From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with archive (Exim 4.43) id 1MXFfF-0004QL-AN for mharc-grub-devel@gnu.org; Sat, 01 Aug 2009 10:34:25 -0400 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1MXFfD-0004NL-JX for grub-devel@gnu.org; Sat, 01 Aug 2009 10:34:23 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1MXFf9-0004LC-2M for grub-devel@gnu.org; Sat, 01 Aug 2009 10:34:23 -0400 Received: from [199.232.76.173] (port=44992 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1MXFf8-0004L5-UE for grub-devel@gnu.org; Sat, 01 Aug 2009 10:34:18 -0400 Received: from xvm-190-8.ghst.net ([217.70.190.8]:47469 helo=aybabtu.com) by monty-python.gnu.org with esmtps (TLS-1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1MXFf8-00039a-8z for grub-devel@gnu.org; Sat, 01 Aug 2009 10:34:18 -0400 Received: from [192.168.10.10] (helo=thorin) by aybabtu.com with esmtp (Exim 4.69) (envelope-from ) id 1MXFf6-0001EY-CM for grub-devel@gnu.org; Sat, 01 Aug 2009 14:34:16 +0000 Received: from rmh by thorin with local (Exim 4.69) (envelope-from ) id 1MXFf5-00060R-P8 for grub-devel@gnu.org; Sat, 01 Aug 2009 16:34:15 +0200 Date: Sat, 1 Aug 2009 16:34:15 +0200 From: Robert Millan To: The development of GRUB 2 Message-ID: <20090801143415.GD22989@thorin> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Organization: free as in freedom X-Message-Flag: Worried about Outlook viruses? Switch to Thunderbird! www.mozilla.com/thunderbird X-Debbugs-No-Ack: true User-Agent: Mutt/1.5.18 (2008-05-17) X-detected-operating-system: by monty-python.gnu.org: GNU/Linux 2.6 (newer, 3) Subject: Re: [RFC] Don't pass filename in multiboot command line X-BeenThere: grub-devel@gnu.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: The development of GRUB 2 List-Id: The development of GRUB 2 List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 01 Aug 2009 14:34:24 -0000 On Sat, Aug 01, 2009 at 03:23:04PM +0200, Vladimir 'phcoder' Serbinenko wrote: > According to multiboot specification "It should be possible to write > compliant boot loaders that load the OS image from a variety of > sources, including floppy disk, hard disk, and across a network. " > It implicitly says that kernel shouldn't care about filename used by > bootloader. About commandline it's only said: > "If bit 2 of the `flags' longword is set, the `cmdline' field is > valid, and contains the physical address of the command line to be > passed to the kernel. The command line is a normal C-style > zero-terminated string" > Currently grub however passes filename as first argument of command line. > Felix Zielcke did a series of tests and it revealed that OSes > subdivide into two categories: > 1) Ones that don't care whether this argument is omitted altogether or > not (e.g. the don't ignore second argument even if filename is > omitted) > 2) Solaris (for kernel name) and AROS (for module name) both assume > that filename is the same under grub and OS. This assumption isn't > necessarily true. These OSes are broken one way or another. If we omit > the first argument user can workaround the problem by supplying > kernel/module OS image name as first argument of multiboot/module > command line > E.g. > multiboot /RPOOL/opensolaris/@/platform/i86pc/kernel /platform/i86pc/kernel I agree with this. But please wait a few days to give everyone a chance to read it. Regarding the patch: > /* Figure out cmdline length. */ > - for (i = 0, cmdline_length = 0; i < argc; i++) > + for (i = 1, cmdline_length = 0; i < argc; i++) > cmdline_length += grub_strlen (argv[i]) + 1; > > + if (cmdline_length == 0) > + cmdline_length = 1; > + > > boot_loader_name_length = sizeof(PACKAGE_STRING); > > #define cmdline_addr(x) ((void *) ((x) + code_size)) > @@ -351,14 +354,16 @@ grub_multiboot (int argc, char *argv[]) > if (! cmdline) > goto fail; > > - for (i = 0; i < argc; i++) > + for (i = 1; i < argc; i++) > { > p = grub_stpcpy (p, argv[i]); > *(p++) = ' '; > } > > /* Remove the space after the last word. */ > - *(--p) = '\0'; > + if (p != cmdline) > + p--; > + *p = 0; > > mbi->flags |= MULTIBOOT_INFO_CMDLINE; > mbi->cmdline = (grub_uint32_t) cmdline_addr (grub_multiboot_payload_dest); > @@ -422,9 +427,12 @@ grub_module (int argc, char *argv[]) > goto fail; > } > > - for (i = 0; i < argc; i++) > + for (i = 1; i < argc; i++) > len += grub_strlen (argv[i]) + 1; > > + if (len == 0) > + len = 1; > + > cmdline = p = grub_malloc (len); > if (! cmdline) > goto fail; > @@ -436,7 +444,9 @@ grub_module (int argc, char *argv[]) > } > > /* Remove the space after the last word. */ > - *(--p) = '\0'; > + if (p != cmdline) > + p--; > + *p = '\0'; There's a much simpler way to address this. Just add something like: cmdline_argv = argv + 1; cmdline_argc = argc - 1; at the beginning, and then use cmdline_argv and cmdline_argc instead of correcting the off-by-one every time. -- Robert Millan The DRM opt-in fallacy: "Your data belongs to us. We will decide when (and how) you may access your data; but nobody's threatening your freedom: we still allow you to remove your data and not access it at all."