Take domain sockets into account

pappl/dnssd.c

@@ -51,7 +51,7 @@ _papplPrinterRegisterDNSSDNoLock(
   const char		*papermax;	// PaperMax string value (legacy)
 
 
-  if (!printer->dns_sd_name || !printer->system->is_running || (printer->system->options & PAPPL_SOPTIONS_NO_DNS_SD) || !system->reghost)
+  if (!printer->dns_sd_name || !printer->system->is_running || (printer->system->options & PAPPL_SOPTIONS_NO_DNS_SD) || !system->reghost || !printer->system->reghost)
     return (false);
 
   papplLogPrinter(printer, PAPPL_LOGLEVEL_DEBUG, "Registering DNS-SD name '%s' on '%s'", printer->dns_sd_name, printer->system->reghost);

pappl/system-accessors.c

@@ -2598,8 +2598,10 @@ papplSystemSetPrinterDrivers(
 //                                 registered.
 //
 // This function sets the hostname under which services will be registered - it can
-// be localhost or the current hostname, so it denies setting of different hostname
-// to prevent masquerading itself as a different machine.
+// be localhost or the current hostname, otherwise registration hostname will be empty
+// and service registration will be disabled (to prevent publishing service for
+// different machine or when application listens on domain socket). In case 'name' is NULL,
+// the current hostname is set as registration hostname.
 //
 
 void
@@ -2616,18 +2618,20 @@ papplSystemSetRegHostName(
 
   if (system->hostname)
   {
-    if (name && (!strcasecmp(system->hostname, name) || !strcasecmp(name, "localhost")))
-      value = name;
-
-    if (!value)
+    if (!name)
       value = system->hostname;
+    else if (!strcasecmp(name, system->hostname))
+      goto end;
+    else if (!strcasecmp(name, "localhost"))
+      value = "localhost";
 
     if (system->reghost)
       free(system->reghost);
 
-    system->reghost = strdup(value);
+    system->reghost = value ? strdup(value) : NULL;
   }
 
+end:
   _papplRWUnlock(system);
 }