libnativeloader/public_libraries.cpp - LeafOS-Project/android_art - Gitiles

 /*
  * Copyright (C) 2019 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 #define LOG_TAG "nativeloader"

 #include "public_libraries.h"

 #include <dirent.h>

 #include <algorithm>
 #include <map>
 #include <memory>
 #include <regex>
 #include <string>

 #include <android-base/file.h>
 #include <android-base/logging.h>
 #include <android-base/properties.h>
 #include <android-base/result.h>
 #include <android-base/strings.h>
 #include <log/log.h>

 #if defined(ART_TARGET_ANDROID)
 #include <android/sysprop/VndkProperties.sysprop.h>
 #endif

 #include "utils.h"

 namespace android::nativeloader {

 using android::base::ErrnoError;
 using android::base::Result;
 using internal::ConfigEntry;
 using internal::ParseConfig;
 using internal::ParseApexLibrariesConfig;
 using std::literals::string_literals::operator""s;

 namespace {

 constexpr const char* kDefaultPublicLibrariesFile = "/etc/public.libraries.txt";
 constexpr const char* kExtendedPublicLibrariesFilePrefix = "public.libraries-";
 constexpr const char* kExtendedPublicLibrariesFileSuffix = ".txt";
 constexpr const char* kApexLibrariesConfigFile = "/linkerconfig/apex.libraries.config.txt";
 constexpr const char* kVendorPublicLibrariesFile = "/vendor/etc/public.libraries.txt";
 constexpr const char* kLlndkLibrariesFile = "/apex/com.android.vndk.v{}/etc/llndk.libraries.{}.txt";
 constexpr const char* kVndkLibrariesFile = "/apex/com.android.vndk.v{}/etc/vndksp.libraries.{}.txt";


 // TODO(b/130388701): do we need this?
 std::string root_dir() {
   static const char* android_root_env = getenv("ANDROID_ROOT");
   return android_root_env != nullptr ? android_root_env : "/system";
 }

 bool debuggable() {
   static bool debuggable = android::base::GetBoolProperty("ro.debuggable", false);
   return debuggable;
 }

 std::string vndk_version_str(bool use_product_vndk) {
   if (use_product_vndk) {
     static std::string product_vndk_version = get_vndk_version(true);
     return product_vndk_version;
   } else {
     static std::string vendor_vndk_version = get_vndk_version(false);
     return vendor_vndk_version;
   }
 }

 // For debuggable platform builds use ANDROID_ADDITIONAL_PUBLIC_LIBRARIES environment
 // variable to add libraries to the list. This is intended for platform tests only.
 std::string additional_public_libraries() {
   if (debuggable()) {
     const char* val = getenv("ANDROID_ADDITIONAL_PUBLIC_LIBRARIES");
     return val ? val : "";
   }
   return "";
 }

 // insert vndk version in every {} placeholder
 void InsertVndkVersionStr(std::string* file_name, bool use_product_vndk) {
   CHECK(file_name != nullptr);
   auto version = vndk_version_str(use_product_vndk);
   size_t pos = file_name->find("{}");
   while (pos != std::string::npos) {
     file_name->replace(pos, 2, version);
     pos = file_name->find("{}", pos + version.size());
   }
 }

 const std::function<Result<bool>(const struct ConfigEntry&)> always_true =
     [](const struct ConfigEntry&) -> Result<bool> { return true; };

 Result<std::vector<std::string>> ReadConfig(
     const std::string& configFile,
     const std::function<Result<bool>(const ConfigEntry& /* entry */)>& filter_fn) {
   std::string file_content;
   if (!base::ReadFileToString(configFile, &file_content)) {
     return ErrnoError();
   }
   Result<std::vector<std::string>> result = ParseConfig(file_content, filter_fn);
   if (!result.ok()) {
     return Errorf("Cannot parse {}: {}", configFile, result.error().message());
   }
   return result;
 }

 void ReadExtensionLibraries(const char* dirname, std::vector<std::string>* sonames) {
   std::unique_ptr<DIR, decltype(&closedir)> dir(opendir(dirname), closedir);
   if (dir != nullptr) {
     // Failing to opening the dir is not an error, which can happen in
     // webview_zygote.
     while (struct dirent* ent = readdir(dir.get())) {
       if (ent->d_type != DT_REG && ent->d_type != DT_LNK) {
         continue;
       }
       const std::string filename(ent->d_name);
       std::string_view fn = filename;
       if (android::base::ConsumePrefix(&fn, kExtendedPublicLibrariesFilePrefix) &&
           android::base::ConsumeSuffix(&fn, kExtendedPublicLibrariesFileSuffix)) {
         const std::string company_name(fn);
         const std::string config_file_path = dirname + "/"s + filename;
         LOG_ALWAYS_FATAL_IF(
             company_name.empty(),
             "Error extracting company name from public native library list file path \"%s\"",
             config_file_path.c_str());

         auto ret = ReadConfig(
             config_file_path, [&company_name](const struct ConfigEntry& entry) -> Result<bool> {
               if (android::base::StartsWith(entry.soname, "lib") &&
                   android::base::EndsWith(entry.soname, "." + company_name + ".so")) {
                 return true;
               } else {
                 return Errorf("Library name \"{}\" does not end with the company name {}.",
                               entry.soname, company_name);
               }
             });
         if (ret.ok()) {
           sonames->insert(sonames->end(), ret->begin(), ret->end());
         } else {
           LOG_ALWAYS_FATAL("Error reading public native library list from \"%s\": %s",
                            config_file_path.c_str(), ret.error().message().c_str());
         }
       }
     }
   }
 }

 static std::string InitDefaultPublicLibraries(bool for_preload) {
   std::string config_file = root_dir() + kDefaultPublicLibrariesFile;
   auto sonames =
       ReadConfig(config_file, [&for_preload](const struct ConfigEntry& entry) -> Result<bool> {
         if (for_preload) {
           return !entry.nopreload;
         } else {
           return true;
         }
       });
   if (!sonames.ok()) {
     LOG_ALWAYS_FATAL("Error reading public native library list from \"%s\": %s",
                      config_file.c_str(), sonames.error().message().c_str());
     return "";
   }

   std::string additional_libs = additional_public_libraries();
   if (!additional_libs.empty()) {
     auto vec = base::Split(additional_libs, ":");
     std::copy(vec.begin(), vec.end(), std::back_inserter(*sonames));
   }

   // If this is for preloading libs, don't remove the libs from APEXes.
   if (for_preload) {
     return android::base::Join(*sonames, ':');
   }

   // Remove the public libs provided by apexes because these libs are available
   // from apex namespaces.
   for (const auto& p : apex_public_libraries()) {
     // TODO(b/167578583) remove this `if` block after fixing the bug
     // Skip ART APEX to keep behaviors
     if (p.first == "com_android_art") {
       continue;
     }
     auto public_libs = base::Split(p.second, ":");
     sonames->erase(std::remove_if(sonames->begin(), sonames->end(), [&public_libs](const std::string& v) {
       return std::find(public_libs.begin(), public_libs.end(), v) != public_libs.end();
     }), sonames->end());
   }
   return android::base::Join(*sonames, ':');
 }

 static std::string InitVendorPublicLibraries() {
   // This file is optional, quietly ignore if the file does not exist.
   auto sonames = ReadConfig(kVendorPublicLibrariesFile, always_true);
   if (!sonames.ok()) {
     return "";
   }
   return android::base::Join(*sonames, ':');
 }

 // read /system/etc/public.libraries-<companyname>.txt,
 // /system_ext/etc/public.libraries-<companyname>.txt and
 // /product/etc/public.libraries-<companyname>.txt which contain partner defined
 // system libs that are exposed to apps. The libs in the txt files must be
 // named as lib<name>.<companyname>.so.
 static std::string InitExtendedPublicLibraries() {
   std::vector<std::string> sonames;
   ReadExtensionLibraries("/system/etc", &sonames);
   ReadExtensionLibraries("/system_ext/etc", &sonames);
   ReadExtensionLibraries("/product/etc", &sonames);
   return android::base::Join(sonames, ':');
 }

 static std::string InitLlndkLibrariesVendor() {
   std::string config_file = kLlndkLibrariesFile;
   InsertVndkVersionStr(&config_file, false);
   auto sonames = ReadConfig(config_file, always_true);
   if (!sonames.ok()) {
     LOG_ALWAYS_FATAL("%s: %s", config_file.c_str(), sonames.error().message().c_str());
     return "";
   }
   return android::base::Join(*sonames, ':');
 }

 static std::string InitLlndkLibrariesProduct() {
   if (!is_product_vndk_version_defined()) {
     return "";
   }
   std::string config_file = kLlndkLibrariesFile;
   InsertVndkVersionStr(&config_file, true);
   auto sonames = ReadConfig(config_file, always_true);
   if (!sonames.ok()) {
     LOG_ALWAYS_FATAL("%s: %s", config_file.c_str(), sonames.error().message().c_str());
     return "";
   }
   return android::base::Join(*sonames, ':');
 }

 static std::string InitVndkspLibrariesVendor() {
   std::string config_file = kVndkLibrariesFile;
   InsertVndkVersionStr(&config_file, false);
   auto sonames = ReadConfig(config_file, always_true);
   if (!sonames.ok()) {
     LOG_ALWAYS_FATAL("%s", sonames.error().message().c_str());
     return "";
   }
   return android::base::Join(*sonames, ':');
 }

 static std::string InitVndkspLibrariesProduct() {
   if (!is_product_vndk_version_defined()) {
     return "";
   }
   std::string config_file = kVndkLibrariesFile;
   InsertVndkVersionStr(&config_file, true);
   auto sonames = ReadConfig(config_file, always_true);
   if (!sonames.ok()) {
     LOG_ALWAYS_FATAL("%s", sonames.error().message().c_str());
     return "";
   }
   return android::base::Join(*sonames, ':');
 }

 static std::map<std::string, std::string> InitApexLibraries(const std::string& tag) {
   std::string file_content;
   if (!base::ReadFileToString(kApexLibrariesConfigFile, &file_content)) {
     // config is optional
     return {};
   }
   auto config = ParseApexLibrariesConfig(file_content, tag);
   if (!config.ok()) {
     LOG_ALWAYS_FATAL("%s: %s", kApexLibrariesConfigFile, config.error().message().c_str());
     return {};
   }
   return *config;
 }

 struct ApexLibrariesConfigLine {
   std::string tag;
   std::string apex_namespace;
   std::string library_list;
 };

 const std::regex kApexNamespaceRegex("[0-9a-zA-Z_]+");
 const std::regex kLibraryListRegex("[0-9a-zA-Z.:@+_-]+");

 Result<ApexLibrariesConfigLine> ParseApexLibrariesConfigLine(const std::string& line) {
   std::vector<std::string> tokens = base::Split(line, " ");
   if (tokens.size() != 3) {
     return Errorf("Malformed line \"{}\"", line);
   }
   if (tokens[0] != "jni" && tokens[0] != "public") {
     return Errorf("Invalid tag \"{}\"", line);
   }
   if (!std::regex_match(tokens[1], kApexNamespaceRegex)) {
     return Errorf("Invalid apex_namespace \"{}\"", line);
   }
   if (!std::regex_match(tokens[2], kLibraryListRegex)) {
     return Errorf("Invalid library_list \"{}\"", line);
   }
   return ApexLibrariesConfigLine{std::move(tokens[0]), std::move(tokens[1]), std::move(tokens[2])};
 }

 }  // namespace

 const std::string& preloadable_public_libraries() {
   static std::string list = InitDefaultPublicLibraries(/*for_preload*/ true);
   return list;
 }

 const std::string& default_public_libraries() {
   static std::string list = InitDefaultPublicLibraries(/*for_preload*/ false);
   return list;
 }

 const std::string& vendor_public_libraries() {
   static std::string list = InitVendorPublicLibraries();
   return list;
 }

 const std::string& extended_public_libraries() {
   static std::string list = InitExtendedPublicLibraries();
   return list;
 }

 const std::string& llndk_libraries_product() {
   static std::string list = InitLlndkLibrariesProduct();
   return list;
 }

 const std::string& llndk_libraries_vendor() {
   static std::string list = InitLlndkLibrariesVendor();
   return list;
 }

 const std::string& vndksp_libraries_product() {
   static std::string list = InitVndkspLibrariesProduct();
   return list;
 }

 const std::string& vndksp_libraries_vendor() {
   static std::string list = InitVndkspLibrariesVendor();
   return list;
 }

 const std::string& apex_jni_libraries(const std::string& apex_ns_name) {
   static std::map<std::string, std::string> jni_libraries = InitApexLibraries("jni");
   return jni_libraries[apex_ns_name];
 }

 const std::map<std::string, std::string>& apex_public_libraries() {
   static std::map<std::string, std::string> public_libraries = InitApexLibraries("public");
   return public_libraries;
 }

 bool is_product_vndk_version_defined() {
 #if defined(ART_TARGET_ANDROID)
   return android::sysprop::VndkProperties::product_vndk_version().has_value();
 #else
   return false;
 #endif
 }

 std::string get_vndk_version(bool is_product_vndk) {
 #if defined(ART_TARGET_ANDROID)
   if (is_product_vndk) {
     return android::sysprop::VndkProperties::product_vndk_version().value_or("");
   }
   return android::sysprop::VndkProperties::vendor_vndk_version().value_or("");
 #else
   if (is_product_vndk) {
     return android::base::GetProperty("ro.product.vndk.version", "");
   }
   return android::base::GetProperty("ro.vndk.version", "");
 #endif
 }

 namespace internal {
 // Exported for testing
 Result<std::vector<std::string>> ParseConfig(
     const std::string& file_content,
     const std::function<Result<bool>(const ConfigEntry& /* entry */)>& filter_fn) {
   std::vector<std::string> lines = base::Split(file_content, "\n");

   std::vector<std::string> sonames;
   for (auto& line : lines) {
     auto trimmed_line = base::Trim(line);
     if (trimmed_line[0] == '#' || trimmed_line.empty()) {
       continue;
     }

     std::vector<std::string> tokens = android::base::Split(trimmed_line, " ");
     if (tokens.size() < 1 || tokens.size() > 3) {
       return Errorf("Malformed line \"{}\"", line);
     }
     struct ConfigEntry entry = {.soname = "", .nopreload = false, .bitness = ALL};
     size_t i = tokens.size();
     while (i-- > 0) {
       if (tokens[i] == "nopreload") {
         entry.nopreload = true;
       } else if (tokens[i] == "32" || tokens[i] == "64") {
         if (entry.bitness != ALL) {
           return Errorf("Malformed line \"{}\": bitness can be specified only once", line);
         }
         entry.bitness = tokens[i] == "32" ? ONLY_32 : ONLY_64;
       } else {
         if (i != 0) {
           return Errorf("Malformed line \"{}\"", line);
         }
         entry.soname = tokens[i];
       }
     }

     // skip 32-bit lib on 64-bit process and vice versa
 #if defined(__LP64__)
     if (entry.bitness == ONLY_32) continue;
 #else
     if (entry.bitness == ONLY_64) continue;
 #endif

     Result<bool> ret = filter_fn(entry);
     if (!ret.ok()) {
       return ret.error();
     }
     if (*ret) {
       // filter_fn has returned true.
       sonames.push_back(entry.soname);
     }
   }
   return sonames;
 }

 // Parses apex.libraries.config.txt file generated by linkerconfig which looks like
 //   system/linkerconfig/testdata/golden_output/stages/apex.libraries.config.txt
 // and returns mapping of <apex namespace> to <library list> which matches <tag>.
 //
 // The file is line-based and each line consists of "<tag> <apex namespace> <library list>".
 //
 // <tag> explains what <library list> is. (e.g "jni", "public")
 // <library list> is colon-separated list of library names. (e.g "libfoo.so:libbar.so")
 //
 // 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>.
 // Public libraries are the libs listed in /system/etc/public.libraries.txt.
 Result<std::map<std::string, std::string>> ParseApexLibrariesConfig(const std::string& file_content, const std::string& tag) {
   std::map<std::string, std::string> entries;
   std::vector<std::string> lines = base::Split(file_content, "\n");
   for (auto& line : lines) {
     auto trimmed_line = base::Trim(line);
     if (trimmed_line[0] == '#' || trimmed_line.empty()) {
       continue;
     }
     auto config_line = ParseApexLibrariesConfigLine(trimmed_line);
     if (!config_line.ok()) {
       return config_line.error();
     }
     if (config_line->tag != tag) {
       continue;
     }
     entries[config_line->apex_namespace] = config_line->library_list;
   }

   // TODO(b/167578583) remove this `if` block after fixing the bug
   if (tag == "public") {
     std::string additional_libs = additional_public_libraries();
     if (!additional_libs.empty()) {
       entries["com_android_art"] += ':' + additional_libs;
     }
   }
   return entries;
 }

 }  // namespace internal

 }  // namespace android::nativeloader
	/*
	* Copyright (C) 2019 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#define LOG_TAG "nativeloader"

	#include "public_libraries.h"

	#include <dirent.h>

	#include <algorithm>
	#include <map>
	#include <memory>
	#include <regex>
	#include <string>

	#include <android-base/file.h>
	#include <android-base/logging.h>
	#include <android-base/properties.h>
	#include <android-base/result.h>
	#include <android-base/strings.h>
	#include <log/log.h>

	#if defined(ART_TARGET_ANDROID)
	#include <android/sysprop/VndkProperties.sysprop.h>
	#endif

	#include "utils.h"

	namespace android::nativeloader {

	using android::base::ErrnoError;
	using android::base::Result;
	using internal::ConfigEntry;
	using internal::ParseConfig;
	using internal::ParseApexLibrariesConfig;
	using std::literals::string_literals::operator""s;

	namespace {

	constexpr const char* kDefaultPublicLibrariesFile = "/etc/public.libraries.txt";
	constexpr const char* kExtendedPublicLibrariesFilePrefix = "public.libraries-";
	constexpr const char* kExtendedPublicLibrariesFileSuffix = ".txt";
	constexpr const char* kApexLibrariesConfigFile = "/linkerconfig/apex.libraries.config.txt";
	constexpr const char* kVendorPublicLibrariesFile = "/vendor/etc/public.libraries.txt";
	constexpr const char* kLlndkLibrariesFile = "/apex/com.android.vndk.v{}/etc/llndk.libraries.{}.txt";
	constexpr const char* kVndkLibrariesFile = "/apex/com.android.vndk.v{}/etc/vndksp.libraries.{}.txt";


	// TODO(b/130388701): do we need this?
	std::string root_dir() {
	static const char* android_root_env = getenv("ANDROID_ROOT");
	return android_root_env != nullptr ? android_root_env : "/system";
	}

	bool debuggable() {
	static bool debuggable = android::base::GetBoolProperty("ro.debuggable", false);
	return debuggable;
	}

	std::string vndk_version_str(bool use_product_vndk) {
	if (use_product_vndk) {
	static std::string product_vndk_version = get_vndk_version(true);
	return product_vndk_version;
	} else {
	static std::string vendor_vndk_version = get_vndk_version(false);
	return vendor_vndk_version;
	}
	}

	// For debuggable platform builds use ANDROID_ADDITIONAL_PUBLIC_LIBRARIES environment
	// variable to add libraries to the list. This is intended for platform tests only.
	std::string additional_public_libraries() {
	if (debuggable()) {
	const char* val = getenv("ANDROID_ADDITIONAL_PUBLIC_LIBRARIES");
	return val ? val : "";
	}
	return "";
	}

	// insert vndk version in every {} placeholder
	void InsertVndkVersionStr(std::string* file_name, bool use_product_vndk) {
	CHECK(file_name != nullptr);
	auto version = vndk_version_str(use_product_vndk);
	size_t pos = file_name->find("{}");
	while (pos != std::string::npos) {
	file_name->replace(pos, 2, version);
	pos = file_name->find("{}", pos + version.size());
	}
	}

	const std::function<Result<bool>(const struct ConfigEntry&)> always_true =
	[](const struct ConfigEntry&) -> Result<bool> { return true; };

	Result<std::vector<std::string>> ReadConfig(
	const std::string& configFile,
	const std::function<Result<bool>(const ConfigEntry& /* entry */)>& filter_fn) {
	std::string file_content;
	if (!base::ReadFileToString(configFile, &file_content)) {
	return ErrnoError();
	}
	Result<std::vector<std::string>> result = ParseConfig(file_content, filter_fn);
	if (!result.ok()) {
	return Errorf("Cannot parse {}: {}", configFile, result.error().message());
	}
	return result;
	}

	void ReadExtensionLibraries(const char* dirname, std::vector<std::string>* sonames) {
	std::unique_ptr<DIR, decltype(&closedir)> dir(opendir(dirname), closedir);
	if (dir != nullptr) {
	// Failing to opening the dir is not an error, which can happen in
	// webview_zygote.
	while (struct dirent* ent = readdir(dir.get())) {
	if (ent->d_type != DT_REG && ent->d_type != DT_LNK) {
	continue;
	}
	const std::string filename(ent->d_name);
	std::string_view fn = filename;
	if (android::base::ConsumePrefix(&fn, kExtendedPublicLibrariesFilePrefix) &&
	android::base::ConsumeSuffix(&fn, kExtendedPublicLibrariesFileSuffix)) {
	const std::string company_name(fn);
	const std::string config_file_path = dirname + "/"s + filename;
	LOG_ALWAYS_FATAL_IF(
	company_name.empty(),
	"Error extracting company name from public native library list file path \"%s\"",
	config_file_path.c_str());

	auto ret = ReadConfig(
	config_file_path, [&company_name](const struct ConfigEntry& entry) -> Result<bool> {
	if (android::base::StartsWith(entry.soname, "lib") &&
	android::base::EndsWith(entry.soname, "." + company_name + ".so")) {
	return true;
	} else {
	return Errorf("Library name \"{}\" does not end with the company name {}.",
	entry.soname, company_name);
	}
	});
	if (ret.ok()) {
	sonames->insert(sonames->end(), ret->begin(), ret->end());
	} else {
	LOG_ALWAYS_FATAL("Error reading public native library list from \"%s\": %s",
	config_file_path.c_str(), ret.error().message().c_str());
	}
	}
	}
	}
	}

	static std::string InitDefaultPublicLibraries(bool for_preload) {
	std::string config_file = root_dir() + kDefaultPublicLibrariesFile;
	auto sonames =
	ReadConfig(config_file, [&for_preload](const struct ConfigEntry& entry) -> Result<bool> {
	if (for_preload) {
	return !entry.nopreload;
	} else {
	return true;
	}
	});
	if (!sonames.ok()) {
	LOG_ALWAYS_FATAL("Error reading public native library list from \"%s\": %s",
	config_file.c_str(), sonames.error().message().c_str());
	return "";
	}

	std::string additional_libs = additional_public_libraries();
	if (!additional_libs.empty()) {
	auto vec = base::Split(additional_libs, ":");
	std::copy(vec.begin(), vec.end(), std::back_inserter(*sonames));
	}

	// If this is for preloading libs, don't remove the libs from APEXes.
	if (for_preload) {
	return android::base::Join(*sonames, ':');
	}

	// Remove the public libs provided by apexes because these libs are available
	// from apex namespaces.
	for (const auto& p : apex_public_libraries()) {
	// TODO(b/167578583) remove this `if` block after fixing the bug
	// Skip ART APEX to keep behaviors
	if (p.first == "com_android_art") {
	continue;
	}
	auto public_libs = base::Split(p.second, ":");
	sonames->erase(std::remove_if(sonames->begin(), sonames->end(), [&public_libs](const std::string& v) {
	return std::find(public_libs.begin(), public_libs.end(), v) != public_libs.end();
	}), sonames->end());
	}
	return android::base::Join(*sonames, ':');
	}

	static std::string InitVendorPublicLibraries() {
	// This file is optional, quietly ignore if the file does not exist.
	auto sonames = ReadConfig(kVendorPublicLibrariesFile, always_true);
	if (!sonames.ok()) {
	return "";
	}
	return android::base::Join(*sonames, ':');
	}

	// read /system/etc/public.libraries-<companyname>.txt,
	// /system_ext/etc/public.libraries-<companyname>.txt and
	// /product/etc/public.libraries-<companyname>.txt which contain partner defined
	// system libs that are exposed to apps. The libs in the txt files must be
	// named as lib<name>.<companyname>.so.
	static std::string InitExtendedPublicLibraries() {
	std::vector<std::string> sonames;
	ReadExtensionLibraries("/system/etc", &sonames);
	ReadExtensionLibraries("/system_ext/etc", &sonames);
	ReadExtensionLibraries("/product/etc", &sonames);
	return android::base::Join(sonames, ':');
	}

	static std::string InitLlndkLibrariesVendor() {
	std::string config_file = kLlndkLibrariesFile;
	InsertVndkVersionStr(&config_file, false);
	auto sonames = ReadConfig(config_file, always_true);
	if (!sonames.ok()) {
	LOG_ALWAYS_FATAL("%s: %s", config_file.c_str(), sonames.error().message().c_str());
	return "";
	}
	return android::base::Join(*sonames, ':');
	}

	static std::string InitLlndkLibrariesProduct() {
	if (!is_product_vndk_version_defined()) {
	return "";
	}
	std::string config_file = kLlndkLibrariesFile;
	InsertVndkVersionStr(&config_file, true);
	auto sonames = ReadConfig(config_file, always_true);
	if (!sonames.ok()) {
	LOG_ALWAYS_FATAL("%s: %s", config_file.c_str(), sonames.error().message().c_str());
	return "";
	}
	return android::base::Join(*sonames, ':');
	}

	static std::string InitVndkspLibrariesVendor() {
	std::string config_file = kVndkLibrariesFile;
	InsertVndkVersionStr(&config_file, false);
	auto sonames = ReadConfig(config_file, always_true);
	if (!sonames.ok()) {
	LOG_ALWAYS_FATAL("%s", sonames.error().message().c_str());
	return "";
	}
	return android::base::Join(*sonames, ':');
	}

	static std::string InitVndkspLibrariesProduct() {
	if (!is_product_vndk_version_defined()) {
	return "";
	}
	std::string config_file = kVndkLibrariesFile;
	InsertVndkVersionStr(&config_file, true);
	auto sonames = ReadConfig(config_file, always_true);
	if (!sonames.ok()) {
	LOG_ALWAYS_FATAL("%s", sonames.error().message().c_str());
	return "";
	}
	return android::base::Join(*sonames, ':');
	}

	static std::map<std::string, std::string> InitApexLibraries(const std::string& tag) {
	std::string file_content;
	if (!base::ReadFileToString(kApexLibrariesConfigFile, &file_content)) {
	// config is optional
	return {};
	}
	auto config = ParseApexLibrariesConfig(file_content, tag);
	if (!config.ok()) {
	LOG_ALWAYS_FATAL("%s: %s", kApexLibrariesConfigFile, config.error().message().c_str());
	return {};
	}
	return *config;
	}

	struct ApexLibrariesConfigLine {
	std::string tag;
	std::string apex_namespace;
	std::string library_list;
	};

	const std::regex kApexNamespaceRegex("[0-9a-zA-Z_]+");
	const std::regex kLibraryListRegex("[0-9a-zA-Z.:@+_-]+");

	Result<ApexLibrariesConfigLine> ParseApexLibrariesConfigLine(const std::string& line) {
	std::vector<std::string> tokens = base::Split(line, " ");
	if (tokens.size() != 3) {
	return Errorf("Malformed line \"{}\"", line);
	}
	if (tokens[0] != "jni" && tokens[0] != "public") {
	return Errorf("Invalid tag \"{}\"", line);
	}
	if (!std::regex_match(tokens[1], kApexNamespaceRegex)) {
	return Errorf("Invalid apex_namespace \"{}\"", line);
	}
	if (!std::regex_match(tokens[2], kLibraryListRegex)) {
	return Errorf("Invalid library_list \"{}\"", line);
	}
	return ApexLibrariesConfigLine{std::move(tokens[0]), std::move(tokens[1]), std::move(tokens[2])};
	}

	} // namespace

	const std::string& preloadable_public_libraries() {
	static std::string list = InitDefaultPublicLibraries(/for_preload/ true);
	return list;
	}

	const std::string& default_public_libraries() {
	static std::string list = InitDefaultPublicLibraries(/for_preload/ false);
	return list;
	}

	const std::string& vendor_public_libraries() {
	static std::string list = InitVendorPublicLibraries();
	return list;
	}

	const std::string& extended_public_libraries() {
	static std::string list = InitExtendedPublicLibraries();
	return list;
	}

	const std::string& llndk_libraries_product() {
	static std::string list = InitLlndkLibrariesProduct();
	return list;
	}

	const std::string& llndk_libraries_vendor() {
	static std::string list = InitLlndkLibrariesVendor();
	return list;
	}

	const std::string& vndksp_libraries_product() {
	static std::string list = InitVndkspLibrariesProduct();
	return list;
	}

	const std::string& vndksp_libraries_vendor() {
	static std::string list = InitVndkspLibrariesVendor();
	return list;
	}

	const std::string& apex_jni_libraries(const std::string& apex_ns_name) {
	static std::map<std::string, std::string> jni_libraries = InitApexLibraries("jni");
	return jni_libraries[apex_ns_name];
	}

	const std::map<std::string, std::string>& apex_public_libraries() {
	static std::map<std::string, std::string> public_libraries = InitApexLibraries("public");
	return public_libraries;
	}

	bool is_product_vndk_version_defined() {
	#if defined(ART_TARGET_ANDROID)
	return android::sysprop::VndkProperties::product_vndk_version().has_value();
	#else
	return false;
	#endif
	}

	std::string get_vndk_version(bool is_product_vndk) {
	#if defined(ART_TARGET_ANDROID)
	if (is_product_vndk) {
	return android::sysprop::VndkProperties::product_vndk_version().value_or("");
	}
	return android::sysprop::VndkProperties::vendor_vndk_version().value_or("");
	#else
	if (is_product_vndk) {
	return android::base::GetProperty("ro.product.vndk.version", "");
	}
	return android::base::GetProperty("ro.vndk.version", "");
	#endif
	}

	namespace internal {
	// Exported for testing
	Result<std::vector<std::string>> ParseConfig(
	const std::string& file_content,
	const std::function<Result<bool>(const ConfigEntry& /* entry */)>& filter_fn) {
	std::vector<std::string> lines = base::Split(file_content, "\n");

	std::vector<std::string> sonames;
	for (auto& line : lines) {
	auto trimmed_line = base::Trim(line);
	if (trimmed_line[0] == '#' \|\| trimmed_line.empty()) {
	continue;
	}

	std::vector<std::string> tokens = android::base::Split(trimmed_line, " ");
	if (tokens.size() < 1 \|\| tokens.size() > 3) {
	return Errorf("Malformed line \"{}\"", line);
	}
	struct ConfigEntry entry = {.soname = "", .nopreload = false, .bitness = ALL};
	size_t i = tokens.size();
	while (i-- > 0) {
	if (tokens[i] == "nopreload") {
	entry.nopreload = true;
	} else if (tokens[i] == "32" \|\| tokens[i] == "64") {
	if (entry.bitness != ALL) {
	return Errorf("Malformed line \"{}\": bitness can be specified only once", line);
	}
	entry.bitness = tokens[i] == "32" ? ONLY_32 : ONLY_64;
	} else {
	if (i != 0) {
	return Errorf("Malformed line \"{}\"", line);
	}
	entry.soname = tokens[i];
	}
	}

	// skip 32-bit lib on 64-bit process and vice versa
	#if defined(__LP64__)
	if (entry.bitness == ONLY_32) continue;
	#else
	if (entry.bitness == ONLY_64) continue;
	#endif

	Result<bool> ret = filter_fn(entry);
	if (!ret.ok()) {
	return ret.error();
	}
	if (*ret) {
	// filter_fn has returned true.
	sonames.push_back(entry.soname);
	}
	}
	return sonames;
	}

	// Parses apex.libraries.config.txt file generated by linkerconfig which looks like
	// system/linkerconfig/testdata/golden_output/stages/apex.libraries.config.txt
	// and returns mapping of <apex namespace> to <library list> which matches <tag>.
	//
	// The file is line-based and each line consists of "<tag> <apex namespace> <library list>".
	//
	// <tag> explains what <library list> is. (e.g "jni", "public")
	// <library list> is colon-separated list of library names. (e.g "libfoo.so:libbar.so")
	//
	// 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>.
	// Public libraries are the libs listed in /system/etc/public.libraries.txt.
	Result<std::map<std::string, std::string>> ParseApexLibrariesConfig(const std::string& file_content, const std::string& tag) {
	std::map<std::string, std::string> entries;
	std::vector<std::string> lines = base::Split(file_content, "\n");
	for (auto& line : lines) {
	auto trimmed_line = base::Trim(line);
	if (trimmed_line[0] == '#' \|\| trimmed_line.empty()) {
	continue;
	}
	auto config_line = ParseApexLibrariesConfigLine(trimmed_line);
	if (!config_line.ok()) {
	return config_line.error();
	}
	if (config_line->tag != tag) {
	continue;
	}
	entries[config_line->apex_namespace] = config_line->library_list;
	}

	// TODO(b/167578583) remove this `if` block after fixing the bug
	if (tag == "public") {
	std::string additional_libs = additional_public_libraries();
	if (!additional_libs.empty()) {
	entries["com_android_art"] += ':' + additional_libs;
	}
	}
	return entries;
	}

	} // namespace internal

	} // namespace android::nativeloader