Ressources documentaires pour Mandriva Linux et les Logiciels Libres

Billets libellés HAL

Oh time suspend your flying 2

Some days ago, I talk about the fact that some underlying technologies were changing too fast. I was mostly talking about HAL vs DeviceKit/libudev/… saga. Today I’ve discovered another one : PolicyKit vs polkit. Indeed once upon a time, someone consider that su/sudo/consolhelper mecanisms were not
sufficient. So they introduced a new Policy framework using DBUS and config in some XML files : this was PolicyKit. Most of the time, policyKit comes pre-configured, and so I’m pretty sure that few people know how to use it or customised it. Now it seems that after PolicyKit 0.9, PolicyKit will be replaced by … polkit-1.

I look at the reasons for PolicyKit drop, and franky, whereas I do agree, I still can’t understand why this could not have been avoided before ! Especially
theses ones :

  • make it easier to write backends that reads authorizations from a networked resource (such as a LDAP server)
  • possible to grant authorizations to Unix groups

Sorry, but theses 2 features are for me the most basics ones that you can ask for a policy framework ! Not being able to use Unix group to manage
authorizations, or not providing network based backends is IMHO an error when willing to consider seriously in the enterprise as a workstation environment … Windows does support this since at least … 2000 with the introduction of Active Directory. And even in a Domain Controller, we can do this too with poledit

At least now, we will be able to have the same features than at east Windows NT4 … That’s great !

Oh time suspend your flying

I do remember when less than 2 years ago we had to handle the HAL support in xorg.conf … This was painful as there were several issues :

  • HAL need to be started or else you may end up without mouse and keyboard
  • By default HAL setting up a US keyboard layout ( QWERTY )
  • There was the need to find a way to configure the keyboard layout, and HAL dev was reluctant to put this in the FDI files are users are not supposed to mess up with HAL fdi file
  • We end up putting keyboard layout to another file … /etc/sysconfig/keyboard

Now that everything is stable and most distribution integrate this well … please be aware of the fact that … Xorg will be dropping HAL support in Xorg 1.8. So at the end, Xorg will be using more platform specific code ( libudev, libdevinfo, … ) as neither DeviceKit or udisk will provide the previous HAL functionnality. To ease Xorg configuration, /etc/X11/xorg.conf.d will be also add to Xorg.

I do regret HAL as it was allowing to abstract the device detection and enumeration on Linux, thus allowing application dev to use higher level API instead of having to know low level details. However it’s true that HAL was having performances issues on large system, and many embedded products were not using HAL. I do hope however that this will be the last big change in Linux : there’s a need for a kind of stability in the platform !


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