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

[Andreas Ericsson]

Dag Wieers wrote:
> On Fri, 2 Sep 2005, sean finney wrote:
> 
> 
>>now, a question about this patch...
>>
>>the code in question:
>>
>>==
>>    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 */
>>
>>>    return (1);
>>
>>==
>>
>>does this remove the check for the child's exit status?
> 
> 
> The patch is not mine, but I think you are correct. It probably should be 
> something like:
> 
> 	while (waitpid (pid, &status, 0) < 0) {
> 
> 		switch(errno) {
> 			case ECHILD: break;		/* Child has already exited */


This is a never-ending loop. If we get ECHILD once, we'll get it every time.

> 			case EINTR: break;		/* Interrupted function call */
> 			case default: return 1;


This is bad, because all commands that exit successfully will return 1 
and thus issue a warning.

> 		}
> 
> 	}
> 

Below this point is never reached.

> 	if (WIFEXITED (status))
> 		return (WEXITSTATUS (status));  /* return child's termination status */
> 
> 	return 1;
> 

I've revamped the runcmd thingie and it's been running stable for a 
couple of months, so it's ready for implementation. CVS commit access or 
a couple of hours with Sean and it'll be available for download in a 
jiffy. A snapshot is already available at http://oss.op5.se/nagios/ 
although that snapshot has a bug in check_load.c when neither 
/proc/loadavg or getloadavg() is available (which is inherited from the 
official distro, but still).

-- 
Andreas Ericsson                   andreas.ericsson at op5.se
OP5 AB                             www.op5.se
Lead Developer