[lttng-dev] [MODULES PATCH 3/4] Per-stream ioctl to get the current timestamp

[Julien Desfossez]

Signed-off-by: Julien Desfossez <jdesfossez at efficios.com>
---
 lttng-abi.c                         | 22 ++++++++++++++++++++++
 lttng-abi.h                         |  5 +++++
 lttng-events.h                      |  3 +++
 lttng-ring-buffer-client.h          | 10 ++++++++++
 lttng-ring-buffer-metadata-client.h |  8 ++++++++
 5 files changed, 48 insertions(+)

diff --git a/lttng-abi.c b/lttng-abi.c
index c2560e0..224b352 100644
--- a/lttng-abi.c
+++ b/lttng-abi.c
@@ -1408,6 +1408,17 @@ static long lttng_stream_ring_buffer_ioctl(struct file *filp,
 			goto error;
 		return put_u64(si, arg);
 	}
+	case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
+	{
+		uint64_t ts;
+
+		if (!lttng_chan->ops)
+			goto error;
+		ret = lttng_chan->ops->current_timestamp(config, buf, &ts);
+		if (ret < 0)
+			goto error;
+		return put_u64(ts, arg);
+	}
 	default:
 		return lib_ring_buffer_file_operations.unlocked_ioctl(filp,
 				cmd, arg);
@@ -1497,6 +1508,17 @@ static long lttng_stream_ring_buffer_compat_ioctl(struct file *filp,
 			goto error;
 		return put_u64(si, arg);
 	}
+	case LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP:
+	{
+		uint64_t ts;
+
+		if (!lttng_chan->ops)
+			goto error;
+		ret = lttng_chan->ops->current_timestamp(config, buf, &ts);
+		if (ret < 0)
+			goto error;
+		return put_u64(ts, arg);
+	}
 	default:
 		return lib_ring_buffer_file_operations.compat_ioctl(filp,
 				cmd, arg);
diff --git a/lttng-abi.h b/lttng-abi.h
index b028f1e..3f2aefb 100644
--- a/lttng-abi.h
+++ b/lttng-abi.h
@@ -187,6 +187,8 @@ struct lttng_kernel_context {
 #define LTTNG_RING_BUFFER_GET_PACKET_SIZE	_IOR(0xF6, 0x24, uint64_t)
 /* returns the stream id */
 #define LTTNG_RING_BUFFER_GET_STREAM_ID		_IOR(0xF6, 0x25, uint64_t)
+/* returns the current timestamp */
+#define LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP	_IOR(0xF6, 0x26, uint64_t)
 
 #ifdef CONFIG_COMPAT
 /* returns the timestamp begin of the current sub-buffer */
@@ -207,6 +209,9 @@ struct lttng_kernel_context {
 /* returns the stream id */
 #define LTTNG_RING_BUFFER_COMPAT_GET_STREAM_ID \
 	LTTNG_RING_BUFFER_GET_STREAM_ID
+/* returns the current timestamp */
+#define LTTNG_RING_BUFFER_COMPAT_GET_CURRENT_TIMESTAMP \
+	LTTNG_RING_BUFFER_GET_CURRENT_TIMESTAMP
 #endif /* CONFIG_COMPAT */
 
 #endif /* _LTTNG_ABI_H */
diff --git a/lttng-events.h b/lttng-events.h
index bce6507..f0628c4 100644
--- a/lttng-events.h
+++ b/lttng-events.h
@@ -263,6 +263,9 @@ struct lttng_channel_ops {
 	int (*stream_id) (const struct lib_ring_buffer_config *config,
 			struct lib_ring_buffer *bufb,
 			uint64_t *stream_id);
+	int (*current_timestamp) (const struct lib_ring_buffer_config *config,
+			struct lib_ring_buffer *bufb,
+			uint64_t *ts);
 };
 
 struct lttng_transport {
diff --git a/lttng-ring-buffer-client.h b/lttng-ring-buffer-client.h
index 167000a..50c47b3 100644
--- a/lttng-ring-buffer-client.h
+++ b/lttng-ring-buffer-client.h
@@ -467,6 +467,15 @@ static int client_stream_id(const struct lib_ring_buffer_config *config,
 	return 0;
 }
 
+static int client_current_timestamp(const struct lib_ring_buffer_config *config,
+		struct lib_ring_buffer *bufb,
+		uint64_t *ts)
+{
+	*ts = config->cb.ring_buffer_clock_read(bufb->backend.chan);
+
+	return 0;
+}
+
 static const struct lib_ring_buffer_config client_config = {
 	.cb.ring_buffer_clock_read = client_ring_buffer_clock_read,
 	.cb.record_header_size = client_record_header_size,
@@ -500,6 +509,7 @@ struct channel *_channel_create(const char *name,
 	lttng_chan->ops->content_size = client_content_size;
 	lttng_chan->ops->packet_size = client_packet_size;
 	lttng_chan->ops->stream_id = client_stream_id;
+	lttng_chan->ops->current_timestamp = client_current_timestamp;
 
 	return channel_create(&client_config, name, lttng_chan, buf_addr,
 			      subbuf_size, num_subbuf, switch_timer_interval,
diff --git a/lttng-ring-buffer-metadata-client.h b/lttng-ring-buffer-metadata-client.h
index 6130715..bea482b 100644
--- a/lttng-ring-buffer-metadata-client.h
+++ b/lttng-ring-buffer-metadata-client.h
@@ -168,6 +168,13 @@ static int client_events_discarded(const struct lib_ring_buffer_config *config,
 	return -ENOSYS;
 }
 
+static int client_current_timestamp(const struct lib_ring_buffer_config *config,
+		struct lib_ring_buffer *bufb,
+		uint64_t *ts)
+{
+	return -ENOSYS;
+}
+
 static int client_content_size(const struct lib_ring_buffer_config *config,
 			struct lib_ring_buffer *bufb,
 			uint64_t *content_size)
@@ -222,6 +229,7 @@ struct channel *_channel_create(const char *name,
 	lttng_chan->ops->content_size = client_content_size;
 	lttng_chan->ops->packet_size = client_packet_size;
 	lttng_chan->ops->stream_id = client_stream_id;
+	lttng_chan->ops->current_timestamp = client_current_timestamp;
 
 	return channel_create(&client_config, name, lttng_chan, buf_addr,
 			      subbuf_size, num_subbuf, switch_timer_interval,
-- 
1.8.3.2