Stash fd in epoll_event instead of pointer in server

src/server.cpp

@@ -120,7 +120,7 @@ void Server::receiveConnectionBack(Connection *connection) {
   }
 
   connection->tsan_release();
-  event.data.ptr = connection;
+  event.data.fd = connection->getFd();
 
   // Distribute connections round-robin across epoll instances
   size_t epoll_index =
@@ -295,7 +295,7 @@ void Server::create_epoll_instances() {
     // Add shutdown pipe to each epoll instance
     struct epoll_event shutdown_event;
     shutdown_event.events = EPOLLIN;
-    shutdown_event.data.ptr = const_cast<char *>(&shutdown_pipe_tag);
+    shutdown_event.data.fd = shutdown_pipe_[0];
 
     if (epoll_ctl(epoll_fds_[i], EPOLL_CTL_ADD, shutdown_pipe_[0],
                   &shutdown_event) == -1) {
@@ -307,7 +307,7 @@ void Server::create_epoll_instances() {
     // thundering herd
     struct epoll_event listen_event;
     listen_event.events = EPOLLIN | EPOLLEXCLUSIVE;
-    listen_event.data.ptr = const_cast<char *>(&listen_socket_tag);
+    listen_event.data.fd = listen_sockfd_;
     if (epoll_ctl(epoll_fds_[i], EPOLL_CTL_ADD, listen_sockfd_,
                   &listen_event) == -1) {
       perror("epoll_ctl listen socket");
@@ -351,22 +351,20 @@ void Server::start_io_threads(std::vector<std::thread> &threads) {
         int batch_count = 0;
         for (int i = 0; i < event_count; ++i) {
           // Check for shutdown event
-          if (events[i].data.ptr == &shutdown_pipe_tag) {
+          if (events[i].data.fd == shutdown_pipe_[0]) {
             return;
           }
           // Check for new connections
-          if (events[i].data.ptr == &listen_socket_tag) {
+          if (events[i].data.fd == listen_sockfd_) {
             listenReady = true;
             continue;
           }
 
           // Handle existing connection events
-          std::unique_ptr<Connection> conn;
-          {
-            // borrowed
-            Connection *conn_ = static_cast<Connection *>(events[i].data.ptr);
-            conn_->tsan_acquire();
-            conn = connection_registry_.remove(conn_->getFd());
+          int fd = events[i].data.fd;
+          std::unique_ptr<Connection> conn = connection_registry_.remove(fd);
+          if (conn) {
+            conn->tsan_acquire();
           }
 
           if (events[i].events & (EPOLLERR | EPOLLHUP)) {
@@ -529,7 +527,7 @@ void Server::process_connection_batch(
       }
 
       conn_ptr->tsan_release();
-      event.data.ptr = conn_ptr.get(); // Use raw pointer for epoll
+      event.data.fd = fd; // Use file descriptor for epoll
       // Put connection back in registry since handler didn't take ownership.
       // Must happen before epoll_ctl
       connection_registry_.store(fd, std::move(conn_ptr));

src/server.hpp

@@ -118,10 +118,6 @@ private:
   std::vector<int> epoll_fds_;
   int listen_sockfd_ = -1;
 
-  // Unique tags for special events to avoid type confusion in epoll data union
-  static inline const char listen_socket_tag = 0;
-  static inline const char shutdown_pipe_tag = 0;
-
   // Private helper methods
   void setup_shutdown_pipe();
   void setup_signal_handling();