Chameleon: Multi-Persona Binary Compatibility for Mobile Devices

Mobile devices are vertically integrated systems that are powerful, useful platforms, but unfortunately limit user choice and lock users and developers into a particular mobile ecosystem, such as iOS or Android. We present Chameleon, a multi-persona binary compatibility architecture that allows mobile device users to run applications built for different mobile ecosystems together on the same smartphone or tablet. Chameleon enhances the domestic operating system of a device with personas to mimic the application binary interface of a foreign operating system to run unmodified foreign binary applications. To accomplish this without reimplementing the entire foreign operating system from scratch, Chameleon provides four key mechanisms. First, a multi-persona binary interface is used that can load and execute both domestic and foreign applications that use different sets of system calls. Second, compile-time code adaptation makes it simple to reuse existing unmodified foreign kernel code in the domestic kernel. Third, API interposition and passport system calls make it possible to reuse foreign user code together with domestic kernel facilities to support foreign kernel functionality in user space. Fourth, schizophrenic processes allow foreign applications to use domestic libraries to access proprietary software and hardware interfaces on the device. We have built a Chameleon prototype and demonstrate that it imposes only modest performance overhead and can run iOS applications from the Apple App Store together with Android applications from Google Play on a Nexus 7 tablet running the latest version of Android.