[PATCH v2] /proc/pid/status: show all sets of pid according to ns

[Vasily Kulikov]

On Wed, May 28, 2014 at 16:44 +0400, Pavel Emelyanov wrote:
> On 05/28/2014 02:24 PM, Chen Hanxiao wrote:
> > We need a direct method of getting the pid inside containers.
> 
> But there's more generic issue -- some day we'll need to know not only
> PIDs as seen from different namespaces, but also SIDs and PGIDs.

Maybe include all per-ns ID in a separate file?  Then the old 'status'
file includes IDs from the current namespace only, the new file (e.g.
'ids' or 'ns_ids') contains only hierarchical IDs which differ from
namespace to namespace for all possible namespaces.  It will be simplier
to parse the file -- if 'ns_ids' file contains some ID then this ID for
every ns can be obtained regardless of the specific ID name (SID, PID,
PGID, etc.).

> 
> > If some issues occurred inside container guest, host user
> > could not know which process is in trouble just by guest pid:
> > the users of container guest only knew the pid inside containers.
> > This will bring obstacle for trouble shooting.
> > 
> > This patch adds two fields:
> > 
> > NStgid and NSpid.
> > 
> > a) In init_pid_ns, nothing changed;
> > 
> > b) In one pidns, will tell the pid inside containers:
> > NStgid:	1628 	9 	3
> > NSpid:	1628 	9 	3
> > ** Process id is 1628 in level 0, 9 in level 1, 3 in level 2.
> > 
> > c) If pidns is nested, it depends on which pidns are you in.
> > NStgid:	9 	3
> > NSpid:	9 	3
> > ** Views from level 1

Thanks,

-- 
Vasily Kulikov
http://www.openwall.com - bringing security into open computing environments