+
+static
+int consumer_flush_buffer(struct lttng_consumer_stream *stream, int producer_active)
+{
+ int ret = 0;
+
+ switch (consumer_data.type) {
+ case LTTNG_CONSUMER_KERNEL:
+ ret = kernctl_buffer_flush(stream->wait_fd);
+ if (ret < 0) {
+ ERR("Failed to flush kernel stream");
+ goto end;
+ }
+ break;
+ case LTTNG_CONSUMER32_UST:
+ case LTTNG_CONSUMER64_UST:
+ lttng_ustconsumer_flush_buffer(stream, producer_active);
+ break;
+ default:
+ ERR("Unknown consumer_data type");
+ abort();
+ }
+
+end:
+ return ret;
+}
+
+static
+int consumer_clear_buffer(struct lttng_consumer_stream *stream)
+{
+ int ret = 0;
+
+ switch (consumer_data.type) {
+ case LTTNG_CONSUMER_KERNEL:
+ ret = kernctl_buffer_clear(stream->wait_fd);
+ if (ret < 0) {
+ ERR("Failed to flush kernel stream");
+ goto end;
+ }
+ break;
+ case LTTNG_CONSUMER32_UST:
+ case LTTNG_CONSUMER64_UST:
+ lttng_ustconsumer_clear_buffer(stream);
+ break;
+ default:
+ ERR("Unknown consumer_data type");
+ abort();
+ }
+
+end:
+ return ret;
+}
+
+static
+int consumer_unlink_stream_files_rotation(struct lttng_consumer_stream *stream)
+{
+ uint64_t tracefile_size = stream->chan->tracefile_size;
+ uint64_t tracefile_count = stream->chan->tracefile_count;
+ uint64_t count;
+ int ret;
+
+ /*
+ * If the channel is configured to have an open-ended number of tracefiles,
+ * use the current tracefile count number as upper-bound.
+ */
+ if (!tracefile_count) {
+ tracefile_count = stream->tracefile_count_current + 1;
+ }
+
+ /*
+ * Try to unlink each file and each index for this stream. They may not exist,
+ * in which case ENOENT is fine.
+ */
+ for (count = 0; count < tracefile_count; count++) {
+ ret = utils_unlink_stream_file(stream->chan->pathname, stream->name,
+ tracefile_size, count, stream->uid, stream->gid, NULL);
+ if (ret < 0 && errno != ENOENT) {
+ return LTTCOMM_CONSUMERD_FATAL;
+ }
+ if (stream->index_file) {
+ ret = lttng_index_file_unlink(stream->chan->pathname, stream->name,
+ stream->uid, stream->gid, tracefile_size, count);
+ if (ret < 0 && errno != ENOENT) {
+ return LTTCOMM_CONSUMERD_FATAL;
+ }
+ }
+ }
+ return LTTCOMM_CONSUMERD_SUCCESS;
+}
+
+static
+int consumer_unlink_stream_files(struct lttng_consumer_stream *stream)
+{
+ uint64_t tracefile_size = stream->chan->tracefile_size;
+ int ret;
+
+ /* No tracefile rotation, a single file to unlink and re-create. */
+ ret = utils_unlink_stream_file(stream->chan->pathname, stream->name,
+ tracefile_size, 0, stream->uid, stream->gid, 0);
+ if (ret < 0 && errno != ENOENT) {
+ return LTTCOMM_CONSUMERD_FATAL;
+ }
+ return LTTCOMM_CONSUMERD_SUCCESS;
+}
+
+static
+int consumer_clear_stream_files(struct lttng_consumer_stream *stream)
+{
+ int ret;
+ uint64_t tracefile_size = stream->chan->tracefile_size;
+
+ /*
+ * If stream is sent over to a relay daemon, there are no local files
+ * to unlink.
+ */
+ if (stream->net_seq_idx != (uint64_t) -1ULL) {
+ return LTTCOMM_CONSUMERD_SUCCESS;
+ }
+
+ ret = close(stream->out_fd);
+ if (ret < 0) {
+ PERROR("Closing tracefile");
+ return LTTCOMM_CONSUMERD_FATAL;
+ }
+ stream->out_fd = -1;
+ stream->out_fd_offset = 0;
+ stream->tracefile_size_current = 0;
+
+ /*
+ * Re-creation of the index file takes care of clearing its
+ * content for non-tracefile-rotation streams.
+ * Rotation streams need to explicitly unlink each index file.
+ * We put the stream file, but keep the stream->index_file value
+ * as indication whether the stream has index (non-NULL) before
+ * overwriting it with an index creation.
+ */
+ if (stream->index_file) {
+ lttng_index_file_put(stream->index_file);
+ }
+
+ if (tracefile_size > 0) {
+ /* Tracefile rotation. */
+ ret = consumer_unlink_stream_files_rotation(stream);
+ } else {
+ ret = consumer_unlink_stream_files(stream);
+ }
+ if (ret != LTTCOMM_CONSUMERD_SUCCESS) {
+ return ret;
+ }
+
+ /* Create new files. */
+ ret = utils_create_stream_file(stream->chan->pathname, stream->name,
+ tracefile_size, 0, stream->uid, stream->gid, 0);
+ if (ret < 0) {
+ return LTTCOMM_CONSUMERD_FATAL;
+ }
+ stream->out_fd = ret;
+
+ if (stream->index_file) {
+ stream->index_file = lttng_index_file_create(stream->chan->pathname,
+ stream->name, stream->uid, stream->gid, tracefile_size,
+ 0, CTF_INDEX_MAJOR, CTF_INDEX_MINOR);
+ if (!stream->index_file) {
+ return LTTCOMM_CONSUMERD_FATAL;
+ }
+ }
+
+ return LTTCOMM_CONSUMERD_SUCCESS;
+}
+
+static
+int consumer_clear_stream(struct lttng_consumer_stream *stream)
+{
+ int ret;
+
+ ret = consumer_flush_buffer(stream, 1);
+ if (ret < 0) {
+ ERR("Failed to flush stream %" PRIu64 " during channel clear",
+ stream->key);
+ ret = LTTCOMM_CONSUMERD_FATAL;
+ goto error;
+ }
+
+ ret = consumer_clear_buffer(stream);
+ if (ret < 0) {
+ ERR("Failed to clear stream %" PRIu64 " during channel clear",
+ stream->key);
+ ret = LTTCOMM_CONSUMERD_FATAL;
+ goto error;
+ }
+
+ ret = consumer_clear_stream_files(stream);
+ if (ret != LTTCOMM_CONSUMERD_SUCCESS) {
+ ERR("Failed to clear stream %" PRIu64 " files during channel clear",
+ stream->key);
+ goto error;
+ }
+ ret = LTTCOMM_CONSUMERD_SUCCESS;
+error:
+ return ret;
+}
+
+static
+int consumer_clear_unmonitored_channel(struct lttng_consumer_channel *channel)
+{
+ int ret;
+ struct lttng_consumer_stream *stream;
+
+ rcu_read_lock();
+ pthread_mutex_lock(&channel->lock);
+ cds_list_for_each_entry(stream, &channel->streams.head, send_node) {
+ health_code_update();
+ pthread_mutex_lock(&stream->lock);
+ ret = consumer_clear_stream(stream);
+ if (ret) {
+ goto error_unlock;
+ }
+ pthread_mutex_unlock(&stream->lock);
+ }
+ pthread_mutex_unlock(&channel->lock);
+ rcu_read_unlock();
+ return 0;
+
+error_unlock:
+ pthread_mutex_unlock(&stream->lock);
+ pthread_mutex_unlock(&channel->lock);
+ rcu_read_unlock();
+ if (ret)
+ goto error;
+ ret = LTTCOMM_CONSUMERD_SUCCESS;
+error:
+ return ret;
+
+}
+
+static
+int consumer_clear_monitored_channel(struct lttng_consumer_channel *channel)
+{
+ struct lttng_ht *ht;
+ struct lttng_consumer_stream *stream;
+ struct lttng_ht_iter iter;
+ int ret;
+
+ ht = consumer_data.stream_per_chan_id_ht;
+
+ rcu_read_lock();
+ cds_lfht_for_each_entry_duplicate(ht->ht,
+ ht->hash_fct(&channel->key, lttng_ht_seed),
+ ht->match_fct, &channel->key,
+ &iter.iter, stream, node_channel_id.node) {
+ /*
+ * Protect against teardown with mutex.
+ */
+ pthread_mutex_lock(&stream->lock);
+ if (cds_lfht_is_node_deleted(&stream->node.node)) {
+ goto next;
+ }
+ ret = consumer_clear_stream(stream);
+ if (ret) {
+ goto error_unlock;
+ }
+ next:
+ pthread_mutex_unlock(&stream->lock);
+ }
+ rcu_read_unlock();
+ return LTTCOMM_CONSUMERD_SUCCESS;
+
+error_unlock:
+ pthread_mutex_unlock(&stream->lock);
+ rcu_read_unlock();
+ return ret;
+}
+
+int lttng_consumer_clear_channel(struct lttng_consumer_channel *channel)
+{
+ int ret;
+
+ DBG("Consumer clear channel %" PRIu64, channel->key);
+
+ if (channel->type == CONSUMER_CHANNEL_TYPE_METADATA) {
+ /*
+ * Nothing to do for the metadata channel/stream.
+ * Snapshot mechanism already take care of the metadata
+ * handling/generation, and monitored channels only need to
+ * have their data stream cleared..
+ */
+ ret = LTTCOMM_CONSUMERD_SUCCESS;
+ goto end;
+ }
+
+ if (!channel->monitor) {
+ ret = consumer_clear_unmonitored_channel(channel);
+ } else {
+ ret = consumer_clear_monitored_channel(channel);
+ }
+end:
+ return ret;
+}
+
+int lttng_consumer_clear_session(uint64_t session_id)
+{
+ struct lttng_ht_iter iter;
+ struct lttng_consumer_stream *stream;
+ int ret;
+
+ DBG("Consumer clear session %" PRIu64, session_id);
+
+ rcu_read_lock();
+
+ /* Find first stream match in data_ht. */
+ cds_lfht_for_each_entry(data_ht->ht, &iter.iter, stream, node.node) {
+ if (stream->chan->session_id == session_id) {
+ struct consumer_relayd_sock_pair *relayd = NULL;
+
+ if (stream->net_seq_idx == (uint64_t) -1ULL) {
+ /*
+ * Asking for a clear session on local session.
+ * No relayd to contact, nothing to do.
+ */
+ break; /* Stop after first match. */
+ }
+ relayd = consumer_find_relayd(stream->net_seq_idx);
+ if (relayd == NULL) {
+ /*
+ * relayd is shutting down.
+ */
+ ret = LTTCOMM_CONSUMERD_SUCCESS;
+ goto end;
+ }
+ ret = relayd_clear_session(&relayd->control_sock);
+ if (ret < 0) {
+ ret = LTTCOMM_CONSUMERD_FATAL;
+ goto end;
+ }
+ break; /* Stop after first match. */
+
+ }
+ }
+ ret = LTTCOMM_CONSUMERD_SUCCESS;
+end:
+ rcu_read_unlock();
+ return ret;
+}