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-rw-r--r--src/server/telnet_server.c154
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;
}