Android: Requesting root access in your app

package com.certusnet.videomonitor;

import java.util.List;
import java.io.IOException;
import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.InputStreamReader;

import android.util.Log;

/**
 * ShellUtils
 * <ul>
 * <strong>Check root</strong>
 * <li>{@link ShellUtils#checkRootPermission()}</li>
 * </ul>
 * <ul>
 * <strong>Execte command</strong>
 * <li>{@link ShellUtils#execCommand(String, boolean)}</li>
 * <li>{@link ShellUtils#execCommand(String, boolean, boolean)}</li>
 * <li>{@link ShellUtils#execCommand(List, boolean)}</li>
 * <li>{@link ShellUtils#execCommand(List, boolean, boolean)}</li>
 * <li>{@link ShellUtils#execCommand(String[], boolean)}</li>
 * <li>{@link ShellUtils#execCommand(String[], boolean, boolean)}</li>
 * </ul>
 * 
 * @author <a href="http://www.trinea.cn" target="_blank">Trinea</a> 2013-5-16
 */
public class ShellUtils {

    public static final String COMMAND_SU = "su";
    public static final String COMMAND_SH = "sh";
    public static final String COMMAND_EXIT = "exit
";
    public static final String COMMAND_LINE_END = "
";

    private ShellUtils() {
        throw new AssertionError();
    }

    /**
     * check whether has root permission
     * 
     * @return
     */
    public static boolean checkRootPermission() {
        return execCommand("echo root", true, false).result == 0;
    }

    /**
     * execute shell command, default return result msg
     * 
     * @param command
     *            command
     * @param isRoot
     *            whether need to run with root
     * @return
     * @see ShellUtils#execCommand(String[], boolean, boolean)
     */
    public static CommandResult execCommand(String command, boolean isRoot) {
        return execCommand(new String[] { command }, isRoot, true);
    }

    /**
     * execute shell commands, default return result msg
     * 
     * @param commands
     *            command list
     * @param isRoot
     *            whether need to run with root
     * @return
     * @see ShellUtils#execCommand(String[], boolean, boolean)
     */
    public static CommandResult execCommand(List<String> commands, boolean isRoot) {
        return execCommand(commands == null ? null : commands.toArray(new String[] {}), isRoot, true);
    }

    /**
     * execute shell commands, default return result msg
     * 
     * @param commands
     *            command array
     * @param isRoot
     *            whether need to run with root
     * @return
     * @see ShellUtils#execCommand(String[], boolean, boolean)
     */
    public static CommandResult execCommand(String[] commands, boolean isRoot) {
        return execCommand(commands, isRoot, true);
    }

    /**
     * execute shell command
     * 
     * @param command
     *            command
     * @param isRoot
     *            whether need to run with root
     * @param isNeedResultMsg
     *            whether need result msg
     * @return
     * @see ShellUtils#execCommand(String[], boolean, boolean)
     */
    public static CommandResult execCommand(String command, boolean isRoot, boolean isNeedResultMsg) {
        return execCommand(new String[] { command }, isRoot, isNeedResultMsg);
    }

    /**
     * execute shell commands
     * 
     * @param commands
     *            command list
     * @param isRoot
     *            whether need to run with root
     * @param isNeedResultMsg
     *            whether need result msg
     * @return
     * @see ShellUtils#execCommand(String[], boolean, boolean)
     */
    public static CommandResult execCommand(List<String> commands, boolean isRoot, boolean isNeedResultMsg) {
        return execCommand(commands == null ? null : commands.toArray(new String[] {}), isRoot, isNeedResultMsg);
    }

    /**
     * execute shell commands
     * 
     * @param commands
     *            command array
     * @param isRoot
     *            whether need to run with root
     * @param isNeedResultMsg
     *            whether need result msg
     * @return <ul>
     *         <li>if isNeedResultMsg is false, {@link CommandResult#successMsg}
     *         is null and {@link CommandResult#errorMsg} is null.</li>
     *         <li>if {@link CommandResult#result} is -1, there maybe some
     *         excepiton.</li>
     *         </ul>
     */
    public static CommandResult execCommand(String[] commands, boolean isRoot, boolean isNeedResultMsg) {
        int result = -1;
        if (commands == null || commands.length == 0) {
            return new CommandResult(result, null, null);
        }

        Process process = null;
        BufferedReader successResult = null;
        BufferedReader errorResult = null;
        StringBuilder successMsg = null;
        StringBuilder errorMsg = null;

        DataOutputStream os = null;
        try {
            process = Runtime.getRuntime().exec(isRoot ? COMMAND_SU : COMMAND_SH);
            os = new DataOutputStream(process.getOutputStream());
            for (String command : commands) {
                if (command == null) {
                    continue;
                }

                
                
                // donnot use os.writeBytes(commmand), avoid chinese charset
                // error
                Log.w("execCommand:", command); 
                os.write(command.getBytes());
                os.writeBytes(COMMAND_LINE_END);
                os.flush();
            }
            os.writeBytes(COMMAND_EXIT);
            os.flush();

            result = process.waitFor();
            // get command result
            if (isNeedResultMsg) {
                successMsg = new StringBuilder();
                errorMsg = new StringBuilder();
                successResult = new BufferedReader(new InputStreamReader(process.getInputStream()));
                errorResult = new BufferedReader(new InputStreamReader(process.getErrorStream()));
                String s;
                while ((s = successResult.readLine()) != null) {
                    successMsg.append(s);
                }
                while ((s = errorResult.readLine()) != null) {
                    errorMsg.append(s);
                }
            }
        } catch (IOException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if (os != null) {
                    os.close();
                }
                if (successResult != null) {
                    successResult.close();
                }
                if (errorResult != null) {
                    errorResult.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }

            if (process != null) {
                process.destroy();
            }
        }
        return new CommandResult(result, successMsg == null ? null : successMsg.toString(), errorMsg == null ? null : errorMsg.toString());
    }

    /**
     * result of command
     * <ul>
     * <li>{@link CommandResult#result} means result of command, 0 means normal,
     * else means error, same to excute in linux shell</li>
     * <li>{@link CommandResult#successMsg} means success message of command
     * result</li>
     * <li>{@link CommandResult#errorMsg} means error message of command result</li>
     * </ul>
     * 
     * @author <a href="http://www.trinea.cn" target="_blank">Trinea</a>
     *         2013-5-16
     */
    public static class CommandResult {

        /** result of command **/
        public int result;
        /** success message of command result **/
        public String successMsg;
        /** error message of command result **/
        public String errorMsg;

        public CommandResult(int result) {
            this.result = result;
        }

        public CommandResult(int result, String successMsg, String errorMsg) {
            this.result = result;
            this.successMsg = successMsg;
            this.errorMsg = errorMsg;
        }
    }
}

调用，root权限启动mt_hls：

String filePath = getFilesDir().getAbsolutePath() + "/mt_hls";
                        CommandResult commandResult = ShellUtils.execCommand(new String[] { "cd /data/data/com.certusnet.videomonitor/files 
", "ulimit -c unlimited 
", "chown root " + filePath + " 
", "chmod 777 " + filePath }, true, false);
                        //CommandResult commandResult = ShellUtils.execCommand(new String[] { "cd /data/data/com.certusnet.videomonitor/files 
", "ulimit -c unlimited 
", "chown root " + filePath + " 
", "chmod 777 " + filePath + " 
",  filePath + " -p any -c -f -d" }, true, false);
                        Log.d("initMonitorProcess", "mawei---" + commandResult.errorMsg + commandResult.result + commandResult.successMsg);
                    

system root权限启动mt_hls：

int ret = system("su -c "/data/data/com.certusnet.videomonitor/files/mt_hls -c -f -p any -d"");                  

注：非root权限的进程，即当前进程无法获取ROOT权限，只能su赋予新独立进程root权限。jni层若果需要root权限，没有办法直接调用。

ioctl 操作驱动文件不需要root权限，但驱动文件必须有可操作权限。

参考：

http://stackoverflow.com/questions/6983156/android-ioctl-root-permissions-and-usage

http://www.stealthcopter.com/blog/2010/01/android-requesting-root-access-in-your-app/