inetutils/telnet/terminal.c

/*
  Copyright (C) 1995-2025 Free Software Foundation, Inc.

  This file is part of GNU Inetutils.

  GNU Inetutils 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 3 of the License, or (at
  your option) any later version.

  GNU Inetutils 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, see `http://www.gnu.org/licenses/'. */

/*
 * Copyright (c) 1988, 1990, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <config.h>

#include <stdlib.h>

#include <arpa/telnet.h>
#include <sys/types.h>

#include "ring.h"

#include "externs.h"
#include "types.h"

#ifdef  ENCRYPTION
# include <libtelnet/encrypt.h>
#endif

Ring ttyoring, ttyiring;
unsigned char ttyobuf[2 * BUFSIZ], ttyibuf[BUFSIZ];

int termdata;			/* Debugging flag */

#ifdef	USE_TERMIO
# ifndef VDISCARD
cc_t termFlushChar;
# endif
# ifndef VLNEXT
cc_t termLiteralNextChar;
# endif
# ifndef VSUSP
cc_t termSuspChar;
# endif
# ifndef VWERASE
cc_t termWerasChar;
# endif
# ifndef VREPRINT
cc_t termRprntChar;
# endif
# ifndef VSTART
cc_t termStartChar;
# endif
# ifndef VSTOP
cc_t termStopChar;
# endif
# ifndef VEOL
cc_t termForw1Char;
# endif
# ifndef VEOL2
cc_t termForw2Char;
# endif
# ifndef VSTATUS
cc_t termAytChar;
# endif
#else
cc_t termForw2Char;
cc_t termAytChar;
#endif

/*
 * initialize the terminal data structures.
 */

void
init_terminal (void)
{
  if (ring_init (&ttyoring, ttyobuf, sizeof ttyobuf) != 1)
    {
      exit (EXIT_FAILURE);
    }
  if (ring_init (&ttyiring, ttyibuf, sizeof ttyibuf) != 1)
    {
      exit (EXIT_FAILURE);
    }
  autoflush = TerminalAutoFlush ();
}


/*
 *		Send as much data as possible to the terminal.
 *
 *		Return value:
 *			-1: No useful work done, data waiting to go out.
 *			 0: No data was waiting, so nothing was done.
 *			 1: All waiting data was written out.
 *			 n: All data - n was written out.
 */


int
ttyflush (int drop)
{
  int n, n0, n1;

  n0 = ring_full_count (&ttyoring);
  if ((n1 = n = ring_full_consecutive (&ttyoring)) > 0)
    {
      if (drop)
	{
	  TerminalFlushOutput ();
	  /* we leave 'n' alone! */
	}
      else
	{
	  n = TerminalWrite ((char *) ttyoring.consume, n);
	}
    }
  if (n > 0)
    {
      if (termdata && n)
	{
	  Dump ('>', ttyoring.consume, n);
	}
      /*
       * If we wrote everything, and the full count is
       * larger than what we wrote, then write the
       * rest of the buffer.
       */
      if (n1 == n && n0 > n)
	{
	  n1 = n0 - n;
	  if (!drop)
	    n1 = TerminalWrite ((char *) ttyoring.bottom, n1);
	  if (n1 > 0)
	    n += n1;
	}
      ring_consumed (&ttyoring, n);
    }
  if (n < 0)
    return -1;
  if (n == n0)
    {
      if (n0)
	return -1;
      return 0;
    }
  return n0 - n + 1;
}


/*
 * These routines decides on what the mode should be (based on the values
 * of various global variables).
 */


int
getconnmode (void)
{
  extern int linemode;
  int mode = 0;
#ifdef	KLUDGELINEMODE
  extern int kludgelinemode;
#endif

  if (In3270)
    return (MODE_FLOW);

  if (my_want_state_is_dont (TELOPT_ECHO))
    mode |= MODE_ECHO;

  if (localflow)
    mode |= MODE_FLOW;

  if (my_want_state_is_will (TELOPT_BINARY))
    mode |= MODE_INBIN;

  if (his_want_state_is_will (TELOPT_BINARY))
    mode |= MODE_OUTBIN;

#ifdef	KLUDGELINEMODE
  if (kludgelinemode)
    {
      if (my_want_state_is_dont (TELOPT_SGA))
	{
	  mode |= (MODE_TRAPSIG | MODE_EDIT);
	  if (dontlecho && (clocks.echotoggle > clocks.modenegotiated))
	    {
	      mode &= ~MODE_ECHO;
	    }
	}
      return (mode);
    }
#endif
  if (my_want_state_is_will (TELOPT_LINEMODE))
    mode |= linemode;
  return (mode);
}

void
setconnmode (int force)
{
#ifdef	ENCRYPTION
  static int enc_passwd = 0;
#endif /* ENCRYPTION */
  int newmode;

  newmode = getconnmode () | (force ? MODE_FORCE : 0);

  TerminalNewMode (newmode);

#ifdef  ENCRYPTION
  if ((newmode & (MODE_ECHO | MODE_EDIT)) == MODE_EDIT)
    {
      if (my_want_state_is_will (TELOPT_ENCRYPT)
	  && (enc_passwd == 0) && !encrypt_output)
	{
	  encrypt_request_start (0, 0);
	  enc_passwd = 1;
	}
    }
  else
    {
      if (enc_passwd)
	{
	  encrypt_request_end ();
	  enc_passwd = 0;
	}
    }
#endif /* ENCRYPTION */

}


void
setcommandmode (void)
{
  TerminalNewMode (-1);
}