[lttng-dev] [UST PATCH 2/2] LTTng ringbuffer ABI calls for index generation

[Julien Desfossez]

These new calls export the data required for the consumer to
generate the index while tracing :
- timestamp begin
- timestamp end
- events discarded
- context size
- packet size
- stream id

Signed-off-by: Julien Desfossez <jdesfossez at efficios.com>
---
 include/lttng/ust-ctl.h                 |   14 ++++
 liblttng-ust-ctl/ustctl.c               |  125 +++++++++++++++++++++++++++++++
 liblttng-ust/lttng-rb-clients.h         |   19 +++++
 liblttng-ust/lttng-ring-buffer-client.h |   91 ++++++++++++++++++++++
 4 files changed, 249 insertions(+)

diff --git a/include/lttng/ust-ctl.h b/include/lttng/ust-ctl.h
index 3c81e50..88112ad 100644
--- a/include/lttng/ust-ctl.h
+++ b/include/lttng/ust-ctl.h
@@ -220,6 +220,20 @@ int ustctl_put_subbuf(struct ustctl_consumer_stream *stream);
 void ustctl_flush_buffer(struct ustctl_consumer_stream *stream,
 		int producer_active);
 
+/* index */
+int ustctl_get_timestamp_begin(struct ustctl_consumer_stream *stream,
+		uint64_t *timestamp_begin);
+int ustctl_get_timestamp_end(struct ustctl_consumer_stream *stream,
+	uint64_t *timestamp_end);
+int ustctl_get_events_discarded(struct ustctl_consumer_stream *stream,
+	uint64_t *events_discarded);
+int ustctl_get_content_size(struct ustctl_consumer_stream *stream,
+	uint64_t *content_size);
+int ustctl_get_packet_size(struct ustctl_consumer_stream *stream,
+	uint64_t *packet_size);
+int ustctl_get_stream_id(struct ustctl_consumer_stream *stream,
+		uint64_t *stream_id);
+
 /* event registry management */
 
 enum ustctl_socket_type {
diff --git a/liblttng-ust-ctl/ustctl.c b/liblttng-ust-ctl/ustctl.c
index 28dee5e..9255416 100644
--- a/liblttng-ust-ctl/ustctl.c
+++ b/liblttng-ust-ctl/ustctl.c
@@ -31,6 +31,7 @@
 #include "../libringbuffer/backend.h"
 #include "../libringbuffer/frontend.h"
 #include "../liblttng-ust/wait.h"
+#include "../liblttng-ust/lttng-rb-clients.h"
 
 /*
  * Number of milliseconds to retry before failing metadata writes on
@@ -1461,6 +1462,130 @@ void ustctl_flush_buffer(struct ustctl_consumer_stream *stream,
 		consumer_chan->chan->handle);
 }
 
+static
+struct lttng_ust_client_lib_ring_buffer_client_cb *get_client_cb(
+		struct lttng_ust_lib_ring_buffer *buf,
+		struct lttng_ust_shm_handle *handle)
+{
+	struct channel *chan;
+	const struct lttng_ust_lib_ring_buffer_config *config;
+	struct lttng_ust_client_lib_ring_buffer_client_cb *client_cb;
+
+	chan = shmp(handle, buf->backend.chan);
+	config = &chan->backend.config;
+
+	if (!config->cb_ptr)
+		return NULL;
+
+	client_cb = caa_container_of(config->cb_ptr,
+			struct lttng_ust_client_lib_ring_buffer_client_cb,
+			parent);
+
+	return client_cb;
+}
+
+int ustctl_get_timestamp_begin(struct ustctl_consumer_stream *stream,
+		uint64_t *timestamp_begin)
+{
+	struct lttng_ust_client_lib_ring_buffer_client_cb *client_cb;
+	struct lttng_ust_lib_ring_buffer *buf = stream->buf;
+	struct lttng_ust_shm_handle *handle = stream->chan->chan->handle;
+
+	if (!stream || !timestamp_begin)
+		return -EINVAL;
+
+	client_cb = get_client_cb(buf, handle);
+	if (!client_cb)
+		return -ENOSYS;
+
+	return client_cb->timestamp_begin(buf, handle, timestamp_begin);
+}
+
+int ustctl_get_timestamp_end(struct ustctl_consumer_stream *stream,
+	uint64_t *timestamp_end)
+{
+	struct lttng_ust_client_lib_ring_buffer_client_cb *client_cb;
+	struct lttng_ust_lib_ring_buffer *buf = stream->buf;
+	struct lttng_ust_shm_handle *handle = stream->chan->chan->handle;
+
+	if (!stream || !timestamp_end)
+		return -EINVAL;
+
+	client_cb = get_client_cb(buf, handle);
+	if (!client_cb)
+		return -ENOSYS;
+
+	return client_cb->timestamp_end(buf, handle, timestamp_end);
+}
+
+int ustctl_get_events_discarded(struct ustctl_consumer_stream *stream,
+	uint64_t *events_discarded)
+{
+	struct lttng_ust_client_lib_ring_buffer_client_cb *client_cb;
+	struct lttng_ust_lib_ring_buffer *buf = stream->buf;
+	struct lttng_ust_shm_handle *handle = stream->chan->chan->handle;
+
+	if (!stream || !events_discarded)
+		return -EINVAL;
+
+	client_cb = get_client_cb(buf, handle);
+	if (!client_cb)
+		return -ENOSYS;
+
+	return client_cb->events_discarded(buf, handle, events_discarded);
+}
+
+int ustctl_get_content_size(struct ustctl_consumer_stream *stream,
+	uint64_t *content_size)
+{
+	struct lttng_ust_client_lib_ring_buffer_client_cb *client_cb;
+	struct lttng_ust_lib_ring_buffer *buf = stream->buf;
+	struct lttng_ust_shm_handle *handle = stream->chan->chan->handle;
+
+	if (!stream || !content_size)
+		return -EINVAL;
+
+	client_cb = get_client_cb(buf, handle);
+	if (!client_cb)
+		return -ENOSYS;
+
+	return client_cb->content_size(buf, handle, content_size);
+}
+
+int ustctl_get_packet_size(struct ustctl_consumer_stream *stream,
+	uint64_t *packet_size)
+{
+	struct lttng_ust_client_lib_ring_buffer_client_cb *client_cb;
+	struct lttng_ust_lib_ring_buffer *buf = stream->buf;
+	struct lttng_ust_shm_handle *handle = stream->chan->chan->handle;
+
+	if (!stream || !packet_size)
+		return -EINVAL;
+
+	client_cb = get_client_cb(buf, handle);
+	if (!client_cb)
+		return -ENOSYS;
+
+	return client_cb->packet_size(buf, handle, packet_size);
+}
+
+int ustctl_get_stream_id(struct ustctl_consumer_stream *stream,
+		uint64_t *stream_id)
+{
+	struct lttng_ust_client_lib_ring_buffer_client_cb *client_cb;
+	struct lttng_ust_lib_ring_buffer *buf = stream->buf;
+	struct lttng_ust_shm_handle *handle = stream->chan->chan->handle;
+
+	if (!stream || !stream_id)
+		return -EINVAL;
+
+	client_cb = get_client_cb(buf, handle);
+	if (!client_cb)
+		return -ENOSYS;
+
+	return client_cb->stream_id(buf, handle, stream_id);
+}
+
 /*
  * Returns 0 on success, negative error value on error.
  */
diff --git a/liblttng-ust/lttng-rb-clients.h b/liblttng-ust/lttng-rb-clients.h
index c9a1619..c43aa75 100644
--- a/liblttng-ust/lttng-rb-clients.h
+++ b/liblttng-ust/lttng-rb-clients.h
@@ -21,6 +21,25 @@
 
 struct lttng_ust_client_lib_ring_buffer_client_cb {
 	struct lttng_ust_lib_ring_buffer_client_cb parent;
+
+	int (*timestamp_begin) (struct lttng_ust_lib_ring_buffer *buf,
+			struct lttng_ust_shm_handle *handle,
+			uint64_t *timestamp_begin);
+	int (*timestamp_end) (struct lttng_ust_lib_ring_buffer *buf,
+			struct lttng_ust_shm_handle *handle,
+			uint64_t *timestamp_end);
+	int (*events_discarded) (struct lttng_ust_lib_ring_buffer *buf,
+			struct lttng_ust_shm_handle *handle,
+			uint64_t *events_discarded);
+	int (*content_size) (struct lttng_ust_lib_ring_buffer *buf,
+			struct lttng_ust_shm_handle *handle,
+			uint64_t *content_size);
+	int (*packet_size) (struct lttng_ust_lib_ring_buffer *buf,
+			struct lttng_ust_shm_handle *handle,
+			uint64_t *packet_size);
+	int (*stream_id) (struct lttng_ust_lib_ring_buffer *buf,
+			struct lttng_ust_shm_handle *handle,
+			uint64_t *stream_id);
 };
 
 #endif /* _LTTNG_RB_CLIENT_H */
diff --git a/liblttng-ust/lttng-ring-buffer-client.h b/liblttng-ust/lttng-ring-buffer-client.h
index 383fce0..5ce672c 100644
--- a/liblttng-ust/lttng-ring-buffer-client.h
+++ b/liblttng-ust/lttng-ring-buffer-client.h
@@ -386,6 +386,91 @@ static void client_buffer_finalize(struct lttng_ust_lib_ring_buffer *buf, void *
 {
 }
 
+static struct packet_header *client_packet_header(struct lttng_ust_lib_ring_buffer *buf,
+		struct lttng_ust_shm_handle *handle)
+{
+	struct channel *chan = shmp(handle, buf->backend.chan);
+	struct lttng_channel *lttng_chan = channel_get_private(chan);
+	unsigned long sb_index;
+	struct lttng_ust_lib_ring_buffer_backend *bufb;
+	struct packet_header *header;
+
+	bufb = &buf->backend;
+	sb_index = subbuffer_id_get_index(&lttng_chan->chan->backend.config,
+			bufb->buf_rsb.id);
+
+	header = lib_ring_buffer_offset_address(bufb,
+			sb_index * lttng_chan->chan->backend.subbuf_size,
+			handle);
+
+	return header;
+}
+
+static int client_timestamp_begin(struct lttng_ust_lib_ring_buffer *buf,
+		struct lttng_ust_shm_handle *handle,
+		uint64_t *timestamp_begin)
+{
+	struct packet_header *header = client_packet_header(buf, handle);
+
+	*timestamp_begin = header->ctx.timestamp_begin;
+
+	return 0;
+}
+
+static int client_timestamp_end(struct lttng_ust_lib_ring_buffer *buf,
+		struct lttng_ust_shm_handle *handle,
+		uint64_t *timestamp_end)
+{
+	struct packet_header *header = client_packet_header(buf, handle);
+
+	*timestamp_end = header->ctx.timestamp_end;
+
+	return 0;
+}
+
+static int client_events_discarded(struct lttng_ust_lib_ring_buffer *buf,
+		struct lttng_ust_shm_handle *handle,
+		uint64_t *events_discarded)
+{
+	struct packet_header *header = client_packet_header(buf, handle);
+
+	*events_discarded = header->ctx.events_discarded;
+
+	return 0;
+}
+
+static int client_content_size(struct lttng_ust_lib_ring_buffer *buf,
+		struct lttng_ust_shm_handle *handle,
+		uint64_t *content_size)
+{
+	struct packet_header *header = client_packet_header(buf, handle);
+
+	*content_size = header->ctx.content_size;
+
+	return 0;
+}
+
+static int client_packet_size(struct lttng_ust_lib_ring_buffer *buf,
+		struct lttng_ust_shm_handle *handle,
+		uint64_t *packet_size)
+{
+	struct packet_header *header = client_packet_header(buf, handle);
+
+	*packet_size = header->ctx.packet_size;
+
+	return 0;
+}
+
+static int client_stream_id(struct lttng_ust_lib_ring_buffer *buf,
+		struct lttng_ust_shm_handle *handle,
+		uint64_t *stream_id)
+{
+	struct packet_header *header = client_packet_header(buf, handle);
+
+	*stream_id = header->stream_id;
+
+	return 0;
+}
 static const
 struct lttng_ust_client_lib_ring_buffer_client_cb client_cb = {
 	.parent = {
@@ -397,6 +482,12 @@ struct lttng_ust_client_lib_ring_buffer_client_cb client_cb = {
 		.buffer_create = client_buffer_create,
 		.buffer_finalize = client_buffer_finalize,
 	},
+	.timestamp_begin = client_timestamp_begin,
+	.timestamp_end = client_timestamp_end,
+	.events_discarded = client_events_discarded,
+	.content_size = client_content_size,
+	.packet_size = client_packet_size,
+	.stream_id = client_stream_id,
 };
 
 static const struct lttng_ust_lib_ring_buffer_config client_config = {
-- 
1.7.10.4