Added safety checks

sapi/apache2handler/php_functions.c

@@ -58,13 +58,11 @@ php_apache2_info_struct php_apache2_info;
 
 static request_rec *php_apache_lookup_uri(char *filename TSRMLS_DC)
 {
-	php_struct *ctx;
+	php_struct *ctx = SG(server_context);
 	
-	if (!filename) {
+	if (!filename || !ctx || !ctx->r) {
 		return NULL;
 	}
-	
-	ctx = SG(server_context);
 
 	return ap_sub_req_lookup_uri(filename, ctx->r, ctx->r->output_filters);
 }