f26ad9f6717ad555efaecbb3e93ddfc9c4a74241
[fw/openocd] / src / server / telnet_server.c
1 /***************************************************************************
2  *   Copyright (C) 2005 by Dominic Rath                                    *
3  *   Dominic.Rath@gmx.de                                                   *
4  *                                                                         *
5  *   Copyright (C) 2007,2008 Ã˜yvind 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, write to the                         *
23  *   Free Software Foundation, Inc.,                                       *
24  *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
25  ***************************************************************************/
26 #ifdef HAVE_CONFIG_H
27 #include "config.h"
28 #endif
29
30 #include "telnet_server.h"
31 #include "target_request.h"
32
33 static unsigned short telnet_port = 4444;
34
35 int handle_exit_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc);
36 int handle_telnet_port_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc);
37
38 static char *negotiate =
39                 "\xFF\xFB\x03"          /* IAC WILL Suppress Go Ahead */
40                 "\xFF\xFB\x01"          /* IAC WILL Echo */
41                 "\xFF\xFD\x03"          /* IAC DO Suppress Go Ahead */
42                 "\xFF\xFE\x01";         /* IAC DON'T Echo */
43
44 #define CTRL(c) (c - '@')
45
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
48  * succeed. Shudder!
49  */
50 int telnet_write(connection_t *connection, const void *data, int len)
51 {
52         telnet_connection_t *t_con = connection->priv;
53         if (t_con->closed)
54                 return ERROR_SERVER_REMOTE_CLOSED;
55
56         if (write_socket(connection->fd, data, len) == len)
57         {
58                 return ERROR_OK;
59         }
60         t_con->closed = 1;
61         return ERROR_SERVER_REMOTE_CLOSED;
62 }
63
64 int telnet_prompt(connection_t *connection)
65 {
66         telnet_connection_t *t_con = connection->priv;
67
68         telnet_write(connection, "\r", 1); /* the prompt is always placed at the line beginning */
69         return telnet_write(connection, t_con->prompt, strlen(t_con->prompt));
70 }
71
72 int telnet_outputline(connection_t *connection, const char *line)
73 {
74         int len;
75
76         /* process lines in buffer */
77         while (*line) {
78                 char *line_end = strchr(line, '\n');
79
80                 if (line_end)
81                         len = line_end-line;
82                 else
83                         len = strlen(line);
84
85                 telnet_write(connection, line, len);
86                 if (line_end)
87                 {
88                         telnet_write(connection, "\r\n", 2);
89                         line += len + 1;
90                 }
91                 else
92                 {
93                         line += len;
94                 }
95         }
96
97         return ERROR_OK;
98 }
99
100 int telnet_output(struct command_context_s *cmd_ctx, const char* line)
101 {
102         connection_t *connection = cmd_ctx->output_handler_priv;
103
104         return telnet_outputline(connection, line);
105 }
106
107 void telnet_log_callback(void *priv, const char *file, int line,
108                 const char *function, const char *string)
109 {
110         connection_t *connection = priv;
111         telnet_connection_t *t_con = connection->priv;
112         int i;
113
114         /* if there is no prompt, simply output the message */
115         if (t_con->line_cursor < 0)
116         {
117                 telnet_outputline(connection, string);
118                 return;
119         }
120
121         /* clear the command line */
122         telnet_write(connection, "\r", 1);
123         for (i = strlen(t_con->prompt) + t_con->line_size; i > 0; i -= 16)
124                 telnet_write(connection, "                ", i > 16 ? 16 : i);
125         telnet_write(connection, "\r", 1);
126
127         /* output the message */
128         telnet_outputline(connection, string);
129
130         /* put the command line to its previous state */
131         telnet_prompt(connection);
132         telnet_write(connection, t_con->line, t_con->line_size);
133         for (i = t_con->line_size; i > t_con->line_cursor; i--)
134                 telnet_write(connection, "\b", 1);
135 }
136
137 int telnet_new_connection(connection_t *connection)
138 {
139         telnet_connection_t *telnet_connection = malloc(sizeof(telnet_connection_t));
140         telnet_service_t *telnet_service = connection->service->priv;
141         int i;
142
143         connection->priv = telnet_connection;
144
145         /* initialize telnet connection information */
146         telnet_connection->closed = 0;
147         telnet_connection->line_size = 0;
148         telnet_connection->line_cursor = 0;
149         telnet_connection->option_size = 0;
150         telnet_connection->prompt = strdup("> ");
151         telnet_connection->state = TELNET_STATE_DATA;
152
153         /* output goes through telnet connection */
154         command_set_output_handler(connection->cmd_ctx, telnet_output, connection);
155
156         /* negotiate telnet options */
157         telnet_write(connection, negotiate, strlen(negotiate));
158
159         /* print connection banner */
160         if (telnet_service->banner)
161         {
162                 telnet_write(connection, telnet_service->banner, strlen(telnet_service->banner));
163                 telnet_write(connection, "\r\n", 2);
164         }
165
166         telnet_prompt(connection);
167
168         /* initialize history */
169         for (i = 0; i < TELNET_LINE_HISTORY_SIZE; i++)
170         {
171                 telnet_connection->history[i] = NULL;
172         }
173         telnet_connection->next_history = 0;
174         telnet_connection->current_history = 0;
175
176         log_add_callback(telnet_log_callback, connection);
177
178         return ERROR_OK;
179 }
180
181 void telnet_clear_line(connection_t *connection, telnet_connection_t *t_con)
182 {
183         /* move to end of line */
184         if (t_con->line_cursor < t_con->line_size)
185         {
186                 telnet_write(connection, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor);
187         }
188
189         /* backspace, overwrite with space, backspace */
190         while (t_con->line_size > 0)
191         {
192                 telnet_write(connection, "\b \b", 3);
193                 t_con->line_size--;
194         }
195         t_con->line_cursor = 0;
196 }
197
198 int telnet_input(connection_t *connection)
199 {
200         int bytes_read;
201         char buffer[TELNET_BUFFER_SIZE];
202         char *buf_p;
203         telnet_connection_t *t_con = connection->priv;
204         command_context_t *command_context = connection->cmd_ctx;
205
206         bytes_read = read_socket(connection->fd, buffer, TELNET_BUFFER_SIZE);
207
208         if (bytes_read == 0)
209                 return ERROR_SERVER_REMOTE_CLOSED;
210         else if (bytes_read == -1)
211         {
212                 LOG_ERROR("error during read: %s", strerror(errno));
213                 return ERROR_SERVER_REMOTE_CLOSED;
214         }
215
216         buf_p = buffer;
217         while (bytes_read)
218         {
219                 switch (t_con->state)
220                 {
221                         case TELNET_STATE_DATA:
222                                 if (*buf_p == '\xff')
223                                 {
224                                         t_con->state = TELNET_STATE_IAC;
225                                 }
226                                 else
227                                 {
228                                         if (isprint(*buf_p)) /* printable character */
229                                         {
230                                                 /* watch buffer size leaving one spare character for string null termination */
231                                                 if (t_con->line_size == TELNET_LINE_MAX_SIZE-1)
232                                                 {
233                                                         /* output audible bell if buffer is full */
234                                                         telnet_write(connection, "\x07", 1); /* "\a" does not work, at least on windows */
235                                                 }
236                                                 else if (t_con->line_cursor == t_con->line_size)
237                                                 {
238                                                         telnet_write(connection, buf_p, 1);
239                                                         t_con->line[t_con->line_size++] = *buf_p;
240                                                         t_con->line_cursor++;
241                                                 }
242                                                 else
243                                                 {
244                                                         int i;
245                                                         memmove(t_con->line + t_con->line_cursor + 1, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor);
246                                                         t_con->line[t_con->line_cursor] = *buf_p;
247                                                         t_con->line_size++;
248                                                         telnet_write(connection, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor);
249                                                         t_con->line_cursor++;
250                                                         for (i = t_con->line_cursor; i < t_con->line_size; i++)
251                                                         {
252                                                                 telnet_write(connection, "\b", 1);
253                                                         }
254                                                 }
255                                         }
256                                         else /* non-printable */
257                                         {
258                                                 if (*buf_p == 0x1b) /* escape */
259                                                 {
260                                                         t_con->state = TELNET_STATE_ESCAPE;
261                                                         t_con->last_escape = '\x00';
262                                                 }
263                                                 else if ((*buf_p == 0xd) || (*buf_p == 0xa)) /* CR/LF */
264                                                 {
265                                                         int retval;
266
267                                                         /* skip over combinations with CR/LF and NUL characters */
268                                                         if ((bytes_read > 1) && ((*(buf_p + 1) == 0xa) || (*(buf_p + 1) == 0xd)))
269                                                         {
270                                                                 buf_p++;
271                                                                 bytes_read--;
272                                                         }
273                                                         if ((bytes_read > 1) && (*(buf_p + 1) == 0))
274                                                         {
275                                                                 buf_p++;
276                                                                 bytes_read--;
277                                                         }
278                                                         t_con->line[t_con->line_size] = 0;
279
280                                                         telnet_write(connection, "\r\n\x00", 3);
281
282                                                         if (strcmp(t_con->line, "history") == 0)
283                                                         {
284                                                                 int i;
285                                                                 for (i = 1; i < TELNET_LINE_HISTORY_SIZE; i++)
286                                                                 {
287                                                                         /* the t_con->next_history line contains empty string (unless NULL), thus it is not printed */
288                                                                         char *history_line = t_con->history[(t_con->next_history + i) % TELNET_LINE_HISTORY_SIZE];
289                                                                         if (history_line)
290                                                                         {
291                                                                                 telnet_write(connection, history_line, strlen(history_line));
292                                                                                 telnet_write(connection, "\r\n\x00", 3);
293                                                                         }
294                                                                 }
295                                                                 t_con->line_size = 0;
296                                                                 t_con->line_cursor = 0;
297                                                                 continue;
298                                                         }
299
300                                                         /* save only non-blank not repeating lines in the history */
301                                                         char *prev_line = t_con->history[(t_con->current_history > 0) ? t_con->current_history - 1 : TELNET_LINE_HISTORY_SIZE-1];
302                                                         if (*t_con->line && (prev_line == NULL || strcmp(t_con->line, prev_line)))
303                                                         {
304                                                                 /* if the history slot is already taken, free it */
305                                                                 if (t_con->history[t_con->next_history])
306                                                                 {
307                                                                         free(t_con->history[t_con->next_history]);
308                                                                 }
309
310                                                                 /* add line to history */
311                                                                 t_con->history[t_con->next_history] = strdup(t_con->line);
312
313                                                                 /* wrap history at TELNET_LINE_HISTORY_SIZE */
314                                                                 t_con->next_history = (t_con->next_history + 1) % TELNET_LINE_HISTORY_SIZE;
315
316                                                                 /* current history line starts at the new entry */
317                                                                 t_con->current_history = t_con->next_history;
318
319                                                                 if (t_con->history[t_con->current_history])
320                                                                 {
321                                                                         free(t_con->history[t_con->current_history]);
322                                                                 }
323                                                                 t_con->history[t_con->current_history] = strdup("");
324                                                         }
325
326                                                         t_con->line_size = 0;
327
328                                                         t_con->line_cursor = -1; /* to supress prompt in log callback during command execution */
329
330                                                         retval = command_run_line(command_context, t_con->line);
331
332                                                         t_con->line_cursor = 0;
333
334                                                         if (retval == ERROR_COMMAND_CLOSE_CONNECTION)
335                                                                 return ERROR_SERVER_REMOTE_CLOSED;
336
337                                                         retval = telnet_prompt(connection);
338                                                         if (retval == ERROR_SERVER_REMOTE_CLOSED)
339                                                                 return ERROR_SERVER_REMOTE_CLOSED;
340
341                                                 }
342                                                 else if ((*buf_p == 0x7f) || (*buf_p == 0x8)) /* delete character */
343                                                 {
344                                                         if (t_con->line_cursor > 0)
345                                                         {
346                                                                 if (t_con->line_cursor != t_con->line_size)
347                                                                 {
348                                                                         int i;
349                                                                         telnet_write(connection, "\b", 1);
350                                                                         t_con->line_cursor--;
351                                                                         t_con->line_size--;
352                                                                         memmove(t_con->line + t_con->line_cursor, t_con->line + t_con->line_cursor + 1, t_con->line_size - t_con->line_cursor);
353
354                                                                         telnet_write(connection, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor);
355                                                                         telnet_write(connection, " \b", 2);
356                                                                         for (i = t_con->line_cursor; i < t_con->line_size; i++)
357                                                                         {
358                                                                                 telnet_write(connection, "\b", 1);
359                                                                         }
360                                                                 }
361                                                                 else
362                                                                 {
363                                                                         t_con->line_size--;
364                                                                         t_con->line_cursor--;
365                                                                         /* back space: move the 'printer' head one char back, overwrite with space, move back again */
366                                                                         telnet_write(connection, "\b \b", 3);
367                                                                 }
368                                                         }
369                                                 }
370                                                 else if (*buf_p == 0x15) /* clear line */
371                                                 {
372                                                         telnet_clear_line(connection, t_con);
373                                                 }
374                                                 else if (*buf_p == CTRL('B')) /* cursor left */
375                                                 {
376                                                         if (t_con->line_cursor > 0)
377                                                         {
378                                                                 telnet_write(connection, "\b", 1);
379                                                                 t_con->line_cursor--;
380                                                         }
381                                                         t_con->state = TELNET_STATE_DATA;
382                                                 }
383                                                 else if (*buf_p == CTRL('F')) /* cursor right */
384                                                 {
385                                                         if (t_con->line_cursor < t_con->line_size)
386                                                         {
387                                                                 telnet_write(connection, t_con->line + t_con->line_cursor++, 1);
388                                                         }
389                                                         t_con->state = TELNET_STATE_DATA;
390                                                 }
391                                                 else
392                                                 {
393                                                         LOG_DEBUG("unhandled nonprintable: %2.2x", *buf_p);
394                                                 }
395                                         }
396                                 }
397                                 break;
398                         case TELNET_STATE_IAC:
399                                 switch (*buf_p)
400                                 {
401                                         case '\xfe':
402                                                 t_con->state = TELNET_STATE_DONT;
403                                                 break;
404                                         case '\xfd':
405                                                 t_con->state = TELNET_STATE_DO;
406                                                 break;
407                                         case '\xfc':
408                                                 t_con->state = TELNET_STATE_WONT;
409                                                 break;
410                                         case '\xfb':
411                                                 t_con->state = TELNET_STATE_WILL;
412                                                 break;
413                                 }
414                                 break;
415                         case TELNET_STATE_SB:
416                                 break;
417                         case TELNET_STATE_SE:
418                                 break;
419                         case TELNET_STATE_WILL:
420                         case TELNET_STATE_WONT:
421                         case TELNET_STATE_DO:
422                         case TELNET_STATE_DONT:
423                                 t_con->state = TELNET_STATE_DATA;
424                                 break;
425                         case TELNET_STATE_ESCAPE:
426                                 if (t_con->last_escape == '[')
427                                 {
428                                         if (*buf_p == 'D') /* cursor left */
429                                         {
430                                                 if (t_con->line_cursor > 0)
431                                                 {
432                                                         telnet_write(connection, "\b", 1);
433                                                         t_con->line_cursor--;
434                                                 }
435                                                 t_con->state = TELNET_STATE_DATA;
436                                         }
437                                         else if (*buf_p == 'C') /* cursor right */
438                                         {
439                                                 if (t_con->line_cursor < t_con->line_size)
440                                                 {
441                                                         telnet_write(connection, t_con->line + t_con->line_cursor++, 1);
442                                                 }
443                                                 t_con->state = TELNET_STATE_DATA;
444                                         }
445                                         else if (*buf_p == 'A') /* cursor up */
446                                         {
447                                                 int last_history = (t_con->current_history > 0) ? t_con->current_history - 1 : TELNET_LINE_HISTORY_SIZE-1;
448                                                 if (t_con->history[last_history])
449                                                 {
450                                                         telnet_clear_line(connection, t_con);
451                                                         t_con->line_size = strlen(t_con->history[last_history]);
452                                                         t_con->line_cursor = t_con->line_size;
453                                                         memcpy(t_con->line, t_con->history[last_history], t_con->line_size);
454                                                         telnet_write(connection, t_con->line, t_con->line_size);
455                                                         t_con->current_history = last_history;
456                                                 }
457                                                 t_con->state = TELNET_STATE_DATA;
458                                         }
459                                         else if (*buf_p == 'B') /* cursor down */
460                                         {
461                                                 int next_history = (t_con->current_history + 1) % TELNET_LINE_HISTORY_SIZE;
462                                                 if (t_con->history[next_history])
463                                                 {
464                                                         telnet_clear_line(connection, t_con);
465                                                         t_con->line_size = strlen(t_con->history[next_history]);
466                                                         t_con->line_cursor = t_con->line_size;
467                                                         memcpy(t_con->line, t_con->history[next_history], t_con->line_size);
468                                                         telnet_write(connection, t_con->line, t_con->line_size);
469                                                         t_con->current_history = next_history;
470                                                 }
471                                                 t_con->state = TELNET_STATE_DATA;
472                                         }
473                                         else if (*buf_p == '3')
474                                         {
475                                                 t_con->last_escape = *buf_p;
476                                         }
477                                         else
478                                         {
479                                                 t_con->state = TELNET_STATE_DATA;
480                                         }
481                                 }
482                                 else if (t_con->last_escape == '3')
483                                 {
484                                         /* Remove character */
485                                         if (*buf_p == '~')
486                                         {
487                                                 if (t_con->line_cursor < t_con->line_size)
488                                                 {
489                                                         int i;
490                                                         t_con->line_size--;
491                                                         /* remove char from line buffer */
492                                                         memmove(t_con->line + t_con->line_cursor, t_con->line + t_con->line_cursor + 1, t_con->line_size - t_con->line_cursor);
493
494                                                         /* print remainder of buffer */
495                                                         telnet_write(connection, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor);
496                                                         /* overwrite last char with whitespace */
497                                                         telnet_write(connection, " \b", 2);
498
499                                                         /* move back to cursor position*/
500                                                         for (i = t_con->line_cursor; i < t_con->line_size; i++)
501                                                         {
502                                                                 telnet_write(connection, "\b", 1);
503                                                         }
504                                                 }
505
506                                                 t_con->state = TELNET_STATE_DATA;
507                                         }
508                                         else
509                                         {
510                                                 t_con->state = TELNET_STATE_DATA;
511                                         }
512                                 }
513                                 else if (t_con->last_escape == '\x00')
514                                 {
515                                         if (*buf_p == '[')
516                                         {
517                                                 t_con->last_escape = *buf_p;
518                                         }
519                                         else
520                                         {
521                                                 t_con->state = TELNET_STATE_DATA;
522                                         }
523                                 }
524                                 else
525                                 {
526                                         LOG_ERROR("BUG: unexpected value in t_con->last_escape");
527                                         t_con->state = TELNET_STATE_DATA;
528                                 }
529
530                                 break;
531                         default:
532                                 LOG_ERROR("unknown telnet state");
533                                 exit(-1);
534                 }
535
536                 bytes_read--;
537                 buf_p++;
538         }
539
540         return ERROR_OK;
541 }
542
543 int telnet_connection_closed(connection_t *connection)
544 {
545         telnet_connection_t *t_con = connection->priv;
546         int i;
547
548         log_remove_callback(telnet_log_callback, connection);
549
550         if (t_con->prompt)
551         {
552                 free(t_con->prompt);
553                 t_con->prompt = NULL;
554         }
555
556         for (i = 0; i < TELNET_LINE_HISTORY_SIZE; i++)
557         {
558                 if (t_con->history[i])
559                 {
560                         free(t_con->history[i]);
561                         t_con->history[i] = NULL;
562                 }
563         }
564
565         /* if this connection registered a debug-message receiver delete it */
566         delete_debug_msg_receiver(connection->cmd_ctx, NULL);
567
568         if (connection->priv)
569         {
570                 free(connection->priv);
571                 connection->priv = NULL;
572         }
573         else
574         {
575                 LOG_ERROR("BUG: connection->priv == NULL");
576         }
577
578         return ERROR_OK;
579 }
580
581 int telnet_set_prompt(connection_t *connection, char *prompt)
582 {
583         telnet_connection_t *t_con = connection->priv;
584
585         if (t_con->prompt != NULL)
586                 free(t_con->prompt);
587
588         t_con->prompt = strdup(prompt);
589
590         return ERROR_OK;
591 }
592
593 int telnet_init(char *banner)
594 {
595         telnet_service_t *telnet_service = malloc(sizeof(telnet_service_t));
596
597         if (telnet_port == 0)
598         {
599                 LOG_INFO("telnet port disabled");
600                 free(telnet_service);
601                 return ERROR_OK;
602         }
603
604         telnet_service->banner = banner;
605
606         add_service("telnet", CONNECTION_TCP, telnet_port, 1, telnet_new_connection, telnet_input, telnet_connection_closed, telnet_service);
607
608         return ERROR_OK;
609 }
610
611 int telnet_register_commands(command_context_t *command_context)
612 {
613         register_command(command_context, NULL, "exit", handle_exit_command,
614                                          COMMAND_EXEC, "exit telnet session");
615
616         register_command(command_context, NULL, "telnet_port", handle_telnet_port_command,
617                                          COMMAND_ANY, "port on which to listen for incoming telnet connections");
618
619         return ERROR_OK;
620 }
621
622 /* daemon configuration command telnet_port */
623 int handle_telnet_port_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc)
624 {
625         if (argc == 0)
626         {
627                 command_print(cmd_ctx, "%d", telnet_port);
628                 return ERROR_OK;
629         }
630
631         telnet_port = strtoul(args[0], NULL, 0);
632
633         return ERROR_OK;
634 }
635
636 int handle_exit_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc)
637 {
638         return ERROR_COMMAND_CLOSE_CONNECTION;
639 }