android: add simple support library to communicate with the host service

android/Android.mk

@@ -1,6 +1,20 @@
 LOCAL_PATH:= $(call my-dir)
 include $(CLEAR_VARS)
 
+LOCAL_MODULE_TAGS := optional
+LOCAL_SRC_FILES = \
+	jni/anbox_support.cpp
+LOCAL_C_INCLUDES := \
+	$(JNI_H_INCLUDE) \
+	libcore/include
+LOCAL_SHARED_LIBRARIES := \
+	liblog
+LOCAL_MODULE := libanbox_support
+
+include $(BUILD_SHARED_LIBRARY)
+
+include $(CLEAR_VARS)
+
 LOCAL_MODULE_TAGS := optional
 LOCAL_AIDL_INCLUDES := $(LOCAL_PATH)/src/java
 LOCAL_SRC_FILES := $(call all-java-files-under, java)

android/java/org/anbox/MainApplication.java

@@ -5,6 +5,12 @@ import android.app.Application;
 public class MainApplication extends Application {
     private NavBar mNavBar;
 
+    static {
+        // Load our native support library on startup so we get
+        // access to several things from the Anbox host service.
+        System.loadLibrary("anbox_support");
+    }
+
     public void startServices() {
         mNavBar = new NavBar(this);
     }

android/jni/anbox_support.cpp

@@ -0,0 +1,29 @@
+/*
+ * Copyright (C) 2016 Simon Fels <morphis@gravedo.de>
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 3, as published
+ * by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranties of
+ * MERCHANTABILITY, SATISFACTORY QUALITY, or FITNESS FOR A PARTICULAR
+ * PURPOSE.  See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include <JNIHelp.h>
+#include <jni.h>
+
+#define LOG_TAG "AnboxSupport"
+
+#include <utils/Log.h>
+
+extern "C" jint JNI_OnLoad(JavaVM* vm, void* reserved) {
+    ALOGI("Successfully loaded Anbox support library");
+
+    return JNI_VERSION_1_4;
+}