Enable GRUB UKI menu entries

[codefiles]

No description provided.

[codefiles]

A problem here is if more than one kernel is installed there will be multiple "Arch Linux" entries in the menu with the edit option being the only way to distinguish them.

The menu title comes from the PRETTY_NAME in .osrel, see grub-core/commands/blsuki.c:

  /*
   * Although .osrel is listed as optional in the UKI specification, the .osrel
   * section is needed to generate the GRUB menu entry title.
   */
  osrel = blsuki_get_val (entry, ".osrel", NULL);
  if (osrel == NULL)
    {
      grub_dprintf ("blsuki", "Skipping file %s with no '.osrel' key.\n", entry->filename);
      goto finish;
    }

  osrel_line = osrel;
  while ((key = uki_read_osrel (&osrel_line, &value)) != NULL)
    {
      if (grub_strcmp ("PRETTY_NAME", key) == 0)
	{
	  title = value;
	  break;
	}
    }

This could be alleviated by using recall previous entry with the addition of the following command.

grub-editenv /boot/grub/grubenv set blsuki_save_default=true

Edit:
This problem should be solved by the following commit (not in a release yet).
https://gitlab.freedesktop.org/gnu-grub/grub/-/commit/9be1b7564daa770fd5ff33e9052edc9893d81f84

[svartkanin]

I suppose that's fine for now and we can improve that in the future

[codefiles]

Maybe someone will see this and update the GRUB ArchWiki article.

The uki command was introduced in GRUB 2.14rc1:
https://gitlab.freedesktop.org/gnu-grub/grub/-/commit/14c2966c725774aa58a811dada3277c7095cbcb3

With this pull request the uki command is used to add menu entries for UKI files. These are the new steps archinstall takes when GRUB is selected along with UKI:

• Create /etc/grub.d/15_uki with the following contents:

  #! /bin/sh
  set -e
  
  cat << EOF
  if [ "\$grub_platform" = "efi" ]; then
    uki
  fi
  EOF

• Add executable permissions to the file.

  # chmod +x /etc/grub.d/15_uki
  

  Now when grub-mkconfig is executed it will use this file and generated menu entries for detected UKI files.

• Remove executable permissions from /etc/grub.d/10_linux to disable it.

  The file /etc/grub.d/10_linux detects kernel files (vmlinuz-*) and creates menu entries for them and their corresponding initramfs file (initramfs-*.img) when grub-mkconfig is executed. The UKI files will contain an initramfs so there is no need for these initramfs-*.img files. If initramfs-*.img files are not present the file /etc/grub.d/10_linux will generate menu entries but they will fail to boot when selected.

  # chmod -x /etc/grub.d/10_linux