Category Archives: Open Source

Open Source, Free Software, and similar

The Rockbox app part II

Hey

In February I wrote about how I think Rockbox’s future involves existing as an app (on Android), and it was also this year accepted as a gsoc project for Rockbox.

In June I got somewhat noticed when Joe Brockmeier wrote about Rockbox on lwn.net and included a lot of references and talk about my post and the app situtation.

Today, Thomas “kugel” Martitz closed the circle by announcing on IRC and mail that he has indeed made Rockbox on Android play its first sounds and he is indeed progressing in a good direction.

While I’m told the current state is rough and there’s no installer or anything yet, I’m sure I share the view of lots of others that this is a great moment in the Rockbox history. A milestone. Thanks Thomas, I hope your work continues equally good and that we get an app to try out at the end of the summer or so.

Thomas’ git repo is here: http://repo.or.cz/w/kugel-rb.git

Rockbox

I’ll talk at FSCONS 2010

Recently I was informed that I got two talks accepted to the FSCONS 2010 conference, to be held in the beginning of November 2010.

My talks will be about the Future and current state of internet transport protocols (TCP, HTTP, SPDY, WebSockets, SCTP and more) and on High performance multi-protocol applications with libcurl, which will educate the audience on how to use libcurl when doing high performance clients with potentially a very large number of simultaneous transfers. A somewhat clueful reader will of course spot that these two talks have a lot in common, and yeah they do reveal a lot of what I do and what I like and what I poke on these days. I hope I’ll be able to put the light on some things not everyone is already perfectly aware of.

The talks will be held in English, and if the past FSCONS conferences tell anything, my talks will be video filmed and become available online afterward for the world to see if you have a funeral or something to attend to that prevents you from actually attending in person.

If you have thoughts, questions or anything on these topics that you would like to get answered in my talk, feel free to bring them up and I’ll see what I can do.

(If those fine guys and gals at FSCONS ever settled for a logo, or had one I could link to, I would’ve shown one of them right here.)

C-ares, now and ahead!

The project c-ares started many years ago (March 2004) when I decided to fork the existing ares project to get the changes done that I deemed necessary – and the original project owner didn’t want them.

I did my original work on c-ares back then primarily to get a good asynchronous name resolver for libcurl so that we would get around the limitation of having to do the name resolves totally synchronously as the libc interfaces mandate. Of course, c-ares was and is more than just name resolving and not too surprisingly, there have popped up other projects that are now using c-ares.

I’m maintaining a bunch of open source projects, and c-ares was never one that I felt a lot of love for, it was mostly a project that I needed to get done and when things worked the way I wanted them I found myself having ended up as maintainer for yet another project. I’ve repeatedly mentioned on the c-ares mailing list that I don’t really have time to maintain it and that I’d rather step down and let someone else “take over”.

After having said this for over 4 years, I’ve come to accept that even though c-ares has many users out there, and even seems to be appreciated by companies and open source projects, there just isn’t any particular big desire to help out in our project. I find it very hard to just “give up” a functional project, so I linger and do my best to give it the efforts and love it needs. I very much need and want help to maintain and develop c-ares. I’m not doing a very good job with it right now.

Threaded name resolves competes

I once thought we would be able to make c-ares capable of becoming a true drop-in replacement for the native system name resolver functions, but over the years with c-ares I’ve learned that the dusty corners of name resolving in unix and Linux have so many features and fancy stuff that c-ares is still a long way from that. It has also made me turn around somewhat and I’ve reconsidered that perhaps using a threaded native resolver is the better way for libcurl to do asynchronous name resolves. That way we don’t need any half-baked implementations of the resolver. Of course it comes at the price of a new thread for each name resolve, which turns really nasty of you grow the number of connections just a tad bit, but still most libcurl-using applications today hardly use more than just a few (say less than a hundred) simultaneous transfers.

Future!

I don’t think the future has any radical changes or drastically new stuff in the pipe for c-ares. I think we should keep polishing off bugs and add the small functions and features that we’re missing. I believe we’re not yet parsing all records we could do, to a convenient format.

As usual, a project is not about how much we can add but about how much we can avoid adding and how much we can remain true to our core objectives. I wish the growing popularity will make more people join the project and then not only to through a single patch at us, but to also hand around a while and help us somewhat more.

Hopefully we will one day be able to use c-ares instead of a typical libc-based name resolver and yet resolve the same names.

Join us and help us give c-ares a better future!

c-ares

Java apps froze my Iceweasel

I’ve noticed for quite some time that java apps haven’t seemed to work on my computer when I try to use them with my browser. Whenever I’ve started most java apps, my entire browser has just frozen and gone completely unresponsive and I’ve been forced to kill and restart it.

I run Debian Linux on just about all my machines so of course I do that on my primary desktop as well. And Iceweasel is my browser.

I’ve not really bothered much about the problem as java applets are a bit of yesterday’s technology and I rarely face anything in java that I need. Until today, when I had to login to a customer’s site and use an applet for some work related to my job. There was no decent way to avoid it (apart from perhaps logging in using another machine/browser or similar), so I decided to bite the bullet and finally fix my issue.

I searched around and I tried uninstalling all openjdk stuff and more. I restarted Iceweasel countless times to no avail.

Finally I stumbled over this post by user “almatic” and voila, it fixed my problem. As I just wasted like an hour on this, I’ll help out to make the world a little better by providing the answer here as well:

open file /etc/sysctl.d/bindv6only.conf and set net.ipv6.bindv6only=0, then restart the procfs with invoke-rc.d procps restart

here are the corresponding bugs

http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=560238
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=560056

Community Hack

OWASP Sweden and FOSS-STHLM are doing a joint effort and we’re putting together Community Hack #2 on September 4-5 2010 here in Stockholm, Sweden.

We are looking for sponsors and facilities to use for this event, please get in touch!

The goal here is to gather a group of interested people. Everyone brings their own ideas of what to accomplish, communicate the intentions to the group and then work together during the weekend to try to reach the set goals. Suitable things, hacks, to work on during the weekend will of course be free and open code and not unlikely a fair amount of things will be security related.

The event is two full days, with some kind of social thing happening on the Saturday evening and with final presentations on Sunday afternoon.

Hopefully we can use each others’ competences and cross-feed between our different communities to get inputs, feedback and good spirit into the targeted projects.

This event is number 2 since the OWAPS guys already had Community Hack #1 back in January 2010, but at that time FOSS-STHLM wasn’t involved.

We gather all info about this event at foss-sthlm.haxx.se/mote3.html.

owaspTommy-Nevtelen-FOSS_STHLM

curl vs libcurl

In my mini-series of articles A vs B, the time is up for curl vs libcurl.

For me, the differences are so very clear and obvious but I get a fair stream of questions from users and random people that I thought it was about time to make an effort to once and for all make a page with the facts stated. A fixed home for curl vs libcurl knowledge.

So I did. And now I mentioned it to you. Enjoy! If you have additional content you think belong there or if you think anything is unclear or wrong, don’t hesitate to let me know!

cURL

Daniel’s currency exchange is no more

For quite a number of years I maintained a little web service to provide currency exchange rates in a handy format and in a way that was friendly for machines and other machine-exchangers. My personal favorite feature was the “easy conversion” helper that would provide a “easy to calculate in head” formula for back and forth between two currencies based on their current rates. Like “multiply by 5 and divide by 2” etc.

This service goes all the way back to 1997 when I started to work on getting exchange rates downloaded as a service to the IRC bot I ran in #amiga on efnet (even before the split when ircnet was created). Back then I was primarily working on the IRC bot named Dancer. 1997 I started the work on a tool to fetch rates. The tool would become curl and the web site to access the rates was initially hosted by the company Frontec for which I worked back then.One dollar bill

The URL changed a few more times but it has been available at http://daniel.haxx.se/currency for the last few years until a few weeks ago. Well, technically the URL still works but the service does not.

So a few weeks ago the primary site I’ve scraped for this info changed their format and I decided to not play cat and mouse anymore. I was already bending the rules by not reading their terms of service as I feared I wouldn’t be allowed to use their data like this. Also, I really don’t have any use for this service myself so I decided to do myself a service and stop wasting spare time on one of these projects that don’t give me enough personal satisfaction. I’m sure that if there is a demand for such a service I now closed down, there will be someone else out there ready to fire it up and serve users.

So long, and thanks for all the currency exchange fun.

Rockbox devcon is now

This weekend, in Ghent Belgium, the annual Rockbox developers conference “devcon” is taking place. Unfortunately I’m not there myself this year, but I can get a little sense of the atmosphere by following the live stream. Click the image to get to it. Do note that the stream will only be alive during this weekend June 5-6 2010.

Rockbox Devcon 2010 live stream

Here’s the team that was present at Devcon, picture from petur’s comment:

rockbox-devcon2010-grouppic

roffit lives!

Many moons ago I created a little tool I named roffit. It is just a tiny perl script that converts a man page written in the nroff format to good-looking HTML. I should perhaps also add that I didn’t find any decent alternatives then so I wrote up my own version. I’ve been using it since in projects such as curl, c-ares and libssh2 to produce web versions of the docs.

It has just done its job and I haven’t had any needs to fiddle with it. The project page lists it as last modified in 2004, even though I actually moved it to a sourceforge CVS repo back in 2007.

Just a few days ago, I got emailed and was notified that Debian has it included as a package in the distribution and someone was annoyed on some particular flaws.

This resulted in a bunch of bugs getting submitted to the Debian bug tracker, I started up the brand new roffit-devel mailing list to easier host roffit discussions and I switched over the CVS repo to a git one on github.

If you like seeing man pages turned into web pages, consider joining up and help us improve this thing!

My talk Optimera Sthlm

30 minutes is a tricky period to fill with contents when you do a talk, and yesterday I did my best at confusing/informing the audience at the OPTIMERA STHLM conference in transport layer performance. Where time is spent or lost today in TCP, what to think about to get things to behave faster, that RTT is not getting better even though brandwidth is growing really fast these days and a little about some future technologies like WebSockets, SPDY, SCTP and MPTCP.

Note: this talk is entirely in Swedish.

My slides for this is also viewable with slideshare.net like this: