X-Git-Url: https://git.lttng.org/?a=blobdiff_plain;f=src%2Fbin%2Flttng-sessiond%2Fust-app.cpp;h=11d604ea9a463e7c32126b5189e46707e74f7ce1;hb=b6bbb1d666531bf061f29884da1b0d7c10f59aa0;hp=88db75f8f4d7da8f1f2ae5cc3d7978cae26fafdd;hpb=6d31b87d46a9301fe86d273616ab3d7214d24e65;p=lttng-tools.git

diff --git a/src/bin/lttng-sessiond/ust-app.cpp b/src/bin/lttng-sessiond/ust-app.cpp
index 88db75f8f..11d604ea9 100644
--- a/src/bin/lttng-sessiond/ust-app.cpp
+++ b/src/bin/lttng-sessiond/ust-app.cpp
@@ -6426,23 +6426,49 @@ static int handle_app_register_channel_notification(int sock,
 	 * that all apps provide the same typing for the context fields as a
 	 * sanity check.
 	 */
-	lst::type::cuptr context_fields = lttng::make_unique<lst::structure_type>(0,
-			lsu::create_trace_fields_from_ust_ctl_fields(*locked_registry_session,
-					ust_ctl_context_fields.get(), context_field_count));
+	try {
+		auto app_context_fields = lsu::create_trace_fields_from_ust_ctl_fields(
+				*locked_registry_session, ust_ctl_context_fields.get(),
+				context_field_count,
+				lst::field_location::root::EVENT_RECORD_COMMON_CONTEXT,
+				lsu::ctl_field_quirks::UNDERSCORE_PREFIXED_VARIANT_TAG_MAPPINGS);
+
+		if (!ust_reg_chan.is_registered()) {
+			lst::type::cuptr event_context = app_context_fields.size() ?
+					lttng::make_unique<lst::structure_type>(
+							0, std::move(app_context_fields)) :
+					nullptr;
+
+			ust_reg_chan.set_event_context(std::move(event_context));
+		} else {
+			/*
+			 * Validate that the context fields match between
+			 * registry and newcoming application.
+			 */
+			bool context_fields_match;
+			const auto *previous_event_context = ust_reg_chan.get_event_context();
 
-	if (!ust_reg_chan.is_registered()) {
-		ust_reg_chan.set_context(std::move(context_fields));
-	} else {
-		/*
-		 * Validate that the context fields match between
-		 * registry and newcoming application.
-		 */
-		if (ust_reg_chan.get_context() != *context_fields) {
-			ERR("Registering application channel due to context field mismatch: pid = %d, sock = %d",
-				app->pid, app->sock);
-			ret_code = -EINVAL;
-			goto reply;
+			if (!previous_event_context) {
+				context_fields_match = app_context_fields.size() == 0;
+			} else {
+				const lst::structure_type app_event_context_struct(
+						0, std::move(app_context_fields));
+
+				context_fields_match = *previous_event_context ==
+						app_event_context_struct;
+			}
+
+			if (!context_fields_match) {
+				ERR("Registering application channel due to context field mismatch: pid = %d, sock = %d",
+						app->pid, app->sock);
+				ret_code = -EINVAL;
+				goto reply;
+			}
 		}
+	} catch (std::exception& ex) {
+		ERR("Failed to handle application context: %s", ex.what());
+		ret_code = -EINVAL;
+		goto reply;
 	}
 
 reply:
@@ -6539,12 +6565,16 @@ static int add_event_ust_registry(int sock, int sobjd, int cobjd, const char *na
 				channel.add_event(sobjd, cobjd, name, signature.get(),
 						lsu::create_trace_fields_from_ust_ctl_fields(
 								*locked_registry, fields.get(),
-								nr_fields),
+								nr_fields,
+								lst::field_location::root::
+										EVENT_RECORD_PAYLOAD,
+								lsu::ctl_field_quirks::
+										UNDERSCORE_PREFIXED_VARIANT_TAG_MAPPINGS),
 						loglevel_value,
 						model_emf_uri.get() ?
 								nonstd::optional<std::string>(
 										model_emf_uri.get()) :
-								      nonstd::nullopt,
+								nonstd::nullopt,
 						ua_sess->buffer_type, *app, event_id);
 				ret_code = 0;
 			} catch (const std::exception& ex) {
@@ -7865,3 +7895,30 @@ error:
 	rcu_read_unlock();
 	return ret;
 }
+
+lsu::ctl_field_quirks ust_app::ctl_field_quirks() const
+{
+	/*
+	 * Application contexts are expressed as variants. LTTng-UST announces
+	 * those by registering an enumeration named `..._tag`. It then registers a
+	 * variant as part of the event context that contains the various possible
+	 * types.
+	 *
+	 * Unfortunately, the names used in the enumeration and variant don't
+	 * match: the enumeration names are all prefixed with an underscore while
+	 * the variant type tag fields aren't.
+	 *
+	 * While the CTF 1.8.3 specification mentions that
+	 * underscores *should* (not *must*) be removed by CTF readers. Babeltrace
+	 * 1.x (and possibly others) expect a perfect match between the names used
+	 * by tags and variants.
+	 *
+	 * When the UNDERSCORE_PREFIXED_VARIANT_TAG_MAPPINGS quirk is enabled,
+	 * the variant's fields are modified to match the mappings of its tag.
+	 *
+	 * From ABI version >= 10.x, the variant fields and tag mapping names
+	 * correctly match, making this quirk unnecessary.
+	 */
+	return v_major <= 9 ? lsu::ctl_field_quirks::UNDERSCORE_PREFIXED_VARIANT_TAG_MAPPINGS :
+		lsu::ctl_field_quirks::NONE;
+}
\ No newline at end of file