From 23a2e84873a8aecb9d90c9f868a388858d191e9c Mon Sep 17 00:00:00 2001
From: Andreas Kling <awesomekling@gmail.com>
Date: Wed, 27 Nov 2019 16:01:22 +0100
Subject: [PATCH] Kernel: listen() should fail with EINVAL for
 already-connected sockets

This according to POSIX.
---
 Kernel/Process.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Kernel/Process.cpp b/Kernel/Process.cpp
index c4be91dcce..08ac19e057 100644
--- a/Kernel/Process.cpp
+++ b/Kernel/Process.cpp
@@ -2438,6 +2438,8 @@ int Process::sys$listen(int sockfd, int backlog)
     if (!description->is_socket())
         return -ENOTSOCK;
     auto& socket = *description->socket();
+    if (socket.is_connected())
+        return -EINVAL;
     return socket.listen(backlog);
 }