lisp/net/dig.el

   1 ;;; dig.el --- Domain Name System dig interface
   2
   3 ;; Copyright (C) 2000-2015 Free Software Foundation, Inc.
   4
   5 ;; Author: Simon Josefsson <simon@josefsson.org>
   6 ;; Keywords: DNS BIND dig comm
   7
   8 ;; This file is part of GNU Emacs.
   9
  10 ;; GNU Emacs is free software: you can redistribute it and/or modify
  11 ;; it under the terms of the GNU General Public License as published by
  12 ;; the Free Software Foundation, either version 3 of the License, or
  13 ;; (at your option) any later version.
  14
  15 ;; GNU Emacs is distributed in the hope that it will be useful,
  16 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 ;; GNU General Public License for more details.
  19
  20 ;; You should have received a copy of the GNU General Public License
  21 ;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
  22
  23 ;;; Commentary:
  24
  25 ;; This provide an interface for "dig".
  26 ;;
  27 ;; For interactive use, try M-x dig and type a hostname.  Use `q' to quit
  28 ;; dig buffer.
  29 ;;
  30 ;; For use in elisp programs, call `dig-invoke' and use
  31 ;; `dig-extract-rr' to extract resource records.
  32
  33 ;;; Release history:
  34
  35 ;; 2000-10-28  posted on gnu.emacs.sources
  36
  37 ;;; Code:
  38
  39 (eval-when-compile (require 'cl))
  40
  41 (defgroup dig nil
  42   "Dig configuration."
  43   :group 'comm)
  44
  45 (defcustom dig-program "dig"
  46   "Name of dig (domain information groper) binary."
  47   :type 'file
  48   :group 'dig)
  49
  50 (defcustom dig-dns-server nil
  51   "DNS server to query.
  52 If nil, use system defaults."
  53   :type '(choice (const :tag "System defaults")
  54                  string)
  55   :group 'dig)
  56
  57 (defcustom dig-font-lock-keywords
  58   '(("^;; [A-Z]+ SECTION:" 0 font-lock-keyword-face)
  59     ("^;;.*" 0 font-lock-comment-face)
  60     ("^; <<>>.*" 0 font-lock-type-face)
  61     ("^;.*" 0 font-lock-function-name-face))
  62   "Default expressions to highlight in dig mode."
  63   :type 'sexp
  64   :group 'dig)
  65
  66 (defun dig-invoke (domain &optional
  67                           query-type query-class query-option
  68                           dig-option server)
  69   "Call dig with given arguments and return buffer containing output.
  70 DOMAIN is a string with a DNS domain.  QUERY-TYPE is an optional
  71 string with a DNS type.  QUERY-CLASS is an optional string with a DNS
  72 class.  QUERY-OPTION is an optional string with dig \"query options\".
  73 DIG-OPTION is an optional string with parameters for the dig program.
  74 SERVER is an optional string with a domain name server to query.
  75
  76 Dig is an external program found in the BIND name server distribution,
  77 and is a commonly available debugging tool."
  78   (let (buf cmdline)
  79     (setq buf (generate-new-buffer "*dig output*"))
  80     (if dig-option (push dig-option cmdline))
  81     (if query-option (push query-option cmdline))
  82     (if query-class (push query-class cmdline))
  83     (if query-type (push query-type cmdline))
  84     (push domain cmdline)
  85     (if server (push (concat "@" server) cmdline)
  86       (if dig-dns-server (push (concat "@" dig-dns-server) cmdline)))
  87     (apply 'call-process dig-program nil buf nil cmdline)
  88     buf))
  89
  90 (defun dig-extract-rr (domain &optional type class)
  91   "Extract resource records for DOMAIN, TYPE and CLASS from buffer.
  92 Buffer should contain output generated by `dig-invoke'."
  93   (save-excursion
  94     (goto-char (point-min))
  95     (if (re-search-forward
  96          (concat domain "\\.?[\t ]+[0-9wWdDhHmMsS]+[\t ]+"
  97                  (upcase (or class "IN")) "[\t ]+" (upcase (or type "A")))
  98          nil t)
  99         (let (b e)
 100           (end-of-line)
 101           (setq e (point))
 102           (beginning-of-line)
 103           (setq b (point))
 104           (when (search-forward " (" e t)
 105             (search-forward " )"))
 106           (end-of-line)
 107           (setq e (point))
 108           (buffer-substring b e))
 109       (and (re-search-forward (concat domain "\\.?[\t ]+[0-9wWdDhHmMsS]+[\t ]+"
 110                                       (upcase (or class "IN"))
 111                                       "[\t ]+CNAME[\t ]+\\(.*\\)$") nil t)
 112            (dig-extract-rr (match-string 1) type class)))))
 113
 114 (defun dig-rr-get-pkix-cert (rr)
 115   (let (b e str)
 116     (string-match "[^\t ]+[\t ]+[0-9wWdDhHmMsS]+[\t ]+IN[\t ]+CERT[\t ]+\\(1\\|PKIX\\)[\t ]+[0-9]+[\t ]+[0-9]+[\t ]+(?" rr)
 117     (setq b (match-end 0))
 118     (string-match ")" rr)
 119     (setq e (match-beginning 0))
 120     (setq str (substring rr b e))
 121     (while (string-match "[\t \n\r]" str)
 122       (setq str (replace-match "" nil nil str)))
 123     str))
 124
 125 ;; XEmacs does it like this.  For Emacs, we have to set the
 126 ;; `font-lock-defaults' buffer-local variable.
 127 (put 'dig-mode 'font-lock-defaults '(dig-font-lock-keywords t))
 128
 129 (put 'dig-mode 'mode-class 'special)
 130
 131 (defvar dig-mode-map
 132   (let ((map (make-sparse-keymap)))
 133     (suppress-keymap map)
 134     (define-key map "q" 'dig-exit)
 135     map))
 136
 137 (define-derived-mode dig-mode nil "Dig"
 138   "Major mode for displaying dig output."
 139   (buffer-disable-undo)
 140   (unless (featurep 'xemacs)
 141     (set (make-local-variable 'font-lock-defaults)
 142          '(dig-font-lock-keywords t)))
 143   (when (featurep 'font-lock)
 144     ;; FIXME: what is this for??  --Stef
 145     (font-lock-set-defaults))
 146   )
 147
 148 (defun dig-exit ()
 149   "Quit dig output buffer."
 150   (interactive)
 151   (kill-buffer (current-buffer)))
 152
 153 ;;;###autoload
 154 (defun dig (domain &optional
 155                    query-type query-class query-option dig-option server)
 156   "Query addresses of a DOMAIN using dig, by calling `dig-invoke'.
 157 Optional arguments are passed to `dig-invoke'."
 158   (interactive "sHost: ")
 159   (switch-to-buffer
 160    (dig-invoke domain query-type query-class query-option dig-option server))
 161   (goto-char (point-min))
 162   (and (search-forward ";; ANSWER SECTION:" nil t)
 163        (forward-line))
 164   (dig-mode)
 165   (setq buffer-read-only t)
 166   (set-buffer-modified-p nil))
 167
 168 ;; named for consistency with query-dns in dns.el
 169 (defun query-dig (domain &optional
 170                          query-type query-class query-option dig-option server)
 171   "Query addresses of a DOMAIN using dig.
 172 It works by calling `dig-invoke' and `dig-extract-rr'.
 173 Optional arguments are passed to `dig-invoke' and `dig-extract-rr'.
 174 Returns nil for domain/class/type queries that result in no data."
 175 (let ((buffer (dig-invoke domain query-type query-class
 176                           query-option dig-option server)))
 177   (when buffer
 178     (switch-to-buffer buffer)
 179     (let ((digger (dig-extract-rr domain query-type query-class)))
 180       (kill-buffer buffer)
 181       digger))))
 182
 183 (provide 'dig)
 184
 185 ;;; dig.el ends here