Added option to run syncthing as root (fixes #48).

build.gradle

@@ -19,13 +19,15 @@ apply plugin: 'com.github.ben-manes.versions'
 repositories {
     mavenCentral()
     maven {
-        url {
+        url 'https://raw.github.com/kolavar/android-support-v4-preferencefragment/master/maven-repository/'
-            'https://raw.github.com/kolavar/android-support-v4-preferencefragment/master/maven-repository/'
     }
+    maven {
+        url 'http://jcenter.bintray.com'
     }
 }
 
 dependencies {
+    compile 'eu.chainfire:libsuperuser:1.0.0.201504231659'
     compile 'com.android.support:appcompat-v7:22.0.0'
     compile 'com.android.support:support-v4-preferencefragment:1.0.0@aar'
     androidTestCompile 'com.squareup.okhttp:mockwebserver:2.3.0'

src/main/java/com/nutomic/syncthingandroid/fragments/SettingsFragment.java

@@ -25,6 +25,8 @@ import com.nutomic.syncthingandroid.activities.SyncthingActivity;
 import com.nutomic.syncthingandroid.syncthing.RestApi;
 import com.nutomic.syncthingandroid.syncthing.SyncthingService;
 
+import eu.chainfire.libsuperuser.Shell;
+
 public class SettingsFragment extends PreferenceFragment
         implements SyncthingActivity.OnServiceConnectedListener,
         SyncthingService.OnApiChangeListener, Preference.OnPreferenceChangeListener,
@@ -126,6 +128,7 @@ public class SettingsFragment extends PreferenceFragment
         mSyncOnlyCharging = (CheckBoxPreference)
                 findPreference(SyncthingService.PREF_SYNC_ONLY_CHARGING);
         mSyncOnlyWifi = (CheckBoxPreference) findPreference(SyncthingService.PREF_SYNC_ONLY_WIFI);
+        Preference useRoot = findPreference(SyncthingService.PREF_USE_ROOT);
         Preference appVersion = screen.findPreference(APP_VERSION_KEY);
         mOptionsScreen = (PreferenceScreen) screen.findPreference(SYNCTHING_OPTIONS_KEY);
         mGuiScreen = (PreferenceScreen) screen.findPreference(SYNCTHING_GUI_KEY);
@@ -143,6 +146,10 @@ public class SettingsFragment extends PreferenceFragment
         mAlwaysRunInBackground.setOnPreferenceChangeListener(this);
         mSyncOnlyCharging.setOnPreferenceChangeListener(this);
         mSyncOnlyWifi.setOnPreferenceChangeListener(this);
+        if (!Shell.SU.available()) {
+            screen.removePreference(useRoot);
+        }
+        useRoot.setOnPreferenceChangeListener(this);
         screen.findPreference(EXPORT_CONFIG).setOnPreferenceClickListener(this);
         screen.findPreference(IMPORT_CONFIG).setOnPreferenceClickListener(this);
         screen.findPreference(SYNCTHING_RESET).setOnPreferenceClickListener(this);
@@ -234,23 +241,25 @@ public class SettingsFragment extends PreferenceFragment
                     RestApi.TYPE_GUI, preference.getKey(), o, false, getActivity());
         }
 
+        boolean requireRestart = false;
+
         // Avoid any code injection.
         int error = 0;
         if (preference.getKey().equals(STTRACE)) {
             if (((String) o).matches("[a-z, ]*"))
-                mSyncthingService.getApi().requireRestart(getActivity());
+                requireRestart = true;
             else
                 error = R.string.toast_invalid_sttrace;
         } else if (preference.getKey().equals(GUI_USER)) {
             String s = (String) o;
             if (!s.contains(":") && !s.contains("'"))
-                mSyncthingService.getApi().requireRestart(getActivity());
+                requireRestart = true;
             else
                 error = R.string.toast_invalid_username;
         } else if (preference.getKey().equals(GUI_PASSWORD)) {
             String s = (String) o;
             if (!s.contains(":") && !s.contains("'"))
-                mSyncthingService.getApi().requireRestart(getActivity());
+                requireRestart = true;
             else
                 error = R.string.toast_invalid_password;
         }
@@ -259,6 +268,13 @@ public class SettingsFragment extends PreferenceFragment
             return false;
         }
 
+        if (preference.getKey().equals(SyncthingService.PREF_USE_ROOT))
+            requireRestart = true;
+
+        if (requireRestart)
+            mSyncthingService.getApi().requireRestart(getActivity());
+
+
         return true;
     }
 

src/main/java/com/nutomic/syncthingandroid/syncthing/RestApi.java

@@ -267,7 +267,7 @@ public class RestApi implements SyncthingService.OnWebGuiAvailableListener,
     }
 
     /**
-     * Stops syncthing. You should probably use SyncthingService.stopService() instead.
+     * Stops syncthing and cancels notification. For use by {@link SyncthingService}.
      */
     public void shutdown() {
         // Happens in unit tests.
@@ -277,7 +277,6 @@ public class RestApi implements SyncthingService.OnWebGuiAvailableListener,
         NotificationManager nm = (NotificationManager)
                 mContext.getSystemService(Context.NOTIFICATION_SERVICE);
         nm.cancel(NOTIFICATION_RESTART);
-        SyncthingRunnable.killSyncthing();
         mRestartPostponed = false;
     }
 
@@ -740,7 +739,7 @@ public class RestApi implements SyncthingService.OnWebGuiAvailableListener,
             case "":         return c.getString(R.string.state_unknown);
         }
         if (BuildConfig.DEBUG) {
-            throw new AssertionError("Unexpected folder state");
+            throw new AssertionError("Unexpected folder state " + state);
         }
         return "";
     }

src/main/java/com/nutomic/syncthingandroid/syncthing/SyncthingRunnable.java

@@ -5,6 +5,7 @@ import android.content.Intent;
 import android.content.SharedPreferences;
 import android.os.Environment;
 import android.preference.PreferenceManager;
+import android.text.TextUtils;
 import android.util.Log;
 
 import java.io.BufferedReader;
@@ -15,6 +16,8 @@ import java.io.InputStreamReader;
 import java.util.Map;
 import java.util.concurrent.atomic.AtomicReference;
 
+import eu.chainfire.libsuperuser.Shell;
+
 /**
  * Runs the syncthing binary from command line, and prints its output to logcat.
  */
@@ -88,7 +91,6 @@ public class SyncthingRunnable implements Runnable {
         try {
             ProcessBuilder pb = new ProcessBuilder("chmod", "+x", mSyncthingBinary);
             Process p = pb.start();
-            if (p != null)
             p.waitFor();
         } catch (IOException|InterruptedException e) {
             Log.w(TAG, "Failed to chmod Syncthing", e);
@@ -98,7 +100,10 @@ public class SyncthingRunnable implements Runnable {
         try {
             // Loop to handle Syncthing restarts (these always have an error code of 3).
             do {
-                ProcessBuilder pb = new ProcessBuilder(mCommand);
+                ProcessBuilder pb = (useRoot())
+                        ? new ProcessBuilder("su", "-c", TextUtils.join(" ", mCommand))
+                        : new ProcessBuilder(mCommand);
+
                 Map<String, String> env = pb.environment();
                 // Set home directory to data folder for web GUI folder picker.
                 env.put("HOME", Environment.getExternalStorageDirectory().getAbsolutePath());
@@ -138,6 +143,14 @@ public class SyncthingRunnable implements Runnable {
         }
     }
 
+    /**
+     * Returns true if root is available and enabled in settings.
+     */
+    private boolean useRoot() {
+        SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(mContext);
+        return sp.getBoolean(SyncthingService.PREF_USE_ROOT, false) && Shell.SU.available();
+    }
+
     /**
      * Look for a running libsyncthing.so process and nice its IO.
      */
@@ -149,7 +162,7 @@ public class SyncthingRunnable implements Runnable {
                 int ret = 1;
                 try {
                     Thread.sleep(1000); // Wait a second before getting the pid
-                    nice = Runtime.getRuntime().exec("sh");
+                    nice = Runtime.getRuntime().exec((useRoot()) ? "su" : "sh");
                     niceOut = new DataOutputStream(nice.getOutputStream());
                     niceOut.writeBytes("set `ps | grep libsyncthing.so`\n");
                     niceOut.writeBytes("ionice $2 be 7\n"); // best-effort, low priority
@@ -182,9 +195,8 @@ public class SyncthingRunnable implements Runnable {
     /**
      * Look for running libsyncthing.so processes and kill them.
      * Try a SIGTERM once, then try again (twice) with SIGKILL.
-     *
      */
-    public static void killSyncthing() {
+    public void killSyncthing() {
         final Process p = mSyncthing.get();
         if (p != null) {
             mSyncthing.set(null);
@@ -201,7 +213,7 @@ public class SyncthingRunnable implements Runnable {
             Process ps = null;
             DataOutputStream psOut = null;
             try {
-                ps = Runtime.getRuntime().exec("sh");
+                ps = Runtime.getRuntime().exec((useRoot()) ? "su" : "sh");
                 psOut = new DataOutputStream(ps.getOutputStream());
                 psOut.writeBytes("ps | grep libsyncthing.so\n");
                 psOut.writeBytes("exit\n");

src/main/java/com/nutomic/syncthingandroid/syncthing/SyncthingService.java

@@ -92,6 +92,8 @@ public class SyncthingService extends Service {
 
     public static final String PREF_SYNC_ONLY_CHARGING = "sync_only_charging";
 
+    public static final String PREF_USE_ROOT = "use_root";
+
     private static final int NOTIFICATION_ACTIVE = 1;
 
     private ConfigXml mConfig;
@@ -142,6 +144,8 @@ public class SyncthingService extends Service {
 
     private DeviceStateHolder mDeviceStateHolder;
 
+    private SyncthingRunnable mRunnable;
+
     /**
      * Handles intents, either {@link #ACTION_RESTART}, or intents having
      * {@link DeviceStateHolder#EXTRA_HAS_WIFI} or {@link DeviceStateHolder#EXTRA_IS_CHARGING}
@@ -153,11 +157,11 @@ public class SyncthingService extends Service {
             return START_STICKY;
 
         if (ACTION_RESTART.equals(intent.getAction()) && mCurrentState == State.ACTIVE) {
-            mApi.shutdown();
+            shutdown();
             mCurrentState = State.INIT;
             updateState();
         } else if (ACTION_RESET.equals(intent.getAction())) {
-            mApi.shutdown();
+            shutdown();
             new SyncthingRunnable(this, SyncthingRunnable.Command.reset).run();
             mCurrentState = State.INIT;
             updateState();
@@ -203,14 +207,15 @@ public class SyncthingService extends Service {
             // HACK: Make sure there is no syncthing binary left running from an improper
             // shutdown (eg Play Store update).
             // NOTE: This will log an exception if syncthing is not actually running.
-            mApi.shutdown();
+            shutdown();
 
             Log.i(TAG, "Starting syncthing according to current state and preferences");
             mConfig = new ConfigXml(SyncthingService.this);
             mCurrentState = State.STARTING;
             registerOnWebGuiAvailableListener(mApi);
             new PollWebGuiAvailableTaskImpl(getFilesDir() + "/" + HTTPS_CERT_FILE).execute(mConfig.getWebGuiUrl());
-            new Thread(new SyncthingRunnable(this, SyncthingRunnable.Command.main)).start();
+            mRunnable = new SyncthingRunnable(this, SyncthingRunnable.Command.main);
+            new Thread(mRunnable).start();
             Notification n = new NotificationCompat.Builder(this)
                     .setContentTitle(getString(R.string.syncthing_active))
                     .setSmallIcon(R.drawable.ic_stat_notify)
@@ -229,14 +234,7 @@ public class SyncthingService extends Service {
             Log.i(TAG, "Stopping syncthing according to current state and preferences");
             mCurrentState = State.DISABLED;
 
-            if (mApi != null) {
+            shutdown();
-                mApi.shutdown();
-                for (FolderObserver ro : mObservers) {
-                    ro.stopWatching();
-                }
-                mObservers.clear();
-            }
-            nm.cancel(NOTIFICATION_ACTIVE);
         }
         onApiChange();
     }
@@ -331,11 +329,23 @@ public class SyncthingService extends Service {
     public void onDestroy() {
         super.onDestroy();
         Log.i(TAG, "Shutting down service");
-        if (mApi != null) {
+        shutdown();
-            mApi.shutdown();
     }
+
+    private void shutdown() {
+        if (mRunnable != null)
+            mRunnable.killSyncthing();
+
+        if (mApi != null)
+            mApi.shutdown();
+
         NotificationManager nm = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
         nm.cancel(NOTIFICATION_ACTIVE);
+
+        for (FolderObserver ro : mObservers) {
+            ro.stopWatching();
+        }
+        mObservers.clear();
     }
 
     /**
@@ -400,7 +410,7 @@ public class SyncthingService extends Service {
             if (mStopScheduled) {
                 mCurrentState = State.DISABLED;
                 onApiChange();
-                mApi.shutdown();
+                shutdown();
                 mStopScheduled = false;
                 return;
             }

src/main/res/xml/app_settings.xml

@@ -25,6 +25,12 @@
             android:summary="@string/advanced_folder_picker_summary"
             android:defaultValue="false" />
 
+        <CheckBoxPreference
+            android:key="use_root"
+            android:title="Sync as root"
+            android:summary="Run syncthing as superuser"
+            android:defaultValue="false" />
+
     </PreferenceCategory>
 
     <PreferenceCategory