Fix: notify the viewer if new streams got added
[lttng-tools.git] / src / bin / lttng-relayd / live.c
index 480c459ce6a49724f54d1b6ef71c0b5a6d458a1b..1a691a849c11e972fee17059df4d5c7068846f01 100644 (file)
 #include "lttng-viewer.h"
 #include "utils.h"
 #include "health-relayd.h"
+#include "testpoint.h"
 
 static struct lttng_uri *live_uri;
 
-/*
- * Quit pipe for all threads. This permits a single cancellation point
- * for all threads when receiving an event on the pipe.
- */
-static int live_thread_quit_pipe[2] = { -1, -1 };
-
 /*
  * This pipe is used to inform the worker thread that a command is queued and
  * ready to be processed.
@@ -126,7 +121,7 @@ void stop_threads(void)
 
        /* Stopping all threads */
        DBG("Terminating all live threads");
-       ret = notify_thread_pipe(live_thread_quit_pipe[1]);
+       ret = notify_thread_pipe(thread_quit_pipe[1]);
        if (ret < 0) {
                ERR("write error on thread quit pipe");
        }
@@ -155,7 +150,7 @@ int create_thread_poll_set(struct lttng_poll_event *events, int size)
        }
 
        /* Add quit pipe */
-       ret = lttng_poll_add(events, live_thread_quit_pipe[0], LPOLLIN);
+       ret = lttng_poll_add(events, thread_quit_pipe[0], LPOLLIN | LPOLLERR);
        if (ret < 0) {
                goto error;
        }
@@ -174,7 +169,7 @@ error:
 static
 int check_thread_quit_pipe(int fd, uint32_t events)
 {
-       if (fd == live_thread_quit_pipe[0] && (events & LPOLLIN)) {
+       if (fd == thread_quit_pipe[0] && (events & LPOLLIN)) {
                return 1;
        }
 
@@ -245,9 +240,7 @@ void *thread_listener(void *data)
                goto error_sock_control;
        }
 
-       /*
-        * Pass 3 as size here for the thread quit pipe, control and data socket.
-        */
+       /* Pass 2 as size here for the thread quit pipe and control sockets. */
        ret = create_thread_poll_set(&events, 2);
        if (ret < 0) {
                goto error_create_poll;
@@ -259,6 +252,12 @@ void *thread_listener(void *data)
                goto error_poll_add;
        }
 
+       lttng_relay_notify_ready();
+
+       if (testpoint(relayd_thread_live_listener)) {
+               goto error_testpoint;
+       }
+
        while (1) {
                health_code_update();
 
@@ -346,6 +345,7 @@ restart:
 exit:
 error:
 error_poll_add:
+error_testpoint:
        lttng_poll_clean(&events);
 error_create_poll:
        if (live_control_sock->fd >= 0) {
@@ -381,6 +381,10 @@ void *thread_dispatcher(void *data)
 
        health_register(health_relayd, HEALTH_RELAYD_TYPE_LIVE_DISPATCHER);
 
+       if (testpoint(relayd_thread_live_dispatcher)) {
+               goto error_testpoint;
+       }
+
        health_code_update();
 
        while (!CMM_LOAD_SHARED(live_dispatch_thread_exit)) {
@@ -429,6 +433,7 @@ void *thread_dispatcher(void *data)
        err = 0;
 
 error:
+error_testpoint:
        if (err) {
                health_error();
                ERR("Health error occurred in %s", __func__);
@@ -478,7 +483,7 @@ int viewer_connect(struct relay_command *cmd)
        if (reply.major != be32toh(msg.major)) {
                DBG("Incompatible major versions (%u vs %u)", reply.major,
                                be32toh(msg.major));
-               ret = 0;
+               ret = -1;
                goto end;
        }
 
@@ -614,7 +619,7 @@ static int open_index(struct relay_viewer_stream *stream)
 {
        int ret;
        char fullpath[PATH_MAX];
-       struct lttng_packet_index_file_hdr hdr;
+       struct ctf_packet_index_file_hdr hdr;
 
        if (stream->tracefile_count > 0) {
                ret = snprintf(fullpath, sizeof(fullpath), "%s/" DEFAULT_INDEX_DIR "/%s_%"
@@ -649,13 +654,13 @@ static int open_index(struct relay_viewer_stream *stream)
                PERROR("Reading index header");
                goto error;
        }
-       if (strncmp(hdr.magic, INDEX_MAGIC, sizeof(hdr.magic)) != 0) {
+       if (be32toh(hdr.magic) != CTF_INDEX_MAGIC) {
                ERR("Invalid header magic");
                ret = -1;
                goto error;
        }
-       if (be32toh(hdr.index_major) != INDEX_MAJOR ||
-                       be32toh(hdr.index_minor) != INDEX_MINOR) {
+       if (be32toh(hdr.index_major) != CTF_INDEX_MAJOR ||
+                       be32toh(hdr.index_minor) != CTF_INDEX_MINOR) {
                ERR("Invalid header version");
                ret = -1;
                goto error;
@@ -698,6 +703,7 @@ int init_viewer_stream(struct relay_stream *stream, int seek_last)
                        LTTNG_VIEWER_NAME_MAX);
        viewer_stream->tracefile_count = stream->tracefile_count;
        viewer_stream->metadata_flag = stream->metadata_flag;
+       viewer_stream->tracefile_count_last = -1ULL;
        if (seek_last) {
                viewer_stream->tracefile_count_current =
                        stream->tracefile_count_current;
@@ -706,11 +712,11 @@ int init_viewer_stream(struct relay_stream *stream, int seek_last)
                        stream->oldest_tracefile_id;
        }
 
-       /*
-        * The deletion of this ctf_trace object is only done in a call RCU of the
-        * relay stream making it valid as long as we have the read side lock.
-        */
        viewer_stream->ctf_trace = stream->ctf_trace;
+       if (viewer_stream->metadata_flag) {
+               viewer_stream->ctf_trace->viewer_metadata_stream =
+                       viewer_stream;
+       }
        uatomic_inc(&viewer_stream->ctf_trace->refcount);
 
        lttng_ht_node_init_u64(&viewer_stream->stream_n, stream->stream_handle);
@@ -746,7 +752,7 @@ int init_viewer_stream(struct relay_stream *stream, int seek_last)
        if (seek_last && viewer_stream->index_read_fd > 0) {
                ret = lseek(viewer_stream->index_read_fd,
                                viewer_stream->total_index_received *
-                                       sizeof(struct lttng_packet_index),
+                                       sizeof(struct ctf_packet_index),
                                SEEK_CUR);
                if (ret < 0) {
                        goto error;
@@ -764,7 +770,7 @@ error:
 /*
  * Rotate a stream to the next tracefile.
  *
- * Returns 0 on success, a negative value on error.
+ * Returns 0 on success, 1 on EOF, a negative value on error.
  */
 static
 int rotate_viewer_stream(struct relay_viewer_stream *viewer_stream,
@@ -777,6 +783,15 @@ int rotate_viewer_stream(struct relay_viewer_stream *viewer_stream,
 
        tracefile_id = (viewer_stream->tracefile_count_current + 1) %
                viewer_stream->tracefile_count;
+       /*
+        * Detect the last tracefile to open.
+        */
+       if (viewer_stream->tracefile_count_last != -1ULL &&
+                       viewer_stream->tracefile_count_last ==
+                       viewer_stream->tracefile_count_current) {
+               ret = 1;
+               goto end;
+       }
 
        if (stream) {
                pthread_mutex_lock(&stream->viewer_stream_rotation_lock);
@@ -802,26 +817,22 @@ int rotate_viewer_stream(struct relay_viewer_stream *viewer_stream,
        }
        viewer_stream->tracefile_count_current = tracefile_id;
 
-       if (viewer_stream->abort_flag == 0) {
-               if (viewer_stream->index_read_fd > 0) {
-                       ret = close(viewer_stream->index_read_fd);
-                       if (ret < 0) {
-                               PERROR("close index file %d",
-                                               viewer_stream->index_read_fd);
-                       }
-                       viewer_stream->index_read_fd = -1;
-               }
-               if (viewer_stream->read_fd > 0) {
-                       ret = close(viewer_stream->read_fd);
-                       if (ret < 0) {
-                               PERROR("close tracefile %d",
-                                               viewer_stream->read_fd);
-                       }
-                       viewer_stream->read_fd = -1;
-               }
-       } else {
-               viewer_stream->abort_flag = 0;
+       ret = close(viewer_stream->index_read_fd);
+       if (ret < 0) {
+               PERROR("close index file %d",
+                               viewer_stream->index_read_fd);
        }
+       viewer_stream->index_read_fd = -1;
+       ret = close(viewer_stream->read_fd);
+       if (ret < 0) {
+               PERROR("close tracefile %d",
+                               viewer_stream->read_fd);
+       }
+       viewer_stream->read_fd = -1;
+
+       pthread_mutex_lock(&viewer_stream->overwrite_lock);
+       viewer_stream->abort_flag = 0;
+       pthread_mutex_unlock(&viewer_stream->overwrite_lock);
 
        viewer_stream->index_read_fd = -1;
        viewer_stream->read_fd = -1;
@@ -836,6 +847,7 @@ int rotate_viewer_stream(struct relay_viewer_stream *viewer_stream,
 
        ret = 0;
 
+end:
 error:
        return ret;
 }
@@ -847,7 +859,8 @@ static
 int viewer_attach_session(struct relay_command *cmd,
                struct lttng_ht *sessions_ht)
 {
-       int ret, send_streams = 0, nb_streams = 0;
+       int ret, send_streams = 0;
+       uint32_t nb_streams = 0, nb_streams_ready = 0;
        struct lttng_viewer_attach_session_request request;
        struct lttng_viewer_attach_session_response response;
        struct lttng_viewer_stream send_stream;
@@ -954,14 +967,16 @@ int viewer_attach_session(struct relay_command *cmd,
                        if (stream->session != cmd->session) {
                                continue;
                        }
+                       nb_streams++;
 
                        /*
-                        * Don't send streams with no ctf_trace, they are not ready to be
-                        * read.
+                        * Don't send streams with no ctf_trace, they are not
+                        * ready to be read.
                         */
-                       if (!stream->ctf_trace) {
+                       if (!stream->ctf_trace || !stream->viewer_ready) {
                                continue;
                        }
+                       nb_streams_ready++;
 
                        vstream = live_find_viewer_stream_by_id(stream->stream_handle);
                        if (!vstream) {
@@ -970,7 +985,11 @@ int viewer_attach_session(struct relay_command *cmd,
                                        goto end_unlock;
                                }
                        }
-                       nb_streams++;
+               }
+
+               /* We must have the same amount of existing stream and ready stream. */
+               if (nb_streams != nb_streams_ready) {
+                       nb_streams = 0;
                }
                response.streams_count = htobe32(nb_streams);
        }
@@ -985,10 +1004,10 @@ send_reply:
        health_code_update();
 
        /*
-        * Unknown or busy session, just return gracefully, the viewer knows what
+        * Unknown or empty session, just return gracefully, the viewer knows what
         * is happening.
         */
-       if (!send_streams) {
+       if (!send_streams || !nb_streams) {
                ret = 0;
                goto end_unlock;
        }
@@ -1056,6 +1075,107 @@ end:
        return stream;
 }
 
+static
+void deferred_free_viewer_stream(struct rcu_head *head)
+{
+       struct relay_viewer_stream *stream =
+               caa_container_of(head, struct relay_viewer_stream, rcu_node);
+
+       free(stream->path_name);
+       free(stream->channel_name);
+       free(stream);
+}
+
+static
+void delete_viewer_stream(struct relay_viewer_stream *vstream)
+{
+       int delret;
+       struct lttng_ht_iter iter;
+
+       iter.iter.node = &vstream->stream_n.node;
+       delret = lttng_ht_del(viewer_streams_ht, &iter);
+       assert(!delret);
+}
+
+static
+void destroy_viewer_stream(struct relay_viewer_stream *vstream)
+{
+       unsigned long ret_ref;
+       int ret;
+
+       assert(vstream);
+       ret_ref = uatomic_add_return(&vstream->ctf_trace->refcount, -1);
+       assert(ret_ref >= 0);
+
+       if (vstream->read_fd >= 0) {
+               ret = close(vstream->read_fd);
+               if (ret < 0) {
+                       PERROR("close read_fd");
+               }
+       }
+       if (vstream->index_read_fd >= 0) {
+               ret = close(vstream->index_read_fd);
+               if (ret < 0) {
+                       PERROR("close index_read_fd");
+               }
+       }
+
+       /*
+        * If the only stream left in the HT is the metadata stream,
+        * we need to remove it because we won't detect a EOF for this
+        * stream.
+        */
+       if (ret_ref == 1 && vstream->ctf_trace->viewer_metadata_stream) {
+               delete_viewer_stream(vstream->ctf_trace->viewer_metadata_stream);
+               destroy_viewer_stream(vstream->ctf_trace->viewer_metadata_stream);
+               vstream->ctf_trace->metadata_stream = NULL;
+               DBG("Freeing ctf_trace %" PRIu64, vstream->ctf_trace->id);
+               /*
+                * The streaming-side is already closed and we can't receive a new
+                * stream concurrently at this point (since the session is being
+                * destroyed), so when we detect the refcount equals 0, we are the
+                * only owners of the ctf_trace and we can free it ourself.
+                */
+               free(vstream->ctf_trace);
+       }
+
+       call_rcu(&vstream->rcu_node, deferred_free_viewer_stream);
+}
+
+/*
+ * Atomically check if new streams got added in the session since the last
+ * check and reset the flag to 0.
+ *
+ * Returns 1 if new streams got added, 0 if nothing changed, a negative value
+ * on error.
+ */
+static
+int check_new_streams(uint64_t session_id, struct lttng_ht *sessions_ht)
+{
+       struct lttng_ht_node_ulong *node;
+       struct lttng_ht_iter iter;
+       struct relay_session *session;
+       unsigned long current_val;
+       int ret;
+
+       lttng_ht_lookup(sessions_ht,
+                       (void *)((unsigned long) session_id), &iter);
+       node = lttng_ht_iter_get_node_ulong(&iter);
+       if (node == NULL) {
+               DBG("Relay session %" PRIu64 " not found", session_id);
+               ret = -1;
+               goto error;
+       }
+
+       session = caa_container_of(node, struct relay_session, session_n);
+
+       current_val = uatomic_cmpxchg(&session->new_streams, 1, 0);
+       ret = current_val;
+
+error:
+       return ret;
+}
+
 /*
  * Send the next index for a stream.
  *
@@ -1068,7 +1188,7 @@ int viewer_get_next_index(struct relay_command *cmd,
        int ret;
        struct lttng_viewer_get_next_index request_index;
        struct lttng_viewer_index viewer_index;
-       struct lttng_packet_index packet_index;
+       struct ctf_packet_index packet_index;
        struct relay_viewer_stream *vstream;
        struct relay_stream *rstream;
 
@@ -1134,6 +1254,11 @@ int viewer_get_next_index(struct relay_command *cmd,
                        ret = rotate_viewer_stream(vstream, rstream);
                        if (ret < 0) {
                                goto end_unlock;
+                       } else if (ret == 1) {
+                               viewer_index.status = htobe32(VIEWER_INDEX_HUP);
+                               delete_viewer_stream(vstream);
+                               destroy_viewer_stream(vstream);
+                               goto send_reply;
                        }
                }
                pthread_mutex_lock(&rstream->viewer_stream_rotation_lock);
@@ -1162,6 +1287,8 @@ int viewer_get_next_index(struct relay_command *cmd,
                        vstream->total_index_received == vstream->last_sent_index) {
                /* Last index sent and current tracefile closed in write */
                viewer_index.status = htobe32(VIEWER_INDEX_HUP);
+               delete_viewer_stream(vstream);
+               destroy_viewer_stream(vstream);
                goto send_reply;
        } else {
                vstream->close_write_flag = 1;
@@ -1173,6 +1300,13 @@ int viewer_get_next_index(struct relay_command *cmd,
                viewer_index.flags |= LTTNG_VIEWER_FLAG_NEW_METADATA;
        }
 
+       ret = check_new_streams(vstream->session_id, sessions_ht);
+       if (ret < 0) {
+               goto end_unlock;
+       } else if (ret == 1) {
+               viewer_index.flags |= LTTNG_VIEWER_FLAG_NEW_STREAM;
+       }
+
        pthread_mutex_lock(&vstream->overwrite_lock);
        if (vstream->abort_flag) {
                /*
@@ -1184,6 +1318,11 @@ int viewer_get_next_index(struct relay_command *cmd,
                ret = rotate_viewer_stream(vstream, rstream);
                if (ret < 0) {
                        goto end_unlock;
+               } else if (ret == 1) {
+                       viewer_index.status = htobe32(VIEWER_INDEX_HUP);
+                       delete_viewer_stream(vstream);
+                       destroy_viewer_stream(vstream);
+                       goto send_reply;
                }
                goto send_reply;
        }
@@ -1200,6 +1339,11 @@ int viewer_get_next_index(struct relay_command *cmd,
                        ret = rotate_viewer_stream(vstream, rstream);
                        if (ret < 0) {
                                goto end_unlock;
+                       } else if (ret == 1) {
+                               viewer_index.status = htobe32(VIEWER_INDEX_HUP);
+                               delete_viewer_stream(vstream);
+                               destroy_viewer_stream(vstream);
+                               goto send_reply;
                        }
                } else {
                        PERROR("Relay reading index file %d",
@@ -1251,7 +1395,8 @@ end:
  * Return 0 on success or else a negative value.
  */
 static
-int viewer_get_packet(struct relay_command *cmd)
+int viewer_get_packet(struct relay_command *cmd,
+               struct lttng_ht *sessions_ht)
 {
        int ret, send_data = 0;
        char *data = NULL;
@@ -1326,6 +1471,15 @@ int viewer_get_packet(struct relay_command *cmd)
                goto send_reply;
        }
 
+       ret = check_new_streams(stream->session_id, sessions_ht);
+       if (ret < 0) {
+               goto end_unlock;
+       } else if (ret == 1) {
+               reply.status = htobe32(VIEWER_GET_PACKET_ERR);
+               reply.flags |= LTTNG_VIEWER_FLAG_NEW_STREAM;
+               goto send_reply;
+       }
+
        len = be32toh(get_packet_info.len);
        data = zmalloc(len);
        if (!data) {
@@ -1560,7 +1714,7 @@ int process_control(struct lttng_viewer_cmd *recv_hdr,
                ret = viewer_get_next_index(cmd, sessions_ht);
                break;
        case VIEWER_GET_PACKET:
-               ret = viewer_get_packet(cmd);
+               ret = viewer_get_packet(cmd, sessions_ht);
                break;
        case VIEWER_GET_METADATA:
                ret = viewer_get_metadata(cmd);
@@ -1648,66 +1802,38 @@ void deferred_free_connection(struct rcu_head *head)
        free(relay_connection);
 }
 
-static
-void deferred_free_viewer_stream(struct rcu_head *head)
-{
-       struct relay_viewer_stream *stream =
-               caa_container_of(head, struct relay_viewer_stream, rcu_node);
-
-       if (stream->ctf_trace) {
-               uatomic_dec(&stream->ctf_trace->refcount);
-               assert(uatomic_read(&stream->ctf_trace->refcount) >= 0);
-               if (uatomic_read(&stream->ctf_trace->refcount) == 0) {
-                       DBG("Freeing ctf_trace %" PRIu64, stream->ctf_trace->id);
-                       free(stream->ctf_trace);
-               }
-       }
-
-       free(stream->path_name);
-       free(stream->channel_name);
-       free(stream);
-}
-
+/*
+ * Delete all streams for a specific session ID.
+ */
 static
 void viewer_del_streams(uint64_t session_id)
 {
-       int ret;
        struct relay_viewer_stream *stream;
-       struct lttng_ht_node_u64 *node;
        struct lttng_ht_iter iter;
 
        rcu_read_lock();
-       cds_lfht_for_each_entry(viewer_streams_ht->ht, &iter.iter, node, node) {
+       cds_lfht_for_each_entry(viewer_streams_ht->ht, &iter.iter, stream,
+                       stream_n.node) {
                health_code_update();
 
-               node = lttng_ht_iter_get_node_u64(&iter);
-               if (!node) {
-                       continue;
-               }
-
-               stream = caa_container_of(node, struct relay_viewer_stream, stream_n);
                if (stream->session_id != session_id) {
                        continue;
                }
 
-               if (stream->read_fd >= 0) {
-                       ret = close(stream->read_fd);
-                       if (ret < 0) {
-                               PERROR("close read_fd");
-                       }
-               }
-               if (stream->index_read_fd >= 0) {
-                       ret = close(stream->index_read_fd);
-                       if (ret < 0) {
-                               PERROR("close index_read_fd");
-                       }
-               }
-               if (stream->metadata_flag && stream->ctf_trace) {
+               delete_viewer_stream(stream);
+               assert(stream->ctf_trace);
+
+               if (stream->metadata_flag) {
+                       /*
+                        * The metadata viewer stream is destroyed once the refcount on the
+                        * ctf trace goes to 0 in the destroy stream function thus there is
+                        * no explicit call to that function here.
+                        */
                        stream->ctf_trace->metadata_sent = 0;
+                       stream->ctf_trace->viewer_metadata_stream = NULL;
+               } else {
+                       destroy_viewer_stream(stream);
                }
-               ret = lttng_ht_del(viewer_streams_ht, &iter);
-               assert(!ret);
-               call_rcu(&stream->rcu_node, deferred_free_viewer_stream);
        }
        rcu_read_unlock();
 }
@@ -1727,6 +1853,9 @@ void del_connection(struct lttng_ht *relay_connections_ht,
        assert(iter);
        assert(relay_connection);
 
+       DBG("Cleaning connection of session ID %" PRIu64,
+                       relay_connection->session_id);
+
        ret = lttng_ht_del(relay_connections_ht, iter);
        assert(!ret);
 
@@ -1758,6 +1887,10 @@ void *thread_worker(void *data)
 
        health_register(health_relayd, HEALTH_RELAYD_TYPE_LIVE_WORKER);
 
+       if (testpoint(relayd_thread_live_worker)) {
+               goto error_testpoint;
+       }
+
        /* table of connections indexed on socket */
        relay_connections_ht = lttng_ht_new(0, LTTNG_HT_TYPE_ULONG);
        if (!relay_connections_ht) {
@@ -1913,6 +2046,7 @@ relay_connections_ht_error:
                DBG("Viewer worker thread exited with error");
        }
        DBG("Viewer worker thread cleanup complete");
+error_testpoint:
        if (err) {
                health_error();
                ERR("Health error occurred in %s", __func__);
@@ -1971,7 +2105,7 @@ error:
  * main
  */
 int live_start_threads(struct lttng_uri *uri,
-               struct relay_local_data *relay_ctx, int quit_pipe[2])
+               struct relay_local_data *relay_ctx)
 {
        int ret = 0;
        void *status;
@@ -1980,9 +2114,6 @@ int live_start_threads(struct lttng_uri *uri,
        assert(uri);
        live_uri = uri;
 
-       live_thread_quit_pipe[0] = quit_pipe[0];
-       live_thread_quit_pipe[1] = quit_pipe[1];
-
        /* Check if daemon is UID = 0 */
        is_root = !getuid();
 
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