xref: /netbsd-src/lib/libc/time/localtime.c (revision b7b7574d3bf8eeb51a1fa3977b59142ec6434a55)
1 /*	$NetBSD: localtime.c,v 1.82 2014/05/13 16:33:56 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 1.82 2014/05/13 16:33:56 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)
65 #endif /* defined O_BINARY */
66 #ifndef O_BINARY
67 #define OPEN_MODE	O_RDONLY
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 	u_t *			up;
390 
391 	up = malloc(sizeof *up);
392 	if (up == NULL)
393 		return -1;
394 
395 	sp->goback = sp->goahead = FALSE;
396 	if (name == NULL && (name = TZDEFAULT) == NULL)
397 		goto oops;
398 	{
399 		int	doaccess;
400 		/*
401 		** Section 4.9.1 of the C standard says that
402 		** "FILENAME_MAX expands to an integral constant expression
403 		** that is the size needed for an array of char large enough
404 		** to hold the longest file name string that the implementation
405 		** guarantees can be opened."
406 		*/
407 		char		fullname[FILENAME_MAX + 1];
408 
409 		if (name[0] == ':')
410 			++name;
411 		doaccess = name[0] == '/';
412 		if (!doaccess) {
413 			if ((p = TZDIR) == NULL)
414 				goto oops;
415 			if ((strlen(p) + strlen(name) + 1) >= sizeof fullname)
416 				goto oops;
417 			(void) strcpy(fullname, p);	/* XXX strcpy is safe */
418 			(void) strcat(fullname, "/");	/* XXX strcat is safe */
419 			(void) strcat(fullname, name);	/* XXX strcat is safe */
420 			/*
421 			** Set doaccess if '.' (as in "../") shows up in name.
422 			*/
423 			if (strchr(name, '.') != NULL)
424 				doaccess = TRUE;
425 			name = fullname;
426 		}
427 		if (doaccess && access(name, R_OK) != 0)
428 			goto oops;
429 		/*
430 		 * XXX potential security problem here if user of a set-id
431 		 * program has set TZ (which is passed in as name) here,
432 		 * and uses a race condition trick to defeat the access(2)
433 		 * above.
434 		 */
435 		if ((fid = open(name, OPEN_MODE)) == -1)
436 			goto oops;
437 	}
438 	nread = read(fid, up->buf, sizeof up->buf);
439 	if (close(fid) < 0 || nread <= 0)
440 		goto oops;
441 	for (stored = 4; stored <= 8; stored *= 2) {
442 		int		ttisstdcnt;
443 		int		ttisgmtcnt;
444 		int		timecnt;
445 
446 		ttisstdcnt = (int) detzcode(up->tzhead.tzh_ttisstdcnt);
447 		ttisgmtcnt = (int) detzcode(up->tzhead.tzh_ttisgmtcnt);
448 		sp->leapcnt = (int) detzcode(up->tzhead.tzh_leapcnt);
449 		sp->timecnt = (int) detzcode(up->tzhead.tzh_timecnt);
450 		sp->typecnt = (int) detzcode(up->tzhead.tzh_typecnt);
451 		sp->charcnt = (int) detzcode(up->tzhead.tzh_charcnt);
452 		p = up->tzhead.tzh_charcnt + sizeof up->tzhead.tzh_charcnt;
453 		if (sp->leapcnt < 0 || sp->leapcnt > TZ_MAX_LEAPS ||
454 			sp->typecnt <= 0 || sp->typecnt > TZ_MAX_TYPES ||
455 			sp->timecnt < 0 || sp->timecnt > TZ_MAX_TIMES ||
456 			sp->charcnt < 0 || sp->charcnt > TZ_MAX_CHARS ||
457 			(ttisstdcnt != sp->typecnt && ttisstdcnt != 0) ||
458 			(ttisgmtcnt != sp->typecnt && ttisgmtcnt != 0))
459 				goto oops;
460 		if (nread - (p - up->buf) <
461 			sp->timecnt * stored +		/* ats */
462 			sp->timecnt +			/* types */
463 			sp->typecnt * 6 +		/* ttinfos */
464 			sp->charcnt +			/* chars */
465 			sp->leapcnt * (stored + 4) +	/* lsinfos */
466 			ttisstdcnt +			/* ttisstds */
467 			ttisgmtcnt)			/* ttisgmts */
468 				goto oops;
469 		timecnt = 0;
470 		for (i = 0; i < sp->timecnt; ++i) {
471 			int_fast64_t at
472 			  = stored == 4 ? detzcode(p) : detzcode64(p);
473 			sp->types[i] = ((TYPE_SIGNED(time_t)
474 					 ? time_t_min <= at
475 					 : 0 <= at)
476 					&& at <= time_t_max);
477 			if (sp->types[i]) {
478 				if (i && !timecnt && at != time_t_min) {
479 					/*
480 					** Keep the earlier record, but tweak
481 					** it so that it starts with the
482 					** minimum time_t value.
483 					*/
484 					sp->types[i - 1] = 1;
485 					sp->ats[timecnt++] = time_t_min;
486 				}
487 				_DIAGASSERT(__type_fit(time_t, at));
488 				sp->ats[timecnt++] = (time_t)at;
489 			}
490 			p += stored;
491 		}
492 		timecnt = 0;
493 		for (i = 0; i < sp->timecnt; ++i) {
494 			unsigned char typ = *p++;
495 			if (sp->typecnt <= typ)
496 				goto oops;
497 			if (sp->types[i])
498 				sp->types[timecnt++] = typ;
499 		}
500 		for (i = 0; i < sp->typecnt; ++i) {
501 			struct ttinfo *	ttisp;
502 
503 			ttisp = &sp->ttis[i];
504 			ttisp->tt_gmtoff = detzcode(p);
505 			p += 4;
506 			ttisp->tt_isdst = (unsigned char) *p++;
507 			if (ttisp->tt_isdst != 0 && ttisp->tt_isdst != 1)
508 				goto oops;
509 			ttisp->tt_abbrind = (unsigned char) *p++;
510 			if (ttisp->tt_abbrind < 0 ||
511 				ttisp->tt_abbrind > sp->charcnt)
512 					goto oops;
513 		}
514 		for (i = 0; i < sp->charcnt; ++i)
515 			sp->chars[i] = *p++;
516 		sp->chars[i] = '\0';	/* ensure '\0' at end */
517 		for (i = 0; i < sp->leapcnt; ++i) {
518 			struct lsinfo *	lsisp;
519 
520 			lsisp = &sp->lsis[i];
521 			lsisp->ls_trans = (time_t)((stored == 4) ?
522 			    detzcode(p) : detzcode64(p));
523 			p += stored;
524 			lsisp->ls_corr = detzcode(p);
525 			p += 4;
526 		}
527 		for (i = 0; i < sp->typecnt; ++i) {
528 			struct ttinfo *	ttisp;
529 
530 			ttisp = &sp->ttis[i];
531 			if (ttisstdcnt == 0)
532 				ttisp->tt_ttisstd = FALSE;
533 			else {
534 				ttisp->tt_ttisstd = *p++;
535 				if (ttisp->tt_ttisstd != TRUE &&
536 					ttisp->tt_ttisstd != FALSE)
537 						goto oops;
538 			}
539 		}
540 		for (i = 0; i < sp->typecnt; ++i) {
541 			struct ttinfo *	ttisp;
542 
543 			ttisp = &sp->ttis[i];
544 			if (ttisgmtcnt == 0)
545 				ttisp->tt_ttisgmt = FALSE;
546 			else {
547 				ttisp->tt_ttisgmt = *p++;
548 				if (ttisp->tt_ttisgmt != TRUE &&
549 					ttisp->tt_ttisgmt != FALSE)
550 						goto oops;
551 			}
552 		}
553 		/*
554 		** If this is an old file, we're done.
555 		*/
556 		if (up->tzhead.tzh_version[0] == '\0')
557 			break;
558 		nread -= p - up->buf;
559 		for (i = 0; i < nread; ++i)
560 			up->buf[i] = p[i];
561 		/*
562 		** If this is a signed narrow time_t system, we're done.
563 		*/
564 		if (TYPE_SIGNED(time_t) && stored >= (int) sizeof(time_t))
565 			break;
566 	}
567 	if (doextend && nread > 2 &&
568 		up->buf[0] == '\n' && up->buf[nread - 1] == '\n' &&
569 		sp->typecnt + 2 <= TZ_MAX_TYPES) {
570 			struct __state ts;
571 			int	result;
572 
573 			up->buf[nread - 1] = '\0';
574 			result = tzparse(&ts, &up->buf[1], FALSE);
575 			if (result == 0 && ts.typecnt == 2 &&
576 				sp->charcnt + ts.charcnt <= TZ_MAX_CHARS) {
577 					for (i = 0; i < 2; ++i)
578 						ts.ttis[i].tt_abbrind +=
579 							sp->charcnt;
580 					for (i = 0; i < ts.charcnt; ++i)
581 						sp->chars[sp->charcnt++] =
582 							ts.chars[i];
583 					i = 0;
584 					while (i < ts.timecnt &&
585 						ts.ats[i] <=
586 						sp->ats[sp->timecnt - 1])
587 							++i;
588 					while (i < ts.timecnt &&
589 					    sp->timecnt < TZ_MAX_TIMES) {
590 						sp->ats[sp->timecnt] =
591 							ts.ats[i];
592 						sp->types[sp->timecnt] =
593 							sp->typecnt +
594 							ts.types[i];
595 						++sp->timecnt;
596 						++i;
597 					}
598 					sp->ttis[sp->typecnt++] = ts.ttis[0];
599 					sp->ttis[sp->typecnt++] = ts.ttis[1];
600 			}
601 	}
602 	if (sp->timecnt > 1) {
603 		for (i = 1; i < sp->timecnt; ++i)
604 			if (typesequiv(sp, sp->types[i], sp->types[0]) &&
605 				differ_by_repeat(sp->ats[i], sp->ats[0])) {
606 					sp->goback = TRUE;
607 					break;
608 				}
609 		for (i = sp->timecnt - 2; i >= 0; --i)
610 			if (typesequiv(sp, sp->types[sp->timecnt - 1],
611 				sp->types[i]) &&
612 				differ_by_repeat(sp->ats[sp->timecnt - 1],
613 				sp->ats[i])) {
614 					sp->goahead = TRUE;
615 					break;
616 		}
617 	}
618 	/*
619 	** If type 0 is is unused in transitions,
620 	** it's the type to use for early times.
621 	*/
622 	for (i = 0; i < sp->typecnt; ++i)
623 		if (sp->types[i] == 0)
624 			break;
625 	i = (i >= sp->typecnt) ? 0 : -1;
626 	/*
627 	** Absent the above,
628 	** if there are transition times
629 	** and the first transition is to a daylight time
630 	** find the standard type less than and closest to
631 	** the type of the first transition.
632 	*/
633 	if (i < 0 && sp->timecnt > 0 && sp->ttis[sp->types[0]].tt_isdst) {
634 		i = sp->types[0];
635 		while (--i >= 0)
636 			if (!sp->ttis[i].tt_isdst)
637 				break;
638 	}
639 	/*
640 	** If no result yet, find the first standard type.
641 	** If there is none, punt to type zero.
642 	*/
643 	if (i < 0) {
644 		i = 0;
645 		while (sp->ttis[i].tt_isdst)
646 			if (++i >= sp->typecnt) {
647 				i = 0;
648 				break;
649 			}
650 	}
651 	sp->defaulttype = i;
652 	free(up);
653 	return 0;
654 oops:
655 	free(up);
656 	return -1;
657 }
658 
659 static int
660 typesequiv(const timezone_t sp, const int a, const int b)
661 {
662 	int	result;
663 
664 	if (sp == NULL ||
665 		a < 0 || a >= sp->typecnt ||
666 		b < 0 || b >= sp->typecnt)
667 			result = FALSE;
668 	else {
669 		const struct ttinfo *	ap = &sp->ttis[a];
670 		const struct ttinfo *	bp = &sp->ttis[b];
671 		result = ap->tt_gmtoff == bp->tt_gmtoff &&
672 			ap->tt_isdst == bp->tt_isdst &&
673 			ap->tt_ttisstd == bp->tt_ttisstd &&
674 			ap->tt_ttisgmt == bp->tt_ttisgmt &&
675 			strcmp(&sp->chars[ap->tt_abbrind],
676 			&sp->chars[bp->tt_abbrind]) == 0;
677 	}
678 	return result;
679 }
680 
681 static const int	mon_lengths[2][MONSPERYEAR] = {
682 	{ 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 },
683 	{ 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }
684 };
685 
686 static const int	year_lengths[2] = {
687 	DAYSPERNYEAR, DAYSPERLYEAR
688 };
689 
690 /*
691 ** Given a pointer into a time zone string, scan until a character that is not
692 ** a valid character in a zone name is found. Return a pointer to that
693 ** character.
694 */
695 
696 static const char *
697 getzname(const char *strp)
698 {
699 	char	c;
700 
701 	while ((c = *strp) != '\0' && !is_digit(c) && c != ',' && c != '-' &&
702 		c != '+')
703 			++strp;
704 	return strp;
705 }
706 
707 /*
708 ** Given a pointer into an extended time zone string, scan until the ending
709 ** delimiter of the zone name is located. Return a pointer to the delimiter.
710 **
711 ** As with getzname above, the legal character set is actually quite
712 ** restricted, with other characters producing undefined results.
713 ** We don't do any checking here; checking is done later in common-case code.
714 */
715 
716 static const char *
717 getqzname(const char *strp, const int delim)
718 {
719 	int	c;
720 
721 	while ((c = *strp) != '\0' && c != delim)
722 		++strp;
723 	return strp;
724 }
725 
726 /*
727 ** Given a pointer into a time zone string, extract a number from that string.
728 ** Check that the number is within a specified range; if it is not, return
729 ** NULL.
730 ** Otherwise, return a pointer to the first character not part of the number.
731 */
732 
733 static const char *
734 getnum(const char *strp, int *const nump, const int min, const int max)
735 {
736 	char	c;
737 	int	num;
738 
739 	if (strp == NULL || !is_digit(c = *strp)) {
740 		errno = EINVAL;
741 		return NULL;
742 	}
743 	num = 0;
744 	do {
745 		num = num * 10 + (c - '0');
746 		if (num > max) {
747 			errno = EOVERFLOW;
748 			return NULL;	/* illegal value */
749 		}
750 		c = *++strp;
751 	} while (is_digit(c));
752 	if (num < min) {
753 		errno = EINVAL;
754 		return NULL;		/* illegal value */
755 	}
756 	*nump = num;
757 	return strp;
758 }
759 
760 /*
761 ** Given a pointer into a time zone string, extract a number of seconds,
762 ** in hh[:mm[:ss]] form, from the string.
763 ** If any error occurs, return NULL.
764 ** Otherwise, return a pointer to the first character not part of the number
765 ** of seconds.
766 */
767 
768 static const char *
769 getsecs(const char *strp, int_fast32_t *const secsp)
770 {
771 	int	num;
772 
773 	/*
774 	** `HOURSPERDAY * DAYSPERWEEK - 1' allows quasi-Posix rules like
775 	** "M10.4.6/26", which does not conform to Posix,
776 	** but which specifies the equivalent of
777 	** ``02:00 on the first Sunday on or after 23 Oct''.
778 	*/
779 	strp = getnum(strp, &num, 0, HOURSPERDAY * DAYSPERWEEK - 1);
780 	if (strp == NULL)
781 		return NULL;
782 	*secsp = num * (int_fast32_t) SECSPERHOUR;
783 	if (*strp == ':') {
784 		++strp;
785 		strp = getnum(strp, &num, 0, MINSPERHOUR - 1);
786 		if (strp == NULL)
787 			return NULL;
788 		*secsp += num * SECSPERMIN;
789 		if (*strp == ':') {
790 			++strp;
791 			/* `SECSPERMIN' allows for leap seconds. */
792 			strp = getnum(strp, &num, 0, SECSPERMIN);
793 			if (strp == NULL)
794 				return NULL;
795 			*secsp += num;
796 		}
797 	}
798 	return strp;
799 }
800 
801 /*
802 ** Given a pointer into a time zone string, extract an offset, in
803 ** [+-]hh[:mm[:ss]] form, from the string.
804 ** If any error occurs, return NULL.
805 ** Otherwise, return a pointer to the first character not part of the time.
806 */
807 
808 static const char *
809 getoffset(const char *strp, int_fast32_t *const offsetp)
810 {
811 	int	neg = 0;
812 
813 	if (*strp == '-') {
814 		neg = 1;
815 		++strp;
816 	} else if (*strp == '+')
817 		++strp;
818 	strp = getsecs(strp, offsetp);
819 	if (strp == NULL)
820 		return NULL;		/* illegal time */
821 	if (neg)
822 		*offsetp = -*offsetp;
823 	return strp;
824 }
825 
826 /*
827 ** Given a pointer into a time zone string, extract a rule in the form
828 ** date[/time]. See POSIX section 8 for the format of "date" and "time".
829 ** If a valid rule is not found, return NULL.
830 ** Otherwise, return a pointer to the first character not part of the rule.
831 */
832 
833 static const char *
834 getrule(const char *strp, struct rule *const rulep)
835 {
836 	if (*strp == 'J') {
837 		/*
838 		** Julian day.
839 		*/
840 		rulep->r_type = JULIAN_DAY;
841 		++strp;
842 		strp = getnum(strp, &rulep->r_day, 1, DAYSPERNYEAR);
843 	} else if (*strp == 'M') {
844 		/*
845 		** Month, week, day.
846 		*/
847 		rulep->r_type = MONTH_NTH_DAY_OF_WEEK;
848 		++strp;
849 		strp = getnum(strp, &rulep->r_mon, 1, MONSPERYEAR);
850 		if (strp == NULL)
851 			return NULL;
852 		if (*strp++ != '.')
853 			return NULL;
854 		strp = getnum(strp, &rulep->r_week, 1, 5);
855 		if (strp == NULL)
856 			return NULL;
857 		if (*strp++ != '.')
858 			return NULL;
859 		strp = getnum(strp, &rulep->r_day, 0, DAYSPERWEEK - 1);
860 	} else if (is_digit(*strp)) {
861 		/*
862 		** Day of year.
863 		*/
864 		rulep->r_type = DAY_OF_YEAR;
865 		strp = getnum(strp, &rulep->r_day, 0, DAYSPERLYEAR - 1);
866 	} else	return NULL;		/* invalid format */
867 	if (strp == NULL)
868 		return NULL;
869 	if (*strp == '/') {
870 		/*
871 		** Time specified.
872 		*/
873 		++strp;
874 		strp = getoffset(strp, &rulep->r_time);
875 	} else	rulep->r_time = 2 * SECSPERHOUR;	/* default = 2:00:00 */
876 	return strp;
877 }
878 
879 /*
880 ** Given a year, a rule, and the offset from UT at the time that rule takes
881 ** effect, calculate the year-relative time that rule takes effect.
882 */
883 
884 static int_fast32_t
885 transtime(const int year, const struct rule *const rulep,
886 	  const int_fast32_t offset)
887 {
888 	int	leapyear;
889 	int_fast32_t	value;
890 	int	i;
891 	int		d, m1, yy0, yy1, yy2, dow;
892 
893 	INITIALIZE(value);
894 	leapyear = isleap(year);
895 	switch (rulep->r_type) {
896 
897 	case JULIAN_DAY:
898 		/*
899 		** Jn - Julian day, 1 == January 1, 60 == March 1 even in leap
900 		** years.
901 		** In non-leap years, or if the day number is 59 or less, just
902 		** add SECSPERDAY times the day number-1 to the time of
903 		** January 1, midnight, to get the day.
904 		*/
905 		value = (rulep->r_day - 1) * SECSPERDAY;
906 		if (leapyear && rulep->r_day >= 60)
907 			value += SECSPERDAY;
908 		break;
909 
910 	case DAY_OF_YEAR:
911 		/*
912 		** n - day of year.
913 		** Just add SECSPERDAY times the day number to the time of
914 		** January 1, midnight, to get the day.
915 		*/
916 		value = rulep->r_day * SECSPERDAY;
917 		break;
918 
919 	case MONTH_NTH_DAY_OF_WEEK:
920 		/*
921 		** Mm.n.d - nth "dth day" of month m.
922 		*/
923 
924 		/*
925 		** Use Zeller's Congruence to get day-of-week of first day of
926 		** month.
927 		*/
928 		m1 = (rulep->r_mon + 9) % 12 + 1;
929 		yy0 = (rulep->r_mon <= 2) ? (year - 1) : year;
930 		yy1 = yy0 / 100;
931 		yy2 = yy0 % 100;
932 		dow = ((26 * m1 - 2) / 10 +
933 			1 + yy2 + yy2 / 4 + yy1 / 4 - 2 * yy1) % 7;
934 		if (dow < 0)
935 			dow += DAYSPERWEEK;
936 
937 		/*
938 		** "dow" is the day-of-week of the first day of the month. Get
939 		** the day-of-month (zero-origin) of the first "dow" day of the
940 		** month.
941 		*/
942 		d = rulep->r_day - dow;
943 		if (d < 0)
944 			d += DAYSPERWEEK;
945 		for (i = 1; i < rulep->r_week; ++i) {
946 			if (d + DAYSPERWEEK >=
947 				mon_lengths[leapyear][rulep->r_mon - 1])
948 					break;
949 			d += DAYSPERWEEK;
950 		}
951 
952 		/*
953 		** "d" is the day-of-month (zero-origin) of the day we want.
954 		*/
955 		value = d * SECSPERDAY;
956 		for (i = 0; i < rulep->r_mon - 1; ++i)
957 			value += mon_lengths[leapyear][i] * SECSPERDAY;
958 		break;
959 	}
960 
961 	/*
962 	** "value" is the year-relative time of 00:00:00 UT on the day in
963 	** question. To get the year-relative time of the specified local
964 	** time on that day, add the transition time and the current offset
965 	** from UT.
966 	*/
967 	return value + rulep->r_time + offset;
968 }
969 
970 /*
971 ** Given a POSIX section 8-style TZ string, fill in the rule tables as
972 ** appropriate.
973 */
974 
975 static int
976 tzparse(timezone_t sp, const char *name, const int lastditch)
977 {
978 	const char *		stdname;
979 	const char *		dstname;
980 	size_t			stdlen;
981 	size_t			dstlen;
982 	int_fast32_t		stdoffset;
983 	int_fast32_t		dstoffset;
984 	char *			cp;
985 	int			load_result;
986 
987 	INITIALIZE(dstname);
988 	stdname = name;
989 	if (lastditch) {
990 		stdlen = strlen(name);	/* length of standard zone name */
991 		name += stdlen;
992 		if (stdlen >= sizeof sp->chars)
993 			stdlen = (sizeof sp->chars) - 1;
994 		stdoffset = 0;
995 	} else {
996 		if (*name == '<') {
997 			name++;
998 			stdname = name;
999 			name = getqzname(name, '>');
1000 			if (*name != '>')
1001 				return (-1);
1002 			stdlen = name - stdname;
1003 			name++;
1004 		} else {
1005 			name = getzname(name);
1006 			stdlen = name - stdname;
1007 		}
1008 		if (*name == '\0')
1009 			return -1;
1010 		name = getoffset(name, &stdoffset);
1011 		if (name == NULL)
1012 			return -1;
1013 	}
1014 	load_result = tzload(sp, TZDEFRULES, FALSE);
1015 	if (load_result != 0)
1016 		sp->leapcnt = 0;		/* so, we're off a little */
1017 	if (*name != '\0') {
1018 		if (*name == '<') {
1019 			dstname = ++name;
1020 			name = getqzname(name, '>');
1021 			if (*name != '>')
1022 				return -1;
1023 			dstlen = name - dstname;
1024 			name++;
1025 		} else {
1026 			dstname = name;
1027 			name = getzname(name);
1028 			dstlen = name - dstname; /* length of DST zone name */
1029 		}
1030 		if (*name != '\0' && *name != ',' && *name != ';') {
1031 			name = getoffset(name, &dstoffset);
1032 			if (name == NULL)
1033 				return -1;
1034 		} else	dstoffset = stdoffset - SECSPERHOUR;
1035 		if (*name == '\0' && load_result != 0)
1036 			name = TZDEFRULESTRING;
1037 		if (*name == ',' || *name == ';') {
1038 			struct rule	start;
1039 			struct rule	end;
1040 			int		year;
1041 			int		yearlim;
1042 			int		timecnt;
1043 			time_t		janfirst;
1044 
1045 			++name;
1046 			if ((name = getrule(name, &start)) == NULL)
1047 				return -1;
1048 			if (*name++ != ',')
1049 				return -1;
1050 			if ((name = getrule(name, &end)) == NULL)
1051 				return -1;
1052 			if (*name != '\0')
1053 				return -1;
1054 			sp->typecnt = 2;	/* standard time and DST */
1055 			/*
1056 			** Two transitions per year, from EPOCH_YEAR forward.
1057 			*/
1058 			memset(sp->ttis, 0, sizeof(sp->ttis));
1059 			sp->ttis[0].tt_gmtoff = -dstoffset;
1060 			sp->ttis[0].tt_isdst = 1;
1061 			sp->ttis[0].tt_abbrind = (int)(stdlen + 1);
1062 			sp->ttis[1].tt_gmtoff = -stdoffset;
1063 			sp->ttis[1].tt_isdst = 0;
1064 			sp->ttis[1].tt_abbrind = 0;
1065 			sp->defaulttype = 0;
1066 			timecnt = 0;
1067 			janfirst = 0;
1068 			sp->timecnt = 0;
1069 			yearlim = EPOCH_YEAR + YEARSPERREPEAT;
1070 			for (year = EPOCH_YEAR; year < yearlim; year++) {
1071 				int_fast32_t
1072 				  starttime = transtime(year, &start, stdoffset),
1073 				  endtime = transtime(year, &end, dstoffset);
1074 				int_fast32_t
1075 				  yearsecs = (year_lengths[isleap(year)]
1076 					      * SECSPERDAY);
1077 				int reversed = endtime < starttime;
1078 				if (reversed) {
1079 					int_fast32_t swap = starttime;
1080 					starttime = endtime;
1081 					endtime = swap;
1082 				}
1083 				if (reversed
1084 				    || (starttime < endtime
1085 					&& (endtime - starttime
1086 					    < (yearsecs
1087 					       + (stdoffset - dstoffset))))) {
1088 					if (TZ_MAX_TIMES - 2 < timecnt)
1089 						break;
1090 					yearlim = year + YEARSPERREPEAT + 1;
1091 					sp->ats[timecnt] = janfirst;
1092 					if (increment_overflow_time
1093 					    (&sp->ats[timecnt], starttime))
1094 						break;
1095 					sp->types[timecnt++] = reversed;
1096 					sp->ats[timecnt] = janfirst;
1097 					if (increment_overflow_time
1098 					    (&sp->ats[timecnt], endtime))
1099 						break;
1100 					sp->types[timecnt++] = !reversed;
1101 				}
1102 				if (increment_overflow_time(&janfirst, yearsecs))
1103 					break;
1104 			}
1105 			sp->timecnt = timecnt;
1106 			if (!timecnt)
1107 				sp->typecnt = 1;	/* Perpetual DST.  */
1108 		} else {
1109 			int_fast32_t	theirstdoffset;
1110 			int_fast32_t	theirdstoffset;
1111 			int_fast32_t	theiroffset;
1112 			int		isdst;
1113 			int		i;
1114 			int		j;
1115 
1116 			if (*name != '\0')
1117 				return -1;
1118 			/*
1119 			** Initial values of theirstdoffset and theirdstoffset.
1120 			*/
1121 			theirstdoffset = 0;
1122 			for (i = 0; i < sp->timecnt; ++i) {
1123 				j = sp->types[i];
1124 				if (!sp->ttis[j].tt_isdst) {
1125 					theirstdoffset =
1126 						-sp->ttis[j].tt_gmtoff;
1127 					break;
1128 				}
1129 			}
1130 			theirdstoffset = 0;
1131 			for (i = 0; i < sp->timecnt; ++i) {
1132 				j = sp->types[i];
1133 				if (sp->ttis[j].tt_isdst) {
1134 					theirdstoffset =
1135 						-sp->ttis[j].tt_gmtoff;
1136 					break;
1137 				}
1138 			}
1139 			/*
1140 			** Initially we're assumed to be in standard time.
1141 			*/
1142 			isdst = FALSE;
1143 			theiroffset = theirstdoffset;
1144 			/*
1145 			** Now juggle transition times and types
1146 			** tracking offsets as you do.
1147 			*/
1148 			for (i = 0; i < sp->timecnt; ++i) {
1149 				j = sp->types[i];
1150 				sp->types[i] = sp->ttis[j].tt_isdst;
1151 				if (sp->ttis[j].tt_ttisgmt) {
1152 					/* No adjustment to transition time */
1153 				} else {
1154 					/*
1155 					** If summer time is in effect, and the
1156 					** transition time was not specified as
1157 					** standard time, add the summer time
1158 					** offset to the transition time;
1159 					** otherwise, add the standard time
1160 					** offset to the transition time.
1161 					*/
1162 					/*
1163 					** Transitions from DST to DDST
1164 					** will effectively disappear since
1165 					** POSIX provides for only one DST
1166 					** offset.
1167 					*/
1168 					if (isdst && !sp->ttis[j].tt_ttisstd) {
1169 						sp->ats[i] += (time_t)
1170 						    (dstoffset - theirdstoffset);
1171 					} else {
1172 						sp->ats[i] += (time_t)
1173 						    (stdoffset - theirstdoffset);
1174 					}
1175 				}
1176 				theiroffset = -sp->ttis[j].tt_gmtoff;
1177 				if (!sp->ttis[j].tt_isdst)
1178 					theirstdoffset = theiroffset;
1179 				else	theirdstoffset = theiroffset;
1180 			}
1181 			/*
1182 			** Finally, fill in ttis.
1183 			** ttisstd and ttisgmt need not be handled
1184 			*/
1185 			memset(sp->ttis, 0, sizeof(sp->ttis));
1186 			sp->ttis[0].tt_gmtoff = -stdoffset;
1187 			sp->ttis[0].tt_isdst = FALSE;
1188 			sp->ttis[0].tt_abbrind = 0;
1189 			sp->ttis[1].tt_gmtoff = -dstoffset;
1190 			sp->ttis[1].tt_isdst = TRUE;
1191 			sp->ttis[1].tt_abbrind = (int)(stdlen + 1);
1192 			sp->typecnt = 2;
1193 			sp->defaulttype = 0;
1194 		}
1195 	} else {
1196 		dstlen = 0;
1197 		sp->typecnt = 1;		/* only standard time */
1198 		sp->timecnt = 0;
1199 		memset(sp->ttis, 0, sizeof(sp->ttis));
1200 		sp->ttis[0].tt_gmtoff = -stdoffset;
1201 		sp->ttis[0].tt_isdst = 0;
1202 		sp->ttis[0].tt_abbrind = 0;
1203 		sp->defaulttype = 0;
1204 	}
1205 	sp->charcnt = (int)(stdlen + 1);
1206 	if (dstlen != 0)
1207 		sp->charcnt += (int)(dstlen + 1);
1208 	if ((size_t) sp->charcnt > sizeof sp->chars)
1209 		return -1;
1210 	cp = sp->chars;
1211 	(void) strncpy(cp, stdname, stdlen);
1212 	cp += stdlen;
1213 	*cp++ = '\0';
1214 	if (dstlen != 0) {
1215 		(void) strncpy(cp, dstname, dstlen);
1216 		*(cp + dstlen) = '\0';
1217 	}
1218 	return 0;
1219 }
1220 
1221 static void
1222 gmtload(timezone_t sp)
1223 {
1224 	if (tzload(sp, gmt, TRUE) != 0)
1225 		(void) tzparse(sp, gmt, TRUE);
1226 }
1227 
1228 timezone_t
1229 tzalloc(const char *name)
1230 {
1231 	timezone_t sp = malloc(sizeof *sp);
1232 	if (sp == NULL)
1233 		return NULL;
1234 	if (tzload(sp, name, TRUE) != 0) {
1235 		free(sp);
1236 		return NULL;
1237 	}
1238 	settzname_z(sp);
1239 	return sp;
1240 }
1241 
1242 void
1243 tzfree(const timezone_t sp)
1244 {
1245 	free(sp);
1246 }
1247 
1248 static void
1249 tzsetwall_unlocked(void)
1250 {
1251 	if (lcl_is_set < 0)
1252 		return;
1253 	lcl_is_set = -1;
1254 
1255 	if (lclptr == NULL) {
1256 		int saveerrno = errno;
1257 		lclptr = malloc(sizeof *lclptr);
1258 		errno = saveerrno;
1259 		if (lclptr == NULL) {
1260 			settzname();	/* all we can do */
1261 			return;
1262 		}
1263 	}
1264 	if (tzload(lclptr, NULL, TRUE) != 0)
1265 		gmtload(lclptr);
1266 	settzname();
1267 }
1268 
1269 #ifndef STD_INSPIRED
1270 /*
1271 ** A non-static declaration of tzsetwall in a system header file
1272 ** may cause a warning about this upcoming static declaration...
1273 */
1274 static
1275 #endif /* !defined STD_INSPIRED */
1276 void
1277 tzsetwall(void)
1278 {
1279 	rwlock_wrlock(&lcl_lock);
1280 	tzsetwall_unlocked();
1281 	rwlock_unlock(&lcl_lock);
1282 }
1283 
1284 #ifndef STD_INSPIRED
1285 /*
1286 ** A non-static declaration of tzsetwall in a system header file
1287 ** may cause a warning about this upcoming static declaration...
1288 */
1289 static
1290 #endif /* !defined STD_INSPIRED */
1291 void
1292 tzset_unlocked(void)
1293 {
1294 	const char *	name;
1295 
1296 	name = getenv("TZ");
1297 	if (name == NULL) {
1298 		tzsetwall_unlocked();
1299 		return;
1300 	}
1301 
1302 	if (lcl_is_set > 0 && strcmp(lcl_TZname, name) == 0)
1303 		return;
1304 	lcl_is_set = strlen(name) < sizeof lcl_TZname;
1305 	if (lcl_is_set)
1306 		(void)strlcpy(lcl_TZname, name, sizeof(lcl_TZname));
1307 
1308 	if (lclptr == NULL) {
1309 		int saveerrno = errno;
1310 		lclptr = malloc(sizeof *lclptr);
1311 		errno = saveerrno;
1312 		if (lclptr == NULL) {
1313 			settzname();	/* all we can do */
1314 			return;
1315 		}
1316 	}
1317 	if (*name == '\0') {
1318 		/*
1319 		** User wants it fast rather than right.
1320 		*/
1321 		lclptr->leapcnt = 0;		/* so, we're off a little */
1322 		lclptr->timecnt = 0;
1323 		lclptr->typecnt = 0;
1324 		lclptr->ttis[0].tt_isdst = 0;
1325 		lclptr->ttis[0].tt_gmtoff = 0;
1326 		lclptr->ttis[0].tt_abbrind = 0;
1327 		(void) strlcpy(lclptr->chars, gmt, sizeof(lclptr->chars));
1328 	} else if (tzload(lclptr, name, TRUE) != 0)
1329 		if (name[0] == ':' || tzparse(lclptr, name, FALSE) != 0)
1330 			(void) gmtload(lclptr);
1331 	settzname();
1332 }
1333 
1334 void
1335 tzset(void)
1336 {
1337 	rwlock_wrlock(&lcl_lock);
1338 	tzset_unlocked();
1339 	rwlock_unlock(&lcl_lock);
1340 }
1341 
1342 /*
1343 ** The easy way to behave "as if no library function calls" localtime
1344 ** is to not call it--so we drop its guts into "localsub", which can be
1345 ** freely called. (And no, the PANS doesn't require the above behavior--
1346 ** but it *is* desirable.)
1347 **
1348 ** The unused offset argument is for the benefit of mktime variants.
1349 */
1350 
1351 /*ARGSUSED*/
1352 static struct tm *
1353 localsub(const timezone_t sp, const time_t * const timep, const int_fast32_t offset,
1354     struct tm *const tmp)
1355 {
1356 	const struct ttinfo *	ttisp;
1357 	int			i;
1358 	struct tm *		result;
1359 	const time_t			t = *timep;
1360 
1361 	if ((sp->goback && t < sp->ats[0]) ||
1362 		(sp->goahead && t > sp->ats[sp->timecnt - 1])) {
1363 			time_t			newt = t;
1364 			time_t		seconds;
1365 			time_t		years;
1366 
1367 			if (t < sp->ats[0])
1368 				seconds = sp->ats[0] - t;
1369 			else	seconds = t - sp->ats[sp->timecnt - 1];
1370 			--seconds;
1371 			years = (time_t)((seconds / SECSPERREPEAT + 1) * YEARSPERREPEAT);
1372 			seconds = (time_t)(years * AVGSECSPERYEAR);
1373 			if (t < sp->ats[0])
1374 				newt += seconds;
1375 			else	newt -= seconds;
1376 			if (newt < sp->ats[0] ||
1377 				newt > sp->ats[sp->timecnt - 1])
1378 					return NULL;	/* "cannot happen" */
1379 			result = localsub(sp, &newt, offset, tmp);
1380 			if (result == tmp) {
1381 				time_t	newy;
1382 
1383 				newy = tmp->tm_year;
1384 				if (t < sp->ats[0])
1385 					newy -= years;
1386 				else	newy += years;
1387 				tmp->tm_year = (int)newy;
1388 				if (tmp->tm_year != newy)
1389 					return NULL;
1390 			}
1391 			return result;
1392 	}
1393 	if (sp->timecnt == 0 || t < sp->ats[0]) {
1394 		i = sp->defaulttype;
1395 	} else {
1396 		int	lo = 1;
1397 		int	hi = sp->timecnt;
1398 
1399 		while (lo < hi) {
1400 			int	mid = (lo + hi) / 2;
1401 
1402 			if (t < sp->ats[mid])
1403 				hi = mid;
1404 			else	lo = mid + 1;
1405 		}
1406 		i = (int) sp->types[lo - 1];
1407 	}
1408 	ttisp = &sp->ttis[i];
1409 	/*
1410 	** To get (wrong) behavior that's compatible with System V Release 2.0
1411 	** you'd replace the statement below with
1412 	**	t += ttisp->tt_gmtoff;
1413 	**	timesub(&t, 0L, sp, tmp);
1414 	*/
1415 	result = timesub(sp, &t, ttisp->tt_gmtoff, tmp);
1416 	tmp->tm_isdst = ttisp->tt_isdst;
1417 	if (sp == lclptr)
1418 		tzname[tmp->tm_isdst] = &sp->chars[ttisp->tt_abbrind];
1419 #ifdef TM_ZONE
1420 	tmp->TM_ZONE = &sp->chars[ttisp->tt_abbrind];
1421 #endif /* defined TM_ZONE */
1422 	return result;
1423 }
1424 
1425 /*
1426 ** Re-entrant version of localtime.
1427 */
1428 
1429 struct tm *
1430 localtime_r(const time_t * __restrict timep, struct tm *tmp)
1431 {
1432 	rwlock_rdlock(&lcl_lock);
1433 	tzset_unlocked();
1434 	tmp = localtime_rz(lclptr, timep, tmp);
1435 	rwlock_unlock(&lcl_lock);
1436 	return tmp;
1437 }
1438 
1439 struct tm *
1440 localtime(const time_t *const timep)
1441 {
1442 	return localtime_r(timep, &tm);
1443 }
1444 
1445 struct tm *
1446 localtime_rz(const timezone_t sp, const time_t * __restrict timep, struct tm *tmp)
1447 {
1448 	if (sp == NULL)
1449 		tmp = gmtsub(NULL, timep, 0, tmp);
1450 	else
1451 		tmp = localsub(sp, timep, 0, tmp);
1452 	if (tmp == NULL)
1453 		errno = EOVERFLOW;
1454 	return tmp;
1455 }
1456 
1457 /*
1458 ** gmtsub is to gmtime as localsub is to localtime.
1459 */
1460 
1461 static struct tm *
1462 gmtsub(const timezone_t sp, const time_t *const timep,
1463     const int_fast32_t offset, struct tm *const tmp)
1464 {
1465 	struct tm *	result;
1466 #ifdef _REENTRANT
1467 	static mutex_t gmt_mutex = MUTEX_INITIALIZER;
1468 #endif
1469 
1470 	mutex_lock(&gmt_mutex);
1471 	if (!gmt_is_set) {
1472 		int saveerrno;
1473 		gmt_is_set = TRUE;
1474 		saveerrno = errno;
1475 		gmtptr = malloc(sizeof *gmtptr);
1476 		errno = saveerrno;
1477 		if (gmtptr != NULL)
1478 			gmtload(gmtptr);
1479 	}
1480 	mutex_unlock(&gmt_mutex);
1481 	result = timesub(gmtptr, timep, offset, tmp);
1482 #ifdef TM_ZONE
1483 	/*
1484 	** Could get fancy here and deliver something such as
1485 	** "UT+xxxx" or "UT-xxxx" if offset is non-zero,
1486 	** but this is no time for a treasure hunt.
1487 	*/
1488 	tmp->TM_ZONE = offset ? __UNCONST(wildabbr) : gmtptr ? gmtptr->chars :
1489 	    __UNCONST(gmt);
1490 #endif /* defined TM_ZONE */
1491 	return result;
1492 }
1493 
1494 struct tm *
1495 gmtime(const time_t *const timep)
1496 {
1497 	struct tm *tmp = gmtsub(NULL, timep, 0, &tm);
1498 
1499 	if (tmp == NULL)
1500 		errno = EOVERFLOW;
1501 
1502 	return tmp;
1503 }
1504 
1505 /*
1506 ** Re-entrant version of gmtime.
1507 */
1508 
1509 struct tm *
1510 gmtime_r(const time_t * const timep, struct tm *tmp)
1511 {
1512 	tmp = gmtsub(NULL, timep, 0, tmp);
1513 
1514 	if (tmp == NULL)
1515 		errno = EOVERFLOW;
1516 
1517 	return tmp;
1518 }
1519 
1520 #ifdef STD_INSPIRED
1521 
1522 struct tm *
1523 offtime(const time_t *const timep, long offset)
1524 {
1525 	struct tm *tmp;
1526 
1527 	if ((offset > 0 && offset > INT_FAST32_MAX) ||
1528 	    (offset < 0 && offset < INT_FAST32_MIN)) {
1529 		errno = EOVERFLOW;
1530 		return NULL;
1531 	}
1532 	tmp = gmtsub(NULL, timep, (int_fast32_t)offset, &tm);
1533 
1534 	if (tmp == NULL)
1535 		errno = EOVERFLOW;
1536 
1537 	return tmp;
1538 }
1539 
1540 struct tm *
1541 offtime_r(const time_t *timep, long offset, struct tm *tmp)
1542 {
1543 	if ((offset > 0 && offset > INT_FAST32_MAX) ||
1544 	    (offset < 0 && offset < INT_FAST32_MIN)) {
1545 		errno = EOVERFLOW;
1546 		return NULL;
1547 	}
1548 	tmp = gmtsub(NULL, timep, (int_fast32_t)offset, tmp);
1549 
1550 	if (tmp == NULL)
1551 		errno = EOVERFLOW;
1552 
1553 	return tmp;
1554 }
1555 
1556 #endif /* defined STD_INSPIRED */
1557 
1558 /*
1559 ** Return the number of leap years through the end of the given year
1560 ** where, to make the math easy, the answer for year zero is defined as zero.
1561 */
1562 
1563 static int
1564 leaps_thru_end_of(const int y)
1565 {
1566 	return (y >= 0) ? (y / 4 - y / 100 + y / 400) :
1567 		-(leaps_thru_end_of(-(y + 1)) + 1);
1568 }
1569 
1570 static struct tm *
1571 timesub(const timezone_t sp, const time_t *const timep,
1572     const int_fast32_t offset, struct tm *const tmp)
1573 {
1574 	const struct lsinfo *	lp;
1575 	time_t			tdays;
1576 	int			idays;	/* unsigned would be so 2003 */
1577 	int_fast64_t		rem;
1578 	int			y;
1579 	const int *		ip;
1580 	int_fast64_t		corr;
1581 	int			hit;
1582 	int			i;
1583 
1584 	corr = 0;
1585 	hit = 0;
1586 	i = (sp == NULL) ? 0 : sp->leapcnt;
1587 	while (--i >= 0) {
1588 		lp = &sp->lsis[i];
1589 		if (*timep >= lp->ls_trans) {
1590 			if (*timep == lp->ls_trans) {
1591 				hit = ((i == 0 && lp->ls_corr > 0) ||
1592 					lp->ls_corr > sp->lsis[i - 1].ls_corr);
1593 				if (hit)
1594 					while (i > 0 &&
1595 						sp->lsis[i].ls_trans ==
1596 						sp->lsis[i - 1].ls_trans + 1 &&
1597 						sp->lsis[i].ls_corr ==
1598 						sp->lsis[i - 1].ls_corr + 1) {
1599 							++hit;
1600 							--i;
1601 					}
1602 			}
1603 			corr = lp->ls_corr;
1604 			break;
1605 		}
1606 	}
1607 	y = EPOCH_YEAR;
1608 	tdays = (time_t)(*timep / SECSPERDAY);
1609 	rem = (int_fast64_t) (*timep - tdays * SECSPERDAY);
1610 	while (tdays < 0 || tdays >= year_lengths[isleap(y)]) {
1611 		int		newy;
1612 		time_t	tdelta;
1613 		int	idelta;
1614 		int	leapdays;
1615 
1616 		tdelta = tdays / DAYSPERLYEAR;
1617 		if (! ((! TYPE_SIGNED(time_t) || INT_MIN <= tdelta)
1618 		       && tdelta <= INT_MAX))
1619 			return NULL;
1620 		_DIAGASSERT(__type_fit(int, tdelta));
1621 		idelta = (int)tdelta;
1622 		if (idelta == 0)
1623 			idelta = (tdays < 0) ? -1 : 1;
1624 		newy = y;
1625 		if (increment_overflow(&newy, idelta))
1626 			return NULL;
1627 		leapdays = leaps_thru_end_of(newy - 1) -
1628 			leaps_thru_end_of(y - 1);
1629 		tdays -= ((time_t) newy - y) * DAYSPERNYEAR;
1630 		tdays -= leapdays;
1631 		y = newy;
1632 	}
1633 	{
1634 		int_fast32_t seconds;
1635 
1636 		seconds = (int_fast32_t)(tdays * SECSPERDAY);
1637 		tdays = (time_t)(seconds / SECSPERDAY);
1638 		rem += (int_fast64_t)(seconds - tdays * SECSPERDAY);
1639 	}
1640 	/*
1641 	** Given the range, we can now fearlessly cast...
1642 	*/
1643 	idays = (int) tdays;
1644 	rem += offset - corr;
1645 	while (rem < 0) {
1646 		rem += SECSPERDAY;
1647 		--idays;
1648 	}
1649 	while (rem >= SECSPERDAY) {
1650 		rem -= SECSPERDAY;
1651 		++idays;
1652 	}
1653 	while (idays < 0) {
1654 		if (increment_overflow(&y, -1))
1655 			return NULL;
1656 		idays += year_lengths[isleap(y)];
1657 	}
1658 	while (idays >= year_lengths[isleap(y)]) {
1659 		idays -= year_lengths[isleap(y)];
1660 		if (increment_overflow(&y, 1))
1661 			return NULL;
1662 	}
1663 	tmp->tm_year = y;
1664 	if (increment_overflow(&tmp->tm_year, -TM_YEAR_BASE))
1665 		return NULL;
1666 	tmp->tm_yday = idays;
1667 	/*
1668 	** The "extra" mods below avoid overflow problems.
1669 	*/
1670 	tmp->tm_wday = EPOCH_WDAY +
1671 		((y - EPOCH_YEAR) % DAYSPERWEEK) *
1672 		(DAYSPERNYEAR % DAYSPERWEEK) +
1673 		leaps_thru_end_of(y - 1) -
1674 		leaps_thru_end_of(EPOCH_YEAR - 1) +
1675 		idays;
1676 	tmp->tm_wday %= DAYSPERWEEK;
1677 	if (tmp->tm_wday < 0)
1678 		tmp->tm_wday += DAYSPERWEEK;
1679 	tmp->tm_hour = (int) (rem / SECSPERHOUR);
1680 	rem %= SECSPERHOUR;
1681 	tmp->tm_min = (int) (rem / SECSPERMIN);
1682 	/*
1683 	** A positive leap second requires a special
1684 	** representation. This uses "... ??:59:60" et seq.
1685 	*/
1686 	tmp->tm_sec = (int) (rem % SECSPERMIN) + hit;
1687 	ip = mon_lengths[isleap(y)];
1688 	for (tmp->tm_mon = 0; idays >= ip[tmp->tm_mon]; ++(tmp->tm_mon))
1689 		idays -= ip[tmp->tm_mon];
1690 	tmp->tm_mday = (int) (idays + 1);
1691 	tmp->tm_isdst = 0;
1692 #ifdef TM_GMTOFF
1693 	tmp->TM_GMTOFF = offset;
1694 #endif /* defined TM_GMTOFF */
1695 	return tmp;
1696 }
1697 
1698 char *
1699 ctime(const time_t *const timep)
1700 {
1701 /*
1702 ** Section 4.12.3.2 of X3.159-1989 requires that
1703 **	The ctime function converts the calendar time pointed to by timer
1704 **	to local time in the form of a string. It is equivalent to
1705 **		asctime(localtime(timer))
1706 */
1707 	struct tm *rtm = localtime(timep);
1708 	if (rtm == NULL)
1709 		return NULL;
1710 	return asctime(rtm);
1711 }
1712 
1713 char *
1714 ctime_r(const time_t *const timep, char *buf)
1715 {
1716 	struct tm	mytm, *rtm;
1717 
1718 	rtm = localtime_r(timep, &mytm);
1719 	if (rtm == NULL)
1720 		return NULL;
1721 	return asctime_r(rtm, buf);
1722 }
1723 
1724 char *
1725 ctime_rz(const timezone_t sp, const time_t * timep, char *buf)
1726 {
1727 	struct tm	mytm, *rtm;
1728 
1729 	rtm = localtime_rz(sp, timep, &mytm);
1730 	if (rtm == NULL)
1731 		return NULL;
1732 	return asctime_r(rtm, buf);
1733 }
1734 
1735 /*
1736 ** Adapted from code provided by Robert Elz, who writes:
1737 **	The "best" way to do mktime I think is based on an idea of Bob
1738 **	Kridle's (so its said...) from a long time ago.
1739 **	It does a binary search of the time_t space. Since time_t's are
1740 **	just 32 bits, its a max of 32 iterations (even at 64 bits it
1741 **	would still be very reasonable).
1742 */
1743 
1744 #ifndef WRONG
1745 #define WRONG	((time_t)-1)
1746 #endif /* !defined WRONG */
1747 
1748 /*
1749 ** Simplified normalize logic courtesy Paul Eggert.
1750 */
1751 
1752 static int
1753 increment_overflow(int *const ip, int j)
1754 {
1755 	int	i = *ip;
1756 
1757 	/*
1758 	** If i >= 0 there can only be overflow if i + j > INT_MAX
1759 	** or if j > INT_MAX - i; given i >= 0, INT_MAX - i cannot overflow.
1760 	** If i < 0 there can only be overflow if i + j < INT_MIN
1761 	** or if j < INT_MIN - i; given i < 0, INT_MIN - i cannot overflow.
1762 	*/
1763 	if ((i >= 0) ? (j > INT_MAX - i) : (j < INT_MIN - i))
1764 		return TRUE;
1765 	*ip += j;
1766 	return FALSE;
1767 }
1768 
1769 static int
1770 increment_overflow32(int_fast32_t *const lp, int const m)
1771 {
1772 	int_fast32_t l = *lp;
1773 
1774 	if ((l >= 0) ? (m > INT_FAST32_MAX - l) : (m < INT_FAST32_MIN - l))
1775 		return TRUE;
1776 	*lp += m;
1777 	return FALSE;
1778 }
1779 
1780 static int
1781 increment_overflow_time(time_t *tp, int_fast32_t j)
1782 {
1783 	/*
1784 	** This is like
1785 	** 'if (! (time_t_min <= *tp + j && *tp + j <= time_t_max)) ...',
1786 	** except that it does the right thing even if *tp + j would overflow.
1787 	*/
1788 	if (! (j < 0
1789 	       ? (TYPE_SIGNED(time_t) ? time_t_min - j <= *tp : -1 - j < *tp)
1790 	       : *tp <= time_t_max - j))
1791 		return TRUE;
1792 	*tp += j;
1793 	return FALSE;
1794 }
1795 
1796 static int
1797 normalize_overflow(int *const tensptr, int *const unitsptr, const int base)
1798 {
1799 	int	tensdelta;
1800 
1801 	tensdelta = (*unitsptr >= 0) ?
1802 		(*unitsptr / base) :
1803 		(-1 - (-1 - *unitsptr) / base);
1804 	*unitsptr -= tensdelta * base;
1805 	return increment_overflow(tensptr, tensdelta);
1806 }
1807 
1808 static int
1809 normalize_overflow32(int_fast32_t *const tensptr, int *const unitsptr,
1810     const int base)
1811 {
1812 	int	tensdelta;
1813 
1814 	tensdelta = (*unitsptr >= 0) ?
1815 		(*unitsptr / base) :
1816 		(-1 - (-1 - *unitsptr) / base);
1817 	*unitsptr -= tensdelta * base;
1818 	return increment_overflow32(tensptr, tensdelta);
1819 }
1820 
1821 static int
1822 tmcomp(const struct tm *const atmp, const struct tm *const btmp)
1823 {
1824 	int	result;
1825 
1826 	if (atmp->tm_year != btmp->tm_year)
1827 		return atmp->tm_year < btmp->tm_year ? -1 : 1;
1828 	if ((result = (atmp->tm_mon - btmp->tm_mon)) == 0 &&
1829 		(result = (atmp->tm_mday - btmp->tm_mday)) == 0 &&
1830 		(result = (atmp->tm_hour - btmp->tm_hour)) == 0 &&
1831 		(result = (atmp->tm_min - btmp->tm_min)) == 0)
1832 			result = atmp->tm_sec - btmp->tm_sec;
1833 	return result;
1834 }
1835 
1836 static time_t
1837 time2sub(const timezone_t sp, struct tm *const tmp, subfun_t funcp,
1838     const int_fast32_t offset, int *const okayp, const int do_norm_secs)
1839 {
1840 	int			dir;
1841 	int			i, j;
1842 	int			saved_seconds;
1843 	int_fast32_t		li;
1844 	time_t			lo;
1845 	time_t			hi;
1846 #ifdef NO_ERROR_IN_DST_GAP
1847 	time_t			ilo;
1848 #endif
1849 	int_fast32_t		y;
1850 	time_t			newt;
1851 	time_t			t;
1852 	struct tm		yourtm, mytm;
1853 
1854 	*okayp = FALSE;
1855 	yourtm = *tmp;
1856 #ifdef NO_ERROR_IN_DST_GAP
1857 again:
1858 #endif
1859 	if (do_norm_secs) {
1860 		if (normalize_overflow(&yourtm.tm_min, &yourtm.tm_sec,
1861 		    SECSPERMIN))
1862 			goto overflow;
1863 	}
1864 	if (normalize_overflow(&yourtm.tm_hour, &yourtm.tm_min, MINSPERHOUR))
1865 		goto overflow;
1866 	if (normalize_overflow(&yourtm.tm_mday, &yourtm.tm_hour, HOURSPERDAY))
1867 		goto overflow;
1868 	y = yourtm.tm_year;
1869 	if (normalize_overflow32(&y, &yourtm.tm_mon, MONSPERYEAR))
1870 		goto overflow;
1871 	/*
1872 	** Turn y into an actual year number for now.
1873 	** It is converted back to an offset from TM_YEAR_BASE later.
1874 	*/
1875 	if (increment_overflow32(&y, TM_YEAR_BASE))
1876 		goto overflow;
1877 	while (yourtm.tm_mday <= 0) {
1878 		if (increment_overflow32(&y, -1))
1879 			goto overflow;
1880 		li = y + (1 < yourtm.tm_mon);
1881 		yourtm.tm_mday += year_lengths[isleap(li)];
1882 	}
1883 	while (yourtm.tm_mday > DAYSPERLYEAR) {
1884 		li = y + (1 < yourtm.tm_mon);
1885 		yourtm.tm_mday -= year_lengths[isleap(li)];
1886 		if (increment_overflow32(&y, 1))
1887 			goto overflow;
1888 	}
1889 	for ( ; ; ) {
1890 		i = mon_lengths[isleap(y)][yourtm.tm_mon];
1891 		if (yourtm.tm_mday <= i)
1892 			break;
1893 		yourtm.tm_mday -= i;
1894 		if (++yourtm.tm_mon >= MONSPERYEAR) {
1895 			yourtm.tm_mon = 0;
1896 			if (increment_overflow32(&y, 1))
1897 				goto overflow;
1898 		}
1899 	}
1900 	if (increment_overflow32(&y, -TM_YEAR_BASE))
1901 		goto overflow;
1902 	yourtm.tm_year = (int)y;
1903 	if (yourtm.tm_year != y)
1904 		goto overflow;
1905 	if (yourtm.tm_sec >= 0 && yourtm.tm_sec < SECSPERMIN)
1906 		saved_seconds = 0;
1907 	else if (y + TM_YEAR_BASE < EPOCH_YEAR) {
1908 		/*
1909 		** We can't set tm_sec to 0, because that might push the
1910 		** time below the minimum representable time.
1911 		** Set tm_sec to 59 instead.
1912 		** This assumes that the minimum representable time is
1913 		** not in the same minute that a leap second was deleted from,
1914 		** which is a safer assumption than using 58 would be.
1915 		*/
1916 		if (increment_overflow(&yourtm.tm_sec, 1 - SECSPERMIN))
1917 			goto overflow;
1918 		saved_seconds = yourtm.tm_sec;
1919 		yourtm.tm_sec = SECSPERMIN - 1;
1920 	} else {
1921 		saved_seconds = yourtm.tm_sec;
1922 		yourtm.tm_sec = 0;
1923 	}
1924 	/*
1925 	** Do a binary search (this works whatever time_t's type is).
1926 	*/
1927 	/* LINTED const not */
1928 	if (!TYPE_SIGNED(time_t)) {
1929 		lo = 0;
1930 		hi = lo - 1;
1931 	} else {
1932 		lo = 1;
1933 		for (i = 0; i < (int) TYPE_BIT(time_t) - 1; ++i)
1934 			lo *= 2;
1935 		hi = -(lo + 1);
1936 	}
1937 #ifdef NO_ERROR_IN_DST_GAP
1938 	ilo = lo;
1939 #endif
1940 	for ( ; ; ) {
1941 		t = lo / 2 + hi / 2;
1942 		if (t < lo)
1943 			t = lo;
1944 		else if (t > hi)
1945 			t = hi;
1946 		if ((*funcp)(sp, &t, offset, &mytm) == NULL) {
1947 			/*
1948 			** Assume that t is too extreme to be represented in
1949 			** a struct tm; arrange things so that it is less
1950 			** extreme on the next pass.
1951 			*/
1952 			dir = (t > 0) ? 1 : -1;
1953 		} else	dir = tmcomp(&mytm, &yourtm);
1954 		if (dir != 0) {
1955 			if (t == lo) {
1956 				if (t == time_t_max)
1957 					goto overflow;
1958 				++t;
1959 				++lo;
1960 			} else if (t == hi) {
1961 				if (t == time_t_min)
1962 					goto overflow;
1963 				--t;
1964 				--hi;
1965 			}
1966 #ifdef NO_ERROR_IN_DST_GAP
1967 			if (ilo != lo && lo - 1 == hi && yourtm.tm_isdst < 0 &&
1968 			    do_norm_secs) {
1969 				for (i = sp->typecnt - 1; i >= 0; --i) {
1970 					for (j = sp->typecnt - 1; j >= 0; --j) {
1971 						time_t off;
1972 						if (sp->ttis[j].tt_isdst ==
1973 						    sp->ttis[i].tt_isdst)
1974 							continue;
1975 						off = sp->ttis[j].tt_gmtoff -
1976 						    sp->ttis[i].tt_gmtoff;
1977 						yourtm.tm_sec += off < 0 ?
1978 						    -off : off;
1979 						goto again;
1980 					}
1981 				}
1982 			}
1983 #endif
1984 			if (lo > hi)
1985 				goto invalid;
1986 			if (dir > 0)
1987 				hi = t;
1988 			else	lo = t;
1989 			continue;
1990 		}
1991 		if (yourtm.tm_isdst < 0 || mytm.tm_isdst == yourtm.tm_isdst)
1992 			break;
1993 		/*
1994 		** Right time, wrong type.
1995 		** Hunt for right time, right type.
1996 		** It's okay to guess wrong since the guess
1997 		** gets checked.
1998 		*/
1999 		if (sp == NULL)
2000 			goto invalid;
2001 		for (i = sp->typecnt - 1; i >= 0; --i) {
2002 			if (sp->ttis[i].tt_isdst != yourtm.tm_isdst)
2003 				continue;
2004 			for (j = sp->typecnt - 1; j >= 0; --j) {
2005 				if (sp->ttis[j].tt_isdst == yourtm.tm_isdst)
2006 					continue;
2007 				newt = (time_t)(t + sp->ttis[j].tt_gmtoff -
2008 				    sp->ttis[i].tt_gmtoff);
2009 				if ((*funcp)(sp, &newt, offset, &mytm) == NULL)
2010 					continue;
2011 				if (tmcomp(&mytm, &yourtm) != 0)
2012 					continue;
2013 				if (mytm.tm_isdst != yourtm.tm_isdst)
2014 					continue;
2015 				/*
2016 				** We have a match.
2017 				*/
2018 				t = newt;
2019 				goto label;
2020 			}
2021 		}
2022 		goto invalid;
2023 	}
2024 label:
2025 	newt = t + saved_seconds;
2026 	if ((newt < t) != (saved_seconds < 0))
2027 		goto overflow;
2028 	t = newt;
2029 	if ((*funcp)(sp, &t, offset, tmp)) {
2030 		*okayp = TRUE;
2031 		return t;
2032 	}
2033 overflow:
2034 	errno = EOVERFLOW;
2035 	return WRONG;
2036 invalid:
2037 	errno = EINVAL;
2038 	return WRONG;
2039 }
2040 
2041 static time_t
2042 time2(const timezone_t sp, struct tm *const tmp, subfun_t funcp,
2043     const int_fast32_t offset, int *const okayp)
2044 {
2045 	time_t	t;
2046 
2047 	/*
2048 	** First try without normalization of seconds
2049 	** (in case tm_sec contains a value associated with a leap second).
2050 	** If that fails, try with normalization of seconds.
2051 	*/
2052 	t = time2sub(sp, tmp, funcp, offset, okayp, FALSE);
2053 	return *okayp ? t : time2sub(sp, tmp, funcp, offset, okayp, TRUE);
2054 }
2055 
2056 static time_t
2057 time1(const timezone_t sp, struct tm *const tmp, subfun_t funcp,
2058     const int_fast32_t offset)
2059 {
2060 	time_t			t;
2061 	int			samei, otheri;
2062 	int			sameind, otherind;
2063 	int			i;
2064 	int			nseen;
2065 	int				seen[TZ_MAX_TYPES];
2066 	int				types[TZ_MAX_TYPES];
2067 	int				okay;
2068 
2069 	if (tmp == NULL) {
2070 		errno = EINVAL;
2071 		return WRONG;
2072 	}
2073 	if (tmp->tm_isdst > 1)
2074 		tmp->tm_isdst = 1;
2075 	t = time2(sp, tmp, funcp, offset, &okay);
2076 	if (okay)
2077 		return t;
2078 	if (tmp->tm_isdst < 0)
2079 #ifdef PCTS
2080 		/*
2081 		** POSIX Conformance Test Suite code courtesy Grant Sullivan.
2082 		*/
2083 		tmp->tm_isdst = 0;	/* reset to std and try again */
2084 #else
2085 		return t;
2086 #endif /* !defined PCTS */
2087 	/*
2088 	** We're supposed to assume that somebody took a time of one type
2089 	** and did some math on it that yielded a "struct tm" that's bad.
2090 	** We try to divine the type they started from and adjust to the
2091 	** type they need.
2092 	*/
2093 	if (sp == NULL) {
2094 		errno = EINVAL;
2095 		return WRONG;
2096 	}
2097 	for (i = 0; i < sp->typecnt; ++i)
2098 		seen[i] = FALSE;
2099 	nseen = 0;
2100 	for (i = sp->timecnt - 1; i >= 0; --i)
2101 		if (!seen[sp->types[i]]) {
2102 			seen[sp->types[i]] = TRUE;
2103 			types[nseen++] = sp->types[i];
2104 		}
2105 	for (sameind = 0; sameind < nseen; ++sameind) {
2106 		samei = types[sameind];
2107 		if (sp->ttis[samei].tt_isdst != tmp->tm_isdst)
2108 			continue;
2109 		for (otherind = 0; otherind < nseen; ++otherind) {
2110 			otheri = types[otherind];
2111 			if (sp->ttis[otheri].tt_isdst == tmp->tm_isdst)
2112 				continue;
2113 			tmp->tm_sec += (int)(sp->ttis[otheri].tt_gmtoff -
2114 					sp->ttis[samei].tt_gmtoff);
2115 			tmp->tm_isdst = !tmp->tm_isdst;
2116 			t = time2(sp, tmp, funcp, offset, &okay);
2117 			if (okay)
2118 				return t;
2119 			tmp->tm_sec -= (int)(sp->ttis[otheri].tt_gmtoff -
2120 					sp->ttis[samei].tt_gmtoff);
2121 			tmp->tm_isdst = !tmp->tm_isdst;
2122 		}
2123 	}
2124 	errno = EOVERFLOW;
2125 	return WRONG;
2126 }
2127 
2128 time_t
2129 mktime_z(const timezone_t sp, struct tm *const tmp)
2130 {
2131 	time_t t;
2132 	if (sp == NULL)
2133 		t = time1(NULL, tmp, gmtsub, 0);
2134 	else
2135 		t = time1(sp, tmp, localsub, 0);
2136 	return t;
2137 }
2138 
2139 time_t
2140 mktime(struct tm *const tmp)
2141 {
2142 	time_t result;
2143 
2144 	rwlock_wrlock(&lcl_lock);
2145 	tzset_unlocked();
2146 	result = mktime_z(lclptr, tmp);
2147 	rwlock_unlock(&lcl_lock);
2148 	return result;
2149 }
2150 
2151 #ifdef STD_INSPIRED
2152 
2153 time_t
2154 timelocal_z(const timezone_t sp, struct tm *const tmp)
2155 {
2156 	if (tmp != NULL)
2157 		tmp->tm_isdst = -1;	/* in case it wasn't initialized */
2158 	return mktime_z(sp, tmp);
2159 }
2160 
2161 time_t
2162 timelocal(struct tm *const tmp)
2163 {
2164 	if (tmp != NULL)
2165 		tmp->tm_isdst = -1;	/* in case it wasn't initialized */
2166 	return mktime(tmp);
2167 }
2168 
2169 time_t
2170 timegm(struct tm *const tmp)
2171 {
2172 	time_t t;
2173 
2174 	if (tmp != NULL)
2175 		tmp->tm_isdst = 0;
2176 	t = time1(gmtptr, tmp, gmtsub, 0);
2177 	return t;
2178 }
2179 
2180 time_t
2181 timeoff(struct tm *const tmp, long offset)
2182 {
2183 	time_t t;
2184 
2185 	if ((offset > 0 && offset > INT_FAST32_MAX) ||
2186 	    (offset < 0 && offset < INT_FAST32_MIN)) {
2187 		errno = EOVERFLOW;
2188 		return -1;
2189 	}
2190 	if (tmp != NULL)
2191 		tmp->tm_isdst = 0;
2192 	t = time1(gmtptr, tmp, gmtsub, (int_fast32_t)offset);
2193 	return t;
2194 }
2195 
2196 #endif /* defined STD_INSPIRED */
2197 
2198 #ifdef CMUCS
2199 
2200 /*
2201 ** The following is supplied for compatibility with
2202 ** previous versions of the CMUCS runtime library.
2203 */
2204 
2205 long
2206 gtime(struct tm *const tmp)
2207 {
2208 	const time_t t = mktime(tmp);
2209 
2210 	if (t == WRONG)
2211 		return -1;
2212 	return t;
2213 }
2214 
2215 #endif /* defined CMUCS */
2216 
2217 /*
2218 ** XXX--is the below the right way to conditionalize??
2219 */
2220 
2221 #ifdef STD_INSPIRED
2222 
2223 /*
2224 ** IEEE Std 1003.1-1988 (POSIX) legislates that 536457599
2225 ** shall correspond to "Wed Dec 31 23:59:59 UTC 1986", which
2226 ** is not the case if we are accounting for leap seconds.
2227 ** So, we provide the following conversion routines for use
2228 ** when exchanging timestamps with POSIX conforming systems.
2229 */
2230 
2231 static int_fast64_t
2232 leapcorr(const timezone_t sp, time_t *timep)
2233 {
2234 	struct lsinfo * lp;
2235 	int		i;
2236 
2237 	i = sp->leapcnt;
2238 	while (--i >= 0) {
2239 		lp = &sp->lsis[i];
2240 		if (*timep >= lp->ls_trans)
2241 			return lp->ls_corr;
2242 	}
2243 	return 0;
2244 }
2245 
2246 time_t
2247 time2posix_z(const timezone_t sp, time_t t)
2248 {
2249 	return (time_t)(t - leapcorr(sp, &t));
2250 }
2251 
2252 time_t
2253 time2posix(time_t t)
2254 {
2255 	time_t result;
2256 	rwlock_wrlock(&lcl_lock);
2257 	tzset_unlocked();
2258 	result = (time_t)(t - leapcorr(lclptr, &t));
2259 	rwlock_unlock(&lcl_lock);
2260 	return (result);
2261 }
2262 
2263 time_t
2264 posix2time_z(const timezone_t sp, time_t t)
2265 {
2266 	time_t	x;
2267 	time_t	y;
2268 
2269 	/*
2270 	** For a positive leap second hit, the result
2271 	** is not unique. For a negative leap second
2272 	** hit, the corresponding time doesn't exist,
2273 	** so we return an adjacent second.
2274 	*/
2275 	x = (time_t)(t + leapcorr(sp, &t));
2276 	y = (time_t)(x - leapcorr(sp, &x));
2277 	if (y < t) {
2278 		do {
2279 			x++;
2280 			y = (time_t)(x - leapcorr(sp, &x));
2281 		} while (y < t);
2282 		if (t != y) {
2283 			return x - 1;
2284 		}
2285 	} else if (y > t) {
2286 		do {
2287 			--x;
2288 			y = (time_t)(x - leapcorr(sp, &x));
2289 		} while (y > t);
2290 		if (t != y) {
2291 			return x + 1;
2292 		}
2293 	}
2294 	return x;
2295 }
2296 
2297 
2298 
2299 time_t
2300 posix2time(time_t t)
2301 {
2302 	time_t result;
2303 
2304 	rwlock_wrlock(&lcl_lock);
2305 	tzset_unlocked();
2306 	result = posix2time_z(lclptr, t);
2307 	rwlock_unlock(&lcl_lock);
2308 	return result;
2309 }
2310 
2311 #endif /* defined STD_INSPIRED */
2312