adb源码分析

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android adb linux

相关基础信息：

adb	5038	ADB_HOST=1 ADB_HOST_ON_TARGET=1	adb_sysdeps_init适用于linux和windows的版本 adb_trace_init adb_commandline
	adb client	提供HOST端运行的命令
	adb service	HOST端上的一个后台进程
adb daemon	5037 设备开机启动	ADB_HOST=0 ALLOW_ADBD_ROOT=1	adb_qemu_trace_init start_device_log adb_main

Android中adb源码路径：system/core/adb，核心源码列表：

	adb BUILD_EXECUTABLE	adbd BUILD_EXECUTABLE
adb.c \	√	√
adb_auth_client.c \		√
adb_auth_host.c \	√
adb_client.c \	√
backup_service.c \		√
commandline.c \	√
console.c \	√
fdevent.c \	√	√
file_sync_client.c \	√	√
framebuffer_service.c \		√
get_my_path_linux.c \	√
jdwp_service.c \		√
log_service.c \		√
remount_service.c \		√
services.c \	√	√
sockets.c \	√	√
transport.c \	√	√
transport_local.c \	√	√
transport_usb.c \	√	√
usb_linux.c \	√
usb_linux_client.c \		√
usb_vendors.c	√
utils.c \	√	√
$(EXTRA_SRCS) \
$(USB_SRCS) \

Android启动过程adb相关服务及系统属性信息：

1	# create basic filesystem structure
	公私钥认证机制，只允许授权主机使用USB调试接口。保存路径/data/misc/adb/adb_keys
	mkdir /data/misc/adb 02750 system shell
2	# Enable adb security for JB4.2.2
	设置是否启用adb公私钥认证机制，0禁用1启用
	setprop ro.adb.secure 0
3	# adbd is controlled via property triggers in init.<platform>.usb.rc
	service adbd /sbin/adbd
	class core
	socket adbd stream 660 system system
	disabled
	seclabel u:r:adbd:s0
4	# adbd on at boot in emulator
	on property:ro.kernel.qemu=1
	start adbd

以下为linux版adb工具执行过程分析（实用环境可能在机顶盒或车载机上）：

1、命令行执行adb devices，主程序入口，main -> adb_commandline

system/core/ktadb/adb.c::main():Handling commandline()
system/core/ktadb/commandline.c::adb_commandline():getenv ANDROID_SERIAL=(null) ANDROID_ADB_SERVER_PORT=(null) server_port=5038
system/core/ktadb/commandline.c::adb_commandline():adb_commandline() para[0]=devices
system/core/ktadb/commandline.c::adb_commandline():is_server=0 no_daemon=0 is_daemon=0

2、执行函数adb_query()

system/core/ktadb/adb_client.c::adb_query():adb_query: host:devices

a. 验证版本
a.1 验证成功

system/core/ktadb/adb_client.c::_adb_connect():_adb_connect: host:version
30303063 000c
686f73743a76657273696f6e host:version
system/core/ktadb/transport.c::writex():writex: fd=3 len=4: system/core/ktadb/transport.c::writex():writex: fd=3 len=12: system/core/ktadb/transport.c::readx():readx: fd=3 wanted=4
system/core/ktadb/transport.c::readx():readx: fd=3 wanted=4 got=4
4f4b4159 OKAY
system/core/ktadb/adb_client.c::_adb_connect():_adb_connect: return fd 3

system/core/ktadb/transport.c::readx():readx: fd=3 wanted=4
system/core/ktadb/transport.c::readx():readx: fd=3 wanted=4 got=4
30303034 0004

system/core/ktadb/transport.c::readx():readx: fd=3 wanted=4
system/core/ktadb/transport.c::readx():readx: fd=3 wanted=4 got=4
30303166 001f	版本号31

发送4字节+host:version指令，读取OKAY返回结果，读取结果长度及结果内容。

a.2 验证失败

system/core/ktadb/adb_client.c::_adb_connect():_adb_connect: host:version adb_server_name=(null)
system/core/ktadb/adb_client.c::_adb_connect():_adb_connect: socket_loopback_client
system/core/ktadb/adb_client.c::_adb_connect():_adb_connect: return fd -2
system/core/ktadb/adb_client.c::_adb_connect():_adb_connect: error message cannot connect to daemon
system/core/ktadb/adb_client.c::adb_connect():adb_connect: service host:devices, _adb_connect_ret=-2

a.2.launch_server fork()

* daemon not running. starting it now on port 5038 *
system/core/ktadb/adb_client.c::adb_connect():fd == -2 adb_connect:launch_server()
launch_server():fork()
system/core/ktadb/adb.c::main():Handling commandline()
system/core/ktadb/commandline.c::adb_commandline():getenv ANDROID_SERIAL=(null) ANDROID_ADB_SERVER_PORT=(null) server_port=5038
system/core/ktadb/commandline.c::adb_commandline():adb_commandline() para[0]=-P
system/core/ktadb/commandline.c::adb_commandline():adb_commandline() para[1]=5038
system/core/ktadb/commandline.c::adb_commandline():is_server=1 no_daemon=0 is_daemon=1
system/core/ktadb/commandline.c::adb_commandline():adb_commandline::adb_main
system/core/ktadb/adb.c::adb_main():adb.c::adb_main()

a.2.launch_server usb_vendors_init()
   每个设备厂家都会定义一个VID(vender id)来标识自己的usb 设备，ADB service端只会连接已知的VID，这个函数的作用就是初始化一个VID的数组，初始化后这个数组中将包含adb代码中内建的一些厂家的ID以及HOST端的android配置文件中定义的ID。

a.2.launch_server usb_init()
     创建一个线程，线程处理函数device_poll_thread，进入一个循环，每隔1s执行一次find_usb_device和kick_disconnected_devices，find_usb_device搜索所有的usb设备，判断VID是否在上面初始化的列表中，如果是，则将该usb设备注册到一个handle_list中。调用register_usb_transport基于这个fd构造一个atransport类型的对象，再基于这个atransport对象调用register_transport构造一个tmsg类型的对象。
     最后，将这个tmsg对象写到transport_registration_send这个fd，将触发相应的socket监控。kick_disconnected_devices函数判断adb设备是否还正常，不正常的话从handle_list中去掉。

a.2.launch_server local_init(DEFAULT_ADB_LOCAL_TRANSPORT_PORT);

system/core/ktadb/usb_linux.c::device_poll_thread():Created device thread
system/core/ktadb/transport_local.c::local_init():transport: local client init on port 5555

创建一个线程，尝试连接HOST端5555-5585端口，如果连接成功，则返回一个fd，register_socket_transport基于这个fd构造一个atransport类型的对象，再基于这个atransport对象调用register_transport构造一个tmsg类型的对象。最后，将这个tmsg对象写 transport_registration_send这个fd，将触发相应的socket监控。

a.2.launch_server adb_auth_init();

ystem/core/ktadb/adb_auth_host.c::adb_auth_init():adb_auth_init
system/core/ktadb/adb_auth_host.c::get_user_keyfilepath():home '/data'
system/core/ktadb/transport_local.c::client_socket_thread():transport: client_socket_thread() starting
system/core/ktadb/adb_auth_host.c::get_user_key():user key '/data/.android/adbkey'
system/core/ktadb/adb_auth_host.c::read_key():read_key '/data/.android/adbkey'

adbkey.pub文件内容

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 unknown@localhost

a.2.launch_server build_local_name(local_name, sizeof(local_name), server_port)
a.2.launch_server install_listener(local_name, "*smartsocket*", NULL, 0)

system/core/ktadb/usb_linux.c::register_device():[ usb located new device /dev/bus/usb/002/025 (131/3/1) ]
system/core/ktadb/usb_linux.c::register_device():[ usb open /dev/bus/usb/002/025fd = 12]

监听"tcp:5037"，adb client与adb service之间的通讯端口。

a.2.launch_server start_logging()
将stdin重写向到/dev/null，将stdout、stderr重定向/tmp/adb.log，然后输出"adb starting"到stderr。

a.2.launch_server fdevent_loop()
前面通过fdinstall()注册了几个fde，这里就通过一个无限循环epoll相应的fd，有相应的事件则调用fdinstall时注册的处理函数。

a.2.launch_server usb_cleanup()
usb相关的清理工作，对应linux平台的实现目前为空。

* daemon started successfully *

b.获取列表
b.1 设备正常

system/core/ktadb/adb_client.c::_adb_connect():_adb_connect: host:devices
30303063 000c
686f73743a64657669636573 host:devices
system/core/ktadb/transport.c::writex():writex: fd=3 len=4: system/core/ktadb/transport.c::writex():writex: fd=3 len=12: system/core/ktadb/transport.c::readx():readx: fd=3 wanted=4
system/core/ktadb/transport.c::readx():readx: fd=3 wanted=4 got=4
4f4b4159 OKAY
system/core/ktadb/adb_client.c::_adb_connect():_adb_connect: return fd 3
system/core/ktadb/adb_client.c::adb_connect():adb_connect: return fd 3

system/core/ktadb/transport.c::readx():readx: fd=3 wanted=4
system/core/ktadb/transport.c::readx():readx: fd=3 wanted=4 got=4
30303230 0020 结果长度32
system/core/ktadb/transport.c::readx():readx: fd=3 wanted=32
system/core/ktadb/transport.c::readx():readx: fd=3 wanted=32 got=32
31343833453130303531334644303130 1483E100513FD010
List of devices attached
1483E100513FD0100_MTPADB        device

发送4字节+host:devices指令，读取OKAY返回结果，读取结果长度及结果内容。

b.2 设备未授权

system/core/ktadb/adb_client.c::_adb_connect():_adb_connect: host:devices (null)
30303063 000c
686f73743a64657669636573 host:devices
system/core/ktadb/transport.c::writex():writex: fd=3 len=4: system/core/ktadb/transport.c::writex():writex: fd=3 len=12: system/core/ktadb/transport.c::readx():readx: fd=3 wanted=4
system/core/ktadb/transport.c::readx():readx: fd=3 wanted=4 got=4
4f4b4159 OKAY
system/core/ktadb/adb_client.c::_adb_connect():_adb_connect: return fd 3
system/core/ktadb/adb_client.c::adb_connect():adb_connect: return fd 3
system/core/ktadb/transport.c::readx():readx: fd=3 wanted=4
system/core/ktadb/transport.c::readx():readx: fd=3 wanted=4 got=4
30303136 0016
system/core/ktadb/transport.c::readx():readx: fd=3 wanted=22
system/core/ktadb/transport.c::readx():readx: fd=3 wanted=22 got=22
373964373561656309756e617574686f 79d75aec.unautho
List of devices attached
79d75aec        unauthorized

b.3 无设备

system/core/ktadb/adb_client.c::_adb_connect():_adb_connect: host:devices adb_server_name=(null)
system/core/ktadb/adb_client.c::_adb_connect():_adb_connect: socket_loopback_client
30303063 000c
686f73743a64657669636573 host:devices
system/core/ktadb/transport.c::writex():writex: fd=3 len=4: system/core/ktadb/transport.c::writex():writex: fd=3 len=12: system/core/ktadb/transport.c::readx():readx: fd=3 wanted=4
system/core/ktadb/transport.c::readx():readx: fd=3 wanted=4 got=4
4f4b4159 OKAY
system/core/ktadb/adb_client.c::_adb_connect():_adb_connect: return fd 3
system/core/ktadb/adb_client.c::adb_connect():adb_connect: return fd 3
system/core/ktadb/transport.c::readx():readx: fd=3 wanted=4
system/core/ktadb/transport.c::readx():readx: fd=3 wanted=4 got=4
30303030 0000
system/core/ktadb/transport.c::readx():readx: fd=3 wanted=0
system/core/ktadb/transport.c::readx():readx: fd=3 wanted=0 got=0

List of devices attached

主机端
平台	Win 7	Linux
公钥	%USERPROFILE%\.android\adbkey.pub	/data/.android/adbkey.pub
私钥	%USERPROFILE%\.android\adbkey	/data/.android/adbkey

手机	手机弹出主机公钥的指纹(MD5)，询问是否允许
	已验证通过的主机保存在 /data/misc/adb/adb_keys

生成主机公钥指纹:
$ awk "{print $1}" < adbkey.pub | openssl base64 -A -d -a | openssl md5 -c | awk "{print $2}" | tr "[:lower:]" "[:upper:]"
23:B2:47:E1:08:DE:5A:3B:58:5A:A5:A6:FA:98:E0:50

linux平台adb公私钥相关文件夹授权

mkdir /data/.android 0777 system system
export HOME /data

查看已保存主机秘钥信息：

ls -l /data/misc/adb/adb_keys

-rw-r----- system shell
备注：重启手机端adbd会重读/data/misc/adb/adb_keys，或重启手机

在移动设备上打开终端

1、stop adbd;

2、将主机公钥文件放入/mnt/sdcard/文件夹下，新增授权设备(需root权限)，：

cat adbkey.pub >> /data/misc/adb/adb_keys;

3、start adbd.

执行adb kill-server、adb start-server、adb devices查看是否已经连接成功

adb devices

emulator-5554 unauthorized

设置网络调试端口为偶数端口（如：5566），即不会出现此问题，原因：http://blog.csdn.net/span76/article/details/9293937
1) adb 启动就连接5555端口
启动 adb 的时候, adb 通过 "adb fork-server server" 启动 adb deamon
而后deamon 就会去找本地的 5555 端口, 直到 5555+32
ref: jellybean/system/core/adb/transport_local.c#140
为何连接上就叫 emulator, 这是因为 adb 期望自动为用户连接本机的emulator ( 每个emu两个端口, 可以多达16个)
如果你不用service.adb.tcp.port=5566 而用 5565 就是出现 emulator-5564, 因为连接只测试奇数端口

2) 为何连接叫 emulator-5554 而不是 emulator-5555
这是因为缺省emulator的 console 端口是 5554 ( 应该可以用 telnet 连接与 emulator 交互(还没有试验)) , 而adb 的端口是console端口 +1 就是 5555
当使用 adb emu <command> 可能就是把 <command> 发到5554端口

adb log开关
adb.h line 385
fdevent.c line 40

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