look_path.rs

use std::path::Path;

static PATHS: [&'static str, .. 4] = ["/bin", "/sbin", "/usr/bin", "/usr/sbin"];

// Tries to find an executable
// TODO: Look for the executable bit for the select user/group
fn look_path(program: ~str, root: ~Path) -> Option<Path> {
  let cmd = Path::new(program.clone());
  if cmd.is_absolute() || program.contains("/") { // TODO: Use path::SEP
    Some(cmd)
  } else {
    let paths = PATHS.map(|p| Path::new(p.as_bytes()).join(cmd.clone()));
    match paths.iter().find(|p| root.join(*p).is_file()) {
      Some(m) => Some(m.clone()),
      None => None
    }
  }
}

fn main() {
  match look_path(~"ls", ~Path::new("/")) {
    Some(cmd) => println!("command found: {}", cmd.as_str().unwrap()),
    None => println!("No command found")
  }
}