*/
+
+/*
+ * This thing all things devours:
+ * Birds, beasts, trees, flowers;
+ * Gnaws iron, bites steel;
+ * Grinds hard stones to meal;
+ * Slays king, ruins town,
+ * And beats high mountain down."
+ *
+ * Poor Bilbo sat in the dark thinking of all the horrible names of all the
+ * giants and ogres he had ever heard told of in tales, but not one of them had
+ * done all these things. He had a feeling that the answer was quite different
+ * and that he ought to know it, but he could not think of it. He began to get
+ * frightened, and that is bad for thinking. Gollum began to get out of his
+ * boat. He flapped into the water and paddled to the bank; Bilbo could see his
+ * eyes coming towards him. His tongue seemed to stick in his mouth; he wanted
+ * to shout out: "Give me more time! Give me time!" But all that came out with
+ * a sudden squeal was:
+ *
+ * "Time! Time!"
+ *
+ * Bilbo was saved by pure luck. For that of course was the answer.
+ *
+ * [p.84 of _The Hobbit_: "Riddles in the Dark"]
+ *
+*/
+
/*
Programmers who have available to them 64-bit time values as a 'long
# define TIME64_TRACE3(format, var1, var2, var3) ((void)0)
#endif
+/* Set up the mutexes for this file. There are no races possible on
+ * non-threaded perls, nor platforms that naturally don't have them.
+ * Otherwise, we need to have mutexes. If we have reentrant versions of the
+ * functions below, they automatically will be substituted for the
+ * non-reentrant ones. That solves the problem of the buffers being trashed by
+ * another thread, but not of the environment or locale changing during their
+ * execution. To do that, we only need a read lock (which prevents writing by
+ * others). However, if we don't have re-entrant functions, we can gain some
+ * measure of thread-safety by using an exclusive lock during their execution.
+ * That will protect against any other use of the functions that use the
+ * mutexes, which all of core should be using. */
+#ifdef USE_REENTRANT_API /* This indicates a platform where we need reentrant
+ versions if have them */
+# ifdef PERL_REENTR_USING_LOCALTIME_R
+# define LOCALTIME_LOCK ENV_LOCALE_READ_LOCK
+# define LOCALTIME_UNLOCK ENV_LOCALE_READ_UNLOCK
+# else
+# define LOCALTIME_LOCK ENV_LOCALE_LOCK
+# define LOCALTIME_UNLOCK ENV_LOCALE_UNLOCK
+# endif
+# ifdef PERL_REENTR_USING_GMTIME_R
+# define GMTIME_LOCK ENV_LOCALE_READ_LOCK
+# define GMTIME_UNLOCK ENV_LOCALE_READ_UNLOCK
+# else
+# define GMTIME_LOCK ENV_LOCALE_LOCK
+# define GMTIME_UNLOCK ENV_LOCALE_UNLOCK
+# endif
+#else /* Reentrant not needed, so races not possible */
+# define LOCALTIME_LOCK NOOP
+# define LOCALTIME_UNLOCK NOOP
+# define GMTIME_LOCK NOOP
+# define GMTIME_UNLOCK NOOP
+#endif
+
static int S_is_exception_century(Year year)
{
const int is_exception = ((year % 100 == 0) && !(year % 400 == 0));
#endif
}
-
-#ifndef HAS_LOCALTIME_R
-/* Simulate localtime_r() to the best of our ability */
-static struct tm * S_localtime_r(const time_t *clock, struct tm *result) {
-#ifdef __VMS
- dTHX; /* the following is defined as Perl_my_localtime(aTHX_ ...) */
-#endif
- const struct tm * const static_result = localtime(clock);
-
- assert(result != NULL);
-
- if( static_result == NULL ) {
- memset(result, 0, sizeof(*result));
- return NULL;
- }
- else {
- memcpy(result, static_result, sizeof(*result));
- return result;
- }
-}
-#endif
-
-#ifndef HAS_GMTIME_R
-/* Simulate gmtime_r() to the best of our ability */
-static struct tm * S_gmtime_r(const time_t *clock, struct tm *result) {
-#ifdef __VMS
- dTHX; /* the following is defined as Perl_my_localtime(aTHX_ ...) */
-#endif
- const struct tm * const static_result = gmtime(clock);
-
- assert(result != NULL);
-
- if( static_result == NULL ) {
- memset(result, 0, sizeof(*result));
- return NULL;
- }
- else {
- memcpy(result, static_result, sizeof(*result));
- return result;
- }
-}
-#endif
-
struct TM *Perl_gmtime64_r (const Time64_T *in_time, struct TM *p)
{
int v_tm_sec, v_tm_min, v_tm_hour, v_tm_mon, v_tm_wday;
Time64_T m;
Time64_T time = *in_time;
Year year = 70;
+ dTHX;
assert(p != NULL);
if( SHOULD_USE_SYSTEM_GMTIME(*in_time) ) {
time_t safe_time = (time_t)*in_time;
struct tm safe_date;
- GMTIME_R(&safe_time, &safe_date);
+ struct tm * result;
- S_copy_little_tm_to_big_TM(&safe_date, p);
+ GMTIME_LOCK;
+
+ /* reentr.h will automatically replace this with a call to gmtime_r()
+ * when appropriate */
+ result = gmtime(&safe_time);
+
+ assert(result != NULL);
+
+#if defined(HAS_GMTIME_R) && defined(USE_REENTRANT_API)
+
+ PERL_UNUSED_VAR(safe_date);
+#else
+ /* Here, no gmtime_r() and is a threaded perl where the result can be
+ * overwritten by a call in another thread. Copy to a safe place,
+ * hopefully before another gmtime that isn't using the mutexes can
+ * jump in and trash this result. */
+ memcpy(&safe_date, result, sizeof(safe_date));
+ result = &safe_date;
+#endif
+ GMTIME_UNLOCK;
+
+ S_copy_little_tm_to_big_TM(result, p);
assert(S_check_tm(p));
return p;
p->tm_isdst = 0;
#ifdef HAS_TM_TM_ZONE
- p->tm_zone = (char *)"UTC";
+ p->tm_zone = "UTC";
#endif
v_tm_sec = (int)Perl_fmod(time, 60.0);
{
time_t safe_time;
struct tm safe_date;
+ const struct tm * result;
struct TM gm_tm;
- Year orig_year;
+ Year orig_year = 0; /* initialise to avoid spurious compiler warning */
int month_diff;
const bool use_system = SHOULD_USE_SYSTEM_LOCALTIME(*time);
+ dTHX;
assert(local_tm != NULL);
safe_time = (time_t)S_timegm64(&gm_tm);
}
- if( LOCALTIME_R(&safe_time, &safe_date) == NULL ) {
- TIME64_TRACE1("localtime_r(%d) returned NULL\n", (int)safe_time);
+ LOCALTIME_LOCK;
+
+ /* reentr.h will automatically replace this with a call to localtime_r()
+ * when appropriate */
+ result = localtime(&safe_time);
+
+ if(UNLIKELY(result == NULL)) {
+ LOCALTIME_UNLOCK;
+ TIME64_TRACE1("localtime(%d) returned NULL\n", (int)safe_time);
return NULL;
}
- S_copy_little_tm_to_big_TM(&safe_date, local_tm);
+#if ! defined(USE_REENTRANT_API) || defined(PERL_REENTR_USING_LOCALTIME_R)
+
+ PERL_UNUSED_VAR(safe_date);
+
+#else
+
+ /* Here, would be using localtime_r() if it could, meaning there isn't one,
+ * and is a threaded perl where the result can be overwritten by a call in
+ * another thread. Copy to a safe place, hopefully before another
+ * localtime that isn't using the mutexes can jump in and trash this
+ * result. */
+ memcpy(&safe_date, result, sizeof(safe_date));
+ result = &safe_date;
+
+#endif
+
+ LOCALTIME_UNLOCK;
+
+ S_copy_little_tm_to_big_TM(result, local_tm);
if (! use_system) {
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