lisp/net/netrc.el

   1 ;;; netrc.el --- .netrc parsing functionality
   2 ;; Copyright (C) 1996-2018 Free Software Foundation, Inc.
   3
   4 ;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org>
   5 ;; Keywords: news
   6 ;;
   7 ;;  Modularized by Ted Zlatanov <tzz@lifelogs.com>
   8 ;;  when it was part of Gnus.
   9
  10 ;; This file is part of GNU Emacs.
  11
  12 ;; GNU Emacs is free software: you can redistribute it and/or modify
  13 ;; it under the terms of the GNU General Public License as published by
  14 ;; the Free Software Foundation, either version 3 of the License, or
  15 ;; (at your option) any later version.
  16
  17 ;; GNU Emacs is distributed in the hope that it will be useful,
  18 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  19 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20 ;; GNU General Public License for more details.
  21
  22 ;; You should have received a copy of the GNU General Public License
  23 ;; along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.
  24
  25 ;;; Commentary:
  26
  27 ;; Just the .netrc parsing functionality, abstracted so other packages
  28 ;; besides Gnus can use it.
  29
  30 ;;; Code:
  31
  32 ;;;
  33 ;;; .netrc and .authinfo rc parsing
  34 ;;;
  35
  36 (defgroup netrc nil
  37  "Netrc configuration."
  38  :group 'comm)
  39
  40 (defcustom netrc-file "~/.authinfo"
  41   "File where user credentials are stored."
  42   :version "24.1"
  43   :type 'file
  44   :group 'netrc)
  45
  46 (defvar netrc-services-file "/etc/services"
  47   "The name of the services file.")
  48
  49 (defvar netrc-cache nil)
  50
  51 (defun netrc-parse (&optional file)
  52   (interactive "fFile to Parse: ")
  53   "Parse FILE and return a list of all entries in the file."
  54   (unless file
  55     (setq file netrc-file))
  56   (if (listp file)
  57       ;; We got already parsed contents; just return it.
  58       file
  59     (when (file-exists-p file)
  60       (with-temp-buffer
  61         (let ((tokens '("machine" "default" "login"
  62                         "password" "account" "macdef" "force"
  63                         "port"))
  64               alist elem result pair)
  65           (if (and netrc-cache
  66                    (equal (car netrc-cache) (nth 5 (file-attributes file))))
  67               (insert (base64-decode-string (rot13-string (cdr netrc-cache))))
  68             (insert-file-contents file)
  69             (when (string-match "\\.gpg\\'" file)
  70               ;; Store the contents of the file heavily encrypted in memory.
  71               (setq netrc-cache (cons (nth 5 (file-attributes file))
  72                                       (rot13-string
  73                                        (base64-encode-string
  74                                         (buffer-string)))))))
  75           (goto-char (point-min))
  76           ;; Go through the file, line by line.
  77           (while (not (eobp))
  78             (narrow-to-region (point) (point-at-eol))
  79             ;; For each line, get the tokens and values.
  80             (while (not (eobp))
  81               (skip-chars-forward "\t ")
  82               ;; Skip lines that begin with a "#".
  83               (if (eq (char-after) ?#)
  84                   (goto-char (point-max))
  85                 (unless (eobp)
  86                   (setq elem
  87                         (if (= (following-char) ?\")
  88                             (read (current-buffer))
  89                           (buffer-substring
  90                            (point) (progn (skip-chars-forward "^\t ")
  91                                           (point)))))
  92                   (cond
  93                    ((equal elem "macdef")
  94                     ;; We skip past the macro definition.
  95                     (widen)
  96                     (while (and (zerop (forward-line 1))
  97                                 (looking-at "$")))
  98                     (narrow-to-region (point) (point)))
  99                    ((member elem tokens)
 100                     ;; Tokens that don't have a following value are ignored,
 101                     ;; except "default".
 102                     (when (and pair (or (cdr pair)
 103                                         (equal (car pair) "default")))
 104                       (push pair alist))
 105                     (setq pair (list elem)))
 106                    (t
 107                     ;; Values that haven't got a preceding token are ignored.
 108                     (when pair
 109                       (setcdr pair elem)
 110                       (push pair alist)
 111                       (setq pair nil)))))))
 112             (when alist
 113               (push (nreverse alist) result))
 114             (setq alist nil
 115                   pair nil)
 116             (widen)
 117             (forward-line 1))
 118           (nreverse result))))))
 119
 120 (defun netrc-machine (list machine &optional port defaultport)
 121   "Return the netrc values from LIST for MACHINE or for the default entry.
 122 If PORT specified, only return entries with matching port tokens.
 123 Entries without port tokens default to DEFAULTPORT."
 124   (let ((rest list)
 125         result)
 126     (while list
 127       (when (equal (cdr (assoc "machine" (car list))) machine)
 128         (push (car list) result))
 129       (pop list))
 130     (unless result
 131       ;; No machine name matches, so we look for default entries.
 132       (while rest
 133         (when (assoc "default" (car rest))
 134           (let ((elem (car rest)))
 135             (setq elem (delete (assoc "default" elem) elem))
 136             (push elem result)))
 137         (pop rest)))
 138     (when result
 139       (setq result (nreverse result))
 140       (if (not port)
 141           (car result)
 142         (while (and result
 143                     (not (netrc-port-equal
 144                           (or port defaultport "nntp")
 145                           ;; when port is not given in the netrc file,
 146                           ;; it should mean "any port"
 147                           (or (netrc-get (car result) "port")
 148                               defaultport port))))
 149           (pop result))
 150         (car result)))))
 151
 152 (defun netrc-machine-user-or-password (mode authinfo-file-or-list machines ports defaults)
 153   "Get the user name or password according to MODE from AUTHINFO-FILE-OR-LIST.
 154 Matches a machine from MACHINES and a port from PORTS, giving
 155 default ports DEFAULTS to `netrc-machine'.
 156
 157 MODE can be \"login\" or \"password\", suitable for passing to
 158 `netrc-get'."
 159   (let ((authinfo-list (if (stringp authinfo-file-or-list)
 160                            (netrc-parse authinfo-file-or-list)
 161                          authinfo-file-or-list))
 162         (ports (or ports '(nil)))
 163         (defaults (or defaults '(nil)))
 164         info)
 165     (if (listp mode)
 166         (setq info
 167               (mapcar
 168                (lambda (mode-element)
 169                  (netrc-machine-user-or-password
 170                   mode-element
 171                   authinfo-list
 172                   machines
 173                   ports
 174                   defaults))
 175                mode))
 176       (dolist (machine machines)
 177         (dolist (default defaults)
 178           (dolist (port ports)
 179             (let ((alist (netrc-machine authinfo-list machine port default)))
 180               (setq info (or (netrc-get alist mode) info)))))))
 181     info))
 182
 183 (defun netrc-get (alist type)
 184   "Return the value of token TYPE from ALIST."
 185   (cdr (assoc type alist)))
 186
 187 (defun netrc-port-equal (port1 port2)
 188   (when (numberp port1)
 189     (setq port1 (or (netrc-find-service-name port1) port1)))
 190   (when (numberp port2)
 191     (setq port2 (or (netrc-find-service-name port2) port2)))
 192   (equal port1 port2))
 193
 194 (defun netrc-parse-services ()
 195   (when (file-exists-p netrc-services-file)
 196     (let ((services nil))
 197       (with-temp-buffer
 198         (insert-file-contents netrc-services-file)
 199         (while (search-forward "#" nil t)
 200           (delete-region (1- (point)) (point-at-eol)))
 201         (goto-char (point-min))
 202         (while (re-search-forward
 203                 "^ *\\([^ \n\t]+\\)[ \t]+\\([0-9]+\\)/\\([^ \t\n]+\\)" nil t)
 204           (push (list (match-string 1) (string-to-number (match-string 2))
 205                       (intern (downcase (match-string 3))))
 206                 services))
 207         (nreverse services)))))
 208
 209 (defun netrc-find-service-name (number &optional type)
 210   (let ((services (netrc-parse-services))
 211         service)
 212     (setq type (or type 'tcp))
 213     (while (and (setq service (pop services))
 214                 (not (and (= number (cadr service))
 215                           (eq type (car (cddr service)))))))
 216     (car service)))
 217
 218 ;;;###autoload
 219 (defun netrc-credentials (machine &rest ports)
 220   "Return a user name/password pair.
 221 Port specifications will be prioritized in the order they are
 222 listed in the PORTS list."
 223   (let ((list (netrc-parse))
 224         found)
 225     (if (not ports)
 226         (setq found (netrc-machine list machine))
 227       (while (and ports
 228                   (not found))
 229         (setq found (netrc-machine list machine (pop ports)))))
 230     (when found
 231       (list (cdr (assoc "login" found))
 232             (cdr (assoc "password" found))))))
 233
 234 (provide 'netrc)
 235
 236 ;;; netrc.el ends here