[bpt/emacs.git] / lisp / epa-file.el

;;; epa-file.el --- the EasyPG Assistant, transparent file encryption
;; Copyright (C) 2006, 2007, 2008 Free Software Foundation, Inc.

;; Author: Daiki Ueno <ueno@unixuser.org>
;; Keywords: PGP, GnuPG

;; This file is part of GNU Emacs.

;; GNU Emacs is free software: you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.

;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.

;;; Code:

(require 'epa)
(require 'epa-hook)

(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-select-keys nil
  "If non-nil, always asks user to select recipients."
  :type 'boolean
  :group 'epa-file)

(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-passphrase-callback-function (context key-id file)
  (if (and epa-file-cache-passphrase-for-symmetric-encryption
	   (eq key-id 'SYM))
      (progn
	(setq file (file-truename file))
	(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)))

;;;###autoload
(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
	  (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)
		 (unless start
		   (setq start (point-min))
		   (setq end (point-max)))
		 (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-select-keys ()
  "Select recipients for encryption."
  (interactive)
  (make-local-variable 'epa-file-encrypt-to)
  (setq epa-file-encrypt-to
	(mapcar
	 (lambda (key)
	   (epg-sub-key-id (car (epg-key-sub-key-list key))))
	(epa-select-keys
	 (epg-make-context)
	 "Select recipents for encryption.
If no one is selected, symmetric encryption will be performed.  "))))

;;;###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-hook 'epa-file-find-file-hook)
    (setq auto-mode-alist (cons epa-file-auto-mode-alist-entry auto-mode-alist))
    (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-hook 'epa-file-find-file-hook)
	(setq auto-mode-alist (delq epa-file-auto-mode-alist-entry
				    auto-mode-alist))
	(message "`epa-file' disabled"))
    (message "`epa-file' already disabled")))

(provide 'epa-file)

;; arch-tag: 5715152f-0eb1-4dbc-9008-07098775314d
;;; epa-file.el ends here
Commit	Line	Data
c154c0be MO	1	;;; epa-file.el --- the EasyPG Assistant, transparent file encryption
	2	;; Copyright (C) 2006, 2007, 2008 Free Software Foundation, Inc.
	3
	4	;; Author: Daiki Ueno <ueno@unixuser.org>
	5	;; Keywords: PGP, GnuPG
	6
	7	;; This file is part of GNU Emacs.
	8
eb3fa2cf	9	;; GNU Emacs is free software: you can redistribute it and/or modify
c154c0be	10	;; it under the terms of the GNU General Public License as published by
eb3fa2cf GM	11	;; the Free Software Foundation, either version 3 of the License, or
eb3fa2cf GM	12	;; (at your option) any later version.
c154c0be MO	13
	14	;; GNU Emacs 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.
	18
	19	;; You should have received a copy of the GNU General Public License
eb3fa2cf	20	;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>.
c154c0be MO	21
	22	;;; Code:
	23
	24	(require 'epa)
3fe68728	25	(require 'epa-hook)
c154c0be MO	26
	27	(defcustom epa-file-cache-passphrase-for-symmetric-encryption nil
	28	"If non-nil, cache passphrase for symmetric encryption."
	29	:type 'boolean
	30	:group 'epa-file)
	31
c154c0be MO	32	(defcustom epa-file-select-keys nil
	33	"If non-nil, always asks user to select recipients."
	34	:type 'boolean
	35	:group 'epa-file)
	36
c154c0be MO	37	(defvar epa-file-passphrase-alist nil)
	38
	39	(eval-and-compile
	40	(if (fboundp 'encode-coding-string)
	41	(defalias 'epa-file--encode-coding-string 'encode-coding-string)
	42	(defalias 'epa-file--encode-coding-string 'identity)))
	43
	44	(eval-and-compile
	45	(if (fboundp 'decode-coding-string)
	46	(defalias 'epa-file--decode-coding-string 'decode-coding-string)
	47	(defalias 'epa-file--decode-coding-string 'identity)))
	48
c154c0be MO	49	(defun epa-file-passphrase-callback-function (context key-id file)
	50	(if (and epa-file-cache-passphrase-for-symmetric-encryption
	51	(eq key-id 'SYM))
	52	(progn
	53	(setq file (file-truename file))
	54	(let ((entry (assoc file epa-file-passphrase-alist))
	55	passphrase)
	56	(or (copy-sequence (cdr entry))
	57	(progn
	58	(unless entry
	59	(setq entry (list file)
	60	epa-file-passphrase-alist
	61	(cons entry
	62	epa-file-passphrase-alist)))
	63	(setq passphrase (epa-passphrase-callback-function context
	64	key-id nil))
	65	(setcdr entry (copy-sequence passphrase))
	66	passphrase))))
	67	(epa-passphrase-callback-function context key-id nil)))
	68
6f8a4190	69	;;;###autoload
c154c0be	70	(defun epa-file-handler (operation &rest args)
dbc9f96d GM	71	(save-match-data
	72	(let ((op (get operation 'epa-file)))
	73	(if op
	74	(apply op args)
	75	(epa-file-run-real-handler operation args)))))
	76
c154c0be MO	77	(defun epa-file-run-real-handler (operation args)
	78	(let ((inhibit-file-name-handlers
	79	(cons 'epa-file-handler
	80	(and (eq inhibit-file-name-operation operation)
	81	inhibit-file-name-handlers)))
	82	(inhibit-file-name-operation operation))
	83	(apply operation args)))
	84
	85	(defun epa-file-decode-and-insert (string file visit beg end replace)
	86	(if (fboundp 'decode-coding-inserted-region)
	87	(save-restriction
	88	(narrow-to-region (point) (point))
	89	(let ((multibyte enable-multibyte-characters))
	90	(set-buffer-multibyte nil)
	91	(insert string)
	92	(set-buffer-multibyte multibyte)
	93	(decode-coding-inserted-region
	94	(point-min) (point-max)
	95	(substring file 0 (string-match epa-file-name-regexp file))
	96	visit beg end replace)))
	97	(insert (epa-file--decode-coding-string string (or coding-system-for-read
	98	'undecided)))))
	99
	100	(defvar last-coding-system-used)
	101	(defun epa-file-insert-file-contents (file &optional visit beg end replace)
	102	(barf-if-buffer-read-only)
	103	(if (and visit (or beg end))
	104	(error "Attempt to visit less than an entire file"))
	105	(setq file (expand-file-name file))
	106	(let* ((local-copy
	107	(condition-case inl
	108	(epa-file-run-real-handler #'file-local-copy (list file))
	109	(error)))
	110	(local-file (or local-copy file))
	111	(context (epg-make-context))
	112	string length entry)
	113	(if visit
	114	(setq buffer-file-name file))
	115	(epg-context-set-passphrase-callback
	116	context
	117	(cons #'epa-file-passphrase-callback-function
	118	local-file))
	119	(epg-context-set-progress-callback context
	120	#'epa-progress-callback-function)
	121	(unwind-protect
	122	(progn
	123	(if replace
	124	(goto-char (point-min)))
	125	(condition-case error
	126	(setq string (epg-decrypt-file context local-file nil))
	127	(error
	128	(if (setq entry (assoc file epa-file-passphrase-alist))
	129	(setcdr entry nil))
	130	(signal 'file-error
	131	(cons "Opening input file" (cdr error)))))
	132	(make-local-variable 'epa-file-encrypt-to)
	133	(setq epa-file-encrypt-to
	134	(mapcar #'car (epg-context-result-for context 'encrypted-to)))
	135	(if (or beg end)
	136	(setq string (substring string (or beg 0) end)))
	137	(save-excursion
	138	(save-restriction
	139	(narrow-to-region (point) (point))
	140	(epa-file-decode-and-insert string file visit beg end replace)
141	(setq length (- (point-max) (point-min))))
142	(if replace
143	(delete-region (point) (point-max)))))
144	(if (and local-copy
145	(file-exists-p local-copy))
146	(delete-file local-copy)))
147	(list file length)))
148	(put 'insert-file-contents 'epa-file 'epa-file-insert-file-contents)
149
150	(defun epa-file-write-region (start end file &optional append visit lockname
151	mustbenew)
152	(if append
153	(error "Can't append to the file."))
154	(setq file (expand-file-name file))
155	(let* ((coding-system (or coding-system-for-write
156	(if (fboundp 'select-safe-coding-system)
157	;; This is needed since Emacs 22 has
158	;; no-conversion setting for *.gpg in
159	;; `auto-coding-alist'.
160	(let ((buffer-file-name
161	(file-name-sans-extension file)))
162	(select-safe-coding-system
163	(point-min) (point-max)))
164	buffer-file-coding-system)))
165	(context (epg-make-context))
166	(coding-system-for-write 'binary)
167	string entry
168	(recipients
169	(cond
170	((listp epa-file-encrypt-to) epa-file-encrypt-to)
171	((stringp epa-file-encrypt-to) (list epa-file-encrypt-to)))))
172	(epg-context-set-passphrase-callback
173	context
174	(cons #'epa-file-passphrase-callback-function
175	file))
176	(epg-context-set-progress-callback context
177	#'epa-progress-callback-function)
178	(epg-context-set-armor context epa-armor)
179	(condition-case error
180	(setq string
181	(epg-encrypt-string
182	context
183	(if (stringp start)
184	(epa-file--encode-coding-string start coding-system)
6843296d DU	185	(unless start
	186	(setq start (point-min))
	187	(setq end (point-max)))
c154c0be MO	188	(epa-file--encode-coding-string (buffer-substring start end)
	189	coding-system))
	190	(if (or epa-file-select-keys
	191	(not (local-variable-p 'epa-file-encrypt-to
	192	(current-buffer))))
	193	(epa-select-keys
	194	context
	195	"Select recipents for encryption.
	196	If no one is selected, symmetric encryption will be performed. "
	197	recipients)
	198	(if epa-file-encrypt-to
	199	(epg-list-keys context recipients)))))
	200	(error
	201	(if (setq entry (assoc file epa-file-passphrase-alist))
	202	(setcdr entry nil))
	203	(signal 'file-error (cons "Opening output file" (cdr error)))))
	204	(epa-file-run-real-handler
	205	#'write-region
	206	(list string nil file append visit lockname mustbenew))
	207	(if (boundp 'last-coding-system-used)
	208	(setq last-coding-system-used coding-system))
	209	(if (eq visit t)
	210	(progn
	211	(setq buffer-file-name file)
	212	(set-visited-file-modtime))
	213	(if (stringp visit)
	214	(progn
	215	(set-visited-file-modtime)
	216	(setq buffer-file-name visit))))
	217	(if (or (eq visit t)
	218	(eq visit nil)
	219	(stringp visit))
	220	(message "Wrote %s" buffer-file-name))))
	221	(put 'write-region 'epa-file 'epa-file-write-region)
	222
c154c0be MO	223	(defun epa-file-select-keys ()
	224	"Select recipients for encryption."
	225	(interactive)
	226	(make-local-variable 'epa-file-encrypt-to)
	227	(setq epa-file-encrypt-to
fef7aa9e MO	228	(mapcar
	229	(lambda (key)
	230	(epg-sub-key-id (car (epg-key-sub-key-list key))))
c154c0be MO	231	(epa-select-keys
	232	(epg-make-context)
	233	"Select recipents for encryption.
fef7aa9e	234	If no one is selected, symmetric encryption will be performed. "))))
c154c0be MO	235
	236	;;;###autoload
	237	(defun epa-file-enable ()
	238	(interactive)
	239	(if (memq epa-file-handler file-name-handler-alist)
	240	(message "`epa-file' already enabled")
	241	(setq file-name-handler-alist
	242	(cons epa-file-handler file-name-handler-alist))
bfeee9d1	243	(add-hook 'find-file-hook 'epa-file-find-file-hook)
c154c0be MO	244	(setq auto-mode-alist (cons epa-file-auto-mode-alist-entry auto-mode-alist))
	245	(message "`epa-file' enabled")))
	246
	247	;;;###autoload
	248	(defun epa-file-disable ()
	249	(interactive)
	250	(if (memq epa-file-handler file-name-handler-alist)
	251	(progn
	252	(setq file-name-handler-alist
	253	(delq epa-file-handler file-name-handler-alist))
bfeee9d1	254	(remove-hook 'find-file-hook 'epa-file-find-file-hook)
c154c0be MO	255	(setq auto-mode-alist (delq epa-file-auto-mode-alist-entry
	256	auto-mode-alist))
	257	(message "`epa-file' disabled"))
	258	(message "`epa-file' already disabled")))
	259
	260	(provide 'epa-file)
	261
37b77401	262	;; arch-tag: 5715152f-0eb1-4dbc-9008-07098775314d
c154c0be	263	;;; epa-file.el ends here