本文基于Android 13的framework层添加系统接口,为应用层提供读写函数、以及执行命令!
添加接口
frameworks/base/core/java/android/app/IDevices.aidl
package android.app;
interface IDevices
{//读取文件String readFile(String path);//写入文件void writeFile(String path,String data);//执行shell命令String shellExec(String cmd);
}
添加系统服务的Manager
frameworks/base/core/java/android/app/DevicesManager.java
package android.app;import android.annotation.SystemService;
import android.content.Context;
import android.os.RemoteException;
import android.util.Slog;@SystemService(Context.DEVICES_SERVICE)
public class DevicesManager {Context mContext;IDevices mService;public DevicesManager(Context context,IDevices service){if(service==null){Slog.e("DevicesManager","Construct service is null");}mContext = context;mService = service;}public String shellExec(String cmd){if(mService != null){try{Slog.e("DevicesManager","shellExec");return mService.shellExec(cmd);}catch(RemoteException e){Slog.e("DevicesManager","RemoteException "+e);}}else{Slog.e("DevicesManager","mService is null");}return "";}public String readFile(String path){if(mService != null){try{Slog.e("DevicesManager","readFile");return mService.readFile(path);}catch(RemoteException e){Slog.e("DevicesManager","RemoteException "+e);}}else{Slog.e("DevicesManager","mService is null");}return "";}public void writeFile(String path,String data){if(mService != null){try{Slog.e("DevicesManager","writeFile");mService.writeFile(path,data);}catch(RemoteException e){Slog.e("DevicesManager","RemoteException "+e);}}else{Slog.e("DevicesManager","mService is null");}}}
添加系统服务,实现aidl文件的接口
frameworks/base/services/core/java/com/android/server/DevicesService.java
package com.android.server; import android.app.IDevices;
import android.content.Context;
import android.os.Build;
import android.util.Log;
import android.util.Slog;import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;import libcore.io.IoUtils;import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.RandomAccessFile;import android.util.Base64;public class DevicesService extends IDevices.Stub {private Context mContext;private String TAG="DevicesService";public DevicesService(Context context){super();mContext = context;Slog.d(TAG,"Construct");}@Overridepublic String shellExec(String cmd){Runtime mRuntime = Runtime.getRuntime();try {//Process中封装了返回的结果和执行错误的结果Slog.d(TAG,"shellExec data:"+cmd);Process mProcess = mRuntime.exec(cmd);BufferedReader mReader = new BufferedReader(new InputStreamReader(mProcess.getInputStream()));StringBuffer mRespBuff = new StringBuffer();char[] buff = new char[1024];int ch = 0;while ((ch = mReader.read(buff)) != -1) {mRespBuff.append(buff, 0, ch);}mReader.close();return mRespBuff.toString();} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();Slog.d(TAG,"shellExec err:"+e.getMessage());}return "";}public static void writeTxtToFile(String strcontent, String filePath) {String strFilePath = filePath;String strContent = strcontent + "\n"; // \r\n 结尾会变成 ^Mtry {File file = new File(strFilePath);makeFilePath(file.getParent(),file.getName());if (!file.exists()) {file.getParentFile().mkdirs();file.createNewFile();}RandomAccessFile raf = new RandomAccessFile(file, "rwd");raf.setLength(0);// 写文件的位置标记,从文件开头开始,后续读取文件内容从该标记开始long writePosition = raf.getFilePointer();raf.seek(writePosition);raf.write(strContent.getBytes());raf.close();//} catch (Exception e) {Log.d("DevicesService","Error on write File:" + e);}}// 生成文件public static File makeFilePath(String filePath, String fileName) {File file = null;makeRootDirectory(filePath);try {file = new File(filePath +"/"+ fileName);if (!file.exists()) {file.createNewFile();}} catch (Exception e) {e.printStackTrace();}return file;}// 生成文件夹public static void makeRootDirectory(String filePath) {File file = null;try {Log.d("FileHelper", "makeRootDirectory "+filePath);file = new File(filePath);if (!file.exists()) {boolean isok= file.mkdir();Log.d("FileHelper", "makeRootDirectory "+filePath+" "+isok);}} catch (Exception e) {Log.d("DevicesService", e+"");}}public static String readFileAll(String path) {File file = new File(path);StringBuilder sb=new StringBuilder();if (file != null && file.exists()) {InputStream inputStream = null;BufferedReader bufferedReader = null;try {inputStream = new FileInputStream(file);bufferedReader = new BufferedReader(new InputStreamReader(inputStream));String outData;while((outData=bufferedReader.readLine())!=null){sb.append(outData+"\n");}} catch (Throwable t) {} finally {try {if (bufferedReader != null) {bufferedReader.close();}} catch (Exception e) {e.printStackTrace();}try {if (inputStream != null) {inputStream.close();}} catch (Exception e) {e.printStackTrace();}}}return sb.toString();}@Overridepublic String readFile(String path){return readFileAll(path);}@Overridepublic void writeFile(String path,String data){writeTxtToFile(data,path);}}
添加服务名称
frameworks/base/core/java/android/content/Context.java
@StringDef(suffix = { "_SERVICE" }, value = {POWER_SERVICE,
/*add_longzhiye*/++ DEVICES_SERVICE,//@hide: POWER_STATS_SERVICE,WINDOW_SERVICE,LAYOUT_INFLATER_SERVICE,ACCOUNT_SERVICE,ACTIVITY_SERVICE,ALARM_SERVICE,public static final String POWER_SERVICE = "power";
++public static final String DEVICES_SERVICE = "devices";
将实现的服务注册到系统中去
frameworks/base/core/java/android/app/SystemServiceRegistry.java
registerService(Context.SEARCH_SERVICE, SearchManager.class,new CachedServiceFetcher<SearchManager>() {@Overridepublic SearchManager createService(ContextImpl ctx) throws ServiceNotFoundException {return new SearchManager(ctx.getOuterContext(),ctx.mMainThread.getHandler());}});
//add longzhiye
registerService(Context.DEVICES_SERVICE,DevicesManager.class,new CachedServiceFetcher<DevicesManager>(){@Overridepublic DevicesManager createService(ContextImpl ctx){IBinder b = ServiceManager.getService(Context.DEVICES_SERVICE);return new DevicesManager(ctx,IDevices.Stub.asInterface(b));} });
//add end
registerService(Context.SENSOR_SERVICE, SensorManager.class,new CachedServiceFetcher<SensorManager>() {@Overridepublic SensorManager createService(ContextImpl ctx) {return new SystemSensorManager(ctx.getOuterContext(),ctx.mMainThread.getHandler().getLooper());}});
将注册的服务设置成开机启动服务
frameworks/base/services/java/com/android/server/SystemServer.java
t.traceBegin("StartTelephonyRegistry");
telephonyRegistry = new TelephonyRegistry(context, new TelephonyRegistry.ConfigurationProvider());
ServiceManager.addService("telephony.registry", telephonyRegistry);
t.traceEnd();
//add longzhiye
t.traceBegin("StartDevicesService");
try{ServiceManager.addService(Context.DEVICES_SERVICE,new DevicesService(context));
} catch(Throwable e){Slog.e("DevicesService","Failed to start DevicesService Service "+e);
}
t.traceEnd();
//add end
让lint检查忽略掉自己的模块
注(Android 11 以后谷歌强制开启lint检查,lint检查不过编译会报错)
frameworks/base/Android.bp
// TODO(b/145644363): move this to under StubLibraries.bp or ApiDocs.bp
metalava_framework_docs_args = "" +"--api-lint-ignore-prefix android.app. " + //add_longzhiye"--api-lint-ignore-prefix android.icu. " +"--api-lint-ignore-prefix java. " +"--api-lint-ignore-prefix junit. " +"--api-lint-ignore-prefix org. " +"--error NoSettingsProvider " +"--error UnhiddenSystemApi " +"--force-convert-to-warning-nullability-annotations +*:-android.*:+android.icu.*:-dalvik.* " +"--hide BroadcastBehavior " +"--hide CallbackInterface " +"--hide DeprecationMismatch " +"--hide HiddenSuperclass " +"--hide HiddenTypeParameter " +"--hide MissingPermission " +"--hide-package android.audio.policy.configuration.V7_0 " +"--hide-package com.android.server " +"--hide RequiresPermission " +"--hide SdkConstant " +"--hide Todo " +"--hide Typo " +"--hide UnavailableSymbol " +"--manifest $(location core/res/AndroidManifest.xml) "
编译源码 更新api接口
make update-api
检查服务是否开启
将编译好的rom 刷入手机,查看sevice list
这里可以看到我们的服务 已经启动了:
服务名称:79 devices: [android.app.IDevices]
longzhiye@longzhiye-laptop:~$ adb shell
coral:/ # service list |grep Device
60 companiondevice: [android.companion.ICompanionDeviceManager]
75 device_identifiers: [android.os.IDeviceIdentifiersPolicyService]
76 device_policy: [android.app.admin.IDevicePolicyManager]
77 device_state: [android.hardware.devicestate.IDeviceStateManager]
78 deviceidle: [android.os.IDeviceIdleController]
79 devices: [android.app.IDevices]
251 virtualdevice: [android.companion.virtual.IVirtualDeviceManager]
coral:/ #
调用测试
应用层项目中引入aidl
// IDevices.aidl
package android.app;// Declare any non-default types here with import statementsinterface IDevices {String shellExec(String cmd);String readFile(String path);void writeFile(String path,String data);
}
调用测试: