1 ;;; epa-file.el --- the EasyPG Assistant, transparent file encryption
2 ;; Copyright (C) 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
4 ;; Author: Daiki Ueno <ueno@unixuser.org>
5 ;; Keywords: PGP, GnuPG
8 ;; This file is part of GNU Emacs.
10 ;; GNU Emacs is free software: you can redistribute it and/or modify
11 ;; it under the terms of the GNU General Public License as published by
12 ;; the Free Software Foundation, either version 3 of the License, or
13 ;; (at your option) any later version.
15 ;; GNU Emacs is distributed in the hope that it will be useful,
16 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
17 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 ;; GNU General Public License for more details.
20 ;; You should have received a copy of the GNU General Public License
21 ;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>.
28 (defcustom epa-file-cache-passphrase-for-symmetric-encryption nil
29 "If non-nil, cache passphrase for symmetric encryption.
31 For security reasons, this option is turned off by default and
32 not recommended to use. Instead, consider using public-key
33 encryption with gpg-agent which does the same job in a safer
38 (defcustom epa-file-select-keys nil
39 "If non-nil, always asks user to select recipients."
43 (defvar epa-file-passphrase-alist nil
)
46 (if (fboundp 'encode-coding-string
)
47 (defalias 'epa-file--encode-coding-string
'encode-coding-string
)
48 (defalias 'epa-file--encode-coding-string
'identity
)))
51 (if (fboundp 'decode-coding-string
)
52 (defalias 'epa-file--decode-coding-string
'decode-coding-string
)
53 (defalias 'epa-file--decode-coding-string
'identity
)))
55 (defun epa-file-passphrase-callback-function (context key-id file
)
56 (if (and epa-file-cache-passphrase-for-symmetric-encryption
59 (setq file
(file-truename file
))
60 (let ((entry (assoc file epa-file-passphrase-alist
))
62 (or (copy-sequence (cdr entry
))
65 (setq entry
(list file
)
66 epa-file-passphrase-alist
68 epa-file-passphrase-alist
)))
69 (setq passphrase
(epa-passphrase-callback-function context
71 (setcdr entry
(copy-sequence passphrase
))
73 (epa-passphrase-callback-function context key-id nil
)))
76 (defun epa-file-handler (operation &rest args
)
78 (let ((op (get operation
'epa-file
)))
81 (epa-file-run-real-handler operation args
)))))
83 (defun epa-file-run-real-handler (operation args
)
84 (let ((inhibit-file-name-handlers
85 (cons 'epa-file-handler
86 (and (eq inhibit-file-name-operation operation
)
87 inhibit-file-name-handlers
)))
88 (inhibit-file-name-operation operation
))
89 (apply operation args
)))
91 (defun epa-file-decode-and-insert (string file visit beg end replace
)
92 (if (fboundp 'decode-coding-inserted-region
)
94 (narrow-to-region (point) (point))
95 (insert (if enable-multibyte-characters
96 (string-to-multibyte string
)
98 (decode-coding-inserted-region
99 (point-min) (point-max)
100 (substring file
0 (string-match epa-file-name-regexp file
))
101 visit beg end replace
))
102 (insert (epa-file--decode-coding-string string
(or coding-system-for-read
105 (defvar epa-file-error nil
)
106 (defun epa-file--find-file-not-found-function ()
107 (let ((error epa-file-error
))
108 (save-window-excursion
111 (cons "Opening input file" (cdr error
)))))
113 (defvar last-coding-system-used
)
114 (defun epa-file-insert-file-contents (file &optional visit beg end replace
)
115 (barf-if-buffer-read-only)
116 (if (and visit
(or beg end
))
117 (error "Attempt to visit less than an entire file"))
118 (setq file
(expand-file-name file
))
121 (epa-file-run-real-handler #'file-local-copy
(list file
))
123 (local-file (or local-copy file
))
124 (context (epg-make-context))
127 (setq buffer-file-name file
))
128 (epg-context-set-passphrase-callback
130 (cons #'epa-file-passphrase-callback-function
132 (epg-context-set-progress-callback context
133 #'epa-progress-callback-function
)
137 (goto-char (point-min)))
138 (condition-case error
139 (setq string
(epg-decrypt-file context local-file nil
))
141 (if (setq entry
(assoc file epa-file-passphrase-alist
))
143 ;; Hack to prevent find-file from opening empty buffer
144 ;; when decryption failed (bug#6568). See the place
145 ;; where `find-file-not-found-functions' are called in
146 ;; `find-file-noselect-1'.
147 (when (file-exists-p local-file
)
148 (make-local-variable 'epa-file-error
)
149 (setq epa-file-error error
)
150 (add-hook 'find-file-not-found-functions
151 'epa-file--find-file-not-found-function
154 (cons "Opening input file" (cdr error
)))))
155 (make-local-variable 'epa-file-encrypt-to
)
156 (setq epa-file-encrypt-to
157 (mapcar #'car
(epg-context-result-for context
'encrypted-to
)))
159 (setq string
(substring string
(or beg
0) end
)))
162 (narrow-to-region (point) (point))
163 (epa-file-decode-and-insert string file visit beg end replace
)
164 (setq length
(- (point-max) (point-min))))
166 (delete-region (point) (point-max)))
168 (set-visited-file-modtime))))
170 (file-exists-p local-copy
))
171 (delete-file local-copy
)))
173 (put 'insert-file-contents
'epa-file
'epa-file-insert-file-contents
)
175 (defun epa-file-write-region (start end file
&optional append visit lockname
178 (error "Can't append to the file"))
179 (setq file
(expand-file-name file
))
180 (let* ((coding-system (or coding-system-for-write
181 (if (fboundp 'select-safe-coding-system
)
182 ;; This is needed since Emacs 22 has
183 ;; no-conversion setting for *.gpg in
184 ;; `auto-coding-alist'.
185 (let ((buffer-file-name
186 (file-name-sans-extension file
)))
187 (select-safe-coding-system
188 (point-min) (point-max)))
189 buffer-file-coding-system
)))
190 (context (epg-make-context))
191 (coding-system-for-write 'binary
)
195 ((listp epa-file-encrypt-to
) epa-file-encrypt-to
)
196 ((stringp epa-file-encrypt-to
) (list epa-file-encrypt-to
)))))
197 (epg-context-set-passphrase-callback
199 (cons #'epa-file-passphrase-callback-function
201 (epg-context-set-progress-callback context
202 #'epa-progress-callback-function
)
203 (epg-context-set-armor context epa-armor
)
204 (condition-case error
209 (epa-file--encode-coding-string start coding-system
)
211 (setq start
(point-min)
213 (epa-file--encode-coding-string (buffer-substring start end
)
215 (if (or epa-file-select-keys
216 (not (local-variable-p 'epa-file-encrypt-to
220 "Select recipents for encryption.
221 If no one is selected, symmetric encryption will be performed. "
223 (if epa-file-encrypt-to
224 (epg-list-keys context recipients
)))))
226 (if (setq entry
(assoc file epa-file-passphrase-alist
))
228 (signal 'file-error
(cons "Opening output file" (cdr error
)))))
229 (epa-file-run-real-handler
231 (list string nil file append visit lockname mustbenew
))
232 (if (boundp 'last-coding-system-used
)
233 (setq last-coding-system-used coding-system
))
236 (setq buffer-file-name file
)
237 (set-visited-file-modtime))
240 (set-visited-file-modtime)
241 (setq buffer-file-name visit
))))
245 (message "Wrote %s" buffer-file-name
))))
246 (put 'write-region
'epa-file
'epa-file-write-region
)
248 (defun epa-file-select-keys ()
249 "Select recipients for encryption."
251 (make-local-variable 'epa-file-encrypt-to
)
252 (setq epa-file-encrypt-to
255 (epg-sub-key-id (car (epg-key-sub-key-list key
))))
258 "Select recipents for encryption.
259 If no one is selected, symmetric encryption will be performed. "))))
262 (defun epa-file-enable ()
264 (if (memq epa-file-handler file-name-handler-alist
)
265 (message "`epa-file' already enabled")
266 (setq file-name-handler-alist
267 (cons epa-file-handler file-name-handler-alist
))
268 (add-hook 'find-file-hook
'epa-file-find-file-hook
)
269 (setq auto-mode-alist
(cons epa-file-auto-mode-alist-entry auto-mode-alist
))
270 (message "`epa-file' enabled")))
273 (defun epa-file-disable ()
275 (if (memq epa-file-handler file-name-handler-alist
)
277 (setq file-name-handler-alist
278 (delq epa-file-handler file-name-handler-alist
))
279 (remove-hook 'find-file-hook
'epa-file-find-file-hook
)
280 (setq auto-mode-alist
(delq epa-file-auto-mode-alist-entry
282 (message "`epa-file' disabled"))
283 (message "`epa-file' already disabled")))
287 ;; arch-tag: 5715152f-0eb1-4dbc-9008-07098775314d
288 ;;; epa-file.el ends here