[bug #33445] please add an opportunity to chainload complete files

[Mario 'BitKoenig' Holbe]

URL:
  <http://savannah.gnu.org/bugs/?33445>

                 Summary: please add an opportunity to chainload complete
files
                 Project: GNU GRUB
            Submitted by: holbe
            Submitted on: Tue May 31 13:37:02 2011
                Category: Booting
                Severity: Major
                Priority: 5 - Normal
              Item Group: Feature Request
                  Status: None
                 Privacy: Public
             Assigned to: None
         Originator Name: 
        Originator Email: 
             Open/Closed: Open
         Discussion Lock: Any
                 Release: 
                 Release: Bazaar - trunk
         Reproducibility: None
         Planned Release: None

    _______________________________________________________

Details:

Hello,

It would be great to have an opportunity to chainload complete files. This way
grub could, for example, boot PXE loaders.

In my specific case I'm trying to boot a detached DiskCryptor boot loader.
DiskCryptor offers two alternatives for detached boot loaders: an ISO image or
a PXE image.
The ISO image can be loaded through syslinux memdisk and this works well, but
is quite a lot of overhead for just a simple boot loader.
Hence, I tried to chainload the PXE image. This shouldn't be a big issue in
general since both, i386 boot sectors as well as i386 PXE loaders expect to be
loaded to 0:7C00. Unfortunately chainloading does not work yet, because the
current `chainloader' (--force) implementation does only load a single sector.
Offering an option to chainload the whole file (--pxe? --whole? --full?)
should make this work.

I was able to successfully boot this specific DiskCryptor loader using
`ntldr'. I don't know exactly why this works and whether this is intentional
or just an accident, because if I got the code right, `ntldr' loads to
2000:7C00. So the reason for this this to work is probably just careful
programming of the DiskCryptor loader not to rely on being loaded at segment
0.

An opportunity to chainload complete files could probably also solve bug
#31979.


Thanks for your work & regards
   Mario




    _______________________________________________________

Reply to this item at:

  <http://savannah.gnu.org/bugs/?33445>

_______________________________________________
  Message sent via/by Savannah
  http://savannah.gnu.org/