1 /***************************************************************************
2 * Copyright (C) 2005 by Dominic Rath *
3 * Dominic.Rath@gmx.de *
5 * Copyright (C) 2007-2010 Øyvind Harboe *
6 * oyvind.harboe@zylin.com *
8 * Copyright (C) 2008 by Spencer Oliver *
9 * spen@spen-soft.co.uk *
11 * This program is free software; you can redistribute it and/or modify *
12 * it under the terms of the GNU General Public License as published by *
13 * the Free Software Foundation; either version 2 of the License, or *
14 * (at your option) any later version. *
16 * This program is distributed in the hope that it will be useful, *
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of *
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
19 * GNU General Public License for more details. *
21 * You should have received a copy of the GNU General Public License *
22 * along with this program; if not, write to the *
23 * Free Software Foundation, Inc., *
24 * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. *
25 ***************************************************************************/
31 #include "telnet_server.h"
32 #include <target/target_request.h>
34 static const char *telnet_port
;
36 static char *negotiate
=
37 "\xFF\xFB\x03" /* IAC WILL Suppress Go Ahead */
38 "\xFF\xFB\x01" /* IAC WILL Echo */
39 "\xFF\xFD\x03" /* IAC DO Suppress Go Ahead */
40 "\xFF\xFE\x01"; /* IAC DON'T Echo */
42 #define CTRL(c) (c - '@')
44 /* The only way we can detect that the socket is closed is the first time
45 * we write to it, we will fail. Subsequent write operations will
48 static int telnet_write(struct connection
*connection
, const void *data
,
51 struct telnet_connection
*t_con
= connection
->priv
;
53 return ERROR_SERVER_REMOTE_CLOSED
;
55 if (connection_write(connection
, data
, len
) == len
)
58 return ERROR_SERVER_REMOTE_CLOSED
;
61 static int telnet_prompt(struct connection
*connection
)
63 struct telnet_connection
*t_con
= connection
->priv
;
65 return telnet_write(connection
, t_con
->prompt
, strlen(t_con
->prompt
));
68 static int telnet_outputline(struct connection
*connection
, const char *line
)
72 /* process lines in buffer */
74 char *line_end
= strchr(line
, '\n');
81 telnet_write(connection
, line
, len
);
83 telnet_write(connection
, "\r\n", 2);
92 static int telnet_output(struct command_context
*cmd_ctx
, const char *line
)
94 struct connection
*connection
= cmd_ctx
->output_handler_priv
;
96 return telnet_outputline(connection
, line
);
99 static void telnet_log_callback(void *priv
, const char *file
, unsigned line
,
100 const char *function
, const char *string
)
102 struct connection
*connection
= priv
;
103 struct telnet_connection
*t_con
= connection
->priv
;
106 /* if there is no prompt, simply output the message */
107 if (t_con
->line_cursor
< 0) {
108 telnet_outputline(connection
, string
);
112 /* clear the command line */
113 for (i
= strlen(t_con
->prompt
) + t_con
->line_size
; i
> 0; i
-= 16)
114 telnet_write(connection
, "\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b", i
> 16 ? 16 : i
);
115 for (i
= strlen(t_con
->prompt
) + t_con
->line_size
; i
> 0; i
-= 16)
116 telnet_write(connection
, " ", i
> 16 ? 16 : i
);
117 for (i
= strlen(t_con
->prompt
) + t_con
->line_size
; i
> 0; i
-= 16)
118 telnet_write(connection
, "\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b", i
> 16 ? 16 : i
);
120 /* output the message */
121 telnet_outputline(connection
, string
);
123 /* put the command line to its previous state */
124 telnet_prompt(connection
);
125 telnet_write(connection
, t_con
->line
, t_con
->line_size
);
126 for (i
= t_con
->line_size
; i
> t_con
->line_cursor
; i
--)
127 telnet_write(connection
, "\b", 1);
130 static int telnet_new_connection(struct connection
*connection
)
132 struct telnet_connection
*telnet_connection
= malloc(sizeof(struct telnet_connection
));
133 struct telnet_service
*telnet_service
= connection
->service
->priv
;
136 connection
->priv
= telnet_connection
;
138 /* initialize telnet connection information */
139 telnet_connection
->closed
= 0;
140 telnet_connection
->line_size
= 0;
141 telnet_connection
->line_cursor
= 0;
142 telnet_connection
->option_size
= 0;
143 telnet_connection
->prompt
= strdup("> ");
144 telnet_connection
->state
= TELNET_STATE_DATA
;
146 /* output goes through telnet connection */
147 command_set_output_handler(connection
->cmd_ctx
, telnet_output
, connection
);
149 /* negotiate telnet options */
150 telnet_write(connection
, negotiate
, strlen(negotiate
));
152 /* print connection banner */
153 if (telnet_service
->banner
) {
154 telnet_write(connection
, telnet_service
->banner
, strlen(telnet_service
->banner
));
155 telnet_write(connection
, "\r\n", 2);
158 /* the prompt is always placed at the line beginning */
159 telnet_write(connection
, "\r", 1);
160 telnet_prompt(connection
);
162 /* initialize history */
163 for (i
= 0; i
< TELNET_LINE_HISTORY_SIZE
; i
++)
164 telnet_connection
->history
[i
] = NULL
;
165 telnet_connection
->next_history
= 0;
166 telnet_connection
->current_history
= 0;
168 log_add_callback(telnet_log_callback
, connection
);
173 static void telnet_clear_line(struct connection
*connection
,
174 struct telnet_connection
*t_con
)
176 /* move to end of line */
177 if (t_con
->line_cursor
< t_con
->line_size
)
178 telnet_write(connection
,
179 t_con
->line
+ t_con
->line_cursor
,
180 t_con
->line_size
- t_con
->line_cursor
);
182 /* backspace, overwrite with space, backspace */
183 while (t_con
->line_size
> 0) {
184 telnet_write(connection
, "\b \b", 3);
187 t_con
->line_cursor
= 0;
190 static int telnet_input(struct connection
*connection
)
193 unsigned char buffer
[TELNET_BUFFER_SIZE
];
194 unsigned char *buf_p
;
195 struct telnet_connection
*t_con
= connection
->priv
;
196 struct command_context
*command_context
= connection
->cmd_ctx
;
198 bytes_read
= connection_read(connection
, buffer
, TELNET_BUFFER_SIZE
);
201 return ERROR_SERVER_REMOTE_CLOSED
;
202 else if (bytes_read
== -1) {
203 LOG_ERROR("error during read: %s", strerror(errno
));
204 return ERROR_SERVER_REMOTE_CLOSED
;
209 switch (t_con
->state
) {
210 case TELNET_STATE_DATA
:
212 t_con
->state
= TELNET_STATE_IAC
;
214 if (isprint(*buf_p
)) { /* printable character */
215 /* watch buffer size leaving one spare character for
216 * string null termination */
217 if (t_con
->line_size
== TELNET_LINE_MAX_SIZE
-1) {
218 /* output audible bell if buffer is full
219 * "\a" does not work, at least on windows */
220 telnet_write(connection
, "\x07", 1);
221 } else if (t_con
->line_cursor
== t_con
->line_size
) {
222 telnet_write(connection
, buf_p
, 1);
223 t_con
->line
[t_con
->line_size
++] = *buf_p
;
224 t_con
->line_cursor
++;
227 memmove(t_con
->line
+ t_con
->line_cursor
+ 1,
228 t_con
->line
+ t_con
->line_cursor
,
229 t_con
->line_size
- t_con
->line_cursor
);
230 t_con
->line
[t_con
->line_cursor
] = *buf_p
;
232 telnet_write(connection
,
233 t_con
->line
+ t_con
->line_cursor
,
234 t_con
->line_size
- t_con
->line_cursor
);
235 t_con
->line_cursor
++;
236 for (i
= t_con
->line_cursor
; i
< t_con
->line_size
; i
++)
237 telnet_write(connection
, "\b", 1);
239 } else { /* non-printable */
240 if (*buf_p
== 0x1b) { /* escape */
241 t_con
->state
= TELNET_STATE_ESCAPE
;
242 t_con
->last_escape
= '\x00';
243 } else if ((*buf_p
== 0xd) || (*buf_p
== 0xa)) { /* CR/LF */
246 /* skip over combinations with CR/LF and NUL characters */
247 if ((bytes_read
> 1) && ((*(buf_p
+ 1) == 0xa) ||
248 (*(buf_p
+ 1) == 0xd))) {
252 if ((bytes_read
> 1) && (*(buf_p
+ 1) == 0)) {
256 t_con
->line
[t_con
->line_size
] = 0;
258 telnet_write(connection
, "\r\n\x00", 3);
260 if (strcmp(t_con
->line
, "history") == 0) {
262 for (i
= 1; i
< TELNET_LINE_HISTORY_SIZE
; i
++) {
263 /* the t_con->next_history line contains empty string
264 * (unless NULL), thus it is not printed */
265 char *history_line
= t_con
->history
[(t_con
->
267 TELNET_LINE_HISTORY_SIZE
];
269 telnet_write(connection
, history_line
,
270 strlen(history_line
));
271 telnet_write(connection
, "\r\n\x00", 3);
274 t_con
->line_size
= 0;
275 t_con
->line_cursor
= 0;
279 /* save only non-blank not repeating lines in the history */
280 char *prev_line
= t_con
->history
[(t_con
->current_history
> 0) ?
281 t_con
->current_history
- 1 : TELNET_LINE_HISTORY_SIZE
-1];
282 if (*t_con
->line
&& (prev_line
== NULL
||
283 strcmp(t_con
->line
, prev_line
))) {
284 /* if the history slot is already taken, free it */
285 if (t_con
->history
[t_con
->next_history
])
286 free(t_con
->history
[t_con
->next_history
]);
288 /* add line to history */
289 t_con
->history
[t_con
->next_history
] = strdup(t_con
->line
);
291 /* wrap history at TELNET_LINE_HISTORY_SIZE */
292 t_con
->next_history
= (t_con
->next_history
+ 1) %
293 TELNET_LINE_HISTORY_SIZE
;
295 /* current history line starts at the new entry */
296 t_con
->current_history
=
299 if (t_con
->history
[t_con
->current_history
])
300 free(t_con
->history
[t_con
->current_history
]);
301 t_con
->history
[t_con
->current_history
] = strdup("");
304 t_con
->line_size
= 0;
306 /* to suppress prompt in log callback during command execution */
307 t_con
->line_cursor
= -1;
309 retval
= command_run_line(command_context
, t_con
->line
);
311 t_con
->line_cursor
= 0;
313 if (retval
== ERROR_COMMAND_CLOSE_CONNECTION
)
314 return ERROR_SERVER_REMOTE_CLOSED
;
316 /* the prompt is always * placed at the line beginning */
317 telnet_write(connection
, "\r", 1);
319 retval
= telnet_prompt(connection
);
320 if (retval
== ERROR_SERVER_REMOTE_CLOSED
)
321 return ERROR_SERVER_REMOTE_CLOSED
;
323 } else if ((*buf_p
== 0x7f) || (*buf_p
== 0x8)) { /* delete character */
324 if (t_con
->line_cursor
> 0) {
325 if (t_con
->line_cursor
!= t_con
->line_size
) {
327 telnet_write(connection
, "\b", 1);
328 t_con
->line_cursor
--;
330 memmove(t_con
->line
+ t_con
->line_cursor
,
331 t_con
->line
+ t_con
->line_cursor
+ 1,
335 telnet_write(connection
,
336 t_con
->line
+ t_con
->line_cursor
,
339 telnet_write(connection
, " \b", 2);
340 for (i
= t_con
->line_cursor
; i
< t_con
->line_size
; i
++)
341 telnet_write(connection
, "\b", 1);
344 t_con
->line_cursor
--;
345 /* back space: move the 'printer' head one char
346 * back, overwrite with space, move back again */
347 telnet_write(connection
, "\b \b", 3);
350 } else if (*buf_p
== 0x15) /* clear line */
351 telnet_clear_line(connection
, t_con
);
352 else if (*buf_p
== CTRL('B')) { /* cursor left */
353 if (t_con
->line_cursor
> 0) {
354 telnet_write(connection
, "\b", 1);
355 t_con
->line_cursor
--;
357 t_con
->state
= TELNET_STATE_DATA
;
358 } else if (*buf_p
== CTRL('F')) { /* cursor right */
359 if (t_con
->line_cursor
< t_con
->line_size
)
360 telnet_write(connection
, t_con
->line
+ t_con
->line_cursor
++, 1);
361 t_con
->state
= TELNET_STATE_DATA
;
363 LOG_DEBUG("unhandled nonprintable: %2.2x", *buf_p
);
367 case TELNET_STATE_IAC
:
370 t_con
->state
= TELNET_STATE_DONT
;
373 t_con
->state
= TELNET_STATE_DO
;
376 t_con
->state
= TELNET_STATE_WONT
;
379 t_con
->state
= TELNET_STATE_WILL
;
383 case TELNET_STATE_SB
:
385 case TELNET_STATE_SE
:
387 case TELNET_STATE_WILL
:
388 case TELNET_STATE_WONT
:
389 case TELNET_STATE_DO
:
390 case TELNET_STATE_DONT
:
391 t_con
->state
= TELNET_STATE_DATA
;
393 case TELNET_STATE_ESCAPE
:
394 if (t_con
->last_escape
== '[') {
395 if (*buf_p
== 'D') { /* cursor left */
396 if (t_con
->line_cursor
> 0) {
397 telnet_write(connection
, "\b", 1);
398 t_con
->line_cursor
--;
400 t_con
->state
= TELNET_STATE_DATA
;
401 } else if (*buf_p
== 'C') { /* cursor right */
402 if (t_con
->line_cursor
< t_con
->line_size
)
403 telnet_write(connection
,
404 t_con
->line
+ t_con
->line_cursor
++, 1);
405 t_con
->state
= TELNET_STATE_DATA
;
406 } else if (*buf_p
== 'A') { /* cursor up */
407 int last_history
= (t_con
->current_history
> 0) ?
408 t_con
->current_history
- 1 : TELNET_LINE_HISTORY_SIZE
-1;
409 if (t_con
->history
[last_history
]) {
410 telnet_clear_line(connection
, t_con
);
411 t_con
->line_size
= strlen(t_con
->history
[last_history
]);
412 t_con
->line_cursor
= t_con
->line_size
;
413 memcpy(t_con
->line
, t_con
->history
[last_history
], t_con
->line_size
);
414 telnet_write(connection
, t_con
->line
, t_con
->line_size
);
415 t_con
->current_history
= last_history
;
417 t_con
->state
= TELNET_STATE_DATA
;
418 } else if (*buf_p
== 'B') { /* cursor down */
419 int next_history
= (t_con
->current_history
+ 1) % TELNET_LINE_HISTORY_SIZE
;
420 if (t_con
->history
[next_history
]) {
421 telnet_clear_line(connection
, t_con
);
422 t_con
->line_size
= strlen(t_con
->history
[next_history
]);
423 t_con
->line_cursor
= t_con
->line_size
;
424 memcpy(t_con
->line
, t_con
->history
[next_history
], t_con
->line_size
);
425 telnet_write(connection
, t_con
->line
, t_con
->line_size
);
426 t_con
->current_history
= next_history
;
428 t_con
->state
= TELNET_STATE_DATA
;
429 } else if (*buf_p
== '3')
430 t_con
->last_escape
= *buf_p
;
432 t_con
->state
= TELNET_STATE_DATA
;
433 } else if (t_con
->last_escape
== '3') {
434 /* Remove character */
436 if (t_con
->line_cursor
< t_con
->line_size
) {
439 /* remove char from line buffer */
440 memmove(t_con
->line
+ t_con
->line_cursor
,
441 t_con
->line
+ t_con
->line_cursor
+ 1,
442 t_con
->line_size
- t_con
->line_cursor
);
444 /* print remainder of buffer */
445 telnet_write(connection
, t_con
->line
+ t_con
->line_cursor
,
446 t_con
->line_size
- t_con
->line_cursor
);
447 /* overwrite last char with whitespace */
448 telnet_write(connection
, " \b", 2);
450 /* move back to cursor position*/
451 for (i
= t_con
->line_cursor
; i
< t_con
->line_size
; i
++)
452 telnet_write(connection
, "\b", 1);
455 t_con
->state
= TELNET_STATE_DATA
;
457 t_con
->state
= TELNET_STATE_DATA
;
458 } else if (t_con
->last_escape
== '\x00') {
460 t_con
->last_escape
= *buf_p
;
462 t_con
->state
= TELNET_STATE_DATA
;
464 LOG_ERROR("BUG: unexpected value in t_con->last_escape");
465 t_con
->state
= TELNET_STATE_DATA
;
470 LOG_ERROR("unknown telnet state");
481 static int telnet_connection_closed(struct connection
*connection
)
483 struct telnet_connection
*t_con
= connection
->priv
;
486 log_remove_callback(telnet_log_callback
, connection
);
490 t_con
->prompt
= NULL
;
493 for (i
= 0; i
< TELNET_LINE_HISTORY_SIZE
; i
++) {
494 if (t_con
->history
[i
]) {
495 free(t_con
->history
[i
]);
496 t_con
->history
[i
] = NULL
;
500 /* if this connection registered a debug-message receiver delete it */
501 delete_debug_msg_receiver(connection
->cmd_ctx
, NULL
);
503 if (connection
->priv
) {
504 free(connection
->priv
);
505 connection
->priv
= NULL
;
507 LOG_ERROR("BUG: connection->priv == NULL");
512 int telnet_init(char *banner
)
514 if (strcmp(telnet_port
, "disabled") == 0) {
515 LOG_INFO("telnet server disabled");
519 struct telnet_service
*telnet_service
= malloc(sizeof(struct telnet_service
));
521 telnet_service
->banner
= banner
;
523 return add_service("telnet",
526 telnet_new_connection
,
528 telnet_connection_closed
,
532 /* daemon configuration command telnet_port */
533 COMMAND_HANDLER(handle_telnet_port_command
)
535 return CALL_COMMAND_HANDLER(server_pipe_command
, &telnet_port
);
538 COMMAND_HANDLER(handle_exit_command
)
540 return ERROR_COMMAND_CLOSE_CONNECTION
;
543 static const struct command_registration telnet_command_handlers
[] = {
546 .handler
= handle_exit_command
,
547 .mode
= COMMAND_EXEC
,
549 .help
= "exit telnet session",
552 .name
= "telnet_port",
553 .handler
= handle_telnet_port_command
,
555 .help
= "Specify port on which to listen "
556 "for incoming telnet connections. "
557 "Read help on 'gdb_port'.",
558 .usage
= "[port_num]",
560 COMMAND_REGISTRATION_DONE
563 int telnet_register_commands(struct command_context
*cmd_ctx
)
565 telnet_port
= strdup("4444");
566 return register_commands(cmd_ctx
, NULL
, telnet_command_handlers
);