xref: /netbsd-src/lib/libc/time/localtime.c (revision 481fca6e59249d8ffcf24fef7cfbe7b131bfb080)
1 /*	$NetBSD: localtime.c,v 1.23 2000/01/22 22:19:21 mycroft Exp $	*/
2 
3 /*
4 ** This file is in the public domain, so clarified as of
5 ** 1996-06-05 by Arthur David Olson (arthur_david_olson@nih.gov).
6 */
7 
8 #include <sys/cdefs.h>
9 #ifndef lint
10 #ifndef NOID
11 #if 0
12 static char	elsieid[] = "@(#)localtime.c	7.70";
13 #else
14 __RCSID("$NetBSD: localtime.c,v 1.23 2000/01/22 22:19:21 mycroft Exp $");
15 #endif
16 #endif /* !defined NOID */
17 #endif /* !defined lint */
18 
19 /*
20 ** Leap second handling from Bradley White (bww@k.gp.cs.cmu.edu).
21 ** POSIX-style TZ environment variable handling from Guy Harris
22 ** (guy@auspex.com).
23 */
24 
25 /*LINTLIBRARY*/
26 
27 #include "namespace.h"
28 #include "private.h"
29 #include "tzfile.h"
30 #include "fcntl.h"
31 #include "reentrant.h"
32 
33 #ifdef __weak_alias
34 __weak_alias(ctime_r,_ctime_r)
35 __weak_alias(gmtime_r,_gmtime_r)
36 __weak_alias(localtime_r,_localtime_r)
37 __weak_alias(offtime,_offtime)
38 __weak_alias(posix2time,_posix2time)
39 __weak_alias(time2posix,_time2posix)
40 __weak_alias(timegm,_timegm)
41 __weak_alias(timelocal,_timelocal)
42 __weak_alias(timeoff,_timeoff)
43 __weak_alias(tzname,_tzname)
44 __weak_alias(tzset,_tzset)
45 __weak_alias(tzsetwall,_tzsetwall)
46 #endif
47 
48 /*
49 ** SunOS 4.1.1 headers lack O_BINARY.
50 */
51 
52 #ifdef O_BINARY
53 #define OPEN_MODE	(O_RDONLY | O_BINARY)
54 #endif /* defined O_BINARY */
55 #ifndef O_BINARY
56 #define OPEN_MODE	O_RDONLY
57 #endif /* !defined O_BINARY */
58 
59 #ifndef WILDABBR
60 /*
61 ** Someone might make incorrect use of a time zone abbreviation:
62 **	1.	They might reference tzname[0] before calling tzset (explicitly
63 **		or implicitly).
64 **	2.	They might reference tzname[1] before calling tzset (explicitly
65 **		or implicitly).
66 **	3.	They might reference tzname[1] after setting to a time zone
67 **		in which Daylight Saving Time is never observed.
68 **	4.	They might reference tzname[0] after setting to a time zone
69 **		in which Standard Time is never observed.
70 **	5.	They might reference tm.TM_ZONE after calling offtime.
71 ** What's best to do in the above cases is open to debate;
72 ** for now, we just set things up so that in any of the five cases
73 ** WILDABBR is used.  Another possibility:  initialize tzname[0] to the
74 ** string "tzname[0] used before set", and similarly for the other cases.
75 ** And another:  initialize tzname[0] to "ERA", with an explanation in the
76 ** manual page of what this "time zone abbreviation" means (doing this so
77 ** that tzname[0] has the "normal" length of three characters).
78 */
79 #define WILDABBR	"   "
80 #endif /* !defined WILDABBR */
81 
82 static const char	wildabbr[] = "WILDABBR";
83 
84 static const char	gmt[] = "GMT";
85 
86 /*
87 ** The DST rules to use if TZ has no rules and we can't load TZDEFRULES.
88 ** We default to US rules as of 1999-08-17.
89 ** POSIX 1003.1 section 8.1.1 says that the default DST rules are
90 ** implementation dependent; for historical reasons, US rules are a
91 ** common default.
92 */
93 #ifndef TZDEFRULESTRING
94 #define TZDEFRULESTRING ",M4.1.0,M10.5.0"
95 #endif /* !defined TZDEFDST */
96 
97 struct ttinfo {				/* time type information */
98 	long		tt_gmtoff;	/* UTC offset in seconds */
99 	int		tt_isdst;	/* used to set tm_isdst */
100 	int		tt_abbrind;	/* abbreviation list index */
101 	int		tt_ttisstd;	/* TRUE if transition is std time */
102 	int		tt_ttisgmt;	/* TRUE if transition is UTC */
103 };
104 
105 struct lsinfo {				/* leap second information */
106 	time_t		ls_trans;	/* transition time */
107 	long		ls_corr;	/* correction to apply */
108 };
109 
110 #define BIGGEST(a, b)	(((a) > (b)) ? (a) : (b))
111 
112 #ifdef TZNAME_MAX
113 #define MY_TZNAME_MAX	TZNAME_MAX
114 #endif /* defined TZNAME_MAX */
115 #ifndef TZNAME_MAX
116 #define MY_TZNAME_MAX	255
117 #endif /* !defined TZNAME_MAX */
118 
119 struct state {
120 	int		leapcnt;
121 	int		timecnt;
122 	int		typecnt;
123 	int		charcnt;
124 	time_t		ats[TZ_MAX_TIMES];
125 	unsigned char	types[TZ_MAX_TIMES];
126 	struct ttinfo	ttis[TZ_MAX_TYPES];
127 	char		chars[/* LINTED constant */BIGGEST(BIGGEST(TZ_MAX_CHARS + 1, sizeof gmt),
128 				(2 * (MY_TZNAME_MAX + 1)))];
129 	struct lsinfo	lsis[TZ_MAX_LEAPS];
130 };
131 
132 struct rule {
133 	int		r_type;		/* type of rule--see below */
134 	int		r_day;		/* day number of rule */
135 	int		r_week;		/* week number of rule */
136 	int		r_mon;		/* month number of rule */
137 	long		r_time;		/* transition time of rule */
138 };
139 
140 #define JULIAN_DAY		0	/* Jn - Julian day */
141 #define DAY_OF_YEAR		1	/* n - day of year */
142 #define MONTH_NTH_DAY_OF_WEEK	2	/* Mm.n.d - month, week, day of week */
143 
144 /*
145 ** Prototypes for static functions.
146 */
147 
148 static long		detzcode P((const char * codep));
149 static const char *	getzname P((const char * strp));
150 static const char *	getnum P((const char * strp, int * nump, int min,
151 				int max));
152 static const char *	getsecs P((const char * strp, long * secsp));
153 static const char *	getoffset P((const char * strp, long * offsetp));
154 static const char *	getrule P((const char * strp, struct rule * rulep));
155 static void		gmtload P((struct state * sp));
156 static void		gmtsub P((const time_t * timep, long offset,
157 				struct tm * tmp));
158 static void		localsub P((const time_t * timep, long offset,
159 				struct tm * tmp));
160 static int		increment_overflow P((int * number, int delta));
161 static int		normalize_overflow P((int * tensptr, int * unitsptr,
162 				int base));
163 static void		settzname P((void));
164 static time_t		time1 P((struct tm * tmp,
165 				void(*funcp) P((const time_t *,
166 				long, struct tm *)),
167 				long offset));
168 static time_t		time2 P((struct tm *tmp,
169 				void(*funcp) P((const time_t *,
170 				long, struct tm*)),
171 				long offset, int * okayp));
172 static time_t		time2sub P((struct tm *tmp,
173 				void(*funcp) P((const time_t *,
174 				long, struct tm*)),
175 				long offset, int * okayp, int do_norm_secs));
176 static void		timesub P((const time_t * timep, long offset,
177 				const struct state * sp, struct tm * tmp));
178 static int		tmcomp P((const struct tm * atmp,
179 				const struct tm * btmp));
180 static time_t		transtime P((time_t janfirst, int year,
181 				const struct rule * rulep, long offset));
182 static int		tzload P((const char * name, struct state * sp));
183 static int		tzparse P((const char * name, struct state * sp,
184 				int lastditch));
185 static void		tzset_unlocked P((void));
186 static void		tzsetwall_unlocked P((void));
187 #ifdef STD_INSPIRED
188 static long		leapcorr P((time_t * timep));
189 #endif
190 
191 #ifdef ALL_STATE
192 static struct state *	lclptr;
193 static struct state *	gmtptr;
194 #endif /* defined ALL_STATE */
195 
196 #ifndef ALL_STATE
197 static struct state	lclmem;
198 static struct state	gmtmem;
199 #define lclptr		(&lclmem)
200 #define gmtptr		(&gmtmem)
201 #endif /* State Farm */
202 
203 #ifndef TZ_STRLEN_MAX
204 #define TZ_STRLEN_MAX 255
205 #endif /* !defined TZ_STRLEN_MAX */
206 
207 static char		lcl_TZname[TZ_STRLEN_MAX + 1];
208 static int		lcl_is_set;
209 static int		gmt_is_set;
210 
211 __aconst char *		tzname[2] = {
212 	/* LINTED const castaway */
213 	(__aconst char *)wildabbr,
214 	/* LINTED const castaway */
215 	(__aconst char *)wildabbr
216 };
217 
218 #ifdef _REENT
219 static rwlock_t lcl_lock = RWLOCK_INITIALIZER;
220 #endif
221 
222 /*
223 ** Section 4.12.3 of X3.159-1989 requires that
224 **	Except for the strftime function, these functions [asctime,
225 **	ctime, gmtime, localtime] return values in one of two static
226 **	objects: a broken-down time structure and an array of char.
227 ** Thanks to Paul Eggert (eggert@twinsun.com) for noting this.
228 */
229 
230 static struct tm	tm;
231 
232 #ifdef USG_COMPAT
233 time_t			timezone = 0;
234 int			daylight = 0;
235 #endif /* defined USG_COMPAT */
236 
237 #ifdef ALTZONE
238 time_t			altzone = 0;
239 #endif /* defined ALTZONE */
240 
241 static long
242 detzcode(codep)
243 const char * const	codep;
244 {
245 	register long	result;
246 
247 	/*
248         ** The first character must be sign extended on systems with >32bit
249         ** longs.  This was solved differently in the master tzcode sources
250         ** (the fix first appeared in tzcode95c.tar.gz).  But I believe
251 	** that this implementation is superior.
252         */
253 
254 #ifdef __STDC__
255 #define SIGN_EXTEND_CHAR(x)	((signed char) x)
256 #else
257 #define SIGN_EXTEND_CHAR(x)	((x & 0x80) ? ((~0 << 8) | x) : x)
258 #endif
259 
260 	result = (SIGN_EXTEND_CHAR(codep[0]) << 24) \
261 	       | (codep[1] & 0xff) << 16 \
262 	       | (codep[2] & 0xff) << 8
263 	       | (codep[3] & 0xff);
264 	return result;
265 }
266 
267 static void
268 settzname P((void))
269 {
270 	register struct state * const	sp = lclptr;
271 	register int			i;
272 
273 	/* LINTED const castaway */
274 	tzname[0] = (__aconst char *)wildabbr;
275 	/* LINTED const castaway */
276 	tzname[1] = (__aconst char *)wildabbr;
277 #ifdef USG_COMPAT
278 	daylight = 0;
279 	timezone = 0;
280 #endif /* defined USG_COMPAT */
281 #ifdef ALTZONE
282 	altzone = 0;
283 #endif /* defined ALTZONE */
284 #ifdef ALL_STATE
285 	if (sp == NULL) {
286 		tzname[0] = tzname[1] = (__aconst char *)gmt;
287 		return;
288 	}
289 #endif /* defined ALL_STATE */
290 	for (i = 0; i < sp->typecnt; ++i) {
291 		register const struct ttinfo * const	ttisp = &sp->ttis[i];
292 
293 		tzname[ttisp->tt_isdst] =
294 			&sp->chars[ttisp->tt_abbrind];
295 #ifdef USG_COMPAT
296 		if (ttisp->tt_isdst)
297 			daylight = 1;
298 		if (i == 0 || !ttisp->tt_isdst)
299 			timezone = -(ttisp->tt_gmtoff);
300 #endif /* defined USG_COMPAT */
301 #ifdef ALTZONE
302 		if (i == 0 || ttisp->tt_isdst)
303 			altzone = -(ttisp->tt_gmtoff);
304 #endif /* defined ALTZONE */
305 	}
306 	/*
307 	** And to get the latest zone names into tzname. . .
308 	*/
309 	for (i = 0; i < sp->timecnt; ++i) {
310 		register const struct ttinfo * const	ttisp =
311 							&sp->ttis[
312 								sp->types[i]];
313 
314 		tzname[ttisp->tt_isdst] =
315 			&sp->chars[ttisp->tt_abbrind];
316 	}
317 }
318 
319 static int
320 tzload(name, sp)
321 register const char *		name;
322 register struct state * const	sp;
323 {
324 	register const char *	p;
325 	register int		i;
326 	register int		fid;
327 
328 	if (name == NULL && (name = TZDEFAULT) == NULL)
329 		return -1;
330 
331 	{
332 		register int	doaccess;
333 		/*
334 		** Section 4.9.1 of the C standard says that
335 		** "FILENAME_MAX expands to an integral constant expression
336 		** that is the size needed for an array of char large enough
337 		** to hold the longest file name string that the implementation
338 		** guarantees can be opened."
339 		*/
340 		char		fullname[FILENAME_MAX + 1];
341 
342 		if (name[0] == ':')
343 			++name;
344 		doaccess = name[0] == '/';
345 		if (!doaccess) {
346 			if ((p = TZDIR) == NULL)
347 				return -1;
348 			if ((strlen(p) + strlen(name) + 1) >= sizeof fullname)
349 				return -1;
350 			(void) strcpy(fullname, p);	/* XXX strcpy is safe */
351 			(void) strcat(fullname, "/");	/* XXX strcat is safe */
352 			(void) strcat(fullname, name);	/* XXX strcat is safe */
353 			/*
354 			** Set doaccess if '.' (as in "../") shows up in name.
355 			*/
356 			if (strchr(name, '.') != NULL)
357 				doaccess = TRUE;
358 			name = fullname;
359 		}
360 		if (doaccess && access(name, R_OK) != 0)
361 			return -1;
362 		/*
363 		 * XXX potential security problem here if user of a set-id
364 		 * program has set TZ (which is passed in as name) here,
365 		 * and uses a race condition trick to defeat the access(2)
366 		 * above.
367 		 */
368 		if ((fid = open(name, OPEN_MODE)) == -1)
369 			return -1;
370 	}
371 	{
372 		struct tzhead *	tzhp;
373 		union {
374 		  struct tzhead tzhead;
375 		  char		buf[sizeof *sp + sizeof *tzhp];
376 		} u;
377 		int		ttisstdcnt;
378 		int		ttisgmtcnt;
379 
380 		i = read(fid, u.buf, sizeof u.buf);
381 		if (close(fid) != 0)
382 			return -1;
383 		ttisstdcnt = (int) detzcode(u.tzhead.tzh_ttisgmtcnt);
384 		ttisgmtcnt = (int) detzcode(u.tzhead.tzh_ttisstdcnt);
385 		sp->leapcnt = (int) detzcode(u.tzhead.tzh_leapcnt);
386 		sp->timecnt = (int) detzcode(u.tzhead.tzh_timecnt);
387 		sp->typecnt = (int) detzcode(u.tzhead.tzh_typecnt);
388 		sp->charcnt = (int) detzcode(u.tzhead.tzh_charcnt);
389 		p = u.tzhead.tzh_charcnt + sizeof u.tzhead.tzh_charcnt;
390 		if (sp->leapcnt < 0 || sp->leapcnt > TZ_MAX_LEAPS ||
391 			sp->typecnt <= 0 || sp->typecnt > TZ_MAX_TYPES ||
392 			sp->timecnt < 0 || sp->timecnt > TZ_MAX_TIMES ||
393 			sp->charcnt < 0 || sp->charcnt > TZ_MAX_CHARS ||
394 			(ttisstdcnt != sp->typecnt && ttisstdcnt != 0) ||
395 			(ttisgmtcnt != sp->typecnt && ttisgmtcnt != 0))
396 				return -1;
397 		if (i - (p - u.buf) < sp->timecnt * 4 +	/* ats */
398 			sp->timecnt +			/* types */
399 			sp->typecnt * (4 + 2) +		/* ttinfos */
400 			sp->charcnt +			/* chars */
401 			sp->leapcnt * (4 + 4) +		/* lsinfos */
402 			ttisstdcnt +			/* ttisstds */
403 			ttisgmtcnt)			/* ttisgmts */
404 				return -1;
405 		for (i = 0; i < sp->timecnt; ++i) {
406 			sp->ats[i] = detzcode(p);
407 			p += 4;
408 		}
409 		for (i = 0; i < sp->timecnt; ++i) {
410 			sp->types[i] = (unsigned char) *p++;
411 			if (sp->types[i] >= sp->typecnt)
412 				return -1;
413 		}
414 		for (i = 0; i < sp->typecnt; ++i) {
415 			register struct ttinfo *	ttisp;
416 
417 			ttisp = &sp->ttis[i];
418 			ttisp->tt_gmtoff = detzcode(p);
419 			p += 4;
420 			ttisp->tt_isdst = (unsigned char) *p++;
421 			if (ttisp->tt_isdst != 0 && ttisp->tt_isdst != 1)
422 				return -1;
423 			ttisp->tt_abbrind = (unsigned char) *p++;
424 			if (ttisp->tt_abbrind < 0 ||
425 				ttisp->tt_abbrind > sp->charcnt)
426 					return -1;
427 		}
428 		for (i = 0; i < sp->charcnt; ++i)
429 			sp->chars[i] = *p++;
430 		sp->chars[i] = '\0';	/* ensure '\0' at end */
431 		for (i = 0; i < sp->leapcnt; ++i) {
432 			register struct lsinfo *	lsisp;
433 
434 			lsisp = &sp->lsis[i];
435 			lsisp->ls_trans = detzcode(p);
436 			p += 4;
437 			lsisp->ls_corr = detzcode(p);
438 			p += 4;
439 		}
440 		for (i = 0; i < sp->typecnt; ++i) {
441 			register struct ttinfo *	ttisp;
442 
443 			ttisp = &sp->ttis[i];
444 			if (ttisstdcnt == 0)
445 				ttisp->tt_ttisstd = FALSE;
446 			else {
447 				ttisp->tt_ttisstd = *p++;
448 				if (ttisp->tt_ttisstd != TRUE &&
449 					ttisp->tt_ttisstd != FALSE)
450 						return -1;
451 			}
452 		}
453 		for (i = 0; i < sp->typecnt; ++i) {
454 			register struct ttinfo *	ttisp;
455 
456 			ttisp = &sp->ttis[i];
457 			if (ttisgmtcnt == 0)
458 				ttisp->tt_ttisgmt = FALSE;
459 			else {
460 				ttisp->tt_ttisgmt = *p++;
461 				if (ttisp->tt_ttisgmt != TRUE &&
462 					ttisp->tt_ttisgmt != FALSE)
463 						return -1;
464 			}
465 		}
466 	}
467 	return 0;
468 }
469 
470 static const int	mon_lengths[2][MONSPERYEAR] = {
471 	{ 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 },
472 	{ 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }
473 };
474 
475 static const int	year_lengths[2] = {
476 	DAYSPERNYEAR, DAYSPERLYEAR
477 };
478 
479 /*
480 ** Given a pointer into a time zone string, scan until a character that is not
481 ** a valid character in a zone name is found.  Return a pointer to that
482 ** character.
483 */
484 
485 static const char *
486 getzname(strp)
487 register const char *	strp;
488 {
489 	register char	c;
490 
491 	while ((c = *strp) != '\0' && !is_digit(c) && c != ',' && c != '-' &&
492 		c != '+')
493 			++strp;
494 	return strp;
495 }
496 
497 /*
498 ** Given a pointer into a time zone string, extract a number from that string.
499 ** Check that the number is within a specified range; if it is not, return
500 ** NULL.
501 ** Otherwise, return a pointer to the first character not part of the number.
502 */
503 
504 static const char *
505 getnum(strp, nump, min, max)
506 register const char *	strp;
507 int * const		nump;
508 const int		min;
509 const int		max;
510 {
511 	register char	c;
512 	register int	num;
513 
514 	if (strp == NULL || !is_digit(c = *strp))
515 		return NULL;
516 	num = 0;
517 	do {
518 		num = num * 10 + (c - '0');
519 		if (num > max)
520 			return NULL;	/* illegal value */
521 		c = *++strp;
522 	} while (is_digit(c));
523 	if (num < min)
524 		return NULL;		/* illegal value */
525 	*nump = num;
526 	return strp;
527 }
528 
529 /*
530 ** Given a pointer into a time zone string, extract a number of seconds,
531 ** in hh[:mm[:ss]] form, from the string.
532 ** If any error occurs, return NULL.
533 ** Otherwise, return a pointer to the first character not part of the number
534 ** of seconds.
535 */
536 
537 static const char *
538 getsecs(strp, secsp)
539 register const char *	strp;
540 long * const		secsp;
541 {
542 	int	num;
543 
544 	/*
545 	** `HOURSPERDAY * DAYSPERWEEK - 1' allows quasi-Posix rules like
546 	** "M10.4.6/26", which does not conform to Posix,
547 	** but which specifies the equivalent of
548 	** ``02:00 on the first Sunday on or after 23 Oct''.
549 	*/
550 	strp = getnum(strp, &num, 0, HOURSPERDAY * DAYSPERWEEK - 1);
551 	if (strp == NULL)
552 		return NULL;
553 	*secsp = num * (long) SECSPERHOUR;
554 	if (*strp == ':') {
555 		++strp;
556 		strp = getnum(strp, &num, 0, MINSPERHOUR - 1);
557 		if (strp == NULL)
558 			return NULL;
559 		*secsp += num * SECSPERMIN;
560 		if (*strp == ':') {
561 			++strp;
562 			/* `SECSPERMIN' allows for leap seconds.  */
563 			strp = getnum(strp, &num, 0, SECSPERMIN);
564 			if (strp == NULL)
565 				return NULL;
566 			*secsp += num;
567 		}
568 	}
569 	return strp;
570 }
571 
572 /*
573 ** Given a pointer into a time zone string, extract an offset, in
574 ** [+-]hh[:mm[:ss]] form, from the string.
575 ** If any error occurs, return NULL.
576 ** Otherwise, return a pointer to the first character not part of the time.
577 */
578 
579 static const char *
580 getoffset(strp, offsetp)
581 register const char *	strp;
582 long * const		offsetp;
583 {
584 	register int	neg = 0;
585 
586 	if (*strp == '-') {
587 		neg = 1;
588 		++strp;
589 	} else if (*strp == '+')
590 		++strp;
591 	strp = getsecs(strp, offsetp);
592 	if (strp == NULL)
593 		return NULL;		/* illegal time */
594 	if (neg)
595 		*offsetp = -*offsetp;
596 	return strp;
597 }
598 
599 /*
600 ** Given a pointer into a time zone string, extract a rule in the form
601 ** date[/time].  See POSIX section 8 for the format of "date" and "time".
602 ** If a valid rule is not found, return NULL.
603 ** Otherwise, return a pointer to the first character not part of the rule.
604 */
605 
606 static const char *
607 getrule(strp, rulep)
608 const char *			strp;
609 register struct rule * const	rulep;
610 {
611 	if (*strp == 'J') {
612 		/*
613 		** Julian day.
614 		*/
615 		rulep->r_type = JULIAN_DAY;
616 		++strp;
617 		strp = getnum(strp, &rulep->r_day, 1, DAYSPERNYEAR);
618 	} else if (*strp == 'M') {
619 		/*
620 		** Month, week, day.
621 		*/
622 		rulep->r_type = MONTH_NTH_DAY_OF_WEEK;
623 		++strp;
624 		strp = getnum(strp, &rulep->r_mon, 1, MONSPERYEAR);
625 		if (strp == NULL)
626 			return NULL;
627 		if (*strp++ != '.')
628 			return NULL;
629 		strp = getnum(strp, &rulep->r_week, 1, 5);
630 		if (strp == NULL)
631 			return NULL;
632 		if (*strp++ != '.')
633 			return NULL;
634 		strp = getnum(strp, &rulep->r_day, 0, DAYSPERWEEK - 1);
635 	} else if (is_digit(*strp)) {
636 		/*
637 		** Day of year.
638 		*/
639 		rulep->r_type = DAY_OF_YEAR;
640 		strp = getnum(strp, &rulep->r_day, 0, DAYSPERLYEAR - 1);
641 	} else	return NULL;		/* invalid format */
642 	if (strp == NULL)
643 		return NULL;
644 	if (*strp == '/') {
645 		/*
646 		** Time specified.
647 		*/
648 		++strp;
649 		strp = getsecs(strp, &rulep->r_time);
650 	} else	rulep->r_time = 2 * SECSPERHOUR;	/* default = 2:00:00 */
651 	return strp;
652 }
653 
654 /*
655 ** Given the Epoch-relative time of January 1, 00:00:00 UTC, in a year, the
656 ** year, a rule, and the offset from UTC at the time that rule takes effect,
657 ** calculate the Epoch-relative time that rule takes effect.
658 */
659 
660 static time_t
661 transtime(janfirst, year, rulep, offset)
662 const time_t				janfirst;
663 const int				year;
664 register const struct rule * const	rulep;
665 const long				offset;
666 {
667 	register int	leapyear;
668 	register time_t	value;
669 	register int	i;
670 	int		d, m1, yy0, yy1, yy2, dow;
671 
672 	INITIALIZE(value);
673 	leapyear = isleap(year);
674 	switch (rulep->r_type) {
675 
676 	case JULIAN_DAY:
677 		/*
678 		** Jn - Julian day, 1 == January 1, 60 == March 1 even in leap
679 		** years.
680 		** In non-leap years, or if the day number is 59 or less, just
681 		** add SECSPERDAY times the day number-1 to the time of
682 		** January 1, midnight, to get the day.
683 		*/
684 		value = janfirst + (rulep->r_day - 1) * SECSPERDAY;
685 		if (leapyear && rulep->r_day >= 60)
686 			value += SECSPERDAY;
687 		break;
688 
689 	case DAY_OF_YEAR:
690 		/*
691 		** n - day of year.
692 		** Just add SECSPERDAY times the day number to the time of
693 		** January 1, midnight, to get the day.
694 		*/
695 		value = janfirst + rulep->r_day * SECSPERDAY;
696 		break;
697 
698 	case MONTH_NTH_DAY_OF_WEEK:
699 		/*
700 		** Mm.n.d - nth "dth day" of month m.
701 		*/
702 		value = janfirst;
703 		for (i = 0; i < rulep->r_mon - 1; ++i)
704 			value += mon_lengths[leapyear][i] * SECSPERDAY;
705 
706 		/*
707 		** Use Zeller's Congruence to get day-of-week of first day of
708 		** month.
709 		*/
710 		m1 = (rulep->r_mon + 9) % 12 + 1;
711 		yy0 = (rulep->r_mon <= 2) ? (year - 1) : year;
712 		yy1 = yy0 / 100;
713 		yy2 = yy0 % 100;
714 		dow = ((26 * m1 - 2) / 10 +
715 			1 + yy2 + yy2 / 4 + yy1 / 4 - 2 * yy1) % 7;
716 		if (dow < 0)
717 			dow += DAYSPERWEEK;
718 
719 		/*
720 		** "dow" is the day-of-week of the first day of the month.  Get
721 		** the day-of-month (zero-origin) of the first "dow" day of the
722 		** month.
723 		*/
724 		d = rulep->r_day - dow;
725 		if (d < 0)
726 			d += DAYSPERWEEK;
727 		for (i = 1; i < rulep->r_week; ++i) {
728 			if (d + DAYSPERWEEK >=
729 				mon_lengths[leapyear][rulep->r_mon - 1])
730 					break;
731 			d += DAYSPERWEEK;
732 		}
733 
734 		/*
735 		** "d" is the day-of-month (zero-origin) of the day we want.
736 		*/
737 		value += d * SECSPERDAY;
738 		break;
739 	}
740 
741 	/*
742 	** "value" is the Epoch-relative time of 00:00:00 UTC on the day in
743 	** question.  To get the Epoch-relative time of the specified local
744 	** time on that day, add the transition time and the current offset
745 	** from UTC.
746 	*/
747 	return value + rulep->r_time + offset;
748 }
749 
750 /*
751 ** Given a POSIX section 8-style TZ string, fill in the rule tables as
752 ** appropriate.
753 */
754 
755 static int
756 tzparse(name, sp, lastditch)
757 const char *			name;
758 register struct state * const	sp;
759 const int			lastditch;
760 {
761 	const char *			stdname;
762 	const char *			dstname;
763 	size_t				stdlen;
764 	size_t				dstlen;
765 	long				stdoffset;
766 	long				dstoffset;
767 	register time_t *		atp;
768 	register unsigned char *	typep;
769 	register char *			cp;
770 	register int			load_result;
771 
772 	INITIALIZE(dstname);
773 	stdname = name;
774 	if (lastditch) {
775 		stdlen = strlen(name);	/* length of standard zone name */
776 		name += stdlen;
777 		if (stdlen >= sizeof sp->chars)
778 			stdlen = (sizeof sp->chars) - 1;
779 		stdoffset = 0;
780 	} else {
781 		name = getzname(name);
782 		stdlen = name - stdname;
783 		if (stdlen < 3)
784 			return -1;
785 		if (*name == '\0')
786 			return -1;
787 		name = getoffset(name, &stdoffset);
788 		if (name == NULL)
789 			return -1;
790 	}
791 	load_result = tzload(TZDEFRULES, sp);
792 	if (load_result != 0)
793 		sp->leapcnt = 0;		/* so, we're off a little */
794 	if (*name != '\0') {
795 		dstname = name;
796 		name = getzname(name);
797 		dstlen = name - dstname;	/* length of DST zone name */
798 		if (dstlen < 3)
799 			return -1;
800 		if (*name != '\0' && *name != ',' && *name != ';') {
801 			name = getoffset(name, &dstoffset);
802 			if (name == NULL)
803 				return -1;
804 		} else	dstoffset = stdoffset - SECSPERHOUR;
805 		if (*name == '\0' && load_result != 0)
806 			name = TZDEFRULESTRING;
807 		if (*name == ',' || *name == ';') {
808 			struct rule	start;
809 			struct rule	end;
810 			register int	year;
811 			register time_t	janfirst;
812 			time_t		starttime;
813 			time_t		endtime;
814 
815 			++name;
816 			if ((name = getrule(name, &start)) == NULL)
817 				return -1;
818 			if (*name++ != ',')
819 				return -1;
820 			if ((name = getrule(name, &end)) == NULL)
821 				return -1;
822 			if (*name != '\0')
823 				return -1;
824 			sp->typecnt = 2;	/* standard time and DST */
825 			/*
826 			** Two transitions per year, from EPOCH_YEAR to 2037.
827 			*/
828 			sp->timecnt = 2 * (2037 - EPOCH_YEAR + 1);
829 			if (sp->timecnt > TZ_MAX_TIMES)
830 				return -1;
831 			sp->ttis[0].tt_gmtoff = -dstoffset;
832 			sp->ttis[0].tt_isdst = 1;
833 			sp->ttis[0].tt_abbrind = stdlen + 1;
834 			sp->ttis[1].tt_gmtoff = -stdoffset;
835 			sp->ttis[1].tt_isdst = 0;
836 			sp->ttis[1].tt_abbrind = 0;
837 			atp = sp->ats;
838 			typep = sp->types;
839 			janfirst = 0;
840 			for (year = EPOCH_YEAR; year <= 2037; ++year) {
841 				starttime = transtime(janfirst, year, &start,
842 					stdoffset);
843 				endtime = transtime(janfirst, year, &end,
844 					dstoffset);
845 				if (starttime > endtime) {
846 					*atp++ = endtime;
847 					*typep++ = 1;	/* DST ends */
848 					*atp++ = starttime;
849 					*typep++ = 0;	/* DST begins */
850 				} else {
851 					*atp++ = starttime;
852 					*typep++ = 0;	/* DST begins */
853 					*atp++ = endtime;
854 					*typep++ = 1;	/* DST ends */
855 				}
856 				janfirst += year_lengths[isleap(year)] *
857 					SECSPERDAY;
858 			}
859 		} else {
860 			register long	theirstdoffset;
861 			register long	theirdstoffset;
862 			register long	theiroffset;
863 			register int	isdst;
864 			register int	i;
865 			register int	j;
866 
867 			if (*name != '\0')
868 				return -1;
869 			/*
870 			** Initial values of theirstdoffset and theirdstoffset.
871 			*/
872 			theirstdoffset = 0;
873 			for (i = 0; i < sp->timecnt; ++i) {
874 				j = sp->types[i];
875 				if (!sp->ttis[j].tt_isdst) {
876 					theirstdoffset =
877 						-sp->ttis[j].tt_gmtoff;
878 					break;
879 				}
880 			}
881 			theirdstoffset = 0;
882 			for (i = 0; i < sp->timecnt; ++i) {
883 				j = sp->types[i];
884 				if (sp->ttis[j].tt_isdst) {
885 					theirdstoffset =
886 						-sp->ttis[j].tt_gmtoff;
887 					break;
888 				}
889 			}
890 			/*
891 			** Initially we're assumed to be in standard time.
892 			*/
893 			isdst = FALSE;
894 			theiroffset = theirstdoffset;
895 			/*
896 			** Now juggle transition times and types
897 			** tracking offsets as you do.
898 			*/
899 			for (i = 0; i < sp->timecnt; ++i) {
900 				j = sp->types[i];
901 				sp->types[i] = sp->ttis[j].tt_isdst;
902 				if (sp->ttis[j].tt_ttisgmt) {
903 					/* No adjustment to transition time */
904 				} else {
905 					/*
906 					** If summer time is in effect, and the
907 					** transition time was not specified as
908 					** standard time, add the summer time
909 					** offset to the transition time;
910 					** otherwise, add the standard time
911 					** offset to the transition time.
912 					*/
913 					/*
914 					** Transitions from DST to DDST
915 					** will effectively disappear since
916 					** POSIX provides for only one DST
917 					** offset.
918 					*/
919 					if (isdst && !sp->ttis[j].tt_ttisstd) {
920 						sp->ats[i] += dstoffset -
921 							theirdstoffset;
922 					} else {
923 						sp->ats[i] += stdoffset -
924 							theirstdoffset;
925 					}
926 				}
927 				theiroffset = -sp->ttis[j].tt_gmtoff;
928 				if (sp->ttis[j].tt_isdst)
929 					theirdstoffset = theiroffset;
930 				else	theirstdoffset = theiroffset;
931 			}
932 			/*
933 			** Finally, fill in ttis.
934 			** ttisstd and ttisgmt need not be handled.
935 			*/
936 			sp->ttis[0].tt_gmtoff = -stdoffset;
937 			sp->ttis[0].tt_isdst = FALSE;
938 			sp->ttis[0].tt_abbrind = 0;
939 			sp->ttis[1].tt_gmtoff = -dstoffset;
940 			sp->ttis[1].tt_isdst = TRUE;
941 			sp->ttis[1].tt_abbrind = stdlen + 1;
942 			sp->typecnt = 2;
943 		}
944 	} else {
945 		dstlen = 0;
946 		sp->typecnt = 1;		/* only standard time */
947 		sp->timecnt = 0;
948 		sp->ttis[0].tt_gmtoff = -stdoffset;
949 		sp->ttis[0].tt_isdst = 0;
950 		sp->ttis[0].tt_abbrind = 0;
951 	}
952 	sp->charcnt = stdlen + 1;
953 	if (dstlen != 0)
954 		sp->charcnt += dstlen + 1;
955 	if ((size_t) sp->charcnt > sizeof sp->chars)
956 		return -1;
957 	cp = sp->chars;
958 	(void) strncpy(cp, stdname, stdlen);
959 	cp += stdlen;
960 	*cp++ = '\0';
961 	if (dstlen != 0) {
962 		(void) strncpy(cp, dstname, dstlen);
963 		*(cp + dstlen) = '\0';
964 	}
965 	return 0;
966 }
967 
968 static void
969 gmtload(sp)
970 struct state * const	sp;
971 {
972 	if (tzload(gmt, sp) != 0)
973 		(void) tzparse(gmt, sp, TRUE);
974 }
975 
976 static void
977 tzsetwall_unlocked P((void))
978 {
979 	if (lcl_is_set < 0)
980 		return;
981 	lcl_is_set = -1;
982 
983 #ifdef ALL_STATE
984 	if (lclptr == NULL) {
985 		lclptr = (struct state *) malloc(sizeof *lclptr);
986 		if (lclptr == NULL) {
987 			settzname();	/* all we can do */
988 			return;
989 		}
990 	}
991 #endif /* defined ALL_STATE */
992 	if (tzload((char *) NULL, lclptr) != 0)
993 		gmtload(lclptr);
994 	settzname();
995 }
996 
997 #ifndef STD_INSPIRED
998 /*
999 ** A non-static declaration of tzsetwall in a system header file
1000 ** may cause a warning about this upcoming static declaration...
1001 */
1002 static
1003 #endif /* !defined STD_INSPIRED */
1004 void
1005 tzsetwall P((void))
1006 {
1007 	rwlock_wrlock(&lcl_lock);
1008 	tzsetwall_unlocked();
1009 	rwlock_unlock(&lcl_lock);
1010 }
1011 
1012 static void
1013 tzset_unlocked P((void))
1014 {
1015 	register const char *	name;
1016 
1017 	name = getenv("TZ");
1018 	if (name == NULL) {
1019 		tzsetwall_unlocked();
1020 		return;
1021 	}
1022 
1023 	if (lcl_is_set > 0  &&  strcmp(lcl_TZname, name) == 0)
1024 		return;
1025 	lcl_is_set = (strlen(name) < sizeof(lcl_TZname));
1026 	if (lcl_is_set)
1027 		(void)strncpy(lcl_TZname, name, sizeof(lcl_TZname) - 1);
1028 
1029 #ifdef ALL_STATE
1030 	if (lclptr == NULL) {
1031 		lclptr = (struct state *) malloc(sizeof *lclptr);
1032 		if (lclptr == NULL) {
1033 			settzname();	/* all we can do */
1034 			return;
1035 		}
1036 	}
1037 #endif /* defined ALL_STATE */
1038 	if (*name == '\0') {
1039 		/*
1040 		** User wants it fast rather than right.
1041 		*/
1042 		lclptr->leapcnt = 0;		/* so, we're off a little */
1043 		lclptr->timecnt = 0;
1044 		lclptr->ttis[0].tt_gmtoff = 0;
1045 		lclptr->ttis[0].tt_abbrind = 0;
1046 		(void)strncpy(lclptr->chars, gmt, sizeof(lclptr->chars) - 1);
1047 	} else if (tzload(name, lclptr) != 0)
1048 		if (name[0] == ':' || tzparse(name, lclptr, FALSE) != 0)
1049 			(void) gmtload(lclptr);
1050 	settzname();
1051 }
1052 
1053 void
1054 tzset P((void))
1055 {
1056 	rwlock_wrlock(&lcl_lock);
1057 	tzset_unlocked();
1058 	rwlock_unlock(&lcl_lock);
1059 }
1060 
1061 /*
1062 ** The easy way to behave "as if no library function calls" localtime
1063 ** is to not call it--so we drop its guts into "localsub", which can be
1064 ** freely called.  (And no, the PANS doesn't require the above behavior--
1065 ** but it *is* desirable.)
1066 **
1067 ** The unused offset argument is for the benefit of mktime variants.
1068 */
1069 
1070 /*ARGSUSED*/
1071 static void
1072 localsub(timep, offset, tmp)
1073 const time_t * const	timep;
1074 const long		offset;
1075 struct tm * const	tmp;
1076 {
1077 	register struct state *		sp;
1078 	register const struct ttinfo *	ttisp;
1079 	register int			i;
1080 	const time_t			t = *timep;
1081 
1082 	sp = lclptr;
1083 #ifdef ALL_STATE
1084 	if (sp == NULL) {
1085 		gmtsub(timep, offset, tmp);
1086 		return;
1087 	}
1088 #endif /* defined ALL_STATE */
1089 	if (sp->timecnt == 0 || t < sp->ats[0]) {
1090 		i = 0;
1091 		while (sp->ttis[i].tt_isdst)
1092 			if (++i >= sp->typecnt) {
1093 				i = 0;
1094 				break;
1095 			}
1096 	} else {
1097 		for (i = 1; i < sp->timecnt; ++i)
1098 			if (t < sp->ats[i])
1099 				break;
1100 		i = sp->types[i - 1];
1101 	}
1102 	ttisp = &sp->ttis[i];
1103 	/*
1104 	** To get (wrong) behavior that's compatible with System V Release 2.0
1105 	** you'd replace the statement below with
1106 	**	t += ttisp->tt_gmtoff;
1107 	**	timesub(&t, 0L, sp, tmp);
1108 	*/
1109 	timesub(&t, ttisp->tt_gmtoff, sp, tmp);
1110 	tmp->tm_isdst = ttisp->tt_isdst;
1111 	tzname[tmp->tm_isdst] = &sp->chars[ttisp->tt_abbrind];
1112 #ifdef TM_ZONE
1113 	tmp->TM_ZONE = &sp->chars[ttisp->tt_abbrind];
1114 #endif /* defined TM_ZONE */
1115 }
1116 
1117 struct tm *
1118 localtime(timep)
1119 const time_t * const	timep;
1120 {
1121 	rwlock_wrlock(&lcl_lock);
1122 	tzset_unlocked();
1123 	localsub(timep, 0L, &tm);
1124 	rwlock_unlock(&lcl_lock);
1125 	return &tm;
1126 }
1127 
1128 /*
1129  * Re-entrant version of localtime
1130  */
1131 struct tm *
1132 localtime_r(timep, tm)
1133 const time_t * const	timep;
1134 struct tm *		tm;
1135 {
1136 	rwlock_rdlock(&lcl_lock);
1137 	localsub(timep, 0L, tm);
1138 	rwlock_unlock(&lcl_lock);
1139 	return tm;
1140 }
1141 
1142 /*
1143 ** gmtsub is to gmtime as localsub is to localtime.
1144 */
1145 
1146 static void
1147 gmtsub(timep, offset, tmp)
1148 const time_t * const	timep;
1149 const long		offset;
1150 struct tm * const	tmp;
1151 {
1152 #ifdef _REENT
1153 	static mutex_t gmt_mutex = MUTEX_INITIALIZER;
1154 #endif
1155 
1156 	mutex_lock(&gmt_mutex);
1157 	if (!gmt_is_set) {
1158 		gmt_is_set = TRUE;
1159 #ifdef ALL_STATE
1160 		gmtptr = (struct state *) malloc(sizeof *gmtptr);
1161 		if (gmtptr != NULL)
1162 #endif /* defined ALL_STATE */
1163 			gmtload(gmtptr);
1164 	}
1165 	mutex_unlock(&gmt_mutex);
1166 	timesub(timep, offset, gmtptr, tmp);
1167 #ifdef TM_ZONE
1168 	/*
1169 	** Could get fancy here and deliver something such as
1170 	** "UTC+xxxx" or "UTC-xxxx" if offset is non-zero,
1171 	** but this is no time for a treasure hunt.
1172 	*/
1173 	if (offset != 0)
1174 		/* LINTED const castaway */
1175 		tmp->TM_ZONE = (__aconst char *)wildabbr;
1176 	else {
1177 #ifdef ALL_STATE
1178 		if (gmtptr == NULL)
1179 			tmp->TM_ZONE = (__aconst char *)gmt;
1180 		else	tmp->TM_ZONE = gmtptr->chars;
1181 #endif /* defined ALL_STATE */
1182 #ifndef ALL_STATE
1183 		tmp->TM_ZONE = gmtptr->chars;
1184 #endif /* State Farm */
1185 	}
1186 #endif /* defined TM_ZONE */
1187 }
1188 
1189 struct tm *
1190 gmtime(timep)
1191 const time_t * const	timep;
1192 {
1193 	gmtsub(timep, 0L, &tm);
1194 	return &tm;
1195 }
1196 
1197 /*
1198  * Re-entrant version of gmtime
1199  */
1200 struct tm *
1201 gmtime_r(timep, tm)
1202 const time_t * const	timep;
1203 struct tm *		tm;
1204 {
1205 	gmtsub(timep, 0L, tm);
1206 	return tm;
1207 }
1208 
1209 #ifdef STD_INSPIRED
1210 
1211 struct tm *
1212 offtime(timep, offset)
1213 const time_t * const	timep;
1214 const long		offset;
1215 {
1216 	gmtsub(timep, offset, &tm);
1217 	return &tm;
1218 }
1219 
1220 #endif /* defined STD_INSPIRED */
1221 
1222 static void
1223 timesub(timep, offset, sp, tmp)
1224 const time_t * const			timep;
1225 const long				offset;
1226 register const struct state * const	sp;
1227 register struct tm * const		tmp;
1228 {
1229 	register const struct lsinfo *	lp;
1230 	register long			days;
1231 	register long			rem;
1232 	register int			y;
1233 	register int			yleap;
1234 	register const int *		ip;
1235 	register long			corr;
1236 	register int			hit;
1237 	register int			i;
1238 
1239 	corr = 0;
1240 	hit = 0;
1241 #ifdef ALL_STATE
1242 	i = (sp == NULL) ? 0 : sp->leapcnt;
1243 #endif /* defined ALL_STATE */
1244 #ifndef ALL_STATE
1245 	i = sp->leapcnt;
1246 #endif /* State Farm */
1247 	while (--i >= 0) {
1248 		lp = &sp->lsis[i];
1249 		if (*timep >= lp->ls_trans) {
1250 			if (*timep == lp->ls_trans) {
1251 				hit = ((i == 0 && lp->ls_corr > 0) ||
1252 					lp->ls_corr > sp->lsis[i - 1].ls_corr);
1253 				if (hit)
1254 					while (i > 0 &&
1255 						sp->lsis[i].ls_trans ==
1256 						sp->lsis[i - 1].ls_trans + 1 &&
1257 						sp->lsis[i].ls_corr ==
1258 						sp->lsis[i - 1].ls_corr + 1) {
1259 							++hit;
1260 							--i;
1261 					}
1262 			}
1263 			corr = lp->ls_corr;
1264 			break;
1265 		}
1266 	}
1267 	days = *timep / SECSPERDAY;
1268 	rem = *timep % SECSPERDAY;
1269 #ifdef mc68k
1270 	if (*timep == 0x80000000) {
1271 		/*
1272 		** A 3B1 muffs the division on the most negative number.
1273 		*/
1274 		days = -24855;
1275 		rem = -11648;
1276 	}
1277 #endif /* defined mc68k */
1278 	rem += (offset - corr);
1279 	while (rem < 0) {
1280 		rem += SECSPERDAY;
1281 		--days;
1282 	}
1283 	while (rem >= SECSPERDAY) {
1284 		rem -= SECSPERDAY;
1285 		++days;
1286 	}
1287 	tmp->tm_hour = (int) (rem / SECSPERHOUR);
1288 	rem = rem % SECSPERHOUR;
1289 	tmp->tm_min = (int) (rem / SECSPERMIN);
1290 	/*
1291 	** A positive leap second requires a special
1292 	** representation.  This uses "... ??:59:60" et seq.
1293 	*/
1294 	tmp->tm_sec = (int) (rem % SECSPERMIN) + hit;
1295 	tmp->tm_wday = (int) ((EPOCH_WDAY + days) % DAYSPERWEEK);
1296 	if (tmp->tm_wday < 0)
1297 		tmp->tm_wday += DAYSPERWEEK;
1298 	y = EPOCH_YEAR;
1299 #define LEAPS_THRU_END_OF(y)	((y) / 4 - (y) / 100 + (y) / 400)
1300 	while (days < 0 || days >= (long) year_lengths[yleap = isleap(y)]) {
1301 		register int	newy;
1302 
1303 		newy = (int)(y + days / DAYSPERNYEAR);
1304 		if (days < 0)
1305 			--newy;
1306 		days -= (newy - y) * DAYSPERNYEAR +
1307 			LEAPS_THRU_END_OF(newy - 1) -
1308 			LEAPS_THRU_END_OF(y - 1);
1309 		y = newy;
1310 	}
1311 	tmp->tm_year = y - TM_YEAR_BASE;
1312 	tmp->tm_yday = (int) days;
1313 	ip = mon_lengths[yleap];
1314 	for (tmp->tm_mon = 0; days >= (long) ip[tmp->tm_mon]; ++(tmp->tm_mon))
1315 		days = days - (long) ip[tmp->tm_mon];
1316 	tmp->tm_mday = (int) (days + 1);
1317 	tmp->tm_isdst = 0;
1318 #ifdef TM_GMTOFF
1319 	tmp->TM_GMTOFF = offset;
1320 #endif /* defined TM_GMTOFF */
1321 }
1322 
1323 char *
1324 ctime(timep)
1325 const time_t * const	timep;
1326 {
1327 /*
1328 ** Section 4.12.3.2 of X3.159-1989 requires that
1329 **	The ctime function converts the calendar time pointed to by timer
1330 **	to local time in the form of a string.  It is equivalent to
1331 **		asctime(localtime(timer))
1332 */
1333 	return asctime(localtime(timep));
1334 }
1335 
1336 char *
1337 ctime_r(timep, buf)
1338 const time_t * const	timep;
1339 char *			buf;
1340 {
1341 	struct tm	tmp;
1342 
1343 	return asctime_r(localtime_r(timep, &tmp), buf);
1344 }
1345 
1346 /*
1347 ** Adapted from code provided by Robert Elz, who writes:
1348 **	The "best" way to do mktime I think is based on an idea of Bob
1349 **	Kridle's (so its said...) from a long time ago.
1350 **	[kridle@xinet.com as of 1996-01-16.]
1351 **	It does a binary search of the time_t space.  Since time_t's are
1352 **	just 32 bits, its a max of 32 iterations (even at 64 bits it
1353 **	would still be very reasonable).
1354 */
1355 
1356 #ifndef WRONG
1357 #define WRONG	(-1)
1358 #endif /* !defined WRONG */
1359 
1360 /*
1361 ** Simplified normalize logic courtesy Paul Eggert (eggert@twinsun.com).
1362 */
1363 
1364 static int
1365 increment_overflow(number, delta)
1366 int *	number;
1367 int	delta;
1368 {
1369 	int	number0;
1370 
1371 	number0 = *number;
1372 	*number += delta;
1373 	return (*number < number0) != (delta < 0);
1374 }
1375 
1376 static int
1377 normalize_overflow(tensptr, unitsptr, base)
1378 int * const	tensptr;
1379 int * const	unitsptr;
1380 const int	base;
1381 {
1382 	register int	tensdelta;
1383 
1384 	tensdelta = (*unitsptr >= 0) ?
1385 		(*unitsptr / base) :
1386 		(-1 - (-1 - *unitsptr) / base);
1387 	*unitsptr -= tensdelta * base;
1388 	return increment_overflow(tensptr, tensdelta);
1389 }
1390 
1391 static int
1392 tmcomp(atmp, btmp)
1393 register const struct tm * const atmp;
1394 register const struct tm * const btmp;
1395 {
1396 	register int	result;
1397 
1398 	if ((result = (atmp->tm_year - btmp->tm_year)) == 0 &&
1399 		(result = (atmp->tm_mon - btmp->tm_mon)) == 0 &&
1400 		(result = (atmp->tm_mday - btmp->tm_mday)) == 0 &&
1401 		(result = (atmp->tm_hour - btmp->tm_hour)) == 0 &&
1402 		(result = (atmp->tm_min - btmp->tm_min)) == 0)
1403 			result = atmp->tm_sec - btmp->tm_sec;
1404 	return result;
1405 }
1406 
1407 static time_t
1408 time2sub(tmp, funcp, offset, okayp, do_norm_secs)
1409 struct tm * const	tmp;
1410 void (* const		funcp) P((const time_t*, long, struct tm*));
1411 const long		offset;
1412 int * const		okayp;
1413 const int		do_norm_secs;
1414 {
1415 	register const struct state *	sp;
1416 	register int			dir;
1417 	register int			bits;
1418 	register int			i, j ;
1419 	register int			saved_seconds;
1420 	time_t				newt;
1421 	time_t				t;
1422 	struct tm			yourtm, mytm;
1423 
1424 	*okayp = FALSE;
1425 	yourtm = *tmp;
1426 	if (do_norm_secs) {
1427 		if (normalize_overflow(&yourtm.tm_min, &yourtm.tm_sec,
1428 			SECSPERMIN))
1429 				return WRONG;
1430 	}
1431 	if (normalize_overflow(&yourtm.tm_hour, &yourtm.tm_min, MINSPERHOUR))
1432 		return WRONG;
1433 	if (normalize_overflow(&yourtm.tm_mday, &yourtm.tm_hour, HOURSPERDAY))
1434 		return WRONG;
1435 	if (normalize_overflow(&yourtm.tm_year, &yourtm.tm_mon, MONSPERYEAR))
1436 		return WRONG;
1437 	/*
1438 	** Turn yourtm.tm_year into an actual year number for now.
1439 	** It is converted back to an offset from TM_YEAR_BASE later.
1440 	*/
1441 	if (increment_overflow(&yourtm.tm_year, TM_YEAR_BASE))
1442 		return WRONG;
1443 	while (yourtm.tm_mday <= 0) {
1444 		if (increment_overflow(&yourtm.tm_year, -1))
1445 			return WRONG;
1446 		i = yourtm.tm_year + (1 < yourtm.tm_mon);
1447 		yourtm.tm_mday += year_lengths[isleap(i)];
1448 	}
1449 	while (yourtm.tm_mday > DAYSPERLYEAR) {
1450 		i = yourtm.tm_year + (1 < yourtm.tm_mon);
1451 		yourtm.tm_mday -= year_lengths[isleap(i)];
1452 		if (increment_overflow(&yourtm.tm_year, 1))
1453 			return WRONG;
1454 	}
1455 	for ( ; ; ) {
1456 		i = mon_lengths[isleap(yourtm.tm_year)][yourtm.tm_mon];
1457 		if (yourtm.tm_mday <= i)
1458 			break;
1459 		yourtm.tm_mday -= i;
1460 		if (++yourtm.tm_mon >= MONSPERYEAR) {
1461 			yourtm.tm_mon = 0;
1462 			if (increment_overflow(&yourtm.tm_year, 1))
1463 				return WRONG;
1464 		}
1465 	}
1466 	if (increment_overflow(&yourtm.tm_year, -TM_YEAR_BASE))
1467 		return WRONG;
1468 	if (yourtm.tm_year + TM_YEAR_BASE < EPOCH_YEAR) {
1469 		/*
1470 		** We can't set tm_sec to 0, because that might push the
1471 		** time below the minimum representable time.
1472 		** Set tm_sec to 59 instead.
1473 		** This assumes that the minimum representable time is
1474 		** not in the same minute that a leap second was deleted from,
1475 		** which is a safer assumption than using 58 would be.
1476 		*/
1477 		if (increment_overflow(&yourtm.tm_sec, 1 - SECSPERMIN))
1478 			return WRONG;
1479 		saved_seconds = yourtm.tm_sec;
1480 		yourtm.tm_sec = SECSPERMIN - 1;
1481 	} else {
1482 		saved_seconds = yourtm.tm_sec;
1483 		yourtm.tm_sec = 0;
1484 	}
1485 	/*
1486 	** Divide the search space in half
1487 	** (this works whether time_t is signed or unsigned).
1488 	*/
1489 	bits = TYPE_BIT(time_t) - 1;
1490 	/*
1491 	** If time_t is signed, then 0 is just above the median,
1492 	** assuming two's complement arithmetic.
1493 	** If time_t is unsigned, then (1 << bits) is just above the median.
1494 	*/
1495 	/* LINTED constant in conditional context */
1496 	t = TYPE_SIGNED(time_t) ? 0 : (((time_t) 1) << bits);
1497 	for ( ; ; ) {
1498 		(*funcp)(&t, offset, &mytm);
1499 		dir = tmcomp(&mytm, &yourtm);
1500 		if (dir != 0) {
1501 			if (bits-- < 0)
1502 				return WRONG;
1503 			if (bits < 0)
1504 				--t; /* may be needed if new t is minimal */
1505 			else if (dir > 0)
1506 				t -= ((time_t) 1) << bits;
1507 			else	t += ((time_t) 1) << bits;
1508 			continue;
1509 		}
1510 		if (yourtm.tm_isdst < 0 || mytm.tm_isdst == yourtm.tm_isdst)
1511 			break;
1512 		/*
1513 		** Right time, wrong type.
1514 		** Hunt for right time, right type.
1515 		** It's okay to guess wrong since the guess
1516 		** gets checked.
1517 		*/
1518 		/*
1519 		** The (void *) casts are the benefit of SunOS 3.3 on Sun 2's.
1520 		*/
1521 		sp = (const struct state *)
1522 			(((void *) funcp == (void *) localsub) ?
1523 			lclptr : gmtptr);
1524 #ifdef ALL_STATE
1525 		if (sp == NULL)
1526 			return WRONG;
1527 #endif /* defined ALL_STATE */
1528 		for (i = sp->typecnt - 1; i >= 0; --i) {
1529 			if (sp->ttis[i].tt_isdst != yourtm.tm_isdst)
1530 				continue;
1531 			for (j = sp->typecnt - 1; j >= 0; --j) {
1532 				if (sp->ttis[j].tt_isdst == yourtm.tm_isdst)
1533 					continue;
1534 				newt = t + sp->ttis[j].tt_gmtoff -
1535 					sp->ttis[i].tt_gmtoff;
1536 				(*funcp)(&newt, offset, &mytm);
1537 				if (tmcomp(&mytm, &yourtm) != 0)
1538 					continue;
1539 				if (mytm.tm_isdst != yourtm.tm_isdst)
1540 					continue;
1541 				/*
1542 				** We have a match.
1543 				*/
1544 				t = newt;
1545 				goto label;
1546 			}
1547 		}
1548 		return WRONG;
1549 	}
1550 label:
1551 	newt = t + saved_seconds;
1552 	if ((newt < t) != (saved_seconds < 0))
1553 		return WRONG;
1554 	t = newt;
1555 	(*funcp)(&t, offset, tmp);
1556 	*okayp = TRUE;
1557 	return t;
1558 }
1559 
1560 static time_t
1561 time2(tmp, funcp, offset, okayp)
1562 struct tm * const	tmp;
1563 void (* const		funcp) P((const time_t*, long, struct tm*));
1564 const long		offset;
1565 int * const		okayp;
1566 {
1567 	time_t	t;
1568 
1569 	/*
1570 	** First try without normalization of seconds
1571 	** (in case tm_sec contains a value associated with a leap second).
1572 	** If that fails, try with normalization of seconds.
1573 	*/
1574 	t = time2sub(tmp, funcp, offset, okayp, FALSE);
1575 	return *okayp ? t : time2sub(tmp, funcp, offset, okayp, TRUE);
1576 }
1577 
1578 static time_t
1579 time1(tmp, funcp, offset)
1580 struct tm * const	tmp;
1581 void (* const		funcp) P((const time_t *, long, struct tm *));
1582 const long		offset;
1583 {
1584 	register time_t			t;
1585 	register const struct state *	sp;
1586 	register int			samei, otheri;
1587 	int				okay;
1588 
1589 	if (tmp->tm_isdst > 1)
1590 		tmp->tm_isdst = 1;
1591 	t = time2(tmp, funcp, offset, &okay);
1592 #ifdef PCTS
1593 	/*
1594 	** PCTS code courtesy Grant Sullivan (grant@osf.org).
1595 	*/
1596 	if (okay)
1597 		return t;
1598 	if (tmp->tm_isdst < 0)
1599 		tmp->tm_isdst = 0;	/* reset to std and try again */
1600 #endif /* defined PCTS */
1601 #ifndef PCTS
1602 	if (okay || tmp->tm_isdst < 0)
1603 		return t;
1604 #endif /* !defined PCTS */
1605 	/*
1606 	** We're supposed to assume that somebody took a time of one type
1607 	** and did some math on it that yielded a "struct tm" that's bad.
1608 	** We try to divine the type they started from and adjust to the
1609 	** type they need.
1610 	*/
1611 	/*
1612 	** The (void *) casts are the benefit of SunOS 3.3 on Sun 2's.
1613 	*/
1614 	sp = (const struct state *) (((void *) funcp == (void *) localsub) ?
1615 		lclptr : gmtptr);
1616 #ifdef ALL_STATE
1617 	if (sp == NULL)
1618 		return WRONG;
1619 #endif /* defined ALL_STATE */
1620 	for (samei = sp->typecnt - 1; samei >= 0; --samei) {
1621 		if (sp->ttis[samei].tt_isdst != tmp->tm_isdst)
1622 			continue;
1623 		for (otheri = sp->typecnt - 1; otheri >= 0; --otheri) {
1624 			if (sp->ttis[otheri].tt_isdst == tmp->tm_isdst)
1625 				continue;
1626 			tmp->tm_sec += (int)(sp->ttis[otheri].tt_gmtoff -
1627 					sp->ttis[samei].tt_gmtoff);
1628 			tmp->tm_isdst = !tmp->tm_isdst;
1629 			t = time2(tmp, funcp, offset, &okay);
1630 			if (okay)
1631 				return t;
1632 			tmp->tm_sec -= (int)(sp->ttis[otheri].tt_gmtoff -
1633 					sp->ttis[samei].tt_gmtoff);
1634 			tmp->tm_isdst = !tmp->tm_isdst;
1635 		}
1636 	}
1637 	return WRONG;
1638 }
1639 
1640 time_t
1641 mktime(tmp)
1642 struct tm * const	tmp;
1643 {
1644 	time_t result;
1645 
1646 	rwlock_wrlock(&lcl_lock);
1647 	tzset_unlocked();
1648 	result = time1(tmp, localsub, 0L);
1649 	rwlock_unlock(&lcl_lock);
1650 	return (result);
1651 }
1652 
1653 #ifdef STD_INSPIRED
1654 
1655 time_t
1656 timelocal(tmp)
1657 struct tm * const	tmp;
1658 {
1659 	tmp->tm_isdst = -1;	/* in case it wasn't initialized */
1660 	return mktime(tmp);
1661 }
1662 
1663 time_t
1664 timegm(tmp)
1665 struct tm * const	tmp;
1666 {
1667 	tmp->tm_isdst = 0;
1668 	return time1(tmp, gmtsub, 0L);
1669 }
1670 
1671 time_t
1672 timeoff(tmp, offset)
1673 struct tm * const	tmp;
1674 const long		offset;
1675 {
1676 	tmp->tm_isdst = 0;
1677 	return time1(tmp, gmtsub, offset);
1678 }
1679 
1680 #endif /* defined STD_INSPIRED */
1681 
1682 #ifdef CMUCS
1683 
1684 /*
1685 ** The following is supplied for compatibility with
1686 ** previous versions of the CMUCS runtime library.
1687 */
1688 
1689 long
1690 gtime(tmp)
1691 struct tm * const	tmp;
1692 {
1693 	const time_t	t = mktime(tmp);
1694 
1695 	if (t == WRONG)
1696 		return -1;
1697 	return t;
1698 }
1699 
1700 #endif /* defined CMUCS */
1701 
1702 /*
1703 ** XXX--is the below the right way to conditionalize??
1704 */
1705 
1706 #ifdef STD_INSPIRED
1707 
1708 /*
1709 ** IEEE Std 1003.1-1988 (POSIX) legislates that 536457599
1710 ** shall correspond to "Wed Dec 31 23:59:59 UTC 1986", which
1711 ** is not the case if we are accounting for leap seconds.
1712 ** So, we provide the following conversion routines for use
1713 ** when exchanging timestamps with POSIX conforming systems.
1714 */
1715 
1716 static long
1717 leapcorr(timep)
1718 time_t *	timep;
1719 {
1720 	register struct state *		sp;
1721 	register struct lsinfo *	lp;
1722 	register int			i;
1723 
1724 	sp = lclptr;
1725 	i = sp->leapcnt;
1726 	while (--i >= 0) {
1727 		lp = &sp->lsis[i];
1728 		if (*timep >= lp->ls_trans)
1729 			return lp->ls_corr;
1730 	}
1731 	return 0;
1732 }
1733 
1734 time_t
1735 time2posix(t)
1736 time_t	t;
1737 {
1738 	time_t result;
1739 
1740 	rwlock_wrlock(&lcl_lock);
1741 	tzset_unlocked();
1742 	result = t - leapcorr(&t);
1743 	rwlock_unlock(&lcl_lock);
1744 	return (result);
1745 }
1746 
1747 time_t
1748 posix2time(t)
1749 time_t	t;
1750 {
1751 	time_t	x;
1752 	time_t	y;
1753 
1754 	rwlock_wrlock(&lcl_lock);
1755 	tzset_unlocked();
1756 	/*
1757 	** For a positive leap second hit, the result
1758 	** is not unique.  For a negative leap second
1759 	** hit, the corresponding time doesn't exist,
1760 	** so we return an adjacent second.
1761 	*/
1762 	x = t + leapcorr(&t);
1763 	y = x - leapcorr(&x);
1764 	if (y < t) {
1765 		do {
1766 			x++;
1767 			y = x - leapcorr(&x);
1768 		} while (y < t);
1769 		if (t != y) {
1770 			rwlock_unlock(&lcl_lock);
1771 			return x - 1;
1772 		}
1773 	} else if (y > t) {
1774 		do {
1775 			--x;
1776 			y = x - leapcorr(&x);
1777 		} while (y > t);
1778 		if (t != y) {
1779 			rwlock_unlock(&lcl_lock);
1780 			return x + 1;
1781 		}
1782 	}
1783 	rwlock_unlock(&lcl_lock);
1784 	return x;
1785 }
1786 
1787 #endif /* defined STD_INSPIRED */
1788