find-file-sudo.el

;; -*- Mode: Emacs-Lisp -*-

;; Tramp mode for transparent remote access... Pretending to load
;; partial-completion-mode so tramp will complete hostnames
;;(partial-completion-mode t)
(require 'tramp)

;; Tramp to open files owned by root (from EmacsWiki)
(defvar find-file-root-prefix
  (if (featurep 'xemacs)
      "/[sudo/root@localhost]"
    "/sudo:root@localhost:" )
  "*The filename prefix used to open a file with `find-file-root'.")

(defvar find-file-root-history nil
  "History list for files found using `find-file-root'.")

(defvar find-file-root-hook nil
  "Normal hook for functions to run after finding a \"root\" file.")

(defun find-file-root ()
  "*Open a file as the root user.
   Prepends `find-file-root-prefix' to the selected file name so that it
   maybe accessed via the corresponding tramp method."

  (interactive)
  (require 'tramp)
  (let* ( ;; We bind the variable `file-name-history' locally so we can
   	 ;; use a separate history list for "root" files.
   	 (file-name-history find-file-root-history)
   	 (name (or buffer-file-name default-directory))
   	 (tramp (and (tramp-tramp-file-p name)
   		     (tramp-dissect-file-name name)))
   	 path dir file)

    ;; If called from a "root" file, we need to fix up the path.
    (when tramp
      (setq path (tramp-file-name-localname tramp)
   	    dir (file-name-directory path)))

    (when (setq file (read-file-name "Find file (UID = 0): " dir path))
      (find-file (concat find-file-root-prefix file))
      ;; If this all succeeded save our new history list.
      (setq find-file-root-history file-name-history)
      ;; allow some user customization
      (run-hooks 'find-file-root-hook))))

(defface find-file-root-header-face
  '((t (:foreground "white" :background "red3")))
  "*Face use to display header-lines for files opened as root.")

(defun find-file-root-header-warning ()
  "*Display a warning in header line of the current buffer.
   This function is suitable to add to `find-file-root-hook'."
  (let* ((warning "WARNING: EDITING FILE AS ROOT!")
   	 (space (+ 6 (- (window-width) (length warning))))
   	 (bracket (make-string (/ space 2) ?-))
   	 (warning (concat bracket warning bracket)))
    (setq header-line-format
   	  (propertize  warning 'face 'find-file-root-header-face))))

;;(add-hook 'find-file-root-hook 'find-file-root-header-warning)
;; Using find-file-hook is better, I think. - rubikitch
(defun find-file-hook-root-header-warning ()
  (when (and buffer-file-name (string-match "root@localhost" buffer-file-name))
    (find-file-root-header-warning)))

(add-hook 'find-file-hook 'find-file-hook-root-header-warning)


(provide 'find-file-sudo)