Ksplice user space equivalent?
 

Okay, so I've seen ksplice, and it's remarkably impressive. My impression is that they have even overcome the prior limitation of only editing code (not data structures).

So my question is this - is there an equivalent technology for userspace? Anything that can runtime-patch a daemon? Or even a library to support this? I have no particular use-case in mind other than the idea that such a capability would be very cool for the daemons I write.

Thanks!