In auto-shutdown mode ("-l") scheduler keeps running on subscriptions for push notifications

[michaelrsweet]

Version: 2.1-current
CUPS.org User: till.kamppeter

I use CUPS to implement printing functionality on mobile devices. To save resources I start CUPS on-demand and let CUPS shut down automatically when it gets idle ("-l" command line option).

Problem is that if there is an application's subscription for push notifications (like D-Bus) CUPS keeps running as long as the subscription is there. It should shut down when running out of jobs, ignoring the presence of the subscription.

[michaelrsweet]

CUPS.org User: mike

Fixed in Subversion repository.

[michaelrsweet]

CUPS.org User: till.kamppeter

Are you sure that the attached patch is fixing this bug?

[michaelrsweet]

CUPS.org User: mike

Yes, the issue was that select_timeout() (in main.c) was lowering the timeout when subscriptions were present, preventing idle exit. I removed that code and added code in ipp.c to auto-expire subscriptions as needed (before similar code is used in the main loop - an IPP Get-Subscriptions or Get-Subscription-Attributes request could come in before the main loop expiration code was executed...)

[michaelrsweet]

"str4754.patch":

Index: scheduler/ipp.c
===================================================================
--- scheduler/ipp.c (revision 13037)
+++ scheduler/ipp.c (working copy)
@@ -3,7 +3,7 @@
  *
  * IPP routines for the CUPS scheduler.
  *
- * Copyright 2007-2015 by Apple Inc.
+ * Copyright 2007-2016 by Apple Inc.
  * Copyright 1997-2007 by Easy Software Products, all rights reserved.
  *
  * This file contains Kerberos support code, copyright 2006 by
@@ -7255,6 +7255,12 @@
                   con, con->number, sub_id);

  /*
+  * Expire subscriptions as needed...
+  */
+
+  cupsdExpireSubscriptions(NULL, NULL);
+
+ /*
   * Is the subscription ID valid?
   */

@@ -7404,6 +7410,12 @@
   }

  /*
+  * Expire subscriptions as needed...
+  */
+
+  cupsdExpireSubscriptions(NULL, NULL);
+
+ /*
   * Copy the subscription attributes to the response using the
   * requested-attributes attribute that may be provided by the client.
   */
Index: scheduler/main.c
===================================================================
--- scheduler/main.c    (revision 13037)
+++ scheduler/main.c    (working copy)
@@ -3,7 +3,7 @@
  *
  * Main loop for the CUPS scheduler.
  *
- * Copyright 2007-2015 by Apple Inc.
+ * Copyright 2007-2016 by Apple Inc.
  * Copyright 1997-2007 by Easy Software Products, all rights reserved.
  *
  * These coded instructions, statements, and computer programs are the
@@ -1573,7 +1573,6 @@
   time_t       now;        /* Current time */
   cupsd_client_t   *con;       /* Client information */
   cupsd_job_t      *job;       /* Job information */
-  cupsd_subscription_t *sub;       /* Subscription information */
   const char       *why;       /* Debugging aid */


@@ -1711,19 +1710,6 @@
 #endif /* HAVE_MALLINFO */

  /*
-  * Expire subscriptions as needed...
-  */
-
-  for (sub = (cupsd_subscription_t *)cupsArrayFirst(Subscriptions);
-       sub;
-       sub = (cupsd_subscription_t *)cupsArrayNext(Subscriptions))
-    if (!sub->job && sub->expire && sub->expire < timeout)
-    {
-      timeout = sub->expire;
-      why     = "expire subscription";
-    }
-
- /*
   * Adjust from absolute to relative time.  We add 1 second to the timeout since
   * events occur after the timeout expires, and limit the timeout to 86400
   * seconds (1 day) to avoid select() timeout limits present on some operating
Index: scheduler/subscriptions.c
===================================================================
--- scheduler/subscriptions.c   (revision 13037)
+++ scheduler/subscriptions.c   (working copy)
@@ -657,6 +657,8 @@
   curtime = time(NULL);
   update  = 0;

+  cupsdLogMessage(CUPSD_LOG_INFO, "Expiring subscriptions...");
+
   for (sub = (cupsd_subscription_t *)cupsArrayFirst(Subscriptions);
        sub;
        sub = (cupsd_subscription_t *)cupsArrayNext(Subscriptions))

[michaelrsweet]

CUPS.org User: till.kamppeter

Tested your patch on CUPS 2.1.x of Ubuntu Xenial and it works. Thank you very much.