Ask for ROOT only when it's needed

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 {

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