My XJ is leaking water into the cab

Hey everyone. So here is my issue. My recently purchased cherokee has an issue where it leaks water in from that rain channel that runs the length of the upper edge (you all know what I'm talking about right?) anyways, i pour water in it and it just seaps right through to the bottom and runs down the upper door jam and has started some substantial surface rust. It looks like that channel is just glued on or something. So i was wondering if the glue has a hole in it or something. Anyone else ever have this problem? any ideas on how to fix it? i can upload pics if you're all confused on what I'm asking. thanks!