File modversions of Package kernel-source

#! /usr/bin/perl -w

use File::Basename;
use File::Path;
use File::Find;
use Getopt::Long;
use strict;

my %symbol_type_name = (
    n => 'normal', t => 'typedef', e => 'enum', s => 'struct', u => 'union',
    E => 'enum constant'
);

my %definitions;
my %override;
my %override_locally;
my %locally_unknown;
my %locally_defined;

sub expand_types($);
sub expand_types($) {
    my ($definition) = @_;
    local ($_, $1, $2);

    my @defn = split ' ', $definition;
    for (@defn[1..$#defn]) {
	if (/^(.)#(.*)/) {
	    #print "<<$defn[0] : $_>>\n";
	    next if exists $locally_defined{$_};
	    $locally_defined{$_} = 1;

	    if ($locally_unknown{$_}) {
                print "override " if $override_locally{$_};
		print "$_ $symbol_type_name{$1} $2 { UNKNOWN } \n";
	    } else {
		if (!exists $definitions{$_}) {
		    die "Missing definition of $symbol_type_name{$1} $2\n";
		}
		expand_types("$_ $definitions{$_}");
	    }
	}
    }
    print "override " if $override_locally{$defn[0]};
    print "$definition\n";
}

sub pack_dump($$) {
    my ($dir, $ext) = @_;
    my @files;

    $ext = ".symtypes" unless defined $ext;
    $dir =~ s/\/+$//;

    find(sub ($) { /\Q$ext\E$/ && push @files, $File::Find::name}, $dir);
    map { s/^\Q$dir\E\/(.*)\Q$ext\E$/$1/ } @files;

    foreach my $file (sort @files) {
	print "/* $file.o */\n";

	local *FD;
	open FD, "< $dir/$file$ext"
	    or die "$dir/$file$ext: $!\n";
	while (<FD>) {
	    chomp;

	    my $override = "";
	    if (s/^override //) {
		$override = $&;
	    }

	    if (/^(\S)#(\S+)\s*(.*)/) {
		my $sym = "$1#$2";
		my $definition = $3;

		if (/^$sym\s+$symbol_type_name{$1}\s+$2\s+{\s+UNKNOWN\s+}\s*$/) {
		    $_ = $override . substr($sym, 0, 1) . "##" . substr($sym, 2);
		} else {
		    if (exists $definitions{$sym} && $definitions{$sym} eq $definition) {
			if (($override ne "") == (exists $override{$sym})) {
			    next;
			}
			$_ = "$override$sym";
		    } else {
			$definitions{$sym} = $definition;
			if ($override eq "") {
			    delete $override{$sym};
			} else {
			    $override{$sym} = 1;
			    $_ = "$override$_";
			}
		    }
		}
	    } elsif ($override) {
		    $_ = "$override$_";
	    }
	    print "$_\n";
	}
	close FD;
	print "\n";
    }
}

sub unpack_dump($$) {
    my ($dir, $ext) = @_;

    $ext = ".symref" unless defined $ext;

    while (<STDIN>) {
	next if /^$/;
	chomp;

	if (/^\/\* (.*)\.o \*\//) {
	    close STDOUT;
	    mkpath(dirname("$dir/$1$ext"));
	    open STDOUT, "> $dir/$1$ext"
		or die "$dir/$1$ext: $!\n";
	    %locally_defined = ();
	    %locally_unknown = ();
	    %override_locally = %override;
	    next;
	}

	my $override = /^override\s/;
	s/^override\s//;

	if (/^([^ ])#(#?)([^ ]+) *(.*)$/) {
	    my $sym = "$1#$3";

	    if ($4 ne "") {
		if (/\s+{\s+UNKNOWN\s+}\s*$/) {
		    $locally_unknown{$sym} = 1;
		    $override_locally{$sym} = $override;
		} else {
		    $definitions{$sym} = $4;
		    $locally_unknown{$sym} = 0;
		    $override{$sym} = $override;
		    $override_locally{$sym} = $override;
		}
	    } else {
		$locally_unknown{$sym} = ($2 ne "");
		$override_locally{$sym} = $override;
	    }
	    next;
	} elsif (/^([^# ]*)/) {
		$override_locally{$1} = $override;
	}
	expand_types($_);
    }
}

my ($pack, $unpack, $ext);
GetOptions("pack" => \$pack, "unpack" => \$unpack, "ext:s" => \$ext)
    && ($pack || $unpack) && @ARGV == 1
    or die "USAGE:\t$0 [--ext extension] --pack {dir} > file\n" .
		 "\t$0 [--ext extension] --unpack {dir} < file\n";

pack_dump($ARGV[0], $ext) if $pack;
unpack_dump($ARGV[0], $ext) if $unpack;