xref: /minix3/lib/libc/time/localtime.c (revision cdfb5ab81f82cdcb0f58d139385d626df29f4069)
1 /*	$NetBSD: localtime.c,v 1.54 2011/01/15 15:42:10 christos Exp $	*/
2 
3 /*
4 ** This file is in the public domain, so clarified as of
5 ** 1996-06-05 by Arthur David Olson.
6 */
7 
8 #include <sys/cdefs.h>
9 #if defined(LIBC_SCCS) && !defined(lint)
10 #if 0
11 static char	elsieid[] = "@(#)localtime.c	8.9";
12 #else
13 __RCSID("$NetBSD: localtime.c,v 1.54 2011/01/15 15:42:10 christos Exp $");
14 #endif
15 #endif /* LIBC_SCCS and not lint */
16 
17 /*
18 ** Leap second handling from Bradley White.
19 ** POSIX-style TZ environment variable handling from Guy Harris.
20 */
21 
22 /*LINTLIBRARY*/
23 
24 #include "namespace.h"
25 #include "private.h"
26 #include "tzfile.h"
27 #include "fcntl.h"
28 #include "reentrant.h"
29 
30 #if defined(__weak_alias)
31 __weak_alias(ctime_r,__ctime_r50)
32 __weak_alias(ctime_rz,__ctime_rz50)
33 __weak_alias(daylight,_daylight)
34 __weak_alias(mktime_z,__mktime_z50)
35 __weak_alias(localtime_r,__localtime_r50)
36 __weak_alias(localtime_rz,__localtime_rz50)
37 __weak_alias(posix2time,__posix2time50)
38 __weak_alias(posix2time_z,__posix2time_z50)
39 __weak_alias(tzname,_tzname)
40 #endif
41 
42 #include "float.h"	/* for FLT_MAX and DBL_MAX */
43 
44 #ifndef TZ_ABBR_MAX_LEN
45 #define TZ_ABBR_MAX_LEN	16
46 #endif /* !defined TZ_ABBR_MAX_LEN */
47 
48 #ifndef TZ_ABBR_CHAR_SET
49 #define TZ_ABBR_CHAR_SET \
50 	"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789 :+-._"
51 #endif /* !defined TZ_ABBR_CHAR_SET */
52 
53 #ifndef TZ_ABBR_ERR_CHAR
54 #define TZ_ABBR_ERR_CHAR	'_'
55 #endif /* !defined TZ_ABBR_ERR_CHAR */
56 
57 /*
58 ** SunOS 4.1.1 headers lack O_BINARY.
59 */
60 
61 #ifdef O_BINARY
62 #define OPEN_MODE	(O_RDONLY | O_BINARY)
63 #endif /* defined O_BINARY */
64 #ifndef O_BINARY
65 #define OPEN_MODE	O_RDONLY
66 #endif /* !defined O_BINARY */
67 
68 #ifndef WILDABBR
69 /*
70 ** Someone might make incorrect use of a time zone abbreviation:
71 **	1.	They might reference tzname[0] before calling tzset (explicitly
72 **		or implicitly).
73 **	2.	They might reference tzname[1] before calling tzset (explicitly
74 **		or implicitly).
75 **	3.	They might reference tzname[1] after setting to a time zone
76 **		in which Daylight Saving Time is never observed.
77 **	4.	They might reference tzname[0] after setting to a time zone
78 **		in which Standard Time is never observed.
79 **	5.	They might reference tm.TM_ZONE after calling offtime.
80 ** What's best to do in the above cases is open to debate;
81 ** for now, we just set things up so that in any of the five cases
82 ** WILDABBR is used. Another possibility: initialize tzname[0] to the
83 ** string "tzname[0] used before set", and similarly for the other cases.
84 ** And another: initialize tzname[0] to "ERA", with an explanation in the
85 ** manual page of what this "time zone abbreviation" means (doing this so
86 ** that tzname[0] has the "normal" length of three characters).
87 */
88 #define WILDABBR	"   "
89 #endif /* !defined WILDABBR */
90 
91 static const char	wildabbr[] = WILDABBR;
92 
93 static char		gmt[] = "GMT";
94 
95 /*
96 ** The DST rules to use if TZ has no rules and we can't load TZDEFRULES.
97 ** We default to US rules as of 1999-08-17.
98 ** POSIX 1003.1 section 8.1.1 says that the default DST rules are
99 ** implementation dependent; for historical reasons, US rules are a
100 ** common default.
101 */
102 #ifndef TZDEFRULESTRING
103 #define TZDEFRULESTRING ",M4.1.0,M10.5.0"
104 #endif /* !defined TZDEFDST */
105 
106 struct ttinfo {				/* time type information */
107 	long		tt_gmtoff;	/* UTC offset in seconds */
108 	int		tt_isdst;	/* used to set tm_isdst */
109 	int		tt_abbrind;	/* abbreviation list index */
110 	int		tt_ttisstd;	/* TRUE if transition is std time */
111 	int		tt_ttisgmt;	/* TRUE if transition is UTC */
112 };
113 
114 struct lsinfo {				/* leap second information */
115 	time_t		ls_trans;	/* transition time */
116 	long		ls_corr;	/* correction to apply */
117 };
118 
119 #define BIGGEST(a, b)	(((a) > (b)) ? (a) : (b))
120 
121 #ifdef TZNAME_MAX
122 #define MY_TZNAME_MAX	TZNAME_MAX
123 #endif /* defined TZNAME_MAX */
124 #ifndef TZNAME_MAX
125 #define MY_TZNAME_MAX	255
126 #endif /* !defined TZNAME_MAX */
127 
128 struct __state {
129 	int		leapcnt;
130 	int		timecnt;
131 	int		typecnt;
132 	int		charcnt;
133 	int		goback;
134 	int		goahead;
135 	time_t		ats[TZ_MAX_TIMES];
136 	unsigned char	types[TZ_MAX_TIMES];
137 	struct ttinfo	ttis[TZ_MAX_TYPES];
138 	char		chars[/*CONSTCOND*/BIGGEST(BIGGEST(TZ_MAX_CHARS + 1, sizeof gmt),
139 				(2 * (MY_TZNAME_MAX + 1)))];
140 	struct lsinfo	lsis[TZ_MAX_LEAPS];
141 };
142 
143 struct rule {
144 	int		r_type;		/* type of rule--see below */
145 	int		r_day;		/* day number of rule */
146 	int		r_week;		/* week number of rule */
147 	int		r_mon;		/* month number of rule */
148 	long		r_time;		/* transition time of rule */
149 };
150 
151 #define JULIAN_DAY		0	/* Jn - Julian day */
152 #define DAY_OF_YEAR		1	/* n - day of year */
153 #define MONTH_NTH_DAY_OF_WEEK	2	/* Mm.n.d - month, week, day of week */
154 
155 typedef struct tm *(*subfun_t)(const timezone_t sp, const time_t *timep,
156 			       long offset, struct tm *tmp);
157 
158 /*
159 ** Prototypes for static functions.
160 */
161 
162 static long		detzcode(const char * codep);
163 static time_t		detzcode64(const char * codep);
164 static int		differ_by_repeat(time_t t1, time_t t0);
165 static const char *	getzname(const char * strp);
166 static const char *	getqzname(const char * strp, const int delim);
167 static const char *	getnum(const char * strp, int * nump, int min,
168 				int max);
169 static const char *	getsecs(const char * strp, long * secsp);
170 static const char *	getoffset(const char * strp, long * offsetp);
171 static const char *	getrule(const char * strp, struct rule * rulep);
172 static void		gmtload(timezone_t sp);
173 static struct tm *	gmtsub(const timezone_t sp, const time_t *timep,
174 				long offset, struct tm * tmp);
175 static struct tm *	localsub(const timezone_t sp, const time_t *timep,
176 				long offset, struct tm *tmp);
177 static int		increment_overflow(int * number, int delta);
178 static int		leaps_thru_end_of(int y);
179 static int		long_increment_overflow(long * number, int delta);
180 static int		long_normalize_overflow(long * tensptr,
181 				int * unitsptr, int base);
182 static int		normalize_overflow(int * tensptr, int * unitsptr,
183 				int base);
184 static void		settzname(void);
185 static time_t		time1(const timezone_t sp, struct tm * const tmp,
186 				subfun_t funcp, long offset);
187 static time_t		time2(const timezone_t sp, struct tm * const tmp,
188 				subfun_t funcp,
189 				const long offset, int *const okayp);
190 static time_t		time2sub(const timezone_t sp, struct tm * consttmp,
191 				subfun_t funcp, const long offset,
192 				int *const okayp, const int do_norm_secs);
193 static struct tm *	timesub(const timezone_t sp, const time_t * timep,
194 				long offset, struct tm * tmp);
195 static int		tmcomp(const struct tm * atmp,
196 				const struct tm * btmp);
197 static time_t		transtime(time_t janfirst, int year,
198 				const struct rule * rulep, long offset);
199 static int		typesequiv(const timezone_t sp, int a, int b);
200 static int		tzload(timezone_t sp, const char * name,
201 				int doextend);
202 static int		tzparse(timezone_t sp, const char * name,
203 				int lastditch);
204 static void		tzset_unlocked(void);
205 static void		tzsetwall_unlocked(void);
206 static long		leapcorr(const timezone_t sp, time_t * timep);
207 
208 static timezone_t lclptr;
209 static timezone_t gmtptr;
210 
211 #ifndef TZ_STRLEN_MAX
212 #define TZ_STRLEN_MAX 255
213 #endif /* !defined TZ_STRLEN_MAX */
214 
215 static char		lcl_TZname[TZ_STRLEN_MAX + 1];
216 static int		lcl_is_set;
217 static int		gmt_is_set;
218 
219 #if !defined(__LIBC12_SOURCE__)
220 
221 __aconst char *		tzname[2] = {
222 	(__aconst char *)__UNCONST(wildabbr),
223 	(__aconst char *)__UNCONST(wildabbr)
224 };
225 
226 #else
227 
228 extern __aconst char *	tzname[2];
229 
230 #endif
231 
232 #ifdef _REENTRANT
233 static rwlock_t lcl_lock = RWLOCK_INITIALIZER;
234 #endif
235 
236 /*
237 ** Section 4.12.3 of X3.159-1989 requires that
238 **	Except for the strftime function, these functions [asctime,
239 **	ctime, gmtime, localtime] return values in one of two static
240 **	objects: a broken-down time structure and an array of char.
241 ** Thanks to Paul Eggert for noting this.
242 */
243 
244 static struct tm	tm;
245 
246 #ifdef USG_COMPAT
247 #if !defined(__LIBC12_SOURCE__)
248 long 			timezone = 0;
249 int			daylight = 0;
250 #else
251 extern int		daylight;
252 extern long		timezone __RENAME(__timezone13);
253 #endif
254 #endif /* defined USG_COMPAT */
255 
256 #ifdef ALTZONE
257 time_t			altzone = 0;
258 #endif /* defined ALTZONE */
259 
260 static long
261 detzcode(const char *const codep)
262 {
263 	long	result;
264 	int	i;
265 
266 	result = (codep[0] & 0x80) ? ~0L : 0;
267 	for (i = 0; i < 4; ++i)
268 		result = (result << 8) | (codep[i] & 0xff);
269 	return result;
270 }
271 
272 static time_t
273 detzcode64(const char *const codep)
274 {
275 	time_t	result;
276 	int	i;
277 
278 	result = (codep[0] & 0x80) ? -1 : 0;
279 	for (i = 0; i < 8; ++i)
280 		result = result * 256 + (codep[i] & 0xff);
281 	return result;
282 }
283 
284 const char *
285 tzgetname(const timezone_t sp, int isdst)
286 {
287 	int i;
288 	for (i = 0; i < sp->timecnt; ++i) {
289 		const struct ttinfo *const ttisp = &sp->ttis[sp->types[i]];
290 
291 		if (ttisp->tt_isdst == isdst)
292 			return &sp->chars[ttisp->tt_abbrind];
293 	}
294 	return NULL;
295 }
296 
297 static void
298 settzname_z(timezone_t sp)
299 {
300 	int			i;
301 
302 	/*
303 	** Scrub the abbreviations.
304 	** First, replace bogus characters.
305 	*/
306 	for (i = 0; i < sp->charcnt; ++i)
307 		if (strchr(TZ_ABBR_CHAR_SET, sp->chars[i]) == NULL)
308 			sp->chars[i] = TZ_ABBR_ERR_CHAR;
309 	/*
310 	** Second, truncate long abbreviations.
311 	*/
312 	for (i = 0; i < sp->typecnt; ++i) {
313 		const struct ttinfo * const	ttisp = &sp->ttis[i];
314 		char *				cp = &sp->chars[ttisp->tt_abbrind];
315 
316 		if (strlen(cp) > TZ_ABBR_MAX_LEN &&
317 			strcmp(cp, GRANDPARENTED) != 0)
318 				*(cp + TZ_ABBR_MAX_LEN) = '\0';
319 	}
320 }
321 
322 static void
323 settzname(void)
324 {
325 	timezone_t const	sp = lclptr;
326 	int			i;
327 
328 	tzname[0] = (__aconst char *)__UNCONST(wildabbr);
329 	tzname[1] = (__aconst char *)__UNCONST(wildabbr);
330 #ifdef USG_COMPAT
331 	daylight = 0;
332 	timezone = 0;
333 #endif /* defined USG_COMPAT */
334 #ifdef ALTZONE
335 	altzone = 0;
336 #endif /* defined ALTZONE */
337 	if (sp == NULL) {
338 		tzname[0] = tzname[1] = (__aconst char *)__UNCONST(gmt);
339 		return;
340 	}
341 	for (i = 0; i < sp->typecnt; ++i) {
342 		const struct ttinfo * const	ttisp = &sp->ttis[i];
343 
344 		tzname[ttisp->tt_isdst] =
345 			&sp->chars[ttisp->tt_abbrind];
346 #ifdef USG_COMPAT
347 		if (ttisp->tt_isdst)
348 			daylight = 1;
349 		if (i == 0 || !ttisp->tt_isdst)
350 			timezone = -(ttisp->tt_gmtoff);
351 #endif /* defined USG_COMPAT */
352 #ifdef ALTZONE
353 		if (i == 0 || ttisp->tt_isdst)
354 			altzone = -(ttisp->tt_gmtoff);
355 #endif /* defined ALTZONE */
356 	}
357 	/*
358 	** And to get the latest zone names into tzname. . .
359 	*/
360 	for (i = 0; i < sp->timecnt; ++i) {
361 		register const struct ttinfo * const	ttisp =
362 							&sp->ttis[
363 								sp->types[i]];
364 
365 		tzname[ttisp->tt_isdst] =
366 			&sp->chars[ttisp->tt_abbrind];
367 	}
368 	settzname_z(sp);
369 }
370 
371 static int
372 differ_by_repeat(const time_t t1, const time_t t0)
373 {
374 /* CONSTCOND */
375 	if (TYPE_INTEGRAL(time_t) &&
376 		TYPE_BIT(time_t) - TYPE_SIGNED(time_t) < SECSPERREPEAT_BITS)
377 			return 0;
378 	return (int_fast64_t)t1 - (int_fast64_t)t0 == SECSPERREPEAT;
379 }
380 
381 static int
382 tzload(timezone_t sp, const char *name, const int doextend)
383 {
384 	const char *		p;
385 	int			i;
386 	int			fid;
387 	int			stored;
388 	int			nread;
389 	union {
390 		struct tzhead	tzhead;
391 		char		buf[2 * sizeof(struct tzhead) +
392 					2 * sizeof *sp +
393 					4 * TZ_MAX_TIMES];
394 	} u;
395 
396 	sp->goback = sp->goahead = FALSE;
397 	if (name == NULL && (name = TZDEFAULT) == NULL)
398 		return -1;
399 	{
400 		int	doaccess;
401 		/*
402 		** Section 4.9.1 of the C standard says that
403 		** "FILENAME_MAX expands to an integral constant expression
404 		** that is the size needed for an array of char large enough
405 		** to hold the longest file name string that the implementation
406 		** guarantees can be opened."
407 		*/
408 		char		fullname[FILENAME_MAX + 1];
409 
410 		if (name[0] == ':')
411 			++name;
412 		doaccess = name[0] == '/';
413 		if (!doaccess) {
414 			if ((p = TZDIR) == NULL)
415 				return -1;
416 			if ((strlen(p) + strlen(name) + 1) >= sizeof fullname)
417 				return -1;
418 			(void) strcpy(fullname, p);	/* XXX strcpy is safe */
419 			(void) strcat(fullname, "/");	/* XXX strcat is safe */
420 			(void) strcat(fullname, name);	/* XXX strcat is safe */
421 			/*
422 			** Set doaccess if '.' (as in "../") shows up in name.
423 			*/
424 			if (strchr(name, '.') != NULL)
425 				doaccess = TRUE;
426 			name = fullname;
427 		}
428 		if (doaccess && access(name, R_OK) != 0)
429 			return -1;
430 		/*
431 		 * XXX potential security problem here if user of a set-id
432 		 * program has set TZ (which is passed in as name) here,
433 		 * and uses a race condition trick to defeat the access(2)
434 		 * above.
435 		 */
436 		if ((fid = open(name, OPEN_MODE)) == -1)
437 			return -1;
438 	}
439 	nread = read(fid, u.buf, sizeof u.buf);
440 	if (close(fid) < 0 || nread <= 0)
441 		return -1;
442 	for (stored = 4; stored <= 8; stored *= 2) {
443 		int		ttisstdcnt;
444 		int		ttisgmtcnt;
445 
446 		ttisstdcnt = (int) detzcode(u.tzhead.tzh_ttisstdcnt);
447 		ttisgmtcnt = (int) detzcode(u.tzhead.tzh_ttisgmtcnt);
448 		sp->leapcnt = (int) detzcode(u.tzhead.tzh_leapcnt);
449 		sp->timecnt = (int) detzcode(u.tzhead.tzh_timecnt);
450 		sp->typecnt = (int) detzcode(u.tzhead.tzh_typecnt);
451 		sp->charcnt = (int) detzcode(u.tzhead.tzh_charcnt);
452 		p = u.tzhead.tzh_charcnt + sizeof u.tzhead.tzh_charcnt;
453 		if (sp->leapcnt < 0 || sp->leapcnt > TZ_MAX_LEAPS ||
454 			sp->typecnt <= 0 || sp->typecnt > TZ_MAX_TYPES ||
455 			sp->timecnt < 0 || sp->timecnt > TZ_MAX_TIMES ||
456 			sp->charcnt < 0 || sp->charcnt > TZ_MAX_CHARS ||
457 			(ttisstdcnt != sp->typecnt && ttisstdcnt != 0) ||
458 			(ttisgmtcnt != sp->typecnt && ttisgmtcnt != 0))
459 				return -1;
460 		if (nread - (p - u.buf) <
461 			sp->timecnt * stored +		/* ats */
462 			sp->timecnt +			/* types */
463 			sp->typecnt * 6 +		/* ttinfos */
464 			sp->charcnt +			/* chars */
465 			sp->leapcnt * (stored + 4) +	/* lsinfos */
466 			ttisstdcnt +			/* ttisstds */
467 			ttisgmtcnt)			/* ttisgmts */
468 				return -1;
469 		for (i = 0; i < sp->timecnt; ++i) {
470 			sp->ats[i] = (stored == 4) ?
471 				detzcode(p) : detzcode64(p);
472 			p += stored;
473 		}
474 		for (i = 0; i < sp->timecnt; ++i) {
475 			sp->types[i] = (unsigned char) *p++;
476 			if (sp->types[i] >= sp->typecnt)
477 				return -1;
478 		}
479 		for (i = 0; i < sp->typecnt; ++i) {
480 			struct ttinfo *	ttisp;
481 
482 			ttisp = &sp->ttis[i];
483 			ttisp->tt_gmtoff = detzcode(p);
484 			p += 4;
485 			ttisp->tt_isdst = (unsigned char) *p++;
486 			if (ttisp->tt_isdst != 0 && ttisp->tt_isdst != 1)
487 				return -1;
488 			ttisp->tt_abbrind = (unsigned char) *p++;
489 			if (ttisp->tt_abbrind < 0 ||
490 				ttisp->tt_abbrind > sp->charcnt)
491 					return -1;
492 		}
493 		for (i = 0; i < sp->charcnt; ++i)
494 			sp->chars[i] = *p++;
495 		sp->chars[i] = '\0';	/* ensure '\0' at end */
496 		for (i = 0; i < sp->leapcnt; ++i) {
497 			struct lsinfo *	lsisp;
498 
499 			lsisp = &sp->lsis[i];
500 			lsisp->ls_trans = (stored == 4) ?
501 				detzcode(p) : detzcode64(p);
502 			p += stored;
503 			lsisp->ls_corr = detzcode(p);
504 			p += 4;
505 		}
506 		for (i = 0; i < sp->typecnt; ++i) {
507 			struct ttinfo *	ttisp;
508 
509 			ttisp = &sp->ttis[i];
510 			if (ttisstdcnt == 0)
511 				ttisp->tt_ttisstd = FALSE;
512 			else {
513 				ttisp->tt_ttisstd = *p++;
514 				if (ttisp->tt_ttisstd != TRUE &&
515 					ttisp->tt_ttisstd != FALSE)
516 						return -1;
517 			}
518 		}
519 		for (i = 0; i < sp->typecnt; ++i) {
520 			struct ttinfo *	ttisp;
521 
522 			ttisp = &sp->ttis[i];
523 			if (ttisgmtcnt == 0)
524 				ttisp->tt_ttisgmt = FALSE;
525 			else {
526 				ttisp->tt_ttisgmt = *p++;
527 				if (ttisp->tt_ttisgmt != TRUE &&
528 					ttisp->tt_ttisgmt != FALSE)
529 						return -1;
530 			}
531 		}
532 		/*
533 		** Out-of-sort ats should mean we're running on a
534 		** signed time_t system but using a data file with
535 		** unsigned values (or vice versa).
536 		*/
537 		for (i = 0; i < sp->timecnt - 2; ++i)
538 			if (sp->ats[i] > sp->ats[i + 1]) {
539 				++i;
540 /* CONSTCOND */
541 				if (TYPE_SIGNED(time_t)) {
542 					/*
543 					** Ignore the end (easy).
544 					*/
545 					sp->timecnt = i;
546 				} else {
547 					/*
548 					** Ignore the beginning (harder).
549 					*/
550 					int	j;
551 
552 					for (j = 0; j + i < sp->timecnt; ++j) {
553 						sp->ats[j] = sp->ats[j + i];
554 						sp->types[j] = sp->types[j + i];
555 					}
556 					sp->timecnt = j;
557 				}
558 				break;
559 			}
560 		/*
561 		** If this is an old file, we're done.
562 		*/
563 		if (u.tzhead.tzh_version[0] == '\0')
564 			break;
565 		nread -= p - u.buf;
566 		for (i = 0; i < nread; ++i)
567 			u.buf[i] = p[i];
568 		/*
569 		** If this is a narrow integer time_t system, we're done.
570 		*/
571 		if (stored >= (int) sizeof(time_t)
572 /* CONSTCOND */
573 				&& TYPE_INTEGRAL(time_t))
574 			break;
575 	}
576 	if (doextend && nread > 2 &&
577 		u.buf[0] == '\n' && u.buf[nread - 1] == '\n' &&
578 		sp->typecnt + 2 <= TZ_MAX_TYPES) {
579 			struct __state ts;
580 			int	result;
581 
582 			u.buf[nread - 1] = '\0';
583 			result = tzparse(&ts, &u.buf[1], FALSE);
584 			if (result == 0 && ts.typecnt == 2 &&
585 				sp->charcnt + ts.charcnt <= TZ_MAX_CHARS) {
586 					for (i = 0; i < 2; ++i)
587 						ts.ttis[i].tt_abbrind +=
588 							sp->charcnt;
589 					for (i = 0; i < ts.charcnt; ++i)
590 						sp->chars[sp->charcnt++] =
591 							ts.chars[i];
592 					i = 0;
593 					while (i < ts.timecnt &&
594 						ts.ats[i] <=
595 						sp->ats[sp->timecnt - 1])
596 							++i;
597 					while (i < ts.timecnt &&
598 					    sp->timecnt < TZ_MAX_TIMES) {
599 						sp->ats[sp->timecnt] =
600 							ts.ats[i];
601 						sp->types[sp->timecnt] =
602 							sp->typecnt +
603 							ts.types[i];
604 						++sp->timecnt;
605 						++i;
606 					}
607 					sp->ttis[sp->typecnt++] = ts.ttis[0];
608 					sp->ttis[sp->typecnt++] = ts.ttis[1];
609 			}
610 	}
611 	if (sp->timecnt > 1) {
612 		for (i = 1; i < sp->timecnt; ++i)
613 			if (typesequiv(sp, sp->types[i], sp->types[0]) &&
614 				differ_by_repeat(sp->ats[i], sp->ats[0])) {
615 					sp->goback = TRUE;
616 					break;
617 				}
618 		for (i = sp->timecnt - 2; i >= 0; --i)
619 			if (typesequiv(sp, sp->types[sp->timecnt - 1],
620 				sp->types[i]) &&
621 				differ_by_repeat(sp->ats[sp->timecnt - 1],
622 				sp->ats[i])) {
623 					sp->goahead = TRUE;
624 					break;
625 		}
626 	}
627 	return 0;
628 }
629 
630 static int
631 typesequiv(const timezone_t sp, const int a, const int b)
632 {
633 	int	result;
634 
635 	if (sp == NULL ||
636 		a < 0 || a >= sp->typecnt ||
637 		b < 0 || b >= sp->typecnt)
638 			result = FALSE;
639 	else {
640 		const struct ttinfo *	ap = &sp->ttis[a];
641 		const struct ttinfo *	bp = &sp->ttis[b];
642 		result = ap->tt_gmtoff == bp->tt_gmtoff &&
643 			ap->tt_isdst == bp->tt_isdst &&
644 			ap->tt_ttisstd == bp->tt_ttisstd &&
645 			ap->tt_ttisgmt == bp->tt_ttisgmt &&
646 			strcmp(&sp->chars[ap->tt_abbrind],
647 			&sp->chars[bp->tt_abbrind]) == 0;
648 	}
649 	return result;
650 }
651 
652 static const int	mon_lengths[2][MONSPERYEAR] = {
653 	{ 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 },
654 	{ 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }
655 };
656 
657 static const int	year_lengths[2] = {
658 	DAYSPERNYEAR, DAYSPERLYEAR
659 };
660 
661 /*
662 ** Given a pointer into a time zone string, scan until a character that is not
663 ** a valid character in a zone name is found. Return a pointer to that
664 ** character.
665 */
666 
667 static const char *
668 getzname(strp)
669 const char *	strp;
670 {
671 	char	c;
672 
673 	while ((c = *strp) != '\0' && !is_digit(c) && c != ',' && c != '-' &&
674 		c != '+')
675 			++strp;
676 	return strp;
677 }
678 
679 /*
680 ** Given a pointer into an extended time zone string, scan until the ending
681 ** delimiter of the zone name is located. Return a pointer to the delimiter.
682 **
683 ** As with getzname above, the legal character set is actually quite
684 ** restricted, with other characters producing undefined results.
685 ** We don't do any checking here; checking is done later in common-case code.
686 */
687 
688 static const char *
689 getqzname(const char *strp, const int delim)
690 {
691 	int	c;
692 
693 	while ((c = *strp) != '\0' && c != delim)
694 		++strp;
695 	return strp;
696 }
697 
698 /*
699 ** Given a pointer into a time zone string, extract a number from that string.
700 ** Check that the number is within a specified range; if it is not, return
701 ** NULL.
702 ** Otherwise, return a pointer to the first character not part of the number.
703 */
704 
705 static const char *
706 getnum(strp, nump, min, max)
707 const char *	strp;
708 int * const		nump;
709 const int		min;
710 const int		max;
711 {
712 	char	c;
713 	int	num;
714 
715 	if (strp == NULL || !is_digit(c = *strp)) {
716 		errno = EINVAL;
717 		return NULL;
718 	}
719 	num = 0;
720 	do {
721 		num = num * 10 + (c - '0');
722 		if (num > max) {
723 			errno = EOVERFLOW;
724 			return NULL;	/* illegal value */
725 		}
726 		c = *++strp;
727 	} while (is_digit(c));
728 	if (num < min) {
729 		errno = EINVAL;
730 		return NULL;		/* illegal value */
731 	}
732 	*nump = num;
733 	return strp;
734 }
735 
736 /*
737 ** Given a pointer into a time zone string, extract a number of seconds,
738 ** in hh[:mm[:ss]] form, from the string.
739 ** If any error occurs, return NULL.
740 ** Otherwise, return a pointer to the first character not part of the number
741 ** of seconds.
742 */
743 
744 static const char *
745 getsecs(const char *strp, long *const secsp)
746 {
747 	int	num;
748 
749 	/*
750 	** `HOURSPERDAY * DAYSPERWEEK - 1' allows quasi-Posix rules like
751 	** "M10.4.6/26", which does not conform to Posix,
752 	** but which specifies the equivalent of
753 	** ``02:00 on the first Sunday on or after 23 Oct''.
754 	*/
755 	strp = getnum(strp, &num, 0, HOURSPERDAY * DAYSPERWEEK - 1);
756 	if (strp == NULL)
757 		return NULL;
758 	*secsp = num * (long) SECSPERHOUR;
759 	if (*strp == ':') {
760 		++strp;
761 		strp = getnum(strp, &num, 0, MINSPERHOUR - 1);
762 		if (strp == NULL)
763 			return NULL;
764 		*secsp += num * SECSPERMIN;
765 		if (*strp == ':') {
766 			++strp;
767 			/* `SECSPERMIN' allows for leap seconds. */
768 			strp = getnum(strp, &num, 0, SECSPERMIN);
769 			if (strp == NULL)
770 				return NULL;
771 			*secsp += num;
772 		}
773 	}
774 	return strp;
775 }
776 
777 /*
778 ** Given a pointer into a time zone string, extract an offset, in
779 ** [+-]hh[:mm[:ss]] form, from the string.
780 ** If any error occurs, return NULL.
781 ** Otherwise, return a pointer to the first character not part of the time.
782 */
783 
784 static const char *
785 getoffset(const char *strp, long *const offsetp)
786 {
787 	int	neg = 0;
788 
789 	if (*strp == '-') {
790 		neg = 1;
791 		++strp;
792 	} else if (*strp == '+')
793 		++strp;
794 	strp = getsecs(strp, offsetp);
795 	if (strp == NULL)
796 		return NULL;		/* illegal time */
797 	if (neg)
798 		*offsetp = -*offsetp;
799 	return strp;
800 }
801 
802 /*
803 ** Given a pointer into a time zone string, extract a rule in the form
804 ** date[/time]. See POSIX section 8 for the format of "date" and "time".
805 ** If a valid rule is not found, return NULL.
806 ** Otherwise, return a pointer to the first character not part of the rule.
807 */
808 
809 static const char *
810 getrule(const char *strp, struct rule *const rulep)
811 {
812 	if (*strp == 'J') {
813 		/*
814 		** Julian day.
815 		*/
816 		rulep->r_type = JULIAN_DAY;
817 		++strp;
818 		strp = getnum(strp, &rulep->r_day, 1, DAYSPERNYEAR);
819 	} else if (*strp == 'M') {
820 		/*
821 		** Month, week, day.
822 		*/
823 		rulep->r_type = MONTH_NTH_DAY_OF_WEEK;
824 		++strp;
825 		strp = getnum(strp, &rulep->r_mon, 1, MONSPERYEAR);
826 		if (strp == NULL)
827 			return NULL;
828 		if (*strp++ != '.')
829 			return NULL;
830 		strp = getnum(strp, &rulep->r_week, 1, 5);
831 		if (strp == NULL)
832 			return NULL;
833 		if (*strp++ != '.')
834 			return NULL;
835 		strp = getnum(strp, &rulep->r_day, 0, DAYSPERWEEK - 1);
836 	} else if (is_digit(*strp)) {
837 		/*
838 		** Day of year.
839 		*/
840 		rulep->r_type = DAY_OF_YEAR;
841 		strp = getnum(strp, &rulep->r_day, 0, DAYSPERLYEAR - 1);
842 	} else	return NULL;		/* invalid format */
843 	if (strp == NULL)
844 		return NULL;
845 	if (*strp == '/') {
846 		/*
847 		** Time specified.
848 		*/
849 		++strp;
850 		strp = getsecs(strp, &rulep->r_time);
851 	} else	rulep->r_time = 2 * SECSPERHOUR;	/* default = 2:00:00 */
852 	return strp;
853 }
854 
855 /*
856 ** Given the Epoch-relative time of January 1, 00:00:00 UTC, in a year, the
857 ** year, a rule, and the offset from UTC at the time that rule takes effect,
858 ** calculate the Epoch-relative time that rule takes effect.
859 */
860 
861 static time_t
862 transtime(const time_t janfirst, const int year, const struct rule *const rulep,
863     const long offset)
864 {
865 	int	leapyear;
866 	time_t	value;
867 	int	i;
868 	int		d, m1, yy0, yy1, yy2, dow;
869 
870 	INITIALIZE(value);
871 	leapyear = isleap(year);
872 	switch (rulep->r_type) {
873 
874 	case JULIAN_DAY:
875 		/*
876 		** Jn - Julian day, 1 == January 1, 60 == March 1 even in leap
877 		** years.
878 		** In non-leap years, or if the day number is 59 or less, just
879 		** add SECSPERDAY times the day number-1 to the time of
880 		** January 1, midnight, to get the day.
881 		*/
882 		value = janfirst + (rulep->r_day - 1) * SECSPERDAY;
883 		if (leapyear && rulep->r_day >= 60)
884 			value += SECSPERDAY;
885 		break;
886 
887 	case DAY_OF_YEAR:
888 		/*
889 		** n - day of year.
890 		** Just add SECSPERDAY times the day number to the time of
891 		** January 1, midnight, to get the day.
892 		*/
893 		value = janfirst + rulep->r_day * SECSPERDAY;
894 		break;
895 
896 	case MONTH_NTH_DAY_OF_WEEK:
897 		/*
898 		** Mm.n.d - nth "dth day" of month m.
899 		*/
900 		value = janfirst;
901 		for (i = 0; i < rulep->r_mon - 1; ++i)
902 			value += mon_lengths[leapyear][i] * SECSPERDAY;
903 
904 		/*
905 		** Use Zeller's Congruence to get day-of-week of first day of
906 		** month.
907 		*/
908 		m1 = (rulep->r_mon + 9) % 12 + 1;
909 		yy0 = (rulep->r_mon <= 2) ? (year - 1) : year;
910 		yy1 = yy0 / 100;
911 		yy2 = yy0 % 100;
912 		dow = ((26 * m1 - 2) / 10 +
913 			1 + yy2 + yy2 / 4 + yy1 / 4 - 2 * yy1) % 7;
914 		if (dow < 0)
915 			dow += DAYSPERWEEK;
916 
917 		/*
918 		** "dow" is the day-of-week of the first day of the month. Get
919 		** the day-of-month (zero-origin) of the first "dow" day of the
920 		** month.
921 		*/
922 		d = rulep->r_day - dow;
923 		if (d < 0)
924 			d += DAYSPERWEEK;
925 		for (i = 1; i < rulep->r_week; ++i) {
926 			if (d + DAYSPERWEEK >=
927 				mon_lengths[leapyear][rulep->r_mon - 1])
928 					break;
929 			d += DAYSPERWEEK;
930 		}
931 
932 		/*
933 		** "d" is the day-of-month (zero-origin) of the day we want.
934 		*/
935 		value += d * SECSPERDAY;
936 		break;
937 	}
938 
939 	/*
940 	** "value" is the Epoch-relative time of 00:00:00 UTC on the day in
941 	** question. To get the Epoch-relative time of the specified local
942 	** time on that day, add the transition time and the current offset
943 	** from UTC.
944 	*/
945 	return value + rulep->r_time + offset;
946 }
947 
948 /*
949 ** Given a POSIX section 8-style TZ string, fill in the rule tables as
950 ** appropriate.
951 */
952 
953 static int
954 tzparse(timezone_t sp, const char *name, const int lastditch)
955 {
956 	const char *			stdname;
957 	const char *			dstname;
958 	size_t				stdlen;
959 	size_t				dstlen;
960 	long				stdoffset;
961 	long				dstoffset;
962 	time_t *		atp;
963 	unsigned char *	typep;
964 	char *			cp;
965 	int			load_result;
966 
967 	INITIALIZE(dstname);
968 	stdname = name;
969 	if (lastditch) {
970 		stdlen = strlen(name);	/* length of standard zone name */
971 		name += stdlen;
972 		if (stdlen >= sizeof sp->chars)
973 			stdlen = (sizeof sp->chars) - 1;
974 		stdoffset = 0;
975 	} else {
976 		if (*name == '<') {
977 			name++;
978 			stdname = name;
979 			name = getqzname(name, '>');
980 			if (*name != '>')
981 				return (-1);
982 			stdlen = name - stdname;
983 			name++;
984 		} else {
985 			name = getzname(name);
986 			stdlen = name - stdname;
987 		}
988 		if (*name == '\0')
989 			return -1;
990 		name = getoffset(name, &stdoffset);
991 		if (name == NULL)
992 			return -1;
993 	}
994 	load_result = tzload(sp, TZDEFRULES, FALSE);
995 	if (load_result != 0)
996 		sp->leapcnt = 0;		/* so, we're off a little */
997 	if (*name != '\0') {
998 		if (*name == '<') {
999 			dstname = ++name;
1000 			name = getqzname(name, '>');
1001 			if (*name != '>')
1002 				return -1;
1003 			dstlen = name - dstname;
1004 			name++;
1005 		} else {
1006 			dstname = name;
1007 			name = getzname(name);
1008 			dstlen = name - dstname; /* length of DST zone name */
1009 		}
1010 		if (*name != '\0' && *name != ',' && *name != ';') {
1011 			name = getoffset(name, &dstoffset);
1012 			if (name == NULL)
1013 				return -1;
1014 		} else	dstoffset = stdoffset - SECSPERHOUR;
1015 		if (*name == '\0' && load_result != 0)
1016 			name = TZDEFRULESTRING;
1017 		if (*name == ',' || *name == ';') {
1018 			struct rule	start;
1019 			struct rule	end;
1020 			int	year;
1021 			time_t	janfirst;
1022 			time_t		starttime;
1023 			time_t		endtime;
1024 
1025 			++name;
1026 			if ((name = getrule(name, &start)) == NULL)
1027 				return -1;
1028 			if (*name++ != ',')
1029 				return -1;
1030 			if ((name = getrule(name, &end)) == NULL)
1031 				return -1;
1032 			if (*name != '\0')
1033 				return -1;
1034 			sp->typecnt = 2;	/* standard time and DST */
1035 			/*
1036 			** Two transitions per year, from EPOCH_YEAR forward.
1037 			*/
1038 			sp->ttis[0].tt_gmtoff = -dstoffset;
1039 			sp->ttis[0].tt_isdst = 1;
1040 			sp->ttis[0].tt_abbrind = stdlen + 1;
1041 			sp->ttis[1].tt_gmtoff = -stdoffset;
1042 			sp->ttis[1].tt_isdst = 0;
1043 			sp->ttis[1].tt_abbrind = 0;
1044 			atp = sp->ats;
1045 			typep = sp->types;
1046 			janfirst = 0;
1047 			sp->timecnt = 0;
1048 			for (year = EPOCH_YEAR;
1049 			    sp->timecnt + 2 <= TZ_MAX_TIMES;
1050 			    ++year) {
1051 			    	time_t	newfirst;
1052 
1053 				starttime = transtime(janfirst, year, &start,
1054 					stdoffset);
1055 				endtime = transtime(janfirst, year, &end,
1056 					dstoffset);
1057 				if (starttime > endtime) {
1058 					*atp++ = endtime;
1059 					*typep++ = 1;	/* DST ends */
1060 					*atp++ = starttime;
1061 					*typep++ = 0;	/* DST begins */
1062 				} else {
1063 					*atp++ = starttime;
1064 					*typep++ = 0;	/* DST begins */
1065 					*atp++ = endtime;
1066 					*typep++ = 1;	/* DST ends */
1067 				}
1068 				sp->timecnt += 2;
1069 				newfirst = janfirst;
1070 				newfirst += year_lengths[isleap(year)] *
1071 					SECSPERDAY;
1072 				if (newfirst <= janfirst)
1073 					break;
1074 				janfirst = newfirst;
1075 			}
1076 		} else {
1077 			long	theirstdoffset;
1078 			long	theirdstoffset;
1079 			long	theiroffset;
1080 			int	isdst;
1081 			int	i;
1082 			int	j;
1083 
1084 			if (*name != '\0')
1085 				return -1;
1086 			/*
1087 			** Initial values of theirstdoffset
1088 			*/
1089 			theirstdoffset = 0;
1090 			for (i = 0; i < sp->timecnt; ++i) {
1091 				j = sp->types[i];
1092 				if (!sp->ttis[j].tt_isdst) {
1093 					theirstdoffset =
1094 						-sp->ttis[j].tt_gmtoff;
1095 					break;
1096 				}
1097 			}
1098 			theirdstoffset = 0;
1099 			for (i = 0; i < sp->timecnt; ++i) {
1100 				j = sp->types[i];
1101 				if (sp->ttis[j].tt_isdst) {
1102 					theirdstoffset =
1103 						-sp->ttis[j].tt_gmtoff;
1104 					break;
1105 				}
1106 			}
1107 			/*
1108 			** Initially we're assumed to be in standard time.
1109 			*/
1110 			isdst = FALSE;
1111 			theiroffset = theirstdoffset;
1112 			/*
1113 			** Now juggle transition times and types
1114 			** tracking offsets as you do.
1115 			*/
1116 			for (i = 0; i < sp->timecnt; ++i) {
1117 				j = sp->types[i];
1118 				sp->types[i] = sp->ttis[j].tt_isdst;
1119 				if (sp->ttis[j].tt_ttisgmt) {
1120 					/* No adjustment to transition time */
1121 				} else {
1122 					/*
1123 					** If summer time is in effect, and the
1124 					** transition time was not specified as
1125 					** standard time, add the summer time
1126 					** offset to the transition time;
1127 					** otherwise, add the standard time
1128 					** offset to the transition time.
1129 					*/
1130 					/*
1131 					** Transitions from DST to DDST
1132 					** will effectively disappear since
1133 					** POSIX provides for only one DST
1134 					** offset.
1135 					*/
1136 					if (isdst && !sp->ttis[j].tt_ttisstd) {
1137 						sp->ats[i] += dstoffset -
1138 							theirdstoffset;
1139 					} else {
1140 						sp->ats[i] += stdoffset -
1141 							theirstdoffset;
1142 					}
1143 				}
1144 				theiroffset = -sp->ttis[j].tt_gmtoff;
1145 				if (!sp->ttis[j].tt_isdst)
1146 					theirstdoffset = theiroffset;
1147 				else	theirdstoffset = theiroffset;
1148 			}
1149 			/*
1150 			** Finally, fill in ttis.
1151 			** ttisstd and ttisgmt need not be handled.
1152 			*/
1153 			sp->ttis[0].tt_gmtoff = -stdoffset;
1154 			sp->ttis[0].tt_isdst = FALSE;
1155 			sp->ttis[0].tt_abbrind = 0;
1156 			sp->ttis[1].tt_gmtoff = -dstoffset;
1157 			sp->ttis[1].tt_isdst = TRUE;
1158 			sp->ttis[1].tt_abbrind = stdlen + 1;
1159 			sp->typecnt = 2;
1160 		}
1161 	} else {
1162 		dstlen = 0;
1163 		sp->typecnt = 1;		/* only standard time */
1164 		sp->timecnt = 0;
1165 		sp->ttis[0].tt_gmtoff = -stdoffset;
1166 		sp->ttis[0].tt_isdst = 0;
1167 		sp->ttis[0].tt_abbrind = 0;
1168 	}
1169 	sp->charcnt = stdlen + 1;
1170 	if (dstlen != 0)
1171 		sp->charcnt += dstlen + 1;
1172 	if ((size_t) sp->charcnt > sizeof sp->chars)
1173 		return -1;
1174 	cp = sp->chars;
1175 	(void) strncpy(cp, stdname, stdlen);
1176 	cp += stdlen;
1177 	*cp++ = '\0';
1178 	if (dstlen != 0) {
1179 		(void) strncpy(cp, dstname, dstlen);
1180 		*(cp + dstlen) = '\0';
1181 	}
1182 	return 0;
1183 }
1184 
1185 static void
1186 gmtload(timezone_t sp)
1187 {
1188 	if (tzload(sp, gmt, TRUE) != 0)
1189 		(void) tzparse(sp, gmt, TRUE);
1190 }
1191 
1192 timezone_t
1193 tzalloc(const char *name)
1194 {
1195 	timezone_t sp = calloc(1, sizeof *sp);
1196 	if (sp == NULL)
1197 		return NULL;
1198 	if (tzload(sp, name, TRUE) != 0) {
1199 		free(sp);
1200 		return NULL;
1201 	}
1202 	settzname_z(sp);
1203 	return sp;
1204 }
1205 
1206 void
1207 tzfree(const timezone_t sp)
1208 {
1209 	free(sp);
1210 }
1211 
1212 static void
1213 tzsetwall_unlocked(void)
1214 {
1215 	if (lcl_is_set < 0)
1216 		return;
1217 	lcl_is_set = -1;
1218 
1219 	if (lclptr == NULL) {
1220 		int saveerrno = errno;
1221 		lclptr = calloc(1, sizeof *lclptr);
1222 		errno = saveerrno;
1223 		if (lclptr == NULL) {
1224 			settzname();	/* all we can do */
1225 			return;
1226 		}
1227 	}
1228 	if (tzload(lclptr, NULL, TRUE) != 0)
1229 		gmtload(lclptr);
1230 	settzname();
1231 }
1232 
1233 #ifndef STD_INSPIRED
1234 /*
1235 ** A non-static declaration of tzsetwall in a system header file
1236 ** may cause a warning about this upcoming static declaration...
1237 */
1238 static
1239 #endif /* !defined STD_INSPIRED */
1240 void
1241 tzsetwall(void)
1242 {
1243 	rwlock_wrlock(&lcl_lock);
1244 	tzsetwall_unlocked();
1245 	rwlock_unlock(&lcl_lock);
1246 }
1247 
1248 #ifndef STD_INSPIRED
1249 /*
1250 ** A non-static declaration of tzsetwall in a system header file
1251 ** may cause a warning about this upcoming static declaration...
1252 */
1253 static
1254 #endif /* !defined STD_INSPIRED */
1255 void
1256 tzset_unlocked(void)
1257 {
1258 	const char *	name;
1259 	int saveerrno;
1260 
1261 	saveerrno = errno;
1262 	name = getenv("TZ");
1263 	errno = saveerrno;
1264 	if (name == NULL) {
1265 		tzsetwall_unlocked();
1266 		return;
1267 	}
1268 
1269 	if (lcl_is_set > 0 && strcmp(lcl_TZname, name) == 0)
1270 		return;
1271 	lcl_is_set = strlen(name) < sizeof lcl_TZname;
1272 	if (lcl_is_set)
1273 		(void)strlcpy(lcl_TZname, name, sizeof(lcl_TZname));
1274 
1275 	if (lclptr == NULL) {
1276 		saveerrno = errno;
1277 		lclptr = calloc(1, sizeof *lclptr);
1278 		errno = saveerrno;
1279 		if (lclptr == NULL) {
1280 			settzname();	/* all we can do */
1281 			return;
1282 		}
1283 	}
1284 	if (*name == '\0') {
1285 		/*
1286 		** User wants it fast rather than right.
1287 		*/
1288 		lclptr->leapcnt = 0;		/* so, we're off a little */
1289 		lclptr->timecnt = 0;
1290 		lclptr->typecnt = 0;
1291 		lclptr->ttis[0].tt_isdst = 0;
1292 		lclptr->ttis[0].tt_gmtoff = 0;
1293 		lclptr->ttis[0].tt_abbrind = 0;
1294 		(void) strlcpy(lclptr->chars, gmt, sizeof(lclptr->chars));
1295 	} else if (tzload(lclptr, name, TRUE) != 0)
1296 		if (name[0] == ':' || tzparse(lclptr, name, FALSE) != 0)
1297 			(void) gmtload(lclptr);
1298 	settzname();
1299 }
1300 
1301 void
1302 tzset(void)
1303 {
1304 	rwlock_wrlock(&lcl_lock);
1305 	tzset_unlocked();
1306 	rwlock_unlock(&lcl_lock);
1307 }
1308 
1309 /*
1310 ** The easy way to behave "as if no library function calls" localtime
1311 ** is to not call it--so we drop its guts into "localsub", which can be
1312 ** freely called. (And no, the PANS doesn't require the above behavior--
1313 ** but it *is* desirable.)
1314 **
1315 ** The unused offset argument is for the benefit of mktime variants.
1316 */
1317 
1318 /*ARGSUSED*/
1319 static struct tm *
1320 localsub(const timezone_t sp, const time_t * const timep, const long offset,
1321     struct tm *const tmp)
1322 {
1323 	const struct ttinfo *	ttisp;
1324 	int			i;
1325 	struct tm *		result;
1326 	const time_t			t = *timep;
1327 
1328 	if ((sp->goback && t < sp->ats[0]) ||
1329 		(sp->goahead && t > sp->ats[sp->timecnt - 1])) {
1330 			time_t			newt = t;
1331 			time_t		seconds;
1332 			time_t		tcycles;
1333 			int_fast64_t	icycles;
1334 
1335 			if (t < sp->ats[0])
1336 				seconds = sp->ats[0] - t;
1337 			else	seconds = t - sp->ats[sp->timecnt - 1];
1338 			--seconds;
1339 			tcycles = seconds / YEARSPERREPEAT / AVGSECSPERYEAR;
1340 			++tcycles;
1341 			icycles = tcycles;
1342 			if (tcycles - icycles >= 1 || icycles - tcycles >= 1)
1343 				return NULL;
1344 			seconds = (time_t) icycles;
1345 			seconds *= YEARSPERREPEAT;
1346 			seconds *= AVGSECSPERYEAR;
1347 			if (t < sp->ats[0])
1348 				newt += seconds;
1349 			else	newt -= seconds;
1350 			if (newt < sp->ats[0] ||
1351 				newt > sp->ats[sp->timecnt - 1])
1352 					return NULL;	/* "cannot happen" */
1353 			result = localsub(sp, &newt, offset, tmp);
1354 			if (result == tmp) {
1355 				time_t	newy;
1356 
1357 				newy = tmp->tm_year;
1358 				if (t < sp->ats[0])
1359 					newy -= (time_t)icycles * YEARSPERREPEAT;
1360 				else	newy += (time_t)icycles * YEARSPERREPEAT;
1361 				tmp->tm_year = (int)newy;
1362 				if (tmp->tm_year != newy)
1363 					return NULL;
1364 			}
1365 			return result;
1366 	}
1367 	if (sp->timecnt == 0 || t < sp->ats[0]) {
1368 		i = 0;
1369 		while (sp->ttis[i].tt_isdst)
1370 			if (++i >= sp->typecnt) {
1371 				i = 0;
1372 				break;
1373 			}
1374 	} else {
1375 		int	lo = 1;
1376 		int	hi = sp->timecnt;
1377 
1378 		while (lo < hi) {
1379 			int	mid = (lo + hi) / 2;
1380 
1381 			if (t < sp->ats[mid])
1382 				hi = mid;
1383 			else	lo = mid + 1;
1384 		}
1385 		i = (int) sp->types[lo - 1];
1386 	}
1387 	ttisp = &sp->ttis[i];
1388 	/*
1389 	** To get (wrong) behavior that's compatible with System V Release 2.0
1390 	** you'd replace the statement below with
1391 	**	t += ttisp->tt_gmtoff;
1392 	**	timesub(&t, 0L, sp, tmp);
1393 	*/
1394 	result = timesub(sp, &t, ttisp->tt_gmtoff, tmp);
1395 	tmp->tm_isdst = ttisp->tt_isdst;
1396 	tzname[tmp->tm_isdst] = &sp->chars[ttisp->tt_abbrind];
1397 #ifdef TM_ZONE
1398 	tmp->TM_ZONE = &sp->chars[ttisp->tt_abbrind];
1399 #endif /* defined TM_ZONE */
1400 	return result;
1401 }
1402 
1403 /*
1404 ** Re-entrant version of localtime.
1405 */
1406 
1407 struct tm *
1408 localtime_r(const time_t * __restrict timep, struct tm *tmp)
1409 {
1410 	rwlock_rdlock(&lcl_lock);
1411 	tzset_unlocked();
1412 	tmp = localtime_rz(lclptr, timep, tmp);
1413 	rwlock_unlock(&lcl_lock);
1414 	return tmp;
1415 }
1416 
1417 struct tm *
1418 localtime(const time_t *const timep)
1419 {
1420 	return localtime_r(timep, &tm);
1421 }
1422 
1423 struct tm *
1424 localtime_rz(const timezone_t sp, const time_t * __restrict timep, struct tm *tmp)
1425 {
1426 	if (sp == NULL)
1427 		tmp = gmtsub(NULL, timep, 0L, tmp);
1428 	else
1429 		tmp = localsub(sp, timep, 0L, tmp);
1430 	if (tmp == NULL)
1431 		errno = EOVERFLOW;
1432 	return tmp;
1433 }
1434 
1435 /*
1436 ** gmtsub is to gmtime as localsub is to localtime.
1437 */
1438 
1439 static struct tm *
1440 gmtsub(const timezone_t sp, const time_t * const timep, const long offset,
1441     struct tm *const tmp)
1442 {
1443 	struct tm *	result;
1444 #ifdef _REENTRANT
1445 	static mutex_t gmt_mutex = MUTEX_INITIALIZER;
1446 #endif
1447 
1448 	mutex_lock(&gmt_mutex);
1449 	if (!gmt_is_set) {
1450 		int saveerrno;
1451 		gmt_is_set = TRUE;
1452 		saveerrno = errno;
1453 		gmtptr = calloc(1, sizeof *gmtptr);
1454 		errno = saveerrno;
1455 		if (gmtptr != NULL)
1456 			gmtload(gmtptr);
1457 	}
1458 	mutex_unlock(&gmt_mutex);
1459 	result = timesub(gmtptr, timep, offset, tmp);
1460 #ifdef TM_ZONE
1461 	/*
1462 	** Could get fancy here and deliver something such as
1463 	** "UTC+xxxx" or "UTC-xxxx" if offset is non-zero,
1464 	** but this is no time for a treasure hunt.
1465 	*/
1466 	if (offset != 0)
1467 		tmp->TM_ZONE = (__aconst char *)__UNCONST(wildabbr);
1468 	else {
1469 		if (gmtptr == NULL)
1470 			tmp->TM_ZONE = (__aconst char *)__UNCONST(gmt);
1471 		else	tmp->TM_ZONE = gmtptr->chars;
1472 	}
1473 #endif /* defined TM_ZONE */
1474 	return result;
1475 }
1476 
1477 struct tm *
1478 gmtime(const time_t *const timep)
1479 {
1480 	return gmtsub(NULL, timep, 0L, &tm);
1481 }
1482 
1483 /*
1484 ** Re-entrant version of gmtime.
1485 */
1486 
1487 struct tm *
1488 gmtime_r(const time_t * const timep, struct tm *tmp)
1489 {
1490 	return gmtsub(NULL, timep, 0L, tmp);
1491 }
1492 
1493 #ifdef STD_INSPIRED
1494 
1495 struct tm *
1496 offtime(const time_t *const timep, long offset)
1497 {
1498 	return gmtsub(NULL, timep, offset, &tm);
1499 }
1500 
1501 struct tm *
1502 offtime_r(const time_t *timep, long offset, struct tm *tmp)
1503 {
1504 	return gmtsub(NULL, timep, offset, tmp);
1505 }
1506 
1507 #endif /* defined STD_INSPIRED */
1508 
1509 /*
1510 ** Return the number of leap years through the end of the given year
1511 ** where, to make the math easy, the answer for year zero is defined as zero.
1512 */
1513 
1514 static int
1515 leaps_thru_end_of(const int y)
1516 {
1517 	return (y >= 0) ? (y / 4 - y / 100 + y / 400) :
1518 		-(leaps_thru_end_of(-(y + 1)) + 1);
1519 }
1520 
1521 static struct tm *
1522 timesub(const timezone_t sp, const time_t *const timep, const long offset,
1523     struct tm *const tmp)
1524 {
1525 	const struct lsinfo *	lp;
1526 	time_t			tdays;
1527 	int			idays;	/* unsigned would be so 2003 */
1528 	long			rem;
1529 	int			y;
1530 	const int *		ip;
1531 	long			corr;
1532 	int			hit;
1533 	int			i;
1534 
1535 	corr = 0;
1536 	hit = 0;
1537 	i = (sp == NULL) ? 0 : sp->leapcnt;
1538 	while (--i >= 0) {
1539 		lp = &sp->lsis[i];
1540 		if (*timep >= lp->ls_trans) {
1541 			if (*timep == lp->ls_trans) {
1542 				hit = ((i == 0 && lp->ls_corr > 0) ||
1543 					lp->ls_corr > sp->lsis[i - 1].ls_corr);
1544 				if (hit)
1545 					while (i > 0 &&
1546 						sp->lsis[i].ls_trans ==
1547 						sp->lsis[i - 1].ls_trans + 1 &&
1548 						sp->lsis[i].ls_corr ==
1549 						sp->lsis[i - 1].ls_corr + 1) {
1550 							++hit;
1551 							--i;
1552 					}
1553 			}
1554 			corr = lp->ls_corr;
1555 			break;
1556 		}
1557 	}
1558 	y = EPOCH_YEAR;
1559 	tdays = *timep / SECSPERDAY;
1560 	rem = (long) (*timep - tdays * SECSPERDAY);
1561 	while (tdays < 0 || tdays >= year_lengths[isleap(y)]) {
1562 		int		newy;
1563 		time_t	tdelta;
1564 		int	idelta;
1565 		int	leapdays;
1566 
1567 		tdelta = tdays / DAYSPERLYEAR;
1568 		idelta = (int) tdelta;
1569 		if (tdelta - idelta >= 1 || idelta - tdelta >= 1)
1570 			return NULL;
1571 		if (idelta == 0)
1572 			idelta = (tdays < 0) ? -1 : 1;
1573 		newy = y;
1574 		if (increment_overflow(&newy, idelta))
1575 			return NULL;
1576 		leapdays = leaps_thru_end_of(newy - 1) -
1577 			leaps_thru_end_of(y - 1);
1578 		tdays -= ((time_t) newy - y) * DAYSPERNYEAR;
1579 		tdays -= leapdays;
1580 		y = newy;
1581 	}
1582 	{
1583 		long	seconds;
1584 
1585 		seconds = tdays * SECSPERDAY + 0.5;
1586 		tdays = seconds / SECSPERDAY;
1587 		rem += (long) (seconds - tdays * SECSPERDAY);
1588 	}
1589 	/*
1590 	** Given the range, we can now fearlessly cast...
1591 	*/
1592 	idays = (int) tdays;
1593 	rem += offset - corr;
1594 	while (rem < 0) {
1595 		rem += SECSPERDAY;
1596 		--idays;
1597 	}
1598 	while (rem >= SECSPERDAY) {
1599 		rem -= SECSPERDAY;
1600 		++idays;
1601 	}
1602 	while (idays < 0) {
1603 		if (increment_overflow(&y, -1))
1604 			return NULL;
1605 		idays += year_lengths[isleap(y)];
1606 	}
1607 	while (idays >= year_lengths[isleap(y)]) {
1608 		idays -= year_lengths[isleap(y)];
1609 		if (increment_overflow(&y, 1))
1610 			return NULL;
1611 	}
1612 	tmp->tm_year = y;
1613 	if (increment_overflow(&tmp->tm_year, -TM_YEAR_BASE))
1614 		return NULL;
1615 	tmp->tm_yday = idays;
1616 	/*
1617 	** The "extra" mods below avoid overflow problems.
1618 	*/
1619 	tmp->tm_wday = EPOCH_WDAY +
1620 		((y - EPOCH_YEAR) % DAYSPERWEEK) *
1621 		(DAYSPERNYEAR % DAYSPERWEEK) +
1622 		leaps_thru_end_of(y - 1) -
1623 		leaps_thru_end_of(EPOCH_YEAR - 1) +
1624 		idays;
1625 	tmp->tm_wday %= DAYSPERWEEK;
1626 	if (tmp->tm_wday < 0)
1627 		tmp->tm_wday += DAYSPERWEEK;
1628 	tmp->tm_hour = (int) (rem / SECSPERHOUR);
1629 	rem %= SECSPERHOUR;
1630 	tmp->tm_min = (int) (rem / SECSPERMIN);
1631 	/*
1632 	** A positive leap second requires a special
1633 	** representation. This uses "... ??:59:60" et seq.
1634 	*/
1635 	tmp->tm_sec = (int) (rem % SECSPERMIN) + hit;
1636 	ip = mon_lengths[isleap(y)];
1637 	for (tmp->tm_mon = 0; idays >= ip[tmp->tm_mon]; ++(tmp->tm_mon))
1638 		idays -= ip[tmp->tm_mon];
1639 	tmp->tm_mday = (int) (idays + 1);
1640 	tmp->tm_isdst = 0;
1641 #ifdef TM_GMTOFF
1642 	tmp->TM_GMTOFF = offset;
1643 #endif /* defined TM_GMTOFF */
1644 	return tmp;
1645 }
1646 
1647 char *
1648 ctime(const time_t *const timep)
1649 {
1650 /*
1651 ** Section 4.12.3.2 of X3.159-1989 requires that
1652 **	The ctime function converts the calendar time pointed to by timer
1653 **	to local time in the form of a string. It is equivalent to
1654 **		asctime(localtime(timer))
1655 */
1656 	struct tm *rtm = localtime(timep);
1657 	if (rtm == NULL)
1658 		return NULL;
1659 	return asctime(rtm);
1660 }
1661 
1662 char *
1663 ctime_r(const time_t *const timep, char *buf)
1664 {
1665 	struct tm	mytm, *rtm;
1666 
1667 	rtm = localtime_r(timep, &mytm);
1668 	if (rtm == NULL)
1669 		return NULL;
1670 	return asctime_r(rtm, buf);
1671 }
1672 
1673 char *
1674 ctime_rz(const timezone_t sp, const time_t * timep, char *buf)
1675 {
1676 	struct tm	mytm, *rtm;
1677 
1678 	rtm = localtime_rz(sp, timep, &mytm);
1679 	if (rtm == NULL)
1680 		return NULL;
1681 	return asctime_r(rtm, buf);
1682 }
1683 
1684 /*
1685 ** Adapted from code provided by Robert Elz, who writes:
1686 **	The "best" way to do mktime I think is based on an idea of Bob
1687 **	Kridle's (so its said...) from a long time ago.
1688 **	It does a binary search of the time_t space. Since time_t's are
1689 **	just 32 bits, its a max of 32 iterations (even at 64 bits it
1690 **	would still be very reasonable).
1691 */
1692 
1693 #ifndef WRONG
1694 #define WRONG	((time_t)-1)
1695 #endif /* !defined WRONG */
1696 
1697 /*
1698 ** Simplified normalize logic courtesy Paul Eggert.
1699 */
1700 
1701 static int
1702 increment_overflow(int *number, int delta)
1703 {
1704 	int	number0;
1705 
1706 	number0 = *number;
1707 	if (delta < 0 ? number0 < INT_MIN - delta : INT_MAX - delta < number0)
1708 		  return 1;
1709 	*number += delta;
1710 	return 0;
1711 }
1712 
1713 static int
1714 long_increment_overflow(long *number, int delta)
1715 {
1716 	long	number0;
1717 
1718 	number0 = *number;
1719 	if (delta < 0 ? number0 < LONG_MIN - delta : LONG_MAX - delta < number0)
1720 		  return 1;
1721 	*number += delta;
1722 	return 0;
1723 }
1724 
1725 static int
1726 normalize_overflow(int *const tensptr, int *const unitsptr, const int base)
1727 {
1728 	int	tensdelta;
1729 
1730 	tensdelta = (*unitsptr >= 0) ?
1731 		(*unitsptr / base) :
1732 		(-1 - (-1 - *unitsptr) / base);
1733 	*unitsptr -= tensdelta * base;
1734 	return increment_overflow(tensptr, tensdelta);
1735 }
1736 
1737 static int
1738 long_normalize_overflow(long *const tensptr, int *const unitsptr,
1739     const int base)
1740 {
1741 	int	tensdelta;
1742 
1743 	tensdelta = (*unitsptr >= 0) ?
1744 		(*unitsptr / base) :
1745 		(-1 - (-1 - *unitsptr) / base);
1746 	*unitsptr -= tensdelta * base;
1747 	return long_increment_overflow(tensptr, tensdelta);
1748 }
1749 
1750 static int
1751 tmcomp(const struct tm *const atmp, const struct tm *const btmp)
1752 {
1753 	int	result;
1754 
1755 	if ((result = (atmp->tm_year - btmp->tm_year)) == 0 &&
1756 		(result = (atmp->tm_mon - btmp->tm_mon)) == 0 &&
1757 		(result = (atmp->tm_mday - btmp->tm_mday)) == 0 &&
1758 		(result = (atmp->tm_hour - btmp->tm_hour)) == 0 &&
1759 		(result = (atmp->tm_min - btmp->tm_min)) == 0)
1760 			result = atmp->tm_sec - btmp->tm_sec;
1761 	return result;
1762 }
1763 
1764 static time_t
1765 time2sub(const timezone_t sp, struct tm *const tmp, subfun_t funcp,
1766     const long offset, int *const okayp, const int do_norm_secs)
1767 {
1768 	int			dir;
1769 	int			i, j;
1770 	int			saved_seconds;
1771 	long			li;
1772 	time_t			lo;
1773 	time_t			hi;
1774 	long				y;
1775 	time_t				newt;
1776 	time_t				t;
1777 	struct tm			yourtm, mytm;
1778 
1779 	*okayp = FALSE;
1780 	yourtm = *tmp;
1781 	if (do_norm_secs) {
1782 		if (normalize_overflow(&yourtm.tm_min, &yourtm.tm_sec,
1783 			SECSPERMIN))
1784 				return WRONG;
1785 	}
1786 	if (normalize_overflow(&yourtm.tm_hour, &yourtm.tm_min, MINSPERHOUR))
1787 		return WRONG;
1788 	if (normalize_overflow(&yourtm.tm_mday, &yourtm.tm_hour, HOURSPERDAY))
1789 		return WRONG;
1790 	y = yourtm.tm_year;
1791 	if (long_normalize_overflow(&y, &yourtm.tm_mon, MONSPERYEAR))
1792 		return WRONG;
1793 	/*
1794 	** Turn y into an actual year number for now.
1795 	** It is converted back to an offset from TM_YEAR_BASE later.
1796 	*/
1797 	if (long_increment_overflow(&y, TM_YEAR_BASE))
1798 		return WRONG;
1799 	while (yourtm.tm_mday <= 0) {
1800 		if (long_increment_overflow(&y, -1))
1801 			return WRONG;
1802 		li = y + (1 < yourtm.tm_mon);
1803 		yourtm.tm_mday += year_lengths[isleap(li)];
1804 	}
1805 	while (yourtm.tm_mday > DAYSPERLYEAR) {
1806 		li = y + (1 < yourtm.tm_mon);
1807 		yourtm.tm_mday -= year_lengths[isleap(li)];
1808 		if (long_increment_overflow(&y, 1))
1809 			return WRONG;
1810 	}
1811 	for ( ; ; ) {
1812 		i = mon_lengths[isleap(y)][yourtm.tm_mon];
1813 		if (yourtm.tm_mday <= i)
1814 			break;
1815 		yourtm.tm_mday -= i;
1816 		if (++yourtm.tm_mon >= MONSPERYEAR) {
1817 			yourtm.tm_mon = 0;
1818 			if (long_increment_overflow(&y, 1))
1819 				return WRONG;
1820 		}
1821 	}
1822 	if (long_increment_overflow(&y, -TM_YEAR_BASE))
1823 		return WRONG;
1824 	yourtm.tm_year = y;
1825 	if (yourtm.tm_year != y)
1826 		return WRONG;
1827 	if (yourtm.tm_sec >= 0 && yourtm.tm_sec < SECSPERMIN)
1828 		saved_seconds = 0;
1829 	else if (y + TM_YEAR_BASE < EPOCH_YEAR) {
1830 		/*
1831 		** We can't set tm_sec to 0, because that might push the
1832 		** time below the minimum representable time.
1833 		** Set tm_sec to 59 instead.
1834 		** This assumes that the minimum representable time is
1835 		** not in the same minute that a leap second was deleted from,
1836 		** which is a safer assumption than using 58 would be.
1837 		*/
1838 		if (increment_overflow(&yourtm.tm_sec, 1 - SECSPERMIN))
1839 			return WRONG;
1840 		saved_seconds = yourtm.tm_sec;
1841 		yourtm.tm_sec = SECSPERMIN - 1;
1842 	} else {
1843 		saved_seconds = yourtm.tm_sec;
1844 		yourtm.tm_sec = 0;
1845 	}
1846 	/*
1847 	** Do a binary search (this works whatever time_t's type is).
1848 	*/
1849 /* LINTED constant */
1850 	if (!TYPE_SIGNED(time_t)) {
1851 		lo = 0;
1852 		hi = lo - 1;
1853 /* LINTED constant */
1854 	} else if (!TYPE_INTEGRAL(time_t)) {
1855 /* CONSTCOND */
1856 		if (sizeof(time_t) > sizeof(float))
1857 /* LINTED assumed double */
1858 			hi = (time_t) DBL_MAX;
1859 /* LINTED assumed float */
1860 		else	hi = (time_t) FLT_MAX;
1861 		lo = -hi;
1862 	} else {
1863 		lo = 1;
1864 		for (i = 0; i < (int) TYPE_BIT(time_t) - 1; ++i)
1865 			lo *= 2;
1866 		hi = -(lo + 1);
1867 	}
1868 	for ( ; ; ) {
1869 		t = lo / 2 + hi / 2;
1870 		if (t < lo)
1871 			t = lo;
1872 		else if (t > hi)
1873 			t = hi;
1874 		if ((*funcp)(sp, &t, offset, &mytm) == NULL) {
1875 			/*
1876 			** Assume that t is too extreme to be represented in
1877 			** a struct tm; arrange things so that it is less
1878 			** extreme on the next pass.
1879 			*/
1880 			dir = (t > 0) ? 1 : -1;
1881 		} else	dir = tmcomp(&mytm, &yourtm);
1882 		if (dir != 0) {
1883 			if (t == lo) {
1884 				++t;
1885 				if (t <= lo)
1886 					return WRONG;
1887 				++lo;
1888 			} else if (t == hi) {
1889 				--t;
1890 				if (t >= hi)
1891 					return WRONG;
1892 				--hi;
1893 			}
1894 			if (lo > hi)
1895 				return WRONG;
1896 			if (dir > 0)
1897 				hi = t;
1898 			else	lo = t;
1899 			continue;
1900 		}
1901 		if (yourtm.tm_isdst < 0 || mytm.tm_isdst == yourtm.tm_isdst)
1902 			break;
1903 		/*
1904 		** Right time, wrong type.
1905 		** Hunt for right time, right type.
1906 		** It's okay to guess wrong since the guess
1907 		** gets checked.
1908 		*/
1909 		if (sp == NULL)
1910 			return WRONG;
1911 		for (i = sp->typecnt - 1; i >= 0; --i) {
1912 			if (sp->ttis[i].tt_isdst != yourtm.tm_isdst)
1913 				continue;
1914 			for (j = sp->typecnt - 1; j >= 0; --j) {
1915 				if (sp->ttis[j].tt_isdst == yourtm.tm_isdst)
1916 					continue;
1917 				newt = t + sp->ttis[j].tt_gmtoff -
1918 					sp->ttis[i].tt_gmtoff;
1919 				if ((*funcp)(sp, &newt, offset, &mytm) == NULL)
1920 					continue;
1921 				if (tmcomp(&mytm, &yourtm) != 0)
1922 					continue;
1923 				if (mytm.tm_isdst != yourtm.tm_isdst)
1924 					continue;
1925 				/*
1926 				** We have a match.
1927 				*/
1928 				t = newt;
1929 				goto label;
1930 			}
1931 		}
1932 		return WRONG;
1933 	}
1934 label:
1935 	newt = t + saved_seconds;
1936 	if ((newt < t) != (saved_seconds < 0))
1937 		return WRONG;
1938 	t = newt;
1939 	if ((*funcp)(sp, &t, offset, tmp)) {
1940 		*okayp = TRUE;
1941 		return t;
1942 	} else
1943 		return WRONG;
1944 }
1945 
1946 static time_t
1947 time2(const timezone_t sp, struct tm *const tmp, subfun_t funcp,
1948     const long offset, int *const okayp)
1949 {
1950 	time_t	t;
1951 
1952 	/*
1953 	** First try without normalization of seconds
1954 	** (in case tm_sec contains a value associated with a leap second).
1955 	** If that fails, try with normalization of seconds.
1956 	*/
1957 	t = time2sub(sp, tmp, funcp, offset, okayp, FALSE);
1958 	return *okayp ? t : time2sub(sp, tmp, funcp, offset, okayp, TRUE);
1959 }
1960 
1961 static time_t
1962 time1(const timezone_t sp, struct tm *const tmp, subfun_t funcp,
1963     long offset)
1964 {
1965 	time_t			t;
1966 	int			samei, otheri;
1967 	int			sameind, otherind;
1968 	int			i;
1969 	int			nseen;
1970 	int				seen[TZ_MAX_TYPES];
1971 	int				types[TZ_MAX_TYPES];
1972 	int				okay;
1973 
1974 	if (tmp->tm_isdst > 1)
1975 		tmp->tm_isdst = 1;
1976 	t = time2(sp, tmp, funcp, offset, &okay);
1977 #ifdef PCTS
1978 	/*
1979 	** PCTS code courtesy Grant Sullivan.
1980 	*/
1981 	if (okay)
1982 		return t;
1983 	if (tmp->tm_isdst < 0)
1984 		tmp->tm_isdst = 0;	/* reset to std and try again */
1985 #endif /* defined PCTS */
1986 #ifndef PCTS
1987 	if (okay || tmp->tm_isdst < 0)
1988 		return t;
1989 #endif /* !defined PCTS */
1990 	/*
1991 	** We're supposed to assume that somebody took a time of one type
1992 	** and did some math on it that yielded a "struct tm" that's bad.
1993 	** We try to divine the type they started from and adjust to the
1994 	** type they need.
1995 	*/
1996 	if (sp == NULL)
1997 		return WRONG;
1998 	for (i = 0; i < sp->typecnt; ++i)
1999 		seen[i] = FALSE;
2000 	nseen = 0;
2001 	for (i = sp->timecnt - 1; i >= 0; --i)
2002 		if (!seen[sp->types[i]]) {
2003 			seen[sp->types[i]] = TRUE;
2004 			types[nseen++] = sp->types[i];
2005 		}
2006 	for (sameind = 0; sameind < nseen; ++sameind) {
2007 		samei = types[sameind];
2008 		if (sp->ttis[samei].tt_isdst != tmp->tm_isdst)
2009 			continue;
2010 		for (otherind = 0; otherind < nseen; ++otherind) {
2011 			otheri = types[otherind];
2012 			if (sp->ttis[otheri].tt_isdst == tmp->tm_isdst)
2013 				continue;
2014 			tmp->tm_sec += (int)(sp->ttis[otheri].tt_gmtoff -
2015 					sp->ttis[samei].tt_gmtoff);
2016 			tmp->tm_isdst = !tmp->tm_isdst;
2017 			t = time2(sp, tmp, funcp, offset, &okay);
2018 			if (okay)
2019 				return t;
2020 			tmp->tm_sec -= (int)(sp->ttis[otheri].tt_gmtoff -
2021 					sp->ttis[samei].tt_gmtoff);
2022 			tmp->tm_isdst = !tmp->tm_isdst;
2023 		}
2024 	}
2025 	return WRONG;
2026 }
2027 
2028 time_t
2029 mktime_z(const timezone_t sp, struct tm *tmp)
2030 {
2031 	time_t t;
2032 	if (sp == NULL)
2033 		t = time1(NULL, tmp, gmtsub, 0L);
2034 	else
2035 		t = time1(sp, tmp, localsub, 0L);
2036 	if (t == WRONG)
2037 		errno = EOVERFLOW;
2038 	return t;
2039 }
2040 
2041 time_t
2042 mktime(struct tm * const	tmp)
2043 {
2044 	time_t result;
2045 
2046 	rwlock_wrlock(&lcl_lock);
2047 	tzset_unlocked();
2048 	result = mktime_z(lclptr, tmp);
2049 	rwlock_unlock(&lcl_lock);
2050 	return result;
2051 }
2052 
2053 #ifdef STD_INSPIRED
2054 
2055 time_t
2056 timelocal_z(const timezone_t sp, struct tm *tmp)
2057 {
2058 	if (tmp != NULL)
2059 		tmp->tm_isdst = -1;	/* in case it wasn't initialized */
2060 	return mktime_z(sp, tmp);
2061 }
2062 
2063 time_t
2064 timelocal(struct tm *const tmp)
2065 {
2066 	tmp->tm_isdst = -1;	/* in case it wasn't initialized */
2067 	return mktime(tmp);
2068 }
2069 
2070 time_t
2071 timegm(struct tm *const tmp)
2072 {
2073 	time_t t;
2074 
2075 	tmp->tm_isdst = 0;
2076 	t = time1(gmtptr, tmp, gmtsub, 0L);
2077 	if (t == WRONG)
2078 		errno = EOVERFLOW;
2079 	return t;
2080 }
2081 
2082 time_t
2083 timeoff(struct tm *const tmp, const long offset)
2084 {
2085 	time_t t;
2086 
2087 	tmp->tm_isdst = 0;
2088 	t = time1(gmtptr, tmp, gmtsub, offset);
2089 	if (t == WRONG)
2090 		errno = EOVERFLOW;
2091 	return t;
2092 }
2093 
2094 #endif /* defined STD_INSPIRED */
2095 
2096 #ifdef CMUCS
2097 
2098 /*
2099 ** The following is supplied for compatibility with
2100 ** previous versions of the CMUCS runtime library.
2101 */
2102 
2103 long
2104 gtime(struct tm *const tmp)
2105 {
2106 	const time_t t = mktime(tmp);
2107 
2108 	if (t == WRONG)
2109 		return -1;
2110 	return t;
2111 }
2112 
2113 #endif /* defined CMUCS */
2114 
2115 /*
2116 ** XXX--is the below the right way to conditionalize??
2117 */
2118 
2119 #ifdef STD_INSPIRED
2120 
2121 /*
2122 ** IEEE Std 1003.1-1988 (POSIX) legislates that 536457599
2123 ** shall correspond to "Wed Dec 31 23:59:59 UTC 1986", which
2124 ** is not the case if we are accounting for leap seconds.
2125 ** So, we provide the following conversion routines for use
2126 ** when exchanging timestamps with POSIX conforming systems.
2127 */
2128 
2129 static long
2130 leapcorr(const timezone_t sp, time_t *timep)
2131 {
2132 	struct lsinfo * lp;
2133 	int		i;
2134 
2135 	i = sp->leapcnt;
2136 	while (--i >= 0) {
2137 		lp = &sp->lsis[i];
2138 		if (*timep >= lp->ls_trans)
2139 			return lp->ls_corr;
2140 	}
2141 	return 0;
2142 }
2143 
2144 time_t
2145 time2posix_z(const timezone_t sp, time_t t)
2146 {
2147 	return t - leapcorr(sp, &t);
2148 }
2149 
2150 time_t
2151 time2posix(time_t t)
2152 {
2153 	time_t result;
2154 	rwlock_wrlock(&lcl_lock);
2155 	tzset_unlocked();
2156 	result = t - leapcorr(lclptr, &t);
2157 	rwlock_unlock(&lcl_lock);
2158 	return (result);
2159 }
2160 
2161 time_t
2162 posix2time_z(const timezone_t sp, time_t t)
2163 {
2164 	time_t	x;
2165 	time_t	y;
2166 
2167 	/*
2168 	** For a positive leap second hit, the result
2169 	** is not unique. For a negative leap second
2170 	** hit, the corresponding time doesn't exist,
2171 	** so we return an adjacent second.
2172 	*/
2173 	x = t + leapcorr(sp, &t);
2174 	y = x - leapcorr(sp, &x);
2175 	if (y < t) {
2176 		do {
2177 			x++;
2178 			y = x - leapcorr(sp, &x);
2179 		} while (y < t);
2180 		if (t != y) {
2181 			return x - 1;
2182 		}
2183 	} else if (y > t) {
2184 		do {
2185 			--x;
2186 			y = x - leapcorr(sp, &x);
2187 		} while (y > t);
2188 		if (t != y) {
2189 			return x + 1;
2190 		}
2191 	}
2192 	return x;
2193 }
2194 
2195 
2196 
2197 time_t
2198 posix2time(time_t t)
2199 {
2200 	time_t result;
2201 
2202 	rwlock_wrlock(&lcl_lock);
2203 	tzset_unlocked();
2204 	result = posix2time_z(lclptr, t);
2205 	rwlock_unlock(&lcl_lock);
2206 	return result;
2207 }
2208 
2209 #endif /* defined STD_INSPIRED */
2210