- unless (@cst = stat( $start ))
- {
- warn "stat($start): $!";
- return '';
- }
- $cwd = '';
- $dotdots = $start;
- do
- {
- $dotdots .= '/..';
- @pst = @cst;
- unless (opendir(PARENT, $dotdots))
- {
- warn "opendir($dotdots): $!";
- return '';
- }
- unless (@cst = stat($dotdots))
- {
- warn "stat($dotdots): $!";
- closedir(PARENT);
- return '';
- }
- if ($pst[0] == $cst[0] && $pst[1] == $cst[1])
- {
- $dir = '';
- }
- else
- {
- do
- {
- unless (defined ($dir = readdir(PARENT)))
- {
- warn "readdir($dotdots): $!";
- closedir(PARENT);
- return '';
- }
- $tst[0] = $pst[0]+1 unless (@tst = lstat("$dotdots/$dir"))
- }
- while ($dir eq '.' || $dir eq '..' || $tst[0] != $pst[0] ||
- $tst[1] != $pst[1]);
- }
- $cwd = "$dir/$cwd";
- closedir(PARENT);
- } while ($dir);
- chop($cwd); # drop the trailing /
- $cwd;