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// SPDX-License-Identifier: GPL-2.0 OR MIT
//! DRM File objects.
//!
//! C header: [`include/linux/drm/drm_file.h`](srctree/include/linux/drm/drm_file.h)
use crate::{bindings, drm, error::Result, prelude::*};
use core::marker::PhantomData;
use core::pin::Pin;
/// Trait that must be implemented by DRM drivers to represent a DRM File (a client instance).
pub trait DriverFile {
/// The parent `Driver` implementation for this `DriverFile`.
type Driver: drm::drv::Driver;
/// Open a new file (called when a client opens the DRM device).
fn open(device: &drm::device::Device<Self::Driver>) -> Result<Pin<KBox<Self>>>;
}
/// An open DRM File.
///
/// # Invariants
/// `raw` is a valid pointer to an open `drm_file` struct.
#[repr(transparent)]
pub struct File<T: DriverFile> {
raw: *mut bindings::drm_file,
_p: PhantomData<T>,
}
#[allow(clippy::missing_safety_doc)]
/// The open callback of a `struct drm_file`.
pub(super) unsafe extern "C" fn open_callback<T: DriverFile>(
raw_dev: *mut bindings::drm_device,
raw_file: *mut bindings::drm_file,
) -> core::ffi::c_int {
// SAFETY: A callback from `struct drm_driver::open` gurantees that `raw_dev` is valid
// pointer to a `sturct drm_device`.
let drm = unsafe { drm::device::Device::borrow(raw_dev) };
// SAFETY: This reference won't escape this function
let file = unsafe { &mut *raw_file };
let inner = match T::open(drm) {
Err(e) => {
return e.to_errno();
}
Ok(i) => i,
};
// SAFETY: This pointer is treated as pinned, and the Drop guarantee is upheld below.
file.driver_priv = KBox::into_raw(unsafe { Pin::into_inner_unchecked(inner) }) as *mut _;
0
}
#[allow(clippy::missing_safety_doc)]
/// The postclose callback of a `struct drm_file`.
pub(super) unsafe extern "C" fn postclose_callback<T: DriverFile>(
_raw_dev: *mut bindings::drm_device,
raw_file: *mut bindings::drm_file,
) {
// SAFETY: This reference won't escape this function
let file = unsafe { &*raw_file };
// SAFETY: `file.driver_priv` has been created in `open_callback` through `KBox::into_raw`.
unsafe {
let _ = KBox::from_raw(file.driver_priv as *mut T);
};
}
impl<T: DriverFile> File<T> {
#[doc(hidden)]
/// Not intended to be called externally, except via declare_drm_ioctls!()
///
/// # Safety
///
/// `raw_file` must be a valid pointer to an open `struct drm_file`, opened through `T::open`.
pub unsafe fn from_raw(raw_file: *mut bindings::drm_file) -> File<T> {
File {
raw: raw_file,
_p: PhantomData,
}
}
#[allow(dead_code)]
/// Return the raw pointer to the underlying `drm_file`.
pub(super) fn raw(&self) -> *const bindings::drm_file {
self.raw
}
/// Return an immutable reference to the raw `drm_file` structure.
pub(super) fn file(&self) -> &bindings::drm_file {
// SAFETY: `self.raw` is a valid pointer to a `struct drm_file`.
unsafe { &*self.raw }
}
/// Return a pinned reference to the driver file structure.
pub fn inner(&self) -> Pin<&T> {
// SAFETY: By the type invariant the pointer `self.raw` points to a valid and opened
// `struct drm_file`, hence `self.raw.driver_priv` has been properly initialized by
// `open_callback`.
unsafe { Pin::new_unchecked(&*(self.file().driver_priv as *const T)) }
}
}
impl<T: DriverFile> crate::private::Sealed for File<T> {}
/// Generic trait to allow users that don't care about driver specifics to accept any `File<T>`.
///
/// # Safety
///
/// Must only be implemented for `File<T>` and return the pointer, following the normal invariants
/// of that type.
pub unsafe trait GenericFile: crate::private::Sealed {
/// Returns the raw const pointer to the `struct drm_file`
fn raw(&self) -> *const bindings::drm_file;
/// Returns the raw mut pointer to the `struct drm_file`
fn raw_mut(&mut self) -> *mut bindings::drm_file;
}
// SAFETY: Implementation for `File<T>`, holding up its type invariants.
unsafe impl<T: DriverFile> GenericFile for File<T> {
fn raw(&self) -> *const bindings::drm_file {
self.raw
}
fn raw_mut(&mut self) -> *mut bindings::drm_file {
self.raw
}
}
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