User-mode Simulation of Windows Kernel APIs

This project is designed to allow a Windows kernel driver developer to compile their code as a user-mode DLL for testing purposes, so that it can be used for code coverage, fuzzers, etc.

Using

To use this repository from another project:

1. Include this repository as a git submodule from your project.
2. Build your driver files as a DLL. That is, create a new project or directory, and have it include the same source files as your driver does, but set the configuration type to be a Dynamic Library. See the "sample" project as an example, which builds the KMDF sample driver as a DLL (the sample project can be built either using Visual Studio or using cmake).
3. Define the preprocessor symbol USERSIM_DLLMAIN when building one file (typically the one containing your DriverEntry) that includes wdf.h. The sample project does this not in the driver.c source file itself but rather in the sample.vcxproj that builds it, but all that is important is defining it before including wdf.h.
4. Add a reference from your DLL project to the usersim project.

Leak Detection

To detect memory leaks on exit, define the environment variable USERSIM_MEMORY_LEAK_DETECTION=true

Fault Injection

To use fault injection, define the environment variable USERSIM_FAULT_INJECTION_SIMULATION=4 where the value (4 in this example) is the number of stack frames to use to determine whether a call stack is unique. Fault injection will cause one call into the UserSim library to fail, for every unique call stack.

Contributing

This project welcomes contributions and suggestions. Most contributions require you to agree to a Contributor License Agreement (CLA) declaring that you have the right to, and actually do, grant us the rights to use your contribution. For details, visit https://cla.opensource.microsoft.com.

When you submit a pull request, a CLA bot will automatically determine whether you need to provide a CLA and decorate the PR appropriately (e.g., status check, comment). Simply follow the instructions provided by the bot. You will only need to do this once across all repos using our CLA.

This project has adopted the Microsoft Open Source Code of Conduct. For more information see the Code of Conduct FAQ or contact opencode@microsoft.com with any additional questions or comments.

Trademarks

This project may contain trademarks or logos for projects, products, or services. Authorized use of Microsoft trademarks or logos is subject to and must follow Microsoft's Trademark & Brand Guidelines. Use of Microsoft trademarks or logos in modified versions of this project must not cause confusion or imply Microsoft sponsorship. Any use of third-party trademarks or logos are subject to those third-party's policies.