121 lines
4.2 KiB
C++
121 lines
4.2 KiB
C++
/*
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* Copyright (C) 2021 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include <android-base/logging.h>
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#include <android-base/result.h>
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#include <android/dlext.h>
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#include <dlfcn.h>
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#include <cstdlib>
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#include <iostream>
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#include <string>
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#include "vm_main.h"
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using android::base::Error;
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using android::base::Result;
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extern "C" {
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enum {
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ANDROID_NAMESPACE_TYPE_REGULAR = 0,
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ANDROID_NAMESPACE_TYPE_ISOLATED = 1,
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ANDROID_NAMESPACE_TYPE_SHARED = 2,
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};
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extern struct android_namespace_t* android_create_namespace(
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const char* name, const char* ld_library_path, const char* default_library_path,
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uint64_t type, const char* permitted_when_isolated_path,
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struct android_namespace_t* parent);
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extern bool android_link_namespaces(struct android_namespace_t* from,
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struct android_namespace_t* to,
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const char* shared_libs_sonames);
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} // extern "C"
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static Result<void*> load(const std::string& libname);
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constexpr char entrypoint_name[] = "AVmPayload_main";
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static constexpr const char* kAllowedLibs[] = {
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"libc.so", "libm.so", "libdl.so", "libdl_android.so",
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"liblog.so", "libvm_payload.so", "libbinder_ndk.so", "libbinder_rpc_unstable.so",
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};
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int main(int argc, char* argv[]) {
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if (argc != 2) {
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std::cout << "Usage:\n";
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std::cout << " " << argv[0] << " LIBNAME\n";
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return EXIT_FAILURE;
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}
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android::base::InitLogging(argv, &android::base::KernelLogger);
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const char* libname = argv[1];
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auto handle = load(libname);
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if (!handle.ok()) {
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LOG(ERROR) << "Failed to load " << libname << ": " << handle.error().message();
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return EXIT_FAILURE;
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}
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AVmPayload_main_t* entry = reinterpret_cast<decltype(entry)>(dlsym(*handle, entrypoint_name));
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if (entry == nullptr) {
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LOG(ERROR) << "Failed to find entrypoint `" << entrypoint_name << "`: " << dlerror();
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return EXIT_FAILURE;
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}
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return entry();
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}
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// Create a new linker namespace whose search path is set to the directory of the library. Then
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// load it from there. Returns the handle to the loaded library if successful. Returns nullptr
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// if failed.
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Result<void*> load(const std::string& libname) {
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// Parent as nullptr means the default namespace
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android_namespace_t* parent = nullptr;
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// The search paths of the new namespace are isolated to restrict system private libraries.
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const uint64_t type = ANDROID_NAMESPACE_TYPE_ISOLATED;
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// The directory of the library is appended to the search paths
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const std::string libdir = libname.substr(0, libname.find_last_of("/"));
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const char* ld_library_path = libdir.c_str();
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const char* default_library_path = libdir.c_str();
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android_namespace_t* new_ns = nullptr;
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new_ns = android_create_namespace("microdroid_app", ld_library_path, default_library_path, type,
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/* permitted_when_isolated_path */ nullptr, parent);
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if (new_ns == nullptr) {
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return Error() << "Failed to create linker namespace: " << dlerror();
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}
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std::string libs;
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for (const char* lib : kAllowedLibs) {
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if (!libs.empty()) libs += ':';
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libs += lib;
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}
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if (!android_link_namespaces(new_ns, nullptr, libs.c_str())) {
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return Error() << "Failed to link namespace: " << dlerror();
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}
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const android_dlextinfo info = {
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.flags = ANDROID_DLEXT_USE_NAMESPACE,
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.library_namespace = new_ns,
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};
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if (auto ret = android_dlopen_ext(libname.c_str(), RTLD_NOW, &info); ret) {
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return ret;
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} else {
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return Error() << "Failed to dlopen: " << dlerror();
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}
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}
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