0184-QEMU 调试程序

环境

• Time 2022-11-13
• WSL-Ubuntu 22.04
• QEMU 6.2.0
• Rust 1.67.0-nightly

前言

说明

参考：https://os.phil-opp.com/minimal-rust-kernel

目标

将上一节编写的可执行文件制作成 QEMU 可以启动的镜像，并使用 QEMU 调试。

main.rs

#![no_std]
#![no_main]

static HELLO: &[u8] = b"Hello World!";

#[no_mangle]
pub extern "C" fn _start() -> ! {
    let vga_buffer = 0xb8000 as *mut u8;

    for (i, &byte) in HELLO.iter().enumerate() {
        unsafe {
            *vga_buffer.offset(i as isize * 2) = byte;
            *vga_buffer.offset(i as isize * 2 + 1) = 0xb;
        }
    }

    loop {}
}

#[panic_handler]
fn panic(_info: &core::panic::PanicInfo) -> ! {
    loop {}
}

Cargo.toml

[package]
edition = "2021"
name = "mos"
version = "0.1.0"

[dependencies]
bootloader = "0.9.8"

制作镜像

安装命令：cargo install bootimage
构建命令：cargo bootimage

root@jiangbo12490:~/git/game# cargo install bootimage
    Blocking waiting for file lock on package cache
    Updating crates.io index
     Ignored package `bootimage v0.10.3` is already installed, use --force to override
root@jiangbo12490:~/git/game# cargo bootimage
WARNING: `CARGO_MANIFEST_DIR` env variable not set
Building kernel
   Compiling mos v0.1.0 (/root/git/game)
    Finished dev [unoptimized + debuginfo] target(s) in 0.27s
Building bootloader
   Compiling bootloader v0.9.23 (/root/.cargo/registry/src/github.com-1ecc6299db9ec823/bootloader-0.9.23)
    Finished release [optimized + debuginfo] target(s) in 0.57s
Created bootimage for `mos` at `/root/git/game/target/mos/debug/bootimage-mos.bin`

启动 QEMU 脚本

#! /usr/bin/bash

cargo bootimage
qemu-system-x86_64 -drive format=raw,file=target/mos/debug/bootimage-mos.bin \
    -display curses -s -S

GDB 调试脚本

#! /usr/bin/bash

gdb target/mos/debug/mos \
    -ex "target remote localhost:1234" \
    -ex "break _start" -ex "continue"

文件目录结构

├── Cargo.lock
├── Cargo.toml
├── gdb.sh
├── mos.json
├── qemu.sh
├── rust-toolchain
├── src
│   └── main.rs
└── .cargo
    └── config.toml

效果

总结

使用 Rust 编写了一个在 x64 平台上的独立可执行程序，并且使用 QEMU 运行和 GDB 调试。

附录