fastboot: Implement helper commands for Virtual A/B.
This introduces two new commands to the fastboot protocol:
- getvar snapshot-update-status - Return "none", "snapshotted", or
"merging" depending on the current status set by the boot control
HAL.
- snapshot-update [cancel] - Cancel any pending snapshot-based updates
via the boot control HAL. After this, the HAL should return
MergeStatus::CANCELLED and "update-merge-status" should be "none".
If no argument is specified, the snapshot-update-status is returned
via an INFO response.
Bootloaders are expected to implement this in a manner consistent with
the boot control HAL.
Fastboot-based tooling should expect wipes of userdata to fail when
update-merge-status returns "merging". Thus, the force flag now cancel
any pending snapshots.
Bug: 139154945
Test: fastboot getvar snapshot-update-status
fastboot snapshot-update cancel
fastboot snapshot-update
Change-Id: Idc423fe7656b212e929e64eb0e6b85b453e0e8dc
10 files changed