571 lines
16 KiB
C
571 lines
16 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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* 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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#include "telnet_server.h"
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#include "server.h"
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#include "log.h"
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#include "command.h"
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#include "target.h"
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#include <stdlib.h>
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#include <unistd.h>
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#include <errno.h>
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#include <string.h>
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#include <ctype.h>
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static unsigned short telnet_port = 0;
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int handle_exit_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc);
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int handle_telnet_port_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc);
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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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void telnet_prompt(connection_t *connection)
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{
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telnet_connection_t *t_con = connection->priv;
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write(connection->fd, t_con->prompt, strlen(t_con->prompt));
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}
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int telnet_output(struct command_context_s *cmd_ctx, char* line)
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{
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connection_t *connection = cmd_ctx->output_handler_priv;
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write(connection->fd, line, strlen(line));
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write(connection->fd, "\r\n\0", 3);
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return ERROR_OK;
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}
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int telnet_target_callback_event_handler(struct target_s *target, enum target_event event, void *priv)
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{
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struct command_context_s *cmd_ctx = priv;
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connection_t *connection = cmd_ctx->output_handler_priv;
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telnet_connection_t *t_con = connection->priv;
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char buffer[512];
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switch (event)
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{
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case TARGET_EVENT_HALTED:
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command_print(cmd_ctx, "Target %i halted", get_num_by_target(target));
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target->type->arch_state(target, buffer, 512);
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buffer[511] = 0;
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command_print(cmd_ctx, "%s", buffer);
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telnet_prompt(connection);
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t_con->surpress_prompt = 1;
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break;
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case TARGET_EVENT_RESUMED:
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command_print(cmd_ctx, "Target %i resumed", get_num_by_target(target));
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telnet_prompt(connection);
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t_con->surpress_prompt = 1;
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break;
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default:
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break;
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}
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return ERROR_OK;
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}
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int telnet_new_connection(connection_t *connection)
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{
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telnet_connection_t *telnet_connection = malloc(sizeof(telnet_connection_t));
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telnet_service_t *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->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->surpress_prompt = 0;
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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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write(connection->fd, 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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write(connection->fd, telnet_service->banner, strlen(telnet_service->banner));
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write(connection->fd, "\r\n\0", 3);
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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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target_register_event_callback(telnet_target_callback_event_handler, connection->cmd_ctx);
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return ERROR_OK;
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}
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void telnet_clear_line(connection_t *connection, telnet_connection_t *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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write(connection->fd, 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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write(connection->fd, "\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(connection_t *connection)
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{
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int bytes_read;
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char buffer[TELNET_BUFFER_SIZE];
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char *buf_p;
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telnet_connection_t *t_con = connection->priv;
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command_context_t *command_context = connection->cmd_ctx;
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bytes_read = read(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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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 == '\xff')
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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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write(connection->fd, buf_p, 1);
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if (t_con->line_cursor == t_con->line_size)
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{
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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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write(connection->fd, t_con->line + t_con->line_cursor, t_con->line_size - 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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write(connection->fd, "\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 + NUL */
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if (((*(buf_p + 1) == 0xa) || (*(buf_p + 1) == 0xd)) && (bytes_read > 1))
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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 ((*(buf_p + 1) == 0) && (bytes_read > 1))
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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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write(connection->fd, "\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 = 0; i < TELNET_LINE_HISTORY_SIZE; i++)
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{
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if (t_con->history[i])
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{
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write(connection->fd, t_con->history[i], strlen(t_con->history[i]));
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write(connection->fd, "\r\n\x00", 3);
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}
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}
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telnet_prompt(connection);
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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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/* we're running a command, so we need a prompt
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* if the output handler is called, this gets set again */
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t_con->surpress_prompt = 0;
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if ((retval = command_run_line(command_context, t_con->line)) != ERROR_OK)
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{
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if (retval == ERROR_COMMAND_CLOSE_CONNECTION)
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{
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return ERROR_SERVER_REMOTE_CLOSED;
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}
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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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/* 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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/* wrap history at TELNET_LINE_HISTORY_SIZE */
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if (t_con->next_history > TELNET_LINE_HISTORY_SIZE - 1)
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t_con->next_history = 0;
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if (!t_con->surpress_prompt)
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{
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telnet_prompt(connection);
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}
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else
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{
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t_con->surpress_prompt = 0;
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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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}
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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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write(connection->fd, "\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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write(connection->fd, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor);
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write(connection->fd, " \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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write(connection->fd, "\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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write(connection->fd, "\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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write(connection->fd, "\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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write(connection->fd, 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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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 '\xfe':
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t_con->state = TELNET_STATE_DONT;
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break;
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case '\xfd':
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t_con->state = TELNET_STATE_DO;
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break;
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case '\xfc':
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t_con->state = TELNET_STATE_WONT;
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break;
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case '\xfb':
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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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write(connection->fd, "\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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write(connection->fd, 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 - 1 >= 0) ? t_con->current_history - 1 : 127;
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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 + 1);
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write(connection->fd, 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 < 128) ? t_con->current_history + 1 : 0;
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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 + 1);
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write(connection->fd, 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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write(connection->fd, 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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write(connection->fd, " \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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write(connection->fd, "\b", 1);
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}
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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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t_con->state = TELNET_STATE_DATA;
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}
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}
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else if (t_con->last_escape == '\x00')
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{
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if (*buf_p == '[')
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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
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{
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ERROR("BUG: unexpected value in t_con->last_escape");
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t_con->state = TELNET_STATE_DATA;
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}
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break;
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default:
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ERROR("unknown telnet state");
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exit(-1);
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}
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bytes_read--;
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buf_p++;
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}
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return ERROR_OK;
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}
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int telnet_connection_closed(connection_t *connection)
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{
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telnet_connection_t *t_con = connection->priv;
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int i;
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if (t_con->prompt)
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free(t_con->prompt);
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for (i = 0; i < TELNET_LINE_HISTORY_SIZE; i++)
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{
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if (t_con->history[i])
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free(t_con->history[i]);
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}
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if (connection->priv)
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free(connection->priv);
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else
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ERROR("BUG: connection->priv == NULL");
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target_unregister_event_callback(telnet_target_callback_event_handler, connection->cmd_ctx);
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return ERROR_OK;
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}
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|
|
|
int telnet_set_prompt(connection_t *connection, char *prompt)
|
|
{
|
|
telnet_connection_t *t_con = connection->priv;
|
|
|
|
t_con->prompt = strdup(prompt);
|
|
|
|
return ERROR_OK;
|
|
}
|
|
|
|
int telnet_init(char *banner)
|
|
{
|
|
telnet_service_t *telnet_service = malloc(sizeof(telnet_service_t));
|
|
|
|
if (telnet_port == 0)
|
|
{
|
|
WARNING("no telnet port specified, using default port 4444");
|
|
telnet_port = 4444;
|
|
}
|
|
|
|
telnet_service->banner = banner;
|
|
|
|
add_service("telnet", CONNECTION_TELNET, telnet_port, 1, telnet_new_connection, telnet_input, telnet_connection_closed, telnet_service);
|
|
|
|
return ERROR_OK;
|
|
}
|
|
|
|
int telnet_register_commands(command_context_t *command_context)
|
|
{
|
|
register_command(command_context, NULL, "exit", handle_exit_command,
|
|
COMMAND_EXEC, "exit telnet session");
|
|
|
|
register_command(command_context, NULL, "telnet_port", handle_telnet_port_command,
|
|
COMMAND_CONFIG, "");
|
|
|
|
return ERROR_OK;
|
|
}
|
|
|
|
/* daemon configuration command telnet_port */
|
|
int handle_telnet_port_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc)
|
|
{
|
|
if (argc == 0)
|
|
return ERROR_OK;
|
|
|
|
/* only if the port wasn't overwritten by cmdline */
|
|
if (telnet_port == 0)
|
|
telnet_port = strtoul(args[0], NULL, 0);
|
|
|
|
return ERROR_OK;
|
|
}
|
|
|
|
int handle_exit_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc)
|
|
{
|
|
return ERROR_COMMAND_CLOSE_CONNECTION;
|
|
}
|