xref: /netbsd-src/lib/libc/time/localtime.c (revision c5e820cae412164fcbee52f470436200af5358ea)
1 /*	$NetBSD: localtime.c,v 1.66 2012/03/13 21:13:48 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 1.66 2012/03/13 21:13:48 christos Exp $");
14 #endif
15 #endif /* LIBC_SCCS and not lint */
16 
17 /*
18 ** Leap second handling from Bradley White.
19 ** POSIX-style TZ environment variable handling from Guy Harris.
20 */
21 
22 /*LINTLIBRARY*/
23 
24 #include "namespace.h"
25 #include "private.h"
26 #include "tzfile.h"
27 #include "fcntl.h"
28 #include "reentrant.h"
29 
30 #if defined(__weak_alias)
31 __weak_alias(daylight,_daylight)
32 __weak_alias(tzname,_tzname)
33 #endif
34 
35 #include "float.h"	/* for FLT_MAX and DBL_MAX */
36 
37 #ifndef TZ_ABBR_MAX_LEN
38 #define TZ_ABBR_MAX_LEN	16
39 #endif /* !defined TZ_ABBR_MAX_LEN */
40 
41 #ifndef TZ_ABBR_CHAR_SET
42 #define TZ_ABBR_CHAR_SET \
43 	"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789 :+-._"
44 #endif /* !defined TZ_ABBR_CHAR_SET */
45 
46 #ifndef TZ_ABBR_ERR_CHAR
47 #define TZ_ABBR_ERR_CHAR	'_'
48 #endif /* !defined TZ_ABBR_ERR_CHAR */
49 
50 /*
51 ** SunOS 4.1.1 headers lack O_BINARY.
52 */
53 
54 #ifdef O_BINARY
55 #define OPEN_MODE	(O_RDONLY | O_BINARY)
56 #endif /* defined O_BINARY */
57 #ifndef O_BINARY
58 #define OPEN_MODE	O_RDONLY
59 #endif /* !defined O_BINARY */
60 
61 #ifndef WILDABBR
62 /*
63 ** Someone might make incorrect use of a time zone abbreviation:
64 **	1.	They might reference tzname[0] before calling tzset (explicitly
65 **		or implicitly).
66 **	2.	They might reference tzname[1] before calling tzset (explicitly
67 **		or implicitly).
68 **	3.	They might reference tzname[1] after setting to a time zone
69 **		in which Daylight Saving Time is never observed.
70 **	4.	They might reference tzname[0] after setting to a time zone
71 **		in which Standard Time is never observed.
72 **	5.	They might reference tm.TM_ZONE after calling offtime.
73 ** What's best to do in the above cases is open to debate;
74 ** for now, we just set things up so that in any of the five cases
75 ** WILDABBR is used. Another possibility: initialize tzname[0] to the
76 ** string "tzname[0] used before set", and similarly for the other cases.
77 ** And another: initialize tzname[0] to "ERA", with an explanation in the
78 ** manual page of what this "time zone abbreviation" means (doing this so
79 ** that tzname[0] has the "normal" length of three characters).
80 */
81 #define WILDABBR	"   "
82 #endif /* !defined WILDABBR */
83 
84 static const char	wildabbr[] = WILDABBR;
85 
86 static char		gmt[] = "GMT";
87 
88 /*
89 ** The DST rules to use if TZ has no rules and we can't load TZDEFRULES.
90 ** We default to US rules as of 1999-08-17.
91 ** POSIX 1003.1 section 8.1.1 says that the default DST rules are
92 ** implementation dependent; for historical reasons, US rules are a
93 ** common default.
94 */
95 #ifndef TZDEFRULESTRING
96 #define TZDEFRULESTRING ",M4.1.0,M10.5.0"
97 #endif /* !defined TZDEFDST */
98 
99 struct ttinfo {				/* time type information */
100 	long		tt_gmtoff;	/* UTC offset in seconds */
101 	int		tt_isdst;	/* used to set tm_isdst */
102 	int		tt_abbrind;	/* abbreviation list index */
103 	int		tt_ttisstd;	/* TRUE if transition is std time */
104 	int		tt_ttisgmt;	/* TRUE if transition is UTC */
105 };
106 
107 struct lsinfo {				/* leap second information */
108 	time_t		ls_trans;	/* transition time */
109 	long		ls_corr;	/* correction to apply */
110 };
111 
112 #define BIGGEST(a, b)	(((a) > (b)) ? (a) : (b))
113 
114 #ifdef TZNAME_MAX
115 #define MY_TZNAME_MAX	TZNAME_MAX
116 #endif /* defined TZNAME_MAX */
117 #ifndef TZNAME_MAX
118 #define MY_TZNAME_MAX	255
119 #endif /* !defined TZNAME_MAX */
120 
121 struct __state {
122 	int		leapcnt;
123 	int		timecnt;
124 	int		typecnt;
125 	int		charcnt;
126 	int		goback;
127 	int		goahead;
128 	time_t		ats[TZ_MAX_TIMES];
129 	unsigned char	types[TZ_MAX_TIMES];
130 	struct ttinfo	ttis[TZ_MAX_TYPES];
131 	char		chars[/*CONSTCOND*/BIGGEST(BIGGEST(TZ_MAX_CHARS + 1, sizeof gmt),
132 				(2 * (MY_TZNAME_MAX + 1)))];
133 	struct lsinfo	lsis[TZ_MAX_LEAPS];
134 };
135 
136 struct rule {
137 	int		r_type;		/* type of rule--see below */
138 	int		r_day;		/* day number of rule */
139 	int		r_week;		/* week number of rule */
140 	int		r_mon;		/* month number of rule */
141 	long		r_time;		/* transition time of rule */
142 };
143 
144 #define JULIAN_DAY		0	/* Jn - Julian day */
145 #define DAY_OF_YEAR		1	/* n - day of year */
146 #define MONTH_NTH_DAY_OF_WEEK	2	/* Mm.n.d - month, week, day of week */
147 
148 typedef struct tm *(*subfun_t)(const timezone_t sp, const time_t *timep,
149 			       long offset, struct tm *tmp);
150 
151 /*
152 ** Prototypes for static functions.
153 */
154 
155 static long		detzcode(const char * codep);
156 static time_t		detzcode64(const char * codep);
157 static int		differ_by_repeat(time_t t1, time_t t0);
158 static const char *	getzname(const char * strp);
159 static const char *	getqzname(const char * strp, const int delim);
160 static const char *	getnum(const char * strp, int * nump, int min,
161 				int max);
162 static const char *	getsecs(const char * strp, long * secsp);
163 static const char *	getoffset(const char * strp, long * offsetp);
164 static const char *	getrule(const char * strp, struct rule * rulep);
165 static void		gmtload(timezone_t sp);
166 static struct tm *	gmtsub(const timezone_t sp, const time_t *timep,
167 				long offset, struct tm * tmp);
168 static struct tm *	localsub(const timezone_t sp, const time_t *timep,
169 				long offset, struct tm *tmp);
170 static int		increment_overflow(int * number, int delta);
171 static int		leaps_thru_end_of(int y);
172 static int		long_increment_overflow(long * number, int delta);
173 static int		long_normalize_overflow(long * tensptr,
174 				int * unitsptr, int base);
175 static int		normalize_overflow(int * tensptr, int * unitsptr,
176 				int base);
177 static void		settzname(void);
178 static time_t		time1(const timezone_t sp, struct tm * const tmp,
179 				subfun_t funcp, long offset);
180 static time_t		time2(const timezone_t sp, struct tm * const tmp,
181 				subfun_t funcp,
182 				const long offset, int *const okayp);
183 static time_t		time2sub(const timezone_t sp, struct tm * consttmp,
184 				subfun_t funcp, const long offset,
185 				int *const okayp, const int do_norm_secs);
186 static struct tm *	timesub(const timezone_t sp, const time_t * timep,
187 				long offset, struct tm * tmp);
188 static int		tmcomp(const struct tm * atmp,
189 				const struct tm * btmp);
190 static time_t		transtime(time_t janfirst, int year,
191 				const struct rule * rulep, long offset);
192 static int		typesequiv(const timezone_t sp, int a, int b);
193 static int		tzload(timezone_t sp, const char * name,
194 				int doextend);
195 static int		tzparse(timezone_t sp, const char * name,
196 				int lastditch);
197 static void		tzset_unlocked(void);
198 static void		tzsetwall_unlocked(void);
199 static long		leapcorr(const timezone_t sp, time_t * timep);
200 
201 static timezone_t lclptr;
202 static timezone_t gmtptr;
203 
204 #ifndef TZ_STRLEN_MAX
205 #define TZ_STRLEN_MAX 255
206 #endif /* !defined TZ_STRLEN_MAX */
207 
208 static char		lcl_TZname[TZ_STRLEN_MAX + 1];
209 static int		lcl_is_set;
210 static int		gmt_is_set;
211 
212 #if !defined(__LIBC12_SOURCE__)
213 
214 __aconst char *		tzname[2] = {
215 	(__aconst char *)__UNCONST(wildabbr),
216 	(__aconst char *)__UNCONST(wildabbr)
217 };
218 
219 #else
220 
221 extern __aconst char *	tzname[2];
222 
223 #endif
224 
225 #ifdef _REENTRANT
226 static rwlock_t lcl_lock = RWLOCK_INITIALIZER;
227 #endif
228 
229 /*
230 ** Section 4.12.3 of X3.159-1989 requires that
231 **	Except for the strftime function, these functions [asctime,
232 **	ctime, gmtime, localtime] return values in one of two static
233 **	objects: a broken-down time structure and an array of char.
234 ** Thanks to Paul Eggert for noting this.
235 */
236 
237 static struct tm	tm;
238 
239 #ifdef USG_COMPAT
240 #if !defined(__LIBC12_SOURCE__)
241 long 			timezone = 0;
242 int			daylight = 0;
243 #else
244 extern int		daylight;
245 extern long		timezone __RENAME(__timezone13);
246 #endif
247 #endif /* defined USG_COMPAT */
248 
249 #ifdef ALTZONE
250 time_t			altzone = 0;
251 #endif /* defined ALTZONE */
252 
253 static long
254 detzcode(const char *const codep)
255 {
256 	long	result;
257 	int	i;
258 
259 	result = (codep[0] & 0x80) ? ~0L : 0;
260 	for (i = 0; i < 4; ++i)
261 		result = (result << 8) | (codep[i] & 0xff);
262 	return result;
263 }
264 
265 static time_t
266 detzcode64(const char *const codep)
267 {
268 	time_t	result;
269 	int	i;
270 
271 	result = (codep[0] & 0x80) ? -1 : 0;
272 	for (i = 0; i < 8; ++i)
273 		result = result * 256 + (codep[i] & 0xff);
274 	return result;
275 }
276 
277 const char *
278 tzgetname(const timezone_t sp, int isdst)
279 {
280 	int i;
281 	for (i = 0; i < sp->timecnt; ++i) {
282 		const struct ttinfo *const ttisp = &sp->ttis[sp->types[i]];
283 
284 		if (ttisp->tt_isdst == isdst)
285 			return &sp->chars[ttisp->tt_abbrind];
286 	}
287 	return NULL;
288 }
289 
290 static void
291 settzname_z(timezone_t sp)
292 {
293 	int			i;
294 
295 	/*
296 	** Scrub the abbreviations.
297 	** First, replace bogus characters.
298 	*/
299 	for (i = 0; i < sp->charcnt; ++i)
300 		if (strchr(TZ_ABBR_CHAR_SET, sp->chars[i]) == NULL)
301 			sp->chars[i] = TZ_ABBR_ERR_CHAR;
302 	/*
303 	** Second, truncate long abbreviations.
304 	*/
305 	for (i = 0; i < sp->typecnt; ++i) {
306 		const struct ttinfo * const	ttisp = &sp->ttis[i];
307 		char *				cp = &sp->chars[ttisp->tt_abbrind];
308 
309 		if (strlen(cp) > TZ_ABBR_MAX_LEN &&
310 			strcmp(cp, GRANDPARENTED) != 0)
311 				*(cp + TZ_ABBR_MAX_LEN) = '\0';
312 	}
313 }
314 
315 static void
316 settzname(void)
317 {
318 	timezone_t const	sp = lclptr;
319 	int			i;
320 
321 	tzname[0] = (__aconst char *)__UNCONST(wildabbr);
322 	tzname[1] = (__aconst char *)__UNCONST(wildabbr);
323 #ifdef USG_COMPAT
324 	daylight = 0;
325 	timezone = 0;
326 #endif /* defined USG_COMPAT */
327 #ifdef ALTZONE
328 	altzone = 0;
329 #endif /* defined ALTZONE */
330 	if (sp == NULL) {
331 		tzname[0] = tzname[1] = (__aconst char *)__UNCONST(gmt);
332 		return;
333 	}
334 	/*
335 	** And to get the latest zone names into tzname. . .
336 	*/
337 	for (i = 0; i < sp->typecnt; ++i) {
338 		const struct ttinfo * const	ttisp = &sp->ttis[i];
339 
340 		tzname[ttisp->tt_isdst] =
341 			&sp->chars[ttisp->tt_abbrind];
342 #ifdef USG_COMPAT
343 		if (ttisp->tt_isdst)
344 			daylight = 1;
345 		if (!ttisp->tt_isdst)
346 			timezone = -(ttisp->tt_gmtoff);
347 #endif /* defined USG_COMPAT */
348 #ifdef ALTZONE
349 		if (i == 0 || ttisp->tt_isdst)
350 			altzone = -(ttisp->tt_gmtoff);
351 #endif /* defined ALTZONE */
352 	}
353 	settzname_z(sp);
354 }
355 
356 static int
357 differ_by_repeat(const time_t t1, const time_t t0)
358 {
359 /* CONSTCOND */
360 	if (TYPE_INTEGRAL(time_t) &&
361 		TYPE_BIT(time_t) - TYPE_SIGNED(time_t) < SECSPERREPEAT_BITS)
362 			return 0;
363 	return (int_fast64_t)t1 - (int_fast64_t)t0 == SECSPERREPEAT;
364 }
365 
366 static int
367 tzload(timezone_t sp, const char *name, const int doextend)
368 {
369 	const char *		p;
370 	int			i;
371 	int			fid;
372 	int			stored;
373 	ssize_t			nread;
374 	typedef union {
375 		struct tzhead	tzhead;
376 		char		buf[2 * sizeof(struct tzhead) +
377 					2 * sizeof *sp +
378 					4 * TZ_MAX_TIMES];
379 	} u_t;
380 	u_t *			up;
381 
382 	up = calloc(1, sizeof *up);
383 	if (up == NULL)
384 		return -1;
385 
386 	sp->goback = sp->goahead = FALSE;
387 	if (name == NULL && (name = TZDEFAULT) == NULL)
388 		goto oops;
389 	{
390 		int	doaccess;
391 		/*
392 		** Section 4.9.1 of the C standard says that
393 		** "FILENAME_MAX expands to an integral constant expression
394 		** that is the size needed for an array of char large enough
395 		** to hold the longest file name string that the implementation
396 		** guarantees can be opened."
397 		*/
398 		char		fullname[FILENAME_MAX + 1];
399 
400 		if (name[0] == ':')
401 			++name;
402 		doaccess = name[0] == '/';
403 		if (!doaccess) {
404 			if ((p = TZDIR) == NULL)
405 				goto oops;
406 			if ((strlen(p) + strlen(name) + 1) >= sizeof fullname)
407 				goto oops;
408 			(void) strcpy(fullname, p);	/* XXX strcpy is safe */
409 			(void) strcat(fullname, "/");	/* XXX strcat is safe */
410 			(void) strcat(fullname, name);	/* XXX strcat is safe */
411 			/*
412 			** Set doaccess if '.' (as in "../") shows up in name.
413 			*/
414 			if (strchr(name, '.') != NULL)
415 				doaccess = TRUE;
416 			name = fullname;
417 		}
418 		if (doaccess && access(name, R_OK) != 0)
419 			goto oops;
420 		/*
421 		 * XXX potential security problem here if user of a set-id
422 		 * program has set TZ (which is passed in as name) here,
423 		 * and uses a race condition trick to defeat the access(2)
424 		 * above.
425 		 */
426 		if ((fid = open(name, OPEN_MODE)) == -1)
427 			goto oops;
428 	}
429 	nread = read(fid, up->buf, sizeof up->buf);
430 	if (close(fid) < 0 || nread <= 0)
431 		goto oops;
432 	for (stored = 4; stored <= 8; stored *= 2) {
433 		int		ttisstdcnt;
434 		int		ttisgmtcnt;
435 
436 		ttisstdcnt = (int) detzcode(up->tzhead.tzh_ttisstdcnt);
437 		ttisgmtcnt = (int) detzcode(up->tzhead.tzh_ttisgmtcnt);
438 		sp->leapcnt = (int) detzcode(up->tzhead.tzh_leapcnt);
439 		sp->timecnt = (int) detzcode(up->tzhead.tzh_timecnt);
440 		sp->typecnt = (int) detzcode(up->tzhead.tzh_typecnt);
441 		sp->charcnt = (int) detzcode(up->tzhead.tzh_charcnt);
442 		p = up->tzhead.tzh_charcnt + sizeof up->tzhead.tzh_charcnt;
443 		if (sp->leapcnt < 0 || sp->leapcnt > TZ_MAX_LEAPS ||
444 			sp->typecnt <= 0 || sp->typecnt > TZ_MAX_TYPES ||
445 			sp->timecnt < 0 || sp->timecnt > TZ_MAX_TIMES ||
446 			sp->charcnt < 0 || sp->charcnt > TZ_MAX_CHARS ||
447 			(ttisstdcnt != sp->typecnt && ttisstdcnt != 0) ||
448 			(ttisgmtcnt != sp->typecnt && ttisgmtcnt != 0))
449 				goto oops;
450 		if (nread - (p - up->buf) <
451 			sp->timecnt * stored +		/* ats */
452 			sp->timecnt +			/* types */
453 			sp->typecnt * 6 +		/* ttinfos */
454 			sp->charcnt +			/* chars */
455 			sp->leapcnt * (stored + 4) +	/* lsinfos */
456 			ttisstdcnt +			/* ttisstds */
457 			ttisgmtcnt)			/* ttisgmts */
458 				goto oops;
459 		for (i = 0; i < sp->timecnt; ++i) {
460 			sp->ats[i] = (time_t)((stored == 4) ?
461 				detzcode(p) : detzcode64(p));
462 			p += stored;
463 		}
464 		for (i = 0; i < sp->timecnt; ++i) {
465 			sp->types[i] = (unsigned char) *p++;
466 			if (sp->types[i] >= sp->typecnt)
467 				goto oops;
468 		}
469 		for (i = 0; i < sp->typecnt; ++i) {
470 			struct ttinfo *	ttisp;
471 
472 			ttisp = &sp->ttis[i];
473 			ttisp->tt_gmtoff = detzcode(p);
474 			p += 4;
475 			ttisp->tt_isdst = (unsigned char) *p++;
476 			if (ttisp->tt_isdst != 0 && ttisp->tt_isdst != 1)
477 				goto oops;
478 			ttisp->tt_abbrind = (unsigned char) *p++;
479 			if (ttisp->tt_abbrind < 0 ||
480 				ttisp->tt_abbrind > sp->charcnt)
481 					goto oops;
482 		}
483 		for (i = 0; i < sp->charcnt; ++i)
484 			sp->chars[i] = *p++;
485 		sp->chars[i] = '\0';	/* ensure '\0' at end */
486 		for (i = 0; i < sp->leapcnt; ++i) {
487 			struct lsinfo *	lsisp;
488 
489 			lsisp = &sp->lsis[i];
490 			lsisp->ls_trans = (time_t)((stored == 4) ?
491 			    detzcode(p) : detzcode64(p));
492 			p += stored;
493 			lsisp->ls_corr = detzcode(p);
494 			p += 4;
495 		}
496 		for (i = 0; i < sp->typecnt; ++i) {
497 			struct ttinfo *	ttisp;
498 
499 			ttisp = &sp->ttis[i];
500 			if (ttisstdcnt == 0)
501 				ttisp->tt_ttisstd = FALSE;
502 			else {
503 				ttisp->tt_ttisstd = *p++;
504 				if (ttisp->tt_ttisstd != TRUE &&
505 					ttisp->tt_ttisstd != FALSE)
506 						goto oops;
507 			}
508 		}
509 		for (i = 0; i < sp->typecnt; ++i) {
510 			struct ttinfo *	ttisp;
511 
512 			ttisp = &sp->ttis[i];
513 			if (ttisgmtcnt == 0)
514 				ttisp->tt_ttisgmt = FALSE;
515 			else {
516 				ttisp->tt_ttisgmt = *p++;
517 				if (ttisp->tt_ttisgmt != TRUE &&
518 					ttisp->tt_ttisgmt != FALSE)
519 						goto oops;
520 			}
521 		}
522 		/*
523 		** Out-of-sort ats should mean we're running on a
524 		** signed time_t system but using a data file with
525 		** unsigned values (or vice versa).
526 		*/
527 		for (i = 0; i < sp->timecnt - 2; ++i)
528 			if (sp->ats[i] > sp->ats[i + 1]) {
529 				++i;
530 /* CONSTCOND */
531 				if (TYPE_SIGNED(time_t)) {
532 					/*
533 					** Ignore the end (easy).
534 					*/
535 					sp->timecnt = i;
536 				} else {
537 					/*
538 					** Ignore the beginning (harder).
539 					*/
540 					int	j;
541 
542 					for (j = 0; j + i < sp->timecnt; ++j) {
543 						sp->ats[j] = sp->ats[j + i];
544 						sp->types[j] = sp->types[j + i];
545 					}
546 					sp->timecnt = j;
547 				}
548 				break;
549 			}
550 		/*
551 		** If this is an old file, we're done.
552 		*/
553 		if (up->tzhead.tzh_version[0] == '\0')
554 			break;
555 		nread -= p - up->buf;
556 		for (i = 0; i < nread; ++i)
557 			up->buf[i] = p[i];
558 		/*
559 		** If this is a narrow integer time_t system, we're done.
560 		*/
561 		if (stored >= (int) sizeof(time_t)
562 /* CONSTCOND */
563 				&& TYPE_INTEGRAL(time_t))
564 			break;
565 	}
566 	if (doextend && nread > 2 &&
567 		up->buf[0] == '\n' && up->buf[nread - 1] == '\n' &&
568 		sp->typecnt + 2 <= TZ_MAX_TYPES) {
569 			struct __state ts;
570 			int	result;
571 
572 			up->buf[nread - 1] = '\0';
573 			result = tzparse(&ts, &up->buf[1], FALSE);
574 			if (result == 0 && ts.typecnt == 2 &&
575 				sp->charcnt + ts.charcnt <= TZ_MAX_CHARS) {
576 					for (i = 0; i < 2; ++i)
577 						ts.ttis[i].tt_abbrind +=
578 							sp->charcnt;
579 					for (i = 0; i < ts.charcnt; ++i)
580 						sp->chars[sp->charcnt++] =
581 							ts.chars[i];
582 					i = 0;
583 					while (i < ts.timecnt &&
584 						ts.ats[i] <=
585 						sp->ats[sp->timecnt - 1])
586 							++i;
587 					while (i < ts.timecnt &&
588 					    sp->timecnt < TZ_MAX_TIMES) {
589 						sp->ats[sp->timecnt] =
590 							ts.ats[i];
591 						sp->types[sp->timecnt] =
592 							sp->typecnt +
593 							ts.types[i];
594 						++sp->timecnt;
595 						++i;
596 					}
597 					sp->ttis[sp->typecnt++] = ts.ttis[0];
598 					sp->ttis[sp->typecnt++] = ts.ttis[1];
599 			}
600 	}
601 	if (sp->timecnt > 1) {
602 		for (i = 1; i < sp->timecnt; ++i)
603 			if (typesequiv(sp, sp->types[i], sp->types[0]) &&
604 				differ_by_repeat(sp->ats[i], sp->ats[0])) {
605 					sp->goback = TRUE;
606 					break;
607 				}
608 		for (i = sp->timecnt - 2; i >= 0; --i)
609 			if (typesequiv(sp, sp->types[sp->timecnt - 1],
610 				sp->types[i]) &&
611 				differ_by_repeat(sp->ats[sp->timecnt - 1],
612 				sp->ats[i])) {
613 					sp->goahead = TRUE;
614 					break;
615 		}
616 	}
617 	free(up);
618 	return 0;
619 oops:
620 	free(up);
621 	return -1;
622 }
623 
624 static int
625 typesequiv(const timezone_t sp, const int a, const int b)
626 {
627 	int	result;
628 
629 	if (sp == NULL ||
630 		a < 0 || a >= sp->typecnt ||
631 		b < 0 || b >= sp->typecnt)
632 			result = FALSE;
633 	else {
634 		const struct ttinfo *	ap = &sp->ttis[a];
635 		const struct ttinfo *	bp = &sp->ttis[b];
636 		result = ap->tt_gmtoff == bp->tt_gmtoff &&
637 			ap->tt_isdst == bp->tt_isdst &&
638 			ap->tt_ttisstd == bp->tt_ttisstd &&
639 			ap->tt_ttisgmt == bp->tt_ttisgmt &&
640 			strcmp(&sp->chars[ap->tt_abbrind],
641 			&sp->chars[bp->tt_abbrind]) == 0;
642 	}
643 	return result;
644 }
645 
646 static const int	mon_lengths[2][MONSPERYEAR] = {
647 	{ 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 },
648 	{ 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }
649 };
650 
651 static const int	year_lengths[2] = {
652 	DAYSPERNYEAR, DAYSPERLYEAR
653 };
654 
655 /*
656 ** Given a pointer into a time zone string, scan until a character that is not
657 ** a valid character in a zone name is found. Return a pointer to that
658 ** character.
659 */
660 
661 static const char *
662 getzname(strp)
663 const char *	strp;
664 {
665 	char	c;
666 
667 	while ((c = *strp) != '\0' && !is_digit(c) && c != ',' && c != '-' &&
668 		c != '+')
669 			++strp;
670 	return strp;
671 }
672 
673 /*
674 ** Given a pointer into an extended time zone string, scan until the ending
675 ** delimiter of the zone name is located. Return a pointer to the delimiter.
676 **
677 ** As with getzname above, the legal character set is actually quite
678 ** restricted, with other characters producing undefined results.
679 ** We don't do any checking here; checking is done later in common-case code.
680 */
681 
682 static const char *
683 getqzname(const char *strp, const int delim)
684 {
685 	int	c;
686 
687 	while ((c = *strp) != '\0' && c != delim)
688 		++strp;
689 	return strp;
690 }
691 
692 /*
693 ** Given a pointer into a time zone string, extract a number from that string.
694 ** Check that the number is within a specified range; if it is not, return
695 ** NULL.
696 ** Otherwise, return a pointer to the first character not part of the number.
697 */
698 
699 static const char *
700 getnum(strp, nump, min, max)
701 const char *	strp;
702 int * const		nump;
703 const int		min;
704 const int		max;
705 {
706 	char	c;
707 	int	num;
708 
709 	if (strp == NULL || !is_digit(c = *strp)) {
710 		errno = EINVAL;
711 		return NULL;
712 	}
713 	num = 0;
714 	do {
715 		num = num * 10 + (c - '0');
716 		if (num > max) {
717 			errno = EOVERFLOW;
718 			return NULL;	/* illegal value */
719 		}
720 		c = *++strp;
721 	} while (is_digit(c));
722 	if (num < min) {
723 		errno = EINVAL;
724 		return NULL;		/* illegal value */
725 	}
726 	*nump = num;
727 	return strp;
728 }
729 
730 /*
731 ** Given a pointer into a time zone string, extract a number of seconds,
732 ** in hh[:mm[:ss]] form, from the string.
733 ** If any error occurs, return NULL.
734 ** Otherwise, return a pointer to the first character not part of the number
735 ** of seconds.
736 */
737 
738 static const char *
739 getsecs(const char *strp, long *const secsp)
740 {
741 	int	num;
742 
743 	/*
744 	** `HOURSPERDAY * DAYSPERWEEK - 1' allows quasi-Posix rules like
745 	** "M10.4.6/26", which does not conform to Posix,
746 	** but which specifies the equivalent of
747 	** ``02:00 on the first Sunday on or after 23 Oct''.
748 	*/
749 	strp = getnum(strp, &num, 0, HOURSPERDAY * DAYSPERWEEK - 1);
750 	if (strp == NULL)
751 		return NULL;
752 	*secsp = num * (long) SECSPERHOUR;
753 	if (*strp == ':') {
754 		++strp;
755 		strp = getnum(strp, &num, 0, MINSPERHOUR - 1);
756 		if (strp == NULL)
757 			return NULL;
758 		*secsp += num * SECSPERMIN;
759 		if (*strp == ':') {
760 			++strp;
761 			/* `SECSPERMIN' allows for leap seconds. */
762 			strp = getnum(strp, &num, 0, SECSPERMIN);
763 			if (strp == NULL)
764 				return NULL;
765 			*secsp += num;
766 		}
767 	}
768 	return strp;
769 }
770 
771 /*
772 ** Given a pointer into a time zone string, extract an offset, in
773 ** [+-]hh[:mm[:ss]] form, from the string.
774 ** If any error occurs, return NULL.
775 ** Otherwise, return a pointer to the first character not part of the time.
776 */
777 
778 static const char *
779 getoffset(const char *strp, long *const offsetp)
780 {
781 	int	neg = 0;
782 
783 	if (*strp == '-') {
784 		neg = 1;
785 		++strp;
786 	} else if (*strp == '+')
787 		++strp;
788 	strp = getsecs(strp, offsetp);
789 	if (strp == NULL)
790 		return NULL;		/* illegal time */
791 	if (neg)
792 		*offsetp = -*offsetp;
793 	return strp;
794 }
795 
796 /*
797 ** Given a pointer into a time zone string, extract a rule in the form
798 ** date[/time]. See POSIX section 8 for the format of "date" and "time".
799 ** If a valid rule is not found, return NULL.
800 ** Otherwise, return a pointer to the first character not part of the rule.
801 */
802 
803 static const char *
804 getrule(const char *strp, struct rule *const rulep)
805 {
806 	if (*strp == 'J') {
807 		/*
808 		** Julian day.
809 		*/
810 		rulep->r_type = JULIAN_DAY;
811 		++strp;
812 		strp = getnum(strp, &rulep->r_day, 1, DAYSPERNYEAR);
813 	} else if (*strp == 'M') {
814 		/*
815 		** Month, week, day.
816 		*/
817 		rulep->r_type = MONTH_NTH_DAY_OF_WEEK;
818 		++strp;
819 		strp = getnum(strp, &rulep->r_mon, 1, MONSPERYEAR);
820 		if (strp == NULL)
821 			return NULL;
822 		if (*strp++ != '.')
823 			return NULL;
824 		strp = getnum(strp, &rulep->r_week, 1, 5);
825 		if (strp == NULL)
826 			return NULL;
827 		if (*strp++ != '.')
828 			return NULL;
829 		strp = getnum(strp, &rulep->r_day, 0, DAYSPERWEEK - 1);
830 	} else if (is_digit(*strp)) {
831 		/*
832 		** Day of year.
833 		*/
834 		rulep->r_type = DAY_OF_YEAR;
835 		strp = getnum(strp, &rulep->r_day, 0, DAYSPERLYEAR - 1);
836 	} else	return NULL;		/* invalid format */
837 	if (strp == NULL)
838 		return NULL;
839 	if (*strp == '/') {
840 		/*
841 		** Time specified.
842 		*/
843 		++strp;
844 		strp = getsecs(strp, &rulep->r_time);
845 	} else	rulep->r_time = 2 * SECSPERHOUR;	/* default = 2:00:00 */
846 	return strp;
847 }
848 
849 /*
850 ** Given the Epoch-relative time of January 1, 00:00:00 UTC, in a year, the
851 ** year, a rule, and the offset from UTC at the time that rule takes effect,
852 ** calculate the Epoch-relative time that rule takes effect.
853 */
854 
855 static time_t
856 transtime(const time_t janfirst, const int year, const struct rule *const rulep,
857     const long offset)
858 {
859 	int	leapyear;
860 	time_t	value;
861 	int	i;
862 	int		d, m1, yy0, yy1, yy2, dow;
863 
864 	INITIALIZE(value);
865 	leapyear = isleap(year);
866 	switch (rulep->r_type) {
867 
868 	case JULIAN_DAY:
869 		/*
870 		** Jn - Julian day, 1 == January 1, 60 == March 1 even in leap
871 		** years.
872 		** In non-leap years, or if the day number is 59 or less, just
873 		** add SECSPERDAY times the day number-1 to the time of
874 		** January 1, midnight, to get the day.
875 		*/
876 		value = (time_t)(janfirst + (rulep->r_day - 1) * SECSPERDAY);
877 		if (leapyear && rulep->r_day >= 60)
878 			value += SECSPERDAY;
879 		break;
880 
881 	case DAY_OF_YEAR:
882 		/*
883 		** n - day of year.
884 		** Just add SECSPERDAY times the day number to the time of
885 		** January 1, midnight, to get the day.
886 		*/
887 		value = (time_t)(janfirst + rulep->r_day * SECSPERDAY);
888 		break;
889 
890 	case MONTH_NTH_DAY_OF_WEEK:
891 		/*
892 		** Mm.n.d - nth "dth day" of month m.
893 		*/
894 		value = janfirst;
895 		for (i = 0; i < rulep->r_mon - 1; ++i)
896 			value += (time_t)(mon_lengths[leapyear][i] * SECSPERDAY);
897 
898 		/*
899 		** Use Zeller's Congruence to get day-of-week of first day of
900 		** month.
901 		*/
902 		m1 = (rulep->r_mon + 9) % 12 + 1;
903 		yy0 = (rulep->r_mon <= 2) ? (year - 1) : year;
904 		yy1 = yy0 / 100;
905 		yy2 = yy0 % 100;
906 		dow = ((26 * m1 - 2) / 10 +
907 			1 + yy2 + yy2 / 4 + yy1 / 4 - 2 * yy1) % 7;
908 		if (dow < 0)
909 			dow += DAYSPERWEEK;
910 
911 		/*
912 		** "dow" is the day-of-week of the first day of the month. Get
913 		** the day-of-month (zero-origin) of the first "dow" day of the
914 		** month.
915 		*/
916 		d = rulep->r_day - dow;
917 		if (d < 0)
918 			d += DAYSPERWEEK;
919 		for (i = 1; i < rulep->r_week; ++i) {
920 			if (d + DAYSPERWEEK >=
921 				mon_lengths[leapyear][rulep->r_mon - 1])
922 					break;
923 			d += DAYSPERWEEK;
924 		}
925 
926 		/*
927 		** "d" is the day-of-month (zero-origin) of the day we want.
928 		*/
929 		value += (time_t)(d * SECSPERDAY);
930 		break;
931 	}
932 
933 	/*
934 	** "value" is the Epoch-relative time of 00:00:00 UTC on the day in
935 	** question. To get the Epoch-relative time of the specified local
936 	** time on that day, add the transition time and the current offset
937 	** from UTC.
938 	*/
939 	return (time_t)(value + rulep->r_time + offset);
940 }
941 
942 /*
943 ** Given a POSIX section 8-style TZ string, fill in the rule tables as
944 ** appropriate.
945 */
946 
947 static int
948 tzparse(timezone_t sp, const char *name, const int lastditch)
949 {
950 	const char *			stdname;
951 	const char *			dstname;
952 	size_t				stdlen;
953 	size_t				dstlen;
954 	long				stdoffset;
955 	long				dstoffset;
956 	time_t *		atp;
957 	unsigned char *	typep;
958 	char *			cp;
959 	int			load_result;
960 
961 	INITIALIZE(dstname);
962 	stdname = name;
963 	if (lastditch) {
964 		stdlen = strlen(name);	/* length of standard zone name */
965 		name += stdlen;
966 		if (stdlen >= sizeof sp->chars)
967 			stdlen = (sizeof sp->chars) - 1;
968 		stdoffset = 0;
969 	} else {
970 		if (*name == '<') {
971 			name++;
972 			stdname = name;
973 			name = getqzname(name, '>');
974 			if (*name != '>')
975 				return (-1);
976 			stdlen = name - stdname;
977 			name++;
978 		} else {
979 			name = getzname(name);
980 			stdlen = name - stdname;
981 		}
982 		if (*name == '\0')
983 			return -1;
984 		name = getoffset(name, &stdoffset);
985 		if (name == NULL)
986 			return -1;
987 	}
988 	load_result = tzload(sp, TZDEFRULES, FALSE);
989 	if (load_result != 0)
990 		sp->leapcnt = 0;		/* so, we're off a little */
991 	if (*name != '\0') {
992 		if (*name == '<') {
993 			dstname = ++name;
994 			name = getqzname(name, '>');
995 			if (*name != '>')
996 				return -1;
997 			dstlen = name - dstname;
998 			name++;
999 		} else {
1000 			dstname = name;
1001 			name = getzname(name);
1002 			dstlen = name - dstname; /* length of DST zone name */
1003 		}
1004 		if (*name != '\0' && *name != ',' && *name != ';') {
1005 			name = getoffset(name, &dstoffset);
1006 			if (name == NULL)
1007 				return -1;
1008 		} else	dstoffset = stdoffset - SECSPERHOUR;
1009 		if (*name == '\0' && load_result != 0)
1010 			name = TZDEFRULESTRING;
1011 		if (*name == ',' || *name == ';') {
1012 			struct rule	start;
1013 			struct rule	end;
1014 			int	year;
1015 			time_t	janfirst;
1016 			time_t		starttime;
1017 			time_t		endtime;
1018 
1019 			++name;
1020 			if ((name = getrule(name, &start)) == NULL)
1021 				return -1;
1022 			if (*name++ != ',')
1023 				return -1;
1024 			if ((name = getrule(name, &end)) == NULL)
1025 				return -1;
1026 			if (*name != '\0')
1027 				return -1;
1028 			sp->typecnt = 2;	/* standard time and DST */
1029 			/*
1030 			** Two transitions per year, from EPOCH_YEAR forward.
1031 			*/
1032 			memset(sp->ttis, 0, sizeof(sp->ttis));
1033 			sp->ttis[0].tt_gmtoff = -dstoffset;
1034 			sp->ttis[0].tt_isdst = 1;
1035 			sp->ttis[0].tt_abbrind = (int)(stdlen + 1);
1036 			sp->ttis[1].tt_gmtoff = -stdoffset;
1037 			sp->ttis[1].tt_isdst = 0;
1038 			sp->ttis[1].tt_abbrind = 0;
1039 			atp = sp->ats;
1040 			typep = sp->types;
1041 			janfirst = 0;
1042 			sp->timecnt = 0;
1043 			for (year = EPOCH_YEAR;
1044 			    sp->timecnt + 2 <= TZ_MAX_TIMES;
1045 			    ++year) {
1046 			    	time_t	newfirst;
1047 
1048 				starttime = transtime(janfirst, year, &start,
1049 					stdoffset);
1050 				endtime = transtime(janfirst, year, &end,
1051 					dstoffset);
1052 				if (starttime > endtime) {
1053 					*atp++ = endtime;
1054 					*typep++ = 1;	/* DST ends */
1055 					*atp++ = starttime;
1056 					*typep++ = 0;	/* DST begins */
1057 				} else {
1058 					*atp++ = starttime;
1059 					*typep++ = 0;	/* DST begins */
1060 					*atp++ = endtime;
1061 					*typep++ = 1;	/* DST ends */
1062 				}
1063 				sp->timecnt += 2;
1064 				newfirst = janfirst;
1065 				newfirst += (time_t)
1066 				    (year_lengths[isleap(year)] * SECSPERDAY);
1067 				if (newfirst <= janfirst)
1068 					break;
1069 				janfirst = newfirst;
1070 			}
1071 		} else {
1072 			long	theirstdoffset;
1073 			long	theirdstoffset;
1074 			long	theiroffset;
1075 			int	isdst;
1076 			int	i;
1077 			int	j;
1078 
1079 			if (*name != '\0')
1080 				return -1;
1081 			/*
1082 			** Initial values of theirstdoffset
1083 			*/
1084 			theirstdoffset = 0;
1085 			for (i = 0; i < sp->timecnt; ++i) {
1086 				j = sp->types[i];
1087 				if (!sp->ttis[j].tt_isdst) {
1088 					theirstdoffset =
1089 						-sp->ttis[j].tt_gmtoff;
1090 					break;
1091 				}
1092 			}
1093 			theirdstoffset = 0;
1094 			for (i = 0; i < sp->timecnt; ++i) {
1095 				j = sp->types[i];
1096 				if (sp->ttis[j].tt_isdst) {
1097 					theirdstoffset =
1098 						-sp->ttis[j].tt_gmtoff;
1099 					break;
1100 				}
1101 			}
1102 			/*
1103 			** Initially we're assumed to be in standard time.
1104 			*/
1105 			isdst = FALSE;
1106 			theiroffset = theirstdoffset;
1107 			/*
1108 			** Now juggle transition times and types
1109 			** tracking offsets as you do.
1110 			*/
1111 			for (i = 0; i < sp->timecnt; ++i) {
1112 				j = sp->types[i];
1113 				sp->types[i] = sp->ttis[j].tt_isdst;
1114 				if (sp->ttis[j].tt_ttisgmt) {
1115 					/* No adjustment to transition time */
1116 				} else {
1117 					/*
1118 					** If summer time is in effect, and the
1119 					** transition time was not specified as
1120 					** standard time, add the summer time
1121 					** offset to the transition time;
1122 					** otherwise, add the standard time
1123 					** offset to the transition time.
1124 					*/
1125 					/*
1126 					** Transitions from DST to DDST
1127 					** will effectively disappear since
1128 					** POSIX provides for only one DST
1129 					** offset.
1130 					*/
1131 					if (isdst && !sp->ttis[j].tt_ttisstd) {
1132 						sp->ats[i] += (time_t)
1133 						    (dstoffset - theirdstoffset);
1134 					} else {
1135 						sp->ats[i] += (time_t)
1136 						    (stdoffset - theirstdoffset);
1137 					}
1138 				}
1139 				theiroffset = -sp->ttis[j].tt_gmtoff;
1140 				if (!sp->ttis[j].tt_isdst)
1141 					theirstdoffset = theiroffset;
1142 				else	theirdstoffset = theiroffset;
1143 			}
1144 			/*
1145 			** Finally, fill in ttis.
1146 			*/
1147 			memset(sp->ttis, 0, sizeof(sp->ttis));
1148 			sp->ttis[0].tt_gmtoff = -stdoffset;
1149 			sp->ttis[0].tt_isdst = FALSE;
1150 			sp->ttis[0].tt_abbrind = 0;
1151 			sp->ttis[1].tt_gmtoff = -dstoffset;
1152 			sp->ttis[1].tt_isdst = TRUE;
1153 			sp->ttis[1].tt_abbrind = (int)(stdlen + 1);
1154 			sp->typecnt = 2;
1155 		}
1156 	} else {
1157 		dstlen = 0;
1158 		sp->typecnt = 1;		/* only standard time */
1159 		sp->timecnt = 0;
1160 		memset(sp->ttis, 0, sizeof(sp->ttis));
1161 		sp->ttis[0].tt_gmtoff = -stdoffset;
1162 		sp->ttis[0].tt_isdst = 0;
1163 		sp->ttis[0].tt_abbrind = 0;
1164 	}
1165 	sp->charcnt = (int)(stdlen + 1);
1166 	if (dstlen != 0)
1167 		sp->charcnt += (int)(dstlen + 1);
1168 	if ((size_t) sp->charcnt > sizeof sp->chars)
1169 		return -1;
1170 	cp = sp->chars;
1171 	(void) strncpy(cp, stdname, stdlen);
1172 	cp += stdlen;
1173 	*cp++ = '\0';
1174 	if (dstlen != 0) {
1175 		(void) strncpy(cp, dstname, dstlen);
1176 		*(cp + dstlen) = '\0';
1177 	}
1178 	return 0;
1179 }
1180 
1181 static void
1182 gmtload(timezone_t sp)
1183 {
1184 	if (tzload(sp, gmt, TRUE) != 0)
1185 		(void) tzparse(sp, gmt, TRUE);
1186 }
1187 
1188 timezone_t
1189 tzalloc(const char *name)
1190 {
1191 	timezone_t sp = calloc(1, sizeof *sp);
1192 	if (sp == NULL)
1193 		return NULL;
1194 	if (tzload(sp, name, TRUE) != 0) {
1195 		free(sp);
1196 		return NULL;
1197 	}
1198 	settzname_z(sp);
1199 	return sp;
1200 }
1201 
1202 void
1203 tzfree(const timezone_t sp)
1204 {
1205 	free(sp);
1206 }
1207 
1208 static void
1209 tzsetwall_unlocked(void)
1210 {
1211 	if (lcl_is_set < 0)
1212 		return;
1213 	lcl_is_set = -1;
1214 
1215 	if (lclptr == NULL) {
1216 		int saveerrno = errno;
1217 		lclptr = calloc(1, sizeof *lclptr);
1218 		errno = saveerrno;
1219 		if (lclptr == NULL) {
1220 			settzname();	/* all we can do */
1221 			return;
1222 		}
1223 	}
1224 	if (tzload(lclptr, NULL, TRUE) != 0)
1225 		gmtload(lclptr);
1226 	settzname();
1227 }
1228 
1229 #ifndef STD_INSPIRED
1230 /*
1231 ** A non-static declaration of tzsetwall in a system header file
1232 ** may cause a warning about this upcoming static declaration...
1233 */
1234 static
1235 #endif /* !defined STD_INSPIRED */
1236 void
1237 tzsetwall(void)
1238 {
1239 	rwlock_wrlock(&lcl_lock);
1240 	tzsetwall_unlocked();
1241 	rwlock_unlock(&lcl_lock);
1242 }
1243 
1244 #ifndef STD_INSPIRED
1245 /*
1246 ** A non-static declaration of tzsetwall in a system header file
1247 ** may cause a warning about this upcoming static declaration...
1248 */
1249 static
1250 #endif /* !defined STD_INSPIRED */
1251 void
1252 tzset_unlocked(void)
1253 {
1254 	const char *	name;
1255 	int saveerrno;
1256 
1257 	saveerrno = errno;
1258 	name = getenv("TZ");
1259 	errno = saveerrno;
1260 	if (name == NULL) {
1261 		tzsetwall_unlocked();
1262 		return;
1263 	}
1264 
1265 	if (lcl_is_set > 0 && strcmp(lcl_TZname, name) == 0)
1266 		return;
1267 	lcl_is_set = strlen(name) < sizeof lcl_TZname;
1268 	if (lcl_is_set)
1269 		(void)strlcpy(lcl_TZname, name, sizeof(lcl_TZname));
1270 
1271 	if (lclptr == NULL) {
1272 		saveerrno = errno;
1273 		lclptr = calloc(1, sizeof *lclptr);
1274 		errno = saveerrno;
1275 		if (lclptr == NULL) {
1276 			settzname();	/* all we can do */
1277 			return;
1278 		}
1279 	}
1280 	if (*name == '\0') {
1281 		/*
1282 		** User wants it fast rather than right.
1283 		*/
1284 		lclptr->leapcnt = 0;		/* so, we're off a little */
1285 		lclptr->timecnt = 0;
1286 		lclptr->typecnt = 0;
1287 		lclptr->ttis[0].tt_isdst = 0;
1288 		lclptr->ttis[0].tt_gmtoff = 0;
1289 		lclptr->ttis[0].tt_abbrind = 0;
1290 		(void) strlcpy(lclptr->chars, gmt, sizeof(lclptr->chars));
1291 	} else if (tzload(lclptr, name, TRUE) != 0)
1292 		if (name[0] == ':' || tzparse(lclptr, name, FALSE) != 0)
1293 			(void) gmtload(lclptr);
1294 	settzname();
1295 }
1296 
1297 void
1298 tzset(void)
1299 {
1300 	rwlock_wrlock(&lcl_lock);
1301 	tzset_unlocked();
1302 	rwlock_unlock(&lcl_lock);
1303 }
1304 
1305 /*
1306 ** The easy way to behave "as if no library function calls" localtime
1307 ** is to not call it--so we drop its guts into "localsub", which can be
1308 ** freely called. (And no, the PANS doesn't require the above behavior--
1309 ** but it *is* desirable.)
1310 **
1311 ** The unused offset argument is for the benefit of mktime variants.
1312 */
1313 
1314 /*ARGSUSED*/
1315 static struct tm *
1316 localsub(const timezone_t sp, const time_t * const timep, const long offset,
1317     struct tm *const tmp)
1318 {
1319 	const struct ttinfo *	ttisp;
1320 	int			i;
1321 	struct tm *		result;
1322 	const time_t			t = *timep;
1323 
1324 	if ((sp->goback && t < sp->ats[0]) ||
1325 		(sp->goahead && t > sp->ats[sp->timecnt - 1])) {
1326 			time_t			newt = t;
1327 			time_t		seconds;
1328 			time_t		tcycles;
1329 			int_fast64_t	icycles;
1330 
1331 			if (t < sp->ats[0])
1332 				seconds = sp->ats[0] - t;
1333 			else	seconds = t - sp->ats[sp->timecnt - 1];
1334 			--seconds;
1335 			tcycles = (time_t)
1336 			    (seconds / YEARSPERREPEAT / AVGSECSPERYEAR);
1337 			++tcycles;
1338 			icycles = tcycles;
1339 			if (tcycles - icycles >= 1 || icycles - tcycles >= 1)
1340 				return NULL;
1341 			seconds = (time_t) icycles;
1342 			seconds *= YEARSPERREPEAT;
1343 			seconds *= AVGSECSPERYEAR;
1344 			if (t < sp->ats[0])
1345 				newt += seconds;
1346 			else	newt -= seconds;
1347 			if (newt < sp->ats[0] ||
1348 				newt > sp->ats[sp->timecnt - 1])
1349 					return NULL;	/* "cannot happen" */
1350 			result = localsub(sp, &newt, offset, tmp);
1351 			if (result == tmp) {
1352 				time_t	newy;
1353 
1354 				newy = tmp->tm_year;
1355 				if (t < sp->ats[0])
1356 					newy -= (time_t)icycles * YEARSPERREPEAT;
1357 				else	newy += (time_t)icycles * YEARSPERREPEAT;
1358 				tmp->tm_year = (int)newy;
1359 				if (tmp->tm_year != newy)
1360 					return NULL;
1361 			}
1362 			return result;
1363 	}
1364 	if (sp->timecnt == 0 || t < sp->ats[0]) {
1365 		i = 0;
1366 		while (sp->ttis[i].tt_isdst)
1367 			if (++i >= sp->typecnt) {
1368 				i = 0;
1369 				break;
1370 			}
1371 	} else {
1372 		int	lo = 1;
1373 		int	hi = sp->timecnt;
1374 
1375 		while (lo < hi) {
1376 			int	mid = (lo + hi) / 2;
1377 
1378 			if (t < sp->ats[mid])
1379 				hi = mid;
1380 			else	lo = mid + 1;
1381 		}
1382 		i = (int) sp->types[lo - 1];
1383 	}
1384 	ttisp = &sp->ttis[i];
1385 	/*
1386 	** To get (wrong) behavior that's compatible with System V Release 2.0
1387 	** you'd replace the statement below with
1388 	**	t += ttisp->tt_gmtoff;
1389 	**	timesub(&t, 0L, sp, tmp);
1390 	*/
1391 	result = timesub(sp, &t, ttisp->tt_gmtoff, tmp);
1392 	tmp->tm_isdst = ttisp->tt_isdst;
1393 	if (sp == lclptr)
1394 		tzname[tmp->tm_isdst] = &sp->chars[ttisp->tt_abbrind];
1395 #ifdef TM_ZONE
1396 	tmp->TM_ZONE = &sp->chars[ttisp->tt_abbrind];
1397 #endif /* defined TM_ZONE */
1398 	return result;
1399 }
1400 
1401 /*
1402 ** Re-entrant version of localtime.
1403 */
1404 
1405 struct tm *
1406 localtime_r(const time_t * __restrict timep, struct tm *tmp)
1407 {
1408 	rwlock_rdlock(&lcl_lock);
1409 	tzset_unlocked();
1410 	tmp = localtime_rz(lclptr, timep, tmp);
1411 	rwlock_unlock(&lcl_lock);
1412 	return tmp;
1413 }
1414 
1415 struct tm *
1416 localtime(const time_t *const timep)
1417 {
1418 	return localtime_r(timep, &tm);
1419 }
1420 
1421 struct tm *
1422 localtime_rz(const timezone_t sp, const time_t * __restrict timep, struct tm *tmp)
1423 {
1424 	if (sp == NULL)
1425 		tmp = gmtsub(NULL, timep, 0L, tmp);
1426 	else
1427 		tmp = localsub(sp, timep, 0L, tmp);
1428 	if (tmp == NULL)
1429 		errno = EOVERFLOW;
1430 	return tmp;
1431 }
1432 
1433 /*
1434 ** gmtsub is to gmtime as localsub is to localtime.
1435 */
1436 
1437 static struct tm *
1438 gmtsub(const timezone_t sp, const time_t * const timep, const long offset,
1439     struct tm *const tmp)
1440 {
1441 	struct tm *	result;
1442 #ifdef _REENTRANT
1443 	static mutex_t gmt_mutex = MUTEX_INITIALIZER;
1444 #endif
1445 
1446 	mutex_lock(&gmt_mutex);
1447 	if (!gmt_is_set) {
1448 		int saveerrno;
1449 		gmt_is_set = TRUE;
1450 		saveerrno = errno;
1451 		gmtptr = calloc(1, sizeof *gmtptr);
1452 		errno = saveerrno;
1453 		if (gmtptr != NULL)
1454 			gmtload(gmtptr);
1455 	}
1456 	mutex_unlock(&gmt_mutex);
1457 	result = timesub(gmtptr, timep, offset, tmp);
1458 #ifdef TM_ZONE
1459 	/*
1460 	** Could get fancy here and deliver something such as
1461 	** "UTC+xxxx" or "UTC-xxxx" if offset is non-zero,
1462 	** but this is no time for a treasure hunt.
1463 	*/
1464 	if (offset != 0)
1465 		tmp->TM_ZONE = (__aconst char *)__UNCONST(wildabbr);
1466 	else {
1467 		if (gmtptr == NULL)
1468 			tmp->TM_ZONE = (__aconst char *)__UNCONST(gmt);
1469 		else	tmp->TM_ZONE = gmtptr->chars;
1470 	}
1471 #endif /* defined TM_ZONE */
1472 	return result;
1473 }
1474 
1475 struct tm *
1476 gmtime(const time_t *const timep)
1477 {
1478 	struct tm *tmp = gmtsub(NULL, timep, 0L, &tm);
1479 
1480 	if (tmp == NULL)
1481 		errno = EOVERFLOW;
1482 
1483 	return tmp;
1484 }
1485 
1486 /*
1487 ** Re-entrant version of gmtime.
1488 */
1489 
1490 struct tm *
1491 gmtime_r(const time_t * const timep, struct tm *tmp)
1492 {
1493 	tmp = gmtsub(NULL, timep, 0L, tmp);
1494 
1495 	if (tmp == NULL)
1496 		errno = EOVERFLOW;
1497 
1498 	return tmp;
1499 }
1500 
1501 #ifdef STD_INSPIRED
1502 
1503 struct tm *
1504 offtime(const time_t *const timep, long offset)
1505 {
1506 	struct tm *tmp = gmtsub(NULL, timep, offset, &tm);
1507 
1508 	if (tmp == NULL)
1509 		errno = EOVERFLOW;
1510 
1511 	return tmp;
1512 }
1513 
1514 struct tm *
1515 offtime_r(const time_t *timep, long offset, struct tm *tmp)
1516 {
1517 	tmp = gmtsub(NULL, timep, offset, tmp);
1518 
1519 	if (tmp == NULL)
1520 		errno = EOVERFLOW;
1521 
1522 	return tmp;
1523 }
1524 
1525 #endif /* defined STD_INSPIRED */
1526 
1527 /*
1528 ** Return the number of leap years through the end of the given year
1529 ** where, to make the math easy, the answer for year zero is defined as zero.
1530 */
1531 
1532 static int
1533 leaps_thru_end_of(const int y)
1534 {
1535 	return (y >= 0) ? (y / 4 - y / 100 + y / 400) :
1536 		-(leaps_thru_end_of(-(y + 1)) + 1);
1537 }
1538 
1539 static struct tm *
1540 timesub(const timezone_t sp, const time_t *const timep, const long offset,
1541     struct tm *const tmp)
1542 {
1543 	const struct lsinfo *	lp;
1544 	time_t			tdays;
1545 	int			idays;	/* unsigned would be so 2003 */
1546 	long			rem;
1547 	int			y;
1548 	const int *		ip;
1549 	long			corr;
1550 	int			hit;
1551 	int			i;
1552 
1553 	corr = 0;
1554 	hit = 0;
1555 	i = (sp == NULL) ? 0 : sp->leapcnt;
1556 	while (--i >= 0) {
1557 		lp = &sp->lsis[i];
1558 		if (*timep >= lp->ls_trans) {
1559 			if (*timep == lp->ls_trans) {
1560 				hit = ((i == 0 && lp->ls_corr > 0) ||
1561 					lp->ls_corr > sp->lsis[i - 1].ls_corr);
1562 				if (hit)
1563 					while (i > 0 &&
1564 						sp->lsis[i].ls_trans ==
1565 						sp->lsis[i - 1].ls_trans + 1 &&
1566 						sp->lsis[i].ls_corr ==
1567 						sp->lsis[i - 1].ls_corr + 1) {
1568 							++hit;
1569 							--i;
1570 					}
1571 			}
1572 			corr = lp->ls_corr;
1573 			break;
1574 		}
1575 	}
1576 	y = EPOCH_YEAR;
1577 	tdays = (time_t)(*timep / SECSPERDAY);
1578 	rem = (long) (*timep - tdays * SECSPERDAY);
1579 	while (tdays < 0 || tdays >= year_lengths[isleap(y)]) {
1580 		int		newy;
1581 		time_t	tdelta;
1582 		int	idelta;
1583 		int	leapdays;
1584 
1585 		tdelta = tdays / DAYSPERLYEAR;
1586 		idelta = (int) tdelta;
1587 		if (tdelta - idelta >= 1 || idelta - tdelta >= 1)
1588 			return NULL;
1589 		if (idelta == 0)
1590 			idelta = (tdays < 0) ? -1 : 1;
1591 		newy = y;
1592 		if (increment_overflow(&newy, idelta))
1593 			return NULL;
1594 		leapdays = leaps_thru_end_of(newy - 1) -
1595 			leaps_thru_end_of(y - 1);
1596 		tdays -= ((time_t) newy - y) * DAYSPERNYEAR;
1597 		tdays -= leapdays;
1598 		y = newy;
1599 	}
1600 	{
1601 		long	seconds;
1602 
1603 		seconds = tdays * SECSPERDAY + 0.5;
1604 		tdays = (time_t)(seconds / SECSPERDAY);
1605 		rem += (long) (seconds - tdays * SECSPERDAY);
1606 	}
1607 	/*
1608 	** Given the range, we can now fearlessly cast...
1609 	*/
1610 	idays = (int) tdays;
1611 	rem += offset - corr;
1612 	while (rem < 0) {
1613 		rem += SECSPERDAY;
1614 		--idays;
1615 	}
1616 	while (rem >= SECSPERDAY) {
1617 		rem -= SECSPERDAY;
1618 		++idays;
1619 	}
1620 	while (idays < 0) {
1621 		if (increment_overflow(&y, -1))
1622 			return NULL;
1623 		idays += year_lengths[isleap(y)];
1624 	}
1625 	while (idays >= year_lengths[isleap(y)]) {
1626 		idays -= year_lengths[isleap(y)];
1627 		if (increment_overflow(&y, 1))
1628 			return NULL;
1629 	}
1630 	tmp->tm_year = y;
1631 	if (increment_overflow(&tmp->tm_year, -TM_YEAR_BASE))
1632 		return NULL;
1633 	tmp->tm_yday = idays;
1634 	/*
1635 	** The "extra" mods below avoid overflow problems.
1636 	*/
1637 	tmp->tm_wday = EPOCH_WDAY +
1638 		((y - EPOCH_YEAR) % DAYSPERWEEK) *
1639 		(DAYSPERNYEAR % DAYSPERWEEK) +
1640 		leaps_thru_end_of(y - 1) -
1641 		leaps_thru_end_of(EPOCH_YEAR - 1) +
1642 		idays;
1643 	tmp->tm_wday %= DAYSPERWEEK;
1644 	if (tmp->tm_wday < 0)
1645 		tmp->tm_wday += DAYSPERWEEK;
1646 	tmp->tm_hour = (int) (rem / SECSPERHOUR);
1647 	rem %= SECSPERHOUR;
1648 	tmp->tm_min = (int) (rem / SECSPERMIN);
1649 	/*
1650 	** A positive leap second requires a special
1651 	** representation. This uses "... ??:59:60" et seq.
1652 	*/
1653 	tmp->tm_sec = (int) (rem % SECSPERMIN) + hit;
1654 	ip = mon_lengths[isleap(y)];
1655 	for (tmp->tm_mon = 0; idays >= ip[tmp->tm_mon]; ++(tmp->tm_mon))
1656 		idays -= ip[tmp->tm_mon];
1657 	tmp->tm_mday = (int) (idays + 1);
1658 	tmp->tm_isdst = 0;
1659 #ifdef TM_GMTOFF
1660 	tmp->TM_GMTOFF = offset;
1661 #endif /* defined TM_GMTOFF */
1662 	return tmp;
1663 }
1664 
1665 char *
1666 ctime(const time_t *const timep)
1667 {
1668 /*
1669 ** Section 4.12.3.2 of X3.159-1989 requires that
1670 **	The ctime function converts the calendar time pointed to by timer
1671 **	to local time in the form of a string. It is equivalent to
1672 **		asctime(localtime(timer))
1673 */
1674 	struct tm *rtm = localtime(timep);
1675 	if (rtm == NULL)
1676 		return NULL;
1677 	return asctime(rtm);
1678 }
1679 
1680 char *
1681 ctime_r(const time_t *const timep, char *buf)
1682 {
1683 	struct tm	mytm, *rtm;
1684 
1685 	rtm = localtime_r(timep, &mytm);
1686 	if (rtm == NULL)
1687 		return NULL;
1688 	return asctime_r(rtm, buf);
1689 }
1690 
1691 char *
1692 ctime_rz(const timezone_t sp, const time_t * timep, char *buf)
1693 {
1694 	struct tm	mytm, *rtm;
1695 
1696 	rtm = localtime_rz(sp, timep, &mytm);
1697 	if (rtm == NULL)
1698 		return NULL;
1699 	return asctime_r(rtm, buf);
1700 }
1701 
1702 /*
1703 ** Adapted from code provided by Robert Elz, who writes:
1704 **	The "best" way to do mktime I think is based on an idea of Bob
1705 **	Kridle's (so its said...) from a long time ago.
1706 **	It does a binary search of the time_t space. Since time_t's are
1707 **	just 32 bits, its a max of 32 iterations (even at 64 bits it
1708 **	would still be very reasonable).
1709 */
1710 
1711 #ifndef WRONG
1712 #define WRONG	((time_t)-1)
1713 #endif /* !defined WRONG */
1714 
1715 /*
1716 ** Simplified normalize logic courtesy Paul Eggert.
1717 */
1718 
1719 static int
1720 increment_overflow(int *ip, int j)
1721 {
1722 	int	i = *ip;
1723 
1724 	/*
1725 	** If i >= 0 there can only be overflow if i + j > INT_MAX
1726 	** or if j > INT_MAX - i; given i >= 0, INT_MAX - i cannot overflow.
1727 	** If i < 0 there can only be overflow if i + j < INT_MIN
1728 	** or if j < INT_MIN - i; given i < 0, INT_MIN - i cannot overflow.
1729 	*/
1730 	if ((i >= 0) ? (j > INT_MAX - i) : (j < INT_MIN - i))
1731 		return TRUE;
1732 	*ip += j;
1733 	return FALSE;
1734 }
1735 
1736 static int
1737 long_increment_overflow(long *lp, int m)
1738 {
1739 	long l = *lp;
1740 
1741 	if ((l >= 0) ? (m > LONG_MAX - l) : (m < LONG_MIN - l))
1742 		return TRUE;
1743 	*lp += m;
1744 	return FALSE;
1745 }
1746 
1747 static int
1748 normalize_overflow(int *const tensptr, int *const unitsptr, const int base)
1749 {
1750 	int	tensdelta;
1751 
1752 	tensdelta = (*unitsptr >= 0) ?
1753 		(*unitsptr / base) :
1754 		(-1 - (-1 - *unitsptr) / base);
1755 	*unitsptr -= tensdelta * base;
1756 	return increment_overflow(tensptr, tensdelta);
1757 }
1758 
1759 static int
1760 long_normalize_overflow(long *const tensptr, int *const unitsptr,
1761     const int base)
1762 {
1763 	int	tensdelta;
1764 
1765 	tensdelta = (*unitsptr >= 0) ?
1766 		(*unitsptr / base) :
1767 		(-1 - (-1 - *unitsptr) / base);
1768 	*unitsptr -= tensdelta * base;
1769 	return long_increment_overflow(tensptr, tensdelta);
1770 }
1771 
1772 static int
1773 tmcomp(const struct tm *const atmp, const struct tm *const btmp)
1774 {
1775 	int	result;
1776 
1777 	if ((result = (atmp->tm_year - btmp->tm_year)) == 0 &&
1778 		(result = (atmp->tm_mon - btmp->tm_mon)) == 0 &&
1779 		(result = (atmp->tm_mday - btmp->tm_mday)) == 0 &&
1780 		(result = (atmp->tm_hour - btmp->tm_hour)) == 0 &&
1781 		(result = (atmp->tm_min - btmp->tm_min)) == 0)
1782 			result = atmp->tm_sec - btmp->tm_sec;
1783 	return result;
1784 }
1785 
1786 static time_t
1787 time2sub(const timezone_t sp, struct tm *const tmp, subfun_t funcp,
1788     const long offset, int *const okayp, const int do_norm_secs)
1789 {
1790 	int			dir;
1791 	int			i, j;
1792 	int			saved_seconds;
1793 	long			li;
1794 	time_t			lo;
1795 	time_t			hi;
1796 #ifdef NO_ERROR_IN_DST_GAP
1797 	time_t			ilo;
1798 #endif
1799 	long				y;
1800 	time_t				newt;
1801 	time_t				t;
1802 	struct tm			yourtm, mytm;
1803 
1804 	*okayp = FALSE;
1805 	yourtm = *tmp;
1806 #ifdef NO_ERROR_IN_DST_GAP
1807 again:
1808 #endif
1809 	if (do_norm_secs) {
1810 		if (normalize_overflow(&yourtm.tm_min, &yourtm.tm_sec,
1811 		    SECSPERMIN))
1812 			goto overflow;
1813 	}
1814 	if (normalize_overflow(&yourtm.tm_hour, &yourtm.tm_min, MINSPERHOUR))
1815 		goto overflow;
1816 	if (normalize_overflow(&yourtm.tm_mday, &yourtm.tm_hour, HOURSPERDAY))
1817 		goto overflow;
1818 	y = yourtm.tm_year;
1819 	if (long_normalize_overflow(&y, &yourtm.tm_mon, MONSPERYEAR))
1820 		goto overflow;
1821 	/*
1822 	** Turn y into an actual year number for now.
1823 	** It is converted back to an offset from TM_YEAR_BASE later.
1824 	*/
1825 	if (long_increment_overflow(&y, TM_YEAR_BASE))
1826 		goto overflow;
1827 	while (yourtm.tm_mday <= 0) {
1828 		if (long_increment_overflow(&y, -1))
1829 			goto overflow;
1830 		li = y + (1 < yourtm.tm_mon);
1831 		yourtm.tm_mday += year_lengths[isleap(li)];
1832 	}
1833 	while (yourtm.tm_mday > DAYSPERLYEAR) {
1834 		li = y + (1 < yourtm.tm_mon);
1835 		yourtm.tm_mday -= year_lengths[isleap(li)];
1836 		if (long_increment_overflow(&y, 1))
1837 			goto overflow;
1838 	}
1839 	for ( ; ; ) {
1840 		i = mon_lengths[isleap(y)][yourtm.tm_mon];
1841 		if (yourtm.tm_mday <= i)
1842 			break;
1843 		yourtm.tm_mday -= i;
1844 		if (++yourtm.tm_mon >= MONSPERYEAR) {
1845 			yourtm.tm_mon = 0;
1846 			if (long_increment_overflow(&y, 1))
1847 				goto overflow;
1848 		}
1849 	}
1850 	if (long_increment_overflow(&y, -TM_YEAR_BASE))
1851 		goto overflow;
1852 	yourtm.tm_year = (int)y;
1853 	if (yourtm.tm_year != y)
1854 		goto overflow;
1855 	if (yourtm.tm_sec >= 0 && yourtm.tm_sec < SECSPERMIN)
1856 		saved_seconds = 0;
1857 	else if (y + TM_YEAR_BASE < EPOCH_YEAR) {
1858 		/*
1859 		** We can't set tm_sec to 0, because that might push the
1860 		** time below the minimum representable time.
1861 		** Set tm_sec to 59 instead.
1862 		** This assumes that the minimum representable time is
1863 		** not in the same minute that a leap second was deleted from,
1864 		** which is a safer assumption than using 58 would be.
1865 		*/
1866 		if (increment_overflow(&yourtm.tm_sec, 1 - SECSPERMIN))
1867 			goto overflow;
1868 		saved_seconds = yourtm.tm_sec;
1869 		yourtm.tm_sec = SECSPERMIN - 1;
1870 	} else {
1871 		saved_seconds = yourtm.tm_sec;
1872 		yourtm.tm_sec = 0;
1873 	}
1874 	/*
1875 	** Do a binary search (this works whatever time_t's type is).
1876 	*/
1877 /* LINTED constant */
1878 	if (!TYPE_SIGNED(time_t)) {
1879 		lo = 0;
1880 		hi = lo - 1;
1881 /* LINTED constant */
1882 	} else if (!TYPE_INTEGRAL(time_t)) {
1883 /* CONSTCOND */
1884 		if (sizeof(time_t) > sizeof(float))
1885 /* LINTED assumed double */
1886 			hi = (time_t) DBL_MAX;
1887 /* LINTED assumed float */
1888 		else	hi = (time_t) FLT_MAX;
1889 		lo = -hi;
1890 	} else {
1891 		lo = 1;
1892 		for (i = 0; i < (int) TYPE_BIT(time_t) - 1; ++i)
1893 			lo *= 2;
1894 		hi = -(lo + 1);
1895 	}
1896 #ifdef NO_ERROR_IN_DST_GAP
1897 	ilo = lo;
1898 #endif
1899 	for ( ; ; ) {
1900 		t = lo / 2 + hi / 2;
1901 		if (t < lo)
1902 			t = lo;
1903 		else if (t > hi)
1904 			t = hi;
1905 		if ((*funcp)(sp, &t, offset, &mytm) == NULL) {
1906 			/*
1907 			** Assume that t is too extreme to be represented in
1908 			** a struct tm; arrange things so that it is less
1909 			** extreme on the next pass.
1910 			*/
1911 			dir = (t > 0) ? 1 : -1;
1912 		} else	dir = tmcomp(&mytm, &yourtm);
1913 		if (dir != 0) {
1914 			if (t == lo) {
1915 				++t;
1916 				if (t <= lo)
1917 					goto overflow;
1918 				++lo;
1919 			} else if (t == hi) {
1920 				--t;
1921 				if (t >= hi)
1922 					goto overflow;
1923 				--hi;
1924 			}
1925 #ifdef NO_ERROR_IN_DST_GAP
1926 			if (ilo != lo && lo - 1 == hi && yourtm.tm_isdst < 0 &&
1927 			    do_norm_secs) {
1928 				for (i = sp->typecnt - 1; i >= 0; --i) {
1929 					for (j = sp->typecnt - 1; j >= 0; --j) {
1930 						time_t off;
1931 						if (sp->ttis[j].tt_isdst ==
1932 						    sp->ttis[i].tt_isdst)
1933 							continue;
1934 						off = sp->ttis[j].tt_gmtoff -
1935 						    sp->ttis[i].tt_gmtoff;
1936 						yourtm.tm_sec += off < 0 ?
1937 						    -off : off;
1938 						goto again;
1939 					}
1940 				}
1941 			}
1942 #endif
1943 			if (lo > hi)
1944 				goto invalid;
1945 			if (dir > 0)
1946 				hi = t;
1947 			else	lo = t;
1948 			continue;
1949 		}
1950 		if (yourtm.tm_isdst < 0 || mytm.tm_isdst == yourtm.tm_isdst)
1951 			break;
1952 		/*
1953 		** Right time, wrong type.
1954 		** Hunt for right time, right type.
1955 		** It's okay to guess wrong since the guess
1956 		** gets checked.
1957 		*/
1958 		if (sp == NULL)
1959 			goto invalid;
1960 		for (i = sp->typecnt - 1; i >= 0; --i) {
1961 			if (sp->ttis[i].tt_isdst != yourtm.tm_isdst)
1962 				continue;
1963 			for (j = sp->typecnt - 1; j >= 0; --j) {
1964 				if (sp->ttis[j].tt_isdst == yourtm.tm_isdst)
1965 					continue;
1966 				newt = (time_t)(t + sp->ttis[j].tt_gmtoff -
1967 				    sp->ttis[i].tt_gmtoff);
1968 				if ((*funcp)(sp, &newt, offset, &mytm) == NULL)
1969 					continue;
1970 				if (tmcomp(&mytm, &yourtm) != 0)
1971 					continue;
1972 				if (mytm.tm_isdst != yourtm.tm_isdst)
1973 					continue;
1974 				/*
1975 				** We have a match.
1976 				*/
1977 				t = newt;
1978 				goto label;
1979 			}
1980 		}
1981 		goto invalid;
1982 	}
1983 label:
1984 	newt = t + saved_seconds;
1985 	if ((newt < t) != (saved_seconds < 0))
1986 		goto overflow;
1987 	t = newt;
1988 	if ((*funcp)(sp, &t, offset, tmp)) {
1989 		*okayp = TRUE;
1990 		return t;
1991 	}
1992 overflow:
1993 	errno = EOVERFLOW;
1994 	return WRONG;
1995 invalid:
1996 	errno = EINVAL;
1997 	return WRONG;
1998 }
1999 
2000 static time_t
2001 time2(const timezone_t sp, struct tm *const tmp, subfun_t funcp,
2002     const long offset, int *const okayp)
2003 {
2004 	time_t	t;
2005 
2006 	/*
2007 	** First try without normalization of seconds
2008 	** (in case tm_sec contains a value associated with a leap second).
2009 	** If that fails, try with normalization of seconds.
2010 	*/
2011 	t = time2sub(sp, tmp, funcp, offset, okayp, FALSE);
2012 	return *okayp ? t : time2sub(sp, tmp, funcp, offset, okayp, TRUE);
2013 }
2014 
2015 static time_t
2016 time1(const timezone_t sp, struct tm *const tmp, subfun_t funcp,
2017     long offset)
2018 {
2019 	time_t			t;
2020 	int			samei, otheri;
2021 	int			sameind, otherind;
2022 	int			i;
2023 	int			nseen;
2024 	int				seen[TZ_MAX_TYPES];
2025 	int				types[TZ_MAX_TYPES];
2026 	int				okay;
2027 
2028 	if (tmp == NULL) {
2029 		errno = EINVAL;
2030 		return WRONG;
2031 	}
2032 	if (tmp->tm_isdst > 1)
2033 		tmp->tm_isdst = 1;
2034 	t = time2(sp, tmp, funcp, offset, &okay);
2035 #ifdef PCTS
2036 	/*
2037 	** PCTS code courtesy Grant Sullivan.
2038 	*/
2039 	if (okay)
2040 		return t;
2041 	if (tmp->tm_isdst < 0)
2042 		tmp->tm_isdst = 0;	/* reset to std and try again */
2043 #endif /* defined PCTS */
2044 #ifndef PCTS
2045 	if (okay || tmp->tm_isdst < 0)
2046 		return t;
2047 #endif /* !defined PCTS */
2048 	/*
2049 	** We're supposed to assume that somebody took a time of one type
2050 	** and did some math on it that yielded a "struct tm" that's bad.
2051 	** We try to divine the type they started from and adjust to the
2052 	** type they need.
2053 	*/
2054 	if (sp == NULL) {
2055 		errno = EINVAL;
2056 		return WRONG;
2057 	}
2058 	for (i = 0; i < sp->typecnt; ++i)
2059 		seen[i] = FALSE;
2060 	nseen = 0;
2061 	for (i = sp->timecnt - 1; i >= 0; --i)
2062 		if (!seen[sp->types[i]]) {
2063 			seen[sp->types[i]] = TRUE;
2064 			types[nseen++] = sp->types[i];
2065 		}
2066 	for (sameind = 0; sameind < nseen; ++sameind) {
2067 		samei = types[sameind];
2068 		if (sp->ttis[samei].tt_isdst != tmp->tm_isdst)
2069 			continue;
2070 		for (otherind = 0; otherind < nseen; ++otherind) {
2071 			otheri = types[otherind];
2072 			if (sp->ttis[otheri].tt_isdst == tmp->tm_isdst)
2073 				continue;
2074 			tmp->tm_sec += (int)(sp->ttis[otheri].tt_gmtoff -
2075 					sp->ttis[samei].tt_gmtoff);
2076 			tmp->tm_isdst = !tmp->tm_isdst;
2077 			t = time2(sp, tmp, funcp, offset, &okay);
2078 			if (okay)
2079 				return t;
2080 			tmp->tm_sec -= (int)(sp->ttis[otheri].tt_gmtoff -
2081 					sp->ttis[samei].tt_gmtoff);
2082 			tmp->tm_isdst = !tmp->tm_isdst;
2083 		}
2084 	}
2085 	errno = EOVERFLOW;
2086 	return WRONG;
2087 }
2088 
2089 time_t
2090 mktime_z(const timezone_t sp, struct tm *tmp)
2091 {
2092 	time_t t;
2093 	if (sp == NULL)
2094 		t = time1(NULL, tmp, gmtsub, 0L);
2095 	else
2096 		t = time1(sp, tmp, localsub, 0L);
2097 	return t;
2098 }
2099 
2100 time_t
2101 mktime(struct tm * const	tmp)
2102 {
2103 	time_t result;
2104 
2105 	rwlock_wrlock(&lcl_lock);
2106 	tzset_unlocked();
2107 	result = mktime_z(lclptr, tmp);
2108 	rwlock_unlock(&lcl_lock);
2109 	return result;
2110 }
2111 
2112 #ifdef STD_INSPIRED
2113 
2114 time_t
2115 timelocal_z(const timezone_t sp, struct tm *tmp)
2116 {
2117 	if (tmp != NULL)
2118 		tmp->tm_isdst = -1;	/* in case it wasn't initialized */
2119 	return mktime_z(sp, tmp);
2120 }
2121 
2122 time_t
2123 timelocal(struct tm *const tmp)
2124 {
2125 	if (tmp != NULL)
2126 		tmp->tm_isdst = -1;	/* in case it wasn't initialized */
2127 	return mktime(tmp);
2128 }
2129 
2130 time_t
2131 timegm(struct tm *const tmp)
2132 {
2133 	time_t t;
2134 
2135 	if (tmp != NULL)
2136 		tmp->tm_isdst = 0;
2137 	t = time1(gmtptr, tmp, gmtsub, 0L);
2138 	return t;
2139 }
2140 
2141 time_t
2142 timeoff(struct tm *const tmp, const long offset)
2143 {
2144 	time_t t;
2145 
2146 	if (tmp != NULL)
2147 		tmp->tm_isdst = 0;
2148 	t = time1(gmtptr, tmp, gmtsub, offset);
2149 	return t;
2150 }
2151 
2152 #endif /* defined STD_INSPIRED */
2153 
2154 #ifdef CMUCS
2155 
2156 /*
2157 ** The following is supplied for compatibility with
2158 ** previous versions of the CMUCS runtime library.
2159 */
2160 
2161 long
2162 gtime(struct tm *const tmp)
2163 {
2164 	const time_t t = mktime(tmp);
2165 
2166 	if (t == WRONG)
2167 		return -1;
2168 	return t;
2169 }
2170 
2171 #endif /* defined CMUCS */
2172 
2173 /*
2174 ** XXX--is the below the right way to conditionalize??
2175 */
2176 
2177 #ifdef STD_INSPIRED
2178 
2179 /*
2180 ** IEEE Std 1003.1-1988 (POSIX) legislates that 536457599
2181 ** shall correspond to "Wed Dec 31 23:59:59 UTC 1986", which
2182 ** is not the case if we are accounting for leap seconds.
2183 ** So, we provide the following conversion routines for use
2184 ** when exchanging timestamps with POSIX conforming systems.
2185 */
2186 
2187 static long
2188 leapcorr(const timezone_t sp, time_t *timep)
2189 {
2190 	struct lsinfo * lp;
2191 	int		i;
2192 
2193 	i = sp->leapcnt;
2194 	while (--i >= 0) {
2195 		lp = &sp->lsis[i];
2196 		if (*timep >= lp->ls_trans)
2197 			return lp->ls_corr;
2198 	}
2199 	return 0;
2200 }
2201 
2202 time_t
2203 time2posix_z(const timezone_t sp, time_t t)
2204 {
2205 	return (time_t)(t - leapcorr(sp, &t));
2206 }
2207 
2208 time_t
2209 time2posix(time_t t)
2210 {
2211 	time_t result;
2212 	rwlock_wrlock(&lcl_lock);
2213 	tzset_unlocked();
2214 	result = (time_t)(t - leapcorr(lclptr, &t));
2215 	rwlock_unlock(&lcl_lock);
2216 	return (result);
2217 }
2218 
2219 time_t
2220 posix2time_z(const timezone_t sp, time_t t)
2221 {
2222 	time_t	x;
2223 	time_t	y;
2224 
2225 	/*
2226 	** For a positive leap second hit, the result
2227 	** is not unique. For a negative leap second
2228 	** hit, the corresponding time doesn't exist,
2229 	** so we return an adjacent second.
2230 	*/
2231 	x = (time_t)(t + leapcorr(sp, &t));
2232 	y = (time_t)(x - leapcorr(sp, &x));
2233 	if (y < t) {
2234 		do {
2235 			x++;
2236 			y = (time_t)(x - leapcorr(sp, &x));
2237 		} while (y < t);
2238 		if (t != y) {
2239 			return x - 1;
2240 		}
2241 	} else if (y > t) {
2242 		do {
2243 			--x;
2244 			y = (time_t)(x - leapcorr(sp, &x));
2245 		} while (y > t);
2246 		if (t != y) {
2247 			return x + 1;
2248 		}
2249 	}
2250 	return x;
2251 }
2252 
2253 
2254 
2255 time_t
2256 posix2time(time_t t)
2257 {
2258 	time_t result;
2259 
2260 	rwlock_wrlock(&lcl_lock);
2261 	tzset_unlocked();
2262 	result = posix2time_z(lclptr, t);
2263 	rwlock_unlock(&lcl_lock);
2264 	return result;
2265 }
2266 
2267 #endif /* defined STD_INSPIRED */
2268