Consumer: implement LTTNG_CONSUMER_CLEAR_CHANNEL
[lttng-tools.git] / src / common / ust-consumer / ust-consumer.c
index 147fe8aafe899a092a91ee8be58357786d7f074f..2c8065d9b1512dc4af1bb6fda8ad0151293cd324 100644 (file)
@@ -51,7 +51,6 @@
 
 extern struct lttng_consumer_global_data consumer_data;
 extern int consumer_poll_timeout;
-extern volatile int consumer_quit;
 
 /*
  * Free channel object and all streams associated with it. This MUST be used
@@ -832,6 +831,7 @@ static int close_metadata(uint64_t chan_key)
 {
        int ret = 0;
        struct lttng_consumer_channel *channel;
+       unsigned int channel_monitor;
 
        DBG("UST consumer close metadata key %" PRIu64, chan_key);
 
@@ -850,13 +850,48 @@ static int close_metadata(uint64_t chan_key)
 
        pthread_mutex_lock(&consumer_data.lock);
        pthread_mutex_lock(&channel->lock);
-
+       channel_monitor = channel->monitor;
        if (cds_lfht_is_node_deleted(&channel->node.node)) {
                goto error_unlock;
        }
 
        lttng_ustconsumer_close_metadata(channel);
+       pthread_mutex_unlock(&channel->lock);
+       pthread_mutex_unlock(&consumer_data.lock);
 
+       /*
+        * The ownership of a metadata channel depends on the type of
+        * session to which it belongs. In effect, the monitor flag is checked
+        * to determine if this metadata channel is in "snapshot" mode or not.
+        *
+        * In the non-snapshot case, the metadata channel is created along with
+        * a single stream which will remain present until the metadata channel
+        * is destroyed (on the destruction of its session). In this case, the
+        * metadata stream in "monitored" by the metadata poll thread and holds
+        * the ownership of its channel.
+        *
+        * Closing the metadata will cause the metadata stream's "metadata poll
+        * pipe" to be closed. Closing this pipe will wake-up the metadata poll
+        * thread which will teardown the metadata stream which, in return,
+        * deletes the metadata channel.
+        *
+        * In the snapshot case, the metadata stream is created and destroyed
+        * on every snapshot record. Since the channel doesn't have an owner
+        * other than the session daemon, it is safe to destroy it immediately
+        * on reception of the CLOSE_METADATA command.
+        */
+       if (!channel_monitor) {
+               /*
+                * The channel and consumer_data locks must be
+                * released before this call since consumer_del_channel
+                * re-acquires the channel and consumer_data locks to teardown
+                * the channel and queue its reclamation by the "call_rcu"
+                * worker thread.
+                */
+               consumer_del_channel(channel);
+       }
+
+       return ret;
 error_unlock:
        pthread_mutex_unlock(&channel->lock);
        pthread_mutex_unlock(&consumer_data.lock);
@@ -1077,9 +1112,6 @@ static int snapshot_channel(uint64_t key, char *path, uint64_t relayd_id,
        DBG("UST consumer snapshot channel %" PRIu64, key);
 
        cds_list_for_each_entry(stream, &channel->streams.head, send_node) {
-               /* Are we at a position _before_ the first available packet ? */
-               bool before_first_packet = true;
-
                health_code_update();
 
                /* Lock stream because we are about to change its state. */
@@ -1105,12 +1137,6 @@ static int snapshot_channel(uint64_t key, char *path, uint64_t relayd_id,
                        DBG("UST consumer snapshot stream %s/%s (%" PRIu64 ")", path,
                                        stream->name, stream->key);
                }
-               if (relayd_id != -1ULL) {
-                       ret = consumer_send_relayd_streams_sent(relayd_id);
-                       if (ret < 0) {
-                               goto error_unlock;
-                       }
-               }
 
                /*
                 * If tracing is active, we want to perform a "full" buffer flush.
@@ -1151,7 +1177,6 @@ static int snapshot_channel(uint64_t key, char *path, uint64_t relayd_id,
                while (consumed_pos < produced_pos) {
                        ssize_t read_len;
                        unsigned long len, padded_len;
-                       int lost_packet = 0;
 
                        health_code_update();
 
@@ -1165,15 +1190,7 @@ static int snapshot_channel(uint64_t key, char *path, uint64_t relayd_id,
                                }
                                DBG("UST consumer get subbuf failed. Skipping it.");
                                consumed_pos += stream->max_sb_size;
-
-                               /*
-                                * Start accounting lost packets only when we
-                                * already have extracted packets (to match the
-                                * content of the final snapshot).
-                                */
-                               if (!before_first_packet) {
-                                       lost_packet = 1;
-                               }
+                               stream->chan->lost_packets++;
                                continue;
                        }
 
@@ -1209,16 +1226,6 @@ static int snapshot_channel(uint64_t key, char *path, uint64_t relayd_id,
                                goto error_close_stream;
                        }
                        consumed_pos += stream->max_sb_size;
-
-                       /*
-                        * Only account lost packets located between
-                        * succesfully extracted packets (do not account before
-                        * and after since they are not visible in the
-                        * resulting snapshot).
-                        */
-                       stream->chan->lost_packets += lost_packet;
-                       lost_packet = 0;
-                       before_first_packet = false;
                }
 
                /* Simply close the stream so we can use it on the next snapshot. */
@@ -1355,7 +1362,7 @@ int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
        case LTTNG_CONSUMER_ADD_RELAYD_SOCKET:
        {
                /* Session daemon status message are handled in the following call. */
-               ret = consumer_add_relayd_socket(msg.u.relayd_sock.net_index,
+               consumer_add_relayd_socket(msg.u.relayd_sock.net_index,
                                msg.u.relayd_sock.type, ctx, sock, consumer_sockpoll,
                                &msg.u.relayd_sock.sock, msg.u.relayd_sock.session_id,
                                msg.u.relayd_sock.relayd_session_id);
@@ -1456,6 +1463,7 @@ int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                attr.read_timer_interval = msg.u.ask_channel.read_timer_interval;
                attr.chan_id = msg.u.ask_channel.chan_id;
                memcpy(attr.uuid, msg.u.ask_channel.uuid, sizeof(attr.uuid));
+               attr.blocking_timeout= msg.u.ask_channel.blocking_timeout;
 
                /* Match channel buffer type to the UST abi. */
                switch (msg.u.ask_channel.output) {
@@ -1915,6 +1923,31 @@ int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                }
                goto end_msg_sessiond;
        }
+       case LTTNG_CONSUMER_CLEAR_CHANNEL:
+       {
+               struct lttng_consumer_channel *channel;
+               uint64_t key = msg.u.clear_channel.key;
+
+               channel = consumer_find_channel(key);
+               if (!channel) {
+                       DBG("Channel %" PRIu64 " not found", key);
+                       ret_code = LTTCOMM_CONSUMERD_CHAN_NOT_FOUND;
+               } else {
+                       ret = lttng_consumer_clear_channel(channel);
+                       if (ret) {
+                               ERR("Clear channel failed");
+                               ret_code = ret;
+                       }
+
+                       health_code_update();
+               }
+               ret = consumer_send_status_msg(sock, ret_code);
+               if (ret < 0) {
+                       /* Somehow, the session daemon is not responding anymore. */
+                       goto end_nosignal;
+               }
+               break;
+       }
        default:
                break;
        }
@@ -2061,6 +2094,14 @@ void lttng_ustconsumer_flush_buffer(struct lttng_consumer_stream *stream,
        ustctl_flush_buffer(stream->ustream, producer);
 }
 
+void lttng_ustconsumer_clear_buffer(struct lttng_consumer_stream *stream)
+{
+       assert(stream);
+       assert(stream->ustream);
+
+       ustctl_clear_buffer(stream->ustream);
+}
+
 int lttng_ustconsumer_get_current_timestamp(
                struct lttng_consumer_stream *stream, uint64_t *ts)
 {
@@ -2914,7 +2955,7 @@ int lttng_ustconsumer_request_metadata(struct lttng_consumer_local_data *ctx,
        request.key = channel->key;
 
        DBG("Sending metadata request to sessiond, session id %" PRIu64
-                       ", per-pid %" PRIu64 ", app UID %u and channek key %" PRIu64,
+                       ", per-pid %" PRIu64 ", app UID %u and channel key %" PRIu64,
                        request.session_id, request.session_id_per_pid, request.uid,
                        request.key);
 
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