6800586: -XX:+PrintGCDateStamps is using mt-unsafe localtime function

Summary: replaced localtime() with localtime_r() on Solaris and Linux.
Reviewed-by: apetrusenko, dholmes, jmasa

src/os/linux/vm/os_linux.cpp

@@ -1432,6 +1432,10 @@ char * os::local_time_string(char *buf, size_t buflen) {
   return buf;
 }
 
+struct tm* os::localtime_pd(const time_t* clock, struct tm*  res) {
+  return localtime_r(clock, res);
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // runtime exit support
 

src/os/solaris/vm/os_solaris.cpp

@@ -323,6 +323,10 @@ size_t os::current_stack_size() {
   return (size_t)(base - bottom);
 }
 
+struct tm* os::localtime_pd(const time_t* clock, struct tm*  res) {
+  return localtime_r(clock, res);
+}
+
 // interruptible infrastructure
 
 // setup_interruptible saves the thread state before going into an

src/os/windows/vm/os_windows.cpp

@@ -327,6 +327,14 @@ size_t os::current_stack_size() {
   return sz;
 }
 
+struct tm* os::localtime_pd(const time_t* clock, struct tm* res) {
+  const struct tm* time_struct_ptr = localtime(clock);
+  if (time_struct_ptr != NULL) {
+    *res = *time_struct_ptr;
+    return res;
+  }
+  return NULL;
+}
 
 LONG WINAPI topLevelExceptionFilter(struct _EXCEPTION_POINTERS* exceptionInfo);
 

src/share/vm/runtime/os.cpp

@@ -74,13 +74,11 @@ char* os::iso8601_time(char* buffer, size_t buffer_length) {
   const int milliseconds_after_second =
     milliseconds_since_19700101 % milliseconds_per_microsecond;
   // Convert the time value to a tm and timezone variable
-  const struct tm *time_struct_temp = localtime(&seconds_since_19700101);
-  if (time_struct_temp == NULL) {
-    assert(false, "Failed localtime");
+  struct tm time_struct;
+  if (localtime_pd(&seconds_since_19700101, &time_struct) == NULL) {
+    assert(false, "Failed localtime_pd");
     return NULL;
   }
-  // Save the results of localtime
-  const struct tm time_struct = *time_struct_temp;
   const time_t zone = timezone;
 
   // If daylight savings time is in effect,
@@ -93,10 +91,10 @@ char* os::iso8601_time(char* buffer, size_t buffer_length) {
     UTC_to_local = UTC_to_local - seconds_per_hour;
   }
   // Compute the time zone offset.
-  //    localtime(3C) sets timezone to the difference (in seconds)
+  //    localtime_pd() sets timezone to the difference (in seconds)
   //    between UTC and and local time.
   //    ISO 8601 says we need the difference between local time and UTC,
-  //    we change the sign of the localtime(3C) result.
+  //    we change the sign of the localtime_pd() result.
   const time_t local_to_UTC = -(UTC_to_local);
   // Then we have to figure out if if we are ahead (+) or behind (-) UTC.
   char sign_local_to_UTC = '+';

src/share/vm/runtime/os.hpp

@@ -121,6 +121,7 @@ class os: AllStatic {
   // It is MT safe, but not async-safe, as reading time zone
   // information may require a lock on some platforms.
   static char*      local_time_string(char *buf, size_t buflen);
+  static struct tm* localtime_pd     (const time_t* clock, struct tm*  res);
   // Fill in buffer with current local time as an ISO-8601 string.
   // E.g., YYYY-MM-DDThh:mm:ss.mmm+zzzz.
   // Returns buffer, or NULL if it failed.