From 93084f0ed08a5aaba355179821a833ff6ea46cc5 Mon Sep 17 00:00:00 2001
From: Mygod <mygodstudio@gmail.com>
Date: Sun, 6 Dec 2015 18:49:48 +0800
Subject: [PATCH] Ask for ROOT only when it's needed

---
 src/main/res/values-zh/strings.xml            |  9 ++--
 src/main/res/values/strings.xml               |  9 ++--
 src/main/res/xml/pref_all.xml                 | 10 +++--
 .../com/github/shadowsocks/AppManager.scala   |  4 +-
 .../com/github/shadowsocks/Shadowsocks.scala  | 43 ++++++++-----------
 .../shadowsocks/ShadowsocksApplication.scala  |  5 +--
 .../shadowsocks/ShadowsocksNatService.scala   | 20 ++++-----
 .../shadowsocks/ShadowsocksSettings.scala     | 17 +++-----
 .../shadowsocks/ShadowsocksVpnService.scala   |  6 +--
 .../com/github/shadowsocks/package.scala      | 13 ++++++
 .../preferences/NatSwitchPreference.scala     | 27 ------------
 .../github/shadowsocks/utils/Console.scala    | 14 ++----
 .../com/github/shadowsocks/utils/Utils.scala  | 17 ++++----
 13 files changed, 82 insertions(+), 112 deletions(-)
 create mode 100644 src/main/scala/com/github/shadowsocks/package.scala
 delete mode 100644 src/main/scala/com/github/shadowsocks/preferences/NatSwitchPreference.scala

diff --git a/src/main/res/values-zh/strings.xml b/src/main/res/values-zh/strings.xml
index c3910a87..b79e5088 100755
--- a/src/main/res/values-zh/strings.xml
+++ b/src/main/res/values-zh/strings.xml
@@ -34,6 +34,8 @@
   <string name="auto_connect_summary">随系统启动后台服务</string>
   <string name="forward_success">后台服务已开始运行。</string>
   <string name="service_failed">无法连接远程服务器</string>
+  <string name="nat_no_root">NAT 模式需要 ROOT 权限</string>
+  <string name="switch_to_vpn">切换到 VPN 模式</string>
   <string name="stop">停止服务</string>
   <string name="stopping">正在关闭……</string>
   <string name="vpn_error">后台服务启动失败：%s</string>
@@ -52,14 +54,15 @@
   <string name="about">关于</string>
   <string name="about_title">影梭（shadowsocks）%s</string>
   <string name="flush_dnscache">刷新 DNS 缓存</string>
-  <string name="flush_dnscache_summary_disabled">需要 ROOT 权限</string>
+  <string name="flush_dnscache_summary">只需在 NAT 模式下使用</string>
+  <string name="flush_dnscache_summary_root">只需在 NAT 模式下使用，需要 ROOT 权限</string>
+  <string name="flush_dnscache_no_root">在没有 ROOT 权限的情况下无法刷新 DNS 缓存</string>
   <string name="flushing">刷新中……</string>
   <string name="qrcode">二维码</string>
   <string name="add_profile">添加配置文件</string>
 
   <string name="nat">NAT 模式 (仅限调试)</string>
-  <string name="nat_summary">从 VPN 模式切换为 NAT 模式</string>
-  <string name="nat_summary_no_root">NAT 模式已禁用，需要 ROOT 权限</string>
+  <string name="nat_summary">从 VPN 模式切换为 NAT 模式，需要 ROOT 权限</string>
 
   <string name="udp_dns">UDP 转发</string>
   <string name="udp_dns_summary">由远程服务器转发 UDP 协议的数据包</string>
diff --git a/src/main/res/values/strings.xml b/src/main/res/values/strings.xml
index 7c154a9f..d3d7696f 100644
--- a/src/main/res/values/strings.xml
+++ b/src/main/res/values/strings.xml
@@ -10,8 +10,7 @@
   <string name="profile">Profile</string>
   <string name="profile_summary">Switch to another profile or add new profiles</string>
   <string name="nat">NAT mode (deprecated)</string>
-  <string name="nat_summary">Use NAT mode instead of VPN mode</string>
-  <string name="nat_summary_no_root">NAT mode is disabled without root</string>
+  <string name="nat_summary">Use NAT mode instead of VPN mode. Requires ROOT permission.</string>
   <string name="stat">Network Traffic</string>
   <string name="stat_summary">Sent: \t\t\t\t\t%3$s\t↑\t%1$s/s\nReceived: \t%4$s\t↓\t%2$s/s</string>
   <string name="stat_profiles">\n%1$s↑\t%2$s↓</string>
@@ -61,6 +60,8 @@
   <!-- notification category -->
   <string name="forward_success">Shadowsocks started.</string>
   <string name="service_failed">Failed to connect the remote server</string>
+  <string name="nat_no_root">NAT mode requires ROOT permission</string>
+  <string name="switch_to_vpn">Switch to VPN mode</string>
   <string name="stop">Stop the service</string>
   <string name="stopping">Shutting down…</string>
   <string name="vpn_error">%s</string>
@@ -84,7 +85,9 @@
   <string name="about_title">Shadowsocks %s</string>
   <string name="qrcode">QR Code</string>
   <string name="flush_dnscache">Flush DNS cache</string>
-  <string name="flush_dnscache_summary_disabled">Requires ROOT permission</string>
+  <string name="flush_dnscache_summary">Only useful in NAT mode</string>
+  <string name="flush_dnscache_summary_root">Only useful in NAT mode. Requires ROOT permission.</string>
+  <string name="flush_dnscache_no_root">Flush DNS cache cannot proceed without ROOT permission</string>
   <string name="flushing">Flushing</string>
   <string name="add_profile">Add Profile</string>
   <string name="action_export">Export to Clipboard</string>
diff --git a/src/main/res/xml/pref_all.xml b/src/main/res/xml/pref_all.xml
index 20f23e2a..c5d7a3b5 100644
--- a/src/main/res/xml/pref_all.xml
+++ b/src/main/res/xml/pref_all.xml
@@ -83,12 +83,14 @@
                 android:summary="@string/auto_connect_summary"
                 android:title="@string/auto_connect"/>
 
-        <com.github.shadowsocks.preferences.NatSwitchPreference android:key="isNAT"
-                                                                android:title="@string/nat"
-                                                                android:summary="@string/nat_summary"/>
+        <SwitchPreference android:key="isNAT"
+                          android:title="@string/nat"
+                          android:summary="@string/nat_summary"/>
         <Preference android:key="recovery" android:title="@string/recovery"
             android:summary="@string/recovery_summary"/>
-        <Preference android:key="flush_dnscache" android:title="@string/flush_dnscache"/>
+        <Preference android:key="flush_dnscache"
+                    android:title="@string/flush_dnscache"
+                    android:summary="@string/flush_dnscache_summary_root"/>
         <Preference android:key="about" android:title="@string/about"/>
 
     </PreferenceCategory>
diff --git a/src/main/scala/com/github/shadowsocks/AppManager.scala b/src/main/scala/com/github/shadowsocks/AppManager.scala
index d08e8acb..81c17db3 100644
--- a/src/main/scala/com/github/shadowsocks/AppManager.scala
+++ b/src/main/scala/com/github/shadowsocks/AppManager.scala
@@ -58,8 +58,6 @@ import com.github.shadowsocks.utils.{Key, Utils}
 
 import scala.collection.JavaConversions._
 import scala.collection.mutable
-import scala.concurrent.ExecutionContext.Implicits.global
-import scala.concurrent.Future
 import scala.language.implicitConversions
 
 object AppManager {
@@ -249,7 +247,7 @@ class AppManager extends AppCompatActivity with OnCheckedChangeListener with OnC
   }
 
   def loadAppsAsync() {
-    Future {
+    ThrowableFuture {
       while (!appsLoading) loadApps()
       appsLoading = false
       handler.post(() => {
diff --git a/src/main/scala/com/github/shadowsocks/Shadowsocks.scala b/src/main/scala/com/github/shadowsocks/Shadowsocks.scala
index 37895f30..881c999e 100644
--- a/src/main/scala/com/github/shadowsocks/Shadowsocks.scala
+++ b/src/main/scala/com/github/shadowsocks/Shadowsocks.scala
@@ -65,8 +65,6 @@ import com.github.shadowsocks.utils._
 import com.google.android.gms.ads.{AdRequest, AdSize, AdView}
 
 import scala.collection.mutable.ArrayBuffer
-import scala.concurrent.ExecutionContext.Implicits.global
-import scala.concurrent.Future
 
 object Typefaces {
   def get(c: Context, assetPath: String): Typeface = {
@@ -182,8 +180,13 @@ class Shadowsocks
             handler.postDelayed(() => fabProgressCircle.hide(), 1000)
             fab.setEnabled(true)
             changeSwitch(checked = false)
-            if (m != null) Snackbar.make(findViewById(android.R.id.content),
-              getString(R.string.vpn_error).formatLocal(Locale.ENGLISH, m), Snackbar.LENGTH_LONG).show
+            if (m != null) {
+              val snackbar = Snackbar.make(findViewById(android.R.id.content),
+                getString(R.string.vpn_error).formatLocal(Locale.ENGLISH, m), Snackbar.LENGTH_LONG)
+              if (m == getString(R.string.nat_no_root)) snackbar.setAction(R.string.switch_to_vpn,
+                (_ => preferences.natSwitch.setChecked(false)): View.OnClickListener)
+              snackbar.show
+            }
             setPreferenceEnabled(enabled = true)
           case State.STOPPING =>
             fab.setBackgroundTintList(greyTint)
@@ -317,10 +320,10 @@ class Shadowsocks
       cmd.append("chmod 666 %s%s-vpn.pid".formatLocal(Locale.ENGLISH, Path.BASE, task))
     }
 
-    if (!ShadowsocksApplication.isVpnEnabled) {
-      Console.runRootCommand(cmd.toArray)
-    } else {
+    if (ShadowsocksApplication.isVpnEnabled) {
       Console.runCommand(cmd.toArray)
+    } else {
+      Console.runRootCommand(cmd.toArray)
     }
 
     cmd.clear()
@@ -341,8 +344,7 @@ class Shadowsocks
       cmd.append("rm -f %s%s-vpn.pid".formatLocal(Locale.ENGLISH, Path.BASE, task))
       cmd.append("rm -f %s%s-vpn.conf".formatLocal(Locale.ENGLISH, Path.BASE, task))
     }
-    Console.runCommand(cmd.toArray)
-    if (!ShadowsocksApplication.isVpnEnabled) {
+    if (ShadowsocksApplication.isVpnEnabled) Console.runCommand(cmd.toArray) else {
       Console.runRootCommand(cmd.toArray)
       Console.runRootCommand(Utils.getIptables + " -t nat -F OUTPUT")
     }
@@ -361,7 +363,7 @@ class Shadowsocks
   }
 
   def prepareStartService() {
-    Future {
+    ThrowableFuture {
       if (ShadowsocksApplication.isVpnEnabled) {
         val intent = VpnService.prepare(this)
         if (intent != null) {
@@ -534,18 +536,6 @@ class Shadowsocks
     handler.removeCallbacksAndMessages(null)
   }
 
-  def copyToSystem() {
-    val ab = new ArrayBuffer[String]
-    ab.append("mount -o rw,remount -t yaffs2 /dev/block/mtdblock3 /system")
-    for (executable <- Shadowsocks.EXECUTABLES) {
-      ab.append("cp %s%s /system/bin/".formatLocal(Locale.ENGLISH, Path.BASE, executable))
-      ab.append("chmod 755 /system/bin/" + executable)
-      ab.append("chown root:shell /system/bin/" + executable)
-    }
-    ab.append("mount -o ro,remount -t yaffs2 /dev/block/mtdblock3 /system")
-    Console.runRootCommand(ab.toArray)
-  }
-
   def install() {
     copyAssets(System.getABI)
 
@@ -565,7 +555,7 @@ class Shadowsocks
   def recovery() {
     serviceStop()
     val h = showProgress(R.string.recovering)
-    Future {
+    ThrowableFuture {
       reset()
       h.sendEmptyMessage(0)
     }
@@ -573,8 +563,9 @@ class Shadowsocks
 
   def flushDnsCache() {
     val h = showProgress(R.string.flushing)
-    Future {
-      Utils.toggleAirplaneMode(getBaseContext)
+    ThrowableFuture {
+      if (!Utils.toggleAirplaneMode(getBaseContext)) h.post(() => Snackbar.make(findViewById(android.R.id.content),
+        R.string.flush_dnscache_no_root, Snackbar.LENGTH_LONG).show)
       h.sendEmptyMessage(0)
     }
   }
@@ -595,7 +586,7 @@ class Shadowsocks
   def checkText(key: String): Boolean = {
     val text = ShadowsocksApplication.settings.getString(key, "")
     if (text != null && text.length > 0) return true
-    Snackbar.make(findViewById(android.R.id.content), getString(R.string.proxy_empty), Snackbar.LENGTH_LONG).show
+    Snackbar.make(findViewById(android.R.id.content), R.string.proxy_empty, Snackbar.LENGTH_LONG).show
     false
   }
 
diff --git a/src/main/scala/com/github/shadowsocks/ShadowsocksApplication.scala b/src/main/scala/com/github/shadowsocks/ShadowsocksApplication.scala
index 7bd76fe6..07eb2a60 100644
--- a/src/main/scala/com/github/shadowsocks/ShadowsocksApplication.scala
+++ b/src/main/scala/com/github/shadowsocks/ShadowsocksApplication.scala
@@ -46,7 +46,7 @@ import android.app.Application
 import android.content.pm.PackageManager
 import android.preference.PreferenceManager
 import com.github.shadowsocks.database.{DBHelper, ProfileManager}
-import com.github.shadowsocks.utils.{Console, Key, Utils}
+import com.github.shadowsocks.utils.{Key, Utils}
 import com.google.android.gms.analytics.{GoogleAnalytics, HitBuilders}
 import com.google.android.gms.common.api.ResultCallback
 import com.google.android.gms.tagmanager.{ContainerHolder, TagManager}
@@ -60,8 +60,7 @@ object ShadowsocksApplication {
   lazy val settings = PreferenceManager.getDefaultSharedPreferences(instance)
   lazy val profileManager = new ProfileManager(settings, dbHelper)
 
-  val isRoot = Console.isRoot
-  def isVpnEnabled = !(isRoot && settings.getBoolean(Key.isNAT, !Utils.isLollipopOrAbove))
+  def isVpnEnabled = !settings.getBoolean(Key.isNAT, false)
 
   def getVersionName = try {
     instance.getPackageManager.getPackageInfo(instance.getPackageName, 0).versionName
diff --git a/src/main/scala/com/github/shadowsocks/ShadowsocksNatService.scala b/src/main/scala/com/github/shadowsocks/ShadowsocksNatService.scala
index 865cc586..26374ffc 100644
--- a/src/main/scala/com/github/shadowsocks/ShadowsocksNatService.scala
+++ b/src/main/scala/com/github/shadowsocks/ShadowsocksNatService.scala
@@ -55,8 +55,6 @@ import com.github.shadowsocks.utils._
 
 import scala.collection.JavaConversions._
 import scala.collection.mutable.ArrayBuffer
-import scala.concurrent.ExecutionContext.Implicits.global
-import scala.concurrent.Future
 
 class ShadowsocksNatService extends BaseService {
 
@@ -144,7 +142,7 @@ class ShadowsocksNatService extends BaseService {
       })
       Console.runRootCommand(cmdBuf.toArray)
     } else {
-      Console.runRootCommand(Array("ndc resolver flushdefaultif", "ndc resolver flushif wlan0"))
+      Console.runRootCommand("ndc resolver flushdefaultif", "ndc resolver flushif wlan0")
     }
   }
 
@@ -384,12 +382,17 @@ class ShadowsocksNatService extends BaseService {
         }
       }
     }
-    Console.runRootCommand(init_sb.toArray)
-    Console.runRootCommand(http_sb.toArray)
+    Console.runRootCommand((init_sb ++ http_sb).toArray)
   }
 
   override def startRunner(config: Config) {
 
+    changeState(State.CONNECTING)
+    if (!Console.isRoot) {
+      changeState(State.STOPPED, getString(R.string.nat_no_root))
+      return
+    }
+    
     super.startRunner(config)
 
     // register close receiver
@@ -404,10 +407,7 @@ class ShadowsocksNatService extends BaseService {
 
     ShadowsocksApplication.track(TAG, "start")
 
-    changeState(State.CONNECTING)
-
-    Future {
-
+    ThrowableFuture {
       if (config.proxy == "198.199.101.152") {
         val holder = ShadowsocksApplication.containerHolder
         try {
@@ -465,7 +465,7 @@ class ShadowsocksNatService extends BaseService {
       closeReceiver = null
     }
 
-    notification.destroy()
+    if (notification != null) notification.destroy()
 
     ShadowsocksApplication.track(TAG, "stop")
 
diff --git a/src/main/scala/com/github/shadowsocks/ShadowsocksSettings.scala b/src/main/scala/com/github/shadowsocks/ShadowsocksSettings.scala
index b63c7d81..cc67d043 100644
--- a/src/main/scala/com/github/shadowsocks/ShadowsocksSettings.scala
+++ b/src/main/scala/com/github/shadowsocks/ShadowsocksSettings.scala
@@ -14,6 +14,7 @@ import com.github.shadowsocks.utils.Key
 // TODO: Move related logic here
 class ShadowsocksSettings extends PreferenceFragment with OnSharedPreferenceChangeListener {
   private lazy val activity = getActivity.asInstanceOf[Shadowsocks]
+  lazy val natSwitch = findPreference(Key.isNAT).asInstanceOf[SwitchPreference]
 
   private var isProxyApps: SwitchPreference = _
 
@@ -35,10 +36,8 @@ class ShadowsocksSettings extends PreferenceFragment with OnSharedPreferenceChan
     })
 
     val flush = findPreference("flush_dnscache")
-    if (Build.VERSION.SDK_INT >= 17 && !ShadowsocksApplication.isRoot) {
-      flush.setEnabled(false)
-      flush.setSummary(R.string.flush_dnscache_summary_disabled)
-    } else flush.setOnPreferenceClickListener((preference: Preference) => {
+    if (Build.VERSION.SDK_INT < 17) flush.setSummary(R.string.flush_dnscache_summary)
+    flush.setOnPreferenceClickListener(_ => {
       ShadowsocksApplication.track(Shadowsocks.TAG, "flush_dnscache")
       activity.flushDnsCache()
       true
@@ -73,12 +72,10 @@ class ShadowsocksSettings extends PreferenceFragment with OnSharedPreferenceChan
   }
 
   def onSharedPreferenceChanged(sharedPreferences: SharedPreferences, key: String) = key match {
-    case Key.isNAT => if (ShadowsocksApplication.isRoot && activity != null) {
-      activity.handler.post(() => {
-        activity.deattachService
-        activity.attachService
-      })
-    }
+    case Key.isNAT => activity.handler.post(() => {
+      activity.deattachService
+      activity.attachService
+    })
     case _ =>
   }
 }
diff --git a/src/main/scala/com/github/shadowsocks/ShadowsocksVpnService.scala b/src/main/scala/com/github/shadowsocks/ShadowsocksVpnService.scala
index 3140baaf..ac832422 100644
--- a/src/main/scala/com/github/shadowsocks/ShadowsocksVpnService.scala
+++ b/src/main/scala/com/github/shadowsocks/ShadowsocksVpnService.scala
@@ -55,8 +55,6 @@ import org.apache.commons.net.util.SubnetUtils
 
 import scala.collection.JavaConversions._
 import scala.collection.mutable.ArrayBuffer
-import scala.concurrent.ExecutionContext.Implicits.global
-import scala.concurrent.Future
 
 class ShadowsocksVpnService extends VpnService with BaseService {
   val TAG = "ShadowsocksVpnService"
@@ -122,7 +120,7 @@ class ShadowsocksVpnService extends VpnService with BaseService {
       vpnThread = null
     }
 
-    notification.destroy()
+    if (notification != null) notification.destroy()
 
     // channge the state
     changeState(State.STOPPING)
@@ -213,7 +211,7 @@ class ShadowsocksVpnService extends VpnService with BaseService {
 
     changeState(State.CONNECTING)
 
-    Future {
+    ThrowableFuture {
       if (config.proxy == "198.199.101.152") {
         val holder = ShadowsocksApplication.containerHolder
         try {
diff --git a/src/main/scala/com/github/shadowsocks/package.scala b/src/main/scala/com/github/shadowsocks/package.scala
new file mode 100644
index 00000000..a6db148d
--- /dev/null
+++ b/src/main/scala/com/github/shadowsocks/package.scala
@@ -0,0 +1,13 @@
+package com.github
+
+import scala.concurrent.ExecutionContext.Implicits.global
+import scala.concurrent.Future
+
+/**
+  * @author Mygod
+  */
+package object shadowsocks {
+  def ThrowableFuture[T](f: => T) = Future(f) onFailure {
+    case e: Throwable => e.printStackTrace()
+  }
+}
diff --git a/src/main/scala/com/github/shadowsocks/preferences/NatSwitchPreference.scala b/src/main/scala/com/github/shadowsocks/preferences/NatSwitchPreference.scala
deleted file mode 100644
index 4471c329..00000000
--- a/src/main/scala/com/github/shadowsocks/preferences/NatSwitchPreference.scala
+++ /dev/null
@@ -1,27 +0,0 @@
-package com.github.shadowsocks.preferences
-
-import android.content.Context
-import android.content.res.TypedArray
-import android.preference.SwitchPreference
-import android.util.AttributeSet
-import com.github.shadowsocks.{R, ShadowsocksApplication}
-
-/**
-  * TODO: No animations?
-  * @author Mygod
-  */
-final class NatSwitchPreference(context: Context, attrs: AttributeSet) extends SwitchPreference(context, attrs) {
-  private var disabled = false
-
-  override def isEnabled = super.isEnabled && !disabled
-  override def setEnabled(b: Boolean) = super.setEnabled(b && !disabled)
-
-  if (!ShadowsocksApplication.isRoot) {
-    disabled = true
-    setEnabled(false)
-    setSummary(R.string.nat_summary_no_root)
-  }
-
-  override def onGetDefaultValue(a: TypedArray, index: Int) =
-    (!ShadowsocksApplication.isVpnEnabled).asInstanceOf[AnyRef]
-}
diff --git a/src/main/scala/com/github/shadowsocks/utils/Console.scala b/src/main/scala/com/github/shadowsocks/utils/Console.scala
index 60edd8f7..042dc9ff 100644
--- a/src/main/scala/com/github/shadowsocks/utils/Console.scala
+++ b/src/main/scala/com/github/shadowsocks/utils/Console.scala
@@ -75,17 +75,11 @@ object Console {
     shell.close()
   }
 
-  def runRootCommand(command: String): String = runRootCommand(Array(command))
-  def runRootCommand(command: String, context: String): String = runRootCommand(Array(command), context)
-  def runRootCommand(commands: Array[String]): String = runRootCommand(commands, "u:r:init_shell:s0")
-
-  def runRootCommand(commands: Array[String], context: String): String = {
-    if (!isRoot) {
-      return null
-    }
-    val shell = openRootShell(context)
+  def runRootCommand(commands: String*): String = runRootCommand(commands.toArray)
+  def runRootCommand(commands: Array[String]): String = {
+    val shell = openRootShell("u:r:init_shell:s0")
     val sb = new StringBuilder
-    shell.addCommand(commands, 0, ((commandCode: Int, exitCode: Int, output: util.List[String]) => {
+    shell.addCommand(commands, 0, ((_, exitCode, output) => {
       if (exitCode < 0) {
         shell.close()
       } else {
diff --git a/src/main/scala/com/github/shadowsocks/utils/Utils.scala b/src/main/scala/com/github/shadowsocks/utils/Utils.scala
index f0f7301d..3754efaa 100644
--- a/src/main/scala/com/github/shadowsocks/utils/Utils.scala
+++ b/src/main/scala/com/github/shadowsocks/utils/Utils.scala
@@ -140,12 +140,14 @@ object Utils {
   }
 
   // Blocked > 3 seconds
-  def toggleAirplaneMode(context: Context) {
-    if (ShadowsocksApplication.isRoot) {
-      Console.runRootCommand(Array("ndc resolver flushdefaultif", "ndc resolver flushif wlan0"))
+  def toggleAirplaneMode(context: Context) = {
+    if (Console.isRoot) {
+      Console.runRootCommand("ndc resolver flushdefaultif", "ndc resolver flushif wlan0")
+      true
     } else if (Build.VERSION.SDK_INT < 17) {
       toggleBelowApiLevel17(context)
-    }
+      true
+    } else false
   }
 
   //noinspection ScalaDeprecation
@@ -305,8 +307,7 @@ object Utils {
     var compatible: Boolean = false
     var version: Boolean = false
 
-    val command = Array(iptables + " --version", iptables + " -L -t nat -n")
-    val lines = Console.runRootCommand(command)
+    val lines = Console.runRootCommand(iptables + " --version", iptables + " -L -t nat -n")
     if (lines == null) return
 
     if (lines.contains("OUTPUT")) {
@@ -384,9 +385,7 @@ object Utils {
     hasRedirectSupport = 1
 
     val command = Utils.getIptables + " -t nat -A OUTPUT -p udp --dport 54 -j REDIRECT --to 8154"
-    val lines = Console.runRootCommand(command)
-
-    Console.runRootCommand(command.replace("-A", "-D"))
+    val lines = Console.runRootCommand(command, command.replace("-A", "-D"))
     if (lines == null) return
     if (lines.contains("No chain/target/match")) {
       hasRedirectSupport = 0