xref: /netbsd-src/lib/libc/time/zdump.c (revision 37afb7eb6895c833050f8bfb1d1bb2f99f332539)
1 /*	$NetBSD: zdump.c,v 1.41 2015/06/21 16:06:51 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 1.41 2015/06/21 16:06:51 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 enum { atime_shift = CHAR_BIT * sizeof (time_t) - 2 };
265 static time_t	absolute_min_time =
266   ((time_t) -1 < 0
267     ? (- ((time_t) ~ (time_t) 0 < 0)
268        - (((time_t) 1 << atime_shift) - 1 + ((time_t) 1 << atime_shift)))
269     : 0);
270 static time_t	absolute_max_time =
271   ((time_t) -1 < 0
272     ? (((time_t) 1 << atime_shift) - 1 + ((time_t) 1 << atime_shift))
273    : -1);
274 static size_t	longest;
275 static char *	progname;
276 static bool	warned;
277 static bool	errout;
278 
279 static char const *abbr(struct tm const *);
280 static intmax_t	delta(struct tm *, struct tm *) ATTRIBUTE_PURE;
281 static void dumptime(struct tm const *);
282 static time_t hunt(timezone_t, char *, time_t, time_t);
283 static void show(timezone_t, char *, time_t, bool);
284 static const char *tformat(void);
285 static time_t yeartot(intmax_t) ATTRIBUTE_PURE;
286 
287 /* Is A an alphabetic character in the C locale?  */
288 static bool
289 is_alpha(char a)
290 {
291 	switch (a) {
292 	  default:
293 		return false;
294 	  case 'A': case 'B': case 'C': case 'D': case 'E': case 'F': case 'G':
295 	  case 'H': case 'I': case 'J': case 'K': case 'L': case 'M': case 'N':
296 	  case 'O': case 'P': case 'Q': case 'R': case 'S': case 'T': case 'U':
297 	  case 'V': case 'W': case 'X': case 'Y': case 'Z':
298 	  case 'a': case 'b': case 'c': case 'd': case 'e': case 'f': case 'g':
299 	  case 'h': case 'i': case 'j': case 'k': case 'l': case 'm': case 'n':
300 	  case 'o': case 'p': case 'q': case 'r': case 's': case 't': case 'u':
301 	  case 'v': case 'w': case 'x': case 'y': case 'z':
302 	  	return true;
303 	}
304 }
305 
306 /* Return A + B, exiting if the result would overflow.  */
307 static size_t
308 sumsize(size_t a, size_t b)
309 {
310 	size_t sum = a + b;
311 	if (sum < a)
312 		errx(EXIT_FAILURE, "size overflow");
313 	return sum;
314 }
315 
316 #if ! HAVE_TZSET
317 # undef tzset
318 # define tzset zdump_tzset
319 static void tzset(void) { }
320 #endif
321 
322 /* Assume gmtime_r works if localtime_r does.
323    A replacement localtime_r is defined below if needed.  */
324 #if ! HAVE_LOCALTIME_R
325 
326 # undef gmtime_r
327 # define gmtime_r zdump_gmtime_r
328 
329 static struct tm *
330 gmtime_r(time_t *tp, struct tm *tmp)
331 {
332 	struct tm *r = gmtime(tp);
333 	if (r) {
334 		*tmp = *r;
335 		r = tmp;
336 	}
337 	return r;
338 }
339 
340 #endif
341 
342 /* Platforms with TM_ZONE don't need tzname, so they can use the
343    faster localtime_rz or localtime_r if available.  */
344 
345 #if defined TM_ZONE && HAVE_LOCALTIME_RZ
346 # define USE_LOCALTIME_RZ true
347 #else
348 # define USE_LOCALTIME_RZ false
349 #endif
350 
351 #if ! USE_LOCALTIME_RZ
352 
353 # if !defined TM_ZONE || ! HAVE_LOCALTIME_R || ! HAVE_TZSET
354 #  undef localtime_r
355 #  define localtime_r zdump_localtime_r
356 static struct tm *
357 localtime_r(time_t *tp, struct tm *tmp)
358 {
359 	struct tm *r = localtime(tp);
360 	if (r) {
361 		*tmp = *r;
362 		r = tmp;
363 	}
364 	return r;
365 }
366 # endif
367 
368 # undef localtime_rz
369 # define localtime_rz zdump_localtime_rz
370 static struct tm *
371 localtime_rz(timezone_t rz, time_t *tp, struct tm *tmp)
372 {
373 	return localtime_r(tp, tmp);
374 }
375 
376 # ifdef TYPECHECK
377 #  undef mktime_z
378 #  define mktime_z zdump_mktime_z
379 static time_t
380 mktime_z(timezone_t tz, struct tm *tmp)
381 {
382 	return mktime(tmp);
383 }
384 # endif
385 
386 # undef tzalloc
387 # undef tzfree
388 # define tzalloc zdump_tzalloc
389 # define tzfree zdump_tzfree
390 
391 static timezone_t
392 tzalloc(char const *val)
393 {
394 	static char **fakeenv;
395 	char **env = fakeenv;
396 	char *env0;
397 	if (! env) {
398 		char **e = environ;
399 		int to;
400 
401 		while (*e++)
402 			continue;
403 		env = malloc(sumsize(sizeof *environ,
404 		    (e - environ) * sizeof *environ));
405 		if (! env) {
406 			err(EXIT_FAILURE, "malloc");
407 		}
408 		to = 1;
409 		for (e = environ; (env[to] = *e); e++)
410 			to += strncmp(*e, "TZ=", 3) != 0;
411 	}
412 	env0 = malloc(sumsize(sizeof "TZ=", strlen(val)));
413 	if (! env0) {
414 		err(EXIT_FAILURE, "malloc");
415 	}
416 	env[0] = strcat(strcpy(env0, "TZ="), val);
417 	environ = fakeenv = env;
418 	tzset();
419 	return env;
420 }
421 
422 static void
423 tzfree(timezone_t env)
424 {
425 	environ = env + 1;
426 	free(env[0]);
427 }
428 #endif /* ! USE_LOCALTIME_RZ */
429 
430 /* A UTC time zone, and its initializer.  */
431 static timezone_t gmtz;
432 static void
433 gmtzinit(void)
434 {
435 	if (USE_LOCALTIME_RZ) {
436 		static char const utc[] = "UTC0";
437 		gmtz = tzalloc(utc);
438 		if (!gmtz) {
439 		      err(EXIT_FAILURE, "Cannot create %s", utc);
440 		}
441 	}
442 }
443 
444 /* Convert *TP to UTC, storing the broken-down time into *TMP.
445    Return TMP if successful, NULL otherwise.  This is like gmtime_r(TP, TMP),
446    except typically faster if USE_LOCALTIME_RZ.  */
447 static struct tm *
448 my_gmtime_r(time_t *tp, struct tm *tmp)
449 {
450 	return USE_LOCALTIME_RZ ?
451 	    localtime_rz(gmtz, tp, tmp) : gmtime_r(tp, tmp);
452 }
453 
454 #ifndef TYPECHECK
455 #define my_localtime_rz	localtime_rz
456 #else /* !defined TYPECHECK */
457 static struct tm *
458 my_localtime_rz(timezone_t tz, const time_t *tp, struct tm *tmp)
459 {
460 	tmp = localtime_rz(tz, tp, tmp);
461 	if (tmp) {
462 		struct tm	tm;
463 		time_t	t;
464 
465 		tm = *tmp;
466 		t = mktime_z(tz, &tm);
467 		if (t != *tp) {
468 			(void) fflush(stdout);
469 			(void) fprintf(stderr, "\n%s: ", progname);
470 			(void) fprintf(stderr, tformat(), *tp);
471 			(void) fprintf(stderr, " ->");
472 			(void) fprintf(stderr, " year=%d", tmp->tm_year);
473 			(void) fprintf(stderr, " mon=%d", tmp->tm_mon);
474 			(void) fprintf(stderr, " mday=%d", tmp->tm_mday);
475 			(void) fprintf(stderr, " hour=%d", tmp->tm_hour);
476 			(void) fprintf(stderr, " min=%d", tmp->tm_min);
477 			(void) fprintf(stderr, " sec=%d", tmp->tm_sec);
478 			(void) fprintf(stderr, " isdst=%d", tmp->tm_isdst);
479 			(void) fprintf(stderr, " -> ");
480 			(void) fprintf(stderr, tformat(), t);
481 			(void) fprintf(stderr, "\n");
482 			errout = true;
483 		}
484 	}
485 	return tmp;
486 }
487 #endif /* !defined TYPECHECK */
488 
489 static void
490 abbrok(const char *const abbrp, const char *const zone)
491 {
492 	const char *cp;
493 	const char *wp;
494 
495 	if (warned)
496 		return;
497 	cp = abbrp;
498 	wp = NULL;
499 	while (is_alpha(*cp))
500 		++cp;
501 	if (cp - abbrp == 0)
502 		wp = _("lacks alphabetic at start");
503 	else if (cp - abbrp < 3)
504 		wp = _("has fewer than 3 alphabetics");
505 	else if (cp - abbrp > 6)
506 		wp = _("has more than 6 alphabetics");
507 	if (wp == NULL && (*cp == '+' || *cp == '-')) {
508 		++cp;
509 		if ('0' <= *cp && *cp <= '9')
510 			if (*cp++ == '1' && '0' <= *cp && *cp <= '4')
511 				cp++;
512 		if (*cp != '\0')
513 			wp = _("differs from POSIX standard");
514 	}
515 	if (wp == NULL)
516 		return;
517 	(void) fflush(stdout);
518 	(void) fprintf(stderr,
519 		_("%s: warning: zone \"%s\" abbreviation \"%s\" %s\n"),
520 		progname, zone, abbrp, wp);
521 	warned = errout = true;
522 }
523 
524 /* Return a time zone abbreviation.  If the abbreviation needs to be
525    saved, use *BUF (of size *BUFALLOC) to save it, and return the
526    abbreviation in the possibly-reallocated *BUF.  Otherwise, just
527    return the abbreviation.  Get the abbreviation from TMP.
528    Exit on memory allocation failure.  */
529 static char const *
530 saveabbr(char **buf, size_t *bufalloc, struct tm const *tmp)
531 {
532 	char const *ab = abbr(tmp);
533 	if (HAVE_LOCALTIME_RZ)
534 		return ab;
535 	else {
536 		size_t ablen = strlen(ab);
537 		if (*bufalloc <= ablen) {
538 			free(*buf);
539 
540 			/* Make the new buffer at least twice as long as the
541 			   old, to avoid O(N**2) behavior on repeated calls.  */
542 			*bufalloc = sumsize(*bufalloc, ablen + 1);
543 			*buf = malloc(*bufalloc);
544 			if (! *buf) {
545 				err(EXIT_FAILURE, "malloc");
546 			}
547 		}
548 		return strcpy(*buf, ab);
549 	}
550 }
551 
552 static void
553 close_file(FILE *stream)
554 {
555 	char const *e = (ferror(stream) ? _("I/O error")
556 	    : fclose(stream) != 0 ? strerror(errno) : NULL);
557 	if (e) {
558 		errx(EXIT_FAILURE, "%s", e);
559 	}
560 }
561 
562 __dead static void
563 usage(FILE *const stream, const int status)
564 {
565 	(void) fprintf(stream,
566 _("%s: usage: %s [--version] [--help] [-{vV}] [-{ct} [lo,]hi] zonename ...\n"
567   "\n"
568   "Report bugs to %s.\n"),
569 		       progname, progname, REPORT_BUGS_TO);
570 	if (status == EXIT_SUCCESS)
571 		close_file(stream);
572 	exit(status);
573 }
574 
575 int
576 main(int argc, char *argv[])
577 {
578 	/* These are static so that they're initially zero.  */
579 	static char *		abbrev;
580 	static size_t		abbrevsize;
581 	static struct tm	newtm;
582 
583 	int		i;
584 	bool		vflag;
585 	bool		Vflag;
586 	char *		cutarg;
587 	char *		cuttimes;
588 	time_t		cutlotime;
589 	time_t		cuthitime;
590 	time_t		now;
591 	time_t		t;
592 	time_t		newt;
593 	struct tm	tm;
594 	struct tm *	tmp;
595 	struct tm *	newtmp;
596 
597 	cutlotime = absolute_min_time;
598 	cuthitime = absolute_max_time;
599 #if HAVE_GETTEXT
600 	(void) setlocale(LC_ALL, "");
601 #ifdef TZ_DOMAINDIR
602 	(void) bindtextdomain(TZ_DOMAIN, TZ_DOMAINDIR);
603 #endif /* defined TEXTDOMAINDIR */
604 	(void) textdomain(TZ_DOMAIN);
605 #endif /* HAVE_GETTEXT */
606 	progname = argv[0];
607 	for (i = 1; i < argc; ++i)
608 		if (strcmp(argv[i], "--version") == 0) {
609 			(void) printf("zdump %s%s\n", PKGVERSION, TZVERSION);
610 			return EXIT_SUCCESS;
611 		} else if (strcmp(argv[i], "--help") == 0) {
612 			usage(stdout, EXIT_SUCCESS);
613 		}
614 	vflag = Vflag = false;
615 	cutarg = cuttimes = NULL;
616 	for (;;)
617 	  switch (getopt(argc, argv, "c:t:vV")) {
618 	  case 'c': cutarg = optarg; break;
619 	  case 't': cuttimes = optarg; break;
620 	  case 'v': vflag = true; break;
621 	  case 'V': Vflag = true; break;
622 	  case -1:
623 	    if (! (optind == argc - 1 && strcmp(argv[optind], "=") == 0))
624 	      goto arg_processing_done;
625 	    /* Fall through.  */
626 	  default:
627 	    usage(stderr, EXIT_FAILURE);
628 	  }
629  arg_processing_done:;
630 
631 	if (vflag | Vflag) {
632 		intmax_t	lo;
633 		intmax_t	hi;
634 		char *loend, *hiend;
635 		intmax_t cutloyear = ZDUMP_LO_YEAR;
636 		intmax_t cuthiyear = ZDUMP_HI_YEAR;
637 		if (cutarg != NULL) {
638 			lo = strtoimax(cutarg, &loend, 10);
639 			if (cutarg != loend && !*loend) {
640 				hi = lo;
641 				cuthiyear = hi;
642 			} else if (cutarg != loend && *loend == ','
643 				   && (hi = strtoimax(loend + 1, &hiend, 10),
644 				       loend + 1 != hiend && !*hiend)) {
645 				cutloyear = lo;
646 				cuthiyear = hi;
647 			} else {
648 				fprintf(stderr, _("%s: wild -c argument %s\n"),
649 					progname, cutarg);
650 				return EXIT_FAILURE;
651 			}
652 		}
653 		if (cutarg != NULL || cuttimes == NULL) {
654 			cutlotime = yeartot(cutloyear);
655 			cuthitime = yeartot(cuthiyear);
656 		}
657 		if (cuttimes != NULL) {
658 			lo = strtoimax(cuttimes, &loend, 10);
659 			if (cuttimes != loend && !*loend) {
660 				hi = lo;
661 				if (hi < cuthitime) {
662 					if (hi < absolute_min_time)
663 						hi = absolute_min_time;
664 					cuthitime = hi;
665 				}
666 			} else if (cuttimes != loend && *loend == ','
667 				   && (hi = strtoimax(loend + 1, &hiend, 10),
668 				       loend + 1 != hiend && !*hiend)) {
669 				if (cutlotime < lo) {
670 					if (absolute_max_time < lo)
671 						lo = absolute_max_time;
672 					cutlotime = lo;
673 				}
674 				if (hi < cuthitime) {
675 					if (hi < absolute_min_time)
676 						hi = absolute_min_time;
677 					cuthitime = hi;
678 				}
679 			} else {
680 				(void) fprintf(stderr,
681 					_("%s: wild -t argument %s\n"),
682 					progname, cuttimes);
683 				return EXIT_FAILURE;
684 			}
685 		}
686 	}
687 	gmtzinit();
688 	now = time(NULL);
689 	longest = 0;
690 	for (i = optind; i < argc; i++) {
691 		size_t arglen = strlen(argv[i]);
692 		if (longest < arglen)
693 			longest = arglen < INT_MAX ? arglen : INT_MAX;
694 	}
695 
696 	for (i = optind; i < argc; ++i) {
697 		timezone_t tz = tzalloc(argv[i]);
698 		char const *ab;
699 		if (!tz) {
700 			errx(EXIT_FAILURE, "%s", argv[i]);
701 		}
702 		if (! (vflag | Vflag)) {
703 			show(tz, argv[i], now, false);
704 			tzfree(tz);
705 			continue;
706 		}
707 		warned = false;
708 		t = absolute_min_time;
709 		if (!Vflag) {
710 			show(tz, argv[i], t, true);
711 			t += SECSPERDAY;
712 			show(tz, argv[i], t, true);
713 		}
714 		if (t < cutlotime)
715 			t = cutlotime;
716 		tmp = my_localtime_rz(tz, &t, &tm);
717 		if (tmp)
718 			ab = saveabbr(&abbrev, &abbrevsize, &tm);
719 		else
720 			ab = NULL;
721 		while (t < cuthitime) {
722 			newt = ((t < absolute_max_time - SECSPERDAY / 2
723 				&& t + SECSPERDAY / 2 < cuthitime)
724 				? t + SECSPERDAY / 2
725 				: cuthitime);
726 			newtmp = localtime_rz(tz, &newt, &newtm);
727 			if ((tmp == NULL || newtmp == NULL) ? (tmp != newtmp) :
728 			    (delta(&newtm, &tm) != (newt - t) ||
729 			    newtm.tm_isdst != tm.tm_isdst ||
730 			    strcmp(abbr(&newtm), ab) != 0)) {
731 				newt = hunt(tz, argv[i], t, newt);
732 				newtmp = localtime_rz(tz, &newt, &newtm);
733 				if (newtmp)
734 					  ab = saveabbr(&abbrev, &abbrevsize,
735 							&newtm);
736 			}
737 			t = newt;
738 			tm = newtm;
739 			tmp = newtmp;
740 		}
741 		if (!Vflag) {
742 			t = absolute_max_time;
743 			t -= SECSPERDAY;
744 			show(tz, argv[i], t, true);
745 			t += SECSPERDAY;
746 			show(tz, argv[i], t, true);
747 		}
748 		tzfree(tz);
749 	}
750 	close_file(stdout);
751 	if (errout && (ferror(stderr) || fclose(stderr) != 0))
752 		return EXIT_FAILURE;
753 	return EXIT_SUCCESS;
754 }
755 
756 static time_t
757 yeartot(const intmax_t y)
758 {
759 	intmax_t	myy, seconds, years;
760 	time_t		t;
761 
762 	myy = EPOCH_YEAR;
763 	t = 0;
764 	while (myy < y) {
765 		if (SECSPER400YEARS_FITS && 400 <= y - myy) {
766 			intmax_t diff400 = (y - myy) / 400;
767 			if (INTMAX_MAX / SECSPER400YEARS < diff400)
768 				return absolute_max_time;
769 			seconds = diff400 * SECSPER400YEARS;
770 			years = diff400 * 400;
771                 } else {
772 			seconds = isleap(myy) ? SECSPERLYEAR : SECSPERNYEAR;
773 			years = 1;
774 		}
775 		myy += years;
776 		if (t > absolute_max_time - seconds)
777 			return absolute_max_time;
778 		t += seconds;
779 	}
780 	while (y < myy) {
781 		if (SECSPER400YEARS_FITS && y + 400 <= myy && myy < 0) {
782 			intmax_t diff400 = (myy - y) / 400;
783 			if (INTMAX_MAX / SECSPER400YEARS < diff400)
784 				return absolute_min_time;
785 			seconds = diff400 * SECSPER400YEARS;
786 			years = diff400 * 400;
787 		} else {
788 			seconds = isleap(myy - 1) ? SECSPERLYEAR : SECSPERNYEAR;
789 			years = 1;
790 		}
791 		myy -= years;
792 		if (t < absolute_min_time + seconds)
793 			return absolute_min_time;
794 		t -= seconds;
795 	}
796 	return t;
797 }
798 
799 static time_t
800 hunt(timezone_t tz, char *name, time_t lot, time_t hit)
801 {
802 	static char *		loab;
803 	static size_t		loabsize;
804 	char const *		ab;
805 	time_t			t;
806 	struct tm		lotm;
807 	struct tm *	lotmp;
808 	struct tm		tm;
809 	struct tm *	tmp;
810 
811 	lotmp = my_localtime_rz(tz, &lot, &lotm);
812 	if (lotmp)
813 		ab = saveabbr(&loab, &loabsize, &lotm);
814 	else
815 		ab = NULL;
816 	for ( ; ; ) {
817 		time_t diff = hit - lot;
818 		if (diff < 2)
819 			break;
820 		t = lot;
821 		t += diff / 2;
822 		if (t <= lot)
823 			++t;
824 		else if (t >= hit)
825 			--t;
826 		tmp = my_localtime_rz(tz, &t, &tm);
827 		if ((lotmp == NULL || tmp == NULL) ? (lotmp == tmp) :
828 			(delta(&tm, &lotm) == (t - lot) &&
829 			tm.tm_isdst == lotm.tm_isdst &&
830 			strcmp(abbr(&tm), ab) == 0)) {
831 				lot = t;
832 				lotm = tm;
833 				lotmp = tmp;
834 		} else	hit = t;
835 	}
836 	show(tz, name, lot, true);
837 	show(tz, name, hit, true);
838 	return hit;
839 }
840 
841 /*
842 ** Thanks to Paul Eggert for logic used in delta.
843 */
844 
845 static intmax_t
846 delta(struct tm *newp, struct tm *oldp)
847 {
848 	intmax_t	result;
849 	int		tmy;
850 
851 	if (newp->tm_year < oldp->tm_year)
852 		return -delta(oldp, newp);
853 	result = 0;
854 	for (tmy = oldp->tm_year; tmy < newp->tm_year; ++tmy)
855 		result += DAYSPERNYEAR + isleap_sum(tmy, TM_YEAR_BASE);
856 	result += newp->tm_yday - oldp->tm_yday;
857 	result *= HOURSPERDAY;
858 	result += newp->tm_hour - oldp->tm_hour;
859 	result *= MINSPERHOUR;
860 	result += newp->tm_min - oldp->tm_min;
861 	result *= SECSPERMIN;
862 	result += newp->tm_sec - oldp->tm_sec;
863 	return result;
864 }
865 
866 #ifndef TM_GMTOFF
867 /* Return A->tm_yday, adjusted to compare it fairly to B->tm_yday.
868    Assume A and B differ by at most one year.  */
869 static int
870 adjusted_yday(struct tm const *a, struct tm const *b)
871 {
872 	int yday = a->tm_yday;
873 	if (b->tm_year < a->tm_year)
874 		yday += 365 + isleap_sum(b->tm_year, TM_YEAR_BASE);
875 	return yday;
876 }
877 #endif
878 
879 /* If A is the broken-down local time and B the broken-down UTC for
880    the same instant, return A's UTC offset in seconds, where positive
881    offsets are east of Greenwich.  On failure, return LONG_MIN.  */
882 static long
883 gmtoff(struct tm const *a, struct tm const *b)
884 {
885 #ifdef TM_GMTOFF
886 	return a->TM_GMTOFF;
887 #else
888 	if (! b)
889 		return LONG_MIN;
890 	else {
891 		int ayday = adjusted_yday(a, b);
892 		int byday = adjusted_yday(b, a);
893 		int days = ayday - byday;
894 		long hours = a->tm_hour - b->tm_hour + 24 * days;
895 		long minutes = a->tm_min - b->tm_min + 60 * hours;
896 		long seconds = a->tm_sec - b->tm_sec + 60 * minutes;
897 		return seconds;
898 	}
899 #endif
900 }
901 
902 static void
903 show(timezone_t tz, char *zone, time_t t, bool v)
904 {
905 	struct tm *	tmp;
906 	struct tm *	gmtmp;
907 	struct tm tm, gmtm;
908 
909 	(void) printf("%-*s  ", (int) longest, zone);
910 	if (v) {
911 		gmtmp = my_gmtime_r(&t, &gmtm);
912 		if (gmtmp == NULL) {
913 			printf(tformat(), t);
914 		} else {
915 			dumptime(gmtmp);
916 			(void) printf(" UT");
917 		}
918 		(void) printf(" = ");
919 	}
920 	tmp = my_localtime_rz(tz, &t, &tm);
921 	dumptime(tmp);
922 	if (tmp != NULL) {
923 		if (*abbr(tmp) != '\0')
924 			(void) printf(" %s", abbr(tmp));
925 		if (v) {
926 			long off = gmtoff(tmp, gmtmp);
927 			(void) printf(" isdst=%d", tmp->tm_isdst);
928 			if (off != LONG_MIN)
929 				(void) printf(" gmtoff=%ld", off);
930 		}
931 	}
932 	(void) printf("\n");
933 	if (tmp != NULL && *abbr(tmp) != '\0')
934 		abbrok(abbr(tmp), zone);
935 }
936 
937 static const char *
938 abbr(struct tm const *tmp)
939 {
940 #ifdef TM_ZONE
941 	return tmp->TM_ZONE;
942 #else
943 	return (0 <= tmp->tm_isdst && tzname[0 < tmp->tm_isdst]
944 		? tzname[0 < tmp->tm_isdst]
945 		: "");
946 #endif
947 }
948 
949 /*
950 ** The code below can fail on certain theoretical systems;
951 ** it works on all known real-world systems as of 2004-12-30.
952 */
953 
954 static const char *
955 tformat(void)
956 {
957 	if (0 > (time_t) -1) {		/* signed */
958 		if (sizeof (time_t) == sizeof (intmax_t))
959 			return "%"PRIdMAX;
960 		if (sizeof (time_t) > sizeof (long))
961 			return "%lld";
962 		if (sizeof (time_t) > sizeof (int))
963 			return "%ld";
964 		return "%d";
965 	}
966 #ifdef PRIuMAX
967 	if (sizeof (time_t) == sizeof (uintmax_t))
968 		return "%"PRIuMAX;
969 #endif
970 	if (sizeof (time_t) > sizeof (unsigned long))
971 		return "%llu";
972 	if (sizeof (time_t) > sizeof (unsigned int))
973 		return "%lu";
974 	return "%u";
975 }
976 
977 static void
978 dumptime(const struct tm *timeptr)
979 {
980 	static const char	wday_name[][3] = {
981 		"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
982 	};
983 	static const char	mon_name[][3] = {
984 		"Jan", "Feb", "Mar", "Apr", "May", "Jun",
985 		"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
986 	};
987 	const char *	wn;
988 	const char *	mn;
989 	int		lead;
990 	int		trail;
991 
992 	if (timeptr == NULL) {
993 		printf("NULL");
994 		return;
995 	}
996 	/*
997 	** The packaged localtime_rz and gmtime_r never put out-of-range
998 	** values in tm_wday or tm_mon, but since this code might be compiled
999 	** with other (perhaps experimental) versions, paranoia is in order.
1000 	*/
1001 	if (timeptr->tm_wday < 0 || timeptr->tm_wday >=
1002 		(int) (sizeof wday_name / sizeof wday_name[0]))
1003 			wn = "???";
1004 	else		wn = wday_name[timeptr->tm_wday];
1005 	if (timeptr->tm_mon < 0 || timeptr->tm_mon >=
1006 		(int) (sizeof mon_name / sizeof mon_name[0]))
1007 			mn = "???";
1008 	else		mn = mon_name[timeptr->tm_mon];
1009 	printf("%.3s %.3s%3d %.2d:%.2d:%.2d ",
1010 		wn, mn,
1011 		timeptr->tm_mday, timeptr->tm_hour,
1012 		timeptr->tm_min, timeptr->tm_sec);
1013 #define DIVISOR	10
1014 	trail = timeptr->tm_year % DIVISOR + TM_YEAR_BASE % DIVISOR;
1015 	lead = timeptr->tm_year / DIVISOR + TM_YEAR_BASE / DIVISOR +
1016 		trail / DIVISOR;
1017 	trail %= DIVISOR;
1018 	if (trail < 0 && lead > 0) {
1019 		trail += DIVISOR;
1020 		--lead;
1021 	} else if (lead < 0 && trail > 0) {
1022 		trail -= DIVISOR;
1023 		++lead;
1024 	}
1025 	if (lead == 0)
1026 		printf("%d", trail);
1027 	else	printf("%d%d", lead, ((trail < 0) ? -trail : trail));
1028 }
1029