From b8419ec17dad02a5f096233739875d3f6e483c25 Mon Sep 17 00:00:00 2001
From: Dirk Zimoch <dirk.zimoch@psi.ch>
Date: Wed, 4 Sep 2019 10:27:10 +0200
Subject: [PATCH] don't reconnect to log server unnecessarily

---
 src/libCom/logClient/logClient.c | 55 ++++++++++++++++++++------------
 1 file changed, 34 insertions(+), 21 deletions(-)

diff --git a/src/libCom/logClient/logClient.c b/src/libCom/logClient/logClient.c
index 0056a21fe..692ac3105 100644
--- a/src/libCom/logClient/logClient.c
+++ b/src/libCom/logClient/logClient.c
@@ -25,7 +25,6 @@
 #include "dbDefs.h"
 #include "epicsEvent.h"
 #include "iocLog.h"
-#include "errlog.h"
 #include "epicsMutex.h"
 #include "epicsThread.h"
 #include "epicsTime.h"
@@ -162,6 +161,31 @@ static void logClientDestroy (logClientId id)
     free ( pClient );
 }
 
+/*
+ * logClientCheckConnection
+ */
+static void logClientCheckConnection( logClient * pClient )
+{
+    epicsMutexMustLock ( pClient->mutex );
+    while ( pClient->connected ) {
+        struct timeval timeout = { 0, 0 };
+        fd_set set;
+        char buffer[256];
+
+        FD_ZERO ( &set );
+        FD_SET ( pClient->sock, &set );
+        if ( select ( pClient->sock + 1, &set, NULL, NULL, &timeout ) == 0)
+            break;
+        if ( recv ( pClient->sock, buffer, sizeof ( buffer ), 0 ) == 0 ) {
+            fprintf ( stderr, "log client: connection closed by server \"%s\"\n",
+                pClient->name );
+            logClientClose ( pClient );
+            break;
+        }
+    }
+    epicsMutexUnlock ( pClient->mutex );
+}
+
 /*
  * This method requires the pClient->mutex be owned already.
  */
@@ -176,6 +200,7 @@ static void sendMessageChunk(logClient * pClient, const char * message) {
         if ( msgBufBytesLeft < strSize && pClient->nextMsgIndex != 0u && pClient->connected)
         {
             /* buffer is full, thus flush it */
+            logClientCheckConnection( pClient );
             logClientFlush ( pClient );
             msgBufBytesLeft = sizeof ( pClient->msgBuf ) - pClient->nextMsgIndex;
         }
@@ -228,23 +253,6 @@ void epicsShareAPI logClientFlush ( logClientId id )
 
     epicsMutexMustLock ( pClient->mutex );
 
-    while (1) {
-        struct timeval timeout = { 0, 0 };
-        fd_set set;
-        char buffer[256];
-
-        FD_ZERO ( &set );
-        FD_SET ( pClient->sock, &set );
-        if ( select ( pClient->sock + 1, &set, NULL, NULL, &timeout ) == 0)
-            break;
-        if ( recv ( pClient->sock, buffer, sizeof ( buffer ), 0 ) == 0 ) {
-            fprintf ( stderr, "log client: connection closed by server \"%s\"\n",
-                pClient->name );
-            logClientClose ( pClient );
-            break;
-        }
-    }
-
     while ( nSent < pClient->nextMsgIndex && pClient->connected ) {
         int status = send ( pClient->sock, pClient->msgBuf + nSent,
             pClient->nextMsgIndex - nSent, 0 );
@@ -415,14 +423,19 @@ static void logClientRestart ( logClientId id )
     /* SMP safe state inspection */
     epicsMutexMustLock ( pClient->mutex );
     while ( ! pClient->shutdown ) {
-        unsigned isConn;
+        unsigned isConn, dataToSend;
+
+        logClientCheckConnection( pClient );
 
         isConn = pClient->connected;
+        dataToSend = pClient->nextMsgIndex;
 
         epicsMutexUnlock ( pClient->mutex );
 
-        if ( ! isConn ) logClientConnect ( pClient );
-        logClientFlush ( pClient );
+        if ( dataToSend ) {
+            if ( ! isConn ) logClientConnect ( pClient );
+            logClientFlush ( pClient );
+        }
 
         epicsEventWaitWithTimeout ( pClient->shutdownNotify, LOG_RESTART_DELAY);