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//! Implements typical patterns for `ioctl` usage.
use super::{Ioctl, IoctlOutput, Opcode, RawOpcode};
use crate::backend::c;
use crate::io::Result;
use core::marker::PhantomData;
use core::ptr::addr_of_mut;
use core::{fmt, mem};
/// Implements an `ioctl` with no real arguments.
pub struct NoArg<Opcode> {
/// The opcode.
_opcode: PhantomData<Opcode>,
}
impl<Opcode: CompileTimeOpcode> fmt::Debug for NoArg<Opcode> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_tuple("NoArg").field(&Opcode::OPCODE).finish()
}
}
impl<Opcode: CompileTimeOpcode> NoArg<Opcode> {
/// Create a new no-argument `ioctl` object.
///
/// # Safety
///
/// - `Opcode` must provide a valid opcode.
#[inline]
pub unsafe fn new() -> Self {
Self {
_opcode: PhantomData,
}
}
}
unsafe impl<Opcode: CompileTimeOpcode> Ioctl for NoArg<Opcode> {
type Output = ();
const IS_MUTATING: bool = false;
const OPCODE: self::Opcode = Opcode::OPCODE;
fn as_ptr(&mut self) -> *mut c::c_void {
core::ptr::null_mut()
}
unsafe fn output_from_ptr(_: IoctlOutput, _: *mut c::c_void) -> Result<Self::Output> {
Ok(())
}
}
/// Implements the traditional “getter” pattern for `ioctl`s.
///
/// Some `ioctl`s just read data into the userspace. As this is a popular
/// pattern this structure implements it.
pub struct Getter<Opcode, Output> {
/// The output data.
output: mem::MaybeUninit<Output>,
/// The opcode.
_opcode: PhantomData<Opcode>,
}
impl<Opcode: CompileTimeOpcode, Output> fmt::Debug for Getter<Opcode, Output> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_tuple("Getter").field(&Opcode::OPCODE).finish()
}
}
impl<Opcode: CompileTimeOpcode, Output> Getter<Opcode, Output> {
/// Create a new getter-style `ioctl` object.
///
/// # Safety
///
/// - `Opcode` must provide a valid opcode.
/// - For this opcode, `Output` must be the type that the kernel expects to
/// write into.
#[inline]
pub unsafe fn new() -> Self {
Self {
output: mem::MaybeUninit::uninit(),
_opcode: PhantomData,
}
}
}
unsafe impl<Opcode: CompileTimeOpcode, Output> Ioctl for Getter<Opcode, Output> {
type Output = Output;
const IS_MUTATING: bool = true;
const OPCODE: self::Opcode = Opcode::OPCODE;
fn as_ptr(&mut self) -> *mut c::c_void {
self.output.as_mut_ptr().cast()
}
unsafe fn output_from_ptr(_: IoctlOutput, ptr: *mut c::c_void) -> Result<Self::Output> {
Ok(ptr.cast::<Output>().read())
}
}
/// Implements the pattern for `ioctl`s where a pointer argument is given to
/// the `ioctl`.
///
/// The opcode must be read-only.
pub struct Setter<Opcode, Input> {
/// The input data.
input: Input,
/// The opcode.
_opcode: PhantomData<Opcode>,
}
impl<Opcode: CompileTimeOpcode, Input: fmt::Debug> fmt::Debug for Setter<Opcode, Input> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_tuple("Setter")
.field(&Opcode::OPCODE)
.field(&self.input)
.finish()
}
}
impl<Opcode: CompileTimeOpcode, Input> Setter<Opcode, Input> {
/// Create a new pointer setter-style `ioctl` object.
///
/// # Safety
///
/// - `Opcode` must provide a valid opcode.
/// - For this opcode, `Input` must be the type that the kernel expects to
/// get.
#[inline]
pub unsafe fn new(input: Input) -> Self {
Self {
input,
_opcode: PhantomData,
}
}
}
unsafe impl<Opcode: CompileTimeOpcode, Input> Ioctl for Setter<Opcode, Input> {
type Output = ();
const IS_MUTATING: bool = false;
const OPCODE: self::Opcode = Opcode::OPCODE;
fn as_ptr(&mut self) -> *mut c::c_void {
addr_of_mut!(self.input).cast::<c::c_void>()
}
unsafe fn output_from_ptr(_: IoctlOutput, _: *mut c::c_void) -> Result<Self::Output> {
Ok(())
}
}
/// Implements an “updater” pattern for `ioctl`s.
///
/// The ioctl takes a reference to a struct that it reads its input from,
/// then writes output to the same struct.
pub struct Updater<'a, Opcode, Value> {
/// Reference to input/output data.
value: &'a mut Value,
/// The opcode.
_opcode: PhantomData<Opcode>,
}
impl<'a, Opcode: CompileTimeOpcode, Value> Updater<'a, Opcode, Value> {
/// Create a new pointer updater-style `ioctl` object.
///
/// # Safety
///
/// - `Opcode` must provide a valid opcode.
/// - For this opcode, `Value` must be the type that the kernel expects to
/// get.
#[inline]
pub unsafe fn new(value: &'a mut Value) -> Self {
Self {
value,
_opcode: PhantomData,
}
}
}
unsafe impl<'a, Opcode: CompileTimeOpcode, T> Ioctl for Updater<'a, Opcode, T> {
type Output = ();
const IS_MUTATING: bool = true;
const OPCODE: self::Opcode = Opcode::OPCODE;
fn as_ptr(&mut self) -> *mut c::c_void {
(self.value as *mut T).cast()
}
unsafe fn output_from_ptr(_output: IoctlOutput, _ptr: *mut c::c_void) -> Result<()> {
Ok(())
}
}
/// Trait for something that provides an `ioctl` opcode at compile time.
pub trait CompileTimeOpcode {
/// The opcode.
const OPCODE: Opcode;
}
/// Provides a bad opcode at compile time.
pub struct BadOpcode<const OPCODE: RawOpcode>;
impl<const OPCODE: RawOpcode> CompileTimeOpcode for BadOpcode<OPCODE> {
const OPCODE: Opcode = Opcode::old(OPCODE);
}
/// Provides a read code at compile time.
///
/// This corresponds to the C macro `_IOR(GROUP, NUM, Data)`.
#[cfg(any(linux_kernel, bsd))]
pub struct ReadOpcode<const GROUP: u8, const NUM: u8, Data>(Data);
#[cfg(any(linux_kernel, bsd))]
impl<const GROUP: u8, const NUM: u8, Data> CompileTimeOpcode for ReadOpcode<GROUP, NUM, Data> {
const OPCODE: Opcode = Opcode::read::<Data>(GROUP, NUM);
}
/// Provides a write code at compile time.
///
/// This corresponds to the C macro `_IOW(GROUP, NUM, Data)`.
#[cfg(any(linux_kernel, bsd))]
pub struct WriteOpcode<const GROUP: u8, const NUM: u8, Data>(Data);
#[cfg(any(linux_kernel, bsd))]
impl<const GROUP: u8, const NUM: u8, Data> CompileTimeOpcode for WriteOpcode<GROUP, NUM, Data> {
const OPCODE: Opcode = Opcode::write::<Data>(GROUP, NUM);
}
/// Provides a read/write code at compile time.
///
/// This corresponds to the C macro `_IOWR(GROUP, NUM, Data)`.
#[cfg(any(linux_kernel, bsd))]
pub struct ReadWriteOpcode<const GROUP: u8, const NUM: u8, Data>(Data);
#[cfg(any(linux_kernel, bsd))]
impl<const GROUP: u8, const NUM: u8, Data> CompileTimeOpcode for ReadWriteOpcode<GROUP, NUM, Data> {
const OPCODE: Opcode = Opcode::read_write::<Data>(GROUP, NUM);
}
/// Provides a `None` code at compile time.
///
/// This corresponds to the C macro `_IO(GROUP, NUM)` when `Data` is zero
/// sized.
#[cfg(any(linux_kernel, bsd))]
pub struct NoneOpcode<const GROUP: u8, const NUM: u8, Data>(Data);
#[cfg(any(linux_kernel, bsd))]
impl<const GROUP: u8, const NUM: u8, Data> CompileTimeOpcode for NoneOpcode<GROUP, NUM, Data> {
const OPCODE: Opcode = Opcode::none::<Data>(GROUP, NUM);
}