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   1 /***************************************************************************
   2  *   Copyright (C) 2005 by Dominic Rath                                    *
   3  *   Dominic.Rath@gmx.de                                                   *
   4  *                                                                         *
   5  *   Copyright (C) 2007,2008 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, 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 "replacements.h"
  31
  32 #include "telnet_server.h"
  33
  34 #include "server.h"
  35 #include "log.h"
  36 #include "command.h"
  37 #include "target.h"
  38 #include "target_request.h"
  39
  40 #include <stdlib.h>
  41 #include <unistd.h>
  42 #include <errno.h>
  43 #include <string.h>
  44 #include <ctype.h>
  45
  46 static unsigned short telnet_port = 0;
  47
  48 int handle_exit_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc);
  49 int handle_telnet_port_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc);
  50
  51 static char *negotiate =
  52                 "\xFF\xFB\x03"          /* IAC WILL Suppress Go Ahead */
  53                 "\xFF\xFB\x01"          /* IAC WILL Echo */
  54                 "\xFF\xFD\x03"          /* IAC DO Suppress Go Ahead */
  55                 "\xFF\xFE\x01";         /* IAC DON'T Echo */
  56
  57 #define CTRL(c) (c - '@')
  58
  59 /* The only way we can detect that the socket is closed is the first time
  60  * we write to it, we will fail. Subsequent write operations will
  61  * succeed. Shudder!
  62  */
  63 int telnet_write(connection_t *connection, const void *data, int len)
  64 {
  65         telnet_connection_t *t_con = connection->priv;
  66         if (t_con->closed)
  67                 return ERROR_SERVER_REMOTE_CLOSED;
  68
  69         if (write_socket(connection->fd, data, len) == len)
  70         {
  71                 return ERROR_OK;
  72         }
  73         t_con->closed = 1;
  74         return ERROR_SERVER_REMOTE_CLOSED;
  75 }
  76
  77 int telnet_prompt(connection_t *connection)
  78 {
  79         telnet_connection_t *t_con = connection->priv;
  80
  81         telnet_write(connection, "\r", 1); /* the prompt is always placed at the line beginning */
  82         return telnet_write(connection, t_con->prompt, strlen(t_con->prompt));
  83 }
  84
  85 int telnet_outputline(connection_t *connection, const char *line)
  86 {
  87         int len;
  88
  89         /* process lines in buffer */
  90         while (*line) {
  91                 char *line_end = strchr(line, '\n');
  92
  93                 if (line_end)
  94                         len = line_end-line;
  95                 else
  96                         len = strlen(line);
  97
  98                 telnet_write(connection, line, len);
  99                 if (line_end)
 100                 {
 101                         telnet_write(connection, "\r\n", 2);
 102                         line += len+1;
 103                 }
 104                 else
 105                 {
 106                         line += len;
 107                 }
 108         }
 109
 110         return ERROR_OK;
 111 }
 112
 113 int telnet_output(struct command_context_s *cmd_ctx, const char* line)
 114 {
 115         connection_t *connection = cmd_ctx->output_handler_priv;
 116
 117         return telnet_outputline(connection, line);
 118 }
 119
 120 void telnet_log_callback(void *priv, const char *file, int line,
 121                 const char *function, const char *string)
 122 {
 123         connection_t *connection = priv;
 124         telnet_connection_t *t_con = connection->priv;
 125         int i;
 126
 127         /* if there is no prompt, simply output the message */
 128         if (t_con->line_cursor < 0)
 129         {
 130                 telnet_outputline(connection, string);
 131                 return;
 132         }
 133
 134         /* clear the command line */
 135         telnet_write(connection, "\r", 1);
 136         for (i = strlen(t_con->prompt) + t_con->line_size; i>0; i-=16)
 137                 telnet_write(connection, "                ", i>16 ? 16 : i);
 138         telnet_write(connection, "\r", 1);
 139
 140         /* output the message */
 141         telnet_outputline(connection, string);
 142
 143         /* put the command line to its previous state */
 144         telnet_prompt(connection);
 145         telnet_write(connection, t_con->line, t_con->line_size);
 146         for (i=t_con->line_size; i>t_con->line_cursor; i--)
 147                 telnet_write(connection, "\b", 1);
 148 }
 149
 150 int telnet_new_connection(connection_t *connection)
 151 {
 152         telnet_connection_t *telnet_connection = malloc(sizeof(telnet_connection_t));
 153         telnet_service_t *telnet_service = connection->service->priv;
 154         int i;
 155
 156         connection->priv = telnet_connection;
 157
 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;
 165
 166         /* output goes through telnet connection */
 167         command_set_output_handler(connection->cmd_ctx, telnet_output, connection);
 168
 169         /* negotiate telnet options */
 170         telnet_write(connection, negotiate, strlen(negotiate));
 171
 172         /* print connection banner */
 173         if (telnet_service->banner)
 174         {
 175                 telnet_write(connection, telnet_service->banner, strlen(telnet_service->banner));
 176                 telnet_write(connection, "\r\n", 2);
 177         }
 178
 179         telnet_prompt(connection);
 180
 181         /* initialize history */
 182         for (i = 0; i < TELNET_LINE_HISTORY_SIZE; i++)
 183         {
 184                 telnet_connection->history[i] = NULL;
 185         }
 186         telnet_connection->next_history = 0;
 187         telnet_connection->current_history = 0;
 188
 189         log_add_callback(telnet_log_callback, connection);
 190
 191
 192
 193         return ERROR_OK;
 194 }
 195
 196 void telnet_clear_line(connection_t *connection, telnet_connection_t *t_con)
 197 {
 198         /* move to end of line */
 199         if (t_con->line_cursor < t_con->line_size)
 200         {
 201                 telnet_write(connection, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor);
 202         }
 203
 204         /* backspace, overwrite with space, backspace */
 205         while (t_con->line_size > 0)
 206         {
 207                 telnet_write(connection, "\b \b", 3);
 208                 t_con->line_size--;
 209         }
 210         t_con->line_cursor = 0;
 211 }
 212
 213 int telnet_input(connection_t *connection)
 214 {
 215         int bytes_read;
 216         char buffer[TELNET_BUFFER_SIZE];
 217         char *buf_p;
 218         telnet_connection_t *t_con = connection->priv;
 219         command_context_t *command_context = connection->cmd_ctx;
 220
 221         bytes_read = read_socket(connection->fd, buffer, TELNET_BUFFER_SIZE);
 222
 223         if (bytes_read == 0)
 224                 return ERROR_SERVER_REMOTE_CLOSED;
 225         else if (bytes_read == -1)
 226         {
 227                 LOG_ERROR("error during read: %s", strerror(errno));
 228                 return ERROR_SERVER_REMOTE_CLOSED;
 229         }
 230
 231         buf_p = buffer;
 232         while (bytes_read)
 233         {
 234                 switch (t_con->state)
 235                 {
 236                         case TELNET_STATE_DATA:
 237                                 if (*buf_p == '\xff')
 238                                 {
 239                                         t_con->state = TELNET_STATE_IAC;
 240                                 }
 241                                 else
 242                                 {
 243                                         if (isprint(*buf_p)) /* printable character */
 244                                         {
 245                                                 /* watch buffer size leaving one spare character for string null termination */
 246                                                 if (t_con->line_size == TELNET_LINE_MAX_SIZE-1)
 247                                                 {
 248                                                         /* output audible bell if buffer is full */
 249                                                         telnet_write(connection, "\x07", 1); /* "\a" does not work, at least on windows */
 250                                                 }
 251                                                 else if (t_con->line_cursor == t_con->line_size)
 252                                                 {
 253                                                         telnet_write(connection, buf_p, 1);
 254                                                         t_con->line[t_con->line_size++] = *buf_p;
 255                                                         t_con->line_cursor++;
 256                                                 }
 257                                                 else
 258                                                 {
 259                                                         int i;
 260                                                         memmove(t_con->line + t_con->line_cursor + 1, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor);
 261                                                         t_con->line[t_con->line_cursor] = *buf_p;
 262                                                         t_con->line_size++;
 263                                                         telnet_write(connection, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor);
 264                                                         t_con->line_cursor++;
 265                                                         for (i = t_con->line_cursor; i < t_con->line_size; i++)
 266                                                         {
 267                                                                 telnet_write(connection, "\b", 1);
 268                                                         }
 269                                                 }
 270                                         }
 271                                         else /* non-printable */
 272                                         {
 273                                                 if (*buf_p == 0x1b) /* escape */
 274                                                 {
 275                                                         t_con->state = TELNET_STATE_ESCAPE;
 276                                                         t_con->last_escape = '\x00';
 277                                                 }
 278                                                 else if ((*buf_p == 0xd) || (*buf_p == 0xa)) /* CR/LF */
 279                                                 {
 280                                                         int retval;
 281
 282                                                         /* skip over combinations with CR/LF and NUL characters */
 283                                                         if ((bytes_read > 1) && ((*(buf_p + 1) == 0xa) || (*(buf_p + 1) == 0xd)))
 284                                                         {
 285                                                                 buf_p++;
 286                                                                 bytes_read--;
 287                                                         }
 288                                                         if ((bytes_read > 1) && (*(buf_p + 1) == 0))
 289                                                         {
 290                                                                 buf_p++;
 291                                                                 bytes_read--;
 292                                                         }
 293                                                         t_con->line[t_con->line_size] = 0;
 294
 295                                                         telnet_write(connection, "\r\n\x00", 3);
 296
 297                                                         if (strcmp(t_con->line, "history") == 0)
 298                                                         {
 299                                                                 int i;
 300                                                                 for (i = 1; i < TELNET_LINE_HISTORY_SIZE; i++)
 301                                                                 {
 302                                                                         /* the t_con->next_history line contains empty string (unless NULL), thus it is not printed */
 303                                                                         char *history_line = t_con->history[(t_con->next_history + i) % TELNET_LINE_HISTORY_SIZE];
 304                                                                         if (history_line)
 305                                                                         {
 306                                                                                 telnet_write(connection, history_line, strlen(history_line));
 307                                                                                 telnet_write(connection, "\r\n\x00", 3);
 308                                                                         }
 309                                                                 }
 310                                                                 t_con->line_size = 0;
 311                                                                 t_con->line_cursor = 0;
 312                                                                 continue;
 313                                                         }
 314
 315                                                         /* save only non-blank not repeating lines in the history */
 316                                                         char *prev_line = t_con->history[(t_con->current_history > 0) ? t_con->current_history - 1 : TELNET_LINE_HISTORY_SIZE-1];
 317                                                         if (*t_con->line && (prev_line == NULL || strcmp(t_con->line, prev_line)))
 318                                                         {
 319                                                                 /* if the history slot is already taken, free it */
 320                                                                 if (t_con->history[t_con->next_history])
 321                                                                 {
 322                                                                         free(t_con->history[t_con->next_history]);
 323                                                                 }
 324
 325                                                                 /* add line to history */
 326                                                                 t_con->history[t_con->next_history] = strdup(t_con->line);
 327
 328                                                                 /* wrap history at TELNET_LINE_HISTORY_SIZE */
 329                                                                 t_con->next_history = (t_con->next_history + 1) % TELNET_LINE_HISTORY_SIZE;
 330
 331                                                                 /* current history line starts at the new entry */
 332                                                                 t_con->current_history = t_con->next_history;
 333
 334                                                                 if (t_con->history[t_con->current_history])
 335                                                                 {
 336                                                                         free(t_con->history[t_con->current_history]);
 337                                                                 }
 338                                                                 t_con->history[t_con->current_history] = strdup("");
 339                                                         }
 340
 341                                                         t_con->line_size = 0;
 342
 343                                                         t_con->line_cursor = -1; /* to supress prompt in log callback during command execution */
 344
 345                                                         retval = command_run_line(command_context, t_con->line);
 346
 347                                                         t_con->line_cursor = 0;
 348
 349                                                         if (retval == ERROR_COMMAND_CLOSE_CONNECTION)
 350                                                                 return ERROR_SERVER_REMOTE_CLOSED;
 351
 352                                                         retval = telnet_prompt(connection);
 353                                                         if (retval == ERROR_SERVER_REMOTE_CLOSED)
 354                                                                 return ERROR_SERVER_REMOTE_CLOSED;
 355
 356                                                 }
 357                                                 else if ((*buf_p == 0x7f) || (*buf_p == 0x8)) /* delete character */
 358                                                 {
 359                                                         if (t_con->line_cursor > 0)
 360                                                         {
 361                                                                 if (t_con->line_cursor != t_con->line_size)
 362                                                                 {
 363                                                                         int i;
 364                                                                         telnet_write(connection, "\b", 1);
 365                                                                         t_con->line_cursor--;
 366                                                                         t_con->line_size--;
 367                                                                         memmove(t_con->line + t_con->line_cursor, t_con->line + t_con->line_cursor + 1, t_con->line_size - t_con->line_cursor);
 368
 369                                                                         telnet_write(connection, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor);
 370                                                                         telnet_write(connection, " \b", 2);
 371                                                                         for (i = t_con->line_cursor; i < t_con->line_size; i++)
 372                                                                         {
 373                                                                                 telnet_write(connection, "\b", 1);
 374                                                                         }
 375                                                                 }
 376                                                                 else
 377                                                                 {
 378                                                                         t_con->line_size--;
 379                                                                         t_con->line_cursor--;
 380                                                                         /* back space: move the 'printer' head one char back, overwrite with space, move back again */
 381                                                                         telnet_write(connection, "\b \b", 3);
 382                                                                 }
 383                                                         }
 384                                                 }
 385                                                 else if (*buf_p == 0x15) /* clear line */
 386                                                 {
 387                                                         telnet_clear_line(connection, t_con);
 388                                                 }
 389                                                 else if (*buf_p == CTRL('B')) /* cursor left */
 390                                                 {
 391                                                         if (t_con->line_cursor > 0)
 392                                                         {
 393                                                                 telnet_write(connection, "\b", 1);
 394                                                                 t_con->line_cursor--;
 395                                                         }
 396                                                         t_con->state = TELNET_STATE_DATA;
 397                                                 }
 398                                                 else if (*buf_p == CTRL('F')) /* cursor right */
 399                                                 {
 400                                                         if (t_con->line_cursor < t_con->line_size)
 401                                                         {
 402                                                                 telnet_write(connection, t_con->line + t_con->line_cursor++, 1);
 403                                                         }
 404                                                         t_con->state = TELNET_STATE_DATA;
 405                                                 }
 406                                                 else
 407                                                 {
 408                                                         LOG_DEBUG("unhandled nonprintable: %2.2x", *buf_p);
 409                                                 }
 410                                         }
 411                                 }
 412                                 break;
 413                         case TELNET_STATE_IAC:
 414                                 switch (*buf_p)
 415                                 {
 416                                         case '\xfe':
 417                                                 t_con->state = TELNET_STATE_DONT;
 418                                                 break;
 419                                         case '\xfd':
 420                                                 t_con->state = TELNET_STATE_DO;
 421                                                 break;
 422                                         case '\xfc':
 423                                                 t_con->state = TELNET_STATE_WONT;
 424                                                 break;
 425                                         case '\xfb':
 426                                                 t_con->state = TELNET_STATE_WILL;
 427                                                 break;
 428                                 }
 429                                 break;
 430                         case TELNET_STATE_SB:
 431                                 break;
 432                         case TELNET_STATE_SE:
 433                                 break;
 434                         case TELNET_STATE_WILL:
 435                         case TELNET_STATE_WONT:
 436                         case TELNET_STATE_DO:
 437                         case TELNET_STATE_DONT:
 438                                 t_con->state = TELNET_STATE_DATA;
 439                                 break;
 440                         case TELNET_STATE_ESCAPE:
 441                                 if (t_con->last_escape == '[')
 442                                 {
 443                                         if (*buf_p == 'D') /* cursor left */
 444                                         {
 445                                                 if (t_con->line_cursor > 0)
 446                                                 {
 447                                                         telnet_write(connection, "\b", 1);
 448                                                         t_con->line_cursor--;
 449                                                 }
 450                                                 t_con->state = TELNET_STATE_DATA;
 451                                         }
 452                                         else if (*buf_p == 'C') /* cursor right */
 453                                         {
 454                                                 if (t_con->line_cursor < t_con->line_size)
 455                                                 {
 456                                                         telnet_write(connection, t_con->line + t_con->line_cursor++, 1);
 457                                                 }
 458                                                 t_con->state = TELNET_STATE_DATA;
 459                                         }
 460                                         else if (*buf_p == 'A') /* cursor up */
 461                                         {
 462                                                 int last_history = (t_con->current_history > 0) ? t_con->current_history - 1 : TELNET_LINE_HISTORY_SIZE-1;
 463                                                 if (t_con->history[last_history])
 464                                                 {
 465                                                         telnet_clear_line(connection, t_con);
 466                                                         t_con->line_size = strlen(t_con->history[last_history]);
 467                                                         t_con->line_cursor = t_con->line_size;
 468                                                         memcpy(t_con->line, t_con->history[last_history], t_con->line_size);
 469                                                         telnet_write(connection, t_con->line, t_con->line_size);
 470                                                         t_con->current_history = last_history;
 471                                                 }
 472                                                 t_con->state = TELNET_STATE_DATA;
 473                                         }
 474                                         else if (*buf_p == 'B') /* cursor down */
 475                                         {
 476                                                 int next_history = (t_con->current_history + 1) % TELNET_LINE_HISTORY_SIZE;
 477                                                 if (t_con->history[next_history])
 478                                                 {
 479                                                         telnet_clear_line(connection, t_con);
 480                                                         t_con->line_size = strlen(t_con->history[next_history]);
 481                                                         t_con->line_cursor = t_con->line_size;
 482                                                         memcpy(t_con->line, t_con->history[next_history], t_con->line_size);
 483                                                         telnet_write(connection, t_con->line, t_con->line_size);
 484                                                         t_con->current_history = next_history;
 485                                                 }
 486                                                 t_con->state = TELNET_STATE_DATA;
 487                                         }
 488                                         else if (*buf_p == '3')
 489                                         {
 490                                                 t_con->last_escape = *buf_p;
 491                                         }
 492                                         else
 493                                         {
 494                                                 t_con->state = TELNET_STATE_DATA;
 495                                         }
 496                                 }
 497                                 else if (t_con->last_escape == '3')
 498                                 {
 499                                         /* Remove character */
 500                                         if (*buf_p == '~')
 501                                         {
 502                                                 if (t_con->line_cursor < t_con->line_size)
 503                                                 {
 504                                                         int i;
 505                                                         t_con->line_size--;
 506                                                         /* remove char from line buffer */
 507                                                         memmove(t_con->line + t_con->line_cursor, t_con->line + t_con->line_cursor + 1, t_con->line_size - t_con->line_cursor);
 508
 509                                                         /* print remainder of buffer */
 510                                                         telnet_write(connection, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor);
 511                                                         /* overwrite last char with whitespace */
 512                                                         telnet_write(connection, " \b", 2);
 513
 514                                                         /* move back to cursor position*/
 515                                                         for (i = t_con->line_cursor; i < t_con->line_size; i++)
 516                                                         {
 517                                                                 telnet_write(connection, "\b", 1);
 518                                                         }
 519                                                 }
 520
 521                                                 t_con->state = TELNET_STATE_DATA;
 522                                         }
 523                                         else
 524                                         {
 525                                                 t_con->state = TELNET_STATE_DATA;
 526                                         }
 527                                 }
 528                                 else if (t_con->last_escape == '\x00')
 529                                 {
 530                                         if (*buf_p == '[')
 531                                         {
 532                                                 t_con->last_escape = *buf_p;
 533                                         }
 534                                         else
 535                                         {
 536                                                 t_con->state = TELNET_STATE_DATA;
 537                                         }
 538                                 }
 539                                 else
 540                                 {
 541                                         LOG_ERROR("BUG: unexpected value in t_con->last_escape");
 542                                         t_con->state = TELNET_STATE_DATA;
 543                                 }
 544
 545                                 break;
 546                         default:
 547                                 LOG_ERROR("unknown telnet state");
 548                                 exit(-1);
 549                 }
 550
 551                 bytes_read--;
 552                 buf_p++;
 553         }
 554
 555         return ERROR_OK;
 556 }
 557
 558 int telnet_connection_closed(connection_t *connection)
 559 {
 560         telnet_connection_t *t_con = connection->priv;
 561         int i;
 562
 563         log_remove_callback(telnet_log_callback, connection);
 564
 565         if (t_con->prompt)
 566         {
 567                 free(t_con->prompt);
 568                 t_con->prompt = NULL;
 569         }
 570
 571         for (i = 0; i < TELNET_LINE_HISTORY_SIZE; i++)
 572         {
 573                 if (t_con->history[i])
 574                 {
 575                         free(t_con->history[i]);
 576                         t_con->history[i] = NULL;
 577                 }
 578         }
 579
 580         /* if this connection registered a debug-message receiver delete it */
 581         delete_debug_msg_receiver(connection->cmd_ctx, NULL);
 582
 583         if (connection->priv)
 584         {
 585                 free(connection->priv);
 586                 connection->priv = NULL;
 587         }
 588         else
 589         {
 590                 LOG_ERROR("BUG: connection->priv == NULL");
 591         }
 592
 593         return ERROR_OK;
 594 }
 595
 596 int telnet_set_prompt(connection_t *connection, char *prompt)
 597 {
 598         telnet_connection_t *t_con = connection->priv;
 599
 600         if (t_con->prompt != NULL)
 601                 free(t_con->prompt);
 602
 603         t_con->prompt = strdup(prompt);
 604
 605         return ERROR_OK;
 606 }
 607
 608 int telnet_init(char *banner)
 609 {
 610         telnet_service_t *telnet_service = malloc(sizeof(telnet_service_t));
 611
 612         if (telnet_port == 0)
 613         {
 614                 LOG_WARNING("no telnet port specified, using default port 4444");
 615                 telnet_port = 4444;
 616         }
 617
 618         telnet_service->banner = banner;
 619
 620         add_service("telnet", CONNECTION_TELNET, telnet_port, 1, telnet_new_connection, telnet_input, telnet_connection_closed, telnet_service);
 621
 622         return ERROR_OK;
 623 }
 624
 625 int telnet_register_commands(command_context_t *command_context)
 626 {
 627         register_command(command_context, NULL, "exit", handle_exit_command,
 628                                          COMMAND_EXEC, "exit telnet session");
 629
 630         register_command(command_context, NULL, "telnet_port", handle_telnet_port_command,
 631                                          COMMAND_CONFIG, "port on which to listen for incoming telnet connections");
 632
 633         return ERROR_OK;
 634 }
 635
 636 /* daemon configuration command telnet_port */
 637 int handle_telnet_port_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc)
 638 {
 639         if (argc == 0)
 640         {
 641                 command_print(cmd_ctx, "%d", telnet_port);
 642                 return ERROR_OK;
 643         }
 644
 645         telnet_port = strtoul(args[0], NULL, 0);
 646
 647         return ERROR_OK;
 648 }
 649
 650 int handle_exit_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc)
 651 {
 652         return ERROR_COMMAND_CLOSE_CONNECTION;
 653 }