Line data Source code
1 : /* Convert timestamp from pg_time_t to struct pg_tm. */
2 :
3 : /*
4 : * This file is in the public domain, so clarified as of
5 : * 1996-06-05 by Arthur David Olson.
6 : *
7 : * IDENTIFICATION
8 : * src/timezone/localtime.c
9 : */
10 :
11 : /*
12 : * Leap second handling from Bradley White.
13 : * POSIX-style TZ environment variable handling from Guy Harris.
14 : */
15 :
16 : /* this file needs to build in both frontend and backend contexts */
17 : #include "c.h"
18 :
19 : #include <fcntl.h>
20 :
21 : #include "datatype/timestamp.h"
22 : #include "pgtz.h"
23 :
24 : #include "private.h"
25 : #include "tzfile.h"
26 :
27 :
28 : #ifndef WILDABBR
29 : /*
30 : * Someone might make incorrect use of a time zone abbreviation:
31 : * 1. They might reference tzname[0] before calling tzset (explicitly
32 : * or implicitly).
33 : * 2. They might reference tzname[1] before calling tzset (explicitly
34 : * or implicitly).
35 : * 3. They might reference tzname[1] after setting to a time zone
36 : * in which Daylight Saving Time is never observed.
37 : * 4. They might reference tzname[0] after setting to a time zone
38 : * in which Standard Time is never observed.
39 : * 5. They might reference tm.tm_zone after calling offtime.
40 : * What's best to do in the above cases is open to debate;
41 : * for now, we just set things up so that in any of the five cases
42 : * WILDABBR is used. Another possibility: initialize tzname[0] to the
43 : * string "tzname[0] used before set", and similarly for the other cases.
44 : * And another: initialize tzname[0] to "ERA", with an explanation in the
45 : * manual page of what this "time zone abbreviation" means (doing this so
46 : * that tzname[0] has the "normal" length of three characters).
47 : */
48 : #define WILDABBR " "
49 : #endif /* !defined WILDABBR */
50 :
51 : static const char wildabbr[] = WILDABBR;
52 :
53 : static const char gmt[] = "GMT";
54 :
55 : /*
56 : * The DST rules to use if a POSIX TZ string has no rules.
57 : * Default to US rules as of 2017-05-07.
58 : * POSIX does not specify the default DST rules;
59 : * for historical reasons, US rules are a common default.
60 : */
61 : #define TZDEFRULESTRING ",M3.2.0,M11.1.0"
62 :
63 : /* structs ttinfo, lsinfo, state have been moved to pgtz.h */
64 :
65 : enum r_type
66 : {
67 : JULIAN_DAY, /* Jn = Julian day */
68 : DAY_OF_YEAR, /* n = day of year */
69 : MONTH_NTH_DAY_OF_WEEK /* Mm.n.d = month, week, day of week */
70 : };
71 :
72 : struct rule
73 : {
74 : enum r_type r_type; /* type of rule */
75 : int r_day; /* day number of rule */
76 : int r_week; /* week number of rule */
77 : int r_mon; /* month number of rule */
78 : int_fast32_t r_time; /* transition time of rule */
79 : };
80 :
81 : /*
82 : * Prototypes for static functions.
83 : */
84 :
85 : static struct pg_tm *gmtsub(pg_time_t const *timep, int_fast32_t offset,
86 : struct pg_tm *tmp);
87 : static bool increment_overflow(int *ip, int j);
88 : static bool increment_overflow_time(pg_time_t *tp, int_fast32_t j);
89 : static int_fast64_t leapcorr(struct state const *sp, pg_time_t);
90 : static struct pg_tm *timesub(pg_time_t const *timep,
91 : int_fast32_t offset, struct state const *sp,
92 : struct pg_tm *tmp);
93 : static bool typesequiv(struct state const *sp, int a, int b);
94 :
95 :
96 : /*
97 : * Section 4.12.3 of X3.159-1989 requires that
98 : * Except for the strftime function, these functions [asctime,
99 : * ctime, gmtime, localtime] return values in one of two static
100 : * objects: a broken-down time structure and an array of char.
101 : * Thanks to Paul Eggert for noting this.
102 : */
103 :
104 : static struct pg_tm tm;
105 :
106 : /* Initialize *S to a value based on UTOFF, ISDST, and DESIGIDX. */
107 : static void
108 104 : init_ttinfo(struct ttinfo *s, int_fast32_t utoff, bool isdst, int desigidx)
109 : {
110 104 : s->tt_utoff = utoff;
111 104 : s->tt_isdst = isdst;
112 104 : s->tt_desigidx = desigidx;
113 104 : s->tt_ttisstd = false;
114 104 : s->tt_ttisut = false;
115 104 : }
116 :
117 : static int_fast32_t
118 1456 : detzcode(const char *const codep)
119 : {
120 : int_fast32_t result;
121 : int i;
122 1456 : int_fast32_t one = 1;
123 1456 : int_fast32_t halfmaxval = one << (32 - 2);
124 1456 : int_fast32_t maxval = halfmaxval - 1 + halfmaxval;
125 1456 : int_fast32_t minval = -1 - maxval;
126 :
127 1456 : result = codep[0] & 0x7f;
128 5824 : for (i = 1; i < 4; ++i)
129 4368 : result = (result << 8) | (codep[i] & 0xff);
130 :
131 1456 : if (codep[0] & 0x80)
132 : {
133 : /*
134 : * Do two's-complement negation even on non-two's-complement machines.
135 : * If the result would be minval - 1, return minval.
136 : */
137 0 : result -= !TWOS_COMPLEMENT(int_fast32_t) && result != 0;
138 0 : result += minval;
139 : }
140 1456 : return result;
141 : }
142 :
143 : static int_fast64_t
144 0 : detzcode64(const char *const codep)
145 : {
146 : uint_fast64_t result;
147 : int i;
148 0 : int_fast64_t one = 1;
149 0 : int_fast64_t halfmaxval = one << (64 - 2);
150 0 : int_fast64_t maxval = halfmaxval - 1 + halfmaxval;
151 0 : int_fast64_t minval = -TWOS_COMPLEMENT(int_fast64_t) - maxval;
152 :
153 0 : result = codep[0] & 0x7f;
154 0 : for (i = 1; i < 8; ++i)
155 0 : result = (result << 8) | (codep[i] & 0xff);
156 :
157 0 : if (codep[0] & 0x80)
158 : {
159 : /*
160 : * Do two's-complement negation even on non-two's-complement machines.
161 : * If the result would be minval - 1, return minval.
162 : */
163 0 : result -= !TWOS_COMPLEMENT(int_fast64_t) && result != 0;
164 0 : result += minval;
165 : }
166 0 : return result;
167 : }
168 :
169 : static bool
170 0 : differ_by_repeat(const pg_time_t t1, const pg_time_t t0)
171 : {
172 : if (TYPE_BIT(pg_time_t) - TYPE_SIGNED(pg_time_t) < SECSPERREPEAT_BITS)
173 : return 0;
174 0 : return t1 - t0 == SECSPERREPEAT;
175 : }
176 :
177 : /* Input buffer for data read from a compiled tz file. */
178 : union input_buffer
179 : {
180 : /* The first part of the buffer, interpreted as a header. */
181 : struct tzhead tzhead;
182 :
183 : /* The entire buffer. */
184 : char buf[2 * sizeof(struct tzhead) + 2 * sizeof(struct state)
185 : + 4 * TZ_MAX_TIMES];
186 : };
187 :
188 : /* Local storage needed for 'tzloadbody'. */
189 : union local_storage
190 : {
191 : /* The results of analyzing the file's contents after it is opened. */
192 : struct file_analysis
193 : {
194 : /* The input buffer. */
195 : union input_buffer u;
196 :
197 : /* A temporary state used for parsing a TZ string in the file. */
198 : struct state st;
199 : } u;
200 :
201 : /* We don't need the "fullname" member */
202 : };
203 :
204 : /* Load tz data from the file named NAME into *SP. Read extended
205 : * format if DOEXTEND. Use *LSP for temporary storage. Return 0 on
206 : * success, an errno value on failure.
207 : * PG: If "canonname" is not NULL, then on success the canonical spelling of
208 : * given name is stored there (the buffer must be > TZ_STRLEN_MAX bytes!).
209 : */
210 : static int
211 208 : tzloadbody(char const *name, char *canonname, struct state *sp, bool doextend,
212 : union local_storage *lsp)
213 : {
214 : int i;
215 : int fid;
216 : int stored;
217 : ssize_t nread;
218 208 : union input_buffer *up = &lsp->u.u;
219 208 : int tzheadsize = sizeof(struct tzhead);
220 :
221 208 : sp->goback = sp->goahead = false;
222 :
223 208 : if (!name)
224 : {
225 0 : name = TZDEFAULT;
226 0 : if (!name)
227 0 : return EINVAL;
228 : }
229 :
230 208 : if (name[0] == ':')
231 0 : ++name;
232 :
233 208 : fid = pg_open_tzfile(name, canonname);
234 208 : if (fid < 0)
235 104 : return ENOENT; /* pg_open_tzfile may not set errno */
236 :
237 104 : nread = read(fid, up->buf, sizeof up->buf);
238 104 : if (nread < tzheadsize)
239 : {
240 0 : int err = nread < 0 ? errno : EINVAL;
241 :
242 0 : close(fid);
243 0 : return err;
244 : }
245 104 : if (close(fid) < 0)
246 0 : return errno;
247 312 : for (stored = 4; stored <= 8; stored *= 2)
248 : {
249 208 : int_fast32_t ttisstdcnt = detzcode(up->tzhead.tzh_ttisstdcnt);
250 208 : int_fast32_t ttisutcnt = detzcode(up->tzhead.tzh_ttisutcnt);
251 208 : int_fast64_t prevtr = 0;
252 208 : int_fast32_t prevcorr = 0;
253 208 : int_fast32_t leapcnt = detzcode(up->tzhead.tzh_leapcnt);
254 208 : int_fast32_t timecnt = detzcode(up->tzhead.tzh_timecnt);
255 208 : int_fast32_t typecnt = detzcode(up->tzhead.tzh_typecnt);
256 208 : int_fast32_t charcnt = detzcode(up->tzhead.tzh_charcnt);
257 208 : char const *p = up->buf + tzheadsize;
258 :
259 : /*
260 : * Although tzfile(5) currently requires typecnt to be nonzero,
261 : * support future formats that may allow zero typecnt in files that
262 : * have a TZ string and no transitions.
263 : */
264 416 : if (!(0 <= leapcnt && leapcnt < TZ_MAX_LEAPS
265 208 : && 0 <= typecnt && typecnt < TZ_MAX_TYPES
266 208 : && 0 <= timecnt && timecnt < TZ_MAX_TIMES
267 208 : && 0 <= charcnt && charcnt < TZ_MAX_CHARS
268 208 : && (ttisstdcnt == typecnt || ttisstdcnt == 0)
269 208 : && (ttisutcnt == typecnt || ttisutcnt == 0)))
270 0 : return EINVAL;
271 208 : if (nread
272 : < (tzheadsize /* struct tzhead */
273 208 : + timecnt * stored /* ats */
274 208 : + timecnt /* types */
275 208 : + typecnt * 6 /* ttinfos */
276 208 : + charcnt /* chars */
277 208 : + leapcnt * (stored + 4) /* lsinfos */
278 208 : + ttisstdcnt /* ttisstds */
279 208 : + ttisutcnt)) /* ttisuts */
280 0 : return EINVAL;
281 208 : sp->leapcnt = leapcnt;
282 208 : sp->timecnt = timecnt;
283 208 : sp->typecnt = typecnt;
284 208 : sp->charcnt = charcnt;
285 :
286 : /*
287 : * Read transitions, discarding those out of pg_time_t range. But
288 : * pretend the last transition before TIME_T_MIN occurred at
289 : * TIME_T_MIN.
290 : */
291 208 : timecnt = 0;
292 208 : for (i = 0; i < sp->timecnt; ++i)
293 : {
294 0 : int_fast64_t at
295 0 : = stored == 4 ? detzcode(p) : detzcode64(p);
296 :
297 0 : sp->types[i] = at <= TIME_T_MAX;
298 0 : if (sp->types[i])
299 : {
300 0 : pg_time_t attime
301 : = ((TYPE_SIGNED(pg_time_t) ? at < TIME_T_MIN : at < 0)
302 : ? TIME_T_MIN : at);
303 :
304 0 : if (timecnt && attime <= sp->ats[timecnt - 1])
305 : {
306 0 : if (attime < sp->ats[timecnt - 1])
307 0 : return EINVAL;
308 0 : sp->types[i - 1] = 0;
309 0 : timecnt--;
310 : }
311 0 : sp->ats[timecnt++] = attime;
312 : }
313 0 : p += stored;
314 : }
315 :
316 208 : timecnt = 0;
317 208 : for (i = 0; i < sp->timecnt; ++i)
318 : {
319 0 : unsigned char typ = *p++;
320 :
321 0 : if (sp->typecnt <= typ)
322 0 : return EINVAL;
323 0 : if (sp->types[i])
324 0 : sp->types[timecnt++] = typ;
325 : }
326 208 : sp->timecnt = timecnt;
327 416 : for (i = 0; i < sp->typecnt; ++i)
328 : {
329 : struct ttinfo *ttisp;
330 : unsigned char isdst,
331 : desigidx;
332 :
333 208 : ttisp = &sp->ttis[i];
334 208 : ttisp->tt_utoff = detzcode(p);
335 208 : p += 4;
336 208 : isdst = *p++;
337 208 : if (!(isdst < 2))
338 0 : return EINVAL;
339 208 : ttisp->tt_isdst = isdst;
340 208 : desigidx = *p++;
341 208 : if (!(desigidx < sp->charcnt))
342 0 : return EINVAL;
343 208 : ttisp->tt_desigidx = desigidx;
344 : }
345 728 : for (i = 0; i < sp->charcnt; ++i)
346 520 : sp->chars[i] = *p++;
347 208 : sp->chars[i] = '\0'; /* ensure '\0' at end */
348 :
349 : /* Read leap seconds, discarding those out of pg_time_t range. */
350 208 : leapcnt = 0;
351 208 : for (i = 0; i < sp->leapcnt; ++i)
352 : {
353 0 : int_fast64_t tr = stored == 4 ? detzcode(p) : detzcode64(p);
354 0 : int_fast32_t corr = detzcode(p + stored);
355 :
356 0 : p += stored + 4;
357 : /* Leap seconds cannot occur before the Epoch. */
358 0 : if (tr < 0)
359 0 : return EINVAL;
360 : if (tr <= TIME_T_MAX)
361 : {
362 : /*
363 : * Leap seconds cannot occur more than once per UTC month, and
364 : * UTC months are at least 28 days long (minus 1 second for a
365 : * negative leap second). Each leap second's correction must
366 : * differ from the previous one's by 1 second.
367 : */
368 0 : if (tr - prevtr < 28 * SECSPERDAY - 1
369 0 : || (corr != prevcorr - 1 && corr != prevcorr + 1))
370 0 : return EINVAL;
371 0 : sp->lsis[leapcnt].ls_trans = prevtr = tr;
372 0 : sp->lsis[leapcnt].ls_corr = prevcorr = corr;
373 0 : leapcnt++;
374 : }
375 : }
376 208 : sp->leapcnt = leapcnt;
377 :
378 416 : for (i = 0; i < sp->typecnt; ++i)
379 : {
380 : struct ttinfo *ttisp;
381 :
382 208 : ttisp = &sp->ttis[i];
383 208 : if (ttisstdcnt == 0)
384 208 : ttisp->tt_ttisstd = false;
385 : else
386 : {
387 0 : if (*p != true && *p != false)
388 0 : return EINVAL;
389 0 : ttisp->tt_ttisstd = *p++;
390 : }
391 : }
392 416 : for (i = 0; i < sp->typecnt; ++i)
393 : {
394 : struct ttinfo *ttisp;
395 :
396 208 : ttisp = &sp->ttis[i];
397 208 : if (ttisutcnt == 0)
398 208 : ttisp->tt_ttisut = false;
399 : else
400 : {
401 0 : if (*p != true && *p != false)
402 0 : return EINVAL;
403 0 : ttisp->tt_ttisut = *p++;
404 : }
405 : }
406 :
407 : /*
408 : * If this is an old file, we're done.
409 : */
410 208 : if (up->tzhead.tzh_version[0] == '\0')
411 0 : break;
412 208 : nread -= p - up->buf;
413 208 : memmove(up->buf, p, nread);
414 : }
415 104 : if (doextend && nread > 2 &&
416 104 : up->buf[0] == '\n' && up->buf[nread - 1] == '\n' &&
417 104 : sp->typecnt + 2 <= TZ_MAX_TYPES)
418 : {
419 104 : struct state *ts = &lsp->u.st;
420 :
421 104 : up->buf[nread - 1] = '\0';
422 104 : if (tzparse(&up->buf[1], ts, false))
423 : {
424 :
425 : /*
426 : * Attempt to reuse existing abbreviations. Without this,
427 : * America/Anchorage would be right on the edge after 2037 when
428 : * TZ_MAX_CHARS is 50, as sp->charcnt equals 40 (for LMT AST AWT
429 : * APT AHST AHDT YST AKDT AKST) and ts->charcnt equals 10 (for
430 : * AKST AKDT). Reusing means sp->charcnt can stay 40 in this
431 : * example.
432 : */
433 104 : int gotabbr = 0;
434 104 : int charcnt = sp->charcnt;
435 :
436 208 : for (i = 0; i < ts->typecnt; i++)
437 : {
438 104 : char *tsabbr = ts->chars + ts->ttis[i].tt_desigidx;
439 : int j;
440 :
441 104 : for (j = 0; j < charcnt; j++)
442 104 : if (strcmp(sp->chars + j, tsabbr) == 0)
443 : {
444 104 : ts->ttis[i].tt_desigidx = j;
445 104 : gotabbr++;
446 104 : break;
447 : }
448 104 : if (!(j < charcnt))
449 : {
450 0 : int tsabbrlen = strlen(tsabbr);
451 :
452 0 : if (j + tsabbrlen < TZ_MAX_CHARS)
453 : {
454 0 : strcpy(sp->chars + j, tsabbr);
455 0 : charcnt = j + tsabbrlen + 1;
456 0 : ts->ttis[i].tt_desigidx = j;
457 0 : gotabbr++;
458 : }
459 : }
460 : }
461 104 : if (gotabbr == ts->typecnt)
462 : {
463 104 : sp->charcnt = charcnt;
464 :
465 : /*
466 : * Ignore any trailing, no-op transitions generated by zic as
467 : * they don't help here and can run afoul of bugs in zic 2016j
468 : * or earlier.
469 : */
470 104 : while (1 < sp->timecnt
471 104 : && (sp->types[sp->timecnt - 1]
472 0 : == sp->types[sp->timecnt - 2]))
473 0 : sp->timecnt--;
474 :
475 104 : for (i = 0; i < ts->timecnt; i++)
476 0 : if (sp->timecnt == 0
477 0 : || (sp->ats[sp->timecnt - 1]
478 0 : < ts->ats[i] + leapcorr(sp, ts->ats[i])))
479 : break;
480 104 : while (i < ts->timecnt
481 104 : && sp->timecnt < TZ_MAX_TIMES)
482 : {
483 0 : sp->ats[sp->timecnt]
484 0 : = ts->ats[i] + leapcorr(sp, ts->ats[i]);
485 0 : sp->types[sp->timecnt] = (sp->typecnt
486 0 : + ts->types[i]);
487 0 : sp->timecnt++;
488 0 : i++;
489 : }
490 208 : for (i = 0; i < ts->typecnt; i++)
491 104 : sp->ttis[sp->typecnt++] = ts->ttis[i];
492 : }
493 : }
494 : }
495 104 : if (sp->typecnt == 0)
496 0 : return EINVAL;
497 104 : if (sp->timecnt > 1)
498 : {
499 0 : for (i = 1; i < sp->timecnt; ++i)
500 0 : if (typesequiv(sp, sp->types[i], sp->types[0]) &&
501 0 : differ_by_repeat(sp->ats[i], sp->ats[0]))
502 : {
503 0 : sp->goback = true;
504 0 : break;
505 : }
506 0 : for (i = sp->timecnt - 2; i >= 0; --i)
507 0 : if (typesequiv(sp, sp->types[sp->timecnt - 1],
508 0 : sp->types[i]) &&
509 0 : differ_by_repeat(sp->ats[sp->timecnt - 1],
510 : sp->ats[i]))
511 : {
512 0 : sp->goahead = true;
513 0 : break;
514 : }
515 : }
516 :
517 : /*
518 : * Infer sp->defaulttype from the data. Although this default type is
519 : * always zero for data from recent tzdb releases, things are trickier for
520 : * data from tzdb 2018e or earlier.
521 : *
522 : * The first set of heuristics work around bugs in 32-bit data generated
523 : * by tzdb 2013c or earlier. The workaround is for zones like
524 : * Australia/Macquarie where timestamps before the first transition have a
525 : * time type that is not the earliest standard-time type. See:
526 : * https://mm.icann.org/pipermail/tz/2013-May/019368.html
527 : */
528 :
529 : /*
530 : * If type 0 is unused in transitions, it's the type to use for early
531 : * times.
532 : */
533 104 : for (i = 0; i < sp->timecnt; ++i)
534 0 : if (sp->types[i] == 0)
535 0 : break;
536 104 : i = i < sp->timecnt ? -1 : 0;
537 :
538 : /*
539 : * Absent the above, if there are transition times and the first
540 : * transition is to a daylight time find the standard type less than and
541 : * closest to the type of the first transition.
542 : */
543 104 : if (i < 0 && sp->timecnt > 0 && sp->ttis[sp->types[0]].tt_isdst)
544 : {
545 0 : i = sp->types[0];
546 0 : while (--i >= 0)
547 0 : if (!sp->ttis[i].tt_isdst)
548 0 : break;
549 : }
550 :
551 : /*
552 : * The next heuristics are for data generated by tzdb 2018e or earlier,
553 : * for zones like EST5EDT where the first transition is to DST.
554 : */
555 :
556 : /*
557 : * If no result yet, find the first standard type. If there is none, punt
558 : * to type zero.
559 : */
560 104 : if (i < 0)
561 : {
562 0 : i = 0;
563 0 : while (sp->ttis[i].tt_isdst)
564 0 : if (++i >= sp->typecnt)
565 : {
566 0 : i = 0;
567 0 : break;
568 : }
569 : }
570 :
571 : /*
572 : * A simple 'sp->defaulttype = 0;' would suffice here if we didn't have to
573 : * worry about 2018e-or-earlier data. Even simpler would be to remove the
574 : * defaulttype member and just use 0 in its place.
575 : */
576 104 : sp->defaulttype = i;
577 :
578 104 : return 0;
579 : }
580 :
581 : /* Load tz data from the file named NAME into *SP. Read extended
582 : * format if DOEXTEND. Return 0 on success, an errno value on failure.
583 : * PG: If "canonname" is not NULL, then on success the canonical spelling of
584 : * given name is stored there (the buffer must be > TZ_STRLEN_MAX bytes!).
585 : */
586 : int
587 208 : tzload(char const *name, char *canonname, struct state *sp, bool doextend)
588 : {
589 208 : union local_storage *lsp = malloc(sizeof *lsp);
590 :
591 208 : if (!lsp)
592 0 : return errno;
593 : else
594 : {
595 208 : int err = tzloadbody(name, canonname, sp, doextend, lsp);
596 :
597 208 : free(lsp);
598 208 : return err;
599 : }
600 : }
601 :
602 : static bool
603 0 : typesequiv(const struct state *sp, int a, int b)
604 : {
605 : bool result;
606 :
607 0 : if (sp == NULL ||
608 0 : a < 0 || a >= sp->typecnt ||
609 0 : b < 0 || b >= sp->typecnt)
610 0 : result = false;
611 : else
612 : {
613 0 : const struct ttinfo *ap = &sp->ttis[a];
614 0 : const struct ttinfo *bp = &sp->ttis[b];
615 :
616 0 : result = (ap->tt_utoff == bp->tt_utoff
617 0 : && ap->tt_isdst == bp->tt_isdst
618 0 : && ap->tt_ttisstd == bp->tt_ttisstd
619 0 : && ap->tt_ttisut == bp->tt_ttisut
620 0 : && (strcmp(&sp->chars[ap->tt_desigidx],
621 0 : &sp->chars[bp->tt_desigidx])
622 : == 0));
623 : }
624 0 : return result;
625 : }
626 :
627 : static const int mon_lengths[2][MONSPERYEAR] = {
628 : {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
629 : {31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}
630 : };
631 :
632 : static const int year_lengths[2] = {
633 : DAYSPERNYEAR, DAYSPERLYEAR
634 : };
635 :
636 : /*
637 : * Given a pointer into a timezone string, scan until a character that is not
638 : * a valid character in a time zone abbreviation is found.
639 : * Return a pointer to that character.
640 : */
641 :
642 : static const char *
643 208 : getzname(const char *strp)
644 : {
645 : char c;
646 :
647 2496 : while ((c = *strp) != '\0' && !is_digit(c) && c != ',' && c != '-' &&
648 : c != '+')
649 2288 : ++strp;
650 208 : return strp;
651 : }
652 :
653 : /*
654 : * Given a pointer into an extended timezone string, scan until the ending
655 : * delimiter of the time zone abbreviation is located.
656 : * Return a pointer to the delimiter.
657 : *
658 : * As with getzname above, the legal character set is actually quite
659 : * restricted, with other characters producing undefined results.
660 : * We don't do any checking here; checking is done later in common-case code.
661 : */
662 :
663 : static const char *
664 0 : getqzname(const char *strp, const int delim)
665 : {
666 : int c;
667 :
668 0 : while ((c = *strp) != '\0' && c != delim)
669 0 : ++strp;
670 0 : return strp;
671 : }
672 :
673 : /*
674 : * Given a pointer into a timezone string, extract a number from that string.
675 : * Check that the number is within a specified range; if it is not, return
676 : * NULL.
677 : * Otherwise, return a pointer to the first character not part of the number.
678 : */
679 :
680 : static const char *
681 104 : getnum(const char *strp, int *const nump, const int min, const int max)
682 : {
683 : char c;
684 : int num;
685 :
686 104 : if (strp == NULL || !is_digit(c = *strp))
687 0 : return NULL;
688 104 : num = 0;
689 : do
690 : {
691 104 : num = num * 10 + (c - '0');
692 104 : if (num > max)
693 0 : return NULL; /* illegal value */
694 104 : c = *++strp;
695 104 : } while (is_digit(c));
696 104 : if (num < min)
697 0 : return NULL; /* illegal value */
698 104 : *nump = num;
699 104 : return strp;
700 : }
701 :
702 : /*
703 : * Given a pointer into a timezone string, extract a number of seconds,
704 : * in hh[:mm[:ss]] form, from the string.
705 : * If any error occurs, return NULL.
706 : * Otherwise, return a pointer to the first character not part of the number
707 : * of seconds.
708 : */
709 :
710 : static const char *
711 104 : getsecs(const char *strp, int_fast32_t *const secsp)
712 : {
713 : int num;
714 :
715 : /*
716 : * 'HOURSPERDAY * DAYSPERWEEK - 1' allows quasi-Posix rules like
717 : * "M10.4.6/26", which does not conform to Posix, but which specifies the
718 : * equivalent of "02:00 on the first Sunday on or after 23 Oct".
719 : */
720 104 : strp = getnum(strp, &num, 0, HOURSPERDAY * DAYSPERWEEK - 1);
721 104 : if (strp == NULL)
722 0 : return NULL;
723 104 : *secsp = num * (int_fast32_t) SECSPERHOUR;
724 104 : if (*strp == ':')
725 : {
726 0 : ++strp;
727 0 : strp = getnum(strp, &num, 0, MINSPERHOUR - 1);
728 0 : if (strp == NULL)
729 0 : return NULL;
730 0 : *secsp += num * SECSPERMIN;
731 0 : if (*strp == ':')
732 : {
733 0 : ++strp;
734 : /* 'SECSPERMIN' allows for leap seconds. */
735 0 : strp = getnum(strp, &num, 0, SECSPERMIN);
736 0 : if (strp == NULL)
737 0 : return NULL;
738 0 : *secsp += num;
739 : }
740 : }
741 104 : return strp;
742 : }
743 :
744 : /*
745 : * Given a pointer into a timezone string, extract an offset, in
746 : * [+-]hh[:mm[:ss]] form, from the string.
747 : * If any error occurs, return NULL.
748 : * Otherwise, return a pointer to the first character not part of the time.
749 : */
750 :
751 : static const char *
752 104 : getoffset(const char *strp, int_fast32_t *const offsetp)
753 : {
754 104 : bool neg = false;
755 :
756 104 : if (*strp == '-')
757 : {
758 0 : neg = true;
759 0 : ++strp;
760 : }
761 104 : else if (*strp == '+')
762 0 : ++strp;
763 104 : strp = getsecs(strp, offsetp);
764 104 : if (strp == NULL)
765 0 : return NULL; /* illegal time */
766 104 : if (neg)
767 0 : *offsetp = -*offsetp;
768 104 : return strp;
769 : }
770 :
771 : /*
772 : * Given a pointer into a timezone string, extract a rule in the form
773 : * date[/time]. See POSIX section 8 for the format of "date" and "time".
774 : * If a valid rule is not found, return NULL.
775 : * Otherwise, return a pointer to the first character not part of the rule.
776 : */
777 :
778 : static const char *
779 0 : getrule(const char *strp, struct rule *const rulep)
780 : {
781 0 : if (*strp == 'J')
782 : {
783 : /*
784 : * Julian day.
785 : */
786 0 : rulep->r_type = JULIAN_DAY;
787 0 : ++strp;
788 0 : strp = getnum(strp, &rulep->r_day, 1, DAYSPERNYEAR);
789 : }
790 0 : else if (*strp == 'M')
791 : {
792 : /*
793 : * Month, week, day.
794 : */
795 0 : rulep->r_type = MONTH_NTH_DAY_OF_WEEK;
796 0 : ++strp;
797 0 : strp = getnum(strp, &rulep->r_mon, 1, MONSPERYEAR);
798 0 : if (strp == NULL)
799 0 : return NULL;
800 0 : if (*strp++ != '.')
801 0 : return NULL;
802 0 : strp = getnum(strp, &rulep->r_week, 1, 5);
803 0 : if (strp == NULL)
804 0 : return NULL;
805 0 : if (*strp++ != '.')
806 0 : return NULL;
807 0 : strp = getnum(strp, &rulep->r_day, 0, DAYSPERWEEK - 1);
808 : }
809 0 : else if (is_digit(*strp))
810 : {
811 : /*
812 : * Day of year.
813 : */
814 0 : rulep->r_type = DAY_OF_YEAR;
815 0 : strp = getnum(strp, &rulep->r_day, 0, DAYSPERLYEAR - 1);
816 : }
817 : else
818 0 : return NULL; /* invalid format */
819 0 : if (strp == NULL)
820 0 : return NULL;
821 0 : if (*strp == '/')
822 : {
823 : /*
824 : * Time specified.
825 : */
826 0 : ++strp;
827 0 : strp = getoffset(strp, &rulep->r_time);
828 : }
829 : else
830 0 : rulep->r_time = 2 * SECSPERHOUR; /* default = 2:00:00 */
831 0 : return strp;
832 : }
833 :
834 : /*
835 : * Given a year, a rule, and the offset from UT at the time that rule takes
836 : * effect, calculate the year-relative time that rule takes effect.
837 : */
838 :
839 : static int_fast32_t
840 0 : transtime(const int year, const struct rule *const rulep,
841 : const int_fast32_t offset)
842 : {
843 : bool leapyear;
844 : int_fast32_t value;
845 : int i;
846 : int d,
847 : m1,
848 : yy0,
849 : yy1,
850 : yy2,
851 : dow;
852 :
853 0 : INITIALIZE(value);
854 0 : leapyear = isleap(year);
855 0 : switch (rulep->r_type)
856 : {
857 :
858 0 : case JULIAN_DAY:
859 :
860 : /*
861 : * Jn - Julian day, 1 == January 1, 60 == March 1 even in leap
862 : * years. In non-leap years, or if the day number is 59 or less,
863 : * just add SECSPERDAY times the day number-1 to the time of
864 : * January 1, midnight, to get the day.
865 : */
866 0 : value = (rulep->r_day - 1) * SECSPERDAY;
867 0 : if (leapyear && rulep->r_day >= 60)
868 0 : value += SECSPERDAY;
869 0 : break;
870 :
871 0 : case DAY_OF_YEAR:
872 :
873 : /*
874 : * n - day of year. Just add SECSPERDAY times the day number to
875 : * the time of January 1, midnight, to get the day.
876 : */
877 0 : value = rulep->r_day * SECSPERDAY;
878 0 : break;
879 :
880 0 : case MONTH_NTH_DAY_OF_WEEK:
881 :
882 : /*
883 : * Mm.n.d - nth "dth day" of month m.
884 : */
885 :
886 : /*
887 : * Use Zeller's Congruence to get day-of-week of first day of
888 : * month.
889 : */
890 0 : m1 = (rulep->r_mon + 9) % 12 + 1;
891 0 : yy0 = (rulep->r_mon <= 2) ? (year - 1) : year;
892 0 : yy1 = yy0 / 100;
893 0 : yy2 = yy0 % 100;
894 0 : dow = ((26 * m1 - 2) / 10 +
895 0 : 1 + yy2 + yy2 / 4 + yy1 / 4 - 2 * yy1) % 7;
896 0 : if (dow < 0)
897 0 : dow += DAYSPERWEEK;
898 :
899 : /*
900 : * "dow" is the day-of-week of the first day of the month. Get the
901 : * day-of-month (zero-origin) of the first "dow" day of the month.
902 : */
903 0 : d = rulep->r_day - dow;
904 0 : if (d < 0)
905 0 : d += DAYSPERWEEK;
906 0 : for (i = 1; i < rulep->r_week; ++i)
907 : {
908 0 : if (d + DAYSPERWEEK >=
909 0 : mon_lengths[leapyear][rulep->r_mon - 1])
910 0 : break;
911 0 : d += DAYSPERWEEK;
912 : }
913 :
914 : /*
915 : * "d" is the day-of-month (zero-origin) of the day we want.
916 : */
917 0 : value = d * SECSPERDAY;
918 0 : for (i = 0; i < rulep->r_mon - 1; ++i)
919 0 : value += mon_lengths[leapyear][i] * SECSPERDAY;
920 0 : break;
921 : }
922 :
923 : /*
924 : * "value" is the year-relative time of 00:00:00 UT on the day in
925 : * question. To get the year-relative time of the specified local time on
926 : * that day, add the transition time and the current offset from UT.
927 : */
928 0 : return value + rulep->r_time + offset;
929 : }
930 :
931 : /*
932 : * Given a POSIX section 8-style TZ string, fill in the rule tables as
933 : * appropriate.
934 : * Returns true on success, false on failure.
935 : */
936 : bool
937 208 : tzparse(const char *name, struct state *sp, bool lastditch)
938 : {
939 : const char *stdname;
940 208 : const char *dstname = NULL;
941 : size_t stdlen;
942 : size_t dstlen;
943 : size_t charcnt;
944 : int_fast32_t stdoffset;
945 : int_fast32_t dstoffset;
946 : char *cp;
947 : bool load_ok;
948 :
949 208 : stdname = name;
950 208 : if (lastditch)
951 : {
952 : /* Unlike IANA, don't assume name is exactly "GMT" */
953 0 : stdlen = strlen(name); /* length of standard zone name */
954 0 : name += stdlen;
955 0 : stdoffset = 0;
956 : }
957 : else
958 : {
959 208 : if (*name == '<')
960 : {
961 0 : name++;
962 0 : stdname = name;
963 0 : name = getqzname(name, '>');
964 0 : if (*name != '>')
965 0 : return false;
966 0 : stdlen = name - stdname;
967 0 : name++;
968 : }
969 : else
970 : {
971 208 : name = getzname(name);
972 208 : stdlen = name - stdname;
973 : }
974 208 : if (*name == '\0') /* we allow empty STD abbrev, unlike IANA */
975 104 : return false;
976 104 : name = getoffset(name, &stdoffset);
977 104 : if (name == NULL)
978 0 : return false;
979 : }
980 104 : charcnt = stdlen + 1;
981 104 : if (sizeof sp->chars < charcnt)
982 0 : return false;
983 :
984 : /*
985 : * The IANA code always tries to tzload(TZDEFRULES) here. We do not want
986 : * to do that; it would be bad news in the lastditch case, where we can't
987 : * assume pg_open_tzfile() is sane yet. Moreover, if we did load it and
988 : * it contains leap-second-dependent info, that would cause problems too.
989 : * Finally, IANA has deprecated the TZDEFRULES feature, so it presumably
990 : * will die at some point. Desupporting it now seems like good
991 : * future-proofing.
992 : */
993 104 : load_ok = false;
994 104 : sp->goback = sp->goahead = false; /* simulate failed tzload() */
995 104 : sp->leapcnt = 0; /* intentionally assume no leap seconds */
996 :
997 104 : if (*name != '\0')
998 : {
999 0 : if (*name == '<')
1000 : {
1001 0 : dstname = ++name;
1002 0 : name = getqzname(name, '>');
1003 0 : if (*name != '>')
1004 0 : return false;
1005 0 : dstlen = name - dstname;
1006 0 : name++;
1007 : }
1008 : else
1009 : {
1010 0 : dstname = name;
1011 0 : name = getzname(name);
1012 0 : dstlen = name - dstname; /* length of DST abbr. */
1013 : }
1014 0 : if (!dstlen)
1015 0 : return false;
1016 0 : charcnt += dstlen + 1;
1017 0 : if (sizeof sp->chars < charcnt)
1018 0 : return false;
1019 0 : if (*name != '\0' && *name != ',' && *name != ';')
1020 : {
1021 0 : name = getoffset(name, &dstoffset);
1022 0 : if (name == NULL)
1023 0 : return false;
1024 : }
1025 : else
1026 0 : dstoffset = stdoffset - SECSPERHOUR;
1027 0 : if (*name == '\0' && !load_ok)
1028 0 : name = TZDEFRULESTRING;
1029 0 : if (*name == ',' || *name == ';')
1030 0 : {
1031 : struct rule start;
1032 : struct rule end;
1033 : int year;
1034 : int yearlim;
1035 : int timecnt;
1036 : pg_time_t janfirst;
1037 0 : int_fast32_t janoffset = 0;
1038 : int yearbeg;
1039 :
1040 0 : ++name;
1041 0 : if ((name = getrule(name, &start)) == NULL)
1042 0 : return false;
1043 0 : if (*name++ != ',')
1044 0 : return false;
1045 0 : if ((name = getrule(name, &end)) == NULL)
1046 0 : return false;
1047 0 : if (*name != '\0')
1048 0 : return false;
1049 0 : sp->typecnt = 2; /* standard time and DST */
1050 :
1051 : /*
1052 : * Two transitions per year, from EPOCH_YEAR forward.
1053 : */
1054 0 : init_ttinfo(&sp->ttis[0], -stdoffset, false, 0);
1055 0 : init_ttinfo(&sp->ttis[1], -dstoffset, true, stdlen + 1);
1056 0 : sp->defaulttype = 0;
1057 0 : timecnt = 0;
1058 0 : janfirst = 0;
1059 0 : yearbeg = EPOCH_YEAR;
1060 :
1061 : do
1062 : {
1063 0 : int_fast32_t yearsecs
1064 0 : = year_lengths[isleap(yearbeg - 1)] * SECSPERDAY;
1065 :
1066 0 : yearbeg--;
1067 0 : if (increment_overflow_time(&janfirst, -yearsecs))
1068 : {
1069 0 : janoffset = -yearsecs;
1070 0 : break;
1071 : }
1072 0 : } while (EPOCH_YEAR - YEARSPERREPEAT / 2 < yearbeg);
1073 :
1074 0 : yearlim = yearbeg + YEARSPERREPEAT + 1;
1075 0 : for (year = yearbeg; year < yearlim; year++)
1076 : {
1077 : int_fast32_t
1078 0 : starttime = transtime(year, &start, stdoffset),
1079 0 : endtime = transtime(year, &end, dstoffset);
1080 : int_fast32_t
1081 0 : yearsecs = (year_lengths[isleap(year)]
1082 : * SECSPERDAY);
1083 0 : bool reversed = endtime < starttime;
1084 :
1085 0 : if (reversed)
1086 : {
1087 0 : int_fast32_t swap = starttime;
1088 :
1089 0 : starttime = endtime;
1090 0 : endtime = swap;
1091 : }
1092 0 : if (reversed
1093 0 : || (starttime < endtime
1094 0 : && (endtime - starttime
1095 : < (yearsecs
1096 0 : + (stdoffset - dstoffset)))))
1097 : {
1098 0 : if (TZ_MAX_TIMES - 2 < timecnt)
1099 0 : break;
1100 0 : sp->ats[timecnt] = janfirst;
1101 0 : if (!increment_overflow_time
1102 : (&sp->ats[timecnt],
1103 : janoffset + starttime))
1104 0 : sp->types[timecnt++] = !reversed;
1105 0 : sp->ats[timecnt] = janfirst;
1106 0 : if (!increment_overflow_time
1107 : (&sp->ats[timecnt],
1108 : janoffset + endtime))
1109 : {
1110 0 : sp->types[timecnt++] = reversed;
1111 0 : yearlim = year + YEARSPERREPEAT + 1;
1112 : }
1113 : }
1114 0 : if (increment_overflow_time
1115 : (&janfirst, janoffset + yearsecs))
1116 0 : break;
1117 0 : janoffset = 0;
1118 : }
1119 0 : sp->timecnt = timecnt;
1120 0 : if (!timecnt)
1121 : {
1122 0 : sp->ttis[0] = sp->ttis[1];
1123 0 : sp->typecnt = 1; /* Perpetual DST. */
1124 : }
1125 0 : else if (YEARSPERREPEAT < year - yearbeg)
1126 0 : sp->goback = sp->goahead = true;
1127 : }
1128 : else
1129 : {
1130 : int_fast32_t theirstdoffset;
1131 : int_fast32_t theirdstoffset;
1132 : int_fast32_t theiroffset;
1133 : bool isdst;
1134 : int i;
1135 : int j;
1136 :
1137 0 : if (*name != '\0')
1138 0 : return false;
1139 :
1140 : /*
1141 : * Initial values of theirstdoffset and theirdstoffset.
1142 : */
1143 0 : theirstdoffset = 0;
1144 0 : for (i = 0; i < sp->timecnt; ++i)
1145 : {
1146 0 : j = sp->types[i];
1147 0 : if (!sp->ttis[j].tt_isdst)
1148 : {
1149 0 : theirstdoffset =
1150 0 : -sp->ttis[j].tt_utoff;
1151 0 : break;
1152 : }
1153 : }
1154 0 : theirdstoffset = 0;
1155 0 : for (i = 0; i < sp->timecnt; ++i)
1156 : {
1157 0 : j = sp->types[i];
1158 0 : if (sp->ttis[j].tt_isdst)
1159 : {
1160 0 : theirdstoffset =
1161 0 : -sp->ttis[j].tt_utoff;
1162 0 : break;
1163 : }
1164 : }
1165 :
1166 : /*
1167 : * Initially we're assumed to be in standard time.
1168 : */
1169 0 : isdst = false;
1170 0 : theiroffset = theirstdoffset;
1171 :
1172 : /*
1173 : * Now juggle transition times and types tracking offsets as you
1174 : * do.
1175 : */
1176 0 : for (i = 0; i < sp->timecnt; ++i)
1177 : {
1178 0 : j = sp->types[i];
1179 0 : sp->types[i] = sp->ttis[j].tt_isdst;
1180 0 : if (sp->ttis[j].tt_ttisut)
1181 : {
1182 : /* No adjustment to transition time */
1183 : }
1184 : else
1185 : {
1186 : /*
1187 : * If daylight saving time is in effect, and the
1188 : * transition time was not specified as standard time, add
1189 : * the daylight saving time offset to the transition time;
1190 : * otherwise, add the standard time offset to the
1191 : * transition time.
1192 : */
1193 : /*
1194 : * Transitions from DST to DDST will effectively disappear
1195 : * since POSIX provides for only one DST offset.
1196 : */
1197 0 : if (isdst && !sp->ttis[j].tt_ttisstd)
1198 : {
1199 0 : sp->ats[i] += dstoffset -
1200 : theirdstoffset;
1201 : }
1202 : else
1203 : {
1204 0 : sp->ats[i] += stdoffset -
1205 : theirstdoffset;
1206 : }
1207 : }
1208 0 : theiroffset = -sp->ttis[j].tt_utoff;
1209 0 : if (sp->ttis[j].tt_isdst)
1210 0 : theirdstoffset = theiroffset;
1211 : else
1212 0 : theirstdoffset = theiroffset;
1213 : }
1214 :
1215 : /*
1216 : * Finally, fill in ttis.
1217 : */
1218 0 : init_ttinfo(&sp->ttis[0], -stdoffset, false, 0);
1219 0 : init_ttinfo(&sp->ttis[1], -dstoffset, true, stdlen + 1);
1220 0 : sp->typecnt = 2;
1221 0 : sp->defaulttype = 0;
1222 : }
1223 : }
1224 : else
1225 : {
1226 104 : dstlen = 0;
1227 104 : sp->typecnt = 1; /* only standard time */
1228 104 : sp->timecnt = 0;
1229 104 : init_ttinfo(&sp->ttis[0], -stdoffset, false, 0);
1230 104 : sp->defaulttype = 0;
1231 : }
1232 104 : sp->charcnt = charcnt;
1233 104 : cp = sp->chars;
1234 104 : memcpy(cp, stdname, stdlen);
1235 104 : cp += stdlen;
1236 104 : *cp++ = '\0';
1237 104 : if (dstlen != 0)
1238 : {
1239 0 : memcpy(cp, dstname, dstlen);
1240 0 : *(cp + dstlen) = '\0';
1241 : }
1242 104 : return true;
1243 : }
1244 :
1245 : static void
1246 0 : gmtload(struct state *const sp)
1247 : {
1248 0 : if (tzload(gmt, NULL, sp, true) != 0)
1249 0 : tzparse(gmt, sp, true);
1250 0 : }
1251 :
1252 :
1253 : /*
1254 : * The easy way to behave "as if no library function calls" localtime
1255 : * is to not call it, so we drop its guts into "localsub", which can be
1256 : * freely called. (And no, the PANS doesn't require the above behavior,
1257 : * but it *is* desirable.)
1258 : */
1259 : static struct pg_tm *
1260 270504 : localsub(struct state const *sp, pg_time_t const *timep,
1261 : struct pg_tm *const tmp)
1262 : {
1263 : const struct ttinfo *ttisp;
1264 : int i;
1265 : struct pg_tm *result;
1266 270504 : const pg_time_t t = *timep;
1267 :
1268 270504 : if (sp == NULL)
1269 0 : return gmtsub(timep, 0, tmp);
1270 270504 : if ((sp->goback && t < sp->ats[0]) ||
1271 270504 : (sp->goahead && t > sp->ats[sp->timecnt - 1]))
1272 : {
1273 0 : pg_time_t newt = t;
1274 : pg_time_t seconds;
1275 : pg_time_t years;
1276 :
1277 0 : if (t < sp->ats[0])
1278 0 : seconds = sp->ats[0] - t;
1279 : else
1280 0 : seconds = t - sp->ats[sp->timecnt - 1];
1281 0 : --seconds;
1282 0 : years = (seconds / SECSPERREPEAT + 1) * YEARSPERREPEAT;
1283 0 : seconds = years * AVGSECSPERYEAR;
1284 0 : if (t < sp->ats[0])
1285 0 : newt += seconds;
1286 : else
1287 0 : newt -= seconds;
1288 0 : if (newt < sp->ats[0] ||
1289 0 : newt > sp->ats[sp->timecnt - 1])
1290 0 : return NULL; /* "cannot happen" */
1291 0 : result = localsub(sp, &newt, tmp);
1292 0 : if (result)
1293 : {
1294 : int_fast64_t newy;
1295 :
1296 0 : newy = result->tm_year;
1297 0 : if (t < sp->ats[0])
1298 0 : newy -= years;
1299 : else
1300 0 : newy += years;
1301 0 : if (!(INT_MIN <= newy && newy <= INT_MAX))
1302 0 : return NULL;
1303 0 : result->tm_year = newy;
1304 : }
1305 0 : return result;
1306 : }
1307 270504 : if (sp->timecnt == 0 || t < sp->ats[0])
1308 : {
1309 270504 : i = sp->defaulttype;
1310 : }
1311 : else
1312 : {
1313 0 : int lo = 1;
1314 0 : int hi = sp->timecnt;
1315 :
1316 0 : while (lo < hi)
1317 : {
1318 0 : int mid = (lo + hi) >> 1;
1319 :
1320 0 : if (t < sp->ats[mid])
1321 0 : hi = mid;
1322 : else
1323 0 : lo = mid + 1;
1324 : }
1325 0 : i = (int) sp->types[lo - 1];
1326 : }
1327 270504 : ttisp = &sp->ttis[i];
1328 :
1329 : /*
1330 : * To get (wrong) behavior that's compatible with System V Release 2.0
1331 : * you'd replace the statement below with t += ttisp->tt_utoff;
1332 : * timesub(&t, 0L, sp, tmp);
1333 : */
1334 270504 : result = timesub(&t, ttisp->tt_utoff, sp, tmp);
1335 270504 : if (result)
1336 : {
1337 270504 : result->tm_isdst = ttisp->tt_isdst;
1338 270504 : result->tm_zone = unconstify(char *, &sp->chars[ttisp->tt_desigidx]);
1339 : }
1340 270504 : return result;
1341 : }
1342 :
1343 :
1344 : struct pg_tm *
1345 270504 : pg_localtime(const pg_time_t *timep, const pg_tz *tz)
1346 : {
1347 270504 : return localsub(&tz->state, timep, &tm);
1348 : }
1349 :
1350 :
1351 : /*
1352 : * gmtsub is to gmtime as localsub is to localtime.
1353 : *
1354 : * Except we have a private "struct state" for GMT, so no sp is passed in.
1355 : */
1356 :
1357 : static struct pg_tm *
1358 0 : gmtsub(pg_time_t const *timep, int_fast32_t offset,
1359 : struct pg_tm *tmp)
1360 : {
1361 : struct pg_tm *result;
1362 :
1363 : /* GMT timezone state data is kept here */
1364 : static struct state *gmtptr = NULL;
1365 :
1366 0 : if (gmtptr == NULL)
1367 : {
1368 : /* Allocate on first use */
1369 0 : gmtptr = (struct state *) malloc(sizeof(struct state));
1370 0 : if (gmtptr == NULL)
1371 0 : return NULL; /* errno should be set by malloc */
1372 0 : gmtload(gmtptr);
1373 : }
1374 :
1375 0 : result = timesub(timep, offset, gmtptr, tmp);
1376 :
1377 : /*
1378 : * Could get fancy here and deliver something such as "+xx" or "-xx" if
1379 : * offset is non-zero, but this is no time for a treasure hunt.
1380 : */
1381 0 : if (offset != 0)
1382 0 : tmp->tm_zone = wildabbr;
1383 : else
1384 0 : tmp->tm_zone = gmtptr->chars;
1385 :
1386 0 : return result;
1387 : }
1388 :
1389 : struct pg_tm *
1390 0 : pg_gmtime(const pg_time_t *timep)
1391 : {
1392 0 : return gmtsub(timep, 0, &tm);
1393 : }
1394 :
1395 : /*
1396 : * Return the number of leap years through the end of the given year
1397 : * where, to make the math easy, the answer for year zero is defined as zero.
1398 : */
1399 :
1400 : static int
1401 1333072 : leaps_thru_end_of_nonneg(int y)
1402 : {
1403 1333072 : return y / 4 - y / 100 + y / 400;
1404 : }
1405 :
1406 : static int
1407 1333072 : leaps_thru_end_of(const int y)
1408 : {
1409 : return (y < 0
1410 0 : ? -1 - leaps_thru_end_of_nonneg(-1 - y)
1411 1333072 : : leaps_thru_end_of_nonneg(y));
1412 : }
1413 :
1414 : static struct pg_tm *
1415 270504 : timesub(const pg_time_t *timep, int_fast32_t offset,
1416 : const struct state *sp, struct pg_tm *tmp)
1417 : {
1418 : const struct lsinfo *lp;
1419 : pg_time_t tdays;
1420 : int idays; /* unsigned would be so 2003 */
1421 : int_fast64_t rem;
1422 : int y;
1423 : const int *ip;
1424 : int_fast64_t corr;
1425 : bool hit;
1426 : int i;
1427 :
1428 270504 : corr = 0;
1429 270504 : hit = false;
1430 270504 : i = (sp == NULL) ? 0 : sp->leapcnt;
1431 270504 : while (--i >= 0)
1432 : {
1433 0 : lp = &sp->lsis[i];
1434 0 : if (*timep >= lp->ls_trans)
1435 : {
1436 0 : corr = lp->ls_corr;
1437 0 : hit = (*timep == lp->ls_trans
1438 0 : && (i == 0 ? 0 : lp[-1].ls_corr) < corr);
1439 0 : break;
1440 : }
1441 : }
1442 270504 : y = EPOCH_YEAR;
1443 270504 : tdays = *timep / SECSPERDAY;
1444 270504 : rem = *timep % SECSPERDAY;
1445 666536 : while (tdays < 0 || tdays >= year_lengths[isleap(y)])
1446 : {
1447 : int newy;
1448 : pg_time_t tdelta;
1449 : int idelta;
1450 : int leapdays;
1451 :
1452 396032 : tdelta = tdays / DAYSPERLYEAR;
1453 396032 : if (!((!TYPE_SIGNED(pg_time_t) || INT_MIN <= tdelta)
1454 : && tdelta <= INT_MAX))
1455 0 : goto out_of_range;
1456 396032 : idelta = tdelta;
1457 396032 : if (idelta == 0)
1458 117312 : idelta = (tdays < 0) ? -1 : 1;
1459 396032 : newy = y;
1460 396032 : if (increment_overflow(&newy, idelta))
1461 0 : goto out_of_range;
1462 396032 : leapdays = leaps_thru_end_of(newy - 1) -
1463 396032 : leaps_thru_end_of(y - 1);
1464 396032 : tdays -= ((pg_time_t) newy - y) * DAYSPERNYEAR;
1465 396032 : tdays -= leapdays;
1466 396032 : y = newy;
1467 : }
1468 :
1469 : /*
1470 : * Given the range, we can now fearlessly cast...
1471 : */
1472 270504 : idays = tdays;
1473 270504 : rem += offset - corr;
1474 270504 : while (rem < 0)
1475 : {
1476 0 : rem += SECSPERDAY;
1477 0 : --idays;
1478 : }
1479 270504 : while (rem >= SECSPERDAY)
1480 : {
1481 0 : rem -= SECSPERDAY;
1482 0 : ++idays;
1483 : }
1484 270504 : while (idays < 0)
1485 : {
1486 0 : if (increment_overflow(&y, -1))
1487 0 : goto out_of_range;
1488 0 : idays += year_lengths[isleap(y)];
1489 : }
1490 270504 : while (idays >= year_lengths[isleap(y)])
1491 : {
1492 0 : idays -= year_lengths[isleap(y)];
1493 0 : if (increment_overflow(&y, 1))
1494 0 : goto out_of_range;
1495 : }
1496 270504 : tmp->tm_year = y;
1497 270504 : if (increment_overflow(&tmp->tm_year, -TM_YEAR_BASE))
1498 0 : goto out_of_range;
1499 270504 : tmp->tm_yday = idays;
1500 :
1501 : /*
1502 : * The "extra" mods below avoid overflow problems.
1503 : */
1504 270504 : tmp->tm_wday = EPOCH_WDAY +
1505 270504 : ((y - EPOCH_YEAR) % DAYSPERWEEK) *
1506 270504 : (DAYSPERNYEAR % DAYSPERWEEK) +
1507 270504 : leaps_thru_end_of(y - 1) -
1508 270504 : leaps_thru_end_of(EPOCH_YEAR - 1) +
1509 : idays;
1510 270504 : tmp->tm_wday %= DAYSPERWEEK;
1511 270504 : if (tmp->tm_wday < 0)
1512 1768 : tmp->tm_wday += DAYSPERWEEK;
1513 270504 : tmp->tm_hour = (int) (rem / SECSPERHOUR);
1514 270504 : rem %= SECSPERHOUR;
1515 270504 : tmp->tm_min = (int) (rem / SECSPERMIN);
1516 :
1517 : /*
1518 : * A positive leap second requires a special representation. This uses
1519 : * "... ??:59:60" et seq.
1520 : */
1521 270504 : tmp->tm_sec = (int) (rem % SECSPERMIN) + hit;
1522 270504 : ip = mon_lengths[isleap(y)];
1523 1761032 : for (tmp->tm_mon = 0; idays >= ip[tmp->tm_mon]; ++(tmp->tm_mon))
1524 1490528 : idays -= ip[tmp->tm_mon];
1525 270504 : tmp->tm_mday = (int) (idays + 1);
1526 270504 : tmp->tm_isdst = 0;
1527 270504 : tmp->tm_gmtoff = offset;
1528 270504 : return tmp;
1529 :
1530 0 : out_of_range:
1531 0 : errno = EOVERFLOW;
1532 0 : return NULL;
1533 : }
1534 :
1535 : /*
1536 : * Normalize logic courtesy Paul Eggert.
1537 : */
1538 :
1539 : static bool
1540 666536 : increment_overflow(int *ip, int j)
1541 : {
1542 666536 : int const i = *ip;
1543 :
1544 : /*----------
1545 : * If i >= 0 there can only be overflow if i + j > INT_MAX
1546 : * or if j > INT_MAX - i; given i >= 0, INT_MAX - i cannot overflow.
1547 : * If i < 0 there can only be overflow if i + j < INT_MIN
1548 : * or if j < INT_MIN - i; given i < 0, INT_MIN - i cannot overflow.
1549 : *----------
1550 : */
1551 666536 : if ((i >= 0) ? (j > INT_MAX - i) : (j < INT_MIN - i))
1552 0 : return true;
1553 666536 : *ip += j;
1554 666536 : return false;
1555 : }
1556 :
1557 : static bool
1558 0 : increment_overflow_time(pg_time_t *tp, int_fast32_t j)
1559 : {
1560 : /*----------
1561 : * This is like
1562 : * 'if (! (TIME_T_MIN <= *tp + j && *tp + j <= TIME_T_MAX)) ...',
1563 : * except that it does the right thing even if *tp + j would overflow.
1564 : *----------
1565 : */
1566 0 : if (!(j < 0
1567 0 : ? (TYPE_SIGNED(pg_time_t) ? TIME_T_MIN - j <= *tp : -1 - j < *tp)
1568 0 : : *tp <= TIME_T_MAX - j))
1569 0 : return true;
1570 0 : *tp += j;
1571 0 : return false;
1572 : }
1573 :
1574 : static int_fast64_t
1575 0 : leapcorr(struct state const *sp, pg_time_t t)
1576 : {
1577 : struct lsinfo const *lp;
1578 : int i;
1579 :
1580 0 : i = sp->leapcnt;
1581 0 : while (--i >= 0)
1582 : {
1583 0 : lp = &sp->lsis[i];
1584 0 : if (t >= lp->ls_trans)
1585 0 : return lp->ls_corr;
1586 : }
1587 0 : return 0;
1588 : }
1589 :
1590 : /*
1591 : * Find the next DST transition time in the given zone after the given time
1592 : *
1593 : * *timep and *tz are input arguments, the other parameters are output values.
1594 : *
1595 : * When the function result is 1, *boundary is set to the pg_time_t
1596 : * representation of the next DST transition time after *timep,
1597 : * *before_gmtoff and *before_isdst are set to the GMT offset and isdst
1598 : * state prevailing just before that boundary (in particular, the state
1599 : * prevailing at *timep), and *after_gmtoff and *after_isdst are set to
1600 : * the state prevailing just after that boundary.
1601 : *
1602 : * When the function result is 0, there is no known DST transition
1603 : * after *timep, but *before_gmtoff and *before_isdst indicate the GMT
1604 : * offset and isdst state prevailing at *timep. (This would occur in
1605 : * DST-less time zones, or if a zone has permanently ceased using DST.)
1606 : *
1607 : * A function result of -1 indicates failure (this case does not actually
1608 : * occur in our current implementation).
1609 : */
1610 : int
1611 0 : pg_next_dst_boundary(const pg_time_t *timep,
1612 : long int *before_gmtoff,
1613 : int *before_isdst,
1614 : pg_time_t *boundary,
1615 : long int *after_gmtoff,
1616 : int *after_isdst,
1617 : const pg_tz *tz)
1618 : {
1619 : const struct state *sp;
1620 : const struct ttinfo *ttisp;
1621 : int i;
1622 : int j;
1623 0 : const pg_time_t t = *timep;
1624 :
1625 0 : sp = &tz->state;
1626 0 : if (sp->timecnt == 0)
1627 : {
1628 : /* non-DST zone, use the defaulttype */
1629 0 : ttisp = &sp->ttis[sp->defaulttype];
1630 0 : *before_gmtoff = ttisp->tt_utoff;
1631 0 : *before_isdst = ttisp->tt_isdst;
1632 0 : return 0;
1633 : }
1634 0 : if ((sp->goback && t < sp->ats[0]) ||
1635 0 : (sp->goahead && t > sp->ats[sp->timecnt - 1]))
1636 : {
1637 : /* For values outside the transition table, extrapolate */
1638 0 : pg_time_t newt = t;
1639 : pg_time_t seconds;
1640 : pg_time_t tcycles;
1641 : int64 icycles;
1642 : int result;
1643 :
1644 0 : if (t < sp->ats[0])
1645 0 : seconds = sp->ats[0] - t;
1646 : else
1647 0 : seconds = t - sp->ats[sp->timecnt - 1];
1648 0 : --seconds;
1649 0 : tcycles = seconds / YEARSPERREPEAT / AVGSECSPERYEAR;
1650 0 : ++tcycles;
1651 0 : icycles = tcycles;
1652 0 : if (tcycles - icycles >= 1 || icycles - tcycles >= 1)
1653 0 : return -1;
1654 0 : seconds = icycles;
1655 0 : seconds *= YEARSPERREPEAT;
1656 0 : seconds *= AVGSECSPERYEAR;
1657 0 : if (t < sp->ats[0])
1658 0 : newt += seconds;
1659 : else
1660 0 : newt -= seconds;
1661 0 : if (newt < sp->ats[0] ||
1662 0 : newt > sp->ats[sp->timecnt - 1])
1663 0 : return -1; /* "cannot happen" */
1664 :
1665 0 : result = pg_next_dst_boundary(&newt, before_gmtoff,
1666 : before_isdst,
1667 : boundary,
1668 : after_gmtoff,
1669 : after_isdst,
1670 : tz);
1671 0 : if (t < sp->ats[0])
1672 0 : *boundary -= seconds;
1673 : else
1674 0 : *boundary += seconds;
1675 0 : return result;
1676 : }
1677 :
1678 0 : if (t >= sp->ats[sp->timecnt - 1])
1679 : {
1680 : /* No known transition > t, so use last known segment's type */
1681 0 : i = sp->types[sp->timecnt - 1];
1682 0 : ttisp = &sp->ttis[i];
1683 0 : *before_gmtoff = ttisp->tt_utoff;
1684 0 : *before_isdst = ttisp->tt_isdst;
1685 0 : return 0;
1686 : }
1687 0 : if (t < sp->ats[0])
1688 : {
1689 : /* For "before", use the defaulttype */
1690 0 : ttisp = &sp->ttis[sp->defaulttype];
1691 0 : *before_gmtoff = ttisp->tt_utoff;
1692 0 : *before_isdst = ttisp->tt_isdst;
1693 0 : *boundary = sp->ats[0];
1694 : /* And for "after", use the first segment's type */
1695 0 : i = sp->types[0];
1696 0 : ttisp = &sp->ttis[i];
1697 0 : *after_gmtoff = ttisp->tt_utoff;
1698 0 : *after_isdst = ttisp->tt_isdst;
1699 0 : return 1;
1700 : }
1701 : /* Else search to find the boundary following t */
1702 : {
1703 0 : int lo = 1;
1704 0 : int hi = sp->timecnt - 1;
1705 :
1706 0 : while (lo < hi)
1707 : {
1708 0 : int mid = (lo + hi) >> 1;
1709 :
1710 0 : if (t < sp->ats[mid])
1711 0 : hi = mid;
1712 : else
1713 0 : lo = mid + 1;
1714 : }
1715 0 : i = lo;
1716 : }
1717 0 : j = sp->types[i - 1];
1718 0 : ttisp = &sp->ttis[j];
1719 0 : *before_gmtoff = ttisp->tt_utoff;
1720 0 : *before_isdst = ttisp->tt_isdst;
1721 0 : *boundary = sp->ats[i];
1722 0 : j = sp->types[i];
1723 0 : ttisp = &sp->ttis[j];
1724 0 : *after_gmtoff = ttisp->tt_utoff;
1725 0 : *after_isdst = ttisp->tt_isdst;
1726 0 : return 1;
1727 : }
1728 :
1729 : /*
1730 : * Identify a timezone abbreviation's meaning in the given zone
1731 : *
1732 : * Determine the GMT offset and DST flag associated with the abbreviation.
1733 : * This is generally used only when the abbreviation has actually changed
1734 : * meaning over time; therefore, we also take a UTC cutoff time, and return
1735 : * the meaning in use at or most recently before that time, or the meaning
1736 : * in first use after that time if the abbrev was never used before that.
1737 : *
1738 : * On success, returns true and sets *gmtoff and *isdst. If the abbreviation
1739 : * was never used at all in this zone, returns false.
1740 : *
1741 : * Note: abbrev is matched case-sensitively; it should be all-upper-case.
1742 : */
1743 : bool
1744 0 : pg_interpret_timezone_abbrev(const char *abbrev,
1745 : const pg_time_t *timep,
1746 : long int *gmtoff,
1747 : int *isdst,
1748 : const pg_tz *tz)
1749 : {
1750 : const struct state *sp;
1751 : const char *abbrs;
1752 : const struct ttinfo *ttisp;
1753 : int abbrind;
1754 : int cutoff;
1755 : int i;
1756 0 : const pg_time_t t = *timep;
1757 :
1758 0 : sp = &tz->state;
1759 :
1760 : /*
1761 : * Locate the abbreviation in the zone's abbreviation list. We assume
1762 : * there are not duplicates in the list.
1763 : */
1764 0 : abbrs = sp->chars;
1765 0 : abbrind = 0;
1766 0 : while (abbrind < sp->charcnt)
1767 : {
1768 0 : if (strcmp(abbrev, abbrs + abbrind) == 0)
1769 0 : break;
1770 0 : while (abbrs[abbrind] != '\0')
1771 0 : abbrind++;
1772 0 : abbrind++;
1773 : }
1774 0 : if (abbrind >= sp->charcnt)
1775 0 : return false; /* not there! */
1776 :
1777 : /*
1778 : * Unlike pg_next_dst_boundary, we needn't sweat about extrapolation
1779 : * (goback/goahead zones). Finding the newest or oldest meaning of the
1780 : * abbreviation should get us what we want, since extrapolation would just
1781 : * be repeating the newest or oldest meanings.
1782 : *
1783 : * Use binary search to locate the first transition > cutoff time. (Note
1784 : * that sp->timecnt could be zero, in which case this loop does nothing
1785 : * and only the defaulttype entry will be checked.)
1786 : */
1787 : {
1788 0 : int lo = 0;
1789 0 : int hi = sp->timecnt;
1790 :
1791 0 : while (lo < hi)
1792 : {
1793 0 : int mid = (lo + hi) >> 1;
1794 :
1795 0 : if (t < sp->ats[mid])
1796 0 : hi = mid;
1797 : else
1798 0 : lo = mid + 1;
1799 : }
1800 0 : cutoff = lo;
1801 : }
1802 :
1803 : /*
1804 : * Scan backwards to find the latest interval using the given abbrev
1805 : * before the cutoff time.
1806 : */
1807 0 : for (i = cutoff - 1; i >= 0; i--)
1808 : {
1809 0 : ttisp = &sp->ttis[sp->types[i]];
1810 0 : if (ttisp->tt_desigidx == abbrind)
1811 : {
1812 0 : *gmtoff = ttisp->tt_utoff;
1813 0 : *isdst = ttisp->tt_isdst;
1814 0 : return true;
1815 : }
1816 : }
1817 :
1818 : /*
1819 : * Not found yet; check the defaulttype, which is notionally the era
1820 : * before any of the entries in sp->types[].
1821 : */
1822 0 : ttisp = &sp->ttis[sp->defaulttype];
1823 0 : if (ttisp->tt_desigidx == abbrind)
1824 : {
1825 0 : *gmtoff = ttisp->tt_utoff;
1826 0 : *isdst = ttisp->tt_isdst;
1827 0 : return true;
1828 : }
1829 :
1830 : /*
1831 : * Not there, so scan forwards to find the first one after the cutoff.
1832 : */
1833 0 : for (i = cutoff; i < sp->timecnt; i++)
1834 : {
1835 0 : ttisp = &sp->ttis[sp->types[i]];
1836 0 : if (ttisp->tt_desigidx == abbrind)
1837 : {
1838 0 : *gmtoff = ttisp->tt_utoff;
1839 0 : *isdst = ttisp->tt_isdst;
1840 0 : return true;
1841 : }
1842 : }
1843 :
1844 0 : return false; /* hm, not actually used in any interval? */
1845 : }
1846 :
1847 : /*
1848 : * Detect whether a timezone abbreviation is defined within the given zone.
1849 : *
1850 : * This is similar to pg_interpret_timezone_abbrev() but is not concerned
1851 : * with a specific point in time. We want to know if the abbreviation is
1852 : * known at all, and if so whether it has one meaning or several.
1853 : *
1854 : * Returns true if the abbreviation is known, false if not.
1855 : * If the abbreviation is known and has a single meaning (only one value
1856 : * of gmtoff/isdst), sets *isfixed = true and sets *gmtoff and *isdst.
1857 : * If there are multiple meanings, sets *isfixed = false.
1858 : *
1859 : * Note: abbrev is matched case-sensitively; it should be all-upper-case.
1860 : */
1861 : bool
1862 0 : pg_timezone_abbrev_is_known(const char *abbrev,
1863 : bool *isfixed,
1864 : long int *gmtoff,
1865 : int *isdst,
1866 : const pg_tz *tz)
1867 : {
1868 0 : bool result = false;
1869 0 : const struct state *sp = &tz->state;
1870 : const char *abbrs;
1871 : int abbrind;
1872 :
1873 : /*
1874 : * Locate the abbreviation in the zone's abbreviation list. We assume
1875 : * there are not duplicates in the list.
1876 : */
1877 0 : abbrs = sp->chars;
1878 0 : abbrind = 0;
1879 0 : while (abbrind < sp->charcnt)
1880 : {
1881 0 : if (strcmp(abbrev, abbrs + abbrind) == 0)
1882 0 : break;
1883 0 : while (abbrs[abbrind] != '\0')
1884 0 : abbrind++;
1885 0 : abbrind++;
1886 : }
1887 0 : if (abbrind >= sp->charcnt)
1888 0 : return false; /* definitely not there */
1889 :
1890 : /*
1891 : * Scan the ttinfo array to find uses of the abbreviation.
1892 : */
1893 0 : for (int i = 0; i < sp->typecnt; i++)
1894 : {
1895 0 : const struct ttinfo *ttisp = &sp->ttis[i];
1896 :
1897 0 : if (ttisp->tt_desigidx == abbrind)
1898 : {
1899 0 : if (!result)
1900 : {
1901 : /* First usage */
1902 0 : *isfixed = true; /* for the moment */
1903 0 : *gmtoff = ttisp->tt_utoff;
1904 0 : *isdst = ttisp->tt_isdst;
1905 0 : result = true;
1906 : }
1907 : else
1908 : {
1909 : /* Second or later usage, does it match? */
1910 0 : if (*gmtoff != ttisp->tt_utoff ||
1911 0 : *isdst != ttisp->tt_isdst)
1912 : {
1913 0 : *isfixed = false;
1914 0 : break; /* no point in looking further */
1915 : }
1916 : }
1917 : }
1918 : }
1919 :
1920 0 : return result;
1921 : }
1922 :
1923 : /*
1924 : * Iteratively fetch all the abbreviations used in the given time zone.
1925 : *
1926 : * *indx is a state counter that the caller must initialize to zero
1927 : * before the first call, and not touch between calls.
1928 : *
1929 : * Returns the next known abbreviation, or NULL if there are no more.
1930 : *
1931 : * Note: the caller typically applies pg_interpret_timezone_abbrev()
1932 : * to each result. While that nominally results in O(N^2) time spent
1933 : * searching the sp->chars[] array, we don't expect any zone to have
1934 : * enough abbreviations to make that meaningful.
1935 : */
1936 : const char *
1937 0 : pg_get_next_timezone_abbrev(int *indx,
1938 : const pg_tz *tz)
1939 : {
1940 : const char *result;
1941 0 : const struct state *sp = &tz->state;
1942 : const char *abbrs;
1943 : int abbrind;
1944 :
1945 : /* If we're still in range, the result is the current abbrev. */
1946 0 : abbrs = sp->chars;
1947 0 : abbrind = *indx;
1948 0 : if (abbrind < 0 || abbrind >= sp->charcnt)
1949 0 : return NULL;
1950 0 : result = abbrs + abbrind;
1951 :
1952 : /* Advance *indx past this abbrev and its trailing null. */
1953 0 : while (abbrs[abbrind] != '\0')
1954 0 : abbrind++;
1955 0 : abbrind++;
1956 0 : *indx = abbrind;
1957 :
1958 0 : return result;
1959 : }
1960 :
1961 : /*
1962 : * If the given timezone uses only one GMT offset, store that offset
1963 : * into *gmtoff and return true, else return false.
1964 : */
1965 : bool
1966 0 : pg_get_timezone_offset(const pg_tz *tz, long int *gmtoff)
1967 : {
1968 : /*
1969 : * The zone could have more than one ttinfo, if it's historically used
1970 : * more than one abbreviation. We return true as long as they all have
1971 : * the same gmtoff.
1972 : */
1973 : const struct state *sp;
1974 : int i;
1975 :
1976 0 : sp = &tz->state;
1977 0 : for (i = 1; i < sp->typecnt; i++)
1978 : {
1979 0 : if (sp->ttis[i].tt_utoff != sp->ttis[0].tt_utoff)
1980 0 : return false;
1981 : }
1982 0 : *gmtoff = sp->ttis[0].tt_utoff;
1983 0 : return true;
1984 : }
1985 :
1986 : /*
1987 : * Return the name of the current timezone
1988 : */
1989 : const char *
1990 0 : pg_get_timezone_name(pg_tz *tz)
1991 : {
1992 0 : if (tz)
1993 0 : return tz->TZname;
1994 0 : return NULL;
1995 : }
1996 :
1997 : /*
1998 : * Check whether timezone is acceptable.
1999 : *
2000 : * What we are doing here is checking for leap-second-aware timekeeping.
2001 : * We need to reject such TZ settings because they'll wreak havoc with our
2002 : * date/time arithmetic.
2003 : */
2004 : bool
2005 104 : pg_tz_acceptable(pg_tz *tz)
2006 : {
2007 : struct pg_tm *tt;
2008 : pg_time_t time2000;
2009 :
2010 : /*
2011 : * To detect leap-second timekeeping, run pg_localtime for what should be
2012 : * GMT midnight, 2000-01-01. Insist that the tm_sec value be zero; any
2013 : * other result has to be due to leap seconds.
2014 : */
2015 104 : time2000 = (POSTGRES_EPOCH_JDATE - UNIX_EPOCH_JDATE) * SECS_PER_DAY;
2016 104 : tt = pg_localtime(&time2000, tz);
2017 104 : if (!tt || tt->tm_sec != 0)
2018 0 : return false;
2019 :
2020 104 : return true;
2021 : }
|
