I want to add an extra prompt asking the user if they are sure they want to save the file, but only for files in certain "protected" directories. Assume I have a function `file-needs-protection-p` that takes a file name and returns t if the user should be queried before saving that file. How can I get Emacs to ask something like `"This file is protected. Are you sure you want to modify it?"` when the user tries to save such a file, and then make Emacs abort the save if the user answers no?

Hopefully there is some special hook somewhere where I can add a function that uses `yes-or-no-p`, and Emacs will abort the save if the function returns false?