bin: compile lttng-relayd as a C++

[lttng-tools.git] / src / bin / lttng-relayd / ctf-trace.cpp

diff --git a/src/bin/lttng-relayd/ctf-trace.cpp b/src/bin/lttng-relayd/ctf-trace.cpp
new file mode 100644 (file)
index 0000000..7a3cbde
--- /dev/null
+++ b/src/bin/lttng-relayd/ctf-trace.cpp
@@ -0,0 +1,198 @@
+/*
+ * Copyright (C) 2013 Julien Desfossez <jdesfossez@efficios.com>
+ * Copyright (C) 2013 David Goulet <dgoulet@efficios.com>
+ * Copyright (C) 2015 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0-only
+ *
+ */
+
+#define _LGPL_SOURCE
+
+#include <common/common.h>
+#include <common/utils.h>
+#include <urcu/rculist.h>
+
+#include "ctf-trace.h"
+#include "lttng-relayd.h"
+#include "stream.h"
+
+static uint64_t last_relay_ctf_trace_id;
+static pthread_mutex_t last_relay_ctf_trace_id_lock = PTHREAD_MUTEX_INITIALIZER;
+
+static void rcu_destroy_ctf_trace(struct rcu_head *rcu_head)
+{
+       struct ctf_trace *trace =
+               caa_container_of(rcu_head, struct ctf_trace, rcu_node);
+
+       free(trace);
+}
+
+/*
+ * Destroy a ctf trace and all stream contained in it.
+ *
+ * MUST be called with the RCU read side lock.
+ */
+static void ctf_trace_destroy(struct ctf_trace *trace)
+{
+       /*
+        * Getting to this point, every stream referenced by that trace
+        * have put back their ref since the've been closed by the
+        * control side.
+        */
+       LTTNG_ASSERT(cds_list_empty(&trace->stream_list));
+       session_put(trace->session);
+       trace->session = NULL;
+       free(trace->path);
+       trace->path = NULL;
+       call_rcu(&trace->rcu_node, rcu_destroy_ctf_trace);
+}
+
+static void ctf_trace_release(struct urcu_ref *ref)
+{
+       struct ctf_trace *trace =
+               caa_container_of(ref, struct ctf_trace, ref);
+       int ret;
+       struct lttng_ht_iter iter;
+
+       iter.iter.node = &trace->node.node;
+       ret = lttng_ht_del(trace->session->ctf_traces_ht, &iter);
+       LTTNG_ASSERT(!ret);
+       ctf_trace_destroy(trace);
+}
+
+/*
+ * Should be called with RCU read-side lock held.
+ */
+bool ctf_trace_get(struct ctf_trace *trace)
+{
+       return urcu_ref_get_unless_zero(&trace->ref);
+}
+
+/*
+ * Create and return an allocated ctf_trace. NULL on error.
+ * There is no "open" and "close" for a ctf_trace, but rather just a
+ * create and refcounting. Whenever all the streams belonging to a trace
+ * put their reference, its refcount drops to 0.
+ */
+static struct ctf_trace *ctf_trace_create(struct relay_session *session,
+               const char *subpath)
+{
+       struct ctf_trace *trace;
+
+       trace = (ctf_trace *) zmalloc(sizeof(*trace));
+       if (!trace) {
+               PERROR("Failed to allocate ctf_trace");
+               goto end;
+       }
+       urcu_ref_init(&trace->ref);
+
+       if (!session_get(session)) {
+               ERR("Failed to acquire session reference");
+               goto error;
+       }
+       trace->session = session;
+       trace->path = strdup(subpath);
+       if (!trace->path) {
+               goto error;
+       }
+
+       CDS_INIT_LIST_HEAD(&trace->stream_list);
+
+       pthread_mutex_lock(&last_relay_ctf_trace_id_lock);
+       trace->id = ++last_relay_ctf_trace_id;
+       pthread_mutex_unlock(&last_relay_ctf_trace_id_lock);
+
+       lttng_ht_node_init_str(&trace->node, trace->path);
+       trace->session = session;
+       pthread_mutex_init(&trace->lock, NULL);
+       pthread_mutex_init(&trace->stream_list_lock, NULL);
+       lttng_ht_add_str(session->ctf_traces_ht, &trace->node);
+
+       DBG("Created ctf_trace %" PRIu64 "of session \"%s\" from host \"%s\" with path: %s",
+                       trace->id, session->session_name, session->hostname,
+                       subpath);
+
+end:
+       return trace;
+error:
+       ctf_trace_put(trace);
+       return NULL;
+}
+
+/*
+ * Return a ctf_trace if found by id in the given hash table else NULL.
+ * Hold a reference on the ctf_trace, and must be paired with
+ * ctf_trace_put().
+ */
+struct ctf_trace *ctf_trace_get_by_path_or_create(struct relay_session *session,
+               const char *subpath)
+{
+       struct lttng_ht_node_str *node;
+       struct lttng_ht_iter iter;
+       struct ctf_trace *trace = NULL;
+
+       rcu_read_lock();
+       lttng_ht_lookup(session->ctf_traces_ht, subpath, &iter);
+       node = lttng_ht_iter_get_node_str(&iter);
+       if (!node) {
+               DBG("CTF Trace path %s not found", subpath);
+               goto end;
+       }
+       trace = caa_container_of(node, struct ctf_trace, node);
+       if (!ctf_trace_get(trace)) {
+               trace = NULL;
+       }
+end:
+       rcu_read_unlock();
+       if (!trace) {
+               /* Try to create */
+               trace = ctf_trace_create(session, subpath);
+       }
+       return trace;
+}
+
+void ctf_trace_put(struct ctf_trace *trace)
+{
+       rcu_read_lock();
+       urcu_ref_put(&trace->ref, ctf_trace_release);
+       rcu_read_unlock();
+}
+
+int ctf_trace_close(struct ctf_trace *trace)
+{
+       struct relay_stream *stream;
+
+       rcu_read_lock();
+       cds_list_for_each_entry_rcu(stream, &trace->stream_list,
+                       stream_node) {
+               /*
+                * Close stream since the connection owning the trace is being
+                * torn down.
+                */
+               try_stream_close(stream);
+       }
+       rcu_read_unlock();
+       /*
+        * Since all references to the trace are held by its streams, we
+        * don't need to do any self-ref put.
+        */
+       return 0;
+}
+
+struct relay_viewer_stream *ctf_trace_get_viewer_metadata_stream(struct ctf_trace *trace)
+{
+       struct relay_viewer_stream *vstream;
+
+       rcu_read_lock();
+       vstream = rcu_dereference(trace->viewer_metadata_stream);
+       if (!vstream) {
+               goto end;
+       }
+       if (!viewer_stream_get(vstream)) {
+               vstream = NULL;
+       }
+end:
+       rcu_read_unlock();
+       return vstream;
+}