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 telnet_write(connection, "\r", 1); /* the prompt is always placed at the line beginning */
76 return telnet_write(connection, t_con->prompt, strlen(t_con->prompt));
79 int telnet_outputline(connection_t *connection, const char *line)
83 /* process lines in buffer */
85 char *line_end = strchr(line, '\n');
92 telnet_write(connection, line, len);
95 telnet_write(connection, "\r\n\0", 3);
107 int telnet_output(struct command_context_s *cmd_ctx, char* line)
109 connection_t *connection = cmd_ctx->output_handler_priv;
111 return telnet_outputline(connection, line);
114 void telnet_log_callback(void *priv, const char *file, int line,
115 const char *function, const char *string)
117 connection_t *connection = priv;
118 telnet_connection_t *t_con = connection->priv;
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);
126 telnet_write(connection, "\r", 1);
127 telnet_outputline(connection, string);
129 /* put the command line to its previous state */
130 telnet_prompt(connection);
131 telnet_write(connection, t_con->line, t_con->line_size);
132 for (i=t_con->line_size; i>t_con->line_cursor; i--)
133 telnet_write(connection, "\b", 1);
136 int telnet_target_callback_event_handler(struct target_s *target, enum target_event event, void *priv)
140 case TARGET_EVENT_HALTED:
141 target_arch_state(target);
150 int telnet_new_connection(connection_t *connection)
152 telnet_connection_t *telnet_connection = malloc(sizeof(telnet_connection_t));
153 telnet_service_t *telnet_service = connection->service->priv;
156 connection->priv = telnet_connection;
158 /* initialize telnet connection information */
159 telnet_connection->closed = 0;
160 telnet_connection->line_size = 0;
161 telnet_connection->line_cursor = 0;
162 telnet_connection->option_size = 0;
163 telnet_connection->prompt = strdup("> ");
164 telnet_connection->state = TELNET_STATE_DATA;
166 /* output goes through telnet connection */
167 command_set_output_handler(connection->cmd_ctx, telnet_output, connection);
169 /* negotiate telnet options */
170 telnet_write(connection, negotiate, strlen(negotiate));
172 /* print connection banner */
173 if (telnet_service->banner)
175 telnet_write(connection, telnet_service->banner, strlen(telnet_service->banner));
176 telnet_write(connection, "\r\n\0", 3);
179 telnet_prompt(connection);
181 /* initialize history */
182 for (i = 0; i < TELNET_LINE_HISTORY_SIZE; i++)
184 telnet_connection->history[i] = NULL;
186 telnet_connection->next_history = 0;
187 telnet_connection->current_history = 0;
189 target_register_event_callback(telnet_target_callback_event_handler, connection->cmd_ctx);
191 log_add_callback(telnet_log_callback, connection);
198 void telnet_clear_line(connection_t *connection, telnet_connection_t *t_con)
200 /* move to end of line */
201 if (t_con->line_cursor < t_con->line_size)
203 telnet_write(connection, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor);
206 /* backspace, overwrite with space, backspace */
207 while (t_con->line_size > 0)
209 telnet_write(connection, "\b \b", 3);
212 t_con->line_cursor = 0;
215 int telnet_input(connection_t *connection)
218 char buffer[TELNET_BUFFER_SIZE];
220 telnet_connection_t *t_con = connection->priv;
221 command_context_t *command_context = connection->cmd_ctx;
223 bytes_read = read_socket(connection->fd, buffer, TELNET_BUFFER_SIZE);
226 return ERROR_SERVER_REMOTE_CLOSED;
227 else if (bytes_read == -1)
229 ERROR("error during read: %s", strerror(errno));
230 return ERROR_SERVER_REMOTE_CLOSED;
236 switch (t_con->state)
238 case TELNET_STATE_DATA:
239 if (*buf_p == '\xff')
241 t_con->state = TELNET_STATE_IAC;
245 if (isprint(*buf_p)) /* printable character */
247 telnet_write(connection, buf_p, 1);
248 if (t_con->line_cursor == t_con->line_size)
250 t_con->line[t_con->line_size++] = *buf_p;
251 t_con->line_cursor++;
256 memmove(t_con->line + t_con->line_cursor + 1, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor);
257 t_con->line[t_con->line_cursor++] = *buf_p;
259 telnet_write(connection, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor);
260 for (i = t_con->line_cursor; i < t_con->line_size; i++)
262 telnet_write(connection, "\b", 1);
266 else /* non-printable */
268 if (*buf_p == 0x1b) /* escape */
270 t_con->state = TELNET_STATE_ESCAPE;
271 t_con->last_escape = '\x00';
273 else if ((*buf_p == 0xd) || (*buf_p == 0xa)) /* CR/LF */
277 /* skip over combinations with CR/LF + NUL */
278 if (((*(buf_p + 1) == 0xa) || (*(buf_p + 1) == 0xd)) && (bytes_read > 1))
283 if ((*(buf_p + 1) == 0) && (bytes_read > 1))
288 t_con->line[t_con->line_size] = 0;
290 telnet_write(connection, "\r\n\x00", 3);
292 if (strcmp(t_con->line, "history") == 0)
295 for (i = 0; i < TELNET_LINE_HISTORY_SIZE; i++)
297 if (t_con->history[i])
299 telnet_write(connection, t_con->history[i], strlen(t_con->history[i]));
300 telnet_write(connection, "\r\n\x00", 3);
303 t_con->line_size = 0;
304 t_con->line_cursor = 0;
308 /* Save only non-blank lines in the history */
309 if (t_con->line_size > 0)
311 /* if the history slot is already taken, free it */
312 if (t_con->history[t_con->next_history])
314 free(t_con->history[t_con->next_history]);
317 /* add line to history */
318 t_con->history[t_con->next_history] = strdup(t_con->line);
320 /* wrap history at TELNET_LINE_HISTORY_SIZE */
321 t_con->next_history = (t_con->next_history + 1) % TELNET_LINE_HISTORY_SIZE;
323 /* current history line starts at the new entry */
324 t_con->current_history = t_con->next_history;
326 if (t_con->history[t_con->current_history])
328 free(t_con->history[t_con->current_history]);
330 t_con->history[t_con->current_history] = strdup("");
333 t_con->line_size = 0;
334 t_con->line_cursor = 0;
336 retval = command_run_line(command_context, t_con->line);
337 if (retval == ERROR_COMMAND_CLOSE_CONNECTION)
338 return ERROR_SERVER_REMOTE_CLOSED;
340 retval = telnet_prompt(connection);
341 if (retval == ERROR_SERVER_REMOTE_CLOSED)
342 return ERROR_SERVER_REMOTE_CLOSED;
345 else if ((*buf_p == 0x7f) || (*buf_p == 0x8)) /* delete character */
347 if (t_con->line_cursor > 0)
349 if (t_con->line_cursor != t_con->line_size)
352 telnet_write(connection, "\b", 1);
353 t_con->line_cursor--;
355 memmove(t_con->line + t_con->line_cursor, t_con->line + t_con->line_cursor + 1, t_con->line_size - t_con->line_cursor);
357 telnet_write(connection, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor);
358 telnet_write(connection, " \b", 2);
359 for (i = t_con->line_cursor; i < t_con->line_size; i++)
361 telnet_write(connection, "\b", 1);
367 t_con->line_cursor--;
368 /* back space: move the 'printer' head one char back, overwrite with space, move back again */
369 telnet_write(connection, "\b \b", 3);
373 else if (*buf_p == 0x15) /* clear line */
375 telnet_clear_line(connection, t_con);
377 else if (*buf_p == CTRL('B')) /* cursor left */
379 if (t_con->line_cursor > 0)
381 telnet_write(connection, "\b", 1);
382 t_con->line_cursor--;
384 t_con->state = TELNET_STATE_DATA;
386 else if (*buf_p == CTRL('F')) /* cursor right */
388 if (t_con->line_cursor < t_con->line_size)
390 telnet_write(connection, t_con->line + t_con->line_cursor++, 1);
392 t_con->state = TELNET_STATE_DATA;
396 DEBUG("unhandled nonprintable: %2.2x", *buf_p);
401 case TELNET_STATE_IAC:
405 t_con->state = TELNET_STATE_DONT;
408 t_con->state = TELNET_STATE_DO;
411 t_con->state = TELNET_STATE_WONT;
414 t_con->state = TELNET_STATE_WILL;
418 case TELNET_STATE_SB:
420 case TELNET_STATE_SE:
422 case TELNET_STATE_WILL:
423 case TELNET_STATE_WONT:
424 case TELNET_STATE_DO:
425 case TELNET_STATE_DONT:
426 t_con->state = TELNET_STATE_DATA;
428 case TELNET_STATE_ESCAPE:
429 if (t_con->last_escape == '[')
431 if (*buf_p == 'D') /* cursor left */
433 if (t_con->line_cursor > 0)
435 telnet_write(connection, "\b", 1);
436 t_con->line_cursor--;
438 t_con->state = TELNET_STATE_DATA;
440 else if (*buf_p == 'C') /* cursor right */
442 if (t_con->line_cursor < t_con->line_size)
444 telnet_write(connection, t_con->line + t_con->line_cursor++, 1);
446 t_con->state = TELNET_STATE_DATA;
448 else if (*buf_p == 'A') /* cursor up */
450 int last_history = (t_con->current_history > 0) ? t_con->current_history - 1 : TELNET_LINE_HISTORY_SIZE-1;
451 if (t_con->history[last_history])
453 telnet_clear_line(connection, t_con);
454 t_con->line_size = strlen(t_con->history[last_history]);
455 t_con->line_cursor = t_con->line_size;
456 memcpy(t_con->line, t_con->history[last_history], t_con->line_size + 1);
457 telnet_write(connection, t_con->line, t_con->line_size);
458 t_con->current_history = last_history;
460 t_con->state = TELNET_STATE_DATA;
462 else if (*buf_p == 'B') /* cursor down */
464 int next_history = (t_con->current_history + 1) % TELNET_LINE_HISTORY_SIZE;
465 if (t_con->history[next_history])
467 telnet_clear_line(connection, t_con);
468 t_con->line_size = strlen(t_con->history[next_history]);
469 t_con->line_cursor = t_con->line_size;
470 memcpy(t_con->line, t_con->history[next_history], t_con->line_size + 1);
471 telnet_write(connection, t_con->line, t_con->line_size);
472 t_con->current_history = next_history;
474 t_con->state = TELNET_STATE_DATA;
476 else if (*buf_p == '3')
478 t_con->last_escape = *buf_p;
482 t_con->state = TELNET_STATE_DATA;
485 else if (t_con->last_escape == '3')
487 /* Remove character */
490 if (t_con->line_cursor < t_con->line_size)
494 /* remove char from line buffer */
495 memmove(t_con->line + t_con->line_cursor, t_con->line + t_con->line_cursor + 1, t_con->line_size - t_con->line_cursor);
497 /* print remainder of buffer */
498 telnet_write(connection, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor);
499 /* overwrite last char with whitespace */
500 telnet_write(connection, " \b", 2);
502 /* move back to cursor position*/
503 for (i = t_con->line_cursor; i < t_con->line_size; i++)
505 telnet_write(connection, "\b", 1);
509 t_con->state = TELNET_STATE_DATA;
513 t_con->state = TELNET_STATE_DATA;
516 else if (t_con->last_escape == '\x00')
520 t_con->last_escape = *buf_p;
524 t_con->state = TELNET_STATE_DATA;
529 ERROR("BUG: unexpected value in t_con->last_escape");
530 t_con->state = TELNET_STATE_DATA;
535 ERROR("unknown telnet state");
546 int telnet_connection_closed(connection_t *connection)
548 telnet_connection_t *t_con = connection->priv;
551 log_remove_callback(telnet_log_callback, connection);
556 t_con->prompt = NULL;
559 for (i = 0; i < TELNET_LINE_HISTORY_SIZE; i++)
561 if (t_con->history[i])
563 free(t_con->history[i]);
564 t_con->history[i] = NULL;
568 /* if this connection registered a debug-message receiver delete it */
569 delete_debug_msg_receiver(connection->cmd_ctx, NULL);
571 if (connection->priv)
573 free(connection->priv);
574 connection->priv = NULL;
578 ERROR("BUG: connection->priv == NULL");
581 target_unregister_event_callback(telnet_target_callback_event_handler, connection->cmd_ctx);
586 int telnet_set_prompt(connection_t *connection, char *prompt)
588 telnet_connection_t *t_con = connection->priv;
590 if (t_con->prompt != NULL)
593 t_con->prompt = strdup(prompt);
598 int telnet_init(char *banner)
600 telnet_service_t *telnet_service = malloc(sizeof(telnet_service_t));
602 if (telnet_port == 0)
604 WARNING("no telnet port specified, using default port 4444");
608 telnet_service->banner = banner;
610 add_service("telnet", CONNECTION_TELNET, telnet_port, 1, telnet_new_connection, telnet_input, telnet_connection_closed, telnet_service);
615 int telnet_register_commands(command_context_t *command_context)
617 register_command(command_context, NULL, "exit", handle_exit_command,
618 COMMAND_EXEC, "exit telnet session");
620 register_command(command_context, NULL, "telnet_port", handle_telnet_port_command,
626 /* daemon configuration command telnet_port */
627 int handle_telnet_port_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc)
632 telnet_port = strtoul(args[0], NULL, 0);
637 int handle_exit_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc)
639 return ERROR_COMMAND_CLOSE_CONNECTION;