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1 /*
2 ** This file is in the public domain, so clarified as of
3 ** 1996-06-05 by Arthur David Olson (arthur_david_olson@nih.gov).
4 */
5
6 #include <sys/cdefs.h>
7 #ifndef lint
8 #ifndef NOID
9 static char elsieid[] __unused = "@(#)localtime.c 7.78";
10 #endif /* !defined NOID */
11 #endif /* !defined lint */
12 __FBSDID("$FreeBSD: src/lib/libc/stdtime/localtime.c,v 1.43 2008/04/01 06:56:11 davidxu Exp $");
13
14 /*
15 ** Leap second handling from Bradley White (bww@k.gp.cs.cmu.edu).
16 ** POSIX-style TZ environment variable handling from Guy Harris
17 ** (guy@auspex.com).
18 */
19
20 /*LINTLIBRARY*/
21
22 #include "namespace.h"
23 #include <sys/types.h>
24 #include <sys/stat.h>
25 #include <fcntl.h>
26 #include <pthread.h>
27 #include "private.h"
28 #include "un-namespace.h"
29
30 #include "tzfile.h"
31
32 #include "libc_private.h"
33
34 #define _MUTEX_LOCK(x) if (__isthreaded) _pthread_mutex_lock(x)
35 #define _MUTEX_UNLOCK(x) if (__isthreaded) _pthread_mutex_unlock(x)
36
37 #define _RWLOCK_RDLOCK(x) \
38 do { \
39 if (__isthreaded) _pthread_rwlock_rdlock(x); \
40 } while (0)
41
42 #define _RWLOCK_WRLOCK(x) \
43 do { \
44 if (__isthreaded) _pthread_rwlock_wrlock(x); \
45 } while (0)
46
47 #define _RWLOCK_UNLOCK(x) \
48 do { \
49 if (__isthreaded) _pthread_rwlock_unlock(x); \
50 } while (0)
51
52 /*
53 ** SunOS 4.1.1 headers lack O_BINARY.
54 */
55
56 #ifdef O_BINARY
57 #define OPEN_MODE (O_RDONLY | O_BINARY)
58 #endif /* defined O_BINARY */
59 #ifndef O_BINARY
60 #define OPEN_MODE O_RDONLY
61 #endif /* !defined O_BINARY */
62
63 #ifndef WILDABBR
64 /*
65 ** Someone might make incorrect use of a time zone abbreviation:
66 ** 1. They might reference tzname[0] before calling tzset (explicitly
67 ** or implicitly).
68 ** 2. They might reference tzname[1] before calling tzset (explicitly
69 ** or implicitly).
70 ** 3. They might reference tzname[1] after setting to a time zone
71 ** in which Daylight Saving Time is never observed.
72 ** 4. They might reference tzname[0] after setting to a time zone
73 ** in which Standard Time is never observed.
74 ** 5. They might reference tm.TM_ZONE after calling offtime.
75 ** What's best to do in the above cases is open to debate;
76 ** for now, we just set things up so that in any of the five cases
77 ** WILDABBR is used. Another possibility: initialize tzname[0] to the
78 ** string "tzname[0] used before set", and similarly for the other cases.
79 ** And another: initialize tzname[0] to "ERA", with an explanation in the
80 ** manual page of what this "time zone abbreviation" means (doing this so
81 ** that tzname[0] has the "normal" length of three characters).
82 */
83 #define WILDABBR " "
84 #endif /* !defined WILDABBR */
85
86 static char wildabbr[] = "WILDABBR";
87
88 /*
89 * In June 2004 it was decided UTC was a more appropriate default time
90 * zone than GMT.
91 */
92
93 static const char gmt[] = "UTC";
94
95 /*
96 ** The DST rules to use if TZ has no rules and we can't load TZDEFRULES.
97 ** We default to US rules as of 1999-08-17.
98 ** POSIX 1003.1 section 8.1.1 says that the default DST rules are
99 ** implementation dependent; for historical reasons, US rules are a
100 ** common default.
101 */
102 #ifndef TZDEFRULESTRING
103 #define TZDEFRULESTRING ",M4.1.0,M10.5.0"
104 #endif /* !defined TZDEFDST */
105
106 struct ttinfo { /* time type information */
107 long tt_gmtoff; /* UTC offset in seconds */
108 int tt_isdst; /* used to set tm_isdst */
109 int tt_abbrind; /* abbreviation list index */
110 int tt_ttisstd; /* TRUE if transition is std time */
111 int tt_ttisgmt; /* TRUE if transition is UTC */
112 };
113
114 struct lsinfo { /* leap second information */
115 time_t ls_trans; /* transition time */
116 long ls_corr; /* correction to apply */
117 };
118
119 #define BIGGEST(a, b) (((a) > (b)) ? (a) : (b))
120
121 #ifdef TZNAME_MAX
122 #define MY_TZNAME_MAX TZNAME_MAX
123 #endif /* defined TZNAME_MAX */
124 #ifndef TZNAME_MAX
125 #define MY_TZNAME_MAX 255
126 #endif /* !defined TZNAME_MAX */
127
128 struct state {
129 int leapcnt;
130 int timecnt;
131 int typecnt;
132 int charcnt;
133 time_t ats[TZ_MAX_TIMES];
134 unsigned char types[TZ_MAX_TIMES];
135 struct ttinfo ttis[TZ_MAX_TYPES];
136 char chars[BIGGEST(BIGGEST(TZ_MAX_CHARS + 1, sizeof gmt),
137 (2 * (MY_TZNAME_MAX + 1)))];
138 struct lsinfo lsis[TZ_MAX_LEAPS];
139 };
140
141 struct rule {
142 int r_type; /* type of rule--see below */
143 int r_day; /* day number of rule */
144 int r_week; /* week number of rule */
145 int r_mon; /* month number of rule */
146 long r_time; /* transition time of rule */
147 };
148
149 #define JULIAN_DAY 0 /* Jn - Julian day */
150 #define DAY_OF_YEAR 1 /* n - day of year */
151 #define MONTH_NTH_DAY_OF_WEEK 2 /* Mm.n.d - month, week, day of week */
152
153 /*
154 ** Prototypes for static functions.
155 */
156
157 static long detzcode(const char * codep);
158 static const char * getzname(const char * strp);
159 static const char * getnum(const char * strp, int * nump, int min,
160 int max);
161 static const char * getsecs(const char * strp, long * secsp);
162 static const char * getoffset(const char * strp, long * offsetp);
163 static const char * getrule(const char * strp, struct rule * rulep);
164 static void gmtload(struct state * sp);
165 static void gmtsub(const time_t * timep, long offset,
166 struct tm * tmp);
167 static void localsub(const time_t * timep, long offset,
168 struct tm * tmp);
169 static int increment_overflow(int * number, int delta);
170 static int normalize_overflow(int * tensptr, int * unitsptr,
171 int base);
172 static void settzname(void);
173 static time_t time1(struct tm * tmp,
174 void(*funcp) (const time_t *,
175 long, struct tm *),
176 long offset);
177 static time_t time2(struct tm *tmp,
178 void(*funcp) (const time_t *,
179 long, struct tm*),
180 long offset, int * okayp);
181 static time_t time2sub(struct tm *tmp,
182 void(*funcp) (const time_t *,
183 long, struct tm*),
184 long offset, int * okayp, int do_norm_secs);
185 static void timesub(const time_t * timep, long offset,
186 const struct state * sp, struct tm * tmp);
187 static int tmcomp(const struct tm * atmp,
188 const struct tm * btmp);
189 static time_t transtime(time_t janfirst, int year,
190 const struct rule * rulep, long offset);
191 static int tzload(const char * name, struct state * sp);
192 static int tzparse(const char * name, struct state * sp,
193 int lastditch);
194
195 #ifdef ALL_STATE
196 static struct state * lclptr;
197 static struct state * gmtptr;
198 #endif /* defined ALL_STATE */
199
200 #ifndef ALL_STATE
201 static struct state lclmem;
202 static struct state gmtmem;
203 #define lclptr (&lclmem)
204 #define gmtptr (&gmtmem)
205 #endif /* State Farm */
206
207 #ifndef TZ_STRLEN_MAX
208 #define TZ_STRLEN_MAX 255
209 #endif /* !defined TZ_STRLEN_MAX */
210
211 static char lcl_TZname[TZ_STRLEN_MAX + 1];
212 static int lcl_is_set;
213 static int gmt_is_set;
214 static pthread_rwlock_t lcl_rwlock = PTHREAD_RWLOCK_INITIALIZER;
215 static pthread_mutex_t gmt_mutex = PTHREAD_MUTEX_INITIALIZER;
216
217 char * tzname[2] = {
218 wildabbr,
219 wildabbr
220 };
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 long result;
246 int i;
247
248 result = (codep[0] & 0x80) ? ~0L : 0L;
249 for (i = 0; i < 4; ++i)
250 result = (result << 8) | (codep[i] & 0xff);
251 return result;
252 }
253
254 static void
255 settzname(void)
256 {
257 struct state * sp = lclptr;
258 int i;
259
260 tzname[0] = wildabbr;
261 tzname[1] = wildabbr;
262 #ifdef USG_COMPAT
263 daylight = 0;
264 timezone = 0;
265 #endif /* defined USG_COMPAT */
266 #ifdef ALTZONE
267 altzone = 0;
268 #endif /* defined ALTZONE */
269 #ifdef ALL_STATE
270 if (sp == NULL) {
271 tzname[0] = tzname[1] = gmt;
272 return;
273 }
274 #endif /* defined ALL_STATE */
275 for (i = 0; i < sp->typecnt; ++i) {
276 const struct ttinfo * const ttisp = &sp->ttis[i];
277
278 tzname[ttisp->tt_isdst] =
279 &sp->chars[ttisp->tt_abbrind];
280 #ifdef USG_COMPAT
281 if (ttisp->tt_isdst)
282 daylight = 1;
283 if (i == 0 || !ttisp->tt_isdst)
284 timezone = -(ttisp->tt_gmtoff);
285 #endif /* defined USG_COMPAT */
286 #ifdef ALTZONE
287 if (i == 0 || ttisp->tt_isdst)
288 altzone = -(ttisp->tt_gmtoff);
289 #endif /* defined ALTZONE */
290 }
291 /*
292 ** And to get the latest zone names into tzname. . .
293 */
294 for (i = 0; i < sp->timecnt; ++i) {
295 const struct ttinfo * const ttisp =
296 &sp->ttis[
297 sp->types[i]];
298
299 tzname[ttisp->tt_isdst] =
300 &sp->chars[ttisp->tt_abbrind];
301 }
302 }
303
304 static int
305 tzload(name, sp)
306 const char * name;
307 struct state * const sp;
308 {
309 const char * p;
310 int i;
311 int fid;
312
313 /* XXX The following is from OpenBSD, and I'm not sure it is correct */
314 if (name != NULL && issetugid() != 0)
315 if ((name[0] == ':' && name[1] == '/') ||
316 name[0] == '/' || strchr(name, '.'))
317 name = NULL;
318 if (name == NULL && (name = TZDEFAULT) == NULL)
319 return -1;
320 {
321 int doaccess;
322 struct stat stab;
323 /*
324 ** Section 4.9.1 of the C standard says that
325 ** "FILENAME_MAX expands to an integral constant expression
326 ** that is the size needed for an array of char large enough
327 ** to hold the longest file name string that the implementation
328 ** guarantees can be opened."
329 */
330 char fullname[FILENAME_MAX + 1];
331
332 if (name[0] == ':')
333 ++name;
334 doaccess = name[0] == '/';
335 if (!doaccess) {
336 if ((p = TZDIR) == NULL)
337 return -1;
338 if ((strlen(p) + 1 + strlen(name) + 1) >= sizeof fullname)
339 return -1;
340 (void) strcpy(fullname, p);
341 (void) strcat(fullname, "/");
342 (void) strcat(fullname, name);
343 /*
344 ** Set doaccess if '.' (as in "../") shows up in name.
345 */
346 if (strchr(name, '.') != NULL)
347 doaccess = TRUE;
348 name = fullname;
349 }
350 if (doaccess && access(name, R_OK) != 0)
351 return -1;
352 if ((fid = _open(name, OPEN_MODE)) == -1)
353 return -1;
354 if ((_fstat(fid, &stab) < 0) || !S_ISREG(stab.st_mode)) {
355 _close(fid);
356 return -1;
357 }
358 }
359 {
360 struct tzhead * tzhp;
361 union {
362 struct tzhead tzhead;
363 char buf[sizeof *sp + sizeof *tzhp];
364 } u;
365 int ttisstdcnt;
366 int ttisgmtcnt;
367
368 i = _read(fid, u.buf, sizeof u.buf);
369 if (_close(fid) != 0)
370 return -1;
371 ttisstdcnt = (int) detzcode(u.tzhead.tzh_ttisstdcnt);
372 ttisgmtcnt = (int) detzcode(u.tzhead.tzh_ttisgmtcnt);
373 sp->leapcnt = (int) detzcode(u.tzhead.tzh_leapcnt);
374 sp->timecnt = (int) detzcode(u.tzhead.tzh_timecnt);
375 sp->typecnt = (int) detzcode(u.tzhead.tzh_typecnt);
376 sp->charcnt = (int) detzcode(u.tzhead.tzh_charcnt);
377 p = u.tzhead.tzh_charcnt + sizeof u.tzhead.tzh_charcnt;
378 if (sp->leapcnt < 0 || sp->leapcnt > TZ_MAX_LEAPS ||
379 sp->typecnt <= 0 || sp->typecnt > TZ_MAX_TYPES ||
380 sp->timecnt < 0 || sp->timecnt > TZ_MAX_TIMES ||
381 sp->charcnt < 0 || sp->charcnt > TZ_MAX_CHARS ||
382 (ttisstdcnt != sp->typecnt && ttisstdcnt != 0) ||
383 (ttisgmtcnt != sp->typecnt && ttisgmtcnt != 0))
384 return -1;
385 if (i - (p - u.buf) < sp->timecnt * 4 + /* ats */
386 sp->timecnt + /* types */
387 sp->typecnt * (4 + 2) + /* ttinfos */
388 sp->charcnt + /* chars */
389 sp->leapcnt * (4 + 4) + /* lsinfos */
390 ttisstdcnt + /* ttisstds */
391 ttisgmtcnt) /* ttisgmts */
392 return -1;
393 for (i = 0; i < sp->timecnt; ++i) {
394 sp->ats[i] = detzcode(p);
395 p += 4;
396 }
397 for (i = 0; i < sp->timecnt; ++i) {
398 sp->types[i] = (unsigned char) *p++;
399 if (sp->types[i] >= sp->typecnt)
400 return -1;
401 }
402 for (i = 0; i < sp->typecnt; ++i) {
403 struct ttinfo * ttisp;
404
405 ttisp = &sp->ttis[i];
406 ttisp->tt_gmtoff = detzcode(p);
407 p += 4;
408 ttisp->tt_isdst = (unsigned char) *p++;
409 if (ttisp->tt_isdst != 0 && ttisp->tt_isdst != 1)
410 return -1;
411 ttisp->tt_abbrind = (unsigned char) *p++;
412 if (ttisp->tt_abbrind < 0 ||
413 ttisp->tt_abbrind > sp->charcnt)
414 return -1;
415 }
416 for (i = 0; i < sp->charcnt; ++i)
417 sp->chars[i] = *p++;
418 sp->chars[i] = '\0'; /* ensure '\0' at end */
419 for (i = 0; i < sp->leapcnt; ++i) {
420 struct lsinfo * lsisp;
421
422 lsisp = &sp->lsis[i];
423 lsisp->ls_trans = detzcode(p);
424 p += 4;
425 lsisp->ls_corr = detzcode(p);
426 p += 4;
427 }
428 for (i = 0; i < sp->typecnt; ++i) {
429 struct ttinfo * ttisp;
430
431 ttisp = &sp->ttis[i];
432 if (ttisstdcnt == 0)
433 ttisp->tt_ttisstd = FALSE;
434 else {
435 ttisp->tt_ttisstd = *p++;
436 if (ttisp->tt_ttisstd != TRUE &&
437 ttisp->tt_ttisstd != FALSE)
438 return -1;
439 }
440 }
441 for (i = 0; i < sp->typecnt; ++i) {
442 struct ttinfo * ttisp;
443
444 ttisp = &sp->ttis[i];
445 if (ttisgmtcnt == 0)
446 ttisp->tt_ttisgmt = FALSE;
447 else {
448 ttisp->tt_ttisgmt = *p++;
449 if (ttisp->tt_ttisgmt != TRUE &&
450 ttisp->tt_ttisgmt != FALSE)
451 return -1;
452 }
453 }
454 }
455 return 0;
456 }
457
458 static const int mon_lengths[2][MONSPERYEAR] = {
459 { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 },
460 { 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }
461 };
462
463 static const int year_lengths[2] = {
464 DAYSPERNYEAR, DAYSPERLYEAR
465 };
466
467 /*
468 ** Given a pointer into a time zone string, scan until a character that is not
469 ** a valid character in a zone name is found. Return a pointer to that
470 ** character.
471 */
472
473 static const char *
474 getzname(strp)
475 const char * strp;
476 {
477 char c;
478
479 while ((c = *strp) != '\0' && !is_digit(c) && c != ',' && c != '-' &&
480 c != '+')
481 ++strp;
482 return strp;
483 }
484
485 /*
486 ** Given a pointer into a time zone string, extract a number from that string.
487 ** Check that the number is within a specified range; if it is not, return
488 ** NULL.
489 ** Otherwise, return a pointer to the first character not part of the number.
490 */
491
492 static const char *
493 getnum(strp, nump, min, max)
494 const char * strp;
495 int * const nump;
496 const int min;
497 const int max;
498 {
499 char c;
500 int num;
501
502 if (strp == NULL || !is_digit(c = *strp))
503 return NULL;
504 num = 0;
505 do {
506 num = num * 10 + (c - '0');
507 if (num > max)
508 return NULL; /* illegal value */
509 c = *++strp;
510 } while (is_digit(c));
511 if (num < min)
512 return NULL; /* illegal value */
513 *nump = num;
514 return strp;
515 }
516
517 /*
518 ** Given a pointer into a time zone string, extract a number of seconds,
519 ** in hh[:mm[:ss]] form, from the string.
520 ** If any error occurs, return NULL.
521 ** Otherwise, return a pointer to the first character not part of the number
522 ** of seconds.
523 */
524
525 static const char *
526 getsecs(strp, secsp)
527 const char * strp;
528 long * const secsp;
529 {
530 int num;
531
532 /*
533 ** `HOURSPERDAY * DAYSPERWEEK - 1' allows quasi-Posix rules like
534 ** "M10.4.6/26", which does not conform to Posix,
535 ** but which specifies the equivalent of
536 ** ``02:00 on the first Sunday on or after 23 Oct''.
537 */
538 strp = getnum(strp, &num, 0, HOURSPERDAY * DAYSPERWEEK - 1);
539 if (strp == NULL)
540 return NULL;
541 *secsp = num * (long) SECSPERHOUR;
542 if (*strp == ':') {
543 ++strp;
544 strp = getnum(strp, &num, 0, MINSPERHOUR - 1);
545 if (strp == NULL)
546 return NULL;
547 *secsp += num * SECSPERMIN;
548 if (*strp == ':') {
549 ++strp;
550 /* `SECSPERMIN' allows for leap seconds. */
551 strp = getnum(strp, &num, 0, SECSPERMIN);
552 if (strp == NULL)
553 return NULL;
554 *secsp += num;
555 }
556 }
557 return strp;
558 }
559
560 /*
561 ** Given a pointer into a time zone string, extract an offset, in
562 ** [+-]hh[:mm[:ss]] form, from the string.
563 ** If any error occurs, return NULL.
564 ** Otherwise, return a pointer to the first character not part of the time.
565 */
566
567 static const char *
568 getoffset(strp, offsetp)
569 const char * strp;
570 long * const offsetp;
571 {
572 int neg = 0;
573
574 if (*strp == '-') {
575 neg = 1;
576 ++strp;
577 } else if (*strp == '+')
578 ++strp;
579 strp = getsecs(strp, offsetp);
580 if (strp == NULL)
581 return NULL; /* illegal time */
582 if (neg)
583 *offsetp = -*offsetp;
584 return strp;
585 }
586
587 /*
588 ** Given a pointer into a time zone string, extract a rule in the form
589 ** date[/time]. See POSIX section 8 for the format of "date" and "time".
590 ** If a valid rule is not found, return NULL.
591 ** Otherwise, return a pointer to the first character not part of the rule.
592 */
593
594 static const char *
595 getrule(strp, rulep)
596 const char * strp;
597 struct rule * const rulep;
598 {
599 if (*strp == 'J') {
600 /*
601 ** Julian day.
602 */
603 rulep->r_type = JULIAN_DAY;
604 ++strp;
605 strp = getnum(strp, &rulep->r_day, 1, DAYSPERNYEAR);
606 } else if (*strp == 'M') {
607 /*
608 ** Month, week, day.
609 */
610 rulep->r_type = MONTH_NTH_DAY_OF_WEEK;
611 ++strp;
612 strp = getnum(strp, &rulep->r_mon, 1, MONSPERYEAR);
613 if (strp == NULL)
614 return NULL;
615 if (*strp++ != '.')
616 return NULL;
617 strp = getnum(strp, &rulep->r_week, 1, 5);
618 if (strp == NULL)
619 return NULL;
620 if (*strp++ != '.')
621 return NULL;
622 strp = getnum(strp, &rulep->r_day, 0, DAYSPERWEEK - 1);
623 } else if (is_digit(*strp)) {
624 /*
625 ** Day of year.
626 */
627 rulep->r_type = DAY_OF_YEAR;
628 strp = getnum(strp, &rulep->r_day, 0, DAYSPERLYEAR - 1);
629 } else return NULL; /* invalid format */
630 if (strp == NULL)
631 return NULL;
632 if (*strp == '/') {
633 /*
634 ** Time specified.
635 */
636 ++strp;
637 strp = getsecs(strp, &rulep->r_time);
638 } else rulep->r_time = 2 * SECSPERHOUR; /* default = 2:00:00 */
639 return strp;
640 }
641
642 /*
643 ** Given the Epoch-relative time of January 1, 00:00:00 UTC, in a year, the
644 ** year, a rule, and the offset from UTC at the time that rule takes effect,
645 ** calculate the Epoch-relative time that rule takes effect.
646 */
647
648 static time_t
649 transtime(janfirst, year, rulep, offset)
650 const time_t janfirst;
651 const int year;
652 const struct rule * const rulep;
653 const long offset;
654 {
655 int leapyear;
656 time_t value;
657 int i;
658 int d, m1, yy0, yy1, yy2, dow;
659
660 INITIALIZE(value);
661 leapyear = isleap(year);
662 switch (rulep->r_type) {
663
664 case JULIAN_DAY:
665 /*
666 ** Jn - Julian day, 1 == January 1, 60 == March 1 even in leap
667 ** years.
668 ** In non-leap years, or if the day number is 59 or less, just
669 ** add SECSPERDAY times the day number-1 to the time of
670 ** January 1, midnight, to get the day.
671 */
672 value = janfirst + (rulep->r_day - 1) * SECSPERDAY;
673 if (leapyear && rulep->r_day >= 60)
674 value += SECSPERDAY;
675 break;
676
677 case DAY_OF_YEAR:
678 /*
679 ** n - day of year.
680 ** Just add SECSPERDAY times the day number to the time of
681 ** January 1, midnight, to get the day.
682 */
683 value = janfirst + rulep->r_day * SECSPERDAY;
684 break;
685
686 case MONTH_NTH_DAY_OF_WEEK:
687 /*
688 ** Mm.n.d - nth "dth day" of month m.
689 */
690 value = janfirst;
691 for (i = 0; i < rulep->r_mon - 1; ++i)
692 value += mon_lengths[leapyear][i] * SECSPERDAY;
693
694 /*
695 ** Use Zeller's Congruence to get day-of-week of first day of
696 ** month.
697 */
698 m1 = (rulep->r_mon + 9) % 12 + 1;
699 yy0 = (rulep->r_mon <= 2) ? (year - 1) : year;
700 yy1 = yy0 / 100;
701 yy2 = yy0 % 100;
702 dow = ((26 * m1 - 2) / 10 +
703 1 + yy2 + yy2 / 4 + yy1 / 4 - 2 * yy1) % 7;
704 if (dow < 0)
705 dow += DAYSPERWEEK;
706
707 /*
708 ** "dow" is the day-of-week of the first day of the month. Get
709 ** the day-of-month (zero-origin) of the first "dow" day of the
710 ** month.
711 */
712 d = rulep->r_day - dow;
713 if (d < 0)
714 d += DAYSPERWEEK;
715 for (i = 1; i < rulep->r_week; ++i) {
716 if (d + DAYSPERWEEK >=
717 mon_lengths[leapyear][rulep->r_mon - 1])
718 break;
719 d += DAYSPERWEEK;
720 }
721
722 /*
723 ** "d" is the day-of-month (zero-origin) of the day we want.
724 */
725 value += d * SECSPERDAY;
726 break;
727 }
728
729 /*
730 ** "value" is the Epoch-relative time of 00:00:00 UTC on the day in
731 ** question. To get the Epoch-relative time of the specified local
732 ** time on that day, add the transition time and the current offset
733 ** from UTC.
734 */
735 return value + rulep->r_time + offset;
736 }
737
738 /*
739 ** Given a POSIX section 8-style TZ string, fill in the rule tables as
740 ** appropriate.
741 */
742
743 static int
744 tzparse(name, sp, lastditch)
745 const char * name;
746 struct state * const sp;
747 const int lastditch;
748 {
749 const char * stdname;
750 const char * dstname;
751 size_t stdlen;
752 size_t dstlen;
753 long stdoffset;
754 long dstoffset;
755 time_t * atp;
756 unsigned char * typep;
757 char * cp;
758 int load_result;
759
760 INITIALIZE(dstname);
761 stdname = name;
762 if (lastditch) {
763 stdlen = strlen(name); /* length of standard zone name */
764 name += stdlen;
765 if (stdlen >= sizeof sp->chars)
766 stdlen = (sizeof sp->chars) - 1;
767 stdoffset = 0;
768 } else {
769 name = getzname(name);
770 stdlen = name - stdname;
771 if (stdlen < 3)
772 return -1;
773 if (*name == '\0')
774 return -1; /* was "stdoffset = 0;" */
775 else {
776 name = getoffset(name, &stdoffset);
777 if (name == NULL)
778 return -1;
779 }
780 }
781 load_result = tzload(TZDEFRULES, sp);
782 if (load_result != 0)
783 sp->leapcnt = 0; /* so, we're off a little */
784 if (*name != '\0') {
785 dstname = name;
786 name = getzname(name);
787 dstlen = name - dstname; /* length of DST zone name */
788 if (dstlen < 3)
789 return -1;
790 if (*name != '\0' && *name != ',' && *name != ';') {
791 name = getoffset(name, &dstoffset);
792 if (name == NULL)
793 return -1;
794 } else dstoffset = stdoffset - SECSPERHOUR;
795 if (*name == '\0' && load_result != 0)
796 name = TZDEFRULESTRING;
797 if (*name == ',' || *name == ';') {
798 struct rule start;
799 struct rule end;
800 int year;
801 time_t janfirst;
802 time_t starttime;
803 time_t endtime;
804
805 ++name;
806 if ((name = getrule(name, &start)) == NULL)
807 return -1;
808 if (*name++ != ',')
809 return -1;
810 if ((name = getrule(name, &end)) == NULL)
811 return -1;
812 if (*name != '\0')
813 return -1;
814 sp->typecnt = 2; /* standard time and DST */
815 /*
816 ** Two transitions per year, from EPOCH_YEAR to 2037.
817 */
818 sp->timecnt = 2 * (2037 - EPOCH_YEAR + 1);
819 if (sp->timecnt > TZ_MAX_TIMES)
820 return -1;
821 sp->ttis[0].tt_gmtoff = -dstoffset;
822 sp->ttis[0].tt_isdst = 1;
823 sp->ttis[0].tt_abbrind = stdlen + 1;
824 sp->ttis[1].tt_gmtoff = -stdoffset;
825 sp->ttis[1].tt_isdst = 0;
826 sp->ttis[1].tt_abbrind = 0;
827 atp = sp->ats;
828 typep = sp->types;
829 janfirst = 0;
830 for (year = EPOCH_YEAR; year <= 2037; ++year) {
831 starttime = transtime(janfirst, year, &start,
832 stdoffset);
833 endtime = transtime(janfirst, year, &end,
834 dstoffset);
835 if (starttime > endtime) {
836 *atp++ = endtime;
837 *typep++ = 1; /* DST ends */
838 *atp++ = starttime;
839 *typep++ = 0; /* DST begins */
840 } else {
841 *atp++ = starttime;
842 *typep++ = 0; /* DST begins */
843 *atp++ = endtime;
844 *typep++ = 1; /* DST ends */
845 }
846 janfirst += year_lengths[isleap(year)] *
847 SECSPERDAY;
848 }
849 } else {
850 long theirstdoffset;
851 long theirdstoffset;
852 long theiroffset;
853 int isdst;
854 int i;
855 int j;
856
857 if (*name != '\0')
858 return -1;
859 /*
860 ** Initial values of theirstdoffset and theirdstoffset.
861 */
862 theirstdoffset = 0;
863 for (i = 0; i < sp->timecnt; ++i) {
864 j = sp->types[i];
865 if (!sp->ttis[j].tt_isdst) {
866 theirstdoffset =
867 -sp->ttis[j].tt_gmtoff;
868 break;
869 }
870 }
871 theirdstoffset = 0;
872 for (i = 0; i < sp->timecnt; ++i) {
873 j = sp->types[i];
874 if (sp->ttis[j].tt_isdst) {
875 theirdstoffset =
876 -sp->ttis[j].tt_gmtoff;
877 break;
878 }
879 }
880 /*
881 ** Initially we're assumed to be in standard time.
882 */
883 isdst = FALSE;
884 theiroffset = theirstdoffset;
885 /*
886 ** Now juggle transition times and types
887 ** tracking offsets as you do.
888 */
889 for (i = 0; i < sp->timecnt; ++i) {
890 j = sp->types[i];
891 sp->types[i] = sp->ttis[j].tt_isdst;
892 if (sp->ttis[j].tt_ttisgmt) {
893 /* No adjustment to transition time */
894 } else {
895 /*
896 ** If summer time is in effect, and the
897 ** transition time was not specified as
898 ** standard time, add the summer time
899 ** offset to the transition time;
900 ** otherwise, add the standard time
901 ** offset to the transition time.
902 */
903 /*
904 ** Transitions from DST to DDST
905 ** will effectively disappear since
906 ** POSIX provides for only one DST
907 ** offset.
908 */
909 if (isdst && !sp->ttis[j].tt_ttisstd) {
910 sp->ats[i] += dstoffset -
911 theirdstoffset;
912 } else {
913 sp->ats[i] += stdoffset -
914 theirstdoffset;
915 }
916 }
917 theiroffset = -sp->ttis[j].tt_gmtoff;
918 if (sp->ttis[j].tt_isdst)
919 theirdstoffset = theiroffset;
920 else theirstdoffset = theiroffset;
921 }
922 /*
923 ** Finally, fill in ttis.
924 ** ttisstd and ttisgmt need not be handled.
925 */
926 sp->ttis[0].tt_gmtoff = -stdoffset;
927 sp->ttis[0].tt_isdst = FALSE;
928 sp->ttis[0].tt_abbrind = 0;
929 sp->ttis[1].tt_gmtoff = -dstoffset;
930 sp->ttis[1].tt_isdst = TRUE;
931 sp->ttis[1].tt_abbrind = stdlen + 1;
932 sp->typecnt = 2;
933 }
934 } else {
935 dstlen = 0;
936 sp->typecnt = 1; /* only standard time */
937 sp->timecnt = 0;
938 sp->ttis[0].tt_gmtoff = -stdoffset;
939 sp->ttis[0].tt_isdst = 0;
940 sp->ttis[0].tt_abbrind = 0;
941 }
942 sp->charcnt = stdlen + 1;
943 if (dstlen != 0)
944 sp->charcnt += dstlen + 1;
945 if ((size_t) sp->charcnt > sizeof sp->chars)
946 return -1;
947 cp = sp->chars;
948 (void) strncpy(cp, stdname, stdlen);
949 cp += stdlen;
950 *cp++ = '\0';
951 if (dstlen != 0) {
952 (void) strncpy(cp, dstname, dstlen);
953 *(cp + dstlen) = '\0';
954 }
955 return 0;
956 }
957
958 static void
959 gmtload(sp)
960 struct state * const sp;
961 {
962 if (tzload(gmt, sp) != 0)
963 (void) tzparse(gmt, sp, TRUE);
964 }
965
966 static void
967 tzsetwall_basic(int rdlocked)
968 {
969 if (!rdlocked)
970 _RWLOCK_RDLOCK(&lcl_rwlock);
971 if (lcl_is_set < 0) {
972 if (!rdlocked)
973 _RWLOCK_UNLOCK(&lcl_rwlock);
974 return;
975 }
976 _RWLOCK_UNLOCK(&lcl_rwlock);
977
978 _RWLOCK_WRLOCK(&lcl_rwlock);
979 lcl_is_set = -1;
980
981 #ifdef ALL_STATE
982 if (lclptr == NULL) {
983 lclptr = (struct state *) malloc(sizeof *lclptr);
984 if (lclptr == NULL) {
985 settzname(); /* all we can do */
986 _RWLOCK_UNLOCK(&lcl_rwlock);
987 if (rdlocked)
988 _RWLOCK_RDLOCK(&lcl_rwlock);
989 return;
990 }
991 }
992 #endif /* defined ALL_STATE */
993 if (tzload((char *) NULL, lclptr) != 0)
994 gmtload(lclptr);
995 settzname();
996 _RWLOCK_UNLOCK(&lcl_rwlock);
997
998 if (rdlocked)
999 _RWLOCK_RDLOCK(&lcl_rwlock);
1000 }
1001
1002 void
1003 tzsetwall(void)
1004 {
1005 tzsetwall_basic(0);
1006 }
1007
1008 static void
1009 tzset_basic(int rdlocked)
1010 {
1011 const char * name;
1012
1013 name = getenv("TZ");
1014 if (name == NULL) {
1015 tzsetwall_basic(rdlocked);
1016 return;
1017 }
1018
1019 if (!rdlocked)
1020 _RWLOCK_RDLOCK(&lcl_rwlock);
1021 if (lcl_is_set > 0 && strcmp(lcl_TZname, name) == 0) {
1022 if (!rdlocked)
1023 _RWLOCK_UNLOCK(&lcl_rwlock);
1024 return;
1025 }
1026 _RWLOCK_UNLOCK(&lcl_rwlock);
1027
1028 _RWLOCK_WRLOCK(&lcl_rwlock);
1029 lcl_is_set = strlen(name) < sizeof lcl_TZname;
1030 if (lcl_is_set)
1031 (void) strcpy(lcl_TZname, name);
1032
1033 #ifdef ALL_STATE
1034 if (lclptr == NULL) {
1035 lclptr = (struct state *) malloc(sizeof *lclptr);
1036 if (lclptr == NULL) {
1037 settzname(); /* all we can do */
1038 _RWLOCK_UNLOCK(&lcl_rwlock);
1039 if (rdlocked)
1040 _RWLOCK_RDLOCK(&lcl_rwlock);
1041 return;
1042 }
1043 }
1044 #endif /* defined ALL_STATE */
1045 if (*name == '\0') {
1046 /*
1047 ** User wants it fast rather than right.
1048 */
1049 lclptr->leapcnt = 0; /* so, we're off a little */
1050 lclptr->timecnt = 0;
1051 lclptr->typecnt = 0;
1052 lclptr->ttis[0].tt_isdst = 0;
1053 lclptr->ttis[0].tt_gmtoff = 0;
1054 lclptr->ttis[0].tt_abbrind = 0;
1055 (void) strcpy(lclptr->chars, gmt);
1056 } else if (tzload(name, lclptr) != 0)
1057 if (name[0] == ':' || tzparse(name, lclptr, FALSE) != 0)
1058 (void) gmtload(lclptr);
1059 settzname();
1060 _RWLOCK_UNLOCK(&lcl_rwlock);
1061
1062 if (rdlocked)
1063 _RWLOCK_RDLOCK(&lcl_rwlock);
1064 }
1065
1066 void
1067 tzset(void)
1068 {
1069 tzset_basic(0);
1070 }
1071
1072 /*
1073 ** The easy way to behave "as if no library function calls" localtime
1074 ** is to not call it--so we drop its guts into "localsub", which can be
1075 ** freely called. (And no, the PANS doesn't require the above behavior--
1076 ** but it *is* desirable.)
1077 **
1078 ** The unused offset argument is for the benefit of mktime variants.
1079 */
1080
1081 /*ARGSUSED*/
1082 static void
1083 localsub(timep, offset, tmp)
1084 const time_t * const timep;
1085 const long offset;
1086 struct tm * const tmp;
1087 {
1088 struct state * sp;
1089 const struct ttinfo * ttisp;
1090 int i;
1091 const time_t t = *timep;
1092
1093 sp = lclptr;
1094 #ifdef ALL_STATE
1095 if (sp == NULL) {
1096 gmtsub(timep, offset, tmp);
1097 return;
1098 }
1099 #endif /* defined ALL_STATE */
1100 if (sp->timecnt == 0 || t < sp->ats[0]) {
1101 i = 0;
1102 while (sp->ttis[i].tt_isdst)
1103 if (++i >= sp->typecnt) {
1104 i = 0;
1105 break;
1106 }
1107 } else {
1108 for (i = 1; i < sp->timecnt; ++i)
1109 if (t < sp->ats[i])
1110 break;
1111 i = sp->types[i - 1];
1112 }
1113 ttisp = &sp->ttis[i];
1114 /*
1115 ** To get (wrong) behavior that's compatible with System V Release 2.0
1116 ** you'd replace the statement below with
1117 ** t += ttisp->tt_gmtoff;
1118 ** timesub(&t, 0L, sp, tmp);
1119 */
1120 timesub(&t, ttisp->tt_gmtoff, sp, tmp);
1121 tmp->tm_isdst = ttisp->tt_isdst;
1122 tzname[tmp->tm_isdst] = &sp->chars[ttisp->tt_abbrind];
1123 #ifdef TM_ZONE
1124 tmp->TM_ZONE = &sp->chars[ttisp->tt_abbrind];
1125 #endif /* defined TM_ZONE */
1126 }
1127
1128 struct tm *
1129 localtime(timep)
1130 const time_t * const timep;
1131 {
1132 static pthread_mutex_t localtime_mutex = PTHREAD_MUTEX_INITIALIZER;
1133 static pthread_key_t localtime_key = -1;
1134 struct tm *p_tm;
1135
1136 if (__isthreaded != 0) {
1137 if (localtime_key < 0) {
1138 _pthread_mutex_lock(&localtime_mutex);
1139 if (localtime_key < 0) {
1140 if (_pthread_key_create(&localtime_key, free) < 0) {
1141 _pthread_mutex_unlock(&localtime_mutex);
1142 return(NULL);
1143 }
1144 }
1145 _pthread_mutex_unlock(&localtime_mutex);
1146 }
1147 p_tm = _pthread_getspecific(localtime_key);
1148 if (p_tm == NULL) {
1149 if ((p_tm = (struct tm *)malloc(sizeof(struct tm)))
1150 == NULL)
1151 return(NULL);
1152 _pthread_setspecific(localtime_key, p_tm);
1153 }
1154 _RWLOCK_RDLOCK(&lcl_rwlock);
1155 tzset_basic(1);
1156 localsub(timep, 0L, p_tm);
1157 _RWLOCK_UNLOCK(&lcl_rwlock);
1158 return(p_tm);
1159 } else {
1160 tzset_basic(0);
1161 localsub(timep, 0L, &tm);
1162 return(&tm);
1163 }
1164 }
1165
1166 /*
1167 ** Re-entrant version of localtime.
1168 */
1169
1170 struct tm *
1171 localtime_r(timep, tm)
1172 const time_t * const timep;
1173 struct tm * tm;
1174 {
1175 _RWLOCK_RDLOCK(&lcl_rwlock);
1176 tzset_basic(1);
1177 localsub(timep, 0L, tm);
1178 _RWLOCK_UNLOCK(&lcl_rwlock);
1179 return tm;
1180 }
1181
1182 /*
1183 ** gmtsub is to gmtime as localsub is to localtime.
1184 */
1185
1186 static void
1187 gmtsub(timep, offset, tmp)
1188 const time_t * const timep;
1189 const long offset;
1190 struct tm * const tmp;
1191 {
1192 if (!gmt_is_set) {
1193 _MUTEX_LOCK(&gmt_mutex);
1194 if (!gmt_is_set) {
1195 #ifdef ALL_STATE
1196 gmtptr = (struct state *) malloc(sizeof *gmtptr);
1197 if (gmtptr != NULL)
1198 #endif /* defined ALL_STATE */
1199 gmtload(gmtptr);
1200 gmt_is_set = TRUE;
1201 }
1202 _MUTEX_UNLOCK(&gmt_mutex);
1203 }
1204 timesub(timep, offset, gmtptr, tmp);
1205 #ifdef TM_ZONE
1206 /*
1207 ** Could get fancy here and deliver something such as
1208 ** "UTC+xxxx" or "UTC-xxxx" if offset is non-zero,
1209 ** but this is no time for a treasure hunt.
1210 */
1211 if (offset != 0)
1212 tmp->TM_ZONE = wildabbr;
1213 else {
1214 #ifdef ALL_STATE
1215 if (gmtptr == NULL)
1216 tmp->TM_ZONE = gmt;
1217 else tmp->TM_ZONE = gmtptr->chars;
1218 #endif /* defined ALL_STATE */
1219 #ifndef ALL_STATE
1220 tmp->TM_ZONE = gmtptr->chars;
1221 #endif /* State Farm */
1222 }
1223 #endif /* defined TM_ZONE */
1224 }
1225
1226 struct tm *
1227 gmtime(timep)
1228 const time_t * const timep;
1229 {
1230 static pthread_mutex_t gmtime_mutex = PTHREAD_MUTEX_INITIALIZER;
1231 static pthread_key_t gmtime_key = -1;
1232 struct tm *p_tm;
1233
1234 if (__isthreaded != 0) {
1235 if (gmtime_key < 0) {
1236 _pthread_mutex_lock(&gmtime_mutex);
1237 if (gmtime_key < 0) {
1238 if (_pthread_key_create(&gmtime_key, free) < 0) {
1239 _pthread_mutex_unlock(&gmtime_mutex);
1240 return(NULL);
1241 }
1242 }
1243 _pthread_mutex_unlock(&gmtime_mutex);
1244 }
1245 /*
1246 * Changed to follow POSIX.1 threads standard, which
1247 * is what BSD currently has.
1248 */
1249 if ((p_tm = _pthread_getspecific(gmtime_key)) == NULL) {
1250 if ((p_tm = (struct tm *)malloc(sizeof(struct tm)))
1251 == NULL) {
1252 return(NULL);
1253 }
1254 _pthread_setspecific(gmtime_key, p_tm);
1255 }
1256 gmtsub(timep, 0L, p_tm);
1257 return(p_tm);
1258 }
1259 else {
1260 gmtsub(timep, 0L, &tm);
1261 return(&tm);
1262 }
1263 }
1264
1265 /*
1266 * Re-entrant version of gmtime.
1267 */
1268
1269 struct tm *
1270 gmtime_r(timep, tm)
1271 const time_t * const timep;
1272 struct tm * tm;
1273 {
1274 gmtsub(timep, 0L, tm);
1275 return tm;
1276 }
1277
1278 #ifdef STD_INSPIRED
1279
1280 struct tm *
1281 offtime(timep, offset)
1282 const time_t * const timep;
1283 const long offset;
1284 {
1285 gmtsub(timep, offset, &tm);
1286 return &tm;
1287 }
1288
1289 #endif /* defined STD_INSPIRED */
1290
1291 static void
1292 timesub(timep, offset, sp, tmp)
1293 const time_t * const timep;
1294 const long offset;
1295 const struct state * const sp;
1296 struct tm * const tmp;
1297 {
1298 const struct lsinfo * lp;
1299 long days;
1300 long rem;
1301 long y;
1302 int yleap;
1303 const int * ip;
1304 long corr;
1305 int hit;
1306 int i;
1307
1308 corr = 0;
1309 hit = 0;
1310 #ifdef ALL_STATE
1311 i = (sp == NULL) ? 0 : sp->leapcnt;
1312 #endif /* defined ALL_STATE */
1313 #ifndef ALL_STATE
1314 i = sp->leapcnt;
1315 #endif /* State Farm */
1316 while (--i >= 0) {
1317 lp = &sp->lsis[i];
1318 if (*timep >= lp->ls_trans) {
1319 if (*timep == lp->ls_trans) {
1320 hit = ((i == 0 && lp->ls_corr > 0) ||
1321 lp->ls_corr > sp->lsis[i - 1].ls_corr);
1322 if (hit)
1323 while (i > 0 &&
1324 sp->lsis[i].ls_trans ==
1325 sp->lsis[i - 1].ls_trans + 1 &&
1326 sp->lsis[i].ls_corr ==
1327 sp->lsis[i - 1].ls_corr + 1) {
1328 ++hit;
1329 --i;
1330 }
1331 }
1332 corr = lp->ls_corr;
1333 break;
1334 }
1335 }
1336 days = *timep / SECSPERDAY;
1337 rem = *timep % SECSPERDAY;
1338 #ifdef mc68k
1339 if (*timep == 0x80000000) {
1340 /*
1341 ** A 3B1 muffs the division on the most negative number.
1342 */
1343 days = -24855;
1344 rem = -11648;
1345 }
1346 #endif /* defined mc68k */
1347 rem += (offset - corr);
1348 while (rem < 0) {
1349 rem += SECSPERDAY;
1350 --days;
1351 }
1352 while (rem >= SECSPERDAY) {
1353 rem -= SECSPERDAY;
1354 ++days;
1355 }
1356 tmp->tm_hour = (int) (rem / SECSPERHOUR);
1357 rem = rem % SECSPERHOUR;
1358 tmp->tm_min = (int) (rem / SECSPERMIN);
1359 /*
1360 ** A positive leap second requires a special
1361 ** representation. This uses "... ??:59:60" et seq.
1362 */
1363 tmp->tm_sec = (int) (rem % SECSPERMIN) + hit;
1364 tmp->tm_wday = (int) ((EPOCH_WDAY + days) % DAYSPERWEEK);
1365 if (tmp->tm_wday < 0)
1366 tmp->tm_wday += DAYSPERWEEK;
1367 y = EPOCH_YEAR;
1368 #define LEAPS_THRU_END_OF(y) ((y) / 4 - (y) / 100 + (y) / 400)
1369 while (days < 0 || days >= (long) year_lengths[yleap = isleap(y)]) {
1370 long newy;
1371
1372 newy = y + days / DAYSPERNYEAR;
1373 if (days < 0)
1374 --newy;
1375 days -= (newy - y) * DAYSPERNYEAR +
1376 LEAPS_THRU_END_OF(newy - 1) -
1377 LEAPS_THRU_END_OF(y - 1);
1378 y = newy;
1379 }
1380 tmp->tm_year = y - TM_YEAR_BASE;
1381 tmp->tm_yday = (int) days;
1382 ip = mon_lengths[yleap];
1383 for (tmp->tm_mon = 0; days >= (long) ip[tmp->tm_mon]; ++(tmp->tm_mon))
1384 days = days - (long) ip[tmp->tm_mon];
1385 tmp->tm_mday = (int) (days + 1);
1386 tmp->tm_isdst = 0;
1387 #ifdef TM_GMTOFF
1388 tmp->TM_GMTOFF = offset;
1389 #endif /* defined TM_GMTOFF */
1390 }
1391
1392 char *
1393 ctime(timep)
1394 const time_t * const timep;
1395 {
1396 /*
1397 ** Section 4.12.3.2 of X3.159-1989 requires that
1398 ** The ctime function converts the calendar time pointed to by timer
1399 ** to local time in the form of a string. It is equivalent to
1400 ** asctime(localtime(timer))
1401 */
1402 return asctime(localtime(timep));
1403 }
1404
1405 char *
1406 ctime_r(timep, buf)
1407 const time_t * const timep;
1408 char * buf;
1409 {
1410 struct tm tm;
1411
1412 return asctime_r(localtime_r(timep, &tm), buf);
1413 }
1414
1415 /*
1416 ** Adapted from code provided by Robert Elz, who writes:
1417 ** The "best" way to do mktime I think is based on an idea of Bob
1418 ** Kridle's (so its said...) from a long time ago.
1419 ** [kridle@xinet.com as of 1996-01-16.]
1420 ** It does a binary search of the time_t space. Since time_t's are
1421 ** just 32 bits, its a max of 32 iterations (even at 64 bits it
1422 ** would still be very reasonable).
1423 */
1424
1425 #ifndef WRONG
1426 #define WRONG (-1)
1427 #endif /* !defined WRONG */
1428
1429 /*
1430 ** Simplified normalize logic courtesy Paul Eggert (eggert@twinsun.com).
1431 */
1432
1433 static int
1434 increment_overflow(number, delta)
1435 int * number;
1436 int delta;
1437 {
1438 int number0;
1439
1440 number0 = *number;
1441 *number += delta;
1442 return (*number < number0) != (delta < 0);
1443 }
1444
1445 static int
1446 normalize_overflow(tensptr, unitsptr, base)
1447 int * const tensptr;
1448 int * const unitsptr;
1449 const int base;
1450 {
1451 int tensdelta;
1452
1453 tensdelta = (*unitsptr >= 0) ?
1454 (*unitsptr / base) :
1455 (-1 - (-1 - *unitsptr) / base);
1456 *unitsptr -= tensdelta * base;
1457 return increment_overflow(tensptr, tensdelta);
1458 }
1459
1460 static int
1461 tmcomp(atmp, btmp)
1462 const struct tm * const atmp;
1463 const struct tm * const btmp;
1464 {
1465 int result;
1466
1467 if ((result = (atmp->tm_year - btmp->tm_year)) == 0 &&
1468 (result = (atmp->tm_mon - btmp->tm_mon)) == 0 &&
1469 (result = (atmp->tm_mday - btmp->tm_mday)) == 0 &&
1470 (result = (atmp->tm_hour - btmp->tm_hour)) == 0 &&
1471 (result = (atmp->tm_min - btmp->tm_min)) == 0)
1472 result = atmp->tm_sec - btmp->tm_sec;
1473 return result;
1474 }
1475
1476 static time_t
1477 time2sub(tmp, funcp, offset, okayp, do_norm_secs)
1478 struct tm * const tmp;
1479 void (* const funcp)(const time_t*, long, struct tm*);
1480 const long offset;
1481 int * const okayp;
1482 const int do_norm_secs;
1483 {
1484 const struct state * sp;
1485 int dir;
1486 int bits;
1487 int i, j ;
1488 int saved_seconds;
1489 time_t newt;
1490 time_t t;
1491 struct tm yourtm, mytm;
1492
1493 *okayp = FALSE;
1494 yourtm = *tmp;
1495 if (do_norm_secs) {
1496 if (normalize_overflow(&yourtm.tm_min, &yourtm.tm_sec,
1497 SECSPERMIN))
1498 return WRONG;
1499 }
1500 if (normalize_overflow(&yourtm.tm_hour, &yourtm.tm_min, MINSPERHOUR))
1501 return WRONG;
1502 if (normalize_overflow(&yourtm.tm_mday, &yourtm.tm_hour, HOURSPERDAY))
1503 return WRONG;
1504 if (normalize_overflow(&yourtm.tm_year, &yourtm.tm_mon, MONSPERYEAR))
1505 return WRONG;
1506 /*
1507 ** Turn yourtm.tm_year into an actual year number for now.
1508 ** It is converted back to an offset from TM_YEAR_BASE later.
1509 */
1510 if (increment_overflow(&yourtm.tm_year, TM_YEAR_BASE))
1511 return WRONG;
1512 while (yourtm.tm_mday <= 0) {
1513 if (increment_overflow(&yourtm.tm_year, -1))
1514 return WRONG;
1515 i = yourtm.tm_year + (1 < yourtm.tm_mon);
1516 yourtm.tm_mday += year_lengths[isleap(i)];
1517 }
1518 while (yourtm.tm_mday > DAYSPERLYEAR) {
1519 i = yourtm.tm_year + (1 < yourtm.tm_mon);
1520 yourtm.tm_mday -= year_lengths[isleap(i)];
1521 if (increment_overflow(&yourtm.tm_year, 1))
1522 return WRONG;
1523 }
1524 for ( ; ; ) {
1525 i = mon_lengths[isleap(yourtm.tm_year)][yourtm.tm_mon];
1526 if (yourtm.tm_mday <= i)
1527 break;
1528 yourtm.tm_mday -= i;
1529 if (++yourtm.tm_mon >= MONSPERYEAR) {
1530 yourtm.tm_mon = 0;
1531 if (increment_overflow(&yourtm.tm_year, 1))
1532 return WRONG;
1533 }
1534 }
1535 if (increment_overflow(&yourtm.tm_year, -TM_YEAR_BASE))
1536 return WRONG;
1537 /* Don't go below 1900 for POLA */
1538 if (yourtm.tm_year < 0)
1539 return WRONG;
1540 if (yourtm.tm_sec >= 0 && yourtm.tm_sec < SECSPERMIN)
1541 saved_seconds = 0;
1542 else if (yourtm.tm_year + TM_YEAR_BASE < EPOCH_YEAR) {
1543 /*
1544 ** We can't set tm_sec to 0, because that might push the
1545 ** time below the minimum representable time.
1546 ** Set tm_sec to 59 instead.
1547 ** This assumes that the minimum representable time is
1548 ** not in the same minute that a leap second was deleted from,
1549 ** which is a safer assumption than using 58 would be.
1550 */
1551 if (increment_overflow(&yourtm.tm_sec, 1 - SECSPERMIN))
1552 return WRONG;
1553 saved_seconds = yourtm.tm_sec;
1554 yourtm.tm_sec = SECSPERMIN - 1;
1555 } else {
1556 saved_seconds = yourtm.tm_sec;
1557 yourtm.tm_sec = 0;
1558 }
1559 /*
1560 ** Divide the search space in half
1561 ** (this works whether time_t is signed or unsigned).
1562 */
1563 bits = TYPE_BIT(time_t) - 1;
1564 /*
1565 ** If we have more than this, we will overflow tm_year for tmcomp().
1566 ** We should really return an error if we cannot represent it.
1567 */
1568 if (bits > 48)
1569 bits = 48;
1570 /*
1571 ** If time_t is signed, then 0 is just above the median,
1572 ** assuming two's complement arithmetic.
1573 ** If time_t is unsigned, then (1 << bits) is just above the median.
1574 */
1575 t = TYPE_SIGNED(time_t) ? 0 : (((time_t) 1) << bits);
1576 for ( ; ; ) {
1577 (*funcp)(&t, offset, &mytm);
1578 dir = tmcomp(&mytm, &yourtm);
1579 if (dir != 0) {
1580 if (bits-- < 0)
1581 return WRONG;
1582 if (bits < 0)
1583 --t; /* may be needed if new t is minimal */
1584 else if (dir > 0)
1585 t -= ((time_t) 1) << bits;
1586 else t += ((time_t) 1) << bits;
1587 continue;
1588 }
1589 if (yourtm.tm_isdst < 0 || mytm.tm_isdst == yourtm.tm_isdst)
1590 break;
1591 /*
1592 ** Right time, wrong type.
1593 ** Hunt for right time, right type.
1594 ** It's okay to guess wrong since the guess
1595 ** gets checked.
1596 */
1597 sp = (funcp == localsub) ? lclptr : gmtptr;
1598 #ifdef ALL_STATE
1599 if (sp == NULL)
1600 return WRONG;
1601 #endif /* defined ALL_STATE */
1602 for (i = sp->typecnt - 1; i >= 0; --i) {
1603 if (sp->ttis[i].tt_isdst != yourtm.tm_isdst)
1604 continue;
1605 for (j = sp->typecnt - 1; j >= 0; --j) {
1606 if (sp->ttis[j].tt_isdst == yourtm.tm_isdst)
1607 continue;
1608 newt = t + sp->ttis[j].tt_gmtoff -
1609 sp->ttis[i].tt_gmtoff;
1610 (*funcp)(&newt, offset, &mytm);
1611 if (tmcomp(&mytm, &yourtm) != 0)
1612 continue;
1613 if (mytm.tm_isdst != yourtm.tm_isdst)
1614 continue;
1615 /*
1616 ** We have a match.
1617 */
1618 t = newt;
1619 goto label;
1620 }
1621 }
1622 return WRONG;
1623 }
1624 label:
1625 newt = t + saved_seconds;
1626 if ((newt < t) != (saved_seconds < 0))
1627 return WRONG;
1628 t = newt;
1629 (*funcp)(&t, offset, tmp);
1630 *okayp = TRUE;
1631 return t;
1632 }
1633
1634 static time_t
1635 time2(tmp, funcp, offset, okayp)
1636 struct tm * const tmp;
1637 void (* const funcp)(const time_t*, long, struct tm*);
1638 const long offset;
1639 int * const okayp;
1640 {
1641 time_t t;
1642
1643 /*
1644 ** First try without normalization of seconds
1645 ** (in case tm_sec contains a value associated with a leap second).
1646 ** If that fails, try with normalization of seconds.
1647 */
1648 t = time2sub(tmp, funcp, offset, okayp, FALSE);
1649 return *okayp ? t : time2sub(tmp, funcp, offset, okayp, TRUE);
1650 }
1651
1652 static time_t
1653 time1(tmp, funcp, offset)
1654 struct tm * const tmp;
1655 void (* const funcp)(const time_t *, long, struct tm *);
1656 const long offset;
1657 {
1658 time_t t;
1659 const struct state * sp;
1660 int samei, otheri;
1661 int sameind, otherind;
1662 int i;
1663 int nseen;
1664 int seen[TZ_MAX_TYPES];
1665 int types[TZ_MAX_TYPES];
1666 int okay;
1667
1668 if (tmp->tm_isdst > 1)
1669 tmp->tm_isdst = 1;
1670 t = time2(tmp, funcp, offset, &okay);
1671 #ifdef PCTS
1672 /*
1673 ** PCTS code courtesy Grant Sullivan (grant@osf.org).
1674 */
1675 if (okay)
1676 return t;
1677 if (tmp->tm_isdst < 0)
1678 tmp->tm_isdst = 0; /* reset to std and try again */
1679 #endif /* defined PCTS */
1680 #ifndef PCTS
1681 if (okay || tmp->tm_isdst < 0)
1682 return t;
1683 #endif /* !defined PCTS */
1684 /*
1685 ** We're supposed to assume that somebody took a time of one type
1686 ** and did some math on it that yielded a "struct tm" that's bad.
1687 ** We try to divine the type they started from and adjust to the
1688 ** type they need.
1689 */
1690 sp = (funcp == localsub) ? lclptr : gmtptr;
1691 #ifdef ALL_STATE
1692 if (sp == NULL)
1693 return WRONG;
1694 #endif /* defined ALL_STATE */
1695 for (i = 0; i < sp->typecnt; ++i)
1696 seen[i] = FALSE;
1697 nseen = 0;
1698 for (i = sp->timecnt - 1; i >= 0; --i)
1699 if (!seen[sp->types[i]]) {
1700 seen[sp->types[i]] = TRUE;
1701 types[nseen++] = sp->types[i];
1702 }
1703 for (sameind = 0; sameind < nseen; ++sameind) {
1704 samei = types[sameind];
1705 if (sp->ttis[samei].tt_isdst != tmp->tm_isdst)
1706 continue;
1707 for (otherind = 0; otherind < nseen; ++otherind) {
1708 otheri = types[otherind];
1709 if (sp->ttis[otheri].tt_isdst == tmp->tm_isdst)
1710 continue;
1711 tmp->tm_sec += sp->ttis[otheri].tt_gmtoff -
1712 sp->ttis[samei].tt_gmtoff;
1713 tmp->tm_isdst = !tmp->tm_isdst;
1714 t = time2(tmp, funcp, offset, &okay);
1715 if (okay)
1716 return t;
1717 tmp->tm_sec -= sp->ttis[otheri].tt_gmtoff -
1718 sp->ttis[samei].tt_gmtoff;
1719 tmp->tm_isdst = !tmp->tm_isdst;
1720 }
1721 }
1722 return WRONG;
1723 }
1724
1725 time_t
1726 mktime(tmp)
1727 struct tm * const tmp;
1728 {
1729 time_t mktime_return_value;
1730 _RWLOCK_RDLOCK(&lcl_rwlock);
1731 tzset_basic(1);
1732 mktime_return_value = time1(tmp, localsub, 0L);
1733 _RWLOCK_UNLOCK(&lcl_rwlock);
1734 return(mktime_return_value);
1735 }
1736
1737 #ifdef STD_INSPIRED
1738
1739 time_t
1740 timelocal(tmp)
1741 struct tm * const tmp;
1742 {
1743 tmp->tm_isdst = -1; /* in case it wasn't initialized */
1744 return mktime(tmp);
1745 }
1746
1747 time_t
1748 timegm(tmp)
1749 struct tm * const tmp;
1750 {
1751 tmp->tm_isdst = 0;
1752 return time1(tmp, gmtsub, 0L);
1753 }
1754
1755 time_t
1756 timeoff(tmp, offset)
1757 struct tm * const tmp;
1758 const long offset;
1759 {
1760 tmp->tm_isdst = 0;
1761 return time1(tmp, gmtsub, offset);
1762 }
1763
1764 #endif /* defined STD_INSPIRED */
1765
1766 #ifdef CMUCS
1767
1768 /*
1769 ** The following is supplied for compatibility with
1770 ** previous versions of the CMUCS runtime library.
1771 */
1772
1773 long
1774 gtime(tmp)
1775 struct tm * const tmp;
1776 {
1777 const time_t t = mktime(tmp);
1778
1779 if (t == WRONG)
1780 return -1;
1781 return t;
1782 }
1783
1784 #endif /* defined CMUCS */
1785
1786 /*
1787 ** XXX--is the below the right way to conditionalize??
1788 */
1789
1790 #ifdef STD_INSPIRED
1791
1792 /*
1793 ** IEEE Std 1003.1-1988 (POSIX) legislates that 536457599
1794 ** shall correspond to "Wed Dec 31 23:59:59 UTC 1986", which
1795 ** is not the case if we are accounting for leap seconds.
1796 ** So, we provide the following conversion routines for use
1797 ** when exchanging timestamps with POSIX conforming systems.
1798 */
1799
1800 static long
1801 leapcorr(timep)
1802 time_t * timep;
1803 {
1804 struct state * sp;
1805 struct lsinfo * lp;
1806 int i;
1807
1808 sp = lclptr;
1809 i = sp->leapcnt;
1810 while (--i >= 0) {
1811 lp = &sp->lsis[i];
1812 if (*timep >= lp->ls_trans)
1813 return lp->ls_corr;
1814 }
1815 return 0;
1816 }
1817
1818 time_t
1819 time2posix(t)
1820 time_t t;
1821 {
1822 tzset();
1823 return t - leapcorr(&t);
1824 }
1825
1826 time_t
1827 posix2time(t)
1828 time_t t;
1829 {
1830 time_t x;
1831 time_t y;
1832
1833 tzset();
1834 /*
1835 ** For a positive leap second hit, the result
1836 ** is not unique. For a negative leap second
1837 ** hit, the corresponding time doesn't exist,
1838 ** so we return an adjacent second.
1839 */
1840 x = t + leapcorr(&t);
1841 y = x - leapcorr(&x);
1842 if (y < t) {
1843 do {
1844 x++;
1845 y = x - leapcorr(&x);
1846 } while (y < t);
1847 if (t != y)
1848 return x - 1;
1849 } else if (y > t) {
1850 do {
1851 --x;
1852 y = x - leapcorr(&x);
1853 } while (y > t);
1854 if (t != y)
1855 return x + 1;
1856 }
1857 return x;
1858 }
1859
1860 #endif /* defined STD_INSPIRED */
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