git.sur5r.net Git - openocd/blob - src/server/telnet_server.c

   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, write to the                         *
  23  *   Free Software Foundation, Inc.,                                       *
  24  *   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.           *
  25  ***************************************************************************/
  26
  27 #ifdef HAVE_CONFIG_H
  28 #include "config.h"
  29 #endif
  30
  31 #include "telnet_server.h"
  32 #include <target/target_request.h>
  33 #include <helper/configuration.h>
  34
  35 static const char *telnet_port;
  36
  37 static char *negotiate =
  38         "\xFF\xFB\x03"                  /* IAC WILL Suppress Go Ahead */
  39         "\xFF\xFB\x01"                  /* IAC WILL Echo */
  40         "\xFF\xFD\x03"                  /* IAC DO Suppress Go Ahead */
  41         "\xFF\xFE\x01";                 /* IAC DON'T Echo */
  42
  43 #define CTRL(c) (c - '@')
  44 #define TELNET_HISTORY  ".openocd_history"
  45
  46 /* The only way we can detect that the socket is closed is the first time
  47  * we write to it, we will fail. Subsequent write operations will
  48  * succeed. Shudder!
  49  */
  50 static int telnet_write(struct connection *connection, const void *data,
  51         int len)
  52 {
  53         struct telnet_connection *t_con = connection->priv;
  54         if (t_con->closed)
  55                 return ERROR_SERVER_REMOTE_CLOSED;
  56
  57         if (connection_write(connection, data, len) == len)
  58                 return ERROR_OK;
  59         t_con->closed = 1;
  60         return ERROR_SERVER_REMOTE_CLOSED;
  61 }
  62
  63 static int telnet_prompt(struct connection *connection)
  64 {
  65         struct telnet_connection *t_con = connection->priv;
  66
  67         return telnet_write(connection, t_con->prompt, strlen(t_con->prompt));
  68 }
  69
  70 static int telnet_outputline(struct connection *connection, const char *line)
  71 {
  72         int len;
  73
  74         /* process lines in buffer */
  75         while (*line) {
  76                 char *line_end = strchr(line, '\n');
  77
  78                 if (line_end)
  79                         len = line_end-line;
  80                 else
  81                         len = strlen(line);
  82
  83                 telnet_write(connection, line, len);
  84                 if (line_end) {
  85                         telnet_write(connection, "\r\n", 2);
  86                         line += len + 1;
  87                 } else
  88                         line += len;
  89         }
  90
  91         return ERROR_OK;
  92 }
  93
  94 static int telnet_output(struct command_context *cmd_ctx, const char *line)
  95 {
  96         struct connection *connection = cmd_ctx->output_handler_priv;
  97
  98         return telnet_outputline(connection, line);
  99 }
 100
 101 static void telnet_log_callback(void *priv, const char *file, unsigned line,
 102         const char *function, const char *string)
 103 {
 104         struct connection *connection = priv;
 105         struct telnet_connection *t_con = connection->priv;
 106         int i;
 107
 108         /* if there is no prompt, simply output the message */
 109         if (t_con->line_cursor < 0) {
 110                 telnet_outputline(connection, string);
 111                 return;
 112         }
 113
 114         /* clear the command line */
 115         for (i = strlen(t_con->prompt) + t_con->line_size; i > 0; i -= 16)
 116                 telnet_write(connection, "\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b", i > 16 ? 16 : i);
 117         for (i = strlen(t_con->prompt) + t_con->line_size; i > 0; i -= 16)
 118                 telnet_write(connection, "                ", i > 16 ? 16 : i);
 119         for (i = strlen(t_con->prompt) + t_con->line_size; i > 0; i -= 16)
 120                 telnet_write(connection, "\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b", i > 16 ? 16 : i);
 121
 122         /* output the message */
 123         telnet_outputline(connection, string);
 124
 125         /* put the command line to its previous state */
 126         telnet_prompt(connection);
 127         telnet_write(connection, t_con->line, t_con->line_size);
 128         for (i = t_con->line_size; i > t_con->line_cursor; i--)
 129                 telnet_write(connection, "\b", 1);
 130 }
 131
 132 static void telnet_load_history(struct telnet_connection *t_con)
 133 {
 134         FILE *histfp;
 135         char buffer[TELNET_BUFFER_SIZE];
 136         int i = 0;
 137
 138         char *history = get_home_dir(TELNET_HISTORY);
 139
 140         if (history == NULL) {
 141                 LOG_INFO("unable to get user home directory, telnet history will be disabled");
 142                 return;
 143         }
 144
 145         histfp = fopen(history, "rb");
 146
 147         if (histfp) {
 148
 149                 while (fgets(buffer, sizeof(buffer), histfp) != NULL) {
 150
 151                         char *p = strchr(buffer, '\n');
 152                         if (p)
 153                                 *p = '\0';
 154                         if (buffer[0] && i < TELNET_LINE_HISTORY_SIZE)
 155                                 t_con->history[i++] = strdup(buffer);
 156                 }
 157
 158                 t_con->next_history = i;
 159                 t_con->next_history %= TELNET_LINE_HISTORY_SIZE;
 160                 /* try to set to last entry - 1, that way we skip over any exit/shutdown cmds */
 161                 t_con->current_history = t_con->next_history > 0 ? i - 1 : 0;
 162                 fclose(histfp);
 163         }
 164
 165         free(history);
 166 }
 167
 168 static void telnet_save_history(struct telnet_connection *t_con)
 169 {
 170         FILE *histfp;
 171         int i;
 172         int num;
 173
 174         char *history = get_home_dir(TELNET_HISTORY);
 175
 176         if (history == NULL) {
 177                 LOG_INFO("unable to get user home directory, telnet history will be disabled");
 178                 return;
 179         }
 180
 181         histfp = fopen(history, "wb");
 182
 183         if (histfp) {
 184
 185                 num = TELNET_LINE_HISTORY_SIZE;
 186                 i = t_con->current_history + 1;
 187                 i %= TELNET_LINE_HISTORY_SIZE;
 188
 189                 while (t_con->history[i] == NULL && num > 0) {
 190                         i++;
 191                         i %= TELNET_LINE_HISTORY_SIZE;
 192                         num--;
 193                 }
 194
 195                 if (num > 0) {
 196                         for (; num > 0; num--) {
 197                                 fprintf(histfp, "%s\n", t_con->history[i]);
 198                                 i++;
 199                                 i %= TELNET_LINE_HISTORY_SIZE;
 200                         }
 201                 }
 202                 fclose(histfp);
 203         }
 204
 205         free(history);
 206 }
 207
 208 static int telnet_new_connection(struct connection *connection)
 209 {
 210         struct telnet_connection *telnet_connection = malloc(sizeof(struct telnet_connection));
 211         struct telnet_service *telnet_service = connection->service->priv;
 212         int i;
 213
 214         connection->priv = telnet_connection;
 215
 216         /* initialize telnet connection information */
 217         telnet_connection->closed = 0;
 218         telnet_connection->line_size = 0;
 219         telnet_connection->line_cursor = 0;
 220         telnet_connection->option_size = 0;
 221         telnet_connection->prompt = strdup("> ");
 222         telnet_connection->state = TELNET_STATE_DATA;
 223
 224         /* output goes through telnet connection */
 225         command_set_output_handler(connection->cmd_ctx, telnet_output, connection);
 226
 227         /* negotiate telnet options */
 228         telnet_write(connection, negotiate, strlen(negotiate));
 229
 230         /* print connection banner */
 231         if (telnet_service->banner) {
 232                 telnet_write(connection, telnet_service->banner, strlen(telnet_service->banner));
 233                 telnet_write(connection, "\r\n", 2);
 234         }
 235
 236         /* the prompt is always placed at the line beginning */
 237         telnet_write(connection, "\r", 1);
 238         telnet_prompt(connection);
 239
 240         /* initialize history */
 241         for (i = 0; i < TELNET_LINE_HISTORY_SIZE; i++)
 242                 telnet_connection->history[i] = NULL;
 243         telnet_connection->next_history = 0;
 244         telnet_connection->current_history = 0;
 245         telnet_load_history(telnet_connection);
 246
 247         log_add_callback(telnet_log_callback, connection);
 248
 249         return ERROR_OK;
 250 }
 251
 252 static void telnet_clear_line(struct connection *connection,
 253         struct telnet_connection *t_con)
 254 {
 255         /* move to end of line */
 256         if (t_con->line_cursor < t_con->line_size)
 257                 telnet_write(connection,
 258                         t_con->line + t_con->line_cursor,
 259                         t_con->line_size - t_con->line_cursor);
 260
 261         /* backspace, overwrite with space, backspace */
 262         while (t_con->line_size > 0) {
 263                 telnet_write(connection, "\b \b", 3);
 264                 t_con->line_size--;
 265         }
 266         t_con->line_cursor = 0;
 267 }
 268
 269 static void telnet_history_go(struct connection *connection, int idx)
 270 {
 271         struct telnet_connection *t_con = connection->priv;
 272
 273         if (t_con->history[idx]) {
 274                 telnet_clear_line(connection, t_con);
 275                 t_con->line_size = strlen(t_con->history[idx]);
 276                 t_con->line_cursor = t_con->line_size;
 277                 memcpy(t_con->line, t_con->history[idx], t_con->line_size);
 278                 telnet_write(connection, t_con->line, t_con->line_size);
 279                 t_con->current_history = idx;
 280         }
 281         t_con->state = TELNET_STATE_DATA;
 282 }
 283
 284 static void telnet_history_up(struct connection *connection)
 285 {
 286         struct telnet_connection *t_con = connection->priv;
 287
 288         int last_history = (t_con->current_history > 0) ?
 289                                 t_con->current_history - 1 :
 290                                 TELNET_LINE_HISTORY_SIZE-1;
 291         telnet_history_go(connection, last_history);
 292 }
 293
 294 static void telnet_history_down(struct connection *connection)
 295 {
 296         struct telnet_connection *t_con = connection->priv;
 297
 298         int next_history = (t_con->current_history + 1) % TELNET_LINE_HISTORY_SIZE;
 299         telnet_history_go(connection, next_history);
 300 }
 301
 302 static int telnet_input(struct connection *connection)
 303 {
 304         int bytes_read;
 305         unsigned char buffer[TELNET_BUFFER_SIZE];
 306         unsigned char *buf_p;
 307         struct telnet_connection *t_con = connection->priv;
 308         struct command_context *command_context = connection->cmd_ctx;
 309
 310         bytes_read = connection_read(connection, buffer, TELNET_BUFFER_SIZE);
 311
 312         if (bytes_read == 0)
 313                 return ERROR_SERVER_REMOTE_CLOSED;
 314         else if (bytes_read == -1) {
 315                 LOG_ERROR("error during read: %s", strerror(errno));
 316                 return ERROR_SERVER_REMOTE_CLOSED;
 317         }
 318
 319         buf_p = buffer;
 320         while (bytes_read) {
 321                 switch (t_con->state) {
 322                         case TELNET_STATE_DATA:
 323                                 if (*buf_p == 0xff)
 324                                         t_con->state = TELNET_STATE_IAC;
 325                                 else {
 326                                         if (isprint(*buf_p)) {  /* printable character */
 327                                                 /* watch buffer size leaving one spare character for
 328                                                  * string null termination */
 329                                                 if (t_con->line_size == TELNET_LINE_MAX_SIZE-1) {
 330                                                         /* output audible bell if buffer is full
 331                                                          * "\a" does not work, at least on windows */
 332                                                         telnet_write(connection, "\x07", 1);
 333                                                 } else if (t_con->line_cursor == t_con->line_size) {
 334                                                         telnet_write(connection, buf_p, 1);
 335                                                         t_con->line[t_con->line_size++] = *buf_p;
 336                                                         t_con->line_cursor++;
 337                                                 } else {
 338                                                         int i;
 339                                                         memmove(t_con->line + t_con->line_cursor + 1,
 340                                                                         t_con->line + t_con->line_cursor,
 341                                                                         t_con->line_size - t_con->line_cursor);
 342                                                         t_con->line[t_con->line_cursor] = *buf_p;
 343                                                         t_con->line_size++;
 344                                                         telnet_write(connection,
 345                                                                         t_con->line + t_con->line_cursor,
 346                                                                         t_con->line_size - t_con->line_cursor);
 347                                                         t_con->line_cursor++;
 348                                                         for (i = t_con->line_cursor; i < t_con->line_size; i++)
 349                                                                 telnet_write(connection, "\b", 1);
 350                                                 }
 351                                         } else {        /* non-printable */
 352                                                 if (*buf_p == 0x1b) {   /* escape */
 353                                                         t_con->state = TELNET_STATE_ESCAPE;
 354                                                         t_con->last_escape = '\x00';
 355                                                 } else if ((*buf_p == 0xd) || (*buf_p == 0xa)) {        /* CR/LF */
 356                                                         int retval;
 357
 358                                                         /* skip over combinations with CR/LF and NUL characters */
 359                                                         if ((bytes_read > 1) && ((*(buf_p + 1) == 0xa) ||
 360                                                                         (*(buf_p + 1) == 0xd))) {
 361                                                                 buf_p++;
 362                                                                 bytes_read--;
 363                                                         }
 364                                                         if ((bytes_read > 1) && (*(buf_p + 1) == 0)) {
 365                                                                 buf_p++;
 366                                                                 bytes_read--;
 367                                                         }
 368                                                         t_con->line[t_con->line_size] = 0;
 369
 370                                                         telnet_write(connection, "\r\n\x00", 3);
 371
 372                                                         if (strcmp(t_con->line, "history") == 0) {
 373                                                                 int i;
 374                                                                 for (i = 1; i < TELNET_LINE_HISTORY_SIZE; i++) {
 375                                                                         /* the t_con->next_history line contains empty string
 376                                                                          * (unless NULL), thus it is not printed */
 377                                                                         char *history_line = t_con->history[(t_con->
 378                                                                                         next_history + i) %
 379                                                                                         TELNET_LINE_HISTORY_SIZE];
 380                                                                         if (history_line) {
 381                                                                                 telnet_write(connection, history_line,
 382                                                                                                 strlen(history_line));
 383                                                                                 telnet_write(connection, "\r\n\x00", 3);
 384                                                                         }
 385                                                                 }
 386                                                                 t_con->line_size = 0;
 387                                                                 t_con->line_cursor = 0;
 388                                                                 continue;
 389                                                         }
 390
 391                                                         /* save only non-blank not repeating lines in the history */
 392                                                         char *prev_line = t_con->history[(t_con->current_history > 0) ?
 393                                                                         t_con->current_history - 1 : TELNET_LINE_HISTORY_SIZE-1];
 394                                                         if (*t_con->line && (prev_line == NULL ||
 395                                                                         strcmp(t_con->line, prev_line))) {
 396                                                                 /* if the history slot is already taken, free it */
 397                                                                 if (t_con->history[t_con->next_history])
 398                                                                         free(t_con->history[t_con->next_history]);
 399
 400                                                                 /* add line to history */
 401                                                                 t_con->history[t_con->next_history] = strdup(t_con->line);
 402
 403                                                                 /* wrap history at TELNET_LINE_HISTORY_SIZE */
 404                                                                 t_con->next_history = (t_con->next_history + 1) %
 405                                                                                 TELNET_LINE_HISTORY_SIZE;
 406
 407                                                                 /* current history line starts at the new entry */
 408                                                                 t_con->current_history =
 409                                                                                 t_con->next_history;
 410
 411                                                                 if (t_con->history[t_con->current_history])
 412                                                                         free(t_con->history[t_con->current_history]);
 413                                                                 t_con->history[t_con->current_history] = strdup("");
 414                                                         }
 415
 416                                                         t_con->line_size = 0;
 417
 418                                                         /* to suppress prompt in log callback during command execution */
 419                                                         t_con->line_cursor = -1;
 420
 421                                                         if (strcmp(t_con->line, "shutdown") == 0)
 422                                                                 telnet_save_history(t_con);
 423
 424                                                         retval = command_run_line(command_context, t_con->line);
 425
 426                                                         t_con->line_cursor = 0;
 427
 428                                                         if (retval == ERROR_COMMAND_CLOSE_CONNECTION)
 429                                                                 return ERROR_SERVER_REMOTE_CLOSED;
 430
 431                                                         /* the prompt is always * placed at the line beginning */
 432                                                         telnet_write(connection, "\r", 1);
 433
 434                                                         retval = telnet_prompt(connection);
 435                                                         if (retval == ERROR_SERVER_REMOTE_CLOSED)
 436                                                                 return ERROR_SERVER_REMOTE_CLOSED;
 437
 438                                                 } else if ((*buf_p == 0x7f) || (*buf_p == 0x8)) {       /* delete character */
 439                                                         if (t_con->line_cursor > 0) {
 440                                                                 if (t_con->line_cursor != t_con->line_size) {
 441                                                                         int i;
 442                                                                         telnet_write(connection, "\b", 1);
 443                                                                         t_con->line_cursor--;
 444                                                                         t_con->line_size--;
 445                                                                         memmove(t_con->line + t_con->line_cursor,
 446                                                                                         t_con->line + t_con->line_cursor + 1,
 447                                                                                         t_con->line_size -
 448                                                                                         t_con->line_cursor);
 449
 450                                                                         telnet_write(connection,
 451                                                                                         t_con->line + t_con->line_cursor,
 452                                                                                         t_con->line_size -
 453                                                                                         t_con->line_cursor);
 454                                                                         telnet_write(connection, " \b", 2);
 455                                                                         for (i = t_con->line_cursor; i < t_con->line_size; i++)
 456                                                                                 telnet_write(connection, "\b", 1);
 457                                                                 } else {
 458                                                                         t_con->line_size--;
 459                                                                         t_con->line_cursor--;
 460                                                                         /* back space: move the 'printer' head one char
 461                                                                          * back, overwrite with space, move back again */
 462                                                                         telnet_write(connection, "\b \b", 3);
 463                                                                 }
 464                                                         }
 465                                                 } else if (*buf_p == 0x15) /* clear line */
 466                                                         telnet_clear_line(connection, t_con);
 467                                                 else if (*buf_p == CTRL('B')) { /* cursor left */
 468                                                         if (t_con->line_cursor > 0) {
 469                                                                 telnet_write(connection, "\b", 1);
 470                                                                 t_con->line_cursor--;
 471                                                         }
 472                                                         t_con->state = TELNET_STATE_DATA;
 473                                                 } else if (*buf_p == CTRL('F')) {       /* cursor right */
 474                                                         if (t_con->line_cursor < t_con->line_size)
 475                                                                 telnet_write(connection, t_con->line + t_con->line_cursor++, 1);
 476                                                         t_con->state = TELNET_STATE_DATA;
 477                                                 } else if (*buf_p == CTRL('P'))         /* cursor up */
 478                                                         telnet_history_up(connection);
 479                                                 else if (*buf_p == CTRL('N'))           /* cursor down */
 480                                                         telnet_history_down(connection);
 481                                                 else
 482                                                         LOG_DEBUG("unhandled nonprintable: %2.2x", *buf_p);
 483                                         }
 484                                 }
 485                                 break;
 486                         case TELNET_STATE_IAC:
 487                                 switch (*buf_p) {
 488                                 case 0xfe:
 489                                         t_con->state = TELNET_STATE_DONT;
 490                                         break;
 491                                 case 0xfd:
 492                                         t_con->state = TELNET_STATE_DO;
 493                                         break;
 494                                 case 0xfc:
 495                                         t_con->state = TELNET_STATE_WONT;
 496                                         break;
 497                                 case 0xfb:
 498                                         t_con->state = TELNET_STATE_WILL;
 499                                         break;
 500                                 }
 501                                 break;
 502                         case TELNET_STATE_SB:
 503                                 break;
 504                         case TELNET_STATE_SE:
 505                                 break;
 506                         case TELNET_STATE_WILL:
 507                         case TELNET_STATE_WONT:
 508                         case TELNET_STATE_DO:
 509                         case TELNET_STATE_DONT:
 510                                 t_con->state = TELNET_STATE_DATA;
 511                                 break;
 512                         case TELNET_STATE_ESCAPE:
 513                                 if (t_con->last_escape == '[') {
 514                                         if (*buf_p == 'D') {    /* cursor left */
 515                                                 if (t_con->line_cursor > 0) {
 516                                                         telnet_write(connection, "\b", 1);
 517                                                         t_con->line_cursor--;
 518                                                 }
 519                                                 t_con->state = TELNET_STATE_DATA;
 520                                         } else if (*buf_p == 'C') {     /* cursor right */
 521                                                 if (t_con->line_cursor < t_con->line_size)
 522                                                         telnet_write(connection,
 523                                                                         t_con->line + t_con->line_cursor++, 1);
 524                                                 t_con->state = TELNET_STATE_DATA;
 525                                         } else if (*buf_p == 'A') {     /* cursor up */
 526                                                 telnet_history_up(connection);
 527                                         } else if (*buf_p == 'B') {     /* cursor down */
 528                                                 telnet_history_down(connection);
 529                                         } else if (*buf_p == '3')
 530                                                 t_con->last_escape = *buf_p;
 531                                         else
 532                                                 t_con->state = TELNET_STATE_DATA;
 533                                 } else if (t_con->last_escape == '3') {
 534                                         /* Remove character */
 535                                         if (*buf_p == '~') {
 536                                                 if (t_con->line_cursor < t_con->line_size) {
 537                                                         int i;
 538                                                         t_con->line_size--;
 539                                                         /* remove char from line buffer */
 540                                                         memmove(t_con->line + t_con->line_cursor,
 541                                                                         t_con->line + t_con->line_cursor + 1,
 542                                                                         t_con->line_size - t_con->line_cursor);
 543
 544                                                         /* print remainder of buffer */
 545                                                         telnet_write(connection, t_con->line + t_con->line_cursor,
 546                                                                         t_con->line_size - t_con->line_cursor);
 547                                                         /* overwrite last char with whitespace */
 548                                                         telnet_write(connection, " \b", 2);
 549
 550                                                         /* move back to cursor position*/
 551                                                         for (i = t_con->line_cursor; i < t_con->line_size; i++)
 552                                                                 telnet_write(connection, "\b", 1);
 553                                                 }
 554
 555                                                 t_con->state = TELNET_STATE_DATA;
 556                                         } else
 557                                                 t_con->state = TELNET_STATE_DATA;
 558                                 } else if (t_con->last_escape == '\x00') {
 559                                         if (*buf_p == '[')
 560                                                 t_con->last_escape = *buf_p;
 561                                         else
 562                                                 t_con->state = TELNET_STATE_DATA;
 563                                 } else {
 564                                         LOG_ERROR("BUG: unexpected value in t_con->last_escape");
 565                                         t_con->state = TELNET_STATE_DATA;
 566                                 }
 567
 568                                 break;
 569                         default:
 570                                 LOG_ERROR("unknown telnet state");
 571                                 exit(-1);
 572                 }
 573
 574                 bytes_read--;
 575                 buf_p++;
 576         }
 577
 578         return ERROR_OK;
 579 }
 580
 581 static int telnet_connection_closed(struct connection *connection)
 582 {
 583         struct telnet_connection *t_con = connection->priv;
 584         int i;
 585
 586         log_remove_callback(telnet_log_callback, connection);
 587
 588         if (t_con->prompt) {
 589                 free(t_con->prompt);
 590                 t_con->prompt = NULL;
 591         }
 592
 593         /* save telnet history */
 594         telnet_save_history(t_con);
 595
 596         for (i = 0; i < TELNET_LINE_HISTORY_SIZE; i++) {
 597                 if (t_con->history[i]) {
 598                         free(t_con->history[i]);
 599                         t_con->history[i] = NULL;
 600                 }
 601         }
 602
 603         /* if this connection registered a debug-message receiver delete it */
 604         delete_debug_msg_receiver(connection->cmd_ctx, NULL);
 605
 606         if (connection->priv) {
 607                 free(connection->priv);
 608                 connection->priv = NULL;
 609         } else
 610                 LOG_ERROR("BUG: connection->priv == NULL");
 611
 612         return ERROR_OK;
 613 }
 614
 615 int telnet_init(char *banner)
 616 {
 617         if (strcmp(telnet_port, "disabled") == 0) {
 618                 LOG_INFO("telnet server disabled");
 619                 return ERROR_OK;
 620         }
 621
 622         struct telnet_service *telnet_service = malloc(sizeof(struct telnet_service));
 623
 624         telnet_service->banner = banner;
 625
 626         return add_service("telnet",
 627                 telnet_port,
 628                 1,
 629                 telnet_new_connection,
 630                 telnet_input,
 631                 telnet_connection_closed,
 632                 telnet_service);
 633 }
 634
 635 /* daemon configuration command telnet_port */
 636 COMMAND_HANDLER(handle_telnet_port_command)
 637 {
 638         return CALL_COMMAND_HANDLER(server_pipe_command, &telnet_port);
 639 }
 640
 641 COMMAND_HANDLER(handle_exit_command)
 642 {
 643         return ERROR_COMMAND_CLOSE_CONNECTION;
 644 }
 645
 646 static const struct command_registration telnet_command_handlers[] = {
 647         {
 648                 .name = "exit",
 649                 .handler = handle_exit_command,
 650                 .mode = COMMAND_EXEC,
 651                 .usage = "",
 652                 .help = "exit telnet session",
 653         },
 654         {
 655                 .name = "telnet_port",
 656                 .handler = handle_telnet_port_command,
 657                 .mode = COMMAND_ANY,
 658                 .help = "Specify port on which to listen "
 659                         "for incoming telnet connections.  "
 660                         "Read help on 'gdb_port'.",
 661                 .usage = "[port_num]",
 662         },
 663         COMMAND_REGISTRATION_DONE
 664 };
 665
 666 int telnet_register_commands(struct command_context *cmd_ctx)
 667 {
 668         telnet_port = strdup("4444");
 669         return register_commands(cmd_ctx, NULL, telnet_command_handlers);
 670 }