ueventd: add tests for setegid()/setfscreatecon() and threads

        "init_test.cpp",

        "property_service_test.cpp",

        "service_test.cpp",

        "ueventd_test.cpp",

        "util_test.cpp",

    ],

    shared_libs: [

/*

 * Copyright (C) 2017 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.

 */

#include <linux/futex.h>

#include <pthread.h>

#include <sys/stat.h>

#include <unistd.h>

#include <string>

#include <thread>

#include <vector>

#include <android-base/file.h>

#include <android-base/scopeguard.h>

#include <android-base/test_utils.h>

#include <gtest/gtest.h>

#include <selinux/selinux.h>

using namespace std::string_literals;

template <typename T, typename F>

void WriteFromMultipleThreads(std::vector<std::pair<std::string, T>>& files_and_parameters,

                              F function) {

    auto num_threads = files_and_parameters.size();

    pthread_barrier_t barrier;

    pthread_barrier_init(&barrier, nullptr, num_threads);

    auto barrier_destroy =

        android::base::make_scope_guard([&barrier]() { pthread_barrier_destroy(&barrier); });

    auto make_thread_function = [&function, &barrier](const auto& file, const auto& parameter) {

        return [&]() {

            function(parameter);

            pthread_barrier_wait(&barrier);

            android::base::WriteStringToFile("<empty>", file);

        };

    };

    std::vector<std::thread> threads;

    // TODO(b/63712782): Structured bindings + templated containers are broken in clang :(

    // for (const auto& [file, parameter] : files_and_parameters) {

    for (const auto& pair : files_and_parameters) {

        const auto& file = pair.first;

        const auto& parameter = pair.second;

        threads.emplace_back(std::thread(make_thread_function(file, parameter)));

    }

    for (auto& thread : threads) {

        thread.join();

    }

}

TEST(ueventd, setegid_IsPerThread) {

    if (getuid() != 0) return;

    TemporaryDir dir;

    gid_t gid = 0;

    std::vector<std::pair<std::string, gid_t>> files_and_gids;

    std::generate_n(std::back_inserter(files_and_gids), 100, [&gid, &dir]() {

        gid++;

        return std::pair(dir.path + "/gid_"s + std::to_string(gid), gid);

    });

    WriteFromMultipleThreads(files_and_gids, [](gid_t gid) { EXPECT_EQ(0, setegid(gid)); });

    for (const auto& [file, expected_gid] : files_and_gids) {

        struct stat info;

        EXPECT_EQ(0, stat(file.c_str(), &info));

        EXPECT_EQ(expected_gid, info.st_gid);

    }

}

TEST(ueventd, setfscreatecon_IsPerThread) {

    if (getuid() != 0) return;

    const char* const contexts[] = {

        "u:object_r:audio_device:s0",

        "u:object_r:sensors_device:s0",

        "u:object_r:video_device:s0"

        "u:object_r:zero_device:s0",

    };

    TemporaryDir dir;

    std::vector<std::pair<std::string, std::string>> files_and_contexts;

    for (const char* context : contexts) {

        files_and_contexts.emplace_back(dir.path + "/context_"s + context, context);

    }

    WriteFromMultipleThreads(files_and_contexts, [](const std::string& context) {

        EXPECT_EQ(0, setfscreatecon(context.c_str()));

    });

    for (const auto& [file, expected_context] : files_and_contexts) {

        char* file_context;

        EXPECT_GT(getfilecon(file.c_str(), &file_context), 0);

        EXPECT_EQ(expected_context, file_context);

        freecon(file_context);

    }

}