[Devel] Re: task_session() and task->signal->session

[Sukadev Bhattiprolu]

Thanks. 

Eric W. Biederman [ebiederm at xmission.com] wrote:
| Sukadev Bhattiprolu <sukadev at us.ibm.com> writes:
| 
| > I am trying to understand the diff between task_session() and
| > task->signal-session and why we have the two notions of session.
| > Are we just phasing out one of them ?
| 
| Yes.

I guess we are phasing out task->signal->session.

| 
| > In general each process has a single session id. The only exception
| > being a process that unshares its pid ns. Such process will have
| > exactly two session ids, one for each pid ns. No ?
| 
| Each process has a single session.
| 
| That session can potentially have a different session id in each
| pid namespace.

both of us used the word "have" above. But do we actually store (in some
data structure) the multiple session ids ? Or will the following work:

	Each task refers to another task (possibly itself) as its session
	leader (we find this using task_session()).

	The session leader, like any other task, has multiple process ids,
	one in each namespace.

	So to find the session id of a task, we find its session leader
	and find the appropriate process id of the session leader

	i.e we don't actually store the multiple sids a task

| 
| So for internal tests we want to compare the struct pid pointers
| instead of the numbers visible to user space.
| 
| Eric
_______________________________________________
Containers mailing list
Containers at lists.osdl.org
https://lists.osdl.org/mailman/listinfo/containers