Android通过JNI实现守护进程

/**
 * srvname 进程名
 * sd 之前创建子进程的pid写入的文件路径
 */
int start(int argc, char* srvname, char* sd) {
 pthread_t id;
 int ret;
 struct rlimit r;

 int pid = fork();
 LOGI("fork pid: %d", pid);
 if (pid <0) {
 LOGI("first fork() error pid %d,so exit", pid);
 exit(0);
 } else if (pid != 0) {
 LOGI("first fork(): I'am father pid=%d", getpid());
 //exit(0);
 } else { // 第一个子进程
 LOGI("first fork(): I'am child pid=%d", getpid());
 setsid();
 LOGI("first fork(): setsid=%d", setsid());
 umask(0); //为文件赋予更多的权限，因为继承来的文件可能某些权限被屏蔽

 int pid = fork();
 if (pid == 0) { // 第二个子进程
 // 这里实际上为了防止重复开启线程，应该要有相应处理

 LOGI("I'am child-child pid=%d", getpid());
 chdir("/"); //修改进程工作目录为根目录，chdir(“/”)
 //关闭不需要的从父进程继承过来的文件描述符。
 if (r.rlim_max == RLIM_INFINITY) {
 r.rlim_max = 1024;
 }
 int i;
 for (i = 0; i 

void thread(char* srvname) {
 while(1){
 check_and_restart_service(srvname); // 应该要去判断service状态，这里一直restart 是不足之处
 sleep(4);
 }
}

/**
 * 检测服务，如果不存在服务则启动.
 * 通过am命令启动一个laucher服务,由laucher服务负责进行主服务的检测,laucher服务在检测后自动退出
 */
void check_and_restart_service(char* service) {
 LOGI("当前所在的进程pid=",getpid());
 char cmdline[200];
 sprintf(cmdline, "am startservice --user 0 -n %s", service);
 char tmp[200];
 sprintf(tmp, "cmd=%s", cmdline);
 ExecuteCommandWithPopen(cmdline, tmp, 200);
 LOGI( tmp, LOG);
}  

/**
 * 执行命令
 */
void ExecuteCommandWithPopen(char* command, char* out_result,
 int resultBufferSize) {
 FILE * fp;
 out_result[resultBufferSize - 1] = '\0';
 fp = popen(command, "r");
 if (fp) {
 fgets(out_result, resultBufferSize - 1, fp);
 out_result[resultBufferSize - 1] = '\0';
 pclose(fp);
 } else {
 LOGI("popen null,so exit");
 exit(0);
 }
}

package com.yyh.fork;

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.File;

public class NativeRuntime {

 private static NativeRuntime theInstance = null;

 private NativeRuntime() {

 }
 
 public static NativeRuntime getInstance() {
 if (theInstance == null)
 theInstance = new NativeRuntime();
 return theInstance;
 }

 /**
 * RunExecutable 启动一个可自行的lib*.so文件
 * @date 2016-1-18 下午8:22:28
 * @param pacaageName
 * @param filename
 * @param alias 别名
 * @param args 参数
 * @return
 */
 public String RunExecutable(String pacaageName, String filename, String alias, String args) {
 String path = "/data/data/" + pacaageName;
 String cmd1 = path + "/lib/" + filename;
 String cmd2 = path + "/" + alias;
 String cmd2_a1 = path + "/" + alias + " " + args;
 String cmd3 = "chmod 777 " + cmd2;
 String cmd4 = "dd if=" + cmd1 + " of=" + cmd2;
 StringBuffer sb_result = new StringBuffer();

 if (!new File("/data/data/" + alias).exists()) {
 RunLocalUserCommand(pacaageName, cmd4, sb_result); // 拷贝lib/libtest.so到上一层目录,同时命名为test.
 sb_result.append(";");
 }
 RunLocalUserCommand(pacaageName, cmd3, sb_result); // 改变test的属性,让其变为可执行
 sb_result.append(";");
 RunLocalUserCommand(pacaageName, cmd2_a1, sb_result); // 执行test程序.
 sb_result.append(";");
 return sb_result.toString();
 }

 /**
 * 执行本地用户命令
 * @date 2016-1-18 下午8:23:01
 * @param pacaageName
 * @param command
 * @param sb_out_Result
 * @return
 */
 public boolean RunLocalUserCommand(String pacaageName, String command, StringBuffer sb_out_Result) {
 Process process = null;
 try {
 process = Runtime.getRuntime().exec("sh"); // 获得shell进程
 DataInputStream inputStream = new DataInputStream(process.getInputStream());
 DataOutputStream outputStream = new DataOutputStream(process.getOutputStream());
 outputStream.writeBytes("cd /data/data/" + pacaageName + "\n"); // 保证在command在自己的数据目录里执行,才有权限写文件到当前目录
 outputStream.writeBytes(command + " &\n"); // 让程序在后台运行，前台马上返回
 outputStream.writeBytes("exit\n");
 outputStream.flush();
 process.waitFor();
 byte[] buffer = new byte[inputStream.available()];
 inputStream.read(buffer);
 String s = new String(buffer);
 if (sb_out_Result != null)
 sb_out_Result.append("CMD Result:\n" + s);
 } catch (Exception e) {
 if (sb_out_Result != null)
 sb_out_Result.append("Exception:" + e.getMessage());
 return false;
 }
 return true;
 }

 public native void startActivity(String compname);

 public native String stringFromJNI();

 public native void startService(String srvname, String sdpath);

 public native int findProcess(String packname);

 public native int stopService();

 static {
 try {
 System.loadLibrary("helper"); // 加载so库
 } catch (Exception e) {
 e.printStackTrace();
 }
 }

}

package com.yyh.activity;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.util.Log;

import com.yyh.fork.NativeRuntime;
import com.yyh.utils.FileUtils;
public class PhoneStatReceiver extends BroadcastReceiver {

 private String TAG = "tag";

 @Override
 public void onReceive(Context context, Intent intent) {
 if (Intent.ACTION_BOOT_COMPLETED.equals(intent.getAction())) {
 Log.i(TAG, "手机开机了~~");
 NativeRuntime.getInstance().startService(context.getPackageName() + "/com.yyh.service.HostMonitor", FileUtils.createRootPath());
 } else if (Intent.ACTION_USER_PRESENT.equals(intent.getAction())) {
 }
 }

 
}

package com.yyh.service;

import android.app.Service;
import android.content.Intent;
import android.os.IBinder;
import android.util.Log;

public class HostMonitor extends Service {

 @Override
 public void onCreate() {
 super.onCreate();
 Log.i("daemon_java", "HostMonitor: onCreate! I can not be Killed!");
 }

 @Override
 public int onStartCommand(Intent intent, int flags, int startId) {
 Log.i("daemon_java", "HostMonitor: onStartCommand! I can not be Killed!");
 return super.onStartCommand(intent, flags, startId);
 }

 @Override
 public IBinder onBind(Intent arg0) {
 return null;
 }
}