pbx.c

		ast_mutex_unlock(&hintlock);
		return -1;
	}
	memset(cblist, 0, sizeof(struct ast_state_cb));
	cblist->id = stateid++;		/* Unique ID for this callback */
	cblist->callback = callback;	/* Pointer to callback routine */
	cblist->data = data;		/* Data for the callback */

	cblist->next = list->callbacks;
	list->callbacks = cblist;

	ast_mutex_unlock(&hintlock);
	return cblist->id;
}

/*! \brief  ast_extension_state_del: Remove a watcher from the callback list */
int ast_extension_state_del(int id, ast_state_cb_type callback)
{
	struct ast_hint *list;
	struct ast_state_cb *cblist, *cbprev;

	if (!id && !callback)
		return -1;

	ast_mutex_lock(&hintlock);

	/* id is zero is a callback without extension */
	if (!id) {
		cbprev = NULL;
		cblist = statecbs;
		while (cblist) {
	 		if (cblist->callback == callback) {
				if (!cbprev)
		    			statecbs = cblist->next;
				else
		    			cbprev->next = cblist->next;

				free(cblist);

	        		ast_mutex_unlock(&hintlock);
				return 0;
	    		}
	    		cbprev = cblist;
	    		cblist = cblist->next;
		}

		ast_mutex_lock(&hintlock);
		return -1;
	}

	/* id greater than zero is a callback with extension */
	/* Find the callback based on ID */
	list = hints;
	while (list) {
		cblist = list->callbacks;
		cbprev = NULL;
		while (cblist) {
	    		if (cblist->id==id) {
				if (!cbprev)
		    			list->callbacks = cblist->next;		
				else
		    			cbprev->next = cblist->next;
		
				free(cblist);
		
				ast_mutex_unlock(&hintlock);
				return 0;		
	    		}		
	    		cbprev = cblist;				
	    		cblist = cblist->next;
		}
		list = list->next;
	}

	ast_mutex_unlock(&hintlock);
	return -1;
}

/*! \brief  ast_add_hint: Add hint to hint list, check initial extension state */
static int ast_add_hint(struct ast_exten *e)
{
	struct ast_hint *list;

	if (!e) 
		return -1;

	ast_mutex_lock(&hintlock);
	list = hints;        

	/* Search if hint exists, do nothing */
	while (list) {
		if (list->exten == e) {
			ast_mutex_unlock(&hintlock);
			if (option_debug > 1)
				ast_log(LOG_DEBUG, "HINTS: Not re-adding existing hint %s: %s\n", ast_get_extension_name(e), ast_get_extension_app(e));
			return -1;
		}
		list = list->next;    
	}

	if (option_debug > 1)
		ast_log(LOG_DEBUG, "HINTS: Adding hint %s: %s\n", ast_get_extension_name(e), ast_get_extension_app(e));

	list = malloc(sizeof(struct ast_hint));
	if (!list) {
		ast_mutex_unlock(&hintlock);
		if (option_debug > 1)
			ast_log(LOG_DEBUG, "HINTS: Out of memory...\n");
		return -1;
	}
	/* Initialize and insert new item at the top */
	memset(list, 0, sizeof(struct ast_hint));
	list->exten = e;
	list->laststate = ast_extension_state2(e);
	list->next = hints;
	hints = list;

	ast_mutex_unlock(&hintlock);
	return 0;
}

/*! \brief  ast_change_hint: Change hint for an extension */
static int ast_change_hint(struct ast_exten *oe, struct ast_exten *ne)
{ 
	struct ast_hint *list;

	ast_mutex_lock(&hintlock);
	list = hints;

	while(list) {
		if (list->exten == oe) {
	    		list->exten = ne;
			ast_mutex_unlock(&hintlock);	
			return 0;
		}
		list = list->next;
	}
	ast_mutex_unlock(&hintlock);

	return -1;
}

/*! \brief  ast_remove_hint: Remove hint from extension */
static int ast_remove_hint(struct ast_exten *e)
{
	/* Cleanup the Notifys if hint is removed */
	struct ast_hint *list, *prev = NULL;
	struct ast_state_cb *cblist, *cbprev;

	if (!e) 
		return -1;

	ast_mutex_lock(&hintlock);

	list = hints;    
	while(list) {
		if (list->exten==e) {
			cbprev = NULL;
			cblist = list->callbacks;
			while (cblist) {
				/* Notify with -1 and remove all callbacks */
				cbprev = cblist;	    
				cblist = cblist->next;
				cbprev->callback(list->exten->parent->name, list->exten->exten, AST_EXTENSION_DEACTIVATED, cbprev->data);
				free(cbprev);
	    		}
	    		list->callbacks = NULL;

	    		if (!prev)
				hints = list->next;
	    		else
				prev->next = list->next;
	    		free(list);
	    
			ast_mutex_unlock(&hintlock);
			return 0;
		} else {
			prev = list;
			list = list->next;    
		}
	}

	ast_mutex_unlock(&hintlock);
	return -1;
}


/*! \brief  ast_get_hint: Get hint for channel */
int ast_get_hint(char *hint, int hintsize, char *name, int namesize, struct ast_channel *c, const char *context, const char *exten)
{
	struct ast_exten *e;
	void *tmp;

	e = ast_hint_extension(c, context, exten);
	if (e) {
		if (hint) 
		    ast_copy_string(hint, ast_get_extension_app(e), hintsize);
		if (name) {
			tmp = ast_get_extension_app_data(e);
			if (tmp)
				ast_copy_string(name, (char *) tmp, namesize);
		}
	    return -1;
	}
	return 0;	
}

int ast_exists_extension(struct ast_channel *c, const char *context, const char *exten, int priority, const char *callerid) 
{
	return pbx_extension_helper(c, NULL, context, exten, priority, NULL, callerid, HELPER_EXISTS);
}

int ast_findlabel_extension(struct ast_channel *c, const char *context, const char *exten, const char *label, const char *callerid) 
{
	return pbx_extension_helper(c, NULL, context, exten, 0, label, callerid, HELPER_FINDLABEL);
}

int ast_findlabel_extension2(struct ast_channel *c, struct ast_context *con, const char *exten, const char *label, const char *callerid) 
{
	return pbx_extension_helper(c, con, NULL, exten, 0, label, callerid, HELPER_FINDLABEL);
}

int ast_canmatch_extension(struct ast_channel *c, const char *context, const char *exten, int priority, const char *callerid)
{
	return pbx_extension_helper(c, NULL, context, exten, priority, NULL, callerid, HELPER_CANMATCH);
}

int ast_matchmore_extension(struct ast_channel *c, const char *context, const char *exten, int priority, const char *callerid)
{
	return pbx_extension_helper(c, NULL, context, exten, priority, NULL, callerid, HELPER_MATCHMORE);
}

int ast_spawn_extension(struct ast_channel *c, const char *context, const char *exten, int priority, const char *callerid) 
{
	return pbx_extension_helper(c, NULL, context, exten, priority, NULL, callerid, HELPER_SPAWN);
}

int ast_exec_extension(struct ast_channel *c, const char *context, const char *exten, int priority, const char *callerid) 
{
	return pbx_extension_helper(c, NULL, context, exten, priority, NULL, callerid, HELPER_EXEC);
}

static int __ast_pbx_run(struct ast_channel *c)
{
	int firstpass = 1;
	int digit;
	char exten[256];
	int pos;
	int waittime;
	int res=0;
	int autoloopflag;

	/* A little initial setup here */
	if (c->pbx)
		ast_log(LOG_WARNING, "%s already has PBX structure??\n", c->name);
	c->pbx = malloc(sizeof(struct ast_pbx));
	if (!c->pbx) {
		ast_log(LOG_ERROR, "Out of memory\n");
		return -1;
	}
	if (c->amaflags) {
		if (!c->cdr) {
			c->cdr = ast_cdr_alloc();
			if (!c->cdr) {
				ast_log(LOG_WARNING, "Unable to create Call Detail Record\n");
				free(c->pbx);
				return -1;
			}
			ast_cdr_init(c->cdr, c);
		}
	}
	memset(c->pbx, 0, sizeof(struct ast_pbx));
	/* Set reasonable defaults */
	c->pbx->rtimeout = 10;
	c->pbx->dtimeout = 5;

	autoloopflag = ast_test_flag(c, AST_FLAG_IN_AUTOLOOP);
	ast_set_flag(c, AST_FLAG_IN_AUTOLOOP);

	/* Start by trying whatever the channel is set to */
	if (!ast_exists_extension(c, c->context, c->exten, c->priority, c->cid.cid_num)) {
		/* If not successful fall back to 's' */
		if (option_verbose > 1)
			ast_verbose( VERBOSE_PREFIX_2 "Starting %s at %s,%s,%d failed so falling back to exten 's'\n", c->name, c->context, c->exten, c->priority);
		ast_copy_string(c->exten, "s", sizeof(c->exten));
		if (!ast_exists_extension(c, c->context, c->exten, c->priority, c->cid.cid_num)) {
			/* JK02: And finally back to default if everything else failed */
			if (option_verbose > 1)
				ast_verbose( VERBOSE_PREFIX_2 "Starting %s at %s,%s,%d still failed so falling back to context 'default'\n", c->name, c->context, c->exten, c->priority);
			ast_copy_string(c->context, "default", sizeof(c->context));
		}
		c->priority = 1;
	}
	if (c->cdr && !c->cdr->start.tv_sec && !c->cdr->start.tv_usec)
		ast_cdr_start(c->cdr);
	for(;;) {
		pos = 0;
		digit = 0;
		while(ast_exists_extension(c, c->context, c->exten, c->priority, c->cid.cid_num)) {
			memset(exten, 0, sizeof(exten));
			if ((res = ast_spawn_extension(c, c->context, c->exten, c->priority, c->cid.cid_num))) {
				/* Something bad happened, or a hangup has been requested. */
				if (((res >= '0') && (res <= '9')) || ((res >= 'A') && (res <= 'F')) ||
					(res == '*') || (res == '#')) {
					ast_log(LOG_DEBUG, "Oooh, got something to jump out with ('%c')!\n", res);
					memset(exten, 0, sizeof(exten));
					pos = 0;
					exten[pos++] = digit = res;
					break;
				}
				switch(res) {
				case AST_PBX_KEEPALIVE:
					if (option_debug)
						ast_log(LOG_DEBUG, "Spawn extension (%s,%s,%d) exited KEEPALIVE on '%s'\n", c->context, c->exten, c->priority, c->name);
					else if (option_verbose > 1)
						ast_verbose( VERBOSE_PREFIX_2 "Spawn extension (%s, %s, %d) exited KEEPALIVE on '%s'\n", c->context, c->exten, c->priority, c->name);
					goto out;
					break;
				default:
					if (option_debug)
						ast_log(LOG_DEBUG, "Spawn extension (%s,%s,%d) exited non-zero on '%s'\n", c->context, c->exten, c->priority, c->name);
					else if (option_verbose > 1)
						ast_verbose( VERBOSE_PREFIX_2 "Spawn extension (%s, %s, %d) exited non-zero on '%s'\n", c->context, c->exten, c->priority, c->name);
					if (c->_softhangup == AST_SOFTHANGUP_ASYNCGOTO) {
						c->_softhangup =0;
						break;
					}
					/* atimeout */
					if (c->_softhangup == AST_SOFTHANGUP_TIMEOUT) {
						break;
					}

					if (c->cdr) {
						ast_cdr_update(c);
					}
					goto out;
				}
			}
			if ((c->_softhangup == AST_SOFTHANGUP_TIMEOUT) && (ast_exists_extension(c,c->context,"T",1,c->cid.cid_num))) {
				ast_copy_string(c->exten, "T", sizeof(c->exten));
				/* If the AbsoluteTimeout is not reset to 0, we'll get an infinite loop */
				c->whentohangup = 0;
				c->priority = 0;
				c->_softhangup &= ~AST_SOFTHANGUP_TIMEOUT;
			} else if (c->_softhangup) {
				ast_log(LOG_DEBUG, "Extension %s, priority %d returned normally even though call was hung up\n",
					c->exten, c->priority);
				goto out;
			}
			firstpass = 0;
			c->priority++;
		}
		if (!ast_exists_extension(c, c->context, c->exten, 1, c->cid.cid_num)) {
			/* It's not a valid extension anymore */
			if (ast_exists_extension(c, c->context, "i", 1, c->cid.cid_num)) {
				if (option_verbose > 2)
					ast_verbose(VERBOSE_PREFIX_3 "Sent into invalid extension '%s' in context '%s' on %s\n", c->exten, c->context, c->name);
				pbx_builtin_setvar_helper(c, "INVALID_EXTEN", c->exten);
				ast_copy_string(c->exten, "i", sizeof(c->exten));
				c->priority = 1;
			} else {
				ast_log(LOG_WARNING, "Channel '%s' sent into invalid extension '%s' in context '%s', but no invalid handler\n",
					c->name, c->exten, c->context);
				goto out;
			}
		} else if (c->_softhangup == AST_SOFTHANGUP_TIMEOUT) {
			/* If we get this far with AST_SOFTHANGUP_TIMEOUT, then we know that the "T" extension is next. */
			c->_softhangup = 0;
		} else {
			/* Done, wait for an extension */
			waittime = 0;
			if (digit)
				waittime = c->pbx->dtimeout;
			else if (!autofallthrough)
				waittime = c->pbx->rtimeout;
			if (waittime) {
				while (ast_matchmore_extension(c, c->context, exten, 1, c->cid.cid_num)) {
					/* As long as we're willing to wait, and as long as it's not defined, 
					   keep reading digits until we can't possibly get a right answer anymore.  */
					digit = ast_waitfordigit(c, waittime * 1000);
					if (c->_softhangup == AST_SOFTHANGUP_ASYNCGOTO) {
						c->_softhangup = 0;
					} else {
						if (!digit)
							/* No entry */
							break;
						if (digit < 0)
							/* Error, maybe a  hangup */
							goto out;
						exten[pos++] = digit;
						waittime = c->pbx->dtimeout;
					}
				}
				if (ast_exists_extension(c, c->context, exten, 1, c->cid.cid_num)) {
					/* Prepare the next cycle */
					ast_copy_string(c->exten, exten, sizeof(c->exten));
					c->priority = 1;
				} else {
					/* No such extension */
					if (!ast_strlen_zero(exten)) {
						/* An invalid extension */
						if (ast_exists_extension(c, c->context, "i", 1, c->cid.cid_num)) {
							if (option_verbose > 2)
								ast_verbose( VERBOSE_PREFIX_3 "Invalid extension '%s' in context '%s' on %s\n", exten, c->context, c->name);
							pbx_builtin_setvar_helper(c, "INVALID_EXTEN", exten);
							ast_copy_string(c->exten, "i", sizeof(c->exten));
							c->priority = 1;
						} else {
							ast_log(LOG_WARNING, "Invalid extension '%s', but no rule 'i' in context '%s'\n", exten, c->context);
							goto out;
						}
					} else {
						/* A simple timeout */
						if (ast_exists_extension(c, c->context, "t", 1, c->cid.cid_num)) {
							if (option_verbose > 2)
								ast_verbose( VERBOSE_PREFIX_3 "Timeout on %s\n", c->name);
							ast_copy_string(c->exten, "t", sizeof(c->exten));
							c->priority = 1;
						} else {
							ast_log(LOG_WARNING, "Timeout, but no rule 't' in context '%s'\n", c->context);
							goto out;
						}
					}	
				}
				if (c->cdr) {
					if (option_verbose > 2)
						ast_verbose(VERBOSE_PREFIX_2 "CDR updated on %s\n",c->name);	
					ast_cdr_update(c);
			    }
			} else {
				char *status;

				status = pbx_builtin_getvar_helper(c, "DIALSTATUS");
				if (!status)
					status = "UNKNOWN";
				if (option_verbose > 2)
					ast_verbose(VERBOSE_PREFIX_2 "Auto fallthrough, channel '%s' status is '%s'\n", c->name, status);
				if (!strcasecmp(status, "CONGESTION"))
					res = pbx_builtin_congestion(c, "10");
				else if (!strcasecmp(status, "CHANUNAVAIL"))
					res = pbx_builtin_congestion(c, "10");
				else if (!strcasecmp(status, "BUSY"))
					res = pbx_builtin_busy(c, "10");
				goto out;
			}
		}
	}
	if (firstpass) 
		ast_log(LOG_WARNING, "Don't know what to do with '%s'\n", c->name);
out:
	if ((res != AST_PBX_KEEPALIVE) && ast_exists_extension(c, c->context, "h", 1, c->cid.cid_num)) {
		c->exten[0] = 'h';
		c->exten[1] = '\0';
		c->priority = 1;
		while(ast_exists_extension(c, c->context, c->exten, c->priority, c->cid.cid_num)) {
			if ((res = ast_spawn_extension(c, c->context, c->exten, c->priority, c->cid.cid_num))) {
				/* Something bad happened, or a hangup has been requested. */
				if (option_debug)
					ast_log(LOG_DEBUG, "Spawn extension (%s,%s,%d) exited non-zero on '%s'\n", c->context, c->exten, c->priority, c->name);
				else if (option_verbose > 1)
					ast_verbose( VERBOSE_PREFIX_2 "Spawn extension (%s, %s, %d) exited non-zero on '%s'\n", c->context, c->exten, c->priority, c->name);
				break;
			}
			c->priority++;
		}
	}
	ast_set2_flag(c, autoloopflag, AST_FLAG_IN_AUTOLOOP);

	pbx_destroy(c->pbx);
	c->pbx = NULL;
	if (res != AST_PBX_KEEPALIVE)
		ast_hangup(c);
	return 0;
}

/* Returns 0 on success, non-zero if call limit was reached */
static int increase_call_count(const struct ast_channel *c)
{
	int failed = 0;
	double curloadavg;
	ast_mutex_lock(&maxcalllock);
	if (option_maxcalls) {
		if (countcalls >= option_maxcalls) {
			ast_log(LOG_NOTICE, "Maximum call limit of %d calls exceeded by '%s'!\n", option_maxcalls, c->name);
			failed = -1;
		}
	}
	if (option_maxload) {
		getloadavg(&curloadavg, 1);
		if (curloadavg >= option_maxload) {
			ast_log(LOG_NOTICE, "Maximum loadavg limit of %lf load exceeded by '%s' (currently %f)!\n", option_maxload, c->name, curloadavg);
			failed = -1;
		}
	}
	if (!failed)
		countcalls++;	
	ast_mutex_unlock(&maxcalllock);

	return failed;
}

static void decrease_call_count(void)
{
	ast_mutex_lock(&maxcalllock);
	if (countcalls > 0)
		countcalls--;
	ast_mutex_unlock(&maxcalllock);
}

static void *pbx_thread(void *data)
{
	/* Oh joyeous kernel, we're a new thread, with nothing to do but
	   answer this channel and get it going.
	*/
	/* NOTE:
	   The launcher of this function _MUST_ increment 'countcalls'
	   before invoking the function; it will be decremented when the
	   PBX has finished running on the channel
	 */
	struct ast_channel *c = data;

	__ast_pbx_run(c);
	decrease_call_count();

	pthread_exit(NULL);

	return NULL;
}

enum ast_pbx_result ast_pbx_start(struct ast_channel *c)
{
	pthread_t t;
	pthread_attr_t attr;

	if (!c) {
		ast_log(LOG_WARNING, "Asked to start thread on NULL channel?\n");
		return AST_PBX_FAILED;
	}
	   
	if (increase_call_count(c))
		return AST_PBX_CALL_LIMIT;

	/* Start a new thread, and get something handling this channel. */
	pthread_attr_init(&attr);
	pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
	if (ast_pthread_create(&t, &attr, pbx_thread, c)) {
		ast_log(LOG_WARNING, "Failed to create new channel thread\n");
		return AST_PBX_FAILED;
	}

	return AST_PBX_SUCCESS;
}

enum ast_pbx_result ast_pbx_run(struct ast_channel *c)
{
	enum ast_pbx_result res = AST_PBX_SUCCESS;

	if (increase_call_count(c))
		return AST_PBX_CALL_LIMIT;

	res = __ast_pbx_run(c);
	decrease_call_count();

	return res;
}

int ast_active_calls(void)
{
	return countcalls;
}

int pbx_set_autofallthrough(int newval)
{
	int oldval;
	oldval = autofallthrough;
	if (oldval != newval)
		autofallthrough = newval;
	return oldval;
}

/*
 * This function locks contexts list by &conlist, search for the right context
 * structure, leave context list locked and call ast_context_remove_include2
 * which removes include, unlock contexts list and return ...
 */
int ast_context_remove_include(const char *context, const char *include, const char *registrar)
{
	struct ast_context *c;

	if (ast_lock_contexts()) return -1;

	/* walk contexts and search for the right one ...*/
	c = ast_walk_contexts(NULL);
	while (c) {
		/* we found one ... */
		if (!strcmp(ast_get_context_name(c), context)) {
			int ret;
			/* remove include from this context ... */	
			ret = ast_context_remove_include2(c, include, registrar);

			ast_unlock_contexts();

			/* ... return results */
			return ret;
		}
		c = ast_walk_contexts(c);
	}

	/* we can't find the right one context */
	ast_unlock_contexts();
	return -1;
}

/*
 * When we call this function, &conlock lock must be locked, because when
 * we giving *con argument, some process can remove/change this context
 * and after that there can be segfault.
 *
 * This function locks given context, removes include, unlock context and
 * return.
 */
int ast_context_remove_include2(struct ast_context *con, const char *include, const char *registrar)
{
	struct ast_include *i, *pi = NULL;

	if (ast_mutex_lock(&con->lock)) return -1;

	/* walk includes */
	i = con->includes;
	while (i) {
		/* find our include */
		if (!strcmp(i->name, include) && 
			(!registrar || !strcmp(i->registrar, registrar))) {
			/* remove from list */
			if (pi)
				pi->next = i->next;
			else
				con->includes = i->next;
			/* free include and return */
			free(i);
			ast_mutex_unlock(&con->lock);
			return 0;
		}
		pi = i;
		i = i->next;
	}

	/* we can't find the right include */
	ast_mutex_unlock(&con->lock);
	return -1;
}

/*
 * This function locks contexts list by &conlist, search for the rigt context
 * structure, leave context list locked and call ast_context_remove_switch2
 * which removes switch, unlock contexts list and return ...
 */
int ast_context_remove_switch(const char *context, const char *sw, const char *data, const char *registrar)
{
	struct ast_context *c;

	if (ast_lock_contexts()) return -1;

	/* walk contexts and search for the right one ...*/
	c = ast_walk_contexts(NULL);
	while (c) {
		/* we found one ... */
		if (!strcmp(ast_get_context_name(c), context)) {
			int ret;
			/* remove switch from this context ... */	
			ret = ast_context_remove_switch2(c, sw, data, registrar);

			ast_unlock_contexts();

			/* ... return results */
			return ret;
		}
		c = ast_walk_contexts(c);
	}

	/* we can't find the right one context */
	ast_unlock_contexts();
	return -1;
}

/*
 * When we call this function, &conlock lock must be locked, because when
 * we giving *con argument, some process can remove/change this context
 * and after that there can be segfault.
 *
 * This function locks given context, removes switch, unlock context and
 * return.
 */
int ast_context_remove_switch2(struct ast_context *con, const char *sw, const char *data, const char *registrar)
{
	struct ast_sw *i, *pi = NULL;

	if (ast_mutex_lock(&con->lock)) return -1;

	/* walk switchs */
	i = con->alts;
	while (i) {
		/* find our switch */
		if (!strcmp(i->name, sw) && !strcmp(i->data, data) && 
			(!registrar || !strcmp(i->registrar, registrar))) {
			/* remove from list */
			if (pi)
				pi->next = i->next;
			else
				con->alts = i->next;
			/* free switch and return */
			free(i);
			ast_mutex_unlock(&con->lock);
			return 0;
		}
		pi = i;
		i = i->next;
	}

	/* we can't find the right switch */
	ast_mutex_unlock(&con->lock);
	return -1;
}

/*
 * This functions lock contexts list, search for the right context,
 * call ast_context_remove_extension2, unlock contexts list and return.
 * In this function we are using
 */
int ast_context_remove_extension(const char *context, const char *extension, int priority, const char *registrar)
{
	struct ast_context *c;

	if (ast_lock_contexts()) return -1;

	/* walk contexts ... */
	c = ast_walk_contexts(NULL);
	while (c) {
		/* ... search for the right one ... */
		if (!strcmp(ast_get_context_name(c), context)) {
			/* ... remove extension ... */
			int ret = ast_context_remove_extension2(c, extension, priority,
				registrar);
			/* ... unlock contexts list and return */
			ast_unlock_contexts();
			return ret;
		}
		c = ast_walk_contexts(c);
	}

	/* we can't find the right context */
	ast_unlock_contexts();
	return -1;
}

/*
 * When do you want to call this function, make sure that &conlock is locked,
 * because some process can handle with your *con context before you lock
 * it.
 *
 * This functionc locks given context, search for the right extension and
 * fires out all peer in this extensions with given priority. If priority
 * is set to 0, all peers are removed. After that, unlock context and
 * return.
 */
int ast_context_remove_extension2(struct ast_context *con, const char *extension, int priority, const char *registrar)
{
	struct ast_exten *exten, *prev_exten = NULL;

	if (ast_mutex_lock(&con->lock)) return -1;

	/* go through all extensions in context and search the right one ... */
	exten = con->root;
	while (exten) {

		/* look for right extension */
		if (!strcmp(exten->exten, extension) &&
			(!registrar || !strcmp(exten->registrar, registrar))) {
			struct ast_exten *peer;

			/* should we free all peers in this extension? (priority == 0)? */
			if (priority == 0) {
				/* remove this extension from context list */
				if (prev_exten)
					prev_exten->next = exten->next;
				else
					con->root = exten->next;

				/* fire out all peers */
				peer = exten; 
				while (peer) {
					exten = peer->peer;
					
					if (!peer->priority==PRIORITY_HINT) 
					    ast_remove_hint(peer);

					peer->datad(peer->data);
					free(peer);

					peer = exten;
				}

				ast_mutex_unlock(&con->lock);
				return 0;
			} else {
				/* remove only extension with exten->priority == priority */
				struct ast_exten *previous_peer = NULL;

				peer = exten;
				while (peer) {
					/* is this our extension? */
					if (peer->priority == priority &&
						(!registrar || !strcmp(peer->registrar, registrar) )) {
						/* we are first priority extension? */
						if (!previous_peer) {
							/* exists previous extension here? */
							if (prev_exten) {
								/* yes, so we must change next pointer in
								 * previous connection to next peer
								 */
								if (peer->peer) {
									prev_exten->next = peer->peer;
									peer->peer->next = exten->next;
								} else
									prev_exten->next = exten->next;
							} else {
								/* no previous extension, we are first
								 * extension, so change con->root ...
								 */
								if (peer->peer)
									con->root = peer->peer;
								else
									con->root = exten->next; 
							}
						} else {
							/* we are not first priority in extension */
							previous_peer->peer = peer->peer;
						}

						/* now, free whole priority extension */
						if (peer->priority==PRIORITY_HINT)
						    ast_remove_hint(peer);
						peer->datad(peer->data);
						free(peer);

						ast_mutex_unlock(&con->lock);
						return 0;
					} else {
						/* this is not right extension, skip to next peer */
						previous_peer = peer;
						peer = peer->peer;
					}
				}

				ast_mutex_unlock(&con->lock);
				return -1;
			}
		}

		prev_exten = exten;
		exten = exten->next;
	}

	/* we can't find right extension */
	ast_mutex_unlock(&con->lock);
	return -1;
}


int ast_register_application(const char *app, int (*execute)(struct ast_channel *, void *), const char *synopsis, const char *description)
{
	struct ast_app *tmp, *prev, *cur;
	char tmps[80];
	int length;
	length = sizeof(struct ast_app);
	length += strlen(app) + 1;
	if (ast_mutex_lock(&applock)) {
		ast_log(LOG_ERROR, "Unable to lock application list\n");
		return -1;
	}
	tmp = apps;
	while(tmp) {
		if (!strcasecmp(app, tmp->name)) {
			ast_log(LOG_WARNING, "Already have an application '%s'\n", app);
			ast_mutex_unlock(&applock);
			return -1;
		}
		tmp = tmp->next;
	}
	tmp = malloc(length);
	if (tmp) {
		memset(tmp, 0, length);
		strcpy(tmp->name, app);
		tmp->execute = execute;
		tmp->synopsis = synopsis;
		tmp->description = description;
		/* Store in alphabetical order */
		cur = apps;
		prev = NULL;
		while(cur) {
			if (strcasecmp(tmp->name, cur->name) < 0)
				break;
			prev = cur;
			cur = cur->next;
		}
		if (prev) {
			tmp->next = prev->next;
			prev->next = tmp;
		} else {
			tmp->next = apps;
			apps = tmp;
		}
	} else {
		ast_log(LOG_ERROR, "Out of memory\n");
		ast_mutex_unlock(&applock);
		return -1;
	}
	if (option_verbose > 1)
		ast_verbose( VERBOSE_PREFIX_2 "Registered application '%s'\n", term_color(tmps, tmp->name, COLOR_BRCYAN, 0, sizeof(tmps)));
	ast_mutex_unlock(&applock);
	return 0;
}

int ast_register_switch(struct ast_switch *sw)
{
	struct ast_switch *tmp, *prev=NULL;
	if (ast_mutex_lock(&switchlock)) {
		ast_log(LOG_ERROR, "Unable to lock switch lock\n");
		return -1;
	}
	tmp = switches;
	while(tmp) {
		if (!strcasecmp(tmp->name, sw->name))
			break;
		prev = tmp;
		tmp = tmp->next;
	}
	if (tmp) {	
		ast_mutex_unlock(&switchlock);
		ast_log(LOG_WARNING, "Switch '%s' already found\n", sw->name);
		return -1;
	}
	sw->next = NULL;
	if (prev) 
		prev->next = sw;
	else
		switches = sw;
	ast_mutex_unlock(&switchlock);
	return 0;
}

void ast_unregister_switch(struct ast_switch *sw)
{
	struct ast_switch *tmp, *prev=NULL;
	if (ast_mutex_lock(&switchlock)) {
		ast_log(LOG_ERROR, "Unable to lock switch lock\n");
		return;
	}
	tmp = switches;
	while(tmp) {
		if (tmp == sw) {
			if (prev)
				prev->next = tmp->next;
			else
				switches = tmp->next;
			tmp->next = NULL;
			break;			
		}
		prev = tmp;
		tmp = tmp->next;
	}
	ast_mutex_unlock(&switchlock);
}

/*
 * Help for CLI commands ...
 */
static char show_application_help[] = 
"Usage: show application <application> [<application> [<application> [...]]]\n"
"       Describes a particular application.\n";

static char show_functions_help[] =
"Usage: show functions\n"
"       List builtin functions accessable as $(function args)\n";

static char show_function_help[] =
"Usage: show function <function>\n"
"       Describe a particular dialplan function.\n";

static char show_applications_help[] =
"Usage: show applications [{like|describing} <text>]\n"
"       List applications which are currently available.\n"
"       If 'like', <text> will be a substring of the app name\n"
"       If 'describing', <text> will be a substring of the description\n";

static char show_dialplan_help[] =
"Usage: show dialplan [exten@][context]\n"
"       Show dialplan\n";

static char show_switches_help[] =