RedBear-OS/src/header/pty/linux.rs

use core::ptr;

use crate::{
    header::{fcntl, sys_ioctl, unistd},
    io::{Cursor, Write},
    platform::types::{c_char, c_int, c_void},
};

pub(super) unsafe fn openpty(name: &mut [u8]) -> Result<(c_int, c_int), ()> {
    //TODO: wrap in auto-close struct
    let master = unsafe { fcntl::open(c"/dev/ptmx".as_ptr(), fcntl::O_RDWR | fcntl::O_NOCTTY, 0) };
    if master < 0 {
        return Err(());
    }

    let mut lock: c_int = 0;
    if unsafe {
        sys_ioctl::ioctl(
            master,
            sys_ioctl::TIOCSPTLCK,
            ptr::from_mut::<c_int>(&mut lock).cast::<c_void>(),
        )
    } != 0
    {
        unistd::close(master);
        return Err(());
    }

    let mut ptn: c_int = 0;
    if unsafe {
        sys_ioctl::ioctl(
            master,
            sys_ioctl::TIOCGPTN,
            ptr::from_mut::<c_int>(&mut ptn).cast::<c_void>(),
        )
    } != 0
    {
        unistd::close(master);
        return Err(());
    }

    let mut cursor = Cursor::new(name);
    if let Ok(()) = write!(cursor, "/dev/pts/{}\0", ptn) {}; // TODO handle error

    let slave = unsafe {
        fcntl::open(
            cursor.get_ref().as_ptr().cast::<c_char>(),
            fcntl::O_RDWR | fcntl::O_NOCTTY,
            0,
        )
    };
    if slave < 0 {
        unistd::close(master);
        return Err(());
    }

    Ok((master, slave))
}