Android with BusyBox

Android 的shell真是鳥到不行.功能超陽春.

現在教各位安裝busybox到Android的環境中來解決這個問題

1.Download BusyBox -> 這個不用偶教吧 :)
2.
  cd busybox-1.15.1
  make menuconfig

  設定BusyBox為Static link
  BusyBox Settings -> Build Options -> Build BusyBox as a static binary (no shared libs) 

  設定安裝路徑到Android root file system
  BusyBox Settings -> Installation Options -> BusyBox Installation Prefix

  ${HOME}/S3C6410/android_cupcake_smdk6410/opensource_cupcake_0424_opencore203/out/target/product/smdk6410/system/busybox

  Config functions you need...

  make
  make install
3.Go to Android root file system
 
 cd ${HOME}/S3C6410/android_cupcake_smdk6410/opensource_cupcake_0424_opencore203/out/target/product/smdk6410/root

 修改 init.rc 使busybox正常運作

 #    export PATH /sbin:/system/sbin:/system/bin:/system/xbin
export PATH /bin:/system/busybox/sbin:/system/busybox/usr/bin:/system/busybox/usr/sbin:/sbin:/system/sbin:/system/bin:/system/xbin

 使用busybox提供的shell

## Daemon processes to be run by init.
##
#service console /system/bin/sh
service console /system/busybox/bin/sh
    console

4.編輯 /etc/inittab

cd ${HOME}/S3C6410/android_cupcake_smdk6410/opensource_cupcake_0424_opencore203/out/target/product/smdk6410/

產生 system/etc/inittab 內容如下

::sysinit:/etc/init.d/rcS
ttySAC0::askfirst:/system/busybox/bin/sh

5.編輯 /etc/init.d/rcS

mkdir system/etc/init.d

產生 system/etc/init.d/rcS 內容如下

#!/bin/sh
echo "Processing etc/init.d/rc.S"

echo "Starting mdevd"

echo /system/busybox/sbin/mdev > /proc/sys/kernel/hotplug
/system/busybox/sbin/mdev -s

/system/busybox/sbin/ifconfig eth0 192.168.168.209 netmask 255.255.255.0

/system/busybox/usr/sbin/inetd
/system/busybox/usr/sbin/telnetd -l /bin/login

echo "Start Android ..."
 
/init

設定權限為可執行

chmod 755 system/etc/init.d/rcS

5.1 Create device node

sudo mknod root/dev/tty1 c 4 1
sudo mknod root/dev/tty2 c 4 2
sudo mknod root/dev/tty3 c 4 3
sudo mknod root/dev/tty4 c 4 4
sudo mknod root/dev/tty5 c 4 5

sudo mknod root/dev/null c 1 3

sudo mknod root/dev/ttySAC0 c 204 64
cd root/dev
ln -s ttySAC0 console
cd ../..

5.2 Symbolic link

為了讓busybox啟動時找的到 /etc 目錄

cd root
ln -s system/etc etc
cd ..

為了讓busybox啟動時找的到 /bin 目錄

cd root
ln -s system/busybox/bin bin
cd ..

建立linuxrc

cd root
ln -s system/busybox/linuxrc linuxrc
cd ..

6.busybox ftpd

編輯 system/etc/inetd.conf

21 stream tcp nowait root ftpd ftpd -w -v /

產生 system/etc/passwd
         system/etc/group
         system/etc/services
         system/etc/resolv.conf

7.複製system目錄到root file system

8.重新打包Android root file system放到target就可以了

9.kernel param fix

修改 init=/init 為 init=/linuxrc
使得busybox會先被系統執行

10.附記

Android support busybox有點小複雜因為Android本身就有shell.
目前這樣的作法不會覆蓋到Android binary code.是比較好的作法.
system boot會先run busybox,大致流程是

/linuxrc -> /etc/inittab -> /etc/init.d/rcS -> Run ash -> Run /init to start Android -> /init.rc

透過init.rc設定PATH環境變數讓busybox command為優先.