;;; rlogin.el --- remote login interface

;; Author: Noah Friedman
;; Maintainer: Noah Friedman <friedman@prep.ai.mit.edu>
;; Keywords: unix, comm

;; Copyright (C) 1992, 1993, 1994 Free Software Foundation, Inc.
;;
;; 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, 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.; 675 Massachusetts Avenue.; Cambridge, MA 02139, USA.

;;; Commentary:

;; Support for remote logins using `rlogin'.
;; $Id: rlogin.el,v 1.19 1994/09/19 11:47:05 pot Exp rms $

;; If you wish for rlogin mode to prompt you in the minibuffer for
;; passwords when a password prompt appears, just enter m-x send-invisible
;; and type in your line, or add `comint-watch-for-password-prompt' to
;; `comint-output-filter-functions'.

;;; Code:

(require 'comint)
(require 'shell)

;;;###autoload
(defvar rlogin-program "rlogin"
  "*Name of program to invoke rlogin")

;;;###autoload
(defvar rlogin-explicit-args nil
  "*List of arguments to pass to rlogin on the command line.")

;;;###autoload
(defvar rlogin-mode-hook nil
  "*Hooks to run after setting current buffer to rlogin-mode.")

;;;###autoload
(defvar rlogin-process-connection-type nil
  "*If non-`nil', use a pty for the local rlogin process.  
If `nil', use a pipe (if pipes are supported on the local system).  

Generally it is better not to waste ptys on systems which have a static
number of them.  On the other hand, some implementations of `rlogin' assume
a pty is being used, and errors will result from using a pipe instead.")

;;;###autoload
(defvar rlogin-initially-track-cwd t
  "*If non-`nil', do remote directory tracking via ange-ftp right away.
If `nil', you can still enable directory tracking by doing 
`M-x dirtrack-toggle'.")

;; Initialize rlogin mode map.
(defvar rlogin-mode-map '())
(cond ((not rlogin-mode-map)
       (setq rlogin-mode-map (cons 'keymap shell-mode-map)) 
       (define-key rlogin-mode-map "\C-c\C-c" 'rlogin-send-Ctrl-C)
       (define-key rlogin-mode-map "\C-c\C-d" 'rlogin-send-Ctrl-D)
       (define-key rlogin-mode-map "\C-c\C-z" 'rlogin-send-Ctrl-Z)
       (define-key rlogin-mode-map "\C-c\C-\\" 'rlogin-send-Ctrl-backslash)
       (define-key rlogin-mode-map "\C-d" 'rlogin-delchar-or-send-Ctrl-D)))

;;;###autoload
(defun rlogin (input-args &optional prefix)
  "Open a network login connection to HOST via the `rlogin' program.
Input is sent line-at-a-time to the remote connection.

Communication with the remote host is recorded in a buffer *rlogin-HOST*,
where HOST is the first word in the string ARGS.  If a prefix argument is
given and the buffer *rlogin-HOST* already exists, a new buffer with a
different connection will be made.

The variable `rlogin-program' contains the name of the actual program to
run.  It can be a relative or absolute path. 

The variable `rlogin-explicit-args' is a list of arguments to give to
the rlogin when starting.  They are added after any arguments given in ARGS.

If `rlogin-initially-track-cwd' is non-nil (which is true by default),
then the default directory in that buffer is set to a remote (FTP) file name
to access your home directory on the remote machine.  Occasionally
this causes an error, if you cannot access the home directory on that
machine.  This error is harmless as long as you don't try to use
that default directory."
  (interactive (list
		(read-from-minibuffer "rlogin arguments (hostname first): ")
		current-prefix-arg))
  (let* ((process-connection-type rlogin-process-connection-type)
         (buffer-name (format "*rlogin-%s*" input-args))
         args
	 host
	 user
	 proc
         (old-match-data (match-data)))
    (while (string-match "[ \t]*\\([^ \t]+\\)$" input-args)
      (setq args (cons (substring input-args
				  (match-beginning 1) (match-end 1))
		       args)
            input-args (substring input-args 0 (match-beginning 0))))
    (store-match-data old-match-data)
    (setq args (append args rlogin-explicit-args))
    (setq host (car args))
    (let ((tmpargs (cdr args)))
      (while (and tmpargs
		  (not (string= (car tmpargs) "-l")))
	(setq tmpargs (cdr tmpargs)))
      (setq user (car (cdr tmpargs))))
    (setq buffer-name (format "*rlogin-%s*" host))
    (and prefix (setq buffer-name 
                      (buffer-name (generate-new-buffer buffer-name))))
    (switch-to-buffer buffer-name)
    (or (comint-check-proc buffer-name)
        (progn
          (comint-mode)
          (comint-exec (current-buffer) buffer-name rlogin-program nil args)
          (setq proc (get-process buffer-name))
          ;; Set process-mark to point-max in case there is text in the
          ;; buffer from a previous exited process.
          (set-marker (process-mark proc) (point-max))
          (rlogin-mode)
          ;; Set the prefix for filename completion and directory tracking
          ;; to find the remote machine's files by ftp.
          (setq comint-file-name-prefix (concat "/"
						(and user (concat user "@"))
						host ":"))
          (and rlogin-initially-track-cwd
               ;; Presume the user will start in his remote home directory.
               ;; If this is wrong, M-x dirs will fix it.
               (cd-absolute (concat "/"
				    (and user (concat user "@"))
				    host ":~/")))))))
(defun rlogin-mode ()
  "Set major-mode for rlogin sessions. 
If `rlogin-mode-hook' is set, run it."
  (interactive)
  (kill-all-local-variables)
  (shell-mode)
  (setq major-mode 'rlogin-mode)
  (setq mode-name "rlogin")
  (use-local-map rlogin-mode-map)
  (setq shell-dirtrackp rlogin-initially-track-cwd)
  (make-local-variable 'comint-file-name-prefix)
  (run-hooks 'rlogin-mode-hook))


(defun rlogin-send-Ctrl-C ()
  (interactive)
  (send-string nil "\C-c"))

(defun rlogin-send-Ctrl-D ()
  (interactive)
  (send-string nil "\C-d"))

(defun rlogin-send-Ctrl-Z ()
  (interactive)
  (send-string nil "\C-z"))

(defun rlogin-send-Ctrl-backslash ()
  (interactive)
  (send-string nil "\C-\\"))

(defun rlogin-delchar-or-send-Ctrl-D (arg)
  "\
Delete ARG characters forward, or send a C-d to process if at end of buffer."  
  (interactive "p") 
  (if (eobp)
      (rlogin-send-Ctrl-D)
    (delete-char arg)))

;;; rlogin.el ends here