAT_H
30 #include <sys/stat.h>
31 #endif
32 #ifdef HAVE_SYS_TYPES_H
33 #include <sys/types.h>  /* Linux doesn't define mode_t, etc. in sys/stat.h. */
34 #endif
35 #include <ctype.h>
36 #ifdef HAVE_ERRNO_H
37 #include <errno.h>
38 #endif
39 #ifdef HAVE_IO_H
40 #include <io.h>
41 #endif
42 #ifdef HAVE_STDARG_H
43 #include <stdarg.h>
44 #endif
45 #ifdef HAVE_STDINT_H
46 #include <stdint.h>
47 #endif
48 #include <stdio.h>
49 #ifdef HAVE_STDLIB_H
50 #include <stdlib.h>
51 #endif
52 #ifdef HAVE_STRING_H
53 #include <string.h>
54 #endif
55 #ifdef HAVE_WCTYPE_H
56 #include <wctype.h>
57 #else
58 /* If we don't have wctype, we need to hack up some version of iswprint(). */
59 #define	iswprint isprint
60 #endif
61 
62 #include "bsdtar.h"
63 #include "err.h"
64 #include "passphrase.h"
65 
66 static size_t	bsdtar_expand_char(char *, size_t, char);
67 static const char *strip_components(const char *path, int elements);
68 
69 #if defined(_WIN32) && !defined(__CYGWIN__)
70 #define	read _read
71 #endif
72 
73 /* TODO:  Hack up a version of mbtowc for platforms with no wide
74  * character support at all.  I think the following might suffice,
75  * but it needs careful testing.
76  * #if !HAVE_MBTOWC
77  * #define	mbtowc(wcp, p, n) ((*wcp = *p), 1)
78  * #endif
79  */
80 
81 /*
82  * Print a string, taking care with any non-printable characters.
83  *
84  * Note that we use a stack-allocated buffer to receive the formatted
85  * string if we can.  This is partly performance (avoiding a call to
86  * malloc()), partly out of expedience (we have to call vsnprintf()
87  * before malloc() anyway to find out how big a buffer we need; we may
88  * as well point that first call at a small local buffer in case it
89  * works), but mostly for safety (so we can use this to print messages
90  * about out-of-memory conditions).
91  */
92 
93 void
94 safe_fprintf(FILE *f, const char *fmt, ...)
95 {
96 	char fmtbuff_stack[256]; /* Place to format the printf() string. */
97 	char outbuff[256]; /* Buffer for outgoing characters. */
98 	char *fmtbuff_heap; /* If fmtbuff_stack is too small, we use malloc */
99 	char *fmtbuff;  /* Pointer to fmtbuff_stack or fmtbuff_heap. */
100 	int fmtbuff_length;
101 	int length, n;
102 	va_list ap;
103 	const char *p;
104 	unsigned i;
105 	wchar_t wc;
106 	char try_wc;
107 
108 	/* Use a stack-allocated buffer if we can, for speed and safety. */
109 	fmtbuff_heap = NULL;
110 	fmtbuff_length = sizeof(fmtbuff_stack);
111 	fmtbuff = fmtbuff_stack;
112 
113 	/* Try formatting into the stack buffer. */
114 	va_start(ap, fmt);
115 	length = vsnprintf(fmtbuff, fmtbuff_length, fmt, ap);
116 	va_end(ap);
117 
118 	/* If the result was too large, allocate a buffer on the heap. */
119 	while (length < 0 || length >= fmtbuff_length) {
120 		if (length >= fmtbuff_length)
121 			fmtbuff_length = length+1;
122 		else if (fmtbuff_length < 8192)
123 			fmtbuff_length *= 2;
124 		else if (fmtbuff_length < 1000000)
125 			fmtbuff_length += fmtbuff_length / 4;
126 		else {
127 			length = fmtbuff_length;
128 			fmtbuff_heap[length-1] = '\0';
129 			break;
130 		}
131 		free(fmtbuff_heap);
132 		fmtbuff_heap = malloc(fmtbuff_length);
133 
134 		/* Reformat the result into the heap buffer if we can. */
135 		if (fmtbuff_heap != NULL) {
136 			fmtbuff = fmtbuff_heap;
137 			va_start(ap, fmt);
138 			length = vsnprintf(fmtbuff, fmtbuff_length, fmt, ap);
139 			va_end(ap);
140 		} else {
141 			/* Leave fmtbuff pointing to the truncated
142 			 * string in fmtbuff_stack. */
143 			length = sizeof(fmtbuff_stack) - 1;
144 			break;
145 		}
146 	}
147 
148 	/* Note: mbrtowc() has a cleaner API, but mbtowc() seems a bit
149 	 * more portable, so we use that here instead. */
150 	if (mbtowc(NULL, NULL, 1) == -1) { /* Reset the shift state. */
151 		/* mbtowc() should never fail in practice, but
152 		 * handle the theoretical error anyway. */
153 		free(fmtbuff_heap);
154 		return;
155 	}
156 
157 	/* Write data, expanding unprintable characters. */
158 	p = fmtbuff;
159 	i = 0;
160 	try_wc = 1;
161 	while (*p != '\0') {
162 
163 		/* Convert to wide char, test if the wide
164 		 * char is printable in the current locale. */
165 		if (try_wc && (n = mbtowc(&wc, p, length)) != -1) {
166 			length -= n;
167 			if (iswprint(wc) && wc != L'\\') {
168 				/* Printable, copy the bytes through. */
169 				while (n-- > 0)
170 					outbuff[i++] = *p++;
171 			} else {
172 				/* Not printable, format the bytes. */
173 				while (n-- > 0)
174 					i += (unsigned)bsdtar_expand_char(
175 					    outbuff, i, *p++);
176 			}
177 		} else {
178 			/* After any conversion failure, don't bother
179 			 * trying to convert the rest. */
180 			i += (unsigned)bsdtar_expand_char(outbuff, i, *p++);
181 			try_wc = 0;
182 		}
183 
184 		/* If our output buffer is full, dump it and keep going. */
185 		if (i > (sizeof(outbuff) - 128)) {
186 			outbuff[i] = '\0';
187 			fprintf(f, "%s", outbuff);
188 			i = 0;
189 		}
190 	}
191 	outbuff[i] = '\0';
192 	fprintf(f, "%s", outbuff);
193 
194 	/* If we allocated a heap-based formatting buffer, free it now. */
195 	free(fmtbuff_heap);
196 }
197 
198 /*
199  * Render an arbitrary sequence of bytes into printable ASCII characters.
200  */
201 static size_t
202 bsdtar_expand_char(char *buff, size_t offset, char c)
203 {
204 	size_t i = offset;
205 
206 	if (isprint((unsigned char)c) && c != '\\')
207 		buff[i++] = c;
208 	else {
209 		buff[i++] = '\\';
210 		switch (c) {
211 		case '\a': buff[i++] = 'a'; break;
212 		case '\b': buff[i++] = 'b'; break;
213 		case '\f': buff[i++] = 'f'; break;
214 		case '\n': buff[i++] = 'n'; break;
215 #if '\r' != '\n'
216 		/* On some platforms, \n and \r are the same. */
217 		case '\r': buff[i++] = 'r'; break;
218 #endif
219 		case '\t': buff[i++] = 't'; break;
220 		case '\v': buff[i++] = 'v'; break;
221 		case '\\': buff[i++] = '\\'; break;
222 		default:
223 			sprintf(buff + i, "%03o", 0xFF & (int)c);
224 			i += 3;
225 		}
226 	}
227 
228 	return (i - offset);
229 }
230 
231 int
232 yes(const char *fmt, ...)
233 {
234 	char buff[32];
235 	char *p;
236 	ssize_t l;
237 
238 	va_list ap;
239 	va_start(ap, fmt);
240 	vfprintf(stderr, fmt, ap);
241 	va_end(ap);
242 	fprintf(stderr, " (y/N)? ");
243 	fflush(stderr);
244 
245 	l = read(2, buff, sizeof(buff) - 1);
246 	if (l < 0) {
247 	  fprintf(stderr, "Keyboard read failed\n");
248 	  exit(1);
249 	}
250 	if (l == 0)
251 		return (0);
252 	buff[l] = 0;
253 
254 	for (p = buff; *p != '\0'; p++) {
255 		if (isspace((unsigned char)*p))
256 			continue;
257 		switch(*p) {
258 		case 'y': case 'Y':
259 			return (1);
260 		case 'n': case 'N':
261 			return (0);
262 		default:
263 			return (0);
264 		}
265 	}
266 
267 	return (0);
268 }
269 
270 /*-
271  * The logic here for -C <dir> attempts to avoid
272  * chdir() as long as possible.  For example:
273  * "-C /foo -C /bar file"          needs chdir("/bar") but not chdir("/foo")
274  * "-C /foo -C bar file"           needs chdir("/foo/bar")
275  * "-C /foo -C bar /file1"         does not need chdir()
276  * "-C /foo -C bar /file1 file2"   needs chdir("/foo/bar") before file2
277  *
278  * The only correct way to handle this is to record a "pending" chdir
279  * request and combine multiple requests intelligently until we
280  * need to process a non-absolute file.  set_chdir() adds the new dir
281  * to the pending list; do_chdir() actually executes any pending chdir.
282  *
283  * This way, programs that build tar command lines don't have to worry
284  * about -C with non-existent directories; such requests will only
285  * fail if the directory must be accessed.
286  *
287  */
288 void
289 set_chdir(struct bsdtar *bsdtar, const char *newdir)
290 {
291 #if defined(_WIN32) && !defined(__CYGWIN__)
292 	if (newdir[0] == '/' || newdir[0] == '\\' ||
293 	    /* Detect this type, for example, "C:\" or "C:/" */
294 	    (((newdir[0] >= 'a' && newdir[0] <= 'z') ||
295 	      (newdir[0] >= 'A' && newdir[0] <= 'Z')) &&
296 	    newdir[1] == ':' && (newdir[2] == '/' || newdir[2] == '\\'))) {
297 #else
298 	if (newdir[0] == '/') {
299 #endif
300 		/* The -C /foo -C /bar case; dump first one. */
301 		free(bsdtar->pending_chdir);
302 		bsdtar->pending_chdir = NULL;
303 	}
304 	if (bsdtar->pending_chdir == NULL)
305 		/* Easy case: no previously-saved dir. */
306 		bsdtar->pending_chdir = strdup(newdir);
307 	else {
308 		/* The -C /foo -C bar case; concatenate */
309 		char *old_pending = bsdtar->pending_chdir;
310 		size_t old_len = strlen(old_pending);
311 		bsdtar->pending_chdir = malloc(old_len + strlen(newdir) + 2);
312 		if (old_pending[old_len - 1] == '/')
313 			old_pending[old_len - 1] = '\0';
314 		if (bsdtar->pending_chdir != NULL)
315 			sprintf(bsdtar->pending_chdir, "%s/%s",
316 			    old_pending, newdir);
317 		free(old_pending);
318 	}
319 	if (bsdtar->pending_chdir == NULL)
320 		lafe_errc(1, errno, "No memory");
321 }
322 
323 void
324 do_chdir(struct bsdtar *bsdtar)
325 {
326 	if (bsdtar->pending_chdir == NULL)
327 		return;
328 
329 	if (chdir(bsdtar->pending_chdir) != 0) {
330 		lafe_errc(1, 0, "could not chdir to '%s'\n",
331 		    bsdtar->pending_chdir);
332 	}
333 	free(bsdtar->pending_chdir);
334 	bsdtar->pending_chdir = NULL;
335 }
336 
337 static const char *
338 strip_components(const char *p, int elements)
339 {
340 	/* Skip as many elements as necessary. */
341 	while (elements > 0) {
342 		switch (*p++) {
343 		case '/':
344 #if defined(_WIN32) && !defined(__CYGWIN__)
345 		case '\\': /* Support \ path sep on Windows ONLY. */
346 #endif
347 			elements--;
348 			break;
349 		case '\0':
350 			/* Path is too short, skip it. */
351 			return (NULL);
352 		}
353 	}
354 
355 	/* Skip any / characters.  This handles short paths that have
356 	 * additional / termination.  This also handles the case where
357 	 * the logic above stops in the middle of a duplicate //
358 	 * sequence (which would otherwise get converted to an
359 	 * absolute path). */
360 	for (;;) {
361 		switch (*p) {
362 		case '/':
363 #if defined(_WIN32) && !defined(__CYGWIN__)
364 		case '\\': /* Support \ path sep on Windows ONLY. */
365 #endif
366 			++p;
367 			break;
368 		case '\0':
369 			return (NULL);
370 		default:
371 			return (p);
372 		}
373 	}
374 }
375 
376 static void
377 warn_strip_leading_char(struct bsdtar *bsdtar, const char *c)
378 {
379 	if (!bsdtar->warned_lead_slash) {
380 		lafe_warnc(0,
381 			   "Removing leading '%c' from member names",
382 			   c[0]);
383 		bsdtar->warned_lead_slash = 1;
384 	}
385 }
386 
387 static void
388 warn_strip_drive_letter(struct bsdtar *bsdtar)
389 {
390 	if (!bsdtar->warned_lead_slash) {
391 		lafe_warnc(0,
392 			   "Removing leading drive letter from "
393 			   "member names");
394 		bsdtar->warned_lead_slash = 1;
395 	}
396 }
397 
398 /*
399  * Convert absolute path to non-absolute path by skipping leading
400  * absolute path prefixes.
401  */
402 static const char*
403 strip_absolute_path(struct bsdtar *bsdtar, const char *p)
404 {
405 	const char *rp;
406 
407 	/* Remove leading "//./" or "//?/" or "//?/UNC/"
408 	 * (absolute path prefixes used by Windows API) */
409 	if ((p[0] == '/' || p[0] == '\\') &&
410 	    (p[1] == '/' || p[1] == '\\') &&
411 	    (p[2] == '.' || p[2] == '?') &&
412 	    (p[3] == '/' || p[3] == '\\'))
413 	{
414 		if (p[2] == '?' &&
415 		    (p[4] == 'U' || p[4] == 'u') &&
416 		    (p[5] == 'N' || p[5] == 'n') &&
417 		    (p[6] == 'C' || p[6] == 'c') &&
418 		    (p[7] == '/' || p[7] == '\\'))
419 			p += 8;
420 		else
421 			p += 4;
422 		warn_strip_drive_letter(bsdtar);
423 	}
424 
425 	/* Remove multiple leading slashes and Windows drive letters. */
426 	do {
427 		rp = p;
428 		if (((p[0] >= 'a' && p[0] <= 'z') ||
429 		     (p[0] >= 'A' && p[0] <= 'Z')) &&
430 		    p[1] == ':') {
431 			p += 2;
432 			warn_strip_drive_letter(bsdtar);
433 		}
434 
435 		/* Remove leading "/../", "/./", "//", etc. */
436 		while (p[0] == '/' || p[0] == '\\') {
437 			if (p[1] == '.' &&
438 			    p[2] == '.' &&
439 			    (p[3] == '/' || p[3] == '\\')) {
440 				p += 3; /* Remove "/..", leave "/" for next pass. */
441 			} else if (p[1] == '.' &&
442 				   (p[2] == '/' || p[2] == '\\')) {
443 				p += 2; /* Remove "/.", leave "/" for next pass. */
444 			} else
445 				p += 1; /* Remove "/". */
446 			warn_strip_leading_char(bsdtar, rp);
447 		}
448 	} while (rp != p);
449 
450 	return (p);
451 }
452 
453 /*
454  * Handle --strip-components and any future path-rewriting options.
455  * Returns non-zero if the pathname should not be extracted.
456  *
457  * Note: The rewrites are applied uniformly to pathnames and hardlink
458  * names but not to symlink bodies.  This is deliberate: Symlink
459  * bodies are not necessarily filenames.  Even when they are, they
460  * need to be interpreted relative to the directory containing them,
461  * so simple rewrites like this are rarely appropriate.
462  *
463  * TODO: Support pax-style regex path rewrites.
464  */
465 int
466 edit_pathname(struct bsdtar *bsdtar, struct archive_entry *entry)
467 {
468 	const char *name = archive_entry_pathname(entry);
469 	const char *original_name = name;
470 	const char *hardlinkname = archive_entry_hardlink(entry);
471 	const char *original_hardlinkname = hardlinkname;
472 #if defined(HAVE_REGEX_H) || defined(HAVE_PCREPOSIX_H)
473 	char *subst_name;
474 	int r;
475 
476 	/* Apply user-specified substitution to pathname. */
477 	r = apply_substitution(bsdtar, name, &subst_name, 0, 0);
478 	if (r == -1) {
479 		lafe_warnc(0, "Invalid substitution, skipping entry");
480 		return 1;
481 	}
482 	if (r == 1) {
483 		archive_entry_copy_pathname(entry, subst_name);
484 		if (*subst_name == '\0') {
485 			free(subst_name);
486 			return -1;
487 		} else
488 			free(subst_name);
489 		name = archive_entry_pathname(entry);
490 		original_name = name;
491 	}
492 
493 	/* Apply user-specified substitution to hardlink target. */
494 	if (hardlinkname != NULL) {
495 		r = apply_substitution(bsdtar, hardlinkname, &subst_name, 0, 1);
496 		if (r == -1) {
497 			lafe_warnc(0, "Invalid substitution, skipping entry");
498 			return 1;
499 		}
500 		if (r == 1) {
501 			archive_entry_copy_hardlink(entry, subst_name);
502 			free(subst_name);
503 		}
504 		hardlinkname = archive_entry_hardlink(entry);
505 		original_hardlinkname = hardlinkname;
506 	}
507 
508 	/* Apply user-specified substitution to symlink body. */
509 	if (archive_entry_symlink(entry) != NULL) {
510 		r = apply_substitution(bsdtar, archive_entry_symlink(entry), &subst_name, 1, 0);
511 		if (r == -1) {
512 			lafe_warnc(0, "Invalid substitution, skipping entry");
513 			return 1;
514 		}
515 		if (r == 1) {
516 			archive_entry_copy_symlink(entry, subst_name);
517 			free(subst_name);
518 		}
519 	}
520 #endif
521 
522 	/* Strip leading dir names as per --strip-components option. */
523 	if (bsdtar->strip_components > 0) {
524 		name = strip_components(name, bsdtar->strip_components);
525 		if (name == NULL)
526 			return (1);
527 
528 		if (hardlinkname != NULL) {
529 			hardlinkname = strip_components(hardlinkname,
530 			    bsdtar->strip_components);
531 			if (hardlinkname == NULL)
532 				return (1);
533 		}
534 	}
535 
536 	if (!bsdtar->option_absolute_paths) {
537 		/* By default, don't write or restore absolute pathnames. */
538 		name = strip_absolute_path(bsdtar, name);
539 		if (*name == '\0')
540 			name = ".";
541 
542 		if (hardlinkname != NULL) {
543 			hardlinkname = strip_absolute_path(bsdtar, hardlinkname);
544 			if (*hardlinkname == '\0')
545 				return (1);
546 		}
547 	} else {
548 		/* Strip redundant leading '/' characters. */
549 		while (name[0] == '/' && name[1] == '/')
550 			name++;
551 	}
552 
553 	/* Replace name in archive_entry. */
554 	if (name != original_name) {
555 		archive_entry_copy_pathname(entry, name);
556 	}
557 	if (hardlinkname != original_hardlinkname) {
558 		archive_entry_copy_hardlink(entry, hardlinkname);
559 	}
560 	return (0);
561 }
562 
563 /*
564  * It would be nice to just use printf() for formatting large numbers,
565  * but the compatibility problems are quite a headache.  Hence the
566  * following simple utility function.
567  */
568 const char *
569 tar_i64toa(int64_t n0)
570 {
571 	static char buff[24];
572 	uint64_t n = n0 < 0 ? -n0 : n0;
573 	char *p = buff + sizeof(buff);
574 
575 	*--p = '\0';
576 	do {
577 		*--p = '0' + (int)(n % 10);
578 	} while (n /= 10);
579 	if (n0 < 0)
580 		*--p = '-';
581 	return p;
582 }
583 
584 /*
585  * Like strcmp(), but try to be a little more aware of the fact that
586  * we're comparing two paths.  Right now, it just handles leading
587  * "./" and trailing '/' specially, so that "a/b/" == "./a/b"
588  *
589  * TODO: Make this better, so that "./a//b/./c/" == "a/b/c"
590  * TODO: After this works, push it down into libarchive.
591  * TODO: Publish the path normalization routines in libarchive so
592  * that bsdtar can normalize paths and use fast strcmp() instead
593  * of this.
594  *
595  * Note: This is currently only used within write.c, so should
596  * not handle \ path separators.
597  */
598 
599 int
600 pathcmp(const char *a, const char *b)
601 {
602 	/* Skip leading './' */
603 	if (a[0] == '.' && a[1] == '/' && a[2] != '\0')
604 		a += 2;
605 	if (b[0] == '.' && b[1] == '/' && b[2] != '\0')
606 		b += 2;
607 	/* Find the first difference, or return (0) if none. */
608 	while (*a == *b) {
609 		if (*a == '\0')
610 			return (0);
611 		a++;
612 		b++;
613 	}
614 	/*
615 	 * If one ends in '/' and the other one doesn't,
616 	 * they're the same.
617 	 */
618 	if (a[0] == '/' && a[1] == '\0' && b[0] == '\0')
619 		return (0);
620 	if (a[0] == '\0' && b[0] == '/' && b[1] == '\0')
621 		return (0);
622 	/* They're really different, return the correct sign. */
623 	return (*(const unsigned char *)a - *(const unsigned char *)b);
624 }
625 
626 #define PPBUFF_SIZE 1024
627 const char *
628 passphrase_callback(struct archive *a, void *_client_data)
629 {
630 	struct bsdtar *bsdtar = (struct bsdtar *)_client_data;
631 	(void)a; /* UNUSED */
632 
633 	if (bsdtar->ppbuff == NULL) {
634 		bsdtar->ppbuff = malloc(PPBUFF_SIZE);
635 		if (bsdtar->ppbuff == NULL)
636 			lafe_errc(1, errno, "Out of memory");
637 	}
638 	return lafe_readpassphrase("Enter passphrase:",
639 		bsdtar->ppbuff, PPBUFF_SIZE);
640 }
641 
642 void
643 passphrase_free(char *ppbuff)
644 {
645 	if (ppbuff != NULL) {
646 		memset(ppbuff, 0, PPBUFF_SIZE);
647 		free(ppbuff);
648 	}
649 }
650 
651 /*
652  * Display information about the current file.
653  *
654  * The format here roughly duplicates the output of 'ls -l'.
655  * This is based on SUSv2, where 'tar tv' is documented as
656  * listing additional information in an "unspecified format,"
657  * and 'pax -l' is documented as using the same format as 'ls -l'.
658  */
659 void
660 list_item_verbose(struct bsdtar *bsdtar, FILE *out, struct archive_entry *entry)
661 {
662 	char			 tmp[100];
663 	size_t			 w;
664 	const char		*p;
665 	const char		*fmt;
666 	time_t			 tim;
667 	static time_t		 now;
668 
669 	/*
670 	 * We avoid collecting the entire list in memory at once by
671 	 * listing things as we see them.  However, that also means we can't
672 	 * just pre-compute the field widths.  Instead, we start with guesses
673 	 * and just widen them as necessary.  These numbers are completely
674 	 * arbitrary.
675 	 */
676 	if (!bsdtar->u_width) {
677 		bsdtar->u_width = 6;
678 		bsdtar->gs_width = 13;
679 	}
680 	if (!now)
681 		time(&now);
682 	fprintf(out, "%s %d ",
683 	    archive_entry_strmode(entry),
684 	    archive_entry_nlink(entry));
685 
686 	/* Use uname if it's present, else uid. */
687 	p = archive_entry_uname(entry);
688 	if ((p == NULL) || (*p == '\0')) {
689 		sprintf(tmp, "%lu ",
690 		    (unsigned long)archive_entry_uid(entry));
691 		p = tmp;
692 	}
693 	w = strlen(p);
694 	if (w > bsdtar->u_width)
695 		bsdtar->u_width = w;
696 	fprintf(out, "%-*s ", (int)bsdtar->u_width, p);
697 
698 	/* Use gname if it's present, else gid. */
699 	p = archive_entry_gname(entry);
700 	if (p != NULL && p[0] != '\0') {
701 		fprintf(out, "%s", p);
702 		w = strlen(p);
703 	} else {
704 		sprintf(tmp, "%lu",
705 		    (unsigned long)archive_entry_gid(entry));
706 		w = strlen(tmp);
707 		fprintf(out, "%s", tmp);
708 	}
709 
710 	/*
711 	 * Print device number or file size, right-aligned so as to make
712 	 * total width of group and devnum/filesize fields be gs_width.
713 	 * If gs_width is too small, grow it.
714 	 */
715 	if (archive_entry_filetype(entry) == AE_IFCHR
716 	    || archive_entry_filetype(entry) == AE_IFBLK) {
717 		sprintf(tmp, "%lu,%lu",
718 		    (unsigned long)archive_entry_rdevmajor(entry),
719 		    (unsigned long)archive_entry_rdevminor(entry));
720 	} else {
721 		strcpy(tmp, tar_i64toa(archive_entry_size(entry)));
722 	}
723 	if (w + strlen(tmp) >= bsdtar->gs_width)
724 		bsdtar->gs_width = w+strlen(tmp)+1;
725 	fprintf(out, "%*s", (int)(bsdtar->gs_width - w), tmp);
726 
727 	/* Format the time using 'ls -l' conventions. */
728 	tim = archive_entry_mtime(entry);
729 #define	HALF_YEAR (time_t)365 * 86400 / 2
730 #if defined(_WIN32) && !defined(__CYGWIN__)
731 #define	DAY_FMT  "%d"  /* Windows' strftime function does not support %e format. */
732 #else
733 #define	DAY_FMT  "%e"  /* Day number without leading zeros */
734 #endif
735 	if (tim < now - HALF_YEAR || tim > now + HALF_YEAR)
736 		fmt = bsdtar->day_first ? DAY_FMT " %b  %Y" : "%b " DAY_FMT "  %Y";
737 	else
738 		fmt = bsdtar->day_first ? DAY_FMT " %b %H:%M" : "%b " DAY_FMT " %H:%M";
739 	strftime(tmp, sizeof(tmp), fmt, localtime(&tim));
740 	fprintf(out, " %s ", tmp);
741 	safe_fprintf(out, "%s", archive_entry_pathname(entry));
742 
743 	/* Extra information for links. */
744 	if (archive_entry_hardlink(entry)) /* Hard link */
745 		safe_fprintf(out, " link to %s",
746 		    archive_entry_hardlink(entry));
747 	else if (archive_entry_symlink(entry)) /* Symbolic link */
748 		safe_fprintf(out, " -> %s", archive_entry_symlink(entry));
749 }
750