I'm starting to get more into kernel hacking and building my own base system(s). Playing/reading/hacking on various UNIX-like kernels (among others) for fun lately.

Realistically, how hard would it be to port the functionality in the OpenBSD kernel that allows the above three things to function to other kernels?

Let's keep it simple and say for the sake of argument we limiting this to the two other most popular BSD kernels: NetBSD and FreeBSD. Since I see a lot of people here mentioning that they run one or the other (or both). Since like me I'm sure most people here either work with or like to play with other UNIX-like kernels for various reasons.

The reason(s) I ask:

1) Pledge/Unveil is really nice and since so much work has been done already in the OpenBSD ports tree it would be easy to port those changes to existing ports on the other OSs or apply the patches within the OpenBSD port to their existing ports.

2) If those OSs supported these features OpenBSD would benefit in return. As it would make porting software over to OpenBSD easier and most upstream projects might be willing to merge pledge/unveil patches into their projects.

3) In the case of Xenocara. It would be very nice to have the option to run the patch set on other UNIX-like OSs as opposed to default Xorg those OSs generally offer right now. Again, OpenBSD could benefit in return because more people would be working to help maintain the patch set.

These three things are probably my main reason for preferring running OpenBSD as a desktop opposed to the other *BSDs in common use right now. Well outside of the man pages and the simplicity of configuring the rest of the base system. Xenocara makes my life a lot easier since I don't have to fiddle so much with X on OpenBSD compared to the other BSDs (and Linux) to get things how I like them. It's certainly much nicer in the fact that I don't have to set it up at all post-install. It's there, it works and I can be sure I'll never break it unless I do something really stupid.

There are some kernel features I'm also interested in learning how hard it'd be to port to the other BSD kernels. But I guess I'll save those for another time.

I understand not everyone here is kernel hacking on things outside of OpenBSD. But I thought it might be interesting to ask anyway. I'm also curious about getting this stuff going on Linux of course. But I didn't want to turn this into a Linux/OpenBSD kernel debate type of thing. But again: I think OpenBSD would really benefit in return if that ever happened because a lot of stuff in the ports tree would probably no longer need OpenBSD unique patches anymore if their upstreams provided pledge/unveil out of the box.