feat(uefi): read application from file system

Cargo.toml

@@ -35,7 +35,7 @@ exclusive_cell = "0.1"
 spinning_top = "0.3"
 
 [target.'cfg(target_os = "uefi")'.dependencies]
-uefi = "0.26"
+uefi = { version = "0.26", features = ["alloc"] }
 uefi-services = { version = "0.23", features = ["qemu"] }
 qemu-exit = "3"
 

src/macros.rs

@@ -3,28 +3,40 @@
 /// Adapted from [`std::print`].
 ///
 /// [`std::print`]: https://doc.rust-lang.org/stable/std/macro.print.html
-#[cfg(target_os = "none")]
 #[macro_export]
 macro_rules! print {
-    ($($arg:tt)*) => {{
-        $crate::_print(::core::format_args!($($arg)*));
-    }};
+    ($($arg:tt)*) => {
+        #[cfg(target_os = "none")]
+        {
+            $crate::_print(::core::format_args!($($arg)*));
+        }
+        #[cfg(target_os = "uefi")]
+        {
+            ::uefi_services::print!($($arg)*);
+        }
+    };
 }
 
 /// Prints to the standard output, with a newline.
 ///
 /// Adapted from [`std::println`].
 ///
 /// [`std::println`]: https://doc.rust-lang.org/stable/std/macro.println.html
-#[cfg(target_os = "none")]
 #[macro_export]
 macro_rules! println {
     () => {
         $crate::print!("\n")
     };
-    ($($arg:tt)*) => {{
-        $crate::_print(::core::format_args!("{}\n", format_args!($($arg)*)));
-    }};
+    ($($arg:tt)*) => {
+        #[cfg(target_os = "none")]
+        {
+            $crate::_print(::core::format_args!("{}\n", format_args!($($arg)*)));
+        }
+        #[cfg(target_os = "uefi")]
+        {
+            ::uefi_services::println!($($arg)*);
+        }
+    };
 }
 
 /// Prints and returns the value of a given expression for quick and dirty

src/main.rs

@@ -20,7 +20,10 @@ mod none;
 #[cfg(target_os = "uefi")]
 mod uefi;
 
-#[cfg(all(target_arch = "x86_64", target_os = "none", not(feature = "fc")))]
+#[cfg(any(
+	target_os = "uefi",
+	all(target_arch = "x86_64", target_os = "none", not(feature = "fc"))
+))]
 extern crate alloc;
 
 #[cfg(target_os = "none")]

src/uefi.rs

@@ -1,12 +1,36 @@
+use alloc::string::String;
+use alloc::vec::Vec;
+
 use qemu_exit::QEMUExit;
+use uefi::fs::{FileSystem, Path};
 use uefi::prelude::*;
 
+fn read_app(bt: &BootServices) -> Vec<u8> {
+	let fs = bt
+		.get_image_file_system(bt.image_handle())
+		.expect("should open file system");
+
+	let path = Path::new(cstr16!(r"\efi\boot\hermit-app"));
+
+	let data = FileSystem::new(fs)
+		.read(path)
+		.expect("should read file content");
+
+	let len = data.len();
+	log::info!("Read Hermit application from \"{path}\" (size = {len} B)");
+
+	data
+}
+
 // Entry Point of the Uefi Loader
 #[entry]
 fn loader_main(_handle: Handle, mut system_table: SystemTable<Boot>) -> Status {
 	uefi_services::init(&mut system_table).unwrap();
 
-	log::info!("Hello, UEFI!");
+	let app = read_app(system_table.boot_services());
+
+	let string = String::from_utf8(app).unwrap();
+	println!("{string}");
 
 	let custom_exit_success = 3;
 	let qemu_exit_handle = qemu_exit::X86::new(0xf4, custom_exit_success);

xtask/src/ci/qemu.rs

@@ -49,6 +49,7 @@ impl Qemu {
 
 			sh.create_dir("target/esp/efi/boot")?;
 			sh.copy_file(self.build.dist_object(), "target/esp/efi/boot/bootx64.efi")?;
+			sh.write_file("target/esp/efi/boot/hermit-app", "Hello, UEFI!\n")?;
 		}
 
 		let target = self.build.target();