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android / platform / packages / modules / SdkExtensions / 964cb37e579a3718dc47185c456782b4382faa45
commit964cb37e579a3718dc47185c456782b4382faa45[log] [tgz]
authorAnton Hansson <[email protected]>Wed Feb 22 06:27:01 2023 +0000
committerAutomerger Merge Worker <[email protected]>Wed Feb 22 06:27:01 2023 +0000
treee028f98a0462cfce5f1cd91075c69adf1da17e5d
parentc8fea35c68e1828a2daca7ba3c8623c38f8c6a8b [diff]
parenteeb588f50952d3785fb1666c4745e8929c68de64 [diff]
Fix extension keys test for 2022-11 on Go am: ef6438843c am: 75ccb0b76a am: eeb588f509

Original change: https://android-review.googlesource.com/c/platform/packages/modules/SdkExtensions/+/2446453

Change-Id: Iac72389cb6b727768ae5bdb2cdd556ca645df0e6
Signed-off-by: Automerger Merge Worker <[email protected]>
tree: e028f98a0462cfce5f1cd91075c69adf1da17e5d
  1. derive_classpath/
  2. derive_sdk/
  3. gen_sdk/
  4. java/
  5. javatests/
  6. Android.bp
  7. com.android.sdkext.avbpubkey
  8. com.android.sdkext.pem
  9. com.android.sdkext.pk8
  10. com.android.sdkext.x509.pem
  11. manifest.json
  12. OWNERS
  13. PREUPLOAD.cfg
  14. README.md
  15. TEST_MAPPING
README.md

SdkExtensions module

SdkExtensions module is responsible for:

  • deciding the extension SDK level of the device;
  • providing APIs for applications to query the extension SDK level;
  • determining the values for the BOOTCLASSPATH, DEX2OATBOOTCLASSPATH, and SYSTEMSERVERCLASSPATH environment variables.

General information

Structure

The module is packaged in an apex, com.android.sdkext, and has several components:

  • bin/derive_classpath: a native binary that runs early in the device boot process. It reads individual classpath configs files from the system and other modules, merges them, and defines the definition of *CLASSPATH environ variables.
  • bin/derive_sdk: native binary that runs early in the device boot process and reads metadata of other modules, to set system properties relating to the extension SDK (for instance build.version.extensions.r).
  • javalib/framework-sdkextension.jar: this is a jar on the bootclasspath that exposes APIs to applications to query the extension SDK level.

Deriving extension SDK level

derive_sdk is a program that reads metadata stored in other apex modules, in the form of binary protobuf files in subpath etc/sdkinfo.pb inside each apex. The structure of this protobuf can be seen here. The exact steps for converting a set of metadata files to actual extension versions is likely to change over time, and should not be depended upon.

Reading extension SDK level

The module exposes a java class SdkExtensions in the package android.os.ext. The method getExtensionVersion(int) can be used to read the version of a particular sdk extension, e.g. getExtensionVersion(Build.VERSION_CODES.R).

Deriving classpaths

derive_classpath service reads and merges individual config files in the /system/etc/classpaths/ and /apex/*/etc/classpaths. Each config stores protobuf message from classpaths.proto in a proto binary format. Exact merging algorithm that determines the order of the classpath entries is described in derive_classpath.cpp and may change over time.

Developer information

Adding a new extension

An extension is a way to group a set of modules so that they are versioned together. We currently define a new extension for every Android SDK level that introduces new modules. Every module shipped in previous versions are also part of the new extension. For example, all the R modules are part of both the R extensions and the S extensions.

The steps to define a new extension are:

  • Add any new modules to the SdkModule enum in sdk.proto.
  • Add the binary “current sdk version” proto to the apexes of the new modules.
  • Update derive_sdk.cpp by:
  • mapping the modules' package names to the new enum values
  • creating a new set with the new enum values of the modules relevant for this extension.
  • set a new sysprop to the value of GetSdkLevel with the new enum set
  • add a unit test to derive_sdk_test.cpp verifying the new extensions work
  • Make the SdkExtensions.getExtensionVersion API support the new extensions.
  • Extend the CTS test to verify the above two behaviors.