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, see <http://www.gnu.org/licenses/>. *
23 ***************************************************************************/
29 #include "telnet_server.h"
30 #include <target/target_request.h>
31 #include <helper/configuration.h>
33 static char *telnet_port;
35 static char *negotiate =
36 "\xFF\xFB\x03" /* IAC WILL Suppress Go Ahead */
37 "\xFF\xFB\x01" /* IAC WILL Echo */
38 "\xFF\xFD\x03" /* IAC DO Suppress Go Ahead */
39 "\xFF\xFE\x01"; /* IAC DON'T Echo */
41 #define CTRL(c) (c - '@')
42 #define TELNET_HISTORY ".openocd_history"
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 void telnet_load_history(struct telnet_connection *t_con)
133 char buffer[TELNET_BUFFER_SIZE];
136 char *history = get_home_dir(TELNET_HISTORY);
138 if (history == NULL) {
139 LOG_INFO("unable to get user home directory, telnet history will be disabled");
143 histfp = fopen(history, "rb");
147 while (fgets(buffer, sizeof(buffer), histfp) != NULL) {
149 char *p = strchr(buffer, '\n');
152 if (buffer[0] && i < TELNET_LINE_HISTORY_SIZE)
153 t_con->history[i++] = strdup(buffer);
156 t_con->next_history = i;
157 t_con->next_history %= TELNET_LINE_HISTORY_SIZE;
158 /* try to set to last entry - 1, that way we skip over any exit/shutdown cmds */
159 t_con->current_history = t_con->next_history > 0 ? i - 1 : 0;
166 static void telnet_save_history(struct telnet_connection *t_con)
172 char *history = get_home_dir(TELNET_HISTORY);
174 if (history == NULL) {
175 LOG_INFO("unable to get user home directory, telnet history will be disabled");
179 histfp = fopen(history, "wb");
183 num = TELNET_LINE_HISTORY_SIZE;
184 i = t_con->current_history + 1;
185 i %= TELNET_LINE_HISTORY_SIZE;
187 while (t_con->history[i] == NULL && num > 0) {
189 i %= TELNET_LINE_HISTORY_SIZE;
194 for (; num > 0; num--) {
195 fprintf(histfp, "%s\n", t_con->history[i]);
197 i %= TELNET_LINE_HISTORY_SIZE;
206 static int telnet_new_connection(struct connection *connection)
208 struct telnet_connection *telnet_connection;
209 struct telnet_service *telnet_service = connection->service->priv;
212 telnet_connection = malloc(sizeof(struct telnet_connection));
214 if (!telnet_connection) {
215 LOG_ERROR("Failed to allocate telnet connection.");
219 connection->priv = telnet_connection;
221 /* initialize telnet connection information */
222 telnet_connection->closed = 0;
223 telnet_connection->line_size = 0;
224 telnet_connection->line_cursor = 0;
225 telnet_connection->option_size = 0;
226 telnet_connection->prompt = strdup("> ");
227 telnet_connection->state = TELNET_STATE_DATA;
229 /* output goes through telnet connection */
230 command_set_output_handler(connection->cmd_ctx, telnet_output, connection);
232 /* negotiate telnet options */
233 telnet_write(connection, negotiate, strlen(negotiate));
235 /* print connection banner */
236 if (telnet_service->banner) {
237 telnet_write(connection, telnet_service->banner, strlen(telnet_service->banner));
238 telnet_write(connection, "\r\n", 2);
241 /* the prompt is always placed at the line beginning */
242 telnet_write(connection, "\r", 1);
243 telnet_prompt(connection);
245 /* initialize history */
246 for (i = 0; i < TELNET_LINE_HISTORY_SIZE; i++)
247 telnet_connection->history[i] = NULL;
248 telnet_connection->next_history = 0;
249 telnet_connection->current_history = 0;
250 telnet_load_history(telnet_connection);
252 log_add_callback(telnet_log_callback, connection);
257 static void telnet_clear_line(struct connection *connection,
258 struct telnet_connection *t_con)
260 /* move to end of line */
261 if (t_con->line_cursor < t_con->line_size)
262 telnet_write(connection,
263 t_con->line + t_con->line_cursor,
264 t_con->line_size - t_con->line_cursor);
266 /* backspace, overwrite with space, backspace */
267 while (t_con->line_size > 0) {
268 telnet_write(connection, "\b \b", 3);
271 t_con->line_cursor = 0;
274 static void telnet_history_go(struct connection *connection, int idx)
276 struct telnet_connection *t_con = connection->priv;
278 if (t_con->history[idx]) {
279 telnet_clear_line(connection, t_con);
280 t_con->line_size = strlen(t_con->history[idx]);
281 t_con->line_cursor = t_con->line_size;
282 memcpy(t_con->line, t_con->history[idx], t_con->line_size);
283 telnet_write(connection, t_con->line, t_con->line_size);
284 t_con->current_history = idx;
286 t_con->state = TELNET_STATE_DATA;
289 static void telnet_history_up(struct connection *connection)
291 struct telnet_connection *t_con = connection->priv;
293 int last_history = (t_con->current_history > 0) ?
294 t_con->current_history - 1 :
295 TELNET_LINE_HISTORY_SIZE-1;
296 telnet_history_go(connection, last_history);
299 static void telnet_history_down(struct connection *connection)
301 struct telnet_connection *t_con = connection->priv;
303 int next_history = (t_con->current_history + 1) % TELNET_LINE_HISTORY_SIZE;
304 telnet_history_go(connection, next_history);
307 static int telnet_input(struct connection *connection)
310 unsigned char buffer[TELNET_BUFFER_SIZE];
311 unsigned char *buf_p;
312 struct telnet_connection *t_con = connection->priv;
313 struct command_context *command_context = connection->cmd_ctx;
315 bytes_read = connection_read(connection, buffer, TELNET_BUFFER_SIZE);
318 return ERROR_SERVER_REMOTE_CLOSED;
319 else if (bytes_read == -1) {
320 LOG_ERROR("error during read: %s", strerror(errno));
321 return ERROR_SERVER_REMOTE_CLOSED;
326 switch (t_con->state) {
327 case TELNET_STATE_DATA:
329 t_con->state = TELNET_STATE_IAC;
331 if (isprint(*buf_p)) { /* printable character */
332 /* watch buffer size leaving one spare character for
333 * string null termination */
334 if (t_con->line_size == TELNET_LINE_MAX_SIZE-1) {
335 /* output audible bell if buffer is full
336 * "\a" does not work, at least on windows */
337 telnet_write(connection, "\x07", 1);
338 } else if (t_con->line_cursor == t_con->line_size) {
339 telnet_write(connection, buf_p, 1);
340 t_con->line[t_con->line_size++] = *buf_p;
341 t_con->line_cursor++;
344 memmove(t_con->line + t_con->line_cursor + 1,
345 t_con->line + t_con->line_cursor,
346 t_con->line_size - t_con->line_cursor);
347 t_con->line[t_con->line_cursor] = *buf_p;
349 telnet_write(connection,
350 t_con->line + t_con->line_cursor,
351 t_con->line_size - t_con->line_cursor);
352 t_con->line_cursor++;
353 for (i = t_con->line_cursor; i < t_con->line_size; i++)
354 telnet_write(connection, "\b", 1);
356 } else { /* non-printable */
357 if (*buf_p == 0x1b) { /* escape */
358 t_con->state = TELNET_STATE_ESCAPE;
359 t_con->last_escape = '\x00';
360 } else if ((*buf_p == 0xd) || (*buf_p == 0xa)) { /* CR/LF */
363 /* skip over combinations with CR/LF and NUL characters */
364 if ((bytes_read > 1) && ((*(buf_p + 1) == 0xa) ||
365 (*(buf_p + 1) == 0xd))) {
369 if ((bytes_read > 1) && (*(buf_p + 1) == 0)) {
373 t_con->line[t_con->line_size] = 0;
375 telnet_write(connection, "\r\n\x00", 3);
377 if (strcmp(t_con->line, "history") == 0) {
379 for (i = 1; i < TELNET_LINE_HISTORY_SIZE; i++) {
380 /* the t_con->next_history line contains empty string
381 * (unless NULL), thus it is not printed */
382 char *history_line = t_con->history[(t_con->
384 TELNET_LINE_HISTORY_SIZE];
386 telnet_write(connection, history_line,
387 strlen(history_line));
388 telnet_write(connection, "\r\n\x00", 3);
391 t_con->line_size = 0;
392 t_con->line_cursor = 0;
396 /* save only non-blank not repeating lines in the history */
397 char *prev_line = t_con->history[(t_con->current_history > 0) ?
398 t_con->current_history - 1 : TELNET_LINE_HISTORY_SIZE-1];
399 if (*t_con->line && (prev_line == NULL ||
400 strcmp(t_con->line, prev_line))) {
401 /* if the history slot is already taken, free it */
402 if (t_con->history[t_con->next_history])
403 free(t_con->history[t_con->next_history]);
405 /* add line to history */
406 t_con->history[t_con->next_history] = strdup(t_con->line);
408 /* wrap history at TELNET_LINE_HISTORY_SIZE */
409 t_con->next_history = (t_con->next_history + 1) %
410 TELNET_LINE_HISTORY_SIZE;
412 /* current history line starts at the new entry */
413 t_con->current_history =
416 if (t_con->history[t_con->current_history])
417 free(t_con->history[t_con->current_history]);
418 t_con->history[t_con->current_history] = strdup("");
421 t_con->line_size = 0;
423 /* to suppress prompt in log callback during command execution */
424 t_con->line_cursor = -1;
426 if (strcmp(t_con->line, "shutdown") == 0)
427 telnet_save_history(t_con);
429 retval = command_run_line(command_context, t_con->line);
431 t_con->line_cursor = 0;
433 if (retval == ERROR_COMMAND_CLOSE_CONNECTION)
434 return ERROR_SERVER_REMOTE_CLOSED;
436 /* the prompt is always * placed at the line beginning */
437 telnet_write(connection, "\r", 1);
439 retval = telnet_prompt(connection);
440 if (retval == ERROR_SERVER_REMOTE_CLOSED)
441 return ERROR_SERVER_REMOTE_CLOSED;
443 } else if ((*buf_p == 0x7f) || (*buf_p == 0x8)) { /* delete character */
444 if (t_con->line_cursor > 0) {
445 if (t_con->line_cursor != t_con->line_size) {
447 telnet_write(connection, "\b", 1);
448 t_con->line_cursor--;
450 memmove(t_con->line + t_con->line_cursor,
451 t_con->line + t_con->line_cursor + 1,
455 telnet_write(connection,
456 t_con->line + t_con->line_cursor,
459 telnet_write(connection, " \b", 2);
460 for (i = t_con->line_cursor; i < t_con->line_size; i++)
461 telnet_write(connection, "\b", 1);
464 t_con->line_cursor--;
465 /* back space: move the 'printer' head one char
466 * back, overwrite with space, move back again */
467 telnet_write(connection, "\b \b", 3);
470 } else if (*buf_p == 0x15) /* clear line */
471 telnet_clear_line(connection, t_con);
472 else if (*buf_p == CTRL('B')) { /* cursor left */
473 if (t_con->line_cursor > 0) {
474 telnet_write(connection, "\b", 1);
475 t_con->line_cursor--;
477 t_con->state = TELNET_STATE_DATA;
478 } else if (*buf_p == CTRL('F')) { /* cursor right */
479 if (t_con->line_cursor < t_con->line_size)
480 telnet_write(connection, t_con->line + t_con->line_cursor++, 1);
481 t_con->state = TELNET_STATE_DATA;
482 } else if (*buf_p == CTRL('P')) /* cursor up */
483 telnet_history_up(connection);
484 else if (*buf_p == CTRL('N')) /* cursor down */
485 telnet_history_down(connection);
487 LOG_DEBUG("unhandled nonprintable: %2.2x", *buf_p);
491 case TELNET_STATE_IAC:
494 t_con->state = TELNET_STATE_DONT;
497 t_con->state = TELNET_STATE_DO;
500 t_con->state = TELNET_STATE_WONT;
503 t_con->state = TELNET_STATE_WILL;
507 case TELNET_STATE_SB:
509 case TELNET_STATE_SE:
511 case TELNET_STATE_WILL:
512 case TELNET_STATE_WONT:
513 case TELNET_STATE_DO:
514 case TELNET_STATE_DONT:
515 t_con->state = TELNET_STATE_DATA;
517 case TELNET_STATE_ESCAPE:
518 if (t_con->last_escape == '[') {
519 if (*buf_p == 'D') { /* cursor left */
520 if (t_con->line_cursor > 0) {
521 telnet_write(connection, "\b", 1);
522 t_con->line_cursor--;
524 t_con->state = TELNET_STATE_DATA;
525 } else if (*buf_p == 'C') { /* cursor right */
526 if (t_con->line_cursor < t_con->line_size)
527 telnet_write(connection,
528 t_con->line + t_con->line_cursor++, 1);
529 t_con->state = TELNET_STATE_DATA;
530 } else if (*buf_p == 'A') { /* cursor up */
531 telnet_history_up(connection);
532 } else if (*buf_p == 'B') { /* cursor down */
533 telnet_history_down(connection);
534 } else if (*buf_p == '3')
535 t_con->last_escape = *buf_p;
537 t_con->state = TELNET_STATE_DATA;
538 } else if (t_con->last_escape == '3') {
539 /* Remove character */
541 if (t_con->line_cursor < t_con->line_size) {
544 /* remove char from line buffer */
545 memmove(t_con->line + t_con->line_cursor,
546 t_con->line + t_con->line_cursor + 1,
547 t_con->line_size - t_con->line_cursor);
549 /* print remainder of buffer */
550 telnet_write(connection, t_con->line + t_con->line_cursor,
551 t_con->line_size - t_con->line_cursor);
552 /* overwrite last char with whitespace */
553 telnet_write(connection, " \b", 2);
555 /* move back to cursor position*/
556 for (i = t_con->line_cursor; i < t_con->line_size; i++)
557 telnet_write(connection, "\b", 1);
560 t_con->state = TELNET_STATE_DATA;
562 t_con->state = TELNET_STATE_DATA;
563 } else if (t_con->last_escape == '\x00') {
565 t_con->last_escape = *buf_p;
567 t_con->state = TELNET_STATE_DATA;
569 LOG_ERROR("BUG: unexpected value in t_con->last_escape");
570 t_con->state = TELNET_STATE_DATA;
575 LOG_ERROR("unknown telnet state");
586 static int telnet_connection_closed(struct connection *connection)
588 struct telnet_connection *t_con = connection->priv;
591 log_remove_callback(telnet_log_callback, connection);
595 t_con->prompt = NULL;
598 /* save telnet history */
599 telnet_save_history(t_con);
601 for (i = 0; i < TELNET_LINE_HISTORY_SIZE; i++) {
602 if (t_con->history[i]) {
603 free(t_con->history[i]);
604 t_con->history[i] = NULL;
608 /* if this connection registered a debug-message receiver delete it */
609 delete_debug_msg_receiver(connection->cmd_ctx, NULL);
611 if (connection->priv) {
612 free(connection->priv);
613 connection->priv = NULL;
615 LOG_ERROR("BUG: connection->priv == NULL");
620 int telnet_init(char *banner)
622 if (strcmp(telnet_port, "disabled") == 0) {
623 LOG_INFO("telnet server disabled");
627 struct telnet_service *telnet_service =
628 malloc(sizeof(struct telnet_service));
630 if (!telnet_service) {
631 LOG_ERROR("Failed to allocate telnet service.");
635 telnet_service->banner = banner;
637 int ret = add_service("telnet", telnet_port, CONNECTION_LIMIT_UNLIMITED,
638 telnet_new_connection, telnet_input, telnet_connection_closed,
641 if (ret != ERROR_OK) {
642 free(telnet_service);
649 /* daemon configuration command telnet_port */
650 COMMAND_HANDLER(handle_telnet_port_command)
652 return CALL_COMMAND_HANDLER(server_pipe_command, &telnet_port);
655 COMMAND_HANDLER(handle_exit_command)
657 return ERROR_COMMAND_CLOSE_CONNECTION;
660 static const struct command_registration telnet_command_handlers[] = {
663 .handler = handle_exit_command,
664 .mode = COMMAND_EXEC,
666 .help = "exit telnet session",
669 .name = "telnet_port",
670 .handler = handle_telnet_port_command,
672 .help = "Specify port on which to listen "
673 "for incoming telnet connections. "
674 "Read help on 'gdb_port'.",
675 .usage = "[port_num]",
677 COMMAND_REGISTRATION_DONE
680 int telnet_register_commands(struct command_context *cmd_ctx)
682 telnet_port = strdup("4444");
683 return register_commands(cmd_ctx, NULL, telnet_command_handlers);