[Question] I'm trying to manipulate keystrokes in Go using evdev, uinput, and syscall and I've hit a snag. Any assistance would be appreciated.

Hello everyone!

To start: I'm relatively new to Go and compiled languages in general. The overwhelming majority of my dev experience is with PHP and Python. That said, I spent several hours the other night trying to make my laptop keyboard act like my desktop keyboard. It's called a Poker 3 and it's a minimal 61 key layout that maps all the extra keys using an extra function key, and it has a switch to turn the caps lock key into the extra function key as well. Turns out there is absolutely no reasonable way to emulate this in Linux with existing software, so here we are.

Anyway, I've been able to get a solid proof-of-concept working in Python with only one major snag and this is largely to do with the rather well put together and well documented python-evdev library. While I was half brain-dead from lack of sleep dealing with said snag I thought I'd take on my first reasonably practical Go project.

Here's the Python proof-of-concept: https://gist.github.com/kendalltristan/aa873137751e3f11a9102e1174ec0d61

Here's the Go implementation thus far: https://gist.github.com/kendalltristan/9fcd9c4b700b22cafc7789cfca4e8a2c

To the specifics, the issue I'm having is with syscall calling ioctl. Essentially in order to accomplish what I need to accomplish, input from non-specified keys needs to be prevented while holding down the caps lock key. The function in question begins on line 23 and is called from lines 100 and 106. Go's syscall library doesn't have a function for ioctl so I had to steal one from somewhere. Anyway, that part seems to work; the larger issue is that once I "grab" the input device, I can't seem to "ungrab" it (look at the Python implementation to get what I mean). Basically pressing the caps lock key now effectively shuts off the keyboard while the program is running.

Now some input absolutely should be prevented so I'm reasonably certain I'm pointed in the right direction. Now I'm in the position of not knowing either enough Go or enough of how input interacts with the kernel to progress any farther. If anyone can offer assistance, I'd greatly appreciate it and I'll be happy to buy gold for anyone who can provide or point me to a solution. Thanks in advance for your time and assistance. Cheers.

It's called a Poker 3 and it's a minimal 61 key layout that maps all the extra keys using an extra function key, and it has a switch to turn the caps lock key into the extra function key as well. Turns out there is absolutely no reasonable way to emulate this in Linux with existing software, so here we are.

Really? All of that sounds very similar to what the neo-layout does and that works with straight xkb/xmodmap. It has 6 layers, accessed through combinations of 3 modifiers and relies both on reusing capslock as a modifier and remapping two keys that aren't normally modifiers to be modifiers.

I can't really help you with your actual problem, but maybe looking at what neo does can help you achieve the same thing with stock linux software?