2 * Copyright (C) 2013 Julien Desfossez <jdesfossez@efficios.com>
3 * Copyright (C) 2013 David Goulet <dgoulet@efficios.com>
4 * Copyright (C) 2015 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
6 * SPDX-License-Identifier: GPL-2.0-only
12 #include "ctf-trace.hpp"
13 #include "lttng-relayd.hpp"
16 #include <common/common.hpp>
17 #include <common/urcu.hpp>
18 #include <common/utils.hpp>
20 #include <urcu/rculist.h>
22 static uint64_t last_relay_ctf_trace_id
;
23 static pthread_mutex_t last_relay_ctf_trace_id_lock
= PTHREAD_MUTEX_INITIALIZER
;
25 static void rcu_destroy_ctf_trace(struct rcu_head
*rcu_head
)
27 struct ctf_trace
*trace
= lttng::utils::container_of(rcu_head
, &ctf_trace::rcu_node
);
33 * Destroy a ctf trace and all stream contained in it.
35 * MUST be called with the RCU read side lock.
37 static void ctf_trace_destroy(struct ctf_trace
*trace
)
40 * Getting to this point, every stream referenced by that trace
41 * have put back their ref since the've been closed by the
44 LTTNG_ASSERT(cds_list_empty(&trace
->stream_list
));
45 ASSERT_RCU_READ_LOCKED();
47 session_put(trace
->session
);
48 trace
->session
= nullptr;
50 trace
->path
= nullptr;
51 call_rcu(&trace
->rcu_node
, rcu_destroy_ctf_trace
);
54 static void ctf_trace_release(struct urcu_ref
*ref
)
56 struct ctf_trace
*trace
= lttng::utils::container_of(ref
, &ctf_trace::ref
);
58 struct lttng_ht_iter iter
;
60 iter
.iter
.node
= &trace
->node
.node
;
61 ret
= lttng_ht_del(trace
->session
->ctf_traces_ht
, &iter
);
63 ctf_trace_destroy(trace
);
67 * The caller must either:
68 * - hold the RCU read side lock, or
69 * - guarantee the existence of the object by already holding a reference to
72 bool ctf_trace_get(struct ctf_trace
*trace
)
74 const bool ref
= urcu_ref_get_unless_zero(&trace
->ref
);
78 * The ref count is already zero. It means the object is being
79 * torn down concurently.
80 * This is only acceptable if we hold the RCU read-side lock,
81 * else it's a logic error.
83 ASSERT_RCU_READ_LOCKED();
90 * Create and return an allocated ctf_trace. NULL on error.
91 * There is no "open" and "close" for a ctf_trace, but rather just a
92 * create and refcounting. Whenever all the streams belonging to a trace
93 * put their reference, its refcount drops to 0.
95 static struct ctf_trace
*ctf_trace_create(struct relay_session
*session
, const char *subpath
)
97 struct ctf_trace
*trace
;
99 trace
= zmalloc
<ctf_trace
>();
101 PERROR("Failed to allocate ctf_trace");
104 urcu_ref_init(&trace
->ref
);
106 if (!session_get(session
)) {
107 ERR("Failed to acquire session reference");
110 trace
->session
= session
;
111 trace
->path
= strdup(subpath
);
116 CDS_INIT_LIST_HEAD(&trace
->stream_list
);
118 pthread_mutex_lock(&last_relay_ctf_trace_id_lock
);
119 trace
->id
= ++last_relay_ctf_trace_id
;
120 pthread_mutex_unlock(&last_relay_ctf_trace_id_lock
);
122 lttng_ht_node_init_str(&trace
->node
, trace
->path
);
123 trace
->session
= session
;
124 pthread_mutex_init(&trace
->lock
, nullptr);
125 pthread_mutex_init(&trace
->stream_list_lock
, nullptr);
126 lttng_ht_add_str(session
->ctf_traces_ht
, &trace
->node
);
128 DBG("Created ctf_trace %" PRIu64
" of session \"%s\" from host \"%s\" with path: %s",
130 session
->session_name
,
137 ctf_trace_put(trace
);
142 * Return a ctf_trace if found by id in the given hash table else NULL.
143 * Hold a reference on the ctf_trace, and must be paired with
146 struct ctf_trace
*ctf_trace_get_by_path_or_create(struct relay_session
*session
,
149 struct lttng_ht_node_str
*node
;
150 struct lttng_ht_iter iter
;
151 struct ctf_trace
*trace
= nullptr;
153 lttng::urcu::read_lock_guard read_lock
;
154 lttng_ht_lookup(session
->ctf_traces_ht
, subpath
, &iter
);
155 node
= lttng_ht_iter_get_node
<lttng_ht_node_str
>(&iter
);
157 DBG("CTF Trace path %s not found", subpath
);
160 trace
= lttng::utils::container_of(node
, &ctf_trace::node
);
161 if (!ctf_trace_get(trace
)) {
167 trace
= ctf_trace_create(session
, subpath
);
172 void ctf_trace_put(struct ctf_trace
*trace
)
174 lttng::urcu::read_lock_guard read_lock
;
175 urcu_ref_put(&trace
->ref
, ctf_trace_release
);
178 int ctf_trace_close(struct ctf_trace
*trace
)
180 struct relay_stream
*stream
;
182 lttng::urcu::read_lock_guard read_lock
;
183 cds_list_for_each_entry_rcu(stream
, &trace
->stream_list
, stream_node
)
186 * Close stream since the connection owning the trace is being
189 try_stream_close(stream
);
192 * Since all references to the trace are held by its streams, we
193 * don't need to do any self-ref put.
198 struct relay_viewer_stream
*ctf_trace_get_viewer_metadata_stream(struct ctf_trace
*trace
)
200 struct relay_viewer_stream
*vstream
;
202 lttng::urcu::read_lock_guard read_lock
;
203 vstream
= rcu_dereference(trace
->viewer_metadata_stream
);
207 if (!viewer_stream_get(vstream
)) {