xref: /minix/lib/libc/time/zdump.c (revision 84d9c625)
1 /*	$NetBSD: zdump.c,v 1.31 2013/09/20 19:06:54 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 1.31 2013/09/20 19:06:54 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__ || 2 < (__GLIBC__ + (0 < __GLIBC_MINOR__)))
43 #endif
44 #if HAVE_STDINT_H
45 # include "stdint.h"
46 #endif
47 #ifndef HAVE_INTTYPES_H
48 # define HAVE_INTTYPES_H HAVE_STDINT_H
49 #endif
50 #if HAVE_INTTYPES_H
51 # include <inttypes.h>
52 #endif
53 
54 #ifndef INT_FAST32_MAX
55 # if INT_MAX >> 31 == 0
56 typedef long int_fast32_t;
57 # else
58 typedef int int_fast32_t;
59 # endif
60 #endif
61 
62 #ifndef INTMAX_MAX
63 # if defined LLONG_MAX || defined __LONG_LONG_MAX__
64 typedef long long intmax_t;
65 #  define PRIdMAX "lld"
66 #  ifdef LLONG_MAX
67 #   define INTMAX_MAX LLONG_MAX
68 #  else
69 #   define INTMAX_MAX __LONG_LONG_MAX__
70 #  endif
71 # else
72 typedef long intmax_t;
73 #  define PRIdMAX "ld"
74 #  define INTMAX_MAX LONG_MAX
75 # endif
76 #endif
77 #ifndef SCNdMAX
78 # define SCNdMAX PRIdMAX
79 #endif
80 
81 
82 #ifndef ZDUMP_LO_YEAR
83 #define ZDUMP_LO_YEAR	(-500)
84 #endif /* !defined ZDUMP_LO_YEAR */
85 
86 #ifndef ZDUMP_HI_YEAR
87 #define ZDUMP_HI_YEAR	2500
88 #endif /* !defined ZDUMP_HI_YEAR */
89 
90 #ifndef MAX_STRING_LENGTH
91 #define MAX_STRING_LENGTH	1024
92 #endif /* !defined MAX_STRING_LENGTH */
93 
94 #ifndef TRUE
95 #define TRUE		1
96 #endif /* !defined TRUE */
97 
98 #ifndef FALSE
99 #define FALSE		0
100 #endif /* !defined FALSE */
101 
102 #ifndef EXIT_SUCCESS
103 #define EXIT_SUCCESS	0
104 #endif /* !defined EXIT_SUCCESS */
105 
106 #ifndef EXIT_FAILURE
107 #define EXIT_FAILURE	1
108 #endif /* !defined EXIT_FAILURE */
109 
110 #ifndef SECSPERMIN
111 #define SECSPERMIN	60
112 #endif /* !defined SECSPERMIN */
113 
114 #ifndef MINSPERHOUR
115 #define MINSPERHOUR	60
116 #endif /* !defined MINSPERHOUR */
117 
118 #ifndef SECSPERHOUR
119 #define SECSPERHOUR	(SECSPERMIN * MINSPERHOUR)
120 #endif /* !defined SECSPERHOUR */
121 
122 #ifndef HOURSPERDAY
123 #define HOURSPERDAY	24
124 #endif /* !defined HOURSPERDAY */
125 
126 #ifndef EPOCH_YEAR
127 #define EPOCH_YEAR	1970
128 #endif /* !defined EPOCH_YEAR */
129 
130 #ifndef TM_YEAR_BASE
131 #define TM_YEAR_BASE	1900
132 #endif /* !defined TM_YEAR_BASE */
133 
134 #ifndef DAYSPERNYEAR
135 #define DAYSPERNYEAR	365
136 #endif /* !defined DAYSPERNYEAR */
137 
138 #ifndef isleap
139 #define isleap(y) (((y) % 4) == 0 && (((y) % 100) != 0 || ((y) % 400) == 0))
140 #endif /* !defined isleap */
141 
142 #ifndef isleap_sum
143 /*
144 ** See tzfile.h for details on isleap_sum.
145 */
146 #define isleap_sum(a, b)	isleap((a) % 400 + (b) % 400)
147 #endif /* !defined isleap_sum */
148 
149 #define SECSPERDAY	((int_fast32_t) SECSPERHOUR * HOURSPERDAY)
150 #define SECSPERNYEAR	(SECSPERDAY * DAYSPERNYEAR)
151 #define SECSPERLYEAR	(SECSPERNYEAR + SECSPERDAY)
152 #define SECSPER400YEARS	(SECSPERNYEAR * (intmax_t) (300 + 3)	\
153 			 + SECSPERLYEAR * (intmax_t) (100 - 3))
154 
155 /*
156 ** True if SECSPER400YEARS is known to be representable as an
157 ** intmax_t.  It's OK that SECSPER400YEARS_FITS can in theory be false
158 ** even if SECSPER400YEARS is representable, because when that happens
159 ** the code merely runs a bit more slowly, and this slowness doesn't
160 ** occur on any practical platform.
161 */
162 enum { SECSPER400YEARS_FITS = SECSPERLYEAR <= INTMAX_MAX / 400 };
163 
164 #ifndef HAVE_GETTEXT
165 #define HAVE_GETTEXT 0
166 #endif
167 #if HAVE_GETTEXT
168 #include "locale.h"	/* for setlocale */
169 #include "libintl.h"
170 #endif /* HAVE_GETTEXT */
171 
172 #ifndef GNUC_or_lint
173 #ifdef lint
174 #define GNUC_or_lint
175 #else /* !defined lint */
176 #ifdef __GNUC__
177 #define GNUC_or_lint
178 #endif /* defined __GNUC__ */
179 #endif /* !defined lint */
180 #endif /* !defined GNUC_or_lint */
181 
182 #ifndef ATTRIBUTE_PURE
183 #if 2 < __GNUC__ || (__GNUC__ == 2 && 96 <= __GNUC_MINOR__)
184 # define ATTRIBUTE_PURE __attribute__ ((ATTRIBUTE_PURE__))
185 #else
186 # define ATTRIBUTE_PURE /* empty */
187 #endif
188 #endif
189 
190 #ifndef INITIALIZE
191 #ifdef GNUC_or_lint
192 #define INITIALIZE(x)	((x) = 0)
193 #else /* !defined GNUC_or_lint */
194 #define INITIALIZE(x)
195 #endif /* !defined GNUC_or_lint */
196 #endif /* !defined INITIALIZE */
197 
198 /*
199 ** For the benefit of GNU folk...
200 ** `_(MSGID)' uses the current locale's message library string for MSGID.
201 ** The default is to use gettext if available, and use MSGID otherwise.
202 */
203 
204 #ifndef _
205 #if HAVE_GETTEXT
206 #define _(msgid) gettext(msgid)
207 #else /* !HAVE_GETTEXT */
208 #define _(msgid) msgid
209 #endif /* !HAVE_GETTEXT */
210 #endif /* !defined _ */
211 
212 #ifndef TZ_DOMAIN
213 #define TZ_DOMAIN "tz"
214 #endif /* !defined TZ_DOMAIN */
215 
216 extern char **	environ;
217 extern int	getopt(int argc, char * const argv[],
218 			const char * options);
219 extern char *	optarg;
220 extern int	optind;
221 
222 /* The minimum and maximum finite time values.  */
223 static time_t	absolute_min_time =
224   ((time_t) -1 < 0
225     ? (time_t) -1 << (CHAR_BIT * sizeof (time_t) - 1)
226     : 0);
227 static time_t	absolute_max_time =
228   ((time_t) -1 < 0
229     ? - (~ 0 < 0) - ((time_t) -1 << (CHAR_BIT * sizeof (time_t) - 1))
230    : -1);
231 static size_t	longest;
232 static char *	progname;
233 static int	warned;
234 
235 static const char *	abbr(struct tm * tmp);
236 static void	abbrok(const char * abbrp, const char * zone);
237 static intmax_t	delta(struct tm * newp, struct tm * oldp) ATTRIBUTE_PURE;
238 static void	dumptime(const struct tm * tmp);
239 static time_t	hunt(char * name, time_t lot, time_t	hit);
240 static void	show(char * zone, time_t t, int v);
241 static const char *	tformat(void);
242 static time_t	yeartot(long y) ATTRIBUTE_PURE;
243 
244 #ifndef TYPECHECK
245 #define my_localtime	localtime
246 #else /* !defined TYPECHECK */
247 static struct tm *
248 my_localtime(time_t *tp)
249 {
250 	struct tm *tmp;
251 
252 	tmp = localtime(tp);
253 	if (tp != NULL && tmp != NULL) {
254 		struct tm	tm;
255 		time_t	t;
256 
257 		tm = *tmp;
258 		t = mktime(&tm);
259 		if (t != *tp) {
260 			(void) fflush(stdout);
261 			(void) fprintf(stderr, "\n%s: ", progname);
262 			(void) fprintf(stderr, tformat(), *tp);
263 			(void) fprintf(stderr, " ->");
264 			(void) fprintf(stderr, " year=%d", tmp->tm_year);
265 			(void) fprintf(stderr, " mon=%d", tmp->tm_mon);
266 			(void) fprintf(stderr, " mday=%d", tmp->tm_mday);
267 			(void) fprintf(stderr, " hour=%d", tmp->tm_hour);
268 			(void) fprintf(stderr, " min=%d", tmp->tm_min);
269 			(void) fprintf(stderr, " sec=%d", tmp->tm_sec);
270 			(void) fprintf(stderr, " isdst=%d", tmp->tm_isdst);
271 			(void) fprintf(stderr, " -> ");
272 			(void) fprintf(stderr, tformat(), t);
273 			(void) fprintf(stderr, "\n");
274 		}
275 	}
276 	return tmp;
277 }
278 #endif /* !defined TYPECHECK */
279 
280 static void
281 abbrok(const char *const abbrp, const char *const zone)
282 {
283 	const char *cp;
284 	const char *wp;
285 
286 	if (warned)
287 		return;
288 	cp = abbrp;
289 	wp = NULL;
290 	while (isascii((unsigned char) *cp) && isalpha((unsigned char) *cp))
291 		++cp;
292 	if (cp - abbrp == 0)
293 		wp = _("lacks alphabetic at start");
294 	else if (cp - abbrp < 3)
295 		wp = _("has fewer than 3 alphabetics");
296 	else if (cp - abbrp > 6)
297 		wp = _("has more than 6 alphabetics");
298 	if (wp == NULL && (*cp == '+' || *cp == '-')) {
299 		++cp;
300 		if (isascii((unsigned char) *cp) &&
301 			isdigit((unsigned char) *cp))
302 				if (*cp++ == '1' && *cp >= '0' && *cp <= '4')
303 					++cp;
304 		if (*cp != '\0')
305 			wp = _("differs from POSIX standard");
306 	}
307 	if (wp == NULL)
308 		return;
309 	(void) fflush(stdout);
310 	(void) fprintf(stderr,
311 		_("%s: warning: zone \"%s\" abbreviation \"%s\" %s\n"),
312 		progname, zone, abbrp, wp);
313 	warned = TRUE;
314 }
315 
316 __dead static void
317 usage(FILE *const stream, const int status)
318 {
319 	(void) fprintf(stream,
320 _("%s: usage: %s [--version] [--help] [-{vV}] [-{ct} [lo,]hi] zonename ...\n"
321   "\n"
322   "Report bugs to %s.\n"),
323 		       progname, progname, REPORT_BUGS_TO);
324 	exit(status);
325 }
326 
327 int
328 main(int argc, char *argv[])
329 {
330 	int		i;
331 	int		vflag;
332 	int		Vflag;
333 	char *		cutarg;
334 	char *		cuttimes;
335 	time_t		cutlotime;
336 	time_t		cuthitime;
337 	char **		fakeenv;
338 	time_t		now;
339 	time_t		t;
340 	time_t		newt;
341 	struct tm	tm;
342 	struct tm	newtm;
343 	struct tm *	tmp;
344 	struct tm *	newtmp;
345 
346 	cutlotime = absolute_min_time;
347 	cuthitime = absolute_max_time;
348 #if HAVE_GETTEXT
349 	(void) setlocale(LC_ALL, "");
350 #ifdef TZ_DOMAINDIR
351 	(void) bindtextdomain(TZ_DOMAIN, TZ_DOMAINDIR);
352 #endif /* defined TEXTDOMAINDIR */
353 	(void) textdomain(TZ_DOMAIN);
354 #endif /* HAVE_GETTEXT */
355 	progname = argv[0];
356 	for (i = 1; i < argc; ++i)
357 		if (strcmp(argv[i], "--version") == 0) {
358 			(void) printf("zdump %s%s\n", PKGVERSION, TZVERSION);
359 			exit(EXIT_SUCCESS);
360 		} else if (strcmp(argv[i], "--help") == 0) {
361 			usage(stdout, EXIT_SUCCESS);
362 		}
363 	vflag = Vflag = 0;
364 	cutarg = cuttimes = NULL;
365 	for (;;)
366 	  switch (getopt(argc, argv, "c:t:vV")) {
367 	  case 'c': cutarg = optarg; break;
368 	  case 't': cuttimes = optarg; break;
369 	  case 'v': vflag = 1; break;
370 	  case 'V': Vflag = 1; break;
371 	  case -1:
372 	    if (! (optind == argc - 1 && strcmp(argv[optind], "=") == 0))
373 	      goto arg_processing_done;
374 	    /* Fall through.  */
375 	  default:
376 	    usage(stderr, EXIT_FAILURE);
377 	  }
378  arg_processing_done:;
379 
380 	if (vflag | Vflag) {
381 		intmax_t	lo;
382 		intmax_t	hi;
383 		char		dummy;
384 		intmax_t cutloyear = ZDUMP_LO_YEAR;
385 		intmax_t cuthiyear = ZDUMP_HI_YEAR;
386 		if (cutarg != NULL) {
387 			if (sscanf(cutarg, "%"SCNdMAX"%c", &hi, &dummy) == 1) {
388 				cuthiyear = hi;
389 			} else if (sscanf(cutarg, "%"SCNdMAX",%"SCNdMAX"%c",
390 				&lo, &hi, &dummy) == 2) {
391 					cutloyear = lo;
392 					cuthiyear = hi;
393 			} else {
394 (void) fprintf(stderr, _("%s: wild -c argument %s\n"),
395 					progname, cutarg);
396 				exit(EXIT_FAILURE);
397 			}
398 		}
399 		if (cutarg != NULL || cuttimes == NULL) {
400 			cutlotime = yeartot(cutloyear);
401 			cuthitime = yeartot(cuthiyear);
402 		}
403 		if (cuttimes != NULL) {
404 			if (sscanf(cuttimes, "%"SCNdMAX"%c", &hi, &dummy) == 1) {
405 				if (hi < cuthitime) {
406 					if (hi < absolute_min_time)
407 						hi = absolute_min_time;
408 					cuthitime = hi;
409 				}
410 			} else if (sscanf(cuttimes, "%"SCNdMAX",%"SCNdMAX"%c",
411 					  &lo, &hi, &dummy) == 2) {
412 				if (cutlotime < lo) {
413 					if (absolute_max_time < lo)
414 						lo = absolute_max_time;
415 					cutlotime = lo;
416 				}
417 				if (hi < cuthitime) {
418 					if (hi < absolute_min_time)
419 						hi = absolute_min_time;
420 					cuthitime = hi;
421 				}
422 			} else {
423 				(void) fprintf(stderr,
424 					_("%s: wild -t argument %s\n"),
425 					progname, cuttimes);
426 				exit(EXIT_FAILURE);
427 			}
428 		}
429 	}
430 	(void) time(&now);
431 	longest = 0;
432 	for (i = optind; i < argc; ++i)
433 		if (strlen(argv[i]) > longest)
434 			longest = strlen(argv[i]);
435 	{
436 		int	from;
437 		int	to;
438 
439 		for (i = 0; environ[i] != NULL; ++i)
440 			continue;
441 		fakeenv = malloc((i + 2) * sizeof *fakeenv);
442 		if (fakeenv == NULL ||
443 			(fakeenv[0] = malloc(longest + 4)) == NULL) {
444 			err(EXIT_FAILURE, "Can't allocated %zu bytes",
445 			    longest + 4);
446 		}
447 		to = 0;
448 		(void)strcpy(fakeenv[to++], "TZ=");	/* XXX strcpy is safe */
449 		for (from = 0; environ[from] != NULL; ++from)
450 			if (strncmp(environ[from], "TZ=", 3) != 0)
451 				fakeenv[to++] = environ[from];
452 		fakeenv[to] = NULL;
453 		environ = fakeenv;
454 	}
455 	for (i = optind; i < argc; ++i) {
456 		static char	buf[MAX_STRING_LENGTH];
457 
458 		(void) strcpy(&fakeenv[0][3], argv[i]);	/* XXX strcpy is safe */
459 		if (! (vflag | Vflag)) {
460 			show(argv[i], now, FALSE);
461 			continue;
462 		}
463 		warned = FALSE;
464 		t = absolute_min_time;
465 		if (!Vflag) {
466 			show(argv[i], t, TRUE);
467 			t += SECSPERDAY;
468 			show(argv[i], t, TRUE);
469 		}
470 		if (t < cutlotime)
471 			t = cutlotime;
472 		tmp = my_localtime(&t);
473 		if (tmp != NULL) {
474 			tm = *tmp;
475 			(void) strncpy(buf, abbr(&tm), (sizeof buf) - 1);
476 		}
477 		for ( ; ; ) {
478 			newt = (t < absolute_max_time - SECSPERDAY / 2
479 				? t + SECSPERDAY / 2
480 				: absolute_max_time);
481 			if (cuthitime <= newt)
482 				break;
483 			newtmp = localtime(&newt);
484 			if (newtmp != NULL)
485 				newtm = *newtmp;
486 			if ((tmp == NULL || newtmp == NULL) ? (tmp != newtmp) :
487 				(delta(&newtm, &tm) != (newt - t) ||
488 				newtm.tm_isdst != tm.tm_isdst ||
489 				strcmp(abbr(&newtm), buf) != 0)) {
490 					newt = hunt(argv[i], t, newt);
491 					newtmp = localtime(&newt);
492 					if (newtmp != NULL) {
493 						newtm = *newtmp;
494 						(void) strncpy(buf,
495 							abbr(&newtm),
496 							(sizeof buf) - 1);
497 					}
498 			}
499 			t = newt;
500 			tm = newtm;
501 			tmp = newtmp;
502 		}
503 		if (!Vflag) {
504 			t = absolute_max_time;
505 			t -= SECSPERDAY;
506 			show(argv[i], t, TRUE);
507 			t += SECSPERDAY;
508 			show(argv[i], t, TRUE);
509 		}
510 	}
511 	if (fflush(stdout) || ferror(stdout)) {
512 		err(EXIT_FAILURE, _("Error writing standard output"));
513 	}
514 	exit(EXIT_SUCCESS);
515 	/* If exit fails to exit... */
516 	return EXIT_FAILURE;
517 }
518 
519 static time_t
520 yeartot(const long y)
521 {
522 	intmax_t	myy, seconds, years;
523 	time_t		t;
524 
525 	myy = EPOCH_YEAR;
526 	t = 0;
527 	while (myy < y) {
528 		if (SECSPER400YEARS_FITS && 400 <= y - myy) {
529 			intmax_t diff400 = (y - myy) / 400;
530 			if (INTMAX_MAX / SECSPER400YEARS < diff400)
531 				return absolute_max_time;
532 			seconds = diff400 * SECSPER400YEARS;
533 			years = diff400 * 400;
534                 } else {
535 			seconds = isleap(myy) ? SECSPERLYEAR : SECSPERNYEAR;
536 			years = 1;
537 		}
538 		myy += years;
539 		if (t > absolute_max_time - seconds)
540 			return absolute_max_time;
541 		t += seconds;
542 	}
543 	while (y < myy) {
544 		if (SECSPER400YEARS_FITS && y + 400 <= myy && myy < 0) {
545 			intmax_t diff400 = (myy - y) / 400;
546 			if (INTMAX_MAX / SECSPER400YEARS < diff400)
547 				return absolute_min_time;
548 			seconds = diff400 * SECSPER400YEARS;
549 			years = diff400 * 400;
550 		} else {
551 			seconds = isleap(myy - 1) ? SECSPERLYEAR : SECSPERNYEAR;
552 			years = 1;
553 		}
554 		myy -= years;
555 		if (t < absolute_min_time + seconds)
556 			return absolute_min_time;
557 		t -= seconds;
558 	}
559 	return t;
560 }
561 
562 static time_t
563 hunt(char *name, time_t lot, time_t hit)
564 {
565 	time_t			t;
566 	struct tm		lotm;
567 	struct tm *	lotmp;
568 	struct tm		tm;
569 	struct tm *	tmp;
570 	char			loab[MAX_STRING_LENGTH];
571 
572 	lotmp = my_localtime(&lot);
573 	if (lotmp != NULL) {
574 		lotm = *lotmp;
575 		(void) strncpy(loab, abbr(&lotm), (sizeof loab) - 1);
576 	}
577 	for ( ; ; ) {
578 		time_t diff = hit - lot;
579 		if (diff < 2)
580 			break;
581 		t = lot;
582 		t += diff / 2;
583 		if (t <= lot)
584 			++t;
585 		else if (t >= hit)
586 			--t;
587 		tmp = my_localtime(&t);
588 		if (tmp != NULL)
589 			tm = *tmp;
590 		if ((lotmp == NULL || tmp == NULL) ? (lotmp == tmp) :
591 			(delta(&tm, &lotm) == (t - lot) &&
592 			tm.tm_isdst == lotm.tm_isdst &&
593 			strcmp(abbr(&tm), loab) == 0)) {
594 				lot = t;
595 				lotm = tm;
596 				lotmp = tmp;
597 		} else	hit = t;
598 	}
599 	show(name, lot, TRUE);
600 	show(name, hit, TRUE);
601 	return hit;
602 }
603 
604 /*
605 ** Thanks to Paul Eggert for logic used in delta.
606 */
607 
608 static intmax_t
609 delta(struct tm *newp, struct tm *oldp)
610 {
611 	intmax_t	result;
612 	int		tmy;
613 
614 	if (newp->tm_year < oldp->tm_year)
615 		return -delta(oldp, newp);
616 	result = 0;
617 	for (tmy = oldp->tm_year; tmy < newp->tm_year; ++tmy)
618 		result += DAYSPERNYEAR + isleap_sum(tmy, TM_YEAR_BASE);
619 	result += newp->tm_yday - oldp->tm_yday;
620 	result *= HOURSPERDAY;
621 	result += newp->tm_hour - oldp->tm_hour;
622 	result *= MINSPERHOUR;
623 	result += newp->tm_min - oldp->tm_min;
624 	result *= SECSPERMIN;
625 	result += newp->tm_sec - oldp->tm_sec;
626 	return result;
627 }
628 
629 static void
630 show(char *zone, time_t t, int v)
631 {
632 	struct tm *	tmp;
633 
634 	(void) printf("%-*s  ", (int) longest, zone);
635 	if (v) {
636 		tmp = gmtime(&t);
637 		if (tmp == NULL) {
638 			(void) printf(tformat(), t);
639 		} else {
640 			dumptime(tmp);
641 			(void) printf(" UT");
642 		}
643 		(void) printf(" = ");
644 	}
645 	tmp = my_localtime(&t);
646 	dumptime(tmp);
647 	if (tmp != NULL) {
648 		if (*abbr(tmp) != '\0')
649 			(void) printf(" %s", abbr(tmp));
650 		if (v) {
651 			(void) printf(" isdst=%d", tmp->tm_isdst);
652 #ifdef TM_GMTOFF
653 			(void) printf(" gmtoff=%ld", tmp->TM_GMTOFF);
654 #endif /* defined TM_GMTOFF */
655 		}
656 	}
657 	(void) printf("\n");
658 	if (tmp != NULL && *abbr(tmp) != '\0')
659 		abbrok(abbr(tmp), zone);
660 }
661 
662 static const char *
663 abbr(struct tm *tmp)
664 {
665 	const char *	result;
666 	static const char	nada;
667 
668 	if (tmp->tm_isdst != 0 && tmp->tm_isdst != 1)
669 		return &nada;
670 	result = tzname[tmp->tm_isdst];
671 	return (result == NULL) ? &nada : result;
672 }
673 
674 /*
675 ** The code below can fail on certain theoretical systems;
676 ** it works on all known real-world systems as of 2004-12-30.
677 */
678 
679 static const char *
680 tformat(void)
681 {
682 	if (0 > (time_t) -1) {		/* signed */
683 		if (sizeof (time_t) == sizeof (intmax_t))
684 			return "%"PRIdMAX;
685 		if (sizeof (time_t) > sizeof (long))
686 			return "%lld";
687 		if (sizeof (time_t) > sizeof (int))
688 			return "%ld";
689 		return "%d";
690 	}
691 #ifdef PRIuMAX
692 	if (sizeof (time_t) == sizeof (uintmax_t))
693 		return "%"PRIuMAX;
694 #endif
695 	if (sizeof (time_t) > sizeof (unsigned long))
696 		return "%llu";
697 	if (sizeof (time_t) > sizeof (unsigned int))
698 		return "%lu";
699 	return "%u";
700 }
701 
702 static void
703 dumptime(const struct tm *timeptr)
704 {
705 	static const char	wday_name[][3] = {
706 		"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
707 	};
708 	static const char	mon_name[][3] = {
709 		"Jan", "Feb", "Mar", "Apr", "May", "Jun",
710 		"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
711 	};
712 	const char *	wn;
713 	const char *	mn;
714 	int		lead;
715 	int		trail;
716 
717 	if (timeptr == NULL) {
718 		(void) printf("NULL");
719 		return;
720 	}
721 	/*
722 	** The packaged versions of localtime and gmtime never put out-of-range
723 	** values in tm_wday or tm_mon, but since this code might be compiled
724 	** with other (perhaps experimental) versions, paranoia is in order.
725 	*/
726 	if (timeptr->tm_wday < 0 || timeptr->tm_wday >=
727 		(int) (sizeof wday_name / sizeof wday_name[0]))
728 			wn = "???";
729 	else		wn = wday_name[timeptr->tm_wday];
730 	if (timeptr->tm_mon < 0 || timeptr->tm_mon >=
731 		(int) (sizeof mon_name / sizeof mon_name[0]))
732 			mn = "???";
733 	else		mn = mon_name[timeptr->tm_mon];
734 	(void) printf("%.3s %.3s%3d %.2d:%.2d:%.2d ",
735 		wn, mn,
736 		timeptr->tm_mday, timeptr->tm_hour,
737 		timeptr->tm_min, timeptr->tm_sec);
738 #define DIVISOR	10
739 	trail = timeptr->tm_year % DIVISOR + TM_YEAR_BASE % DIVISOR;
740 	lead = timeptr->tm_year / DIVISOR + TM_YEAR_BASE / DIVISOR +
741 		trail / DIVISOR;
742 	trail %= DIVISOR;
743 	if (trail < 0 && lead > 0) {
744 		trail += DIVISOR;
745 		--lead;
746 	} else if (lead < 0 && trail > 0) {
747 		trail -= DIVISOR;
748 		++lead;
749 	}
750 	if (lead == 0)
751 		(void) printf("%d", trail);
752 	else	(void) printf("%d%d", lead, ((trail < 0) ? -trail : trail));
753 }
754