aosp12/art/libnativeloader/native_loader.cpp

401 lines
15 KiB
C++

/*
* Copyright (C) 2015 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 "nativeloader/native_loader.h"
#include <dlfcn.h>
#include <sys/types.h>
#include <algorithm>
#include <memory>
#include <mutex>
#include <string>
#include <vector>
#include <android-base/file.h>
#include <android-base/macros.h>
#include <android-base/strings.h>
#include <android-base/thread_annotations.h>
#include <nativebridge/native_bridge.h>
#include <nativehelper/scoped_utf_chars.h>
#ifdef ART_TARGET_ANDROID
#include <log/log.h>
#include "library_namespaces.h"
#include "nativeloader/dlext_namespaces.h"
#endif
namespace android {
namespace {
#if defined(ART_TARGET_ANDROID)
// NATIVELOADER_DEFAULT_NAMESPACE_LIBS is an environment variable that can be
// used to list extra libraries (separated by ":") that libnativeloader will
// load from the default namespace. The libraries must be listed without paths,
// and then LD_LIBRARY_PATH is typically set to the directories to load them
// from. The libraries will be available in all classloader namespaces, and also
// in the fallback namespace used when no classloader is given.
//
// kNativeloaderExtraLibs is the name of that fallback namespace.
//
// NATIVELOADER_DEFAULT_NAMESPACE_LIBS is intended to be used for testing only,
// and in particular in the ART run tests that are executed through dalvikvm in
// the APEX. In that case the default namespace links to the ART namespace
// (com_android_art) for all libraries, which means this can be used to load
// test libraries that depend on ART internal libraries.
constexpr const char* kNativeloaderExtraLibs = "nativeloader-extra-libs";
using android::nativeloader::LibraryNamespaces;
std::mutex g_namespaces_mutex;
LibraryNamespaces* g_namespaces = new LibraryNamespaces;
NativeLoaderNamespace* g_nativeloader_extra_libs_namespace = nullptr;
android_namespace_t* FindExportedNamespace(const char* caller_location) {
auto name = nativeloader::FindApexNamespaceName(caller_location);
if (name.ok()) {
android_namespace_t* boot_namespace = android_get_exported_namespace(name->c_str());
LOG_ALWAYS_FATAL_IF((boot_namespace == nullptr),
"Error finding namespace of apex: no namespace called %s", name->c_str());
return boot_namespace;
}
return nullptr;
}
Result<void> CreateNativeloaderDefaultNamespaceLibsLink(NativeLoaderNamespace& ns)
REQUIRES(g_namespaces_mutex) {
const char* links = getenv("NATIVELOADER_DEFAULT_NAMESPACE_LIBS");
if (links == nullptr || *links == 0) {
return {};
}
// Pass nullptr to Link() to create a link to the default namespace without
// requiring it to be visible.
return ns.Link(nullptr, links);
}
Result<NativeLoaderNamespace*> GetNativeloaderExtraLibsNamespace() REQUIRES(g_namespaces_mutex) {
if (g_nativeloader_extra_libs_namespace != nullptr) {
return g_nativeloader_extra_libs_namespace;
}
Result<NativeLoaderNamespace> ns =
NativeLoaderNamespace::Create(kNativeloaderExtraLibs,
/*search_paths=*/"",
/*permitted_paths=*/"",
/*parent=*/nullptr,
/*is_shared=*/false,
/*is_exempt_list_enabled=*/false,
/*also_used_as_anonymous=*/false);
if (!ns.ok()) {
return ns.error();
}
g_nativeloader_extra_libs_namespace = new NativeLoaderNamespace(std::move(ns.value()));
Result<void> linked =
CreateNativeloaderDefaultNamespaceLibsLink(*g_nativeloader_extra_libs_namespace);
if (!linked.ok()) {
return linked.error();
}
return g_nativeloader_extra_libs_namespace;
}
// If the given path matches a library in NATIVELOADER_DEFAULT_NAMESPACE_LIBS
// then load it in the nativeloader-extra-libs namespace, otherwise return
// nullptr without error.
Result<void*> TryLoadNativeloaderExtraLib(const char* path) {
const char* links = getenv("NATIVELOADER_DEFAULT_NAMESPACE_LIBS");
if (links == nullptr || *links == 0) {
return nullptr;
}
std::vector<std::string> lib_list = base::Split(links, ":");
if (std::find(lib_list.begin(), lib_list.end(), path) == lib_list.end()) {
return nullptr;
}
std::lock_guard<std::mutex> guard(g_namespaces_mutex);
Result<NativeLoaderNamespace*> ns = GetNativeloaderExtraLibsNamespace();
if (!ns.ok()) {
return ns.error();
}
return ns.value()->Load(path);
}
Result<NativeLoaderNamespace*> CreateClassLoaderNamespaceLocked(JNIEnv* env,
int32_t target_sdk_version,
jobject class_loader,
bool is_shared,
jstring dex_path,
jstring library_path,
jstring permitted_path,
jstring uses_library_list)
REQUIRES(g_namespaces_mutex) {
Result<NativeLoaderNamespace*> ns = g_namespaces->Create(env,
target_sdk_version,
class_loader,
is_shared,
dex_path,
library_path,
permitted_path,
uses_library_list);
if (!ns.ok()) {
return ns;
}
Result<void> linked = CreateNativeloaderDefaultNamespaceLibsLink(*ns.value());
if (!linked.ok()) {
return linked.error();
}
return ns;
}
#endif // #if defined(ART_TARGET_ANDROID)
} // namespace
void InitializeNativeLoader() {
#if defined(ART_TARGET_ANDROID)
std::lock_guard<std::mutex> guard(g_namespaces_mutex);
g_namespaces->Initialize();
#endif
}
void ResetNativeLoader() {
#if defined(ART_TARGET_ANDROID)
std::lock_guard<std::mutex> guard(g_namespaces_mutex);
g_namespaces->Reset();
delete g_nativeloader_extra_libs_namespace;
g_nativeloader_extra_libs_namespace = nullptr;
#endif
}
jstring CreateClassLoaderNamespace(JNIEnv* env, int32_t target_sdk_version, jobject class_loader,
bool is_shared, jstring dex_path, jstring library_path,
jstring permitted_path, jstring uses_library_list) {
#if defined(ART_TARGET_ANDROID)
std::lock_guard<std::mutex> guard(g_namespaces_mutex);
Result<NativeLoaderNamespace*> ns = CreateClassLoaderNamespaceLocked(env,
target_sdk_version,
class_loader,
is_shared,
dex_path,
library_path,
permitted_path,
uses_library_list);
if (!ns.ok()) {
return env->NewStringUTF(ns.error().message().c_str());
}
#else
UNUSED(env, target_sdk_version, class_loader, is_shared, dex_path, library_path, permitted_path,
uses_library_list);
#endif
return nullptr;
}
void* OpenNativeLibrary(JNIEnv* env, int32_t target_sdk_version, const char* path,
jobject class_loader, const char* caller_location, jstring library_path,
bool* needs_native_bridge, char** error_msg) {
#if defined(ART_TARGET_ANDROID)
UNUSED(target_sdk_version);
if (class_loader == nullptr) {
*needs_native_bridge = false;
if (caller_location != nullptr) {
android_namespace_t* boot_namespace = FindExportedNamespace(caller_location);
if (boot_namespace != nullptr) {
const android_dlextinfo dlextinfo = {
.flags = ANDROID_DLEXT_USE_NAMESPACE,
.library_namespace = boot_namespace,
};
void* handle = android_dlopen_ext(path, RTLD_NOW, &dlextinfo);
if (handle == nullptr) {
*error_msg = strdup(dlerror());
}
return handle;
}
}
// Check if the library is in NATIVELOADER_DEFAULT_NAMESPACE_LIBS and should
// be loaded from the kNativeloaderExtraLibs namespace.
{
Result<void*> handle = TryLoadNativeloaderExtraLib(path);
if (!handle.ok()) {
*error_msg = strdup(handle.error().message().c_str());
return nullptr;
}
if (handle.value() != nullptr) {
return handle.value();
}
}
// Fall back to the system namespace. This happens for preloaded JNI
// libraries in the zygote.
// TODO(b/185833744): Investigate if this should fall back to the app main
// namespace (aka anonymous namespace) instead.
void* handle = OpenSystemLibrary(path, RTLD_NOW);
if (handle == nullptr) {
*error_msg = strdup(dlerror());
}
return handle;
}
std::lock_guard<std::mutex> guard(g_namespaces_mutex);
NativeLoaderNamespace* ns;
if ((ns = g_namespaces->FindNamespaceByClassLoader(env, class_loader)) == nullptr) {
// This is the case where the classloader was not created by ApplicationLoaders
// In this case we create an isolated not-shared namespace for it.
Result<NativeLoaderNamespace*> isolated_ns =
CreateClassLoaderNamespaceLocked(env,
target_sdk_version,
class_loader,
/*is_shared=*/false,
/*dex_path=*/nullptr,
library_path,
/*permitted_path=*/nullptr,
/*uses_library_list=*/nullptr);
if (!isolated_ns.ok()) {
*error_msg = strdup(isolated_ns.error().message().c_str());
return nullptr;
} else {
ns = *isolated_ns;
}
}
return OpenNativeLibraryInNamespace(ns, path, needs_native_bridge, error_msg);
#else
UNUSED(env, target_sdk_version, class_loader, caller_location);
// Do some best effort to emulate library-path support. It will not
// work for dependencies.
//
// Note: null has a special meaning and must be preserved.
std::string c_library_path; // Empty string by default.
if (library_path != nullptr && path != nullptr && path[0] != '/') {
ScopedUtfChars library_path_utf_chars(env, library_path);
c_library_path = library_path_utf_chars.c_str();
}
std::vector<std::string> library_paths = base::Split(c_library_path, ":");
for (const std::string& lib_path : library_paths) {
*needs_native_bridge = false;
const char* path_arg;
std::string complete_path;
if (path == nullptr) {
// Preserve null.
path_arg = nullptr;
} else {
complete_path = lib_path;
if (!complete_path.empty()) {
complete_path.append("/");
}
complete_path.append(path);
path_arg = complete_path.c_str();
}
void* handle = dlopen(path_arg, RTLD_NOW);
if (handle != nullptr) {
return handle;
}
if (NativeBridgeIsSupported(path_arg)) {
*needs_native_bridge = true;
handle = NativeBridgeLoadLibrary(path_arg, RTLD_NOW);
if (handle != nullptr) {
return handle;
}
*error_msg = strdup(NativeBridgeGetError());
} else {
*error_msg = strdup(dlerror());
}
}
return nullptr;
#endif
}
bool CloseNativeLibrary(void* handle, const bool needs_native_bridge, char** error_msg) {
bool success;
if (needs_native_bridge) {
success = (NativeBridgeUnloadLibrary(handle) == 0);
if (!success) {
*error_msg = strdup(NativeBridgeGetError());
}
} else {
success = (dlclose(handle) == 0);
if (!success) {
*error_msg = strdup(dlerror());
}
}
return success;
}
void NativeLoaderFreeErrorMessage(char* msg) {
// The error messages get allocated through strdup, so we must call free on them.
free(msg);
}
#if defined(ART_TARGET_ANDROID)
void* OpenNativeLibraryInNamespace(NativeLoaderNamespace* ns, const char* path,
bool* needs_native_bridge, char** error_msg) {
auto handle = ns->Load(path);
if (!handle.ok() && error_msg != nullptr) {
*error_msg = strdup(handle.error().message().c_str());
}
if (needs_native_bridge != nullptr) {
*needs_native_bridge = ns->IsBridged();
}
return handle.ok() ? *handle : nullptr;
}
// native_bridge_namespaces are not supported for callers of this function.
// This function will return nullptr in the case when application is running
// on native bridge.
android_namespace_t* FindNamespaceByClassLoader(JNIEnv* env, jobject class_loader) {
std::lock_guard<std::mutex> guard(g_namespaces_mutex);
NativeLoaderNamespace* ns = g_namespaces->FindNamespaceByClassLoader(env, class_loader);
if (ns != nullptr && !ns->IsBridged()) {
return ns->ToRawAndroidNamespace();
}
return nullptr;
}
NativeLoaderNamespace* FindNativeLoaderNamespaceByClassLoader(JNIEnv* env, jobject class_loader) {
std::lock_guard<std::mutex> guard(g_namespaces_mutex);
return g_namespaces->FindNamespaceByClassLoader(env, class_loader);
}
void LinkNativeLoaderNamespaceToExportedNamespaceLibrary(struct NativeLoaderNamespace* ns,
const char* exported_ns_name,
const char* library_name,
char** error_msg) {
Result<NativeLoaderNamespace> exported_ns =
NativeLoaderNamespace::GetExportedNamespace(exported_ns_name, ns->IsBridged());
if (!exported_ns.ok()) {
*error_msg = strdup(exported_ns.error().message().c_str());
return;
}
Result<void> linked = ns->Link(&exported_ns.value(), std::string(library_name));
if (!linked.ok()) {
*error_msg = strdup(linked.error().message().c_str());
}
}
#endif // ART_TARGET_ANDROID
}; // namespace android