cups-browsed.c: Make NotifLeaseDuration configurable and renew after half the lease...

1) NotifLeaseDuration directive for cups-browsed.conf - it will make
   lease duration for notifications configurable by users. IMO it is not
   useful for regular users, but it is helpful during sanity testing
   (for verifying that we actually renew the subscription when time
   comes). The current hardcoded 1 day is unusuable for that :( .
   I implemented the lowest threshold to 300s to prevent a possible DoS.
2) Subscription renewal is set to happen in the middle of NotifLeaseDuration,
   not one minute before lease expiration. This was a problem on busy servers,
   where cups-browsed was busy and wasn't able to renew the subscription
   before cupsd removed it. Then if some jobs had come before the subscription
   was created again, the queue got disabled. The proposed approach is based
   on behavior of DHCP.

(cherry picked from commit d90a4fc57b00b4a1f6c196bcb96025251b555dd9)

diff --git a/utils/cups-browsed.c b/utils/cups-browsed.c
index d1c3bde93066da6314405209b7a648d34f29b692..4c0b3fdf1a279afca14d510047955104cc249e90 100644 (file)
--- a/utils/cups-browsed.c
+++ b/utils/cups-browsed.c
@@ -142,7 +142,6 @@ static int  ldap_rebind_proc(LDAP *RebindLDAPHandle,
 #define TIMEOUT_REMOVE      -1
 #define TIMEOUT_CHECK_LIST   2
 
-#define NOTIFY_LEASE_DURATION (24 * 60 * 60)
 #define CUPS_DBUS_NAME "org.cups.cupsd.Notifier"
 #define CUPS_DBUS_PATH "/org/cups/cupsd/Notifier"
 #define CUPS_DBUS_INTERFACE "org.cups.cupsd.Notifier"
@@ -490,6 +489,7 @@ static int autoshutdown_timeout = 30;
 static autoshutdown_inactivity_type_t autoshutdown_on = NO_QUEUES;
 static guint autoshutdown_exec_id = 0;
 static const char *default_printer = NULL;
+static unsigned int notify_lease_duration = 86400;
 
 static int debug_stderr = 0;
 static int debug_logfile = 0;
@@ -4978,7 +4978,7 @@ create_subscription ()
   ippAddString (req, IPP_TAG_SUBSCRIPTION, IPP_TAG_URI,
                "notify-recipient-uri", NULL, "dbus://");
   ippAddInteger (req, IPP_TAG_SUBSCRIPTION, IPP_TAG_INTEGER,
-                "notify-lease-duration", NOTIFY_LEASE_DURATION);
+                "notify-lease-duration", notify_lease_duration);
 
   resp = cupsDoRequest (conn, req, "/");
   if (!resp || cupsLastError() != IPP_STATUS_OK) {
@@ -5021,7 +5021,7 @@ renew_subscription (int id)
   ippAddString (req, IPP_TAG_SUBSCRIPTION, IPP_TAG_URI,
                "notify-recipient-uri", NULL, "dbus://");
   ippAddInteger (req, IPP_TAG_SUBSCRIPTION, IPP_TAG_INTEGER,
-                "notify-lease-duration", NOTIFY_LEASE_DURATION);
+                "notify-lease-duration", notify_lease_duration);
 
   resp = cupsDoRequest (conn, req, "/");
   if (!resp || cupsLastError() != IPP_STATUS_OK) {
@@ -11820,6 +11820,15 @@ read_configuration (const char *filename)
       } else
        debug_printf("Invalid %s value: %d\n",
                     line, t);
+    } else if (!strcasecmp(line, "NotifLeaseDuration") && value) {
+      int t = atoi(value);
+      if (t >= 300) {
+         notify_lease_duration = t;
+       debug_printf("Set %s to %d sec.\n",
+                    line, t);
+      } else
+       debug_printf("Invalid %s value: %d\n",
+                    line, t);
     } else if (!strcasecmp(line, "HttpMaxRetries") && value) {
       int t = atoi(value);
       if (t > 0) {
@@ -12700,7 +12709,7 @@ int main(int argc, char*argv[]) {
   /* Subscribe to CUPS' D-Bus notifications and create a proxy to receive
      the notifications */
   subscription_id = create_subscription ();
-  g_timeout_add_seconds (NOTIFY_LEASE_DURATION - 60,
+  g_timeout_add_seconds (notify_lease_duration / 2,
                         renew_subscription_timeout,
                         &subscription_id);
   cups_notifier = cups_notifier_proxy_new_for_bus_sync (G_BUS_TYPE_SYSTEM,

diff --git a/utils/cups-browsed.conf.5 b/utils/cups-browsed.conf.5
index 3f2ff807e0a512afecbbfab46ba5a65a9c5384c7..7e6ee3bff8596b3772a9eb6c03de8e639d64e612 100644 (file)
--- a/utils/cups-browsed.conf.5
+++ b/utils/cups-browsed.conf.5
@@ -994,6 +994,17 @@ shutdown.
 
 .fam T
 .fi
+NotifLeaseDuration defines how long the D-BUS subscription created by cups-browsed
+in cupsd will last before cupsd cancels it. The default value is 1 day
+in seconds - 86400. The subscription renewal is set to happen after half of
+NotifLeaseDuration passed. The D-BUS notifications are used for watching over queues
+and doing specific actions when a D-BUS notification comes.
+.PP
+.nf
+.fam C
+        NotifLeaseDuration 86400
+.fam T
+.fi
 .SH SEE ALSO
 
 \fBcups-browsed\fP(8)

diff --git a/utils/cups-browsed.conf.in b/utils/cups-browsed.conf.in
index e89d3251678581a518dd667f72c5e501ae3fcaaa..ee2f5bf34e56c856e779e3a59db0335fae2dfa9f 100644 (file)
--- a/utils/cups-browsed.conf.in
+++ b/utils/cups-browsed.conf.in
@@ -766,3 +766,11 @@ BrowseRemoteProtocols @BROWSEREMOTEPROTOCOLS@
 # on the size of the file.
 
 # DebugLogFileSize 300
+
+# NotifLeaseDuration defines how long the D-BUS subscription created by cups-browsed
+# in cupsd will last before cupsd cancels it. The default value is 1 day
+# in seconds - 86400. The subscription renewal is set to happen after half of
+# NotifLeaseDuration passed. The D-BUS notifications are used for watching over queues
+# and doing specific actions when a D-BUS notification comes.
+
+# NotifLeaseDuration 86400