diff --git a/src/main/res/drawable-hdpi/ic_close.png b/src/main/res/drawable-hdpi/ic_close.png
deleted file mode 100644
index ceb1a1ee..00000000
Binary files a/src/main/res/drawable-hdpi/ic_close.png and /dev/null differ
diff --git a/src/main/res/drawable-hdpi/ic_content_add.png b/src/main/res/drawable-hdpi/ic_content_add.png
deleted file mode 100644
index 694179bd..00000000
Binary files a/src/main/res/drawable-hdpi/ic_content_add.png and /dev/null differ
diff --git a/src/main/res/drawable-hdpi/ic_social_share.png b/src/main/res/drawable-hdpi/ic_social_share.png
deleted file mode 100644
index 20ba4806..00000000
Binary files a/src/main/res/drawable-hdpi/ic_social_share.png and /dev/null differ
diff --git a/src/main/res/drawable-hdpi/ic_start_busy.png b/src/main/res/drawable-hdpi/ic_start_busy.png
deleted file mode 100755
index 7b865c00..00000000
Binary files a/src/main/res/drawable-hdpi/ic_start_busy.png and /dev/null differ
diff --git a/src/main/res/drawable-hdpi/ic_start_connected.png b/src/main/res/drawable-hdpi/ic_start_connected.png
deleted file mode 100755
index ef2a562a..00000000
Binary files a/src/main/res/drawable-hdpi/ic_start_connected.png and /dev/null differ
diff --git a/src/main/res/drawable-hdpi/ic_start_idle.png b/src/main/res/drawable-hdpi/ic_start_idle.png
deleted file mode 100755
index 40cafdbe..00000000
Binary files a/src/main/res/drawable-hdpi/ic_start_idle.png and /dev/null differ
diff --git a/src/main/res/drawable-mdpi/ic_close.png b/src/main/res/drawable-mdpi/ic_close.png
deleted file mode 100644
index af7f8288..00000000
Binary files a/src/main/res/drawable-mdpi/ic_close.png and /dev/null differ
diff --git a/src/main/res/drawable-mdpi/ic_content_add.png b/src/main/res/drawable-mdpi/ic_content_add.png
deleted file mode 100644
index 3856041d..00000000
Binary files a/src/main/res/drawable-mdpi/ic_content_add.png and /dev/null differ
diff --git a/src/main/res/drawable-mdpi/ic_social_share.png b/src/main/res/drawable-mdpi/ic_social_share.png
deleted file mode 100644
index f02d360a..00000000
Binary files a/src/main/res/drawable-mdpi/ic_social_share.png and /dev/null differ
diff --git a/src/main/res/drawable-mdpi/ic_start_busy.png b/src/main/res/drawable-mdpi/ic_start_busy.png
deleted file mode 100755
index c620c536..00000000
Binary files a/src/main/res/drawable-mdpi/ic_start_busy.png and /dev/null differ
diff --git a/src/main/res/drawable-mdpi/ic_start_connected.png b/src/main/res/drawable-mdpi/ic_start_connected.png
deleted file mode 100755
index f608d19c..00000000
Binary files a/src/main/res/drawable-mdpi/ic_start_connected.png and /dev/null differ
diff --git a/src/main/res/drawable-mdpi/ic_start_idle.png b/src/main/res/drawable-mdpi/ic_start_idle.png
deleted file mode 100755
index eeebda9a..00000000
Binary files a/src/main/res/drawable-mdpi/ic_start_idle.png and /dev/null differ
diff --git a/src/main/res/drawable-xhdpi/ic_close.png b/src/main/res/drawable-xhdpi/ic_close.png
deleted file mode 100644
index b7c7ffd0..00000000
Binary files a/src/main/res/drawable-xhdpi/ic_close.png and /dev/null differ
diff --git a/src/main/res/drawable-xhdpi/ic_content_add.png b/src/main/res/drawable-xhdpi/ic_content_add.png
deleted file mode 100644
index 67bb598e..00000000
Binary files a/src/main/res/drawable-xhdpi/ic_content_add.png and /dev/null differ
diff --git a/src/main/res/drawable-xhdpi/ic_social_share.png b/src/main/res/drawable-xhdpi/ic_social_share.png
deleted file mode 100644
index 81c80b70..00000000
Binary files a/src/main/res/drawable-xhdpi/ic_social_share.png and /dev/null differ
diff --git a/src/main/res/drawable-xhdpi/ic_start_busy.png b/src/main/res/drawable-xhdpi/ic_start_busy.png
deleted file mode 100755
index 2183c2b2..00000000
Binary files a/src/main/res/drawable-xhdpi/ic_start_busy.png and /dev/null differ
diff --git a/src/main/res/drawable-xhdpi/ic_start_connected.png b/src/main/res/drawable-xhdpi/ic_start_connected.png
deleted file mode 100755
index 49aa370b..00000000
Binary files a/src/main/res/drawable-xhdpi/ic_start_connected.png and /dev/null differ
diff --git a/src/main/res/drawable-xhdpi/ic_start_idle.png b/src/main/res/drawable-xhdpi/ic_start_idle.png
deleted file mode 100755
index 24e37f84..00000000
Binary files a/src/main/res/drawable-xhdpi/ic_start_idle.png and /dev/null differ
diff --git a/src/main/res/drawable-xxhdpi/ic_close.png b/src/main/res/drawable-xxhdpi/ic_close.png
deleted file mode 100644
index 6b717e0d..00000000
Binary files a/src/main/res/drawable-xxhdpi/ic_close.png and /dev/null differ
diff --git a/src/main/res/drawable-xxhdpi/ic_content_add.png b/src/main/res/drawable-xxhdpi/ic_content_add.png
deleted file mode 100644
index 0fdced8f..00000000
Binary files a/src/main/res/drawable-xxhdpi/ic_content_add.png and /dev/null differ
diff --git a/src/main/res/drawable-xxhdpi/ic_social_share.png b/src/main/res/drawable-xxhdpi/ic_social_share.png
deleted file mode 100644
index 784933ad..00000000
Binary files a/src/main/res/drawable-xxhdpi/ic_social_share.png and /dev/null differ
diff --git a/src/main/res/drawable-xxhdpi/ic_start_busy.png b/src/main/res/drawable-xxhdpi/ic_start_busy.png
deleted file mode 100755
index d6c523aa..00000000
Binary files a/src/main/res/drawable-xxhdpi/ic_start_busy.png and /dev/null differ
diff --git a/src/main/res/drawable-xxhdpi/ic_start_connected.png b/src/main/res/drawable-xxhdpi/ic_start_connected.png
deleted file mode 100755
index 9ebdb65b..00000000
Binary files a/src/main/res/drawable-xxhdpi/ic_start_connected.png and /dev/null differ
diff --git a/src/main/res/drawable-xxhdpi/ic_start_idle.png b/src/main/res/drawable-xxhdpi/ic_start_idle.png
deleted file mode 100755
index be36519a..00000000
Binary files a/src/main/res/drawable-xxhdpi/ic_start_idle.png and /dev/null differ
diff --git a/src/main/res/drawable-xxxhdpi/ic_close.png b/src/main/res/drawable-xxxhdpi/ic_close.png
deleted file mode 100644
index 39641921..00000000
Binary files a/src/main/res/drawable-xxxhdpi/ic_close.png and /dev/null differ
diff --git a/src/main/res/drawable-xxxhdpi/ic_content_add.png b/src/main/res/drawable-xxxhdpi/ic_content_add.png
deleted file mode 100644
index d64c22e9..00000000
Binary files a/src/main/res/drawable-xxxhdpi/ic_content_add.png and /dev/null differ
diff --git a/src/main/res/drawable-xxxhdpi/ic_social_share.png b/src/main/res/drawable-xxxhdpi/ic_social_share.png
deleted file mode 100644
index 5a8544ce..00000000
Binary files a/src/main/res/drawable-xxxhdpi/ic_social_share.png and /dev/null differ
diff --git a/src/main/res/drawable-xxxhdpi/ic_start_busy.png b/src/main/res/drawable-xxxhdpi/ic_start_busy.png
deleted file mode 100755
index 3d08a0ef..00000000
Binary files a/src/main/res/drawable-xxxhdpi/ic_start_busy.png and /dev/null differ
diff --git a/src/main/res/drawable-xxxhdpi/ic_start_connected.png b/src/main/res/drawable-xxxhdpi/ic_start_connected.png
deleted file mode 100755
index 496e430a..00000000
Binary files a/src/main/res/drawable-xxxhdpi/ic_start_connected.png and /dev/null differ
diff --git a/src/main/res/drawable-xxxhdpi/ic_start_idle.png b/src/main/res/drawable-xxxhdpi/ic_start_idle.png
deleted file mode 100755
index a4017bc6..00000000
Binary files a/src/main/res/drawable-xxxhdpi/ic_start_idle.png and /dev/null differ
diff --git a/src/main/res/drawable-anydpi-v21/ic_close.xml b/src/main/res/drawable/ic_close.xml
similarity index 100%
rename from src/main/res/drawable-anydpi-v21/ic_close.xml
rename to src/main/res/drawable/ic_close.xml
diff --git a/src/main/res/drawable-anydpi-v21/ic_content_add.xml b/src/main/res/drawable/ic_content_add.xml
similarity index 100%
rename from src/main/res/drawable-anydpi-v21/ic_content_add.xml
rename to src/main/res/drawable/ic_content_add.xml
diff --git a/src/main/res/drawable-anydpi-v21/ic_social_share.xml b/src/main/res/drawable/ic_social_share.xml
similarity index 100%
rename from src/main/res/drawable-anydpi-v21/ic_social_share.xml
rename to src/main/res/drawable/ic_social_share.xml
diff --git a/src/main/res/drawable-anydpi-v21/ic_start_busy.xml b/src/main/res/drawable/ic_start_busy.xml
similarity index 100%
rename from src/main/res/drawable-anydpi-v21/ic_start_busy.xml
rename to src/main/res/drawable/ic_start_busy.xml
diff --git a/src/main/res/drawable-anydpi-v21/ic_start_connected.xml b/src/main/res/drawable/ic_start_connected.xml
similarity index 100%
rename from src/main/res/drawable-anydpi-v21/ic_start_connected.xml
rename to src/main/res/drawable/ic_start_connected.xml
diff --git a/src/main/res/drawable-anydpi-v21/ic_start_idle.xml b/src/main/res/drawable/ic_start_idle.xml
similarity index 100%
rename from src/main/res/drawable-anydpi-v21/ic_start_idle.xml
rename to src/main/res/drawable/ic_start_idle.xml
diff --git a/src/main/scala/com/github/shadowsocks/GuardedProcess.scala b/src/main/scala/com/github/shadowsocks/GuardedProcess.scala
index 8637739a..024c1b79 100644
--- a/src/main/scala/com/github/shadowsocks/GuardedProcess.scala
+++ b/src/main/scala/com/github/shadowsocks/GuardedProcess.scala
@@ -39,67 +39,59 @@
 
 package com.github.shadowsocks
 
-import android.util.Log
-import java.io.IOException
-import java.io.InputStream
-import java.io.OutputStream
-import java.util.concurrent.CountDownLatch
-import java.util.concurrent.atomic.AtomicReference
+import java.io.{IOException, InputStream, OutputStream}
+import java.lang.System.currentTimeMillis
+import java.util.concurrent.Semaphore
 
-import collection.JavaConversions._
+import android.util.Log
+
+import scala.collection.JavaConversions._
 
 /**
   * @author ayanamist@gmail.com
   */
-class GuardedProcess (cmd: Seq[String], onRestartCallback: Runnable = null) extends Process {
-
+class GuardedProcess(cmd: Seq[String]) extends Process {
   private val TAG = classOf[GuardedProcess].getSimpleName
 
-  @volatile private var guardThread: Thread = null
-  @volatile private var isDestroyed: Boolean = false
-  @volatile private var process: Process = null
+  @volatile private var guardThread: Thread = _
+  @volatile private var isDestroyed: Boolean = _
+  @volatile private var process: Process = _
 
-  def start(): GuardedProcess = {
+  def start(onRestartCallback: () => Unit = null): GuardedProcess = {
+    val semaphore = new Semaphore(1)
+    semaphore.acquire
+    @volatile var ioException: IOException = null
 
-    val atomicIoException = new AtomicReference[IOException](null)
-    val countDownLatch = new CountDownLatch(1)
+    guardThread = new Thread(() => {
+      try {
+        var callback: () => Unit = null
+        while (!isDestroyed) {
+          Log.i(TAG, "start process: " + cmd)
+          val startTime = currentTimeMillis
 
-    guardThread = new Thread(new Runnable() {
-      override def run() {
-        try {
-          while (!isDestroyed) {
-            Log.i(TAG, "start process: " + cmd)
-            val startTime = java.lang.System.currentTimeMillis
+          process = new ProcessBuilder(cmd).redirectErrorStream(true).start
 
-            process = new ProcessBuilder(cmd).redirectErrorStream(true).start
-            if (onRestartCallback != null && countDownLatch.getCount <= 0) {
-              onRestartCallback.run()
-            }
+          if (callback == null) callback = onRestartCallback else callback()
 
-            countDownLatch.countDown()
-            process.waitFor
+          semaphore.release
+          process.waitFor
 
-            if (java.lang.System.currentTimeMillis - startTime < 1000) {
-              Log.w(TAG, "process exit too fast, stop guard: " + cmd)
-              return
-            }
+          if (currentTimeMillis - startTime < 1000) {
+            Log.w(TAG, "process exit too fast, stop guard: " + cmd)
+            isDestroyed = true
           }
-        } catch {
-          case ignored: InterruptedException =>
-            Log.i(TAG, "thread interrupt, destroy process: " + cmd)
-            process.destroy()
-          case e: IOException =>
-            atomicIoException.compareAndSet(null, e)
-        } finally {
-          countDownLatch.countDown()
         }
-      }
+      } catch {
+        case ignored: InterruptedException =>
+          Log.i(TAG, "thread interrupt, destroy process: " + cmd)
+          process.destroy()
+        case e: IOException => ioException = e
+      } finally semaphore.release
     }, "GuardThread-" + cmd)
 
     guardThread.start()
-    countDownLatch.await()
+    semaphore.acquire
 
-    val ioException: IOException = atomicIoException.get
     if (ioException != null) {
       throw ioException
     }
@@ -111,32 +103,18 @@ class GuardedProcess (cmd: Seq[String], onRestartCallback: Runnable = null) exte
     isDestroyed = true
     guardThread.interrupt()
     process.destroy()
-    try {
-      guardThread.join()
-    }
-    catch {
+    try guardThread.join() catch {
       case ignored: InterruptedException =>
     }
   }
 
-  def exitValue: Int = {
-    throw new UnsupportedOperationException
-  }
-
-  def getErrorStream: InputStream = {
-    throw new UnsupportedOperationException
-  }
-
-  def getInputStream: InputStream = {
-    throw new UnsupportedOperationException
-  }
-
-  def getOutputStream: OutputStream = {
-    throw new UnsupportedOperationException
-  }
+  def exitValue: Int = throw new UnsupportedOperationException
+  def getErrorStream: InputStream = throw new UnsupportedOperationException
+  def getInputStream: InputStream = throw new UnsupportedOperationException
+  def getOutputStream: OutputStream = throw new UnsupportedOperationException
 
   @throws(classOf[InterruptedException])
-  def waitFor: Int = {
+  def waitFor = {
     guardThread.join()
     0
   }
diff --git a/src/main/scala/com/github/shadowsocks/ServiceBoundContext.scala b/src/main/scala/com/github/shadowsocks/ServiceBoundContext.scala
index 6cba8d7d..74fb80ec 100644
--- a/src/main/scala/com/github/shadowsocks/ServiceBoundContext.scala
+++ b/src/main/scala/com/github/shadowsocks/ServiceBoundContext.scala
@@ -8,11 +8,11 @@ import com.github.shadowsocks.utils.Action
 /**
   * @author Mygod
   */
-trait ServiceBoundContext extends Context { outer =>
+trait ServiceBoundContext extends Context {
   class ShadowsocksServiceConnection extends ServiceConnection {
     override def onServiceConnected(name: ComponentName, service: IBinder) {
+      service.linkToDeath(new ShadowsocksDeathRecipient(ServiceBoundContext.this), 0)
       bgService = IShadowsocksService.Stub.asInterface(service)
-      bgService.asBinder().linkToDeath(new ShadowsocksDeathRecipient(outer), 0)
       registerCallback
       ServiceBoundContext.this.onServiceConnected()
     }
@@ -26,18 +26,18 @@ trait ServiceBoundContext extends Context { outer =>
     }
   }
 
-  def registerCallback = if (bgService != null && callback != null && !callbackRegistered) try {
+  protected def registerCallback = if (bgService != null && callback != null && !callbackRegistered) try {
     bgService.registerCallback(callback)
     callbackRegistered = true
   } catch {
     case ignored: RemoteException => // Nothing
   }
 
-  def unregisterCallback = if (bgService != null && callback != null && callbackRegistered) try {
-    bgService.unregisterCallback(callback)
+  protected def unregisterCallback = {
+    if (bgService != null && callback != null && callbackRegistered) try bgService.unregisterCallback(callback) catch {
+      case ignored: RemoteException =>
+    }
     callbackRegistered = false
-  } catch {
-    case ignored: RemoteException => callbackRegistered = false
   }
 
   def onServiceConnected() = ()
@@ -66,16 +66,12 @@ trait ServiceBoundContext extends Context { outer =>
   }
 
   def deattachService() {
-    if (bgService != null) {
-      if (callback != null) {
-        unregisterCallback
-        callback = null
-      }
-      if (connection != null) {
-        unbindService(connection)
-        connection = null
-      }
-      bgService = null
+    unregisterCallback
+    callback = null
+    if (connection != null) {
+      unbindService(connection)
+      connection = null
     }
+    bgService = null
   }
 }
diff --git a/src/main/scala/com/github/shadowsocks/Shadowsocks.scala b/src/main/scala/com/github/shadowsocks/Shadowsocks.scala
index bcc2b6cc..c854631d 100644
--- a/src/main/scala/com/github/shadowsocks/Shadowsocks.scala
+++ b/src/main/scala/com/github/shadowsocks/Shadowsocks.scala
@@ -275,7 +275,7 @@ class Shadowsocks
     }
   }
 
-  private def crashRecovery() {
+  def crashRecovery() {
     val cmd = new ArrayBuffer[String]()
 
     for (task <- Array("ss-local", "ss-tunnel", "pdnsd", "redsocks", "tun2socks")) {
@@ -318,8 +318,6 @@ class Shadowsocks
     changeSwitch(checked = false)
   }
 
-  def isReady: Boolean = checkText(Key.proxy) && checkText(Key.sitekey) && bgService != null
-
   def prepareStartService() {
     ThrowableFuture {
       if (ShadowsocksApplication.isVpnEnabled) {
@@ -358,18 +356,9 @@ class Shadowsocks
 
     fab = findViewById(R.id.fab).asInstanceOf[FloatingActionButton]
     fabProgressCircle = findViewById(R.id.fabProgressCircle).asInstanceOf[FABProgressCircle]
-    fab.setOnClickListener((v: View) => {
-      serviceStarted = !serviceStarted
-      serviceStarted match {
-        case true =>
-          if (isReady)
-            prepareStartService()
-          else
-            changeSwitch(checked = false)
-        case false =>
-          serviceStop()
-      }
-    })
+    fab.setOnClickListener((v: View) => if (serviceStarted) serviceStop()
+      else if (checkText(Key.proxy) && checkText(Key.sitekey) && bgService != null) prepareStartService()
+      else changeSwitch(checked = false))
     fab.setOnLongClickListener((v: View) => {
       Utils.positionToast(Toast.makeText(this, if (serviceStarted) R.string.stop else R.string.connect,
         Toast.LENGTH_SHORT), fab, getWindow, 0, Utils.dpToPx(this, 8)).show
@@ -377,11 +366,6 @@ class Shadowsocks
     })
     updateTraffic(0, 0, 0, 0)
 
-    bindToService()
-  }
-
-  // Bind to the service
-  def bindToService() {
     handler.post(() => attachService)
   }
 
@@ -488,7 +472,9 @@ class Shadowsocks
     handler.removeCallbacksAndMessages(null)
   }
 
-  def install() {
+  def reset() {
+    crashRecovery()
+
     copyAssets(System.getABI)
 
     val ab = new ArrayBuffer[String]
@@ -498,12 +484,6 @@ class Shadowsocks
     Console.runCommand(ab.toArray)
   }
 
-  def reset() {
-    crashRecovery()
-
-    install()
-  }
-
   def recovery() {
     serviceStop()
     val h = showProgress(R.string.recovering)
diff --git a/src/main/scala/com/github/shadowsocks/ShadowsocksDeathRecipient.scala b/src/main/scala/com/github/shadowsocks/ShadowsocksDeathRecipient.scala
index 97b4b519..5d3ab775 100644
--- a/src/main/scala/com/github/shadowsocks/ShadowsocksDeathRecipient.scala
+++ b/src/main/scala/com/github/shadowsocks/ShadowsocksDeathRecipient.scala
@@ -2,7 +2,6 @@ package com.github.shadowsocks
 
 import android.os.IBinder
 import android.util.Log
-import com.github.shadowsocks.utils.ProcessUtils._
 
 /**
   * @author chentaov5@gmail.com
@@ -14,15 +13,12 @@ class ShadowsocksDeathRecipient(val mContext: ServiceBoundContext)
 
   override def binderDied(): Unit = {
     Log.d(TAG, "[ShadowsocksDeathRecipient] binder died.")
-
     mContext match {
       case ss: Shadowsocks =>
-        inShadowsocks(mContext) {
-          ss.unregisterCallback
-          ss.bindToService()
-        }
+        ss.deattachService
+        ss.crashRecovery
+        ss.attachService
       case _ =>
     }
   }
-
 }
diff --git a/src/main/scala/com/github/shadowsocks/ShadowsocksSettings.scala b/src/main/scala/com/github/shadowsocks/ShadowsocksSettings.scala
index ecdec22d..c99199fe 100644
--- a/src/main/scala/com/github/shadowsocks/ShadowsocksSettings.scala
+++ b/src/main/scala/com/github/shadowsocks/ShadowsocksSettings.scala
@@ -15,7 +15,7 @@ import android.webkit.{WebView, WebViewClient}
 import com.github.shadowsocks.database.Profile
 import com.github.shadowsocks.preferences._
 import com.github.shadowsocks.utils.CloseUtils._
-import com.github.shadowsocks.utils.{Key, Utils}
+import com.github.shadowsocks.utils.Key
 
 object ShadowsocksSettings {
   // Constants
@@ -196,16 +196,10 @@ class ShadowsocksSettings extends PreferenceFragment with OnSharedPreferenceChan
   private var enabled = true
   def setEnabled(enabled: Boolean) {
     this.enabled = enabled
-    findPreference(Key.isNAT).setEnabled(enabled)
-    for (name <- PROXY_PREFS) {
+    for (name <- Key.isNAT #:: PROXY_PREFS.toStream #::: FEATURE_PREFS.toStream) {
       val pref = findPreference(name)
       if (pref != null) pref.setEnabled(enabled)
     }
-    for (name <- FEATURE_PREFS) {
-      val pref = findPreference(name)
-      if (pref != null) pref.setEnabled(enabled &&
-        (name != Key.isProxyApps || Utils.isLollipopOrAbove || !ShadowsocksApplication.isVpnEnabled))
-    }
   }
 
   def update(profile: Profile) {
diff --git a/src/main/scala/com/github/shadowsocks/ShadowsocksVpnService.scala b/src/main/scala/com/github/shadowsocks/ShadowsocksVpnService.scala
index dff53174..8f8d03b3 100644
--- a/src/main/scala/com/github/shadowsocks/ShadowsocksVpnService.scala
+++ b/src/main/scala/com/github/shadowsocks/ShadowsocksVpnService.scala
@@ -44,18 +44,16 @@ import java.lang.Process
 import java.util.Locale
 
 import android.content._
+import android.content.pm.PackageManager.NameNotFoundException
 import android.content.pm.{PackageInfo, PackageManager}
 import android.net.VpnService
 import android.os._
 import android.util.Log
 import android.widget.Toast
-import android.content.pm.PackageManager.NameNotFoundException
-
 import com.github.shadowsocks.aidl.Config
 import com.github.shadowsocks.utils._
 import org.apache.commons.net.util.SubnetUtils
 
-import scala.collection.JavaConversions._
 import scala.collection.mutable.ArrayBuffer
 
 class ShadowsocksVpnService extends VpnService with BaseService {
@@ -434,11 +432,7 @@ class ShadowsocksVpnService extends VpnService with BaseService {
 
     if (BuildConfig.DEBUG) Log.d(TAG, cmd)
 
-    tun2socksProcess = new GuardedProcess(cmd.split(" ").toSeq, new Runnable {
-      override def run(): Unit = {
-        sendFd(fd)
-      }
-    }).start()
+    tun2socksProcess = new GuardedProcess(cmd.split(" ").toSeq).start(() => sendFd(fd))
 
     fd
   }
diff --git a/src/main/scala/com/github/shadowsocks/package.scala b/src/main/scala/com/github/shadowsocks/package.scala
index d0b75ee3..a934b4c8 100644
--- a/src/main/scala/com/github/shadowsocks/package.scala
+++ b/src/main/scala/com/github/shadowsocks/package.scala
@@ -2,17 +2,16 @@ package com.github
 
 import scala.concurrent.ExecutionContext.Implicits.global
 import scala.concurrent.Future
-import scala.util.{Success, Failure, Try}
+import scala.util.{Failure, Try}
 
 /**
   * @author Mygod
   */
 package object shadowsocks {
-
-  val handleFailure: PartialFunction[Try[_], Unit] = {
-    case Success(_) =>
+  private val handleFailure: Try[_] => Unit = {
     case Failure(e) => e.printStackTrace()
+    case _ =>
   }
 
   def ThrowableFuture[T](f: => T) = Future(f) onComplete handleFailure
-}
\ No newline at end of file
+}
diff --git a/src/main/scala/com/github/shadowsocks/utils/CloseUtils.scala b/src/main/scala/com/github/shadowsocks/utils/CloseUtils.scala
index edd85aeb..cb7f9bc1 100644
--- a/src/main/scala/com/github/shadowsocks/utils/CloseUtils.scala
+++ b/src/main/scala/com/github/shadowsocks/utils/CloseUtils.scala
@@ -4,11 +4,14 @@ package com.github.shadowsocks.utils
   * @author Mygod
   */
 object CloseUtils {
+  type Closeable = {
+    def close()
+  }
   type Disconnectable = {
     def disconnect()
   }
 
-  def autoClose[A <: AutoCloseable, B](x: => A)(block: A => B): B = {
+  def autoClose[A <: Closeable, B](x: => A)(block: A => B): B = {
     var a: Option[A] = None
     try {
       a = Some(x)
diff --git a/src/main/scala/com/github/shadowsocks/utils/IOUtils.scala b/src/main/scala/com/github/shadowsocks/utils/IOUtils.scala
deleted file mode 100644
index 0fdf4269..00000000
--- a/src/main/scala/com/github/shadowsocks/utils/IOUtils.scala
+++ /dev/null
@@ -1,33 +0,0 @@
-package com.github.shadowsocks.utils
-
-import android.util.Log
-
-/**
-  * @author chentaov5@gmail.com
-  */
-object IOUtils {
-
-  val TAG = "IOUtils"
-
-  def autoClose[R <: {def close() : Unit}, T](in: R)(fun: => T): T = {
-    try {
-      fun
-    } finally if (in ne null)
-      try {
-        in.close()
-      } catch {
-        case e: Exception => Log.d(TAG, e.getMessage, e)
-      }
-  }
-
-  def inSafe[T](fun: => T): Option[T] = {
-    var res: Option[T] = None
-    try {
-      res = Some(fun)
-    } catch {
-      case e: Exception => Log.d(TAG, e.getMessage, e)
-    }
-    res
-  }
-
-}
diff --git a/src/main/scala/com/github/shadowsocks/utils/ProcessUtils.scala b/src/main/scala/com/github/shadowsocks/utils/ProcessUtils.scala
deleted file mode 100644
index 299ad09c..00000000
--- a/src/main/scala/com/github/shadowsocks/utils/ProcessUtils.scala
+++ /dev/null
@@ -1,44 +0,0 @@
-package com.github.shadowsocks.utils
-
-import java.io.{BufferedReader, FileInputStream, InputStreamReader}
-
-import android.content.Context
-import com.github.shadowsocks.utils.IOUtils._
-
-/**
-  * @author chentaov5@gmail.com
-  */
-object ProcessUtils {
-
-  def getCurrentProcessName: String = {
-    inSafe {
-      val inputStream = new FileInputStream("/proc/self/cmdline")
-      val reader = new BufferedReader(new InputStreamReader(inputStream))
-      autoClose(reader) {
-        val sb = new StringBuilder
-        var c: Int = 0
-        while({c = reader.read(); c > 0})
-          sb.append(c.asInstanceOf[Char])
-        sb.toString()
-      }
-    } match {
-      case Some(name: String) => name
-      case None => ""
-    }
-  }
-
-  def inShadowsocks[A](context: Context)(fun: => A): Unit = {
-    if (context != null && getCurrentProcessName.equals(context.getPackageName)) fun
-  }
-
-
-  def inVpn[A](context: Context)(fun: => A): Unit = {
-    if (context != null && getCurrentProcessName.equals(context.getPackageName + ":vpn")) fun
-  }
-
-
-  def inNat[A](context: Context)(fun: => A): Unit = {
-    if (context != null && getCurrentProcessName.equals(context.getPackageName + ":nat")) fun
-  }
-
-}