1 /* $OpenBSD: localtime.c,v 1.66 2024/04/04 02:20:01 millert Exp $ */
2 /*
3 ** This file is in the public domain, so clarified as of
4 ** 1996-06-05 by Arthur David Olson.
5 */
6
7 /*
8 ** Leap second handling from Bradley White.
9 ** POSIX-style TZ environment variable handling from Guy Harris.
10 */
11
12 #include <ctype.h>
13 #include <errno.h>
14 #include <fcntl.h>
15 #include <stdint.h>
16 #include <stdlib.h>
17 #include <string.h>
18 #include <unistd.h>
19
20 #include "private.h"
21 #include "tzfile.h"
22 #include "thread_private.h"
23
24 #ifndef TZ_ABBR_MAX_LEN
25 #define TZ_ABBR_MAX_LEN 16
26 #endif /* !defined TZ_ABBR_MAX_LEN */
27
28 #ifndef TZ_ABBR_CHAR_SET
29 #define TZ_ABBR_CHAR_SET \
30 "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789 :+-._"
31 #endif /* !defined TZ_ABBR_CHAR_SET */
32
33 #ifndef TZ_ABBR_ERR_CHAR
34 #define TZ_ABBR_ERR_CHAR '_'
35 #endif /* !defined TZ_ABBR_ERR_CHAR */
36
37 #ifndef WILDABBR
38 /*
39 ** Someone might make incorrect use of a time zone abbreviation:
40 ** 1. They might reference tzname[0] before calling tzset (explicitly
41 ** or implicitly).
42 ** 2. They might reference tzname[1] before calling tzset (explicitly
43 ** or implicitly).
44 ** 3. They might reference tzname[1] after setting to a time zone
45 ** in which Daylight Saving Time is never observed.
46 ** 4. They might reference tzname[0] after setting to a time zone
47 ** in which Standard Time is never observed.
48 ** 5. They might reference tm.tm_zone after calling offtime.
49 ** What's best to do in the above cases is open to debate;
50 ** for now, we just set things up so that in any of the five cases
51 ** WILDABBR is used. Another possibility: initialize tzname[0] to the
52 ** string "tzname[0] used before set", and similarly for the other cases.
53 ** And another: initialize tzname[0] to "ERA", with an explanation in the
54 ** manual page of what this "time zone abbreviation" means (doing this so
55 ** that tzname[0] has the "normal" length of three characters).
56 */
57 #define WILDABBR " "
58 #endif /* !defined WILDABBR */
59
60 static char wildabbr[] = WILDABBR;
61
62 static const char gmt[] = "GMT";
63
64 /*
65 ** The DST rules to use if TZ has no rules and we can't load TZDEFRULES.
66 ** We default to US rules as of 1999-08-17.
67 ** POSIX 1003.1 section 8.1.1 says that the default DST rules are
68 ** implementation dependent; for historical reasons, US rules are a
69 ** common default.
70 */
71 #ifndef TZDEFRULESTRING
72 #define TZDEFRULESTRING ",M4.1.0,M10.5.0"
73 #endif /* !defined TZDEFDST */
74
75 struct ttinfo { /* time type information */
76 long tt_gmtoff; /* UTC offset in seconds */
77 int tt_isdst; /* used to set tm_isdst */
78 int tt_abbrind; /* abbreviation list index */
79 int tt_ttisstd; /* TRUE if transition is std time */
80 int tt_ttisgmt; /* TRUE if transition is UTC */
81 };
82
83 struct lsinfo { /* leap second information */
84 time_t ls_trans; /* transition time */
85 long ls_corr; /* correction to apply */
86 };
87
88 #define BIGGEST(a, b) (((a) > (b)) ? (a) : (b))
89
90 #ifdef TZNAME_MAX
91 #define MY_TZNAME_MAX TZNAME_MAX
92 #endif /* defined TZNAME_MAX */
93 #ifndef TZNAME_MAX
94 #define MY_TZNAME_MAX 255
95 #endif /* !defined TZNAME_MAX */
96
97 struct state {
98 int leapcnt;
99 int timecnt;
100 int typecnt;
101 int charcnt;
102 int goback;
103 int goahead;
104 time_t ats[TZ_MAX_TIMES];
105 unsigned char types[TZ_MAX_TIMES];
106 struct ttinfo ttis[TZ_MAX_TYPES];
107 char chars[BIGGEST(BIGGEST(TZ_MAX_CHARS + 1, sizeof gmt),
108 (2 * (MY_TZNAME_MAX + 1)))];
109 struct lsinfo lsis[TZ_MAX_LEAPS];
110 };
111
112 struct rule {
113 int r_type; /* type of rule--see below */
114 int r_day; /* day number of rule */
115 int r_week; /* week number of rule */
116 int r_mon; /* month number of rule */
117 long r_time; /* transition time of rule */
118 };
119
120 #define JULIAN_DAY 0 /* Jn - Julian day */
121 #define DAY_OF_YEAR 1 /* n - day of year */
122 #define MONTH_NTH_DAY_OF_WEEK 2 /* Mm.n.d - month, week, day of week */
123
124 /*
125 ** Prototypes for static functions.
126 */
127
128 static long detzcode(const char * codep);
129 static time_t detzcode64(const char * codep);
130 static int differ_by_repeat(time_t t1, time_t t0);
131 static const char * getzname(const char * strp);
132 static const char * getqzname(const char * strp, const int delim);
133 static const char * getnum(const char * strp, int * nump, int min,
134 int max);
135 static const char * getsecs(const char * strp, long * secsp);
136 static const char * getoffset(const char * strp, long * offsetp);
137 static const char * getrule(const char * strp, struct rule * rulep);
138 static void gmtload(struct state * sp);
139 static struct tm * gmtsub(const time_t * timep, long offset,
140 struct tm * tmp);
141 static struct tm * localsub(const time_t * timep, long offset,
142 struct tm * tmp);
143 static int increment_overflow(int * number, int delta);
144 static int leaps_thru_end_of(int y);
145 static int long_increment_overflow(long * number, int delta);
146 static int long_normalize_overflow(long * tensptr,
147 int * unitsptr, int base);
148 static int normalize_overflow(int * tensptr, int * unitsptr,
149 int base);
150 static void settzname(void);
151 static time_t time1(struct tm * tmp,
152 struct tm * (*funcp)(const time_t *,
153 long, struct tm *),
154 long offset);
155 static time_t time2(struct tm *tmp,
156 struct tm * (*funcp)(const time_t *,
157 long, struct tm*),
158 long offset, int * okayp);
159 static time_t time2sub(struct tm *tmp,
160 struct tm * (*funcp)(const time_t *,
161 long, struct tm*),
162 long offset, int * okayp, int do_norm_secs);
163 static struct tm * timesub(const time_t * timep, long offset,
164 const struct state * sp, struct tm * tmp);
165 static int tmcomp(const struct tm * atmp,
166 const struct tm * btmp);
167 static time_t transtime(time_t janfirst, int year,
168 const struct rule * rulep, long offset);
169 static int typesequiv(const struct state * sp, int a, int b);
170 static int tzload(const char * name, struct state * sp,
171 int doextend);
172 static int tzparse(const char * name, struct state * sp,
173 int lastditch);
174
175 #ifdef STD_INSPIRED
176 struct tm *offtime(const time_t *, long);
177 time_t time2posix(time_t);
178 time_t posix2time(time_t);
179 PROTO_DEPRECATED(offtime);
180 PROTO_DEPRECATED(time2posix);
181 PROTO_DEPRECATED(posix2time);
182 #endif
183
184 static struct state * lclptr;
185 static struct state * gmtptr;
186
187
188 #ifndef TZ_STRLEN_MAX
189 #define TZ_STRLEN_MAX 255
190 #endif /* !defined TZ_STRLEN_MAX */
191
192 static int lcl_is_set;
193 static int gmt_is_set;
194 _THREAD_PRIVATE_MUTEX(lcl);
195 _THREAD_PRIVATE_MUTEX(gmt);
196
197 char * tzname[2] = {
198 wildabbr,
199 wildabbr
200 };
201 #if 0
202 DEF_WEAK(tzname);
203 #endif
204
205 /*
206 ** Section 4.12.3 of X3.159-1989 requires that
207 ** Except for the strftime function, these functions [asctime,
208 ** ctime, gmtime, localtime] return values in one of two static
209 ** objects: a broken-down time structure and an array of char.
210 ** Thanks to Paul Eggert for noting this.
211 */
212
213 static struct tm tm;
214
215 long timezone = 0;
216 int daylight = 0;
217
218 static long
detzcode(const char * codep)219 detzcode(const char *codep)
220 {
221 long result;
222 int i;
223
224 result = (codep[0] & 0x80) ? ~0L : 0;
225 for (i = 0; i < 4; ++i)
226 result = (result << 8) | (codep[i] & 0xff);
227 return result;
228 }
229
230 static time_t
detzcode64(const char * codep)231 detzcode64(const char *codep)
232 {
233 time_t result;
234 int i;
235
236 result = (codep[0] & 0x80) ? (~(int_fast64_t) 0) : 0;
237 for (i = 0; i < 8; ++i)
238 result = result * 256 + (codep[i] & 0xff);
239 return result;
240 }
241
242 static void
settzname(void)243 settzname(void)
244 {
245 struct state * const sp = lclptr;
246 int i;
247
248 tzname[0] = wildabbr;
249 tzname[1] = wildabbr;
250 daylight = 0;
251 timezone = 0;
252 if (sp == NULL) {
253 tzname[0] = tzname[1] = (char *)gmt;
254 return;
255 }
256 /*
257 ** And to get the latest zone names into tzname. . .
258 */
259 for (i = 0; i < sp->timecnt; ++i) {
260 const struct ttinfo *ttisp = &sp->ttis[sp->types[i]];
261
262 tzname[ttisp->tt_isdst] = &sp->chars[ttisp->tt_abbrind];
263 if (ttisp->tt_isdst)
264 daylight = 1;
265 if (!ttisp->tt_isdst)
266 timezone = -(ttisp->tt_gmtoff);
267 }
268 /*
269 ** Finally, scrub the abbreviations.
270 ** First, replace bogus characters.
271 */
272 for (i = 0; i < sp->charcnt; ++i) {
273 if (strchr(TZ_ABBR_CHAR_SET, sp->chars[i]) == NULL)
274 sp->chars[i] = TZ_ABBR_ERR_CHAR;
275 }
276 /*
277 ** Second, truncate long abbreviations.
278 */
279 for (i = 0; i < sp->typecnt; ++i) {
280 const struct ttinfo *ttisp = &sp->ttis[i];
281 char *cp = &sp->chars[ttisp->tt_abbrind];
282
283 if (strlen(cp) > TZ_ABBR_MAX_LEN &&
284 strcmp(cp, GRANDPARENTED) != 0)
285 *(cp + TZ_ABBR_MAX_LEN) = '\0';
286 }
287 }
288
289 static int
differ_by_repeat(time_t t1,time_t t0)290 differ_by_repeat(time_t t1, time_t t0)
291 {
292 if (TYPE_BIT(time_t) - 1 < SECSPERREPEAT_BITS)
293 return 0;
294 return (int64_t)t1 - t0 == SECSPERREPEAT;
295 }
296
297 static int
tzpath_ok(const char * name)298 tzpath_ok(const char *name)
299 {
300 /* Reject absolute paths that don't start with TZDIR. */
301 if (name[0] == '/' && (strncmp(name, TZDIR, sizeof(TZDIR) - 1) != 0 ||
302 name[sizeof(TZDIR) - 1] != '/'))
303 return 0;
304
305 /* Reject paths that contain "../". */
306 if (strstr(name, "../") != NULL)
307 return 0;
308
309 return 1;
310 }
311
312 static int
open_tzfile(const char * name)313 open_tzfile(const char *name)
314 {
315 char fullname[PATH_MAX];
316 int i;
317
318 if (name != NULL) {
319 /*
320 * POSIX section 8 says that names starting with a ':' are
321 * "implementation-defined". We treat them as timezone paths.
322 */
323 if (name[0] == ':')
324 name++;
325
326 /*
327 * Ignore absolute paths that don't start with TZDIR
328 * or that contain "../".
329 */
330 if (!tzpath_ok(name))
331 name = NULL;
332 }
333
334 if (name == NULL) {
335 name = TZDEFAULT;
336 } else if (name[0] != '/') {
337 /* Time zone data path is relative to TZDIR. */
338 i = snprintf(fullname, sizeof(fullname), "%s/%s", TZDIR, name);
339 if (i < 0 || i >= sizeof(fullname)) {
340 errno = ENAMETOOLONG;
341 return -1;
342 }
343 name = fullname;
344 }
345
346 return open(name, O_RDONLY);
347 }
348
349 static int
tzload(const char * name,struct state * sp,int doextend)350 tzload(const char *name, struct state *sp, int doextend)
351 {
352 const char * p;
353 int i;
354 int fid;
355 int stored;
356 int nread;
357 typedef union {
358 struct tzhead tzhead;
359 char buf[2 * sizeof(struct tzhead) +
360 2 * sizeof *sp +
361 4 * TZ_MAX_TIMES];
362 } u_t;
363 u_t * up;
364
365 up = calloc(1, sizeof *up);
366 if (up == NULL)
367 return -1;
368
369 sp->goback = sp->goahead = FALSE;
370
371 if ((fid = open_tzfile(name)) == -1) {
372 /* Could be a POSIX section 8-style TZ string. */
373 goto oops;
374 }
375
376 nread = read(fid, up->buf, sizeof up->buf);
377 if (close(fid) == -1 || nread <= 0)
378 goto oops;
379 for (stored = 4; stored <= 8; stored *= 2) {
380 int ttisstdcnt;
381 int ttisgmtcnt;
382
383 ttisstdcnt = (int) detzcode(up->tzhead.tzh_ttisstdcnt);
384 ttisgmtcnt = (int) detzcode(up->tzhead.tzh_ttisgmtcnt);
385 sp->leapcnt = (int) detzcode(up->tzhead.tzh_leapcnt);
386 sp->timecnt = (int) detzcode(up->tzhead.tzh_timecnt);
387 sp->typecnt = (int) detzcode(up->tzhead.tzh_typecnt);
388 sp->charcnt = (int) detzcode(up->tzhead.tzh_charcnt);
389 p = up->tzhead.tzh_charcnt + sizeof up->tzhead.tzh_charcnt;
390 if (sp->leapcnt < 0 || sp->leapcnt > TZ_MAX_LEAPS ||
391 sp->typecnt <= 0 || sp->typecnt > TZ_MAX_TYPES ||
392 sp->timecnt < 0 || sp->timecnt > TZ_MAX_TIMES ||
393 sp->charcnt < 0 || sp->charcnt > TZ_MAX_CHARS ||
394 (ttisstdcnt != sp->typecnt && ttisstdcnt != 0) ||
395 (ttisgmtcnt != sp->typecnt && ttisgmtcnt != 0))
396 goto oops;
397 if (nread - (p - up->buf) <
398 sp->timecnt * stored + /* ats */
399 sp->timecnt + /* types */
400 sp->typecnt * 6 + /* ttinfos */
401 sp->charcnt + /* chars */
402 sp->leapcnt * (stored + 4) + /* lsinfos */
403 ttisstdcnt + /* ttisstds */
404 ttisgmtcnt) /* ttisgmts */
405 goto oops;
406 for (i = 0; i < sp->timecnt; ++i) {
407 sp->ats[i] = (stored == 4) ?
408 detzcode(p) : detzcode64(p);
409 p += stored;
410 }
411 for (i = 0; i < sp->timecnt; ++i) {
412 sp->types[i] = (unsigned char) *p++;
413 if (sp->types[i] >= sp->typecnt)
414 goto oops;
415 }
416 for (i = 0; i < sp->typecnt; ++i) {
417 struct ttinfo * ttisp;
418
419 ttisp = &sp->ttis[i];
420 ttisp->tt_gmtoff = detzcode(p);
421 p += 4;
422 ttisp->tt_isdst = (unsigned char) *p++;
423 if (ttisp->tt_isdst != 0 && ttisp->tt_isdst != 1)
424 goto oops;
425 ttisp->tt_abbrind = (unsigned char) *p++;
426 if (ttisp->tt_abbrind < 0 ||
427 ttisp->tt_abbrind > sp->charcnt)
428 goto oops;
429 }
430 for (i = 0; i < sp->charcnt; ++i)
431 sp->chars[i] = *p++;
432 sp->chars[i] = '\0'; /* ensure '\0' at end */
433 for (i = 0; i < sp->leapcnt; ++i) {
434 struct lsinfo * lsisp;
435
436 lsisp = &sp->lsis[i];
437 lsisp->ls_trans = (stored == 4) ?
438 detzcode(p) : detzcode64(p);
439 p += stored;
440 lsisp->ls_corr = detzcode(p);
441 p += 4;
442 }
443 for (i = 0; i < sp->typecnt; ++i) {
444 struct ttinfo * ttisp;
445
446 ttisp = &sp->ttis[i];
447 if (ttisstdcnt == 0)
448 ttisp->tt_ttisstd = FALSE;
449 else {
450 ttisp->tt_ttisstd = *p++;
451 if (ttisp->tt_ttisstd != TRUE &&
452 ttisp->tt_ttisstd != FALSE)
453 goto oops;
454 }
455 }
456 for (i = 0; i < sp->typecnt; ++i) {
457 struct ttinfo * ttisp;
458
459 ttisp = &sp->ttis[i];
460 if (ttisgmtcnt == 0)
461 ttisp->tt_ttisgmt = FALSE;
462 else {
463 ttisp->tt_ttisgmt = *p++;
464 if (ttisp->tt_ttisgmt != TRUE &&
465 ttisp->tt_ttisgmt != FALSE)
466 goto oops;
467 }
468 }
469 /*
470 ** Out-of-sort ats should mean we're running on a
471 ** signed time_t system but using a data file with
472 ** unsigned values (or vice versa).
473 */
474 for (i = 0; i < sp->timecnt - 2; ++i)
475 if (sp->ats[i] > sp->ats[i + 1]) {
476 ++i;
477 /*
478 ** Ignore the end (easy).
479 */
480 sp->timecnt = i;
481 break;
482 }
483 /*
484 ** If this is an old file, we're done.
485 */
486 if (up->tzhead.tzh_version[0] == '\0')
487 break;
488 nread -= p - up->buf;
489 for (i = 0; i < nread; ++i)
490 up->buf[i] = p[i];
491 /*
492 ** If this is a narrow integer time_t system, we're done.
493 */
494 if (stored >= sizeof(time_t))
495 break;
496 }
497 if (doextend && nread > 2 &&
498 up->buf[0] == '\n' && up->buf[nread - 1] == '\n' &&
499 sp->typecnt + 2 <= TZ_MAX_TYPES) {
500 struct state ts;
501 int result;
502
503 up->buf[nread - 1] = '\0';
504 result = tzparse(&up->buf[1], &ts, FALSE);
505 if (result == 0 && ts.typecnt == 2 &&
506 sp->charcnt + ts.charcnt <= TZ_MAX_CHARS) {
507 for (i = 0; i < 2; ++i)
508 ts.ttis[i].tt_abbrind +=
509 sp->charcnt;
510 for (i = 0; i < ts.charcnt; ++i)
511 sp->chars[sp->charcnt++] =
512 ts.chars[i];
513 i = 0;
514 while (i < ts.timecnt &&
515 ts.ats[i] <=
516 sp->ats[sp->timecnt - 1])
517 ++i;
518 while (i < ts.timecnt &&
519 sp->timecnt < TZ_MAX_TIMES) {
520 sp->ats[sp->timecnt] =
521 ts.ats[i];
522 sp->types[sp->timecnt] =
523 sp->typecnt +
524 ts.types[i];
525 ++sp->timecnt;
526 ++i;
527 }
528 sp->ttis[sp->typecnt++] = ts.ttis[0];
529 sp->ttis[sp->typecnt++] = ts.ttis[1];
530 }
531 }
532 if (sp->timecnt > 1) {
533 for (i = 1; i < sp->timecnt; ++i) {
534 if (typesequiv(sp, sp->types[i], sp->types[0]) &&
535 differ_by_repeat(sp->ats[i], sp->ats[0])) {
536 sp->goback = TRUE;
537 break;
538 }
539 }
540 for (i = sp->timecnt - 2; i >= 0; --i) {
541 if (typesequiv(sp, sp->types[sp->timecnt - 1],
542 sp->types[i]) &&
543 differ_by_repeat(sp->ats[sp->timecnt - 1],
544 sp->ats[i])) {
545 sp->goahead = TRUE;
546 break;
547 }
548 }
549 }
550 free(up);
551 return 0;
552 oops:
553 free(up);
554 return -1;
555 }
556
557 static int
typesequiv(const struct state * sp,int a,int b)558 typesequiv(const struct state *sp, int a, int b)
559 {
560 int result;
561
562 if (sp == NULL ||
563 a < 0 || a >= sp->typecnt ||
564 b < 0 || b >= sp->typecnt)
565 result = FALSE;
566 else {
567 const struct ttinfo * ap = &sp->ttis[a];
568 const struct ttinfo * bp = &sp->ttis[b];
569 result = ap->tt_gmtoff == bp->tt_gmtoff &&
570 ap->tt_isdst == bp->tt_isdst &&
571 ap->tt_ttisstd == bp->tt_ttisstd &&
572 ap->tt_ttisgmt == bp->tt_ttisgmt &&
573 strcmp(&sp->chars[ap->tt_abbrind],
574 &sp->chars[bp->tt_abbrind]) == 0;
575 }
576 return result;
577 }
578
579 static const int mon_lengths[2][MONSPERYEAR] = {
580 { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 },
581 { 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }
582 };
583
584 static const int year_lengths[2] = {
585 DAYSPERNYEAR, DAYSPERLYEAR
586 };
587
588 /*
589 ** Given a pointer into a time zone string, scan until a character that is not
590 ** a valid character in a zone name is found. Return a pointer to that
591 ** character.
592 */
593
594 static const char *
getzname(const char * strp)595 getzname(const char *strp)
596 {
597 char c;
598
599 while ((c = *strp) != '\0' && !isdigit((unsigned char)c) && c != ',' && c != '-' &&
600 c != '+')
601 ++strp;
602 return strp;
603 }
604
605 /*
606 ** Given a pointer into an extended time zone string, scan until the ending
607 ** delimiter of the zone name is located. Return a pointer to the delimiter.
608 **
609 ** As with getzname above, the legal character set is actually quite
610 ** restricted, with other characters producing undefined results.
611 ** We don't do any checking here; checking is done later in common-case code.
612 */
613
614 static const char *
getqzname(const char * strp,const int delim)615 getqzname(const char *strp, const int delim)
616 {
617 int c;
618
619 while ((c = *strp) != '\0' && c != delim)
620 ++strp;
621 return strp;
622 }
623
624 /*
625 ** Given a pointer into a time zone string, extract a number from that string.
626 ** Check that the number is within a specified range; if it is not, return
627 ** NULL.
628 ** Otherwise, return a pointer to the first character not part of the number.
629 */
630
631 static const char *
getnum(const char * strp,int * nump,int min,int max)632 getnum(const char *strp, int *nump, int min, int max)
633 {
634 char c;
635 int num;
636
637 if (strp == NULL || !isdigit((unsigned char)(c = *strp)))
638 return NULL;
639 num = 0;
640 do {
641 num = num * 10 + (c - '0');
642 if (num > max)
643 return NULL; /* illegal value */
644 c = *++strp;
645 } while (isdigit((unsigned char)c));
646 if (num < min)
647 return NULL; /* illegal value */
648 *nump = num;
649 return strp;
650 }
651
652 /*
653 ** Given a pointer into a time zone string, extract a number of seconds,
654 ** in hh[:mm[:ss]] form, from the string.
655 ** If any error occurs, return NULL.
656 ** Otherwise, return a pointer to the first character not part of the number
657 ** of seconds.
658 */
659
660 static const char *
getsecs(const char * strp,long * secsp)661 getsecs(const char *strp, long *secsp)
662 {
663 int num;
664
665 /*
666 ** `HOURSPERDAY * DAYSPERWEEK - 1' allows quasi-Posix rules like
667 ** "M10.4.6/26", which does not conform to Posix,
668 ** but which specifies the equivalent of
669 ** ``02:00 on the first Sunday on or after 23 Oct''.
670 */
671 strp = getnum(strp, &num, 0, HOURSPERDAY * DAYSPERWEEK - 1);
672 if (strp == NULL)
673 return NULL;
674 *secsp = num * (long) SECSPERHOUR;
675 if (*strp == ':') {
676 ++strp;
677 strp = getnum(strp, &num, 0, MINSPERHOUR - 1);
678 if (strp == NULL)
679 return NULL;
680 *secsp += num * SECSPERMIN;
681 if (*strp == ':') {
682 ++strp;
683 /* `SECSPERMIN' allows for leap seconds. */
684 strp = getnum(strp, &num, 0, SECSPERMIN);
685 if (strp == NULL)
686 return NULL;
687 *secsp += num;
688 }
689 }
690 return strp;
691 }
692
693 /*
694 ** Given a pointer into a time zone string, extract an offset, in
695 ** [+-]hh[:mm[:ss]] form, from the string.
696 ** If any error occurs, return NULL.
697 ** Otherwise, return a pointer to the first character not part of the time.
698 */
699
700 static const char *
getoffset(const char * strp,long * offsetp)701 getoffset(const char *strp, long *offsetp)
702 {
703 int neg = 0;
704
705 if (*strp == '-') {
706 neg = 1;
707 ++strp;
708 } else if (*strp == '+')
709 ++strp;
710 strp = getsecs(strp, offsetp);
711 if (strp == NULL)
712 return NULL; /* illegal time */
713 if (neg)
714 *offsetp = -*offsetp;
715 return strp;
716 }
717
718 /*
719 ** Given a pointer into a time zone string, extract a rule in the form
720 ** date[/time]. See POSIX section 8 for the format of "date" and "time".
721 ** If a valid rule is not found, return NULL.
722 ** Otherwise, return a pointer to the first character not part of the rule.
723 */
724
725 static const char *
getrule(const char * strp,struct rule * rulep)726 getrule(const char *strp, struct rule *rulep)
727 {
728 if (*strp == 'J') {
729 /*
730 ** Julian day.
731 */
732 rulep->r_type = JULIAN_DAY;
733 ++strp;
734 strp = getnum(strp, &rulep->r_day, 1, DAYSPERNYEAR);
735 } else if (*strp == 'M') {
736 /*
737 ** Month, week, day.
738 */
739 rulep->r_type = MONTH_NTH_DAY_OF_WEEK;
740 ++strp;
741 strp = getnum(strp, &rulep->r_mon, 1, MONSPERYEAR);
742 if (strp == NULL)
743 return NULL;
744 if (*strp++ != '.')
745 return NULL;
746 strp = getnum(strp, &rulep->r_week, 1, 5);
747 if (strp == NULL)
748 return NULL;
749 if (*strp++ != '.')
750 return NULL;
751 strp = getnum(strp, &rulep->r_day, 0, DAYSPERWEEK - 1);
752 } else if (isdigit((unsigned char)*strp)) {
753 /*
754 ** Day of year.
755 */
756 rulep->r_type = DAY_OF_YEAR;
757 strp = getnum(strp, &rulep->r_day, 0, DAYSPERLYEAR - 1);
758 } else
759 return NULL; /* invalid format */
760 if (strp == NULL)
761 return NULL;
762 if (*strp == '/') {
763 /*
764 ** Time specified.
765 */
766 ++strp;
767 strp = getsecs(strp, &rulep->r_time);
768 } else
769 rulep->r_time = 2 * SECSPERHOUR; /* default = 2:00:00 */
770 return strp;
771 }
772
773 /*
774 ** Given the Epoch-relative time of January 1, 00:00:00 UTC, in a year, the
775 ** year, a rule, and the offset from UTC at the time that rule takes effect,
776 ** calculate the Epoch-relative time that rule takes effect.
777 */
778
779 static time_t
transtime(time_t janfirst,int year,const struct rule * rulep,long offset)780 transtime(time_t janfirst, int year, const struct rule *rulep, long offset)
781 {
782 int leapyear;
783 time_t value;
784 int i;
785 int d, m1, yy0, yy1, yy2, dow;
786
787 value = 0;
788 leapyear = isleap(year);
789 switch (rulep->r_type) {
790
791 case JULIAN_DAY:
792 /*
793 ** Jn - Julian day, 1 == January 1, 60 == March 1 even in leap
794 ** years.
795 ** In non-leap years, or if the day number is 59 or less, just
796 ** add SECSPERDAY times the day number-1 to the time of
797 ** January 1, midnight, to get the day.
798 */
799 value = janfirst + (rulep->r_day - 1) * SECSPERDAY;
800 if (leapyear && rulep->r_day >= 60)
801 value += SECSPERDAY;
802 break;
803
804 case DAY_OF_YEAR:
805 /*
806 ** n - day of year.
807 ** Just add SECSPERDAY times the day number to the time of
808 ** January 1, midnight, to get the day.
809 */
810 value = janfirst + rulep->r_day * SECSPERDAY;
811 break;
812
813 case MONTH_NTH_DAY_OF_WEEK:
814 /*
815 ** Mm.n.d - nth "dth day" of month m.
816 */
817 value = janfirst;
818 for (i = 0; i < rulep->r_mon - 1; ++i)
819 value += mon_lengths[leapyear][i] * SECSPERDAY;
820
821 /*
822 ** Use Zeller's Congruence to get day-of-week of first day of
823 ** month.
824 */
825 m1 = (rulep->r_mon + 9) % 12 + 1;
826 yy0 = (rulep->r_mon <= 2) ? (year - 1) : year;
827 yy1 = yy0 / 100;
828 yy2 = yy0 % 100;
829 dow = ((26 * m1 - 2) / 10 +
830 1 + yy2 + yy2 / 4 + yy1 / 4 - 2 * yy1) % 7;
831 if (dow < 0)
832 dow += DAYSPERWEEK;
833
834 /*
835 ** "dow" is the day-of-week of the first day of the month. Get
836 ** the day-of-month (zero-origin) of the first "dow" day of the
837 ** month.
838 */
839 d = rulep->r_day - dow;
840 if (d < 0)
841 d += DAYSPERWEEK;
842 for (i = 1; i < rulep->r_week; ++i) {
843 if (d + DAYSPERWEEK >=
844 mon_lengths[leapyear][rulep->r_mon - 1])
845 break;
846 d += DAYSPERWEEK;
847 }
848
849 /*
850 ** "d" is the day-of-month (zero-origin) of the day we want.
851 */
852 value += d * SECSPERDAY;
853 break;
854 }
855
856 /*
857 ** "value" is the Epoch-relative time of 00:00:00 UTC on the day in
858 ** question. To get the Epoch-relative time of the specified local
859 ** time on that day, add the transition time and the current offset
860 ** from UTC.
861 */
862 return value + rulep->r_time + offset;
863 }
864
865 /*
866 ** Given a POSIX section 8-style TZ string, fill in the rule tables as
867 ** appropriate.
868 */
869
870 static int
tzparse(const char * name,struct state * sp,int lastditch)871 tzparse(const char *name, struct state *sp, int lastditch)
872 {
873 const char * stdname;
874 const char * dstname;
875 size_t stdlen;
876 size_t dstlen;
877 long stdoffset;
878 long dstoffset;
879 time_t * atp;
880 unsigned char * typep;
881 char * cp;
882 int load_result;
883 static struct ttinfo zttinfo;
884
885 dstname = NULL;
886 stdname = name;
887 if (lastditch) {
888 stdlen = strlen(name); /* length of standard zone name */
889 name += stdlen;
890 if (stdlen >= sizeof sp->chars)
891 stdlen = (sizeof sp->chars) - 1;
892 stdoffset = 0;
893 } else {
894 if (*name == '<') {
895 name++;
896 stdname = name;
897 name = getqzname(name, '>');
898 if (*name != '>')
899 return (-1);
900 stdlen = name - stdname;
901 name++;
902 } else {
903 name = getzname(name);
904 stdlen = name - stdname;
905 }
906 if (*name == '\0')
907 return -1;
908 name = getoffset(name, &stdoffset);
909 if (name == NULL)
910 return -1;
911 }
912 load_result = tzload(TZDEFRULES, sp, FALSE);
913 if (load_result != 0)
914 sp->leapcnt = 0; /* so, we're off a little */
915 if (*name != '\0') {
916 if (*name == '<') {
917 dstname = ++name;
918 name = getqzname(name, '>');
919 if (*name != '>')
920 return -1;
921 dstlen = name - dstname;
922 name++;
923 } else {
924 dstname = name;
925 name = getzname(name);
926 dstlen = name - dstname; /* length of DST zone name */
927 }
928 if (*name != '\0' && *name != ',' && *name != ';') {
929 name = getoffset(name, &dstoffset);
930 if (name == NULL)
931 return -1;
932 } else
933 dstoffset = stdoffset - SECSPERHOUR;
934 if (*name == '\0' && load_result != 0)
935 name = TZDEFRULESTRING;
936 if (*name == ',' || *name == ';') {
937 struct rule start;
938 struct rule end;
939 int year;
940 time_t janfirst;
941 time_t starttime;
942 time_t endtime;
943
944 ++name;
945 if ((name = getrule(name, &start)) == NULL)
946 return -1;
947 if (*name++ != ',')
948 return -1;
949 if ((name = getrule(name, &end)) == NULL)
950 return -1;
951 if (*name != '\0')
952 return -1;
953 sp->typecnt = 2; /* standard time and DST */
954 /*
955 ** Two transitions per year, from EPOCH_YEAR forward.
956 */
957 sp->ttis[0] = sp->ttis[1] = zttinfo;
958 sp->ttis[0].tt_gmtoff = -dstoffset;
959 sp->ttis[0].tt_isdst = 1;
960 sp->ttis[0].tt_abbrind = stdlen + 1;
961 sp->ttis[1].tt_gmtoff = -stdoffset;
962 sp->ttis[1].tt_isdst = 0;
963 sp->ttis[1].tt_abbrind = 0;
964 atp = sp->ats;
965 typep = sp->types;
966 janfirst = 0;
967 sp->timecnt = 0;
968 for (year = EPOCH_YEAR;
969 sp->timecnt + 2 <= TZ_MAX_TIMES;
970 ++year) {
971 time_t newfirst;
972
973 starttime = transtime(janfirst, year, &start,
974 stdoffset);
975 endtime = transtime(janfirst, year, &end,
976 dstoffset);
977 if (starttime > endtime) {
978 *atp++ = endtime;
979 *typep++ = 1; /* DST ends */
980 *atp++ = starttime;
981 *typep++ = 0; /* DST begins */
982 } else {
983 *atp++ = starttime;
984 *typep++ = 0; /* DST begins */
985 *atp++ = endtime;
986 *typep++ = 1; /* DST ends */
987 }
988 sp->timecnt += 2;
989 newfirst = janfirst;
990 newfirst += year_lengths[isleap(year)] *
991 SECSPERDAY;
992 if (newfirst <= janfirst)
993 break;
994 janfirst = newfirst;
995 }
996 } else {
997 long theirstdoffset;
998 long theirdstoffset;
999 long theiroffset;
1000 int isdst;
1001 int i;
1002 int j;
1003
1004 if (*name != '\0')
1005 return -1;
1006 /*
1007 ** Initial values of theirstdoffset and theirdstoffset.
1008 */
1009 theirstdoffset = 0;
1010 for (i = 0; i < sp->timecnt; ++i) {
1011 j = sp->types[i];
1012 if (!sp->ttis[j].tt_isdst) {
1013 theirstdoffset =
1014 -sp->ttis[j].tt_gmtoff;
1015 break;
1016 }
1017 }
1018 theirdstoffset = 0;
1019 for (i = 0; i < sp->timecnt; ++i) {
1020 j = sp->types[i];
1021 if (sp->ttis[j].tt_isdst) {
1022 theirdstoffset =
1023 -sp->ttis[j].tt_gmtoff;
1024 break;
1025 }
1026 }
1027 /*
1028 ** Initially we're assumed to be in standard time.
1029 */
1030 isdst = FALSE;
1031 theiroffset = theirstdoffset;
1032 /*
1033 ** Now juggle transition times and types
1034 ** tracking offsets as you do.
1035 */
1036 for (i = 0; i < sp->timecnt; ++i) {
1037 j = sp->types[i];
1038 sp->types[i] = sp->ttis[j].tt_isdst;
1039 if (sp->ttis[j].tt_ttisgmt) {
1040 /* No adjustment to transition time */
1041 } else {
1042 /*
1043 ** If summer time is in effect, and the
1044 ** transition time was not specified as
1045 ** standard time, add the summer time
1046 ** offset to the transition time;
1047 ** otherwise, add the standard time
1048 ** offset to the transition time.
1049 */
1050 /*
1051 ** Transitions from DST to DDST
1052 ** will effectively disappear since
1053 ** POSIX provides for only one DST
1054 ** offset.
1055 */
1056 if (isdst && !sp->ttis[j].tt_ttisstd) {
1057 sp->ats[i] += dstoffset -
1058 theirdstoffset;
1059 } else {
1060 sp->ats[i] += stdoffset -
1061 theirstdoffset;
1062 }
1063 }
1064 theiroffset = -sp->ttis[j].tt_gmtoff;
1065 if (sp->ttis[j].tt_isdst)
1066 theirdstoffset = theiroffset;
1067 else
1068 theirstdoffset = theiroffset;
1069 }
1070 /*
1071 ** Finally, fill in ttis.
1072 */
1073 sp->ttis[0] = sp->ttis[1] = zttinfo;
1074 sp->ttis[0].tt_gmtoff = -stdoffset;
1075 sp->ttis[0].tt_isdst = FALSE;
1076 sp->ttis[0].tt_abbrind = 0;
1077 sp->ttis[1].tt_gmtoff = -dstoffset;
1078 sp->ttis[1].tt_isdst = TRUE;
1079 sp->ttis[1].tt_abbrind = stdlen + 1;
1080 sp->typecnt = 2;
1081 }
1082 } else {
1083 dstlen = 0;
1084 sp->typecnt = 1; /* only standard time */
1085 sp->timecnt = 0;
1086 sp->ttis[0] = zttinfo;
1087 sp->ttis[0].tt_gmtoff = -stdoffset;
1088 sp->ttis[0].tt_isdst = 0;
1089 sp->ttis[0].tt_abbrind = 0;
1090 }
1091 sp->charcnt = stdlen + 1;
1092 if (dstlen != 0)
1093 sp->charcnt += dstlen + 1;
1094 if ((size_t) sp->charcnt > sizeof sp->chars)
1095 return -1;
1096 cp = sp->chars;
1097 strlcpy(cp, stdname, stdlen + 1);
1098 cp += stdlen + 1;
1099 if (dstlen != 0) {
1100 strlcpy(cp, dstname, dstlen + 1);
1101 }
1102 return 0;
1103 }
1104
1105 static void
gmtload(struct state * sp)1106 gmtload(struct state *sp)
1107 {
1108 if (tzload(gmt, sp, TRUE) != 0)
1109 (void) tzparse(gmt, sp, TRUE);
1110 }
1111
1112 static void
tzsetwall_basic(void)1113 tzsetwall_basic(void)
1114 {
1115 if (lcl_is_set < 0)
1116 return;
1117 lcl_is_set = -1;
1118
1119 if (lclptr == NULL) {
1120 lclptr = calloc(1, sizeof *lclptr);
1121 if (lclptr == NULL) {
1122 settzname(); /* all we can do */
1123 return;
1124 }
1125 }
1126 if (tzload(NULL, lclptr, TRUE) != 0)
1127 gmtload(lclptr);
1128 settzname();
1129 }
1130
1131 #ifndef STD_INSPIRED
1132 /*
1133 ** A non-static declaration of tzsetwall in a system header file
1134 ** may cause a warning about this upcoming static declaration...
1135 */
1136 static
1137 #endif /* !defined STD_INSPIRED */
1138 void
tzsetwall(void)1139 tzsetwall(void)
1140 {
1141 _THREAD_PRIVATE_MUTEX_LOCK(lcl);
1142 tzsetwall_basic();
1143 _THREAD_PRIVATE_MUTEX_UNLOCK(lcl);
1144 }
1145
1146 static void
tzset_basic(void)1147 tzset_basic(void)
1148 {
1149 static char lcl_TZname[TZ_STRLEN_MAX + 1];
1150 const char * name;
1151
1152 name = getenv("TZ");
1153 if (name == NULL) {
1154 tzsetwall_basic();
1155 return;
1156 }
1157
1158 if (lcl_is_set > 0 && strcmp(lcl_TZname, name) == 0)
1159 return;
1160 lcl_is_set = strlen(name) < sizeof lcl_TZname;
1161 if (lcl_is_set)
1162 strlcpy(lcl_TZname, name, sizeof lcl_TZname);
1163
1164 /* Ignore TZ for setuid/setgid processes. */
1165 if (issetugid())
1166 name = TZDEFAULT;
1167
1168 if (lclptr == NULL) {
1169 lclptr = calloc(1, sizeof *lclptr);
1170 if (lclptr == NULL) {
1171 settzname(); /* all we can do */
1172 return;
1173 }
1174 }
1175 if (*name == '\0') {
1176 /*
1177 ** User wants it fast rather than right.
1178 */
1179 lclptr->leapcnt = 0; /* so, we're off a little */
1180 lclptr->timecnt = 0;
1181 lclptr->typecnt = 0;
1182 lclptr->ttis[0].tt_isdst = 0;
1183 lclptr->ttis[0].tt_gmtoff = 0;
1184 lclptr->ttis[0].tt_abbrind = 0;
1185 strlcpy(lclptr->chars, gmt, sizeof lclptr->chars);
1186 } else if (tzload(name, lclptr, TRUE) != 0) {
1187 if (name[0] == ':' || tzparse(name, lclptr, FALSE) != 0)
1188 gmtload(lclptr);
1189 }
1190 settzname();
1191 }
1192
1193 void
tzset(void)1194 tzset(void)
1195 {
1196 _THREAD_PRIVATE_MUTEX_LOCK(lcl);
1197 tzset_basic();
1198 _THREAD_PRIVATE_MUTEX_UNLOCK(lcl);
1199 }
1200 DEF_WEAK(tzset);
1201
1202 /*
1203 ** The easy way to behave "as if no library function calls" localtime
1204 ** is to not call it--so we drop its guts into "localsub", which can be
1205 ** freely called. (And no, the PANS doesn't require the above behavior--
1206 ** but it *is* desirable.)
1207 **
1208 ** The unused offset argument is for the benefit of mktime variants.
1209 */
1210
1211 static struct tm *
localsub(const time_t * timep,long offset,struct tm * tmp)1212 localsub(const time_t *timep, long offset, struct tm *tmp)
1213 {
1214 struct state * sp;
1215 const struct ttinfo * ttisp;
1216 int i;
1217 struct tm * result;
1218 const time_t t = *timep;
1219
1220 sp = lclptr;
1221 if (sp == NULL)
1222 return gmtsub(timep, offset, tmp);
1223 if ((sp->goback && t < sp->ats[0]) ||
1224 (sp->goahead && t > sp->ats[sp->timecnt - 1])) {
1225 time_t newt = t;
1226 time_t seconds;
1227 time_t tcycles;
1228 int_fast64_t icycles;
1229
1230 if (t < sp->ats[0])
1231 seconds = sp->ats[0] - t;
1232 else
1233 seconds = t - sp->ats[sp->timecnt - 1];
1234 --seconds;
1235 tcycles = seconds / YEARSPERREPEAT / AVGSECSPERYEAR;
1236 ++tcycles;
1237 icycles = tcycles;
1238 if (tcycles - icycles >= 1 || icycles - tcycles >= 1)
1239 return NULL;
1240 seconds = icycles;
1241 seconds *= YEARSPERREPEAT;
1242 seconds *= AVGSECSPERYEAR;
1243 if (t < sp->ats[0])
1244 newt += seconds;
1245 else
1246 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
1258 newy += icycles * YEARSPERREPEAT;
1259 tmp->tm_year = newy;
1260 if (tmp->tm_year != newy)
1261 return NULL;
1262 }
1263 return result;
1264 }
1265 if (sp->timecnt == 0 || t < sp->ats[0]) {
1266 i = 0;
1267 while (sp->ttis[i].tt_isdst) {
1268 if (++i >= sp->typecnt) {
1269 i = 0;
1270 break;
1271 }
1272 }
1273 } else {
1274 int lo = 1;
1275 int hi = sp->timecnt;
1276
1277 while (lo < hi) {
1278 int mid = (lo + hi) >> 1;
1279
1280 if (t < sp->ats[mid])
1281 hi = mid;
1282 else
1283 lo = mid + 1;
1284 }
1285 i = (int) sp->types[lo - 1];
1286 }
1287 ttisp = &sp->ttis[i];
1288 /*
1289 ** To get (wrong) behavior that's compatible with System V Release 2.0
1290 ** you'd replace the statement below with
1291 ** t += ttisp->tt_gmtoff;
1292 ** timesub(&t, 0L, sp, tmp);
1293 */
1294 result = timesub(&t, ttisp->tt_gmtoff, sp, tmp);
1295 tmp->tm_isdst = ttisp->tt_isdst;
1296 tzname[tmp->tm_isdst] = &sp->chars[ttisp->tt_abbrind];
1297 tmp->tm_zone = &sp->chars[ttisp->tt_abbrind];
1298 return result;
1299 }
1300
1301 /*
1302 ** Re-entrant version of localtime.
1303 */
1304
1305 struct tm *
localtime_r(const time_t * timep,struct tm * p_tm)1306 localtime_r(const time_t *timep, struct tm *p_tm)
1307 {
1308 _THREAD_PRIVATE_MUTEX_LOCK(lcl);
1309 tzset_basic();
1310 p_tm = localsub(timep, 0L, p_tm);
1311 _THREAD_PRIVATE_MUTEX_UNLOCK(lcl);
1312 return p_tm;
1313 }
1314 DEF_WEAK(localtime_r);
1315
1316 struct tm *
localtime(const time_t * timep)1317 localtime(const time_t *timep)
1318 {
1319 _THREAD_PRIVATE_KEY(localtime);
1320 struct tm * p_tm = (struct tm*)_THREAD_PRIVATE(localtime, tm, NULL);
1321
1322 if (p_tm == NULL)
1323 return NULL;
1324 return localtime_r(timep, p_tm);
1325 }
1326 DEF_STRONG(localtime);
1327
1328 /*
1329 ** gmtsub is to gmtime as localsub is to localtime.
1330 */
1331
1332 static struct tm *
gmtsub(const time_t * timep,long offset,struct tm * tmp)1333 gmtsub(const time_t *timep, long offset, struct tm *tmp)
1334 {
1335 struct tm * result;
1336
1337 _THREAD_PRIVATE_MUTEX_LOCK(gmt);
1338 if (!gmt_is_set) {
1339 gmt_is_set = TRUE;
1340 gmtptr = calloc(1, sizeof(*gmtptr));
1341 if (gmtptr != NULL)
1342 gmtload(gmtptr);
1343 }
1344 _THREAD_PRIVATE_MUTEX_UNLOCK(gmt);
1345 result = timesub(timep, offset, gmtptr, tmp);
1346 /*
1347 ** Could get fancy here and deliver something such as
1348 ** "UTC+xxxx" or "UTC-xxxx" if offset is non-zero,
1349 ** but this is no time for a treasure hunt.
1350 */
1351 if (offset != 0)
1352 tmp->tm_zone = wildabbr;
1353 else {
1354 if (gmtptr == NULL)
1355 tmp->tm_zone = (char *)gmt;
1356 else
1357 tmp->tm_zone = gmtptr->chars;
1358 }
1359 return result;
1360 }
1361
1362 /*
1363 ** Re-entrant version of gmtime.
1364 */
1365
1366 struct tm *
gmtime_r(const time_t * timep,struct tm * p_tm)1367 gmtime_r(const time_t *timep, struct tm *p_tm)
1368 {
1369 return gmtsub(timep, 0L, p_tm);
1370 }
1371 DEF_WEAK(gmtime_r);
1372
1373 struct tm *
gmtime(const time_t * timep)1374 gmtime(const time_t *timep)
1375 {
1376 _THREAD_PRIVATE_KEY(gmtime);
1377 struct tm * p_tm = (struct tm*) _THREAD_PRIVATE(gmtime, tm, NULL);
1378
1379 if (p_tm == NULL)
1380 return NULL;
1381 return gmtime_r(timep, p_tm);
1382
1383 }
1384 DEF_WEAK(gmtime);
1385
1386 #ifdef STD_INSPIRED
1387
1388 struct tm *
offtime(const time_t * timep,long offset)1389 offtime(const time_t *timep, long offset)
1390 {
1391 return gmtsub(timep, offset, &tm);
1392 }
1393
1394 #endif /* defined STD_INSPIRED */
1395
1396 /*
1397 ** Return the number of leap years through the end of the given year
1398 ** where, to make the math easy, the answer for year zero is defined as zero.
1399 */
1400
1401 static int
leaps_thru_end_of(int y)1402 leaps_thru_end_of(int y)
1403 {
1404 return (y >= 0) ? (y / 4 - y / 100 + y / 400) :
1405 -(leaps_thru_end_of(-(y + 1)) + 1);
1406 }
1407
1408 static struct tm *
timesub(const time_t * timep,long offset,const struct state * sp,struct tm * tmp)1409 timesub(const time_t *timep, long offset, const struct state *sp, struct tm *tmp)
1410 {
1411 const struct lsinfo * lp;
1412 time_t tdays;
1413 int idays; /* unsigned would be so 2003 */
1414 long rem;
1415 int y;
1416 const int * ip;
1417 long corr;
1418 int hit;
1419 int i;
1420 long seconds;
1421
1422 corr = 0;
1423 hit = 0;
1424 i = (sp == NULL) ? 0 : sp->leapcnt;
1425 while (--i >= 0) {
1426 lp = &sp->lsis[i];
1427 if (*timep >= lp->ls_trans) {
1428 if (*timep == lp->ls_trans) {
1429 hit = ((i == 0 && lp->ls_corr > 0) ||
1430 lp->ls_corr > sp->lsis[i - 1].ls_corr);
1431 if (hit) {
1432 while (i > 0 &&
1433 sp->lsis[i].ls_trans ==
1434 sp->lsis[i - 1].ls_trans + 1 &&
1435 sp->lsis[i].ls_corr ==
1436 sp->lsis[i - 1].ls_corr + 1) {
1437 ++hit;
1438 --i;
1439 }
1440 }
1441 }
1442 corr = lp->ls_corr;
1443 break;
1444 }
1445 }
1446 y = EPOCH_YEAR;
1447 tdays = *timep / SECSPERDAY;
1448 rem = *timep - tdays * SECSPERDAY;
1449 while (tdays < 0 || tdays >= year_lengths[isleap(y)]) {
1450 int newy;
1451 time_t tdelta;
1452 int idelta;
1453 int leapdays;
1454
1455 tdelta = tdays / DAYSPERLYEAR;
1456 idelta = tdelta;
1457 if (tdelta - idelta >= 1 || idelta - tdelta >= 1)
1458 return NULL;
1459 if (idelta == 0)
1460 idelta = (tdays < 0) ? -1 : 1;
1461 newy = y;
1462 if (increment_overflow(&newy, idelta))
1463 return NULL;
1464 leapdays = leaps_thru_end_of(newy - 1) -
1465 leaps_thru_end_of(y - 1);
1466 tdays -= ((time_t) newy - y) * DAYSPERNYEAR;
1467 tdays -= leapdays;
1468 y = newy;
1469 }
1470
1471 seconds = tdays * SECSPERDAY + 0.5;
1472 tdays = seconds / SECSPERDAY;
1473 rem += seconds - tdays * SECSPERDAY;
1474
1475 /*
1476 ** Given the range, we can now fearlessly cast...
1477 */
1478 idays = tdays;
1479 rem += offset - corr;
1480 while (rem < 0) {
1481 rem += SECSPERDAY;
1482 --idays;
1483 }
1484 while (rem >= SECSPERDAY) {
1485 rem -= SECSPERDAY;
1486 ++idays;
1487 }
1488 while (idays < 0) {
1489 if (increment_overflow(&y, -1))
1490 return NULL;
1491 idays += year_lengths[isleap(y)];
1492 }
1493 while (idays >= year_lengths[isleap(y)]) {
1494 idays -= year_lengths[isleap(y)];
1495 if (increment_overflow(&y, 1))
1496 return NULL;
1497 }
1498 tmp->tm_year = y;
1499 if (increment_overflow(&tmp->tm_year, -TM_YEAR_BASE))
1500 return NULL;
1501 tmp->tm_yday = idays;
1502 /*
1503 ** The "extra" mods below avoid overflow problems.
1504 */
1505 tmp->tm_wday = EPOCH_WDAY +
1506 ((y - EPOCH_YEAR) % DAYSPERWEEK) *
1507 (DAYSPERNYEAR % DAYSPERWEEK) +
1508 leaps_thru_end_of(y - 1) -
1509 leaps_thru_end_of(EPOCH_YEAR - 1) +
1510 idays;
1511 tmp->tm_wday %= DAYSPERWEEK;
1512 if (tmp->tm_wday < 0)
1513 tmp->tm_wday += DAYSPERWEEK;
1514 tmp->tm_hour = (int) (rem / SECSPERHOUR);
1515 rem %= SECSPERHOUR;
1516 tmp->tm_min = (int) (rem / SECSPERMIN);
1517 /*
1518 ** A positive leap second requires a special
1519 ** representation. This uses "... ??:59:60" et seq.
1520 */
1521 tmp->tm_sec = (int) (rem % SECSPERMIN) + hit;
1522 ip = mon_lengths[isleap(y)];
1523 for (tmp->tm_mon = 0; idays >= ip[tmp->tm_mon]; ++(tmp->tm_mon))
1524 idays -= ip[tmp->tm_mon];
1525 tmp->tm_mday = (int) (idays + 1);
1526 tmp->tm_isdst = 0;
1527 tmp->tm_gmtoff = offset;
1528 return tmp;
1529 }
1530
1531 char *
ctime(const time_t * timep)1532 ctime(const time_t *timep)
1533 {
1534 /*
1535 ** Section 4.12.3.2 of X3.159-1989 requires that
1536 ** The ctime function converts the calendar time pointed to by timer
1537 ** to local time in the form of a string. It is equivalent to
1538 ** asctime(localtime(timer))
1539 */
1540 return asctime(localtime(timep));
1541 }
1542
1543 char *
ctime_r(const time_t * timep,char * buf)1544 ctime_r(const time_t *timep, char *buf)
1545 {
1546 struct tm mytm;
1547
1548 return asctime_r(localtime_r(timep, &mytm), buf);
1549 }
1550
1551 /*
1552 ** Adapted from code provided by Robert Elz, who writes:
1553 ** The "best" way to do mktime I think is based on an idea of Bob
1554 ** Kridle's (so its said...) from a long time ago.
1555 ** It does a binary search of the time_t space. Since time_t's are
1556 ** just 32 bits, its a max of 32 iterations (even at 64 bits it
1557 ** would still be very reasonable).
1558 */
1559
1560 #ifndef WRONG
1561 #define WRONG (-1)
1562 #endif /* !defined WRONG */
1563
1564 /*
1565 ** Normalize logic courtesy Paul Eggert.
1566 */
1567
1568 static int
increment_overflow(int * ip,int j)1569 increment_overflow(int *ip, int j)
1570 {
1571 int const i = *ip;
1572
1573 /*
1574 ** If i >= 0 there can only be overflow if i + j > INT_MAX
1575 ** or if j > INT_MAX - i; given i >= 0, INT_MAX - i cannot overflow.
1576 ** If i < 0 there can only be overflow if i + j < INT_MIN
1577 ** or if j < INT_MIN - i; given i < 0, INT_MIN - i cannot overflow.
1578 */
1579 if ((i >= 0) ? (j > INT_MAX - i) : (j < INT_MIN - i))
1580 return TRUE;
1581 *ip += j;
1582 return FALSE;
1583 }
1584
1585 static int
long_increment_overflow(long * lp,int m)1586 long_increment_overflow(long *lp, int m)
1587 {
1588 long const l = *lp;
1589
1590 if ((l >= 0) ? (m > LONG_MAX - l) : (m < LONG_MIN - l))
1591 return TRUE;
1592 *lp += m;
1593 return FALSE;
1594 }
1595
1596 static int
normalize_overflow(int * tensptr,int * unitsptr,int base)1597 normalize_overflow(int *tensptr, int *unitsptr, int base)
1598 {
1599 int tensdelta;
1600
1601 tensdelta = (*unitsptr >= 0) ?
1602 (*unitsptr / base) :
1603 (-1 - (-1 - *unitsptr) / base);
1604 *unitsptr -= tensdelta * base;
1605 return increment_overflow(tensptr, tensdelta);
1606 }
1607
1608 static int
long_normalize_overflow(long * tensptr,int * unitsptr,int base)1609 long_normalize_overflow(long *tensptr, int *unitsptr, int base)
1610 {
1611 int tensdelta;
1612
1613 tensdelta = (*unitsptr >= 0) ?
1614 (*unitsptr / base) :
1615 (-1 - (-1 - *unitsptr) / base);
1616 *unitsptr -= tensdelta * base;
1617 return long_increment_overflow(tensptr, tensdelta);
1618 }
1619
1620 static int
tmcomp(const struct tm * atmp,const struct tm * btmp)1621 tmcomp(const struct tm *atmp, const struct tm *btmp)
1622 {
1623 int result;
1624
1625 if ((result = (atmp->tm_year - btmp->tm_year)) == 0 &&
1626 (result = (atmp->tm_mon - btmp->tm_mon)) == 0 &&
1627 (result = (atmp->tm_mday - btmp->tm_mday)) == 0 &&
1628 (result = (atmp->tm_hour - btmp->tm_hour)) == 0 &&
1629 (result = (atmp->tm_min - btmp->tm_min)) == 0)
1630 result = atmp->tm_sec - btmp->tm_sec;
1631 return result;
1632 }
1633
1634 static time_t
time2sub(struct tm * tmp,struct tm * (* funcp)(const time_t *,long,struct tm *),long offset,int * okayp,int do_norm_secs)1635 time2sub(struct tm *tmp, struct tm *(*funcp)(const time_t *, long, struct tm *),
1636 long offset, int *okayp, int do_norm_secs)
1637 {
1638 const struct state * sp;
1639 int dir;
1640 int i, j;
1641 int saved_seconds;
1642 long li;
1643 time_t lo;
1644 time_t hi;
1645 long y;
1646 time_t newt;
1647 time_t t;
1648 struct tm yourtm, mytm;
1649
1650 *okayp = FALSE;
1651 yourtm = *tmp;
1652 if (do_norm_secs) {
1653 if (normalize_overflow(&yourtm.tm_min, &yourtm.tm_sec,
1654 SECSPERMIN))
1655 return WRONG;
1656 }
1657 if (normalize_overflow(&yourtm.tm_hour, &yourtm.tm_min, MINSPERHOUR))
1658 return WRONG;
1659 if (normalize_overflow(&yourtm.tm_mday, &yourtm.tm_hour, HOURSPERDAY))
1660 return WRONG;
1661 y = yourtm.tm_year;
1662 if (long_normalize_overflow(&y, &yourtm.tm_mon, MONSPERYEAR))
1663 return WRONG;
1664 /*
1665 ** Turn y into an actual year number for now.
1666 ** It is converted back to an offset from TM_YEAR_BASE later.
1667 */
1668 if (long_increment_overflow(&y, TM_YEAR_BASE))
1669 return WRONG;
1670 while (yourtm.tm_mday <= 0) {
1671 if (long_increment_overflow(&y, -1))
1672 return WRONG;
1673 li = y + (1 < yourtm.tm_mon);
1674 yourtm.tm_mday += year_lengths[isleap(li)];
1675 }
1676 while (yourtm.tm_mday > DAYSPERLYEAR) {
1677 li = y + (1 < yourtm.tm_mon);
1678 yourtm.tm_mday -= year_lengths[isleap(li)];
1679 if (long_increment_overflow(&y, 1))
1680 return WRONG;
1681 }
1682 for ( ; ; ) {
1683 i = mon_lengths[isleap(y)][yourtm.tm_mon];
1684 if (yourtm.tm_mday <= i)
1685 break;
1686 yourtm.tm_mday -= i;
1687 if (++yourtm.tm_mon >= MONSPERYEAR) {
1688 yourtm.tm_mon = 0;
1689 if (long_increment_overflow(&y, 1))
1690 return WRONG;
1691 }
1692 }
1693 if (long_increment_overflow(&y, -TM_YEAR_BASE))
1694 return WRONG;
1695 yourtm.tm_year = y;
1696 if (yourtm.tm_year != y)
1697 return WRONG;
1698 if (yourtm.tm_sec >= 0 && yourtm.tm_sec < SECSPERMIN)
1699 saved_seconds = 0;
1700 else if (y + TM_YEAR_BASE < EPOCH_YEAR) {
1701 /*
1702 ** We can't set tm_sec to 0, because that might push the
1703 ** time below the minimum representable time.
1704 ** Set tm_sec to 59 instead.
1705 ** This assumes that the minimum representable time is
1706 ** not in the same minute that a leap second was deleted from,
1707 ** which is a safer assumption than using 58 would be.
1708 */
1709 if (increment_overflow(&yourtm.tm_sec, 1 - SECSPERMIN))
1710 return WRONG;
1711 saved_seconds = yourtm.tm_sec;
1712 yourtm.tm_sec = SECSPERMIN - 1;
1713 } else {
1714 saved_seconds = yourtm.tm_sec;
1715 yourtm.tm_sec = 0;
1716 }
1717 /*
1718 ** Do a binary search (this works whatever time_t's type is).
1719 */
1720 lo = 1;
1721 for (i = 0; i < (int) TYPE_BIT(time_t) - 1; ++i)
1722 lo *= 2;
1723 hi = -(lo + 1);
1724 for ( ; ; ) {
1725 t = lo / 2 + hi / 2;
1726 if (t < lo)
1727 t = lo;
1728 else if (t > hi)
1729 t = hi;
1730 if ((*funcp)(&t, offset, &mytm) == NULL) {
1731 /*
1732 ** Assume that t is too extreme to be represented in
1733 ** a struct tm; arrange things so that it is less
1734 ** extreme on the next pass.
1735 */
1736 dir = (t > 0) ? 1 : -1;
1737 } else
1738 dir = tmcomp(&mytm, &yourtm);
1739 if (dir != 0) {
1740 if (t == lo) {
1741 ++t;
1742 if (t <= lo)
1743 return WRONG;
1744 ++lo;
1745 } else if (t == hi) {
1746 --t;
1747 if (t >= hi)
1748 return WRONG;
1749 --hi;
1750 }
1751 if (lo > hi)
1752 return WRONG;
1753 if (dir > 0)
1754 hi = t;
1755 else
1756 lo = t;
1757 continue;
1758 }
1759 if (yourtm.tm_isdst < 0 || mytm.tm_isdst == yourtm.tm_isdst)
1760 break;
1761 /*
1762 ** Right time, wrong type.
1763 ** Hunt for right time, right type.
1764 ** It's okay to guess wrong since the guess
1765 ** gets checked.
1766 */
1767 sp = (const struct state *)
1768 ((funcp == localsub) ? lclptr : gmtptr);
1769 if (sp == NULL)
1770 return WRONG;
1771 for (i = sp->typecnt - 1; i >= 0; --i) {
1772 if (sp->ttis[i].tt_isdst != yourtm.tm_isdst)
1773 continue;
1774 for (j = sp->typecnt - 1; j >= 0; --j) {
1775 if (sp->ttis[j].tt_isdst == yourtm.tm_isdst)
1776 continue;
1777 newt = t + sp->ttis[j].tt_gmtoff -
1778 sp->ttis[i].tt_gmtoff;
1779 if ((*funcp)(&newt, offset, &mytm) == NULL)
1780 continue;
1781 if (tmcomp(&mytm, &yourtm) != 0)
1782 continue;
1783 if (mytm.tm_isdst != yourtm.tm_isdst)
1784 continue;
1785 /*
1786 ** We have a match.
1787 */
1788 t = newt;
1789 goto label;
1790 }
1791 }
1792 return WRONG;
1793 }
1794 label:
1795 newt = t + saved_seconds;
1796 if ((newt < t) != (saved_seconds < 0))
1797 return WRONG;
1798 t = newt;
1799 if ((*funcp)(&t, offset, tmp))
1800 *okayp = TRUE;
1801 return t;
1802 }
1803
1804 static time_t
time2(struct tm * tmp,struct tm * (* funcp)(const time_t *,long,struct tm *),long offset,int * okayp)1805 time2(struct tm *tmp, struct tm * (*funcp)(const time_t *, long, struct tm *),
1806 long offset, int *okayp)
1807 {
1808 time_t t;
1809
1810 /*
1811 ** First try without normalization of seconds
1812 ** (in case tm_sec contains a value associated with a leap second).
1813 ** If that fails, try with normalization of seconds.
1814 */
1815 t = time2sub(tmp, funcp, offset, okayp, FALSE);
1816 return *okayp ? t : time2sub(tmp, funcp, offset, okayp, TRUE);
1817 }
1818
1819 static time_t
time1(struct tm * tmp,struct tm * (* funcp)(const time_t *,long,struct tm *),long offset)1820 time1(struct tm *tmp, struct tm * (*funcp)(const time_t *, long, struct tm *),
1821 long offset)
1822 {
1823 time_t t;
1824 const struct state * sp;
1825 int samei, otheri;
1826 int sameind, otherind;
1827 int i;
1828 int nseen;
1829 int seen[TZ_MAX_TYPES];
1830 int types[TZ_MAX_TYPES];
1831 int okay;
1832
1833 if (tmp == NULL) {
1834 errno = EINVAL;
1835 return WRONG;
1836 }
1837 if (tmp->tm_isdst > 1)
1838 tmp->tm_isdst = 1;
1839 t = time2(tmp, funcp, offset, &okay);
1840 #ifdef PCTS
1841 /*
1842 ** PCTS code courtesy Grant Sullivan.
1843 */
1844 if (okay)
1845 return t;
1846 if (tmp->tm_isdst < 0)
1847 tmp->tm_isdst = 0; /* reset to std and try again */
1848 #endif /* defined PCTS */
1849 #ifndef PCTS
1850 if (okay || tmp->tm_isdst < 0)
1851 return t;
1852 #endif /* !defined PCTS */
1853 /*
1854 ** We're supposed to assume that somebody took a time of one type
1855 ** and did some math on it that yielded a "struct tm" that's bad.
1856 ** We try to divine the type they started from and adjust to the
1857 ** type they need.
1858 */
1859 sp = (const struct state *) ((funcp == localsub) ? lclptr : gmtptr);
1860 if (sp == NULL)
1861 return WRONG;
1862 for (i = 0; i < sp->typecnt; ++i)
1863 seen[i] = FALSE;
1864 nseen = 0;
1865 for (i = sp->timecnt - 1; i >= 0; --i) {
1866 if (!seen[sp->types[i]]) {
1867 seen[sp->types[i]] = TRUE;
1868 types[nseen++] = sp->types[i];
1869 }
1870 }
1871 for (sameind = 0; sameind < nseen; ++sameind) {
1872 samei = types[sameind];
1873 if (sp->ttis[samei].tt_isdst != tmp->tm_isdst)
1874 continue;
1875 for (otherind = 0; otherind < nseen; ++otherind) {
1876 otheri = types[otherind];
1877 if (sp->ttis[otheri].tt_isdst == tmp->tm_isdst)
1878 continue;
1879 tmp->tm_sec += sp->ttis[otheri].tt_gmtoff -
1880 sp->ttis[samei].tt_gmtoff;
1881 tmp->tm_isdst = !tmp->tm_isdst;
1882 t = time2(tmp, funcp, offset, &okay);
1883 if (okay)
1884 return t;
1885 tmp->tm_sec -= sp->ttis[otheri].tt_gmtoff -
1886 sp->ttis[samei].tt_gmtoff;
1887 tmp->tm_isdst = !tmp->tm_isdst;
1888 }
1889 }
1890 return WRONG;
1891 }
1892
1893 time_t
mktime(struct tm * tmp)1894 mktime(struct tm *tmp)
1895 {
1896 time_t ret;
1897
1898 _THREAD_PRIVATE_MUTEX_LOCK(lcl);
1899 tzset_basic();
1900 ret = time1(tmp, localsub, 0L);
1901 _THREAD_PRIVATE_MUTEX_UNLOCK(lcl);
1902 return ret;
1903 }
1904 DEF_STRONG(mktime);
1905
1906 #ifdef STD_INSPIRED
1907
1908 time_t
timelocal(struct tm * tmp)1909 timelocal(struct tm *tmp)
1910 {
1911 if (tmp != NULL)
1912 tmp->tm_isdst = -1; /* in case it wasn't initialized */
1913 return mktime(tmp);
1914 }
1915
1916 time_t
timegm(struct tm * tmp)1917 timegm(struct tm *tmp)
1918 {
1919 if (tmp != NULL)
1920 tmp->tm_isdst = 0;
1921 return time1(tmp, gmtsub, 0L);
1922 }
1923
1924 time_t
timeoff(struct tm * tmp,long offset)1925 timeoff(struct tm *tmp, long offset)
1926 {
1927 if (tmp != NULL)
1928 tmp->tm_isdst = 0;
1929 return time1(tmp, gmtsub, offset);
1930 }
1931
1932 #endif /* defined STD_INSPIRED */
1933
1934 /*
1935 ** XXX--is the below the right way to conditionalize??
1936 */
1937
1938 #ifdef STD_INSPIRED
1939
1940 /*
1941 ** IEEE Std 1003.1-1988 (POSIX) legislates that 536457599
1942 ** shall correspond to "Wed Dec 31 23:59:59 UTC 1986", which
1943 ** is not the case if we are accounting for leap seconds.
1944 ** So, we provide the following conversion routines for use
1945 ** when exchanging timestamps with POSIX conforming systems.
1946 */
1947
1948 static long
leapcorr(time_t * timep)1949 leapcorr(time_t *timep)
1950 {
1951 struct state * sp;
1952 struct lsinfo * lp;
1953 int i;
1954
1955 sp = lclptr;
1956 i = sp->leapcnt;
1957 while (--i >= 0) {
1958 lp = &sp->lsis[i];
1959 if (*timep >= lp->ls_trans)
1960 return lp->ls_corr;
1961 }
1962 return 0;
1963 }
1964
1965 time_t
time2posix(time_t t)1966 time2posix(time_t t)
1967 {
1968 tzset();
1969 return t - leapcorr(&t);
1970 }
1971
1972 time_t
posix2time(time_t t)1973 posix2time(time_t t)
1974 {
1975 time_t x;
1976 time_t y;
1977
1978 tzset();
1979 /*
1980 ** For a positive leap second hit, the result
1981 ** is not unique. For a negative leap second
1982 ** hit, the corresponding time doesn't exist,
1983 ** so we return an adjacent second.
1984 */
1985 x = t + leapcorr(&t);
1986 y = x - leapcorr(&x);
1987 if (y < t) {
1988 do {
1989 x++;
1990 y = x - leapcorr(&x);
1991 } while (y < t);
1992 if (t != y)
1993 return x - 1;
1994 } else if (y > t) {
1995 do {
1996 --x;
1997 y = x - leapcorr(&x);
1998 } while (y > t);
1999 if (t != y)
2000 return x + 1;
2001 }
2002 return x;
2003 }
2004
2005 #endif /* defined STD_INSPIRED */
2006