Android 8.1RK平台增加自定义脚本，修改文件权限移动开发weixin35649059的博客-

        最近RK3326项目上遇到个问题，OTA升级完重启后需要去/cache/recovery目录下读取一个文件，last_flag,读取过程中报错，提示没有权限，很奇怪，我的明明是系统应用，也加了权限还是报错，所以写个脚本在读取文件之前先设置一下文件的权限，这样就能读取到文件里面的内容。

        首先建立一个脚本 rp_update_file.sh ，内容很简单，就是修改下文件权限如下
 

 #！/system/bin/sh su  chmod 777 /cache/recovery/last_flag

文件放在device/rockchip/rk3326目录下，然后在init.rk3326.rc中添加一个服务，

 #for rp file update service rp_update_file /system/bin/sh /system/etc/rp_update_file.sh     class main     user root     group root     disabled     oneshot     seclabel u:r:shell:s0

再增加一个变量来控制这个服务

 on property:persist.rpfileupdate.enable=1     start rp_update_file on property:persist.rpfileupdate.enable=0     stop rp_update_file

设置一个property，当persist.rpfileupdate.enable=1 时就会去执行这个脚本。

当然还需要给这个脚本添加权限，在system/core/libcutilsfs_config.cpp 目录中增加
 

 diff --git a/core/libcutils/fs_config.cpp b/core/libcutils/fs_config.cpp old mode 100644 new mode 100755 index cc96ff8..9399694 --- a/core/libcutils/fs_config.cpp +++ b/core/libcutils/fs_config.cpp @@ -162,6 +162,8 @@ static const struct fs_path_config android_files[] = {      { 00600, AID_ROOT,      AID_ROOT,      0, "vendor/default.prop" },      { 00444, AID_ROOT,      AID_ROOT,      0, ven_conf_dir + 1 },      { 00444, AID_ROOT,      AID_ROOT,      0, ven_conf_file + 1 }, +        +       { 00755, AID_ROOT,      AID_ROOT,      0, "system/etc/rp_update_file.sh" },        // the following two files are INTENTIONALLY set-uid, but they      // are NOT included on user builds.

OK这样脚本就加好了，然后在android代码中读取文件之前设置一下property，代码如下

 package com.rp.rpreceiver;  import android.app.AlertDialog; import android.content.BroadcastReceiver; import android.content.ComponentName; import android.content.Context; import android.content.Intent; import android.os.Handler; import android.os.Message; import android.os.RecoverySystem; import android.os.storage.StorageManager; import android.provider.Settings; import android.util.Log; import android.view.WindowManager; import android.widget.Toast;  import java.io.File; import java.io.FileReader; import java.io.IOException; import java.lang.reflect.Field; import java.lang.reflect.InvocationTargetException; import java.lang.reflect.Method; import java.security.GeneralSecurityException; import java.util.List;  public class UsbReceiver extends BroadcastReceiver {     private static Boolean isBootComplete = false;     private Handler handler=new Handler(){         @Override         public void handleMessage(Message msg) {             super.handleMessage(msg);         }     };     private static File RECOVERY_DIR = new File("/cache/recovery");     private static File UPDATE_FLAG_FILE = new File(RECOVERY_DIR, "last_flag");     private final String SUCCESS="success";     private final String FAILED="fail";     @Override     public void onReceive(Context context, Intent intent) {         String action = intent.getAction();         Log.i("gyx", "UsbReceiver action=" + action);         Log.i("gyx","isBootComplete="+isBootComplete);         if (action.equals("android.intent.action.BOOT_COMPLETED")) {                        setProperty("persist.rpfileupdate.enable","1");             try {                 Thread.sleep(2000);             } catch (InterruptedException e) {                 e.printStackTrace();             }             int start_ota_upgrade = Settings.System.getInt(context.getContentResolver(), "start_ota_upgrade", 0);             Log.i("gyx","start_ota_upgrade="+start_ota_upgrade);             String command = readFlagCommand();             if(start_ota_upgrade==1){                 Settings.System.putInt(context.getContentResolver(),"start_ota_upgrade",0);                 if(command!=null ){                     if (command.startsWith("success")) {                         Log.i("gyx","update success");                                             } else if (command.startsWith("updating")) {                         Log.i("gyx","update failed");                                             }                 }else {                     Log.i("gyx","command =null update failed");                 }             }             setProperty("persist.rpfileupdate.enable","0");              isBootComplete = true;         }else if (action.equals("android.intent.action.MEDIA_MOUNTED") && isBootComplete) {             String sdCardPath = getSdCardPath(context);             String path = FindFileOnUSB("update.zip");             if (path.equals("")) {                 Log.i("gyx","update.zip not found");             } else {                 Log.i("gyx","update system");                 systemUpdate(context, sdCardPath + "/update.zip");             }          }     }      public static void setProperty(String key, String value) {         try {             Class<?> c = Class.forName("android.os.SystemProperties");             Method set = c.getMethod("set", String.class, String.class);             set.invoke(c, key, value);         } catch (Exception e) {             e.printStackTrace();         }     }   public String getSdCardPath(Context context) {          int TYPE_PUBLIC = 0;          File file = null;          String path = null;          StorageManager mStorageManager = context.getSystemService(StorageManager.class);           Class<?> mVolumeInfo = null;         try {             mVolumeInfo = Class.forName("android.os.storage.VolumeInfo");               Method getVolumes = mStorageManager.getClass().getMethod(                     "getVolumes");               Method volType = mVolumeInfo.getMethod("getType");              Method isMount = mVolumeInfo.getMethod("isMountedReadable");              Method getPath = mVolumeInfo.getMethod("getPath");             Field internalPath = mVolumeInfo.getDeclaredField("internalPath");             List<Object> mListVolumeinfo = (List<Object>) getVolumes                     .invoke(mStorageManager);               Log.d("getSdCardPath", "mListVolumeinfo.size=" + mListVolumeinfo.size());              for (int i = 0; i < mListVolumeinfo.size(); i++) {                  int mType = (Integer) volType.invoke(mListVolumeinfo.get(i));                 Log.d("getSdCardPath", "mType=" + mType);                  if (mType == TYPE_PUBLIC) {                     boolean misMount = (Boolean) isMount.invoke(mListVolumeinfo.get(i));                     Log.d("getSdCardPath", "misMount=" + misMount);                     if (misMount) {                         file = (File) getPath.invoke(mListVolumeinfo.get(i));                         if (file != null) {                             // path = file.getAbsolutePath();                             path = (String) internalPath.get(mListVolumeinfo.get(i));                             Log.d("getSdCardPath", "path=" + path);                             return path;                         }                     }                 }              }          } catch (ClassNotFoundException e) {             // TODO Auto-generated catch block             e.printStackTrace();         } catch (NoSuchMethodException e) {             // TODO Auto-generated catch block             e.printStackTrace();         } catch (IllegalAccessException e) {             // TODO Auto-generated catch block             e.printStackTrace();         } catch (IllegalArgumentException e) {             // TODO Auto-generated catch block             e.printStackTrace();         } catch (InvocationTargetException e) {             // TODO Auto-generated catch block             e.printStackTrace();         } catch (NoSuchFieldException e) {             e.printStackTrace();         }          return "";     }     /**      * 系统升级      */     public void systemUpdate(final Context context, String filepath) {         File updaterFile = new File(filepath);          try {             //升级             RecoverySystem.installPackage(context, updaterFile);          } catch (IOException e) {             e.printStackTrace();         }       }       public static String readFlagCommand() {         if (!UPDATE_FLAG_FILE.exists()) {             return null;         }         Log.d("RKRecoverySystem", "UPDATE_FLAG_FILE is exists");         char[] buf = new char[128];         int readCount = 0;         try {             readCount = new FileReader(UPDATE_FLAG_FILE).read(buf, 0, buf.length);             Log.d("RKRecoverySystem", "readCount = " + readCount + " buf.length = " + buf.length);         } catch (IOException e) {             Log.i("gyx","",e);             Log.e("RKRecoverySystem", "can not read /cache/recovery/last_flag!");         } finally {             UPDATE_FLAG_FILE.delete();         }         StringBuilder sBuilder = new StringBuilder();         int i = 0;         while (i < readCount && buf[i] != 'u0000') {             sBuilder.append(buf[i]);             i++;         }         return sBuilder.toString();     } } 

这样就大功告成了