lisp/epg-config.el

   1 ;;; epg-config.el --- configuration of the EasyPG Library
   2
   3 ;; Copyright (C) 2006-2011 Free Software Foundation, Inc.
   4
   5 ;; Author: Daiki Ueno <ueno@unixuser.org>
   6 ;; Keywords: PGP, GnuPG
   7 ;; Package: epg
   8
   9 ;; This file is part of GNU Emacs.
  10
  11 ;; GNU Emacs is free software: you can redistribute it and/or modify
  12 ;; it under the terms of the GNU General Public License as published by
  13 ;; the Free Software Foundation, either version 3 of the License, or
  14 ;; (at your option) any later version.
  15
  16 ;; GNU Emacs is distributed in the hope that it will be useful,
  17 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 ;; GNU General Public License for more details.
  20
  21 ;; You should have received a copy of the GNU General Public License
  22 ;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
  23
  24 ;;; Code:
  25
  26 (defconst epg-package-name "epg"
  27   "Name of this package.")
  28
  29 (defconst epg-version-number "1.0.0"
  30   "Version number of this package.")
  31
  32 (defconst epg-bug-report-address "ueno@unixuser.org"
  33   "Report bugs to this address.")
  34
  35 (defgroup epg ()
  36   "The EasyPG library."
  37   :version "23.1"
  38   :group 'data)
  39
  40 (defcustom epg-gpg-program (or (executable-find "gpg")
  41                                (executable-find "gpg2")
  42                                "gpg")
  43   "The `gpg' executable."
  44   :group 'epg
  45   :type 'string)
  46
  47 (defcustom epg-gpgsm-program "gpgsm"
  48   "The `gpgsm' executable."
  49   :group 'epg
  50   :type 'string)
  51
  52 (defcustom epg-gpg-home-directory nil
  53   "The directory which contains the configuration files of `epg-gpg-program'."
  54   :group 'epg
  55   :type '(choice (const :tag "Default" nil) directory))
  56
  57 (defcustom epg-passphrase-coding-system nil
  58   "Coding system to use with messages from `epg-gpg-program'."
  59   :group 'epg
  60   :type 'symbol)
  61
  62 (defcustom epg-debug nil
  63   "If non-nil, debug output goes to the \" *epg-debug*\" buffer.
  64 Note that the buffer name starts with a space."
  65   :group 'epg
  66   :type 'boolean)
  67
  68 (defconst epg-gpg-minimum-version "1.4.3")
  69
  70 ;;;###autoload
  71 (defun epg-configuration ()
  72   "Return a list of internal configuration parameters of `epg-gpg-program'."
  73   (let (config groups type args)
  74     (with-temp-buffer
  75       (apply #'call-process epg-gpg-program nil (list t nil) nil
  76              (append (if epg-gpg-home-directory
  77                          (list "--homedir" epg-gpg-home-directory))
  78                      '("--with-colons" "--list-config")))
  79       (goto-char (point-min))
  80       (while (re-search-forward "^cfg:\\([^:]+\\):\\(.*\\)" nil t)
  81         (setq type (intern (match-string 1))
  82               args (match-string 2))
  83         (cond
  84          ((eq type 'group)
  85           (if (string-match "\\`\\([^:]+\\):" args)
  86                   (setq groups
  87                         (cons (cons (downcase (match-string 1 args))
  88                                     (delete "" (split-string
  89                                                 (substring args
  90                                                            (match-end 0))
  91                                                 ";")))
  92                               groups))
  93             (if epg-debug
  94                 (message "Invalid group configuration: %S" args))))
  95          ((memq type '(pubkey cipher digest compress))
  96           (if (string-match "\\`\\([0-9]+\\)\\(;[0-9]+\\)*" args)
  97               (setq config
  98                     (cons (cons type
  99                                 (mapcar #'string-to-number
 100                                         (delete "" (split-string args ";"))))
 101                           config))
 102             (if epg-debug
 103                 (message "Invalid %S algorithm configuration: %S"
 104                          type args))))
 105          (t
 106           (setq config (cons (cons type args) config))))))
 107     (if groups
 108         (cons (cons 'groups groups) config)
 109       config)))
 110
 111 (defun epg-config--parse-version (string)
 112   (let ((index 0)
 113         version)
 114     (while (eq index (string-match "\\([0-9]+\\)\\.?" string index))
 115       (setq version (cons (string-to-number (match-string 1 string))
 116                           version)
 117             index (match-end 0)))
 118     (nreverse version)))
 119
 120 (defun epg-config--compare-version (v1 v2)
 121   (while (and v1 v2 (= (car v1) (car v2)))
 122     (setq v1 (cdr v1) v2 (cdr v2)))
 123   (- (or (car v1) 0) (or (car v2) 0)))
 124
 125 ;;;###autoload
 126 (defun epg-check-configuration (config &optional minimum-version)
 127   "Verify that a sufficient version of GnuPG is installed."
 128   (let ((entry (assq 'version config))
 129         version)
 130     (unless (and entry
 131                  (stringp (cdr entry)))
 132       (error "Undetermined version: %S" entry))
 133     (setq version (epg-config--parse-version (cdr entry))
 134           minimum-version (epg-config--parse-version
 135                            (or minimum-version
 136                                epg-gpg-minimum-version)))
 137     (unless (>= (epg-config--compare-version version minimum-version) 0)
 138       (error "Unsupported version: %s" (cdr entry)))))
 139
 140 ;;;###autoload
 141 (defun epg-expand-group (config group)
 142   "Look at CONFIG and try to expand GROUP."
 143   (let ((entry (assq 'groups config)))
 144     (if (and entry
 145              (setq entry (assoc (downcase group) (cdr entry))))
 146         (cdr entry))))
 147
 148 (provide 'epg-config)
 149
 150 ;;; epg-config.el ends here