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Name: Daniel Stenberg
Member since: 2000-05-10 09:34:05
Last Login: 2009-12-04 19:23:29

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Homepage: http://daniel.haxx.se/

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Good bye Rockbox

I’m officially not taking part in anything related to Rockbox anymore. I’ve unsubscribed and I’m out.

In the fall of 2001, my friend Linus and my brother Björn had both bought the portable Archos Player, a harddrive based mp3 player and slightly underwhelmed by its firmware decided they would have a go at trying to improve it. All three of us had been working with embedded systems for many years already and I was immediately attracted to the idea of reverse engineering this kind of device and try to improve it. It sounded like a blast to me.

In December 2001 we had the first test program actually running on the device and flashing a led. The first little step of what would become a rather big effort. We wrote a GPLed mp3 player firmware replacement, entirely from scratch without re-using any original parts. A full home-grown tiny multitasking operating system with a UI.

Fast-forwarding through history: we managed to get a really good firmware done for the early Archos players and we managed to move on to follow-up mp3 players too. After a decade or so, we supported well over 60 different mp3 player models and we played every music format known to man, we usually had better battery life than the original firmwares. We could run doom and we had a video player, a plugin system and a system full of crazy things.

We gathered large amounts of skilled and intelligent hackers from all over the world who contributed to make this possible. We had yearly meetups, or developer conferences, and we hung out on IRC every day of the week. I still hang out on our off-topic IRC channel!

Over time, smart phones emerged as the preferred devices people would use to play music while on the go. We ported Rockbox over to Android as an app, but our pixel-based UI was never really suitable for the flexible Android world and I also think that most contributors were more interested in hacking devices than writing Android apps. The app never really attracted many users or developers so while functional it never “took off”.

mp3 players are now already a thing of the past and will soon fall into the cave of forgotten old things our children will never even know or care about.

Developers and users of Rockbox have mostly moved on to other ventures. I too stopped actually contributing to the project several years ago but I was running build clients for a long while and I’ve kept being subscribed to the development mailing list. Until now. I’m now finally cutting off the last rope. Good bye Rockbox, it was fun while it lasted. I had a massive amount of great fun and I learned a lot while in the project.

Rockbox

Syndicated 2014-10-01 08:53:48 from daniel.haxx.se

A day in the curl project

cURLI maintain curl and lead the development there. This is how I spend my time an ordinary day in the project. Maybe I don’t do all of these things every single day, but sometimes I do and sometimes I just do a subset of them. I just want to give you a look into what I do and why I don’t add new stuff more often or faster… I spend about one to three hours on the project every day. Let me also stress that curl is a tiny little project in comparison with many other open source projects. I’m certainly not saying otherwise.

the new bug

Someone submits a new bug in the bug tracker or on one of the mailing lists. Most initial bug reports lack sufficient details so the first thing I do is ask for more info and possibly ask the submitter to try a recent version as very often we get bug reported on very old versions. Many bug reports take several demands for more info before the necessary details have been provided. I don’t really start to investigate a problem until I feel I have a sufficient amount of details. We’re a very small core team that acts on other people’s bugs.

the question by a newbie in the project

A new person shows up with a question. The question is usually similar to a FAQ entry or an example but not exactly. It deserves a proper response. This kind of question can often be answered by anyone, but also most people involved in the project don’t feel the need or “familiarity” to respond to such questions and therefore remain quiet.

the old mail I haven’t responded to yet

I want every serious email that reaches the mailing lists to get a response, so all mails that neither I nor anyone else responds to I keep around in my inbox and when I have idle time over I go back and catch up on old mails. Some of them can then of course result in a new bug or patch or whatever. Occasionally I have to resort to simply saving away the old mail without responding in order to catch up, just to cut the list of outstanding things to do a little.

the TODO list for my own sake, things I’d like to get working on

There are always things I really want to see done in the project, and I work on them far too little really. But every once in a while I ignore everything else in my life for a couple of hours and spend them on adding a new feature or fixing something I’ve been missing. Actual development of new features is a very small fraction of all time I spend on this project.

the list of open bug reports

I regularly revisit this list to see what I can do to push the open ones forward. Follow-up questions, deep dives into source code and specifications or just the sad realization that a particular issue won’t be fixed within the nearest time (year?) so that I close it as “future” and add the problem to our KNOWN_BUGS document. I strive to keep the bug list clean and only keep relevant bugs open. Those issues that are not reproducible, are left without the proper attention from the reporter or otherwise stall will get closed. In general I feel quite lonely as responder in the bug tracker…

the mailing list threads that are sort of dying but I do want some progress or feedback on

In my primary email inbox I usually keep ongoing threads around. Lots of discussions just silently stop getting more posts and thus slowly wither away further up the list to become forgotten and ignored. With some interval I go back to see if the posters are still around, if there’s any more feedback or whatever in order to figure out how to proceed with the subject. Very often this makes me get nothing at all back and instead I just save away the entire conversation thread, forget about it and move on.

the blog post I want to do about a recent change or fix I did I’d like to highlight

I try to explain some changes to the world in blog posts. Not all changes but the ones that are somehow noteworthy as they perhaps change the way things have been or introduce new fun features perhaps not that easily spotted. Of course all features are always documented etc, but sometimes I feel I need to put some extra attention on focus on things in a more free-form style. Or I just write about meta stuff, like this very posting.

the reviewing and merging of patches

One of the most important tasks I have is to review patches. I’m basically the only person in the project who volunteers to review patches against any angle or corner of the project. When people have spent time and effort and gallantly send the results of their labor our way in the best possible format (a patch!), the submitter deserves a good review and proper feedback. Also, paving the road for more patches is one of the best way to scale the project. Helping newcomers become productive is important.

Patches are preferably posted on the mailing lists but there’s also some coming in via pull requests on github and while I strongly discourage that (due to them not getting the same attention and possible scrutiny on the list like the others) I sometimes let them through anyway just to be smooth.

When the patch looks good (or sometimes good enough and I just edit some minor detail), I merge it.

the non-disclosed discussions about a potential security problem

We’re a small project with a wide reach and security problems can potentially have grave impact on users. We take security seriously, and we very often have at least one non-public discussion going on about a problem in curl that may have security implications. We then often work on phrasing security advisories, working down exactly which versions that are vulnerable, producing patches for at least the most recent ones of those affected versions and so on.

tame stackoverflow

stackoverflow.com has become almost like a wikipedia for source code and programming related issues (although it isn’t wiki), and that site is one of the primary referrers to curl’s web site these days. I tend to glance over the curl and libcurl related questions and offer my answers at times. If nothing else, it is good to help keeping the amount of disinformation at low levels.

I strongly disapprove of people filing bug reports on such places or even very detailed (lib)curl core questions that should’ve been asked on the curl-library list.

there are idle times too

Yeah. Not very often, but sometimes I actually just need a day off all this. Sometimes I just don’t find motivation or energy enough to dig into that terrible seldom-happening bug on a platform I’ve never seen personally. A project like this never ends. The same day we release a new release, we just reset our clocks and we’re back on improving curl, fixing bugs and cleaning up things for the next release. Forever and ever until the end of time.

keep-calm-and-improve-curl

Syndicated 2014-09-29 20:59:05 from daniel.haxx.se

Changing networks with Firefox running

Short recap: I work on network code for Mozilla. Bug 939318 is one of “mine” – yesterday I landed a fix (a patch series with 6 individual patches) for this and I wanted to explain what goodness that should (might?) come from this!

diffstat

diffstat reports this on the complete patch series:

29 files changed, 920 insertions(+), 162 deletions(-)

The change set can be seen in mozilla-central here. But I guess a proper description is easier for most…

The bouncy road to inclusion

This feature set and associated problems with it has been one of the most time consuming things I’ve developed in recent years, I mean in relation to the amount of actual code produced. I’ve had it “landed” in the mozilla-inbound tree five times and yanked out again before it landed correctly (within a few hours), every time of course reverted again because I had bugs remaining in there. The bugs in this have been really tricky with a whole bunch of timing-dependent and race-like problems and me being unfamiliar with a large part of the code base that I’m working on. It has been a highly frustrating journey during periods but I’d like to think that I’ve learned a lot about Firefox internals partly thanks to this resistance.

As I write this, it has not even been 24 hours since it got into m-c so there’s of course still a risk there’s an ugly bug or two left, but then I also hope to fix the pending problems without having to revert and re-apply the whole series…

Many ways to connect to networks

Firefox Nightly screenshotIn many network setups today, you get an environment and a network “experience” that is crafted for that particular place. For example you may connect to your work over a VPN where you get your company DNS and you can access sites and services you can’t even see when you connect from the wifi in your favorite coffee shop. The same thing goes for when you connect to that captive portal over wifi until you realize you used the wrong SSID and you switch over to the access point you were supposed to use.

For every one of these setups, you get different DHCP setups passed down and you get a new DNS server and so on.

These days laptop lids are getting closed (and the machine is put to sleep) at one place to be opened at a completely different location and rarely is the machine rebooted or the browser shut down.

Switching between networks

Switching from one of the networks to the next is of course something your operating system handles gracefully. You can even easily be connected to multiple ones simultaneously like if you have both an Ethernet card and wifi.

Enter browsers. Or in this case let’s be specific and talk about Firefox since this is what I work with and on. Firefox – like other browsers – will cache images, it will cache DNS responses, it maintains connections to sites a while even after use, it connects to some sites even before you “go there” and so on. All in the name of giving the users an as good and as fast experience as possible.

The combination of keeping things cached and alive, together with the fact that switching networks brings new perspectives and new “truths” offers challenges.

Realizing the situation is new

The changes are not at all mind-bending but are basically these three parts:

  1. Make sure that we detect network changes, even if just the set of available interfaces change. Send an event for this.
  2. Make sure the necessary parts of the code listens and understands this “network topology changed” event and acts on it accordingly
  3. Consider coming back from “sleep” to be a network changed event since we just cannot be sure of the network situation anymore.

The initial work has been made for Windows only but it allows us to smoothen out any rough edges before we continue and make more platforms support this.

The network changed event can be disabled by switching off the new “network.notify.changed” preference. If you do end up feeling a need for that, I really hope you file a bug explaining the details so that we can work on fixing it!

Act accordingly

So what is acting properly? What if the network changes in a way so that your active connections suddenly can’t be used anymore due to the new rules and routing and what not? We attack this problem like this: once we get a “network changed” event, we “allow” connections to prove that they are still alive and if not they’re torn down and re-setup when the user tries to reload or whatever. For plain old HTTP(S) this means just seeing if traffic arrives or can be sent off within N seconds, and for websockets, SPDY and HTTP2 connections it involves sending an actual ping frame and checking for a response.

The internal DNS cache was a bit tricky to handle. I initially just flushed all entries but that turned out nasty as I then also killed ongoing name resolves that caused errors to get returned. Now I instead added logic that flushes all the already resolved names and it makes names “in transit” to get resolved again so that they are done on the (potentially) new network that then can return different addresses for the same host name(s).

This should drastically reduce the situation that could happen before when Firefox would basically just freeze and not want to do any requests until you closed and restarted it. (Or waited long enough for other timeouts to trigger.)

The ‘N seconds’ waiting period above is actually 5 seconds by default and there’s a new preference called “network.http.network-changed.timeout” that can be altered at will to allow some experimentation regarding what the perfect interval truly is for you.

Firefox BallInitially on Windows only

My initial work has been limited to getting the changed event code done for the Windows back-end only (since the code that figures out if there’s news on the network setup is highly system specific), and now when this step has been taken the plan is to introduce the same back-end logic to the other platforms. The code that acts on the event is pretty much generic and is mostly in place already so it is now a matter of making sure the event can be generated everywhere.

My plan is to start on Firefox OS and then see if I can assist with the same thing in Firefox on Android. Then finally Linux and Mac.

I started on Windows since Windows is one of the platforms with the largest amount of Firefox users and thus one of the most prioritized ones.

More to do

There’s separate work going on for properly detecting captive portals. You know the annoying things hotels and airports for example tend to have to force you to do some login dance first before you are allowed to use the internet at that location. When such a captive portal is opened up, that should probably qualify as a network change – but it isn’t yet.

Syndicated 2014-09-26 06:24:39 from daniel.haxx.se

daniel.haxx.se week #3

I won’t keep posting every video update here, but I mostly wanted to mention that I’ve kept posting a weekly video over at youtube basically explaining what’s going on right now within my dearest projects. Mostly curl and some Firefox stuff.

This week: libcurl server cert verification API got a bashing at SEC-T, is HTTP for UDP a good idea? How about adding HTTP cache support to libcurl? HTTP/2 is getting deployed as we speak. Interesting curl bug when used by XBMC. The patch series for Firefox bug 939318 is improving slowly – will it ever land?