Android 自定义shell命令

模拟触摸、按键等操作，直接在命令行输入对应命令即可。命令行如何识别并操作此命令，执行操作的是shell程序，还是java程序？是不是可以添加自定义的命令？

以下在Android13的代码中分析input命令

Android系统中使用了一款叫mksh的shell程序，用于交互式的命令解释器。

mksh

        mksh是一款开源的命令解释器(shell)，aosp中的源码路径是external/mksh，编译后会在/system/bin下生成 "sh"可执行程序，init.rc中配置了开机启动这个二进制程序。当"sh"启动后，终端工具上就会出现我们常知的命令解释器，可以输入shell命令进行操作。

        init.rc中定义了名为"console"的service，service对应的可执行程序是sh这个二进制，这个二进制程序由 exteranl/mksh/Android.bp定义。

service console /system/bin/shclass coreconsoledisableduser shellgroup shell log readprocseclabel u:r:shell:s0

 src/main.c中定义一些指令

static const char *initcoms[] = {Ttypeset, Tdr, initvsn, NULL,Ttypeset, Tdx, "HOME", TPATH, TSHELL, NULL,Ttypeset, "-i10", "COLUMNS", "LINES", "SECONDS", "TMOUT", NULL,Talias,"integer=\\\\builtin typeset -i","local=\\\\builtin typeset",/* not "alias -t --": hash -r needs to work */"hash=\\\\builtin alias -t","type=\\\\builtin whence -v","autoload=\\\\builtin typeset -fu","functions=\\\\builtin typeset -f","history=\\\\builtin fc -l","nameref=\\\\builtin typeset -n","nohup=nohup ","r=\\\\builtin fc -e -","login=\\\\builtin exec login","ll=\\ls -all",NULL,/* this is what AT&T ksh seems to track, with the addition of emacs */Talias, "-tU",Tcat, "cc", "chmod", "cp", "date", "ed", "emacs", "grep", "ls","make", "mv", "pr", "rm", "sed", Tsh, "vi", "who", NULL,NULL 
};

 可在此处添加命令。如：ll=ls -all

cmd命令的入口在frameworks/native/cmds/cmd，在cmd.cpp的cmdMain方法中，根据命令获取对应service

int cmdMain(const std::vector<std::string_view>& argv, TextOutput& outputLog, TextOutput& errorLog, int in, int out, int err, RunMode runMode) {sp<ProcessState> proc = ProcessState::self();proc->startThreadPool();......sp<IServiceManager> sm = defaultServiceManager();if (sm == nullptr) {ALOGW("Unable to get default service manager!");errorLog << "cmd: Unable to get default service manager!" << endl;return 20;}int argc = argv.size();if (argc == 0) {errorLog << "cmd: No service specified; use -l to list all running services. Use -w to start and wait for a service." << endl;return 20;}......const auto cmd = argv[serviceIdx];Vector<String16> args;String16 serviceName = String16(cmd.data(), cmd.size());......sp<IBinder> service;if(waitForService) {service = sm->waitForService(serviceName);} else {service = sm->checkService(serviceName);}......status_t error = IBinder::shellCommand(service, in, out, err, args, cb, result);

首先获取ServiceManage，根据命令获取对应的service，sm->checkService(serviceName);

通过service执行命令IBinder::shellCommand(service, in, out, err, args, cb, result);

因此执行cmd命令的是Java程序，如果执行input命令，需要一个service，系统中InputManagerService处理cmd命令

    @Overridepublic void onShellCommand(FileDescriptor in, FileDescriptor out, FileDescriptor err, String[] args, ShellCallback callback, ResultReceiver resultReceiver) {new InputShellCommand().exec(this, in, out, err, args, callback, resultReceiver);} 

最终InputShellCommand执行命令。

此时命令行还不能识别input命令。需要要添加命令入口

frameworks/base/cmds/input,

#!/system/bin/sh
cmd input "$@"

添加自定义shell命令步骤：

1.创建service，添加到servicemanager中

2.创建命令执行类ShellCommand

3.添加cmd入口脚本