Kokolo Kokolo - 17 days ago 7
Java Question

java.net.SocketException: socket failed: EACCES (Permission denied) not solved by uses-permission

I just started learning Android and I am trying to successfully send a string from UDP client

I am using PacketSender as the server, but I haven't gotten so far, because my permission is denied.

Here is the code:

public class UDPStringSender extends AppCompatActivity {


Intent intent;
String ipAddress, port;
int portNumber;

boolean shouldLog;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_udp_string_sender);

intent = getIntent();
ipAddress = intent.getStringExtra("ip");
port = intent.getStringExtra("port");
portNumber = Integer.parseInt(port);

Log.d("IP number is", ipAddress);
Log.d("Port number is", port);

shouldLog = true;
}


public void sendString(View view) {
EditText stringField = (EditText)findViewById(R.id.sendableString);
String sendableString = stringField.getText().toString();

DatagramSocket _datagramSocket = null;
try {
_datagramSocket = new DatagramSocket();

InetAddress serverIP = InetAddress.getByName(ipAddress);
if(shouldLog)
Log.d("InetAddress is", serverIP.toString());
DatagramPacket _datagramPacket = new DatagramPacket(sendableString.getBytes(), sendableString.length(), serverIP, portNumber);
if(shouldLog)
Log.d("Packet to be send", _datagramPacket.toString());
_datagramSocket.send(_datagramPacket);

} catch (UnknownHostException e) {
e.printStackTrace();
} catch (SocketException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
} finally {
if(_datagramSocket != null) {
_datagramSocket.close();
if(shouldLog)
Log.d("is datagramSockedClosed", String.valueOf(_datagramSocket.isClosed()));
}
}
}


}

My android manifest:

<?xml version="1.0" encoding="utf-8"?>




<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<activity android:name=".Interface">
<intent-filter>
<action android:name="android.intent.action.MAIN" />

<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name=".UDPStringSender">
</activity>
</application>




As well as my logcat:

11-23 15:58:50.652 31936-31936/co.barakastudio.layouttest W/System.err: java.net.SocketException: socket failed: EACCES (Permission denied)
11-23 15:58:50.652 31936-31936/co.barakastudio.layouttest W/System.err: at libcore.io.IoBridge.socket(IoBridge.java:619)
11-23 15:58:50.652 31936-31936/co.barakastudio.layouttest W/System.err: at java.net.PlainDatagramSocketImpl.create(PlainDatagramSocketImpl.java:93)
11-23 15:58:50.652 31936-31936/co.barakastudio.layouttest W/System.err: at java.net.DatagramSocket.createSocket(DatagramSocket.java:157)
11-23 15:58:50.652 31936-31936/co.barakastudio.layouttest W/System.err: at java.net.DatagramSocket.<init>(DatagramSocket.java:80)
11-23 15:58:50.652 31936-31936/co.barakastudio.layouttest W/System.err: at java.net.DatagramSocket.<init>(DatagramSocket.java:65)
11-23 15:58:50.652 31936-31936/co.barakastudio.layouttest W/System.err: at co.barakastudio.layouttest.UDPStringSender.sendString(UDPStringSender.java:48)
11-23 15:58:50.652 31936-31936/co.barakastudio.layouttest W/System.err: at java.lang.reflect.Method.invoke(Native Method)
11-23 15:58:50.652 31936-31936/co.barakastudio.layouttest W/System.err: at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288)
11-23 15:58:50.652 31936-31936/co.barakastudio.layouttest W/System.err: at android.view.View.performClick(View.java:5697)
11-23 15:58:50.652 31936-31936/co.barakastudio.layouttest W/System.err: at android.widget.TextView.performClick(TextView.java:10826)
11-23 15:58:50.652 31936-31936/co.barakastudio.layouttest W/System.err: at android.view.View$PerformClick.run(View.java:22526)
11-23 15:58:50.652 31936-31936/co.barakastudio.layouttest W/System.err: at android.os.Handler.handleCallback(Handler.java:739)
11-23 15:58:50.652 31936-31936/co.barakastudio.layouttest W/System.err: at android.os.Handler.dispatchMessage(Handler.java:95)
11-23 15:58:50.652 31936-31936/co.barakastudio.layouttest W/System.err: at android.os.Looper.loop(Looper.java:158)
11-23 15:58:50.652 31936-31936/co.barakastudio.layouttest W/System.err: at android.app.ActivityThread.main(ActivityThread.java:7225)
11-23 15:58:50.652 31936-31936/co.barakastudio.layouttest W/System.err: at java.lang.reflect.Method.invoke(Native Method)
11-23 15:58:50.652 31936-31936/co.barakastudio.layouttest W/System.err: at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)
11-23 15:58:50.652 31936-31936/co.barakastudio.layouttest W/System.err: at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)
11-23 15:58:50.652 31936-31936/co.barakastudio.layouttest W/System.err: Caused by: android.system.ErrnoException: socket failed: EACCES (Permission denied)
11-23 15:58:50.652 31936-31936/co.barakastudio.layouttest W/System.err: at libcore.io.Posix.socket(Native Method)
11-23 15:58:50.652 31936-31936/co.barakastudio.layouttest W/System.err: at libcore.io.BlockGuardOs.socket(BlockGuardOs.java:282)
11-23 15:58:50.652 31936-31936/co.barakastudio.layouttest W/System.err: at libcore.io.IoBridge.socket(IoBridge.java:604)
11-23 15:58:50.652 31936-31936/co.barakastudio.layouttest W/System.err: ... 17 more


I really appreciate your time, as it will save tons of mine :)
Cheers,

Answer

Quoting myself:

The <uses-permission> elements should be inside the <manifest> element, but outside the <application> element. In other words, this is fine:

<?xml version="1.0" encoding="utf-8"?>
<manifest
  package="com.commonsware.android.something.something"
  xmlns:android="http://schemas.android.com/apk/res/android">

  <uses-permission android:name="INTERNET"/>
  <uses-permission android:name="ACCESS_NETWORK_STATE"/>

  <application
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/AppTheme">

    <!-- cool stuff goes here -->

  </application>

</manifest>

but this is not:

<?xml version="1.0" encoding="utf-8"?>
<manifest
  package="com.commonsware.android.something.something"
  xmlns:android="http://schemas.android.com/apk/res/android">

  <application
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/AppTheme">

    <uses-permission android:name="INTERNET"/>
    <uses-permission android:name="ACCESS_NETWORK_STATE"/>

    <!-- cool stuff goes here -->

  </application>

</manifest>

While Android Studio will report this if you manually analyze your manifest (Analyze > Inspect Code... from the main menu), it will not automatically show a warning just by having the elements in the wrong spot.