From 5e84ab064300f940e0c95de0200db98fa6fe6af3 Mon Sep 17 00:00:00 2001
From: "Alexander V. Chernikov" <melifaro@yandex-team.ru>
Date: Mon, 2 Nov 2015 23:56:33 +0300
Subject: [PATCH 1/1] Emit error and reject sockets not fitting in FD_SETSIZE
 limit.

---
 sysdep/unix/io.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/sysdep/unix/io.c b/sysdep/unix/io.c
index 0724667..5049b63 100644
--- a/sysdep/unix/io.c
+++ b/sysdep/unix/io.c
@@ -1328,6 +1328,17 @@ sk_passive_connected(sock *s, int type)
       log(L_WARN "SOCK: Cannot get remote IP address for TCP<");
   }
 
+  if (fd >= FD_SETSIZE)
+  {
+    log(L_ERR "SOCK: Incoming connection from %I%J (port %d) %s (%d)",
+      t->daddr, ipa_is_link_local(t->daddr) ? t->iface : NULL,
+      t->dport, "rejected due to FD_SETSIZE limit", FD_SETSIZE);
+    close(t->fd);
+    t->fd = -1;
+    rfree(t);
+    return 1;
+  }
+
   if (sk_setup(t) < 0)
   {
     /* FIXME: Call err_hook instead ? */
@@ -1404,6 +1415,12 @@ sk_open(sock *s)
   if (fd < 0)
     ERR("socket");
 
+  if (fd >= FD_SETSIZE)
+  {
+    log(L_ERR "Socket setup failed due to FD_SETSIZE limit (%d)", FD_SETSIZE);
+    ERR2("FD_SETSIZE limit reached");
+  }
+
   s->af = af;
   s->fd = fd;
 
-- 
2.6.1