System Permissions for APP

If a third-party application wants to obtain system permissions, it needs to declare its UID as a system process in the AndroidManifest.xml file, and the application needs to be signed with the platform key (signature).

Declare UID as a System Process

The third-party application’s AndroidManifest.xml must include:

1
android:sharedUserid="android.uid.system"

Sign APP with Platform Key

APP Signing for SDK Source Code

  1. Put the APK in the application directory, and create an Android.mk file containing the following contents:

    1
    2
    3
    4
    5
    6
    7
    8
    9
    10
    11
    12
    13
    14
    15
    16
    LOCAL_PATH := $(call my-dir)
    include $(CLEAR_VARS)
    # module name should match the apk name
    LOCAL_MODULE := XXXX
    LOCAL_MODULE_TAGS := optional

    LOCAL_SRC_FILES := $(LOCAL_MODULE).apk
    LOCAL_MODULE_CLASS := APPS
    LOCAL_MODULE_SUFFIX := $(COMMON_ANDROID_PACKAGE_SUFFIX)
    LOCAL_PRIVILEGED_MODULE := true

    # use the application's own signature
    # LOCAL_CERTIFICATE := PRESIGNED
    # sign with the platform key
    LOCAL_CERTIFICATE := platform
    include $(BUILD_PREBUILT)

  2. Add the name of your APK XXXX into the compile file.

    1
    2
    3
    PRODUCT_PACKAGES +=\
       Bluetooth \
       XXXX

  3. Recompile the SDK, and the APK file will be generated in the out directory, containing the platform key.

APP Signing for Windows & Linux PC

  1. According to your SBC model and system version, download the two platform key files platform.x509.pem and platform.pk8.

  2. Download the Java Signing Tool signapk.jar.

  3. Download the library-dependency libconscrypt_openjdk_jni.so and put it in the signlib directory.

  4. Install the JDK Tool.

  5. Execute the shell command:

    1
    java -Djava.library.path=signlib -jar signapk.jar platform.x509.pem platform.pk8 unsigned.apk signed.apk
Next