From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261535AbVFIPMd (ORCPT ); Thu, 9 Jun 2005 11:12:33 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261830AbVFIPMd (ORCPT ); Thu, 9 Jun 2005 11:12:33 -0400 Received: from caramon.arm.linux.org.uk ([212.18.232.186]:11788 "EHLO caramon.arm.linux.org.uk") by vger.kernel.org with ESMTP id S261535AbVFIPMa (ORCPT ); Thu, 9 Jun 2005 11:12:30 -0400 Date: Thu, 9 Jun 2005 16:12:25 +0100 From: Russell King To: moreau francis Cc: Frederik Deweerdt , linux-kernel@vger.kernel.org Subject: Re: [TTY] exclusive mode question Message-ID: <20050609161225.A14513@flint.arm.linux.org.uk> Mail-Followup-To: moreau francis , Frederik Deweerdt , linux-kernel@vger.kernel.org References: <20050609121638.GD507@gilgamesh.home.res> <20050609142250.80926.qmail@web25804.mail.ukl.yahoo.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit User-Agent: Mutt/1.2.5.1i In-Reply-To: <20050609142250.80926.qmail@web25804.mail.ukl.yahoo.com>; from francis_moreau2000@yahoo.fr on Thu, Jun 09, 2005 at 04:22:49PM +0200 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 09, 2005 at 04:22:49PM +0200, moreau francis wrote: > --- Frederik Deweerdt a écrit : > > Le 09/06/05 13:41 +0200, moreau francis écrivit: > > > > > > oh ok...sorry I misunderstood TIOEXCL meaning ;) > > > Do you know how I could implement such exclusive mode (the one I described) > > ? > > > > > This is handled through lock files, google for LCK..ttyS0 > > > > This lock mechanism is a convention but nothing prevent a user application to > issue a "echo foo > /dev/ttyS0" command while "LCK..ttyS0" file exists... Which is absolutely necessary to work if you think about an application like minicom and its file transfer helpers, which may need to re-open the serial port. TTY locking is done via lock files only, and all non-helper applications must coordinate their access via the lock files. There is no other mechanism. -- Russell King Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ maintainer of: 2.6 Serial core