From owner-freebsd-stable@FreeBSD.ORG Mon Oct 13 05:16:39 2008 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 7F1EC106568A for ; Mon, 13 Oct 2008 05:16:39 +0000 (UTC) (envelope-from unixmania@gmail.com) Received: from fk-out-0910.google.com (fk-out-0910.google.com [209.85.128.191]) by mx1.freebsd.org (Postfix) with ESMTP id 007F08FC22 for ; Mon, 13 Oct 2008 05:16:38 +0000 (UTC) (envelope-from unixmania@gmail.com) Received: by fk-out-0910.google.com with SMTP id k31so1618565fkk.11 for ; Sun, 12 Oct 2008 22:16:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from:to :subject:cc:in-reply-to:mime-version:content-type :content-transfer-encoding:content-disposition:references; bh=vMVds9CiPSRAfzaAwn5vYbuUOBNcrtXQe+7Y857n6sQ=; b=Srj+kCZo3kLyXKIVJGRy36RZ044KsK2kE/js6rsGDABTFqHQo4recWtCcUE46dU/B7 edwUMhSODLdmuJT/dYp/+j6B3TDpOLEdbA8EaD2G7OFfbD3KKvGxz4e6KBZqcp05sqvm Z/GuFv+B8xXIsQAfFsXEt2dbh6p8IfB03qk3o= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:cc:in-reply-to:mime-version :content-type:content-transfer-encoding:content-disposition :references; b=srT/4aFfzbLmGTsIoy45TUKhzMkcbu4IjNttsGeRHJeOw3CPaDYEGfMZFBGGIEN3Il 29WtPCkvOf6dIAd3puBKFyqwbdto8WtlpzKO6yLQFwGkEc++pjh1daYSprIymHdyHmuS IESMuOIZtEBu81eEER7aL1RkcHRXlwic5+HuM= Received: by 10.103.137.19 with SMTP id p19mr3213712mun.108.1223874997130; Sun, 12 Oct 2008 22:16:37 -0700 (PDT) Received: by 10.103.231.14 with HTTP; Sun, 12 Oct 2008 22:16:37 -0700 (PDT) Message-ID: Date: Mon, 13 Oct 2008 03:16:37 -0200 From: "Carlos A. M. dos Santos" To: "Jeff Blank" In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <20080910203445.GA8561@mr-happy.com> Cc: freebsd-stable@freebsd.org Subject: Re: can't see non-root writes to /dev/console X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 13 Oct 2008 05:16:39 -0000 On Wed, Sep 10, 2008 at 11:54 PM, Carlos A. M. dos Santos wrote: > On Wed, Sep 10, 2008 at 5:34 PM, Jeff Blank wrote: >> I just upgraded a RELENG_7 (amd64) box from 20080714 to "latest" >> (which seems to be from a few days ago--no changes from Monday >> morning's csup to today's) and can no longer see the effect of writing >> to /dev/console as non-root. When I log in using xdm, my user owns >> /dev/console, mode 0622 (-rw--w--w-), and I start an 'xterm -C'. But >> when I, for example, >> >> echo foo > /dev/console >> >> I see nothing in the console xterm. No error messages, and echo exits >> 0. If I su to root and do the same, I get 'foo' in the same console >> xterm. Syslog messages to /dev/console also appear, of course. All >> the above applies to xconsole as well, not just xterm. I did >> recompile xterm from 20080616 ports, but it didn't fix the issue >> (didn't expect it to, as xterm clearly has no trouble attaching and >> reading). So my echo is getting lost in the kernel, I guess. >> >> Known problem? Intentional change? Something else? > > I have seen this problem since 6.x times and still on 7.x. I also > noticed that if I send something to the console after xconsole starts > then I can sned messages as an ordinary user. My workaround was > modifying the Xsetup_0 script (I used xdm for login), adding a line > with > > (sleep 3; date >> "$dev_console") & > > just after starting xconsole. > > I didn't have time to set up a machine with 8-CURRENT yet, so I could > not check if the new mp-safe tty implementation fixes this, either > intentionally or by a fortunate side effect. I took some time to look at this again. I'm using 8.0-CURRENT now (GENERIC kernel), csup'ed and compiled yesterday. Xconsole is unable to open the console even if my user & group own /dev/console and the permissions are set to 0622. This happens because of the following code in xconsole.c: 289 int on = 1; 290 if (ioctl (tty_fd, TIOCCONS, (char *) &on) != -1) 291 input = fdopen (pty_fd, "r"); The ioctl call fails (EPERM) because only superuser can use TIOCCONS, regardless the ownership of the device. Using xterm with the "-C" argument works because xterm is installed with the setuid flag bit on. So the solution is "chmod +us xconsole". -- cd /usr/ports/sysutils/life make clean