System Bus Activation hits Fedora Rawhide

.. well, almost. Anyway, you can get packages here or wait until Rawhide opens again (it’s currently frozen for F8t1). Credit goes to Richard for finishing this work and getting it past Havoc. This is a really huge thing; it opens up a lot of possibilities for better desktop/OS integration.

Lots of pretty colors

To actually test the packages I wrote a simple test program and thought it might be useful to share it. First, you need a program that claims a name on the system bus. I just copied the one from the dbus-python repository and modified it slightly. You can see it here.

Second, as with any service on the system message bus (as opposed to the session bus which has different security characteristics) you need a file in /etc/dbus-1/system.d. Mine is named dk.fubar.Test.conf (but note that any unique file name ending in .conf will do) and is pretty much run-of-the-mill standard stuff and shouldn’t be a surprise if you’re familiar with services on the system bus. It looks like this.

Finally, for system bus activation to work you simply need to put a service file in /usr/share/dbus-1/system-services. Mine is named dk.fubar.Test.service (again, any unique name ending in .service will do) and looks like this:

[D-BUS Service]
Name=dk.fubar.Test
Exec=/usr/sbin/dbus-sysbus-test.py
User=root

and that’s it! Provided you installed everything correctly (there’s a cheesy Makefile to do this) things should Just Work(tm) and the following command should print

$ dbus-send --system --print-reply --dest=dk.fubar.Test /SomeObject dk.fubar.Test.SampleInterface.HelloWorld string:foo
method return sender=:1.517 -> dest=:1.516 reply_serial=2
array [
string "Hello"
string " from example-service.py"
string "with unique name"
string ":1.517"
]

If your service is capable of operating correctly when running as an unprivileged system user (e.g. ftp or whatever) instead of root (think least privilege), simply change the user mentioned in both the .service and .conf files.

No more polling

I just committed code to hal to take advantage of asynchronous change notification events originating from SATA AN capable drives. This means we can avoid polling the drive and this should result in fewer wakeups in libata. This also opens the opportunity for the drive itself to go into a deeper sleep state when it’s not used. So all in all this should improve laptop battery life. I haven’t tried this on a laptop just yet, but when I find a suitable one I’m sure PowerTOP will tell me.

I took this while testing this GPS receiver. Click to see where to get good coffee.

Credit goes to Kristen Carlson Accardi from Intel. She did the kernel bits, sent me a SATA AN capable drive and pointed me in the right direction. To try this out, you will need a recent kernel and also some patches not yet in Linus’ tree. See RH #204969 for details. I’m hoping this will make it into Fedora 8; the hal bits will for sure; for the kernel bits I suppose asking davej is in order.

PolicyKit release

Late last night I finally made a PolicyKit release. It’s almost ready for prime time; wait a month for 0.4 to get out and I should be able to maintain a stable API.

PolicyKit in action

With Richard’s great work on D-Bus system bus activation it looks like we’re soon going to have nice upstream frameworks for enabling the desktop to do privileged operations in a hopefully sane way. Instead of having each and every distribution on the planet write their own configuration tools. I, for one, really wants to see some effort of merging such things into upstream GNOME and KDE as far as possible.

Interwebs

Normally I’m not opposed to what our new web overlords are serving us; you know; social networks and the ability to see what past and present, uh, peers are up to… but sometimes it’s just TMI - Maybe I just need to use the Interwebs less

i’m in ur RAID, striping ur disks all the way to CA

Recently I acquired a pair of 500GB USB2 hard disks that I use in a RAID-1 configuration (on two different host controllers!); you know, to store my photos and other important, uh, stuff. I had some spare time this weekend to look at fd.o #6426 so I wrote a small patch to teach HAL about Linux software RAID.

RAID rebuilding

I also whipped up patch to gnome-device-manager such as to show the new properties introduced including whether an array is running in degraded mode or is being rebuilt. It’s pretty spiffy.

All that this code is doing right now is basically just listening to kernel events (via udev and priority data on /proc/mdstat) and then representing the RAID arrays as HAL drives and volumes. It’s spiffy because the RAID drive inherits things like storage.hotpluggable from the physical components (e.g. the two USB hard disks) so in my case the RAID array simply appears in Nautilus and is totally mountable just like a regular external drive. Works out of the box. Desktop integration++. However, we can do a bit better so for GNOME 2.20 I’ll be writing some patches to gnome-vfs and gvfs. You know, to use the new HAL properties to choose some helpful icons and icon captions.

Going forward, there needs to be some way of assembling and disassembling RAID arrays; hot-adding components to degraded arrays and so on and so on. Probably neither Nautilus nor gnome-device-manager is the right approach here. And there will probably be some sort of auto-assembly happening at the system-wide level anyway, need to sort that out with Kay (the udev maintainer) and also talk to various distro maintainers too. It’s also probably also time to revive my never properly announced GNOME Disk Utility project. Actually, that’s one reason that I split the Device Manager into a shell and library component; right now the shell is around 1200 lines (compared to 4000+ for the library) and there’s no reason that the Disk Utility shell would be a lot bigger. Plus it’s always awesome to put pretty UI on top of useful infrastructure.

Tomorrow I’m leaving for The Golden State to go the Red Hat summit, then hang out with Kay Sievers and finish off the west-coast invasion with FreedomHEC. The next two weeks are going to be busy.

Battery Recall^WExchange

Just found, via the interwebs, that the battery in my 15″ Macbook Pro was recalled^Weligible for exchange almost a year ago although not for safety risks, merely because “… batteries supplied to Apple do not meet our high standards for battery performance.” [sic]. So that’s something. Anyway, since this is useful information, I wanted to add information to hal-info such that other Macbook Pro users would benefit as well. By getting spammed with a popup like this

Useful feature in g-p-m

But as it turns out this data is not easily available


$ cat /proc/acpi/battery/BAT0/info
present: yes
design capacity: 55000 mWh
last full capacity: 47150 mWh
battery technology: rechargeable
design voltage: 10800 mV
design capacity warning: 250 mWh
design capacity low: 100 mWh
capacity granularity 1: 10 mWh
capacity granularity 2: 10 mWh
model number: ASMB012
serial number:
battery type: LION012
OEM info: SMPN012


meaning it’s hard to match on anything sensible from the fdi file. Maybe this is because it’s a Smart Battery? FWIW, I can see that the sbs driver is loaded. Lazyweb, please help - as comments on my blog are busted, please provide answers personally to me or, preferably, the hal list (requires subscription).

Btw, I couldn’t find this information by poking around in Mac OS X either… but it must be there; I mean, normal non-smart batteries record make, model and serial numbers just fine via ACPI. That’s what we use to tag other recalled battery units. So I’m sure it’s possible to get at. And if Apple wanted, they could easily have similar mechanisms for displaying notifications similar to the ones we have in GNOME. But I can understand it would hurt their bottom line. I guess.. this is one interesting aspect of getting your OS from the same vendor as where you get your hardware.

Anyway, I filled out the form and a new battery is on it’s way. I guess, uh, thanks Apple. Just wish you had notified me earlier and I wouldn’t have to find out this way .

Update: I suppose this isn’t technically a Product Recall; Apple specifically uses the word Exchange instead. I guess, from a legal point of view at least, there’s a difference. To me, as a consumer, it’s doesn’t make huge difference however… hmm.. maybe we need to add a new property info.is_eligible_for_exchange to the HAL spec to avoid using the word “recall” at all in such situations. I mean, to, uh, cover our collective asses from angry hardware vendors.

Native languages and poisonous people

I think, over the past 3.5 years I’ve been working on free software, I have sent more than 5,000 mails, all in English, to various mailing lists, most of them with more than a few hundred subscribers. It’s always a bit weird (even after living in Massachusetts for more than 2.5 years) to use your second language and I believe it will stay that way the rest of my life. Which is fine and all.

Sketchy Dane

In general, I’ve found that native English speakers are very nice to non-native English speakers. In stark contrast, for example, are natives of my own country Denmark; whenever a foreigner attempts to speak Danish everything becomes a bit weird. One common thing is that the native Danes try to switch to conversation to English because it makes them less uncomfortable. I guess there are many reasons for this difference of behavior; first, Danish is a small, insignificant (and dying) language, most people speak English anyway and not a lot of native English speakers have a second language at all. But it’s also a cultural thing. In particular, I find that it’s very easy to live among the Americans; they’re friendly (actually, I jokingly tend to say “it’s like living with the smurfs”; many, not all though, people here are just more optimistic about the future than in Denmark and the EU.). The fact that English is a second language have never been an issue for me at all.

Sketchy German

Until today. I guess there’s a first time for everything, the topic of my native language came up on the Fedora live cd mailing list just recently. Response here. Time to watch How Open Source Projects Survive Poisonous People (And You Can Too) again I suppose.

The whole thing just makes me a little sad inside.