1# Linker config file format 2 3This document describes format of /system/etc/ld.config.txt file. This file can be used to customize 4linker-namespace setup for dynamic executables. 5 6## Overview 7 8The configuration consists of 2 parts 91. Mappings - maps executable locations to sections 102. Sections - contains linker-namespace configuration 11 12## Mappings 13 14This part of the document maps location of an executable to a section. Here is an example 15 16The format is `dir.<section_name>=<directory>` 17 18The mappings should be defined between start of ld.config.txt and the first section. 19 20## Section 21 22Every section starts with `[section_name]` (which is used in mappings) and it defines namespaces 23configuration using set of properties described in example below. 24 25## Example 26 27``` 28# The following line maps section to a dir. Binraies ran from this location will use namespaces 29# configuration specified in [example_section] below 30dir.example_section=/system/bin/example 31 32# Section starts 33[example_section] 34 35# When this flag is set to true linker will set target_sdk_version for this binary to 36# the version specified in <dirname>/.version file, where <dirname> = dirname(executable_path) 37# 38# default value is false 39enable.target.sdk.version = true 40 41# This property can be used to declare additional namespaces.Note that there is always the default 42# namespace. The default namespace is the namespace for the main executable. This list is 43# comma-separated. 44additional.namespaces = ns1 45 46# Each namespace property starts with "namespace.<namespace-name>" The following is configuration 47# for the default namespace 48 49# Is namespace isolated - the default value is false 50namespace.default.isolated = true 51 52# Default namespace search path. Note that ${LIB} here is substituted with "lib" for 32bit targets 53# and with "lib64" for 64bit ones. 54namespace.default.search.paths = /system/${LIB}:/system/other/${LIB} 55 56# ... same for asan 57namespace.default.asan.search.paths = /data/${LIB}:/data/other/${LIB} 58 59# Permitted path 60namespace.default.permitted.paths = /system/${LIB} 61 62# ... asan 63namespace.default.asan.permitted.paths = /data/${LIB} 64 65# This declares linked namespaces - comma separated list. 66namespace.default.links = ns1 67 68# For every link define list of shared libraries. This is list of the libraries accessilbe from 69# default namespace but loaded in the linked namespace. 70namespace.default.link.ns1.shared_libs = libexternal.so:libother.so 71 72# This part defines config for ns1 73namespace.ns1.isolated = true 74namespace.ns1.search.paths = /vendor/${LIB} 75namespace.ns1.asan.search.paths = /data/vendor/${LIB} 76namespace.ns1.permitted.paths = /vendor/${LIB} 77namespace.ns1.asan.permitted.paths = /data/vendor/${LIB} 78 79# and links it to default namespace 80namespace.ns.links = default 81namespace.ns.link.default.shared_libs = libc.so:libdl.so:libm.so:libstdc++.so 82 83# This defines what libraries are allowed to be loaded from ns1 84namespace.ns1.whitelisted = libsomething.so 85``` 86 87