Detect Linux Runlevel

[Marko Rauhamaa]

Michael Torrie <torriem at gmail.com>:

> On 12/06/2016 03:29 PM, Marko Rauhamaa wrote:
>> Another thing is that, as stated before, the runlevel business is
>> legacy. It is still supported by systemd-update-utmp, but for how
>> long is anybody's guess.
>
> System V compatibility is still important to Linux, and as long as it
> is, something resembling a runlevel has to be provided, even it's just
> an abstraction of something else like a systemd target. So any system
> that advertises System V compliance or compatibility will have a
> runlevel.

I wonder if Linux still suffers from this local DoS:

	[ Now no-one else can log in ]

   This is a problem with advisory locking. The fact that anyone can
   create an exclusive lock on a file they can only read! Is this
   behavior appropriate?

   <URL: https://www.redhat.com/archives/linux-security/1996-Novembe
   r/msg00026.html>

Didn't try it, but the utmp API seems hopeless in this regard.


Marko