Verify if APEX has any link with all libs allowed

APEX modules should link to other namespaces with exact library list
rather than just allowing all libs to keep track of dependencies. This
change verifies if there are any APEX (except ART) which contains link
with all libs allowed.

Bug: 159302165
Test: atest passed
Change-Id: Ifdd7de179f8d420ec548b8ab11fcd137ceb1a3aa
5 files changed
tree: 847c3ecff57c249844bf1b4817c21b17910cc433
  1. contents/
  2. generator/
  3. modules/
  4. testdata/
  5. testmodules/
  6. .clang-format
  7. .gitignore
  8. Android.bp
  9. linkerconfig_diff_test.xml
  10. main.cc
  11. OWNERS
  12. PREUPLOAD.cfg
  13. README.md
  14. rundiff.sh
  15. TEST_MAPPING
README.md

LinkerConfig

Introduction

Linkerconfig is a program to generate linker configuration based on the runtime environment. Linkerconfig generates one or more ld.config.txt files and some other files under /linkerconfig during init. Linker will read this generated configuration file(s) to find out link relationship between libraries and executable.

Inputs

TODO: explain inputs (e.g. /system/etc/public.libraries.txt, /apex/apex-info-list.xml, ..)

linker.config.json

Linker configuration file can be used to add extra information while linkerconfig creates linker configuration with the module. This module can be defined as 'linker_config' from Soong, and it will be translated as protobuf file at build time.

Format

linker.config.json file is in json format which can contain properties as below.

Property NameTypeDescription
permittedPathsListAdditional permitted paths
visibleboolForce APEX namespace to be visible from all sections if the value is true

Example

{
    "permittedPaths" : [ "/a", "/b/c", "/d/e/f"],
    "visible": true
}

Outputs

/linkerconfig/ld.config.txt & /linkerconfig/*/ld.config.txt

TODO: a few words about the files

Check ld.config.format.md.

/linkerconfig/apex.libraries.txt

The file describes libraries exposed from APEXes. libnativeloader is the main consumer of this file.

# comment line
jni com_android_foo libfoo_jni.so
public com_android_bar libbar.so:libbaz.so

The file is line-based and each line consists of tag apex_namespace library_list.

  • tag explains what library_list is.
  • apex_namespace is the namespace of the apex. Note that it is mangled like com_android_foo for the APEX("com.android.foo").
  • library_list is colon-separated list of library names.
    • if tag is jni, library_list is the list of JNI libraries exposed by apex_namespace.
    • if tag is public, library_list is the list of public libraries exposed by apex_namespace. Here, public libraries are the libs listed in /system/etc/public.libraries.txt.