Settings: add version

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

app/src/main/java/com/wireguard/android/util/ToolsInstaller.java

@@ -10,6 +10,7 @@ import android.content.Context;
 import android.system.OsConstants;
 import android.util.Log;
 
+import com.wireguard.android.Application;
 import com.wireguard.android.Application.ApplicationContext;
 import com.wireguard.android.Application.ApplicationScope;
 import com.wireguard.android.util.RootShell.NoRootException;
@@ -17,11 +18,14 @@ import com.wireguard.android.util.RootShell.NoRootException;
 import java.io.File;
 import java.io.FileNotFoundException;
 import java.io.IOException;
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 
 import javax.inject.Inject;
 
+import java9.util.concurrent.CompletionStage;
+
 /**
  * Helper to install WireGuard tools to the system partition.
  */
@@ -52,6 +56,15 @@ public final class ToolsInstaller {
         this.rootShell = rootShell;
     }
 
+    public CompletionStage<String> getVersion() {
+        return Application.getComponent().getAsyncWorker().supplyAsync(() -> {
+            final ArrayList<String> output = new ArrayList<>();
+            if (rootShell.run(output, "cat /sys/module/wireguard/version") != 0 || output.isEmpty())
+                throw new RuntimeException("Unable to determine kernel module version");
+            return output.get(0);
+        });
+    }
+
     private static File getInstallDir() {
         final String path = System.getenv("PATH");
         if (path == null)