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kernel - Fix pmap deactivate/reactivation race.
[dragonfly.git] / lib / libc / stdtime / localtime.c
blobed2a7286a20268680e0ab07f50b6ca6da63fc716
1 /*
2 ** This file is in the public domain, so clarified as of
3 ** 1996-06-05 by Arthur David Olson.
4 **
5 ** @(#)localtime.c 8.13
6 ** $FreeBSD: src/lib/libc/stdtime/localtime.c,v 1.25.2.2 2002/08/13 16:08:07 bmilekic Exp $
7 */
8
9 /*
10 ** Leap second handling from Bradley White.
11 ** POSIX-style TZ environment variable handling from Guy Harris.
12 */
13
14 /*LINTLIBRARY*/
15
16 #include "namespace.h"
17 #include <sys/types.h>
18 #include <sys/stat.h>
19
20 #include <fcntl.h>
21 #include <float.h> /* for FLT_MAX and DBL_MAX */
22 #include <time.h>
23 #include <pthread.h>
24 #include "private.h"
25 #include <un-namespace.h>
26
27 #include "tzfile.h"
28
29 #include "libc_private.h"
30
31 #define _MUTEX_LOCK(x) if (__isthreaded) _pthread_mutex_lock(x)
32 #define _MUTEX_UNLOCK(x) if (__isthreaded) _pthread_mutex_unlock(x)
33
34 #define _RWLOCK_RDLOCK(x) \
35 do { \
36 if (__isthreaded) _pthread_rwlock_rdlock(x); \
37 } while (0)
38
39 #define _RWLOCK_WRLOCK(x) \
40 do { \
41 if (__isthreaded) _pthread_rwlock_wrlock(x); \
42 } while (0)
43
44 #define _RWLOCK_UNLOCK(x) \
45 do { \
46 if (__isthreaded) _pthread_rwlock_unlock(x); \
47 } while (0)
48
49 #ifndef TZ_ABBR_MAX_LEN
50 #define TZ_ABBR_MAX_LEN 16
51 #endif /* !defined TZ_ABBR_MAX_LEN */
52
53 #ifndef TZ_ABBR_CHAR_SET
54 #define TZ_ABBR_CHAR_SET \
55 "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789 :+-._"
56 #endif /* !defined TZ_ABBR_CHAR_SET */
57
58 #ifndef TZ_ABBR_ERR_CHAR
59 #define TZ_ABBR_ERR_CHAR '_'
60 #endif /* !defined TZ_ABBR_ERR_CHAR */
61
62 /*
63 ** Someone might make incorrect use of a time zone abbreviation:
64 ** 1. They might reference tzname[0] before calling tzset (explicitly
65 ** or implicitly).
66 ** 2. They might reference tzname[1] before calling tzset (explicitly
67 ** or implicitly).
68 ** 3. They might reference tzname[1] after setting to a time zone
69 ** in which Daylight Saving Time is never observed.
70 ** 4. They might reference tzname[0] after setting to a time zone
71 ** in which Standard Time is never observed.
72 ** 5. They might reference tm.TM_ZONE after calling offtime.
73 ** What's best to do in the above cases is open to debate;
74 ** for now, we just set things up so that in any of the five cases
75 ** WILDABBR is used. Another possibility: initialize tzname[0] to the
76 ** string "tzname[0] used before set", and similarly for the other cases.
77 ** And another: initialize tzname[0] to "ERA", with an explanation in the
78 ** manual page of what this "time zone abbreviation" means (doing this so
79 ** that tzname[0] has the "normal" length of three characters).
80 */
81 #define WILDABBR " "
82
83 static char wildabbr[] = WILDABBR;
84
85 static const char gmt[] = "UTC";
86
87 /*
88 ** The DST rules to use if TZ has no rules and we can't load TZDEFRULES.
89 ** We default to US rules as of 1999-08-17.
90 ** POSIX 1003.1 section 8.1.1 says that the default DST rules are
91 ** implementation dependent; for historical reasons, US rules are a
92 ** common default.
93 */
94 #ifndef TZDEFRULESTRING
95 #define TZDEFRULESTRING ",M4.1.0,M10.5.0"
96 #endif /* !defined TZDEFDST */
97
98 struct ttinfo { /* time type information */
99 long tt_gmtoff; /* UTC offset in seconds */
100 int tt_isdst; /* used to set tm_isdst */
101 int tt_abbrind; /* abbreviation list index */
102 int tt_ttisstd; /* TRUE if transition is std time */
103 int tt_ttisgmt; /* TRUE if transition is UTC */
104 };
105
106 struct lsinfo { /* leap second information */
107 time_t ls_trans; /* transition time */
108 long ls_corr; /* correction to apply */
109 };
110
111 #define BIGGEST(a, b) (((a) > (b)) ? (a) : (b))
112
113 #ifdef TZNAME_MAX
114 #define MY_TZNAME_MAX TZNAME_MAX
115 #endif /* defined TZNAME_MAX */
116 #ifndef TZNAME_MAX
117 #define MY_TZNAME_MAX 255
118 #endif /* !defined TZNAME_MAX */
119
120 struct state {
121 int leapcnt;
122 int timecnt;
123 int typecnt;
124 int charcnt;
125 int goback;
126 int goahead;
127 time_t ats[TZ_MAX_TIMES];
128 unsigned char types[TZ_MAX_TIMES];
129 struct ttinfo ttis[TZ_MAX_TYPES];
130 char chars[BIGGEST(BIGGEST(TZ_MAX_CHARS + 1, sizeof gmt),
131 (2 * (MY_TZNAME_MAX + 1)))];
132 struct lsinfo lsis[TZ_MAX_LEAPS];
133 };
134
135 struct rule {
136 int r_type; /* type of rule--see below */
137 int r_day; /* day number of rule */
138 int r_week; /* week number of rule */
139 int r_mon; /* month number of rule */
140 long r_time; /* transition time of rule */
141 };
142
143 #define JULIAN_DAY 0 /* Jn - Julian day */
144 #define DAY_OF_YEAR 1 /* n - day of year */
145 #define MONTH_NTH_DAY_OF_WEEK 2 /* Mm.n.d - month, week, day of week */
146
147 /*
148 ** Prototypes for static functions.
149 */
150
151 static long detzcode(const char * codep);
152 static time_t detzcode64(const char * codep);
153 static int differ_by_repeat(time_t t1, time_t t0);
154 static const char * getzname(const char * strp);
155 static const char * getqzname(const char * strp, const int delim);
156 static const char * getnum(const char * strp, int * nump, int min,
157 int max);
158 static const char * getsecs(const char * strp, long * secsp);
159 static const char * getoffset(const char * strp, long * offsetp);
160 static const char * getrule(const char * strp, struct rule * rulep);
161 static void gmtload(struct state * sp);
162 static struct tm * gmtsub(const time_t * timep, long offset,
163 struct tm * tmp);
164 static struct tm * localsub(const time_t * timep, long offset,
165 struct tm * tmp);
166 static int increment_overflow(int * number, int delta);
167 static int leaps_thru_end_of(int y);
168 static int long_increment_overflow(long * number, int delta);
169 static int long_normalize_overflow(long * 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 long, struct tm *),
177 long offset);
178 static time_t time2(struct tm *tmp,
179 struct tm * (*funcp)(const time_t *,
180 long, struct tm*),
181 long offset, int * okayp);
182 static time_t time2sub(struct tm *tmp,
183 struct tm * (*funcp)(const time_t *,
184 long, struct tm*),
185 long offset, int * okayp, int do_norm_secs);
186 static struct tm * timesub(const time_t * timep, long offset,
187 const struct state * sp, struct tm * tmp);
188 static int tmcomp(const struct tm * atmp,
189 const struct tm * btmp);
190 static time_t transtime(time_t janfirst, int year,
191 const struct rule * rulep, long offset);
192 static int typesequiv(const 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 int gmt_is_set;
210 static pthread_rwlock_t lcl_rwlock = PTHREAD_RWLOCK_INITIALIZER;
211 static pthread_mutex_t gmt_mutex = PTHREAD_MUTEX_INITIALIZER;
212
213 char * tzname[2] = {
214 wildabbr,
215 wildabbr
216 };
217
218 /*
219 ** Section 4.12.3 of X3.159-1989 requires that
220 ** Except for the strftime function, these functions [asctime,
221 ** ctime, gmtime, localtime] return values in one of two static
222 ** objects: a broken-down time structure and an array of char.
223 ** Thanks to Paul Eggert for noting this.
224 */
225
226 static struct tm tm;
227
228 time_t timezone = 0;
229 int daylight = 0;
230
231 static long
232 detzcode(const char * const codep)
233 {
234 long result;
235 int i;
236
237 result = (codep[0] & 0x80) ? ~0L : 0;
238 for (i = 0; i < 4; ++i)
239 result = (result << 8) | (codep[i] & 0xff);
240 return result;
241 }
242
243 static time_t
244 detzcode64(const char * const codep)
245 {
246 time_t result;
247 int i;
248
249 result = (codep[0] & 0x80) ? (~(int_fast64_t) 0) : 0;
250 for (i = 0; i < 8; ++i)
251 result = result * 256 + (codep[i] & 0xff);
252 return result;
253 }
254
255 static void
256 settzname(void)
257 {
258 struct state * const sp = lclptr;
259 int i;
260
261 tzname[0] = wildabbr;
262 tzname[1] = wildabbr;
263 daylight = 0;
264 timezone = 0;
265
266 for (i = 0; i < sp->typecnt; ++i) {
267 const struct ttinfo * const ttisp = &sp->ttis[i];
268
269 tzname[ttisp->tt_isdst] =
270 &sp->chars[ttisp->tt_abbrind];
271 if (ttisp->tt_isdst)
272 daylight = 1;
273 if (i == 0 || !ttisp->tt_isdst)
274 timezone = -(ttisp->tt_gmtoff);
275 }
276 /*
277 ** And to get the latest zone names into tzname. . .
278 */
279 for (i = 0; i < sp->timecnt; ++i) {
280 const struct ttinfo * const ttisp =
281 &sp->ttis[
282 sp->types[i]];
283
284 tzname[ttisp->tt_isdst] =
285 &sp->chars[ttisp->tt_abbrind];
286 }
287 /*
288 ** Finally, scrub the abbreviations.
289 ** First, replace bogus characters.
290 */
291 for (i = 0; i < sp->charcnt; ++i)
292 if (strchr(TZ_ABBR_CHAR_SET, sp->chars[i]) == NULL)
293 sp->chars[i] = TZ_ABBR_ERR_CHAR;
294 /*
295 ** Second, truncate long abbreviations.
296 */
297 for (i = 0; i < sp->typecnt; ++i) {
298 const struct ttinfo * const ttisp = &sp->ttis[i];
299 char * cp = &sp->chars[ttisp->tt_abbrind];
300
301 if (strlen(cp) > TZ_ABBR_MAX_LEN &&
302 strcmp(cp, GRANDPARENTED) != 0)
303 *(cp + TZ_ABBR_MAX_LEN) = '\0';
304 }
305 }
306
307 static int
308 differ_by_repeat(const time_t t1, const time_t t0)
309 {
310 int_fast64_t _t0 = t0;
311 int_fast64_t _t1 = t1;
312
313 if (TYPE_INTEGRAL(time_t) &&
314 TYPE_BIT(time_t) - TYPE_SIGNED(time_t) < SECSPERREPEAT_BITS)
315 return 0;
316 return _t1 - _t0 == SECSPERREPEAT;
317 }
318
319 static int
320 tzload(const char *name, struct state * const sp, const int doextend)
321 {
322 const char * p;
323 int i;
324 int fid;
325 int stored;
326 int nread;
327 union {
328 struct tzhead tzhead;
329 char buf[2 * sizeof(struct tzhead) +
330 2 * sizeof *sp +
331 4 * TZ_MAX_TIMES];
332 } u;
333
334 sp->goback = sp->goahead = FALSE;
335
336 /* XXX The following is from OpenBSD, and I'm not sure it is correct */
337 if (name != NULL && issetugid() != 0)
338 if ((name[0] == ':' && name[1] == '/') ||
339 name[0] == '/' || strchr(name, '.'))
340 name = NULL;
341 if (name == NULL && (name = TZDEFAULT) == NULL)
342 return -1;
343 {
344 int doaccess;
345 struct stat stab;
346 /*
347 ** Section 4.9.1 of the C standard says that
348 ** "FILENAME_MAX expands to an integral constant expression
349 ** that is the size needed for an array of char large enough
350 ** to hold the longest file name string that the implementation
351 ** guarantees can be opened."
352 */
353 char fullname[FILENAME_MAX + 1];
354
355 if (name[0] == ':')
356 ++name;
357 doaccess = name[0] == '/';
358 if (!doaccess) {
359 if ((p = TZDIR) == NULL)
360 return -1;
361 if ((strlen(p) + 1 + strlen(name) + 1) >= sizeof fullname)
362 return -1;
363 strcpy(fullname, p);
364 strcat(fullname, "/");
365 strcat(fullname, name);
366 /*
367 ** Set doaccess if '.' (as in "../") shows up in name.
368 */
369 if (strchr(name, '.') != NULL)
370 doaccess = TRUE;
371 name = fullname;
372 }
373 if (doaccess && access(name, R_OK) != 0)
374 return -1;
375 if ((fid = _open(name, O_RDONLY)) == -1)
376 return -1;
377 if ((_fstat(fid, &stab) < 0) || !S_ISREG(stab.st_mode)) {
378 _close(fid);
379 return -1;
380 }
381 }
382 nread = read(fid, u.buf, sizeof u.buf);
383 if (close(fid) < 0 || nread <= 0)
384 return -1;
385 for (stored = 4; stored <= 8; stored *= 2) {
386 int ttisstdcnt;
387 int ttisgmtcnt;
388
389 ttisstdcnt = (int) detzcode(u.tzhead.tzh_ttisstdcnt);
390 ttisgmtcnt = (int) detzcode(u.tzhead.tzh_ttisgmtcnt);
391 sp->leapcnt = (int) detzcode(u.tzhead.tzh_leapcnt);
392 sp->timecnt = (int) detzcode(u.tzhead.tzh_timecnt);
393 sp->typecnt = (int) detzcode(u.tzhead.tzh_typecnt);
394 sp->charcnt = (int) detzcode(u.tzhead.tzh_charcnt);
395 p = u.tzhead.tzh_charcnt + sizeof u.tzhead.tzh_charcnt;
396 if (sp->leapcnt < 0 || sp->leapcnt > TZ_MAX_LEAPS ||
397 sp->typecnt <= 0 || sp->typecnt > TZ_MAX_TYPES ||
398 sp->timecnt < 0 || sp->timecnt > TZ_MAX_TIMES ||
399 sp->charcnt < 0 || sp->charcnt > TZ_MAX_CHARS ||
400 (ttisstdcnt != sp->typecnt && ttisstdcnt != 0) ||
401 (ttisgmtcnt != sp->typecnt && ttisgmtcnt != 0))
402 return -1;
403 if (nread - (p - u.buf) <
404 sp->timecnt * stored + /* ats */
405 sp->timecnt + /* types */
406 sp->typecnt * 6 + /* ttinfos */
407 sp->charcnt + /* chars */
408 sp->leapcnt * (stored + 4) + /* lsinfos */
409 ttisstdcnt + /* ttisstds */
410 ttisgmtcnt) /* ttisgmts */
411 return -1;
412 for (i = 0; i < sp->timecnt; ++i) {
413 sp->ats[i] = (stored == 4) ?
414 detzcode(p) : detzcode64(p);
415 p += stored;
416 }
417 for (i = 0; i < sp->timecnt; ++i) {
418 sp->types[i] = (unsigned char) *p++;
419 if (sp->types[i] >= sp->typecnt)
420 return -1;
421 }
422 for (i = 0; i < sp->typecnt; ++i) {
423 struct ttinfo * ttisp;
424
425 ttisp = &sp->ttis[i];
426 ttisp->tt_gmtoff = detzcode(p);
427 p += 4;
428 ttisp->tt_isdst = (unsigned char) *p++;
429 if (ttisp->tt_isdst != 0 && ttisp->tt_isdst != 1)
430 return -1;
431 ttisp->tt_abbrind = (unsigned char) *p++;
432 if (ttisp->tt_abbrind < 0 ||
433 ttisp->tt_abbrind > sp->charcnt)
434 return -1;
435 }
436 for (i = 0; i < sp->charcnt; ++i)
437 sp->chars[i] = *p++;
438 sp->chars[i] = '\0'; /* ensure '\0' at end */
439 for (i = 0; i < sp->leapcnt; ++i) {
440 struct lsinfo * lsisp;
441
442 lsisp = &sp->lsis[i];
443 lsisp->ls_trans = (stored == 4) ?
444 detzcode(p) : detzcode64(p);
445 p += stored;
446 lsisp->ls_corr = detzcode(p);
447 p += 4;
448 }
449 for (i = 0; i < sp->typecnt; ++i) {
450 struct ttinfo * ttisp;
451
452 ttisp = &sp->ttis[i];
453 if (ttisstdcnt == 0)
454 ttisp->tt_ttisstd = FALSE;
455 else {
456 ttisp->tt_ttisstd = *p++;
457 if (ttisp->tt_ttisstd != TRUE &&
458 ttisp->tt_ttisstd != FALSE)
459 return -1;
460 }
461 }
462 for (i = 0; i < sp->typecnt; ++i) {
463 struct ttinfo * ttisp;
464
465 ttisp = &sp->ttis[i];
466 if (ttisgmtcnt == 0)
467 ttisp->tt_ttisgmt = FALSE;
468 else {
469 ttisp->tt_ttisgmt = *p++;
470 if (ttisp->tt_ttisgmt != TRUE &&
471 ttisp->tt_ttisgmt != FALSE)
472 return -1;
473 }
474 }
475 /*
476 ** Out-of-sort ats should mean we're running on a
477 ** signed time_t system but using a data file with
478 ** unsigned values (or vice versa).
479 */
480 for (i = 0; i < sp->timecnt - 2; ++i)
481 if (sp->ats[i] > sp->ats[i + 1]) {
482 ++i;
483 if (TYPE_SIGNED(time_t)) {
484 /*
485 ** Ignore the end (easy).
486 */
487 sp->timecnt = i;
488 } else {
489 /*
490 ** Ignore the beginning (harder).
491 */
492 int j;
493
494 for (j = 0; j + i < sp->timecnt; ++j) {
495 sp->ats[j] = sp->ats[j + i];
496 sp->types[j] = sp->types[j + i];
497 }
498 sp->timecnt = j;
499 }
500 break;
501 }
502 /*
503 ** If this is an old file, we're done.
504 */
505 if (u.tzhead.tzh_version[0] == '\0')
506 break;
507 nread -= p - u.buf;
508 for (i = 0; i < nread; ++i)
509 u.buf[i] = p[i];
510 /*
511 ** If this is a narrow integer time_t system, we're done.
512 */
513 if (stored >= (int) sizeof(time_t) && TYPE_INTEGRAL(time_t))
514 break;
515 }
516 if (doextend && nread > 2 &&
517 u.buf[0] == '\n' && u.buf[nread - 1] == '\n' &&
518 sp->typecnt + 2 <= TZ_MAX_TYPES) {
519 struct state ts;
520 int result;
521
522 u.buf[nread - 1] = '\0';
523 result = tzparse(&u.buf[1], &ts, FALSE);
524 if (result == 0 && ts.typecnt == 2 &&
525 sp->charcnt + ts.charcnt <= TZ_MAX_CHARS) {
526 for (i = 0; i < 2; ++i)
527 ts.ttis[i].tt_abbrind +=
528 sp->charcnt;
529 for (i = 0; i < ts.charcnt; ++i)
530 sp->chars[sp->charcnt++] =
531 ts.chars[i];
532 i = 0;
533 while (i < ts.timecnt &&
534 ts.ats[i] <=
535 sp->ats[sp->timecnt - 1])
536 ++i;
537 while (i < ts.timecnt &&
538 sp->timecnt < TZ_MAX_TIMES) {
539 sp->ats[sp->timecnt] =
540 ts.ats[i];
541 sp->types[sp->timecnt] =
542 sp->typecnt +
543 ts.types[i];
544 ++sp->timecnt;
545 ++i;
546 }
547 sp->ttis[sp->typecnt++] = ts.ttis[0];
548 sp->ttis[sp->typecnt++] = ts.ttis[1];
549 }
550 }
551 if (sp->timecnt > 1) {
552 for (i = 1; i < sp->timecnt; ++i)
553 if (typesequiv(sp, sp->types[i], sp->types[0]) &&
554 differ_by_repeat(sp->ats[i], sp->ats[0])) {
555 sp->goback = TRUE;
556 break;
557 }
558 for (i = sp->timecnt - 2; i >= 0; --i)
559 if (typesequiv(sp, sp->types[sp->timecnt - 1],
560 sp->types[i]) &&
561 differ_by_repeat(sp->ats[sp->timecnt - 1],
562 sp->ats[i])) {
563 sp->goahead = TRUE;
564 break;
565 }
566 }
567 return 0;
568 }
569
570 static int
571 typesequiv(const struct state * const sp, const int a, const int b)
572 {
573 int result;
574
575 if (sp == NULL ||
576 a < 0 || a >= sp->typecnt ||
577 b < 0 || b >= sp->typecnt)
578 result = FALSE;
579 else {
580 const struct ttinfo * ap = &sp->ttis[a];
581 const struct ttinfo * bp = &sp->ttis[b];
582 result = ap->tt_gmtoff == bp->tt_gmtoff &&
583 ap->tt_isdst == bp->tt_isdst &&
584 ap->tt_ttisstd == bp->tt_ttisstd &&
585 ap->tt_ttisgmt == bp->tt_ttisgmt &&
586 strcmp(&sp->chars[ap->tt_abbrind],
587 &sp->chars[bp->tt_abbrind]) == 0;
588 }
589 return result;
590 }
591
592 static const int mon_lengths[2][MONSPERYEAR] = {
593 { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 },
594 { 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }
595 };
596
597 static const int year_lengths[2] = {
598 DAYSPERNYEAR, DAYSPERLYEAR
599 };
600
601 /*
602 ** Given a pointer into a time zone string, scan until a character that is not
603 ** a valid character in a zone name is found. Return a pointer to that
604 ** character.
605 */
606
607 static const char *
608 getzname(const char *strp)
609 {
610 char c;
611
612 while ((c = *strp) != '\0' && !is_digit(c) && c != ',' && c != '-' &&
613 c != '+')
614 ++strp;
615 return strp;
616 }
617
618 /*
619 ** Given a pointer into an extended time zone string, scan until the ending
620 ** delimiter of the zone name is located. Return a pointer to the delimiter.
621 **
622 ** As with getzname above, the legal character set is actually quite
623 ** restricted, with other characters producing undefined results.
624 ** We don't do any checking here; checking is done later in common-case code.
625 */
626
627 static const char *
628 getqzname(const char *strp, const int delim)
629 {
630 int c;
631
632 while ((c = *strp) != '\0' && c != delim)
633 ++strp;
634 return strp;
635 }
636
637 /*
638 ** Given a pointer into a time zone string, extract a number from that string.
639 ** Check that the number is within a specified range; if it is not, return
640 ** NULL.
641 ** Otherwise, return a pointer to the first character not part of the number.
642 */
643
644 static const char *
645 getnum(const char *strp, int * const nump, const int min, const int max)
646 {
647 char c;
648 int num;
649
650 if (strp == NULL || !is_digit(c = *strp))
651 return NULL;
652 num = 0;
653 do {
654 num = num * 10 + (c - '0');
655 if (num > max)
656 return NULL; /* illegal value */
657 c = *++strp;
658 } while (is_digit(c));
659 if (num < min)
660 return NULL; /* illegal value */
661 *nump = num;
662 return strp;
663 }
664
665 /*
666 ** Given a pointer into a time zone string, extract a number of seconds,
667 ** in hh[:mm[:ss]] form, from the string.
668 ** If any error occurs, return NULL.
669 ** Otherwise, return a pointer to the first character not part of the number
670 ** of seconds.
671 */
672
673 static const char *
674 getsecs(const char *strp, long * const secsp)
675 {
676 int num;
677
678 /*
679 ** `HOURSPERDAY * DAYSPERWEEK - 1' allows quasi-Posix rules like
680 ** "M10.4.6/26", which does not conform to Posix,
681 ** but which specifies the equivalent of
682 ** ``02:00 on the first Sunday on or after 23 Oct''.
683 */
684 strp = getnum(strp, &num, 0, HOURSPERDAY * DAYSPERWEEK - 1);
685 if (strp == NULL)
686 return NULL;
687 *secsp = num * (long) SECSPERHOUR;
688 if (*strp == ':') {
689 ++strp;
690 strp = getnum(strp, &num, 0, MINSPERHOUR - 1);
691 if (strp == NULL)
692 return NULL;
693 *secsp += num * SECSPERMIN;
694 if (*strp == ':') {
695 ++strp;
696 /* `SECSPERMIN' allows for leap seconds. */
697 strp = getnum(strp, &num, 0, SECSPERMIN);
698 if (strp == NULL)
699 return NULL;
700 *secsp += num;
701 }
702 }
703 return strp;
704 }
705
706 /*
707 ** Given a pointer into a time zone string, extract an offset, in
708 ** [+-]hh[:mm[:ss]] form, from the string.
709 ** If any error occurs, return NULL.
710 ** Otherwise, return a pointer to the first character not part of the time.
711 */
712
713 static const char *
714 getoffset(const char *strp, long * const offsetp)
715 {
716 int neg = 0;
717
718 if (*strp == '-') {
719 neg = 1;
720 ++strp;
721 } else if (*strp == '+')
722 ++strp;
723 strp = getsecs(strp, offsetp);
724 if (strp == NULL)
725 return NULL; /* illegal time */
726 if (neg)
727 *offsetp = -*offsetp;
728 return strp;
729 }
730
731 /*
732 ** Given a pointer into a time zone string, extract a rule in the form
733 ** date[/time]. See POSIX section 8 for the format of "date" and "time".
734 ** If a valid rule is not found, return NULL.
735 ** Otherwise, return a pointer to the first character not part of the rule.
736 */
737
738 static const char *
739 getrule(const char *strp, struct rule * const rulep)
740 {
741 if (*strp == 'J') {
742 /*
743 ** Julian day.
744 */
745 rulep->r_type = JULIAN_DAY;
746 ++strp;
747 strp = getnum(strp, &rulep->r_day, 1, DAYSPERNYEAR);
748 } else if (*strp == 'M') {
749 /*
750 ** Month, week, day.
751 */
752 rulep->r_type = MONTH_NTH_DAY_OF_WEEK;
753 ++strp;
754 strp = getnum(strp, &rulep->r_mon, 1, MONSPERYEAR);
755 if (strp == NULL)
756 return NULL;
757 if (*strp++ != '.')
758 return NULL;
759 strp = getnum(strp, &rulep->r_week, 1, 5);
760 if (strp == NULL)
761 return NULL;
762 if (*strp++ != '.')
763 return NULL;
764 strp = getnum(strp, &rulep->r_day, 0, DAYSPERWEEK - 1);
765 } else if (is_digit(*strp)) {
766 /*
767 ** Day of year.
768 */
769 rulep->r_type = DAY_OF_YEAR;
770 strp = getnum(strp, &rulep->r_day, 0, DAYSPERLYEAR - 1);
771 } else return NULL; /* invalid format */
772 if (strp == NULL)
773 return NULL;
774 if (*strp == '/') {
775 /*
776 ** Time specified.
777 */
778 ++strp;
779 strp = getsecs(strp, &rulep->r_time);
780 } else rulep->r_time = 2 * SECSPERHOUR; /* default = 2:00:00 */
781 return strp;
782 }
783
784 /*
785 ** Given the Epoch-relative time of January 1, 00:00:00 UTC, in a year, the
786 ** year, a rule, and the offset from UTC at the time that rule takes effect,
787 ** calculate the Epoch-relative time that rule takes effect.
788 */
789
790 static time_t
791 transtime(const time_t janfirst, const int year,
792 const struct rule * const rulep, const long offset)
793 {
794 int leapyear;
795 time_t value;
796 int i;
797 int d, m1, yy0, yy1, yy2, dow;
798
799 INITIALIZE(value);
800 leapyear = isleap(year);
801 switch (rulep->r_type) {
802
803 case JULIAN_DAY:
804 /*
805 ** Jn - Julian day, 1 == January 1, 60 == March 1 even in leap
806 ** years.
807 ** In non-leap years, or if the day number is 59 or less, just
808 ** add SECSPERDAY times the day number-1 to the time of
809 ** January 1, midnight, to get the day.
810 */
811 value = janfirst + (rulep->r_day - 1) * SECSPERDAY;
812 if (leapyear && rulep->r_day >= 60)
813 value += SECSPERDAY;
814 break;
815
816 case DAY_OF_YEAR:
817 /*
818 ** n - day of year.
819 ** Just add SECSPERDAY times the day number to the time of
820 ** January 1, midnight, to get the day.
821 */
822 value = janfirst + rulep->r_day * SECSPERDAY;
823 break;
824
825 case MONTH_NTH_DAY_OF_WEEK:
826 /*
827 ** Mm.n.d - nth "dth day" of month m.
828 */
829 value = janfirst;
830 for (i = 0; i < rulep->r_mon - 1; ++i)
831 value += mon_lengths[leapyear][i] * SECSPERDAY;
832
833 /*
834 ** Use Zeller's Congruence to get day-of-week of first day of
835 ** month.
836 */
837 m1 = (rulep->r_mon + 9) % 12 + 1;
838 yy0 = (rulep->r_mon <= 2) ? (year - 1) : year;
839 yy1 = yy0 / 100;
840 yy2 = yy0 % 100;
841 dow = ((26 * m1 - 2) / 10 +
842 1 + yy2 + yy2 / 4 + yy1 / 4 - 2 * yy1) % 7;
843 if (dow < 0)
844 dow += DAYSPERWEEK;
845
846 /*
847 ** "dow" is the day-of-week of the first day of the month. Get
848 ** the day-of-month (zero-origin) of the first "dow" day of the
849 ** month.
850 */
851 d = rulep->r_day - dow;
852 if (d < 0)
853 d += DAYSPERWEEK;
854 for (i = 1; i < rulep->r_week; ++i) {
855 if (d + DAYSPERWEEK >=
856 mon_lengths[leapyear][rulep->r_mon - 1])
857 break;
858 d += DAYSPERWEEK;
859 }
860
861 /*
862 ** "d" is the day-of-month (zero-origin) of the day we want.
863 */
864 value += d * SECSPERDAY;
865 break;
866 }
867
868 /*
869 ** "value" is the Epoch-relative time of 00:00:00 UTC on the day in
870 ** question. To get the Epoch-relative time of the specified local
871 ** time on that day, add the transition time and the current offset
872 ** from UTC.
873 */
874 return value + rulep->r_time + offset;
875 }
876
877 /*
878 ** Given a POSIX section 8-style TZ string, fill in the rule tables as
879 ** appropriate.
880 */
881
882 static int
883 tzparse(const char *name, struct state * const sp, const int lastditch)
884 {
885 const char * stdname;
886 const char * dstname;
887 size_t stdlen;
888 size_t dstlen;
889 long stdoffset;
890 long dstoffset;
891 time_t * atp;
892 unsigned char * typep;
893 char * cp;
894 int load_result;
895
896 INITIALIZE(dstname);
897 stdname = name;
898 if (lastditch) {
899 stdlen = strlen(name); /* length of standard zone name */
900 name += stdlen;
901 if (stdlen >= sizeof sp->chars)
902 stdlen = (sizeof sp->chars) - 1;
903 stdoffset = 0;
904 } else {
905 if (*name == '<') {
906 name++;
907 stdname = name;
908 name = getqzname(name, '>');
909 if (*name != '>')
910 return (-1);
911 stdlen = name - stdname;
912 name++;
913 } else {
914 name = getzname(name);
915 stdlen = name - stdname;
916 }
917 if (*name == '\0')
918 return -1;
919 name = getoffset(name, &stdoffset);
920 if (name == NULL)
921 return -1;
922 }
923 load_result = tzload(TZDEFRULES, sp, FALSE);
924 if (load_result != 0)
925 sp->leapcnt = 0; /* so, we're off a little */
926 if (*name != '\0') {
927 if (*name == '<') {
928 dstname = ++name;
929 name = getqzname(name, '>');
930 if (*name != '>')
931 return -1;
932 dstlen = name - dstname;
933 name++;
934 } else {
935 dstname = name;
936 name = getzname(name);
937 dstlen = name - dstname; /* length of DST zone name */
938 }
939 if (*name != '\0' && *name != ',' && *name != ';') {
940 name = getoffset(name, &dstoffset);
941 if (name == NULL)
942 return -1;
943 } else dstoffset = stdoffset - SECSPERHOUR;
944 if (*name == '\0' && load_result != 0)
945 name = TZDEFRULESTRING;
946 if (*name == ',' || *name == ';') {
947 struct rule start;
948 struct rule end;
949 int year;
950 time_t janfirst;
951 time_t starttime;
952 time_t endtime;
953
954 ++name;
955 if ((name = getrule(name, &start)) == NULL)
956 return -1;
957 if (*name++ != ',')
958 return -1;
959 if ((name = getrule(name, &end)) == NULL)
960 return -1;
961 if (*name != '\0')
962 return -1;
963 sp->typecnt = 2; /* standard time and DST */
964 /*
965 ** Two transitions per year, from EPOCH_YEAR forward.
966 */
967 sp->ttis[0].tt_gmtoff = -dstoffset;
968 sp->ttis[0].tt_isdst = 1;
969 sp->ttis[0].tt_abbrind = stdlen + 1;
970 sp->ttis[1].tt_gmtoff = -stdoffset;
971 sp->ttis[1].tt_isdst = 0;
972 sp->ttis[1].tt_abbrind = 0;
973 atp = sp->ats;
974 typep = sp->types;
975 janfirst = 0;
976 sp->timecnt = 0;
977 for (year = EPOCH_YEAR;
978 sp->timecnt + 2 <= TZ_MAX_TIMES;
979 ++year) {
980 time_t newfirst;
981
982 starttime = transtime(janfirst, year, &start,
983 stdoffset);
984 endtime = transtime(janfirst, year, &end,
985 dstoffset);
986 if (starttime > endtime) {
987 *atp++ = endtime;
988 *typep++ = 1; /* DST ends */
989 *atp++ = starttime;
990 *typep++ = 0; /* DST begins */
991 } else {
992 *atp++ = starttime;
993 *typep++ = 0; /* DST begins */
994 *atp++ = endtime;
995 *typep++ = 1; /* DST ends */
996 }
997 sp->timecnt += 2;
998 newfirst = janfirst;
999 newfirst += year_lengths[isleap(year)] *
1000 SECSPERDAY;
1001 if (newfirst <= janfirst)
1002 break;
1003 janfirst = newfirst;
1004 }
1005 } else {
1006 long theirstdoffset;
1007 long theirdstoffset;
1008 long theiroffset;
1009 int isdst;
1010 int i;
1011 int j;
1012
1013 if (*name != '\0')
1014 return -1;
1015 /*
1016 ** Initial values of theirstdoffset and theirdstoffset.
1017 */
1018 theirstdoffset = 0;
1019 for (i = 0; i < sp->timecnt; ++i) {
1020 j = sp->types[i];
1021 if (!sp->ttis[j].tt_isdst) {
1022 theirstdoffset =
1023 -sp->ttis[j].tt_gmtoff;
1024 break;
1025 }
1026 }
1027 theirdstoffset = 0;
1028 for (i = 0; i < sp->timecnt; ++i) {
1029 j = sp->types[i];
1030 if (sp->ttis[j].tt_isdst) {
1031 theirdstoffset =
1032 -sp->ttis[j].tt_gmtoff;
1033 break;
1034 }
1035 }
1036 /*
1037 ** Initially we're assumed to be in standard time.
1038 */
1039 isdst = FALSE;
1040 theiroffset = theirstdoffset;
1041 /*
1042 ** Now juggle transition times and types
1043 ** tracking offsets as you do.
1044 */
1045 for (i = 0; i < sp->timecnt; ++i) {
1046 j = sp->types[i];
1047 sp->types[i] = sp->ttis[j].tt_isdst;
1048 if (sp->ttis[j].tt_ttisgmt) {
1049 /* No adjustment to transition time */
1050 } else {
1051 /*
1052 ** If summer time is in effect, and the
1053 ** transition time was not specified as
1054 ** standard time, add the summer time
1055 ** offset to the transition time;
1056 ** otherwise, add the standard time
1057 ** offset to the transition time.
1058 */
1059 /*
1060 ** Transitions from DST to DDST
1061 ** will effectively disappear since
1062 ** POSIX provides for only one DST
1063 ** offset.
1064 */
1065 if (isdst && !sp->ttis[j].tt_ttisstd) {
1066 sp->ats[i] += dstoffset -
1067 theirdstoffset;
1068 } else {
1069 sp->ats[i] += stdoffset -
1070 theirstdoffset;
1071 }
1072 }
1073 theiroffset = -sp->ttis[j].tt_gmtoff;
1074 if (sp->ttis[j].tt_isdst)
1075 theirdstoffset = theiroffset;
1076 else theirstdoffset = theiroffset;
1077 }
1078 /*
1079 ** Finally, fill in ttis.
1080 ** ttisstd and ttisgmt need not be handled.
1081 */
1082 sp->ttis[0].tt_gmtoff = -stdoffset;
1083 sp->ttis[0].tt_isdst = FALSE;
1084 sp->ttis[0].tt_abbrind = 0;
1085 sp->ttis[1].tt_gmtoff = -dstoffset;
1086 sp->ttis[1].tt_isdst = TRUE;
1087 sp->ttis[1].tt_abbrind = stdlen + 1;
1088 sp->typecnt = 2;
1089 }
1090 } else {
1091 dstlen = 0;
1092 sp->typecnt = 1; /* only standard time */
1093 sp->timecnt = 0;
1094 sp->ttis[0].tt_gmtoff = -stdoffset;
1095 sp->ttis[0].tt_isdst = 0;
1096 sp->ttis[0].tt_abbrind = 0;
1097 }
1098 sp->charcnt = stdlen + 1;
1099 if (dstlen != 0)
1100 sp->charcnt += dstlen + 1;
1101 if ((size_t) sp->charcnt > sizeof sp->chars)
1102 return -1;
1103 cp = sp->chars;
1104 strncpy(cp, stdname, stdlen);
1105 cp += stdlen;
1106 *cp++ = '\0';
1107 if (dstlen != 0) {
1108 strncpy(cp, dstname, dstlen);
1109 *(cp + dstlen) = '\0';
1110 }
1111 return 0;
1112 }
1113
1114 static void
1115 gmtload(struct state * const sp)
1116 {
1117 if (tzload(gmt, sp, TRUE) != 0)
1118 tzparse(gmt, sp, TRUE);
1119 }
1120
1121 static void
1122 tzsetwall_basic(int rdlocked)
1123 {
1124 if (!rdlocked)
1125 _RWLOCK_RDLOCK(&lcl_rwlock);
1126 if (lcl_is_set < 0) {
1127 if (!rdlocked)
1128 _RWLOCK_UNLOCK(&lcl_rwlock);
1129 return;
1130 }
1131 _RWLOCK_UNLOCK(&lcl_rwlock);
1132
1133 _RWLOCK_WRLOCK(&lcl_rwlock);
1134 lcl_is_set = -1;
1135
1136 if (tzload(NULL, lclptr, TRUE) != 0)
1137 gmtload(lclptr);
1138 settzname();
1139 _RWLOCK_UNLOCK(&lcl_rwlock);
1140
1141 if (rdlocked)
1142 _RWLOCK_RDLOCK(&lcl_rwlock);
1143 }
1144
1145 void
1146 tzsetwall(void)
1147 {
1148 tzsetwall_basic(0);
1149 }
1150
1151 static void
1152 tzset_basic(int rdlocked)
1153 {
1154 const char * name;
1155
1156 name = getenv("TZ");
1157 if (name == NULL) {
1158 tzsetwall_basic(rdlocked);
1159 return;
1160 }
1161
1162 if (!rdlocked)
1163 _RWLOCK_RDLOCK(&lcl_rwlock);
1164 if (lcl_is_set > 0 && strcmp(lcl_TZname, name) == 0) {
1165 if (!rdlocked)
1166 _RWLOCK_UNLOCK(&lcl_rwlock);
1167 return;
1168 }
1169 _RWLOCK_UNLOCK(&lcl_rwlock);
1170
1171 _RWLOCK_WRLOCK(&lcl_rwlock);
1172 lcl_is_set = strlen(name) < sizeof lcl_TZname;
1173 if (lcl_is_set)
1174 strcpy(lcl_TZname, name);
1175
1176 if (*name == '\0') {
1177 /*
1178 ** User wants it fast rather than right.
1179 */
1180 lclptr->leapcnt = 0; /* so, we're off a little */
1181 lclptr->timecnt = 0;
1182 lclptr->typecnt = 0;
1183 lclptr->ttis[0].tt_isdst = 0;
1184 lclptr->ttis[0].tt_gmtoff = 0;
1185 lclptr->ttis[0].tt_abbrind = 0;
1186 strcpy(lclptr->chars, gmt);
1187 } else if (tzload(name, lclptr, TRUE) != 0)
1188 if (name[0] == ':' || tzparse(name, lclptr, FALSE) != 0)
1189 gmtload(lclptr);
1190 settzname();
1191 _RWLOCK_UNLOCK(&lcl_rwlock);
1192
1193 if (rdlocked)
1194 _RWLOCK_RDLOCK(&lcl_rwlock);
1195 }
1196
1197 void
1198 tzset(void)
1199 {
1200 tzset_basic(0);
1201 }
1202
1203 /*
1204 ** The easy way to behave "as if no library function calls" localtime
1205 ** is to not call it--so we drop its guts into "localsub", which can be
1206 ** freely called. (And no, the PANS doesn't require the above behavior--
1207 ** but it *is* desirable.)
1208 **
1209 ** The unused offset argument is for the benefit of mktime variants.
1210 */
1211
1212 /*ARGSUSED*/
1213 static struct tm *
1214 localsub(const time_t * const timep, const long offset __unused,
1215 struct tm * const tmp)
1216 {
1217 struct state * sp;
1218 const struct ttinfo * ttisp;
1219 int i;
1220 struct tm * result;
1221 const time_t t = *timep;
1222
1223 sp = lclptr;
1224
1225 if ((sp->goback && t < sp->ats[0]) ||
1226 (sp->goahead && t > sp->ats[sp->timecnt - 1])) {
1227 time_t newt = t;
1228 time_t seconds;
1229 time_t tcycles;
1230 int_fast64_t icycles;
1231
1232 if (t < sp->ats[0])
1233 seconds = sp->ats[0] - t;
1234 else seconds = t - sp->ats[sp->timecnt - 1];
1235 --seconds;
1236 tcycles = seconds / YEARSPERREPEAT / AVGSECSPERYEAR;
1237 ++tcycles;
1238 icycles = tcycles;
1239 if (tcycles - icycles >= 1 || icycles - tcycles >= 1)
1240 return NULL;
1241 seconds = icycles;
1242 seconds *= YEARSPERREPEAT;
1243 seconds *= AVGSECSPERYEAR;
1244 if (t < sp->ats[0])
1245 newt += seconds;
1246 else newt -= seconds;
1247 if (newt < sp->ats[0] ||
1248 newt > sp->ats[sp->timecnt - 1])
1249 return NULL; /* "cannot happen" */
1250 result = localsub(&newt, offset, tmp);
1251 if (result == tmp) {
1252 time_t newy;
1253
1254 newy = tmp->tm_year;
1255 if (t < sp->ats[0])
1256 newy -= icycles * YEARSPERREPEAT;
1257 else newy += icycles * YEARSPERREPEAT;
1258 tmp->tm_year = newy;
1259 if (tmp->tm_year != newy)
1260 return NULL;
1261 }
1262 return result;
1263 }
1264 if (sp->timecnt == 0 || t < sp->ats[0]) {
1265 i = 0;
1266 while (sp->ttis[i].tt_isdst)
1267 if (++i >= sp->typecnt) {
1268 i = 0;
1269 break;
1270 }
1271 } else {
1272 int lo = 1;
1273 int hi = sp->timecnt;
1274
1275 while (lo < hi) {
1276 int mid = (lo + hi) >> 1;
1277
1278 if (t < sp->ats[mid])
1279 hi = mid;
1280 else lo = mid + 1;
1281 }
1282 i = (int) sp->types[lo - 1];
1283 }
1284 ttisp = &sp->ttis[i];
1285 /*
1286 ** To get (wrong) behavior that's compatible with System V Release 2.0
1287 ** you'd replace the statement below with
1288 ** t += ttisp->tt_gmtoff;
1289 ** timesub(&t, 0L, sp, tmp);
1290 */
1291 result = timesub(&t, ttisp->tt_gmtoff, sp, tmp);
1292 tmp->tm_isdst = ttisp->tt_isdst;
1293 tzname[tmp->tm_isdst] = &sp->chars[ttisp->tt_abbrind];
1294 #ifdef TM_ZONE
1295 tmp->TM_ZONE = &sp->chars[ttisp->tt_abbrind];
1296 #endif /* defined TM_ZONE */
1297 return result;
1298 }
1299
1300 struct tm *
1301 localtime_r(const time_t * const timep, struct tm *p_tm)
1302 {
1303 _RWLOCK_RDLOCK(&lcl_rwlock);
1304 tzset_basic(1);
1305 localsub(timep, 0L, p_tm);
1306 _RWLOCK_UNLOCK(&lcl_rwlock);
1307 return(p_tm);
1308 }
1309
1310 struct tm *
1311 localtime(const time_t * const timep)
1312 {
1313 static pthread_mutex_t localtime_mutex = PTHREAD_MUTEX_INITIALIZER;
1314 static pthread_key_t localtime_key = -1;
1315 struct tm *p_tm;
1316
1317 if (__isthreaded != 0) {
1318 if (localtime_key < 0) {
1319 _pthread_mutex_lock(&localtime_mutex);
1320 if (localtime_key < 0) {
1321 if (_pthread_key_create(&localtime_key, free) < 0) {
1322 _pthread_mutex_unlock(&localtime_mutex);
1323 return(NULL);
1324 }
1325 }
1326 _pthread_mutex_unlock(&localtime_mutex);
1327 }
1328 p_tm = _pthread_getspecific(localtime_key);
1329 if (p_tm == NULL) {
1330 if ((p_tm = (struct tm *)malloc(sizeof(struct tm)))
1331 == NULL)
1332 return(NULL);
1333 _pthread_setspecific(localtime_key, p_tm);
1334 }
1335 _RWLOCK_RDLOCK(&lcl_rwlock);
1336 tzset_basic(1);
1337 localsub(timep, 0L, p_tm);
1338 _RWLOCK_UNLOCK(&lcl_rwlock);
1339 return(p_tm);
1340 } else {
1341 tzset_basic(0);
1342 localsub(timep, 0L, &tm);
1343 return(&tm);
1344 }
1345 }
1346
1347 /*
1348 ** gmtsub is to gmtime as localsub is to localtime.
1349 */
1350
1351 static struct tm *
1352 gmtsub(const time_t * const timep, const long offset, struct tm * const tmp)
1353 {
1354 struct tm * result;
1355
1356 if (!gmt_is_set) {
1357 _MUTEX_LOCK(&gmt_mutex);
1358 if (!gmt_is_set) {
1359 gmtload(gmtptr);
1360 gmt_is_set = TRUE;
1361 }
1362 _MUTEX_UNLOCK(&gmt_mutex);
1363 }
1364 result = timesub(timep, offset, gmtptr, tmp);
1365 #ifdef TM_ZONE
1366 /*
1367 ** Could get fancy here and deliver something such as
1368 ** "UTC+xxxx" or "UTC-xxxx" if offset is non-zero,
1369 ** but this is no time for a treasure hunt.
1370 */
1371 if (offset != 0)
1372 tmp->TM_ZONE = wildabbr;
1373 else
1374 tmp->TM_ZONE = gmtptr->chars;
1375 #endif /* defined TM_ZONE */
1376 return result;
1377 }
1378
1379 struct tm *
1380 gmtime(const time_t * const timep)
1381 {
1382 static pthread_mutex_t gmtime_mutex = PTHREAD_MUTEX_INITIALIZER;
1383 static pthread_key_t gmtime_key = -1;
1384 struct tm *p_tm;
1385
1386 if (__isthreaded != 0) {
1387 if (gmtime_key < 0) {
1388 _pthread_mutex_lock(&gmtime_mutex);
1389 if (gmtime_key < 0) {
1390 if (_pthread_key_create(&gmtime_key, free) < 0) {
1391 _pthread_mutex_unlock(&gmtime_mutex);
1392 return(NULL);
1393 }
1394 }
1395 _pthread_mutex_unlock(&gmtime_mutex);
1396 }
1397 /*
1398 * Changed to follow POSIX.1 threads standard, which
1399 * is what BSD currently has.
1400 */
1401 if ((p_tm = _pthread_getspecific(gmtime_key)) == NULL) {
1402 if ((p_tm = (struct tm *)malloc(sizeof(struct tm)))
1403 == NULL) {
1404 return(NULL);
1405 }
1406 _pthread_setspecific(gmtime_key, p_tm);
1407 }
1408 return gmtsub(timep, 0L, p_tm);
1409 } else {
1410 return gmtsub(timep, 0L, &tm);
1411 }
1412 }
1413
1414 struct tm *
1415 gmtime_r(const time_t * timep, struct tm * tmp)
1416 {
1417 return gmtsub(timep, 0L, tmp);
1418 }
1419
1420 struct tm *
1421 offtime(const time_t * const timep, const long offset)
1422 {
1423 return gmtsub(timep, offset, &tm);
1424 }
1425
1426 /*
1427 ** Return the number of leap years through the end of the given year
1428 ** where, to make the math easy, the answer for year zero is defined as zero.
1429 */
1430
1431 static int
1432 leaps_thru_end_of(const int y)
1433 {
1434 return (y >= 0) ? (y / 4 - y / 100 + y / 400) :
1435 -(leaps_thru_end_of(-(y + 1)) + 1);
1436 }
1437
1438 static struct tm *
1439 timesub(const time_t * const timep, const long offset,
1440 const struct state * const sp, struct tm * const tmp)
1441 {
1442 const struct lsinfo * lp;
1443 time_t tdays;
1444 int idays; /* unsigned would be so 2003 */
1445 long rem;
1446 int y;
1447 int yleap;
1448 const int * ip;
1449 long corr;
1450 int hit;
1451 int i;
1452
1453 corr = 0;
1454 hit = 0;
1455 i = sp->leapcnt;
1456
1457 while (--i >= 0) {
1458 lp = &sp->lsis[i];
1459 if (*timep >= lp->ls_trans) {
1460 if (*timep == lp->ls_trans) {
1461 hit = ((i == 0 && lp->ls_corr > 0) ||
1462 lp->ls_corr > sp->lsis[i - 1].ls_corr);
1463 if (hit)
1464 while (i > 0 &&
1465 sp->lsis[i].ls_trans ==
1466 sp->lsis[i - 1].ls_trans + 1 &&
1467 sp->lsis[i].ls_corr ==
1468 sp->lsis[i - 1].ls_corr + 1) {
1469 ++hit;
1470 --i;
1471 }
1472 }
1473 corr = lp->ls_corr;
1474 break;
1475 }
1476 }
1477 y = EPOCH_YEAR;
1478 tdays = *timep / SECSPERDAY;
1479 rem = *timep - tdays * SECSPERDAY;
1480 while (tdays < 0 || tdays >= year_lengths[isleap(y)]) {
1481 int newy;
1482 time_t tdelta;
1483 int idelta;
1484 int leapdays;
1485
1486 tdelta = tdays / DAYSPERLYEAR;
1487 idelta = tdelta;
1488 if (tdelta - idelta >= 1 || idelta - tdelta >= 1)
1489 return NULL;
1490 if (idelta == 0)
1491 idelta = (tdays < 0) ? -1 : 1;
1492 newy = y;
1493 if (increment_overflow(&newy, idelta))
1494 return NULL;
1495 leapdays = leaps_thru_end_of(newy - 1) -
1496 leaps_thru_end_of(y - 1);
1497 tdays -= ((time_t) newy - y) * DAYSPERNYEAR;
1498 tdays -= leapdays;
1499 y = newy;
1500 }
1501 {
1502 long seconds;
1503
1504 seconds = tdays * SECSPERDAY + 0.5;
1505 tdays = seconds / SECSPERDAY;
1506 rem += seconds - tdays * SECSPERDAY;
1507 }
1508 /*
1509 ** Given the range, we can now fearlessly cast...
1510 */
1511 idays = tdays;
1512 rem += offset - corr;
1513 while (rem < 0) {
1514 rem += SECSPERDAY;
1515 --idays;
1516 }
1517 while (rem >= SECSPERDAY) {
1518 rem -= SECSPERDAY;
1519 ++idays;
1520 }
1521 while (idays < 0) {
1522 if (increment_overflow(&y, -1))
1523 return NULL;
1524 idays += year_lengths[isleap(y)];
1525 }
1526 while (idays >= year_lengths[isleap(y)]) {
1527 idays -= year_lengths[isleap(y)];
1528 if (increment_overflow(&y, 1))
1529 return NULL;
1530 }
1531 tmp->tm_year = y;
1532 if (increment_overflow(&tmp->tm_year, -TM_YEAR_BASE))
1533 return NULL;
1534 tmp->tm_yday = idays;
1535 /*
1536 ** The "extra" mods below avoid overflow problems.
1537 */
1538 tmp->tm_wday = EPOCH_WDAY +
1539 ((y - EPOCH_YEAR) % DAYSPERWEEK) *
1540 (DAYSPERNYEAR % DAYSPERWEEK) +
1541 leaps_thru_end_of(y - 1) -
1542 leaps_thru_end_of(EPOCH_YEAR - 1) +
1543 idays;
1544 tmp->tm_wday %= DAYSPERWEEK;
1545 if (tmp->tm_wday < 0)
1546 tmp->tm_wday += DAYSPERWEEK;
1547 tmp->tm_hour = (int) (rem / SECSPERHOUR);
1548 rem %= SECSPERHOUR;
1549 tmp->tm_min = (int) (rem / SECSPERMIN);
1550 /*
1551 ** A positive leap second requires a special
1552 ** representation. This uses "... ??:59:60" et seq.
1553 */
1554 tmp->tm_sec = (int) (rem % SECSPERMIN) + hit;
1555 ip = mon_lengths[isleap(y)];
1556 for (tmp->tm_mon = 0; idays >= ip[tmp->tm_mon]; ++(tmp->tm_mon))
1557 idays -= ip[tmp->tm_mon];
1558 tmp->tm_mday = (int) (idays + 1);
1559 tmp->tm_isdst = 0;
1560 #ifdef TM_GMTOFF
1561 tmp->TM_GMTOFF = offset;
1562 #endif /* defined TM_GMTOFF */
1563 return tmp;
1564 }
1565
1566 char *
1567 ctime(const time_t * const timep)
1568 {
1569 /*
1570 ** Section 4.12.3.2 of X3.159-1989 requires that
1571 ** The ctime function converts the calendar time pointed to by timer
1572 ** to local time in the form of a string. It is equivalent to
1573 ** asctime(localtime(timer))
1574 */
1575 return asctime(localtime(timep));
1576 }
1577
1578 char *
1579 ctime_r(const time_t * const timep, char *buf)
1580 {
1581 struct tm mytm;
1582 return asctime_r(localtime_r(timep, &mytm), buf);
1583 }
1584
1585 /*
1586 ** Adapted from code provided by Robert Elz, who writes:
1587 ** The "best" way to do mktime I think is based on an idea of Bob
1588 ** Kridle's (so its said...) from a long time ago.
1589 ** It does a binary search of the time_t space. Since time_t's are
1590 ** just 32 bits, its a max of 32 iterations (even at 64 bits it
1591 ** would still be very reasonable).
1592 */
1593
1594 #ifndef WRONG
1595 #define WRONG (-1)
1596 #endif /* !defined WRONG */
1597
1598 /*
1599 ** Simplified normalize logic courtesy Paul Eggert.
1600 */
1601
1602 static int
1603 increment_overflow(int *number, int delta)
1604 {
1605 int number0;
1606
1607 number0 = *number;
1608 *number += delta;
1609 return (*number < number0) != (delta < 0);
1610 }
1611
1612 static int
1613 long_increment_overflow(long *number, int delta)
1614 {
1615 long number0;
1616
1617 number0 = *number;
1618 *number += delta;
1619 return (*number < number0) != (delta < 0);
1620 }
1621
1622 static int
1623 normalize_overflow(int * const tensptr, int * const unitsptr, const int base)
1624 {
1625 int tensdelta;
1626
1627 tensdelta = (*unitsptr >= 0) ?
1628 (*unitsptr / base) :
1629 (-1 - (-1 - *unitsptr) / base);
1630 *unitsptr -= tensdelta * base;
1631 return increment_overflow(tensptr, tensdelta);
1632 }
1633
1634 static int
1635 long_normalize_overflow(long * const tensptr, int * const unitsptr,
1636 const int base)
1637 {
1638 int tensdelta;
1639
1640 tensdelta = (*unitsptr >= 0) ?
1641 (*unitsptr / base) :
1642 (-1 - (-1 - *unitsptr) / base);
1643 *unitsptr -= tensdelta * base;
1644 return long_increment_overflow(tensptr, tensdelta);
1645 }
1646
1647 static int
1648 tmcomp(const struct tm * const atmp, const struct tm * const btmp)
1649 {
1650 int result;
1651
1652 if ((result = (atmp->tm_year - btmp->tm_year)) == 0 &&
1653 (result = (atmp->tm_mon - btmp->tm_mon)) == 0 &&
1654 (result = (atmp->tm_mday - btmp->tm_mday)) == 0 &&
1655 (result = (atmp->tm_hour - btmp->tm_hour)) == 0 &&
1656 (result = (atmp->tm_min - btmp->tm_min)) == 0)
1657 result = atmp->tm_sec - btmp->tm_sec;
1658 return result;
1659 }
1660
1661 static time_t
1662 time2sub(struct tm * const tmp,
1663 struct tm * (* const funcp)(const time_t *, long, struct tm *),
1664 const long offset, int * const okayp, const int do_norm_secs)
1665 {
1666 const struct state * sp;
1667 int dir;
1668 int i, j;
1669 int saved_seconds;
1670 long li;
1671 time_t lo;
1672 time_t hi;
1673 long y;
1674 time_t newt;
1675 time_t t;
1676 struct tm yourtm, mytm;
1677
1678 *okayp = FALSE;
1679 yourtm = *tmp;
1680 if (do_norm_secs) {
1681 if (normalize_overflow(&yourtm.tm_min, &yourtm.tm_sec,
1682 SECSPERMIN))
1683 return WRONG;
1684 }
1685 if (normalize_overflow(&yourtm.tm_hour, &yourtm.tm_min, MINSPERHOUR))
1686 return WRONG;
1687 if (normalize_overflow(&yourtm.tm_mday, &yourtm.tm_hour, HOURSPERDAY))
1688 return WRONG;
1689 y = yourtm.tm_year;
1690 if (long_normalize_overflow(&y, &yourtm.tm_mon, MONSPERYEAR))
1691 return WRONG;
1692 /*
1693 ** Turn y into an actual year number for now.
1694 ** It is converted back to an offset from TM_YEAR_BASE later.
1695 */
1696 if (long_increment_overflow(&y, TM_YEAR_BASE))
1697 return WRONG;
1698 while (yourtm.tm_mday <= 0) {
1699 if (long_increment_overflow(&y, -1))
1700 return WRONG;
1701 li = y + (1 < yourtm.tm_mon);
1702 yourtm.tm_mday += year_lengths[isleap(li)];
1703 }
1704 while (yourtm.tm_mday > DAYSPERLYEAR) {
1705 li = y + (1 < yourtm.tm_mon);
1706 yourtm.tm_mday -= year_lengths[isleap(li)];
1707 if (long_increment_overflow(&y, 1))
1708 return WRONG;
1709 }
1710 for ( ; ; ) {
1711 i = mon_lengths[isleap(y)][yourtm.tm_mon];
1712 if (yourtm.tm_mday <= i)
1713 break;
1714 yourtm.tm_mday -= i;
1715 if (++yourtm.tm_mon >= MONSPERYEAR) {
1716 yourtm.tm_mon = 0;
1717 if (long_increment_overflow(&y, 1))
1718 return WRONG;
1719 }
1720 }
1721 if (long_increment_overflow(&y, -TM_YEAR_BASE))
1722 return WRONG;
1723 yourtm.tm_year = y;
1724 if (yourtm.tm_year != y)
1725 return WRONG;
1726 if (yourtm.tm_sec >= 0 && yourtm.tm_sec < SECSPERMIN)
1727 saved_seconds = 0;
1728 else if (y + TM_YEAR_BASE < EPOCH_YEAR) {
1729 /*
1730 ** We can't set tm_sec to 0, because that might push the
1731 ** time below the minimum representable time.
1732 ** Set tm_sec to 59 instead.
1733 ** This assumes that the minimum representable time is
1734 ** not in the same minute that a leap second was deleted from,
1735 ** which is a safer assumption than using 58 would be.
1736 */
1737 if (increment_overflow(&yourtm.tm_sec, 1 - SECSPERMIN))
1738 return WRONG;
1739 saved_seconds = yourtm.tm_sec;
1740 yourtm.tm_sec = SECSPERMIN - 1;
1741 } else {
1742 saved_seconds = yourtm.tm_sec;
1743 yourtm.tm_sec = 0;
1744 }
1745 /*
1746 ** Do a binary search (this works whatever time_t's type is).
1747 */
1748 if (!TYPE_SIGNED(time_t)) {
1749 lo = 0;
1750 hi = lo - 1;
1751 } else if (!TYPE_INTEGRAL(time_t)) {
1752 if (sizeof(time_t) > sizeof(float))
1753 hi = (time_t) DBL_MAX;
1754 else hi = (time_t) FLT_MAX;
1755 lo = -hi;
1756 } else {
1757 lo = 1;
1758 for (i = 0; i < (int) TYPE_BIT(time_t) - 1; ++i)
1759 lo *= 2;
1760 hi = -(lo + 1);
1761 }
1762 for ( ; ; ) {
1763 t = lo / 2 + hi / 2;
1764 if (t < lo)
1765 t = lo;
1766 else if (t > hi)
1767 t = hi;
1768 if ((*funcp)(&t, offset, &mytm) == NULL) {
1769 /*
1770 ** Assume that t is too extreme to be represented in
1771 ** a struct tm; arrange things so that it is less
1772 ** extreme on the next pass.
1773 */
1774 dir = (t > 0) ? 1 : -1;
1775 } else dir = tmcomp(&mytm, &yourtm);
1776 if (dir != 0) {
1777 if (t == lo) {
1778 ++t;
1779 if (t <= lo)
1780 return WRONG;
1781 ++lo;
1782 } else if (t == hi) {
1783 --t;
1784 if (t >= hi)
1785 return WRONG;
1786 --hi;
1787 }
1788 if (lo > hi)
1789 return WRONG;
1790 if (dir > 0)
1791 hi = t;
1792 else lo = t;
1793 continue;
1794 }
1795 if (yourtm.tm_isdst < 0 || mytm.tm_isdst == yourtm.tm_isdst)
1796 break;
1797 /*
1798 ** Right time, wrong type.
1799 ** Hunt for right time, right type.
1800 ** It's okay to guess wrong since the guess
1801 ** gets checked.
1802 */
1803 sp = (const struct state *)
1804 ((funcp == localsub) ? lclptr : gmtptr);
1805
1806 for (i = sp->typecnt - 1; i >= 0; --i) {
1807 if (sp->ttis[i].tt_isdst != yourtm.tm_isdst)
1808 continue;
1809 for (j = sp->typecnt - 1; j >= 0; --j) {
1810 if (sp->ttis[j].tt_isdst == yourtm.tm_isdst)
1811 continue;
1812 newt = t + sp->ttis[j].tt_gmtoff -
1813 sp->ttis[i].tt_gmtoff;
1814 if ((*funcp)(&newt, offset, &mytm) == NULL)
1815 continue;
1816 if (tmcomp(&mytm, &yourtm) != 0)
1817 continue;
1818 if (mytm.tm_isdst != yourtm.tm_isdst)
1819 continue;
1820 /*
1821 ** We have a match.
1822 */
1823 t = newt;
1824 goto label;
1825 }
1826 }
1827 return WRONG;
1828 }
1829 label:
1830 newt = t + saved_seconds;
1831 if ((newt < t) != (saved_seconds < 0))
1832 return WRONG;
1833 t = newt;
1834 if ((*funcp)(&t, offset, tmp))
1835 *okayp = TRUE;
1836 return t;
1837 }
1838
1839 static time_t
1840 time2(struct tm * const tmp,
1841 struct tm * (* const funcp)(const time_t *, long, struct tm *),
1842 const long offset, int * const okayp)
1843 {
1844 time_t t;
1845
1846 /*
1847 ** First try without normalization of seconds
1848 ** (in case tm_sec contains a value associated with a leap second).
1849 ** If that fails, try with normalization of seconds.
1850 */
1851 t = time2sub(tmp, funcp, offset, okayp, FALSE);
1852 return *okayp ? t : time2sub(tmp, funcp, offset, okayp, TRUE);
1853 }
1854
1855 static time_t
1856 time1(struct tm * const tmp,
1857 struct tm * (* const funcp)(const time_t *, long, struct tm *),
1858 const long offset)
1859 {
1860 time_t t;
1861 const struct state * sp;
1862 int samei, otheri;
1863 int sameind, otherind;
1864 int i;
1865 int nseen;
1866 int seen[TZ_MAX_TYPES];
1867 int types[TZ_MAX_TYPES];
1868 int okay;
1869
1870 if (tmp == NULL) {
1871 errno = EINVAL;
1872 return WRONG;
1873 }
1874 if (tmp->tm_isdst > 1)
1875 tmp->tm_isdst = 1;
1876 t = time2(tmp, funcp, offset, &okay);
1877
1878 /*
1879 ** PCTS code courtesy Grant Sullivan.
1880 */
1881 if (okay)
1882 return t;
1883 if (tmp->tm_isdst < 0)
1884 tmp->tm_isdst = 0; /* reset to std and try again */
1885
1886 /*
1887 ** We're supposed to assume that somebody took a time of one type
1888 ** and did some math on it that yielded a "struct tm" that's bad.
1889 ** We try to divine the type they started from and adjust to the
1890 ** type they need.
1891 */
1892 sp = (const struct state *) ((funcp == localsub) ? lclptr : gmtptr);
1893
1894 for (i = 0; i < sp->typecnt; ++i)
1895 seen[i] = FALSE;
1896 nseen = 0;
1897 for (i = sp->timecnt - 1; i >= 0; --i)
1898 if (!seen[sp->types[i]]) {
1899 seen[sp->types[i]] = TRUE;
1900 types[nseen++] = sp->types[i];
1901 }
1902 for (sameind = 0; sameind < nseen; ++sameind) {
1903 samei = types[sameind];
1904 if (sp->ttis[samei].tt_isdst != tmp->tm_isdst)
1905 continue;
1906 for (otherind = 0; otherind < nseen; ++otherind) {
1907 otheri = types[otherind];
1908 if (sp->ttis[otheri].tt_isdst == tmp->tm_isdst)
1909 continue;
1910 tmp->tm_sec += sp->ttis[otheri].tt_gmtoff -
1911 sp->ttis[samei].tt_gmtoff;
1912 tmp->tm_isdst = !tmp->tm_isdst;
1913 t = time2(tmp, funcp, offset, &okay);
1914 if (okay)
1915 return t;
1916 tmp->tm_sec -= sp->ttis[otheri].tt_gmtoff -
1917 sp->ttis[samei].tt_gmtoff;
1918 tmp->tm_isdst = !tmp->tm_isdst;
1919 }
1920 }
1921 return WRONG;
1922 }
1923
1924 time_t
1925 mktime(struct tm * const tmp)
1926 {
1927 time_t mktime_return_value;
1928 _RWLOCK_RDLOCK(&lcl_rwlock);
1929 tzset_basic(1);
1930 mktime_return_value = time1(tmp, localsub, 0L);
1931 _RWLOCK_UNLOCK(&lcl_rwlock);
1932 return(mktime_return_value);
1933 }
1934
1935 time_t
1936 timelocal(struct tm * const tmp)
1937 {
1938 if (tmp != NULL)
1939 tmp->tm_isdst = -1; /* in case it wasn't initialized */
1940 return mktime(tmp);
1941 }
1942
1943 time_t
1944 timegm(struct tm * const tmp)
1945 {
1946 if (tmp != NULL)
1947 tmp->tm_isdst = 0;
1948 return time1(tmp, gmtsub, 0L);
1949 }
1950
1951 time_t
1952 timeoff(struct tm * const tmp, const long offset)
1953 {
1954 if (tmp != NULL)
1955 tmp->tm_isdst = 0;
1956 return time1(tmp, gmtsub, offset);
1957 }
1958
1959 #ifdef CMUCS
1960
1961 /*
1962 ** The following is supplied for compatibility with
1963 ** previous versions of the CMUCS runtime library.
1964 */
1965
1966 long
1967 gtime(struct tm * const tmp)
1968 {
1969 const time_t t = mktime(tmp);
1970
1971 if (t == WRONG)
1972 return -1;
1973 return t;
1974 }
1975
1976 #endif /* defined CMUCS */
1977
1978 /*
1979 ** XXX--is the below the right way to conditionalize??
1980 */
1981
1982 /*
1983 ** IEEE Std 1003.1-1988 (POSIX) legislates that 536457599
1984 ** shall correspond to "Wed Dec 31 23:59:59 UTC 1986", which
1985 ** is not the case if we are accounting for leap seconds.
1986 ** So, we provide the following conversion routines for use
1987 ** when exchanging timestamps with POSIX conforming systems.
1988 */
1989
1990 static long
1991 leapcorr(time_t *timep)
1992 {
1993 struct state * sp;
1994 struct lsinfo * lp;
1995 int i;
1996
1997 sp = lclptr;
1998 i = sp->leapcnt;
1999 while (--i >= 0) {
2000 lp = &sp->lsis[i];
2001 if (*timep >= lp->ls_trans)
2002 return lp->ls_corr;
2003 }
2004 return 0;
2005 }
2006
2007 time_t
2008 time2posix(time_t t)
2009 {
2010 tzset();
2011 return t - leapcorr(&t);
2012 }
2013
2014 time_t
2015 posix2time(time_t t)
2016 {
2017 time_t x;
2018 time_t y;
2019
2020 tzset();
2021 /*
2022 ** For a positive leap second hit, the result
2023 ** is not unique. For a negative leap second
2024 ** hit, the corresponding time doesn't exist,
2025 ** so we return an adjacent second.
2026 */
2027 x = t + leapcorr(&t);
2028 y = x - leapcorr(&x);
2029 if (y < t) {
2030 do {
2031 x++;
2032 y = x - leapcorr(&x);
2033 } while (y < t);
2034 if (t != y)
2035 return x - 1;
2036 } else if (y > t) {
2037 do {
2038 --x;
2039 y = x - leapcorr(&x);
2040 } while (y > t);
2041 if (t != y)
2042 return x + 1;
2043 }
2044 return x;
2045 }
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