#!/usr/bin/perl
use strict;

my $kdir=shift or die "should specify a kernel dir";
my $infile=shift or die "should specify an input config file";
my $outfile=shift or die "should specify an output config file";

my $out;

sub check_spin_lock()
{
	my $file = "$kdir/include/linux/netdevice.h";
	my $old_syntax = 1;

	open INNET, "<$file" or die "File not found: $file";
	while (<INNET>) {
		if (m/netif_tx_lock_bh/) {
			$old_syntax = 0;
			last;
		}
	}

	if ($old_syntax) {
		$out.= "\n#define OLD_XMIT_LOCK 1\n";
	}
	close INNET;
}

sub check_snd_ctl_boolean_mono_info()
{
	my $file = "$kdir/include/sound/control.h";
	my $old_syntax = 1;

	open INNET, "<$file" or die "File not found: $file";
	while (<INNET>) {
		if (m/snd_ctl_boolean_mono_info/) {
			$old_syntax = 0;
			last;
		}
	}

	if ($old_syntax) {
		$out.= "\n#define COMPAT_SND_CTL_BOOLEAN_MONO 1\n";
	}
	close INNET;
}

sub check_other_dependencies()
{
	check_spin_lock();
	check_snd_ctl_boolean_mono_info();
}

# Do the basic rules
open IN, "<$infile" or die "File not found: $infile";

$out.= "#ifndef __CONFIG_COMPAT_H__\n";
$out.= "#define __CONFIG_COMPAT_H__\n\n";
$out.= "#include <linux/autoconf.h>\n\n";
while(<IN>) {
	next unless /^(\S+)\s*:= (\S+)$/;
	$out.= "#undef $1\n";
	$out.= "#undef $1_MODULE\n";
	if($2 eq "n") {
		next;
	} elsif($2 eq "m") {
		$out.= "#define $1_MODULE 1\n";
	} elsif($2 eq "y") {
		$out.= "#define $1 1\n";
	} else {
		$out.= "#define $1 $2\n";
	}
}
close IN;

check_other_dependencies();

open OUT, ">$outfile" or die 'Unable to write $outfile';
print OUT "$out\n#endif\n";
close OUT