From owner-freebsd-hackers Mon Aug 12 11:01:53 1996 Return-Path: owner-hackers Received: (from root@localhost) by freefall.freebsd.org (8.7.5/8.7.3) id LAA02678 for hackers-outgoing; Mon, 12 Aug 1996 11:01:53 -0700 (PDT) Received: from pdx1.world.net (pdx1.world.net [192.243.32.18]) by freefall.freebsd.org (8.7.5/8.7.3) with ESMTP id LAA02669 for ; Mon, 12 Aug 1996 11:01:50 -0700 (PDT) Received: from suburbia.net (suburbia.net [203.4.184.1]) by pdx1.world.net (8.7.5/8.7.3) with ESMTP id LAA03040; Mon, 12 Aug 1996 11:03:15 -0700 (PDT) Received: (proff@localhost) by suburbia.net (8.7.4/Proff-950810) id EAA29489; Tue, 13 Aug 1996 04:00:42 +1000 From: Julian Assange Message-Id: <199608121800.EAA29489@suburbia.net> Subject: Re: mmap #2 To: mrcpu@cdsnet.net (Jaye Mathisen) Date: Tue, 13 Aug 1996 04:00:41 +1000 (EST) Cc: joerg_wunsch@uriah.heep.sax.de, freebsd-hackers@FreeBSD.ORG, proff@suburbia.net In-Reply-To: from "Jaye Mathisen" at Aug 12, 96 10:42:14 am X-Mailer: ELM [version 2.4 PL23] Content-Type: text Sender: owner-hackers@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk > > > I think it was the other way around, it was truncating a mmap'd file. > > Specifically, I had problems when the active file shrunk after an rmgroup, > then I would get weird behaviour. John said he saw where that could > potentially be problematic, but I never saw any fixes run by that > addressed it by name. Hmm. I only test behavior in the first block. There are a lot of complicated involvements that can happen when you play with the fd and the mmap at the same time. A number of mmap implimentations failed to do shared writes correctly, when "correctly" was defined opening a file, mmaping it, writing something to the mmaped region, lseek()ing back to offset 0, and then using read() to fetch data. -- "Of all tyrannies a tyranny sincerely exercised for the good of its victims may be the most oppressive. It may be better to live under robber barons than under omnipotent moral busybodies, The robber baron's cruelty may sometimes sleep, his cupidity may at some point be satiated; but those who torment us for own good will torment us without end, for they do so with the approval of their own conscience." - C.S. Lewis, _God in the Dock_ +---------------------+--------------------+----------------------------------+ |Julian Assange RSO | PO Box 2031 BARKER | Secret Analytic Guy Union | |proff@suburbia.net | VIC 3122 AUSTRALIA | finger for PGP key hash ID = | |proff@gnu.ai.mit.edu | FAX +61-3-98199066 | 0619737CCC143F6DEA73E27378933690 | +---------------------+--------------------+----------------------------------+