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openocd/src/server/telnet_server.c

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/* SPDX-License-Identifier: GPL-2.0-or-later */
/***************************************************************************
* Copyright (C) 2005 by Dominic Rath *
* Dominic.Rath@gmx.de *
* *
* Copyright (C) 2007-2010 Øyvind Harboe *
* oyvind.harboe@zylin.com *
* *
* Copyright (C) 2008 by Spencer Oliver *
* spen@spen-soft.co.uk *
***************************************************************************/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "telnet_server.h"
#include <target/target_request.h>
#include <helper/configuration.h>
#include <helper/list.h>
static char *telnet_port;
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 - '@')
#define TELNET_HISTORY ".openocd_history"
/* 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!
*/
static int telnet_write(struct connection *connection, const void *data,
int len)
{
struct telnet_connection *t_con = connection->priv;
if (t_con->closed)
return ERROR_SERVER_REMOTE_CLOSED;
if (connection_write(connection, data, len) == len)
return ERROR_OK;
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;
return telnet_write(connection, t_con->prompt, strlen(t_con->prompt));
}
static int telnet_outputline(struct connection *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
len = strlen(line);
telnet_write(connection, line, len);
if (line_end) {
telnet_write(connection, "\r\n", 2);
line += len + 1;
} else
line += len;
}
return ERROR_OK;
}
static int telnet_output(struct command_context *cmd_ctx, const char *line)
{
struct connection *connection = cmd_ctx->output_handler_priv;
return telnet_outputline(connection, line);
}
static void telnet_log_callback(void *priv, const char *file, unsigned line,
const char *function, const char *string)
{
struct connection *connection = priv;
struct telnet_connection *t_con = connection->priv;
size_t i;
size_t tmp;
/* If the prompt is not visible, simply output the message. */
if (!t_con->prompt_visible) {
telnet_outputline(connection, string);
return;
}
/* 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));
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);
for (i = t_con->line_cursor; i < t_con->line_size; i++)
telnet_write(connection, "\b", 1);
}
static void telnet_load_history(struct telnet_connection *t_con)
{
FILE *histfp;
char buffer[TELNET_BUFFER_SIZE];
int i = 0;
char *history = get_home_dir(TELNET_HISTORY);
if (!history) {
LOG_INFO("unable to get user home directory, telnet history will be disabled");
return;
}
histfp = fopen(history, "rb");
if (histfp) {
while (fgets(buffer, sizeof(buffer), histfp)) {
char *p = strchr(buffer, '\n');
if (p)
*p = '\0';
if (buffer[0] && i < TELNET_LINE_HISTORY_SIZE)
t_con->history[i++] = strdup(buffer);
}
t_con->next_history = i;
t_con->next_history %= TELNET_LINE_HISTORY_SIZE;
/* try to set to last entry - 1, that way we skip over any exit/shutdown cmds */
t_con->current_history = t_con->next_history > 0 ? i - 1 : 0;
fclose(histfp);
}
free(history);
}
static void telnet_save_history(struct telnet_connection *t_con)
{
FILE *histfp;
int i;
int num;
char *history = get_home_dir(TELNET_HISTORY);
if (!history) {
LOG_INFO("unable to get user home directory, telnet history will be disabled");
return;
}
histfp = fopen(history, "wb");
if (histfp) {
num = TELNET_LINE_HISTORY_SIZE;
i = t_con->current_history + 1;
i %= TELNET_LINE_HISTORY_SIZE;
while (!t_con->history[i] && num > 0) {
i++;
i %= TELNET_LINE_HISTORY_SIZE;
num--;
}
if (num > 0) {
for (; num > 0; num--) {
fprintf(histfp, "%s\n", t_con->history[i]);
i++;
i %= TELNET_LINE_HISTORY_SIZE;
}
}
fclose(histfp);
}
free(history);
}
static int telnet_new_connection(struct connection *connection)
{
struct telnet_connection *telnet_connection;
struct telnet_service *telnet_service = connection->service->priv;
telnet_connection = calloc(1, sizeof(struct telnet_connection));
if (!telnet_connection) {
LOG_ERROR("Failed to allocate telnet connection.");
return ERROR_FAIL;
}
connection->priv = telnet_connection;
/* initialize telnet connection information */
telnet_connection->prompt = strdup("> ");
telnet_connection->prompt_visible = true;
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", 2);
}
/* the prompt is always placed at the line beginning */
telnet_write(connection, "\r", 1);
telnet_prompt(connection);
telnet_load_history(telnet_connection);
log_add_callback(telnet_log_callback, connection);
return ERROR_OK;
}
static void telnet_clear_line(struct connection *connection,
struct telnet_connection *t_con)
{
/* move to end of line */
if (t_con->line_cursor < t_con->line_size)
telnet_write(connection,
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) {
telnet_write(connection, "\b \b", 3);
t_con->line_size--;
}
t_con->line_cursor = 0;
}
static void telnet_history_go(struct connection *connection, int idx)
{
struct telnet_connection *t_con = connection->priv;
if (t_con->history[idx]) {
telnet_clear_line(connection, t_con);
t_con->line_size = strlen(t_con->history[idx]);
t_con->line_cursor = t_con->line_size;
memcpy(t_con->line, t_con->history[idx], t_con->line_size);
telnet_write(connection, t_con->line, t_con->line_size);
t_con->current_history = idx;
}
t_con->state = TELNET_STATE_DATA;
}
static void telnet_history_up(struct connection *connection)
{
struct telnet_connection *t_con = connection->priv;
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);
}
static void telnet_history_down(struct connection *connection)
{
struct telnet_connection *t_con = connection->priv;
size_t next_history;
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;
bytes_read = connection_read(connection, buffer, TELNET_BUFFER_SIZE);
if (bytes_read == 0)
return ERROR_SERVER_REMOTE_CLOSED;
else if (bytes_read == -1) {
LOG_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 == 0xff) {
t_con->state = TELNET_STATE_IAC;
} else {
if (isprint(*buf_p)) { /* printable character */
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 */
int retval;
/* 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 ((bytes_read > 1) && (*(buf_p + 1) == 0)) {
buf_p++;
bytes_read--;
}
t_con->line[t_con->line_size] = 0;
retval = telnet_exec_line(connection);
if (retval != ERROR_OK)
return retval;
} else if ((*buf_p == 0x7f) || (*buf_p == 0x8)) { /* delete character */
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 */
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 */
telnet_move_cursor(connection, t_con->line_cursor + 1);
t_con->state = TELNET_STATE_DATA;
} else if (*buf_p == CTRL('P')) { /* cursor up */
telnet_history_up(connection);
} else if (*buf_p == CTRL('N')) { /* cursor down */
telnet_history_down(connection);
} 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;
case TELNET_STATE_IAC:
switch (*buf_p) {
case 0xfe:
t_con->state = TELNET_STATE_DONT;
break;
case 0xfd:
t_con->state = TELNET_STATE_DO;
break;
case 0xfc:
t_con->state = TELNET_STATE_WONT;
break;
case 0xfb:
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 */
telnet_move_cursor(connection, t_con->line_cursor - 1);
t_con->state = TELNET_STATE_DATA;
} else if (*buf_p == 'C') { /* cursor right */
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 == '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 {
t_con->state = TELNET_STATE_DATA;
}
} else if (t_con->last_escape == '3') {
/* Remove character */
if (*buf_p == '~') {
telnet_remove_character(connection);
t_con->state = TELNET_STATE_DATA;
} else
t_con->state = TELNET_STATE_DATA;
} else if (t_con->last_escape == '\x00') {
if (*buf_p == '[')
t_con->last_escape = *buf_p;
else
t_con->state = TELNET_STATE_DATA;
} else {
LOG_ERROR("BUG: unexpected value in t_con->last_escape");
t_con->state = TELNET_STATE_DATA;
}
break;
default:
LOG_ERROR("unknown telnet state");
return ERROR_FAIL;
}
bytes_read--;
buf_p++;
}
return ERROR_OK;
}
static int telnet_connection_closed(struct connection *connection)
{
struct telnet_connection *t_con = connection->priv;
int i;
log_remove_callback(telnet_log_callback, connection);
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++) {
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);
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) {
LOG_INFO("telnet server disabled");
return ERROR_OK;
}
struct telnet_service *telnet_service =
malloc(sizeof(struct telnet_service));
if (!telnet_service) {
LOG_ERROR("Failed to allocate telnet service.");
return ERROR_FAIL;
}
telnet_service->banner = banner;
int ret = add_service(&telnet_service_driver, telnet_port, CONNECTION_LIMIT_UNLIMITED,
telnet_service);
if (ret != ERROR_OK) {
free(telnet_service);
return ret;
}
return ERROR_OK;
}
/* daemon configuration command telnet_port */
COMMAND_HANDLER(handle_telnet_port_command)
{
return CALL_COMMAND_HANDLER(server_pipe_command, &telnet_port);
}
COMMAND_HANDLER(handle_exit_command)
{
return ERROR_COMMAND_CLOSE_CONNECTION;
}
static const struct command_registration telnet_command_handlers[] = {
{
.name = "exit",
.handler = handle_exit_command,
.mode = COMMAND_EXEC,
.usage = "",
.help = "exit telnet session",
},
{
.name = "telnet_port",
.handler = handle_telnet_port_command,
.mode = COMMAND_CONFIG,
.help = "Specify port on which to listen "
"for incoming telnet connections. "
"Read help on 'gdb_port'.",
.usage = "[port_num]",
},
COMMAND_REGISTRATION_DONE
};
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);
}
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