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  *   59 Temple Place - Suite 330, Boston, MA  02111-1307, 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 int telnet_input(struct connection *connection)
 270 {
 271         int bytes_read;
 272         unsigned char buffer[TELNET_BUFFER_SIZE];
 273         unsigned char *buf_p;
 274         struct telnet_connection *t_con = connection->priv;
 275         struct command_context *command_context = connection->cmd_ctx;
 276
 277         bytes_read = connection_read(connection, buffer, TELNET_BUFFER_SIZE);
 278
 279         if (bytes_read == 0)
 280                 return ERROR_SERVER_REMOTE_CLOSED;
 281         else if (bytes_read == -1) {
 282                 LOG_ERROR("error during read: %s", strerror(errno));
 283                 return ERROR_SERVER_REMOTE_CLOSED;
 284         }
 285
 286         buf_p = buffer;
 287         while (bytes_read) {
 288                 switch (t_con->state) {
 289                         case TELNET_STATE_DATA:
 290                                 if (*buf_p == 0xff)
 291                                         t_con->state = TELNET_STATE_IAC;
 292                                 else {
 293                                         if (isprint(*buf_p)) {  /* printable character */
 294                                                 /* watch buffer size leaving one spare character for
 295                                                  * string null termination */
 296                                                 if (t_con->line_size == TELNET_LINE_MAX_SIZE-1) {
 297                                                         /* output audible bell if buffer is full
 298                                                          * "\a" does not work, at least on windows */
 299                                                         telnet_write(connection, "\x07", 1);
 300                                                 } else if (t_con->line_cursor == t_con->line_size) {
 301                                                         telnet_write(connection, buf_p, 1);
 302                                                         t_con->line[t_con->line_size++] = *buf_p;
 303                                                         t_con->line_cursor++;
 304                                                 } else {
 305                                                         int i;
 306                                                         memmove(t_con->line + t_con->line_cursor + 1,
 307                                                                         t_con->line + t_con->line_cursor,
 308                                                                         t_con->line_size - t_con->line_cursor);
 309                                                         t_con->line[t_con->line_cursor] = *buf_p;
 310                                                         t_con->line_size++;
 311                                                         telnet_write(connection,
 312                                                                         t_con->line + t_con->line_cursor,
 313                                                                         t_con->line_size - t_con->line_cursor);
 314                                                         t_con->line_cursor++;
 315                                                         for (i = t_con->line_cursor; i < t_con->line_size; i++)
 316                                                                 telnet_write(connection, "\b", 1);
 317                                                 }
 318                                         } else {        /* non-printable */
 319                                                 if (*buf_p == 0x1b) {   /* escape */
 320                                                         t_con->state = TELNET_STATE_ESCAPE;
 321                                                         t_con->last_escape = '\x00';
 322                                                 } else if ((*buf_p == 0xd) || (*buf_p == 0xa)) {        /* CR/LF */
 323                                                         int retval;
 324
 325                                                         /* skip over combinations with CR/LF and NUL characters */
 326                                                         if ((bytes_read > 1) && ((*(buf_p + 1) == 0xa) ||
 327                                                                         (*(buf_p + 1) == 0xd))) {
 328                                                                 buf_p++;
 329                                                                 bytes_read--;
 330                                                         }
 331                                                         if ((bytes_read > 1) && (*(buf_p + 1) == 0)) {
 332                                                                 buf_p++;
 333                                                                 bytes_read--;
 334                                                         }
 335                                                         t_con->line[t_con->line_size] = 0;
 336
 337                                                         telnet_write(connection, "\r\n\x00", 3);
 338
 339                                                         if (strcmp(t_con->line, "history") == 0) {
 340                                                                 int i;
 341                                                                 for (i = 1; i < TELNET_LINE_HISTORY_SIZE; i++) {
 342                                                                         /* the t_con->next_history line contains empty string
 343                                                                          * (unless NULL), thus it is not printed */
 344                                                                         char *history_line = t_con->history[(t_con->
 345                                                                                         next_history + i) %
 346                                                                                         TELNET_LINE_HISTORY_SIZE];
 347                                                                         if (history_line) {
 348                                                                                 telnet_write(connection, history_line,
 349                                                                                                 strlen(history_line));
 350                                                                                 telnet_write(connection, "\r\n\x00", 3);
 351                                                                         }
 352                                                                 }
 353                                                                 t_con->line_size = 0;
 354                                                                 t_con->line_cursor = 0;
 355                                                                 continue;
 356                                                         }
 357
 358                                                         /* save only non-blank not repeating lines in the history */
 359                                                         char *prev_line = t_con->history[(t_con->current_history > 0) ?
 360                                                                         t_con->current_history - 1 : TELNET_LINE_HISTORY_SIZE-1];
 361                                                         if (*t_con->line && (prev_line == NULL ||
 362                                                                         strcmp(t_con->line, prev_line))) {
 363                                                                 /* if the history slot is already taken, free it */
 364                                                                 if (t_con->history[t_con->next_history])
 365                                                                         free(t_con->history[t_con->next_history]);
 366
 367                                                                 /* add line to history */
 368                                                                 t_con->history[t_con->next_history] = strdup(t_con->line);
 369
 370                                                                 /* wrap history at TELNET_LINE_HISTORY_SIZE */
 371                                                                 t_con->next_history = (t_con->next_history + 1) %
 372                                                                                 TELNET_LINE_HISTORY_SIZE;
 373
 374                                                                 /* current history line starts at the new entry */
 375                                                                 t_con->current_history =
 376                                                                                 t_con->next_history;
 377
 378                                                                 if (t_con->history[t_con->current_history])
 379                                                                         free(t_con->history[t_con->current_history]);
 380                                                                 t_con->history[t_con->current_history] = strdup("");
 381                                                         }
 382
 383                                                         t_con->line_size = 0;
 384
 385                                                         /* to suppress prompt in log callback during command execution */
 386                                                         t_con->line_cursor = -1;
 387
 388                                                         if (strcmp(t_con->line, "shutdown") == 0)
 389                                                                 telnet_save_history(t_con);
 390
 391                                                         retval = command_run_line(command_context, t_con->line);
 392
 393                                                         t_con->line_cursor = 0;
 394
 395                                                         if (retval == ERROR_COMMAND_CLOSE_CONNECTION)
 396                                                                 return ERROR_SERVER_REMOTE_CLOSED;
 397
 398                                                         /* the prompt is always * placed at the line beginning */
 399                                                         telnet_write(connection, "\r", 1);
 400
 401                                                         retval = telnet_prompt(connection);
 402                                                         if (retval == ERROR_SERVER_REMOTE_CLOSED)
 403                                                                 return ERROR_SERVER_REMOTE_CLOSED;
 404
 405                                                 } else if ((*buf_p == 0x7f) || (*buf_p == 0x8)) {       /* delete character */
 406                                                         if (t_con->line_cursor > 0) {
 407                                                                 if (t_con->line_cursor != t_con->line_size) {
 408                                                                         int i;
 409                                                                         telnet_write(connection, "\b", 1);
 410                                                                         t_con->line_cursor--;
 411                                                                         t_con->line_size--;
 412                                                                         memmove(t_con->line + t_con->line_cursor,
 413                                                                                         t_con->line + t_con->line_cursor + 1,
 414                                                                                         t_con->line_size -
 415                                                                                         t_con->line_cursor);
 416
 417                                                                         telnet_write(connection,
 418                                                                                         t_con->line + t_con->line_cursor,
 419                                                                                         t_con->line_size -
 420                                                                                         t_con->line_cursor);
 421                                                                         telnet_write(connection, " \b", 2);
 422                                                                         for (i = t_con->line_cursor; i < t_con->line_size; i++)
 423                                                                                 telnet_write(connection, "\b", 1);
 424                                                                 } else {
 425                                                                         t_con->line_size--;
 426                                                                         t_con->line_cursor--;
 427                                                                         /* back space: move the 'printer' head one char
 428                                                                          * back, overwrite with space, move back again */
 429                                                                         telnet_write(connection, "\b \b", 3);
 430                                                                 }
 431                                                         }
 432                                                 } else if (*buf_p == 0x15) /* clear line */
 433                                                         telnet_clear_line(connection, t_con);
 434                                                 else if (*buf_p == CTRL('B')) { /* cursor left */
 435                                                         if (t_con->line_cursor > 0) {
 436                                                                 telnet_write(connection, "\b", 1);
 437                                                                 t_con->line_cursor--;
 438                                                         }
 439                                                         t_con->state = TELNET_STATE_DATA;
 440                                                 } else if (*buf_p == CTRL('F')) {       /* cursor right */
 441                                                         if (t_con->line_cursor < t_con->line_size)
 442                                                                 telnet_write(connection, t_con->line + t_con->line_cursor++, 1);
 443                                                         t_con->state = TELNET_STATE_DATA;
 444                                                 } else
 445                                                         LOG_DEBUG("unhandled nonprintable: %2.2x", *buf_p);
 446                                         }
 447                                 }
 448                                 break;
 449                         case TELNET_STATE_IAC:
 450                                 switch (*buf_p) {
 451                                 case 0xfe:
 452                                         t_con->state = TELNET_STATE_DONT;
 453                                         break;
 454                                 case 0xfd:
 455                                         t_con->state = TELNET_STATE_DO;
 456                                         break;
 457                                 case 0xfc:
 458                                         t_con->state = TELNET_STATE_WONT;
 459                                         break;
 460                                 case 0xfb:
 461                                         t_con->state = TELNET_STATE_WILL;
 462                                         break;
 463                                 }
 464                                 break;
 465                         case TELNET_STATE_SB:
 466                                 break;
 467                         case TELNET_STATE_SE:
 468                                 break;
 469                         case TELNET_STATE_WILL:
 470                         case TELNET_STATE_WONT:
 471                         case TELNET_STATE_DO:
 472                         case TELNET_STATE_DONT:
 473                                 t_con->state = TELNET_STATE_DATA;
 474                                 break;
 475                         case TELNET_STATE_ESCAPE:
 476                                 if (t_con->last_escape == '[') {
 477                                         if (*buf_p == 'D') {    /* cursor left */
 478                                                 if (t_con->line_cursor > 0) {
 479                                                         telnet_write(connection, "\b", 1);
 480                                                         t_con->line_cursor--;
 481                                                 }
 482                                                 t_con->state = TELNET_STATE_DATA;
 483                                         } else if (*buf_p == 'C') {     /* cursor right */
 484                                                 if (t_con->line_cursor < t_con->line_size)
 485                                                         telnet_write(connection,
 486                                                                         t_con->line + t_con->line_cursor++, 1);
 487                                                 t_con->state = TELNET_STATE_DATA;
 488                                         } else if (*buf_p == 'A') {     /* cursor up */
 489                                                 int last_history = (t_con->current_history > 0) ?
 490                                                                 t_con->current_history - 1 : TELNET_LINE_HISTORY_SIZE-1;
 491                                                 if (t_con->history[last_history]) {
 492                                                         telnet_clear_line(connection, t_con);
 493                                                         t_con->line_size = strlen(t_con->history[last_history]);
 494                                                         t_con->line_cursor = t_con->line_size;
 495                                                         memcpy(t_con->line, t_con->history[last_history], t_con->line_size);
 496                                                         telnet_write(connection, t_con->line, t_con->line_size);
 497                                                         t_con->current_history = last_history;
 498                                                 }
 499                                                 t_con->state = TELNET_STATE_DATA;
 500                                         } else if (*buf_p == 'B') {     /* cursor down */
 501                                                 int next_history = (t_con->current_history + 1) % TELNET_LINE_HISTORY_SIZE;
 502                                                 if (t_con->history[next_history]) {
 503                                                         telnet_clear_line(connection, t_con);
 504                                                         t_con->line_size = strlen(t_con->history[next_history]);
 505                                                         t_con->line_cursor = t_con->line_size;
 506                                                         memcpy(t_con->line, t_con->history[next_history], t_con->line_size);
 507                                                         telnet_write(connection, t_con->line, t_con->line_size);
 508                                                         t_con->current_history = next_history;
 509                                                 }
 510                                                 t_con->state = TELNET_STATE_DATA;
 511                                         } else if (*buf_p == '3')
 512                                                 t_con->last_escape = *buf_p;
 513                                         else
 514                                                 t_con->state = TELNET_STATE_DATA;
 515                                 } else if (t_con->last_escape == '3') {
 516                                         /* Remove character */
 517                                         if (*buf_p == '~') {
 518                                                 if (t_con->line_cursor < t_con->line_size) {
 519                                                         int i;
 520                                                         t_con->line_size--;
 521                                                         /* remove char from line buffer */
 522                                                         memmove(t_con->line + t_con->line_cursor,
 523                                                                         t_con->line + t_con->line_cursor + 1,
 524                                                                         t_con->line_size - t_con->line_cursor);
 525
 526                                                         /* print remainder of buffer */
 527                                                         telnet_write(connection, t_con->line + t_con->line_cursor,
 528                                                                         t_con->line_size - t_con->line_cursor);
 529                                                         /* overwrite last char with whitespace */
 530                                                         telnet_write(connection, " \b", 2);
 531
 532                                                         /* move back to cursor position*/
 533                                                         for (i = t_con->line_cursor; i < t_con->line_size; i++)
 534                                                                 telnet_write(connection, "\b", 1);
 535                                                 }
 536
 537                                                 t_con->state = TELNET_STATE_DATA;
 538                                         } else
 539                                                 t_con->state = TELNET_STATE_DATA;
 540                                 } else if (t_con->last_escape == '\x00') {
 541                                         if (*buf_p == '[')
 542                                                 t_con->last_escape = *buf_p;
 543                                         else
 544                                                 t_con->state = TELNET_STATE_DATA;
 545                                 } else {
 546                                         LOG_ERROR("BUG: unexpected value in t_con->last_escape");
 547                                         t_con->state = TELNET_STATE_DATA;
 548                                 }
 549
 550                                 break;
 551                         default:
 552                                 LOG_ERROR("unknown telnet state");
 553                                 exit(-1);
 554                 }
 555
 556                 bytes_read--;
 557                 buf_p++;
 558         }
 559
 560         return ERROR_OK;
 561 }
 562
 563 static int telnet_connection_closed(struct connection *connection)
 564 {
 565         struct telnet_connection *t_con = connection->priv;
 566         int i;
 567
 568         log_remove_callback(telnet_log_callback, connection);
 569
 570         if (t_con->prompt) {
 571                 free(t_con->prompt);
 572                 t_con->prompt = NULL;
 573         }
 574
 575         /* save telnet history */
 576         telnet_save_history(t_con);
 577
 578         for (i = 0; i < TELNET_LINE_HISTORY_SIZE; i++) {
 579                 if (t_con->history[i]) {
 580                         free(t_con->history[i]);
 581                         t_con->history[i] = NULL;
 582                 }
 583         }
 584
 585         /* if this connection registered a debug-message receiver delete it */
 586         delete_debug_msg_receiver(connection->cmd_ctx, NULL);
 587
 588         if (connection->priv) {
 589                 free(connection->priv);
 590                 connection->priv = NULL;
 591         } else
 592                 LOG_ERROR("BUG: connection->priv == NULL");
 593
 594         return ERROR_OK;
 595 }
 596
 597 int telnet_init(char *banner)
 598 {
 599         if (strcmp(telnet_port, "disabled") == 0) {
 600                 LOG_INFO("telnet server disabled");
 601                 return ERROR_OK;
 602         }
 603
 604         struct telnet_service *telnet_service = malloc(sizeof(struct telnet_service));
 605
 606         telnet_service->banner = banner;
 607
 608         return add_service("telnet",
 609                 telnet_port,
 610                 1,
 611                 telnet_new_connection,
 612                 telnet_input,
 613                 telnet_connection_closed,
 614                 telnet_service);
 615 }
 616
 617 /* daemon configuration command telnet_port */
 618 COMMAND_HANDLER(handle_telnet_port_command)
 619 {
 620         return CALL_COMMAND_HANDLER(server_pipe_command, &telnet_port);
 621 }
 622
 623 COMMAND_HANDLER(handle_exit_command)
 624 {
 625         return ERROR_COMMAND_CLOSE_CONNECTION;
 626 }
 627
 628 static const struct command_registration telnet_command_handlers[] = {
 629         {
 630                 .name = "exit",
 631                 .handler = handle_exit_command,
 632                 .mode = COMMAND_EXEC,
 633                 .usage = "",
 634                 .help = "exit telnet session",
 635         },
 636         {
 637                 .name = "telnet_port",
 638                 .handler = handle_telnet_port_command,
 639                 .mode = COMMAND_ANY,
 640                 .help = "Specify port on which to listen "
 641                         "for incoming telnet connections.  "
 642                         "Read help on 'gdb_port'.",
 643                 .usage = "[port_num]",
 644         },
 645         COMMAND_REGISTRATION_DONE
 646 };
 647
 648 int telnet_register_commands(struct command_context *cmd_ctx)
 649 {
 650         telnet_port = strdup("4444");
 651         return register_commands(cmd_ctx, NULL, telnet_command_handlers);
 652 }