Android 应用程序运行shell命令的实现

Android在应用程序中运行shell命令，可以通过如下工具类实现：

package com.example.test;

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

import android.util.Log;

/**
 * 执行shell脚本工具类
 * @author Mountain
 *
 */
public class CommandExecution {

	public static final String TAG = "CommandExecution";
	
	public final static String COMMAND_SU       = "su";
	public final static String COMMAND_SH       = "sh";
	public final static String COMMAND_EXIT     = "exit\n";
	public final static String COMMAND_LINE_END = "\n";

	/**
	 * Command执行结果
	 * @author Mountain
	 *
	 */
	public static class CommandResult {
		public int result = -1;
		public String errorMsg;
		public String successMsg;
	}

	/**
	 * 执行命令—单条
	 * @param command
	 * @param isRoot
	 * @return
	 */
	public static CommandResult execCommand(String command, boolean isRoot) {
		String[] commands = {command};
		return execCommand(commands, isRoot);
	}

	/**
	 * 执行命令-多条
	 * @param commands
	 * @param isRoot
	 * @return
	 */
	public static CommandResult execCommand(String[] commands, boolean isRoot) {
		CommandResult commandResult = new CommandResult();
		if (commands == null || commands.length == 0) return commandResult;
		Process process = null;
		DataOutputStream os = null;
		BufferedReader successResult = null;
		BufferedReader errorResult = null;
		StringBuilder successMsg = null;
		StringBuilder errorMsg = null;
		try {
			process = Runtime.getRuntime().exec(isRoot ? COMMAND_SU : COMMAND_SH);
			os = new DataOutputStream(process.getOutputStream());
			for (String command : commands) {
				if (command != null) {
					os.write(command.getBytes());
					os.writeBytes(COMMAND_LINE_END);
					os.flush();
				}
			}
			os.writeBytes(COMMAND_EXIT);
			os.flush();
			commandResult.result = process.waitFor();
			//获取错误信息
			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);
			commandResult.successMsg = successMsg.toString();
			commandResult.errorMsg = errorMsg.toString();
			Log.i(TAG, commandResult.result + " | " + commandResult.successMsg
					+ " | " + commandResult.errorMsg);
		} catch (IOException e) {
			String errmsg = e.getMessage();
			if (errmsg != null) {
				Log.e(TAG, errmsg);
			} else {
				e.printStackTrace();
			}
		} catch (Exception e) {
			String errmsg = e.getMessage();
			if (errmsg != null) {
				Log.e(TAG, errmsg);
			} else {
				e.printStackTrace();
			}
		} finally {
			try {
				if (os != null) os.close();
				if (successResult != null) successResult.close();
				if (errorResult != null) errorResult.close();
			} catch (IOException e) {
				String errmsg = e.getMessage();
				if (errmsg != null) {
					Log.e(TAG, errmsg);
				} else {
					e.printStackTrace();
				}
			}
			if (process != null) process.destroy();
		}
		return commandResult;
	}
	
}

在其他service中调用该类时，例如实现对eth0的IP地址配置，直接通过下述命令实现：

CommandExecution.execCommand("ifconfig eth0 192.168.1.2",true);

如果需要执行的命令包含变量，可以使用如下方式：

String ip = “192.168.1.2”
String cmd = “ifconfig eth0 ”；
cmd = cmd + ip；
CommandExecution.execCommand(cmd,true);

在Android5.1中，上述命令并不能直接执行成功，会出现如下错误：

java.io.IOException Error running exec(). Command: [su] Working Directory: null Environment: null

修改frameworks/base/cmds/app_process/app_main.cpp文件

int main(int argc, char* const argv[])
 {
+/*
     if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0) < 0) {
         // Older kernels don't understand PR_SET_NO_NEW_PRIVS and return
         // EINVAL. Don't die on such kernels.
             return 12;
         }
     }
+*/