xref: /netbsd-src/lib/libc/time/zdump.c (revision f89f6560d453f5e37386cc7938c072d2f528b9fa)
1 /*	$NetBSD: zdump.c,v 1.40 2014/10/23 21:19:53 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 1.40 2014/10/23 21:19:53 christos Exp $");
10 #endif /* !defined lint */
11 
12 /*
13 ** This code has been made independent of the rest of the time
14 ** conversion package to increase confidence in the verification it provides.
15 ** You can use this code to help in verifying other implementations.
16 **
17 ** To do this, compile with -DUSE_LTZ=0 and link without the tz library.
18 */
19 
20 #ifndef NETBSD_INSPIRED
21 # define NETBSD_INSPIRED 1
22 #endif
23 #ifndef USE_LTZ
24 # define USE_LTZ 1
25 #endif
26 
27 #if USE_LTZ
28 #include "private.h"
29 #endif
30 
31 /* Enable tm_gmtoff and tm_zone on GNUish systems.  */
32 #define _GNU_SOURCE 1
33 /* Enable strtoimax on Solaris 10.  */
34 #define __EXTENSIONS__ 1
35 
36 #include "stdio.h"	/* for stdout, stderr */
37 #include "string.h"	/* for strcpy */
38 #include "sys/types.h"	/* for time_t */
39 #include "time.h"	/* for struct tm */
40 #include "stdlib.h"	/* for exit, malloc, atoi */
41 #include "limits.h"	/* for CHAR_BIT, LLONG_MAX */
42 #include <errno.h>
43 #include <err.h>
44 
45 /*
46 ** Substitutes for pre-C99 compilers.
47 ** Much of this section of code is stolen from private.h.
48 */
49 
50 #ifndef HAVE_STDINT_H
51 # define HAVE_STDINT_H \
52     (199901 <= __STDC_VERSION__ \
53      || 2 < __GLIBC__ + (1 <= __GLIBC_MINOR__)	\
54      || __CYGWIN__)
55 #endif
56 #if HAVE_STDINT_H
57 # include "stdint.h"
58 #endif
59 #ifndef HAVE_INTTYPES_H
60 # define HAVE_INTTYPES_H HAVE_STDINT_H
61 #endif
62 #if HAVE_INTTYPES_H
63 # include <inttypes.h>
64 #endif
65 
66 #ifndef INT_FAST32_MAX
67 # if INT_MAX >> 31 == 0
68 typedef long int_fast32_t;
69 # else
70 typedef int int_fast32_t;
71 # endif
72 #endif
73 
74 /* Pre-C99 GCC compilers define __LONG_LONG_MAX__ instead of LLONG_MAX.  */
75 #if !defined LLONG_MAX && defined __LONG_LONG_MAX__
76 # define LLONG_MAX __LONG_LONG_MAX__
77 #endif
78 
79 #ifndef INTMAX_MAX
80 # ifdef LLONG_MAX
81 typedef long long intmax_t;
82 #  define strtoimax strtoll
83 #  define INTMAX_MAX LLONG_MAX
84 # else
85 typedef long intmax_t;
86 #  define strtoimax strtol
87 #  define INTMAX_MAX LONG_MAX
88 # endif
89 #endif
90 
91 #ifndef PRIdMAX
92 # if INTMAX_MAX == LLONG_MAX
93 #  define PRIdMAX "lld"
94 # else
95 #  define PRIdMAX "ld"
96 # endif
97 #endif
98 
99 /* Infer TM_ZONE on systems where this information is known, but suppress
100    guessing if NO_TM_ZONE is defined.  Similarly for TM_GMTOFF.  */
101 #if (defined __GLIBC__ \
102      || defined __FreeBSD__ || defined __NetBSD__ || defined __OpenBSD__ \
103      || (defined __APPLE__ && defined __MACH__))
104 # if !defined TM_GMTOFF && !defined NO_TM_GMTOFF
105 #  define TM_GMTOFF tm_gmtoff
106 # endif
107 # if !defined TM_ZONE && !defined NO_TM_ZONE
108 #  define TM_ZONE tm_zone
109 # endif
110 #endif
111 
112 #ifndef HAVE_LOCALTIME_R
113 # define HAVE_LOCALTIME_R 1
114 #endif
115 
116 #ifndef HAVE_LOCALTIME_RZ
117 # ifdef TM_ZONE
118 #  define HAVE_LOCALTIME_RZ (NETBSD_INSPIRED && USE_LTZ)
119 # else
120 #  define HAVE_LOCALTIME_RZ 0
121 # endif
122 #endif
123 
124 #ifndef HAVE_TZSET
125 # define HAVE_TZSET 1
126 #endif
127 
128 #ifndef ZDUMP_LO_YEAR
129 #define ZDUMP_LO_YEAR	(-500)
130 #endif /* !defined ZDUMP_LO_YEAR */
131 
132 #ifndef ZDUMP_HI_YEAR
133 #define ZDUMP_HI_YEAR	2500
134 #endif /* !defined ZDUMP_HI_YEAR */
135 
136 #ifndef MAX_STRING_LENGTH
137 #define MAX_STRING_LENGTH	1024
138 #endif /* !defined MAX_STRING_LENGTH */
139 
140 #if __STDC_VERSION__ < 199901
141 # define true 1
142 # define false 0
143 # define bool int
144 #else
145 # include <stdbool.h>
146 #endif
147 
148 #ifndef EXIT_SUCCESS
149 #define EXIT_SUCCESS	0
150 #endif /* !defined EXIT_SUCCESS */
151 
152 #ifndef EXIT_FAILURE
153 #define EXIT_FAILURE	1
154 #endif /* !defined EXIT_FAILURE */
155 
156 #ifndef SECSPERMIN
157 #define SECSPERMIN	60
158 #endif /* !defined SECSPERMIN */
159 
160 #ifndef MINSPERHOUR
161 #define MINSPERHOUR	60
162 #endif /* !defined MINSPERHOUR */
163 
164 #ifndef SECSPERHOUR
165 #define SECSPERHOUR	(SECSPERMIN * MINSPERHOUR)
166 #endif /* !defined SECSPERHOUR */
167 
168 #ifndef HOURSPERDAY
169 #define HOURSPERDAY	24
170 #endif /* !defined HOURSPERDAY */
171 
172 #ifndef EPOCH_YEAR
173 #define EPOCH_YEAR	1970
174 #endif /* !defined EPOCH_YEAR */
175 
176 #ifndef TM_YEAR_BASE
177 #define TM_YEAR_BASE	1900
178 #endif /* !defined TM_YEAR_BASE */
179 
180 #ifndef DAYSPERNYEAR
181 #define DAYSPERNYEAR	365
182 #endif /* !defined DAYSPERNYEAR */
183 
184 #ifndef isleap
185 #define isleap(y) (((y) % 4) == 0 && (((y) % 100) != 0 || ((y) % 400) == 0))
186 #endif /* !defined isleap */
187 
188 #ifndef isleap_sum
189 /*
190 ** See tzfile.h for details on isleap_sum.
191 */
192 #define isleap_sum(a, b)	isleap((a) % 400 + (b) % 400)
193 #endif /* !defined isleap_sum */
194 
195 #define SECSPERDAY	((int_fast32_t) SECSPERHOUR * HOURSPERDAY)
196 #define SECSPERNYEAR	(SECSPERDAY * DAYSPERNYEAR)
197 #define SECSPERLYEAR	(SECSPERNYEAR + SECSPERDAY)
198 #define SECSPER400YEARS	(SECSPERNYEAR * (intmax_t) (300 + 3)	\
199 			 + SECSPERLYEAR * (intmax_t) (100 - 3))
200 
201 /*
202 ** True if SECSPER400YEARS is known to be representable as an
203 ** intmax_t.  It's OK that SECSPER400YEARS_FITS can in theory be false
204 ** even if SECSPER400YEARS is representable, because when that happens
205 ** the code merely runs a bit more slowly, and this slowness doesn't
206 ** occur on any practical platform.
207 */
208 enum { SECSPER400YEARS_FITS = SECSPERLYEAR <= INTMAX_MAX / 400 };
209 
210 #ifndef HAVE_GETTEXT
211 #define HAVE_GETTEXT 0
212 #endif
213 #if HAVE_GETTEXT
214 #include "locale.h"	/* for setlocale */
215 #include "libintl.h"
216 #endif /* HAVE_GETTEXT */
217 
218 #ifndef ATTRIBUTE_PURE
219 #if 2 < __GNUC__ || (__GNUC__ == 2 && 96 <= __GNUC_MINOR__)
220 # define ATTRIBUTE_PURE __attribute__ ((ATTRIBUTE_PURE__))
221 #else
222 # define ATTRIBUTE_PURE /* empty */
223 #endif
224 #endif
225 
226 #ifndef INITIALIZE
227 #if defined(__GNUC__) || defined(__lint__)
228 #define INITIALIZE(x)	((x) = 0)
229 #else /* !defined GNUC || lint */
230 #define INITIALIZE(x)
231 #endif /* !defined GNUC || lint */
232 #endif /* !defined INITIALIZE */
233 
234 /*
235 ** For the benefit of GNU folk...
236 ** '_(MSGID)' uses the current locale's message library string for MSGID.
237 ** The default is to use gettext if available, and use MSGID otherwise.
238 */
239 
240 #ifndef _
241 #if HAVE_GETTEXT
242 #define _(msgid) gettext(msgid)
243 #else /* !HAVE_GETTEXT */
244 #define _(msgid) msgid
245 #endif /* !HAVE_GETTEXT */
246 #endif /* !defined _ */
247 
248 #if !defined TZ_DOMAIN && defined HAVE_GETTEXT
249 # define TZ_DOMAIN "tz"
250 #endif
251 
252 #if ! HAVE_LOCALTIME_RZ
253 # undef  timezone_t
254 # define timezone_t char **
255 #endif
256 
257 extern char **	environ;
258 extern int	getopt(int argc, char * const argv[],
259 			const char * options);
260 extern char *	optarg;
261 extern int	optind;
262 
263 /* The minimum and maximum finite time values.  */
264 static time_t	absolute_min_time =
265   ((time_t) -1 < 0
266     ? (time_t) -1 << (CHAR_BIT * sizeof (time_t) - 1)
267     : 0);
268 static time_t	absolute_max_time =
269   ((time_t) -1 < 0
270     ? - (~ 0 < 0) - ((time_t) -1 << (CHAR_BIT * sizeof (time_t) - 1))
271    : -1);
272 static size_t	longest;
273 static char *	progname;
274 static bool	warned;
275 static bool	errout;
276 
277 static char const *abbr(struct tm const *);
278 static intmax_t	delta(struct tm *, struct tm *) ATTRIBUTE_PURE;
279 static void dumptime(struct tm const *);
280 static time_t hunt(timezone_t, char *, time_t, time_t);
281 static void show(timezone_t, char *, time_t, bool);
282 static const char *tformat(void);
283 static time_t yeartot(intmax_t) ATTRIBUTE_PURE;
284 
285 /* Is A an alphabetic character in the C locale?  */
286 static bool
287 is_alpha(char a)
288 {
289 	switch (a) {
290 	  default:
291 		return false;
292 	  case 'A': case 'B': case 'C': case 'D': case 'E': case 'F': case 'G':
293 	  case 'H': case 'I': case 'J': case 'K': case 'L': case 'M': case 'N':
294 	  case 'O': case 'P': case 'Q': case 'R': case 'S': case 'T': case 'U':
295 	  case 'V': case 'W': case 'X': case 'Y': case 'Z':
296 	  case 'a': case 'b': case 'c': case 'd': case 'e': case 'f': case 'g':
297 	  case 'h': case 'i': case 'j': case 'k': case 'l': case 'm': case 'n':
298 	  case 'o': case 'p': case 'q': case 'r': case 's': case 't': case 'u':
299 	  case 'v': case 'w': case 'x': case 'y': case 'z':
300 	  	return true;
301 	}
302 }
303 
304 /* Return A + B, exiting if the result would overflow.  */
305 static size_t
306 sumsize(size_t a, size_t b)
307 {
308 	size_t sum = a + b;
309 	if (sum < a)
310 		errx(EXIT_FAILURE, "size overflow");
311 	return sum;
312 }
313 
314 #if ! HAVE_TZSET
315 # undef tzset
316 # define tzset zdump_tzset
317 static void tzset(void) { }
318 #endif
319 
320 /* Assume gmtime_r works if localtime_r does.
321    A replacement localtime_r is defined below if needed.  */
322 #if ! HAVE_LOCALTIME_R
323 
324 # undef gmtime_r
325 # define gmtime_r zdump_gmtime_r
326 
327 static struct tm *
328 gmtime_r(time_t *tp, struct tm *tmp)
329 {
330 	struct tm *r = gmtime(tp);
331 	if (r) {
332 		*tmp = *r;
333 		r = tmp;
334 	}
335 	return r;
336 }
337 
338 #endif
339 
340 /* Platforms with TM_ZONE don't need tzname, so they can use the
341    faster localtime_rz or localtime_r if available.  */
342 
343 #if defined TM_ZONE && HAVE_LOCALTIME_RZ
344 # define USE_LOCALTIME_RZ true
345 #else
346 # define USE_LOCALTIME_RZ false
347 #endif
348 
349 #if ! USE_LOCALTIME_RZ
350 
351 # if !defined TM_ZONE || ! HAVE_LOCALTIME_R || ! HAVE_TZSET
352 #  undef localtime_r
353 #  define localtime_r zdump_localtime_r
354 static struct tm *
355 localtime_r(time_t *tp, struct tm *tmp)
356 {
357 	struct tm *r = localtime(tp);
358 	if (r) {
359 		*tmp = *r;
360 		r = tmp;
361 	}
362 	return r;
363 }
364 # endif
365 
366 # undef localtime_rz
367 # define localtime_rz zdump_localtime_rz
368 static struct tm *
369 localtime_rz(timezone_t rz, time_t *tp, struct tm *tmp)
370 {
371 	return localtime_r(tp, tmp);
372 }
373 
374 # ifdef TYPECHECK
375 #  undef mktime_z
376 #  define mktime_z zdump_mktime_z
377 static time_t
378 mktime_z(timezone_t tz, struct tm *tmp)
379 {
380 	return mktime(tmp);
381 }
382 # endif
383 
384 # undef tzalloc
385 # undef tzfree
386 # define tzalloc zdump_tzalloc
387 # define tzfree zdump_tzfree
388 
389 static timezone_t
390 tzalloc(char const *val)
391 {
392 	static char **fakeenv;
393 	char **env = fakeenv;
394 	char *env0;
395 	if (! env) {
396 		char **e = environ;
397 		int to;
398 
399 		while (*e++)
400 			continue;
401 		env = malloc(sumsize(sizeof *environ,
402 		    (e - environ) * sizeof *environ));
403 		if (! env) {
404 			err(EXIT_FAILURE, "malloc");
405 		}
406 		to = 1;
407 		for (e = environ; (env[to] = *e); e++)
408 			to += strncmp(*e, "TZ=", 3) != 0;
409 	}
410 	env0 = malloc(sumsize(sizeof "TZ=", strlen(val)));
411 	if (! env0) {
412 		err(EXIT_FAILURE, "malloc");
413 	}
414 	env[0] = strcat(strcpy(env0, "TZ="), val);
415 	environ = fakeenv = env;
416 	tzset();
417 	return env;
418 }
419 
420 static void
421 tzfree(timezone_t env)
422 {
423 	environ = env + 1;
424 	free(env[0]);
425 }
426 #endif /* ! USE_LOCALTIME_RZ */
427 
428 /* A UTC time zone, and its initializer.  */
429 static timezone_t gmtz;
430 static void
431 gmtzinit(void)
432 {
433 	if (USE_LOCALTIME_RZ) {
434 		static char const utc[] = "UTC0";
435 		gmtz = tzalloc(utc);
436 		if (!gmtz) {
437 		      err(EXIT_FAILURE, "Cannot create %s", utc);
438 		}
439 	}
440 }
441 
442 /* Convert *TP to UTC, storing the broken-down time into *TMP.
443    Return TMP if successful, NULL otherwise.  This is like gmtime_r(TP, TMP),
444    except typically faster if USE_LOCALTIME_RZ.  */
445 static struct tm *
446 my_gmtime_r(time_t *tp, struct tm *tmp)
447 {
448 	return USE_LOCALTIME_RZ ?
449 	    localtime_rz(gmtz, tp, tmp) : gmtime_r(tp, tmp);
450 }
451 
452 #ifndef TYPECHECK
453 #define my_localtime_rz	localtime_rz
454 #else /* !defined TYPECHECK */
455 static struct tm *
456 my_localtime_rz(timezone_t tz, const time_t *tp, struct tm *tmp)
457 {
458 	tmp = localtime_rz(tz, tp, tmp);
459 	if (tmp) {
460 		struct tm	tm;
461 		time_t	t;
462 
463 		tm = *tmp;
464 		t = mktime_z(tz, &tm);
465 		if (t != *tp) {
466 			(void) fflush(stdout);
467 			(void) fprintf(stderr, "\n%s: ", progname);
468 			(void) fprintf(stderr, tformat(), *tp);
469 			(void) fprintf(stderr, " ->");
470 			(void) fprintf(stderr, " year=%d", tmp->tm_year);
471 			(void) fprintf(stderr, " mon=%d", tmp->tm_mon);
472 			(void) fprintf(stderr, " mday=%d", tmp->tm_mday);
473 			(void) fprintf(stderr, " hour=%d", tmp->tm_hour);
474 			(void) fprintf(stderr, " min=%d", tmp->tm_min);
475 			(void) fprintf(stderr, " sec=%d", tmp->tm_sec);
476 			(void) fprintf(stderr, " isdst=%d", tmp->tm_isdst);
477 			(void) fprintf(stderr, " -> ");
478 			(void) fprintf(stderr, tformat(), t);
479 			(void) fprintf(stderr, "\n");
480 			errout = true;
481 		}
482 	}
483 	return tmp;
484 }
485 #endif /* !defined TYPECHECK */
486 
487 static void
488 abbrok(const char *const abbrp, const char *const zone)
489 {
490 	const char *cp;
491 	const char *wp;
492 
493 	if (warned)
494 		return;
495 	cp = abbrp;
496 	wp = NULL;
497 	while (is_alpha(*cp))
498 		++cp;
499 	if (cp - abbrp == 0)
500 		wp = _("lacks alphabetic at start");
501 	else if (cp - abbrp < 3)
502 		wp = _("has fewer than 3 alphabetics");
503 	else if (cp - abbrp > 6)
504 		wp = _("has more than 6 alphabetics");
505 	if (wp == NULL && (*cp == '+' || *cp == '-')) {
506 		++cp;
507 		if ('0' <= *cp && *cp <= '9')
508 			if (*cp++ == '1' && '0' <= *cp && *cp <= '4')
509 				cp++;
510 		if (*cp != '\0')
511 			wp = _("differs from POSIX standard");
512 	}
513 	if (wp == NULL)
514 		return;
515 	(void) fflush(stdout);
516 	(void) fprintf(stderr,
517 		_("%s: warning: zone \"%s\" abbreviation \"%s\" %s\n"),
518 		progname, zone, abbrp, wp);
519 	warned = errout = true;
520 }
521 
522 /* Return a time zone abbreviation.  If the abbreviation needs to be
523    saved, use *BUF (of size *BUFALLOC) to save it, and return the
524    abbreviation in the possibly-reallocated *BUF.  Otherwise, just
525    return the abbreviation.  Get the abbreviation from TMP.
526    Exit on memory allocation failure.  */
527 static char const *
528 saveabbr(char **buf, size_t *bufalloc, struct tm const *tmp)
529 {
530 	char const *ab = abbr(tmp);
531 	if (HAVE_LOCALTIME_RZ)
532 		return ab;
533 	else {
534 		size_t ablen = strlen(ab);
535 		if (*bufalloc <= ablen) {
536 			free(*buf);
537 
538 			/* Make the new buffer at least twice as long as the
539 			   old, to avoid O(N**2) behavior on repeated calls.  */
540 			*bufalloc = sumsize(*bufalloc, ablen + 1);
541 			*buf = malloc(*bufalloc);
542 			if (! *buf) {
543 				err(EXIT_FAILURE, "malloc");
544 			}
545 		}
546 		return strcpy(*buf, ab);
547 	}
548 }
549 
550 static void
551 close_file(FILE *stream)
552 {
553 	char const *e = (ferror(stream) ? _("I/O error")
554 	    : fclose(stream) != 0 ? strerror(errno) : NULL);
555 	if (e) {
556 		errx(EXIT_FAILURE, "%s", e);
557 	}
558 }
559 
560 __dead static void
561 usage(FILE *const stream, const int status)
562 {
563 	(void) fprintf(stream,
564 _("%s: usage: %s [--version] [--help] [-{vV}] [-{ct} [lo,]hi] zonename ...\n"
565   "\n"
566   "Report bugs to %s.\n"),
567 		       progname, progname, REPORT_BUGS_TO);
568 	if (status == EXIT_SUCCESS)
569 		close_file(stream);
570 	exit(status);
571 }
572 
573 int
574 main(int argc, char *argv[])
575 {
576 	/* These are static so that they're initially zero.  */
577 	static char *		abbrev;
578 	static size_t		abbrevsize;
579 	static struct tm	newtm;
580 
581 	int		i;
582 	bool		vflag;
583 	bool		Vflag;
584 	char *		cutarg;
585 	char *		cuttimes;
586 	time_t		cutlotime;
587 	time_t		cuthitime;
588 	time_t		now;
589 	time_t		t;
590 	time_t		newt;
591 	struct tm	tm;
592 	struct tm *	tmp;
593 	struct tm *	newtmp;
594 
595 	cutlotime = absolute_min_time;
596 	cuthitime = absolute_max_time;
597 #if HAVE_GETTEXT
598 	(void) setlocale(LC_ALL, "");
599 #ifdef TZ_DOMAINDIR
600 	(void) bindtextdomain(TZ_DOMAIN, TZ_DOMAINDIR);
601 #endif /* defined TEXTDOMAINDIR */
602 	(void) textdomain(TZ_DOMAIN);
603 #endif /* HAVE_GETTEXT */
604 	progname = argv[0];
605 	for (i = 1; i < argc; ++i)
606 		if (strcmp(argv[i], "--version") == 0) {
607 			(void) printf("zdump %s%s\n", PKGVERSION, TZVERSION);
608 			return EXIT_SUCCESS;
609 		} else if (strcmp(argv[i], "--help") == 0) {
610 			usage(stdout, EXIT_SUCCESS);
611 		}
612 	vflag = Vflag = false;
613 	cutarg = cuttimes = NULL;
614 	for (;;)
615 	  switch (getopt(argc, argv, "c:t:vV")) {
616 	  case 'c': cutarg = optarg; break;
617 	  case 't': cuttimes = optarg; break;
618 	  case 'v': vflag = true; break;
619 	  case 'V': Vflag = true; break;
620 	  case -1:
621 	    if (! (optind == argc - 1 && strcmp(argv[optind], "=") == 0))
622 	      goto arg_processing_done;
623 	    /* Fall through.  */
624 	  default:
625 	    usage(stderr, EXIT_FAILURE);
626 	  }
627  arg_processing_done:;
628 
629 	if (vflag | Vflag) {
630 		intmax_t	lo;
631 		intmax_t	hi;
632 		char *loend, *hiend;
633 		intmax_t cutloyear = ZDUMP_LO_YEAR;
634 		intmax_t cuthiyear = ZDUMP_HI_YEAR;
635 		if (cutarg != NULL) {
636 			lo = strtoimax(cutarg, &loend, 10);
637 			if (cutarg != loend && !*loend) {
638 				hi = lo;
639 				cuthiyear = hi;
640 			} else if (cutarg != loend && *loend == ','
641 				   && (hi = strtoimax(loend + 1, &hiend, 10),
642 				       loend + 1 != hiend && !*hiend)) {
643 				cutloyear = lo;
644 				cuthiyear = hi;
645 			} else {
646 				fprintf(stderr, _("%s: wild -c argument %s\n"),
647 					progname, cutarg);
648 				return EXIT_FAILURE;
649 			}
650 		}
651 		if (cutarg != NULL || cuttimes == NULL) {
652 			cutlotime = yeartot(cutloyear);
653 			cuthitime = yeartot(cuthiyear);
654 		}
655 		if (cuttimes != NULL) {
656 			lo = strtoimax(cuttimes, &loend, 10);
657 			if (cuttimes != loend && !*loend) {
658 				hi = lo;
659 				if (hi < cuthitime) {
660 					if (hi < absolute_min_time)
661 						hi = absolute_min_time;
662 					cuthitime = hi;
663 				}
664 			} else if (cuttimes != loend && *loend == ','
665 				   && (hi = strtoimax(loend + 1, &hiend, 10),
666 				       loend + 1 != hiend && !*hiend)) {
667 				if (cutlotime < lo) {
668 					if (absolute_max_time < lo)
669 						lo = absolute_max_time;
670 					cutlotime = lo;
671 				}
672 				if (hi < cuthitime) {
673 					if (hi < absolute_min_time)
674 						hi = absolute_min_time;
675 					cuthitime = hi;
676 				}
677 			} else {
678 				(void) fprintf(stderr,
679 					_("%s: wild -t argument %s\n"),
680 					progname, cuttimes);
681 				return EXIT_FAILURE;
682 			}
683 		}
684 	}
685 	gmtzinit();
686 	now = time(NULL);
687 	longest = 0;
688 	for (i = optind; i < argc; i++) {
689 		size_t arglen = strlen(argv[i]);
690 		if (longest < arglen)
691 			longest = arglen < INT_MAX ? arglen : INT_MAX;
692 	}
693 
694 	for (i = optind; i < argc; ++i) {
695 		timezone_t tz = tzalloc(argv[i]);
696 		char const *ab;
697 		if (!tz) {
698 			errx(EXIT_FAILURE, "%s", argv[i]);
699 		}
700 		if (! (vflag | Vflag)) {
701 			show(tz, argv[i], now, false);
702 			tzfree(tz);
703 			continue;
704 		}
705 		warned = false;
706 		t = absolute_min_time;
707 		if (!Vflag) {
708 			show(tz, argv[i], t, true);
709 			t += SECSPERDAY;
710 			show(tz, argv[i], t, true);
711 		}
712 		if (t < cutlotime)
713 			t = cutlotime;
714 		tmp = my_localtime_rz(tz, &t, &tm);
715 		if (tmp)
716 			ab = saveabbr(&abbrev, &abbrevsize, &tm);
717 		else
718 			ab = NULL;
719 		while (t < cuthitime) {
720 			newt = ((t < absolute_max_time - SECSPERDAY / 2
721 				&& t + SECSPERDAY / 2 < cuthitime)
722 				? t + SECSPERDAY / 2
723 				: cuthitime);
724 			newtmp = localtime_rz(tz, &newt, &newtm);
725 			if ((tmp == NULL || newtmp == NULL) ? (tmp != newtmp) :
726 			    (delta(&newtm, &tm) != (newt - t) ||
727 			    newtm.tm_isdst != tm.tm_isdst ||
728 			    strcmp(abbr(&newtm), ab) != 0)) {
729 				newt = hunt(tz, argv[i], t, newt);
730 				newtmp = localtime_rz(tz, &newt, &newtm);
731 				if (newtmp)
732 					  ab = saveabbr(&abbrev, &abbrevsize,
733 							&newtm);
734 			}
735 			t = newt;
736 			tm = newtm;
737 			tmp = newtmp;
738 		}
739 		if (!Vflag) {
740 			t = absolute_max_time;
741 			t -= SECSPERDAY;
742 			show(tz, argv[i], t, true);
743 			t += SECSPERDAY;
744 			show(tz, argv[i], t, true);
745 		}
746 		tzfree(tz);
747 	}
748 	close_file(stdout);
749 	if (errout && (ferror(stderr) || fclose(stderr) != 0))
750 		return EXIT_FAILURE;
751 	return EXIT_SUCCESS;
752 }
753 
754 static time_t
755 yeartot(const intmax_t y)
756 {
757 	intmax_t	myy, seconds, years;
758 	time_t		t;
759 
760 	myy = EPOCH_YEAR;
761 	t = 0;
762 	while (myy < y) {
763 		if (SECSPER400YEARS_FITS && 400 <= y - myy) {
764 			intmax_t diff400 = (y - myy) / 400;
765 			if (INTMAX_MAX / SECSPER400YEARS < diff400)
766 				return absolute_max_time;
767 			seconds = diff400 * SECSPER400YEARS;
768 			years = diff400 * 400;
769                 } else {
770 			seconds = isleap(myy) ? SECSPERLYEAR : SECSPERNYEAR;
771 			years = 1;
772 		}
773 		myy += years;
774 		if (t > absolute_max_time - seconds)
775 			return absolute_max_time;
776 		t += seconds;
777 	}
778 	while (y < myy) {
779 		if (SECSPER400YEARS_FITS && y + 400 <= myy && myy < 0) {
780 			intmax_t diff400 = (myy - y) / 400;
781 			if (INTMAX_MAX / SECSPER400YEARS < diff400)
782 				return absolute_min_time;
783 			seconds = diff400 * SECSPER400YEARS;
784 			years = diff400 * 400;
785 		} else {
786 			seconds = isleap(myy - 1) ? SECSPERLYEAR : SECSPERNYEAR;
787 			years = 1;
788 		}
789 		myy -= years;
790 		if (t < absolute_min_time + seconds)
791 			return absolute_min_time;
792 		t -= seconds;
793 	}
794 	return t;
795 }
796 
797 static time_t
798 hunt(timezone_t tz, char *name, time_t lot, time_t hit)
799 {
800 	static char *		loab;
801 	static size_t		loabsize;
802 	char const *		ab;
803 	time_t			t;
804 	struct tm		lotm;
805 	struct tm *	lotmp;
806 	struct tm		tm;
807 	struct tm *	tmp;
808 
809 	lotmp = my_localtime_rz(tz, &lot, &lotm);
810 	if (lotmp)
811 		ab = saveabbr(&loab, &loabsize, &lotm);
812 	else
813 		ab = NULL;
814 	for ( ; ; ) {
815 		time_t diff = hit - lot;
816 		if (diff < 2)
817 			break;
818 		t = lot;
819 		t += diff / 2;
820 		if (t <= lot)
821 			++t;
822 		else if (t >= hit)
823 			--t;
824 		tmp = my_localtime_rz(tz, &t, &tm);
825 		if ((lotmp == NULL || tmp == NULL) ? (lotmp == tmp) :
826 			(delta(&tm, &lotm) == (t - lot) &&
827 			tm.tm_isdst == lotm.tm_isdst &&
828 			strcmp(abbr(&tm), ab) == 0)) {
829 				lot = t;
830 				lotm = tm;
831 				lotmp = tmp;
832 		} else	hit = t;
833 	}
834 	show(tz, name, lot, true);
835 	show(tz, name, hit, true);
836 	return hit;
837 }
838 
839 /*
840 ** Thanks to Paul Eggert for logic used in delta.
841 */
842 
843 static intmax_t
844 delta(struct tm *newp, struct tm *oldp)
845 {
846 	intmax_t	result;
847 	int		tmy;
848 
849 	if (newp->tm_year < oldp->tm_year)
850 		return -delta(oldp, newp);
851 	result = 0;
852 	for (tmy = oldp->tm_year; tmy < newp->tm_year; ++tmy)
853 		result += DAYSPERNYEAR + isleap_sum(tmy, TM_YEAR_BASE);
854 	result += newp->tm_yday - oldp->tm_yday;
855 	result *= HOURSPERDAY;
856 	result += newp->tm_hour - oldp->tm_hour;
857 	result *= MINSPERHOUR;
858 	result += newp->tm_min - oldp->tm_min;
859 	result *= SECSPERMIN;
860 	result += newp->tm_sec - oldp->tm_sec;
861 	return result;
862 }
863 
864 #ifndef TM_GMTOFF
865 /* Return A->tm_yday, adjusted to compare it fairly to B->tm_yday.
866    Assume A and B differ by at most one year.  */
867 static int
868 adjusted_yday(struct tm const *a, struct tm const *b)
869 {
870 	int yday = a->tm_yday;
871 	if (b->tm_year < a->tm_year)
872 		yday += 365 + isleap_sum(b->tm_year, TM_YEAR_BASE);
873 	return yday;
874 }
875 #endif
876 
877 /* If A is the broken-down local time and B the broken-down UTC for
878    the same instant, return A's UTC offset in seconds, where positive
879    offsets are east of Greenwich.  On failure, return LONG_MIN.  */
880 static long
881 gmtoff(struct tm const *a, struct tm const *b)
882 {
883 #ifdef TM_GMTOFF
884 	return a->TM_GMTOFF;
885 #else
886 	if (! b)
887 		return LONG_MIN;
888 	else {
889 		int ayday = adjusted_yday(a, b);
890 		int byday = adjusted_yday(b, a);
891 		int days = ayday - byday;
892 		long hours = a->tm_hour - b->tm_hour + 24 * days;
893 		long minutes = a->tm_min - b->tm_min + 60 * hours;
894 		long seconds = a->tm_sec - b->tm_sec + 60 * minutes;
895 		return seconds;
896 	}
897 #endif
898 }
899 
900 static void
901 show(timezone_t tz, char *zone, time_t t, bool v)
902 {
903 	struct tm *	tmp;
904 	struct tm *	gmtmp;
905 	struct tm tm, gmtm;
906 
907 	(void) printf("%-*s  ", (int) longest, zone);
908 	if (v) {
909 		gmtmp = my_gmtime_r(&t, &gmtm);
910 		if (gmtmp == NULL) {
911 			printf(tformat(), t);
912 		} else {
913 			dumptime(gmtmp);
914 			(void) printf(" UT");
915 		}
916 		(void) printf(" = ");
917 	}
918 	tmp = my_localtime_rz(tz, &t, &tm);
919 	dumptime(tmp);
920 	if (tmp != NULL) {
921 		if (*abbr(tmp) != '\0')
922 			(void) printf(" %s", abbr(tmp));
923 		if (v) {
924 			long off = gmtoff(tmp, gmtmp);
925 			(void) printf(" isdst=%d", tmp->tm_isdst);
926 			if (off != LONG_MIN)
927 				(void) printf(" gmtoff=%ld", off);
928 		}
929 	}
930 	(void) printf("\n");
931 	if (tmp != NULL && *abbr(tmp) != '\0')
932 		abbrok(abbr(tmp), zone);
933 }
934 
935 static const char *
936 abbr(struct tm const *tmp)
937 {
938 #ifdef TM_ZONE
939 	return tmp->TM_ZONE;
940 #else
941 	return (0 <= tmp->tm_isdst && tzname[0 < tmp->tm_isdst]
942 		? tzname[0 < tmp->tm_isdst]
943 		: "");
944 #endif
945 }
946 
947 /*
948 ** The code below can fail on certain theoretical systems;
949 ** it works on all known real-world systems as of 2004-12-30.
950 */
951 
952 static const char *
953 tformat(void)
954 {
955 	if (0 > (time_t) -1) {		/* signed */
956 		if (sizeof (time_t) == sizeof (intmax_t))
957 			return "%"PRIdMAX;
958 		if (sizeof (time_t) > sizeof (long))
959 			return "%lld";
960 		if (sizeof (time_t) > sizeof (int))
961 			return "%ld";
962 		return "%d";
963 	}
964 #ifdef PRIuMAX
965 	if (sizeof (time_t) == sizeof (uintmax_t))
966 		return "%"PRIuMAX;
967 #endif
968 	if (sizeof (time_t) > sizeof (unsigned long))
969 		return "%llu";
970 	if (sizeof (time_t) > sizeof (unsigned int))
971 		return "%lu";
972 	return "%u";
973 }
974 
975 static void
976 dumptime(const struct tm *timeptr)
977 {
978 	static const char	wday_name[][3] = {
979 		"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
980 	};
981 	static const char	mon_name[][3] = {
982 		"Jan", "Feb", "Mar", "Apr", "May", "Jun",
983 		"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
984 	};
985 	const char *	wn;
986 	const char *	mn;
987 	int		lead;
988 	int		trail;
989 
990 	if (timeptr == NULL) {
991 		printf("NULL");
992 		return;
993 	}
994 	/*
995 	** The packaged localtime_rz and gmtime_r never put out-of-range
996 	** values in tm_wday or tm_mon, but since this code might be compiled
997 	** with other (perhaps experimental) versions, paranoia is in order.
998 	*/
999 	if (timeptr->tm_wday < 0 || timeptr->tm_wday >=
1000 		(int) (sizeof wday_name / sizeof wday_name[0]))
1001 			wn = "???";
1002 	else		wn = wday_name[timeptr->tm_wday];
1003 	if (timeptr->tm_mon < 0 || timeptr->tm_mon >=
1004 		(int) (sizeof mon_name / sizeof mon_name[0]))
1005 			mn = "???";
1006 	else		mn = mon_name[timeptr->tm_mon];
1007 	printf("%.3s %.3s%3d %.2d:%.2d:%.2d ",
1008 		wn, mn,
1009 		timeptr->tm_mday, timeptr->tm_hour,
1010 		timeptr->tm_min, timeptr->tm_sec);
1011 #define DIVISOR	10
1012 	trail = timeptr->tm_year % DIVISOR + TM_YEAR_BASE % DIVISOR;
1013 	lead = timeptr->tm_year / DIVISOR + TM_YEAR_BASE / DIVISOR +
1014 		trail / DIVISOR;
1015 	trail %= DIVISOR;
1016 	if (trail < 0 && lead > 0) {
1017 		trail += DIVISOR;
1018 		--lead;
1019 	} else if (lead < 0 && trail > 0) {
1020 		trail -= DIVISOR;
1021 		++lead;
1022 	}
1023 	if (lead == 0)
1024 		printf("%d", trail);
1025 	else	printf("%d%d", lead, ((trail < 0) ? -trail : trail));
1026 }
1027