Some of FreeBSD Ported to WebAssembly

For use in https://cowasm.org.

• This includes many of the coreutils in the utils directory. We aren't porting everything, e.g., chroot doesn't make a lot of sense in the context of WebAssembly/WASI.

Known broken things

• [ ] tail -f doesn't work because epoll isn't implemented in cowasm yet. See posix/epoll.ts elsewhere.

• [ ] split doesn't work due to freopen and other issues I haven't looked into yet.

• [ ] expand foo doesn't work when input is a file instead of stdin. This is because the implementation uses freopen to make the file into stdin, which is a pretty neat trick. The fix isn't to rewrite expand, but instead to fix freopen. This is extra challenging because our code for running processes then restoring state has to deal with this properly, and probably doesn't now (?). There's also a test of freopen for wasi here that might be inspiring.

  • Similarly, fold is broken for exactly the same reason
  • Also nl is broken.

TODO

• [ ] the env coreutil calls execvp. We should make it work with WASM targets as well. That might just mean changing execvp though, since there is no fork -- it's just exec, which is maybe easier.

Sources

• https://github.com/freebsd/freebsd-src
• https://github.com/coreutils/coreutils
• https://github.com/DiegoMagdaleno/BSDCoreUtils