Integrate the monitor's listener socket into the shard's poll()

This removes the need for a separate monitor thread.

src/CNProtocol.cpp

@@ -219,7 +219,7 @@ bool setSockNonblocking(SOCKET listener, SOCKET newSock) {
     unsigned long mode = 1;
     if (ioctlsocket(newSock, FIONBIO, &mode) != 0) {
 #else
-    if (fcntl(newSock, F_SETFL, (fcntl(listener, F_GETFL, 0) | O_NONBLOCK)) != 0) {
+    if (fcntl(newSock, F_SETFL, (fcntl(newSock, F_GETFL, 0) | O_NONBLOCK)) != 0) {
 #endif
         std::cerr << "[WARN] OpenFusion: fcntl failed on new connection" << std::endl;
 #ifdef _WIN32
@@ -351,6 +351,9 @@ void CNServer::start() {
                 connections[newConnectionSocket] = tmp;
                 newConnection(tmp);
 
+            } else if (checkExtraSockets(i)) {
+                // no-op. handled in checkExtraSockets().
+
             } else {
                 // player sockets
                 if (connections.find(fds[i].fd) == connections.end()) {
@@ -419,6 +422,7 @@ void CNServer::printPacket(CNPacketData *data, int type) {
     std::cout << "OpenFusion: received " << Defines::p2str(type, data->type) << " (" << data->type << ")" << std::endl;
 }
 
+bool CNServer::checkExtraSockets(int i) { return false; } // stubbed
 void CNServer::newConnection(CNSocket* cns) {} // stubbed
 void CNServer::killConnection(CNSocket* cns) {} // stubbed
 void CNServer::onStep() {} // stubbed

src/CNProtocol.hpp

@@ -223,6 +223,7 @@ public:
     void start();
     void kill();
     static void printPacket(CNPacketData *data, int type);
+    virtual bool checkExtraSockets(int i);
     virtual void newConnection(CNSocket* cns);
     virtual void killConnection(CNSocket* cns);
     virtual void onStep();

src/CNShardServer.cpp

@@ -6,6 +6,7 @@
 #include "CNShared.hpp"
 #include "settings.hpp"
 #include "Database.hpp"
+#include "Monitor.hpp"
 #include "TableData.hpp" // for flush()
 
 #include <iostream>
@@ -21,6 +22,9 @@ CNShardServer::CNShardServer(uint16_t p) {
     REGISTER_SHARD_TIMER(keepAliveTimer, 4000);
     REGISTER_SHARD_TIMER(periodicSaveTimer, settings::DBSAVEINTERVAL*1000);
     init();
+
+    if (settings::MONITORENABLED)
+        fds.push_back({Monitor::init(), POLLIN});
 }
 
 void CNShardServer::handlePacket(CNSocket* sock, CNPacketData* data) {
@@ -62,6 +66,10 @@ void CNShardServer::periodicSaveTimer(CNServer* serv, time_t currTime) {
     std::cout << "[INFO] Done." << std::endl;
 }
 
+bool CNShardServer::checkExtraSockets(int i) {
+    return Monitor::acceptConnection(fds[i].fd, fds[i].revents);
+}
+
 void CNShardServer::newConnection(CNSocket* cns) {
     cns->setActiveKey(SOCKETKEY_E); // by default they accept keys encrypted with the default key
 }

src/CNShardServer.hpp

@@ -23,6 +23,7 @@ public:
 
     static void _killConnection(CNSocket *cns);
 
+    bool checkExtraSockets(int i);
     void newConnection(CNSocket* cns);
     void killConnection(CNSocket* cns);
     void kill();

src/Monitor.cpp

@@ -6,16 +6,12 @@
 
 #include <cstdio>
 
-static int listener;
+static SOCKET listener;
 static std::mutex sockLock; // guards socket list
 static std::list<SOCKET> sockets;
 static sockaddr_in address;
 
-// runs during init
-void Monitor::init() {
-    if (!settings::MONITORENABLED)
-        return;
-
+SOCKET Monitor::init() {
     listener = socket(AF_INET, SOCK_STREAM, 0);
     if (SOCKETERROR(listener)) {
         std::cout << "Failed to create monitor socket" << std::endl;
@@ -59,6 +55,8 @@ void Monitor::init() {
     std::cout << "Monitor listening on *:" << settings::MONITORPORT << std::endl;
 
     REGISTER_SHARD_TIMER(tick, settings::MONITORINTERVAL);
+
+    return listener;
 }
 
 static bool transmit(std::list<SOCKET>::iterator& it, char *buff, int len) {
@@ -86,7 +84,6 @@ static bool transmit(std::list<SOCKET>::iterator& it, char *buff, int len) {
     return true;
 }
 
-// runs in shard thread
 void Monitor::tick(CNServer *serv, time_t delta) {
     std::lock_guard<std::mutex> lock(sockLock);
     char buff[256];
@@ -115,26 +112,33 @@ void Monitor::tick(CNServer *serv, time_t delta) {
     }
 }
 
-// runs in monitor thread
-void Monitor::start(void *unused) {
+bool Monitor::acceptConnection(SOCKET fd, uint16_t revents) {
     socklen_t len = sizeof(address);
 
     if (!settings::MONITORENABLED)
-        return;
+        return false;
 
-    for (;;) {
-        int sock = accept(listener, (struct sockaddr*)&address, &len);
-        if (SOCKETERROR(sock))
-            continue;
+    if (fd != listener)
+        return false;
 
-        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);
-        }
+    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))
+        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;
 }

src/Monitor.hpp

@@ -6,7 +6,7 @@
 #include <mutex>
 
 namespace Monitor {
-    void init();
+    SOCKET init();
     void tick(CNServer *, time_t);
-    void start(void *);
+    bool acceptConnection(SOCKET, uint16_t);
 };

src/main.cpp

@@ -38,8 +38,6 @@
 CNShardServer *shardServer = nullptr;
 std::thread *shardThread = nullptr;
 
-std::thread *monitorThread = nullptr;
-
 void startShard(CNShardServer* server) {
     server->start();
 }
@@ -104,7 +102,6 @@ int main() {
     TransportManager::init();
     BuddyManager::init();
     GroupManager::init();
-    Monitor::init();
     Database::open();
 
     switch (settings::EVENTMODE) {
@@ -123,7 +120,6 @@ int main() {
     shardServer = new CNShardServer(settings::SHARDPORT);
 
     shardThread = new std::thread(startShard, (CNShardServer*)shardServer);
-    monitorThread = new std::thread(Monitor::start, nullptr);
 
     loginServer.start();