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findtimezone.c
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1 /*-------------------------------------------------------------------------
2  *
3  * findtimezone.c
4  * Functions for determining the default timezone to use.
5  *
6  * Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
7  *
8  * IDENTIFICATION
9  * src/bin/initdb/findtimezone.c
10  *
11  *-------------------------------------------------------------------------
12  */
13 #include "postgres_fe.h"
14 
15 #include <fcntl.h>
16 #include <sys/stat.h>
17 #include <time.h>
18 #include <unistd.h>
19 
20 #include "pgtz.h"
21 
22 /* Ideally this would be in a .h file, but it hardly seems worth the trouble */
23 extern const char *select_default_timezone(const char *share_path);
24 
25 
26 #ifndef SYSTEMTZDIR
27 static char tzdirpath[MAXPGPATH];
28 #endif
29 
30 
31 /*
32  * Return full pathname of timezone data directory
33  *
34  * In this file, tzdirpath is assumed to be set up by select_default_timezone.
35  */
36 static const char *
37 pg_TZDIR(void)
38 {
39 #ifndef SYSTEMTZDIR
40  /* normal case: timezone stuff is under our share dir */
41  return tzdirpath;
42 #else
43  /* we're configured to use system's timezone database */
44  return SYSTEMTZDIR;
45 #endif
46 }
47 
48 
49 /*
50  * Given a timezone name, open() the timezone data file. Return the
51  * file descriptor if successful, -1 if not.
52  *
53  * This is simpler than the backend function of the same name because
54  * we assume that the input string has the correct case already, so there
55  * is no need for case-folding. (This is obviously true if we got the file
56  * name from the filesystem to start with. The only other place it can come
57  * from is the environment variable TZ, and there seems no need to allow
58  * case variation in that; other programs aren't likely to.)
59  *
60  * If "canonname" is not NULL, then on success the canonical spelling of the
61  * given name is stored there (the buffer must be > TZ_STRLEN_MAX bytes!).
62  * This is redundant but kept for compatibility with the backend code.
63  */
64 int
65 pg_open_tzfile(const char *name, char *canonname)
66 {
67  char fullname[MAXPGPATH];
68 
69  if (canonname)
70  strlcpy(canonname, name, TZ_STRLEN_MAX + 1);
71 
72  strlcpy(fullname, pg_TZDIR(), sizeof(fullname));
73  if (strlen(fullname) + 1 + strlen(name) >= MAXPGPATH)
74  return -1; /* not gonna fit */
75  strcat(fullname, "/");
76  strcat(fullname, name);
77 
78  return open(fullname, O_RDONLY | PG_BINARY, 0);
79 }
80 
81 
82 
83 /*
84  * Load a timezone definition.
85  * Does not verify that the timezone is acceptable!
86  *
87  * This corresponds to the backend's pg_tzset(), except that we only support
88  * one loaded timezone at a time.
89  */
90 static pg_tz *
91 pg_load_tz(const char *name)
92 {
93  static pg_tz tz;
94 
95  if (strlen(name) > TZ_STRLEN_MAX)
96  return NULL; /* not going to fit */
97 
98  /*
99  * "GMT" is always sent to tzparse(); see comments for pg_tzset().
100  */
101  if (strcmp(name, "GMT") == 0)
102  {
103  if (!tzparse(name, &tz.state, true))
104  {
105  /* This really, really should not happen ... */
106  return NULL;
107  }
108  }
109  else if (tzload(name, NULL, &tz.state, true) != 0)
110  {
111  if (name[0] == ':' || !tzparse(name, &tz.state, false))
112  {
113  return NULL; /* unknown timezone */
114  }
115  }
116 
117  strcpy(tz.TZname, name);
118 
119  return &tz;
120 }
121 
122 
123 /*
124  * The following block of code attempts to determine which timezone in our
125  * timezone database is the best match for the active system timezone.
126  *
127  * On most systems, we rely on trying to match the observable behavior of
128  * the C library's localtime() function. The database zone that matches
129  * furthest into the past is the one to use. Often there will be several
130  * zones with identical rankings (since the IANA database assigns multiple
131  * names to many zones). We break ties by first checking for "preferred"
132  * names (such as "UTC"), and then arbitrarily by preferring shorter, then
133  * alphabetically earlier zone names. (If we did not explicitly prefer
134  * "UTC", we would get the alias name "UCT" instead due to alphabetic
135  * ordering.)
136  *
137  * Many modern systems use the IANA database, so if we can determine the
138  * system's idea of which zone it is using and its behavior matches our zone
139  * of the same name, we can skip the rather-expensive search through all the
140  * zones in our database. This short-circuit path also ensures that we spell
141  * the zone name the same way the system setting does, even in the presence
142  * of multiple aliases for the same zone.
143  *
144  * Win32's native knowledge about timezones appears to be too incomplete
145  * and too different from the IANA database for the above matching strategy
146  * to be of any use. But there is just a limited number of timezones
147  * available, so we can rely on a handmade mapping table instead.
148  */
149 
150 #ifndef WIN32
151 
152 #define T_DAY ((time_t) (60*60*24))
153 #define T_WEEK ((time_t) (60*60*24*7))
154 #define T_MONTH ((time_t) (60*60*24*31))
155 
156 #define MAX_TEST_TIMES (52*100) /* 100 years */
157 
158 struct tztry
159 {
162 };
163 
164 static bool check_system_link_file(const char *linkname, struct tztry *tt,
165  char *bestzonename);
166 static void scan_available_timezones(char *tzdir, char *tzdirsub,
167  struct tztry *tt,
168  int *bestscore, char *bestzonename);
169 
170 
171 /*
172  * Get GMT offset from a system struct tm
173  */
174 static int
176 {
177 #if defined(HAVE_STRUCT_TM_TM_ZONE)
178  return tm->tm_gmtoff;
179 #elif defined(HAVE_INT_TIMEZONE)
180  return -TIMEZONE_GLOBAL;
181 #else
182 #error No way to determine TZ? Can this happen?
183 #endif
184 }
185 
186 /*
187  * Convenience subroutine to convert y/m/d to time_t (NOT pg_time_t)
188  */
189 static time_t
190 build_time_t(int year, int month, int day)
191 {
192  struct tm tm;
193 
194  memset(&tm, 0, sizeof(tm));
195  tm.tm_mday = day;
196  tm.tm_mon = month - 1;
197  tm.tm_year = year - 1900;
198 
199  return mktime(&tm);
200 }
201 
202 /*
203  * Does a system tm value match one we computed ourselves?
204  */
205 static bool
206 compare_tm(struct tm *s, struct pg_tm *p)
207 {
208  if (s->tm_sec != p->tm_sec ||
209  s->tm_min != p->tm_min ||
210  s->tm_hour != p->tm_hour ||
211  s->tm_mday != p->tm_mday ||
212  s->tm_mon != p->tm_mon ||
213  s->tm_year != p->tm_year ||
214  s->tm_wday != p->tm_wday ||
215  s->tm_yday != p->tm_yday ||
216  s->tm_isdst != p->tm_isdst)
217  return false;
218  return true;
219 }
220 
221 /*
222  * See how well a specific timezone setting matches the system behavior
223  *
224  * We score a timezone setting according to the number of test times it
225  * matches. (The test times are ordered later-to-earlier, but this routine
226  * doesn't actually know that; it just scans until the first non-match.)
227  *
228  * We return -1 for a completely unusable setting; this is worse than the
229  * score of zero for a setting that works but matches not even the first
230  * test time.
231  */
232 static int
233 score_timezone(const char *tzname, struct tztry *tt)
234 {
235  int i;
236  pg_time_t pgtt;
237  struct tm *systm;
238  struct pg_tm *pgtm;
239  char cbuf[TZ_STRLEN_MAX + 1];
240  pg_tz *tz;
241 
242  /* Load timezone definition */
243  tz = pg_load_tz(tzname);
244  if (!tz)
245  return -1; /* unrecognized zone name */
246 
247  /* Reject if leap seconds involved */
248  if (!pg_tz_acceptable(tz))
249  {
250 #ifdef DEBUG_IDENTIFY_TIMEZONE
251  fprintf(stderr, "Reject TZ \"%s\": uses leap seconds\n", tzname);
252 #endif
253  return -1;
254  }
255 
256  /* Check for match at all the test times */
257  for (i = 0; i < tt->n_test_times; i++)
258  {
259  pgtt = (pg_time_t) (tt->test_times[i]);
260  pgtm = pg_localtime(&pgtt, tz);
261  if (!pgtm)
262  return -1; /* probably shouldn't happen */
263  systm = localtime(&(tt->test_times[i]));
264  if (!systm)
265  {
266 #ifdef DEBUG_IDENTIFY_TIMEZONE
267  fprintf(stderr, "TZ \"%s\" scores %d: at %ld %04d-%02d-%02d %02d:%02d:%02d %s, system had no data\n",
268  tzname, i, (long) pgtt,
269  pgtm->tm_year + 1900, pgtm->tm_mon + 1, pgtm->tm_mday,
270  pgtm->tm_hour, pgtm->tm_min, pgtm->tm_sec,
271  pgtm->tm_isdst ? "dst" : "std");
272 #endif
273  return i;
274  }
275  if (!compare_tm(systm, pgtm))
276  {
277 #ifdef DEBUG_IDENTIFY_TIMEZONE
278  fprintf(stderr, "TZ \"%s\" scores %d: at %ld %04d-%02d-%02d %02d:%02d:%02d %s versus %04d-%02d-%02d %02d:%02d:%02d %s\n",
279  tzname, i, (long) pgtt,
280  pgtm->tm_year + 1900, pgtm->tm_mon + 1, pgtm->tm_mday,
281  pgtm->tm_hour, pgtm->tm_min, pgtm->tm_sec,
282  pgtm->tm_isdst ? "dst" : "std",
283  systm->tm_year + 1900, systm->tm_mon + 1, systm->tm_mday,
284  systm->tm_hour, systm->tm_min, systm->tm_sec,
285  systm->tm_isdst ? "dst" : "std");
286 #endif
287  return i;
288  }
289  if (systm->tm_isdst >= 0)
290  {
291  /* Check match of zone names, too */
292  if (pgtm->tm_zone == NULL)
293  return -1; /* probably shouldn't happen */
294  memset(cbuf, 0, sizeof(cbuf));
295  strftime(cbuf, sizeof(cbuf) - 1, "%Z", systm); /* zone abbr */
296  if (strcmp(cbuf, pgtm->tm_zone) != 0)
297  {
298 #ifdef DEBUG_IDENTIFY_TIMEZONE
299  fprintf(stderr, "TZ \"%s\" scores %d: at %ld \"%s\" versus \"%s\"\n",
300  tzname, i, (long) pgtt,
301  pgtm->tm_zone, cbuf);
302 #endif
303  return i;
304  }
305  }
306  }
307 
308 #ifdef DEBUG_IDENTIFY_TIMEZONE
309  fprintf(stderr, "TZ \"%s\" gets max score %d\n", tzname, i);
310 #endif
311 
312  return i;
313 }
314 
315 /*
316  * Test whether given zone name is a perfect match to localtime() behavior
317  */
318 static bool
319 perfect_timezone_match(const char *tzname, struct tztry *tt)
320 {
321  return (score_timezone(tzname, tt) == tt->n_test_times);
322 }
323 
324 
325 /*
326  * Try to identify a timezone name (in our terminology) that best matches the
327  * observed behavior of the system localtime() function.
328  */
329 static const char *
331 {
332  static char resultbuf[TZ_STRLEN_MAX + 1];
333  time_t tnow;
334  time_t t;
335  struct tztry tt;
336  struct tm *tm;
337  int thisyear;
338  int bestscore;
339  char tmptzdir[MAXPGPATH];
340  int std_ofs;
341  char std_zone_name[TZ_STRLEN_MAX + 1],
342  dst_zone_name[TZ_STRLEN_MAX + 1];
343  char cbuf[TZ_STRLEN_MAX + 1];
344 
345  /* Initialize OS timezone library */
346  tzset();
347 
348  /*
349  * Set up the list of dates to be probed to see how well our timezone
350  * matches the system zone. We first probe January and July of the
351  * current year; this serves to quickly eliminate the vast majority of the
352  * TZ database entries. If those dates match, we probe every week for 100
353  * years backwards from the current July. (Weekly resolution is good
354  * enough to identify DST transition rules, since everybody switches on
355  * Sundays.) This is sufficient to cover most of the Unix time_t range,
356  * and we don't want to look further than that since many systems won't
357  * have sane TZ behavior further back anyway. The further back the zone
358  * matches, the better we score it. This may seem like a rather random
359  * way of doing things, but experience has shown that system-supplied
360  * timezone definitions are likely to have DST behavior that is right for
361  * the recent past and not so accurate further back. Scoring in this way
362  * allows us to recognize zones that have some commonality with the IANA
363  * database, without insisting on exact match. (Note: we probe Thursdays,
364  * not Sundays, to avoid triggering DST-transition bugs in localtime
365  * itself.)
366  */
367  tnow = time(NULL);
368  tm = localtime(&tnow);
369  if (!tm)
370  return NULL; /* give up if localtime is broken... */
371  thisyear = tm->tm_year + 1900;
372 
373  t = build_time_t(thisyear, 1, 15);
374 
375  /*
376  * Round back to GMT midnight Thursday. This depends on the knowledge
377  * that the time_t origin is Thu Jan 01 1970. (With a different origin
378  * we'd be probing some other day of the week, but it wouldn't matter
379  * anyway unless localtime() had DST-transition bugs.)
380  */
381  t -= (t % T_WEEK);
382 
383  tt.n_test_times = 0;
384  tt.test_times[tt.n_test_times++] = t;
385 
386  t = build_time_t(thisyear, 7, 15);
387  t -= (t % T_WEEK);
388 
389  tt.test_times[tt.n_test_times++] = t;
390 
391  while (tt.n_test_times < MAX_TEST_TIMES)
392  {
393  t -= T_WEEK;
394  tt.test_times[tt.n_test_times++] = t;
395  }
396 
397  /*
398  * Try to avoid the brute-force search by seeing if we can recognize the
399  * system's timezone setting directly.
400  *
401  * Currently we just check /etc/localtime; there are other conventions for
402  * this, but that seems to be the only one used on enough platforms to be
403  * worth troubling over.
404  */
405  if (check_system_link_file("/etc/localtime", &tt, resultbuf))
406  return resultbuf;
407 
408  /* No luck, so search for the best-matching timezone file */
409  strlcpy(tmptzdir, pg_TZDIR(), sizeof(tmptzdir));
410  bestscore = -1;
411  resultbuf[0] = '\0';
412  scan_available_timezones(tmptzdir, tmptzdir + strlen(tmptzdir) + 1,
413  &tt,
414  &bestscore, resultbuf);
415  if (bestscore > 0)
416  {
417  /* Ignore IANA's rather silly "Factory" zone; use GMT instead */
418  if (strcmp(resultbuf, "Factory") == 0)
419  return NULL;
420  return resultbuf;
421  }
422 
423  /*
424  * Couldn't find a match in the database, so next we try constructed zone
425  * names (like "PST8PDT").
426  *
427  * First we need to determine the names of the local standard and daylight
428  * zones. The idea here is to scan forward from today until we have seen
429  * both zones, if both are in use.
430  */
431  memset(std_zone_name, 0, sizeof(std_zone_name));
432  memset(dst_zone_name, 0, sizeof(dst_zone_name));
433  std_ofs = 0;
434 
435  tnow = time(NULL);
436 
437  /*
438  * Round back to a GMT midnight so results don't depend on local time of
439  * day
440  */
441  tnow -= (tnow % T_DAY);
442 
443  /*
444  * We have to look a little further ahead than one year, in case today is
445  * just past a DST boundary that falls earlier in the year than the next
446  * similar boundary. Arbitrarily scan up to 14 months.
447  */
448  for (t = tnow; t <= tnow + T_MONTH * 14; t += T_MONTH)
449  {
450  tm = localtime(&t);
451  if (!tm)
452  continue;
453  if (tm->tm_isdst < 0)
454  continue;
455  if (tm->tm_isdst == 0 && std_zone_name[0] == '\0')
456  {
457  /* found STD zone */
458  memset(cbuf, 0, sizeof(cbuf));
459  strftime(cbuf, sizeof(cbuf) - 1, "%Z", tm); /* zone abbr */
460  strcpy(std_zone_name, cbuf);
461  std_ofs = get_timezone_offset(tm);
462  }
463  if (tm->tm_isdst > 0 && dst_zone_name[0] == '\0')
464  {
465  /* found DST zone */
466  memset(cbuf, 0, sizeof(cbuf));
467  strftime(cbuf, sizeof(cbuf) - 1, "%Z", tm); /* zone abbr */
468  strcpy(dst_zone_name, cbuf);
469  }
470  /* Done if found both */
471  if (std_zone_name[0] && dst_zone_name[0])
472  break;
473  }
474 
475  /* We should have found a STD zone name by now... */
476  if (std_zone_name[0] == '\0')
477  {
478 #ifdef DEBUG_IDENTIFY_TIMEZONE
479  fprintf(stderr, "could not determine system time zone\n");
480 #endif
481  return NULL; /* go to GMT */
482  }
483 
484  /* If we found DST then try STD<ofs>DST */
485  if (dst_zone_name[0] != '\0')
486  {
487  snprintf(resultbuf, sizeof(resultbuf), "%s%d%s",
488  std_zone_name, -std_ofs / 3600, dst_zone_name);
489  if (score_timezone(resultbuf, &tt) > 0)
490  return resultbuf;
491  }
492 
493  /* Try just the STD timezone (works for GMT at least) */
494  strcpy(resultbuf, std_zone_name);
495  if (score_timezone(resultbuf, &tt) > 0)
496  return resultbuf;
497 
498  /* Try STD<ofs> */
499  snprintf(resultbuf, sizeof(resultbuf), "%s%d",
500  std_zone_name, -std_ofs / 3600);
501  if (score_timezone(resultbuf, &tt) > 0)
502  return resultbuf;
503 
504  /*
505  * Did not find the timezone. Fallback to use a GMT zone. Note that the
506  * IANA timezone database names the GMT-offset zones in POSIX style: plus
507  * is west of Greenwich. It's unfortunate that this is opposite of SQL
508  * conventions. Should we therefore change the names? Probably not...
509  */
510  snprintf(resultbuf, sizeof(resultbuf), "Etc/GMT%s%d",
511  (-std_ofs > 0) ? "+" : "", -std_ofs / 3600);
512 
513 #ifdef DEBUG_IDENTIFY_TIMEZONE
514  fprintf(stderr, "could not recognize system time zone, using \"%s\"\n",
515  resultbuf);
516 #endif
517  return resultbuf;
518 }
519 
520 /*
521  * Examine a system-provided symlink file to see if it tells us the timezone.
522  *
523  * Unfortunately, there is little standardization of how the system default
524  * timezone is determined in the absence of a TZ environment setting.
525  * But a common strategy is to create a symlink at a well-known place.
526  * If "linkname" identifies a readable symlink, and the tail of its contents
527  * matches a zone name we know, and the actual behavior of localtime() agrees
528  * with what we think that zone means, then we may use that zone name.
529  *
530  * We insist on a perfect behavioral match, which might not happen if the
531  * system has a different IANA database version than we do; but in that case
532  * it seems best to fall back to the brute-force search.
533  *
534  * linkname is the symlink file location to probe.
535  *
536  * tt tells about the system timezone behavior we need to match.
537  *
538  * If we successfully identify a zone name, store it in *bestzonename and
539  * return true; else return false. bestzonename must be a buffer of length
540  * TZ_STRLEN_MAX + 1.
541  */
542 static bool
543 check_system_link_file(const char *linkname, struct tztry *tt,
544  char *bestzonename)
545 {
546 #ifdef HAVE_READLINK
547  char link_target[MAXPGPATH];
548  int len;
549  const char *cur_name;
550 
551  /*
552  * Try to read the symlink. If not there, not a symlink, etc etc, just
553  * quietly fail; the precise reason needn't concern us.
554  */
555  len = readlink(linkname, link_target, sizeof(link_target));
556  if (len < 0 || len >= sizeof(link_target))
557  return false;
558  link_target[len] = '\0';
559 
560 #ifdef DEBUG_IDENTIFY_TIMEZONE
561  fprintf(stderr, "symbolic link \"%s\" contains \"%s\"\n",
562  linkname, link_target);
563 #endif
564 
565  /*
566  * The symlink is probably of the form "/path/to/zones/zone/name", or
567  * possibly it is a relative path. Nobody puts their zone DB directly in
568  * the root directory, so we can definitely skip the first component; but
569  * after that it's trial-and-error to identify which path component begins
570  * the zone name.
571  */
572  cur_name = link_target;
573  while (*cur_name)
574  {
575  /* Advance to next segment of path */
576  cur_name = strchr(cur_name + 1, '/');
577  if (cur_name == NULL)
578  break;
579  /* If there are consecutive slashes, skip all, as the kernel would */
580  do
581  {
582  cur_name++;
583  } while (*cur_name == '/');
584 
585  /*
586  * Test remainder of path to see if it is a matching zone name.
587  * Relative paths might contain ".."; we needn't bother testing if the
588  * first component is that. Also defend against overlength names.
589  */
590  if (*cur_name && *cur_name != '.' &&
591  strlen(cur_name) <= TZ_STRLEN_MAX &&
592  perfect_timezone_match(cur_name, tt))
593  {
594  /* Success! */
595  strcpy(bestzonename, cur_name);
596  return true;
597  }
598  }
599 
600  /* Couldn't extract a matching zone name */
601  return false;
602 #else
603  /* No symlinks? Forget it */
604  return false;
605 #endif
606 }
607 
608 /*
609  * Given a timezone name, determine whether it should be preferred over other
610  * names which are equally good matches. The output is arbitrary but we will
611  * use 0 for "neutral" default preference; larger values are more preferred.
612  */
613 static int
614 zone_name_pref(const char *zonename)
615 {
616  /*
617  * Prefer UTC over alternatives such as UCT. Also prefer Etc/UTC over
618  * Etc/UCT; but UTC is preferred to Etc/UTC.
619  */
620  if (strcmp(zonename, "UTC") == 0)
621  return 50;
622  if (strcmp(zonename, "Etc/UTC") == 0)
623  return 40;
624 
625  /*
626  * We don't want to pick "localtime" or "posixrules", unless we can find
627  * no other name for the prevailing zone. Those aren't real zone names.
628  */
629  if (strcmp(zonename, "localtime") == 0 ||
630  strcmp(zonename, "posixrules") == 0)
631  return -50;
632 
633  return 0;
634 }
635 
636 /*
637  * Recursively scan the timezone database looking for the best match to
638  * the system timezone behavior.
639  *
640  * tzdir points to a buffer of size MAXPGPATH. On entry, it holds the
641  * pathname of a directory containing TZ files. We internally modify it
642  * to hold pathnames of sub-directories and files, but must restore it
643  * to its original contents before exit.
644  *
645  * tzdirsub points to the part of tzdir that represents the subfile name
646  * (ie, tzdir + the original directory name length, plus one for the
647  * first added '/').
648  *
649  * tt tells about the system timezone behavior we need to match.
650  *
651  * *bestscore and *bestzonename on entry hold the best score found so far
652  * and the name of the best zone. We overwrite them if we find a better
653  * score. bestzonename must be a buffer of length TZ_STRLEN_MAX + 1.
654  */
655 static void
656 scan_available_timezones(char *tzdir, char *tzdirsub, struct tztry *tt,
657  int *bestscore, char *bestzonename)
658 {
659  int tzdir_orig_len = strlen(tzdir);
660  char **names;
661  char **namep;
662 
663  names = pgfnames(tzdir);
664  if (!names)
665  return;
666 
667  for (namep = names; *namep; namep++)
668  {
669  char *name = *namep;
670  struct stat statbuf;
671 
672  /* Ignore . and .., plus any other "hidden" files */
673  if (name[0] == '.')
674  continue;
675 
676  snprintf(tzdir + tzdir_orig_len, MAXPGPATH - tzdir_orig_len,
677  "/%s", name);
678 
679  if (stat(tzdir, &statbuf) != 0)
680  {
681 #ifdef DEBUG_IDENTIFY_TIMEZONE
682  fprintf(stderr, "could not stat \"%s\": %s\n",
683  tzdir, strerror(errno));
684 #endif
685  tzdir[tzdir_orig_len] = '\0';
686  continue;
687  }
688 
689  if (S_ISDIR(statbuf.st_mode))
690  {
691  /* Recurse into subdirectory */
692  scan_available_timezones(tzdir, tzdirsub, tt,
693  bestscore, bestzonename);
694  }
695  else
696  {
697  /* Load and test this file */
698  int score = score_timezone(tzdirsub, tt);
699 
700  if (score > *bestscore)
701  {
702  *bestscore = score;
703  strlcpy(bestzonename, tzdirsub, TZ_STRLEN_MAX + 1);
704  }
705  else if (score == *bestscore)
706  {
707  /* Consider how to break a tie */
708  int namepref = (zone_name_pref(tzdirsub) -
709  zone_name_pref(bestzonename));
710 
711  if (namepref > 0 ||
712  (namepref == 0 &&
713  (strlen(tzdirsub) < strlen(bestzonename) ||
714  (strlen(tzdirsub) == strlen(bestzonename) &&
715  strcmp(tzdirsub, bestzonename) < 0))))
716  strlcpy(bestzonename, tzdirsub, TZ_STRLEN_MAX + 1);
717  }
718  }
719 
720  /* Restore tzdir */
721  tzdir[tzdir_orig_len] = '\0';
722  }
723 
724  pgfnames_cleanup(names);
725 }
726 #else /* WIN32 */
727 
728 static const struct
729 {
730  const char *stdname; /* Windows name of standard timezone */
731  const char *dstname; /* Windows name of daylight timezone */
732  const char *pgtzname; /* Name of pgsql timezone to map to */
733 } win32_tzmap[] =
734 
735 {
736  /*
737  * This list was built from the contents of the registry at
738  * HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Time
739  * Zones on Windows 10 and Windows 7.
740  *
741  * The zones have been matched to IANA timezones by looking at the cities
742  * listed in the win32 display name (in the comment here) in most cases.
743  */
744  {
745  "Afghanistan Standard Time", "Afghanistan Daylight Time",
746  "Asia/Kabul"
747  }, /* (UTC+04:30) Kabul */
748  {
749  "Alaskan Standard Time", "Alaskan Daylight Time",
750  "US/Alaska"
751  }, /* (UTC-09:00) Alaska */
752  {
753  "Aleutian Standard Time", "Aleutian Daylight Time",
754  "US/Aleutan"
755  }, /* (UTC-10:00) Aleutian Islands */
756  {
757  "Altai Standard Time", "Altai Daylight Time",
758  "Asia/Barnaul"
759  }, /* (UTC+07:00) Barnaul, Gorno-Altaysk */
760  {
761  "Arab Standard Time", "Arab Daylight Time",
762  "Asia/Kuwait"
763  }, /* (UTC+03:00) Kuwait, Riyadh */
764  {
765  "Arabian Standard Time", "Arabian Daylight Time",
766  "Asia/Muscat"
767  }, /* (UTC+04:00) Abu Dhabi, Muscat */
768  {
769  "Arabic Standard Time", "Arabic Daylight Time",
770  "Asia/Baghdad"
771  }, /* (UTC+03:00) Baghdad */
772  {
773  "Argentina Standard Time", "Argentina Daylight Time",
774  "America/Buenos_Aires"
775  }, /* (UTC-03:00) City of Buenos Aires */
776  {
777  "Armenian Standard Time", "Armenian Daylight Time",
778  "Asia/Yerevan"
779  }, /* (UTC+04:00) Baku, Tbilisi, Yerevan */
780  {
781  "Astrakhan Standard Time", "Astrakhan Daylight Time",
782  "Europe/Astrakhan"
783  }, /* (UTC+04:00) Astrakhan, Ulyanovsk */
784  {
785  "Atlantic Standard Time", "Atlantic Daylight Time",
786  "Canada/Atlantic"
787  }, /* (UTC-04:00) Atlantic Time (Canada) */
788  {
789  "AUS Central Standard Time", "AUS Central Daylight Time",
790  "Australia/Darwin"
791  }, /* (UTC+09:30) Darwin */
792  {
793  "Aus Central W. Standard Time", "Aus Central W. Daylight Time",
794  "Australia/Eucla"
795  }, /* (UTC+08:45) Eucla */
796  {
797  "AUS Eastern Standard Time", "AUS Eastern Daylight Time",
798  "Australia/Canberra"
799  }, /* (UTC+10:00) Canberra, Melbourne, Sydney */
800  {
801  "Azerbaijan Standard Time", "Azerbaijan Daylight Time",
802  "Asia/Baku"
803  }, /* (UTC+04:00) Baku */
804  {
805  "Azores Standard Time", "Azores Daylight Time",
806  "Atlantic/Azores"
807  }, /* (UTC-01:00) Azores */
808  {
809  "Bahia Standard Time", "Bahia Daylight Time",
810  "America/Salvador"
811  }, /* (UTC-03:00) Salvador */
812  {
813  "Bangladesh Standard Time", "Bangladesh Daylight Time",
814  "Asia/Dhaka"
815  }, /* (UTC+06:00) Dhaka */
816  {
817  "Bougainville Standard Time", "Bougainville Daylight Time",
818  "Pacific/Bougainville"
819  }, /* (UTC+11:00) Bougainville Island */
820  {
821  "Belarus Standard Time", "Belarus Daylight Time",
822  "Europe/Minsk"
823  }, /* (UTC+03:00) Minsk */
824  {
825  "Cabo Verde Standard Time", "Cabo Verde Daylight Time",
826  "Atlantic/Cape_Verde"
827  }, /* (UTC-01:00) Cabo Verde Is. */
828  {
829  "Chatham Islands Standard Time", "Chatham Islands Daylight Time",
830  "Pacific/Chatham"
831  }, /* (UTC+12:45) Chatham Islands */
832  {
833  "Canada Central Standard Time", "Canada Central Daylight Time",
834  "Canada/Saskatchewan"
835  }, /* (UTC-06:00) Saskatchewan */
836  {
837  "Cape Verde Standard Time", "Cape Verde Daylight Time",
838  "Atlantic/Cape_Verde"
839  }, /* (UTC-01:00) Cape Verde Is. */
840  {
841  "Caucasus Standard Time", "Caucasus Daylight Time",
842  "Asia/Baku"
843  }, /* (UTC+04:00) Yerevan */
844  {
845  "Cen. Australia Standard Time", "Cen. Australia Daylight Time",
846  "Australia/Adelaide"
847  }, /* (UTC+09:30) Adelaide */
848  /* Central America (other than Mexico) generally does not observe DST */
849  {
850  "Central America Standard Time", "Central America Daylight Time",
851  "CST6"
852  }, /* (UTC-06:00) Central America */
853  {
854  "Central Asia Standard Time", "Central Asia Daylight Time",
855  "Asia/Dhaka"
856  }, /* (UTC+06:00) Astana */
857  {
858  "Central Brazilian Standard Time", "Central Brazilian Daylight Time",
859  "America/Cuiaba"
860  }, /* (UTC-04:00) Cuiaba */
861  {
862  "Central Europe Standard Time", "Central Europe Daylight Time",
863  "Europe/Belgrade"
864  }, /* (UTC+01:00) Belgrade, Bratislava, Budapest,
865  * Ljubljana, Prague */
866  {
867  "Central European Standard Time", "Central European Daylight Time",
868  "Europe/Sarajevo"
869  }, /* (UTC+01:00) Sarajevo, Skopje, Warsaw,
870  * Zagreb */
871  {
872  "Central Pacific Standard Time", "Central Pacific Daylight Time",
873  "Pacific/Noumea"
874  }, /* (UTC+11:00) Solomon Is., New Caledonia */
875  {
876  "Central Standard Time", "Central Daylight Time",
877  "US/Central"
878  }, /* (UTC-06:00) Central Time (US & Canada) */
879  {
880  "Central Standard Time (Mexico)", "Central Daylight Time (Mexico)",
881  "America/Mexico_City"
882  }, /* (UTC-06:00) Guadalajara, Mexico City,
883  * Monterrey */
884  {
885  "China Standard Time", "China Daylight Time",
886  "Asia/Hong_Kong"
887  }, /* (UTC+08:00) Beijing, Chongqing, Hong Kong,
888  * Urumqi */
889  {
890  "Cuba Standard Time", "Cuba Daylight Time",
891  "America/Havana"
892  }, /* (UTC-05:00) Havana */
893  {
894  "Dateline Standard Time", "Dateline Daylight Time",
895  "Etc/UTC+12"
896  }, /* (UTC-12:00) International Date Line West */
897  {
898  "E. Africa Standard Time", "E. Africa Daylight Time",
899  "Africa/Nairobi"
900  }, /* (UTC+03:00) Nairobi */
901  {
902  "E. Australia Standard Time", "E. Australia Daylight Time",
903  "Australia/Brisbane"
904  }, /* (UTC+10:00) Brisbane */
905  {
906  "E. Europe Standard Time", "E. Europe Daylight Time",
907  "Europe/Bucharest"
908  }, /* (UTC+02:00) E. Europe */
909  {
910  "E. South America Standard Time", "E. South America Daylight Time",
911  "America/Araguaina"
912  }, /* (UTC-03:00) Brasilia */
913  {
914  "Eastern Standard Time", "Eastern Daylight Time",
915  "US/Eastern"
916  }, /* (UTC-05:00) Eastern Time (US & Canada) */
917  {
918  "Eastern Standard Time (Mexico)", "Eastern Daylight Time (Mexico)",
919  "America/Mexico_City"
920  }, /* (UTC-05:00) Chetumal */
921  {
922  "Easter Island Standard Time", "Easter Island Daylight Time",
923  "Pacific/Easter"
924  }, /* (UTC-06:00) Easter Island */
925  {
926  "Egypt Standard Time", "Egypt Daylight Time",
927  "Africa/Cairo"
928  }, /* (UTC+02:00) Cairo */
929  {
930  "Ekaterinburg Standard Time (RTZ 4)", "Ekaterinburg Daylight Time",
931  "Asia/Yekaterinburg"
932  }, /* (UTC+05:00) Ekaterinburg */
933  {
934  "Fiji Standard Time", "Fiji Daylight Time",
935  "Pacific/Fiji"
936  }, /* (UTC+12:00) Fiji */
937  {
938  "FLE Standard Time", "FLE Daylight Time",
939  "Europe/Helsinki"
940  }, /* (UTC+02:00) Helsinki, Kyiv, Riga, Sofia,
941  * Tallinn, Vilnius */
942  {
943  "Georgian Standard Time", "Georgian Daylight Time",
944  "Asia/Tbilisi"
945  }, /* (UTC+04:00) Tbilisi */
946  {
947  "GMT Standard Time", "GMT Daylight Time",
948  "Europe/London"
949  }, /* (UTC) Dublin, Edinburgh, Lisbon, London */
950  {
951  "Greenland Standard Time", "Greenland Daylight Time",
952  "America/Godthab"
953  }, /* (UTC-03:00) Greenland */
954  {
955  "Greenwich Standard Time", "Greenwich Daylight Time",
956  "Africa/Casablanca"
957  }, /* (UTC) Monrovia, Reykjavik */
958  {
959  "GTB Standard Time", "GTB Daylight Time",
960  "Europe/Athens"
961  }, /* (UTC+02:00) Athens, Bucharest */
962  {
963  "Haiti Standard Time", "Haiti Daylight Time",
964  "US/Eastern"
965  }, /* (UTC-05:00) Haiti */
966  {
967  "Hawaiian Standard Time", "Hawaiian Daylight Time",
968  "US/Hawaii"
969  }, /* (UTC-10:00) Hawaii */
970  {
971  "India Standard Time", "India Daylight Time",
972  "Asia/Calcutta"
973  }, /* (UTC+05:30) Chennai, Kolkata, Mumbai, New
974  * Delhi */
975  {
976  "Iran Standard Time", "Iran Daylight Time",
977  "Asia/Tehran"
978  }, /* (UTC+03:30) Tehran */
979  {
980  "Jerusalem Standard Time", "Jerusalem Daylight Time",
981  "Asia/Jerusalem"
982  }, /* (UTC+02:00) Jerusalem */
983  {
984  "Jordan Standard Time", "Jordan Daylight Time",
985  "Asia/Amman"
986  }, /* (UTC+02:00) Amman */
987  {
988  "Kamchatka Standard Time", "Kamchatka Daylight Time",
989  "Asia/Kamchatka"
990  }, /* (UTC+12:00) Petropavlovsk-Kamchatsky - Old */
991  {
992  "Korea Standard Time", "Korea Daylight Time",
993  "Asia/Seoul"
994  }, /* (UTC+09:00) Seoul */
995  {
996  "Libya Standard Time", "Libya Daylight Time",
997  "Africa/Tripoli"
998  }, /* (UTC+02:00) Tripoli */
999  {
1000  "Line Islands Standard Time", "Line Islands Daylight Time",
1001  "Pacific/Kiritimati"
1002  }, /* (UTC+14:00) Kiritimati Island */
1003  {
1004  "Lord Howe Standard Time", "Lord Howe Daylight Time",
1005  "Australia/Lord_Howe"
1006  }, /* (UTC+10:30) Lord Howe Island */
1007  {
1008  "Magadan Standard Time", "Magadan Daylight Time",
1009  "Asia/Magadan"
1010  }, /* (UTC+10:00) Magadan */
1011  {
1012  "Marquesas Standard Time", "Marquesas Daylight Time",
1013  "Pacific/Marquesas"
1014  }, /* (UTC-09:30) Marquesas Islands */
1015  {
1016  "Mauritius Standard Time", "Mauritius Daylight Time",
1017  "Indian/Mauritius"
1018  }, /* (UTC+04:00) Port Louis */
1019  {
1020  "Mexico Standard Time", "Mexico Daylight Time",
1021  "America/Mexico_City"
1022  }, /* (UTC-06:00) Guadalajara, Mexico City,
1023  * Monterrey */
1024  {
1025  "Mexico Standard Time 2", "Mexico Daylight Time 2",
1026  "America/Chihuahua"
1027  }, /* (UTC-07:00) Chihuahua, La Paz, Mazatlan */
1028  {
1029  "Mid-Atlantic Standard Time", "Mid-Atlantic Daylight Time",
1030  "Atlantic/South_Georgia"
1031  }, /* (UTC-02:00) Mid-Atlantic - Old */
1032  {
1033  "Middle East Standard Time", "Middle East Daylight Time",
1034  "Asia/Beirut"
1035  }, /* (UTC+02:00) Beirut */
1036  {
1037  "Montevideo Standard Time", "Montevideo Daylight Time",
1038  "America/Montevideo"
1039  }, /* (UTC-03:00) Montevideo */
1040  {
1041  "Morocco Standard Time", "Morocco Daylight Time",
1042  "Africa/Casablanca"
1043  }, /* (UTC) Casablanca */
1044  {
1045  "Mountain Standard Time", "Mountain Daylight Time",
1046  "US/Mountain"
1047  }, /* (UTC-07:00) Mountain Time (US & Canada) */
1048  {
1049  "Mountain Standard Time (Mexico)", "Mountain Daylight Time (Mexico)",
1050  "America/Chihuahua"
1051  }, /* (UTC-07:00) Chihuahua, La Paz, Mazatlan */
1052  {
1053  "Myanmar Standard Time", "Myanmar Daylight Time",
1054  "Asia/Rangoon"
1055  }, /* (UTC+06:30) Yangon (Rangoon) */
1056  {
1057  "N. Central Asia Standard Time", "N. Central Asia Daylight Time",
1058  "Asia/Novosibirsk"
1059  }, /* (UTC+06:00) Novosibirsk (RTZ 5) */
1060  {
1061  "Namibia Standard Time", "Namibia Daylight Time",
1062  "Africa/Windhoek"
1063  }, /* (UTC+01:00) Windhoek */
1064  {
1065  "Nepal Standard Time", "Nepal Daylight Time",
1066  "Asia/Katmandu"
1067  }, /* (UTC+05:45) Kathmandu */
1068  {
1069  "New Zealand Standard Time", "New Zealand Daylight Time",
1070  "Pacific/Auckland"
1071  }, /* (UTC+12:00) Auckland, Wellington */
1072  {
1073  "Newfoundland Standard Time", "Newfoundland Daylight Time",
1074  "Canada/Newfoundland"
1075  }, /* (UTC-03:30) Newfoundland */
1076  {
1077  "Norfolk Standard Time", "Norfolk Daylight Time",
1078  "Pacific/Norfolk"
1079  }, /* (UTC+11:00) Norfolk Island */
1080  {
1081  "North Asia East Standard Time", "North Asia East Daylight Time",
1082  "Asia/Irkutsk"
1083  }, /* (UTC+08:00) Irkutsk, Ulaan Bataar */
1084  {
1085  "North Asia Standard Time", "North Asia Daylight Time",
1086  "Asia/Krasnoyarsk"
1087  }, /* (UTC+07:00) Krasnoyarsk */
1088  {
1089  "North Korea Standard Time", "North Korea Daylight Time",
1090  "Asia/Pyongyang"
1091  }, /* (UTC+08:30) Pyongyang */
1092  {
1093  "Pacific SA Standard Time", "Pacific SA Daylight Time",
1094  "America/Santiago"
1095  }, /* (UTC-03:00) Santiago */
1096  {
1097  "Pacific Standard Time", "Pacific Daylight Time",
1098  "US/Pacific"
1099  }, /* (UTC-08:00) Pacific Time (US & Canada) */
1100  {
1101  "Pacific Standard Time (Mexico)", "Pacific Daylight Time (Mexico)",
1102  "America/Tijuana"
1103  }, /* (UTC-08:00) Baja California */
1104  {
1105  "Pakistan Standard Time", "Pakistan Daylight Time",
1106  "Asia/Karachi"
1107  }, /* (UTC+05:00) Islamabad, Karachi */
1108  {
1109  "Paraguay Standard Time", "Paraguay Daylight Time",
1110  "America/Asuncion"
1111  }, /* (UTC-04:00) Asuncion */
1112  {
1113  "Romance Standard Time", "Romance Daylight Time",
1114  "Europe/Brussels"
1115  }, /* (UTC+01:00) Brussels, Copenhagen, Madrid,
1116  * Paris */
1117  {
1118  "Russia TZ 1 Standard Time", "Russia TZ 1 Daylight Time",
1119  "Europe/Kaliningrad"
1120  }, /* (UTC+02:00) Kaliningrad (RTZ 1) */
1121  {
1122  "Russia TZ 2 Standard Time", "Russia TZ 2 Daylight Time",
1123  "Europe/Moscow"
1124  }, /* (UTC+03:00) Moscow, St. Petersburg,
1125  * Volgograd (RTZ 2) */
1126  {
1127  "Russia TZ 3 Standard Time", "Russia TZ 3 Daylight Time",
1128  "Europe/Samara"
1129  }, /* (UTC+04:00) Izhevsk, Samara (RTZ 3) */
1130  {
1131  "Russia TZ 4 Standard Time", "Russia TZ 4 Daylight Time",
1132  "Asia/Yekaterinburg"
1133  }, /* (UTC+05:00) Ekaterinburg (RTZ 4) */
1134  {
1135  "Russia TZ 5 Standard Time", "Russia TZ 5 Daylight Time",
1136  "Asia/Novosibirsk"
1137  }, /* (UTC+06:00) Novosibirsk (RTZ 5) */
1138  {
1139  "Russia TZ 6 Standard Time", "Russia TZ 6 Daylight Time",
1140  "Asia/Krasnoyarsk"
1141  }, /* (UTC+07:00) Krasnoyarsk (RTZ 6) */
1142  {
1143  "Russia TZ 7 Standard Time", "Russia TZ 7 Daylight Time",
1144  "Asia/Irkutsk"
1145  }, /* (UTC+08:00) Irkutsk (RTZ 7) */
1146  {
1147  "Russia TZ 8 Standard Time", "Russia TZ 8 Daylight Time",
1148  "Asia/Yakutsk"
1149  }, /* (UTC+09:00) Yakutsk (RTZ 8) */
1150  {
1151  "Russia TZ 9 Standard Time", "Russia TZ 9 Daylight Time",
1152  "Asia/Vladivostok"
1153  }, /* (UTC+10:00) Vladivostok, Magadan (RTZ 9) */
1154  {
1155  "Russia TZ 10 Standard Time", "Russia TZ 10 Daylight Time",
1156  "Asia/Magadan"
1157  }, /* (UTC+11:00) Chokurdakh (RTZ 10) */
1158  {
1159  "Russia TZ 11 Standard Time", "Russia TZ 11 Daylight Time",
1160  "Asia/Anadyr"
1161  }, /* (UTC+12:00) Anadyr,
1162  * Petropavlovsk-Kamchatsky (RTZ 11) */
1163  {
1164  "Russian Standard Time", "Russian Daylight Time",
1165  "Europe/Moscow"
1166  }, /* (UTC+03:00) Moscow, St. Petersburg,
1167  * Volgograd */
1168  {
1169  "SA Eastern Standard Time", "SA Eastern Daylight Time",
1170  "America/Buenos_Aires"
1171  }, /* (UTC-03:00) Cayenne, Fortaleza */
1172  {
1173  "SA Pacific Standard Time", "SA Pacific Daylight Time",
1174  "America/Bogota"
1175  }, /* (UTC-05:00) Bogota, Lima, Quito, Rio Branco */
1176  {
1177  "SA Western Standard Time", "SA Western Daylight Time",
1178  "America/Caracas"
1179  }, /* (UTC-04:00) Georgetown, La Paz, Manaus, San
1180  * Juan */
1181  {
1182  "Saint Pierre Standard Time", "Saint Pierre Daylight Time",
1183  "America/Miquelon"
1184  }, /* (UTC-03:00) Saint Pierre and Miquelon */
1185  {
1186  "Samoa Standard Time", "Samoa Daylight Time",
1187  "Pacific/Samoa"
1188  }, /* (UTC+13:00) Samoa */
1189  {
1190  "SE Asia Standard Time", "SE Asia Daylight Time",
1191  "Asia/Bangkok"
1192  }, /* (UTC+07:00) Bangkok, Hanoi, Jakarta */
1193  {
1194  "Malay Peninsula Standard Time", "Malay Peninsula Daylight Time",
1195  "Asia/Kuala_Lumpur"
1196  }, /* (UTC+08:00) Kuala Lumpur, Singapore */
1197  {
1198  "Sakhalin Standard Time", "Sakhalin Daylight Time",
1199  "Asia/Sakhalin"
1200  }, /* (UTC+11:00) Sakhalin */
1201  {
1202  "South Africa Standard Time", "South Africa Daylight Time",
1203  "Africa/Harare"
1204  }, /* (UTC+02:00) Harare, Pretoria */
1205  {
1206  "Sri Lanka Standard Time", "Sri Lanka Daylight Time",
1207  "Asia/Colombo"
1208  }, /* (UTC+05:30) Sri Jayawardenepura */
1209  {
1210  "Syria Standard Time", "Syria Daylight Time",
1211  "Asia/Damascus"
1212  }, /* (UTC+02:00) Damascus */
1213  {
1214  "Taipei Standard Time", "Taipei Daylight Time",
1215  "Asia/Taipei"
1216  }, /* (UTC+08:00) Taipei */
1217  {
1218  "Tasmania Standard Time", "Tasmania Daylight Time",
1219  "Australia/Hobart"
1220  }, /* (UTC+10:00) Hobart */
1221  {
1222  "Tocantins Standard Time", "Tocantins Daylight Time",
1223  "America/Araguaina"
1224  }, /* (UTC-03:00) Araguaina */
1225  {
1226  "Tokyo Standard Time", "Tokyo Daylight Time",
1227  "Asia/Tokyo"
1228  }, /* (UTC+09:00) Osaka, Sapporo, Tokyo */
1229  {
1230  "Tonga Standard Time", "Tonga Daylight Time",
1231  "Pacific/Tongatapu"
1232  }, /* (UTC+13:00) Nuku'alofa */
1233  {
1234  "Tomsk Standard Time", "Tomsk Daylight Time",
1235  "Asia/Tomsk"
1236  }, /* (UTC+07:00) Tomsk */
1237  {
1238  "Transbaikal Standard Time", "Transbaikal Daylight Time",
1239  "Asia/Chita"
1240  }, /* (UTC+09:00) Chita */
1241  {
1242  "Turkey Standard Time", "Turkey Daylight Time",
1243  "Europe/Istanbul"
1244  }, /* (UTC+02:00) Istanbul */
1245  {
1246  "Turks and Caicos Standard Time", "Turks and Caicos Daylight Time",
1247  "America/Grand_Turk"
1248  }, /* (UTC-04:00) Turks and Caicos */
1249  {
1250  "Ulaanbaatar Standard Time", "Ulaanbaatar Daylight Time",
1251  "Asia/Ulaanbaatar",
1252  }, /* (UTC+08:00) Ulaanbaatar */
1253  {
1254  "US Eastern Standard Time", "US Eastern Daylight Time",
1255  "US/Eastern"
1256  }, /* (UTC-05:00) Indiana (East) */
1257  {
1258  "US Mountain Standard Time", "US Mountain Daylight Time",
1259  "US/Arizona"
1260  }, /* (UTC-07:00) Arizona */
1261  {
1262  "Coordinated Universal Time", "Coordinated Universal Time",
1263  "UTC"
1264  }, /* (UTC) Coordinated Universal Time */
1265  {
1266  "UTC+12", "UTC+12",
1267  "Etc/GMT+12"
1268  }, /* (UTC+12:00) Coordinated Universal Time+12 */
1269  {
1270  "UTC-02", "UTC-02",
1271  "Etc/GMT-02"
1272  }, /* (UTC-02:00) Coordinated Universal Time-02 */
1273  {
1274  "UTC-08", "UTC-08",
1275  "Etc/GMT-08"
1276  }, /* (UTC-08:00) Coordinated Universal Time-08 */
1277  {
1278  "UTC-09", "UTC-09",
1279  "Etc/GMT-09"
1280  }, /* (UTC-09:00) Coordinated Universal Time-09 */
1281  {
1282  "UTC-11", "UTC-11",
1283  "Etc/GMT-11"
1284  }, /* (UTC-11:00) Coordinated Universal Time-11 */
1285  {
1286  "Venezuela Standard Time", "Venezuela Daylight Time",
1287  "America/Caracas",
1288  }, /* (UTC-04:30) Caracas */
1289  {
1290  "Vladivostok Standard Time", "Vladivostok Daylight Time",
1291  "Asia/Vladivostok"
1292  }, /* (UTC+10:00) Vladivostok (RTZ 9) */
1293  {
1294  "W. Australia Standard Time", "W. Australia Daylight Time",
1295  "Australia/Perth"
1296  }, /* (UTC+08:00) Perth */
1297 #ifdef NOT_USED
1298  /* Could not find a match for this one (just a guess). Excluded for now. */
1299  {
1300  "W. Central Africa Standard Time", "W. Central Africa Daylight Time",
1301  "WAT"
1302  }, /* (UTC+01:00) West Central Africa */
1303 #endif
1304  {
1305  "W. Europe Standard Time", "W. Europe Daylight Time",
1306  "CET"
1307  }, /* (UTC+01:00) Amsterdam, Berlin, Bern, Rome,
1308  * Stockholm, Vienna */
1309  {
1310  "W. Mongolia Standard Time", "W. Mongolia Daylight Time",
1311  "Asia/Hovd"
1312  }, /* (UTC+07:00) Hovd */
1313  {
1314  "West Asia Standard Time", "West Asia Daylight Time",
1315  "Asia/Karachi"
1316  }, /* (UTC+05:00) Ashgabat, Tashkent */
1317  {
1318  "West Bank Gaza Standard Time", "West Bank Gaza Daylight Time",
1319  "Asia/Gaza"
1320  }, /* (UTC+02:00) Gaza, Hebron */
1321  {
1322  "West Pacific Standard Time", "West Pacific Daylight Time",
1323  "Pacific/Guam"
1324  }, /* (UTC+10:00) Guam, Port Moresby */
1325  {
1326  "Yakutsk Standard Time", "Yakutsk Daylight Time",
1327  "Asia/Yakutsk"
1328  }, /* (UTC+09:00) Yakutsk */
1329  {
1330  NULL, NULL, NULL
1331  }
1332 };
1333 
1334 static const char *
1336 {
1337  int i;
1338  char tzname[128];
1339  char localtzname[256];
1340  time_t t = time(NULL);
1341  struct tm *tm = localtime(&t);
1342  HKEY rootKey;
1343  int idx;
1344 
1345  if (!tm)
1346  {
1347 #ifdef DEBUG_IDENTIFY_TIMEZONE
1348  fprintf(stderr, "could not identify system time zone: localtime() failed\n");
1349 #endif
1350  return NULL; /* go to GMT */
1351  }
1352 
1353  memset(tzname, 0, sizeof(tzname));
1354  strftime(tzname, sizeof(tzname) - 1, "%Z", tm);
1355 
1356  for (i = 0; win32_tzmap[i].stdname != NULL; i++)
1357  {
1358  if (strcmp(tzname, win32_tzmap[i].stdname) == 0 ||
1359  strcmp(tzname, win32_tzmap[i].dstname) == 0)
1360  {
1361 #ifdef DEBUG_IDENTIFY_TIMEZONE
1362  fprintf(stderr, "TZ \"%s\" matches system time zone \"%s\"\n",
1363  win32_tzmap[i].pgtzname, tzname);
1364 #endif
1365  return win32_tzmap[i].pgtzname;
1366  }
1367  }
1368 
1369  /*
1370  * Localized Windows versions return localized names for the timezone.
1371  * Scan the registry to find the English name, and then try matching
1372  * against our table again.
1373  */
1374  memset(localtzname, 0, sizeof(localtzname));
1375  if (RegOpenKeyEx(HKEY_LOCAL_MACHINE,
1376  "SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\Time Zones",
1377  0,
1378  KEY_READ,
1379  &rootKey) != ERROR_SUCCESS)
1380  {
1381 #ifdef DEBUG_IDENTIFY_TIMEZONE
1382  fprintf(stderr, "could not open registry key to identify system time zone: error code %lu\n",
1383  GetLastError());
1384 #endif
1385  return NULL; /* go to GMT */
1386  }
1387 
1388  for (idx = 0;; idx++)
1389  {
1390  char keyname[256];
1391  char zonename[256];
1392  DWORD namesize;
1393  FILETIME lastwrite;
1394  HKEY key;
1395  LONG r;
1396 
1397  memset(keyname, 0, sizeof(keyname));
1398  namesize = sizeof(keyname);
1399  if ((r = RegEnumKeyEx(rootKey,
1400  idx,
1401  keyname,
1402  &namesize,
1403  NULL,
1404  NULL,
1405  NULL,
1406  &lastwrite)) != ERROR_SUCCESS)
1407  {
1408  if (r == ERROR_NO_MORE_ITEMS)
1409  break;
1410 #ifdef DEBUG_IDENTIFY_TIMEZONE
1411  fprintf(stderr, "could not enumerate registry subkeys to identify system time zone: %d\n",
1412  (int) r);
1413 #endif
1414  break;
1415  }
1416 
1417  if ((r = RegOpenKeyEx(rootKey, keyname, 0, KEY_READ, &key)) != ERROR_SUCCESS)
1418  {
1419 #ifdef DEBUG_IDENTIFY_TIMEZONE
1420  fprintf(stderr, "could not open registry subkey to identify system time zone: %d\n",
1421  (int) r);
1422 #endif
1423  break;
1424  }
1425 
1426  memset(zonename, 0, sizeof(zonename));
1427  namesize = sizeof(zonename);
1428  if ((r = RegQueryValueEx(key, "Std", NULL, NULL, (unsigned char *) zonename, &namesize)) != ERROR_SUCCESS)
1429  {
1430 #ifdef DEBUG_IDENTIFY_TIMEZONE
1431  fprintf(stderr, "could not query value for key \"std\" to identify system time zone \"%s\": %d\n",
1432  keyname, (int) r);
1433 #endif
1434  RegCloseKey(key);
1435  continue; /* Proceed to look at the next timezone */
1436  }
1437  if (strcmp(tzname, zonename) == 0)
1438  {
1439  /* Matched zone */
1440  strcpy(localtzname, keyname);
1441  RegCloseKey(key);
1442  break;
1443  }
1444  memset(zonename, 0, sizeof(zonename));
1445  namesize = sizeof(zonename);
1446  if ((r = RegQueryValueEx(key, "Dlt", NULL, NULL, (unsigned char *) zonename, &namesize)) != ERROR_SUCCESS)
1447  {
1448 #ifdef DEBUG_IDENTIFY_TIMEZONE
1449  fprintf(stderr, "could not query value for key \"dlt\" to identify system time zone \"%s\": %d\n",
1450  keyname, (int) r);
1451 #endif
1452  RegCloseKey(key);
1453  continue; /* Proceed to look at the next timezone */
1454  }
1455  if (strcmp(tzname, zonename) == 0)
1456  {
1457  /* Matched DST zone */
1458  strcpy(localtzname, keyname);
1459  RegCloseKey(key);
1460  break;
1461  }
1462 
1463  RegCloseKey(key);
1464  }
1465 
1466  RegCloseKey(rootKey);
1467 
1468  if (localtzname[0])
1469  {
1470  /* Found a localized name, so scan for that one too */
1471  for (i = 0; win32_tzmap[i].stdname != NULL; i++)
1472  {
1473  if (strcmp(localtzname, win32_tzmap[i].stdname) == 0 ||
1474  strcmp(localtzname, win32_tzmap[i].dstname) == 0)
1475  {
1476 #ifdef DEBUG_IDENTIFY_TIMEZONE
1477  fprintf(stderr, "TZ \"%s\" matches localized system time zone \"%s\" (\"%s\")\n",
1478  win32_tzmap[i].pgtzname, tzname, localtzname);
1479 #endif
1480  return win32_tzmap[i].pgtzname;
1481  }
1482  }
1483  }
1484 
1485 #ifdef DEBUG_IDENTIFY_TIMEZONE
1486  fprintf(stderr, "could not find a match for system time zone \"%s\"\n",
1487  tzname);
1488 #endif
1489  return NULL; /* go to GMT */
1490 }
1491 #endif /* WIN32 */
1492 
1493 
1494 /*
1495  * Return true if the given zone name is valid and is an "acceptable" zone.
1496  */
1497 static bool
1498 validate_zone(const char *tzname)
1499 {
1500  pg_tz *tz;
1501 
1502  if (!tzname || !tzname[0])
1503  return false;
1504 
1505  tz = pg_load_tz(tzname);
1506  if (!tz)
1507  return false;
1508 
1509  if (!pg_tz_acceptable(tz))
1510  return false;
1511 
1512  return true;
1513 }
1514 
1515 /*
1516  * Identify a suitable default timezone setting based on the environment.
1517  *
1518  * The installation share_path must be passed in, as that is the default
1519  * location for the timezone database directory.
1520  *
1521  * We first look to the TZ environment variable. If not found or not
1522  * recognized by our own code, we see if we can identify the timezone
1523  * from the behavior of the system timezone library. When all else fails,
1524  * return NULL, indicating that we should default to GMT.
1525  */
1526 const char *
1528 {
1529  const char *tzname;
1530 
1531  /* Initialize timezone directory path, if needed */
1532 #ifndef SYSTEMTZDIR
1533  snprintf(tzdirpath, sizeof(tzdirpath), "%s/timezone", share_path);
1534 #endif
1535 
1536  /* Check TZ environment variable */
1537  tzname = getenv("TZ");
1538  if (validate_zone(tzname))
1539  return tzname;
1540 
1541  /* Nope, so try to identify the system timezone */
1542  tzname = identify_system_timezone();
1543  if (validate_zone(tzname))
1544  return tzname;
1545 
1546  return NULL;
1547 }
#define T_DAY
Definition: findtimezone.c:152
const char * select_default_timezone(const char *share_path)
char ** pgfnames(const char *path)
Definition: pgfnames.c:37
static bool validate_zone(const char *tzname)
int64 pg_time_t
Definition: pgtime.h:23
int tm_wday
Definition: pgtime.h:33
static void scan_available_timezones(char *tzdir, char *tzdirsub, struct tztry *tt, int *bestscore, char *bestzonename)
Definition: findtimezone.c:656
int tm_isdst
Definition: pgtime.h:35
int tzload(const char *name, char *canonname, struct state *sp, bool doextend)
Definition: localtime.c:588
int tm_hour
Definition: pgtime.h:29
#define TIMEZONE_GLOBAL
Definition: port.h:226
#define T_MONTH
Definition: findtimezone.c:154
time_t test_times[MAX_TEST_TIMES]
Definition: findtimezone.c:161
Datum idx(PG_FUNCTION_ARGS)
Definition: _int_op.c:263
Definition: pgtime.h:25
static pg_tz * pg_load_tz(const char *name)
Definition: findtimezone.c:91
#define fprintf
Definition: port.h:196
static const char * pg_TZDIR(void)
Definition: findtimezone.c:37
#define PG_BINARY
Definition: c.h:1222
static int zone_name_pref(const char *zonename)
Definition: findtimezone.c:614
static char * share_path
Definition: initdb.c:120
static struct pg_tm tm
Definition: localtime.c:108
#define TZ_STRLEN_MAX
Definition: pgtime.h:44
#define MAXPGPATH
static bool compare_tm(struct tm *s, struct pg_tm *p)
Definition: findtimezone.c:206
static bool perfect_timezone_match(const char *tzname, struct tztry *tt)
Definition: findtimezone.c:319
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Definition: pgtime.h:30
int tm_mon
Definition: pgtime.h:31
#define readlink(path, buf, size)
Definition: win32_port.h:222
int n_test_times
Definition: findtimezone.c:160
static int get_timezone_offset(struct tm *tm)
Definition: findtimezone.c:175
static time_t build_time_t(int year, int month, int day)
Definition: findtimezone.c:190
const char * tm_zone
Definition: pgtime.h:37
bool tzparse(const char *name, struct state *sp, bool lastditch)
Definition: localtime.c:938
#define T_WEEK
Definition: findtimezone.c:153
#define stat(a, b)
Definition: win32_port.h:255
static int score_timezone(const char *tzname, struct tztry *tt)
Definition: findtimezone.c:233
static char tzdirpath[MAXPGPATH]
Definition: findtimezone.c:27
bool pg_tz_acceptable(pg_tz *tz)
Definition: localtime.c:1905
struct state state
Definition: pgtz.h:69
Definition: pgtz.h:65
size_t strlcpy(char *dst, const char *src, size_t siz)
Definition: strlcpy.c:45
void pgfnames_cleanup(char **filenames)
Definition: pgfnames.c:86
#define strerror
Definition: port.h:205
char TZname[TZ_STRLEN_MAX+1]
Definition: pgtz.h:68
static bool check_system_link_file(const char *linkname, struct tztry *tt, char *bestzonename)
Definition: findtimezone.c:543
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Definition: localtime.c:1375
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Definition: encode.c:521
#define S_ISDIR(m)
Definition: win32_port.h:296
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Definition: pgtime.h:32
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static const char * identify_system_timezone(void)
Definition: findtimezone.c:330
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Definition: findtimezone.c:65
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Definition: pgtime.h:34
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Definition: pgtime.h:27
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Definition: port.h:192
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Definition: pgtime.h:28
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Definition: findtimezone.c:156