From 5ba3702f9f88e499d9b440a9cd88b5efa3931ab2 Mon Sep 17 00:00:00 2001
From: =?utf8?q?J=C3=A9r=C3=A9mie=20Galarneau?=
 <jeremie.galarneau@efficios.com>
Date: Mon, 7 Mar 2016 17:38:04 -0500
Subject: [PATCH] Add channel discarded events and lost packets stats accessors
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Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
---
 include/lttng/channel.h                  | 17 ++++++++
 src/common/sessiond-comm/sessiond-comm.h |  8 ++++
 src/lib/lttng-ctl/lttng-ctl.c            | 52 ++++++++++++++++++++++++
 3 files changed, 77 insertions(+)

diff --git a/include/lttng/channel.h b/include/lttng/channel.h
index e770f6835..622ce85e9 100644
--- a/include/lttng/channel.h
+++ b/include/lttng/channel.h
@@ -20,6 +20,7 @@
 
 #include <lttng/domain.h>
 #include <lttng/event.h>
+#include <stdint.h>
 
 #ifdef __cplusplus
 extern "C" {
@@ -107,6 +108,22 @@ extern int lttng_disable_channel(struct lttng_handle *handle,
 extern void lttng_channel_set_default_attr(struct lttng_domain *domain,
 		struct lttng_channel_attr *attr);
 
+/*
+ * Get the discarded event count of a specific LTTng channel.
+ *
+ * Returns 0 on success, or a negative LTTng error code on error.
+ */
+extern int lttng_channel_get_discarded_event_count(struct lttng_channel *chan,
+		uint64_t *discarded_events);
+
+/*
+ * Get the lost packet count of a specific LTTng channel.
+ *
+ * Returns 0 on success, or a negative LTTng error code on error.
+ */
+extern int lttng_channel_get_lost_packet_count(struct lttng_channel *chan,
+		uint64_t *lost_packets);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/src/common/sessiond-comm/sessiond-comm.h b/src/common/sessiond-comm/sessiond-comm.h
index 575fbf019..d436094ff 100644
--- a/src/common/sessiond-comm/sessiond-comm.h
+++ b/src/common/sessiond-comm/sessiond-comm.h
@@ -369,6 +369,14 @@ struct lttcomm_event_extended_header {
 	uint32_t nb_exclusions;
 } LTTNG_PACKED;
 
+/*
+ * Channel extended info.
+ */
+struct lttcomm_channel_extended {
+	uint64_t discarded_events;
+	uint64_t lost_packets;
+} LTTNG_PACKED;
+
 /*
  * Data structure for the response from sessiond to the lttng client.
  */
diff --git a/src/lib/lttng-ctl/lttng-ctl.c b/src/lib/lttng-ctl/lttng-ctl.c
index c7665922f..6c10c910d 100644
--- a/src/lib/lttng-ctl/lttng-ctl.c
+++ b/src/lib/lttng-ctl/lttng-ctl.c
@@ -1974,6 +1974,58 @@ void lttng_channel_set_default_attr(struct lttng_domain *domain,
 	}
 }
 
+int lttng_channel_get_discarded_event_count(struct lttng_channel *channel,
+		uint64_t *discarded_events)
+{
+	int ret = 0;
+	struct lttcomm_channel_extended *chan_ext;
+
+	if (!channel || !discarded_events) {
+		ret = -LTTNG_ERR_INVALID;
+		goto end;
+	}
+
+	chan_ext = channel->attr.extended.ptr;
+	if (!chan_ext) {
+		/*
+		 * This can happen since the lttng_channel structure is
+		 * used for other tasks where this pointer is never set.
+		 */
+		*discarded_events = 0;
+		goto end;
+	}
+
+	*discarded_events = chan_ext->discarded_events;
+end:
+	return ret;
+}
+
+int lttng_channel_get_lost_packet_count(struct lttng_channel *channel,
+		uint64_t *lost_packets)
+{
+	int ret = 0;
+	struct lttcomm_channel_extended *chan_ext;
+
+	if (!channel || !lost_packets) {
+		ret = -LTTNG_ERR_INVALID;
+		goto end;
+	}
+
+	chan_ext = channel->attr.extended.ptr;
+	if (!chan_ext) {
+		/*
+		 * This can happen since the lttng_channel structure is
+		 * used for other tasks where this pointer is never set.
+		 */
+		*lost_packets = 0;
+		goto end;
+	}
+
+	*lost_packets = chan_ext->lost_packets;
+end:
+	return ret;
+}
+
 /*
  * Check if session daemon is alive.
  *
-- 
2.34.1