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https://frontier.innolan.net/rainlance/amiga-tz.git
synced 2025-11-24 05:35:28 +00:00
Make the library thread-safe if THREAD_SAFE is defined.
* localtime.c [THREAD_SAFE]: Include pthread.h. (VOLATILE): New macro. (locallock) [THREAD_SAFE]: New static var. (lock, unlock): New functions. (lcl_is_set, gmt_is_set): Now VOLATILE. (tzsetwall): Move cleaned-up guts to new function tzsetwall_unlocked, for which this is now merely a locking wrapper. (tzset): Similarly, for new function tzset_unlocked. (localsub): Don't set tzname here; that's not thread-safe. This change can lose information on hosts without TM_ZONE, but there is no reliable way to fix that in a thread-safe way. (localtime_tzset): New function, which does proper locking. (localtime, localtime_r): Use it. (gmtsub): Do not worry about initializing gmtptr, as that's now the caller's responsibility. (gmtime): Reimplement in terms of gmtime_r. (timegm): Reimplement in terms of timeoff. (gmtime_r, offtime, mktime, timeoff, time2posix, posix2time): Lock at start and unlock at end. * Makefile, NEWS: Document this.
This commit is contained in:
Paul Eggert
250
localtime.c
250
localtime.c
@ -16,6 +16,18 @@
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#include "tzfile.h"
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#include "fcntl.h"
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#if THREAD_SAFE
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# include <pthread.h>
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# define VOLATILE volatile
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static pthread_mutex_t locallock = PTHREAD_MUTEX_INITIALIZER;
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static int lock(void) { return pthread_mutex_lock(&locallock); }
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static void unlock(void) { pthread_mutex_unlock(&locallock); }
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#else
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# define VOLATILE
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static int lock(void) { return 0; }
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static void unlock(void) { }
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#endif
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#ifndef TZ_ABBR_MAX_LEN
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#define TZ_ABBR_MAX_LEN 16
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#endif /* !defined TZ_ABBR_MAX_LEN */
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@ -154,8 +166,8 @@ static struct state gmtmem;
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#endif /* !defined TZ_STRLEN_MAX */
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static char lcl_TZname[TZ_STRLEN_MAX + 1];
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static int lcl_is_set;
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static int gmt_is_set;
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static int VOLATILE lcl_is_set;
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static int VOLATILE gmt_is_set;
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char * tzname[2] = {
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(char *) wildabbr,
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@ -1139,6 +1151,21 @@ gmtload(struct state *const sp)
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(void) tzparse(gmt, sp, TRUE);
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}
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static void
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tzsetwall_unlocked(void)
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{
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if (lcl_is_set < 0)
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return;
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#ifdef ALL_STATE
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if (! lclptr)
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lclptr = malloc(sizeof *lclptr);
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#endif
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if (lclptr && tzload(NULL, lclptr, TRUE) != 0)
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gmtload(lclptr);
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settzname();
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lcl_is_set = -1;
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}
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#ifndef STD_INSPIRED
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/*
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** A non-static declaration of tzsetwall in a system header file
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@ -1149,65 +1176,71 @@ static
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void
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tzsetwall(void)
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{
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if (lcl_is_set < 0)
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return;
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lcl_is_set = -1;
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if (lock() != 0)
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return;
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tzsetwall_unlocked();
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unlock();
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}
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static void
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tzset_unlocked(void)
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{
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int shortname;
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register char const *name = getenv("TZ");
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if (!name) {
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tzsetwall_unlocked();
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return;
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}
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shortname = strlen(name) < sizeof lcl_TZname;
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if (0 < lcl_is_set && strcmp(lcl_TZname, name) == 0)
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return;
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if (shortname)
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strcpy(lcl_TZname, name);
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#ifdef ALL_STATE
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if (lclptr == NULL) {
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lclptr = malloc(sizeof *lclptr);
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if (lclptr == NULL) {
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settzname(); /* all we can do */
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return;
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}
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}
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if (! lclptr)
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lclptr = malloc(sizeof *lclptr);
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#endif /* defined ALL_STATE */
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if (tzload(NULL, lclptr, TRUE) != 0)
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gmtload(lclptr);
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settzname();
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if (lclptr) {
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if (*name == '\0') {
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/*
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** User wants it fast rather than right.
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*/
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lclptr->leapcnt = 0; /* so, we're off a little */
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lclptr->timecnt = 0;
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lclptr->typecnt = 0;
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lclptr->ttis[0].tt_isdst = 0;
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lclptr->ttis[0].tt_gmtoff = 0;
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lclptr->ttis[0].tt_abbrind = 0;
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strcpy(lclptr->chars, gmt);
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} else if (tzload(name, lclptr, TRUE) != 0)
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if (name[0] == ':' || tzparse(name, lclptr, FALSE) != 0)
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gmtload(lclptr);
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}
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settzname();
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lcl_is_set = shortname;
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}
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void
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tzset(void)
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{
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register const char * name;
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name = getenv("TZ");
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if (name == NULL) {
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tzsetwall();
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return;
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}
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if (lcl_is_set > 0 && strcmp(lcl_TZname, name) == 0)
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return;
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lcl_is_set = strlen(name) < sizeof lcl_TZname;
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if (lcl_is_set)
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(void) strcpy(lcl_TZname, name);
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if (lock() != 0)
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return;
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tzset_unlocked();
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unlock();
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}
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static void
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gmtcheck(void)
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{
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if (gmt_is_set)
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return;
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#ifdef ALL_STATE
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if (lclptr == NULL) {
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lclptr = malloc(sizeof *lclptr);
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if (lclptr == NULL) {
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settzname(); /* all we can do */
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return;
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}
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}
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#endif /* defined ALL_STATE */
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if (*name == '\0') {
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/*
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** User wants it fast rather than right.
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*/
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lclptr->leapcnt = 0; /* so, we're off a little */
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lclptr->timecnt = 0;
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lclptr->typecnt = 0;
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lclptr->ttis[0].tt_isdst = 0;
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lclptr->ttis[0].tt_gmtoff = 0;
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lclptr->ttis[0].tt_abbrind = 0;
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(void) strcpy(lclptr->chars, gmt);
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} else if (tzload(name, lclptr, TRUE) != 0)
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if (name[0] == ':' || tzparse(name, lclptr, FALSE) != 0)
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(void) gmtload(lclptr);
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settzname();
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gmtptr = malloc(sizeof *gmtptr);
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#endif
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if (gmtptr)
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gmtload(gmtptr);
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gmt_is_set = TRUE;
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}
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/*
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@ -1289,18 +1322,31 @@ localsub(const time_t *const timep, const int_fast32_t offset,
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*/
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result = timesub(&t, ttisp->tt_gmtoff, sp, tmp);
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tmp->tm_isdst = ttisp->tt_isdst;
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tzname[tmp->tm_isdst] = &sp->chars[ttisp->tt_abbrind];
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#ifdef TM_ZONE
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tmp->TM_ZONE = &sp->chars[ttisp->tt_abbrind];
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#endif /* defined TM_ZONE */
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return result;
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}
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static struct tm *
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localtime_tzset(time_t const *timep, struct tm *tmp, int skip_tzset)
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{
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int err = lock();
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if (err) {
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errno = err;
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return NULL;
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}
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if (!skip_tzset)
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tzset_unlocked();
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tmp = localsub(timep, 0, tmp);
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unlock();
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return tmp;
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}
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struct tm *
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localtime(const time_t *const timep)
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{
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tzset();
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return localsub(timep, 0L, &tm);
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return localtime_tzset(timep, &tm, 0);
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}
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/*
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@ -1310,7 +1356,7 @@ localtime(const time_t *const timep)
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struct tm *
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localtime_r(const time_t *const timep, struct tm *tmp)
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{
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return localsub(timep, 0L, tmp);
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return localtime_tzset(timep, tmp, lcl_is_set);
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}
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/*
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@ -1323,16 +1369,6 @@ gmtsub(const time_t *const timep, const int_fast32_t offset,
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{
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register struct tm * result;
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if (!gmt_is_set) {
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#ifdef ALL_STATE
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gmtptr = malloc(sizeof *gmtptr);
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gmt_is_set = gmtptr != NULL;
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#else
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gmt_is_set = TRUE;
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#endif /* defined ALL_STATE */
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if (gmt_is_set)
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gmtload(gmtptr);
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}
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result = timesub(timep, offset, gmtptr, tmp);
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#ifdef TM_ZONE
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/*
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@ -1348,7 +1384,7 @@ gmtsub(const time_t *const timep, const int_fast32_t offset,
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struct tm *
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gmtime(const time_t *const timep)
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{
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return gmtsub(timep, 0L, &tm);
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return gmtime_r(timep, &tm);
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}
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/*
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@ -1358,7 +1394,15 @@ gmtime(const time_t *const timep)
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struct tm *
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gmtime_r(const time_t *const timep, struct tm *tmp)
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{
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return gmtsub(timep, 0L, tmp);
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int err = lock();
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if (err) {
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errno = err;
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return NULL;
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}
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gmtcheck();
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tmp = gmtsub(timep, 0, tmp);
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unlock();
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return tmp;
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}
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#ifdef STD_INSPIRED
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@ -1366,7 +1410,16 @@ gmtime_r(const time_t *const timep, struct tm *tmp)
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struct tm *
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offtime(const time_t *const timep, const long offset)
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{
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return gmtsub(timep, offset, &tm);
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struct tm *tmp;
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int err = lock();
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if (err) {
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errno = err;
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return NULL;
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}
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gmtcheck();
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tmp = gmtsub(timep, offset, &tm);
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unlock();
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return tmp;
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}
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#endif /* defined STD_INSPIRED */
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@ -1901,8 +1954,16 @@ time1(struct tm *const tmp,
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time_t
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mktime(struct tm *const tmp)
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{
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tzset();
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return time1(tmp, localsub, 0L);
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time_t t;
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int err = lock();
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if (err) {
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errno = err;
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return -1;
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}
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tzset_unlocked();
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t = time1(tmp, localsub, 0);
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unlock();
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return t;
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}
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#ifdef STD_INSPIRED
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@ -1918,17 +1979,25 @@ timelocal(struct tm *const tmp)
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time_t
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timegm(struct tm *const tmp)
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{
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if (tmp != NULL)
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tmp->tm_isdst = 0;
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return time1(tmp, gmtsub, 0L);
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return timeoff(tmp, 0);
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}
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time_t
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timeoff(struct tm *const tmp, const long offset)
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{
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if (tmp != NULL)
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tmp->tm_isdst = 0;
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return time1(tmp, gmtsub, offset);
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time_t t;
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int err;
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if (tmp)
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tmp->tm_isdst = 0;
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err = lock();
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if (err) {
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errno = err;
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return -1;
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}
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gmtcheck();
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t = time1(tmp, gmtsub, offset);
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unlock();
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return t;
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}
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#endif /* defined STD_INSPIRED */
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@ -1986,8 +2055,17 @@ leapcorr(time_t *timep)
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time_t
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time2posix(time_t t)
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{
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tzset();
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return t - leapcorr(&t);
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time_t p;
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int err = lock();
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if (err) {
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errno = err;
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return -1;
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}
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if (!lcl_is_set)
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tzset_unlocked();
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p = t - leapcorr(&t);
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unlock();
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return p;
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}
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time_t
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@ -1995,8 +2073,13 @@ posix2time(time_t t)
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{
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time_t x;
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time_t y;
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tzset();
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int err = lock();
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if (err) {
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errno = err;
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return -1;
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}
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if (!lcl_is_set)
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tzset_unlocked();
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/*
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** For a positive leap second hit, the result
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** is not unique. For a negative leap second
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@ -2010,16 +2093,15 @@ posix2time(time_t t)
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x++;
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y = x - leapcorr(&x);
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} while (y < t);
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if (t != y)
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return x - 1;
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x -= y != t;
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} else if (y > t) {
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do {
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--x;
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y = x - leapcorr(&x);
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} while (y > t);
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if (t != y)
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return x + 1;
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x += y != t;
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}
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unlock();
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return x;
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}
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