Repository: alacritty/alacritty
File: alacritty_terminal/src/tty/unix.rs (Rust)

Code before:
/// Create a new TTY from a PTY's file descriptors.
pub fn from_fd(config: &Options, window_id: u64, master: OwnedFd, slave: OwnedFd) -> Result<Pty> {
    let master_fd = master.as_raw_fd();
    let slave_fd = slave.as_raw_fd();

    #[cfg(any(target_os = "linux", target_os = "macos"))]
    if let Ok(mut termios) = termios::tcgetattr(&master) {
        // Set character encoding to UTF-8.
        termios.input_modes.set(InputModes::IUTF8, true);
        let _ = termios::tcsetattr(&master, OptionalActions::Now, &termios);
    }

    let user = ShellUser::from_env()?;

    let mut builder = if let Some(shell) = config.shell.as_ref() {
        let mut cmd = Command::new(&shell.program);
        cmd.args(shell.args.as_slice());
        cmd
    } else {
        default_shell_command(&user.shell, &user.user)
    };

    // Setup child stdin/stdout/stderr as slave fd of PTY.
    builder.stdin(rustix_openpty::rustix::io::dup(&slave)?);
    builder.stderr(rustix_openpty::rustix::io::dup(&slave)?);
    builder.stdout(slave);

    // Setup shell environment.
    let window_id = window_id.to_string();
    builder.env("ALACRITTY_WINDOW_ID", &window_id);
    builder.env("USER", user.user);
    builder.env("HOME", user.home);
    // Set Window ID for clients relying on X11 hacks.
    builder.env("WINDOWID", window_id);
    for (key, value) in &config.env {
        builder.env(key, value);
    }

    unsafe {
        builder.pre_exec(move || {
            // Create a new process group.
            let err = libc::setsid();
            if err == -1 {
                return Err(Error::new(ErrorKind::Other, "Failed to set session id"));
            }

            set_controlling_terminal(slave_fd);

            // No longer need slave/master fds.
            libc::close(slave_fd);
            libc::close(master_fd);

Review comment (suggestion):
You can just `try_clone` the `fd`, you don't need the `dup` from the `rustix` iirc.

Code after:
/// Create a new TTY from a PTY's file descriptors.
pub fn from_fd(config: &Options, window_id: u64, master: OwnedFd, slave: OwnedFd) -> Result<Pty> {
    let master_fd = master.as_raw_fd();
    let slave_fd = slave.as_raw_fd();

    #[cfg(any(target_os = "linux", target_os = "macos"))]
    if let Ok(mut termios) = termios::tcgetattr(&master) {
        // Set character encoding to UTF-8.
        termios.input_modes.set(InputModes::IUTF8, true);
        let _ = termios::tcsetattr(&master, OptionalActions::Now, &termios);
    }

    let user = ShellUser::from_env()?;

    let mut builder = if let Some(shell) = config.shell.as_ref() {
        let mut cmd = Command::new(&shell.program);
        cmd.args(shell.args.as_slice());
        cmd
    } else {
        default_shell_command(&user.shell, &user.user)
    };

    // Setup child stdin/stdout/stderr as slave fd of PTY.
    builder.stdin(slave.try_clone()?);
    builder.stderr(slave.try_clone()?);
    builder.stdout(slave);

    // Setup shell environment.
    let window_id = window_id.to_string();
    builder.env("ALACRITTY_WINDOW_ID", &window_id);
    builder.env("USER", user.user);
    builder.env("HOME", user.home);
    // Set Window ID for clients relying on X11 hacks.
    builder.env("WINDOWID", window_id);
    for (key, value) in &config.env {
        builder.env(key, value);
    }

    unsafe {
        builder.pre_exec(move || {
            // Create a new process group.
            let err = libc::setsid();
            if err == -1 {
                return Err(Error::new(ErrorKind::Other, "Failed to set session id"));
            }

            set_controlling_terminal(slave_fd);

            // No longer need slave/master fds.
            libc::close(slave_fd);
            libc::close(master_fd);