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server/server: Remove all exit() calls
[openocd.git] / src / server / telnet_server.c
blobe5eb4bb2368ab64fd065a7443ac7be5547bb2148
1 /***************************************************************************
2 * Copyright (C) 2005 by Dominic Rath *
3 * Dominic.Rath@gmx.de *
4 * *
5 * Copyright (C) 2007-2010 Øyvind Harboe *
6 * oyvind.harboe@zylin.com *
7 * *
8 * Copyright (C) 2008 by Spencer Oliver *
9 * spen@spen-soft.co.uk *
10 * *
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. *
15 * *
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. *
20 * *
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 ***************************************************************************/
24
25 #ifdef HAVE_CONFIG_H
26 #include "config.h"
27 #endif
28
29 #include "telnet_server.h"
30 #include <target/target_request.h>
31 #include <helper/configuration.h>
32
33 static char *telnet_port;
34
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 */
40
41 #define CTRL(c) (c - '@')
42 #define TELNET_HISTORY ".openocd_history"
43
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
46 * succeed. Shudder!
47 */
48 static int telnet_write(struct connection *connection, const void *data,
49 int len)
50 {
51 struct telnet_connection *t_con = connection->priv;
52 if (t_con->closed)
53 return ERROR_SERVER_REMOTE_CLOSED;
54
55 if (connection_write(connection, data, len) == len)
56 return ERROR_OK;
57 t_con->closed = 1;
58 return ERROR_SERVER_REMOTE_CLOSED;
59 }
60
61 static int telnet_prompt(struct connection *connection)
62 {
63 struct telnet_connection *t_con = connection->priv;
64
65 return telnet_write(connection, t_con->prompt, strlen(t_con->prompt));
66 }
67
68 static int telnet_outputline(struct connection *connection, const char *line)
69 {
70 int len;
71
72 /* process lines in buffer */
73 while (*line) {
74 char *line_end = strchr(line, '\n');
75
76 if (line_end)
77 len = line_end-line;
78 else
79 len = strlen(line);
80
81 telnet_write(connection, line, len);
82 if (line_end) {
83 telnet_write(connection, "\r\n", 2);
84 line += len + 1;
85 } else
86 line += len;
87 }
88
89 return ERROR_OK;
90 }
91
92 static int telnet_output(struct command_context *cmd_ctx, const char *line)
93 {
94 struct connection *connection = cmd_ctx->output_handler_priv;
95
96 return telnet_outputline(connection, line);
97 }
98
99 static void telnet_log_callback(void *priv, const char *file, unsigned line,
100 const char *function, const char *string)
101 {
102 struct connection *connection = priv;
103 struct telnet_connection *t_con = connection->priv;
104 int i;
105
106 /* if there is no prompt, simply output the message */
107 if (t_con->line_cursor < 0) {
108 telnet_outputline(connection, string);
109 return;
110 }
111
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);
119
120 /* output the message */
121 telnet_outputline(connection, string);
122
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);
128 }
129
130 static void telnet_load_history(struct telnet_connection *t_con)
131 {
132 FILE *histfp;
133 char buffer[TELNET_BUFFER_SIZE];
134 int i = 0;
135
136 char *history = get_home_dir(TELNET_HISTORY);
137
138 if (history == NULL) {
139 LOG_INFO("unable to get user home directory, telnet history will be disabled");
140 return;
141 }
142
143 histfp = fopen(history, "rb");
144
145 if (histfp) {
146
147 while (fgets(buffer, sizeof(buffer), histfp) != NULL) {
148
149 char *p = strchr(buffer, '\n');
150 if (p)
151 *p = '\0';
152 if (buffer[0] && i < TELNET_LINE_HISTORY_SIZE)
153 t_con->history[i++] = strdup(buffer);
154 }
155
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;
160 fclose(histfp);
161 }
162
163 free(history);
164 }
165
166 static void telnet_save_history(struct telnet_connection *t_con)
167 {
168 FILE *histfp;
169 int i;
170 int num;
171
172 char *history = get_home_dir(TELNET_HISTORY);
173
174 if (history == NULL) {
175 LOG_INFO("unable to get user home directory, telnet history will be disabled");
176 return;
177 }
178
179 histfp = fopen(history, "wb");
180
181 if (histfp) {
182
183 num = TELNET_LINE_HISTORY_SIZE;
184 i = t_con->current_history + 1;
185 i %= TELNET_LINE_HISTORY_SIZE;
186
187 while (t_con->history[i] == NULL && num > 0) {
188 i++;
189 i %= TELNET_LINE_HISTORY_SIZE;
190 num--;
191 }
192
193 if (num > 0) {
194 for (; num > 0; num--) {
195 fprintf(histfp, "%s\n", t_con->history[i]);
196 i++;
197 i %= TELNET_LINE_HISTORY_SIZE;
198 }
199 }
200 fclose(histfp);
201 }
202
203 free(history);
204 }
205
206 static int telnet_new_connection(struct connection *connection)
207 {
208 struct telnet_connection *telnet_connection;
209 struct telnet_service *telnet_service = connection->service->priv;
210 int i;
211
212 telnet_connection = malloc(sizeof(struct telnet_connection));
213
214 if (!telnet_connection) {
215 LOG_ERROR("Failed to allocate telnet connection.");
216 return ERROR_FAIL;
217 }
218
219 connection->priv = telnet_connection;
220
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;
228
229 /* output goes through telnet connection */
230 command_set_output_handler(connection->cmd_ctx, telnet_output, connection);
231
232 /* negotiate telnet options */
233 telnet_write(connection, negotiate, strlen(negotiate));
234
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);
239 }
240
241 /* the prompt is always placed at the line beginning */
242 telnet_write(connection, "\r", 1);
243 telnet_prompt(connection);
244
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);
251
252 log_add_callback(telnet_log_callback, connection);
253
254 return ERROR_OK;
255 }
256
257 static void telnet_clear_line(struct connection *connection,
258 struct telnet_connection *t_con)
259 {
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);
265
266 /* backspace, overwrite with space, backspace */
267 while (t_con->line_size > 0) {
268 telnet_write(connection, "\b \b", 3);
269 t_con->line_size--;
270 }
271 t_con->line_cursor = 0;
272 }
273
274 static void telnet_history_go(struct connection *connection, int idx)
275 {
276 struct telnet_connection *t_con = connection->priv;
277
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;
285 }
286 t_con->state = TELNET_STATE_DATA;
287 }
288
289 static void telnet_history_up(struct connection *connection)
290 {
291 struct telnet_connection *t_con = connection->priv;
292
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);
297 }
298
299 static void telnet_history_down(struct connection *connection)
300 {
301 struct telnet_connection *t_con = connection->priv;
302
303 int next_history = (t_con->current_history + 1) % TELNET_LINE_HISTORY_SIZE;
304 telnet_history_go(connection, next_history);
305 }
306
307 static int telnet_input(struct connection *connection)
308 {
309 int bytes_read;
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;
314
315 bytes_read = connection_read(connection, buffer, TELNET_BUFFER_SIZE);
316
317 if (bytes_read == 0)
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;
322 }
323
324 buf_p = buffer;
325 while (bytes_read) {
326 switch (t_con->state) {
327 case TELNET_STATE_DATA:
328 if (*buf_p == 0xff)
329 t_con->state = TELNET_STATE_IAC;
330 else {
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++;
342 } else {
343 int i;
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;
348 t_con->line_size++;
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);
355 }
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 */
361 int retval;
362
363 /* skip over combinations with CR/LF and NUL characters */
364 if ((bytes_read > 1) && ((*(buf_p + 1) == 0xa) ||
365 (*(buf_p + 1) == 0xd))) {
366 buf_p++;
367 bytes_read--;
368 }
369 if ((bytes_read > 1) && (*(buf_p + 1) == 0)) {
370 buf_p++;
371 bytes_read--;
372 }
373 t_con->line[t_con->line_size] = 0;
374
375 telnet_write(connection, "\r\n\x00", 3);
376
377 if (strcmp(t_con->line, "history") == 0) {
378 int i;
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->
383 next_history + i) %
384 TELNET_LINE_HISTORY_SIZE];
385 if (history_line) {
386 telnet_write(connection, history_line,
387 strlen(history_line));
388 telnet_write(connection, "\r\n\x00", 3);
389 }
390 }
391 t_con->line_size = 0;
392 t_con->line_cursor = 0;
393 continue;
394 }
395
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]);
404
405 /* add line to history */
406 t_con->history[t_con->next_history] = strdup(t_con->line);
407
408 /* wrap history at TELNET_LINE_HISTORY_SIZE */
409 t_con->next_history = (t_con->next_history + 1) %
410 TELNET_LINE_HISTORY_SIZE;
411
412 /* current history line starts at the new entry */
413 t_con->current_history =
414 t_con->next_history;
415
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("");
419 }
420
421 t_con->line_size = 0;
422
423 /* to suppress prompt in log callback during command execution */
424 t_con->line_cursor = -1;
425
426 if (strcmp(t_con->line, "shutdown") == 0)
427 telnet_save_history(t_con);
428
429 retval = command_run_line(command_context, t_con->line);
430
431 t_con->line_cursor = 0;
432
433 if (retval == ERROR_COMMAND_CLOSE_CONNECTION)
434 return ERROR_SERVER_REMOTE_CLOSED;
435
436 /* the prompt is always * placed at the line beginning */
437 telnet_write(connection, "\r", 1);
438
439 retval = telnet_prompt(connection);
440 if (retval == ERROR_SERVER_REMOTE_CLOSED)
441 return ERROR_SERVER_REMOTE_CLOSED;
442
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) {
446 int i;
447 telnet_write(connection, "\b", 1);
448 t_con->line_cursor--;
449 t_con->line_size--;
450 memmove(t_con->line + t_con->line_cursor,
451 t_con->line + t_con->line_cursor + 1,
452 t_con->line_size -
453 t_con->line_cursor);
454
455 telnet_write(connection,
456 t_con->line + t_con->line_cursor,
457 t_con->line_size -
458 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);
462 } else {
463 t_con->line_size--;
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);
468 }
469 }
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--;
476 }
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);
486 else
487 LOG_DEBUG("unhandled nonprintable: %2.2x", *buf_p);
488 }
489 }
490 break;
491 case TELNET_STATE_IAC:
492 switch (*buf_p) {
493 case 0xfe:
494 t_con->state = TELNET_STATE_DONT;
495 break;
496 case 0xfd:
497 t_con->state = TELNET_STATE_DO;
498 break;
499 case 0xfc:
500 t_con->state = TELNET_STATE_WONT;
501 break;
502 case 0xfb:
503 t_con->state = TELNET_STATE_WILL;
504 break;
505 }
506 break;
507 case TELNET_STATE_SB:
508 break;
509 case TELNET_STATE_SE:
510 break;
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;
516 break;
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--;
523 }
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;
536 else
537 t_con->state = TELNET_STATE_DATA;
538 } else if (t_con->last_escape == '3') {
539 /* Remove character */
540 if (*buf_p == '~') {
541 if (t_con->line_cursor < t_con->line_size) {
542 int i;
543 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);
548
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);
554
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);
558 }
559
560 t_con->state = TELNET_STATE_DATA;
561 } else
562 t_con->state = TELNET_STATE_DATA;
563 } else if (t_con->last_escape == '\x00') {
564 if (*buf_p == '[')
565 t_con->last_escape = *buf_p;
566 else
567 t_con->state = TELNET_STATE_DATA;
568 } else {
569 LOG_ERROR("BUG: unexpected value in t_con->last_escape");
570 t_con->state = TELNET_STATE_DATA;
571 }
572
573 break;
574 default:
575 LOG_ERROR("unknown telnet state");
576 exit(-1);
577 }
578
579 bytes_read--;
580 buf_p++;
581 }
582
583 return ERROR_OK;
584 }
585
586 static int telnet_connection_closed(struct connection *connection)
587 {
588 struct telnet_connection *t_con = connection->priv;
589 int i;
590
591 log_remove_callback(telnet_log_callback, connection);
592
593 if (t_con->prompt) {
594 free(t_con->prompt);
595 t_con->prompt = NULL;
596 }
597
598 /* save telnet history */
599 telnet_save_history(t_con);
600
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;
605 }
606 }
607
608 /* if this connection registered a debug-message receiver delete it */
609 delete_debug_msg_receiver(connection->cmd_ctx, NULL);
610
611 if (connection->priv) {
612 free(connection->priv);
613 connection->priv = NULL;
614 } else
615 LOG_ERROR("BUG: connection->priv == NULL");
616
617 return ERROR_OK;
618 }
619
620 int telnet_init(char *banner)
621 {
622 if (strcmp(telnet_port, "disabled") == 0) {
623 LOG_INFO("telnet server disabled");
624 return ERROR_OK;
625 }
626
627 struct telnet_service *telnet_service =
628 malloc(sizeof(struct telnet_service));
629
630 if (!telnet_service) {
631 LOG_ERROR("Failed to allocate telnet service.");
632 return ERROR_FAIL;
633 }
634
635 telnet_service->banner = banner;
636
637 int ret = add_service("telnet", telnet_port, CONNECTION_LIMIT_UNLIMITED,
638 telnet_new_connection, telnet_input, telnet_connection_closed,
639 telnet_service);
640
641 if (ret != ERROR_OK) {
642 free(telnet_service);
643 return ret;
644 }
645
646 return ERROR_OK;
647 }
648
649 /* daemon configuration command telnet_port */
650 COMMAND_HANDLER(handle_telnet_port_command)
651 {
652 return CALL_COMMAND_HANDLER(server_pipe_command, &telnet_port);
653 }
654
655 COMMAND_HANDLER(handle_exit_command)
656 {
657 return ERROR_COMMAND_CLOSE_CONNECTION;
658 }
659
660 static const struct command_registration telnet_command_handlers[] = {
661 {
662 .name = "exit",
663 .handler = handle_exit_command,
664 .mode = COMMAND_EXEC,
665 .usage = "",
666 .help = "exit telnet session",
667 },
668 {
669 .name = "telnet_port",
670 .handler = handle_telnet_port_command,
671 .mode = COMMAND_ANY,
672 .help = "Specify port on which to listen "
673 "for incoming telnet connections. "
674 "Read help on 'gdb_port'.",
675 .usage = "[port_num]",
676 },
677 COMMAND_REGISTRATION_DONE
678 };
679
680 int telnet_register_commands(struct command_context *cmd_ctx)
681 {
682 telnet_port = strdup("4444");
683 return register_commands(cmd_ctx, NULL, telnet_command_handlers);
684 }
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