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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->prompt = strdup("> ");
 226         telnet_connection->state = TELNET_STATE_DATA;
 227
 228         /* output goes through telnet connection */
 229         command_set_output_handler(connection->cmd_ctx, telnet_output, connection);
 230
 231         /* negotiate telnet options */
 232         telnet_write(connection, negotiate, strlen(negotiate));
 233
 234         /* print connection banner */
 235         if (telnet_service->banner) {
 236                 telnet_write(connection, telnet_service->banner, strlen(telnet_service->banner));
 237                 telnet_write(connection, "\r\n", 2);
 238         }
 239
 240         /* the prompt is always placed at the line beginning */
 241         telnet_write(connection, "\r", 1);
 242         telnet_prompt(connection);
 243
 244         /* initialize history */
 245         for (i = 0; i < TELNET_LINE_HISTORY_SIZE; i++)
 246                 telnet_connection->history[i] = NULL;
 247         telnet_connection->next_history = 0;
 248         telnet_connection->current_history = 0;
 249         telnet_load_history(telnet_connection);
 250
 251         log_add_callback(telnet_log_callback, connection);
 252
 253         return ERROR_OK;
 254 }
 255
 256 static void telnet_clear_line(struct connection *connection,
 257         struct telnet_connection *t_con)
 258 {
 259         /* move to end of line */
 260         if (t_con->line_cursor < t_con->line_size)
 261                 telnet_write(connection,
 262                         t_con->line + t_con->line_cursor,
 263                         t_con->line_size - t_con->line_cursor);
 264
 265         /* backspace, overwrite with space, backspace */
 266         while (t_con->line_size > 0) {
 267                 telnet_write(connection, "\b \b", 3);
 268                 t_con->line_size--;
 269         }
 270         t_con->line_cursor = 0;
 271 }
 272
 273 static void telnet_history_go(struct connection *connection, int idx)
 274 {
 275         struct telnet_connection *t_con = connection->priv;
 276
 277         if (t_con->history[idx]) {
 278                 telnet_clear_line(connection, t_con);
 279                 t_con->line_size = strlen(t_con->history[idx]);
 280                 t_con->line_cursor = t_con->line_size;
 281                 memcpy(t_con->line, t_con->history[idx], t_con->line_size);
 282                 telnet_write(connection, t_con->line, t_con->line_size);
 283                 t_con->current_history = idx;
 284         }
 285         t_con->state = TELNET_STATE_DATA;
 286 }
 287
 288 static void telnet_history_up(struct connection *connection)
 289 {
 290         struct telnet_connection *t_con = connection->priv;
 291
 292         int last_history = (t_con->current_history > 0) ?
 293                                 t_con->current_history - 1 :
 294                                 TELNET_LINE_HISTORY_SIZE-1;
 295         telnet_history_go(connection, last_history);
 296 }
 297
 298 static void telnet_history_down(struct connection *connection)
 299 {
 300         struct telnet_connection *t_con = connection->priv;
 301
 302         int next_history = (t_con->current_history + 1) % TELNET_LINE_HISTORY_SIZE;
 303         telnet_history_go(connection, next_history);
 304 }
 305
 306 static void telnet_move_cursor(struct connection *connection, size_t pos)
 307 {
 308         struct telnet_connection *tc;
 309         size_t tmp;
 310
 311         tc = connection->priv;
 312
 313         if (pos < tc->line_cursor) {
 314                 tmp = tc->line_cursor - pos;
 315
 316                 for (size_t i = 0; i < tmp; i += 16)
 317                         telnet_write(connection, "\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b",
 318                                 MIN(tmp - i, 16));
 319         } else {
 320                 tmp = pos - tc->line_cursor;
 321
 322                 for (size_t i = 0; i < tmp; i += 16)
 323                         telnet_write(connection, tc->line + tc->line_cursor + i,
 324                                 MIN(tmp - i, 16));
 325         }
 326
 327         tc->line_cursor = pos;
 328 }
 329
 330 static int telnet_input(struct connection *connection)
 331 {
 332         int bytes_read;
 333         unsigned char buffer[TELNET_BUFFER_SIZE];
 334         unsigned char *buf_p;
 335         struct telnet_connection *t_con = connection->priv;
 336         struct command_context *command_context = connection->cmd_ctx;
 337
 338         bytes_read = connection_read(connection, buffer, TELNET_BUFFER_SIZE);
 339
 340         if (bytes_read == 0)
 341                 return ERROR_SERVER_REMOTE_CLOSED;
 342         else if (bytes_read == -1) {
 343                 LOG_ERROR("error during read: %s", strerror(errno));
 344                 return ERROR_SERVER_REMOTE_CLOSED;
 345         }
 346
 347         buf_p = buffer;
 348         while (bytes_read) {
 349                 switch (t_con->state) {
 350                         case TELNET_STATE_DATA:
 351                                 if (*buf_p == 0xff)
 352                                         t_con->state = TELNET_STATE_IAC;
 353                                 else {
 354                                         if (isprint(*buf_p)) {  /* printable character */
 355                                                 /* watch buffer size leaving one spare character for
 356                                                  * string null termination */
 357                                                 if (t_con->line_size == TELNET_LINE_MAX_SIZE-1) {
 358                                                         /* output audible bell if buffer is full
 359                                                          * "\a" does not work, at least on windows */
 360                                                         telnet_write(connection, "\x07", 1);
 361                                                 } else if (t_con->line_cursor == t_con->line_size) {
 362                                                         telnet_write(connection, buf_p, 1);
 363                                                         t_con->line[t_con->line_size++] = *buf_p;
 364                                                         t_con->line_cursor++;
 365                                                 } else {
 366                                                         int i;
 367                                                         memmove(t_con->line + t_con->line_cursor + 1,
 368                                                                         t_con->line + t_con->line_cursor,
 369                                                                         t_con->line_size - t_con->line_cursor);
 370                                                         t_con->line[t_con->line_cursor] = *buf_p;
 371                                                         t_con->line_size++;
 372                                                         telnet_write(connection,
 373                                                                         t_con->line + t_con->line_cursor,
 374                                                                         t_con->line_size - t_con->line_cursor);
 375                                                         t_con->line_cursor++;
 376                                                         for (i = t_con->line_cursor; i < t_con->line_size; i++)
 377                                                                 telnet_write(connection, "\b", 1);
 378                                                 }
 379                                         } else {        /* non-printable */
 380                                                 if (*buf_p == 0x1b) {   /* escape */
 381                                                         t_con->state = TELNET_STATE_ESCAPE;
 382                                                         t_con->last_escape = '\x00';
 383                                                 } else if ((*buf_p == 0xd) || (*buf_p == 0xa)) {        /* CR/LF */
 384                                                         int retval;
 385
 386                                                         /* skip over combinations with CR/LF and NUL characters */
 387                                                         if ((bytes_read > 1) && ((*(buf_p + 1) == 0xa) ||
 388                                                                         (*(buf_p + 1) == 0xd))) {
 389                                                                 buf_p++;
 390                                                                 bytes_read--;
 391                                                         }
 392                                                         if ((bytes_read > 1) && (*(buf_p + 1) == 0)) {
 393                                                                 buf_p++;
 394                                                                 bytes_read--;
 395                                                         }
 396                                                         t_con->line[t_con->line_size] = 0;
 397
 398                                                         telnet_write(connection, "\r\n\x00", 3);
 399
 400                                                         if (strcmp(t_con->line, "history") == 0) {
 401                                                                 int i;
 402                                                                 for (i = 1; i < TELNET_LINE_HISTORY_SIZE; i++) {
 403                                                                         /* the t_con->next_history line contains empty string
 404                                                                          * (unless NULL), thus it is not printed */
 405                                                                         char *history_line = t_con->history[(t_con->
 406                                                                                         next_history + i) %
 407                                                                                         TELNET_LINE_HISTORY_SIZE];
 408                                                                         if (history_line) {
 409                                                                                 telnet_write(connection, history_line,
 410                                                                                                 strlen(history_line));
 411                                                                                 telnet_write(connection, "\r\n\x00", 3);
 412                                                                         }
 413                                                                 }
 414                                                                 t_con->line_size = 0;
 415                                                                 t_con->line_cursor = 0;
 416                                                                 continue;
 417                                                         }
 418
 419                                                         /* save only non-blank not repeating lines in the history */
 420                                                         char *prev_line = t_con->history[(t_con->current_history > 0) ?
 421                                                                         t_con->current_history - 1 : TELNET_LINE_HISTORY_SIZE-1];
 422                                                         if (*t_con->line && (prev_line == NULL ||
 423                                                                         strcmp(t_con->line, prev_line))) {
 424                                                                 /* if the history slot is already taken, free it */
 425                                                                 if (t_con->history[t_con->next_history])
 426                                                                         free(t_con->history[t_con->next_history]);
 427
 428                                                                 /* add line to history */
 429                                                                 t_con->history[t_con->next_history] = strdup(t_con->line);
 430
 431                                                                 /* wrap history at TELNET_LINE_HISTORY_SIZE */
 432                                                                 t_con->next_history = (t_con->next_history + 1) %
 433                                                                                 TELNET_LINE_HISTORY_SIZE;
 434
 435                                                                 /* current history line starts at the new entry */
 436                                                                 t_con->current_history =
 437                                                                                 t_con->next_history;
 438
 439                                                                 if (t_con->history[t_con->current_history])
 440                                                                         free(t_con->history[t_con->current_history]);
 441                                                                 t_con->history[t_con->current_history] = strdup("");
 442                                                         }
 443
 444                                                         t_con->line_size = 0;
 445
 446                                                         /* to suppress prompt in log callback during command execution */
 447                                                         t_con->line_cursor = -1;
 448
 449                                                         if (strcmp(t_con->line, "shutdown") == 0)
 450                                                                 telnet_save_history(t_con);
 451
 452                                                         retval = command_run_line(command_context, t_con->line);
 453
 454                                                         t_con->line_cursor = 0;
 455
 456                                                         if (retval == ERROR_COMMAND_CLOSE_CONNECTION)
 457                                                                 return ERROR_SERVER_REMOTE_CLOSED;
 458
 459                                                         /* the prompt is always * placed at the line beginning */
 460                                                         telnet_write(connection, "\r", 1);
 461
 462                                                         retval = telnet_prompt(connection);
 463                                                         if (retval == ERROR_SERVER_REMOTE_CLOSED)
 464                                                                 return ERROR_SERVER_REMOTE_CLOSED;
 465
 466                                                 } else if ((*buf_p == 0x7f) || (*buf_p == 0x8)) {       /* delete character */
 467                                                         if (t_con->line_cursor > 0) {
 468                                                                 if (t_con->line_cursor != t_con->line_size) {
 469                                                                         int i;
 470                                                                         telnet_write(connection, "\b", 1);
 471                                                                         t_con->line_cursor--;
 472                                                                         t_con->line_size--;
 473                                                                         memmove(t_con->line + t_con->line_cursor,
 474                                                                                         t_con->line + t_con->line_cursor + 1,
 475                                                                                         t_con->line_size -
 476                                                                                         t_con->line_cursor);
 477
 478                                                                         telnet_write(connection,
 479                                                                                         t_con->line + t_con->line_cursor,
 480                                                                                         t_con->line_size -
 481                                                                                         t_con->line_cursor);
 482                                                                         telnet_write(connection, " \b", 2);
 483                                                                         for (i = t_con->line_cursor; i < t_con->line_size; i++)
 484                                                                                 telnet_write(connection, "\b", 1);
 485                                                                 } else {
 486                                                                         t_con->line_size--;
 487                                                                         t_con->line_cursor--;
 488                                                                         /* back space: move the 'printer' head one char
 489                                                                          * back, overwrite with space, move back again */
 490                                                                         telnet_write(connection, "\b \b", 3);
 491                                                                 }
 492                                                         }
 493                                                 } else if (*buf_p == 0x15) /* clear line */
 494                                                         telnet_clear_line(connection, t_con);
 495                                                 else if (*buf_p == CTRL('B')) { /* cursor left */
 496                                                         if (t_con->line_cursor > 0) {
 497                                                                 telnet_write(connection, "\b", 1);
 498                                                                 t_con->line_cursor--;
 499                                                         }
 500                                                         t_con->state = TELNET_STATE_DATA;
 501                                                 } else if (*buf_p == CTRL('F')) {       /* cursor right */
 502                                                         if (t_con->line_cursor < t_con->line_size)
 503                                                                 telnet_write(connection, t_con->line + t_con->line_cursor++, 1);
 504                                                         t_con->state = TELNET_STATE_DATA;
 505                                                 } else if (*buf_p == CTRL('P'))         /* cursor up */
 506                                                         telnet_history_up(connection);
 507                                                 else if (*buf_p == CTRL('N'))           /* cursor down */
 508                                                         telnet_history_down(connection);
 509                                                 else if (*buf_p == CTRL('A'))
 510                                                         telnet_move_cursor(connection, 0);
 511                                                 else if (*buf_p == CTRL('E'))
 512                                                         telnet_move_cursor(connection, t_con->line_size);
 513                                                 else
 514                                                         LOG_DEBUG("unhandled nonprintable: %2.2x", *buf_p);
 515                                         }
 516                                 }
 517                                 break;
 518                         case TELNET_STATE_IAC:
 519                                 switch (*buf_p) {
 520                                 case 0xfe:
 521                                         t_con->state = TELNET_STATE_DONT;
 522                                         break;
 523                                 case 0xfd:
 524                                         t_con->state = TELNET_STATE_DO;
 525                                         break;
 526                                 case 0xfc:
 527                                         t_con->state = TELNET_STATE_WONT;
 528                                         break;
 529                                 case 0xfb:
 530                                         t_con->state = TELNET_STATE_WILL;
 531                                         break;
 532                                 }
 533                                 break;
 534                         case TELNET_STATE_SB:
 535                                 break;
 536                         case TELNET_STATE_SE:
 537                                 break;
 538                         case TELNET_STATE_WILL:
 539                         case TELNET_STATE_WONT:
 540                         case TELNET_STATE_DO:
 541                         case TELNET_STATE_DONT:
 542                                 t_con->state = TELNET_STATE_DATA;
 543                                 break;
 544                         case TELNET_STATE_ESCAPE:
 545                                 if (t_con->last_escape == '[') {
 546                                         if (*buf_p == 'D') {    /* cursor left */
 547                                                 if (t_con->line_cursor > 0) {
 548                                                         telnet_write(connection, "\b", 1);
 549                                                         t_con->line_cursor--;
 550                                                 }
 551                                                 t_con->state = TELNET_STATE_DATA;
 552                                         } else if (*buf_p == 'C') {     /* cursor right */
 553                                                 if (t_con->line_cursor < t_con->line_size)
 554                                                         telnet_write(connection,
 555                                                                         t_con->line + t_con->line_cursor++, 1);
 556                                                 t_con->state = TELNET_STATE_DATA;
 557                                         } else if (*buf_p == 'A') {     /* cursor up */
 558                                                 telnet_history_up(connection);
 559                                         } else if (*buf_p == 'B') {     /* cursor down */
 560                                                 telnet_history_down(connection);
 561                                         } else if (*buf_p == '3')
 562                                                 t_con->last_escape = *buf_p;
 563                                         else
 564                                                 t_con->state = TELNET_STATE_DATA;
 565                                 } else if (t_con->last_escape == '3') {
 566                                         /* Remove character */
 567                                         if (*buf_p == '~') {
 568                                                 if (t_con->line_cursor < t_con->line_size) {
 569                                                         int i;
 570                                                         t_con->line_size--;
 571                                                         /* remove char from line buffer */
 572                                                         memmove(t_con->line + t_con->line_cursor,
 573                                                                         t_con->line + t_con->line_cursor + 1,
 574                                                                         t_con->line_size - t_con->line_cursor);
 575
 576                                                         /* print remainder of buffer */
 577                                                         telnet_write(connection, t_con->line + t_con->line_cursor,
 578                                                                         t_con->line_size - t_con->line_cursor);
 579                                                         /* overwrite last char with whitespace */
 580                                                         telnet_write(connection, " \b", 2);
 581
 582                                                         /* move back to cursor position*/
 583                                                         for (i = t_con->line_cursor; i < t_con->line_size; i++)
 584                                                                 telnet_write(connection, "\b", 1);
 585                                                 }
 586
 587                                                 t_con->state = TELNET_STATE_DATA;
 588                                         } else
 589                                                 t_con->state = TELNET_STATE_DATA;
 590                                 } else if (t_con->last_escape == '\x00') {
 591                                         if (*buf_p == '[')
 592                                                 t_con->last_escape = *buf_p;
 593                                         else
 594                                                 t_con->state = TELNET_STATE_DATA;
 595                                 } else {
 596                                         LOG_ERROR("BUG: unexpected value in t_con->last_escape");
 597                                         t_con->state = TELNET_STATE_DATA;
 598                                 }
 599
 600                                 break;
 601                         default:
 602                                 LOG_ERROR("unknown telnet state");
 603                                 return ERROR_FAIL;
 604                 }
 605
 606                 bytes_read--;
 607                 buf_p++;
 608         }
 609
 610         return ERROR_OK;
 611 }
 612
 613 static int telnet_connection_closed(struct connection *connection)
 614 {
 615         struct telnet_connection *t_con = connection->priv;
 616         int i;
 617
 618         log_remove_callback(telnet_log_callback, connection);
 619
 620         if (t_con->prompt) {
 621                 free(t_con->prompt);
 622                 t_con->prompt = NULL;
 623         }
 624
 625         /* save telnet history */
 626         telnet_save_history(t_con);
 627
 628         for (i = 0; i < TELNET_LINE_HISTORY_SIZE; i++) {
 629                 if (t_con->history[i]) {
 630                         free(t_con->history[i]);
 631                         t_con->history[i] = NULL;
 632                 }
 633         }
 634
 635         /* if this connection registered a debug-message receiver delete it */
 636         delete_debug_msg_receiver(connection->cmd_ctx, NULL);
 637
 638         if (connection->priv) {
 639                 free(connection->priv);
 640                 connection->priv = NULL;
 641         } else
 642                 LOG_ERROR("BUG: connection->priv == NULL");
 643
 644         return ERROR_OK;
 645 }
 646
 647 int telnet_init(char *banner)
 648 {
 649         if (strcmp(telnet_port, "disabled") == 0) {
 650                 LOG_INFO("telnet server disabled");
 651                 return ERROR_OK;
 652         }
 653
 654         struct telnet_service *telnet_service =
 655                 malloc(sizeof(struct telnet_service));
 656
 657         if (!telnet_service) {
 658                 LOG_ERROR("Failed to allocate telnet service.");
 659                 return ERROR_FAIL;
 660         }
 661
 662         telnet_service->banner = banner;
 663
 664         int ret = add_service("telnet", telnet_port, CONNECTION_LIMIT_UNLIMITED,
 665                 telnet_new_connection, telnet_input, telnet_connection_closed,
 666                 telnet_service);
 667
 668         if (ret != ERROR_OK) {
 669                 free(telnet_service);
 670                 return ret;
 671         }
 672
 673         return ERROR_OK;
 674 }
 675
 676 /* daemon configuration command telnet_port */
 677 COMMAND_HANDLER(handle_telnet_port_command)
 678 {
 679         return CALL_COMMAND_HANDLER(server_pipe_command, &telnet_port);
 680 }
 681
 682 COMMAND_HANDLER(handle_exit_command)
 683 {
 684         return ERROR_COMMAND_CLOSE_CONNECTION;
 685 }
 686
 687 static const struct command_registration telnet_command_handlers[] = {
 688         {
 689                 .name = "exit",
 690                 .handler = handle_exit_command,
 691                 .mode = COMMAND_EXEC,
 692                 .usage = "",
 693                 .help = "exit telnet session",
 694         },
 695         {
 696                 .name = "telnet_port",
 697                 .handler = handle_telnet_port_command,
 698                 .mode = COMMAND_ANY,
 699                 .help = "Specify port on which to listen "
 700                         "for incoming telnet connections.  "
 701                         "Read help on 'gdb_port'.",
 702                 .usage = "[port_num]",
 703         },
 704         COMMAND_REGISTRATION_DONE
 705 };
 706
 707 int telnet_register_commands(struct command_context *cmd_ctx)
 708 {
 709         telnet_port = strdup("4444");
 710         return register_commands(cmd_ctx, NULL, telnet_command_handlers);
 711 }