Automated and Portable Native Code Isolation

The coexistence of programs written in a safe language with user-supplied unsafe (native) code is convenient (it enables direct access to hardware and operating system resources and can improve application performance), but at the same time it is problematic (it leads to undesirable interference with the language runtime, decreases overall reliability, and lowers debuggability). This work aims at retaining most of the benefits of interfacing a safe language with native code while addressing its problems. It is carried out in the context of the JavaTM Native Interface (JNI). Our approach is to execute the native code in an operating system process different from that of the safe language application. A technique presented in this paper accomplishes this transparently, automatically, and without sacrificing any of the JNI functionality. No changes to the Java virtual machine (JVMTM) or its runtime are necessary. The resulting prototype does not depend on a particular implementation of the JVM, and is highly portable across hardware architectures and operating systems. This approach can readily be used to improve reliability of applications consisting of a mix of safe and native code; to enable the execution of user-supplied native code in multitasking systems based on safe languages and in embedded virtual machines; and to facilitate mixed-mode debugging, without the need to re-implement any of the components of the language runtime. The design and implementation of a prototype system, performance implications, and the potential of this architecture are discussed in the paper.