Add accept_socket() to tcp and tls servers

This will allow for a graceful shutdown via the socket.shutdown(how)
functions

Closes #377

Author: jbaldwin

include/coro/net/socket.hpp

@@ -68,7 +68,7 @@ class socket
 
     /**
      * @param how Shuts the socket down with the given operations.
-     * @param Returns true if the sockets given operations were shutdown.
+     * @return Returns true if the sockets given operations were shutdown.
      */
     auto shutdown(poll_op how = poll_op::read_write) -> bool;
 

include/coro/net/tcp/client.hpp

@@ -52,8 +52,8 @@ class client
      * @return The tcp socket this client is using.
      * @{
      **/
-    auto socket() -> net::socket& { return m_socket; }
-    auto socket() const -> const net::socket& { return m_socket; }
+    [[nodiscard]] auto socket() -> net::socket& { return m_socket; }
+    [[nodiscard]] auto socket() const -> const net::socket& { return m_socket; }
     /** @} */
 
     /**

include/coro/net/tcp/server.hpp

@@ -56,11 +56,19 @@ class server
 
     /**
      * Accepts an incoming tcp client connection.  On failure the tls clients socket will be set to
-     * and invalid state, use the socket.is_value() to verify the client was correctly accepted.
+     * and invalid state, use the socket.is_valid() to verify the client was correctly accepted.
      * @return The newly connected tcp client connection.
      */
     auto accept() -> coro::net::tcp::client;
 
+    /**
+     * @return The tcp accept socket this server is using.
+     * @{
+     **/
+    [[nodiscard]] auto accept_socket() -> net::socket& { return m_accept_socket; }
+    [[nodiscard]] auto accept_socket() const -> const net::socket& { return m_accept_socket; }
+    /** @} */
+
 private:
     friend client;
     /// The io scheduler for awaiting new connections.

include/coro/net/tls/client.hpp

@@ -58,8 +58,8 @@ class client
      * @return The tcp socket this client is using.
      * @{
      **/
-    auto socket() -> net::socket& { return m_socket; }
-    auto socket() const -> const net::socket& { return m_socket; }
+    [[nodiscard]] auto socket() -> net::socket& { return m_socket; }
+    [[nodiscard]] auto socket() const -> const net::socket& { return m_socket; }
     /** @} */
 
     /**

include/coro/net/tls/server.hpp

@@ -66,6 +66,14 @@ class server
      */
     auto accept(std::chrono::milliseconds timeout = std::chrono::seconds{30}) -> coro::task<coro::net::tls::client>;
 
+    /**
+     * @return The tcp accept socket this server is using.
+     * @{
+     **/
+    [[nodiscard]] auto accept_socket() -> net::socket& { return m_accept_socket; }
+    [[nodiscard]] auto accept_socket() const -> const net::socket& { return m_accept_socket; }
+    /** @} */
+
 private:
     /// The io scheduler for awaiting new connections.
     std::shared_ptr<io_scheduler> m_io_scheduler{nullptr};

src/detail/io_notifier_epoll.cpp

@@ -65,7 +65,7 @@ auto io_notifier_epoll::watch(fd_t fd, coro::poll_op op, void* data, bool keep)
 auto io_notifier_epoll::watch(detail::poll_info& pi) -> bool
 {
     auto event_data     = event_t{};
-    event_data.events   = static_cast<uint32_t>(pi.m_op) | EPOLLONESHOT | EPOLLRDHUP;
+    event_data.events   = static_cast<uint32_t>(pi.m_op) | EPOLLONESHOT | EPOLLRDHUP | EPOLLHUP;
     event_data.data.ptr = static_cast<void*>(&pi);
     return ::epoll_ctl(m_fd, EPOLL_CTL_ADD, pi.m_fd, &event_data) != -1;
 }

test/net/test_tcp_server.cpp

@@ -175,4 +175,30 @@ TEST_CASE("tcp_server concurrent polling on the same socket", "[tcp_server]")
     REQUIRE(request == response);
 }
 
+TEST_CASE("tcp_server graceful shutdown via socket", "[tcp_server]")
+{
+    auto scheduler = coro::io_scheduler::make_shared(coro::io_scheduler::options{
+        .execution_strategy = coro::io_scheduler::execution_strategy_t::process_tasks_inline});
+    coro::net::tcp::server server{scheduler};
+
+    auto make_accept_task = [](coro::net::tcp::server& server) -> coro::task<void>
+    {
+        std::cerr << "make accept task start\n";
+        auto poll_result = co_await server.poll(std::chrono::seconds{3});
+        REQUIRE(poll_result == coro::poll_status::closed);
+        auto client = server.accept();
+        REQUIRE_FALSE(client.socket().is_valid());
+        std::cerr << "make accept task completed\n";
+    };
+
+    scheduler->spawn(make_accept_task(server));
+
+    std::this_thread::sleep_for(std::chrono::milliseconds(100));
+
+    server.accept_socket().shutdown(coro::poll_op::read_write);
+
+    scheduler->shutdown();
+}
+
 #endif // LIBCORO_FEATURE_NETWORKING
+