Buildroot:ReproducibleBuilds
As part of a Google Summer of Code project, Atharva Lele works on reproducible builds.
Away time
Arnout is away on: 30-31/5; 10/6; some time in July; 15-19/8.
Meetings
Weekly meetings on appear.in/buildroot every Tuesdays at 14:30 UTC.
- 2019-W20
- introductions
- confirm overal actions and planning
- 2019-W21
- Confirmed that starting from next week, work is full-time on GSoC (end of exams)
- Review of the Yocto implementation
- differences: Yocto is a distribution, so has a cache of the outputm while buildroot does not
- SORCE_DATE_EPOCH and TZ: already done (depends on BR2_REPRODUCIBLE)
- Doing similar in Buildroot:
- Do a first build with a successfull config from autobuilders, after enabling BR2_REPRODUCIBLE
- Then mv $(O)/target to $(O)/target-1; make clean; make
- And then run diffoscope target-1 target/
- Identify diffoscope dependencies to run it in autobuilders (eventually)
- How to save and present the result on autobuilder site?
Yocto's Implementation
- Wiki page: Reproducible Builds
- Shared State Mechanism: If input metadata hashes are same, outputs are reused. If inputs have changed, tools from Reproducible-Builds to be used. Further development yet to be done.
- At this stage, binary contents should be same. However file timestamps (due to package managers) may be different.
- Static Timezone value: Bugzilla
- Adapted SOURCE_DATE_EPOCH: Bugzilla, Source-Date-Epoch - Reproducible Builds
- Archives generated with deterministic metadata (using archive tools' arguments)
- Remove non-deterministic data from rootfs
- Diffoscope data on their shared states: yocto-reproduciblebuilds-data
Planning
- Week 20: study how yocto does it
- Week 21: ...
- Week 22: do two builds in autobuild-run script