add grace period for race in connection cleanup

src/ebusd/network.cpp

@@ -187,6 +187,7 @@ void Connection::run() {
     delete m_socket;
     m_socket = nullptr;
   }
+  time(&m_endedAt);
   logInfo(lf_network, "[%05d] connection closed", getID());
 }
 
@@ -339,9 +340,12 @@ void Network::run() {
 
 void Network::cleanConnections() {
   auto it = m_connections.begin();
+  time_t endBefore;
+  time(&endBefore);
+  endBefore += 5;  // after 5 seconds grace period
   while (it != m_connections.end()) {
-    if (!(*it)->isRunning()) {
     Connection* connection = *it;
+    if (connection && !connection->isRunning() && connection->endedBefore(&endBefore)) {
       it = m_connections.erase(it);
       delete connection;
       logDebug(lf_network, "dead connection removed - %d", m_connections.size());

src/ebusd/network.h

@@ -227,7 +227,7 @@ class Connection : public Thread {
    * @param netQueue the reference to the @a NetMessage @a Queue.
    */
   Connection(TCPSocket* socket, const bool isHttp, Queue<NetMessage*>* netQueue)
-    : Thread(), m_isHttp(isHttp), m_socket(socket), m_netQueue(netQueue) {
+    : Thread(), m_isHttp(isHttp), m_socket(socket), m_netQueue(netQueue), m_endedAt(0) {
     m_id = ++m_ids;
   }
 
@@ -253,6 +253,12 @@ class Connection : public Thread {
    */
   int getID() { return m_id; }
 
+  /**
+   * Return whether this connection has ended before the specified time.
+   * @param time the time to check against.
+   * @return true when this connection has ended before the specified time.
+   */
+  bool endedBefore(const time_t* time) const { return m_endedAt > 0 && time && m_endedAt < *time; }
 
  private:
   /** whether this is a HTTP connection. */
@@ -270,6 +276,9 @@ class Connection : public Thread {
   /** the ID of this connection. */
   int m_id;
 
+  /** the time when this connected ended, or 0 if not yet. */
+  time_t m_endedAt;
+
   /** the IF of the last opened connection. */
   static int m_ids;
 };