From: bert hubert <bert.hubert@netherlabs.nl>
Date: Mon, 16 Dec 2013 12:19:52 +0000 (+0100)
Subject: ok, so it turns out that poll, select and a few other system calls can return EINTR... 
X-Git-Tag: rec-3.6.0-rc1~293
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=ee79512a7282c533cd4ae8be7f540ec721d2975d;p=pdns

ok, so it turns out that poll, select and a few other system calls can return EINTR when we receive and interrupt, and we need to manually restart. man 7 signal makes for good reading on this case, as does http://blog.reverberate.org/2011/04/eintr-and-pc-loser-ing-is-better-case.html
---

diff --git a/pdns/nameserver.cc b/pdns/nameserver.cc
index 9c9eddf32..39c85a83a 100644
--- a/pdns/nameserver.cc
+++ b/pdns/nameserver.cc
@@ -410,9 +410,14 @@ DNSPacket *UDPNameserver::receive(DNSPacket *prefilled)
     pfd.revents = 0;
   }
     
+  retry:;
+  
   err = poll(&rfds[0], rfds.size(), -1);
-  if(err < 0)
+  if(err < 0) {
+    if(errno==EINTR)
+      goto retry;
     unixDie("Unable to poll for new UDP events");
+  }
     
   BOOST_FOREACH(struct pollfd &pfd, rfds) {
     if(pfd.revents & POLLIN) {