terminal.c

linux下c语言编写的telnet客户端程序

/*	$OpenBSD: terminal.c,v 1.3 1998/03/12 04:57:45 art Exp $	*/
/*	$NetBSD: terminal.c,v 1.5 1996/02/28 21:04:17 thorpej 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. 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 "telnet_locl.h"

Ring		ttyoring, ttyiring;
unsigned char	ttyobuf[2*BUFSIZ], ttyibuf[BUFSIZ]; //BUFSIZ的值为8192

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(1);
    }
    if (ring_init(&ttyiring, ttyibuf, sizeof ttyibuf) != 1) {
	exit(1);
    }
    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)
{
    register 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(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).
 */

extern int linemode;
#ifdef	KLUDGELINEMODE
extern int kludgelinemode;
#endif

    int
getconnmode(void)
{
    int mode = 0;

    if (In3270)
	return(MODE_FLOW);

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

    if (localflow)
	mode |= MODE_FLOW;

    if ((eight & 1) || my_want_state_is_will(TELOPT_BINARY))
	mode |= MODE_INBIN;

    if (eight & 2)
	mode |= MODE_OUT8;
    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)
{
    register int newmode;
#ifdef ENCRYPTION
    static int enc_passwd = 0;
#endif

    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

}


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