1 /***************************************************************************
2 * Copyright (C) 2005 by Dominic Rath *
3 * Dominic.Rath@gmx.de *
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. *
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. *
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 ***************************************************************************/
24 #include "replacements.h"
26 #include "telnet_server.h"
32 #include "target_request.h"
40 static unsigned short telnet_port = 0;
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);
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 */
51 #define CTRL(c) (c - '@')
53 /* The only way we can detect that the socket is closed is the first time
54 * we write to it, we will fail. Subsequent write operations will
57 int telnet_write(connection_t *connection, const void *data, int len)
59 telnet_connection_t *t_con = connection->priv;
61 return ERROR_SERVER_REMOTE_CLOSED;
63 if (write_socket(connection->fd, data, len) == len)
68 return ERROR_SERVER_REMOTE_CLOSED;
71 int telnet_prompt(connection_t *connection)
73 telnet_connection_t *t_con = connection->priv;
75 return telnet_write(connection, t_con->prompt, strlen(t_con->prompt));
78 int telnet_outputline(connection_t *connection, const char *line)
82 /* process lines in buffer */
84 char *line_end = strchr(line, '\n');
91 telnet_write(connection, line, len);
94 telnet_write(connection, "\r\n\0", 3);
106 int telnet_output(struct command_context_s *cmd_ctx, char* line)
108 connection_t *connection = cmd_ctx->output_handler_priv;
110 return telnet_outputline(connection, line);
113 void telnet_log_callback(void *priv, const char *file, int line,
114 const char *function, const char *string)
116 connection_t *connection = priv;
117 telnet_outputline(connection, string);
120 int telnet_target_callback_event_handler(struct target_s *target, enum target_event event, void *priv)
124 case TARGET_EVENT_HALTED:
125 target_arch_state(target);
134 int telnet_new_connection(connection_t *connection)
136 telnet_connection_t *telnet_connection = malloc(sizeof(telnet_connection_t));
137 telnet_service_t *telnet_service = connection->service->priv;
140 connection->priv = telnet_connection;
142 /* initialize telnet connection information */
143 telnet_connection->closed = 0;
144 telnet_connection->line_size = 0;
145 telnet_connection->line_cursor = 0;
146 telnet_connection->option_size = 0;
147 telnet_connection->prompt = strdup("> ");
148 telnet_connection->state = TELNET_STATE_DATA;
150 /* output goes through telnet connection */
151 command_set_output_handler(connection->cmd_ctx, telnet_output, connection);
153 /* negotiate telnet options */
154 telnet_write(connection, negotiate, strlen(negotiate));
156 /* print connection banner */
157 if (telnet_service->banner)
159 telnet_write(connection, telnet_service->banner, strlen(telnet_service->banner));
160 telnet_write(connection, "\r\n\0", 3);
163 telnet_prompt(connection);
165 /* initialize history */
166 for (i = 0; i < TELNET_LINE_HISTORY_SIZE; i++)
168 telnet_connection->history[i] = NULL;
170 telnet_connection->next_history = 0;
171 telnet_connection->current_history = 0;
173 target_register_event_callback(telnet_target_callback_event_handler, connection->cmd_ctx);
175 log_add_callback(telnet_log_callback, connection);
182 void telnet_clear_line(connection_t *connection, telnet_connection_t *t_con)
184 /* move to end of line */
185 if (t_con->line_cursor < t_con->line_size)
187 telnet_write(connection, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor);
190 /* backspace, overwrite with space, backspace */
191 while (t_con->line_size > 0)
193 telnet_write(connection, "\b \b", 3);
196 t_con->line_cursor = 0;
199 int telnet_input(connection_t *connection)
202 char buffer[TELNET_BUFFER_SIZE];
204 telnet_connection_t *t_con = connection->priv;
205 command_context_t *command_context = connection->cmd_ctx;
207 bytes_read = read_socket(connection->fd, buffer, TELNET_BUFFER_SIZE);
210 return ERROR_SERVER_REMOTE_CLOSED;
211 else if (bytes_read == -1)
213 ERROR("error during read: %s", strerror(errno));
214 return ERROR_SERVER_REMOTE_CLOSED;
220 switch (t_con->state)
222 case TELNET_STATE_DATA:
223 if (*buf_p == '\xff')
225 t_con->state = TELNET_STATE_IAC;
229 if (isprint(*buf_p)) /* printable character */
231 telnet_write(connection, buf_p, 1);
232 if (t_con->line_cursor == t_con->line_size)
234 t_con->line[t_con->line_size++] = *buf_p;
235 t_con->line_cursor++;
240 memmove(t_con->line + t_con->line_cursor + 1, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor);
241 t_con->line[t_con->line_cursor++] = *buf_p;
243 telnet_write(connection, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor);
244 for (i = t_con->line_cursor; i < t_con->line_size; i++)
246 telnet_write(connection, "\b", 1);
250 else /* non-printable */
252 if (*buf_p == 0x1b) /* escape */
254 t_con->state = TELNET_STATE_ESCAPE;
255 t_con->last_escape = '\x00';
257 else if ((*buf_p == 0xd) || (*buf_p == 0xa)) /* CR/LF */
261 /* skip over combinations with CR/LF + NUL */
262 if (((*(buf_p + 1) == 0xa) || (*(buf_p + 1) == 0xd)) && (bytes_read > 1))
267 if ((*(buf_p + 1) == 0) && (bytes_read > 1))
272 t_con->line[t_con->line_size] = 0;
274 telnet_write(connection, "\r\n\x00", 3);
276 if (strcmp(t_con->line, "history") == 0)
279 for (i = 0; i < TELNET_LINE_HISTORY_SIZE; i++)
281 if (t_con->history[i])
283 telnet_write(connection, t_con->history[i], strlen(t_con->history[i]));
284 telnet_write(connection, "\r\n\x00", 3);
287 telnet_prompt(connection);
288 t_con->line_size = 0;
289 t_con->line_cursor = 0;
293 retval = command_run_line(command_context, t_con->line);
295 if (retval == ERROR_COMMAND_CLOSE_CONNECTION)
297 return ERROR_SERVER_REMOTE_CLOSED;
300 /* Save only non-blank lines in the history */
301 if (t_con->line_size > 0)
303 /* if the history slot is already taken, free it */
304 if (t_con->history[t_con->next_history])
306 free(t_con->history[t_con->next_history]);
309 /* add line to history */
310 t_con->history[t_con->next_history] = strdup(t_con->line);
312 /* wrap history at TELNET_LINE_HISTORY_SIZE */
313 t_con->next_history = (t_con->next_history + 1) % TELNET_LINE_HISTORY_SIZE;
315 /* current history line starts at the new entry */
316 t_con->current_history = t_con->next_history;
318 if (t_con->history[t_con->current_history])
320 free(t_con->history[t_con->current_history]);
322 t_con->history[t_con->current_history] = strdup("");
325 int t = telnet_prompt(connection);
326 if (t == ERROR_SERVER_REMOTE_CLOSED)
329 t_con->line_size = 0;
330 t_con->line_cursor = 0;
332 else if ((*buf_p == 0x7f) || (*buf_p == 0x8)) /* delete character */
334 if (t_con->line_cursor > 0)
336 if (t_con->line_cursor != t_con->line_size)
339 telnet_write(connection, "\b", 1);
340 t_con->line_cursor--;
342 memmove(t_con->line + t_con->line_cursor, t_con->line + t_con->line_cursor + 1, t_con->line_size - t_con->line_cursor);
344 telnet_write(connection, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor);
345 telnet_write(connection, " \b", 2);
346 for (i = t_con->line_cursor; i < t_con->line_size; i++)
348 telnet_write(connection, "\b", 1);
354 t_con->line_cursor--;
355 /* back space: move the 'printer' head one char back, overwrite with space, move back again */
356 telnet_write(connection, "\b \b", 3);
360 else if (*buf_p == 0x15) /* clear line */
362 telnet_clear_line(connection, t_con);
364 else if (*buf_p == CTRL('B')) /* cursor left */
366 if (t_con->line_cursor > 0)
368 telnet_write(connection, "\b", 1);
369 t_con->line_cursor--;
371 t_con->state = TELNET_STATE_DATA;
373 else if (*buf_p == CTRL('F')) /* cursor right */
375 if (t_con->line_cursor < t_con->line_size)
377 telnet_write(connection, t_con->line + t_con->line_cursor++, 1);
379 t_con->state = TELNET_STATE_DATA;
383 DEBUG("unhandled nonprintable: %2.2x", *buf_p);
388 case TELNET_STATE_IAC:
392 t_con->state = TELNET_STATE_DONT;
395 t_con->state = TELNET_STATE_DO;
398 t_con->state = TELNET_STATE_WONT;
401 t_con->state = TELNET_STATE_WILL;
405 case TELNET_STATE_SB:
407 case TELNET_STATE_SE:
409 case TELNET_STATE_WILL:
410 case TELNET_STATE_WONT:
411 case TELNET_STATE_DO:
412 case TELNET_STATE_DONT:
413 t_con->state = TELNET_STATE_DATA;
415 case TELNET_STATE_ESCAPE:
416 if (t_con->last_escape == '[')
418 if (*buf_p == 'D') /* cursor left */
420 if (t_con->line_cursor > 0)
422 telnet_write(connection, "\b", 1);
423 t_con->line_cursor--;
425 t_con->state = TELNET_STATE_DATA;
427 else if (*buf_p == 'C') /* cursor right */
429 if (t_con->line_cursor < t_con->line_size)
431 telnet_write(connection, t_con->line + t_con->line_cursor++, 1);
433 t_con->state = TELNET_STATE_DATA;
435 else if (*buf_p == 'A') /* cursor up */
437 int last_history = (t_con->current_history > 0) ? t_con->current_history - 1 : TELNET_LINE_HISTORY_SIZE-1;
438 if (t_con->history[last_history])
440 telnet_clear_line(connection, t_con);
441 t_con->line_size = strlen(t_con->history[last_history]);
442 t_con->line_cursor = t_con->line_size;
443 memcpy(t_con->line, t_con->history[last_history], t_con->line_size + 1);
444 telnet_write(connection, t_con->line, t_con->line_size);
445 t_con->current_history = last_history;
447 t_con->state = TELNET_STATE_DATA;
449 else if (*buf_p == 'B') /* cursor down */
451 int next_history = (t_con->current_history + 1) % TELNET_LINE_HISTORY_SIZE;
452 if (t_con->history[next_history])
454 telnet_clear_line(connection, t_con);
455 t_con->line_size = strlen(t_con->history[next_history]);
456 t_con->line_cursor = t_con->line_size;
457 memcpy(t_con->line, t_con->history[next_history], t_con->line_size + 1);
458 telnet_write(connection, t_con->line, t_con->line_size);
459 t_con->current_history = next_history;
461 t_con->state = TELNET_STATE_DATA;
463 else if (*buf_p == '3')
465 t_con->last_escape = *buf_p;
469 t_con->state = TELNET_STATE_DATA;
472 else if (t_con->last_escape == '3')
474 /* Remove character */
477 if (t_con->line_cursor < t_con->line_size)
481 /* remove char from line buffer */
482 memmove(t_con->line + t_con->line_cursor, t_con->line + t_con->line_cursor + 1, t_con->line_size - t_con->line_cursor);
484 /* print remainder of buffer */
485 telnet_write(connection, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor);
486 /* overwrite last char with whitespace */
487 telnet_write(connection, " \b", 2);
489 /* move back to cursor position*/
490 for (i = t_con->line_cursor; i < t_con->line_size; i++)
492 telnet_write(connection, "\b", 1);
496 t_con->state = TELNET_STATE_DATA;
500 t_con->state = TELNET_STATE_DATA;
503 else if (t_con->last_escape == '\x00')
507 t_con->last_escape = *buf_p;
511 t_con->state = TELNET_STATE_DATA;
516 ERROR("BUG: unexpected value in t_con->last_escape");
517 t_con->state = TELNET_STATE_DATA;
522 ERROR("unknown telnet state");
533 int telnet_connection_closed(connection_t *connection)
535 telnet_connection_t *t_con = connection->priv;
538 log_remove_callback(telnet_log_callback, connection);
543 t_con->prompt = NULL;
546 for (i = 0; i < TELNET_LINE_HISTORY_SIZE; i++)
548 if (t_con->history[i])
550 free(t_con->history[i]);
551 t_con->history[i] = NULL;
555 /* if this connection registered a debug-message receiver delete it */
556 delete_debug_msg_receiver(connection->cmd_ctx, NULL);
558 if (connection->priv)
560 free(connection->priv);
561 connection->priv = NULL;
565 ERROR("BUG: connection->priv == NULL");
568 target_unregister_event_callback(telnet_target_callback_event_handler, connection->cmd_ctx);
573 int telnet_set_prompt(connection_t *connection, char *prompt)
575 telnet_connection_t *t_con = connection->priv;
577 t_con->prompt = strdup(prompt);
582 int telnet_init(char *banner)
584 telnet_service_t *telnet_service = malloc(sizeof(telnet_service_t));
586 if (telnet_port == 0)
588 WARNING("no telnet port specified, using default port 4444");
592 telnet_service->banner = banner;
594 add_service("telnet", CONNECTION_TELNET, telnet_port, 1, telnet_new_connection, telnet_input, telnet_connection_closed, telnet_service);
599 int telnet_register_commands(command_context_t *command_context)
601 register_command(command_context, NULL, "exit", handle_exit_command,
602 COMMAND_EXEC, "exit telnet session");
604 register_command(command_context, NULL, "telnet_port", handle_telnet_port_command,
610 /* daemon configuration command telnet_port */
611 int handle_telnet_port_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc)
616 telnet_port = strtoul(args[0], NULL, 0);
621 int handle_exit_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc)
623 return ERROR_COMMAND_CLOSE_CONNECTION;