LCOV - code coverage report
Current view: top level - lisp - password-cache.el (source / functions) Hit Total Coverage
Test: tramp-tests.info Lines: 5 24 20.8 %
Date: 2017-08-27 09:44:50 Functions: 2 7 28.6 %

          Line data    Source code
       1             : ;;; password-cache.el --- Read passwords, possibly using a password cache.
       2             : 
       3             : ;; Copyright (C) 1999-2000, 2003-2017 Free Software Foundation, Inc.
       4             : 
       5             : ;; Author: Simon Josefsson <simon@josefsson.org>
       6             : ;; Created: 2003-12-21
       7             : ;; Keywords: password cache passphrase key
       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             : ;;; Commentary:
      25             : 
      26             : ;; Greatly influenced by pgg.el written by Daiki Ueno, with timer
      27             : ;; fixes for XEmacs by Katsumi Yamaoka.  In fact, this is mostly just
      28             : ;; a rip-off.
      29             : ;;
      30             : ;; (password-read "Password? " "test")
      31             : ;; ;; Minibuffer prompt for password.
      32             : ;;  => "foo"
      33             : ;;
      34             : ;; (password-cache-add "test" "foo")
      35             : ;;  => nil
      36             : 
      37             : ;; (password-read "Password? " "test")
      38             : ;; ;; No minibuffer prompt
      39             : ;;  => "foo"
      40             : ;;
      41             : ;; (password-read "Password? " "test")
      42             : ;; ;; No minibuffer prompt
      43             : ;;  => "foo"
      44             : ;;
      45             : ;; ;; Wait `password-cache-expiry' seconds.
      46             : ;;
      47             : ;; (password-read "Password? " "test")
      48             : ;; ;; Minibuffer prompt for password is back.
      49             : ;;  => "foo"
      50             : 
      51             : ;;; Code:
      52             : 
      53             : ;; Options are autoloaded since they are used by eg mml-sec.el.
      54             : 
      55             : ;;;###autoload
      56             : (defcustom password-cache t
      57             :   "Whether to cache passwords."
      58             :   :group 'password
      59             :   :type 'boolean)
      60             : 
      61             : ;;;###autoload
      62             : (defcustom password-cache-expiry 16
      63             :   "How many seconds passwords are cached, or nil to disable expiring.
      64             : Whether passwords are cached at all is controlled by `password-cache'."
      65             :   :group 'password
      66             :   :type '(choice (const :tag "Never" nil)
      67             :                  (integer :tag "Seconds")))
      68             : 
      69             : (defvar password-data (make-hash-table :test #'equal))
      70             : 
      71             : (defun password-read-from-cache (key)
      72             :   "Obtain passphrase for KEY from time-limited passphrase cache.
      73             : Custom variables `password-cache' and `password-cache-expiry'
      74             : regulate cache behavior."
      75           0 :   (and password-cache
      76           0 :        key
      77           0 :        (gethash key password-data)))
      78             : 
      79             : ;;;###autoload
      80             : (defun password-in-cache-p (key)
      81             :   "Check if KEY is in the cache."
      82           0 :   (and password-cache
      83           0 :        key
      84           0 :        (gethash key password-data)))
      85             : 
      86             : (defun password-read (prompt &optional key)
      87             :   "Read password, for use with KEY, from user, or from cache if wanted.
      88             : KEY indicate the purpose of the password, so the cache can
      89             : separate passwords.  The cache is not used if KEY is nil.
      90             : KEY is typically a string but can be anything (compared via `equal').
      91             : The variable `password-cache' control whether the cache is used."
      92           0 :   (or (password-read-from-cache key)
      93           0 :       (read-passwd prompt)))
      94             : 
      95             : (defun password-read-and-add (prompt &optional key)
      96             :   "Read password, for use with KEY, from user, or from cache if wanted.
      97             : Then store the password in the cache.  Uses `password-read' and
      98             : `password-cache-add'.  Custom variables `password-cache' and
      99             : `password-cache-expiry' regulate cache behavior.
     100             : 
     101             : Warning: the password is cached without checking that it is
     102             : correct.  It is better to check the password before caching.  If
     103             : you must use this function, take care to check passwords and
     104             : remove incorrect ones from the cache."
     105             :   (declare (obsolete password-read "23.1"))
     106           0 :   (let ((password (password-read prompt key)))
     107           0 :     (when (and password key)
     108           0 :       (password-cache-add key password))
     109           0 :     password))
     110             : 
     111             : (defun password-cache-remove (key)
     112             :   "Remove password indexed by KEY from password cache.
     113             : This is typically run by a timer setup from `password-cache-add',
     114             : but can be invoked at any time to forcefully remove passwords
     115             : from the cache.  This may be useful when it has been detected
     116             : that a password is invalid, so that `password-read' query the
     117             : user again."
     118           4 :   (let ((password (gethash key password-data)))
     119           4 :     (when (stringp password)
     120           0 :       (if (fboundp 'clear-string)
     121           0 :           (clear-string password)
     122           4 :         (fillarray password ?_)))
     123           4 :     (remhash key password-data)))
     124             : 
     125             : (defun password-cache-add (key password)
     126             :   "Add password to cache.
     127             : The password is removed by a timer after `password-cache-expiry' seconds."
     128           0 :   (when (and password-cache-expiry (null (gethash key password-data)))
     129           0 :     (run-at-time password-cache-expiry nil
     130           0 :                  #'password-cache-remove
     131           0 :                  key))
     132           0 :   (puthash key password password-data)
     133             :   nil)
     134             : 
     135             : (defun password-reset ()
     136             :   "Clear the password cache."
     137             :   (interactive)
     138          11 :   (clrhash password-data))
     139             : 
     140             : (provide 'password-cache)
     141             : 
     142             : ;;; password-cache.el ends here

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