Cleanup: namespace 'align' macros
[lttng-tools.git] / src / common / consumer / consumer.c
index 8d9fa06478cddc7a83904e76664aa21550cf527c..84fdbcaaa6902e076476489c3ab4e6b1aa7a1c9a 100644 (file)
@@ -9,7 +9,6 @@
 
 #include "common/index/ctf-index.h"
 #define _LGPL_SOURCE
-#include <assert.h>
 #include <poll.h>
 #include <pthread.h>
 #include <stdlib.h>
 #include <common/string-utils/format.h>
 #include <common/dynamic-array.h>
 
-struct lttng_consumer_global_data consumer_data = {
-       .stream_count = 0,
-       .need_update = 1,
-       .type = LTTNG_CONSUMER_UNKNOWN,
+struct lttng_consumer_global_data the_consumer_data = {
+               .stream_count = 0,
+               .need_update = 1,
+               .type = LTTNG_CONSUMER_UNKNOWN,
 };
 
 enum consumer_channel_action {
@@ -84,7 +83,7 @@ static struct lttng_ht *data_ht;
 
 static const char *get_consumer_domain(void)
 {
-       switch (consumer_data.type) {
+       switch (the_consumer_data.type) {
        case LTTNG_CONSUMER_KERNEL:
                return DEFAULT_KERNEL_TRACE_DIR;
        case LTTNG_CONSUMER64_UST:
@@ -105,7 +104,7 @@ static void notify_thread_lttng_pipe(struct lttng_pipe *pipe)
 {
        struct lttng_consumer_stream *null_stream = NULL;
 
-       assert(pipe);
+       LTTNG_ASSERT(pipe);
 
        (void) lttng_pipe_write(pipe, &null_stream, sizeof(null_stream));
 }
@@ -173,7 +172,7 @@ static void clean_channel_stream_list(struct lttng_consumer_channel *channel)
 {
        struct lttng_consumer_stream *stream, *stmp;
 
-       assert(channel);
+       LTTNG_ASSERT(channel);
 
        /* Delete streams that might have been left in the stream list. */
        cds_list_for_each_entry_safe(stream, stmp, &channel->streams.head,
@@ -201,7 +200,7 @@ static struct lttng_consumer_stream *find_stream(uint64_t key,
        struct lttng_ht_node_u64 *node;
        struct lttng_consumer_stream *stream = NULL;
 
-       assert(ht);
+       LTTNG_ASSERT(ht);
 
        /* -1ULL keys are lookup failures */
        if (key == (uint64_t) -1ULL) {
@@ -256,7 +255,7 @@ struct lttng_consumer_channel *consumer_find_channel(uint64_t key)
                return NULL;
        }
 
-       lttng_ht_lookup(consumer_data.channel_ht, &key, &iter);
+       lttng_ht_lookup(the_consumer_data.channel_ht, &key, &iter);
        node = lttng_ht_iter_get_node_u64(&iter);
        if (node != NULL) {
                channel = caa_container_of(node, struct lttng_consumer_channel, node);
@@ -298,7 +297,7 @@ static void free_channel_rcu(struct rcu_head *head)
        struct lttng_consumer_channel *channel =
                caa_container_of(node, struct lttng_consumer_channel, node);
 
-       switch (consumer_data.type) {
+       switch (the_consumer_data.type) {
        case LTTNG_CONSUMER_KERNEL:
                break;
        case LTTNG_CONSUMER32_UST:
@@ -352,7 +351,7 @@ void consumer_destroy_relayd(struct consumer_relayd_sock_pair *relayd)
        DBG("Consumer destroy and close relayd socket pair");
 
        iter.iter.node = &relayd->node.node;
-       ret = lttng_ht_del(consumer_data.relayd_ht, &iter);
+       ret = lttng_ht_del(the_consumer_data.relayd_ht, &iter);
        if (ret != 0) {
                /* We assume the relayd is being or is destroyed */
                return;
@@ -372,7 +371,7 @@ void consumer_del_channel(struct lttng_consumer_channel *channel)
 
        DBG("Consumer delete channel key %" PRIu64, channel->key);
 
-       pthread_mutex_lock(&consumer_data.lock);
+       pthread_mutex_lock(&the_consumer_data.lock);
        pthread_mutex_lock(&channel->lock);
 
        /* Destroy streams that might have been left in the stream list. */
@@ -385,7 +384,7 @@ void consumer_del_channel(struct lttng_consumer_channel *channel)
                consumer_timer_monitor_stop(channel);
        }
 
-       switch (consumer_data.type) {
+       switch (the_consumer_data.type) {
        case LTTNG_CONSUMER_KERNEL:
                break;
        case LTTNG_CONSUMER32_UST:
@@ -394,7 +393,7 @@ void consumer_del_channel(struct lttng_consumer_channel *channel)
                break;
        default:
                ERR("Unknown consumer_data type");
-               assert(0);
+               abort();
                goto end;
        }
 
@@ -406,13 +405,13 @@ void consumer_del_channel(struct lttng_consumer_channel *channel)
 
                rcu_read_lock();
                iter.iter.node = &channel->node.node;
-               ret = lttng_ht_del(consumer_data.channel_ht, &iter);
-               assert(!ret);
+               ret = lttng_ht_del(the_consumer_data.channel_ht, &iter);
+               LTTNG_ASSERT(!ret);
 
                iter.iter.node = &channel->channels_by_session_id_ht_node.node;
-               ret = lttng_ht_del(consumer_data.channels_by_session_id_ht,
+               ret = lttng_ht_del(the_consumer_data.channels_by_session_id_ht,
                                &iter);
-               assert(!ret);
+               LTTNG_ASSERT(!ret);
                rcu_read_unlock();
        }
 
@@ -420,7 +419,7 @@ void consumer_del_channel(struct lttng_consumer_channel *channel)
        call_rcu(&channel->node.head, free_channel_rcu);
 end:
        pthread_mutex_unlock(&channel->lock);
-       pthread_mutex_unlock(&consumer_data.lock);
+       pthread_mutex_unlock(&the_consumer_data.lock);
 }
 
 /*
@@ -434,14 +433,14 @@ static void cleanup_relayd_ht(void)
 
        rcu_read_lock();
 
-       cds_lfht_for_each_entry(consumer_data.relayd_ht->ht, &iter.iter, relayd,
-                       node.node) {
+       cds_lfht_for_each_entry(the_consumer_data.relayd_ht->ht, &iter.iter,
+                       relayd, node.node) {
                consumer_destroy_relayd(relayd);
        }
 
        rcu_read_unlock();
 
-       lttng_ht_destroy(consumer_data.relayd_ht);
+       lttng_ht_destroy(the_consumer_data.relayd_ht);
 }
 
 /*
@@ -491,7 +490,7 @@ void lttng_consumer_cleanup_relayd(struct consumer_relayd_sock_pair *relayd)
 {
        uint64_t netidx;
 
-       assert(relayd);
+       LTTNG_ASSERT(relayd);
 
        DBG("Cleaning up relayd object ID %"PRIu64, relayd->net_seq_idx);
 
@@ -525,7 +524,7 @@ void lttng_consumer_cleanup_relayd(struct consumer_relayd_sock_pair *relayd)
  */
 void consumer_flag_relayd_for_destroy(struct consumer_relayd_sock_pair *relayd)
 {
-       assert(relayd);
+       LTTNG_ASSERT(relayd);
 
        /* Set destroy flag for this object */
        uatomic_set(&relayd->destroy_flag, 1);
@@ -576,12 +575,12 @@ void consumer_add_data_stream(struct lttng_consumer_stream *stream)
 {
        struct lttng_ht *ht = data_ht;
 
-       assert(stream);
-       assert(ht);
+       LTTNG_ASSERT(stream);
+       LTTNG_ASSERT(ht);
 
        DBG3("Adding consumer stream %" PRIu64, stream->key);
 
-       pthread_mutex_lock(&consumer_data.lock);
+       pthread_mutex_lock(&the_consumer_data.lock);
        pthread_mutex_lock(&stream->chan->lock);
        pthread_mutex_lock(&stream->chan->timer_lock);
        pthread_mutex_lock(&stream->lock);
@@ -592,7 +591,7 @@ void consumer_add_data_stream(struct lttng_consumer_stream *stream)
 
        lttng_ht_add_unique_u64(ht, &stream->node);
 
-       lttng_ht_add_u64(consumer_data.stream_per_chan_id_ht,
+       lttng_ht_add_u64(the_consumer_data.stream_per_chan_id_ht,
                        &stream->node_channel_id);
 
        /*
@@ -600,7 +599,8 @@ void consumer_add_data_stream(struct lttng_consumer_stream *stream)
         * the key since the HT does not use it and we allow to add redundant keys
         * into this table.
         */
-       lttng_ht_add_u64(consumer_data.stream_list_ht, &stream->node_session_id);
+       lttng_ht_add_u64(the_consumer_data.stream_list_ht,
+                       &stream->node_session_id);
 
        /*
         * When nb_init_stream_left reaches 0, we don't need to trigger any action
@@ -616,14 +616,14 @@ void consumer_add_data_stream(struct lttng_consumer_stream *stream)
        }
 
        /* Update consumer data once the node is inserted. */
-       consumer_data.stream_count++;
-       consumer_data.need_update = 1;
+       the_consumer_data.stream_count++;
+       the_consumer_data.need_update = 1;
 
        rcu_read_unlock();
        pthread_mutex_unlock(&stream->lock);
        pthread_mutex_unlock(&stream->chan->timer_lock);
        pthread_mutex_unlock(&stream->chan->lock);
-       pthread_mutex_unlock(&consumer_data.lock);
+       pthread_mutex_unlock(&the_consumer_data.lock);
 }
 
 /*
@@ -636,15 +636,15 @@ static int add_relayd(struct consumer_relayd_sock_pair *relayd)
        struct lttng_ht_node_u64 *node;
        struct lttng_ht_iter iter;
 
-       assert(relayd);
+       LTTNG_ASSERT(relayd);
 
-       lttng_ht_lookup(consumer_data.relayd_ht,
-                       &relayd->net_seq_idx, &iter);
+       lttng_ht_lookup(the_consumer_data.relayd_ht, &relayd->net_seq_idx,
+                       &iter);
        node = lttng_ht_iter_get_node_u64(&iter);
        if (node != NULL) {
                goto end;
        }
-       lttng_ht_add_unique_u64(consumer_data.relayd_ht, &relayd->node);
+       lttng_ht_add_unique_u64(the_consumer_data.relayd_ht, &relayd->node);
 
 end:
        return ret;
@@ -699,8 +699,7 @@ struct consumer_relayd_sock_pair *consumer_find_relayd(uint64_t key)
                goto error;
        }
 
-       lttng_ht_lookup(consumer_data.relayd_ht, &key,
-                       &iter);
+       lttng_ht_lookup(the_consumer_data.relayd_ht, &key, &iter);
        node = lttng_ht_iter_get_node_u64(&iter);
        if (node != NULL) {
                relayd = caa_container_of(node, struct consumer_relayd_sock_pair, node);
@@ -721,9 +720,9 @@ int consumer_send_relayd_stream(struct lttng_consumer_stream *stream,
        int ret = 0;
        struct consumer_relayd_sock_pair *relayd;
 
-       assert(stream);
-       assert(stream->net_seq_idx != -1ULL);
-       assert(path);
+       LTTNG_ASSERT(stream);
+       LTTNG_ASSERT(stream->net_seq_idx != -1ULL);
+       LTTNG_ASSERT(path);
 
        /* The stream is not metadata. Get relayd reference if exists. */
        rcu_read_lock();
@@ -770,7 +769,7 @@ int consumer_send_relayd_streams_sent(uint64_t net_seq_idx)
        int ret = 0;
        struct consumer_relayd_sock_pair *relayd;
 
-       assert(net_seq_idx != -1ULL);
+       LTTNG_ASSERT(net_seq_idx != -1ULL);
 
        /* The stream is not metadata. Get relayd reference if exists. */
        rcu_read_lock();
@@ -830,8 +829,8 @@ static int write_relayd_stream_header(struct lttng_consumer_stream *stream,
        struct lttcomm_relayd_data_hdr data_hdr;
 
        /* Safety net */
-       assert(stream);
-       assert(relayd);
+       LTTNG_ASSERT(stream);
+       LTTNG_ASSERT(relayd);
 
        /* Reset data header */
        memset(&data_hdr, 0, sizeof(data_hdr));
@@ -877,6 +876,43 @@ error:
        return outfd;
 }
 
+/*
+ * Write a character on the metadata poll pipe to wake the metadata thread.
+ * Returns 0 on success, -1 on error.
+ */
+int consumer_metadata_wakeup_pipe(const struct lttng_consumer_channel *channel)
+{
+       int ret = 0;
+
+       DBG("Waking up metadata poll thread (writing to pipe): channel name = '%s'",
+                       channel->name);
+       if (channel->monitor && channel->metadata_stream) {
+               const char dummy = 'c';
+               const ssize_t write_ret = lttng_write(
+                               channel->metadata_stream->ust_metadata_poll_pipe[1],
+                               &dummy, 1);
+
+               if (write_ret < 1) {
+                       if (errno == EWOULDBLOCK) {
+                               /*
+                                * This is fine, the metadata poll thread
+                                * is having a hard time keeping-up, but
+                                * it will eventually wake-up and consume
+                                * the available data.
+                                */
+                               ret = 0;
+                       } else {
+                               PERROR("Failed to write to UST metadata pipe while attempting to wake-up the metadata poll thread");
+                               ret = -1;
+                               goto end;
+                       }
+               }
+       }
+
+end:
+       return ret;
+}
+
 /*
  * Trigger a dump of the metadata content. Following/during the succesful
  * completion of this call, the metadata poll thread will start receiving
@@ -891,10 +927,10 @@ int consumer_metadata_stream_dump(struct lttng_consumer_stream *stream)
 
        ASSERT_LOCKED(stream->chan->lock);
        ASSERT_LOCKED(stream->lock);
-       assert(stream->metadata_flag);
-       assert(stream->chan->trace_chunk);
+       LTTNG_ASSERT(stream->metadata_flag);
+       LTTNG_ASSERT(stream->chan->trace_chunk);
 
-       switch (consumer_data.type) {
+       switch (the_consumer_data.type) {
        case LTTNG_CONSUMER_KERNEL:
                /*
                 * Reset the position of what has been read from the
@@ -947,7 +983,7 @@ int lttng_consumer_channel_set_trace_chunk(
                const bool acquired_reference = lttng_trace_chunk_get(
                                new_trace_chunk);
 
-               assert(acquired_reference);
+               LTTNG_ASSERT(acquired_reference);
        }
 
        lttng_trace_chunk_put(channel->trace_chunk);
@@ -984,7 +1020,7 @@ struct lttng_consumer_channel *consumer_allocate_channel(uint64_t key,
 
        if (chunk_id) {
                trace_chunk = lttng_trace_chunk_registry_find_chunk(
-                               consumer_data.chunk_registry, session_id,
+                               the_consumer_data.chunk_registry, session_id,
                                *chunk_id);
                if (!trace_chunk) {
                        ERR("Failed to find trace chunk reference during creation of channel");
@@ -1019,7 +1055,7 @@ struct lttng_consumer_channel *consumer_allocate_channel(uint64_t key,
                channel->output = CONSUMER_CHANNEL_MMAP;
                break;
        default:
-               assert(0);
+               abort();
                free(channel);
                channel = NULL;
                goto end;
@@ -1087,7 +1123,7 @@ error:
 int consumer_add_channel(struct lttng_consumer_channel *channel,
                struct lttng_consumer_local_data *ctx)
 {
-       pthread_mutex_lock(&consumer_data.lock);
+       pthread_mutex_lock(&the_consumer_data.lock);
        pthread_mutex_lock(&channel->lock);
        pthread_mutex_lock(&channel->timer_lock);
 
@@ -1099,15 +1135,15 @@ int consumer_add_channel(struct lttng_consumer_channel *channel,
        steal_channel_key(channel->key);
 
        rcu_read_lock();
-       lttng_ht_add_unique_u64(consumer_data.channel_ht, &channel->node);
-       lttng_ht_add_u64(consumer_data.channels_by_session_id_ht,
+       lttng_ht_add_unique_u64(the_consumer_data.channel_ht, &channel->node);
+       lttng_ht_add_u64(the_consumer_data.channels_by_session_id_ht,
                        &channel->channels_by_session_id_ht_node);
        rcu_read_unlock();
        channel->is_published = true;
 
        pthread_mutex_unlock(&channel->timer_lock);
        pthread_mutex_unlock(&channel->lock);
-       pthread_mutex_unlock(&consumer_data.lock);
+       pthread_mutex_unlock(&the_consumer_data.lock);
 
        if (channel->wait_fd != -1 && channel->type == CONSUMER_CHANNEL_TYPE_DATA) {
                notify_channel_pipe(ctx, channel, -1, CONSUMER_CHANNEL_ADD);
@@ -1131,10 +1167,10 @@ static int update_poll_array(struct lttng_consumer_local_data *ctx,
        struct lttng_ht_iter iter;
        struct lttng_consumer_stream *stream;
 
-       assert(ctx);
-       assert(ht);
-       assert(pollfd);
-       assert(local_stream);
+       LTTNG_ASSERT(ctx);
+       LTTNG_ASSERT(ht);
+       LTTNG_ASSERT(pollfd);
+       LTTNG_ASSERT(local_stream);
 
        DBG("Updating poll fd array");
        *nb_inactive_fd = 0;
@@ -1251,26 +1287,26 @@ void lttng_consumer_cleanup(void)
 
        rcu_read_lock();
 
-       cds_lfht_for_each_entry(consumer_data.channel_ht->ht, &iter.iter, channel,
-                       node.node) {
+       cds_lfht_for_each_entry(the_consumer_data.channel_ht->ht, &iter.iter,
+                       channel, node.node) {
                consumer_del_channel(channel);
        }
 
        rcu_read_unlock();
 
-       lttng_ht_destroy(consumer_data.channel_ht);
-       lttng_ht_destroy(consumer_data.channels_by_session_id_ht);
+       lttng_ht_destroy(the_consumer_data.channel_ht);
+       lttng_ht_destroy(the_consumer_data.channels_by_session_id_ht);
 
        cleanup_relayd_ht();
 
-       lttng_ht_destroy(consumer_data.stream_per_chan_id_ht);
+       lttng_ht_destroy(the_consumer_data.stream_per_chan_id_ht);
 
        /*
         * This HT contains streams that are freed by either the metadata thread or
         * the data thread so we do *nothing* on the hash table and simply destroy
         * it.
         */
-       lttng_ht_destroy(consumer_data.stream_list_ht);
+       lttng_ht_destroy(the_consumer_data.stream_list_ht);
 
        /*
         * Trace chunks in the registry may still exist if the session
@@ -1285,7 +1321,7 @@ void lttng_consumer_cleanup(void)
         * to hit.
         */
        trace_chunks_left = lttng_trace_chunk_registry_put_each_chunk(
-                       consumer_data.chunk_registry);
+                       the_consumer_data.chunk_registry);
        if (trace_chunks_left) {
                ERR("%u trace chunks are leaked by lttng-consumerd. "
                                "This can be caused by an internal error of the session daemon.",
@@ -1293,7 +1329,7 @@ void lttng_consumer_cleanup(void)
        }
        /* Run all callbacks freeing each chunk. */
        rcu_barrier();
-       lttng_trace_chunk_registry_destroy(consumer_data.chunk_registry);
+       lttng_trace_chunk_registry_destroy(the_consumer_data.chunk_registry);
 }
 
 /*
@@ -1384,9 +1420,9 @@ struct lttng_consumer_local_data *lttng_consumer_create(
        int ret;
        struct lttng_consumer_local_data *ctx;
 
-       assert(consumer_data.type == LTTNG_CONSUMER_UNKNOWN ||
-               consumer_data.type == type);
-       consumer_data.type = type;
+       LTTNG_ASSERT(the_consumer_data.type == LTTNG_CONSUMER_UNKNOWN ||
+                       the_consumer_data.type == type);
+       the_consumer_data.type = type;
 
        ctx = zmalloc(sizeof(struct lttng_consumer_local_data));
        if (ctx == NULL) {
@@ -1598,7 +1634,7 @@ ssize_t lttng_consumer_on_read_subbuffer_mmap(
 
        /* RCU lock for the relayd pointer */
        rcu_read_lock();
-       assert(stream->net_seq_idx != (uint64_t) -1ULL ||
+       LTTNG_ASSERT(stream->net_seq_idx != (uint64_t) -1ULL ||
                        stream->trace_chunk);
 
        /* Flag that the current stream if set for network streaming. */
@@ -1765,7 +1801,7 @@ ssize_t lttng_consumer_on_read_subbuffer_splice(
        int *splice_pipe;
        unsigned int relayd_hang_up = 0;
 
-       switch (consumer_data.type) {
+       switch (the_consumer_data.type) {
        case LTTNG_CONSUMER_KERNEL:
                break;
        case LTTNG_CONSUMER32_UST:
@@ -1774,7 +1810,7 @@ ssize_t lttng_consumer_on_read_subbuffer_splice(
                return -ENOSYS;
        default:
                ERR("Unknown consumer_data type");
-               assert(0);
+               abort();
        }
 
        /* RCU lock for the relayd pointer */
@@ -1969,7 +2005,7 @@ end:
  */
 int lttng_consumer_sample_snapshot_positions(struct lttng_consumer_stream *stream)
 {
-       switch (consumer_data.type) {
+       switch (the_consumer_data.type) {
        case LTTNG_CONSUMER_KERNEL:
                return lttng_kconsumer_sample_snapshot_positions(stream);
        case LTTNG_CONSUMER32_UST:
@@ -1977,7 +2013,7 @@ int lttng_consumer_sample_snapshot_positions(struct lttng_consumer_stream *strea
                return lttng_ustconsumer_sample_snapshot_positions(stream);
        default:
                ERR("Unknown consumer_data type");
-               assert(0);
+               abort();
                return -ENOSYS;
        }
 }
@@ -1988,7 +2024,7 @@ int lttng_consumer_sample_snapshot_positions(struct lttng_consumer_stream *strea
  */
 int lttng_consumer_take_snapshot(struct lttng_consumer_stream *stream)
 {
-       switch (consumer_data.type) {
+       switch (the_consumer_data.type) {
        case LTTNG_CONSUMER_KERNEL:
                return lttng_kconsumer_take_snapshot(stream);
        case LTTNG_CONSUMER32_UST:
@@ -1996,7 +2032,7 @@ int lttng_consumer_take_snapshot(struct lttng_consumer_stream *stream)
                return lttng_ustconsumer_take_snapshot(stream);
        default:
                ERR("Unknown consumer_data type");
-               assert(0);
+               abort();
                return -ENOSYS;
        }
 }
@@ -2009,7 +2045,7 @@ int lttng_consumer_take_snapshot(struct lttng_consumer_stream *stream)
 int lttng_consumer_get_produced_snapshot(struct lttng_consumer_stream *stream,
                unsigned long *pos)
 {
-       switch (consumer_data.type) {
+       switch (the_consumer_data.type) {
        case LTTNG_CONSUMER_KERNEL:
                return lttng_kconsumer_get_produced_snapshot(stream, pos);
        case LTTNG_CONSUMER32_UST:
@@ -2017,7 +2053,7 @@ int lttng_consumer_get_produced_snapshot(struct lttng_consumer_stream *stream,
                return lttng_ustconsumer_get_produced_snapshot(stream, pos);
        default:
                ERR("Unknown consumer_data type");
-               assert(0);
+               abort();
                return -ENOSYS;
        }
 }
@@ -2030,7 +2066,7 @@ int lttng_consumer_get_produced_snapshot(struct lttng_consumer_stream *stream,
 int lttng_consumer_get_consumed_snapshot(struct lttng_consumer_stream *stream,
                unsigned long *pos)
 {
-       switch (consumer_data.type) {
+       switch (the_consumer_data.type) {
        case LTTNG_CONSUMER_KERNEL:
                return lttng_kconsumer_get_consumed_snapshot(stream, pos);
        case LTTNG_CONSUMER32_UST:
@@ -2038,7 +2074,7 @@ int lttng_consumer_get_consumed_snapshot(struct lttng_consumer_stream *stream,
                return lttng_ustconsumer_get_consumed_snapshot(stream, pos);
        default:
                ERR("Unknown consumer_data type");
-               assert(0);
+               abort();
                return -ENOSYS;
        }
 }
@@ -2046,7 +2082,7 @@ int lttng_consumer_get_consumed_snapshot(struct lttng_consumer_stream *stream,
 int lttng_consumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                int sock, struct pollfd *consumer_sockpoll)
 {
-       switch (consumer_data.type) {
+       switch (the_consumer_data.type) {
        case LTTNG_CONSUMER_KERNEL:
                return lttng_kconsumer_recv_cmd(ctx, sock, consumer_sockpoll);
        case LTTNG_CONSUMER32_UST:
@@ -2054,7 +2090,7 @@ int lttng_consumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                return lttng_ustconsumer_recv_cmd(ctx, sock, consumer_sockpoll);
        default:
                ERR("Unknown consumer_data type");
-               assert(0);
+               abort();
                return -ENOSYS;
        }
 }
@@ -2062,7 +2098,7 @@ int lttng_consumer_recv_cmd(struct lttng_consumer_local_data *ctx,
 static
 void lttng_consumer_close_all_metadata(void)
 {
-       switch (consumer_data.type) {
+       switch (the_consumer_data.type) {
        case LTTNG_CONSUMER_KERNEL:
                /*
                 * The Kernel consumer has a different metadata scheme so we don't
@@ -2082,7 +2118,7 @@ void lttng_consumer_close_all_metadata(void)
                break;
        default:
                ERR("Unknown consumer_data type");
-               assert(0);
+               abort();
        }
 }
 
@@ -2095,16 +2131,16 @@ void consumer_del_metadata_stream(struct lttng_consumer_stream *stream,
        struct lttng_consumer_channel *channel = NULL;
        bool free_channel = false;
 
-       assert(stream);
+       LTTNG_ASSERT(stream);
        /*
         * This call should NEVER receive regular stream. It must always be
         * metadata stream and this is crucial for data structure synchronization.
         */
-       assert(stream->metadata_flag);
+       LTTNG_ASSERT(stream->metadata_flag);
 
        DBG3("Consumer delete metadata stream %d", stream->wait_fd);
 
-       pthread_mutex_lock(&consumer_data.lock);
+       pthread_mutex_lock(&the_consumer_data.lock);
        /*
         * Note that this assumes that a stream's channel is never changed and
         * that the stream's lock doesn't need to be taken to sample its
@@ -2146,7 +2182,7 @@ void consumer_del_metadata_stream(struct lttng_consumer_stream *stream,
        }
        pthread_mutex_unlock(&stream->lock);
        pthread_mutex_unlock(&channel->lock);
-       pthread_mutex_unlock(&consumer_data.lock);
+       pthread_mutex_unlock(&the_consumer_data.lock);
 
        if (free_channel) {
                consumer_del_channel(channel);
@@ -2167,12 +2203,12 @@ void consumer_add_metadata_stream(struct lttng_consumer_stream *stream)
        struct lttng_ht_iter iter;
        struct lttng_ht_node_u64 *node;
 
-       assert(stream);
-       assert(ht);
+       LTTNG_ASSERT(stream);
+       LTTNG_ASSERT(ht);
 
        DBG3("Adding metadata stream %" PRIu64 " to hash table", stream->key);
 
-       pthread_mutex_lock(&consumer_data.lock);
+       pthread_mutex_lock(&the_consumer_data.lock);
        pthread_mutex_lock(&stream->chan->lock);
        pthread_mutex_lock(&stream->chan->timer_lock);
        pthread_mutex_lock(&stream->lock);
@@ -2190,7 +2226,7 @@ void consumer_add_metadata_stream(struct lttng_consumer_stream *stream)
         */
        lttng_ht_lookup(ht, &stream->key, &iter);
        node = lttng_ht_iter_get_node_u64(&iter);
-       assert(!node);
+       LTTNG_ASSERT(!node);
 
        /*
         * When nb_init_stream_left reaches 0, we don't need to trigger any action
@@ -2207,22 +2243,23 @@ void consumer_add_metadata_stream(struct lttng_consumer_stream *stream)
 
        lttng_ht_add_unique_u64(ht, &stream->node);
 
-       lttng_ht_add_u64(consumer_data.stream_per_chan_id_ht,
-               &stream->node_channel_id);
+       lttng_ht_add_u64(the_consumer_data.stream_per_chan_id_ht,
+                       &stream->node_channel_id);
 
        /*
         * Add stream to the stream_list_ht of the consumer data. No need to steal
         * the key since the HT does not use it and we allow to add redundant keys
         * into this table.
         */
-       lttng_ht_add_u64(consumer_data.stream_list_ht, &stream->node_session_id);
+       lttng_ht_add_u64(the_consumer_data.stream_list_ht,
+                       &stream->node_session_id);
 
        rcu_read_unlock();
 
        pthread_mutex_unlock(&stream->lock);
        pthread_mutex_unlock(&stream->chan->lock);
        pthread_mutex_unlock(&stream->chan->timer_lock);
-       pthread_mutex_unlock(&consumer_data.lock);
+       pthread_mutex_unlock(&the_consumer_data.lock);
 }
 
 /*
@@ -2258,7 +2295,7 @@ static void validate_endpoint_status_metadata_stream(
 
        DBG("Consumer delete flagged metadata stream");
 
-       assert(pollset);
+       LTTNG_ASSERT(pollset);
 
        rcu_read_lock();
        cds_lfht_for_each_entry(metadata_ht->ht, &iter.iter, stream, node.node) {
@@ -2410,7 +2447,7 @@ restart:
                                lttng_ht_lookup(metadata_ht, &tmp_id, &iter);
                        }
                        node = lttng_ht_iter_get_node_u64(&iter);
-                       assert(node);
+                       LTTNG_ASSERT(node);
 
                        stream = caa_container_of(node, struct lttng_consumer_stream,
                                        node);
@@ -2418,7 +2455,7 @@ restart:
                        if (revents & (LPOLLIN | LPOLLPRI)) {
                                /* Get the data out of the metadata file descriptor */
                                DBG("Metadata available on fd %d", pollfd);
-                               assert(stream->wait_fd == pollfd);
+                               LTTNG_ASSERT(stream->wait_fd == pollfd);
 
                                do {
                                        health_code_update();
@@ -2440,9 +2477,10 @@ restart:
                                }
                        } else if (revents & (LPOLLERR | LPOLLHUP)) {
                                DBG("Metadata fd %d is hup|err.", pollfd);
-                               if (!stream->hangup_flush_done
-                                               && (consumer_data.type == LTTNG_CONSUMER32_UST
-                                                       || consumer_data.type == LTTNG_CONSUMER64_UST)) {
+                               if (!stream->hangup_flush_done &&
+                                               (the_consumer_data.type == LTTNG_CONSUMER32_UST ||
+                                                               the_consumer_data.type ==
+                                                                               LTTNG_CONSUMER64_UST)) {
                                        DBG("Attempting to flush and consume the UST buffers");
                                        lttng_ustconsumer_on_stream_hangup(stream);
 
@@ -2538,8 +2576,8 @@ void *consumer_thread_data_poll(void *data)
                 * the fds set has been updated, we need to update our
                 * local array as well
                 */
-               pthread_mutex_lock(&consumer_data.lock);
-               if (consumer_data.need_update) {
+               pthread_mutex_lock(&the_consumer_data.lock);
+               if (the_consumer_data.need_update) {
                        free(pollfd);
                        pollfd = NULL;
 
@@ -2547,18 +2585,21 @@ void *consumer_thread_data_poll(void *data)
                        local_stream = NULL;
 
                        /* Allocate for all fds */
-                       pollfd = zmalloc((consumer_data.stream_count + nb_pipes_fd) * sizeof(struct pollfd));
+                       pollfd = zmalloc((the_consumer_data.stream_count +
+                                                        nb_pipes_fd) *
+                                       sizeof(struct pollfd));
                        if (pollfd == NULL) {
                                PERROR("pollfd malloc");
-                               pthread_mutex_unlock(&consumer_data.lock);
+                               pthread_mutex_unlock(&the_consumer_data.lock);
                                goto end;
                        }
 
-                       local_stream = zmalloc((consumer_data.stream_count + nb_pipes_fd) *
+                       local_stream = zmalloc((the_consumer_data.stream_count +
+                                                              nb_pipes_fd) *
                                        sizeof(struct lttng_consumer_stream *));
                        if (local_stream == NULL) {
                                PERROR("local_stream malloc");
-                               pthread_mutex_unlock(&consumer_data.lock);
+                               pthread_mutex_unlock(&the_consumer_data.lock);
                                goto end;
                        }
                        ret = update_poll_array(ctx, &pollfd, local_stream,
@@ -2566,13 +2607,13 @@ void *consumer_thread_data_poll(void *data)
                        if (ret < 0) {
                                ERR("Error in allocating pollfd or local_outfds");
                                lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_POLL_ERROR);
-                               pthread_mutex_unlock(&consumer_data.lock);
+                               pthread_mutex_unlock(&the_consumer_data.lock);
                                goto end;
                        }
                        nb_fd = ret;
-                       consumer_data.need_update = 0;
+                       the_consumer_data.need_update = 0;
                }
-               pthread_mutex_unlock(&consumer_data.lock);
+               pthread_mutex_unlock(&the_consumer_data.lock);
 
                /* No FDs and consumer_quit, consumer_cleanup the thread */
                if (nb_fd == 0 && nb_inactive_fd == 0 &&
@@ -2718,8 +2759,8 @@ void *consumer_thread_data_poll(void *data)
                        }
                        if (!local_stream[i]->hangup_flush_done
                                        && (pollfd[i].revents & (POLLHUP | POLLERR | POLLNVAL))
-                                       && (consumer_data.type == LTTNG_CONSUMER32_UST
-                                               || consumer_data.type == LTTNG_CONSUMER64_UST)) {
+                                       && (the_consumer_data.type == LTTNG_CONSUMER32_UST
+                                               || the_consumer_data.type == LTTNG_CONSUMER64_UST)) {
                                DBG("fd %d is hup|err|nval. Attempting flush and read.",
                                                pollfd[i].fd);
                                lttng_ustconsumer_on_stream_hangup(local_stream[i]);
@@ -2798,7 +2839,7 @@ void consumer_close_channel_streams(struct lttng_consumer_channel *channel)
        struct lttng_consumer_stream *stream;
        struct lttng_ht_iter iter;
 
-       ht = consumer_data.stream_per_chan_id_ht;
+       ht = the_consumer_data.stream_per_chan_id_ht;
 
        rcu_read_lock();
        cds_lfht_for_each_entry_duplicate(ht->ht,
@@ -2812,7 +2853,7 @@ void consumer_close_channel_streams(struct lttng_consumer_channel *channel)
                if (cds_lfht_is_node_deleted(&stream->node.node)) {
                        goto next;
                }
-               switch (consumer_data.type) {
+               switch (the_consumer_data.type) {
                case LTTNG_CONSUMER_KERNEL:
                        break;
                case LTTNG_CONSUMER32_UST:
@@ -2831,7 +2872,7 @@ void consumer_close_channel_streams(struct lttng_consumer_channel *channel)
                        break;
                default:
                        ERR("Unknown consumer_data type");
-                       assert(0);
+                       abort();
                }
        next:
                pthread_mutex_unlock(&stream->lock);
@@ -2852,7 +2893,7 @@ static void destroy_channel_ht(struct lttng_ht *ht)
        rcu_read_lock();
        cds_lfht_for_each_entry(ht->ht, &iter.iter, channel, wait_fd_node.node) {
                ret = lttng_ht_del(ht, &iter);
-               assert(ret != 0);
+               LTTNG_ASSERT(ret != 0);
        }
        rcu_read_unlock();
 
@@ -2990,9 +3031,9 @@ restart:
                                                lttng_poll_del(&events, chan->wait_fd);
                                                iter.iter.node = &chan->wait_fd_node.node;
                                                ret = lttng_ht_del(channel_ht, &iter);
-                                               assert(ret == 0);
+                                               LTTNG_ASSERT(ret == 0);
 
-                                               switch (consumer_data.type) {
+                                               switch (the_consumer_data.type) {
                                                case LTTNG_CONSUMER_KERNEL:
                                                        break;
                                                case LTTNG_CONSUMER32_UST:
@@ -3003,7 +3044,7 @@ restart:
                                                        break;
                                                default:
                                                        ERR("Unknown consumer_data type");
-                                                       assert(0);
+                                                       abort();
                                                }
 
                                                /*
@@ -3051,7 +3092,7 @@ restart:
                                lttng_ht_lookup(channel_ht, &tmp_id, &iter);
                        }
                        node = lttng_ht_iter_get_node_u64(&iter);
-                       assert(node);
+                       LTTNG_ASSERT(node);
 
                        chan = caa_container_of(node, struct lttng_consumer_channel,
                                        wait_fd_node);
@@ -3062,7 +3103,7 @@ restart:
 
                                lttng_poll_del(&events, chan->wait_fd);
                                ret = lttng_ht_del(channel_ht, &iter);
-                               assert(ret == 0);
+                               LTTNG_ASSERT(ret == 0);
 
                                /*
                                 * This will close the wait fd for each stream associated to
@@ -3110,8 +3151,8 @@ static int set_metadata_socket(struct lttng_consumer_local_data *ctx,
 {
        int ret;
 
-       assert(ctx);
-       assert(sockpoll);
+       LTTNG_ASSERT(ctx);
+       LTTNG_ASSERT(sockpoll);
 
        ret = lttng_consumer_poll_socket(sockpoll);
        if (ret) {
@@ -3340,6 +3381,7 @@ ssize_t lttng_consumer_read_subbuffer(struct lttng_consumer_stream *stream,
        ssize_t ret, written_bytes = 0;
        int rotation_ret;
        struct stream_subbuffer subbuffer = {};
+       enum get_next_subbuffer_status get_next_status;
 
        if (!locked_by_caller) {
                stream->read_subbuffer_ops.lock(stream);
@@ -3365,14 +3407,20 @@ ssize_t lttng_consumer_read_subbuffer(struct lttng_consumer_stream *stream,
                }
        }
 
-       ret = stream->read_subbuffer_ops.get_next_subbuffer(stream, &subbuffer);
-       if (ret) {
-               if (ret == -ENODATA) {
-                       /* Not an error. */
-                       ret = 0;
-                       goto sleep_stream;
-               }
+       get_next_status = stream->read_subbuffer_ops.get_next_subbuffer(
+                       stream, &subbuffer);
+       switch (get_next_status) {
+       case GET_NEXT_SUBBUFFER_STATUS_OK:
+               break;
+       case GET_NEXT_SUBBUFFER_STATUS_NO_DATA:
+               /* Not an error. */
+               ret = 0;
+               goto sleep_stream;
+       case GET_NEXT_SUBBUFFER_STATUS_ERROR:
+               ret = -1;
                goto end;
+       default:
+               abort();
        }
 
        ret = stream->read_subbuffer_ops.pre_consume_subbuffer(
@@ -3440,7 +3488,7 @@ error_put_subbuf:
 
 int lttng_consumer_on_recv_stream(struct lttng_consumer_stream *stream)
 {
-       switch (consumer_data.type) {
+       switch (the_consumer_data.type) {
        case LTTNG_CONSUMER_KERNEL:
                return lttng_kconsumer_on_recv_stream(stream);
        case LTTNG_CONSUMER32_UST:
@@ -3448,7 +3496,7 @@ int lttng_consumer_on_recv_stream(struct lttng_consumer_stream *stream)
                return lttng_ustconsumer_on_recv_stream(stream);
        default:
                ERR("Unknown consumer_data type");
-               assert(0);
+               abort();
                return -ENOSYS;
        }
 }
@@ -3458,29 +3506,30 @@ int lttng_consumer_on_recv_stream(struct lttng_consumer_stream *stream)
  */
 int lttng_consumer_init(void)
 {
-       consumer_data.channel_ht = lttng_ht_new(0, LTTNG_HT_TYPE_U64);
-       if (!consumer_data.channel_ht) {
+       the_consumer_data.channel_ht = lttng_ht_new(0, LTTNG_HT_TYPE_U64);
+       if (!the_consumer_data.channel_ht) {
                goto error;
        }
 
-       consumer_data.channels_by_session_id_ht =
+       the_consumer_data.channels_by_session_id_ht =
                        lttng_ht_new(0, LTTNG_HT_TYPE_U64);
-       if (!consumer_data.channels_by_session_id_ht) {
+       if (!the_consumer_data.channels_by_session_id_ht) {
                goto error;
        }
 
-       consumer_data.relayd_ht = lttng_ht_new(0, LTTNG_HT_TYPE_U64);
-       if (!consumer_data.relayd_ht) {
+       the_consumer_data.relayd_ht = lttng_ht_new(0, LTTNG_HT_TYPE_U64);
+       if (!the_consumer_data.relayd_ht) {
                goto error;
        }
 
-       consumer_data.stream_list_ht = lttng_ht_new(0, LTTNG_HT_TYPE_U64);
-       if (!consumer_data.stream_list_ht) {
+       the_consumer_data.stream_list_ht = lttng_ht_new(0, LTTNG_HT_TYPE_U64);
+       if (!the_consumer_data.stream_list_ht) {
                goto error;
        }
 
-       consumer_data.stream_per_chan_id_ht = lttng_ht_new(0, LTTNG_HT_TYPE_U64);
-       if (!consumer_data.stream_per_chan_id_ht) {
+       the_consumer_data.stream_per_chan_id_ht =
+                       lttng_ht_new(0, LTTNG_HT_TYPE_U64);
+       if (!the_consumer_data.stream_per_chan_id_ht) {
                goto error;
        }
 
@@ -3494,8 +3543,8 @@ int lttng_consumer_init(void)
                goto error;
        }
 
-       consumer_data.chunk_registry = lttng_trace_chunk_registry_create();
-       if (!consumer_data.chunk_registry) {
+       the_consumer_data.chunk_registry = lttng_trace_chunk_registry_create();
+       if (!the_consumer_data.chunk_registry) {
                goto error;
        }
 
@@ -3521,15 +3570,15 @@ error:
        enum lttcomm_return_code ret_code = LTTCOMM_CONSUMERD_SUCCESS;
        struct consumer_relayd_sock_pair *relayd = NULL;
 
-       assert(ctx);
-       assert(relayd_sock);
+       LTTNG_ASSERT(ctx);
+       LTTNG_ASSERT(relayd_sock);
 
        DBG("Consumer adding relayd socket (idx: %" PRIu64 ")", net_seq_idx);
 
        /* Get relayd reference if exists. */
        relayd = consumer_find_relayd(net_seq_idx);
        if (relayd == NULL) {
-               assert(sock_type == LTTNG_STREAM_CONTROL);
+               LTTNG_ASSERT(sock_type == LTTNG_STREAM_CONTROL);
                /* Not found. Allocate one. */
                relayd = consumer_allocate_relayd_sock_pair(net_seq_idx);
                if (relayd == NULL) {
@@ -3549,7 +3598,7 @@ error:
                /*
                 * relayd key should never be found for control socket.
                 */
-               assert(sock_type != LTTNG_STREAM_CONTROL);
+               LTTNG_ASSERT(sock_type != LTTNG_STREAM_CONTROL);
        }
 
        /* First send a status message before receiving the fds. */
@@ -3703,8 +3752,8 @@ static struct consumer_relayd_sock_pair *find_relayd_by_session_id(uint64_t id)
        struct consumer_relayd_sock_pair *relayd = NULL;
 
        /* Iterate over all relayd since they are indexed by net_seq_idx. */
-       cds_lfht_for_each_entry(consumer_data.relayd_ht->ht, &iter.iter, relayd,
-                       node.node) {
+       cds_lfht_for_each_entry(the_consumer_data.relayd_ht->ht, &iter.iter,
+                       relayd, node.node) {
                /*
                 * Check by sessiond id which is unique here where the relayd session
                 * id might not be when having multiple relayd.
@@ -3739,9 +3788,9 @@ int consumer_data_pending(uint64_t id)
        DBG("Consumer data pending command on session id %" PRIu64, id);
 
        rcu_read_lock();
-       pthread_mutex_lock(&consumer_data.lock);
+       pthread_mutex_lock(&the_consumer_data.lock);
 
-       switch (consumer_data.type) {
+       switch (the_consumer_data.type) {
        case LTTNG_CONSUMER_KERNEL:
                data_pending = lttng_kconsumer_data_pending;
                break;
@@ -3751,11 +3800,11 @@ int consumer_data_pending(uint64_t id)
                break;
        default:
                ERR("Unknown consumer data type");
-               assert(0);
+               abort();
        }
 
        /* Ease our life a bit */
-       ht = consumer_data.stream_list_ht;
+       ht = the_consumer_data.stream_list_ht;
 
        cds_lfht_for_each_entry_duplicate(ht->ht,
                        ht->hash_fct(&id, lttng_ht_seed),
@@ -3842,13 +3891,13 @@ int consumer_data_pending(uint64_t id)
 
 data_not_pending:
        /* Data is available to be read by a viewer. */
-       pthread_mutex_unlock(&consumer_data.lock);
+       pthread_mutex_unlock(&the_consumer_data.lock);
        rcu_read_unlock();
        return 0;
 
 data_pending:
        /* Data is still being extracted from buffers. */
-       pthread_mutex_unlock(&consumer_data.lock);
+       pthread_mutex_unlock(&the_consumer_data.lock);
        rcu_read_unlock();
        return 1;
 }
@@ -3878,7 +3927,7 @@ int consumer_send_status_channel(int sock,
 {
        struct lttcomm_consumer_status_channel msg;
 
-       assert(sock >= 0);
+       LTTNG_ASSERT(sock >= 0);
 
        memset(&msg, 0, sizeof(msg));
        if (!channel) {
@@ -3901,7 +3950,7 @@ unsigned long consumer_get_consume_start_pos(unsigned long consumed_pos,
        if (!nb_packets_per_stream) {
                return consumed_pos;    /* Grab everything */
        }
-       start_pos = produced_pos - offset_align_floor(produced_pos, max_sb_size);
+       start_pos = produced_pos - lttng_offset_align_floor(produced_pos, max_sb_size);
        start_pos -= max_sb_size * nb_packets_per_stream;
        if ((long) (start_pos - consumed_pos) < 0) {
                return consumed_pos;    /* Grab everything */
@@ -3909,6 +3958,36 @@ unsigned long consumer_get_consume_start_pos(unsigned long consumed_pos,
        return start_pos;
 }
 
+/* Stream lock must be held by the caller. */
+static int sample_stream_positions(struct lttng_consumer_stream *stream,
+                           unsigned long *produced, unsigned long *consumed)
+{
+       int ret;
+
+       ASSERT_LOCKED(stream->lock);
+
+       ret = lttng_consumer_sample_snapshot_positions(stream);
+       if (ret < 0) {
+               ERR("Failed to sample snapshot positions");
+               goto end;
+       }
+
+       ret = lttng_consumer_get_produced_snapshot(stream, produced);
+       if (ret < 0) {
+               ERR("Failed to sample produced position");
+               goto end;
+       }
+
+       ret = lttng_consumer_get_consumed_snapshot(stream, consumed);
+       if (ret < 0) {
+               ERR("Failed to sample consumed position");
+               goto end;
+       }
+
+end:
+       return ret;
+}
+
 /*
  * Sample the rotate position for all the streams of a channel. If a stream
  * is already at the rotate position (produced == consumed), we flag it as
@@ -3925,7 +4004,7 @@ int lttng_consumer_rotate_channel(struct lttng_consumer_channel *channel,
        int ret;
        struct lttng_consumer_stream *stream;
        struct lttng_ht_iter iter;
-       struct lttng_ht *ht = consumer_data.stream_per_chan_id_ht;
+       struct lttng_ht *ht = the_consumer_data.stream_per_chan_id_ht;
        struct lttng_dynamic_array stream_rotation_positions;
        uint64_t next_chunk_id, stream_count = 0;
        enum lttng_trace_chunk_status chunk_status;
@@ -3945,7 +4024,7 @@ int lttng_consumer_rotate_channel(struct lttng_consumer_channel *channel,
        rcu_read_lock();
 
        pthread_mutex_lock(&channel->lock);
-       assert(channel->trace_chunk);
+       LTTNG_ASSERT(channel->trace_chunk);
        chunk_status = lttng_trace_chunk_get_id(channel->trace_chunk,
                        &next_chunk_id);
        if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
@@ -3971,19 +4050,96 @@ int lttng_consumer_rotate_channel(struct lttng_consumer_channel *channel,
                }
 
                /*
-                * Do not flush an empty packet when rotating from a NULL trace
+                * Do not flush a packet when rotating from a NULL trace
                 * chunk. The stream has no means to output data, and the prior
-                * rotation which rotated to NULL performed that side-effect already.
+                * rotation which rotated to NULL performed that side-effect
+                * already. No new data can be produced when a stream has no
+                * associated trace chunk (e.g. a stop followed by a rotate).
                 */
                if (stream->trace_chunk) {
+                       bool flush_active;
+
+                       if (stream->metadata_flag) {
+                               /*
+                                * Don't produce an empty metadata packet,
+                                * simply close the current one.
+                                *
+                                * Metadata is regenerated on every trace chunk
+                                * switch; there is no concern that no data was
+                                * produced.
+                                */
+                               flush_active = true;
+                       } else {
+                               /*
+                                * Only flush an empty packet if the "packet
+                                * open" could not be performed on transition
+                                * to a new trace chunk and no packets were
+                                * consumed within the chunk's lifetime.
+                                */
+                               if (stream->opened_packet_in_current_trace_chunk) {
+                                       flush_active = true;
+                               } else {
+                                       /*
+                                        * Stream could have been full at the
+                                        * time of rotation, but then have had
+                                        * no activity at all.
+                                        *
+                                        * It is important to flush a packet
+                                        * to prevent 0-length files from being
+                                        * produced as most viewers choke on
+                                        * them.
+                                        *
+                                        * Unfortunately viewers will not be
+                                        * able to know that tracing was active
+                                        * for this stream during this trace
+                                        * chunk's lifetime.
+                                        */
+                                       ret = sample_stream_positions(stream, &produced_pos, &consumed_pos);
+                                       if (ret) {
+                                               goto end_unlock_stream;
+                                       }
+
+                                       /*
+                                        * Don't flush an empty packet if data
+                                        * was produced; it will be consumed
+                                        * before the rotation completes.
+                                        */
+                                       flush_active = produced_pos != consumed_pos;
+                                       if (!flush_active) {
+                                               const char *trace_chunk_name;
+                                               uint64_t trace_chunk_id;
+
+                                               chunk_status = lttng_trace_chunk_get_name(
+                                                               stream->trace_chunk,
+                                                               &trace_chunk_name,
+                                                               NULL);
+                                               if (chunk_status == LTTNG_TRACE_CHUNK_STATUS_NONE) {
+                                                       trace_chunk_name = "none";
+                                               }
+
+                                               /*
+                                                * Consumer trace chunks are
+                                                * never anonymous.
+                                                */
+                                               chunk_status = lttng_trace_chunk_get_id(
+                                                               stream->trace_chunk,
+                                                               &trace_chunk_id);
+                                               LTTNG_ASSERT(chunk_status ==
+                                                               LTTNG_TRACE_CHUNK_STATUS_OK);
+
+                                               DBG("Unable to open packet for stream during trace chunk's lifetime. "
+                                                               "Flushing an empty packet to prevent an empty file from being created: "
+                                                               "stream id = %" PRIu64 ", trace chunk name = `%s`, trace chunk id = %" PRIu64,
+                                                               stream->key, trace_chunk_name, trace_chunk_id);
+                                       }
+                               }
+                       }
+
                        /*
-                        * For metadata stream, do an active flush, which does not
-                        * produce empty packets. For data streams, empty-flush;
-                        * ensures we have at least one packet in each stream per trace
-                        * chunk, even if no data was produced.
+                        * Close the current packet before sampling the
+                        * ring buffer positions.
                         */
-                       ret = consumer_stream_flush_buffer(
-                                       stream, stream->metadata_flag ? 1 : 0);
+                       ret = consumer_stream_flush_buffer(stream, flush_active);
                        if (ret < 0) {
                                ERR("Failed to flush stream %" PRIu64 " during channel rotation",
                                                stream->key);
@@ -4015,7 +4171,7 @@ int lttng_consumer_rotate_channel(struct lttng_consumer_channel *channel,
                 * Align produced position on the start-of-packet boundary of the first
                 * packet going into the next trace chunk.
                 */
-               produced_pos = ALIGN_FLOOR(produced_pos, stream->max_sb_size);
+               produced_pos = lttng_align_floor(produced_pos, stream->max_sb_size);
                if (consumed_pos == produced_pos) {
                        DBG("Set rotate ready for stream %" PRIu64 " produced = %lu consumed = %lu",
                                        stream->key, produced_pos, consumed_pos);
@@ -4232,7 +4388,7 @@ int consumer_clear_buffer(struct lttng_consumer_stream *stream)
                goto end;
        }
 
-       switch (consumer_data.type) {
+       switch (the_consumer_data.type) {
        case LTTNG_CONSUMER_KERNEL:
                ret = kernctl_buffer_clear(stream->wait_fd);
                if (ret < 0) {
@@ -4242,7 +4398,11 @@ int consumer_clear_buffer(struct lttng_consumer_stream *stream)
                break;
        case LTTNG_CONSUMER32_UST:
        case LTTNG_CONSUMER64_UST:
-               lttng_ustconsumer_clear_buffer(stream);
+               ret = lttng_ustconsumer_clear_buffer(stream);
+               if (ret < 0) {
+                       ERR("Failed to clear ust stream (ret = %d)", ret);
+                       goto end;
+               }
                break;
        default:
                ERR("Unknown consumer_data type");
@@ -4512,7 +4672,7 @@ int lttng_consumer_rotate_ready_streams(struct lttng_consumer_channel *channel,
        int ret;
        struct lttng_consumer_stream *stream;
        struct lttng_ht_iter iter;
-       struct lttng_ht *ht = consumer_data.stream_per_chan_id_ht;
+       struct lttng_ht *ht = the_consumer_data.stream_per_chan_id_ht;
 
        rcu_read_lock();
 
@@ -4598,10 +4758,10 @@ enum lttcomm_return_code lttng_consumer_create_trace_chunk(
                } else {
                        relayd_id_str = "(formatting error)";
                }
-        }
+       }
 
-        /* Local protocol error. */
-       assert(chunk_creation_timestamp);
+       /* Local protocol error. */
+       LTTNG_ASSERT(chunk_creation_timestamp);
        ret = time_to_iso8601_str(chunk_creation_timestamp,
                        creation_timestamp_buffer,
                        sizeof(creation_timestamp_buffer));
@@ -4670,7 +4830,7 @@ enum lttcomm_return_code lttng_consumer_create_trace_chunk(
        }
 
        published_chunk = lttng_trace_chunk_registry_publish_chunk(
-                       consumer_data.chunk_registry, session_id,
+                       the_consumer_data.chunk_registry, session_id,
                        created_chunk);
        lttng_trace_chunk_put(created_chunk);
        created_chunk = NULL;
@@ -4681,10 +4841,11 @@ enum lttcomm_return_code lttng_consumer_create_trace_chunk(
        }
 
        rcu_read_lock();
-       cds_lfht_for_each_entry_duplicate(consumer_data.channels_by_session_id_ht->ht,
-                       consumer_data.channels_by_session_id_ht->hash_fct(
+       cds_lfht_for_each_entry_duplicate(
+                       the_consumer_data.channels_by_session_id_ht->ht,
+                       the_consumer_data.channels_by_session_id_ht->hash_fct(
                                        &session_id, lttng_ht_seed),
-                       consumer_data.channels_by_session_id_ht->match_fct,
+                       the_consumer_data.channels_by_session_id_ht->match_fct,
                        &session_id, &iter.iter, channel,
                        channels_by_session_id_ht_node.node) {
                ret = lttng_consumer_channel_set_trace_chunk(channel,
@@ -4797,7 +4958,7 @@ enum lttcomm_return_code lttng_consumer_close_trace_chunk(
                        close_command_name);
 
        chunk = lttng_trace_chunk_registry_find_chunk(
-                       consumer_data.chunk_registry, session_id, chunk_id);
+                       the_consumer_data.chunk_registry, session_id, chunk_id);
        if (!chunk) {
                ERR("Failed to find chunk: session_id = %" PRIu64
                                ", chunk_id = %" PRIu64,
@@ -4828,7 +4989,7 @@ enum lttcomm_return_code lttng_consumer_close_trace_chunk(
         * current chunk found in the session's channels.
         */
        rcu_read_lock();
-       cds_lfht_for_each_entry(consumer_data.channel_ht->ht, &iter.iter,
+       cds_lfht_for_each_entry(the_consumer_data.channel_ht->ht, &iter.iter,
                        channel, node.node) {
                int ret;
 
@@ -4899,8 +5060,6 @@ enum lttcomm_return_code lttng_consumer_trace_chunk_exists(
        bool chunk_exists_local, chunk_exists_remote;
 
        if (relayd_id) {
-               int ret;
-
                /* Only used for logging purposes. */
                ret = snprintf(relayd_id_buffer, sizeof(relayd_id_buffer),
                                "%" PRIu64, *relayd_id);
@@ -4909,14 +5068,14 @@ enum lttcomm_return_code lttng_consumer_trace_chunk_exists(
                } else {
                        relayd_id_str = "(formatting error)";
                }
-        }
+       }
 
        DBG("Consumer trace chunk exists command: relayd_id = %s"
                        ", chunk_id = %" PRIu64, relayd_id_str,
                        chunk_id);
        ret = lttng_trace_chunk_registry_chunk_exists(
-                       consumer_data.chunk_registry, session_id,
-                       chunk_id, &chunk_exists_local);
+                       the_consumer_data.chunk_registry, session_id, chunk_id,
+                       &chunk_exists_local);
        if (ret) {
                /* Internal error. */
                ERR("Failed to query the existence of a trace chunk");
@@ -4971,7 +5130,7 @@ int consumer_clear_monitored_channel(struct lttng_consumer_channel *channel)
        struct lttng_ht_iter iter;
        int ret;
 
-       ht = consumer_data.stream_per_chan_id_ht;
+       ht = the_consumer_data.stream_per_chan_id_ht;
 
        rcu_read_lock();
        cds_lfht_for_each_entry_duplicate(ht->ht,
@@ -5093,3 +5252,8 @@ error_unlock:
        pthread_mutex_unlock(&stream->lock);
        goto end_rcu_unlock;
 }
+
+void lttng_consumer_sigbus_handle(void *addr)
+{
+       lttng_ustconsumer_sigbus_handle(addr);
+}
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