From owner-freebsd-emulation@FreeBSD.ORG Thu May 1 08:18:51 2008 Return-Path: Delivered-To: freebsd-emulation@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id DDEC2106564A for ; Thu, 1 May 2008 08:18:51 +0000 (UTC) (envelope-from rdivacky@vlk.vlakno.cz) Received: from vlakno.cz (vlk.vlakno.cz [62.168.28.247]) by mx1.freebsd.org (Postfix) with ESMTP id 899ED8FC21 for ; Thu, 1 May 2008 08:18:51 +0000 (UTC) (envelope-from rdivacky@vlk.vlakno.cz) Received: from localhost (localhost [127.0.0.1]) by vlakno.cz (Postfix) with ESMTP id 9EC9F67D5CF; Thu, 1 May 2008 10:18:22 +0200 (CEST) X-Virus-Scanned: amavisd-new at vlakno.cz Received: from vlakno.cz ([127.0.0.1]) by localhost (vlk.vlakno.cz [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id K-x-W-RfKR18; Thu, 1 May 2008 10:18:11 +0200 (CEST) Received: from vlk.vlakno.cz (localhost [127.0.0.1]) by vlakno.cz (Postfix) with ESMTP id 631A867D5CD; Thu, 1 May 2008 10:18:11 +0200 (CEST) Received: (from rdivacky@localhost) by vlk.vlakno.cz (8.14.2/8.14.2/Submit) id m418IBwA055475; Thu, 1 May 2008 10:18:11 +0200 (CEST) (envelope-from rdivacky) Date: Thu, 1 May 2008 10:18:11 +0200 From: Roman Divacky To: Pieter de Boer Message-ID: <20080501081811.GB54624@freebsd.org> References: <481897AB.7070003@thedarkside.nl> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <481897AB.7070003@thedarkside.nl> User-Agent: Mutt/1.4.2.3i Cc: freebsd-emulation@freebsd.org Subject: Re: Linux compat ioctl return values X-BeenThere: freebsd-emulation@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Development of Emulators of other operating systems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 01 May 2008 08:18:51 -0000 On Wed, Apr 30, 2008 at 06:00:43PM +0200, Pieter de Boer wrote: > Hi, > > I've been working on a kernel driver that creates a device. This device > in turn is opened and ioctl'd from a Linux executable. I've registered a > handler for these ioctl's and my ioctl handler is succesfully executed. > > My ioctl-handler returns a large positive value, but the userland > application retrieves the value 1, EPERM. If I return 42, the userland > application retrieves 42, but 260 is retrieved as 1. It appears there's a > threshold somewhere above which the return value is set to 1, but I > haven't been able to find out where in the code this is done. The Linux > executable actually expects the value I return, and doesn't work when > EPERM is found instead. > > So, the question is: does anyone know where such a threshold may > reside and how to work around it? this is done in (for i386) sys/i386/i386/trap.c around line 1050. in short, we define in the sysvec structure sv_errtbl and if returned error > the size of the table we just return -1. error table for linux is roughly to 70. thats why you are getting -1 (1 after translation) you might extend the errno table (i386/linux/linux_sysvec.c for i386, line 126) if you provide (tested!) patch for i386/amd64, I am sure it will get commited roman