scheduler: Fix cupsd activated on-demand via socket

If only the expected cups.sock is set as listener in cupsd.conf, the
array Listeners was NULL. To prevent copying the code, do the array
allocation earlier and have only one check for Listeners, in
service_checkin() which is run every time cupsd starts.

Fixes OpenPrinting#985

scheduler/conf.c

@@ -558,6 +558,18 @@ cupsdReadConfiguration(void)
 
   cupsdDeleteAllListeners();
 
+ /*
+  * Allocate array Listeners
+  */
+
+  Listeners = cupsArrayNew(NULL, NULL);
+
+  if (!Listeners)
+  {
+    fprintf(stderr, "Unable to allocate memory for array Listeners.");
+    return (0);
+  }
+
   old_remote_port = RemotePort;
   RemotePort      = 0;
 
@@ -1043,32 +1055,6 @@ cupsdReadConfiguration(void)
     }
   }
 
- /*
-  * Check that we have at least one listen/port line; if not, report this
-  * as an error and exit!
-  */
-
-#ifdef HAVE_ONDEMAND
-  if (cupsArrayCount(Listeners) == 0 && !OnDemand)
-#else
-  if (cupsArrayCount(Listeners) == 0)
-#endif // HAVE_ONDEMAND
-  {
-   /*
-    * No listeners!
-    */
-
-    cupsdLogMessage(CUPSD_LOG_EMERG,
-                    "No valid Listen or Port lines were found in the "
-		    "configuration file.");
-
-   /*
-    * Commit suicide...
-    */
-
-    cupsdEndProcess(getpid(), 0);
-  }
-
  /*
   * Set the default locale using the language and charset...
   */
@@ -3155,17 +3141,6 @@ read_cupsd_conf(cups_file_t *fp)	/* I - File to read from */
         * Allocate another listener...
 	*/
 
-        if (!Listeners)
-	  Listeners = cupsArrayNew(NULL, NULL);
-
-	if (!Listeners)
-	{
-          cupsdLogMessage(CUPSD_LOG_ERROR,
-	                  "Unable to allocate %s at line %d - %s.",
-	                  line, linenum, strerror(errno));
-          break;
-	}
-
         if ((lis = calloc(1, sizeof(cupsd_listener_t))) == NULL)
 	{
           cupsdLogMessage(CUPSD_LOG_ERROR,

scheduler/main.c

@@ -2043,7 +2043,7 @@ service_checkin(void)
     * No listeners!
     */
 
-    cupsdLogMessage(CUPSD_LOG_EMERG, "service_checkin: No listener sockets present.");
+    cupsdLogMessage(CUPSD_LOG_EMERG, "No listener sockets present.");
 
    /*
     * Commit suicide...