Enormous utmp since mpsafetty
Gary Jennejohn
gary.jennejohn at freenet.de
Wed Aug 27 14:19:42 UTC 2008
On Wed, 27 Aug 2008 12:50:17 +0100 (BST)
Robert Watson <rwatson at FreeBSD.org> wrote:
> On Wed, 27 Aug 2008, Ollivier Robert wrote:
>
> > According to Gary Jennejohn:
> >> There are many more pseudo-ttys in /etc/ttys now. AFAIK utmp allocates an
> >> entry for every one of them at startup.
> >
> > utmp concepts are ancient. It is indexed by the tty/pty number so can grow
> > rather large but it should be a sparse one too. I remember talks about
> > replacing it with something a bit more modern. Backward compatibility is
> > assured through login(3) although it would break programs digging in the
> > utmp file itself. SVR4 had utmp/utmpx and setutline/getutline BTW...
>
> Right -- utmp growing to 256K would be an excellent example of utmp format
> inefficiency. On the other hand, utmp growing to 998M is probably an example
> of a bug rather than an inefficient design. freefall.FreeBSD.org, a
> relatively busy shell box, has a utmp of around 5k, so common use doesn't
> generally exercise that inefficiency...
>
But freefall is running FreeBSD 7.0-STABLE #34: Sat Apr 12, so it doesn't
have the new tty stuff running, although I don't suppose that completely
explains the gigantic utmp which OT reported.
---
Gary Jennejohn
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