CLEANUP: resolvers: replace all LIST_DELETE with LIST_DEL_INIT

The code as it is uses crossed lists between many elements, and at
many places the code relies on list iterators or emptiness checks,
which does not work with only LIST_DELETE. Further, it is quite
difficult to place debugging code and checks in the current situation,
and gdb is helpless.

This code replaces all LIST_DELETE calls with LIST_DEL_INIT so that
it becomes possible to trust the lists.

(cherry picked from commit aae7320b0dd9a379792d7cbe3304b23bdb045740)
Signed-off-by: Willy Tarreau <w@1wt.eu>
(cherry picked from commit 8c3c523097988005ee69128ace10bcc16c81398b)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>

diff --git a/src/dns.c b/src/dns.c
index 32943c3..7ce4d32 100644 (file)
--- a/src/dns.c
+++ b/src/dns.c
@@ -439,7 +439,7 @@ static int dns_send_query(struct dns_resolution *resolution)
        }
 
        /* Push the resolution at the end of the active list */
-       LIST_DEL(&resolution->list);
+       LIST_DEL_INIT(&resolution->list);
        LIST_ADDQ(&resolvers->resolutions.curr, &resolution->list);
        return 0;
 }
@@ -652,7 +652,7 @@ static void dns_srvrq_cleanup_srv(struct server *srv, int safe)
        srv->host_dn.key = NULL;
 
        HA_SPIN_UNLOCK(SERVER_LOCK, &srv->lock);
-       LIST_DEL(&srv->srv_rec_item);
+       LIST_DEL_INIT(&srv->srv_rec_item);
        LIST_ADDQ(&srv->srvrq->attached_servers, &srv->srv_rec_item);
 
        srv->srvrq_check->expire = TICK_ETERNITY;
@@ -713,7 +713,7 @@ static void dns_check_dns_response(struct dns_resolution *res)
                                        dns_srvrq_cleanup_srv(srv, 0);
                        }
 
-                       LIST_DEL(&item->list);
+                       LIST_DEL_INIT(&item->list);
                        if (item->ar_item) {
                                pool_free(dns_answer_item_pool, item->ar_item);
                                item->ar_item = NULL;
@@ -1680,7 +1680,7 @@ int dns_get_ip_from_response(struct dns_response_packet *dns_p,
        list_for_each_entry(record, &dns_p->answer_list, list) {
                /* Move the first record to the end of the list, for internal
                 * round robin */
-               LIST_DEL(&record->list);
+               LIST_DEL_INIT(&record->list);
                LIST_ADDQ(&dns_p->answer_list, &record->list);
                break;
        }
@@ -1884,7 +1884,7 @@ static void dns_purge_resolution_answer_records(struct dns_resolution *resolutio
        struct dns_answer_item *item, *itemback;
 
        list_for_each_entry_safe(item, itemback, &resolution->response.answer_list, list) {
-               LIST_DEL(&item->list);
+               LIST_DEL_INIT(&item->list);
                pool_free(dns_answer_item_pool, item->ar_item);
                pool_free(dns_answer_item_pool, item);
        }
@@ -1912,11 +1912,11 @@ static void dns_free_resolution(struct dns_resolution *resolution)
        resolution->hostname_dn_len = 0;
 
        list_for_each_entry_safe(req, reqback, &resolution->requesters, list) {
-               LIST_DEL(&req->list);
+               LIST_DEL_INIT(&req->list);
                req->resolution = NULL;
        }
        dns_purge_resolution_answer_records(resolution);
-       LIST_DEL(&resolution->list);
+       LIST_DEL_INIT(&resolution->list);
        pool_free(dns_resolution_pool, resolution);
 }
 
@@ -2085,7 +2085,7 @@ void dns_unlink_resolution(struct dns_requester *requester, int safe)
        dns_detach_from_resolution_answer_items(res,  requester, safe);
 
        /* Clean up the requester */
-       LIST_DEL(&requester->list);
+       LIST_DEL_INIT(&requester->list);
        requester->resolution = NULL;
 
        /* We need to find another requester linked on this resolution */
@@ -2310,7 +2310,7 @@ static void dns_resolve_recv(struct dgram_conn *dgram)
                if (!keep_answer_items)
                        dns_purge_resolution_answer_records(res);
                dns_reset_resolution(res);
-               LIST_DEL(&res->list);
+               LIST_DEL_INIT(&res->list);
                LIST_ADDQ(&resolvers->resolutions.wait, &res->list);
                continue;
 
@@ -2330,7 +2330,7 @@ static void dns_resolve_recv(struct dgram_conn *dgram)
                }
 
                dns_reset_resolution(res);
-               LIST_DEL(&res->list);
+               LIST_DEL_INIT(&res->list);
                LIST_ADDQ(&resolvers->resolutions.wait, &res->list);
                continue;
        }
@@ -2454,7 +2454,7 @@ static struct task *dns_process_resolvers(struct task *t, void *context, unsigne
                        /* Clean up resolution info and remove it from the
                         * current list */
                        dns_reset_resolution(res);
-                       LIST_DEL(&res->list);
+                       LIST_DEL_INIT(&res->list);
                        LIST_ADDQ(&resolvers->resolutions.wait, &res->list);
                }
                else {
@@ -2492,7 +2492,7 @@ static struct task *dns_process_resolvers(struct task *t, void *context, unsigne
 
                if (dns_run_resolution(res) != 1) {
                        res->last_resolution = now_ms;
-                       LIST_DEL(&res->list);
+                       LIST_DEL_INIT(&res->list);
                        LIST_ADDQ(&resolvers->resolutions.wait, &res->list);
                }
        }
@@ -2524,14 +2524,14 @@ static void dns_deinit(void)
                        if (ns->dgram && ns->dgram->t.sock.fd != -1)
                                fd_delete(ns->dgram->t.sock.fd);
                        free(ns->dgram);
-                       LIST_DEL(&ns->list);
+                       LIST_DEL_INIT(&ns->list);
                        EXTRA_COUNTERS_FREE(ns->extra_counters);
                        free(ns);
                }
 
                list_for_each_entry_safe(res, resback, &resolvers->resolutions.curr, list) {
                        list_for_each_entry_safe(req, reqback, &res->requesters, list) {
-                               LIST_DEL(&req->list);
+                               LIST_DEL_INIT(&req->list);
                                pool_free(dns_requester_pool, req);
                        }
                        dns_free_resolution(res);
@@ -2539,7 +2539,7 @@ static void dns_deinit(void)
 
                list_for_each_entry_safe(res, resback, &resolvers->resolutions.wait, list) {
                        list_for_each_entry_safe(req, reqback, &res->requesters, list) {
-                               LIST_DEL(&req->list);
+                               LIST_DEL_INIT(&req->list);
                                pool_free(dns_requester_pool, req);
                        }
                        dns_free_resolution(res);
@@ -2548,14 +2548,14 @@ static void dns_deinit(void)
                free(resolvers->id);
                free((char *)resolvers->conf.file);
                task_destroy(resolvers->t);
-               LIST_DEL(&resolvers->list);
+               LIST_DEL_INIT(&resolvers->list);
                free(resolvers);
        }
 
        list_for_each_entry_safe(srvrq, srvrqback, &dns_srvrq_list, list) {
                free(srvrq->name);
                free(srvrq->hostname_dn);
-               LIST_DEL(&srvrq->list);
+               LIST_DEL_INIT(&srvrq->list);
                free(srvrq);
        }
 }