[Nagiosplug-devel] [ nagiosplug-Bugs-1469472 ] check_ping dns lookup problem

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Bugs item #1469472, was opened at 2006-04-12 15:42
Message generated for change (Comment added) made by atxformfactor
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Category: General plugin execution
Group: Release (specify)
Status: Open
Resolution: None
Priority: 5
Submitted By: nsturm (nsturm)
Assigned to: Nobody/Anonymous (nobody)
Summary: check_ping dns lookup problem

Initial Comment:
This is on 1.4.2.

check_ping and maybe other plugins, first set their
SIGARLM timeout and then do an unconditional dns lookup
on the address provided, even if it is an IP.

Besides the dns lookup on the IP address is useless to
the best of my knowledge, it can timeout, which the code
does not handle.

If the dns lookup does time out, fileno(child_process)
in popen_timeout_alarm_handler() will segfault.

A simple workaround, which is BAD BAD BAD, is attached.
The proper solution would be to rewrite this piece of
code (and similar ones on other modules) to correctly
deal with the dns timeout.

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Comment By: Mark Hennessy (atxformfactor)
Date: 2006-07-12 14:56

Message:
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Why hasn't anyone picked this one up?
I have noticed this issue as well.

I get this message when DNS doesn't work due to a name
server connection issue on the machine performing the Nagios
checks:
popen timeout received, but no child process

All of my host entries are by IP, I don't see why check_ping
should need to look up DNS for IPs at all.  Someone should
at least add a commandline switch or something.  I may just
have to write a perl wrapper for my local system's ping if
nothing is done by anyone about this. :(

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