discover/event: Ensure event struct exists for async callers
authorSamuel Mendoza-Jonas <sam@mendozajonas.com>
Thu, 1 Sep 2016 04:32:03 +0000 (14:32 +1000)
committerSamuel Mendoza-Jonas <sam@mendozajonas.com>
Thu, 1 Sep 2016 04:59:05 +0000 (14:59 +1000)
When handling an event, user_event_handle_message() creates an event
struct with relevant parameters. Once user_event_handle_message() is
finished it frees the struct.
However in the case of a dhcp or add_url event, asynchronous jobs may be
spawned that will later reference the event struct. In particular this
becomes a problem when pxe_process_pair() handles an IPAPPEND name/value
pair and tries to access event->device.

In the case of dhcp and add_url events, we avoid this by changing the
event struct's talloc parent to the discover_context struct which
persists until all async pxe jobs have completed.

Signed-off-by: Samuel Mendoza-Jonas <sam@mendozajonas.com>
discover/device-handler.c
discover/user-event.c

index f6b6d22ed6a2f6f713b7f0d703b42e72901c01d9..346cb0221d7f08e8b5bcbd7b72f33c596f344f8b 100644 (file)
@@ -900,6 +900,7 @@ int device_handler_dhcp(struct device_handler *handler,
 
        /* create our context */
        ctx = device_handler_discover_context_create(handler, dev);
+       talloc_steal(ctx, event);
        ctx->event = event;
 
        iterate_parsers(ctx);
@@ -1171,6 +1172,7 @@ void device_handler_process_url(struct device_handler *handler,
        if (pb_url->scheme == pb_url_file)
                dev->device->type = DEVICE_TYPE_ANY;
        ctx = device_handler_discover_context_create(handler, dev);
+       talloc_steal(ctx, event);
        ctx->event = event;
 
        iterate_parsers(ctx);
index 6ea754fea808de474368b887a43278aef8248fbb..3ccac90660b2e635786efe0a875b97da80d20325 100644 (file)
@@ -513,13 +513,13 @@ static void user_event_handle_message(struct user_event *uev, char *buf,
                break;
        case EVENT_ACTION_URL:
                result = user_event_url(uev, event);
-               break;
+               goto out;
        case EVENT_ACTION_CONF:
                result = user_event_conf(uev, event);
                break;
        case EVENT_ACTION_DHCP:
                result = user_event_dhcp(uev, event);
-               break;
+               goto out;
        case EVENT_ACTION_BOOT:
                result = user_event_boot(uev, event);
                break;
@@ -530,8 +530,10 @@ static void user_event_handle_message(struct user_event *uev, char *buf,
                break;
        }
 
+       /* user_event_url() and user_event_dhcp() will steal the event context,
+        * but all others still need to free */
        talloc_free(event);
-
+out:
        return;
 }