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* 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
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* See the License for the specific language governing permissions and
* limitations under the License.
#include "library_namespaces.h"
#include <dirent.h>
#include <dlfcn.h>
#include <regex>
#include <string>
#include <vector>
#include <android-base/file.h>
#include <android-base/logging.h>
#include <android-base/macros.h>
#include <android-base/result.h>
#include <android-base/strings.h>
#include <nativehelper/scoped_utf_chars.h>
#include "nativeloader/dlext_namespaces.h"
#include "public_libraries.h"
#include "utils.h"
namespace android::nativeloader {
namespace {
constexpr const char* kApexPath = "/apex/";
// The device may be configured to have the vendor libraries loaded to a separate namespace.
// For historical reasons this namespace was named sphal but effectively it is intended
// to use to load vendor libraries to separate namespace with controlled interface between
// vendor and system namespaces.
constexpr const char* kVendorNamespaceName = "sphal";
// Similar to sphal namespace, product namespace provides some product libraries.
constexpr const char* kProductNamespaceName = "product";
// vndk namespace for unbundled vendor apps
constexpr const char* kVndkNamespaceName = "vndk";
// vndk_product namespace for unbundled product apps
constexpr const char* kVndkProductNamespaceName = "vndk_product";
// classloader-namespace is a linker namespace that is created for the loaded
// app. To be specific, it is created for the app classloader. When
// System.load() is called from a Java class that is loaded from the
// classloader, the classloader-namespace namespace associated with that
// classloader is selected for dlopen. The namespace is configured so that its
// search path is set to the app-local JNI directory and it is linked to the
// system namespace with the names of libs listed in the public.libraries.txt.
// This way an app can only load its own JNI libraries along with the public libs.
constexpr const char* kClassloaderNamespaceName = "classloader-namespace";
// Same thing for vendor APKs.
constexpr const char* kVendorClassloaderNamespaceName = "vendor-classloader-namespace";
// If the namespace is shared then add this suffix to form
// "classloader-namespace-shared" or "vendor-classloader-namespace-shared",
// respectively. A shared namespace (cf. ANDROID_NAMESPACE_TYPE_SHARED) has
// inherited all the libraries of the parent classloader namespace, or the
// system namespace for the main app classloader. It is used to give full
// access to the platform libraries for apps bundled in the system image,
// including their later updates installed in /data.
constexpr const char* kSharedNamespaceSuffix = "-shared";
// (http://b/27588281) This is a workaround for apps using custom classloaders and calling
// System.load() with an absolute path which is outside of the classloader library search path.
// This list includes all directories app is allowed to access this way.
constexpr const char* kAlwaysPermittedDirectories = "/data:/mnt/expand";
constexpr const char* kVendorLibPath = "/vendor/" LIB;
constexpr const char* kProductLibPath = "/product/" LIB ":/system/product/" LIB;
const std::regex kVendorDexPathRegex("(^|:)/vendor/");
const std::regex kProductDexPathRegex("(^|:)(/system)?/product/");
// Define origin of APK if it is from vendor partition or product partition
using ApkOrigin = enum {
jobject GetParentClassLoader(JNIEnv* env, jobject class_loader) {
jclass class_loader_class = env->FindClass("java/lang/ClassLoader");
jmethodID get_parent =
env->GetMethodID(class_loader_class, "getParent", "()Ljava/lang/ClassLoader;");
return env->CallObjectMethod(class_loader, get_parent);
ApkOrigin GetApkOriginFromDexPath(const std::string& dex_path) {
ApkOrigin apk_origin = APK_ORIGIN_DEFAULT;
if (std::regex_search(dex_path, kVendorDexPathRegex)) {
apk_origin = APK_ORIGIN_VENDOR;
if (std::regex_search(dex_path, kProductDexPathRegex)) {
"Dex path contains both vendor and product partition : %s",
apk_origin = APK_ORIGIN_PRODUCT;
return apk_origin;
} // namespace
void LibraryNamespaces::Initialize() {
// Once public namespace is initialized there is no
// point in running this code - it will have no effect
// on the current list of public libraries.
if (initialized_) {
// Load the preloadable public libraries. Since libnativeloader is in the
// com_android_art namespace, use OpenSystemLibrary rather than dlopen to
// ensure the libraries are loaded in the system namespace.
// TODO(dimitry): this is a bit misleading since we do not know
// if the vendor public library is going to be opened from /vendor/lib
// we might as well end up loading them from /system/lib or /product/lib
// For now we rely on CTS test to catch things like this but
// it should probably be addressed in the future.
for (const std::string& soname : android::base::Split(preloadable_public_libraries(), ":")) {
void* handle = OpenSystemLibrary(soname.c_str(), RTLD_NOW | RTLD_NODELETE);
LOG_ALWAYS_FATAL_IF(handle == nullptr,
"Error preloading public library %s: %s", soname.c_str(), dlerror());
// "ALL" is a magic name that allows all public libraries even when the
// target SDK is > 30. Currently this is used for (Java) shared libraries
// which don't use <uses-native-library>
// TODO(b/142191088) remove this hack
static constexpr const char LIBRARY_ALL[] = "ALL";
// Returns the colon-separated list of library names by filtering uses_libraries from
// public_libraries. The returned names will actually be available to the app. If the app is pre-S
// (<= 30), the filtering is not done; the entire public_libraries are provided.
static const std::string filter_public_libraries(
uint32_t target_sdk_version, const std::vector<std::string>& uses_libraries,
const std::string& public_libraries) {
// Apps targeting Android 11 or earlier gets all public libraries
if (target_sdk_version <= 30) {
return public_libraries;
if (std::find(uses_libraries.begin(), uses_libraries.end(), LIBRARY_ALL) !=
uses_libraries.end()) {
return public_libraries;
std::vector<std::string> filtered;
std::vector<std::string> orig = android::base::Split(public_libraries, ":");
for (const auto& lib : uses_libraries) {
if (std::find(orig.begin(), orig.end(), lib) != orig.end()) {
return android::base::Join(filtered, ":");
Result<NativeLoaderNamespace*> LibraryNamespaces::Create(JNIEnv* env, uint32_t target_sdk_version,
jobject class_loader, bool is_shared,
jstring dex_path_j,
jstring java_library_path,
jstring java_permitted_path,
jstring uses_library_list) {
std::string library_path; // empty string by default.
std::string dex_path;
if (java_library_path != nullptr) {
ScopedUtfChars library_path_utf_chars(env, java_library_path);
library_path = library_path_utf_chars.c_str();
if (dex_path_j != nullptr) {
ScopedUtfChars dex_path_chars(env, dex_path_j);
dex_path = dex_path_chars.c_str();
std::vector<std::string> uses_libraries;
if (uses_library_list != nullptr) {
ScopedUtfChars names(env, uses_library_list);
uses_libraries = android::base::Split(names.c_str(), ":");
} else {
// uses_library_list could be nullptr when System.loadLibrary is called from a
// custom classloader. In that case, we don't know the list of public
// libraries because we don't know which apk the classloader is for. Only
// choices we can have are 1) allowing all public libs (as before), or 2)
// not allowing all but NDK libs. Here we take #1 because #2 would surprise
// developers unnecessarily.
// TODO(b/142191088) finalize the policy here. We could either 1) allow all
// public libs, 2) disallow any lib, or 3) use the libs that were granted to
// the first (i.e. app main) classloader.
ApkOrigin apk_origin = GetApkOriginFromDexPath(dex_path);
// (http://b/27588281) This is a workaround for apps using custom
// classloaders and calling System.load() with an absolute path which
// is outside of the classloader library search path.
// This part effectively allows such a classloader to access anything
// under /data and /mnt/expand
std::string permitted_path = kAlwaysPermittedDirectories;
if (java_permitted_path != nullptr) {
ScopedUtfChars path(env, java_permitted_path);
if (path.c_str() != nullptr && path.size() > 0) {
permitted_path = permitted_path + ":" + path.c_str();
LOG_ALWAYS_FATAL_IF(FindNamespaceByClassLoader(env, class_loader) != nullptr,
"There is already a namespace associated with this classloader");
std::string system_exposed_libraries = default_public_libraries();
std::string namespace_name = kClassloaderNamespaceName;
ApkOrigin unbundled_app_origin = APK_ORIGIN_DEFAULT;
if ((apk_origin == APK_ORIGIN_VENDOR ||
(apk_origin == APK_ORIGIN_PRODUCT &&
is_product_vndk_version_defined())) &&
!is_shared) {
unbundled_app_origin = apk_origin;
// For vendor / product apks, give access to the vendor / product lib even though
// they are treated as unbundled; the libs and apks are still bundled
// together in the vendor / product partition.
const char* origin_partition;
const char* origin_lib_path;
const char* llndk_libraries;
switch (apk_origin) {
origin_partition = "vendor";
origin_lib_path = kVendorLibPath;
llndk_libraries = llndk_libraries_vendor().c_str();
origin_partition = "product";
origin_lib_path = kProductLibPath;
llndk_libraries = llndk_libraries_product().c_str();
origin_partition = "unknown";
origin_lib_path = "";
llndk_libraries = "";
library_path = library_path + ":" + origin_lib_path;
permitted_path = permitted_path + ":" + origin_lib_path;
// Also give access to LLNDK libraries since they are available to vendor or product
system_exposed_libraries = system_exposed_libraries + ":" + llndk_libraries;
// Different name is useful for debugging
namespace_name = kVendorClassloaderNamespaceName;
ALOGD("classloader namespace configured for unbundled %s apk. library_path=%s",
origin_partition, library_path.c_str());
} else {
auto libs = filter_public_libraries(target_sdk_version, uses_libraries,
// extended public libraries are NOT available to vendor apks, otherwise it
// would be system->vendor violation.
if (!libs.empty()) {
system_exposed_libraries = system_exposed_libraries + ':' + libs;
if (is_shared) {
// Show in the name that the namespace was created as shared, for debugging
// purposes.
namespace_name = namespace_name + kSharedNamespaceSuffix;
// Create the app namespace
NativeLoaderNamespace* parent_ns = FindParentNamespaceByClassLoader(env, class_loader);
// Heuristic: the first classloader with non-empty library_path is assumed to
// be the main classloader for app
// TODO(b/139178525) remove this heuristic by determining this in LoadedApk (or its
// friends) and then passing it down to here.
bool is_main_classloader = app_main_namespace_ == nullptr && !library_path.empty();
// Policy: the namespace for the main classloader is also used as the
// anonymous namespace.
bool also_used_as_anonymous = is_main_classloader;
// Note: this function is executed with g_namespaces_mutex held, thus no
// racing here.
auto app_ns = NativeLoaderNamespace::Create(
namespace_name, library_path, permitted_path, parent_ns, is_shared,
target_sdk_version < 24 /* is_exempt_list_enabled */, also_used_as_anonymous);
if (!app_ns.ok()) {
return app_ns.error();
// ... and link to other namespaces to allow access to some public libraries
bool is_bridged = app_ns->IsBridged();
auto system_ns = NativeLoaderNamespace::GetSystemNamespace(is_bridged);
if (!system_ns.ok()) {
return system_ns.error();
auto linked = app_ns->Link(&system_ns.value(), system_exposed_libraries);
if (!linked.ok()) {
return linked.error();
for (const auto&[apex_ns_name, public_libs] : apex_public_libraries()) {
auto ns = NativeLoaderNamespace::GetExportedNamespace(apex_ns_name, is_bridged);
// Even if APEX namespace is visible, it may not be available to bridged.
if (ns.ok()) {
linked = app_ns->Link(&ns.value(), public_libs);
if (!linked.ok()) {
return linked.error();
// Give access to VNDK-SP libraries from the 'vndk' namespace for unbundled vendor apps.
if (unbundled_app_origin == APK_ORIGIN_VENDOR && !vndksp_libraries_vendor().empty()) {
auto vndk_ns = NativeLoaderNamespace::GetExportedNamespace(kVndkNamespaceName, is_bridged);
if (vndk_ns.ok()) {
linked = app_ns->Link(&vndk_ns.value(), vndksp_libraries_vendor());
if (!linked.ok()) {
return linked.error();
// Give access to VNDK-SP libraries from the 'vndk_product' namespace for unbundled product apps.
if (unbundled_app_origin == APK_ORIGIN_PRODUCT && !vndksp_libraries_product().empty()) {
auto vndk_ns = NativeLoaderNamespace::GetExportedNamespace(kVndkProductNamespaceName, is_bridged);
if (vndk_ns.ok()) {
linked = app_ns->Link(&vndk_ns.value(), vndksp_libraries_product());
if (!linked.ok()) {
return linked.error();
for (const std::string& each_jar_path : android::base::Split(dex_path, ":")) {
auto apex_ns_name = FindApexNamespaceName(each_jar_path);
if (apex_ns_name.ok()) {
const auto& jni_libs = apex_jni_libraries(*apex_ns_name);
if (jni_libs != "") {
auto apex_ns = NativeLoaderNamespace::GetExportedNamespace(*apex_ns_name, is_bridged);
if (apex_ns.ok()) {
linked = app_ns->Link(&apex_ns.value(), jni_libs);
if (!linked.ok()) {
return linked.error();
auto vendor_libs = filter_public_libraries(target_sdk_version, uses_libraries,
if (!vendor_libs.empty()) {
auto vendor_ns = NativeLoaderNamespace::GetExportedNamespace(kVendorNamespaceName, is_bridged);
// when vendor_ns is not configured, link to the system namespace
auto target_ns = vendor_ns.ok() ? vendor_ns : system_ns;
if (target_ns.ok()) {
linked = app_ns->Link(&target_ns.value(), vendor_libs);
if (!linked.ok()) {
return linked.error();
auto product_libs = filter_public_libraries(target_sdk_version, uses_libraries,
if (!product_libs.empty()) {
auto target_ns = system_ns;
if (is_product_vndk_version_defined()) {
// If ro.product.vndk.version is defined, product namespace provides the product libraries.
target_ns = NativeLoaderNamespace::GetExportedNamespace(kProductNamespaceName, is_bridged);
if (target_ns.ok()) {
linked = app_ns->Link(&target_ns.value(), product_libs);
if (!linked.ok()) {
return linked.error();
} else {
// The linkerconfig must have a problem on defining the product namespace in the system
// section. Skip linking product namespace. This will not affect most of the apps. Only the
// apps that requires the product public libraries will fail.
ALOGW("Namespace for product libs not found: %s", target_ns.error().message().c_str());
auto& emplaced = namespaces_.emplace_back(
std::make_pair(env->NewWeakGlobalRef(class_loader), *app_ns));
if (is_main_classloader) {
app_main_namespace_ = &emplaced.second;
return &emplaced.second;
NativeLoaderNamespace* LibraryNamespaces::FindNamespaceByClassLoader(JNIEnv* env,
jobject class_loader) {
auto it = std::find_if(namespaces_.begin(), namespaces_.end(),
[&](const std::pair<jweak, NativeLoaderNamespace>& value) {
return env->IsSameObject(value.first, class_loader);
if (it != namespaces_.end()) {
return &it->second;
return nullptr;
NativeLoaderNamespace* LibraryNamespaces::FindParentNamespaceByClassLoader(JNIEnv* env,
jobject class_loader) {
jobject parent_class_loader = GetParentClassLoader(env, class_loader);
while (parent_class_loader != nullptr) {
NativeLoaderNamespace* ns;
if ((ns = FindNamespaceByClassLoader(env, parent_class_loader)) != nullptr) {
return ns;
parent_class_loader = GetParentClassLoader(env, parent_class_loader);
return nullptr;
base::Result<std::string> FindApexNamespaceName(const std::string& location) {
// Lots of implicit assumptions here: we expect `location` to be of the form:
// /apex/modulename/...
// And we extract from it 'modulename', and then apply mangling rule to get namespace name for it.
if (android::base::StartsWith(location, kApexPath)) {
size_t start_index = strlen(kApexPath);
size_t slash_index = location.find_first_of('/', start_index);
LOG_ALWAYS_FATAL_IF((slash_index == std::string::npos),
"Error finding namespace of apex: no slash in path %s", location.c_str());
std::string name = location.substr(start_index, slash_index - start_index);
std::replace(name.begin(), name.end(), '.', '_');
return name;
return base::Error();
} // namespace android::nativeloader
#endif // defined(ART_TARGET_ANDROID)