Rhook

Hooks libc functions with an easy API

Example

Say you want to limit the badnwhidth of a program

Usually downloading calls libc::recv function

So our goal is to throttle it with a simple sleep

To do that with this crate: (taking speedtest program as an example)

1- Check its manpage https://man7.org/linux/man-pages/man2/recv.2.html to see what the function's input/output

2- use this crate

run_with(vec!("speedtest"), vec!(Hook::Recv(stringify!(|sockfd, buf, len, flags|{
  std::thread::sleep_ms(100);
  original_recv(sockfd, buf, len, flags)
}))))

Thats it! Note that you have acess inside the closure to the original function denoted by the prefix original_ + the function name

Couple of points:

• If you take ownership of an input value inside of the closure, be sure to use ManuallyDrop so you don't free it

Check out the tests for more examples