Writing the primary GPT before the backup may lead to a confusing
situation: booting a freshly updated system could consistently fail and
next boot will fall back to the old system if writing the primary works
but writing the backup fails. If the backup is written first and fails
the primary is left in the old state so the next boot will re-try and
possibly fail in the exact same way. Making that repeatable should make
it easier for users to identify the error.
Additionally if the firmware and OS disagree on the disk size, making
the backup inaccessible to GRUB, then just skip writing the backup.
When this happens the automatic call to `coreos-setgoodroot` after boot
will take care of repairing the backup.
The firmware and the OS may disagree on the disk configuration and size.
Although such a setup should be avoided users are unlikely to know about
the problem, assuming everything behaves like the OS. Tolerate this as
best we can and trust the reported on-disk location over the firmware
when looking for the backup GPT. If the location is inaccessible report
the error as best we can and move on.
I personally think this reads easier. Also has the side effect of
directly comparing the primary and backup tables instead of presuming
they are equal if the crc32 matches.
This ensures all code modifying GPT data include the same sanity check
that repair does. If revalidation fails the status flags are left in the
appropriate state.
The header was being relocated without checking the new location is
actually safe. If the BIOS thinks the disk is smaller than the OS then
repair may relocate the header into allocated space, failing the final
validation check. So only move it if the disk has grown.
Additionally, if the backup is valid then we can assume its current
location is good enough and leave it as-is.
Use the new status function which checks *_HEADER_VALID and
*_ENTRIES_VALID bits together. It doesn't make sense for the header and
entries bits to mismatch so don't allow for it.
Portions of the code attempted to handle the fact that GPT entries on
disk may be larger than the currently defined struct while others
assumed the data could be indexed by the struct size directly. This
never came up because no utility uses a size larger than 128 bytes but
for the sake of safety we need to do this by the spec.
GPT_BOTH_VALID is 4 bits so simple a boolean check is not sufficient.
This broken condition allowed gptprio to trust bogus disk locations in
headers that were marked invalid causing arbitrary disk corruption.
GRUB assumes that no disk is ever larger than 1EiB and rejects
reads/writes to such locations. Unfortunately this is not conveyed in
the usual way with the special GRUB_DISK_SIZE_UNKNOWN value.
send client arch in bootp requests, for now BIOS and x64/aarch64 EFI is
supported.
fix a bug introduced in 4d5d7be005 where
user class was encoded improperly, although this didn't seem to have any
detrimental effects.
properly insert an option terminator.
