platform_bootable_recovery/updater_sample

SystemUpdaterSample

This app demonstrates how to use Android system updates APIs to install OTA updates. It contains a sample client for update_engine to install A/B (seamless) updates and a sample of applying non-A/B updates using recovery.

A/B (seamless) update is available since Android Nougat (API 24), but this sample targets the latest android.

Workflow

SystemUpdaterSample app shows list of available updates on the UI. User is allowed to select an update and apply it to the device. App shows installation progress, logs can be found in adb logcat. User can stop or reset an update. Resetting the update requests update engine to cancel any ongoing update, and revert if the update has been applied. Stopping does not revert the applied update.

Update Config file

In this sample updates are defined in JSON update config files. The structure of a config file is defined in com.example.android.systemupdatersample.UpdateConfig, example file is located at res/raw/sample.json.

In real-life update system the config files expected to be served from a server to the app, but in this sample, the config files are stored on the device. The directory can be found in logs or on the UI. In most cases it should be located at /data/user/0/com.example.android.systemupdatersample/files/configs/.

SystemUpdaterSample app downloads OTA package from url. If ab_install_type is NON_STREAMING then app downloads the whole package and passes it to the update_engine. If ab_install_type is STREAMING then app downloads only some files to prepare the streaming update and update_engine will stream only payload.bin. To support streaming A/B (seamless) update, OTA package file must be an uncompressed (ZIP_STORED) zip file.

Config files can be generated using tools/gen_update_config.py. Running ./tools/gen_update_config.py --help shows usage of the script.

Running on a device

The commands expected to be run from $ANDROID_BUILD_TOP.

1. Compile the app $ mmma bootable/recovery/updater_sample.
2. Install the app to the device using $ adb install <APK_PATH>.
3. Add update config files.

Development

• Create a UI with list of configs, current version, control buttons, progress bar and log viewer
• Add PayloadSpec and PayloadSpecs for working with update zip file
• Add UpdateConfig for working with json config files
• Add applying non-streaming update
• Prepare streaming update (partially downloading package)
• Add applying streaming update
• Add tests for MainActivity
• Add stop/reset the update
• Verify system partition checksum for package
• HAL compatibility check
• Change partition demo
• Add non-A/B updates demo

Running tests

1. Build $ mmma bootable/recovery/updater_sample/
2. Install app $ adb install $OUT/system/app/SystemUpdaterSample/SystemUpdaterSample.apk
3. Install tests $ adb install $OUT/testcases/SystemUpdaterSampleTests/SystemUpdaterSampleTests.apk
4. Run tests $ adb shell am instrument -w com.example.android.systemupdatersample.tests/android.support.test.runner.AndroidJUnitRunner
5. Run a test file

   $ adb shell am instrument \
     -w com.example.android.systemupdatersample.tests/android.support.test.runner.AndroidJUnitRunner \
     -c com.example.android.systemupdatersample.util.PayloadSpecsTest
   

Getting access to update_engine API and read/write access to /data

Run adb shell as a root, and set SELinux mode to permissive (0):

$ adb root
$ adb shell
# setenforce 0
# getenforce