From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756845Ab0E2XdI (ORCPT ); Sat, 29 May 2010 19:33:08 -0400 Received: from t21.t-2.net ([84.255.209.100]:39118 "EHLO t21.t-2.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756161Ab0E2XdG (ORCPT ); Sat, 29 May 2010 19:33:06 -0400 Subject: Re: [PATCH] detour TTY driver From: Samo Pogacnik To: Alan Cox Cc: linux-embedded , linux kernel , Randy Dunlap , Al Viro In-Reply-To: <20100529235402.296406d9@lxorguk.ukuu.org.uk> References: <1273918658.2341.17.camel@itpsd6lap> <1275171436.2122.29.camel@itpsd6lap> <20100529235402.296406d9@lxorguk.ukuu.org.uk> Content-Type: text/plain Date: Sun, 30 May 2010 01:33:03 +0200 Message-Id: <1275175983.2122.42.camel@itpsd6lap> Mime-Version: 1.0 X-Mailer: Evolution 2.26.3 (2.26.3-1.fc11) Content-Transfer-Encoding: 7bit X-SGG-UMAMSID: 20100529233304Z22116t21.t-2.net 1OIVWa-0005ki-KS X-SGG-RESULT: 20100529233304Z22116t21.t-2.net C1:OK E1:OK MX1:OK BL:OK SPF:off CT:Unknown CM: SIP:84.255.254.67 SMF:samo_pogacnik@t-2.net Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > > +static void initial_console_redirect(void) > > +{ > > + long ret; > > + > > + /* re-register our fops write function */ > > + detour_fops.write = detour_write; > > + > > + detour_file.f_dentry = &detour_dentry; > > + detour_file.f_dentry->d_inode = &detour_inode; > > + detour_file.f_op = &detour_fops; > > + detour_file.f_mode |= FMODE_WRITE; > > + security_file_alloc(&detour_file); > > + INIT_LIST_HEAD(&detour_file.f_u.fu_list); > > + > > + detour_inode.i_rdev = MKDEV(TTYAUX_MAJOR, 3); > > + security_inode_alloc(&detour_inode); > > + INIT_LIST_HEAD(&detour_inode.inotify_watches); > > + > > + ret = detour_fops.open(&detour_inode, &detour_file); > > + printk(KERN_INFO "detour_fops.open() returned %ld\n", ret); > > + ret = detour_fops.unlocked_ioctl(&detour_file, TIOCCONS, 0); > > + printk(KERN_INFO "detour_fops.ioctl() returned %ld\n", ret); > > +} > > Bletch.. I'm really opposed to this kind of hackery. Fix your userspace a > tiny bit. > > So > - Write only tty that uses printk: Looks good to me, implementation > quibbles only > - Magic kernel hacks to shuffle things around in the initial console > logic - hideous. I still really think you need to fix your userspace > Thank you for all comments. I'll try to follow them (might take some time) and i'll remove the internal console redirection magic for sure. regards, Samo