#!/usr/bin/perl

sub printError
{
	my $message = shift;
	&_printMessage($message,"Error: ");
}

sub printMessage
{
	my $message = shift;
	&_printMessage($message);
}

sub printOKMessage
{
	my $message = shift;
	&_printMessage($message);
}

sub _printMessage
{
	my $message = shift;
	my $prefix = shift;
	print STDERR $prefix.$message."\n";
}

sub fixUid
{
	my $new_uid = shift;
	my $new_gid = shift;
	my $found = 0;
	if(!open FD,"+<", "/etc/passwd"){
		printError("Cannot open /etc/passwd to fix permissions");
		return 0;
	}
	my $result = "";
	while(my $line = <FD>){
		my ($user,$pass,$uid,$gid,$rest) = split(/:/,$line,5);
		if(defined $rest){
			if($user eq 'www-data'){
				if($found){
					printError("multiple www-data users are in /etc/passwd, don't know what to do");
					return 0;
				}
				$found = 1;
				my $g;
				$g = defined($new_gid)?$new_gid:$gid;
				$result .= "$user:$pass:$new_uid:$g:$rest";
			}else{
				if($uid == $new_uid){
					printError("User with UID $new_uid already exists!");
					return 0;
				}else{
					$result .= $line;
				}
			}
		}else{
			$result .= $line;
		}
	}
	if(!$found){
		printError("user www-data was not found in /etc/passwd");
		return 0;
	}
	seek(FD, 0, SEEK_SET);
	truncate(FD,0);
	print FD $result;
	close(FD);

	return 1;

}

sub fixGid
{
	my $new_gid = shift;
	my $found = 0;
	if(!open FD,"+<", "/etc/group"){
		printError("Cannot open /etc/group to fix permissions");
		return 0;
	}
	my $result = "";
	while(my $line = <FD>){
		my ($group,$pass,$gid,$rest) = split(/:/,$line,4);
		if(defined $rest){
			if($group eq 'www-data'){
				if($found){
					printError("multiple www-data groups are in /etc/group, don't know what to do");
					return 0;
				}
				$found = 1;
				my $g;
				$result .= "$group:$pass:$new_gid:$rest";
			}else{
				if($gid == $new_gid){
					printError("Group with GID $new_gid already exists!");
					return 0;
				}else{
					$result .= $line;
				}
			}
		}else{
			$result .= $line;
		}
	}
	if(!$found){
		printError("group www-data was not found in /etc/group");
		return 0;
	}
	seek(FD, 0, SEEK_SET);
	truncate(FD,0);
	print FD $result;
	close(FD);

	return 1;

}

$uid = lc($ARGV[0]);
$gid = lc($ARGV[1]);
$uid = undef if($uid eq '' || $uid eq 'orig');
$gid = undef if($gid eq '' || $uid eq 'orig');

$error = 0;
$want_fix = 0;

if(defined $uid){
	$want_fix = 1;
	$error = 1 if(!&fixUid($uid,$gid));
}

if(defined $gid){
	$want_fix = 1;
	$error = 1 if(!&fixGid($gid));
}


if($want_fix){
	if(!$error){
		&printOKMessage("www-data UID set to $uid and www-data GID set to $gid successfully");
	}
}else{
	&printMessage("UID and GID was not changed");
}