Re: [PATCH] use UUIDs for cross-disk installs (Re: Issue with boot != root and chainloading)

[Robert Millan <rmh@aybabtu.com>]

Aside from the discussion about removing / refurbishing make_install_device(),
is everybody ok with what this patch does?

If I don't hear any objections I'll commit it soon.

On Sat, Jul 26, 2008 at 12:10:50AM +0200, Robert Millan wrote:
> 2008-07-26  Robert Millan  <rmh@aybabtu.com>
> 
> 	* include/grub/i386/pc/kernel.h (GRUB_KERNEL_MACHINE_DATA_END):
> 	Increase from 0x50 to 0x60.
> 	* util/i386/pc/grub-install.in: Detect cross-disk installs, and
> 	use UUIDs to identify the root drive for them.  If that's not
> 	possible, abort.
> 	* util/i386/pc/grub-setup.c (setup): Do not special-case, or even
> 	check, for cross-disk installs.
> 
> Index: include/grub/i386/pc/kernel.h
> ===================================================================
> --- include/grub/i386/pc/kernel.h	(revision 1733)
> +++ include/grub/i386/pc/kernel.h	(working copy)
> @@ -41,7 +41,7 @@
>  #define GRUB_KERNEL_MACHINE_PREFIX		0x20
>  
>  /* End of the data section. */
> -#define GRUB_KERNEL_MACHINE_DATA_END		0x50
> +#define GRUB_KERNEL_MACHINE_DATA_END		0x60
>  
>  /* The size of the first region which won't be compressed.  */
>  #if defined(ENABLE_LZO)
> Index: util/i386/pc/grub-install.in
> ===================================================================
> --- util/i386/pc/grub-install.in	(revision 1733)
> +++ util/i386/pc/grub-install.in	(working copy)
> @@ -233,15 +233,34 @@
>  # Device abstraction module, if any (lvm, raid).
>  devabstraction_module=`$grub_probe --target=abstraction --device ${grub_device}`
>  
> +# The order in this list is critical.  Be careful when modifying it.
> +modules="$modules $fs_module $partmap_module biosdisk $devabstraction_module"
> +
> +prefix_drive=
>  if [ "x${devabstraction_module}" = "x" ] ; then
> -    prefix_drive=
> +    if echo "${install_device}" | grep -qx "(.*)" ; then
> +      install_drive="${install_device}"
> +    else
> +      install_drive="`$grub_probe --target=drive --device ${install_device}`"
> +    fi
> +    grub_drive="`$grub_probe --target=drive --device ${grub_device}`"
> +
> +    # Strip partition number
> +    install_drive="`echo ${install_drive} | sed -e s/,[0-9]*//g`"
> +    grub_drive="`echo ${grub_drive} | sed -e s/,[0-9]*//g`"
> +    if [ "x${grub_drive}" != "x${install_drive}" ] ; then
> +        uuid="`$grub_probe --target=fs_uuid --device ${grub_device}`"
> +        if [ "x${uuid}" = "x" ] ; then
> +          echo "You attempted a cross-disk install, but the filesystem containing ${grubdir} does not support UUIDs." 1>&2
> +          exit 1
> +        fi
> +        prefix_drive="(UUID=${uuid})"
> +        modules="$modules fs_uuid"
> +    fi
>  else
>      prefix_drive=`$grub_probe --target=drive --device ${grub_device}`
>  fi
>  
> -# The order in this list is critical.  Be careful when modifying it.
> -modules="$modules $fs_module $partmap_module biosdisk $devabstraction_module"
> -
>  grub_prefix="${prefix_drive}`make_system_path_relative_to_its_root ${grubdir}`" || exit 1
>  
>  $grub_mkimage --output=${grubdir}/core.img --prefix=${grub_prefix}/ $modules || exit 1
> Index: util/i386/pc/grub-setup.c
> ===================================================================
> --- util/i386/pc/grub-setup.c	(revision 1733)
> +++ util/i386/pc/grub-setup.c	(working copy)
> @@ -339,18 +339,12 @@
>  	  if (grub_disk_write (dest_dev->disk, embed_region.start, 0, core_size, core_img))
>  	    grub_util_error ("%s", grub_errmsg);
>  
> -	  /* The boot image and the core image are on the same drive,
> -	     so there is no need to specify the boot drive explicitly.  */
> -	  *boot_drive = 0xff;
> +	  /* FIXME: can this be skipped?  */
> +	  *boot_drive = 0xFF;
> +	  *root_drive = 0xFF;
> +
>  	  *kernel_sector = grub_cpu_to_le64 (embed_region.start);
>  
> -          /* If the root device is different from the destination device,
> -             it is necessary to embed the root drive explicitly.  */
> -          if (root_dev->disk->id != dest_dev->disk->id)
> -            *root_drive = (grub_uint8_t) root_dev->disk->id;
> -          else
> -            *root_drive = 0xFF;
> -
>  	  /* Write the boot image onto the disk.  */
>  	  if (grub_disk_write (dest_dev->disk, 0, 0, GRUB_DISK_SECTOR_SIZE,
>  			       boot_img))
> @@ -480,15 +474,8 @@
>    
>    *kernel_sector = grub_cpu_to_le64 (first_sector);
>  
> -  /* If the destination device is different from the root device,
> -     it is necessary to embed the boot drive explicitly.  */
> -  if (root_dev->disk->id != dest_dev->disk->id)
> -    *boot_drive = (grub_uint8_t) root_dev->disk->id;
> -  else
> -    *boot_drive = 0xFF;
> -
> -  /* When the core image is not embedded, the root device always follows
> -     the boot device.  */
> +  /* FIXME: can this be skipped?  */
> +  *boot_drive = 0xFF;
>    *root_drive = 0xFF;
>  
>    *install_dos_part = grub_cpu_to_le32 (dos_part);

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-- 
Robert Millan

<GPLv2> I know my rights; I want my phone call!
<DRM> What good is a phone call… if you are unable to speak?
(as seen on /.)