use crate::fd::OwnedFd;

use crate::process::{Pid, Signal};

use crate::{backend, ffi, io};

use backend::fd::AsFd;

bitflags::bitflags! {

    /// `PIDFD_*` flags for use with [`pidfd_open`].

    ///

    /// [`pidfd_open`]: crate::process::pidfd_open

    #[repr(transparent)]

    #[derive(Copy, Clone, Eq, PartialEq, Hash, Debug)]

    pub struct PidfdFlags: ffi::c_uint {

        /// `PIDFD_NONBLOCK`

        const NONBLOCK = backend::c::PIDFD_NONBLOCK;

        /// <https://docs.rs/bitflags/*/bitflags/#externally-defined-flags>

        const _ = !0;

    }

}

/// `syscall(SYS_pidfd_open, pid, flags)`—Creates a file descriptor for a

/// process.

///

/// # References

///  - [Linux]

///

/// [Linux]: https://man7.org/linux/man-pages/man2/pidfd_open.2.html

#[inline]

pub fn pidfd_open(pid: Pid, flags: PidfdFlags) -> io::Result<OwnedFd> {

    backend::process::syscalls::pidfd_open(pid, flags)

}

/// `syscall(SYS_pidfd_send_signal, pidfd, sig, NULL, 0)`—Send a signal to a

/// process specified by a file descriptor.

///

/// # References

///  - [Linux]

///

/// [Linux]: https://man7.org/linux/man-pages/man2/pidfd_send_signal.2.html

#[inline]

pub fn pidfd_send_signal<Fd: AsFd>(pidfd: Fd, sig: Signal) -> io::Result<()> {

    backend::process::syscalls::pidfd_send_signal(pidfd.as_fd(), sig)

}