On 28/11/2023 at 08:11, Andrei Borzenkov wrote:
On Tue, Nov 28, 2023 at 9:45 AM Pascal Hambourg <[email protected]> wrote:
On 28/11/2023 at 04:44, Andrei Borzenkov wrote:
On 27.11.2023 23:06, Pascal Hambourg wrote:
But if I build an EFI GRUB core image with
grub-mkimage --prefix='(hd0,gpt4)' --format=x86_64-efi \
--output=/boot/efi/EFI/azerty/core.efi part_gpt ext2
(no / at the end of prefix), then when booting it, the $prefix value
seems to be the combination of the --prefix device and the $cmdpath path:
cmdpath=(hd0,gpt1)/EFI/azerty
prefix=(hd0,gpt4)/EFI/azerty
Is this expected behaviour ?
Yes. $prefix consists of two parts - device and the directory path. If
one of them is missing during initialization, grub attempts to guess and
fill it in.
Guessing a missing or incomplete device makes sense, but what is the use
case for guessing a missing path when the device is present ? AFAICS if
the devices in $cmdpath and --prefix do not match, the resulting $prefix
is doomed to failure.
I do not think it is done on purpose, it is more - garbage in, garbage
out. The file name without the path component is invalid, grub cannot
use it anyway.
In my experience, when I set prefix=(device) either by config file or
manually at the grub prompt, GRUB can use it just fine so it seems to be
perfectly valid. It is a prefix, not a full path, and as far as I can
see grub uses it by prepending it to some file path starting with /. So
as long as the resulting path is valid it should be fine.
So it should either drop the value passed in --prefix
or do something to make it usable. I suppose, ignoring the value in
--prefix in this case would be more logical
Wouldn't it be more logical to do something like this:
if prefix is empty
set prefix = cmdpath
else if device part is empty or incomplete
set missing device part from cmdpath
and do not touch the path part ?
