In Debian stretch, the upcoming new release, it is now possible to build Android apps using only packages from Debian. This will provide all of the tools needed to build an Android app targeting the "platform" android-23 using the SDK build-tools 24.0.0. Those two are the only versions of "platform" and "build-tools" currently in Debian, but it is possible to use the Google binaries by installing them into /usr/lib/android-sdk. This doesn't cover yet all of the libraries that are used in the app, like the Android Support libraries, or all of the other myriad libraries that are usually fetched from jCenter or Maven Central. One big question for us is whether and how libraries should be included in Debian. All the Java libraries in Debian can be used in an Android app, but including something like Android Support in Debian would be strange since they are only useful in an Android app, never for a Debian app. Building apps with these packages Here are the steps for building Android apps using Debian's Android SDK on Stretch.

1. sudo apt install android-sdk android-sdk-platform-23
2. export ANDROID_HOME=/usr/lib/android-sdk
3. In build.gradle, set compileSdkVersion to 23 and buildToolsVersion to 24.0.0
4. run gradle build

The Gradle Android Plugin is also packaged. Using the Debian package instead of the one from online Maven repositories requires a little configuration before running gradle. In the buildscript block:

• add maven url 'file:///usr/share/maven-repo' to repositories
• use compile 'com.android.tools.build:gradle:debian' to load the plugin

Currently there is only the target platform of API Level 23 packaged, so only apps targeted at android-23 can be built with only Debian packages. There are plans to add more API platform packages via backports. Only build-tools 24.0.0 is available, so in order to use the SDK, build scripts need to be modified. Beware that the Lint in this version of Gradle Android Plugin is still problematic, so running the :lint tasks might not work. They can be turned off with lintOptions.abortOnError in build.gradle. Google binaries can be combined with the Debian packages, for example to use a different version of the platform or build-tools. Why include the Android SDK in Debian? While Android developers could develop and ship apps right now using these Debian packages, this is not very flexible since only build-tools-24.0.0 and android-23 platform are available. Currently, the Debian Android Tools Team is not aiming to cover the most common use cases. Those are pretty well covered by Google's binaries (except for the proprietary license on the Google binaries), and are probably the most work for the Android Tools Team to cover. The current focus is on use cases that are poorly covered by the Google binaries, for example, like where only specific parts of the whole SDK are used. Here are some examples:

• tools for security researchers, forensics, reverse engineering, etc. which can then be included in live CDs and distros like Kali Linux
• a hardened APK signing server using apksigner that uses a standard, audited, public configuration of all reproducibly built packages
• Replicant is a 100% free software Android distribution, so of course they want to have a 100% free software SDK
• high security apps need a build environment that matches their level of security, the Debian Android Tools packages are reproducibly built only from publicly available sources
• support architectures besides i386 and amd64, for example, the Linaro LAVA setup for testing ARM devices of all kinds uses the adb packages on ARM servers to make their whole testing setup all ARM architecture
• dead simple install with strong trust path with mirrors all over the world

In the long run, the Android Tools Team aims to cover more use cases well, and also building the Android NDK. This all will happen more quickly if there are more contributors on the Android Tools team! Android is the most popular mobile OS, and can be 100% free software like Debian. Debian and its derivatives are one of the most popular platforms for Android development. This is an important combination that should grow only more integrated. Last but not least, the Android Tools Team wants feedback on how this should all work, for example, ideas for how to nicely integrate Debian's Java libraries into the Android gradle workflow. And ideally, the Android Support libraries would also be reproducibly built and packaged somewhere that enforces only free software. Come find us on IRC and/or email! https://wiki.debian.org/AndroidTools#Communication_Channels

Consulting for Valve in my spare time Valve Software has asked me to help work on a couple of Linux graphics issues, so I'll be doing a bit of consulting for them in my spare time. It should be an interesting diversion from my day job working for Hewlett Packard Enterprise on Memory Driven Computing and other fun things. First thing on my plate is helping support head-mounted displays better by getting the window system out of the way. I spent some time talking with Dave Airlie and Eric Anholt about how this might work and have started on the kernel side of that. A brief synopsis is that we'll split off some of the output resources from the window system and hand them to the HMD compositor to perform mode setting and page flips. After that, I'll be working out how to improve frame timing reporting back to games from a composited desktop under X. Right now, a game running on X with a compositing manager can't tell when each frame was shown, nor accurately predict when a new frame will be shown. This makes smooth animation rather difficult.

There has been a lot of noise lately about the GOP health care plan (AHCA) and the differences to the current plan (ACA or Obamacare). A lot of statistics are being misinterpreted. The New York Times has an excellent analysis of some of this. But to pick it apart, I want to highlight a few things: Many Republicans are touting the CBO s estimate that, some years out, premiums will be 10% lower under their plan than under the ACA. However, this carries with it a lot of misleading information. First of all, many are spinning this as if costs would go down. That s not the case. The premiums would still rise they would just have risen less by the end of the period than under ACA. That also ignores the immediate spike and throwing millions out of the insurance marketplace altogether. Now then, where does this 10% number come from? First of all, you have to understand the older people are substantially more expensive to the health system, and therefore more expensive to insure. ACA limited the price differential from the youngest to the oldest people, which meant that in effect some young people were subsidizing older ones on the individual market. The GOP plan removes that limit. Combined with other changes in subsidies and tax credits, this dramatically increases the cost to older people. For instance, the New York Times article cites a CBO estimate that the price an average 64-year-old earning $26,500 would need to pay after using a subsidy would increase from $1,700 under Obamacare to $14,600 under the Republican plan. They further conclude that these exceptionally high rates would be so unaffordable to older people that the older people will simply stop buying insurance on the individual market. This means that the overall risk pool of people in that market is healthier, and therefore the average price is lower. So, to sum up: the reason that insurance premiums under the GOP plan will rise at a slightly slower rate long-term is that the higher-risk people will be unable to afford insurance in the first place, leaving only the cheaper people to buy in.

Here's what happened in the Reproducible Builds effort between Sunday March 5 and Saturday March 11 2017: Upcoming events

• On March 23rd Holger Levsen will give a talk at the German Unix User Group's "Fr hjahrsfachgespr ch" called Reproducible Builds everywhere.
• Verifying Software Freedom with Reproducible Builds will be presented by Vagrant Cascadian at Libreplanet2017 in Boston, March 25th.
• You, too, can write reproducible software! workshop by Ximin Luo, Vagrant Cascadian and Valerie Young at Libreplanet2017 in Boston, March 25th.

Reproducible Builds Hackathon Hamburg The Reproducible Builds Hamburg Hackathon 2017, or RB-HH-2017 for short, is a 3 day hacking event taking place in the CCC Hamburg Hackerspace located inside the Frappant, which is collective art space located in a historical monument in Hamburg, Germany. The aim of the hackathon is to spent some days working on Reproducible Builds in every distribution and project. The event is open to anybody interested on working on Reproducible Builds issues in any distro or project, with or without prio experience! Packages filed Chris Lamb:

• #856834 filed against tendermint-go-rpc.
• #856860 filed against archvsync.
• #857122 filed against python-gdata (sent upstream)
• #857313 filed against cylc.
• #857454 filed against qtltools.

Toolchain development

• Guillem Jover uploaded dpkg 1.18.23 to unstable, declaring .buildinfo format 1.0 as "stable".
• Jams McCoy uploaded devscripts 2.17.2 to unstable addingd support for .buildinfo files to the debsign utility via patches from Ximin Luo and Guillem Jover.
• Hans-Christoph Steiner noted that the first reproducibility-related patch in the Android SDK was marked as confirmed.

Reviews of unreproducible packages 39 package reviews have been added, 7 have been updated and 9 have been removed in this week, adding to our knowledge about identified issues. 2 issue types have been added:

• randomness_in_binaries_generated_by_ruby_mkmf
• build_dir_in_documentation_generated_by_doxygen

Weekly QA work During our reproducibility testing, FTBFS bugs have been detected and reported by:

• Chris Lamb (2)

buildinfo.debian.net development

• Chris Lamb:
  • Show reproducible status of package.
  • Inject operator.getitem as a template filter.
  • Include version in BuildInfo's __unicode__

reproducible-website development

• Holger Levsen:
  • Add first batch of post-it notes as pics
  • Add FAQ feedback pad
  • Update report to latest version from Beatrice
  • Polish diffoscope pad
  • Add (unverified) Berlin summit pads from riseup, without interlinks yet

tests.reproducible-builds.org

• Hans-Christoph Steiner gave a progress report on testing F-Droid: we now have a complete vagrant workflow working in nested KVM! So we can provision a new KVM guest, then package it using vagrant box all inside of a KVM guest (which is a profitbricks build node). So we finally have a working setup on jenkins.debian.net. Next up is fixing bugs in our libvirt snapshoting support.
• Then Hans-Christoph was also able to enable building of all F-Droid apps in our setup, though this is still work in progress
• Daniel Shahaf spotted a subtile error in our FreeBSD sudoers configuration and as a result the FreeBSD reproducibility results are back.
• Holger once again adjusted the Debian armhf scheduling frequency, to cope with the ever increasing amount of armhf builds.
• Mattia spotted a refactoring error which resulted in no maintenance mails for a week.
• Holger also spent some time on improving IRC notifications further, though there is still some improvements to be made.

Misc. This week's edition was written by Chris Lamb, Holger Levsen, Vagrant Cascadian & reviewed by a bunch of Reproducible Builds folks on IRC & the mailing lists.

I ve been playing in a 5e campaign for around two months now. In the past ten days or so I ve been reading various source books and Internet threads regarding the design of 5th edition. I d like to draw some comparisons and contrasts between 5th edition, and the 3rd edition family of games (DnD 3.5e and Paizo s Pathfinder, which may be thought of as 3.75e). The first thing I d like to discuss is that wizards and clerics are no longer Vancian spellcasters. In rules terms, this is the idea that individual spells are pieces of ammunition. Spellcasters have a list of individual spells stored in their heads, and as they cast spells from that list, they cross off each item. Barring special rules about spontaneously converting prepared spells to healing spells, for clerics, the only way to add items back to the list is to take a night s rest. Contrast this with spending points from a pool of energy in order to use an ability to cast a fireball. Then the limiting factor on using spells is having enough points in your mana pool, not having further castings of the spell waiting in memory. One of the design goals of 5th edition was to reduce the dominance of spellcasters at higher levels of play. The article to which I linked in the previous paragraph argues that this rebalancing requires the removal of Vancian magic. The idea, to the extent that I ve understood it, is that Vancian magic is not an effective restriction on spellcaster power levels, so it is to be replaced with other restrictions adding new restrictions while retaining the restrictions inherent in Vancian magic would leave spellcasters crippled. A further reason for removing Vancian magic was to defeat the so-called five minute adventuring day . The compat ability of a party that contains higher level Vancian spellcasters drops significantly once they ve fired off their most powerful combat spells. So adventuring groups would find themselves getting into a fight, and then immediately retreating to fully rest up in order to get their spells back. This removes interesting strategic and roleplaying possibilities involving the careful allocation of resources, and continuing to fight as hit points run low. There are some other related changes. Spell components are no longer used up when casting a spell. So you can use one piece of bat guano for every fireball your character ever casts, instead of each casting requiring a new piece. Correspondingly, you can use a spell focus, such as a cool wand, instead of a pouch full of material components since the pouch never runs out, there s no mechanical change if a wizard uses an arcane focus instead. 0th level spells may now be cast at will (although Pathfinder had this too). And there are decent 0th level attack spells, so a spellcaster need not carry a crossbow or shortbow in order to have something to do on rounds when it would not be optimal to fire off one of their precious spells. I am very much in favour of these design goals. The five minute adventuring day gets old fast, and I want it to be possible for the party to rely on the cool abilities of non-spellcasters to deal with the challenges they face. However, I am concerned about the flavour changes that result from the removal of Vancian magic. These affect wizards and clerics differently, so I ll take each case in turn. Firstly, consider wizards. In third edition, a wizard had to prepare and cast Read Magic (the only spell they could prepare without a spellbook), and then set about working through their spellbook. This involved casting the spells they wanted to prepare, up until the last few triggering words or gestures that would cause the effect of the spell to manifest. They would commit these final parts of the spell to memory. When it came to casting the spell, the wizard would say the final few words and make the required gestures, and bring out relevant material components from their component pouch. The completed spell would be ripped out of their mind, to manifest its effect in the world. We see that the casting of a spell is a highly mentally-draining activity it rips the spell out of the caster s memory! not to be undertaken lightly. Thus it is natural that a wizard would learn to use a crossbow for basic damage-dealing. Magic is not something that comes very naturally to the wizard, to be deployed in combat as readily as the fighter swings their sword. They are not a superhero or video game character, pew pew ing their way to victory. This is a very cool starting point upon which to roleplay an academic spellcaster, not really available outside of tabletop games. I see it as a distinction between magical abilities and real magic. Secondly, consider clerics. Most of the remarks in the previous paragraph apply, suitably reworked to be in terms of requesting certain abilities from the deity to whom the cleric is devoted. Additionally, there is the downgrading of the importance of the cleric s healing magic in 5th edition. Characters can heal themselves by taking short and long rests. Previously, natural healing was very slow, so a cleric would need to convert all their remaining magic to healing spells at the end of the day, and hope that it was enough to bring the party up to fighting shape. Again, this made the party of adventurers seem less like superheroes or video game characters. Magic had a special, important and unique role, that couldn t be replaced by the abilities of other classes. I would like to find ways to restore the feel and flavour of Vancian clerics and wizards to 5th edition, without sacrificing the improvements that have been made that let other party members do cool stuff too. I hope it is possible to keep magic cool and unique without making it dominate the game. It would be easy to forbid the use of arcane foci, and say that material component pouches run out if the party do not visit a suitable marketplace often enough. This would not have a significant mechanical effect, and could enhance roleplaying possibilities. I am not sure how I could deal with the other issues I ve discussed without breaking the game. The second thing I would like to discuss is bounded accuracy. Under this design principle, the modifiers to dice rolls grow much more slowly. The gain of hit points remains unbounded. Under third edition, it was mechanically impossible for a low-level monster to land a hit on a higher-level adventurer, rendering them totally useless even in overwhelming numbers. With bounded accuracy, it s always possible for a low-level monster to hit a PC, even if they do insigificant damage. That means that multiple low-level monsters pose a threat. This change opens up many roleplaying opportunities by keeping low-level character abilities relevant, as well as monster types that can remain involves in stories without giving them implausible new abilities so they don t fall far behind the PCs. However, I m a little worried that it might make high level player characters feel a lot less powerful to play. I want to cease a be a fragile adventurer and become a world-changing hero at later levels, rather than forever remain vulnerable to the things that I was vulnerable to at the start of the game. This desire might just be the result of the video games which I played growing up. In the JRPGs I played and in Diablo II, enemies in earlier areas of the map were no threat at all once you d levelled up by conquering higher-level areas. My concerns about bounded accuracy might just be that it clashes with my own expectations of how fantasy heroes work. A good DM might be able to avoid these worries entirely. The final thing I d like to discuss is the various simplifications to the rules of 5th edition, when it is compared with 3rd edition and Pathfinder. Attacks of opportunity are only provoked when leaving a threatened square; you can go ahead and cast a spell when in melee with someone. There is a very short list of skills, and party members are much closer to each other in skills, now that you can t pump more and more ranks into one or two abilities. Feats as a whole are an optional rule. At first I was worried about these simplifications. I thought that they might make character building and tactics in combat a lot less fun. However, I am now broadly in favour of all of these changes, for two reasons. Firstly, they make the game so much more accessible, and make it far more viable to play without relying on a computer program to fill in the boxes on your character sheet. In my 5th edition group, two of us have played 3rd edition games, and the other four have never played any tabletop games before. But nobody has any problems figuring out their modifiers because it is always simply your ability bonus or penalty, plus your proficiency bonus if relevant. And advantage and disadvantage is so much more fun than getting an additional plus or minus two. Secondly, these simplifications downplay the importance of the maths, which means it is far less likely to be broken. It is easier to ensure that a smaller core of rules is balanced than it is to keep in check a larger mass of rules, constantly being supplemented by more and more addon books containing more and more feats and prestige classes. That means that players make their characters cool by roleplaying them in interesting ways, not making them cool by coming up with ability combos and synergies in advance of actually sitting down to play. Similarly, DMs can focus on flavouring monsters, rather than writing up longer stat blocks. I think that this last point reflects what I find most worthwhile about tabletop RPGs. I like characters to encounter cool NPCs and cool situations, and then react in cool ways. I don t care that much about character creation. (I used to care more about this, but I think it was mainly because of interesting options for magic items, which hasn t gone away.) The most important thing is exercising group creativity while actually playing the game, rather than players and DMs having to spend a lot of time preparing the maths in advance of playing. Fifth edition enables this by preventing the rules from getting in the way, because they re broken or overly complex. I think this is why I love Exalted: stunting is vital, and there is social combat. I hope to be able to work out a way to restore Vancian magic, but even without that, on balance, fifth edition seems like a better way to do group storytelling about fantasy heroes. Hopefully I will have an opportunity to DM a 5th edition campaign. I am considering disallowing all homebrew and classes and races from supplemental books. Stick to the well-balanced core rules, and do everything else by means of roleplaying and flavour. This is far less gimmicky, if more work for unimaginative players (such as myself!). Some further interesting reading:

• Rules versus rulings over the five editions
• Threat creation using bounded accuracy
• Pathfinder vs. 5e on reddit
• Pathfinder vs. 5e on StackExchange this claims that 5e is like 2e in being low fantasy, with constant character deaths and thus little longterm character development, but this has not been my experience so far
• On the Defining Characteristic of 5th Edition

Weblate is growing quite well in last months, but sometimes it's development is really driven by people who complain instead of following some roadmap with higher goals. I think it's time to change it at least a little bit. In order to get broader feedback I've sent out short survey to active project owners in Hosted Weblate week ago. I've decided to target at smaller audience for now, though publicly open survey might follow later (but it's always harder to evaluate feedback across different user groups). Overall feelings were really positive, most people find Weblate better than other similar services they have used. This is really something I like to hear :-). But the most important part for me was where users want to see improvements. This somehow matches my expectation that we really should improve the user interface. We have quite a lot features, which are really hidden in the user interface. Also interface for some of the features is far from being intuitive. This all probably comes from the fact that we really don't have anybody experienced with creating user interfaces right now. It's time to find somebody who will help us. In case you are able to help or know somebody who might be interested in helping, please get in touch. Weblate is free software, but this can still be paid job. Last part of the survey was focused on some particular features, but the outcome was not as clear as I hoped for as almost all feature group attracted about same attention (with one exception being extending the API, which was not really wanted by most of the users). Overall I think doing some survey like this is useful and I will certainly repeat it (probably yearly or so), to see where we're moving and what our users want. Having feedback from users is important for every project and this seemed to worked quite well. Anyway if you have further feedback, don't hesitate to use our issue tracker at GitHub or contact me directly.

Filed under: Debian English phpMyAdmin SUSE Weblate 0 comments

It is said that with age comes wisdom. I would be happy for that to be true, because today I must have been very very young then. For example, if you want to make a long bike ride in order to hit some milestone, like your first metric century, it is not indicated to follow ANY of the following points:

• instead of doing this in the season, when you're fit, wait over the winter, during which you should indulge in food and drink with only an occasional short bike ride, so that most of your fitness is gone and replaced by a few extra kilograms;
• instead of choosing a flat route that you've done before, extending it a bit to hit the target distance, think about taking the route from one of the people you follow on Strava (and I mean real cyclists here); bonus points if you choose one they mention was about training instead of a freeride and gave it a meaningful name like "The ride of 3 peaks", something with 1'500m+ altitude gain
• in order to not get bogged down by too much by extra weight (those winter kilograms are enough!), skimp on breakfast (just a very very light one); together with the energy bar you eat, something like 400 calories
• take the same amount of food you take for much shorter and flatter rides; bonus points if you don't check the actual calories in the food, and instead of the presumed 700+ calories you think you're carrying (which might be enough, if you space them correctly, given how much you can absorb per hour), take at most 300 calories with you, because hey, your body is definitely used with long efforts in which you convert fat to energy on the fly, right? especially after said winter pause!
• since water is scarce in the Swiss outdoors (not!), especially when doing a road bike ride, carry lots of water with you (full hydro-pack, 3l) instead of an extra banana or energy bar, or a sandwich, or nuts, or a steak mmmm, steak!
• and finally and most importantly don't do the ride indoors on the trainer, even though it can pretty realistically simulate the effort, but instead do it for real outside, where you can't simply stop when you had enough, because you have to get back home

For bonus points, if you somehow manage to reach the third peak in the above ride, and have mostly only flat/down to the destination, do the following: be so glad you're done with climbing, that you don't pay attention to the map and start a wrong descent, on a busy narrow road, so that you can't stop immediately as you realise you've lost the track; it will cost you only an extra ~80 meters of height towards the end of the ride. Which are pretty cheap, since all the food is gone and the water almost as well, so the backpack is light. Right. However, if you do follow all the above, you're rewarded with a most wonderful thing for the second half of the ride: your will receive a +5 boost on your concentration skill. You will be able to focus on, and think about a single thing for hours at a time, examining it (well, its contents) in minute detail. Plus, when you get home and open that thing I mean, of course, the FRIDGE with all the wonderful FOOD it contains everything will taste MAGICAL! You can now recoup the roughly 1500 calories deficit on the ride, and finally no longer feel SO HUNGRY. That's all. Strava said "EXTREME" suffer score, albeit less than 20% points in the red, which means I was just slugging through the ride (total time confirms it), like a very very very old man. But definitely not a wise one.

Cloning mozilla-central with git-cinnabar requires a lot of memory. Actually too much memory to fit in a 32-bits address space. I hadn t optimized for memory use in the first place. For instance, git-cinnabar keeps sha-1s in memory as hex values (40 bytes) rather than raw values (20 bytes). When I wrote the initial prototype, it didn t matter that much, and while close(ish) to the tipping point, it didn t require more than 2GB of memory at the time. Time passed, and mozilla-central grew. I suspect the recent addition of several thousands of commits and files has made things worse. In order to come up with a plan to make things better (short or longer term), I needed data. So I added some basic memory resource tracking, and collected data while cloning mozilla-central. I must admit, I was not ready for what I witnessed. Follow me for a tale of frustrations (plural). I was expecting things to have gotten worse on the master branch (which I used for the data collection) because I am in the middle of some refactoring and did many changes that I was suspecting might have affected memory usage. I wasn t, however, expecting to see the clone command using 10GB(!) memory at peak usage across all processes. (Note, those memory sizes are RSS, minus shared ) It also was taking an unexpected long time, but then, I hadn t cloned a large repository like mozilla-central from scratch in a while, so I wasn t sure if it was just related to its recent growth in size or otherwise. So I collected data on 0.4.0 as well. Less time spent, less memory usage ok. There s definitely something wrong on master. But wait a minute, that slope from ~2GB to ~4GB on the git-remote-hg process doesn t actually make any kind of sense. I mean, I d understand it if it were starting and finishing with the Import manifest phase, but it starts in the middle of it, and ends long before it finishes. WTH? First things first, since RSS can be a variety of things, I checked /proc/$pid/smaps and confirmed that most of it was, indeed, the heap. That s the point where you reach for Google, type something like python memory profile and find various tools. One from the results that I remembered having used in the past is guppy s heapy. Armed with pdb, I broke execution in the middle of the slope, and tried to get memory stats with heapy. SIGSEGV. Ouch. Let s try something else. I reached out to objgraph and pympler. SIGSEGV. Ouch again. Tried working around the crashes for a while (too long while, retrospectively, hindsight is 20/20), and was somehow successful at avoiding them by peaking at a smaller set of objects. But whatever I did, despite being attached to a process that had 2.6GB RSS, I wasn t able to find more than 1.3GB of data. This wasn t adding up. It surely didn t help that getting to that point took close to an hour each time. Retrospectively, I wish I had investigated using something like Checkpoint/Restore in Userspace. Anyways, after a while, I decided that I really wanted to try to see the whole picture, not smaller peaks here and there that might be missing something. So I resolved myself to look at the SIGSEGV I was getting when using pympler, collecting a core dump when it happened. Guess what? The Debian python-dbg package does not contain the debug symbols for the python package. The core dump was useless. Since I was expecting I d have to fix something in python, I just downloaded its source and built it. Ran the command again, waited, and finally got a backtrace. First Google hit for the crashing function? The exact (unfixed) crash reported on the python bug tracker. No patch. Crashing code is doing:

((f)->f_builtins != (f)->f_tstate->interp->builtins)

And (f)->f_tstate is NULL. Classic NULL deref. Added a guard (assessing it wouldn t break anything). Ran the command again. Waited. Again. SIGSEGV. Facedesk. Another crash on the same line. Did I really use the patched python? Yes. But this time (f)->f_tstate->interp is NULL. Sigh. Same player, shoot again. Finally, no crash but still stuck on only 1.3GB accounted for. Ok, I know not all python memory profiling tools are entirely reliable, let s try heapy again. SIGSEGV. Sigh. No debug info on the heapy module, where the crash happens. Sigh. Rebuild the module with debug info, try again. The backtrace looks like heapy is recursing a lot. Look at %rsp, compare with the address space from /proc/$pid/maps. Confirmed. A stack overflow. Let s do ugly things and increase the stack size in brutal ways. Woohoo! Now heapy tells me there s even less memory used than the 1.3GB I found so far. Like, half less. Yeah, right. I m not clear on how I got there, but that s when I found gdb-heap, a tool from Red Hat s David Malcolm, and the associated talk Dude, where s my RAM? A deep dive into how Python uses memory (slides). With a gdb attached, I would finally be able to rip python s guts out and find where all the memory went. Or so I thought. The gdb-heap tool only found about 600MB. About as much as heapy did, for that matter, but it could be coincidental. Oh. Kay. I don t remember exactly what went through my mind then, but, since I was attached to a running process with gdb, I typed the following on the gdb prompt:

gdb> call malloc_stats()

And that s when the truth was finally unvealed: the memory allocator was just acting up the whole time. The ouput was something like:

Arena 0:
system bytes    =  some number above (but close to) 2GB
in use bytes    =  some number above (but close to) 600MB

Yes, the glibc allocator was just telling it had allocated 600MB of memory, but was holding onto 2GB. I must have found a really bad allocation pattern that causes massive fragmentation. One thing that David Malcolm s talk taught me, though, is that python uses its own allocator for small sizes, so the glibc allocator doesn t know about them. And, roughly, adding the difference between RSS and what glibc said it was holding to to the use bytes it reported somehow matches the 1.3GB I had found so far. So it was time to see how those things evolved in time, during the entire clone process. I grabbed some new data, tracking the evolution of system bytes and in use bytes . There are two things of note on this data:

• There is a relatively large gap between what the glibc allocator says it has gotten from the system, and the RSS (minus shared ) size, that I m expecting corresponds to the small allocations that python handles itself.
• Actual memory use is going down during the Import manifests phase, contrary to what the evolution of RSS suggests.

In fact, the latter is exactly how git-cinnabar is supposed to work: It reads changesets and manifests chunks, and holds onto them while importing files. Then it throws away those manifests and changesets chunks one by one while it imports them. There is, however, some extra bookkeeping that requires some additional memory, but it s expected to be less memory consuming than keeping all the changesets and manifests chunks in memory. At this point, I thought a possible explanation is that since both python and glibc are mmap()ing their own arenas, they might be intertwined in a way that makes things not go well with the allocation pattern happening during the Import manifest phase (which, in fact, allocates and frees increasingly large buffers for each manifest, as manifests grow in size in the mozilla-central history). To put the theory at work, I patched the python interpreter again, making it use malloc() instead of mmap() for its arenas. Aha! I thought. That definitely looks much better. Less gap between what glibc says it requested from the system and the RSS size. And, more importantly, no runaway increase of memory usage in the middle of nowhere. I was preparing myself to write a post about how mixing allocators could have unintended consequences. As a comparison point, I went ahead and ran another test, with the python allocator entirely disabled, this time. Heh. It turns out glibc was acting up all alone. So much for my (plausible) theory. (I still think mixing allocators can have unintended consequences.) (Note, however, that the reason why the python allocator exists is valid: without it, the overall clone took almost 10 more minutes) And since I had been getting all this data with 0.4.0, I gathered new data without the python allocator with the master branch. This paints a rather different picture than the original data on that branch, with much less memory use regression than one would think. In fact, there isn t much difference, except for the spike at the end, which got worse, and some of the noise during the Import manifests phase that got bigger, implying larger amounts of temporary memory used. The latter may contribute to the allocation patterns that throw glibc s memory allocator off. It turns out tracking memory usage in python 2.7 is rather painful, and not all the tools paint a complete picture of it. I hear python 3.x is somewhat better in that regard, and I hope it s true, but at the moment, I m stuck with 2.7. The most reliable tool I ve used here, it turns out, is pympler. Or rebuilding the python interpreter without its allocator, and asking the system allocator what is allocated. With all this data, I now have some defined problems to tackle, some easy (the spike at the end of the clone), and some less easy (working around glibc allocator s behavior). I have a few hunches as to what kind of allocations are causing the runaway increase of RSS. Coincidentally, I m half-way through a refactor of the code dealing with manifests, and it should help dealing with the issue. But that will be the subject of a subsequent post.

I've written parts of this story in the past, but never in one place and never in much detail. So why not now? In 1982 my family moved house, so one morning I went to school and at lunch-time I had to walk home to a completely different house. We moved sometime towards the end of the year, and ended up spending lots of money replacing the windows of the new place. For people in York I was born in Farrar Street, Y010 3BY, and we moved to a place on Thief Lane, YO1 3HS. Being named as it was I "ironically" stole at least two street-signs and hung them on my bedroom wall. I suspect my parents were disappointed. Anyway the net result of this relocation, and the extra repairs meant that my sisters and I had a joint Christmas present that year, a ZX Spectrum 48k. I tried to find pictures of what we received but unfortunately the web doesn't remember the precise bundle. All together though we received:

• A tape-deck.
• A 48k ZX Spectrum, with its glorious rubber keys.
• A pack of 10 (?) cassette-tapes.
• The first six were definitely the Spectrum six-pack:
  • The classic Horizons tape.
  • A version of Scrabble.
  • Horace Goes Skiing
    • From the Horace series.
  • A version of Chess by Psion.
  • Make-a-Chip - A logic-demonstration.
  • Chequered Flag, also by PSION, which was a terrible racing game. (Mostly this was terrible because it was in no-way a race. There were zero other cars on the track.)

I know we also received Horace and the Spiders, and I have vague memories of some other things being included, including a Space Invaders clone. No doubt my parents bought them separately. Highlights of my Spectrum-gaming memories include R-Type, Strider, and the various "Dizzy" games. Some of the latter I remember very fondly. Unfortunately this Christmas was pretty underwhelming. We unpacked the machine, we cabled it up to the family TV-set - we only had the one, after all - and then proceeded to be very disappointed when nothing we did resulted in a successful game! It turns out our cassette-deck was not good enough. Being back in the 80s the shops were closed over Christmas, and my memory is that it was around January before we received a working tape-player/recorder, such that we could load games. Happily the computer came with manuals. I read one, skipping words and terms I didn't understand. I then read the other, which was the spiral-bound orange book. It contained enough examples and decent wording that I learned to write code in BASIC. Not bad for an 11/12 year old. Later I discovered that my local library contained "computer books". These were colourful books that promised "The Mystery of Silver Mounter", or "Write your own ADVENTURE PROGRAMS". But were largely dry books that contained nothing but multi-page listings of BASIC programs to type in. Often with adjustments that had to be made for your own computer-flavour (BASIC varying between different systems).

If you want to recapture the magic scroll to the foot of this Osbourne page and you can download them!

Later I taught myself Z80 Assembly Language, partly via the Spectrum manual and partly via such books as these two (which I still own 30ish years later):

• Understanding your Spectrum, Basic & Machine Code Programming.
  • by Dr Ian Logan
• An introduction to Z80 Machine Code.
  • R.A & J.W Penfold

Pretty much the only reason I continued down this path is because I wanted infinite/extra lives in the few games I owned. (Which were largely pirated via the schoolboy network of parents with cassette-copiers.) Eventually I got some of my l33t POKES printed in magazines, and received free badges from the magazines of the day such as Your Sinclair & Sinclair User. For example I was "Hacker of the Month" in the Your Sinclair issue 67 , Page 32, apparently because I "asked so nicely in my letter". Terrible scan is terrible:

• https://archive.org/stream/your-sinclair-67/YourSinclair_67_Jul_1991#page/n31/mode/2up

Anyway that takes me from 1980ish to 1984. The only computer I ever touched was a Spectrum. Friends had other things, and there were Sega consoles, but I have no memories of them. Suffice it to say that later when I first saw a PC (complete with Hercules graphics, hard drives, and similar sourcery, running GEM IIRC) I was pleased that Intel assembly was "similar" to Z80 assembly - and now I know the reason why. Some time in the future I might document how I got my first computer job. It is hillarious. As was my naivete.

Here s something you never want to see:

ZFS has detected a checksum error:
   eid: 138
 class: checksum
  host: alexandria
  time: 2017-01-29 18:08:10-0600
 vtype: disk

This means there was a data error on the drive. But it s worse than a typical data error this is an error that was not detected by the hardware. Unlike most filesystems, ZFS and btrfs write a checksum with every block of data (both data and metadata) written to the drive, and the checksum is verified at read time. Most filesystems don t do this, because theoretically the hardware should detect all errors. But in practice, it doesn t always, which can lead to silent data corruption. That s why I use ZFS wherever I possibly can. As I looked into this issue, I saw that ZFS repaired about 400KB of data. I thought, well, that was unlucky and just ignored it. Then a week later, it happened again. Pretty soon, I noticed it happened every Sunday, and always to the same drive in my pool. It so happens that the highest I/O load on the machine happens on Sundays, because I have a cron job that runs zpool scrub on Sundays. This operation forces ZFS to read and verify the checksums on every block of data on the drive, and is a nice way to guard against unreadable sectors in rarely-used data. I finally swapped out the drive, but to my frustration, the new drive now exhibited the same issue. The SATA protocol does include a CRC32 checksum, so it seemed (to me, at least) that the problem was unlikely to be a cable or chassis issue. I suspected motherboard. It so happened I had a 9211-8i SAS card. I had purchased it off eBay awhile back when I built the server, but could never get it to see the drives. I wound up not filling it up with as many drives as planned, so the on-board SATA did the trick. Until now. As I poked at the 9211-8i, noticing that even its configuration utility didn t see any devices, I finally started wondering if the SAS/SATA breakout cables were a problem. And sure enough I realized I had a reverse cable and needed a forward one. $14 later, I had the correct cable and things are working properly now. One other note: RAM errors can sometimes cause issues like this, but this system uses ECC DRAM and the errors would be unlikely to always manifest themselves on a particular drive. So over the course of this, had I not been using ZFS, I would have had several megabytes of reads with undetected errors. Thanks to using ZFS, I know my data integrity is still good.

After months of trying, I've finally got my hands on a Nintendo NES Classic Mini. It's everything I wish retropie was: simple, reliable, plug-and-play gaming. I didn't have a NES at the time, so the games are all mostly new to me (although I'm familiar with things like Super Mario Brothers). The two main complaints about the NES classic are the very short controller cable and the need to press the "reset" button on the main unit to dip in and out of games. Both are addressed by the excellent 8bitdo Retro Receiver for NES Classic bundle. You get a bluetooth dongle that plugs into the classic and a separate wireless controller. The controller is a replica of the original NES controller. However, they've added another two buttons on the right-hand side alongside the original "A" and "B", and two discrete shoulder buttons which serve as turbo-repeat versions of "A" and "B". The extra red buttons make it look less authentic which is a bit of a shame, and are not immediately useful on the NES classic (but more on that in a minute). With the 8bitdo controller, you can remotely activate the Reset button by pressing "Down" and "Select" at the same time. Therefore the whole thing can be played from the comfort of my sofa. That's basically enough for me, for now, but in the future if I want to expand the functionality of the classic, it's possible to mod it. A hack called "Hakchi2" lets you install additional NES ROMs; install retroarch-based emulator cores and thus play SNES, Megadrive, N64 (etc. etc.) games; as well as other hacks like adding "down+select" Reset support to the wired controller. If you were playing non-NES games on the classic, then the extra buttons on the 8bitdo become useful.

Here's what happened in the Reproducible Builds effort between Sunday February 26 and Saturday March 4 2017: Upcoming Events Ed Maste will present Reproducible Builds in FreeBSD at AsiaBSDCon 2017. Ximin Luo will present Reproducible builds, its uses and the future at Open Source Days in Copenhagen on March 18. Holger Levsen will give a talk at the German Unix User Group's "Fr hjahrsfachgespr ch" in Darmstadt, Germany, about Reproducible Builds everywhere on March 23. Verifying Software Freedom with Reproducible Builds will be presented by Vagrant Cascadian at Libreplanet2017 in Boston, March 25th-26th. Media coverage Aspiration Tech published a very detailed report on our Reproducible Builds World Summit 2016 in Berlin. Reproducible work in other projects Duncan published a very thorough post on the Rust Programming Language Forum about reproducible builds in the Rust compiler and toolchain. In particular, he produced a table recording the reproducibility of different build products under different individual variations, totalling 187 build+variation combinations. Packages reviewed and fixed, and bugs filed Chris Lamb:

• #856614 filed against dask.distributed.
• #856807 filed against node-mocha, forwarded and merged upstream
• #856834 filed against tendermint-go-rpc.
• #856860 filed against archvsync.

Dhole:

• #856257 filed against tunnelx.

Reviews of unreproducible packages 60 package reviews have been added, 8 have been updated and 13 have been removed in this week, adding to our knowledge about identified issues. 1 issue type has been added:

• timestamp_in_fonts_generated_by_opentype

Weekly QA work During our reproducibility testing, FTBFS bugs have been detected and reported by:

• Chris Lamb (3)

diffoscope development diffoscope 78 was uploaded to unstable and jessie-backports by Mattia Rizzolo. It included contributions from:

• Chris Lamb:
  • Make tests that call xxd work on jessie again. (Closes: #855239)
  • tests: Move normalize_zeros to more generic utils.data module.
• Brett Smith:
  • comparators.json: Catch bad JSON errors on Python pre-3.5. (Closes: #855233)
• Ed Maste:
  • Use BSD-style stat(1) on FreeBSD. (Closes: #855169)

In addition, the following changes were made on the experimental branch:

• Chris Lamb (4):
  • Tidy cbfs tests.
  • Correct "exercice" -> "exercise" typo.
  • Support newer versions of cbfstool to avoid test failure. (Closes: #856446)
  • Skip icc test that varies on endian if the (Debian-specific) patch is not present. (Closes: #856447)

reproducible-website development

• anonmos1:
  • Replace root with 0 when giving UIDs/GIDs to GNU tar.
• Holger Levsen and Chris Lamb:
  • Publish report by Aspiration Tech about RWS Berlin 2016.

tests.reproducible-builds.org

• Ed Maste continued his work on testing FreeBSD for reproducibility but hasn't reached the magical 100% mark yet.
• Holger Levsen adjusted the Debian builders scheduling frequency, mostly to adopt to armhf having become faster due to the two new nodes.

Misc. This week's edition was written by Ximin Luo, Chris Lamb, Holger Levsen & reviewed by a bunch of Reproducible Builds folks on IRC & the mailing lists.

As I announced in mailing lists a few days ago, the Debian SunCamp (DSC2017) is happening again this May. SunCamp different to most other Debian events. Instead of a busy schedule of talks, SunCamp focuses on the hacking and socialising aspect, without making it just a Debian party/vacation.

DSC2016 - Hacking and discussing

The idea is to have 4 very productive days, staying in a relaxing and comfy environment, working on your own projects, meeting with your team, or presenting to fellow Debianites your most recent pet project.

DSC2016 - Tincho talking about Prometheus

We have tried to make this event the simplest event possible, both for organisers and attendees. There will be no schedule, except for the meal times at the hotel. But these can be ignored too, there is a lovely bar that serves snacks all day long, and plenty of restaurants and caf s around the village. The SunCamp is an event to get work done, but there will be time for relaxing and socialising too.

DSC2016 - Well deserved siesta

DSC2016 - Playing P tanque

Do you fancy a hack-camp in a place like this? One of the things that makes the event simple, is that we have negotiated a flat price for accommodation that includes usage of all the facilities in the hotel, and optionally food. We will give you a booking code, and then you arrange your accommodation as you please, you can even stay longer if you feel like it! The rooms are simple but pretty, and everything has been renovated very recently. We are not preparing a talks programme, but we will provide the space and resources for talks if you feel inclined to prepare one. You will have a huge meeting room, divided in 4 areas to reduce noise, where you can hack, have team discussions, or present talks. Do you want to see more pictures? Check the full gallery

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Debian SunCamp 2017 Hotel Anabel, LLoret de Mar, Province of Girona, Catalonia, Spain May 18-21, 2017

---

Tempted already? Head to the wikipage and register now, it is only 2 months away! Please try to reserve your room before the end of March. The hotel has reserved a number of rooms for us until that time. You can reserve a room after March, but we can't guarantee the hotel will still have free rooms. Comment

To be honest, at this stage I'd actually prefer ads in Wikipedia to having ever more intrusive begging for donations. Please go away soon.

Over the years, administrating thousand of NFS mounting linux computers at the time, I often needed a way to detect if the machine was experiencing NFS hang. If you try to use df or look at a file or directory affected by the hang, the process (and possibly the shell) will hang too. So you want to be able to detect this without risking the detection process getting stuck too. It has not been obvious how to do this. When the hang has lasted a while, it is possible to find messages like these in dmesg:

nfs: server nfsserver not responding, still trying
nfs: server nfsserver OK

It is hard to know if the hang is still going on, and it is hard to be sure looking in dmesg is going to work. If there are lots of other messages in dmesg the lines might have rotated out of site before they are noticed. While reading through the nfs client implementation in linux kernel code, I came across some statistics that seem to give a way to detect it. The om_timeouts sunrpc value in the kernel will increase every time the above log entry is inserted into dmesg. And after digging a bit further, I discovered that this value show up in /proc/self/mountstats on Linux. The mountstats content seem to be shared between files using the same file system context, so it is enough to check one of the mountstats files to get the state of the mount point for the machine. I assume this will not show lazy umounted NFS points, nor NFS mount points in a different process context (ie with a different filesystem view), but that does not worry me. The content for a NFS mount point look similar to this:

[...]
device /dev/mapper/Debian-var mounted on /var with fstype ext3
device nfsserver:/mnt/nfsserver/home0 mounted on /mnt/nfsserver/home0 with fstype nfs statvers=1.1
        opts:   rw,vers=3,rsize=65536,wsize=65536,namlen=255,acregmin=3,acregmax=60,acdirmin=30,acdirmax=60,soft,nolock,proto=tcp,timeo=600,retrans=2,sec=sys,mountaddr=129.240.3.145,mountvers=3,mountport=4048,mountproto=udp,local_lock=all
        age:    7863311
        caps:   caps=0x3fe7,wtmult=4096,dtsize=8192,bsize=0,namlen=255
        sec:    flavor=1,pseudoflavor=1
        events: 61063112 732346265 1028140 35486205 16220064 8162542 761447191 71714012 37189 3891185 45561809 110486139 4850138 420353 15449177 296502 52736725 13523379 0 52182 9016896 1231 0 0 0 0 0 
        bytes:  166253035039 219519120027 0 0 40783504807 185466229638 11677877 45561809 
        RPC iostats version: 1.0  p/v: 100003/3 (nfs)
        xprt:   tcp 925 1 6810 0 0 111505412 111480497 109 2672418560317 0 248 53869103 22481820
        per-op statistics
                NULL: 0 0 0 0 0 0 0 0
             GETATTR: 61063106 61063108 0 9621383060 6839064400 453650 77291321 78926132
             SETATTR: 463469 463470 0 92005440 66739536 63787 603235 687943
              LOOKUP: 17021657 17021657 0 3354097764 4013442928 57216 35125459 35566511
              ACCESS: 14281703 14290009 5 2318400592 1713803640 1709282 4865144 7130140
            READLINK: 125 125 0 20472 18620 0 1112 1118
                READ: 4214236 4214237 0 715608524 41328653212 89884 22622768 22806693
               WRITE: 8479010 8494376 22 187695798568 1356087148 178264904 51506907 231671771
              CREATE: 171708 171708 0 38084748 46702272 873 1041833 1050398
               MKDIR: 3680 3680 0 773980 993920 26 23990 24245
             SYMLINK: 903 903 0 233428 245488 6 5865 5917
               MKNOD: 80 80 0 20148 21760 0 299 304
              REMOVE: 429921 429921 0 79796004 61908192 3313 2710416 2741636
               RMDIR: 3367 3367 0 645112 484848 22 5782 6002
              RENAME: 466201 466201 0 130026184 121212260 7075 5935207 5961288
                LINK: 289155 289155 0 72775556 67083960 2199 2565060 2585579
             READDIR: 2933237 2933237 0 516506204 13973833412 10385 3190199 3297917
         READDIRPLUS: 1652839 1652839 0 298640972 6895997744 84735 14307895 14448937
              FSSTAT: 6144 6144 0 1010516 1032192 51 9654 10022
              FSINFO: 2 2 0 232 328 0 1 1
            PATHCONF: 1 1 0 116 140 0 0 0
              COMMIT: 0 0 0 0 0 0 0 0
device binfmt_misc mounted on /proc/sys/fs/binfmt_misc with fstype binfmt_misc
[...]

The key number to look at is the third number in the per-op list. It is the number of NFS timeouts experiences per file system operation. Here 22 write timeouts and 5 access timeouts. If these numbers are increasing, I believe the machine is experiencing NFS hang. Unfortunately the timeout value do not start to increase right away. The NFS operations need to time out first, and this can take a while. The exact timeout value depend on the setup. For example the defaults for TCP and UDP mount points are quite different, and the timeout value is affected by the soft, hard, timeo and retrans NFS mount options. The only way I have been able to get working on Debian and RedHat Enterprise Linux for getting the timeout count is to peek in /proc/. But according to Solaris 10 System Administration Guide: Network Services, the 'nfsstat -c' command can be used to get these timeout values. But this do not work on Linux, as far as I can tell. I asked Debian about this, but have not seen any replies yet. Is there a better way to figure out if a Linux NFS client is experiencing NFS hangs? Is there a way to detect which processes are affected? Is there a way to get the NFS mount going quickly once the network problem causing the NFS hang has been cleared? I would very much welcome some clues, as we regularly run into NFS hangs.

Great news! The Netfilter project has been elected by Google to be a mentoring organization in this year Google Summer of Code program. Following the pattern of the last years, Google seems to realise and support the importance of this software project in the Linux ecosystem. I will be proudly mentoring some student this 2017 year, along with Eric Leblond and of course Pablo Neira. The focus of the Netfilter project has been in nftables for the last years, and the students joining our community will likely work on the new framework. For prospective students: there is an ideas document which you must read. The policy in the Netfilter project is to encourage students to send patches before they are elected to join us. Therefore, a good starting point is to subscribe to the mailing lists, download the git code repositories, build by hand the projects (compilation) and look at the bugzilla (registration required). Due to this type of internships and programs, I believe is interesting to note the ascending involvement of women in the last years. I can remember right now: Ana Rey (@AnaRB), Shivani Bhardwaj (@tuxish), Laura Garc a and Elise Lennion (blog). On a side note, Debian is not participating in GSoC this year :-(

Since I use this as base for other PHP packages like SimKolab, I ve updated my packaging example with:

• PHP 7 support (untested, as I need libapache2-mod-php5)
• tons more utility code for you to use
• a class autoloader, with example (build time, for now)
• (at build time) running a PHPUnit testsuite (unless nocheck)

The old features (Apache 2.2 and 2.4 support, dbconfig-common, etc.) are, of course, still there. Support for other webservers could be contributed by you, and I could extend the autoloader to work at runtime (using dpkg triggers) to include dependencies as packaged in other Debian packages. See, nobody needs composer ! Feel free to check it out, play around with it, install it, test it, send me improvement patches and feature requests, etc. it s here with a mirror at GitHub (since I wrote it myself and the licence is permissive enough anyway). This posting and the code behind it are sponsored by my employer tarent.

Conferences After quite a bit of work, we finally have the sponsorship brochure produced for GUADEC and GNOME.Asia. Huge thanks to everyone who helped, I m really pleased with the result. Again, if you or your company are interested in sponsoring us, please drop a mail to sponsors@guadec.org! Food and Games I like food, and I like games. So this week there was a couple of awesome sneak previews on the upcoming GNOME 3.24 release. Matthias Clasen posted about GNOME Recipes the 1.0 release tasty snacks are now available directly on the desktop, which means I can also view them when I m at the back of the house in the kitchen, where the wifi connection is somewhat spotty. Adrien Plazas also posted about GNOME Games now I can get my retro gaming fix easily. Signing things I was sent a package in the post, with lots of blank stickers and a couple of pens. I ve now signed a load of stickers, and my hand hurts. More details about exactly what this is about soon :)

On February 28th, GitHub published a brand new version of its Terms of Service (ToS). While the first draft announced earlier in February didn't generate much reaction, the new ToS raised concerns that they may break at least the spirit, if not the letter, of certain free-software licenses. Digging in further reveals that the situation is probably not as dire as some had feared. The first person to raise the alarm was probably Thorsten Glaser, a Debian developer, who stated that the "new GitHub Terms of Service require removing many Open Source works from it". His concerns are mainly about section D of the document, in particular section D.4 which states:

You grant us and our legal successors the right to store and display your Content and make incidental copies as necessary to render the Website and provide the Service.

Section D.5 then goes on to say:

[...] You grant each User of GitHub a nonexclusive, worldwide license to access your Content through the GitHub Service, and to use, display and perform your Content, and to reproduce your Content solely on GitHub as permitted through GitHub's functionality

ToS versus GPL The concern here is that the ToS bypass the normal provisions of licenses like the GPL. Indeed, copyleft licenses are based on copyright law which forbid users from doing anything with the content unless they comply with the license, which forces, among other things, "share alike" properties. By granting GitHub and its users rights to reproduce content without explicitly respecting the original license, the ToS may allow users to bypass the copyleft nature of the license. Indeed, as Joey Hess, author of git-annex, explained :

The new TOS is potentially very bad for copylefted Free Software. It potentially neuters it entirely, so GPL licensed software hosted on Github has an implicit BSD-like license

Hess has since removed all his content (mostly mirrors) from GitHub. Others disagree. In a well-reasoned blog post, Debian developer Jonathan McDowell explained the rationale behind the changes:

My reading of the GitHub changes is that they are driven by a desire to ensure that GitHub are legally covered for the things they need to do with your code in order to run their service.

This seems like a fair point to make: GitHub needs to protect its own rights to operate the service. McDowell then goes on to do a detailed rebuttal of the arguments made by Glaser, arguing specifically that section D.5 "does not grant [...] additional rights to reproduce outside of GitHub". However, specific problems arise when we consider that GitHub is a private corporation that users have no control over. The "Services" defined in the ToS explicitly "refers to the applications, software, products, and services provided by GitHub". The term "Services" is therefore not limited to the current set of services. This loophole may actually give GitHub the right to bypass certain provisions of licenses used on GitHub. As Hess detailed in a later blog post:

If Github tomorrow starts providing say, an App Store service, that necessarily involves distribution of software to others, and they put my software in it, would that be allowed by this or not? If that hypothetical Github App Store doesn't sell apps, but licenses access to them for money, would that be allowed under this license that they want to my software?

However, when asked on IRC, Bradley M. Kuhn of the Software Freedom Conservancy explained that "ultimately, failure to comply with a copyleft license is a copyright infringement" and that the ToS do outline a process to deal with such infringement. Some lawyers have also publicly expressed their disagreement with Glaser's assessment, with Richard Fontana from Red Hat saying that the analysis is "basically wrong". It all comes down to the intent of the ToS, as Kuhn (who is not a lawyer) explained:

any license can be abused or misused for an intent other than its original intent. It's why it matters to get every little detail right, and I hope Github will do that.

He went even further and said that "we should assume the ambiguity in their ToS as it stands is favorable to Free Software". The ToS are in effect since February 28th; users "can accept them by clicking the broadcast announcement on your dashboard or by continuing to use GitHub". The immediacy of the change is one of the reasons why certain people are rushing to remove content from GitHub: there are concerns that continuing to use the service may be interpreted as consent to bypass those licenses. Hess even hosted a separate copy of the ToS [PDF] for people to be able to read the document without implicitly consenting. It is, however, unclear how a user should remove their content from the GitHub servers without actually agreeing to the new ToS.

CLAs When I read the first draft, I initially thought there would be concerns about the mandatory Contributor License Agreement (CLA) in section D.5 of the draft:

[...] unless there is a Contributor License Agreement to the contrary, whenever you make a contribution to a repository containing notice of a license, you license your contribution under the same terms, and agree that you have the right to license your contribution under those terms.

I was concerned this would establish the controversial practice of forcing CLAs on every GitHub user. I managed to find a post from a lawyer, Kyle E. Mitchell, who commented on the draft and, specifically, on the CLA. He outlined issues with wording and definition problems in that section of the draft. In particular, he noted that "contributor license agreement is not a legal term of art, but an industry term" and "is a bit fuzzy". This was clarified in the final draft, in section D.6, by removing the use of the CLA term and by explicitly mentioning the widely accepted norm for licenses: "inbound=outbound". So it seems that section D.6 is not really a problem: contributors do not need to necessarily delegate copyright ownership (as some CLAs require) when they make a contribution, unless otherwise noted by a repository-specific CLA. An interesting concern he raised, however, was with how GitHub conducted the drafting process. A blog post announced the change on February 7th with a link to a form to provide feedback until the 21st, with a publishing deadline of February 28th. This gave little time for lawyers and developers to review the document and comment on it. Users then had to basically accept whatever came out of the process as-is. Unlike every software project hosted on GitHub, the ToS document is not part of a Git repository people can propose changes to or even collaboratively discuss. While Mitchell acknowledges that "GitHub are within their rights to update their terms, within very broad limits, more or less however they like, whenever they like", he sets higher standards for GitHub than for other corporations, considering the community it serves and the spirit it represents. He described the process as:

[...] consistent with the value of CYA, which is real, but not with the output-improving virtues of open process, which is also real, and a great deal more pleasant.

Mitchell also explained that, because of its position, GitHub can have a major impact on the free-software world.

And as the current forum of preference for a great many developers, the knock-on effects of their decisions throw big weight. While GitHub have the wheel and they ve certainly earned it for now they can do real damage.

In particular, there have been some concerns that the ToS change may be an attempt to further the already diminishing adoption of the GPL for free-software projects; on GitHub, the GPL has been surpassed by the MIT license. But Kuhn believes that attitudes at GitHub have begun changing:

GitHub historically had an anti-copyleft culture, which was created in large part by their former and now ousted CEO, Preston-Warner. However, recently, I've seen people at GitHub truly reach out to me and others in the copyleft community to learn more and open their minds. I thus have a hard time believing that there was some anti-copyleft conspiracy in this ToS change.

GitHub response However, it seems that GitHub has actually been proactive in reaching out to the free software community. Kuhn noted that GitHub contacted the Conservancy to get its advice on the ToS changes. While he still thinks GitHub should fix the ambiguities quickly, he also noted that those issues "impact pretty much any non-trivial Open Source and Free Software license", not just copylefted material. When reached for comments, a GitHub spokesperson said:

While we are confident that these Terms serve the best needs of the community, we take our users' feedback very seriously and we are looking closely at ways to address their concerns.

Regardless, free-software enthusiasts have other concerns than the new ToS if they wish to use GitHub. First and foremost, most of the software running GitHub is proprietary, including the JavaScript served to your web browser. GitHub also created a centralized service out of a decentralized tool (Git). It has become the largest code hosting service in the world after only a few years and may well have become a single point of failure for free software collaboration in a way we have never seen before. Outages and policy changes at GitHub can have a major impact on not only the free-software world, but also the larger computing world that relies on its services for daily operation. There are now free-software alternatives to GitHub. GitLab.com, for example, does not seem to have similar licensing issues in its ToS and GitLab itself is free software, although based on the controversial open core business model. The GitLab hosting service still needs to get better than its grade of "C" in the GNU Ethical Repository Criteria Evaluations (and it is being worked on); other services like GitHub and SourceForge score an "F". In the end, all this controversy might have been avoided if GitHub was generally more open about the ToS development process and gave more time for feedback and reviews by the community. Terms of service are notorious for being confusing and something of a legal gray area, especially for end users who generally click through without reading them. We should probably applaud the efforts made by GitHub to make its own ToS document more readable and hope that, with time, it will address the community's concerns.

Note: this article first appeared in the Linux Weekly News.