#! /usr/local/bin/guile -s
!#
;;;; This is Scheme whoisd daemon
;;;; Copyright (C) 2002, Sergey Poznyakoff
;;;;
;;;; This program is free software; you can redistribute it and/or modify
;;;; it under the terms of the GNU General Public License as published by
;;;; the Free Software Foundation; either version 2 of the License, or
;;;; (at your option) any later version.
;;;;
;;;; This program is distributed in the hope that it will be useful,
;;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;;;; GNU General Public License for more details.
;;;;
;;;; You should have received a copy of the GNU General Public License
;;;; along with this program; if not, write to the Free Software
;;;; Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
;;;;

(set! %load-path (append %load-path (list "/usr/local/lib/guile")))
(use-modules (ice-9 getopt-long))
(use-modules (util sql))

;;; User-definable variables
(define sql-iface "mysql")
(define sql-host "")
(define sql-port 3306)
(define sql-database "whois")
(define sql-username "whois")
(define sql-password "secret")
;;; End of user-definable variables

(define progname "whoisd")
(define debug-level 0)

(define (debug level . text)
  (if (<= level debug-level)
        (map (lambda (x)
               (display x (current-error-port)))
             (append
              (list
               (if foreground-mode
                   progname
                   (strftime "%c" (localtime (current-time))))
               ":debug:" (number->string level) ": ")
              text
              (list "\n")))))

(define (convert-date date)
  (string-append (substring date 0 4)
                 (substring date 5 7)
                 (substring date 8)))

(define (display-list prefix data port)
  (for-each
   (lambda (x)
     (if (pair? x)
       (display-list prefix x port)
       (begin
         (display prefix port)
         (display ": " port)
         (display x port)
         (newline port))))
   data))

(define (multiline->list str)
  (let loop ((fields '())
             (str str))
    (cond
     ((string-index str #\newline)
      => (lambda (w)
           (loop
            (append fields (list (substring str 0 w)))
            (substring str (1+ w)))))
     ((= (string-length str) 0)
      fields)
     (else
      (append fields (list str))))))
  
(define (display-multiline prefix text port)
  (if text
      (display-list prefix (multiline->list text) port)))

(define (whois-error port code . text)
  (display-list (string-append "%ERROR:"
                               (number->string code))
                text port))

(define (whois-query port conn key)
  (debug 2 "key " key)
  (let ((dom-res (sql-query conn (string-append
                                  "SELECT \
domain,descr,remark,created,changed,changed_by,source \
FROM domain WHERE domain=\"" key "\"")))
        (admin-c (sql-query conn (string-append
                                  "SELECT contact FROM admin_c \
WHERE domain=\"" key "\"")))
        (tech-c (sql-query conn (string-append
                                 "SELECT contact FROM tech_c \
WHERE domain=\"" key "\"")))
        (zone-c (sql-query conn (string-append
                                 "SELECT contact FROM zone_c \
WHERE domain=\"" key "\"")))
        (nserver (sql-query conn (string-append
                                  "SELECT nserver FROM nserver \
WHERE domain=\"" key "\""))))
    (debug 2 "result: " dom-res)
    (if (null? dom-res)
        (whois-error port 100 "No entries found")
        (let ((dr (car dom-res)))
          (display "domain: " port)(display (car dr) port)(newline port)
          (display-multiline "descr" (list-ref dr 1) port)
          (display-multiline "remark" (list-ref dr 2) port)
          (display-list "admin-c" admin-c port)
          (display-list "tech-c" tech-c port)
          (display-list "zone-c" zone-c port)
          (display-list "nserver" nserver port)
          (display (string-append
                    "changed: "
                    (list-ref dr 5)
                    " "
                    (convert-date (list-ref dr 4))) port)
          (newline port)
          (display "source: " port)
          (display (list-ref dr 6) port)
          (newline port)
          (newline port)
          (force-output port))))) 

(define whois-standalone #t)
(define single-process #f)
(define foreground-mode #f)
(define whois-address INADDR_ANY)
(define whois-port 43)
(define max-children 10)
(define num-children 0)

(define whoisd-idle-timeout 5)
(define whoisd-gid -1)
(define whoisd-uid -1)

(define whoisd-user "daemon")

(define (sigalrm-handler sig)
  (debug 1 "Timed out in waiting for input")
  (exit 1))

(define (read-or-timeout port)
  (sigaction SIGALRM sigalrm-handler)
  (alarm whoisd-idle-timeout)
  (do ()
      ((char-ready? port) #f))
  (let ((value (read-line port)))
    (sigaction SIGALRM SIG_IGN)
    value))

(define (whois-server in out . rest)
  (if (not (null? rest))
      (let ((conn-info (car rest)))
        (debug 1 "Connect from " (inet-ntoa (vector-ref conn-info 1)))))
  (let ((key (read-or-timeout in))
        (conn (sql-connect
               sql-iface sql-host sql-port sql-database
               sql-username sql-password)))
    (cond
     (conn
      (whois-query out conn key)
      (sql-connect-close conn))
     (else
      (whois-error out 500 "Database is not available")))))

(define (sigchld-handler sig)
  (catch 'system-error
         (lambda ()
           (do ((pid (waitpid WAIT_ANY WNOHANG) (waitpid WAIT_ANY WNOHANG)))
               ((= (car pid) 0) #f)
             (debug 1 "Child " (car pid) " terminated with code " (cdr pid))
             (set! num-children (1- num-children))))
         (lambda args #f)))


(define (ready-for-reading? fd)
  (catch 'system-error
         (lambda ()
           (let ((r (select (list fd) '() '()  1)))
             (member fd (car r))))
         (lambda args #f)))

(define (whois-mainloop)
  (let ((socket (socket AF_INET SOCK_STREAM 0)))
    (bind socket AF_INET whois-address whois-port)
    (if (not foreground-mode)
        (begin
         (setgid whoisd-gid)
         (setuid whoisd-uid)))
    (sigaction SIGCHLD sigchld-handler SA_RESTART)
    (listen socket 5)
    (do ()
        (#f #f)
      (if (or (= 0 num-children)
              (ready-for-reading? socket))
          (let ((conn (accept socket)))
            (cond
             ((>= num-children max-children)
              (debug 1 "Too many connections active (" num-children ")")
              (whois-error (car conn) 501 "Too many connections active"))
             (else
              (let ((pid (primitive-fork)))
                (cond
                 ((= pid 0)
                  (close-port socket)
                  (whois-server (car conn) (car conn) (cdr conn))
                  (shutdown (car conn) 2)
                  (exit 0))
                 (else
                  (set! num-children (1+ num-children))
                  (debug 1 "Child " pid " started. Total "
                         num-children "."))))))
            (close-port (car conn)))))))

(define (whois-daemon)
  (close-all-ports-except (current-error-port))
  (sigaction SIGCHLD SIG_IGN)
  (case foreground-mode
    ((#f)
     (let ((pid (primitive-fork)))
       (cond
        ((= pid 0)
         (chdir "/")
         (setsid)
         (whois-mainloop))
        (else
         (debug 10 "Started child " pid)
         (primitive-exit)))))
    ((#t)
     (whois-mainloop))))

(define grammar
  `((help (single-char #\h)
          (value #f))
    (single (single-char #\s)
            (value #f))
    (foreground (single-char #\f)
                (value #f))
    (debug (single-char #\x)
           (value #t))
    (inetd (single-char #\i)
           (value #f))
    (daemon (single-char #\d)
            (value #t))
    (ip-address (single-char #\a)
                (value #t))
    (port (single-char #\p)
          (value #t))
    (timeout (single-char #\t)
             (value #t))
    (user (single-char #\u)
          (value #t))))

(define (print-help)
  (display "\
Usage: whoisd [OPTIONS]\n\
whoisd -- The whois daemon.\n\
\n\
-h, --help               Display this help\n\
-x, --debug VALUE        Set debugging level\n\
-t, --timeout            Set idle timeout for a request\n\
\n\
-i, --inetd              Run in inetd mode.\n\
\n\
-d, --daemon NUMBER      Run in daemon mode. Limit number of children spawned\n\
                         simultaneously to NUMBER. This is the default mode,\n\
                         NUMBER defaults to 10.\n\
\n\
The following options may be used in daemon mode only:\n\
\n\
-s, --single             Single-process mode: do not spawn children\n\
                         for handling requests.\n\
-f, --foreground         Stay in foreground.\n\
-a, --ip-address ADDRESS Listen on this IP address\n\
-p, --port NUMBER        Listen on this port number.\n\
-u, --user USER          Run with this user privileges. Default is \"daemon\"\n\
"))
          
;; Parse command line

(for-each
 (lambda (x)
   (and (pair? x)
        (case (car x)
          ((help)
           (print-help)
           (exit 0))
          ((port)
           (set! whois-port (string->number (cdr x))))
          ((ip-address)
           (set! whois-address (inet-aton (cdr x))))
          ((debug)
           (set! debug-level (string->number (cdr x))))
          ((daemon)
           (set! max-children (string->number (cdr x))))
          ((single)
           (set! single-process (cdr x)))
          ((foreground)
           (set! foreground-mode (cdr x)))
          ((user)
           (set! whoisd-user (cdr x)))
          ((timeout)
           (set! whoisd-idle-timeout (string->number (cdr x))))
          ((inetd)
           (set! whois-standalone (not (cdr x)))))))
 (getopt-long (command-line) grammar))

(let ((pwd (getpwnam whoisd-user)))
  (set! whoisd-uid (vector-ref pwd 2))
  (set! whoisd-gid (vector-ref pwd 3)))

(if whois-standalone
   (whois-daemon)
   (whois-server (current-input-port) (current-output-port)))