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openocd/src/server/telnet_server.c
Andreas Fritiofson 517ba0690d Clean up const usage to avoid excessive casting 
Don't use const on pointers that hold heap allocated data, because that
means functions that free them must cast away the const.

Do use const on pointer parameters or fields that needn't be modified.

Remove pointer casts that are no longer needed after fixing the constness.

Change-Id: I5d206f5019982fd1950bc6d6d07b6062dc24e886
Signed-off-by: Andreas Fritiofson <andreas.fritiofson@gmail.com>
Reviewed-on: http://openocd.zylin.com/1668
Tested-by: jenkins
Reviewed-by: Mathias Küster <kesmtp@freenet.de>
Reviewed-by: Spencer Oliver <spen@spen-soft.co.uk>
2013-10-31 20:42:34 +00:00

671 lines
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/***************************************************************************
* 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 *
* *
* 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., *
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. *
***************************************************************************/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "telnet_server.h"
#include <target/target_request.h>
#include <helper/configuration.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 = 1;
return ERROR_SERVER_REMOTE_CLOSED;
}
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;
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 */
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);
/* 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);
for (i = t_con->line_size; i > t_con->line_cursor; 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 == NULL) {
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) != NULL) {
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 == NULL) {
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] == NULL && 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 = malloc(sizeof(struct telnet_connection));
struct telnet_service *telnet_service = connection->service->priv;
int i;
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->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);
/* 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);
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;
int 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;
int next_history = (t_con->current_history + 1) % TELNET_LINE_HISTORY_SIZE;
telnet_history_go(connection, next_history);
}
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);
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 */
/* 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 */
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;
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;
} 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_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--;
}
t_con->state = TELNET_STATE_DATA;
} 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);
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
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 */
if (t_con->line_cursor > 0) {
telnet_write(connection, "\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)
telnet_write(connection,
t_con->line + 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')
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 */
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
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");
exit(-1);
}
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);
if (t_con->prompt) {
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;
}
}
/* 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");
return ERROR_OK;
}
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));
telnet_service->banner = banner;
return add_service("telnet",
telnet_port,
1,
telnet_new_connection,
telnet_input,
telnet_connection_closed,
telnet_service);
}
/* 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_ANY,
.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);
}
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