Shares fully working! Slightly slow, but usable. Clipboardy stuff too.
I’ve now fixed most of the bugs in the guest additions, to the point that what’s done so far is mostly usable - the only major bugs remaining are some random crashes in VBoxService that I’ve not been able to reproduce, and an inability to drag icons when mouse pointer integration is enabled. (Thanks to kallisti5 for finding both of these.) I also have replaced VBoxApp (which currently handles clipboard sharing) with VBoxTray, a replicant which serves the same purpose but can be autoloaded by Deskbar.
This is a companion discussion topic for the original entry at https://www.haiku-os.org/blog/scgtrp/2011-07-15_vbox_guest_additions_midterm_status_report/