Kill RootSession on low memory

mobile/src/main/java/be/mygod/vpnhotspot/App.kt

@@ -12,6 +12,7 @@ import android.preference.PreferenceManager
 import androidx.core.content.getSystemService
 import be.mygod.vpnhotspot.util.DeviceStorageApp
 import be.mygod.vpnhotspot.util.Event0
+import be.mygod.vpnhotspot.util.RootSession
 import com.crashlytics.android.Crashlytics
 import io.fabric.sdk.android.Fabric
 
@@ -39,6 +40,11 @@ class App : Application() {
         ServiceNotification.updateNotificationChannels()
     }
 
+    override fun onTrimMemory(level: Int) {
+        super.onTrimMemory(level)
+        if (level >= TRIM_MEMORY_RUNNING_CRITICAL) RootSession.trimMemory()
+    }
+
     lateinit var deviceStorage: Application
     val handler = Handler()
     val pref: SharedPreferences by lazy { PreferenceManager.getDefaultSharedPreferences(deviceStorage) }

mobile/src/main/java/be/mygod/vpnhotspot/util/RootSession.kt

@@ -46,6 +46,12 @@ class RootSession : AutoCloseable {
             instance.haltTimeout()
             return instance.Transaction()
         }
+
+        fun trimMemory() = monitor.withLock {
+            val instance = instance ?: return
+            instance.haltTimeout()
+            instance.close()
+        }
     }
 
     class UnexpectedOutputException(msg: String) : RuntimeException(msg)