Search Results: "lex"

24 March 2024

Niels Thykier: debputy v0.1.21

Earlier today, I have just released debputy version 0.1.21 to Debian unstable. In the blog post, I will highlight some of the new features.
Package boilerplate reduction with automatic relationship substvar Last month, I started a discussion on rethinking how we do relationship substvars such as the $ misc:Depends . These generally ends up being boilerplate runes in the form of Depends: $ misc:Depends , $ shlibs:Depends where you as the packager has to remember exactly which runes apply to your package. My proposed solution was to automatically apply these substvars and this feature has now been implemented in debputy. It is also combined with the feature where essential packages should use Pre-Depends by default for dpkg-shlibdeps related dependencies. I am quite excited about this feature, because I noticed with libcleri that we are now down to 3-5 fields for defining a simple library package. Especially since most C library packages are trivial enough that debputy can auto-derive them to be Multi-Arch: same. As an example, the libcleric1 package is down to 3 fields (Package, Architecture, Description) with Section and Priority being inherited from the Source stanza. I have submitted a MR to show case the boilerplate reduction at https://salsa.debian.org/siridb-team/libcleri/-/merge_requests/3. The removal of libcleric1 (= $ binary:Version ) in that MR relies on another existing feature where debputy can auto-derive a dependency between an arch:any -dev package and the library package based on the .so symlink for the shared library. The arch:any restriction comes from the fact that arch:all and arch:any packages are not built together, so debputy cannot reliably see across the package boundaries during the build (and therefore refuses to do so at all). Packages that have already migrated to debputy can use debputy migrate-from-dh to detect any unnecessary relationship substitution variables in case you want to clean up. The removal of Multi-Arch: same and intra-source dependencies must be done manually and so only be done so when you have validated that it is safe and sane to do. I was willing to do it for the show-case MR, but I am less confident that would bother with these for existing packages in general. Note: I summarized the discussion of the automatic relationship substvar feature earlier this month in https://lists.debian.org/debian-devel/2024/03/msg00030.html for those who want more details. PS: The automatic relationship substvars feature will also appear in debhelper as a part of compat 14.
Language Server (LSP) and Linting I have long been frustrated by our poor editor support for Debian packaging files. To this end, I started working on a Language Server (LSP) feature in debputy that would cover some of our standard Debian packaging files. This release includes the first version of said language server, which covers the following files:
  • debian/control
  • debian/copyright (the machine readable variant)
  • debian/changelog (mostly just spelling)
  • debian/rules
  • debian/debputy.manifest (syntax checks only; use debputy check-manifest for the full validation for now)
Most of the effort has been spent on the Deb822 based files such as debian/control, which comes with diagnostics, quickfixes, spellchecking (but only for relevant fields!), and completion suggestions. Since not everyone has a LSP capable editor and because sometimes you just want diagnostics without having to open each file in an editor, there is also a batch version for the diagnostics via debputy lint. Please see debputy(1) for how debputy lint compares with lintian if you are curious about which tool to use at what time. To help you getting started, there is a now debputy lsp editor-config command that can provide you with the relevant editor config glue. At the moment, emacs (via eglot) and vim with vim-youcompleteme are supported. For those that followed the previous blog posts on writing the language server, I would like to point out that the command line for running the language server has changed to debputy lsp server and you no longer have to tell which format it is. I have decided to make the language server a "polyglot" server for now, which I will hopefully not regret... Time will tell. :) Anyhow, to get started, you will want:
$ apt satisfy 'dh-debputy (>= 0.1.21~), python3-pygls'
# Optionally, for spellchecking
$ apt install python3-hunspell hunspell-en-us
# For emacs integration
$ apt install elpa-dpkg-dev-el markdown-mode-el
# For vim integration via vim-youcompleteme
$ apt install vim-youcompleteme
Specifically for emacs, I also learned two things after the upload. First, you can auto-activate eglot via eglot-ensure. This badly feature interacts with imenu on debian/changelog for reasons I do not understand (causing a several second start up delay until something times out), but it works fine for the other formats. Oddly enough, opening a changelog file and then activating eglot does not trigger this issue at all. In the next version, editor config for emacs will auto-activate eglot on all files except debian/changelog. The second thing is that if you install elpa-markdown-mode, emacs will accept and process markdown in the hover documentation provided by the language server. Accordingly, the editor config for emacs will also mention this package from the next version on. Finally, on a related note, Jelmer and I have been looking at moving some of this logic into a new package called debpkg-metadata. The point being to support easier reuse of linting and LSP related metadata - like pulling a list of known fields for debian/control or sharing logic between lintian-brush and debputy.
Minimal integration mode for Rules-Requires-Root One of the original motivators for starting debputy was to be able to get rid of fakeroot in our build process. While this is possible, debputy currently does not support most of the complex packaging features such as maintscripts and debconf. Unfortunately, the kind of packages that need fakeroot for static ownership tend to also require very complex packaging features. To bridge this gap, the new version of debputy supports a very minimal integration with dh via the dh-sequence-zz-debputy-rrr. This integration mode keeps the vast majority of debhelper sequence in place meaning most dh add-ons will continue to work with dh-sequence-zz-debputy-rrr. The sequence only replaces the following commands:
  • dh_fixperms
  • dh_gencontrol
  • dh_md5sums
  • dh_builddeb
The installations feature of the manifest will be disabled in this integration mode to avoid feature interactions with debhelper tools that expect debian/<pkg> to contain the materialized package. On a related note, the debputy migrate-from-dh command now supports a --migration-target option, so you can choose the desired level of integration without doing code changes. The command will attempt to auto-detect the desired integration from existing package features such as a build-dependency on a relevant dh sequence, so you do not have to remember this new option every time once the migration has started. :)

Jacob Adams: Regular Reboots

Uptime is often considered a measure of system reliability, an indication that the running software is stable and can be counted on. However, this hides the insidious build-up of state throughout the system as it runs, the slow drift from the expected to the strange. As Nolan Lawson highlights in an excellent post entitled Programmers are bad at managing state, state is the most challenging part of programming. It s why did you try turning it off and on again is a classic tech support response to any problem. In addition to the problem of state, installing regular updates periodically requires a reboot, even if the rest of the process is automated through a tool like unattended-upgrades. For my personal homelab, I manage a handful of different machines running various services. I used to just schedule a day to update and reboot all of them, but that got very tedious very quickly. I then moved the reboot to a cronjob, and then recently to a systemd timer and service. I figure that laying out my path to better management of this might help others, and will almost certainly lead to someone telling me a better way to do this. UPDATE: Turns out there s another option for better systemd cron integration. See systemd-cron below.

Stage One: Reboot Cron The first, and easiest approach, is a simple cron job. Just adding the following line to /var/spool/cron/crontabs/root1 is enough to get your machine to reboot once a month2 on the 6th at 8:00 AM3:
0 8 6 * * reboot
I had this configured for many years and it works well. But you have no indication as to whether it succeeds except for checking your uptime regularly yourself.

Stage Two: Reboot systemd Timer The next evolution of this approach for me was to use a systemd timer. I created a regular-reboot.timer with the following contents:
[Unit]
Description=Reboot on a Regular Basis
[Timer]
Unit=regular-reboot.service
OnBootSec=1month
[Install]
WantedBy=timers.target
This timer will trigger the regular-reboot.service systemd unit when the system reaches one month of uptime. I ve seen some guides to creating timer units recommend adding a Wants=regular-reboot.service to the [Unit] section, but this has the consequence of running that service every time it starts the timer. In this case that will just reboot your system on startup which is not what you want. Care needs to be taken to use the OnBootSec directive instead of OnCalendar or any of the other time specifications, as your system could reboot, discover its still within the expected window and reboot again. With OnBootSec your system will not have that problem. Technically, this same problem could have occurred with the cronjob approach, but in practice it never did, as the systems took long enough to come back up that they were no longer within the expected window for the job. I then added the regular-reboot.service:
[Unit]
Description=Reboot on a Regular Basis
Wants=regular-reboot.timer
[Service]
Type=oneshot
ExecStart=shutdown -r 02:45
You ll note that this service is actually scheduling a specific reboot time via the shutdown command instead of just immediately rebooting. This is a bit of a hack needed because I can t control when the timer runs exactly when using OnBootSec. This way different systems have different reboot times so that everything doesn t just reboot and fail all at once. Were something to fail to come back up I would have some time to fix it, as each machine has a few hours between scheduled reboots. One you have both files in place, you ll simply need to reload configuration and then enable and start the timer unit:
systemctl daemon-reload
systemctl enable --now regular-reboot.timer
You can then check when it will fire next:
# systemctl status regular-reboot.timer
  regular-reboot.timer - Reboot on a Regular Basis
     Loaded: loaded (/etc/systemd/system/regular-reboot.timer; enabled; preset: enabled)
     Active: active (waiting) since Wed 2024-03-13 01:54:52 EDT; 1 week 4 days ago
    Trigger: Fri 2024-04-12 12:24:42 EDT; 2 weeks 4 days left
   Triggers:   regular-reboot.service
Mar 13 01:54:52 dorfl systemd[1]: Started regular-reboot.timer - Reboot on a Regular Basis.

Sidenote: Replacing all Cron Jobs with systemd Timers More generally, I ve now replaced all cronjobs on my personal systems with systemd timer units, mostly because I can now actually track failures via prometheus-node-exporter. There are plenty of ways to hack in cron support to the node exporter, but just moving to systemd units provides both support for tracking failure and logging, both of which make system administration much easier when things inevitably go wrong.

systemd-cron An alternative to converting everything by hand, if you happen to have a lot of cronjobs is systemd-cron. It will make each crontab and /etc/cron.* directory into automatic service and timer units. Thanks to Alexandre Detiste for letting me know about this project. I have few enough cron jobs that I ve already converted, but for anyone looking at a large number of jobs to convert you ll want to check it out!

Stage Three: Monitor that it s working The final step here is confirm that these units actually work, beyond just firing regularly. I now have the following rule in my prometheus-alertmanager rules:
  - alert: UptimeTooHigh
    expr: (time() - node_boot_time_seconds job="node" ) / 86400 > 35
    annotations:
      summary: "Instance  Has Been Up Too Long!"
      description: "Instance  Has Been Up Too Long!"
This will trigger an alert anytime that I have a machine up for more than 35 days. This actually helped me track down one machine that I had forgotten to set up this new unit on4.

Not everything needs to scale Is It Worth The Time One of the most common fallacies programmers fall into is that we will jump to automating a solution before we stop and figure out how much time it would even save. In taking a slow improvement route to solve this problem for myself, I ve managed not to invest too much time5 in worrying about this but also achieved a meaningful improvement beyond my first approach of doing it all by hand.
  1. You could also add a line to /etc/crontab or drop a script into /etc/cron.monthly depending on your system.
  2. Why once a month? Mostly to avoid regular disruptions, but still be reasonably timely on updates.
  3. If you re looking to understand the cron time format I recommend crontab guru.
  4. In the long term I really should set up something like ansible to automatically push fleetwide changes like this but with fewer machines than fingers this seems like overkill.
  5. Of course by now writing about it, I ve probably doubled the amount of time I ve spent thinking about this topic but oh well

18 March 2024

Simon Josefsson: Apt archive mirrors in Git-LFS

My effort to improve transparency and confidence of public apt archives continues. I started to work on this in Apt Archive Transparency in which I mention the debdistget project in passing. Debdistget is responsible for mirroring index files for some public apt archives. I ve realized that having a publicly auditable and preserved mirror of the apt repositories is central to being able to do apt transparency work, so the debdistget project has become more central to my project than I thought. Currently I track Trisquel, PureOS, Gnuinos and their upstreams Ubuntu, Debian and Devuan. Debdistget download Release/Package/Sources files and store them in a git repository published on GitLab. Due to size constraints, it uses two repositories: one for the Release/InRelease files (which are small) and one that also include the Package/Sources files (which are large). See for example the repository for Trisquel release files and the Trisquel package/sources files. Repositories for all distributions can be found in debdistutils archives GitLab sub-group. The reason for splitting into two repositories was that the git repository for the combined files become large, and that some of my use-cases only needed the release files. Currently the repositories with packages (which contain a couple of months worth of data now) are 9GB for Ubuntu, 2.5GB for Trisquel/Debian/PureOS, 970MB for Devuan and 450MB for Gnuinos. The repository size is correlated to the size of the archive (for the initial import) plus the frequency and size of updates. Ubuntu s use of Apt Phased Updates (which triggers a higher churn of Packages file modifications) appears to be the primary reason for its larger size. Working with large Git repositories is inefficient and the GitLab CI/CD jobs generate quite some network traffic downloading the git repository over and over again. The most heavy user is the debdistdiff project that download all distribution package repositories to do diff operations on the package lists between distributions. The daily job takes around 80 minutes to run, with the majority of time is spent on downloading the archives. Yes I know I could look into runner-side caching but I dislike complexity caused by caching. Fortunately not all use-cases requires the package files. The debdistcanary project only needs the Release/InRelease files, in order to commit signatures to the Sigstore and Sigsum transparency logs. These jobs still run fairly quickly, but watching the repository size growth worries me. Currently these repositories are at Debian 440MB, PureOS 130MB, Ubuntu/Devuan 90MB, Trisquel 12MB, Gnuinos 2MB. Here I believe the main size correlation is update frequency, and Debian is large because I track the volatile unstable. So I hit a scalability end with my first approach. A couple of months ago I solved this by discarding and resetting these archival repositories. The GitLab CI/CD jobs were fast again and all was well. However this meant discarding precious historic information. A couple of days ago I was reaching the limits of practicality again, and started to explore ways to fix this. I like having data stored in git (it allows easy integration with software integrity tools such as GnuPG and Sigstore, and the git log provides a kind of temporal ordering of data), so it felt like giving up on nice properties to use a traditional database with on-disk approach. So I started to learn about Git-LFS and understanding that it was able to handle multi-GB worth of data that looked promising. Fairly quickly I scripted up a GitLab CI/CD job that incrementally update the Release/Package/Sources files in a git repository that uses Git-LFS to store all the files. The repository size is now at Ubuntu 650kb, Debian 300kb, Trisquel 50kb, Devuan 250kb, PureOS 172kb and Gnuinos 17kb. As can be expected, jobs are quick to clone the git archives: debdistdiff pipelines went from a run-time of 80 minutes down to 10 minutes which more reasonable correlate with the archive size and CPU run-time. The LFS storage size for those repositories are at Ubuntu 15GB, Debian 8GB, Trisquel 1.7GB, Devuan 1.1GB, PureOS/Gnuinos 420MB. This is for a couple of days worth of data. It seems native Git is better at compressing/deduplicating data than Git-LFS is: the combined size for Ubuntu is already 15GB for a couple of days data compared to 8GB for a couple of months worth of data with pure Git. This may be a sub-optimal implementation of Git-LFS in GitLab but it does worry me that this new approach will be difficult to scale too. At some level the difference is understandable, Git-LFS probably store two different Packages files around 90MB each for Trisquel as two 90MB files, but native Git would store it as one compressed version of the 90MB file and one relatively small patch to turn the old files into the next file. So the Git-LFS approach surprisingly scale less well for overall storage-size. Still, the original repository is much smaller, and you usually don t have to pull all LFS files anyway. So it is net win. Throughout this work, I kept thinking about how my approach relates to Debian s snapshot service. Ultimately what I would want is a combination of these two services. To have a good foundation to do transparency work I would want to have a collection of all Release/Packages/Sources files ever published, and ultimately also the source code and binaries. While it makes sense to start on the latest stable releases of distributions, this effort should scale backwards in time as well. For reproducing binaries from source code, I need to be able to securely find earlier versions of binary packages used for rebuilds. So I need to import all the Release/Packages/Sources packages from snapshot into my repositories. The latency to retrieve files from that server is slow so I haven t been able to find an efficient/parallelized way to download the files. If I m able to finish this, I would have confidence that my new Git-LFS based approach to store these files will scale over many years to come. This remains to be seen. Perhaps the repository has to be split up per release or per architecture or similar. Another factor is storage costs. While the git repository size for a Git-LFS based repository with files from several years may be possible to sustain, the Git-LFS storage size surely won t be. It seems GitLab charges the same for files in repositories and in Git-LFS, and it is around $500 per 100GB per year. It may be possible to setup a separate Git-LFS backend not hosted at GitLab to serve the LFS files. Does anyone know of a suitable server implementation for this? I had a quick look at the Git-LFS implementation list and it seems the closest reasonable approach would be to setup the Gitea-clone Forgejo as a self-hosted server. Perhaps a cloud storage approach a la S3 is the way to go? The cost to host this on GitLab will be manageable for up to ~1TB ($5000/year) but scaling it to storing say 500TB of data would mean an yearly fee of $2.5M which seems like poor value for the money. I realized that ultimately I would want a git repository locally with the entire content of all apt archives, including their binary and source packages, ever published. The storage requirements for a service like snapshot (~300TB of data?) is today not prohibitly expensive: 20TB disks are $500 a piece, so a storage enclosure with 36 disks would be around $18.000 for 720TB and using RAID1 means 360TB which is a good start. While I have heard about ~TB-sized Git-LFS repositories, would Git-LFS scale to 1PB? Perhaps the size of a git repository with multi-millions number of Git-LFS pointer files will become unmanageable? To get started on this approach, I decided to import a mirror of Debian s bookworm for amd64 into a Git-LFS repository. That is around 175GB so reasonable cheap to host even on GitLab ($1000/year for 200GB). Having this repository publicly available will make it possible to write software that uses this approach (e.g., porting debdistreproduce), to find out if this is useful and if it could scale. Distributing the apt repository via Git-LFS would also enable other interesting ideas to protecting the data. Consider configuring apt to use a local file:// URL to this git repository, and verifying the git checkout using some method similar to Guix s approach to trusting git content or Sigstore s gitsign. A naive push of the 175GB archive in a single git commit ran into pack size limitations: remote: fatal: pack exceeds maximum allowed size (4.88 GiB) however breaking up the commit into smaller commits for parts of the archive made it possible to push the entire archive. Here are the commands to create this repository: git init
git lfs install
git lfs track 'dists/**' 'pool/**'
git add .gitattributes
git commit -m"Add Git-LFS track attributes." .gitattributes
time debmirror --method=rsync --host ftp.se.debian.org --root :debian --arch=amd64 --source --dist=bookworm,bookworm-updates --section=main --verbose --diff=none --keyring /usr/share/keyrings/debian-archive-keyring.gpg --ignore .git .
git add dists project
git commit -m"Add." -a
git remote add origin git@gitlab.com:debdistutils/archives/debian/mirror.git
git push --set-upstream origin --all
for d in pool//; do
echo $d;
time git add $d;
git commit -m"Add $d." -a
git push
done
The resulting repository size is around 27MB with Git LFS object storage around 174GB. I think this approach would scale to handle all architectures for one release, but working with a single git repository for all releases for all architectures may lead to a too large git repository (>1GB). So maybe one repository per release? These repositories could also be split up on a subset of pool/ files, or there could be one repository per release per architecture or sources. Finally, I have concerns about using SHA1 for identifying objects. It seems both Git and Debian s snapshot service is currently using SHA1. For Git there is SHA-256 transition and it seems GitLab is working on support for SHA256-based repositories. For serious long-term deployment of these concepts, it would be nice to go for SHA256 identifiers directly. Git-LFS already uses SHA256 but Git internally uses SHA1 as does the Debian snapshot service. What do you think? Happy Hacking!

11 March 2024

Joachim Breitner: Convenient sandboxed development environment

I like using one machine and setup for everything, from serious development work to hobby projects to managing my finances. This is very convenient, as often the lines between these are blurred. But it is also scary if I think of the large number of people who I have to trust to not want to extract all my personal data. Whenever I run a cabal install, or a fun VSCode extension gets updated, or anything like that, I am running code that could be malicious or buggy. In a way it is surprising and reassuring that, as far as I can tell, this commonly does not happen. Most open source developers out there seem to be nice and well-meaning, after all.

Convenient or it won t happen Nevertheless I thought I should do something about this. The safest option would probably to use dedicated virtual machines for the development work, with very little interaction with my main system. But knowing me, that did not seem likely to happen, as it sounded like a fair amount of hassle. So I aimed for a viable compromise between security and convenient, and one that does not get too much in the way of my current habits. For instance, it seems desirable to have the project files accessible from my unconstrained environment. This way, I could perform certain actions that need access to secret keys or tokens, but are (unlikely) to run code (e.g. git push, git pull from private repositories, gh pr create) from the outside , and the actual build environment can do without access to these secrets. The user experience I thus want is a quick way to enter a development environment where I can do most of the things I need to do while programming (network access, running command line and GUI programs), with access to the current project, but without access to my actual /home directory. I initially followed the blog post Application Isolation using NixOS Containers by Marcin Sucharski and got something working that mostly did what I wanted, but then a colleague pointed out that tools like firejail can achieve roughly the same with a less global setup. I tried to use firejail, but found it to be a bit too inflexible for my particular whims, so I ended up writing a small wrapper around the lower level sandboxing tool https://github.com/containers/bubblewrap.

Selective bubblewrapping This script, called dev and included below, builds a new filesystem namespace with minimal /proc and /dev directories, it s own /tmp directories. It then binds-mound some directories to make the host s NixOS system available inside the container (/bin, /usr, the nix store including domain socket, stuff for OpenGL applications). My user s home directory is taken from ~/.dev-home and some configuration files are bind-mounted for convenient sharing. I intentionally don t share most of the configuration for example, a direnv enable in the dev environment should not affect the main environment. The X11 socket for graphical applications and the corresponding .Xauthority file is made available. And finally, if I run dev in a project directory, this project directory is bind mounted writable, and the current working directory is preserved. The effect is that I can type dev on the command line to enter dev mode rather conveniently. I can run development tools, including graphical ones like VSCode, and especially the latter with its extensions is part of the sandbox. To do a git push I either exit the development environment (Ctrl-D) or open a separate terminal. Overall, the inconvenience of switching back and forth seems worth the extra protection. Clearly, isn t going to hold against a determined and maybe targeted attacker (e.g. access to the X11 and the nix daemon socket can probably be used to escape easily). But I hope it will help against a compromised dev dependency that just deletes or exfiltrates data, like keys or passwords, from the usual places in $HOME.

Rough corners There is more polishing that could be done.
  • In particular, clicking on a link inside VSCode in the container will currently open Firefox inside the container, without access to my settings and cookies etc. Ideally, links would be opened in the Firefox running outside. This is a problem that has a solution in the world of applications that are sandboxed with Flatpak, and involves a bunch of moving parts (a xdg-desktop-portal user service, a filtering dbus proxy, exposing access to that proxy in the container). I experimented with that for a bit longer than I should have, but could not get it to work to satisfaction (even without a container involved, I could not get xdg-desktop-portal to heed my default browser settings ). For now I will live with manually copying and pasting URLs, we ll see how long this lasts.
  • With this setup (and unlike the NixOS container setup I tried first), the same applications are installed inside and outside. It might be useful to separate the set of installed programs: There is simply no point in running evolution or firefox inside the container, and if I do not even have VSCode or cabal available outside, so that it s less likely that I forget to enter dev before using these tools. It shouldn t be too hard to cargo-cult some of the NixOS Containers infrastructure to be able to have a separate system configuration that I can manage as part of my normal system configuration and make available to bubblewrap here.
So likely I will refine this some more over time. Or get tired of typing dev and going back to what I did before

The script
The dev script (at the time of writing)

9 March 2024

Reproducible Builds: Reproducible Builds in February 2024

Welcome to the February 2024 report from the Reproducible Builds project! In our reports, we try to outline what we have been up to over the past month as well as mentioning some of the important things happening in software supply-chain security.

Reproducible Builds at FOSDEM 2024 Core Reproducible Builds developer Holger Levsen presented at the main track at FOSDEM on Saturday 3rd February this year in Brussels, Belgium. However, that wasn t the only talk related to Reproducible Builds. However, please see our comprehensive FOSDEM 2024 news post for the full details and links.

Maintainer Perspectives on Open Source Software Security Bernhard M. Wiedemann spotted that a recent report entitled Maintainer Perspectives on Open Source Software Security written by Stephen Hendrick and Ashwin Ramaswami of the Linux Foundation sports an infographic which mentions that 56% of [polled] projects support reproducible builds .

Mailing list highlights From our mailing list this month:

Distribution work In Debian this month, 5 reviews of Debian packages were added, 22 were updated and 8 were removed this month adding to Debian s knowledge about identified issues. A number of issue types were updated as well. [ ][ ][ ][ ] In addition, Roland Clobus posted his 23rd update of the status of reproducible ISO images on our mailing list. In particular, Roland helpfully summarised that all major desktops build reproducibly with bullseye, bookworm, trixie and sid provided they are built for a second time within the same DAK run (i.e. [within] 6 hours) and that there will likely be further work at a MiniDebCamp in Hamburg. Furthermore, Roland also responded in-depth to a query about a previous report
Fedora developer Zbigniew J drzejewski-Szmek announced a work-in-progress script called fedora-repro-build that attempts to reproduce an existing package within a koji build environment. Although the projects README file lists a number of fields will always or almost always vary and there is a non-zero list of other known issues, this is an excellent first step towards full Fedora reproducibility.
Jelle van der Waa introduced a new linter rule for Arch Linux packages in order to detect cache files leftover by the Sphinx documentation generator which are unreproducible by nature and should not be packaged. At the time of writing, 7 packages in the Arch repository are affected by this.
Elsewhere, Bernhard M. Wiedemann posted another monthly update for his work elsewhere in openSUSE.

diffoscope diffoscope is our in-depth and content-aware diff utility that can locate and diagnose reproducibility issues. This month, Chris Lamb made a number of changes such as uploading versions 256, 257 and 258 to Debian and made the following additional changes:
  • Use a deterministic name instead of trusting gpg s use-embedded-filenames. Many thanks to Daniel Kahn Gillmor dkg@debian.org for reporting this issue and providing feedback. [ ][ ]
  • Don t error-out with a traceback if we encounter struct.unpack-related errors when parsing Python .pyc files. (#1064973). [ ]
  • Don t try and compare rdb_expected_diff on non-GNU systems as %p formatting can vary, especially with respect to MacOS. [ ]
  • Fix compatibility with pytest 8.0. [ ]
  • Temporarily fix support for Python 3.11.8. [ ]
  • Use the 7zip package (over p7zip-full) after a Debian package transition. (#1063559). [ ]
  • Bump the minimum Black source code reformatter requirement to 24.1.1+. [ ]
  • Expand an older changelog entry with a CVE reference. [ ]
  • Make test_zip black clean. [ ]
In addition, James Addison contributed a patch to parse the headers from the diff(1) correctly [ ][ ] thanks! And lastly, Vagrant Cascadian pushed updates in GNU Guix for diffoscope to version 255, 256, and 258, and updated trydiffoscope to 67.0.6.

reprotest reprotest is our tool for building the same source code twice in different environments and then checking the binaries produced by each build for any differences. This month, Vagrant Cascadian made a number of changes, including:
  • Create a (working) proof of concept for enabling a specific number of CPUs. [ ][ ]
  • Consistently use 398 days for time variation rather than choosing randomly and update README.rst to match. [ ][ ]
  • Support a new --vary=build_path.path option. [ ][ ][ ][ ]

Website updates There were made a number of improvements to our website this month, including:

Reproducibility testing framework The Reproducible Builds project operates a comprehensive testing framework (available at tests.reproducible-builds.org) in order to check packages and other artifacts for reproducibility. In February, a number of changes were made by Holger Levsen:
  • Debian-related changes:
    • Temporarily disable upgrading/bootstrapping Debian unstable and experimental as they are currently broken. [ ][ ]
    • Use the 64-bit amd64 kernel on all i386 nodes; no more 686 PAE kernels. [ ]
    • Add an Erlang package set. [ ]
  • Other changes:
    • Grant Jan-Benedict Glaw shell access to the Jenkins node. [ ]
    • Enable debugging for NetBSD reproducibility testing. [ ]
    • Use /usr/bin/du --apparent-size in the Jenkins shell monitor. [ ]
    • Revert reproducible nodes: mark osuosl2 as down . [ ]
    • Thanks again to Codethink, for they have doubled the RAM on our arm64 nodes. [ ]
    • Only set /proc/$pid/oom_score_adj to -1000 if it has not already been done. [ ]
    • Add the opemwrt-target-tegra and jtx task to the list of zombie jobs. [ ][ ]
Vagrant Cascadian also made the following changes:
  • Overhaul the handling of OpenSSH configuration files after updating from Debian bookworm. [ ][ ][ ]
  • Add two new armhf architecture build nodes, virt32z and virt64z, and insert them into the Munin monitoring. [ ][ ] [ ][ ]
In addition, Alexander Couzens updated the OpenWrt configuration in order to replace the tegra target with mpc85xx [ ], Jan-Benedict Glaw updated the NetBSD build script to use a separate $TMPDIR to mitigate out of space issues on a tmpfs-backed /tmp [ ] and Zheng Junjie added a link to the GNU Guix tests [ ]. Lastly, node maintenance was performed by Holger Levsen [ ][ ][ ][ ][ ][ ] and Vagrant Cascadian [ ][ ][ ][ ].

Upstream patches The Reproducible Builds project detects, dissects and attempts to fix as many currently-unreproducible packages as possible. We endeavour to send all of our patches upstream where appropriate. This month, we wrote a large number of such patches, including:

If you are interested in contributing to the Reproducible Builds project, please visit our Contribute page on our website. However, you can get in touch with us via:

2 March 2024

Ravi Dwivedi: Malaysia Trip

Last month, I had a trip to Malaysia and Thailand. I stayed for six days in each of the countries. The selection of these countries was due to both of them granting visa-free entry to Indian tourists for some time window. This post covers the Malaysia part and Thailand part will be covered in the next post. If you want to travel to any of these countries in the visa-free time period, I have written all the questions asked during immigration and at airports during this trip here which might be of help. I mostly stayed in Kuala Lumpur and went to places around it. Although before the trip, I planned to visit Ipoh and Cameron Highlands too, but could not cover it during the trip. I found planning a trip to Malaysia a little difficult. The country is divided into two main islands - Peninsular Malaysia and Borneo. Then there are more islands - Langkawi, Penang island, Perhentian and Redang Islands. Reaching those islands seemed a little difficult to plan and I wish to visit more places in my next Malaysia trip. My first day hostel was booked in Chinatown part of Kuala Lumpur, near Pasar Seni LRT station. As soon as I checked-in and entered my room, I met another Indian named Fletcher, and after that we accompanied each other in the trip. That day, we went to Muzium Negara and Little India. I realized that if you know the right places to buy what you want, Malaysia could be quite cheap. Malaysian currency is Malaysian Ringgit (MYR). 1 MYR is equal to 18 INR. For 2 MYR, you can get a good masala tea in Little India and it costs like 4-5 MYR for a masala dosa. The vegetarian food has good availability in Kuala Lumpur, thanks to the Tamil community. I also tried Mee Goreng, which was vegetarian, and I found it fine in terms of taste. When I checked about Mee Goreng on Wikipedia, I found out that it is unique to Indian immigrants in Malaysia (and neighboring countries) but you don t get it in India!
Mee Goreng, a dish made of noodles in Malaysia.
For the next day, Fletcher had planned a trip to Genting Highlands and pre booked everything. I also planned to join him but when we went to KL Sentral to take the bus, his bus tickets were sold out. I could take a bus at a different time, but decided to visit some other place for the day and cover Genting Highlands later. At the ticket counter, I met a family from Delhi and they wanted to go to Genting Highlands but due to not getting bus tickets for that day, they decided to buy a ticket for the next day and instead planned for Batu Caves that day. I joined them and went to Batu Caves. After returning from Batu Caves, we went our separate ways. I went back and took rest at my hostel and later went to Petronas Towers at night. Petronas Towers is the icon of Kuala Lumpur. Having a photo there was a must. I was at Petronas Towers at around 9 PM. Around that time, Fletcher came back from Genting Highlands and we planned to meet at KL Sentral to head for dinner.
Me at Petronas Towers.
We went back to the same place as the day before where I had Mee Goreng. This time we had dosa and a masala tea. Their masala tea from the last day was tasty and that s why I was looking for them in the first place. We also met a Malaysian family having Indian ancestry dining there and had a nice conversation. Then we went to a place to eat roti canai in Pasar Seni market. Roti canai is a popular non-vegetarian dish in Malaysia but I took the vegetarian version.
Photo with Malaysians.
The next day, we went to Berjaya Time Square shopping place which sells pretty cheap items for daily use and souveniers too. However, I bought souveniers from Petaling Street, which is in Chinatown. At night, we explored Bukit Bintang, which is the heart of Kuala Lumpur and is famous for its nightlife. After that, Fletcher went to Bangkok and I was in Malaysia for two more days. Next day, I went to Genting Highlands and took the cable car, which had awesome views. I came back to Kuala Lumpur by the night. The remaining day I just roamed around in Bukit Bintang. Then I took a flight for Bangkok on 7th Feb, which I will cover in the next post. In Malaysia, I met so many people from different countries - apart from people from Indian subcontinent, I met Syrians, Indonesians (Malaysia seems to be a popular destination for Indonesian tourists) and Burmese people. Meeting people from other cultures is an integral part of travel for me. My expenses for Food + Accommodation + Travel added to 10,000 INR for a week in Malaysia, while flight costs were: 13,000 INR (Delhi to Kuala Lumpur) + 10,000 INR (Kuala Lumpur to Bangkok) + 12,000 INR (Bangkok to Delhi). For OpenStreetMap users, good news is Kuala Lumpur is fairly well-mapped on OpenStreetMap.

Tips
  • I bought local SIM from a shop at KL Sentral station complex which had news in their name (I forgot the exact name and there are two shops having news in their name) and it was the cheapest option I could find. The SIM was 10 MYR for 5 GB data for a week. If you want to make calls too, then you need to spend extra 5 MYR.
  • 7-Eleven and KK Mart convenience stores are everywhere in the city and they are open all the time (24 hours a day). If you are a vegetarian, you can at least get some bread and cheese from there to eat.
  • A lot of people know English (and many - Indians, Pakistanis, Nepalis - know Hindi) in Kuala Lumpur, so I had no language problems most of the time.
  • For shopping on budget, you can go to Petaling Street, Berjaya Time Square or Bukit Bintang. In particular, there is a shop named I Love KL Gifts in Bukit Bintang which had very good prices. just near the metro/monorail stattion. Check out location of the shop on OpenStreetMap.

28 February 2024

Daniel Lange: Opencollective shutting down

Update 28.02.2024 19:45 CET: There is now a blog entry at https://blog.opencollective.com/open-collective-official-statement-ocf-dissolution/ trying to discern the legal entities in the Open Collective ecosystem and recommending potential ways forward.
Gee, there is nothing on their blog yet, but I just [28.02.2023 00:07 CET] received this email from Mike Strode, Program Officer at the Open Collective Foundation: Dear Daniel Lange, It is with a heavy heart that I'm writing today to inform you that the Board of Directors of the Open Collective Foundation (OCF) has made the difficult decision to dissolve OCF, effective December 31, 2024. We are proud of the work we have been able to do together. We have been honored to build community with you and the hundreds of other collectives hosted at the Open Collective Foundation. What you need to know: We are beginning a staged dissolution process that will allow our over 600 collectives the time to close or transition their work. Dissolving OCF will take many months, and involves settling all liabilities while spending down all funds in a legally compliant manner. Our priority is to support our collectives in navigating this change. We want to provide collectives the longest possible runway to wind down or transition their operations while we focus on the many legal and financial tasks associated with dissolving a nonprofit. March 15 is the last day to accept donations. You will have until September 30 to work with us to develop and implement a plan to spend down the money in your fund. Key dates are included at the bottom of this email. We know this is going to be difficult, and we will do everything we can to ease the transition for you. How we will support collectives: It remains our fiduciary responsibility to safeguard each collective's charitable assets and ensure funds are used solely for specified charitable purposes. We will be providing assistance and support to you, whether you choose to spend out and close down your collective or continue your work through another 501(c)(3) organization or fiscal sponsor. Unfortunately, we had to say goodbye to several of our colleagues today as we pare down our core staff to reduce costs. I will be staying on staff to support collectives through this transition, along with Wayne Kleppe, our Finance Administrator. What led to this decision: From day one, OCF was committed to experimentation and innovation. We were dedicated to finding new ways to open up the nonprofit space, making it easier for people to raise and access funding so they can do good in their communities. OCF was created by Open Collective Inc. (OCI), a company formed in 2015 with the goal of "enabling groups to quickly set up a collective, raise funds and manage them transparently." Soon after being founded by OCI, OCF went through a period of rapid growth. We responded to increased demand arising from the COVID-19 pandemic without taking the time to establish the appropriate systems and infrastructure to sustain that growth. Unfortunately, over the past year, we have learned that Open Collective Foundation's business model is not sustainable with the number of complex services we have offered and the fees we pay to the Open Collective Inc. tech platform. In late 2023, we made the decision to pause accepting new collectives in order to create space for us to address the issues. Unfortunately, it became clear that it would not be financially feasible to make the necessary corrections, and we determined that OCF is not viable. What's next: We know this news will raise questions for many of our collectives. We will be making space for questions and reactions in the coming weeks. In the meantime, we have developed this FAQ which we will keep updated as more questions come in. What you need to do next: Dates to know: In Care & Accompaniment,
Mike Strode
Program Officer
Open Collective Foundation Our mailing address has changed! We are now located at 440 N. Barranca Avenue #3717, Covina, CA 91723, USA

11 February 2024

Freexian Collaborators: Debian Contributions: Upcoming Improvements to Salsa CI, /usr-move, and more! (by Utkarsh Gupta)

Contributing to Debian is part of Freexian s mission. This article covers the latest achievements of Freexian and their collaborators. All of this is made possible by organizations subscribing to our Long Term Support contracts and consulting services.

Upcoming Improvements to Salsa CI, by Santiago Ruano Rinc n Santiago started picking up the work made by Outreachy Intern, Enock Kashada (a big thanks to him!), to solve some long-standing issues in Salsa CI. Currently, the first job in a Salsa CI pipeline is the extract-source job, used to produce a debianize source tree of the project. This job was introduced to make it possible to build the projects on different architectures, on the subsequent build jobs. However, that extract-source approach is sub-optimal: not only it increases the execution time of the pipeline by some minutes, but also projects whose source tree is too large are not able to use the pipeline. The debianize source tree is passed as an artifact to the build jobs, and for those large projects, the size of their source tree exceeds the Salsa s limits. This is specific issue is documented as issue #195, and the proposed solution is to get rid of the extract-source job, relying on sbuild in the very build job (see issue #296). Switching to sbuild would also help to improve the build source job, solving issues such as #187 and #298. The current work-in-progress is very preliminary, but it has already been possible to run the build (amd64), build-i386 and build-source job using sbuild with the unshare mode. The image on the right shows a pipeline that builds grep. All the test jobs use the artifacts of the new build job. There is a lot of remaining work, mainly making the integration with ccache work. This change could break some things, it will also be important to test how the new pipeline works with complex projects. Also, thanks to Emmanuel Arias, we are proposing a Google Summer of Code 2024 project to improve Salsa CI. As part of the ongoing work in preparation for the GSoC 2024 project, Santiago has proposed a merge request to make more efficient how contributors can test their changes on the Salsa CI pipeline.

/usr-move, by Helmut Grohne In January, we sent most of the moving patches for the set of packages involved with debootstrap. Notably missing is glibc, which turns out harder than anticipated via dumat, because it has Conflicts between different architectures, which dumat does not analyze. Patches for diversion mitigations have been updated in a way to not exhibit any loss anymore. The main change here is that packages which are being diverted now support the diverting packages in transitioning their diversions. We also supported a few packages with non-trivial changes such as netplan.io. dumat has been enhanced to better support derivatives such as Ubuntu.

Miscellaneous contributions
  • Python 3.12 migration trundles on. Stefano Rivera helped port several new packages to support 3.12.
  • Stefano updated the Sphinx configuration of DebConf Video Team s documentation, which was broken by Sphinx 7.
  • Stefano published the videos from the Cambridge MiniDebConf to YouTube and PeerTube.
  • DebConf 24 planning has begun, and Stefano & Utkarsh have started work on this.
  • Utkarsh re-sponsored the upload of golang-github-prometheus-community-pgbouncer-exporter for Lena.
  • Colin Watson added Incus support to autopkgtest.
  • Colin discovered Perl::Critic and used it to tidy up some poor practices in several of his packages, including debconf.
  • Colin did some overdue debconf maintenance, mainly around tidying up error message handling in several places (1, 2, 3).
  • Colin figured out how to update the mirror size documentation in debmirror, last updated in 2010. It should now be much easier to keep it up to date regularly.
  • Colin issued a man-db buster update to clean up some irritations due to strict sandboxing.
  • Thorsten Alteholz adopted two more packages, magicfilter and ifhp, for the debian-printing team. Those packages are the last ones of the latest round of adoptions to preserve the old printing protocol within Debian. If you know of other packages that should be retained, please don t hesitate to contact Thorsten.
  • Enrico participated in /usr-merge discussions with Helmut.
  • Helmut sent patches for 16 cross build failures.
  • Helmut supported Matthias Klose (not affiliated with Freexian) with adding -for-host support to gcc-defaults.
  • Helmut uploaded dput-ng enabling dcut migrate and merging two MRs of Ben Hutchings.
  • Santiago took part in the discussions relating to the EU Cyber Resilience Act (CRA) and the Debian public statement that was published last year. He participated in a meeting with Members of the European Parliament (MEPs), Marcel Kolaja and Karen Melchior, and their teams to clarify some points about the impact of the CRA and Debian and downstream projects, and the improvements in the last version of the proposed regulation.

8 February 2024

Dirk Eddelbuettel: RcppArmadillo 0.12.8.0.0 on CRAN: New Upstream, Interface Polish

armadillo image Armadillo is a powerful and expressive C++ template library for linear algebra and scientific computing. It aims towards a good balance between speed and ease of use, has a syntax deliberately close to Matlab, and is useful for algorithm development directly in C++, or quick conversion of research code into production environments. RcppArmadillo integrates this library with the R environment and language and is widely used by (currently) 1119 other packages on CRAN, downloaded 32.5 million times (per the partial logs from the cloud mirrors of CRAN), and the CSDA paper (preprint / vignette) by Conrad and myself has been cited 575 times according to Google Scholar. This release brings a new (stable) upstream (minor) release Armadillo 12.8.0 prepared by Conrad two days ago. We, as usual, prepared a release candidate which we tested against the over 1100 CRAN packages using RcppArmadillo. This found no issues, which was confirmed by CRAN once we uploaded and so it arrived as a new release today in a fully automated fashion. We also made a small change that had been prepared by GitHub issue #400: a few internal header files that were cluttering the top-level of the include directory have been moved to internal directories. The standard header is of course unaffected, and the set of full / light / lighter / lightest headers (matching we did a while back in Rcpp) also continue to work as one expects. This change was also tested in a full reverse-dependency check in January but had not been released to CRAN yet. The set of changes since the last CRAN release follows.

Changes in RcppArmadillo version 0.12.8.0.0 (2024-02-06)
  • Upgraded to Armadillo release 12.8.0 (Cortisol Injector)
    • Faster detection of symmetric expressions by pinv() and rank()
    • Expanded shift() to handle sparse matrices
    • Expanded conv_to for more flexible conversions between sparse and dense matrices
    • Added cbrt()
    • More compact representation of integers when saving matrices in CSV format
  • Five non-user facing top-level include files have been removed (#432 closing #400 and building on #395 and #396)

Courtesy of my CRANberries, there is a diffstat report relative to previous release. More detailed information is on the RcppArmadillo page. Questions, comments etc should go to the rcpp-devel mailing list off the Rcpp R-Forge page. If you like this or other open-source work I do, you can sponsor me at GitHub.

This post by Dirk Eddelbuettel originated on his Thinking inside the box blog. Please report excessive re-aggregation in third-party for-profit settings.

1 February 2024

Russ Allbery: Review: System Collapse

Review: System Collapse, by Martha Wells
Series: Murderbot Diaries #7
Publisher: Tordotcom
Copyright: 2023
ISBN: 1-250-82698-5
Format: Kindle
Pages: 245
System Collapse is the second Murderbot novel. Including the novellas, it's the 7th in the series. Unlike Fugitive Telemetry, the previous novella that was out of chronological order, this is the direct sequel to Network Effect. A very direct sequel; it picks up just a few days after the previous novel ended. Needless to say, you should not start here. I was warned by other people and therefore re-read Network Effect immediately before reading System Collapse. That was an excellent idea, since this novel opens with a large cast, no dramatis personae, not much in the way of a plot summary, and a lot of emotional continuity from the previous novel. I would grumble about this more, like I have in other reviews, but I thoroughly enjoyed re-reading Network Effect and appreciated the excuse.
ART-drone said, I wouldn t recommend it. I lack a sense of proportional response. I don t advise engaging with me on any level.
Saying much about the plot of this book without spoiling Network Effect and the rest of the series is challenging. Murderbot is suffering from the aftereffects of the events of the previous book more than it expected or would like to admit. It and its humans are in the middle of a complicated multi-way negotiation with some locals, who the corporates are trying to exploit. One of the difficulties in that negotiation is getting people to believe that the corporations are as evil as they actually are, a plot element that has a depressing amount in common with current politics. Meanwhile, Murderbot is trying to keep everyone alive. I loved Network Effect, but that was primarily for the social dynamics. The planet that was central to the novel was less interesting, so another (short) novel about the same planet was a bit of a disappointment. This does give Wells a chance to show in more detail what Murderbot's new allies have been up to, but there is a lot of speculative exploration and detailed descriptions of underground tunnels that I found less compelling than the relationship dynamics of the previous book. (Murderbot, on the other hand, would much prefer exploring creepy abandoned tunnels to talking about its feelings.) One of the things this series continues to do incredibly well, though, is take non-human intelligence seriously in a world where the humans mostly don't. It perfectly fills a gap between Star Wars, where neither the humans nor the story take non-human intelligences seriously (hence the creepy slavery vibes as soon as you start paying attention to droids), and the Culture, where both humans and the story do. The corporates (the bad guys in this series) treat non-human intelligences the way Star Wars treats droids. The good guys treat Murderbot mostly like a strange human, which is better but still wrong, and still don't notice the numerous other machine intelligences. But Wells, as the author, takes all of the non-human characters seriously, which means there are complex and fascinating relationships happening at a level of the story that the human characters are mostly unaware of. I love that Murderbot rarely bothers to explain; if the humans are too blinkered to notice, that's their problem. About halfway into the story, System Collapse hits its stride, not coincidentally at the point where Murderbot befriends some new computers. The rest of the book is great. This was not as good as Network Effect. There is a bit less competence porn at the start, and although that's for good in-story reasons I still missed it. Murderbot's redaction of things it doesn't want to talk about got a bit annoying before it finally resolved. And I was not sufficiently interested in this planet to want to spend two novels on it, at least without another major revelation that didn't come. But it's still a Murderbot novel, which means it has the best first-person narrative voice I've ever read, some great moments, and possibly the most compelling and varied presentation of computer intelligence in science fiction at the moment.
There was no feed ID, but AdaCol2 supplied the name Lucia and when I asked it for more info, the gender signifier bb (which didn t translate) and he/him pronouns. (I asked because the humans would bug me for the information; I was as indifferent to human gender as it was possible to be without being unconscious.)
This is not a series to read out of order, but if you have read this far, you will continue to be entertained. You don't need me to tell you this nearly everyone reviewing science fiction is saying it but this series is great and you should read it. Rating: 8 out of 10

31 January 2024

Bits from Debian: New Debian Developers and Maintainers (November and December 2023)

The following contributors got their Debian Developer accounts in the last two months: The following contributor was added as Debian Maintainer in the last two months: Congratulations!

22 January 2024

Paul Tagliamonte: Writing a simulator to check phased array beamforming

Interested in future updates? Follow me on mastodon at @paul@soylent.green. Posts about hz.tools will be tagged #hztools.

If you're on the Fediverse, I'd very much appreciate boosts on my toot!
While working on hz.tools, I started to move my beamforming code from 2-D (meaning, beamforming to some specific angle on the X-Y plane for waves on the X-Y plane) to 3-D. I ll have more to say about that once I get around to publishing the code as soon as I m sure it s not completely wrong, but in the meantime I decided to write a simple simulator to visually check the beamformer against the textbooks. The results were pretty rad, so I figured I d throw together a post since it s interesting all on its own outside of beamforming as a general topic. I figured I d write this in Rust, since I ve been using Rust as my primary language over at zoo, and it s a good chance to learn the language better.
This post has some large GIFs

It make take a little bit to load depending on your internet connection. Sorry about that, I'm not clever enough to do better without doing tons of complex engineering work. They may be choppy while they load or something. I tried to compress an ensmall them, so if they're loaded but fuzzy, click on them to load a slightly larger version.
This post won t cover the basics of how phased arrays work or the specifics of calculating the phase offsets for each antenna, but I ll dig into how I wrote a simple simulator and how I wound up checking my phase offsets to generate the renders below.

Assumptions I didn t want to build a general purpose RF simulator, anything particularly generic, or something that would solve for any more than the things right in front of me. To do this as simply (and quickly all this code took about a day to write, including the beamforming math) I had to reduce the amount of work in front of me. Given that I was concerend with visualizing what the antenna pattern would look like in 3-D given some antenna geometry, operating frequency and configured beam, I made the following assumptions: All anetnnas are perfectly isotropic they receive a signal that is exactly the same strength no matter what direction the signal originates from. There s a single point-source isotropic emitter in the far-field (I modeled this as being 1 million meters away 1000 kilometers) of the antenna system. There is no noise, multipath, loss or distortion in the signal as it travels through space. Antennas will never interfere with each other.

2-D Polar Plots The last time I wrote something like this, I generated 2-D GIFs which show a radiation pattern, not unlike the polar plots you d see on a microphone. These are handy because it lets you visualize what the directionality of the antenna looks like, as well as in what direction emissions are captured, and in what directions emissions are nulled out. You can see these plots on spec sheets for antennas in both 2-D and 3-D form. Now, let s port the 2-D approach to 3-D and see how well it works out.

Writing the 3-D simulator As an EM wave travels through free space, the place at which you sample the wave controls that phase you observe at each time-step. This means, assuming perfectly synchronized clocks, a transmitter and receiver exactly one RF wavelength apart will observe a signal in-phase, but a transmitter and receiver a half wavelength apart will observe a signal 180 degrees out of phase. This means that if we take the distance between our point-source and antenna element, divide it by the wavelength, we can use the fractional part of the resulting number to determine the phase observed. If we multiply that number (in the range of 0 to just under 1) by tau, we can generate a complex number by taking the cos and sin of the multiplied phase (in the range of 0 to tau), assuming the transmitter is emitting a carrier wave at a static amplitude and all clocks are in perfect sync.
 let observed_phases: Vec<Complex> = antennas
.iter()
.map( antenna   
let distance = (antenna - tx).magnitude();
let distance = distance - (distance as i64 as f64);
((distance / wavelength) * TAU)
 )
.map( phase  Complex(phase.cos(), phase.sin()))
.collect();
At this point, given some synthetic transmission point and each antenna, we know what the expected complex sample would be at each antenna. At this point, we can adjust the phase of each antenna according to the beamforming phase offset configuration, and add up every sample in order to determine what the entire system would collectively produce a sample as.
 let beamformed_phases: Vec<Complex> = ...;
let magnitude = beamformed_phases
.iter()
.zip(observed_phases.iter())
.map( (beamformed, observed)  observed * beamformed)
.reduce( acc, el  acc + el)
.unwrap()
.abs();
Armed with this information, it s straight forward to generate some number of (Azimuth, Elevation) points to sample, generate a transmission point far away in that direction, resolve what the resulting Complex sample would be, take its magnitude, and use that to create an (x, y, z) point at (azimuth, elevation, magnitude). The color attached two that point is based on its distance from (0, 0, 0). I opted to use the Life Aquatic table for this one. After this process is complete, I have a point cloud of ((x, y, z), (r, g, b)) points. I wrote a small program using kiss3d to render point cloud using tons of small spheres, and write out the frames to a set of PNGs, which get compiled into a GIF. Now for the fun part, let s take a look at some radiation patterns!

1x4 Phased Array The first configuration is a phased array where all the elements are in perfect alignment on the y and z axis, and separated by some offset in the x axis. This configuration can sweep 180 degrees (not the full 360), but can t be steared in elevation at all. Let s take a look at what this looks like for a well constructed 1x4 phased array: And now let s take a look at the renders as we play with the configuration of this array and make sure things look right. Our initial quarter-wavelength spacing is very effective and has some outstanding performance characteristics. Let s check to see that everything looks right as a first test. Nice. Looks perfect. When pointing forward at (0, 0), we d expect to see a torus, which we do. As we sweep between 0 and 360, astute observers will notice the pattern is mirrored along the axis of the antennas, when the beam is facing forward to 0 degrees, it ll also receive at 180 degrees just as strong. There s a small sidelobe that forms when it s configured along the array, but it also becomes the most directional, and the sidelobes remain fairly small.

Long compared to the wavelength (1 ) Let s try again, but rather than spacing each antenna of a wavelength apart, let s see about spacing each antenna 1 of a wavelength apart instead. The main lobe is a lot more narrow (not a bad thing!), but some significant sidelobes have formed (not ideal). This can cause a lot of confusion when doing things that require a lot of directional resolution unless they re compensated for.

Going from ( to 5 ) The last model begs the question - what do things look like when you separate the antennas from each other but without moving the beam? Let s simulate moving our antennas but not adjusting the configured beam or operating frequency. Very cool. As the spacing becomes longer in relation to the operating frequency, we can see the sidelobes start to form out of the end of the antenna system.

2x2 Phased Array The second configuration I want to try is a phased array where the elements are in perfect alignment on the z axis, and separated by a fixed offset in either the x or y axis by their neighbor, forming a square when viewed along the x/y axis. Let s take a look at what this looks like for a well constructed 2x2 phased array: Let s do the same as above and take a look at the renders as we play with the configuration of this array and see what things look like. This configuration should suppress the sidelobes and give us good performance, and even give us some amount of control in elevation while we re at it. Sweet. Heck yeah. The array is quite directional in the configured direction, and can even sweep a little bit in elevation, a definite improvement from the 1x4 above.

Long compared to the wavelength (1 ) Let s do the same thing as the 1x4 and take a look at what happens when the distance between elements is long compared to the frequency of operation say, 1 of a wavelength apart? What happens to the sidelobes given this spacing when the frequency of operation is much different than the physical geometry? Mesmerising. This is my favorate render. The sidelobes are very fun to watch come in and out of existence. It looks absolutely other-worldly.

Going from ( to 5 ) Finally, for completeness' sake, what do things look like when you separate the antennas from each other just as we did with the 1x4? Let s simulate moving our antennas but not adjusting the configured beam or operating frequency. Very very cool. The sidelobes wind up turning the very blobby cardioid into an electromagnetic dog toy. I think we ve proven to ourselves that using a phased array much outside its designed frequency of operation seems like a real bad idea.

Future Work Now that I have a system to test things out, I m a bit more confident that my beamforming code is close to right! I d love to push that code over the line and blog about it, since it s a really interesting topic on its own. Once I m sure the code involved isn t full of lies, I ll put it up on the hztools org, and post about it here and on mastodon.

20 January 2024

Niels Thykier: Making debputy: Writing declarative parsing logic

In this blog post, I will cover how debputy parses its manifest and the conceptual improvements I did to make parsing of the manifest easier. All instructions to debputy are provided via the debian/debputy.manifest file and said manifest is written in the YAML format. After the YAML parser has read the basic file structure, debputy does another pass over the data to extract the information from the basic structure. As an example, the following YAML file:
manifest-version: "0.1"
installations:
  - install:
      source: foo
      dest-dir: usr/bin
would be transformed by the YAML parser into a structure resembling:
 
  "manifest-version": "0.1",
  "installations": [
      
       "install":  
         "source": "foo",
         "dest-dir": "usr/bin",
        
      
  ]
 
This structure is then what debputy does a pass on to translate this into an even higher level format where the "install" part is translated into an InstallRule. In the original prototype of debputy, I would hand-write functions to extract the data that should be transformed into the internal in-memory high level format. However, it was quite tedious. Especially because I wanted to catch every possible error condition and report "You are missing the required field X at Y" rather than the opaque KeyError: X message that would have been the default. Beyond being tedious, it was also quite error prone. As an example, in debputy/0.1.4 I added support for the install rule and you should allegedly have been able to add a dest-dir: or an as: inside it. Except I crewed up the code and debputy was attempting to look up these keywords from a dict that could never have them. Hand-writing these parsers were so annoying that it demotivated me from making manifest related changes to debputy simply because I did not want to code the parsing logic. When I got this realization, I figured I had to solve this problem better. While reflecting on this, I also considered that I eventually wanted plugins to be able to add vocabulary to the manifest. If the API was "provide a callback to extract the details of whatever the user provided here", then the result would be bad.
  1. Most plugins would probably throw KeyError: X or ValueError style errors for quite a while. Worst case, they would end on my table because the user would have a hard time telling where debputy ends and where the plugins starts. "Best" case, I would teach debputy to say "This poor error message was brought to you by plugin foo. Go complain to them". Either way, it would be a bad user experience.
  2. This even assumes plugin providers would actually bother writing manifest parsing code. If it is that difficult, then just providing a custom file in debian might tempt plugin providers and that would undermine the idea of having the manifest be the sole input for debputy.
So beyond me being unsatisfied with the current situation, it was also clear to me that I needed to come up with a better solution if I wanted externally provided plugins for debputy. To put a bit more perspective on what I expected from the end result:
  1. It had to cover as many parsing errors as possible. An error case this code would handle for you, would be an error where I could ensure it sufficient degree of detail and context for the user.
  2. It should be type-safe / provide typing support such that IDEs/mypy could help you when you work on the parsed result.
  3. It had to support "normalization" of the input, such as
           # User provides
           - install: "foo"
           # Which is normalized into:
           - install:
               source: "foo"
4) It must be simple to tell  debputy  what input you expected.
At this point, I remembered that I had seen a Python (PYPI) package where you could give it a TypedDict and an arbitrary input (Sadly, I do not remember the name). The package would then validate the said input against the TypedDict. If the match was successful, you would get the result back casted as the TypedDict. If the match was unsuccessful, the code would raise an error for you. Conceptually, this seemed to be a good starting point for where I wanted to be. Then I looked a bit on the normalization requirement (point 3). What is really going on here is that you have two "schemas" for the input. One is what the programmer will see (the normalized form) and the other is what the user can input (the manifest form). The problem is providing an automatic normalization from the user input to the simplified programmer structure. To expand a bit on the following example:
# User provides
- install: "foo"
# Which is normalized into:
- install:
    source: "foo"
Given that install has the attributes source, sources, dest-dir, as, into, and when, how exactly would you automatically normalize "foo" (str) into source: "foo"? Even if the code filtered by "type" for these attributes, you would end up with at least source, dest-dir, and as as candidates. Turns out that TypedDict actually got this covered. But the Python package was not going in this direction, so I parked it here and started looking into doing my own. At this point, I had a general idea of what I wanted. When defining an extension to the manifest, the plugin would provide debputy with one or two definitions of TypedDict. The first one would be the "parsed" or "target" format, which would be the normalized form that plugin provider wanted to work on. For this example, lets look at an earlier version of the install-examples rule:
# Example input matching this typed dict.
#    
#       "source": ["foo"]
#       "into": ["pkg"]
#    
class InstallExamplesTargetFormat(TypedDict):
    # Which source files to install (dest-dir is fixed)
    sources: List[str]
    # Which package(s) that should have these files installed.
    into: NotRequired[List[str]]
In this form, the install-examples has two attributes - both are list of strings. On the flip side, what the user can input would look something like this:
# Example input matching this typed dict.
#    
#       "source": "foo"
#       "into": "pkg"
#    
#
class InstallExamplesManifestFormat(TypedDict):
    # Note that sources here is split into source (str) vs. sources (List[str])
    sources: NotRequired[List[str]]
    source: NotRequired[str]
    # We allow the user to write  into: foo  in addition to  into: [foo] 
    into: Union[str, List[str]]
FullInstallExamplesManifestFormat = Union[
    InstallExamplesManifestFormat,
    List[str],
    str,
]
The idea was that the plugin provider would use these two definitions to tell debputy how to parse install-examples. Pseudo-registration code could look something like:
def _handler(
    normalized_form: InstallExamplesTargetFormat,
) -> InstallRule:
    ...  # Do something with the normalized form and return an InstallRule.
concept_debputy_api.add_install_rule(
  keyword="install-examples",
  target_form=InstallExamplesTargetFormat,
  manifest_form=FullInstallExamplesManifestFormat,
  handler=_handler,
)
This was my conceptual target and while the current actual API ended up being slightly different, the core concept remains the same.
From concept to basic implementation Building this code is kind like swallowing an elephant. There was no way I would just sit down and write it from one end to the other. So the first prototype of this did not have all the features it has now. Spoiler warning, these next couple of sections will contain some Python typing details. When reading this, it might be helpful to know things such as Union[str, List[str]] being the Python type for either a str (string) or a List[str] (list of strings). If typing makes your head spin, these sections might less interesting for you. To build this required a lot of playing around with Python's introspection and typing APIs. My very first draft only had one "schema" (the normalized form) and had the following features:
  • Read TypedDict.__required_attributes__ and TypedDict.__optional_attributes__ to determine which attributes where present and which were required. This was used for reporting errors when the input did not match.
  • Read the types of the provided TypedDict, strip the Required / NotRequired markers and use basic isinstance checks based on the resulting type for str and List[str]. Again, used for reporting errors when the input did not match.
This prototype did not take a long (I remember it being within a day) and worked surprisingly well though with some poor error messages here and there. Now came the first challenge, adding the manifest format schema plus relevant normalization rules. The very first normalization I did was transforming into: Union[str, List[str]] into into: List[str]. At that time, source was not a separate attribute. Instead, sources was a Union[str, List[str]], so it was the only normalization I needed for all my use-cases at the time. There are two problems when writing a normalization. First is determining what the "source" type is, what the target type is and how they relate. The second is providing a runtime rule for normalizing from the manifest format into the target format. Keeping it simple, the runtime normalizer for Union[str, List[str]] -> List[str] was written as:
def normalize_into_list(x: Union[str, List[str]]) -> List[str]:
    return x if isinstance(x, list) else [x]
This basic form basically works for all types (assuming none of the types will have List[List[...]]). The logic for determining when this rule is applicable is slightly more involved. My current code is about 100 lines of Python code that would probably lose most of the casual readers. For the interested, you are looking for _union_narrowing in declarative_parser.py With this, when the manifest format had Union[str, List[str]] and the target format had List[str] the generated parser would silently map a string into a list of strings for the plugin provider. But with that in place, I had covered the basics of what I needed to get started. I was quite excited about this milestone of having my first keyword parsed without handwriting the parser logic (at the expense of writing a more generic parse-generator framework).
Adding the first parse hint With the basic implementation done, I looked at what to do next. As mentioned, at the time sources in the manifest format was Union[str, List[str]] and I considered to split into a source: str and a sources: List[str] on the manifest side while keeping the normalized form as sources: List[str]. I ended up committing to this change and that meant I had to solve the problem getting my parser generator to understand the situation:
# Map from
class InstallExamplesManifestFormat(TypedDict):
    # Note that sources here is split into source (str) vs. sources (List[str])
    sources: NotRequired[List[str]]
    source: NotRequired[str]
    # We allow the user to write  into: foo  in addition to  into: [foo] 
    into: Union[str, List[str]]
# ... into
class InstallExamplesTargetFormat(TypedDict):
    # Which source files to install (dest-dir is fixed)
    sources: List[str]
    # Which package(s) that should have these files installed.
    into: NotRequired[List[str]]
There are two related problems to solve here:
  1. How will the parser generator understand that source should be normalized and then mapped into sources?
  2. Once that is solved, the parser generator has to understand that while source and sources are declared as NotRequired, they are part of a exactly one of rule (since sources in the target form is Required). This mainly came down to extra book keeping and an extra layer of validation once the previous step is solved.
While working on all of this type introspection for Python, I had noted the Annotated[X, ...] type. It is basically a fake type that enables you to attach metadata into the type system. A very random example:
# For all intents and purposes,  foo  is a string despite all the  Annotated  stuff.
foo: Annotated[str, "hello world"] = "my string here"
The exciting thing is that you can put arbitrary details into the type field and read it out again in your introspection code. Which meant, I could add "parse hints" into the type. Some "quick" prototyping later (a day or so), I got the following to work:
# Map from
#      
#        "source": "foo"  # (or "sources": ["foo"])
#        "into": "pkg"
#      
class InstallExamplesManifestFormat(TypedDict):
    # Note that sources here is split into source (str) vs. sources (List[str])
    sources: NotRequired[List[str]]
    source: NotRequired[
        Annotated[
            str,
            DebputyParseHint.target_attribute("sources")
        ]
    ]
    # We allow the user to write  into: foo  in addition to  into: [foo] 
    into: Union[str, List[str]]
# ... into
#      
#        "source": ["foo"]
#        "into": ["pkg"]
#      
class InstallExamplesTargetFormat(TypedDict):
    # Which source files to install (dest-dir is fixed)
    sources: List[str]
    # Which package(s) that should have these files installed.
    into: NotRequired[List[str]]
Without me (as a plugin provider) writing a line of code, I can have debputy rename or "merge" attributes from the manifest form into the normalized form. Obviously, this required me (as the debputy maintainer) to write a lot code so other me and future plugin providers did not have to write it.
High level typing At this point, basic normalization between one mapping to another mapping form worked. But one thing irked me with these install rules. The into was a list of strings when the parser handed them over to me. However, I needed to map them to the actual BinaryPackage (for technical reasons). While I felt I was careful with my manual mapping, I knew this was exactly the kind of case where a busy programmer would skip the "is this a known package name" check and some user would typo their package resulting in an opaque KeyError: foo. Side note: "Some user" was me today and I was super glad to see debputy tell me that I had typoed a package name (I would have been more happy if I had remembered to use debputy check-manifest, so I did not have to wait through the upstream part of the build that happened before debhelper passed control to debputy...) I thought adding this feature would be simple enough. It basically needs two things:
  1. Conversion table where the parser generator can tell that BinaryPackage requires an input of str and a callback to map from str to BinaryPackage. (That is probably lie. I think the conversion table came later, but honestly I do remember and I am not digging into the git history for this one)
  2. At runtime, said callback needed access to the list of known packages, so it could resolve the provided string.
It was not super difficult given the existing infrastructure, but it did take some hours of coding and debugging. Additionally, I added a parse hint to support making the into conditional based on whether it was a single binary package. With this done, you could now write something like:
# Map from
class InstallExamplesManifestFormat(TypedDict):
    # Note that sources here is split into source (str) vs. sources (List[str])
    sources: NotRequired[List[str]]
    source: NotRequired[
        Annotated[
            str,
            DebputyParseHint.target_attribute("sources")
        ]
    ]
    # We allow the user to write  into: foo  in addition to  into: [foo] 
    into: Union[BinaryPackage, List[BinaryPackage]]
# ... into
class InstallExamplesTargetFormat(TypedDict):
    # Which source files to install (dest-dir is fixed)
    sources: List[str]
    # Which package(s) that should have these files installed.
    into: NotRequired[
        Annotated[
            List[BinaryPackage],
            DebputyParseHint.required_when_multi_binary()
        ]
    ]
Code-wise, I still had to check for into being absent and providing a default for that case (that is still true in the current codebase - I will hopefully fix that eventually). But I now had less room for mistakes and a standardized error message when you misspell the package name, which was a plus.
The added side-effect - Introspection A lovely side-effect of all the parsing logic being provided to debputy in a declarative form was that the generated parser snippets had fields containing all expected attributes with their types, which attributes were required, etc. This meant that adding an introspection feature where you can ask debputy "What does an install rule look like?" was quite easy. The code base already knew all of this, so the "hard" part was resolving the input the to concrete rule and then rendering it to the user. I added this feature recently along with the ability to provide online documentation for parser rules. I covered that in more details in my blog post Providing online reference documentation for debputy in case you are interested. :)
Wrapping it up This was a short insight into how debputy parses your input. With this declarative technique:
  • The parser engine handles most of the error reporting meaning users get most of the errors in a standard format without the plugin provider having to spend any effort on it. There will be some effort in more complex cases. But the common cases are done for you.
  • It is easy to provide flexibility to users while avoiding having to write code to normalize the user input into a simplified programmer oriented format.
  • The parser handles mapping from basic types into higher forms for you. These days, we have high level types like FileSystemMode (either an octal or a symbolic mode), different kind of file system matches depending on whether globs should be performed, etc. These types includes their own validation and parsing rules that debputy handles for you.
  • Introspection and support for providing online reference documentation. Also, debputy checks that the provided attribute documentation covers all the attributes in the manifest form. If you add a new attribute, debputy will remind you if you forget to document it as well. :)
In this way everybody wins. Yes, writing this parser generator code was more enjoyable than writing the ad-hoc manual parsers it replaced. :)

18 January 2024

Russell Coker: LicheePi 4A (RISC-V) First Look

I Just bought a LicheePi 4A RISC-V embedded computer (like a RaspberryPi but with a RISC-V CPU) for $322.68 from Aliexpress (the official site for buying LicheePi devices). Here is the Sipheed web page about it and their other recent offerings [1]. I got the version with 16G of RAM and 128G of storage, I probably don t need that much storage (I can use NFS or USB) but 16G of RAM is good for VMs. Here is the Wiki about this board [2]. Configuration When you get one of these devices you should make setting up ssh server your first priority. I found the HDMI output to be very unreliable. The first monitor I tried was a Samsung 4K monitor dating from when 4K was a new thing, the LicheePi initially refused to operate at a resolution higher than 1024*768 but later on switched to 4K resolution when resuming from screen-blank for no apparent reason (and the window manager didn t support this properly). On the Dell 4K monitor I use on my main workstation it sometimes refused to talk to it and occasionally worked. I got it running at 1920*1080 without problems and then switched it to 4K and it lost video sync and never talked to that monitor again. On my Desklab portabable 4K monitor I got it to display in 4K resolution but only the top left 1/4 of the screen displayed. The issues with HDMI monitor support greatly limit the immediate potential for using this as a workstation. It doesn t make it impossible but would be fiddly at best. It s quite likely that a future OS update will fix this. But at the moment it s best used as a server. The LicheePi has a custom Linux distribution based on Ubuntu so you want too put something like the following in /etc/network/interfaces to make it automatically connect to the ethernet when plugged in:
auto end0
iface end0 inet dhcp
Then to get sshd to start you have to run the following commands to generate ssh host keys that aren t zero bytes long:
rm /etc/ssh/ssh_host_*
systemctl restart ssh.service
It appears to have wifi hardware but the OS doesn t recognise it. This isn t a priority for me as I mostly want to use it as a server. Performance For the first test of performance I created a 100MB file from /dev/urandom and then tried compressing it on various systems. With zstd -9 it took 16.893 user seconds on the LicheePi4A, 0.428s on my Thinkpad X1 Carbon Gen5 with a i5-6300U CPU (Debian/Unstable), 1.288s on my E5-2696 v3 workstation (Debian/Bookworm), 0.467s on the E5-2696 v3 running Debian/Unstable, 2.067s on a E3-1271 v3 server, and 7.179s on the E3-1271 v3 system emulating a RISC-V system via QEMU running Debian/Unstable. It s very impressive that the QEMU emulation is fast enough that emulating a different CPU architecture is only 3.5* slower for this test (or maybe 10* slower if it was running Debian/Unstable on the AMD64 code)! The emulated RISC-V is also more than twice as fast as real RISC-V hardware and probably of comparable speed to real RISC-V hardware when running the same versions (and might be slightly slower if running the same version of zstd) which is a tribute to the quality of emulation. One performance issue that most people don t notice is the time taken to negotiate ssh sessions. It s usually not noticed because the common CPUs have got faster at about the same rate as the algorithms for encryption and authentication have become more complex. On my i5-6300U laptop it takes 0m0.384s to run ssh -i ~/.ssh/id_ed25519 localhost id with the below server settings (taken from advice on ssh-audit.com [3] for a secure ssh configuration). On the E3-1271 v3 server it is 0.336s, on the QMU system it is 28.022s, and on the LicheePi it is 0.592s. By this metric the LicheePi is about 80% slower than decent x86 systems and the QEMU emulation of RISC-V is 73* slower than the x86 system it runs on. Does crypto depend on instructions that are difficult to emulate?
HostKey /etc/ssh/ssh_host_ed25519_key
KexAlgorithms -ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group14-sha256
MACs -umac-64-etm@openssh.com,hmac-sha1-etm@openssh.com,umac-64@openssh.com,umac-128@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-sha1
I haven t yet tested the performance of Ethernet (what routing speed can you get through the 2 gigabit ports?), emmc storage, and USB. At the moment I ve been focused on using RISC-V as a test and development platform. My conclusion is that I m glad I don t plan to compile many kernels or anything large like LibreOffice. But that for typical development that I do it will be quite adequate. The speed of Chromium seems adequate in basic tests, but the video output hasn t worked reliably enough to do advanced tests. Hardware Features Having two Gigabit Ethernet ports, 4 USB-3 ports, and Wifi on board gives some great options for using this as a router. It s disappointing that they didn t go with 2.5Gbit as everyone seems to be doing that nowadays but Gigabit is enough for most things. Having only a single HDMI port and not supporting USB-C docks (the USB-C port appears to be power only) limits what can be done for workstation use and for controlling displays. I know of people using small ARM computers attached to the back of large TVs for advertising purposes and that isn t going to be a great option for this. The CPU and RAM apparently uses a lot of power (which is relative the entire system draws up to 2A at 5V so the CPU would be something below 5W). To get this working a cooling fan has to be stuck to the CPU and RAM chips via a layer of thermal stuff that resembles a fine sheet of blu-tack in both color and stickyness. I am disappointed that there isn t any more solid form of construction, to mount this on a wall or ceiling some extra hardware would be needed to secure this. Also if they just had a really big copper heatsink I think that would be better. 80386 CPUs with similar TDP were able to run without a fan. I wonder how things would work with all USB ports in use. It s expected that a USB port can supply a minimum of 2.5W which means that all the ports could require 10W if they were active. Presumably something significantly less than 5W is available for the USB ports. Other Devices Sipheed has a range of other devices in the works. They currently sell the LicheeCluster4A which support 7 compute modules for a cluster in a box. This has some interesting potential for testing and demonstrating cluster software but you could probably buy an AMD64 system with more compute power for less money. The Lichee Console 4A is a tiny laptop which could be useful for people who like the 7 laptop form factor, unfortunately it only has a 1280*800 display if it had the same resolution display as a typical 7 phone I would have bought one. The next device that appeals to me is the soon to be released Lichee Pad 4A which is a 10.1 tablet with 1920*1200 display, Wifi6, Bluetooth 5.4, and 16G of RAM. It also has 1 USB-C connection, 2*USB-3 sockets, and support for an external card with 2*Gigabit ethernet. It s a tablet as a laptop without keyboard instead of the more common larger phone design model. They are also about to release the LicheePadMax4A which is similar to the other tablet but with a 14 2240*1400 display and which ships with a keyboard to make it essentially a laptop with detachable keyboard. Conclusion At this time I wouldn t recommend that this device be used as a workstation or laptop, although the people who want to do such things will probably do it anyway regardless of my recommendations. I think it will be very useful as a test system for RISC-V development. I have some friends who are interested in this sort of thing and I can give them VMs. It is a bit expensive. The Sipheed web site boasts about the LicheePi4 being faster than the RaspberryPi4, but it s not a lot faster and the RaspberryPi4 is much cheaper ($127 or $129 for one with 8G of RAM). The RaspberryPi4 has two HDMI ports but a limit of 8G of RAM while the LicheePi has up to 16G of RAM and two Gigabit Ethernet ports but only a single HDMI port. It seems that the RaspberryPi4 might win if you want a cheap low power desktop system. At this time I think the reason for this device is testing out RISC-V as an alternative to the AMD64 and ARM64 architectures. An open CPU architecture goes well with free software, but it isn t just people who are into FOSS who are testing such things. I know some corporations are trying out RISC-V as a way of getting other options for embedded systems that don t involve paying monopolists. The Lichee Console 4A is probably a usable tiny laptop if the resolution is sufficient for your needs. As an aside I predict that the tiny laptop or pocket computer segment will take off in the near future. There are some AMD64 systems the size of a phone but thicker that run Windows and go for reasonable prices on AliExpress. Hopefully in the near future this device will have better video drivers and be usable as a small and quiet workstation. I won t rule out the possibility of making this my main workstation in the not too distant future, all it needs is reliable 4K display and the ability to decode 4K video. It s performance for web browsing and as an ssh client seems adequate, and that s what matters for my workstation use. But for the moment it s just for server use.

11 January 2024

Reproducible Builds: Reproducible Builds in December 2023

Welcome to the December 2023 report from the Reproducible Builds project! In these reports we outline the most important things that we have been up to over the past month. As a rather rapid recap, whilst anyone may inspect the source code of free software for malicious flaws, almost all software is distributed to end users as pre-compiled binaries (more).

Reproducible Builds: Increasing the Integrity of Software Supply Chains awarded IEEE Software Best Paper award In February 2022, we announced in these reports that a paper written by Chris Lamb and Stefano Zacchiroli was now available in the March/April 2022 issue of IEEE Software. Titled Reproducible Builds: Increasing the Integrity of Software Supply Chains (PDF). This month, however, IEEE Software announced that this paper has won their Best Paper award for 2022.

Reproducibility to affect package migration policy in Debian In a post summarising the activities of the Debian Release Team at a recent in-person Debian event in Cambridge, UK, Paul Gevers announced a change to the way packages are migrated into the staging area for the next stable Debian release based on its reproducibility status:
The folks from the Reproducibility Project have come a long way since they started working on it 10 years ago, and we believe it s time for the next step in Debian. Several weeks ago, we enabled a migration policy in our migration software that checks for regression in reproducibility. At this moment, that is presented as just for info, but we intend to change that to delays in the not so distant future. We eventually want all packages to be reproducible. To stimulate maintainers to make their packages reproducible now, we ll soon start to apply a bounty [speedup] for reproducible builds, like we ve done with passing autopkgtests for years. We ll reduce the bounty for successful autopkgtests at that moment in time.

Speranza: Usable, privacy-friendly software signing Kelsey Merrill, Karen Sollins, Santiago Torres-Arias and Zachary Newman have developed a new system called Speranza, which is aimed at reassuring software consumers that the product they are getting has not been tampered with and is coming directly from a source they trust. A write-up on TechXplore.com goes into some more details:
What we have done, explains Sollins, is to develop, prove correct, and demonstrate the viability of an approach that allows the [software] maintainers to remain anonymous. Preserving anonymity is obviously important, given that almost everyone software developers included value their confidentiality. This new approach, Sollins adds, simultaneously allows [software] users to have confidence that the maintainers are, in fact, legitimate maintainers and, furthermore, that the code being downloaded is, in fact, the correct code of that maintainer. [ ]
The corresponding paper is published on the arXiv preprint server in various formats, and the announcement has also been covered in MIT News.

Nondeterministic Git bundles Paul Baecher published an interesting blog post on Reproducible git bundles. For those who are not familiar with them, Git bundles are used for the offline transfer of Git objects without an active server sitting on the other side of a network connection. Anyway, Paul wrote about writing a backup system for his entire system, but:
I noticed that a small but fixed subset of [Git] repositories are getting backed up despite having no changes made. That is odd because I would think that repeated bundling of the same repository state should create the exact same bundle. However [it] turns out that for some, repositories bundling is nondeterministic.
Paul goes on to to describe his solution, which involves forcing git to be single threaded makes the output deterministic . The article was also discussed on Hacker News.

Output from libxlst now deterministic libxslt is the XSLT C library developed for the GNOME project, where XSLT itself is an XML language to define transformations for XML files. This month, it was revealed that the result of the generate-id() XSLT function is now deterministic across multiple transformations, fixing many issues with reproducible builds. As the Git commit by Nick Wellnhofer describes:
Rework the generate-id() function to return deterministic values. We use
a simple incrementing counter and store ids in the 'psvi' member of
nodes which was freed up by previous commits. The presence of an id is
indicated by a new "source node" flag.
This fixes long-standing problems with reproducible builds, see
https://bugzilla.gnome.org/show_bug.cgi?id=751621
This also hardens security, as the old implementation leaked the
difference between a heap and a global pointer, see
https://bugs.chromium.org/p/chromium/issues/detail?id=1356211
The old implementation could also generate the same id for dynamically
created nodes which happened to reuse the same memory. Ids for namespace
nodes were completely broken. They now use the id of the parent element
together with the hex-encoded namespace prefix.

Community updates There were made a number of improvements to our website, including Chris Lamb fixing the generate-draft script to not blow up if the input files have been corrupted today or even in the past [ ], Holger Levsen updated the Hamburg 2023 summit to add a link to farewell post [ ] & to add a picture of a Post-It note. [ ], and Pol Dellaiera updated the paragraph about tar and the --clamp-mtime flag [ ]. On our mailing list this month, Bernhard M. Wiedemann posted an interesting summary on some of the reasons why packages are still not reproducible in 2023. diffoscope is our in-depth and content-aware diff utility that can locate and diagnose reproducibility issues. This month, Chris Lamb made a number of changes, including processing objdump symbol comment filter inputs as Python byte (and not str) instances [ ] and Vagrant Cascadian extended diffoscope support for GNU Guix [ ] and updated the version in that distribution to version 253 [ ].

Challenges of Producing Software Bill Of Materials for Java Musard Balliu, Benoit Baudry, Sofia Bobadilla, Mathias Ekstedt, Martin Monperrus, Javier Ron, Aman Sharma, Gabriel Skoglund, C sar Soto-Valero and Martin Wittlinger (!) of the KTH Royal Institute of Technology in Sweden, have published an article in which they:
deep-dive into 6 tools and the accuracy of the SBOMs they produce for complex open-source Java projects. Our novel insights reveal some hard challenges regarding the accurate production and usage of software bills of materials.
The paper is available on arXiv.

Debian Non-Maintainer campaign As mentioned in previous reports, the Reproducible Builds team within Debian has been organising a series of online and offline sprints in order to clear the huge backlog of reproducible builds patches submitted by performing so-called NMUs (Non-Maintainer Uploads). During December, Vagrant Cascadian performed a number of such uploads, including: In addition, Holger Levsen performed three no-source-change NMUs in order to address the last packages without .buildinfo files in Debian trixie, specifically lorene (0.0.0~cvs20161116+dfsg-1.1), maria (1.3.5-4.2) and ruby-rinku (1.7.3-2.1).

Reproducibility testing framework The Reproducible Builds project operates a comprehensive testing framework (available at tests.reproducible-builds.org) in order to check packages and other artifacts for reproducibility. In December, a number of changes were made by Holger Levsen:
  • Debian-related changes:
    • Fix matching packages for the [R programming language](https://en.wikipedia.org/wiki/R_(programming_language). [ ][ ][ ]
    • Add a Certbot configuration for the Nginx web server. [ ]
    • Enable debugging for the create-meta-pkgs tool. [ ][ ]
  • Arch Linux-related changes
    • The asp has been deprecated by pkgctl; thanks to dvzrv for the pointer. [ ]
    • Disable the Arch Linux builders for now. [ ]
    • Stop referring to the /trunk branch / subdirectory. [ ]
    • Use --protocol https when cloning repositories using the pkgctl tool. [ ]
  • Misc changes:
    • Install the python3-setuptools and swig packages, which are now needed to build OpenWrt. [ ]
    • Install pkg-config needed to build Coreboot artifacts. [ ]
    • Detect failures due to an issue where the fakeroot tool is implicitly required but not automatically installed. [ ]
    • Detect failures due to rename of the vmlinuz file. [ ]
    • Improve the grammar of an error message. [ ]
    • Document that freebsd-jenkins.debian.net has been updated to FreeBSD 14.0. [ ]
In addition, node maintenance was performed by Holger Levsen [ ] and Vagrant Cascadian [ ].

Upstream patches The Reproducible Builds project detects, dissects and attempts to fix as many currently-unreproducible packages as possible. We endeavour to send all of our patches upstream where appropriate. This month, we wrote a large number of such patches, including:

If you are interested in contributing to the Reproducible Builds project, please visit our Contribute page on our website. However, you can get in touch with us via:

Matthias Klumpp: Wayland really breaks things Just for now?

This post is in part a response to an aspect of Nate s post Does Wayland really break everything? , but also my reflection on discussing Wayland protocol additions, a unique pleasure that I have been involved with for the past months1.

Some facts Before I start I want to make a few things clear: The Linux desktop will be moving to Wayland2 this is a fact at this point (and has been for a while), sticking to X11 makes no sense for future projects. From reading Wayland protocols and working with it at a much lower level than I ever wanted to, it is also very clear to me that Wayland is an exceptionally well-designed core protocol, and so are the additional extension protocols (xdg-shell & Co.). The modularity of Wayland is great, it gives it incredible flexibility and will for sure turn out to be good for the long-term viability of this project (and also provides a path to correct protocol issues in future, if one is found). In other words: Wayland is an amazing foundation to build on, and a lot of its design decisions make a lot of sense! The shift towards people seeing Linux more as an application developer platform, and taking PipeWire and XDG Portals into account when designing for Wayland is also an amazing development and I love to see this this holistic approach is something I always wanted! Furthermore, I think Wayland removes a lot of functionality that shouldn t exist in a modern compositor and that s a good thing too! Some of X11 s features and design decisions had clear drawbacks that we shouldn t replicate. I highly recommend to read Nate s blog post, it s very good and goes into more detail. And due to all of this, I firmly believe that any advancement in the Wayland space must come from within the project.

But! But! Of course there was a but coming  I think while developing Wayland-as-an-ecosystem we are now entrenched into narrow concepts of how a desktop should work. While discussing Wayland protocol additions, a lot of concepts clash, people from different desktops with different design philosophies debate the merits of those over and over again never reaching any conclusion (just as you will never get an answer out of humans whether sushi or pizza is the clearly superior food, or whether CSD or SSD is better). Some people want to use Wayland as a vehicle to force applications to submit to their desktop s design philosophies, others prefer the smallest and leanest protocol possible, other developers want the most elegant behavior possible. To be clear, I think those are all very valid approaches. But this also creates problems: By switching to Wayland compositors, we are already forcing a lot of porting work onto toolkit developers and application developers. This is annoying, but just work that has to be done. It becomes frustrating though if Wayland provides toolkits with absolutely no way to reach their goal in any reasonable way. For Nate s Photoshop analogy: Of course Linux does not break Photoshop, it is Adobe s responsibility to port it. But what if Linux was missing a crucial syscall that Photoshop needed for proper functionality and Adobe couldn t port it without that? In that case it becomes much less clear on who is to blame for Photoshop not being available. A lot of Wayland protocol work is focused on the environment and design, while applications and work to port them often is considered less. I think this happens because the overlap between application developers and developers of the desktop environments is not necessarily large, and the overlap with people willing to engage with Wayland upstream is even smaller. The combination of Windows developers porting apps to Linux and having involvement with toolkits or Wayland is pretty much nonexistent. So they have less of a voice.

A quick detour through the neuroscience research lab I have been involved with Freedesktop, GNOME and KDE for an incredibly long time now (more than a decade), but my actual job (besides consulting for Purism) is that of a PhD candidate in a neuroscience research lab (working on the morphology of biological neurons and its relation to behavior). I am mostly involved with three research groups in our institute, which is about 35 people. Most of us do all our data analysis on powerful servers which we connect to using RDP (with KDE Plasma as desktop). Since I joined, I have been pushing the envelope a bit to extend Linux usage to data acquisition and regular clients, and to have our data acquisition hardware interface well with it. Linux brings some unique advantages for use in research, besides the obvious one of having every step of your data management platform introspectable with no black boxes left, a goal I value very highly in research (but this would be its own blogpost). In terms of operating system usage though, most systems are still Windows-based. Windows is what companies develop for, and what people use by default and are familiar with. The choice of operating system is very strongly driven by application availability, and WSL being really good makes this somewhat worse, as it removes the need for people to switch to a real Linux system entirely if there is the occasional software requiring it. Yet, we have a lot more Linux users than before, and use it in many places where it makes sense. I also developed a novel data acquisition software that even runs on Linux-only and uses the abilities of the platform to its fullest extent. All of this resulted in me asking existing software and hardware vendors for Linux support a lot more often. Vendor-customer relationship in science is usually pretty good, and vendors do usually want to help out. Same for open source projects, especially if you offer to do Linux porting work for them But overall, the ease of use and availability of required applications and their usability rules supreme. Most people are not technically knowledgeable and just want to get their research done in the best way possible, getting the best results with the least amount of friction.
KDE/Linux usage at a control station for a particle accelerator at Adlershof Technology Park, Germany, for reference (by 25years of KDE)3

Back to the point The point of that story is this: GNOME, KDE, RHEL, Debian or Ubuntu: They all do not matter if the necessary applications are not available for them. And as soon as they are, the easiest-to-use solution wins. There are many facets of easiest : In many cases this is RHEL due to Red Hat support contracts being available, in many other cases it is Ubuntu due to its mindshare and ease of use. KDE Plasma is also frequently seen, as it is perceived a bit easier to onboard Windows users with it (among other benefits). Ultimately, it comes down to applications and 3rd-party support though. Here s a dirty secret: In many cases, porting an application to Linux is not that difficult. The thing that companies (and FLOSS projects too!) struggle with and will calculate the merits of carefully in advance is whether it is worth the support cost as well as continuous QA/testing. Their staff will have to do all of that work, and they could spend that time on other tasks after all. So if they learn that porting to Linux not only means added testing and support, but also means to choose between the legacy X11 display server that allows for 1:1 porting from Windows or the new Wayland compositors that do not support the same features they need, they will quickly consider it not worth the effort at all. I have seen this happen. Of course many apps use a cross-platform toolkit like Qt, which greatly simplifies porting. But this just moves the issue one layer down, as now the toolkit needs to abstract Windows, macOS and Wayland. And Wayland does not contain features to do certain things or does them very differently from e.g. Windows, so toolkits have no way to actually implement the existing functionality in a way that works on all platforms. So in Qt s documentation you will often find texts like works everywhere except for on Wayland compositors or mobile 4. Many missing bits or altered behavior are just papercuts, but those add up. And if users will have a worse experience, this will translate to more support work, or people not wanting to use the software on the respective platform.

What s missing?

Window positioning SDI applications with multiple windows are very popular in the scientific world. For data acquisition (for example with microscopes) we often have one monitor with control elements and one larger one with the recorded image. There is also other configurations where multiple signal modalities are acquired, and the experimenter aligns windows exactly in the way they want and expects the layout to be stored and to be loaded upon reopening the application. Even in the image from Adlershof Technology Park above you can see this style of UI design, at mega-scale. Being able to pop-out elements as windows from a single-window application to move them around freely is another frequently used paradigm, and immensely useful with these complex apps. It is important to note that this is not a legacy design, but in many cases an intentional choice these kinds of apps work incredibly well on larger screens or many screens and are very flexible (you can have any window configuration you want, and switch between them using the (usually) great window management abilities of your desktop). Of course, these apps will work terribly on tablets and small form factors, but that is not the purpose they were designed for and nobody would use them that way. I assumed for sure these features would be implemented at some point, but when it became clear that that would not happen, I created the ext-placement protocol which had some good discussion but was ultimately rejected from the xdg namespace. I then tried another solution based on feedback, which turned out not to work for most apps, and now proposed xdg-placement (v2) in an attempt to maybe still get some protocol done that we can agree on, exploring more options before pushing the existing protocol for inclusion into the ext Wayland protocol namespace. Meanwhile though, we can not port any application that needs this feature, while at the same time we are switching desktops and distributions to Wayland by default.

Window position restoration Similarly, a protocol to save & restore window positions was already proposed in 2018, 6 years ago now, but it has still not been agreed upon, and may not even help multiwindow apps in its current form. The absence of this protocol means that applications can not restore their former window positions, and the user has to move them to their previous place again and again. Meanwhile, toolkits can not adopt these protocols and applications can not use them and can not be ported to Wayland without introducing papercuts.

Window icons Similarly, individual windows can not set their own icons, and not-installed applications can not have an icon at all because there is no desktop-entry file to load the icon from and no icon in the theme for them. You would think this is a niche issue, but for applications that create many windows, providing icons for them so the user can find them is fairly important. Of course it s not the end of the world if every window has the same icon, but it s one of those papercuts that make the software slightly less user-friendly. Even applications with fewer windows like LibrePCB are affected, so much so that they rather run their app through Xwayland for now. I decided to address this after I was working on data analysis of image data in a Python virtualenv, where my code and the Python libraries used created lots of windows all with the default yellow W icon, making it impossible to distinguish them at a glance. This is xdg-toplevel-icon now, but of course it is an uphill battle where the very premise of needing this is questioned. So applications can not use it yet.

Limited window abilities requiring specialized protocols Firefox has a picture-in-picture feature, allowing it to pop out media from a mediaplayer as separate floating window so the user can watch the media while doing other things. On X11 this is easily realized, but on Wayland the restrictions posed on windows necessitate a different solution. The xdg-pip protocol was proposed for this specialized usecase, but it is also not merged yet. So this feature does not work as well on Wayland.

Automated GUI testing / accessibility / automation Automation of GUI tasks is a powerful feature, so is the ability to auto-test GUIs. This is being worked on, with libei and wlheadless-run (and stuff like ydotool exists too), but we re not fully there yet.

Wayland is frustrating for (some) application authors As you see, there is valid applications and valid usecases that can not be ported yet to Wayland with the same feature range they enjoyed on X11, Windows or macOS. So, from an application author s perspective, Wayland does break things quite significantly, because things that worked before can no longer work and Wayland (the whole stack) does not provide any avenue to achieve the same result. Wayland does break screen sharing, global hotkeys, gaming latency (via no tearing ) etc, however for all of these there are solutions available that application authors can port to. And most developers will gladly do that work, especially since the newer APIs are usually a lot better and more robust. But if you give application authors no path forward except use Xwayland and be on emulation as second-class citizen forever , it just results in very frustrated application developers. For some application developers, switching to a Wayland compositor is like buying a canvas from the Linux shop that forces your brush to only draw triangles. But maybe for your avant-garde art, you need to draw a circle. You can approximate one with triangles, but it will never be as good as the artwork of your friends who got their canvases from the Windows or macOS art supply shop and have more freedom to create their art.

Triangles are proven to be the best shape! If you are drawing circles you are creating bad art! Wayland, via its protocol limitations, forces a certain way to build application UX often for the better, but also sometimes to the detriment of users and applications. The protocols are often fairly opinionated, a result of the lessons learned from X11. In any case though, it is the odd one out Windows and macOS do not pose the same limitations (for better or worse!), and the effort to port to Wayland is orders of magnitude bigger, or sometimes in case of the multiwindow UI paradigm impossible to achieve to the same level of polish. Desktop environments of course have a design philosophy that they want to push, and want applications to integrate as much as possible (same as macOS and Windows!). However, there are many applications out there, and pushing a design via protocol limitations will likely just result in fewer apps.

The porting dilemma I spent probably way too much time looking into how to get applications cross-platform and running on Linux, often talking to vendors (FLOSS and proprietary) as well. Wayland limitations aren t the biggest issue by far, but they do start to come come up now, especially in the scientific space with Ubuntu having switched to Wayland by default. For application authors there is often no way to address these issues. Many scientists do not even understand why their Python script that creates some GUIs suddenly behaves weirdly because Qt is now using the Wayland backend on Ubuntu instead of X11. They do not know the difference and also do not want to deal with these details even though they may be programmers as well, the real goal is not to fiddle with the display server, but to get to a scientific result somehow. Another issue is portability layers like Wine which need to run Windows applications as-is on Wayland. Apparently Wine s Wayland driver has some heuristics to make window positioning work (and I am amazed by the work done on this!), but that can only go so far.

A way out? So, how would we actually solve this? Fundamentally, this excessively long blog post boils down to just one essential question: Do we want to force applications to submit to a UX paradigm unconditionally, potentially loosing out on application ports or keeping apps on X11 eternally, or do we want to throw them some rope to get as many applications ported over to Wayland, even through we might sacrifice some protocol purity? I think we really have to answer that to make the discussions on wayland-protocols a lot less grueling. This question can be answered at the wayland-protocols level, but even more so it must be answered by the individual desktops and compositors. If the answer for your environment turns out to be Yes, we want the Wayland protocol to be more opinionated and will not make any compromises for application portability , then your desktop/compositor should just immediately NACK protocols that add something like this and you simply shouldn t engage in the discussion, as you reject the very premise of the new protocol: That it has any merit to exist and is needed in the first place. In this case contributors to Wayland and application authors also know where you stand, and a lot of debate is skipped. Of course, if application authors want to support your environment, you are basically asking them now to rewrite their UI, which they may or may not do. But at least they know what to expect and how to target your environment. If the answer turns out to be We do want some portability , the next question obviously becomes where the line should be drawn and which changes are acceptable and which aren t. We can t blindly copy all X11 behavior, some porting work to Wayland is simply inevitable. Some written rules for that might be nice, but probably more importantly, if you agree fundamentally that there is an issue to be fixed, please engage in the discussions for the respective MRs! We for sure do not want to repeat X11 mistakes, and I am certain that we can implement protocols which provide the required functionality in a way that is a nice compromise in allowing applications a path forward into the Wayland future, while also being as good as possible and improving upon X11. For example, the toplevel-icon proposal is already a lot better than anything X11 ever had. Relaxing ACK requirements for the ext namespace is also a good proposed administrative change, as it allows some compositors to add features they want to support to the shared repository easier, while also not mandating them for others. In my opinion, it would allow for a lot less friction between the two different ideas of how Wayland protocol development should work. Some compositors could move forward and support more protocol extensions, while more restrictive compositors could support less things. Applications can detect supported protocols at launch and change their behavior accordingly (ideally even abstracted by toolkits). You may now say that a lot of apps are ported, so surely this issue can not be that bad. And yes, what Wayland provides today may be enough for 80-90% of all apps. But what I hope the detour into the research lab has done is convince you that this smaller percentage of apps matters. A lot. And that it may be worthwhile to support them. To end on a positive note: When it came to porting concrete apps over to Wayland, the only real showstoppers so far5 were the missing window-positioning and window-position-restore features. I encountered them when porting my own software, and I got the issue as feedback from colleagues and fellow engineers. In second place was UI testing and automation support, the window-icon issue was mentioned twice, but being a cosmetic issue it likely simply hurts people less and they can ignore it easier. What this means is that the majority of apps are already fine, and many others are very, very close! A Wayland future for everyone is within our grasp!  I will also bring my two protocol MRs to their conclusion for sure, because as application developers we need clarity on what the platform (either all desktops or even just a few) supports and will or will not support in future. And the only way to get something good done is by contribution and friendly discussion.

Footnotes
  1. Apologies for the clickbait-y title it comes with the subject
  2. When I talk about Wayland I mean the combined set of display server protocols and accepted protocol extensions, unless otherwise clarified.
  3. I would have picked a picture from our lab, but that would have needed permission first
  4. Qt has awesome platform issues pages, like for macOS and Linux/X11 which help with porting efforts, but Qt doesn t even list Linux/Wayland as supported platform. There is some information though, like window geometry peculiarities, which aren t particularly helpful when porting (but still essential to know).
  5. Besides issues with Nvidia hardware CUDA for simulations and machine-learning is pretty much everywhere, so Nvidia cards are common, which causes trouble on Wayland still. It is improving though.

10 January 2024

Simon Josefsson: Trisquel on arm64: Ampere Altra

Having had success running Trisquel on the ppc64 Talos II, I felt ready to get an arm64 machine running Trisquel. I have a Ampere Altra Developer Platform from ADLINK, which is a fairly powerful desktop machine. While there were some issues during installation, I m happy to say the machine is stable and everything appears to work fine. ISO images for non-amd64 platforms are unfortunately still hidden from the main Trisquel download area, so you will have to use the following procedure to download and extract a netinst ISO image (using debian-installer) and write it to a USB memory device. Another unfortunate problem is that there are no OpenPGP signatures or hash checksums, but below I publish one checksum.
wget -q http://builds.trisquel.org/debian-installer-images/debian-installer-images_20210731+deb11u9+11.0trisquel15_arm64.tar.gz
tar xfa debian-installer-images_20210731+deb11u9+11.0trisquel15_arm64.tar.gz ./installer-arm64/20210731+deb11u9+11/images/netboot/mini.iso
echo '311732519cc8c7c1bb2fe873f134fdafb211ef3bcb5b0d2ecdc6ea4e3b336357  installer-arm64/20210731+deb11u9+11/images/netboot/mini.iso'   sha256sum -c
sudo wipefs -a /dev/sdX
sudo dd if=installer-arm64/20210731+deb11u9+11/images/netboot/mini.iso of=/dev/sdX conv=sync status=progress
Insert the USB stick in a USB slot in the machine, and power up. Press ESCAPE at the BIOS prompt and select the USB device as the boot device. The first problem that hit me was that translations didn t work, I selected Swedish but the strings were garbled. Rebooting and selecting the default English worked fine. For installation, you need Internet connectivity and I use the RJ45 port closest to VGA/serial which is available as enP5p1s0 in the installer. I wouldn t connect the BMC RJ45 port to anything unless you understand the security implications. During installation you have to create a EFI partition for booting, and I ended up with one 1GB EFI partition, one 512GB ext4 partition for / with discard/noatime options, and a 32GB swap partition. The installer did not know about any Trisquel mirrors, but only had the default archive.trisquel.org, so if you need to use a mirror, take a note of the necessary details. The installation asks me about which kernel to install, and I went with the default linux-generic which results in a 5.15 linux-libre kernel. At the end of installation, unfortunately grub failed with a mysterious error message: Unable to install GRUB in dummy. Executing 'grub-install dummy' failed. On another console there is a better error message: failed to register the EFI boot entry. There are some references to file descriptor issues. Perhaps I partitioned the disk in a bad way, or this is a real bug in the installer for this platform. I continued installation, and it appears the installer was able to write GRUB to the device, but not add the right boot menu. So I was able to finish the installation properly, and then reboot and manually type the following GRUB commands: linux (hd0,gpt2)/boot/vmlinuz initrd (hd0,gpt2)/boot/initrd.img boot. Use the GRUB ls command to find the right device. See images below for more information. Booting and installing GRUB again manually works fine:
root@ampel:~# update-grub
Sourcing file  /etc/default/grub'
Sourcing file  /etc/default/grub.d/background.cfg'
Sourcing file  /etc/default/grub.d/init-select.cfg'
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-5.15.0-91-generic
Found initrd image: /boot/initrd.img-5.15.0-91-generic
Found linux image: /boot/vmlinuz-5.15.0-58-generic
Found initrd image: /boot/initrd.img-5.15.0-58-generic
Warning: os-prober will not be executed to detect other bootable partitions.
Systems on them will not be added to the GRUB boot configuration.
Check GRUB_DISABLE_OS_PROBER documentation entry.
Adding boot menu entry for UEFI Firmware Settings ...
done
root@ampel:~# 
During installation I tend to avoid selecting any tasksel components, in part because it didn t use a local mirror to gain network speed, and in part because I don t want to generate OpenSSH keys in a possibly outdated environment that is harder to audit and reproducible rebuild than the finally installed system. When I selected the OpenSSH and GNOME tasksel, I get an error, but fortunately using apt get directly is simple.
root@ampel:~# tasksel
Tasksel GNOME failed:
tasksel: apt-get failed (100)
root@ampel:~# apt-get install trisquel-gnome ssh
Graphics in GNOME was slow using the built-in ASPEED AST2500 VGA controller with linux-libre 5.15. There are kernels labeled 64k but I haven t tested them, and I m not sure they would bring any significant advantage. I simply upgraded to a more recent linux-libre 6.2 kernel via the linux-image-generic-hwe-11.0 virtual package. After a reboot, graphics in GNOME is usable.
root@ampel:~# apt-get install linux-image-generic-hwe-11.0
There seems to be some issue with power-saving inside GNOME, since the machine becomes unresponsive after 20 minutes, and I m unable to make it resume via keyboard or power button. Disabling the inactivity power setting in GNOME works fine to resolve this. I will now put this machine to some more heavy use and see how it handles it. I hope to find more suitable arm64-based servers to complement my ppc64el-based servers in the future, as this ADLINK Ampere Altra Developer Platform with liquid-cooling is more of a toy than a serious server for use in a datacentre. Happy Trisquel-on-arm64 Hacking!

9 January 2024

Louis-Philippe V ronneau: 2023 A Musical Retrospective

I ended 2022 with a musical retrospective and very much enjoyed writing that blog post. As such, I have decided to do the same for 2023! From now on, this will probably be an annual thing :) Albums In 2023, I added 73 new albums to my collection nearly 2 albums every three weeks! I listed them below in the order in which I acquired them. I purchased most of these albums when I could and borrowed the rest at libraries. If you want to browse though, I added links to the album covers pointing either to websites where you can buy them or to Discogs when digital copies weren't available. Once again this year, it seems that Punk (mostly O !) and Metal dominate my list, mostly fueled by Angry Metal Guy and the amazing Montr al Skinhead/Punk concert scene. Concerts A trend I started in 2022 was to go to as many concerts of artists I like as possible. I'm happy to report I went to around 80% more concerts in 2023 than in 2022! Looking back at my list, April was quite a busy month... Here are the concerts I went to in 2023: Although metalfinder continues to work as intended, I'm very glad to have discovered the Montr al underground scene has departed from Facebook/Instagram and adopted en masse Gancio, a FOSS community agenda that supports ActivityPub. Our local instance, askapunk.net is pretty much all I could ask for :) That's it for 2023!

8 January 2024

Russ Allbery: Review: The Faithless

Review: The Faithless, by C.L. Clark
Series: Magic of the Lost #2
Publisher: Orbit
Copyright: March 2023
ISBN: 0-316-54283-0
Format: Kindle
Pages: 527
The Faithless is the second book in a political fantasy series that seems likely to be a trilogy. It is a direct sequel to The Unbroken, which you should read first. As usual, Orbit made it unnecessarily hard to get re-immersed in the world by refusing to provide memory aids for readers who read books as they come out instead of only when the series is complete, but this is not the fault of Clark or the book and you've heard me rant about this before. The Unbroken was set in Qaz l (not-Algeria). The Faithless, as readers of the first book might guess from the title, is set in Balladaire (not-France). This is the palace intrigue book. Princess Luca is fighting for her throne against her uncle, the regent. Touraine is trying to represent her people. Whether and to what extent those interests are aligned is much of the meat of this book. Normally I enjoy palace intrigue novels for the competence porn: watching someone navigate a complex political situation with skill and cunning, or upend the entire system by building unlikely coalitions or using unexpected routes to power. If you are similar, be warned that this is not what you're going to get. Touraine is a fish out of water with no idea how to navigate the Balladairan court, and does not magically become an expert in the course of this novel. Luca has the knowledge, but she's unsure, conflicted, and largely out-maneuvered. That means you will have to brace for some painful scenes of some of the worst people apparently getting what they want. Despite that, I could not put this down. It was infuriating, frustrating, and a much slower burn than I prefer, but the layers of complex motivations that Clark builds up provided a different sort of payoff. Two books in, the shape of this series is becoming clearer. This series is about empire and colonialism, but with considerably more complexity than fantasy normally brings to that topic. Power does not loosen its grasp easily, and it has numerous tools for subtle punishment after apparent upstart victories. Righteous causes rarely call banners to your side; instead, they create opportunities for other people to maneuver to their own advantage. Touraine has some amount of power now, but it's far from obvious how to use it. Her life's training tells her that exercising power will only cause trouble, and her enemies are more than happy to reinforce that message at every opportunity. Most notable to me is Clark's bitingly honest portrayal of the supposed allies within the colonial power. It is clear that Luca is attempting to take the most ethical actions as she defines them, but it's remarkable how those efforts inevitably imply that Touraine should help Luca now in exchange for Luca's tenuous and less-defined possible future aid. This is not even a lie; it may be an accurate summary of Balladairan politics. And yet, somehow what Balladaire needs always matters more than the needs of their abused colony. Underscoring this, Clark introduces another faction in the form of a populist movement against the Balladairan monarchy. The details of that setup in another fantasy novel would make them allies of the Qaz l. Here, as is so often the case in real life, a substantial portion of the populists are even more xenophobic and racist than the nobility. There are no easy alliances. The trump card that Qaz l holds is magic. They have it, and (for reasons explored in The Unbroken) Balladaire needs it, although that is a position held by Luca's faction and not by her uncle. But even Luca wants to reduce that magic to a manageable technology, like any other element of the Balladairan state. She wants to understand it, harness it, and bring it under local control. Touraine, trained by Balladaire and facing Balladairan political problems, has the same tendency. The magic, at least in this book, refuses not in the flashy, rebellious way that it would in most fantasy, but in a frustrating and incomprehensible lack of predictable or convenient rules. I think this will feel like a plot device to some readers, and that is to some extent true, but I think I see glimmers of Clark setting up a conflict of world views that will play out in the third book. I think some people are going to bounce off this book. It's frustrating, enraging, at times melodramatic, and does not offer the cathartic payoff typically offered in fantasy novels of this type. Usually these are things I would be complaining about as well. And yet, I found it satisfyingly challenging, engrossing, and memorable. I spent a lot of the book yelling "just kill him already" at the characters, but I think one of Clark's points is that overcoming colonial relationships requires a lot more than just killing one evil man. The characters profoundly fail to execute some clever and victorious strategy. Instead, as in the first book, they muddle through, making the best choice that they can see in each moment, making lots of mistakes, and paying heavy prices. It's realistic in a way that has nothing to do with blood or violence or grittiness. (Although I did appreciate having the thin thread of Pruett's story and its highly satisfying conclusion.) This is also a slow-burn romance, and there too I think opinions will differ. Touraine and Luca keep circling back to the same arguments and the same frustrations, and there were times that this felt repetitive. It also adds a lot of personal drama to the politics in a way that occasionally made me dubious. But here too, I think Clark is partly using the romance to illustrate the deeper political points. Luca is often insufferable, cruel and ambitious in ways she doesn't realize, and only vaguely able to understand the Qaz l perspective; in short, she's the pragmatic centrist reformer. I am dubious that her ethics would lead her to anything other than endless compromise without Touraine to push her. To Luca's credit, she also realizes that and wants to be a better person, but struggles to have the courage to act on it. Touraine both does and does not want to manipulate her; she wants Luca's help (and more), but it's not clear Luca will give it under acceptable terms, or even understand how much she's demanding. It's that foundational conflict that turns the romance into a slow burn by pushing them apart. Apparently I have more patience for this type of on-again, off-again relationship than one based on artificial miscommunication. The more I noticed the political subtext, the more engaging I found the romance on the surface. I picked this up because I'd read several books about black characters written by white authors, and while there was nothing that wrong with those books, the politics felt a little too reductionist and simplified. I wanted a book that was going to force me out of comfortable political assumptions. The Faithless did exactly what I was looking for, and I am definitely here for the rest of the series. In that sense, recommended, although do not go into this book hoping for adroit court maneuvering and competence porn. Followed by The Sovereign, which does not yet have a release date. Content warnings: Child death, attempted cultural genocide. Rating: 7 out of 10

3 January 2024

Jacob Adams: Fixing My Shell

For an embarassingly long time, my shell has unnecessarily tried to initialize a console font in every kind of interactive terminal. This leaves the following error message in my terminal:
Couldn't get a file descriptor referring to the console.
It even shows up twice when running tmux! Clearly I ve done something horrible to my configuration, and now I ve got to clean it up.

How does Shell Initialization Work? The precise files a shell reads at start-up is somewhat complex, and defined by this excellent chart 1: Shell Startup Flowchart For the purposes of what I m trying to fix, there are two paths that matter.
  • Interactive login shell startup
  • Interactive non-login shell startup
As you can see from the above, trying to distinguish these two paths in bash is an absolute mess. zsh, in contrast, is much cleaner and allows for a clear distinction between these two cases, with login shell configuration files as a superset of configuration files used by non-login shells.

How did we get here? I keep my configuration files in a config repository. Some time ago I got quite frustrated at this whole shell initialization thing, and just linked everything together in one profile file:
.mkshrc -> config/profile
.profile -> config/profile
This appears to have created this mess.

Move to ZSH I ve wanted to move to zsh for a while, and took this opportunity to do so. So my new configuration files are .zprofile and .zshrc instead of .mkshrc and .profile (though I m going to retain those symlinks to allow my old configurations to continue working). mksh is a nice simple shell, but using zsh here allows for more consistency between my home and $WORK environments, and will allow a lot more powerful extensions.

Updating my Prompt ZSH prompts use a totally different configuration via variable expansion. However, it also uses the PROMPT variable, so I set that to the needed values for zsh. There s an excellent ZSH prompt generator at https://zsh-prompt-generator.site that I used to get these variables, though I m sure they re in the zsh documentation somewhere as well. I wanted a simple prompt with user (%n), host (%m), and path (%d). I also wanted a % at the end to distinguish this from other shells.
PROMPT="%n@%m%d%% "

Fixing mksh prompts This worked but surprisingly mksh also looks at PROMPT, leaving my mksh prompt as the literal prompt string without expansion. Fixing this requires setting up a proper shrc and linking it to .mkshrc and .zshrc. I chose to move my existing aliases script to this file, as it also broke in non-login shells when moved to profile. Within this new shrc file we can check what shell we re running via $0:
if [ "$0" = "/bin/zsh" ]   [ "$0" = "zsh" ]   [ "$0" = "-zsh" ]
I chose to add plain zsh here in case I run it manually for whatever reason. I also added -zsh to support tmux as that s what it presents as $0. This also means you ll need to be careful to quote $0 or you ll get fun shell errors. There s probably a better way to do this, but I couldn t find something that was compatible with POSIX shell, which is what most of this has to be written in to be compatible with mksh and zsh2. We can then setup different prompts for each:
if [ "$0" = "/bin/zsh" ]   [ "$0" = "zsh" ]   [ "$0" = "-zsh" ]
then
	PROMPT="%n@%m%d%% "
else
	# Borrowed from
	# http://www.unixmantra.com/2013/05/setting-custom-prompt-in-ksh.html
	PS1='$(id -un)@$(hostname -s)$PWD$ '
fi

Setting Console Font in a Better Way I ve been setting console font via setfont in my .profile for a while. I m not sure where I picked this up, but it s not the right way. I even tried to only run this in a console with -t but that only checks that output is a terminal, not specifically a console.
if [ -t 1 ]
then
	setfont /usr/share/consolefonts/Lat15-Terminus20x10.psf.gz
fi
This also only runs once the console is logged into, instead of initializing it on boot. The correct way to set this up, on Debian-based systems, is reconfiguring console-setup like so:
dpkg-reconfigure console-setup
From there you get a menu of encoding, character set, font, and then font size to configure for your consoles.

VIM mode To enable VIM mode for ZSH, you simply need to set:
bindkeys -v
This allows you to edit your shell commands with basic VIM keybinds.

Getting back Ctrl + Left Arrow and Ctrl + Right Arrow Moving around one word at a time with Ctrl and the arrow keys is broken by vim mode unfortunately, so we ll need to re-enable it:
bindkey "^[[1;5C" forward-word
bindkey "^[[1;5D" backward-word

Why did it show up twice for tmux? Because tmux creates a login shell. Adding:
echo PROFILE
to profile and:
echo SHRC
to shrc confirms this with:
PROFILE
SHRC
SHRC
For now, profile sources shrc so that running twice is expected. But after this exploration and diagram, it s clear we don t need that for zsh. Removing this will break remote bash shells (see above diagram), but I can live without those on my development laptop. Removing that line results in the expected output for a new terminal:
SHRC
And the full output for a new tmux session or console:
PROFILE
SHRC
So finally we re back to a normal state! This post is a bit unfocused but I hope it helps someone else repair or enhance their shell environment. If you liked this4, or know of any other ways to manage this I could use, let me know at fixmyshell@tookmund.com.
  1. This chart comes from the excellent Shell Startup Scripts article by Peter Ward. I ve generated the SVG from the graphviz source linked in the article.
  2. Technically it has be compatible with Korn shell, but a quick google seems to suggest that that s actually a subset of POSIX shell.
  3. I use oh-my-zsh at $WORK but for now I m going to simplify my personal configuration. If I end up using a lot of plugins I ll reconsider this.
  4. Or if you ve found any typos or other issues that I should fix.

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