PostgreSQL Source Code git master
Data Structures | Macros | Functions | Variables
findtimezone.c File Reference
#include "postgres_fe.h"
#include <fcntl.h>
#include <sys/stat.h>
#include <time.h>
#include <unistd.h>
#include "pgtz.h"
Include dependency graph for findtimezone.c:

Go to the source code of this file.

Data Structures

struct   tztry
 

Macros

#define  T_DAY   ((time_t) (60*60*24))
 
#define  T_WEEK   ((time_t) (60*60*24*7))
 
#define  T_MONTH   ((time_t) (60*60*24*31))
 
#define  MAX_TEST_TIMES   (52*100) /* 100 years */
 

Functions

const char *  select_default_timezone (const char *share_path)
 
static const char *  pg_TZDIR (void)
 
int  pg_open_tzfile (const char *name, char *canonname)
 
static pg_tz *  pg_load_tz (const char *name)
 
static bool  check_system_link_file (const char *linkname, struct tztry *tt, char *bestzonename)
 
static void  scan_available_timezones (char *tzdir, char *tzdirsub, struct tztry *tt, int *bestscore, char *bestzonename)
 
static int  get_timezone_offset (struct tm *tm)
 
static time_t  build_time_t (int year, int month, int day)
 
static bool  compare_tm (struct tm *s, struct pg_tm *p)
 
static int  score_timezone (const char *tzname, struct tztry *tt)
 
static bool  perfect_timezone_match (const char *tzname, struct tztry *tt)
 
static const char *  identify_system_timezone (void)
 
static int  zone_name_pref (const char *zonename)
 
static bool  validate_zone (const char *tzname)
 

Variables

static char  tzdirpath [MAXPGPATH]
 

Macro Definition Documentation

◆ MAX_TEST_TIMES

#define MAX_TEST_TIMES   (52*100) /* 100 years */

Definition at line 156 of file findtimezone.c.

◆ T_DAY

#define T_DAY   ((time_t) (60*60*24))

Definition at line 152 of file findtimezone.c.

◆ T_MONTH

#define T_MONTH   ((time_t) (60*60*24*31))

Definition at line 154 of file findtimezone.c.

◆ T_WEEK

#define T_WEEK   ((time_t) (60*60*24*7))

Definition at line 153 of file findtimezone.c.

Function Documentation

◆ build_time_t()

static time_t build_time_t ( int  year,
int  month,
int  day 
)
static

Definition at line 190 of file findtimezone.c.

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 tm.tm_isdst = -1;
199
200 return mktime(&tm);
201}
static struct pg_tm tm
Definition: localtime.c:104
int tm_mday
Definition: pgtime.h:39
int tm_mon
Definition: pgtime.h:40
int tm_isdst
Definition: pgtime.h:44
int tm_year
Definition: pgtime.h:41

References tm, pg_tm::tm_isdst, pg_tm::tm_mday, pg_tm::tm_mon, and pg_tm::tm_year.

Referenced by identify_system_timezone().

◆ check_system_link_file()

static bool check_system_link_file ( const char *  linkname,
struct tztry *  tt,
char *  bestzonename 
)
static

Definition at line 544 of file findtimezone.c.

546{
547#ifdef HAVE_READLINK
548 char link_target[MAXPGPATH];
549 int len;
550 const char *cur_name;
551
552 /*
553 * Try to read the symlink. If not there, not a symlink, etc etc, just
554 * quietly fail; the precise reason needn't concern us.
555 */
556 len = readlink(linkname, link_target, sizeof(link_target));
557 if (len < 0 || len >= sizeof(link_target))
558 return false;
559 link_target[len] = '0円';
560
561#ifdef DEBUG_IDENTIFY_TIMEZONE
562 fprintf(stderr, "symbolic link \"%s\" contains \"%s\"\n",
563 linkname, link_target);
564#endif
565
566 /*
567 * The symlink is probably of the form "/path/to/zones/zone/name", or
568 * possibly it is a relative path. Nobody puts their zone DB directly in
569 * the root directory, so we can definitely skip the first component; but
570 * after that it's trial-and-error to identify which path component begins
571 * the zone name.
572 */
573 cur_name = link_target;
574 while (*cur_name)
575 {
576 /* Advance to next segment of path */
577 cur_name = strchr(cur_name + 1, '/');
578 if (cur_name == NULL)
579 break;
580 /* If there are consecutive slashes, skip all, as the kernel would */
581 do
582 {
583 cur_name++;
584 } while (*cur_name == '/');
585
586 /*
587 * Test remainder of path to see if it is a matching zone name.
588 * Relative paths might contain ".."; we needn't bother testing if the
589 * first component is that. Also defend against overlength names.
590 */
591 if (*cur_name && *cur_name != '.' &&
592 strlen(cur_name) <= TZ_STRLEN_MAX &&
593 perfect_timezone_match(cur_name, tt))
594 {
595 /* Success! */
596 strcpy(bestzonename, cur_name);
597 return true;
598 }
599 }
600
601 /* Couldn't extract a matching zone name */
602 return false;
603#else
604 /* No symlinks? Forget it */
605 return false;
606#endif
607}
#define fprintf(file, fmt, msg)
Definition: cubescan.l:21
static bool perfect_timezone_match(const char *tzname, struct tztry *tt)
Definition: findtimezone.c:320
#define MAXPGPATH
const void size_t len
#define TZ_STRLEN_MAX
Definition: pgtime.h:54
#define readlink(path, buf, size)
Definition: win32_port.h:226

References fprintf, len, MAXPGPATH, perfect_timezone_match(), readlink, and TZ_STRLEN_MAX.

Referenced by identify_system_timezone().

◆ compare_tm()

static bool compare_tm ( struct tm *  s,
struct pg_tm *  p 
)
static

Definition at line 207 of file findtimezone.c.

208{
209 if (s->tm_sec != p->tm_sec ||
210 s->tm_min != p->tm_min ||
211 s->tm_hour != p->tm_hour ||
212 s->tm_mday != p->tm_mday ||
213 s->tm_mon != p->tm_mon ||
214 s->tm_year != p->tm_year ||
215 s->tm_wday != p->tm_wday ||
216 s->tm_yday != p->tm_yday ||
217 s->tm_isdst != p->tm_isdst)
218 return false;
219 return true;
220}
int tm_hour
Definition: pgtime.h:38
int tm_min
Definition: pgtime.h:37
int tm_yday
Definition: pgtime.h:43
int tm_wday
Definition: pgtime.h:42
int tm_sec
Definition: pgtime.h:36

References pg_tm::tm_hour, pg_tm::tm_isdst, pg_tm::tm_mday, pg_tm::tm_min, pg_tm::tm_mon, pg_tm::tm_sec, pg_tm::tm_wday, pg_tm::tm_yday, and pg_tm::tm_year.

Referenced by score_timezone().

◆ get_timezone_offset()

static int get_timezone_offset ( struct tm *  tm )
static

Definition at line 175 of file findtimezone.c.

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}
#define TIMEZONE_GLOBAL
Definition: port.h:269
long int tm_gmtoff
Definition: pgtime.h:45

References TIMEZONE_GLOBAL, tm, and pg_tm::tm_gmtoff.

Referenced by identify_system_timezone().

◆ identify_system_timezone()

static const char * identify_system_timezone ( void  )
static

Definition at line 331 of file findtimezone.c.

332{
333 static char resultbuf[TZ_STRLEN_MAX + 1];
334 time_t tnow;
335 time_t t;
336 struct tztry tt;
337 struct tm *tm;
338 int thisyear;
339 int bestscore;
340 char tmptzdir[MAXPGPATH];
341 int std_ofs;
342 char std_zone_name[TZ_STRLEN_MAX + 1],
343 dst_zone_name[TZ_STRLEN_MAX + 1];
344 char cbuf[TZ_STRLEN_MAX + 1];
345
346 /* Initialize OS timezone library */
347 tzset();
348
349 /*
350 * Set up the list of dates to be probed to see how well our timezone
351 * matches the system zone. We first probe January and July of the
352 * current year; this serves to quickly eliminate the vast majority of the
353 * TZ database entries. If those dates match, we probe every week for 100
354 * years backwards from the current July. (Weekly resolution is good
355 * enough to identify DST transition rules, since everybody switches on
356 * Sundays.) This is sufficient to cover most of the Unix time_t range,
357 * and we don't want to look further than that since many systems won't
358 * have sane TZ behavior further back anyway. The further back the zone
359 * matches, the better we score it. This may seem like a rather random
360 * way of doing things, but experience has shown that system-supplied
361 * timezone definitions are likely to have DST behavior that is right for
362 * the recent past and not so accurate further back. Scoring in this way
363 * allows us to recognize zones that have some commonality with the IANA
364 * database, without insisting on exact match. (Note: we probe Thursdays,
365 * not Sundays, to avoid triggering DST-transition bugs in localtime
366 * itself.)
367 */
368 tnow = time(NULL);
369 tm = localtime(&tnow);
370 if (!tm)
371 return NULL; /* give up if localtime is broken... */
372 thisyear = tm->tm_year + 1900;
373
374 t = build_time_t(thisyear, 1, 15);
375
376 /*
377 * Round back to GMT midnight Thursday. This depends on the knowledge
378 * that the time_t origin is Thu Jan 01 1970. (With a different origin
379 * we'd be probing some other day of the week, but it wouldn't matter
380 * anyway unless localtime() had DST-transition bugs.)
381 */
382 t -= (t % T_WEEK);
383
384 tt.n_test_times = 0;
385 tt.test_times[tt.n_test_times++] = t;
386
387 t = build_time_t(thisyear, 7, 15);
388 t -= (t % T_WEEK);
389
390 tt.test_times[tt.n_test_times++] = t;
391
392 while (tt.n_test_times < MAX_TEST_TIMES)
393 {
394 t -= T_WEEK;
395 tt.test_times[tt.n_test_times++] = t;
396 }
397
398 /*
399 * Try to avoid the brute-force search by seeing if we can recognize the
400 * system's timezone setting directly.
401 *
402 * Currently we just check /etc/localtime; there are other conventions for
403 * this, but that seems to be the only one used on enough platforms to be
404 * worth troubling over.
405 */
406 if (check_system_link_file("/etc/localtime", &tt, resultbuf))
407 return resultbuf;
408
409 /* No luck, so search for the best-matching timezone file */
410 strlcpy(tmptzdir, pg_TZDIR(), sizeof(tmptzdir));
411 bestscore = -1;
412 resultbuf[0] = '0円';
413 scan_available_timezones(tmptzdir, tmptzdir + strlen(tmptzdir) + 1,
414 &tt,
415 &bestscore, resultbuf);
416 if (bestscore > 0)
417 {
418 /* Ignore IANA's rather silly "Factory" zone; use GMT instead */
419 if (strcmp(resultbuf, "Factory") == 0)
420 return NULL;
421 return resultbuf;
422 }
423
424 /*
425 * Couldn't find a match in the database, so next we try constructed zone
426 * names (like "PST8PDT").
427 *
428 * First we need to determine the names of the local standard and daylight
429 * zones. The idea here is to scan forward from today until we have seen
430 * both zones, if both are in use.
431 */
432 memset(std_zone_name, 0, sizeof(std_zone_name));
433 memset(dst_zone_name, 0, sizeof(dst_zone_name));
434 std_ofs = 0;
435
436 tnow = time(NULL);
437
438 /*
439 * Round back to a GMT midnight so results don't depend on local time of
440 * day
441 */
442 tnow -= (tnow % T_DAY);
443
444 /*
445 * We have to look a little further ahead than one year, in case today is
446 * just past a DST boundary that falls earlier in the year than the next
447 * similar boundary. Arbitrarily scan up to 14 months.
448 */
449 for (t = tnow; t <= tnow + T_MONTH * 14; t += T_MONTH)
450 {
451 tm = localtime(&t);
452 if (!tm)
453 continue;
454 if (tm->tm_isdst < 0)
455 continue;
456 if (tm->tm_isdst == 0 && std_zone_name[0] == '0円')
457 {
458 /* found STD zone */
459 memset(cbuf, 0, sizeof(cbuf));
460 strftime(cbuf, sizeof(cbuf) - 1, "%Z", tm); /* zone abbr */
461 strcpy(std_zone_name, cbuf);
462 std_ofs = get_timezone_offset(tm);
463 }
464 if (tm->tm_isdst > 0 && dst_zone_name[0] == '0円')
465 {
466 /* found DST zone */
467 memset(cbuf, 0, sizeof(cbuf));
468 strftime(cbuf, sizeof(cbuf) - 1, "%Z", tm); /* zone abbr */
469 strcpy(dst_zone_name, cbuf);
470 }
471 /* Done if found both */
472 if (std_zone_name[0] && dst_zone_name[0])
473 break;
474 }
475
476 /* We should have found a STD zone name by now... */
477 if (std_zone_name[0] == '0円')
478 {
479#ifdef DEBUG_IDENTIFY_TIMEZONE
480 fprintf(stderr, "could not determine system time zone\n");
481#endif
482 return NULL; /* go to GMT */
483 }
484
485 /* If we found DST then try STD<ofs>DST */
486 if (dst_zone_name[0] != '0円')
487 {
488 snprintf(resultbuf, sizeof(resultbuf), "%s%d%s",
489 std_zone_name, -std_ofs / 3600, dst_zone_name);
490 if (score_timezone(resultbuf, &tt) > 0)
491 return resultbuf;
492 }
493
494 /* Try just the STD timezone (works for GMT at least) */
495 strcpy(resultbuf, std_zone_name);
496 if (score_timezone(resultbuf, &tt) > 0)
497 return resultbuf;
498
499 /* Try STD<ofs> */
500 snprintf(resultbuf, sizeof(resultbuf), "%s%d",
501 std_zone_name, -std_ofs / 3600);
502 if (score_timezone(resultbuf, &tt) > 0)
503 return resultbuf;
504
505 /*
506 * Did not find the timezone. Fallback to use a GMT zone. Note that the
507 * IANA timezone database names the GMT-offset zones in POSIX style: plus
508 * is west of Greenwich. It's unfortunate that this is opposite of SQL
509 * conventions. Should we therefore change the names? Probably not...
510 */
511 snprintf(resultbuf, sizeof(resultbuf), "Etc/GMT%s%d",
512 (-std_ofs > 0) ? "+" : "", -std_ofs / 3600);
513
514#ifdef DEBUG_IDENTIFY_TIMEZONE
515 fprintf(stderr, "could not recognize system time zone, using \"%s\"\n",
516 resultbuf);
517#endif
518 return resultbuf;
519}
static void scan_available_timezones(char *tzdir, char *tzdirsub, struct tztry *tt, int *bestscore, char *bestzonename)
Definition: findtimezone.c:657
#define T_DAY
Definition: findtimezone.c:152
static const char * pg_TZDIR(void)
Definition: findtimezone.c:37
#define T_MONTH
Definition: findtimezone.c:154
static time_t build_time_t(int year, int month, int day)
Definition: findtimezone.c:190
#define T_WEEK
Definition: findtimezone.c:153
static int get_timezone_offset(struct tm *tm)
Definition: findtimezone.c:175
static int score_timezone(const char *tzname, struct tztry *tt)
Definition: findtimezone.c:234
static bool check_system_link_file(const char *linkname, struct tztry *tt, char *bestzonename)
Definition: findtimezone.c:544
#define MAX_TEST_TIMES
Definition: findtimezone.c:156
#define snprintf
Definition: port.h:239
size_t strlcpy(char *dst, const char *src, size_t siz)
Definition: strlcpy.c:45

References build_time_t(), check_system_link_file(), fprintf, get_timezone_offset(), MAX_TEST_TIMES, MAXPGPATH, tztry::n_test_times, pg_TZDIR(), scan_available_timezones(), score_timezone(), snprintf, strlcpy(), T_DAY, T_MONTH, T_WEEK, tztry::test_times, tm, pg_tm::tm_isdst, pg_tm::tm_year, and TZ_STRLEN_MAX.

Referenced by select_default_timezone().

◆ perfect_timezone_match()

static bool perfect_timezone_match ( const char *  tzname,
struct tztry *  tt 
)
static

Definition at line 320 of file findtimezone.c.

321{
322 return (score_timezone(tzname, tt) == tt->n_test_times);
323}
int n_test_times
Definition: findtimezone.c:160

References tztry::n_test_times, and score_timezone().

Referenced by check_system_link_file().

◆ pg_load_tz()

static pg_tz * pg_load_tz ( const char *  name )
static

Definition at line 91 of file findtimezone.c.

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}
int tzload(const char *name, char *canonname, struct state *sp, bool doextend)
Definition: localtime.c:586
bool tzparse(const char *name, struct state *sp, bool lastditch)
Definition: localtime.c:936
Definition: pgtz.h:66
char TZname[TZ_STRLEN_MAX+1]
Definition: pgtz.h:68
struct state state
Definition: pgtz.h:69
const char * name

References name, pg_tz::state, TZ_STRLEN_MAX, tzload(), pg_tz::TZname, and tzparse().

Referenced by score_timezone(), and validate_zone().

◆ pg_open_tzfile()

int pg_open_tzfile ( const char *  name,
char *  canonname 
)

Definition at line 65 of file findtimezone.c.

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}
#define PG_BINARY
Definition: c.h:1272

References MAXPGPATH, name, PG_BINARY, pg_TZDIR(), strlcpy(), and TZ_STRLEN_MAX.

Referenced by tzloadbody().

◆ pg_TZDIR()

static const char * pg_TZDIR ( void  )
static

Definition at line 37 of file findtimezone.c.

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}
static char tzdirpath[MAXPGPATH]
Definition: findtimezone.c:27

References tzdirpath.

Referenced by identify_system_timezone(), and pg_open_tzfile().

◆ scan_available_timezones()

static void scan_available_timezones ( char *  tzdir,
char *  tzdirsub,
struct tztry *  tt,
int *  bestscore,
char *  bestzonename 
)
static

Definition at line 657 of file findtimezone.c.

659{
660 int tzdir_orig_len = strlen(tzdir);
661 char **names;
662 char **namep;
663
664 names = pgfnames(tzdir);
665 if (!names)
666 return;
667
668 for (namep = names; *namep; namep++)
669 {
670 char *name = *namep;
671 struct stat statbuf;
672
673 /* Ignore . and .., plus any other "hidden" files */
674 if (name[0] == '.')
675 continue;
676
677 snprintf(tzdir + tzdir_orig_len, MAXPGPATH - tzdir_orig_len,
678 "/%s", name);
679
680 if (stat(tzdir, &statbuf) != 0)
681 {
682#ifdef DEBUG_IDENTIFY_TIMEZONE
683 fprintf(stderr, "could not stat \"%s\": %m\n",
684 tzdir);
685#endif
686 tzdir[tzdir_orig_len] = '0円';
687 continue;
688 }
689
690 if (S_ISDIR(statbuf.st_mode))
691 {
692 /* Recurse into subdirectory */
693 scan_available_timezones(tzdir, tzdirsub, tt,
694 bestscore, bestzonename);
695 }
696 else
697 {
698 /* Load and test this file */
699 int score = score_timezone(tzdirsub, tt);
700
701 if (score > *bestscore)
702 {
703 *bestscore = score;
704 strlcpy(bestzonename, tzdirsub, TZ_STRLEN_MAX + 1);
705 }
706 else if (score == *bestscore)
707 {
708 /* Consider how to break a tie */
709 int namepref = (zone_name_pref(tzdirsub) -
710 zone_name_pref(bestzonename));
711
712 if (namepref > 0 ||
713 (namepref == 0 &&
714 (strlen(tzdirsub) < strlen(bestzonename) ||
715 (strlen(tzdirsub) == strlen(bestzonename) &&
716 strcmp(tzdirsub, bestzonename) < 0))))
717 strlcpy(bestzonename, tzdirsub, TZ_STRLEN_MAX + 1);
718 }
719 }
720
721 /* Restore tzdir */
722 tzdir[tzdir_orig_len] = '0円';
723 }
724
725 pgfnames_cleanup(names);
726}
static int zone_name_pref(const char *zonename)
Definition: findtimezone.c:615
void pgfnames_cleanup(char **filenames)
Definition: pgfnames.c:86
char ** pgfnames(const char *path)
Definition: pgfnames.c:37
Definition: win32_port.h:255
#define stat
Definition: win32_port.h:274
#define S_ISDIR(m)
Definition: win32_port.h:315

References fprintf, MAXPGPATH, name, pgfnames(), pgfnames_cleanup(), S_ISDIR, scan_available_timezones(), score_timezone(), snprintf, stat::st_mode, stat, strlcpy(), TZ_STRLEN_MAX, and zone_name_pref().

Referenced by identify_system_timezone(), and scan_available_timezones().

◆ score_timezone()

static int score_timezone ( const char *  tzname,
struct tztry *  tt 
)
static

Definition at line 234 of file findtimezone.c.

235{
236 int i;
237 pg_time_t pgtt;
238 struct tm *systm;
239 struct pg_tm *pgtm;
240 char cbuf[TZ_STRLEN_MAX + 1];
241 pg_tz *tz;
242
243 /* Load timezone definition */
244 tz = pg_load_tz(tzname);
245 if (!tz)
246 return -1; /* unrecognized zone name */
247
248 /* Reject if leap seconds involved */
249 if (!pg_tz_acceptable(tz))
250 {
251#ifdef DEBUG_IDENTIFY_TIMEZONE
252 fprintf(stderr, "Reject TZ \"%s\": uses leap seconds\n", tzname);
253#endif
254 return -1;
255 }
256
257 /* Check for match at all the test times */
258 for (i = 0; i < tt->n_test_times; i++)
259 {
260 pgtt = (pg_time_t) (tt->test_times[i]);
261 pgtm = pg_localtime(&pgtt, tz);
262 if (!pgtm)
263 return -1; /* probably shouldn't happen */
264 systm = localtime(&(tt->test_times[i]));
265 if (!systm)
266 {
267#ifdef DEBUG_IDENTIFY_TIMEZONE
268 fprintf(stderr, "TZ \"%s\" scores %d: at %ld %04d-%02d-%02d %02d:%02d:%02d %s, system had no data\n",
269 tzname, i, (long) pgtt,
270 pgtm->tm_year + 1900, pgtm->tm_mon + 1, pgtm->tm_mday,
271 pgtm->tm_hour, pgtm->tm_min, pgtm->tm_sec,
272 pgtm->tm_isdst ? "dst" : "std");
273#endif
274 return i;
275 }
276 if (!compare_tm(systm, pgtm))
277 {
278#ifdef DEBUG_IDENTIFY_TIMEZONE
279 fprintf(stderr, "TZ \"%s\" scores %d: at %ld %04d-%02d-%02d %02d:%02d:%02d %s versus %04d-%02d-%02d %02d:%02d:%02d %s\n",
280 tzname, i, (long) pgtt,
281 pgtm->tm_year + 1900, pgtm->tm_mon + 1, pgtm->tm_mday,
282 pgtm->tm_hour, pgtm->tm_min, pgtm->tm_sec,
283 pgtm->tm_isdst ? "dst" : "std",
284 systm->tm_year + 1900, systm->tm_mon + 1, systm->tm_mday,
285 systm->tm_hour, systm->tm_min, systm->tm_sec,
286 systm->tm_isdst ? "dst" : "std");
287#endif
288 return i;
289 }
290 if (systm->tm_isdst >= 0)
291 {
292 /* Check match of zone names, too */
293 if (pgtm->tm_zone == NULL)
294 return -1; /* probably shouldn't happen */
295 memset(cbuf, 0, sizeof(cbuf));
296 strftime(cbuf, sizeof(cbuf) - 1, "%Z", systm); /* zone abbr */
297 if (strcmp(cbuf, pgtm->tm_zone) != 0)
298 {
299#ifdef DEBUG_IDENTIFY_TIMEZONE
300 fprintf(stderr, "TZ \"%s\" scores %d: at %ld \"%s\" versus \"%s\"\n",
301 tzname, i, (long) pgtt,
302 pgtm->tm_zone, cbuf);
303#endif
304 return i;
305 }
306 }
307 }
308
309#ifdef DEBUG_IDENTIFY_TIMEZONE
310 fprintf(stderr, "TZ \"%s\" gets max score %d\n", tzname, i);
311#endif
312
313 return i;
314}
static pg_tz * pg_load_tz(const char *name)
Definition: findtimezone.c:91
static bool compare_tm(struct tm *s, struct pg_tm *p)
Definition: findtimezone.c:207
i
int i
Definition: isn.c:77
bool pg_tz_acceptable(pg_tz *tz)
Definition: localtime.c:2004
int64 pg_time_t
Definition: pgtime.h:23
struct pg_tm * pg_localtime(const pg_time_t *timep, const pg_tz *tz)
Definition: localtime.c:1344
Definition: pgtime.h:35
const char * tm_zone
Definition: pgtime.h:46
time_t test_times[MAX_TEST_TIMES]
Definition: findtimezone.c:161

References compare_tm(), fprintf, i, tztry::n_test_times, pg_load_tz(), pg_localtime(), pg_tz_acceptable(), tztry::test_times, tm, pg_tm::tm_hour, pg_tm::tm_isdst, pg_tm::tm_mday, pg_tm::tm_min, pg_tm::tm_mon, pg_tm::tm_sec, pg_tm::tm_year, pg_tm::tm_zone, and TZ_STRLEN_MAX.

Referenced by identify_system_timezone(), perfect_timezone_match(), and scan_available_timezones().

◆ select_default_timezone()

const char * select_default_timezone ( const char *  share_path )

Definition at line 1757 of file findtimezone.c.

1758{
1759 const char *tzname;
1760
1761 /* Initialize timezone directory path, if needed */
1762#ifndef SYSTEMTZDIR
1763 snprintf(tzdirpath, sizeof(tzdirpath), "%s/timezone", share_path);
1764#endif
1765
1766 /* Check TZ environment variable */
1767 tzname = getenv("TZ");
1768 if (validate_zone(tzname))
1769 return tzname;
1770
1771 /* Nope, so try to identify the system timezone */
1772 tzname = identify_system_timezone();
1773 if (validate_zone(tzname))
1774 return tzname;
1775
1776 return NULL;
1777}
static const char * identify_system_timezone(void)
Definition: findtimezone.c:331
static bool validate_zone(const char *tzname)
Definition: findtimezone.c:1728
static char * share_path
Definition: initdb.c:135

References identify_system_timezone(), share_path, snprintf, tzdirpath, and validate_zone().

Referenced by test_config_settings().

◆ validate_zone()

static bool validate_zone ( const char *  tzname )
static

Definition at line 1728 of file findtimezone.c.

1729{
1730 pg_tz *tz;
1731
1732 if (!tzname || !tzname[0])
1733 return false;
1734
1735 tz = pg_load_tz(tzname);
1736 if (!tz)
1737 return false;
1738
1739 if (!pg_tz_acceptable(tz))
1740 return false;
1741
1742 return true;
1743}

References pg_load_tz(), and pg_tz_acceptable().

Referenced by select_default_timezone().

◆ zone_name_pref()

static int zone_name_pref ( const char *  zonename )
static

Definition at line 615 of file findtimezone.c.

616{
617 /*
618 * Prefer UTC over alternatives such as UCT. Also prefer Etc/UTC over
619 * Etc/UCT; but UTC is preferred to Etc/UTC.
620 */
621 if (strcmp(zonename, "UTC") == 0)
622 return 50;
623 if (strcmp(zonename, "Etc/UTC") == 0)
624 return 40;
625
626 /*
627 * We don't want to pick "localtime" or "posixrules", unless we can find
628 * no other name for the prevailing zone. Those aren't real zone names.
629 */
630 if (strcmp(zonename, "localtime") == 0 ||
631 strcmp(zonename, "posixrules") == 0)
632 return -50;
633
634 return 0;
635}

Referenced by scan_available_timezones().

Variable Documentation

◆ tzdirpath

char tzdirpath[MAXPGPATH]
static

Definition at line 27 of file findtimezone.c.

Referenced by pg_TZDIR(), and select_default_timezone().

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