<div dir="ltr"><div class="gmail_extra"> <div class="gmail_quote">On Thu, May 23, 2013 at 3:20 PM, <<a href="mailto:alexl@redhat.com" target="_blank">alexl@redhat.com</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> From: Alexander Larsson <<a href="mailto:alexl@redhat.com">alexl@redhat.com</a>> If an interface has any messages and its version is larger than 1 then we emit a method counts array which lists the number of methods for each version of the interface. This can be used in addition to the normal method_count to reject requests that the server doesn't support. This allows the wayland server library to be upgraded and still safely run oler compositors that don't implement the new requests. Since there is no other space in the wm_interface we add the method count array at the end of the events array. We then add some warnings to the event sending code so that we never accidentally trigger these events. </blockquote><div> </div><div>Would it possibly be better to use the upper bits of method_count (or method_count < 0) to signal that a method_counts array is appended to methods? This keeps methods with methods and also allows us to optionally do the same thing with events client-side to protect clients from broken newer-version compositors. </div><div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> Then we add code in the server to reject messages that are not supported by the server version of the object they are sent to. --- src/scanner.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++------ src/wayland-server.c | 34 +++++++++++++++++++++++++++++++-- 2 files changed, 80 insertions(+), 8 deletions(-) diff --git a/src/scanner.c b/src/scanner.c index 9c14ad3..38e7909 100644 --- a/src/scanner.c +++ b/src/scanner.c @@ -1019,12 +1019,13 @@ emit_types(struct protocol *protocol, struct wl_list *message_list) static void emit_messages(struct wl_list *message_list, - struct interface *interface, const char *suffix) + struct interface *interface, const char *suffix, + int emit_method_counts) { struct message *m; struct arg *a; - if (wl_list_empty(message_list)) + if (wl_list_empty(message_list) && !emit_method_counts) return; printf("static const struct wl_message " @@ -1070,13 +1071,52 @@ emit_messages(struct wl_list *message_list, printf("\", types + %d },\n", m->type_index); } + if (emit_method_counts) { + printf("\t{ NULL, \"\", (void *)%s_method_counts },\n", interface->name); + } + + printf("};\n\n"); +} + +static int +emit_method_counts(struct wl_list *message_list, + struct interface *interface) +{ + struct message *m; + int version = 1; + int count; + + if (wl_list_empty(message_list) || interface->version == 1) + return 0; + + printf("static const uint32_t " + "%s_method_counts[] = { ", + interface->name); + + count = 0; + wl_list_for_each(m, message_list, link) { + while (m->since != version) { + printf("%d,", count); + version++; + } + count++; + } + + while (version <= interface->version) { + printf("%d, ", count); + version++; + } + printf("};\n\n"); + + return 1; } static void emit_code(struct protocol *protocol) { struct interface *i; + int has_method_counts; if (protocol->copyright) format_copyright(protocol->copyright); @@ -1101,8 +1141,10 @@ emit_code(struct protocol *protocol) wl_list_for_each(i, &protocol->interface_list, link) { - emit_messages(&i->request_list, i, "requests"); - emit_messages(&i->event_list, i, "events"); + + emit_messages(&i->request_list, i, "requests", 0); + has_method_counts = emit_method_counts(&i->request_list, i); + emit_messages(&i->event_list, i, "events", has_method_counts); printf("WL_EXPORT const struct wl_interface " "%s_interface = {\n" @@ -1115,9 +1157,9 @@ emit_code(struct protocol *protocol) else printf("\t0, NULL,\n"); - if (!wl_list_empty(&i->event_list)) + if (!wl_list_empty(&i->event_list) || has_method_counts) printf("\t%d, %s_events,\n", - wl_list_length(&i->event_list), i->name); + wl_list_length(&i->event_list) + has_method_counts, i->name); else printf("\t0, NULL,\n"); diff --git a/src/wayland-server.c b/src/wayland-server.c index c808f6a..e94366b 100644 --- a/src/wayland-server.c +++ b/src/wayland-server.c @@ -124,6 +124,12 @@ wl_resource_post_event(struct wl_resource *resource, uint32_t opcode, ...) struct wl_object *object = &resource->object; va_list ap; + if (opcode >= (uint32_t)object->interface->event_count || + object->interface->events[opcode].name == NULL) { + wl_log ("Trying to post unsupported event\n"); + return; + } + va_start(ap, opcode); closure = wl_closure_vmarshal(object, opcode, ap, &object->interface->events[opcode]); @@ -150,6 +156,12 @@ wl_resource_queue_event(struct wl_resource *resource, uint32_t opcode, ...) struct wl_object *object = &resource->object; va_list ap; + if (opcode >= (uint32_t)object->interface->event_count || + object->interface->events[opcode].name == NULL) { + wl_log ("Trying to queue unsupported event\n"); + return; + } + va_start(ap, opcode); closure = wl_closure_vmarshal(object, opcode, ap, &object->interface->events[opcode]); @@ -206,7 +218,8 @@ wl_client_connection_data(int fd, uint32_t mask, void *data) struct wl_closure *closure; const struct wl_message *message; uint32_t p[2]; - int opcode, size; + uint32_t opcode; + int size; int len; if (mask & (WL_EVENT_ERROR | WL_EVENT_HANGUP)) { @@ -250,7 +263,7 @@ wl_client_connection_data(int fd, uint32_t mask, void *data) } object = &resource->object; - if (opcode >= object->interface->method_count) { + if (opcode >= (uint32_t)object->interface->method_count) { wl_resource_post_error(client->display_resource, WL_DISPLAY_ERROR_INVALID_METHOD, "invalid method %d, object %s@%u", @@ -260,6 +273,23 @@ wl_client_connection_data(int fd, uint32_t mask, void *data) break; } + if (object->interface->event_count > 0 && + object->interface->events[object->interface->event_count-1].name == NULL) { + uint32_t *method_counts = (uint32_t *) + object->interface->events[object->interface->event_count-1].types; + + if (opcode >= method_counts[wl_resource_get_version (resource)]) { + wl_resource_post_error(client->display_resource, + WL_DISPLAY_ERROR_INVALID_METHOD, + "invalid method %d, object %s@%u", + opcode, + object->interface->name, + object->id); + break; + } + } + + message = &object->interface->methods[opcode]; closure = wl_connection_demarshal(client->connection, size, &client->objects, message); -- 1.8.1.4 _______________________________________________ wayland-devel mailing list <a href="mailto:wayland-devel@lists.freedesktop.org">wayland-devel@lists.freedesktop.org</a> <a href="http://lists.freedesktop.org/mailman/listinfo/wayland-devel" target="_blank">http://lists.freedesktop.org/mailman/listinfo/wayland-devel</a> </blockquote></div> </div><div class="gmail_extra">Thanks, </div><div class="gmail_extra">--Jason Ekstrand </div></div>