fix #6956 in exchange

contrib/gana

@@ -1 +1 @@
-Subproject commit efb2a1fd64e17159c56ff3674083837b5a657a64
+Subproject commit 689c91490ae14721a9ad7969d8fcbc0b982488e8

src/exchange/taler-exchange-httpd.c

@@ -1382,8 +1382,9 @@ do_shutdown (void *cls)
   TEH_reserves_get_cleanup ();
   if (NULL != mhd)
     MHD_stop_daemon (mhd);
-  TALER_EXCHANGEDB_plugin_unload (TEH_plugin);
   TEH_WIRE_done ();
+  TEH_keys_finished ();
+  TALER_EXCHANGEDB_plugin_unload (TEH_plugin);
 }
 
 
@@ -1425,6 +1426,13 @@ run (void *cls,
     GNUNET_SCHEDULER_shutdown ();
     return;
   }
+  if (GNUNET_OK !=
+      TEH_wire_init ())
+  {
+    global_ret = EXIT_FAILURE;
+    GNUNET_SCHEDULER_shutdown ();
+    return;
+  }
 
   TEH_load_terms (TEH_cfg);
   GNUNET_SCHEDULER_add_shutdown (&do_shutdown,

src/exchange/taler-exchange-httpd_keys.c

@@ -21,6 +21,7 @@
 #include "platform.h"
 #include "taler_json_lib.h"
 #include "taler_mhd_lib.h"
+#include "taler_dbevents.h"
 #include "taler-exchange-httpd.h"
 #include "taler-exchange-httpd_keys.h"
 #include "taler-exchange-httpd_responses.h"
@@ -349,6 +350,12 @@ static struct TEH_KeyStateHandle *key_state;
  */
 static uint64_t key_generation;
 
+/**
+ * Handler listening for wire updates by other exchange
+ * services.
+ */
+static struct GNUNET_DB_EventHandler *keys_eh;
+
 /**
  * Head of DLL of suspended /keys requests.
  */
@@ -867,9 +874,35 @@ destroy_key_state (struct TEH_KeyStateHandle *ksh,
 }
 
 
-int
+/**
+ * Function called whenever another exchange process has updated
+ * the keys data in the database.
+ *
+ * @param cls NULL
+ * @param extra unused
+ * @param extra_size number of bytes in @a extra unused
+ */
+static void
+keys_update_event_cb (void *cls,
+                      const void *extra,
+                      size_t extra_size)
+{
+  (void) cls;
+  (void) extra;
+  (void) extra_size;
+  key_generation++;
+  TEH_resume_keys_requests (false);
+}
+
+
+enum GNUNET_GenericReturnValue
 TEH_keys_init ()
 {
+  struct GNUNET_DB_EventHeaderP es = {
+    .size = htons (sizeof (es)),
+    .type = htons (TALER_DBEVENT_EXCHANGE_KEYS_UPDATED),
+  };
+
   if (GNUNET_OK !=
       GNUNET_CONFIGURATION_get_value_time (TEH_cfg,
                                            "exchange",
@@ -881,6 +914,16 @@ TEH_keys_init ()
                                "SIGNKEY_LEGAL_DURATION");
     return GNUNET_SYSERR;
   }
+  keys_eh = TEH_plugin->event_listen (TEH_plugin->cls,
+                                      GNUNET_TIME_UNIT_FOREVER_REL,
+                                      &es,
+                                      &keys_update_event_cb,
+                                      NULL);
+  if (NULL == keys_eh)
+  {
+    GNUNET_break (0);
+    return GNUNET_SYSERR;
+  }
   return GNUNET_OK;
 }
 
@@ -888,12 +931,18 @@ TEH_keys_init ()
 /**
  * Fully clean up our state.
  */
-void __attribute__ ((destructor))
+void
 TEH_keys_finished ()
 {
   if (NULL != key_state)
     destroy_key_state (key_state,
                        true);
+  if (NULL != keys_eh)
+  {
+    TEH_plugin->event_listen_cancel (TEH_plugin->cls,
+                                     keys_eh);
+    keys_eh = NULL;
+  }
 }
 
 
@@ -1719,6 +1768,15 @@ build_key_state (struct HelperState *hs,
 void
 TEH_keys_update_states ()
 {
+  struct GNUNET_DB_EventHeaderP es = {
+    .size = htons (sizeof (es)),
+    .type = htons (TALER_DBEVENT_EXCHANGE_KEYS_UPDATED),
+  };
+
+  TEH_plugin->event_notify (TEH_plugin->cls,
+                            &es,
+                            NULL,
+                            0);
   key_generation++;
   TEH_resume_keys_requests (false);
 }

src/exchange/taler-exchange-httpd_keys.h

@@ -192,6 +192,13 @@ void
 TEH_keys_denomination_revoke (const struct GNUNET_HashCode *h_denom_pub);
 
 
+/**
+ * Fully clean up keys subsystem.
+ */
+void
+TEH_keys_finished (void);
+
+
 /**
  * Resumse all suspended /keys requests, we may now have key material
  * (or are shutting down).
@@ -377,11 +384,11 @@ TEH_keys_get_timing (const struct TALER_ExchangePublicKeyP *exchange_pub,
 
 
 /**
- * Initialize keys submodule.
+ * Initialize keys subsystem.
  *
  * @return #GNUNET_OK on success
  */
-int
+enum GNUNET_GenericReturnValue
 TEH_keys_init (void);
 
 

src/exchange/taler-exchange-httpd_wire.c

@@ -20,6 +20,7 @@
  */
 #include "platform.h"
 #include <gnunet/gnunet_json_lib.h>
+#include "taler_dbevents.h"
 #include "taler-exchange-httpd_responses.h"
 #include "taler-exchange-httpd_wire.h"
 #include "taler_json_lib.h"
@@ -32,6 +33,11 @@
  */
 static struct WireStateHandle *wire_state;
 
+/**
+ * Handler listening for wire updates by other exchange
+ * services.
+ */
+static struct GNUNET_DB_EventHandler *wire_eh;
 
 /**
  * Counter incremented whenever we have a reason to re-build the #wire_state
@@ -77,6 +83,48 @@ destroy_wire_state (struct WireStateHandle *wsh)
 }
 
 
+/**
+ * Function called whenever another exchange process has updated
+ * the wire data in the database.
+ *
+ * @param cls NULL
+ * @param extra unused
+ * @param extra_size number of bytes in @a extra unused
+ */
+static void
+wire_update_event_cb (void *cls,
+                      const void *extra,
+                      size_t extra_size)
+{
+  (void) cls;
+  (void) extra;
+  (void) extra_size;
+  wire_generation++;
+}
+
+
+int
+TEH_wire_init ()
+{
+  struct GNUNET_DB_EventHeaderP es = {
+    .size = htons (sizeof (es)),
+    .type = htons (TALER_DBEVENT_EXCHANGE_KEYS_UPDATED),
+  };
+
+  wire_eh = TEH_plugin->event_listen (TEH_plugin->cls,
+                                      GNUNET_TIME_UNIT_FOREVER_REL,
+                                      &es,
+                                      &wire_update_event_cb,
+                                      NULL);
+  if (NULL == wire_eh)
+  {
+    GNUNET_break (0);
+    return GNUNET_SYSERR;
+  }
+  return GNUNET_OK;
+}
+
+
 void
 TEH_WIRE_done ()
 {
@@ -85,6 +133,12 @@ TEH_WIRE_done ()
     destroy_wire_state (wire_state);
     wire_state = NULL;
   }
+  if (NULL != wire_eh)
+  {
+    TEH_plugin->event_listen_cancel (TEH_plugin->cls,
+                                     wire_eh);
+    wire_eh = NULL;
+  }
 }
 
 
@@ -302,6 +356,15 @@ build_wire_state (void)
 void
 TEH_wire_update_state (void)
 {
+  struct GNUNET_DB_EventHeaderP es = {
+    .size = htons (sizeof (es)),
+    .type = htons (TALER_DBEVENT_EXCHANGE_WIRE_UPDATED),
+  };
+
+  TEH_plugin->event_notify (TEH_plugin->cls,
+                            &es,
+                            NULL,
+                            0);
   wire_generation++;
 }
 

src/exchange/taler-exchange-httpd_wire.h

@@ -33,6 +33,15 @@ void
 TEH_WIRE_done (void);
 
 
+/**
+ * Initialize wire subsystem.
+ *
+ * @return #GNUNET_OK on success
+ */
+enum GNUNET_GenericReturnValue
+TEH_wire_init (void);
+
+
 /**
  * Something changed in the database. Rebuild the wire replies.  This function
  * should be called if the exchange learns about a new signature from our