// Copyright 2018 Yuya Nishihara <yuya@tcha.org>

//

// This software may be used and distributed according to the terms of the

// GNU General Public License version 2 or any later version.

//! Low-level utility for signal and process handling.

use libc::{self, c_int, size_t, ssize_t};

use std::io;

use std::os::unix::io::RawFd;

#[link(name = "procutil", kind = "static")]

extern "C" {

    // sendfds.c

    fn sendfds(sockfd: c_int, fds: *const c_int, fdlen: size_t) -> ssize_t;

}

/// Changes the given fd to blocking mode.

pub fn set_blocking_fd(fd: RawFd) -> io::Result<()> {

    let flags = unsafe { libc::fcntl(fd, libc::F_GETFL) };

    if flags < 0 {

        return Err(io::Error::last_os_error());

    }

    let r = unsafe { libc::fcntl(fd, libc::F_SETFL, flags & !libc::O_NONBLOCK) };

    if r < 0 {

        return Err(io::Error::last_os_error())

    }

    Ok(())

}

/// Sends file descriptors via the given socket.

pub fn send_raw_fds(sock_fd: RawFd, fds: &[RawFd]) -> io::Result<()> {

    let r = unsafe { sendfds(sock_fd, fds.as_ptr(), fds.len() as size_t) };

    if r < 0 {

        return Err(io::Error::last_os_error());

    }

    Ok(())

}