Android Container 系列：详细步骤

2024-02-13 14:06:39

Step I :Compile Android Kernel

Download source code;Kernel's subproject has kernel source code corresponding to the devices here:
```
 https://android.googlesource.com
```
You can find kernel source code path corresponding to your device here
```
 http://source.android.com/source/building-kernels.html
```
Download of this git project is slow,you can use bitbucket or deveo to transfer
checkout branch;Change to the source directory,use
```
 $ git branch -a
```
View all branches,then use
```
 $ git checkout <branch_name>
```
Check codes,here branch_name may have remotes/origin prefix,and there is no need to add -b option,else it will create a new branch
Configuration compiling environment;Clone this repo(you may need transfer):
```
 https://android.googlesource.com/platform/prebuilts/gcc/linux-x86/arm/arm-eabi-4.6
```
set PATH environment variable,add bin directory beneath repo

Compile source code

 $ export ARCH=arm
 $ export SUBARCH=arm
 $ export CROSS_COMPILE=arm-eabi-
 $ make xx_defconfig # (Here you can find) config：http://source.android.com/source/building-kernels.html)
 $ make

Compiled kernel is arch/arm/boot/zImage（Nexus 5 is zImage-dtb）

Flush a new ROM
- Method One:set TARGET_PREBUILT_KERNEL environment variable as compiled kernel,then m make boot.img,using
```
  $ fastboot flash boot boot.img
```
  Flush
- Method Two:copy compiled kernel to out/x/x/x/ directory,named after kernel,then m make boot.img,flush with fastboot

Step II :Compile Android Source Code

Download source code;Here you can find Android versions which devices support:
```
 https://developers.google.com/android/nexus/drivers
```
Download driver;Here has driver corresponding to devices:
```
 https://developers.google.com/android/nexus/drivers
```
Get a script after download and extract,put it in Android directory to execute

Configuration compiling environment

 System：Ubuntu x86_64 EN
 Package：
     build-essential/gcc&g++/lib32stdc++6
     jdk6
     python 2.6.x/2.7.x
     gperf
     libzip/zlib1g&zlib1g-dev/libzzip-dev
     lib32z1
     bison
     flex
     libxml2-utils
     git
     bc
     zip
     squashfs-tools
     libncurses5-dev

Enter Android source code directory;Execute following command to compile source code:

 $ source build/envsetup.sh
 $ lunch # (choose target corresponding to device)
 $ m

Connecting devices;Execute following command to flush a new ROM(you need run as root):
```
 $ adb reboot bootloader
 $ fastboot devices
 $ fastboot flashall -w
```

Step III :Kernel Modification

Conbinder Driver

Enter drivers/staging/android/ directory
Create conbinder.h and conbinder.c
Move the header file of binder.c to conbinder.h,then include "conbinder.h"
Remove static from binder_fops struct's function,then add its declaration in conbinder.h
Add CONBINDER_GET_CURRENT_CONTAINER macro definition in conbinder.h(ioctl operation gets container's ID in which current process is)
Add virtual driver code in conbinder.c
Modify binder_ioctl function in binder.c,add treatment codes of CONBINDER_GET_CURRENT_CONTAINER command
Modify Kconfig,add ANDROID_CONBINDER_IPC option
Modify Makefile,add conbinder.o compilation configuration

Conalarm Driver

Enter drivers/rtc/ directory
Modify alarm-dev.c,add conalarm_fops and conalarm_device data struct,initialize code and customize conalarm_open function
Using macro definition-ANDROID_CONALARM to control relevant conalarm code if compiled
Modify Kconfig,add ANDROID_CONALARM_DEV option
Modify Makefile,add compilation configuration(ccflags) of macro definition ANDROID_CONALARM

Container Driver

Enter drivers/staging/android/ directory
Create container.h and container.c
Add macro definition of ioctl command in container.h
Add driver function,data struct and initialization code of container device in container.c
Modify Kconfig,add ANDROID_CONTAINER option
Modify Makefile,add container.o compilation configuration

Compile Configuration

Modify .config,add following compilation configuration options

 ANDROID_CONBINDER_IPC
 ANDROID_CONALARM_DEV
 ANDROID_CONTAINER
 IKCONFIG
 IKCONFIG_PROC

According to lxc-checkconfig,add compilation configuration options
According toStep II,compile

Step IV :ramdisk modification

init.rc

Remove
```
 mount rootfs rootfs / ro remount
```

Add

 mount tmpfs tmpfs /run
 symlink /system/bin /bin

Add it after PATH environment variable

 :/system/busybox/bin:/system/busybox/sbin:/system/local/bin

Add it after LD_LIBRARY_PATH:
```
 :/system/local/lib
```

Add

 export ANDROID_CT /system/local/var/lib/lxc/android4.x.x

uevent.rc

Add

 /dev/conbinder1         0666    root        root
 ...
 /dev/conbinder9         0666    root        root

Add

 /dev/conalarm           0664   system     radio

Add

 /dev/container          0666    root        root

Step V ：LXC Modification and Compilation

Code modification

Use chroot to replace pivot_root system call

Cross compilinglxc

Download Android NDK
Extract NDK,then execute in it
```
 $ build/tools/make-standalone-toolchain.sh
```
Find tool chain in /tmp directory
Add tool chain directory after PATH environment variable
Download lxc-1.0.0.alpha* source code
Execute in lxc source code
```
 $ autogen.sh
```

Execute

 $ ./configure --host=arm-linux-androideabi --prefix=/system/local CC=arm-linux-androideabi-gcc --disable-capabilities

Execute 'make',ignore relevant lua wrong
Execute
```
 $ sudo make prefix=/system/local install
```
You can find compiled procedure in /system/local

Step VI ：Modify system partitions

Busybox

Put compiled busybox in system directory

LXC

Pack the folders in lxc's installation directory,then extractit in /system/local directory

Cgroups

Create cgroup directory beneath /system/,and Create following directory beneath cgroup
```
 cpuset
 memory
 blkio
 freezer
 device
```

Create script file mount-cgroups.sh beneath /system/local/bin,to mount cgroups and ashmem;command is following:

 for t in `ls /system/cgroup`
 do
     mount -t cgroup -o $t cgroup /system/cgroup/$t
 done

 mkdir /dev/shm
 mount -t tmpfs -o nodev,noexec tmpfs /dev/shm

ServiceManager

Modify filter rule of service name,allow registering modified service

Container configure and root filesystem

Create folder androidx.x.x beneath /system/local/var/lib/lxc to save container system
Create file config and directory rootfs within the folder

config

lxc.utsname = android4.1.2
lxc.tty = 0
lxc.rootfs = /system/local/var/lib/lxc/android4.1.2/rootfs
lxc.cgroup.devices.allow = a

rootfs

Copy all files beneath original system root directory to rootfs directory
Create symbolic Links corresponding to original system root directory

Create directories beneath system root directory,following the principles:(copy means copying directories of host;empty means creating a empty directory；the same below)

 /firmware       copy
 /persist        copy
 /storage        empty
 /config         copy
 /cache          empty
 /acct           empty
 /mnt            empty
 /sys            empty
 /sbin           empty
 /run            empty
 /res            copy
 /proc           empty
 /data           empty
 /root           empty
 /dev            empty
 /system         empty

Create device nodes in rootfs/dev,according to filename,device number,permission and owner of all device files

Create folder and directory beneath system directory,as following rules:

 app                 empty
 bin                 copy
 build.prop          copy
 busybox             copy
 etc                 copy
 fonts               copy
 framework           empty
 lib                 empty
 media               empty
 priv-app            empty
 tts                 copy
 usr                 copy
 vendor              copy
 xbin                copy

Other Script

Create script file mount-bind.sh in android4.x.x directory,Enter the following command：

 mount -o bind /system/app rootfs/system/app
 mount -o bind /system/framework rootfs/system/framework
 mount -o bind /system/lib rootfs/system/lib
 mount -o bind /system/media rootfs/system/media
 mount -o bind /system/priv-app rootfs/system/priv-app

 mount -o bind /dev/conbinder1 rootfs/dev/binder
 mount -o bind /dev/conalarm rootfs/dev/alarm

Create script file share.sh in android4.x.x directory,Enter the following command：
```
 echo "SurfaceFlinger" >>/proc/conbinder/sharedservices
```

init

Forbid creating /dev directory
Forbid mounting tmpfs on /dev directory

init.rc

Forbidden ueventd
Forbidden servicemanager

Step VII :Start Container

Start host
Enter shell using following command as root:
```
 # adb root
 # adb shell
```
Execute following command to mount various folders:
```
 # mount-rw.sh
 # mount-cgroups.sh
```
Enter directory in which container is,and execute following command:
```
 # ./mount-bind.sh
 # ./share.sh  
```
Execute following command to clear log:
```
 # dmesg -c
 # logcat -c
```
Execute following command to start container：
```
 lxc-start -n <container name>
```

码农公寓

Step I :Compile Android Kernel

Step II :Compile Android Source Code

Step III :Kernel Modification

Conbinder Driver

Conalarm Driver

Container Driver

Compile Configuration

Step IV :ramdisk modification

init.rc

uevent.rc

Step V ：LXC Modification and Compilation

Code modification

Cross compilinglxc

Step VI ：Modify system partitions

Busybox

LXC

Cgroups

ServiceManager

Container configure and root filesystem

config

rootfs

Other Script

init

init.rc

Step VII :Start Container

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