ws2_32: Fix ioctlsocket(FIONREAD) with listening socket.

dlls/ws2_32/socket.c

@@ -4648,12 +4648,24 @@ INT WINAPI WSAIoctl(SOCKET s, DWORD code, LPVOID in_buff, DWORD in_size, LPVOID
 
     case WS_FIONREAD:
     {
+#if defined(linux)
+        int listening = 0;
+        socklen_t len = sizeof(listening);
+#endif
         if (out_size != sizeof(WS_u_long) || IS_INTRESOURCE(out_buff))
         {
             SetLastError(WSAEFAULT);
             return SOCKET_ERROR;
         }
         if ((fd = get_sock_fd( s, 0, NULL )) == -1) return SOCKET_ERROR;
+
+#if defined(linux)
+        /* On Linux, FIONREAD on listening socket always fails (see tcp(7)).
+           However, it succeeds on native. */
+        if (!getsockopt( fd, SOL_SOCKET, SO_ACCEPTCONN, &listening, &len ) && listening)
+            (*(WS_u_long *) out_buff) = 0;
+        else
+#endif
         if (ioctl(fd, FIONREAD, out_buff ) == -1)
             status = wsaErrno();
         release_sock_fd( s, fd );

dlls/ws2_32/tests/sock.c

@@ -5233,8 +5233,8 @@ static void test_ioctlsocket(void)
     /* test FIONREAD with listening socket */
     arg = 0xdeadbeef;
     ret = ioctlsocket(sock, FIONREAD, &arg);
-    todo_wine ok(ret == 0, "ioctlsocket failed unexpectedly with error %d\n", WSAGetLastError());
-    todo_wine ok(arg == 0, "expected 0, got %u\n", arg);
+    ok(ret == 0, "ioctlsocket failed unexpectedly with error %d\n", WSAGetLastError());
+    ok(arg == 0, "expected 0, got %u\n", arg);
 
     closesocket(sock);