xref: /netbsd-src/lib/libc/time/localtime.c (revision 80d9064ac03cbb6a4174695f0d5b237c8766d3d0)
1 /*	$NetBSD: localtime.c,v 1.86 2014/09/18 13:58:20 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 1.86 2014/09/18 13:58:20 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 <assert.h>
26 #include "private.h"
27 #include "tzfile.h"
28 #include "fcntl.h"
29 #include "reentrant.h"
30 
31 #if defined(__weak_alias)
32 __weak_alias(daylight,_daylight)
33 __weak_alias(tzname,_tzname)
34 #endif
35 
36 #ifndef TZ_ABBR_MAX_LEN
37 #define TZ_ABBR_MAX_LEN	16
38 #endif /* !defined TZ_ABBR_MAX_LEN */
39 
40 #ifndef TZ_ABBR_CHAR_SET
41 #define TZ_ABBR_CHAR_SET \
42 	"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789 :+-._"
43 #endif /* !defined TZ_ABBR_CHAR_SET */
44 
45 #ifndef TZ_ABBR_ERR_CHAR
46 #define TZ_ABBR_ERR_CHAR	'_'
47 #endif /* !defined TZ_ABBR_ERR_CHAR */
48 
49 /* The minimum and maximum finite time values.  */
50 static time_t const time_t_min =
51   (TYPE_SIGNED(time_t)
52    ? (time_t) -1 << (int)(CHAR_BIT * sizeof (time_t) - 1)
53    : 0);
54 static time_t const time_t_max =
55   (TYPE_SIGNED(time_t)
56    ? - (~ 0 < 0) - ((time_t) -1 << (int)(CHAR_BIT * sizeof (time_t) - 1))
57    : -1);
58 
59 /*
60 ** SunOS 4.1.1 headers lack O_BINARY.
61 */
62 
63 #ifdef O_BINARY
64 #define OPEN_MODE	(O_RDONLY | O_BINARY | O_CLOEXEC)
65 #endif /* defined O_BINARY */
66 #ifndef O_BINARY
67 #define OPEN_MODE	(O_RDONLY | O_CLOEXEC)
68 #endif /* !defined O_BINARY */
69 
70 #ifndef WILDABBR
71 /*
72 ** Someone might make incorrect use of a time zone abbreviation:
73 **	1.	They might reference tzname[0] before calling tzset (explicitly
74 **		or implicitly).
75 **	2.	They might reference tzname[1] before calling tzset (explicitly
76 **		or implicitly).
77 **	3.	They might reference tzname[1] after setting to a time zone
78 **		in which Daylight Saving Time is never observed.
79 **	4.	They might reference tzname[0] after setting to a time zone
80 **		in which Standard Time is never observed.
81 **	5.	They might reference tm.TM_ZONE after calling offtime.
82 ** What's best to do in the above cases is open to debate;
83 ** for now, we just set things up so that in any of the five cases
84 ** WILDABBR is used. Another possibility: initialize tzname[0] to the
85 ** string "tzname[0] used before set", and similarly for the other cases.
86 ** And another: initialize tzname[0] to "ERA", with an explanation in the
87 ** manual page of what this "time zone abbreviation" means (doing this so
88 ** that tzname[0] has the "normal" length of three characters).
89 */
90 #define WILDABBR	"   "
91 #endif /* !defined WILDABBR */
92 
93 static const char	wildabbr[] = WILDABBR;
94 
95 static const char	gmt[] = "GMT";
96 
97 /*
98 ** The DST rules to use if TZ has no rules and we can't load TZDEFRULES.
99 ** We default to US rules as of 1999-08-17.
100 ** POSIX 1003.1 section 8.1.1 says that the default DST rules are
101 ** implementation dependent; for historical reasons, US rules are a
102 ** common default.
103 */
104 #ifndef TZDEFRULESTRING
105 #define TZDEFRULESTRING ",M4.1.0,M10.5.0"
106 #endif /* !defined TZDEFDST */
107 
108 struct ttinfo {				/* time type information */
109 	int_fast32_t	tt_gmtoff;	/* UT offset in seconds */
110 	int		tt_isdst;	/* used to set tm_isdst */
111 	int		tt_abbrind;	/* abbreviation list index */
112 	int		tt_ttisstd;	/* TRUE if transition is std time */
113 	int		tt_ttisgmt;	/* TRUE if transition is UT */
114 };
115 
116 struct lsinfo {				/* leap second information */
117 	time_t		ls_trans;	/* transition time */
118 	int_fast64_t	ls_corr;	/* correction to apply */
119 };
120 
121 #define BIGGEST(a, b)	(((a) > (b)) ? (a) : (b))
122 
123 #ifdef TZNAME_MAX
124 #define MY_TZNAME_MAX	TZNAME_MAX
125 #endif /* defined TZNAME_MAX */
126 #ifndef TZNAME_MAX
127 #define MY_TZNAME_MAX	255
128 #endif /* !defined TZNAME_MAX */
129 
130 struct __state {
131 	int		leapcnt;
132 	int		timecnt;
133 	int		typecnt;
134 	int		charcnt;
135 	int		goback;
136 	int		goahead;
137 	time_t		ats[TZ_MAX_TIMES];
138 	unsigned char	types[TZ_MAX_TIMES];
139 	struct ttinfo	ttis[TZ_MAX_TYPES];
140 	char		chars[/*CONSTCOND*/BIGGEST(BIGGEST(TZ_MAX_CHARS + 1,
141 				sizeof gmt), (2 * (MY_TZNAME_MAX + 1)))];
142 	struct lsinfo	lsis[TZ_MAX_LEAPS];
143 	int		defaulttype; /* for early times or if no transitions */
144 };
145 
146 struct rule {
147 	int		r_type;		/* type of rule; see below */
148 	int		r_day;		/* day number of rule */
149 	int		r_week;		/* week number of rule */
150 	int		r_mon;		/* month number of rule */
151 	int_fast32_t	r_time;		/* transition time of rule */
152 };
153 
154 #define JULIAN_DAY		0	/* Jn = Julian day */
155 #define DAY_OF_YEAR		1	/* n = day of year */
156 #define MONTH_NTH_DAY_OF_WEEK	2	/* Mm.n.d = month, week, day of week */
157 
158 typedef struct tm *(*subfun_t)(const timezone_t sp, const time_t *timep,
159 			       const int_fast32_t offset, struct tm *tmp);
160 
161 /*
162 ** Prototypes for static functions.
163 */
164 
165 static int_fast32_t	detzcode(const char * codep);
166 static int_fast64_t	detzcode64(const char * codep);
167 static int		differ_by_repeat(time_t t1, time_t t0);
168 static const char *	getzname(const char * strp) ATTRIBUTE_PURE;
169 static const char *	getqzname(const char * strp, const int delim) ATTRIBUTE_PURE;
170 static const char *	getnum(const char * strp, int * nump, int min,
171 				int max);
172 static const char *	getsecs(const char * strp, int_fast32_t * secsp);
173 static const char *	getoffset(const char * strp, int_fast32_t * offsetp);
174 static const char *	getrule(const char * strp, struct rule * rulep);
175 static void		gmtload(timezone_t sp);
176 static struct tm *	gmtsub(const timezone_t sp, const time_t *timep,
177 				const int_fast32_t offset, struct tm * tmp);
178 static struct tm *	localsub(const timezone_t sp, const time_t *timep,
179 				const int_fast32_t offset, struct tm *tmp);
180 static int		increment_overflow(int * number, int delta);
181 static int		increment_overflow32(int_fast32_t * number, int delta);
182 static int		increment_overflow_time(time_t *t, int_fast32_t delta);
183 static int		leaps_thru_end_of(int y) ATTRIBUTE_PURE;
184 static int		normalize_overflow(int * tensptr, int * unitsptr,
185 				int base);
186 static int		normalize_overflow32(int_fast32_t * tensptr,
187 				int * unitsptr, int base);
188 static void		settzname(void);
189 static time_t		time1(const timezone_t sp, struct tm * const tmp,
190 				subfun_t funcp, const int_fast32_t offset);
191 static time_t		time2(const timezone_t sp, struct tm * const tmp,
192 				subfun_t funcp,
193 				const int_fast32_t offset, int *const okayp);
194 static time_t		time2sub(const timezone_t sp, struct tm * const tmp,
195 				subfun_t funcp, const int_fast32_t offset,
196 				int *const okayp, const int do_norm_secs);
197 static struct tm *	timesub(const timezone_t sp, const time_t * timep,
198 				const int_fast32_t offset, struct tm * tmp);
199 static int		tmcomp(const struct tm * atmp,
200 				const struct tm * btmp);
201 static int_fast32_t	transtime(int year, const struct rule * rulep,
202 				  int_fast32_t offset)
203   ATTRIBUTE_PURE;
204 static int		typesequiv(const timezone_t sp, int a, int b);
205 static int		tzload(timezone_t sp, const char * name,
206 				int doextend);
207 static int		tzparse(timezone_t sp, const char * name,
208 				int lastditch);
209 static void		tzset_unlocked(void);
210 static void		tzsetwall_unlocked(void);
211 static int_fast64_t	leapcorr(const timezone_t sp, time_t * timep);
212 
213 static timezone_t lclptr;
214 static timezone_t gmtptr;
215 
216 #ifndef TZ_STRLEN_MAX
217 #define TZ_STRLEN_MAX 255
218 #endif /* !defined TZ_STRLEN_MAX */
219 
220 static char		lcl_TZname[TZ_STRLEN_MAX + 1];
221 static int		lcl_is_set;
222 static int		gmt_is_set;
223 
224 #if !defined(__LIBC12_SOURCE__)
225 
226 __aconst char *		tzname[2] = {
227 	(__aconst char *)__UNCONST(wildabbr),
228 	(__aconst char *)__UNCONST(wildabbr)
229 };
230 
231 #else
232 
233 extern __aconst char *	tzname[2];
234 
235 #endif
236 
237 #ifdef _REENTRANT
238 static rwlock_t lcl_lock = RWLOCK_INITIALIZER;
239 #endif
240 
241 /*
242 ** Section 4.12.3 of X3.159-1989 requires that
243 **	Except for the strftime function, these functions [asctime,
244 **	ctime, gmtime, localtime] return values in one of two static
245 **	objects: a broken-down time structure and an array of char.
246 ** Thanks to Paul Eggert for noting this.
247 */
248 
249 static struct tm	tm;
250 
251 #ifdef USG_COMPAT
252 #if !defined(__LIBC12_SOURCE__)
253 long 			timezone = 0;
254 int			daylight = 0;
255 #else
256 extern int		daylight;
257 extern long		timezone __RENAME(__timezone13);
258 #endif
259 #endif /* defined USG_COMPAT */
260 
261 #ifdef ALTZONE
262 long			altzone = 0;
263 #endif /* defined ALTZONE */
264 
265 static int_fast32_t
266 detzcode(const char *const codep)
267 {
268 	int_fast32_t	result;
269 	int	i;
270 
271 	result = (codep[0] & 0x80) ? -1 : 0;
272 	for (i = 0; i < 4; ++i)
273 		result = (result << 8) | (codep[i] & 0xff);
274 	return result;
275 }
276 
277 static int_fast64_t
278 detzcode64(const char *const codep)
279 {
280 	int_fast64_t	result;
281 	int	i;
282 
283 	result = (codep[0] & 0x80) ? -1 : 0;
284 	for (i = 0; i < 8; ++i)
285 		result = (result << 8) | (codep[i] & 0xff);
286 	return result;
287 }
288 
289 const char *
290 tzgetname(const timezone_t sp, int isdst)
291 {
292 	int i;
293 	for (i = 0; i < sp->timecnt; ++i) {
294 		const struct ttinfo *const ttisp = &sp->ttis[sp->types[i]];
295 
296 		if (ttisp->tt_isdst == isdst)
297 			return &sp->chars[ttisp->tt_abbrind];
298 	}
299 	return NULL;
300 }
301 
302 static void
303 settzname_z(timezone_t sp)
304 {
305 	int			i;
306 
307 	/*
308 	** Scrub the abbreviations.
309 	** First, replace bogus characters.
310 	*/
311 	for (i = 0; i < sp->charcnt; ++i)
312 		if (strchr(TZ_ABBR_CHAR_SET, sp->chars[i]) == NULL)
313 			sp->chars[i] = TZ_ABBR_ERR_CHAR;
314 	/*
315 	** Second, truncate long abbreviations.
316 	*/
317 	for (i = 0; i < sp->typecnt; ++i) {
318 		const struct ttinfo * const	ttisp = &sp->ttis[i];
319 		char *				cp = &sp->chars[ttisp->tt_abbrind];
320 
321 		if (strlen(cp) > TZ_ABBR_MAX_LEN &&
322 			strcmp(cp, GRANDPARENTED) != 0)
323 				*(cp + TZ_ABBR_MAX_LEN) = '\0';
324 	}
325 }
326 
327 static void
328 settzname(void)
329 {
330 	timezone_t const	sp = lclptr;
331 	int			i;
332 
333 	tzname[0] = (__aconst char *)__UNCONST(wildabbr);
334 	tzname[1] = (__aconst char *)__UNCONST(wildabbr);
335 #ifdef USG_COMPAT
336 	daylight = 0;
337 	timezone = 0;
338 #endif /* defined USG_COMPAT */
339 #ifdef ALTZONE
340 	altzone = 0;
341 #endif /* defined ALTZONE */
342 	if (sp == NULL) {
343 		tzname[0] = tzname[1] = (__aconst char *)__UNCONST(gmt);
344 		return;
345 	}
346 	/*
347 	** And to get the latest zone names into tzname. . .
348 	*/
349 	for (i = 0; i < sp->typecnt; ++i) {
350 		const struct ttinfo * const	ttisp = &sp->ttis[i];
351 
352 		tzname[ttisp->tt_isdst] = &sp->chars[ttisp->tt_abbrind];
353 #ifdef USG_COMPAT
354 		if (ttisp->tt_isdst)
355 			daylight = 1;
356 		if (!ttisp->tt_isdst)
357 			timezone = -(ttisp->tt_gmtoff);
358 #endif /* defined USG_COMPAT */
359 #ifdef ALTZONE
360 		if (ttisp->tt_isdst)
361 			altzone = -(ttisp->tt_gmtoff);
362 #endif /* defined ALTZONE */
363 	}
364 	settzname_z(sp);
365 }
366 
367 static int
368 differ_by_repeat(const time_t t1, const time_t t0)
369 {
370 	if (TYPE_BIT(time_t) - TYPE_SIGNED(time_t) < SECSPERREPEAT_BITS)
371 		return 0;
372 	return (int_fast64_t)t1 - (int_fast64_t)t0 == SECSPERREPEAT;
373 }
374 
375 static int
376 tzload(timezone_t sp, const char *name, const int doextend)
377 {
378 	const char *		p;
379 	int			i;
380 	int			fid;
381 	int			stored;
382 	ssize_t			nread;
383 	typedef union {
384 		struct tzhead	tzhead;
385 		char		buf[2 * sizeof(struct tzhead) +
386 					2 * sizeof *sp +
387 					4 * TZ_MAX_TIMES];
388 	} u_t;
389 	union local_storage {
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 		/* The main part of the storage for this function.  */
400 		struct {
401 			u_t u;
402 			struct __state st;
403 		} u;
404 	};
405 	char *fullname;
406 	u_t *up;
407 	int doaccess;
408 	union local_storage *lsp;
409 	lsp = malloc(sizeof *lsp);
410 	if (!lsp)
411 		return -1;
412 	fullname = lsp->fullname;
413 	up = &lsp->u.u;
414 
415 	sp->goback = sp->goahead = FALSE;
416 
417 	if (! name) {
418 		name = TZDEFAULT;
419 		if (! name)
420 			goto oops;
421 	}
422 
423 	if (name[0] == ':')
424 		++name;
425 	doaccess = name[0] == '/';
426 	if (!doaccess) {
427 		p = TZDIR;
428 		if (! p || sizeof lsp->fullname - 1 <= strlen(p) + strlen(name))
429 			goto oops;
430 		strcpy(fullname, p);
431 		strcat(fullname, "/");
432 		strcat(fullname, name);
433 		/* Set doaccess if '.' (as in "../") shows up in name.  */
434 		if (strchr(name, '.'))
435 			doaccess = TRUE;
436 		name = fullname;
437 	}
438 	if (doaccess && access(name, R_OK) != 0)
439 		goto oops;
440 
441 	fid = open(name, OPEN_MODE);
442 	if (fid < 0)
443 		goto oops;
444 	nread = read(fid, up->buf, sizeof up->buf);
445 	if (close(fid) < 0 || nread <= 0)
446 		goto oops;
447 	for (stored = 4; stored <= 8; stored *= 2) {
448 		int		ttisstdcnt;
449 		int		ttisgmtcnt;
450 		int		timecnt;
451 
452 		ttisstdcnt = (int) detzcode(up->tzhead.tzh_ttisstdcnt);
453 		ttisgmtcnt = (int) detzcode(up->tzhead.tzh_ttisgmtcnt);
454 		sp->leapcnt = (int) detzcode(up->tzhead.tzh_leapcnt);
455 		sp->timecnt = (int) detzcode(up->tzhead.tzh_timecnt);
456 		sp->typecnt = (int) detzcode(up->tzhead.tzh_typecnt);
457 		sp->charcnt = (int) detzcode(up->tzhead.tzh_charcnt);
458 		p = up->tzhead.tzh_charcnt + sizeof up->tzhead.tzh_charcnt;
459 		if (sp->leapcnt < 0 || sp->leapcnt > TZ_MAX_LEAPS ||
460 			sp->typecnt <= 0 || sp->typecnt > TZ_MAX_TYPES ||
461 			sp->timecnt < 0 || sp->timecnt > TZ_MAX_TIMES ||
462 			sp->charcnt < 0 || sp->charcnt > TZ_MAX_CHARS ||
463 			(ttisstdcnt != sp->typecnt && ttisstdcnt != 0) ||
464 			(ttisgmtcnt != sp->typecnt && ttisgmtcnt != 0))
465 				goto oops;
466 		if (nread - (p - up->buf) <
467 			sp->timecnt * stored +		/* ats */
468 			sp->timecnt +			/* types */
469 			sp->typecnt * 6 +		/* ttinfos */
470 			sp->charcnt +			/* chars */
471 			sp->leapcnt * (stored + 4) +	/* lsinfos */
472 			ttisstdcnt +			/* ttisstds */
473 			ttisgmtcnt)			/* ttisgmts */
474 				goto oops;
475 		timecnt = 0;
476 		for (i = 0; i < sp->timecnt; ++i) {
477 			int_fast64_t at
478 			  = stored == 4 ? detzcode(p) : detzcode64(p);
479 			sp->types[i] = ((TYPE_SIGNED(time_t)
480 					 ? time_t_min <= at
481 					 : 0 <= at)
482 					&& at <= time_t_max);
483 			if (sp->types[i]) {
484 				if (i && !timecnt && at != time_t_min) {
485 					/*
486 					** Keep the earlier record, but tweak
487 					** it so that it starts with the
488 					** minimum time_t value.
489 					*/
490 					sp->types[i - 1] = 1;
491 					sp->ats[timecnt++] = time_t_min;
492 				}
493 				_DIAGASSERT(__type_fit(time_t, at));
494 				sp->ats[timecnt++] = (time_t)at;
495 			}
496 			p += stored;
497 		}
498 		timecnt = 0;
499 		for (i = 0; i < sp->timecnt; ++i) {
500 			unsigned char typ = *p++;
501 			if (sp->typecnt <= typ)
502 				goto oops;
503 			if (sp->types[i])
504 				sp->types[timecnt++] = typ;
505 		}
506 		for (i = 0; i < sp->typecnt; ++i) {
507 			struct ttinfo *	ttisp;
508 
509 			ttisp = &sp->ttis[i];
510 			ttisp->tt_gmtoff = detzcode(p);
511 			p += 4;
512 			ttisp->tt_isdst = (unsigned char) *p++;
513 			if (ttisp->tt_isdst != 0 && ttisp->tt_isdst != 1)
514 				goto oops;
515 			ttisp->tt_abbrind = (unsigned char) *p++;
516 			if (ttisp->tt_abbrind < 0 ||
517 				ttisp->tt_abbrind > sp->charcnt)
518 					goto oops;
519 		}
520 		for (i = 0; i < sp->charcnt; ++i)
521 			sp->chars[i] = *p++;
522 		sp->chars[i] = '\0';	/* ensure '\0' at end */
523 		for (i = 0; i < sp->leapcnt; ++i) {
524 			struct lsinfo *	lsisp;
525 
526 			lsisp = &sp->lsis[i];
527 			lsisp->ls_trans = (time_t)((stored == 4) ?
528 			    detzcode(p) : detzcode64(p));
529 			p += stored;
530 			lsisp->ls_corr = detzcode(p);
531 			p += 4;
532 		}
533 		for (i = 0; i < sp->typecnt; ++i) {
534 			struct ttinfo *	ttisp;
535 
536 			ttisp = &sp->ttis[i];
537 			if (ttisstdcnt == 0)
538 				ttisp->tt_ttisstd = FALSE;
539 			else {
540 				ttisp->tt_ttisstd = *p++;
541 				if (ttisp->tt_ttisstd != TRUE &&
542 					ttisp->tt_ttisstd != FALSE)
543 						goto oops;
544 			}
545 		}
546 		for (i = 0; i < sp->typecnt; ++i) {
547 			struct ttinfo *	ttisp;
548 
549 			ttisp = &sp->ttis[i];
550 			if (ttisgmtcnt == 0)
551 				ttisp->tt_ttisgmt = FALSE;
552 			else {
553 				ttisp->tt_ttisgmt = *p++;
554 				if (ttisp->tt_ttisgmt != TRUE &&
555 					ttisp->tt_ttisgmt != FALSE)
556 						goto oops;
557 			}
558 		}
559 		/*
560 		** If this is an old file, we're done.
561 		*/
562 		if (up->tzhead.tzh_version[0] == '\0')
563 			break;
564 		nread -= p - up->buf;
565 		for (i = 0; i < nread; ++i)
566 			up->buf[i] = p[i];
567 		/*
568 		** If this is a signed narrow time_t system, we're done.
569 		*/
570 		if (TYPE_SIGNED(time_t) && stored >= (int) sizeof(time_t))
571 			break;
572 	}
573 	if (doextend && nread > 2 &&
574 		up->buf[0] == '\n' && up->buf[nread - 1] == '\n' &&
575 		sp->typecnt + 2 <= TZ_MAX_TYPES) {
576 			struct __state *ts = &lsp->u.st;
577 			int	result;
578 
579 			up->buf[nread - 1] = '\0';
580 			result = tzparse(ts, &up->buf[1], FALSE);
581 			if (result == 0 && ts->typecnt == 2 &&
582 				sp->charcnt + ts->charcnt <= TZ_MAX_CHARS) {
583 					for (i = 0; i < 2; ++i)
584 						ts->ttis[i].tt_abbrind +=
585 							sp->charcnt;
586 					for (i = 0; i < ts->charcnt; ++i)
587 						sp->chars[sp->charcnt++] =
588 							ts->chars[i];
589 					i = 0;
590 					while (i < ts->timecnt &&
591 						ts->ats[i] <=
592 						sp->ats[sp->timecnt - 1])
593 							++i;
594 					while (i < ts->timecnt &&
595 					    sp->timecnt < TZ_MAX_TIMES) {
596 						sp->ats[sp->timecnt] =
597 							ts->ats[i];
598 						sp->types[sp->timecnt] =
599 							sp->typecnt +
600 							ts->types[i];
601 						++sp->timecnt;
602 						++i;
603 					}
604 					sp->ttis[sp->typecnt++] = ts->ttis[0];
605 					sp->ttis[sp->typecnt++] = ts->ttis[1];
606 			}
607 	}
608 	if (sp->timecnt > 1) {
609 		for (i = 1; i < sp->timecnt; ++i)
610 			if (typesequiv(sp, sp->types[i], sp->types[0]) &&
611 				differ_by_repeat(sp->ats[i], sp->ats[0])) {
612 					sp->goback = TRUE;
613 					break;
614 				}
615 		for (i = sp->timecnt - 2; i >= 0; --i)
616 			if (typesequiv(sp, sp->types[sp->timecnt - 1],
617 				sp->types[i]) &&
618 				differ_by_repeat(sp->ats[sp->timecnt - 1],
619 				sp->ats[i])) {
620 					sp->goahead = TRUE;
621 					break;
622 		}
623 	}
624 	/*
625 	** If type 0 is is unused in transitions,
626 	** it's the type to use for early times.
627 	*/
628 	for (i = 0; i < sp->typecnt; ++i)
629 		if (sp->types[i] == 0)
630 			break;
631 	i = (i >= sp->typecnt) ? 0 : -1;
632 	/*
633 	** Absent the above,
634 	** if there are transition times
635 	** and the first transition is to a daylight time
636 	** find the standard type less than and closest to
637 	** the type of the first transition.
638 	*/
639 	if (i < 0 && sp->timecnt > 0 && sp->ttis[sp->types[0]].tt_isdst) {
640 		i = sp->types[0];
641 		while (--i >= 0)
642 			if (!sp->ttis[i].tt_isdst)
643 				break;
644 	}
645 	/*
646 	** If no result yet, find the first standard type.
647 	** If there is none, punt to type zero.
648 	*/
649 	if (i < 0) {
650 		i = 0;
651 		while (sp->ttis[i].tt_isdst)
652 			if (++i >= sp->typecnt) {
653 				i = 0;
654 				break;
655 			}
656 	}
657 	sp->defaulttype = i;
658 	free(up);
659 	return 0;
660 oops:
661 	free(up);
662 	return -1;
663 }
664 
665 static int
666 typesequiv(const timezone_t sp, const int a, const int b)
667 {
668 	int	result;
669 
670 	if (sp == NULL ||
671 		a < 0 || a >= sp->typecnt ||
672 		b < 0 || b >= sp->typecnt)
673 			result = FALSE;
674 	else {
675 		const struct ttinfo *	ap = &sp->ttis[a];
676 		const struct ttinfo *	bp = &sp->ttis[b];
677 		result = ap->tt_gmtoff == bp->tt_gmtoff &&
678 			ap->tt_isdst == bp->tt_isdst &&
679 			ap->tt_ttisstd == bp->tt_ttisstd &&
680 			ap->tt_ttisgmt == bp->tt_ttisgmt &&
681 			strcmp(&sp->chars[ap->tt_abbrind],
682 			&sp->chars[bp->tt_abbrind]) == 0;
683 	}
684 	return result;
685 }
686 
687 static const int	mon_lengths[2][MONSPERYEAR] = {
688 	{ 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 },
689 	{ 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }
690 };
691 
692 static const int	year_lengths[2] = {
693 	DAYSPERNYEAR, DAYSPERLYEAR
694 };
695 
696 /*
697 ** Given a pointer into a time zone string, scan until a character that is not
698 ** a valid character in a zone name is found. Return a pointer to that
699 ** character.
700 */
701 
702 static const char *
703 getzname(const char *strp)
704 {
705 	char	c;
706 
707 	while ((c = *strp) != '\0' && !is_digit(c) && c != ',' && c != '-' &&
708 		c != '+')
709 			++strp;
710 	return strp;
711 }
712 
713 /*
714 ** Given a pointer into an extended time zone string, scan until the ending
715 ** delimiter of the zone name is located. Return a pointer to the delimiter.
716 **
717 ** As with getzname above, the legal character set is actually quite
718 ** restricted, with other characters producing undefined results.
719 ** We don't do any checking here; checking is done later in common-case code.
720 */
721 
722 static const char *
723 getqzname(const char *strp, const int delim)
724 {
725 	int	c;
726 
727 	while ((c = *strp) != '\0' && c != delim)
728 		++strp;
729 	return strp;
730 }
731 
732 /*
733 ** Given a pointer into a time zone string, extract a number from that string.
734 ** Check that the number is within a specified range; if it is not, return
735 ** NULL.
736 ** Otherwise, return a pointer to the first character not part of the number.
737 */
738 
739 static const char *
740 getnum(const char *strp, int *const nump, const int min, const int max)
741 {
742 	char	c;
743 	int	num;
744 
745 	if (strp == NULL || !is_digit(c = *strp)) {
746 		errno = EINVAL;
747 		return NULL;
748 	}
749 	num = 0;
750 	do {
751 		num = num * 10 + (c - '0');
752 		if (num > max) {
753 			errno = EOVERFLOW;
754 			return NULL;	/* illegal value */
755 		}
756 		c = *++strp;
757 	} while (is_digit(c));
758 	if (num < min) {
759 		errno = EINVAL;
760 		return NULL;		/* illegal value */
761 	}
762 	*nump = num;
763 	return strp;
764 }
765 
766 /*
767 ** Given a pointer into a time zone string, extract a number of seconds,
768 ** in hh[:mm[:ss]] form, from the string.
769 ** If any error occurs, return NULL.
770 ** Otherwise, return a pointer to the first character not part of the number
771 ** of seconds.
772 */
773 
774 static const char *
775 getsecs(const char *strp, int_fast32_t *const secsp)
776 {
777 	int	num;
778 
779 	/*
780 	** 'HOURSPERDAY * DAYSPERWEEK - 1' allows quasi-Posix rules like
781 	** "M10.4.6/26", which does not conform to Posix,
782 	** but which specifies the equivalent of
783 	** "02:00 on the first Sunday on or after 23 Oct".
784 	*/
785 	strp = getnum(strp, &num, 0, HOURSPERDAY * DAYSPERWEEK - 1);
786 	if (strp == NULL)
787 		return NULL;
788 	*secsp = num * (int_fast32_t) SECSPERHOUR;
789 	if (*strp == ':') {
790 		++strp;
791 		strp = getnum(strp, &num, 0, MINSPERHOUR - 1);
792 		if (strp == NULL)
793 			return NULL;
794 		*secsp += num * SECSPERMIN;
795 		if (*strp == ':') {
796 			++strp;
797 			/* 'SECSPERMIN' allows for leap seconds.  */
798 			strp = getnum(strp, &num, 0, SECSPERMIN);
799 			if (strp == NULL)
800 				return NULL;
801 			*secsp += num;
802 		}
803 	}
804 	return strp;
805 }
806 
807 /*
808 ** Given a pointer into a time zone string, extract an offset, in
809 ** [+-]hh[:mm[:ss]] form, from the string.
810 ** If any error occurs, return NULL.
811 ** Otherwise, return a pointer to the first character not part of the time.
812 */
813 
814 static const char *
815 getoffset(const char *strp, int_fast32_t *const offsetp)
816 {
817 	int	neg = 0;
818 
819 	if (*strp == '-') {
820 		neg = 1;
821 		++strp;
822 	} else if (*strp == '+')
823 		++strp;
824 	strp = getsecs(strp, offsetp);
825 	if (strp == NULL)
826 		return NULL;		/* illegal time */
827 	if (neg)
828 		*offsetp = -*offsetp;
829 	return strp;
830 }
831 
832 /*
833 ** Given a pointer into a time zone string, extract a rule in the form
834 ** date[/time]. See POSIX section 8 for the format of "date" and "time".
835 ** If a valid rule is not found, return NULL.
836 ** Otherwise, return a pointer to the first character not part of the rule.
837 */
838 
839 static const char *
840 getrule(const char *strp, struct rule *const rulep)
841 {
842 	if (*strp == 'J') {
843 		/*
844 		** Julian day.
845 		*/
846 		rulep->r_type = JULIAN_DAY;
847 		++strp;
848 		strp = getnum(strp, &rulep->r_day, 1, DAYSPERNYEAR);
849 	} else if (*strp == 'M') {
850 		/*
851 		** Month, week, day.
852 		*/
853 		rulep->r_type = MONTH_NTH_DAY_OF_WEEK;
854 		++strp;
855 		strp = getnum(strp, &rulep->r_mon, 1, MONSPERYEAR);
856 		if (strp == NULL)
857 			return NULL;
858 		if (*strp++ != '.')
859 			return NULL;
860 		strp = getnum(strp, &rulep->r_week, 1, 5);
861 		if (strp == NULL)
862 			return NULL;
863 		if (*strp++ != '.')
864 			return NULL;
865 		strp = getnum(strp, &rulep->r_day, 0, DAYSPERWEEK - 1);
866 	} else if (is_digit(*strp)) {
867 		/*
868 		** Day of year.
869 		*/
870 		rulep->r_type = DAY_OF_YEAR;
871 		strp = getnum(strp, &rulep->r_day, 0, DAYSPERLYEAR - 1);
872 	} else	return NULL;		/* invalid format */
873 	if (strp == NULL)
874 		return NULL;
875 	if (*strp == '/') {
876 		/*
877 		** Time specified.
878 		*/
879 		++strp;
880 		strp = getoffset(strp, &rulep->r_time);
881 	} else	rulep->r_time = 2 * SECSPERHOUR;	/* default = 2:00:00 */
882 	return strp;
883 }
884 
885 /*
886 ** Given a year, a rule, and the offset from UT at the time that rule takes
887 ** effect, calculate the year-relative time that rule takes effect.
888 */
889 
890 static int_fast32_t
891 transtime(const int year, const struct rule *const rulep,
892 	  const int_fast32_t offset)
893 {
894 	int	leapyear;
895 	int_fast32_t	value;
896 	int	i;
897 	int		d, m1, yy0, yy1, yy2, dow;
898 
899 	INITIALIZE(value);
900 	leapyear = isleap(year);
901 	switch (rulep->r_type) {
902 
903 	case JULIAN_DAY:
904 		/*
905 		** Jn - Julian day, 1 == January 1, 60 == March 1 even in leap
906 		** years.
907 		** In non-leap years, or if the day number is 59 or less, just
908 		** add SECSPERDAY times the day number-1 to the time of
909 		** January 1, midnight, to get the day.
910 		*/
911 		value = (rulep->r_day - 1) * SECSPERDAY;
912 		if (leapyear && rulep->r_day >= 60)
913 			value += SECSPERDAY;
914 		break;
915 
916 	case DAY_OF_YEAR:
917 		/*
918 		** n - day of year.
919 		** Just add SECSPERDAY times the day number to the time of
920 		** January 1, midnight, to get the day.
921 		*/
922 		value = rulep->r_day * SECSPERDAY;
923 		break;
924 
925 	case MONTH_NTH_DAY_OF_WEEK:
926 		/*
927 		** Mm.n.d - nth "dth day" of month m.
928 		*/
929 
930 		/*
931 		** Use Zeller's Congruence to get day-of-week of first day of
932 		** month.
933 		*/
934 		m1 = (rulep->r_mon + 9) % 12 + 1;
935 		yy0 = (rulep->r_mon <= 2) ? (year - 1) : year;
936 		yy1 = yy0 / 100;
937 		yy2 = yy0 % 100;
938 		dow = ((26 * m1 - 2) / 10 +
939 			1 + yy2 + yy2 / 4 + yy1 / 4 - 2 * yy1) % 7;
940 		if (dow < 0)
941 			dow += DAYSPERWEEK;
942 
943 		/*
944 		** "dow" is the day-of-week of the first day of the month. Get
945 		** the day-of-month (zero-origin) of the first "dow" day of the
946 		** month.
947 		*/
948 		d = rulep->r_day - dow;
949 		if (d < 0)
950 			d += DAYSPERWEEK;
951 		for (i = 1; i < rulep->r_week; ++i) {
952 			if (d + DAYSPERWEEK >=
953 				mon_lengths[leapyear][rulep->r_mon - 1])
954 					break;
955 			d += DAYSPERWEEK;
956 		}
957 
958 		/*
959 		** "d" is the day-of-month (zero-origin) of the day we want.
960 		*/
961 		value = d * SECSPERDAY;
962 		for (i = 0; i < rulep->r_mon - 1; ++i)
963 			value += mon_lengths[leapyear][i] * SECSPERDAY;
964 		break;
965 	}
966 
967 	/*
968 	** "value" is the year-relative time of 00:00:00 UT on the day in
969 	** question. To get the year-relative time of the specified local
970 	** time on that day, add the transition time and the current offset
971 	** from UT.
972 	*/
973 	return value + rulep->r_time + offset;
974 }
975 
976 /*
977 ** Given a POSIX section 8-style TZ string, fill in the rule tables as
978 ** appropriate.
979 */
980 
981 static int
982 tzparse(timezone_t sp, const char *name, const int lastditch)
983 {
984 	const char *		stdname;
985 	const char *		dstname;
986 	size_t			stdlen;
987 	size_t			dstlen;
988 	int_fast32_t		stdoffset;
989 	int_fast32_t		dstoffset;
990 	char *			cp;
991 	int			load_result;
992 
993 	dstname = NULL; /* XXX gcc */
994 	stdname = name;
995 	if (lastditch) {
996 		stdlen = strlen(name);	/* length of standard zone name */
997 		name += stdlen;
998 		if (stdlen >= sizeof sp->chars)
999 			stdlen = (sizeof sp->chars) - 1;
1000 		stdoffset = 0;
1001 	} else {
1002 		if (*name == '<') {
1003 			name++;
1004 			stdname = name;
1005 			name = getqzname(name, '>');
1006 			if (*name != '>')
1007 				return (-1);
1008 			stdlen = name - stdname;
1009 			name++;
1010 		} else {
1011 			name = getzname(name);
1012 			stdlen = name - stdname;
1013 		}
1014 		if (*name == '\0')
1015 			return -1;
1016 		name = getoffset(name, &stdoffset);
1017 		if (name == NULL)
1018 			return -1;
1019 	}
1020 	load_result = tzload(sp, TZDEFRULES, FALSE);
1021 	if (load_result != 0)
1022 		sp->leapcnt = 0;		/* so, we're off a little */
1023 	if (*name != '\0') {
1024 		if (*name == '<') {
1025 			dstname = ++name;
1026 			name = getqzname(name, '>');
1027 			if (*name != '>')
1028 				return -1;
1029 			dstlen = name - dstname;
1030 			name++;
1031 		} else {
1032 			dstname = name;
1033 			name = getzname(name);
1034 			dstlen = name - dstname; /* length of DST zone name */
1035 		}
1036 		if (*name != '\0' && *name != ',' && *name != ';') {
1037 			name = getoffset(name, &dstoffset);
1038 			if (name == NULL)
1039 				return -1;
1040 		} else	dstoffset = stdoffset - SECSPERHOUR;
1041 		if (*name == '\0' && load_result != 0)
1042 			name = TZDEFRULESTRING;
1043 		if (*name == ',' || *name == ';') {
1044 			struct rule	start;
1045 			struct rule	end;
1046 			int		year;
1047 			int		yearlim;
1048 			int		timecnt;
1049 			time_t		janfirst;
1050 
1051 			++name;
1052 			if ((name = getrule(name, &start)) == NULL)
1053 				return -1;
1054 			if (*name++ != ',')
1055 				return -1;
1056 			if ((name = getrule(name, &end)) == NULL)
1057 				return -1;
1058 			if (*name != '\0')
1059 				return -1;
1060 			sp->typecnt = 2;	/* standard time and DST */
1061 			/*
1062 			** Two transitions per year, from EPOCH_YEAR forward.
1063 			*/
1064 			memset(sp->ttis, 0, sizeof(sp->ttis));
1065 			sp->ttis[0].tt_gmtoff = -dstoffset;
1066 			sp->ttis[0].tt_isdst = 1;
1067 			sp->ttis[0].tt_abbrind = (int)(stdlen + 1);
1068 			sp->ttis[1].tt_gmtoff = -stdoffset;
1069 			sp->ttis[1].tt_isdst = 0;
1070 			sp->ttis[1].tt_abbrind = 0;
1071 			sp->defaulttype = 0;
1072 			timecnt = 0;
1073 			janfirst = 0;
1074 			sp->timecnt = 0;
1075 			yearlim = EPOCH_YEAR + YEARSPERREPEAT;
1076 			for (year = EPOCH_YEAR; year < yearlim; year++) {
1077 				int_fast32_t
1078 				  starttime = transtime(year, &start, stdoffset),
1079 				  endtime = transtime(year, &end, dstoffset);
1080 				int_fast32_t
1081 				  yearsecs = (year_lengths[isleap(year)]
1082 					      * SECSPERDAY);
1083 				int reversed = endtime < starttime;
1084 				if (reversed) {
1085 					int_fast32_t swap = starttime;
1086 					starttime = endtime;
1087 					endtime = swap;
1088 				}
1089 				if (reversed
1090 				    || (starttime < endtime
1091 					&& (endtime - starttime
1092 					    < (yearsecs
1093 					       + (stdoffset - dstoffset))))) {
1094 					if (TZ_MAX_TIMES - 2 < timecnt)
1095 						break;
1096 					yearlim = year + YEARSPERREPEAT + 1;
1097 					sp->ats[timecnt] = janfirst;
1098 					if (increment_overflow_time
1099 					    (&sp->ats[timecnt], starttime))
1100 						break;
1101 					sp->types[timecnt++] = reversed;
1102 					sp->ats[timecnt] = janfirst;
1103 					if (increment_overflow_time
1104 					    (&sp->ats[timecnt], endtime))
1105 						break;
1106 					sp->types[timecnt++] = !reversed;
1107 				}
1108 				if (increment_overflow_time(&janfirst, yearsecs))
1109 					break;
1110 			}
1111 			sp->timecnt = timecnt;
1112 			if (!timecnt)
1113 				sp->typecnt = 1;	/* Perpetual DST.  */
1114 		} else {
1115 			int_fast32_t	theirstdoffset;
1116 			int_fast32_t	theirdstoffset;
1117 			int_fast32_t	theiroffset;
1118 			int		isdst;
1119 			int		i;
1120 			int		j;
1121 
1122 			if (*name != '\0')
1123 				return -1;
1124 			/*
1125 			** Initial values of theirstdoffset and theirdstoffset.
1126 			*/
1127 			theirstdoffset = 0;
1128 			for (i = 0; i < sp->timecnt; ++i) {
1129 				j = sp->types[i];
1130 				if (!sp->ttis[j].tt_isdst) {
1131 					theirstdoffset =
1132 						-sp->ttis[j].tt_gmtoff;
1133 					break;
1134 				}
1135 			}
1136 			theirdstoffset = 0;
1137 			for (i = 0; i < sp->timecnt; ++i) {
1138 				j = sp->types[i];
1139 				if (sp->ttis[j].tt_isdst) {
1140 					theirdstoffset =
1141 						-sp->ttis[j].tt_gmtoff;
1142 					break;
1143 				}
1144 			}
1145 			/*
1146 			** Initially we're assumed to be in standard time.
1147 			*/
1148 			isdst = FALSE;
1149 			theiroffset = theirstdoffset;
1150 			/*
1151 			** Now juggle transition times and types
1152 			** tracking offsets as you do.
1153 			*/
1154 			for (i = 0; i < sp->timecnt; ++i) {
1155 				j = sp->types[i];
1156 				sp->types[i] = sp->ttis[j].tt_isdst;
1157 				if (sp->ttis[j].tt_ttisgmt) {
1158 					/* No adjustment to transition time */
1159 				} else {
1160 					/*
1161 					** If summer time is in effect, and the
1162 					** transition time was not specified as
1163 					** standard time, add the summer time
1164 					** offset to the transition time;
1165 					** otherwise, add the standard time
1166 					** offset to the transition time.
1167 					*/
1168 					/*
1169 					** Transitions from DST to DDST
1170 					** will effectively disappear since
1171 					** POSIX provides for only one DST
1172 					** offset.
1173 					*/
1174 					if (isdst && !sp->ttis[j].tt_ttisstd) {
1175 						sp->ats[i] += (time_t)
1176 						    (dstoffset - theirdstoffset);
1177 					} else {
1178 						sp->ats[i] += (time_t)
1179 						    (stdoffset - theirstdoffset);
1180 					}
1181 				}
1182 				theiroffset = -sp->ttis[j].tt_gmtoff;
1183 				if (!sp->ttis[j].tt_isdst)
1184 					theirstdoffset = theiroffset;
1185 				else	theirdstoffset = theiroffset;
1186 			}
1187 			/*
1188 			** Finally, fill in ttis.
1189 			** ttisstd and ttisgmt need not be handled
1190 			*/
1191 			memset(sp->ttis, 0, sizeof(sp->ttis));
1192 			sp->ttis[0].tt_gmtoff = -stdoffset;
1193 			sp->ttis[0].tt_isdst = FALSE;
1194 			sp->ttis[0].tt_abbrind = 0;
1195 			sp->ttis[1].tt_gmtoff = -dstoffset;
1196 			sp->ttis[1].tt_isdst = TRUE;
1197 			sp->ttis[1].tt_abbrind = (int)(stdlen + 1);
1198 			sp->typecnt = 2;
1199 			sp->defaulttype = 0;
1200 		}
1201 	} else {
1202 		dstlen = 0;
1203 		sp->typecnt = 1;		/* only standard time */
1204 		sp->timecnt = 0;
1205 		memset(sp->ttis, 0, sizeof(sp->ttis));
1206 		sp->ttis[0].tt_gmtoff = -stdoffset;
1207 		sp->ttis[0].tt_isdst = 0;
1208 		sp->ttis[0].tt_abbrind = 0;
1209 		sp->defaulttype = 0;
1210 	}
1211 	sp->charcnt = (int)(stdlen + 1);
1212 	if (dstlen != 0)
1213 		sp->charcnt += (int)(dstlen + 1);
1214 	if ((size_t) sp->charcnt > sizeof sp->chars)
1215 		return -1;
1216 	cp = sp->chars;
1217 	(void) strncpy(cp, stdname, stdlen);
1218 	cp += stdlen;
1219 	*cp++ = '\0';
1220 	if (dstlen != 0) {
1221 		(void) strncpy(cp, dstname, dstlen);
1222 		*(cp + dstlen) = '\0';
1223 	}
1224 	return 0;
1225 }
1226 
1227 static void
1228 gmtload(timezone_t sp)
1229 {
1230 	if (tzload(sp, gmt, TRUE) != 0)
1231 		(void) tzparse(sp, gmt, TRUE);
1232 }
1233 
1234 timezone_t
1235 tzalloc(const char *name)
1236 {
1237 	timezone_t sp = malloc(sizeof *sp);
1238 	if (sp == NULL)
1239 		return NULL;
1240 	if (tzload(sp, name, TRUE) != 0) {
1241 		free(sp);
1242 		return NULL;
1243 	}
1244 	settzname_z(sp);
1245 	return sp;
1246 }
1247 
1248 void
1249 tzfree(const timezone_t sp)
1250 {
1251 	free(sp);
1252 }
1253 
1254 static void
1255 tzsetwall_unlocked(void)
1256 {
1257 	if (lcl_is_set < 0)
1258 		return;
1259 	lcl_is_set = -1;
1260 
1261 	if (lclptr == NULL) {
1262 		int saveerrno = errno;
1263 		lclptr = malloc(sizeof *lclptr);
1264 		errno = saveerrno;
1265 		if (lclptr == NULL) {
1266 			settzname();	/* all we can do */
1267 			return;
1268 		}
1269 	}
1270 	if (tzload(lclptr, NULL, TRUE) != 0)
1271 		gmtload(lclptr);
1272 	settzname();
1273 }
1274 
1275 #ifndef STD_INSPIRED
1276 /*
1277 ** A non-static declaration of tzsetwall in a system header file
1278 ** may cause a warning about this upcoming static declaration...
1279 */
1280 static
1281 #endif /* !defined STD_INSPIRED */
1282 void
1283 tzsetwall(void)
1284 {
1285 	rwlock_wrlock(&lcl_lock);
1286 	tzsetwall_unlocked();
1287 	rwlock_unlock(&lcl_lock);
1288 }
1289 
1290 #ifndef STD_INSPIRED
1291 /*
1292 ** A non-static declaration of tzsetwall in a system header file
1293 ** may cause a warning about this upcoming static declaration...
1294 */
1295 static
1296 #endif /* !defined STD_INSPIRED */
1297 void
1298 tzset_unlocked(void)
1299 {
1300 	const char *	name;
1301 
1302 	name = getenv("TZ");
1303 	if (name == NULL) {
1304 		tzsetwall_unlocked();
1305 		return;
1306 	}
1307 
1308 	if (lcl_is_set > 0 && strcmp(lcl_TZname, name) == 0)
1309 		return;
1310 	lcl_is_set = strlen(name) < sizeof lcl_TZname;
1311 	if (lcl_is_set)
1312 		(void)strlcpy(lcl_TZname, name, sizeof(lcl_TZname));
1313 
1314 	if (lclptr == NULL) {
1315 		int saveerrno = errno;
1316 		lclptr = malloc(sizeof *lclptr);
1317 		errno = saveerrno;
1318 		if (lclptr == NULL) {
1319 			settzname();	/* all we can do */
1320 			return;
1321 		}
1322 	}
1323 	if (*name == '\0') {
1324 		/*
1325 		** User wants it fast rather than right.
1326 		*/
1327 		lclptr->leapcnt = 0;		/* so, we're off a little */
1328 		lclptr->timecnt = 0;
1329 		lclptr->typecnt = 0;
1330 		lclptr->ttis[0].tt_isdst = 0;
1331 		lclptr->ttis[0].tt_gmtoff = 0;
1332 		lclptr->ttis[0].tt_abbrind = 0;
1333 		(void) strlcpy(lclptr->chars, gmt, sizeof(lclptr->chars));
1334 	} else if (tzload(lclptr, name, TRUE) != 0)
1335 		if (name[0] == ':' || tzparse(lclptr, name, FALSE) != 0)
1336 			(void) gmtload(lclptr);
1337 	settzname();
1338 }
1339 
1340 void
1341 tzset(void)
1342 {
1343 	rwlock_wrlock(&lcl_lock);
1344 	tzset_unlocked();
1345 	rwlock_unlock(&lcl_lock);
1346 }
1347 
1348 /*
1349 ** The easy way to behave "as if no library function calls" localtime
1350 ** is to not call it, so we drop its guts into "localsub", which can be
1351 ** freely called. (And no, the PANS doesn't require the above behavior,
1352 ** but it *is* desirable.)
1353 **
1354 ** The unused offset argument is for the benefit of mktime variants.
1355 */
1356 
1357 /*ARGSUSED*/
1358 static struct tm *
1359 localsub(const timezone_t sp, const time_t * const timep, const int_fast32_t offset,
1360     struct tm *const tmp)
1361 {
1362 	const struct ttinfo *	ttisp;
1363 	int			i;
1364 	struct tm *		result;
1365 	const time_t			t = *timep;
1366 
1367 	if ((sp->goback && t < sp->ats[0]) ||
1368 		(sp->goahead && t > sp->ats[sp->timecnt - 1])) {
1369 			time_t			newt = t;
1370 			time_t		seconds;
1371 			time_t		years;
1372 
1373 			if (t < sp->ats[0])
1374 				seconds = sp->ats[0] - t;
1375 			else	seconds = t - sp->ats[sp->timecnt - 1];
1376 			--seconds;
1377 			years = (time_t)((seconds / SECSPERREPEAT + 1) * YEARSPERREPEAT);
1378 			seconds = (time_t)(years * AVGSECSPERYEAR);
1379 			if (t < sp->ats[0])
1380 				newt += seconds;
1381 			else	newt -= seconds;
1382 			if (newt < sp->ats[0] ||
1383 				newt > sp->ats[sp->timecnt - 1])
1384 					return NULL;	/* "cannot happen" */
1385 			result = localsub(sp, &newt, offset, tmp);
1386 			if (result == tmp) {
1387 				time_t	newy;
1388 
1389 				newy = tmp->tm_year;
1390 				if (t < sp->ats[0])
1391 					newy -= years;
1392 				else	newy += years;
1393 				tmp->tm_year = (int)newy;
1394 				if (tmp->tm_year != newy)
1395 					return NULL;
1396 			}
1397 			return result;
1398 	}
1399 	if (sp->timecnt == 0 || t < sp->ats[0]) {
1400 		i = sp->defaulttype;
1401 	} else {
1402 		int	lo = 1;
1403 		int	hi = sp->timecnt;
1404 
1405 		while (lo < hi) {
1406 			int	mid = (lo + hi) / 2;
1407 
1408 			if (t < sp->ats[mid])
1409 				hi = mid;
1410 			else	lo = mid + 1;
1411 		}
1412 		i = (int) sp->types[lo - 1];
1413 	}
1414 	ttisp = &sp->ttis[i];
1415 	/*
1416 	** To get (wrong) behavior that's compatible with System V Release 2.0
1417 	** you'd replace the statement below with
1418 	**	t += ttisp->tt_gmtoff;
1419 	**	timesub(&t, 0L, sp, tmp);
1420 	*/
1421 	result = timesub(sp, &t, ttisp->tt_gmtoff, tmp);
1422 	tmp->tm_isdst = ttisp->tt_isdst;
1423 	if (sp == lclptr)
1424 		tzname[tmp->tm_isdst] = &sp->chars[ttisp->tt_abbrind];
1425 #ifdef TM_ZONE
1426 	tmp->TM_ZONE = &sp->chars[ttisp->tt_abbrind];
1427 #endif /* defined TM_ZONE */
1428 	return result;
1429 }
1430 
1431 /*
1432 ** Re-entrant version of localtime.
1433 */
1434 
1435 struct tm *
1436 localtime_r(const time_t * __restrict timep, struct tm *tmp)
1437 {
1438 	rwlock_rdlock(&lcl_lock);
1439 	tzset_unlocked();
1440 	tmp = localtime_rz(lclptr, timep, tmp);
1441 	rwlock_unlock(&lcl_lock);
1442 	return tmp;
1443 }
1444 
1445 struct tm *
1446 localtime(const time_t *const timep)
1447 {
1448 	return localtime_r(timep, &tm);
1449 }
1450 
1451 struct tm *
1452 localtime_rz(const timezone_t sp, const time_t * __restrict timep, struct tm *tmp)
1453 {
1454 	if (sp == NULL)
1455 		tmp = gmtsub(NULL, timep, 0, tmp);
1456 	else
1457 		tmp = localsub(sp, timep, 0, tmp);
1458 	if (tmp == NULL)
1459 		errno = EOVERFLOW;
1460 	return tmp;
1461 }
1462 
1463 /*
1464 ** gmtsub is to gmtime as localsub is to localtime.
1465 */
1466 
1467 static struct tm *
1468 gmtsub(const timezone_t sp, const time_t *const timep,
1469     const int_fast32_t offset, struct tm *const tmp)
1470 {
1471 	struct tm *	result;
1472 #ifdef _REENTRANT
1473 	static mutex_t gmt_mutex = MUTEX_INITIALIZER;
1474 #endif
1475 
1476 	mutex_lock(&gmt_mutex);
1477 	if (!gmt_is_set) {
1478 		int saveerrno;
1479 		gmt_is_set = TRUE;
1480 		saveerrno = errno;
1481 		gmtptr = malloc(sizeof *gmtptr);
1482 		gmt_is_set = gmtptr != NULL;
1483 		errno = saveerrno;
1484 		if (gmt_is_set)
1485 			gmtload(gmtptr);
1486 	}
1487 	mutex_unlock(&gmt_mutex);
1488 	result = timesub(gmtptr, timep, offset, tmp);
1489 #ifdef TM_ZONE
1490 	/*
1491 	** Could get fancy here and deliver something such as
1492 	** "UT+xxxx" or "UT-xxxx" if offset is non-zero,
1493 	** but this is no time for a treasure hunt.
1494 	*/
1495 	tmp->TM_ZONE = offset ? __UNCONST(wildabbr) : gmtptr ? gmtptr->chars :
1496 	    __UNCONST(gmt);
1497 #endif /* defined TM_ZONE */
1498 	return result;
1499 }
1500 
1501 struct tm *
1502 gmtime(const time_t *const timep)
1503 {
1504 	struct tm *tmp = gmtsub(NULL, timep, 0, &tm);
1505 
1506 	if (tmp == NULL)
1507 		errno = EOVERFLOW;
1508 
1509 	return tmp;
1510 }
1511 
1512 /*
1513 ** Re-entrant version of gmtime.
1514 */
1515 
1516 struct tm *
1517 gmtime_r(const time_t * const timep, struct tm *tmp)
1518 {
1519 	tmp = gmtsub(NULL, timep, 0, tmp);
1520 
1521 	if (tmp == NULL)
1522 		errno = EOVERFLOW;
1523 
1524 	return tmp;
1525 }
1526 
1527 #ifdef STD_INSPIRED
1528 
1529 struct tm *
1530 offtime(const time_t *const timep, long offset)
1531 {
1532 	struct tm *tmp;
1533 
1534 	if ((offset > 0 && offset > INT_FAST32_MAX) ||
1535 	    (offset < 0 && offset < INT_FAST32_MIN)) {
1536 		errno = EOVERFLOW;
1537 		return NULL;
1538 	}
1539 	tmp = gmtsub(NULL, timep, (int_fast32_t)offset, &tm);
1540 
1541 	if (tmp == NULL)
1542 		errno = EOVERFLOW;
1543 
1544 	return tmp;
1545 }
1546 
1547 struct tm *
1548 offtime_r(const time_t *timep, long offset, struct tm *tmp)
1549 {
1550 	if ((offset > 0 && offset > INT_FAST32_MAX) ||
1551 	    (offset < 0 && offset < INT_FAST32_MIN)) {
1552 		errno = EOVERFLOW;
1553 		return NULL;
1554 	}
1555 	tmp = gmtsub(NULL, timep, (int_fast32_t)offset, tmp);
1556 
1557 	if (tmp == NULL)
1558 		errno = EOVERFLOW;
1559 
1560 	return tmp;
1561 }
1562 
1563 #endif /* defined STD_INSPIRED */
1564 
1565 /*
1566 ** Return the number of leap years through the end of the given year
1567 ** where, to make the math easy, the answer for year zero is defined as zero.
1568 */
1569 
1570 static int
1571 leaps_thru_end_of(const int y)
1572 {
1573 	return (y >= 0) ? (y / 4 - y / 100 + y / 400) :
1574 		-(leaps_thru_end_of(-(y + 1)) + 1);
1575 }
1576 
1577 static struct tm *
1578 timesub(const timezone_t sp, const time_t *const timep,
1579     const int_fast32_t offset, struct tm *const tmp)
1580 {
1581 	const struct lsinfo *	lp;
1582 	time_t			tdays;
1583 	int			idays;	/* unsigned would be so 2003 */
1584 	int_fast64_t		rem;
1585 	int			y;
1586 	const int *		ip;
1587 	int_fast64_t		corr;
1588 	int			hit;
1589 	int			i;
1590 
1591 	corr = 0;
1592 	hit = 0;
1593 	i = (sp == NULL) ? 0 : sp->leapcnt;
1594 	while (--i >= 0) {
1595 		lp = &sp->lsis[i];
1596 		if (*timep >= lp->ls_trans) {
1597 			if (*timep == lp->ls_trans) {
1598 				hit = ((i == 0 && lp->ls_corr > 0) ||
1599 					lp->ls_corr > sp->lsis[i - 1].ls_corr);
1600 				if (hit)
1601 					while (i > 0 &&
1602 						sp->lsis[i].ls_trans ==
1603 						sp->lsis[i - 1].ls_trans + 1 &&
1604 						sp->lsis[i].ls_corr ==
1605 						sp->lsis[i - 1].ls_corr + 1) {
1606 							++hit;
1607 							--i;
1608 					}
1609 			}
1610 			corr = lp->ls_corr;
1611 			break;
1612 		}
1613 	}
1614 	y = EPOCH_YEAR;
1615 	tdays = (time_t)(*timep / SECSPERDAY);
1616 	rem = (int_fast64_t) (*timep - tdays * SECSPERDAY);
1617 	while (tdays < 0 || tdays >= year_lengths[isleap(y)]) {
1618 		int		newy;
1619 		time_t	tdelta;
1620 		int	idelta;
1621 		int	leapdays;
1622 
1623 		tdelta = tdays / DAYSPERLYEAR;
1624 		if (! ((! TYPE_SIGNED(time_t) || INT_MIN <= tdelta)
1625 		       && tdelta <= INT_MAX))
1626 			return NULL;
1627 		_DIAGASSERT(__type_fit(int, tdelta));
1628 		idelta = (int)tdelta;
1629 		if (idelta == 0)
1630 			idelta = (tdays < 0) ? -1 : 1;
1631 		newy = y;
1632 		if (increment_overflow(&newy, idelta))
1633 			return NULL;
1634 		leapdays = leaps_thru_end_of(newy - 1) -
1635 			leaps_thru_end_of(y - 1);
1636 		tdays -= ((time_t) newy - y) * DAYSPERNYEAR;
1637 		tdays -= leapdays;
1638 		y = newy;
1639 	}
1640 	{
1641 		int_fast32_t seconds;
1642 
1643 		seconds = (int_fast32_t)(tdays * SECSPERDAY);
1644 		tdays = (time_t)(seconds / SECSPERDAY);
1645 		rem += (int_fast64_t)(seconds - tdays * SECSPERDAY);
1646 	}
1647 	/*
1648 	** Given the range, we can now fearlessly cast...
1649 	*/
1650 	idays = (int) tdays;
1651 	rem += offset - corr;
1652 	while (rem < 0) {
1653 		rem += SECSPERDAY;
1654 		--idays;
1655 	}
1656 	while (rem >= SECSPERDAY) {
1657 		rem -= SECSPERDAY;
1658 		++idays;
1659 	}
1660 	while (idays < 0) {
1661 		if (increment_overflow(&y, -1))
1662 			return NULL;
1663 		idays += year_lengths[isleap(y)];
1664 	}
1665 	while (idays >= year_lengths[isleap(y)]) {
1666 		idays -= year_lengths[isleap(y)];
1667 		if (increment_overflow(&y, 1))
1668 			return NULL;
1669 	}
1670 	tmp->tm_year = y;
1671 	if (increment_overflow(&tmp->tm_year, -TM_YEAR_BASE))
1672 		return NULL;
1673 	tmp->tm_yday = idays;
1674 	/*
1675 	** The "extra" mods below avoid overflow problems.
1676 	*/
1677 	tmp->tm_wday = EPOCH_WDAY +
1678 		((y - EPOCH_YEAR) % DAYSPERWEEK) *
1679 		(DAYSPERNYEAR % DAYSPERWEEK) +
1680 		leaps_thru_end_of(y - 1) -
1681 		leaps_thru_end_of(EPOCH_YEAR - 1) +
1682 		idays;
1683 	tmp->tm_wday %= DAYSPERWEEK;
1684 	if (tmp->tm_wday < 0)
1685 		tmp->tm_wday += DAYSPERWEEK;
1686 	tmp->tm_hour = (int) (rem / SECSPERHOUR);
1687 	rem %= SECSPERHOUR;
1688 	tmp->tm_min = (int) (rem / SECSPERMIN);
1689 	/*
1690 	** A positive leap second requires a special
1691 	** representation. This uses "... ??:59:60" et seq.
1692 	*/
1693 	tmp->tm_sec = (int) (rem % SECSPERMIN) + hit;
1694 	ip = mon_lengths[isleap(y)];
1695 	for (tmp->tm_mon = 0; idays >= ip[tmp->tm_mon]; ++(tmp->tm_mon))
1696 		idays -= ip[tmp->tm_mon];
1697 	tmp->tm_mday = (int) (idays + 1);
1698 	tmp->tm_isdst = 0;
1699 #ifdef TM_GMTOFF
1700 	tmp->TM_GMTOFF = offset;
1701 #endif /* defined TM_GMTOFF */
1702 	return tmp;
1703 }
1704 
1705 char *
1706 ctime(const time_t *const timep)
1707 {
1708 /*
1709 ** Section 4.12.3.2 of X3.159-1989 requires that
1710 **	The ctime function converts the calendar time pointed to by timer
1711 **	to local time in the form of a string. It is equivalent to
1712 **		asctime(localtime(timer))
1713 */
1714 	struct tm *rtm = localtime(timep);
1715 	if (rtm == NULL)
1716 		return NULL;
1717 	return asctime(rtm);
1718 }
1719 
1720 char *
1721 ctime_r(const time_t *const timep, char *buf)
1722 {
1723 	struct tm	mytm, *rtm;
1724 
1725 	rtm = localtime_r(timep, &mytm);
1726 	if (rtm == NULL)
1727 		return NULL;
1728 	return asctime_r(rtm, buf);
1729 }
1730 
1731 char *
1732 ctime_rz(const timezone_t sp, const time_t * timep, char *buf)
1733 {
1734 	struct tm	mytm, *rtm;
1735 
1736 	rtm = localtime_rz(sp, timep, &mytm);
1737 	if (rtm == NULL)
1738 		return NULL;
1739 	return asctime_r(rtm, buf);
1740 }
1741 
1742 /*
1743 ** Adapted from code provided by Robert Elz, who writes:
1744 **	The "best" way to do mktime I think is based on an idea of Bob
1745 **	Kridle's (so its said...) from a long time ago.
1746 **	It does a binary search of the time_t space. Since time_t's are
1747 **	just 32 bits, its a max of 32 iterations (even at 64 bits it
1748 **	would still be very reasonable).
1749 */
1750 
1751 #ifndef WRONG
1752 #define WRONG	((time_t)-1)
1753 #endif /* !defined WRONG */
1754 
1755 /*
1756 ** Simplified normalize logic courtesy Paul Eggert.
1757 */
1758 
1759 static int
1760 increment_overflow(int *const ip, int j)
1761 {
1762 	int	i = *ip;
1763 
1764 	/*
1765 	** If i >= 0 there can only be overflow if i + j > INT_MAX
1766 	** or if j > INT_MAX - i; given i >= 0, INT_MAX - i cannot overflow.
1767 	** If i < 0 there can only be overflow if i + j < INT_MIN
1768 	** or if j < INT_MIN - i; given i < 0, INT_MIN - i cannot overflow.
1769 	*/
1770 	if ((i >= 0) ? (j > INT_MAX - i) : (j < INT_MIN - i))
1771 		return TRUE;
1772 	*ip += j;
1773 	return FALSE;
1774 }
1775 
1776 static int
1777 increment_overflow32(int_fast32_t *const lp, int const m)
1778 {
1779 	int_fast32_t l = *lp;
1780 
1781 	if ((l >= 0) ? (m > INT_FAST32_MAX - l) : (m < INT_FAST32_MIN - l))
1782 		return TRUE;
1783 	*lp += m;
1784 	return FALSE;
1785 }
1786 
1787 static int
1788 increment_overflow_time(time_t *tp, int_fast32_t j)
1789 {
1790 	/*
1791 	** This is like
1792 	** 'if (! (time_t_min <= *tp + j && *tp + j <= time_t_max)) ...',
1793 	** except that it does the right thing even if *tp + j would overflow.
1794 	*/
1795 	if (! (j < 0
1796 	       ? (TYPE_SIGNED(time_t) ? time_t_min - j <= *tp : -1 - j < *tp)
1797 	       : *tp <= time_t_max - j))
1798 		return TRUE;
1799 	*tp += j;
1800 	return FALSE;
1801 }
1802 
1803 static int
1804 normalize_overflow(int *const tensptr, int *const unitsptr, const int base)
1805 {
1806 	int	tensdelta;
1807 
1808 	tensdelta = (*unitsptr >= 0) ?
1809 		(*unitsptr / base) :
1810 		(-1 - (-1 - *unitsptr) / base);
1811 	*unitsptr -= tensdelta * base;
1812 	return increment_overflow(tensptr, tensdelta);
1813 }
1814 
1815 static int
1816 normalize_overflow32(int_fast32_t *const tensptr, int *const unitsptr,
1817     const int base)
1818 {
1819 	int	tensdelta;
1820 
1821 	tensdelta = (*unitsptr >= 0) ?
1822 		(*unitsptr / base) :
1823 		(-1 - (-1 - *unitsptr) / base);
1824 	*unitsptr -= tensdelta * base;
1825 	return increment_overflow32(tensptr, tensdelta);
1826 }
1827 
1828 static int
1829 tmcomp(const struct tm *const atmp, const struct tm *const btmp)
1830 {
1831 	int	result;
1832 
1833 	if (atmp->tm_year != btmp->tm_year)
1834 		return atmp->tm_year < btmp->tm_year ? -1 : 1;
1835 	if ((result = (atmp->tm_mon - btmp->tm_mon)) == 0 &&
1836 		(result = (atmp->tm_mday - btmp->tm_mday)) == 0 &&
1837 		(result = (atmp->tm_hour - btmp->tm_hour)) == 0 &&
1838 		(result = (atmp->tm_min - btmp->tm_min)) == 0)
1839 			result = atmp->tm_sec - btmp->tm_sec;
1840 	return result;
1841 }
1842 
1843 static time_t
1844 time2sub(const timezone_t sp, struct tm *const tmp, subfun_t funcp,
1845     const int_fast32_t offset, int *const okayp, const int do_norm_secs)
1846 {
1847 	int			dir;
1848 	int			i, j;
1849 	int			saved_seconds;
1850 	int_fast32_t		li;
1851 	time_t			lo;
1852 	time_t			hi;
1853 #ifdef NO_ERROR_IN_DST_GAP
1854 	time_t			ilo;
1855 #endif
1856 	int_fast32_t		y;
1857 	time_t			newt;
1858 	time_t			t;
1859 	struct tm		yourtm, mytm;
1860 
1861 	*okayp = FALSE;
1862 	yourtm = *tmp;
1863 #ifdef NO_ERROR_IN_DST_GAP
1864 again:
1865 #endif
1866 	if (do_norm_secs) {
1867 		if (normalize_overflow(&yourtm.tm_min, &yourtm.tm_sec,
1868 		    SECSPERMIN))
1869 			goto overflow;
1870 	}
1871 	if (normalize_overflow(&yourtm.tm_hour, &yourtm.tm_min, MINSPERHOUR))
1872 		goto overflow;
1873 	if (normalize_overflow(&yourtm.tm_mday, &yourtm.tm_hour, HOURSPERDAY))
1874 		goto overflow;
1875 	y = yourtm.tm_year;
1876 	if (normalize_overflow32(&y, &yourtm.tm_mon, MONSPERYEAR))
1877 		goto overflow;
1878 	/*
1879 	** Turn y into an actual year number for now.
1880 	** It is converted back to an offset from TM_YEAR_BASE later.
1881 	*/
1882 	if (increment_overflow32(&y, TM_YEAR_BASE))
1883 		goto overflow;
1884 	while (yourtm.tm_mday <= 0) {
1885 		if (increment_overflow32(&y, -1))
1886 			goto overflow;
1887 		li = y + (1 < yourtm.tm_mon);
1888 		yourtm.tm_mday += year_lengths[isleap(li)];
1889 	}
1890 	while (yourtm.tm_mday > DAYSPERLYEAR) {
1891 		li = y + (1 < yourtm.tm_mon);
1892 		yourtm.tm_mday -= year_lengths[isleap(li)];
1893 		if (increment_overflow32(&y, 1))
1894 			goto overflow;
1895 	}
1896 	for ( ; ; ) {
1897 		i = mon_lengths[isleap(y)][yourtm.tm_mon];
1898 		if (yourtm.tm_mday <= i)
1899 			break;
1900 		yourtm.tm_mday -= i;
1901 		if (++yourtm.tm_mon >= MONSPERYEAR) {
1902 			yourtm.tm_mon = 0;
1903 			if (increment_overflow32(&y, 1))
1904 				goto overflow;
1905 		}
1906 	}
1907 	if (increment_overflow32(&y, -TM_YEAR_BASE))
1908 		goto overflow;
1909 	yourtm.tm_year = (int)y;
1910 	if (yourtm.tm_year != y)
1911 		goto overflow;
1912 	if (yourtm.tm_sec >= 0 && yourtm.tm_sec < SECSPERMIN)
1913 		saved_seconds = 0;
1914 	else if (y + TM_YEAR_BASE < EPOCH_YEAR) {
1915 		/*
1916 		** We can't set tm_sec to 0, because that might push the
1917 		** time below the minimum representable time.
1918 		** Set tm_sec to 59 instead.
1919 		** This assumes that the minimum representable time is
1920 		** not in the same minute that a leap second was deleted from,
1921 		** which is a safer assumption than using 58 would be.
1922 		*/
1923 		if (increment_overflow(&yourtm.tm_sec, 1 - SECSPERMIN))
1924 			goto overflow;
1925 		saved_seconds = yourtm.tm_sec;
1926 		yourtm.tm_sec = SECSPERMIN - 1;
1927 	} else {
1928 		saved_seconds = yourtm.tm_sec;
1929 		yourtm.tm_sec = 0;
1930 	}
1931 	/*
1932 	** Do a binary search (this works whatever time_t's type is).
1933 	*/
1934 	/* LINTED const not */
1935 	if (!TYPE_SIGNED(time_t)) {
1936 		lo = 0;
1937 		hi = lo - 1;
1938 	} else {
1939 		lo = 1;
1940 		for (i = 0; i < (int) TYPE_BIT(time_t) - 1; ++i)
1941 			lo *= 2;
1942 		hi = -(lo + 1);
1943 	}
1944 #ifdef NO_ERROR_IN_DST_GAP
1945 	ilo = lo;
1946 #endif
1947 	for ( ; ; ) {
1948 		t = lo / 2 + hi / 2;
1949 		if (t < lo)
1950 			t = lo;
1951 		else if (t > hi)
1952 			t = hi;
1953 		if ((*funcp)(sp, &t, offset, &mytm) == NULL) {
1954 			/*
1955 			** Assume that t is too extreme to be represented in
1956 			** a struct tm; arrange things so that it is less
1957 			** extreme on the next pass.
1958 			*/
1959 			dir = (t > 0) ? 1 : -1;
1960 		} else	dir = tmcomp(&mytm, &yourtm);
1961 		if (dir != 0) {
1962 			if (t == lo) {
1963 				if (t == time_t_max)
1964 					goto overflow;
1965 				++t;
1966 				++lo;
1967 			} else if (t == hi) {
1968 				if (t == time_t_min)
1969 					goto overflow;
1970 				--t;
1971 				--hi;
1972 			}
1973 #ifdef NO_ERROR_IN_DST_GAP
1974 			if (ilo != lo && lo - 1 == hi && yourtm.tm_isdst < 0 &&
1975 			    do_norm_secs) {
1976 				for (i = sp->typecnt - 1; i >= 0; --i) {
1977 					for (j = sp->typecnt - 1; j >= 0; --j) {
1978 						time_t off;
1979 						if (sp->ttis[j].tt_isdst ==
1980 						    sp->ttis[i].tt_isdst)
1981 							continue;
1982 						off = sp->ttis[j].tt_gmtoff -
1983 						    sp->ttis[i].tt_gmtoff;
1984 						yourtm.tm_sec += off < 0 ?
1985 						    -off : off;
1986 						goto again;
1987 					}
1988 				}
1989 			}
1990 #endif
1991 			if (lo > hi)
1992 				goto invalid;
1993 			if (dir > 0)
1994 				hi = t;
1995 			else	lo = t;
1996 			continue;
1997 		}
1998 		if (yourtm.tm_isdst < 0 || mytm.tm_isdst == yourtm.tm_isdst)
1999 			break;
2000 		/*
2001 		** Right time, wrong type.
2002 		** Hunt for right time, right type.
2003 		** It's okay to guess wrong since the guess
2004 		** gets checked.
2005 		*/
2006 		if (sp == NULL)
2007 			goto invalid;
2008 		for (i = sp->typecnt - 1; i >= 0; --i) {
2009 			if (sp->ttis[i].tt_isdst != yourtm.tm_isdst)
2010 				continue;
2011 			for (j = sp->typecnt - 1; j >= 0; --j) {
2012 				if (sp->ttis[j].tt_isdst == yourtm.tm_isdst)
2013 					continue;
2014 				newt = (time_t)(t + sp->ttis[j].tt_gmtoff -
2015 				    sp->ttis[i].tt_gmtoff);
2016 				if ((*funcp)(sp, &newt, offset, &mytm) == NULL)
2017 					continue;
2018 				if (tmcomp(&mytm, &yourtm) != 0)
2019 					continue;
2020 				if (mytm.tm_isdst != yourtm.tm_isdst)
2021 					continue;
2022 				/*
2023 				** We have a match.
2024 				*/
2025 				t = newt;
2026 				goto label;
2027 			}
2028 		}
2029 		goto invalid;
2030 	}
2031 label:
2032 	newt = t + saved_seconds;
2033 	if ((newt < t) != (saved_seconds < 0))
2034 		goto overflow;
2035 	t = newt;
2036 	if ((*funcp)(sp, &t, offset, tmp)) {
2037 		*okayp = TRUE;
2038 		return t;
2039 	}
2040 overflow:
2041 	errno = EOVERFLOW;
2042 	return WRONG;
2043 invalid:
2044 	errno = EINVAL;
2045 	return WRONG;
2046 }
2047 
2048 static time_t
2049 time2(const timezone_t sp, struct tm *const tmp, subfun_t funcp,
2050     const int_fast32_t offset, int *const okayp)
2051 {
2052 	time_t	t;
2053 
2054 	/*
2055 	** First try without normalization of seconds
2056 	** (in case tm_sec contains a value associated with a leap second).
2057 	** If that fails, try with normalization of seconds.
2058 	*/
2059 	t = time2sub(sp, tmp, funcp, offset, okayp, FALSE);
2060 	return *okayp ? t : time2sub(sp, tmp, funcp, offset, okayp, TRUE);
2061 }
2062 
2063 static time_t
2064 time1(const timezone_t sp, struct tm *const tmp, subfun_t funcp,
2065     const int_fast32_t offset)
2066 {
2067 	time_t			t;
2068 	int			samei, otheri;
2069 	int			sameind, otherind;
2070 	int			i;
2071 	int			nseen;
2072 	char				seen[TZ_MAX_TYPES];
2073 	unsigned char			types[TZ_MAX_TYPES];
2074 	int				okay;
2075 
2076 	if (tmp == NULL) {
2077 		errno = EINVAL;
2078 		return WRONG;
2079 	}
2080 	if (tmp->tm_isdst > 1)
2081 		tmp->tm_isdst = 1;
2082 	t = time2(sp, tmp, funcp, offset, &okay);
2083 	if (okay)
2084 		return t;
2085 	if (tmp->tm_isdst < 0)
2086 #ifdef PCTS
2087 		/*
2088 		** POSIX Conformance Test Suite code courtesy Grant Sullivan.
2089 		*/
2090 		tmp->tm_isdst = 0;	/* reset to std and try again */
2091 #else
2092 		return t;
2093 #endif /* !defined PCTS */
2094 	/*
2095 	** We're supposed to assume that somebody took a time of one type
2096 	** and did some math on it that yielded a "struct tm" that's bad.
2097 	** We try to divine the type they started from and adjust to the
2098 	** type they need.
2099 	*/
2100 	if (sp == NULL) {
2101 		errno = EINVAL;
2102 		return WRONG;
2103 	}
2104 	for (i = 0; i < sp->typecnt; ++i)
2105 		seen[i] = FALSE;
2106 	nseen = 0;
2107 	for (i = sp->timecnt - 1; i >= 0; --i)
2108 		if (!seen[sp->types[i]]) {
2109 			seen[sp->types[i]] = TRUE;
2110 			types[nseen++] = sp->types[i];
2111 		}
2112 	for (sameind = 0; sameind < nseen; ++sameind) {
2113 		samei = types[sameind];
2114 		if (sp->ttis[samei].tt_isdst != tmp->tm_isdst)
2115 			continue;
2116 		for (otherind = 0; otherind < nseen; ++otherind) {
2117 			otheri = types[otherind];
2118 			if (sp->ttis[otheri].tt_isdst == tmp->tm_isdst)
2119 				continue;
2120 			tmp->tm_sec += (int)(sp->ttis[otheri].tt_gmtoff -
2121 					sp->ttis[samei].tt_gmtoff);
2122 			tmp->tm_isdst = !tmp->tm_isdst;
2123 			t = time2(sp, tmp, funcp, offset, &okay);
2124 			if (okay)
2125 				return t;
2126 			tmp->tm_sec -= (int)(sp->ttis[otheri].tt_gmtoff -
2127 					sp->ttis[samei].tt_gmtoff);
2128 			tmp->tm_isdst = !tmp->tm_isdst;
2129 		}
2130 	}
2131 	errno = EOVERFLOW;
2132 	return WRONG;
2133 }
2134 
2135 time_t
2136 mktime_z(const timezone_t sp, struct tm *const tmp)
2137 {
2138 	time_t t;
2139 	if (sp == NULL)
2140 		t = time1(NULL, tmp, gmtsub, 0);
2141 	else
2142 		t = time1(sp, tmp, localsub, 0);
2143 	return t;
2144 }
2145 
2146 time_t
2147 mktime(struct tm *const tmp)
2148 {
2149 	time_t result;
2150 
2151 	rwlock_wrlock(&lcl_lock);
2152 	tzset_unlocked();
2153 	result = mktime_z(lclptr, tmp);
2154 	rwlock_unlock(&lcl_lock);
2155 	return result;
2156 }
2157 
2158 #ifdef STD_INSPIRED
2159 
2160 time_t
2161 timelocal_z(const timezone_t sp, struct tm *const tmp)
2162 {
2163 	if (tmp != NULL)
2164 		tmp->tm_isdst = -1;	/* in case it wasn't initialized */
2165 	return mktime_z(sp, tmp);
2166 }
2167 
2168 time_t
2169 timelocal(struct tm *const tmp)
2170 {
2171 	if (tmp != NULL)
2172 		tmp->tm_isdst = -1;	/* in case it wasn't initialized */
2173 	return mktime(tmp);
2174 }
2175 
2176 time_t
2177 timegm(struct tm *const tmp)
2178 {
2179 	time_t t;
2180 
2181 	if (tmp != NULL)
2182 		tmp->tm_isdst = 0;
2183 	t = time1(gmtptr, tmp, gmtsub, 0);
2184 	return t;
2185 }
2186 
2187 time_t
2188 timeoff(struct tm *const tmp, long offset)
2189 {
2190 	time_t t;
2191 
2192 	if ((offset > 0 && offset > INT_FAST32_MAX) ||
2193 	    (offset < 0 && offset < INT_FAST32_MIN)) {
2194 		errno = EOVERFLOW;
2195 		return -1;
2196 	}
2197 	if (tmp != NULL)
2198 		tmp->tm_isdst = 0;
2199 	t = time1(gmtptr, tmp, gmtsub, (int_fast32_t)offset);
2200 	return t;
2201 }
2202 
2203 #endif /* defined STD_INSPIRED */
2204 
2205 #ifdef CMUCS
2206 
2207 /*
2208 ** The following is supplied for compatibility with
2209 ** previous versions of the CMUCS runtime library.
2210 */
2211 
2212 long
2213 gtime(struct tm *const tmp)
2214 {
2215 	const time_t t = mktime(tmp);
2216 
2217 	if (t == WRONG)
2218 		return -1;
2219 	return t;
2220 }
2221 
2222 #endif /* defined CMUCS */
2223 
2224 /*
2225 ** XXX--is the below the right way to conditionalize??
2226 */
2227 
2228 #ifdef STD_INSPIRED
2229 
2230 /*
2231 ** IEEE Std 1003.1-1988 (POSIX) legislates that 536457599
2232 ** shall correspond to "Wed Dec 31 23:59:59 UTC 1986", which
2233 ** is not the case if we are accounting for leap seconds.
2234 ** So, we provide the following conversion routines for use
2235 ** when exchanging timestamps with POSIX conforming systems.
2236 */
2237 
2238 static int_fast64_t
2239 leapcorr(const timezone_t sp, time_t *timep)
2240 {
2241 	struct lsinfo * lp;
2242 	int		i;
2243 
2244 	i = sp->leapcnt;
2245 	while (--i >= 0) {
2246 		lp = &sp->lsis[i];
2247 		if (*timep >= lp->ls_trans)
2248 			return lp->ls_corr;
2249 	}
2250 	return 0;
2251 }
2252 
2253 time_t
2254 time2posix_z(const timezone_t sp, time_t t)
2255 {
2256 	return (time_t)(t - leapcorr(sp, &t));
2257 }
2258 
2259 time_t
2260 time2posix(time_t t)
2261 {
2262 	time_t result;
2263 	rwlock_wrlock(&lcl_lock);
2264 	tzset_unlocked();
2265 	result = (time_t)(t - leapcorr(lclptr, &t));
2266 	rwlock_unlock(&lcl_lock);
2267 	return (result);
2268 }
2269 
2270 time_t
2271 posix2time_z(const timezone_t sp, time_t t)
2272 {
2273 	time_t	x;
2274 	time_t	y;
2275 
2276 	/*
2277 	** For a positive leap second hit, the result
2278 	** is not unique. For a negative leap second
2279 	** hit, the corresponding time doesn't exist,
2280 	** so we return an adjacent second.
2281 	*/
2282 	x = (time_t)(t + leapcorr(sp, &t));
2283 	y = (time_t)(x - leapcorr(sp, &x));
2284 	if (y < t) {
2285 		do {
2286 			x++;
2287 			y = (time_t)(x - leapcorr(sp, &x));
2288 		} while (y < t);
2289 		if (t != y) {
2290 			return x - 1;
2291 		}
2292 	} else if (y > t) {
2293 		do {
2294 			--x;
2295 			y = (time_t)(x - leapcorr(sp, &x));
2296 		} while (y > t);
2297 		if (t != y) {
2298 			return x + 1;
2299 		}
2300 	}
2301 	return x;
2302 }
2303 
2304 
2305 
2306 time_t
2307 posix2time(time_t t)
2308 {
2309 	time_t result;
2310 
2311 	rwlock_wrlock(&lcl_lock);
2312 	tzset_unlocked();
2313 	result = posix2time_z(lclptr, t);
2314 	rwlock_unlock(&lcl_lock);
2315 	return result;
2316 }
2317 
2318 #endif /* defined STD_INSPIRED */
2319