PL286/external/ltp/testcases/kernel/containers/pidns

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PIDNS testcases Overview:

 A pid namespace is a view of particular set of tasks on the system. For processes, a process may have pid 1234 in one namespace, but have pid 1 in another.This allows processes to use process ids which are in use in other pid namespaces, without having to worry about what pids exist in other namespaces.

"A process has a pid in every ancestor pid namespaces up to the initial pid namespace.  If process B is in a child namespace relative to process A, then process A will see process B by the pid which is valid in process A's pid namespace."

"Another way of specifying process visibility, then is that process A will see all tasks which have a valid pid in process A's pid namespace."



Testcases:

1> Check the process id of container after cloning as 1.
2> After creation of container the PID Namespace of the container should have the parent group id as 1 and also session id as 1.
3> Create container: pass the parent namespacei id: mount /proc directory: check parent namespace id inside container: if it is exiting then PASS otherwise FAIL.

Check for PIDNS enablement: from 2.6.24 kernel version.