type ExResult<T> = Result<T, Box<dyn std::error::Error + 'static>>;

fn manipulate_caps() -> ExResult<()> {
    use caps::{Capability, CapSet};

    // Retrieve permitted set.
    let cur = caps::read(None, CapSet::Permitted)?;
    println!("Current permitted caps: {:?}.", cur);
    
    // Retrieve effective set.
    let cur = caps::read(None, CapSet::Effective)?;
    println!("Current effective caps: {:?}.", cur);
    
    // Check if CAP_CHOWN is in permitted set.
    let perm_chown = caps::has_cap(None, CapSet::Permitted, Capability::CAP_CHOWN)?;
    if !perm_chown {
        return Err("Try running this as root!".into());
    }

    // Clear all effective caps.
    caps::clear(None, CapSet::Effective)?;
    println!("Cleared effective caps.");
    let cur = caps::read(None, CapSet::Effective)?;
    println!("Current effective caps: {:?}.", cur);

    // Since `CAP_CHOWN` is still in permitted, it can be raised again.
    caps::raise(None, CapSet::Effective, Capability::CAP_CHOWN)?;
    println!("Raised CAP_CHOWN in effective set.");
    let cur = caps::read(None, CapSet::Effective)?;
    println!("Current effective caps: {:?}.", cur);

    Ok(())
}