Search Results: "spa"

4 June 2020

Gunnar Wolf: Tor from Telmex. When I say achievement unlocked , I mean it!

### The blockade has ended! For some introduction.. Back in 2016, Telmex Mexico's foremost communications provider and, through the brands grouped under the *Am rica M vil* brand, one of Latin America's most important ISPs set up rules to block connecitons to (at least) seven of Tor's *directory authorities* (*DirAuths*). We believe they might have blocked all of them, in an attempt to block connections from Tor from anywhere in their networks, but Tor is much more resourceful than that so, the measure was not too effective. Only... _Some_ blocking did hurt Telmex's users: The ability to play an active role in Tor. The ability to host Tor relays at home. Why? Because the *consensus protocol* requires relays to be reachable in order to be measured from the network's *DirAuths*. ### Technical work to prove the blocking We dug into the issue as part of the work we carried out in the project I was happy to lead between 2018 and 2019, *UNAM/DGAPA/PAPIME PE102718*. In March 2019, I presented a paper titled [Distributed Detection of Tor Directory Authorities Censorship in Mexico](https://www.thinkmind.org/index.php?view=article&articleid=icn_2019_6_20_38010) ([alternative download](http://ru.iiec.unam.mx/4538/) in the [Topic on Internet Censorship and Surveillance (TICS) track](https://tics.site/) of the XVIII International Conference on Networks. Then... We had many talks inside our group, but nothing seemed to move for several months. We did successfully push for increasing the number of Tor relays in Mexico (we managed to go from two to eleven stable relays not much in absolute terms, but quite good relatively, even more considering most users were not technically able to run one!) Jacobo N jera, journalist participant of our project, didn't leave things there just lying around waiting magically for justice to happen. Together with Vasilis Ververis, from the [Magma Project](https://magma.lavafeld.org/), they presented some weeks ago a [Case study: Tor Directory Authorities Censorship in Mexico](https://magma.lavafeld.org/guide/data-analysis.html#case-study-tor-directory-authorities-censorship-in-mexico). ### Pushing to action But a good part of being a journalist is knowing _how_ and _when_ to spread the word. Having already two technical studies showing the blocking in place, Jacobo presented his findings with [an article in GlobalVoices: *The largest telecommunications operator in Mexico blocks the secure network*](https://es.globalvoices.org/2020/05/28/en-mexico-el-mas-grande-operador-de-telecomunicaciones-bloquea-la-internet-segura/). Surprisingly (to me, at least), this story was picked up by a major Mexican newspaper: The same evening the story hit GlobalVoices, [Rodrigo Riquelme](https://www.eleconomista.com.mx/autor/rriquelme) posted an article, in the Technology section of *El Economista*, titled [Telmex blocks seven out of ten accesses to the Tor network in Mexico](https://www.eleconomista.com.mx/tecnologia/Telmex-bloquea-siete-de-10-accesos-a-la-red-Tor-en-Mexico-20200528-0078.html). And that very same day, Telmex sent a reply I am translating in full (that is now included at the end of Riquelme's article): > Mexico City, May 28, 2020 > > In relation to Tor navigation from TELMEX's network, the company > informs: > > In TELMEX, we are committed to the full respect to navigation > freedom for all of our users. > > TELMEX practices no application-level blocking policies; the Tor > application, as well as the rest of Internet applications, can be > freely accessed from our network. > > In order to protect the Internauts' information, the seven refered > nodes were in their time reported because they were associated with > the distribution of the WannaCry ransomware, which is the reason > they were filtered, but this does not hamper the use of the Tor > application. ### So we got an answer...? Jacobo knew we had to take advantage of this answer, and act fast! He entered rush-writing mode and, with the help of our good friend and lawyer Salvador Alc ntar, we wrote [a short letter to Renato Flores Cartas, Corporative Communication of Am rica M vil](https://internetanonima.net/respuesta-a-telmex-sobre-la-red-tor-en-mexico/), and sent it on June 1st. Next thing I know, this evening Jacobo was asking me if I could confirm the blocking was lifted. What I could not believe it! But, yes Today Jacobo published the confirmation that [the seven blocked IP routes were finally reachable again from ASN 8151 (UNINET / Telmex / Am rica M vil)!](https://internetanonima.net/confirmamos-desbloqueo-de-las-7-direcciones-de-la-red-tor-por-telmex/) Of course, this story was picked up again by El Economista [Telmex unblocks IP addresses for the Tor network's directory authority server IPs in Mexico](https://www.eleconomista.com.mx/tecnologia/Telmex-desbloquea-direcciones-IP-de-servidores-de-autoridad-de-la-red-Tor-en-Mexico-20200604-0094.html). ### Wrapping up How can I put this in words? I am very, very, very, *very, very, very*, **very, very, very** happy we managed to see this through! Although we have been pushing for increasing the usage of Tor among users at risk in Mexico Being a journalist, defending human rights, are still a high-risk profession in my country. We strongly believe in this, and will continue trying to raise awareness of the usage. But, just as with free software, *using* network anonymization tools is not all. We need more people to become active, to become engaged, to *become active participants* in anonymization. As the adage says, *anonymity loves company* In order to build strong, sufficient anonymization capability for everybody that needs it, we need more people to *provide relay services*. And this is a *huge* step to improve Mexico's participation in the Tor network! --- Image credits: [*Seeing My World Through a Keyhole*, by Kate Ter Haar](https://www.flickr.com/photos/katerha/4592429363) (CC-BY); [Tor logo (Wikimedia Commons)](https://commons.wikimedia.org/wiki/File:Tor-logo-2011-flat.svg)

3 June 2020

Keith Packard: picolibc-ryu

Float/String Conversion in Picolibc: Enter Ry I recently wrote about this topic having concluded that the best route for now was to use the malloc-free, but imprecise, conversion routines in the tinystdio alternative. A few days later, Sreepathi Pai pointed me at some very recent work in this area: This is amazing! Thirty years after the papers referenced in the previous post, Ulf Adams came up with some really cool ideas and managed to reduce the math required for 64-bit conversion to 128 bit integers. This is a huge leap forward; we were doing long multi-precision computations before, and now it's all short enough to fit in registers (ok, a lot of registers, but still). Getting the Ry Code The code is available on github: https://github.com/ulfjack/ryu. Reading through it, it's very clear that the author focuses on performance with lots of tuning for common cases. Still, it's quite readable, especially compared with the newlib multi-precision based code. Picolibc String/Float conversion interface Picolibc has some pretty basic needs for the float/string conversion code, it wants four functions:
  1. __dtoa_engine 
    int
__dtoa_engine(double x, struct dtoa *dtoa, uint8_t max_digits, uint8_t max_decimals);
    This converts the double x to a string of decimal digits and a decimal exponent stored inside the 'dtoa' struct. It limits the total number of digits to max_digits and, optionally (when max_decimals is non-zero), limits the number of fractional digits to max_decimals - 1. This latter supports 'f' formats. Returns the number of digits stored, which is <= max_digits. Less if the number can be accurately represented in fewer digits.
  2. __ftoa_engine 
    int
__ftoa_engine(float x, struct ftoa *ftoa, uint8_t max_digits, uint8_t max_decimals);
    The same as __dtoa_engine, except for floats.
  3. __atod_engine 
    double
__atod_engine(uint64_t m10, int e10);
    To avoid needing to handle stdio inside the conversion function, __atod_engine receives fully parsed values, the base-10 significand (m10) and exponent (e10). The value to convert is m10 * pow(10, e10).
  4. __atof_engine 
    float
__atof_engine(uint32_t m10, int e10);
    The same as __atod_engine, except for floats.
With these, it can do printf, scanf, ecvt, fcvt, gcvt, strtod, strtof and atof. Porting Ry to Picolibc The existing Ry float-to-string code always generates the number of digits necessary for accurate output. I had to hack it up to generate correctly rounded shorter output when max_digits or max_decimals were smaller. I'm not sure I managed to do that correctly, but at least it appears to be passing all of the test cases I have. In normal operation, Ry iteratively removes digits from the answer that aren't necessary to disambiguate with neighboring values. What I changed was to keep removing digits using that method until the answer had few enough digits to fit in the desired length. There's some tricky rounding code that adjusts the final result and I had to bypass that if I'd removed extra digits. That was about the only change necessary to the core algorithm. I also trimmed the code to only include the general case and not the performance improvements, then wrapped it with code to provide the _engine interface. On the string-to-float side, most of what I needed to do was remove the string parsing bits at the start of the function and switch from performance-optimized to space-optimized versions of a couple of internal routines. Correctness Results Because these new functions are now 'exact', I was able to adjust the picolibc tests to compare all of the bits for string/float conversion instead of having to permit a bit of slop in the answers. With those changes, the picolibc test suite passes, which offers some assurance that things aren't completely broken. Size Results Snek uses the 32-bit float versions of the conversion routines, and for that, the size difference is: 
   text    data     bss     dec     hex filename
  59068      44   37968   97080   17b38 snek-qemu-riscv-orig.elf
  59430      44   37968   97442   17ca2 snek-qemu-riscv-ryu.elf
    362
362 bytes added to gain accurate printf/strtof results seems like a good trade-off in this case. Performance I haven't measured performance at all, but I suspect that it won't be nearly as problematic on most platforms as the source code makes it appear. And that's because Ry is entirely integer arithmetic with no floating point at all. This avoids using the soft fp code for platforms without hardware float support. Pointers to the Code I haven't merged this to picolibc master yet, it's on the ryu branch: Review, especially of the hack above to return short results, would be greatly appreciated! Thanks again to Ulf Adams for creating this code and to Sreepathi Pai for sending me a note about it!

2 June 2020

Olivier Berger: Mixing NRELab s Antidote and Eclipse Che on the same k8s cluster

You may have heard of my search for Cloud solutions to run labs in an academic context, with a focus on free an open source solutions . You may read previous installments of this blog, or for a shorter, check the presentation I ve recorded last week. I ve become quite interested, in the latest month, in 2 projects: NRELab s Antidote and Eclipse Che. Antidote is the software that powers NRELabs, a labs platform for learning network automation, which runs on top of Kubernetes (k8s). The interesting thing is that for each learner, there can be a dedicated k8s namespace with multiple virtual nodes running on a separate network. This can be used in the context of virtual classes/labs where our students will perform network labs in parallel on the same cluster. Eclipse Che powers Eclipse on the Cloud , making available software development environments, for developers, on a Kubernetes Cloud. Developers typically work from a Web page instead of installing local development tools. Both projects seem quite complementary. For one, we both teach networks and software developments. So that would naturally appeal for many professors. Furthermore, Eclipse Che provides a few features that Antidote is lacking : authenticating users (with keycloak), and persisting their work in workspaces, between work sessions. Typically what we need in our academic context where students will work on the same labs during scheduled classes, week after week, during or off-hours. Thus it would be great to have more integration between the 2 environments. I intend to work on that front, but that takes time, as running stuff on Kubernetes isn t exactly trivial, at least when you re like me and want to use a vanilla kubernetes. I ve mainly relied on running k8s inside VMs using Vagrant and/or minikube so far. A first milestone I ve achieved is making sure that Antidote and Eclipse Che aren t incompatible. Antidote s selfmedicate script was actually running inside a Vagrant VM, where I had difficulties installing Eclipse Che (probably because of old software, or particular networking setup details). I ve overcome this hurdle, as I m now able to install both environments on a single Kubernetes VM (using my own Vagrant setup). Running Eclipse Che (alongsite Antidote) on a k8s Vagrant VM. This proves only that there s no show stopper there, but a lot of work remains. Stay tuned. Update: I ve finally managed to get it to work on the antidote-selfmedicate base too. See my branch at: https://github.com/olberger/antidote-selfmedicate/tree/che

Sylvestre Ledru: Debian rebuild with clang 10 + some patches

Because of the lock-down in France and thanks to Lucas, I have been able to make some progress rebuilding Debian with clang instead of gcc.

TLDR Instead of patching clang itself, I used a different approach this time: patching Debian tools or implementing some workaround to mitigate an issue.
The percentage of packages failing drop from 4.5% to 3.6% (1400 packages to 1110 - on a total of 31014). I focused on two classes of issues:

Qmake As I have no intention to merge the patch upstream, I used a very dirty workaround. I overwrote the g++ qmake file by clang's:
https://salsa.debian.org/lucas/collab-qa-tools/-/blob/master/modes/clang10#L44-47 I dropped the number of this failure to 0, making some packages build flawlessly (example: qtcreator, chessx, fwbuilder, etc). However, some packages are still failing later and therefore increasing the number of failures in some other categories like link error. For example, qtads fails because of ordered comparison between pointer and zero or oscar fails on a -Werror,-Wdeprecated-copy error. Breaking the build later also highlighted some new classes of issues which didn't occur with clang < 10.
For example, warnings related to C++ range loop or implicit int float conversion (I fixed a bunch of them in Firefox) .

Symbol differences Historically, symbol management for C++ in Debian has been a pain. Russ Allbery wrote a blog post in 2012 explaining the situation. AFAIK, it hasn't changed much.
Once more, I took the dirty approach: if there new or missing symbols, don't fail the build.
The rational is the following: Packages in the Debian archive are supposed to build without any issue. If there is new or missing symbols, it is probably clang generating a different library but this library is very likely working as expected (and usable by a program compiled with g++ or clang). It is purely a different approach taken by the compiler developer. In order to mitigate this issue, before the build starts, I am modifying dpkg-gensymbols to transform the error into a warning.
So, the typical Debian error some new symbols appeared in the symbols file or some symbols or patterns disappeared in the symbols file will NOT fail the build. Unsurprisingly, all but one package (libktorrent) build. Even if I am pessimistic, I reported a bug on dpkg-dev to evaluate if we could improve dpkg-gensymbol not to fail on these cases.

Next steps The next offender is Imake.tmpl:2243:10: fatal error: ' X11 .rules' file not found with more than an hundred occurrences, reported upstream quite sometime ago. Then, the big issues are going to be much harder to fix as they are real issues/warnings (with -Werror) in the code of the packages. Example: -Wc++11-narrowing & Wreserved-user-defined-literal... The list is long.
I will probably work on that when llvm/clang 11 are in RC phase.

For maintainers & upstream Maintainer of Debian/Ubuntu packages? I am providing a list of failing packages per maintainer: https://clang.debian.net/maintainers.php
For upstream, it is also easy to test with clang. Usually, apt install clang && CC=clang CXX=clang++ <build step> is good enough.

Conclusion With these two changes, I have been able to fix about 290 packages. I think I will be able to get that down a bit more but we will soon reach a plateau as many warnings/issues will have to fix in the C/C++ code itself.

Lisandro Dami n Nicanor P rez Meyer: Simplified Monitoring of Patients in Situations of Mass Hospitalization (MoSimPa) - Fighting COVID-19

I have been quite absent from Debian stuff lately, but this increased since COVID-19 hits us. In this blog post I'll try to sketch what I have been doing to help fight COVID-19 this last few months.

In the beginningWhen the pandemic reached Argentina the government started a quarantine. We engineers (like engineers around the world) started to think on how to put our abilities in order to help with the situation. Some worked toward providing more protection elements to medical staff, some towards increasing the number of ventilation machines at disposal. Another group of people started thinking on another ways of helping. In Bah a Blanca arised the idea of monitoring some variables remotely and in masse.

Simplified Monitoring of Patients in Situations of Mass Hospitalization (MoSimPa)

This is where the idea of remotely monitored devices came in, and MoSimPa (from the spanish of "monitoreo simplificado de pacientes en situaci n de internaci n masiva") started to get form. The idea is simple: oximetry (SpO2), heart rate and body temperature will be recorded and, instead of being shown in a display in the device itself, they will be transmitted and monitored in one or more places. In this way medical staff doesn't has to reach a patient constantly and monitoring could be done by medical staff for more patients at the same time. In place monitoring can also happen using a cellphone or tablet.

The devices do not have a screen of their own and almost no buttons, making them more cheap to build and thus more in line with the current economic reality of Argentina.


This is where the project Para Ayudar was created. The project aims to produce the aforementioned non-invasive device to be used in health institutions, hospitals, intra hospital transports and homes.

It is worth to note that the system is designed as a complementary measure for continuous monitoring of a pacient. Care should be taken to check that symptomps and overall patient status don't mean an inmediate life threat. In other words, it is NOT designed for ICUs.

All the above done with Free/Libre/Open Source software and hardware designs. Any manufacturing company can then use them for mass production.

The importance of early pneumonia detection


We were already working in MoSimPa when an NYTimes article caught or attention: "The Infection That s Silently Killing Coronavirus Patients". From the article:

A vast majority of Covid pneumonia patients I met had remarkably low oxygen saturations at triage seemingly incompatible with life but they were using their cellphones as we put them on monitors. Although breathing fast, they had relatively minimal apparent distress, despite dangerously low oxygen levels and terrible pneumonia on chest X-rays.

This greatly reinforced the idea we were on the right track.

The project from a technical standpoint


As the project is primarily designed for and by Argentinians the current system design and software documentation is written in spanish, but the source code (or at least most of it) is written in english. Should anyone need it in english please do not hesitate in asking me.

General system description

System schema

The system is comprised of the devices, a main machine acting as a server (in our case for small setups a Raspberry Pi) and the possibility of accessing data trough cell phones, tablets or other PCs in the network.

The hardware


As of today this is the only part in which I still can't provide schematics, but I'll update this blog post and technical doc with them as soon as I get my hands into them.

Again the design is due to be built in Argentina where getting our hands on hardware is not easy. Moreover it needs to be as cheap as possible, specially now that the Argentinian currency, the peso, is every day more depreciated. So we decided on using an ESP32 as the main microprocessor and a set of Maxim sensors devices. Again, more info when I have them at hand.

The software


Here we have many more components to describe. Firstly the ESP32 code is done with the Arduino SDK. This part of the stack will receive many updates soon, as soon as the first hardware prototypes are out.

For the rest of the stack I decided to go ahead with whatever is available in Debian stable. Why? Well, Raspbian provides a Debian stable-based image and I'm a Debian Developer, so things should go just natural for me in that front. Of course each component has its own packaging. I'm one of Debian's Qt maintainers then using Qt will also be quite natural for me. Plots? Qwt, of course. And with that I have most of my necessities fulfilled. I choose PostgreSql as database server and Mosquitto as MQTT broker.

Between the database and MQTT is mosimpa-datakeeper. The piece of software from which medical staff monitor patients is unsurprisingly called mosimpa-monitor.

mosimpa-monitor
MoSimPa's monitor main screen

mosimpa-monitor plots
Plots of a patient's data


mosimpa-monitor-alarms-setup
Alarm thresholds setup


And for managing patients, devices, locations and internments (CRUD anyone?) there is currently a Qt-based application called mosimpa-abm.

mosimpa-abm
ABM main screen


mosimpa-abm-internments
ABM internments view

The idea is to replace it with a web service so it doesn't needs to be confined to the RPi or require installations in other machines. I considered using webassembly but I would have to also build PostgreSql in order to compile Qt's plugin.

Translations? Of course! As I have already mentioned the code is written in English. Qt allows to easily translate applications, so I keep a Spanish one as the code changes (and we are primarily targeting spanish-speaking people). But of course this also means it can be easily translated to whichever language is necessary.

Even if I am a packager I still have some stuff to fix from the packaging itself, like letting datakeeper run with its own user. I just haven't got to it yet.


A video showing the software in action

Certifications


We are working towards getting the system certified by ANMAT, which is the Argentinian equivalent for EEUU's FDA.

Funding


While all the people involved are working ad-honorem funding is still required in order to buy materials, create the prototypes, etc. The project created payments links with Mercado Pago (in spanish and argentinian pesos) and other bank methods (PDF, also in spanish).

I repeat the links here with an aproximation to US$.

- 500 AR$ (less than 8 US$)
- 1000 AR$ (less than 15 US$)
- 2000 AR$ (less than 30 US$)
- 3000 AR$ (less than 45 US$)
- 5000 AR$ (less than 75 US$)

You can check the actual convertion rate in https://www.google.com/search?q=argentine+peso+to+us+dollars

The project was also presented at a funding call of argentinian Agencia de Promoci n de la Investigaci n, el Desarrollo Tecnol gico y la Innovaci n (Agencia I+D+i). 900+ projects where presented and 64 funded, MoSimPa between them.

Sylvain Beucler: Debian LTS and ELTS - May 2020

Debian LTS Logo Here is my transparent report for my work on the Debian Long Term Support (LTS) and Debian Extended Long Term Support (ELTS), which extend the security support for past Debian releases, as a paid contributor. In May, the monthly sponsored hours were split evenly among contributors depending on their max availability - I was assigned 17.25h for LTS (out of 30 max; all done) and 9.25h for ELTS (out of 20 max; all done). A survey will be published very shortly to gather feedback from all parties involved in LTS (users, other Debian teams...) -- let us know what you think, so we start the forthcoming new (Stretch) LTS cycle in the best conditions :) Discussion is progressing on funding & governance of larger LTS-related projects. Who should decide: contributors, Freexian, sponsors? Do we fund with a percentage or by capping resources allocated on security updates? I voiced concerns over funding these at the expense of smaller, more organic, more recurrent tasks that are less easy to specify but greatly contribute to the overall quality nevertheless. ELTS - Wheezy LTS - Jessie Documentation/Scripts

1 June 2020

Jonathan Carter: Free Software Activities for 2020-05

I would say that this was a crazy month, but with everything ever escalating, does that even mean anything anymore? I lost track of tracking my activities in the second half of the month, and I m still not very good at logging the soft stuff , that is, things like non-technical work but that also takes up a lot of time, but will continue to work on it.
Towards the end of the month I spent a huge amount of time on MiniDebConf Online, I m glad it all worked out, and will write a seperate blog entry on that. Thank you again to everyone for making it a success! I m also moving DPL activities to the DPL blog, so even though it s been a busy month in the free software world my activity log here will look somewhat deceptively short this month MiniDebConf Online 2020-05-06: Help prepare initial CfP mail. 2020-05-06: Process some feedback regarding accessibility on Jitsi.

Debian Packaging 2020-05-02: Upload package gnome-shell-extension-workspaces-to-dock (53-1) to Debian unstable. 2020-05-02: Upload package tetzle (2.1.6-1) to Debian unstable. 2020-05-06: Upload package bundlewrap (3.9.0-1) to Debian unstable. 2020-05-06: Accept MR#1 for connectagram. 2020-05-06: Upload package connectagram (1.2.11-1) to Debian unstable. 2020-05-07: Upload package gnome-shell-extension-multi-monitors (20-1) to Debian unstable (Closes: #956169). 2020-05-07: Upload package tanglet (1.5.6-1) to Debian unstable. 2020-05-16: Upload package calamares (3.2.24-1) to Debian unstable. 2020-05-16: Accept MR#1 for tuxpaint-config. 2020-05-16: Accept MR#7 for debian-live. 2020-05-18: Upload package bundlewrap (3.10.0) to Debian unstable.

Debian Mentoring 2020-05-02: Sponsor package gamemode (1.5.1-3) (Games team request). 2020-05-16: Sponsor package gamemode (1.5.1-4) (Games team request).

Paul Wise: FLOSS Activities May 2020

Focus This month I didn't have any particular focus. I just worked on issues in my info bubble.

Changes

Issues

Review

Administration
  • nsntrace: talk to upstream about collaborative maintenance
  • Debian: deploy changes, debug issue with GPS markers file generation, migrate bls/DUCK from alioth-archive to salsa
  • Debian website: ran map cron job, synced mirrors
  • Debian wiki: approve accounts, ping folks with bouncing email

Communication

Sponsors The apt-offline work and the libfile-libmagic-perl backports were sponsored. All other work was done on a volunteer basis.

31 May 2020

Chris Lamb: Free software activities in May 2020

Here is my monthly update covering what I have been doing in the free software world during May 2020 (previous month): In Lintian, the static analysis tool for Debian packages:
Reproducible builds One of the original promises of open source software is that distributed peer review and transparency of process results in enhanced end-user security. However, whilst anyone may inspect the source code of free and open source software for malicious flaws, almost all software today is distributed as pre-compiled binaries. This allows nefarious third-parties to compromise systems by injecting malicious code into ostensibly secure software during the various compilation and distribution processes. The motivation behind the Reproducible Builds effort is to ensure no flaws have been introduced during this compilation process by promising identical results are always generated from a given source, thus allowing multiple third-parties to come to a consensus on whether a build was compromised. The initiative is proud to be a member project of the Software Freedom Conservancy, a not-for-profit 501(c)(3) charity focused on ethical technology and user freedom. Conservancy acts as a corporate umbrella allowing projects to operate as non-profit initiatives without managing their own corporate structure. If you like the work of the Conservancy or the Reproducible Builds project, please consider becoming an official supporter.
Elsewhere in our tooling, I made the following changes to diffoscope, our in-depth and content-aware diff utility that can locate and diagnose reproducibility issues, including preparing and uploading versions 142, 143, 144, 145 and 146 to Debian: I also performed a huge overhaul of diffoscope's website:
Lastly, I made a large number of changes to the main Reproducible Builds website and documentation:
Debian LTS This month I contributed 17 hours to Debian Long Term Support (LTS) and 9 hours on its sister Extended LTS project. You can find out more about the two projects via the following video:
Debian I filed the following bug reports in Debian this month: I also filed a number of bugs against packages that are not compatible with Django 3.x, (organised around a single master bug) including django-taggit, sorl-thumbnail, django-simple-captcha, django-cas-server, django-cors-headers, python-django-csp, django-pipeline, python-django-jsonfield, python-django-contact-form, django-model-utils, django-fsm, django-modeltranslation, django-oauth-toolkit, libthumbor, python-django-extensions, python-django-imagekit, python-django-navtag, python-django-tagging, djangorestframework, django-haystack, django-taggit, django-simple-captcha, python-django-registration, python-django-pyscss, python-django-compressor, python-django-crispy-forms & python-django-mptt,
Lastly, I made the following uploads to Debian: I also sponsored an upload for adminer (4.7.7-1), also uploading it to buster-backports.

30 May 2020

Sean Whitton: GNU Emacs' Transient Mark mode

Something I ve found myself doing as the pandemic rolls on is picking out and (re-)reading through sections of the GNU Emacs manual and the GNU Emacs Lisp reference manual. This has got me (too) interested in some of the recent history of Emacs development, and I did some digging into archives of emacs-devel from 2008 (15M mbox) regarding the change to turn Transient Mark mode on by default and set mark-even-if-inactive to true by default in Emacs 23.1. It s not always clear which objections to turning on Transient Mark mode by default take into account the mark-even-if-inactive change. I think that turning on Transient Mark mode along with mark-even-if-inactive is a good default. The question that remains is whether the disadvantages of Transient Mark mode are significant enough that experienced Emacs users should consider altering Emacs default behaviour to mitigate them. Here s one popular blog arguing for some mitigations. How might Transient Mark mode be disadvantageous? The suggestion is that it makes using the mark for navigation rather than for acting on regions less convenient:
  1. setting a mark just so you can jump back to it (i) is a distinct operation you have to think of separately; and (ii) requires two keypresses, C-SPC C-SPC, rather than just one keypress
  2. using exchange-point-and-mark activates the region, so to use it for navigation you need to use either C-u C-x C-x or C-x C-x C-g, neither of which are convenient to type, or else it will be difficult to set regions at the place you ve just jumped to because you ll already have one active.
There are two other disadvantages that people bring up which I am disregarding. The first is that it makes it harder for new users to learn useful ways in which to use the mark when it s deactivated. This happened to me, but it can be mitigated without making any behavioural changes to Emacs. The second is that the visual highlighting of the region can be distracting. So far as I can tell, this is only a problem with exchange-point-and-mark, and it s subsumed by the problem of that command actually activating the region. The rest of the time Emacs automatic deactivation of the region seems sufficient. How might disabling Transient Mark mode be disadvantageous? When Transient Mark mode is on, many commands will do something usefully different when the mark is active. The number of commands in Emacs which work this way is only going to increase now that Transient Mark mode is the default. If you disable Transient Mark mode, then to use those features you need to temporarily activate Transient Mark mode. This can be fiddly and/or require a lot of keypresses, depending on exactly where you want to put the region. Without being able to see the region, it might be harder to know where it is. Indeed, this is one of the main reasons for wanting Transient Mark mode to be the default, to avoid confusing new users. I don t think this is likely to affect experienced Emacs users often, however, and on occasions when more precision is really needed, C-u C-x C-x will make the region visible. So I m not counting this as a disadvantage. How might we mitigate these two sets of disadvantages? Here are the two middle grounds I m considering. Mitigation #1: Transient Mark mode, but hack C-x C-x behaviour 
(defun spw/exchange-point-and-mark (arg)
  "Exchange point and mark, but reactivate mark a bit less often.

Specifically, invert the meaning of ARG in the case where
Transient Mark mode is on but the region is inactive."
  (interactive "P")
  (exchange-point-and-mark
   (if (and transient-mark-mode (not mark-active))
       (not arg)
     arg)))
(global-set-key [remap exchange-point-and-mark] &aposspw/exchange-point-and-mark)
We avoid turning Transient Mark mode off, but mitigate the second of the two disadvantages given above. I can t figure out why it was thought to be a good idea to make C-x C-x reactivate the mark and require C-u C-x C-x to use the action of exchanging point and mark as a means of navigation. There needs to a binding to reactivate the mark, but in roughly ten years of having Transient Mark mode turned on, I ve found that the need to reactivate the mark doesn t come up often, so the shorter and longer bindings seem the wrong way around. Not sure what I m missing here. Mitigation #2: disable Transient Mark mode, but enable it temporarily more often 
(setq transient-mark-mode nil)
(defun spw/remap-mark-command (command &optional map)
  "Remap a mark-* command to temporarily activate Transient Mark mode."
  (let* ((cmd (symbol-name command))
         (fun (intern (concat "spw/" cmd)))
         (doc (concat "Call  "
                      cmd
                      "&apos and temporarily activate Transient Mark mode.")))
    (fset fun  (lambda ()
                 ,doc
                 (interactive)
                 (call-interactively #&apos,command)
                 (activate-mark)))
    (if map
        (define-key map (vector &aposremap command) fun)
      (global-set-key (vector &aposremap command) fun))))
(dolist (command &apos(mark-word
                   mark-sexp
                   mark-paragraph
                   mark-defun
                   mark-page
                   mark-whole-buffer))
  (spw/remap-mark-command command))
(with-eval-after-load &aposorg
  (spw/remap-mark-command &aposorg-mark-element org-mode-map)
  (spw/remap-mark-command &aposorg-mark-subtree org-mode-map))
;; optional
(global-set-key "\M-=" (lambda () (interactive) (activate-mark)))
;; resettle the previous occupant
(global-set-key "\C-cw" &aposcount-words-region)
Here we remove both of the disadvantages of Transient Mark mode given above, and mitigate the main disadvantage of not activating Transient Mark mode by making it more convenient to activate it temporarily. For example, this enables using C-M-SPC C-M-SPC M-( to wrap the following two function arguments in parentheses. And you can hit M-h a few times to mark some blocks of text or code, then operate on them with commands like M-% and C-/ which behave differently when the region is active.1 Comparing these mitigations Both of these mitigations handle the second of the two disadvantages of Transient Mark mode given above. What remains, then, is
  1. under the effects of mitigation #1, how much of a barrier to using marks for navigational purposes is it to have to press C-SPC C-SPC instead of having a single binding, C-SPC, for all manual mark setting2
  2. under the effects of mitigation #2, how much of a barrier to taking advantage of commands which act differently when the region is active is it to have to temporarily enable Transient Mark mode with C-SPC C-SPC, M-= or one of the mark-* commands?
These are unknowns.3 So I m going to have to experiment, I think, to determine which mitigation to use, if either. In particular, I don t know whether it s really significant that setting a mark for navigational purposes and for region marking purposes are distinct operations under mitigation #1. My plan is to start with mitigation #2 because that has the additional advantage of allowing me to confirm or disconfirm my belief that not being able to see where the region is will only rarely get in my way.
  1. The idea of making the mark-* commands activate the mark comes from an emacs-devel post by Stefan Monnier in the archives linked above.
  2. One remaining possibility I m not considering is mitigation #1 plus binding something else to do the same as C-SPC C-SPC. I don t believe there are any easily rebindable keys which are easier to type than typing C-SPC twice. And this does not deal with the two distinct mark-setting operations problem.
  3. Another way to look at this is the question of which of setting a mark for navigational purposes and activating a mark should get C-SPC and which should get C-SPC C-SPC.

29 May 2020

Keith Packard: picolibc-string-float

Float/String Conversion in Picolibc Exact conversion between strings and floats seems like a fairly straightforward problem. There are two related problems:
  1. String to Float conversion. In this case, the goal is to construct the floating point number which most closely approximates the number represented by the string.
  2. Float to String conversion. Here, the goal is to generate the shortest string which, when fed back into the String to Float conversion code, exactly reproduces the original value.
When linked together, getting from float to string and back to float is a round trip , and an exact pair of algorithms does this for every floating point value. Solutions for both directions were published in the proceedings of the ACM SIGPLAN 1990 conference on Programming language design and implementation, with the string-to-float version written by William Clinger and the float-to-string version written by Guy Steele and Jon White. These solutions rely on very high precision integer arithmetic to get every case correct, with float-to-string requiring up to 1050 bits for the 64-bit IEEE floating point format. That's a lot of bits. Newlib Float/String Conversion The original newlib code, written in 1998 by David M. Gay, has arbitrary-precision numeric code for these functions to get exact results. However, it has the disadvantages of performing numerous memory allocations, consuming considerable space for the code, and taking a long time for conversions. The first disadvantage, using malloc during conversion, ended up causing a number of CVEs because the results of malloc were not being checked. That's bad on all platforms, but especially bad for embedded systems where reading and writing through NULL pointers may have unknown effects. Upstream newlib applied a quick fix to check the allocations and call abort. Again, on platforms with an OS, that at least provides a way to shut down the program and let the operating environment figure out what to do next. On tiny embedded systems, there may not be any way to log an error message or even restart the system. Ok, so we want to get rid of the calls to abort and have the error reported back through the API call which caused the problem. That's got two issues, one mere technical work, and another mere re-interpretation of specifications. Let's review the specification issue. The libc APIs involved here are: Input: Output: Scanf and printf are both documented to set errno to ENOMEM when they run out of memory, but none of the other functions takes that possibility into account. So we'll make some stuff up and hope it works out: Now, looking back at the technical challenge. That's a simple matter of inserting checks at each allocation, or call which may result in an allocation, and reporting failure back up the call stack, unwinding any intermediate state to avoid leaking memory. Testing Every Possible Allocation Failure There are a lot of allocation calls in the newlib code. And the call stack can get pretty deep. A simple visual inspection of the code didn't seem sufficient to me to validate the allocation checking code. So I instrumented malloc, making it count the number of allocations and fail at a specific one. Now I can count the total number of allocations done over the entire test suite run for each API involved and then run the test suite that many times, failing each allocation in turn and checking to make sure we recover correctly. By that, I mean: There were about 60000 allocations to track, so I ran the test suite that many times, which (with the added malloc tracing enabled) took about 12 hours. Bits Pushed to the Repository With the testing complete, I'm reasonably confident that the code is now working, and that these CVEs are more completely squashed. If someone is interested in back-porting the newlib fixes upstream to newlib, that would be awesome. It's not completely trivial as this part of picolibc has diverged a bit due to the elimination of the reent structure. Picolibc's Tinystdio Float/String Conversion Picolibc contains a complete replacement for stdio which was originally adopted from avr libc. That's a stdio implementation designed to run on 8-bit Atmel processors and focuses on very limited memory use and small code size. It does this while maintaining surprisingly complete support for C99 printf and scanf support. However, it also does this without any arbitrary precision arithmetic, which means it doesn't get the right answer all of the time. For most embedded systems, this is usually a good trade off -- floating point input and output are likely to be largely used for diagnostics and debugging, so mostly correct answers are probably sufficient. The original avr-libc code only supports 32-bit floats, as that's all the ABI on those processors has. I extended that to 64-, 80- and 128- bit floats to cover double and long double on x86 and RISC-V processors. Then I spent a bunch of time adjusting the code to get it to more accurately support C99 standards. Tinystdio also had strtod support, but it was missing ecvt, fcvt and gcvt. For those, picolibc was just falling back to the old newlib code, which introduced all of the memory allocation issues we've just read about. Fixing that so that tinystdio was self-contained and did ecvt, fcvt and gcvt internally required writing those functions in terms of the float-to-string primitives already provided in tinystdio to support printf. gcvt is most easily supported by just calling sprintf. Once complete, the default picolibc build, using tinystdio, no longer does any memory allocation for float/string conversions.

28 May 2020

Antoine Beaupr : Upgrading my home server uplink

For more than a few decades now (!), I've been running my own server. First it was just my old Pentium 1 squatting on university networks, but eventually grew into a real server somewhere at the dawn of the millenia. Apart from the university days, the server was mostly hosted over ADSL links, first a handful of megabits, up to the current 25 Mbps down, 6 Mbps up that the Bell Canada network seems to allow to its resellers (currently Teksavvy Internet, or TSI).

Why change? Obviously, this speed is showing its age, and especially in this age of Pandemia where everyone is on videoconferencing all the time. But it's also inconvenient when I need to upload large files on the network. I also host a variety of services on this network, and I always worry that any idiot can (rather trivially) DoS my server, so I often feel I should pack a little more punch at home (although I have no illusions about my capacity of resisting any sort of DoS attack at home of course). Also, the idea of having gigabit links at home brings back the idea of the original internet, that everyone on the internet is a "peer". "Client" and "servers" are just a technical distinction and everyone should be able to run a server.

Requirements So I'm shopping for a replacement. The requirements are:
  1. higher speed than 25/6, preferably 100mbps down, 30mbps up, or more. ideally 1gbps symmetric.
  2. static or near-static IP address: I run a DNS server with its IP in the glue records (although the latter could possibly be relaxed). ideally a /29 or more.
  3. all ports open: I run an SMTP server (incoming and outgoing) along with a webserver and other experiments. ideally, no firewall or policy should be blocking me from hosting stuff, unless there's an attack or security issue, obviously.
  4. clean IP address: the SMTP server needs to have a good reputation, so the IP address should not be in a "residential space" pool.
  5. IPv6 support: TSI offers IPv6 support, but it is buggy (I frequently have to restart the IPv6 interface on the router because the delegated block stops routing, and they haven't been able to figure out the problem). ideally, a /56.
  6. less than 100$/mth, ideally close to the current 60$/mth I pay.
(All amounts in $CAD.)

Contestants I wrote a similar message asking major ISPs in my city for those services, including business service if necessary: I have not contacted those providers:
  • Bell Canada: i have sworn, two decades ago, never to do business with that company ever again. They have a near-monopoly on almost all telcos in Canada and I want to give them as little money as possible.
  • Videotron: I know for a fact they do not allow servers on their network, and their IPv6 has been in beta for so long it has become somewhat of a joke now
I might have forgotten some, let me know if you're in the area and have a good recommendation. I'll update this post with findings as they come in. Keep in mind that I am in a major Canadian city, less than a kilometer from a major telco exchange site, so it's not like I'm in a rural community. This should just work.

TSI First answer from TSI was "we do not provide 30mbps upload on residential services", even though they seem to have that package on their website. They confirmed that they "don't have a option more than 10 mbps upload." TSI were the first to respond, within 24h.

Oricom They offer a 100/30 link for 65$ plus 25$ for a static IP. No IPv6 yet, unlikely to come soon. No services blocked, they have their own PoP within Videotron's datacenters so clients come out from their IP address space. I can confirm that the IP is fairly static from the office. Oricom were the second to respond, within 24h, but required a phone call instead of an email exchange. Responded within 6 hours after leaving a voicemail.

Ebox Ebox claims my neighborhood supports 400mbps down, but offered me a 100/30 package with 350Go bandwidth per month for 54.95$/mth or unlimited for 65$/mth. Many ports are blocked, which makes it impossible for me to use their service:
  • port 25 blocked incoming
  • port 25 filtered outgoing (only allowed to their servers)
  • port 53 blocked incoming (!)
No static IP addressing, shared dynamic space so no garantee on reputation. IPv6 only on DSL, so no high speed IPv6. Ebox took the longest to respond, about 48 hours.

Beanfield / Openface Even though they have a really interesting service (50$/mth for unlimited 1gbps), they are not in my building. I did try to contact them over chat, they told me to call, and I left a message. They responded saying they mostly offer business services for now, no residential in Montreal.

Elana Hashman: Presenter mode in LibreOffice Impress without an external display

I typically use LibreOffice Impress for my talks, much to some folks' surprise. Yes, you can make slides look okay with free software! But there's one annoying caveat that has bothered me for ages. Impress makes it nearly impossible to enter presenter mode with a single display, while also displaying slides. I have never understood this limitation, but it's existed for a minimum of seven years. I've tried all sorts of workarounds over the years, including a macro that forces LibreOffice into presenter mode, which I never was able to figure out how to reverse once I ran it... This has previously been an annoyance but never posed a big problem, because when push came to shove I could leave my house and use an external monitor or screen when presenting at meetups. But now, everything's virtual, I'm in lockdown indefinitely, and I don't have another display available at home. And about 8 hours before speaking at a meetup today, I realized I didn't have a way to share my slides while seeing my speaker notes. Uh oh. So I got this stupid idea. ...why don't I just placate LibreOffice with a FAKE display? Virtual displays with xrandr My GPU had this capability innately, it turns out, if I could just whisper the right incantations to unlock its secrets: 
ehashman@red-dot:~$ cat /usr/share/X11/xorg.conf.d/20-intel.conf 
Section "Device"
    Identifier "intelgpu0"
    Driver "intel"
    Option "VirtualHeads" "1"
EndSection
After restarting X to allow this newly created config to take effect, I now could see two new virtual displays available for use: 
ehashman@red-dot:~$ xrandr
Screen 0: minimum 8 x 8, current 3840 x 1080, maximum 32767 x 32767
eDP1 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 310mm x 170mm
   1920x1080     60.01*+  59.93  
   ...
   640x360       59.84    59.32    60.00  
DP1 disconnected (normal left inverted right x axis y axis)
DP2 disconnected (normal left inverted right x axis y axis)
HDMI1 disconnected (normal left inverted right x axis y axis)
HDMI2 disconnected (normal left inverted right x axis y axis)
VIRTUAL1 disconnected (normal left inverted right x axis y axis)
VIRTUAL2 disconnected (normal left inverted right x axis y axis)
Nice. Now, to actually use it: 
ehashman@red-dot:~$ xrandr --addmode VIRTUAL1 1920x1080
ehashman@red-dot:~$ xrandr --output VIRTUAL1 --mode 1920x1080 --right-of eDP1
And indeed, after running these commands, I found myself with a virtual display, very happy to black hole all my windows, available to the imaginary right of my laptop screen. This allowed me to mash that "Present" button in LibreOffice and get my presenter notes on my laptop display, while putting my actual slides in a virtual time-out that I could still screenshare! Wouldn't it be nice if LibreOffice just fixed the actual bug? Well, actually... I must forgive myself for my stage panic. The talk ended up going great, and the immediate problem was solved. But it turns out this bug has been addressed upstream! It's just... not well-documented. A couple years ago, there was a forum post on ask.libreoffice.org that featured this exact question, and a solution was provided!
Yes, use Open Expert Configuration via Tools > Options > LibreOffice > Advanced. Search for StartAlways. You should get a node org.openoffice.Office.PresenterScreen with line Presenter. Double-click that line to toggle the boolean value to true.
I tested this out locally and... yeah that works. But it turns out the bug from 2013 had not been updated with this solution until just a few months ago. There are very limited search results for this configuration property. I wish this was much better documented. But so it goes with free software; here's a hack and a real solution as we all try to improve things :)

26 May 2020

Russell Coker: Cruises and Covid19

Problems With Cruises GQ has an insightful and detailed article about Covid19 and the Diamond Princess [1], I recommend reading it. FastCompany has a brief article about bookings for cruises in August [2]. There have been many negative comments about this online. The first thing to note is that the cancellation policies on those cruises are more lenient than usual and the prices are lower. So it s not unreasonable for someone to put down a deposit on a half price holiday in the hope that Covid19 goes away (as so many prominent people have been saying it will) in the knowledge that they will get it refunded if things don t work out. Of course if the cruise line goes bankrupt then no-one will get a refund, but I think people are expecting that won t happen. The GQ article highlights some serious problems with the way cruise ships operate. They have staff crammed in to small cabins and the working areas allow transmission of disease. These problems can be alleviated, they could allocate more space to staff quarters and have more capable air conditioning systems to put in more fresh air. During the life of a cruise ship significant changes are often made, replacing engines with newer more efficient models, changing the size of various rooms for entertainment, installing new waterslides, and many other changes are routinely made. Changing the staff only areas to have better ventilation and more separate space (maybe capsule-hotel style cabins with fresh air piped in) would not be a difficult change. It would take some money and some dry-dock time which would be a significant expense for cruise companies. Cruises Are Great People like social environments, they want to have situations where there are as many people as possible without it becoming impossible to move. Cruise ships are carefully designed for the flow of passengers. Both the layout of the ship and the schedule of events are carefully planned to avoid excessive crowds. In terms of meeting the requirement of having as many people as possible in a small area without being unable to move cruise ships are probably ideal. Because there is a large number of people in a restricted space there are economies of scale on a cruise ship that aren t available anywhere else. For example the main items on the menu are made in a production line process, this can only be done when you have hundreds of people sitting down to order at the same time. The same applies to all forms of entertainment on board, they plan the events based on statistical knowledge of what people want to attend. This makes it more economical to run than land based entertainment where people can decide to go elsewhere. On a ship a certain portion of the passengers will see whatever show is presented each night, regardless of whether it s singing, dancing, or magic. One major advantage of cruises is that they are all inclusive. If you are on a regular holiday would you pay to see a singing or dancing show? Probably not, but if it s included then you might as well do it and it will be pretty good. This benefit is really appreciated by people taking kids on holidays, if kids do things like refuse to attend a performance that you were going to see or reject food once it s served then it won t cost any extra. People Who Criticise Cruises For the people who sneer at cruises, do you like going to bars? Do you like going to restaurants? Live music shows? Visiting foreign beaches? A cruise gets you all that and more for a discount price. If Groupon had a deal that gave you a cheap hotel stay with all meals included, free non-alcoholic drinks at bars, day long entertainment for kids at the kids clubs, and two live performances every evening how many of the people who reject cruises would buy it? A typical cruise is just like a Groupon deal for non-stop entertainment from 8AM to 11PM. Will Cruises Restart? The entertainment options that cruises offer are greatly desired by many people. Most cruises are aimed at budget travellers, the price is cheaper than a hotel in a major city. Such cruises greatly depend on economies of scale, if they can t get the ships filled then they would need to raise prices (thus decreasing demand) to try to make a profit. I think that some older cruise ships will be scrapped in the near future and some of the newer ships will be sold to cruise lines that cater to cheap travel (IE P&O may scrap some ships and some of the older Princess ships may be transferred to them). Overall I predict a decrease in the number of middle-class cruise ships. For the expensive cruises (where the cheapest cabins cost over $1000US per person per night) I don t expect any real changes, maybe they will have fewer passengers and higher prices to allow more social distancing or something. I am certain that cruises will start again, but it s too early to predict when. Going on a cruise is about as safe as going to a concert or a major sporting event. No-one is predicting that sporting stadiums will be closed forever or live concerts will be cancelled forever, so really no-one should expect that cruises will be cancelled forever. Whether companies that own ships or stadiums go bankrupt in the mean time is yet to be determined. One thing that s been happening for years is themed cruises. A group can book out an entire ship or part of a ship for a themed cruise. I expect this to become much more popular when cruises start again as it will make it easier to fill ships. In the past it seems that cruise lines let companies book their ships for events but didn t take much of an active role in the process. I think that the management of cruise lines will look to aggressively market themed cruises to anyone who might help, for starters they could reach out to every 80s and 90s pop group those fans are all old enough to be interested in themed cruises and the musicians won t be asking for too much money. Conclusion Humans are social creatures. People want to attend events with many other people. Covid 19 won t be the last pandemic, and it may not even be eradicated in the near future. The possibility of having a society where no-one leaves home unless they are in a hazmat suit has been explored in science fiction, but I don t think that s a plausible scenario for the near future and I don t think that it s something that will be caused by Covid 19.
Related posts:
  1. Cruises It seems that in theory cruises can make for quite...
  2. A Computer Conference on a Cruise Ship After LCA [1] there was a discussion about possible locations...
  3. My First Cruise A few weeks ago I went on my first cruise,...

Russ Allbery: Review: The Ten Thousand Doors of January

Review: The Ten Thousand Doors of January, by Alix E. Harrow
Publisher: Redhook
Copyright: September 2019
ISBN: 0-316-42198-7
Format: Kindle
Pages: 373
In 1901, at the age of seven, January found a Door. It was barely more than a frame in a ruined house in a field in Kentucky, but she wrote a story about opening it, and then did.
Once there was a brave and temeraryous (sp?) girl who found a Door. It was a magic Door that's why it has a capital D. She opened the Door.
The Door led to a bluff over the sea and above a city, a place very far from Kentucky, and she almost stayed, but she came back through the Door when her guardian, Mr. Locke, called. The adventure cost her a diary, several lectures, days of being locked in her room, and the remnants of her strained relationship with her father. When she went back, the frame of the Door was burned to the ground. That was the end of Doors for January for some time, and the continuation of a difficult childhood. She was cared for by her father's employer as a sort of exotic pet, dutifully attempting to obey, grateful for Mr. Locke's protection, and convinced that he was occasionally sneaking her presents through a box in the Pharaoh Room out of some hidden kindness. Her father appeared rarely, said little, and refused to take her with him. Three things helped: the grocery boy who smuggled her stories, an intimidating black woman sent by her father to replace her nurse, and her dog.
Once upon a time there was a good girl who met a bad dog, and they became the very best of friends. She and her dog were inseparable from that day forward.
I will give you a minor spoiler that I would have preferred to have had, since it would have saved me some unwarranted worry and some mental yelling at the author: The above story strains but holds. January's adventure truly starts the day before her seventeenth birthday, when she finds a book titled The Ten Thousand Doors in the box in the Pharaoh Room. As you may have guessed from the title, The Ten Thousand Doors of January is a portal fantasy, but it's the sort of portal fantasy that is more concerned with the portal itself than the world on the other side of it. (Hello to all of you out there who, like me, have vivid memories of the Wood between the Worlds.) It's a book about traveling and restlessness and the possibility of escape, about the ability to return home again, and about the sort of people who want to close those doors because the possibility of change created by people moving around freely threatens the world they have carefully constructed. Structurally, the central part of the book is told by interleaving chapters of January's tale with chapters from The Ten Thousand Doors. That book within a book starts with the framing of a scholarly treatment but quickly becomes a biography of a woman: Adelaide Lee Larson, a half-wild farm girl who met her true love at the threshold of a Door and then spent much of her life looking for him. I am not a very observant reader for plot details, particularly for books that I'm enjoying. I read books primarily for the emotional beats and the story structure, and often miss rather obvious story clues. (I'm hopeless at guessing the outcomes of mysteries.) Therefore, when I say that there are many things January is unaware of that are obvious to the reader, that's saying a lot. Even more clues were apparent when I skimmed the first chapter again, and a more observant reader would probably have seen them on the first read. Right down to Mr. Locke's name, Harrow is not very subtle about the moral shape of this world. That can make the early chapters of the book frustrating. January is being emotionally (and later physically) abused by the people who have power in her life, but she's very deeply trapped by false loyalty and lack of external context. Winning free of that is much of the story of the book, and at times it has the unpleasantness of watching someone make excuses for her abuser. At other times it has the unpleasantness of watching someone be abused. But this is the place where I thought the nested story structure worked marvelously. January escapes into the story of The Ten Thousand Doors at the worst moments of her life, and the reader escapes with her. Harrow uses the desire to switch scenes back to the more adventurous and positive story to construct and reinforce the emotional structure of the book. For me, it worked extremely well. It helps that the ending is glorious. The payoff is worth all the discomfort and tension-building in the first half of the book. Both The Ten Thousand Doors and the surrounding narrative reach deeply satisfying conclusions, ones that are entangled but separate in just the ways that they need to be. January's abilities, actions, and decisions at the end of the book were just the outcome that I needed but didn't entirely guess in advance. I could barely put down the last quarter of this story and loved every moment of the conclusion. This is the sort of book that can be hard to describe in a review because its merits don't rest on an original twist or easily-summarized idea. The elements here are all elements found in other books: portal fantasy, the importance of story-telling, coming of age, found family, irrepressible and indomitable characters, and the battle of the primal freedom of travel and discovery and belief against the structural forces that keep rulers in place. The merits of this book are in the small details: the way that January's stories are sparse and rare and sometimes breathtaking, the handling of tattoos, the construction of other worlds with a few deft strokes, and the way Harrow embraces the emotional divergence between January's life and Adelaide's to help the reader synchronize the emotional structure of their reading experience with January's.
She writes a door of blood and silver. The door opens just for her.
The Ten Thousand Doors of January is up against a very strong slate for both the Nebula and the Hugo this year, and I suspect it may be edged out by other books, although I wouldn't be unhappy if it won. (It probably has a better shot at the Nebula than the Hugo.) But I will be stunned if Harrow doesn't walk away with the Mythopoeic Award. This seems like exactly the type of book that award was created for. This is an excellent book, one of the best I've read so far this year. Highly recommended. Rating: 9 out of 10

Norbert Preining: Multi-device and RAID1 with btrfs

I have been using btrfs, a modern modern copy on write filesystem for Linux, since many years now. But only recently I realized how amateurish my usage has been. Over the last day I switched to multiple devices and threw in a RAID1 level at the same time.
For the last years, I have been using btrfs in a completely naive way, simply creating new filesystems, mounting them, moving data over, linking the directories into my home dir, etc etc. It all became a huge mess over time. I have heard of multi-device support , but always thought that this is for the big players in the data centers not realizing that it works trivially on your home system, too. Thanks to an article by Mark McBride I learned how to better use it! Btrfs has an impressive list of features, and is often compared to (Open)ZFS (btw, they domain openzfs.org has a botched SSL certificate .. umpf, my trust disappears even more) due to the high level of data security. I have been playing around with the idea to use ZFS for quite some time, but first of all it requires compiling extra modules all the time, because ZFS cannot be included in the kernel source. And much more, I realized that ZFS is simply too inflexible with respect to disks of different sizes in a storage pool. Btrfs on the other hand allows adding and removing devices to the filesystem on a running system. I just added a 2TB disk to my rig, and called: 
btrfs device add /dev/sdh1 /
and with that alone, my root filesystem grew immediately. At the end I have consolidated data from 4 extra SSDs into this new filesystem spanning multiple disks, and got rid of all the links and loops. For good measure, and since I had enough space left, I also switched to RAID1 for this filesystem. This again, surprisingly, works on a running system! 
btrfs balance start -dconvert=raid1 -mconvert=raid1 /
Here, both data and metadata are mirrored on the devices. With 6TB of total disk space, the balancing operation took quite some time, about 6h in my case, but finished without a hiccup. After all that, the filesystem now looks like this: 
$ sudo btrfs fi show /
Label: none  uuid: XXXXXX
	Total devices 5 FS bytes used 2.19TiB
	devid    1 size 899.01GiB used 490.03GiB path /dev/sdb3
	devid    2 size 489.05GiB used 207.00GiB path /dev/sdd1
	devid    3 size 1.82TiB used 1.54TiB path /dev/sde1
	devid    4 size 931.51GiB used 649.00GiB path /dev/sdf1
	devid    5 size 1.82TiB used 1.54TiB path /dev/sdc1
and using btrfs fi usage / I can get detailed information about the device usage and status. Stumbling blocks You wouldn t expect such a deep rebuilding of the intestines of a system to go without a few bumps, and indeed, there are a few: First of all, update-grub is broken when device names are used. If you have GRUB_DISABLE_LINUX_UUID=true, so that actual device nodes are used in grub.cfg, the generated entries are broken because they list all the devices. This comes from the fact that grub-mkconfig uses grub-probe --target=device / to determine the root device, and this returns in our case: 
# grub-probe --target=device /
/dev/sdb3
/dev/sdd1
/dev/sde1
/dev/sdf1
/dev/sdc1
and thus the grub config file contains entries like: 
...
menuentry 'Debian GNU/Linux ...' ...  
  ...
  linux	/boot/vmlinuz-5.7.0-rc7 root=/dev/sdb3
/dev/sdd1
/dev/sde1
/dev/sdf1
/dev/sdc1 ro <other options>
This is of course an invalid entry, but fortunately grub still boots, but ignores the rest of the command line options. So I decided to turn back to using UUID for the root entry, which should be better supported. But alas, what happened, I couldn t even boot anymore. Grub gave me very cryptic messages like cannot find UUID device and dropping you into the grub rescue shell, then having the grub rescue shell being unable to read any filesystem at all (not even FAT or ext2!). The most cryptic one was grub header bytenr is not equal node addr, where even Google gave up on it. At the end I booted into a rescue image (you always have something like SystemRescueCD on an USB stick next to you during these operations, right?), mounted the filesystem manually, and reinstalled grub, which fixed the problem, and now the grub config file contains only the UUID for root. I don t blame btrfs for that, this is more like we are, after sooo many years, we still don t have a good boot system All in all, a very smooth transition, and at least for some time I don t have to worry about which partition has still some space left. Thanks btrfs and Open Source!

25 May 2020

Russ Allbery: Review: The Last Emperox

Review: The Last Emperox, by John Scalzi
Series: Interdependency #3
Publisher: Tor
Copyright: April 2020
ISBN: 0-7653-8917-7
Format: Kindle
Pages: 318
This is the conclusion of the Interdependency trilogy, which is a single story told in three books. Start with The Collapsing Empire. You don't want to read this series out of order. All the pieces and players are in place, the causes and timeline of the collapse of the empire she is accidentally ruling are now clear, and Cardenia Wu-Patrick knows who her friends and enemies are. What she doesn't know is what she can do about it. Her enemies, unfettered Cardenia's ethics or desire to save the general population, have the advantage of clearer and more achievable goals. If they survive and, almost as important, remain in power, who cares what happens to everyone else? As with The Consuming Fire, the politics may feel a bit too on-the-nose for current events, this time for the way that some powerful people are handling (or not handling) the current pandemic. Also as with The Consuming Fire, Scalzi's fast-moving story, likable characters, banter, and occasional humorous descriptions prevent those similarities from feeling heavy or didactic. This is political wish fulfillment to be sure, but it doesn't try to justify itself or linger too much on its improbabilities. It's a good story about entertaining people trying (mostly) to save the world with a combination of science and political maneuvering. I picked up The Last Emperox as a palate cleanser after reading Gideon the Ninth, and it provided exactly what I was looking for. That gave me an opportunity to think about what Scalzi does in his writing, why his latest novel was one of my first thoughts for a palate cleanser, and why I react to his writing the way that I do. Scalzi isn't a writer about whom I have strong opinions. In my review of The Collapsing Empire, I compared his writing to the famous description of Asimov as the "default voice" of science fiction, but that's not quite right. He has a distinct and easily-recognizable style, heavy on banter and light-hearted description. But for me his novels are pleasant, reliable entertainment that I forget shortly after reading them. They don't linger or stand out, even though I enjoy them while I'm reading them. That's my reaction. Others clearly do not have that reaction, fully engage with his books, and remember them vividly. That indicates to me that there's something his writing is doing that leaves substantial room for difference of personal taste and personal reaction to the story, and the sharp contrast between The Last Emperox and Gideon the Ninth helped me put my finger on part of it. I don't feel like Scalzi's books try to tell me how to feel about the story. There's a moment in The Last Emperox where Cardenia breaks down crying over an incredibly difficult decision that she's made, one that the readers don't find out about until later. In another book, there would be considerably more emotional build-up to that moment, or at least some deep analysis of it later once the decision is revealed. In this book, it's only a handful of paragraphs and then a few pages of processing later, primarily in dialogue, and less focused on the emotions of the characters than on the forward-looking decisions they've made to deal with those emotions. The emotion itself is subtext. Many other authors would try to pull the reader into those moments and make them feel what the characters are feeling. Scalzi just relates them, and leaves the reader free to feel what they choose to feel. I don't think this is a flaw (or a merit) in Scalzi's writing; it's just a difference, and exactly the difference that made me reach for this book as an emotional break after a book that got its emotions all over the place. Calling Scalzi's writing emotionally relaxing isn't quite right, but it gives me space to choose to be emotionally relaxed if I want to be. I can pick the level of my engagement. If I want to care about these characters and agonize over their decisions, there's enough information here to mull over and use to recreate their emotional states. If I just want to read a story about some interesting people and not care too much about their hopes and dreams, I can choose to do that instead, and the book won't fight me. That approach lets me sidle up on the things that I care about and think about them at my leisure, or leave them be. This approach makes Scalzi's books less intense than other novels for me. This is where personal preference comes in. I read books in large part to engage emotionally with the characters, and I therefore appreciate books that do a lot of that work for me. Scalzi makes me do the work myself, and the result is not as effective for me, or as memorable. I think this may be part of what I and others are picking up on when we say that Scalzi's writing is reminiscent of classic SF from decades earlier. It used to be common for SF to not show any emotional vulnerability in the main characters, and to instead focus on the action plot and the heroics and martial virtues. This is not what Scalzi is doing, to be clear; he has a much better grasp of character and dialogue than most classic SF, adds considerable light-hearted humor, and leaves clear clues and hooks for a wide range of human emotions in the story. But one can read Scalzi in that tone if one wants to, since the emotional hooks do not grab hard at the reader and dig in. By comparison, you cannot read Gideon the Ninth without grappling with the emotions of the characters. The book will not let you. I think this is part of why Scalzi is so consistent for me. If you do not care deeply about Gideon Nav, you will not get along with Gideon the Ninth, and not everyone will. But several main characters in The Last Emperox (Mance and to some extent Cardenia) did little or nothing for me emotionally, and it didn't matter. I liked Kiva and enjoyed watching her strategically smash her way through social conventions, but it was easy to watch her from a distance and not get too engrossed in her life or her thoughts. The plot trundled along satisfyingly, regardless. That lack of emotional involvement precludes, for me, a book becoming the sort of work that I will rave about and try to press into other people's hands, but it also makes it comfortable and gentle and relaxing in a way that a more emotionally fraught book could not be. This is a long-winded way to say that this was a satisfying conclusion to a space opera trilogy that I enjoyed reading, will recommend mildly to others, and am already forgetting the details of. If you liked the first two books, this is an appropriate and fun conclusion with a few new twists and a satisfying amount of swearing (mostly, although not entirely, from Kiva). There are a few neat (albeit not horribly original) bits of world-building, a nice nod to and subversion of Asimov, a fair bit of political competency wish fulfillment (which I didn't find particularly believable but also didn't mind being unbelievable), and one enjoyable "oh no she didn't" moment. If you like the thing that Scalzi is doing, you will enjoy this book. Rating: 8 out of 10

24 May 2020

Fran ois Marier: Printing hard-to-print PDFs on Linux

I recently found a few PDFs which I was unable to print due to those files causing insufficient printer memory errors: I found a detailed explanation of what might be causing this which pointed the finger at transparent images, a PDF 1.4 feature which apparently requires a more recent version of PostScript than what my printer supports. Using Okular's Force rasterization option (accessible via the print dialog) does work by essentially rendering everything ahead of time and outputing a big image to be sent to the printer. The quality is not very good however.

Converting a PDF to DjVu The best solution I found makes use of a different file format: .djvu Such files are not PDFs, but can still be opened in Evince and Okular, as well as in the dedicated DjVuLibre application. As an example, I was unable to print page 11 of this paper. Using pdfinfo, I found that it is in PDF 1.5 format and so the transparency effects could be the cause of the out-of-memory printer error. Here's how I converted it to a high-quality DjVu file I could print without problems using Evince: 
pdf2djvu -d 1200 2002.04049.pdf > 2002.04049-1200dpi.djvu

Converting a PDF to PDF 1.3 I also tried the DjVu trick on a different unprintable PDF, but it failed to print, even after lowering the resolution to 600dpi: 
pdf2djvu -d 600 dow-faq_v1.1.pdf > dow-faq_v1.1-600dpi.djvu
In this case, I used a different technique and simply converted the PDF to version 1.3 (from version 1.6 according to pdfinfo): 
ps2pdf13 -r1200x1200 dow-faq_v1.1.pdf dow-faq_v1.1-1200dpi.pdf
This eliminates the problematic transparency and rasterizes the elements that version 1.3 doesn't support.

23 May 2020

Rapha&#235;l Hertzog: Freexian s report about Debian Long Term Support, April 2020

A Debian LTS logo Like each month, here comes a report about the work of paid contributors to Debian LTS. Individual reports In April, 284.5 work hours have been dispatched among 14 paid contributors. Their reports are available: Evolution of the situation In April we dispatched more hours than ever and another was new too, we had our first (virtual) contributors meeting on IRC! Logs and minutes are available and we plan to continue doing IRC meetings every other month.
Sadly one contributor decided to go inactive in April, Hugo Lefeuvre.
Finally, we like to remind you, that the end of Jessie LTS is coming in less than two months!
In case you missed it (or missed to act), please read this post about keeping Debian 8 Jessie alive for longer than 5 years. If you expect to have Debian 8 servers/devices running after June 30th 2020, and would like to have security updates for them, please get in touch with Freexian. The security tracker currently lists 4 packages with a known CVE and the dla-needed.txt file has 25 packages needing an update. Thanks to our sponsors New sponsors are in bold.

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22 May 2020

Steve Kemp: Updated my linux-security-modules for the Linux kernel

Almost three years ago I wrote my first linux-security-module, inspired by a comment I read on LWN I did a little more learning/experimentation and actually produced a somewhat useful LSM, which allows you to restrict command-execution via the use of a user-space helper: Because the detection is done in userspace writing your own custom rules is both safe and easy. No need to touch the kernel any further! Yesterday I rebased all the modules so that they work against the latest stable kernel 5.4.22 in #7.
The last time I'd touched them they were built against 5.1, which was itself a big jump forwards from the 4.16.7 version I'd initially used.
Finally I updated the can-exec module to make it gated, which means you can turn it on, but not turn it off without a reboot. That was an obvious omission from the initial implementation #11. Anyway updated code is available here: I'd kinda like to write more similar things, but I lack inspiration.

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