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   1 /***************************************************************************
   2  *   Copyright (C) 2005 by Dominic Rath                                    *
   3  *   Dominic.Rath@gmx.de                                                   *
   4  *                                                                         *
   5  *   This program is free software; you can redistribute it and/or modify  *
   6  *   it under the terms of the GNU General Public License as published by  *
   7  *   the Free Software Foundation; either version 2 of the License, or     *
   8  *   (at your option) any later version.                                   *
   9  *                                                                         *
  10  *   This program is distributed in the hope that it will be useful,       *
  11  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
  12  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
  13  *   GNU General Public License for more details.                          *
  14  *                                                                         *
  15  *   You should have received a copy of the GNU General Public License     *
  16  *   along with this program; if not, write to the                         *
  17  *   Free Software Foundation, Inc.,                                       *
  18  *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
  19  ***************************************************************************/
  20 #ifdef HAVE_CONFIG_H
  21 #include "config.h"
  22 #endif
  23
  24 #include "replacements.h"
  25
  26 #include "telnet_server.h"
  27
  28 #include "server.h"
  29 #include "log.h"
  30 #include "command.h"
  31 #include "target.h"
  32 #include "target_request.h"
  33
  34 #include <stdlib.h>
  35 #include <unistd.h>
  36 #include <errno.h>
  37 #include <string.h>
  38 #include <ctype.h>
  39
  40 static unsigned short telnet_port = 0;
  41
  42 int handle_exit_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc);
  43 int handle_telnet_port_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc);
  44
  45 static char *negotiate =
  46                 "\xFF\xFB\x03"          /* IAC WILL Suppress Go Ahead */
  47                 "\xFF\xFB\x01"          /* IAC WILL Echo */
  48                 "\xFF\xFD\x03"          /* IAC DO Suppress Go Ahead */
  49                 "\xFF\xFE\x01";         /* IAC DON'T Echo */
  50
  51 #define CTRL(c) (c - '@')
  52
  53 void telnet_prompt(connection_t *connection)
  54 {
  55         telnet_connection_t *t_con = connection->priv;
  56
  57         write_socket(connection->fd, t_con->prompt, strlen(t_con->prompt));
  58 }
  59
  60 int telnet_output(struct command_context_s *cmd_ctx, char* line)
  61 {
  62         connection_t *connection = cmd_ctx->output_handler_priv;
  63
  64         write_socket(connection->fd, line, strlen(line));
  65         write_socket(connection->fd, "\r\n\0", 3);
  66
  67         return ERROR_OK;
  68 }
  69
  70 int telnet_target_callback_event_handler(struct target_s *target, enum target_event event, void *priv)
  71 {
  72         struct command_context_s *cmd_ctx = priv;
  73         connection_t *connection = cmd_ctx->output_handler_priv;
  74         telnet_connection_t *t_con = connection->priv;
  75         char buffer[512];
  76
  77         switch (event)
  78         {
  79                 case TARGET_EVENT_HALTED:
  80                         command_print(cmd_ctx, "Target %i halted", get_num_by_target(target));
  81                         target->type->arch_state(target, buffer, 512);
  82                         buffer[511] = 0;
  83                         command_print(cmd_ctx, "%s", buffer);
  84                         telnet_prompt(connection);
  85                         t_con->suppress_prompt = 1;
  86                         break;
  87                 case TARGET_EVENT_RESUMED:
  88                         command_print(cmd_ctx, "Target %i resumed", get_num_by_target(target));
  89                         telnet_prompt(connection);
  90                         t_con->suppress_prompt = 1;
  91                         break;
  92                 default:
  93                         break;
  94         }
  95
  96         return ERROR_OK;
  97 }
  98
  99 int telnet_new_connection(connection_t *connection)
 100 {
 101         telnet_connection_t *telnet_connection = malloc(sizeof(telnet_connection_t));
 102         telnet_service_t *telnet_service = connection->service->priv;
 103         int i;
 104
 105         connection->priv = telnet_connection;
 106
 107         /* initialize telnet connection information */
 108         telnet_connection->line_size = 0;
 109         telnet_connection->line_cursor = 0;
 110         telnet_connection->option_size = 0;
 111         telnet_connection->prompt = strdup("> ");
 112         telnet_connection->suppress_prompt = 0;
 113         telnet_connection->state = TELNET_STATE_DATA;
 114
 115         /* output goes through telnet connection */
 116         command_set_output_handler(connection->cmd_ctx, telnet_output, connection);
 117
 118         /* negotiate telnet options */
 119         write_socket(connection->fd, negotiate, strlen(negotiate));
 120
 121         /* print connection banner */
 122         if (telnet_service->banner)
 123         {
 124                 write_socket(connection->fd, telnet_service->banner, strlen(telnet_service->banner));
 125                 write_socket(connection->fd, "\r\n\0", 3);
 126         }
 127
 128         telnet_prompt(connection);
 129
 130         /* initialize history */
 131         for (i = 0; i < TELNET_LINE_HISTORY_SIZE; i++)
 132         {
 133                 telnet_connection->history[i] = NULL;
 134         }
 135         telnet_connection->next_history = 0;
 136         telnet_connection->current_history = 0;
 137
 138         target_register_event_callback(telnet_target_callback_event_handler, connection->cmd_ctx);
 139
 140         return ERROR_OK;
 141 }
 142
 143 void telnet_clear_line(connection_t *connection, telnet_connection_t *t_con)
 144 {
 145         /* move to end of line */
 146         if (t_con->line_cursor < t_con->line_size)
 147         {
 148                 write_socket(connection->fd, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor);
 149         }
 150
 151         /* backspace, overwrite with space, backspace */
 152         while (t_con->line_size > 0)
 153         {
 154                 write_socket(connection->fd, "\b \b", 3);
 155                 t_con->line_size--;
 156         }
 157         t_con->line_cursor = 0;
 158 }
 159
 160 int telnet_input(connection_t *connection)
 161 {
 162         int bytes_read;
 163         char buffer[TELNET_BUFFER_SIZE];
 164         char *buf_p;
 165         telnet_connection_t *t_con = connection->priv;
 166         command_context_t *command_context = connection->cmd_ctx;
 167
 168         bytes_read = read_socket(connection->fd, buffer, TELNET_BUFFER_SIZE);
 169
 170         if (bytes_read == 0)
 171                 return ERROR_SERVER_REMOTE_CLOSED;
 172         else if (bytes_read == -1)
 173         {
 174                 ERROR("error during read: %s", strerror(errno));
 175                 return ERROR_SERVER_REMOTE_CLOSED;
 176         }
 177
 178         buf_p = buffer;
 179         while (bytes_read)
 180         {
 181                 switch (t_con->state)
 182                 {
 183                         case TELNET_STATE_DATA:
 184                                 if (*buf_p == '\xff')
 185                                 {
 186                                         t_con->state = TELNET_STATE_IAC;
 187                                 }
 188                                 else
 189                                 {
 190                                         if (isprint(*buf_p)) /* printable character */
 191                                         {
 192                                                 write_socket(connection->fd, buf_p, 1);
 193                                                 if (t_con->line_cursor == t_con->line_size)
 194                                                 {
 195                                                         t_con->line[t_con->line_size++] = *buf_p;
 196                                                         t_con->line_cursor++;
 197                                                 }
 198                                                 else
 199                                                 {
 200                                                         int i;
 201                                                         memmove(t_con->line + t_con->line_cursor + 1, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor);
 202                                                         t_con->line[t_con->line_cursor++] = *buf_p;
 203                                                         t_con->line_size++;
 204                                                         write_socket(connection->fd, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor);
 205                                                         for (i = t_con->line_cursor; i < t_con->line_size; i++)
 206                                                         {
 207                                                                 write_socket(connection->fd, "\b", 1);
 208                                                         }
 209                                                 }
 210                                         }
 211                                         else /* non-printable */
 212                                         {
 213                                                 if (*buf_p == 0x1b) /* escape */
 214                                                 {
 215                                                         t_con->state = TELNET_STATE_ESCAPE;
 216                                                         t_con->last_escape = '\x00';
 217                                                 }
 218                                                 else if ((*buf_p == 0xd) || (*buf_p == 0xa)) /* CR/LF */
 219                                                 {
 220                                                         int retval;
 221
 222                                                         /* skip over combinations with CR/LF + NUL */
 223                                                         if (((*(buf_p + 1) == 0xa) || (*(buf_p + 1) == 0xd)) && (bytes_read > 1))
 224                                                         {
 225                                                                 buf_p++;
 226                                                                 bytes_read--;
 227                                                         }
 228                                                         if ((*(buf_p + 1) == 0) && (bytes_read > 1))
 229                                                         {
 230                                                                 buf_p++;
 231                                                                 bytes_read--;
 232                                                         }
 233                                                         t_con->line[t_con->line_size] = 0;
 234
 235                                                         write_socket(connection->fd, "\r\n\x00", 3);
 236
 237                                                         if (strcmp(t_con->line, "history") == 0)
 238                                                         {
 239                                                                 int i;
 240                                                                 for (i = 0; i < TELNET_LINE_HISTORY_SIZE; i++)
 241                                                                 {
 242                                                                         if (t_con->history[i])
 243                                                                         {
 244                                                                                 write_socket(connection->fd, t_con->history[i], strlen(t_con->history[i]));
 245                                                                                 write_socket(connection->fd, "\r\n\x00", 3);
 246                                                                         }
 247                                                                 }
 248                                                                 telnet_prompt(connection);
 249                                                                 t_con->line_size = 0;
 250                                                                 t_con->line_cursor = 0;
 251                                                                 continue;
 252                                                         }
 253
 254                                                         /* we're running a command, so we need a prompt
 255                                                          * if the output handler is called, this gets set again */
 256                                                         t_con->suppress_prompt = 0;
 257                                                         if ((retval = command_run_line(command_context, t_con->line)) != ERROR_OK)
 258                                                         {
 259                                                                 if (retval == ERROR_COMMAND_CLOSE_CONNECTION)
 260                                                                 {
 261                                                                         return ERROR_SERVER_REMOTE_CLOSED;
 262                                                                 }
 263                                                         }
 264
 265                                                         /* Save only non-blank lines in the history */
 266                                                         if (t_con->line_size > 0)
 267                                                         {
 268                                                                 /* if the history slot is already taken, free it */
 269                                                                 if (t_con->history[t_con->next_history])
 270                                                                 {
 271                                                                         free(t_con->history[t_con->next_history]);
 272                                                                 }
 273
 274                                                                 /* add line to history */
 275                                                                 t_con->history[t_con->next_history] = strdup(t_con->line);
 276
 277                                                                 /* wrap history at TELNET_LINE_HISTORY_SIZE */
 278                                                                 t_con->next_history = (t_con->next_history + 1) % TELNET_LINE_HISTORY_SIZE;
 279
 280                                                                 /* current history line starts at the new entry */
 281                                                                 t_con->current_history = t_con->next_history;
 282
 283                                                                 if (t_con->history[t_con->current_history])
 284                                                                 {
 285                                                                         free(t_con->history[t_con->current_history]);
 286                                                                 }
 287                                                                 t_con->history[t_con->current_history] = strdup("");
 288                                                         }
 289
 290                                                         if (!t_con->suppress_prompt)
 291                                                         {
 292                                                                 telnet_prompt(connection);
 293                                                         }
 294                                                         else
 295                                                         {
 296                                                                 t_con->suppress_prompt = 0;
 297                                                         }
 298
 299                                                         t_con->line_size = 0;
 300                                                         t_con->line_cursor = 0;
 301                                                 }
 302                                                 else if ((*buf_p == 0x7f) || (*buf_p == 0x8)) /* delete character */
 303                                                 {
 304                                                         if (t_con->line_cursor > 0)
 305                                                         {
 306                                                                 if (t_con->line_cursor != t_con->line_size)
 307                                                                 {
 308                                                                         int i;
 309                                                                         write_socket(connection->fd, "\b", 1);
 310                                                                         t_con->line_cursor--;
 311                                                                         t_con->line_size--;
 312                                                                         memmove(t_con->line + t_con->line_cursor, t_con->line + t_con->line_cursor + 1, t_con->line_size - t_con->line_cursor);
 313
 314                                                                         write_socket(connection->fd, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor);
 315                                                                         write_socket(connection->fd, " \b", 2);
 316                                                                         for (i = t_con->line_cursor; i < t_con->line_size; i++)
 317                                                                         {
 318                                                                                 write_socket(connection->fd, "\b", 1);
 319                                                                         }
 320                                                                 }
 321                                                                 else
 322                                                                 {
 323                                                                         t_con->line_size--;
 324                                                                         t_con->line_cursor--;
 325                                                                         /* back space: move the 'printer' head one char back, overwrite with space, move back again */
 326                                                                         write_socket(connection->fd, "\b \b", 3);
 327                                                                 }
 328                                                         }
 329                                                 }
 330                                                 else if (*buf_p == 0x15) /* clear line */
 331                                                 {
 332                                                         telnet_clear_line(connection, t_con);
 333                                                 }
 334                                                 else if (*buf_p == CTRL('B')) /* cursor left */
 335                                                 {
 336                                                         if (t_con->line_cursor > 0)
 337                                                         {
 338                                                                 write_socket(connection->fd, "\b", 1);
 339                                                                 t_con->line_cursor--;
 340                                                         }
 341                                                         t_con->state = TELNET_STATE_DATA;
 342                                                 }
 343                                                 else if (*buf_p == CTRL('F')) /* cursor right */
 344                                                 {
 345                                                         if (t_con->line_cursor < t_con->line_size)
 346                                                         {
 347                                                                 write_socket(connection->fd, t_con->line + t_con->line_cursor++, 1);
 348                                                         }
 349                                                         t_con->state = TELNET_STATE_DATA;
 350                                                 }
 351                                                 else
 352                                                 {
 353                                                         DEBUG("unhandled nonprintable: %2.2x", *buf_p);
 354                                                 }
 355                                         }
 356                                 }
 357                                 break;
 358                         case TELNET_STATE_IAC:
 359                                 switch (*buf_p)
 360                                 {
 361                                         case '\xfe':
 362                                                 t_con->state = TELNET_STATE_DONT;
 363                                                 break;
 364                                         case '\xfd':
 365                                                 t_con->state = TELNET_STATE_DO;
 366                                                 break;
 367                                         case '\xfc':
 368                                                 t_con->state = TELNET_STATE_WONT;
 369                                                 break;
 370                                         case '\xfb':
 371                                                 t_con->state = TELNET_STATE_WILL;
 372                                                 break;
 373                                 }
 374                                 break;
 375                         case TELNET_STATE_SB:
 376                                 break;
 377                         case TELNET_STATE_SE:
 378                                 break;
 379                         case TELNET_STATE_WILL:
 380                         case TELNET_STATE_WONT:
 381                         case TELNET_STATE_DO:
 382                         case TELNET_STATE_DONT:
 383                                 t_con->state = TELNET_STATE_DATA;
 384                                 break;
 385                         case TELNET_STATE_ESCAPE:
 386                                 if (t_con->last_escape == '[')
 387                                 {
 388                                         if (*buf_p == 'D') /* cursor left */
 389                                         {
 390                                                 if (t_con->line_cursor > 0)
 391                                                 {
 392                                                         write_socket(connection->fd, "\b", 1);
 393                                                         t_con->line_cursor--;
 394                                                 }
 395                                                 t_con->state = TELNET_STATE_DATA;
 396                                         }
 397                                         else if (*buf_p == 'C') /* cursor right */
 398                                         {
 399                                                 if (t_con->line_cursor < t_con->line_size)
 400                                                 {
 401                                                         write_socket(connection->fd, t_con->line + t_con->line_cursor++, 1);
 402                                                 }
 403                                                 t_con->state = TELNET_STATE_DATA;
 404                                         }
 405                                         else if (*buf_p == 'A') /* cursor up */
 406                                         {
 407                                                 int last_history = (t_con->current_history > 0) ? t_con->current_history - 1 : TELNET_LINE_HISTORY_SIZE-1;
 408                                                 if (t_con->history[last_history])
 409                                                 {
 410                                                         telnet_clear_line(connection, t_con);
 411                                                         t_con->line_size = strlen(t_con->history[last_history]);
 412                                                         t_con->line_cursor = t_con->line_size;
 413                                                         memcpy(t_con->line, t_con->history[last_history], t_con->line_size + 1);
 414                                                         write_socket(connection->fd, t_con->line, t_con->line_size);
 415                                                         t_con->current_history = last_history;
 416                                                 }
 417                                                 t_con->state = TELNET_STATE_DATA;
 418                                         }
 419                                         else if (*buf_p == 'B') /* cursor down */
 420                                         {
 421                                                 int next_history = (t_con->current_history + 1) % TELNET_LINE_HISTORY_SIZE;
 422                                                 if (t_con->history[next_history])
 423                                                 {
 424                                                         telnet_clear_line(connection, t_con);
 425                                                         t_con->line_size = strlen(t_con->history[next_history]);
 426                                                         t_con->line_cursor = t_con->line_size;
 427                                                         memcpy(t_con->line, t_con->history[next_history], t_con->line_size + 1);
 428                                                         write_socket(connection->fd, t_con->line, t_con->line_size);
 429                                                         t_con->current_history = next_history;
 430                                                 }
 431                                                 t_con->state = TELNET_STATE_DATA;
 432                                         }
 433                                         else if (*buf_p == '3')
 434                                         {
 435                                                 t_con->last_escape = *buf_p;
 436                                         }
 437                                         else
 438                                         {
 439                                                 t_con->state = TELNET_STATE_DATA;
 440                                         }
 441                                 }
 442                                 else if (t_con->last_escape == '3')
 443                                 {
 444                                         /* Remove character */
 445                                         if (*buf_p == '~')
 446                                         {
 447                                                 if (t_con->line_cursor < t_con->line_size)
 448                                                 {
 449                                                         int i;
 450                                                         t_con->line_size--;
 451                                                         /* remove char from line buffer */
 452                                                         memmove(t_con->line + t_con->line_cursor, t_con->line + t_con->line_cursor + 1, t_con->line_size - t_con->line_cursor);
 453
 454                                                         /* print remainder of buffer */
 455                                                         write_socket(connection->fd, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor);
 456                                                         /* overwrite last char with whitespace */
 457                                                         write_socket(connection->fd, " \b", 2);
 458
 459                                                         /* move back to cursor position*/
 460                                                         for (i = t_con->line_cursor; i < t_con->line_size; i++)
 461                                                         {
 462                                                                 write_socket(connection->fd, "\b", 1);
 463                                                         }
 464                                                 }
 465
 466                                                 t_con->state = TELNET_STATE_DATA;
 467                                         }
 468                                         else
 469                                         {
 470                                                 t_con->state = TELNET_STATE_DATA;
 471                                         }
 472                                 }
 473                                 else if (t_con->last_escape == '\x00')
 474                                 {
 475                                         if (*buf_p == '[')
 476                                         {
 477                                                 t_con->last_escape = *buf_p;
 478                                         }
 479                                         else
 480                                         {
 481                                                 t_con->state = TELNET_STATE_DATA;
 482                                         }
 483                                 }
 484                                 else
 485                                 {
 486                                         ERROR("BUG: unexpected value in t_con->last_escape");
 487                                         t_con->state = TELNET_STATE_DATA;
 488                                 }
 489
 490                                 break;
 491                         default:
 492                                 ERROR("unknown telnet state");
 493                                 exit(-1);
 494                 }
 495
 496                 bytes_read--;
 497                 buf_p++;
 498         }
 499
 500         return ERROR_OK;
 501 }
 502
 503 int telnet_connection_closed(connection_t *connection)
 504 {
 505         telnet_connection_t *t_con = connection->priv;
 506         int i;
 507
 508         if (t_con->prompt)
 509                 free(t_con->prompt);
 510
 511         for (i = 0; i < TELNET_LINE_HISTORY_SIZE; i++)
 512         {
 513                 if (t_con->history[i])
 514                         free(t_con->history[i]);
 515         }
 516
 517         /* if this connection registered a debug-message receiver delete it */
 518         delete_debug_msg_receiver(connection->cmd_ctx, NULL);
 519
 520         if (connection->priv)
 521                 free(connection->priv);
 522         else
 523                 ERROR("BUG: connection->priv == NULL");
 524
 525         target_unregister_event_callback(telnet_target_callback_event_handler, connection->cmd_ctx);
 526
 527         return ERROR_OK;
 528 }
 529
 530 int telnet_set_prompt(connection_t *connection, char *prompt)
 531 {
 532         telnet_connection_t *t_con = connection->priv;
 533
 534         t_con->prompt = strdup(prompt);
 535
 536         return ERROR_OK;
 537 }
 538
 539 int telnet_init(char *banner)
 540 {
 541         telnet_service_t *telnet_service = malloc(sizeof(telnet_service_t));
 542
 543         if (telnet_port == 0)
 544         {
 545                 WARNING("no telnet port specified, using default port 4444");
 546                 telnet_port = 4444;
 547         }
 548
 549         telnet_service->banner = banner;
 550
 551         add_service("telnet", CONNECTION_TELNET, telnet_port, 1, telnet_new_connection, telnet_input, telnet_connection_closed, telnet_service);
 552
 553         return ERROR_OK;
 554 }
 555
 556 int telnet_register_commands(command_context_t *command_context)
 557 {
 558         register_command(command_context, NULL, "exit", handle_exit_command,
 559                                          COMMAND_EXEC, "exit telnet session");
 560
 561         register_command(command_context, NULL, "telnet_port", handle_telnet_port_command,
 562                                          COMMAND_CONFIG, "");
 563
 564         return ERROR_OK;
 565 }
 566
 567 /* daemon configuration command telnet_port */
 568 int handle_telnet_port_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc)
 569 {
 570         if (argc == 0)
 571                 return ERROR_OK;
 572
 573         /* only if the port wasn't overwritten by cmdline */
 574         if (telnet_port == 0)
 575                 telnet_port = strtoul(args[0], NULL, 0);
 576
 577         return ERROR_OK;
 578 }
 579
 580 int handle_exit_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc)
 581 {
 582         return ERROR_COMMAND_CLOSE_CONNECTION;
 583 }