-;;; epa-file.el --- the EasyPG Assistant hooks for transparent file encryption
+;;; epa-file.el --- the EasyPG Assistant, transparent file encryption
;; Copyright (C) 2006 Daiki Ueno
;; Author: Daiki Ueno <ueno@unixuser.org>
(require 'epa)
-(defgroup 'epa-file
+(defgroup epa-file nil
"The EasyPG Assistant hooks for transparent file encryption"
:group 'epa)
-(defcustom epa-file-name-regexp "\\.gpg\\'"
- "Regexp which matches filenames to be encrypted with GnuPG."
+(defun epa-file--file-name-regexp-set (variable value)
+ (set-default variable value)
+ (if (fboundp 'epa-file-name-regexp-update)
+ (epa-file-name-regexp-update)))
+
+(defcustom epa-file-name-regexp "\\.gpg\\(~\\|\\.~[0-9]+~\\)?\\'"
+ "Regexp which matches filenames to be encrypted with GnuPG.
+
+If you set this outside Custom while epa-file is already enabled, you
+have to call `epa-file-name-regexp-update' after setting it to
+properly update file-name-handler-alist. Setting this through Custom
+does that automatically."
:type 'regexp
+ :group 'epa-file
+ :set 'epa-file--file-name-regexp-set)
+
+(defcustom epa-file-cache-passphrase-for-symmetric-encryption nil
+ "If non-nil, cache passphrase for symmetric encryption."
+ :type 'boolean
+ :group 'epa-file)
+
+(defcustom epa-file-inhibit-auto-save t
+ "If non-nil, disable auto-saving when opening an encrypted file."
+ :type 'boolean
+ :group 'epa-file)
+
+(defcustom epa-file-select-keys nil
+ "If non-nil, always asks user to select recipients."
+ :type 'boolean
:group 'epa-file)
-
-(defvar epa-file nil)
-(defun epa-find-file ()
- (when (string-match epa-file-name-regexp (buffer-file-name))
- (if (= (buffer-size) 0)
+(defvar epa-file-encrypt-to nil
+ "*Recipient(s) used for encrypting files.
+May either be a string or a list of strings.")
+
+;;;###autoload
+(put 'epa-file-encrypt-to 'safe-local-variable
+ (lambda (val)
+ (or (stringp val)
+ (and (listp val)
+ (catch 'safe
+ (mapc (lambda (elt)
+ (unless (stringp elt)
+ (throw 'safe nil)))
+ val)
+ t)))))
+
+;;;###autoload
+(put 'epa-file-encrypt-to 'permanent-local t)
+
+(defvar epa-file-handler
+ (cons epa-file-name-regexp 'epa-file-handler))
+
+(defvar epa-file-passphrase-alist nil)
+
+(eval-and-compile
+ (if (fboundp 'encode-coding-string)
+ (defalias 'epa-file--encode-coding-string 'encode-coding-string)
+ (defalias 'epa-file--encode-coding-string 'identity)))
+
+(eval-and-compile
+ (if (fboundp 'decode-coding-string)
+ (defalias 'epa-file--decode-coding-string 'decode-coding-string)
+ (defalias 'epa-file--decode-coding-string 'identity)))
+
+(defun epa-file-name-regexp-update ()
+ (interactive)
+ (unless (equal (car epa-file-handler) epa-file-name-regexp)
+ (setcar epa-file-handler epa-file-name-regexp)))
+
+(defun epa-file-passphrase-callback-function (context key-id file)
+ (if (and epa-file-cache-passphrase-for-symmetric-encryption
+ (eq key-id 'SYM))
+ (let ((entry (assoc file epa-file-passphrase-alist))
+ passphrase)
+ (or (copy-sequence (cdr entry))
+ (progn
+ (unless entry
+ (setq entry (list file)
+ epa-file-passphrase-alist (cons entry
+ epa-file-passphrase-alist)))
+ (setq passphrase (epa-passphrase-callback-function context
+ key-id nil))
+ (setcdr entry (copy-sequence passphrase))
+ passphrase)))
+ (epa-passphrase-callback-function context key-id nil)))
+
+(defun epa-file-handler (operation &rest args)
+ (save-match-data
+ (let ((op (get operation 'epa-file)))
+ (if op
+ (apply op args)
+ (epa-file-run-real-handler operation args)))))
+
+(defun epa-file-run-real-handler (operation args)
+ (let ((inhibit-file-name-handlers
+ (cons 'epa-file-handler
+ (and (eq inhibit-file-name-operation operation)
+ inhibit-file-name-handlers)))
+ (inhibit-file-name-operation operation))
+ (apply operation args)))
+
+(defun epa-file-decode-and-insert (string file visit beg end replace)
+ (if (fboundp 'decode-coding-inserted-region)
+ (save-restriction
+ (narrow-to-region (point) (point))
+ (let ((multibyte enable-multibyte-characters))
+ (set-buffer-multibyte nil)
+ (insert string)
+ (set-buffer-multibyte multibyte)
+ (decode-coding-inserted-region
+ (point-min) (point-max)
+ (substring file 0 (string-match epa-file-name-regexp file))
+ visit beg end replace)))
+ (insert (epa-file--decode-coding-string string (or coding-system-for-read
+ 'undecided)))))
+
+(defvar last-coding-system-used)
+(defun epa-file-insert-file-contents (file &optional visit beg end replace)
+ (barf-if-buffer-read-only)
+ (if (and visit (or beg end))
+ (error "Attempt to visit less than an entire file"))
+ (setq file (expand-file-name file))
+ (let* ((local-copy
+ (condition-case inl
+ (epa-file-run-real-handler #'file-local-copy (list file))
+ (error)))
+ (local-file (or local-copy file))
+ (context (epg-make-context))
+ string length entry)
+ (if visit
+ (setq buffer-file-name file))
+ (epg-context-set-passphrase-callback
+ context
+ (cons #'epa-file-passphrase-callback-function
+ local-file))
+ (epg-context-set-progress-callback context
+ #'epa-progress-callback-function)
+ (unwind-protect
(progn
- (set-auto-mode)
- (hack-local-variables)
- (auto-save-mode nil))
- (goto-char (point-min))
- (insert (epg-decrypt-file (epg-make-context)
- (expand-file-name (buffer-file-name))
- nil))
- (delete-region (point) (point-max)))
- (make-local-variable 'epa-file)
- (setq epa-file (buffer-file-name))))
-
-(defun epa-write-file ()
- (when epa-file
- (write-region
- (epg-encrypt-string
- (epg-make-context)
- (buffer-string)
- (mapcar (lambda (key)
- (epg-sub-key-id
- (car (epg-key-sub-key-list key))))
- (epa-select-keys
- "Select recipents for encryption.
+ (if replace
+ (goto-char (point-min)))
+ (condition-case error
+ (setq string (epg-decrypt-file context local-file nil))
+ (error
+ (if (setq entry (assoc file epa-file-passphrase-alist))
+ (setcdr entry nil))
+ (signal 'file-error
+ (cons "Opening input file" (cdr error)))))
+ (make-local-variable 'epa-file-encrypt-to)
+ (setq epa-file-encrypt-to
+ (mapcar #'car (epg-context-result-for context 'encrypted-to)))
+ (if (or beg end)
+ (setq string (substring string (or beg 0) end)))
+ (save-excursion
+ (save-restriction
+ (narrow-to-region (point) (point))
+ (epa-file-decode-and-insert string file visit beg end replace)
+ (setq length (- (point-max) (point-min))))
+ (if replace
+ (delete-region (point) (point-max)))))
+ (if (and local-copy
+ (file-exists-p local-copy))
+ (delete-file local-copy)))
+ (list file length)))
+(put 'insert-file-contents 'epa-file 'epa-file-insert-file-contents)
+
+(defun epa-file-write-region (start end file &optional append visit lockname
+ mustbenew)
+ (if append
+ (error "Can't append to the file."))
+ (setq file (expand-file-name file))
+ (let* ((coding-system (or coding-system-for-write
+ (if (fboundp 'select-safe-coding-system)
+ ;; This is needed since Emacs 22 has
+ ;; no-conversion setting for *.gpg in
+ ;; `auto-coding-alist'.
+ (let ((buffer-file-name
+ (file-name-sans-extension file)))
+ (select-safe-coding-system
+ (point-min) (point-max)))
+ buffer-file-coding-system)))
+ (context (epg-make-context))
+ (coding-system-for-write 'binary)
+ string entry
+ (recipients
+ (cond
+ ((listp epa-file-encrypt-to) epa-file-encrypt-to)
+ ((stringp epa-file-encrypt-to) (list epa-file-encrypt-to)))))
+ (epg-context-set-passphrase-callback
+ context
+ (cons #'epa-file-passphrase-callback-function
+ file))
+ (epg-context-set-progress-callback context
+ #'epa-progress-callback-function)
+ (epg-context-set-armor context epa-armor)
+ (condition-case error
+ (setq string
+ (epg-encrypt-string
+ context
+ (if (stringp start)
+ (epa-file--encode-coding-string start coding-system)
+ (epa-file--encode-coding-string (buffer-substring start end)
+ coding-system))
+ (if (or epa-file-select-keys
+ (not (local-variable-p 'epa-file-encrypt-to
+ (current-buffer))))
+ (epa-select-keys
+ context
+ "Select recipents for encryption.
+If no one is selected, symmetric encryption will be performed. "
+ recipients)
+ (if epa-file-encrypt-to
+ (epg-list-keys context recipients)))))
+ (error
+ (if (setq entry (assoc file epa-file-passphrase-alist))
+ (setcdr entry nil))
+ (signal 'file-error (cons "Opening output file" (cdr error)))))
+ (epa-file-run-real-handler
+ #'write-region
+ (list string nil file append visit lockname mustbenew))
+ (if (boundp 'last-coding-system-used)
+ (setq last-coding-system-used coding-system))
+ (if (eq visit t)
+ (progn
+ (setq buffer-file-name file)
+ (set-visited-file-modtime))
+ (if (stringp visit)
+ (progn
+ (set-visited-file-modtime)
+ (setq buffer-file-name visit))))
+ (if (or (eq visit t)
+ (eq visit nil)
+ (stringp visit))
+ (message "Wrote %s" buffer-file-name))))
+(put 'write-region 'epa-file 'epa-file-write-region)
+
+(defun epa-file-find-file-hook ()
+ (if (and buffer-file-name
+ (string-match epa-file-name-regexp buffer-file-name)
+ epa-file-inhibit-auto-save)
+ (auto-save-mode 0))
+ (set-buffer-modified-p nil))
+
+(defun epa-file-select-keys ()
+ "Select recipients for encryption."
+ (interactive)
+ (make-local-variable 'epa-file-encrypt-to)
+ (setq epa-file-encrypt-to
+ (epa-select-keys
+ (epg-make-context)
+ "Select recipents for encryption.
If no one is selected, symmetric encryption will be performed. ")))
- nil (expand-file-name (buffer-file-name)))
- (set-buffer-modified-p nil)
- t))
+
+;;;###autoload
+(defun epa-file-enable ()
+ (interactive)
+ (if (memq epa-file-handler file-name-handler-alist)
+ (message "`epa-file' already enabled")
+ (setq file-name-handler-alist
+ (cons epa-file-handler file-name-handler-alist))
+ (add-hook 'find-file-hooks 'epa-file-find-file-hook)
+ (message "`epa-file' enabled")))
+
+;;;###autoload
+(defun epa-file-disable ()
+ (interactive)
+ (if (memq epa-file-handler file-name-handler-alist)
+ (progn
+ (setq file-name-handler-alist
+ (delq epa-file-handler file-name-handler-alist))
+ (remove-hook 'find-file-hooks 'epa-file-find-file-hook)
+ (message "`epa-file' disabled"))
+ (message "`epa-file' already disabled")))
(provide 'epa-file)
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