From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from list by lists.gnu.org with archive (Exim 4.71) id 1Z20tW-0004tQ-IT for mharc-grub-devel@gnu.org; Mon, 08 Jun 2015 13:31:30 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:44512) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Z20tT-0004rX-Ug for grub-devel@gnu.org; Mon, 08 Jun 2015 13:31:29 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Z20tP-0004qO-BU for grub-devel@gnu.org; Mon, 08 Jun 2015 13:31:27 -0400 Received: from mail-wi0-x233.google.com ([2a00:1450:400c:c05::233]:37690) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Z20tP-0004o9-5s for grub-devel@gnu.org; Mon, 08 Jun 2015 13:31:23 -0400 Received: by wifx6 with SMTP id x6so94538108wif.0 for ; Mon, 08 Jun 2015 10:31:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; bh=QS5lN8/t6+s3M79Jf8K5R6pXfzogyFp5sd7RmqC21eE=; b=tnzkufrICyB+7P9aBfeLc7CjLSflLFjBNkvHmjqyu6wv9IcDKuTXfOYHr/DCVIGiO7 IVWAeJabKBQy6BN9ERMRvsBa0bKgdUF02gWqPNVpl80CKHnOhJ6ETeFcdjkqXUbgPLIp OW6KC7x7vEoog6+0WrDoQZpuHoR7xp0MO+zLW2ede5rO2V+SFofRd5fnkjPqmbZqP5gb X6bqvH5K5NFGdAK96Sy7WeK4oTlLQgnB/X6U7fCC8arykMWls0/BkeZjomlm46430g+a gI9ngCa7LsoBQPAYaU/ooAX5DBS90V5Z8w/el7oWXAUovIRDXpsuNNYZTiHUDIWAQD5J stqQ== X-Received: by 10.180.102.74 with SMTP id fm10mr261086wib.25.1433784681985; Mon, 08 Jun 2015 10:31:21 -0700 (PDT) Received: from hobo (208.24.189.80.dyn.plus.net. [80.189.24.208]) by mx.google.com with ESMTPSA id fm8sm2076496wib.9.2015.06.08.10.31.20 (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Mon, 08 Jun 2015 10:31:21 -0700 (PDT) Date: Mon, 8 Jun 2015 18:31:06 +0100 From: Ross Lagerwall To: Andrei Borzenkov Subject: Re: [PATCH] core/partmap: Add El Torito boot catalog parsing Message-ID: <20150608173106.GA9456@hobo.lan> References: <1433672686-774-1-git-send-email-rosslagerwall@gmail.com> <20150608195144.69ed708c@opensuse.site> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="XsQoSWH+UP9D9v3l" Content-Disposition: inline In-Reply-To: <20150608195144.69ed708c@opensuse.site> User-Agent: Mutt/1.5.23 (2014-03-12) X-detected-operating-system: by eggs.gnu.org: Error: Malformed IPv6 address (bad octet value). X-Received-From: 2a00:1450:400c:c05::233 Cc: grub-devel@gnu.org X-BeenThere: grub-devel@gnu.org X-Mailman-Version: 2.1.14 Precedence: list Reply-To: The development of GNU GRUB List-Id: The development of GNU GRUB List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 08 Jun 2015 17:31:29 -0000 --XsQoSWH+UP9D9v3l Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Jun 08, 2015 at 07:51:44PM +0300, Andrei Borzenkov wrote: > =D0=92 Sun, 7 Jun 2015 11:24:46 +0100 > Ross Lagerwall =D0=BF=D0=B8=D1=88=D0=B5=D1=82: >=20 > > Add a module, part_eltorito, to allow parsing of the El Torito boot > > catalog into partitions. This follows the El Torito Bootable CD-ROM > > Format Specification Version 1.0 and the UEFI Specification 2.5. > > In cases where the specification is unclear, the code follows the UEFI > > reference implementation. > >=20 > > This is useful when booting CDs in UEFI mode. Before, GRUB would not be > > able to use the embedded ESP from which it was executed, so it would > > have a root and prefix set to the top level of the CD. This could result > > in subtle configuration bugs, because the same ISO booted from a USB > > disk (using isohybrid) would have its root and prefix set to the > > embedded ESP because it can find it through the MBR. >=20 > You can already access ESP on hybrid image using e.g. (cd0,msdos1); why > is it not enough? This is about booting a CD in UEFI mode; it may not be a hybrid disc in which case it doesn't have an MBR. Also, in the case of a hybrid image booted using a CD, the mismatch between the 2048 byte sectors of the CD and the 512 byte sector values used in the MBR means that GRUB is not able to access the correctly ESP anyway. For these reasons, I think it is useful to parse the El Torito boot catalog. Regards, --=20 Ross Lagerwall --XsQoSWH+UP9D9v3l Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iF4EAREIAAYFAlV10VYACgkQMRWWudUHn2RCKwD+Nw08VJzuYegL92P58/9PvrWc 9JvYSYlYKjlDXdBtAiYA/1SJt6BbVUBqY7HvRRo/2eKHbiOHYzWt1X7jfL3Z9zWb =fNoq -----END PGP SIGNATURE----- --XsQoSWH+UP9D9v3l--