CS452 Lab03 - sample 3 (Rust)

sample2.rs

use nix::unistd::{close, dup2, fork, pipe, ForkResult};

use std::io::{self, Read, Write};
use std::process::{exit, id};
use std::str;
use std::error::Error;

const MAX: usize = 1024;

fn main() -> Result<(),Box<dyn Error>> {
  let mut buff = [0; MAX];

  let (fd_in, fd_out) = pipe()?;

  // point A
  let result = fork();

  // point B
  match result {
    Ok(ForkResult::Child) => {
      dup2(fd_out, 1)?;
      // point C
      close(fd_in)?;
      close(fd_out)?;
      // point D
      io::stdin().read(&mut buff)?;

      io::stdout().write(&buff)?;

      exit(0);
    }

    Ok(ForkResult::Parent { child: _pid }) => {
      dup2(fd_in, 0)?;
      close(fd_in)?;
      close(fd_out)?;
      io::stdin().read(&mut buff)?;
      println!("By {}: {}", id(), str::from_utf8(&buff).unwrap());
    }

    Err(error) => {
      println!("fork() error: {}", error);
      exit(-1);
    }
  }
  Ok(())
}