diff options
Diffstat (limited to 'src/server/telnet_server.c')
| -rw-r--r-- | src/server/telnet_server.c | 570 |
1 files changed, 570 insertions, 0 deletions
diff --git a/src/server/telnet_server.c b/src/server/telnet_server.c new file mode 100644 index 00000000..d7933293 --- /dev/null +++ b/src/server/telnet_server.c @@ -0,0 +1,570 @@ +/*************************************************************************** + * Copyright (C) 2005 by Dominic Rath * + * Dominic.Rath@gmx.de * + * * + * This program is free software; you can redistribute it and/or modify * + * it under the terms of the GNU General Public License as published by * + * the Free Software Foundation; either version 2 of the License, or * + * (at your option) any later version. * + * * + * This program is distributed in the hope that it will be useful, * + * but WITHOUT ANY WARRANTY; without even the implied warranty of * + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * + * GNU General Public License for more details. * + * * + * You should have received a copy of the GNU General Public License * + * along with this program; if not, write to the * + * Free Software Foundation, Inc., * + * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. * + ***************************************************************************/ +#include "telnet_server.h" + +#include "server.h" +#include "log.h" +#include "command.h" +#include "target.h" + +#include <stdlib.h> +#include <unistd.h> +#include <errno.h> +#include <string.h> +#include <ctype.h> + +static unsigned short telnet_port = 0; + +int handle_exit_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc); +int handle_telnet_port_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc); + +static char *negotiate = + "\xFF\xFB\x03" /* IAC WILL Suppress Go Ahead */ + "\xFF\xFB\x01" /* IAC WILL Echo */ + "\xFF\xFD\x03" /* IAC DO Suppress Go Ahead */ + "\xFF\xFE\x01"; /* IAC DON'T Echo */ + +#define CTRL(c) (c - '@') + +void telnet_prompt(connection_t *connection) +{ + telnet_connection_t *t_con = connection->priv; + + write(connection->fd, t_con->prompt, strlen(t_con->prompt)); +} + +int telnet_output(struct command_context_s *cmd_ctx, char* line) +{ + connection_t *connection = cmd_ctx->output_handler_priv; + + write(connection->fd, line, strlen(line)); + write(connection->fd, "\r\n\0", 3); + + return ERROR_OK; +} + +int telnet_target_callback_event_handler(struct target_s *target, enum target_event event, void *priv) +{ + struct command_context_s *cmd_ctx = priv; + connection_t *connection = cmd_ctx->output_handler_priv; + telnet_connection_t *t_con = connection->priv; + char buffer[512]; + + switch (event) + { + case TARGET_EVENT_HALTED: + command_print(cmd_ctx, "Target %i halted", get_num_by_target(target)); + target->type->arch_state(target, buffer, 512); + buffer[511] = 0; + command_print(cmd_ctx, "%s", buffer); + telnet_prompt(connection); + t_con->surpress_prompt = 1; + break; + case TARGET_EVENT_RESUMED: + command_print(cmd_ctx, "Target %i resumed", get_num_by_target(target)); + telnet_prompt(connection); + t_con->surpress_prompt = 1; + break; + default: + break; + } + + return ERROR_OK; +} + +int telnet_new_connection(connection_t *connection) +{ + telnet_connection_t *telnet_connection = malloc(sizeof(telnet_connection_t)); + telnet_service_t *telnet_service = connection->service->priv; + int i; + + connection->priv = telnet_connection; + + /* initialize telnet connection information */ + telnet_connection->line_size = 0; + telnet_connection->line_cursor = 0; + telnet_connection->option_size = 0; + telnet_connection->prompt = strdup("> "); + telnet_connection->surpress_prompt = 0; + telnet_connection->state = TELNET_STATE_DATA; + + /* output goes through telnet connection */ + command_set_output_handler(connection->cmd_ctx, telnet_output, connection); + + /* negotiate telnet options */ + write(connection->fd, negotiate, strlen(negotiate)); + + /* print connection banner */ + if (telnet_service->banner) + { + write(connection->fd, telnet_service->banner, strlen(telnet_service->banner)); + write(connection->fd, "\r\n\0", 3); + } + + 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; + + target_register_event_callback(telnet_target_callback_event_handler, connection->cmd_ctx); + + return ERROR_OK; +} + +void telnet_clear_line(connection_t *connection, telnet_connection_t *t_con) +{ + /* move to end of line */ + if (t_con->line_cursor < t_con->line_size) + { + write(connection->fd, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor); + } + + /* backspace, overwrite with space, backspace */ + while (t_con->line_size > 0) + { + write(connection->fd, "\b \b", 3); + t_con->line_size--; + } + t_con->line_cursor = 0; +} + +int telnet_input(connection_t *connection) +{ + int bytes_read; + char buffer[TELNET_BUFFER_SIZE]; + char *buf_p; + telnet_connection_t *t_con = connection->priv; + command_context_t *command_context = connection->cmd_ctx; + + bytes_read = read(connection->fd, buffer, TELNET_BUFFER_SIZE); + + if (bytes_read == 0) + return ERROR_SERVER_REMOTE_CLOSED; + else if (bytes_read == -1) + { + 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 == '\xff') + { + t_con->state = TELNET_STATE_IAC; + } + else + { + if (isprint(*buf_p)) /* printable character */ + { + write(connection->fd, buf_p, 1); + if (t_con->line_cursor == t_con->line_size) + { + 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++; + write(connection->fd, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor); + for (i = t_con->line_cursor; i < t_con->line_size; i++) + { + write(connection->fd, "\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 + NUL */ + if (((*(buf_p + 1) == 0xa) || (*(buf_p + 1) == 0xd)) && (bytes_read > 1)) + { + buf_p++; + bytes_read--; + } + if ((*(buf_p + 1) == 0) && (bytes_read > 1)) + { + buf_p++; + bytes_read--; + } + t_con->line[t_con->line_size] = 0; + + write(connection->fd, "\r\n\x00", 3); + + if (strcmp(t_con->line, "history") == 0) + { + int i; + for (i = 0; i < TELNET_LINE_HISTORY_SIZE; i++) + { + if (t_con->history[i]) + { + write(connection->fd, t_con->history[i], strlen(t_con->history[i])); + write(connection->fd, "\r\n\x00", 3); + } + } + telnet_prompt(connection); + t_con->line_size = 0; + t_con->line_cursor = 0; + continue; + } + + /* we're running a command, so we need a prompt + * if the output handler is called, this gets set again */ + t_con->surpress_prompt = 0; + if ((retval = command_run_line(command_context, t_con->line)) != ERROR_OK) + { + if (retval == ERROR_COMMAND_CLOSE_CONNECTION) + { + return ERROR_SERVER_REMOTE_CLOSED; + } + } + + /* 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); + + /* 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(""); + + /* wrap history at TELNET_LINE_HISTORY_SIZE */ + if (t_con->next_history > TELNET_LINE_HISTORY_SIZE - 1) + t_con->next_history = 0; + + if (!t_con->surpress_prompt) + { + telnet_prompt(connection); + } + else + { + t_con->surpress_prompt = 0; + } + + t_con->line_size = 0; + t_con->line_cursor = 0; + } + 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; + write(connection->fd, "\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); + + write(connection->fd, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor); + write(connection->fd, " \b", 2); + for (i = t_con->line_cursor; i < t_con->line_size; i++) + { + write(connection->fd, "\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 */ + write(connection->fd, "\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) + { + write(connection->fd, "\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) + { + write(connection->fd, t_con->line + t_con->line_cursor++, 1); + } + t_con->state = TELNET_STATE_DATA; + } + else + { + DEBUG("unhandled nonprintable: %2.2x", *buf_p); + } + } + } + break; + case TELNET_STATE_IAC: + switch (*buf_p) + { + case '\xfe': + t_con->state = TELNET_STATE_DONT; + break; + case '\xfd': + t_con->state = TELNET_STATE_DO; + break; + case '\xfc': + t_con->state = TELNET_STATE_WONT; + break; + case '\xfb': + 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) + { + write(connection->fd, "\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) + { + write(connection->fd, t_con->line + t_con->line_cursor++, 1); + } + t_con->state = TELNET_STATE_DATA; + } + else if (*buf_p == 'A') /* cursor up */ + { + int last_history = (t_con->current_history - 1 >= 0) ? t_con->current_history - 1 : 127; + if (t_con->history[last_history]) + { + telnet_clear_line(connection, t_con); + t_con->line_size = strlen(t_con->history[last_history]); + t_con->line_cursor = t_con->line_size; + memcpy(t_con->line, t_con->history[last_history], t_con->line_size + 1); + write(connection->fd, t_con->line, t_con->line_size); + t_con->current_history = last_history; + } + t_con->state = TELNET_STATE_DATA; + } + else if (*buf_p == 'B') /* cursor down */ + { + int next_history = (t_con->current_history + 1 < 128) ? t_con->current_history + 1 : 0; + if (t_con->history[next_history]) + { + telnet_clear_line(connection, t_con); + t_con->line_size = strlen(t_con->history[next_history]); + t_con->line_cursor = t_con->line_size; + memcpy(t_con->line, t_con->history[next_history], t_con->line_size + 1); + write(connection->fd, t_con->line, t_con->line_size); + t_con->current_history = next_history; + } + t_con->state = TELNET_STATE_DATA; + } + 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 */ + write(connection->fd, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor); + /* overwrite last char with whitespace */ + write(connection->fd, " \b", 2); + + /* move back to cursor position*/ + for (i = t_con->line_cursor; i < t_con->line_size; i++) + { + write(connection->fd, "\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 + { + ERROR("BUG: unexpected value in t_con->last_escape"); + t_con->state = TELNET_STATE_DATA; + } + + break; + default: + ERROR("unknown telnet state"); + exit(-1); + } + + bytes_read--; + buf_p++; + } + + return ERROR_OK; +} + +int telnet_connection_closed(connection_t *connection) +{ + telnet_connection_t *t_con = connection->priv; + int i; + + if (t_con->prompt) + free(t_con->prompt); + + for (i = 0; i < TELNET_LINE_HISTORY_SIZE; i++) + { + if (t_con->history[i]) + free(t_con->history[i]); + } + + if (connection->priv) + free(connection->priv); + else + ERROR("BUG: connection->priv == NULL"); + + target_unregister_event_callback(telnet_target_callback_event_handler, connection->cmd_ctx); + + return ERROR_OK; +} + +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; +} |