Open a file with su/sudo inside Emacs

Question

Suppose I want to open a file in an existing Emacs session using su or sudo, without dropping down to a shell and doing sudoedit or

Answer 1

Not really an answer to the original question, but here's a helper function to make doing the tramp/sudo route a bit easier:

(defun sudo-find-file (file-name)
  "Like find file, but opens the file as root."
  (interactive "FSudo Find File: ")
  (let ((tramp-file-name (concat "/sudo::" (expand-file-name file-name))))
    (find-file tramp-file-name)))