pullup:

It was possible to join to an already running fctx
after it had "cloned" its events, but before it sent
them.  In this case, the event of the newly joined
fetch would not contain the answer, and would
trigger the INSIST() in fctx_sendevents().
[RT #597, #605, #607]

diff --git a/lib/dns/resolver.c b/lib/dns/resolver.c
index 75308b4e7d9830a8519f28b1382249ec33e5f874..f52b6ea9da28ac2dde78879663872b57ca2bd750 100644 (file)
--- a/lib/dns/resolver.c
+++ b/lib/dns/resolver.c
@@ -15,7 +15,7 @@
  * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: resolver.c,v 1.187 2000/12/20 23:18:37 gson Exp $ */
+/* $Id: resolver.c,v 1.187.2.1 2001/01/05 22:06:19 gson Exp $ */
 
 #include <config.h>
 
@@ -152,6 +152,7 @@ struct fetchctx {
        /* Locked by appropriate bucket lock. */
        fetchstate                      state;
        isc_boolean_t                   want_shutdown;
+       isc_boolean_t                   cloned;
        unsigned int                    references;
        isc_event_t                     control_event;
        ISC_LINK(struct fetchctx)       link;
@@ -2048,6 +2049,7 @@ fctx_create(dns_resolver_t *res, dns_name_t *name, dns_rdatatype_t type,
        fctx->bucketnum = bucketnum;
        fctx->state = fetchstate_init;
        fctx->want_shutdown = ISC_FALSE;
+       fctx->cloned = ISC_FALSE;
        ISC_LIST_INIT(fctx->queries);
        ISC_LIST_INIT(fctx->finds);
        ISC_LIST_INIT(fctx->forwaddrs);
@@ -2302,6 +2304,7 @@ clone_results(fetchctx_t *fctx) {
         * Caller must be holding the appropriate lock.
         */
 
+       fctx->cloned = ISC_TRUE;
        hevent = ISC_LIST_HEAD(fctx->events);
        if (hevent == NULL)
                return;
@@ -4867,7 +4870,16 @@ dns_resolver_createfetch(dns_resolver_t *res, dns_name_t *name,
                }
        }
 
-       if (fctx == NULL || fctx->state == fetchstate_done) {
+       /*
+        * If we didn't have a fetch, would attach to a done fetch, this
+        * fetch has already cloned its results, or if the fetch has gone
+        * "idle" (no one was interested in it), we need to start a new
+        * fetch instead of joining with the existing one.
+        */
+       if (fctx == NULL ||
+           fctx->state == fetchstate_done ||
+           fctx->cloned ||
+           ISC_LIST_EMPTY(fctx->events)) {
                fctx = NULL;
                result = fctx_create(res, name, type, domain, nameservers,
                                     options, bucketnum, &fctx);
@@ -4875,6 +4887,7 @@ dns_resolver_createfetch(dns_resolver_t *res, dns_name_t *name,
                        goto unlock;
                new_fctx = ISC_TRUE;
        }
+
        result = fctx_join(fctx, task, action, arg,
                           rdataset, sigrdataset, fetch);
        if (new_fctx) {