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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_outputline(connection_t *connection, char* line)
  61 {
  62         write_socket(connection->fd, line, strlen(line));
  63         return write_socket(connection->fd, "\r\n\0", 3);
  64 }
  65
  66 int telnet_output(struct command_context_s *cmd_ctx, char* line)
  67 {
  68         connection_t *connection = cmd_ctx->output_handler_priv;
  69
  70         write_socket(connection->fd, line, strlen(line));
  71         write_socket(connection->fd, "\r\n\0", 3);
  72
  73         return ERROR_OK;
  74 }
  75
  76 void telnet_log_callback(void *privData, const char *file, int line,
  77                 const char *function, const char *format, va_list args)
  78 {
  79         connection_t *connection = (connection_t *)privData;
  80         char *t = allocPrintf(format, args);
  81         if (t == NULL)
  82                 return;
  83
  84         telnet_outputline(connection, t);
  85
  86         free(t);
  87 }
  88
  89 int telnet_target_callback_event_handler(struct target_s *target, enum target_event event, void *priv)
  90 {
  91         struct command_context_s *cmd_ctx = priv;
  92         connection_t *connection = cmd_ctx->output_handler_priv;
  93         telnet_connection_t *t_con = connection->priv;
  94         char buffer[512];
  95
  96         switch (event)
  97         {
  98                 case TARGET_EVENT_HALTED:
  99                         command_print(cmd_ctx, "Target %i halted", get_num_by_target(target));
 100                         target->type->arch_state(target, buffer, 512);
 101                         buffer[511] = 0;
 102                         command_print(cmd_ctx, "%s", buffer);
 103                         if (!t_con->suppress_prompt)
 104                                 telnet_prompt(connection);
 105                         break;
 106                 case TARGET_EVENT_RESUMED:
 107                         command_print(cmd_ctx, "Target %i resumed", get_num_by_target(target));
 108                         if (!t_con->suppress_prompt)
 109                                 telnet_prompt(connection);
 110                         break;
 111                 default:
 112                         break;
 113         }
 114
 115         return ERROR_OK;
 116 }
 117
 118 int telnet_new_connection(connection_t *connection)
 119 {
 120         telnet_connection_t *telnet_connection = malloc(sizeof(telnet_connection_t));
 121         telnet_service_t *telnet_service = connection->service->priv;
 122         int i;
 123
 124         connection->priv = telnet_connection;
 125
 126         /* initialize telnet connection information */
 127         telnet_connection->line_size = 0;
 128         telnet_connection->line_cursor = 0;
 129         telnet_connection->option_size = 0;
 130         telnet_connection->prompt = strdup("> ");
 131         telnet_connection->suppress_prompt = 0;
 132         telnet_connection->state = TELNET_STATE_DATA;
 133
 134         /* output goes through telnet connection */
 135         command_set_output_handler(connection->cmd_ctx, telnet_output, connection);
 136
 137         /* negotiate telnet options */
 138         write_socket(connection->fd, negotiate, strlen(negotiate));
 139
 140         /* print connection banner */
 141         if (telnet_service->banner)
 142         {
 143                 write_socket(connection->fd, telnet_service->banner, strlen(telnet_service->banner));
 144                 write_socket(connection->fd, "\r\n\0", 3);
 145         }
 146
 147         telnet_prompt(connection);
 148
 149         /* initialize history */
 150         for (i = 0; i < TELNET_LINE_HISTORY_SIZE; i++)
 151         {
 152                 telnet_connection->history[i] = NULL;
 153         }
 154         telnet_connection->next_history = 0;
 155         telnet_connection->current_history = 0;
 156
 157         target_register_event_callback(telnet_target_callback_event_handler, connection->cmd_ctx);
 158
 159         return ERROR_OK;
 160 }
 161
 162 void telnet_clear_line(connection_t *connection, telnet_connection_t *t_con)
 163 {
 164         /* move to end of line */
 165         if (t_con->line_cursor < t_con->line_size)
 166         {
 167                 write_socket(connection->fd, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor);
 168         }
 169
 170         /* backspace, overwrite with space, backspace */
 171         while (t_con->line_size > 0)
 172         {
 173                 write_socket(connection->fd, "\b \b", 3);
 174                 t_con->line_size--;
 175         }
 176         t_con->line_cursor = 0;
 177 }
 178
 179 int telnet_input(connection_t *connection)
 180 {
 181         int bytes_read;
 182         char buffer[TELNET_BUFFER_SIZE];
 183         char *buf_p;
 184         telnet_connection_t *t_con = connection->priv;
 185         command_context_t *command_context = connection->cmd_ctx;
 186
 187         bytes_read = read_socket(connection->fd, buffer, TELNET_BUFFER_SIZE);
 188
 189         if (bytes_read == 0)
 190                 return ERROR_SERVER_REMOTE_CLOSED;
 191         else if (bytes_read == -1)
 192         {
 193                 ERROR("error during read: %s", strerror(errno));
 194                 return ERROR_SERVER_REMOTE_CLOSED;
 195         }
 196
 197         buf_p = buffer;
 198         while (bytes_read)
 199         {
 200                 switch (t_con->state)
 201                 {
 202                         case TELNET_STATE_DATA:
 203                                 if (*buf_p == '\xff')
 204                                 {
 205                                         t_con->state = TELNET_STATE_IAC;
 206                                 }
 207                                 else
 208                                 {
 209                                         if (isprint(*buf_p)) /* printable character */
 210                                         {
 211                                                 write_socket(connection->fd, buf_p, 1);
 212                                                 if (t_con->line_cursor == t_con->line_size)
 213                                                 {
 214                                                         t_con->line[t_con->line_size++] = *buf_p;
 215                                                         t_con->line_cursor++;
 216                                                 }
 217                                                 else
 218                                                 {
 219                                                         int i;
 220                                                         memmove(t_con->line + t_con->line_cursor + 1, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor);
 221                                                         t_con->line[t_con->line_cursor++] = *buf_p;
 222                                                         t_con->line_size++;
 223                                                         write_socket(connection->fd, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor);
 224                                                         for (i = t_con->line_cursor; i < t_con->line_size; i++)
 225                                                         {
 226                                                                 write_socket(connection->fd, "\b", 1);
 227                                                         }
 228                                                 }
 229                                         }
 230                                         else /* non-printable */
 231                                         {
 232                                                 if (*buf_p == 0x1b) /* escape */
 233                                                 {
 234                                                         t_con->state = TELNET_STATE_ESCAPE;
 235                                                         t_con->last_escape = '\x00';
 236                                                 }
 237                                                 else if ((*buf_p == 0xd) || (*buf_p == 0xa)) /* CR/LF */
 238                                                 {
 239                                                         int retval;
 240
 241                                                         /* skip over combinations with CR/LF + NUL */
 242                                                         if (((*(buf_p + 1) == 0xa) || (*(buf_p + 1) == 0xd)) && (bytes_read > 1))
 243                                                         {
 244                                                                 buf_p++;
 245                                                                 bytes_read--;
 246                                                         }
 247                                                         if ((*(buf_p + 1) == 0) && (bytes_read > 1))
 248                                                         {
 249                                                                 buf_p++;
 250                                                                 bytes_read--;
 251                                                         }
 252                                                         t_con->line[t_con->line_size] = 0;
 253
 254                                                         write_socket(connection->fd, "\r\n\x00", 3);
 255
 256                                                         if (strcmp(t_con->line, "history") == 0)
 257                                                         {
 258                                                                 int i;
 259                                                                 for (i = 0; i < TELNET_LINE_HISTORY_SIZE; i++)
 260                                                                 {
 261                                                                         if (t_con->history[i])
 262                                                                         {
 263                                                                                 write_socket(connection->fd, t_con->history[i], strlen(t_con->history[i]));
 264                                                                                 write_socket(connection->fd, "\r\n\x00", 3);
 265                                                                         }
 266                                                                 }
 267                                                                 telnet_prompt(connection);
 268                                                                 t_con->line_size = 0;
 269                                                                 t_con->line_cursor = 0;
 270                                                                 continue;
 271                                                         }
 272
 273                                                         log_setCallback(telnet_log_callback, connection);
 274                                                         t_con->suppress_prompt = 1;
 275
 276                                                         if ((retval = command_run_line(command_context, t_con->line)) != ERROR_OK)
 277                                                         {
 278                                                                 if (retval == ERROR_COMMAND_CLOSE_CONNECTION)
 279                                                                 {
 280                                                                         return ERROR_SERVER_REMOTE_CLOSED;
 281                                                                 }
 282                                                         }
 283
 284                                                         t_con->suppress_prompt = 0;
 285
 286                                                         /* Save only non-blank lines in the history */
 287                                                         if (t_con->line_size > 0)
 288                                                         {
 289                                                                 /* if the history slot is already taken, free it */
 290                                                                 if (t_con->history[t_con->next_history])
 291                                                                 {
 292                                                                         free(t_con->history[t_con->next_history]);
 293                                                                 }
 294
 295                                                                 /* add line to history */
 296                                                                 t_con->history[t_con->next_history] = strdup(t_con->line);
 297
 298                                                                 /* wrap history at TELNET_LINE_HISTORY_SIZE */
 299                                                                 t_con->next_history = (t_con->next_history + 1) % TELNET_LINE_HISTORY_SIZE;
 300
 301                                                                 /* current history line starts at the new entry */
 302                                                                 t_con->current_history = t_con->next_history;
 303
 304                                                                 if (t_con->history[t_con->current_history])
 305                                                                 {
 306                                                                         free(t_con->history[t_con->current_history]);
 307                                                                 }
 308                                                                 t_con->history[t_con->current_history] = strdup("");
 309                                                         }
 310
 311                                                         /* output prompt after command */
 312                                                         telnet_prompt(connection);
 313
 314                                                         t_con->line_size = 0;
 315                                                         t_con->line_cursor = 0;
 316                                                 }
 317                                                 else if ((*buf_p == 0x7f) || (*buf_p == 0x8)) /* delete character */
 318                                                 {
 319                                                         if (t_con->line_cursor > 0)
 320                                                         {
 321                                                                 if (t_con->line_cursor != t_con->line_size)
 322                                                                 {
 323                                                                         int i;
 324                                                                         write_socket(connection->fd, "\b", 1);
 325                                                                         t_con->line_cursor--;
 326                                                                         t_con->line_size--;
 327                                                                         memmove(t_con->line + t_con->line_cursor, t_con->line + t_con->line_cursor + 1, t_con->line_size - t_con->line_cursor);
 328
 329                                                                         write_socket(connection->fd, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor);
 330                                                                         write_socket(connection->fd, " \b", 2);
 331                                                                         for (i = t_con->line_cursor; i < t_con->line_size; i++)
 332                                                                         {
 333                                                                                 write_socket(connection->fd, "\b", 1);
 334                                                                         }
 335                                                                 }
 336                                                                 else
 337                                                                 {
 338                                                                         t_con->line_size--;
 339                                                                         t_con->line_cursor--;
 340                                                                         /* back space: move the 'printer' head one char back, overwrite with space, move back again */
 341                                                                         write_socket(connection->fd, "\b \b", 3);
 342                                                                 }
 343                                                         }
 344                                                 }
 345                                                 else if (*buf_p == 0x15) /* clear line */
 346                                                 {
 347                                                         telnet_clear_line(connection, t_con);
 348                                                 }
 349                                                 else if (*buf_p == CTRL('B')) /* cursor left */
 350                                                 {
 351                                                         if (t_con->line_cursor > 0)
 352                                                         {
 353                                                                 write_socket(connection->fd, "\b", 1);
 354                                                                 t_con->line_cursor--;
 355                                                         }
 356                                                         t_con->state = TELNET_STATE_DATA;
 357                                                 }
 358                                                 else if (*buf_p == CTRL('F')) /* cursor right */
 359                                                 {
 360                                                         if (t_con->line_cursor < t_con->line_size)
 361                                                         {
 362                                                                 write_socket(connection->fd, t_con->line + t_con->line_cursor++, 1);
 363                                                         }
 364                                                         t_con->state = TELNET_STATE_DATA;
 365                                                 }
 366                                                 else
 367                                                 {
 368                                                         DEBUG("unhandled nonprintable: %2.2x", *buf_p);
 369                                                 }
 370                                         }
 371                                 }
 372                                 break;
 373                         case TELNET_STATE_IAC:
 374                                 switch (*buf_p)
 375                                 {
 376                                         case '\xfe':
 377                                                 t_con->state = TELNET_STATE_DONT;
 378                                                 break;
 379                                         case '\xfd':
 380                                                 t_con->state = TELNET_STATE_DO;
 381                                                 break;
 382                                         case '\xfc':
 383                                                 t_con->state = TELNET_STATE_WONT;
 384                                                 break;
 385                                         case '\xfb':
 386                                                 t_con->state = TELNET_STATE_WILL;
 387                                                 break;
 388                                 }
 389                                 break;
 390                         case TELNET_STATE_SB:
 391                                 break;
 392                         case TELNET_STATE_SE:
 393                                 break;
 394                         case TELNET_STATE_WILL:
 395                         case TELNET_STATE_WONT:
 396                         case TELNET_STATE_DO:
 397                         case TELNET_STATE_DONT:
 398                                 t_con->state = TELNET_STATE_DATA;
 399                                 break;
 400                         case TELNET_STATE_ESCAPE:
 401                                 if (t_con->last_escape == '[')
 402                                 {
 403                                         if (*buf_p == 'D') /* cursor left */
 404                                         {
 405                                                 if (t_con->line_cursor > 0)
 406                                                 {
 407                                                         write_socket(connection->fd, "\b", 1);
 408                                                         t_con->line_cursor--;
 409                                                 }
 410                                                 t_con->state = TELNET_STATE_DATA;
 411                                         }
 412                                         else if (*buf_p == 'C') /* cursor right */
 413                                         {
 414                                                 if (t_con->line_cursor < t_con->line_size)
 415                                                 {
 416                                                         write_socket(connection->fd, t_con->line + t_con->line_cursor++, 1);
 417                                                 }
 418                                                 t_con->state = TELNET_STATE_DATA;
 419                                         }
 420                                         else if (*buf_p == 'A') /* cursor up */
 421                                         {
 422                                                 int last_history = (t_con->current_history > 0) ? t_con->current_history - 1 : TELNET_LINE_HISTORY_SIZE-1;
 423                                                 if (t_con->history[last_history])
 424                                                 {
 425                                                         telnet_clear_line(connection, t_con);
 426                                                         t_con->line_size = strlen(t_con->history[last_history]);
 427                                                         t_con->line_cursor = t_con->line_size;
 428                                                         memcpy(t_con->line, t_con->history[last_history], t_con->line_size + 1);
 429                                                         write_socket(connection->fd, t_con->line, t_con->line_size);
 430                                                         t_con->current_history = last_history;
 431                                                 }
 432                                                 t_con->state = TELNET_STATE_DATA;
 433                                         }
 434                                         else if (*buf_p == 'B') /* cursor down */
 435                                         {
 436                                                 int next_history = (t_con->current_history + 1) % TELNET_LINE_HISTORY_SIZE;
 437                                                 if (t_con->history[next_history])
 438                                                 {
 439                                                         telnet_clear_line(connection, t_con);
 440                                                         t_con->line_size = strlen(t_con->history[next_history]);
 441                                                         t_con->line_cursor = t_con->line_size;
 442                                                         memcpy(t_con->line, t_con->history[next_history], t_con->line_size + 1);
 443                                                         write_socket(connection->fd, t_con->line, t_con->line_size);
 444                                                         t_con->current_history = next_history;
 445                                                 }
 446                                                 t_con->state = TELNET_STATE_DATA;
 447                                         }
 448                                         else if (*buf_p == '3')
 449                                         {
 450                                                 t_con->last_escape = *buf_p;
 451                                         }
 452                                         else
 453                                         {
 454                                                 t_con->state = TELNET_STATE_DATA;
 455                                         }
 456                                 }
 457                                 else if (t_con->last_escape == '3')
 458                                 {
 459                                         /* Remove character */
 460                                         if (*buf_p == '~')
 461                                         {
 462                                                 if (t_con->line_cursor < t_con->line_size)
 463                                                 {
 464                                                         int i;
 465                                                         t_con->line_size--;
 466                                                         /* remove char from line buffer */
 467                                                         memmove(t_con->line + t_con->line_cursor, t_con->line + t_con->line_cursor + 1, t_con->line_size - t_con->line_cursor);
 468
 469                                                         /* print remainder of buffer */
 470                                                         write_socket(connection->fd, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor);
 471                                                         /* overwrite last char with whitespace */
 472                                                         write_socket(connection->fd, " \b", 2);
 473
 474                                                         /* move back to cursor position*/
 475                                                         for (i = t_con->line_cursor; i < t_con->line_size; i++)
 476                                                         {
 477                                                                 write_socket(connection->fd, "\b", 1);
 478                                                         }
 479                                                 }
 480
 481                                                 t_con->state = TELNET_STATE_DATA;
 482                                         }
 483                                         else
 484                                         {
 485                                                 t_con->state = TELNET_STATE_DATA;
 486                                         }
 487                                 }
 488                                 else if (t_con->last_escape == '\x00')
 489                                 {
 490                                         if (*buf_p == '[')
 491                                         {
 492                                                 t_con->last_escape = *buf_p;
 493                                         }
 494                                         else
 495                                         {
 496                                                 t_con->state = TELNET_STATE_DATA;
 497                                         }
 498                                 }
 499                                 else
 500                                 {
 501                                         ERROR("BUG: unexpected value in t_con->last_escape");
 502                                         t_con->state = TELNET_STATE_DATA;
 503                                 }
 504
 505                                 break;
 506                         default:
 507                                 ERROR("unknown telnet state");
 508                                 exit(-1);
 509                 }
 510
 511                 bytes_read--;
 512                 buf_p++;
 513         }
 514
 515         return ERROR_OK;
 516 }
 517
 518 int telnet_connection_closed(connection_t *connection)
 519 {
 520         telnet_connection_t *t_con = connection->priv;
 521         int i;
 522
 523         if (t_con->prompt)
 524         {
 525                 free(t_con->prompt);
 526                 t_con->prompt = NULL;
 527         }
 528
 529         for (i = 0; i < TELNET_LINE_HISTORY_SIZE; i++)
 530         {
 531                 if (t_con->history[i])
 532                 {
 533                         free(t_con->history[i]);
 534                         t_con->history[i] = NULL;
 535                 }
 536         }
 537
 538         /* if this connection registered a debug-message receiver delete it */
 539         delete_debug_msg_receiver(connection->cmd_ctx, NULL);
 540
 541         if (connection->priv)
 542         {
 543                 free(connection->priv);
 544                 connection->priv = NULL;
 545         }
 546         else
 547         {
 548                 ERROR("BUG: connection->priv == NULL");
 549         }
 550
 551         target_unregister_event_callback(telnet_target_callback_event_handler, connection->cmd_ctx);
 552
 553         return ERROR_OK;
 554 }
 555
 556 int telnet_set_prompt(connection_t *connection, char *prompt)
 557 {
 558         telnet_connection_t *t_con = connection->priv;
 559
 560         t_con->prompt = strdup(prompt);
 561
 562         return ERROR_OK;
 563 }
 564
 565 int telnet_init(char *banner)
 566 {
 567         telnet_service_t *telnet_service = malloc(sizeof(telnet_service_t));
 568
 569         if (telnet_port == 0)
 570         {
 571                 WARNING("no telnet port specified, using default port 4444");
 572                 telnet_port = 4444;
 573         }
 574
 575         telnet_service->banner = banner;
 576
 577         add_service("telnet", CONNECTION_TELNET, telnet_port, 1, telnet_new_connection, telnet_input, telnet_connection_closed, telnet_service);
 578
 579         return ERROR_OK;
 580 }
 581
 582 int telnet_register_commands(command_context_t *command_context)
 583 {
 584         register_command(command_context, NULL, "exit", handle_exit_command,
 585                                          COMMAND_EXEC, "exit telnet session");
 586
 587         register_command(command_context, NULL, "telnet_port", handle_telnet_port_command,
 588                                          COMMAND_CONFIG, "");
 589
 590         return ERROR_OK;
 591 }
 592
 593 /* daemon configuration command telnet_port */
 594 int handle_telnet_port_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc)
 595 {
 596         if (argc == 0)
 597                 return ERROR_OK;
 598
 599         /* only if the port wasn't overwritten by cmdline */
 600         if (telnet_port == 0)
 601                 telnet_port = strtoul(args[0], NULL, 0);
 602
 603         return ERROR_OK;
 604 }
 605
 606 int handle_exit_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc)
 607 {
 608         return ERROR_COMMAND_CLOSE_CONNECTION;
 609 }