From: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Date: Wed, 17 Mar 2021 05:10:27 +0000 (-0400)
Subject: on-event evaluation: introduce on-event evaluation specific status code
X-Git-Tag: v2.13.0-rc1~207
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=3ce811ee6c6c61a2c2c0909cf27e0dd8eea403fc;p=lttng-tools.git

on-event evaluation: introduce on-event evaluation specific status code

Before this change, `lttng_evaluation_on_event_get_captured_values`
returns `LTTNG_EVALUATION_STATUS_INVALID` when an evaluation's
condition has no capture descriptors. That status code is also used to
indicate a handful of "invalid parameter" conditions.

Not having captured values in an evaluation should not be considered an
error. Hence, a status enum that is specific to on-event evaluations is
added to introduce a "NONE" status that is not an error (positive value)
and wouldn't make sense for all evaluations (it could mean an error in
other circumstances).

`LTTNG_EVALUATION_ON_EVENT_STATUS_NONE` is returned when the condition
of an on-event evaluation has no capture descriptors.

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Change-Id: Ic2e3e90317a44c7bb3e95630956565690bffd760
---

diff --git a/include/lttng/condition/on-event.h b/include/lttng/condition/on-event.h
index 450507613..5114ec1fc 100644
--- a/include/lttng/condition/on-event.h
+++ b/include/lttng/condition/on-event.h
@@ -19,6 +19,12 @@ extern "C" {
 struct lttng_event_expr;
 struct lttng_event_field_value;
 
+enum lttng_evaluation_on_event_status {
+	LTTNG_EVALUATION_ON_EVENT_STATUS_NONE = 1,
+	LTTNG_EVALUATION_ON_EVENT_STATUS_OK = 0,
+	LTTNG_EVALUATION_ON_EVENT_STATUS_INVALID = -1,
+};
+
 /**
  * On event conditions allows an action to be taken whenever an event matching
  * the on event is hit by the tracers.
@@ -81,20 +87,22 @@ lttng_evaluation_on_event_get_trigger_name(
  *
  * Returns:
  *
- * `LTTNG_EVALUATION_STATUS_OK`:
+ * `LTTNG_EVALUATION_ON_EVENT_STATUS_OK`:
  *     Success.
  *
  *     `*field_val` is an array event field value with a length of at
  *     least one.
  *
- * `LTTNG_EVALUATION_STATUS_INVALID`:
+ * `LTTNG_EVALUATION_ON_EVENT_STATUS_INVALID`:
  *     * `evaluation` is `NULL`.
  *     * The type of the condition of `evaluation` is not
  *       `LTTNG_CONDITION_TYPE_ON_EVENT`.
- *     * The condition of `evaluation` has no capture descriptors.
  *     * `field_val` is `NULL`.
+ *
+ * `LTTNG_EVALUATION_ON_EVENT_STATUS_NONE`:
+ *     * The condition of `evaluation` has no capture descriptors.
  */
-extern enum lttng_evaluation_status
+extern enum lttng_evaluation_on_event_status
 lttng_evaluation_on_event_get_captured_values(
 		const struct lttng_evaluation *evaluation,
 		const struct lttng_event_field_value **field_val);
diff --git a/src/common/conditions/on-event.c b/src/common/conditions/on-event.c
index a10df868a..9cc80772c 100644
--- a/src/common/conditions/on-event.c
+++ b/src/common/conditions/on-event.c
@@ -1380,23 +1380,25 @@ error:
 	return evaluation;
 }
 
-enum lttng_evaluation_status lttng_evaluation_on_event_get_captured_values(
+enum lttng_evaluation_on_event_status
+lttng_evaluation_on_event_get_captured_values(
 		const struct lttng_evaluation *evaluation,
 		const struct lttng_event_field_value **field_val)
 {
 	struct lttng_evaluation_on_event *hit;
-	enum lttng_evaluation_status status = LTTNG_EVALUATION_STATUS_OK;
+	enum lttng_evaluation_on_event_status status =
+			LTTNG_EVALUATION_ON_EVENT_STATUS_OK;
 
 	if (!evaluation || !is_on_event_evaluation(evaluation) ||
 			!field_val) {
-		status = LTTNG_EVALUATION_STATUS_INVALID;
+		status = LTTNG_EVALUATION_ON_EVENT_STATUS_INVALID;
 		goto end;
 	}
 
 	hit = container_of(evaluation, struct lttng_evaluation_on_event,
 			parent);
 	if (!hit->captured_values) {
-		status = LTTNG_EVALUATION_STATUS_INVALID;
+		status = LTTNG_EVALUATION_ON_EVENT_STATUS_NONE;
 		goto end;
 	}
 
diff --git a/tests/regression/tools/notification/notification.c b/tests/regression/tools/notification/notification.c
index 68a76f922..e7101bb9f 100644
--- a/tests/regression/tools/notification/notification.c
+++ b/tests/regression/tools/notification/notification.c
@@ -2306,7 +2306,7 @@ static int validator_notification_trigger_capture(
 {
 	int ret;
 	unsigned int capture_count, i;
-	enum lttng_evaluation_status evaluation_status;
+	enum lttng_evaluation_on_event_status on_event_evaluation_status;
 	enum lttng_event_field_value_status event_field_value_status;
 	const struct lttng_evaluation *evaluation;
 	const struct lttng_event_field_value *captured_fields;
@@ -2319,11 +2319,12 @@ static int validator_notification_trigger_capture(
 		goto end;
 	}
 
-	evaluation_status = lttng_evaluation_on_event_get_captured_values(
-			evaluation, &captured_fields);
-	if (evaluation_status != LTTNG_EVALUATION_STATUS_OK) {
+	on_event_evaluation_status =
+			lttng_evaluation_on_event_get_captured_values(
+					evaluation, &captured_fields);
+	if (on_event_evaluation_status != LTTNG_EVALUATION_ON_EVENT_STATUS_OK) {
 		diag("Failed to get event rule evaluation captured values: status = %d",
-				(int) evaluation_status);
+				(int) on_event_evaluation_status);
 		ret = 1;
 		goto end;
 	}