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kernel - Remove debugging kprintf
[dragonfly.git] / lib / libc / stdtime / localtime.c
blob34ade3aba5744a75f8c00ff64b5ba02d1a7a3746
1 /*
2 ** This file is in the public domain, so clarified as of
3 ** 1996-06-05 by Arthur David Olson.
4 **
5 ** $FreeBSD: head/contrib/tzcode/stdtime/localtime.c 226828 2011-10-27 08:44:07Z trociny $
6 */
7
8 /*
9 ** Leap second handling from Bradley White.
10 ** POSIX-style TZ environment variable handling from Guy Harris.
11 */
12
13 /*LINTLIBRARY*/
14
15 #include "namespace.h"
16 #include <sys/types.h>
17 #include <sys/stat.h>
18
19 #include <errno.h>
20 #include <fcntl.h>
21 #include <time.h>
22 #include <pthread.h>
23 #include "private.h"
24 #include "libc_private.h"
25 #include <un-namespace.h>
26
27 #include "tzfile.h"
28
29 #ifndef TZ_ABBR_MAX_LEN
30 #define TZ_ABBR_MAX_LEN 16
31 #endif /* !defined TZ_ABBR_MAX_LEN */
32
33 #ifndef TZ_ABBR_CHAR_SET
34 #define TZ_ABBR_CHAR_SET \
35 "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789 :+-._"
36 #endif /* !defined TZ_ABBR_CHAR_SET */
37
38 #ifndef TZ_ABBR_ERR_CHAR
39 #define TZ_ABBR_ERR_CHAR '_'
40 #endif /* !defined TZ_ABBR_ERR_CHAR */
41
42 #define _MUTEX_LOCK(x) if (__isthreaded) _pthread_mutex_lock(x)
43 #define _MUTEX_UNLOCK(x) if (__isthreaded) _pthread_mutex_unlock(x)
44
45 #define _RWLOCK_RDLOCK(x) \
46 do { \
47 if (__isthreaded) _pthread_rwlock_rdlock(x); \
48 } while (0)
49
50 #define _RWLOCK_WRLOCK(x) \
51 do { \
52 if (__isthreaded) _pthread_rwlock_wrlock(x); \
53 } while (0)
54
55 #define _RWLOCK_UNLOCK(x) \
56 do { \
57 if (__isthreaded) _pthread_rwlock_unlock(x); \
58 } while (0)
59
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
81 static char wildabbr[] = WILDABBR;
82
83 static const char gmt[] = "UTC";
84
85 /*
86 ** The DST rules to use if TZ has no rules and we can't load TZDEFRULES.
87 ** We default to US rules as of 1999-08-17.
88 ** POSIX 1003.1 section 8.1.1 says that the default DST rules are
89 ** implementation dependent; for historical reasons, US rules are a
90 ** common default.
91 */
92 #ifndef TZDEFRULESTRING
93 #define TZDEFRULESTRING ",M4.1.0,M10.5.0"
94 #endif /* !defined TZDEFDST */
95
96 struct ttinfo { /* time type information */
97 int_fast32_t tt_gmtoff; /* UT offset in seconds */
98 int tt_isdst; /* used to set tm_isdst */
99 int tt_abbrind; /* abbreviation list index */
100 int tt_ttisstd; /* TRUE if transition is std time */
101 int tt_ttisgmt; /* TRUE if transition is UT */
102 };
103
104 struct lsinfo { /* leap second information */
105 time_t ls_trans; /* transition time */
106 int_fast64_t ls_corr; /* correction to apply */
107 };
108
109 #define BIGGEST(a, b) (((a) > (b)) ? (a) : (b))
110
111 #ifdef TZNAME_MAX
112 #define MY_TZNAME_MAX TZNAME_MAX
113 #endif /* defined TZNAME_MAX */
114 #ifndef TZNAME_MAX
115 #define MY_TZNAME_MAX 255
116 #endif /* !defined TZNAME_MAX */
117
118 struct state {
119 int leapcnt;
120 int timecnt;
121 int typecnt;
122 int charcnt;
123 int goback;
124 int goahead;
125 time_t ats[TZ_MAX_TIMES];
126 unsigned char types[TZ_MAX_TIMES];
127 struct ttinfo ttis[TZ_MAX_TYPES];
128 char chars[BIGGEST(BIGGEST(TZ_MAX_CHARS + 1, sizeof gmt),
129 (2 * (MY_TZNAME_MAX + 1)))];
130 struct lsinfo lsis[TZ_MAX_LEAPS];
131 int defaulttype; /* for early times or if no transitions */
132 };
133
134 struct rule {
135 int r_type; /* type of rule--see below */
136 int r_day; /* day number of rule */
137 int r_week; /* week number of rule */
138 int r_mon; /* month number of rule */
139 int_fast32_t r_time; /* transition time of rule */
140 };
141
142 #define JULIAN_DAY 0 /* Jn - Julian day */
143 #define DAY_OF_YEAR 1 /* n - day of year */
144 #define MONTH_NTH_DAY_OF_WEEK 2 /* Mm.n.d - month, week, day of week */
145
146 /*
147 ** Prototypes for static functions.
148 */
149
150 static int_fast32_t detzcode(const char * codep);
151 static int_fast64_t detzcode64(const char * codep);
152 static int differ_by_repeat(time_t t1, time_t t0);
153 static const char * getzname(const char * strp) __pure;
154 static const char * getqzname(const char * strp, const int delim) __pure;
155 static const char * getnum(const char * strp, int * nump, int min,
156 int max);
157 static const char * getsecs(const char * strp, int_fast32_t * secsp);
158 static const char * getoffset(const char * strp, int_fast32_t * offsetp);
159 static const char * getrule(const char * strp, struct rule * rulep);
160 static void gmtload(struct state * sp);
161 static struct tm * gmtsub(const time_t * timep, int_fast32_t offset,
162 struct tm * tmp);
163 static struct tm * localsub(const time_t * timep, int_fast32_t offset,
164 struct tm * tmp);
165 static int increment_overflow(int * number, int delta);
166 static int leaps_thru_end_of(int y) __pure;
167 static int increment_overflow32(int_fast32_t * number, int delta);
168 static int increment_overflow_time(time_t *t, int_fast32_t delta);
169 static int normalize_overflow32(int_fast32_t * tensptr,
170 int * unitsptr, int base);
171 static int normalize_overflow(int * tensptr, int * unitsptr,
172 int base);
173 static void settzname(void);
174 static time_t time1(struct tm * tmp,
175 struct tm * (*funcp)(const time_t *,
176 int_fast32_t, struct tm *),
177 int_fast32_t offset);
178 static time_t time2(struct tm *tmp,
179 struct tm * (*funcp)(const time_t *,
180 int_fast32_t, struct tm*),
181 int_fast32_t offset, int * okayp);
182 static time_t time2sub(struct tm *tmp,
183 struct tm * (*funcp)(const time_t *,
184 int_fast32_t, struct tm*),
185 int_fast32_t offset, int * okayp, int do_norm_secs);
186 static struct tm * timesub(const time_t * timep, int_fast32_t offset,
187 const struct state * sp, struct tm * tmp);
188 static int tmcomp(const struct tm * atmp,
189 const struct tm * btmp);
190 static int_fast32_t transtime(int year, const struct rule * rulep,
191 int_fast32_t offset) __pure;
192 static int typesequiv(const struct state * sp, int a, int b);
193 static int tzload(const char * name, struct state * sp,
194 int doextend);
195 static int tzparse(const char * name, struct state * sp,
196 int lastditch);
197
198 static struct state lclmem;
199 static struct state gmtmem;
200 #define lclptr (&lclmem)
201 #define gmtptr (&gmtmem)
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 pthread_once_t gmt_once = PTHREAD_ONCE_INIT;
210 static pthread_rwlock_t lcl_rwlock = PTHREAD_RWLOCK_INITIALIZER;
211 static pthread_once_t gmtime_once = PTHREAD_ONCE_INIT;
212 static pthread_key_t gmtime_key;
213 static int gmtime_key_error;
214 static pthread_once_t localtime_once = PTHREAD_ONCE_INIT;
215 static pthread_key_t localtime_key;
216 static int localtime_key_error;
217
218 char * tzname[2] = {
219 wildabbr,
220 wildabbr
221 };
222
223 /*
224 ** Section 4.12.3 of X3.159-1989 requires that
225 ** Except for the strftime function, these functions [asctime,
226 ** ctime, gmtime, localtime] return values in one of two static
227 ** objects: a broken-down time structure and an array of char.
228 ** Thanks to Paul Eggert for noting this.
229 */
230
231 static struct tm tm;
232
233 long timezone = 0;
234 int daylight = 0;
235
236 static int_fast32_t
237 detzcode(const char * const codep)
238 {
239 int_fast32_t result;
240 int i;
241
242 result = (codep[0] & 0x80) ? -1 : 0;
243 for (i = 0; i < 4; ++i)
244 result = (result << 8) | (codep[i] & 0xff);
245 return result;
246 }
247
248 static int_fast64_t
249 detzcode64(const char * const codep)
250 {
251 int_fast64_t result;
252 int i;
253
254 result = (codep[0] & 0x80) ? -1 : 0;
255 for (i = 0; i < 8; ++i)
256 result = (result << 8) | (codep[i] & 0xff);
257 return result;
258 }
259
260 static void
261 settzname(void)
262 {
263 struct state * const sp = lclptr;
264 int i;
265
266 tzname[0] = wildabbr;
267 tzname[1] = wildabbr;
268 daylight = 0;
269 timezone = 0;
270
271 /*
272 ** And to get the latest zone names into tzname. . .
273 */
274 for (i = 0; i < sp->typecnt; ++i) {
275 const struct ttinfo * const ttisp = &sp->ttis[i];
276
277 tzname[ttisp->tt_isdst] = &sp->chars[ttisp->tt_abbrind];
278 }
279 for (i = 0; i < sp->timecnt; ++i) {
280 const struct ttinfo * const ttisp = &sp->ttis[sp->types[i]];
281
282 tzname[ttisp->tt_isdst] =
283 &sp->chars[ttisp->tt_abbrind];
284 if (ttisp->tt_isdst)
285 daylight = 1;
286 if (!ttisp->tt_isdst)
287 timezone = -(ttisp->tt_gmtoff);
288 }
289 /*
290 ** Finally, scrub the abbreviations.
291 ** First, replace bogus characters.
292 */
293 for (i = 0; i < sp->charcnt; ++i)
294 if (strchr(TZ_ABBR_CHAR_SET, sp->chars[i]) == NULL)
295 sp->chars[i] = TZ_ABBR_ERR_CHAR;
296 /*
297 ** Second, truncate long abbreviations.
298 */
299 for (i = 0; i < sp->typecnt; ++i) {
300 const struct ttinfo * const ttisp = &sp->ttis[i];
301 char * cp = &sp->chars[ttisp->tt_abbrind];
302
303 if (strlen(cp) > TZ_ABBR_MAX_LEN &&
304 strcmp(cp, GRANDPARENTED) != 0)
305 *(cp + TZ_ABBR_MAX_LEN) = '\0';
306 }
307 }
308
309 static int
310 differ_by_repeat(const time_t t1, const time_t t0)
311 {
312 if (TYPE_BIT(time_t) - TYPE_SIGNED(time_t) < SECSPERREPEAT_BITS)
313 return 0;
314 return t1 - t0 == SECSPERREPEAT;
315 }
316
317 static int
318 tzload(const char *name, struct state * const sp, const int doextend)
319 {
320 const char * p;
321 int i;
322 int fid;
323 int stored;
324 int nread;
325 int res;
326 typedef union {
327 struct tzhead tzhead;
328 char buf[2 * sizeof(struct tzhead) +
329 2 * sizeof *sp +
330 4 * TZ_MAX_TIMES];
331 } u_t;
332 u_t *u;
333
334 u = NULL;
335 res = -1;
336 sp->goback = sp->goahead = FALSE;
337
338 /* XXX The following is from OpenBSD, and I'm not sure it is correct */
339 if (name != NULL && issetugid() != 0)
340 if ((name[0] == ':' && name[1] == '/') ||
341 name[0] == '/' || strchr(name, '.'))
342 name = NULL;
343 if (name == NULL && (name = TZDEFAULT) == NULL)
344 goto out;
345 {
346 int doaccess;
347 struct stat stab;
348 /*
349 ** Section 4.9.1 of the C standard says that
350 ** "FILENAME_MAX expands to an integral constant expression
351 ** that is the size needed for an array of char large enough
352 ** to hold the longest file name string that the implementation
353 ** guarantees can be opened."
354 */
355 char *fullname;
356
357 fullname = malloc(FILENAME_MAX + 1);
358 if (fullname == NULL)
359 goto out;
360
361 if (name[0] == ':')
362 ++name;
363 doaccess = name[0] == '/';
364 if (!doaccess) {
365 if ((p = TZDIR) == NULL) {
366 free(fullname);
367 goto out;
368 }
369 if (strlen(p) + 1 + strlen(name) >= FILENAME_MAX) {
370 free(fullname);
371 goto out;
372 }
373 strcpy(fullname, p);
374 strcat(fullname, "/");
375 strcat(fullname, name);
376 /*
377 ** Set doaccess if '.' (as in "../") shows up in name.
378 */
379 if (strchr(name, '.') != NULL)
380 doaccess = TRUE;
381 name = fullname;
382 }
383 if (doaccess && access(name, R_OK) != 0) {
384 free(fullname);
385 goto out;
386 }
387 if ((fid = _open(name, O_RDONLY)) == -1) {
388 free(fullname);
389 goto out;
390 }
391 if ((_fstat(fid, &stab) < 0) || !S_ISREG(stab.st_mode)) {
392 free(fullname);
393 _close(fid);
394 goto out;
395 }
396 free(fullname);
397 }
398 u = malloc(sizeof(*u));
399 if (u == NULL)
400 goto out;
401 nread = _read(fid, u->buf, sizeof u->buf);
402 if (_close(fid) < 0 || nread <= 0)
403 goto out;
404 for (stored = 4; stored <= 8; stored *= 2) {
405 int ttisstdcnt;
406 int ttisgmtcnt;
407 int timecnt;
408
409 ttisstdcnt = (int) detzcode(u->tzhead.tzh_ttisstdcnt);
410 ttisgmtcnt = (int) detzcode(u->tzhead.tzh_ttisgmtcnt);
411 sp->leapcnt = (int) detzcode(u->tzhead.tzh_leapcnt);
412 sp->timecnt = (int) detzcode(u->tzhead.tzh_timecnt);
413 sp->typecnt = (int) detzcode(u->tzhead.tzh_typecnt);
414 sp->charcnt = (int) detzcode(u->tzhead.tzh_charcnt);
415 p = u->tzhead.tzh_charcnt + sizeof u->tzhead.tzh_charcnt;
416 if (sp->leapcnt < 0 || sp->leapcnt > TZ_MAX_LEAPS ||
417 sp->typecnt <= 0 || sp->typecnt > TZ_MAX_TYPES ||
418 sp->timecnt < 0 || sp->timecnt > TZ_MAX_TIMES ||
419 sp->charcnt < 0 || sp->charcnt > TZ_MAX_CHARS ||
420 (ttisstdcnt != sp->typecnt && ttisstdcnt != 0) ||
421 (ttisgmtcnt != sp->typecnt && ttisgmtcnt != 0))
422 goto out;
423 if (nread - (p - u->buf) <
424 sp->timecnt * stored + /* ats */
425 sp->timecnt + /* types */
426 sp->typecnt * 6 + /* ttinfos */
427 sp->charcnt + /* chars */
428 sp->leapcnt * (stored + 4) + /* lsinfos */
429 ttisstdcnt + /* ttisstds */
430 ttisgmtcnt) /* ttisgmts */
431 goto out;
432 timecnt = 0;
433 for (i = 0; i < sp->timecnt; ++i) {
434 int_fast64_t at
435 = stored == 4 ? detzcode(p) : detzcode64(p);
436 sp->types[i] = ((TYPE_SIGNED(time_t)
437 ? time_t_min <= at
438 : 0 <= at)
439 && at <= time_t_max);
440 if (sp->types[i]) {
441 if (i && !timecnt && at != time_t_min) {
442 /*
443 ** Keep the earlier record, but tweak
444 ** it so that it starts with the
445 ** minimum time_t value.
446 */
447 sp->types[i - 1] = 1;
448 sp->ats[timecnt++] = time_t_min;
449 }
450 sp->ats[timecnt++] = at;
451 }
452 p += stored;
453 }
454 timecnt = 0;
455 for (i = 0; i < sp->timecnt; ++i) {
456 unsigned char typ = *p++;
457 if (sp->typecnt <= typ)
458 goto out;
459 if (sp->types[i])
460 sp->types[timecnt++] = typ;
461 }
462 sp->timecnt = timecnt;
463 for (i = 0; i < sp->typecnt; ++i) {
464 struct ttinfo * ttisp;
465
466 ttisp = &sp->ttis[i];
467 ttisp->tt_gmtoff = detzcode(p);
468 p += 4;
469 ttisp->tt_isdst = (unsigned char) *p++;
470 if (ttisp->tt_isdst != 0 && ttisp->tt_isdst != 1)
471 goto out;
472 ttisp->tt_abbrind = (unsigned char) *p++;
473 if (ttisp->tt_abbrind < 0 ||
474 ttisp->tt_abbrind > sp->charcnt)
475 goto out;
476 }
477 for (i = 0; i < sp->charcnt; ++i)
478 sp->chars[i] = *p++;
479 sp->chars[i] = '\0'; /* ensure '\0' at end */
480 for (i = 0; i < sp->leapcnt; ++i) {
481 struct lsinfo * lsisp;
482
483 lsisp = &sp->lsis[i];
484 lsisp->ls_trans = (stored == 4) ?
485 detzcode(p) : detzcode64(p);
486 p += stored;
487 lsisp->ls_corr = detzcode(p);
488 p += 4;
489 }
490 for (i = 0; i < sp->typecnt; ++i) {
491 struct ttinfo * ttisp;
492
493 ttisp = &sp->ttis[i];
494 if (ttisstdcnt == 0)
495 ttisp->tt_ttisstd = FALSE;
496 else {
497 ttisp->tt_ttisstd = *p++;
498 if (ttisp->tt_ttisstd != TRUE &&
499 ttisp->tt_ttisstd != FALSE)
500 goto out;
501 }
502 }
503 for (i = 0; i < sp->typecnt; ++i) {
504 struct ttinfo * ttisp;
505
506 ttisp = &sp->ttis[i];
507 if (ttisgmtcnt == 0)
508 ttisp->tt_ttisgmt = FALSE;
509 else {
510 ttisp->tt_ttisgmt = *p++;
511 if (ttisp->tt_ttisgmt != TRUE &&
512 ttisp->tt_ttisgmt != FALSE)
513 goto out;
514 }
515 }
516 /*
517 ** If this is an old file, we're done.
518 */
519 if (u->tzhead.tzh_version[0] == '\0')
520 break;
521 nread -= p - u->buf;
522 for (i = 0; i < nread; ++i)
523 u->buf[i] = p[i];
524 /*
525 ** If this is a signed narrow time_t system, we're done.
526 */
527 if (TYPE_SIGNED(time_t) && stored >= (int) sizeof(time_t))
528 break;
529 }
530 if (doextend && nread > 2 &&
531 u->buf[0] == '\n' && u->buf[nread - 1] == '\n' &&
532 sp->typecnt + 2 <= TZ_MAX_TYPES) {
533 struct state *ts;
534 int result;
535
536 ts = malloc(sizeof(*ts));
537 if (ts == NULL)
538 goto out;
539 u->buf[nread - 1] = '\0';
540 result = tzparse(&u->buf[1], ts, FALSE);
541 if (result == 0 && ts->typecnt == 2 &&
542 sp->charcnt + ts->charcnt <= TZ_MAX_CHARS) {
543 for (i = 0; i < 2; ++i)
544 ts->ttis[i].tt_abbrind +=
545 sp->charcnt;
546 for (i = 0; i < ts->charcnt; ++i)
547 sp->chars[sp->charcnt++] =
548 ts->chars[i];
549 i = 0;
550 while (i < ts->timecnt &&
551 ts->ats[i] <=
552 sp->ats[sp->timecnt - 1])
553 ++i;
554 while (i < ts->timecnt &&
555 sp->timecnt < TZ_MAX_TIMES) {
556 sp->ats[sp->timecnt] =
557 ts->ats[i];
558 sp->types[sp->timecnt] =
559 sp->typecnt +
560 ts->types[i];
561 ++sp->timecnt;
562 ++i;
563 }
564 sp->ttis[sp->typecnt++] = ts->ttis[0];
565 sp->ttis[sp->typecnt++] = ts->ttis[1];
566 }
567 free(ts);
568 }
569 if (sp->timecnt > 1) {
570 for (i = 1; i < sp->timecnt; ++i)
571 if (typesequiv(sp, sp->types[i], sp->types[0]) &&
572 differ_by_repeat(sp->ats[i], sp->ats[0])) {
573 sp->goback = TRUE;
574 break;
575 }
576 for (i = sp->timecnt - 2; i >= 0; --i)
577 if (typesequiv(sp, sp->types[sp->timecnt - 1],
578 sp->types[i]) &&
579 differ_by_repeat(sp->ats[sp->timecnt - 1],
580 sp->ats[i])) {
581 sp->goahead = TRUE;
582 break;
583 }
584 }
585 /*
586 ** If type 0 is is unused in transitions,
587 ** it's the type to use for early times.
588 */
589 for (i = 0; i < sp->typecnt; ++i)
590 if (sp->types[i] == 0)
591 break;
592 i = (i >= sp->typecnt) ? 0 : -1;
593 /*
594 ** Absent the above,
595 ** if there are transition times
596 ** and the first transition is to a daylight time
597 ** find the standard type less than and closest to
598 ** the type of the first transition.
599 */
600 if (i < 0 && sp->timecnt > 0 && sp->ttis[sp->types[0]].tt_isdst) {
601 i = sp->types[0];
602 while (--i >= 0)
603 if (!sp->ttis[i].tt_isdst)
604 break;
605 }
606 /*
607 ** If no result yet, find the first standard type.
608 ** If there is none, punt to type zero.
609 */
610 if (i < 0) {
611 i = 0;
612 while (sp->ttis[i].tt_isdst)
613 if (++i >= sp->typecnt) {
614 i = 0;
615 break;
616 }
617 }
618 sp->defaulttype = i;
619 res = 0;
620 out:
621 if (u != NULL)
622 free(u);
623 return (res);
624 }
625
626 static int
627 typesequiv(const struct state * const sp, const int a, const int b)
628 {
629 int result;
630
631 if (sp == NULL ||
632 a < 0 || a >= sp->typecnt ||
633 b < 0 || b >= sp->typecnt)
634 result = FALSE;
635 else {
636 const struct ttinfo * ap = &sp->ttis[a];
637 const struct ttinfo * bp = &sp->ttis[b];
638 result = ap->tt_gmtoff == bp->tt_gmtoff &&
639 ap->tt_isdst == bp->tt_isdst &&
640 ap->tt_ttisstd == bp->tt_ttisstd &&
641 ap->tt_ttisgmt == bp->tt_ttisgmt &&
642 strcmp(&sp->chars[ap->tt_abbrind],
643 &sp->chars[bp->tt_abbrind]) == 0;
644 }
645 return result;
646 }
647
648 static const int mon_lengths[2][MONSPERYEAR] = {
649 { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 },
650 { 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }
651 };
652
653 static const int year_lengths[2] = {
654 DAYSPERNYEAR, DAYSPERLYEAR
655 };
656
657 /*
658 ** Given a pointer into a time zone string, scan until a character that is not
659 ** a valid character in a zone name is found. Return a pointer to that
660 ** character.
661 */
662
663 static const char *
664 getzname(const char *strp)
665 {
666 char c;
667
668 while ((c = *strp) != '\0' && !is_digit(c) && c != ',' && c != '-' &&
669 c != '+')
670 ++strp;
671 return strp;
672 }
673
674 /*
675 ** Given a pointer into an extended time zone string, scan until the ending
676 ** delimiter of the zone name is located. Return a pointer to the delimiter.
677 **
678 ** As with getzname above, the legal character set is actually quite
679 ** restricted, with other characters producing undefined results.
680 ** We don't do any checking here; checking is done later in common-case code.
681 */
682
683 static const char *
684 getqzname(const char *strp, const int delim)
685 {
686 int c;
687
688 while ((c = *strp) != '\0' && c != delim)
689 ++strp;
690 return strp;
691 }
692
693 /*
694 ** Given a pointer into a time zone string, extract a number from that string.
695 ** Check that the number is within a specified range; if it is not, return
696 ** NULL.
697 ** Otherwise, return a pointer to the first character not part of the number.
698 */
699
700 static const char *
701 getnum(const char *strp, int * const nump, const int min, const int max)
702 {
703 char c;
704 int num;
705
706 if (strp == NULL || !is_digit(c = *strp))
707 return NULL;
708 num = 0;
709 do {
710 num = num * 10 + (c - '0');
711 if (num > max)
712 return NULL; /* illegal value */
713 c = *++strp;
714 } while (is_digit(c));
715 if (num < min)
716 return NULL; /* illegal value */
717 *nump = num;
718 return strp;
719 }
720
721 /*
722 ** Given a pointer into a time zone string, extract a number of seconds,
723 ** in hh[:mm[:ss]] form, from the string.
724 ** If any error occurs, return NULL.
725 ** Otherwise, return a pointer to the first character not part of the number
726 ** of seconds.
727 */
728
729 static const char *
730 getsecs(const char *strp, int_fast32_t * const secsp)
731 {
732 int num;
733
734 /*
735 ** `HOURSPERDAY * DAYSPERWEEK - 1' allows quasi-Posix rules like
736 ** "M10.4.6/26", which does not conform to Posix,
737 ** but which specifies the equivalent of
738 ** ``02:00 on the first Sunday on or after 23 Oct''.
739 */
740 strp = getnum(strp, &num, 0, HOURSPERDAY * DAYSPERWEEK - 1);
741 if (strp == NULL)
742 return NULL;
743 *secsp = num * (int_fast32_t) SECSPERHOUR;
744 if (*strp == ':') {
745 ++strp;
746 strp = getnum(strp, &num, 0, MINSPERHOUR - 1);
747 if (strp == NULL)
748 return NULL;
749 *secsp += num * SECSPERMIN;
750 if (*strp == ':') {
751 ++strp;
752 /* `SECSPERMIN' allows for leap seconds. */
753 strp = getnum(strp, &num, 0, SECSPERMIN);
754 if (strp == NULL)
755 return NULL;
756 *secsp += num;
757 }
758 }
759 return strp;
760 }
761
762 /*
763 ** Given a pointer into a time zone string, extract an offset, in
764 ** [+-]hh[:mm[:ss]] form, from the string.
765 ** If any error occurs, return NULL.
766 ** Otherwise, return a pointer to the first character not part of the time.
767 */
768
769 static const char *
770 getoffset(const char *strp, int_fast32_t * const offsetp)
771 {
772 int neg = 0;
773
774 if (*strp == '-') {
775 neg = 1;
776 ++strp;
777 } else if (*strp == '+')
778 ++strp;
779 strp = getsecs(strp, offsetp);
780 if (strp == NULL)
781 return NULL; /* illegal time */
782 if (neg)
783 *offsetp = -*offsetp;
784 return strp;
785 }
786
787 /*
788 ** Given a pointer into a time zone string, extract a rule in the form
789 ** date[/time]. See POSIX section 8 for the format of "date" and "time".
790 ** If a valid rule is not found, return NULL.
791 ** Otherwise, return a pointer to the first character not part of the rule.
792 */
793
794 static const char *
795 getrule(const char *strp, struct rule * const rulep)
796 {
797 if (*strp == 'J') {
798 /*
799 ** Julian day.
800 */
801 rulep->r_type = JULIAN_DAY;
802 ++strp;
803 strp = getnum(strp, &rulep->r_day, 1, DAYSPERNYEAR);
804 } else if (*strp == 'M') {
805 /*
806 ** Month, week, day.
807 */
808 rulep->r_type = MONTH_NTH_DAY_OF_WEEK;
809 ++strp;
810 strp = getnum(strp, &rulep->r_mon, 1, MONSPERYEAR);
811 if (strp == NULL)
812 return NULL;
813 if (*strp++ != '.')
814 return NULL;
815 strp = getnum(strp, &rulep->r_week, 1, 5);
816 if (strp == NULL)
817 return NULL;
818 if (*strp++ != '.')
819 return NULL;
820 strp = getnum(strp, &rulep->r_day, 0, DAYSPERWEEK - 1);
821 } else if (is_digit(*strp)) {
822 /*
823 ** Day of year.
824 */
825 rulep->r_type = DAY_OF_YEAR;
826 strp = getnum(strp, &rulep->r_day, 0, DAYSPERLYEAR - 1);
827 } else return NULL; /* invalid format */
828 if (strp == NULL)
829 return NULL;
830 if (*strp == '/') {
831 /*
832 ** Time specified.
833 */
834 ++strp;
835 strp = getoffset(strp, &rulep->r_time);
836 } else rulep->r_time = 2 * SECSPERHOUR; /* default = 2:00:00 */
837 return strp;
838 }
839
840 /*
841 ** Given a year, a rule, and the offset from UT at the time that rule takes
842 ** effect, calculate the year-relative time that rule takes effect.
843 */
844
845 static int_fast32_t
846 transtime(const int year, const struct rule * const rulep,
847 const int_fast32_t offset)
848 {
849 int leapyear;
850 int_fast32_t value;
851 int i;
852 int d, m1, yy0, yy1, yy2, dow;
853
854 INITIALIZE(value);
855 leapyear = isleap(year);
856 switch (rulep->r_type) {
857
858 case JULIAN_DAY:
859 /*
860 ** Jn - Julian day, 1 == January 1, 60 == March 1 even in leap
861 ** years.
862 ** In non-leap years, or if the day number is 59 or less, just
863 ** add SECSPERDAY times the day number-1 to the time of
864 ** January 1, midnight, to get the day.
865 */
866 value = (rulep->r_day - 1) * SECSPERDAY;
867 if (leapyear && rulep->r_day >= 60)
868 value += SECSPERDAY;
869 break;
870
871 case DAY_OF_YEAR:
872 /*
873 ** n - day of year.
874 ** Just add SECSPERDAY times the day number to the time of
875 ** January 1, midnight, to get the day.
876 */
877 value = rulep->r_day * SECSPERDAY;
878 break;
879
880 case MONTH_NTH_DAY_OF_WEEK:
881 /*
882 ** Mm.n.d - nth "dth day" of month m.
883 */
884
885 /*
886 ** Use Zeller's Congruence to get day-of-week of first day of
887 ** month.
888 */
889 m1 = (rulep->r_mon + 9) % 12 + 1;
890 yy0 = (rulep->r_mon <= 2) ? (year - 1) : year;
891 yy1 = yy0 / 100;
892 yy2 = yy0 % 100;
893 dow = ((26 * m1 - 2) / 10 +
894 1 + yy2 + yy2 / 4 + yy1 / 4 - 2 * yy1) % 7;
895 if (dow < 0)
896 dow += DAYSPERWEEK;
897
898 /*
899 ** "dow" is the day-of-week of the first day of the month. Get
900 ** the day-of-month (zero-origin) of the first "dow" day of the
901 ** month.
902 */
903 d = rulep->r_day - dow;
904 if (d < 0)
905 d += DAYSPERWEEK;
906 for (i = 1; i < rulep->r_week; ++i) {
907 if (d + DAYSPERWEEK >=
908 mon_lengths[leapyear][rulep->r_mon - 1])
909 break;
910 d += DAYSPERWEEK;
911 }
912
913 /*
914 ** "d" is the day-of-month (zero-origin) of the day we want.
915 */
916 value = d * SECSPERDAY;
917 for (i = 0; i < rulep->r_mon - 1; ++i)
918 value += mon_lengths[leapyear][i] * SECSPERDAY;
919 break;
920 }
921
922 /*
923 ** "value" is the year-relative time of 00:00:00 UT on the day in
924 ** question. To get the year-relative time of the specified local
925 ** time on that day, add the transition time and the current offset
926 ** from UT.
927 */
928 return value + rulep->r_time + offset;
929 }
930
931 /*
932 ** Given a POSIX section 8-style TZ string, fill in the rule tables as
933 ** appropriate.
934 */
935
936 static int
937 tzparse(const char *name, struct state * const sp, const int lastditch)
938 {
939 const char * stdname;
940 const char * dstname;
941 size_t stdlen;
942 size_t dstlen;
943 int_fast32_t stdoffset;
944 int_fast32_t dstoffset;
945 char * cp;
946 int load_result;
947 static struct ttinfo zttinfo;
948
949 INITIALIZE(dstname);
950 stdname = name;
951 if (lastditch) {
952 stdlen = strlen(name); /* length of standard zone name */
953 name += stdlen;
954 if (stdlen >= sizeof sp->chars)
955 stdlen = (sizeof sp->chars) - 1;
956 stdoffset = 0;
957 } else {
958 if (*name == '<') {
959 name++;
960 stdname = name;
961 name = getqzname(name, '>');
962 if (*name != '>')
963 return (-1);
964 stdlen = name - stdname;
965 name++;
966 } else {
967 name = getzname(name);
968 stdlen = name - stdname;
969 }
970 if (*name == '\0')
971 return -1;
972 name = getoffset(name, &stdoffset);
973 if (name == NULL)
974 return -1;
975 }
976 load_result = tzload(TZDEFRULES, sp, FALSE);
977 if (load_result != 0)
978 sp->leapcnt = 0; /* so, we're off a little */
979 if (*name != '\0') {
980 if (*name == '<') {
981 dstname = ++name;
982 name = getqzname(name, '>');
983 if (*name != '>')
984 return -1;
985 dstlen = name - dstname;
986 name++;
987 } else {
988 dstname = name;
989 name = getzname(name);
990 dstlen = name - dstname; /* length of DST zone name */
991 }
992 if (*name != '\0' && *name != ',' && *name != ';') {
993 name = getoffset(name, &dstoffset);
994 if (name == NULL)
995 return -1;
996 } else dstoffset = stdoffset - SECSPERHOUR;
997 if (*name == '\0' && load_result != 0)
998 name = TZDEFRULESTRING;
999 if (*name == ',' || *name == ';') {
1000 struct rule start;
1001 struct rule end;
1002 int year;
1003 int yearlim;
1004 int timecnt;
1005 time_t janfirst;
1006
1007 ++name;
1008 if ((name = getrule(name, &start)) == NULL)
1009 return -1;
1010 if (*name++ != ',')
1011 return -1;
1012 if ((name = getrule(name, &end)) == NULL)
1013 return -1;
1014 if (*name != '\0')
1015 return -1;
1016 sp->typecnt = 2; /* standard time and DST */
1017 /*
1018 ** Two transitions per year, from EPOCH_YEAR forward.
1019 */
1020 sp->ttis[0] = sp->ttis[1] = zttinfo;
1021 sp->ttis[0].tt_gmtoff = -dstoffset;
1022 sp->ttis[0].tt_isdst = 1;
1023 sp->ttis[0].tt_abbrind = stdlen + 1;
1024 sp->ttis[1].tt_gmtoff = -stdoffset;
1025 sp->ttis[1].tt_isdst = 0;
1026 sp->ttis[1].tt_abbrind = 0;
1027 timecnt = 0;
1028 janfirst = 0;
1029 yearlim = EPOCH_YEAR + YEARSPERREPEAT;
1030 for (year = EPOCH_YEAR; year < yearlim; year++) {
1031 int_fast32_t
1032 starttime = transtime(year, &start, stdoffset),
1033 endtime = transtime(year, &end, dstoffset);
1034 int_fast32_t
1035 yearsecs = (year_lengths[isleap(year)]
1036 * SECSPERDAY);
1037 int reversed = endtime < starttime;
1038 if (reversed) {
1039 int_fast32_t swap = starttime;
1040 starttime = endtime;
1041 endtime = swap;
1042 }
1043 if (reversed
1044 || (starttime < endtime
1045 && (endtime - starttime
1046 < (yearsecs
1047 + (stdoffset - dstoffset))))) {
1048 if (TZ_MAX_TIMES - 2 < timecnt)
1049 break;
1050 yearlim = year + YEARSPERREPEAT + 1;
1051 sp->ats[timecnt] = janfirst;
1052 if (increment_overflow_time
1053 (&sp->ats[timecnt], starttime))
1054 break;
1055 sp->types[timecnt++] = reversed;
1056 sp->ats[timecnt] = janfirst;
1057 if (increment_overflow_time
1058 (&sp->ats[timecnt], endtime))
1059 break;
1060 sp->types[timecnt++] = !reversed;
1061 }
1062 if (increment_overflow_time(&janfirst, yearsecs))
1063 break;
1064 }
1065 sp->timecnt = timecnt;
1066 if (!timecnt)
1067 sp->typecnt = 1; /* Perpetual DST. */
1068 } else {
1069 int_fast32_t theirstdoffset;
1070 int_fast32_t theirdstoffset;
1071 int_fast32_t theiroffset;
1072 int isdst;
1073 int i;
1074 int j;
1075
1076 if (*name != '\0')
1077 return -1;
1078 /*
1079 ** Initial values of theirstdoffset and theirdstoffset.
1080 */
1081 theirstdoffset = 0;
1082 for (i = 0; i < sp->timecnt; ++i) {
1083 j = sp->types[i];
1084 if (!sp->ttis[j].tt_isdst) {
1085 theirstdoffset =
1086 -sp->ttis[j].tt_gmtoff;
1087 break;
1088 }
1089 }
1090 theirdstoffset = 0;
1091 for (i = 0; i < sp->timecnt; ++i) {
1092 j = sp->types[i];
1093 if (sp->ttis[j].tt_isdst) {
1094 theirdstoffset =
1095 -sp->ttis[j].tt_gmtoff;
1096 break;
1097 }
1098 }
1099 /*
1100 ** Initially we're assumed to be in standard time.
1101 */
1102 isdst = FALSE;
1103 theiroffset = theirstdoffset;
1104 /*
1105 ** Now juggle transition times and types
1106 ** tracking offsets as you do.
1107 */
1108 for (i = 0; i < sp->timecnt; ++i) {
1109 j = sp->types[i];
1110 sp->types[i] = sp->ttis[j].tt_isdst;
1111 if (sp->ttis[j].tt_ttisgmt) {
1112 /* No adjustment to transition time */
1113 } else {
1114 /*
1115 ** If summer time is in effect, and the
1116 ** transition time was not specified as
1117 ** standard time, add the summer time
1118 ** offset to the transition time;
1119 ** otherwise, add the standard time
1120 ** offset to the transition time.
1121 */
1122 /*
1123 ** Transitions from DST to DDST
1124 ** will effectively disappear since
1125 ** POSIX provides for only one DST
1126 ** offset.
1127 */
1128 if (isdst && !sp->ttis[j].tt_ttisstd) {
1129 sp->ats[i] += dstoffset -
1130 theirdstoffset;
1131 } else {
1132 sp->ats[i] += stdoffset -
1133 theirstdoffset;
1134 }
1135 }
1136 theiroffset = -sp->ttis[j].tt_gmtoff;
1137 if (sp->ttis[j].tt_isdst)
1138 theirdstoffset = theiroffset;
1139 else theirstdoffset = theiroffset;
1140 }
1141 /*
1142 ** Finally, fill in ttis.
1143 */
1144 sp->ttis[0] = sp->ttis[1] = zttinfo;
1145 sp->ttis[0].tt_gmtoff = -stdoffset;
1146 sp->ttis[0].tt_isdst = FALSE;
1147 sp->ttis[0].tt_abbrind = 0;
1148 sp->ttis[1].tt_gmtoff = -dstoffset;
1149 sp->ttis[1].tt_isdst = TRUE;
1150 sp->ttis[1].tt_abbrind = stdlen + 1;
1151 sp->typecnt = 2;
1152 }
1153 } else {
1154 dstlen = 0;
1155 sp->typecnt = 1; /* only standard time */
1156 sp->timecnt = 0;
1157 sp->ttis[0] = zttinfo;
1158 sp->ttis[0].tt_gmtoff = -stdoffset;
1159 sp->ttis[0].tt_isdst = 0;
1160 sp->ttis[0].tt_abbrind = 0;
1161 }
1162 sp->charcnt = stdlen + 1;
1163 if (dstlen != 0)
1164 sp->charcnt += dstlen + 1;
1165 if ((size_t) sp->charcnt > sizeof sp->chars)
1166 return -1;
1167 cp = sp->chars;
1168 strncpy(cp, stdname, stdlen);
1169 cp += stdlen;
1170 *cp++ = '\0';
1171 if (dstlen != 0) {
1172 strncpy(cp, dstname, dstlen);
1173 *(cp + dstlen) = '\0';
1174 }
1175 return 0;
1176 }
1177
1178 static void
1179 gmtload(struct state * const sp)
1180 {
1181 if (tzload(gmt, sp, TRUE) != 0)
1182 tzparse(gmt, sp, TRUE);
1183 }
1184
1185 static void
1186 tzsetwall_basic(int rdlocked)
1187 {
1188 if (!rdlocked)
1189 _RWLOCK_RDLOCK(&lcl_rwlock);
1190 if (lcl_is_set < 0) {
1191 if (!rdlocked)
1192 _RWLOCK_UNLOCK(&lcl_rwlock);
1193 return;
1194 }
1195 _RWLOCK_UNLOCK(&lcl_rwlock);
1196
1197 _RWLOCK_WRLOCK(&lcl_rwlock);
1198 lcl_is_set = -1;
1199
1200 if (tzload(NULL, lclptr, TRUE) != 0)
1201 gmtload(lclptr);
1202 settzname();
1203 _RWLOCK_UNLOCK(&lcl_rwlock);
1204
1205 if (rdlocked)
1206 _RWLOCK_RDLOCK(&lcl_rwlock);
1207 }
1208
1209 void
1210 tzsetwall(void)
1211 {
1212 tzsetwall_basic(0);
1213 }
1214
1215 static void
1216 tzset_basic(int rdlocked)
1217 {
1218 const char * name;
1219
1220 name = getenv("TZ");
1221 if (name == NULL) {
1222 tzsetwall_basic(rdlocked);
1223 return;
1224 }
1225
1226 if (!rdlocked)
1227 _RWLOCK_RDLOCK(&lcl_rwlock);
1228 if (lcl_is_set > 0 && strcmp(lcl_TZname, name) == 0) {
1229 if (!rdlocked)
1230 _RWLOCK_UNLOCK(&lcl_rwlock);
1231 return;
1232 }
1233 _RWLOCK_UNLOCK(&lcl_rwlock);
1234
1235 _RWLOCK_WRLOCK(&lcl_rwlock);
1236 lcl_is_set = strlen(name) < sizeof lcl_TZname;
1237 if (lcl_is_set)
1238 strcpy(lcl_TZname, name);
1239
1240 if (*name == '\0') {
1241 /*
1242 ** User wants it fast rather than right.
1243 */
1244 lclptr->leapcnt = 0; /* so, we're off a little */
1245 lclptr->timecnt = 0;
1246 lclptr->typecnt = 0;
1247 lclptr->ttis[0].tt_isdst = 0;
1248 lclptr->ttis[0].tt_gmtoff = 0;
1249 lclptr->ttis[0].tt_abbrind = 0;
1250 strcpy(lclptr->chars, gmt);
1251 } else if (tzload(name, lclptr, TRUE) != 0)
1252 if (name[0] == ':' || tzparse(name, lclptr, FALSE) != 0)
1253 gmtload(lclptr);
1254 settzname();
1255 _RWLOCK_UNLOCK(&lcl_rwlock);
1256
1257 if (rdlocked)
1258 _RWLOCK_RDLOCK(&lcl_rwlock);
1259 }
1260
1261 void
1262 tzset(void)
1263 {
1264 tzset_basic(0);
1265 }
1266
1267 /*
1268 ** The easy way to behave "as if no library function calls" localtime
1269 ** is to not call it--so we drop its guts into "localsub", which can be
1270 ** freely called. (And no, the PANS doesn't require the above behavior--
1271 ** but it *is* desirable.)
1272 **
1273 ** The unused offset argument is for the benefit of mktime variants.
1274 */
1275
1276 /*ARGSUSED*/
1277 static struct tm *
1278 localsub(const time_t * const timep, const int_fast32_t offset __unused,
1279 struct tm * const tmp)
1280 {
1281 struct state * sp;
1282 const struct ttinfo * ttisp;
1283 int i;
1284 struct tm * result;
1285 const time_t t = *timep;
1286
1287 sp = lclptr;
1288
1289 if ((sp->goback && t < sp->ats[0]) ||
1290 (sp->goahead && t > sp->ats[sp->timecnt - 1])) {
1291 time_t newt = t;
1292 time_t seconds;
1293 time_t years;
1294
1295 if (t < sp->ats[0])
1296 seconds = sp->ats[0] - t;
1297 else seconds = t - sp->ats[sp->timecnt - 1];
1298 --seconds;
1299 years = (seconds / SECSPERREPEAT + 1) * YEARSPERREPEAT;
1300 seconds = years * AVGSECSPERYEAR;
1301 if (t < sp->ats[0])
1302 newt += seconds;
1303 else newt -= seconds;
1304 if (newt < sp->ats[0] ||
1305 newt > sp->ats[sp->timecnt - 1])
1306 return NULL; /* "cannot happen" */
1307 result = localsub(&newt, offset, tmp);
1308 if (result == tmp) {
1309 time_t newy;
1310
1311 newy = tmp->tm_year;
1312 if (t < sp->ats[0])
1313 newy -= years;
1314 else newy += years;
1315 tmp->tm_year = newy;
1316 if (tmp->tm_year != newy)
1317 return NULL;
1318 }
1319 return result;
1320 }
1321 if (sp->timecnt == 0 || t < sp->ats[0]) {
1322 i = sp->defaulttype;
1323 } else {
1324 int lo = 1;
1325 int hi = sp->timecnt;
1326
1327 while (lo < hi) {
1328 int mid = (lo + hi) >> 1;
1329
1330 if (t < sp->ats[mid])
1331 hi = mid;
1332 else lo = mid + 1;
1333 }
1334 i = (int) sp->types[lo - 1];
1335 }
1336 ttisp = &sp->ttis[i];
1337 /*
1338 ** To get (wrong) behavior that's compatible with System V Release 2.0
1339 ** you'd replace the statement below with
1340 ** t += ttisp->tt_gmtoff;
1341 ** timesub(&t, 0L, sp, tmp);
1342 */
1343 result = timesub(&t, ttisp->tt_gmtoff, sp, tmp);
1344 tmp->tm_isdst = ttisp->tt_isdst;
1345 tzname[tmp->tm_isdst] = &sp->chars[ttisp->tt_abbrind];
1346 #ifdef TM_ZONE
1347 tmp->TM_ZONE = &sp->chars[ttisp->tt_abbrind];
1348 #endif /* defined TM_ZONE */
1349 return result;
1350 }
1351
1352 static void
1353 localtime_key_init(void)
1354 {
1355
1356 localtime_key_error = _pthread_key_create(&localtime_key, free);
1357 }
1358
1359 struct tm *
1360 localtime(const time_t * const timep)
1361 {
1362 struct tm *p_tm;
1363
1364 if (__isthreaded != 0) {
1365 _pthread_once(&localtime_once, localtime_key_init);
1366 if (localtime_key_error != 0) {
1367 errno = localtime_key_error;
1368 return(NULL);
1369 }
1370 p_tm = _pthread_getspecific(localtime_key);
1371 if (p_tm == NULL) {
1372 if ((p_tm = (struct tm *)malloc(sizeof(struct tm)))
1373 == NULL)
1374 return(NULL);
1375 _pthread_setspecific(localtime_key, p_tm);
1376 }
1377 _RWLOCK_RDLOCK(&lcl_rwlock);
1378 tzset_basic(1);
1379 localsub(timep, 0L, p_tm);
1380 _RWLOCK_UNLOCK(&lcl_rwlock);
1381 return(p_tm);
1382 } else {
1383 tzset_basic(0);
1384 localsub(timep, 0L, &tm);
1385 return(&tm);
1386 }
1387 }
1388
1389 /*
1390 ** Re-entrant version of localtime.
1391 */
1392
1393 struct tm *
1394 localtime_r(const time_t * const timep, struct tm *tmp)
1395 {
1396 _RWLOCK_RDLOCK(&lcl_rwlock);
1397 tzset_basic(1);
1398 localsub(timep, 0L, tmp);
1399 _RWLOCK_UNLOCK(&lcl_rwlock);
1400 return tmp;
1401 }
1402
1403 static void
1404 gmt_init(void)
1405 {
1406 gmtload(gmtptr);
1407 }
1408
1409 /*
1410 ** gmtsub is to gmtime as localsub is to localtime.
1411 */
1412
1413 static struct tm *
1414 gmtsub(const time_t * const timep, const int_fast32_t offset,
1415 struct tm * const tmp)
1416 {
1417 struct tm * result;
1418
1419 _once(&gmt_once, gmt_init);
1420 result = timesub(timep, offset, gmtptr, tmp);
1421 #ifdef TM_ZONE
1422 /*
1423 ** Could get fancy here and deliver something such as
1424 ** "UT+xxxx" or "UT-xxxx" if offset is non-zero,
1425 ** but this is no time for a treasure hunt.
1426 */
1427 if (offset != 0)
1428 tmp->TM_ZONE = wildabbr;
1429 else
1430 tmp->TM_ZONE = gmtptr->chars;
1431 #endif /* defined TM_ZONE */
1432 return result;
1433 }
1434
1435 static void
1436 gmtime_key_init(void)
1437 {
1438 gmtime_key_error = _pthread_key_create(&gmtime_key, free);
1439 }
1440
1441 struct tm *
1442 gmtime(const time_t * const timep)
1443 {
1444 struct tm *p_tm;
1445
1446 if (__isthreaded != 0) {
1447 _pthread_once(&gmtime_once, gmtime_key_init);
1448 if (gmtime_key_error != 0) {
1449 errno = gmtime_key_error;
1450 return(NULL);
1451 }
1452 /*
1453 * Changed to follow POSIX.1 threads standard, which
1454 * is what BSD currently has.
1455 */
1456 if ((p_tm = _pthread_getspecific(gmtime_key)) == NULL) {
1457 if ((p_tm = (struct tm *)malloc(sizeof(struct tm)))
1458 == NULL) {
1459 return(NULL);
1460 }
1461 _pthread_setspecific(gmtime_key, p_tm);
1462 }
1463 return gmtsub(timep, 0L, p_tm);
1464 } else {
1465 return gmtsub(timep, 0L, &tm);
1466 }
1467 }
1468
1469 /*
1470 * Re-entrant version of gmtime.
1471 */
1472
1473 struct tm *
1474 gmtime_r(const time_t * timep, struct tm * tmp)
1475 {
1476 return gmtsub(timep, 0L, tmp);
1477 }
1478
1479 struct tm *
1480 offtime(const time_t * const timep, const long offset)
1481 {
1482 return gmtsub(timep, offset, &tm);
1483 }
1484
1485 /*
1486 ** Return the number of leap years through the end of the given year
1487 ** where, to make the math easy, the answer for year zero is defined as zero.
1488 */
1489
1490 static int
1491 leaps_thru_end_of(const int y)
1492 {
1493 return (y >= 0) ? (y / 4 - y / 100 + y / 400) :
1494 -(leaps_thru_end_of(-(y + 1)) + 1);
1495 }
1496
1497 static struct tm *
1498 timesub(const time_t * const timep, const int_fast32_t offset,
1499 const struct state * const sp, struct tm * const tmp)
1500 {
1501 const struct lsinfo * lp;
1502 time_t tdays;
1503 int idays; /* unsigned would be so 2003 */
1504 int_fast64_t rem;
1505 int y;
1506 const int * ip;
1507 int_fast64_t corr;
1508 int hit;
1509 int i;
1510
1511 corr = 0;
1512 hit = 0;
1513 i = sp->leapcnt;
1514
1515 while (--i >= 0) {
1516 lp = &sp->lsis[i];
1517 if (*timep >= lp->ls_trans) {
1518 if (*timep == lp->ls_trans) {
1519 hit = ((i == 0 && lp->ls_corr > 0) ||
1520 lp->ls_corr > sp->lsis[i - 1].ls_corr);
1521 if (hit)
1522 while (i > 0 &&
1523 sp->lsis[i].ls_trans ==
1524 sp->lsis[i - 1].ls_trans + 1 &&
1525 sp->lsis[i].ls_corr ==
1526 sp->lsis[i - 1].ls_corr + 1) {
1527 ++hit;
1528 --i;
1529 }
1530 }
1531 corr = lp->ls_corr;
1532 break;
1533 }
1534 }
1535 y = EPOCH_YEAR;
1536 tdays = *timep / SECSPERDAY;
1537 rem = *timep - tdays * SECSPERDAY;
1538 while (tdays < 0 || tdays >= year_lengths[isleap(y)]) {
1539 int newy;
1540 time_t tdelta;
1541 int idelta;
1542 int leapdays;
1543
1544 tdelta = tdays / DAYSPERLYEAR;
1545 if (! ((! TYPE_SIGNED(time_t) || INT_MIN <= tdelta)
1546 && tdelta <= INT_MAX))
1547 return NULL;
1548 idelta = tdelta;
1549 if (idelta == 0)
1550 idelta = (tdays < 0) ? -1 : 1;
1551 newy = y;
1552 if (increment_overflow(&newy, idelta))
1553 return NULL;
1554 leapdays = leaps_thru_end_of(newy - 1) -
1555 leaps_thru_end_of(y - 1);
1556 tdays -= ((time_t) newy - y) * DAYSPERNYEAR;
1557 tdays -= leapdays;
1558 y = newy;
1559 }
1560 {
1561 int_fast32_t seconds;
1562
1563 seconds = tdays * SECSPERDAY;
1564 tdays = seconds / SECSPERDAY;
1565 rem += seconds - tdays * SECSPERDAY;
1566 }
1567 /*
1568 ** Given the range, we can now fearlessly cast...
1569 */
1570 idays = tdays;
1571 rem += offset - corr;
1572 while (rem < 0) {
1573 rem += SECSPERDAY;
1574 --idays;
1575 }
1576 while (rem >= SECSPERDAY) {
1577 rem -= SECSPERDAY;
1578 ++idays;
1579 }
1580 while (idays < 0) {
1581 if (increment_overflow(&y, -1))
1582 return NULL;
1583 idays += year_lengths[isleap(y)];
1584 }
1585 while (idays >= year_lengths[isleap(y)]) {
1586 idays -= year_lengths[isleap(y)];
1587 if (increment_overflow(&y, 1))
1588 return NULL;
1589 }
1590 tmp->tm_year = y;
1591 if (increment_overflow(&tmp->tm_year, -TM_YEAR_BASE))
1592 return NULL;
1593 tmp->tm_yday = idays;
1594 /*
1595 ** The "extra" mods below avoid overflow problems.
1596 */
1597 tmp->tm_wday = EPOCH_WDAY +
1598 ((y - EPOCH_YEAR) % DAYSPERWEEK) *
1599 (DAYSPERNYEAR % DAYSPERWEEK) +
1600 leaps_thru_end_of(y - 1) -
1601 leaps_thru_end_of(EPOCH_YEAR - 1) +
1602 idays;
1603 tmp->tm_wday %= DAYSPERWEEK;
1604 if (tmp->tm_wday < 0)
1605 tmp->tm_wday += DAYSPERWEEK;
1606 tmp->tm_hour = (int) (rem / SECSPERHOUR);
1607 rem %= SECSPERHOUR;
1608 tmp->tm_min = (int) (rem / SECSPERMIN);
1609 /*
1610 ** A positive leap second requires a special
1611 ** representation. This uses "... ??:59:60" et seq.
1612 */
1613 tmp->tm_sec = (int) (rem % SECSPERMIN) + hit;
1614 ip = mon_lengths[isleap(y)];
1615 for (tmp->tm_mon = 0; idays >= ip[tmp->tm_mon]; ++(tmp->tm_mon))
1616 idays -= ip[tmp->tm_mon];
1617 tmp->tm_mday = (int) (idays + 1);
1618 tmp->tm_isdst = 0;
1619 #ifdef TM_GMTOFF
1620 tmp->TM_GMTOFF = offset;
1621 #endif /* defined TM_GMTOFF */
1622 return tmp;
1623 }
1624
1625 char *
1626 ctime(const time_t * const timep)
1627 {
1628 /*
1629 ** Section 4.12.3.2 of X3.159-1989 requires that
1630 ** The ctime function converts the calendar time pointed to by timer
1631 ** to local time in the form of a string. It is equivalent to
1632 ** asctime(localtime(timer))
1633 */
1634 return asctime(localtime(timep));
1635 }
1636
1637 char *
1638 ctime_r(const time_t * const timep, char *buf)
1639 {
1640 struct tm mytm;
1641
1642 return asctime_r(localtime_r(timep, &mytm), buf);
1643 }
1644
1645 /*
1646 ** Adapted from code provided by Robert Elz, who writes:
1647 ** The "best" way to do mktime I think is based on an idea of Bob
1648 ** Kridle's (so its said...) from a long time ago.
1649 ** It does a binary search of the time_t space. Since time_t's are
1650 ** just 32 bits, its a max of 32 iterations (even at 64 bits it
1651 ** would still be very reasonable).
1652 */
1653
1654 #ifndef WRONG
1655 #define WRONG (-1)
1656 #endif /* !defined WRONG */
1657
1658 /*
1659 ** Normalize logic courtesy Paul Eggert.
1660 */
1661
1662 static int
1663 increment_overflow(int * const ip, int j)
1664 {
1665 int const i = *ip;
1666
1667 /*
1668 ** If i >= 0 there can only be overflow if i + j > INT_MAX
1669 ** or if j > INT_MAX - i; given i >= 0, INT_MAX - i cannot overflow.
1670 ** If i < 0 there can only be overflow if i + j < INT_MIN
1671 ** or if j < INT_MIN - i; given i < 0, INT_MIN - i cannot overflow.
1672 */
1673 if ((i >= 0) ? (j > INT_MAX - i) : (j < INT_MIN - i))
1674 return TRUE;
1675 *ip += j;
1676 return FALSE;
1677 }
1678
1679 static int
1680 increment_overflow32(int_fast32_t * const lp, int const m)
1681 {
1682 int_fast32_t const l = *lp;
1683
1684 if ((l >= 0) ? (m > INT_FAST32_MAX - l) : (m < INT_FAST32_MIN - l))
1685 return TRUE;
1686 *lp += m;
1687 return FALSE;
1688 }
1689
1690 static int
1691 increment_overflow_time(time_t *tp, int_fast32_t j)
1692 {
1693 /*
1694 ** This is like
1695 ** 'if (! (time_t_min <= *tp + j && *tp + j <= time_t_max)) ...',
1696 ** except that it does the right thing even if *tp + j would overflow.
1697 */
1698 if (! (j < 0
1699 ? (TYPE_SIGNED(time_t) ? time_t_min - j <= *tp : -1 - j < *tp)
1700 : *tp <= time_t_max - j))
1701 return TRUE;
1702 *tp += j;
1703 return FALSE;
1704 }
1705
1706 static int
1707 normalize_overflow(int * const tensptr, int * const unitsptr, const int base)
1708 {
1709 int tensdelta;
1710
1711 tensdelta = (*unitsptr >= 0) ?
1712 (*unitsptr / base) :
1713 (-1 - (-1 - *unitsptr) / base);
1714 *unitsptr -= tensdelta * base;
1715 return increment_overflow(tensptr, tensdelta);
1716 }
1717
1718 static int
1719 normalize_overflow32(int_fast32_t * const tensptr, int * const unitsptr,
1720 const int base)
1721 {
1722 int tensdelta;
1723
1724 tensdelta = (*unitsptr >= 0) ?
1725 (*unitsptr / base) :
1726 (-1 - (-1 - *unitsptr) / base);
1727 *unitsptr -= tensdelta * base;
1728 return increment_overflow32(tensptr, tensdelta);
1729 }
1730
1731 static int
1732 tmcomp(const struct tm * const atmp, const struct tm * const btmp)
1733 {
1734 int result;
1735
1736 if (atmp->tm_year != btmp->tm_year)
1737 return atmp->tm_year < btmp->tm_year ? -1 : 1;
1738 if ((result = (atmp->tm_mon - btmp->tm_mon)) == 0 &&
1739 (result = (atmp->tm_mday - btmp->tm_mday)) == 0 &&
1740 (result = (atmp->tm_hour - btmp->tm_hour)) == 0 &&
1741 (result = (atmp->tm_min - btmp->tm_min)) == 0)
1742 result = atmp->tm_sec - btmp->tm_sec;
1743 return result;
1744 }
1745
1746 static time_t
1747 time2sub(struct tm * const tmp,
1748 struct tm * (* const funcp)(const time_t *, int_fast32_t, struct tm *),
1749 const int_fast32_t offset, int * const okayp, const int do_norm_secs)
1750 {
1751 const struct state * sp;
1752 int dir;
1753 int i, j;
1754 int saved_seconds;
1755 int_fast32_t li;
1756 time_t lo;
1757 time_t hi;
1758 int_fast32_t y;
1759 time_t newt;
1760 time_t t;
1761 struct tm yourtm, mytm;
1762
1763 *okayp = FALSE;
1764 yourtm = *tmp;
1765 if (do_norm_secs) {
1766 if (normalize_overflow(&yourtm.tm_min, &yourtm.tm_sec,
1767 SECSPERMIN))
1768 return WRONG;
1769 }
1770 if (normalize_overflow(&yourtm.tm_hour, &yourtm.tm_min, MINSPERHOUR))
1771 return WRONG;
1772 if (normalize_overflow(&yourtm.tm_mday, &yourtm.tm_hour, HOURSPERDAY))
1773 return WRONG;
1774 y = yourtm.tm_year;
1775 if (normalize_overflow32(&y, &yourtm.tm_mon, MONSPERYEAR))
1776 return WRONG;
1777 /*
1778 ** Turn y into an actual year number for now.
1779 ** It is converted back to an offset from TM_YEAR_BASE later.
1780 */
1781 if (increment_overflow32(&y, TM_YEAR_BASE))
1782 return WRONG;
1783 while (yourtm.tm_mday <= 0) {
1784 if (increment_overflow32(&y, -1))
1785 return WRONG;
1786 li = y + (1 < yourtm.tm_mon);
1787 yourtm.tm_mday += year_lengths[isleap(li)];
1788 }
1789 while (yourtm.tm_mday > DAYSPERLYEAR) {
1790 li = y + (1 < yourtm.tm_mon);
1791 yourtm.tm_mday -= year_lengths[isleap(li)];
1792 if (increment_overflow32(&y, 1))
1793 return WRONG;
1794 }
1795 for ( ; ; ) {
1796 i = mon_lengths[isleap(y)][yourtm.tm_mon];
1797 if (yourtm.tm_mday <= i)
1798 break;
1799 yourtm.tm_mday -= i;
1800 if (++yourtm.tm_mon >= MONSPERYEAR) {
1801 yourtm.tm_mon = 0;
1802 if (increment_overflow32(&y, 1))
1803 return WRONG;
1804 }
1805 }
1806 if (increment_overflow32(&y, -TM_YEAR_BASE))
1807 return WRONG;
1808 yourtm.tm_year = y;
1809 if (yourtm.tm_year != y)
1810 return WRONG;
1811 if (yourtm.tm_sec >= 0 && yourtm.tm_sec < SECSPERMIN)
1812 saved_seconds = 0;
1813 else if (y + TM_YEAR_BASE < EPOCH_YEAR) {
1814 /*
1815 ** We can't set tm_sec to 0, because that might push the
1816 ** time below the minimum representable time.
1817 ** Set tm_sec to 59 instead.
1818 ** This assumes that the minimum representable time is
1819 ** not in the same minute that a leap second was deleted from,
1820 ** which is a safer assumption than using 58 would be.
1821 */
1822 if (increment_overflow(&yourtm.tm_sec, 1 - SECSPERMIN))
1823 return WRONG;
1824 saved_seconds = yourtm.tm_sec;
1825 yourtm.tm_sec = SECSPERMIN - 1;
1826 } else {
1827 saved_seconds = yourtm.tm_sec;
1828 yourtm.tm_sec = 0;
1829 }
1830 /*
1831 ** Do a binary search (this works whatever time_t's type is).
1832 */
1833 if (!TYPE_SIGNED(time_t)) {
1834 lo = 0;
1835 hi = lo - 1;
1836 } else {
1837 lo = 1;
1838 for (i = 0; i < (int) TYPE_BIT(time_t) - 1; ++i)
1839 lo *= 2;
1840 hi = -(lo + 1);
1841 }
1842 for ( ; ; ) {
1843 t = lo / 2 + hi / 2;
1844 if (t < lo)
1845 t = lo;
1846 else if (t > hi)
1847 t = hi;
1848 if ((*funcp)(&t, offset, &mytm) == NULL) {
1849 /*
1850 ** Assume that t is too extreme to be represented in
1851 ** a struct tm; arrange things so that it is less
1852 ** extreme on the next pass.
1853 */
1854 dir = (t > 0) ? 1 : -1;
1855 } else dir = tmcomp(&mytm, &yourtm);
1856 if (dir != 0) {
1857 if (t == lo) {
1858 if (t == time_t_max)
1859 return WRONG;
1860 ++t;
1861 ++lo;
1862 } else if (t == hi) {
1863 if (t == time_t_min)
1864 return WRONG;
1865 --t;
1866 --hi;
1867 }
1868 if (lo > hi)
1869 return WRONG;
1870 if (dir > 0)
1871 hi = t;
1872 else lo = t;
1873 continue;
1874 }
1875 if (yourtm.tm_isdst < 0 || mytm.tm_isdst == yourtm.tm_isdst)
1876 break;
1877 /*
1878 ** Right time, wrong type.
1879 ** Hunt for right time, right type.
1880 ** It's okay to guess wrong since the guess
1881 ** gets checked.
1882 */
1883 sp = (const struct state *)
1884 ((funcp == localsub) ? lclptr : gmtptr);
1885
1886 for (i = sp->typecnt - 1; i >= 0; --i) {
1887 if (sp->ttis[i].tt_isdst != yourtm.tm_isdst)
1888 continue;
1889 for (j = sp->typecnt - 1; j >= 0; --j) {
1890 if (sp->ttis[j].tt_isdst == yourtm.tm_isdst)
1891 continue;
1892 newt = t + sp->ttis[j].tt_gmtoff -
1893 sp->ttis[i].tt_gmtoff;
1894 if ((*funcp)(&newt, offset, &mytm) == NULL)
1895 continue;
1896 if (tmcomp(&mytm, &yourtm) != 0)
1897 continue;
1898 if (mytm.tm_isdst != yourtm.tm_isdst)
1899 continue;
1900 /*
1901 ** We have a match.
1902 */
1903 t = newt;
1904 goto label;
1905 }
1906 }
1907 return WRONG;
1908 }
1909 label:
1910 newt = t + saved_seconds;
1911 if ((newt < t) != (saved_seconds < 0))
1912 return WRONG;
1913 t = newt;
1914 if ((*funcp)(&t, offset, tmp))
1915 *okayp = TRUE;
1916 return t;
1917 }
1918
1919 static time_t
1920 time2(struct tm * const tmp,
1921 struct tm * (* const funcp)(const time_t *, int_fast32_t, struct tm *),
1922 const int_fast32_t offset, int * const okayp)
1923 {
1924 time_t t;
1925
1926 /*
1927 ** First try without normalization of seconds
1928 ** (in case tm_sec contains a value associated with a leap second).
1929 ** If that fails, try with normalization of seconds.
1930 */
1931 t = time2sub(tmp, funcp, offset, okayp, FALSE);
1932 return *okayp ? t : time2sub(tmp, funcp, offset, okayp, TRUE);
1933 }
1934
1935 static time_t
1936 time1(struct tm * const tmp,
1937 struct tm * (* const funcp)(const time_t *, int_fast32_t, struct tm *),
1938 const int_fast32_t offset)
1939 {
1940 time_t t;
1941 const struct state * sp;
1942 int samei, otheri;
1943 int sameind, otherind;
1944 int i;
1945 int nseen;
1946 int seen[TZ_MAX_TYPES];
1947 int types[TZ_MAX_TYPES];
1948 int okay;
1949
1950 if (tmp == NULL) {
1951 errno = EINVAL;
1952 return WRONG;
1953 }
1954 if (tmp->tm_isdst > 1)
1955 tmp->tm_isdst = 1;
1956 t = time2(tmp, funcp, offset, &okay);
1957
1958 /*
1959 ** PCTS code courtesy Grant Sullivan.
1960 */
1961 if (okay)
1962 return t;
1963 if (tmp->tm_isdst < 0)
1964 tmp->tm_isdst = 0; /* reset to std and try again */
1965
1966 /*
1967 ** We're supposed to assume that somebody took a time of one type
1968 ** and did some math on it that yielded a "struct tm" that's bad.
1969 ** We try to divine the type they started from and adjust to the
1970 ** type they need.
1971 */
1972 sp = (const struct state *) ((funcp == localsub) ? lclptr : gmtptr);
1973
1974 for (i = 0; i < sp->typecnt; ++i)
1975 seen[i] = FALSE;
1976 nseen = 0;
1977 for (i = sp->timecnt - 1; i >= 0; --i)
1978 if (!seen[sp->types[i]]) {
1979 seen[sp->types[i]] = TRUE;
1980 types[nseen++] = sp->types[i];
1981 }
1982 for (sameind = 0; sameind < nseen; ++sameind) {
1983 samei = types[sameind];
1984 if (sp->ttis[samei].tt_isdst != tmp->tm_isdst)
1985 continue;
1986 for (otherind = 0; otherind < nseen; ++otherind) {
1987 otheri = types[otherind];
1988 if (sp->ttis[otheri].tt_isdst == tmp->tm_isdst)
1989 continue;
1990 tmp->tm_sec += sp->ttis[otheri].tt_gmtoff -
1991 sp->ttis[samei].tt_gmtoff;
1992 tmp->tm_isdst = !tmp->tm_isdst;
1993 t = time2(tmp, funcp, offset, &okay);
1994 if (okay)
1995 return t;
1996 tmp->tm_sec -= sp->ttis[otheri].tt_gmtoff -
1997 sp->ttis[samei].tt_gmtoff;
1998 tmp->tm_isdst = !tmp->tm_isdst;
1999 }
2000 }
2001 return WRONG;
2002 }
2003
2004 time_t
2005 mktime(struct tm * const tmp)
2006 {
2007 time_t mktime_return_value;
2008 _RWLOCK_RDLOCK(&lcl_rwlock);
2009 tzset_basic(1);
2010 mktime_return_value = time1(tmp, localsub, 0L);
2011 _RWLOCK_UNLOCK(&lcl_rwlock);
2012 return(mktime_return_value);
2013 }
2014
2015 time_t
2016 timelocal(struct tm * const tmp)
2017 {
2018 if (tmp != NULL)
2019 tmp->tm_isdst = -1; /* in case it wasn't initialized */
2020 return mktime(tmp);
2021 }
2022
2023 time_t
2024 timegm(struct tm * const tmp)
2025 {
2026 if (tmp != NULL)
2027 tmp->tm_isdst = 0;
2028 return time1(tmp, gmtsub, 0L);
2029 }
2030
2031 time_t
2032 timeoff(struct tm * const tmp, const long offset)
2033 {
2034 if (tmp != NULL)
2035 tmp->tm_isdst = 0;
2036 return time1(tmp, gmtsub, offset);
2037 }
2038
2039 /*
2040 ** XXX--is the below the right way to conditionalize??
2041 */
2042
2043 /*
2044 ** IEEE Std 1003.1-1988 (POSIX) legislates that 536457599
2045 ** shall correspond to "Wed Dec 31 23:59:59 UTC 1986", which
2046 ** is not the case if we are accounting for leap seconds.
2047 ** So, we provide the following conversion routines for use
2048 ** when exchanging timestamps with POSIX conforming systems.
2049 */
2050
2051 static int_fast64_t
2052 leapcorr(time_t *timep)
2053 {
2054 struct state * sp;
2055 struct lsinfo * lp;
2056 int i;
2057
2058 sp = lclptr;
2059 i = sp->leapcnt;
2060 while (--i >= 0) {
2061 lp = &sp->lsis[i];
2062 if (*timep >= lp->ls_trans)
2063 return lp->ls_corr;
2064 }
2065 return 0;
2066 }
2067
2068 time_t
2069 time2posix(time_t t)
2070 {
2071 tzset();
2072 return t - leapcorr(&t);
2073 }
2074
2075 time_t
2076 posix2time(time_t t)
2077 {
2078 time_t x;
2079 time_t y;
2080
2081 tzset();
2082 /*
2083 ** For a positive leap second hit, the result
2084 ** is not unique. For a negative leap second
2085 ** hit, the corresponding time doesn't exist,
2086 ** so we return an adjacent second.
2087 */
2088 x = t + leapcorr(&t);
2089 y = x - leapcorr(&x);
2090 if (y < t) {
2091 do {
2092 x++;
2093 y = x - leapcorr(&x);
2094 } while (y < t);
2095 if (t != y)
2096 return x - 1;
2097 } else if (y > t) {
2098 do {
2099 --x;
2100 y = x - leapcorr(&x);
2101 } while (y > t);
2102 if (t != y)
2103 return x + 1;
2104 }
2105 return x;
2106 }
DragonFly BSD