From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758718Ab0KROme (ORCPT ); Thu, 18 Nov 2010 09:42:34 -0500 Received: from earthlight.etchedpixels.co.uk ([81.2.110.250]:58846 "EHLO www.etchedpixels.co.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1758685Ab0KROmd (ORCPT ); Thu, 18 Nov 2010 09:42:33 -0500 Date: Thu, 18 Nov 2010 14:41:23 +0000 From: Alan Cox To: "Dr. Werner Fink" Cc: Greg KH , Lennart Poettering , Kay Sievers , Valdis.Kletnieks@vt.edu, linux-kernel , Randy Dunlap , Jiri Slaby Subject: Re: tty: add 'active' sysfs attribute to tty0 and console device Message-ID: <20101118144123.5417ccbd@lxorguk.ukuu.org.uk> In-Reply-To: <20101118131420.GA23872@boole.suse.de> References: <25482.1290031268@localhost> <20101117235647.00766e32@lxorguk.ukuu.org.uk> <20101118012734.GA8558@kroah.com> <20101118014848.GA7873@tango.0pointer.de> <20101118015310.GA30480@kroah.com> <20101118110020.GA13871@boole.suse.de> <20101118112335.434de53a@lxorguk.ukuu.org.uk> <20101118121256.GA19884@boole.suse.de> <20101118125822.16718289@lxorguk.ukuu.org.uk> <20101118131420.GA23872@boole.suse.de> X-Mailer: Claws Mail 3.7.6 (GTK+ 2.18.9; x86_64-redhat-linux-gnu) Face: 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 Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > How can I detect the major and minor of the primary console device > of /dev/console without controlling tty? Even if my old blogd In the general case you can't - because a console may not have a tty. Quite a few don't. For the cases where one has a device I can't see a clean way to do it as an fstat on the console device will give you the console major/mninor and some code depends upon that. The iniability to get it is clearly a flaw and you need the sysfs link or a sysfs list of consoles (again remembering many of them won't have a tty bound). > and the bootlogd(8) of SysInitV using TIOCCONS are outdated by SystemD > the question before doing the TIOCCONS is which is the primary console > device to e.g. create the device node in initrd or for bootlogd(8) > to write a copy of the console messages back to the original > primary console (and the other console devices). For init it is /dev/console as opened at boot time and passed to the initial user init task but with no nice way to work back to a device node. Incidentally the primary console (as in printk) can be accessed as a tty via the ttyprintk driver which got added recently because embedded people wanted to use the printk interface as a (write only) tty console as well.