在Linux下编译带调试功能的Bochs

在Linux下使用Bochs参考：

http://wangcong.org/articles/bochs.html

http://kinglaw05.blog.163.com/blog/static/59683314200911205510345/

首先，安装libgtk2.0-dev，build-essential库

   1: sudo apt-get install libgtk2.0-dev build-essential

然后下载最新的bochs源码，解压

   1: sudo wget http://bochs.sourceforge.net/svn-snapshot/bochs-20140211.tar.gz

   2: sudo gzip -d bochs-20140211.tar.gz

   3: sudo tar -xvf bochs-20140211.tar

   4: cd bobochs-20140211

配置

将.conf.linux修改成下面模样：

   1: #!/bin/sh

   2: #

   3: # .conf.linux

   4: #

   5:  

   6: #which_config=normal

   7: which_config=plugins

   8:  

   9: CC="gcc"

  10: CXX="c++"

  11: CFLAGS="-Wall -O3 -fomit-frame-pointer -pipe"    # for speed

  12: #CFLAGS="-Wall -g -pipe"                         # for development

  13: CXXFLAGS="$CFLAGS"

  14:  

  15: export CC

  16: export CXX

  17: export CFLAGS

  18: export CXXFLAGS

  19:  

  20:  

  21: case $which_config in

  22:  

  23:   normal)

  24:  

  25:     #######################################################################

  26:     # configuration 1 for release binary RPMs

  27:     # Include a few standard options, speed optimizations, X11 only.

  28:     #######################################################################

  29:     ./configure --enable-sb16 \

  30:                 --enable-ne2000 \

  31:                 --enable-all-optimizations \

  32:                 --enable-cpu-level=6 \

  33:                 --enable-x86-64 \

  34:                 --enable-vmx=2 \

  35:                 --enable-pci \

  36:                 --enable-clgd54xx \

  37:                 --enable-voodoo \

  38:                 --enable-usb \

  39:                 --enable-usb-ohci \

  40:                 --enable-es1370 \

  41:                 --enable-e1000 \

  42:                 --enable-show-ips \

  43:         --enable-debugger \

  44:         --enable-disasm

  45:                 ${CONFIGURE_ARGS}

  46:     ;;

  47:  

  48:   plugins)

  49:     #######################################################################

  50:     # configuration 2 for release binary RPMs

  51:     # Include plugins, every possible gui.

  52:     #######################################################################

  53:     ./configure --enable-sb16 \

  54:                 --enable-ne2000 \

  55:                 --enable-all-optimizations \

  56:                 --enable-cpu-level=6 \

  57:                 --enable-x86-64 \

  58:                 --enable-vmx=2 \

  59:                 --enable-pci \

  60:                 --enable-clgd54xx \

  61:                 --enable-voodoo \

  62:                 --enable-usb \

  63:                 --enable-usb-ohci \

  64:                 --enable-usb-xhci \

  65:                 --enable-es1370 \

  66:                 --enable-e1000 \

  67:                 --enable-plugins \

  68:                 --enable-show-ips \

  69:                 --with-all-libs \

  70:         --enable-debugger \

  71:         --enable-disasm

  72:                 ${CONFIGURE_ARGS}

  73:     ;;

  74:  

  75: esac

修改完后，执行sudo bash .conf.linux脚本进行配置

安装

   1: sudo make

   2: sudo make install

到http://bochs.sourceforge.net/diskimages.html，下载一个已经配置好的img.

   1: sudo wget http://bochs.sourceforge.net/guestos/dlxlinux4.tar.gz

   2: sudo gzip -d dlxlinux4.tar.gz

   3: sudo tar -xvf dlxlinux4.tar

   4: cd dlxlinux4

   5: bochs -q -f bochsrc.txt

就进入了调试状态

   1: daniel@ubuntu:~/linux-3.0/bochs/dlxlinux$ bochs -q -f dlxlinux.bxrc 

   2: ========================================================================

   3:                      Bochs x86 Emulator 2.6.2.svn

   4:               Built from SVN snapshot after release 2.6.2

   5:                   Compiled on Feb 14 2014 at 01:21:35

   6: ========================================================================

   7: 00000000000i[      ] LTDL_LIBRARY_PATH not set. using compile time default '/usr/local/lib/bochs/plugins'

   8: 00000000000i[      ] BXSHARE not set. using compile time default '/usr/local/share/bochs'

   9: 00000000000i[      ] lt_dlhandle is 0xa956340

  10: 00000000000i[PLUGIN] loaded plugin libbx_unmapped.so

  11: 00000000000i[      ] lt_dlhandle is 0xa9569d0

  12: 00000000000i[PLUGIN] loaded plugin libbx_biosdev.so

  13: 00000000000i[      ] lt_dlhandle is 0xa956fb0

  14: 00000000000i[PLUGIN] loaded plugin libbx_speaker.so

  15: 00000000000i[      ] lt_dlhandle is 0xa9577d8

  16: 00000000000i[PLUGIN] loaded plugin libbx_extfpuirq.so

  17: 00000000000i[      ] lt_dlhandle is 0xa957d28

  18: 00000000000i[PLUGIN] loaded plugin libbx_parallel.so

  19: 00000000000i[      ] lt_dlhandle is 0xa959160

  20: 00000000000i[PLUGIN] loaded plugin libbx_serial.so

  21: 00000000000i[      ] lt_dlhandle is 0xa95c400

  22: 00000000000i[PLUGIN] loaded plugin libbx_gameport.so

  23: 00000000000i[      ] lt_dlhandle is 0xa95c9b8

  24: 00000000000i[PLUGIN] loaded plugin libbx_iodebug.so

  25: 00000000000i[      ] reading configuration from dlxlinux.bxrc

  26: 00000000000i[      ] lt_dlhandle is 0xa95cf28

  27: 00000000000i[PLUGIN] loaded plugin libbx_x.so

  28: 00000000000i[      ] installing x module as the Bochs GUI

  29: 00000000000i[      ] using log file bochsout.txt

  30: Next at t=0

  31: (0) [0x0000fffffff0] f000:fff0 (unk. ctxt): jmpf 0xf000:e05b          ; ea5be000f0

  32: <bochs:1> ^C

按下Ctrl+Z可以退出调试程序

关于调试指令，可以参见http://bochs.sourceforge.net/cgi-bin/topper.pl?name=New+Bochs+Documentation&url=http://bochs.sourceforge.net/doc/docbook/user/index.html

dlxlinux内核有一个缺点，就是内核太老了，是1.3版本。

在Bochs img列表中，还有一项

Linux kernel image for x86-64 from Andi Kleen at SuSE, which can be used as a boot floppy. Here is the System.map file for it, which can be useful for debugging.

这里只提供了一个linux内核映像，是bzImage格式，作为floppy挂载可以启动内核，但是提示找不到根文件系统。因此，我们需要自己搞定根文件系统。

不想从头做一个根文件系统，就可以将dlxlinux的拷贝过来用。

怎样将root.img挂载到当前的目录中？

因为root.img里面包含着MBR以及第一个分区，而且第一个分区并不是紧跟在MBR后面，怎么能够知道第一个分区的位置呢？

可以查看MBR中的分区表记录

   1: dlxlinux $ hd root.img -s 446 | head

   2: 000001be  00 01 01 00 83 03 51 31 

11 00 00 00 37 51 00 00

  |......Q1....7Q..|

   3: 000001ce  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

   4: *

   5: 000001fe  55 aa 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |U...............|

   6: 0000020e  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

   7: *

   8: 000025fe  00 00 30 0a 00 00 9b 28  00 00 07 02 00 00 a6 1c  |..0....(........|

   9: 0000260e  00 00 b1 07 00 00 01 00  00 00 00 00 00 00 00 00  |................|

  10: 0000261e  00 00 00 20 00 00 00 20  00 00 18 05 00 00 b4 7a  |... ... .......z|

  11: 0000262e  ff 52 79 17 ff 52 1e 00  14 00 53 ef 00 00 01 00  |.Ry..R....S.....|

红色部分分别代表第一个分区的起始扇区号为0x00000011，扇区个数为0x00005137。

因此， 我们可以用下面命令将root.img挂载起来。

   1: sudo mkdir root

   2: sudo mount -o loop,offset=8704 root.img ./root

其中，8704＝0x11 * 0x200

自己创建一个img，并且将一个文件系统塞进去，并且制作分区表。

http://archive09.linux.com/forums/topic/1519

http://thestarman.pcministry.com/asm/mbr/PartTables.htm

http://aneeska.com/2011/04/07/how-to-create-a-partition-in-an-image-file/

   1: losetup /dev/loop0 root.img

   2: mkfs.ext3 /dev/loop0 

   3: mount /dev/loop0 ./root

   4: # copy files to ./root

   5: umount ./root 

   6: losetup -d /dev/loop0

---

给img扩容

   1: sudo dd if=/dev/zero of=bigroot.img bs=1024 seek=10404 count=5120

   1: fdisk -u bigroot.img -c=dos

打造一个自己的根文件系统，使用指定的Linux内核文件，再加上Grub用于启动。

参考：http://blog.csdn.net/deansrk/article/details/6661293

http://blog.chinaunix.net/uid-26207112-id-3332621.html

但是无法进入

将linux.vdi文件作成linux.img文件，用Bochs进行调试，并且参考System.map中给出的线性地址进行断点设置，发现有执行到/sbin/init初始化任务

   1: do_execve

   2: do_execve_common

   3: open_execve

   4: do_filp_open

   5: path_openat

返回了-1（#define    EPERM         1    /* Operation not permitted */）

即操作不允许错误。

   1: static struct file *path_openat(int dfd, const char *pathname,

   2:         struct nameidata *nd, const struct open_flags *op, int flags)

   3: {

   4:  

   5:     current->total_link_count = 0;

   6:     error = link_path_walk(pathname, nd);

   7:     if (unlikely(error))

   8:         goto out_filp;

   9:  

  10: }