iowatchd 0.4.0

Monitors disk IO usage and logs which processes are consuming it
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//! systemd readiness notification (`sd_notify` protocol).

/// Sends a state message (e.g. `READY=1`) to systemd through `$NOTIFY_SOCKET`.
/// It is a no-op when not started by systemd with `Type=notify`, and any
/// failure is ignored on purpose: notification is best-effort.
pub fn sd_notify(message: &str) {
    use std::os::linux::net::SocketAddrExt;
    use std::os::unix::net::{SocketAddr, UnixDatagram};

    let Some(path) = std::env::var_os("NOTIFY_SOCKET") else {
        return;
    };
    let Ok(sock) = UnixDatagram::unbound() else {
        return;
    };
    let bytes = std::os::unix::ffi::OsStrExt::as_bytes(path.as_os_str());
    let addr = match bytes.strip_prefix(b"@") {
        // A leading '@' denotes a Linux abstract socket.
        Some(name) => SocketAddr::from_abstract_name(name),
        None => SocketAddr::from_pathname(&path),
    };
    if let Ok(addr) = addr {
        let _ = sock.send_to_addr(message.as_bytes(), &addr);
    }
}