Umbra – A Tutorial from client share detect.c

Umbra is an efficient and scalable memory shadowing tool built on top of DynamoRIO, which is a state-ofthe-art runtime code manipulation system. Using the APIs provided by DynamoRIO, Umbra inserts code into the applications runtime instruction stream to perform memory address translation from application memory to shadow memory. Umbra also provides a simple interface that enables developers to create custom shadow memory clients without requiring them to understand Umbra’s memory translation details. This document illustrates how Umbra can be used to develop shadow memory tools via a sample client. The client detects shared data accesses to memory, and reports interesting memory access statistics for a target application.