Set BCLog::LIBEVENT correctly for old libevent versions.

Backports bitcoin/bitcoin@4d9950d

src/httpserver.cpp

@@ -389,14 +389,13 @@ bool InitHTTPServer()
 
     // Redirect libevent's logging to our own log
     event_set_log_callback(&libevent_log_cb);
-#if LIBEVENT_VERSION_NUMBER >= 0x02010100
-    // If -debug=libevent, set full libevent debugging.
-    // Otherwise, disable all libevent debugging.
-    if (LogAcceptCategory(BCLog::LIBEVENT))
-        event_enable_debug_logging(EVENT_DBG_ALL);
-    else
-        event_enable_debug_logging(EVENT_DBG_NONE);
-#endif
+    // Update libevent's log handling. Returns false if our version of
+    // libevent doesn't support debug logging, in which case we should
+    // clear the BCLog::LIBEVENT flag.
+    if (!UpdateHTTPServerLogging(logCategories & BCLog::LIBEVENT)) {
+        logCategories &= ~BCLog::LIBEVENT;
+    }
+
 #ifdef WIN32
     evthread_use_windows_threads();
 #else
@@ -439,6 +438,20 @@ bool InitHTTPServer()
     return true;
 }
 
+bool UpdateHTTPServerLogging(bool enable) {
+#if LIBEVENT_VERSION_NUMBER >= 0x02010100
+    if (enable) {
+        event_enable_debug_logging(EVENT_DBG_ALL);
+    } else {
+        event_enable_debug_logging(EVENT_DBG_NONE);
+    }
+    return true;
+#else
+    // Can't update libevent logging if version < 02010100
+    return false;
+#endif
+}
+
 std::thread threadHTTP;
 std::future<bool> threadResult;
 

src/httpserver.h

@@ -32,6 +32,10 @@ void InterruptHTTPServer();
 /** Stop HTTP server */
 void StopHTTPServer();
 
+/** Change logging level for libevent. Removes BCLog::LIBEVENT from logCategories if
+ * libevent doesn't support debug logging.*/
+bool UpdateHTTPServerLogging(bool enable);
+
 /** Handler for requests to a certain HTTP path */
 typedef std::function<void(HTTPRequest* req, const std::string &)> HTTPRequestHandler;
 /** Register handler for prefix.