X-Git-Url: https://review.openocd.org/gitweb?p=openocd.git;a=blobdiff_plain;f=src%2Fserver%2Ftelnet_server.c;h=d0583a9b3e22f36bd2a8007e689491f0c3a2409a;hp=e33188b5e1e0f73c2a9c289e17ce12555050a186;hb=HEAD;hpb=3421b89c9809cbb39cd4bb030687a5c9fd65ded6

diff --git a/src/server/telnet_server.c b/src/server/telnet_server.c
index e33188b5e1..938bc5b062 100644
--- a/src/server/telnet_server.c
+++ b/src/server/telnet_server.c
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
 /***************************************************************************
  *   Copyright (C) 2005 by Dominic Rath                                    *
  *   Dominic.Rath@gmx.de                                                   *
@@ -7,19 +9,6 @@
  *                                                                         *
  *   Copyright (C) 2008 by Spencer Oliver                                  *
  *   spen@spen-soft.co.uk                                                  *
- *                                                                         *
- *   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, see <http://www.gnu.org/licenses/>. *
  ***************************************************************************/
 
 #ifdef HAVE_CONFIG_H
@@ -29,6 +18,7 @@
 #include "telnet_server.h"
 #include <target/target_request.h>
 #include <helper/configuration.h>
+#include <helper/list.h>
 
 static char *telnet_port;
 
@@ -54,10 +44,17 @@ static int telnet_write(struct connection *connection, const void *data,
 
 	if (connection_write(connection, data, len) == len)
 		return ERROR_OK;
-	t_con->closed = 1;
+	t_con->closed = true;
 	return ERROR_SERVER_REMOTE_CLOSED;
 }
 
+/* output an audible bell */
+static int telnet_bell(struct connection *connection)
+{
+	/* ("\a" does not work, at least on windows) */
+	return telnet_write(connection, "\x07", 1);
+}
+
 static int telnet_prompt(struct connection *connection)
 {
 	struct telnet_connection *t_con = connection->priv;
@@ -101,29 +98,36 @@ static void telnet_log_callback(void *priv, const char *file, unsigned line,
 {
 	struct connection *connection = priv;
 	struct telnet_connection *t_con = connection->priv;
-	int i;
+	size_t i;
+	size_t tmp;
 
-	/* if there is no prompt, simply output the message */
-	if (t_con->line_cursor < 0) {
+	/* If the prompt is not visible, simply output the message. */
+	if (!t_con->prompt_visible) {
 		telnet_outputline(connection, string);
 		return;
 	}
 
-	/* clear the command line */
-	for (i = strlen(t_con->prompt) + t_con->line_size; i > 0; i -= 16)
-		telnet_write(connection, "\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b", i > 16 ? 16 : i);
-	for (i = strlen(t_con->prompt) + t_con->line_size; i > 0; i -= 16)
-		telnet_write(connection, "                ", i > 16 ? 16 : i);
-	for (i = strlen(t_con->prompt) + t_con->line_size; i > 0; i -= 16)
-		telnet_write(connection, "\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b", i > 16 ? 16 : i);
+	/* Clear the command line. */
+	tmp = strlen(t_con->prompt) + t_con->line_size;
+
+	for (i = 0; i < tmp; i += 16)
+		telnet_write(connection, "\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b",
+			MIN(tmp - i, 16));
+
+	for (i = 0; i < tmp; i += 16)
+		telnet_write(connection, "                ", MIN(tmp - i, 16));
+
+	for (i = 0; i < tmp; i += 16)
+		telnet_write(connection, "\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b",
+			MIN(tmp - i, 16));
 
-	/* output the message */
 	telnet_outputline(connection, string);
 
-	/* put the command line to its previous state */
+	/* Put the command line to its previous state. */
 	telnet_prompt(connection);
 	telnet_write(connection, t_con->line, t_con->line_size);
-	for (i = t_con->line_size; i > t_con->line_cursor; i--)
+
+	for (i = t_con->line_cursor; i < t_con->line_size; i++)
 		telnet_write(connection, "\b", 1);
 }
 
@@ -135,7 +139,7 @@ static void telnet_load_history(struct telnet_connection *t_con)
 
 	char *history = get_home_dir(TELNET_HISTORY);
 
-	if (history == NULL) {
+	if (!history) {
 		LOG_INFO("unable to get user home directory, telnet history will be disabled");
 		return;
 	}
@@ -144,7 +148,7 @@ static void telnet_load_history(struct telnet_connection *t_con)
 
 	if (histfp) {
 
-		while (fgets(buffer, sizeof(buffer), histfp) != NULL) {
+		while (fgets(buffer, sizeof(buffer), histfp)) {
 
 			char *p = strchr(buffer, '\n');
 			if (p)
@@ -171,7 +175,7 @@ static void telnet_save_history(struct telnet_connection *t_con)
 
 	char *history = get_home_dir(TELNET_HISTORY);
 
-	if (history == NULL) {
+	if (!history) {
 		LOG_INFO("unable to get user home directory, telnet history will be disabled");
 		return;
 	}
@@ -184,7 +188,7 @@ static void telnet_save_history(struct telnet_connection *t_con)
 		i = t_con->current_history + 1;
 		i %= TELNET_LINE_HISTORY_SIZE;
 
-		while (t_con->history[i] == NULL && num > 0) {
+		while (!t_con->history[i] && num > 0) {
 			i++;
 			i %= TELNET_LINE_HISTORY_SIZE;
 			num--;
@@ -207,9 +211,8 @@ static int telnet_new_connection(struct connection *connection)
 {
 	struct telnet_connection *telnet_connection;
 	struct telnet_service *telnet_service = connection->service->priv;
-	int i;
 
-	telnet_connection = malloc(sizeof(struct telnet_connection));
+	telnet_connection = calloc(1, sizeof(struct telnet_connection));
 
 	if (!telnet_connection) {
 		LOG_ERROR("Failed to allocate telnet connection.");
@@ -219,11 +222,8 @@ static int telnet_new_connection(struct connection *connection)
 	connection->priv = telnet_connection;
 
 	/* initialize telnet connection information */
-	telnet_connection->closed = 0;
-	telnet_connection->line_size = 0;
-	telnet_connection->line_cursor = 0;
-	telnet_connection->option_size = 0;
 	telnet_connection->prompt = strdup("> ");
+	telnet_connection->prompt_visible = true;
 	telnet_connection->state = TELNET_STATE_DATA;
 
 	/* output goes through telnet connection */
@@ -242,11 +242,6 @@ static int telnet_new_connection(struct connection *connection)
 	telnet_write(connection, "\r", 1);
 	telnet_prompt(connection);
 
-	/* initialize history */
-	for (i = 0; i < TELNET_LINE_HISTORY_SIZE; i++)
-		telnet_connection->history[i] = NULL;
-	telnet_connection->next_history = 0;
-	telnet_connection->current_history = 0;
 	telnet_load_history(telnet_connection);
 
 	log_add_callback(telnet_log_callback, connection);
@@ -290,7 +285,7 @@ static void telnet_history_up(struct connection *connection)
 {
 	struct telnet_connection *t_con = connection->priv;
 
-	int last_history = (t_con->current_history > 0) ?
+	size_t last_history = (t_con->current_history > 0) ?
 				t_con->current_history - 1 :
 				TELNET_LINE_HISTORY_SIZE-1;
 	telnet_history_go(connection, last_history);
@@ -299,18 +294,465 @@ static void telnet_history_up(struct connection *connection)
 static void telnet_history_down(struct connection *connection)
 {
 	struct telnet_connection *t_con = connection->priv;
+	size_t next_history;
 
-	int next_history = (t_con->current_history + 1) % TELNET_LINE_HISTORY_SIZE;
+	next_history = (t_con->current_history + 1) % TELNET_LINE_HISTORY_SIZE;
 	telnet_history_go(connection, next_history);
 }
 
+static void telnet_history_add(struct connection *connection)
+{
+	struct telnet_connection *t_con = connection->priv;
+
+	/* 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 || strcmp(t_con->line, prev_line))) {
+		/* if the history slot is already taken, free it */
+		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;
+
+		free(t_con->history[t_con->current_history]);
+		t_con->history[t_con->current_history] = strdup("");
+	}
+}
+
+static int telnet_history_print(struct connection *connection)
+{
+	struct telnet_connection *tc;
+
+	tc = connection->priv;
+
+	for (size_t i = 1; i < TELNET_LINE_HISTORY_SIZE; i++) {
+		char *line;
+
+		/*
+		 * The tc->next_history line contains empty string (unless NULL), thus
+		 * it is not printed.
+		 */
+		line = tc->history[(tc->next_history + i) % TELNET_LINE_HISTORY_SIZE];
+
+		if (line) {
+			telnet_write(connection, line, strlen(line));
+			telnet_write(connection, "\r\n\x00", 3);
+		}
+	}
+
+	tc->line_size = 0;
+	tc->line_cursor = 0;
+
+	/* The prompt is always placed at the line beginning. */
+	telnet_write(connection, "\r", 1);
+
+	return telnet_prompt(connection);
+}
+
+static void telnet_move_cursor(struct connection *connection, size_t pos)
+{
+	struct telnet_connection *tc = connection->priv;
+	size_t tmp;
+
+	if (pos == tc->line_cursor) /* nothing to do */
+		return;
+
+	if (pos > tc->line_size) /* out of bounds */
+		return;
+
+	if (pos < tc->line_cursor) {
+		tmp = tc->line_cursor - pos;
+
+		for (size_t i = 0; i < tmp; i += 16)
+			telnet_write(connection, "\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b",
+				MIN(tmp - i, 16));
+	} else {
+		tmp = pos - tc->line_cursor;
+
+		for (size_t i = 0; i < tmp; i += 16)
+			telnet_write(connection, tc->line + tc->line_cursor + i,
+				MIN(tmp - i, 16));
+	}
+
+	tc->line_cursor = pos;
+}
+
+/* check buffer size leaving one spare character for string null termination */
+static inline bool telnet_can_insert(struct connection *connection, size_t len)
+{
+	struct telnet_connection *t_con = connection->priv;
+
+	return t_con->line_size + len < TELNET_LINE_MAX_SIZE;
+}
+
+/* write to telnet console, and update the telnet_connection members
+ * this function is capable of inserting in the middle of a line
+ * please ensure that data does not contain special characters (\n, \r, \t, \b ...)
+ *
+ * returns false when it fails to insert the requested data
+ */
+static bool telnet_insert(struct connection *connection, const void *data, size_t len)
+{
+	struct telnet_connection *t_con = connection->priv;
+
+	if (!telnet_can_insert(connection, len)) {
+		telnet_bell(connection);
+		return false;
+	}
+
+	if (t_con->line_cursor < t_con->line_size) {
+		/* we have some content after the cursor */
+		memmove(t_con->line + t_con->line_cursor + len,
+				t_con->line + t_con->line_cursor,
+				t_con->line_size - t_con->line_cursor);
+	}
+
+	strncpy(t_con->line + t_con->line_cursor, data, len);
+
+	telnet_write(connection,
+			t_con->line + t_con->line_cursor,
+			t_con->line_size + len - t_con->line_cursor);
+
+	t_con->line_size += len;
+	t_con->line_cursor += len;
+
+	for (size_t i = t_con->line_cursor; i < t_con->line_size; i++)
+		telnet_write(connection, "\b", 1);
+
+	return true;
+}
+
+static void telnet_delete_character(struct connection *connection)
+{
+	struct telnet_connection *t_con = connection->priv;
+
+	if (t_con->line_cursor == 0)
+		return;
+
+	if (t_con->line_cursor != t_con->line_size) {
+		size_t i;
+		telnet_write(connection, "\b", 1);
+		t_con->line_cursor--;
+		t_con->line_size--;
+		memmove(t_con->line + t_con->line_cursor,
+				t_con->line + t_con->line_cursor + 1,
+				t_con->line_size -
+				t_con->line_cursor);
+
+		telnet_write(connection,
+				t_con->line + t_con->line_cursor,
+				t_con->line_size -
+				t_con->line_cursor);
+		telnet_write(connection, " \b", 2);
+		for (i = t_con->line_cursor; i < t_con->line_size; i++)
+			telnet_write(connection, "\b", 1);
+	} else {
+		t_con->line_size--;
+		t_con->line_cursor--;
+		/* back space: move the 'printer' head one char
+		 * back, overwrite with space, move back again */
+		telnet_write(connection, "\b \b", 3);
+	}
+}
+
+static void telnet_remove_character(struct connection *connection)
+{
+	struct telnet_connection *t_con = connection->priv;
+
+	if (t_con->line_cursor < t_con->line_size) {
+		size_t i;
+		t_con->line_size--;
+		/* remove char from line buffer */
+		memmove(t_con->line + t_con->line_cursor,
+				t_con->line + t_con->line_cursor + 1,
+				t_con->line_size - t_con->line_cursor);
+
+		/* print remainder of buffer */
+		telnet_write(connection, t_con->line + t_con->line_cursor,
+				t_con->line_size - t_con->line_cursor);
+		/* overwrite last char with whitespace */
+		telnet_write(connection, " \b", 2);
+
+		/* move back to cursor position*/
+		for (i = t_con->line_cursor; i < t_con->line_size; i++)
+			telnet_write(connection, "\b", 1);
+	}
+}
+
+static int telnet_exec_line(struct connection *connection)
+{
+	struct telnet_connection *t_con = connection->priv;
+	struct command_context *command_context = connection->cmd_ctx;
+	int retval;
+
+	telnet_write(connection, "\r\n\x00", 3);
+
+	if (strcmp(t_con->line, "history") == 0) {
+		retval = telnet_history_print(connection);
+
+		if (retval != ERROR_OK)
+			return retval;
+
+		return ERROR_OK;
+	}
+
+	telnet_history_add(connection);
+
+	t_con->line_size = 0;
+
+	/* to suppress prompt in log callback during command execution */
+	t_con->prompt_visible = false;
+
+	if (strcmp(t_con->line, "shutdown") == 0)
+		telnet_save_history(t_con);
+
+	retval = command_run_line(command_context, t_con->line);
+
+	t_con->line_cursor = 0;
+	t_con->prompt_visible = true;
+
+	if (retval == ERROR_COMMAND_CLOSE_CONNECTION)
+		return ERROR_SERVER_REMOTE_CLOSED;
+
+	/* the prompt is always placed at the line beginning */
+	telnet_write(connection, "\r", 1);
+
+	retval = telnet_prompt(connection);
+	if (retval == ERROR_SERVER_REMOTE_CLOSED)
+		return ERROR_SERVER_REMOTE_CLOSED;
+
+	return ERROR_OK;
+}
+
+static void telnet_cut_line_to_end(struct connection *connection)
+{
+	struct telnet_connection *t_con = connection->priv;
+
+	/* FIXME: currently this function does not save to clipboard */
+
+	if (t_con->line_cursor < t_con->line_size) {
+		/* overwrite with space, until end of line, move back */
+		for (size_t i = t_con->line_cursor; i < t_con->line_size; i++)
+			telnet_write(connection, " ", 1);
+		for (size_t i = t_con->line_cursor; i < t_con->line_size; i++)
+			telnet_write(connection, "\b", 1);
+		t_con->line[t_con->line_cursor] = '\0';
+		t_con->line_size = t_con->line_cursor;
+	}
+}
+
+static void telnet_interrupt(struct connection *connection)
+{
+	struct telnet_connection *t_con = connection->priv;
+
+	/* print '^C' at line end, and display a new command prompt */
+	telnet_move_cursor(connection, t_con->line_size);
+	telnet_write(connection, "^C\n\r", 4);
+	t_con->line_cursor = 0;
+	t_con->line_size = 0;
+	telnet_prompt(connection);
+}
+
+static void telnet_auto_complete(struct connection *connection)
+{
+	struct telnet_connection *t_con = connection->priv;
+	struct command_context *command_context = connection->cmd_ctx;
+
+	struct cmd_match {
+		char *cmd;
+		struct list_head lh;
+	};
+
+	LIST_HEAD(matches);
+
+	/* - user command sequence, either at line beginning
+	 *   or we start over after these characters ';', '[', '{'
+	 * - user variable sequence, start after the character '$'
+	 *   and do not contain white spaces */
+	bool is_variable_auto_completion = false;
+	bool have_spaces = false;
+	size_t seq_start = (t_con->line_cursor == 0) ? 0 : (t_con->line_cursor - 1);
+	while (1) {
+		char c = t_con->line[seq_start];
+
+		if (c == ';' || c == '[' || c == '{') {
+			seq_start++;
+			break;
+		} else if (c == ' ') {
+			have_spaces = true;
+		} else if (c == '$' && !have_spaces) {
+			is_variable_auto_completion = true;
+			seq_start++;
+			break;
+		}
+
+		if (seq_start == 0)
+			break;
+
+		seq_start--;
+	}
+
+	/* user command position in the line, ignore leading spaces */
+	size_t usr_cmd_pos = seq_start;
+	while ((usr_cmd_pos < t_con->line_cursor) && isspace(t_con->line[usr_cmd_pos]))
+		usr_cmd_pos++;
+
+	/* check user command length */
+	if (t_con->line_cursor < usr_cmd_pos) {
+		telnet_bell(connection);
+		return;
+	}
+	size_t usr_cmd_len = t_con->line_cursor - usr_cmd_pos;
+
+	/* optimize multiple spaces in the user command,
+	 * because info commands does not tolerate multiple spaces */
+	size_t optimized_spaces = 0;
+	char query[usr_cmd_len + 1];
+	for (size_t i = 0; i < usr_cmd_len; i++) {
+		if ((i < usr_cmd_len - 1) && isspace(t_con->line[usr_cmd_pos + i])
+				&& isspace(t_con->line[usr_cmd_pos + i + 1])) {
+			optimized_spaces++;
+			continue;
+		}
+
+		query[i - optimized_spaces] = t_con->line[usr_cmd_pos + i];
+	}
+
+	usr_cmd_len -= optimized_spaces;
+	query[usr_cmd_len] = '\0';
+
+	/* filter commands */
+	char *query_cmd;
+
+	if (is_variable_auto_completion)
+		query_cmd = alloc_printf("lsort [info vars {%s*}]", query);
+	else
+		query_cmd = alloc_printf("_telnet_autocomplete_helper {%s*}", query);
+
+	if (!query_cmd) {
+		LOG_ERROR("Out of memory");
+		return;
+	}
+
+	int retval = Jim_EvalSource(command_context->interp, __FILE__, __LINE__, query_cmd);
+	free(query_cmd);
+	if (retval != JIM_OK)
+		return;
+
+	Jim_Obj *list = Jim_GetResult(command_context->interp);
+	Jim_IncrRefCount(list);
+
+	/* common prefix length of the matched commands */
+	size_t common_len = 0;
+	char *first_match = NULL; /* used to compute the common prefix length */
+
+	int len = Jim_ListLength(command_context->interp, list);
+	for (int i = 0; i < len; i++) {
+		Jim_Obj *elem = Jim_ListGetIndex(command_context->interp, list, i);
+		Jim_IncrRefCount(elem);
+
+		char *name = (char *)Jim_GetString(elem, NULL);
+
+		/* validate the command */
+		bool ignore_cmd = false;
+		if (!is_variable_auto_completion) {
+			Jim_Cmd *jim_cmd = Jim_GetCommand(command_context->interp, elem, JIM_NONE);
+
+			if (!jim_cmd) {
+				/* Why we are here? Let's ignore it! */
+				ignore_cmd = true;
+			} else if (jimcmd_is_oocd_command(jim_cmd)) {
+				struct command *cmd = jimcmd_privdata(jim_cmd);
+
+				if (cmd && !cmd->handler && !cmd->jim_handler) {
+					/* Initial part of a multi-word command. Ignore it! */
+					ignore_cmd = true;
+				} else if (cmd && cmd->mode == COMMAND_CONFIG) {
+					/* Not executable after config phase. Ignore it! */
+					ignore_cmd = true;
+				}
+			}
+		}
+
+		/* save the command in the prediction list */
+		if (!ignore_cmd) {
+			struct cmd_match *match = calloc(1, sizeof(struct cmd_match));
+			if (!match) {
+				LOG_ERROR("Out of memory");
+				Jim_DecrRefCount(command_context->interp, elem);
+				break; /* break the for loop */
+			}
+
+			if (list_empty(&matches)) {
+				common_len = strlen(name);
+				first_match = name;
+			} else {
+				size_t new_common_len = usr_cmd_len; /* save some loops */
+
+				while (new_common_len < common_len && first_match[new_common_len] == name[new_common_len])
+					new_common_len++;
+
+				common_len = new_common_len;
+			}
+
+			match->cmd = name;
+			list_add_tail(&match->lh, &matches);
+		}
+
+		Jim_DecrRefCount(command_context->interp, elem);
+	}
+	/* end of command filtering */
+
+	/* proceed with auto-completion */
+	if (list_empty(&matches))
+		telnet_bell(connection);
+	else if (common_len == usr_cmd_len && list_is_singular(&matches) && t_con->line_cursor == t_con->line_size)
+		telnet_insert(connection, " ", 1);
+	else if (common_len > usr_cmd_len) {
+		int completion_size = common_len - usr_cmd_len;
+		if (telnet_insert(connection, first_match + usr_cmd_len, completion_size)) {
+			/* in bash this extra space is only added when the cursor in at the end of line */
+			if (list_is_singular(&matches) && t_con->line_cursor == t_con->line_size)
+				telnet_insert(connection, " ", 1);
+		}
+	} else if (!list_is_singular(&matches)) {
+		telnet_write(connection, "\n\r", 2);
+
+		struct cmd_match *match;
+		list_for_each_entry(match, &matches, lh) {
+			telnet_write(connection, match->cmd, strlen(match->cmd));
+			telnet_write(connection, "\n\r", 2);
+		}
+
+		telnet_prompt(connection);
+		telnet_write(connection, t_con->line, t_con->line_size);
+
+		/* restore the terminal visible cursor location */
+		for (size_t i = t_con->line_cursor; i < t_con->line_size; i++)
+			telnet_write(connection, "\b", 1);
+	}
+
+	/* destroy the command_list */
+	struct cmd_match *tmp, *match;
+	list_for_each_entry_safe(match, tmp, &matches, lh)
+		free(match);
+
+	Jim_DecrRefCount(command_context->interp, list);
+}
+
 static int telnet_input(struct connection *connection)
 {
 	int bytes_read;
 	unsigned char buffer[TELNET_BUFFER_SIZE];
 	unsigned char *buf_p;
 	struct telnet_connection *t_con = connection->priv;
-	struct command_context *command_context = connection->cmd_ctx;
 
 	bytes_read = connection_read(connection, buffer, TELNET_BUFFER_SIZE);
 
@@ -325,39 +767,16 @@ static int telnet_input(struct connection *connection)
 	while (bytes_read) {
 		switch (t_con->state) {
 			case TELNET_STATE_DATA:
-				if (*buf_p == 0xff)
+				if (*buf_p == 0xff) {
 					t_con->state = TELNET_STATE_IAC;
-				else {
+				} else {
 					if (isprint(*buf_p)) {	/* printable character */
-						/* watch buffer size leaving one spare character for
-						 * string null termination */
-						if (t_con->line_size == TELNET_LINE_MAX_SIZE-1) {
-							/* output audible bell if buffer is full
-							 * "\a" does not work, at least on windows */
-							telnet_write(connection, "\x07", 1);
-						} else if (t_con->line_cursor == t_con->line_size) {
-							telnet_write(connection, buf_p, 1);
-							t_con->line[t_con->line_size++] = *buf_p;
-							t_con->line_cursor++;
-						} else {
-							int i;
-							memmove(t_con->line + t_con->line_cursor + 1,
-									t_con->line + t_con->line_cursor,
-									t_con->line_size - t_con->line_cursor);
-							t_con->line[t_con->line_cursor] = *buf_p;
-							t_con->line_size++;
-							telnet_write(connection,
-									t_con->line + t_con->line_cursor,
-									t_con->line_size - t_con->line_cursor);
-							t_con->line_cursor++;
-							for (i = t_con->line_cursor; i < t_con->line_size; i++)
-								telnet_write(connection, "\b", 1);
-						}
-					} else {	/* non-printable */
+						telnet_insert(connection, buf_p, 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 */
+						} else if ((*buf_p == 0xd) || (*buf_p == 0xa)) { /* CR/LF */
 							int retval;
 
 							/* skip over combinations with CR/LF and NUL characters */
@@ -372,119 +791,36 @@ static int telnet_input(struct connection *connection)
 							}
 							t_con->line[t_con->line_size] = 0;
 
-							telnet_write(connection, "\r\n\x00", 3);
-
-							if (strcmp(t_con->line, "history") == 0) {
-								int i;
-								for (i = 1; i < TELNET_LINE_HISTORY_SIZE; i++) {
-									/* the t_con->next_history line contains empty string
-									 * (unless NULL), thus it is not printed */
-									char *history_line = t_con->history[(t_con->
-											next_history + i) %
-											TELNET_LINE_HISTORY_SIZE];
-									if (history_line) {
-										telnet_write(connection, history_line,
-												strlen(history_line));
-										telnet_write(connection, "\r\n\x00", 3);
-									}
-								}
-								t_con->line_size = 0;
-								t_con->line_cursor = 0;
-								continue;
-							}
-
-							/* save only non-blank not repeating lines in the history */
-							char *prev_line = t_con->history[(t_con->current_history > 0) ?
-									t_con->current_history - 1 : TELNET_LINE_HISTORY_SIZE-1];
-							if (*t_con->line && (prev_line == NULL ||
-									strcmp(t_con->line, prev_line))) {
-								/* if the history slot is already taken, free it */
-								if (t_con->history[t_con->next_history])
-									free(t_con->history[t_con->next_history]);
-
-								/* add line to history */
-								t_con->history[t_con->next_history] = strdup(t_con->line);
-
-								/* wrap history at TELNET_LINE_HISTORY_SIZE */
-								t_con->next_history = (t_con->next_history + 1) %
-										TELNET_LINE_HISTORY_SIZE;
-
-								/* current history line starts at the new entry */
-								t_con->current_history =
-										t_con->next_history;
-
-								if (t_con->history[t_con->current_history])
-									free(t_con->history[t_con->current_history]);
-								t_con->history[t_con->current_history] = strdup("");
-							}
-
-							t_con->line_size = 0;
-
-							/* to suppress prompt in log callback during command execution */
-							t_con->line_cursor = -1;
-
-							if (strcmp(t_con->line, "shutdown") == 0)
-								telnet_save_history(t_con);
-
-							retval = command_run_line(command_context, t_con->line);
-
-							t_con->line_cursor = 0;
-
-							if (retval == ERROR_COMMAND_CLOSE_CONNECTION)
-								return ERROR_SERVER_REMOTE_CLOSED;
-
-							/* the prompt is always * placed at the line beginning */
-							telnet_write(connection, "\r", 1);
-
-							retval = telnet_prompt(connection);
-							if (retval == ERROR_SERVER_REMOTE_CLOSED)
-								return ERROR_SERVER_REMOTE_CLOSED;
-
+							retval = telnet_exec_line(connection);
+							if (retval != ERROR_OK)
+								return retval;
 						} else if ((*buf_p == 0x7f) || (*buf_p == 0x8)) {	/* delete character */
-							if (t_con->line_cursor > 0) {
-								if (t_con->line_cursor != t_con->line_size) {
-									int i;
-									telnet_write(connection, "\b", 1);
-									t_con->line_cursor--;
-									t_con->line_size--;
-									memmove(t_con->line + t_con->line_cursor,
-											t_con->line + t_con->line_cursor + 1,
-											t_con->line_size -
-											t_con->line_cursor);
-
-									telnet_write(connection,
-											t_con->line + t_con->line_cursor,
-											t_con->line_size -
-											t_con->line_cursor);
-									telnet_write(connection, " \b", 2);
-									for (i = t_con->line_cursor; i < t_con->line_size; i++)
-										telnet_write(connection, "\b", 1);
-								} else {
-									t_con->line_size--;
-									t_con->line_cursor--;
-									/* back space: move the 'printer' head one char
-									 * back, overwrite with space, move back again */
-									telnet_write(connection, "\b \b", 3);
-								}
-							}
-						} else if (*buf_p == 0x15) /* clear line */
+							telnet_delete_character(connection);
+						} else if (*buf_p == 0x15) {	/* clear line */
 							telnet_clear_line(connection, t_con);
-						else if (*buf_p == CTRL('B')) {	/* cursor left */
-							if (t_con->line_cursor > 0) {
-								telnet_write(connection, "\b", 1);
-								t_con->line_cursor--;
-							}
+						} else if (*buf_p == CTRL('B')) {	/* cursor left */
+							telnet_move_cursor(connection, t_con->line_cursor - 1);
 							t_con->state = TELNET_STATE_DATA;
+						} else if (*buf_p == CTRL('C')) {	/* interrupt */
+							telnet_interrupt(connection);
 						} else if (*buf_p == CTRL('F')) {	/* cursor right */
-							if (t_con->line_cursor < t_con->line_size)
-								telnet_write(connection, t_con->line + t_con->line_cursor++, 1);
+							telnet_move_cursor(connection, t_con->line_cursor + 1);
 							t_con->state = TELNET_STATE_DATA;
-						} else if (*buf_p == CTRL('P'))		/* cursor up */
+						} else if (*buf_p == CTRL('P')) {	/* cursor up */
 							telnet_history_up(connection);
-						else if (*buf_p == CTRL('N'))		/* cursor down */
+						} else if (*buf_p == CTRL('N')) {	/* cursor down */
 							telnet_history_down(connection);
-						else
+						} else if (*buf_p == CTRL('A')) {	/* move the cursor to the beginning of the line */
+							telnet_move_cursor(connection, 0);
+						} else if (*buf_p == CTRL('E')) {	/* move the cursor to the end of the line */
+							telnet_move_cursor(connection, t_con->line_size);
+						} else if (*buf_p == CTRL('K')) {	/* kill line to end */
+							telnet_cut_line_to_end(connection);
+						} else if (*buf_p == '\t') {
+							telnet_auto_complete(connection);
+						} else {
 							LOG_DEBUG("unhandled nonprintable: %2.2x", *buf_p);
+						}
 					}
 				}
 				break;
@@ -517,46 +853,30 @@ static int telnet_input(struct connection *connection)
 			case TELNET_STATE_ESCAPE:
 				if (t_con->last_escape == '[') {
 					if (*buf_p == 'D') {	/* cursor left */
-						if (t_con->line_cursor > 0) {
-							telnet_write(connection, "\b", 1);
-							t_con->line_cursor--;
-						}
+						telnet_move_cursor(connection, t_con->line_cursor - 1);
 						t_con->state = TELNET_STATE_DATA;
 					} else if (*buf_p == 'C') {	/* cursor right */
-						if (t_con->line_cursor < t_con->line_size)
-							telnet_write(connection,
-									t_con->line + t_con->line_cursor++, 1);
+						telnet_move_cursor(connection, t_con->line_cursor + 1);
 						t_con->state = TELNET_STATE_DATA;
 					} else if (*buf_p == 'A') {	/* cursor up */
 						telnet_history_up(connection);
 					} else if (*buf_p == 'B') {	/* cursor down */
 						telnet_history_down(connection);
-					} else if (*buf_p == '3')
+					} else if (*buf_p == 'F') { /* end key */
+						telnet_move_cursor(connection, t_con->line_size);
+						t_con->state = TELNET_STATE_DATA;
+					} else if (*buf_p == 'H') { /* home key */
+						telnet_move_cursor(connection, 0);
+						t_con->state = TELNET_STATE_DATA;
+					} else if (*buf_p == '3') {
 						t_con->last_escape = *buf_p;
-					else
+					} else {
 						t_con->state = TELNET_STATE_DATA;
+					}
 				} else if (t_con->last_escape == '3') {
 					/* Remove character */
 					if (*buf_p == '~') {
-						if (t_con->line_cursor < t_con->line_size) {
-							int i;
-							t_con->line_size--;
-							/* remove char from line buffer */
-							memmove(t_con->line + t_con->line_cursor,
-									t_con->line + t_con->line_cursor + 1,
-									t_con->line_size - t_con->line_cursor);
-
-							/* print remainder of buffer */
-							telnet_write(connection, t_con->line + t_con->line_cursor,
-									t_con->line_size - t_con->line_cursor);
-							/* overwrite last char with whitespace */
-							telnet_write(connection, " \b", 2);
-
-							/* move back to cursor position*/
-							for (i = t_con->line_cursor; i < t_con->line_size; i++)
-								telnet_write(connection, "\b", 1);
-						}
-
+						telnet_remove_character(connection);
 						t_con->state = TELNET_STATE_DATA;
 					} else
 						t_con->state = TELNET_STATE_DATA;
@@ -590,33 +910,35 @@ static int telnet_connection_closed(struct connection *connection)
 
 	log_remove_callback(telnet_log_callback, connection);
 
-	if (t_con->prompt) {
-		free(t_con->prompt);
-		t_con->prompt = NULL;
-	}
+	free(t_con->prompt);
+	t_con->prompt = NULL;
 
 	/* save telnet history */
 	telnet_save_history(t_con);
 
 	for (i = 0; i < TELNET_LINE_HISTORY_SIZE; i++) {
-		if (t_con->history[i]) {
-			free(t_con->history[i]);
-			t_con->history[i] = NULL;
-		}
+		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");
+	free(connection->priv);
+	connection->priv = NULL;
 
 	return ERROR_OK;
 }
 
+static const struct service_driver telnet_service_driver = {
+	.name = "telnet",
+	.new_connection_during_keep_alive_handler = NULL,
+	.new_connection_handler = telnet_new_connection,
+	.input_handler = telnet_input,
+	.connection_closed_handler = telnet_connection_closed,
+	.keep_client_alive_handler = NULL,
+};
+
 int telnet_init(char *banner)
 {
 	if (strcmp(telnet_port, "disabled") == 0) {
@@ -634,8 +956,7 @@ int telnet_init(char *banner)
 
 	telnet_service->banner = banner;
 
-	int ret = add_service("telnet", telnet_port, CONNECTION_LIMIT_UNLIMITED,
-		telnet_new_connection, telnet_input, telnet_connection_closed,
+	int ret = add_service(&telnet_service_driver, telnet_port, CONNECTION_LIMIT_UNLIMITED,
 		telnet_service);
 
 	if (ret != ERROR_OK) {
@@ -668,7 +989,7 @@ static const struct command_registration telnet_command_handlers[] = {
 	{
 		.name = "telnet_port",
 		.handler = handle_telnet_port_command,
-		.mode = COMMAND_ANY,
+		.mode = COMMAND_CONFIG,
 		.help = "Specify port on which to listen "
 			"for incoming telnet connections.  "
 			"Read help on 'gdb_port'.",
@@ -682,3 +1003,8 @@ int telnet_register_commands(struct command_context *cmd_ctx)
 	telnet_port = strdup("4444");
 	return register_commands(cmd_ctx, NULL, telnet_command_handlers);
 }
+
+void telnet_service_free(void)
+{
+	free(telnet_port);
+}