goLogKeys

Go Log Keys

Simple key logger written in C and Go.

Its intended use it to register some keys (from a JSON file or something), and register key events (press/release) through a WebSocket to my stream overlay, so it can display which keyboard keys (mapped to a controller or something) are currently pressed.

Logging on Windows

Windows allows setting a callback for global keyboard events. However, it must have been loaded from a DLL, instead of from the current process...

./winDll/logger.c implements the callback, keyCallback, and a function to retrieve all keypresses, pop.

Note that (from this StackOverflow answer) that sleep etc blocks the callback... So, that DLL also has a function, wait, that creates a dummy window, which may be used to keep the logger alive.

With mxe installed, you may compile the DLL and the test with:

export CC=x86_64-w64-mingw32.shared-gcc
${CC} -shared -Wl,-soname,logger.dll -Wl,-export-all-symbols -o logger64.dll winDll/logger.c
${CC} -o test64.exe winDll/test.c

Note that I use the 64-bit MinGW compiler... I could only get this to work by using a 64-bit DLL along with a 64-bit test application (in my 64-bit system). However, I believe that injecting a 32-bit DLL into a 32-bit application in a 64-bit system should be possible...

Building the Go part should be quite straight forward... Try to build it and go get anything that fails:

go get -d github.com/pkg/errors
go get -d golang.org/x/sys/windows
go get -d github.com/SirGFM/GoWebSocketProxy/websocket
GOOS=windows GOARCH=amd64 go build

Logging on Linux

Be sure to install python3-xlib! Other than that, this should work out of the box.

go get -d github.com/pkg/errors
go get -d github.com/SirGFM/GoWebSocketProxy/websocket
go build

Resources

Non exhaustive list of resources used to write all this:

• MSDN: LowLevelKeyboardProc callback function
• MSDN: KBDLLHOOKSTRUCT structure
• MSDN: SetWindowsHookEx function
• MSDN: Installing and Releasing Hook Procedures
• SO: SetWindowsHookEx with WH_KEYBOARD doesn't work for me, what do I wrong?
• Go: Calling a Windows DLL
• golang.org/x/sys/windows