1 ;;; epa-file.el --- the EasyPG Assistant, transparent file encryption
2 ;; Copyright (C) 2006 Daiki Ueno
4 ;; Author: Daiki Ueno <ueno@unixuser.org>
5 ;; Keywords: PGP, GnuPG
7 ;; This file is part of EasyPG.
9 ;; This program is free software; you can redistribute it and/or modify
10 ;; it under the terms of the GNU General Public License as published by
11 ;; the Free Software Foundation; either version 2, or (at your option)
14 ;; This program is distributed in the hope that it will be useful,
15 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
16 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 ;; GNU General Public License for more details.
19 ;; You should have received a copy of the GNU General Public License
20 ;; along with GNU Emacs; see the file COPYING. If not, write to the
21 ;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
22 ;; Boston, MA 02110-1301, USA.
28 (defgroup epa-file nil
29 "The EasyPG Assistant hooks for transparent file encryption"
32 (defun epa-file--file-name-regexp-set (variable value)
33 (set-default variable value)
34 (if (fboundp 'epa-file-name-regexp-update)
35 (epa-file-name-regexp-update)))
37 (defcustom epa-file-name-regexp "\\.gpg\\(~\\|\\.~[0-9]+~\\)?\\'"
38 "Regexp which matches filenames to be encrypted with GnuPG.
40 If you set this outside Custom while epa-file is already enabled, you
41 have to call `epa-file-name-regexp-update' after setting it to
42 properly update file-name-handler-alist. Setting this through Custom
43 does that automatically."
46 :set 'epa-file--file-name-regexp-set)
48 (defcustom epa-file-cache-passphrase-for-symmetric-encryption nil
49 "If non-nil, cache passphrase for symmetric encryption."
53 (defcustom epa-file-inhibit-auto-save t
54 "If non-nil, disable auto-saving when opening an encrypted file."
58 (defcustom epa-file-select-keys nil
59 "If non-nil, always asks user to select recipients."
63 (defvar epa-file-encrypt-to nil
64 "*Recipient(s) used for encrypting files.
65 May either be a string or a list of strings.")
68 (put 'epa-file-encrypt-to 'safe-local-variable
80 (put 'epa-file-encrypt-to 'permanent-local t)
82 (defvar epa-file-handler
83 (cons epa-file-name-regexp 'epa-file-handler))
85 (defvar epa-file-auto-mode-alist-entry
86 (list epa-file-name-regexp nil 'epa-file))
88 (defvar epa-file-passphrase-alist nil)
91 (if (fboundp 'encode-coding-string)
92 (defalias 'epa-file--encode-coding-string 'encode-coding-string)
93 (defalias 'epa-file--encode-coding-string 'identity)))
96 (if (fboundp 'decode-coding-string)
97 (defalias 'epa-file--decode-coding-string 'decode-coding-string)
98 (defalias 'epa-file--decode-coding-string 'identity)))
100 (defun epa-file-name-regexp-update ()
102 (unless (equal (car epa-file-handler) epa-file-name-regexp)
103 (setcar epa-file-handler epa-file-name-regexp)))
105 (defun epa-file-passphrase-callback-function (context key-id file)
106 (if (and epa-file-cache-passphrase-for-symmetric-encryption
108 (let ((entry (assoc file epa-file-passphrase-alist))
110 (or (copy-sequence (cdr entry))
113 (setq entry (list file)
114 epa-file-passphrase-alist (cons entry
115 epa-file-passphrase-alist)))
116 (setq passphrase (epa-passphrase-callback-function context
118 (setcdr entry (copy-sequence passphrase))
120 (epa-passphrase-callback-function context key-id nil)))
122 (defun epa-file-handler (operation &rest args)
124 (let ((op (get operation 'epa-file)))
127 (epa-file-run-real-handler operation args)))))
129 (defun epa-file-run-real-handler (operation args)
130 (let ((inhibit-file-name-handlers
131 (cons 'epa-file-handler
132 (and (eq inhibit-file-name-operation operation)
133 inhibit-file-name-handlers)))
134 (inhibit-file-name-operation operation))
135 (apply operation args)))
137 (defun epa-file-decode-and-insert (string file visit beg end replace)
138 (if (fboundp 'decode-coding-inserted-region)
140 (narrow-to-region (point) (point))
141 (let ((multibyte enable-multibyte-characters))
142 (set-buffer-multibyte nil)
144 (set-buffer-multibyte multibyte)
145 (decode-coding-inserted-region
146 (point-min) (point-max)
147 (substring file 0 (string-match epa-file-name-regexp file))
148 visit beg end replace)))
149 (insert (epa-file--decode-coding-string string (or coding-system-for-read
152 (defvar last-coding-system-used)
153 (defun epa-file-insert-file-contents (file &optional visit beg end replace)
154 (barf-if-buffer-read-only)
155 (if (and visit (or beg end))
156 (error "Attempt to visit less than an entire file"))
157 (setq file (expand-file-name file))
160 (epa-file-run-real-handler #'file-local-copy (list file))
162 (local-file (or local-copy file))
163 (context (epg-make-context))
166 (setq buffer-file-name file))
167 (epg-context-set-passphrase-callback
169 (cons #'epa-file-passphrase-callback-function
171 (epg-context-set-progress-callback context
172 #'epa-progress-callback-function)
176 (goto-char (point-min)))
177 (condition-case error
178 (setq string (epg-decrypt-file context local-file nil))
180 (if (setq entry (assoc file epa-file-passphrase-alist))
183 (cons "Opening input file" (cdr error)))))
184 (make-local-variable 'epa-file-encrypt-to)
185 (setq epa-file-encrypt-to
186 (mapcar #'car (epg-context-result-for context 'encrypted-to)))
188 (setq string (substring string (or beg 0) end)))
191 (narrow-to-region (point) (point))
192 (epa-file-decode-and-insert string file visit beg end replace)
193 (setq length (- (point-max) (point-min))))
195 (delete-region (point) (point-max)))))
197 (file-exists-p local-copy))
198 (delete-file local-copy)))
200 (put 'insert-file-contents 'epa-file 'epa-file-insert-file-contents)
202 (defun epa-file-write-region (start end file &optional append visit lockname
205 (error "Can't append to the file."))
206 (setq file (expand-file-name file))
207 (let* ((coding-system (or coding-system-for-write
208 (if (fboundp 'select-safe-coding-system)
209 ;; This is needed since Emacs 22 has
210 ;; no-conversion setting for *.gpg in
211 ;; `auto-coding-alist'.
212 (let ((buffer-file-name
213 (file-name-sans-extension file)))
214 (select-safe-coding-system
215 (point-min) (point-max)))
216 buffer-file-coding-system)))
217 (context (epg-make-context))
218 (coding-system-for-write 'binary)
222 ((listp epa-file-encrypt-to) epa-file-encrypt-to)
223 ((stringp epa-file-encrypt-to) (list epa-file-encrypt-to)))))
224 (epg-context-set-passphrase-callback
226 (cons #'epa-file-passphrase-callback-function
228 (epg-context-set-progress-callback context
229 #'epa-progress-callback-function)
230 (epg-context-set-armor context epa-armor)
231 (condition-case error
236 (epa-file--encode-coding-string start coding-system)
237 (epa-file--encode-coding-string (buffer-substring start end)
239 (if (or epa-file-select-keys
240 (not (local-variable-p 'epa-file-encrypt-to
244 "Select recipents for encryption.
245 If no one is selected, symmetric encryption will be performed. "
247 (if epa-file-encrypt-to
248 (epg-list-keys context recipients)))))
250 (if (setq entry (assoc file epa-file-passphrase-alist))
252 (signal 'file-error (cons "Opening output file" (cdr error)))))
253 (epa-file-run-real-handler
255 (list string nil file append visit lockname mustbenew))
256 (if (boundp 'last-coding-system-used)
257 (setq last-coding-system-used coding-system))
260 (setq buffer-file-name file)
261 (set-visited-file-modtime))
264 (set-visited-file-modtime)
265 (setq buffer-file-name visit))))
269 (message "Wrote %s" buffer-file-name))))
270 (put 'write-region 'epa-file 'epa-file-write-region)
272 (defun epa-file-find-file-hook ()
273 (if (and buffer-file-name
274 (string-match epa-file-name-regexp buffer-file-name)
275 epa-file-inhibit-auto-save)
277 (set-buffer-modified-p nil))
279 (defun epa-file-select-keys ()
280 "Select recipients for encryption."
282 (make-local-variable 'epa-file-encrypt-to)
283 (setq epa-file-encrypt-to
286 "Select recipents for encryption.
287 If no one is selected, symmetric encryption will be performed. ")))
290 (defun epa-file-enable ()
292 (if (memq epa-file-handler file-name-handler-alist)
293 (message "`epa-file' already enabled")
294 (setq file-name-handler-alist
295 (cons epa-file-handler file-name-handler-alist))
296 (add-hook 'find-file-hooks 'epa-file-find-file-hook)
297 (setq auto-mode-alist (cons epa-file-auto-mode-alist-entry auto-mode-alist))
298 (message "`epa-file' enabled")))
301 (defun epa-file-disable ()
303 (if (memq epa-file-handler file-name-handler-alist)
305 (setq file-name-handler-alist
306 (delq epa-file-handler file-name-handler-alist))
307 (remove-hook 'find-file-hooks 'epa-file-find-file-hook)
308 (setq auto-mode-alist (delq epa-file-auto-mode-alist-entry
310 (message "`epa-file' disabled"))
311 (message "`epa-file' already disabled")))
315 ;;; epa-file.el ends here