From 3b07fd1b5888aec853e98da89edc016d6c465132 Mon Sep 17 00:00:00 2001
From: Remi Gacogne <remi.gacogne@powerdns.com>
Date: Thu, 21 Mar 2019 18:36:33 +0100
Subject: [PATCH] dnsdist: Make sure that the TCP distribution pipes are
 non-blocking

---
 pdns/dnsdist-tcp.cc | 7 +++++++
 pdns/dnsdist.hh     | 8 ++++++++
 2 files changed, 15 insertions(+)

diff --git a/pdns/dnsdist-tcp.cc b/pdns/dnsdist-tcp.cc
index 35f7c19a86..9889583e98 100644
--- a/pdns/dnsdist-tcp.cc
+++ b/pdns/dnsdist-tcp.cc
@@ -209,6 +209,13 @@ void TCPClientCollection::addTCPClientThread()
       return;
     }
 
+    if (!setNonBlocking(pipefds[0])) {
+      close(pipefds[0]);
+      close(pipefds[1]);
+      errlog("Error setting the TCP thread communication pipe non-blocking: %s", strerror(errno));
+      return;
+    }
+
     if (!setNonBlocking(pipefds[1])) {
       close(pipefds[0]);
       close(pipefds[1]);
diff --git a/pdns/dnsdist.hh b/pdns/dnsdist.hh
index eed5d46940..f76888c09c 100644
--- a/pdns/dnsdist.hh
+++ b/pdns/dnsdist.hh
@@ -636,6 +636,14 @@ public:
       if (pipe(d_singlePipe) < 0) {
         throw std::runtime_error("Error creating the TCP single communication pipe: " + string(strerror(errno)));
       }
+
+      if (!setNonBlocking(d_singlePipe[0])) {
+        int err = errno;
+        close(d_singlePipe[0]);
+        close(d_singlePipe[1]);
+        throw std::runtime_error("Error setting the TCP single communication pipe non-blocking: " + string(strerror(err)));
+      }
+
       if (!setNonBlocking(d_singlePipe[1])) {
         int err = errno;
         close(d_singlePipe[0]);
-- 
2.47.2