4.2 oddity -- SLOGIN flag in proc.h

[Jeff Glass]

In article <607 at brl-tgr.ARPA> scc%computer-lab.cambridge.ac.uk at ucl-cs.arpa (Stephen Crawley) writes:
> The <sys/proc.h> header file contains the following line :-
> 
> #define	SLOGIN	0x0800000	/* a login process (legit child of init) */
> 
> However, ps -axl indicates that this bit is not set for any processes.
> Indeed, grepping /sys/sys confirmed that SLOGIN isn't referenced anywhere.
> While making sure that the flag gets set would seem to be straight forward,
> I'm not convinced that it would be stunningly useful.  [ What would be
> more useful would be if the login shell pid were recorded in /etc/utmp! ]

I think this method would be superior to the way that {c,}sh now find that
they are login shells (checking if argv[0][0] == '-').  at least one security
hole takes advantage of this.

I also think Stephen's suggestion (putting the pid in utmp) is pretty neat.

/jeff
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