static void telnet_log_callback(void *priv, const char *file, unsigned line, const char *function, const char *string) { struct connection *connection = priv; struct telnet_connection *t_con = connection->priv; int i; /* if there is no prompt, simply output the message */ if (t_con->line_cursor < 0) { telnet_outputline(connection, string); return; } /* clear the command line */ for (i = strlen(t_con->prompt) + t_con->line_size; i > 0; i -= 16) telnet_write(connection, "\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b", i > 16 ? 16 : i); for (i = strlen(t_con->prompt) + t_con->line_size; i > 0; i -= 16) telnet_write(connection, " ", i > 16 ? 16 : i); for (i = strlen(t_con->prompt) + t_con->line_size; i > 0; i -= 16) telnet_write(connection, "\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b", i > 16 ? 16 : i); /* output the message */ telnet_outputline(connection, string); /* put the command line to its previous state */ telnet_prompt(connection); telnet_write(connection, t_con->line, t_con->line_size); for (i = t_con->line_size; i > t_con->line_cursor; i--) telnet_write(connection, "\b", 1); }
static int telnet_new_connection(struct connection *connection) { struct telnet_connection *telnet_connection; struct telnet_service *telnet_service = connection->service->priv; int i; telnet_connection = malloc(sizeof(struct telnet_connection)); if (!telnet_connection) { LOG_ERROR("Failed to allocate telnet connection."); return ERROR_FAIL; } connection->priv = telnet_connection; /* initialize telnet connection information */ telnet_connection->closed = 0; telnet_connection->line_size = 0; telnet_connection->line_cursor = 0; telnet_connection->option_size = 0; telnet_connection->prompt = strdup("> "); telnet_connection->state = TELNET_STATE_DATA; /* output goes through telnet connection */ command_set_output_handler(connection->cmd_ctx, telnet_output, connection); /* negotiate telnet options */ telnet_write(connection, negotiate, strlen(negotiate)); /* print connection banner */ if (telnet_service->banner) { telnet_write(connection, telnet_service->banner, strlen(telnet_service->banner)); telnet_write(connection, "\r\n", 2); } /* the prompt is always placed at the line beginning */ telnet_write(connection, "\r", 1); telnet_prompt(connection); /* initialize history */ for (i = 0; i < TELNET_LINE_HISTORY_SIZE; i++) telnet_connection->history[i] = NULL; telnet_connection->next_history = 0; telnet_connection->current_history = 0; telnet_load_history(telnet_connection); log_add_callback(telnet_log_callback, connection); return ERROR_OK; }
static void telnet_log_callback(void *priv, const char *file, unsigned line, const char *function, const char *string) { struct connection *connection = priv; struct telnet_connection *t_con = connection->priv; size_t i; size_t tmp; /* If the prompt is not visible, simply output the message. */ if (!t_con->prompt_visible) { telnet_outputline(connection, string); return; } /* Clear the command line. */ tmp = strlen(t_con->prompt) + t_con->line_size; for (i = 0; i < tmp; i += 16) telnet_write(connection, "\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b", MIN(tmp - i, 16)); for (i = 0; i < tmp; i += 16) telnet_write(connection, " ", MIN(tmp - i, 16)); for (i = 0; i < tmp; i += 16) telnet_write(connection, "\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b", MIN(tmp - i, 16)); telnet_outputline(connection, string); /* Put the command line to its previous state. */ telnet_prompt(connection); telnet_write(connection, t_con->line, t_con->line_size); for (i = t_con->line_cursor; i < t_con->line_size; i++) telnet_write(connection, "\b", 1); }
static int telnet_input(struct connection *connection) { int bytes_read; unsigned char buffer[TELNET_BUFFER_SIZE]; unsigned char *buf_p; struct telnet_connection *t_con = connection->priv; struct command_context *command_context = connection->cmd_ctx; bytes_read = connection_read(connection, buffer, TELNET_BUFFER_SIZE); if (bytes_read == 0) return ERROR_SERVER_REMOTE_CLOSED; else if (bytes_read == -1) { LOG_ERROR("error during read: %s", strerror(errno)); return ERROR_SERVER_REMOTE_CLOSED; } buf_p = buffer; while (bytes_read) { switch (t_con->state) { case TELNET_STATE_DATA: if (*buf_p == 0xff) t_con->state = TELNET_STATE_IAC; else { if (isprint(*buf_p)) { /* printable character */ /* watch buffer size leaving one spare character for * string null termination */ if (t_con->line_size == TELNET_LINE_MAX_SIZE-1) { /* output audible bell if buffer is full * "\a" does not work, at least on windows */ telnet_write(connection, "\x07", 1); } else if (t_con->line_cursor == t_con->line_size) { telnet_write(connection, buf_p, 1); t_con->line[t_con->line_size++] = *buf_p; t_con->line_cursor++; } else { int i; memmove(t_con->line + t_con->line_cursor + 1, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor); t_con->line[t_con->line_cursor] = *buf_p; t_con->line_size++; telnet_write(connection, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor); t_con->line_cursor++; for (i = t_con->line_cursor; i < t_con->line_size; i++) telnet_write(connection, "\b", 1); } } else { /* non-printable */ if (*buf_p == 0x1b) { /* escape */ t_con->state = TELNET_STATE_ESCAPE; t_con->last_escape = '\x00'; } else if ((*buf_p == 0xd) || (*buf_p == 0xa)) { /* CR/LF */ int retval; /* skip over combinations with CR/LF and NUL characters */ if ((bytes_read > 1) && ((*(buf_p + 1) == 0xa) || (*(buf_p + 1) == 0xd))) { buf_p++; bytes_read--; } if ((bytes_read > 1) && (*(buf_p + 1) == 0)) { buf_p++; bytes_read--; } t_con->line[t_con->line_size] = 0; telnet_write(connection, "\r\n\x00", 3); if (strcmp(t_con->line, "history") == 0) { int i; for (i = 1; i < TELNET_LINE_HISTORY_SIZE; i++) { /* the t_con->next_history line contains empty string * (unless NULL), thus it is not printed */ char *history_line = t_con->history[(t_con-> next_history + i) % TELNET_LINE_HISTORY_SIZE]; if (history_line) { telnet_write(connection, history_line, strlen(history_line)); telnet_write(connection, "\r\n\x00", 3); } } t_con->line_size = 0; t_con->line_cursor = 0; continue; } /* save only non-blank not repeating lines in the history */ char *prev_line = t_con->history[(t_con->current_history > 0) ? t_con->current_history - 1 : TELNET_LINE_HISTORY_SIZE-1]; if (*t_con->line && (prev_line == NULL || strcmp(t_con->line, prev_line))) { /* if the history slot is already taken, free it */ if (t_con->history[t_con->next_history]) free(t_con->history[t_con->next_history]); /* add line to history */ t_con->history[t_con->next_history] = strdup(t_con->line); /* wrap history at TELNET_LINE_HISTORY_SIZE */ t_con->next_history = (t_con->next_history + 1) % TELNET_LINE_HISTORY_SIZE; /* current history line starts at the new entry */ t_con->current_history = t_con->next_history; if (t_con->history[t_con->current_history]) free(t_con->history[t_con->current_history]); t_con->history[t_con->current_history] = strdup(""); } t_con->line_size = 0; /* to suppress prompt in log callback during command execution */ t_con->line_cursor = -1; if (strcmp(t_con->line, "shutdown") == 0) telnet_save_history(t_con); retval = command_run_line(command_context, t_con->line); t_con->line_cursor = 0; if (retval == ERROR_COMMAND_CLOSE_CONNECTION) return ERROR_SERVER_REMOTE_CLOSED; /* the prompt is always * placed at the line beginning */ telnet_write(connection, "\r", 1); retval = telnet_prompt(connection); if (retval == ERROR_SERVER_REMOTE_CLOSED) return ERROR_SERVER_REMOTE_CLOSED; } else if ((*buf_p == 0x7f) || (*buf_p == 0x8)) { /* delete character */ if (t_con->line_cursor > 0) { if (t_con->line_cursor != t_con->line_size) { int i; telnet_write(connection, "\b", 1); t_con->line_cursor--; t_con->line_size--; memmove(t_con->line + t_con->line_cursor, t_con->line + t_con->line_cursor + 1, t_con->line_size - t_con->line_cursor); telnet_write(connection, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor); telnet_write(connection, " \b", 2); for (i = t_con->line_cursor; i < t_con->line_size; i++) telnet_write(connection, "\b", 1); } else { t_con->line_size--; t_con->line_cursor--; /* back space: move the 'printer' head one char * back, overwrite with space, move back again */ telnet_write(connection, "\b \b", 3); } } } else if (*buf_p == 0x15) /* clear line */ telnet_clear_line(connection, t_con); else if (*buf_p == CTRL('B')) { /* cursor left */ if (t_con->line_cursor > 0) { telnet_write(connection, "\b", 1); t_con->line_cursor--; } t_con->state = TELNET_STATE_DATA; } else if (*buf_p == CTRL('F')) { /* cursor right */ if (t_con->line_cursor < t_con->line_size) telnet_write(connection, t_con->line + t_con->line_cursor++, 1); t_con->state = TELNET_STATE_DATA; } else if (*buf_p == CTRL('P')) /* cursor up */ telnet_history_up(connection); else if (*buf_p == CTRL('N')) /* cursor down */ telnet_history_down(connection); else LOG_DEBUG("unhandled nonprintable: %2.2x", *buf_p); } } break; case TELNET_STATE_IAC: switch (*buf_p) { case 0xfe: t_con->state = TELNET_STATE_DONT; break; case 0xfd: t_con->state = TELNET_STATE_DO; break; case 0xfc: t_con->state = TELNET_STATE_WONT; break; case 0xfb: t_con->state = TELNET_STATE_WILL; break; } break; case TELNET_STATE_SB: break; case TELNET_STATE_SE: break; case TELNET_STATE_WILL: case TELNET_STATE_WONT: case TELNET_STATE_DO: case TELNET_STATE_DONT: t_con->state = TELNET_STATE_DATA; break; case TELNET_STATE_ESCAPE: if (t_con->last_escape == '[') { if (*buf_p == 'D') { /* cursor left */ if (t_con->line_cursor > 0) { telnet_write(connection, "\b", 1); t_con->line_cursor--; } t_con->state = TELNET_STATE_DATA; } else if (*buf_p == 'C') { /* cursor right */ if (t_con->line_cursor < t_con->line_size) telnet_write(connection, t_con->line + t_con->line_cursor++, 1); t_con->state = TELNET_STATE_DATA; } else if (*buf_p == 'A') { /* cursor up */ telnet_history_up(connection); } else if (*buf_p == 'B') { /* cursor down */ telnet_history_down(connection); } else if (*buf_p == '3') t_con->last_escape = *buf_p; else t_con->state = TELNET_STATE_DATA; } else if (t_con->last_escape == '3') { /* Remove character */ if (*buf_p == '~') { if (t_con->line_cursor < t_con->line_size) { int i; t_con->line_size--; /* remove char from line buffer */ memmove(t_con->line + t_con->line_cursor, t_con->line + t_con->line_cursor + 1, t_con->line_size - t_con->line_cursor); /* print remainder of buffer */ telnet_write(connection, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor); /* overwrite last char with whitespace */ telnet_write(connection, " \b", 2); /* move back to cursor position*/ for (i = t_con->line_cursor; i < t_con->line_size; i++) telnet_write(connection, "\b", 1); } t_con->state = TELNET_STATE_DATA; } else t_con->state = TELNET_STATE_DATA; } else if (t_con->last_escape == '\x00') { if (*buf_p == '[') t_con->last_escape = *buf_p; else t_con->state = TELNET_STATE_DATA; } else { LOG_ERROR("BUG: unexpected value in t_con->last_escape"); t_con->state = TELNET_STATE_DATA; } break; default: LOG_ERROR("unknown telnet state"); return ERROR_FAIL; } bytes_read--; buf_p++; } return ERROR_OK; }