lisp/epg-config.el

   1 ;;; epg-config.el --- configuration of the EasyPG Library
   2
   3 ;; Copyright (C) 2006-2013 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   "Interface to the GNU Privacy Guard (GnuPG)."
  37   :tag "EasyPG"
  38   :version "23.1"
  39   :group 'data
  40   :group 'external)
  41
  42 (defcustom epg-gpg-program (or (executable-find "gpg")
  43                                (executable-find "gpg2")
  44                                "gpg")
  45   "The `gpg' executable."
  46   :group 'epg
  47   :type 'string)
  48
  49 (defcustom epg-gpgsm-program "gpgsm"
  50   "The `gpgsm' executable."
  51   :group 'epg
  52   :type 'string)
  53
  54 (defcustom epg-gpg-home-directory nil
  55   "The directory which contains the configuration files of `epg-gpg-program'."
  56   :group 'epg
  57   :type '(choice (const :tag "Default" nil) directory))
  58
  59 (defcustom epg-passphrase-coding-system nil
  60   "Coding system to use with messages from `epg-gpg-program'."
  61   :group 'epg
  62   :type 'symbol)
  63
  64 (defcustom epg-debug nil
  65   "If non-nil, debug output goes to the \" *epg-debug*\" buffer.
  66 Note that the buffer name starts with a space."
  67   :group 'epg
  68   :type 'boolean)
  69
  70 (defconst epg-gpg-minimum-version "1.4.3")
  71
  72 ;;;###autoload
  73 (defun epg-configuration ()
  74   "Return a list of internal configuration parameters of `epg-gpg-program'."
  75   (let (config groups type args)
  76     (with-temp-buffer
  77       (apply #'call-process epg-gpg-program nil (list t nil) nil
  78              (append (if epg-gpg-home-directory
  79                          (list "--homedir" epg-gpg-home-directory))
  80                      '("--with-colons" "--list-config")))
  81       (goto-char (point-min))
  82       (while (re-search-forward "^cfg:\\([^:]+\\):\\(.*\\)" nil t)
  83         (setq type (intern (match-string 1))
  84               args (match-string 2))
  85         (cond
  86          ((eq type 'group)
  87           (if (string-match "\\`\\([^:]+\\):" args)
  88                   (setq groups
  89                         (cons (cons (downcase (match-string 1 args))
  90                                     (delete "" (split-string
  91                                                 (substring args
  92                                                            (match-end 0))
  93                                                 ";")))
  94                               groups))
  95             (if epg-debug
  96                 (message "Invalid group configuration: %S" args))))
  97          ((memq type '(pubkey cipher digest compress))
  98           (if (string-match "\\`\\([0-9]+\\)\\(;[0-9]+\\)*" args)
  99               (setq config
 100                     (cons (cons type
 101                                 (mapcar #'string-to-number
 102                                         (delete "" (split-string args ";"))))
 103                           config))
 104             (if epg-debug
 105                 (message "Invalid %S algorithm configuration: %S"
 106                          type args))))
 107          (t
 108           (setq config (cons (cons type args) config))))))
 109     (if groups
 110         (cons (cons 'groups groups) config)
 111       config)))
 112
 113 (defun epg-config--parse-version (string)
 114   (let ((index 0)
 115         version)
 116     (while (eq index (string-match "\\([0-9]+\\)\\.?" string index))
 117       (setq version (cons (string-to-number (match-string 1 string))
 118                           version)
 119             index (match-end 0)))
 120     (nreverse version)))
 121
 122 (defun epg-config--compare-version (v1 v2)
 123   (while (and v1 v2 (= (car v1) (car v2)))
 124     (setq v1 (cdr v1) v2 (cdr v2)))
 125   (- (or (car v1) 0) (or (car v2) 0)))
 126
 127 ;;;###autoload
 128 (defun epg-check-configuration (config &optional minimum-version)
 129   "Verify that a sufficient version of GnuPG is installed."
 130   (let ((entry (assq 'version config))
 131         version)
 132     (unless (and entry
 133                  (stringp (cdr entry)))
 134       (error "Undetermined version: %S" entry))
 135     (setq version (epg-config--parse-version (cdr entry))
 136           minimum-version (epg-config--parse-version
 137                            (or minimum-version
 138                                epg-gpg-minimum-version)))
 139     (unless (>= (epg-config--compare-version version minimum-version) 0)
 140       (error "Unsupported version: %s" (cdr entry)))))
 141
 142 ;;;###autoload
 143 (defun epg-expand-group (config group)
 144   "Look at CONFIG and try to expand GROUP."
 145   (let ((entry (assq 'groups config)))
 146     (if (and entry
 147              (setq entry (assoc (downcase group) (cdr entry))))
 148         (cdr entry))))
 149
 150 (provide 'epg-config)
 151
 152 ;;; epg-config.el ends here