xref: /netbsd-src/lib/libc/time/zdump.c (revision b7b7574d3bf8eeb51a1fa3977b59142ec6434a55)
1 /*	$NetBSD: zdump.c,v 1.33 2014/05/13 16:33:56 christos Exp $	*/
2 /*
3 ** This file is in the public domain, so clarified as of
4 ** 2009-05-17 by Arthur David Olson.
5 */
6 
7 #include <sys/cdefs.h>
8 #ifndef lint
9 __RCSID("$NetBSD: zdump.c,v 1.33 2014/05/13 16:33:56 christos Exp $");
10 #endif /* !defined lint */
11 
12 #include "version.h"
13 /*
14 ** This code has been made independent of the rest of the time
15 ** conversion package to increase confidence in the verification it provides.
16 ** You can use this code to help in verifying other implementations.
17 **
18 ** However, include private.h when debugging, so that it overrides
19 ** time_t consistently with the rest of the package.
20 */
21 
22 #include "private.h"
23 
24 #include "stdio.h"	/* for stdout, stderr */
25 #include "string.h"	/* for strcpy */
26 #include "sys/types.h"	/* for time_t */
27 #include "time.h"	/* for struct tm */
28 #include "stdlib.h"	/* for exit, malloc, atoi */
29 #include <err.h>
30 #include "ctype.h"	/* for isalpha et al. */
31 #ifndef isascii
32 #define isascii(x) 1
33 #endif /* !defined isascii */
34 
35 /*
36 ** Substitutes for pre-C99 compilers.
37 ** Much of this section of code is stolen from private.h.
38 */
39 
40 #ifndef HAVE_STDINT_H
41 # define HAVE_STDINT_H \
42     (199901 <= __STDC_VERSION__ \
43      || 2 < __GLIBC__ + (1 <= __GLIBC_MINOR__)	\
44      || __CYGWIN__)
45 #endif
46 #if HAVE_STDINT_H
47 # include "stdint.h"
48 #endif
49 #ifndef HAVE_INTTYPES_H
50 # define HAVE_INTTYPES_H HAVE_STDINT_H
51 #endif
52 #if HAVE_INTTYPES_H
53 # include <inttypes.h>
54 #endif
55 
56 #ifndef INT_FAST32_MAX
57 # if INT_MAX >> 31 == 0
58 typedef long int_fast32_t;
59 # else
60 typedef int int_fast32_t;
61 # endif
62 #endif
63 
64 #ifndef INTMAX_MAX
65 # if defined LLONG_MAX || defined __LONG_LONG_MAX__
66 typedef long long intmax_t;
67 #  define strtoimax strtoll
68 #  define PRIdMAX "lld"
69 #  ifdef LLONG_MAX
70 #   define INTMAX_MAX LLONG_MAX
71 #  else
72 #   define INTMAX_MAX __LONG_LONG_MAX__
73 #  endif
74 # else
75 typedef long intmax_t;
76 #  define strtoimax strtol
77 #  define PRIdMAX "ld"
78 #  define INTMAX_MAX LONG_MAX
79 # endif
80 #endif
81 
82 
83 #ifndef ZDUMP_LO_YEAR
84 #define ZDUMP_LO_YEAR	(-500)
85 #endif /* !defined ZDUMP_LO_YEAR */
86 
87 #ifndef ZDUMP_HI_YEAR
88 #define ZDUMP_HI_YEAR	2500
89 #endif /* !defined ZDUMP_HI_YEAR */
90 
91 #ifndef MAX_STRING_LENGTH
92 #define MAX_STRING_LENGTH	1024
93 #endif /* !defined MAX_STRING_LENGTH */
94 
95 #ifndef TRUE
96 #define TRUE		1
97 #endif /* !defined TRUE */
98 
99 #ifndef FALSE
100 #define FALSE		0
101 #endif /* !defined FALSE */
102 
103 #ifndef EXIT_SUCCESS
104 #define EXIT_SUCCESS	0
105 #endif /* !defined EXIT_SUCCESS */
106 
107 #ifndef EXIT_FAILURE
108 #define EXIT_FAILURE	1
109 #endif /* !defined EXIT_FAILURE */
110 
111 #ifndef SECSPERMIN
112 #define SECSPERMIN	60
113 #endif /* !defined SECSPERMIN */
114 
115 #ifndef MINSPERHOUR
116 #define MINSPERHOUR	60
117 #endif /* !defined MINSPERHOUR */
118 
119 #ifndef SECSPERHOUR
120 #define SECSPERHOUR	(SECSPERMIN * MINSPERHOUR)
121 #endif /* !defined SECSPERHOUR */
122 
123 #ifndef HOURSPERDAY
124 #define HOURSPERDAY	24
125 #endif /* !defined HOURSPERDAY */
126 
127 #ifndef EPOCH_YEAR
128 #define EPOCH_YEAR	1970
129 #endif /* !defined EPOCH_YEAR */
130 
131 #ifndef TM_YEAR_BASE
132 #define TM_YEAR_BASE	1900
133 #endif /* !defined TM_YEAR_BASE */
134 
135 #ifndef DAYSPERNYEAR
136 #define DAYSPERNYEAR	365
137 #endif /* !defined DAYSPERNYEAR */
138 
139 #ifndef isleap
140 #define isleap(y) (((y) % 4) == 0 && (((y) % 100) != 0 || ((y) % 400) == 0))
141 #endif /* !defined isleap */
142 
143 #ifndef isleap_sum
144 /*
145 ** See tzfile.h for details on isleap_sum.
146 */
147 #define isleap_sum(a, b)	isleap((a) % 400 + (b) % 400)
148 #endif /* !defined isleap_sum */
149 
150 #define SECSPERDAY	((int_fast32_t) SECSPERHOUR * HOURSPERDAY)
151 #define SECSPERNYEAR	(SECSPERDAY * DAYSPERNYEAR)
152 #define SECSPERLYEAR	(SECSPERNYEAR + SECSPERDAY)
153 #define SECSPER400YEARS	(SECSPERNYEAR * (intmax_t) (300 + 3)	\
154 			 + SECSPERLYEAR * (intmax_t) (100 - 3))
155 
156 /*
157 ** True if SECSPER400YEARS is known to be representable as an
158 ** intmax_t.  It's OK that SECSPER400YEARS_FITS can in theory be false
159 ** even if SECSPER400YEARS is representable, because when that happens
160 ** the code merely runs a bit more slowly, and this slowness doesn't
161 ** occur on any practical platform.
162 */
163 enum { SECSPER400YEARS_FITS = SECSPERLYEAR <= INTMAX_MAX / 400 };
164 
165 #ifndef HAVE_GETTEXT
166 #define HAVE_GETTEXT 0
167 #endif
168 #if HAVE_GETTEXT
169 #include "locale.h"	/* for setlocale */
170 #include "libintl.h"
171 #endif /* HAVE_GETTEXT */
172 
173 #ifndef GNUC_or_lint
174 #ifdef lint
175 #define GNUC_or_lint
176 #else /* !defined lint */
177 #ifdef __GNUC__
178 #define GNUC_or_lint
179 #endif /* defined __GNUC__ */
180 #endif /* !defined lint */
181 #endif /* !defined GNUC_or_lint */
182 
183 #ifndef ATTRIBUTE_PURE
184 #if 2 < __GNUC__ || (__GNUC__ == 2 && 96 <= __GNUC_MINOR__)
185 # define ATTRIBUTE_PURE __attribute__ ((ATTRIBUTE_PURE__))
186 #else
187 # define ATTRIBUTE_PURE /* empty */
188 #endif
189 #endif
190 
191 #ifndef INITIALIZE
192 #ifdef GNUC_or_lint
193 #define INITIALIZE(x)	((x) = 0)
194 #else /* !defined GNUC_or_lint */
195 #define INITIALIZE(x)
196 #endif /* !defined GNUC_or_lint */
197 #endif /* !defined INITIALIZE */
198 
199 /*
200 ** For the benefit of GNU folk...
201 ** `_(MSGID)' uses the current locale's message library string for MSGID.
202 ** The default is to use gettext if available, and use MSGID otherwise.
203 */
204 
205 #ifndef _
206 #if HAVE_GETTEXT
207 #define _(msgid) gettext(msgid)
208 #else /* !HAVE_GETTEXT */
209 #define _(msgid) msgid
210 #endif /* !HAVE_GETTEXT */
211 #endif /* !defined _ */
212 
213 #ifndef TZ_DOMAIN
214 #define TZ_DOMAIN "tz"
215 #endif /* !defined TZ_DOMAIN */
216 
217 extern char **	environ;
218 extern int	getopt(int argc, char * const argv[],
219 			const char * options);
220 extern char *	optarg;
221 extern int	optind;
222 
223 /* The minimum and maximum finite time values.  */
224 static time_t	absolute_min_time =
225   ((time_t) -1 < 0
226     ? (time_t) -1 << (CHAR_BIT * sizeof (time_t) - 1)
227     : 0);
228 static time_t	absolute_max_time =
229   ((time_t) -1 < 0
230     ? - (~ 0 < 0) - ((time_t) -1 << (CHAR_BIT * sizeof (time_t) - 1))
231    : -1);
232 static size_t	longest;
233 static char *	progname;
234 static int	warned;
235 
236 static const char *	abbr(struct tm * tmp);
237 static void	abbrok(const char * abbrp, const char * zone);
238 static intmax_t	delta(struct tm * newp, struct tm * oldp) ATTRIBUTE_PURE;
239 static void	dumptime(const struct tm * tmp);
240 static time_t	hunt(char * name, time_t lot, time_t	hit);
241 static void	show(char * zone, time_t t, int v);
242 static const char *	tformat(void);
243 static time_t	yeartot(long y) ATTRIBUTE_PURE;
244 
245 #ifndef TYPECHECK
246 #define my_localtime	localtime
247 #else /* !defined TYPECHECK */
248 static struct tm *
249 my_localtime(time_t *tp)
250 {
251 	struct tm *tmp;
252 
253 	tmp = localtime(tp);
254 	if (tp != NULL && tmp != NULL) {
255 		struct tm	tm;
256 		time_t	t;
257 
258 		tm = *tmp;
259 		t = mktime(&tm);
260 		if (t != *tp) {
261 			(void) fflush(stdout);
262 			(void) fprintf(stderr, "\n%s: ", progname);
263 			(void) fprintf(stderr, tformat(), *tp);
264 			(void) fprintf(stderr, " ->");
265 			(void) fprintf(stderr, " year=%d", tmp->tm_year);
266 			(void) fprintf(stderr, " mon=%d", tmp->tm_mon);
267 			(void) fprintf(stderr, " mday=%d", tmp->tm_mday);
268 			(void) fprintf(stderr, " hour=%d", tmp->tm_hour);
269 			(void) fprintf(stderr, " min=%d", tmp->tm_min);
270 			(void) fprintf(stderr, " sec=%d", tmp->tm_sec);
271 			(void) fprintf(stderr, " isdst=%d", tmp->tm_isdst);
272 			(void) fprintf(stderr, " -> ");
273 			(void) fprintf(stderr, tformat(), t);
274 			(void) fprintf(stderr, "\n");
275 		}
276 	}
277 	return tmp;
278 }
279 #endif /* !defined TYPECHECK */
280 
281 static void
282 abbrok(const char *const abbrp, const char *const zone)
283 {
284 	const char *cp;
285 	const char *wp;
286 
287 	if (warned)
288 		return;
289 	cp = abbrp;
290 	wp = NULL;
291 	while (isascii((unsigned char) *cp) && isalpha((unsigned char) *cp))
292 		++cp;
293 	if (cp - abbrp == 0)
294 		wp = _("lacks alphabetic at start");
295 	else if (cp - abbrp < 3)
296 		wp = _("has fewer than 3 alphabetics");
297 	else if (cp - abbrp > 6)
298 		wp = _("has more than 6 alphabetics");
299 	if (wp == NULL && (*cp == '+' || *cp == '-')) {
300 		++cp;
301 		if (isascii((unsigned char) *cp) &&
302 			isdigit((unsigned char) *cp))
303 				if (*cp++ == '1' && *cp >= '0' && *cp <= '4')
304 					++cp;
305 		if (*cp != '\0')
306 			wp = _("differs from POSIX standard");
307 	}
308 	if (wp == NULL)
309 		return;
310 	(void) fflush(stdout);
311 	(void) fprintf(stderr,
312 		_("%s: warning: zone \"%s\" abbreviation \"%s\" %s\n"),
313 		progname, zone, abbrp, wp);
314 	warned = TRUE;
315 }
316 
317 __dead static void
318 usage(FILE *const stream, const int status)
319 {
320 	(void) fprintf(stream,
321 _("%s: usage: %s [--version] [--help] [-{vV}] [-{ct} [lo,]hi] zonename ...\n"
322   "\n"
323   "Report bugs to %s.\n"),
324 		       progname, progname, REPORT_BUGS_TO);
325 	exit(status);
326 }
327 
328 int
329 main(int argc, char *argv[])
330 {
331 	int		i;
332 	int		vflag;
333 	int		Vflag;
334 	char *		cutarg;
335 	char *		cuttimes;
336 	time_t		cutlotime;
337 	time_t		cuthitime;
338 	char **		fakeenv;
339 	time_t		now;
340 	time_t		t;
341 	time_t		newt;
342 	struct tm	tm;
343 	struct tm	newtm;
344 	struct tm *	tmp;
345 	struct tm *	newtmp;
346 
347 	cutlotime = absolute_min_time;
348 	cuthitime = absolute_max_time;
349 #if HAVE_GETTEXT
350 	(void) setlocale(LC_ALL, "");
351 #ifdef TZ_DOMAINDIR
352 	(void) bindtextdomain(TZ_DOMAIN, TZ_DOMAINDIR);
353 #endif /* defined TEXTDOMAINDIR */
354 	(void) textdomain(TZ_DOMAIN);
355 #endif /* HAVE_GETTEXT */
356 	progname = argv[0];
357 	for (i = 1; i < argc; ++i)
358 		if (strcmp(argv[i], "--version") == 0) {
359 			(void) printf("zdump %s%s\n", PKGVERSION, TZVERSION);
360 			exit(EXIT_SUCCESS);
361 		} else if (strcmp(argv[i], "--help") == 0) {
362 			usage(stdout, EXIT_SUCCESS);
363 		}
364 	vflag = Vflag = 0;
365 	cutarg = cuttimes = NULL;
366 	for (;;)
367 	  switch (getopt(argc, argv, "c:t:vV")) {
368 	  case 'c': cutarg = optarg; break;
369 	  case 't': cuttimes = optarg; break;
370 	  case 'v': vflag = 1; break;
371 	  case 'V': Vflag = 1; break;
372 	  case -1:
373 	    if (! (optind == argc - 1 && strcmp(argv[optind], "=") == 0))
374 	      goto arg_processing_done;
375 	    /* Fall through.  */
376 	  default:
377 	    usage(stderr, EXIT_FAILURE);
378 	  }
379  arg_processing_done:;
380 
381 	if (vflag | Vflag) {
382 		intmax_t	lo;
383 		intmax_t	hi;
384 		char *loend, *hiend;
385 		intmax_t cutloyear = ZDUMP_LO_YEAR;
386 		intmax_t cuthiyear = ZDUMP_HI_YEAR;
387 		if (cutarg != NULL) {
388 			lo = strtoimax(cutarg, &loend, 10);
389 			if (cutarg != loend && !*loend) {
390 				hi = lo;
391 				cuthiyear = hi;
392 			} else if (cutarg != loend && *loend == ','
393 				   && (hi = strtoimax(loend + 1, &hiend, 10),
394 				       loend + 1 != hiend && !*hiend)) {
395 				cutloyear = lo;
396 				cuthiyear = hi;
397 			} else {
398 (void) fprintf(stderr, _("%s: wild -c argument %s\n"),
399 					progname, cutarg);
400 				exit(EXIT_FAILURE);
401 			}
402 		}
403 		if (cutarg != NULL || cuttimes == NULL) {
404 			cutlotime = yeartot(cutloyear);
405 			cuthitime = yeartot(cuthiyear);
406 		}
407 		if (cuttimes != NULL) {
408 			lo = strtoimax(cuttimes, &loend, 10);
409 			if (cuttimes != loend && !*loend) {
410 				hi = lo;
411 				if (hi < cuthitime) {
412 					if (hi < absolute_min_time)
413 						hi = absolute_min_time;
414 					cuthitime = hi;
415 				}
416 			} else if (cuttimes != loend && *loend == ','
417 				   && (hi = strtoimax(loend + 1, &hiend, 10),
418 				       loend + 1 != hiend && !*hiend)) {
419 				if (cutlotime < lo) {
420 					if (absolute_max_time < lo)
421 						lo = absolute_max_time;
422 					cutlotime = lo;
423 				}
424 				if (hi < cuthitime) {
425 					if (hi < absolute_min_time)
426 						hi = absolute_min_time;
427 					cuthitime = hi;
428 				}
429 			} else {
430 				(void) fprintf(stderr,
431 					_("%s: wild -t argument %s\n"),
432 					progname, cuttimes);
433 				exit(EXIT_FAILURE);
434 			}
435 		}
436 	}
437 	(void) time(&now);
438 	longest = 0;
439 	for (i = optind; i < argc; ++i)
440 		if (strlen(argv[i]) > longest)
441 			longest = strlen(argv[i]);
442 	{
443 		int	from;
444 		int	to;
445 
446 		for (i = 0; environ[i] != NULL; ++i)
447 			continue;
448 		fakeenv = malloc((i + 2) * sizeof *fakeenv);
449 		if (fakeenv == NULL ||
450 			(fakeenv[0] = malloc(longest + 4)) == NULL) {
451 			err(EXIT_FAILURE, "Can't allocated %zu bytes",
452 			    longest + 4);
453 		}
454 		to = 0;
455 		(void)strcpy(fakeenv[to++], "TZ=");	/* XXX strcpy is safe */
456 		for (from = 0; environ[from] != NULL; ++from)
457 			if (strncmp(environ[from], "TZ=", 3) != 0)
458 				fakeenv[to++] = environ[from];
459 		fakeenv[to] = NULL;
460 		environ = fakeenv;
461 	}
462 	for (i = optind; i < argc; ++i) {
463 		static char	buf[MAX_STRING_LENGTH];
464 
465 		(void) strcpy(&fakeenv[0][3], argv[i]);	/* XXX strcpy is safe */
466 		if (! (vflag | Vflag)) {
467 			show(argv[i], now, FALSE);
468 			continue;
469 		}
470 		warned = FALSE;
471 		t = absolute_min_time;
472 		if (!Vflag) {
473 			show(argv[i], t, TRUE);
474 			t += SECSPERDAY;
475 			show(argv[i], t, TRUE);
476 		}
477 		if (t < cutlotime)
478 			t = cutlotime;
479 		tmp = my_localtime(&t);
480 		if (tmp != NULL) {
481 			tm = *tmp;
482 			(void) strncpy(buf, abbr(&tm), (sizeof buf) - 1);
483 		}
484 		for ( ; ; ) {
485 			newt = (t < absolute_max_time - SECSPERDAY / 2
486 				? t + SECSPERDAY / 2
487 				: absolute_max_time);
488 			if (cuthitime <= newt)
489 				break;
490 			newtmp = localtime(&newt);
491 			if (newtmp != NULL)
492 				newtm = *newtmp;
493 			if ((tmp == NULL || newtmp == NULL) ? (tmp != newtmp) :
494 				(delta(&newtm, &tm) != (newt - t) ||
495 				newtm.tm_isdst != tm.tm_isdst ||
496 				strcmp(abbr(&newtm), buf) != 0)) {
497 					newt = hunt(argv[i], t, newt);
498 					newtmp = localtime(&newt);
499 					if (newtmp != NULL) {
500 						newtm = *newtmp;
501 						(void) strncpy(buf,
502 							abbr(&newtm),
503 							(sizeof buf) - 1);
504 					}
505 			}
506 			t = newt;
507 			tm = newtm;
508 			tmp = newtmp;
509 		}
510 		if (!Vflag) {
511 			t = absolute_max_time;
512 			t -= SECSPERDAY;
513 			show(argv[i], t, TRUE);
514 			t += SECSPERDAY;
515 			show(argv[i], t, TRUE);
516 		}
517 	}
518 	if (fflush(stdout) || ferror(stdout)) {
519 		err(EXIT_FAILURE, _("Error writing standard output"));
520 	}
521 	exit(EXIT_SUCCESS);
522 	/* If exit fails to exit... */
523 	return EXIT_FAILURE;
524 }
525 
526 static time_t
527 yeartot(const long y)
528 {
529 	intmax_t	myy, seconds, years;
530 	time_t		t;
531 
532 	myy = EPOCH_YEAR;
533 	t = 0;
534 	while (myy < y) {
535 		if (SECSPER400YEARS_FITS && 400 <= y - myy) {
536 			intmax_t diff400 = (y - myy) / 400;
537 			if (INTMAX_MAX / SECSPER400YEARS < diff400)
538 				return absolute_max_time;
539 			seconds = diff400 * SECSPER400YEARS;
540 			years = diff400 * 400;
541                 } else {
542 			seconds = isleap(myy) ? SECSPERLYEAR : SECSPERNYEAR;
543 			years = 1;
544 		}
545 		myy += years;
546 		if (t > absolute_max_time - seconds)
547 			return absolute_max_time;
548 		t += seconds;
549 	}
550 	while (y < myy) {
551 		if (SECSPER400YEARS_FITS && y + 400 <= myy && myy < 0) {
552 			intmax_t diff400 = (myy - y) / 400;
553 			if (INTMAX_MAX / SECSPER400YEARS < diff400)
554 				return absolute_min_time;
555 			seconds = diff400 * SECSPER400YEARS;
556 			years = diff400 * 400;
557 		} else {
558 			seconds = isleap(myy - 1) ? SECSPERLYEAR : SECSPERNYEAR;
559 			years = 1;
560 		}
561 		myy -= years;
562 		if (t < absolute_min_time + seconds)
563 			return absolute_min_time;
564 		t -= seconds;
565 	}
566 	return t;
567 }
568 
569 static time_t
570 hunt(char *name, time_t lot, time_t hit)
571 {
572 	time_t			t;
573 	struct tm		lotm;
574 	struct tm *	lotmp;
575 	struct tm		tm;
576 	struct tm *	tmp;
577 	char			loab[MAX_STRING_LENGTH];
578 
579 	lotmp = my_localtime(&lot);
580 	if (lotmp != NULL) {
581 		lotm = *lotmp;
582 		(void) strncpy(loab, abbr(&lotm), (sizeof loab) - 1);
583 	}
584 	for ( ; ; ) {
585 		time_t diff = hit - lot;
586 		if (diff < 2)
587 			break;
588 		t = lot;
589 		t += diff / 2;
590 		if (t <= lot)
591 			++t;
592 		else if (t >= hit)
593 			--t;
594 		tmp = my_localtime(&t);
595 		if (tmp != NULL)
596 			tm = *tmp;
597 		if ((lotmp == NULL || tmp == NULL) ? (lotmp == tmp) :
598 			(delta(&tm, &lotm) == (t - lot) &&
599 			tm.tm_isdst == lotm.tm_isdst &&
600 			strcmp(abbr(&tm), loab) == 0)) {
601 				lot = t;
602 				lotm = tm;
603 				lotmp = tmp;
604 		} else	hit = t;
605 	}
606 	show(name, lot, TRUE);
607 	show(name, hit, TRUE);
608 	return hit;
609 }
610 
611 /*
612 ** Thanks to Paul Eggert for logic used in delta.
613 */
614 
615 static intmax_t
616 delta(struct tm *newp, struct tm *oldp)
617 {
618 	intmax_t	result;
619 	int		tmy;
620 
621 	if (newp->tm_year < oldp->tm_year)
622 		return -delta(oldp, newp);
623 	result = 0;
624 	for (tmy = oldp->tm_year; tmy < newp->tm_year; ++tmy)
625 		result += DAYSPERNYEAR + isleap_sum(tmy, TM_YEAR_BASE);
626 	result += newp->tm_yday - oldp->tm_yday;
627 	result *= HOURSPERDAY;
628 	result += newp->tm_hour - oldp->tm_hour;
629 	result *= MINSPERHOUR;
630 	result += newp->tm_min - oldp->tm_min;
631 	result *= SECSPERMIN;
632 	result += newp->tm_sec - oldp->tm_sec;
633 	return result;
634 }
635 
636 static void
637 show(char *zone, time_t t, int v)
638 {
639 	struct tm *	tmp;
640 
641 	(void) printf("%-*s  ", (int) longest, zone);
642 	if (v) {
643 		tmp = gmtime(&t);
644 		if (tmp == NULL) {
645 			(void) printf(tformat(), t);
646 		} else {
647 			dumptime(tmp);
648 			(void) printf(" UT");
649 		}
650 		(void) printf(" = ");
651 	}
652 	tmp = my_localtime(&t);
653 	dumptime(tmp);
654 	if (tmp != NULL) {
655 		if (*abbr(tmp) != '\0')
656 			(void) printf(" %s", abbr(tmp));
657 		if (v) {
658 			(void) printf(" isdst=%d", tmp->tm_isdst);
659 #ifdef TM_GMTOFF
660 			(void) printf(" gmtoff=%ld", tmp->TM_GMTOFF);
661 #endif /* defined TM_GMTOFF */
662 		}
663 	}
664 	(void) printf("\n");
665 	if (tmp != NULL && *abbr(tmp) != '\0')
666 		abbrok(abbr(tmp), zone);
667 }
668 
669 static const char *
670 abbr(struct tm *tmp)
671 {
672 	const char *	result;
673 	static const char	nada;
674 
675 	if (tmp->tm_isdst != 0 && tmp->tm_isdst != 1)
676 		return &nada;
677 	result = tzname[tmp->tm_isdst];
678 	return (result == NULL) ? &nada : result;
679 }
680 
681 /*
682 ** The code below can fail on certain theoretical systems;
683 ** it works on all known real-world systems as of 2004-12-30.
684 */
685 
686 static const char *
687 tformat(void)
688 {
689 	if (0 > (time_t) -1) {		/* signed */
690 		if (sizeof (time_t) == sizeof (intmax_t))
691 			return "%"PRIdMAX;
692 		if (sizeof (time_t) > sizeof (long))
693 			return "%lld";
694 		if (sizeof (time_t) > sizeof (int))
695 			return "%ld";
696 		return "%d";
697 	}
698 #ifdef PRIuMAX
699 	if (sizeof (time_t) == sizeof (uintmax_t))
700 		return "%"PRIuMAX;
701 #endif
702 	if (sizeof (time_t) > sizeof (unsigned long))
703 		return "%llu";
704 	if (sizeof (time_t) > sizeof (unsigned int))
705 		return "%lu";
706 	return "%u";
707 }
708 
709 static void
710 dumptime(const struct tm *timeptr)
711 {
712 	static const char	wday_name[][3] = {
713 		"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
714 	};
715 	static const char	mon_name[][3] = {
716 		"Jan", "Feb", "Mar", "Apr", "May", "Jun",
717 		"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
718 	};
719 	const char *	wn;
720 	const char *	mn;
721 	int		lead;
722 	int		trail;
723 
724 	if (timeptr == NULL) {
725 		(void) printf("NULL");
726 		return;
727 	}
728 	/*
729 	** The packaged versions of localtime and gmtime never put out-of-range
730 	** values in tm_wday or tm_mon, but since this code might be compiled
731 	** with other (perhaps experimental) versions, paranoia is in order.
732 	*/
733 	if (timeptr->tm_wday < 0 || timeptr->tm_wday >=
734 		(int) (sizeof wday_name / sizeof wday_name[0]))
735 			wn = "???";
736 	else		wn = wday_name[timeptr->tm_wday];
737 	if (timeptr->tm_mon < 0 || timeptr->tm_mon >=
738 		(int) (sizeof mon_name / sizeof mon_name[0]))
739 			mn = "???";
740 	else		mn = mon_name[timeptr->tm_mon];
741 	(void) printf("%.3s %.3s%3d %.2d:%.2d:%.2d ",
742 		wn, mn,
743 		timeptr->tm_mday, timeptr->tm_hour,
744 		timeptr->tm_min, timeptr->tm_sec);
745 #define DIVISOR	10
746 	trail = timeptr->tm_year % DIVISOR + TM_YEAR_BASE % DIVISOR;
747 	lead = timeptr->tm_year / DIVISOR + TM_YEAR_BASE / DIVISOR +
748 		trail / DIVISOR;
749 	trail %= DIVISOR;
750 	if (trail < 0 && lead > 0) {
751 		trail += DIVISOR;
752 		--lead;
753 	} else if (lead < 0 && trail > 0) {
754 		trail -= DIVISOR;
755 		++lead;
756 	}
757 	if (lead == 0)
758 		(void) printf("%d", trail);
759 	else	(void) printf("%d%d", lead, ((trail < 0) ? -trail : trail));
760 }
761