Fix: prevent calling adding the same trace recursively

[babeltrace.git] / formats / lttng-live / lttng-live-comm.c

diff --git a/formats/lttng-live/lttng-live-comm.c b/formats/lttng-live/lttng-live-comm.c
index 0c6228b463bdff63b974da617328105ee1945725..e08926380efab45e306a01ec59607012f51fbc90 100644 (file)
--- a/formats/lttng-live/lttng-live-comm.c
+++ b/formats/lttng-live/lttng-live-comm.c
@@ -390,6 +390,7 @@ int lttng_live_ctf_trace_assign(struct lttng_live_viewer_stream *stream,
        if (!trace) {
                trace = g_new0(struct lttng_live_ctf_trace, 1);
                trace->ctf_trace_id = ctf_trace_id;
+               printf_verbose("Create trace ctf_trace_id %" PRIu64 "\n", ctf_trace_id);
                BT_INIT_LIST_HEAD(&trace->stream_list);
                g_hash_table_insert(stream->session->ctf_traces,
                                &trace->ctf_trace_id,
@@ -844,6 +845,9 @@ int get_one_metadata_packet(struct lttng_live_ctx *ctx,
        memcpy(cmd_buf, &cmd, sizeof(cmd));
        memcpy(cmd_buf + sizeof(cmd), &rq, sizeof(rq));
 
+       printf_verbose("get_metadata for trace_id: %d, ctf_trace_id: %" PRIu64 "\n",
+                       metadata_stream->ctf_trace->trace_id,
+                       metadata_stream->ctf_trace->ctf_trace_id);
        ret_len = lttng_live_send(ctx->control_sock, cmd_buf, cmd_buf_len);
        if (ret_len < 0) {
                perror("[error] Error sending get_metadata cmd and request");
@@ -1104,6 +1108,7 @@ retry:
                bt_list_del(&viewer_stream->trace_stream_node);
                bt_list_del(&viewer_stream->session_stream_node);
                g_free(viewer_stream);
+               *stream_id = be64toh(rp->stream_id);
                break;
        case LTTNG_VIEWER_INDEX_ERR:
                fprintf(stderr, "[error] get_next_index: error\n");
@@ -1477,6 +1482,9 @@ int add_one_trace(struct lttng_live_ctx *ctx,
        struct bt_trace_descriptor *td;
        struct bt_trace_handle *handle;
 
+       printf_verbose("Add one trace ctf_trace_id: %" PRIu64
+                       " (metadata_stream: %p)\n",
+                       trace->ctf_trace_id, trace->metadata_stream);
        /*
         * We don't know how many streams we will receive for a trace, so
         * once we are done receiving the traces, we add all the traces
@@ -1487,9 +1495,16 @@ int add_one_trace(struct lttng_live_ctx *ctx,
         * If a trace is already in the context, we just skip this function.
         */
        if (trace->in_use) {
+               printf_verbose("Trace already in use\n");
                ret = 0;
                goto end;
        }
+       /*
+        * add_one_trace can be called recursively if during the
+        * bt_context_add_trace call we need to fetch new streams, so we need to
+        * prevent a recursive call to process our current trace.
+        */
+       trace->in_use = 1;
 
        BT_INIT_LIST_HEAD(&mmap_list.head);
 
@@ -1515,6 +1530,7 @@ int add_one_trace(struct lttng_live_ctx *ctx,
                                goto end_free;
                        }
 
+                       printf_verbose("Metadata stream found\n");
                        trace->metadata_fp = babeltrace_fmemopen(metadata_buf,
                                        stream->metadata_len, "rb");
                        if (!trace->metadata_fp) {
@@ -1551,7 +1567,7 @@ int add_one_trace(struct lttng_live_ctx *ctx,
        }
 
        trace->trace_id = ret;
-       trace->in_use = 1;
+       printf_verbose("Trace now in use, id = %d\n", trace->trace_id);
 
        goto end;
 
@@ -1561,6 +1577,56 @@ end:
        return ret;
 }
 
+/*
+ * Make sure all the traces we know have a metadata stream or loop on
+ * ask_new_streams until it is done. This must be called before we call
+ * add_one_trace.
+ *
+ * Return 0 when all known traces have a metadata stream, a negative value
+ * on error.
+ */
+static
+int check_traces_metadata(struct lttng_live_ctx *ctx)
+{
+       int ret;
+       struct lttng_live_ctf_trace *trace;
+       GHashTableIter it;
+       gpointer key;
+       gpointer value;
+
+retry:
+       g_hash_table_iter_init(&it, ctx->session->ctf_traces);
+       while (g_hash_table_iter_next(&it, &key, &value)) {
+               trace = (struct lttng_live_ctf_trace *) value;
+               printf_verbose("Check trace %" PRIu64 " metadata\n", trace->ctf_trace_id);
+               while (!trace->metadata_stream) {
+                       printf_verbose("Waiting for metadata stream\n");
+                       if (lttng_live_should_quit()) {
+                               ret = 0;
+                               goto end;
+                       }
+                       ret = ask_new_streams(ctx);
+                       if (ret < 0) {
+                               goto end;
+                       } else if (ret == 0) {
+                               (void) poll(NULL, 0, ACTIVE_POLL_DELAY);
+                       } else {
+                               /*
+                                * If ask_new_stream got streams from a trace we did not know
+                                * about until now, we have to reinitialize the iterator.
+                                */
+                               goto retry;
+                       }
+               }
+       }
+
+       ret = 0;
+
+end:
+       printf_verbose("End check traces metadata\n");
+       return ret;
+}
+
 static
 int add_traces(struct lttng_live_ctx *ctx)
 {
@@ -1569,6 +1635,17 @@ int add_traces(struct lttng_live_ctx *ctx)
        GHashTableIter it;
        gpointer key;
        gpointer value;
+       unsigned int nr_traces;
+
+       printf_verbose("Begin add traces\n");
+
+retry:
+       nr_traces = g_hash_table_size(ctx->session->ctf_traces);
+
+       ret = check_traces_metadata(ctx);
+       if (ret < 0) {
+               goto end;
+       }
 
        g_hash_table_iter_init(&it, ctx->session->ctf_traces);
        while (g_hash_table_iter_next(&it, &key, &value)) {
@@ -1577,11 +1654,21 @@ int add_traces(struct lttng_live_ctx *ctx)
                if (ret < 0) {
                        goto end;
                }
+               /*
+                * If a new trace got added while we were adding the trace, the
+                * iterator is invalid and we have to restart.
+                */
+               if (g_hash_table_size(ctx->session->ctf_traces) != nr_traces) {
+                       printf_verbose("New trace(s) added during add_one_trace()\n");
+                       printf_verbose("JORAJ: GREP HERE\n");
+                       goto retry;
+               }
        }
 
        ret = 0;
 
 end:
+       printf_verbose("End add traces\n");
        return ret;
 }