Add macro for checking type of entry point

Author: GabrielMajeri

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "uefi"
-version = "0.3.0"
+version = "0.3.1"
 authors = ["Gabriel Majeri <[email protected]>"]
 readme = "README.md"
 edition = "2018"
@@ -25,7 +25,7 @@ logger = []
 bitflags = "1.1.0"
 log = { version = "0.4.8", default-features = false }
 ucs2 = "0.1.0"
-uefi-macros = "0.2.0"
+uefi-macros = "0.2.1"
 
 [workspace]
 members = [

src/prelude.rs

@@ -2,9 +2,12 @@
 //!
 //! This includes the system table types, `Status` codes, etc.
 
-pub use crate::{ResultExt, Status};
+pub use crate::{Handle, ResultExt, Status};
 
 // Import the basic table types.
 pub use crate::table::boot::BootServices;
 pub use crate::table::runtime::RuntimeServices;
 pub use crate::table::{Boot, SystemTable};
+
+// Import the macro for creating the custom entry point.
+pub use uefi_macros::entry;

uefi-macros/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "uefi-macros"
-version = "0.2.0"
+version = "0.2.1"
 authors = ["Hadrien G. <[email protected]>"]
 edition = "2018"
 description = "Procedural macros for the uefi-rs crate"

uefi-macros/src/lib.rs

@@ -5,7 +5,7 @@ extern crate proc_macro;
 use proc_macro::TokenStream;
 use quote::{quote, TokenStreamExt};
 use syn::parse::{Parse, ParseStream};
-use syn::{parse_macro_input, DeriveInput, Generics, Ident, ItemType, LitStr};
+use syn::{parse_macro_input, DeriveInput, Generics, Ident, ItemFn, ItemType, LitStr};
 
 /// Parses a type definition, extracts its identifier and generic parameters
 struct TypeDefinition {
@@ -123,3 +123,25 @@ pub fn derive_protocol(item: TokenStream) -> TokenStream {
     };
     result.into()
 }
+
+/// Custom attribute for a UEFI executable entrypoint
+#[proc_macro_attribute]
+pub fn entry(args: TokenStream, input: TokenStream) -> TokenStream {
+    // This code is inspired by the approach in this embedded Rust crate:
+    // https://github.com/rust-embedded/cortex-m-rt/blob/965bf1e3291571e7e3b34834864117dc020fb391/macros/src/lib.rs#L85
+
+    if !args.is_empty() {
+        panic!("This attribute accepts no arguments");
+    }
+
+    let f = parse_macro_input!(input as ItemFn);
+
+    let entry_fn_ident = &f.sig.ident;
+
+    let result = quote!(
+        static _UEFI_ENTRY_POINT_TYPE_CHECK: extern "win64" fn(uefi::Handle, uefi::table::SystemTable<uefi::table::Boot>) -> uefi::Status = #entry_fn_ident;
+        #[no_mangle]
+        pub extern "win64" #f
+    );
+    result.into()
+}

uefi-test-runner/src/main.rs

@@ -20,8 +20,8 @@ mod proto;
 #[no_mangle]
 pub static _fltused: u32 = 0;
 
-#[no_mangle]
-pub extern "C" fn efi_main(image: uefi::Handle, st: SystemTable<Boot>) -> Status {
+#[entry]
+fn efi_main(image: Handle, st: SystemTable<Boot>) -> Status {
     // Initialize utilities (logging, memory allocation...)
     uefi_services::init(&st).expect_success("Failed to initialize utilities");