xref: /netbsd-src/lib/libc/time/zdump.c (revision 92e958de60c71aa0f2452bd7074cbb006fe6546b)
1 /*	$NetBSD: zdump.c,v 1.43 2016/03/15 15:16:01 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 1.43 2016/03/15 15:16:01 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 #if !HAVE_POSIX_DECLS
258 extern char **	environ;
259 extern int	getopt(int argc, char * const argv[],
260 			const char * options);
261 extern char *	optarg;
262 extern int	optind;
263 extern char *	tzname[];
264 #endif
265 
266 /* The minimum and maximum finite time values.  */
267 enum { atime_shift = CHAR_BIT * sizeof (time_t) - 2 };
268 static time_t	absolute_min_time =
269   ((time_t) -1 < 0
270     ? (- ((time_t) ~ (time_t) 0 < 0)
271        - (((time_t) 1 << atime_shift) - 1 + ((time_t) 1 << atime_shift)))
272     : 0);
273 static time_t	absolute_max_time =
274   ((time_t) -1 < 0
275     ? (((time_t) 1 << atime_shift) - 1 + ((time_t) 1 << atime_shift))
276    : -1);
277 static size_t	longest;
278 static char *	progname;
279 static bool	warned;
280 static bool	errout;
281 
282 static char const *abbr(struct tm const *);
283 static intmax_t	delta(struct tm *, struct tm *) ATTRIBUTE_PURE;
284 static void dumptime(struct tm const *);
285 static time_t hunt(timezone_t, char *, time_t, time_t);
286 static void show(timezone_t, char *, time_t, bool);
287 static const char *tformat(void);
288 static time_t yeartot(intmax_t) ATTRIBUTE_PURE;
289 
290 /* Unlike <ctype.h>'s isdigit, this also works if c < 0 | c > UCHAR_MAX. */
291 #define is_digit(c) ((unsigned)(c) - '0' <= 9)
292 
293 /* Is A an alphabetic character in the C locale?  */
294 static bool
295 is_alpha(char a)
296 {
297 	switch (a) {
298 	  default:
299 		return false;
300 	  case 'A': case 'B': case 'C': case 'D': case 'E': case 'F': case 'G':
301 	  case 'H': case 'I': case 'J': case 'K': case 'L': case 'M': case 'N':
302 	  case 'O': case 'P': case 'Q': case 'R': case 'S': case 'T': case 'U':
303 	  case 'V': case 'W': case 'X': case 'Y': case 'Z':
304 	  case 'a': case 'b': case 'c': case 'd': case 'e': case 'f': case 'g':
305 	  case 'h': case 'i': case 'j': case 'k': case 'l': case 'm': case 'n':
306 	  case 'o': case 'p': case 'q': case 'r': case 's': case 't': case 'u':
307 	  case 'v': case 'w': case 'x': case 'y': case 'z':
308 	  	return true;
309 	}
310 }
311 
312 /* Return A + B, exiting if the result would overflow.  */
313 static size_t
314 sumsize(size_t a, size_t b)
315 {
316 	size_t sum = a + b;
317 	if (sum < a)
318 		errx(EXIT_FAILURE, "size overflow");
319 	return sum;
320 }
321 
322 #if ! HAVE_TZSET
323 # undef tzset
324 # define tzset zdump_tzset
325 static void tzset(void) { }
326 #endif
327 
328 /* Assume gmtime_r works if localtime_r does.
329    A replacement localtime_r is defined below if needed.  */
330 #if ! HAVE_LOCALTIME_R
331 
332 # undef gmtime_r
333 # define gmtime_r zdump_gmtime_r
334 
335 static struct tm *
336 gmtime_r(time_t *tp, struct tm *tmp)
337 {
338 	struct tm *r = gmtime(tp);
339 	if (r) {
340 		*tmp = *r;
341 		r = tmp;
342 	}
343 	return r;
344 }
345 
346 #endif
347 
348 /* Platforms with TM_ZONE don't need tzname, so they can use the
349    faster localtime_rz or localtime_r if available.  */
350 
351 #if defined TM_ZONE && HAVE_LOCALTIME_RZ
352 # define USE_LOCALTIME_RZ true
353 #else
354 # define USE_LOCALTIME_RZ false
355 #endif
356 
357 #if ! USE_LOCALTIME_RZ
358 
359 # if !defined TM_ZONE || ! HAVE_LOCALTIME_R || ! HAVE_TZSET
360 #  undef localtime_r
361 #  define localtime_r zdump_localtime_r
362 static struct tm *
363 localtime_r(time_t *tp, struct tm *tmp)
364 {
365 	struct tm *r = localtime(tp);
366 	if (r) {
367 		*tmp = *r;
368 		r = tmp;
369 	}
370 	return r;
371 }
372 # endif
373 
374 # undef localtime_rz
375 # define localtime_rz zdump_localtime_rz
376 static struct tm *
377 localtime_rz(timezone_t rz, time_t *tp, struct tm *tmp)
378 {
379 	return localtime_r(tp, tmp);
380 }
381 
382 # ifdef TYPECHECK
383 #  undef mktime_z
384 #  define mktime_z zdump_mktime_z
385 static time_t
386 mktime_z(timezone_t tz, struct tm *tmp)
387 {
388 	return mktime(tmp);
389 }
390 # endif
391 
392 # undef tzalloc
393 # undef tzfree
394 # define tzalloc zdump_tzalloc
395 # define tzfree zdump_tzfree
396 
397 static timezone_t
398 tzalloc(char const *val)
399 {
400 	static char **fakeenv;
401 	char **env = fakeenv;
402 	char *env0;
403 	if (! env) {
404 		char **e = environ;
405 		int to;
406 
407 		while (*e++)
408 			continue;
409 		env = malloc(sumsize(sizeof *environ,
410 		    (e - environ) * sizeof *environ));
411 		if (! env) {
412 			err(EXIT_FAILURE, "malloc");
413 		}
414 		to = 1;
415 		for (e = environ; (env[to] = *e); e++)
416 			to += strncmp(*e, "TZ=", 3) != 0;
417 	}
418 	env0 = malloc(sumsize(sizeof "TZ=", strlen(val)));
419 	if (! env0) {
420 		err(EXIT_FAILURE, "malloc");
421 	}
422 	env[0] = strcat(strcpy(env0, "TZ="), val);
423 	environ = fakeenv = env;
424 	tzset();
425 	return env;
426 }
427 
428 static void
429 tzfree(timezone_t env)
430 {
431 	environ = env + 1;
432 	free(env[0]);
433 }
434 #endif /* ! USE_LOCALTIME_RZ */
435 
436 /* A UTC time zone, and its initializer.  */
437 static timezone_t gmtz;
438 static void
439 gmtzinit(void)
440 {
441 	if (USE_LOCALTIME_RZ) {
442 		static char const utc[] = "UTC0";
443 		gmtz = tzalloc(utc);
444 		if (!gmtz) {
445 		      err(EXIT_FAILURE, "Cannot create %s", utc);
446 		}
447 	}
448 }
449 
450 /* Convert *TP to UTC, storing the broken-down time into *TMP.
451    Return TMP if successful, NULL otherwise.  This is like gmtime_r(TP, TMP),
452    except typically faster if USE_LOCALTIME_RZ.  */
453 static struct tm *
454 my_gmtime_r(time_t *tp, struct tm *tmp)
455 {
456 	return USE_LOCALTIME_RZ ?
457 	    localtime_rz(gmtz, tp, tmp) : gmtime_r(tp, tmp);
458 }
459 
460 #ifndef TYPECHECK
461 #define my_localtime_rz	localtime_rz
462 #else /* !defined TYPECHECK */
463 static struct tm *
464 my_localtime_rz(timezone_t tz, const time_t *tp, struct tm *tmp)
465 {
466 	tmp = localtime_rz(tz, tp, tmp);
467 	if (tmp) {
468 		struct tm	tm;
469 		time_t	t;
470 
471 		tm = *tmp;
472 		t = mktime_z(tz, &tm);
473 		if (t != *tp) {
474 			(void) fflush(stdout);
475 			(void) fprintf(stderr, "\n%s: ", progname);
476 			(void) fprintf(stderr, tformat(), *tp);
477 			(void) fprintf(stderr, " ->");
478 			(void) fprintf(stderr, " year=%d", tmp->tm_year);
479 			(void) fprintf(stderr, " mon=%d", tmp->tm_mon);
480 			(void) fprintf(stderr, " mday=%d", tmp->tm_mday);
481 			(void) fprintf(stderr, " hour=%d", tmp->tm_hour);
482 			(void) fprintf(stderr, " min=%d", tmp->tm_min);
483 			(void) fprintf(stderr, " sec=%d", tmp->tm_sec);
484 			(void) fprintf(stderr, " isdst=%d", tmp->tm_isdst);
485 			(void) fprintf(stderr, " -> ");
486 			(void) fprintf(stderr, tformat(), t);
487 			(void) fprintf(stderr, "\n");
488 			errout = true;
489 		}
490 	}
491 	return tmp;
492 }
493 #endif /* !defined TYPECHECK */
494 
495 static void
496 abbrok(const char *const abbrp, const char *const zone)
497 {
498 	const char *cp;
499 	const char *wp;
500 
501 	if (warned)
502 		return;
503 	cp = abbrp;
504 	while (is_alpha(*cp) || is_digit(*cp) || *cp == '-' || *cp == '+')
505 		++cp;
506 	if (cp - abbrp < 3)
507 		wp = _("has fewer than 3 characters");
508 	else if (cp - abbrp > 6)
509 		wp = _("has more than 6 characters");
510 	else if (*cp)
511 		wp = _("has characters other than ASCII alphanumerics, '-' or '+'");
512 	else
513 		return;
514 	(void) fflush(stdout);
515 	(void) fprintf(stderr,
516 		_("%s: warning: zone \"%s\" abbreviation \"%s\" %s\n"),
517 		progname, zone, abbrp, wp);
518 	warned = errout = true;
519 }
520 
521 /* Return a time zone abbreviation.  If the abbreviation needs to be
522    saved, use *BUF (of size *BUFALLOC) to save it, and return the
523    abbreviation in the possibly-reallocated *BUF.  Otherwise, just
524    return the abbreviation.  Get the abbreviation from TMP.
525    Exit on memory allocation failure.  */
526 static char const *
527 saveabbr(char **buf, size_t *bufalloc, struct tm const *tmp)
528 {
529 	char const *ab = abbr(tmp);
530 	if (HAVE_LOCALTIME_RZ)
531 		return ab;
532 	else {
533 		size_t ablen = strlen(ab);
534 		if (*bufalloc <= ablen) {
535 			free(*buf);
536 
537 			/* Make the new buffer at least twice as long as the
538 			   old, to avoid O(N**2) behavior on repeated calls.  */
539 			*bufalloc = sumsize(*bufalloc, ablen + 1);
540 			*buf = malloc(*bufalloc);
541 			if (! *buf) {
542 				err(EXIT_FAILURE, "malloc");
543 			}
544 		}
545 		return strcpy(*buf, ab);
546 	}
547 }
548 
549 static void
550 close_file(FILE *stream)
551 {
552 	char const *e = (ferror(stream) ? _("I/O error")
553 	    : fclose(stream) != 0 ? strerror(errno) : NULL);
554 	if (e) {
555 		errx(EXIT_FAILURE, "%s", e);
556 	}
557 }
558 
559 __dead static void
560 usage(FILE *const stream, const int status)
561 {
562 	(void) fprintf(stream,
563 _("%s: usage: %s [--version] [--help] [-{vV}] [-{ct} [lo,]hi] zonename ...\n"
564   "\n"
565   "Report bugs to %s.\n"),
566 		       progname, progname, REPORT_BUGS_TO);
567 	if (status == EXIT_SUCCESS)
568 		close_file(stream);
569 	exit(status);
570 }
571 
572 int
573 main(int argc, char *argv[])
574 {
575 	/* These are static so that they're initially zero.  */
576 	static char *		abbrev;
577 	static size_t		abbrevsize;
578 	static struct tm	newtm;
579 
580 	int		i;
581 	bool		vflag;
582 	bool		Vflag;
583 	char *		cutarg;
584 	char *		cuttimes;
585 	time_t		cutlotime;
586 	time_t		cuthitime;
587 	time_t		now;
588 	time_t		t;
589 	time_t		newt;
590 	struct tm	tm;
591 	struct tm *	tmp;
592 	struct tm *	newtmp;
593 
594 	cutlotime = absolute_min_time;
595 	cuthitime = absolute_max_time;
596 #if HAVE_GETTEXT
597 	(void) setlocale(LC_ALL, "");
598 #ifdef TZ_DOMAINDIR
599 	(void) bindtextdomain(TZ_DOMAIN, TZ_DOMAINDIR);
600 #endif /* defined TEXTDOMAINDIR */
601 	(void) textdomain(TZ_DOMAIN);
602 #endif /* HAVE_GETTEXT */
603 	progname = argv[0];
604 	for (i = 1; i < argc; ++i)
605 		if (strcmp(argv[i], "--version") == 0) {
606 			(void) printf("zdump %s%s\n", PKGVERSION, TZVERSION);
607 			return EXIT_SUCCESS;
608 		} else if (strcmp(argv[i], "--help") == 0) {
609 			usage(stdout, EXIT_SUCCESS);
610 		}
611 	vflag = Vflag = false;
612 	cutarg = cuttimes = NULL;
613 	for (;;)
614 	  switch (getopt(argc, argv, "c:t:vV")) {
615 	  case 'c': cutarg = optarg; break;
616 	  case 't': cuttimes = optarg; break;
617 	  case 'v': vflag = true; break;
618 	  case 'V': Vflag = true; break;
619 	  case -1:
620 	    if (! (optind == argc - 1 && strcmp(argv[optind], "=") == 0))
621 	      goto arg_processing_done;
622 	    /* Fall through.  */
623 	  default:
624 	    usage(stderr, EXIT_FAILURE);
625 	  }
626  arg_processing_done:;
627 
628 	if (vflag | Vflag) {
629 		intmax_t	lo;
630 		intmax_t	hi;
631 		char *loend, *hiend;
632 		intmax_t cutloyear = ZDUMP_LO_YEAR;
633 		intmax_t cuthiyear = ZDUMP_HI_YEAR;
634 		if (cutarg != NULL) {
635 			lo = strtoimax(cutarg, &loend, 10);
636 			if (cutarg != loend && !*loend) {
637 				hi = lo;
638 				cuthiyear = hi;
639 			} else if (cutarg != loend && *loend == ','
640 				   && (hi = strtoimax(loend + 1, &hiend, 10),
641 				       loend + 1 != hiend && !*hiend)) {
642 				cutloyear = lo;
643 				cuthiyear = hi;
644 			} else {
645 				fprintf(stderr, _("%s: wild -c argument %s\n"),
646 					progname, cutarg);
647 				return EXIT_FAILURE;
648 			}
649 		}
650 		if (cutarg != NULL || cuttimes == NULL) {
651 			cutlotime = yeartot(cutloyear);
652 			cuthitime = yeartot(cuthiyear);
653 		}
654 		if (cuttimes != NULL) {
655 			lo = strtoimax(cuttimes, &loend, 10);
656 			if (cuttimes != loend && !*loend) {
657 				hi = lo;
658 				if (hi < cuthitime) {
659 					if (hi < absolute_min_time)
660 						hi = absolute_min_time;
661 					cuthitime = hi;
662 				}
663 			} else if (cuttimes != loend && *loend == ','
664 				   && (hi = strtoimax(loend + 1, &hiend, 10),
665 				       loend + 1 != hiend && !*hiend)) {
666 				if (cutlotime < lo) {
667 					if (absolute_max_time < lo)
668 						lo = absolute_max_time;
669 					cutlotime = lo;
670 				}
671 				if (hi < cuthitime) {
672 					if (hi < absolute_min_time)
673 						hi = absolute_min_time;
674 					cuthitime = hi;
675 				}
676 			} else {
677 				(void) fprintf(stderr,
678 					_("%s: wild -t argument %s\n"),
679 					progname, cuttimes);
680 				return EXIT_FAILURE;
681 			}
682 		}
683 	}
684 	gmtzinit();
685 	now = time(NULL);
686 	longest = 0;
687 	for (i = optind; i < argc; i++) {
688 		size_t arglen = strlen(argv[i]);
689 		if (longest < arglen)
690 			longest = arglen < INT_MAX ? arglen : INT_MAX;
691 	}
692 
693 	for (i = optind; i < argc; ++i) {
694 		timezone_t tz = tzalloc(argv[i]);
695 		char const *ab;
696 		if (!tz) {
697 			errx(EXIT_FAILURE, "%s", argv[i]);
698 		}
699 		if (! (vflag | Vflag)) {
700 			show(tz, argv[i], now, false);
701 			tzfree(tz);
702 			continue;
703 		}
704 		warned = false;
705 		t = absolute_min_time;
706 		if (!Vflag) {
707 			show(tz, argv[i], t, true);
708 			t += SECSPERDAY;
709 			show(tz, argv[i], t, true);
710 		}
711 		if (t < cutlotime)
712 			t = cutlotime;
713 		tmp = my_localtime_rz(tz, &t, &tm);
714 		if (tmp)
715 			ab = saveabbr(&abbrev, &abbrevsize, &tm);
716 		else
717 			ab = NULL;
718 		while (t < cuthitime) {
719 			newt = ((t < absolute_max_time - SECSPERDAY / 2
720 				&& t + SECSPERDAY / 2 < cuthitime)
721 				? t + SECSPERDAY / 2
722 				: cuthitime);
723 			newtmp = localtime_rz(tz, &newt, &newtm);
724 			if ((tmp == NULL || newtmp == NULL) ? (tmp != newtmp) :
725 			    (delta(&newtm, &tm) != (newt - t) ||
726 			    newtm.tm_isdst != tm.tm_isdst ||
727 			    strcmp(abbr(&newtm), ab) != 0)) {
728 				newt = hunt(tz, argv[i], t, newt);
729 				newtmp = localtime_rz(tz, &newt, &newtm);
730 				if (newtmp)
731 					  ab = saveabbr(&abbrev, &abbrevsize,
732 							&newtm);
733 			}
734 			t = newt;
735 			tm = newtm;
736 			tmp = newtmp;
737 		}
738 		if (!Vflag) {
739 			t = absolute_max_time;
740 			t -= SECSPERDAY;
741 			show(tz, argv[i], t, true);
742 			t += SECSPERDAY;
743 			show(tz, argv[i], t, true);
744 		}
745 		tzfree(tz);
746 	}
747 	close_file(stdout);
748 	if (errout && (ferror(stderr) || fclose(stderr) != 0))
749 		return EXIT_FAILURE;
750 	return EXIT_SUCCESS;
751 }
752 
753 static time_t
754 yeartot(intmax_t y)
755 {
756 	intmax_t	myy, seconds, years;
757 	time_t		t;
758 
759 	myy = EPOCH_YEAR;
760 	t = 0;
761 	while (myy < y) {
762 		if (SECSPER400YEARS_FITS && 400 <= y - myy) {
763 			intmax_t diff400 = (y - myy) / 400;
764 			if (INTMAX_MAX / SECSPER400YEARS < diff400)
765 				return absolute_max_time;
766 			seconds = diff400 * SECSPER400YEARS;
767 			years = diff400 * 400;
768                 } else {
769 			seconds = isleap(myy) ? SECSPERLYEAR : SECSPERNYEAR;
770 			years = 1;
771 		}
772 		myy += years;
773 		if (t > absolute_max_time - seconds)
774 			return absolute_max_time;
775 		t += seconds;
776 	}
777 	while (y < myy) {
778 		if (SECSPER400YEARS_FITS && y + 400 <= myy && myy < 0) {
779 			intmax_t diff400 = (myy - y) / 400;
780 			if (INTMAX_MAX / SECSPER400YEARS < diff400)
781 				return absolute_min_time;
782 			seconds = diff400 * SECSPER400YEARS;
783 			years = diff400 * 400;
784 		} else {
785 			seconds = isleap(myy - 1) ? SECSPERLYEAR : SECSPERNYEAR;
786 			years = 1;
787 		}
788 		myy -= years;
789 		if (t < absolute_min_time + seconds)
790 			return absolute_min_time;
791 		t -= seconds;
792 	}
793 	return t;
794 }
795 
796 static time_t
797 hunt(timezone_t tz, char *name, time_t lot, time_t hit)
798 {
799 	static char *		loab;
800 	static size_t		loabsize;
801 	char const *		ab;
802 	time_t			t;
803 	struct tm		lotm;
804 	struct tm *	lotmp;
805 	struct tm		tm;
806 	struct tm *	tmp;
807 
808 	lotmp = my_localtime_rz(tz, &lot, &lotm);
809 	if (lotmp)
810 		ab = saveabbr(&loab, &loabsize, &lotm);
811 	else
812 		ab = NULL;
813 	for ( ; ; ) {
814 		time_t diff = hit - lot;
815 		if (diff < 2)
816 			break;
817 		t = lot;
818 		t += diff / 2;
819 		if (t <= lot)
820 			++t;
821 		else if (t >= hit)
822 			--t;
823 		tmp = my_localtime_rz(tz, &t, &tm);
824 		if ((lotmp == NULL || tmp == NULL) ? (lotmp == tmp) :
825 			(delta(&tm, &lotm) == (t - lot) &&
826 			tm.tm_isdst == lotm.tm_isdst &&
827 			strcmp(abbr(&tm), ab) == 0)) {
828 				lot = t;
829 				lotm = tm;
830 				lotmp = tmp;
831 		} else	hit = t;
832 	}
833 	show(tz, name, lot, true);
834 	show(tz, name, hit, true);
835 	return hit;
836 }
837 
838 /*
839 ** Thanks to Paul Eggert for logic used in delta.
840 */
841 
842 static intmax_t
843 delta(struct tm *newp, struct tm *oldp)
844 {
845 	intmax_t	result;
846 	int		tmy;
847 
848 	if (newp->tm_year < oldp->tm_year)
849 		return -delta(oldp, newp);
850 	result = 0;
851 	for (tmy = oldp->tm_year; tmy < newp->tm_year; ++tmy)
852 		result += DAYSPERNYEAR + isleap_sum(tmy, TM_YEAR_BASE);
853 	result += newp->tm_yday - oldp->tm_yday;
854 	result *= HOURSPERDAY;
855 	result += newp->tm_hour - oldp->tm_hour;
856 	result *= MINSPERHOUR;
857 	result += newp->tm_min - oldp->tm_min;
858 	result *= SECSPERMIN;
859 	result += newp->tm_sec - oldp->tm_sec;
860 	return result;
861 }
862 
863 #ifndef TM_GMTOFF
864 /* Return A->tm_yday, adjusted to compare it fairly to B->tm_yday.
865    Assume A and B differ by at most one year.  */
866 static int
867 adjusted_yday(struct tm const *a, struct tm const *b)
868 {
869 	int yday = a->tm_yday;
870 	if (b->tm_year < a->tm_year)
871 		yday += 365 + isleap_sum(b->tm_year, TM_YEAR_BASE);
872 	return yday;
873 }
874 #endif
875 
876 /* If A is the broken-down local time and B the broken-down UTC for
877    the same instant, return A's UTC offset in seconds, where positive
878    offsets are east of Greenwich.  On failure, return LONG_MIN.  */
879 static long
880 gmtoff(struct tm const *a, struct tm const *b)
881 {
882 #ifdef TM_GMTOFF
883 	return a->TM_GMTOFF;
884 #else
885 	if (! b)
886 		return LONG_MIN;
887 	else {
888 		int ayday = adjusted_yday(a, b);
889 		int byday = adjusted_yday(b, a);
890 		int days = ayday - byday;
891 		long hours = a->tm_hour - b->tm_hour + 24 * days;
892 		long minutes = a->tm_min - b->tm_min + 60 * hours;
893 		long seconds = a->tm_sec - b->tm_sec + 60 * minutes;
894 		return seconds;
895 	}
896 #endif
897 }
898 
899 static void
900 show(timezone_t tz, char *zone, time_t t, bool v)
901 {
902 	struct tm *	tmp;
903 	struct tm *	gmtmp;
904 	struct tm tm, gmtm;
905 
906 	(void) printf("%-*s  ", (int) longest, zone);
907 	if (v) {
908 		gmtmp = my_gmtime_r(&t, &gmtm);
909 		if (gmtmp == NULL) {
910 			printf(tformat(), t);
911 		} else {
912 			dumptime(gmtmp);
913 			(void) printf(" UT");
914 		}
915 		(void) printf(" = ");
916 	}
917 	tmp = my_localtime_rz(tz, &t, &tm);
918 	dumptime(tmp);
919 	if (tmp != NULL) {
920 		if (*abbr(tmp) != '\0')
921 			(void) printf(" %s", abbr(tmp));
922 		if (v) {
923 			long off = gmtoff(tmp, gmtmp);
924 			(void) printf(" isdst=%d", tmp->tm_isdst);
925 			if (off != LONG_MIN)
926 				(void) printf(" gmtoff=%ld", off);
927 		}
928 	}
929 	(void) printf("\n");
930 	if (tmp != NULL && *abbr(tmp) != '\0')
931 		abbrok(abbr(tmp), zone);
932 }
933 
934 static const char *
935 abbr(struct tm const *tmp)
936 {
937 #ifdef TM_ZONE
938 	return tmp->TM_ZONE;
939 #else
940 	return (0 <= tmp->tm_isdst && tzname[0 < tmp->tm_isdst]
941 		? tzname[0 < tmp->tm_isdst]
942 		: "");
943 #endif
944 }
945 
946 /*
947 ** The code below can fail on certain theoretical systems;
948 ** it works on all known real-world systems as of 2004-12-30.
949 */
950 
951 static const char *
952 tformat(void)
953 {
954 	if (0 > (time_t) -1) {		/* signed */
955 		if (sizeof (time_t) == sizeof (intmax_t))
956 			return "%"PRIdMAX;
957 		if (sizeof (time_t) > sizeof (long))
958 			return "%lld";
959 		if (sizeof (time_t) > sizeof (int))
960 			return "%ld";
961 		return "%d";
962 	}
963 #ifdef PRIuMAX
964 	if (sizeof (time_t) == sizeof (uintmax_t))
965 		return "%"PRIuMAX;
966 #endif
967 	if (sizeof (time_t) > sizeof (unsigned long))
968 		return "%llu";
969 	if (sizeof (time_t) > sizeof (unsigned int))
970 		return "%lu";
971 	return "%u";
972 }
973 
974 static void
975 dumptime(const struct tm *timeptr)
976 {
977 	static const char	wday_name[][3] = {
978 		"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
979 	};
980 	static const char	mon_name[][3] = {
981 		"Jan", "Feb", "Mar", "Apr", "May", "Jun",
982 		"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
983 	};
984 	const char *	wn;
985 	const char *	mn;
986 	int		lead;
987 	int		trail;
988 
989 	if (timeptr == NULL) {
990 		printf("NULL");
991 		return;
992 	}
993 	/*
994 	** The packaged localtime_rz and gmtime_r never put out-of-range
995 	** values in tm_wday or tm_mon, but since this code might be compiled
996 	** with other (perhaps experimental) versions, paranoia is in order.
997 	*/
998 	if (timeptr->tm_wday < 0 || timeptr->tm_wday >=
999 		(int) (sizeof wday_name / sizeof wday_name[0]))
1000 			wn = "???";
1001 	else		wn = wday_name[timeptr->tm_wday];
1002 	if (timeptr->tm_mon < 0 || timeptr->tm_mon >=
1003 		(int) (sizeof mon_name / sizeof mon_name[0]))
1004 			mn = "???";
1005 	else		mn = mon_name[timeptr->tm_mon];
1006 	printf("%.3s %.3s%3d %.2d:%.2d:%.2d ",
1007 		wn, mn,
1008 		timeptr->tm_mday, timeptr->tm_hour,
1009 		timeptr->tm_min, timeptr->tm_sec);
1010 #define DIVISOR	10
1011 	trail = timeptr->tm_year % DIVISOR + TM_YEAR_BASE % DIVISOR;
1012 	lead = timeptr->tm_year / DIVISOR + TM_YEAR_BASE / DIVISOR +
1013 		trail / DIVISOR;
1014 	trail %= DIVISOR;
1015 	if (trail < 0 && lead > 0) {
1016 		trail += DIVISOR;
1017 		--lead;
1018 	} else if (lead < 0 && trail > 0) {
1019 		trail -= DIVISOR;
1020 		++lead;
1021 	}
1022 	if (lead == 0)
1023 		printf("%d", trail);
1024 	else	printf("%d%d", lead, ((trail < 0) ? -trail : trail));
1025 }
1026