ConDbgX - A DbgEng-based debugger using Terminal.Gui

A demonstration of using the DbgX nuget package, with a console UI powered by Terminal.Gui

Using VS2022, you should be able to build and run ConDbgX.csproj directly. The app interprets the command line argument as a usermode app to debug, so running ConDbgX.exe cmd.exe will start a debugging session for cmd.exe.

How does it work?

The main functinoality is in CommandView.cs and CommandViewModel.cs. The CommandViewModel is the only class that talks to DbgX through the DebugEngine class. It talks to the view through data binding (using ReactiveUI) and some other events/methods. I don't really know what I'm doing with ReactiveUI, so I'm sure there are better ways to connect things together. It is important to have a functioning SynchronizationContext though, and ReactiveUI has one that works well here it seems.

Why is there a copy of TextView from Terminal.Gui?

I copied TextView and the supporting classes from the Terminal.Gui repo. The main reason was so that I could add some methods to have a better way of appending text without having to reset/reparse the entire text output every time new output is appended. I also thought it might be needed to have colored text/clickable links, but I didn't get around to adding that. There are a few other changes made to the TextView, like starting to rip out support for text wrapping (to make it easier to support clickable links).

What's working?

• Basic commands work fine, including step/go.
• Tab completion also works on the command line.
• Scrolling in the output window also works well.

What's not working?

Pretty much everything. Notably:

• No DML support, so no links or colors. Some commands that produce DML even if ".prefer_dml" is disabled, and ConDbgX makes no attempt to filter this out. It would be possible to support colored text via the TextView (or some subclass) which can set different colors per Rune.
• No support for breaking into the debugger. This would require setting up a keybinding that sends the SetInterruptRequest.
• No support for any standard debugging extension or symsrv. The DbgX package comes with only dbgeng.dll, dbgcore.dll, dbghelp.dll, dbgmodel.dll, and srcsrv.dll.
  • To add support for symbol servers like msdl.microsoft.com through symsrv.dll, adding a reference to Microsoft.Debugging.Platform.SymSrv would be needed.
  • To take advantage of the standard debugging extensions, you would probably need to change the version of dbgeng that gets loaded to be from a Windows SDK install. I think that should be possible, but I haven't tried it.
• No support for anything besides live usermode debugging. Adding support for dump debugging or kernel debugging would not be hard but would require adding command line processing.

Want to contribute?

I'm happy to take any and all contributions. I don't have specific plans for improvements on this, but I'm happy to answer any questions and help guide anyone that wants to contribute. Feel free to reach out to me on Twitter