X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fcommon%2Fconsumer.c;h=8bcfa45ebd746fd6be782c6259790ba9391168f8;hp=80dedd5c6cfd057397eef3706ec62ef9717889e7;hb=9d0482e7fb70c4deaebe57872cbd75a6a1c213fb;hpb=1d76b9222464f9e10128ae867cd56a9317da5d65 diff --git a/src/common/consumer.c b/src/common/consumer.c index 80dedd5c6..b0b926bb0 100644 --- a/src/common/consumer.c +++ b/src/common/consumer.c @@ -1,23 +1,24 @@ /* * Copyright (C) 2011 - Julien Desfossez * Mathieu Desnoyers + * 2012 - David Goulet * - * This program is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public License - * as published by the Free Software Foundation; only version 2 - * of the License. + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License, version 2 only, + * as published by the Free Software Foundation. * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. + * This program is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. * - * You should have received a copy of the GNU General Public License - * along with this program; if not, write to the Free Software - * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. */ #define _GNU_SOURCE +#define _LGPL_SOURCE #include #include #include @@ -27,14 +28,26 @@ #include #include #include +#include +#include +#include #include +#include +#include +#include +#include #include +#include #include #include +#include #include +#include #include "consumer.h" +#include "consumer-stream.h" +#include "consumer-testpoint.h" struct lttng_consumer_global_data consumer_data = { .stream_count = 0, @@ -42,8 +55,17 @@ struct lttng_consumer_global_data consumer_data = { .type = LTTNG_CONSUMER_UNKNOWN, }; -/* timeout parameter, to control the polling thread grace period. */ -int consumer_poll_timeout = -1; +enum consumer_channel_action { + CONSUMER_CHANNEL_ADD, + CONSUMER_CHANNEL_DEL, + CONSUMER_CHANNEL_QUIT, +}; + +struct consumer_channel_msg { + enum consumer_channel_action action; + struct lttng_consumer_channel *chan; /* add */ + uint64_t key; /* del */ +}; /* * Flag to inform the polling thread to quit when all fd hung up. Updated by @@ -51,27 +73,132 @@ int consumer_poll_timeout = -1; * Also updated by the signal handler (consumer_should_exit()). Read by the * polling threads. */ -volatile int consumer_quit = 0; +volatile int consumer_quit; + +/* + * Global hash table containing respectively metadata and data streams. The + * stream element in this ht should only be updated by the metadata poll thread + * for the metadata and the data poll thread for the data. + */ +static struct lttng_ht *metadata_ht; +static struct lttng_ht *data_ht; + +/* + * Notify a thread lttng pipe to poll back again. This usually means that some + * global state has changed so we just send back the thread in a poll wait + * call. + */ +static void notify_thread_lttng_pipe(struct lttng_pipe *pipe) +{ + struct lttng_consumer_stream *null_stream = NULL; + + assert(pipe); + + (void) lttng_pipe_write(pipe, &null_stream, sizeof(null_stream)); +} + +static void notify_health_quit_pipe(int *pipe) +{ + ssize_t ret; + + ret = lttng_write(pipe[1], "4", 1); + if (ret < 1) { + PERROR("write consumer health quit"); + } +} + +static void notify_channel_pipe(struct lttng_consumer_local_data *ctx, + struct lttng_consumer_channel *chan, + uint64_t key, + enum consumer_channel_action action) +{ + struct consumer_channel_msg msg; + ssize_t ret; + + memset(&msg, 0, sizeof(msg)); + + msg.action = action; + msg.chan = chan; + msg.key = key; + ret = lttng_write(ctx->consumer_channel_pipe[1], &msg, sizeof(msg)); + if (ret < sizeof(msg)) { + PERROR("notify_channel_pipe write error"); + } +} + +void notify_thread_del_channel(struct lttng_consumer_local_data *ctx, + uint64_t key) +{ + notify_channel_pipe(ctx, NULL, key, CONSUMER_CHANNEL_DEL); +} + +static int read_channel_pipe(struct lttng_consumer_local_data *ctx, + struct lttng_consumer_channel **chan, + uint64_t *key, + enum consumer_channel_action *action) +{ + struct consumer_channel_msg msg; + ssize_t ret; + + ret = lttng_read(ctx->consumer_channel_pipe[0], &msg, sizeof(msg)); + if (ret < sizeof(msg)) { + ret = -1; + goto error; + } + *action = msg.action; + *chan = msg.chan; + *key = msg.key; +error: + return (int) ret; +} + +/* + * Cleanup the stream list of a channel. Those streams are not yet globally + * visible + */ +static void clean_channel_stream_list(struct lttng_consumer_channel *channel) +{ + struct lttng_consumer_stream *stream, *stmp; + + assert(channel); + + /* Delete streams that might have been left in the stream list. */ + cds_list_for_each_entry_safe(stream, stmp, &channel->streams.head, + send_node) { + cds_list_del(&stream->send_node); + /* + * Once a stream is added to this list, the buffers were created so we + * have a guarantee that this call will succeed. Setting the monitor + * mode to 0 so we don't lock nor try to delete the stream from the + * global hash table. + */ + stream->monitor = 0; + consumer_stream_destroy(stream, NULL); + } +} /* * Find a stream. The consumer_data.lock must be locked during this * call. */ -static struct lttng_consumer_stream *consumer_find_stream(int key) +static struct lttng_consumer_stream *find_stream(uint64_t key, + struct lttng_ht *ht) { struct lttng_ht_iter iter; - struct lttng_ht_node_ulong *node; + struct lttng_ht_node_u64 *node; struct lttng_consumer_stream *stream = NULL; - /* Negative keys are lookup failures */ - if (key < 0) + assert(ht); + + /* -1ULL keys are lookup failures */ + if (key == (uint64_t) -1ULL) { return NULL; + } rcu_read_lock(); - lttng_ht_lookup(consumer_data.stream_ht, (void *)((unsigned long) key), - &iter); - node = lttng_ht_iter_get_node_ulong(&iter); + lttng_ht_lookup(ht, &key, &iter); + node = lttng_ht_iter_get_node_u64(&iter); if (node != NULL) { stream = caa_container_of(node, struct lttng_consumer_stream, node); } @@ -81,368 +208,833 @@ static struct lttng_consumer_stream *consumer_find_stream(int key) return stream; } -static void consumer_steal_stream_key(int key) +static void steal_stream_key(uint64_t key, struct lttng_ht *ht) { struct lttng_consumer_stream *stream; - stream = consumer_find_stream(key); - if (stream) - stream->key = -1; + rcu_read_lock(); + stream = find_stream(key, ht); + if (stream) { + stream->key = (uint64_t) -1ULL; + /* + * We don't want the lookup to match, but we still need + * to iterate on this stream when iterating over the hash table. Just + * change the node key. + */ + stream->node.key = (uint64_t) -1ULL; + } + rcu_read_unlock(); } -static struct lttng_consumer_channel *consumer_find_channel(int key) +/* + * Return a channel object for the given key. + * + * RCU read side lock MUST be acquired before calling this function and + * protects the channel ptr. + */ +struct lttng_consumer_channel *consumer_find_channel(uint64_t key) { struct lttng_ht_iter iter; - struct lttng_ht_node_ulong *node; + struct lttng_ht_node_u64 *node; struct lttng_consumer_channel *channel = NULL; - /* Negative keys are lookup failures */ - if (key < 0) + /* -1ULL keys are lookup failures */ + if (key == (uint64_t) -1ULL) { return NULL; + } - rcu_read_lock(); - - lttng_ht_lookup(consumer_data.channel_ht, (void *)((unsigned long) key), - &iter); - node = lttng_ht_iter_get_node_ulong(&iter); + lttng_ht_lookup(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); } - rcu_read_unlock(); - return channel; } -static void consumer_steal_channel_key(int key) +/* + * There is a possibility that the consumer does not have enough time between + * the close of the channel on the session daemon and the cleanup in here thus + * once we have a channel add with an existing key, we know for sure that this + * channel will eventually get cleaned up by all streams being closed. + * + * This function just nullifies the already existing channel key. + */ +static void steal_channel_key(uint64_t key) { struct lttng_consumer_channel *channel; + rcu_read_lock(); channel = consumer_find_channel(key); - if (channel) - channel->key = -1; + if (channel) { + channel->key = (uint64_t) -1ULL; + /* + * We don't want the lookup to match, but we still need to iterate on + * this channel when iterating over the hash table. Just change the + * node key. + */ + channel->node.key = (uint64_t) -1ULL; + } + rcu_read_unlock(); +} + +static void free_channel_rcu(struct rcu_head *head) +{ + struct lttng_ht_node_u64 *node = + caa_container_of(head, struct lttng_ht_node_u64, head); + struct lttng_consumer_channel *channel = + caa_container_of(node, struct lttng_consumer_channel, node); + + free(channel); } /* - * Remove a stream from the global list protected by a mutex. This - * function is also responsible for freeing its data structures. + * RCU protected relayd socket pair free. */ -void consumer_del_stream(struct lttng_consumer_stream *stream) +static void free_relayd_rcu(struct rcu_head *head) { - int ret; - struct lttng_ht_iter iter; - struct lttng_consumer_channel *free_chan = NULL; + struct lttng_ht_node_u64 *node = + caa_container_of(head, struct lttng_ht_node_u64, head); + struct consumer_relayd_sock_pair *relayd = + caa_container_of(node, struct consumer_relayd_sock_pair, node); - pthread_mutex_lock(&consumer_data.lock); + /* + * Close all sockets. This is done in the call RCU since we don't want the + * socket fds to be reassigned thus potentially creating bad state of the + * relayd object. + * + * We do not have to lock the control socket mutex here since at this stage + * there is no one referencing to this relayd object. + */ + (void) relayd_close(&relayd->control_sock); + (void) relayd_close(&relayd->data_sock); - switch (consumer_data.type) { - case LTTNG_CONSUMER_KERNEL: - if (stream->mmap_base != NULL) { - ret = munmap(stream->mmap_base, stream->mmap_len); - if (ret != 0) { - perror("munmap"); - } - } - break; - case LTTNG_CONSUMER32_UST: - case LTTNG_CONSUMER64_UST: - lttng_ustconsumer_del_stream(stream); - break; - default: - ERR("Unknown consumer_data type"); - assert(0); - goto end; - } + free(relayd); +} - rcu_read_lock(); +/* + * Destroy and free relayd socket pair object. + */ +void consumer_destroy_relayd(struct consumer_relayd_sock_pair *relayd) +{ + int ret; + struct lttng_ht_iter iter; - /* Get stream node from hash table */ - lttng_ht_lookup(consumer_data.stream_ht, - (void *)((unsigned long) stream->key), &iter); - /* Remove stream node from hash table */ - ret = lttng_ht_del(consumer_data.stream_ht, &iter); - assert(!ret); + if (relayd == NULL) { + return; + } - rcu_read_unlock(); + DBG("Consumer destroy and close relayd socket pair"); - if (consumer_data.stream_count <= 0) { - goto end; - } - consumer_data.stream_count--; - if (!stream) { - goto end; - } - if (stream->out_fd >= 0) { - close(stream->out_fd); - } - if (stream->wait_fd >= 0 && !stream->wait_fd_is_copy) { - close(stream->wait_fd); - } - if (stream->shm_fd >= 0 && stream->wait_fd != stream->shm_fd) { - close(stream->shm_fd); + iter.iter.node = &relayd->node.node; + ret = lttng_ht_del(consumer_data.relayd_ht, &iter); + if (ret != 0) { + /* We assume the relayd is being or is destroyed */ + return; } - if (!--stream->chan->refcount) - free_chan = stream->chan; - free(stream); -end: - consumer_data.need_update = 1; - pthread_mutex_unlock(&consumer_data.lock); - if (free_chan) - consumer_del_channel(free_chan); + /* RCU free() call */ + call_rcu(&relayd->node.head, free_relayd_rcu); } -static void consumer_del_stream_rcu(struct rcu_head *head) +/* + * Remove a channel from the global list protected by a mutex. This function is + * also responsible for freeing its data structures. + */ +void consumer_del_channel(struct lttng_consumer_channel *channel) { - struct lttng_ht_node_ulong *node = - caa_container_of(head, struct lttng_ht_node_ulong, head); - struct lttng_consumer_stream *stream = - caa_container_of(node, struct lttng_consumer_stream, node); + int ret; + struct lttng_ht_iter iter; - consumer_del_stream(stream); -} + DBG("Consumer delete channel key %" PRIu64, channel->key); -struct lttng_consumer_stream *consumer_allocate_stream( - int channel_key, int stream_key, - int shm_fd, int wait_fd, - enum lttng_consumer_stream_state state, - uint64_t mmap_len, - enum lttng_event_output output, - const char *path_name, - uid_t uid, - gid_t gid) -{ - struct lttng_consumer_stream *stream; - int ret; + pthread_mutex_lock(&consumer_data.lock); + pthread_mutex_lock(&channel->lock); - stream = zmalloc(sizeof(*stream)); - if (stream == NULL) { - perror("malloc struct lttng_consumer_stream"); - goto end; - } - stream->chan = consumer_find_channel(channel_key); - if (!stream->chan) { - perror("Unable to find channel key"); - goto end; + /* Destroy streams that might have been left in the stream list. */ + clean_channel_stream_list(channel); + + if (channel->live_timer_enabled == 1) { + consumer_timer_live_stop(channel); } - stream->chan->refcount++; - stream->key = stream_key; - stream->shm_fd = shm_fd; - stream->wait_fd = wait_fd; - stream->out_fd = -1; - stream->out_fd_offset = 0; - stream->state = state; - stream->mmap_len = mmap_len; - stream->mmap_base = NULL; - stream->output = output; - stream->uid = uid; - stream->gid = gid; - strncpy(stream->path_name, path_name, PATH_MAX - 1); - stream->path_name[PATH_MAX - 1] = '\0'; - lttng_ht_node_init_ulong(&stream->node, stream->key); switch (consumer_data.type) { case LTTNG_CONSUMER_KERNEL: break; case LTTNG_CONSUMER32_UST: case LTTNG_CONSUMER64_UST: - stream->cpu = stream->chan->cpucount++; - ret = lttng_ustconsumer_allocate_stream(stream); - if (ret) { - free(stream); - return NULL; - } + lttng_ustconsumer_del_channel(channel); break; default: ERR("Unknown consumer_data type"); assert(0); goto end; } - DBG("Allocated stream %s (key %d, shm_fd %d, wait_fd %d, mmap_len %llu, out_fd %d)", - stream->path_name, stream->key, - stream->shm_fd, - stream->wait_fd, - (unsigned long long) stream->mmap_len, - stream->out_fd); + + rcu_read_lock(); + iter.iter.node = &channel->node.node; + ret = lttng_ht_del(consumer_data.channel_ht, &iter); + assert(!ret); + rcu_read_unlock(); + + call_rcu(&channel->node.head, free_channel_rcu); end: - return stream; + pthread_mutex_unlock(&channel->lock); + pthread_mutex_unlock(&consumer_data.lock); } /* - * Add a stream to the global list protected by a mutex. + * Iterate over the relayd hash table and destroy each element. Finally, + * destroy the whole hash table. */ -int consumer_add_stream(struct lttng_consumer_stream *stream) +static void cleanup_relayd_ht(void) { - int ret = 0; + struct lttng_ht_iter iter; + struct consumer_relayd_sock_pair *relayd; - pthread_mutex_lock(&consumer_data.lock); - /* Steal stream identifier, for UST */ - consumer_steal_stream_key(stream->key); rcu_read_lock(); - lttng_ht_add_unique_ulong(consumer_data.stream_ht, &stream->node); - rcu_read_unlock(); - consumer_data.stream_count++; - consumer_data.need_update = 1; - switch (consumer_data.type) { - case LTTNG_CONSUMER_KERNEL: - break; - case LTTNG_CONSUMER32_UST: - case LTTNG_CONSUMER64_UST: - /* Streams are in CPU number order (we rely on this) */ - stream->cpu = stream->chan->nr_streams++; - break; - default: - ERR("Unknown consumer_data type"); - assert(0); - goto end; + cds_lfht_for_each_entry(consumer_data.relayd_ht->ht, &iter.iter, relayd, + node.node) { + consumer_destroy_relayd(relayd); } -end: - pthread_mutex_unlock(&consumer_data.lock); - return ret; + rcu_read_unlock(); + + lttng_ht_destroy(consumer_data.relayd_ht); } /* - * Update a stream according to what we just received. + * Update the end point status of all streams having the given network sequence + * index (relayd index). + * + * It's atomically set without having the stream mutex locked which is fine + * because we handle the write/read race with a pipe wakeup for each thread. */ -void consumer_change_stream_state(int stream_key, - enum lttng_consumer_stream_state state) +static void update_endpoint_status_by_netidx(uint64_t net_seq_idx, + enum consumer_endpoint_status status) { + struct lttng_ht_iter iter; struct lttng_consumer_stream *stream; - pthread_mutex_lock(&consumer_data.lock); - stream = consumer_find_stream(stream_key); - if (stream) { - stream->state = state; + DBG("Consumer set delete flag on stream by idx %" PRIu64, net_seq_idx); + + rcu_read_lock(); + + /* Let's begin with metadata */ + cds_lfht_for_each_entry(metadata_ht->ht, &iter.iter, stream, node.node) { + if (stream->net_seq_idx == net_seq_idx) { + uatomic_set(&stream->endpoint_status, status); + DBG("Delete flag set to metadata stream %d", stream->wait_fd); + } } - consumer_data.need_update = 1; - pthread_mutex_unlock(&consumer_data.lock); + + /* Follow up by the data streams */ + cds_lfht_for_each_entry(data_ht->ht, &iter.iter, stream, node.node) { + if (stream->net_seq_idx == net_seq_idx) { + uatomic_set(&stream->endpoint_status, status); + DBG("Delete flag set to data stream %d", stream->wait_fd); + } + } + rcu_read_unlock(); } /* - * Remove a channel from the global list protected by a mutex. This - * function is also responsible for freeing its data structures. + * Cleanup a relayd object by flagging every associated streams for deletion, + * destroying the object meaning removing it from the relayd hash table, + * closing the sockets and freeing the memory in a RCU call. + * + * If a local data context is available, notify the threads that the streams' + * state have changed. */ -void consumer_del_channel(struct lttng_consumer_channel *channel) +static void cleanup_relayd(struct consumer_relayd_sock_pair *relayd, + struct lttng_consumer_local_data *ctx) { - int ret; - struct lttng_ht_iter iter; + uint64_t netidx; - pthread_mutex_lock(&consumer_data.lock); + assert(relayd); - switch (consumer_data.type) { - case LTTNG_CONSUMER_KERNEL: - break; - case LTTNG_CONSUMER32_UST: - case LTTNG_CONSUMER64_UST: - lttng_ustconsumer_del_channel(channel); - break; - default: - ERR("Unknown consumer_data type"); - assert(0); - goto end; - } + DBG("Cleaning up relayd sockets"); - rcu_read_lock(); + /* Save the net sequence index before destroying the object */ + netidx = relayd->net_seq_idx; - lttng_ht_lookup(consumer_data.channel_ht, - (void *)((unsigned long) channel->key), &iter); - ret = lttng_ht_del(consumer_data.channel_ht, &iter); - assert(!ret); + /* + * Delete the relayd from the relayd hash table, close the sockets and free + * the object in a RCU call. + */ + consumer_destroy_relayd(relayd); - rcu_read_unlock(); + /* Set inactive endpoint to all streams */ + update_endpoint_status_by_netidx(netidx, CONSUMER_ENDPOINT_INACTIVE); - if (channel->mmap_base != NULL) { - ret = munmap(channel->mmap_base, channel->mmap_len); - if (ret != 0) { - perror("munmap"); - } - } - if (channel->wait_fd >= 0 && !channel->wait_fd_is_copy) { - close(channel->wait_fd); + /* + * With a local data context, notify the threads that the streams' state + * have changed. The write() action on the pipe acts as an "implicit" + * memory barrier ordering the updates of the end point status from the + * read of this status which happens AFTER receiving this notify. + */ + if (ctx) { + notify_thread_lttng_pipe(ctx->consumer_data_pipe); + notify_thread_lttng_pipe(ctx->consumer_metadata_pipe); } - if (channel->shm_fd >= 0 && channel->wait_fd != channel->shm_fd) { - close(channel->shm_fd); +} + +/* + * Flag a relayd socket pair for destruction. Destroy it if the refcount + * reaches zero. + * + * RCU read side lock MUST be aquired before calling this function. + */ +void consumer_flag_relayd_for_destroy(struct consumer_relayd_sock_pair *relayd) +{ + assert(relayd); + + /* Set destroy flag for this object */ + uatomic_set(&relayd->destroy_flag, 1); + + /* Destroy the relayd if refcount is 0 */ + if (uatomic_read(&relayd->refcount) == 0) { + consumer_destroy_relayd(relayd); } - free(channel); -end: - pthread_mutex_unlock(&consumer_data.lock); } -static void consumer_del_channel_rcu(struct rcu_head *head) +/* + * Completly destroy stream from every visiable data structure and the given + * hash table if one. + * + * One this call returns, the stream object is not longer usable nor visible. + */ +void consumer_del_stream(struct lttng_consumer_stream *stream, + struct lttng_ht *ht) { - struct lttng_ht_node_ulong *node = - caa_container_of(head, struct lttng_ht_node_ulong, head); - struct lttng_consumer_channel *channel= - caa_container_of(node, struct lttng_consumer_channel, node); + consumer_stream_destroy(stream, ht); +} - consumer_del_channel(channel); +/* + * XXX naming of del vs destroy is all mixed up. + */ +void consumer_del_stream_for_data(struct lttng_consumer_stream *stream) +{ + consumer_stream_destroy(stream, data_ht); } -struct lttng_consumer_channel *consumer_allocate_channel( - int channel_key, - int shm_fd, int wait_fd, - uint64_t mmap_len, - uint64_t max_sb_size) +void consumer_del_stream_for_metadata(struct lttng_consumer_stream *stream) +{ + consumer_stream_destroy(stream, metadata_ht); +} + +struct lttng_consumer_stream *consumer_allocate_stream(uint64_t channel_key, + uint64_t stream_key, + enum lttng_consumer_stream_state state, + const char *channel_name, + uid_t uid, + gid_t gid, + uint64_t relayd_id, + uint64_t session_id, + int cpu, + int *alloc_ret, + enum consumer_channel_type type, + unsigned int monitor) { - struct lttng_consumer_channel *channel; int ret; + struct lttng_consumer_stream *stream; - channel = zmalloc(sizeof(*channel)); - if (channel == NULL) { - perror("malloc struct lttng_consumer_channel"); + stream = zmalloc(sizeof(*stream)); + if (stream == NULL) { + PERROR("malloc struct lttng_consumer_stream"); + ret = -ENOMEM; goto end; } - channel->key = channel_key; - channel->shm_fd = shm_fd; - channel->wait_fd = wait_fd; - channel->mmap_len = mmap_len; - channel->max_sb_size = max_sb_size; - channel->refcount = 0; - channel->nr_streams = 0; - lttng_ht_node_init_ulong(&channel->node, channel->key); - switch (consumer_data.type) { - case LTTNG_CONSUMER_KERNEL: - channel->mmap_base = NULL; - channel->mmap_len = 0; - break; - case LTTNG_CONSUMER32_UST: - case LTTNG_CONSUMER64_UST: - ret = lttng_ustconsumer_allocate_channel(channel); - if (ret) { - free(channel); - return NULL; + rcu_read_lock(); + + stream->key = stream_key; + stream->out_fd = -1; + stream->out_fd_offset = 0; + stream->output_written = 0; + stream->state = state; + stream->uid = uid; + stream->gid = gid; + stream->net_seq_idx = relayd_id; + stream->session_id = session_id; + stream->monitor = monitor; + stream->endpoint_status = CONSUMER_ENDPOINT_ACTIVE; + stream->index_fd = -1; + pthread_mutex_init(&stream->lock, NULL); + + /* If channel is the metadata, flag this stream as metadata. */ + if (type == CONSUMER_CHANNEL_TYPE_METADATA) { + stream->metadata_flag = 1; + /* Metadata is flat out. */ + strncpy(stream->name, DEFAULT_METADATA_NAME, sizeof(stream->name)); + /* Live rendez-vous point. */ + pthread_cond_init(&stream->metadata_rdv, NULL); + pthread_mutex_init(&stream->metadata_rdv_lock, NULL); + } else { + /* Format stream name to _ */ + ret = snprintf(stream->name, sizeof(stream->name), "%s_%d", + channel_name, cpu); + if (ret < 0) { + PERROR("snprintf stream name"); + goto error; + } + } + + /* Key is always the wait_fd for streams. */ + lttng_ht_node_init_u64(&stream->node, stream->key); + + /* Init node per channel id key */ + lttng_ht_node_init_u64(&stream->node_channel_id, channel_key); + + /* Init session id node with the stream session id */ + lttng_ht_node_init_u64(&stream->node_session_id, stream->session_id); + + DBG3("Allocated stream %s (key %" PRIu64 ", chan_key %" PRIu64 + " relayd_id %" PRIu64 ", session_id %" PRIu64, + stream->name, stream->key, channel_key, + stream->net_seq_idx, stream->session_id); + + rcu_read_unlock(); + return stream; + +error: + rcu_read_unlock(); + free(stream); +end: + if (alloc_ret) { + *alloc_ret = ret; + } + return NULL; +} + +/* + * Add a stream to the global list protected by a mutex. + */ +int consumer_add_data_stream(struct lttng_consumer_stream *stream) +{ + struct lttng_ht *ht = data_ht; + int ret = 0; + + assert(stream); + assert(ht); + + DBG3("Adding consumer stream %" PRIu64, stream->key); + + pthread_mutex_lock(&consumer_data.lock); + pthread_mutex_lock(&stream->chan->lock); + pthread_mutex_lock(&stream->chan->timer_lock); + pthread_mutex_lock(&stream->lock); + rcu_read_lock(); + + /* Steal stream identifier to avoid having streams with the same key */ + steal_stream_key(stream->key, ht); + + lttng_ht_add_unique_u64(ht, &stream->node); + + lttng_ht_add_u64(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); + + /* + * When nb_init_stream_left reaches 0, we don't need to trigger any action + * in terms of destroying the associated channel, because the action that + * causes the count to become 0 also causes a stream to be added. The + * channel deletion will thus be triggered by the following removal of this + * stream. + */ + if (uatomic_read(&stream->chan->nb_init_stream_left) > 0) { + /* Increment refcount before decrementing nb_init_stream_left */ + cmm_smp_wmb(); + uatomic_dec(&stream->chan->nb_init_stream_left); + } + + /* Update consumer data once the node is inserted. */ + consumer_data.stream_count++; + 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); + + return ret; +} + +void consumer_del_data_stream(struct lttng_consumer_stream *stream) +{ + consumer_del_stream(stream, data_ht); +} + +/* + * Add relayd socket to global consumer data hashtable. RCU read side lock MUST + * be acquired before calling this. + */ +static int add_relayd(struct consumer_relayd_sock_pair *relayd) +{ + int ret = 0; + struct lttng_ht_node_u64 *node; + struct lttng_ht_iter iter; + + assert(relayd); + + lttng_ht_lookup(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); + +end: + return ret; +} + +/* + * Allocate and return a consumer relayd socket. + */ +struct consumer_relayd_sock_pair *consumer_allocate_relayd_sock_pair( + uint64_t net_seq_idx) +{ + struct consumer_relayd_sock_pair *obj = NULL; + + /* net sequence index of -1 is a failure */ + if (net_seq_idx == (uint64_t) -1ULL) { + goto error; + } + + obj = zmalloc(sizeof(struct consumer_relayd_sock_pair)); + if (obj == NULL) { + PERROR("zmalloc relayd sock"); + goto error; + } + + obj->net_seq_idx = net_seq_idx; + obj->refcount = 0; + obj->destroy_flag = 0; + obj->control_sock.sock.fd = -1; + obj->data_sock.sock.fd = -1; + lttng_ht_node_init_u64(&obj->node, obj->net_seq_idx); + pthread_mutex_init(&obj->ctrl_sock_mutex, NULL); + +error: + return obj; +} + +/* + * Find a relayd socket pair in the global consumer data. + * + * Return the object if found else NULL. + * RCU read-side lock must be held across this call and while using the + * returned object. + */ +struct consumer_relayd_sock_pair *consumer_find_relayd(uint64_t key) +{ + struct lttng_ht_iter iter; + struct lttng_ht_node_u64 *node; + struct consumer_relayd_sock_pair *relayd = NULL; + + /* Negative keys are lookup failures */ + if (key == (uint64_t) -1ULL) { + goto error; + } + + lttng_ht_lookup(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); + } + +error: + return relayd; +} + +/* + * Find a relayd and send the stream + * + * Returns 0 on success, < 0 on error + */ +int consumer_send_relayd_stream(struct lttng_consumer_stream *stream, + char *path) +{ + int ret = 0; + struct consumer_relayd_sock_pair *relayd; + + assert(stream); + assert(stream->net_seq_idx != -1ULL); + assert(path); + + /* The stream is not metadata. Get relayd reference if exists. */ + rcu_read_lock(); + relayd = consumer_find_relayd(stream->net_seq_idx); + if (relayd != NULL) { + /* Add stream on the relayd */ + pthread_mutex_lock(&relayd->ctrl_sock_mutex); + ret = relayd_add_stream(&relayd->control_sock, stream->name, + path, &stream->relayd_stream_id, + stream->chan->tracefile_size, stream->chan->tracefile_count); + pthread_mutex_unlock(&relayd->ctrl_sock_mutex); + if (ret < 0) { + goto end; + } + + uatomic_inc(&relayd->refcount); + stream->sent_to_relayd = 1; + } else { + ERR("Stream %" PRIu64 " relayd ID %" PRIu64 " unknown. Can't send it.", + stream->key, stream->net_seq_idx); + ret = -1; + goto end; + } + + DBG("Stream %s with key %" PRIu64 " sent to relayd id %" PRIu64, + stream->name, stream->key, stream->net_seq_idx); + +end: + rcu_read_unlock(); + return ret; +} + +/* + * Find a relayd and send the streams sent message + * + * Returns 0 on success, < 0 on error + */ +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); + + /* The stream is not metadata. Get relayd reference if exists. */ + rcu_read_lock(); + relayd = consumer_find_relayd(net_seq_idx); + if (relayd != NULL) { + /* Add stream on the relayd */ + pthread_mutex_lock(&relayd->ctrl_sock_mutex); + ret = relayd_streams_sent(&relayd->control_sock); + pthread_mutex_unlock(&relayd->ctrl_sock_mutex); + if (ret < 0) { + goto end; + } + } else { + ERR("Relayd ID %" PRIu64 " unknown. Can't send streams_sent.", + net_seq_idx); + ret = -1; + goto end; + } + + ret = 0; + DBG("All streams sent relayd id %" PRIu64, net_seq_idx); + +end: + rcu_read_unlock(); + return ret; +} + +/* + * Find a relayd and close the stream + */ +void close_relayd_stream(struct lttng_consumer_stream *stream) +{ + struct consumer_relayd_sock_pair *relayd; + + /* The stream is not metadata. Get relayd reference if exists. */ + rcu_read_lock(); + relayd = consumer_find_relayd(stream->net_seq_idx); + if (relayd) { + consumer_stream_relayd_close(stream, relayd); + } + rcu_read_unlock(); +} + +/* + * Handle stream for relayd transmission if the stream applies for network + * streaming where the net sequence index is set. + * + * Return destination file descriptor or negative value on error. + */ +static int write_relayd_stream_header(struct lttng_consumer_stream *stream, + size_t data_size, unsigned long padding, + struct consumer_relayd_sock_pair *relayd) +{ + int outfd = -1, ret; + struct lttcomm_relayd_data_hdr data_hdr; + + /* Safety net */ + assert(stream); + assert(relayd); + + /* Reset data header */ + memset(&data_hdr, 0, sizeof(data_hdr)); + + if (stream->metadata_flag) { + /* Caller MUST acquire the relayd control socket lock */ + ret = relayd_send_metadata(&relayd->control_sock, data_size); + if (ret < 0) { + goto error; + } + + /* Metadata are always sent on the control socket. */ + outfd = relayd->control_sock.sock.fd; + } else { + /* Set header with stream information */ + data_hdr.stream_id = htobe64(stream->relayd_stream_id); + data_hdr.data_size = htobe32(data_size); + data_hdr.padding_size = htobe32(padding); + /* + * Note that net_seq_num below is assigned with the *current* value of + * next_net_seq_num and only after that the next_net_seq_num will be + * increment. This is why when issuing a command on the relayd using + * this next value, 1 should always be substracted in order to compare + * the last seen sequence number on the relayd side to the last sent. + */ + data_hdr.net_seq_num = htobe64(stream->next_net_seq_num); + /* Other fields are zeroed previously */ + + ret = relayd_send_data_hdr(&relayd->data_sock, &data_hdr, + sizeof(data_hdr)); + if (ret < 0) { + goto error; } + + ++stream->next_net_seq_num; + + /* Set to go on data socket */ + outfd = relayd->data_sock.sock.fd; + } + +error: + return outfd; +} + +/* + * Allocate and return a new lttng_consumer_channel object using the given key + * to initialize the hash table node. + * + * On error, return NULL. + */ +struct lttng_consumer_channel *consumer_allocate_channel(uint64_t key, + uint64_t session_id, + const char *pathname, + const char *name, + uid_t uid, + gid_t gid, + uint64_t relayd_id, + enum lttng_event_output output, + uint64_t tracefile_size, + uint64_t tracefile_count, + uint64_t session_id_per_pid, + unsigned int monitor, + unsigned int live_timer_interval) +{ + struct lttng_consumer_channel *channel; + + channel = zmalloc(sizeof(*channel)); + if (channel == NULL) { + PERROR("malloc struct lttng_consumer_channel"); + goto end; + } + + channel->key = key; + channel->refcount = 0; + channel->session_id = session_id; + channel->session_id_per_pid = session_id_per_pid; + channel->uid = uid; + channel->gid = gid; + channel->relayd_id = relayd_id; + channel->tracefile_size = tracefile_size; + channel->tracefile_count = tracefile_count; + channel->monitor = monitor; + channel->live_timer_interval = live_timer_interval; + pthread_mutex_init(&channel->lock, NULL); + pthread_mutex_init(&channel->timer_lock, NULL); + + switch (output) { + case LTTNG_EVENT_SPLICE: + channel->output = CONSUMER_CHANNEL_SPLICE; + break; + case LTTNG_EVENT_MMAP: + channel->output = CONSUMER_CHANNEL_MMAP; break; default: - ERR("Unknown consumer_data type"); assert(0); + free(channel); + channel = NULL; goto end; } - DBG("Allocated channel (key %d, shm_fd %d, wait_fd %d, mmap_len %llu, max_sb_size %llu)", - channel->key, - channel->shm_fd, - channel->wait_fd, - (unsigned long long) channel->mmap_len, - (unsigned long long) channel->max_sb_size); + + /* + * In monitor mode, the streams associated with the channel will be put in + * a special list ONLY owned by this channel. So, the refcount is set to 1 + * here meaning that the channel itself has streams that are referenced. + * + * On a channel deletion, once the channel is no longer visible, the + * refcount is decremented and checked for a zero value to delete it. With + * streams in no monitor mode, it will now be safe to destroy the channel. + */ + if (!channel->monitor) { + channel->refcount = 1; + } + + strncpy(channel->pathname, pathname, sizeof(channel->pathname)); + channel->pathname[sizeof(channel->pathname) - 1] = '\0'; + + strncpy(channel->name, name, sizeof(channel->name)); + channel->name[sizeof(channel->name) - 1] = '\0'; + + lttng_ht_node_init_u64(&channel->node, channel->key); + + channel->wait_fd = -1; + + CDS_INIT_LIST_HEAD(&channel->streams.head); + + DBG("Allocated channel (key %" PRIu64 ")", channel->key) + end: return channel; } /* * Add a channel to the global list protected by a mutex. + * + * Always return 0 indicating success. */ -int consumer_add_channel(struct lttng_consumer_channel *channel) +int consumer_add_channel(struct lttng_consumer_channel *channel, + struct lttng_consumer_local_data *ctx) { pthread_mutex_lock(&consumer_data.lock); - /* Steal channel identifier, for UST */ - consumer_steal_channel_key(channel->key); + pthread_mutex_lock(&channel->lock); + pthread_mutex_lock(&channel->timer_lock); + + /* + * This gives us a guarantee that the channel we are about to add to the + * channel hash table will be unique. See this function comment on the why + * we need to steel the channel key at this stage. + */ + steal_channel_key(channel->key); + rcu_read_lock(); - lttng_ht_add_unique_ulong(consumer_data.channel_ht, &channel->node); + lttng_ht_add_unique_u64(consumer_data.channel_ht, &channel->node); rcu_read_unlock(); + + pthread_mutex_unlock(&channel->timer_lock); + pthread_mutex_unlock(&channel->lock); pthread_mutex_unlock(&consumer_data.lock); + + if (channel->wait_fd != -1 && channel->type == CONSUMER_CHANNEL_TYPE_DATA) { + notify_channel_pipe(ctx, channel, -1, CONSUMER_CHANNEL_ADD); + } + return 0; } @@ -453,64 +1045,92 @@ int consumer_add_channel(struct lttng_consumer_channel *channel) * * Returns the number of fds in the structures. */ -int consumer_update_poll_array( - struct lttng_consumer_local_data *ctx, struct pollfd **pollfd, - struct lttng_consumer_stream **local_stream) +static int update_poll_array(struct lttng_consumer_local_data *ctx, + struct pollfd **pollfd, struct lttng_consumer_stream **local_stream, + struct lttng_ht *ht) { int i = 0; struct lttng_ht_iter iter; struct lttng_consumer_stream *stream; + assert(ctx); + assert(ht); + assert(pollfd); + assert(local_stream); + DBG("Updating poll fd array"); - cds_lfht_for_each_entry(consumer_data.stream_ht->ht, &iter.iter, stream, - node.node) { - if (stream->state != LTTNG_CONSUMER_ACTIVE_STREAM) { + rcu_read_lock(); + cds_lfht_for_each_entry(ht->ht, &iter.iter, stream, node.node) { + /* + * Only active streams with an active end point can be added to the + * poll set and local stream storage of the thread. + * + * There is a potential race here for endpoint_status to be updated + * just after the check. However, this is OK since the stream(s) will + * be deleted once the thread is notified that the end point state has + * changed where this function will be called back again. + */ + if (stream->state != LTTNG_CONSUMER_ACTIVE_STREAM || + stream->endpoint_status == CONSUMER_ENDPOINT_INACTIVE) { continue; } - DBG("Active FD %d", stream->wait_fd); + /* + * This clobbers way too much the debug output. Uncomment that if you + * need it for debugging purposes. + * + * DBG("Active FD %d", stream->wait_fd); + */ (*pollfd)[i].fd = stream->wait_fd; (*pollfd)[i].events = POLLIN | POLLPRI; local_stream[i] = stream; i++; } + rcu_read_unlock(); /* - * Insert the consumer_poll_pipe at the end of the array and don't + * Insert the consumer_data_pipe at the end of the array and don't * increment i so nb_fd is the number of real FD. */ - (*pollfd)[i].fd = ctx->consumer_poll_pipe[0]; - (*pollfd)[i].events = POLLIN; + (*pollfd)[i].fd = lttng_pipe_get_readfd(ctx->consumer_data_pipe); + (*pollfd)[i].events = POLLIN | POLLPRI; + + (*pollfd)[i + 1].fd = lttng_pipe_get_readfd(ctx->consumer_wakeup_pipe); + (*pollfd)[i + 1].events = POLLIN | POLLPRI; return i; } /* - * Poll on the should_quit pipe and the command socket return -1 on error and - * should exit, 0 if data is available on the command socket + * Poll on the should_quit pipe and the command socket return -1 on + * error, 1 if should exit, 0 if data is available on the command socket */ int lttng_consumer_poll_socket(struct pollfd *consumer_sockpoll) { int num_rdy; +restart: num_rdy = poll(consumer_sockpoll, 2, -1); if (num_rdy == -1) { - perror("Poll error"); - goto exit; + /* + * Restart interrupted system call. + */ + if (errno == EINTR) { + goto restart; + } + PERROR("Poll error"); + return -1; } - if (consumer_sockpoll[0].revents == POLLIN) { + if (consumer_sockpoll[0].revents & (POLLIN | POLLPRI)) { DBG("consumer_should_quit wake up"); - goto exit; + return 1; } return 0; - -exit: - return -1; } /* * Set the error socket. */ -void lttng_consumer_set_error_sock( - struct lttng_consumer_local_data *ctx, int sock) +void lttng_consumer_set_error_sock(struct lttng_consumer_local_data *ctx, + int sock) { ctx->consumer_error_socket = sock; } @@ -518,7 +1138,6 @@ void lttng_consumer_set_error_sock( /* * Set the command socket path. */ - void lttng_consumer_set_command_sock_path( struct lttng_consumer_local_data *ctx, char *sock) { @@ -529,8 +1148,7 @@ void lttng_consumer_set_command_sock_path( * Send return code to the session daemon. * If the socket is not defined, we return 0, it is not a fatal error */ -int lttng_consumer_send_error( - struct lttng_consumer_local_data *ctx, int cmd) +int lttng_consumer_send_error(struct lttng_consumer_local_data *ctx, int cmd) { if (ctx->consumer_error_socket > 0) { return lttcomm_send_unix_sock(ctx->consumer_error_socket, &cmd, @@ -541,36 +1159,35 @@ int lttng_consumer_send_error( } /* - * Close all the tracefiles and stream fds, should be called when all instances - * are destroyed. + * Close all the tracefiles and stream fds and MUST be called when all + * instances are destroyed i.e. when all threads were joined and are ended. */ void lttng_consumer_cleanup(void) { - int ret; struct lttng_ht_iter iter; - struct lttng_ht_node_ulong *node; + struct lttng_consumer_channel *channel; rcu_read_lock(); - /* - * close all outfd. Called when there are no more threads running (after - * joining on the threads), no need to protect list iteration with mutex. - */ - cds_lfht_for_each_entry(consumer_data.stream_ht->ht, &iter.iter, node, - node) { - ret = lttng_ht_del(consumer_data.stream_ht, &iter); - assert(!ret); - call_rcu(&node->head, consumer_del_stream_rcu); - } - - cds_lfht_for_each_entry(consumer_data.channel_ht->ht, &iter.iter, node, - node) { - ret = lttng_ht_del(consumer_data.channel_ht, &iter); - assert(!ret); - call_rcu(&node->head, consumer_del_channel_rcu); + cds_lfht_for_each_entry(consumer_data.channel_ht->ht, &iter.iter, channel, + node.node) { + consumer_del_channel(channel); } rcu_read_unlock(); + + lttng_ht_destroy(consumer_data.channel_ht); + + cleanup_relayd_ht(); + + lttng_ht_destroy(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); } /* @@ -578,16 +1195,19 @@ void lttng_consumer_cleanup(void) */ void lttng_consumer_should_exit(struct lttng_consumer_local_data *ctx) { - int ret; + ssize_t ret; + consumer_quit = 1; - ret = write(ctx->consumer_should_quit[1], "4", 1); - if (ret < 0) { - perror("write consumer quit"); + ret = lttng_write(ctx->consumer_should_quit[1], "4", 1); + if (ret < 1) { + PERROR("write consumer quit"); } + + DBG("Consumer flag that it should quit"); } -void lttng_consumer_sync_trace_file( - struct lttng_consumer_stream *stream, off_t orig_offset) +void lttng_consumer_sync_trace_file(struct lttng_consumer_stream *stream, + off_t orig_offset) { int outfd = stream->out_fd; @@ -597,11 +1217,11 @@ void lttng_consumer_sync_trace_file( * Don't care about error values, as these are just hints and ways to * limit the amount of page cache used. */ - if (orig_offset < stream->chan->max_sb_size) { + if (orig_offset < stream->max_sb_size) { return; } - lttng_sync_file_range(outfd, orig_offset - stream->chan->max_sb_size, - stream->chan->max_sb_size, + lttng_sync_file_range(outfd, orig_offset - stream->max_sb_size, + stream->max_sb_size, SYNC_FILE_RANGE_WAIT_BEFORE | SYNC_FILE_RANGE_WRITE | SYNC_FILE_RANGE_WAIT_AFTER); @@ -619,8 +1239,8 @@ void lttng_consumer_sync_trace_file( * defined. So it can be expected to lead to lower throughput in * streaming. */ - posix_fadvise(outfd, orig_offset - stream->chan->max_sb_size, - stream->chan->max_sb_size, POSIX_FADV_DONTNEED); + posix_fadvise(outfd, orig_offset - stream->max_sb_size, + stream->max_sb_size, POSIX_FADV_DONTNEED); } /* @@ -639,13 +1259,13 @@ void lttng_consumer_sync_trace_file( */ struct lttng_consumer_local_data *lttng_consumer_create( enum lttng_consumer_type type, - int (*buffer_ready)(struct lttng_consumer_stream *stream, + ssize_t (*buffer_ready)(struct lttng_consumer_stream *stream, struct lttng_consumer_local_data *ctx), int (*recv_channel)(struct lttng_consumer_channel *channel), int (*recv_stream)(struct lttng_consumer_stream *stream), - int (*update_stream)(int stream_key, uint32_t state)) + int (*update_stream)(uint64_t stream_key, uint32_t state)) { - int ret, i; + int ret; struct lttng_consumer_local_data *ctx; assert(consumer_data.type == LTTNG_CONSUMER_UNKNOWN || @@ -654,118 +1274,607 @@ struct lttng_consumer_local_data *lttng_consumer_create( ctx = zmalloc(sizeof(struct lttng_consumer_local_data)); if (ctx == NULL) { - perror("allocating context"); + PERROR("allocating context"); goto error; } ctx->consumer_error_socket = -1; + ctx->consumer_metadata_socket = -1; + pthread_mutex_init(&ctx->metadata_socket_lock, NULL); /* assign the callbacks */ ctx->on_buffer_ready = buffer_ready; ctx->on_recv_channel = recv_channel; ctx->on_recv_stream = recv_stream; ctx->on_update_stream = update_stream; - ret = pipe(ctx->consumer_poll_pipe); - if (ret < 0) { - perror("Error creating poll pipe"); + ctx->consumer_data_pipe = lttng_pipe_open(0); + if (!ctx->consumer_data_pipe) { goto error_poll_pipe; } + ctx->consumer_wakeup_pipe = lttng_pipe_open(0); + if (!ctx->consumer_wakeup_pipe) { + goto error_wakeup_pipe; + } + ret = pipe(ctx->consumer_should_quit); if (ret < 0) { - perror("Error creating recv pipe"); + PERROR("Error creating recv pipe"); goto error_quit_pipe; } - ret = pipe(ctx->consumer_thread_pipe); + ret = pipe(ctx->consumer_channel_pipe); if (ret < 0) { - perror("Error creating thread pipe"); - goto error_thread_pipe; + PERROR("Error creating channel pipe"); + goto error_channel_pipe; } - return ctx; - + ctx->consumer_metadata_pipe = lttng_pipe_open(0); + if (!ctx->consumer_metadata_pipe) { + goto error_metadata_pipe; + } -error_thread_pipe: - for (i = 0; i < 2; i++) { - int err; + return ctx; - err = close(ctx->consumer_should_quit[i]); - assert(!err); - } +error_metadata_pipe: + utils_close_pipe(ctx->consumer_channel_pipe); +error_channel_pipe: + utils_close_pipe(ctx->consumer_should_quit); error_quit_pipe: - for (i = 0; i < 2; i++) { - int err; - - err = close(ctx->consumer_poll_pipe[i]); - assert(!err); - } + lttng_pipe_destroy(ctx->consumer_wakeup_pipe); +error_wakeup_pipe: + lttng_pipe_destroy(ctx->consumer_data_pipe); error_poll_pipe: free(ctx); error: return NULL; } +/* + * Iterate over all streams of the hashtable and free them properly. + */ +static void destroy_data_stream_ht(struct lttng_ht *ht) +{ + struct lttng_ht_iter iter; + struct lttng_consumer_stream *stream; + + if (ht == NULL) { + return; + } + + rcu_read_lock(); + cds_lfht_for_each_entry(ht->ht, &iter.iter, stream, node.node) { + /* + * Ignore return value since we are currently cleaning up so any error + * can't be handled. + */ + (void) consumer_del_stream(stream, ht); + } + rcu_read_unlock(); + + lttng_ht_destroy(ht); +} + +/* + * Iterate over all streams of the metadata hashtable and free them + * properly. + */ +static void destroy_metadata_stream_ht(struct lttng_ht *ht) +{ + struct lttng_ht_iter iter; + struct lttng_consumer_stream *stream; + + if (ht == NULL) { + return; + } + + rcu_read_lock(); + cds_lfht_for_each_entry(ht->ht, &iter.iter, stream, node.node) { + /* + * Ignore return value since we are currently cleaning up so any error + * can't be handled. + */ + (void) consumer_del_metadata_stream(stream, ht); + } + rcu_read_unlock(); + + lttng_ht_destroy(ht); +} + /* * Close all fds associated with the instance and free the context. */ void lttng_consumer_destroy(struct lttng_consumer_local_data *ctx) { - close(ctx->consumer_error_socket); - close(ctx->consumer_thread_pipe[0]); - close(ctx->consumer_thread_pipe[1]); - close(ctx->consumer_poll_pipe[0]); - close(ctx->consumer_poll_pipe[1]); - close(ctx->consumer_should_quit[0]); - close(ctx->consumer_should_quit[1]); + int ret; + + DBG("Consumer destroying it. Closing everything."); + + if (!ctx) { + return; + } + + destroy_data_stream_ht(data_ht); + destroy_metadata_stream_ht(metadata_ht); + + ret = close(ctx->consumer_error_socket); + if (ret) { + PERROR("close"); + } + ret = close(ctx->consumer_metadata_socket); + if (ret) { + PERROR("close"); + } + utils_close_pipe(ctx->consumer_channel_pipe); + lttng_pipe_destroy(ctx->consumer_data_pipe); + lttng_pipe_destroy(ctx->consumer_metadata_pipe); + lttng_pipe_destroy(ctx->consumer_wakeup_pipe); + utils_close_pipe(ctx->consumer_should_quit); + unlink(ctx->consumer_command_sock_path); free(ctx); } /* - * Mmap the ring buffer, read it and write the data to the tracefile. + * Write the metadata stream id on the specified file descriptor. + */ +static int write_relayd_metadata_id(int fd, + struct lttng_consumer_stream *stream, + struct consumer_relayd_sock_pair *relayd, unsigned long padding) +{ + ssize_t ret; + struct lttcomm_relayd_metadata_payload hdr; + + hdr.stream_id = htobe64(stream->relayd_stream_id); + hdr.padding_size = htobe32(padding); + ret = lttng_write(fd, (void *) &hdr, sizeof(hdr)); + if (ret < sizeof(hdr)) { + /* + * This error means that the fd's end is closed so ignore the PERROR + * not to clubber the error output since this can happen in a normal + * code path. + */ + if (errno != EPIPE) { + PERROR("write metadata stream id"); + } + DBG3("Consumer failed to write relayd metadata id (errno: %d)", errno); + /* + * Set ret to a negative value because if ret != sizeof(hdr), we don't + * handle writting the missing part so report that as an error and + * don't lie to the caller. + */ + ret = -1; + goto end; + } + DBG("Metadata stream id %" PRIu64 " with padding %lu written before data", + stream->relayd_stream_id, padding); + +end: + return (int) ret; +} + +/* + * Mmap the ring buffer, read it and write the data to the tracefile. This is a + * core function for writing trace buffers to either the local filesystem or + * the network. + * + * It must be called with the stream lock held. + * + * Careful review MUST be put if any changes occur! * * Returns the number of bytes written */ -int lttng_consumer_on_read_subbuffer_mmap( +ssize_t lttng_consumer_on_read_subbuffer_mmap( struct lttng_consumer_local_data *ctx, - struct lttng_consumer_stream *stream, unsigned long len) + struct lttng_consumer_stream *stream, unsigned long len, + unsigned long padding, + struct ctf_packet_index *index) { + unsigned long mmap_offset; + void *mmap_base; + ssize_t ret = 0; + off_t orig_offset = stream->out_fd_offset; + /* Default is on the disk */ + int outfd = stream->out_fd; + struct consumer_relayd_sock_pair *relayd = NULL; + unsigned int relayd_hang_up = 0; + + /* RCU lock for the relayd pointer */ + rcu_read_lock(); + + /* Flag that the current stream if set for network streaming. */ + if (stream->net_seq_idx != (uint64_t) -1ULL) { + relayd = consumer_find_relayd(stream->net_seq_idx); + if (relayd == NULL) { + ret = -EPIPE; + goto end; + } + } + + /* get the offset inside the fd to mmap */ switch (consumer_data.type) { case LTTNG_CONSUMER_KERNEL: - return lttng_kconsumer_on_read_subbuffer_mmap(ctx, stream, len); + mmap_base = stream->mmap_base; + ret = kernctl_get_mmap_read_offset(stream->wait_fd, &mmap_offset); + if (ret < 0) { + ret = -errno; + PERROR("tracer ctl get_mmap_read_offset"); + goto end; + } + break; case LTTNG_CONSUMER32_UST: case LTTNG_CONSUMER64_UST: - return lttng_ustconsumer_on_read_subbuffer_mmap(ctx, stream, len); + mmap_base = lttng_ustctl_get_mmap_base(stream); + if (!mmap_base) { + ERR("read mmap get mmap base for stream %s", stream->name); + ret = -EPERM; + goto end; + } + ret = lttng_ustctl_get_mmap_read_offset(stream, &mmap_offset); + if (ret != 0) { + PERROR("tracer ctl get_mmap_read_offset"); + ret = -EINVAL; + goto end; + } + break; default: ERR("Unknown consumer_data type"); assert(0); } - return 0; + /* Handle stream on the relayd if the output is on the network */ + if (relayd) { + unsigned long netlen = len; + + /* + * Lock the control socket for the complete duration of the function + * since from this point on we will use the socket. + */ + if (stream->metadata_flag) { + /* Metadata requires the control socket. */ + pthread_mutex_lock(&relayd->ctrl_sock_mutex); + netlen += sizeof(struct lttcomm_relayd_metadata_payload); + } + + ret = write_relayd_stream_header(stream, netlen, padding, relayd); + if (ret < 0) { + relayd_hang_up = 1; + goto write_error; + } + /* Use the returned socket. */ + outfd = ret; + + /* Write metadata stream id before payload */ + if (stream->metadata_flag) { + ret = write_relayd_metadata_id(outfd, stream, relayd, padding); + if (ret < 0) { + relayd_hang_up = 1; + goto write_error; + } + } + } else { + /* No streaming, we have to set the len with the full padding */ + len += padding; + + /* + * Check if we need to change the tracefile before writing the packet. + */ + if (stream->chan->tracefile_size > 0 && + (stream->tracefile_size_current + len) > + stream->chan->tracefile_size) { + ret = utils_rotate_stream_file(stream->chan->pathname, + stream->name, stream->chan->tracefile_size, + stream->chan->tracefile_count, stream->uid, stream->gid, + stream->out_fd, &(stream->tracefile_count_current), + &stream->out_fd); + if (ret < 0) { + ERR("Rotating output file"); + goto end; + } + outfd = stream->out_fd; + + if (stream->index_fd >= 0) { + ret = index_create_file(stream->chan->pathname, + stream->name, stream->uid, stream->gid, + stream->chan->tracefile_size, + stream->tracefile_count_current); + if (ret < 0) { + goto end; + } + stream->index_fd = ret; + } + + /* Reset current size because we just perform a rotation. */ + stream->tracefile_size_current = 0; + stream->out_fd_offset = 0; + orig_offset = 0; + } + stream->tracefile_size_current += len; + if (index) { + index->offset = htobe64(stream->out_fd_offset); + } + } + + /* + * This call guarantee that len or less is returned. It's impossible to + * receive a ret value that is bigger than len. + */ + ret = lttng_write(outfd, mmap_base + mmap_offset, len); + DBG("Consumer mmap write() ret %zd (len %lu)", ret, len); + if (ret < 0 || ((size_t) ret != len)) { + /* + * Report error to caller if nothing was written else at least send the + * amount written. + */ + if (ret < 0) { + ret = -errno; + } + relayd_hang_up = 1; + + /* Socket operation failed. We consider the relayd dead */ + if (errno == EPIPE || errno == EINVAL || errno == EBADF) { + /* + * This is possible if the fd is closed on the other side + * (outfd) or any write problem. It can be verbose a bit for a + * normal execution if for instance the relayd is stopped + * abruptly. This can happen so set this to a DBG statement. + */ + DBG("Consumer mmap write detected relayd hang up"); + } else { + /* Unhandled error, print it and stop function right now. */ + PERROR("Error in write mmap (ret %zd != len %lu)", ret, len); + } + goto write_error; + } + stream->output_written += ret; + + /* This call is useless on a socket so better save a syscall. */ + if (!relayd) { + /* This won't block, but will start writeout asynchronously */ + lttng_sync_file_range(outfd, stream->out_fd_offset, len, + SYNC_FILE_RANGE_WRITE); + stream->out_fd_offset += len; + } + lttng_consumer_sync_trace_file(stream, orig_offset); + +write_error: + /* + * This is a special case that the relayd has closed its socket. Let's + * cleanup the relayd object and all associated streams. + */ + if (relayd && relayd_hang_up) { + cleanup_relayd(relayd, ctx); + } + +end: + /* Unlock only if ctrl socket used */ + if (relayd && stream->metadata_flag) { + pthread_mutex_unlock(&relayd->ctrl_sock_mutex); + } + + rcu_read_unlock(); + return ret; } /* * Splice the data from the ring buffer to the tracefile. * + * It must be called with the stream lock held. + * * Returns the number of bytes spliced. */ -int lttng_consumer_on_read_subbuffer_splice( +ssize_t lttng_consumer_on_read_subbuffer_splice( struct lttng_consumer_local_data *ctx, - struct lttng_consumer_stream *stream, unsigned long len) + struct lttng_consumer_stream *stream, unsigned long len, + unsigned long padding, + struct ctf_packet_index *index) { + ssize_t ret = 0, written = 0, ret_splice = 0; + loff_t offset = 0; + off_t orig_offset = stream->out_fd_offset; + int fd = stream->wait_fd; + /* Default is on the disk */ + int outfd = stream->out_fd; + struct consumer_relayd_sock_pair *relayd = NULL; + int *splice_pipe; + unsigned int relayd_hang_up = 0; + switch (consumer_data.type) { case LTTNG_CONSUMER_KERNEL: - return lttng_kconsumer_on_read_subbuffer_splice(ctx, stream, len); + break; case LTTNG_CONSUMER32_UST: case LTTNG_CONSUMER64_UST: + /* Not supported for user space tracing */ return -ENOSYS; default: ERR("Unknown consumer_data type"); assert(0); - return -ENOSYS; } + /* RCU lock for the relayd pointer */ + rcu_read_lock(); + + /* Flag that the current stream if set for network streaming. */ + if (stream->net_seq_idx != (uint64_t) -1ULL) { + relayd = consumer_find_relayd(stream->net_seq_idx); + if (relayd == NULL) { + written = -ret; + goto end; + } + } + splice_pipe = stream->splice_pipe; + + /* Write metadata stream id before payload */ + if (relayd) { + unsigned long total_len = len; + + if (stream->metadata_flag) { + /* + * Lock the control socket for the complete duration of the function + * since from this point on we will use the socket. + */ + pthread_mutex_lock(&relayd->ctrl_sock_mutex); + + ret = write_relayd_metadata_id(splice_pipe[1], stream, relayd, + padding); + if (ret < 0) { + written = ret; + relayd_hang_up = 1; + goto write_error; + } + + total_len += sizeof(struct lttcomm_relayd_metadata_payload); + } + + ret = write_relayd_stream_header(stream, total_len, padding, relayd); + if (ret < 0) { + written = ret; + relayd_hang_up = 1; + goto write_error; + } + /* Use the returned socket. */ + outfd = ret; + } else { + /* No streaming, we have to set the len with the full padding */ + len += padding; + + /* + * Check if we need to change the tracefile before writing the packet. + */ + if (stream->chan->tracefile_size > 0 && + (stream->tracefile_size_current + len) > + stream->chan->tracefile_size) { + ret = utils_rotate_stream_file(stream->chan->pathname, + stream->name, stream->chan->tracefile_size, + stream->chan->tracefile_count, stream->uid, stream->gid, + stream->out_fd, &(stream->tracefile_count_current), + &stream->out_fd); + if (ret < 0) { + written = ret; + ERR("Rotating output file"); + goto end; + } + outfd = stream->out_fd; + + if (stream->index_fd >= 0) { + ret = index_create_file(stream->chan->pathname, + stream->name, stream->uid, stream->gid, + stream->chan->tracefile_size, + stream->tracefile_count_current); + if (ret < 0) { + written = ret; + goto end; + } + stream->index_fd = ret; + } + + /* Reset current size because we just perform a rotation. */ + stream->tracefile_size_current = 0; + stream->out_fd_offset = 0; + orig_offset = 0; + } + stream->tracefile_size_current += len; + index->offset = htobe64(stream->out_fd_offset); + } + + while (len > 0) { + DBG("splice chan to pipe offset %lu of len %lu (fd : %d, pipe: %d)", + (unsigned long)offset, len, fd, splice_pipe[1]); + ret_splice = splice(fd, &offset, splice_pipe[1], NULL, len, + SPLICE_F_MOVE | SPLICE_F_MORE); + DBG("splice chan to pipe, ret %zd", ret_splice); + if (ret_splice < 0) { + ret = errno; + written = -ret; + PERROR("Error in relay splice"); + goto splice_error; + } + + /* Handle stream on the relayd if the output is on the network */ + if (relayd && stream->metadata_flag) { + size_t metadata_payload_size = + sizeof(struct lttcomm_relayd_metadata_payload); + + /* Update counter to fit the spliced data */ + ret_splice += metadata_payload_size; + len += metadata_payload_size; + /* + * We do this so the return value can match the len passed as + * argument to this function. + */ + written -= metadata_payload_size; + } + + /* Splice data out */ + ret_splice = splice(splice_pipe[0], NULL, outfd, NULL, + ret_splice, SPLICE_F_MOVE | SPLICE_F_MORE); + DBG("Consumer splice pipe to file (out_fd: %d), ret %zd", + outfd, ret_splice); + if (ret_splice < 0) { + ret = errno; + written = -ret; + relayd_hang_up = 1; + goto write_error; + } else if (ret_splice > len) { + /* + * We don't expect this code path to be executed but you never know + * so this is an extra protection agains a buggy splice(). + */ + ret = errno; + written += ret_splice; + PERROR("Wrote more data than requested %zd (len: %lu)", ret_splice, + len); + goto splice_error; + } else { + /* All good, update current len and continue. */ + len -= ret_splice; + } + + /* This call is useless on a socket so better save a syscall. */ + if (!relayd) { + /* This won't block, but will start writeout asynchronously */ + lttng_sync_file_range(outfd, stream->out_fd_offset, ret_splice, + SYNC_FILE_RANGE_WRITE); + stream->out_fd_offset += ret_splice; + } + stream->output_written += ret_splice; + written += ret_splice; + } + lttng_consumer_sync_trace_file(stream, orig_offset); + goto end; + +write_error: + /* + * This is a special case that the relayd has closed its socket. Let's + * cleanup the relayd object and all associated streams. + */ + if (relayd && relayd_hang_up) { + cleanup_relayd(relayd, ctx); + /* Skip splice error so the consumer does not fail */ + goto end; + } + +splice_error: + /* send the appropriate error description to sessiond */ + switch (ret) { + case EINVAL: + lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_SPLICE_EINVAL); + break; + case ENOMEM: + lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_SPLICE_ENOMEM); + break; + case ESPIPE: + lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_SPLICE_ESPIPE); + break; + } + +end: + if (relayd && stream->metadata_flag) { + pthread_mutex_unlock(&relayd->ctrl_sock_mutex); + } + + rcu_read_unlock(); + return written; } /* @@ -773,21 +1882,19 @@ int lttng_consumer_on_read_subbuffer_splice( * * Returns 0 on success, < 0 on error */ -int lttng_consumer_take_snapshot(struct lttng_consumer_local_data *ctx, - struct lttng_consumer_stream *stream) +int lttng_consumer_take_snapshot(struct lttng_consumer_stream *stream) { switch (consumer_data.type) { case LTTNG_CONSUMER_KERNEL: - return lttng_kconsumer_take_snapshot(ctx, stream); + return lttng_kconsumer_take_snapshot(stream); case LTTNG_CONSUMER32_UST: case LTTNG_CONSUMER64_UST: - return lttng_ustconsumer_take_snapshot(ctx, stream); + return lttng_ustconsumer_take_snapshot(stream); default: ERR("Unknown consumer_data type"); assert(0); return -ENOSYS; } - } /* @@ -795,17 +1902,15 @@ int lttng_consumer_take_snapshot(struct lttng_consumer_local_data *ctx, * * Returns 0 on success, < 0 on error */ -int lttng_consumer_get_produced_snapshot( - struct lttng_consumer_local_data *ctx, - struct lttng_consumer_stream *stream, +int lttng_consumer_get_produced_snapshot(struct lttng_consumer_stream *stream, unsigned long *pos) { switch (consumer_data.type) { case LTTNG_CONSUMER_KERNEL: - return lttng_kconsumer_get_produced_snapshot(ctx, stream, pos); + return lttng_kconsumer_get_produced_snapshot(stream, pos); case LTTNG_CONSUMER32_UST: case LTTNG_CONSUMER64_UST: - return lttng_ustconsumer_get_produced_snapshot(ctx, stream, pos); + return lttng_ustconsumer_get_produced_snapshot(stream, pos); default: ERR("Unknown consumer_data type"); assert(0); @@ -829,195 +1934,1048 @@ int lttng_consumer_recv_cmd(struct lttng_consumer_local_data *ctx, } } +void lttng_consumer_close_all_metadata(void) +{ + switch (consumer_data.type) { + case LTTNG_CONSUMER_KERNEL: + /* + * The Kernel consumer has a different metadata scheme so we don't + * close anything because the stream will be closed by the session + * daemon. + */ + break; + case LTTNG_CONSUMER32_UST: + case LTTNG_CONSUMER64_UST: + /* + * Close all metadata streams. The metadata hash table is passed and + * this call iterates over it by closing all wakeup fd. This is safe + * because at this point we are sure that the metadata producer is + * either dead or blocked. + */ + lttng_ustconsumer_close_all_metadata(metadata_ht); + break; + default: + ERR("Unknown consumer_data type"); + assert(0); + } +} + /* - * This thread polls the fds in the set to consume the data and write - * it to tracefile if necessary. + * Clean up a metadata stream and free its memory. */ -void *lttng_consumer_thread_poll_fds(void *data) +void consumer_del_metadata_stream(struct lttng_consumer_stream *stream, + struct lttng_ht *ht) { - int num_rdy, num_hup, high_prio, ret, i; - struct pollfd *pollfd = NULL; - /* local view of the streams */ - struct lttng_consumer_stream **local_stream = NULL; - /* local view of consumer_data.fds_count */ - int nb_fd = 0; - char tmp; - int tmp2; - struct lttng_consumer_local_data *ctx = data; + struct lttng_consumer_channel *free_chan = NULL; - rcu_register_thread(); + 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); - local_stream = zmalloc(sizeof(struct lttng_consumer_stream)); + DBG3("Consumer delete metadata stream %d", stream->wait_fd); - while (1) { - high_prio = 0; - num_hup = 0; + pthread_mutex_lock(&consumer_data.lock); + pthread_mutex_lock(&stream->chan->lock); + pthread_mutex_lock(&stream->lock); - /* - * 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) { - if (pollfd != NULL) { - free(pollfd); - pollfd = NULL; - } - if (local_stream != NULL) { - free(local_stream); - local_stream = NULL; - } + /* Remove any reference to that stream. */ + consumer_stream_delete(stream, ht); - /* allocate for all fds + 1 for the consumer_poll_pipe */ - pollfd = zmalloc((consumer_data.stream_count + 1) * sizeof(struct pollfd)); - if (pollfd == NULL) { - perror("pollfd malloc"); - pthread_mutex_unlock(&consumer_data.lock); - goto end; - } + /* Close down everything including the relayd if one. */ + consumer_stream_close(stream); + /* Destroy tracer buffers of the stream. */ + consumer_stream_destroy_buffers(stream); - /* allocate for all fds + 1 for the consumer_poll_pipe */ - local_stream = zmalloc((consumer_data.stream_count + 1) * - sizeof(struct lttng_consumer_stream)); - if (local_stream == NULL) { - perror("local_stream malloc"); - pthread_mutex_unlock(&consumer_data.lock); - goto end; - } - ret = consumer_update_poll_array(ctx, &pollfd, local_stream); - if (ret < 0) { - ERR("Error in allocating pollfd or local_outfds"); - lttng_consumer_send_error(ctx, CONSUMERD_POLL_ERROR); - pthread_mutex_unlock(&consumer_data.lock); - goto end; - } - nb_fd = ret; - consumer_data.need_update = 0; - } - pthread_mutex_unlock(&consumer_data.lock); + /* Atomically decrement channel refcount since other threads can use it. */ + if (!uatomic_sub_return(&stream->chan->refcount, 1) + && !uatomic_read(&stream->chan->nb_init_stream_left)) { + /* Go for channel deletion! */ + free_chan = stream->chan; + } - /* poll on the array of fds */ - DBG("polling on %d fd", nb_fd + 1); - num_rdy = poll(pollfd, nb_fd + 1, consumer_poll_timeout); - DBG("poll num_rdy : %d", num_rdy); - if (num_rdy == -1) { - perror("Poll error"); - lttng_consumer_send_error(ctx, CONSUMERD_POLL_ERROR); - goto end; - } else if (num_rdy == 0) { - DBG("Polling thread timed out"); + /* + * Nullify the stream reference so it is not used after deletion. The + * channel lock MUST be acquired before being able to check for a NULL + * pointer value. + */ + stream->chan->metadata_stream = NULL; + + pthread_mutex_unlock(&stream->lock); + pthread_mutex_unlock(&stream->chan->lock); + pthread_mutex_unlock(&consumer_data.lock); + + if (free_chan) { + consumer_del_channel(free_chan); + } + + consumer_stream_free(stream); +} + +/* + * Action done with the metadata stream when adding it to the consumer internal + * data structures to handle it. + */ +int consumer_add_metadata_stream(struct lttng_consumer_stream *stream) +{ + struct lttng_ht *ht = metadata_ht; + int ret = 0; + struct lttng_ht_iter iter; + struct lttng_ht_node_u64 *node; + + assert(stream); + assert(ht); + + DBG3("Adding metadata stream %" PRIu64 " to hash table", stream->key); + + pthread_mutex_lock(&consumer_data.lock); + pthread_mutex_lock(&stream->chan->lock); + pthread_mutex_lock(&stream->chan->timer_lock); + pthread_mutex_lock(&stream->lock); + + /* + * From here, refcounts are updated so be _careful_ when returning an error + * after this point. + */ + + rcu_read_lock(); + + /* + * Lookup the stream just to make sure it does not exist in our internal + * state. This should NEVER happen. + */ + lttng_ht_lookup(ht, &stream->key, &iter); + node = lttng_ht_iter_get_node_u64(&iter); + assert(!node); + + /* + * When nb_init_stream_left reaches 0, we don't need to trigger any action + * in terms of destroying the associated channel, because the action that + * causes the count to become 0 also causes a stream to be added. The + * channel deletion will thus be triggered by the following removal of this + * stream. + */ + if (uatomic_read(&stream->chan->nb_init_stream_left) > 0) { + /* Increment refcount before decrementing nb_init_stream_left */ + cmm_smp_wmb(); + uatomic_dec(&stream->chan->nb_init_stream_left); + } + + lttng_ht_add_unique_u64(ht, &stream->node); + + lttng_ht_add_unique_u64(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); + + 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); + return ret; +} + +/* + * Delete data stream that are flagged for deletion (endpoint_status). + */ +static void validate_endpoint_status_data_stream(void) +{ + struct lttng_ht_iter iter; + struct lttng_consumer_stream *stream; + + DBG("Consumer delete flagged data stream"); + + rcu_read_lock(); + cds_lfht_for_each_entry(data_ht->ht, &iter.iter, stream, node.node) { + /* Validate delete flag of the stream */ + if (stream->endpoint_status == CONSUMER_ENDPOINT_ACTIVE) { + continue; + } + /* Delete it right now */ + consumer_del_stream(stream, data_ht); + } + rcu_read_unlock(); +} + +/* + * Delete metadata stream that are flagged for deletion (endpoint_status). + */ +static void validate_endpoint_status_metadata_stream( + struct lttng_poll_event *pollset) +{ + struct lttng_ht_iter iter; + struct lttng_consumer_stream *stream; + + DBG("Consumer delete flagged metadata stream"); + + assert(pollset); + + rcu_read_lock(); + cds_lfht_for_each_entry(metadata_ht->ht, &iter.iter, stream, node.node) { + /* Validate delete flag of the stream */ + if (stream->endpoint_status == CONSUMER_ENDPOINT_ACTIVE) { + continue; + } + /* + * Remove from pollset so the metadata thread can continue without + * blocking on a deleted stream. + */ + lttng_poll_del(pollset, stream->wait_fd); + + /* Delete it right now */ + consumer_del_metadata_stream(stream, metadata_ht); + } + rcu_read_unlock(); +} + +/* + * Thread polls on metadata file descriptor and write them on disk or on the + * network. + */ +void *consumer_thread_metadata_poll(void *data) +{ + int ret, i, pollfd, err = -1; + uint32_t revents, nb_fd; + struct lttng_consumer_stream *stream = NULL; + struct lttng_ht_iter iter; + struct lttng_ht_node_u64 *node; + struct lttng_poll_event events; + struct lttng_consumer_local_data *ctx = data; + ssize_t len; + + rcu_register_thread(); + + health_register(health_consumerd, HEALTH_CONSUMERD_TYPE_METADATA); + + if (testpoint(consumerd_thread_metadata)) { + goto error_testpoint; + } + + health_code_update(); + + DBG("Thread metadata poll started"); + + /* Size is set to 1 for the consumer_metadata pipe */ + ret = lttng_poll_create(&events, 2, LTTNG_CLOEXEC); + if (ret < 0) { + ERR("Poll set creation failed"); + goto end_poll; + } + + ret = lttng_poll_add(&events, + lttng_pipe_get_readfd(ctx->consumer_metadata_pipe), LPOLLIN); + if (ret < 0) { + goto end; + } + + /* Main loop */ + DBG("Metadata main loop started"); + + while (1) { +restart: + health_code_update(); + health_poll_entry(); + DBG("Metadata poll wait"); + ret = lttng_poll_wait(&events, -1); + DBG("Metadata poll return from wait with %d fd(s)", + LTTNG_POLL_GETNB(&events)); + health_poll_exit(); + DBG("Metadata event catched in thread"); + if (ret < 0) { + if (errno == EINTR) { + ERR("Poll EINTR catched"); + goto restart; + } + if (LTTNG_POLL_GETNB(&events) == 0) { + err = 0; /* All is OK */ + } goto end; } + nb_fd = ret; + + /* From here, the event is a metadata wait fd */ + for (i = 0; i < nb_fd; i++) { + health_code_update(); + + revents = LTTNG_POLL_GETEV(&events, i); + pollfd = LTTNG_POLL_GETFD(&events, i); + + if (!revents) { + /* No activity for this FD (poll implementation). */ + continue; + } + + if (pollfd == lttng_pipe_get_readfd(ctx->consumer_metadata_pipe)) { + if (revents & (LPOLLERR | LPOLLHUP )) { + DBG("Metadata thread pipe hung up"); + /* + * Remove the pipe from the poll set and continue the loop + * since their might be data to consume. + */ + lttng_poll_del(&events, + lttng_pipe_get_readfd(ctx->consumer_metadata_pipe)); + lttng_pipe_read_close(ctx->consumer_metadata_pipe); + continue; + } else if (revents & LPOLLIN) { + ssize_t pipe_len; + + pipe_len = lttng_pipe_read(ctx->consumer_metadata_pipe, + &stream, sizeof(stream)); + if (pipe_len < sizeof(stream)) { + PERROR("read metadata stream"); + /* + * Continue here to handle the rest of the streams. + */ + continue; + } + + /* A NULL stream means that the state has changed. */ + if (stream == NULL) { + /* Check for deleted streams. */ + validate_endpoint_status_metadata_stream(&events); + goto restart; + } + + DBG("Adding metadata stream %d to poll set", + stream->wait_fd); + + /* Add metadata stream to the global poll events list */ + lttng_poll_add(&events, stream->wait_fd, + LPOLLIN | LPOLLPRI | LPOLLHUP); + } + + /* Handle other stream */ + continue; + } + + rcu_read_lock(); + { + uint64_t tmp_id = (uint64_t) pollfd; + + lttng_ht_lookup(metadata_ht, &tmp_id, &iter); + } + node = lttng_ht_iter_get_node_u64(&iter); + assert(node); + + stream = caa_container_of(node, struct lttng_consumer_stream, + node); + + /* Check for error event */ + 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)) { + DBG("Attempting to flush and consume the UST buffers"); + lttng_ustconsumer_on_stream_hangup(stream); + + /* We just flushed the stream now read it. */ + do { + health_code_update(); + + len = ctx->on_buffer_ready(stream, ctx); + /* + * We don't check the return value here since if we get + * a negative len, it means an error occured thus we + * simply remove it from the poll set and free the + * stream. + */ + } while (len > 0); + } + + lttng_poll_del(&events, stream->wait_fd); + /* + * This call update the channel states, closes file descriptors + * and securely free the stream. + */ + consumer_del_metadata_stream(stream, metadata_ht); + } else 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); + + do { + health_code_update(); + + len = ctx->on_buffer_ready(stream, ctx); + /* + * We don't check the return value here since if we get + * a negative len, it means an error occured thus we + * simply remove it from the poll set and free the + * stream. + */ + } while (len > 0); + + /* It's ok to have an unavailable sub-buffer */ + if (len < 0 && len != -EAGAIN && len != -ENODATA) { + /* Clean up stream from consumer and free it. */ + lttng_poll_del(&events, stream->wait_fd); + consumer_del_metadata_stream(stream, metadata_ht); + } + } + + /* Release RCU lock for the stream looked up */ + rcu_read_unlock(); + } + } + + /* All is OK */ + err = 0; +end: + DBG("Metadata poll thread exiting"); + + lttng_poll_clean(&events); +end_poll: +error_testpoint: + if (err) { + health_error(); + ERR("Health error occurred in %s", __func__); + } + health_unregister(health_consumerd); + rcu_unregister_thread(); + return NULL; +} + +/* + * This thread polls the fds in the set to consume the data and write + * it to tracefile if necessary. + */ +void *consumer_thread_data_poll(void *data) +{ + int num_rdy, num_hup, high_prio, ret, i, err = -1; + struct pollfd *pollfd = NULL; + /* local view of the streams */ + struct lttng_consumer_stream **local_stream = NULL, *new_stream = NULL; + /* local view of consumer_data.fds_count */ + int nb_fd = 0; + struct lttng_consumer_local_data *ctx = data; + ssize_t len; + + rcu_register_thread(); + + health_register(health_consumerd, HEALTH_CONSUMERD_TYPE_DATA); + + if (testpoint(consumerd_thread_data)) { + goto error_testpoint; + } + + health_code_update(); + + local_stream = zmalloc(sizeof(struct lttng_consumer_stream *)); + if (local_stream == NULL) { + PERROR("local_stream malloc"); + goto end; + } + + while (1) { + health_code_update(); + + high_prio = 0; + num_hup = 0; + + /* + * 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) { + free(pollfd); + pollfd = NULL; + + free(local_stream); + local_stream = NULL; + + /* + * Allocate for all fds +1 for the consumer_data_pipe and +1 for + * wake up pipe. + */ + pollfd = zmalloc((consumer_data.stream_count + 2) * sizeof(struct pollfd)); + if (pollfd == NULL) { + PERROR("pollfd malloc"); + pthread_mutex_unlock(&consumer_data.lock); + goto end; + } + + local_stream = zmalloc((consumer_data.stream_count + 2) * + sizeof(struct lttng_consumer_stream *)); + if (local_stream == NULL) { + PERROR("local_stream malloc"); + pthread_mutex_unlock(&consumer_data.lock); + goto end; + } + ret = update_poll_array(ctx, &pollfd, local_stream, + data_ht); + 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); + goto end; + } + nb_fd = ret; + consumer_data.need_update = 0; + } + pthread_mutex_unlock(&consumer_data.lock); + /* No FDs and consumer_quit, consumer_cleanup the thread */ if (nb_fd == 0 && consumer_quit == 1) { + err = 0; /* All is OK */ + goto end; + } + /* poll on the array of fds */ + restart: + DBG("polling on %d fd", nb_fd + 2); + health_poll_entry(); + num_rdy = poll(pollfd, nb_fd + 2, -1); + health_poll_exit(); + DBG("poll num_rdy : %d", num_rdy); + if (num_rdy == -1) { + /* + * Restart interrupted system call. + */ + if (errno == EINTR) { + goto restart; + } + PERROR("Poll error"); + lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_POLL_ERROR); + goto end; + } else if (num_rdy == 0) { + DBG("Polling thread timed out"); goto end; } /* - * If the consumer_poll_pipe triggered poll go - * directly to the beginning of the loop to update the - * array. We want to prioritize array update over - * low-priority reads. + * If the consumer_data_pipe triggered poll go directly to the + * beginning of the loop to update the array. We want to prioritize + * array update over low-priority reads. */ - if (pollfd[nb_fd].revents & POLLIN) { - DBG("consumer_poll_pipe wake up"); - tmp2 = read(ctx->consumer_poll_pipe[0], &tmp, 1); - if (tmp2 < 0) { - perror("read consumer poll"); + if (pollfd[nb_fd].revents & (POLLIN | POLLPRI)) { + ssize_t pipe_readlen; + + DBG("consumer_data_pipe wake up"); + pipe_readlen = lttng_pipe_read(ctx->consumer_data_pipe, + &new_stream, sizeof(new_stream)); + if (pipe_readlen < sizeof(new_stream)) { + PERROR("Consumer data pipe"); + /* Continue so we can at least handle the current stream(s). */ + continue; + } + + /* + * If the stream is NULL, just ignore it. It's also possible that + * the sessiond poll thread changed the consumer_quit state and is + * waking us up to test it. + */ + if (new_stream == NULL) { + validate_endpoint_status_data_stream(); + continue; } + + /* Continue to update the local streams and handle prio ones */ continue; } + /* Handle wakeup pipe. */ + if (pollfd[nb_fd + 1].revents & (POLLIN | POLLPRI)) { + char dummy; + ssize_t pipe_readlen; + + pipe_readlen = lttng_pipe_read(ctx->consumer_wakeup_pipe, &dummy, + sizeof(dummy)); + if (pipe_readlen < 0) { + PERROR("Consumer data wakeup pipe"); + } + /* We've been awakened to handle stream(s). */ + ctx->has_wakeup = 0; + } + /* Take care of high priority channels first. */ for (i = 0; i < nb_fd; i++) { + health_code_update(); + + if (local_stream[i] == NULL) { + continue; + } if (pollfd[i].revents & POLLPRI) { DBG("Urgent read on fd %d", pollfd[i].fd); high_prio = 1; - ret = ctx->on_buffer_ready(local_stream[i], ctx); + len = ctx->on_buffer_ready(local_stream[i], ctx); /* it's ok to have an unavailable sub-buffer */ - if (ret == EAGAIN) { - ret = 0; + if (len < 0 && len != -EAGAIN && len != -ENODATA) { + /* Clean the stream and free it. */ + consumer_del_stream(local_stream[i], data_ht); + local_stream[i] = NULL; + } else if (len > 0) { + local_stream[i]->data_read = 1; + } + } + } + + /* + * If we read high prio channel in this loop, try again + * for more high prio data. + */ + if (high_prio) { + continue; + } + + /* Take care of low priority channels. */ + for (i = 0; i < nb_fd; i++) { + health_code_update(); + + if (local_stream[i] == NULL) { + continue; + } + if ((pollfd[i].revents & POLLIN) || + local_stream[i]->hangup_flush_done || + local_stream[i]->has_data) { + DBG("Normal read on fd %d", pollfd[i].fd); + len = ctx->on_buffer_ready(local_stream[i], ctx); + /* it's ok to have an unavailable sub-buffer */ + if (len < 0 && len != -EAGAIN && len != -ENODATA) { + /* Clean the stream and free it. */ + consumer_del_stream(local_stream[i], data_ht); + local_stream[i] = NULL; + } else if (len > 0) { + local_stream[i]->data_read = 1; + } + } + } + + /* Handle hangup and errors */ + for (i = 0; i < nb_fd; i++) { + health_code_update(); + + if (local_stream[i] == NULL) { + continue; + } + 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)) { + DBG("fd %d is hup|err|nval. Attempting flush and read.", + pollfd[i].fd); + lttng_ustconsumer_on_stream_hangup(local_stream[i]); + /* Attempt read again, for the data we just flushed. */ + local_stream[i]->data_read = 1; + } + /* + * If the poll flag is HUP/ERR/NVAL and we have + * read no data in this pass, we can remove the + * stream from its hash table. + */ + if ((pollfd[i].revents & POLLHUP)) { + DBG("Polling fd %d tells it has hung up.", pollfd[i].fd); + if (!local_stream[i]->data_read) { + consumer_del_stream(local_stream[i], data_ht); + local_stream[i] = NULL; + num_hup++; } } else if (pollfd[i].revents & POLLERR) { ERR("Error returned in polling fd %d.", pollfd[i].fd); - rcu_read_lock(); - consumer_del_stream_rcu(&local_stream[i]->node.head); - rcu_read_unlock(); - num_hup++; + if (!local_stream[i]->data_read) { + consumer_del_stream(local_stream[i], data_ht); + local_stream[i] = NULL; + num_hup++; + } } else if (pollfd[i].revents & POLLNVAL) { ERR("Polling fd %d tells fd is not open.", pollfd[i].fd); - rcu_read_lock(); - consumer_del_stream_rcu(&local_stream[i]->node.head); - rcu_read_unlock(); - num_hup++; - } else if ((pollfd[i].revents & POLLHUP) && - !(pollfd[i].revents & POLLIN)) { - if (consumer_data.type == LTTNG_CONSUMER32_UST - || consumer_data.type == LTTNG_CONSUMER64_UST) { - DBG("Polling fd %d tells it has hung up. Attempting flush and read.", - pollfd[i].fd); - if (!local_stream[i]->hangup_flush_done) { - lttng_ustconsumer_on_stream_hangup(local_stream[i]); - /* read after flush */ - do { - ret = ctx->on_buffer_ready(local_stream[i], ctx); - } while (ret == EAGAIN); - } - } else { - DBG("Polling fd %d tells it has hung up.", pollfd[i].fd); + if (!local_stream[i]->data_read) { + consumer_del_stream(local_stream[i], data_ht); + local_stream[i] = NULL; + num_hup++; } - rcu_read_lock(); - consumer_del_stream_rcu(&local_stream[i]->node.head); - rcu_read_unlock(); - num_hup++; + } + if (local_stream[i] != NULL) { + local_stream[i]->data_read = 0; } } + } + /* All is OK */ + err = 0; +end: + DBG("polling thread exiting"); + free(pollfd); + free(local_stream); - /* If every buffer FD has hung up, we end the read loop here */ - if (nb_fd > 0 && num_hup == nb_fd) { - DBG("every buffer FD has hung up\n"); - if (consumer_quit == 1) { - goto end; + /* + * Close the write side of the pipe so epoll_wait() in + * consumer_thread_metadata_poll can catch it. The thread is monitoring the + * read side of the pipe. If we close them both, epoll_wait strangely does + * not return and could create a endless wait period if the pipe is the + * only tracked fd in the poll set. The thread will take care of closing + * the read side. + */ + (void) lttng_pipe_write_close(ctx->consumer_metadata_pipe); + +error_testpoint: + if (err) { + health_error(); + ERR("Health error occurred in %s", __func__); + } + health_unregister(health_consumerd); + + rcu_unregister_thread(); + return NULL; +} + +/* + * Close wake-up end of each stream belonging to the channel. This will + * allow the poll() on the stream read-side to detect when the + * write-side (application) finally closes them. + */ +static +void consumer_close_channel_streams(struct lttng_consumer_channel *channel) +{ + struct lttng_ht *ht; + struct lttng_consumer_stream *stream; + struct lttng_ht_iter iter; + + 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; + } + switch (consumer_data.type) { + case LTTNG_CONSUMER_KERNEL: + break; + case LTTNG_CONSUMER32_UST: + case LTTNG_CONSUMER64_UST: + if (stream->metadata_flag) { + /* Safe and protected by the stream lock. */ + lttng_ustconsumer_close_metadata(stream->chan); + } else { + /* + * Note: a mutex is taken internally within + * liblttng-ust-ctl to protect timer wakeup_fd + * use from concurrent close. + */ + lttng_ustconsumer_close_stream_wakeup(stream); } - continue; + break; + default: + ERR("Unknown consumer_data type"); + assert(0); } + next: + pthread_mutex_unlock(&stream->lock); + } + rcu_read_unlock(); +} - /* Take care of low priority channels. */ - if (high_prio == 0) { - for (i = 0; i < nb_fd; i++) { - if (pollfd[i].revents & POLLIN) { - DBG("Normal read on fd %d", pollfd[i].fd); - ret = ctx->on_buffer_ready(local_stream[i], ctx); - /* it's ok to have an unavailable subbuffer */ - if (ret == EAGAIN) { - ret = 0; +static void destroy_channel_ht(struct lttng_ht *ht) +{ + struct lttng_ht_iter iter; + struct lttng_consumer_channel *channel; + int ret; + + if (ht == NULL) { + return; + } + + 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); + } + rcu_read_unlock(); + + lttng_ht_destroy(ht); +} + +/* + * This thread polls the channel fds to detect when they are being + * closed. It closes all related streams if the channel is detected as + * closed. It is currently only used as a shim layer for UST because the + * consumerd needs to keep the per-stream wakeup end of pipes open for + * periodical flush. + */ +void *consumer_thread_channel_poll(void *data) +{ + int ret, i, pollfd, err = -1; + uint32_t revents, nb_fd; + struct lttng_consumer_channel *chan = NULL; + struct lttng_ht_iter iter; + struct lttng_ht_node_u64 *node; + struct lttng_poll_event events; + struct lttng_consumer_local_data *ctx = data; + struct lttng_ht *channel_ht; + + rcu_register_thread(); + + health_register(health_consumerd, HEALTH_CONSUMERD_TYPE_CHANNEL); + + if (testpoint(consumerd_thread_channel)) { + goto error_testpoint; + } + + health_code_update(); + + channel_ht = lttng_ht_new(0, LTTNG_HT_TYPE_U64); + if (!channel_ht) { + /* ENOMEM at this point. Better to bail out. */ + goto end_ht; + } + + DBG("Thread channel poll started"); + + /* Size is set to 1 for the consumer_channel pipe */ + ret = lttng_poll_create(&events, 2, LTTNG_CLOEXEC); + if (ret < 0) { + ERR("Poll set creation failed"); + goto end_poll; + } + + ret = lttng_poll_add(&events, ctx->consumer_channel_pipe[0], LPOLLIN); + if (ret < 0) { + goto end; + } + + /* Main loop */ + DBG("Channel main loop started"); + + while (1) { +restart: + health_code_update(); + DBG("Channel poll wait"); + health_poll_entry(); + ret = lttng_poll_wait(&events, -1); + DBG("Channel poll return from wait with %d fd(s)", + LTTNG_POLL_GETNB(&events)); + health_poll_exit(); + DBG("Channel event catched in thread"); + if (ret < 0) { + if (errno == EINTR) { + ERR("Poll EINTR catched"); + goto restart; + } + if (LTTNG_POLL_GETNB(&events) == 0) { + err = 0; /* All is OK */ + } + goto end; + } + + nb_fd = ret; + + /* From here, the event is a channel wait fd */ + for (i = 0; i < nb_fd; i++) { + health_code_update(); + + revents = LTTNG_POLL_GETEV(&events, i); + pollfd = LTTNG_POLL_GETFD(&events, i); + + if (!revents) { + /* No activity for this FD (poll implementation). */ + continue; + } + + if (pollfd == ctx->consumer_channel_pipe[0]) { + if (revents & (LPOLLERR | LPOLLHUP)) { + DBG("Channel thread pipe hung up"); + /* + * Remove the pipe from the poll set and continue the loop + * since their might be data to consume. + */ + lttng_poll_del(&events, ctx->consumer_channel_pipe[0]); + continue; + } else if (revents & LPOLLIN) { + enum consumer_channel_action action; + uint64_t key; + + ret = read_channel_pipe(ctx, &chan, &key, &action); + if (ret <= 0) { + ERR("Error reading channel pipe"); + continue; + } + + switch (action) { + case CONSUMER_CHANNEL_ADD: + DBG("Adding channel %d to poll set", + chan->wait_fd); + + lttng_ht_node_init_u64(&chan->wait_fd_node, + chan->wait_fd); + rcu_read_lock(); + lttng_ht_add_unique_u64(channel_ht, + &chan->wait_fd_node); + rcu_read_unlock(); + /* Add channel to the global poll events list */ + lttng_poll_add(&events, chan->wait_fd, + LPOLLIN | LPOLLPRI); + break; + case CONSUMER_CHANNEL_DEL: + { + /* + * This command should never be called if the channel + * has streams monitored by either the data or metadata + * thread. The consumer only notify this thread with a + * channel del. command if it receives a destroy + * channel command from the session daemon that send it + * if a command prior to the GET_CHANNEL failed. + */ + + rcu_read_lock(); + chan = consumer_find_channel(key); + if (!chan) { + rcu_read_unlock(); + ERR("UST consumer get channel key %" PRIu64 " not found for del channel", key); + break; + } + 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); + + switch (consumer_data.type) { + case LTTNG_CONSUMER_KERNEL: + break; + case LTTNG_CONSUMER32_UST: + case LTTNG_CONSUMER64_UST: + health_code_update(); + /* Destroy streams that might have been left in the stream list. */ + clean_channel_stream_list(chan); + break; + default: + ERR("Unknown consumer_data type"); + assert(0); + } + + /* + * Release our own refcount. Force channel deletion even if + * streams were not initialized. + */ + if (!uatomic_sub_return(&chan->refcount, 1)) { + consumer_del_channel(chan); + } + rcu_read_unlock(); + goto restart; } + case CONSUMER_CHANNEL_QUIT: + /* + * Remove the pipe from the poll set and continue the loop + * since their might be data to consume. + */ + lttng_poll_del(&events, ctx->consumer_channel_pipe[0]); + continue; + default: + ERR("Unknown action"); + break; + } + } + + /* Handle other stream */ + continue; + } + + rcu_read_lock(); + { + uint64_t tmp_id = (uint64_t) pollfd; + + lttng_ht_lookup(channel_ht, &tmp_id, &iter); + } + node = lttng_ht_iter_get_node_u64(&iter); + assert(node); + + chan = caa_container_of(node, struct lttng_consumer_channel, + wait_fd_node); + + /* Check for error event */ + if (revents & (LPOLLERR | LPOLLHUP)) { + DBG("Channel fd %d is hup|err.", pollfd); + + lttng_poll_del(&events, chan->wait_fd); + ret = lttng_ht_del(channel_ht, &iter); + assert(ret == 0); + + /* + * This will close the wait fd for each stream associated to + * this channel AND monitored by the data/metadata thread thus + * will be clean by the right thread. + */ + consumer_close_channel_streams(chan); + + /* Release our own refcount */ + if (!uatomic_sub_return(&chan->refcount, 1) + && !uatomic_read(&chan->nb_init_stream_left)) { + consumer_del_channel(chan); } } + + /* Release RCU lock for the channel looked up */ + rcu_read_unlock(); } } + + /* All is OK */ + err = 0; end: - DBG("polling thread exiting"); - if (pollfd != NULL) { - free(pollfd); - pollfd = NULL; + lttng_poll_clean(&events); +end_poll: + destroy_channel_ht(channel_ht); +end_ht: +error_testpoint: + DBG("Channel poll thread exiting"); + if (err) { + health_error(); + ERR("Health error occurred in %s", __func__); + } + health_unregister(health_consumerd); + rcu_unregister_thread(); + return NULL; +} + +static int set_metadata_socket(struct lttng_consumer_local_data *ctx, + struct pollfd *sockpoll, int client_socket) +{ + int ret; + + assert(ctx); + assert(sockpoll); + + ret = lttng_consumer_poll_socket(sockpoll); + if (ret) { + goto error; } - if (local_stream != NULL) { - free(local_stream); - local_stream = NULL; + DBG("Metadata connection on client_socket"); + + /* Blocking call, waiting for transmission */ + ctx->consumer_metadata_socket = lttcomm_accept_unix_sock(client_socket); + if (ctx->consumer_metadata_socket < 0) { + WARN("On accept metadata"); + ret = -1; + goto error; } - rcu_unregister_thread(); - return NULL; + ret = 0; + +error: + return ret; } /* * This thread listens on the consumerd socket and receives the file * descriptors from the session daemon. */ -void *lttng_consumer_thread_receive_fds(void *data) +void *consumer_thread_sessiond_poll(void *data) { - int sock, client_socket, ret; + int sock = -1, client_socket, ret, err = -1; /* * structure to poll for incoming data on communication socket avoids * making blocking sockets. @@ -1027,6 +2985,14 @@ void *lttng_consumer_thread_receive_fds(void *data) rcu_register_thread(); + health_register(health_consumerd, HEALTH_CONSUMERD_TYPE_SESSIOND); + + if (testpoint(consumerd_thread_sessiond)) { + goto error_testpoint; + } + + health_code_update(); + DBG("Creating command socket %s", ctx->consumer_command_sock_path); unlink(ctx->consumer_command_sock_path); client_socket = lttcomm_create_unix_sock(ctx->consumer_command_sock_path); @@ -1041,68 +3007,104 @@ void *lttng_consumer_thread_receive_fds(void *data) } DBG("Sending ready command to lttng-sessiond"); - ret = lttng_consumer_send_error(ctx, CONSUMERD_COMMAND_SOCK_READY); + ret = lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_COMMAND_SOCK_READY); /* return < 0 on error, but == 0 is not fatal */ if (ret < 0) { ERR("Error sending ready command to lttng-sessiond"); goto end; } - ret = fcntl(client_socket, F_SETFL, O_NONBLOCK); - if (ret < 0) { - perror("fcntl O_NONBLOCK"); - goto end; - } - /* prepare the FDs to poll : to client socket and the should_quit pipe */ consumer_sockpoll[0].fd = ctx->consumer_should_quit[0]; consumer_sockpoll[0].events = POLLIN | POLLPRI; consumer_sockpoll[1].fd = client_socket; consumer_sockpoll[1].events = POLLIN | POLLPRI; - if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) { + ret = lttng_consumer_poll_socket(consumer_sockpoll); + if (ret) { + if (ret > 0) { + /* should exit */ + err = 0; + } goto end; } DBG("Connection on client_socket"); /* Blocking call, waiting for transmission */ sock = lttcomm_accept_unix_sock(client_socket); - if (sock <= 0) { + if (sock < 0) { WARN("On accept"); goto end; } - ret = fcntl(sock, F_SETFL, O_NONBLOCK); - if (ret < 0) { - perror("fcntl O_NONBLOCK"); + + /* + * Setup metadata socket which is the second socket connection on the + * command unix socket. + */ + ret = set_metadata_socket(ctx, consumer_sockpoll, client_socket); + if (ret) { + if (ret > 0) { + /* should exit */ + err = 0; + } goto end; } + /* This socket is not useful anymore. */ + ret = close(client_socket); + if (ret < 0) { + PERROR("close client_socket"); + } + client_socket = -1; + /* update the polling structure to poll on the established socket */ consumer_sockpoll[1].fd = sock; consumer_sockpoll[1].events = POLLIN | POLLPRI; while (1) { - if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) { + health_code_update(); + + health_poll_entry(); + ret = lttng_consumer_poll_socket(consumer_sockpoll); + health_poll_exit(); + if (ret) { + if (ret > 0) { + /* should exit */ + err = 0; + } goto end; } DBG("Incoming command on sock"); ret = lttng_consumer_recv_cmd(ctx, sock, consumer_sockpoll); - if (ret == -ENOENT) { - DBG("Received STOP command"); - goto end; - } - if (ret < 0) { - ERR("Communication interrupted on command socket"); + if (ret <= 0) { + /* + * This could simply be a session daemon quitting. Don't output + * ERR() here. + */ + DBG("Communication interrupted on command socket"); + err = 0; goto end; } if (consumer_quit) { DBG("consumer_thread_receive_fds received quit from signal"); + err = 0; /* All is OK */ goto end; } - DBG("received fds on sock"); + DBG("received command on sock"); } + /* All is OK */ + err = 0; + end: - DBG("consumer_thread_receive_fds exiting"); + DBG("Consumer thread sessiond poll exiting"); + + /* + * Close metadata streams since the producer is the session daemon which + * just died. + * + * NOTE: for now, this only applies to the UST tracer. + */ + lttng_consumer_close_all_metadata(); /* * when all fds have hung up, the polling thread @@ -1111,35 +3113,71 @@ end: consumer_quit = 1; /* - * 2s of grace period, if no polling events occur during - * this period, the polling thread will exit even if there - * are still open FDs (should not happen, but safety mechanism). + * Notify the data poll thread to poll back again and test the + * consumer_quit state that we just set so to quit gracefully. */ - consumer_poll_timeout = LTTNG_CONSUMER_POLL_TIMEOUT; + notify_thread_lttng_pipe(ctx->consumer_data_pipe); - /* wake up the polling thread */ - ret = write(ctx->consumer_poll_pipe[1], "4", 1); - if (ret < 0) { - perror("poll pipe write"); + notify_channel_pipe(ctx, NULL, -1, CONSUMER_CHANNEL_QUIT); + + notify_health_quit_pipe(health_quit_pipe); + + /* Cleaning up possibly open sockets. */ + if (sock >= 0) { + ret = close(sock); + if (ret < 0) { + PERROR("close sock sessiond poll"); + } + } + if (client_socket >= 0) { + ret = close(client_socket); + if (ret < 0) { + PERROR("close client_socket sessiond poll"); + } } + +error_testpoint: + if (err) { + health_error(); + ERR("Health error occurred in %s", __func__); + } + health_unregister(health_consumerd); + rcu_unregister_thread(); return NULL; } -int lttng_consumer_read_subbuffer(struct lttng_consumer_stream *stream, +ssize_t lttng_consumer_read_subbuffer(struct lttng_consumer_stream *stream, struct lttng_consumer_local_data *ctx) { + ssize_t ret; + + pthread_mutex_lock(&stream->lock); + if (stream->metadata_flag) { + pthread_mutex_lock(&stream->metadata_rdv_lock); + } + switch (consumer_data.type) { case LTTNG_CONSUMER_KERNEL: - return lttng_kconsumer_read_subbuffer(stream, ctx); + ret = lttng_kconsumer_read_subbuffer(stream, ctx); + break; case LTTNG_CONSUMER32_UST: case LTTNG_CONSUMER64_UST: - return lttng_ustconsumer_read_subbuffer(stream, ctx); + ret = lttng_ustconsumer_read_subbuffer(stream, ctx); + break; default: ERR("Unknown consumer_data type"); assert(0); - return -ENOSYS; + ret = -ENOSYS; + break; + } + + if (stream->metadata_flag) { + pthread_cond_broadcast(&stream->metadata_rdv); + pthread_mutex_unlock(&stream->metadata_rdv_lock); } + pthread_mutex_unlock(&stream->lock); + return ret; } int lttng_consumer_on_recv_stream(struct lttng_consumer_stream *stream) @@ -1160,9 +3198,475 @@ int lttng_consumer_on_recv_stream(struct lttng_consumer_stream *stream) /* * Allocate and set consumer data hash tables. */ -void lttng_consumer_init(void) +int lttng_consumer_init(void) +{ + consumer_data.channel_ht = lttng_ht_new(0, LTTNG_HT_TYPE_U64); + if (!consumer_data.channel_ht) { + goto error; + } + + consumer_data.relayd_ht = lttng_ht_new(0, LTTNG_HT_TYPE_U64); + if (!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) { + 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) { + goto error; + } + + data_ht = lttng_ht_new(0, LTTNG_HT_TYPE_U64); + if (!data_ht) { + goto error; + } + + metadata_ht = lttng_ht_new(0, LTTNG_HT_TYPE_U64); + if (!metadata_ht) { + goto error; + } + + return 0; + +error: + return -1; +} + +/* + * Process the ADD_RELAYD command receive by a consumer. + * + * This will create a relayd socket pair and add it to the relayd hash table. + * The caller MUST acquire a RCU read side lock before calling it. + */ +int consumer_add_relayd_socket(uint64_t net_seq_idx, int sock_type, + struct lttng_consumer_local_data *ctx, int sock, + struct pollfd *consumer_sockpoll, + struct lttcomm_relayd_sock *relayd_sock, uint64_t sessiond_id, + uint64_t relayd_session_id) +{ + int fd = -1, ret = -1, relayd_created = 0; + enum lttcomm_return_code ret_code = LTTCOMM_CONSUMERD_SUCCESS; + struct consumer_relayd_sock_pair *relayd = NULL; + + assert(ctx); + 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); + /* Not found. Allocate one. */ + relayd = consumer_allocate_relayd_sock_pair(net_seq_idx); + if (relayd == NULL) { + ret = -ENOMEM; + ret_code = LTTCOMM_CONSUMERD_ENOMEM; + goto error; + } else { + relayd->sessiond_session_id = sessiond_id; + relayd_created = 1; + } + + /* + * This code path MUST continue to the consumer send status message to + * we can notify the session daemon and continue our work without + * killing everything. + */ + } else { + /* + * relayd key should never be found for control socket. + */ + assert(sock_type != LTTNG_STREAM_CONTROL); + } + + /* First send a status message before receiving the fds. */ + ret = consumer_send_status_msg(sock, LTTCOMM_CONSUMERD_SUCCESS); + if (ret < 0) { + /* Somehow, the session daemon is not responding anymore. */ + lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_FATAL); + goto error_nosignal; + } + + /* Poll on consumer socket. */ + ret = lttng_consumer_poll_socket(consumer_sockpoll); + if (ret) { + /* Needing to exit in the middle of a command: error. */ + lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_POLL_ERROR); + ret = -EINTR; + goto error_nosignal; + } + + /* Get relayd socket from session daemon */ + ret = lttcomm_recv_fds_unix_sock(sock, &fd, 1); + if (ret != sizeof(fd)) { + ret = -1; + fd = -1; /* Just in case it gets set with an invalid value. */ + + /* + * Failing to receive FDs might indicate a major problem such as + * reaching a fd limit during the receive where the kernel returns a + * MSG_CTRUNC and fails to cleanup the fd in the queue. Any case, we + * don't take any chances and stop everything. + * + * XXX: Feature request #558 will fix that and avoid this possible + * issue when reaching the fd limit. + */ + lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_FD); + ret_code = LTTCOMM_CONSUMERD_ERROR_RECV_FD; + goto error; + } + + /* Copy socket information and received FD */ + switch (sock_type) { + case LTTNG_STREAM_CONTROL: + /* Copy received lttcomm socket */ + lttcomm_copy_sock(&relayd->control_sock.sock, &relayd_sock->sock); + ret = lttcomm_create_sock(&relayd->control_sock.sock); + /* Handle create_sock error. */ + if (ret < 0) { + ret_code = LTTCOMM_CONSUMERD_ENOMEM; + goto error; + } + /* + * Close the socket created internally by + * lttcomm_create_sock, so we can replace it by the one + * received from sessiond. + */ + if (close(relayd->control_sock.sock.fd)) { + PERROR("close"); + } + + /* Assign new file descriptor */ + relayd->control_sock.sock.fd = fd; + fd = -1; /* For error path */ + /* Assign version values. */ + relayd->control_sock.major = relayd_sock->major; + relayd->control_sock.minor = relayd_sock->minor; + + relayd->relayd_session_id = relayd_session_id; + + break; + case LTTNG_STREAM_DATA: + /* Copy received lttcomm socket */ + lttcomm_copy_sock(&relayd->data_sock.sock, &relayd_sock->sock); + ret = lttcomm_create_sock(&relayd->data_sock.sock); + /* Handle create_sock error. */ + if (ret < 0) { + ret_code = LTTCOMM_CONSUMERD_ENOMEM; + goto error; + } + /* + * Close the socket created internally by + * lttcomm_create_sock, so we can replace it by the one + * received from sessiond. + */ + if (close(relayd->data_sock.sock.fd)) { + PERROR("close"); + } + + /* Assign new file descriptor */ + relayd->data_sock.sock.fd = fd; + fd = -1; /* for eventual error paths */ + /* Assign version values. */ + relayd->data_sock.major = relayd_sock->major; + relayd->data_sock.minor = relayd_sock->minor; + break; + default: + ERR("Unknown relayd socket type (%d)", sock_type); + ret = -1; + ret_code = LTTCOMM_CONSUMERD_FATAL; + goto error; + } + + DBG("Consumer %s socket created successfully with net idx %" PRIu64 " (fd: %d)", + sock_type == LTTNG_STREAM_CONTROL ? "control" : "data", + relayd->net_seq_idx, fd); + + /* We successfully added the socket. Send status back. */ + ret = consumer_send_status_msg(sock, ret_code); + if (ret < 0) { + /* Somehow, the session daemon is not responding anymore. */ + lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_FATAL); + goto error_nosignal; + } + + /* + * Add relayd socket pair to consumer data hashtable. If object already + * exists or on error, the function gracefully returns. + */ + add_relayd(relayd); + + /* All good! */ + return 0; + +error: + if (consumer_send_status_msg(sock, ret_code) < 0) { + lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_FATAL); + } + +error_nosignal: + /* Close received socket if valid. */ + if (fd >= 0) { + if (close(fd)) { + PERROR("close received socket"); + } + } + + if (relayd_created) { + free(relayd); + } + + return ret; +} + +/* + * Try to lock the stream mutex. + * + * On success, 1 is returned else 0 indicating that the mutex is NOT lock. + */ +static int stream_try_lock(struct lttng_consumer_stream *stream) +{ + int ret; + + assert(stream); + + /* + * Try to lock the stream mutex. On failure, we know that the stream is + * being used else where hence there is data still being extracted. + */ + ret = pthread_mutex_trylock(&stream->lock); + if (ret) { + /* For both EBUSY and EINVAL error, the mutex is NOT locked. */ + ret = 0; + goto end; + } + + ret = 1; + +end: + return ret; +} + +/* + * Search for a relayd associated to the session id and return the reference. + * + * A rcu read side lock MUST be acquire before calling this function and locked + * until the relayd object is no longer necessary. + */ +static struct consumer_relayd_sock_pair *find_relayd_by_session_id(uint64_t id) +{ + struct lttng_ht_iter iter; + 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) { + /* + * Check by sessiond id which is unique here where the relayd session + * id might not be when having multiple relayd. + */ + if (relayd->sessiond_session_id == id) { + /* Found the relayd. There can be only one per id. */ + goto found; + } + } + + return NULL; + +found: + return relayd; +} + +/* + * Check if for a given session id there is still data needed to be extract + * from the buffers. + * + * Return 1 if data is pending or else 0 meaning ready to be read. + */ +int consumer_data_pending(uint64_t id) +{ + int ret; + struct lttng_ht_iter iter; + struct lttng_ht *ht; + struct lttng_consumer_stream *stream; + struct consumer_relayd_sock_pair *relayd = NULL; + int (*data_pending)(struct lttng_consumer_stream *); + + DBG("Consumer data pending command on session id %" PRIu64, id); + + rcu_read_lock(); + pthread_mutex_lock(&consumer_data.lock); + + switch (consumer_data.type) { + case LTTNG_CONSUMER_KERNEL: + data_pending = lttng_kconsumer_data_pending; + break; + case LTTNG_CONSUMER32_UST: + case LTTNG_CONSUMER64_UST: + data_pending = lttng_ustconsumer_data_pending; + break; + default: + ERR("Unknown consumer data type"); + assert(0); + } + + /* Ease our life a bit */ + ht = consumer_data.stream_list_ht; + + relayd = find_relayd_by_session_id(id); + if (relayd) { + /* Send init command for data pending. */ + pthread_mutex_lock(&relayd->ctrl_sock_mutex); + ret = relayd_begin_data_pending(&relayd->control_sock, + relayd->relayd_session_id); + pthread_mutex_unlock(&relayd->ctrl_sock_mutex); + if (ret < 0) { + /* Communication error thus the relayd so no data pending. */ + goto data_not_pending; + } + } + + cds_lfht_for_each_entry_duplicate(ht->ht, + ht->hash_fct(&id, lttng_ht_seed), + ht->match_fct, &id, + &iter.iter, stream, node_session_id.node) { + /* If this call fails, the stream is being used hence data pending. */ + ret = stream_try_lock(stream); + if (!ret) { + goto data_pending; + } + + /* + * A removed node from the hash table indicates that the stream has + * been deleted thus having a guarantee that the buffers are closed + * on the consumer side. However, data can still be transmitted + * over the network so don't skip the relayd check. + */ + ret = cds_lfht_is_node_deleted(&stream->node.node); + if (!ret) { + /* Check the stream if there is data in the buffers. */ + ret = data_pending(stream); + if (ret == 1) { + pthread_mutex_unlock(&stream->lock); + goto data_pending; + } + } + + /* Relayd check */ + if (relayd) { + pthread_mutex_lock(&relayd->ctrl_sock_mutex); + if (stream->metadata_flag) { + ret = relayd_quiescent_control(&relayd->control_sock, + stream->relayd_stream_id); + } else { + ret = relayd_data_pending(&relayd->control_sock, + stream->relayd_stream_id, + stream->next_net_seq_num - 1); + } + pthread_mutex_unlock(&relayd->ctrl_sock_mutex); + if (ret == 1) { + pthread_mutex_unlock(&stream->lock); + goto data_pending; + } + } + pthread_mutex_unlock(&stream->lock); + } + + if (relayd) { + unsigned int is_data_inflight = 0; + + /* Send init command for data pending. */ + pthread_mutex_lock(&relayd->ctrl_sock_mutex); + ret = relayd_end_data_pending(&relayd->control_sock, + relayd->relayd_session_id, &is_data_inflight); + pthread_mutex_unlock(&relayd->ctrl_sock_mutex); + if (ret < 0) { + goto data_not_pending; + } + if (is_data_inflight) { + goto data_pending; + } + } + + /* + * Finding _no_ node in the hash table and no inflight data means that the + * stream(s) have been removed thus data is guaranteed to be available for + * analysis from the trace files. + */ + +data_not_pending: + /* Data is available to be read by a viewer. */ + pthread_mutex_unlock(&consumer_data.lock); + rcu_read_unlock(); + return 0; + +data_pending: + /* Data is still being extracted from buffers. */ + pthread_mutex_unlock(&consumer_data.lock); + rcu_read_unlock(); + return 1; +} + +/* + * Send a ret code status message to the sessiond daemon. + * + * Return the sendmsg() return value. + */ +int consumer_send_status_msg(int sock, int ret_code) +{ + struct lttcomm_consumer_status_msg msg; + + memset(&msg, 0, sizeof(msg)); + msg.ret_code = ret_code; + + return lttcomm_send_unix_sock(sock, &msg, sizeof(msg)); +} + +/* + * Send a channel status message to the sessiond daemon. + * + * Return the sendmsg() return value. + */ +int consumer_send_status_channel(int sock, + struct lttng_consumer_channel *channel) { - consumer_data.stream_ht = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG); - consumer_data.channel_ht = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG); + struct lttcomm_consumer_status_channel msg; + + assert(sock >= 0); + + memset(&msg, 0, sizeof(msg)); + if (!channel) { + msg.ret_code = LTTCOMM_CONSUMERD_CHANNEL_FAIL; + } else { + msg.ret_code = LTTCOMM_CONSUMERD_SUCCESS; + msg.key = channel->key; + msg.stream_count = channel->streams.count; + } + + return lttcomm_send_unix_sock(sock, &msg, sizeof(msg)); } +/* + * Using a maximum stream size with the produced and consumed position of a + * stream, computes the new consumed position to be as close as possible to the + * maximum possible stream size. + * + * If maximum stream size is lower than the possible buffer size (produced - + * consumed), the consumed_pos given is returned untouched else the new value + * is returned. + */ +unsigned long consumer_get_consumed_maxsize(unsigned long consumed_pos, + unsigned long produced_pos, uint64_t max_stream_size) +{ + if (max_stream_size && max_stream_size < (produced_pos - consumed_pos)) { + /* Offset from the produced position to get the latest buffers. */ + return produced_pos - max_stream_size; + } + + return consumed_pos; +}