# external_update_binary

Provides the `applypatch`/`updater`/`edify` stack — the code that builds the
`updater` binary embedded as `update-binary` inside a non-A/B OTA zip, and
interpreted by recovery's `install/install.cpp` (`SetUpNonAbUpdateCommands()`)
at install time.

## Why this repo exists

Google deleted this source from AOSP outright in commit `c7ebad5f`
("rm -rf non-AB code", 2024-04-05, Bug 324360816) — confirmed present in the
android-14 tag, absent from android-16.0.0_r4. The *runtime* side survived
(`install/install.cpp` in stock `bootable/recovery` still unconditionally
extracts and executes `update-binary` from an OTA zip) and the *build-side
packaging* survived too (`ota_from_target_files.py` still has
`GenerateNonAbOtaPackage`/`--binary`) — only the source that builds the
`updater` executable itself was removed. This repo restores just that piece,
sourced from TeamWin's `android_bootable_recovery` (`android-14.1` branch),
the only living copy found.

Kept as its own repo rather than folded into a recovery fork so it's
buildable independent of whichever recovery UI PawletOS ends up using (stock
AOSP UI or a TWRP-derived one) — see `PawletOS/NOTES-ota-recovery-ab.md` in
the main workspace for the full investigation.

## Layout

- `applypatch/` — binary patch application (`imgpatch`, `bspatch`), plus the
  standalone `applypatch`/`imgdiff` tools. Self-contained Soong module, no
  changes made against TeamWin's source.
- `updater/` — the `updater` executable itself (`updater/Android.mk`,
  `LOCAL_MODULE := updater`) and its supporting static libs
  (`libupdater_core`, `libupdater_device`, `libupdater_host`). Uses classic
  `Android.mk`/`BUILD_EXECUTABLE` — verified still supported in
  raspberry-vanilla's `android-16.0` `build/make` fork (`core/executable.mk`
  present, `LOCAL_FORCE_STATIC_EXECUTABLE` handling present).
- `edify/` — the scripting language `updater-script` is written in
  (`libedify`: lexer/parser/expression evaluator).

## What was intentionally left out

- `install/ZipUtil.cpp`, `install/get_args.cpp`, `install/set_metadata.cpp` —
  these existed in TeamWin's tree but are wired only into *their* modified
  `install.cpp` (bootable/recovery's top-level `Android.bp`), which PawletOS
  is not adopting (stock `install.cpp` is being kept as-is). Confirmed
  `twrpinstall` (a separate standalone module, not part of this repo) ships
  its own independent copies of `ZipUtil`/`get_args`, so nothing depends on
  the ones that used to live here. Left out rather than carried along as
  dead weight.
- `uncrypt/Android.mk` — `uncrypt` still exists, unmodified, in stock
  `bootable/recovery`. Nothing to restore there.

## Compatibility notes (android-16.0.0_r4, raspberry-vanilla build)

- Adapted `updater/Android.bp` and `edify/Android.bp` to declare their own
  `license {}` module instead of referencing bootable/recovery's internal
  `bootable_recovery_license` name — keeps this repo buildable without a
  hard coupling to bootable/recovery's own license plumbing. `applypatch/`
  already declared its own license module upstream, left as-is.
- All `static_libs`/`shared_libs` dependencies referenced
  (`libbootloader_message`, `libotautil`, `libavb`, `liblp`, `libdm`,
  `libfec`/`libfec_rs`, `libselinux`, `libsparse`, `libsquashfs_utils`,
  `libbrotli`, `libbz`, `libziparchive`, `libbase`, `libcrypto_utils`,
  `libbsdiff`, `libdivsufsort`/`libdivsufsort64`) are long-stable AOSP
  library names from `system/`/`external/`, not modified by PawletOS or
  raspberry-vanilla — not individually re-verified against the android-16.0
  tag, flagged here in case a build turns one of these up as missing.
- Not yet build-tested end to end (no local AOSP build environment
  available in this workspace) — the checks above were done by reading
  source and grepping actual cloned trees, not by compiling.

## License

Apache License 2.0 (see `NOTICE`), consistent with the upstream AOSP/TeamWin
source this was derived from.