fn fork_helper()

in reverie-ptrace/src/trace/memory.rs [214:251]
26 lines of code
1 McCabe index (conditional complexity)

    fn fork_helper<P, C, T>(mut value: T, parent: P, child: C) -> bool
    where
        P: FnOnce(Pid, T) -> bool,
        C: FnOnce(&mut T),
    {
        match unsafe { fork() }.unwrap() {
            ForkResult::Parent { child, .. } => {
                assert_eq!(
                    waitpid(child, None).unwrap(),
                    WaitStatus::Stopped(child, Signal::SIGTRAP)
                );

                let result = parent(child.into(), value);

                // Allow child to exit.
                ptrace::cont(child, None).unwrap();
                assert_eq!(waitpid(child, None).unwrap(), WaitStatus::Exited(child, 0));

                result
            }
            ForkResult::Child => {
                ptrace::traceme().unwrap();

                // Give us a chance to modify if needed.
                child(&mut value);

                // Allow parent to control when we exit. While stopped here, the
                // parent can mess with the child's memory.
                raise(Signal::SIGTRAP).unwrap();

                // Can't use the normal exit function here because we don't want
                // to call atexit handlers since `execve` was never called.
                unsafe {
                    ::libc::_exit(0);
                }
            }
        }
    }