xref: /netbsd-src/lib/libc/time/localtime.c (revision ba65fde2d7fefa7d39838fa5fa855e62bd606b5e)
1 /*	$NetBSD: localtime.c,v 1.72 2012/10/28 19:02:29 christos Exp $	*/
2 
3 /*
4 ** This file is in the public domain, so clarified as of
5 ** 1996-06-05 by Arthur David Olson.
6 */
7 
8 #include <sys/cdefs.h>
9 #if defined(LIBC_SCCS) && !defined(lint)
10 #if 0
11 static char	elsieid[] = "@(#)localtime.c	8.17";
12 #else
13 __RCSID("$NetBSD: localtime.c,v 1.72 2012/10/28 19:02:29 christos Exp $");
14 #endif
15 #endif /* LIBC_SCCS and not lint */
16 
17 /*
18 ** Leap second handling from Bradley White.
19 ** POSIX-style TZ environment variable handling from Guy Harris.
20 */
21 
22 /*LINTLIBRARY*/
23 
24 #include "namespace.h"
25 #include "private.h"
26 #include "tzfile.h"
27 #include "fcntl.h"
28 #include "reentrant.h"
29 
30 #if defined(__weak_alias)
31 __weak_alias(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,
132 				sizeof gmt), (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 typedef struct tm *(*subfun_t)(const timezone_t sp, const time_t *timep,
149 			       long offset, struct tm *tmp);
150 
151 /*
152 ** Prototypes for static functions.
153 */
154 
155 static long		detzcode(const char * codep);
156 static time_t		detzcode64(const char * codep);
157 static int		differ_by_repeat(time_t t1, time_t t0);
158 static const char *	getzname(const char * strp) __pure;
159 static const char *	getqzname(const char * strp, const int delim) __pure;
160 static const char *	getnum(const char * strp, int * nump, int min,
161 				int max);
162 static const char *	getsecs(const char * strp, long * secsp);
163 static const char *	getoffset(const char * strp, long * offsetp);
164 static const char *	getrule(const char * strp, struct rule * rulep);
165 static void		gmtload(timezone_t sp);
166 static struct tm *	gmtsub(const timezone_t sp, const time_t *timep,
167 				long offset, struct tm * tmp);
168 static struct tm *	localsub(const timezone_t sp, const time_t *timep,
169 				long offset, struct tm *tmp);
170 static int		increment_overflow(int * number, int delta);
171 static int		leaps_thru_end_of(int y) __pure;
172 static int		long_increment_overflow(long * number, int delta);
173 static int		long_normalize_overflow(long * tensptr,
174 				int * unitsptr, int base);
175 static int		normalize_overflow(int * tensptr, int * unitsptr,
176 				int base);
177 static void		settzname(void);
178 static time_t		time1(const timezone_t sp, struct tm * const tmp,
179 				subfun_t funcp, const long offset);
180 static time_t		time2(const timezone_t sp, struct tm * const tmp,
181 				subfun_t funcp,
182 				const long offset, int *const okayp);
183 static time_t		time2sub(const timezone_t sp, struct tm * const tmp,
184 				subfun_t funcp, const long offset,
185 				int *const okayp, const int do_norm_secs);
186 static struct tm *	timesub(const timezone_t sp, const time_t * timep,
187 				long offset, struct tm * tmp);
188 static int		tmcomp(const struct tm * atmp,
189 				const struct tm * btmp);
190 static time_t		transtime(time_t janfirst, int year,
191 				const struct rule * rulep, long offset) __pure;
192 static int		typesequiv(const timezone_t sp, int a, int b);
193 static int		tzload(timezone_t sp, const char * name,
194 				int doextend);
195 static int		tzparse(timezone_t sp, const char * name,
196 				int lastditch);
197 static void		tzset_unlocked(void);
198 static void		tzsetwall_unlocked(void);
199 static long		leapcorr(const timezone_t sp, time_t * timep);
200 
201 static timezone_t lclptr;
202 static timezone_t gmtptr;
203 
204 #ifndef TZ_STRLEN_MAX
205 #define TZ_STRLEN_MAX 255
206 #endif /* !defined TZ_STRLEN_MAX */
207 
208 static char		lcl_TZname[TZ_STRLEN_MAX + 1];
209 static int		lcl_is_set;
210 static int		gmt_is_set;
211 
212 #if !defined(__LIBC12_SOURCE__)
213 
214 __aconst char *		tzname[2] = {
215 	(__aconst char *)__UNCONST(wildabbr),
216 	(__aconst char *)__UNCONST(wildabbr)
217 };
218 
219 #else
220 
221 extern __aconst char *	tzname[2];
222 
223 #endif
224 
225 #ifdef _REENTRANT
226 static rwlock_t lcl_lock = RWLOCK_INITIALIZER;
227 #endif
228 
229 /*
230 ** Section 4.12.3 of X3.159-1989 requires that
231 **	Except for the strftime function, these functions [asctime,
232 **	ctime, gmtime, localtime] return values in one of two static
233 **	objects: a broken-down time structure and an array of char.
234 ** Thanks to Paul Eggert for noting this.
235 */
236 
237 static struct tm	tm;
238 
239 #ifdef USG_COMPAT
240 #if !defined(__LIBC12_SOURCE__)
241 long 			timezone = 0;
242 int			daylight = 0;
243 #else
244 extern int		daylight;
245 extern long		timezone __RENAME(__timezone13);
246 #endif
247 #endif /* defined USG_COMPAT */
248 
249 #ifdef ALTZONE
250 time_t			altzone = 0;
251 #endif /* defined ALTZONE */
252 
253 static long
254 detzcode(const char *const codep)
255 {
256 	long	result;
257 	int	i;
258 
259 	result = (codep[0] & 0x80) ? ~0L : 0;
260 	for (i = 0; i < 4; ++i)
261 		result = (result << 8) | (codep[i] & 0xff);
262 	return result;
263 }
264 
265 static time_t
266 detzcode64(const char *const codep)
267 {
268 	time_t	result;
269 	int	i;
270 
271 	result = (time_t)((codep[0] & 0x80) ? (~(int_fast64_t) 0) : 0);
272 	for (i = 0; i < 8; ++i)
273 		result = result * 256 + (codep[i] & 0xff);
274 	return result;
275 }
276 
277 const char *
278 tzgetname(const timezone_t sp, int isdst)
279 {
280 	int i;
281 	for (i = 0; i < sp->timecnt; ++i) {
282 		const struct ttinfo *const ttisp = &sp->ttis[sp->types[i]];
283 
284 		if (ttisp->tt_isdst == isdst)
285 			return &sp->chars[ttisp->tt_abbrind];
286 	}
287 	return NULL;
288 }
289 
290 static void
291 settzname_z(timezone_t sp)
292 {
293 	int			i;
294 
295 	/*
296 	** Scrub the abbreviations.
297 	** First, replace bogus characters.
298 	*/
299 	for (i = 0; i < sp->charcnt; ++i)
300 		if (strchr(TZ_ABBR_CHAR_SET, sp->chars[i]) == NULL)
301 			sp->chars[i] = TZ_ABBR_ERR_CHAR;
302 	/*
303 	** Second, truncate long abbreviations.
304 	*/
305 	for (i = 0; i < sp->typecnt; ++i) {
306 		const struct ttinfo * const	ttisp = &sp->ttis[i];
307 		char *				cp = &sp->chars[ttisp->tt_abbrind];
308 
309 		if (strlen(cp) > TZ_ABBR_MAX_LEN &&
310 			strcmp(cp, GRANDPARENTED) != 0)
311 				*(cp + TZ_ABBR_MAX_LEN) = '\0';
312 	}
313 }
314 
315 static void
316 settzname(void)
317 {
318 	timezone_t const	sp = lclptr;
319 	int			i;
320 
321 	tzname[0] = (__aconst char *)__UNCONST(wildabbr);
322 	tzname[1] = (__aconst char *)__UNCONST(wildabbr);
323 #ifdef USG_COMPAT
324 	daylight = 0;
325 	timezone = 0;
326 #endif /* defined USG_COMPAT */
327 #ifdef ALTZONE
328 	altzone = 0;
329 #endif /* defined ALTZONE */
330 	if (sp == NULL) {
331 		tzname[0] = tzname[1] = (__aconst char *)__UNCONST(gmt);
332 		return;
333 	}
334 	/*
335 	** And to get the latest zone names into tzname. . .
336 	*/
337 	for (i = 0; i < sp->typecnt; ++i) {
338 		const struct ttinfo * const	ttisp = &sp->ttis[i];
339 
340 		tzname[ttisp->tt_isdst] =
341 			&sp->chars[ttisp->tt_abbrind];
342 #ifdef USG_COMPAT
343 		if (ttisp->tt_isdst)
344 			daylight = 1;
345 		if (!ttisp->tt_isdst)
346 			timezone = -(ttisp->tt_gmtoff);
347 #endif /* defined USG_COMPAT */
348 #ifdef ALTZONE
349 		if (ttisp->tt_isdst)
350 			altzone = -(ttisp->tt_gmtoff);
351 #endif /* defined ALTZONE */
352 	}
353 	settzname_z(sp);
354 }
355 
356 static int
357 differ_by_repeat(const time_t t1, const time_t t0)
358 {
359 	if (TYPE_INTEGRAL(time_t) &&
360 		TYPE_BIT(time_t) - TYPE_SIGNED(time_t) < SECSPERREPEAT_BITS)
361 			return 0;
362 	return (int_fast64_t)t1 - (int_fast64_t)t0 == SECSPERREPEAT;
363 }
364 
365 static int
366 tzload(timezone_t sp, const char *name, const int doextend)
367 {
368 	const char *		p;
369 	int			i;
370 	int			fid;
371 	int			stored;
372 	ssize_t			nread;
373 	typedef union {
374 		struct tzhead	tzhead;
375 		char		buf[2 * sizeof(struct tzhead) +
376 					2 * sizeof *sp +
377 					4 * TZ_MAX_TIMES];
378 	} u_t;
379 	u_t *			up;
380 
381 	up = calloc(1, sizeof *up);
382 	if (up == NULL)
383 		return -1;
384 
385 	sp->goback = sp->goahead = FALSE;
386 	if (name == NULL && (name = TZDEFAULT) == NULL)
387 		goto oops;
388 	{
389 		int	doaccess;
390 		/*
391 		** Section 4.9.1 of the C standard says that
392 		** "FILENAME_MAX expands to an integral constant expression
393 		** that is the size needed for an array of char large enough
394 		** to hold the longest file name string that the implementation
395 		** guarantees can be opened."
396 		*/
397 		char		fullname[FILENAME_MAX + 1];
398 
399 		if (name[0] == ':')
400 			++name;
401 		doaccess = name[0] == '/';
402 		if (!doaccess) {
403 			if ((p = TZDIR) == NULL)
404 				goto oops;
405 			if ((strlen(p) + strlen(name) + 1) >= sizeof fullname)
406 				goto oops;
407 			(void) strcpy(fullname, p);	/* XXX strcpy is safe */
408 			(void) strcat(fullname, "/");	/* XXX strcat is safe */
409 			(void) strcat(fullname, name);	/* XXX strcat is safe */
410 			/*
411 			** Set doaccess if '.' (as in "../") shows up in name.
412 			*/
413 			if (strchr(name, '.') != NULL)
414 				doaccess = TRUE;
415 			name = fullname;
416 		}
417 		if (doaccess && access(name, R_OK) != 0)
418 			goto oops;
419 		/*
420 		 * XXX potential security problem here if user of a set-id
421 		 * program has set TZ (which is passed in as name) here,
422 		 * and uses a race condition trick to defeat the access(2)
423 		 * above.
424 		 */
425 		if ((fid = open(name, OPEN_MODE)) == -1)
426 			goto oops;
427 	}
428 	nread = read(fid, up->buf, sizeof up->buf);
429 	if (close(fid) < 0 || nread <= 0)
430 		goto oops;
431 	for (stored = 4; stored <= 8; stored *= 2) {
432 		int		ttisstdcnt;
433 		int		ttisgmtcnt;
434 
435 		ttisstdcnt = (int) detzcode(up->tzhead.tzh_ttisstdcnt);
436 		ttisgmtcnt = (int) detzcode(up->tzhead.tzh_ttisgmtcnt);
437 		sp->leapcnt = (int) detzcode(up->tzhead.tzh_leapcnt);
438 		sp->timecnt = (int) detzcode(up->tzhead.tzh_timecnt);
439 		sp->typecnt = (int) detzcode(up->tzhead.tzh_typecnt);
440 		sp->charcnt = (int) detzcode(up->tzhead.tzh_charcnt);
441 		p = up->tzhead.tzh_charcnt + sizeof up->tzhead.tzh_charcnt;
442 		if (sp->leapcnt < 0 || sp->leapcnt > TZ_MAX_LEAPS ||
443 			sp->typecnt <= 0 || sp->typecnt > TZ_MAX_TYPES ||
444 			sp->timecnt < 0 || sp->timecnt > TZ_MAX_TIMES ||
445 			sp->charcnt < 0 || sp->charcnt > TZ_MAX_CHARS ||
446 			(ttisstdcnt != sp->typecnt && ttisstdcnt != 0) ||
447 			(ttisgmtcnt != sp->typecnt && ttisgmtcnt != 0))
448 				goto oops;
449 		if (nread - (p - up->buf) <
450 			sp->timecnt * stored +		/* ats */
451 			sp->timecnt +			/* types */
452 			sp->typecnt * 6 +		/* ttinfos */
453 			sp->charcnt +			/* chars */
454 			sp->leapcnt * (stored + 4) +	/* lsinfos */
455 			ttisstdcnt +			/* ttisstds */
456 			ttisgmtcnt)			/* ttisgmts */
457 				goto oops;
458 		for (i = 0; i < sp->timecnt; ++i) {
459 			sp->ats[i] = (time_t)((stored == 4) ?
460 				detzcode(p) : detzcode64(p));
461 			p += stored;
462 		}
463 		for (i = 0; i < sp->timecnt; ++i) {
464 			sp->types[i] = (unsigned char) *p++;
465 			if (sp->types[i] >= sp->typecnt)
466 				goto oops;
467 		}
468 		for (i = 0; i < sp->typecnt; ++i) {
469 			struct ttinfo *	ttisp;
470 
471 			ttisp = &sp->ttis[i];
472 			ttisp->tt_gmtoff = detzcode(p);
473 			p += 4;
474 			ttisp->tt_isdst = (unsigned char) *p++;
475 			if (ttisp->tt_isdst != 0 && ttisp->tt_isdst != 1)
476 				goto oops;
477 			ttisp->tt_abbrind = (unsigned char) *p++;
478 			if (ttisp->tt_abbrind < 0 ||
479 				ttisp->tt_abbrind > sp->charcnt)
480 					goto oops;
481 		}
482 		for (i = 0; i < sp->charcnt; ++i)
483 			sp->chars[i] = *p++;
484 		sp->chars[i] = '\0';	/* ensure '\0' at end */
485 		for (i = 0; i < sp->leapcnt; ++i) {
486 			struct lsinfo *	lsisp;
487 
488 			lsisp = &sp->lsis[i];
489 			lsisp->ls_trans = (time_t)((stored == 4) ?
490 			    detzcode(p) : detzcode64(p));
491 			p += stored;
492 			lsisp->ls_corr = detzcode(p);
493 			p += 4;
494 		}
495 		for (i = 0; i < sp->typecnt; ++i) {
496 			struct ttinfo *	ttisp;
497 
498 			ttisp = &sp->ttis[i];
499 			if (ttisstdcnt == 0)
500 				ttisp->tt_ttisstd = FALSE;
501 			else {
502 				ttisp->tt_ttisstd = *p++;
503 				if (ttisp->tt_ttisstd != TRUE &&
504 					ttisp->tt_ttisstd != FALSE)
505 						goto oops;
506 			}
507 		}
508 		for (i = 0; i < sp->typecnt; ++i) {
509 			struct ttinfo *	ttisp;
510 
511 			ttisp = &sp->ttis[i];
512 			if (ttisgmtcnt == 0)
513 				ttisp->tt_ttisgmt = FALSE;
514 			else {
515 				ttisp->tt_ttisgmt = *p++;
516 				if (ttisp->tt_ttisgmt != TRUE &&
517 					ttisp->tt_ttisgmt != FALSE)
518 						goto oops;
519 			}
520 		}
521 		/*
522 		** Out-of-sort ats should mean we're running on a
523 		** signed time_t system but using a data file with
524 		** unsigned values (or vice versa).
525 		*/
526 		for (i = 0; i < sp->timecnt - 2; ++i)
527 			if (sp->ats[i] > sp->ats[i + 1]) {
528 				++i;
529 				if (TYPE_SIGNED(time_t)) {
530 					/*
531 					** Ignore the end (easy).
532 					*/
533 					sp->timecnt = i;
534 				} else {
535 					/*
536 					** Ignore the beginning (harder).
537 					*/
538 					int	j;
539 
540 					for (j = 0; j + i < sp->timecnt; ++j) {
541 						sp->ats[j] = sp->ats[j + i];
542 						sp->types[j] = sp->types[j + i];
543 					}
544 					sp->timecnt = j;
545 				}
546 				break;
547 			}
548 		/*
549 		** If this is an old file, we're done.
550 		*/
551 		if (up->tzhead.tzh_version[0] == '\0')
552 			break;
553 		nread -= p - up->buf;
554 		for (i = 0; i < nread; ++i)
555 			up->buf[i] = p[i];
556 		/*
557 		** If this is a narrow integer time_t system, we're done.
558 		*/
559 		if (stored >= (int) sizeof(time_t)
560 /* CONSTCOND */
561 				&& TYPE_INTEGRAL(time_t))
562 			break;
563 	}
564 	if (doextend && nread > 2 &&
565 		up->buf[0] == '\n' && up->buf[nread - 1] == '\n' &&
566 		sp->typecnt + 2 <= TZ_MAX_TYPES) {
567 			struct __state ts;
568 			int	result;
569 
570 			up->buf[nread - 1] = '\0';
571 			result = tzparse(&ts, &up->buf[1], FALSE);
572 			if (result == 0 && ts.typecnt == 2 &&
573 				sp->charcnt + ts.charcnt <= TZ_MAX_CHARS) {
574 					for (i = 0; i < 2; ++i)
575 						ts.ttis[i].tt_abbrind +=
576 							sp->charcnt;
577 					for (i = 0; i < ts.charcnt; ++i)
578 						sp->chars[sp->charcnt++] =
579 							ts.chars[i];
580 					i = 0;
581 					while (i < ts.timecnt &&
582 						ts.ats[i] <=
583 						sp->ats[sp->timecnt - 1])
584 							++i;
585 					while (i < ts.timecnt &&
586 					    sp->timecnt < TZ_MAX_TIMES) {
587 						sp->ats[sp->timecnt] =
588 							ts.ats[i];
589 						sp->types[sp->timecnt] =
590 							sp->typecnt +
591 							ts.types[i];
592 						++sp->timecnt;
593 						++i;
594 					}
595 					sp->ttis[sp->typecnt++] = ts.ttis[0];
596 					sp->ttis[sp->typecnt++] = ts.ttis[1];
597 			}
598 	}
599 	if (sp->timecnt > 1) {
600 		for (i = 1; i < sp->timecnt; ++i)
601 			if (typesequiv(sp, sp->types[i], sp->types[0]) &&
602 				differ_by_repeat(sp->ats[i], sp->ats[0])) {
603 					sp->goback = TRUE;
604 					break;
605 				}
606 		for (i = sp->timecnt - 2; i >= 0; --i)
607 			if (typesequiv(sp, sp->types[sp->timecnt - 1],
608 				sp->types[i]) &&
609 				differ_by_repeat(sp->ats[sp->timecnt - 1],
610 				sp->ats[i])) {
611 					sp->goahead = TRUE;
612 					break;
613 		}
614 	}
615 	free(up);
616 	return 0;
617 oops:
618 	free(up);
619 	return -1;
620 }
621 
622 static int
623 typesequiv(const timezone_t sp, const int a, const int b)
624 {
625 	int	result;
626 
627 	if (sp == NULL ||
628 		a < 0 || a >= sp->typecnt ||
629 		b < 0 || b >= sp->typecnt)
630 			result = FALSE;
631 	else {
632 		const struct ttinfo *	ap = &sp->ttis[a];
633 		const struct ttinfo *	bp = &sp->ttis[b];
634 		result = ap->tt_gmtoff == bp->tt_gmtoff &&
635 			ap->tt_isdst == bp->tt_isdst &&
636 			ap->tt_ttisstd == bp->tt_ttisstd &&
637 			ap->tt_ttisgmt == bp->tt_ttisgmt &&
638 			strcmp(&sp->chars[ap->tt_abbrind],
639 			&sp->chars[bp->tt_abbrind]) == 0;
640 	}
641 	return result;
642 }
643 
644 static const int	mon_lengths[2][MONSPERYEAR] = {
645 	{ 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 },
646 	{ 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }
647 };
648 
649 static const int	year_lengths[2] = {
650 	DAYSPERNYEAR, DAYSPERLYEAR
651 };
652 
653 /*
654 ** Given a pointer into a time zone string, scan until a character that is not
655 ** a valid character in a zone name is found. Return a pointer to that
656 ** character.
657 */
658 
659 static const char *
660 getzname(const char *strp)
661 {
662 	char	c;
663 
664 	while ((c = *strp) != '\0' && !is_digit(c) && c != ',' && c != '-' &&
665 		c != '+')
666 			++strp;
667 	return strp;
668 }
669 
670 /*
671 ** Given a pointer into an extended time zone string, scan until the ending
672 ** delimiter of the zone name is located. Return a pointer to the delimiter.
673 **
674 ** As with getzname above, the legal character set is actually quite
675 ** restricted, with other characters producing undefined results.
676 ** We don't do any checking here; checking is done later in common-case code.
677 */
678 
679 static const char *
680 getqzname(const char *strp, const int delim)
681 {
682 	int	c;
683 
684 	while ((c = *strp) != '\0' && c != delim)
685 		++strp;
686 	return strp;
687 }
688 
689 /*
690 ** Given a pointer into a time zone string, extract a number from that string.
691 ** Check that the number is within a specified range; if it is not, return
692 ** NULL.
693 ** Otherwise, return a pointer to the first character not part of the number.
694 */
695 
696 static const char *
697 getnum(const char *strp, int *const nump, const int min, const int max)
698 {
699 	char	c;
700 	int	num;
701 
702 	if (strp == NULL || !is_digit(c = *strp)) {
703 		errno = EINVAL;
704 		return NULL;
705 	}
706 	num = 0;
707 	do {
708 		num = num * 10 + (c - '0');
709 		if (num > max) {
710 			errno = EOVERFLOW;
711 			return NULL;	/* illegal value */
712 		}
713 		c = *++strp;
714 	} while (is_digit(c));
715 	if (num < min) {
716 		errno = EINVAL;
717 		return NULL;		/* illegal value */
718 	}
719 	*nump = num;
720 	return strp;
721 }
722 
723 /*
724 ** Given a pointer into a time zone string, extract a number of seconds,
725 ** in hh[:mm[:ss]] form, from the string.
726 ** If any error occurs, return NULL.
727 ** Otherwise, return a pointer to the first character not part of the number
728 ** of seconds.
729 */
730 
731 static const char *
732 getsecs(const char *strp, long *const secsp)
733 {
734 	int	num;
735 
736 	/*
737 	** `HOURSPERDAY * DAYSPERWEEK - 1' allows quasi-Posix rules like
738 	** "M10.4.6/26", which does not conform to Posix,
739 	** but which specifies the equivalent of
740 	** ``02:00 on the first Sunday on or after 23 Oct''.
741 	*/
742 	strp = getnum(strp, &num, 0, HOURSPERDAY * DAYSPERWEEK - 1);
743 	if (strp == NULL)
744 		return NULL;
745 	*secsp = num * (long) SECSPERHOUR;
746 	if (*strp == ':') {
747 		++strp;
748 		strp = getnum(strp, &num, 0, MINSPERHOUR - 1);
749 		if (strp == NULL)
750 			return NULL;
751 		*secsp += num * SECSPERMIN;
752 		if (*strp == ':') {
753 			++strp;
754 			/* `SECSPERMIN' allows for leap seconds. */
755 			strp = getnum(strp, &num, 0, SECSPERMIN);
756 			if (strp == NULL)
757 				return NULL;
758 			*secsp += num;
759 		}
760 	}
761 	return strp;
762 }
763 
764 /*
765 ** Given a pointer into a time zone string, extract an offset, in
766 ** [+-]hh[:mm[:ss]] form, from the string.
767 ** If any error occurs, return NULL.
768 ** Otherwise, return a pointer to the first character not part of the time.
769 */
770 
771 static const char *
772 getoffset(const char *strp, long *const offsetp)
773 {
774 	int	neg = 0;
775 
776 	if (*strp == '-') {
777 		neg = 1;
778 		++strp;
779 	} else if (*strp == '+')
780 		++strp;
781 	strp = getsecs(strp, offsetp);
782 	if (strp == NULL)
783 		return NULL;		/* illegal time */
784 	if (neg)
785 		*offsetp = -*offsetp;
786 	return strp;
787 }
788 
789 /*
790 ** Given a pointer into a time zone string, extract a rule in the form
791 ** date[/time]. See POSIX section 8 for the format of "date" and "time".
792 ** If a valid rule is not found, return NULL.
793 ** Otherwise, return a pointer to the first character not part of the rule.
794 */
795 
796 static const char *
797 getrule(const char *strp, struct rule *const rulep)
798 {
799 	if (*strp == 'J') {
800 		/*
801 		** Julian day.
802 		*/
803 		rulep->r_type = JULIAN_DAY;
804 		++strp;
805 		strp = getnum(strp, &rulep->r_day, 1, DAYSPERNYEAR);
806 	} else if (*strp == 'M') {
807 		/*
808 		** Month, week, day.
809 		*/
810 		rulep->r_type = MONTH_NTH_DAY_OF_WEEK;
811 		++strp;
812 		strp = getnum(strp, &rulep->r_mon, 1, MONSPERYEAR);
813 		if (strp == NULL)
814 			return NULL;
815 		if (*strp++ != '.')
816 			return NULL;
817 		strp = getnum(strp, &rulep->r_week, 1, 5);
818 		if (strp == NULL)
819 			return NULL;
820 		if (*strp++ != '.')
821 			return NULL;
822 		strp = getnum(strp, &rulep->r_day, 0, DAYSPERWEEK - 1);
823 	} else if (is_digit(*strp)) {
824 		/*
825 		** Day of year.
826 		*/
827 		rulep->r_type = DAY_OF_YEAR;
828 		strp = getnum(strp, &rulep->r_day, 0, DAYSPERLYEAR - 1);
829 	} else	return NULL;		/* invalid format */
830 	if (strp == NULL)
831 		return NULL;
832 	if (*strp == '/') {
833 		/*
834 		** Time specified.
835 		*/
836 		++strp;
837 		strp = getsecs(strp, &rulep->r_time);
838 	} else	rulep->r_time = 2 * SECSPERHOUR;	/* default = 2:00:00 */
839 	return strp;
840 }
841 
842 /*
843 ** Given the Epoch-relative time of January 1, 00:00:00 UTC, in a year, the
844 ** year, a rule, and the offset from UTC at the time that rule takes effect,
845 ** calculate the Epoch-relative time that rule takes effect.
846 */
847 
848 static time_t
849 transtime(const time_t janfirst, const int year, const struct rule *const rulep,
850     const long offset)
851 {
852 	int	leapyear;
853 	time_t	value;
854 	int	i;
855 	int		d, m1, yy0, yy1, yy2, dow;
856 
857 	INITIALIZE(value);
858 	leapyear = isleap(year);
859 	switch (rulep->r_type) {
860 
861 	case JULIAN_DAY:
862 		/*
863 		** Jn - Julian day, 1 == January 1, 60 == March 1 even in leap
864 		** years.
865 		** In non-leap years, or if the day number is 59 or less, just
866 		** add SECSPERDAY times the day number-1 to the time of
867 		** January 1, midnight, to get the day.
868 		*/
869 		value = (time_t)(janfirst + (rulep->r_day - 1) * SECSPERDAY);
870 		if (leapyear && rulep->r_day >= 60)
871 			value += SECSPERDAY;
872 		break;
873 
874 	case DAY_OF_YEAR:
875 		/*
876 		** n - day of year.
877 		** Just add SECSPERDAY times the day number to the time of
878 		** January 1, midnight, to get the day.
879 		*/
880 		value = (time_t)(janfirst + rulep->r_day * SECSPERDAY);
881 		break;
882 
883 	case MONTH_NTH_DAY_OF_WEEK:
884 		/*
885 		** Mm.n.d - nth "dth day" of month m.
886 		*/
887 		value = janfirst;
888 		for (i = 0; i < rulep->r_mon - 1; ++i)
889 			value += (time_t)(mon_lengths[leapyear][i] * SECSPERDAY);
890 
891 		/*
892 		** Use Zeller's Congruence to get day-of-week of first day of
893 		** month.
894 		*/
895 		m1 = (rulep->r_mon + 9) % 12 + 1;
896 		yy0 = (rulep->r_mon <= 2) ? (year - 1) : year;
897 		yy1 = yy0 / 100;
898 		yy2 = yy0 % 100;
899 		dow = ((26 * m1 - 2) / 10 +
900 			1 + yy2 + yy2 / 4 + yy1 / 4 - 2 * yy1) % 7;
901 		if (dow < 0)
902 			dow += DAYSPERWEEK;
903 
904 		/*
905 		** "dow" is the day-of-week of the first day of the month. Get
906 		** the day-of-month (zero-origin) of the first "dow" day of the
907 		** month.
908 		*/
909 		d = rulep->r_day - dow;
910 		if (d < 0)
911 			d += DAYSPERWEEK;
912 		for (i = 1; i < rulep->r_week; ++i) {
913 			if (d + DAYSPERWEEK >=
914 				mon_lengths[leapyear][rulep->r_mon - 1])
915 					break;
916 			d += DAYSPERWEEK;
917 		}
918 
919 		/*
920 		** "d" is the day-of-month (zero-origin) of the day we want.
921 		*/
922 		value += (time_t)(d * SECSPERDAY);
923 		break;
924 	}
925 
926 	/*
927 	** "value" is the Epoch-relative time of 00:00:00 UTC on the day in
928 	** question. To get the Epoch-relative time of the specified local
929 	** time on that day, add the transition time and the current offset
930 	** from UTC.
931 	*/
932 	return (time_t)(value + rulep->r_time + offset);
933 }
934 
935 /*
936 ** Given a POSIX section 8-style TZ string, fill in the rule tables as
937 ** appropriate.
938 */
939 
940 static int
941 tzparse(timezone_t sp, const char *name, const int lastditch)
942 {
943 	const char *			stdname;
944 	const char *			dstname;
945 	size_t				stdlen;
946 	size_t				dstlen;
947 	long				stdoffset;
948 	long				dstoffset;
949 	time_t *		atp;
950 	unsigned char *	typep;
951 	char *			cp;
952 	int			load_result;
953 
954 	INITIALIZE(dstname);
955 	stdname = name;
956 	if (lastditch) {
957 		stdlen = strlen(name);	/* length of standard zone name */
958 		name += stdlen;
959 		if (stdlen >= sizeof sp->chars)
960 			stdlen = (sizeof sp->chars) - 1;
961 		stdoffset = 0;
962 	} else {
963 		if (*name == '<') {
964 			name++;
965 			stdname = name;
966 			name = getqzname(name, '>');
967 			if (*name != '>')
968 				return (-1);
969 			stdlen = name - stdname;
970 			name++;
971 		} else {
972 			name = getzname(name);
973 			stdlen = name - stdname;
974 		}
975 		if (*name == '\0')
976 			return -1;
977 		name = getoffset(name, &stdoffset);
978 		if (name == NULL)
979 			return -1;
980 	}
981 	load_result = tzload(sp, TZDEFRULES, FALSE);
982 	if (load_result != 0)
983 		sp->leapcnt = 0;		/* so, we're off a little */
984 	if (*name != '\0') {
985 		if (*name == '<') {
986 			dstname = ++name;
987 			name = getqzname(name, '>');
988 			if (*name != '>')
989 				return -1;
990 			dstlen = name - dstname;
991 			name++;
992 		} else {
993 			dstname = name;
994 			name = getzname(name);
995 			dstlen = name - dstname; /* length of DST zone name */
996 		}
997 		if (*name != '\0' && *name != ',' && *name != ';') {
998 			name = getoffset(name, &dstoffset);
999 			if (name == NULL)
1000 				return -1;
1001 		} else	dstoffset = stdoffset - SECSPERHOUR;
1002 		if (*name == '\0' && load_result != 0)
1003 			name = TZDEFRULESTRING;
1004 		if (*name == ',' || *name == ';') {
1005 			struct rule	start;
1006 			struct rule	end;
1007 			int	year;
1008 			time_t	janfirst;
1009 			time_t		starttime;
1010 			time_t		endtime;
1011 
1012 			++name;
1013 			if ((name = getrule(name, &start)) == NULL)
1014 				return -1;
1015 			if (*name++ != ',')
1016 				return -1;
1017 			if ((name = getrule(name, &end)) == NULL)
1018 				return -1;
1019 			if (*name != '\0')
1020 				return -1;
1021 			sp->typecnt = 2;	/* standard time and DST */
1022 			/*
1023 			** Two transitions per year, from EPOCH_YEAR forward.
1024 			*/
1025 			memset(sp->ttis, 0, sizeof(sp->ttis));
1026 			sp->ttis[0].tt_gmtoff = -dstoffset;
1027 			sp->ttis[0].tt_isdst = 1;
1028 			sp->ttis[0].tt_abbrind = (int)(stdlen + 1);
1029 			sp->ttis[1].tt_gmtoff = -stdoffset;
1030 			sp->ttis[1].tt_isdst = 0;
1031 			sp->ttis[1].tt_abbrind = 0;
1032 			atp = sp->ats;
1033 			typep = sp->types;
1034 			janfirst = 0;
1035 			sp->timecnt = 0;
1036 			for (year = EPOCH_YEAR;
1037 			    sp->timecnt + 2 <= TZ_MAX_TIMES;
1038 			    ++year) {
1039 			    	time_t	newfirst;
1040 
1041 				starttime = transtime(janfirst, year, &start,
1042 					stdoffset);
1043 				endtime = transtime(janfirst, year, &end,
1044 					dstoffset);
1045 				if (starttime > endtime) {
1046 					*atp++ = endtime;
1047 					*typep++ = 1;	/* DST ends */
1048 					*atp++ = starttime;
1049 					*typep++ = 0;	/* DST begins */
1050 				} else {
1051 					*atp++ = starttime;
1052 					*typep++ = 0;	/* DST begins */
1053 					*atp++ = endtime;
1054 					*typep++ = 1;	/* DST ends */
1055 				}
1056 				sp->timecnt += 2;
1057 				newfirst = janfirst;
1058 				newfirst += (time_t)
1059 				    (year_lengths[isleap(year)] * SECSPERDAY);
1060 				if (newfirst <= janfirst)
1061 					break;
1062 				janfirst = newfirst;
1063 			}
1064 		} else {
1065 			long	theirstdoffset;
1066 			long	theirdstoffset;
1067 			long	theiroffset;
1068 			int	isdst;
1069 			int	i;
1070 			int	j;
1071 
1072 			if (*name != '\0')
1073 				return -1;
1074 			/*
1075 			** Initial values of theirstdoffset and theirdstoffset.
1076 			*/
1077 			theirstdoffset = 0;
1078 			for (i = 0; i < sp->timecnt; ++i) {
1079 				j = sp->types[i];
1080 				if (!sp->ttis[j].tt_isdst) {
1081 					theirstdoffset =
1082 						-sp->ttis[j].tt_gmtoff;
1083 					break;
1084 				}
1085 			}
1086 			theirdstoffset = 0;
1087 			for (i = 0; i < sp->timecnt; ++i) {
1088 				j = sp->types[i];
1089 				if (sp->ttis[j].tt_isdst) {
1090 					theirdstoffset =
1091 						-sp->ttis[j].tt_gmtoff;
1092 					break;
1093 				}
1094 			}
1095 			/*
1096 			** Initially we're assumed to be in standard time.
1097 			*/
1098 			isdst = FALSE;
1099 			theiroffset = theirstdoffset;
1100 			/*
1101 			** Now juggle transition times and types
1102 			** tracking offsets as you do.
1103 			*/
1104 			for (i = 0; i < sp->timecnt; ++i) {
1105 				j = sp->types[i];
1106 				sp->types[i] = sp->ttis[j].tt_isdst;
1107 				if (sp->ttis[j].tt_ttisgmt) {
1108 					/* No adjustment to transition time */
1109 				} else {
1110 					/*
1111 					** If summer time is in effect, and the
1112 					** transition time was not specified as
1113 					** standard time, add the summer time
1114 					** offset to the transition time;
1115 					** otherwise, add the standard time
1116 					** offset to the transition time.
1117 					*/
1118 					/*
1119 					** Transitions from DST to DDST
1120 					** will effectively disappear since
1121 					** POSIX provides for only one DST
1122 					** offset.
1123 					*/
1124 					if (isdst && !sp->ttis[j].tt_ttisstd) {
1125 						sp->ats[i] += (time_t)
1126 						    (dstoffset - theirdstoffset);
1127 					} else {
1128 						sp->ats[i] += (time_t)
1129 						    (stdoffset - theirstdoffset);
1130 					}
1131 				}
1132 				theiroffset = -sp->ttis[j].tt_gmtoff;
1133 				if (!sp->ttis[j].tt_isdst)
1134 					theirstdoffset = theiroffset;
1135 				else	theirdstoffset = theiroffset;
1136 			}
1137 			/*
1138 			** Finally, fill in ttis.
1139 			** ttisstd and ttisgmt need not be handled
1140 			*/
1141 			memset(sp->ttis, 0, sizeof(sp->ttis));
1142 			sp->ttis[0].tt_gmtoff = -stdoffset;
1143 			sp->ttis[0].tt_isdst = FALSE;
1144 			sp->ttis[0].tt_abbrind = 0;
1145 			sp->ttis[1].tt_gmtoff = -dstoffset;
1146 			sp->ttis[1].tt_isdst = TRUE;
1147 			sp->ttis[1].tt_abbrind = (int)(stdlen + 1);
1148 			sp->typecnt = 2;
1149 		}
1150 	} else {
1151 		dstlen = 0;
1152 		sp->typecnt = 1;		/* only standard time */
1153 		sp->timecnt = 0;
1154 		memset(sp->ttis, 0, sizeof(sp->ttis));
1155 		sp->ttis[0].tt_gmtoff = -stdoffset;
1156 		sp->ttis[0].tt_isdst = 0;
1157 		sp->ttis[0].tt_abbrind = 0;
1158 	}
1159 	sp->charcnt = (int)(stdlen + 1);
1160 	if (dstlen != 0)
1161 		sp->charcnt += (int)(dstlen + 1);
1162 	if ((size_t) sp->charcnt > sizeof sp->chars)
1163 		return -1;
1164 	cp = sp->chars;
1165 	(void) strncpy(cp, stdname, stdlen);
1166 	cp += stdlen;
1167 	*cp++ = '\0';
1168 	if (dstlen != 0) {
1169 		(void) strncpy(cp, dstname, dstlen);
1170 		*(cp + dstlen) = '\0';
1171 	}
1172 	return 0;
1173 }
1174 
1175 static void
1176 gmtload(timezone_t sp)
1177 {
1178 	if (tzload(sp, gmt, TRUE) != 0)
1179 		(void) tzparse(sp, gmt, TRUE);
1180 }
1181 
1182 timezone_t
1183 tzalloc(const char *name)
1184 {
1185 	timezone_t sp = calloc(1, sizeof *sp);
1186 	if (sp == NULL)
1187 		return NULL;
1188 	if (tzload(sp, name, TRUE) != 0) {
1189 		free(sp);
1190 		return NULL;
1191 	}
1192 	settzname_z(sp);
1193 	return sp;
1194 }
1195 
1196 void
1197 tzfree(const timezone_t sp)
1198 {
1199 	free(sp);
1200 }
1201 
1202 static void
1203 tzsetwall_unlocked(void)
1204 {
1205 	if (lcl_is_set < 0)
1206 		return;
1207 	lcl_is_set = -1;
1208 
1209 	if (lclptr == NULL) {
1210 		int saveerrno = errno;
1211 		lclptr = calloc(1, sizeof *lclptr);
1212 		errno = saveerrno;
1213 		if (lclptr == NULL) {
1214 			settzname();	/* all we can do */
1215 			return;
1216 		}
1217 	}
1218 	if (tzload(lclptr, NULL, TRUE) != 0)
1219 		gmtload(lclptr);
1220 	settzname();
1221 }
1222 
1223 #ifndef STD_INSPIRED
1224 /*
1225 ** A non-static declaration of tzsetwall in a system header file
1226 ** may cause a warning about this upcoming static declaration...
1227 */
1228 static
1229 #endif /* !defined STD_INSPIRED */
1230 void
1231 tzsetwall(void)
1232 {
1233 	rwlock_wrlock(&lcl_lock);
1234 	tzsetwall_unlocked();
1235 	rwlock_unlock(&lcl_lock);
1236 }
1237 
1238 #ifndef STD_INSPIRED
1239 /*
1240 ** A non-static declaration of tzsetwall in a system header file
1241 ** may cause a warning about this upcoming static declaration...
1242 */
1243 static
1244 #endif /* !defined STD_INSPIRED */
1245 void
1246 tzset_unlocked(void)
1247 {
1248 	const char *	name;
1249 
1250 	name = getenv("TZ");
1251 	if (name == NULL) {
1252 		tzsetwall_unlocked();
1253 		return;
1254 	}
1255 
1256 	if (lcl_is_set > 0 && strcmp(lcl_TZname, name) == 0)
1257 		return;
1258 	lcl_is_set = strlen(name) < sizeof lcl_TZname;
1259 	if (lcl_is_set)
1260 		(void)strlcpy(lcl_TZname, name, sizeof(lcl_TZname));
1261 
1262 	if (lclptr == NULL) {
1263 		int saveerrno = errno;
1264 		lclptr = calloc(1, sizeof *lclptr);
1265 		errno = saveerrno;
1266 		if (lclptr == NULL) {
1267 			settzname();	/* all we can do */
1268 			return;
1269 		}
1270 	}
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(lclptr, name, TRUE) != 0)
1283 		if (name[0] == ':' || tzparse(lclptr, name, 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(const timezone_t sp, const time_t * const timep, const long offset,
1308     struct tm *const tmp)
1309 {
1310 	const struct ttinfo *	ttisp;
1311 	int			i;
1312 	struct tm *		result;
1313 	const time_t			t = *timep;
1314 
1315 	if ((sp->goback && t < sp->ats[0]) ||
1316 		(sp->goahead && t > sp->ats[sp->timecnt - 1])) {
1317 			time_t			newt = t;
1318 			time_t		seconds;
1319 			time_t		tcycles;
1320 			int_fast64_t	icycles;
1321 
1322 			if (t < sp->ats[0])
1323 				seconds = sp->ats[0] - t;
1324 			else	seconds = t - sp->ats[sp->timecnt - 1];
1325 			--seconds;
1326 			tcycles = (time_t)
1327 			    (seconds / YEARSPERREPEAT / AVGSECSPERYEAR);
1328 			++tcycles;
1329 			icycles = tcycles;
1330 			if (tcycles - icycles >= 1 || icycles - tcycles >= 1)
1331 				return NULL;
1332 			seconds = (time_t) icycles;
1333 			seconds *= YEARSPERREPEAT;
1334 			seconds *= AVGSECSPERYEAR;
1335 			if (t < sp->ats[0])
1336 				newt += seconds;
1337 			else	newt -= seconds;
1338 			if (newt < sp->ats[0] ||
1339 				newt > sp->ats[sp->timecnt - 1])
1340 					return NULL;	/* "cannot happen" */
1341 			result = localsub(sp, &newt, offset, tmp);
1342 			if (result == tmp) {
1343 				time_t	newy;
1344 
1345 				newy = tmp->tm_year;
1346 				if (t < sp->ats[0])
1347 					newy -= (time_t)icycles * YEARSPERREPEAT;
1348 				else	newy += (time_t)icycles * YEARSPERREPEAT;
1349 				tmp->tm_year = (int)newy;
1350 				if (tmp->tm_year != newy)
1351 					return NULL;
1352 			}
1353 			return result;
1354 	}
1355 	if (sp->timecnt == 0 || t < sp->ats[0]) {
1356 		i = 0;
1357 		while (sp->ttis[i].tt_isdst)
1358 			if (++i >= sp->typecnt) {
1359 				i = 0;
1360 				break;
1361 			}
1362 	} else {
1363 		int	lo = 1;
1364 		int	hi = sp->timecnt;
1365 
1366 		while (lo < hi) {
1367 			int	mid = (lo + hi) / 2;
1368 
1369 			if (t < sp->ats[mid])
1370 				hi = mid;
1371 			else	lo = mid + 1;
1372 		}
1373 		i = (int) sp->types[lo - 1];
1374 	}
1375 	ttisp = &sp->ttis[i];
1376 	/*
1377 	** To get (wrong) behavior that's compatible with System V Release 2.0
1378 	** you'd replace the statement below with
1379 	**	t += ttisp->tt_gmtoff;
1380 	**	timesub(&t, 0L, sp, tmp);
1381 	*/
1382 	result = timesub(sp, &t, ttisp->tt_gmtoff, tmp);
1383 	tmp->tm_isdst = ttisp->tt_isdst;
1384 	if (sp == lclptr)
1385 		tzname[tmp->tm_isdst] = &sp->chars[ttisp->tt_abbrind];
1386 #ifdef TM_ZONE
1387 	tmp->TM_ZONE = &sp->chars[ttisp->tt_abbrind];
1388 #endif /* defined TM_ZONE */
1389 	return result;
1390 }
1391 
1392 /*
1393 ** Re-entrant version of localtime.
1394 */
1395 
1396 struct tm *
1397 localtime_r(const time_t * __restrict timep, struct tm *tmp)
1398 {
1399 	rwlock_rdlock(&lcl_lock);
1400 	tzset_unlocked();
1401 	tmp = localtime_rz(lclptr, timep, tmp);
1402 	rwlock_unlock(&lcl_lock);
1403 	return tmp;
1404 }
1405 
1406 struct tm *
1407 localtime(const time_t *const timep)
1408 {
1409 	return localtime_r(timep, &tm);
1410 }
1411 
1412 struct tm *
1413 localtime_rz(const timezone_t sp, const time_t * __restrict timep, struct tm *tmp)
1414 {
1415 	if (sp == NULL)
1416 		tmp = gmtsub(NULL, timep, 0L, tmp);
1417 	else
1418 		tmp = localsub(sp, timep, 0L, tmp);
1419 	if (tmp == NULL)
1420 		errno = EOVERFLOW;
1421 	return tmp;
1422 }
1423 
1424 /*
1425 ** gmtsub is to gmtime as localsub is to localtime.
1426 */
1427 
1428 static struct tm *
1429 gmtsub(const timezone_t sp, const time_t *const timep, const long offset,
1430     struct tm *const tmp)
1431 {
1432 	struct tm *	result;
1433 #ifdef _REENTRANT
1434 	static mutex_t gmt_mutex = MUTEX_INITIALIZER;
1435 #endif
1436 
1437 	mutex_lock(&gmt_mutex);
1438 	if (!gmt_is_set) {
1439 		int saveerrno;
1440 		gmt_is_set = TRUE;
1441 		saveerrno = errno;
1442 		gmtptr = calloc(1, sizeof *gmtptr);
1443 		errno = saveerrno;
1444 		if (gmtptr != NULL)
1445 			gmtload(gmtptr);
1446 	}
1447 	mutex_unlock(&gmt_mutex);
1448 	result = timesub(gmtptr, timep, offset, tmp);
1449 #ifdef TM_ZONE
1450 	/*
1451 	** Could get fancy here and deliver something such as
1452 	** "UTC+xxxx" or "UTC-xxxx" if offset is non-zero,
1453 	** but this is no time for a treasure hunt.
1454 	*/
1455 	if (offset != 0)
1456 		tmp->TM_ZONE = (__aconst char *)__UNCONST(wildabbr);
1457 	else {
1458 		if (gmtptr == NULL)
1459 			tmp->TM_ZONE = (__aconst char *)__UNCONST(gmt);
1460 		else	tmp->TM_ZONE = gmtptr->chars;
1461 	}
1462 #endif /* defined TM_ZONE */
1463 	return result;
1464 }
1465 
1466 struct tm *
1467 gmtime(const time_t *const timep)
1468 {
1469 	struct tm *tmp = gmtsub(NULL, timep, 0L, &tm);
1470 
1471 	if (tmp == NULL)
1472 		errno = EOVERFLOW;
1473 
1474 	return tmp;
1475 }
1476 
1477 /*
1478 ** Re-entrant version of gmtime.
1479 */
1480 
1481 struct tm *
1482 gmtime_r(const time_t * const timep, struct tm *tmp)
1483 {
1484 	tmp = gmtsub(NULL, timep, 0L, tmp);
1485 
1486 	if (tmp == NULL)
1487 		errno = EOVERFLOW;
1488 
1489 	return tmp;
1490 }
1491 
1492 #ifdef STD_INSPIRED
1493 
1494 struct tm *
1495 offtime(const time_t *const timep, long offset)
1496 {
1497 	struct tm *tmp = gmtsub(NULL, timep, offset, &tm);
1498 
1499 	if (tmp == NULL)
1500 		errno = EOVERFLOW;
1501 
1502 	return tmp;
1503 }
1504 
1505 struct tm *
1506 offtime_r(const time_t *timep, long offset, struct tm *tmp)
1507 {
1508 	tmp = gmtsub(NULL, timep, offset, tmp);
1509 
1510 	if (tmp == NULL)
1511 		errno = EOVERFLOW;
1512 
1513 	return tmp;
1514 }
1515 
1516 #endif /* defined STD_INSPIRED */
1517 
1518 /*
1519 ** Return the number of leap years through the end of the given year
1520 ** where, to make the math easy, the answer for year zero is defined as zero.
1521 */
1522 
1523 static int
1524 leaps_thru_end_of(const int y)
1525 {
1526 	return (y >= 0) ? (y / 4 - y / 100 + y / 400) :
1527 		-(leaps_thru_end_of(-(y + 1)) + 1);
1528 }
1529 
1530 static struct tm *
1531 timesub(const timezone_t sp, const time_t *const timep, const long offset,
1532     struct tm *const tmp)
1533 {
1534 	const struct lsinfo *	lp;
1535 	time_t			tdays;
1536 	int			idays;	/* unsigned would be so 2003 */
1537 	long			rem;
1538 	int			y;
1539 	const int *		ip;
1540 	long			corr;
1541 	int			hit;
1542 	int			i;
1543 
1544 	corr = 0;
1545 	hit = 0;
1546 	i = (sp == NULL) ? 0 : sp->leapcnt;
1547 	while (--i >= 0) {
1548 		lp = &sp->lsis[i];
1549 		if (*timep >= lp->ls_trans) {
1550 			if (*timep == lp->ls_trans) {
1551 				hit = ((i == 0 && lp->ls_corr > 0) ||
1552 					lp->ls_corr > sp->lsis[i - 1].ls_corr);
1553 				if (hit)
1554 					while (i > 0 &&
1555 						sp->lsis[i].ls_trans ==
1556 						sp->lsis[i - 1].ls_trans + 1 &&
1557 						sp->lsis[i].ls_corr ==
1558 						sp->lsis[i - 1].ls_corr + 1) {
1559 							++hit;
1560 							--i;
1561 					}
1562 			}
1563 			corr = lp->ls_corr;
1564 			break;
1565 		}
1566 	}
1567 	y = EPOCH_YEAR;
1568 	tdays = (time_t)(*timep / SECSPERDAY);
1569 	rem = (long) (*timep - tdays * SECSPERDAY);
1570 	while (tdays < 0 || tdays >= year_lengths[isleap(y)]) {
1571 		int		newy;
1572 		time_t	tdelta;
1573 		int	idelta;
1574 		int	leapdays;
1575 
1576 		tdelta = tdays / DAYSPERLYEAR;
1577 		idelta = (int) tdelta;
1578 		if (tdelta - idelta >= 1 || idelta - tdelta >= 1)
1579 			return NULL;
1580 		if (idelta == 0)
1581 			idelta = (tdays < 0) ? -1 : 1;
1582 		newy = y;
1583 		if (increment_overflow(&newy, idelta))
1584 			return NULL;
1585 		leapdays = leaps_thru_end_of(newy - 1) -
1586 			leaps_thru_end_of(y - 1);
1587 		tdays -= ((time_t) newy - y) * DAYSPERNYEAR;
1588 		tdays -= leapdays;
1589 		y = newy;
1590 	}
1591 	{
1592 		long	seconds;
1593 
1594 		seconds = tdays * SECSPERDAY + 0.5;
1595 		tdays = (time_t)(seconds / SECSPERDAY);
1596 		rem += (long) (seconds - tdays * SECSPERDAY);
1597 	}
1598 	/*
1599 	** Given the range, we can now fearlessly cast...
1600 	*/
1601 	idays = (int) tdays;
1602 	rem += offset - corr;
1603 	while (rem < 0) {
1604 		rem += SECSPERDAY;
1605 		--idays;
1606 	}
1607 	while (rem >= SECSPERDAY) {
1608 		rem -= SECSPERDAY;
1609 		++idays;
1610 	}
1611 	while (idays < 0) {
1612 		if (increment_overflow(&y, -1))
1613 			return NULL;
1614 		idays += year_lengths[isleap(y)];
1615 	}
1616 	while (idays >= year_lengths[isleap(y)]) {
1617 		idays -= year_lengths[isleap(y)];
1618 		if (increment_overflow(&y, 1))
1619 			return NULL;
1620 	}
1621 	tmp->tm_year = y;
1622 	if (increment_overflow(&tmp->tm_year, -TM_YEAR_BASE))
1623 		return NULL;
1624 	tmp->tm_yday = idays;
1625 	/*
1626 	** The "extra" mods below avoid overflow problems.
1627 	*/
1628 	tmp->tm_wday = EPOCH_WDAY +
1629 		((y - EPOCH_YEAR) % DAYSPERWEEK) *
1630 		(DAYSPERNYEAR % DAYSPERWEEK) +
1631 		leaps_thru_end_of(y - 1) -
1632 		leaps_thru_end_of(EPOCH_YEAR - 1) +
1633 		idays;
1634 	tmp->tm_wday %= DAYSPERWEEK;
1635 	if (tmp->tm_wday < 0)
1636 		tmp->tm_wday += DAYSPERWEEK;
1637 	tmp->tm_hour = (int) (rem / SECSPERHOUR);
1638 	rem %= SECSPERHOUR;
1639 	tmp->tm_min = (int) (rem / SECSPERMIN);
1640 	/*
1641 	** A positive leap second requires a special
1642 	** representation. This uses "... ??:59:60" et seq.
1643 	*/
1644 	tmp->tm_sec = (int) (rem % SECSPERMIN) + hit;
1645 	ip = mon_lengths[isleap(y)];
1646 	for (tmp->tm_mon = 0; idays >= ip[tmp->tm_mon]; ++(tmp->tm_mon))
1647 		idays -= ip[tmp->tm_mon];
1648 	tmp->tm_mday = (int) (idays + 1);
1649 	tmp->tm_isdst = 0;
1650 #ifdef TM_GMTOFF
1651 	tmp->TM_GMTOFF = offset;
1652 #endif /* defined TM_GMTOFF */
1653 	return tmp;
1654 }
1655 
1656 char *
1657 ctime(const time_t *const timep)
1658 {
1659 /*
1660 ** Section 4.12.3.2 of X3.159-1989 requires that
1661 **	The ctime function converts the calendar time pointed to by timer
1662 **	to local time in the form of a string. It is equivalent to
1663 **		asctime(localtime(timer))
1664 */
1665 	struct tm *rtm = localtime(timep);
1666 	if (rtm == NULL)
1667 		return NULL;
1668 	return asctime(rtm);
1669 }
1670 
1671 char *
1672 ctime_r(const time_t *const timep, char *buf)
1673 {
1674 	struct tm	mytm, *rtm;
1675 
1676 	rtm = localtime_r(timep, &mytm);
1677 	if (rtm == NULL)
1678 		return NULL;
1679 	return asctime_r(rtm, buf);
1680 }
1681 
1682 char *
1683 ctime_rz(const timezone_t sp, const time_t * timep, char *buf)
1684 {
1685 	struct tm	mytm, *rtm;
1686 
1687 	rtm = localtime_rz(sp, timep, &mytm);
1688 	if (rtm == NULL)
1689 		return NULL;
1690 	return asctime_r(rtm, buf);
1691 }
1692 
1693 /*
1694 ** Adapted from code provided by Robert Elz, who writes:
1695 **	The "best" way to do mktime I think is based on an idea of Bob
1696 **	Kridle's (so its said...) from a long time ago.
1697 **	It does a binary search of the time_t space. Since time_t's are
1698 **	just 32 bits, its a max of 32 iterations (even at 64 bits it
1699 **	would still be very reasonable).
1700 */
1701 
1702 #ifndef WRONG
1703 #define WRONG	((time_t)-1)
1704 #endif /* !defined WRONG */
1705 
1706 /*
1707 ** Simplified normalize logic courtesy Paul Eggert.
1708 */
1709 
1710 static int
1711 increment_overflow(int *const ip, int j)
1712 {
1713 	int	i = *ip;
1714 
1715 	/*
1716 	** If i >= 0 there can only be overflow if i + j > INT_MAX
1717 	** or if j > INT_MAX - i; given i >= 0, INT_MAX - i cannot overflow.
1718 	** If i < 0 there can only be overflow if i + j < INT_MIN
1719 	** or if j < INT_MIN - i; given i < 0, INT_MIN - i cannot overflow.
1720 	*/
1721 	if ((i >= 0) ? (j > INT_MAX - i) : (j < INT_MIN - i))
1722 		return TRUE;
1723 	*ip += j;
1724 	return FALSE;
1725 }
1726 
1727 static int
1728 long_increment_overflow(long *const lp, int m)
1729 {
1730 	long l = *lp;
1731 
1732 	if ((l >= 0) ? (m > LONG_MAX - l) : (m < LONG_MIN - l))
1733 		return TRUE;
1734 	*lp += m;
1735 	return FALSE;
1736 }
1737 
1738 static int
1739 normalize_overflow(int *const tensptr, int *const unitsptr, const int base)
1740 {
1741 	int	tensdelta;
1742 
1743 	tensdelta = (*unitsptr >= 0) ?
1744 		(*unitsptr / base) :
1745 		(-1 - (-1 - *unitsptr) / base);
1746 	*unitsptr -= tensdelta * base;
1747 	return increment_overflow(tensptr, tensdelta);
1748 }
1749 
1750 static int
1751 long_normalize_overflow(long *const tensptr, int *const unitsptr,
1752     const int base)
1753 {
1754 	int	tensdelta;
1755 
1756 	tensdelta = (*unitsptr >= 0) ?
1757 		(*unitsptr / base) :
1758 		(-1 - (-1 - *unitsptr) / base);
1759 	*unitsptr -= tensdelta * base;
1760 	return long_increment_overflow(tensptr, tensdelta);
1761 }
1762 
1763 static int
1764 tmcomp(const struct tm *const atmp, const struct tm *const btmp)
1765 {
1766 	int	result;
1767 
1768 	if ((result = (atmp->tm_year - btmp->tm_year)) == 0 &&
1769 		(result = (atmp->tm_mon - btmp->tm_mon)) == 0 &&
1770 		(result = (atmp->tm_mday - btmp->tm_mday)) == 0 &&
1771 		(result = (atmp->tm_hour - btmp->tm_hour)) == 0 &&
1772 		(result = (atmp->tm_min - btmp->tm_min)) == 0)
1773 			result = atmp->tm_sec - btmp->tm_sec;
1774 	return result;
1775 }
1776 
1777 static time_t
1778 time2sub(const timezone_t sp, struct tm *const tmp, subfun_t funcp,
1779     const long offset, int *const okayp, const int do_norm_secs)
1780 {
1781 	int			dir;
1782 	int			i, j;
1783 	int			saved_seconds;
1784 	long			li;
1785 	time_t			lo;
1786 	time_t			hi;
1787 #ifdef NO_ERROR_IN_DST_GAP
1788 	time_t			ilo;
1789 #endif
1790 	long				y;
1791 	time_t				newt;
1792 	time_t				t;
1793 	struct tm			yourtm, mytm;
1794 
1795 	*okayp = FALSE;
1796 	yourtm = *tmp;
1797 #ifdef NO_ERROR_IN_DST_GAP
1798 again:
1799 #endif
1800 	if (do_norm_secs) {
1801 		if (normalize_overflow(&yourtm.tm_min, &yourtm.tm_sec,
1802 		    SECSPERMIN))
1803 			goto overflow;
1804 	}
1805 	if (normalize_overflow(&yourtm.tm_hour, &yourtm.tm_min, MINSPERHOUR))
1806 		goto overflow;
1807 	if (normalize_overflow(&yourtm.tm_mday, &yourtm.tm_hour, HOURSPERDAY))
1808 		goto overflow;
1809 	y = yourtm.tm_year;
1810 	if (long_normalize_overflow(&y, &yourtm.tm_mon, MONSPERYEAR))
1811 		goto overflow;
1812 	/*
1813 	** Turn y into an actual year number for now.
1814 	** It is converted back to an offset from TM_YEAR_BASE later.
1815 	*/
1816 	if (long_increment_overflow(&y, TM_YEAR_BASE))
1817 		goto overflow;
1818 	while (yourtm.tm_mday <= 0) {
1819 		if (long_increment_overflow(&y, -1))
1820 			goto overflow;
1821 		li = y + (1 < yourtm.tm_mon);
1822 		yourtm.tm_mday += year_lengths[isleap(li)];
1823 	}
1824 	while (yourtm.tm_mday > DAYSPERLYEAR) {
1825 		li = y + (1 < yourtm.tm_mon);
1826 		yourtm.tm_mday -= year_lengths[isleap(li)];
1827 		if (long_increment_overflow(&y, 1))
1828 			goto overflow;
1829 	}
1830 	for ( ; ; ) {
1831 		i = mon_lengths[isleap(y)][yourtm.tm_mon];
1832 		if (yourtm.tm_mday <= i)
1833 			break;
1834 		yourtm.tm_mday -= i;
1835 		if (++yourtm.tm_mon >= MONSPERYEAR) {
1836 			yourtm.tm_mon = 0;
1837 			if (long_increment_overflow(&y, 1))
1838 				goto overflow;
1839 		}
1840 	}
1841 	if (long_increment_overflow(&y, -TM_YEAR_BASE))
1842 		goto overflow;
1843 	yourtm.tm_year = (int)y;
1844 	if (yourtm.tm_year != y)
1845 		goto overflow;
1846 	if (yourtm.tm_sec >= 0 && yourtm.tm_sec < SECSPERMIN)
1847 		saved_seconds = 0;
1848 	else if (y + TM_YEAR_BASE < EPOCH_YEAR) {
1849 		/*
1850 		** We can't set tm_sec to 0, because that might push the
1851 		** time below the minimum representable time.
1852 		** Set tm_sec to 59 instead.
1853 		** This assumes that the minimum representable time is
1854 		** not in the same minute that a leap second was deleted from,
1855 		** which is a safer assumption than using 58 would be.
1856 		*/
1857 		if (increment_overflow(&yourtm.tm_sec, 1 - SECSPERMIN))
1858 			goto overflow;
1859 		saved_seconds = yourtm.tm_sec;
1860 		yourtm.tm_sec = SECSPERMIN - 1;
1861 	} else {
1862 		saved_seconds = yourtm.tm_sec;
1863 		yourtm.tm_sec = 0;
1864 	}
1865 	/*
1866 	** Do a binary search (this works whatever time_t's type is).
1867 	*/
1868 	/* LINTED const not */
1869 	if (!TYPE_SIGNED(time_t)) {
1870 		lo = 0;
1871 		hi = lo - 1;
1872 	/* LINTED const not */
1873 	} else if (!TYPE_INTEGRAL(time_t)) {
1874 		/* CONSTCOND */
1875 		if (sizeof(time_t) > sizeof(float))
1876 			/* LINTED assumed double */
1877 			hi = (time_t) DBL_MAX;
1878 			/* LINTED assumed float */
1879 		else	hi = (time_t) FLT_MAX;
1880 		lo = -hi;
1881 	} else {
1882 		lo = 1;
1883 		for (i = 0; i < (int) TYPE_BIT(time_t) - 1; ++i)
1884 			lo *= 2;
1885 		hi = -(lo + 1);
1886 	}
1887 #ifdef NO_ERROR_IN_DST_GAP
1888 	ilo = lo;
1889 #endif
1890 	for ( ; ; ) {
1891 		t = lo / 2 + hi / 2;
1892 		if (t < lo)
1893 			t = lo;
1894 		else if (t > hi)
1895 			t = hi;
1896 		if ((*funcp)(sp, &t, offset, &mytm) == NULL) {
1897 			/*
1898 			** Assume that t is too extreme to be represented in
1899 			** a struct tm; arrange things so that it is less
1900 			** extreme on the next pass.
1901 			*/
1902 			dir = (t > 0) ? 1 : -1;
1903 		} else	dir = tmcomp(&mytm, &yourtm);
1904 		if (dir != 0) {
1905 			if (t == lo) {
1906 				++t;
1907 				if (t <= lo)
1908 					goto overflow;
1909 				++lo;
1910 			} else if (t == hi) {
1911 				--t;
1912 				if (t >= hi)
1913 					goto overflow;
1914 				--hi;
1915 			}
1916 #ifdef NO_ERROR_IN_DST_GAP
1917 			if (ilo != lo && lo - 1 == hi && yourtm.tm_isdst < 0 &&
1918 			    do_norm_secs) {
1919 				for (i = sp->typecnt - 1; i >= 0; --i) {
1920 					for (j = sp->typecnt - 1; j >= 0; --j) {
1921 						time_t off;
1922 						if (sp->ttis[j].tt_isdst ==
1923 						    sp->ttis[i].tt_isdst)
1924 							continue;
1925 						off = sp->ttis[j].tt_gmtoff -
1926 						    sp->ttis[i].tt_gmtoff;
1927 						yourtm.tm_sec += off < 0 ?
1928 						    -off : off;
1929 						goto again;
1930 					}
1931 				}
1932 			}
1933 #endif
1934 			if (lo > hi)
1935 				goto invalid;
1936 			if (dir > 0)
1937 				hi = t;
1938 			else	lo = t;
1939 			continue;
1940 		}
1941 		if (yourtm.tm_isdst < 0 || mytm.tm_isdst == yourtm.tm_isdst)
1942 			break;
1943 		/*
1944 		** Right time, wrong type.
1945 		** Hunt for right time, right type.
1946 		** It's okay to guess wrong since the guess
1947 		** gets checked.
1948 		*/
1949 		if (sp == NULL)
1950 			goto invalid;
1951 		for (i = sp->typecnt - 1; i >= 0; --i) {
1952 			if (sp->ttis[i].tt_isdst != yourtm.tm_isdst)
1953 				continue;
1954 			for (j = sp->typecnt - 1; j >= 0; --j) {
1955 				if (sp->ttis[j].tt_isdst == yourtm.tm_isdst)
1956 					continue;
1957 				newt = (time_t)(t + sp->ttis[j].tt_gmtoff -
1958 				    sp->ttis[i].tt_gmtoff);
1959 				if ((*funcp)(sp, &newt, offset, &mytm) == NULL)
1960 					continue;
1961 				if (tmcomp(&mytm, &yourtm) != 0)
1962 					continue;
1963 				if (mytm.tm_isdst != yourtm.tm_isdst)
1964 					continue;
1965 				/*
1966 				** We have a match.
1967 				*/
1968 				t = newt;
1969 				goto label;
1970 			}
1971 		}
1972 		goto invalid;
1973 	}
1974 label:
1975 	newt = t + saved_seconds;
1976 	if ((newt < t) != (saved_seconds < 0))
1977 		goto overflow;
1978 	t = newt;
1979 	if ((*funcp)(sp, &t, offset, tmp)) {
1980 		*okayp = TRUE;
1981 		return t;
1982 	}
1983 overflow:
1984 	errno = EOVERFLOW;
1985 	return WRONG;
1986 invalid:
1987 	errno = EINVAL;
1988 	return WRONG;
1989 }
1990 
1991 static time_t
1992 time2(const timezone_t sp, struct tm *const tmp, subfun_t funcp,
1993     const long offset, int *const okayp)
1994 {
1995 	time_t	t;
1996 
1997 	/*
1998 	** First try without normalization of seconds
1999 	** (in case tm_sec contains a value associated with a leap second).
2000 	** If that fails, try with normalization of seconds.
2001 	*/
2002 	t = time2sub(sp, tmp, funcp, offset, okayp, FALSE);
2003 	return *okayp ? t : time2sub(sp, tmp, funcp, offset, okayp, TRUE);
2004 }
2005 
2006 static time_t
2007 time1(const timezone_t sp, struct tm *const tmp, subfun_t funcp,
2008     const long offset)
2009 {
2010 	time_t			t;
2011 	int			samei, otheri;
2012 	int			sameind, otherind;
2013 	int			i;
2014 	int			nseen;
2015 	int				seen[TZ_MAX_TYPES];
2016 	int				types[TZ_MAX_TYPES];
2017 	int				okay;
2018 
2019 	if (tmp == NULL) {
2020 		errno = EINVAL;
2021 		return WRONG;
2022 	}
2023 	if (tmp->tm_isdst > 1)
2024 		tmp->tm_isdst = 1;
2025 	t = time2(sp, tmp, funcp, offset, &okay);
2026 #ifdef PCTS
2027 	/*
2028 	** PCTS code courtesy Grant Sullivan.
2029 	*/
2030 	if (okay)
2031 		return t;
2032 	if (tmp->tm_isdst < 0)
2033 		tmp->tm_isdst = 0;	/* reset to std and try again */
2034 #endif /* defined PCTS */
2035 #ifndef PCTS
2036 	if (okay || tmp->tm_isdst < 0)
2037 		return t;
2038 #endif /* !defined PCTS */
2039 	/*
2040 	** We're supposed to assume that somebody took a time of one type
2041 	** and did some math on it that yielded a "struct tm" that's bad.
2042 	** We try to divine the type they started from and adjust to the
2043 	** type they need.
2044 	*/
2045 	if (sp == NULL) {
2046 		errno = EINVAL;
2047 		return WRONG;
2048 	}
2049 	for (i = 0; i < sp->typecnt; ++i)
2050 		seen[i] = FALSE;
2051 	nseen = 0;
2052 	for (i = sp->timecnt - 1; i >= 0; --i)
2053 		if (!seen[sp->types[i]]) {
2054 			seen[sp->types[i]] = TRUE;
2055 			types[nseen++] = sp->types[i];
2056 		}
2057 	for (sameind = 0; sameind < nseen; ++sameind) {
2058 		samei = types[sameind];
2059 		if (sp->ttis[samei].tt_isdst != tmp->tm_isdst)
2060 			continue;
2061 		for (otherind = 0; otherind < nseen; ++otherind) {
2062 			otheri = types[otherind];
2063 			if (sp->ttis[otheri].tt_isdst == tmp->tm_isdst)
2064 				continue;
2065 			tmp->tm_sec += (int)(sp->ttis[otheri].tt_gmtoff -
2066 					sp->ttis[samei].tt_gmtoff);
2067 			tmp->tm_isdst = !tmp->tm_isdst;
2068 			t = time2(sp, tmp, funcp, offset, &okay);
2069 			if (okay)
2070 				return t;
2071 			tmp->tm_sec -= (int)(sp->ttis[otheri].tt_gmtoff -
2072 					sp->ttis[samei].tt_gmtoff);
2073 			tmp->tm_isdst = !tmp->tm_isdst;
2074 		}
2075 	}
2076 	errno = EOVERFLOW;
2077 	return WRONG;
2078 }
2079 
2080 time_t
2081 mktime_z(const timezone_t sp, struct tm *const tmp)
2082 {
2083 	time_t t;
2084 	if (sp == NULL)
2085 		t = time1(NULL, tmp, gmtsub, 0L);
2086 	else
2087 		t = time1(sp, tmp, localsub, 0L);
2088 	return t;
2089 }
2090 
2091 time_t
2092 mktime(struct tm *const tmp)
2093 {
2094 	time_t result;
2095 
2096 	rwlock_wrlock(&lcl_lock);
2097 	tzset_unlocked();
2098 	result = mktime_z(lclptr, tmp);
2099 	rwlock_unlock(&lcl_lock);
2100 	return result;
2101 }
2102 
2103 #ifdef STD_INSPIRED
2104 
2105 time_t
2106 timelocal_z(const timezone_t sp, struct tm *const tmp)
2107 {
2108 	if (tmp != NULL)
2109 		tmp->tm_isdst = -1;	/* in case it wasn't initialized */
2110 	return mktime_z(sp, tmp);
2111 }
2112 
2113 time_t
2114 timelocal(struct tm *const tmp)
2115 {
2116 	if (tmp != NULL)
2117 		tmp->tm_isdst = -1;	/* in case it wasn't initialized */
2118 	return mktime(tmp);
2119 }
2120 
2121 time_t
2122 timegm(struct tm *const tmp)
2123 {
2124 	time_t t;
2125 
2126 	if (tmp != NULL)
2127 		tmp->tm_isdst = 0;
2128 	t = time1(gmtptr, tmp, gmtsub, 0L);
2129 	return t;
2130 }
2131 
2132 time_t
2133 timeoff(struct tm *const tmp, const long offset)
2134 {
2135 	time_t t;
2136 
2137 	if (tmp != NULL)
2138 		tmp->tm_isdst = 0;
2139 	t = time1(gmtptr, tmp, gmtsub, offset);
2140 	return t;
2141 }
2142 
2143 #endif /* defined STD_INSPIRED */
2144 
2145 #ifdef CMUCS
2146 
2147 /*
2148 ** The following is supplied for compatibility with
2149 ** previous versions of the CMUCS runtime library.
2150 */
2151 
2152 long
2153 gtime(struct tm *const tmp)
2154 {
2155 	const time_t t = mktime(tmp);
2156 
2157 	if (t == WRONG)
2158 		return -1;
2159 	return t;
2160 }
2161 
2162 #endif /* defined CMUCS */
2163 
2164 /*
2165 ** XXX--is the below the right way to conditionalize??
2166 */
2167 
2168 #ifdef STD_INSPIRED
2169 
2170 /*
2171 ** IEEE Std 1003.1-1988 (POSIX) legislates that 536457599
2172 ** shall correspond to "Wed Dec 31 23:59:59 UTC 1986", which
2173 ** is not the case if we are accounting for leap seconds.
2174 ** So, we provide the following conversion routines for use
2175 ** when exchanging timestamps with POSIX conforming systems.
2176 */
2177 
2178 static long
2179 leapcorr(const timezone_t sp, time_t *timep)
2180 {
2181 	struct lsinfo * lp;
2182 	int		i;
2183 
2184 	i = sp->leapcnt;
2185 	while (--i >= 0) {
2186 		lp = &sp->lsis[i];
2187 		if (*timep >= lp->ls_trans)
2188 			return lp->ls_corr;
2189 	}
2190 	return 0;
2191 }
2192 
2193 time_t
2194 time2posix_z(const timezone_t sp, time_t t)
2195 {
2196 	return (time_t)(t - leapcorr(sp, &t));
2197 }
2198 
2199 time_t
2200 time2posix(time_t t)
2201 {
2202 	time_t result;
2203 	rwlock_wrlock(&lcl_lock);
2204 	tzset_unlocked();
2205 	result = (time_t)(t - leapcorr(lclptr, &t));
2206 	rwlock_unlock(&lcl_lock);
2207 	return (result);
2208 }
2209 
2210 time_t
2211 posix2time_z(const timezone_t sp, time_t t)
2212 {
2213 	time_t	x;
2214 	time_t	y;
2215 
2216 	/*
2217 	** For a positive leap second hit, the result
2218 	** is not unique. For a negative leap second
2219 	** hit, the corresponding time doesn't exist,
2220 	** so we return an adjacent second.
2221 	*/
2222 	x = (time_t)(t + leapcorr(sp, &t));
2223 	y = (time_t)(x - leapcorr(sp, &x));
2224 	if (y < t) {
2225 		do {
2226 			x++;
2227 			y = (time_t)(x - leapcorr(sp, &x));
2228 		} while (y < t);
2229 		if (t != y) {
2230 			return x - 1;
2231 		}
2232 	} else if (y > t) {
2233 		do {
2234 			--x;
2235 			y = (time_t)(x - leapcorr(sp, &x));
2236 		} while (y > t);
2237 		if (t != y) {
2238 			return x + 1;
2239 		}
2240 	}
2241 	return x;
2242 }
2243 
2244 
2245 
2246 time_t
2247 posix2time(time_t t)
2248 {
2249 	time_t result;
2250 
2251 	rwlock_wrlock(&lcl_lock);
2252 	tzset_unlocked();
2253 	result = posix2time_z(lclptr, t);
2254 	rwlock_unlock(&lcl_lock);
2255 	return result;
2256 }
2257 
2258 #endif /* defined STD_INSPIRED */
2259