I was playing with my new Laptop (a Philco 14E-P686WP) that comes with (argh!) Windows 7. I was gathering information in order to avoid surprises with regards to drivers and hardware-compatibility so I can proceed with the Debian installation By doing that with a new machine, I, usually, peek and poke everywhere, including the Recovery System. I was shocked to find out that this (argh) Windows 7 laptop has a bootable recovery partition loaded with a customized Debian just to run Partclone which installs a Windows factory image. I was about to take some pictures of the process, but I managed to find some in a forum post. Debian is being used to re-install (argh) Windows How sad is that!

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I will be visiting the Open Source Days 2012 next weekend to talk about how to Gitify your life; if you want to meat (sic) up, do let me know. Compared to FOSDEM, I have 150% of the time for ~250% of the content which means I will need to cut some corners, content-wise. That's a pity, but that's the way it is; we will see how it goes. Never having been there before, I am looking forward to both Copenhagen and the Open Source Days. In somewhat related news, FOSDEM's vcsh talk (slides, video) and git-annex talk (slides, video) have been uploaded completely. Thanks to FOSDEM's/Debian's video team; you're awesome! In less related news, I have had the questionable honour of updating and installing one copy of Windows 7, respectively. I guess it's nice that Intel's driver installation utility tells you it expects a maximum of 12 reboots until a fresh installation is set up and if you would like to enter your username & password to auto-login. That Windows itself only took about half a dozen reboots until the several hundreds of updates were installed was a welcome surprise; Windows XP was even worse. Now, if anyone can tell me why audio drivers need a download of 380 MiB, that would be appreciated. Not that this was an uncommon size for every single driver, mind. Installed Size of linux-image-3.2.0-2-amd64 is 104,820.0 kB, btw. On the plus side, Windows 7 was able to automagically download a printer driver once I told it what the network printer's, which it refused to autodiscover, brand and model were.

It has been months since I last put something here, so I think that requires a quick catchup.

Recently I accidentally flooded Planet Debian with my blog feed. This was an accident caused by some of my older blog entries not having valid "Date:" headers. (I use chronicle which parses simple text files to build a blog, and if there is no Date: header present in entries it uses the CTIME of the file(s).) So why did my CTIMEs get lost? Short version I had a drive failure and a PSU failure which lead to me rebuilding a few things and cloning a fresh copy of my blog to ~/hg/blog/. My host is now once again OK, but during the pain the on-board sound started to die. Horribly crackly and sounding bad. I figure the PSU might have caused some collateral damage, but so far thats the only sign I see. I disabled the on-board sound and ordered a cheap USB sound device which now provides me with perfect sound under the Squeeze release of Debian GNU/Linux. In the past I've ranted about GNU/Linux sound. So I think it is only fair to say this time things worked perfectly - I plugged in the device, it was visible in the output of dmesg, and /proc/asound/cards and suddenly everything just worked. Playing music (mpd + sonata) worked immediately, and when I decided to try playing a movie with xine just for fun sound was mixed appropriately - such that I could hear both "song" + "movie" at the same time. Woo. (I'm not sure if I should try using pulse-audio, or similar black magic. Right now I've just got ALSA running.) Anyway as part of the re-deployment of my desktop I generated and pass-phrased a new SSH key, and then deployed that with my slaughter tool. My various websites all run under their own UID on my remote host, and a reverse-proxy redirects connections. So far example I have a Unix "s-stolen" user for the site stolen-souls.com, a s-tasteful user for the site tasteful.xxx, etc. (Right now I cannot remember why I gave each "webserver user" an "s-" prefix, but it made sense at the time!) Anyway once I'd fixed up SSH keys I went on a spree of tidying up and built a bunch of meta-packages to make it a little more straightforward to re-deploy hosts in the future. I'm quite pleased with the way those turned out to be useful. Finally I decided to do something radical. I installed the bluetile window manager, which allows you to toggle between "tiling" and "normal" modes. This is my first foray into tiling window managers, but it seems to be going well. I've got the hang of resizing via the keyboard and tweaked a couple of virtual desktops so I can work well both at home and on my work machine. (I suspect I will eventually migrate to awesome, or similar, this is very much a deliberate "ease myself into it" step.) ObQuote: "Being Swedish, the walk from the bathroom to her room didn't need to be a modest one. " - Cashback.

I have just bought our plane tickets to Managua, so I can finally say this: Yes, many of you will ask what happened, I was bragging everywhere I wanted to go by land, driving from Mexico City to Managua. I'd love to, and I'm sure it's completely doable... But we have family issues to attend on July 21, in Argentina. So we will have a beautiful flight schedule (and carbon footprint) for this July:

June 30

Mexico San Salvador Managua, 17:35-20:30. Yes, this means I will not be in Mexico to cast my vote on July 1st. Well, I had already accepted this would happen... And the price difference was quite sensible.

July 15

Managua San Jos Mexico, 16:25-22:20

July 16

Mexico Santiago Buenos Aires (AEP), 20:30-09:55

July 23

Buenos Aires (EZE) Lima Mexico, 08:35-19:00

Several people have asked me on the best airline options for this trip. In our case, to Managua, it was with TACA, US$518 total. You can get tickets for ~US$30 less, but the flight goes through Panama instead of San Salvador, for an extra 1000Km And instead of ~3hr it makes slightly over 6. Yes, on our way back we will be routed a bit South to San Jos , but it's not as bad, and it's for a very short layover. For Argentina? Well, we have always found LAN to be the cheapest and most convenient. This time, TACA/Avianca was a very close second, which lost due to almost doubling the flight+layover time Why aren't we taking a Mexico Managua Buenos Aires flight instead? Because it's ~US$150 more expensive per person. Not *that* much, but still some money. And by returning to Mexico and having a night at home, we will save us the hassle of carrying Winter clothes to Nicaragua and Summer clothes to Argentina. Oh, and if you are planning on dropping by home while we are away and robbing all of our stuff: There's not that much to take from there, and we have already arranged for somebody to be there while we are away. But thanks for thinking about us, anyway! [update] And what about DebConf12 registration? When is the system opening for us all to register? Soon, dear friends, we are talking about some related issues, and you will have your registrationi open soon.

Inspired by the interview series conducted by Raphael, I started a Norwegian interview series with people involved in the Debian Edu / Skolelinux community. This was so popular that I believe it is time to move to a more international audience. While Debian Edu and Skolelinux originated in France and Norway, and have most users in Europe, there are users all around the globe. One of those far away from me is Nigel Barker, a long time Debian Edu system administrator and contributor. It is thanks to him that Debian Edu is adjusted to work out of the box in Japan. I got him to answer a few questions, and am happy to share the response with you. :) Who are you, and how do you spend your days? My name is Nigel Barker, and I am British. I am married to Yumiko, and we have three lovely children, aged 15, 14 and 4(!) I am the IT Coordinator at Hiroshima International School, Japan. I am also a teacher, and in fact I spend most of my day teaching Mathematics, Science, IT, and Chemistry. I was originally a Chemistry teacher, but I have always had an interest in computers. Another teacher teaches primary school IT, but apart from that I am the only computer person, so that means I am the network manager, technician and webmaster, also, and I help people with their computer problems. I teach python to beginners in an after-school club. I am way too busy, so I really appreciate the simplicity of Skolelinux. How did you get in contact with the Skolelinux/Debian Edu project? In around 2004 or 5 I discovered the ltsp project, and set up a server in the IT lab. I wanted some way to connect it to our central samba server, which I was also quite poor at configuring. I discovered Edubuntu when it came out, but it didn't really improve my setup. I did various desperate searches for things like "school Linux server" and ended up in a document called "Drift" something or other. Reading there it became clear that Skolelinux was going to solve all my problems in one go. I was very excited, but apprehensive, because my previous attempts to install Debian had ended in failure (I used Mandrake for everything - ltsp, samba, apache, mail, ns...). I downloaded a beta version, had some problems, so subscribed to the Debian Edu list for help. I have remained subscribed ever since, and my school has run a Skolelinux network since Sarge. What do you see as the advantages of Skolelinux/Debian Edu? For me the integrated setup. This is not just the server, or the workstation, or the ltsp. Its all of them, and its all configured ready to go. I read somewhere in the early documentation that it is designed to be setup and managed by the Maths or Science teacher, who doesn't necessarily know much about computers, in a small Norwegian school. That describes me perfectly if you replace Norway with Japan. What do you see as the disadvantages of Skolelinux/Debian Edu? The desktop is fairly plain. If you compare it with Edubuntu, who have fun themes for children, or with distributions such as Mint, who make the desktop beautiful. They create a good impression on people who don't need to understand how to use any of it, but who might be important to the school. School administrators or directors, for instance, or parents. Even kids. Debian itself usually has ugly default theme settings. It was my dream a few years back that some kind of integration would allow Edubuntu to do the desktop stuff and Debian Edu the servers, but now I realise how impossible that is. A second disadvantage is that if something goes wrong, or you need to customise something, then suddenly the level of expertise required multiplies. For example, backup wasn't working properly in Lenny. It took me ages to learn how to set up my own server to do rsync backups. I am afraid of anything to do with ldap, but perhaps Gosa will help. Which free software do you use daily? Nowadays I only use Debian on my personal computers. I have one for studio work (I play guitar and write songs), running AV Linux (customised Debian) a netbook running Squeeze, and a bigger laptop still running Skolelinux Lenny workstation. I have a Tjener in my house, that's very useful for the family photos and music. At school the students only use Skolelinux. (Some teachers and the office still have windows). So that means we only use free software all day every day. Open office, The GIMP, Firefox/Iceweasel, VLC and Audacity are installed on every computer in school, irrespective of OS. We also have Koha on Debian for the library, and Apache, Moodle, b2evolution and Etomite on Debian for the www. The firewall is Untangle. Which strategy do you believe is the right one to use to get schools to use free software? Current trends are in our favour. Open source is big in industry, and ordinary people have heard of it. The spread of Android and the popularity of Apple have helped to weaken the impression that you have to have Microsoft on everything. People complain to me much less about file formats and Word than they did 5 years ago. The Edu aspect is also a selling point. This is all customised for schools. Where is the Windows-edu, or the Mac-edu? But of course the main attraction is budget.The trick is to convince people that the quality is not compromised when you stop paying and use free software instead. That is one reason why I say the desktop experience is a weakness. People are not impressed when their USB drive doesn't work, or their browser doesn't play flash, for example.

Yesterday, I've finalized Weblate 0.4. It improved handling of plural strings, added documentation and implemented support for secondary languages. If you ask for 0.3, well I managed to release two versions in the day, but I expect to slow down this pace. Full list of changes for 0.3:

• Better display of source for plural translations.
• New documentation in Sphinx format.
• Displays secondary languages while translating.
• Improved error page to give list of existing projects.
• New per language stats.

Full list of changes for 0.4:

• Added usage guide to documentation.
• Fixed API hooks not to require CSRF protection.

You can find more information about Weblate on it's website, the code is hosted on Github. If you are curious how it looks, you can try it out on demo server. You can login there with demo account using demo password or register your own user. Weblate is now also being used https://l10n.cihar.com/ as official translating service for phpMyAdmin, Gammu and others.

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FedEx has had some issues in my area. There for awhile, they kept returning packages as undeliverable, saying the address was bad. It wasn t. Just because their GPS can t find it or their driver doesn t know it doesn t mean it doesn t exist. A map, a real map, would have done it. I had this kind of conversation with them once. Me: So you re returning my package to the sender. FedEx: Yes sir, the address was wrong. Me: No, it wasn t. [ we confirm we're talking about the same address. ] FedEx: Our driver says it doesn t exist. Me: I ve lived here for [x] years. I do know my address. FedEx: Maybe it s just new. Me: Someone has lived at this spot since the 1890s. FedEx: Hmm. I don t know then. Me: How about I give you directions? FedEx: Well, OK, I guess I could send directions. But they probably won t see them for three days. Me: Where will my package be by then? FedEx: Hard to say. Me: Do you people have cell phones maybe? FedEx: No. Me: Well, OK then Lately we have been noticing that the driver throws the package from the truck without stopping. We find them all over the yard. Unless it s big, in which case he puts it on the porch, puts a completely useless sticker on the door saying We delivered your package to right here! , and doesn t ring the doorbell. And panics due to the muddy road. The FedEx driver once told Terah, I almost got stuck on that muddy road! What s the good one? Terah: Well, which one did you take? [ he describes ] Terah: [ serious ] That IS the good road. FedEx: [ turning pale ] Oh my. I don t know if I can make it back to the highway. Terah: Well, I suppose I could get the boys in the car and drive you into town FedEx: [ embarrassed and more pale ] Uhm that s OK uhm I think A *month* later, we got another FedEx package. The driver called me at work, saying, I just don t know how I m going to get down those roads. Can I deliver the package to you here? (10 miles away). I said yes, and managed to suppress a significant snicker at his obvious relief. FedEx drivers seem to come and go. The UPS driver, on the other hand, knows the names of our boys, our cat, and puts anything small behind the storm door so it won t blow away if we re not home. And he gets a great big laugh when I tell him that the FedEx drivers are afraid of our roads. Haha, he thinks THAT S mud? Obviously he never drives in Butler County.

I followed Gregor s evolution within Debian because I used to be somewhat active in the Perl team. His case is exemplar because it shows that you don t need to be an IT professional to join Debian and to make a difference. His QA page is impressive with hundreds of packages maintained and hundreds of non-maintainer uploads too. While he started out slowly, I remember meeting him at Debconf 7 in Edinburgh and after that he really got more implicated. Again a case of someone joining for technical reasons but getting more involved and staying there for social reasons! Let s jump into the interview and learn more about him. Raphael: Who are you? Gregor: I m 41 years old, and I live in Innsbruck, Austria, in a shared apartment with a friend of mine. In my day job, I m working at the regional addiction prevention agency, so I m one of the few Debian guys who s not an IT student or professional. I started maintaining packages in 2006, and I am a DD since April 2008. Raphael: How did you start contributing to Debian? Gregor: After having used Debian on servers for some years, I finally switched to it on the desktop after some procrastinating. Soon afterwards I wanted to know more about the making-of , started to join mailing lists, filed bugs, and tried to learn packaging. Luckily I quickly found a permanent sponsor Tony Mancill, and we re still co-maintaining each others packages. And when I packaged my first Perl modules, Gunnar Wolf invited me to join the Debian Perl Group, an offer I accepted a few days later. And I m still there Later, the NM process, although it involved some waiting times, was also a good learning experience due to my AM Wouter Verhelst. (And in the meantime the organization of the NM process has vastly improved, from what I hear.) So my starting point for joining Debian was my curiosity but what really helped me to find my way into the project was the support of the people who invited and helped me. Raphael: What s your biggest achievement within Debian or Ubuntu? Gregor: I m not sure I can name a single big achievement but I guess I can say that my contributions to the Debian Perl Group have helped to make and keep the team a success story. Raphael: The pkg-perl team seems to work very well. As an active member, can you explain us how it is organized? How do you explain its success? In particular it seems to be a great entry point for new contributors. Gregor: The team is huge, both in numbers of members and packages (over 2200). Since last DebConf we manage our source packages in git, we have 2 mailing lists and an IRC channel, and we manage to keep an overview by using PET, the Package Entropy Tracker. It s true that we get new members on a regular basis; we try to invite people (like it happened to me 6 years ago ) but there are also quite a few new contributors who find our docs and introduce themselves on the mailing list. Maybe someone should conduct a study and ask them what motivated them to join. We hand out group membership/commit access quickly, and we try to mentor new contributors actively during their early times in the group. Some of them leave for other projects after some time, but many also stay and become DDs later. I m not sure what the reasons for the group s success are, maybe a combination of:

• a culture in the group (and also in the upstream Perl community) that s based on fun, cooperation, and respect;
• the fact that packaging Perl modules is most of the time quite easy;
• a great set of tools, and also (hopefully) useful documentation;
• a bunch of relaxed people who are open to newcomers and try to help each other.

For everyone interested in joining the Debian Perl Group, our Welcome page on the wiki is a good starting point. Raphael: What are your plans for Debian Wheezy? Gregor: Nothing overly exciting. What I should do is getting a newer JabRef into Debian (which involves packaging some new Java libraries any takers?). A solution for libdatetime-timezone-perl (which ships timezone data converted to Perl modules and tends to get outdated when the timezone data change) would be nice; let s see if #660404 leads to some results And some Perl packages will also need a bit of work for the hardening build flags release goal (cf. #657853). Raphael: What s the biggest problem of Debian? Gregor: Inertia. While I really like the fact that Debian is a volunteer project, and that every contributor works when and on what they decide to work on, I get the feeling that Debian could do better in moving forward, innovating, taking decisions. I also think that more uniformity in managing source packages would make things easier; it s quite amazing to see how many source formats, packaging helpers, patch systems, RCSs etc. are used all over the archive. I m not advocating for mono-cultures, and I consider this diversity a strength in general, but having to find out first how this particular package works when preparing a bug fix can be annoying. On the bright side, I think that the myth Debian and its mailing lists are mostly about flames can be seen as dispelled in the meantime. Sure, sometimes the tone could be a bit more civil, but in general most of the interactions I ve seen in the last years were friendly and helpful. IMO, the Debian Project consists of mostly nice and cooperative people, and that s what makes it fun for me. Raphael: You re one of the most dedicated participants to RCBW (Release Critical Bugs of the Week), an initiative to fix RC bugs every week. How much time do you spend on it? What would you advise to people who are considering to join the movement? Gregor: I got into the habit of fixing RC bugs after having been invited to my first Bug Squashing Party in Munich some years ago. During this weekend I saw that fixing RC bugs can be fun, is often not that difficult, and gives a warm fuzzy feeling I can definitely recommend attending a BSP if one happens to be organized near you. After tasting blood at this first BSP I tried to continue looking at RC bugs, and I guess I spend something around half an hour per day on it. I usually blog about it once a week, in order to motivate others to join in. And joining is easy: just take a look at the tips people like Zack, Vorlon, or me have written. You don t have to be a DD to help, many of my NMUs are based on patches that others kindly prepare and send to the BTS kudos! Another nice aspect is that the RC bug list contains problems from different fields: general packaging problems, language-specific issues, policy violations, etc. So there s something for everybody, and you don t have to be an expert in all fields to fix a specific bug. What s rewarding about fixing RC bugs is not only the feeling of accomplishment and the knowledge about having helped the next release I also received quite a few Thank you mails from maintainers who were busy at that time and appreciated the help. Raphael: Do you have wishes for Debian Wheezy? Gregor: Well, there s not so much left of the Wheezy release cycle if we manage to freeze in June Some quick thoughts for Wheezy and Wheezy+1:

• Obviously, getting multi-arch and the hardening build flags as far as possible would be good.
• What I like is the idea of the time-based freeze, and I hope it will work out in June. And then I hope that the freeze will be shorter this time than during the last 2 releases.
• Unless I m missing something, the CUT discussions have more or less died down; IMO that s a pity because there are users who run testing and would like to avoid the several month long freeze. Maybe someone can come up with new ideas for Wheezy+1
• Too late for broad adoption in Wheezy but still: What constantly annoys me is the handling of conffiles during upgrades (when I want to keep changed values but at the same time want to add new variables). Config::Model seems to be the best idea so far for configuration upgrades but it s not yet widely adopted.

Raphael: Is there someone in Debian that you admire for their contributions? Gregor: There are many people in Debian I admire, too many to name them all. The first one that comes to my mind is Russ Allbery who not only does great work from lintian to Debian policy but who also sets a great example of communicating in a perfectly polite and respectful way even in heated discussions.

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Thank you to Gregor for the time spent answering my questions. I hope you enjoyed reading his answers as I did. Note that older interviews are indexed on wiki.debian.org/PeopleBehindDebian.

Subscribe to my newsletter to get my monthly summary of the Debian/Ubuntu news and to not miss further interviews. You can also follow along on Identi.ca, Google+, Twitter and Facebook.

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Packt Publishing has offered phpMyAdmin to sponsor some coding contest with books. The contest is already running since Monday and we have first winner, but still, your chances are pretty high. So in case you are interested in having Mastering phpMyAdmin 3.4 for Effective MySQL Management, go ahead and check out the contest rules.

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I recently got to rebuild an Android NDK with a fresh toolchain again, and hit an interesting problem. I actually had hit it before, but only this time I fully analyzed what s going on. [As a side note, if you build such a NDK, don't use mpfr 3.1.0, as there is a bug in the libtool it ships] Linking an application or a library pulls many things, that aren t part of the code being built. One of these many things is the libgcc static library. Part of libgcc consists in an implementation of the platform ABI. On Android systems, this means the ARM EABI. GCC, when compiling some instructions, will generate ABI calls. For example, integer divisions may call __aeabi_idiv. Consider the following minimized real world scenario:

$ echo "int foo(int a) return 42 % a; " > foo.c
$ arm-linux-androideabi-gcc -o libfoo.so -shared foo.c -mandroid

GCC will emit a call to __aeabi_idivmod for the % operation. With GCC 4.6.3, this function is in _divsi3.o under libgcc.a. That function itself calls __aeabi_idiv0, which lives in _dvmd_lnx.o under libgcc.a. When statically linking, ld will thus include foo.o, _divsi3.o and _dvmd_lnx.o, meaning it will include all functions from these object files. That is, foo, __divsi3, __aeabi_idiv, __aeabi_idivmod, __aeabi_idiv0 and __aeabi_ldiv0. And more than being included, these functions are exported, because symbol visibility in libgcc.a is default. So while we expect exporting foo from our library, we re actually exporting much more, including functions that just happened to be near the ones that our code (indirectly) uses. Now, let s say we want to build another library, using that foo function from libfoo:

$ cat > bar.c <<EOF
extern int foo(int a);
long long bar(long long a) return foo(a) % a;
EOF
$ arm-linux-androideabi-gcc -o libbar.so -shared bar.c -mandroid

(The code above has absolutely no meaning, it just triggers the same function calls as what I was getting in the actual real world case) When statically linking the above code, GCC will generate a call to __aeabi_ldivmod, which calls __aeabi_ldiv0, and many other things, directly or indirectly. When linking as above, nothing particularly nasty is going to happen. However, linking as above is actually wrong: the resulting library has an undefined reference to the foo symbol, and doesn t depend on libfoo. At runtime, if libfoo wasn t already loaded somehow, loading libbar would fail. The proper way to link is the following:

$ arm-linux-androideabi-gcc -o libbar.so -shared bar.c -mandroid -L. -lfoo

A feature of ELF static linking is that when it resolves undefined symbols, the linker will choose to use the first occurrence of a symbol it finds in the various objects and libraries given on its command line. So with the command line above, for each __aeabi_* symbol, it will first look in libfoo if there isn t one. And while __aeabi_ldivmod is not in libfoo, __aeabi_ldiv0 is (see above). So instead of including the code for __aeabi_ldiv0 from libgcc.a, it will call the copy from libfoo. This wouldn t be so much of a problem if __aeabi_ldiv0 wasn t a weak symbol. Enters faulty.lib. In the real world case, libfoo is loaded by the system dynamic linker, and libbar by faulty.lib. When resolving symbols for libbar, faulty.lib has to resolve libfoo symbols with the system linker, using dlsym(). On Android, dlsym() returns NULL for weak (defined) symbols, so faulty.lib can t resolve __aeabi_ldiv0. The real world case wasn t a problem with GCC 4.4.3 from the vanilla Android NDK because in that GCC version, __aeabi_ldivmod doesn t call __aeabi_ldiv0. This wouldn t happen if shared libraries wouldn t expose random platform ABI specific bits depending on what they use and depending on other symbols that happen to be in the same object files. A similar issue happened a little while ago on Debian powerpc because a shared library was exporting ABI specific bits. Even worse, the toolchain was assuming the symbols would come from libgcc.a and generated wrong relocations for these symbols. Update: Interestingly, the __aeabi_* symbols are hidden, in libgcc.a as provided on the Debian armel port.

You work with Python for a while and you'll become familiar with printing a method and getting I think there is room for one more explanation on the internet, since I've never seen it diagrammed out (maybe for good reason!). In the above diagram on the left, we have the fairly simple conceptual model of a class with a function. One naturally tends to think of the function as a part of the class and your instance calls into that function. This is conceptually correct, but a little abstracted from what's actually happening. The right attempts to illustrate the underlying process in some more depth. The first step, on the top right, is building something like the following: As this illustrates, the above code results in two things happening; firstly a function object for function is created and secondly the __dict__ attribute of the class is given a key function that points to this function object. Now the thing about this function object is that it implements the descriptor protocol. In short, if an object implements a __get__ function; then when that object is accessed as an attribute of an object the __get__ function is called. You can read up on the descriptor protocol, but the important part to remember is that it passes in the context from which it is called; that is the object that is calling the function. So, for example, when we then do the following: what happens is that we get the attribute function of f and then call it. f above doesn't actually know anything about function as such what it does know is its class inheritance and so Python goes searching the parent's class __dict__ to try and find the function attribute. It finds this, and as per the descriptor protocol when the attribute is accessed it calls the __get__ function of the underlying function object. What happens now is that the function's __get__ method returns essentially a wrapper object that stores the information to bind the function to the object. This wrapper object is of type types.MethodType and you can see it stores some important attributes in the object im_func which is the function to call, and im_self which is the object who called it. Passing the object through to im_self is how function gets it's first self argument (the calling object). So when you print the value of f.function() you see it report itself as a bound method. So hopefully this illustrates that a bound method is a just a special object that knows how to call an underlying function with context about the object that's calling it. To try and make this a little more concrete, consider the following program: Running this gives output something like To pull it apart; we can see that Foo.__dict__['function'] is a function object, but then f.function is a bound method. The bound method's im_func is the underlying function object, and the im_self is the object f: thus im_func(im_self) is calling function with the correct object as the first argument self. So the main point is to kind of shift thinking about a function as some particular intrinsic part of a class, but rather as a separate object abstracted from the class that gets bound into an instance as required. The class is in some ways a template and namespacing tool to allow you to find the right function objects; it doesn't actually implement the functions as such. There is plenty more information if you search for "descriptor protocol" and Python binding rules and lots of advanced tricks you can play. But hopefully this is a useful introduction to get an initial handle on what's going on!

One of the best way to add SNMP support to an application is the use of AgentX protocol: an application can act as a subagent and handle requests from a master agent using AgentX protocol. The most widespread implementation for such a task is the one from Net-SNMP. TL;DR: An application asynchronously leveraging Net-SNMP AgentX implementation has many opportunities to get stuck when the master agent becomes temporarily unavailable. A mostly efficient workaround is to dedicate a master agent for AgentX and delegate MIB handling to a subagent.

Pinging the master agent Net-SNMP uses an event-based model. It also provides some synchronous functions but they are built on top of the asynchronous ones. It is shipped with its own event loop. Therefore, Net-SNMP AgentX protocol implementation seems a fine choice to add SNMP support to an event-based program, for example in Keepalived, a VRRP daemon and a monitoring daemon for LVS clusters. Unfortunately, an AgentX subagent is expected to check, at a regular interval, if the master agent is alive . This is handled automatically with Net-SNMP implementation as long as you call run_alarms() function which will call agentx_check_session():

/*
 * check a session validity for connectivity to the master agent.  If
 * not functioning, close and start attempts to reopen the session 
 */
void
agentx_check_session(unsigned int clientreg, void *clientarg)
 
    /* [...] */
    DEBUGMSGTL(("agentx/subagent", "checking status of session %p\n", ss));
    if (!agentx_send_ping(ss))  
        snmp_log(LOG_WARNING,
                 "AgentX master agent failed to respond to ping.  Attempting to re-register.\n");
        /*
         * master agent disappeared?  Try and re-register.
         * close first, just to be sure .
         */
        agentx_unregister_callbacks(ss);
        agentx_close_session(ss, AGENTX_CLOSE_TIMEOUT);
        /* [...] */
        if (main_session != NULL)  
            /* [...] */
            main_session = NULL;
            agentx_reopen_session(0, NULL);
         
        else  
            snmp_close(main_session);
            main_session = NULL;
         
      else  
        DEBUGMSGTL(("agentx/subagent", "session %p responded to ping\n",
                    ss));
     
 

This piece of code will end up calling (directly or indirectly) the following functions¹ which are using agentx_synch_response():

• agentx_send_ping()
• agentx_open_session()
• agentx_reopen_session()
• agentx_close_session()
• agentx_register()
• agentx_unregister()
• agentx_register_index()
• agentx_unregister_index()
• agentx_add_agentcaps()
• agentx_remove_agentcaps()

agentx_synch_response() will synchronously wait for an answer from the master agent. Your event-based program will just sit here doing nothing while this happens. For example, keepalived may be unable to send VRRP probes resulting in some serious havoc in your cluster. Functions prefixed by agentx_ are not part of NetSNMP API and could therefore be rewritten to do their work asynchronously. Unfortunately, talk is cheap. Moreover, there exists other deep paths that will block a subagent. For example, the low-level connection to the master agent (using TCP or a Unix socket, but not with UDP) will use a blocking connect() call. It seems quite difficult to fix this. Here are some (partial) workarounds:

• Call agentx_check_session() less often. The default interval is 15 seconds. Disabling it completely or using a very high value is not advised because this function is the only way to reestablish a connection to the master agent when it is, for example, restarted. Here is how to change the delay to 120 seconds:

  netsnmp_ds_set_int(NETSNMP_DS_APPLICATION_ID,
                     NETSNMP_DS_AGENT_AGENTX_PING_INTERVAL, 120);
  

• Don t call agentx_check_session() if we know the master agent is alive. For example, if it just sent us a new request, no need to ping it. I have written a patch implementing such a workaround. The ABI is left untouched, therefore, you only need to recompile Net-SNMP libraries.
• Use a lower timeout and no retry. By default, the timeout for synchronous requests is 1 second and a failed request will be retried 5 times. Because several synchronous functions are used in a row, you may be trapped for as long as 30 seconds with those settings. Here is how² to disable the retry mechanism and to set the timeout to a very low value:

  static int
  snmp_setup_session_cb(int majorID, int minorID,
                void *serverarg, void *clientarg)
   
      netsnmp_session *sess = serverarg;
      sess->timeout = ONE_SEC / 3;
      sess->retries = 0;
      return 0;
   
  void some_init_function()
   
      /* [...] */
      snmp_register_callback(SNMP_CALLBACK_LIBRARY,
         SNMP_CALLBACK_SESSION_INIT,
         snmp_setup_session_cb, NULL);
      /* [...] */
   
  

Unresponsive master agent Why is the master agent unresponsive? snmpd is also an event-based program and, trust me, there are a lot of places where it will become unresponsive. Here are two examples:

• When using the pass or the pass_persist directive, Net-SNMP will block until the delegated command outputs a complete line.

  /* var_extensible_pass() in agent/mibgroup/ucd-snmp/pass.c */
  /*
   * valid call.  Exec and get output 
   */
  if ((fd = get_exec_output(passthru)) != -1)  
      file = fdopen(fd, "r");
      if (fgets(buf, sizeof(buf), file) == NULL)  
          fclose(file);
          wait_on_exec(passthru);
          /* [...] */
          continue;
       
      /* [...] */
      fclose(file);
      wait_on_exec(passthru);
      /* [...] */
   
  

• DISMAN-PING-MIB implementation will just hang while pinging the remote host. If the host is down and you have requested 5 probes with a timeout of 1 second, snmpd will be unresponsive for 5 seconds. A similar problem exists with DISMAN-TRACEROUTE-MIB.

Minimal master agent More and more code is running in the main agent. You cannot expect it to not block. But we could add a minimal master agent to the mix: it will handle only a few MIB modules by itself while most MIB modules will be delagated to a complete agent running as a subagent. Your own subagent will connect to the minimal master agent. It is quite easy to turn snmpd into a subagent: just use -X flag. We should also disable unwanted MIB modules for each agent with -I flag. For the minimal master agent, we only enable some modules. All other modules³ will be served by snmpd acting as a subagent.

$ MODS="snmp_mib,sysORTable,usmConf,usmStats,usmUser,vacm_conf,vacm_context,vacm_vars"
$ snmpd -Lsd -Lf /dev/null -u snmp -g snmp \
>   -C -c /etc/snmp/snmpd.master.conf \
>   -p /var/run/snmpd.master.pid \
>   -I $MODS
$ snmpd -Lsd -Lf /dev/null -u snmp -g snmp \
>   -p /var/run/snmpd.pid -X \
>   -I -$MODS

Access control configuration should be placed in /etc/snmp/snmpd.master.conf, as well as master agentx directive. Other directives (like pass, pass_persist, load, sysname, ) in /etc/snmp/snmpd.conf. The minimal master agent is very unlikely to block and while the ground cause is still here, it is now very much mitigated. You may extend this solution by splicing snmpd into several subagents: one handling safe modules, one handling pass and pass_persist stuff and a last one for unsafe modules (like DISMAN-PING-MIB).

---

1. agentx_reopen_session() will call agentx_close_session() and agentx_open_session(). agentx_register() and the following functions will be called by those two functions.
2. NETSNMP_DS_AGENT_AGENTX_TIMEOUT and NETSNMP_DS_AGENT_AGENTX_RETRIES variables are only used by the master agent, not by a subagent.
3. Use snmpd -Dmib_init -H to get the list of modules. You may want to add smux module to the master agent.

At May First/People Link we have been using KVM for several years now and recently I have been running KVM instances on my local laptop. I'm pleased to see all the work that has gone into libvirt, which seems like a robust and full-featured suite of tools for managing many virtualization technologies, including KVM. However, we don't use it at May First/People Link for a number of reasons. The most pressing is that it runs all virtual guests as the same user, but also because it offers far more features than we need (such as graphical access to virtual server, which we don't need since none of our guest servers run X). On May First/People Link hosts, we are using a relatively simple set of bash scripts (accessible via git at git://lair.fifthhorseman.net/~dkg/kvm-manager). These scripts re-use many tools we are already familiar with to build and launch kvm guests. Each guests runs as a dedicated non-provileged user, with a console available using screen, and the kvm process is managed using runit. Since our admins are familiar with these tools already, the learning curve involved is much less steep. Despite the relative simplicity of kvm-manager, it was still more complicated and involved than I wanted on my laptop. Additionally, I wanted to fully understand every piece of the puzzle and separating out user privileges wasn't important to me. So - I wrote the following bash script to launch virtual servers. It assumes you are using logical volume manager. Some editing required if you want to re-use it.

#!/bin/bash
# manage a virtual server
# add /etc/udev/rules.d/92-kvm.rules with the following line (change "jamie" 
# to the group you are running as and vg_animal0 to the name of your volume 
# group):
# ACTION=="change", SUBSYSTEM=="block", ATTR dm/name =="vg_animal0-*_root", GROUP="jamie"
#
# install a new server by:
# * create logical volume with the name: servername_root
# * $0 servername start /usr/local/share/ISOs/default.iso
bridge=virbr0
user=jamie
base=/home/jamie
server="$1"
vg=vg_animal0
# modify server memory here
mem=768
command="$2"
[ -z "$command" ] && command=start
die ()  
  printf "$1\n"
  exit 1
 
cdarg=
if [ -n "$3" ]; then
  [ ! -f "$3" ] && die "Third argument should be path to cd iso. Can't find that path."
  cdarg="-cdrom $3"
fi
function start()  
  lvname="$ vg -$ server _root"
  # trigger udev to ensure we have proper ownership of the block device
  sudo udevadm trigger --subsystem-match=block --attr-match=dm/name="$lvname"
  lv="/dev/mapper/$lvname"
  [ ! -e "$lv" ] && die "Can't find $lv"
  sudo modprobe -v tun   die "Failed to modprobe tun module"
  # create network device if it doesn't already exist
  ip tuntap   grep "$tap"   sudo ip tuntap add dev "$tap" mode tap user "$user"   die "Failed to create device $tap"
  # bring up device if it's not already up
  ip link   grep " $tap "   sudo ip link set "$tap" up   die "Failed to set $tap to up"
  # add the device to the bridge so it get use the upstream network connections
  /sbin/brctl show   grep "$tap"   sudo brctl addif "$bridge" "$tap"   die "Failed to add tap to bridge"
  # launch kvm in a screen session
  screen -S "$server" kvm -drive "file=$lv,if=virtio,id=hda,format=raw" -m "$mem" -device "virtio-net-pci,vlan=1,id=net0,mac=$mac,bus=pci.0" -net "tap,ifname=$tap,script=no,downscript=no,vlan=1,name=hostnet0" $cdarg -nographic   die "Failed to start kvm" 
 
function cleanup()  
  read -p "Please shutdown the host first then hit any key to continue..."
  sudo brctl delif "$bridge" "$tap"
  sudo ip link set "$tap" down
  sudo ip tuntap del mode tap dev "$tap"
 
# generate reproducible mac address
mac="$(printf "02:%s" "$(printf "%s\0%s" "$(hostname)" "$ server "   sha256sum   sed 's/\(..\)/\1:/g'   cut -f1-5 -d:)" )"
tap="$ server 0"
case "$command" in
  start)
    start
    ;;
  cleanup)
    cleanup
    ;;
  *)
    die "Please pass start or cleanup as first argument"
esac

Released a few hours ago, here is the monthly report of DPL activities for February 2012.

---

Howdy, dear Project Members,
here's another round of updates about what has happened in DPL land, this time during February 2012. Highlights Quit a bit of highlights for this month:

• The first item is not pleasant but important. Early February I've submitted to the attention of the Technical Committee the upload of multi-arch enabled dpkg to the archive. The Technical Committee quickly reached a decision. Shortly afterwards an upload to experimental has happened and discussions on -devel ensued. Please help out with testing.
• Thanks to IBM and OSUOSL we have some new fairly capable (virtual) machines for powerpc* ports. See the announcement for more info. In particular, please note the call for powerpc64 porters. If you're interested in contributing to such a port, please get in touch with DSA.
• Google Summer of Code project is up again. As usual, it is a good chance to get some work done and, more importantly, to let students who are passionate about Free Software discover Debian. I've delegated the task of GSoC admins --- thanks Ana, Gergely, and Sukhbir! A call for project proposals has already been sent out; there isn't much time left, so please hurry up and drop your ideas to the wiki page and contact the soc-coordination mailing list.
• A couple of important discussions have been going on on -project. The first is the old "trademark vs DFSG" discussion. I've posted there results from legal advice that I've sought on the matter, based on your suggestions. Then, I've posted a proposal on how to deal with trademarks issues in the archive.
• The second discussion is about Debian affiliation with OSI. We've been approached by OSI about that, as I've summarized on -project. Helped by the feedback received, I've decided to go ahead with affiliation and I'm now discussing with OSI representative the next steps.
• The long running work on software patent issues in the archive has been concluded publishing a policy on the matter. We now have a contact point and legal advice with whom we can discuss specific issues if/when they arise; hopefully that would help us to discriminate actual issues in the archive (if any) from the vast amount of FUD in the area.

Talks, interviews, and the like

• Following up Debian related talks at FOSDEM, I've been interviewed, together with Lars Wirzenius and Wookey, for The Register.
• I've took part at a FOSDEM panel session on comparing the organization of local user groups, ambassadors, and the like. We've mostly to learn from others in this area, but I've took the change to summarize what we currently have in a slide deck.

Sprints Plenty of sprints related news!

• DSA and the Groupware team will be holding sprints later on in March, while DAM / FrontDesk are having one right now co-located with the BSP in Moenchengladbach
• the video team sent out a report for their sprint back in November
• debbugs (AKA bugs.debian.org) hackers are organizing a sprint to get people interested in contributing to the code base up to speed. If you're, drop a line in the thread

It would be amazing to have an average of one sprint per month for 2012, and we're on good track for it. If you want to help, organize one for your team as documented on the wiki. Legal stuff

• Thanks to SPI, we've established contacts with the owners of debian.eu, domain we believe we legitimately own. As a first step they've set up HTTP redirection from debian.eu to debian.org (instead of a computer hardware shop, as it was before) and we're now discussing actual transfer of domain ownership to a Debian Trusted Organization.
• We've contacted the Japanese trademark office to transfer the "debian" trademark there to SPI. Thanks to the previous owners (all Debian developers or contributors) for agreeing to the move. Now "only" a nasty pile of paperwork remains to be done.

Appointments In addition to the GSoC admins delegation (see above), I've agreed with former secretary Kurt Roeckx to reappoint him as a secretary for another year. Many thanks, Kurt! Miscellaneous

• We have been invited to attend the OpenStack summit in April and have a presence there, free of charge. Loic Dachary, active member of the OpenStack packaging team in Debian, has agreed to go and represent Debian there. Thanks a lot to Stefano Maffulli for the invitation and to Loic for his availability!
• We are in the process of joining as a project, instead of relying on individual maintainers as in the past the ISC forum to get access to embargoed vulnerability information for important pieces of software such as BIND and DHCP. They've kindly offered us membership free of charge. I've submitted a draft of the membership agreement to SPI and I'm waiting for their decision.
• Steady progress on the front of periodic budget reports, thanks to the work of Martin Michlmayr. We've discussed at length during FOSDEM and agreed on procedures to query the state of Debian finances that work for both auditors and the DPL. Martin has also set up a shared ledger repository and already checked in into it a lot of money transactions for the past few years not from all trusted organizations yet, though. Have faith, we'll get there

Happy Debian hacking.

---

PS as usual, the boring day-to-day activity log is available at master:/srv/leader/news/bits-from-the-DPL.*

If you ever used filelight or baobab you probably know how useful they are. If you didn't, then you missed a lot on how you can spot (and fix) where your disk space is wasted.

With my recent attempt to upgrade to GNOME 3 which, because of its innate property to be useless and counter-productive, actually made me to use Xfce4 with a mix of GNOME aplications (since Xfce lacks a few functionalities here and there), I ran into all sorts of problems.

As a side note, Xfce4 is quite decent, but if you like some icons on your panels to be left aligned and some right aligned, you should know that you can add a Separator item to the panel, right click on it -> Properties and tick the Expand* check box. And if you also set the Transparent style, it will look nice, too.

Back to the topic. With my mix of Xfce and Gnome apps, I configured my top panel to contain a Free Space Checker for my /home file system and today it alerted me that I was low on disk space, so I started baobab to check what I can clean up.

When I found a possible suspect, I wanted to open the directory with a file browser, but, instead, Totem was started and started trying to queue all the files in the offending directory. The problem is that one way or another, Totem (or VLC) was configured to be the default handler for directories instead of the file manager.

The solution is simple, open with an editor the file ~/.local/share/applications/mimeapps.list and search for the line starting with inode/directory= and you'll see something like:

inode/directory=nautilus-folder-handler.desktop;baobab-usercreated.desktop;vlc-usercustom.desktop;

Remove the offending part, vlc-usercustom.desktop;, save the file and try again to open that directory from baobab. If you are double-lucky :P and now it opens with Totem, you will have to remove a reference to a "totem-usercustom.desktop;" or something of that sort. Now, on my system, that line looks like this:

inode/directory=nautilus-folder-handler.desktop;baobab-usercreated.desktop;

And now it works as expected**

* I suppose it's called like that in English, I have my desktop in Romanian
** Except that I would like it to start my desktop preferred file manager, not Nautilus, but that's another issue.

I've recently acquired an UMTS USB stick, a ZTE MF190 (USB ID 19d2:0117/19d2:2000, after and before mode switch, the second ID can be seen while the stick offers its data partition for Windows driver installation). Naturally I wanted to use the stick with Debian. Normally that is no problem at all (as long as you've usb-modeswitch, modemmanager, ppp and a kernel configured with CONFIG_USB_SERIAL, the driver for your device, most likely CONFIG_USB_SERIAL_OPTION in this case, and CONFIG_PPP installed; in short a Debian standard kernel plus network-manager with its recommended packages does the trick). So why write about this at all? Simple: if you have KDE SC 4.7 installed (from experimental), then you need to recompile networkmanagement, the source package building the Plasma widget for controlling the NetworkManager under KDE, as there have been incompatible changes (see e.g KDE bug #282453 for one related bug), which cause a crash after PIN entry. To do that, just follow the few easy steps below:

1. Download the networkmanagement source package: dget -d http://cdn.debian.net/debian/pool/main/n/networkmanagement/networkmanagement_0.9.0-1.dsc (please note, that the version available in Debian might have changed, check the latest version on the PTS page).
2. Build the source package. (Make sure you build in an experimental chroot, otherwise you end up with the same binary.)
3. Install the binary package(s) you just built (most likely plasma-widget-networkmanagement and maybe the debug package).
4. Restart your KDE session.

Today I went to the Laufsporttag Winthertur, another 11km run. Overall it was a smaller event (about a third of participants) than the Bremgarter Reusslauf; the organisation was OK, but you could see that it was smaller-scale. The big difference was that this was definitely not a flat course; the official course lists 150m gain in altitude, my Garmin recorded 220m (given that it has a barometric altimeter, and that the course was hard, I tend\^Wwant to believe the latter). The course starts with 50m of flat, and then up and up until you're in the woods, at which point it's a one third flat, one third down, one third up course; by the 8th km or so, you start the final descent (back to the starting point), and you simply go down and down for a long while, until the final (about 800m) flat distance. You can see a nice graph of the elevation profile here. I thought that since I'm not used to hills, I will simply go slower, and finish about 10 minutes later. However, I definitely underestimated the competition effect , and how much one can get into the spirit of the race . The end effect was that by the official timer, I finished about 1m30s faster than the previous race. I was so glad that the race was over that I forgot to press 'stop' on my Garmin ; also, it recorded only 10.51km (with the missing 500 meters all occurring in the last 2 km, I wonder what's up with these inconsistent numbers?). The final descent was so long that I managed to do kilometres 9 and 10 (according to the Garmin) at 4:34 each, which is something I definitely can't sustain (for 2km) on flat land. Speaking of the group run, it was nice that from about the 6th km until the end I have run in the same mini-group with two other people; it was helpful to have someone to follow/help you keep the pace (even though I finished last of this mini-group, ha!). This time I also had the heartbeat sensor, and I found out that I averaged about ~13 more bpm than in my training (flat) runs. So that's what running alongside other people does: it makes you push yourself (much) harder. On the cadence part, I was again averaging ~82 (times two), and for the last ~5 minutes I was running constantly at 83. Did I mention I like stats? One thing that surprised me on this hilly race was that most people kept about the same speed on downhill as on the flat parts; I wonder why, for me it seemed easy to go much faster (within the same heart rate). It is harder on the knees, so you have to be careful on how you set the foot down, but not that much that I would keep the same speed. Hmm And speaking of hilly races: one of the brochures I saw at the race was about this race: Glacier 3000 run, a 26km run with a nice 1,900 meters of gained altitude (starts at 1,050m and finishes at 2,950m). Basically, up, up and more up. Nice, but one would have to be quite crazy That's all, thanks for reading!