Strengths, weaknesses, opportunities, and threats facing the GNU Autotools

I’ve been a contributor to GNU projects for many years, notably both GCC and GNU libc, and recently I led the effort to make the first release of Autoconf since 2012 (release announcement for Autoconf 2.70). For background and context, see the LWN article my colleague Sumana Harihareswara of Changeset Consulting wrote.

Autoconf not having made a release in eight years is a symptom of a deeper problem. Many GNU projects, including all of the other components of the Autotools (Automake, Libtool, Gnulib, etc.) and the software they depend upon (GNU M4, GNU Make, etc.) have seen a steady decline in both contributor enthusiasm and user base over the past decade. I include myself in the group of declining enthusiasts; I would not have done the work leading up to the Autoconf 2.70 release if I had not been paid to do it. (I would like to say thank you to the project funders: Bloomberg, Keith Bostic, and the GNU Toolchain Fund of the FSF.)

The Autotools are in particularly bad shape due to the decline in contributor enthusiasm. Preparation for the Autoconf 2.70 release took almost twice as long as anticipated; I made five beta releases between July and December 2020, and merged 157 patches, most of them bugfixes. On more than one occasion I was asked why I was going to the trouble—isn’t Autoconf (and the rest of the tools by implication) thoroughly obsolete? Why doesn’t everyone switch to something newer, like CMake or Meson? (See the comments on Sumana’s LWN article for examples.)

I personally don’t think that the Autotools are obsolete, or even all that much more difficult to work with than some of the alternatives, but it is a fair question. Should development of the Autotools continue? If they are to continue, we need to find people who have the time and the inclination (and perhaps also the funding) to maintain them steadily, rather than in six-month release sprints every eight years. We also need a proper roadmap for where further development should take these projects. As a starting point for the conversation about whether the projects should continue, and what the roadmap should be, I was inspired by Sumana’s book in progress on open source project management (sample chapters are available from her website) to write up a strengths, weaknesses, opportunities, and threats analysis of Autotools.

This inventory can help us figure out how to build on new opportunities, using the Autotools’ substantial strengths, and where to invest to guard against threats and shore up current weaknesses.

Followup discussion should go to the Autoconf mailing list.


Open beta for ICLab TagTeam

I’m pleased to announce the open beta test of ICLab’s clearinghouse for data about censored websites. This site will aggregate manual and automated test reports, facilitate more efficient use of automated test resources, and help policy analysts draw conclusions about what gets censored in particular countries.

[EDIT 19 Jan 2021: The clearinghouse had to be taken down almost immediately because no one had time to maintain it. Someday the project it is part of may be continued. Read on for details on what we had and what we aspired to.]


A simple ritual for laying to rest domestic ghosts

In honor of the feast of All Souls, I thought I might put on a costume, as it were, and write a blog post as if I were an old English cunning man and you, my readers, came to me for advice on supernatural problems, rather than computational ones.

So your house is haunted. You don’t know who the ghosts were in life, and you’re maybe a bit scared to find out, but you would like to gently encourage them to let go of their troubles and move on. I have for you a simple ritual involving a little of the old rune-magic.


Call for Volunteers: Active Geolocation

For the past few months I’ve been working on a research study of active geolocation algorithms. These attempt to determine where in the world a computer is, by measuring how long it takes network messages from that computer to reach other computers in known locations.

In order to test some of these algorithms thoroughly, I need volunteers who are willing to run my measurement software on their computers, and tell me where they are. I’m especially interested in data reported from computers that are not in Europe nor North America, but data from anywhere is useful. Currently, running the software takes a fair bit of technical skill—if you’re not comfortable with the Unix command line, please wait for the friendlier web-based version which is in development.

If you’re interested, please go to for further instructions.

(For legal reasons, you must be at least 18 years old to volunteer.)

(Reproduction and dissemination of this call for volunteers is encouraged.)

Using GPG2 with a read-only .gnupg directory

Another bulletin funded by the I Just Blew An Entire Morning On This Foundation:

Suppose you want to encrypt and sign files using gpg, but without giving it ownership or write access to its own keystore. For instance, this might be necessary if the gpg process is going to be run from a low-privilege CGI user and you don’t have root privileges on the webserver. This is relatively straightforward with the classic version 1, although there’s an error message that’s harmless but impossible to suppress, but version 2 made some architectural changes that make it harder, and does not document the necessary tricks. Below the fold, how you do it.


2016 Hugo Award nominations

Let’s talk about something more fun, shall we? These were my nominations for the 2016 Hugo Awards. The final ballot will be announced on April 26. Hugo nominations, unlike final ballots, are not ranked. I’d be happy to see any of these things win their categories.

I read a lot of good stuff at novel-length this year, but not enough shorter fiction to fill all five nomination slots per category. Something to work harder on next year, I suppose. (It didn’t help that I spent most of January and February in paper crunch mode.) I don’t even try to nominate outside the fiction categories.


Do not do business with Northwest Talent Search

A depressing number of computer industry recruiters cannot be bothered to read the very first paragraph of the contact information page of this very website, or else they think they are ~special snowflakes~ and it does not apply to them. For reference, this paragraph reads


I get unwanted solicitations about once a month, and I reply with a polite but acerbic note about how they should’ve noticed the paragraph in ALL CAPS that says don’t contact me, and usually that’s the end of it. Not this time.


Bootstrapping trust in compilers

The other week, an acquaintance of mine was kvetching on Twitter about how the Rust compiler is written in Rust, and so to get started with the language you have to download a binary, and there’s no way to validate it—you could use the binary plus the matching compiler source to recreate the binary, but that doesn’t prove anything, and also if the compiler were really out to get you, you would be screwed the moment you ran the binary.

This is not a new problem, nor is it a Rust-specific problem. I recall having essentially the same issue back in 2000, give or take, with GNAT, the Ada front-end for GCC. It is written in Ada, and (at the time, anyway) not just any Ada compiler would do, you had to have a roughly contemporaneous version of … GNAT. It was especially infuriating compared to the rest of GCC, which (again, at the time) bent over backward to be buildable with any C compiler you could get your hands on, even a traditional one that didn’t support all of the 1989 language standard. But even that is problematic for someone who would rather not trust any machine code they didn’t verify themselves.

One way around the headache is diverse recompilation, in which you compile the same compiler with two different compilers, then recompile it with itself-as-produced-by-each, and compare the results. But this requires you to have two different compilers in the first place. As of this writing there is only one Rust compiler. There aren’t that many complete implementations of C++ out there, either, and you need one of those to build LLVM (which Rust depends on). I think you could devise a compiler virus that could propagate itself via both LLVM and GCC, for instance.

What’s needed, I think, is an independent root of correctness. A software environment built from scratch to be verifiable, maybe even provably correct, and geared specifically to host independent implementations of compilers for popular languages. They need not be terribly good at optimizing, because the only thing you’d ever use them for is to be one side of a diversely-recompiled bootstrap sequence. It has to be a complete and isolated environment, though, because it wouldn’t be impossible to propagate a compiler virus through the operating system kernel, which can see every block of I/O, after all.

And it seems to me that this environment naturally divides into four pieces. First, a tiny virtual machine. I’m thinking a FORTH interpreter, which is small enough that one programmer can code it by hand in assembly language, and having done that, another programmer can audit it by hand. You need multiple implementations of this, so you can check them against each other to guard against malicious lower layers—it could run on the bare metal, maybe, but the bare metal has an awful lot of clever embedded in it these days. But hopefully this is the only thing you need to implement more than once.

Second, you use the FORTH interpreter as the substratum for a more powerful language. If there’s a language in which each program is its own proof of correctness, that would be the obvious choice, but my mental allergy to arrow languages has put me off following that branch of PL research. Lisp is generally a good language to write compilers in, so a small dialect of that would be another obvious choice. (Maybe leave out the call/cc.)

Third, you write compilers in the more powerful language, with both the FORTH interpreter and more conventional execution environments as code-generation targets. These compilers can then be used to compile other stuff to run in the environment, and conversely, you can build arbitrary code within the environment and export it to your more conventional OS.

The fourth and final piece is a way of getting data in and out of the environment. I imagine it as strictly batch-oriented, not interactive at all, simply because that cuts out a huge chunk of complexity from the FORTH interpreter; similarly it does not have any business talking to the network, nor having any notion of time, maybe not even concurrency—most compile jobs are embarrassingly parallel, but again, huge chunk of complexity. What feels not-crazy to me is some sort of trivial file system: ar archive level of trivial, all files write-once, imposed on a linear array of disk blocks.

It is probably also necessary to reinvent Make, or at least some sort of batch job control language.

Operating system selection for $PROJECT, mid-2015

Presented without context, for amusement purposes only, a page from my notes:

FreeBSD NetBSD Linux
Per-process default route Poorly documented,
possibly incomplete
Probably not Poorly documented,
Can compile PhantomJS Probably Probably Yes
Jails Yes No Not really
Xen paravirtual guest Incomplete Yes Yes
System call tracing truss None? strace
pipe2 Yes Yes Yes
closefrom Yes Yes No
sysctl Yes Yes No
getauxval No No Yes
signalfd No No Yes
execvpe No Yes Yes
Reference documentation Acceptable (YMMV1) Acceptable (YMMV) Major gaps
Tutorial documentation Terrible Terrible Terrible
Package management Broken as designed Broken as designed Good
System maintenance automation I can’t find any I can’t find any Acceptable
QA reputation Excellent Good Good
Security reputation Good Good Debatable
Development community Unknown to me Unknown to me Full of assholes

1 It makes sense to me, but then, I taught myself Unix system programming and administration by reading the SunOS 4 manpages.

Google Voice Search and the Appearance of Trustworthiness

Last week there were several bug reports [1] [2] [3] about how Chrome (the web browser), even in its fully-open-source Chromium incarnation, downloads a closed-source, binary extension from Google’s servers and installs it, without telling you it has done this, and moreover this extension appears to listen to your computer’s microphone all the time, again without telling you about it. This got picked up by the trade press [4] [5] [6] and we rapidly had a full-on Internet panic going.

If you dig into the bug reports and/or the open source part of the code involved, which I have done, it turns out that what Chrome is doing is not nearly as bad as it looks. It does download a closed-source binary extension from Google, install it, and hide it from you in the list of installed extensions (technically there are two hidden extensions involved, only one of which is closed-source, but that’s only a detail of how it’s all put together). However, it does not activate this extension unless you turn on the voice search checkbox in the settings panel, and this checkbox has always (as far as I can tell) been off by default. The extension is labeled, accurately, as having the ability to listen to your computer’s microphone all the time, but of course it does not get to do this until it is activated.

As best anyone can tell without access to the source, what the closed-source extension actually does when it’s activated is monitor your microphone for the code phrase OK Google. When it detects this phrase it transmits the next few words spoken to Google’s servers, which convert it to text and conduct a search for the phrase. This is exactly how one would expect a voice search feature to behave. In particular, a voice-activated feature intrinsically has to listen to sound all the time, otherwise how could it know that you have spoken the magic words? And it makes sense to do the magic word detection with code running on the local computer, strictly as a matter of efficiency. There is even a non-bogus business reason why the detector is closed source; speech recognition is still in the land where tiny improvements lead to measurable competitive advantage.

So: this feature is not actually a massive privacy violation. However, Google could and should have put more care into making this not appear to be a massive privacy violation. They wouldn’t have had mud thrown at them by the trade press about it, and the general public wouldn’t have had to worry about it. Everyone wins. I will now dissect exactly what was done wrong and how it could have been done better.

It was a diagnostic report, intended for use by developers of the feature, that gave people the impression the extension was listening to the microphone all the time. Below is a screen shot of this diagnostic report (click for full width). You can see it on your own copy of Chrome by typing chrome://voicesearch into the URL bar; details will probably differ a little (especially if you’re not using a Mac).

Screen shot of Google Voice Search diagnostic report, taken on Chrome 43 running on MacOS X. The most important lines of text are 'Microphone: Yes', 'Audio Capture Allowed: Yes', 'Hotword Search Enabled: No', and 'Extension State: ENABLED.
Screen shot of Google Voice Search diagnostic report, taken on Chrome 43 running on MacOS X.

Google’s first mistake was not having anyone check this over for what it sounds like it means to someone who isn’t familiar with the code. It is very well known that when faced with a display like this, people who aren’t familiar with the code will pick out whatever bits they think they understand and ignore everything else, even if that means they completely misunderstand it. [7] In this case, people see Microphone: Yes and Audio Capture Allowed: Yes and maybe also Extension State: ENABLED and assume that this means the extension is actively listening right now. (What the developers know it means is this computer has a microphone, the extension could listen to it if it had been activated, and it’s connected itself to the checkbox in the preferences so it can be activated. And it’s hard for them to realize that anyone could think it would mean something else.)

They didn’t have anyone check it because they thought, well, who’s going to look at this who isn’t a developer? Thing is, it only takes one person to look at it, decide it looks hinky, mention it online, and now you have a media circus on your hands. Obscurity is no excuse for not doing a UX review.

Now, mistake number two becomes evident when you consider what this screen ought to say in order not to scare people who haven’t turned the feature on (and maybe this is the first they’ve heard of it even): something like

Voice Search is inactive.

(A couple of sentences about what Voice Search is and why you might want it.) To activate Voice Search, go to the preferences screen and check the box.

It would also be okay to have a duplicate checkbox right there on this screen, and to have all the same debugging information show up after you check the box. But wait—how do developers diagnose problems with downloading the extension, which happens before the box has been checked? And that’s mistake number two. The extension should not be downloaded until the box is checked. I am not aware of any technical reason why that couldn’t have been the way it worked in the first place, and it would go a long way to reassure people that this closed-source extension can’t listen to them unless they want it to. Note that even if the extension were open source it might still be a live question whether it does anything hinky. There’s an excellent chance that it’s a generic machine recognition algorithm that’s been trained to detect OK Google, which training appears in the code as a big lump of meaningless numbers—and there’s no way to know whether those numbers train it to detect anything besides OK Google. Maybe if you start talking about bombs the computer just quietly starts recording…

Mistake number three, finally, is something they got half-right. This is not a core browser feature. Indeed, it’s hard for me to imagine any situation where I would want this feature on a desktop computer. Hands-free operation of a mobile device, sure, but if my hands are already on a keyboard, that’s faster and less bothersome for other people in the room. So, Google implemented this frill as a browser extension—but then they didn’t expose that in the user interface. It should be an extension, and it should be visible as such. Then it needn’t take up space in the core preferences screen, even. If people want it they can get it from the Chrome extension repository like any other extension. And that would give Google valuable data on how many people actually use this feature and whether it’s worth continuing to develop.