use Fcntl ':mode';

my %TYPE = (S_IFDIR,'d',S_IFCHR,'c',S_IFBLK,'b',S_IFREG,'-',S_IFLNK,'l',
            S_IFSOCK,'s');

sub o
{
    my ($mode, $xr, $xid) = @_;
    (($mode & ($xr | $xid)) == ($xr | $xid)) ? 's'
        : ($mode & $xr) ? 'x' : ($mode & $xid) ? 'S' : '-';
}

sub strmode
{
    my ($mode) = @_;
    ($TYPE{$mode & S_IFMT} || '?')
        . (($mode & S_IRUSR) ? 'r' : '-')
        . (($mode & S_IWUSR) ? 'w' : '-')
        . o($mode, S_IXUSR, S_ISUID)
        . (($mode & S_IRGRP) ? 'r' : '-')
        . (($mode & S_IWGRP) ? 'w' : '-')
        . o($mode, S_IXGRP, S_ISGID)
        . (($mode & S_IROTH) ? 'r' : '-')
        . (($mode & S_IWOTH) ? 'w' : '-')
        . o($mode, S_IXOTH, S_ISVTX)
}