Pileus Git - ~andy/csm213a-hw/blob - syc/src/com/example/sycapp/SerialPort.java

   1 /*
   2  * Copyright 2009 Cedric Priscal
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  * http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 package com.example.sycapp;
  18
  19 import java.io.File;
  20 import java.io.FileDescriptor;
  21 import java.io.FileInputStream;
  22 import java.io.FileOutputStream;
  23 import java.io.IOException;
  24 import java.io.InputStream;
  25 import java.io.OutputStream;
  26
  27 import android.util.Log;
  28
  29 public class SerialPort {
  30
  31         private static final String TAG = "SerialPort";
  32
  33         /*
  34          * Do not remove or rename the field mFd: it is used by native method close();
  35          */
  36         private FileDescriptor mFd;
  37         private FileInputStream mFileInputStream;
  38         private FileOutputStream mFileOutputStream;
  39
  40         public SerialPort(File device, int baudrate, int flags) throws SecurityException, IOException {
  41
  42                 /* Check access permission */
  43                 if (!device.canRead() || !device.canWrite()) {
  44                         try {
  45                                 /* Missing read/write permission, trying to chmod the file */
  46                                 Process su;
  47                                 su = Runtime.getRuntime().exec("/system/bin/su");
  48                                 String cmd = "chmod 666 " + device.getAbsolutePath() + "\n"
  49                                                 + "exit\n";
  50                                 su.getOutputStream().write(cmd.getBytes());
  51                                 if ((su.waitFor() != 0) || !device.canRead()
  52                                                 || !device.canWrite()) {
  53                                         throw new SecurityException();
  54                                 }
  55                         } catch (Exception e) {
  56                                 e.printStackTrace();
  57                                 throw new SecurityException();
  58                         }
  59                 }
  60
  61                 mFd = open(device.getAbsolutePath(), baudrate, flags);
  62                 if (mFd == null) {
  63                         Log.e(TAG, "native open returns null");
  64                         throw new IOException();
  65                 }
  66                 mFileInputStream = new FileInputStream(mFd);
  67                 mFileOutputStream = new FileOutputStream(mFd);
  68         }
  69
  70         // Getters and setters
  71         public InputStream getInputStream() {
  72                 return mFileInputStream;
  73         }
  74
  75         public OutputStream getOutputStream() {
  76                 return mFileOutputStream;
  77         }
  78
  79         // JNI
  80         private native static FileDescriptor open(String path, int baudrate, int flags);
  81         public native void close();
  82         static {
  83                 System.loadLibrary("serial_port");
  84         }
  85 }