[Nagiosplug-devel] check_dns: DNS WARNING - nslookup returned error status

[Dag Wieers]

Hi,

We noticed a problem on some systems due to the fact that the 
process was already exited when issuing spclose() and spclose() didn't 
check this properly (followed by a non-zero return code, generating a 
warning). Causing the plugin to variably return:

	DNS WARNING - nslookup returned error status

This seems to be system-dependent (load/kernel scheduler). On RHEL3 we 
didn't see this, but with RHEL4's 2.6 kernel it happened frequently.

I noticed this is also reported on Sourceforge's bugtracker at:

	https://sourceforge.net/tracker/?func=detail&atid=397597&aid=1250191&group_id=29880

where they check if the process has already finished.

This would fix similar problems with check_dig and probably other checks, 
where you get warning messages as well, like:

	DNS WARNING - 0.008 seconds response time (servername. 600 IN A 1.2.3.4)|time=0.008382s;;;0.000000

This is a pretty urgent bug imo, warranting a new release ?

Kind regards,
--   dag wieers,  dag at wieers.com,  http://dag.wieers.com/   --
[all I want is a warm bed and a kind word and unlimited power]
-------------- next part --------------
--- nagios-plugins-1.4.1/plugins/popen.c.orig	2005-08-02 13:44:47.631761141 +0200
+++ nagios-plugins-1.4.1/plugins/popen.c	2005-08-02 13:52:24.589616713 +0200
@@ -221,8 +221,13 @@
 		return (1);
 
 	while (waitpid (pid, &status, 0) < 0)
+	{
+		if (errno == ECHILD)
+			return (0);							/* Child has already exited */
+
 		if (errno != EINTR)
 			return (1);							/* error other than EINTR from waitpid() */
+	}
 
 	if (WIFEXITED (status))
 		return (WEXITSTATUS (status));	/* return child's termination status */