fix for large data

DDNS.pm

@@ -8,7 +8,7 @@ use JSON::PP qw/decode_json encode_json/;
 
 memoize('_gethosts');
 
-our $VERSION = '0.6';
+our $VERSION = '0.7';
 
 # Control plane update keyfile (zone-management-key)
 our $keyfile = '/etc/bind/zone-management.key';
@@ -83,17 +83,28 @@ sub __docmd {
     close $tmpfh;
 
     my $fh;
-    open($fh, "|nsupdate -k $this->{keyfile} > $filename")
+    # Capture BOTH stdout and stderr into the temp file so errors are visible,
+    # and so we can fail the caller when nsupdate fails.
+    open($fh, "|nsupdate -k $this->{keyfile} > $filename 2>&1")
         || die "Can't open nsupdate: $!";
 
     print $fh "server localhost\nzone private.invalid.\n$cmd\nshow\nsend\n";
-    close $fh;
 
-    open($fh, $filename) || die "Can't re-open tmpfile $filename: $!";
+    # If nsupdate fails, close() will return false and $? will be non-zero.
-    while (<$fh>) {
+    close($fh) or do {
+        open(my $rfh, $filename) || die "Can't re-open tmpfile $filename: $!";
+        my $out = do { local $/; <$rfh> };
+        close $rfh;
+        unlink $filename;
+        die "nsupdate failed (exit=$?):\n$out\n";
+    };
+
+    # Echo nsupdate output (useful for operators/logs)
+    open(my $rfh, $filename) || die "Can't re-open tmpfile $filename: $!";
+    while (<$rfh>) {
         print;
     }
-    close $fh;
+    close $rfh;
 
     unlink $filename;
 }
@@ -157,12 +168,22 @@ sub _parse_txt_payload {
     return ($v, $payload);
 }
 
+# Produce BIND nsupdate TXT RDATA as one or more quoted strings.
+# BIND limits each TXT "character-string" to 255 bytes, so we chunk.
 sub _quote_txt_rdata {
     my ($s) = @_;
     $s = '' unless defined $s;
+
+    # Escape for inclusion inside a quoted TXT character-string
     $s =~ s/\\/\\\\/g;
     $s =~ s/\"/\\\"/g;
-    return "\"$s\"";
+
+    # Conservative chunk size to stay well under 255 bytes after escaping
+    my $chunk_len = 200;
+    my @chunks = ($s =~ /.{1,$chunk_len}/gs);
+
+    # Emit as: "chunk1" "chunk2" "chunk3"
+    return join(' ', map { "\"$_\"" } @chunks);
 }
 
 sub _gethosts {
@@ -231,7 +252,10 @@ sub set {
     _lookupOrDie($this, $dom, $type);
     my $fqdn = _fqdn($dom, $type);
 
-    $this->__docmd("update delete $fqdn TXT\nupdate add $fqdn 60 TXT " . _quote_txt_rdata($txt_payload));
+    $this->__docmd(
+        "update delete $fqdn TXT\n" .
+        "update add $fqdn 60 TXT " . _quote_txt_rdata($txt_payload)
+    );
     $this->cleanup();
 }
 
@@ -313,7 +337,7 @@ sub set_config {
     my ($this, $cfg_hashref) = @_;
     die "Config must be a hashref" unless (defined $cfg_hashref && ref($cfg_hashref) eq 'HASH');
 
-    # Always store canonical JSON
+    # Always store compact canonical JSON (encode_json is compact)
     my $txt = encode_json($cfg_hashref);
 
     my $dom  = "global.";