Hi. I've looked a bit at the systemd code as compared to the elogind code. One of the major reasons that libsystemd0 cannot be used as a replacement for libelogind0 is that elogind does not have compatible cgroup naming. The systemd (and elogind) libraries do some operations over dbus. But other operations are done directly. For example to look and see what session a pid is in, the library will look at the cgroups of the pid. Similarly to see whether a particular pid belongs to a uid, it looks at the cgroup naming.
If you take a look at src/basic/cgroup-util.c in the elogind sources and take a look at what is #if 0'd you can see the naming differences. I don't know what would happen if you built a elogind that used systemd naming. I don't know what the next hurtle would be. --Sam
