xref: /netbsd-src/lib/libc/time/localtime.c (revision b1c86f5f087524e68db12794ee9c3e3da1ab17a0)
1 /*	$NetBSD: localtime.c,v 1.48 2010/03/23 20:28:58 drochner 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 1.48 2010/03/23 20:28:58 drochner 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 #endif
34 
35 #include "float.h"	/* for FLT_MAX and DBL_MAX */
36 
37 #ifndef TZ_ABBR_MAX_LEN
38 #define TZ_ABBR_MAX_LEN	16
39 #endif /* !defined TZ_ABBR_MAX_LEN */
40 
41 #ifndef TZ_ABBR_CHAR_SET
42 #define TZ_ABBR_CHAR_SET \
43 	"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789 :+-._"
44 #endif /* !defined TZ_ABBR_CHAR_SET */
45 
46 #ifndef TZ_ABBR_ERR_CHAR
47 #define TZ_ABBR_ERR_CHAR	'_'
48 #endif /* !defined TZ_ABBR_ERR_CHAR */
49 
50 /*
51 ** SunOS 4.1.1 headers lack O_BINARY.
52 */
53 
54 #ifdef O_BINARY
55 #define OPEN_MODE	(O_RDONLY | O_BINARY)
56 #endif /* defined O_BINARY */
57 #ifndef O_BINARY
58 #define OPEN_MODE	O_RDONLY
59 #endif /* !defined O_BINARY */
60 
61 #ifndef WILDABBR
62 /*
63 ** Someone might make incorrect use of a time zone abbreviation:
64 **	1.	They might reference tzname[0] before calling tzset (explicitly
65 **		or implicitly).
66 **	2.	They might reference tzname[1] before calling tzset (explicitly
67 **		or implicitly).
68 **	3.	They might reference tzname[1] after setting to a time zone
69 **		in which Daylight Saving Time is never observed.
70 **	4.	They might reference tzname[0] after setting to a time zone
71 **		in which Standard Time is never observed.
72 **	5.	They might reference tm.TM_ZONE after calling offtime.
73 ** What's best to do in the above cases is open to debate;
74 ** for now, we just set things up so that in any of the five cases
75 ** WILDABBR is used. Another possibility: initialize tzname[0] to the
76 ** string "tzname[0] used before set", and similarly for the other cases.
77 ** And another: initialize tzname[0] to "ERA", with an explanation in the
78 ** manual page of what this "time zone abbreviation" means (doing this so
79 ** that tzname[0] has the "normal" length of three characters).
80 */
81 #define WILDABBR	"   "
82 #endif /* !defined WILDABBR */
83 
84 static const char	wildabbr[] = WILDABBR;
85 
86 static const char	gmt[] = "GMT";
87 
88 /*
89 ** The DST rules to use if TZ has no rules and we can't load TZDEFRULES.
90 ** We default to US rules as of 1999-08-17.
91 ** POSIX 1003.1 section 8.1.1 says that the default DST rules are
92 ** implementation dependent; for historical reasons, US rules are a
93 ** common default.
94 */
95 #ifndef TZDEFRULESTRING
96 #define TZDEFRULESTRING ",M4.1.0,M10.5.0"
97 #endif /* !defined TZDEFDST */
98 
99 struct ttinfo {				/* time type information */
100 	long		tt_gmtoff;	/* UTC offset in seconds */
101 	int		tt_isdst;	/* used to set tm_isdst */
102 	int		tt_abbrind;	/* abbreviation list index */
103 	int		tt_ttisstd;	/* TRUE if transition is std time */
104 	int		tt_ttisgmt;	/* TRUE if transition is UTC */
105 };
106 
107 struct lsinfo {				/* leap second information */
108 	time_t		ls_trans;	/* transition time */
109 	long		ls_corr;	/* correction to apply */
110 };
111 
112 #define BIGGEST(a, b)	(((a) > (b)) ? (a) : (b))
113 
114 #ifdef TZNAME_MAX
115 #define MY_TZNAME_MAX	TZNAME_MAX
116 #endif /* defined TZNAME_MAX */
117 #ifndef TZNAME_MAX
118 #define MY_TZNAME_MAX	255
119 #endif /* !defined TZNAME_MAX */
120 
121 struct state {
122 	int		leapcnt;
123 	int		timecnt;
124 	int		typecnt;
125 	int		charcnt;
126 	int		goback;
127 	int		goahead;
128 	time_t		ats[TZ_MAX_TIMES];
129 	unsigned char	types[TZ_MAX_TIMES];
130 	struct ttinfo	ttis[TZ_MAX_TYPES];
131 	char		chars[/*CONSTCOND*/BIGGEST(BIGGEST(TZ_MAX_CHARS + 1, sizeof gmt),
132 				(2 * (MY_TZNAME_MAX + 1)))];
133 	struct lsinfo	lsis[TZ_MAX_LEAPS];
134 };
135 
136 struct rule {
137 	int		r_type;		/* type of rule--see below */
138 	int		r_day;		/* day number of rule */
139 	int		r_week;		/* week number of rule */
140 	int		r_mon;		/* month number of rule */
141 	long		r_time;		/* transition time of rule */
142 };
143 
144 #define JULIAN_DAY		0	/* Jn - Julian day */
145 #define DAY_OF_YEAR		1	/* n - day of year */
146 #define MONTH_NTH_DAY_OF_WEEK	2	/* Mm.n.d - month, week, day of week */
147 
148 /*
149 ** Prototypes for static functions.
150 */
151 
152 static long		detzcode(const char * codep);
153 static time_t		detzcode64(const char * codep);
154 static int		differ_by_repeat(time_t t1, time_t t0);
155 static const char *	getzname(const char * strp);
156 static const char *	getqzname(const char * strp, const int delim);
157 static const char *	getnum(const char * strp, int * nump, int min,
158 				int max);
159 static const char *	getsecs(const char * strp, long * secsp);
160 static const char *	getoffset(const char * strp, long * offsetp);
161 static const char *	getrule(const char * strp, struct rule * rulep);
162 static void		gmtload(struct state * sp);
163 static struct tm *	gmtsub(const time_t * timep, long offset,
164 				struct tm * tmp);
165 static struct tm *	localsub(const time_t * timep, long offset,
166 				struct tm * tmp);
167 static int		increment_overflow(int * number, int delta);
168 static int		leaps_thru_end_of(int y);
169 static int		long_increment_overflow(long * number, int delta);
170 static int		long_normalize_overflow(long * tensptr,
171 				int * unitsptr, int base);
172 static int		normalize_overflow(int * tensptr, int * unitsptr,
173 				int base);
174 static void		settzname(void);
175 static time_t		time1(struct tm * tmp,
176 				struct tm * (*funcp)(const time_t *,
177 				long, struct tm *),
178 				long offset);
179 static time_t		time2(struct tm *tmp,
180 				struct tm * (*funcp)(const time_t *,
181 				long, struct tm*),
182 				long offset, int * okayp);
183 static time_t		time2sub(struct tm *tmp,
184 				struct tm * (*funcp)(const time_t *,
185 				long, struct tm*),
186 				long offset, int * okayp, int do_norm_secs);
187 static struct tm *	timesub(const time_t * timep, long offset,
188 				const struct state * sp, struct tm * tmp);
189 static int		tmcomp(const struct tm * atmp,
190 				const struct tm * btmp);
191 static time_t		transtime(time_t janfirst, int year,
192 				const struct rule * rulep, long offset);
193 static int		typesequiv(const struct state * sp, int a, int b);
194 static int		tzload(const char * name, struct state * sp,
195 				int doextend);
196 static int		tzparse(const char * name, struct state * sp,
197 				int lastditch);
198 static void		tzset_unlocked(void);
199 static void		tzsetwall_unlocked(void);
200 static long		leapcorr(time_t * timep);
201 
202 #ifdef ALL_STATE
203 static struct state *	lclptr;
204 static struct state *	gmtptr;
205 #endif /* defined ALL_STATE */
206 
207 #ifndef ALL_STATE
208 static struct state	lclmem;
209 static struct state	gmtmem;
210 #define lclptr		(&lclmem)
211 #define gmtptr		(&gmtmem)
212 #endif /* State Farm */
213 
214 #ifndef TZ_STRLEN_MAX
215 #define TZ_STRLEN_MAX 255
216 #endif /* !defined TZ_STRLEN_MAX */
217 
218 static char		lcl_TZname[TZ_STRLEN_MAX + 1];
219 static int		lcl_is_set;
220 static int		gmt_is_set;
221 
222 #if !defined(__LIBC12_SOURCE__)
223 
224 __aconst char *		tzname[2] = {
225 	(__aconst char *)__UNCONST(wildabbr),
226 	(__aconst char *)__UNCONST(wildabbr)
227 };
228 
229 #else
230 
231 extern __aconst char *	tzname[2];
232 
233 #endif
234 
235 #ifdef _REENTRANT
236 static rwlock_t lcl_lock = RWLOCK_INITIALIZER;
237 #endif
238 
239 /*
240 ** Section 4.12.3 of X3.159-1989 requires that
241 **	Except for the strftime function, these functions [asctime,
242 **	ctime, gmtime, localtime] return values in one of two static
243 **	objects: a broken-down time structure and an array of char.
244 ** Thanks to Paul Eggert for noting this.
245 */
246 
247 static struct tm	tm;
248 
249 #ifdef USG_COMPAT
250 #if !defined(__LIBC12_SOURCE__)
251 long 			timezone = 0;
252 int			daylight = 0;
253 #else
254 extern int		daylight;
255 extern long		timezone __RENAME(__timezone13);
256 #endif
257 #endif /* defined USG_COMPAT */
258 
259 #ifdef ALTZONE
260 time_t			altzone = 0;
261 #endif /* defined ALTZONE */
262 
263 static long
264 detzcode(codep)
265 const char * const	codep;
266 {
267 	register long	result;
268 	register int	i;
269 
270 	result = (codep[0] & 0x80) ? ~0L : 0;
271 	for (i = 0; i < 4; ++i)
272 		result = (result << 8) | (codep[i] & 0xff);
273 	return result;
274 }
275 
276 static time_t
277 detzcode64(codep)
278 const char * const	codep;
279 {
280 	register time_t	result;
281 	register int	i;
282 
283 	result = (codep[0] & 0x80) ? -1 : 0;
284 	for (i = 0; i < 8; ++i)
285 		result = result * 256 + (codep[i] & 0xff);
286 	return result;
287 }
288 
289 static void
290 settzname(void)
291 {
292 	register struct state * const	sp = lclptr;
293 	register int			i;
294 
295 	tzname[0] = (__aconst char *)__UNCONST(wildabbr);
296 	tzname[1] = (__aconst char *)__UNCONST(wildabbr);
297 #ifdef USG_COMPAT
298 	daylight = 0;
299 	timezone = 0;
300 #endif /* defined USG_COMPAT */
301 #ifdef ALTZONE
302 	altzone = 0;
303 #endif /* defined ALTZONE */
304 #ifdef ALL_STATE
305 	if (sp == NULL) {
306 		tzname[0] = tzname[1] = (__aconst char *)__UNCONST(gmt);
307 		return;
308 	}
309 #endif /* defined ALL_STATE */
310 	for (i = 0; i < sp->typecnt; ++i) {
311 		register const struct ttinfo * const	ttisp = &sp->ttis[i];
312 
313 		tzname[ttisp->tt_isdst] =
314 			&sp->chars[ttisp->tt_abbrind];
315 #ifdef USG_COMPAT
316 		if (ttisp->tt_isdst)
317 			daylight = 1;
318 		if (i == 0 || !ttisp->tt_isdst)
319 			timezone = -(ttisp->tt_gmtoff);
320 #endif /* defined USG_COMPAT */
321 #ifdef ALTZONE
322 		if (i == 0 || ttisp->tt_isdst)
323 			altzone = -(ttisp->tt_gmtoff);
324 #endif /* defined ALTZONE */
325 	}
326 	/*
327 	** And to get the latest zone names into tzname. . .
328 	*/
329 	for (i = 0; i < sp->timecnt; ++i) {
330 		register const struct ttinfo * const	ttisp =
331 							&sp->ttis[
332 								sp->types[i]];
333 
334 		tzname[ttisp->tt_isdst] =
335 			&sp->chars[ttisp->tt_abbrind];
336 	}
337 	/*
338 	** Finally, scrub the abbreviations.
339 	** First, replace bogus characters.
340 	*/
341 	for (i = 0; i < sp->charcnt; ++i)
342 		if (strchr(TZ_ABBR_CHAR_SET, sp->chars[i]) == NULL)
343 			sp->chars[i] = TZ_ABBR_ERR_CHAR;
344 	/*
345 	** Second, truncate long abbreviations.
346 	*/
347 	for (i = 0; i < sp->typecnt; ++i) {
348 		register const struct ttinfo * const	ttisp = &sp->ttis[i];
349 		register char *				cp = &sp->chars[ttisp->tt_abbrind];
350 
351 		if (strlen(cp) > TZ_ABBR_MAX_LEN &&
352 			strcmp(cp, GRANDPARENTED) != 0)
353 				*(cp + TZ_ABBR_MAX_LEN) = '\0';
354 	}
355 }
356 
357 static int
358 differ_by_repeat(t1, t0)
359 const time_t	t1;
360 const time_t	t0;
361 {
362 /* CONSTCOND */
363 	if (TYPE_INTEGRAL(time_t) &&
364 		TYPE_BIT(time_t) - TYPE_SIGNED(time_t) < SECSPERREPEAT_BITS)
365 			return 0;
366 	return (int_fast64_t)t1 - (int_fast64_t)t0 == SECSPERREPEAT;
367 }
368 
369 static int
370 tzload(name, sp, doextend)
371 register const char *		name;
372 register struct state * const	sp;
373 register const int		doextend;
374 {
375 	register const char *		p;
376 	register int			i;
377 	register int			fid;
378 	register int			stored;
379 	register int			nread;
380 	union {
381 		struct tzhead	tzhead;
382 		char		buf[2 * sizeof(struct tzhead) +
383 					2 * sizeof *sp +
384 					4 * TZ_MAX_TIMES];
385 	} u;
386 
387 	sp->goback = sp->goahead = FALSE;
388 	if (name == NULL && (name = TZDEFAULT) == NULL)
389 		return -1;
390 	{
391 		register int	doaccess;
392 		/*
393 		** Section 4.9.1 of the C standard says that
394 		** "FILENAME_MAX expands to an integral constant expression
395 		** that is the size needed for an array of char large enough
396 		** to hold the longest file name string that the implementation
397 		** guarantees can be opened."
398 		*/
399 		char		fullname[FILENAME_MAX + 1];
400 
401 		if (name[0] == ':')
402 			++name;
403 		doaccess = name[0] == '/';
404 		if (!doaccess) {
405 			if ((p = TZDIR) == NULL)
406 				return -1;
407 			if ((strlen(p) + strlen(name) + 1) >= sizeof fullname)
408 				return -1;
409 			(void) strcpy(fullname, p);	/* XXX strcpy is safe */
410 			(void) strcat(fullname, "/");	/* XXX strcat is safe */
411 			(void) strcat(fullname, name);	/* XXX strcat is safe */
412 			/*
413 			** Set doaccess if '.' (as in "../") shows up in name.
414 			*/
415 			if (strchr(name, '.') != NULL)
416 				doaccess = TRUE;
417 			name = fullname;
418 		}
419 		if (doaccess && access(name, R_OK) != 0)
420 			return -1;
421 		/*
422 		 * XXX potential security problem here if user of a set-id
423 		 * program has set TZ (which is passed in as name) here,
424 		 * and uses a race condition trick to defeat the access(2)
425 		 * above.
426 		 */
427 		if ((fid = open(name, OPEN_MODE)) == -1)
428 			return -1;
429 	}
430 	nread = read(fid, u.buf, sizeof u.buf);
431 	if (close(fid) < 0 || nread <= 0)
432 		return -1;
433 	for (stored = 4; stored <= 8; stored *= 2) {
434 		int		ttisstdcnt;
435 		int		ttisgmtcnt;
436 
437 		ttisstdcnt = (int) detzcode(u.tzhead.tzh_ttisstdcnt);
438 		ttisgmtcnt = (int) detzcode(u.tzhead.tzh_ttisgmtcnt);
439 		sp->leapcnt = (int) detzcode(u.tzhead.tzh_leapcnt);
440 		sp->timecnt = (int) detzcode(u.tzhead.tzh_timecnt);
441 		sp->typecnt = (int) detzcode(u.tzhead.tzh_typecnt);
442 		sp->charcnt = (int) detzcode(u.tzhead.tzh_charcnt);
443 		p = u.tzhead.tzh_charcnt + sizeof u.tzhead.tzh_charcnt;
444 		if (sp->leapcnt < 0 || sp->leapcnt > TZ_MAX_LEAPS ||
445 			sp->typecnt <= 0 || sp->typecnt > TZ_MAX_TYPES ||
446 			sp->timecnt < 0 || sp->timecnt > TZ_MAX_TIMES ||
447 			sp->charcnt < 0 || sp->charcnt > TZ_MAX_CHARS ||
448 			(ttisstdcnt != sp->typecnt && ttisstdcnt != 0) ||
449 			(ttisgmtcnt != sp->typecnt && ttisgmtcnt != 0))
450 				return -1;
451 		if (nread - (p - u.buf) <
452 			sp->timecnt * stored +		/* ats */
453 			sp->timecnt +			/* types */
454 			sp->typecnt * 6 +		/* ttinfos */
455 			sp->charcnt +			/* chars */
456 			sp->leapcnt * (stored + 4) +	/* lsinfos */
457 			ttisstdcnt +			/* ttisstds */
458 			ttisgmtcnt)			/* ttisgmts */
459 				return -1;
460 		for (i = 0; i < sp->timecnt; ++i) {
461 			sp->ats[i] = (stored == 4) ?
462 				detzcode(p) : detzcode64(p);
463 			p += stored;
464 		}
465 		for (i = 0; i < sp->timecnt; ++i) {
466 			sp->types[i] = (unsigned char) *p++;
467 			if (sp->types[i] >= sp->typecnt)
468 				return -1;
469 		}
470 		for (i = 0; i < sp->typecnt; ++i) {
471 			register struct ttinfo *	ttisp;
472 
473 			ttisp = &sp->ttis[i];
474 			ttisp->tt_gmtoff = detzcode(p);
475 			p += 4;
476 			ttisp->tt_isdst = (unsigned char) *p++;
477 			if (ttisp->tt_isdst != 0 && ttisp->tt_isdst != 1)
478 				return -1;
479 			ttisp->tt_abbrind = (unsigned char) *p++;
480 			if (ttisp->tt_abbrind < 0 ||
481 				ttisp->tt_abbrind > sp->charcnt)
482 					return -1;
483 		}
484 		for (i = 0; i < sp->charcnt; ++i)
485 			sp->chars[i] = *p++;
486 		sp->chars[i] = '\0';	/* ensure '\0' at end */
487 		for (i = 0; i < sp->leapcnt; ++i) {
488 			register struct lsinfo *	lsisp;
489 
490 			lsisp = &sp->lsis[i];
491 			lsisp->ls_trans = (stored == 4) ?
492 				detzcode(p) : detzcode64(p);
493 			p += stored;
494 			lsisp->ls_corr = detzcode(p);
495 			p += 4;
496 		}
497 		for (i = 0; i < sp->typecnt; ++i) {
498 			register struct ttinfo *	ttisp;
499 
500 			ttisp = &sp->ttis[i];
501 			if (ttisstdcnt == 0)
502 				ttisp->tt_ttisstd = FALSE;
503 			else {
504 				ttisp->tt_ttisstd = *p++;
505 				if (ttisp->tt_ttisstd != TRUE &&
506 					ttisp->tt_ttisstd != FALSE)
507 						return -1;
508 			}
509 		}
510 		for (i = 0; i < sp->typecnt; ++i) {
511 			register struct ttinfo *	ttisp;
512 
513 			ttisp = &sp->ttis[i];
514 			if (ttisgmtcnt == 0)
515 				ttisp->tt_ttisgmt = FALSE;
516 			else {
517 				ttisp->tt_ttisgmt = *p++;
518 				if (ttisp->tt_ttisgmt != TRUE &&
519 					ttisp->tt_ttisgmt != FALSE)
520 						return -1;
521 			}
522 		}
523 		/*
524 		** Out-of-sort ats should mean we're running on a
525 		** signed time_t system but using a data file with
526 		** unsigned values (or vice versa).
527 		*/
528 		for (i = 0; i < sp->timecnt - 2; ++i)
529 			if (sp->ats[i] > sp->ats[i + 1]) {
530 				++i;
531 /* CONSTCOND */
532 				if (TYPE_SIGNED(time_t)) {
533 					/*
534 					** Ignore the end (easy).
535 					*/
536 					sp->timecnt = i;
537 				} else {
538 					/*
539 					** Ignore the beginning (harder).
540 					*/
541 					register int	j;
542 
543 					for (j = 0; j + i < sp->timecnt; ++j) {
544 						sp->ats[j] = sp->ats[j + i];
545 						sp->types[j] = sp->types[j + i];
546 					}
547 					sp->timecnt = j;
548 				}
549 				break;
550 			}
551 		/*
552 		** If this is an old file, we're done.
553 		*/
554 		if (u.tzhead.tzh_version[0] == '\0')
555 			break;
556 		nread -= p - u.buf;
557 		for (i = 0; i < nread; ++i)
558 			u.buf[i] = p[i];
559 		/*
560 		** If this is a narrow integer time_t system, we're done.
561 		*/
562 		if (stored >= (int) sizeof(time_t)
563 /* CONSTCOND */
564 				&& TYPE_INTEGRAL(time_t))
565 			break;
566 	}
567 	if (doextend && nread > 2 &&
568 		u.buf[0] == '\n' && u.buf[nread - 1] == '\n' &&
569 		sp->typecnt + 2 <= TZ_MAX_TYPES) {
570 			struct state	ts;
571 			register int	result;
572 
573 			u.buf[nread - 1] = '\0';
574 			result = tzparse(&u.buf[1], &ts, FALSE);
575 			if (result == 0 && ts.typecnt == 2 &&
576 				sp->charcnt + ts.charcnt <= TZ_MAX_CHARS) {
577 					for (i = 0; i < 2; ++i)
578 						ts.ttis[i].tt_abbrind +=
579 							sp->charcnt;
580 					for (i = 0; i < ts.charcnt; ++i)
581 						sp->chars[sp->charcnt++] =
582 							ts.chars[i];
583 					i = 0;
584 					while (i < ts.timecnt &&
585 						ts.ats[i] <=
586 						sp->ats[sp->timecnt - 1])
587 							++i;
588 					while (i < ts.timecnt &&
589 					    sp->timecnt < TZ_MAX_TIMES) {
590 						sp->ats[sp->timecnt] =
591 							ts.ats[i];
592 						sp->types[sp->timecnt] =
593 							sp->typecnt +
594 							ts.types[i];
595 						++sp->timecnt;
596 						++i;
597 					}
598 					sp->ttis[sp->typecnt++] = ts.ttis[0];
599 					sp->ttis[sp->typecnt++] = ts.ttis[1];
600 			}
601 	}
602 	if (sp->timecnt > 1) {
603 		for (i = 1; i < sp->timecnt; ++i)
604 			if (typesequiv(sp, sp->types[i], sp->types[0]) &&
605 				differ_by_repeat(sp->ats[i], sp->ats[0])) {
606 					sp->goback = TRUE;
607 					break;
608 				}
609 		for (i = sp->timecnt - 2; i >= 0; --i)
610 			if (typesequiv(sp, sp->types[sp->timecnt - 1],
611 				sp->types[i]) &&
612 				differ_by_repeat(sp->ats[sp->timecnt - 1],
613 				sp->ats[i])) {
614 					sp->goahead = TRUE;
615 					break;
616 		}
617 	}
618 	return 0;
619 }
620 
621 static int
622 typesequiv(sp, a, b)
623 const struct state * const	sp;
624 const int			a;
625 const int			b;
626 {
627 	register int	result;
628 
629 	if (sp == NULL ||
630 		a < 0 || a >= sp->typecnt ||
631 		b < 0 || b >= sp->typecnt)
632 			result = FALSE;
633 	else {
634 		register const struct ttinfo *	ap = &sp->ttis[a];
635 		register const struct ttinfo *	bp = &sp->ttis[b];
636 		result = ap->tt_gmtoff == bp->tt_gmtoff &&
637 			ap->tt_isdst == bp->tt_isdst &&
638 			ap->tt_ttisstd == bp->tt_ttisstd &&
639 			ap->tt_ttisgmt == bp->tt_ttisgmt &&
640 			strcmp(&sp->chars[ap->tt_abbrind],
641 			&sp->chars[bp->tt_abbrind]) == 0;
642 	}
643 	return result;
644 }
645 
646 static const int	mon_lengths[2][MONSPERYEAR] = {
647 	{ 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 },
648 	{ 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }
649 };
650 
651 static const int	year_lengths[2] = {
652 	DAYSPERNYEAR, DAYSPERLYEAR
653 };
654 
655 /*
656 ** Given a pointer into a time zone string, scan until a character that is not
657 ** a valid character in a zone name is found. Return a pointer to that
658 ** character.
659 */
660 
661 static const char *
662 getzname(strp)
663 register const char *	strp;
664 {
665 	register char	c;
666 
667 	while ((c = *strp) != '\0' && !is_digit(c) && c != ',' && c != '-' &&
668 		c != '+')
669 			++strp;
670 	return strp;
671 }
672 
673 /*
674 ** Given a pointer into an extended time zone string, scan until the ending
675 ** delimiter of the zone name is located. Return a pointer to the delimiter.
676 **
677 ** As with getzname above, the legal character set is actually quite
678 ** restricted, with other characters producing undefined results.
679 ** We don't do any checking here; checking is done later in common-case code.
680 */
681 
682 static const char *
683 getqzname(register const char *strp, const int delim)
684 {
685 	register int	c;
686 
687 	while ((c = *strp) != '\0' && c != delim)
688 		++strp;
689 	return strp;
690 }
691 
692 /*
693 ** Given a pointer into a time zone string, extract a number from that string.
694 ** Check that the number is within a specified range; if it is not, return
695 ** NULL.
696 ** Otherwise, return a pointer to the first character not part of the number.
697 */
698 
699 static const char *
700 getnum(strp, nump, min, max)
701 register const char *	strp;
702 int * const		nump;
703 const int		min;
704 const int		max;
705 {
706 	register char	c;
707 	register int	num;
708 
709 	if (strp == NULL || !is_digit(c = *strp)) {
710 		errno = EINVAL;
711 		return NULL;
712 	}
713 	num = 0;
714 	do {
715 		num = num * 10 + (c - '0');
716 		if (num > max) {
717 			errno = EOVERFLOW;
718 			return NULL;	/* illegal value */
719 		}
720 		c = *++strp;
721 	} while (is_digit(c));
722 	if (num < min) {
723 		errno = EINVAL;
724 		return NULL;		/* illegal value */
725 	}
726 	*nump = num;
727 	return strp;
728 }
729 
730 /*
731 ** Given a pointer into a time zone string, extract a number of seconds,
732 ** in hh[:mm[:ss]] form, from the string.
733 ** If any error occurs, return NULL.
734 ** Otherwise, return a pointer to the first character not part of the number
735 ** of seconds.
736 */
737 
738 static const char *
739 getsecs(strp, secsp)
740 register const char *	strp;
741 long * const		secsp;
742 {
743 	int	num;
744 
745 	/*
746 	** `HOURSPERDAY * DAYSPERWEEK - 1' allows quasi-Posix rules like
747 	** "M10.4.6/26", which does not conform to Posix,
748 	** but which specifies the equivalent of
749 	** ``02:00 on the first Sunday on or after 23 Oct''.
750 	*/
751 	strp = getnum(strp, &num, 0, HOURSPERDAY * DAYSPERWEEK - 1);
752 	if (strp == NULL)
753 		return NULL;
754 	*secsp = num * (long) SECSPERHOUR;
755 	if (*strp == ':') {
756 		++strp;
757 		strp = getnum(strp, &num, 0, MINSPERHOUR - 1);
758 		if (strp == NULL)
759 			return NULL;
760 		*secsp += num * SECSPERMIN;
761 		if (*strp == ':') {
762 			++strp;
763 			/* `SECSPERMIN' allows for leap seconds. */
764 			strp = getnum(strp, &num, 0, SECSPERMIN);
765 			if (strp == NULL)
766 				return NULL;
767 			*secsp += num;
768 		}
769 	}
770 	return strp;
771 }
772 
773 /*
774 ** Given a pointer into a time zone string, extract an offset, in
775 ** [+-]hh[:mm[:ss]] form, from the string.
776 ** If any error occurs, return NULL.
777 ** Otherwise, return a pointer to the first character not part of the time.
778 */
779 
780 static const char *
781 getoffset(strp, offsetp)
782 register const char *	strp;
783 long * const		offsetp;
784 {
785 	register int	neg = 0;
786 
787 	if (*strp == '-') {
788 		neg = 1;
789 		++strp;
790 	} else if (*strp == '+')
791 		++strp;
792 	strp = getsecs(strp, offsetp);
793 	if (strp == NULL)
794 		return NULL;		/* illegal time */
795 	if (neg)
796 		*offsetp = -*offsetp;
797 	return strp;
798 }
799 
800 /*
801 ** Given a pointer into a time zone string, extract a rule in the form
802 ** date[/time]. See POSIX section 8 for the format of "date" and "time".
803 ** If a valid rule is not found, return NULL.
804 ** Otherwise, return a pointer to the first character not part of the rule.
805 */
806 
807 static const char *
808 getrule(strp, rulep)
809 const char *			strp;
810 register 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(janfirst, year, rulep, offset)
863 const time_t				janfirst;
864 const int				year;
865 register const struct rule * const	rulep;
866 const long				offset;
867 {
868 	register int	leapyear;
869 	register time_t	value;
870 	register int	i;
871 	int		d, m1, yy0, yy1, yy2, dow;
872 
873 	INITIALIZE(value);
874 	leapyear = isleap(year);
875 	switch (rulep->r_type) {
876 
877 	case JULIAN_DAY:
878 		/*
879 		** Jn - Julian day, 1 == January 1, 60 == March 1 even in leap
880 		** years.
881 		** In non-leap years, or if the day number is 59 or less, just
882 		** add SECSPERDAY times the day number-1 to the time of
883 		** January 1, midnight, to get the day.
884 		*/
885 		value = janfirst + (rulep->r_day - 1) * SECSPERDAY;
886 		if (leapyear && rulep->r_day >= 60)
887 			value += SECSPERDAY;
888 		break;
889 
890 	case DAY_OF_YEAR:
891 		/*
892 		** n - day of year.
893 		** Just add SECSPERDAY times the day number to the time of
894 		** January 1, midnight, to get the day.
895 		*/
896 		value = janfirst + rulep->r_day * SECSPERDAY;
897 		break;
898 
899 	case MONTH_NTH_DAY_OF_WEEK:
900 		/*
901 		** Mm.n.d - nth "dth day" of month m.
902 		*/
903 		value = janfirst;
904 		for (i = 0; i < rulep->r_mon - 1; ++i)
905 			value += mon_lengths[leapyear][i] * SECSPERDAY;
906 
907 		/*
908 		** Use Zeller's Congruence to get day-of-week of first day of
909 		** month.
910 		*/
911 		m1 = (rulep->r_mon + 9) % 12 + 1;
912 		yy0 = (rulep->r_mon <= 2) ? (year - 1) : year;
913 		yy1 = yy0 / 100;
914 		yy2 = yy0 % 100;
915 		dow = ((26 * m1 - 2) / 10 +
916 			1 + yy2 + yy2 / 4 + yy1 / 4 - 2 * yy1) % 7;
917 		if (dow < 0)
918 			dow += DAYSPERWEEK;
919 
920 		/*
921 		** "dow" is the day-of-week of the first day of the month. Get
922 		** the day-of-month (zero-origin) of the first "dow" day of the
923 		** month.
924 		*/
925 		d = rulep->r_day - dow;
926 		if (d < 0)
927 			d += DAYSPERWEEK;
928 		for (i = 1; i < rulep->r_week; ++i) {
929 			if (d + DAYSPERWEEK >=
930 				mon_lengths[leapyear][rulep->r_mon - 1])
931 					break;
932 			d += DAYSPERWEEK;
933 		}
934 
935 		/*
936 		** "d" is the day-of-month (zero-origin) of the day we want.
937 		*/
938 		value += d * SECSPERDAY;
939 		break;
940 	}
941 
942 	/*
943 	** "value" is the Epoch-relative time of 00:00:00 UTC on the day in
944 	** question. To get the Epoch-relative time of the specified local
945 	** time on that day, add the transition time and the current offset
946 	** from UTC.
947 	*/
948 	return value + rulep->r_time + offset;
949 }
950 
951 /*
952 ** Given a POSIX section 8-style TZ string, fill in the rule tables as
953 ** appropriate.
954 */
955 
956 static int
957 tzparse(name, sp, lastditch)
958 const char *			name;
959 register struct state * const	sp;
960 const int			lastditch;
961 {
962 	const char *			stdname;
963 	const char *			dstname;
964 	size_t				stdlen;
965 	size_t				dstlen;
966 	long				stdoffset;
967 	long				dstoffset;
968 	register time_t *		atp;
969 	register unsigned char *	typep;
970 	register char *			cp;
971 	register int			load_result;
972 
973 	INITIALIZE(dstname);
974 	stdname = name;
975 	if (lastditch) {
976 		stdlen = strlen(name);	/* length of standard zone name */
977 		name += stdlen;
978 		if (stdlen >= sizeof sp->chars)
979 			stdlen = (sizeof sp->chars) - 1;
980 		stdoffset = 0;
981 	} else {
982 		if (*name == '<') {
983 			name++;
984 			stdname = name;
985 			name = getqzname(name, '>');
986 			if (*name != '>')
987 				return (-1);
988 			stdlen = name - stdname;
989 			name++;
990 		} else {
991 			name = getzname(name);
992 			stdlen = name - stdname;
993 		}
994 		if (*name == '\0')
995 			return -1;
996 		name = getoffset(name, &stdoffset);
997 		if (name == NULL)
998 			return -1;
999 	}
1000 	load_result = tzload(TZDEFRULES, sp, FALSE);
1001 	if (load_result != 0)
1002 		sp->leapcnt = 0;		/* so, we're off a little */
1003 	if (*name != '\0') {
1004 		if (*name == '<') {
1005 			dstname = ++name;
1006 			name = getqzname(name, '>');
1007 			if (*name != '>')
1008 				return -1;
1009 			dstlen = name - dstname;
1010 			name++;
1011 		} else {
1012 			dstname = name;
1013 			name = getzname(name);
1014 			dstlen = name - dstname; /* length of DST zone name */
1015 		}
1016 		if (*name != '\0' && *name != ',' && *name != ';') {
1017 			name = getoffset(name, &dstoffset);
1018 			if (name == NULL)
1019 				return -1;
1020 		} else	dstoffset = stdoffset - SECSPERHOUR;
1021 		if (*name == '\0' && load_result != 0)
1022 			name = TZDEFRULESTRING;
1023 		if (*name == ',' || *name == ';') {
1024 			struct rule	start;
1025 			struct rule	end;
1026 			register int	year;
1027 			register time_t	janfirst;
1028 			time_t		starttime;
1029 			time_t		endtime;
1030 
1031 			++name;
1032 			if ((name = getrule(name, &start)) == NULL)
1033 				return -1;
1034 			if (*name++ != ',')
1035 				return -1;
1036 			if ((name = getrule(name, &end)) == NULL)
1037 				return -1;
1038 			if (*name != '\0')
1039 				return -1;
1040 			sp->typecnt = 2;	/* standard time and DST */
1041 			/*
1042 			** Two transitions per year, from EPOCH_YEAR forward.
1043 			*/
1044 			sp->ttis[0].tt_gmtoff = -dstoffset;
1045 			sp->ttis[0].tt_isdst = 1;
1046 			sp->ttis[0].tt_abbrind = stdlen + 1;
1047 			sp->ttis[1].tt_gmtoff = -stdoffset;
1048 			sp->ttis[1].tt_isdst = 0;
1049 			sp->ttis[1].tt_abbrind = 0;
1050 			atp = sp->ats;
1051 			typep = sp->types;
1052 			janfirst = 0;
1053 			sp->timecnt = 0;
1054 			for (year = EPOCH_YEAR;
1055 			    sp->timecnt + 2 <= TZ_MAX_TIMES;
1056 			    ++year) {
1057 			    	time_t	newfirst;
1058 
1059 				starttime = transtime(janfirst, year, &start,
1060 					stdoffset);
1061 				endtime = transtime(janfirst, year, &end,
1062 					dstoffset);
1063 				if (starttime > endtime) {
1064 					*atp++ = endtime;
1065 					*typep++ = 1;	/* DST ends */
1066 					*atp++ = starttime;
1067 					*typep++ = 0;	/* DST begins */
1068 				} else {
1069 					*atp++ = starttime;
1070 					*typep++ = 0;	/* DST begins */
1071 					*atp++ = endtime;
1072 					*typep++ = 1;	/* DST ends */
1073 				}
1074 				sp->timecnt += 2;
1075 				newfirst = janfirst;
1076 				newfirst += year_lengths[isleap(year)] *
1077 					SECSPERDAY;
1078 				if (newfirst <= janfirst)
1079 					break;
1080 				janfirst = newfirst;
1081 			}
1082 		} else {
1083 			register long	theirstdoffset;
1084 			register long	theirdstoffset;
1085 			register long	theiroffset;
1086 			register int	isdst;
1087 			register int	i;
1088 			register int	j;
1089 
1090 			if (*name != '\0')
1091 				return -1;
1092 			/*
1093 			** Initial values of theirstdoffset
1094 			*/
1095 			theirstdoffset = 0;
1096 			for (i = 0; i < sp->timecnt; ++i) {
1097 				j = sp->types[i];
1098 				if (!sp->ttis[j].tt_isdst) {
1099 					theirstdoffset =
1100 						-sp->ttis[j].tt_gmtoff;
1101 					break;
1102 				}
1103 			}
1104 			theirdstoffset = 0;
1105 			for (i = 0; i < sp->timecnt; ++i) {
1106 				j = sp->types[i];
1107 				if (sp->ttis[j].tt_isdst) {
1108 					theirdstoffset =
1109 						-sp->ttis[j].tt_gmtoff;
1110 					break;
1111 				}
1112 			}
1113 			/*
1114 			** Initially we're assumed to be in standard time.
1115 			*/
1116 			isdst = FALSE;
1117 			theiroffset = theirstdoffset;
1118 			/*
1119 			** Now juggle transition times and types
1120 			** tracking offsets as you do.
1121 			*/
1122 			for (i = 0; i < sp->timecnt; ++i) {
1123 				j = sp->types[i];
1124 				sp->types[i] = sp->ttis[j].tt_isdst;
1125 				if (sp->ttis[j].tt_ttisgmt) {
1126 					/* No adjustment to transition time */
1127 				} else {
1128 					/*
1129 					** If summer time is in effect, and the
1130 					** transition time was not specified as
1131 					** standard time, add the summer time
1132 					** offset to the transition time;
1133 					** otherwise, add the standard time
1134 					** offset to the transition time.
1135 					*/
1136 					/*
1137 					** Transitions from DST to DDST
1138 					** will effectively disappear since
1139 					** POSIX provides for only one DST
1140 					** offset.
1141 					*/
1142 					if (isdst && !sp->ttis[j].tt_ttisstd) {
1143 						sp->ats[i] += dstoffset -
1144 							theirdstoffset;
1145 					} else {
1146 						sp->ats[i] += stdoffset -
1147 							theirstdoffset;
1148 					}
1149 				}
1150 				theiroffset = -sp->ttis[j].tt_gmtoff;
1151 				if (!sp->ttis[j].tt_isdst)
1152 					theirstdoffset = theiroffset;
1153 				else	theirdstoffset = theiroffset;
1154 			}
1155 			/*
1156 			** Finally, fill in ttis.
1157 			** ttisstd and ttisgmt need not be handled.
1158 			*/
1159 			sp->ttis[0].tt_gmtoff = -stdoffset;
1160 			sp->ttis[0].tt_isdst = FALSE;
1161 			sp->ttis[0].tt_abbrind = 0;
1162 			sp->ttis[1].tt_gmtoff = -dstoffset;
1163 			sp->ttis[1].tt_isdst = TRUE;
1164 			sp->ttis[1].tt_abbrind = stdlen + 1;
1165 			sp->typecnt = 2;
1166 		}
1167 	} else {
1168 		dstlen = 0;
1169 		sp->typecnt = 1;		/* only standard time */
1170 		sp->timecnt = 0;
1171 		sp->ttis[0].tt_gmtoff = -stdoffset;
1172 		sp->ttis[0].tt_isdst = 0;
1173 		sp->ttis[0].tt_abbrind = 0;
1174 	}
1175 	sp->charcnt = stdlen + 1;
1176 	if (dstlen != 0)
1177 		sp->charcnt += dstlen + 1;
1178 	if ((size_t) sp->charcnt > sizeof sp->chars)
1179 		return -1;
1180 	cp = sp->chars;
1181 	(void) strncpy(cp, stdname, stdlen);
1182 	cp += stdlen;
1183 	*cp++ = '\0';
1184 	if (dstlen != 0) {
1185 		(void) strncpy(cp, dstname, dstlen);
1186 		*(cp + dstlen) = '\0';
1187 	}
1188 	return 0;
1189 }
1190 
1191 static void
1192 gmtload(sp)
1193 struct state * const	sp;
1194 {
1195 	if (tzload(gmt, sp, TRUE) != 0)
1196 		(void) tzparse(gmt, sp, TRUE);
1197 }
1198 
1199 static void
1200 tzsetwall_unlocked(void)
1201 {
1202 	if (lcl_is_set < 0)
1203 		return;
1204 	lcl_is_set = -1;
1205 
1206 #ifdef ALL_STATE
1207 	if (lclptr == NULL) {
1208 		int saveerrno = errno;
1209 		lclptr = calloc(1, sizeof *lclptr);
1210 		errno = saveerrno;
1211 		if (lclptr == NULL) {
1212 			settzname();	/* all we can do */
1213 			return;
1214 		}
1215 	}
1216 #endif /* defined ALL_STATE */
1217 	if (tzload((char *) NULL, lclptr, TRUE) != 0)
1218 		gmtload(lclptr);
1219 	settzname();
1220 }
1221 
1222 #ifndef STD_INSPIRED
1223 /*
1224 ** A non-static declaration of tzsetwall in a system header file
1225 ** may cause a warning about this upcoming static declaration...
1226 */
1227 static
1228 #endif /* !defined STD_INSPIRED */
1229 void
1230 tzsetwall(void)
1231 {
1232 	rwlock_wrlock(&lcl_lock);
1233 	tzsetwall_unlocked();
1234 	rwlock_unlock(&lcl_lock);
1235 }
1236 
1237 #ifndef STD_INSPIRED
1238 /*
1239 ** A non-static declaration of tzsetwall in a system header file
1240 ** may cause a warning about this upcoming static declaration...
1241 */
1242 static
1243 #endif /* !defined STD_INSPIRED */
1244 void
1245 tzset_unlocked(void)
1246 {
1247 	register const char *	name;
1248 	int saveerrno;
1249 
1250 	saveerrno = errno;
1251 	name = getenv("TZ");
1252 	errno = saveerrno;
1253 	if (name == NULL) {
1254 		tzsetwall_unlocked();
1255 		return;
1256 	}
1257 
1258 	if (lcl_is_set > 0 && strcmp(lcl_TZname, name) == 0)
1259 		return;
1260 	lcl_is_set = strlen(name) < sizeof lcl_TZname;
1261 	if (lcl_is_set)
1262 		(void)strlcpy(lcl_TZname, name, sizeof(lcl_TZname));
1263 
1264 #ifdef ALL_STATE
1265 	if (lclptr == NULL) {
1266 		saveerrno = errno;
1267 		lclptr = calloc(1, sizeof *lclptr);
1268 		errno = saveerrno;
1269 		if (lclptr == NULL) {
1270 			settzname();	/* all we can do */
1271 			return;
1272 		}
1273 	}
1274 #endif /* defined ALL_STATE */
1275 	if (*name == '\0') {
1276 		/*
1277 		** User wants it fast rather than right.
1278 		*/
1279 		lclptr->leapcnt = 0;		/* so, we're off a little */
1280 		lclptr->timecnt = 0;
1281 		lclptr->typecnt = 0;
1282 		lclptr->ttis[0].tt_isdst = 0;
1283 		lclptr->ttis[0].tt_gmtoff = 0;
1284 		lclptr->ttis[0].tt_abbrind = 0;
1285 		(void) strlcpy(lclptr->chars, gmt, sizeof(lclptr->chars));
1286 	} else if (tzload(name, lclptr, TRUE) != 0)
1287 		if (name[0] == ':' || tzparse(name, lclptr, FALSE) != 0)
1288 			(void) gmtload(lclptr);
1289 	settzname();
1290 }
1291 
1292 void
1293 tzset(void)
1294 {
1295 	rwlock_wrlock(&lcl_lock);
1296 	tzset_unlocked();
1297 	rwlock_unlock(&lcl_lock);
1298 }
1299 
1300 /*
1301 ** The easy way to behave "as if no library function calls" localtime
1302 ** is to not call it--so we drop its guts into "localsub", which can be
1303 ** freely called. (And no, the PANS doesn't require the above behavior--
1304 ** but it *is* desirable.)
1305 **
1306 ** The unused offset argument is for the benefit of mktime variants.
1307 */
1308 
1309 /*ARGSUSED*/
1310 static struct tm *
1311 localsub(timep, offset, tmp)
1312 const time_t * const	timep;
1313 const long		offset;
1314 struct tm * const	tmp;
1315 {
1316 	register struct state *		sp;
1317 	register const struct ttinfo *	ttisp;
1318 	register int			i;
1319 	register struct tm *		result;
1320 	const time_t			t = *timep;
1321 
1322 	sp = lclptr;
1323 #ifdef ALL_STATE
1324 	if (sp == NULL)
1325 		return gmtsub(timep, offset, tmp);
1326 #endif /* defined ALL_STATE */
1327 	if ((sp->goback && t < sp->ats[0]) ||
1328 		(sp->goahead && t > sp->ats[sp->timecnt - 1])) {
1329 			time_t			newt = t;
1330 			register time_t		seconds;
1331 			register time_t		tcycles;
1332 			register int_fast64_t	icycles;
1333 
1334 			if (t < sp->ats[0])
1335 				seconds = sp->ats[0] - t;
1336 			else	seconds = t - sp->ats[sp->timecnt - 1];
1337 			--seconds;
1338 			tcycles = seconds / YEARSPERREPEAT / AVGSECSPERYEAR;
1339 			++tcycles;
1340 			icycles = tcycles;
1341 			if (tcycles - icycles >= 1 || icycles - tcycles >= 1)
1342 				return NULL;
1343 			seconds = (time_t) icycles;
1344 			seconds *= YEARSPERREPEAT;
1345 			seconds *= AVGSECSPERYEAR;
1346 			if (t < sp->ats[0])
1347 				newt += seconds;
1348 			else	newt -= seconds;
1349 			if (newt < sp->ats[0] ||
1350 				newt > sp->ats[sp->timecnt - 1]) {
1351 					errno = EOVERFLOW;
1352 					return NULL;	/* "cannot happen" */
1353 			}
1354 			result = localsub(&newt, offset, tmp);
1355 			if (result == tmp) {
1356 				register time_t	newy;
1357 
1358 				newy = tmp->tm_year;
1359 				if (t < sp->ats[0])
1360 					newy -= (time_t)icycles * YEARSPERREPEAT;
1361 				else	newy += (time_t)icycles * YEARSPERREPEAT;
1362 				tmp->tm_year = (int)newy;
1363 				if (tmp->tm_year != newy) {
1364 					errno = EOVERFLOW;
1365 					return NULL;
1366 				}
1367 			}
1368 			return result;
1369 	}
1370 	if (sp->timecnt == 0 || t < sp->ats[0]) {
1371 		i = 0;
1372 		while (sp->ttis[i].tt_isdst)
1373 			if (++i >= sp->typecnt) {
1374 				i = 0;
1375 				break;
1376 			}
1377 	} else {
1378 		register int	lo = 1;
1379 		register int	hi = sp->timecnt;
1380 
1381 		while (lo < hi) {
1382 			register int	mid = (lo + hi) / 2;
1383 
1384 			if (t < sp->ats[mid])
1385 				hi = mid;
1386 			else	lo = mid + 1;
1387 		}
1388 		i = (int) sp->types[lo - 1];
1389 	}
1390 	ttisp = &sp->ttis[i];
1391 	/*
1392 	** To get (wrong) behavior that's compatible with System V Release 2.0
1393 	** you'd replace the statement below with
1394 	**	t += ttisp->tt_gmtoff;
1395 	**	timesub(&t, 0L, sp, tmp);
1396 	*/
1397 	result = timesub(&t, ttisp->tt_gmtoff, sp, tmp);
1398 	tmp->tm_isdst = ttisp->tt_isdst;
1399 	tzname[tmp->tm_isdst] = &sp->chars[ttisp->tt_abbrind];
1400 #ifdef TM_ZONE
1401 	tmp->TM_ZONE = &sp->chars[ttisp->tt_abbrind];
1402 #endif /* defined TM_ZONE */
1403 	return result;
1404 }
1405 
1406 struct tm *
1407 localtime(timep)
1408 const time_t * const	timep;
1409 {
1410 	struct tm *result;
1411 
1412 	rwlock_wrlock(&lcl_lock);
1413 	tzset_unlocked();
1414 	result = localsub(timep, 0L, &tm);
1415 	rwlock_unlock(&lcl_lock);
1416 	return result;
1417 }
1418 
1419 /*
1420 ** Re-entrant version of localtime.
1421 */
1422 
1423 struct tm *
1424 localtime_r(timep, tmp)
1425 const time_t * const	timep;
1426 struct tm *		tmp;
1427 {
1428 	struct tm *result;
1429 
1430 	rwlock_rdlock(&lcl_lock);
1431 	tzset_unlocked();
1432 	result = localsub(timep, 0L, tmp);
1433 	rwlock_unlock(&lcl_lock);
1434 	return result;
1435 }
1436 
1437 /*
1438 ** gmtsub is to gmtime as localsub is to localtime.
1439 */
1440 
1441 static struct tm *
1442 gmtsub(timep, offset, tmp)
1443 const time_t * const	timep;
1444 const long		offset;
1445 struct tm * const	tmp;
1446 {
1447 	register struct tm *	result;
1448 #ifdef _REENTRANT
1449 	static mutex_t gmt_mutex = MUTEX_INITIALIZER;
1450 #endif
1451 
1452 	mutex_lock(&gmt_mutex);
1453 	if (!gmt_is_set) {
1454 #ifdef ALL_STATE
1455 		int saveerrno;
1456 #endif
1457 		gmt_is_set = TRUE;
1458 #ifdef ALL_STATE
1459 		saveerrno = errno;
1460 		gmtptr = calloc(1, sizeof *gmtptr);
1461 		errno = saveerrno;
1462 		if (gmtptr != NULL)
1463 #endif /* defined ALL_STATE */
1464 			gmtload(gmtptr);
1465 	}
1466 	mutex_unlock(&gmt_mutex);
1467 	result = timesub(timep, offset, gmtptr, tmp);
1468 #ifdef TM_ZONE
1469 	/*
1470 	** Could get fancy here and deliver something such as
1471 	** "UTC+xxxx" or "UTC-xxxx" if offset is non-zero,
1472 	** but this is no time for a treasure hunt.
1473 	*/
1474 	if (offset != 0)
1475 		tmp->TM_ZONE = (__aconst char *)__UNCONST(wildabbr);
1476 	else {
1477 #ifdef ALL_STATE
1478 		if (gmtptr == NULL)
1479 			tmp->TM_ZONE = (__aconst char *)__UNCONST(gmt);
1480 		else	tmp->TM_ZONE = gmtptr->chars;
1481 #endif /* defined ALL_STATE */
1482 #ifndef ALL_STATE
1483 		tmp->TM_ZONE = gmtptr->chars;
1484 #endif /* State Farm */
1485 	}
1486 #endif /* defined TM_ZONE */
1487 	return result;
1488 }
1489 
1490 struct tm *
1491 gmtime(timep)
1492 const time_t * const	timep;
1493 {
1494 	return gmtsub(timep, 0L, &tm);
1495 }
1496 
1497 /*
1498 ** Re-entrant version of gmtime.
1499 */
1500 
1501 struct tm *
1502 gmtime_r(timep, tmp)
1503 const time_t * const	timep;
1504 struct tm *		tmp;
1505 {
1506 	return gmtsub(timep, 0L, tmp);
1507 }
1508 
1509 #ifdef STD_INSPIRED
1510 
1511 struct tm *
1512 offtime(timep, offset)
1513 const time_t * const	timep;
1514 const long		offset;
1515 {
1516 	return gmtsub(timep, offset, &tm);
1517 }
1518 
1519 #endif /* defined STD_INSPIRED */
1520 
1521 /*
1522 ** Return the number of leap years through the end of the given year
1523 ** where, to make the math easy, the answer for year zero is defined as zero.
1524 */
1525 
1526 static int
1527 leaps_thru_end_of(y)
1528 register const int	y;
1529 {
1530 	return (y >= 0) ? (y / 4 - y / 100 + y / 400) :
1531 		-(leaps_thru_end_of(-(y + 1)) + 1);
1532 }
1533 
1534 static struct tm *
1535 timesub(timep, offset, sp, tmp)
1536 const time_t * const			timep;
1537 const long				offset;
1538 register const struct state * const	sp;
1539 register struct tm * const		tmp;
1540 {
1541 	register const struct lsinfo *	lp;
1542 	register time_t			tdays;
1543 	register int			idays;	/* unsigned would be so 2003 */
1544 	register long			rem;
1545 	int				y;
1546 	register const int *		ip;
1547 	register long			corr;
1548 	register int			hit;
1549 	register int			i;
1550 
1551 	corr = 0;
1552 	hit = 0;
1553 #ifdef ALL_STATE
1554 	i = (sp == NULL) ? 0 : sp->leapcnt;
1555 #endif /* defined ALL_STATE */
1556 #ifndef ALL_STATE
1557 	i = sp->leapcnt;
1558 #endif /* State Farm */
1559 	while (--i >= 0) {
1560 		lp = &sp->lsis[i];
1561 		if (*timep >= lp->ls_trans) {
1562 			if (*timep == lp->ls_trans) {
1563 				hit = ((i == 0 && lp->ls_corr > 0) ||
1564 					lp->ls_corr > sp->lsis[i - 1].ls_corr);
1565 				if (hit)
1566 					while (i > 0 &&
1567 						sp->lsis[i].ls_trans ==
1568 						sp->lsis[i - 1].ls_trans + 1 &&
1569 						sp->lsis[i].ls_corr ==
1570 						sp->lsis[i - 1].ls_corr + 1) {
1571 							++hit;
1572 							--i;
1573 					}
1574 			}
1575 			corr = lp->ls_corr;
1576 			break;
1577 		}
1578 	}
1579 	y = EPOCH_YEAR;
1580 	tdays = *timep / SECSPERDAY;
1581 	rem = (long) (*timep - tdays * SECSPERDAY);
1582 	while (tdays < 0 || tdays >= year_lengths[isleap(y)]) {
1583 		int		newy;
1584 		register time_t	tdelta;
1585 		register int	idelta;
1586 		register int	leapdays;
1587 
1588 		tdelta = tdays / DAYSPERLYEAR;
1589 		idelta = (int) tdelta;
1590 		if (tdelta - idelta >= 1 || idelta - tdelta >= 1) {
1591 			errno = EOVERFLOW;
1592 			return NULL;
1593 		}
1594 		if (idelta == 0)
1595 			idelta = (tdays < 0) ? -1 : 1;
1596 		newy = y;
1597 		if (increment_overflow(&newy, idelta)) {
1598 			errno = EOVERFLOW;
1599 			return NULL;
1600 		}
1601 		leapdays = leaps_thru_end_of(newy - 1) -
1602 			leaps_thru_end_of(y - 1);
1603 		tdays -= ((time_t) newy - y) * DAYSPERNYEAR;
1604 		tdays -= leapdays;
1605 		y = newy;
1606 	}
1607 	{
1608 		register long	seconds;
1609 
1610 		seconds = tdays * SECSPERDAY + 0.5;
1611 		tdays = seconds / SECSPERDAY;
1612 		rem += (long) (seconds - tdays * SECSPERDAY);
1613 	}
1614 	/*
1615 	** Given the range, we can now fearlessly cast...
1616 	*/
1617 	idays = (int) tdays;
1618 	rem += offset - corr;
1619 	while (rem < 0) {
1620 		rem += SECSPERDAY;
1621 		--idays;
1622 	}
1623 	while (rem >= SECSPERDAY) {
1624 		rem -= SECSPERDAY;
1625 		++idays;
1626 	}
1627 	while (idays < 0) {
1628 		if (increment_overflow(&y, -1)) {
1629 			errno = EOVERFLOW;
1630 			return NULL;
1631 		}
1632 		idays += year_lengths[isleap(y)];
1633 	}
1634 	while (idays >= year_lengths[isleap(y)]) {
1635 		idays -= year_lengths[isleap(y)];
1636 		if (increment_overflow(&y, 1)) {
1637 			errno = EOVERFLOW;
1638 			return NULL;
1639 		}
1640 	}
1641 	tmp->tm_year = y;
1642 	if (increment_overflow(&tmp->tm_year, -TM_YEAR_BASE)) {
1643 		errno = EOVERFLOW;
1644 		return NULL;
1645 	}
1646 	tmp->tm_yday = idays;
1647 	/*
1648 	** The "extra" mods below avoid overflow problems.
1649 	*/
1650 	tmp->tm_wday = EPOCH_WDAY +
1651 		((y - EPOCH_YEAR) % DAYSPERWEEK) *
1652 		(DAYSPERNYEAR % DAYSPERWEEK) +
1653 		leaps_thru_end_of(y - 1) -
1654 		leaps_thru_end_of(EPOCH_YEAR - 1) +
1655 		idays;
1656 	tmp->tm_wday %= DAYSPERWEEK;
1657 	if (tmp->tm_wday < 0)
1658 		tmp->tm_wday += DAYSPERWEEK;
1659 	tmp->tm_hour = (int) (rem / SECSPERHOUR);
1660 	rem %= SECSPERHOUR;
1661 	tmp->tm_min = (int) (rem / SECSPERMIN);
1662 	/*
1663 	** A positive leap second requires a special
1664 	** representation. This uses "... ??:59:60" et seq.
1665 	*/
1666 	tmp->tm_sec = (int) (rem % SECSPERMIN) + hit;
1667 	ip = mon_lengths[isleap(y)];
1668 	for (tmp->tm_mon = 0; idays >= ip[tmp->tm_mon]; ++(tmp->tm_mon))
1669 		idays -= ip[tmp->tm_mon];
1670 	tmp->tm_mday = (int) (idays + 1);
1671 	tmp->tm_isdst = 0;
1672 #ifdef TM_GMTOFF
1673 	tmp->TM_GMTOFF = offset;
1674 #endif /* defined TM_GMTOFF */
1675 	return tmp;
1676 }
1677 
1678 char *
1679 ctime(timep)
1680 const time_t * const	timep;
1681 {
1682 /*
1683 ** Section 4.12.3.2 of X3.159-1989 requires that
1684 **	The ctime function converts the calendar time pointed to by timer
1685 **	to local time in the form of a string. It is equivalent to
1686 **		asctime(localtime(timer))
1687 */
1688 	struct tm *rtm = localtime(timep);
1689 	if (rtm == NULL)
1690 		return NULL;
1691 	return asctime(rtm);
1692 }
1693 
1694 char *
1695 ctime_r(timep, buf)
1696 const time_t * const	timep;
1697 char *			buf;
1698 {
1699 	struct tm	mytm, *rtm;
1700 
1701 	rtm = localtime_r(timep, &mytm);
1702 	if (rtm == NULL)
1703 		return NULL;
1704 	return asctime_r(rtm, buf);
1705 }
1706 
1707 /*
1708 ** Adapted from code provided by Robert Elz, who writes:
1709 **	The "best" way to do mktime I think is based on an idea of Bob
1710 **	Kridle's (so its said...) from a long time ago.
1711 **	It does a binary search of the time_t space. Since time_t's are
1712 **	just 32 bits, its a max of 32 iterations (even at 64 bits it
1713 **	would still be very reasonable).
1714 */
1715 
1716 #ifndef WRONG
1717 #define WRONG	(-1)
1718 #endif /* !defined WRONG */
1719 
1720 /*
1721 ** Simplified normalize logic courtesy Paul Eggert.
1722 */
1723 
1724 static int
1725 increment_overflow(number, delta)
1726 int *	number;
1727 int	delta;
1728 {
1729 	int	number0;
1730 
1731 	number0 = *number;
1732 	*number += delta;
1733 	return (*number < number0) != (delta < 0);
1734 }
1735 
1736 static int
1737 long_increment_overflow(number, delta)
1738 long *	number;
1739 int	delta;
1740 {
1741 	long	number0;
1742 
1743 	number0 = *number;
1744 	*number += delta;
1745 	return (*number < number0) != (delta < 0);
1746 }
1747 
1748 static int
1749 normalize_overflow(tensptr, unitsptr, base)
1750 int * const	tensptr;
1751 int * const	unitsptr;
1752 const int	base;
1753 {
1754 	register int	tensdelta;
1755 
1756 	tensdelta = (*unitsptr >= 0) ?
1757 		(*unitsptr / base) :
1758 		(-1 - (-1 - *unitsptr) / base);
1759 	*unitsptr -= tensdelta * base;
1760 	return increment_overflow(tensptr, tensdelta);
1761 }
1762 
1763 static int
1764 long_normalize_overflow(tensptr, unitsptr, base)
1765 long * const	tensptr;
1766 int * const	unitsptr;
1767 const int	base;
1768 {
1769 	register int	tensdelta;
1770 
1771 	tensdelta = (*unitsptr >= 0) ?
1772 		(*unitsptr / base) :
1773 		(-1 - (-1 - *unitsptr) / base);
1774 	*unitsptr -= tensdelta * base;
1775 	return long_increment_overflow(tensptr, tensdelta);
1776 }
1777 
1778 static int
1779 tmcomp(atmp, btmp)
1780 register const struct tm * const atmp;
1781 register const struct tm * const btmp;
1782 {
1783 	register int	result;
1784 
1785 	if ((result = (atmp->tm_year - btmp->tm_year)) == 0 &&
1786 		(result = (atmp->tm_mon - btmp->tm_mon)) == 0 &&
1787 		(result = (atmp->tm_mday - btmp->tm_mday)) == 0 &&
1788 		(result = (atmp->tm_hour - btmp->tm_hour)) == 0 &&
1789 		(result = (atmp->tm_min - btmp->tm_min)) == 0)
1790 			result = atmp->tm_sec - btmp->tm_sec;
1791 	return result;
1792 }
1793 
1794 static time_t
1795 time2sub(tmp, funcp, offset, okayp, do_norm_secs)
1796 struct tm * const	tmp;
1797 struct tm * (* const	funcp)(const time_t*, long, struct tm*);
1798 const long		offset;
1799 int * const		okayp;
1800 const int		do_norm_secs;
1801 {
1802 	register const struct state *	sp;
1803 	register int			dir;
1804 	register int			i, j;
1805 	register int			saved_seconds;
1806 	register long			li;
1807 	register time_t			lo;
1808 	register time_t			hi;
1809 	long				y;
1810 	time_t				newt;
1811 	time_t				t;
1812 	struct tm			yourtm, mytm;
1813 
1814 	*okayp = FALSE;
1815 	yourtm = *tmp;
1816 	if (do_norm_secs) {
1817 		if (normalize_overflow(&yourtm.tm_min, &yourtm.tm_sec,
1818 			SECSPERMIN))
1819 				return WRONG;
1820 	}
1821 	if (normalize_overflow(&yourtm.tm_hour, &yourtm.tm_min, MINSPERHOUR))
1822 		return WRONG;
1823 	if (normalize_overflow(&yourtm.tm_mday, &yourtm.tm_hour, HOURSPERDAY))
1824 		return WRONG;
1825 	y = yourtm.tm_year;
1826 	if (long_normalize_overflow(&y, &yourtm.tm_mon, MONSPERYEAR))
1827 		return WRONG;
1828 	/*
1829 	** Turn y into an actual year number for now.
1830 	** It is converted back to an offset from TM_YEAR_BASE later.
1831 	*/
1832 	if (long_increment_overflow(&y, TM_YEAR_BASE))
1833 		return WRONG;
1834 	while (yourtm.tm_mday <= 0) {
1835 		if (long_increment_overflow(&y, -1))
1836 			return WRONG;
1837 		li = y + (1 < yourtm.tm_mon);
1838 		yourtm.tm_mday += year_lengths[isleap(li)];
1839 	}
1840 	while (yourtm.tm_mday > DAYSPERLYEAR) {
1841 		li = y + (1 < yourtm.tm_mon);
1842 		yourtm.tm_mday -= year_lengths[isleap(li)];
1843 		if (long_increment_overflow(&y, 1))
1844 			return WRONG;
1845 	}
1846 	for ( ; ; ) {
1847 		i = mon_lengths[isleap(y)][yourtm.tm_mon];
1848 		if (yourtm.tm_mday <= i)
1849 			break;
1850 		yourtm.tm_mday -= i;
1851 		if (++yourtm.tm_mon >= MONSPERYEAR) {
1852 			yourtm.tm_mon = 0;
1853 			if (long_increment_overflow(&y, 1))
1854 				return WRONG;
1855 		}
1856 	}
1857 	if (long_increment_overflow(&y, -TM_YEAR_BASE))
1858 		return WRONG;
1859 	yourtm.tm_year = y;
1860 	if (yourtm.tm_year != y)
1861 		return WRONG;
1862 	if (yourtm.tm_sec >= 0 && yourtm.tm_sec < SECSPERMIN)
1863 		saved_seconds = 0;
1864 	else if (y + TM_YEAR_BASE < EPOCH_YEAR) {
1865 		/*
1866 		** We can't set tm_sec to 0, because that might push the
1867 		** time below the minimum representable time.
1868 		** Set tm_sec to 59 instead.
1869 		** This assumes that the minimum representable time is
1870 		** not in the same minute that a leap second was deleted from,
1871 		** which is a safer assumption than using 58 would be.
1872 		*/
1873 		if (increment_overflow(&yourtm.tm_sec, 1 - SECSPERMIN))
1874 			return WRONG;
1875 		saved_seconds = yourtm.tm_sec;
1876 		yourtm.tm_sec = SECSPERMIN - 1;
1877 	} else {
1878 		saved_seconds = yourtm.tm_sec;
1879 		yourtm.tm_sec = 0;
1880 	}
1881 	/*
1882 	** Do a binary search (this works whatever time_t's type is).
1883 	*/
1884 /* LINTED constant */
1885 	if (!TYPE_SIGNED(time_t)) {
1886 		lo = 0;
1887 		hi = lo - 1;
1888 /* LINTED constant */
1889 	} else if (!TYPE_INTEGRAL(time_t)) {
1890 /* CONSTCOND */
1891 		if (sizeof(time_t) > sizeof(float))
1892 /* LINTED assumed double */
1893 			hi = (time_t) DBL_MAX;
1894 /* LINTED assumed float */
1895 		else	hi = (time_t) FLT_MAX;
1896 		lo = -hi;
1897 	} else {
1898 		lo = 1;
1899 		for (i = 0; i < (int) TYPE_BIT(time_t) - 1; ++i)
1900 			lo *= 2;
1901 		hi = -(lo + 1);
1902 	}
1903 	for ( ; ; ) {
1904 		t = lo / 2 + hi / 2;
1905 		if (t < lo)
1906 			t = lo;
1907 		else if (t > hi)
1908 			t = hi;
1909 		if ((*funcp)(&t, offset, &mytm) == NULL) {
1910 			/*
1911 			** Assume that t is too extreme to be represented in
1912 			** a struct tm; arrange things so that it is less
1913 			** extreme on the next pass.
1914 			*/
1915 			dir = (t > 0) ? 1 : -1;
1916 		} else	dir = tmcomp(&mytm, &yourtm);
1917 		if (dir != 0) {
1918 			if (t == lo) {
1919 				++t;
1920 				if (t <= lo)
1921 					return WRONG;
1922 				++lo;
1923 			} else if (t == hi) {
1924 				--t;
1925 				if (t >= hi)
1926 					return WRONG;
1927 				--hi;
1928 			}
1929 			if (lo > hi)
1930 				return WRONG;
1931 			if (dir > 0)
1932 				hi = t;
1933 			else	lo = t;
1934 			continue;
1935 		}
1936 		if (yourtm.tm_isdst < 0 || mytm.tm_isdst == yourtm.tm_isdst)
1937 			break;
1938 		/*
1939 		** Right time, wrong type.
1940 		** Hunt for right time, right type.
1941 		** It's okay to guess wrong since the guess
1942 		** gets checked.
1943 		*/
1944 		sp = (const struct state *)
1945 			((funcp == localsub) ? lclptr : gmtptr);
1946 #ifdef ALL_STATE
1947 		if (sp == NULL)
1948 			return WRONG;
1949 #endif /* defined ALL_STATE */
1950 		for (i = sp->typecnt - 1; i >= 0; --i) {
1951 			if (sp->ttis[i].tt_isdst != yourtm.tm_isdst)
1952 				continue;
1953 			for (j = sp->typecnt - 1; j >= 0; --j) {
1954 				if (sp->ttis[j].tt_isdst == yourtm.tm_isdst)
1955 					continue;
1956 				newt = t + sp->ttis[j].tt_gmtoff -
1957 					sp->ttis[i].tt_gmtoff;
1958 				if ((*funcp)(&newt, offset, &mytm) == NULL)
1959 					continue;
1960 				if (tmcomp(&mytm, &yourtm) != 0)
1961 					continue;
1962 				if (mytm.tm_isdst != yourtm.tm_isdst)
1963 					continue;
1964 				/*
1965 				** We have a match.
1966 				*/
1967 				t = newt;
1968 				goto label;
1969 			}
1970 		}
1971 		return WRONG;
1972 	}
1973 label:
1974 	newt = t + saved_seconds;
1975 	if ((newt < t) != (saved_seconds < 0))
1976 		return WRONG;
1977 	t = newt;
1978 	if ((*funcp)(&t, offset, tmp))
1979 		*okayp = TRUE;
1980 	return t;
1981 }
1982 
1983 static time_t
1984 time2(tmp, funcp, offset, okayp)
1985 struct tm * const	tmp;
1986 struct tm * (* const	funcp)(const time_t*, long, struct tm*);
1987 const long		offset;
1988 int * const		okayp;
1989 {
1990 	time_t	t;
1991 
1992 	/*
1993 	** First try without normalization of seconds
1994 	** (in case tm_sec contains a value associated with a leap second).
1995 	** If that fails, try with normalization of seconds.
1996 	*/
1997 	t = time2sub(tmp, funcp, offset, okayp, FALSE);
1998 	return *okayp ? t : time2sub(tmp, funcp, offset, okayp, TRUE);
1999 }
2000 
2001 static time_t
2002 time1(tmp, funcp, offset)
2003 struct tm * const	tmp;
2004 struct tm * (* const	funcp)(const time_t *, long, struct tm *);
2005 const long		offset;
2006 {
2007 	register time_t			t;
2008 	register const struct state *	sp;
2009 	register int			samei, otheri;
2010 	register int			sameind, otherind;
2011 	register int			i;
2012 	register int			nseen;
2013 	int				seen[TZ_MAX_TYPES];
2014 	int				types[TZ_MAX_TYPES];
2015 	int				okay;
2016 
2017 	if (tmp->tm_isdst > 1)
2018 		tmp->tm_isdst = 1;
2019 	t = time2(tmp, funcp, offset, &okay);
2020 #ifdef PCTS
2021 	/*
2022 	** PCTS code courtesy Grant Sullivan.
2023 	*/
2024 	if (okay)
2025 		return t;
2026 	if (tmp->tm_isdst < 0)
2027 		tmp->tm_isdst = 0;	/* reset to std and try again */
2028 #endif /* defined PCTS */
2029 #ifndef PCTS
2030 	if (okay || tmp->tm_isdst < 0)
2031 		return t;
2032 #endif /* !defined PCTS */
2033 	/*
2034 	** We're supposed to assume that somebody took a time of one type
2035 	** and did some math on it that yielded a "struct tm" that's bad.
2036 	** We try to divine the type they started from and adjust to the
2037 	** type they need.
2038 	*/
2039 	sp = (const struct state *) ((funcp == localsub) ?  lclptr : gmtptr);
2040 #ifdef ALL_STATE
2041 	if (sp == NULL)
2042 		return WRONG;
2043 #endif /* defined ALL_STATE */
2044 	for (i = 0; i < sp->typecnt; ++i)
2045 		seen[i] = FALSE;
2046 	nseen = 0;
2047 	for (i = sp->timecnt - 1; i >= 0; --i)
2048 		if (!seen[sp->types[i]]) {
2049 			seen[sp->types[i]] = TRUE;
2050 			types[nseen++] = sp->types[i];
2051 		}
2052 	for (sameind = 0; sameind < nseen; ++sameind) {
2053 		samei = types[sameind];
2054 		if (sp->ttis[samei].tt_isdst != tmp->tm_isdst)
2055 			continue;
2056 		for (otherind = 0; otherind < nseen; ++otherind) {
2057 			otheri = types[otherind];
2058 			if (sp->ttis[otheri].tt_isdst == tmp->tm_isdst)
2059 				continue;
2060 			tmp->tm_sec += (int)(sp->ttis[otheri].tt_gmtoff -
2061 					sp->ttis[samei].tt_gmtoff);
2062 			tmp->tm_isdst = !tmp->tm_isdst;
2063 			t = time2(tmp, funcp, offset, &okay);
2064 			if (okay)
2065 				return t;
2066 			tmp->tm_sec -= (int)(sp->ttis[otheri].tt_gmtoff -
2067 					sp->ttis[samei].tt_gmtoff);
2068 			tmp->tm_isdst = !tmp->tm_isdst;
2069 		}
2070 	}
2071 	return WRONG;
2072 }
2073 
2074 time_t
2075 mktime(tmp)
2076 struct tm * const	tmp;
2077 {
2078 	time_t result;
2079 
2080 	rwlock_wrlock(&lcl_lock);
2081 	tzset_unlocked();
2082 	result = time1(tmp, localsub, 0L);
2083 	rwlock_unlock(&lcl_lock);
2084 	return (result);
2085 }
2086 
2087 #ifdef STD_INSPIRED
2088 
2089 time_t
2090 timelocal(tmp)
2091 struct tm * const	tmp;
2092 {
2093 	tmp->tm_isdst = -1;	/* in case it wasn't initialized */
2094 	return mktime(tmp);
2095 }
2096 
2097 time_t
2098 timegm(tmp)
2099 struct tm * const	tmp;
2100 {
2101 	tmp->tm_isdst = 0;
2102 	return time1(tmp, gmtsub, 0L);
2103 }
2104 
2105 time_t
2106 timeoff(tmp, offset)
2107 struct tm * const	tmp;
2108 const long		offset;
2109 {
2110 	tmp->tm_isdst = 0;
2111 	return time1(tmp, gmtsub, offset);
2112 }
2113 
2114 #endif /* defined STD_INSPIRED */
2115 
2116 #ifdef CMUCS
2117 
2118 /*
2119 ** The following is supplied for compatibility with
2120 ** previous versions of the CMUCS runtime library.
2121 */
2122 
2123 long
2124 gtime(tmp)
2125 struct tm * const	tmp;
2126 {
2127 	const time_t	t = mktime(tmp);
2128 
2129 	if (t == WRONG)
2130 		return -1;
2131 	return t;
2132 }
2133 
2134 #endif /* defined CMUCS */
2135 
2136 /*
2137 ** XXX--is the below the right way to conditionalize??
2138 */
2139 
2140 #ifdef STD_INSPIRED
2141 
2142 /*
2143 ** IEEE Std 1003.1-1988 (POSIX) legislates that 536457599
2144 ** shall correspond to "Wed Dec 31 23:59:59 UTC 1986", which
2145 ** is not the case if we are accounting for leap seconds.
2146 ** So, we provide the following conversion routines for use
2147 ** when exchanging timestamps with POSIX conforming systems.
2148 */
2149 
2150 static long
2151 leapcorr(timep)
2152 time_t *	timep;
2153 {
2154 	register struct state *		sp;
2155 	register struct lsinfo *	lp;
2156 	register int			i;
2157 
2158 	sp = lclptr;
2159 	i = sp->leapcnt;
2160 	while (--i >= 0) {
2161 		lp = &sp->lsis[i];
2162 		if (*timep >= lp->ls_trans)
2163 			return lp->ls_corr;
2164 	}
2165 	return 0;
2166 }
2167 
2168 time_t
2169 time2posix(t)
2170 time_t	t;
2171 {
2172 	time_t result;
2173 
2174 	rwlock_wrlock(&lcl_lock);
2175 	tzset_unlocked();
2176 	result = t - leapcorr(&t);
2177 	rwlock_unlock(&lcl_lock);
2178 	return (result);
2179 }
2180 
2181 time_t
2182 posix2time(t)
2183 time_t	t;
2184 {
2185 	time_t	x;
2186 	time_t	y;
2187 
2188 	rwlock_wrlock(&lcl_lock);
2189 	tzset_unlocked();
2190 	/*
2191 	** For a positive leap second hit, the result
2192 	** is not unique. For a negative leap second
2193 	** hit, the corresponding time doesn't exist,
2194 	** so we return an adjacent second.
2195 	*/
2196 	x = t + leapcorr(&t);
2197 	y = x - leapcorr(&x);
2198 	if (y < t) {
2199 		do {
2200 			x++;
2201 			y = x - leapcorr(&x);
2202 		} while (y < t);
2203 		if (t != y) {
2204 			rwlock_unlock(&lcl_lock);
2205 			return x - 1;
2206 		}
2207 	} else if (y > t) {
2208 		do {
2209 			--x;
2210 			y = x - leapcorr(&x);
2211 		} while (y > t);
2212 		if (t != y) {
2213 			rwlock_unlock(&lcl_lock);
2214 			return x + 1;
2215 		}
2216 	}
2217 	rwlock_unlock(&lcl_lock);
2218 	return x;
2219 }
2220 
2221 #endif /* defined STD_INSPIRED */
2222