kernel - C# driver development?

Question

Before I jump headlong into C#...

I've always felt that C, or maybe C++, was best for developing drivers on Windows. I'm not keen on the idea of developing a driver on a .NET machine.

But .NET seems to be the way MS is heading for applications development, and so I'm now wondering:

• Are people are using C# to develop drivers?
• Do you have to do a lot of API hooks, or does C# have the facilities to interface with the kernel without a lot of hackery?
• Can anyone speak to the reliability and safety of running a C# program closer to Ring 0 than would normally be the case?

I want my devices to be usable in C#, and if driver dev in C# is mature that's obviously the way to go, but I don't want to spend a lot of effort there if it's not recommended.

• What are some good resources to get started, say, developing a simple virtual serial port driver?

-Adam

Answer 1

You can not make kernel-mode device drivers in C# as the runtime can't be safely loaded into ring0 and operate as expected.

Additionally, C# doesn't create binaries suitable for loading as device drivers, particularly regarding entry points that drivers need to expose. The dependency on the runtime to jump in and analyze and JIT the binary during loading prohibits the direct access the driver subsystem needs to load the binary.

There is work underway, however, to lift some device drivers into user mode, you can see an interview here with Peter Wieland of the UDMF (User Mode Driver Framework) team.

User-mode drivers would be much more suited for managed work, but you'll have to google a bit to find out if C# and .NET will be directly supported. All I know is that kernel level drivers are not doable in only C#.

You can, however, probably make a C/C++ driver, and a C# service (or similar) and have the driver talk to the managed code, if you absolutely have to write a lot of code in C#.