MIT6.828课程JOS在macOS下的环境配置

本文将介绍如何在macOS下配置MIT6.828 JOS实验的环境。

写JOS以前，在网上搜寻JOS的开发环境，不少博客和文章都提到“不是32位linux就很差配置，会浪费大量时间在配置环境”上之类的论调。故前期开发直接使用了32位ubuntu系统，并作了共享文件系统，背景开一个ubuntu虚拟机进行编译。
最近实在没法忍受背景开虚拟机那恐怖的耗电量和发热量，尝试将开发环境移到macOS下，竟发现很是的简单。

Tools we need

在搭建环境以前，首先macOS上须要有如下两个工具：

• Homebrew Homebrew — The missing package manager for macOS
• MacPorts The MacPorts Project -- Home

运行JOS

• QEMU

  有了Homebrew，直接利用brew安装便可安装（自动安装依赖库）

  $brew install qemu

• 将kernel.img与fs.img放在目标目录下 （也能够在其余位置，为了下面的Makefile好写）

  .
  ├── Makefile
  ├── fs.img
  └── kernel.img

• 书写Makefile

  QEMU=/usr/local/Cellar/qemu/2.10.0/bin/qemu-system-i386 # path to qemu
  run:
    $(QEMU) -drive file=./kernel.img,index=0,media=disk,format=raw -serial mon:stdio -vga std -smp 1 -drive file=./fs.img,index=1,media=disk,format=raw

编译JOS

• i386-elf-gcc

  利用Macports来安装i386-elf-gcc

  $ sudo port -v selfupdate
  $ sudo port install i386-elf-gcc

  Macports会帮你下载源码，编译（很是漫长）

• 修改Makefile中的一些内容

  diff --git a/GNUmakefile b/GNUmakefile
  index adc693e..60fe010 100644
  --- a/GNUmakefile
  +++ b/GNUmakefile
  @@ -33,15 +33,15 @@ TOP = .
  
   # try to infer the correct GCCPREFIX
   ifndef GCCPREFIX
  -GCCPREFIX := $(shell if i386-jos-elf-objdump -i 2>&1 | grep '^elf32-i386$$' >/dev/null 2>&1; \
  -       then echo 'i386-jos-elf-'; \
  +GCCPREFIX := $(shell if i386-elf-objdump -i 2>&1 | grep '^elf32-i386$$' >/dev/null 2>&1; \
  +       then echo 'i386-elf-'; \
          elif objdump -i 2>&1 | grep 'elf32-i386' >/dev/null 2>&1; \
          then echo ''; \
          else echo "***" 1>&2; \
          echo "*** Error: Couldn't find an i386-*-elf version of GCC/binutils." 1>&2; \
  -       echo "*** Is the directory with i386-jos-elf-gcc in your PATH?" 1>&2; \
  +       echo "*** Is the directory with i386-elf-gcc in your PATH?" 1>&2; \
          echo "*** If your i386-*-elf toolchain is installed with a command" 1>&2; \
  -       echo "*** prefix other than 'i386-jos-elf-', set your GCCPREFIX" 1>&2; \
  +       echo "*** prefix other than 'i386-elf-', set your GCCPREFIX" 1>&2; \
          echo "*** environment variable to that prefix and run 'make' again." 1>&2; \
          echo "*** To turn off this error, run 'gmake GCCPREFIX= ...'." 1>&2; \
          echo "***" 1>&2; exit 1; fi)

• 修改.deps中一些内容

  删除fsformat的依赖检查

  obj/fs/: fs/fsformat.c

• 修改配置文件中的qemu参数

  QEMU=/usr/local/Cellar/qemu/2.10.0/bin/qemu-system-i386

编译运行JOS