I actually cannot get enough information from doing that. Crucially, I need to be able to recognize whether two file descriptors point to the same open `file_struct`. (To be clear, this isn't the same as whether they're pointing to the same file path. I need to know when the two file descriptors are sharing the same cursor.) There is no way to do this using existing APIs, because there is nothing identifying a `struct file` besides the memory address of the struct. (The "open file IDs" I mention are hashes of the `file_struct` address.)

I did spend a lot of time trying to avoid writing a kernel module, and this was the only way I could find to do it :)