Android Open Source - 802.11p-Test-App Capture Thread

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License

The source code is released under:

GNU General Public License

Java Source Code

/*  CaptureThread.java uses java's exec to execute commands as root
    Copyright (C) 2011 Robbie Clemons <robclemons@gmail.com>
/* ww  w.j a v  a  2 s.  c  o m*/
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License along
    with this program; if not, write to the Free Software Foundation, Inc.,
    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. */

package edu.mit.csail.jasongao.sonar;

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

import android.os.Handler;
import android.util.Log;

class CaptureThread extends Thread {
  private static final String TAG = "CaptureThread";

  private Handler muxHandler;

  private final String command;
  private Process process = null;
  private BufferedReader reader = null;
  private DataOutputStream os = null;
  private static final int NUM_ITEMS = 5;

  public CaptureThread(String cmd) throws IOException {
    command = cmd;
    ProcessBuilder pb = new ProcessBuilder().command("su");
    pb.redirectErrorStream(true);
    process = pb.start();
    reader = new BufferedReader(new InputStreamReader(
        process.getInputStream()));
    os = new DataOutputStream(process.getOutputStream());
  }

  public CaptureThread(String cmd, Handler h) throws IOException {
    this(cmd);
    muxHandler = h;
  }

  public void run() {

    class StreamGobbler extends Thread {
      /*
       * "gobblers" seem to be the recommended way to ensure the streams
       * don't cause issues
       */

      public BufferedReader buffReader = null;

      public StreamGobbler(BufferedReader br) {
        buffReader = br;

      }

      public void run() {
        try {
          String line = null;
          String capture = "";
          while ((line = buffReader.readLine()) != null) {
            boolean captureFinished = !line.startsWith("\t0x");
            if (captureFinished) {
              if (muxHandler != null) {
                final String tmpLine = new String(capture);
                muxHandler.obtainMessage(
                    SonarActivity.CAPTURE_RECV, tmpLine)
                    .sendToTarget();
              }
              // capture = line;
              capture = "";
            } else {
              capture += line.substring(9);
            }

          }

        } catch (IOException e) {
          Log.w(TAG, "StreamGobbler couldn't read stream", e);
        } finally {
          try {
            if (buffReader != null) {
              buffReader.close();
              buffReader = null;
            }
          } catch (IOException e) {
            // swallow error
          }
        }
      }
    }

    try {
      os.writeBytes(command + '\n');
      os.flush();
      StreamGobbler stdOutGobbler = new StreamGobbler(reader);
      stdOutGobbler.setDaemon(true);
      stdOutGobbler.start();
      os.writeBytes("exit\n");
      os.flush();
      // The following catastrophe of code seems to be the best way to
      // ensure this thread can be interrupted
      while (!Thread.currentThread().isInterrupted()) {
        try {
          process.exitValue();
          Thread.currentThread().interrupt();
        } catch (IllegalThreadStateException e) {
          // the process hasn't terminated yet so sleep some, then
          // check again
          Thread.sleep(250);// .25 seconds seems reasonable
        }
      }
    } catch (IOException e) {
      Log.e(TAG, "error running commands", e);
    } catch (InterruptedException e) {
      try {
        if (os != null) {
          os.close();// key to killing arpspoof executable and process
          os = null;
        }
        if (reader != null) {
          reader.close();
          reader = null;
        }
      } catch (IOException ex) {
        // swallow error
      } finally {
        if (process != null) {
          process.destroy();
          process = null;
        }
      }
    } finally {
      if (process != null) {
        process.destroy();
        process = null;
      }
    }
  }

}

Java Source Code List

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