grub-mkimage

grub-mkimage

[Andrey Shuvikov]

Hello,

I was looking into how grub2 works and noticed that in
the load list in grub2/boot/i386/pc/diskboot.S sector
number is 8-byte integer, while 
grub2/util/i386/pc/grub-mkimage.c sets the number of
sectors to load at 4-byte offset. Because of this it
actually patches upper part of the sector rather than
number of sectors.

This is the changes I've made:

======================================================
--- grub-mkimage.old  Mon May 08 14:29:10 2006
+++ grub-mkimage.c  Mon Nov 13 13:41:01 2006
@@ -143,7 +143,7 @@ generate_image (const char *dir,
FILE *o
   
   /* i386 is a little endian architecture.  */
   *((grub_uint16_t *) (boot_img +
GRUB_DISK_SECTOR_SIZE
-          - GRUB_BOOT_MACHINE_LIST_SIZE + 4))
+          - GRUB_BOOT_MACHINE_LIST_SIZE + 8))
     = grub_cpu_to_le16 (num);
 
   grub_util_write_image (boot_img, boot_size, out);
======================================================

Sincerely,
Andrey Shuvikov


 
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Re: grub-mkimage

[Yoshinori K. Okuji]

On Monday 13 November 2006 19:51, Andrey Shuvikov wrote:
> I was looking into how grub2 works and noticed that in
> the load list in grub2/boot/i386/pc/diskboot.S sector
> number is 8-byte integer, while
> grub2/util/i386/pc/grub-mkimage.c sets the number of
> sectors to load at 4-byte offset. Because of this it
> actually patches upper part of the sector rather than
> number of sectors.

Thank you for your patch. I've checked it in right now.

Okuji

grub-mkimage

[Rev. Mr. Gary Meerschaert]

I am getting an error from grub-mkimage. The error is:

grub-mkimage: error: diskboot.img is not one sector size

Does anyone know how I can get this fixed? I am a newbee with grub 
internals, and I don't have a clue as to ho to size the progam.

Thanks,

Gary Meerschaert

Re: grub-mkimage

[Pavel Roskin]

On Sat, 2009-03-21 at 12:26 -0400, Rev. Mr. Gary Meerschaert wrote:
> I am getting an error from grub-mkimage. The error is:
> 
> grub-mkimage: error: diskboot.img is not one sector size
> 
> Does anyone know how I can get this fixed? I am a newbee with grub 
> internals, and I don't have a clue as to ho to size the progam.

First of all, please specify the version of GRUB.  I suggest that you
use the current code from Subversion.  I cannot reproduce your problem
with the current code.

Then check if the problem is in grub-mkimage or in diskboot.img.  If
diskboot.img is 512 bytes long, then grub-mkimage is wrong.  If
diskboot.img is not 512 bytes long, then the problem is in diskboot.img.

In any case, please describe your environment, such as the compiler
version, the arguments to the configure script and whatever else may be
needed for others to reproduce your problem.

-- 
Regards,
Pavel Roskin