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   1 /***************************************************************************
   2  *   Copyright (C) 2005 by Dominic Rath                                    *
   3  *   Dominic.Rath@gmx.de                                                   *
   4  *                                                                         *
   5  *   Copyright (C) 2007-2010 Øyvind Harboe                                 *
   6  *   oyvind.harboe@zylin.com                                               *
   7  *                                                                         *
   8  *   Copyright (C) 2008 by Spencer Oliver                                  *
   9  *   spen@spen-soft.co.uk                                                  *
  10  *                                                                         *
  11  *   This program is free software; you can redistribute it and/or modify  *
  12  *   it under the terms of the GNU General Public License as published by  *
  13  *   the Free Software Foundation; either version 2 of the License, or     *
  14  *   (at your option) any later version.                                   *
  15  *                                                                         *
  16  *   This program is distributed in the hope that it will be useful,       *
  17  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
  18  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
  19  *   GNU General Public License for more details.                          *
  20  *                                                                         *
  21  *   You should have received a copy of the GNU General Public License     *
  22  *   along with this program.  If not, see <http://www.gnu.org/licenses/>. *
  23  ***************************************************************************/
  24
  25 #ifdef HAVE_CONFIG_H
  26 #include "config.h"
  27 #endif
  28
  29 #include "telnet_server.h"
  30 #include <target/target_request.h>
  31 #include <helper/configuration.h>
  32
  33 static char *telnet_port;
  34
  35 static char *negotiate =
  36         "\xFF\xFB\x03"                  /* IAC WILL Suppress Go Ahead */
  37         "\xFF\xFB\x01"                  /* IAC WILL Echo */
  38         "\xFF\xFD\x03"                  /* IAC DO Suppress Go Ahead */
  39         "\xFF\xFE\x01";                 /* IAC DON'T Echo */
  40
  41 #define CTRL(c) (c - '@')
  42 #define TELNET_HISTORY  ".openocd_history"
  43
  44 /* The only way we can detect that the socket is closed is the first time
  45  * we write to it, we will fail. Subsequent write operations will
  46  * succeed. Shudder!
  47  */
  48 static int telnet_write(struct connection *connection, const void *data,
  49         int len)
  50 {
  51         struct telnet_connection *t_con = connection->priv;
  52         if (t_con->closed)
  53                 return ERROR_SERVER_REMOTE_CLOSED;
  54
  55         if (connection_write(connection, data, len) == len)
  56                 return ERROR_OK;
  57         t_con->closed = 1;
  58         return ERROR_SERVER_REMOTE_CLOSED;
  59 }
  60
  61 static int telnet_prompt(struct connection *connection)
  62 {
  63         struct telnet_connection *t_con = connection->priv;
  64
  65         return telnet_write(connection, t_con->prompt, strlen(t_con->prompt));
  66 }
  67
  68 static int telnet_outputline(struct connection *connection, const char *line)
  69 {
  70         int len;
  71
  72         /* process lines in buffer */
  73         while (*line) {
  74                 char *line_end = strchr(line, '\n');
  75
  76                 if (line_end)
  77                         len = line_end-line;
  78                 else
  79                         len = strlen(line);
  80
  81                 telnet_write(connection, line, len);
  82                 if (line_end) {
  83                         telnet_write(connection, "\r\n", 2);
  84                         line += len + 1;
  85                 } else
  86                         line += len;
  87         }
  88
  89         return ERROR_OK;
  90 }
  91
  92 static int telnet_output(struct command_context *cmd_ctx, const char *line)
  93 {
  94         struct connection *connection = cmd_ctx->output_handler_priv;
  95
  96         return telnet_outputline(connection, line);
  97 }
  98
  99 static void telnet_log_callback(void *priv, const char *file, unsigned line,
 100         const char *function, const char *string)
 101 {
 102         struct connection *connection = priv;
 103         struct telnet_connection *t_con = connection->priv;
 104         int i;
 105
 106         /* if there is no prompt, simply output the message */
 107         if (t_con->line_cursor < 0) {
 108                 telnet_outputline(connection, string);
 109                 return;
 110         }
 111
 112         /* clear the command line */
 113         for (i = strlen(t_con->prompt) + t_con->line_size; i > 0; i -= 16)
 114                 telnet_write(connection, "\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b", i > 16 ? 16 : i);
 115         for (i = strlen(t_con->prompt) + t_con->line_size; i > 0; i -= 16)
 116                 telnet_write(connection, "                ", i > 16 ? 16 : i);
 117         for (i = strlen(t_con->prompt) + t_con->line_size; i > 0; i -= 16)
 118                 telnet_write(connection, "\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b", i > 16 ? 16 : i);
 119
 120         /* output the message */
 121         telnet_outputline(connection, string);
 122
 123         /* put the command line to its previous state */
 124         telnet_prompt(connection);
 125         telnet_write(connection, t_con->line, t_con->line_size);
 126         for (i = t_con->line_size; i > t_con->line_cursor; i--)
 127                 telnet_write(connection, "\b", 1);
 128 }
 129
 130 static void telnet_load_history(struct telnet_connection *t_con)
 131 {
 132         FILE *histfp;
 133         char buffer[TELNET_BUFFER_SIZE];
 134         int i = 0;
 135
 136         char *history = get_home_dir(TELNET_HISTORY);
 137
 138         if (history == NULL) {
 139                 LOG_INFO("unable to get user home directory, telnet history will be disabled");
 140                 return;
 141         }
 142
 143         histfp = fopen(history, "rb");
 144
 145         if (histfp) {
 146
 147                 while (fgets(buffer, sizeof(buffer), histfp) != NULL) {
 148
 149                         char *p = strchr(buffer, '\n');
 150                         if (p)
 151                                 *p = '\0';
 152                         if (buffer[0] && i < TELNET_LINE_HISTORY_SIZE)
 153                                 t_con->history[i++] = strdup(buffer);
 154                 }
 155
 156                 t_con->next_history = i;
 157                 t_con->next_history %= TELNET_LINE_HISTORY_SIZE;
 158                 /* try to set to last entry - 1, that way we skip over any exit/shutdown cmds */
 159                 t_con->current_history = t_con->next_history > 0 ? i - 1 : 0;
 160                 fclose(histfp);
 161         }
 162
 163         free(history);
 164 }
 165
 166 static void telnet_save_history(struct telnet_connection *t_con)
 167 {
 168         FILE *histfp;
 169         int i;
 170         int num;
 171
 172         char *history = get_home_dir(TELNET_HISTORY);
 173
 174         if (history == NULL) {
 175                 LOG_INFO("unable to get user home directory, telnet history will be disabled");
 176                 return;
 177         }
 178
 179         histfp = fopen(history, "wb");
 180
 181         if (histfp) {
 182
 183                 num = TELNET_LINE_HISTORY_SIZE;
 184                 i = t_con->current_history + 1;
 185                 i %= TELNET_LINE_HISTORY_SIZE;
 186
 187                 while (t_con->history[i] == NULL && num > 0) {
 188                         i++;
 189                         i %= TELNET_LINE_HISTORY_SIZE;
 190                         num--;
 191                 }
 192
 193                 if (num > 0) {
 194                         for (; num > 0; num--) {
 195                                 fprintf(histfp, "%s\n", t_con->history[i]);
 196                                 i++;
 197                                 i %= TELNET_LINE_HISTORY_SIZE;
 198                         }
 199                 }
 200                 fclose(histfp);
 201         }
 202
 203         free(history);
 204 }
 205
 206 static int telnet_new_connection(struct connection *connection)
 207 {
 208         struct telnet_connection *telnet_connection;
 209         struct telnet_service *telnet_service = connection->service->priv;
 210         int i;
 211
 212         telnet_connection = malloc(sizeof(struct telnet_connection));
 213
 214         if (!telnet_connection) {
 215                 LOG_ERROR("Failed to allocate telnet connection.");
 216                 return ERROR_FAIL;
 217         }
 218
 219         connection->priv = telnet_connection;
 220
 221         /* initialize telnet connection information */
 222         telnet_connection->closed = 0;
 223         telnet_connection->line_size = 0;
 224         telnet_connection->line_cursor = 0;
 225         telnet_connection->option_size = 0;
 226         telnet_connection->prompt = strdup("> ");
 227         telnet_connection->state = TELNET_STATE_DATA;
 228
 229         /* output goes through telnet connection */
 230         command_set_output_handler(connection->cmd_ctx, telnet_output, connection);
 231
 232         /* negotiate telnet options */
 233         telnet_write(connection, negotiate, strlen(negotiate));
 234
 235         /* print connection banner */
 236         if (telnet_service->banner) {
 237                 telnet_write(connection, telnet_service->banner, strlen(telnet_service->banner));
 238                 telnet_write(connection, "\r\n", 2);
 239         }
 240
 241         /* the prompt is always placed at the line beginning */
 242         telnet_write(connection, "\r", 1);
 243         telnet_prompt(connection);
 244
 245         /* initialize history */
 246         for (i = 0; i < TELNET_LINE_HISTORY_SIZE; i++)
 247                 telnet_connection->history[i] = NULL;
 248         telnet_connection->next_history = 0;
 249         telnet_connection->current_history = 0;
 250         telnet_load_history(telnet_connection);
 251
 252         log_add_callback(telnet_log_callback, connection);
 253
 254         return ERROR_OK;
 255 }
 256
 257 static void telnet_clear_line(struct connection *connection,
 258         struct telnet_connection *t_con)
 259 {
 260         /* move to end of line */
 261         if (t_con->line_cursor < t_con->line_size)
 262                 telnet_write(connection,
 263                         t_con->line + t_con->line_cursor,
 264                         t_con->line_size - t_con->line_cursor);
 265
 266         /* backspace, overwrite with space, backspace */
 267         while (t_con->line_size > 0) {
 268                 telnet_write(connection, "\b \b", 3);
 269                 t_con->line_size--;
 270         }
 271         t_con->line_cursor = 0;
 272 }
 273
 274 static void telnet_history_go(struct connection *connection, int idx)
 275 {
 276         struct telnet_connection *t_con = connection->priv;
 277
 278         if (t_con->history[idx]) {
 279                 telnet_clear_line(connection, t_con);
 280                 t_con->line_size = strlen(t_con->history[idx]);
 281                 t_con->line_cursor = t_con->line_size;
 282                 memcpy(t_con->line, t_con->history[idx], t_con->line_size);
 283                 telnet_write(connection, t_con->line, t_con->line_size);
 284                 t_con->current_history = idx;
 285         }
 286         t_con->state = TELNET_STATE_DATA;
 287 }
 288
 289 static void telnet_history_up(struct connection *connection)
 290 {
 291         struct telnet_connection *t_con = connection->priv;
 292
 293         int last_history = (t_con->current_history > 0) ?
 294                                 t_con->current_history - 1 :
 295                                 TELNET_LINE_HISTORY_SIZE-1;
 296         telnet_history_go(connection, last_history);
 297 }
 298
 299 static void telnet_history_down(struct connection *connection)
 300 {
 301         struct telnet_connection *t_con = connection->priv;
 302
 303         int next_history = (t_con->current_history + 1) % TELNET_LINE_HISTORY_SIZE;
 304         telnet_history_go(connection, next_history);
 305 }
 306
 307 static int telnet_input(struct connection *connection)
 308 {
 309         int bytes_read;
 310         unsigned char buffer[TELNET_BUFFER_SIZE];
 311         unsigned char *buf_p;
 312         struct telnet_connection *t_con = connection->priv;
 313         struct command_context *command_context = connection->cmd_ctx;
 314
 315         bytes_read = connection_read(connection, buffer, TELNET_BUFFER_SIZE);
 316
 317         if (bytes_read == 0)
 318                 return ERROR_SERVER_REMOTE_CLOSED;
 319         else if (bytes_read == -1) {
 320                 LOG_ERROR("error during read: %s", strerror(errno));
 321                 return ERROR_SERVER_REMOTE_CLOSED;
 322         }
 323
 324         buf_p = buffer;
 325         while (bytes_read) {
 326                 switch (t_con->state) {
 327                         case TELNET_STATE_DATA:
 328                                 if (*buf_p == 0xff)
 329                                         t_con->state = TELNET_STATE_IAC;
 330                                 else {
 331                                         if (isprint(*buf_p)) {  /* printable character */
 332                                                 /* watch buffer size leaving one spare character for
 333                                                  * string null termination */
 334                                                 if (t_con->line_size == TELNET_LINE_MAX_SIZE-1) {
 335                                                         /* output audible bell if buffer is full
 336                                                          * "\a" does not work, at least on windows */
 337                                                         telnet_write(connection, "\x07", 1);
 338                                                 } else if (t_con->line_cursor == t_con->line_size) {
 339                                                         telnet_write(connection, buf_p, 1);
 340                                                         t_con->line[t_con->line_size++] = *buf_p;
 341                                                         t_con->line_cursor++;
 342                                                 } else {
 343                                                         int i;
 344                                                         memmove(t_con->line + t_con->line_cursor + 1,
 345                                                                         t_con->line + t_con->line_cursor,
 346                                                                         t_con->line_size - t_con->line_cursor);
 347                                                         t_con->line[t_con->line_cursor] = *buf_p;
 348                                                         t_con->line_size++;
 349                                                         telnet_write(connection,
 350                                                                         t_con->line + t_con->line_cursor,
 351                                                                         t_con->line_size - t_con->line_cursor);
 352                                                         t_con->line_cursor++;
 353                                                         for (i = t_con->line_cursor; i < t_con->line_size; i++)
 354                                                                 telnet_write(connection, "\b", 1);
 355                                                 }
 356                                         } else {        /* non-printable */
 357                                                 if (*buf_p == 0x1b) {   /* escape */
 358                                                         t_con->state = TELNET_STATE_ESCAPE;
 359                                                         t_con->last_escape = '\x00';
 360                                                 } else if ((*buf_p == 0xd) || (*buf_p == 0xa)) {        /* CR/LF */
 361                                                         int retval;
 362
 363                                                         /* skip over combinations with CR/LF and NUL characters */
 364                                                         if ((bytes_read > 1) && ((*(buf_p + 1) == 0xa) ||
 365                                                                         (*(buf_p + 1) == 0xd))) {
 366                                                                 buf_p++;
 367                                                                 bytes_read--;
 368                                                         }
 369                                                         if ((bytes_read > 1) && (*(buf_p + 1) == 0)) {
 370                                                                 buf_p++;
 371                                                                 bytes_read--;
 372                                                         }
 373                                                         t_con->line[t_con->line_size] = 0;
 374
 375                                                         telnet_write(connection, "\r\n\x00", 3);
 376
 377                                                         if (strcmp(t_con->line, "history") == 0) {
 378                                                                 int i;
 379                                                                 for (i = 1; i < TELNET_LINE_HISTORY_SIZE; i++) {
 380                                                                         /* the t_con->next_history line contains empty string
 381                                                                          * (unless NULL), thus it is not printed */
 382                                                                         char *history_line = t_con->history[(t_con->
 383                                                                                         next_history + i) %
 384                                                                                         TELNET_LINE_HISTORY_SIZE];
 385                                                                         if (history_line) {
 386                                                                                 telnet_write(connection, history_line,
 387                                                                                                 strlen(history_line));
 388                                                                                 telnet_write(connection, "\r\n\x00", 3);
 389                                                                         }
 390                                                                 }
 391                                                                 t_con->line_size = 0;
 392                                                                 t_con->line_cursor = 0;
 393                                                                 continue;
 394                                                         }
 395
 396                                                         /* save only non-blank not repeating lines in the history */
 397                                                         char *prev_line = t_con->history[(t_con->current_history > 0) ?
 398                                                                         t_con->current_history - 1 : TELNET_LINE_HISTORY_SIZE-1];
 399                                                         if (*t_con->line && (prev_line == NULL ||
 400                                                                         strcmp(t_con->line, prev_line))) {
 401                                                                 /* if the history slot is already taken, free it */
 402                                                                 if (t_con->history[t_con->next_history])
 403                                                                         free(t_con->history[t_con->next_history]);
 404
 405                                                                 /* add line to history */
 406                                                                 t_con->history[t_con->next_history] = strdup(t_con->line);
 407
 408                                                                 /* wrap history at TELNET_LINE_HISTORY_SIZE */
 409                                                                 t_con->next_history = (t_con->next_history + 1) %
 410                                                                                 TELNET_LINE_HISTORY_SIZE;
 411
 412                                                                 /* current history line starts at the new entry */
 413                                                                 t_con->current_history =
 414                                                                                 t_con->next_history;
 415
 416                                                                 if (t_con->history[t_con->current_history])
 417                                                                         free(t_con->history[t_con->current_history]);
 418                                                                 t_con->history[t_con->current_history] = strdup("");
 419                                                         }
 420
 421                                                         t_con->line_size = 0;
 422
 423                                                         /* to suppress prompt in log callback during command execution */
 424                                                         t_con->line_cursor = -1;
 425
 426                                                         if (strcmp(t_con->line, "shutdown") == 0)
 427                                                                 telnet_save_history(t_con);
 428
 429                                                         retval = command_run_line(command_context, t_con->line);
 430
 431                                                         t_con->line_cursor = 0;
 432
 433                                                         if (retval == ERROR_COMMAND_CLOSE_CONNECTION)
 434                                                                 return ERROR_SERVER_REMOTE_CLOSED;
 435
 436                                                         /* the prompt is always * placed at the line beginning */
 437                                                         telnet_write(connection, "\r", 1);
 438
 439                                                         retval = telnet_prompt(connection);
 440                                                         if (retval == ERROR_SERVER_REMOTE_CLOSED)
 441                                                                 return ERROR_SERVER_REMOTE_CLOSED;
 442
 443                                                 } else if ((*buf_p == 0x7f) || (*buf_p == 0x8)) {       /* delete character */
 444                                                         if (t_con->line_cursor > 0) {
 445                                                                 if (t_con->line_cursor != t_con->line_size) {
 446                                                                         int i;
 447                                                                         telnet_write(connection, "\b", 1);
 448                                                                         t_con->line_cursor--;
 449                                                                         t_con->line_size--;
 450                                                                         memmove(t_con->line + t_con->line_cursor,
 451                                                                                         t_con->line + t_con->line_cursor + 1,
 452                                                                                         t_con->line_size -
 453                                                                                         t_con->line_cursor);
 454
 455                                                                         telnet_write(connection,
 456                                                                                         t_con->line + t_con->line_cursor,
 457                                                                                         t_con->line_size -
 458                                                                                         t_con->line_cursor);
 459                                                                         telnet_write(connection, " \b", 2);
 460                                                                         for (i = t_con->line_cursor; i < t_con->line_size; i++)
 461                                                                                 telnet_write(connection, "\b", 1);
 462                                                                 } else {
 463                                                                         t_con->line_size--;
 464                                                                         t_con->line_cursor--;
 465                                                                         /* back space: move the 'printer' head one char
 466                                                                          * back, overwrite with space, move back again */
 467                                                                         telnet_write(connection, "\b \b", 3);
 468                                                                 }
 469                                                         }
 470                                                 } else if (*buf_p == 0x15) /* clear line */
 471                                                         telnet_clear_line(connection, t_con);
 472                                                 else if (*buf_p == CTRL('B')) { /* cursor left */
 473                                                         if (t_con->line_cursor > 0) {
 474                                                                 telnet_write(connection, "\b", 1);
 475                                                                 t_con->line_cursor--;
 476                                                         }
 477                                                         t_con->state = TELNET_STATE_DATA;
 478                                                 } else if (*buf_p == CTRL('F')) {       /* cursor right */
 479                                                         if (t_con->line_cursor < t_con->line_size)
 480                                                                 telnet_write(connection, t_con->line + t_con->line_cursor++, 1);
 481                                                         t_con->state = TELNET_STATE_DATA;
 482                                                 } else if (*buf_p == CTRL('P'))         /* cursor up */
 483                                                         telnet_history_up(connection);
 484                                                 else if (*buf_p == CTRL('N'))           /* cursor down */
 485                                                         telnet_history_down(connection);
 486                                                 else
 487                                                         LOG_DEBUG("unhandled nonprintable: %2.2x", *buf_p);
 488                                         }
 489                                 }
 490                                 break;
 491                         case TELNET_STATE_IAC:
 492                                 switch (*buf_p) {
 493                                 case 0xfe:
 494                                         t_con->state = TELNET_STATE_DONT;
 495                                         break;
 496                                 case 0xfd:
 497                                         t_con->state = TELNET_STATE_DO;
 498                                         break;
 499                                 case 0xfc:
 500                                         t_con->state = TELNET_STATE_WONT;
 501                                         break;
 502                                 case 0xfb:
 503                                         t_con->state = TELNET_STATE_WILL;
 504                                         break;
 505                                 }
 506                                 break;
 507                         case TELNET_STATE_SB:
 508                                 break;
 509                         case TELNET_STATE_SE:
 510                                 break;
 511                         case TELNET_STATE_WILL:
 512                         case TELNET_STATE_WONT:
 513                         case TELNET_STATE_DO:
 514                         case TELNET_STATE_DONT:
 515                                 t_con->state = TELNET_STATE_DATA;
 516                                 break;
 517                         case TELNET_STATE_ESCAPE:
 518                                 if (t_con->last_escape == '[') {
 519                                         if (*buf_p == 'D') {    /* cursor left */
 520                                                 if (t_con->line_cursor > 0) {
 521                                                         telnet_write(connection, "\b", 1);
 522                                                         t_con->line_cursor--;
 523                                                 }
 524                                                 t_con->state = TELNET_STATE_DATA;
 525                                         } else if (*buf_p == 'C') {     /* cursor right */
 526                                                 if (t_con->line_cursor < t_con->line_size)
 527                                                         telnet_write(connection,
 528                                                                         t_con->line + t_con->line_cursor++, 1);
 529                                                 t_con->state = TELNET_STATE_DATA;
 530                                         } else if (*buf_p == 'A') {     /* cursor up */
 531                                                 telnet_history_up(connection);
 532                                         } else if (*buf_p == 'B') {     /* cursor down */
 533                                                 telnet_history_down(connection);
 534                                         } else if (*buf_p == '3')
 535                                                 t_con->last_escape = *buf_p;
 536                                         else
 537                                                 t_con->state = TELNET_STATE_DATA;
 538                                 } else if (t_con->last_escape == '3') {
 539                                         /* Remove character */
 540                                         if (*buf_p == '~') {
 541                                                 if (t_con->line_cursor < t_con->line_size) {
 542                                                         int i;
 543                                                         t_con->line_size--;
 544                                                         /* remove char from line buffer */
 545                                                         memmove(t_con->line + t_con->line_cursor,
 546                                                                         t_con->line + t_con->line_cursor + 1,
 547                                                                         t_con->line_size - t_con->line_cursor);
 548
 549                                                         /* print remainder of buffer */
 550                                                         telnet_write(connection, t_con->line + t_con->line_cursor,
 551                                                                         t_con->line_size - t_con->line_cursor);
 552                                                         /* overwrite last char with whitespace */
 553                                                         telnet_write(connection, " \b", 2);
 554
 555                                                         /* move back to cursor position*/
 556                                                         for (i = t_con->line_cursor; i < t_con->line_size; i++)
 557                                                                 telnet_write(connection, "\b", 1);
 558                                                 }
 559
 560                                                 t_con->state = TELNET_STATE_DATA;
 561                                         } else
 562                                                 t_con->state = TELNET_STATE_DATA;
 563                                 } else if (t_con->last_escape == '\x00') {
 564                                         if (*buf_p == '[')
 565                                                 t_con->last_escape = *buf_p;
 566                                         else
 567                                                 t_con->state = TELNET_STATE_DATA;
 568                                 } else {
 569                                         LOG_ERROR("BUG: unexpected value in t_con->last_escape");
 570                                         t_con->state = TELNET_STATE_DATA;
 571                                 }
 572
 573                                 break;
 574                         default:
 575                                 LOG_ERROR("unknown telnet state");
 576                                 exit(-1);
 577                 }
 578
 579                 bytes_read--;
 580                 buf_p++;
 581         }
 582
 583         return ERROR_OK;
 584 }
 585
 586 static int telnet_connection_closed(struct connection *connection)
 587 {
 588         struct telnet_connection *t_con = connection->priv;
 589         int i;
 590
 591         log_remove_callback(telnet_log_callback, connection);
 592
 593         if (t_con->prompt) {
 594                 free(t_con->prompt);
 595                 t_con->prompt = NULL;
 596         }
 597
 598         /* save telnet history */
 599         telnet_save_history(t_con);
 600
 601         for (i = 0; i < TELNET_LINE_HISTORY_SIZE; i++) {
 602                 if (t_con->history[i]) {
 603                         free(t_con->history[i]);
 604                         t_con->history[i] = NULL;
 605                 }
 606         }
 607
 608         /* if this connection registered a debug-message receiver delete it */
 609         delete_debug_msg_receiver(connection->cmd_ctx, NULL);
 610
 611         if (connection->priv) {
 612                 free(connection->priv);
 613                 connection->priv = NULL;
 614         } else
 615                 LOG_ERROR("BUG: connection->priv == NULL");
 616
 617         return ERROR_OK;
 618 }
 619
 620 int telnet_init(char *banner)
 621 {
 622         if (strcmp(telnet_port, "disabled") == 0) {
 623                 LOG_INFO("telnet server disabled");
 624                 return ERROR_OK;
 625         }
 626
 627         struct telnet_service *telnet_service;
 628
 629         telnet_service = malloc(sizeof(struct telnet_service));
 630
 631         if (!telnet_service) {
 632                 LOG_ERROR("Failed to allocate telnet service.");
 633                 return ERROR_FAIL;
 634         }
 635
 636         telnet_service->banner = banner;
 637
 638         return add_service("telnet",
 639                 telnet_port,
 640                 CONNECTION_LIMIT_UNLIMITED,
 641                 telnet_new_connection,
 642                 telnet_input,
 643                 telnet_connection_closed,
 644                 telnet_service);
 645 }
 646
 647 /* daemon configuration command telnet_port */
 648 COMMAND_HANDLER(handle_telnet_port_command)
 649 {
 650         return CALL_COMMAND_HANDLER(server_pipe_command, &telnet_port);
 651 }
 652
 653 COMMAND_HANDLER(handle_exit_command)
 654 {
 655         return ERROR_COMMAND_CLOSE_CONNECTION;
 656 }
 657
 658 static const struct command_registration telnet_command_handlers[] = {
 659         {
 660                 .name = "exit",
 661                 .handler = handle_exit_command,
 662                 .mode = COMMAND_EXEC,
 663                 .usage = "",
 664                 .help = "exit telnet session",
 665         },
 666         {
 667                 .name = "telnet_port",
 668                 .handler = handle_telnet_port_command,
 669                 .mode = COMMAND_ANY,
 670                 .help = "Specify port on which to listen "
 671                         "for incoming telnet connections.  "
 672                         "Read help on 'gdb_port'.",
 673                 .usage = "[port_num]",
 674         },
 675         COMMAND_REGISTRATION_DONE
 676 };
 677
 678 int telnet_register_commands(struct command_context *cmd_ctx)
 679 {
 680         telnet_port = strdup("4444");
 681         return register_commands(cmd_ctx, NULL, telnet_command_handlers);
 682 }