diff options
Diffstat (limited to 'src/backend/commands/variable.c')
| -rw-r--r-- | src/backend/commands/variable.c | 257 |
1 files changed, 36 insertions, 221 deletions
diff --git a/src/backend/commands/variable.c b/src/backend/commands/variable.c index f83ce51baca..45ed717951e 100644 --- a/src/backend/commands/variable.c +++ b/src/backend/commands/variable.c @@ -9,7 +9,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/commands/variable.c,v 1.94 2004/05/07 00:24:57 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/commands/variable.c,v 1.95 2004/05/21 05:07:57 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -17,13 +17,13 @@ #include "postgres.h" #include <ctype.h> -#include <time.h> #include "access/xact.h" #include "catalog/pg_shadow.h" #include "commands/variable.h" #include "miscadmin.h" #include "parser/scansup.h" +#include "pgtime.h" #include "utils/builtins.h" #include "utils/guc.h" #include "utils/syscache.h" @@ -31,17 +31,6 @@ #include "mb/pg_wchar.h" /* - * Some systems have tzname[] but don't declare it in <time.h>. Use this - * to duplicate the test in AC_STRUCT_TIMEZONE. - */ -#ifdef HAVE_TZNAME -#ifndef tzname /* For SGI. */ -extern char *tzname[]; -#endif -#endif - - -/* * DATESTYLE */ @@ -238,149 +227,6 @@ assign_datestyle(const char *value, bool doit, GucSource source) */ /* - * Storage for TZ env var is allocated with an arbitrary size of 64 bytes. - */ -#define TZBUF_LEN 64 - -static char tzbuf[TZBUF_LEN]; - -/* - * First time through, we remember the original environment TZ value, if any. - */ -static bool have_saved_tz = false; -static char orig_tzbuf[TZBUF_LEN]; - -/* - * Convenience subroutine for assigning the value of TZ - */ -static void -set_tz(const char *tz) -{ - strcpy(tzbuf, "TZ="); - strncpy(tzbuf + 3, tz, sizeof(tzbuf) - 4); - if (putenv(tzbuf) != 0) /* shouldn't happen? */ - elog(LOG, "could not set TZ environment variable"); - tzset(); -} - -/* - * Remove any value of TZ we have established - * - * Note: this leaves us with *no* value of TZ in the environment, and - * is therefore only appropriate for reverting to that state, not for - * reverting to a state where TZ was set to something else. - */ -static void -clear_tz(void) -{ - /* - * unsetenv() works fine, but is BSD, not POSIX, and is not available - * under Solaris, among others. Apparently putenv() called as below - * clears the process-specific environment variables. Other - * reasonable arguments to putenv() (e.g. "TZ=", "TZ", "") result in a - * core dump (under Linux anyway). - thomas 1998-01-26 - */ - if (tzbuf[0] == 'T') - { - strcpy(tzbuf, "="); - if (putenv(tzbuf) != 0) - elog(LOG, "could not clear TZ environment variable"); - tzset(); - } -} - -/* - * Check whether tzset() succeeded - * - * Unfortunately, tzset doesn't offer any well-defined way to detect that the - * value of TZ was bad. Often it will just select UTC (GMT) as the effective - * timezone. We use the following heuristics: - * - * If tzname[1] is a nonempty string, *or* the global timezone variable is - * not zero, then tzset must have recognized the TZ value as something - * different from UTC. Return true. - * - * Otherwise, check to see if the TZ name is a known spelling of "UTC" - * (ie, appears in our internal tables as a timezone equivalent to UTC). - * If so, accept it. - * - * This will reject nonstandard spellings of UTC unless tzset() chose to - * set tzname[1] as well as tzname[0]. The glibc version of tzset() will - * do so, but on other systems we may be tightening the spec a little. - * - * Another problem is that on some platforms (eg HPUX), if tzset thinks the - * input is bogus then it will adopt the system default timezone, which we - * really can't tell is not the intended translation of the input. - * - * Still, it beats failing to detect bad TZ names at all, and a silent - * failure mode of adopting the system-wide default is much better than - * a silent failure mode of adopting UTC. - * - * NB: this must NOT ereport(ERROR). The caller must get control back so that - * it can restore the old value of TZ if we don't like the new one. - */ -static bool -tzset_succeeded(const char *tz) -{ - char *tztmp; - int tzval; - - /* - * Check first set of heuristics to say that tzset definitely worked. - */ -#ifdef HAVE_TZNAME - if (tzname[1] && tzname[1][0] != '\0') - return true; -#endif - if (TIMEZONE_GLOBAL != 0) - return true; - - /* - * Check for known spellings of "UTC". Note we must downcase the - * input before passing it to DecodePosixTimezone(). - */ - tztmp = downcase_truncate_identifier(tz, strlen(tz), false); - if (DecodePosixTimezone(tztmp, &tzval) == 0) - if (tzval == 0) - return true; - - return false; -} - -/* - * Check whether timezone is acceptable. - * - * What we are doing here is checking for leap-second-aware timekeeping. - * We need to reject such TZ settings because they'll wreak havoc with our - * date/time arithmetic. - * - * NB: this must NOT ereport(ERROR). The caller must get control back so that - * it can restore the old value of TZ if we don't like the new one. - */ -static bool -tz_acceptable(void) -{ - struct tm tt; - time_t time2000; - - /* - * To detect leap-second timekeeping, compute the time_t value for - * local midnight, 2000-01-01. Insist that this be a multiple of 60; - * any partial-minute offset has to be due to leap seconds. - */ - MemSet(&tt, 0, sizeof(tt)); - tt.tm_year = 100; - tt.tm_mon = 0; - tt.tm_mday = 1; - tt.tm_isdst = -1; - time2000 = mktime(&tt); - if ((time2000 % 60) != 0) - return false; - - return true; -} - -/* * assign_timezone: GUC assign_hook for timezone */ const char * @@ -391,21 +237,6 @@ assign_timezone(const char *value, bool doit, GucSource source) double hours; /* - * On first call, see if there is a TZ in the original environment. - * Save that value permanently. - */ - if (!have_saved_tz) - { - char *orig_tz = getenv("TZ"); - - if (orig_tz) - StrNCpy(orig_tzbuf, orig_tz, sizeof(orig_tzbuf)); - else - orig_tzbuf[0] = '\0'; - have_saved_tz = true; - } - - /* * Check for INTERVAL 'foo' */ if (pg_strncasecmp(value, "interval", 8) == 0) @@ -476,36 +307,21 @@ assign_timezone(const char *value, bool doit, GucSource source) { /* * UNKNOWN is the value shown as the "default" for TimeZone in - * guc.c. We interpret it as meaning the original TZ - * inherited from the environment. Note that if there is an - * original TZ setting, we will return that rather than + * guc.c. We interpret it as being a complete no-op; we don't + * change the timezone setting. Note that if there is a known + * timezone setting, we will return that name rather than * UNKNOWN as the canonical spelling. + * + * During GUC initialization, since the timezone library isn't + * set up yet, pg_get_current_timezone will return NULL and we + * will leave the setting as UNKNOWN. If this isn't overridden + * from the config file then pg_timezone_initialize() will + * eventually select a default value from the environment. */ - if (doit) - { - bool ok; - - /* Revert to original setting of TZ, whatever it was */ - if (orig_tzbuf[0]) - { - set_tz(orig_tzbuf); - ok = tzset_succeeded(orig_tzbuf) && tz_acceptable(); - } - else - { - clear_tz(); - ok = tz_acceptable(); - } + const char *curzone = pg_get_current_timezone(); - if (ok) - HasCTZSet = false; - else - { - /* Bogus, so force UTC (equivalent to INTERVAL 0) */ - CTimeZone = 0; - HasCTZSet = true; - } - } + if (curzone) + value = curzone; } else { @@ -514,22 +330,22 @@ assign_timezone(const char *value, bool doit, GucSource source) * * We have to actually apply the change before we can have any * hope of checking it. So, save the old value in case we - * have to back out. Note that it's possible the old setting - * is in tzbuf, so we'd better copy it. + * have to back out. We have to copy since pg_get_current_timezone + * returns a pointer to its static state. */ - char save_tzbuf[TZBUF_LEN]; + const char *cur_tz; char *save_tz; bool known, acceptable; - save_tz = getenv("TZ"); - if (save_tz) - StrNCpy(save_tzbuf, save_tz, sizeof(save_tzbuf)); - - set_tz(value); + cur_tz = pg_get_current_timezone(); + if (cur_tz) + save_tz = pstrdup(cur_tz); + else + save_tz = NULL; - known = tzset_succeeded(value); - acceptable = tz_acceptable(); + known = pg_tzset(value); + acceptable = known ? tz_acceptable() : false; if (doit && known && acceptable) { @@ -544,9 +360,9 @@ assign_timezone(const char *value, bool doit, GucSource source) * a fixed offset, we still are. */ if (save_tz) - set_tz(save_tzbuf); - else - clear_tz(); + pg_tzset(save_tz); + else /* TZ library not initialized yet */ + select_default_timezone(); /* Complain if it was bad */ if (!known) { @@ -578,17 +394,16 @@ assign_timezone(const char *value, bool doit, GucSource source) /* * Prepare the canonical string to return. GUC wants it malloc'd. */ - result = (char *) malloc(sizeof(tzbuf)); - if (!result) - return NULL; - if (HasCTZSet) - snprintf(result, sizeof(tzbuf), "%.5f", + { + result = (char *) malloc(64); + if (!result) + return NULL; + snprintf(result, 64, "%.5f", (double) (-CTimeZone) / 3600.0); - else if (tzbuf[0] == 'T') - strcpy(result, tzbuf + 3); + } else - strcpy(result, "UNKNOWN"); + result = strdup(value); return result; } @@ -599,7 +414,7 @@ assign_timezone(const char *value, bool doit, GucSource source) const char * show_timezone(void) { - char *tzn; + const char *tzn; if (HasCTZSet) { @@ -612,7 +427,7 @@ show_timezone(void) IntervalPGetDatum(&interval))); } else - tzn = getenv("TZ"); + tzn = pg_get_current_timezone(); if (tzn != NULL) return tzn; |