lib-http: client: Fixed handling of stalled connections that emerge when the client...

Inside the peer's request handler routine, the connections are verified
after the ioloop continues. If they turn out to be broken, they
self-destruct while the handler routine is active, leading to problems.

Solved by referencing the connection and retrying the connection statistics
loop when a connection is lost in the process.

diff --git a/src/lib-http/http-client-peer.c b/src/lib-http/http-client-peer.c
index 53aebfcaa5299dca3f2d7927dbcf5b78c1fe0600..ed4e305dd357a6781f71a5e159c9883ef870b115 100644 (file)
--- a/src/lib-http/http-client-peer.c
+++ b/src/lib-http/http-client-peer.c
@@ -275,17 +275,22 @@ http_client_peer_handle_requests_real(struct http_client_peer *peer)
        peer->handling_requests = TRUE;
        t_array_init(&conns_avail, array_count(&peer->conns));
        do {
+               bool conn_lost = FALSE;
+
                array_clear(&conns_avail);
                connecting = closing = idle = 0;
 
                /* gather connection statistics */
                array_foreach(&peer->conns, conn_idx) {
-                       if (http_client_connection_is_ready(*conn_idx)) {                       
+                       struct http_client_connection *conn = *conn_idx;
+
+                       http_client_connection_ref(conn);
+                       if (http_client_connection_is_ready(conn)) {
                                struct _conn_available *conn_avail;
                                unsigned int insert_idx, pending_requests;
 
                                /* compile sorted availability list */
-                               pending_requests = http_client_connection_count_pending(*conn_idx);
+                               pending_requests = http_client_connection_count_pending(conn);
                                if (array_count(&conns_avail) == 0) {
                                        insert_idx = 0;
                                } else {
@@ -298,18 +303,28 @@ http_client_peer_handle_requests_real(struct http_client_peer *peer)
                                        }
                                }
                                conn_avail = array_insert_space(&conns_avail, insert_idx);
-                               conn_avail->conn = *conn_idx;
+                               conn_avail->conn = conn;
                                conn_avail->pending_requests = pending_requests;
                                if (pending_requests == 0)
                                        idle++;
                        }
+                       if (!http_client_connection_unref(&conn)) {
+                               conn_lost = TRUE;
+                               break;
+                       }
+                       conn = *conn_idx;
                        /* count the number of connecting and closing connections */
-                       if ((*conn_idx)->closing)
+                       if (conn->closing)
                                closing++;
-                       else if (!(*conn_idx)->connected)
+                       else if (!conn->connected)
                                connecting++;
                }
 
+               if (conn_lost) {
+                       /* connection array changed while iterating; retry */
+                       continue;
+               }
+
                working_conn_count = array_count(&peer->conns) - closing;
                statistics_dirty = FALSE;