Relayd data available command support
[lttng-tools.git] / src / bin / lttng-relayd / main.c
index cb115afda0ede578de51c9302b5380f4bd2bf671..0f81d556dd4df73a910471756b75cf6567581a36 100644 (file)
@@ -472,12 +472,6 @@ void *relay_thread_listener(void *data)
        struct lttng_poll_event events;
        struct lttcomm_sock *control_sock, *data_sock;
 
-       /*
-        * Get allocated in this thread, enqueued to a global queue, dequeued and
-        * freed in the worker thread.
-        */
-       struct relay_command *relay_cmd = NULL;
-
        DBG("[thread] Relay listener started");
 
        control_sock = relay_init_sock(control_uri);
@@ -544,7 +538,13 @@ restart:
                                ERR("socket poll error");
                                goto error;
                        } else if (revents & LPOLLIN) {
-                               struct lttcomm_sock *newsock = NULL;
+                               /*
+                                * Get allocated in this thread,
+                                * enqueued to a global queue, dequeued
+                                * and freed in the worker thread.
+                                */
+                               struct relay_command *relay_cmd;
+                               struct lttcomm_sock *newsock;
 
                                relay_cmd = zmalloc(sizeof(struct relay_command));
                                if (relay_cmd == NULL) {
@@ -554,16 +554,19 @@ restart:
 
                                if (pollfd == data_sock->fd) {
                                        newsock = data_sock->ops->accept(data_sock);
-                                       if (newsock < 0) {
+                                       if (!newsock) {
                                                PERROR("accepting data sock");
+                                               free(relay_cmd);
                                                goto error;
                                        }
                                        relay_cmd->type = RELAY_DATA;
                                        DBG("Relay data connection accepted, socket %d", newsock->fd);
-                               } else if (pollfd == control_sock->fd) {
+                               } else {
+                                       assert(pollfd == control_sock->fd);
                                        newsock = control_sock->ops->accept(control_sock);
-                                       if (newsock < 0) {
+                                       if (!newsock) {
                                                PERROR("accepting control sock");
+                                               free(relay_cmd);
                                                goto error;
                                        }
                                        relay_cmd->type = RELAY_CONTROL;
@@ -573,6 +576,8 @@ restart:
                                                &val, sizeof(int));
                                if (ret < 0) {
                                        PERROR("setsockopt inet");
+                                       lttcomm_destroy_sock(newsock);
+                                       free(relay_cmd);
                                        goto error;
                                }
                                relay_cmd->sock = newsock;
@@ -977,9 +982,9 @@ end:
        free(root_path);
        /* send the session id to the client or a negative return code on error */
        if (ret < 0) {
-               reply.ret_code = htobe32(LTTCOMM_ERR);
+               reply.ret_code = htobe32(LTTNG_ERR_UNK);
        } else {
-               reply.ret_code = htobe32(LTTCOMM_OK);
+               reply.ret_code = htobe32(LTTNG_OK);
        }
        reply.handle = htobe64(stream->stream_handle);
        send_ret = cmd->sock->ops->sendmsg(cmd->sock, &reply,
@@ -1041,6 +1046,7 @@ int relay_close_stream(struct lttcomm_relayd_hdr *recv_hdr,
                goto end_unlock;
        }
 
+       stream->last_net_seq_num = be64toh(stream_info.last_net_seq_num);
        stream->close_flag = 1;
 
        if (close_stream_check(stream)) {
@@ -1058,9 +1064,9 @@ end_unlock:
        rcu_read_unlock();
 
        if (ret < 0) {
-               reply.ret_code = htobe32(LTTCOMM_ERR);
+               reply.ret_code = htobe32(LTTNG_ERR_UNK);
        } else {
-               reply.ret_code = htobe32(LTTCOMM_OK);
+               reply.ret_code = htobe32(LTTNG_OK);
        }
        send_ret = cmd->sock->ops->sendmsg(cmd->sock, &reply,
                        sizeof(struct lttcomm_relayd_generic_reply), 0);
@@ -1081,7 +1087,7 @@ void relay_unknown_command(struct relay_command *cmd)
        struct lttcomm_relayd_generic_reply reply;
        int ret;
 
-       reply.ret_code = htobe32(LTTCOMM_ERR);
+       reply.ret_code = htobe32(LTTNG_ERR_UNK);
        ret = cmd->sock->ops->sendmsg(cmd->sock, &reply,
                        sizeof(struct lttcomm_relayd_generic_reply), 0);
        if (ret < 0) {
@@ -1097,13 +1103,13 @@ static
 int relay_start(struct lttcomm_relayd_hdr *recv_hdr,
                struct relay_command *cmd)
 {
-       int ret = htobe32(LTTCOMM_OK);
+       int ret = htobe32(LTTNG_OK);
        struct lttcomm_relayd_generic_reply reply;
        struct relay_session *session = cmd->session;
 
        if (!session) {
                DBG("Trying to start the streaming without a session established");
-               ret = htobe32(LTTCOMM_ERR);
+               ret = htobe32(LTTNG_ERR_UNK);
        }
 
        reply.ret_code = ret;
@@ -1144,6 +1150,36 @@ end:
        return ret;
 }
 
+/*
+ * Append padding to the file pointed by the file descriptor fd.
+ */
+static int write_padding_to_file(int fd, uint32_t size)
+{
+       int ret = 0;
+       char *zeros;
+
+       if (size == 0) {
+               goto end;
+       }
+
+       zeros = zmalloc(size);
+       if (zeros == NULL) {
+               PERROR("zmalloc zeros for padding");
+               ret = -1;
+               goto end;
+       }
+
+       do {
+               ret = write(fd, zeros, size);
+       } while (ret < 0 && errno == EINTR);
+       if (ret < 0) {
+               PERROR("write padding to file");
+       }
+
+end:
+       return ret;
+}
+
 /*
  * relay_recv_metadata: receive the metada for the session.
  */
@@ -1151,7 +1187,7 @@ static
 int relay_recv_metadata(struct lttcomm_relayd_hdr *recv_hdr,
                struct relay_command *cmd, struct lttng_ht *streams_ht)
 {
-       int ret = htobe32(LTTCOMM_OK);
+       int ret = htobe32(LTTNG_OK);
        struct relay_session *session = cmd->session;
        struct lttcomm_relayd_metadata_payload *metadata_struct;
        struct relay_stream *metadata_stream;
@@ -1208,6 +1244,13 @@ int relay_recv_metadata(struct lttcomm_relayd_hdr *recv_hdr,
                ret = -1;
                goto end_unlock;
        }
+
+       ret = write_padding_to_file(metadata_stream->fd,
+                       be32toh(metadata_struct->padding_size));
+       if (ret < 0) {
+               goto end_unlock;
+       }
+
        DBG2("Relay metadata written");
 
 end_unlock:
@@ -1223,9 +1266,9 @@ static
 int relay_send_version(struct lttcomm_relayd_hdr *recv_hdr,
                struct relay_command *cmd)
 {
-       int ret = htobe32(LTTCOMM_OK);
+       int ret;
        struct lttcomm_relayd_version reply;
-       struct relay_session *session = NULL;
+       struct relay_session *session;
 
        if (cmd->session == NULL) {
                session = zmalloc(sizeof(struct relay_session));
@@ -1237,10 +1280,17 @@ int relay_send_version(struct lttcomm_relayd_hdr *recv_hdr,
                session->id = ++last_relay_session_id;
                DBG("Created session %" PRIu64, session->id);
                cmd->session = session;
+       } else {
+               session = cmd->session;
        }
        session->version_check_done = 1;
 
-       sscanf(VERSION, "%u.%u", &reply.major, &reply.minor);
+       ret = sscanf(VERSION, "%u.%u", &reply.major, &reply.minor);
+       if (ret < 2) {
+               ERR("Error in scanning version");
+               ret = -1;
+               goto end;
+       }
        reply.major = htobe32(reply.major);
        reply.minor = htobe32(reply.minor);
        ret = cmd->sock->ops->sendmsg(cmd->sock, &reply,
@@ -1255,6 +1305,102 @@ end:
        return ret;
 }
 
+/*
+ * Check for data availability for a given stream id from the session daemon.
+ */
+static
+int relay_data_available(struct lttcomm_relayd_hdr *recv_hdr,
+               struct relay_command *cmd, struct lttng_ht *streams_ht)
+{
+       struct relay_session *session = cmd->session;
+       struct lttcomm_relayd_data_available msg;
+       struct lttcomm_relayd_generic_reply reply;
+       struct relay_stream *stream;
+       int ret;
+       struct lttng_ht_node_ulong *node;
+       struct lttng_ht_iter iter;
+       uint64_t last_net_seq_num, stream_id;
+
+       DBG("Data available command received");
+
+       if (!session || session->version_check_done == 0) {
+               ERR("Trying to check for data before version check");
+               ret = -1;
+               goto end_no_session;
+       }
+
+       ret = cmd->sock->ops->recvmsg(cmd->sock, &msg, sizeof(msg), MSG_WAITALL);
+       if (ret < sizeof(msg)) {
+               ERR("Relay didn't receive valid data_available struct size : %d", ret);
+               ret = -1;
+               goto end_no_session;
+       }
+
+       stream_id = be64toh(msg.stream_id);
+       last_net_seq_num = be64toh(msg.last_net_seq_num);
+
+       rcu_read_lock();
+       lttng_ht_lookup(streams_ht, (void *)((unsigned long) stream_id), &iter);
+       node = lttng_ht_iter_get_node_ulong(&iter);
+       if (node == NULL) {
+               DBG("Relay stream %" PRIu64 " not found", stream_id);
+               ret = -1;
+               goto end_unlock;
+       }
+
+       stream = caa_container_of(node, struct relay_stream, stream_n);
+       assert(stream);
+
+       DBG("Data available for stream id %" PRIu64 " prev_seq %" PRIu64
+                       " and last_seq %" PRIu64, stream_id, stream->prev_seq,
+                       last_net_seq_num);
+
+       if (stream->prev_seq == -1UL || stream->prev_seq <= last_net_seq_num) {
+               /* Data has in fact been written and is available */
+               ret = 1;
+       } else {
+               /* Data still being streamed. */
+               ret = 0;
+       }
+
+end_unlock:
+       rcu_read_unlock();
+
+       reply.ret_code = htobe32(ret);
+       ret = cmd->sock->ops->sendmsg(cmd->sock, &reply, sizeof(reply), 0);
+       if (ret < 0) {
+               ERR("Relay data available ret code failed");
+       }
+
+end_no_session:
+       return ret;
+}
+
+/*
+ * Wait for the control socket to reach a quiescent state.
+ *
+ * Note that for now, when receiving this command from the session daemon, this
+ * means that every subsequent commands or data received on the control socket
+ * has been handled. So, this is why we simply return OK here.
+ */
+static
+int relay_quiescent_control(struct lttcomm_relayd_hdr *recv_hdr,
+               struct relay_command *cmd)
+{
+       int ret;
+       struct lttcomm_relayd_generic_reply reply;
+
+       DBG("Checking quiescent state on control socket");
+
+       reply.ret_code = htobe32(LTTNG_OK);
+       ret = cmd->sock->ops->sendmsg(cmd->sock, &reply, sizeof(reply), 0);
+       if (ret < 0) {
+               ERR("Relay data available ret code failed");
+       }
+
+       return ret;
+}
+
 /*
  * relay_process_control: Process the commands received on the control socket
  */
@@ -1285,6 +1431,12 @@ int relay_process_control(struct lttcomm_relayd_hdr *recv_hdr,
        case RELAYD_CLOSE_STREAM:
                ret = relay_close_stream(recv_hdr, cmd, streams_ht);
                break;
+       case RELAYD_DATA_AVAILABLE:
+               ret = relay_data_available(recv_hdr, cmd, streams_ht);
+               break;
+       case RELAYD_QUIESCENT_CONTROL:
+               ret = relay_quiescent_control(recv_hdr, cmd);
+               break;
        case RELAYD_UPDATE_SYNC_INFO:
        default:
                ERR("Received unknown command (%u)", be32toh(recv_hdr->cmd));
@@ -1357,8 +1509,14 @@ int relay_process_data(struct relay_command *cmd, struct lttng_ht *streams_ht)
                ret = -1;
                goto end_unlock;
        }
+
        DBG2("Relay wrote %d bytes to tracefile for stream id %" PRIu64,
-               ret, stream->stream_handle);
+                       ret, stream->stream_handle);
+
+       ret = write_padding_to_file(stream->fd, be32toh(data_hdr.padding_size));
+       if (ret < 0) {
+               goto end_unlock;
+       }
 
        stream->prev_seq = net_seq_num;
 
@@ -1407,7 +1565,7 @@ int relay_add_connection(int fd, struct lttng_poll_event *events,
                goto error;
        }
        ret = read(fd, relay_connection, sizeof(struct relay_command));
-       if (ret < 0 || ret < sizeof(relay_connection)) {
+       if (ret < 0 || ret < sizeof(struct relay_command)) {
                PERROR("read relay cmd pipe");
                goto error_read;
        }
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