From owner-freebsd-current Wed Jun 19 13:44:05 1996 Return-Path: owner-current Received: (from root@localhost) by freefall.freebsd.org (8.7.5/8.7.3) id NAA19009 for current-outgoing; Wed, 19 Jun 1996 13:44:05 -0700 (PDT) Received: from jraynard.demon.co.uk (jraynard.demon.co.uk [158.152.42.77]) by freefall.freebsd.org (8.7.5/8.7.3) with ESMTP id NAA18761 for ; Wed, 19 Jun 1996 13:42:54 -0700 (PDT) Received: (from fcurrent@localhost) by jraynard.demon.co.uk (8.7.5/8.6.12) id KAA12951; Wed, 19 Jun 1996 10:18:16 GMT Date: Wed, 19 Jun 1996 10:18:16 GMT Message-Id: <199606191018.KAA12951@jraynard.demon.co.uk> From: James Raynard To: wosch@cs.tu-berlin.de CC: freebsd-current@freebsd.org In-reply-to: <199606190007.CAA01478@campa.panke.de> (message from Wolfram Schneider on Wed, 19 Jun 1996 02:07:42 +0200) Subject: Re: ktrace [Was: 2.2-960612-SNAP resolver problems] Sender: owner-current@freebsd.org X-Loop: FreeBSD.org Precedence: bulk > >Indeed. Apart from volume of output, is there any particular reason > >why ktrace writes to a file which kdump reads in, as opposed to using > >a pipe? Particularly as the first thing kdump does is > >freopen(tracefile, "r", stdin)! > > Hm, try `ktrace -f /dev/stdout | kdump -f /dev/stdin' $ ktrace -f /dev/stdout -p 12922 | kdump -f /dev/stdin ktrace: /dev/stdout: Operation not supported by device. I did actually try this before I posted, although with /dev/fd/[01]. The problem is that ktrace doesn't actually write to the file itself, it passes the name of the file to a system call that does kernel writes to the vnode, and this only seems to work for regular files. -- James Raynard, Edinburgh, Scotland james@jraynard.demon.co.uk