Fix: relay_recv_metadata does not check for partial write
[lttng-tools.git] / src / bin / lttng-relayd / session.c
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1/*
2 * Copyright (C) 2013 - Julien Desfossez <jdesfossez@efficios.com>
3 * David Goulet <dgoulet@efficios.com>
7591bab1 4 * 2015 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
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5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License, version 2 only, as
8 * published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
13 * more details.
14 *
15 * You should have received a copy of the GNU General Public License along with
16 * this program; if not, write to the Free Software Foundation, Inc., 51
17 * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
18 */
19
6c1c0768 20#define _LGPL_SOURCE
2a174661 21#include <common/common.h>
7591bab1 22#include <urcu/rculist.h>
2a174661 23
7591bab1 24#include "lttng-relayd.h"
2a174661 25#include "ctf-trace.h"
2f8f53af 26#include "session.h"
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27#include "stream.h"
28
29/* Global session id used in the session creation. */
30static uint64_t last_relay_session_id;
7591bab1 31static pthread_mutex_t last_relay_session_id_lock = PTHREAD_MUTEX_INITIALIZER;
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32
33/*
34 * Create a new session by assigning a new session ID.
35 *
36 * Return allocated session or else NULL.
37 */
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38struct relay_session *session_create(const char *session_name,
39 const char *hostname, uint32_t live_timer,
40 bool snapshot, uint32_t major, uint32_t minor)
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41{
42 struct relay_session *session;
43
44 session = zmalloc(sizeof(*session));
45 if (!session) {
46 PERROR("relay session zmalloc");
47 goto error;
48 }
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49 if (lttng_strncpy(session->session_name, session_name,
50 sizeof(session->session_name))) {
51 goto error;
52 }
53 if (lttng_strncpy(session->hostname, hostname,
54 sizeof(session->hostname))) {
55 goto error;
56 }
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57 session->ctf_traces_ht = lttng_ht_new(0, LTTNG_HT_TYPE_STRING);
58 if (!session->ctf_traces_ht) {
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59 goto error;
60 }
61
7591bab1 62 pthread_mutex_lock(&last_relay_session_id_lock);
2a174661 63 session->id = ++last_relay_session_id;
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64 pthread_mutex_unlock(&last_relay_session_id_lock);
65
66 session->major = major;
67 session->minor = minor;
2a174661 68 lttng_ht_node_init_u64(&session->session_n, session->id);
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69 urcu_ref_init(&session->ref);
70 CDS_INIT_LIST_HEAD(&session->recv_list);
71 pthread_mutex_init(&session->lock, NULL);
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72 pthread_mutex_init(&session->recv_list_lock, NULL);
73
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74 session->live_timer = live_timer;
75 session->snapshot = snapshot;
76
77 lttng_ht_add_unique_u64(sessions_ht, &session->session_n);
bb5d54e7 78 return session;
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79
80error:
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81 free(session);
82 return NULL;
2a174661 83}
2f8f53af 84
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85/* Should be called with RCU read-side lock held. */
86bool session_get(struct relay_session *session)
87{
ce4d4083 88 return urcu_ref_get_unless_zero(&session->ref);
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89}
90
2f8f53af 91/*
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92 * Lookup a session within the session hash table using the session id
93 * as key. A session reference is taken when a session is returned.
94 * session_put() must be called on that session.
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95 *
96 * Return session or NULL if not found.
97 */
7591bab1 98struct relay_session *session_get_by_id(uint64_t id)
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99{
100 struct relay_session *session = NULL;
2a174661 101 struct lttng_ht_node_u64 *node;
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102 struct lttng_ht_iter iter;
103
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104 rcu_read_lock();
105 lttng_ht_lookup(sessions_ht, &id, &iter);
2a174661 106 node = lttng_ht_iter_get_node_u64(&iter);
2f8f53af 107 if (!node) {
2a174661 108 DBG("Session find by ID %" PRIu64 " id NOT found", id);
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109 goto end;
110 }
111 session = caa_container_of(node, struct relay_session, session_n);
2a174661 112 DBG("Session find by ID %" PRIu64 " id found", id);
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113 if (!session_get(session)) {
114 session = NULL;
115 }
2f8f53af 116end:
7591bab1 117 rcu_read_unlock();
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118 return session;
119}
2a174661 120
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121static void rcu_destroy_session(struct rcu_head *rcu_head)
122{
123 struct relay_session *session =
124 caa_container_of(rcu_head, struct relay_session,
125 rcu_node);
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126 /*
127 * Since each trace has a reference on the session, it means
128 * that if we are at the point where we teardown the session, no
129 * trace belonging to that session exist at this point.
130 * Calling lttng_ht_destroy in call_rcu worker thread so we
131 * don't hold the RCU read-side lock while calling it.
132 */
133 lttng_ht_destroy(session->ctf_traces_ht);
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134 free(session);
135}
136
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137/*
138 * Delete session from the given hash table.
139 *
140 * Return lttng ht del error code being 0 on success and 1 on failure.
141 */
7591bab1 142static int session_delete(struct relay_session *session)
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143{
144 struct lttng_ht_iter iter;
145
2a174661 146 iter.iter.node = &session->session_n.node;
7591bab1 147 return lttng_ht_del(sessions_ht, &iter);
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148}
149
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150
151static void destroy_session(struct relay_session *session)
152{
153 int ret;
154
155 ret = session_delete(session);
156 assert(!ret);
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157 call_rcu(&session->rcu_node, rcu_destroy_session);
158}
159
160void session_release(struct urcu_ref *ref)
2a174661 161{
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162 struct relay_session *session =
163 caa_container_of(ref, struct relay_session, ref);
2a174661 164
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165 destroy_session(session);
166}
2a174661 167
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168void session_put(struct relay_session *session)
169{
170 rcu_read_lock();
7591bab1 171 urcu_ref_put(&session->ref, session_release);
7591bab1 172 rcu_read_unlock();
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173}
174
7591bab1 175int session_close(struct relay_session *session)
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176{
177 int ret = 0;
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178 struct ctf_trace *trace;
179 struct lttng_ht_iter iter;
180 struct relay_stream *stream;
181
182 pthread_mutex_lock(&session->lock);
183 DBG("closing session %" PRIu64 ": is conn already closed %d",
184 session->id, session->connection_closed);
185 if (session->connection_closed) {
186 ret = -1;
187 goto unlock;
188 }
189 session->connection_closed = true;
190unlock:
191 pthread_mutex_unlock(&session->lock);
192 if (ret) {
193 return ret;
194 }
2a174661 195
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196 rcu_read_lock();
197 cds_lfht_for_each_entry(session->ctf_traces_ht->ht,
198 &iter.iter, trace, node.node) {
199 ret = ctf_trace_close(trace);
200 if (ret) {
201 goto rcu_unlock;
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202 }
203 }
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204 cds_list_for_each_entry_rcu(stream, &session->recv_list,
205 recv_node) {
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206 /* Close streams which have not been published yet. */
207 try_stream_close(stream);
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208 }
209rcu_unlock:
210 rcu_read_unlock();
211 if (ret) {
212 return ret;
213 }
214 /* Put self-reference from create. */
215 session_put(session);
216 return ret;
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217}
218
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219int session_abort(struct relay_session *session)
220{
221 int ret = 0;
222
223 if (!session) {
224 return 0;
225 }
226
227 pthread_mutex_lock(&session->lock);
228 DBG("aborting session %" PRIu64, session->id);
229 if (session->aborted) {
230 ERR("session %" PRIu64 " is already aborted", session->id);
231 ret = -1;
232 goto unlock;
233 }
234 session->aborted = true;
235unlock:
236 pthread_mutex_unlock(&session->lock);
237 return ret;
238}
239
7591bab1 240void print_sessions(void)
2a174661 241{
2a174661 242 struct lttng_ht_iter iter;
7591bab1 243 struct relay_session *session;
2a174661 244
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245 if (!sessions_ht) {
246 return;
247 }
248
2a174661 249 rcu_read_lock();
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250 cds_lfht_for_each_entry(sessions_ht->ht, &iter.iter, session,
251 session_n.node) {
252 if (!session_get(session)) {
253 continue;
254 }
255 DBG("session %p refcount %ld session %" PRIu64,
256 session,
257 session->ref.refcount,
258 session->id);
259 session_put(session);
2a174661 260 }
2a174661 261 rcu_read_unlock();
2a174661 262}
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