[GRUB PARTUUID PATCH V10 0/4] Add PARTUUID detection support

[Nicholas Vinson]

Summary of Changes:
    - Defined print_gpt_puid()
        - Updated grub-probe.c to use print_gpt_guid()
    - Renamed struct grub_gpt_part_type to struct grub_gpt_part_guid.
    - Updated struct typedef to use grub_gpt_part_guid
    - Replaced grub_gpt_part_type_t type with grub_gpt_part_guid_t in
        variable declarations.
    - Changed grub_gpt_partentry.guid from a 16 byte array to
        grub_gpt_part_guid.
    - Added PRINT_PARTUUID enum element to enum defined in
        util/grub-probe.c.
    - Added "partuuid" string to targets array defined in
        util/grub-probe.c.
    - Defined probe_partuuid() function.
    - Added GRUB_DISABLE_LINUX_PARTUUID item to docs/grub/texi
    - Defined GRUB_DEVICE_PARTUUID variable util/grub-mkconfig.in
    - Updated exports to export GRUB_DEVICE_PARTUUID and
        GRUB_DISABLE_LINUX_PARATUUID variables.
    - Updated rootfs detection logic in util/grub.d/10_linux.in to favor
        partition UUIDs when GRUB_DISABLE_LINUX_PARTUUID is not set to
        'true' and no initramfs is found (this also includes cases where
        GRUB_DISABLE_LINUX_PARTUUID is unset) or when an initramfs is
        found and GRUB_DISABLE_LINUX_UUID is set to 'true'.
    - Updated rootfs detection logic in util/grub.d/20_linux_xen.in to
        favor partition UUIDs when GRUB_DISABLE_LINUX_PARTUUID is not
        set to 'true' and no initramfs is found (this also includes
        cases where GRUB_DISABLE_LINUX_PARTUUID is unset) or when an
        initramfs is found and GRUB_DISABLE_LINUX_UUID is set to 'true'.

Changes from Patch v9:
    - Merged optional patch with updage grub script template files patch
    - Updated util/grub.d/20_linux_xen.in to use new partuuid logic
    - Updated documentation on GRUB_DISABLE_LINUX_PARTUUID

Changes from Patch v8:
    - Renamed GRUB_ENABLE_LINUX_PARTUUID to GRUB_DISABLE_LINUX_PARTUUID
    - Updated the 10_linux logic so GRUB_ENABLE_LINUX_PARTUUID and
        GRUB_ENABLE_LINUX_UUID would behave more independently.
    - Documented interactions of GRUB_DISABLE_LINUX_UUID,
        GRUB_DISABLE_LINUX_PARTUUID, and initramfs detection in commit
        message.
    - Added optional patch that sets GRUB_DISABLE_LINUX_PARTUUID to true
        by default.
    - Fixed merge conflicts between this patchset and upstream's master
        branch.

Changes from Patch v7:
    - Changed checks in probe_partuuid() to use the variable 'p' instead
      of disk->partition
    - Moved 'disk->partition = p;' assignment to inside the
        'p & p->parent == NULL' statement
    - Moved 'disk->partition = p->parent;' assignment to before partmap
          name checks.
    - Fixed formatting issues.
    - Copied Daniel Kiper's reviewed-by line to unaltered patches.

Changes from Patch v6:
    - Corrected spelling and grammatical errors in description text for
      GRUB_ENABLE_LINUX_PARTUUID
    - Moved disk->partition save & restore logic to beginning and end of
      probe_partuuid()
    - Fixed formatting errors in probe_partuuid

Changes from Patch v5:
    - Added sign-off by lines
    - Fixed formatting errors found by Daniel Kiper

Changes from Patch v4:
    - Updated grub.texi to reflect new behavior for
      GRUB_ENABLE_LINUX_PARTUUID

    - Updated 10_linux.in logic to favor the PARTUUID when
      GRUB_ENABLE_LINUX_PARTUUID is enabled and GRUB_DISABLE_LINUX_UUID
      is disabled.

Changes from Patch v3:
    - Removed flex-2.6.3 compatibility patch

    - Removed Steve Kenton's patch

Changes from Patch v2:
    - Added flex-2.6.3 compatibility patch

    - Fixed a GPT partition read error

    - Added Steve Kenton's patch

    - Changed struct grub_part_gpt_type name to struct
      grub_part_gpt_part_guid

    - Changed grub_part_gpt_type_t typedef name to grub_part_gpt_guid_t

    - Added sprint_gpt_guid to Steve Kenton's patch

    - Updated v1 and Steve Kenton's patch to use similar methods when
      reading partition GUIDs.

Changes from Patch v1:
    - Added GRUB_ENABLE_LINUX_PARTUUID variable description to grub.texi

    - Removed added gpt_part_guid copy logic from
      grub_gpt_partition_map_iterate()

    - Removed added NT disk signature copy logic from
      grub_partition_msdos_iterate()

    - Removed modifications to partition number increment logic

    - Removed added guid union definition.

    - Added GRUB_ENABLE_LINUX_PARTUUID to grub-mkconfig.in export list

    - Moved PRINT_GPT_PARTTYPE printing logic to print_gpt_guid()
      function in grub-probe.c

    - Updated PRINT_GPT_PARTTYPE case to call print_gpt_guid() function
      in grub-probe.c.

    - Created probe_partuuid() function in grub-probe.c

    - Updated print == PRINT_PARTUUID check logic in probe() to call
      probe_partuuid().

    - Updated UUID logic in 10_linux.in to enable root=PARTUUID feature
      only if GRUB_DISABLE_LINUX_UUID is not set to true,
      and GRUB_DEVICE_PARTUUID is not empty, GRUB_ENABLE_LINUX_PARTUUID
      is set to true.

Hello,

This is a request to add PARTUUID detection support grub-probe for MBR
and GPT partition schemes.  The Linux kernel supports mounting the root
filesystem by Linux device name or by the Partition [GU]UID.  GRUB's
mkconfig, however, currently only supports specifying the rootfs in the
kernel command-line by Linux device name unless an initramfs is also
present.  When an initramfs is present GRUB's mkconfig will set the
kernel's root parameter value to either the Linux device name or to the
filesystem [GU]UID.

Therefore, the only way to protect a Linux system from failing to boot
when its Linux storage device names change is to either manually edit
grub.cfg or /etc/default/grub and append root=PARTUUID=xxx to the
command-line or create an initramfs that understands how to mount
devices by filesystem [G]UID and let grub-mkconfig pass the filesystem
[GU]UID to the initramfs.

The goal of this patch set is to enable root=PARTUUID=xxx support in
grub-mkconfig, so that users don't have to manually edit
/etc/default/grub or grub.cfg, or create an initramfs for the sole
purpose of having a robust bootloader configuration for Linux.

Thanks,
Nicholas Vinson

Nicholas Vinson (4):
  Centralize guid prints
  Update grub_gpt_partentry
  Add PARTUUID detection support to grub-probe
  Update grub script template files

 docs/grub.texi               | 11 ++++++
 grub-core/disk/ldm.c         |  2 +-
 grub-core/partmap/gpt.c      |  4 +-
 include/grub/gpt_partition.h |  8 ++--
 util/grub-install.c          |  2 +-
 util/grub-mkconfig.in        |  3 ++
 util/grub-probe.c            | 76 +++++++++++++++++++++++++++++-------
 util/grub.d/10_linux.in      | 22 +++++++++--
 util/grub.d/20_linux_xen.in  | 22 +++++++++--
 9 files changed, 121 insertions(+), 29 deletions(-)

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2.17.0