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 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. *
25 ***************************************************************************/
31 #include "telnet_server.h"
32 #include <target/target_request.h>
33 #include <helper/configuration.h>
35 static char *telnet_port;
37 static char *negotiate =
38 "\xFF\xFB\x03" /* IAC WILL Suppress Go Ahead */
39 "\xFF\xFB\x01" /* IAC WILL Echo */
40 "\xFF\xFD\x03" /* IAC DO Suppress Go Ahead */
41 "\xFF\xFE\x01"; /* IAC DON'T Echo */
43 #define CTRL(c) (c - '@')
44 #define TELNET_HISTORY ".openocd_history"
46 /* The only way we can detect that the socket is closed is the first time
47 * we write to it, we will fail. Subsequent write operations will
50 static int telnet_write(struct connection *connection, const void *data,
53 struct telnet_connection *t_con = connection->priv;
55 return ERROR_SERVER_REMOTE_CLOSED;
57 if (connection_write(connection, data, len) == len)
60 return ERROR_SERVER_REMOTE_CLOSED;
63 static int telnet_prompt(struct connection *connection)
65 struct telnet_connection *t_con = connection->priv;
67 return telnet_write(connection, t_con->prompt, strlen(t_con->prompt));
70 static int telnet_outputline(struct connection *connection, const char *line)
74 /* process lines in buffer */
76 char *line_end = strchr(line, '\n');
83 telnet_write(connection, line, len);
85 telnet_write(connection, "\r\n", 2);
94 static int telnet_output(struct command_context *cmd_ctx, const char *line)
96 struct connection *connection = cmd_ctx->output_handler_priv;
98 return telnet_outputline(connection, line);
101 static void telnet_log_callback(void *priv, const char *file, unsigned line,
102 const char *function, const char *string)
104 struct connection *connection = priv;
105 struct telnet_connection *t_con = connection->priv;
108 /* if there is no prompt, simply output the message */
109 if (t_con->line_cursor < 0) {
110 telnet_outputline(connection, string);
114 /* clear the command line */
115 for (i = strlen(t_con->prompt) + t_con->line_size; i > 0; i -= 16)
116 telnet_write(connection, "\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b", i > 16 ? 16 : i);
117 for (i = strlen(t_con->prompt) + t_con->line_size; i > 0; i -= 16)
118 telnet_write(connection, " ", i > 16 ? 16 : i);
119 for (i = strlen(t_con->prompt) + t_con->line_size; i > 0; i -= 16)
120 telnet_write(connection, "\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b", i > 16 ? 16 : i);
122 /* output the message */
123 telnet_outputline(connection, string);
125 /* put the command line to its previous state */
126 telnet_prompt(connection);
127 telnet_write(connection, t_con->line, t_con->line_size);
128 for (i = t_con->line_size; i > t_con->line_cursor; i--)
129 telnet_write(connection, "\b", 1);
132 static void telnet_load_history(struct telnet_connection *t_con)
135 char buffer[TELNET_BUFFER_SIZE];
138 char *history = get_home_dir(TELNET_HISTORY);
140 if (history == NULL) {
141 LOG_INFO("unable to get user home directory, telnet history will be disabled");
145 histfp = fopen(history, "rb");
149 while (fgets(buffer, sizeof(buffer), histfp) != NULL) {
151 char *p = strchr(buffer, '\n');
154 if (buffer[0] && i < TELNET_LINE_HISTORY_SIZE)
155 t_con->history[i++] = strdup(buffer);
158 t_con->next_history = i;
159 t_con->next_history %= TELNET_LINE_HISTORY_SIZE;
160 /* try to set to last entry - 1, that way we skip over any exit/shutdown cmds */
161 t_con->current_history = t_con->next_history > 0 ? i - 1 : 0;
168 static void telnet_save_history(struct telnet_connection *t_con)
174 char *history = get_home_dir(TELNET_HISTORY);
176 if (history == NULL) {
177 LOG_INFO("unable to get user home directory, telnet history will be disabled");
181 histfp = fopen(history, "wb");
185 num = TELNET_LINE_HISTORY_SIZE;
186 i = t_con->current_history + 1;
187 i %= TELNET_LINE_HISTORY_SIZE;
189 while (t_con->history[i] == NULL && num > 0) {
191 i %= TELNET_LINE_HISTORY_SIZE;
196 for (; num > 0; num--) {
197 fprintf(histfp, "%s\n", t_con->history[i]);
199 i %= TELNET_LINE_HISTORY_SIZE;
208 static int telnet_new_connection(struct connection *connection)
210 struct telnet_connection *telnet_connection;
211 struct telnet_service *telnet_service = connection->service->priv;
214 telnet_connection = malloc(sizeof(struct telnet_connection));
216 if (!telnet_connection) {
217 LOG_ERROR("Failed to allocate telnet connection.");
221 connection->priv = telnet_connection;
223 /* initialize telnet connection information */
224 telnet_connection->closed = 0;
225 telnet_connection->line_size = 0;
226 telnet_connection->line_cursor = 0;
227 telnet_connection->option_size = 0;
228 telnet_connection->prompt = strdup("> ");
229 telnet_connection->state = TELNET_STATE_DATA;
231 /* output goes through telnet connection */
232 command_set_output_handler(connection->cmd_ctx, telnet_output, connection);
234 /* negotiate telnet options */
235 telnet_write(connection, negotiate, strlen(negotiate));
237 /* print connection banner */
238 if (telnet_service->banner) {
239 telnet_write(connection, telnet_service->banner, strlen(telnet_service->banner));
240 telnet_write(connection, "\r\n", 2);
243 /* the prompt is always placed at the line beginning */
244 telnet_write(connection, "\r", 1);
245 telnet_prompt(connection);
247 /* initialize history */
248 for (i = 0; i < TELNET_LINE_HISTORY_SIZE; i++)
249 telnet_connection->history[i] = NULL;
250 telnet_connection->next_history = 0;
251 telnet_connection->current_history = 0;
252 telnet_load_history(telnet_connection);
254 log_add_callback(telnet_log_callback, connection);
259 static void telnet_clear_line(struct connection *connection,
260 struct telnet_connection *t_con)
262 /* move to end of line */
263 if (t_con->line_cursor < t_con->line_size)
264 telnet_write(connection,
265 t_con->line + t_con->line_cursor,
266 t_con->line_size - t_con->line_cursor);
268 /* backspace, overwrite with space, backspace */
269 while (t_con->line_size > 0) {
270 telnet_write(connection, "\b \b", 3);
273 t_con->line_cursor = 0;
276 static void telnet_history_go(struct connection *connection, int idx)
278 struct telnet_connection *t_con = connection->priv;
280 if (t_con->history[idx]) {
281 telnet_clear_line(connection, t_con);
282 t_con->line_size = strlen(t_con->history[idx]);
283 t_con->line_cursor = t_con->line_size;
284 memcpy(t_con->line, t_con->history[idx], t_con->line_size);
285 telnet_write(connection, t_con->line, t_con->line_size);
286 t_con->current_history = idx;
288 t_con->state = TELNET_STATE_DATA;
291 static void telnet_history_up(struct connection *connection)
293 struct telnet_connection *t_con = connection->priv;
295 int last_history = (t_con->current_history > 0) ?
296 t_con->current_history - 1 :
297 TELNET_LINE_HISTORY_SIZE-1;
298 telnet_history_go(connection, last_history);
301 static void telnet_history_down(struct connection *connection)
303 struct telnet_connection *t_con = connection->priv;
305 int next_history = (t_con->current_history + 1) % TELNET_LINE_HISTORY_SIZE;
306 telnet_history_go(connection, next_history);
309 static int telnet_input(struct connection *connection)
312 unsigned char buffer[TELNET_BUFFER_SIZE];
313 unsigned char *buf_p;
314 struct telnet_connection *t_con = connection->priv;
315 struct command_context *command_context = connection->cmd_ctx;
317 bytes_read = connection_read(connection, buffer, TELNET_BUFFER_SIZE);
320 return ERROR_SERVER_REMOTE_CLOSED;
321 else if (bytes_read == -1) {
322 LOG_ERROR("error during read: %s", strerror(errno));
323 return ERROR_SERVER_REMOTE_CLOSED;
328 switch (t_con->state) {
329 case TELNET_STATE_DATA:
331 t_con->state = TELNET_STATE_IAC;
333 if (isprint(*buf_p)) { /* printable character */
334 /* watch buffer size leaving one spare character for
335 * string null termination */
336 if (t_con->line_size == TELNET_LINE_MAX_SIZE-1) {
337 /* output audible bell if buffer is full
338 * "\a" does not work, at least on windows */
339 telnet_write(connection, "\x07", 1);
340 } else if (t_con->line_cursor == t_con->line_size) {
341 telnet_write(connection, buf_p, 1);
342 t_con->line[t_con->line_size++] = *buf_p;
343 t_con->line_cursor++;
346 memmove(t_con->line + t_con->line_cursor + 1,
347 t_con->line + t_con->line_cursor,
348 t_con->line_size - t_con->line_cursor);
349 t_con->line[t_con->line_cursor] = *buf_p;
351 telnet_write(connection,
352 t_con->line + t_con->line_cursor,
353 t_con->line_size - t_con->line_cursor);
354 t_con->line_cursor++;
355 for (i = t_con->line_cursor; i < t_con->line_size; i++)
356 telnet_write(connection, "\b", 1);
358 } else { /* non-printable */
359 if (*buf_p == 0x1b) { /* escape */
360 t_con->state = TELNET_STATE_ESCAPE;
361 t_con->last_escape = '\x00';
362 } else if ((*buf_p == 0xd) || (*buf_p == 0xa)) { /* CR/LF */
365 /* skip over combinations with CR/LF and NUL characters */
366 if ((bytes_read > 1) && ((*(buf_p + 1) == 0xa) ||
367 (*(buf_p + 1) == 0xd))) {
371 if ((bytes_read > 1) && (*(buf_p + 1) == 0)) {
375 t_con->line[t_con->line_size] = 0;
377 telnet_write(connection, "\r\n\x00", 3);
379 if (strcmp(t_con->line, "history") == 0) {
381 for (i = 1; i < TELNET_LINE_HISTORY_SIZE; i++) {
382 /* the t_con->next_history line contains empty string
383 * (unless NULL), thus it is not printed */
384 char *history_line = t_con->history[(t_con->
386 TELNET_LINE_HISTORY_SIZE];
388 telnet_write(connection, history_line,
389 strlen(history_line));
390 telnet_write(connection, "\r\n\x00", 3);
393 t_con->line_size = 0;
394 t_con->line_cursor = 0;
398 /* save only non-blank not repeating lines in the history */
399 char *prev_line = t_con->history[(t_con->current_history > 0) ?
400 t_con->current_history - 1 : TELNET_LINE_HISTORY_SIZE-1];
401 if (*t_con->line && (prev_line == NULL ||
402 strcmp(t_con->line, prev_line))) {
403 /* if the history slot is already taken, free it */
404 if (t_con->history[t_con->next_history])
405 free(t_con->history[t_con->next_history]);
407 /* add line to history */
408 t_con->history[t_con->next_history] = strdup(t_con->line);
410 /* wrap history at TELNET_LINE_HISTORY_SIZE */
411 t_con->next_history = (t_con->next_history + 1) %
412 TELNET_LINE_HISTORY_SIZE;
414 /* current history line starts at the new entry */
415 t_con->current_history =
418 if (t_con->history[t_con->current_history])
419 free(t_con->history[t_con->current_history]);
420 t_con->history[t_con->current_history] = strdup("");
423 t_con->line_size = 0;
425 /* to suppress prompt in log callback during command execution */
426 t_con->line_cursor = -1;
428 if (strcmp(t_con->line, "shutdown") == 0)
429 telnet_save_history(t_con);
431 retval = command_run_line(command_context, t_con->line);
433 t_con->line_cursor = 0;
435 if (retval == ERROR_COMMAND_CLOSE_CONNECTION)
436 return ERROR_SERVER_REMOTE_CLOSED;
438 /* the prompt is always * placed at the line beginning */
439 telnet_write(connection, "\r", 1);
441 retval = telnet_prompt(connection);
442 if (retval == ERROR_SERVER_REMOTE_CLOSED)
443 return ERROR_SERVER_REMOTE_CLOSED;
445 } else if ((*buf_p == 0x7f) || (*buf_p == 0x8)) { /* delete character */
446 if (t_con->line_cursor > 0) {
447 if (t_con->line_cursor != t_con->line_size) {
449 telnet_write(connection, "\b", 1);
450 t_con->line_cursor--;
452 memmove(t_con->line + t_con->line_cursor,
453 t_con->line + t_con->line_cursor + 1,
457 telnet_write(connection,
458 t_con->line + t_con->line_cursor,
461 telnet_write(connection, " \b", 2);
462 for (i = t_con->line_cursor; i < t_con->line_size; i++)
463 telnet_write(connection, "\b", 1);
466 t_con->line_cursor--;
467 /* back space: move the 'printer' head one char
468 * back, overwrite with space, move back again */
469 telnet_write(connection, "\b \b", 3);
472 } else if (*buf_p == 0x15) /* clear line */
473 telnet_clear_line(connection, t_con);
474 else if (*buf_p == CTRL('B')) { /* cursor left */
475 if (t_con->line_cursor > 0) {
476 telnet_write(connection, "\b", 1);
477 t_con->line_cursor--;
479 t_con->state = TELNET_STATE_DATA;
480 } else if (*buf_p == CTRL('F')) { /* cursor right */
481 if (t_con->line_cursor < t_con->line_size)
482 telnet_write(connection, t_con->line + t_con->line_cursor++, 1);
483 t_con->state = TELNET_STATE_DATA;
484 } else if (*buf_p == CTRL('P')) /* cursor up */
485 telnet_history_up(connection);
486 else if (*buf_p == CTRL('N')) /* cursor down */
487 telnet_history_down(connection);
489 LOG_DEBUG("unhandled nonprintable: %2.2x", *buf_p);
493 case TELNET_STATE_IAC:
496 t_con->state = TELNET_STATE_DONT;
499 t_con->state = TELNET_STATE_DO;
502 t_con->state = TELNET_STATE_WONT;
505 t_con->state = TELNET_STATE_WILL;
509 case TELNET_STATE_SB:
511 case TELNET_STATE_SE:
513 case TELNET_STATE_WILL:
514 case TELNET_STATE_WONT:
515 case TELNET_STATE_DO:
516 case TELNET_STATE_DONT:
517 t_con->state = TELNET_STATE_DATA;
519 case TELNET_STATE_ESCAPE:
520 if (t_con->last_escape == '[') {
521 if (*buf_p == 'D') { /* cursor left */
522 if (t_con->line_cursor > 0) {
523 telnet_write(connection, "\b", 1);
524 t_con->line_cursor--;
526 t_con->state = TELNET_STATE_DATA;
527 } else if (*buf_p == 'C') { /* cursor right */
528 if (t_con->line_cursor < t_con->line_size)
529 telnet_write(connection,
530 t_con->line + t_con->line_cursor++, 1);
531 t_con->state = TELNET_STATE_DATA;
532 } else if (*buf_p == 'A') { /* cursor up */
533 telnet_history_up(connection);
534 } else if (*buf_p == 'B') { /* cursor down */
535 telnet_history_down(connection);
536 } else if (*buf_p == '3')
537 t_con->last_escape = *buf_p;
539 t_con->state = TELNET_STATE_DATA;
540 } else if (t_con->last_escape == '3') {
541 /* Remove character */
543 if (t_con->line_cursor < t_con->line_size) {
546 /* remove char from line buffer */
547 memmove(t_con->line + t_con->line_cursor,
548 t_con->line + t_con->line_cursor + 1,
549 t_con->line_size - t_con->line_cursor);
551 /* print remainder of buffer */
552 telnet_write(connection, t_con->line + t_con->line_cursor,
553 t_con->line_size - t_con->line_cursor);
554 /* overwrite last char with whitespace */
555 telnet_write(connection, " \b", 2);
557 /* move back to cursor position*/
558 for (i = t_con->line_cursor; i < t_con->line_size; i++)
559 telnet_write(connection, "\b", 1);
562 t_con->state = TELNET_STATE_DATA;
564 t_con->state = TELNET_STATE_DATA;
565 } else if (t_con->last_escape == '\x00') {
567 t_con->last_escape = *buf_p;
569 t_con->state = TELNET_STATE_DATA;
571 LOG_ERROR("BUG: unexpected value in t_con->last_escape");
572 t_con->state = TELNET_STATE_DATA;
577 LOG_ERROR("unknown telnet state");
588 static int telnet_connection_closed(struct connection *connection)
590 struct telnet_connection *t_con = connection->priv;
593 log_remove_callback(telnet_log_callback, connection);
597 t_con->prompt = NULL;
600 /* save telnet history */
601 telnet_save_history(t_con);
603 for (i = 0; i < TELNET_LINE_HISTORY_SIZE; i++) {
604 if (t_con->history[i]) {
605 free(t_con->history[i]);
606 t_con->history[i] = NULL;
610 /* if this connection registered a debug-message receiver delete it */
611 delete_debug_msg_receiver(connection->cmd_ctx, NULL);
613 if (connection->priv) {
614 free(connection->priv);
615 connection->priv = NULL;
617 LOG_ERROR("BUG: connection->priv == NULL");
622 int telnet_init(char *banner)
624 if (strcmp(telnet_port, "disabled") == 0) {
625 LOG_INFO("telnet server disabled");
629 struct telnet_service *telnet_service;
631 telnet_service = malloc(sizeof(struct telnet_service));
633 if (!telnet_service) {
634 LOG_ERROR("Failed to allocate telnet service.");
638 telnet_service->banner = banner;
640 return add_service("telnet",
642 CONNECTION_LIMIT_UNLIMITED,
643 telnet_new_connection,
645 telnet_connection_closed,
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);