commit | 648818d976c2d19d355c0cff1af0281cc263db03 | [log] [tgz] |
---|---|---|
author | Xin Li <delphij@google.com> | Wed Oct 06 22:55:14 2021 +0000 |
committer | Xin Li <delphij@google.com> | Wed Oct 06 22:55:14 2021 +0000 |
tree | 38a3ff474ccf37bc78e3804c7e8f2bb74df0df93 | |
parent | 9739792fa160eb944998935554624b04c188c66e [diff] | |
parent | b37033fcd2980092261f3cc893740866f73a667f [diff] |
Merge Android 12 Bug: 202323961 Merged-In: I3582a4714e6a3f1f29424b96f6b24b3b4e73783e Change-Id: I07195926007b65ecc0633933d83cdf5e2fe1b291
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.
TODO: explain inputs (e.g. /system/etc/public.libraries.txt, /apex/apex-info-list.xml, ..)
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.
A linker configuration file(linker.config.json) is compiled into a protobuf at build time by conv_linker_config
. You can find the compiled file under <base>/etc/linker.config.pb
. For example, /apex/com.android.art/etc/linker.config.pb
is a configuration for the com.android.art
APEX.
/system/etc/linker.config.pb
(or its source module system_linker_config
) is special because its provideLibs
key is generated at build time.
linker.config.json file is in json format which can contain properties as below.
Property Name | Type | Description | Allowed module |
---|---|---|---|
permittedPaths | List | Additional permitted paths | APEX |
visible | bool | Force APEX namespace to be visible from all sections if the value is true | APEX |
provideLibs | List | Libraries providing from the module | System |
requireLibs | List | Libraries required from the module | System |
{ "permittedPaths" : [ "/a", "/b/c", "/d/e/f"], "visible": true }
{ "provideLibs" : [ "a.so", "b.so", "c.so" ], "requireLibs" : [ "foo.so", "bar.so", "baz.so" ] }
TODO: a few words about the files
Check ld.config.format.md.
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.tag
is jni
, library_list
is the list of JNI libraries exposed by apex_namespace
.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.