From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757058Ab0E2W7O (ORCPT ); Sat, 29 May 2010 18:59:14 -0400 Received: from zeniv.linux.org.uk ([195.92.253.2]:59464 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757142Ab0E2W7M (ORCPT ); Sat, 29 May 2010 18:59:12 -0400 Date: Sat, 29 May 2010 23:59:08 +0100 From: Al Viro To: Alan Cox Cc: Samo Pogacnik , linux-embedded , linux kernel , Randy Dunlap Subject: Re: [PATCH] detour TTY driver Message-ID: <20100529225908.GQ31073@ZenIV.linux.org.uk> References: <1273918658.2341.17.camel@itpsd6lap> <1275171436.2122.29.camel@itpsd6lap> <20100529235402.296406d9@lxorguk.ukuu.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100529235402.296406d9@lxorguk.ukuu.org.uk> User-Agent: Mutt/1.5.20 (2009-08-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, May 29, 2010 at 11:54:02PM +0100, Alan Cox wrote: > > + /* 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); That alone is enough for a NAK. Do Not Do That. Fake struct file/dentry/inode and their uses are not acceptable. Neither is modifying file_operations, while we are at it.