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;
107 /* If the prompt is not visible, simply output the message. */
108 if (!t_con->prompt_visible) {
109 telnet_outputline(connection, string);
113 /* Clear the command line. */
114 tmp = strlen(t_con->prompt) + t_con->line_size;
116 for (i = 0; i < tmp; i += 16)
117 telnet_write(connection, "\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b",
120 for (i = 0; i < tmp; i += 16)
121 telnet_write(connection, " ", MIN(tmp - i, 16));
123 for (i = 0; i < tmp; i += 16)
124 telnet_write(connection, "\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b",
127 telnet_outputline(connection, string);
129 /* Put the command line to its previous state. */
130 telnet_prompt(connection);
131 telnet_write(connection, t_con->line, t_con->line_size);
133 for (i = t_con->line_cursor; i < t_con->line_size; i++)
134 telnet_write(connection, "\b", 1);
137 static void telnet_load_history(struct telnet_connection *t_con)
140 char buffer[TELNET_BUFFER_SIZE];
143 char *history = get_home_dir(TELNET_HISTORY);
145 if (history == NULL) {
146 LOG_INFO("unable to get user home directory, telnet history will be disabled");
150 histfp = fopen(history, "rb");
154 while (fgets(buffer, sizeof(buffer), histfp) != NULL) {
156 char *p = strchr(buffer, '\n');
159 if (buffer[0] && i < TELNET_LINE_HISTORY_SIZE)
160 t_con->history[i++] = strdup(buffer);
163 t_con->next_history = i;
164 t_con->next_history %= TELNET_LINE_HISTORY_SIZE;
165 /* try to set to last entry - 1, that way we skip over any exit/shutdown cmds */
166 t_con->current_history = t_con->next_history > 0 ? i - 1 : 0;
173 static void telnet_save_history(struct telnet_connection *t_con)
179 char *history = get_home_dir(TELNET_HISTORY);
181 if (history == NULL) {
182 LOG_INFO("unable to get user home directory, telnet history will be disabled");
186 histfp = fopen(history, "wb");
190 num = TELNET_LINE_HISTORY_SIZE;
191 i = t_con->current_history + 1;
192 i %= TELNET_LINE_HISTORY_SIZE;
194 while (t_con->history[i] == NULL && num > 0) {
196 i %= TELNET_LINE_HISTORY_SIZE;
201 for (; num > 0; num--) {
202 fprintf(histfp, "%s\n", t_con->history[i]);
204 i %= TELNET_LINE_HISTORY_SIZE;
213 static int telnet_new_connection(struct connection *connection)
215 struct telnet_connection *telnet_connection;
216 struct telnet_service *telnet_service = connection->service->priv;
219 telnet_connection = malloc(sizeof(struct telnet_connection));
221 if (!telnet_connection) {
222 LOG_ERROR("Failed to allocate telnet connection.");
226 connection->priv = telnet_connection;
228 /* initialize telnet connection information */
229 telnet_connection->closed = false;
230 telnet_connection->line_size = 0;
231 telnet_connection->line_cursor = 0;
232 telnet_connection->prompt = strdup("> ");
233 telnet_connection->prompt_visible = true;
234 telnet_connection->state = TELNET_STATE_DATA;
236 /* output goes through telnet connection */
237 command_set_output_handler(connection->cmd_ctx, telnet_output, connection);
239 /* negotiate telnet options */
240 telnet_write(connection, negotiate, strlen(negotiate));
242 /* print connection banner */
243 if (telnet_service->banner) {
244 telnet_write(connection, telnet_service->banner, strlen(telnet_service->banner));
245 telnet_write(connection, "\r\n", 2);
248 /* the prompt is always placed at the line beginning */
249 telnet_write(connection, "\r", 1);
250 telnet_prompt(connection);
252 /* initialize history */
253 for (i = 0; i < TELNET_LINE_HISTORY_SIZE; i++)
254 telnet_connection->history[i] = NULL;
255 telnet_connection->next_history = 0;
256 telnet_connection->current_history = 0;
257 telnet_load_history(telnet_connection);
259 log_add_callback(telnet_log_callback, connection);
264 static void telnet_clear_line(struct connection *connection,
265 struct telnet_connection *t_con)
267 /* move to end of line */
268 if (t_con->line_cursor < t_con->line_size)
269 telnet_write(connection,
270 t_con->line + t_con->line_cursor,
271 t_con->line_size - t_con->line_cursor);
273 /* backspace, overwrite with space, backspace */
274 while (t_con->line_size > 0) {
275 telnet_write(connection, "\b \b", 3);
278 t_con->line_cursor = 0;
281 static void telnet_history_go(struct connection *connection, int idx)
283 struct telnet_connection *t_con = connection->priv;
285 if (t_con->history[idx]) {
286 telnet_clear_line(connection, t_con);
287 t_con->line_size = strlen(t_con->history[idx]);
288 t_con->line_cursor = t_con->line_size;
289 memcpy(t_con->line, t_con->history[idx], t_con->line_size);
290 telnet_write(connection, t_con->line, t_con->line_size);
291 t_con->current_history = idx;
293 t_con->state = TELNET_STATE_DATA;
296 static void telnet_history_up(struct connection *connection)
298 struct telnet_connection *t_con = connection->priv;
300 size_t last_history = (t_con->current_history > 0) ?
301 t_con->current_history - 1 :
302 TELNET_LINE_HISTORY_SIZE-1;
303 telnet_history_go(connection, last_history);
306 static void telnet_history_down(struct connection *connection)
308 struct telnet_connection *t_con = connection->priv;
311 next_history = (t_con->current_history + 1) % TELNET_LINE_HISTORY_SIZE;
312 telnet_history_go(connection, next_history);
315 static int telnet_history_print(struct connection *connection)
317 struct telnet_connection *tc;
319 tc = connection->priv;
321 for (size_t i = 1; i < TELNET_LINE_HISTORY_SIZE; i++) {
325 * The tc->next_history line contains empty string (unless NULL), thus
328 line = tc->history[(tc->next_history + i) % TELNET_LINE_HISTORY_SIZE];
331 telnet_write(connection, line, strlen(line));
332 telnet_write(connection, "\r\n\x00", 3);
339 /* The prompt is always placed at the line beginning. */
340 telnet_write(connection, "\r", 1);
342 return telnet_prompt(connection);
345 static void telnet_move_cursor(struct connection *connection, size_t pos)
347 struct telnet_connection *tc;
350 tc = connection->priv;
352 if (pos < tc->line_cursor) {
353 tmp = tc->line_cursor - pos;
355 for (size_t i = 0; i < tmp; i += 16)
356 telnet_write(connection, "\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b",
359 tmp = pos - tc->line_cursor;
361 for (size_t i = 0; i < tmp; i += 16)
362 telnet_write(connection, tc->line + tc->line_cursor + i,
366 tc->line_cursor = pos;
369 static int telnet_input(struct connection *connection)
372 unsigned char buffer[TELNET_BUFFER_SIZE];
373 unsigned char *buf_p;
374 struct telnet_connection *t_con = connection->priv;
375 struct command_context *command_context = connection->cmd_ctx;
377 bytes_read = connection_read(connection, buffer, TELNET_BUFFER_SIZE);
380 return ERROR_SERVER_REMOTE_CLOSED;
381 else if (bytes_read == -1) {
382 LOG_ERROR("error during read: %s", strerror(errno));
383 return ERROR_SERVER_REMOTE_CLOSED;
388 switch (t_con->state) {
389 case TELNET_STATE_DATA:
391 t_con->state = TELNET_STATE_IAC;
393 if (isprint(*buf_p)) { /* printable character */
394 /* watch buffer size leaving one spare character for
395 * string null termination */
396 if (t_con->line_size == TELNET_LINE_MAX_SIZE-1) {
397 /* output audible bell if buffer is full
398 * "\a" does not work, at least on windows */
399 telnet_write(connection, "\x07", 1);
400 } else if (t_con->line_cursor == t_con->line_size) {
401 telnet_write(connection, buf_p, 1);
402 t_con->line[t_con->line_size++] = *buf_p;
403 t_con->line_cursor++;
406 memmove(t_con->line + t_con->line_cursor + 1,
407 t_con->line + t_con->line_cursor,
408 t_con->line_size - t_con->line_cursor);
409 t_con->line[t_con->line_cursor] = *buf_p;
411 telnet_write(connection,
412 t_con->line + t_con->line_cursor,
413 t_con->line_size - t_con->line_cursor);
414 t_con->line_cursor++;
415 for (i = t_con->line_cursor; i < t_con->line_size; i++)
416 telnet_write(connection, "\b", 1);
418 } else { /* non-printable */
419 if (*buf_p == 0x1b) { /* escape */
420 t_con->state = TELNET_STATE_ESCAPE;
421 t_con->last_escape = '\x00';
422 } else if ((*buf_p == 0xd) || (*buf_p == 0xa)) { /* CR/LF */
425 /* skip over combinations with CR/LF and NUL characters */
426 if ((bytes_read > 1) && ((*(buf_p + 1) == 0xa) ||
427 (*(buf_p + 1) == 0xd))) {
431 if ((bytes_read > 1) && (*(buf_p + 1) == 0)) {
435 t_con->line[t_con->line_size] = 0;
437 telnet_write(connection, "\r\n\x00", 3);
439 if (strcmp(t_con->line, "history") == 0) {
440 retval = telnet_history_print(connection);
442 if (retval != ERROR_OK)
448 /* save only non-blank not repeating lines in the history */
449 char *prev_line = t_con->history[(t_con->current_history > 0) ?
450 t_con->current_history - 1 : TELNET_LINE_HISTORY_SIZE-1];
451 if (*t_con->line && (prev_line == NULL ||
452 strcmp(t_con->line, prev_line))) {
453 /* if the history slot is already taken, free it */
454 if (t_con->history[t_con->next_history])
455 free(t_con->history[t_con->next_history]);
457 /* add line to history */
458 t_con->history[t_con->next_history] = strdup(t_con->line);
460 /* wrap history at TELNET_LINE_HISTORY_SIZE */
461 t_con->next_history = (t_con->next_history + 1) %
462 TELNET_LINE_HISTORY_SIZE;
464 /* current history line starts at the new entry */
465 t_con->current_history =
468 if (t_con->history[t_con->current_history])
469 free(t_con->history[t_con->current_history]);
470 t_con->history[t_con->current_history] = strdup("");
473 t_con->line_size = 0;
475 /* to suppress prompt in log callback during command execution */
476 t_con->prompt_visible = false;
478 if (strcmp(t_con->line, "shutdown") == 0)
479 telnet_save_history(t_con);
481 retval = command_run_line(command_context, t_con->line);
483 t_con->line_cursor = 0;
484 t_con->prompt_visible = true;
486 if (retval == ERROR_COMMAND_CLOSE_CONNECTION)
487 return ERROR_SERVER_REMOTE_CLOSED;
489 /* the prompt is always * placed at the line beginning */
490 telnet_write(connection, "\r", 1);
492 retval = telnet_prompt(connection);
493 if (retval == ERROR_SERVER_REMOTE_CLOSED)
494 return ERROR_SERVER_REMOTE_CLOSED;
496 } else if ((*buf_p == 0x7f) || (*buf_p == 0x8)) { /* delete character */
497 if (t_con->line_cursor > 0) {
498 if (t_con->line_cursor != t_con->line_size) {
500 telnet_write(connection, "\b", 1);
501 t_con->line_cursor--;
503 memmove(t_con->line + t_con->line_cursor,
504 t_con->line + t_con->line_cursor + 1,
508 telnet_write(connection,
509 t_con->line + t_con->line_cursor,
512 telnet_write(connection, " \b", 2);
513 for (i = t_con->line_cursor; i < t_con->line_size; i++)
514 telnet_write(connection, "\b", 1);
517 t_con->line_cursor--;
518 /* back space: move the 'printer' head one char
519 * back, overwrite with space, move back again */
520 telnet_write(connection, "\b \b", 3);
523 } else if (*buf_p == 0x15) /* clear line */
524 telnet_clear_line(connection, t_con);
525 else if (*buf_p == CTRL('B')) { /* cursor left */
526 if (t_con->line_cursor > 0) {
527 telnet_write(connection, "\b", 1);
528 t_con->line_cursor--;
530 t_con->state = TELNET_STATE_DATA;
531 } else if (*buf_p == CTRL('F')) { /* cursor right */
532 if (t_con->line_cursor < t_con->line_size)
533 telnet_write(connection, t_con->line + t_con->line_cursor++, 1);
534 t_con->state = TELNET_STATE_DATA;
535 } else if (*buf_p == CTRL('P')) /* cursor up */
536 telnet_history_up(connection);
537 else if (*buf_p == CTRL('N')) /* cursor down */
538 telnet_history_down(connection);
539 else if (*buf_p == CTRL('A'))
540 telnet_move_cursor(connection, 0);
541 else if (*buf_p == CTRL('E'))
542 telnet_move_cursor(connection, t_con->line_size);
544 LOG_DEBUG("unhandled nonprintable: %2.2x", *buf_p);
548 case TELNET_STATE_IAC:
551 t_con->state = TELNET_STATE_DONT;
554 t_con->state = TELNET_STATE_DO;
557 t_con->state = TELNET_STATE_WONT;
560 t_con->state = TELNET_STATE_WILL;
564 case TELNET_STATE_SB:
566 case TELNET_STATE_SE:
568 case TELNET_STATE_WILL:
569 case TELNET_STATE_WONT:
570 case TELNET_STATE_DO:
571 case TELNET_STATE_DONT:
572 t_con->state = TELNET_STATE_DATA;
574 case TELNET_STATE_ESCAPE:
575 if (t_con->last_escape == '[') {
576 if (*buf_p == 'D') { /* cursor left */
577 if (t_con->line_cursor > 0) {
578 telnet_write(connection, "\b", 1);
579 t_con->line_cursor--;
581 t_con->state = TELNET_STATE_DATA;
582 } else if (*buf_p == 'C') { /* cursor right */
583 if (t_con->line_cursor < t_con->line_size)
584 telnet_write(connection,
585 t_con->line + t_con->line_cursor++, 1);
586 t_con->state = TELNET_STATE_DATA;
587 } else if (*buf_p == 'A') { /* cursor up */
588 telnet_history_up(connection);
589 } else if (*buf_p == 'B') { /* cursor down */
590 telnet_history_down(connection);
591 } else if (*buf_p == '3')
592 t_con->last_escape = *buf_p;
594 t_con->state = TELNET_STATE_DATA;
595 } else if (t_con->last_escape == '3') {
596 /* Remove character */
598 if (t_con->line_cursor < t_con->line_size) {
601 /* remove char from line buffer */
602 memmove(t_con->line + t_con->line_cursor,
603 t_con->line + t_con->line_cursor + 1,
604 t_con->line_size - t_con->line_cursor);
606 /* print remainder of buffer */
607 telnet_write(connection, t_con->line + t_con->line_cursor,
608 t_con->line_size - t_con->line_cursor);
609 /* overwrite last char with whitespace */
610 telnet_write(connection, " \b", 2);
612 /* move back to cursor position*/
613 for (i = t_con->line_cursor; i < t_con->line_size; i++)
614 telnet_write(connection, "\b", 1);
617 t_con->state = TELNET_STATE_DATA;
619 t_con->state = TELNET_STATE_DATA;
620 } else if (t_con->last_escape == '\x00') {
622 t_con->last_escape = *buf_p;
624 t_con->state = TELNET_STATE_DATA;
626 LOG_ERROR("BUG: unexpected value in t_con->last_escape");
627 t_con->state = TELNET_STATE_DATA;
632 LOG_ERROR("unknown telnet state");
643 static int telnet_connection_closed(struct connection *connection)
645 struct telnet_connection *t_con = connection->priv;
648 log_remove_callback(telnet_log_callback, connection);
652 t_con->prompt = NULL;
655 /* save telnet history */
656 telnet_save_history(t_con);
658 for (i = 0; i < TELNET_LINE_HISTORY_SIZE; i++) {
659 if (t_con->history[i]) {
660 free(t_con->history[i]);
661 t_con->history[i] = NULL;
665 /* if this connection registered a debug-message receiver delete it */
666 delete_debug_msg_receiver(connection->cmd_ctx, NULL);
668 if (connection->priv) {
669 free(connection->priv);
670 connection->priv = NULL;
672 LOG_ERROR("BUG: connection->priv == NULL");
677 int telnet_init(char *banner)
679 if (strcmp(telnet_port, "disabled") == 0) {
680 LOG_INFO("telnet server disabled");
684 struct telnet_service *telnet_service =
685 malloc(sizeof(struct telnet_service));
687 if (!telnet_service) {
688 LOG_ERROR("Failed to allocate telnet service.");
692 telnet_service->banner = banner;
694 int ret = add_service("telnet", telnet_port, CONNECTION_LIMIT_UNLIMITED,
695 telnet_new_connection, telnet_input, telnet_connection_closed,
698 if (ret != ERROR_OK) {
699 free(telnet_service);
706 /* daemon configuration command telnet_port */
707 COMMAND_HANDLER(handle_telnet_port_command)
709 return CALL_COMMAND_HANDLER(server_pipe_command, &telnet_port);
712 COMMAND_HANDLER(handle_exit_command)
714 return ERROR_COMMAND_CLOSE_CONNECTION;
717 static const struct command_registration telnet_command_handlers[] = {
720 .handler = handle_exit_command,
721 .mode = COMMAND_EXEC,
723 .help = "exit telnet session",
726 .name = "telnet_port",
727 .handler = handle_telnet_port_command,
728 .mode = COMMAND_CONFIG,
729 .help = "Specify port on which to listen "
730 "for incoming telnet connections. "
731 "Read help on 'gdb_port'.",
732 .usage = "[port_num]",
734 COMMAND_REGISTRATION_DONE
737 int telnet_register_commands(struct command_context *cmd_ctx)
739 telnet_port = strdup("4444");
740 return register_commands(cmd_ctx, NULL, telnet_command_handlers);
743 void telnet_service_free(void)