Allow get_request_time() hook to fail

In particular, this allows using the hook without server_context.
The apache2handler implementation now checks that server_context
is available itself, as that's the implementation that cares
about it.

Author: nikic

main/SAPI.c

@@ -1073,9 +1073,8 @@ SAPI_API double sapi_get_request_time(void)
 {
 	if(SG(global_request_time)) return SG(global_request_time);
 
-	if (sapi_module.get_request_time && SG(server_context)) {
-		SG(global_request_time) = sapi_module.get_request_time();
-	} else {
+	if (!sapi_module.get_request_time
+			|| sapi_module.get_request_time(&SG(global_request_time)) == FAILURE) {
 		struct timeval tp = {0};
 		if (!gettimeofday(&tp, NULL)) {
 			SG(global_request_time) = (double)(tp.tv_sec + tp.tv_usec / 1000000.00);

main/SAPI.h

@@ -236,7 +236,7 @@ struct _sapi_module_struct {
 
 	void (*register_server_variables)(zval *track_vars_array);
 	void (*log_message)(const char *message, int syslog_type_int);
-	double (*get_request_time)(void);
+	zend_result (*get_request_time)(double *request_time);
 	void (*terminate_process)(void);
 
 	char *php_ini_path_override;

sapi/apache2handler/sapi_apache2.c

@@ -363,10 +363,15 @@ static void php_apache_sapi_log_message_ex(const char *msg, request_rec *r)
 	}
 }
 
-static double php_apache_sapi_get_request_time(void)
+static zend_result php_apache_sapi_get_request_time(double *request_time)
 {
 	php_struct *ctx = SG(server_context);
-	return ((double) ctx->r->request_time) / 1000000.0;
+	if (!ctx) {
+		return FAILURE;
+	}
+
+	*request_time = ((double) ctx->r->request_time) / 1000000.0;
+	return SUCCESS;
 }
 
 extern zend_module_entry php_apache_module;