// SPDX-License-Identifier: GPL-2.0
//! Crate for all kernel procedural macros.
#[macro_use]
mod quote;
mod concat_idents;
mod helpers;
mod module;
mod paste;
mod pin_data;
mod pinned_drop;
mod vtable;
mod zeroable;
use proc_macro::TokenStream;
/// Declares a kernel module.
///
/// The `type` argument should be a type which implements the [`Module`]
/// trait. Also accepts various forms of kernel metadata.
///
/// C header: [`include/linux/moduleparam.h`](srctree/include/linux/moduleparam.h)
///
/// [`Module`]: ../kernel/trait.Module.html
///
/// # Examples
///
/// ```ignore
/// use kernel::prelude::*;
///
/// module!{
/// type: MyModule,
/// name: "my_kernel_module",
/// author: "Rust for Linux Contributors",
/// description: "My very own kernel module!",
/// license: "GPL",
/// alias: ["alternate_module_name"],
/// }
///
/// struct MyModule;
///
/// impl kernel::Module for MyModule {
/// fn init() -> Result<Self> {
/// // If the parameter is writeable, then the kparam lock must be
/// // taken to read the parameter:
/// {
/// let lock = THIS_MODULE.kernel_param_lock();
/// pr_info!("i32 param is: {}\n", writeable_i32.read(&lock));
/// }
/// // If the parameter is read only, it can be read without locking
/// // the kernel parameters:
/// pr_info!("i32 param is: {}\n", my_i32.read());
/// Ok(Self)
/// }
/// }
/// ```
///
/// ## Firmware
///
/// The following example shows how to declare a kernel module that needs
/// to load binary firmware files. You need to specify the file names of
/// the firmware in the `firmware` field. The information is embedded
/// in the `modinfo` section of the kernel module. For example, a tool to
/// build an initramfs uses this information to put the firmware files into
/// the initramfs image.
///
/// ```ignore
/// use kernel::prelude::*;
///
/// module!{
/// type: MyDeviceDriverModule,
/// name: "my_device_driver_module",
/// author: "Rust for Linux Contributors",
/// description: "My device driver requires firmware",
/// license: "GPL",
/// firmware: ["my_device_firmware1.bin", "my_device_firmware2.bin"],
/// }
///
/// struct MyDeviceDriverModule;
///
/// impl kernel::Module for MyDeviceDriverModule {
/// fn init() -> Result<Self> {
/// Ok(Self)
/// }
/// }
/// ```
///
/// # Supported argument types
/// - `type`: type which implements the [`Module`] trait (required).
/// - `name`: ASCII string literal of the name of the kernel module (required).
/// - `author`: string literal of the author of the kernel module.
/// - `description`: string literal of the description of the kernel module.
/// - `license`: ASCII string literal of the license of the kernel module (required).
/// - `alias`: array of ASCII string literals of the alias names of the kernel module.
/// - `firmware`: array of ASCII string literals of the firmware files of
/// the kernel module.
#[proc_macro]
pub fn module(ts: TokenStream) -> TokenStream {
module::module(ts)
}
/// Declares or implements a vtable trait.
///
/// Linux's use of pure vtables is very close to Rust traits, but they differ
/// in how unimplemented functions are represented. In Rust, traits can provide
/// default implementation for all non-required methods (and the default
/// implementation could just return `Error::EINVAL`); Linux typically use C
/// `NULL` pointers to represent these functions.
///
/// This attribute closes that gap. A trait can be annotated with the
/// `#[vtable]` attribute. Implementers of the trait will then also have to
/// annotate the trait with `#[vtable]`. This attribute generates a `HAS_*`
/// associated constant bool for each method in the trait that is set to true if
/// the implementer has overridden the associated method.
///
/// For a trait method to be optional, it must have a default implementation.
/// This is also the case for traits annotated with `#[vtable]`, but in this
/// case the default implementation will never be executed. The reason for this
/// is that the functions will be called through function pointers installed in
/// C side vtables. When an optional method is not implemented on a `#[vtable]`
/// trait, a NULL entry is installed in the vtable. Thus the default
/// implementation is never called. Since these traits are not designed to be
/// used on the Rust side, it should not be possible to call the default
/// implementation. This is done to ensure that we call the vtable methods
/// through the C vtable, and not through the Rust vtable. Therefore, the
/// default implementation should call `kernel::build_error`, which prevents
/// calls to this function at compile time:
///
/// ```compile_fail
/// # use kernel::error::VTABLE_DEFAULT_ERROR;
/// kernel::build_error(VTABLE_DEFAULT_ERROR)
/// ```
///
/// Note that you might need to import [`kernel::error::VTABLE_DEFAULT_ERROR`].
///
/// This macro should not be used when all functions are required.
///
/// # Examples
///
/// ```ignore
/// use kernel::error::VTABLE_DEFAULT_ERROR;
/// use kernel::prelude::*;
///
/// // Declares a `#[vtable]` trait
/// #[vtable]
/// pub trait Operations: Send + Sync + Sized {
/// fn foo(&self) -> Result<()> {
/// kernel::build_error(VTABLE_DEFAULT_ERROR)
/// }
///
/// fn bar(&self) -> Result<()> {
/// kernel::build_error(VTABLE_DEFAULT_ERROR)
/// }
/// }
///
/// struct Foo;
///
/// // Implements the `#[vtable]` trait
/// #[vtable]
/// impl Operations for Foo {
/// fn foo(&self) -> Result<()> {
/// # Err(EINVAL)
/// // ...
/// }
/// }
///
/// assert_eq!(<Foo as Operations>::HAS_FOO, true);
/// assert_eq!(<Foo as Operations>::HAS_BAR, false);
/// ```
///
/// [`kernel::error::VTABLE_DEFAULT_ERROR`]: ../kernel/error/constant.VTABLE_DEFAULT_ERROR.html
#[proc_macro_attribute]
pub fn vtable(attr: TokenStream, ts: TokenStream) -> TokenStream {
vtable::vtable(attr, ts)
}
/// Concatenate two identifiers.
///
/// This is useful in macros that need to declare or reference items with names
/// starting with a fixed prefix and ending in a user specified name. The resulting
/// identifier has the span of the second argument.
///
/// # Examples
///
/// ```ignore
/// use kernel::macro::concat_idents;
///
/// macro_rules! pub_no_prefix {
/// ($prefix:ident, $($newname:ident),+) => {
/// $(pub(crate) const $newname: u32 = kernel::macros::concat_idents!($prefix, $newname);)+
/// };
/// }
///
/// pub_no_prefix!(
/// binder_driver_return_protocol_,
/// BR_OK,
/// BR_ERROR,
/// BR_TRANSACTION,
/// BR_REPLY,
/// BR_DEAD_REPLY,
/// BR_TRANSACTION_COMPLETE,
/// BR_INCREFS,
/// BR_ACQUIRE,
/// BR_RELEASE,
/// BR_DECREFS,
/// BR_NOOP,
/// BR_SPAWN_LOOPER,
/// BR_DEAD_BINDER,
/// BR_CLEAR_DEATH_NOTIFICATION_DONE,
/// BR_FAILED_REPLY
/// );
///
/// assert_eq!(BR_OK, binder_driver_return_protocol_BR_OK);
/// ```
#[proc_macro]
pub fn concat_idents(ts: TokenStream) -> TokenStream {
concat_idents::concat_idents(ts)
}
/// Used to specify the pinning information of the fields of a struct.
///
/// This is somewhat similar in purpose as
/// [pin-project-lite](https://crates.io/crates/pin-project-lite).
/// Place this macro on a struct definition and then `#[pin]` in front of the attributes of each
/// field you want to structurally pin.
///
/// This macro enables the use of the [`pin_init!`] macro. When pin-initializing a `struct`,
/// then `#[pin]` directs the type of initializer that is required.
///
/// If your `struct` implements `Drop`, then you need to add `PinnedDrop` as arguments to this
/// macro, and change your `Drop` implementation to `PinnedDrop` annotated with
/// `#[`[`macro@pinned_drop`]`]`, since dropping pinned values requires extra care.
///
/// # Examples
///
/// ```rust,ignore
/// #[pin_data]
/// struct DriverData {
/// #[pin]
/// queue: Mutex<Vec<Command>>,
/// buf: Box<[u8; 1024 * 1024]>,
/// }
/// ```
///
/// ```rust,ignore
/// #[pin_data(PinnedDrop)]
/// struct DriverData {
/// #[pin]
/// queue: Mutex<Vec<Command>>,
/// buf: Box<[u8; 1024 * 1024]>,
/// raw_info: *mut Info,
/// }
///
/// #[pinned_drop]
/// impl PinnedDrop for DriverData {
/// fn drop(self: Pin<&mut Self>) {
/// unsafe { bindings::destroy_info(self.raw_info) };
/// }
/// }
/// ```
///
/// [`pin_init!`]: ../kernel/macro.pin_init.html
// ^ cannot use direct link, since `kernel` is not a dependency of `macros`.
#[proc_macro_attribute]
pub fn pin_data(inner: TokenStream, item: TokenStream) -> TokenStream {
pin_data::pin_data(inner, item)
}
/// Used to implement `PinnedDrop` safely.
///
/// Only works on structs that are annotated via `#[`[`macro@pin_data`]`]`.
///
/// # Examples
///
/// ```rust,ignore
/// #[pin_data(PinnedDrop)]
/// struct DriverData {
/// #[pin]
/// queue: Mutex<Vec<Command>>,
/// buf: Box<[u8; 1024 * 1024]>,
/// raw_info: *mut Info,
/// }
///
/// #[pinned_drop]
/// impl PinnedDrop for DriverData {
/// fn drop(self: Pin<&mut Self>) {
/// unsafe { bindings::destroy_info(self.raw_info) };
/// }
/// }
/// ```
#[proc_macro_attribute]
pub fn pinned_drop(args: TokenStream, input: TokenStream) -> TokenStream {
pinned_drop::pinned_drop(args, input)
}
/// Paste identifiers together.
///
/// Within the `paste!` macro, identifiers inside `[<` and `>]` are concatenated together to form a
/// single identifier.
///
/// This is similar to the [`paste`] crate, but with pasting feature limited to identifiers and
/// literals (lifetimes and documentation strings are not supported). There is a difference in
/// supported modifiers as well.
///
/// # Example
///
/// ```ignore
/// use kernel::macro::paste;
///
/// macro_rules! pub_no_prefix {
/// ($prefix:ident, $($newname:ident),+) => {
/// paste! {
/// $(pub(crate) const $newname: u32 = [<$prefix $newname>];)+
/// }
/// };
/// }
///
/// pub_no_prefix!(
/// binder_driver_return_protocol_,
/// BR_OK,
/// BR_ERROR,
/// BR_TRANSACTION,
/// BR_REPLY,
/// BR_DEAD_REPLY,
/// BR_TRANSACTION_COMPLETE,
/// BR_INCREFS,
/// BR_ACQUIRE,
/// BR_RELEASE,
/// BR_DECREFS,
/// BR_NOOP,
/// BR_SPAWN_LOOPER,
/// BR_DEAD_BINDER,
/// BR_CLEAR_DEATH_NOTIFICATION_DONE,
/// BR_FAILED_REPLY
/// );
///
/// assert_eq!(BR_OK, binder_driver_return_protocol_BR_OK);
/// ```
///
/// # Modifiers
///
/// For each identifier, it is possible to attach one or multiple modifiers to
/// it.
///
/// Currently supported modifiers are:
/// * `span`: change the span of concatenated identifier to the span of the specified token. By
/// default the span of the `[< >]` group is used.
/// * `lower`: change the identifier to lower case.
/// * `upper`: change the identifier to upper case.
///
/// ```ignore
/// use kernel::macro::paste;
///
/// macro_rules! pub_no_prefix {
/// ($prefix:ident, $($newname:ident),+) => {
/// kernel::macros::paste! {
/// $(pub(crate) const fn [<$newname:lower:span>]: u32 = [<$prefix $newname:span>];)+
/// }
/// };
/// }
///
/// pub_no_prefix!(
/// binder_driver_return_protocol_,
/// BR_OK,
/// BR_ERROR,
/// BR_TRANSACTION,
/// BR_REPLY,
/// BR_DEAD_REPLY,
/// BR_TRANSACTION_COMPLETE,
/// BR_INCREFS,
/// BR_ACQUIRE,
/// BR_RELEASE,
/// BR_DECREFS,
/// BR_NOOP,
/// BR_SPAWN_LOOPER,
/// BR_DEAD_BINDER,
/// BR_CLEAR_DEATH_NOTIFICATION_DONE,
/// BR_FAILED_REPLY
/// );
///
/// assert_eq!(br_ok(), binder_driver_return_protocol_BR_OK);
/// ```
///
/// # Literals
///
/// Literals can also be concatenated with other identifiers:
///
/// ```ignore
/// macro_rules! create_numbered_fn {
/// ($name:literal, $val:literal) => {
/// kernel::macros::paste! {
/// fn [<some_ $name _fn $val>]() -> u32 { $val }
/// }
/// };
/// }
///
/// create_numbered_fn!("foo", 100);
///
/// assert_eq!(some_foo_fn100(), 100)
/// ```
///
/// [`paste`]: https://docs.rs/paste/
#[proc_macro]
pub fn paste(input: TokenStream) -> TokenStream {
let mut tokens = input.into_iter().collect();
paste::expand(&mut tokens);
tokens.into_iter().collect()
}
/// Derives the [`Zeroable`] trait for the given struct.
///
/// This can only be used for structs where every field implements the [`Zeroable`] trait.
///
/// # Examples
///
/// ```rust,ignore
/// #[derive(Zeroable)]
/// pub struct DriverData {
/// id: i64,
/// buf_ptr: *mut u8,
/// len: usize,
/// }
/// ```
#[proc_macro_derive(Zeroable)]
pub fn derive_zeroable(input: TokenStream) -> TokenStream {
zeroable::derive(input)
}
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