OpenFusion/src/servers/Monitor.cpp

#include "servers/CNShardServer.hpp"
#include "PlayerManager.hpp"
#include "Chat.hpp"
#include "Email.hpp"
#include "servers/Monitor.hpp"
#include "settings.hpp"

#include <cstdio>

static SOCKET listener;
static std::mutex sockLock; // guards socket list
static std::list<SOCKET> sockets;
static sockaddr_in address;

static bool transmit(std::list<SOCKET>::iterator& it, char *buff, int len) {
    int n = 0;
    int sock = *it;

    while (n < len) {
        n += send(sock, buff+n, len-n, 0);
        if (SOCKETERROR(n)) {
            printSocketError("send");

#ifdef _WIN32
            shutdown(sock, SD_BOTH);
            closesocket(sock);
#else
            shutdown(sock, SHUT_RDWR);
            close(sock);
#endif

            std::cout << "[INFO] Disconnected a monitor" << std::endl;

            it = sockets.erase(it);
            return false;
        }
    }

    return true;
}

/*
 * The longest protocol message is for an email.
 *
 * message type + two formatted character names + the other formatting chars
 * + the email title + the email body = ~1154
 *
 * The body can grow to twice its usual size (512) in the pathological case
 * where every character is a newline.
 *
 * Multi-byte Unicode characters aren't a factor, as they should've been
 * stripped out by sanitizeText().
 */
#define BUFSIZE 2048

static int process_email(char *buff, std::string email) {
    strncpy(buff, "email ", 6);
    int i = 6;

    for (char c : email) {
        if (i == BUFSIZE-2)
            break;

        buff[i++] = c;

        // indent each line to prevent "endemail" spoofing
        if (c == '\n')
            buff[i++] = '\t';
    }

    buff[i++] = '\n';
    return i;
}

static void tick(CNServer *serv, time_t delta) {
    std::lock_guard<std::mutex> lock(sockLock);
    char buff[BUFSIZE];
    int n;

    auto it = sockets.begin();
outer:
    while (it != sockets.end()) {
        if (!transmit(it, (char*)"begin\n", 6))
            continue;

        // player
        for (auto& pair : PlayerManager::players) {
            if (pair.second->hidden)
                continue;

            n = std::snprintf(buff, sizeof(buff), "player %d %d %s\n",
                    pair.second->x, pair.second->y,
                    PlayerManager::getPlayerName(pair.second, false).c_str());

            if (!transmit(it, buff, n))
                goto outer;
        }

        // chat
        for (auto& str : Chat::dump) {
            n = std::snprintf(buff, sizeof(buff), "chat %s\n", str.c_str());

            if (!transmit(it, buff, n))
                goto outer;
        }

        // emails
        for (auto& str : Email::dump) {
            n = process_email(buff, str);

            if (!transmit(it, buff, n))
                goto outer;

            if (!transmit(it, (char*)"endemail\n", 9))
                goto outer;
        }

        if (!transmit(it, (char*)"end\n", 4))
            continue;

        it++;
    }

    Chat::dump.clear();
    Email::dump.clear();
}

bool Monitor::acceptConnection(SOCKET fd, uint16_t revents) {
    socklen_t len = sizeof(address);

    if (!settings::MONITORENABLED)
        return false;

    if (fd != listener)
        return false;

    if (revents & ~POLLIN) {
        std::cout << "[FATAL] Error on monitor listener?" << std::endl;
        terminate(0);
    }

    int sock = accept(listener, (struct sockaddr*)&address, &len);
    if (SOCKETERROR(sock)) {
        printSocketError("accept");
        return true;
    }

    setSockNonblocking(listener, sock);

    std::cout << "[INFO] New monitor connection from " << inet_ntoa(address.sin_addr) << std::endl;

    {
        std::lock_guard<std::mutex> lock(sockLock);

        sockets.push_back(sock);
    }

    return true;
}

SOCKET Monitor::init() {
    listener = socket(AF_INET, SOCK_STREAM, 0);
    if (SOCKETERROR(listener)) {
        std::cout << "Failed to create monitor socket" << std::endl;
        printSocketError("socket");
        exit(1);
    }

#ifdef _WIN32
    const char opt = 1;
#else
    int opt = 1;
#endif
    if (SOCKETERROR(setsockopt(listener, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt)))) {
        std::cout << "Failed to set SO_REUSEADDR on monitor socket" << std::endl;
        printSocketError("setsockopt");
        exit(1);
    }

    address.sin_family = AF_INET;
    address.sin_addr.s_addr = INADDR_ANY;
    address.sin_port = htons(settings::MONITORPORT);

    if (SOCKETERROR(bind(listener, (struct sockaddr*)&address, sizeof(address)))) {
        std::cout << "Failed to bind to monitor port" << std::endl;
        printSocketError("bind");
        exit(1);
    }

    if (SOCKETERROR(listen(listener, SOMAXCONN))) {
        std::cout << "Failed to listen on monitor port" << std::endl;
        printSocketError("listen");
        exit(1);
    }

#ifdef _WIN32
    unsigned long mode = 1;
    if (ioctlsocket(listener, FIONBIO, &mode) != 0) {
#else
    if (fcntl(listener, F_SETFL, (fcntl(listener, F_GETFL, 0) | O_NONBLOCK)) != 0) {
#endif
        std::cerr << "[FATAL] OpenFusion: fcntl failed" << std::endl;
        printSocketError("fcntl");
        exit(EXIT_FAILURE);
    }

    std::cout << "Monitor listening on *:" << settings::MONITORPORT << std::endl;

    REGISTER_SHARD_TIMER(tick, settings::MONITORINTERVAL);

    return listener;
}