//! Helper functions for `prctl` syscalls.

#![allow(unsafe_code)]

use crate::backend::prctl::syscalls;

use crate::ffi::{c_int, c_void};

use crate::io;

use crate::utils::as_mut_ptr;

use bitflags::bitflags;

use core::mem::MaybeUninit;

use core::ptr::null_mut;

#[cfg(linux_raw_dep)]

bitflags! {

    /// `PR_PAC_AP*`

    #[repr(transparent)]

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

    pub struct PointerAuthenticationKeys: u32 {

        /// `PR_PAC_APIAKEY`—Instruction authentication key `A`.

        const INSTRUCTION_AUTHENTICATION_KEY_A = linux_raw_sys::prctl::PR_PAC_APIAKEY;

        /// `PR_PAC_APIBKEY`—Instruction authentication key `B`.

        const INSTRUCTION_AUTHENTICATION_KEY_B = linux_raw_sys::prctl::PR_PAC_APIBKEY;

        /// `PR_PAC_APDAKEY`—Data authentication key `A`.

        const DATA_AUTHENTICATION_KEY_A = linux_raw_sys::prctl::PR_PAC_APDAKEY;

        /// `PR_PAC_APDBKEY`—Data authentication key `B`.

        const DATA_AUTHENTICATION_KEY_B = linux_raw_sys::prctl::PR_PAC_APDBKEY;

        /// `PR_PAC_APGAKEY`—Generic authentication `A` key.

        const GENERIC_AUTHENTICATION_KEY_A = linux_raw_sys::prctl::PR_PAC_APGAKEY;

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

        const _ = !0;

    }

}

#[inline]

pub(crate) unsafe fn prctl_1arg(option: c_int) -> io::Result<c_int> {

    const NULL: *mut c_void = null_mut();

    syscalls::prctl(option, NULL, NULL, NULL, NULL)

}

#[inline]

pub(crate) unsafe fn prctl_2args(option: c_int, arg2: *mut c_void) -> io::Result<c_int> {

    const NULL: *mut c_void = null_mut();

    syscalls::prctl(option, arg2, NULL, NULL, NULL)

}

#[inline]

pub(crate) unsafe fn prctl_3args(

    option: c_int,

    arg2: *mut c_void,

    arg3: *mut c_void,

) -> io::Result<c_int> {

    syscalls::prctl(option, arg2, arg3, null_mut(), null_mut())

}

#[inline]

pub(crate) unsafe fn prctl_get_at_arg2_optional<P>(option: i32) -> io::Result<P> {

    let mut value: MaybeUninit<P> = MaybeUninit::uninit();

    prctl_2args(option, value.as_mut_ptr().cast())?;

    Ok(value.assume_init())

}

#[inline]

pub(crate) unsafe fn prctl_get_at_arg2<P, T>(option: i32) -> io::Result<T>

where

    P: Default,

    T: TryFrom<P, Error = io::Errno>,

{

    let mut value: P = Default::default();

    prctl_2args(option, as_mut_ptr(&mut value).cast())?;

    TryFrom::try_from(value)

}