hostap/wpa_supplicant/dbus/dbus_old.c
Jouni Malinen a17539ebcd Remove unnecessary include file inclusion
Signed-hostap: Jouni Malinen <j@w1.fi>
2011-11-13 22:13:04 +02:00

749 lines
22 KiB
C

/*
* WPA Supplicant / dbus-based control interface
* Copyright (c) 2006, Dan Williams <dcbw@redhat.com> and Red Hat, Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* Alternatively, this software may be distributed under the terms of BSD
* license.
*
* See README and COPYING for more details.
*/
#include "includes.h"
#include <dbus/dbus.h>
#include "common.h"
#include "eloop.h"
#include "wps/wps.h"
#include "../config.h"
#include "../wpa_supplicant_i.h"
#include "../bss.h"
#include "dbus_old.h"
#include "dbus_old_handlers.h"
#include "dbus_common_i.h"
/**
* wpas_dbus_decompose_object_path - Decompose an interface object path into parts
* @path: The dbus object path
* @network: (out) the configured network this object path refers to, if any
* @bssid: (out) the scanned bssid this object path refers to, if any
* Returns: The object path of the network interface this path refers to
*
* For a given object path, decomposes the object path into object id, network,
* and BSSID parts, if those parts exist.
*/
char * wpas_dbus_decompose_object_path(const char *path, char **network,
char **bssid)
{
const unsigned int dev_path_prefix_len =
strlen(WPAS_DBUS_PATH_INTERFACES "/");
char *obj_path_only;
char *next_sep;
/* Be a bit paranoid about path */
if (!path || strncmp(path, WPAS_DBUS_PATH_INTERFACES "/",
dev_path_prefix_len))
return NULL;
/* Ensure there's something at the end of the path */
if ((path + dev_path_prefix_len)[0] == '\0')
return NULL;
obj_path_only = os_strdup(path);
if (obj_path_only == NULL)
return NULL;
next_sep = strchr(obj_path_only + dev_path_prefix_len, '/');
if (next_sep != NULL) {
const char *net_part = strstr(next_sep,
WPAS_DBUS_NETWORKS_PART "/");
const char *bssid_part = strstr(next_sep,
WPAS_DBUS_BSSIDS_PART "/");
if (network && net_part) {
/* Deal with a request for a configured network */
const char *net_name = net_part +
strlen(WPAS_DBUS_NETWORKS_PART "/");
*network = NULL;
if (strlen(net_name))
*network = os_strdup(net_name);
} else if (bssid && bssid_part) {
/* Deal with a request for a scanned BSSID */
const char *bssid_name = bssid_part +
strlen(WPAS_DBUS_BSSIDS_PART "/");
if (strlen(bssid_name))
*bssid = os_strdup(bssid_name);
else
*bssid = NULL;
}
/* Cut off interface object path before "/" */
*next_sep = '\0';
}
return obj_path_only;
}
/**
* wpas_dbus_new_invalid_iface_error - Return a new invalid interface error message
* @message: Pointer to incoming dbus message this error refers to
* Returns: A dbus error message
*
* Convenience function to create and return an invalid interface error
*/
DBusMessage * wpas_dbus_new_invalid_iface_error(DBusMessage *message)
{
return dbus_message_new_error(message, WPAS_ERROR_INVALID_IFACE,
"wpa_supplicant knows nothing about "
"this interface.");
}
/**
* wpas_dbus_new_invalid_network_error - Return a new invalid network error message
* @message: Pointer to incoming dbus message this error refers to
* Returns: a dbus error message
*
* Convenience function to create and return an invalid network error
*/
DBusMessage * wpas_dbus_new_invalid_network_error(DBusMessage *message)
{
return dbus_message_new_error(message, WPAS_ERROR_INVALID_NETWORK,
"The requested network does not exist.");
}
/**
* wpas_dbus_new_invalid_bssid_error - Return a new invalid bssid error message
* @message: Pointer to incoming dbus message this error refers to
* Returns: a dbus error message
*
* Convenience function to create and return an invalid bssid error
*/
static DBusMessage * wpas_dbus_new_invalid_bssid_error(DBusMessage *message)
{
return dbus_message_new_error(message, WPAS_ERROR_INVALID_BSSID,
"The BSSID requested was invalid.");
}
/**
* wpas_dispatch_network_method - dispatch messages for configured networks
* @message: the incoming dbus message
* @wpa_s: a network interface's data
* @network_id: id of the configured network we're interested in
* Returns: a reply dbus message, or a dbus error message
*
* This function dispatches all incoming dbus messages for configured networks.
*/
static DBusMessage * wpas_dispatch_network_method(DBusMessage *message,
struct wpa_supplicant *wpa_s,
int network_id)
{
DBusMessage *reply = NULL;
const char *method = dbus_message_get_member(message);
struct wpa_ssid *ssid;
ssid = wpa_config_get_network(wpa_s->conf, network_id);
if (ssid == NULL)
return wpas_dbus_new_invalid_network_error(message);
if (!strcmp(method, "set"))
reply = wpas_dbus_iface_set_network(message, wpa_s, ssid);
else if (!strcmp(method, "enable"))
reply = wpas_dbus_iface_enable_network(message, wpa_s, ssid);
else if (!strcmp(method, "disable"))
reply = wpas_dbus_iface_disable_network(message, wpa_s, ssid);
return reply;
}
/**
* wpas_dispatch_bssid_method - dispatch messages for scanned networks
* @message: the incoming dbus message
* @wpa_s: a network interface's data
* @bssid: bssid of the scanned network we're interested in
* Returns: a reply dbus message, or a dbus error message
*
* This function dispatches all incoming dbus messages for scanned networks.
*/
static DBusMessage * wpas_dispatch_bssid_method(DBusMessage *message,
struct wpa_supplicant *wpa_s,
const char *bssid_txt)
{
u8 bssid[ETH_ALEN];
struct wpa_bss *bss;
if (hexstr2bin(bssid_txt, bssid, ETH_ALEN) < 0)
return wpas_dbus_new_invalid_bssid_error(message);
bss = wpa_bss_get_bssid(wpa_s, bssid);
if (bss == NULL)
return wpas_dbus_new_invalid_bssid_error(message);
/* Dispatch the method call against the scanned bssid */
if (os_strcmp(dbus_message_get_member(message), "properties") == 0)
return wpas_dbus_bssid_properties(message, wpa_s, bss);
return NULL;
}
/**
* wpas_iface_message_handler - Dispatch messages for interfaces or networks
* @connection: Connection to the system message bus
* @message: An incoming dbus message
* @user_data: A pointer to a dbus control interface data structure
* Returns: Whether or not the message was handled
*
* This function dispatches all incoming dbus messages for network interfaces,
* or objects owned by them, such as scanned BSSIDs and configured networks.
*/
static DBusHandlerResult wpas_iface_message_handler(DBusConnection *connection,
DBusMessage *message,
void *user_data)
{
struct wpa_supplicant *wpa_s = user_data;
const char *method = dbus_message_get_member(message);
const char *path = dbus_message_get_path(message);
const char *msg_interface = dbus_message_get_interface(message);
char *iface_obj_path = NULL;
char *network = NULL;
char *bssid = NULL;
DBusMessage *reply = NULL;
/* Caller must specify a message interface */
if (!msg_interface)
goto out;
iface_obj_path = wpas_dbus_decompose_object_path(path, &network,
&bssid);
if (iface_obj_path == NULL) {
reply = wpas_dbus_new_invalid_iface_error(message);
goto out;
}
/* Make sure the message's object path actually refers to the
* wpa_supplicant structure it's supposed to (which is wpa_s)
*/
if (wpa_supplicant_get_iface_by_dbus_path(wpa_s->global,
iface_obj_path) != wpa_s) {
reply = wpas_dbus_new_invalid_iface_error(message);
goto out;
}
if (network && !strcmp(msg_interface, WPAS_DBUS_IFACE_NETWORK)) {
/* A method for one of this interface's configured networks */
int nid = strtoul(network, NULL, 10);
if (errno != EINVAL)
reply = wpas_dispatch_network_method(message, wpa_s,
nid);
else
reply = wpas_dbus_new_invalid_network_error(message);
} else if (bssid && !strcmp(msg_interface, WPAS_DBUS_IFACE_BSSID)) {
/* A method for one of this interface's scanned BSSIDs */
reply = wpas_dispatch_bssid_method(message, wpa_s, bssid);
} else if (!strcmp(msg_interface, WPAS_DBUS_IFACE_INTERFACE)) {
/* A method for an interface only. */
if (!strcmp(method, "scan"))
reply = wpas_dbus_iface_scan(message, wpa_s);
else if (!strcmp(method, "scanResults"))
reply = wpas_dbus_iface_scan_results(message, wpa_s);
else if (!strcmp(method, "addNetwork"))
reply = wpas_dbus_iface_add_network(message, wpa_s);
else if (!strcmp(method, "removeNetwork"))
reply = wpas_dbus_iface_remove_network(message, wpa_s);
else if (!strcmp(method, "selectNetwork"))
reply = wpas_dbus_iface_select_network(message, wpa_s);
else if (!strcmp(method, "capabilities"))
reply = wpas_dbus_iface_capabilities(message, wpa_s);
else if (!strcmp(method, "disconnect"))
reply = wpas_dbus_iface_disconnect(message, wpa_s);
else if (!strcmp(method, "setAPScan"))
reply = wpas_dbus_iface_set_ap_scan(message, wpa_s);
else if (!strcmp(method, "setSmartcardModules"))
reply = wpas_dbus_iface_set_smartcard_modules(message,
wpa_s);
else if (!strcmp(method, "state"))
reply = wpas_dbus_iface_get_state(message, wpa_s);
else if (!strcmp(method, "scanning"))
reply = wpas_dbus_iface_get_scanning(message, wpa_s);
else if (!strcmp(method, "setBlobs"))
reply = wpas_dbus_iface_set_blobs(message, wpa_s);
else if (!strcmp(method, "removeBlobs"))
reply = wpas_dbus_iface_remove_blobs(message, wpa_s);
#ifdef CONFIG_WPS
else if (!os_strcmp(method, "wpsPbc"))
reply = wpas_dbus_iface_wps_pbc(message, wpa_s);
else if (!os_strcmp(method, "wpsPin"))
reply = wpas_dbus_iface_wps_pin(message, wpa_s);
else if (!os_strcmp(method, "wpsReg"))
reply = wpas_dbus_iface_wps_reg(message, wpa_s);
#endif /* CONFIG_WPS */
else if (!os_strcmp(method, "flush"))
reply = wpas_dbus_iface_flush(message, wpa_s);
}
/* If the message was handled, send back the reply */
if (reply) {
if (!dbus_message_get_no_reply(message))
dbus_connection_send(connection, reply, NULL);
dbus_message_unref(reply);
}
out:
os_free(iface_obj_path);
os_free(network);
os_free(bssid);
return reply ? DBUS_HANDLER_RESULT_HANDLED :
DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
}
/**
* wpas_message_handler - dispatch incoming dbus messages
* @connection: connection to the system message bus
* @message: an incoming dbus message
* @user_data: a pointer to a dbus control interface data structure
* Returns: whether or not the message was handled
*
* This function dispatches all incoming dbus messages to the correct
* handlers, depending on what the message's target object path is,
* and what the method call is.
*/
static DBusHandlerResult wpas_message_handler(DBusConnection *connection,
DBusMessage *message, void *user_data)
{
struct wpas_dbus_priv *ctrl_iface = user_data;
const char *method;
const char *path;
const char *msg_interface;
DBusMessage *reply = NULL;
method = dbus_message_get_member(message);
path = dbus_message_get_path(message);
msg_interface = dbus_message_get_interface(message);
if (!method || !path || !ctrl_iface || !msg_interface)
return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
/* Validate the method interface */
if (strcmp(msg_interface, WPAS_DBUS_INTERFACE) != 0)
return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
if (!strcmp(path, WPAS_DBUS_PATH)) {
/* dispatch methods against our global dbus interface here */
if (!strcmp(method, "addInterface")) {
reply = wpas_dbus_global_add_interface(
message, ctrl_iface->global);
} else if (!strcmp(method, "removeInterface")) {
reply = wpas_dbus_global_remove_interface(
message, ctrl_iface->global);
} else if (!strcmp(method, "getInterface")) {
reply = wpas_dbus_global_get_interface(
message, ctrl_iface->global);
} else if (!strcmp(method, "setDebugParams")) {
reply = wpas_dbus_global_set_debugparams(
message, ctrl_iface->global);
}
}
/* If the message was handled, send back the reply */
if (reply) {
if (!dbus_message_get_no_reply(message))
dbus_connection_send(connection, reply, NULL);
dbus_message_unref(reply);
}
return reply ? DBUS_HANDLER_RESULT_HANDLED :
DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
}
/**
* wpa_supplicant_dbus_notify_scan_results - Send a scan results signal
* @wpa_s: %wpa_supplicant network interface data
* Returns: 0 on success, -1 on failure
*
* Notify listeners that this interface has updated scan results.
*/
void wpa_supplicant_dbus_notify_scan_results(struct wpa_supplicant *wpa_s)
{
struct wpas_dbus_priv *iface = wpa_s->global->dbus;
DBusMessage *_signal;
/* Do nothing if the control interface is not turned on */
if (iface == NULL)
return;
_signal = dbus_message_new_signal(wpa_s->dbus_path,
WPAS_DBUS_IFACE_INTERFACE,
"ScanResultsAvailable");
if (_signal == NULL) {
wpa_printf(MSG_ERROR, "dbus: Not enough memory to send scan "
"results signal");
return;
}
dbus_connection_send(iface->con, _signal, NULL);
dbus_message_unref(_signal);
}
/**
* wpa_supplicant_dbus_notify_state_change - Send a state change signal
* @wpa_s: %wpa_supplicant network interface data
* @new_state: new state wpa_supplicant is entering
* @old_state: old state wpa_supplicant is leaving
* Returns: 0 on success, -1 on failure
*
* Notify listeners that wpa_supplicant has changed state
*/
void wpa_supplicant_dbus_notify_state_change(struct wpa_supplicant *wpa_s,
enum wpa_states new_state,
enum wpa_states old_state)
{
struct wpas_dbus_priv *iface;
DBusMessage *_signal = NULL;
const char *new_state_str, *old_state_str;
if (wpa_s->dbus_path == NULL)
return; /* Skip signal since D-Bus setup is not yet ready */
/* Do nothing if the control interface is not turned on */
if (wpa_s->global == NULL)
return;
iface = wpa_s->global->dbus;
if (iface == NULL)
return;
/* Only send signal if state really changed */
if (new_state == old_state)
return;
_signal = dbus_message_new_signal(wpa_s->dbus_path,
WPAS_DBUS_IFACE_INTERFACE,
"StateChange");
if (_signal == NULL) {
wpa_printf(MSG_ERROR,
"dbus: wpa_supplicant_dbus_notify_state_change: "
"could not create dbus signal; likely out of "
"memory");
return;
}
new_state_str = wpa_supplicant_state_txt(new_state);
old_state_str = wpa_supplicant_state_txt(old_state);
if (new_state_str == NULL || old_state_str == NULL) {
wpa_printf(MSG_ERROR,
"dbus: wpa_supplicant_dbus_notify_state_change: "
"Could not convert state strings");
goto out;
}
if (!dbus_message_append_args(_signal,
DBUS_TYPE_STRING, &new_state_str,
DBUS_TYPE_STRING, &old_state_str,
DBUS_TYPE_INVALID)) {
wpa_printf(MSG_ERROR,
"dbus: wpa_supplicant_dbus_notify_state_change: "
"Not enough memory to construct state change "
"signal");
goto out;
}
dbus_connection_send(iface->con, _signal, NULL);
out:
dbus_message_unref(_signal);
}
/**
* wpa_supplicant_dbus_notify_scanning - send scanning status
* @wpa_s: %wpa_supplicant network interface data
* Returns: 0 on success, -1 on failure
*
* Notify listeners of interface scanning state changes
*/
void wpa_supplicant_dbus_notify_scanning(struct wpa_supplicant *wpa_s)
{
struct wpas_dbus_priv *iface = wpa_s->global->dbus;
DBusMessage *_signal;
dbus_bool_t scanning = wpa_s->scanning ? TRUE : FALSE;
/* Do nothing if the control interface is not turned on */
if (iface == NULL)
return;
_signal = dbus_message_new_signal(wpa_s->dbus_path,
WPAS_DBUS_IFACE_INTERFACE,
"Scanning");
if (_signal == NULL) {
wpa_printf(MSG_ERROR, "dbus: Not enough memory to send scan "
"results signal");
return;
}
if (dbus_message_append_args(_signal,
DBUS_TYPE_BOOLEAN, &scanning,
DBUS_TYPE_INVALID)) {
dbus_connection_send(iface->con, _signal, NULL);
} else {
wpa_printf(MSG_ERROR, "dbus: Not enough memory to construct "
"signal");
}
dbus_message_unref(_signal);
}
#ifdef CONFIG_WPS
void wpa_supplicant_dbus_notify_wps_cred(struct wpa_supplicant *wpa_s,
const struct wps_credential *cred)
{
struct wpas_dbus_priv *iface;
DBusMessage *_signal = NULL;
/* Do nothing if the control interface is not turned on */
if (wpa_s->global == NULL)
return;
iface = wpa_s->global->dbus;
if (iface == NULL)
return;
_signal = dbus_message_new_signal(wpa_s->dbus_path,
WPAS_DBUS_IFACE_INTERFACE,
"WpsCred");
if (_signal == NULL) {
wpa_printf(MSG_ERROR,
"dbus: wpa_supplicant_dbus_notify_wps_cred: "
"Could not create dbus signal; likely out of "
"memory");
return;
}
if (!dbus_message_append_args(_signal,
DBUS_TYPE_ARRAY, DBUS_TYPE_BYTE,
&cred->cred_attr, cred->cred_attr_len,
DBUS_TYPE_INVALID)) {
wpa_printf(MSG_ERROR,
"dbus: wpa_supplicant_dbus_notify_wps_cred: "
"Not enough memory to construct signal");
goto out;
}
dbus_connection_send(iface->con, _signal, NULL);
out:
dbus_message_unref(_signal);
}
#else /* CONFIG_WPS */
void wpa_supplicant_dbus_notify_wps_cred(struct wpa_supplicant *wpa_s,
const struct wps_credential *cred)
{
}
#endif /* CONFIG_WPS */
void wpa_supplicant_dbus_notify_certification(struct wpa_supplicant *wpa_s,
int depth, const char *subject,
const char *cert_hash,
const struct wpabuf *cert)
{
struct wpas_dbus_priv *iface;
DBusMessage *_signal = NULL;
const char *hash;
const char *cert_hex;
int cert_hex_len;
/* Do nothing if the control interface is not turned on */
if (wpa_s->global == NULL)
return;
iface = wpa_s->global->dbus;
if (iface == NULL)
return;
_signal = dbus_message_new_signal(wpa_s->dbus_path,
WPAS_DBUS_IFACE_INTERFACE,
"Certification");
if (_signal == NULL) {
wpa_printf(MSG_ERROR,
"dbus: wpa_supplicant_dbus_notify_certification: "
"Could not create dbus signal; likely out of "
"memory");
return;
}
hash = cert_hash ? cert_hash : "";
cert_hex = cert ? wpabuf_head(cert) : "";
cert_hex_len = cert ? wpabuf_len(cert) : 0;
if (!dbus_message_append_args(_signal,
DBUS_TYPE_INT32,&depth,
DBUS_TYPE_STRING, &subject,
DBUS_TYPE_STRING, &hash,
DBUS_TYPE_ARRAY, DBUS_TYPE_BYTE,
&cert_hex, cert_hex_len,
DBUS_TYPE_INVALID)) {
wpa_printf(MSG_ERROR,
"dbus: wpa_supplicant_dbus_notify_certification: "
"Not enough memory to construct signal");
goto out;
}
dbus_connection_send(iface->con, _signal, NULL);
out:
dbus_message_unref(_signal);
}
/**
* wpa_supplicant_dbus_ctrl_iface_init - Initialize dbus control interface
* @global: Pointer to global data from wpa_supplicant_init()
* Returns: 0 on success, -1 on failure
*
* Initialize the dbus control interface and start receiving commands from
* external programs over the bus.
*/
int wpa_supplicant_dbus_ctrl_iface_init(struct wpas_dbus_priv *iface)
{
DBusError error;
int ret = -1;
DBusObjectPathVTable wpas_vtable = {
NULL, &wpas_message_handler, NULL, NULL, NULL, NULL
};
/* Register the message handler for the global dbus interface */
if (!dbus_connection_register_object_path(iface->con,
WPAS_DBUS_PATH, &wpas_vtable,
iface)) {
wpa_printf(MSG_ERROR, "dbus: Could not set up message "
"handler");
return -1;
}
/* Register our service with the message bus */
dbus_error_init(&error);
switch (dbus_bus_request_name(iface->con, WPAS_DBUS_SERVICE,
0, &error)) {
case DBUS_REQUEST_NAME_REPLY_PRIMARY_OWNER:
ret = 0;
break;
case DBUS_REQUEST_NAME_REPLY_EXISTS:
case DBUS_REQUEST_NAME_REPLY_IN_QUEUE:
case DBUS_REQUEST_NAME_REPLY_ALREADY_OWNER:
wpa_printf(MSG_ERROR, "dbus: Could not request service name: "
"already registered");
break;
default:
wpa_printf(MSG_ERROR, "dbus: Could not request service name: "
"%s %s", error.name, error.message);
break;
}
dbus_error_free(&error);
if (ret != 0)
return -1;
wpa_printf(MSG_DEBUG, "Providing DBus service '" WPAS_DBUS_SERVICE
"'.");
return 0;
}
/**
* wpas_dbus_register_new_iface - Register a new interface with dbus
* @wpa_s: %wpa_supplicant interface description structure to register
* Returns: 0 on success, -1 on error
*
* Registers a new interface with dbus and assigns it a dbus object path.
*/
int wpas_dbus_register_iface(struct wpa_supplicant *wpa_s)
{
struct wpas_dbus_priv *ctrl_iface = wpa_s->global->dbus;
DBusConnection * con;
u32 next;
DBusObjectPathVTable vtable = {
NULL, &wpas_iface_message_handler, NULL, NULL, NULL, NULL
};
/* Do nothing if the control interface is not turned on */
if (ctrl_iface == NULL)
return 0;
con = ctrl_iface->con;
next = ctrl_iface->next_objid++;
/* Create and set the interface's object path */
wpa_s->dbus_path = os_zalloc(WPAS_DBUS_OBJECT_PATH_MAX);
if (wpa_s->dbus_path == NULL)
return -1;
os_snprintf(wpa_s->dbus_path, WPAS_DBUS_OBJECT_PATH_MAX,
WPAS_DBUS_PATH_INTERFACES "/%u",
next);
/* Register the message handler for the interface functions */
if (!dbus_connection_register_fallback(con, wpa_s->dbus_path, &vtable,
wpa_s)) {
wpa_printf(MSG_ERROR, "dbus: Could not set up message "
"handler for interface %s", wpa_s->ifname);
return -1;
}
return 0;
}
/**
* wpas_dbus_unregister_iface - Unregister an interface from dbus
* @wpa_s: wpa_supplicant interface structure
* Returns: 0 on success, -1 on failure
*
* Unregisters the interface with dbus
*/
int wpas_dbus_unregister_iface(struct wpa_supplicant *wpa_s)
{
struct wpas_dbus_priv *ctrl_iface;
DBusConnection *con;
/* Do nothing if the control interface is not turned on */
if (wpa_s == NULL || wpa_s->global == NULL)
return 0;
ctrl_iface = wpa_s->global->dbus;
if (ctrl_iface == NULL)
return 0;
con = ctrl_iface->con;
if (!dbus_connection_unregister_object_path(con, wpa_s->dbus_path))
return -1;
os_free(wpa_s->dbus_path);
wpa_s->dbus_path = NULL;
return 0;
}
/**
* wpa_supplicant_get_iface_by_dbus_path - Get a new network interface
* @global: Pointer to global data from wpa_supplicant_init()
* @path: Pointer to a dbus object path representing an interface
* Returns: Pointer to the interface or %NULL if not found
*/
struct wpa_supplicant * wpa_supplicant_get_iface_by_dbus_path(
struct wpa_global *global, const char *path)
{
struct wpa_supplicant *wpa_s;
for (wpa_s = global->ifaces; wpa_s; wpa_s = wpa_s->next) {
if (strcmp(wpa_s->dbus_path, path) == 0)
return wpa_s;
}
return NULL;
}