Asking Root password etc.

I have ubuntu 12.04 lts operating system installed in my laptop. I need the software in C or C++ for the following: Whenever any file in the Operating system is read BY ANY COMMAND, I need the software to seek authentication of either login root, su root, login user1, login user2(Chice of 1 to 4 should be provided and after selecting 1 or 2 or 4, it should ask what are they i.e., login root and/or su root and/or login user1 and/or login user2) . When any one of the four correct password is provided then only the file should be read and further action(s) should be done. If a command requires reading of more than 1 file say n files, then n times authentication should be asked and done. I should be able to edit login root, su root, login user1, login user2 in the software itself. I need the source code of the above program and compilation procedure and execution procedure.