Consumer daemon data available command support
[lttng-tools.git] / src / common / ust-consumer / ust-consumer.c
index 9e1a59f5e447558a127d5ceac8273417131dd59e..1bafeee07daccb79ef8f5377256ec6ed78257018 100644 (file)
@@ -171,7 +171,7 @@ int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
        case LTTNG_CONSUMER_ADD_STREAM:
        {
                struct lttng_consumer_stream *new_stream;
-               int fds[2];
+               int fds[2], stream_pipe;
                size_t nb_fd = 2;
                struct consumer_relayd_sock_pair *relayd = NULL;
                int alloc_ret = 0;
@@ -190,9 +190,8 @@ int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                        return ret;
                }
 
-               DBG("consumer_add_stream chan %d stream %d",
-                               msg.u.stream.channel_key,
-                               msg.u.stream.stream_key);
+               DBG("Consumer command ADD_STREAM chan %d stream %d",
+                               msg.u.stream.channel_key, msg.u.stream.stream_key);
 
                assert(msg.u.stream.output == LTTNG_EVENT_MMAP);
                new_stream = consumer_allocate_stream(msg.u.stream.channel_key,
@@ -206,6 +205,7 @@ int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                                msg.u.stream.gid,
                                msg.u.stream.net_index,
                                msg.u.stream.metadata_flag,
+                               msg.u.stream.session_id,
                                &alloc_ret);
                if (new_stream == NULL) {
                        switch (alloc_ret) {
@@ -235,42 +235,44 @@ int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                                        &new_stream->relayd_stream_id);
                        pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
                        if (ret < 0) {
+                               consumer_del_stream(new_stream, NULL);
                                goto end_nosignal;
                        }
                } else if (msg.u.stream.net_index != -1) {
                        ERR("Network sequence index %d unknown. Not adding stream.",
                                        msg.u.stream.net_index);
-                       free(new_stream);
+                       consumer_del_stream(new_stream, NULL);
                        goto end_nosignal;
                }
 
-               /* Send stream to the metadata thread */
-               if (new_stream->metadata_flag) {
-                       if (ctx->on_recv_stream) {
-                               ret = ctx->on_recv_stream(new_stream);
-                               if (ret < 0) {
-                                       goto end_nosignal;
-                               }
-                       }
-
-                       do {
-                               ret = write(ctx->consumer_metadata_pipe[1], new_stream,
-                                               sizeof(struct lttng_consumer_stream));
-                       } while (ret < 0 && errno == EINTR);
+               /* Do actions once stream has been received. */
+               if (ctx->on_recv_stream) {
+                       ret = ctx->on_recv_stream(new_stream);
                        if (ret < 0) {
-                               PERROR("write metadata pipe");
+                               consumer_del_stream(new_stream, NULL);
+                               goto end_nosignal;
                        }
+               }
+
+               /* Get the right pipe where the stream will be sent. */
+               if (new_stream->metadata_flag) {
+                       stream_pipe = ctx->consumer_metadata_pipe[1];
                } else {
-                       if (ctx->on_recv_stream) {
-                               ret = ctx->on_recv_stream(new_stream);
-                               if (ret < 0) {
-                                       goto end_nosignal;
-                               }
-                       }
-                       consumer_add_stream(new_stream);
+                       stream_pipe = ctx->consumer_data_pipe[1];
                }
 
-               DBG("UST consumer_add_stream %s (%d,%d) with relayd id %" PRIu64,
+               do {
+                       ret = write(stream_pipe, &new_stream, sizeof(new_stream));
+               } while (ret < 0 && errno == EINTR);
+               if (ret < 0) {
+                       PERROR("Consumer write %s stream to pipe %d",
+                                       new_stream->metadata_flag ? "metadata" : "data",
+                                       stream_pipe);
+                       consumer_del_stream(new_stream, NULL);
+                       goto end_nosignal;
+               }
+
+               DBG("UST consumer ADD_STREAM %s (%d,%d) with relayd id %" PRIu64,
                                msg.u.stream.path_name, fds[0], fds[1],
                                new_stream->relayd_stream_id);
                break;
@@ -307,39 +309,27 @@ int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
        {
                rcu_read_unlock();
                return -ENOSYS;
-#if 0
-               if (ctx->on_update_stream != NULL) {
-                       ret = ctx->on_update_stream(msg.u.stream.stream_key, msg.u.stream.state);
-                       if (ret == 0) {
-                               consumer_change_stream_state(msg.u.stream.stream_key, msg.u.stream.state);
-                       } else if (ret < 0) {
-                               goto end;
-                       }
-               } else {
-                       consumer_change_stream_state(msg.u.stream.stream_key,
-                               msg.u.stream.state);
+       }
+       case LTTNG_CONSUMER_DATA_AVAILABLE:
+       {
+               int32_t ret;
+               uint64_t id = msg.u.data_available.session_id;
+
+               DBG("UST consumer data available command for id %" PRIu64, id);
+
+               ret = consumer_data_available(id);
+
+               /* Send back returned value to session daemon */
+               ret = lttcomm_send_unix_sock(sock, &ret, sizeof(ret));
+               if (ret < 0) {
+                       PERROR("send data available ret code");
                }
                break;
-#endif
        }
        default:
                break;
        }
 
-       /*
-        * Wake-up the other end by writing a null byte in the pipe (non-blocking).
-        * Important note: Because writing into the pipe is non-blocking (and
-        * therefore we allow dropping wakeup data, as long as there is wakeup data
-        * present in the pipe buffer to wake up the other end), the other end
-        * should perform the following sequence for waiting:
-        *
-        * 1) empty the pipe (reads).
-        * 2) perform update operation.
-        * 3) wait on the pipe (poll).
-        */
-       do {
-               ret = write(ctx->consumer_poll_pipe[1], "", 1);
-       } while (ret < 0 && errno == EINTR);
 end_nosignal:
        rcu_read_unlock();
 
@@ -379,7 +369,7 @@ void lttng_ustconsumer_del_channel(struct lttng_consumer_channel *chan)
        ustctl_unmap_channel(chan->handle);
 }
 
-int lttng_ustconsumer_allocate_stream(struct lttng_consumer_stream *stream)
+int lttng_ustconsumer_add_stream(struct lttng_consumer_stream *stream)
 {
        struct lttng_ust_object_data obj;
        int ret;
@@ -389,21 +379,35 @@ int lttng_ustconsumer_allocate_stream(struct lttng_consumer_stream *stream)
        obj.wait_fd = stream->wait_fd;
        obj.memory_map_size = stream->mmap_len;
        ret = ustctl_add_stream(stream->chan->handle, &obj);
-       if (ret)
-               return ret;
+       if (ret) {
+               ERR("UST ctl add_stream failed with ret %d", ret);
+               goto error;
+       }
+
        stream->buf = ustctl_open_stream_read(stream->chan->handle, stream->cpu);
-       if (!stream->buf)
-               return -EBUSY;
+       if (!stream->buf) {
+               ERR("UST ctl open_stream_read failed");
+               ret = -EBUSY;
+               goto error;
+       }
+
        /* ustctl_open_stream_read has closed the shm fd. */
        stream->wait_fd_is_copy = 1;
        stream->shm_fd = -1;
 
        stream->mmap_base = ustctl_get_mmap_base(stream->chan->handle, stream->buf);
        if (!stream->mmap_base) {
-               return -EINVAL;
+               ERR("UST ctl get_mmap_base failed");
+               ret = -EINVAL;
+               goto mmap_error;
        }
 
        return 0;
+
+mmap_error:
+       ustctl_close_stream_read(stream->chan->handle, stream->buf);
+error:
+       return ret;
 }
 
 void lttng_ustconsumer_del_stream(struct lttng_consumer_stream *stream)
@@ -481,7 +485,6 @@ int lttng_ustconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
                ERR("Error writing to tracefile "
                                "(ret: %zd != len: %lu != subbuf_size: %lu)",
                                ret, len, subbuf_size);
-
        }
        err = ustctl_put_next_subbuf(handle, buf);
        assert(err == 0);
@@ -507,9 +510,56 @@ int lttng_ustconsumer_on_recv_stream(struct lttng_consumer_stream *stream)
                stream->out_fd = ret;
        }
 
+       ret = lttng_ustconsumer_add_stream(stream);
+       if (ret) {
+               consumer_del_stream(stream, NULL);
+               ret = -1;
+               goto error;
+       }
+
        /* we return 0 to let the library handle the FD internally */
        return 0;
 
 error:
        return ret;
 }
+
+/*
+ * Check if data is still being extracted from the buffers for a specific
+ * stream. Consumer data lock MUST be acquired before calling this function.
+ *
+ * Return 0 if the traced data are still getting read else 1 meaning that the
+ * data is available for trace viewer reading.
+ */
+int lttng_ustconsumer_data_available(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 == EBUSY) {
+               goto data_not_available;
+       }
+       /* The stream is now locked so we can do our ustctl calls */
+
+       ret = ustctl_get_next_subbuf(stream->chan->handle, stream->buf);
+       if (ret == 0) {
+               /* There is still data so let's put back this subbuffer. */
+               ret = ustctl_put_subbuf(stream->chan->handle, stream->buf);
+               assert(ret == 0);
+               pthread_mutex_unlock(&stream->lock);
+               goto data_not_available;
+       }
+
+       /* Data is available to be read for this stream. */
+       pthread_mutex_unlock(&stream->lock);
+       return 1;
+
+data_not_available:
+       return 0;
+}
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