641 lines
18 KiB
C
641 lines
18 KiB
C
/***************************************************************************
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* Copyright (C) 2005 by Dominic Rath *
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* Dominic.Rath@gmx.de *
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* *
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* Copyright (C) 2007,2008 Øyvind Harboe *
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* oyvind.harboe@zylin.com *
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* *
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* Copyright (C) 2008 by Spencer Oliver *
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* spen@spen-soft.co.uk *
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* *
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* This program is free software; you can redistribute it and/or modify *
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* it under the terms of the GNU General Public License as published by *
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* the Free Software Foundation; either version 2 of the License, or *
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* (at your option) any later version. *
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* *
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* This program is distributed in the hope that it will be useful, *
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* but WITHOUT ANY WARRANTY; without even the implied warranty of *
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
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* GNU General Public License for more details. *
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* *
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* You should have received a copy of the GNU General Public License *
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* along with this program; if not, write to the *
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* Free Software Foundation, Inc., *
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* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. *
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***************************************************************************/
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include "telnet_server.h"
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#include <target/target_request.h>
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static unsigned short telnet_port = 4444;
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static char *negotiate =
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"\xFF\xFB\x03" /* IAC WILL Suppress Go Ahead */
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"\xFF\xFB\x01" /* IAC WILL Echo */
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"\xFF\xFD\x03" /* IAC DO Suppress Go Ahead */
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"\xFF\xFE\x01"; /* IAC DON'T Echo */
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#define CTRL(c) (c - '@')
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/* The only way we can detect that the socket is closed is the first time
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* we write to it, we will fail. Subsequent write operations will
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* succeed. Shudder!
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*/
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int telnet_write(struct connection *connection, const void *data, int len)
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{
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struct telnet_connection *t_con = connection->priv;
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if (t_con->closed)
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return ERROR_SERVER_REMOTE_CLOSED;
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if (write_socket(connection->fd, data, len) == len)
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{
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return ERROR_OK;
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}
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t_con->closed = 1;
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return ERROR_SERVER_REMOTE_CLOSED;
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}
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int telnet_prompt(struct connection *connection)
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{
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struct telnet_connection *t_con = connection->priv;
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telnet_write(connection, "\r", 1); /* the prompt is always placed at the line beginning */
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return telnet_write(connection, t_con->prompt, strlen(t_con->prompt));
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}
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int telnet_outputline(struct connection *connection, const char *line)
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{
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int len;
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/* process lines in buffer */
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while (*line) {
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char *line_end = strchr(line, '\n');
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if (line_end)
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len = line_end-line;
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else
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len = strlen(line);
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telnet_write(connection, line, len);
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if (line_end)
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{
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telnet_write(connection, "\r\n", 2);
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line += len + 1;
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}
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else
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{
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line += len;
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}
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}
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return ERROR_OK;
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}
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int telnet_output(struct command_context *cmd_ctx, const char* line)
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{
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struct connection *connection = cmd_ctx->output_handler_priv;
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return telnet_outputline(connection, line);
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}
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void telnet_log_callback(void *priv, const char *file, unsigned line,
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const char *function, const char *string)
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{
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struct connection *connection = priv;
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struct telnet_connection *t_con = connection->priv;
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int i;
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/* if there is no prompt, simply output the message */
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if (t_con->line_cursor < 0)
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{
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telnet_outputline(connection, string);
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return;
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}
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/* clear the command line */
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telnet_write(connection, "\r", 1);
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for (i = strlen(t_con->prompt) + t_con->line_size; i > 0; i -= 16)
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telnet_write(connection, " ", i > 16 ? 16 : i);
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telnet_write(connection, "\r", 1);
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/* output the message */
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telnet_outputline(connection, string);
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/* put the command line to its previous state */
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telnet_prompt(connection);
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telnet_write(connection, t_con->line, t_con->line_size);
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for (i = t_con->line_size; i > t_con->line_cursor; i--)
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telnet_write(connection, "\b", 1);
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}
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int telnet_new_connection(struct connection *connection)
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{
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struct telnet_connection *telnet_connection = malloc(sizeof(struct telnet_connection));
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struct telnet_service *telnet_service = connection->service->priv;
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int i;
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connection->priv = telnet_connection;
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/* initialize telnet connection information */
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telnet_connection->closed = 0;
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telnet_connection->line_size = 0;
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telnet_connection->line_cursor = 0;
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telnet_connection->option_size = 0;
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telnet_connection->prompt = strdup("> ");
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telnet_connection->state = TELNET_STATE_DATA;
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/* output goes through telnet connection */
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command_set_output_handler(connection->cmd_ctx, telnet_output, connection);
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/* negotiate telnet options */
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telnet_write(connection, negotiate, strlen(negotiate));
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/* print connection banner */
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if (telnet_service->banner)
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{
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telnet_write(connection, telnet_service->banner, strlen(telnet_service->banner));
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telnet_write(connection, "\r\n", 2);
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}
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telnet_prompt(connection);
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/* initialize history */
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for (i = 0; i < TELNET_LINE_HISTORY_SIZE; i++)
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{
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telnet_connection->history[i] = NULL;
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}
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telnet_connection->next_history = 0;
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telnet_connection->current_history = 0;
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log_add_callback(telnet_log_callback, connection);
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return ERROR_OK;
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}
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void telnet_clear_line(struct connection *connection, struct telnet_connection *t_con)
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{
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/* move to end of line */
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if (t_con->line_cursor < t_con->line_size)
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{
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telnet_write(connection, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor);
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}
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/* backspace, overwrite with space, backspace */
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while (t_con->line_size > 0)
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{
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telnet_write(connection, "\b \b", 3);
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t_con->line_size--;
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}
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t_con->line_cursor = 0;
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}
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int telnet_input(struct connection *connection)
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{
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int bytes_read;
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unsigned char buffer[TELNET_BUFFER_SIZE];
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unsigned char *buf_p;
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struct telnet_connection *t_con = connection->priv;
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struct command_context *command_context = connection->cmd_ctx;
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bytes_read = read_socket(connection->fd, buffer, TELNET_BUFFER_SIZE);
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if (bytes_read == 0)
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return ERROR_SERVER_REMOTE_CLOSED;
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else if (bytes_read == -1)
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{
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LOG_ERROR("error during read: %s", strerror(errno));
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return ERROR_SERVER_REMOTE_CLOSED;
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}
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buf_p = buffer;
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while (bytes_read)
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{
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switch (t_con->state)
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{
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case TELNET_STATE_DATA:
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if (*buf_p == 0xff)
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{
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t_con->state = TELNET_STATE_IAC;
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}
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else
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{
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if (isprint(*buf_p)) /* printable character */
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{
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/* watch buffer size leaving one spare character for string null termination */
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if (t_con->line_size == TELNET_LINE_MAX_SIZE-1)
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{
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/* output audible bell if buffer is full */
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telnet_write(connection, "\x07", 1); /* "\a" does not work, at least on windows */
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}
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else if (t_con->line_cursor == t_con->line_size)
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{
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telnet_write(connection, buf_p, 1);
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t_con->line[t_con->line_size++] = *buf_p;
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t_con->line_cursor++;
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}
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else
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{
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int i;
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memmove(t_con->line + t_con->line_cursor + 1, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor);
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t_con->line[t_con->line_cursor] = *buf_p;
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t_con->line_size++;
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telnet_write(connection, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor);
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t_con->line_cursor++;
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for (i = t_con->line_cursor; i < t_con->line_size; i++)
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{
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telnet_write(connection, "\b", 1);
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}
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}
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}
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else /* non-printable */
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{
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if (*buf_p == 0x1b) /* escape */
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{
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t_con->state = TELNET_STATE_ESCAPE;
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t_con->last_escape = '\x00';
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}
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else if ((*buf_p == 0xd) || (*buf_p == 0xa)) /* CR/LF */
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{
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int retval;
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/* skip over combinations with CR/LF and NUL characters */
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if ((bytes_read > 1) && ((*(buf_p + 1) == 0xa) || (*(buf_p + 1) == 0xd)))
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{
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buf_p++;
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bytes_read--;
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}
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if ((bytes_read > 1) && (*(buf_p + 1) == 0))
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{
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buf_p++;
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bytes_read--;
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}
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t_con->line[t_con->line_size] = 0;
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telnet_write(connection, "\r\n\x00", 3);
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if (strcmp(t_con->line, "history") == 0)
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{
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int i;
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for (i = 1; i < TELNET_LINE_HISTORY_SIZE; i++)
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{
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/* the t_con->next_history line contains empty string (unless NULL), thus it is not printed */
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char *history_line = t_con->history[(t_con->next_history + i) % TELNET_LINE_HISTORY_SIZE];
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if (history_line)
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{
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telnet_write(connection, history_line, strlen(history_line));
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telnet_write(connection, "\r\n\x00", 3);
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}
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}
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t_con->line_size = 0;
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t_con->line_cursor = 0;
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continue;
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}
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/* save only non-blank not repeating lines in the history */
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char *prev_line = t_con->history[(t_con->current_history > 0) ? t_con->current_history - 1 : TELNET_LINE_HISTORY_SIZE-1];
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if (*t_con->line && (prev_line == NULL || strcmp(t_con->line, prev_line)))
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{
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/* if the history slot is already taken, free it */
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if (t_con->history[t_con->next_history])
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{
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free(t_con->history[t_con->next_history]);
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}
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/* add line to history */
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t_con->history[t_con->next_history] = strdup(t_con->line);
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/* wrap history at TELNET_LINE_HISTORY_SIZE */
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t_con->next_history = (t_con->next_history + 1) % TELNET_LINE_HISTORY_SIZE;
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/* current history line starts at the new entry */
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t_con->current_history = t_con->next_history;
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if (t_con->history[t_con->current_history])
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{
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free(t_con->history[t_con->current_history]);
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}
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t_con->history[t_con->current_history] = strdup("");
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}
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t_con->line_size = 0;
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t_con->line_cursor = -1; /* to supress prompt in log callback during command execution */
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retval = command_run_line(command_context, t_con->line);
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t_con->line_cursor = 0;
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if (retval == ERROR_COMMAND_CLOSE_CONNECTION)
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return ERROR_SERVER_REMOTE_CLOSED;
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retval = telnet_prompt(connection);
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if (retval == ERROR_SERVER_REMOTE_CLOSED)
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return ERROR_SERVER_REMOTE_CLOSED;
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}
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else if ((*buf_p == 0x7f) || (*buf_p == 0x8)) /* delete character */
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{
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if (t_con->line_cursor > 0)
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{
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if (t_con->line_cursor != t_con->line_size)
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{
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int i;
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telnet_write(connection, "\b", 1);
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t_con->line_cursor--;
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t_con->line_size--;
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memmove(t_con->line + t_con->line_cursor, t_con->line + t_con->line_cursor + 1, t_con->line_size - t_con->line_cursor);
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telnet_write(connection, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor);
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telnet_write(connection, " \b", 2);
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for (i = t_con->line_cursor; i < t_con->line_size; i++)
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{
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telnet_write(connection, "\b", 1);
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}
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}
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else
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{
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t_con->line_size--;
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t_con->line_cursor--;
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/* back space: move the 'printer' head one char back, overwrite with space, move back again */
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telnet_write(connection, "\b \b", 3);
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}
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}
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}
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else if (*buf_p == 0x15) /* clear line */
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{
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telnet_clear_line(connection, t_con);
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}
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else if (*buf_p == CTRL('B')) /* cursor left */
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{
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if (t_con->line_cursor > 0)
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{
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telnet_write(connection, "\b", 1);
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t_con->line_cursor--;
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}
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t_con->state = TELNET_STATE_DATA;
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}
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else if (*buf_p == CTRL('F')) /* cursor right */
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{
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if (t_con->line_cursor < t_con->line_size)
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{
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telnet_write(connection, t_con->line + t_con->line_cursor++, 1);
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}
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t_con->state = TELNET_STATE_DATA;
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}
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else
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{
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LOG_DEBUG("unhandled nonprintable: %2.2x", *buf_p);
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}
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}
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}
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break;
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case TELNET_STATE_IAC:
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switch (*buf_p)
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{
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case 0xfe:
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t_con->state = TELNET_STATE_DONT;
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break;
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case 0xfd:
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t_con->state = TELNET_STATE_DO;
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break;
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case 0xfc:
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t_con->state = TELNET_STATE_WONT;
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break;
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case 0xfb:
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t_con->state = TELNET_STATE_WILL;
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break;
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}
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break;
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case TELNET_STATE_SB:
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break;
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case TELNET_STATE_SE:
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break;
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case TELNET_STATE_WILL:
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case TELNET_STATE_WONT:
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case TELNET_STATE_DO:
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case TELNET_STATE_DONT:
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t_con->state = TELNET_STATE_DATA;
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break;
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case TELNET_STATE_ESCAPE:
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if (t_con->last_escape == '[')
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{
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if (*buf_p == 'D') /* cursor left */
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{
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if (t_con->line_cursor > 0)
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{
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telnet_write(connection, "\b", 1);
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t_con->line_cursor--;
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}
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t_con->state = TELNET_STATE_DATA;
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}
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else if (*buf_p == 'C') /* cursor right */
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{
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if (t_con->line_cursor < t_con->line_size)
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{
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telnet_write(connection, t_con->line + t_con->line_cursor++, 1);
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}
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t_con->state = TELNET_STATE_DATA;
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}
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else if (*buf_p == 'A') /* cursor up */
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{
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int last_history = (t_con->current_history > 0) ? t_con->current_history - 1 : TELNET_LINE_HISTORY_SIZE-1;
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if (t_con->history[last_history])
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{
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telnet_clear_line(connection, t_con);
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t_con->line_size = strlen(t_con->history[last_history]);
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t_con->line_cursor = t_con->line_size;
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memcpy(t_con->line, t_con->history[last_history], t_con->line_size);
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telnet_write(connection, t_con->line, t_con->line_size);
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t_con->current_history = last_history;
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}
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t_con->state = TELNET_STATE_DATA;
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}
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else if (*buf_p == 'B') /* cursor down */
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{
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int next_history = (t_con->current_history + 1) % TELNET_LINE_HISTORY_SIZE;
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if (t_con->history[next_history])
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{
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telnet_clear_line(connection, t_con);
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t_con->line_size = strlen(t_con->history[next_history]);
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t_con->line_cursor = t_con->line_size;
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memcpy(t_con->line, t_con->history[next_history], t_con->line_size);
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telnet_write(connection, t_con->line, t_con->line_size);
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t_con->current_history = next_history;
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}
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t_con->state = TELNET_STATE_DATA;
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}
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else if (*buf_p == '3')
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{
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t_con->last_escape = *buf_p;
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}
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else
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{
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t_con->state = TELNET_STATE_DATA;
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}
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}
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else if (t_con->last_escape == '3')
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{
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/* Remove character */
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if (*buf_p == '~')
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{
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if (t_con->line_cursor < t_con->line_size)
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{
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int i;
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t_con->line_size--;
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/* remove char from line buffer */
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memmove(t_con->line + t_con->line_cursor, t_con->line + t_con->line_cursor + 1, t_con->line_size - t_con->line_cursor);
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/* print remainder of buffer */
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telnet_write(connection, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor);
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/* overwrite last char with whitespace */
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telnet_write(connection, " \b", 2);
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/* move back to cursor position*/
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for (i = t_con->line_cursor; i < t_con->line_size; i++)
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{
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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");
|
|
exit(-1);
|
|
}
|
|
|
|
bytes_read--;
|
|
buf_p++;
|
|
}
|
|
|
|
return ERROR_OK;
|
|
}
|
|
|
|
int telnet_connection_closed(struct connection *connection)
|
|
{
|
|
struct telnet_connection *t_con = connection->priv;
|
|
int i;
|
|
|
|
log_remove_callback(telnet_log_callback, connection);
|
|
|
|
if (t_con->prompt)
|
|
{
|
|
free(t_con->prompt);
|
|
t_con->prompt = NULL;
|
|
}
|
|
|
|
for (i = 0; i < TELNET_LINE_HISTORY_SIZE; i++)
|
|
{
|
|
if (t_con->history[i])
|
|
{
|
|
free(t_con->history[i]);
|
|
t_con->history[i] = NULL;
|
|
}
|
|
}
|
|
|
|
/* if this connection registered a debug-message receiver delete it */
|
|
delete_debug_msg_receiver(connection->cmd_ctx, NULL);
|
|
|
|
if (connection->priv)
|
|
{
|
|
free(connection->priv);
|
|
connection->priv = NULL;
|
|
}
|
|
else
|
|
{
|
|
LOG_ERROR("BUG: connection->priv == NULL");
|
|
}
|
|
|
|
return ERROR_OK;
|
|
}
|
|
|
|
int telnet_set_prompt(struct connection *connection, char *prompt)
|
|
{
|
|
struct telnet_connection *t_con = connection->priv;
|
|
|
|
if (t_con->prompt != NULL)
|
|
free(t_con->prompt);
|
|
|
|
t_con->prompt = strdup(prompt);
|
|
|
|
return ERROR_OK;
|
|
}
|
|
|
|
int telnet_init(char *banner)
|
|
{
|
|
struct telnet_service *telnet_service = malloc(sizeof(struct telnet_service));
|
|
|
|
if (telnet_port == 0)
|
|
{
|
|
LOG_INFO("telnet port disabled");
|
|
free(telnet_service);
|
|
return ERROR_OK;
|
|
}
|
|
|
|
telnet_service->banner = banner;
|
|
|
|
add_service("telnet", CONNECTION_TCP, telnet_port, 1, telnet_new_connection, telnet_input, telnet_connection_closed, telnet_service);
|
|
|
|
return ERROR_OK;
|
|
}
|
|
|
|
/* daemon configuration command telnet_port */
|
|
COMMAND_HANDLER(handle_telnet_port_command)
|
|
{
|
|
return CALL_COMMAND_HANDLER(server_port_command, &telnet_port);
|
|
}
|
|
|
|
COMMAND_HANDLER(handle_exit_command)
|
|
{
|
|
return ERROR_COMMAND_CLOSE_CONNECTION;
|
|
}
|
|
|
|
static const struct command_registration telnet_command_handlers[] = {
|
|
{
|
|
.name = "exit",
|
|
.handler = &handle_exit_command,
|
|
.mode = COMMAND_EXEC,
|
|
.help = "exit telnet session",
|
|
},
|
|
{
|
|
.name = "telnet_port",
|
|
.handler = &handle_telnet_port_command,
|
|
.mode = COMMAND_ANY,
|
|
.help = "port on which to listen "
|
|
"for incoming telnet connections",
|
|
.usage = "<port>",
|
|
},
|
|
COMMAND_REGISTRATION_DONE
|
|
};
|
|
|
|
int telnet_register_commands(struct command_context *cmd_ctx)
|
|
{
|
|
return register_commands(cmd_ctx, NULL, telnet_command_handlers);
|
|
}
|