[PATCH v9 00/11] Add basic Boot Loader Interface support

[Oliver Steffen]

This is a step towards supporting unified kernel images (UKI) in Grub.

Add a new module named bli.  It implements a small but quite useful part
of the Boot Loader Interface [0].  This interface uses EFI variables for
communication between the boot loader and the operating system.

This module sets two EFI variables under the vendor GUID
4a67b082-0a4c-41cf-b6c7-440b29bb8c4f:

- LoaderInfo: contains GRUB + <version number>.
  This allows the running operating system to identify the boot loader
  used during boot.

- LoaderDevicePartUUID: contains the partition UUID of the
  EFI System Partition (ESP). This is used by
  systemd-gpt-auto-generator [1] to find the root partitions (and
  others too), via partition type IDs [2]. This is especially useful for
  UKIs, where the kernel command line is fixed and usually does not
  contain any information about the root partition.

This module is only available on EFI platforms.

This series also unifies the GUID implementations and introduces a
printf format specifier for them: %pG.

[0] https://systemd.io/BOOT_LOADER_INTERFACE/
[1] 
https://www.freedesktop.org/software/systemd/man/systemd-gpt-auto-generator.html
[2] 
https://uapi-group.org/specifications/specs/discoverable_partitions_specification/

v9:
- Rebase to latest master branch
- Fix error handling in bli.c: get_part_uuid()
  And with that fix the NULL pointer issue discovered by Coverity
- Add NULL checks to grub_device_close() and grub_disk_close()
  These are not strictly needed anymore with the changed error handling
  in get_part_uuid().
  I leave the fate of this patch at the maintainer's discretion.

v8:
- https://mail.gnu.org/archive/html/grub-devel/2023-05/msg00128.html
- Rebase to latest master branch
- Fix the documentation build (I hope)
- Fix build on arm
- Make more grub_guid instances 'static'
- Move endian conversion back out of the grub_guid printf code

v7:
- https://mail.gnu.org/archive/html/grub-devel/2023-05/msg00005.html
- Add a "Modules" chapter to the documentation and describe the bli
  module there
- Reword some section headings in the documentation

v6:
- https://mail.gnu.org/archive/html/grub-devel/2023-04/msg00068.html
- Initialize the Boot Loader Interface on module load and remove the bli
  command.
- Extract code for grub_efi_set_variable_to_string()
- Improve error messages in the bli module
- Improve GUID printing code

v5:
- https://mail.gnu.org/archive/html/grub-devel/2023-03/msg00120.html
- Replace more grub_*_guid with the new grub_guid struct

v4:
- https://mail.gnu.org/archive/html/grub-devel/2023-03/msg00058.html
- Place grub_utf8_to_utf16_alloc() in kern/misc.c and use it in kern/efi.c
- bli: rework partition GUID code, improve error reporting
- Add documentation for the bli module
- Address other comments

v3:
- https://mail.gnu.org/archive/html/grub-devel/2023-03/msg00008.html
- Unify GUID implementations for GPT and EFI
- Add printf format specifier for GUIDs, drop guid print function from
  v2.
- WIP/Please comment: Started extracting utf8->utf16 code.  Where should
  this go?
- Address other comments

v2:
- https://mail.gnu.org/archive/html/grub-devel/2023-02/msg00099.html
- Addressed comments from Daniel
- Added a print function for gpt guids`
- Added integer overflow check in UTF16 conversion
- Added config drop-in file that loads the module on EFI

v1:
- https://mail.gnu.org/archive/html/grub-devel/2023-01/msg00104.html


Oliver Steffen (11):
  efi: Add grub_efi_set_variable_with_attributes()
  Unify GUID types
  kern/misc: Add a format specifier GUIDs
  grub-core: Make use of guid printf format specifier
  types.h: Add GRUB_SSIZE_MAX
  kern/misc, kern/efi: Extract UTF-8 to UTF-16 code
  efi: Add grub_efi_set_variable_to_string()
  docs: Reword section headings
  kern: check for NULL when closing devices and disks
  Add a module for the Boot Loader Interface
  util/grub.d: Activate bli module on EFI

 Makefile.util.def                    |   6 ++
 docs/grub.texi                       |  43 +++++++---
 grub-core/Makefile.core.def          |   6 ++
 grub-core/commands/acpi.c            |   4 +-
 grub-core/commands/bli.c             | 122 +++++++++++++++++++++++++++
 grub-core/commands/efi/efifwsetup.c  |   4 +-
 grub-core/commands/efi/loadbios.c    |  14 +--
 grub-core/commands/efi/lsefi.c       |  17 +---
 grub-core/commands/efi/lsefisystab.c |  10 +--
 grub-core/commands/efi/lssal.c       |   4 +-
 grub-core/commands/efi/smbios.c      |  12 +--
 grub-core/commands/efi/tpm.c         |   6 +-
 grub-core/commands/probe.c           |  14 ++-
 grub-core/disk/efi/efidisk.c         |   4 +-
 grub-core/disk/ldm.c                 |   2 +-
 grub-core/efiemu/i386/pc/cfgtables.c |   6 +-
 grub-core/efiemu/main.c              |   4 +-
 grub-core/efiemu/runtime/efiemu.c    |  14 +--
 grub-core/kern/device.c              |   3 +
 grub-core/kern/disk.c                |   4 +
 grub-core/kern/efi/acpi.c            |  12 +--
 grub-core/kern/efi/efi.c             | 109 ++++++++++++------------
 grub-core/kern/efi/fdt.c             |   2 +-
 grub-core/kern/efi/init.c            |   2 +-
 grub-core/kern/efi/sb.c              |   4 +-
 grub-core/kern/misc.c                | 113 ++++++++++++++++++++-----
 grub-core/loader/efi/fdt.c           |   2 +-
 grub-core/loader/efi/linux.c         |   4 +-
 grub-core/loader/i386/xnu.c          |  13 +--
 grub-core/loader/ia64/efi/linux.c    |   2 +-
 grub-core/net/drivers/efi/efinet.c   |   4 +-
 grub-core/partmap/gpt.c              |   4 +-
 grub-core/term/efi/console.c         |   2 +-
 grub-core/term/efi/serial.c          |   2 +-
 grub-core/video/efi_gop.c            |   8 +-
 grub-core/video/efi_uga.c            |   2 +-
 include/grub/efi/api.h               |  69 ++++++---------
 include/grub/efi/efi.h               |  23 +++--
 include/grub/efiemu/efiemu.h         |  10 +--
 include/grub/efiemu/runtime.h        |   2 +-
 include/grub/gpt_partition.h         |  13 +--
 include/grub/misc.h                  |   3 +
 include/grub/types.h                 |  11 +++
 util/grub-install.c                  |   2 +-
 util/grub-probe.c                    |   2 +-
 util/grub.d/25_bli.in                |  24 ++++++
 46 files changed, 487 insertions(+), 256 deletions(-)
 create mode 100644 grub-core/commands/bli.c
 create mode 100644 util/grub.d/25_bli.in

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2.40.1