#!/sw/bin/perl

$self = $0;
$self =~ s!^.*/!!;

$target = "/etc/hosts";

$mnt_target = "/mnt";
$mnt_source = "sunbi1:/s/tftpboot/host";

$rc = system("/usr/etc/mount $mnt_source $mnt_target") >> 8;

if ($rc)
{
    die "$self: can't mount '$mnt_source' to '$mnt_target': $rc\n";
}

unless (opendir(HOSTS, $mnt_target))
{
    die "$self: can't read directory '$mnt_source': $!\n";
}

@hosts = sort readdir(HOSTS);

closedir(HOSTS);

foreach $file (@hosts)
{
    next if ($file eq '.');
    next if ($file eq '..');
    $host='';
    $alias='';
    $domain='';
    $hostaddr='';
    $hostname='';
    unless (open(HOST, "<$mnt_target/$file"))
    {
        warn "$self: can't read '$mnt_source/$file': $!\n";
        next;
    }
    while (<HOST>)
    {
        chop;
        ($var, $value) = split(/\s*=\s*/);
        if (($var eq "ip-nr") &&
          ($value =~ /^(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})/))
        {
            $host = sprintf("%.2X%.2X%.2X%.2X", $1, $2, $3, $4);
            $hostaddr = sprintf("%d.%d.%d.%d", $1, $2, $3, $4);
        }
        if ($var eq "hostname") { $hostname=$value; }
        if ($var eq "domain") { $domain=$value; }
        if ($var eq "alias") { $alias=$value; }
    }
    close(HOST);
    if (($host ne '') && ($hostname ne ''))
    {
        if (($domain ne '') && ($hostname !~ /\./))
        {
            $hostname = "$hostname.$domain $hostname";
#           $hostname .= " $hostname.$domain";
        }
        if (defined $addr{$host})
        {
            warn "$self: $addr{$host} ($name{$host}) redefined as '$hostname' in '$file'!\n";
            if ($alias{$host} ne '')
            {
                $alias{$host} .= " $hostname";
            }
            else
            {
                $alias{$host} = $hostname;
            }
        }
        else
        {
            $addr{$host} = $hostaddr;
            $name{$host} = $hostname;
            $alias{$host} = $alias;
        }
    }
}

undef @hosts;

$rc = system("/usr/etc/umount $mnt_target") >> 8;

if ($rc)
{
    die "$self: can't unmount '$mnt_source' at '$mnt_target': $rc\n";
}

$ext = '000';
$backup = "$target.$ext";
while (-e $backup)
{
    $ext++;
    $backup = "$target.$ext";
}

unless (open(OLDHOSTS, "<$target"))
{
    die "$self: can't read '$target': $!\n";
}
unless (rename($target,$backup))
{
    die "$self: can't rename '$target' to '$backup': $!\n";
}
unless (open(NEWHOSTS, ">$target"))
{
    die "$self: can't write '$target': $!\n";
}

while (<OLDHOSTS>)
{
    last if /DO NOT MODIFY OR RELOCATE THIS LINE/;
    print NEWHOSTS;
}

close(OLDHOSTS);

print NEWHOSTS <<"VERBATIM";
# DO NOT MODIFY OR RELOCATE THIS LINE -
# it serves as an anchor for the automatic generation of what follows!
#
# Entries below are generated automatically.
# DO NOT EDIT THE SECTION BELOW! CHANGES WILL BE LOST!
# Edit the source files in '$mnt_source' instead!
#
#######################################
#
VERBATIM

foreach $host (sort keys(%name))
{
    if ($alias{$host} ne '')
    {
        $name{$host} .= " $alias{$host}";
    }
    printf(NEWHOSTS "%-16s %s\n", $addr{$host}, $name{$host});
}

close(NEWHOSTS);

__END__