publish-cups-dns

#!/usr/bin/perl


# Script to push discovery information about CUPS printer
#   queues into wide-area DNS for DNS-SD

# Hostname/IP of your DNS server
$DNSSRV='';

# Set this to '' if cups is installed in /
#$CUPS='/usr/local/cups';
$CUPS='';

# Hostname / IP of your CUPS server
$CUPS_SERVER='printhost';

# Space-separated list of domains to push DNS-SD info into
$SD_DOMAINS="dom1.example.com dom2.example.com";

####################################################################
#
#  Nothing below this line should need to be changed
#    unless your CUPS install is weird. You have been warned!
#

use Switch;

$hostname=`hostname -f`;
chomp($hostname);
($cupshost, $myDomain)=split('\.', $hostname, 2);
$PPDS="$CUPS/etc/cups/ppd";

if($ARGV[0] eq "-d") { $delonly=1; shift @ARGV; }
if($ARGV[0] eq "-g") { $dbg=1 ; shift @ARGV };
if($ARGV[0] eq "-v") { $dbg=1 ; shift @ARGV }
if($ARGV[0] eq "-n") {
    $dryrun=1;
} else {
    $dryrun=0;
}

# Tell the cups tools which server to query
$ENV{'CUPS_SERVER'}=$CUPS_SERVER;


# Start the nsupdate process
if ($dryrun) {
    open(NDC, ">/tmp/dns-update.log") || die ("Cannot create dry run logfile!\n");
} else {
    open(NDC, "|tee /tmp/commands | /usr/bin/nsupdate -v >/tmp/dns-update.log 2>&1") || die ("Fatal - cannot start 'nsupdate'!\n");
}

foreach $DOM (split(' ', $SD_DOMAINS)) {

    #######  Determine the DNS master to send updates to  ########
    if ($DNSSRV eq '') {
	$res=`dig +short $DOM IN SOA`;
	chomp($res);
	if ($res eq '') {
	    die ("Error: can't determine DNS master for zone $DOM\n");
	} else {
	    $DNSSRV=$res;
	    $DNSSRV=~s/\. .*//;
	    print "Sending updates to server $DNSSRV\n" if ($dbg);
	}
    }
    print (NDC "server $DNSSRV\n") || die ("Error writing to nsupdate process!\n");

    #######  Check to make sure the domain is set up for wide-area DNS-SD  ########
    foreach $pointer ('b', 'lb', 'db') {
	$res=`dig +short $pointer._dns-sd._udp.$DOM IN PTR`;
	chomp($res);
	print "$pointer pointer is $res\n" if ($dbg);
	if ($res ne "$DOM.") {
	    print "Warning: domain $DOM is missing DNS-SD $pointer pointer\n";
	    print "   Attempting to add\n";
	    print (NDC "update add $pointer._dns-sd._udp.$DOM. 600 IN PTR $DOM.\n");
	    print (NDC "send\n");
	}
    }

    ######  Delete all existing cups data from dns  ################
    print ("Clearing old dns-sd cups data...\n") if ($dbg);
    print (NDC "update delete _cups._sub._ipp._tcp.$DOM IN PTR\n");
    print (NDC "update delete _ipp._tcp.$DOM. IN PTR\n");
    print (NDC "send\n");
    open (DIG, "dig \@$DNSSRV $DOM in axfr|");
    while ($dig=<DIG>) {
	if ($dig=~/_tcp.*TXT/){
	    ($prt) = split(/ /, $dig);
	    $prt=~s/\..*//;
	    $printers{$prt}=1;
	}
    }
    close(DIG);
    foreach $prt (keys(%printers)) {
	print ("Removing old printer: $prt._ipp._tcp.$DOM\n") if ($dbg);
	print (NDC "update delete $prt._ipp._tcp.$DOM IN ANY\n");
    }
    print (NDC "send\n");


    ##########  Publish the new cups DNS-SD info  ############
    if (! -e "$CUPS/etc/cups/printers.conf") {
	die ("Error: Cannot find cups or printers.conf!\n");
    }
    open(PRN, "< $CUPS/etc/cups/printers.conf");
    while($lp=<PRN>) {
	chomp($lp);
	print ("Parsing line $lp\n") if ($dbg);
	if ($lp=~/\<(Default)*Printer /) {
	    # Found a new printer
	    $inlp=1;  $prod="";
	    $prt=$lp;
	    $prt=~s/\<.*Printer (.*)\>/$1/;
	    print ("Found printer $prt\n") if ($dbg);

	    $ppd=$PPDS."/".$prt.".ppd";
	    print ("  PPD file is $ppd\n") if ($dbg);
	    if (! -e "$ppd") {
		print (" Printer $prt not a real printer - skipping\n") if ($dbg);
		next;
	    }
	}
	if ($lp=~/^Info/) {
	    #$ty=substr($lp, 5);
	    print ("  Info: $ty\n") if ($dbg);
	}
	if ($lp=~/^Location/) {
	    $note=substr($lp, 9);
	    print ("  Location: $note\n") if ($dbg);
	}
	if ($lp=~/^Shared Yes/) {
	    $shared=1
	}
	if ($lp=~/^Shared No/) {
	    $shared=0
	}
	if ($lp=~/\<\/Printer\>/) {
	    # End of printer block - write the config
	    if (!$inlp) {
		# Bad printer block - bail out!
		die ("Error: Malformed printers.conf!\n");
	    }

	    # Find product type from the PPD file
	    open (PPD, "<$ppd") || die ("Error: Cannot find PPD for $prt!\n");
	    while(<PPD>) {
		if (/^*Product:\s/) {
		    chomp();
		    $prod=$_;
		    $prod=~s/\*Product:\s*"(.*)"/$1/;
		    $prod=~s/\cM//;
		    $ty=$prod;
		    $ty=~s/[()]//g;
		    print ("  Printer is a $prod\n") if ($dbg);
		}
	    }
	    close (PPD);

	    # Try to read duplex capability from lpoptions
	    $duplex=0; $add="";
	    open (INFO, "lpoptions -p $prt -l|");
	    while(<INFO>) {
		if (/Duplex Unit.*\*/) {
		    chomp();
		    $dup=$_;
		    $dup=~s/.*\*(\w+)\s*.*/$1/;
		    switch ($dup) {
			case "False"	{ $duplex=0 };
			case "True"		{ $duplex=1; $add="\"Duplex=T\"" };
			case "Installed"	{ $duplex=1; $add="\"Duplex=T\"" };
			case "NotInstalled"	{ $duplex=0 };
		    }
		}
	    }
	    close (INFO);

	    if ($prod eq "") {
		print ("Error - no model info for $prt!\n");
		$inlp=0;
		next;
	    }

	    if (!$delonly)  { 
		if ($shared) {
		    print "Adding $prt to $DOM...\n" if ($dbg);
		    print (NDC "update add _ipp._tcp.$DOM. 60 IN PTR $prt._ipp._tcp.$DOM.\n");
		    print (NDC "update add _cups._sub._ipp._tcp.$DOM. 60 IN PTR $prt._ipp._tcp.$DOM.\n");
		    print (NDC "update add $prt._ipp._tcp.$DOM. 60 IN SRV 0 0 631 $cupshost.\n");
		    print (NDC "update add $prt._ipp._tcp.$DOM. 60 IN TXT \"txtvers=1\" \"qtotal=1\" \"rp=printers/$prt\" \"ty=$ty\" \"note=$note\" \"product=$prod\" $add\n");
		    print (NDC "send\n");
		}
	    }
	    $inlp=0;
	}
    }

} # End $SD_DOMAINS loop

print (NDC "quit\n");
close (NDC);
close (PRN);