On the last weekend my team and I participated in the Mobile App Camp (link in Lithuanian) organized by Omnitel, which is one of the dominant mobile operators in Lithuania. The event seems to be part of Omnitel's push for increasing the share of smartphones in the Lithuanian market, which has been lagging behind the European trends.

Our team consisted of Povilas Kytra, who is behind the TV.LT project, Mantas Kanaporis from A-Gain and me. In the weekend we built an app that shows the TV programme for the coming day for all the Lithuanian TV channels. (The app is not yet available on the Android Market, but we are working on it.)

Here's a screenshot of the main screen of the application:

It's them, I promise. My camera may have been drinking Maker's Manhattans when I wasn't looking. It was an awesome show -- they played all material from their new album, Never Stop. I agree with the Guardian comment about them -- "If the Coen Brothers put together a jazz trio, perhaps it would be like this..." On Saturday I also saw Bela Fleck and the Flecktones there. I don't have a crappy picture to show for it, but it was a great performance -- which included the 12 Days of Christmas performed in 12 keys and 12 time signatures (or so they claimed, I am in no position to verify that) and the surprise (to me) appearance of Alash, the Siberian throat singers.

Before I discovered you could just point your browser at http://search.cpan.org/meta/Dist-Name-0.007/META.json to automagically convert META.yml and META.json, I wrote a script to do it.
Anyway, it goes with my "I hate the cloud" prejudices :).

use CPAN::Meta;
use CPAN::Meta::Converter;
use Data::Dumper;
my $meta = CPAN::Meta->load_file("META.yml");
my $cmc = CPAN::Meta::Converter->new($meta);
my $new=CPAN::Meta->new($cmc->convert(version=>"2"));
$new->save("META.json");

If you want to provide a wiki but want to leave the authentication to one or more external identity providers, like an identity federation, Dokuwiki and simpleSAMLphp are a good combination. However, the existing documentation is lagging behind on developments in these software packages (i.e. doesn't work anymore), so here's what worked for me. Ingredients:

A Debian 5.0 Lenny system.

Dokuwiki Debian Lenny package (0.0.20080505-4+lenny1).

simpleSAMLphp Debian squeeze package (1.6.2-1).

SSP is not available in Lenny yet but the package from Squeeze installs cleanly on Lenny.

simpleSAMLdokuwiki integration package.

Note that I'm linking to a bug report - you need the file version included in the bottom of that bug report, because the released versions are outdated.

I assume you have read the Dokuwiki and simpleSAMLphp documentation for information on how to install and configure either one; this article purely focuses on the integration part; not on e.g. how to connect an IdP to simpleSAMLphp.

• Install the Debian packages and make sure they work; dokuwiki is accessible and simpleSAMLphp is accessible and configured for your IdP. The simpleSAMLphp website is a good resource for this.
• Put the simplesamlphp.auth.class downloaded from the bug report somewhere on the system, e.g. /opt/simplesamldokuwiki
• Enable the authentication class:

  cd /usr/share/dokuwiki/inc/auth && ln -s /opt/simplesamldokuwiki/simplesamlphp.auth.class

• Add the following to /etc/dokuwiki/local.php (tune attribute names, add more Dokuwiki settings as desired of course):

  $conf['authtype'] = 'simplesamlphp';
  $conf['simplesamlphp_path'] = '/usr/share/simplesamlphp';
  $conf['simplesamlphp_attr_user']     = 'urn:mace:dir:attribute-def:eduPersonPrincipalName';
  $conf['simplesamlphp_attr_name']     = 'urn:mace:dir:attribute-def:cn';
  $conf['simplesamlphp_attr_mail']     = 'urn:mace:dir:attribute-def:mail';
  $conf['simplesamlphp_attr_grps']     = 'groups';
  

• In /etc/simplesamlphp/config.php, set the following so they can share a cookie:

          'session.phpsession.cookiename'  => 'DokuWiki'
  

I also provided a patch to the simplesamldokuwiki class cited above to enable the IdP to not pass a 'mail' attribute: see bug report.

LWN has an article by Valerie Aurora titled The dark side of open source conferences [1] which is about sexual harassment and sexual assault at Free Software conferences. Apparently some conferences create such a bad environment that some people won t attend, it s a well researched article that everyone in the community should read.The Autism DerailmentThe comments have the usual mix of insight, foolishness, and derailment that you expect from such discussions. One derailment thread that annoyed me is the discussion about men on the Autism Spectrum started by Joe Buck [2]. Joe seems to believe that the 1% of males on the Autism Spectrum (and something greater than 1% but a lot less than 50% in the Free Software community) are a serious part of the problem because they supposedly hit on women who aren t interested in them in spite of the fact that the article in question is about women who are being insulted, harassed, and groped at at open source conferences . The article had no mention of men who try to chat up women presumably this was a deliberate decision to focus on sexual assault and harassment rather than what Joe wanted to talk about.In response Mackenzie made the following insightful point:I don t think any autistic person who is high-functioning enough to A) contribute to open source B) want to be at an event with so many people and C) carry on any sort of conversation is low-functioning enough not to understand stop or no. If you can understand your patch has been rejected, you can likely understand don t do that again. Understanding how Other People FeelBruce Perens claimed What they [Aspies] don t understand is how the other person in the situation feels . Like many (possibly most) people Bruce doesn t seem to get the fact that no-one can really understand how other people feel. The best logical analysis of this seems to be the Changing Emotions article on Less Wrong [3]. While Less Wrong deals with Male to Female conversion as the example (which may be relevant to the discussion about the treatment of women) the same logic also applies to smaller changes. Anyone who even thinks that if they would always be able understand how their identical twin felt (if they had one) probably hasn t considered these issues much. As an aside, having a psychologist diagnose you as being on the Autism Spectrum and therefore by implication thinking differently to 99% of the population really makes you consider the ways in which other people might have different thought processes and experiences.Every time we have a discussion about issues related to sexism in the Free Software community we get a lot of documented evidence that there are many people who are apparently neuro-typical (IE not Autistic) who don t understand how other people think in many cases they go so far as to tell other people what their emotional state should be.What Really HappensNix said However, in that situation our natural reflex is to *get out of there*, not to jump on women like some sort of slobbering caveman which is a really good summary.In more detail, I think that the vast majority of guys who are on the Autism Spectrum and who are able to do things like attend computer conferences (*) realise that chatting up a random girl that they meet is something that just isn t going to work out. Generally people don t attempt things that they expect to fail so I don t think that Autistic guys are going to be hitting on girls at conferences.(*) Having never met any Autistic people who aren t capable of attending such conferences I can t speak for them. I really doubt that the Low Functioning Autistic guys are as much of a problem as some people claim, but lack evidence. In any case the actions of people who don t attend conferences aren t relevant to a discussion about things that happen at conferences.Update: It Keeps GoingDion claims that the misogyny at conferences is due to socially inept people, he also casually switches between discussing people who misunderstand when someone is flirting and people who hire almost-naked booth-babes (two very different classes of action) [4]. Several people asked for supporting evidence, naturally none was provided.In response njs posted a link to Marissa Lingen s blog post Don t blame autism, dammit [5]. Marissa points out that people who offend other people due to lacking social skills will tend to do so in times and places that are likely to get a bad reaction if you don t know that you are doing something wrong then there s no reason to hide it. If someone offends a senior manager at a corporate event then it could be because they are on the Autism Spectrum (I ve apparently done that). If someone offends junior people at a times and places where there are no witnesses but is always nice to managers and other powerful people then it s not related to Autism.One final note, I have little tolerance for anyone who claims to be an Aspie when they do something wrong. You are either on the Autism Spectrum all the time or none of it. Anyone who wants any sympathy for me for an occasion where they stuffed up due to being an Aspie can start by making a clear statement about where they are on the Autism Spectrum.Update2: Yet More from Bruce PerensBruce wrote IMO, the kind of men who go in to software engineering suffer a lack of healthy interaction with women who are their peers, and it may be that the high incidence of empathy disorders in our field is involved (which seems to be part of the inspiration for Joe Buck later in that thread) and now claims Nobody here was trying to connect Asperger s or autism with the touching incidents or violent crime .Matthew Garrett responded to that with If you weren t trying to say that the high incidence of empathy disorders in our field was related to a lack of healthy interaction with women who are their peers, and that that has something to do with incidents of sexual harassment or assault at conferences, what were you trying to say? Because that sounds awfully like We wouldn t have so many problems if it weren t for all the autists .Bruce s latest comment is If you choose to read something that nasty into my writing, that s your problem. Get therapy .Through this discussion I ve been unsure of whether to interpret the statements by Bruce et al the way Matthew does or whether I should consider them as merely a desperate attempt to derail the discussion. I can t imagine any possible way of interpreting such comments in connection with the discussion of sexual assault as anything other than either trivialising violent crimes against women (suggesting that they are no worse than asking out someone who s not interested) or claiming that anyone who lacks social skills should be treated as a violent sexual predator. It s just not reasonable to believe that every single person who wrote such comments referring to Autism was misunderstood and really meant something nice.As a general rule I don t think that it s the responsibility of other people to try and find a non-offensive interpretation of something that one might say. I don t think that all the people who strongly disagree with the most obvious and reasonable interpretations of Bruce s comments should get therapy. I think that Bruce should explain what he means clearly.

• [1] http://lwn.net/Articles/417952/
• [2] http://lwn.net/Articles/418209/
• [3] http://lesswrong.com/lw/xe/changing_emotions/
• [4] http://lwn.net/Articles/418281/
• [5] http://mrissa.livejournal.com/746160.html

If you have been following this blog during the past months, you might have gathered that I ve been focusing on I/O patterns on library initialization, more specifically libxul.so. The very patterns there s not much to do about, except enduring them, or hacking ld.so and/or the toolchain. The latter is not necessarily easy, and won t benefit everyone until all linux distros use an improved glibc and/or toolchain. This could take years before any actual result would reach end users. But with a little creativity, one can overcome these limitations and improve the situation today. Here is a summary of my recent hacks. Backwards static initializers As Taras showed in the past, static initializers are executed in reverse order. It turns out it is an unfortunate design choice in gcc, and it also turns out not to impact all ELF binary files. As far as I know there are currently two different implementations of the static initializers call loop, one provided by gcc, and one provided by ld.so. In the gcc case, the compiler creates a .ctors section, starting with 0xffffffff, ending with 0x00000000, and filled with pointers to the various static initializer functions, in ascending order. The compiler also injects an initializer function, called from .init, going through this .ctors section, starting from the end (__do_global_ctors_aux in crtend.o). A similar .dtors section is created for functions to run when the library is unloaded, and the pointers in it are called in ascending order. There is actually no importance in the order in which .ctors and .dtors are executed. All that matters is that they are executed in reverse order from each other, because that limits the risks of bad ordering. It is only unfortunate that .ctors was chosen to be the one backwards. In the ld.so case, the compiler creates a .init_array section, filled with pointers to the various static initializer functions, in ascending order. It also stores the location and the size of this section in the PT_DYNAMIC ELF header. At runtime, ld.so itself reads this information and executes the static initializers in ascending orders. A similar .fini_array section is created for functions to run when the library in unloaded, and ld.so goes through it in descending order. The .init_array section is newer, and for backwards compatibility reasons, is not used on systems that have been using the .ctors approach forever. On the other hand, some newer ABIs, such as arm EABI, uses the new facility, which means they are not victim of backwards static initialization. I however wonder if backwards compatibility is still needed, considering how long .init_array support has been around (more than 11 years, according to glibc git repository). While we could obviously bug the gcc maintainers to revert their .ctors execution order, or ditch .ctors support on glibc systems, which means we wouldn t get any immediate global benefit, we can also just revert the .ctors section content. Please note the source code out there doesn t take care of reverting the .dtors section accordingly, because it is currently empty in libxul.so. Relocations As I mentioned in an earlier post, relocations are what make it possible to load libraries at arbitrary locations. Unfortunately, a great number of relocations means awful I/O patterns: ld.so reads and applies them one by one, and while the kernel reads ahead by 128 KB chunks, when your relocation section exceeds that amount by more than an order of magnitude, it means I/O goes back and forth a lot between the relocation section and where the relocations take place. There are two classes of relocations: REL and RELA. In both cases, there are several types of relocations, some of which require an addend. The difference between both classes is in REL relocations, the addend is stored at the offset the relocation takes place, and in RELA relocations, the addend is stored in the relocation entry. It means that RELA relocations effectively waste space, as the addend ends up actually being stored twice: it is also stored at the offset the relocation takes place, like with REL relocations, though it could technically be nulled out, there ; in any case, the space is wasted. REL relocations thus take 2 words of storage, and RELA relocations, 3. On x86, the ELF ABI only uses REL relocations, and words are 32 bits, making each relocation take 8 bytes ; on x86-64, the ELF ABI only uses RELA relocations, and words are 64 bits, thus making each relocation take 24 bytes, 3 times that of x86 relocations. On ARM, both may be used, but apparently the compiler and the linker only use REL relocations. These words of storage are used to store 3 or 4 bits of informations:

• r_offset: the offset at which the relocation takes place
• r_info: containing both the relocation type and a symbol reference for the relocation. On 32 bits systems, the symbol reference is stored on 24 bits, and the relocation type on 8 bits. On 64 bits systems, the symbol reference is stored on 32 bits, and the relocation type on 32 bits (which means at least 24 bits are never going to be used: there are currently no ABI using more than 256 relocation types).
• r_addend: The addend, only in RELA relocations

The linker splits relocations in two main categories: those for dynamic linking at startup and those for procedure linkage table (PLT) resolution at runtime. Here is what the repartition look like on libxul.so (taken from the mozilla-central nightly from Nov, the 22nd):

	dynamic relocations		PLT relocations
Architecture	number	size (bytes)	number	size (bytes)
x86	231,836	1,854,688	3,772	30,176
x86-64	235,893	5,661,432	3,773	90,528

So, PLT relocations are quite negligible, and dynamic relocations are just huge, especially on x86-64. Compared to the binary size, it s pretty scary:

Architecture	libxul.so size	relocations size	%
x86	21,869,684	1,884,864	8.61%
x86-64	29,629,040	5,751,984	19.41%

Let me remind you that not only do we need to read these relocations at startup (at least the dynamic ones, but the PLT ones are just negligible), but we only read them by chunks, and need to read other data in between. Of the many existing types of relocations, only a few are actually used in dynamic libraries. Here is a summary of those in use in libxul.so:

x86 relocation type	number	x86-64 relocation type	number
dynamic relocations
R_386_TLS_DTPMOD32	1	R_X86_64_DTPMOD64	1
R_386_GLOB_DAT	213	R_X86_64_GLOB_DAT	238
R_386_32	27,643	R_X86_64_64	27,611
R_386_RELATIVE	203,979	R_X86_64_RELATIVE	208,043
PLT relocations
R_386_JUMP_SLOT	3,772	R_X86_64_JUMP_SLOT	3,773

The above types can be separated in two distinct categories:

• Requiring symbols resolution (R_*_GLOB_DAT, R_*_JUMP_SLOT, R_386_32, R_X86_64_64)
• Not requiring symbols resolution (R_*_RELATIVE, R_386_TLS_DTPMOD32, R_X86_64_TLS_DTPMOD64)

In the second category, it means we are wasting all the bits for the symbol reference in each entry: 24 on x86 and 32 on x86-64. Unfortunately, the vast majority of the relocations in libxul.so are from that category. At this point, this is how much waste we identified:

description	num. entries	waste per entry (bytes)	total	% of relocation size
x86
Relocation without symbol ref.	203,980	3	611,937	32.46%
x86-64
Duplicated addend	239,666	8	1,917,328	33.33%
Relocation type encoded on 32 bits	239,666	3	718,998	12.49%
Relocation without symbol ref.	208,044	4	832,176	14.46%
Total			3,468,502	60.30%

On top of that, one could argue that we don t need 24 or 32 bits for symbol reference (which is the entry number in the symbol table), and that we re really far from requiring 64 bits for r_offset on 64 bits systems, as libxul.so is far from being bigger than 4GB. Anyways, that means we have room for improvement here, and it means that the ELF format, especially on 64 bits systems with RELA relocations, really doesn t help with big programs or libraries with a lot of relocations. (For that matter, the mach-o format used on OS-X has some kind of similar issues ; I don t know for the DLL format) Another interesting data point is looking at how relocations r_offset are following each other, once relocations are reordered (to avoid too much symbol resolution, they are actually grouped by symbol). It turns out 206,739 relocations r_offset are at 4 bytes from the previous one on x86 (i.e. strictly following it), and 210,364 at 8 bytes from the previous on x86-64. The main reason why this happens is that most relocations are happening in pointer tables, and libxul.so has lots of them:

• That s what you get with virtual methods in C++.
• That s also what you get in .ctors and .dtors sections, which are relocated as well (but not .init_array and .fini_array sections).
• That s what you get when you use function tables.
• Obvously, that s what you get when you use pointer tables.

And when I say libxul.so has lots of them, that s not an understatement: there are 184,320 relocations due to vtables (function tables you get when using virtual methods in C++) on x86 and 184,098 on x86-64. That s respectively 78.23% and 76.81% of the total number of relocations. Interestingly, while most of these relocations are R_*_RELATIVE, 26,853 are R_386_32, and 26,829 are R_X86_64_64. Except for a very few, these non relative relocations are for the __cxa_pure_virtual symbol, which is a dummy function that does nothing, used for pure virtual methods, such as the following:

class Abstract
public:
virtual void pure_virtual() = 0;
;

As for the remaining relative relocations, there are a few pointer tables responsible for several thousand relocations, such as JSString::length2StringTable, gEntries, GkAtoms_info, Html5Atoms_info, kUnixCharsets, nsIDOMCSS2Properties_properties, etc. Packing relocations While they are not detrimental to most binaries, we saw that relocations can have a bad effect on startup I/O for big binaries. Reducing how much space they take would have a direct impact on these startup I/Os. One way to do so is obviously to reduce the number of relocations. But as we saw above, the vast majority are due to vtables. While reducing vtables would be a nice goal, it s a long way before this can have a significant impact on the relocations number. So another possible way is to try to avoid wasting so much space in relocations. The main problem is that relocations are applied by ld.so, and that, as mentioned in the introduction, while we can hack ld.so to do what we want, it won t work everywhere before a long time. Moreover, it s difficult to test various implementations, and binary compatibility needs to be guaranteed once something is applied in the upstream libc. The idea I started to test a few weeks ago, is to effectively apply relocations by hand instead of relying on ld.so doing it. Considering the first thing ld.so does with a library after applying relocations is to call its DT_INIT function, the idea was to replace the dynamic relocations we can with a new DT_INIT function we would inject that d apply those relocations, while storing them in a more efficient manner. The function would obviously need to call the original DT_INIT function once done. Some parts of the PT_DYNAMIC section also obviously need to be adjusted accordingly. The first iteration I tested a few weeks ago helped validating the idea, but didn t change much of the binary: the dynamic relocation section still was taking all the space it took before, though its content was mostly empty (we ll see further below how efficient even the current dumb format is). Once the theory that an injected DT_INIT function could apply the relocations without breaking everything, I went on to implement a program that would actually strip the ELF binary. I won t get too much into the gory details, but it required PT_LOAD splitting, thus program headers growth, which means moving the following sections, then removing a huge part of the relocations, shrinking the relocations section, injecting our code and the packed relocations as sections, and moving the remaining sections after these new sections, to avoid empty space, but still respecting the proper offsets for both PT_LOAD and the code itself. So far, I only took care of the R_*_RELATIVE relocations. Some but not all other relocations could be taken care of, too, but everything involving symbol resolution from other libraries would be really difficult to handle from the injected code. The relocations are currently stored with a quite dumb format:

• a 32 bits word containing r_offset
• a 32 bits word containing the number of relocations to apply consecutively

As we only take care of one type of relocations, we can skip any information about the type. Also, the addend already being stored at r_offset, we just strip it from RELA relocations ; the binary being far from 4GB big, 32 bits is enough on 64 bits systems too. We also saw that a lot of relocations were next to the following ones, so instead of storing r_offset for each one, storing some kind of range is more efficient. As I ve so far been focusing on getting something that actually works more than on getting something really efficient, I only tested this format, but the results are already nice:

	x86	x86-64
before
dynamic relocations (bytes)	1,854,688	5,661,432
libxul.so size	21,869,684	29,629,040
after
dynamic relocations (bytes)	222,856	668,400
injected code size	129	84
packed relative relocations (bytes)	224,816	228,568
libxul.so size	20,464,836 (-6.42%)	24,865,520 (-16.07%)

Getting rid of the __cxa_pure_virtual relocations would help getting this even further down, and an even better storage format could be used, too. Gathering new startup coverage data should be interesting as well. The code is available via mercurial. Please note the Makefile deeply sucks, and that the code is in the middle of its third refactoring. Anyways, once you get the code to compile, you just need to run test-x86 or test-x64 depending on your architecture, from the build directory, and give it the libxul.so file as an argument. It will create a libxul.so.new file that you can use to replace libxul.so. You may successfully use the tool on other libraries, but chances are you ll bump into an assert(), or in the worst case, that the resulting library ends up broken. The tool might work on PIE executables, but most probably not on other executables. If you wonder, Chrome is not PIE. It s not even relocatable (which means ASLR won t work with it) ; or at least the x86-64 binaries I just got aren t. More possible ELF hacking The code I wrote to pack relocations allows to do various tricks on ELF files, and it opens various opportunities, such as:

• Aligning .bss. As I wrote on this blog a while ago, ld.so fills the last page from the .data section with zeroes, starting at the offset of the .bss section. Unfortunately, this means reading ahead at most 128KB of data nobody needs, and the corresponding disk seek. Inserting a section full of zeroes between .data and .bss would get rid of that, while minimally wasting space (less than 4KB in a 20MB+ binary).
• Trying to move the PT_DYNAMIC section. It is one of the first bunch of data to be read from programs and libraries, yet it is near the end of the binary.
• Replacing .ctors/.dtors with .init_array/.fini_array (thus removing the corresponding relocations, though there s only around 300 of them).
• Replacing the __cxa_pure_virtual relocations with relative relocations pointing to an injected dummy function (it could even just point to any ret code in any existing function).
• Replacing some internal symbol resolutions with relative relocations (which should be equivalent to building with -Bsymbolic)
• etc.

Some of the above could probably be done with linker scripts, but using linker scripts is unnecessarily over complicated: as soon as you start using a linker script to fiddle with sections, you need to reimplement the entire default linker script (the one you can see with ld --verbose). And it s not guaranteed to work (Taras told me he had a hard time failing to align the .bss section). And as far as I know, you can t use the same thing depending whether you use ld or gold (AIUI, gold doesn t support the whole ld linker script syntax).

I'm still running upgrade testing of the Lenny Gnome and KDE Desktop, but have not had time to spend on reporting the status. Here is a short update based on a test I ran 20101118. I still do not know what a correct migration should look like, so I report any differences between apt and aptitude and hope someone else can see if anything should be changed. This is for Gnome: Installed using apt-get, missing with aptitude

apache2.2-bin aptdaemon at-spi baobab binfmt-support browser-plugin-gnash cheese-common cli-common cpp-4.3 cups-pk-helper dmz-cursor-theme empathy empathy-common finger freedesktop-sound-theme freeglut3 gconf-defaults-service gdm-themes gedit-plugins geoclue geoclue-hostip geoclue-localnet geoclue-manual geoclue-yahoo gnash gnash-common gnome gnome-backgrounds gnome-cards-data gnome-codec-install gnome-core gnome-desktop-environment gnome-disk-utility gnome-screenshot gnome-search-tool gnome-session-canberra gnome-spell gnome-system-log gnome-themes-extras gnome-themes-more gnome-user-share gs-common gstreamer0.10-fluendo-mp3 gstreamer0.10-tools gtk2-engines gtk2-engines-pixbuf gtk2-engines-smooth hal-info hamster-applet libapache2-mod-dnssd libapr1 libaprutil1 libaprutil1-dbd-sqlite3 libaprutil1-ldap libart2.0-cil libatspi1.0-0 libboost-date-time1.42.0 libboost-python1.42.0 libboost-thread1.42.0 libchamplain-0.4-0 libchamplain-gtk-0.4-0 libcheese-gtk18 libclutter-gtk-0.10-0 libcryptui0 libcupsys2 libdiscid0 libeel2-data libelf1 libepc-1.0-2 libepc-common libepc-ui-1.0-2 libfreerdp-plugins-standard libfreerdp0 libgail-common libgconf2.0-cil libgdata-common libgdata7 libgdl-1-common libgdu-gtk0 libgee2 libgeoclue0 libgexiv2-0 libgif4 libglade2.0-cil libglib2.0-cil libgmime2.4-cil libgnome-vfs2.0-cil libgnome2.24-cil libgnomepanel2.24-cil libgnomeprint2.2-data libgnomeprintui2.2-common libgnomevfs2-bin libgpod-common libgpod4 libgtk2.0-cil libgtkglext1 libgtksourceview-common libgtksourceview2.0-common libmono-addins-gui0.2-cil libmono-addins0.2-cil libmono-cairo2.0-cil libmono-corlib2.0-cil libmono-i18n-west2.0-cil libmono-posix2.0-cil libmono-security2.0-cil libmono-sharpzip2.84-cil libmono-system2.0-cil libmtp8 libmusicbrainz3-6 libndesk-dbus-glib1.0-cil libndesk-dbus1.0-cil libopal3.6.8 libpolkit-gtk-1-0 libpt-1.10.10-plugins-alsa libpt-1.10.10-plugins-v4l libpt2.6.7 libpython2.6 librpm1 librpmio1 libsdl1.2debian libservlet2.4-java libsrtp0 libssh-4 libtelepathy-farsight0 libtelepathy-glib0 libtidy-0.99-0 libxalan2-java libxerces2-java media-player-info mesa-utils mono-2.0-gac mono-gac mono-runtime nautilus-sendto nautilus-sendto-empathy openoffice.org-writer2latex openssl-blacklist p7zip p7zip-full pkg-config python-4suite-xml python-aptdaemon python-aptdaemon-gtk python-axiom python-beautifulsoup python-bugbuddy python-clientform python-coherence python-configobj python-crypto python-cupshelpers python-cupsutils python-eggtrayicon python-elementtree python-epsilon python-evolution python-feedparser python-gdata python-gdbm python-gst0.10 python-gtkglext1 python-gtkmozembed python-gtksourceview2 python-httplib2 python-louie python-mako python-markupsafe python-mechanize python-nevow python-notify python-opengl python-openssl python-pam python-pkg-resources python-pyasn1 python-pysqlite2 python-rdflib python-serial python-tagpy python-twisted-bin python-twisted-conch python-twisted-core python-twisted-web python-utidylib python-webkit python-xdg python-zope.interface remmina remmina-plugin-data remmina-plugin-rdp remmina-plugin-vnc rhythmbox-plugin-cdrecorder rhythmbox-plugins rpm-common rpm2cpio seahorse-plugins shotwell software-center svgalibg1 system-config-printer-udev telepathy-gabble telepathy-mission-control-5 telepathy-salut tomboy totem totem-coherence totem-mozilla totem-plugins transmission-common xdg-user-dirs xdg-user-dirs-gtk xserver-xephyr zip

Installed using apt-get, removed with aptitude

arj bluez-utils cheese dhcdbd djvulibre-desktop ekiga eog epiphany-extensions epiphany-gecko evolution-exchange fast-user-switch-applet file-roller gcalctool gconf-editor gdm gedit gedit-common gnome-app-install gnome-games gnome-games-data gnome-nettool gnome-system-tools gnome-themes gnome-utils gnome-vfs-obexftp gnome-volume-manager gnuchess gucharmap guile-1.8-libs hal libavahi-compat-libdnssd1 libavahi-core5 libavahi-ui0 libbind9-50 libbluetooth2 libcamel1.2-11 libcdio7 libcucul0 libcurl3 libdirectfb-1.0-0 libdmx1 libdvdread3 libedata-cal1.2-6 libedataserver1.2-9 libeel2-2.20 libepc-1.0-1 libepc-ui-1.0-1 libexchange-storage1.2-3 libfaad0 libgadu3 libgalago3 libgd2-noxpm libgda3-3 libgda3-common libggz2 libggzcore9 libggzmod4 libgksu1.2-0 libgksuui1.0-1 libgmyth0 libgnome-desktop-2 libgnome-pilot2 libgnomecups1.0-1 libgnomeprint2.2-0 libgnomeprintui2.2-0 libgpod3 libgraphviz4 libgtk-vnc-1.0-0 libgtkhtml2-0 libgtksourceview1.0-0 libgtksourceview2.0-0 libgucharmap6 libhesiod0 libicu38 libisccc50 libisccfg50 libiw29 libjaxp1.3-java-gcj libkpathsea4 liblircclient0 libltdl3 liblwres50 libmagick++10 libmagick10 libmalaga7 libmozjs1d libmpfr1ldbl libmtp7 libmysqlclient15off libnautilus-burn4 libneon27 libnm-glib0 libnm-util0 libopal-2.2 libosp5 libparted1.8-10 libpisock9 libpisync1 libpoppler-glib3 libpoppler3 libpt-1.10.10 libraw1394-8 libsdl1.2debian-alsa libsensors3 libsexy2 libsmbios2 libsoup2.2-8 libspeexdsp1 libssh2-1 libsuitesparse-3.1.0 libsvga1 libswfdec-0.6-90 libtalloc1 libtotem-plparser10 libtrackerclient0 libvoikko1 libxalan2-java-gcj libxerces2-java-gcj libxklavier12 libxtrap6 libxxf86misc1 libzephyr3 mysql-common rhythmbox seahorse sound-juicer swfdec-gnome system-config-printer totem-common totem-gstreamer transmission-gtk vinagre vino w3c-dtd-xhtml wodim

Installed using aptitude, missing with apt-get

gstreamer0.10-gnomevfs

Installed using aptitude, removed with apt-get

[nothing]

This is for KDE: Installed using apt-get, missing with aptitude

autopoint bomber bovo cantor cantor-backend-kalgebra cpp-4.3 dcoprss edict espeak espeak-data eyesapplet fifteenapplet finger gettext ghostscript-x git gnome-audio gnugo granatier gs-common gstreamer0.10-pulseaudio indi kaddressbook-plugins kalgebra kalzium-data kanjidic kapman kate-plugins kblocks kbreakout kbstate kde-icons-mono kdeaccessibility kdeaddons-kfile-plugins kdeadmin-kfile-plugins kdeartwork-misc kdeartwork-theme-window kdeedu kdeedu-data kdeedu-kvtml-data kdegames kdegames-card-data kdegames-mahjongg-data kdegraphics-kfile-plugins kdelirc kdemultimedia-kfile-plugins kdenetwork-kfile-plugins kdepim-kfile-plugins kdepim-kio-plugins kdessh kdetoys kdewebdev kdiamond kdnssd kfilereplace kfourinline kgeography-data kigo killbots kiriki klettres-data kmoon kmrml knewsticker-scripts kollision kpf krosspython ksirk ksmserver ksquares kstars-data ksudoku kubrick kweather libasound2-plugins libboost-python1.42.0 libcfitsio3 libconvert-binhex-perl libcrypt-ssleay-perl libdb4.6++ libdjvulibre-text libdotconf1.0 liberror-perl libespeak1 libfinance-quote-perl libgail-common libgsl0ldbl libhtml-parser-perl libhtml-tableextract-perl libhtml-tagset-perl libhtml-tree-perl libio-stringy-perl libkdeedu4 libkdegames5 libkiten4 libkpathsea5 libkrossui4 libmailtools-perl libmime-tools-perl libnews-nntpclient-perl libopenbabel3 libportaudio2 libpulse-browse0 libservlet2.4-java libspeechd2 libtiff-tools libtimedate-perl libunistring0 liburi-perl libwww-perl libxalan2-java libxerces2-java lirc luatex marble networkstatus noatun-plugins openoffice.org-writer2latex palapeli palapeli-data parley parley-data poster psutils pulseaudio pulseaudio-esound-compat pulseaudio-module-x11 pulseaudio-utils quanta-data rocs rsync speech-dispatcher step svgalibg1 texlive-binaries texlive-luatex ttf-sazanami-gothic

Installed using apt-get, removed with aptitude

amor artsbuilder atlantik atlantikdesigner blinken bluez-utils cvs dhcdbd djvulibre-desktop imlib-base imlib11 kalzium kanagram kandy kasteroids katomic kbackgammon kbattleship kblackbox kbounce kbruch kcron kdat kdemultimedia-kappfinder-data kdeprint kdict kdvi kedit keduca kenolaba kfax kfaxview kfouleggs kgeography kghostview kgoldrunner khangman khexedit kiconedit kig kimagemapeditor kitchensync kiten kjumpingcube klatin klettres klickety klines klinkstatus kmag kmahjongg kmailcvt kmenuedit kmid kmilo kmines kmousetool kmouth kmplot knetwalk kodo kolf kommander konquest kooka kpager kpat kpdf kpercentage kpilot kpoker kpovmodeler krec kregexpeditor kreversi ksame ksayit kshisen ksig ksim ksirc ksirtet ksmiletris ksnake ksokoban kspaceduel kstars ksvg ksysv kteatime ktip ktnef ktouch ktron kttsd ktuberling kturtle ktux kuickshow kverbos kview kviewshell kvoctrain kwifimanager kwin kwin4 kwordquiz kworldclock kxsldbg libakode2 libarts1-akode libarts1-audiofile libarts1-mpeglib libarts1-xine libavahi-compat-libdnssd1 libavahi-core5 libavc1394-0 libbind9-50 libbluetooth2 libboost-python1.34.1 libcucul0 libcurl3 libcvsservice0 libdirectfb-1.0-0 libdjvulibre21 libdvdread3 libfaad0 libfreebob0 libgd2-noxpm libgraphviz4 libgsmme1c2a libgtkhtml2-0 libicu38 libiec61883-0 libindex0 libisccc50 libisccfg50 libiw29 libjaxp1.3-java-gcj libk3b3 libkcal2b libkcddb1 libkdeedu3 libkdegames1 libkdepim1a libkgantt0 libkleopatra1 libkmime2 libkpathsea4 libkpimexchange1 libkpimidentities1 libkscan1 libksieve0 libktnef1 liblockdev1 libltdl3 liblwres50 libmagick10 libmimelib1c2a libmodplug0c2 libmozjs1d libmpcdec3 libmpfr1ldbl libneon27 libnm-util0 libopensync0 libpisock9 libpoppler-glib3 libpoppler-qt2 libpoppler3 libraw1394-8 librss1 libsensors3 libsmbios2 libssh2-1 libsuitesparse-3.1.0 libswfdec-0.6-90 libtalloc1 libxalan2-java-gcj libxerces2-java-gcj libxtrap6 lskat mpeglib network-manager-kde noatun pmount tex-common texlive-base texlive-common texlive-doc-base texlive-fonts-recommended tidy ttf-dustin ttf-kochi-gothic ttf-sjfonts

Installed using aptitude, missing with apt-get

dolphin kde-core kde-plasma-desktop kde-standard kde-window-manager kdeartwork kdebase kdebase-apps kdebase-workspace kdebase-workspace-bin kdebase-workspace-data kdeutils kscreensaver kscreensaver-xsavers libgle3 libkonq5 libkonq5-templates libnetpbm10 netpbm plasma-widget-folderview plasma-widget-networkmanagement xscreensaver-data-extra xscreensaver-gl xscreensaver-gl-extra xscreensaver-screensaver-bsod

Installed using aptitude, removed with apt-get

kdebase-bin konq-plugins konqueror

<script type="text/javascript"> var flattr_wp_ver = '0.9.11'; var flattr_uid = '34168'; var flattr_url = 'http://www.sourceguru.net/bad-tech-support-feel/'; var flattr_btn = 'compact'; var flattr_hide = 0; var flattr_lng = 'en_GB'; var flattr_cat = 'text'; var flattr_tle = 'How bad tech support makes me feel'; var flattr_dsc = ''; var flattr_tag = 'punch,stabby,tech support'; </script> <script src="http://api.flattr.com/button/load.js?v=0.2" type="text/javascript"></script>

A few months after starting the NM process, I have just been accepted as a Debian Developer. My account name is simply: julien I have been a Debian user for about 10 years now, and have begun contributing to Debian in 2005. I have then been accepted as a Debian Maintainer in 2007. This post is mainly to thank:

• all my sponsors: Christoph Haas (haas) , Lo c Minier (lool), Free Ekanayaka (freee), Maximiliano Curia (maxy) and Micah Anderson (micah),
• my advocate: Matthijs M hlman (matthijs)
• my AM (who actually make it happen in a really short time frame, thanks a lot to him): Xavier Oswald (xoswald)
• all people who helped me during the process, to name a few: Christoph Berg (myon), Enrio Zini (enrico), Peter Palfrader (weasel)

Also thanks to all people who have already sent their congratulations, it makes me very proud!

So, I m (almost) back from the first edition of MiniDebConf Paris, which was a success thanks to the great organizing skills in panic mode of Carl Chenet and Mehdi Dogguy. I think that everybody is already looking forward to the next edition. I met lots of people, and it was great to be able to finally put faces on names from the french free software community. I gave two talk there, the first one on Debian and Ubuntu (slides), the second one on Debian Quality Assurance (slides), which both went well (I think). I also hacked a bit:

• I added tags and claimed by to UDD Bugs Search.
• I worked on my piuparts replacement (which really needs a sexy name ; I m open to suggestions), processing the results, making some improvements to the script, and filing 16 RC bugs.

If you want to help me, here are some easy tasks that need takers (it s unlikely that I ll be able to tackle them anytime soon):

• One missing thing in UDD Bugs Search is information about the deferred/delayed queue. Unfortunately, the ftp-masters status information is not available in a machine-parseable format.
  • Improve dak code to also export the data in a machine-parseable format (JSON, YAML). I was told the changes are to be done in dak/show_deferred.py.
  • Write the corresponding UDD importer (actually, that s a 30 mins job for me, so I could easily find time to do it if the data was available).
  Update: done!
• Another missing thing is comments (as on bts.turzimmer.net). I don t really have good ideas about how to implement them, so if you want to tackle that with your own idea, go ahead. (It s probably easy to setup a copy of bugs.cgi on alioth if you are not a DD). The CGI is in Ruby.
• Help me process the logs of my piuparts replacement, and file the bugs. I don t have any good scripts to automate bug filings yet. You need a good understanding of packages dependencies and maintainers scripts, but it s a good way to learn, too. (I would need to regenerate the full results first, so talk to me if you are interested)

One of the other things I d like to do is discuss ways to improve the synchronization of UDD (currently, it s synchronized at arbitrary times, while we could sync Sources+Packages just after dinstall, for example).

I m attending the mini-Debconf Paris and I just gave a talk about the latest improvement of dpkg-dev the package providing the basic tools used to build Debian packages. Latest is a bit stretched since it embraces the last 2-3 years of development. My talk covered the following topics:

• Support of symbols files by dpkg-shlibdeps, dpkg-gensymbols
• Support of new source formats by dpkg-source
• Supplementary options for dpkg-source
• Cross distribution collaboration with dpkg-vendor
• Custom compilation flags with dpkg-buildflags
• Miscellaneous improvements to other tools

The slides are relatively verbose so that you can understand them even if you did not attend the talk. Click here to get the slides. Related links This section points to various articles that cover more extensively some of the features mentioned in my talk. Concerning dpkg-source:

• About new source formats
• How to customize dpkg-source s behaviour in your Debian source package
• How to create Debian packages with alternative compression methods
• How to use multiple upstream tarballs in Debian source packages?
• Managing distribution-specific patches with a common source package

Concerning dpkg-maintscript-helper:

• Correctly renaming a conffile in Debian package maintainer scripts
• The right way to remove an obsolete conffile in a Debian package

Concerning dpkg-vendor:

• How to generate different dependencies on Debian and Ubuntu with a common source package

One comment Support my work

Another month ending and you still have some clicks left on flattr.com? How about these then?

• newsbeuter the mutt of RSS feedreaders
  Newsbeuter is an open-source RSS/Atom feed reader for text terminals. It runs on Linux, FreeBSD, Mac OS X and other Unix-like operating systems. Newsbeuter s great configurability and vast number of features make it a perfect choice for people that need a slick and fast feed reader that can be completely controlled via keyboard.
  I m using newsbeuter as my main rss reader on the PC (but I have to admit, I read more feeds on my Android while traveling and not working at the PC).
• SparkleShare Sharing work made easy
  SparkleShare shines by its absence. Unlike other syncing tools it s designed to get out of your way, to make sharing documents and collaboration easier, and to make peers aware of what you are doing.
  Haven t used it myself yet, but it looks like a superb replacement for Dropbox in the future.
• Gajim
  Gajim is a full featured and easy to use Jabber client. It is available under Linux and Window. Some features it supports: chat, groupchat, bookmarks, file transfer, link-local connection, metacontacts, secure connection, audio / video chat,
  Yes, I use screen+irssi+BitlBee much, but Gajim still deserves love as it is open the whole day too (don t ask me why).
• Mixxx 1.8.1
  Mixxx is free, open source software for performing live DJ mixes. Developed by a diverse community of DJs, Mixxx is a complete replacement for a conventional turntables and mixer DJ setup, and is available for Windows, Mac OS X, and Linux. Mixxx 1.8.0 includes a year s worth of contributions from over 30 developers and artists, and is our most exciting release to date. This release includes much anticipated features such as looping, hot cues, support for multiple MIDI devices, and a brand new database-powered library. Check out the full list of changes on our blog: http://mixxxblog.blogspot.com/2010/10/mixxx-180-released.html Money collected through this Flattr account goes to directly support Mixxx development. Show some love!
  Awesome DJing software for the OpenDJs out there (I m still learning).
• mentors.debian.net Helps you get your packages into Debian
  Only approved members of the Debian project so-called Debian Developers are granted the permission to upload software packages into the Debian distribution. Still a large number of packages is maintained by non-official developers. mentors.debian.net helps them to find a sponsor to get their packages into Debian.
  Yeah, I am DD, but many others are not and mentors.d.n helps them to get their stuff checked and uploaded. Thanks for the time before my key got almighty ;)

Again, all non-italics text is stolen directly from flattr, and please forgive me if I recommend some thing that hasn t been officialy announced yet :)

Number of contributors to gnome-shell code (ie, the js and src directories)	40
Number of contributors to gnome-shell code who work for Red Hat	8
Percentage of gnome-shell code written by Red Hat by lines	91%

Which, I'll admit, does make it look like gnome-shell is controlled by the sinister Red Hat shadowman that rejects external contributions in order to keep a tight reign on the project and prevent Canonical from improving the desktop Linux experience. Let's check Unity.

Number of contributors to Unity code (ie, the unity and unity-priv directories)	10
Number of contributors to Unity code who work for Canonical	10
Percentage of Unity code written by Canonical by lines	100%

Yup, it's a conspiracy.

If you re running a 64bit system, and you ve got users with access to a video device (/dev/video*), then be sure you update your kernels for CVE-2010-2963. I ve been slowly making my way through auditing the many uses in the Linux kernel of the copy_from_user() function, and ran into this vulnerability. Here s the kernel code from drivers/media/video/v4l2-compat-ioctl32.c:

static int get_microcode32(struct video_code *kp, struct video_code32 __user *up)
 
        if (!access_ok(VERIFY_READ, up, sizeof(struct video_code32))  
                copy_from_user(kp->loadwhat, up->loadwhat, sizeof(up->loadwhat))  
                get_user(kp->datasize, &up->datasize)  
                copy_from_user(kp->data, up->data, up->datasize))
                        return -EFAULT;
        return 0;
 

Note that kp->data is being used as the target for up->data in the final copy_from_user() without actually verifying that kp->data is pointing anywhere safe. Here s the caller of get_microcode32:

static long do_video_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 
        union  
                struct video_tuner vt;
                struct video_code vc;
...
          karg;
        void __user *up = compat_ptr(arg);
...
        switch (cmd)  
...
        case VIDIOCSMICROCODE:
                err = get_microcode32(&karg.vc, up);
...

So, the contents of up are totally under control of the caller, and the contents of karg (in our case, the video_code structure) are not initialized at all. So, it seems like a call for VIDIOCSMICROCODE would write video_code->datasize bytes from video_code->data into some random kernel address, just causing an Oops, since we don t control what is on the kernel s stack. But wait, who says we can t control the contents of the kernel s stack? In fact, this compat function makes it extremely easy. Let s look back at the union. Notice the struct video_tuner? That gets populated from the caller s up memory via this case of the switch (cmd) statement:

...
        case VIDIOCSTUNER:
        case VIDIOCGTUNER:
                err = get_video_tuner32(&karg.vt, up);
...

So, to control the kernel stack, we just need to call this ioctl twice in a row: once to populate the stack via VIDIOCSTUNER with the contents we want (including the future address for video_code->data, which starts at the same location as video_tuner->name[20]), and then again with VIDIOCSMICROCODE. Tricks involved here are: the definition of the VIDIOCSMICROCODE case in the kernel is wrong, and calling the ioctls without any preparation can trigger other kernel work (memory faults, etc) that may destroy the stack contents. First, we need the real value for the desired case statement. This turns out to be 0 4020761b. Next, we just repeatedly call the setup ioctl in an attempt to get incidental kernel work out of the way so that our last ioctl doing the stack preparation will stick, and then we call the buggy ioctl to trigger the vulnerability. Since the ioctl already does a multi-byte copy, we can now copy arbitrary lengths of bytes into kernel memory. One method of turning an arbitrary kernel memory write into a privilege escalation is to overwrite a kernel function pointer, and trigger that function. Based on the exploit for CVE-2010-3081, I opted to overwrite the security_ops function pointer table. Their use of msg_queue_msgctl wasn t very good for the general case since it s near the end of the table and its offset would depend on kernel versions. Initially I opted for getcap, but in the end used ptrace_traceme, both of which are very near the top the security_ops structure. (Though I need share credit here with Dan Rosenberg as we were working together on improving the reliability of the security_ops overwrite method. He used the same approach for his excellent RDS exploit.) Here are the steps for one way of taking an arbitrary kernel memory write and turning it into a root escalation:

• overwrite security_ops with default_security_ops, which will revert the LSM back to the capabilities-only security operations. This, however, means we can calculate where cap_ptrace_traceme is.
• overwrite default_security_ops->ptrace_traceme to point to our supplied function that will actually perform the privilege escalation (thanks to Brad Spengler for his code from Enlightenment).
• trigger the function (in this case, call ptrace(PTRACE_TRACEME, 0, NULL, NULL)).
• restore default_security_ops->ptrace_traceme to point to cap_ptrace_traceme so the next caller doesn t Oops the system (since userspace memory will be remapped).

Here s the source for Vyakarana as seen running in Enlightenment using cap_getcap (which is pretty unstable, so you might want to switch it to use ptrace_traceme), and as a stand-alone memory writer. Conclusions: Keep auditing the kernel for more arbitrary writes; I think there are still many left. Reduce the exploitation surface within the kernel itself (which PaX and grsecurity have been doing for a while now), specifically:

• Block userspace memory access while in kernel mode. This would stop the ability to make the kernel start executing functions that live in userspace a clear privilege violation. This protection would stop the current exploit above, but the exploit could be adjusted to use kernel memory instead.
• Keep function pointers read-only. There is no reason for these function pointer tables (fops, IDT, security_ops, etc) to be writable. These should all be marked correctly, with inline code exceptions being made for updating the global pointers to those tables, leaving the pointer read-only after it gets set. This would stop this particular exploit above, but there are still plenty more targets.
• Randomize the kernel stack location on a per-syscall basis. This will stop exploits that depend on a stable kernel stack location (as this exploit does).

The PSAS team planned to have their LV2.3 airframe updates ready for BALLS this year, but RL interfered and they weren t ready to go on time. A quick bit of rescheduling and we decided to fly over the weekend of the 16-17 of October. Tsolo and family welcomed us warmly as we arrived on Saturday afternoon after driving over from Portland. They ve got a new puppy who is also cute and friendly. We managed to get the launch tower and flight operations set up before dark, cooked dinner and spent the evening prepping the airframe. It was cold overnight, but the light cloud cover that had been there when we arrived was nearly gone by morning. I called in to open the waiver and was asked to hold until noon, which suited us just fine. The rocket finally made it onto the rail around 1:30 and we managed to convince the launch controller to actually light the motor at 2:44:39 (according to the GPS data). Flying on a CTI N2850 blue-streak, LV2.3 hit about 380m/s and reached 4851m. This was the first flight with the new fin system, you can see how that works in the video here: <iframe frameborder="0" height="480" src="http://player.vimeo.com/video/15972443" width="640"></iframe>Portland State Aerospace LV2.3 flight with roll control from Keith Packard on Vimeo. The roll control system worked as designed, executing a programmed sequence of maneuvers during ascent. You can see the canard fins moving back and forth in the video, controlling the roll of the airframe. Yes, the fins really do spin separately from the airframe. You can see how that was constructed here: PSAS LV2.3 Spin Can Live telemetry and stored flight data, consisting of GPS coordinates along with barometry altimeter and accelerometer information, was collected using the TeleMetrum flight computer. The airframe was recovered about 800m downrange. Thanks to Portland State University for their support in hosting PSAS and Oregon Rocketry for letting us fly at their launch site.

Award winning code Me and Yuwei had a fun day at hhhmcr (#hhhmcr) and even managed to put together a prototype that won the first prize \o/ We played with the gmp24 dataset kindly extracted from Twitter by Michael Brunton-Spall of the Guardian into a convenient JSON dataset. The idea was to find ways of making it easier to look at the data and making sense of it. This is the story of what we did, including the code we wrote. The original dataset has several JSON files, so the first task was to put them all together:

#!/usr/bin/python
# Merge the JSON data
# (C) 2010 Enrico Zini <enrico@enricozini.org>
# License: WTFPL version 2 (http://sam.zoy.org/wtfpl/)
import simplejson
import os
res = []
for f in os.listdir("."):
    if not f.startswith("gmp24"): continue
    data = open(f).read().strip()
    if data == "[]": continue
    parsed = simplejson.loads(data)
    res.extend(parsed)
print simplejson.dumps(res)

The results however were not ordered by date, as GMP had to use several accounts to twit because Twitter was putting Greather Manchester Police into jail for generating too much traffic. There would be quite a bit to write about that, but let's stick to our work. Here is code to sort the JSON data by time:

#!/usr/bin/python
# Sort the JSON data
# (C) 2010 Enrico Zini <enrico@enricozini.org>
# License: WTFPL version 2 (http://sam.zoy.org/wtfpl/)
import simplejson
import sys
import datetime as dt
all_recs = simplejson.load(sys.stdin)
all_recs.sort(key=lambda x: dt.datetime.strptime(x["created_at"], "%a %b %d %H:%M:%S +0000 %Y"))
simplejson.dump(all_recs, sys.stdout)

I then wanted to play with Tf-idf for extracting the most important words of every tweet:

#!/usr/bin/python
# tfifd - Annotate JSON elements with Tf-idf extracted keywords
#
# Copyright (C) 2010  Enrico Zini <enrico@enricozini.org>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
import sys, math
import simplejson
import re
# Read all the twits
records = simplejson.load(sys.stdin)
# All the twits by ID
byid = dict(((x["id"], x) for x in records))
# Stopwords we ignore
stopwords = set(["by", "it", "and", "of", "in", "a", "to"])
# Tokenising engine
re_num = re.compile(r"^\d+$")
re_word = re.compile(r"(\w+)")
def tokenise(tweet):
    "Extract tokens from a tweet"
    for tok in tweet["text"].split():
        tok = tok.strip().lower()
        if re_num.match(tok): continue
        mo = re_word.match(tok)
        if not mo: continue
        if mo.group(1) in stopwords: continue
        yield mo.group(1)
# Extract tokens from tweets
tokenised = dict(((x["id"], list(tokenise(x))) for x in records))
# Aggregate token counts
aggregated =  
for d in byid.iterkeys():
    for t in tokenised[d]:
        if t in aggregated:
            aggregated[t] += 1
        else:
            aggregated[t] = 1
def tfidf(doc, tok):
    "Compute TFIDF score of a token in a document"
    return doc.count(tok) * math.log(float(len(byid)) / aggregated[tok])
# Annotate tweets with keywords
res = []
for name, tweet in byid.iteritems():
    doc = tokenised[name]
    keywords = sorted(set(doc), key=lambda tok: tfidf(doc, tok), reverse=True)[:5]
    tweet["keywords"] = keywords
    res.append(tweet)
simplejson.dump(res, sys.stdout)

I thought this was producing a nice summary of every tweet but nobody was particularly interested, so we moved on to adding categories to tweet. Thanks to Yuwei who put together some useful keyword sets, we managed to annotate each tweet with a place name (i.e. "Stockport"), a social place name (i.e. "pub", "bank") and a social category (i.e. "man", "woman", "landlord"...) The code is simple; the biggest work in it was the dictionary of keywords:

#!/usr/bin/python
# categorise - Annotate JSON elements with categories
#
# Copyright (C) 2010  Enrico Zini <enrico@enricozini.org>
# Copyright (C) 2010  Yuwei Lin <yuwei@ylin.org>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
import sys, math
import simplejson
import re
# Electoral wards from http://en.wikipedia.org/wiki/List_of_electoral_wards_in_Greater_Manchester
placenames = ["Altrincham", "Sale West",
"Altrincham", "Ashton upon Mersey", "Bowdon", "Broadheath", "Hale Barns", "Hale Central", "St Mary", "Timperley", "Village",
"Ashton-under-Lyne",
"Ashton Hurst", "Ashton St Michael", "Ashton Waterloo", "Droylsden East", "Droylsden West", "Failsworth East", "Failsworth West", "St Peter",
"Blackley", "Broughton",
"Broughton", "Charlestown", "Cheetham", "Crumpsall", "Harpurhey", "Higher Blackley", "Kersal",
"Bolton North East",
"Astley Bridge", "Bradshaw", "Breightmet", "Bromley Cross", "Crompton", "Halliwell", "Tonge with the Haulgh",
"Bolton South East",
"Farnworth", "Great Lever", "Harper Green", "Hulton", "Kearsley", "Little Lever", "Darcy Lever", "Rumworth",
"Bolton West",
"Atherton", "Heaton", "Lostock", "Horwich", "Blackrod", "Horwich North East", "Smithills", "Westhoughton North", "Chew Moor", "Westhoughton South",
"Bury North",
"Church", "East", "Elton", "Moorside", "North Manor", "Ramsbottom", "Redvales", "Tottington",
"Bury South",
"Besses", "Holyrood", "Pilkington Park", "Radcliffe East", "Radcliffe North", "Radcliffe West", "St Mary", "Sedgley", "Unsworth",
"Cheadle",
"Bramhall North", "Bramhall South", "Cheadle", "Gatley", "Cheadle Hulme North", "Cheadle Hulme South", "Heald Green", "Stepping Hill",
"Denton", "Reddish",
"Audenshaw", "Denton North East", "Denton South", "Denton West", "Dukinfield", "Reddish North", "Reddish South",
"Hazel Grove",
"Bredbury", "Woodley", "Bredbury Green", "Romiley", "Hazel Grove", "Marple North", "Marple South", "Offerton",
"Heywood", "Middleton",
"Bamford", "Castleton", "East Middleton", "Hopwood Hall", "Norden", "North Heywood", "North Middleton", "South Middleton", "West Heywood", "West Middleton",
"Leigh",
"Astley Mosley Common", "Atherleigh", "Golborne", "Lowton West", "Leigh East", "Leigh South", "Leigh West", "Lowton East", "Tyldesley",
"Makerfield",
"Abram", "Ashton", "Bryn", "Hindley", "Hindley Green", "Orrell", "Winstanley", "Worsley Mesnes",
"Manchester Central",
"Ancoats", "Clayton", "Ardwick", "Bradford", "City Centre", "Hulme", "Miles Platting", "Newton Heath", "Moss Side", "Moston",
"Manchester", "Gorton",
"Fallowfield", "Gorton North", "Gorton South", "Levenshulme", "Longsight", "Rusholme", "Whalley Range",
"Manchester", "Withington",
"Burnage", "Chorlton", "Chorlton Park", "Didsbury East", "Didsbury West", "Old Moat", "Withington",
"Oldham East", "Saddleworth",
"Alexandra", "Crompton", "Saddleworth North", "Saddleworth South", "Saddleworth West", "Lees", "St James", "St Mary", "Shaw", "Waterhead",
"Oldham West", "Royton",
"Chadderton Central", "Chadderton North", "Chadderton South", "Coldhurst", "Hollinwood", "Medlock Vale", "Royton North", "Royton South", "Werneth",
"Rochdale",
"Balderstone", "Kirkholt", "Central Rochdale", "Healey", "Kingsway", "Littleborough Lakeside", "Milkstone", "Deeplish", "Milnrow", "Newhey", "Smallbridge", "Firgrove", "Spotland", "Falinge", "Wardle", "West Littleborough",
"Salford", "Eccles",
"Claremont", "Eccles", "Irwell Riverside", "Langworthy", "Ordsall", "Pendlebury", "Swinton North", "Swinton South", "Weaste", "Seedley",
"Stalybridge", "Hyde",
"Dukinfield Stalybridge", "Hyde Godley", "Hyde Newton", "Hyde Werneth", "Longdendale", "Mossley", "Stalybridge North", "Stalybridge South",
"Stockport",
"Brinnington", "Central", "Davenport", "Cale Green", "Edgeley", "Cheadle Heath", "Heatons North", "Heatons South", "Manor",
"Stretford", "Urmston",
"Bucklow-St Martins", "Clifford", "Davyhulme East", "Davyhulme West", "Flixton", "Gorse Hill", "Longford", "Stretford", "Urmston",
"Wigan",
"Aspull New Springs Whelley", "Douglas", "Ince", "Pemberton", "Shevington with Lower Ground", "Standish with Langtree", "Wigan Central", "Wigan West",
"Worsley", "Eccles South",
"Barton", "Boothstown", "Ellenbrook", "Cadishead", "Irlam", "Little Hulton", "Walkden North", "Walkden South", "Winton", "Worsley",
"Wythenshawe", "Sale East",
"Baguley", "Brooklands", "Northenden", "Priory", "Sale Moor", "Sharston", "Woodhouse Park"]
# Manual coding from Yuwei
placenames.extend(["City centre", "Tameside", "Oldham", "Bury", "Bolton",
"Trafford", "Pendleton", "New Moston", "Denton", "Eccles", "Leigh", "Benchill",
"Prestwich", "Sale", "Kearsley", ])
placenames.extend(["Trafford", "Bolton", "Stockport", "Levenshulme", "Gorton",
"Tameside", "Blackley", "City centre", "Airport", "South Manchester",
"Rochdale", "Chorlton", "Uppermill", "Castleton", "Stalybridge", "Ashton",
"Chadderton", "Bury", "Ancoats", "Whalley Range", "West Yorkshire",
"Fallowfield", "New Moston", "Denton", "Stretford", "Eccles", "Pendleton",
"Leigh", "Altrincham", "Sale", "Prestwich", "Kearsley", "Hulme", "Withington",
"Moss Side", "Milnrow", "outskirt of Manchester City Centre", "Newton Heath",
"Wythenshawe", "Mancunian Way", "M60", "A6", "Droylesden", "M56", "Timperley",
"Higher Ince", "Clayton", "Higher Blackley", "Lowton", "Droylsden",
"Partington", "Cheetham Hill", "Benchill", "Longsight", "Didsbury",
"Westhoughton"])
# Social categories from Yuwei
soccat = ["man", "woman", "men", "women", "youth", "teenager", "elderly",
"patient", "taxi driver", "neighbour", "male", "tenant", "landlord", "child",
"children", "immigrant", "female", "workmen", "boy", "girl", "foster parents",
"next of kin"]
for i in range(100):
    soccat.append("%d-year-old" % i)
    soccat.append("%d-years-old" % i)
# Types of social locations from Yuwei
socloc = ["car park", "park", "pub", "club", "shop", "premises", "bus stop",
"property", "credit card", "supermarket", "garden", "phone box", "theatre",
"toilet", "building site", "Crown court", "hard shoulder", "telephone kiosk",
"hotel", "restaurant", "cafe", "petrol station", "bank", "school",
"university"]
extras =   "placename": placenames, "soccat": soccat, "socloc": socloc  
# Normalise keyword lists
for k, v in extras.iteritems():
    # Remove duplicates
    v = list(set(v))
    # Sort by length
    v.sort(key=lambda x:len(x), reverse=True)
# Add keywords
def add_categories(tweet):
    text = tweet["text"].lower()
    for field, categories in extras.iteritems():
        for cat in categories:
            if cat.lower() in text:
                tweet[field] = cat
                break
    return tweet
# Read all the twits
records = (add_categories(x) for x in simplejson.load(sys.stdin))
simplejson.dump(list(records), sys.stdout)

All these scripts form a nice processing chain: each script takes a list of JSON records, adds some bit and passes it on. In order to see what we have so far, here is a simple script to convert the JSON twits to CSV so they can be viewed in a spreadsheet:

#!/usr/bin/python
# Convert the JSON twits to CSV
# (C) 2010 Enrico Zini <enrico@enricozini.org>
# License: WTFPL version 2 (http://sam.zoy.org/wtfpl/)
import simplejson
import sys
import csv
rows = ["id", "created_at", "text", "keywords", "placename"]
writer = csv.writer(sys.stdout)
for rec in simplejson.load(sys.stdin):
    rec["keywords"] = " ".join(rec["keywords"])
    rec["placename"] = rec.get("placename", "")
    writer.writerow([rec[row] for row in rows])

At this point we were coming up with lots of questions: "were there more reports on women or men?", "which place had most incidents?", "what were the incidents involving animals?"... Time to bring Xapian into play. This script reads all the JSON tweets and builds a Xapian index with them:

#!/usr/bin/python
# toxapian - Index JSON tweets in Xapian
#
# Copyright (C) 2010  Enrico Zini <enrico@enricozini.org>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
import simplejson
import sys
import os, os.path
import xapian
DBNAME = sys.argv[1]
db = xapian.WritableDatabase(DBNAME, xapian.DB_CREATE_OR_OPEN)
stemmer = xapian.Stem("english")
indexer = xapian.TermGenerator()
indexer.set_stemmer(stemmer)
indexer.set_database(db)
data = simplejson.load(sys.stdin)
for rec in data:
    doc = xapian.Document()
    doc.set_data(str(rec["id"]))
    indexer.set_document(doc)
    indexer.index_text_without_positions(rec["text"])
    # Index categories as categories
    if "placename" in rec:
        doc.add_boolean_term("XP" + rec["placename"].lower())
    if "soccat" in rec:
        doc.add_boolean_term("XS" + rec["soccat"].lower())
    if "socloc" in rec:
        doc.add_boolean_term("XL" + rec["socloc"].lower())
    db.add_document(doc)
db.flush()
# Also save the whole dataset so we know where to find it later if we want to
# show the details of an entry
simplejson.dump(data, open(os.path.join(DBNAME, "all.json"), "w"))

And this is a simple command line tool to query to the database:

#!/usr/bin/python
# xgrep - Command line tool to query the GMP24 tweet Xapian database
#
# Copyright (C) 2010  Enrico Zini <enrico@enricozini.org>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
import simplejson
import sys
import os, os.path
import xapian
DBNAME = sys.argv[1]
db = xapian.Database(DBNAME)
stem = xapian.Stem("english")
qp = xapian.QueryParser()
qp.set_default_op(xapian.Query.OP_AND)
qp.set_database(db)
qp.set_stemmer(stem)
qp.set_stemming_strategy(xapian.QueryParser.STEM_SOME)
qp.add_boolean_prefix("place", "XP")
qp.add_boolean_prefix("soc", "XS")
qp.add_boolean_prefix("loc", "XL")
query = qp.parse_query(sys.argv[2],
    xapian.QueryParser.FLAG_BOOLEAN  
    xapian.QueryParser.FLAG_LOVEHATE  
    xapian.QueryParser.FLAG_BOOLEAN_ANY_CASE  
    xapian.QueryParser.FLAG_WILDCARD  
    xapian.QueryParser.FLAG_PURE_NOT  
    xapian.QueryParser.FLAG_SPELLING_CORRECTION  
    xapian.QueryParser.FLAG_AUTO_SYNONYMS)
enquire = xapian.Enquire(db)
enquire.set_query(query)
count = 40
matches = enquire.get_mset(0, count)
estimated = matches.get_matches_estimated()
print "%d/%d results" % (matches.size(), estimated)
data = dict((str(x["id"]), x) for x in simplejson.load(open(os.path.join(DBNAME, "all.json"))))
for m in matches:
    rec = data[m.document.get_data()]
    print rec["text"]
print "%d/%d results" % (matches.size(), matches.get_matches_estimated())
total = db.get_doccount()
estimated = matches.get_matches_estimated()
print "%d results over %d documents, %d%%" % (estimated, total, estimated * 100 / total)

Neat! Now that we have a proper index that supports all sort of cool things, like stemming, tag clouds, full text search with complex queries, lookup of similar documents, suggest keywords and so on, it was just fair to put together a web service to share it with other people at the event. It helped that I had already written similar code for apt-xapian-index and dde before. Here is the server, quickly built on bottle. The very last line starts the server and it is where you can configure the listening interface and port.

#!/usr/bin/python
# xserve - Make the GMP24 tweet Xapian database available on the web
#
# Copyright (C) 2010  Enrico Zini <enrico@enricozini.org>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
import bottle
from bottle import route, post
from cStringIO import StringIO
import cPickle as pickle
import simplejson
import sys
import os, os.path
import xapian
import urllib
import math
bottle.debug(True)
DBNAME = sys.argv[1]
QUERYLOG = os.path.join(DBNAME, "queries.txt")
data = dict((str(x["id"]), x) for x in simplejson.load(open(os.path.join(DBNAME, "all.json"))))
prefixes =   "place": "XP", "soc": "XS", "loc": "XL"  
prefix_desc =   "place": "Place name", "soc": "Social category", "loc": "Social location"  
db = xapian.Database(DBNAME)
stem = xapian.Stem("english")
qp = xapian.QueryParser()
qp.set_default_op(xapian.Query.OP_AND)
qp.set_database(db)
qp.set_stemmer(stem)
qp.set_stemming_strategy(xapian.QueryParser.STEM_SOME)
for k, v in prefixes.iteritems():
    qp.add_boolean_prefix(k, v)
def make_query(qstring):
    return qp.parse_query(qstring,
        xapian.QueryParser.FLAG_BOOLEAN  
        xapian.QueryParser.FLAG_LOVEHATE  
        xapian.QueryParser.FLAG_BOOLEAN_ANY_CASE  
        xapian.QueryParser.FLAG_WILDCARD  
        xapian.QueryParser.FLAG_PURE_NOT  
        xapian.QueryParser.FLAG_SPELLING_CORRECTION  
        xapian.QueryParser.FLAG_AUTO_SYNONYMS)
@route("/")
def index():
    query = urllib.unquote_plus(bottle.request.GET.get("q", ""))
    out = StringIO()
    print >>out, '''
<html>
<head>
<title>Query</title>
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js"></script>
<script type="text/javascript">
$(function() 
    $("#queryfield")[0].focus()
 )
</script>
</head>
<body>
<h1>Search</h1>
<form method="POST" action="/query">
Keywords: <input type="text" name="query" value="%s" id="queryfield">
<input type="submit">
<a href="http://xapian.org/docs/queryparser.html">Help</a>
</form>''' % query
    print >>out, '''
<p>Example: "car place:wigan"</p>

<p>Available prefixes:</p>

<ul>
'''
    for pfx in prefixes.keys():
        print >>out, "<li><a href='/catinfo/%s'>%s - %s</a></li>" % (pfx, pfx, prefix_desc[pfx])
    print >>out, '''
</ul>
'''
    oldqueries = []
    if os.path.exists(QUERYLOG):
        total = db.get_doccount()
        fd = open(QUERYLOG, "r")
        while True:
            try:
                q = pickle.load(fd)
            except EOFError:
                break
            oldqueries.append(q)
        fd.close()
        def print_query(q):
            count = q["count"]
            print >>out, "<li><a href='/query?query=%s'>%s (%d/%d %.2f%%)</a></li>" % (urllib.quote_plus(q["q"]), q["q"], count, total, count * 100.0 / total)
        print >>out, "<p>Last 10 queries:</p><ul>"
        for q in oldqueries[:-10:-1]:
            print_query(q)
        print >>out, "</ul>"
        # Remove duplicates
        oldqueries = dict(((x["q"], x) for x in oldqueries)).values()
        print >>out, "<table>"
        print >>out, "<tr><th>10 queries with most results</th><th>10 queries with least results</th></tr>"
        print >>out, "<tr><td>"
        print >>out, "<ul>"
        oldqueries.sort(key=lambda x:x["count"], reverse=True)
        for q in oldqueries[:10]:
            print_query(q)
        print >>out, "</ul>"
        print >>out, "</td><td>"
        print >>out, "<ul>"
        nonempty = [x for x in oldqueries if x["count"] > 0]
        nonempty.sort(key=lambda x:x["count"])
        for q in nonempty[:10]:
            print_query(q)
        print >>out, "</ul>"
        print >>out, "</td></tr>"
        print >>out, "</table>"
    print >>out, '''
</body>
</html>'''
    return out.getvalue()
@route("/query")
@route("/query/")
@post("/query")
@post("/query/")
def query():
    query = bottle.request.POST.get("query", bottle.request.GET.get("query", ""))
    enquire = xapian.Enquire(db)
    enquire.set_query(make_query(query))
    count = 40
    matches = enquire.get_mset(0, count)
    estimated = matches.get_matches_estimated()
    total = db.get_doccount()
    out = StringIO()
    print >>out, '''
<html>
<head><title>Results</title></head>
<body>
<h1>Results for "<b>%s</b>"</h1>
''' % query
    if estimated == 0:
        print >>out, "No results found."
    else:
        # Give as results the first 30 documents; also use them as the key
        # ones to use to compute relevant terms
        rset = xapian.RSet()
        for m in enquire.get_mset(0, 30):
            rset.add_document(m.document.get_docid())
        # Compute the tag cloud
        class NonTagFilter(xapian.ExpandDecider):
            def __call__(self, term):
                return not term[0].isupper() and not term[0].isdigit()
        cloud = []
        maxscore = None
        for res in enquire.get_eset(40, rset, NonTagFilter()):
            # Normalise the score in the interval [0, 1]
            weight = math.log(res.weight)
            if maxscore == None: maxscore = weight
            tag = res.term
            cloud.append([tag, float(weight) / maxscore])
        max_weight = cloud[0][1]
        min_weight = cloud[-1][1]
        cloud.sort(key=lambda x:x[0])
        def mklink(query, term):
            return "/query?query=%s" % urllib.quote_plus(query + " and " + term)
        print >>out, "<h2>Tag cloud</h2>"
        print >>out, "<blockquote>"
        for term, weight in cloud:
            size = 100 + 100.0 * (weight - min_weight) / (max_weight - min_weight)
            print >>out, "<a href='%s' style='font-size:%d%%; color:brown;'>%s</a>" % (mklink(query, term), size, term)
        print >>out, "</blockquote>"
        print >>out, "<h2>Results</h2>"
        print >>out, "<p><a href='/'>Search again</a></p>"
        print >>out, "<p>%d results over %d documents, %.2f%%</p>" % (estimated, total, estimated * 100.0 / total)
        print >>out, "<p>%d/%d results</p>" % (matches.size(), estimated)
        print >>out, "<ul>"
        for m in matches:
            rec = data[m.document.get_data()]
            print >>out, "<li><a href='/item/%s'>%s</a></li>" % (rec["id"], rec["text"])
        print >>out, "</ul>"
        fd = open(QUERYLOG, "a")
        qinfo = dict(q=query, count=estimated)
        pickle.dump(qinfo, fd)
        fd.close()
    print >>out, '''
<a href="/">Search again</a>

</body>
</html>'''
    return out.getvalue()
@route("/item/:id")
@route("/item/:id/")
def show(id):
    rec = data[id]
    out = StringIO()
    print >>out, '''
<html>
<head><title>Result %s</title></head>
<body>
<h1>Raw JSON record for twit %s</h1>
<pre>''' % (rec["id"], rec["id"])
    print >>out, simplejson.dumps(rec, indent=" ")
    print >>out, '''
</pre>
</body>
</html>'''
    return out.getvalue()
@route("/catinfo/:name")
@route("/catinfo/:name/")
def catinfo(name):
    prefix = prefixes[name]
    out = StringIO()
    print >>out, '''
<html>
<head><title>Values for %s</title></head>
<body>
''' % name
    terms = [(x.term[len(prefix):], db.get_termfreq(x.term)) for x in db.allterms(prefix)]
    terms.sort(key=lambda x:x[1], reverse=True)
    freq_min = terms[0][1]
    freq_max = terms[-1][1]
    def mklink(name, term):
        return "/query?query=%s" % urllib.quote_plus(name + ":" + term)
    # Build tag cloud
    print >>out, "<h1>Tag cloud</h1>"
    print >>out, "<blockquote>"
    for term, freq in sorted(terms[:20], key=lambda x:x[0]):
        size = 100 + 100.0 * (freq - freq_min) / (freq_max - freq_min)
        print >>out, "<a href='%s' style='font-size:%d%%; color:brown;'>%s</a>" % (mklink(name, term), size, term)
    print >>out, "</blockquote>"
    print >>out, "<h1>All terms</h1>"
    print >>out, "<table>"
    print >>out, "<tr><th>Occurrences</th><th>Name</th></tr>"
    for term, freq in terms:
        print >>out, "<tr><td>%d</td><td><a href='/query?query=%s'>%s</a></td></tr>" % (freq, urllib.quote_plus(name + ":" + term), term)
    print >>out, "</table>"
    print >>out, '''
</body>
</html>'''
    return out.getvalue()
# Change here for bind host and port
bottle.run(host="0.0.0.0", port=8024)

...and then we presented our work and ended up winning the contest. This was the story of how we wrote this set of award winning code.

Here are the Debian users who have submitted a request to appear in our website so far in this year. Please welcome them into our Project!

1dental.com: Commercial company from US.

A.S.D. Irishmassa American Football Team: Non-profit organization from Italy

Centro de Comunicaci n Cient fica, Universidad de Buenos Aires: University from Argentina.

Creppolo, crepes e piadine: Commercial company from Italy.

Eye Of The Beholder BBS: Non-profit organization from Spain.

IT Services, Medhurst Communications Ltd.: Commercial company from UK.

JSC VS: Commercial company from Russia.

King Abdulaziz City for Science and Technology (KACST): Academic section from Saudi Arabia

Lumut MARA Vocational Institute: Educational institution from Malaysia.

Madkom Ltd.: Commercial company from Poland.

Media-X Systems Inc.: Commercial company from Canada.

Microbiology laboratory. Science Faculty. UNAM: University from Mexico.

Nimbus Hookah Lounge: Commercial company from US.

Nomura Technical Management Office Ltd.: Commercial company from Japan.

oriented.net Web Hosting: Commercial company from Switzerland.

Parkyeri: Software development company from Turkey.

Pastoral da Crian a: Non-profit organization from Brazil.

XSoft Ltd.: Software development company from Bulgaria.

Ziehm Computer Repair: Commercial company from US.

And here are some of their reasons to choose Debian:

We have chosen Debian over other alternatives; because of its reliability and easiness of maintenance.

The decision was based on the selection of additional expandable components, availability of distribution, a regular cycle for issuing amendments, stability and support solutions for a wide range of equipment for a dedicated server solutions.

Stability is important for us.

The main reason for choosing Debian over other distributions is the package management, security, number of available packages, ease-of-use, stability, amount of quality documentation, and cost.

We choose Debian to easen the burden of system administration. Also because Debian has very well maintaned packages and for high security.

Debian is powerful and keeping originality of Linux.

We find the software that comes with Debian very useful and easy to use since we are not specialists in computer matters.

Debian is the most powerful Linux distribution! The best choice for our jobs, our servers and our lifestyle.

We chose Debian because it is stable, simple and fast to install and to use, and because it is Free Software.

We are proud to say that we use Debian/GNU Linux on more than 90% of our servers and this simply because of it s stability, security and great packaging system.

Debian offered the perfect balance between security, stability and ease of administration.

We chose Debian for its rock-solid stability, ease of installation and configuration, and awesome ability to not only run on old, second-hand hardware, but to turn that hardware into powerful production machines perfect for our needs. We also like Debian s Social Contract. None of the other options were as successful in this implementation.

It is refreshing and enjoyable to have an operating system which gives users easy access.

Thanks very much for the hard work, Webmaster Team.

After the famous Facebook outage a few days ago, Facebook Engineering made a to be fair, reasonably detailed statement on what went wrong and how it affected the service. One particular comment attached to it drew my attention:

It s great to hear and see that big companies like Facebook are so open with what they do. That s rare, very rare. Thanks!

Huh? Did I miss some announcement of openness and freedom?
<script type="text/javascript"> var flattr_wp_ver = '0.9.16'; var flattr_uid = '32970'; var flattr_url = 'http://www.jwiltshire.org.uk/content'; var flattr_lng = 'en_GB'; var flattr_cat = 'text'; var flattr_tag = 'blog,wordpress,rss,feed'; var flattr_btn = 'large'; var flattr_tle = 'jwiltshire.org.uk'; var flattr_dsc = 'The public face of jwiltshire'; </script> <script src="https://api.flattr.com/js/0.5.0/load.js?mode=auto" type="text/javascript"></script>

As I'm currently attending the EUgridPMA meeting in Zagreb I thought I'd share a bit of this project I've been working on for the past year: the TCS eScience project. In the scientific world lots of calculations are performed on distributed computing platforms known as grid. Because users of other institutions will be using your hardware, authentication is needed and this problem has been solved with x.509 personal certificates. The problem however, is that these certificates of course have to be issued by some CA. Currently in Europe alone there are over 40 active CA's, even multiple per country, dedicated to this job. They are accredited through the EUgridPMA which meets regularly. For scientists, it's often cumbersome to obtain a certificate: find your local CA, present an ID (probably in person), and sometime later receive your certificate. The process can take days or even weeks. Scientists are not interested in CA's but just want to practice science. Our solution is a central web portal where users can request a certificate and have it delivered in minutes. This leverages the fact that identities of scientists normally have already been vetted at their home institution: users log in to the portal via federated login. Their home institution passes a special attribute that declares "Yes, we have really seen photo ID of this person and the name is correct". This attribute must of course not be passed for guests or test users or role accounts. However, it may still be easy to mass-provision it. In the Netherlands for example, the employer is required by law to verify the identity of each employee, so all employees can be automatically assigned the attribute. After logging in and uploading (or generating) a csr, the request is passed in the back end to the Comodo API. This also means that we do not need to perform the complex operations of running an online CA (with hardware crypto devices, crl's, etc.). The use of Comodo is part of the same deal as the TERENA Certificate Service for host SSL certificates. The Comodo API responds within two minutes with the certificate which the user can download. Currently 10 European countries are involved with the project (nl no se fi dk at cz it fr be), and more have shown interest. The certificates we issue have been accredited by the EUgridPMA so can be used on the grid. A separate but similar service is being set up for 'regular' personal certificates for the academic community, e.g. for s/mime usage. More details are in the presentation and paper by portal software developers Henrik and Thomas at the most recent TNC.