CoonBOOT/src/main.rs

#![no_std]
#![no_main]
#![feature(alloc)]

extern crate uefi;
extern crate uefi_alloc;
extern crate uefi_exts;
extern crate uefi_logger;
extern crate uefi_services;
#[macro_use]
extern crate log;
extern crate alloc;
extern crate serde;
#[macro_use]
extern crate serde_derive;
extern crate serde_json_core;

use serde_json_core::de::from_slice;
use uefi::prelude::*;
use uefi::proto::media::file::{FileAttribute, FileMode};
use uefi::proto::media::fs::SimpleFileSystem;
use uefi_exts::BootServicesExt;

#[derive(Deserialize, Serialize)]
struct Configuration<'a> {
    pub kernel_location: &'a str,
    pub load_modules: bool,
}

impl<'a> Default for Configuration<'a> {
    fn default() -> Configuration<'a> {
        Configuration {
            kernel_location: "\\EFI\\COONBOOT\\CoonKRNL",
            load_modules: false,
        }
    }
}

#[no_mangle]
pub extern "win64" fn uefi_start(_image: uefi::Handle, table: SystemTable<Boot>) -> Status {
    let mut buf: [u8; 8000] = [0; 8000];

    uefi_services::init(&table).expect_success("Failed to initialize utilities");
    table
        .stdout()
        .reset(false)
        .expect_success("Failed to reset stdout");

    let mut config: Configuration = Default::default();

    let fs = table
        .boot_services()
        .find_protocol::<SimpleFileSystem>()
        .expect("Failed to resolve filesystem")
        .get();

    unsafe {
        let mut file = (*fs).open_volume().expect("Failed to open root").unwrap();
        let result = file.open(
            "\\EFI\\COONBOOT\\boot.json",
            FileMode::READ,
            FileAttribute::empty(),
        );
        match result {
            Ok(file) => {
                let mut file = file.unwrap();
                let result = file.read(&mut buf);
                match result {
                    Ok(size) => {
                        let size = size.unwrap();
                        if let Ok(c) = from_slice::<Configuration>(&buf[..size]) {
                            config = c;
                        } else {
                            error!("Failed to parse configuration file");
                            info!("Using default configuration instead");
                        }
                    }
                    Err(_) => {
                        error!("Failed to read configuration, file is too large");
                        info!("Using default configuration instead");
                    }
                }
            }
            Err(_) => {
                warn!("\\EFI\\COONBOOT\\boot.json not found, using default configuration");
            }
        }
    }
    if config.load_modules {
        error!("Can't load kernel modules, not supported yet");
    }

    info!("Loading kernel from {}", config.kernel_location);

    Status::SUCCESS
}