Update ntp.pm

[cedr-x]

offset with a negative "-1 second" output cause a critical status of the plugin. Offsets should be positive integers

Community contributors

Description

Sometimes, centreon_linux_snmp.pl --plugin=os::linux::snmp::plugin --mode=time trigger critical status when the checked host is just a second behind the ref_time

sudo -u centreon-engine /usr/lib/centreon/plugins//centreon_linux_snmp.pl --plugin=os::linux::snmp::plugin --mode=time --hostname=192.168.1.118 --snmp-version=2c --snmp-community=****** --warning-offset=120 --critical-offset=300 
CRITICAL: Time offset -1 second(s): Local Time : 2025-12-01T09:42:30 (Europe/Paris) | 'offset'=-1s;0:120;0:300;;

Type of change

• Patch fixing an issue (non-breaking change)

How this pull request can be tested ?

Check against an host which have it clock set near 1s behing ntp ref time
The unpatched check is tossed be criticals when it retrives exactly "-1" (second) as offset
This patched check, returning in that case "1" stay with status OK

tested with:

sudo -u centreon-engine /usr/lib/centreon/plugins//centreon_linux_snmp.pl --plugin=os::linux::snmp::plugin --mode=time --hostname=192.168.1.118 --snmp-version=2c --snmp-community=****** --warning-offset=120 --critical-offset=300 
OK: Time offset 1 second(s): Local Time : 2025-12-01T09:51:12 (+0100) | 'offset'=1s;0:120;0:300;;

Checklist

• I have followed the coding style guidelines provided by Centreon
• I have commented my code, especially hard-to-understand areas of the PR.
• I have rebased my development branch on the base branch (develop).
• I have provide data or shown output displaying the result of this code in the plugin area concerned.

[omercier]

Hi @cedr-x,
Thanks for your contribution, but I think losing the minus signs would mean that you don't know if your host is ahead or late compared to the reference time.

Here's what I suggest:

• Use Nagios ranges: setting the thresholds this way --warning-offset=-120:120 will return a warning status only when the value is outside the interval [-120:120]. More information here. You can use this option without changing the code.
• Smart guessing the user's intentions: instead of transforming the threshold into its absolute value, suppose that if the threshold value is a positive integer, then the user probably meant "I want the offset's absolute value to be less than x", and silently change the threshold from n to -n:n.

What do you think?