#!/usr/bin/perl
#
# Convert hostgroup entries in a mon configuration file
# into a local hosts file
#
# Jim Trocki, trockij@arctic.org
#
# $Id: cf-to-hosts,v 1.2 2005/04/17 07:42:27 trockij Exp $
#
#    Copyright (C) 1998, Jim Trocki
#
#    This program is free software; you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation; either version 2 of the License, or
#    (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with this program; if not, write to the Free Software
#    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
use strict;

sub resolve_hosts;
sub print_hosts;
sub read_cf;

use Getopt::Std;
use Socket;

my %resolved;

my %opt;
getopts ("hM", \%opt);

if ($opt{"h"})
{
    print <<EOF;
usage: cf-to-hosts [-M] mon.cf
  -M    pre-process with m4

EOF
    exit;
}

my $f = shift;

die "supply config file\n" if ($f eq "");

if ((my $e = read_cf ($f)) ne "")
{
    die "error reading $f: $e\n";
}

print_hosts;

exit;


sub print_hosts
{
    foreach my $host (keys %resolved)
    {
    	print "$resolved{$host}\t$host\n";
    }
}


sub resolve_hosts
{
    my ($hosts) = @_;

    my $err = 0;

    foreach my $host (split (/\s+/, $hosts))
    {
	next if (defined $resolved{$host});

	my $ip = gethostbyname ($host);

	if (!defined ($ip))
	{
	    print STDERR "could not look up $host\n";
	    $err++;
	}
	
	else
	{
	    $resolved{$host} = inet_ntoa ($ip);
	}
    }

    $err;
}


sub read_cf
{
    my $f = shift;

    if ($opt{"M"} || $f =~ /\.m4$/i)
    {
	open (IN, "m4 $f |") || return "$!";
    }

    else
    {
	open (IN, "$f") || return "$!";
    }

    my $linepart = "";
    my $l = "";
    my $acc_line = undef;
    my $ingroup = 0;

    for (;;)
    {
	last if (!defined ($linepart = <IN>));

	next if $linepart =~ /^\s*#/;

	#
	# accumulate multi-line lines (ones which are \-escaped)
	#
	if (!defined $acc_line) { $linepart =~ s/^\s*//; }

	if ($linepart =~ /^(.*)\\\s*$/)
	{
	    $acc_line .= $1;
	    chomp $acc_line;
	    next;
	}

	else
	{
	    $acc_line .= $linepart;
	}

	$l = $acc_line;
	$acc_line = undef;

	chomp $l;
	$l =~ s/^\s*//;
	$l =~ s/\s*$//;

	$linepart = "";

	if ($l eq "")
	{
	    $ingroup = 0;
	    next;
	}

	if ($l =~ /^hostgroup\s+(\S+)\s+(.*)/)
	{
		$ingroup = 1;
		resolve_hosts ($2);
		next;
	}
	
	elsif ($ingroup)
	{
	    resolve_hosts ($l);
	    next;
	}
    }

    close (IN);

    return "";
}