[Pkg-nagios-devel] Bug#895558: monitoring-plugins-basic: check_ping cannot be used with puny-code domains

[Uwe Kleine-König]

On Thu, Apr 12, 2018 at 05:43:03PM +0200, Uwe Kleine-König wrote:
> Package: monitoring-plugins-basic
> Version: 2.2-3
> Severity: normal
> 
> Hello,
> 
> I want to monitor a host called www.xn--kleine-knig-yfb.de (or
> www.kleine-könig.de). Both ways to write this hostname are incompatible with
> check_ping:
> 
> 	$ /usr/lib/nagios/plugins/check_ping -H www.xn--kleine-knig-yfb.de -w 5,5% -c 10,10% -vvv
> 	CMD: /bin/ping6 -n -U -w 10 -c 5 www.xn--kleine-knig-yfb.de
> 	Got stderr: ping: www.xn--kleine-knig-yfb.de: Parameter string not correctly encoded
> 	/bin/ping6 -n -U -w 10 -c 5 www.xn--kleine-knig-yfb.de
> 	CRITICAL - Could not interpret output from ping command
> 
> 	$ /usr/lib/nagios/plugins/check_ping -H www.kleine-könig.de -w 5,5% -c 10,10% -vvv
> 	check_ping: Invalid hostname/address - www.kleine-könig.de
> 	Usage:
> 	check_ping -H <host_address> -w <wrta>,<wpl>% -c <crta>,<cpl>%
> 	 [-p packets] [-t timeout] [-4|-6]
> 
> "funny" enough, ping6 supports both variants:
> 
> 	$ /bin/ping6 -n -U -w 10 -c 5 www.xn--kleine-knig-yfb.de
> 	PING www.xn--kleine-knig-yfb.de(2a01:4f8:c0c:3a97::2) 56 data bytes
> 	64 bytes from 2a01:4f8:c0c:3a97::2: icmp_seq=1 ttl=64 time=0.092 ms
> 	64 bytes from 2a01:4f8:c0c:3a97::2: icmp_seq=2 ttl=64 time=0.039 ms
> 	64 bytes from 2a01:4f8:c0c:3a97::2: icmp_seq=3 ttl=64 time=0.068 ms
> 	64 bytes from 2a01:4f8:c0c:3a97::2: icmp_seq=4 ttl=64 time=0.046 ms
> 	64 bytes from 2a01:4f8:c0c:3a97::2: icmp_seq=5 ttl=64 time=0.061 ms
> 
> 	--- www.xn--kleine-knig-yfb.de ping statistics ---
> 	5 packets transmitted, 5 received, 0% packet loss, time 4092ms
> 	rtt min/avg/max/mdev = 0.039/0.061/0.092/0.019 ms

I looked at the code for a while, and the culprit for
www.xn--kleine-knig-yfb.de not working is that spopen() (in
plugins/popen.c) does LC_ALL=C:

	$ env LC_ALL=C /bin/ping6 -n -U -w 10 -c 5 www.xn--kleine-knig-yfb.de
	ping: www.xn--kleine-knig-yfb.de: Parameter string not correctly encoded

And with LC_ALL=C it's also not surprising that the domain with ö
doesn't work.

So the obvious ways to fix the problem are:

 - let spopen() use C.UTF-8
 - fix ping to be able to work with www.xn--kleine-knig-yfb.de even with
   LC_ALL=C .

I'll open a bug against iputils-ping for the latter assuming people fear
to switch away from 7-bit ascii.

Best regards
Uwe
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