Date: Wed, 27 Aug 2008 12:50:17 +0100 (BST) From: Robert Watson <rwatson@FreeBSD.org> To: Ollivier Robert <roberto@keltia.freenix.fr> Cc: freebsd-current@freebsd.org Subject: Re: Enormous utmp since mpsafetty Message-ID: <alpine.BSF.1.10.0808271248200.96701@fledge.watson.org> In-Reply-To: <20080827114623.GA52927@keltia.freenix.fr> References: <20080826124335.GD3305@carrot.paeps.cx> <48B416E7.70905@163.com> <20080827091255.GH3305@carrot.paeps.cx> <20080827132141.593e728d@peedub.jennejohn.org> <20080827114623.GA52927@keltia.freenix.fr>
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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... Robert N M Watson Computer Laboratory University of Cambridge > > cf. sessreg(1) > > System V has a better interface to utmp than BSD; it dynamically allo- > cates entries in the file, instead of writing them at fixed positions > indexed by position in /etc/ttys. > > -- > Ollivier ROBERT -=- FreeBSD: The Power to Serve! -=- roberto@keltia.freenix.fr > Darwin sidhe.keltia.net Version 9.2.0: Tue Feb 5 16:13:22 PST 2008; i386 > > _______________________________________________ > freebsd-current@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-current > To unsubscribe, send any mail to "freebsd-current-unsubscribe@freebsd.org" >
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