pbx.c

		AST_LIST_TRAVERSE(places[i], variables, entries) {
			if (strcasecmp(ast_var_name(variables), var)==0) {
				s = ast_var_value(variables);
				break;
			}
		}
		if (places[i] == &globals)
			ast_mutex_unlock(&globalslock);
	}
	if (s == &not_found || s == NULL)
		*ret = NULL;
	else {
		if (s != workspace)
			ast_copy_string(workspace, s, workspacelen);
		*ret = workspace;
		if (need_substring)
			*ret = substring(*ret, offset, length, workspace, workspacelen);
	}
}

/*! \brief CLI function to show installed custom functions 
    \addtogroup CLI_functions
 */
static int handle_show_functions(int fd, int argc, char *argv[])
{
	struct ast_custom_function *acf;
	int count_acf = 0;
	int print_acf = 0;
	int like = 0;

	if (argc == 4 && (!strcmp(argv[2], "like")) ) {
		like = 1;
	} else if (argc != 2) {
		return RESULT_SHOWUSAGE;
	}

	ast_cli(fd, "%s Custom Functions:\n--------------------------------------------------------------------------------\n", like ? "Matching" : "Installed");
	
	for (acf = acf_root ; acf; acf = acf->next) {
		print_acf = 0;
		if (like) {
			if (strstr(acf->name, argv[3])) {
				print_acf = 1;
				count_acf++;
			}
		} else {
			print_acf = 1;
			count_acf++;
		} 

		if (print_acf) {
			ast_cli(fd, "%-20.20s  %-35.35s  %s\n", acf->name, acf->syntax, acf->synopsis);
		}
	}

	ast_cli(fd, "%d %scustom functions installed.\n", count_acf, like ? "matching " : "");

	return 0;
}

static int handle_show_function(int fd, int argc, char *argv[])
{
	struct ast_custom_function *acf;
	/* Maximum number of characters added by terminal coloring is 22 */
	char infotitle[64 + AST_MAX_APP + 22], syntitle[40], destitle[40];
	char info[64 + AST_MAX_APP], *synopsis = NULL, *description = NULL;
	char stxtitle[40], *syntax = NULL;
	int synopsis_size, description_size, syntax_size;

	if (argc < 3) return RESULT_SHOWUSAGE;

	if (!(acf = ast_custom_function_find(argv[2]))) {
		ast_cli(fd, "No function by that name registered.\n");
		return RESULT_FAILURE;

	}

	if (acf->synopsis)
		synopsis_size = strlen(acf->synopsis) + 23;
	else
		synopsis_size = strlen("Not available") + 23;
	synopsis = alloca(synopsis_size);
	
	if (acf->desc)
		description_size = strlen(acf->desc) + 23;
	else
		description_size = strlen("Not available") + 23;
	description = alloca(description_size);

	if (acf->syntax)
		syntax_size = strlen(acf->syntax) + 23;
	else
		syntax_size = strlen("Not available") + 23;
	syntax = alloca(syntax_size);

	snprintf(info, 64 + AST_MAX_APP, "\n  -= Info about function '%s' =- \n\n", acf->name);
	term_color(infotitle, info, COLOR_MAGENTA, 0, 64 + AST_MAX_APP + 22);
	term_color(stxtitle, "[Syntax]\n", COLOR_MAGENTA, 0, 40);
	term_color(syntitle, "[Synopsis]\n", COLOR_MAGENTA, 0, 40);
	term_color(destitle, "[Description]\n", COLOR_MAGENTA, 0, 40);
	term_color(syntax,
		   acf->syntax ? acf->syntax : "Not available",
		   COLOR_CYAN, 0, syntax_size);
	term_color(synopsis,
		   acf->synopsis ? acf->synopsis : "Not available",
		   COLOR_CYAN, 0, synopsis_size);
	term_color(description,
		   acf->desc ? acf->desc : "Not available",
		   COLOR_CYAN, 0, description_size);
	
	ast_cli(fd,"%s%s%s\n\n%s%s\n\n%s%s\n", infotitle, stxtitle, syntax, syntitle, synopsis, destitle, description);

	return RESULT_SUCCESS;
}

static char *complete_show_function(const char *line, const char *word, int pos, int state)
{
	struct ast_custom_function *acf;
	char *ret = NULL;
	int which = 0;
	int wordlen = strlen(word);

	/* try to lock functions list ... */
	if (ast_mutex_lock(&acflock)) {
		ast_log(LOG_ERROR, "Unable to lock function list\n");
		return NULL;
	}

	/* case-insensitive for convenience in this 'complete' function */
 	for (acf = acf_root; acf && !ret; acf = acf->next) {
 		if (!strncasecmp(word, acf->name, wordlen) && ++which > state)
 			ret = strdup(acf->name);
	}

	ast_mutex_unlock(&acflock);

	return ret; 
}

struct ast_custom_function* ast_custom_function_find(const char *name) 
{
	struct ast_custom_function *acfptr;

	/* try to lock functions list ... */
	if (ast_mutex_lock(&acflock)) {
		ast_log(LOG_ERROR, "Unable to lock function list\n");
		return NULL;
	}

	for (acfptr = acf_root; acfptr; acfptr = acfptr->next) {
		if (!strcmp(name, acfptr->name))
			break;
	}

	ast_mutex_unlock(&acflock);
	
	return acfptr;
}

int ast_custom_function_unregister(struct ast_custom_function *acf) 
{
	struct ast_custom_function *acfptr, *lastacf = NULL;
	int res = -1;

	if (!acf)
		return -1;

	/* try to lock functions list ... */
	if (ast_mutex_lock(&acflock)) {
		ast_log(LOG_ERROR, "Unable to lock function list\n");
		return -1;
	}

	for (acfptr = acf_root; acfptr; acfptr = acfptr->next) {
		if (acfptr == acf) {
			if (lastacf) {
				lastacf->next = acf->next;
			} else {
				acf_root = acf->next;
			}
			res = 0;
			break;
		}
		lastacf = acfptr;
	}

	ast_mutex_unlock(&acflock);

	if (!res && (option_verbose > 1))
		ast_verbose(VERBOSE_PREFIX_2 "Unregistered custom function %s\n", acf->name);

	return res;
}

int ast_custom_function_register(struct ast_custom_function *acf) 
{
	struct ast_custom_function *cur, *last = NULL;
	int found = 0;

	if (!acf)
		return -1;

	/* try to lock functions list ... */
	if (ast_mutex_lock(&acflock)) {
		ast_log(LOG_ERROR, "Unable to lock function list. Failed registering function %s\n", acf->name);
		return -1;
	}

	if (ast_custom_function_find(acf->name)) {
		ast_log(LOG_ERROR, "Function %s already registered.\n", acf->name);
		ast_mutex_unlock(&acflock);
		return -1;
	}

	for (cur = acf_root; cur; cur = cur->next) {
		if (strcmp(acf->name, cur->name) < 0) {
			found = 1;
			if (last) {
				acf->next = cur;
				last->next = acf;
			} else {
				acf->next = acf_root;
				acf_root = acf;
			}
			break;
		}
		last = cur;
	}

	/* Wasn't before anything else, put it at the end */
	if (!found) {
		if (last)
			last->next = acf;
		else
			acf_root = acf;
		acf->next = NULL;
	}

	ast_mutex_unlock(&acflock);

	if (option_verbose > 1)
		ast_verbose(VERBOSE_PREFIX_2 "Registered custom function %s\n", acf->name);

	return 0;
}

int ast_func_read(struct ast_channel *chan, char *function, char *workspace, size_t len)
{
	char *args = NULL, *p;
	struct ast_custom_function *acfptr;

	if ((args = strchr(function, '('))) {
		*args++ = '\0';
		if ((p = strrchr(args, ')')))
			*p = '\0';
		else
			ast_log(LOG_WARNING, "Can't find trailing parenthesis?\n");
	} else {
		ast_log(LOG_WARNING, "Function doesn't contain parentheses.  Assuming null argument.\n");
	}

	if ((acfptr = ast_custom_function_find(function))) {
		/* run the custom function */
		if (acfptr->read)
			return acfptr->read(chan, function, args, workspace, len);
		else
			ast_log(LOG_ERROR, "Function %s cannot be read\n", function);
	} else {
		ast_log(LOG_ERROR, "Function %s not registered\n", function);
	}

	return -1;
}

int ast_func_write(struct ast_channel *chan, char *function, const char *value)
{
	char *args = NULL, *p;
	struct ast_custom_function *acfptr;

	if ((args = strchr(function, '('))) {
		*args++ = '\0';
		if ((p = strrchr(args, ')')))
			*p = '\0';
		else
			ast_log(LOG_WARNING, "Can't find trailing parenthesis?\n");
	} else {
		ast_log(LOG_WARNING, "Function doesn't contain parentheses.  Assuming null argument.\n");
	}

	if ((acfptr = ast_custom_function_find(function))) {
		/* run the custom function */
		if (acfptr->write)
			return acfptr->write(chan, function, args, value);
		else
			ast_log(LOG_ERROR, "Function %s is read-only, it cannot be written to\n", function);
	} else {
		ast_log(LOG_ERROR, "Function %s not registered\n", function);
	}

	return -1;
}

static void pbx_substitute_variables_helper_full(struct ast_channel *c, struct varshead *headp, const char *cp1, char *cp2, int count)
{
	char *cp4;
	const char *tmp, *whereweare;
	int length, offset, offset2, isfunction;
	char *workspace = NULL;
	char *ltmp = NULL, *var = NULL;
	char *nextvar, *nextexp, *nextthing;
	char *vars, *vare;
	int pos, brackets, needsub, len;
	
	/* Substitutes variables into cp2, based on string cp1, and assuming cp2 to be
	   zero-filled */
	whereweare=tmp=cp1;
	while(!ast_strlen_zero(whereweare) && count) {
		/* Assume we're copying the whole remaining string */
		pos = strlen(whereweare);
		nextvar = NULL;
		nextexp = NULL;
		nextthing = strchr(whereweare, '$');
		if (nextthing) {
			switch(nextthing[1]) {
			case '{':
				nextvar = nextthing;
				pos = nextvar - whereweare;
				break;
			case '[':
				nextexp = nextthing;
				pos = nextexp - whereweare;
				break;
			}
		}

		if (pos) {
			/* Can't copy more than 'count' bytes */
			if (pos > count)
				pos = count;
			
			/* Copy that many bytes */
			memcpy(cp2, whereweare, pos);
			
			count -= pos;
			cp2 += pos;
			whereweare += pos;
		}
		
		if (nextvar) {
			/* We have a variable.  Find the start and end, and determine
			   if we are going to have to recursively call ourselves on the
			   contents */
			vars = vare = nextvar + 2;
			brackets = 1;
			needsub = 0;

			/* Find the end of it */
			while(brackets && *vare) {
				if ((vare[0] == '$') && (vare[1] == '{')) {
					needsub++;
					brackets++;
				} else if (vare[0] == '}') {
					brackets--;
				} else if ((vare[0] == '$') && (vare[1] == '['))
					needsub++;
				vare++;
			}
			if (brackets)
				ast_log(LOG_NOTICE, "Error in extension logic (missing '}')\n");
			len = vare - vars - 1;

			/* Skip totally over variable string */
			whereweare += (len + 3);

			if (!var)
				var = alloca(VAR_BUF_SIZE);

			/* Store variable name (and truncate) */
			ast_copy_string(var, vars, len + 1);

			/* Substitute if necessary */
			if (needsub) {
				if (!ltmp)
					ltmp = alloca(VAR_BUF_SIZE);

				memset(ltmp, 0, VAR_BUF_SIZE);
				pbx_substitute_variables_helper_full(c, headp, var, ltmp, VAR_BUF_SIZE - 1);
				vars = ltmp;
			} else {
				vars = var;
			}

			if (!workspace)
				workspace = alloca(VAR_BUF_SIZE);

			workspace[0] = '\0';

			parse_variable_name(vars, &offset, &offset2, &isfunction);
			if (isfunction) {
				/* Evaluate function */
				cp4 = ast_func_read(c, vars, workspace, VAR_BUF_SIZE) ? NULL : workspace;

				ast_log(LOG_DEBUG, "Function result is '%s'\n", cp4 ? cp4 : "(null)");
			} else {
				/* Retrieve variable value */
				pbx_retrieve_variable(c, vars, &cp4, workspace, VAR_BUF_SIZE, headp);
			}
			if (cp4) {
				cp4 = substring(cp4, offset, offset2, workspace, VAR_BUF_SIZE);

				length = strlen(cp4);
				if (length > count)
					length = count;
				memcpy(cp2, cp4, length);
				count -= length;
				cp2 += length;
			}
		} else if (nextexp) {
			/* We have an expression.  Find the start and end, and determine
			   if we are going to have to recursively call ourselves on the
			   contents */
			vars = vare = nextexp + 2;
			brackets = 1;
			needsub = 0;

			/* Find the end of it */
			while(brackets && *vare) {
				if ((vare[0] == '$') && (vare[1] == '[')) {
					needsub++;
					brackets++;
					vare++;
				} else if (vare[0] == '[') {
					brackets++;
				} else if (vare[0] == ']') {
					brackets--;
				} else if ((vare[0] == '$') && (vare[1] == '{')) {
					needsub++;
					vare++;
				}
				vare++;
			}
			if (brackets)
				ast_log(LOG_NOTICE, "Error in extension logic (missing ']')\n");
			len = vare - vars - 1;
			
			/* Skip totally over expression */
			whereweare += (len + 3);
			
			if (!var)
				var = alloca(VAR_BUF_SIZE);

			/* Store variable name (and truncate) */
			ast_copy_string(var, vars, len + 1);
			
			/* Substitute if necessary */
			if (needsub) {
				if (!ltmp)
					ltmp = alloca(VAR_BUF_SIZE);

				memset(ltmp, 0, VAR_BUF_SIZE);
				pbx_substitute_variables_helper_full(c, headp, var, ltmp, VAR_BUF_SIZE - 1);
				vars = ltmp;
			} else {
				vars = var;
			}

			length = ast_expr(vars, cp2, count);

			if (length) {
				ast_log(LOG_DEBUG, "Expression result is '%s'\n", cp2);
				count -= length;
				cp2 += length;
			}
		} else
			break;
	}
}

void pbx_substitute_variables_helper(struct ast_channel *c, const char *cp1, char *cp2, int count)
{
	pbx_substitute_variables_helper_full(c, (c) ? &c->varshead : NULL, cp1, cp2, count);
}

void pbx_substitute_variables_varshead(struct varshead *headp, const char *cp1, char *cp2, int count)
{
	pbx_substitute_variables_helper_full(NULL, headp, cp1, cp2, count);
}

static void pbx_substitute_variables(char *passdata, int datalen, struct ast_channel *c, struct ast_exten *e)
{
	memset(passdata, 0, datalen);
		
	/* No variables or expressions in e->data, so why scan it? */
	if (!strchr(e->data, '$') && !strstr(e->data,"${") && !strstr(e->data,"$[") && !strstr(e->data,"$(")) {
		ast_copy_string(passdata, e->data, datalen);
		return;
	}
	
	pbx_substitute_variables_helper(c, e->data, passdata, datalen - 1);
}		                                                

static int pbx_extension_helper(struct ast_channel *c, struct ast_context *con, const char *context, const char *exten, int priority, const char *label, const char *callerid, int action) 
{
	struct ast_exten *e;
	struct ast_app *app;
	struct ast_switch *sw;
	char *data;
	const char *foundcontext=NULL;
	int res;
	int status = 0;
	char *incstack[AST_PBX_MAX_STACK];
	char passdata[EXT_DATA_SIZE];
	int stacklen = 0;
	char tmp[80];
	char tmp2[80];
	char tmp3[EXT_DATA_SIZE];
	char atmp[80];
	char atmp2[EXT_DATA_SIZE+100];

	if (ast_mutex_lock(&conlock)) {
		ast_log(LOG_WARNING, "Unable to obtain lock\n");
		if ((action == HELPER_EXISTS) || (action == HELPER_CANMATCH) || (action == HELPER_MATCHMORE))
			return 0;
		else
			return -1;
	}
	e = pbx_find_extension(c, con, context, exten, priority, label, callerid, action, incstack, &stacklen, &status, &sw, &data, &foundcontext);
	if (e) {
		switch(action) {
		case HELPER_CANMATCH:
			ast_mutex_unlock(&conlock);
			return -1;
		case HELPER_EXISTS:
			ast_mutex_unlock(&conlock);
			return -1;
		case HELPER_FINDLABEL:
			res = e->priority;
			ast_mutex_unlock(&conlock);
			return res;
		case HELPER_MATCHMORE:
			ast_mutex_unlock(&conlock);
			return -1;
		case HELPER_SPAWN:
			app = pbx_findapp(e->app);
			ast_mutex_unlock(&conlock);
			if (app) {
				if (c->context != context)
					ast_copy_string(c->context, context, sizeof(c->context));
				if (c->exten != exten)
					ast_copy_string(c->exten, exten, sizeof(c->exten));
				c->priority = priority;
				pbx_substitute_variables(passdata, sizeof(passdata), c, e);
				if (option_debug) {
						ast_log(LOG_DEBUG, "Launching '%s'\n", app->name);
						snprintf(atmp, 80, "STACK-%s-%s-%d", context, exten, priority);
						snprintf(atmp2, EXT_DATA_SIZE+100, "%s(\"%s\", \"%s\") %s", app->name, c->name, passdata, "in new stack");
						pbx_builtin_setvar_helper(c, atmp, atmp2);
				}
				if (option_verbose > 2)
						ast_verbose( VERBOSE_PREFIX_3 "Executing %s(\"%s\", \"%s\") %s\n", 
								term_color(tmp, app->name, COLOR_BRCYAN, 0, sizeof(tmp)),
								term_color(tmp2, c->name, COLOR_BRMAGENTA, 0, sizeof(tmp2)),
								term_color(tmp3, passdata, COLOR_BRMAGENTA, 0, sizeof(tmp3)),
								"in new stack");
				manager_event(EVENT_FLAG_CALL, "Newexten", 
					"Channel: %s\r\n"
					"Context: %s\r\n"
					"Extension: %s\r\n"
					"Priority: %d\r\n"
					"Application: %s\r\n"
					"AppData: %s\r\n"
					"Uniqueid: %s\r\n",
					c->name, c->context, c->exten, c->priority, app->name, passdata, c->uniqueid);
				res = pbx_exec(c, app, passdata);
				return res;
			} else {
				ast_log(LOG_WARNING, "No application '%s' for extension (%s, %s, %d)\n", e->app, context, exten, priority);
				return -1;
			}
		default:
			ast_log(LOG_WARNING, "Huh (%d)?\n", action);
			return -1;
		}
	} else if (sw) {
		switch(action) {
		case HELPER_CANMATCH:
			ast_mutex_unlock(&conlock);
			return -1;
		case HELPER_EXISTS:
			ast_mutex_unlock(&conlock);
			return -1;
		case HELPER_MATCHMORE:
			ast_mutex_unlock(&conlock);
			return -1;
		case HELPER_FINDLABEL:
			ast_mutex_unlock(&conlock);
			return -1;
		case HELPER_SPAWN:
			ast_mutex_unlock(&conlock);
			if (sw->exec)
				res = sw->exec(c, foundcontext ? foundcontext : context, exten, priority, callerid, data);
			else {
				ast_log(LOG_WARNING, "No execution engine for switch %s\n", sw->name);
				res = -1;
			}
			return res;
		default:
			ast_log(LOG_WARNING, "Huh (%d)?\n", action);
			return -1;
		}
	} else {
		ast_mutex_unlock(&conlock);
		switch(status) {
		case STATUS_NO_CONTEXT:
			if ((action != HELPER_EXISTS) && (action != HELPER_MATCHMORE))
				ast_log(LOG_NOTICE, "Cannot find extension context '%s'\n", context);
			break;
		case STATUS_NO_EXTENSION:
			if ((action != HELPER_EXISTS) && (action !=  HELPER_CANMATCH) && (action != HELPER_MATCHMORE))
				ast_log(LOG_NOTICE, "Cannot find extension '%s' in context '%s'\n", exten, context);
			break;
		case STATUS_NO_PRIORITY:
			if ((action != HELPER_EXISTS) && (action !=  HELPER_CANMATCH) && (action != HELPER_MATCHMORE))
				ast_log(LOG_NOTICE, "No such priority %d in extension '%s' in context '%s'\n", priority, exten, context);
			break;
		case STATUS_NO_LABEL:
			if (context)
				ast_log(LOG_NOTICE, "No such label '%s' in extension '%s' in context '%s'\n", label, exten, context);
			break;
		default:
			ast_log(LOG_DEBUG, "Shouldn't happen!\n");
		}
		
		if ((action != HELPER_EXISTS) && (action != HELPER_CANMATCH) && (action != HELPER_MATCHMORE))
			return -1;
		else
			return 0;
	}

}

/*! \brief  ast_hint_extension: Find hint for given extension in context */
static struct ast_exten *ast_hint_extension(struct ast_channel *c, const char *context, const char *exten)
{
	struct ast_exten *e;
	struct ast_switch *sw;
	char *data;
	const char *foundcontext = NULL;
	int status = 0;
	char *incstack[AST_PBX_MAX_STACK];
	int stacklen = 0;

	if (ast_mutex_lock(&conlock)) {
		ast_log(LOG_WARNING, "Unable to obtain lock\n");
		return NULL;
	}
	e = pbx_find_extension(c, NULL, context, exten, PRIORITY_HINT, NULL, "", HELPER_EXISTS, incstack, &stacklen, &status, &sw, &data, &foundcontext);
	ast_mutex_unlock(&conlock);	
	return e;
}

/*! \brief  ast_extensions_state2: Check state of extension by using hints */
static int ast_extension_state2(struct ast_exten *e)
{
	char hint[AST_MAX_EXTENSION];
	char *cur, *rest;
	int allunavailable = 1, allbusy = 1, allfree = 1;
	int busy = 0, inuse = 0, ring = 0;

	if (!e)
		return -1;

	ast_copy_string(hint, ast_get_extension_app(e), sizeof(hint));

	rest = hint;	/* One or more devices separated with a & character */
	while ( (cur = strsep(&rest, "&")) ) {
		int res = ast_device_state(cur);
		switch (res) {
		case AST_DEVICE_NOT_INUSE:
			allunavailable = 0;
			allbusy = 0;
			break;
		case AST_DEVICE_INUSE:
			inuse = 1;
			allunavailable = 0;
			allfree = 0;
			break;
		case AST_DEVICE_RINGING:
			ring = 1;
			allunavailable = 0;
			allfree = 0;
			break;
		case AST_DEVICE_BUSY:
			allunavailable = 0;
			allfree = 0;
			busy = 1;
			break;
		case AST_DEVICE_UNAVAILABLE:
		case AST_DEVICE_INVALID:
			allbusy = 0;
			allfree = 0;
			break;
		default:
			allunavailable = 0;
			allbusy = 0;
			allfree = 0;
		}
	}

	if (!inuse && ring)
		return AST_EXTENSION_RINGING;
	if (inuse && ring)
		return (AST_EXTENSION_INUSE | AST_EXTENSION_RINGING);
	if (inuse)
		return AST_EXTENSION_INUSE;
	if (allfree)
		return AST_EXTENSION_NOT_INUSE;
	if (allbusy)		
		return AST_EXTENSION_BUSY;
	if (allunavailable)
		return AST_EXTENSION_UNAVAILABLE;
	if (busy) 
		return AST_EXTENSION_INUSE;
	
	return AST_EXTENSION_NOT_INUSE;
}

/*! \brief  ast_extension_state2str: Return extension_state as string */
const char *ast_extension_state2str(int extension_state)
{
	int i;

	for (i = 0; (i < (sizeof(extension_states) / sizeof(extension_states[0]))); i++) {
		if (extension_states[i].extension_state == extension_state)
			return extension_states[i].text;
	}
	return "Unknown";	
}

/*! \brief  ast_extension_state: Check extension state for an extension by using hint */
int ast_extension_state(struct ast_channel *c, const char *context, const char *exten)
{
	struct ast_exten *e;

	e = ast_hint_extension(c, context, exten);	/* Do we have a hint for this extension ? */ 
	if (!e) 
		return -1;				/* No hint, return -1 */

	return ast_extension_state2(e);    		/* Check all devices in the hint */
}

void ast_hint_state_changed(const char *device)
{
	struct ast_hint *hint;
	struct ast_state_cb *cblist;
	char buf[AST_MAX_EXTENSION];
	char *parse;
	char *cur;
	int state;

	AST_LIST_LOCK(&hints);

	AST_LIST_TRAVERSE(&hints, hint, list) {
		ast_copy_string(buf, ast_get_extension_app(hint->exten), sizeof(buf));
		parse = buf;
		for (cur = strsep(&parse, "&"); cur; cur = strsep(&parse, "&")) {
			if (strcasecmp(cur, device))
				continue;

			/* Get device state for this hint */
			state = ast_extension_state2(hint->exten);
			
			if ((state == -1) || (state == hint->laststate))
				continue;

			/* Device state changed since last check - notify the watchers */
			
			/* For general callbacks */
			for (cblist = statecbs; cblist; cblist = cblist->next)
				cblist->callback(hint->exten->parent->name, hint->exten->exten, state, cblist->data);
			
			/* For extension callbacks */
			for (cblist = hint->callbacks; cblist; cblist = cblist->next)
				cblist->callback(hint->exten->parent->name, hint->exten->exten, state, cblist->data);
			
			hint->laststate = state;
			break;
		}
	}

	AST_LIST_UNLOCK(&hints);
}
			
/*! \brief  ast_extension_state_add: Add watcher for extension states */
int ast_extension_state_add(const char *context, const char *exten, 
			    ast_state_cb_type callback, void *data)
{
	struct ast_hint *hint;
	struct ast_state_cb *cblist;
	struct ast_exten *e;

	/* If there's no context and extension:  add callback to statecbs list */
	if (!context && !exten) {
		AST_LIST_LOCK(&hints);

		for (cblist = statecbs; cblist; cblist = cblist->next) {
			if (cblist->callback == callback) {
				cblist->data = data;
				AST_LIST_UNLOCK(&hints);
				return 0;
			}
		}
	
		/* Now insert the callback */
		if (!(cblist = ast_calloc(1, sizeof(*cblist)))) {
			AST_LIST_UNLOCK(&hints);	
			return -1;
		}
		cblist->id = 0;
		cblist->callback = callback;
		cblist->data = data;
	
		cblist->next = statecbs;
		statecbs = cblist;

		AST_LIST_UNLOCK(&hints);
		return 0;
	}

	if (!context || !exten)
		return -1;

	/* This callback type is for only one hint, so get the hint */
	e = ast_hint_extension(NULL, context, exten);    
	if (!e) {
		return -1;
	}

	/* Find the hint in the list of hints */
	AST_LIST_LOCK(&hints);
	
	AST_LIST_TRAVERSE(&hints, hint, list) {
		if (hint->exten == e)
			break;	    
	}

	if (!hint) {
		/* We have no hint, sorry */
		AST_LIST_UNLOCK(&hints);
		return -1;
	}

	/* Now insert the callback in the callback list  */
	if (!(cblist = ast_calloc(1, sizeof(*cblist)))) {
		AST_LIST_UNLOCK(&hints);
		return -1;
	}
	cblist->id = stateid++;		/* Unique ID for this callback */
	cblist->callback = callback;	/* Pointer to callback routine */
	cblist->data = data;		/* Data for the callback */

	cblist->next = hint->callbacks;
	hint->callbacks = cblist;

	AST_LIST_UNLOCK(&hints);
	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 *hint;
	struct ast_state_cb *cblist, *cbprev;

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

	AST_LIST_LOCK(&hints);

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

				free(cblist);

	        		AST_LIST_UNLOCK(&hints);
				return 0;
	    		}
	    		cbprev = cblist;
		}

		AST_LIST_UNLOCK(&hints);
		return -1;
	}

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

	AST_LIST_UNLOCK(&hints);
	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 *hint;

	if (!e) 
		return -1;

	AST_LIST_LOCK(&hints);

	/* Search if hint exists, do nothing */
	AST_LIST_TRAVERSE(&hints, hint, list) {
		if (hint->exten == e) {
			AST_LIST_UNLOCK(&hints);
			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;
		}
	}

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

	if (!(hint = ast_calloc(1, sizeof(*hint)))) {
		AST_LIST_UNLOCK(&hints);
		return -1;
	}
	/* Initialize and insert new item at the top */
	hint->exten = e;
	hint->laststate = ast_extension_state2(e);
	AST_LIST_INSERT_HEAD(&hints, hint, list);

	AST_LIST_UNLOCK(&hints);
	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 *hint;
	int res = -1;

	AST_LIST_LOCK(&hints);
	AST_LIST_TRAVERSE(&hints, hint, list) {
		if (hint->exten == oe) {
	    		hint->exten = ne;
			res = 0;
			break;
		}
	}
	AST_LIST_UNLOCK(&hints);

	return res;
}

/*! \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 *hint;
	struct ast_state_cb *cblist, *cbprev;
	int res = -1;

	if (!e) 
		return -1;

	AST_LIST_LOCK(&hints);
	AST_LIST_TRAVERSE_SAFE_BEGIN(&hints, hint, list) {
		if (hint->exten == e) {
			cbprev = NULL;
			cblist = hint->callbacks;
			while (cblist) {
				/* Notify with -1 and remove all callbacks */
				cbprev = cblist;	    
				cblist = cblist->next;