telnet/telnetd/termstat.c

63  * This function handles all management of linemode.
68  * external processing, then we can use linemode.  Further, if we
69  * can use real linemode, then we can look at the edit control bits
73  * current and desired linemode state.
75  * 	command line.  It means to have linemode on as much as
79  *	handle real linemode, or if use of kludgeomatic linemode
81  *		REAL_LINEMODE : use linemode option
82  *		NO_KLUDGE : don't initiate kludge linemode.
83  *		KLUDGE_LINEMODE : use kludge linemode
84  *		NO_LINEMODE : client is ignorant of linemode
86  *	linemode, uselinemode : linemode is true if linemode
88  *	to be in.  If another function wishes to turn linemode
91  *	editmode, useeditmode : like linemode/uselinemode, but
96  *	linemode:
97  *		In real linemode, this corresponds to whether the pty
99  *		In kludge linemode, this more closely corresponds to the
106  * The following heuristics are applied to determine linemode
109  *	   to negotiate the linemode option.  If this succeeds
110  *	   then lmodetype is set to REAL_LINEMODE and all linemode
111  *	   processing occurs in the context of the linemode option.
112  *	2) If the attempt to negotiate the linemode option failed,
113  *	   and the "-k" (don't initiate kludge linemode) isn't set,
114  *	   then we try to use kludge linemode.  We test for this
117  *	   understands kludge linemode (ech!) and the
119  *	3) Otherwise, linemode is not supported at all and
123  *	   state of linemode support in the client, we move to that
124  *	   linemode support.
126  * A short explanation of kludge linemode is in order here.
127  *	1) The heuristic to determine support for kludge linemode
129  *	   that supports timing marks also supports kludge linemode.
131  *	2) Further negotiation of linemode is done by changing the
133  *	   then linemode is off, if server won't SGA, then linemode
147 	 * Check linemode on/off state
153 	 * force linemode back on.
155 	if (alwayslinemode && linemode && !uselinemode) {
165 		 * to use linemode.  As this confuses some telnet clients
166 		 * that don't support linemode, and doesn't gain us
167 		 * anything, we don't do it unless we're doing linemode.
210 	 * linemode is going to be.
213 	 * will echo if in character mode, but in linemode the
238 	 * If linemode is being turned off, send appropriate
241 	 if (!uselinemode && linemode) {
251 		linemode = uselinemode;
257 	 * If using real linemode check edit modes for possible later use.
258 	 * If we are in kludge linemode, do the SGA negotiation.
281 	 * Negotiate linemode on if pty state has changed to turn it on.
284 	if (uselinemode && !linemode) {
299 		linemode = uselinemode;
306 	 * real linemode.
312 	if (linemode && his_state_is_will(TELOPT_LINEMODE)) {
385  * Process linemode related requests from the client.
386  * Client can request a change to only one of linemode, editmode or slc's
387  * at a time, and if using kludge linemode, then only linemode may be
410 		if (uselinemode != linemode) {
413 			 * If using kludge linemode, make sure that
415 			 * We can not turn off linemode if alwayslinemode
427 			if (uselinemode == linemode)
431 			 * If using real linemode and linemode is being
457 			linemode = uselinemode;
459 			if (!linemode)