ULIMIT adjustment in System V kernel creation

Ric Urrutia ric at Apple.COM
Wed Jun 14 08:44:46 AEST 1989


In article <1989Jun9.142904.1778 at eci386.uucp> clewis at eci386.UUCP (Chris Lewis) writes:
>In article <252 at chip.UUCP> mparker at 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...
>
>
>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


Another way of doing it would be to write a c program that sets ulimit
to some value and then exec's /etc/getty.  You could call it something
like ungetty and pass it an argument (whatever ulimit you wanted).  Then
you could simply replace the getty entries in /etc/inittab with the 
name of your new program.  This seems a lot cleaner and you can set the
ulimit to whatever you want per tty.



More information about the Comp.unix.wizards mailing list