xref: /netbsd-src/lib/libc/time/localtime.c (revision 3816d47b2c42fcd6e549e3407f842a5b1a1d23ad)
1 /*	$NetBSD: localtime.c,v 1.45 2009/12/31 22:49:16 mlelstv 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 1.45 2009/12/31 22:49:16 mlelstv 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(daylight,_daylight)
32 __weak_alias(tzname,_tzname)
33 __weak_alias(tzset,_tzset)
34 __weak_alias(tzsetwall,_tzsetwall)
35 #endif
36 
37 #include "float.h"	/* for FLT_MAX and DBL_MAX */
38 
39 #ifndef TZ_ABBR_MAX_LEN
40 #define TZ_ABBR_MAX_LEN	16
41 #endif /* !defined TZ_ABBR_MAX_LEN */
42 
43 #ifndef TZ_ABBR_CHAR_SET
44 #define TZ_ABBR_CHAR_SET \
45 	"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789 :+-._"
46 #endif /* !defined TZ_ABBR_CHAR_SET */
47 
48 #ifndef TZ_ABBR_ERR_CHAR
49 #define TZ_ABBR_ERR_CHAR	'_'
50 #endif /* !defined TZ_ABBR_ERR_CHAR */
51 
52 /*
53 ** SunOS 4.1.1 headers lack O_BINARY.
54 */
55 
56 #ifdef O_BINARY
57 #define OPEN_MODE	(O_RDONLY | O_BINARY)
58 #endif /* defined O_BINARY */
59 #ifndef O_BINARY
60 #define OPEN_MODE	O_RDONLY
61 #endif /* !defined O_BINARY */
62 
63 #ifndef WILDABBR
64 /*
65 ** Someone might make incorrect use of a time zone abbreviation:
66 **	1.	They might reference tzname[0] before calling tzset (explicitly
67 **		or implicitly).
68 **	2.	They might reference tzname[1] before calling tzset (explicitly
69 **		or implicitly).
70 **	3.	They might reference tzname[1] after setting to a time zone
71 **		in which Daylight Saving Time is never observed.
72 **	4.	They might reference tzname[0] after setting to a time zone
73 **		in which Standard Time is never observed.
74 **	5.	They might reference tm.TM_ZONE after calling offtime.
75 ** What's best to do in the above cases is open to debate;
76 ** for now, we just set things up so that in any of the five cases
77 ** WILDABBR is used. Another possibility: initialize tzname[0] to the
78 ** string "tzname[0] used before set", and similarly for the other cases.
79 ** And another: initialize tzname[0] to "ERA", with an explanation in the
80 ** manual page of what this "time zone abbreviation" means (doing this so
81 ** that tzname[0] has the "normal" length of three characters).
82 */
83 #define WILDABBR	"   "
84 #endif /* !defined WILDABBR */
85 
86 static const char	wildabbr[] = WILDABBR;
87 
88 static const char	gmt[] = "GMT";
89 
90 /*
91 ** The DST rules to use if TZ has no rules and we can't load TZDEFRULES.
92 ** We default to US rules as of 1999-08-17.
93 ** POSIX 1003.1 section 8.1.1 says that the default DST rules are
94 ** implementation dependent; for historical reasons, US rules are a
95 ** common default.
96 */
97 #ifndef TZDEFRULESTRING
98 #define TZDEFRULESTRING ",M4.1.0,M10.5.0"
99 #endif /* !defined TZDEFDST */
100 
101 struct ttinfo {				/* time type information */
102 	long		tt_gmtoff;	/* UTC offset in seconds */
103 	int		tt_isdst;	/* used to set tm_isdst */
104 	int		tt_abbrind;	/* abbreviation list index */
105 	int		tt_ttisstd;	/* TRUE if transition is std time */
106 	int		tt_ttisgmt;	/* TRUE if transition is UTC */
107 };
108 
109 struct lsinfo {				/* leap second information */
110 	time_t		ls_trans;	/* transition time */
111 	long		ls_corr;	/* correction to apply */
112 };
113 
114 #define BIGGEST(a, b)	(((a) > (b)) ? (a) : (b))
115 
116 #ifdef TZNAME_MAX
117 #define MY_TZNAME_MAX	TZNAME_MAX
118 #endif /* defined TZNAME_MAX */
119 #ifndef TZNAME_MAX
120 #define MY_TZNAME_MAX	255
121 #endif /* !defined TZNAME_MAX */
122 
123 struct state {
124 	int		leapcnt;
125 	int		timecnt;
126 	int		typecnt;
127 	int		charcnt;
128 	int		goback;
129 	int		goahead;
130 	time_t		ats[TZ_MAX_TIMES];
131 	unsigned char	types[TZ_MAX_TIMES];
132 	struct ttinfo	ttis[TZ_MAX_TYPES];
133 	char		chars[/*CONSTCOND*/BIGGEST(BIGGEST(TZ_MAX_CHARS + 1, sizeof gmt),
134 				(2 * (MY_TZNAME_MAX + 1)))];
135 	struct lsinfo	lsis[TZ_MAX_LEAPS];
136 };
137 
138 struct rule {
139 	int		r_type;		/* type of rule--see below */
140 	int		r_day;		/* day number of rule */
141 	int		r_week;		/* week number of rule */
142 	int		r_mon;		/* month number of rule */
143 	long		r_time;		/* transition time of rule */
144 };
145 
146 #define JULIAN_DAY		0	/* Jn - Julian day */
147 #define DAY_OF_YEAR		1	/* n - day of year */
148 #define MONTH_NTH_DAY_OF_WEEK	2	/* Mm.n.d - month, week, day of week */
149 
150 /*
151 ** Prototypes for static functions.
152 */
153 
154 static long		detzcode(const char * codep);
155 static time_t		detzcode64(const char * codep);
156 static int		differ_by_repeat(time_t t1, time_t t0);
157 static const char *	getzname(const char * strp);
158 static const char *	getqzname(const char * strp, const int delim);
159 static const char *	getnum(const char * strp, int * nump, int min,
160 				int max);
161 static const char *	getsecs(const char * strp, long * secsp);
162 static const char *	getoffset(const char * strp, long * offsetp);
163 static const char *	getrule(const char * strp, struct rule * rulep);
164 static void		gmtload(struct state * sp);
165 static struct tm *	gmtsub(const time_t * timep, long offset,
166 				struct tm * tmp);
167 static struct tm *	localsub(const time_t * timep, long offset,
168 				struct tm * tmp);
169 static int		increment_overflow(int * number, int delta);
170 static int		leaps_thru_end_of(int y);
171 static int		long_increment_overflow(long * number, int delta);
172 static int		long_normalize_overflow(long * tensptr,
173 				int * unitsptr, int base);
174 static int		normalize_overflow(int * tensptr, int * unitsptr,
175 				int base);
176 static void		settzname(void);
177 static time_t		time1(struct tm * tmp,
178 				struct tm * (*funcp)(const time_t *,
179 				long, struct tm *),
180 				long offset);
181 static time_t		time2(struct tm *tmp,
182 				struct tm * (*funcp)(const time_t *,
183 				long, struct tm*),
184 				long offset, int * okayp);
185 static time_t		time2sub(struct tm *tmp,
186 				struct tm * (*funcp)(const time_t *,
187 				long, struct tm*),
188 				long offset, int * okayp, int do_norm_secs);
189 static struct tm *	timesub(const time_t * timep, long offset,
190 				const struct state * sp, struct tm * tmp);
191 static int		tmcomp(const struct tm * atmp,
192 				const struct tm * btmp);
193 static time_t		transtime(time_t janfirst, int year,
194 				const struct rule * rulep, long offset);
195 static int		typesequiv(const struct state * sp, int a, int b);
196 static int		tzload(const char * name, struct state * sp,
197 				int doextend);
198 static int		tzparse(const char * name, struct state * sp,
199 				int lastditch);
200 static void		tzset_unlocked(void);
201 static void		tzsetwall_unlocked(void);
202 static long		leapcorr(time_t * timep);
203 
204 #ifdef ALL_STATE
205 static struct state *	lclptr;
206 static struct state *	gmtptr;
207 #endif /* defined ALL_STATE */
208 
209 #ifndef ALL_STATE
210 static struct state	lclmem;
211 static struct state	gmtmem;
212 #define lclptr		(&lclmem)
213 #define gmtptr		(&gmtmem)
214 #endif /* State Farm */
215 
216 #ifndef TZ_STRLEN_MAX
217 #define TZ_STRLEN_MAX 255
218 #endif /* !defined TZ_STRLEN_MAX */
219 
220 static char		lcl_TZname[TZ_STRLEN_MAX + 1];
221 static int		lcl_is_set;
222 static int		gmt_is_set;
223 
224 #if !defined(__LIBC12_SOURCE__)
225 
226 __aconst char *		tzname[2] = {
227 	(__aconst char *)__UNCONST(wildabbr),
228 	(__aconst char *)__UNCONST(wildabbr)
229 };
230 
231 #else
232 
233 extern __aconst char *	tzname[2];
234 
235 #endif
236 
237 #ifdef _REENTRANT
238 static rwlock_t lcl_lock = RWLOCK_INITIALIZER;
239 #endif
240 
241 /*
242 ** Section 4.12.3 of X3.159-1989 requires that
243 **	Except for the strftime function, these functions [asctime,
244 **	ctime, gmtime, localtime] return values in one of two static
245 **	objects: a broken-down time structure and an array of char.
246 ** Thanks to Paul Eggert for noting this.
247 */
248 
249 static struct tm	tm;
250 
251 #ifdef USG_COMPAT
252 #if !defined(__LIBC12_SOURCE__)
253 long 			timezone = 0;
254 int			daylight = 0;
255 #else
256 extern int		daylight;
257 extern long		timezone __RENAME(__timezone13);
258 #endif
259 #endif /* defined USG_COMPAT */
260 
261 #ifdef ALTZONE
262 time_t			altzone = 0;
263 #endif /* defined ALTZONE */
264 
265 static long
266 detzcode(codep)
267 const char * const	codep;
268 {
269 	register long	result;
270 	register int	i;
271 
272 	result = (codep[0] & 0x80) ? ~0L : 0;
273 	for (i = 0; i < 4; ++i)
274 		result = (result << 8) | (codep[i] & 0xff);
275 	return result;
276 }
277 
278 static time_t
279 detzcode64(codep)
280 const char * const	codep;
281 {
282 	register time_t	result;
283 	register int	i;
284 
285 	result = (codep[0] & 0x80) ? -1 : 0;
286 	for (i = 0; i < 8; ++i)
287 		result = result * 256 + (codep[i] & 0xff);
288 	return result;
289 }
290 
291 static void
292 settzname(void)
293 {
294 	register struct state * const	sp = lclptr;
295 	register int			i;
296 
297 	tzname[0] = (__aconst char *)__UNCONST(wildabbr);
298 	tzname[1] = (__aconst char *)__UNCONST(wildabbr);
299 #ifdef USG_COMPAT
300 	daylight = 0;
301 	timezone = 0;
302 #endif /* defined USG_COMPAT */
303 #ifdef ALTZONE
304 	altzone = 0;
305 #endif /* defined ALTZONE */
306 #ifdef ALL_STATE
307 	if (sp == NULL) {
308 		tzname[0] = tzname[1] = (__aconst char *)__UNCONST(gmt);
309 		return;
310 	}
311 #endif /* defined ALL_STATE */
312 	for (i = 0; i < sp->typecnt; ++i) {
313 		register const struct ttinfo * const	ttisp = &sp->ttis[i];
314 
315 		tzname[ttisp->tt_isdst] =
316 			&sp->chars[ttisp->tt_abbrind];
317 #ifdef USG_COMPAT
318 		if (ttisp->tt_isdst)
319 			daylight = 1;
320 		if (i == 0 || !ttisp->tt_isdst)
321 			timezone = -(ttisp->tt_gmtoff);
322 #endif /* defined USG_COMPAT */
323 #ifdef ALTZONE
324 		if (i == 0 || ttisp->tt_isdst)
325 			altzone = -(ttisp->tt_gmtoff);
326 #endif /* defined ALTZONE */
327 	}
328 	/*
329 	** And to get the latest zone names into tzname. . .
330 	*/
331 	for (i = 0; i < sp->timecnt; ++i) {
332 		register const struct ttinfo * const	ttisp =
333 							&sp->ttis[
334 								sp->types[i]];
335 
336 		tzname[ttisp->tt_isdst] =
337 			&sp->chars[ttisp->tt_abbrind];
338 	}
339 	/*
340 	** Finally, scrub the abbreviations.
341 	** First, replace bogus characters.
342 	*/
343 	for (i = 0; i < sp->charcnt; ++i)
344 		if (strchr(TZ_ABBR_CHAR_SET, sp->chars[i]) == NULL)
345 			sp->chars[i] = TZ_ABBR_ERR_CHAR;
346 	/*
347 	** Second, truncate long abbreviations.
348 	*/
349 	for (i = 0; i < sp->typecnt; ++i) {
350 		register const struct ttinfo * const	ttisp = &sp->ttis[i];
351 		register char *				cp = &sp->chars[ttisp->tt_abbrind];
352 
353 		if (strlen(cp) > TZ_ABBR_MAX_LEN &&
354 			strcmp(cp, GRANDPARENTED) != 0)
355 				*(cp + TZ_ABBR_MAX_LEN) = '\0';
356 	}
357 }
358 
359 static int
360 differ_by_repeat(t1, t0)
361 const time_t	t1;
362 const time_t	t0;
363 {
364 /* CONSTCOND */
365 	if (TYPE_INTEGRAL(time_t) &&
366 		TYPE_BIT(time_t) - TYPE_SIGNED(time_t) < SECSPERREPEAT_BITS)
367 			return 0;
368 	return (int_fast64_t)t1 - (int_fast64_t)t0 == SECSPERREPEAT;
369 }
370 
371 static int
372 tzload(name, sp, doextend)
373 register const char *		name;
374 register struct state * const	sp;
375 register const int		doextend;
376 {
377 	register const char *		p;
378 	register int			i;
379 	register int			fid;
380 	register int			stored;
381 	register int			nread;
382 	union {
383 		struct tzhead	tzhead;
384 		char		buf[2 * sizeof(struct tzhead) +
385 					2 * sizeof *sp +
386 					4 * TZ_MAX_TIMES];
387 	} u;
388 
389 	if (name == NULL && (name = TZDEFAULT) == NULL)
390 		return -1;
391 	{
392 		register int	doaccess;
393 		/*
394 		** Section 4.9.1 of the C standard says that
395 		** "FILENAME_MAX expands to an integral constant expression
396 		** that is the size needed for an array of char large enough
397 		** to hold the longest file name string that the implementation
398 		** guarantees can be opened."
399 		*/
400 		char		fullname[FILENAME_MAX + 1];
401 
402 		if (name[0] == ':')
403 			++name;
404 		doaccess = name[0] == '/';
405 		if (!doaccess) {
406 			if ((p = TZDIR) == NULL)
407 				return -1;
408 			if ((strlen(p) + strlen(name) + 1) >= sizeof fullname)
409 				return -1;
410 			(void) strcpy(fullname, p);	/* XXX strcpy is safe */
411 			(void) strcat(fullname, "/");	/* XXX strcat is safe */
412 			(void) strcat(fullname, name);	/* XXX strcat is safe */
413 			/*
414 			** Set doaccess if '.' (as in "../") shows up in name.
415 			*/
416 			if (strchr(name, '.') != NULL)
417 				doaccess = TRUE;
418 			name = fullname;
419 		}
420 		if (doaccess && access(name, R_OK) != 0)
421 			return -1;
422 		/*
423 		 * XXX potential security problem here if user of a set-id
424 		 * program has set TZ (which is passed in as name) here,
425 		 * and uses a race condition trick to defeat the access(2)
426 		 * above.
427 		 */
428 		if ((fid = open(name, OPEN_MODE)) == -1)
429 			return -1;
430 	}
431 	nread = read(fid, u.buf, sizeof u.buf);
432 	if (close(fid) < 0 || nread <= 0)
433 		return -1;
434 	for (stored = 4; stored <= 8; stored *= 2) {
435 		int		ttisstdcnt;
436 		int		ttisgmtcnt;
437 
438 		ttisstdcnt = (int) detzcode(u.tzhead.tzh_ttisstdcnt);
439 		ttisgmtcnt = (int) detzcode(u.tzhead.tzh_ttisgmtcnt);
440 		sp->leapcnt = (int) detzcode(u.tzhead.tzh_leapcnt);
441 		sp->timecnt = (int) detzcode(u.tzhead.tzh_timecnt);
442 		sp->typecnt = (int) detzcode(u.tzhead.tzh_typecnt);
443 		sp->charcnt = (int) detzcode(u.tzhead.tzh_charcnt);
444 		p = u.tzhead.tzh_charcnt + sizeof u.tzhead.tzh_charcnt;
445 		if (sp->leapcnt < 0 || sp->leapcnt > TZ_MAX_LEAPS ||
446 			sp->typecnt <= 0 || sp->typecnt > TZ_MAX_TYPES ||
447 			sp->timecnt < 0 || sp->timecnt > TZ_MAX_TIMES ||
448 			sp->charcnt < 0 || sp->charcnt > TZ_MAX_CHARS ||
449 			(ttisstdcnt != sp->typecnt && ttisstdcnt != 0) ||
450 			(ttisgmtcnt != sp->typecnt && ttisgmtcnt != 0))
451 				return -1;
452 		if (nread - (p - u.buf) <
453 			sp->timecnt * stored +		/* ats */
454 			sp->timecnt +			/* types */
455 			sp->typecnt * 6 +		/* ttinfos */
456 			sp->charcnt +			/* chars */
457 			sp->leapcnt * (stored + 4) +	/* lsinfos */
458 			ttisstdcnt +			/* ttisstds */
459 			ttisgmtcnt)			/* ttisgmts */
460 				return -1;
461 		for (i = 0; i < sp->timecnt; ++i) {
462 			sp->ats[i] = (stored == 4) ?
463 				detzcode(p) : detzcode64(p);
464 			p += stored;
465 		}
466 		for (i = 0; i < sp->timecnt; ++i) {
467 			sp->types[i] = (unsigned char) *p++;
468 			if (sp->types[i] >= sp->typecnt)
469 				return -1;
470 		}
471 		for (i = 0; i < sp->typecnt; ++i) {
472 			register struct ttinfo *	ttisp;
473 
474 			ttisp = &sp->ttis[i];
475 			ttisp->tt_gmtoff = detzcode(p);
476 			p += 4;
477 			ttisp->tt_isdst = (unsigned char) *p++;
478 			if (ttisp->tt_isdst != 0 && ttisp->tt_isdst != 1)
479 				return -1;
480 			ttisp->tt_abbrind = (unsigned char) *p++;
481 			if (ttisp->tt_abbrind < 0 ||
482 				ttisp->tt_abbrind > sp->charcnt)
483 					return -1;
484 		}
485 		for (i = 0; i < sp->charcnt; ++i)
486 			sp->chars[i] = *p++;
487 		sp->chars[i] = '\0';	/* ensure '\0' at end */
488 		for (i = 0; i < sp->leapcnt; ++i) {
489 			register struct lsinfo *	lsisp;
490 
491 			lsisp = &sp->lsis[i];
492 			lsisp->ls_trans = (stored == 4) ?
493 				detzcode(p) : detzcode64(p);
494 			p += stored;
495 			lsisp->ls_corr = detzcode(p);
496 			p += 4;
497 		}
498 		for (i = 0; i < sp->typecnt; ++i) {
499 			register struct ttinfo *	ttisp;
500 
501 			ttisp = &sp->ttis[i];
502 			if (ttisstdcnt == 0)
503 				ttisp->tt_ttisstd = FALSE;
504 			else {
505 				ttisp->tt_ttisstd = *p++;
506 				if (ttisp->tt_ttisstd != TRUE &&
507 					ttisp->tt_ttisstd != FALSE)
508 						return -1;
509 			}
510 		}
511 		for (i = 0; i < sp->typecnt; ++i) {
512 			register struct ttinfo *	ttisp;
513 
514 			ttisp = &sp->ttis[i];
515 			if (ttisgmtcnt == 0)
516 				ttisp->tt_ttisgmt = FALSE;
517 			else {
518 				ttisp->tt_ttisgmt = *p++;
519 				if (ttisp->tt_ttisgmt != TRUE &&
520 					ttisp->tt_ttisgmt != FALSE)
521 						return -1;
522 			}
523 		}
524 		/*
525 		** Out-of-sort ats should mean we're running on a
526 		** signed time_t system but using a data file with
527 		** unsigned values (or vice versa).
528 		*/
529 		for (i = 0; i < sp->timecnt - 2; ++i)
530 			if (sp->ats[i] > sp->ats[i + 1]) {
531 				++i;
532 /* CONSTCOND */
533 				if (TYPE_SIGNED(time_t)) {
534 					/*
535 					** Ignore the end (easy).
536 					*/
537 					sp->timecnt = i;
538 				} else {
539 					/*
540 					** Ignore the beginning (harder).
541 					*/
542 					register int	j;
543 
544 					for (j = 0; j + i < sp->timecnt; ++j) {
545 						sp->ats[j] = sp->ats[j + i];
546 						sp->types[j] = sp->types[j + i];
547 					}
548 					sp->timecnt = j;
549 				}
550 				break;
551 			}
552 		/*
553 		** If this is an old file, we're done.
554 		*/
555 		if (u.tzhead.tzh_version[0] == '\0')
556 			break;
557 		nread -= p - u.buf;
558 		for (i = 0; i < nread; ++i)
559 			u.buf[i] = p[i];
560 		/*
561 		** If this is a narrow integer time_t system, we're done.
562 		*/
563 		if (stored >= (int) sizeof(time_t)
564 /* CONSTCOND */
565 				&& TYPE_INTEGRAL(time_t))
566 			break;
567 	}
568 	if (doextend && nread > 2 &&
569 		u.buf[0] == '\n' && u.buf[nread - 1] == '\n' &&
570 		sp->typecnt + 2 <= TZ_MAX_TYPES) {
571 			struct state	ts;
572 			register int	result;
573 
574 			u.buf[nread - 1] = '\0';
575 			result = tzparse(&u.buf[1], &ts, FALSE);
576 			if (result == 0 && ts.typecnt == 2 &&
577 				sp->charcnt + ts.charcnt <= TZ_MAX_CHARS) {
578 					for (i = 0; i < 2; ++i)
579 						ts.ttis[i].tt_abbrind +=
580 							sp->charcnt;
581 					for (i = 0; i < ts.charcnt; ++i)
582 						sp->chars[sp->charcnt++] =
583 							ts.chars[i];
584 					i = 0;
585 					while (i < ts.timecnt &&
586 						ts.ats[i] <=
587 						sp->ats[sp->timecnt - 1])
588 							++i;
589 					while (i < ts.timecnt &&
590 					    sp->timecnt < TZ_MAX_TIMES) {
591 						sp->ats[sp->timecnt] =
592 							ts.ats[i];
593 						sp->types[sp->timecnt] =
594 							sp->typecnt +
595 							ts.types[i];
596 						++sp->timecnt;
597 						++i;
598 					}
599 					sp->ttis[sp->typecnt++] = ts.ttis[0];
600 					sp->ttis[sp->typecnt++] = ts.ttis[1];
601 			}
602 	}
603 	sp->goback = sp->goahead = FALSE;
604 	if (sp->timecnt > 1) {
605 		for (i = 1; i < sp->timecnt; ++i)
606 			if (typesequiv(sp, sp->types[i], sp->types[0]) &&
607 				differ_by_repeat(sp->ats[i], sp->ats[0])) {
608 					sp->goback = TRUE;
609 					break;
610 				}
611 		for (i = sp->timecnt - 2; i >= 0; --i)
612 			if (typesequiv(sp, sp->types[sp->timecnt - 1],
613 				sp->types[i]) &&
614 				differ_by_repeat(sp->ats[sp->timecnt - 1],
615 				sp->ats[i])) {
616 					sp->goahead = TRUE;
617 					break;
618 		}
619 	}
620 	return 0;
621 }
622 
623 static int
624 typesequiv(sp, a, b)
625 const struct state * const	sp;
626 const int			a;
627 const int			b;
628 {
629 	register int	result;
630 
631 	if (sp == NULL ||
632 		a < 0 || a >= sp->typecnt ||
633 		b < 0 || b >= sp->typecnt)
634 			result = FALSE;
635 	else {
636 		register const struct ttinfo *	ap = &sp->ttis[a];
637 		register const struct ttinfo *	bp = &sp->ttis[b];
638 		result = ap->tt_gmtoff == bp->tt_gmtoff &&
639 			ap->tt_isdst == bp->tt_isdst &&
640 			ap->tt_ttisstd == bp->tt_ttisstd &&
641 			ap->tt_ttisgmt == bp->tt_ttisgmt &&
642 			strcmp(&sp->chars[ap->tt_abbrind],
643 			&sp->chars[bp->tt_abbrind]) == 0;
644 	}
645 	return result;
646 }
647 
648 static const int	mon_lengths[2][MONSPERYEAR] = {
649 	{ 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 },
650 	{ 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }
651 };
652 
653 static const int	year_lengths[2] = {
654 	DAYSPERNYEAR, DAYSPERLYEAR
655 };
656 
657 /*
658 ** Given a pointer into a time zone string, scan until a character that is not
659 ** a valid character in a zone name is found. Return a pointer to that
660 ** character.
661 */
662 
663 static const char *
664 getzname(strp)
665 register const char *	strp;
666 {
667 	register char	c;
668 
669 	while ((c = *strp) != '\0' && !is_digit(c) && c != ',' && c != '-' &&
670 		c != '+')
671 			++strp;
672 	return strp;
673 }
674 
675 /*
676 ** Given a pointer into an extended time zone string, scan until the ending
677 ** delimiter of the zone name is located. Return a pointer to the delimiter.
678 **
679 ** As with getzname above, the legal character set is actually quite
680 ** restricted, with other characters producing undefined results.
681 ** We don't do any checking here; checking is done later in common-case code.
682 */
683 
684 static const char *
685 getqzname(register const char *strp, const int delim)
686 {
687 	register int	c;
688 
689 	while ((c = *strp) != '\0' && c != delim)
690 		++strp;
691 	return strp;
692 }
693 
694 /*
695 ** Given a pointer into a time zone string, extract a number from that string.
696 ** Check that the number is within a specified range; if it is not, return
697 ** NULL.
698 ** Otherwise, return a pointer to the first character not part of the number.
699 */
700 
701 static const char *
702 getnum(strp, nump, min, max)
703 register const char *	strp;
704 int * const		nump;
705 const int		min;
706 const int		max;
707 {
708 	register char	c;
709 	register int	num;
710 
711 	if (strp == NULL || !is_digit(c = *strp))
712 		return NULL;
713 	num = 0;
714 	do {
715 		num = num * 10 + (c - '0');
716 		if (num > max)
717 			return NULL;	/* illegal value */
718 		c = *++strp;
719 	} while (is_digit(c));
720 	if (num < min)
721 		return NULL;		/* illegal value */
722 	*nump = num;
723 	return strp;
724 }
725 
726 /*
727 ** Given a pointer into a time zone string, extract a number of seconds,
728 ** in hh[:mm[:ss]] form, from the string.
729 ** If any error occurs, return NULL.
730 ** Otherwise, return a pointer to the first character not part of the number
731 ** of seconds.
732 */
733 
734 static const char *
735 getsecs(strp, secsp)
736 register const char *	strp;
737 long * const		secsp;
738 {
739 	int	num;
740 
741 	/*
742 	** `HOURSPERDAY * DAYSPERWEEK - 1' allows quasi-Posix rules like
743 	** "M10.4.6/26", which does not conform to Posix,
744 	** but which specifies the equivalent of
745 	** ``02:00 on the first Sunday on or after 23 Oct''.
746 	*/
747 	strp = getnum(strp, &num, 0, HOURSPERDAY * DAYSPERWEEK - 1);
748 	if (strp == NULL)
749 		return NULL;
750 	*secsp = num * (long) SECSPERHOUR;
751 	if (*strp == ':') {
752 		++strp;
753 		strp = getnum(strp, &num, 0, MINSPERHOUR - 1);
754 		if (strp == NULL)
755 			return NULL;
756 		*secsp += num * SECSPERMIN;
757 		if (*strp == ':') {
758 			++strp;
759 			/* `SECSPERMIN' allows for leap seconds. */
760 			strp = getnum(strp, &num, 0, SECSPERMIN);
761 			if (strp == NULL)
762 				return NULL;
763 			*secsp += num;
764 		}
765 	}
766 	return strp;
767 }
768 
769 /*
770 ** Given a pointer into a time zone string, extract an offset, in
771 ** [+-]hh[:mm[:ss]] form, from the string.
772 ** If any error occurs, return NULL.
773 ** Otherwise, return a pointer to the first character not part of the time.
774 */
775 
776 static const char *
777 getoffset(strp, offsetp)
778 register const char *	strp;
779 long * const		offsetp;
780 {
781 	register int	neg = 0;
782 
783 	if (*strp == '-') {
784 		neg = 1;
785 		++strp;
786 	} else if (*strp == '+')
787 		++strp;
788 	strp = getsecs(strp, offsetp);
789 	if (strp == NULL)
790 		return NULL;		/* illegal time */
791 	if (neg)
792 		*offsetp = -*offsetp;
793 	return strp;
794 }
795 
796 /*
797 ** Given a pointer into a time zone string, extract a rule in the form
798 ** date[/time]. See POSIX section 8 for the format of "date" and "time".
799 ** If a valid rule is not found, return NULL.
800 ** Otherwise, return a pointer to the first character not part of the rule.
801 */
802 
803 static const char *
804 getrule(strp, rulep)
805 const char *			strp;
806 register struct rule * const	rulep;
807 {
808 	if (*strp == 'J') {
809 		/*
810 		** Julian day.
811 		*/
812 		rulep->r_type = JULIAN_DAY;
813 		++strp;
814 		strp = getnum(strp, &rulep->r_day, 1, DAYSPERNYEAR);
815 	} else if (*strp == 'M') {
816 		/*
817 		** Month, week, day.
818 		*/
819 		rulep->r_type = MONTH_NTH_DAY_OF_WEEK;
820 		++strp;
821 		strp = getnum(strp, &rulep->r_mon, 1, MONSPERYEAR);
822 		if (strp == NULL)
823 			return NULL;
824 		if (*strp++ != '.')
825 			return NULL;
826 		strp = getnum(strp, &rulep->r_week, 1, 5);
827 		if (strp == NULL)
828 			return NULL;
829 		if (*strp++ != '.')
830 			return NULL;
831 		strp = getnum(strp, &rulep->r_day, 0, DAYSPERWEEK - 1);
832 	} else if (is_digit(*strp)) {
833 		/*
834 		** Day of year.
835 		*/
836 		rulep->r_type = DAY_OF_YEAR;
837 		strp = getnum(strp, &rulep->r_day, 0, DAYSPERLYEAR - 1);
838 	} else	return NULL;		/* invalid format */
839 	if (strp == NULL)
840 		return NULL;
841 	if (*strp == '/') {
842 		/*
843 		** Time specified.
844 		*/
845 		++strp;
846 		strp = getsecs(strp, &rulep->r_time);
847 	} else	rulep->r_time = 2 * SECSPERHOUR;	/* default = 2:00:00 */
848 	return strp;
849 }
850 
851 /*
852 ** Given the Epoch-relative time of January 1, 00:00:00 UTC, in a year, the
853 ** year, a rule, and the offset from UTC at the time that rule takes effect,
854 ** calculate the Epoch-relative time that rule takes effect.
855 */
856 
857 static time_t
858 transtime(janfirst, year, rulep, offset)
859 const time_t				janfirst;
860 const int				year;
861 register const struct rule * const	rulep;
862 const long				offset;
863 {
864 	register int	leapyear;
865 	register time_t	value;
866 	register int	i;
867 	int		d, m1, yy0, yy1, yy2, dow;
868 
869 	INITIALIZE(value);
870 	leapyear = isleap(year);
871 	switch (rulep->r_type) {
872 
873 	case JULIAN_DAY:
874 		/*
875 		** Jn - Julian day, 1 == January 1, 60 == March 1 even in leap
876 		** years.
877 		** In non-leap years, or if the day number is 59 or less, just
878 		** add SECSPERDAY times the day number-1 to the time of
879 		** January 1, midnight, to get the day.
880 		*/
881 		value = janfirst + (rulep->r_day - 1) * SECSPERDAY;
882 		if (leapyear && rulep->r_day >= 60)
883 			value += SECSPERDAY;
884 		break;
885 
886 	case DAY_OF_YEAR:
887 		/*
888 		** n - day of year.
889 		** Just add SECSPERDAY times the day number to the time of
890 		** January 1, midnight, to get the day.
891 		*/
892 		value = janfirst + rulep->r_day * SECSPERDAY;
893 		break;
894 
895 	case MONTH_NTH_DAY_OF_WEEK:
896 		/*
897 		** Mm.n.d - nth "dth day" of month m.
898 		*/
899 		value = janfirst;
900 		for (i = 0; i < rulep->r_mon - 1; ++i)
901 			value += mon_lengths[leapyear][i] * SECSPERDAY;
902 
903 		/*
904 		** Use Zeller's Congruence to get day-of-week of first day of
905 		** month.
906 		*/
907 		m1 = (rulep->r_mon + 9) % 12 + 1;
908 		yy0 = (rulep->r_mon <= 2) ? (year - 1) : year;
909 		yy1 = yy0 / 100;
910 		yy2 = yy0 % 100;
911 		dow = ((26 * m1 - 2) / 10 +
912 			1 + yy2 + yy2 / 4 + yy1 / 4 - 2 * yy1) % 7;
913 		if (dow < 0)
914 			dow += DAYSPERWEEK;
915 
916 		/*
917 		** "dow" is the day-of-week of the first day of the month. Get
918 		** the day-of-month (zero-origin) of the first "dow" day of the
919 		** month.
920 		*/
921 		d = rulep->r_day - dow;
922 		if (d < 0)
923 			d += DAYSPERWEEK;
924 		for (i = 1; i < rulep->r_week; ++i) {
925 			if (d + DAYSPERWEEK >=
926 				mon_lengths[leapyear][rulep->r_mon - 1])
927 					break;
928 			d += DAYSPERWEEK;
929 		}
930 
931 		/*
932 		** "d" is the day-of-month (zero-origin) of the day we want.
933 		*/
934 		value += d * SECSPERDAY;
935 		break;
936 	}
937 
938 	/*
939 	** "value" is the Epoch-relative time of 00:00:00 UTC on the day in
940 	** question. To get the Epoch-relative time of the specified local
941 	** time on that day, add the transition time and the current offset
942 	** from UTC.
943 	*/
944 	return value + rulep->r_time + offset;
945 }
946 
947 /*
948 ** Given a POSIX section 8-style TZ string, fill in the rule tables as
949 ** appropriate.
950 */
951 
952 static int
953 tzparse(name, sp, lastditch)
954 const char *			name;
955 register struct state * const	sp;
956 const int			lastditch;
957 {
958 	const char *			stdname;
959 	const char *			dstname;
960 	size_t				stdlen;
961 	size_t				dstlen;
962 	long				stdoffset;
963 	long				dstoffset;
964 	register time_t *		atp;
965 	register unsigned char *	typep;
966 	register char *			cp;
967 	register int			load_result;
968 
969 	INITIALIZE(dstname);
970 	stdname = name;
971 	if (lastditch) {
972 		stdlen = strlen(name);	/* length of standard zone name */
973 		name += stdlen;
974 		if (stdlen >= sizeof sp->chars)
975 			stdlen = (sizeof sp->chars) - 1;
976 		stdoffset = 0;
977 	} else {
978 		if (*name == '<') {
979 			name++;
980 			stdname = name;
981 			name = getqzname(name, '>');
982 			if (*name != '>')
983 				return (-1);
984 			stdlen = name - stdname;
985 			name++;
986 		} else {
987 			name = getzname(name);
988 			stdlen = name - stdname;
989 		}
990 		if (*name == '\0')
991 			return -1;
992 		name = getoffset(name, &stdoffset);
993 		if (name == NULL)
994 			return -1;
995 	}
996 	load_result = tzload(TZDEFRULES, sp, FALSE);
997 	if (load_result != 0)
998 		sp->leapcnt = 0;		/* so, we're off a little */
999 	if (*name != '\0') {
1000 		if (*name == '<') {
1001 			dstname = ++name;
1002 			name = getqzname(name, '>');
1003 			if (*name != '>')
1004 				return -1;
1005 			dstlen = name - dstname;
1006 			name++;
1007 		} else {
1008 			dstname = name;
1009 			name = getzname(name);
1010 			dstlen = name - dstname; /* length of DST zone name */
1011 		}
1012 		if (*name != '\0' && *name != ',' && *name != ';') {
1013 			name = getoffset(name, &dstoffset);
1014 			if (name == NULL)
1015 				return -1;
1016 		} else	dstoffset = stdoffset - SECSPERHOUR;
1017 		if (*name == '\0' && load_result != 0)
1018 			name = TZDEFRULESTRING;
1019 		if (*name == ',' || *name == ';') {
1020 			struct rule	start;
1021 			struct rule	end;
1022 			register int	year;
1023 			register time_t	janfirst;
1024 			time_t		starttime;
1025 			time_t		endtime;
1026 
1027 			++name;
1028 			if ((name = getrule(name, &start)) == NULL)
1029 				return -1;
1030 			if (*name++ != ',')
1031 				return -1;
1032 			if ((name = getrule(name, &end)) == NULL)
1033 				return -1;
1034 			if (*name != '\0')
1035 				return -1;
1036 			sp->typecnt = 2;	/* standard time and DST */
1037 			/*
1038 			** Two transitions per year, from EPOCH_YEAR forward.
1039 			*/
1040 			sp->ttis[0].tt_gmtoff = -dstoffset;
1041 			sp->ttis[0].tt_isdst = 1;
1042 			sp->ttis[0].tt_abbrind = stdlen + 1;
1043 			sp->ttis[1].tt_gmtoff = -stdoffset;
1044 			sp->ttis[1].tt_isdst = 0;
1045 			sp->ttis[1].tt_abbrind = 0;
1046 			atp = sp->ats;
1047 			typep = sp->types;
1048 			janfirst = 0;
1049 			sp->timecnt = 0;
1050 			for (year = EPOCH_YEAR;
1051 			    sp->timecnt + 2 <= TZ_MAX_TIMES;
1052 			    ++year) {
1053 			    	time_t	newfirst;
1054 
1055 				starttime = transtime(janfirst, year, &start,
1056 					stdoffset);
1057 				endtime = transtime(janfirst, year, &end,
1058 					dstoffset);
1059 				if (starttime > endtime) {
1060 					*atp++ = endtime;
1061 					*typep++ = 1;	/* DST ends */
1062 					*atp++ = starttime;
1063 					*typep++ = 0;	/* DST begins */
1064 				} else {
1065 					*atp++ = starttime;
1066 					*typep++ = 0;	/* DST begins */
1067 					*atp++ = endtime;
1068 					*typep++ = 1;	/* DST ends */
1069 				}
1070 				sp->timecnt += 2;
1071 				newfirst = janfirst;
1072 				newfirst += year_lengths[isleap(year)] *
1073 					SECSPERDAY;
1074 				if (newfirst <= janfirst)
1075 					break;
1076 				janfirst = newfirst;
1077 			}
1078 		} else {
1079 			register long	theirstdoffset;
1080 			register long	theirdstoffset;
1081 			register long	theiroffset;
1082 			register int	isdst;
1083 			register int	i;
1084 			register int	j;
1085 
1086 			if (*name != '\0')
1087 				return -1;
1088 			/*
1089 			** Initial values of theirstdoffset
1090 			*/
1091 			theirstdoffset = 0;
1092 			for (i = 0; i < sp->timecnt; ++i) {
1093 				j = sp->types[i];
1094 				if (!sp->ttis[j].tt_isdst) {
1095 					theirstdoffset =
1096 						-sp->ttis[j].tt_gmtoff;
1097 					break;
1098 				}
1099 			}
1100 			theirdstoffset = 0;
1101 			for (i = 0; i < sp->timecnt; ++i) {
1102 				j = sp->types[i];
1103 				if (sp->ttis[j].tt_isdst) {
1104 					theirdstoffset =
1105 						-sp->ttis[j].tt_gmtoff;
1106 					break;
1107 				}
1108 			}
1109 			/*
1110 			** Initially we're assumed to be in standard time.
1111 			*/
1112 			isdst = FALSE;
1113 			theiroffset = theirstdoffset;
1114 			/*
1115 			** Now juggle transition times and types
1116 			** tracking offsets as you do.
1117 			*/
1118 			for (i = 0; i < sp->timecnt; ++i) {
1119 				j = sp->types[i];
1120 				sp->types[i] = sp->ttis[j].tt_isdst;
1121 				if (sp->ttis[j].tt_ttisgmt) {
1122 					/* No adjustment to transition time */
1123 				} else {
1124 					/*
1125 					** If summer time is in effect, and the
1126 					** transition time was not specified as
1127 					** standard time, add the summer time
1128 					** offset to the transition time;
1129 					** otherwise, add the standard time
1130 					** offset to the transition time.
1131 					*/
1132 					/*
1133 					** Transitions from DST to DDST
1134 					** will effectively disappear since
1135 					** POSIX provides for only one DST
1136 					** offset.
1137 					*/
1138 					if (isdst && !sp->ttis[j].tt_ttisstd) {
1139 						sp->ats[i] += dstoffset -
1140 							theirdstoffset;
1141 					} else {
1142 						sp->ats[i] += stdoffset -
1143 							theirstdoffset;
1144 					}
1145 				}
1146 				theiroffset = -sp->ttis[j].tt_gmtoff;
1147 				if (!sp->ttis[j].tt_isdst)
1148 					theirstdoffset = theiroffset;
1149 				else	theirdstoffset = theiroffset;
1150 			}
1151 			/*
1152 			** Finally, fill in ttis.
1153 			** ttisstd and ttisgmt need not be handled.
1154 			*/
1155 			sp->ttis[0].tt_gmtoff = -stdoffset;
1156 			sp->ttis[0].tt_isdst = FALSE;
1157 			sp->ttis[0].tt_abbrind = 0;
1158 			sp->ttis[1].tt_gmtoff = -dstoffset;
1159 			sp->ttis[1].tt_isdst = TRUE;
1160 			sp->ttis[1].tt_abbrind = stdlen + 1;
1161 			sp->typecnt = 2;
1162 		}
1163 	} else {
1164 		dstlen = 0;
1165 		sp->typecnt = 1;		/* only standard time */
1166 		sp->timecnt = 0;
1167 		sp->ttis[0].tt_gmtoff = -stdoffset;
1168 		sp->ttis[0].tt_isdst = 0;
1169 		sp->ttis[0].tt_abbrind = 0;
1170 	}
1171 	sp->charcnt = stdlen + 1;
1172 	if (dstlen != 0)
1173 		sp->charcnt += dstlen + 1;
1174 	if ((size_t) sp->charcnt > sizeof sp->chars)
1175 		return -1;
1176 	cp = sp->chars;
1177 	(void) strncpy(cp, stdname, stdlen);
1178 	cp += stdlen;
1179 	*cp++ = '\0';
1180 	if (dstlen != 0) {
1181 		(void) strncpy(cp, dstname, dstlen);
1182 		*(cp + dstlen) = '\0';
1183 	}
1184 	return 0;
1185 }
1186 
1187 static void
1188 gmtload(sp)
1189 struct state * const	sp;
1190 {
1191 	if (tzload(gmt, sp, TRUE) != 0)
1192 		(void) tzparse(gmt, sp, TRUE);
1193 }
1194 
1195 static void
1196 tzsetwall_unlocked(void)
1197 {
1198 	if (lcl_is_set < 0)
1199 		return;
1200 	lcl_is_set = -1;
1201 
1202 #ifdef ALL_STATE
1203 	if (lclptr == NULL) {
1204 		int saveerrno = errno;
1205 		lclptr = (struct state *) malloc(sizeof *lclptr);
1206 		errno = saveerrno;
1207 		if (lclptr == NULL) {
1208 			settzname();	/* all we can do */
1209 			return;
1210 		}
1211 	}
1212 #endif /* defined ALL_STATE */
1213 	if (tzload((char *) NULL, lclptr, TRUE) != 0)
1214 		gmtload(lclptr);
1215 	settzname();
1216 }
1217 
1218 #ifndef STD_INSPIRED
1219 /*
1220 ** A non-static declaration of tzsetwall in a system header file
1221 ** may cause a warning about this upcoming static declaration...
1222 */
1223 static
1224 #endif /* !defined STD_INSPIRED */
1225 void
1226 tzsetwall(void)
1227 {
1228 	rwlock_wrlock(&lcl_lock);
1229 	tzsetwall_unlocked();
1230 	rwlock_unlock(&lcl_lock);
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 tzset_unlocked(void)
1242 {
1243 	register const char *	name;
1244 	int saveerrno;
1245 
1246 	saveerrno = errno;
1247 	name = getenv("TZ");
1248 	errno = saveerrno;
1249 	if (name == NULL) {
1250 		tzsetwall_unlocked();
1251 		return;
1252 	}
1253 
1254 	if (lcl_is_set > 0 && strcmp(lcl_TZname, name) == 0)
1255 		return;
1256 	lcl_is_set = strlen(name) < sizeof lcl_TZname;
1257 	if (lcl_is_set)
1258 		(void)strlcpy(lcl_TZname, name, sizeof(lcl_TZname));
1259 
1260 #ifdef ALL_STATE
1261 	if (lclptr == NULL) {
1262 		saveerrno = errno;
1263 		lclptr = (struct state *) malloc(sizeof *lclptr);
1264 		errno = saveerrno;
1265 		if (lclptr == NULL) {
1266 			settzname();	/* all we can do */
1267 			return;
1268 		}
1269 	}
1270 #endif /* defined ALL_STATE */
1271 	if (*name == '\0') {
1272 		/*
1273 		** User wants it fast rather than right.
1274 		*/
1275 		lclptr->leapcnt = 0;		/* so, we're off a little */
1276 		lclptr->timecnt = 0;
1277 		lclptr->typecnt = 0;
1278 		lclptr->ttis[0].tt_isdst = 0;
1279 		lclptr->ttis[0].tt_gmtoff = 0;
1280 		lclptr->ttis[0].tt_abbrind = 0;
1281 		(void) strlcpy(lclptr->chars, gmt, sizeof(lclptr->chars));
1282 	} else if (tzload(name, lclptr, TRUE) != 0)
1283 		if (name[0] == ':' || tzparse(name, lclptr, FALSE) != 0)
1284 			(void) gmtload(lclptr);
1285 	settzname();
1286 }
1287 
1288 void
1289 tzset(void)
1290 {
1291 	rwlock_wrlock(&lcl_lock);
1292 	tzset_unlocked();
1293 	rwlock_unlock(&lcl_lock);
1294 }
1295 
1296 /*
1297 ** The easy way to behave "as if no library function calls" localtime
1298 ** is to not call it--so we drop its guts into "localsub", which can be
1299 ** freely called. (And no, the PANS doesn't require the above behavior--
1300 ** but it *is* desirable.)
1301 **
1302 ** The unused offset argument is for the benefit of mktime variants.
1303 */
1304 
1305 /*ARGSUSED*/
1306 static struct tm *
1307 localsub(timep, offset, tmp)
1308 const time_t * const	timep;
1309 const long		offset;
1310 struct tm * const	tmp;
1311 {
1312 	register struct state *		sp;
1313 	register const struct ttinfo *	ttisp;
1314 	register int			i;
1315 	register struct tm *		result;
1316 	const time_t			t = *timep;
1317 
1318 	sp = lclptr;
1319 #ifdef ALL_STATE
1320 	if (sp == NULL)
1321 		return gmtsub(timep, offset, tmp);
1322 #endif /* defined ALL_STATE */
1323 	if ((sp->goback && t < sp->ats[0]) ||
1324 		(sp->goahead && t > sp->ats[sp->timecnt - 1])) {
1325 			time_t			newt = t;
1326 			register time_t		seconds;
1327 			register time_t		tcycles;
1328 			register int_fast64_t	icycles;
1329 
1330 			if (t < sp->ats[0])
1331 				seconds = sp->ats[0] - t;
1332 			else	seconds = t - sp->ats[sp->timecnt - 1];
1333 			--seconds;
1334 			tcycles = seconds / YEARSPERREPEAT / AVGSECSPERYEAR;
1335 			++tcycles;
1336 			icycles = tcycles;
1337 			if (tcycles - icycles >= 1 || icycles - tcycles >= 1)
1338 				return NULL;
1339 			seconds = (time_t) icycles;
1340 			seconds *= YEARSPERREPEAT;
1341 			seconds *= AVGSECSPERYEAR;
1342 			if (t < sp->ats[0])
1343 				newt += seconds;
1344 			else	newt -= seconds;
1345 			if (newt < sp->ats[0] ||
1346 				newt > sp->ats[sp->timecnt - 1])
1347 					return NULL;	/* "cannot happen" */
1348 			result = localsub(&newt, offset, tmp);
1349 			if (result == tmp) {
1350 				register time_t	newy;
1351 
1352 				newy = tmp->tm_year;
1353 				if (t < sp->ats[0])
1354 					newy -= (time_t)icycles * YEARSPERREPEAT;
1355 				else	newy += (time_t)icycles * YEARSPERREPEAT;
1356 				tmp->tm_year = (int)newy;
1357 				if (tmp->tm_year != newy)
1358 					return NULL;
1359 			}
1360 			return result;
1361 	}
1362 	if (sp->timecnt == 0 || t < sp->ats[0]) {
1363 		i = 0;
1364 		while (sp->ttis[i].tt_isdst)
1365 			if (++i >= sp->typecnt) {
1366 				i = 0;
1367 				break;
1368 			}
1369 	} else {
1370 		register int	lo = 1;
1371 		register int	hi = sp->timecnt;
1372 
1373 		while (lo < hi) {
1374 			register int	mid = (lo + hi) / 2;
1375 
1376 			if (t < sp->ats[mid])
1377 				hi = mid;
1378 			else	lo = mid + 1;
1379 		}
1380 		i = (int) sp->types[lo - 1];
1381 	}
1382 	ttisp = &sp->ttis[i];
1383 	/*
1384 	** To get (wrong) behavior that's compatible with System V Release 2.0
1385 	** you'd replace the statement below with
1386 	**	t += ttisp->tt_gmtoff;
1387 	**	timesub(&t, 0L, sp, tmp);
1388 	*/
1389 	result = timesub(&t, ttisp->tt_gmtoff, sp, tmp);
1390 	tmp->tm_isdst = ttisp->tt_isdst;
1391 	tzname[tmp->tm_isdst] = &sp->chars[ttisp->tt_abbrind];
1392 #ifdef TM_ZONE
1393 	tmp->TM_ZONE = &sp->chars[ttisp->tt_abbrind];
1394 #endif /* defined TM_ZONE */
1395 	return result;
1396 }
1397 
1398 struct tm *
1399 localtime(timep)
1400 const time_t * const	timep;
1401 {
1402 	struct tm *result;
1403 
1404 	rwlock_wrlock(&lcl_lock);
1405 	tzset_unlocked();
1406 	result = localsub(timep, 0L, &tm);
1407 	rwlock_unlock(&lcl_lock);
1408 	return result;
1409 }
1410 
1411 /*
1412 ** Re-entrant version of localtime.
1413 */
1414 
1415 struct tm *
1416 localtime_r(timep, tmp)
1417 const time_t * const	timep;
1418 struct tm *		tmp;
1419 {
1420 	struct tm *result;
1421 
1422 	rwlock_rdlock(&lcl_lock);
1423 	tzset_unlocked();
1424 	result = localsub(timep, 0L, tmp);
1425 	rwlock_unlock(&lcl_lock);
1426 	return result;
1427 }
1428 
1429 /*
1430 ** gmtsub is to gmtime as localsub is to localtime.
1431 */
1432 
1433 static struct tm *
1434 gmtsub(timep, offset, tmp)
1435 const time_t * const	timep;
1436 const long		offset;
1437 struct tm * const	tmp;
1438 {
1439 	register struct tm *	result;
1440 #ifdef _REENTRANT
1441 	static mutex_t gmt_mutex = MUTEX_INITIALIZER;
1442 #endif
1443 
1444 	mutex_lock(&gmt_mutex);
1445 	if (!gmt_is_set) {
1446 #ifdef ALL_STATE
1447 		int saveerrno;
1448 #endif
1449 		gmt_is_set = TRUE;
1450 #ifdef ALL_STATE
1451 		saveerrno = errno;
1452 		gmtptr = (struct state *) malloc(sizeof *gmtptr);
1453 		errno = saveerrno;
1454 		if (gmtptr != NULL)
1455 #endif /* defined ALL_STATE */
1456 			gmtload(gmtptr);
1457 	}
1458 	mutex_unlock(&gmt_mutex);
1459 	result = timesub(timep, offset, gmtptr, 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 #ifdef ALL_STATE
1470 		if (gmtptr == NULL)
1471 			tmp->TM_ZONE = (__aconst char *)__UNCONST(gmt);
1472 		else	tmp->TM_ZONE = gmtptr->chars;
1473 #endif /* defined ALL_STATE */
1474 #ifndef ALL_STATE
1475 		tmp->TM_ZONE = gmtptr->chars;
1476 #endif /* State Farm */
1477 	}
1478 #endif /* defined TM_ZONE */
1479 	return result;
1480 }
1481 
1482 struct tm *
1483 gmtime(timep)
1484 const time_t * const	timep;
1485 {
1486 	return gmtsub(timep, 0L, &tm);
1487 }
1488 
1489 /*
1490 ** Re-entrant version of gmtime.
1491 */
1492 
1493 struct tm *
1494 gmtime_r(timep, tmp)
1495 const time_t * const	timep;
1496 struct tm *		tmp;
1497 {
1498 	return gmtsub(timep, 0L, tmp);
1499 }
1500 
1501 #ifdef STD_INSPIRED
1502 
1503 struct tm *
1504 offtime(timep, offset)
1505 const time_t * const	timep;
1506 const long		offset;
1507 {
1508 	return gmtsub(timep, offset, &tm);
1509 }
1510 
1511 #endif /* defined STD_INSPIRED */
1512 
1513 /*
1514 ** Return the number of leap years through the end of the given year
1515 ** where, to make the math easy, the answer for year zero is defined as zero.
1516 */
1517 
1518 static int
1519 leaps_thru_end_of(y)
1520 register const int	y;
1521 {
1522 	return (y >= 0) ? (y / 4 - y / 100 + y / 400) :
1523 		-(leaps_thru_end_of(-(y + 1)) + 1);
1524 }
1525 
1526 static struct tm *
1527 timesub(timep, offset, sp, tmp)
1528 const time_t * const			timep;
1529 const long				offset;
1530 register const struct state * const	sp;
1531 register struct tm * const		tmp;
1532 {
1533 	register const struct lsinfo *	lp;
1534 	register time_t			tdays;
1535 	register int			idays;	/* unsigned would be so 2003 */
1536 	register long			rem;
1537 	int				y;
1538 	register const int *		ip;
1539 	register long			corr;
1540 	register int			hit;
1541 	register int			i;
1542 
1543 	corr = 0;
1544 	hit = 0;
1545 #ifdef ALL_STATE
1546 	i = (sp == NULL) ? 0 : sp->leapcnt;
1547 #endif /* defined ALL_STATE */
1548 #ifndef ALL_STATE
1549 	i = sp->leapcnt;
1550 #endif /* State Farm */
1551 	while (--i >= 0) {
1552 		lp = &sp->lsis[i];
1553 		if (*timep >= lp->ls_trans) {
1554 			if (*timep == lp->ls_trans) {
1555 				hit = ((i == 0 && lp->ls_corr > 0) ||
1556 					lp->ls_corr > sp->lsis[i - 1].ls_corr);
1557 				if (hit)
1558 					while (i > 0 &&
1559 						sp->lsis[i].ls_trans ==
1560 						sp->lsis[i - 1].ls_trans + 1 &&
1561 						sp->lsis[i].ls_corr ==
1562 						sp->lsis[i - 1].ls_corr + 1) {
1563 							++hit;
1564 							--i;
1565 					}
1566 			}
1567 			corr = lp->ls_corr;
1568 			break;
1569 		}
1570 	}
1571 	y = EPOCH_YEAR;
1572 	tdays = *timep / SECSPERDAY;
1573 	rem = (long) (*timep - tdays * SECSPERDAY);
1574 	while (tdays < 0 || tdays >= year_lengths[isleap(y)]) {
1575 		int		newy;
1576 		register time_t	tdelta;
1577 		register int	idelta;
1578 		register int	leapdays;
1579 
1580 		tdelta = tdays / DAYSPERLYEAR;
1581 		idelta = (int) tdelta;
1582 		if (tdelta - idelta >= 1 || idelta - tdelta >= 1)
1583 			return NULL;
1584 		if (idelta == 0)
1585 			idelta = (tdays < 0) ? -1 : 1;
1586 		newy = y;
1587 		if (increment_overflow(&newy, idelta))
1588 			return NULL;
1589 		leapdays = leaps_thru_end_of(newy - 1) -
1590 			leaps_thru_end_of(y - 1);
1591 		tdays -= ((time_t) newy - y) * DAYSPERNYEAR;
1592 		tdays -= leapdays;
1593 		y = newy;
1594 	}
1595 	{
1596 		register long	seconds;
1597 
1598 		seconds = tdays * SECSPERDAY + 0.5;
1599 		tdays = seconds / SECSPERDAY;
1600 		rem += (long) (seconds - tdays * SECSPERDAY);
1601 	}
1602 	/*
1603 	** Given the range, we can now fearlessly cast...
1604 	*/
1605 	idays = (int) tdays;
1606 	rem += offset - corr;
1607 	while (rem < 0) {
1608 		rem += SECSPERDAY;
1609 		--idays;
1610 	}
1611 	while (rem >= SECSPERDAY) {
1612 		rem -= SECSPERDAY;
1613 		++idays;
1614 	}
1615 	while (idays < 0) {
1616 		if (increment_overflow(&y, -1))
1617 			return NULL;
1618 		idays += year_lengths[isleap(y)];
1619 	}
1620 	while (idays >= year_lengths[isleap(y)]) {
1621 		idays -= year_lengths[isleap(y)];
1622 		if (increment_overflow(&y, 1))
1623 			return NULL;
1624 	}
1625 	tmp->tm_year = y;
1626 	if (increment_overflow(&tmp->tm_year, -TM_YEAR_BASE))
1627 		return NULL;
1628 	tmp->tm_yday = idays;
1629 	/*
1630 	** The "extra" mods below avoid overflow problems.
1631 	*/
1632 	tmp->tm_wday = EPOCH_WDAY +
1633 		((y - EPOCH_YEAR) % DAYSPERWEEK) *
1634 		(DAYSPERNYEAR % DAYSPERWEEK) +
1635 		leaps_thru_end_of(y - 1) -
1636 		leaps_thru_end_of(EPOCH_YEAR - 1) +
1637 		idays;
1638 	tmp->tm_wday %= DAYSPERWEEK;
1639 	if (tmp->tm_wday < 0)
1640 		tmp->tm_wday += DAYSPERWEEK;
1641 	tmp->tm_hour = (int) (rem / SECSPERHOUR);
1642 	rem %= SECSPERHOUR;
1643 	tmp->tm_min = (int) (rem / SECSPERMIN);
1644 	/*
1645 	** A positive leap second requires a special
1646 	** representation. This uses "... ??:59:60" et seq.
1647 	*/
1648 	tmp->tm_sec = (int) (rem % SECSPERMIN) + hit;
1649 	ip = mon_lengths[isleap(y)];
1650 	for (tmp->tm_mon = 0; idays >= ip[tmp->tm_mon]; ++(tmp->tm_mon))
1651 		idays -= ip[tmp->tm_mon];
1652 	tmp->tm_mday = (int) (idays + 1);
1653 	tmp->tm_isdst = 0;
1654 #ifdef TM_GMTOFF
1655 	tmp->TM_GMTOFF = offset;
1656 #endif /* defined TM_GMTOFF */
1657 	return tmp;
1658 }
1659 
1660 char *
1661 ctime(timep)
1662 const time_t * const	timep;
1663 {
1664 /*
1665 ** Section 4.12.3.2 of X3.159-1989 requires that
1666 **	The ctime function converts the calendar time pointed to by timer
1667 **	to local time in the form of a string. It is equivalent to
1668 **		asctime(localtime(timer))
1669 */
1670 	return asctime(localtime(timep));
1671 }
1672 
1673 char *
1674 ctime_r(timep, buf)
1675 const time_t * const	timep;
1676 char *			buf;
1677 {
1678 	struct tm	mytm;
1679 
1680 	return asctime_r(localtime_r(timep, &mytm), buf);
1681 }
1682 
1683 /*
1684 ** Adapted from code provided by Robert Elz, who writes:
1685 **	The "best" way to do mktime I think is based on an idea of Bob
1686 **	Kridle's (so its said...) from a long time ago.
1687 **	It does a binary search of the time_t space. Since time_t's are
1688 **	just 32 bits, its a max of 32 iterations (even at 64 bits it
1689 **	would still be very reasonable).
1690 */
1691 
1692 #ifndef WRONG
1693 #define WRONG	(-1)
1694 #endif /* !defined WRONG */
1695 
1696 /*
1697 ** Simplified normalize logic courtesy Paul Eggert.
1698 */
1699 
1700 static int
1701 increment_overflow(number, delta)
1702 int *	number;
1703 int	delta;
1704 {
1705 	int	number0;
1706 
1707 	number0 = *number;
1708 	*number += delta;
1709 	return (*number < number0) != (delta < 0);
1710 }
1711 
1712 static int
1713 long_increment_overflow(number, delta)
1714 long *	number;
1715 int	delta;
1716 {
1717 	long	number0;
1718 
1719 	number0 = *number;
1720 	*number += delta;
1721 	return (*number < number0) != (delta < 0);
1722 }
1723 
1724 static int
1725 normalize_overflow(tensptr, unitsptr, base)
1726 int * const	tensptr;
1727 int * const	unitsptr;
1728 const int	base;
1729 {
1730 	register int	tensdelta;
1731 
1732 	tensdelta = (*unitsptr >= 0) ?
1733 		(*unitsptr / base) :
1734 		(-1 - (-1 - *unitsptr) / base);
1735 	*unitsptr -= tensdelta * base;
1736 	return increment_overflow(tensptr, tensdelta);
1737 }
1738 
1739 static int
1740 long_normalize_overflow(tensptr, unitsptr, base)
1741 long * const	tensptr;
1742 int * const	unitsptr;
1743 const int	base;
1744 {
1745 	register int	tensdelta;
1746 
1747 	tensdelta = (*unitsptr >= 0) ?
1748 		(*unitsptr / base) :
1749 		(-1 - (-1 - *unitsptr) / base);
1750 	*unitsptr -= tensdelta * base;
1751 	return long_increment_overflow(tensptr, tensdelta);
1752 }
1753 
1754 static int
1755 tmcomp(atmp, btmp)
1756 register const struct tm * const atmp;
1757 register const struct tm * const btmp;
1758 {
1759 	register int	result;
1760 
1761 	if ((result = (atmp->tm_year - btmp->tm_year)) == 0 &&
1762 		(result = (atmp->tm_mon - btmp->tm_mon)) == 0 &&
1763 		(result = (atmp->tm_mday - btmp->tm_mday)) == 0 &&
1764 		(result = (atmp->tm_hour - btmp->tm_hour)) == 0 &&
1765 		(result = (atmp->tm_min - btmp->tm_min)) == 0)
1766 			result = atmp->tm_sec - btmp->tm_sec;
1767 	return result;
1768 }
1769 
1770 static time_t
1771 time2sub(tmp, funcp, offset, okayp, do_norm_secs)
1772 struct tm * const	tmp;
1773 struct tm * (* const	funcp)(const time_t*, long, struct tm*);
1774 const long		offset;
1775 int * const		okayp;
1776 const int		do_norm_secs;
1777 {
1778 	register const struct state *	sp;
1779 	register int			dir;
1780 	register int			i, j;
1781 	register int			saved_seconds;
1782 	register long			li;
1783 	register time_t			lo;
1784 	register time_t			hi;
1785 	long				y;
1786 	time_t				newt;
1787 	time_t				t;
1788 	struct tm			yourtm, mytm;
1789 
1790 	*okayp = FALSE;
1791 	yourtm = *tmp;
1792 	if (do_norm_secs) {
1793 		if (normalize_overflow(&yourtm.tm_min, &yourtm.tm_sec,
1794 			SECSPERMIN))
1795 				return WRONG;
1796 	}
1797 	if (normalize_overflow(&yourtm.tm_hour, &yourtm.tm_min, MINSPERHOUR))
1798 		return WRONG;
1799 	if (normalize_overflow(&yourtm.tm_mday, &yourtm.tm_hour, HOURSPERDAY))
1800 		return WRONG;
1801 	y = yourtm.tm_year;
1802 	if (long_normalize_overflow(&y, &yourtm.tm_mon, MONSPERYEAR))
1803 		return WRONG;
1804 	/*
1805 	** Turn y into an actual year number for now.
1806 	** It is converted back to an offset from TM_YEAR_BASE later.
1807 	*/
1808 	if (long_increment_overflow(&y, TM_YEAR_BASE))
1809 		return WRONG;
1810 	while (yourtm.tm_mday <= 0) {
1811 		if (long_increment_overflow(&y, -1))
1812 			return WRONG;
1813 		li = y + (1 < yourtm.tm_mon);
1814 		yourtm.tm_mday += year_lengths[isleap(li)];
1815 	}
1816 	while (yourtm.tm_mday > DAYSPERLYEAR) {
1817 		li = y + (1 < yourtm.tm_mon);
1818 		yourtm.tm_mday -= year_lengths[isleap(li)];
1819 		if (long_increment_overflow(&y, 1))
1820 			return WRONG;
1821 	}
1822 	for ( ; ; ) {
1823 		i = mon_lengths[isleap(y)][yourtm.tm_mon];
1824 		if (yourtm.tm_mday <= i)
1825 			break;
1826 		yourtm.tm_mday -= i;
1827 		if (++yourtm.tm_mon >= MONSPERYEAR) {
1828 			yourtm.tm_mon = 0;
1829 			if (long_increment_overflow(&y, 1))
1830 				return WRONG;
1831 		}
1832 	}
1833 	if (long_increment_overflow(&y, -TM_YEAR_BASE))
1834 		return WRONG;
1835 	yourtm.tm_year = y;
1836 	if (yourtm.tm_year != y)
1837 		return WRONG;
1838 	if (yourtm.tm_sec >= 0 && yourtm.tm_sec < SECSPERMIN)
1839 		saved_seconds = 0;
1840 	else if (y + TM_YEAR_BASE < EPOCH_YEAR) {
1841 		/*
1842 		** We can't set tm_sec to 0, because that might push the
1843 		** time below the minimum representable time.
1844 		** Set tm_sec to 59 instead.
1845 		** This assumes that the minimum representable time is
1846 		** not in the same minute that a leap second was deleted from,
1847 		** which is a safer assumption than using 58 would be.
1848 		*/
1849 		if (increment_overflow(&yourtm.tm_sec, 1 - SECSPERMIN))
1850 			return WRONG;
1851 		saved_seconds = yourtm.tm_sec;
1852 		yourtm.tm_sec = SECSPERMIN - 1;
1853 	} else {
1854 		saved_seconds = yourtm.tm_sec;
1855 		yourtm.tm_sec = 0;
1856 	}
1857 	/*
1858 	** Do a binary search (this works whatever time_t's type is).
1859 	*/
1860 /* LINTED constant */
1861 	if (!TYPE_SIGNED(time_t)) {
1862 		lo = 0;
1863 		hi = lo - 1;
1864 /* LINTED constant */
1865 	} else if (!TYPE_INTEGRAL(time_t)) {
1866 /* CONSTCOND */
1867 		if (sizeof(time_t) > sizeof(float))
1868 /* LINTED assumed double */
1869 			hi = (time_t) DBL_MAX;
1870 /* LINTED assumed float */
1871 		else	hi = (time_t) FLT_MAX;
1872 		lo = -hi;
1873 	} else {
1874 		lo = 1;
1875 		for (i = 0; i < (int) TYPE_BIT(time_t) - 1; ++i)
1876 			lo *= 2;
1877 		hi = -(lo + 1);
1878 	}
1879 	for ( ; ; ) {
1880 		t = lo / 2 + hi / 2;
1881 		if (t < lo)
1882 			t = lo;
1883 		else if (t > hi)
1884 			t = hi;
1885 		if ((*funcp)(&t, offset, &mytm) == NULL) {
1886 			/*
1887 			** Assume that t is too extreme to be represented in
1888 			** a struct tm; arrange things so that it is less
1889 			** extreme on the next pass.
1890 			*/
1891 			dir = (t > 0) ? 1 : -1;
1892 		} else	dir = tmcomp(&mytm, &yourtm);
1893 		if (dir != 0) {
1894 			if (t == lo) {
1895 				++t;
1896 				if (t <= lo)
1897 					return WRONG;
1898 				++lo;
1899 			} else if (t == hi) {
1900 				--t;
1901 				if (t >= hi)
1902 					return WRONG;
1903 				--hi;
1904 			}
1905 			if (lo > hi)
1906 				return WRONG;
1907 			if (dir > 0)
1908 				hi = t;
1909 			else	lo = t;
1910 			continue;
1911 		}
1912 		if (yourtm.tm_isdst < 0 || mytm.tm_isdst == yourtm.tm_isdst)
1913 			break;
1914 		/*
1915 		** Right time, wrong type.
1916 		** Hunt for right time, right type.
1917 		** It's okay to guess wrong since the guess
1918 		** gets checked.
1919 		*/
1920 		sp = (const struct state *)
1921 			((funcp == localsub) ? lclptr : gmtptr);
1922 #ifdef ALL_STATE
1923 		if (sp == NULL)
1924 			return WRONG;
1925 #endif /* defined ALL_STATE */
1926 		for (i = sp->typecnt - 1; i >= 0; --i) {
1927 			if (sp->ttis[i].tt_isdst != yourtm.tm_isdst)
1928 				continue;
1929 			for (j = sp->typecnt - 1; j >= 0; --j) {
1930 				if (sp->ttis[j].tt_isdst == yourtm.tm_isdst)
1931 					continue;
1932 				newt = t + sp->ttis[j].tt_gmtoff -
1933 					sp->ttis[i].tt_gmtoff;
1934 				if ((*funcp)(&newt, offset, &mytm) == NULL)
1935 					continue;
1936 				if (tmcomp(&mytm, &yourtm) != 0)
1937 					continue;
1938 				if (mytm.tm_isdst != yourtm.tm_isdst)
1939 					continue;
1940 				/*
1941 				** We have a match.
1942 				*/
1943 				t = newt;
1944 				goto label;
1945 			}
1946 		}
1947 		return WRONG;
1948 	}
1949 label:
1950 	newt = t + saved_seconds;
1951 	if ((newt < t) != (saved_seconds < 0))
1952 		return WRONG;
1953 	t = newt;
1954 	if ((*funcp)(&t, offset, tmp))
1955 		*okayp = TRUE;
1956 	return t;
1957 }
1958 
1959 static time_t
1960 time2(tmp, funcp, offset, okayp)
1961 struct tm * const	tmp;
1962 struct tm * (* const	funcp)(const time_t*, long, struct tm*);
1963 const long		offset;
1964 int * const		okayp;
1965 {
1966 	time_t	t;
1967 
1968 	/*
1969 	** First try without normalization of seconds
1970 	** (in case tm_sec contains a value associated with a leap second).
1971 	** If that fails, try with normalization of seconds.
1972 	*/
1973 	t = time2sub(tmp, funcp, offset, okayp, FALSE);
1974 	return *okayp ? t : time2sub(tmp, funcp, offset, okayp, TRUE);
1975 }
1976 
1977 static time_t
1978 time1(tmp, funcp, offset)
1979 struct tm * const	tmp;
1980 struct tm * (* const	funcp)(const time_t *, long, struct tm *);
1981 const long		offset;
1982 {
1983 	register time_t			t;
1984 	register const struct state *	sp;
1985 	register int			samei, otheri;
1986 	register int			sameind, otherind;
1987 	register int			i;
1988 	register int			nseen;
1989 	int				seen[TZ_MAX_TYPES];
1990 	int				types[TZ_MAX_TYPES];
1991 	int				okay;
1992 
1993 	if (tmp->tm_isdst > 1)
1994 		tmp->tm_isdst = 1;
1995 	t = time2(tmp, funcp, offset, &okay);
1996 #ifdef PCTS
1997 	/*
1998 	** PCTS code courtesy Grant Sullivan.
1999 	*/
2000 	if (okay)
2001 		return t;
2002 	if (tmp->tm_isdst < 0)
2003 		tmp->tm_isdst = 0;	/* reset to std and try again */
2004 #endif /* defined PCTS */
2005 #ifndef PCTS
2006 	if (okay || tmp->tm_isdst < 0)
2007 		return t;
2008 #endif /* !defined PCTS */
2009 	/*
2010 	** We're supposed to assume that somebody took a time of one type
2011 	** and did some math on it that yielded a "struct tm" that's bad.
2012 	** We try to divine the type they started from and adjust to the
2013 	** type they need.
2014 	*/
2015 	sp = (const struct state *) ((funcp == localsub) ?  lclptr : gmtptr);
2016 #ifdef ALL_STATE
2017 	if (sp == NULL)
2018 		return WRONG;
2019 #endif /* defined ALL_STATE */
2020 	for (i = 0; i < sp->typecnt; ++i)
2021 		seen[i] = FALSE;
2022 	nseen = 0;
2023 	for (i = sp->timecnt - 1; i >= 0; --i)
2024 		if (!seen[sp->types[i]]) {
2025 			seen[sp->types[i]] = TRUE;
2026 			types[nseen++] = sp->types[i];
2027 		}
2028 	for (sameind = 0; sameind < nseen; ++sameind) {
2029 		samei = types[sameind];
2030 		if (sp->ttis[samei].tt_isdst != tmp->tm_isdst)
2031 			continue;
2032 		for (otherind = 0; otherind < nseen; ++otherind) {
2033 			otheri = types[otherind];
2034 			if (sp->ttis[otheri].tt_isdst == tmp->tm_isdst)
2035 				continue;
2036 			tmp->tm_sec += (int)(sp->ttis[otheri].tt_gmtoff -
2037 					sp->ttis[samei].tt_gmtoff);
2038 			tmp->tm_isdst = !tmp->tm_isdst;
2039 			t = time2(tmp, funcp, offset, &okay);
2040 			if (okay)
2041 				return t;
2042 			tmp->tm_sec -= (int)(sp->ttis[otheri].tt_gmtoff -
2043 					sp->ttis[samei].tt_gmtoff);
2044 			tmp->tm_isdst = !tmp->tm_isdst;
2045 		}
2046 	}
2047 	return WRONG;
2048 }
2049 
2050 time_t
2051 mktime(tmp)
2052 struct tm * const	tmp;
2053 {
2054 	time_t result;
2055 
2056 	rwlock_wrlock(&lcl_lock);
2057 	tzset_unlocked();
2058 	result = time1(tmp, localsub, 0L);
2059 	rwlock_unlock(&lcl_lock);
2060 	return (result);
2061 }
2062 
2063 #ifdef STD_INSPIRED
2064 
2065 time_t
2066 timelocal(tmp)
2067 struct tm * const	tmp;
2068 {
2069 	tmp->tm_isdst = -1;	/* in case it wasn't initialized */
2070 	return mktime(tmp);
2071 }
2072 
2073 time_t
2074 timegm(tmp)
2075 struct tm * const	tmp;
2076 {
2077 	tmp->tm_isdst = 0;
2078 	return time1(tmp, gmtsub, 0L);
2079 }
2080 
2081 time_t
2082 timeoff(tmp, offset)
2083 struct tm * const	tmp;
2084 const long		offset;
2085 {
2086 	tmp->tm_isdst = 0;
2087 	return time1(tmp, gmtsub, offset);
2088 }
2089 
2090 #endif /* defined STD_INSPIRED */
2091 
2092 #ifdef CMUCS
2093 
2094 /*
2095 ** The following is supplied for compatibility with
2096 ** previous versions of the CMUCS runtime library.
2097 */
2098 
2099 long
2100 gtime(tmp)
2101 struct tm * const	tmp;
2102 {
2103 	const time_t	t = mktime(tmp);
2104 
2105 	if (t == WRONG)
2106 		return -1;
2107 	return t;
2108 }
2109 
2110 #endif /* defined CMUCS */
2111 
2112 /*
2113 ** XXX--is the below the right way to conditionalize??
2114 */
2115 
2116 #ifdef STD_INSPIRED
2117 
2118 /*
2119 ** IEEE Std 1003.1-1988 (POSIX) legislates that 536457599
2120 ** shall correspond to "Wed Dec 31 23:59:59 UTC 1986", which
2121 ** is not the case if we are accounting for leap seconds.
2122 ** So, we provide the following conversion routines for use
2123 ** when exchanging timestamps with POSIX conforming systems.
2124 */
2125 
2126 static long
2127 leapcorr(timep)
2128 time_t *	timep;
2129 {
2130 	register struct state *		sp;
2131 	register struct lsinfo *	lp;
2132 	register int			i;
2133 
2134 	sp = lclptr;
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(t)
2146 time_t	t;
2147 {
2148 	time_t result;
2149 
2150 	rwlock_wrlock(&lcl_lock);
2151 	tzset_unlocked();
2152 	result = t - leapcorr(&t);
2153 	rwlock_unlock(&lcl_lock);
2154 	return (result);
2155 }
2156 
2157 time_t
2158 posix2time(t)
2159 time_t	t;
2160 {
2161 	time_t	x;
2162 	time_t	y;
2163 
2164 	rwlock_wrlock(&lcl_lock);
2165 	tzset_unlocked();
2166 	/*
2167 	** For a positive leap second hit, the result
2168 	** is not unique. For a negative leap second
2169 	** hit, the corresponding time doesn't exist,
2170 	** so we return an adjacent second.
2171 	*/
2172 	x = t + leapcorr(&t);
2173 	y = x - leapcorr(&x);
2174 	if (y < t) {
2175 		do {
2176 			x++;
2177 			y = x - leapcorr(&x);
2178 		} while (y < t);
2179 		if (t != y) {
2180 			rwlock_unlock(&lcl_lock);
2181 			return x - 1;
2182 		}
2183 	} else if (y > t) {
2184 		do {
2185 			--x;
2186 			y = x - leapcorr(&x);
2187 		} while (y > t);
2188 		if (t != y) {
2189 			rwlock_unlock(&lcl_lock);
2190 			return x + 1;
2191 		}
2192 	}
2193 	rwlock_unlock(&lcl_lock);
2194 	return x;
2195 }
2196 
2197 #endif /* defined STD_INSPIRED */
2198