diff options
| -rw-r--r-- | src/server/telnet_server.c | 154 |
1 files changed, 87 insertions, 67 deletions
diff --git a/src/server/telnet_server.c b/src/server/telnet_server.c index 95fe422b..73579e4b 100644 --- a/src/server/telnet_server.c +++ b/src/server/telnet_server.c @@ -47,9 +47,9 @@ static char *negotiate = "\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 - '@') - + /* The only way we can detect that the socket is closed is the first time * we write to it, we will fail. Subsequent write operations will * succeed. Shudder! @@ -72,18 +72,18 @@ int telnet_prompt(connection_t *connection) { telnet_connection_t *t_con = connection->priv; - telnet_write(connection, "\r", 1); /* the prompt is always placed at the line beginning */ + telnet_write(connection, "\r", 1); /* the prompt is always placed at the line beginning */ return telnet_write(connection, t_con->prompt, strlen(t_con->prompt)); } int telnet_outputline(connection_t *connection, const char *line) { int len; - + /* process lines in buffer */ while (*line) { char *line_end = strchr(line, '\n'); - + if (line_end) len = line_end-line; else @@ -100,32 +100,40 @@ int telnet_outputline(connection_t *connection, const char *line) line += len; } } - + return ERROR_OK; } int telnet_output(struct command_context_s *cmd_ctx, char* line) { connection_t *connection = cmd_ctx->output_handler_priv; - + return telnet_outputline(connection, line); } -void telnet_log_callback(void *priv, const char *file, int line, +void telnet_log_callback(void *priv, const char *file, int line, const char *function, const char *string) { connection_t *connection = priv; telnet_connection_t *t_con = connection->priv; int i; - + + /* if there is no prompt, simply output the message */ + if (t_con->line_cursor < 0) + { + telnet_outputline(connection, string); + return; + } + /* clear the command line */ telnet_write(connection, "\r", 1); for (i = strlen(t_con->prompt) + t_con->line_size; i>0; i-=16) telnet_write(connection, " ", i>16 ? 16 : i); - telnet_write(connection, "\r", 1); + + /* output the message */ telnet_outputline(connection, string); - + /* put the command line to its previous state */ telnet_prompt(connection); telnet_write(connection, t_con->line, t_con->line_size); @@ -152,9 +160,9 @@ 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->closed = 0; telnet_connection->line_size = 0; @@ -162,22 +170,22 @@ int telnet_new_connection(connection_t *connection) telnet_connection->option_size = 0; telnet_connection->prompt = strdup("> "); telnet_connection->state = TELNET_STATE_DATA; - + /* output goes through telnet connection */ command_set_output_handler(connection->cmd_ctx, telnet_output, connection); - + /* negotiate telnet options */ telnet_write(connection, negotiate, strlen(negotiate)); - + /* print connection banner */ if (telnet_service->banner) { telnet_write(connection, telnet_service->banner, strlen(telnet_service->banner)); telnet_write(connection, "\r\n\0", 3); } - + telnet_prompt(connection); - + /* initialize history */ for (i = 0; i < TELNET_LINE_HISTORY_SIZE; i++) { @@ -187,11 +195,11 @@ int telnet_new_connection(connection_t *connection) telnet_connection->current_history = 0; target_register_event_callback(telnet_target_callback_event_handler, connection->cmd_ctx); - + log_add_callback(telnet_log_callback, connection); - + return ERROR_OK; } @@ -219,9 +227,9 @@ int telnet_input(connection_t *connection) char *buf_p; telnet_connection_t *t_con = connection->priv; command_context_t *command_context = connection->cmd_ctx; - + bytes_read = read_socket(connection->fd, buffer, TELNET_BUFFER_SIZE); - + if (bytes_read == 0) return ERROR_SERVER_REMOTE_CLOSED; else if (bytes_read == -1) @@ -229,7 +237,7 @@ int telnet_input(connection_t *connection) ERROR("error during read: %s", strerror(errno)); return ERROR_SERVER_REMOTE_CLOSED; } - + buf_p = buffer; while (bytes_read) { @@ -244,9 +252,15 @@ int telnet_input(connection_t *connection) { if (isprint(*buf_p)) /* printable character */ { - telnet_write(connection, buf_p, 1); - if (t_con->line_cursor == t_con->line_size) + /* watch buffer size leaving one spare character for string null termination */ + if (t_con->line_size == TELNET_LINE_MAX_SIZE-1) + { + /* output audible bell if buffer is full */ + telnet_write(connection, "\x07", 1); /* "\a" does not work, at least on windows */ + } + else if (t_con->line_cursor == t_con->line_size) { + telnet_write(connection, buf_p, 1); t_con->line[t_con->line_size++] = *buf_p; t_con->line_cursor++; } @@ -254,9 +268,10 @@ int telnet_input(connection_t *connection) { 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[t_con->line_cursor] = *buf_p; t_con->line_size++; telnet_write(connection, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor); + t_con->line_cursor++; for (i = t_con->line_cursor; i < t_con->line_size; i++) { telnet_write(connection, "\b", 1); @@ -273,30 +288,32 @@ int telnet_input(connection_t *connection) 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)) + + /* skip over combinations with CR/LF and NUL characters */ + if ((bytes_read > 1) && ((*(buf_p + 1) == 0xa) || (*(buf_p + 1) == 0xd))) { buf_p++; bytes_read--; } - if ((*(buf_p + 1) == 0) && (bytes_read > 1)) + if ((bytes_read > 1) && (*(buf_p + 1) == 0)) { buf_p++; bytes_read--; } t_con->line[t_con->line_size] = 0; - + telnet_write(connection, "\r\n\x00", 3); - + if (strcmp(t_con->line, "history") == 0) { int i; - for (i = 0; i < TELNET_LINE_HISTORY_SIZE; i++) + for (i = 1; i < TELNET_LINE_HISTORY_SIZE; i++) { - if (t_con->history[i]) + /* the t_con->next_history line contains empty string (unless NULL), thus it is not printed */ + char *history_line = t_con->history[(t_con->next_history + i) % TELNET_LINE_HISTORY_SIZE]; + if (history_line) { - telnet_write(connection, t_con->history[i], strlen(t_con->history[i])); + telnet_write(connection, history_line, strlen(history_line)); telnet_write(connection, "\r\n\x00", 3); } } @@ -304,43 +321,46 @@ int telnet_input(connection_t *connection) t_con->line_cursor = 0; continue; } - - /* Save only non-blank lines in the history */ - if (t_con->line_size > 0) + + /* save only non-blank not repeating lines in the history */ + char *prev_line = t_con->history[(t_con->current_history > 0) ? t_con->current_history - 1 : TELNET_LINE_HISTORY_SIZE-1]; + if (*t_con->line && (prev_line == NULL || strcmp(t_con->line, prev_line))) { /* if the history slot is already taken, free it */ if (t_con->history[t_con->next_history]) { free(t_con->history[t_con->next_history]); } - + /* add line to history */ t_con->history[t_con->next_history] = strdup(t_con->line); /* wrap history at TELNET_LINE_HISTORY_SIZE */ t_con->next_history = (t_con->next_history + 1) % TELNET_LINE_HISTORY_SIZE; - + /* current history line starts at the new entry */ t_con->current_history = t_con->next_history; - + if (t_con->history[t_con->current_history]) { free(t_con->history[t_con->current_history]); } t_con->history[t_con->current_history] = strdup(""); } - + t_con->line_size = 0; - t_con->line_cursor = 0; + t_con->line_cursor = -1; /* to supress prompt in log callback during command execution */ retval = command_run_line(command_context, t_con->line); + t_con->line_cursor = 0; + if (retval == ERROR_COMMAND_CLOSE_CONNECTION) return ERROR_SERVER_REMOTE_CLOSED; retval = telnet_prompt(connection); if (retval == ERROR_SERVER_REMOTE_CLOSED) return ERROR_SERVER_REMOTE_CLOSED; - + } else if ((*buf_p == 0x7f) || (*buf_p == 0x8)) /* delete character */ { @@ -353,7 +373,7 @@ int telnet_input(connection_t *connection) t_con->line_cursor--; t_con->line_size--; memmove(t_con->line + t_con->line_cursor, t_con->line + t_con->line_cursor + 1, t_con->line_size - t_con->line_cursor); - + telnet_write(connection, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor); telnet_write(connection, " \b", 2); for (i = t_con->line_cursor; i < t_con->line_size; i++) @@ -453,7 +473,7 @@ int telnet_input(connection_t *connection) 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); + memcpy(t_con->line, t_con->history[last_history], t_con->line_size); telnet_write(connection, t_con->line, t_con->line_size); t_con->current_history = last_history; } @@ -467,7 +487,7 @@ int telnet_input(connection_t *connection) 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); + memcpy(t_con->line, t_con->history[next_history], t_con->line_size); telnet_write(connection, t_con->line, t_con->line_size); t_con->current_history = next_history; } @@ -493,19 +513,19 @@ int telnet_input(connection_t *connection) t_con->line_size--; /* remove char from line buffer */ memmove(t_con->line + t_con->line_cursor, t_con->line + t_con->line_cursor + 1, t_con->line_size - t_con->line_cursor); - + /* print remainder of buffer */ telnet_write(connection, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor); /* overwrite last char with whitespace */ telnet_write(connection, " \b", 2); - + /* move back to cursor position*/ for (i = t_con->line_cursor; i < t_con->line_size; i++) { telnet_write(connection, "\b", 1); } } - + t_con->state = TELNET_STATE_DATA; } else @@ -529,7 +549,7 @@ int telnet_input(connection_t *connection) ERROR("BUG: unexpected value in t_con->last_escape"); t_con->state = TELNET_STATE_DATA; } - + break; default: ERROR("unknown telnet state"); @@ -539,7 +559,7 @@ int telnet_input(connection_t *connection) bytes_read--; buf_p++; } - + return ERROR_OK; } @@ -547,15 +567,15 @@ int telnet_connection_closed(connection_t *connection) { telnet_connection_t *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]) @@ -564,10 +584,10 @@ int telnet_connection_closed(connection_t *connection) 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); @@ -577,7 +597,7 @@ int telnet_connection_closed(connection_t *connection) { ERROR("BUG: connection->priv == NULL"); } - + target_unregister_event_callback(telnet_target_callback_event_handler, connection->cmd_ctx); return ERROR_OK; @@ -588,27 +608,27 @@ int telnet_set_prompt(connection_t *connection, char *prompt) telnet_connection_t *t_con = connection->priv; if (t_con->prompt != NULL) - free(t_con->prompt); - + free(t_con->prompt); + 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; } @@ -616,10 +636,10 @@ 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; } |