Add SUM sysctl

[rank1seeker at gmail.com]

> On 15/04/2011, at 17:49, rank1seeker at gmail.com wrote:
> >> On 15/04/2011, at 17:03, rank1seeker at gmail.com wrote:
> >>> I would like implementation of boolean sysctl var, that would show, 
is 
> > system in a single user mode.
> >>> I would like it from 8.3 onwards.
> >> 
> >> AFAIK the kernel doesn't have a "single user" mode.
> >> 
> >> It's just that when you boot into single user mode it asks you want to 
> > run rather than starting /sbin/init.
> > 
> > I see, but 'ps' shows /sbin/init as PID 1, in both SUM and MUM.
> > How can I fiducially ensure that I am in SUM.
> > On what to rely/look on.
> 
> Oh oops, I guess the kernel runs init -s which then asks you..

So, what is solution?
Currently I need to mess with lookup, in env variables.

It must cover cases of rebooting into SUM and drop from MUM (# shutdown 
now) in SUM.