Print something to the screen

Cargo.lock

@@ -132,6 +132,7 @@ version = "0.1.0"
 dependencies = [
  "bootloader",
  "kernel",
+ "ovmf-prebuilt",
 ]
 
 [[package]]
@@ -495,6 +496,12 @@ version = "2.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2dffe52ecf27772e601905b7522cb4ef790d2cc203488bbd0e2fe85fcb74566d"
 
+[[package]]
+name = "ovmf-prebuilt"
+version = "0.1.0-alpha.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fa50141d081512ab30fd9e7e7692476866df5098b028536ad6680212e717fa8d"
+
 [[package]]
 name = "parking"
 version = "2.1.0"

Cargo.toml

@@ -2,10 +2,14 @@
 name = "blog_os"
 version = "0.1.0"
 edition = "2021"
+default-run = "blog_os"
 
 [workspace]
 members = ["kernel"]
 
 [dependencies]
+ovmf-prebuilt = "0.1.0-alpha"
+
+[build-dependencies]
 kernel = { path = "kernel", artifact = "bin", target = "x86_64-unknown-none" }
 bootloader = "0.11.3"

build.rs

@@ -0,0 +1,21 @@
+use bootloader::DiskImageBuilder;
+use std::{env, path::PathBuf};
+
+fn main() {
+    // set by cargo for the kernel artifact dependency
+    let kernel_path = env::var("CARGO_BIN_FILE_KERNEL").unwrap();
+    let disk_builder = DiskImageBuilder::new(PathBuf::from(kernel_path));
+
+    // specify output paths
+    let out_dir = PathBuf::from(env::var("OUT_DIR").unwrap());
+    let uefi_path = out_dir.join("blog_os-uefi.img");
+    let bios_path = out_dir.join("blog_os-bios.img");
+
+    // create the disk images
+    disk_builder.create_uefi_image(&uefi_path).unwrap();
+    disk_builder.create_bios_image(&bios_path).unwrap();
+
+    // pass the disk image paths via environment variables
+    println!("cargo:rustc-env=UEFI_IMAGE={}", uefi_path.display());
+    println!("cargo:rustc-env=BIOS_IMAGE={}", bios_path.display());
+}

kernel/Cargo.toml

@@ -3,7 +3,10 @@ name = "kernel"
 version = "0.1.0"
 edition = "2021"
 
-# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+[[bin]]
+name = "kernel"
+test = false
+bench = false
 
 [dependencies]
 bootloader_api = "0.11.0"

kernel/src/main.rs

@@ -3,9 +3,18 @@
 
 use core::panic::PanicInfo;
 
+use bootloader_api::BootInfo;
+
 bootloader_api::entry_point!(kernel_main);
 
-fn kernel_main(_bootinfo: &'static mut bootloader_api::BootInfo) -> ! {
+fn kernel_main(boot_info: &'static mut BootInfo) -> ! {
+    if let Some(framebuffer) = boot_info.framebuffer.as_mut() {
+        let mut value = 0x90;
+        for byte in framebuffer.buffer_mut() {
+            *byte = value;
+            value = value.wrapping_add(1);
+        }
+    }
     loop {}
 }
 

src/bin/qemu-bios.rs

@@ -0,0 +1,12 @@
+use std::{
+    env,
+    process::{self, Command},
+};
+
+fn main() {
+    let mut qemu = Command::new("qemu-system-x86_64");
+    qemu.arg("-drive");
+    qemu.arg(format!("format=raw,file={}", env!("BIOS_IMAGE")));
+    let exit_status = qemu.status().unwrap();
+    process::exit(exit_status.code().unwrap_or(-1));
+}

src/bin/qemu-uefi.rs

@@ -0,0 +1,13 @@
+use std::{
+    env,
+    process::{self, Command},
+};
+
+fn main() {
+    let mut qemu = Command::new("qemu-system-x86_64");
+    qemu.arg("-drive");
+    qemu.arg(format!("format=raw,file={}", env!("UEFI_IMAGE")));
+    qemu.arg("-bios").arg(ovmf_prebuilt::ovmf_pure_efi());
+    let exit_status = qemu.status().unwrap();
+    process::exit(exit_status.code().unwrap_or(-1));
+}

src/main.rs

@@ -1,21 +1,13 @@
-use bootloader::DiskImageBuilder;
-use std::{env, error::Error, path::PathBuf};
+use std::{env, fs};
 
-fn main() -> Result<(), Box<dyn Error>> {
-    // set by cargo for the kernel artifact dependency
-    let kernel_path = PathBuf::from(env!("CARGO_BIN_FILE_KERNEL"));
-    let disk_builder = DiskImageBuilder::new(kernel_path);
+fn main() {
+    let current_exe = env::current_exe().unwrap();
+    let uefi_target = current_exe.with_file_name("uefi.img");
+    let bios_target = current_exe.with_file_name("bios.img");
 
-    // place the disk image files under target/debug or target/release
-    let target_dir = env::current_exe()?;
+    fs::copy(env!("UEFI_IMAGE"), &uefi_target).unwrap();
+    fs::copy(env!("BIOS_IMAGE"), &bios_target).unwrap();
 
-    let uefi_path = target_dir.with_file_name("blog_os-uefi.img");
-    disk_builder.create_uefi_image(&uefi_path)?;
-    println!("Created UEFI disk image at {}", uefi_path.display());
-
-    let bios_path = target_dir.with_file_name("blog_os-bios.img");
-    disk_builder.create_bios_image(&bios_path)?;
-    println!("Created BIOS disk image at {}", bios_path.display());
-
-    Ok(())
+    println!("UEFI disk image at {}", uefi_target.display());
+    println!("BIOS disk image at {}", bios_target.display());
 }