Someone

static char *builtin_function_cdr_read(struct ast_channel *chan, char *cmd, char *data, char *buf, size_t len)
{
        char *ret;
        char *mydata;
        int argc;
        char *argv[2];
        int recursive = 0;

        if (!data || ast_strlen_zero(data))
                return NULL;

        if (!chan->cdr)
                return NULL;

        mydata = ast_strdupa(data);
        argc = ast_separate_app_args(mydata, '|', argv, sizeof(argv) / sizeof(argv[0]));

        /* check for a trailing flags argument */
        if ((argc > 1) && !strchr(argv[argc-1], '=')) {
                argc--;
                if (strchr(argv[argc], 'r'))
                        recursive = 1;
        }

        ast_cdr_getvar(chan->cdr, argv[0], &ret, buf, len, recursive);

        return ret;
}