xref: /src/usr.bin/telnet/terminal.c

/*	$NetBSD: terminal.c,v 1.16 2018/12/14 06:08:18 maya Exp $	*/

/*
 * 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 <sys/cdefs.h>
#ifndef lint
#if 0
static char sccsid[] = "@(#)terminal.c	8.2 (Berkeley) 2/16/95";
#else
__RCSID("$NetBSD: terminal.c,v 1.16 2018/12/14 06:08:18 maya Exp $");
#endif
#endif /* not lint */

#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];
char line[] = { '\0' };

int termdata;			/* Debugging flag */

/*
 * initialize the terminal data structures.
 */

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


/*
 *		Send as much data as possible to the terminal, else exits if
 *		it encounters a permanent failure when writing to the tty.
 *
 *		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(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(ttyoring.bottom, n1);
		if (n1 > 0)
			n += n1;
	}
	ring_consumed(&ttyoring, n);
    }
    if (n < 0) {
	if (errno == EAGAIN || errno == EINTR) {
	    return -1;
	} else {
	    ring_consumed(&ttyoring, ring_full_count(&ttyoring));
	    setconnmode(0);
	    setcommandmode();
	    NetClose(net);
	    fprintf(stderr, "Connection closed by foreign host.\n");
	    exit(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 (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
    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);
}