From d2b0e920012d4c9bc0eaecc0e092cedd776db578 Mon Sep 17 00:00:00 2001
From: Michael Davidsaver <mdavidsaver@bnl.gov>
Date: Fri, 29 Jun 2012 17:02:23 -0400
Subject: [PATCH] db_close_events cleanup

Move cleanup from event thread to caller.
This handles cases (unit tests) where the task
is never started.

The pexitsem flag serves as the indicatior that
the event task was started.
---
 src/ioc/db/dbEvent.c | 78 ++++++++++++++++++++++++++++----------------
 1 file changed, 50 insertions(+), 28 deletions(-)

diff --git a/src/ioc/db/dbEvent.c b/src/ioc/db/dbEvent.c
index 8b6cb06c3..24d81a04a 100644
--- a/src/ioc/db/dbEvent.c
+++ b/src/ioc/db/dbEvent.c
@@ -74,6 +74,7 @@ struct event_user {
     epicsMutexId        lock;
     epicsEventId        ppendsem;       /* Wait while empty */
     epicsEventId        pflush_sem;     /* wait for flush */
+    epicsEventId        pexitsem;       /* wait for event task to join */
 
     EXTRALABORFUNC      *extralabor_sub;/* off load to event task */
     void                *extralabor_arg;/* parameter to above */
@@ -276,35 +277,44 @@ dbEventCtx epicsShareAPI db_init_events (void)
         return NULL;
     }
 
+    /* Flag will be cleared when event task starts */
+    evUser->pendexit = TRUE;
+
     evUser->firstque.evUser = evUser;
     evUser->firstque.writelock = epicsMutexCreate();
-    if (!evUser->firstque.writelock) {
-        return NULL;
-    }
+    if (!evUser->firstque.writelock)
+        goto fail;
 
     evUser->ppendsem = epicsEventCreate(epicsEventEmpty);
-    if (!evUser->ppendsem) {
-        epicsMutexDestroy (evUser->firstque.writelock);
-        return NULL;
-    }
+    if (!evUser->ppendsem)
+        goto fail;
     evUser->pflush_sem = epicsEventCreate(epicsEventEmpty);
-    if (!evUser->pflush_sem) {
-        epicsMutexDestroy (evUser->firstque.writelock);
-        epicsEventDestroy (evUser->ppendsem);
-        return NULL;
-    }
+    if (!evUser->pflush_sem)
+        goto fail;
     evUser->lock = epicsMutexCreate();
-    if (!evUser->lock) {
-        epicsMutexDestroy (evUser->firstque.writelock);
-        epicsEventDestroy (evUser->pflush_sem);
-        epicsEventDestroy (evUser->ppendsem);
-        return NULL;
-    }
+    if (!evUser->lock)
+        goto fail;
+    evUser->pexitsem = epicsEventCreate(epicsEventEmpty);
+    if (!evUser->pexitsem)
+        goto fail;
 
     evUser->flowCtrlMode = FALSE;
     evUser->extraLaborBusy = FALSE;
     evUser->pSuicideEvent = NULL;
     return (dbEventCtx) evUser;
+fail:
+    if(evUser->lock)
+        epicsMutexDestroy (evUser->lock);
+    if(evUser->firstque.writelock)
+        epicsMutexDestroy (evUser->firstque.writelock);
+    if(evUser->ppendsem)
+        epicsEventDestroy (evUser->ppendsem);
+    if(evUser->pflush_sem)
+        epicsEventDestroy (evUser->pflush_sem);
+    if(evUser->pexitsem)
+        epicsEventDestroy (evUser->pexitsem);
+    freeListFree(dbevEventUserFreeList,evUser);
+    return NULL;
 }
 
 /*
@@ -328,10 +338,26 @@ void epicsShareAPI db_close_events (dbEventCtx ctx)
      * hazardous to the system's health.
      */
     epicsMutexMustLock ( evUser->lock );
-    evUser->pendexit = TRUE;
+    if(!evUser->pendexit) { /* event task running */
+        evUser->pendexit = TRUE;
+        epicsMutexUnlock ( evUser->lock );
+
+        /* notify the waiting task */
+        epicsEventSignal(evUser->ppendsem);
+        /* wait for task to exit */
+        epicsEventMustWait(evUser->pexitsem);
+
+        epicsMutexMustLock ( evUser->lock );
+    }
+
     epicsMutexUnlock ( evUser->lock );
-    /* notify the waiting task */
-    epicsEventSignal(evUser->ppendsem);
+
+    epicsEventDestroy(evUser->pexitsem);
+    epicsEventDestroy(evUser->ppendsem);
+    epicsEventDestroy(evUser->pflush_sem);
+    epicsMutexDestroy(evUser->lock);
+
+    freeListFree(dbevEventUserFreeList, evUser);
 }
 
 /*
@@ -1006,14 +1032,10 @@ static void event_task (void *pParm)
         }
     }
 
-    epicsEventDestroy(evUser->ppendsem);
-    epicsEventDestroy(evUser->pflush_sem);
-    epicsMutexDestroy(evUser->lock);
-
-    freeListFree(dbevEventUserFreeList, evUser);
-
     taskwdRemove(epicsThreadGetIdSelf());
 
+    epicsEventSignal(evUser->pexitsem);
+
     return;
 }
 
@@ -1037,7 +1059,6 @@ int epicsShareAPI db_start_events (
          return DB_EVENT_OK;
      }
 
-     evUser->pendexit = FALSE;
      evUser->init_func = init_func;
      evUser->init_func_arg = init_func_arg;
      if (!taskname) {
@@ -1051,6 +1072,7 @@ int epicsShareAPI db_start_events (
          epicsMutexUnlock ( evUser->lock );
          return DB_EVENT_ERROR;
      }
+     evUser->pendexit = FALSE;
      epicsMutexUnlock ( evUser->lock );
      return DB_EVENT_OK;
 }