Supporting flexible safety and sharing in multi-threaded environments

Abstract

There is increasing interest in extensible systems (such as extensible operating systems, mobile code runtime systems, Internet browsers and servers) that allow external programs to be downloaded and executed directly within the system. While appealing from system design and extensibility points of view, extensible systems are vulnerable to aberrant behaviors of external programs. External programs can interfere with executions of other programs by reading and writing into their memory locations. In this paper, we present an approach for providing safe execution of external programs through a safe threads mechanism. The approach also provides a novel technique for safe sharing among external programs. The paper also describes the design and implementation of the safe threads.

This work is supported by the Defense Advanced Research Project Agency (DARPA) and Rome Laboratory, Air Force Materiel Command, USAF, under agreement number F30602-97-1-0221. The U.S. Government is authorized to reproduce and distribute reprints for Governmental purposes notwithstanding any copyright annotation thereon. The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of the Defense Advanced Research Project Agency (DARPA), Rome Laboratory, or the U.S. Government.