Xref: utzoo comp.bugs.sys5:1006 comp.unix.wizards:16815
Path: utzoo!attcan!telly!eci386!clewis
From: clewis@eci386.uucp (Chris Lewis)
Newsgroups: comp.bugs.sys5,comp.unix.wizards
Subject: Re: ULIMIT adjustment in System V kernel creation
Keywords: sysv, ulimit, filesystem
Message-ID: <1989Jun9.142904.1778@eci386.uucp>
Date: 9 Jun 89 14:29:04 GMT
References: <252@chip.UUCP>
Reply-To: clewis@eci386.UUCP (Chris Lewis)
Organization: R. H. Lathwell Associates: Elegant Communications, Inc.
Lines: 53

In article <252@chip.UUCP> mparker@chip.UUCP (M. D. Parker) writes:
>Under the current System V R3 flavor of operating system I am using,
>our ULIMIT is gened up to max value.  

Oh you lucky sod!  This is how it *should* be - makes everything else
so simple...

>In otherwords, there is no restriction.
>While I like that approach, I do want to limit the value locally since we
>have had an occaion where one person ran us out of user disk space.  My
>preference is to change this in the kernel.  Initial examinations of what
>I have received do not point to which parameter to change.  Anybody know?

>Yes, I do know that I could put a wrapper around /etc/init to do this but
>I'd really like to at least know about the kernel modification.

Remember that you can adjust the ulimit *down* without root privilege...

Put in your /etc/profile:

if [ $LOGNAME = <users you wish to restrict> ]
then
    ulimit <whatever you wish - as long as it's *downwards*>
fi

Or, get fancy and do something like:

	ul=`sed -n -e '/^$LOGNAME[ <tab>]/s/^.*[ <tab>][ <tab>]*//p' 
	    /etc/ulimitsperuser`
	if [ -n "$ul" ]
	then
	    ulimit $ul
	fi
[/etc/ulimitsperuser consists of tab separated username, ulimit value
pairs, one pair per line]

remember: 
	- the user's shell runs /etc/profile and any shell settings/
	  ulimit etc persist for that user.
	- *any* user can lower ulimit for themselves, but only root can 
	  raise it

[Aside: it's too bad in a way that the shell you get doesn't run effective
id == 0 during execution of /etc/profile, and undoes this just before
executing your personal profile - would make upping ulimit or other similar
things easy to do on a per-user basis, though it would require some 
co-operation from /etc/login and probably an explicit shell builtin to change
the effective userid back to the real]
-- 
Chris Lewis, R.H. Lathwell & Associates: Elegant Communications Inc.
UUCP: {uunet!mnetor, utcsri!utzoo}!lsuc!eci386!clewis
Phone: (416)-595-5425