libCom: Replaced errlogRemoveListener()

New version errlogRemoveListeners() is safer.

documentation/RELEASE_NOTES.html

@@ -15,6 +15,16 @@ EPICS Base 3.15.0.x releases are not intended for use in production systems.</p>
 <h2 align="center">Changes between 3.15.0.1 and 3.15.0.2</h2>
 <!-- Insert new items immediately below here ... -->
 
+<h3>errlogRemoveListener() routine changed</h3>
+
+<p>Code that calls <tt>errlogRemoveListener(myfunc)</tt> must be modified to use
+the new, safer routine <tt>errlogRemoveListeners(myfunc, &amp;pvt)</tt> instead.
+The replacement routine takes a second argument which must be the same private
+pointer that was passed to <tt>errlogAddListener()</tt> when adding that
+listener. It also deletes all matching listeners (hence the new plural name) and
+returns how many were actually deleted, whereas the previous routine only
+removed the first listener that matched.</p>
+
 <h3>Simplified generation of .dbd files</h3>
 
 <p>The Perl script <tt>makeIncludeDbd.pl</tt> has been removed and the rules

src/libCom/error/errlog.c

@@ -331,11 +331,12 @@ epicsShareFunc void epicsShareAPI errlogAddListener(
     ellAdd(&pvtData.listenerList,&plistenerNode->node);
     epicsMutexUnlock(pvtData.listenerLock);
 }
-    
-epicsShareFunc void epicsShareAPI errlogRemoveListener(
-    errlogListener listener)
+
+epicsShareFunc int epicsShareAPI errlogRemoveListeners(
+    errlogListener listener, void *pPrivate)
 {
     listenerNode *plistenerNode;
+    int count = 0;
 
     errlogInit(0);
     if (!pvtData.atExit)
@@ -343,21 +344,25 @@ epicsShareFunc void epicsShareAPI errlogRemoveListener(
 
     plistenerNode = (listenerNode *)ellFirst(&pvtData.listenerList);
     while (plistenerNode) {
-        if (plistenerNode->listener==listener) {
+        listenerNode *pnext = (listenerNode *)ellNext(&plistenerNode->node);
+
+        if (plistenerNode->listener == listener &&
+            plistenerNode->pPrivate == pPrivate) {
             ellDelete(&pvtData.listenerList, &plistenerNode->node);
-            free((void *)plistenerNode);
-            break;
+            free(plistenerNode);
+            ++count;
         }
-        plistenerNode = (listenerNode *)ellNext(&plistenerNode->node);
+        plistenerNode = pnext;
     }
 
     if (!pvtData.atExit)
         epicsMutexUnlock(pvtData.listenerLock);
 
-    if (!plistenerNode) {
+    if (count == 0) {
         fprintf(pvtData.console,
-            "errlogRemoveListener did not find listener\n");
+            "errlogRemoveListeners: No listeners found\n");
     }
+    return count;
 }
 
 epicsShareFunc int epicsShareAPI eltc(int yesno)

src/libCom/error/errlog.h

@@ -57,8 +57,8 @@ epicsShareFunc errlogSevEnum epicsShareAPI errlogGetSevToLog(void);
 
 epicsShareFunc void epicsShareAPI errlogAddListener(
     errlogListener listener, void *pPrivate);
-epicsShareFunc void epicsShareAPI errlogRemoveListener(
-    errlogListener listener);
+epicsShareFunc int epicsShareAPI errlogRemoveListeners(
+    errlogListener listener, void *pPrivate);
 
 epicsShareFunc int epicsShareAPI eltc(int yesno);
 epicsShareFunc int errlogSetConsole(FILE *stream);

src/libCom/test/epicsErrlogTest.c

@@ -142,7 +142,7 @@ MAIN(epicsErrlogTest)
     char msg[256];
     clientPvt pvt, pvt2;
 
-    testPlan(29);
+    testPlan(32);
 
     strcpy(msg, truncmsg);
 
@@ -186,8 +186,9 @@ MAIN(epicsErrlogTest)
     testOk1(pvt.count == 2);
     testOk1(pvt2.count == 1);
 
-    /* Removes the first listener, but the second remains */
-    errlogRemoveListener(&logClient);
+    /* Removes the first listener */
+    testOk(1 == errlogRemoveListeners(&logClient, &pvt),
+        "Removed 1 listener");
 
     pvt2.expect = "Testing3";
     pvt2.checkLen = strlen(pvt2.expect);
@@ -198,8 +199,10 @@ MAIN(epicsErrlogTest)
     testOk1(pvt.count == 2);
     testOk1(pvt2.count == 2);
 
-    /* Remove the second listener */
-    errlogRemoveListener(&logClient);
+    /* Add the second listener again, then remove both instances */
+    errlogAddListener(&logClient, &pvt2);
+    testOk(2 == errlogRemoveListeners(&logClient, &pvt2),
+        "Removed 2 listeners");
 
     errlogPrintfNoConsole("Something different");
     errlogFlush();
@@ -314,7 +317,8 @@ MAIN(epicsErrlogTest)
     testOk1(pvt.count == N+1);
 
     /* Clean up */
-    errlogRemoveListener(&logClient);
+    testOk(1 == errlogRemoveListeners(&logClient, &pvt),
+        "Removed 1 listener");
 
     testLogPrefix();