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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
*
* 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 "native_loader_namespace.h"
#include <dlfcn.h>
#include <functional>
#include <android-base/strings.h>
#include <log/log.h>
#include <nativebridge/native_bridge.h>
#include "nativeloader/dlext_namespaces.h"
using android::base::Error;
namespace android {
namespace {
constexpr const char* kDefaultNamespaceName = "default";
constexpr const char* kSystemNamespaceName = "system";
std::string GetLinkerError(bool is_bridged) {
const char* msg = is_bridged ? NativeBridgeGetError() : dlerror();
if (msg == nullptr) {
return "no error";
}
return std::string(msg);
}
} // namespace
Result<NativeLoaderNamespace> NativeLoaderNamespace::GetExportedNamespace(const std::string& name,
bool is_bridged) {
if (!is_bridged) {
auto raw = android_get_exported_namespace(name.c_str());
if (raw != nullptr) {
return NativeLoaderNamespace(name, raw);
}
} else {
auto raw = NativeBridgeGetExportedNamespace(name.c_str());
if (raw != nullptr) {
return NativeLoaderNamespace(name, raw);
}
}
return Errorf("namespace {} does not exist or exported", name);
}
// The system namespace is called "default" for binaries in /system and
// "system" for those in the Runtime APEX. Try "system" first since
// "default" always exists.
Result<NativeLoaderNamespace> NativeLoaderNamespace::GetSystemNamespace(bool is_bridged) {
auto ns = GetExportedNamespace(kSystemNamespaceName, is_bridged);
if (ns.ok()) return ns;
ns = GetExportedNamespace(kDefaultNamespaceName, is_bridged);
if (ns.ok()) return ns;
// If nothing is found, return NativeLoaderNamespace constructed from nullptr.
// nullptr also means default namespace to the linker.
if (!is_bridged) {
return NativeLoaderNamespace(kDefaultNamespaceName, static_cast<android_namespace_t*>(nullptr));
} else {
return NativeLoaderNamespace(kDefaultNamespaceName,
static_cast<native_bridge_namespace_t*>(nullptr));
}
}
Result<NativeLoaderNamespace> NativeLoaderNamespace::Create(
const std::string& name, const std::string& search_paths, const std::string& permitted_paths,
const NativeLoaderNamespace* parent, bool is_shared, bool is_greylist_enabled,
bool also_used_as_anonymous) {
bool is_bridged = false;
if (parent != nullptr) {
is_bridged = parent->IsBridged();
} else if (!search_paths.empty()) {
is_bridged = NativeBridgeIsPathSupported(search_paths.c_str());
}
// Fall back to the system namespace if no parent is set.
auto system_ns = GetSystemNamespace(is_bridged);
if (!system_ns.ok()) {
return system_ns.error();
}
const NativeLoaderNamespace& effective_parent = parent != nullptr ? *parent : *system_ns;
// All namespaces for apps are isolated
uint64_t type = ANDROID_NAMESPACE_TYPE_ISOLATED;
// The namespace is also used as the anonymous namespace
// which is used when the linker fails to determine the caller address
if (also_used_as_anonymous) {
type |= ANDROID_NAMESPACE_TYPE_ALSO_USED_AS_ANONYMOUS;
}
// Bundled apps have access to all system libraries that are currently loaded
// in the default namespace
if (is_shared) {
type |= ANDROID_NAMESPACE_TYPE_SHARED;
}
if (is_greylist_enabled) {
type |= ANDROID_NAMESPACE_TYPE_GREYLIST_ENABLED;
}
if (!is_bridged) {
android_namespace_t* raw =
android_create_namespace(name.c_str(), nullptr, search_paths.c_str(), type,
permitted_paths.c_str(), effective_parent.ToRawAndroidNamespace());
if (raw != nullptr) {
return NativeLoaderNamespace(name, raw);
}
} else {
native_bridge_namespace_t* raw = NativeBridgeCreateNamespace(
name.c_str(), nullptr, search_paths.c_str(), type, permitted_paths.c_str(),
effective_parent.ToRawNativeBridgeNamespace());
if (raw != nullptr) {
return NativeLoaderNamespace(name, raw);
}
}
return Errorf("failed to create {} namespace name:{}, search_paths:{}, permitted_paths:{}",
is_bridged ? "bridged" : "native", name, search_paths, permitted_paths);
}
Result<void> NativeLoaderNamespace::Link(const NativeLoaderNamespace& target,
const std::string& shared_libs) const {
LOG_ALWAYS_FATAL_IF(shared_libs.empty(), "empty share lib when linking %s to %s",
this->name().c_str(), target.name().c_str());
if (!IsBridged()) {
if (android_link_namespaces(this->ToRawAndroidNamespace(), target.ToRawAndroidNamespace(),
shared_libs.c_str())) {
return {};
}
} else {
if (NativeBridgeLinkNamespaces(this->ToRawNativeBridgeNamespace(),
target.ToRawNativeBridgeNamespace(), shared_libs.c_str())) {
return {};
}
}
return Error() << GetLinkerError(IsBridged());
}
Result<void*> NativeLoaderNamespace::Load(const char* lib_name) const {
if (!IsBridged()) {
android_dlextinfo extinfo;
extinfo.flags = ANDROID_DLEXT_USE_NAMESPACE;
extinfo.library_namespace = this->ToRawAndroidNamespace();
void* handle = android_dlopen_ext(lib_name, RTLD_NOW, &extinfo);
if (handle != nullptr) {
return handle;
}
} else {
void* handle =
NativeBridgeLoadLibraryExt(lib_name, RTLD_NOW, this->ToRawNativeBridgeNamespace());
if (handle != nullptr) {
return handle;
}
}
return Error() << GetLinkerError(IsBridged());
}
} // namespace android
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