tree e6fb7c69836e3bfd9a16795a78285c5df768913d
parent 420f7f8df45b16aa984396270419cacf11baeab6
author Tao Bao <tbao@google.com> 1525718305 -0700
committer Tao Bao <tbao@google.com> 1525730700 -0700

updater: Skip an updated partition on retry.

Prior to the change, the BBOTA updater would try to re-run all the
commands for a given partition on retry, including creating stashes
according to the list of commands. This could fail a retry when the
previous update had moved on to next stage, with leftovers in /cache.

This CL creates a marker on /cache upon successfully updating a
partition. The update commands will be skipped when trying to apply
updates on an updated partition. Note that the marker is expected to be
removed while doing a normal boot (in particular, handled by
RecoverySystem#handleAftermath). If that didn't happen, the updater
would also remove the marker before starting next fresh update.

Alternatively, we can achieve the same goal by changing the OTA script,
which needs to additionally compare the checksum against the target
build. For example,

  range_sha1("/system", "ranges") == SHA1_of_updated_system ||
  block_image_update("/system");

The downside is that we need to pay that cost on each install, as the
edify script doesn't support caching the result in a variable.

Bug: 79165963
Test: Simulate the process on device (by triggering a reboot while
      updating /vendor). Check the update log and result.
Change-Id: I731031fa336133e1221b33edfc469969706e8091