/*
 * Copyright (C) 2020 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 <errno.h>
#include <sys/socket.h>
#include <unistd.h>

#include <linux/vm_sockets.h>

#include <cstdlib>
#include <cstring>
#include <iostream>

static constexpr const char LOG_TAG[] = "VsockTest: ";
static constexpr int VSOCK_TEST_PORT = 4455;
static constexpr int VSOCK_TEST_CID = 42;
static constexpr const char VSOCK_TEST_MSG[] = "VsockTestMessage\n";

int VsockServer() {
    int fd, ret;
    struct sockaddr_vm sa = (struct sockaddr_vm) {
        .svm_family = AF_VSOCK,
        .svm_port = VSOCK_TEST_PORT,
        .svm_cid = VSOCK_TEST_CID,
    };
    char buf[1024];
    size_t buf_used = 0;

    fd = socket(AF_VSOCK, SOCK_STREAM, 0);
    if (fd < 0) {
        std::cerr << "ERROR: socket: " << strerror(errno) << std::endl;
        return EXIT_FAILURE;
    }

    std::cerr << LOG_TAG << "Establishing a vsock connection..." << std::endl;

    ret = connect(fd, (struct sockaddr*)&sa, sizeof(sa));
    if (ret != 0) {
        std::cerr << "ERROR: connect: " << strerror(errno) << std::endl;
        close(fd);
        return EXIT_FAILURE;
    }

    std::cerr << LOG_TAG << "Reading message from guest..." << std::endl;

    while (true) {
        ssize_t n = read(fd, buf + buf_used, sizeof(buf) - buf_used);

        if (n == 0) {
            break;
        } else if (n < 0) {
            close(fd);
            return EXIT_FAILURE;
        }

        buf_used += n;
    }

    close(fd);

    std::cerr << LOG_TAG << "Message from guest: " << buf << std::endl;
    if ((buf_used == sizeof(VSOCK_TEST_MSG)) &&
        memcmp(VSOCK_TEST_MSG, buf, sizeof(VSOCK_TEST_MSG)) == 0) {
        std::cerr << LOG_TAG << "Message match" << std::endl;
        return EXIT_SUCCESS;
    } else {
        std::cerr << LOG_TAG << "Message mismatch" << std::endl;
        return EXIT_FAILURE;
    }
}