Title: Fixing possible logging issues when using datasource programs for monitoring
Level: 1
Component: core
Compatible: compat
Version: 1.2.8b5
Date: 1457703007
Class: fix

When calling datasource programs for monitoring they are executed as subprocesses
of Check_MK. Check_MK as passing all filedescriptors except stdout and stderr to
the subprocess. So if a subprocess was doing something strange with them it could
happen that this influenced the handling within Check_MK.

This could, for example, confuse the communication between the CMC and the Check_MK
keepalive helper processes.
