pbx.c

		res = !aswf ? 0 : aswf(chan, context, exten, priority, callerid, datap);
		if (res) {	/* Got a match */
			q->swo = asw;
			q->data = datap;
			q->foundcontext = context;
			/* XXX keep status = STATUS_NO_CONTEXT ? */
			return NULL;
		}
	}
	q->incstack[q->stacklen++] = tmp->name;	/* Setup the stack */
	/* Now try any includes we have in this context */
	for (i = tmp->includes; i; i = i->next) {
		if (include_valid(i)) {
			if ((e = pbx_find_extension(chan, bypass, q, i->rname, exten, priority, label, callerid, action)))
				return e;
			if (q->swo)
				return NULL;
		}
	}
	return NULL;
}

/* Note that it's negative -- that's important later. */
#define DONT_HAVE_LENGTH	0x80000000

/*! \brief extract offset:length from variable name.
 * Returns 1 if there is a offset:length part, which is
 * trimmed off (values go into variables)
 */
static int parse_variable_name(char *var, int *offset, int *length, int *isfunc)
{
	int parens=0;

	*offset = 0;
	*length = DONT_HAVE_LENGTH;
	*isfunc = 0;
	for (; *var; var++) {
		if (*var == '(') {
			(*isfunc)++;
			parens++;
		} else if (*var == ')') {
			parens--;
		} else if (*var == ':' && parens == 0) {
			*var++ = '\0';
			sscanf(var, "%d:%d", offset, length);
			return 1; /* offset:length valid */
		}
	}
	return 0;
}

/*! \brief takes a substring. It is ok to call with value == workspace.
 *
 * offset < 0 means start from the end of the string and set the beginning
 *   to be that many characters back.
 * length is the length of the substring, -1 means unlimited
 * (we take any negative value).
 * Always return a copy in workspace.
 */
static char *substring(const char *value, int offset, int length, char *workspace, size_t workspace_len)
{
	char *ret = workspace;
	int lr;	/* length of the input string after the copy */

	ast_copy_string(workspace, value, workspace_len); /* always make a copy */

	/* Quick check if no need to do anything */
	if (offset == 0 && length < 0)	/* take the whole string */
		return ret;

	lr = strlen(ret); /* compute length after copy, so we never go out of the workspace */

	if (offset < 0)	{	/* translate negative offset into positive ones */
		offset = lr + offset;
		if (offset < 0) /* If the negative offset was greater than the length of the string, just start at the beginning */
			offset = 0;
	}

	/* too large offset result in empty string so we know what to return */
	if (offset >= lr)
		return ret + lr;	/* the final '\0' */

	ret += offset;		/* move to the start position */
	if (length >= 0 && length < lr - offset)	/* truncate if necessary */
		ret[length] = '\0';

	return ret;
}

/*! \brief  pbx_retrieve_variable: Support for Asterisk built-in variables and
      functions in the dialplan
  ---*/
void pbx_retrieve_variable(struct ast_channel *c, const char *var, char **ret, char *workspace, int workspacelen, struct varshead *headp)
{
	const char not_found = '\0';
	char *tmpvar;
	const char *s;	/* the result */
	int offset, length;
	int i, need_substring;
	struct varshead *places[2] = { headp, &globals };	/* list of places where we may look */

	if (c) {
		places[0] = &c->varshead;
	}
	/*
	 * Make a copy of var because parse_variable_name() modifies the string.
	 * Then if called directly, we might need to run substring() on the result;
	 * remember this for later in 'need_substring', 'offset' and 'length'
	 */
	tmpvar = ast_strdupa(var);	/* parse_variable_name modifies the string */
	need_substring = parse_variable_name(tmpvar, &offset, &length, &i /* ignored */);

	/*
	 * Look first into predefined variables, then into variable lists.
	 * Variable 's' points to the result, according to the following rules:
	 * s == &not_found (set at the beginning) means that we did not find a
	 *	matching variable and need to look into more places.
	 * If s != &not_found, s is a valid result string as follows:
	 * s = NULL if the variable does not have a value;
	 *	you typically do this when looking for an unset predefined variable.
	 * s = workspace if the result has been assembled there;
	 *	typically done when the result is built e.g. with an snprintf(),
	 *	so we don't need to do an additional copy.
	 * s != workspace in case we have a string, that needs to be copied
	 *	(the ast_copy_string is done once for all at the end).
	 *	Typically done when the result is already available in some string.
	 */
	s = &not_found;	/* default value */
	if (c) {	/* This group requires a valid channel */
		/* Names with common parts are looked up a piece at a time using strncmp. */
		if (!strncmp(var, "CALL", 4)) {
			if (!strncmp(var + 4, "ING", 3)) {
				if (!strcmp(var + 7, "PRES")) {			/* CALLINGPRES */
					snprintf(workspace, workspacelen, "%d", c->cid.cid_pres);
					s = workspace;
				} else if (!strcmp(var + 7, "ANI2")) {		/* CALLINGANI2 */
					snprintf(workspace, workspacelen, "%d", c->cid.cid_ani2);
					s = workspace;
				} else if (!strcmp(var + 7, "TON")) {		/* CALLINGTON */
					snprintf(workspace, workspacelen, "%d", c->cid.cid_ton);
					s = workspace;
				} else if (!strcmp(var + 7, "TNS")) {		/* CALLINGTNS */
					snprintf(workspace, workspacelen, "%d", c->cid.cid_tns);
					s = workspace;
				}
			}
		} else if (!strcmp(var, "HINT")) {
			s = ast_get_hint(workspace, workspacelen, NULL, 0, c, c->context, c->exten) ? workspace : NULL;
		} else if (!strcmp(var, "HINTNAME")) {
			s = ast_get_hint(NULL, 0, workspace, workspacelen, c, c->context, c->exten) ? workspace : NULL;
		} else if (!strcmp(var, "EXTEN")) {
			s = c->exten;
		} else if (!strcmp(var, "CONTEXT")) {
			s = c->context;
		} else if (!strcmp(var, "PRIORITY")) {
			snprintf(workspace, workspacelen, "%d", c->priority);
			s = workspace;
		} else if (!strcmp(var, "CHANNEL")) {
			s = c->name;
		} else if (!strcmp(var, "UNIQUEID")) {
			s = c->uniqueid;
		} else if (!strcmp(var, "HANGUPCAUSE")) {
			snprintf(workspace, workspacelen, "%d", c->hangupcause);
			s = workspace;
		}
	}
	if (s == &not_found) { /* look for more */
		if (!strcmp(var, "EPOCH")) {
			snprintf(workspace, workspacelen, "%u",(int)time(NULL));
			s = workspace;
		} else if (!strcmp(var, "SYSTEMNAME")) {
			s = ast_config_AST_SYSTEM_NAME;
		}
	}
	/* if not found, look into chanvars or global vars */
	for (i = 0; s == &not_found && i < (sizeof(places) / sizeof(places[0])); i++) {
		struct ast_var_t *variables;
		if (!places[i])
			continue;
		if (places[i] == &globals)
			ast_mutex_lock(&globalslock);
		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 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");

	AST_LIST_LOCK(&acf_root);
	AST_LIST_TRAVERSE(&acf_root, acf, acflist) {
		if (!like || strstr(acf->name, argv[3])) {
			count_acf++;
			ast_cli(fd, "%-20.20s  %-35.35s  %s\n", acf->name, acf->syntax, acf->synopsis);
		}
	}
	AST_LIST_UNLOCK(&acf_root);

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

	return RESULT_SUCCESS;
}

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);

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

	return ret;
}

struct ast_custom_function *ast_custom_function_find(const char *name)
{
	struct ast_custom_function *acf = NULL;

	AST_LIST_LOCK(&acf_root);
	AST_LIST_TRAVERSE(&acf_root, acf, acflist) {
		if (!strcmp(name, acf->name))
			break;
	}
	AST_LIST_UNLOCK(&acf_root);

	return acf;
}

int ast_custom_function_unregister(struct ast_custom_function *acf)
{
	struct ast_custom_function *cur;

	if (!acf)
		return -1;

	AST_LIST_LOCK(&acf_root);
	AST_LIST_TRAVERSE_SAFE_BEGIN(&acf_root, cur, acflist) {
		if (cur == acf) {
			AST_LIST_REMOVE_CURRENT(&acf_root, acflist);
			if (option_verbose > 1)
				ast_verbose(VERBOSE_PREFIX_2 "Unregistered custom function %s\n", acf->name);
			break;
		}
	}
	AST_LIST_TRAVERSE_SAFE_END
	AST_LIST_UNLOCK(&acf_root);

	return acf ? 0 : -1;
}

int ast_custom_function_register(struct ast_custom_function *acf)
{
	struct ast_custom_function *cur;

	if (!acf)
		return -1;

	AST_LIST_LOCK(&acf_root);

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

	/* Store in alphabetical order */
	AST_LIST_TRAVERSE_SAFE_BEGIN(&acf_root, cur, acflist) {
		if (strcasecmp(acf->name, cur->name) < 0) {
			AST_LIST_INSERT_BEFORE_CURRENT(&acf_root, acf, acflist);
			break;
		}
	}
	AST_LIST_TRAVERSE_SAFE_END
	if (!cur)
		AST_LIST_INSERT_TAIL(&acf_root, acf, acflist);

	AST_LIST_UNLOCK(&acf_root);

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

	return 0;
}

/*! \brief return a pointer to the arguments of the function,
 * and terminates the function name with '\\0'
 */
static char *func_args(char *function)
{
	char *args = strchr(function, '(');

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

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

	if (acfptr == NULL)
		ast_log(LOG_ERROR, "Function %s not registered\n", function);
	else if (!acfptr->read)
		ast_log(LOG_ERROR, "Function %s cannot be read\n", function);
	else
		return acfptr->read(chan, function, args, workspace, len);
	return -1;
}

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

	if (acfptr == NULL)
		ast_log(LOG_ERROR, "Function %s not registered\n", function);
	else if (!acfptr->write)
		ast_log(LOG_ERROR, "Function %s cannot be written to\n", function);
	else
		return acfptr->write(chan, function, args, value);

	return -1;
}

static void pbx_substitute_variables_helper_full(struct ast_channel *c, struct varshead *headp, const char *cp1, char *cp2, int count)
{
	/* Substitutes variables into cp2, based on string cp1, and assuming cp2 to be
	   zero-filled */
	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;

	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] == '$') && (vare[1] == '{')) {
					needsub++;
				} else if (vare[0] == '{') {
					brackets++;
				} else if (vare[0] == '}') {
					brackets--;
				} else if ((vare[0] == '$') && (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);
}

/*! \brief The return value depends on the action:
 *
 * E_MATCH, E_CANMATCH, E_MATCHMORE require a real match,
 *	and return 0 on failure, -1 on match;
 * E_FINDLABEL maps the label to a priority, and returns
 *	the priority on success, ... XXX
 * E_SPAWN, spawn an application,
 *	and return 0 on success, -1 on failure.
 */
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, enum ext_match_t action)
{
	struct ast_exten *e;
	struct ast_app *app;
	int res;
	struct pbx_find_info q = { .stacklen = 0 }; /* the rest is reset in pbx_find_extension */
	char passdata[EXT_DATA_SIZE];

	int matching_action = (action == E_MATCH || action == E_CANMATCH || action == E_MATCHMORE);

	ast_mutex_lock(&conlock);
	e = pbx_find_extension(c, con, &q, context, exten, priority, label, callerid, action);
	if (e) {
		if (matching_action) {
			ast_mutex_unlock(&conlock);
			return -1;	/* success, we found it */
		} else if (action == E_FINDLABEL) { /* map the label to a priority */
			res = e->priority;
			ast_mutex_unlock(&conlock);
			return res;	/* the priority we were looking for */
		} else {	/* spawn */
			app = pbx_findapp(e->app);
			ast_mutex_unlock(&conlock);
			if (!app) {
				ast_log(LOG_WARNING, "No application '%s' for extension (%s, %s, %d)\n", e->app, context, exten, priority);
				return -1;
			}
			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) {
				char atmp[80];
				char atmp2[EXT_DATA_SIZE+100];
				ast_log(LOG_DEBUG, "Launching '%s'\n", app->name);
				snprintf(atmp, sizeof(atmp), "STACK-%s-%s-%d", context, exten, priority);
				snprintf(atmp2, sizeof(atmp2), "%s(\"%s\", \"%s\") %s",
					app->name, c->name, passdata, "in new stack");
				pbx_builtin_setvar_helper(c, atmp, atmp2);
			}
			if (option_verbose > 2) {
				char tmp[80], tmp2[80], tmp3[EXT_DATA_SIZE];
				ast_verbose( VERBOSE_PREFIX_3 "Executing [%s@%s:%d] %s(\"%s\", \"%s\") %s\n",
					exten, context, priority,
					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);
			return pbx_exec(c, app, passdata);	/* 0 on success, -1 on failure */
		}
	} else if (q.swo) {	/* not found here, but in another switch */
		ast_mutex_unlock(&conlock);
		if (matching_action)
			return -1;
		else {
			if (!q.swo->exec) {
				ast_log(LOG_WARNING, "No execution engine for switch %s\n", q.swo->name);
				res = -1;
			}
			return q.swo->exec(c, q.foundcontext ? q.foundcontext : context, exten, priority, callerid, q.data);
		}
	} else {	/* not found anywhere, see what happened */
		ast_mutex_unlock(&conlock);
		switch (q.status) {
		case STATUS_NO_CONTEXT:
			if (!matching_action)
				ast_log(LOG_NOTICE, "Cannot find extension context '%s'\n", context);
			break;
		case STATUS_NO_EXTENSION:
			if (!matching_action)
				ast_log(LOG_NOTICE, "Cannot find extension '%s' in context '%s'\n", exten, context);
			break;
		case STATUS_NO_PRIORITY:
			if (!matching_action)
				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");
		}

		return (matching_action) ? 0 : -1;
	}
}

/*! \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 pbx_find_info q = { .stacklen = 0 }; /* the rest is set in pbx_find_context */

	ast_mutex_lock(&conlock);
	e = pbx_find_extension(c, NULL, &q, context, exten, PRIORITY_HINT, NULL, "", E_MATCH);
	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_RINGINUSE:
			inuse = 1;
			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;

	AST_LIST_LOCK(&hints);

	AST_LIST_TRAVERSE(&hints, hint, list) {
		struct ast_state_cb *cblist;
		char buf[AST_MAX_EXTENSION];
		char *parse = buf;
		char *cur;
		int state;

		ast_copy_string(buf, ast_get_extension_app(hint->exten), sizeof(buf));
		while ( (cur = strsep(&parse, "&")) ) {
			if (!strcasecmp(cur, device))
				break;
		}
		if (!cur)
			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;	/* record we saw the change */
	}

	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_state_cb **p_cur = NULL;	/* address of pointer to us */
	int ret = -1;

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

	AST_LIST_LOCK(&hints);

	if (!id) {	/* id == 0 is a callback without extension */
		for (p_cur = &statecbs; *p_cur; p_cur = &(*p_cur)->next) {
	 		if ((*p_cur)->callback == callback)
				break;
		}
	} else { /* callback with extension, find the callback based on ID */
		struct ast_hint *hint;
		AST_LIST_TRAVERSE(&hints, hint, list) {
			for (p_cur = &hint->callbacks; *p_cur; p_cur = &(*p_cur)->next) {
				if ((*p_cur)->id == id)
					break;
			}
			if (*p_cur)	/* found in the inner loop */
				break;
		}
	}
	if (p_cur && *p_cur) {
		struct ast_state_cb *cur = *p_cur;
		*p_cur = cur->next;
		free(cur);
		ret = 0;
	}
	AST_LIST_UNLOCK(&hints);
	return ret;