Category Archives: Open Source

Open Source, Free Software, and similar

cURL and libcurl, Network, Open Source

murl for extended curlness

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I’m a firm believer in the old unix mantra of letting each tool do its job and do it well, and pass on the rest of the work to the next tool. I’ve always stated that curl should remain this way and that it should remain within its defined walls and not try to do everything.

But time passes and more and more ideas are thrown up in the air, or in some cases directly at me, and the list of things that we could do but don’t due to this philosophical limit of remaining focused has grown. It currently includes at least:

  • metalink support
  • recursive HTML downloads
  • recursive/wildcard FTP transfers
  • bittorrent support
  • automatic proxy configuration
  • simultaneous/parallel download support

Educated readers of course immediately detect that this list (if implemented) would make a tool that basically does what wget already does (and a lot more) and I’ve explicitly said for a decade that curl is not a wget clone. Maybe it is time for us (me?) to reevaluate that sentiment – at least in some sense.

I don’t want to sacrifice the concepts that have worked so fine for curl under so many years, so I’m still firmly against stuffing all this into curl (or libcurl). That simply will not happen with me at the wheel.

A much more interesting alternative would be to instead start working on a second tool within the curl project: murl. A tool that does basically everything that curl already does, but also opens the doors for adding just about everything else we can cram in and that is still related to data transfers. That would include, but not be restricted to, all the fancy stuff mentioned in the list above!

No the name murl is not set in stone, nor is this whole idea anything but plain and early thoughts thrown out at this point so it may or may not actually take off. It will probably depend on if I get support and help from fellow hackers to get started and moving along.

cURL

cURL and libcurl, Security

curl 7.19.4

curl and libcurl 7.19.4 has just been released! This time I think the perhaps most notable fix is the CVS-2009-0037 security fix which this release addresses. A little over 600 days passed since the previous vulnerability was announced.

Other than that major event, there are a bunch of interesting changes in this release:

  • Added CURLOPT_NOPROXY and the corresponding –noproxy
  • the OpenSSL-specific code disables TICKET (rfc5077) which is enabled by default in openssl 0.9.8j
  • Added CURLOPT_TFTP_BLKSIZE
  • Added CURLOPT_SOCKS5_GSSAPI_SERVICE and CURLOPT_SOCKS5_GSSAPI_NEC – with the corresponding curl options –socks5-gssapi-service and –socks5-gssapi-nec
  • Improved IPv6 support when built with with c-ares >= 1.6.1
  • Added CURLPROXY_HTTP_1_0 and –proxy1.0
  • Added docs/libcurl/symbols-in-versions
  • Added CURLINFO_CONDITION_UNMET
  • Added support for Digest and NTLM authentication using GnuTLS
  • CURLOPT_FTP_CREATE_MISSING_DIRS can now be set to 2 to retry the CWD even when MKD fails
  • GnuTLS initing moved to curl_global_init()
  • Added CURLOPT_REDIR_PROTOCOLS and CURLOPT_PROTOCOLS

We also did at least 15 documented bugfixes in this release and 25 people are credited for their help to make it happen.

Open Source, Technology

A stream of streamings

I’m a last.fm fan. I love its ability to not only stream music without needing a dedicated client installed (yes a flash application I think suits a purpose) and I think it’s ability to provide music I might also like is amazingly nice. I’m a “random it all” kind of guy when I listen to my local music collection in most situations as well. It is not specifly well suited for listening on exact the songs you want, as if you select a specific song it won’t even play the full-length version of it.

Lately there’s been a lot of buzz in Swedish tech media about spotify, which is a similar idea (at the moment still an on invitation-only thing in Sweden). They stream music, but only to a proprietary Windows or Mac client and currently they offer free listening with ads (embedded in the audio and visible in the client) or 99 SEK (== 9 Euros == 11 USD) per month. The client is highly focused on specific songs or artists and it has nothing in the way of “random artitists I generally like and similar ones”. I’m not too thrilled.

Spotify offers its service in several places, and I hear in the UK it’s not even invitation-only (which of course is useful for the more forward-thinking hacking kind of guys who thus use a UK based proxy to reach them). There’s however no sign of a Linux client. We’re forced to run their windows client with Wine.

I’ve gotten the impression that Pandora is a similar concept to play with if you happen to be based in the US. I’m in Sweden and Pandora just shows me a “We are deeply, deeply sorry to say that due to licensing constraints, we can no longer allow access to Pandora for listeners located outside of the U.S.”

The other day despotify.se showed up. A bunch of clever hackers reverse engineered the Spotify protocol and stream and offer a full unofficial open sourced ncurses/libvorbis/pulse-audio/gstreamer/expat/zlib/openssl-based player! Reading the code shows that these guys certainly had to crack some hard nuts, but the activity in their IRC channel seems fierce and the code is rather clean so I expect it to turn out to eventually become a fine player if Spotify just doesn’t decide to play hard ball with them. Unfortunately, despotify hasn’t yet been able to produce a single sound for me since it has just died on assert()s on basically any attempts I’ve tried. The interface is also a bit… strange and not the easiest to figure out. (It should be noted that the despotify client still requires you who have an actual spotify account.)

It’ll be interesting to see how Spotify, or perhaps the big media companies owning all the music rights, will act on this initiative. This client does open up abilities for new fancy features. How about ripping the stream? How about re-distributing the stream like as a proxy? And of course it being open, it does open up for adding features I want to add.

Update: just hours after I posted this, Spotify closed access to their service using the despotify client as long as you’re not a “premium” (paying) user…

cURL and libcurl

Saying lib out loud

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Not being a native English speaker, I’ve always pronounced libcurl with a ‘lib’ part as if it was part of ‘liberty’, and ‘curl’ with a K sound and ending with ‘earl’. I don’t know of any Swedes who would not pronounce ‘lib’ like that, but when speaking Swedish we’re of course highly influenced by other things so it’s not really relevant.

It wasn’t until I got on FLOSS Weekly that I fully realized that some English speakers would actually pronounce the ‘lib’ part as the first syllable of ‘library’ and that does make sense considering lib is short for library.

But libcurl is just a smaller player here. How do you English speakers pronounce libc? libxml? libgcc?

And yes, this is another one of those really important issues in life. Almost as important as how to close parenthetical expressions with emoticons!


Rockbox

Rockbox USB – A Long Journey

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The road to get a fully working and enabled mass-storage USB stack in Rockbox has been long and bumpy.

Bridge-Chip

Back in the early days of mp3 players, they all had bridge-chips which basically meant that the entire USB handling was handled by a dedicated chip that also “took control” of the hard drive (right, most of the interesting players used hard drives initially) so Rockbox didn’t have to do much except hand over control, show something nice on the screen in the mean time and then when the plug was pulled, regain control of the drive again and continue working.

But similar to how early players used dedicated HW-solutions to do music playback and then ditched that for pure CPU-powered solutions, the HW-solutions for USB also died out and all recent models do USB in software.

Research

The PortalPlayer chips being notorious for their complete lack of public docs were more or less considered impossibly hard to get USB working on by us. Until MrH came along 2006 and figured out that the USB parts of the PP5024 chip (used in the sansa e200v1 models) was identical to the USB core used by Freescale’s imx31 chip and there are public docs available for that.

Software Stack

The first step towards a software USB stack for Rockbox was taken in the 2007 gsoc, when Christian “austriancoder” Gmeiner took on the task. He went for a Linux-kernel inspired and quite ambitious approach that at the end of the gsoc project still didn’t quite work. The plan was at that point to primarily write a driver for the Sandisk Sansa e200 series, and secondary for other PortalPlayer based targets (such as ipods etc).

Made Working

Enter Björn “Zagor” Stenberg who had a much more minimalistic approach. Not being pleased with the “big” approach Christian had provided, the existing code was simply cut out and replaced with the new leaner version. Focus was then to get something small and simple to work, and then add fancier layers or features later on instead of providing the architecture for that already from the start. The stack started to partially work for mass-storage.

Not Yet Stable

USB wizard Frank Gevaerts joined the effort and worked fiercely on the thing and not only did he bring USB serial support (that does enable things like logf() support to debug rockbox) he also made the mass storage support almost reliable. The non-existing docs for the hardware made the remaining few flaws very hard to catch and the development of the stack stood still at this point for a great while.

Meanwhile, the USB stack could successfully be used on various new (in the Rockbox sense, these models are no longer new on the mp3 player market) targets like the Toshiba Gigabeat S and the Onda series etc. Parts of the Cowon D2 reverse engineering was greatly enhanced thanks to the USB stack as figuring out the FTL is even more tricky without a fine way to get data over to the host PC. All this proved that the stack itself worked nicely but that there were target-specific inits or setups that were missing for the PortalPlayer targets.

Of course the other new targets were not PortalPlayer based so it took efforts from clueful hackers like Vitja Makarov to implement the hardware driver for the TCC chips and Maurus Cuelenaere who did the driver for the Onda.

Stable?

Now, in 2009 our reverse engineering hero Boris “dreamlayers” Gjenero banged his head against the problem and by doing really nice disassembly he figured out previously not done initiation sequences. These have now been committed to the Rockbox SVN respository, and the early tests of this are very promising showing the mass storage support to be very close to get supported “out of the box” on the PortalPlayer 5022 based targets now. The PP5020 ones still seem unstable, and we have no support on the PP5002 ones.

If things just proceed this fine, we’ll be able to ship Rockbox’s own USB stack by default in the upcoming 3.2 release!

Commit

At Wed, 25 Feb 2009 23:40:15 +0100, the USB code was enabled in the SVN code: “Enable USB mass storage on PP5020, PP5022 and PP5024 targets”

Rockbox

Updates: this post was updated several times to gain accuracy and truths pointed out to me by Dave Chapman, Björn Stenberg, Frank Gevaerts, Jens Arnold and others. Thanks!

Open Source

Project is Standard now

I fell over a (warning: Swedish!) article on the Swedish idg.se site describing the nominees for the yearly award “Guldmusen” (“the golden mouse”). One of them is this year the highly deserving Adam Dunkel, originator of among other things the very cool lwip (light weight IP) open source project.

However, in both articles on IDG that’s not how lwip is described. It is instead claimed to be “an unofficial world standard”.

“world standard” huh? Yes I admit that makes it sound quite a few notches better than “well-used and appreciated open source project”.

But lwip is an TCP/IP stack. A very small one. How can that be a standard, even if you call it an unofficial one?

idg.se continues to be rediculed by me and my friends and the reasons are silly things like this. Let’s hope they continue to amuse us for a long time to come! 🙂

Rockbox

Blame game

I’ve mentioned the fancy distributed build system of Rockbox before, and now it just got even fancier as I’ve introduced a “blame” script that sends a mail to the commit mailing list (that gets mailed with a diff of every single commit) every time one or more builds in the automatic system show up red in the build table. Red builds are for errors (as opposed to yellow for just warnings or green for OK)…

The mail simply mentions that the builds are now red and who did the commit(s) that was included in the failing build. Due to the nature of it, it can be one or more committers and in fact there can be more commits than one from any of them. It’ll help us get alerted about the problems, and hopefully get them fixed again a little faster.

Rockbox

Open Source

Open source personal

I participate in a range of different open source projects. Of course I spend more time on some of them and only a very little time in most of them, but I’m currently listed as member of 18 projects on sourceforge and 16 on ohloh and I can easily figure out a bunch more than aren’t listed on either of those sites.

I’m just the kind of guy who tend to actually get the code and write up a patch for problems, and in fact also in many cases I’ll write an fresh application and publish it openly for the world (not that my typical programs get any particularly large audience but still). I’m not saying everyone has to be like this, I’m just describing me here.

It seems this is a troublesome concept for people to grasp.

I get a large amount of private mail where people talk about “your project” (as in a single one that I am supposed to understand which one they’re referring to) and just about all open source-related interview/questionnaire things I’ve filled in tend to assume My One Single Project. In the first case I can often guess which one they refer to by the phrasing of the mail, and in the second case I tend to answer for the project I’m involved the most in.

So I get this feed of private emails on projects I participate in, but I don’t like private emails about open source projects when people request and expect free support and help. If they want free support, I expect the people to post the questions publicly and open to allow others to reply and read both the question and the subsequent answer online, right there at the time they’re asked but also much later when searching for help on the same subject as then the answers will be around in mailing list archives etc.

These days I have a blanket reply form that I bounce back when I get private support mails and I will admit that most people respect that after having been told about the situation. Every now and then of course I get a violent refusal for sympathy and instead I get to learn I’m an arrogant bastard. This is also related to the fact that:

We (Haxx) run and offer commercial support around curl and libcurl, and for that purpose we have a dedicated support email address. Mail there if you’re willing to pay for support. That’s actually quite clearly spelled out everywhere where that address is displayed, but yet people seem to find that a good place to mail random questions and bug reports. Just today I got a very upset mail response after I mentioned the “paid support” part of the deal there expecting us (me?) to instantly fix bugs regardless since I’ve been told about them per email…

All in all, I’m not really complaining since I’m generally getting along fine with everyone and stuff around this.

Just everyone try to keep things apart: the projects, the people and the companies. They’re sometimes intertwined but sometimes not.