termstat.c

linux下telnet服务端的源码实现

	/*
	 * Some things should be deferred until after the pty state has
	 * been set by the local process.  Do those things that have been
	 * deferred now.  This only happens once.
	 */
	if (_terminit == 0) {
		_terminit = 1;
		defer_terminit();
	}

	netflush();
	set_termbuf();
	return;

}  /* end of localstat */

/*
 * flowstat
 *
 * Check for changes to flow control
 */
void
flowstat()
{
	if (his_state_is_will(TELOPT_LFLOW)) {
		if (tty_flowmode() != flowmode) {
			flowmode = tty_flowmode();
			net_output_data ("%c%c%c%c%c%c",
					IAC, SB, TELOPT_LFLOW,
					flowmode ? LFLOW_ON : LFLOW_OFF,
					IAC, SE);
		}
		if (tty_restartany() != restartany) {
			restartany = tty_restartany();
			net_output_data ("%c%c%c%c%c%c",
					IAC, SB, TELOPT_LFLOW,
					restartany ? LFLOW_RESTART_ANY
						   : LFLOW_RESTART_XON,
					IAC, SE);
		}
	}
}

/*
 * clientstat
 *
 * Process linemode related requests from the client.
 * Client can request a change to only one of linemode, editmode or slc's
 * at a time, and if using kludge linemode, then only linemode may be
 * affected.
 */
void
clientstat(register int code, register int parm1, register int parm2)
{
	void netflush();

	/*
	 * Get a copy of terminal characteristics.
	 */
	init_termbuf();

	/*
	 * Process request from client. code tells what it is.
	 */
	switch (code) {
	case TELOPT_LINEMODE:
		/*
		 * Don't do anything unless client is asking us to change
		 * modes.
		 */
		uselinemode = (parm1 == WILL);
		if (uselinemode != linemode) {
			/*
			 * If using kludge linemode, make sure that
			 * we can do what the client asks.
			 * We can not turn off linemode if alwayslinemode
			 * and the ICANON bit is set.
			 */
			if (lmodetype == KLUDGE_LINEMODE) {
				if (alwayslinemode && tty_isediting()) {
					uselinemode = 1;
				}
			}

			/*
			 * Quit now if we can't do it.
			 */
			if (uselinemode == linemode)
				return;

			/*
			 * If using real linemode and linemode is being
			 * turned on, send along the edit mode mask.
			 */
			if (lmodetype == REAL_LINEMODE && uselinemode)
			if (uselinemode)
			{
				useeditmode = 0;
				if (tty_isediting())
					useeditmode |= MODE_EDIT;
				if (tty_istrapsig())
					useeditmode |= MODE_TRAPSIG;
				if (tty_issofttab())
					useeditmode |= MODE_SOFT_TAB;
				if (tty_islitecho())
					useeditmode |= MODE_LIT_ECHO;
				net_output_data ("%c%c%c%c%c%c%c", IAC,
					SB, TELOPT_LINEMODE, LM_MODE,
							useeditmode, IAC, SE);
				editmode = useeditmode;
			}


			tty_setlinemode(uselinemode);

			linemode = uselinemode;

			if (!linemode)
				send_will(TELOPT_ECHO, 1);
		}
		break;

	case LM_MODE:
	    {
		register int ack, changed;

		/*
		 * Client has sent along a mode mask.  If it agrees with
		 * what we are currently doing, ignore it; if not, it could
		 * be viewed as a request to change.  Note that the server
		 * will change to the modes in an ack if it is different from
		 * what we currently have, but we will not ack the ack.
		 */
		 useeditmode &= MODE_MASK;
		 ack = (useeditmode & MODE_ACK);
		 useeditmode &= ~MODE_ACK;

		 if (changed = (useeditmode ^ editmode)) {
			/*
			 * This check is for a timing problem.  If the
			 * state of the tty has changed (due to the user
			 * application) we need to process that info
			 * before we write in the state contained in the
			 * ack!!!  This gets out the new MODE request,
			 * and when the ack to that command comes back
			 * we'll set it and be in the right mode.
			 */
			if (ack)
				localstat();
			if (changed & MODE_EDIT)
				tty_setedit(useeditmode & MODE_EDIT);

			if (changed & MODE_TRAPSIG)
				tty_setsig(useeditmode & MODE_TRAPSIG);

			if (changed & MODE_SOFT_TAB)
				tty_setsofttab(useeditmode & MODE_SOFT_TAB);

			if (changed & MODE_LIT_ECHO)
				tty_setlitecho(useeditmode & MODE_LIT_ECHO);

			set_termbuf();

 			if (!ack) {
 				net_output_data ("%c%c%c%c%c%c%c", IAC,
					SB, TELOPT_LINEMODE, LM_MODE,
 					useeditmode|MODE_ACK,
 					IAC, SE);
 			}

			editmode = useeditmode;
		}

		break;

	    }  /* end of case LM_MODE */

	case TELOPT_NAWS:
#ifdef	TIOCSWINSZ
	    {
		struct winsize ws;

		def_col = parm1;
		def_row = parm2;
		/*
		 * Defer changing window size until after terminal is
		 * initialized.
		 */
		if (terminit() == 0)
			return;

		/*
		 * Change window size as requested by client.
		 */

		ws.ws_col = parm1;
		ws.ws_row = parm2;
		(void) ioctl(pty, TIOCSWINSZ, (char *)&ws);
	    }
#endif	/* TIOCSWINSZ */

		break;

	case TELOPT_TSPEED:
	    {
		def_tspeed = parm1;
		def_rspeed = parm2;
		/*
		 * Defer changing the terminal speed.
		 */
		if (terminit() == 0)
			return;
		/*
		 * Change terminal speed as requested by client.
		 * We set the receive speed first, so that if we can't
		 * store seperate receive and transmit speeds, the transmit
		 * speed will take precedence.
		 */
		tty_rspeed(parm2);
		tty_tspeed(parm1);
		set_termbuf();

		break;

	    }  /* end of case TELOPT_TSPEED */

	default:
		/* What? */
		break;
	}  /* end of switch */

#if	defined(CRAY2) && defined(UNICOS5)
	/*
	 * Just in case of the likely event that we changed the pty state.
	 */
	rcv_ioctl();
#endif	/* defined(CRAY2) && defined(UNICOS5) */

	netflush();

}  /* end of clientstat */

#if	defined(CRAY2) && defined(UNICOS5)
void
termstat()
{
	needtermstat = 1;
}

void
_termstat()
{
	needtermstat = 0;
	init_termbuf();
	localstat();
	rcv_ioctl();
}
#endif	/* defined(CRAY2) && defined(UNICOS5) */

/*
 * defer_terminit
 *
 * Some things should not be done until after the login process has started
 * and all the pty modes are set to what they are supposed to be.  This
 * function is called when the pty state has been processed for the first time.
 * It calls other functions that do things that were deferred in each module.
 */
void
defer_terminit()
{

	/*
	 * local stuff that got deferred.
	 */
	if (def_tspeed != -1) {
		clientstat(TELOPT_TSPEED, def_tspeed, def_rspeed);
		def_tspeed = def_rspeed = 0;
	}

#ifdef	TIOCSWINSZ
	if (def_col || def_row) {
		struct winsize ws;

		memset((char *)&ws, 0, sizeof(ws));
		ws.ws_col = def_col;
		ws.ws_row = def_row;
		(void) ioctl(pty, TIOCSWINSZ, (char *)&ws);
	}
#endif

	/*
	 * The only other module that currently defers anything.
	 */
	deferslc();

}  /* end of defer_terminit */

/*
 * terminit
 *
 * Returns true if the pty state has been processed yet.
 */
int
terminit()
{
	return(_terminit);

}  /* end of terminit */