bump perl5db.pl's $VERSION

[perl5.git] / time64.c

diff --git a/time64.c b/time64.c
index 6c75c48..52d99cd 100644 (file)
--- a/time64.c
+++ b/time64.c
@@ -115,6 +115,40 @@ static const short safe_years[SOLAR_CYCLE_LENGTH] = {
 #    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));
@@ -289,28 +323,6 @@ static void S_copy_little_tm_to_big_TM(const struct tm *src, struct TM *dest) {
 #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;
@@ -319,6 +331,7 @@ struct TM *Perl_gmtime64_r (const Time64_T *in_time, struct TM *p)
     Time64_T m;
     Time64_T time = *in_time;
     Year year = 70;
+    dTHX;
 
     assert(p != NULL);
 
@@ -326,9 +339,30 @@ struct TM *Perl_gmtime64_r (const Time64_T *in_time, struct TM *p)
     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;
+
+        GMTIME_LOCK;
+
+        /* reentr.h will automatically replace this with a call to gmtime_r()
+         * when appropriate */
+        result = gmtime(&safe_time);
+
+        assert(result != NULL);
 
-        S_copy_little_tm_to_big_TM(&safe_date, p);
+#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;
@@ -340,7 +374,7 @@ struct TM *Perl_gmtime64_r (const Time64_T *in_time, struct TM *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);
@@ -445,7 +479,7 @@ struct TM *Perl_localtime64_r (const Time64_T *time, struct TM *local_tm)
     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;
@@ -478,11 +512,14 @@ struct TM *Perl_localtime64_r (const Time64_T *time, struct TM *local_tm)
         safe_time = (time_t)S_timegm64(&gm_tm);
     }
 
+    LOCALTIME_LOCK;
+
     /* reentr.h will automatically replace this with a call to localtime_r()
      * when appropriate */
     result = localtime(&safe_time);
 
-    if( result == NULL ) {
+    if(UNLIKELY(result == NULL)) {
+        LOCALTIME_UNLOCK;
         TIME64_TRACE1("localtime(%d) returned NULL\n", (int)safe_time);
         return NULL;
     }
@@ -496,12 +533,15 @@ struct TM *Perl_localtime64_r (const Time64_T *time, struct TM *local_tm)
     /* 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 can jump in and trash this result. */
+     * 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) {