#!/usr/bin/perl# Copyright 2004 - Ryan Anderson <ryan@michonline.com>  GPL v2 use strict;use warnings;use Digest::MD5;require 5.006; if (@ARGV != 1) {	print <<EOT;Usage: setlocalversion <srctree>EOT	exit(1);} my ($srctree) = @ARGV;chdir($srctree); my @LOCALVERSIONS = (); # We are going to use the following commands to try and determine if this# repository is at a Version boundary (i.e, 2.6.10 vs 2.6.10 + some patches) We# currently assume that all meaningful version boundaries are marked by a tag.# We don't care what the tag is, just that something exists. # Git/Cogito store the top-of-tree "commit" in .git/HEAD# A list of known tags sits in .git/refs/tags/## The simple trick here is to just compare the two of these, and if we get a# match, return nothing, otherwise, return a subset of the SHA-1 hash in# .git/HEAD sub do_git_checks {	open(H,"<.git/HEAD") or return;	my $head = <H>;	chomp $head;	close(H); 	opendir(D,".git/refs/tags") or return;	foreach my $tagfile (grep !/^\.{1,2}$/, readdir(D)) {		open(F,"<.git/refs/tags/" . $tagfile) or return;		my $tag = <F>;		chomp $tag;		close(F);		return if ($tag eq $head);	}	closedir(D); 	push @LOCALVERSIONS, "g" . substr($head,0,8);} if ( -d ".git") {	do_git_checks();} printf "-%s\n", join("-",@LOCALVERSIONS) if (scalar @LOCALVERSIONS > 0);