android在apk中擷取root許可權，並執行命令

工程代碼：http://download.csdn.net/detail/victoryckl/4610617

    在apk中，有時候需要root許可權，例如通過apk更新系統庫等system的檔案等，避免升級韌體，或者在apk中需要直接存取某些裝置等。下面是在apk中擷取root許可權的方法，前提是裝置已經root過了。

   關鍵點在於下面這句，通過執行su產生一個具有root許可權的進程：

Process p = Runtime.getRuntime().exec("su");

然後，在向這個進程的寫入要執行的命令，即可達到以root許可權執行命令：

dos = new DataOutputStream(p.getOutputStream());

dos.writeBytes(cmd + "\n");

dos.flush();

或者用下面的方式：

Runtime.getRuntime().exec(new String[]{"/system/bin/su","-c", cmd});

經過測試，以root許可權執行命令，只在真機上測試成功，在模擬器上沒有成功過。

第一次運行時，會出現請求root許可權的介面，選中記住，並允許：

測試程式介面，如果已經root，介面中可以顯示出/system分區對應的裝置節點：

主要檔案：RootCmd.java

package org.ckl.root;import java.io.DataInputStream;import java.io.DataOutputStream;import java.io.IOException;import android.util.Log;public final class RootCmd {private static final String TAG = "RootCmd";private static boolean mHaveRoot = false;// 判斷機器Android是否已經root，即是否擷取root許可權public static boolean haveRoot() {if (!mHaveRoot) {int ret = execRootCmdSilent("echo test"); // 通過執行測試命令來檢測if (ret != -1) {Log.i(TAG, "have root!");mHaveRoot = true;} else {Log.i(TAG, "not root!");}} else {Log.i(TAG, "mHaveRoot = true, have root!");}return mHaveRoot;}// 執行命令並且輸出結果public static String execRootCmd(String cmd) {String result = "";DataOutputStream dos = null;DataInputStream dis = null;try {Process p = Runtime.getRuntime().exec("su");// 經過Root處理的android系統即有su命令dos = new DataOutputStream(p.getOutputStream());dis = new DataInputStream(p.getInputStream());Log.i(TAG, cmd);dos.writeBytes(cmd + "\n");dos.flush();dos.writeBytes("exit\n");dos.flush();String line = null;while ((line = dis.readLine()) != null) {Log.d("result", line);result += line;}p.waitFor();} catch (Exception e) {e.printStackTrace();} finally {if (dos != null) {try {dos.close();} catch (IOException e) {e.printStackTrace();}}if (dis != null) {try {dis.close();} catch (IOException e) {e.printStackTrace();}}}return result;}// 執行命令但不關注結果輸出public static int execRootCmdSilent(String cmd) {int result = -1;DataOutputStream dos = null;try {Process p = Runtime.getRuntime().exec("su");dos = new DataOutputStream(p.getOutputStream());Log.i(TAG, cmd);dos.writeBytes(cmd + "\n");dos.flush();dos.writeBytes("exit\n");dos.flush();p.waitFor();result = p.exitValue();} catch (Exception e) {e.printStackTrace();} finally {if (dos != null) {try {dos.close();} catch (IOException e) {e.printStackTrace();}}}return result;}}

相關檔案：SystemPartition.java，擷取/system分區裝置節點，並支援重新mount /system為可讀寫：

package org.ckl.root;import java.io.DataInputStream;import java.io.File;import java.io.FileInputStream;import java.io.IOException;import android.util.Log;public class SystemPartition {private static final String TAG = "SystemMount";private static String TMP_PATH = "/sdcard/mount.txt";private static String mMountPiont = null;private static boolean mWriteable = false;private SystemPartition() {Log.i(TAG, "new SystemMount()");}private static class SystemPartitionHolder {private static SystemPartition instance = new SystemPartition();}public SystemPartition getInstance() {return SystemPartitionHolder.instance;}public static String getSystemMountPiont() {DataInputStream dis = null;if (mMountPiont == null) { try {RootCmd.execRootCmd("mount > " + TMP_PATH);//Runtime.getRuntime().exec("mount > " + TMP_PATH);dis = new DataInputStream(new FileInputStream(TMP_PATH));String line = null;int index = -1;while ( (line = dis.readLine()) != null ) {index = line.indexOf(" /system ");if (index > 0) {mMountPiont = line.substring(0, index);if (line.indexOf(" rw") > 0) {mWriteable = true;Log.i(TAG, "/system is writeable !");} else {mWriteable = false;Log.i(TAG, "/system is readonly !");}break;}}} catch (Exception e) {e.printStackTrace();} finally {if (dis != null) {try {dis.close();} catch (IOException e1) {e1.printStackTrace();}dis = null;}File f = new File(TMP_PATH);if (f.exists()) {f.delete();}}}if (mMountPiont != null) {Log.i(TAG, "/system mount piont: " + mMountPiont);} else {Log.i(TAG, "get /system mount piont failed !!!");}return mMountPiont;}public static boolean isWriteable() {mMountPiont = null;getSystemMountPiont();return mWriteable;}public static void remountSystem(boolean writeable) {String cmd = null;getSystemMountPiont();if (mMountPiont != null && RootCmd.haveRoot()) {if (writeable) {cmd = "mount -o remount,rw " + mMountPiont + " /system";} else {cmd = "mount -o remount,ro " + mMountPiont + " /system";}RootCmd.execRootCmdSilent(cmd);isWriteable();}}}