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- 1. 为何要用到NDK?
概括来说主要分为以下几种情况：
1) 代码的保护，由于apk的java层代码很容易被反编译，而C/C++库反汇难度较大。
2) 在NDK中调用第三方C/C++库，因为大部分的开源库都是用C/C++代码编写的。
3) 便于移植，用C/C++写得库可以方便在其他的嵌入式平台上再次使用。
- 2. 从官网上下载NDK
http://developer.android.com/tools/sdk/ndk/index.html
安装后目录如下：
[dengwei@localhost android-NDK]$ pwd
/home/dengwei/android-NDK
[dengwei@localhost android-NDK]$ ls
build ndk-build platforms RELEASE.TXT toolchains
docs ndk-build.cmd prebuilt samples
documentation.html ndk-gdb README_dengwei sources
GNUmakefile ndk-stack README.TXT tests
为进行用adb模拟环境调试需要安装android SDK
http://developer.android.com/sdk/index.html
安装后目录如下：
[dengwei@localhost android-SDK]$ pwd
/home/dengwei/android-SDK
- 3. 安装完android-NDK android-SDK后，home目录下的.bashrc文件修改红色字体部分
[dengwei@localhost ~]$cat .bashrc
# .bashrc
# Source global definitions
if [ -f /etc/bashrc ]; then
. /etc/bashrc
fi
# User specific aliases and functions
export PATH="/usr/local/toolchain_mipsel/bin:$PATH"
export PATH="/usr/local/toolchain_arm/bin:$PATH"
#export PATH="/home/dengwei/arm-marvell-linux-gnueabi/bin:$PATH"
export PATH="/home/dengwei/android-NDK:$PATH"
export PATH="/home/dengwei/standalone-toolchain/bin:$PATH"
#export PATH="${PATH}:/home/dengwei/android-SDK:"
- 4. 首先需要移植 openssl, curl , libevent ，然后我们才可以移植 transmission.
移植上述三个项目需各自到其官网下载其源码。
正确安装移植上述三个项目后的文件结构图 如下图所示:
[dengwei@localhost ~]$ pwd
/home/dengwei
[dengwei@localhost ~]$ ls porting_*
porting_curl:
bin include lib share
porting_libevent:
bin include lib share
porting_openssl:
bin include lib ssl
- 5. 移植 transmission.
./configure --host=arm-linux --enable-cli --enable-daemon --prefix="/home/dengwei/porting_transmission/install" CXX=arm-linux-androideabi-g++ CC=arm-linux-androideabi-gcc --enable-gtk=no LIBEVENT_CFLAGS="-I /home/dengwei/porting_libevent/include/ -L/home/dengwei/porting_libevent/lib/" LIBCURL_CFLAGS="-I /home/dengwei/porting_curl/include/ -L/home/dengwei/porting_curl/lib/" OPENSSL_CFLAGS="-I /home/dengwei/porting_openssl/include/ -L/home/dengwei/porting_openssl/lib/" LDFLAGS="-L/home/dengwei/porting_libevent/lib/ -levent"
make && make install
有问题参考LDFLAGS
顺利的话，移植完成。
- 6. File信息可以看到：
文件类型已经是ARM的执行文件了
依赖的是 dynamically linked， 也就是说.so 文件
[dengwei@localhost bin]$ file transmissioncli
transmissioncli: ELF 32-bit LSB executable, ARM, version 1 (SYSV), dynamically linked (uses shared libs), not stripped
[dengwei@localhost bin]$ file transmission-daemon
transmission-daemon: ELF 32-bit LSB executable, ARM, version 1 (SYSV), dynamically linked (uses shared libs), not stripped
[dengwei@localhost bin]$ pwd
/home/dengwei/porting_transmission/install/bin
- 7. 以下开始在模拟器搭建，会碰到些只读文件系统的错误，但可以解决。
1) dynamically linked, means we need .so file, so:
PC 上adb 所在目录： /home/dengwei/android-SDK/platform-tools/
./adb push ~/porting_transmission/install /data/
in adb shell,use su and cat to copy file to /system/lib which store .so file
# cat /data/lib/libevent-1.4.so.2 > ./libevent-1.4.so.2
cannot create ./libevent-1.4.so.2: read-only file system
# su
# adb remount
* daemon not running. starting it now on port 5038 *
* daemon started successfully *
remount succeeded
#
PC 上adb 所在目录： /home/dengwei/android-SDK/platform-tools/
./adb push ~/porting_libevent/lib/libevent-1.4.so.2 /data/lib/
./adb push ~/porting_curl/lib/libcurl.so.5 /data/lib/
in adb shell
# pwd
/system/lib
# cat /data/lib/libevent-1.4.so.2 > ./libevent-1.4.so.2
# cat /data/lib/libcurl.so.5 > ./libcurl.so.5
in adb shell
# cat /data/lib/libcurl.so.5 > ./libcurl.so.5
# /data/bin/transmission-daemon
# ps
USER PID PPID VSIZE RSS WCHAN PC NAME
root 530 1 5424 984 ffffffff 40026c94 S /data/bin/transmission-daemon
# /data/bin/transmission-daemon --version
Transmission 2.04 (11151)
2) 最后，我们访问以下web界面以确认是否transmission工作完好。
a) 访问web前，我们需要设置环境变量 TRANSMISSION_HOME (in order to find setting.json and locate torrent resume dir )
TRANSMISSION_WEB_HOME (in order to find web files) environment variables, 否则我们只能得到404错误。
b) 修改环境变量：
export TRANSMISSION_HOME=/data/transmission
export TRANSMISSION_WEB_HOME=/data/transmission/share/transmission/web
#ps
root 556 1 4400 1000 ffffffff 40026c94 S /data/bin/transmission-daemon
root 5724789003480000000040010458 R ps
# kill -9 556
# echo $TRANSMISSION_WEB_HOME
/data/share/transmission/web
# /data/bin/transmission-daemon -u root -v toor -w /sdcard/BT
c) 测试webbrowser访问:http://127.0.0.1:9091 redirect http://127.0.0.1:9091/transmission/web
# /data/bin/transmission-remote --auth=root:toor -a /sdcard/Download/9203e0ebf3e5382dce42ca5add007a32bc0d9bcb.torrent
localhost:9091 responded: "success"
d) 好，现在我们可以看到 transmission web UI
==========================================
- 8. 在真正开发板上：what we need to do :
1) mkdir /data/transmission/
2) mkdir /data/lib/
3) copy porting_transmission/install to board /data/transmission and make them executable by running
chmod 0777 ./* , in directory /data/transmission
4) copy 2 .so file to /data/lib/
5) su
6) #mount -o remount,rw /
7) #copy files in /data/lib/ to /system/lib/
8) #edit /init.rc by adding :
export TRANSMISSION_HOME=/data/transmission
export TRANSMISSION_WEB_HOME=/data/transmission/share/transmission/web
9) also we run 2 export command above
10) start transmission by /data/transmission/bin/transmission-daemon -u root -v toor -w /sdcard/BT
11) /data/bin/transmission-remote --auth=root:toor -a /sdcard/Download/9203e0ebf3e5382dce42ca5add007a32bc0d9bcb.torrent
localhost:9091 responded: "success"
现在，transmission正常工作。
- 9. 附：对应的脚本以省略每次手动操作：
1) start.sh
#!/bin/sh
export TRANSMISSION_HOME=/data/transmission
echo $TRANSMISSION_HOME
export TRANSMISSION_WEB_HOME=/data/transmission/share/transmission/web
echo $TRANSMISSION_WEB_HOME
/data/transmission/bin/transmission-daemon -u root -v toor -w /sdcard/BT -g /data/transmission
2) start_transmission.sh
#!/bin/sh
export TRANSMISSION_HOME=/data/transmission
echo $TRANSMISSION_HOME
export TRANSMISSION_WEB_HOME=/data/transmission/share/transmission/web
echo $TRANSMISSION_WEB_HOME
/data/transmission/bin/transmission-daemon -u root -v toor -w /sdcard/BT -g /data/transmission
ln -s /data/transmission/ /opt
3) start_serverM.sh
#!/bin/sh
mkdir -p /tmp/hdd/volumes/HDD1/BT
mkdir -p /tmp/hdd/volumes/HDD1/torrents
/data/BTControl/serverM > /tmp/hdd/volumes/HDD1/ser_log&
- 10. 参考：
1) Stuck on compiling (cross-compiling using scratchbox).
2) android文件系统结构分析
http://hi.baidu.com/xinyang_wei/item/835b165739f7fa3433e0a95d
http://bbs.gfan.com/android-3707763-1-1.html
4) 在 android上使用 stand-alone toolchains移植 transmission
http://www.cnblogs.com/no7dw/archive/2012/10/08/2715424.html
5) 关于transmission-remote transmission-daemon 用法参考 transmission 的 –h 选项的打印文档。