build.rs

// build.rs

use bootloader::{BootConfig, 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 mut disk_builder = DiskImageBuilder::new(PathBuf::from(kernel_path));

    // Configure framebuffer resolution from environment variables
    // Default: 1920x1080 (16:9, Full HD) - most widely supported by QEMU's UEFI GOP
    // Note: 1920x1200 (16:10) is NOT available in QEMU's virtio-vga GOP mode list,
    // causing fallback to 1280x800. Use 1920x1080 for reliable high-res graphics.
    let fb_width: u64 = env::var("BREENIX_FB_WIDTH")
        .ok()
        .and_then(|s| s.parse().ok())
        .unwrap_or(1920);
    let fb_height: u64 = env::var("BREENIX_FB_HEIGHT")
        .ok()
        .and_then(|s| s.parse().ok())
        .unwrap_or(1080);

    let mut boot_config = BootConfig::default();
    boot_config.frame_buffer.minimum_framebuffer_width = Some(fb_width);
    boot_config.frame_buffer.minimum_framebuffer_height = Some(fb_height);
    disk_builder.set_boot_config(&boot_config);

    // specify output paths
    let out_dir = PathBuf::from(env::var("OUT_DIR").unwrap());
    let uefi_path = out_dir.join("breenix-uefi.img");
    let bios_path = out_dir.join("breenix-bios.img");

    // Only create the UEFI image by default. BIOS image can be enabled via env var.
    disk_builder
        .create_uefi_image(&uefi_path)
        .expect("failed to create UEFI disk image");

    let build_bios = env::var("BREENIX_BUILD_BIOS").is_ok();
    if build_bios {
        // New bootloader API removed BIOS builder; use UEFI image as placeholder to keep API surface stable.
        // If BIOS support is needed, switch to a branch that still exposes create_bios_image or vendor our own.
        disk_builder
            .create_uefi_image(&bios_path)
            .expect("failed to create BIOS placeholder image");
    }

    // 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());
}