On Wed, Feb 18, 2009 at 5:37 PM, Colin Walters <walters(a)verbum.org> wrote:
Changing the login system has a *huge*
impact on how everything works and could easily result in confusing
problems higher up the stack.
Just to give a concrete example, how GDM uses PAM is highly
nontrivial, involving separate processes because of PAM's
ill-specified nature among other things. GDM also interacts with
various complex cases like smartcards that in turn involve other
system daemons. There is quite a bit happening inside GDM/PAM even on
a default desktop that may not be obvious, such as how gnome-keyring
saves your password to unlock the keyring. How gnome-keyring works
depends on various bits of infrastructure including dbus (this is a
tricky issue). NetworkManager in turn depends on gnome-keyring.
So yes, swapping out the login manager could quite easily result in
not being able to log in to your WPA network. It turns out an
operating system is a very complex thing, and we have plenty enough
bugs without people trying to replace parts of it without coordinating
with consumers higher up the stack.
Anyways...back to those bugs.