- Fix problems with stuck telnet sessions. Thanks to √ėyvind Harboe for this patch.
[openocd.git] / src / server / telnet_server.c
1 /***************************************************************************
2 * Copyright (C) 2005 by Dominic Rath *
3 * Dominic.Rath@gmx.de *
4 * *
5 * This program is free software; you can redistribute it and/or modify *
6 * it under the terms of the GNU General Public License as published by *
7 * the Free Software Foundation; either version 2 of the License, or *
8 * (at your option) any later version. *
9 * *
10 * This program is distributed in the hope that it will be useful, *
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of *
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
13 * GNU General Public License for more details. *
14 * *
15 * You should have received a copy of the GNU General Public License *
16 * along with this program; if not, write to the *
17 * Free Software Foundation, Inc., *
18 * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. *
19 ***************************************************************************/
20 #ifdef HAVE_CONFIG_H
21 #include "config.h"
22 #endif
23
24 #include "replacements.h"
25
26 #include "telnet_server.h"
27
28 #include "server.h"
29 #include "log.h"
30 #include "command.h"
31 #include "target.h"
32 #include "target_request.h"
33
34 #include <stdlib.h>
35 #include <unistd.h>
36 #include <errno.h>
37 #include <string.h>
38 #include <ctype.h>
39
40 static unsigned short telnet_port = 0;
41
42 int handle_exit_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc);
43 int handle_telnet_port_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc);
44
45 static char *negotiate =
46 "\xFF\xFB\x03" /* IAC WILL Suppress Go Ahead */
47 "\xFF\xFB\x01" /* IAC WILL Echo */
48 "\xFF\xFD\x03" /* IAC DO Suppress Go Ahead */
49 "\xFF\xFE\x01"; /* IAC DON'T Echo */
50
51 #define CTRL(c) (c - '@')
52
53
54 /* The only way we can detect that the socket is closed is the first time
55 * we write to it, we will fail. Subsequent write operations will
56 * succeed. Shudder!
57 */
58 int telnet_write(connection_t *connection, void *data, int len)
59 {
60 telnet_connection_t *t_con = connection->priv;
61 if (t_con->closed)
62 return ERROR_SERVER_REMOTE_CLOSED;
63
64 if (write_socket(connection->fd, data, len)==len)
65 {
66 return ERROR_OK;
67 }
68 t_con->closed=1;
69 return ERROR_SERVER_REMOTE_CLOSED;
70 }
71
72
73 int telnet_prompt(connection_t *connection)
74 {
75 telnet_connection_t *t_con = connection->priv;
76
77 return telnet_write(connection, t_con->prompt, strlen(t_con->prompt));
78 }
79
80 int telnet_outputline(connection_t *connection, char* line)
81 {
82 telnet_write(connection, line, strlen(line));
83 return telnet_write(connection, "\r\n\0", 3);
84 }
85
86
87 int telnet_output(struct command_context_s *cmd_ctx, char* line)
88 {
89 connection_t *connection = cmd_ctx->output_handler_priv;
90
91 return telnet_outputline(connection, line);
92 }
93
94 void telnet_log_callback(void *priv, const char *file, int line,
95 const char *function, const char *format, va_list args)
96 {
97 connection_t *connection = priv;
98 char *t=allocPrintf(format, args);
99 if (t==NULL)
100 return;
101
102 telnet_outputline(connection, t);
103
104 free(t);
105 }
106
107
108 int telnet_target_callback_event_handler(struct target_s *target, enum target_event event, void *priv)
109 {
110 struct command_context_s *cmd_ctx = priv;
111 char buffer[512];
112
113 switch (event)
114 {
115 case TARGET_EVENT_HALTED:
116 command_print(cmd_ctx, "Target %i halted", get_num_by_target(target));
117 target->type->arch_state(target, buffer, 512);
118 buffer[511] = 0;
119 command_print(cmd_ctx, "%s", buffer);
120 break;
121 case TARGET_EVENT_RESUMED:
122 command_print(cmd_ctx, "Target %i resumed", get_num_by_target(target));
123 break;
124 default:
125 break;
126 }
127
128 return ERROR_OK;
129 }
130
131 int telnet_new_connection(connection_t *connection)
132 {
133 telnet_connection_t *telnet_connection = malloc(sizeof(telnet_connection_t));
134 telnet_service_t *telnet_service = connection->service->priv;
135 int i;
136
137 connection->priv = telnet_connection;
138
139 /* initialize telnet connection information */
140 telnet_connection->closed = 0;
141 telnet_connection->line_size = 0;
142 telnet_connection->line_cursor = 0;
143 telnet_connection->option_size = 0;
144 telnet_connection->prompt = strdup("> ");
145 telnet_connection->state = TELNET_STATE_DATA;
146
147 /* output goes through telnet connection */
148 command_set_output_handler(connection->cmd_ctx, telnet_output, connection);
149
150 /* negotiate telnet options */
151 telnet_write(connection, negotiate, strlen(negotiate));
152
153 /* print connection banner */
154 if (telnet_service->banner)
155 {
156 telnet_write(connection, telnet_service->banner, strlen(telnet_service->banner));
157 telnet_write(connection, "\r\n\0", 3);
158 }
159
160 telnet_prompt(connection);
161
162 /* initialize history */
163 for (i = 0; i < TELNET_LINE_HISTORY_SIZE; i++)
164 {
165 telnet_connection->history[i] = NULL;
166 }
167 telnet_connection->next_history = 0;
168 telnet_connection->current_history = 0;
169
170 target_register_event_callback(telnet_target_callback_event_handler, connection->cmd_ctx);
171
172 return ERROR_OK;
173 }
174
175 void telnet_clear_line(connection_t *connection, telnet_connection_t *t_con)
176 {
177 /* move to end of line */
178 if (t_con->line_cursor < t_con->line_size)
179 {
180 telnet_write(connection, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor);
181 }
182
183 /* backspace, overwrite with space, backspace */
184 while (t_con->line_size > 0)
185 {
186 telnet_write(connection, "\b \b", 3);
187 t_con->line_size--;
188 }
189 t_con->line_cursor = 0;
190 }
191
192 int telnet_input(connection_t *connection)
193 {
194 int bytes_read;
195 char buffer[TELNET_BUFFER_SIZE];
196 char *buf_p;
197 telnet_connection_t *t_con = connection->priv;
198 command_context_t *command_context = connection->cmd_ctx;
199
200 bytes_read = read_socket(connection->fd, buffer, TELNET_BUFFER_SIZE);
201
202 if (bytes_read == 0)
203 return ERROR_SERVER_REMOTE_CLOSED;
204 else if (bytes_read == -1)
205 {
206 ERROR("error during read: %s", strerror(errno));
207 return ERROR_SERVER_REMOTE_CLOSED;
208 }
209
210 buf_p = buffer;
211 while (bytes_read)
212 {
213 switch (t_con->state)
214 {
215 case TELNET_STATE_DATA:
216 if (*buf_p == '\xff')
217 {
218 t_con->state = TELNET_STATE_IAC;
219 }
220 else
221 {
222 if (isprint(*buf_p)) /* printable character */
223 {
224 telnet_write(connection, buf_p, 1);
225 if (t_con->line_cursor == t_con->line_size)
226 {
227 t_con->line[t_con->line_size++] = *buf_p;
228 t_con->line_cursor++;
229 }
230 else
231 {
232 int i;
233 memmove(t_con->line + t_con->line_cursor + 1, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor);
234 t_con->line[t_con->line_cursor++] = *buf_p;
235 t_con->line_size++;
236 telnet_write(connection, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor);
237 for (i = t_con->line_cursor; i < t_con->line_size; i++)
238 {
239 telnet_write(connection, "\b", 1);
240 }
241 }
242 }
243 else /* non-printable */
244 {
245 if (*buf_p == 0x1b) /* escape */
246 {
247 t_con->state = TELNET_STATE_ESCAPE;
248 t_con->last_escape = '\x00';
249 }
250 else if ((*buf_p == 0xd) || (*buf_p == 0xa)) /* CR/LF */
251 {
252 int retval;
253
254 /* skip over combinations with CR/LF + NUL */
255 if (((*(buf_p + 1) == 0xa) || (*(buf_p + 1) == 0xd)) && (bytes_read > 1))
256 {
257 buf_p++;
258 bytes_read--;
259 }
260 if ((*(buf_p + 1) == 0) && (bytes_read > 1))
261 {
262 buf_p++;
263 bytes_read--;
264 }
265 t_con->line[t_con->line_size] = 0;
266
267 telnet_write(connection, "\r\n\x00", 3);
268
269 if (strcmp(t_con->line, "history") == 0)
270 {
271 int i;
272 for (i = 0; i < TELNET_LINE_HISTORY_SIZE; i++)
273 {
274 if (t_con->history[i])
275 {
276 telnet_write(connection, t_con->history[i], strlen(t_con->history[i]));
277 telnet_write(connection, "\r\n\x00", 3);
278 }
279 }
280 telnet_prompt(connection);
281 t_con->line_size = 0;
282 t_con->line_cursor = 0;
283 continue;
284 }
285
286 log_setCallback(telnet_log_callback, connection);
287
288 if ((retval = command_run_line(command_context, t_con->line)) != ERROR_OK)
289 {
290 if (retval == ERROR_COMMAND_CLOSE_CONNECTION)
291 {
292 return ERROR_SERVER_REMOTE_CLOSED;
293 }
294 }
295
296 /* Save only non-blank lines in the history */
297 if (t_con->line_size > 0)
298 {
299 /* if the history slot is already taken, free it */
300 if (t_con->history[t_con->next_history])
301 {
302 free(t_con->history[t_con->next_history]);
303 }
304
305 /* add line to history */
306 t_con->history[t_con->next_history] = strdup(t_con->line);
307
308 /* wrap history at TELNET_LINE_HISTORY_SIZE */
309 t_con->next_history = (t_con->next_history + 1) % TELNET_LINE_HISTORY_SIZE;
310
311 /* current history line starts at the new entry */
312 t_con->current_history = t_con->next_history;
313
314 if (t_con->history[t_con->current_history])
315 {
316 free(t_con->history[t_con->current_history]);
317 }
318 t_con->history[t_con->current_history] = strdup("");
319 }
320
321 int t=telnet_prompt(connection);
322 if (t==ERROR_SERVER_REMOTE_CLOSED)
323 return t;
324
325 t_con->line_size = 0;
326 t_con->line_cursor = 0;
327 }
328 else if ((*buf_p == 0x7f) || (*buf_p == 0x8)) /* delete character */
329 {
330 if (t_con->line_cursor > 0)
331 {
332 if (t_con->line_cursor != t_con->line_size)
333 {
334 int i;
335 telnet_write(connection, "\b", 1);
336 t_con->line_cursor--;
337 t_con->line_size--;
338 memmove(t_con->line + t_con->line_cursor, t_con->line + t_con->line_cursor + 1, t_con->line_size - t_con->line_cursor);
339
340 telnet_write(connection, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor);
341 telnet_write(connection, " \b", 2);
342 for (i = t_con->line_cursor; i < t_con->line_size; i++)
343 {
344 telnet_write(connection, "\b", 1);
345 }
346 }
347 else
348 {
349 t_con->line_size--;
350 t_con->line_cursor--;
351 /* back space: move the 'printer' head one char back, overwrite with space, move back again */
352 telnet_write(connection, "\b \b", 3);
353 }
354 }
355 }
356 else if (*buf_p == 0x15) /* clear line */
357 {
358 telnet_clear_line(connection, t_con);
359 }
360 else if (*buf_p == CTRL('B')) /* cursor left */
361 {
362 if (t_con->line_cursor > 0)
363 {
364 telnet_write(connection, "\b", 1);
365 t_con->line_cursor--;
366 }
367 t_con->state = TELNET_STATE_DATA;
368 }
369 else if (*buf_p == CTRL('F')) /* cursor right */
370 {
371 if (t_con->line_cursor < t_con->line_size)
372 {
373 telnet_write(connection, t_con->line + t_con->line_cursor++, 1);
374 }
375 t_con->state = TELNET_STATE_DATA;
376 }
377 else
378 {
379 DEBUG("unhandled nonprintable: %2.2x", *buf_p);
380 }
381 }
382 }
383 break;
384 case TELNET_STATE_IAC:
385 switch (*buf_p)
386 {
387 case '\xfe':
388 t_con->state = TELNET_STATE_DONT;
389 break;
390 case '\xfd':
391 t_con->state = TELNET_STATE_DO;
392 break;
393 case '\xfc':
394 t_con->state = TELNET_STATE_WONT;
395 break;
396 case '\xfb':
397 t_con->state = TELNET_STATE_WILL;
398 break;
399 }
400 break;
401 case TELNET_STATE_SB:
402 break;
403 case TELNET_STATE_SE:
404 break;
405 case TELNET_STATE_WILL:
406 case TELNET_STATE_WONT:
407 case TELNET_STATE_DO:
408 case TELNET_STATE_DONT:
409 t_con->state = TELNET_STATE_DATA;
410 break;
411 case TELNET_STATE_ESCAPE:
412 if (t_con->last_escape == '[')
413 {
414 if (*buf_p == 'D') /* cursor left */
415 {
416 if (t_con->line_cursor > 0)
417 {
418 telnet_write(connection, "\b", 1);
419 t_con->line_cursor--;
420 }
421 t_con->state = TELNET_STATE_DATA;
422 }
423 else if (*buf_p == 'C') /* cursor right */
424 {
425 if (t_con->line_cursor < t_con->line_size)
426 {
427 telnet_write(connection, t_con->line + t_con->line_cursor++, 1);
428 }
429 t_con->state = TELNET_STATE_DATA;
430 }
431 else if (*buf_p == 'A') /* cursor up */
432 {
433 int last_history = (t_con->current_history > 0) ? t_con->current_history - 1 : TELNET_LINE_HISTORY_SIZE-1;
434 if (t_con->history[last_history])
435 {
436 telnet_clear_line(connection, t_con);
437 t_con->line_size = strlen(t_con->history[last_history]);
438 t_con->line_cursor = t_con->line_size;
439 memcpy(t_con->line, t_con->history[last_history], t_con->line_size + 1);
440 telnet_write(connection, t_con->line, t_con->line_size);
441 t_con->current_history = last_history;
442 }
443 t_con->state = TELNET_STATE_DATA;
444 }
445 else if (*buf_p == 'B') /* cursor down */
446 {
447 int next_history = (t_con->current_history + 1) % TELNET_LINE_HISTORY_SIZE;
448 if (t_con->history[next_history])
449 {
450 telnet_clear_line(connection, t_con);
451 t_con->line_size = strlen(t_con->history[next_history]);
452 t_con->line_cursor = t_con->line_size;
453 memcpy(t_con->line, t_con->history[next_history], t_con->line_size + 1);
454 telnet_write(connection, t_con->line, t_con->line_size);
455 t_con->current_history = next_history;
456 }
457 t_con->state = TELNET_STATE_DATA;
458 }
459 else if (*buf_p == '3')
460 {
461 t_con->last_escape = *buf_p;
462 }
463 else
464 {
465 t_con->state = TELNET_STATE_DATA;
466 }
467 }
468 else if (t_con->last_escape == '3')
469 {
470 /* Remove character */
471 if (*buf_p == '~')
472 {
473 if (t_con->line_cursor < t_con->line_size)
474 {
475 int i;
476 t_con->line_size--;
477 /* remove char from line buffer */
478 memmove(t_con->line + t_con->line_cursor, t_con->line + t_con->line_cursor + 1, t_con->line_size - t_con->line_cursor);
479
480 /* print remainder of buffer */
481 telnet_write(connection, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor);
482 /* overwrite last char with whitespace */
483 telnet_write(connection, " \b", 2);
484
485 /* move back to cursor position*/
486 for (i = t_con->line_cursor; i < t_con->line_size; i++)
487 {
488 telnet_write(connection, "\b", 1);
489 }
490 }
491
492 t_con->state = TELNET_STATE_DATA;
493 }
494 else
495 {
496 t_con->state = TELNET_STATE_DATA;
497 }
498 }
499 else if (t_con->last_escape == '\x00')
500 {
501 if (*buf_p == '[')
502 {
503 t_con->last_escape = *buf_p;
504 }
505 else
506 {
507 t_con->state = TELNET_STATE_DATA;
508 }
509 }
510 else
511 {
512 ERROR("BUG: unexpected value in t_con->last_escape");
513 t_con->state = TELNET_STATE_DATA;
514 }
515
516 break;
517 default:
518 ERROR("unknown telnet state");
519 exit(-1);
520 }
521
522 bytes_read--;
523 buf_p++;
524 }
525
526 return ERROR_OK;
527 }
528
529 int telnet_connection_closed(connection_t *connection)
530 {
531 telnet_connection_t *t_con = connection->priv;
532 int i;
533
534 if (t_con->prompt)
535 {
536 free(t_con->prompt);
537 t_con->prompt = NULL;
538 }
539
540 for (i = 0; i < TELNET_LINE_HISTORY_SIZE; i++)
541 {
542 if (t_con->history[i])
543 {
544 free(t_con->history[i]);
545 t_con->history[i] = NULL;
546 }
547 }
548
549 /* if this connection registered a debug-message receiver delete it */
550 delete_debug_msg_receiver(connection->cmd_ctx, NULL);
551
552 if (connection->priv)
553 {
554 free(connection->priv);
555 connection->priv = NULL;
556 }
557 else
558 {
559 ERROR("BUG: connection->priv == NULL");
560 }
561
562 target_unregister_event_callback(telnet_target_callback_event_handler, connection->cmd_ctx);
563
564 return ERROR_OK;
565 }
566
567 int telnet_set_prompt(connection_t *connection, char *prompt)
568 {
569 telnet_connection_t *t_con = connection->priv;
570
571 t_con->prompt = strdup(prompt);
572
573 return ERROR_OK;
574 }
575
576 int telnet_init(char *banner)
577 {
578 telnet_service_t *telnet_service = malloc(sizeof(telnet_service_t));
579
580 if (telnet_port == 0)
581 {
582 WARNING("no telnet port specified, using default port 4444");
583 telnet_port = 4444;
584 }
585
586 telnet_service->banner = banner;
587
588 add_service("telnet", CONNECTION_TELNET, telnet_port, 1, telnet_new_connection, telnet_input, telnet_connection_closed, telnet_service);
589
590 return ERROR_OK;
591 }
592
593 int telnet_register_commands(command_context_t *command_context)
594 {
595 register_command(command_context, NULL, "exit", handle_exit_command,
596 COMMAND_EXEC, "exit telnet session");
597
598 register_command(command_context, NULL, "telnet_port", handle_telnet_port_command,
599 COMMAND_CONFIG, "");
600
601 return ERROR_OK;
602 }
603
604 /* daemon configuration command telnet_port */
605 int handle_telnet_port_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc)
606 {
607 if (argc == 0)
608 return ERROR_OK;
609
610 /* only if the port wasn't overwritten by cmdline */
611 if (telnet_port == 0)
612 telnet_port = strtoul(args[0], NULL, 0);
613
614 return ERROR_OK;
615 }
616
617 int handle_exit_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc)
618 {
619 return ERROR_COMMAND_CLOSE_CONNECTION;
620 }