use "SIGNAL HUP" to request Tor re-read its config

The tor daemon supports both "SIGNAL HUP" via its control port or the UNIX
signal `kill -HUP` via the terminal as a way to trigger the tor daemon to
reload its config.  This is needed for new bridges and hidden services. It
is not necessary to restart everything to add those.

https://stem.torproject.org/faq.html#how-do-i-reload-my-torrc

src/org/torproject/android/OrbotMainActivity.java

@@ -479,12 +479,10 @@ public class OrbotMainActivity extends Activity implements OrbotConstants, OnLon
 
 		if (onionHostname == null || onionHostname.length() == 0)
 		{
-			stopTor();			
+			requestTorRereadConfig();
-			startTor();
 
 			new Thread () {
 
-			
 			    public void run ()
 				{
 					String onionHostname = mPrefs.getString("pref_hs_hostname","");
@@ -945,37 +943,13 @@ public class OrbotMainActivity extends Activity implements OrbotConstants, OnLon
 			String bridgeList = Prefs.getBridgesList();
 			if (bridgeList != null && bridgeList.length() > 0)
 			{
-				restartTor ();
+				requestTorRereadConfig ();
 			}
-			
 		}
     }
     
-    private void restartTor ()
+    private void requestTorRereadConfig()    {
-    {
+        sendIntentToService (TorServiceConstants.CMD_START);
-    	try
-		{
-			//do auto restart
-			stopTor ();
-			
-			mStatusUpdateHandler.postDelayed(new Runnable () {
-				public void run ()
-				{
-					try 
-					{
-						startTor();
-					}
-					catch (Exception e)
-					{
-						Log.e(TAG,"can't start orbot",e);
-					}
-				}
-			}, 2000);
-		}
-		catch (Exception e)
-		{
-			Log.e(TAG,"can't stop orbot",e);
-		}
     }
     
     public void promptStartVpnService ()

src/org/torproject/android/service/TorService.java

@@ -344,6 +344,8 @@ public class TorService extends Service implements TorServiceConstants, OrbotCon
                 if (action.equals(CMD_START)) {
                     startTor();
                     // stopTor() is called when the Service is destroyed
+                } else if (action.equals(CMD_SIGNAL_HUP)) {
+                    requestTorRereadConfig();
                 } else if (action.equals(CMD_NEWNYM)) {
                     newIdentity();
                 } else if (action.equals(CMD_FLUSH)) {
@@ -534,7 +536,28 @@ public class TorService extends Service implements TorServiceConstants, OrbotCon
         }
     }
 
+    private void requestTorRereadConfig() {
+        try {
+            conn.signal("HUP");
+            return;
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+        // if that fails, try again using native utils
+        try {
+            killProcess(fileTor, "-1"); // this is -HUP
+        } catch (CannotKillException e) {
+            e.printStackTrace();
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+    }
+
     private void killProcess(File fileProcBin) throws IOException, CannotKillException {
+        killProcess(fileProcBin, "-9"); // this is -KILL
+    }
+
+    private void killProcess(File fileProcBin, String signal) throws IOException, CannotKillException {
         int procId = -1;
         int killAttempts = 0;
 
@@ -554,10 +577,10 @@ public class TorService extends Service implements TorServiceConstants, OrbotCon
             } else {
                 shell = Shell.startShell();
             }
-            shell.add(new SimpleCommand("busybox killall " + fileProcBin.getName()));
+            shell.add(new SimpleCommand("busybox killall " + signal + " " + fileProcBin.getName()));
-            shell.add(new SimpleCommand("toolbox kill -9 " + pidString));
+            shell.add(new SimpleCommand("toolbox kill " + signal + " " + pidString));
-            shell.add(new SimpleCommand("busybox kill -9 " + pidString));
+            shell.add(new SimpleCommand("busybox kill " + signal + " " + pidString));
-            shell.add(new SimpleCommand("kill -9 " + pidString));
+            shell.add(new SimpleCommand("kill " + signal + " " + pidString));
             try {
                 Thread.sleep(1000);
             } catch (InterruptedException e) {

src/org/torproject/android/service/TorServiceConstants.java

@@ -84,6 +84,7 @@ public interface TorServiceConstants {
     public static final int LOG_MSG = 4;
     
     public static final String CMD_START = "start";
+    public static final String CMD_SIGNAL_HUP = "signal_hup";
     public static final String CMD_FLUSH = "flush";
     public static final String CMD_NEWNYM = "newnym";
     public static final String CMD_VPN = "vpn";