src/bin/lttng-relayd/session.c

   1 /*
   2  * Copyright (C) 2013 - Julien Desfossez <jdesfossez@efficios.com>
   3  *                      David Goulet <dgoulet@efficios.com>
   4  *               2015 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   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
  20 #define _LGPL_SOURCE
  21 #include <common/common.h>
  22 #include <urcu/rculist.h>
  23
  24 #include "lttng-relayd.h"
  25 #include "ctf-trace.h"
  26 #include "session.h"
  27 #include "stream.h"
  28
  29 /* Global session id used in the session creation. */
  30 static uint64_t last_relay_session_id;
  31 static pthread_mutex_t last_relay_session_id_lock = PTHREAD_MUTEX_INITIALIZER;
  32
  33 /*
  34  * Create a new session by assigning a new session ID.
  35  *
  36  * Return allocated session or else NULL.
  37  */
  38 struct 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)
  41 {
  42         struct relay_session *session;
  43
  44         session = zmalloc(sizeof(*session));
  45         if (!session) {
  46                 PERROR("relay session zmalloc");
  47                 goto error;
  48         }
  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         }
  57         fprintf(stderr, "hostname; %s\n", hostname);
  58         session->ctf_traces_ht = lttng_ht_new(0, LTTNG_HT_TYPE_STRING);
  59         if (!session->ctf_traces_ht) {
  60                 goto error;
  61         }
  62
  63         pthread_mutex_lock(&last_relay_session_id_lock);
  64         session->id = ++last_relay_session_id;
  65         pthread_mutex_unlock(&last_relay_session_id_lock);
  66
  67         session->major = major;
  68         session->minor = minor;
  69         lttng_ht_node_init_u64(&session->session_n, session->id);
  70         urcu_ref_init(&session->ref);
  71         CDS_INIT_LIST_HEAD(&session->recv_list);
  72         pthread_mutex_init(&session->lock, NULL);
  73         pthread_mutex_init(&session->recv_list_lock, NULL);
  74
  75         session->live_timer = live_timer;
  76         session->snapshot = snapshot;
  77
  78         lttng_ht_add_unique_u64(sessions_ht, &session->session_n);
  79         return session;
  80
  81 error:
  82         free(session);
  83         return NULL;
  84 }
  85
  86 /* Should be called with RCU read-side lock held. */
  87 bool session_get(struct relay_session *session)
  88 {
  89         return urcu_ref_get_unless_zero(&session->ref);
  90 }
  91
  92 /*
  93  * Lookup a session within the session hash table using the session id
  94  * as key. A session reference is taken when a session is returned.
  95  * session_put() must be called on that session.
  96  *
  97  * Return session or NULL if not found.
  98  */
  99 struct relay_session *session_get_by_id(uint64_t id)
 100 {
 101         struct relay_session *session = NULL;
 102         struct lttng_ht_node_u64 *node;
 103         struct lttng_ht_iter iter;
 104
 105         rcu_read_lock();
 106         lttng_ht_lookup(sessions_ht, &id, &iter);
 107         node = lttng_ht_iter_get_node_u64(&iter);
 108         if (!node) {
 109                 DBG("Session find by ID %" PRIu64 " id NOT found", id);
 110                 goto end;
 111         }
 112         session = caa_container_of(node, struct relay_session, session_n);
 113         DBG("Session find by ID %" PRIu64 " id found", id);
 114         if (!session_get(session)) {
 115                 session = NULL;
 116         }
 117 end:
 118         rcu_read_unlock();
 119         return session;
 120 }
 121
 122 static void rcu_destroy_session(struct rcu_head *rcu_head)
 123 {
 124         struct relay_session *session =
 125                         caa_container_of(rcu_head, struct relay_session,
 126                                 rcu_node);
 127         /*
 128          * Since each trace has a reference on the session, it means
 129          * that if we are at the point where we teardown the session, no
 130          * trace belonging to that session exist at this point.
 131          * Calling lttng_ht_destroy in call_rcu worker thread so we
 132          * don't hold the RCU read-side lock while calling it.
 133          */
 134         lttng_ht_destroy(session->ctf_traces_ht);
 135         free(session);
 136 }
 137
 138 /*
 139  * Delete session from the given hash table.
 140  *
 141  * Return lttng ht del error code being 0 on success and 1 on failure.
 142  */
 143 static int session_delete(struct relay_session *session)
 144 {
 145         struct lttng_ht_iter iter;
 146
 147         iter.iter.node = &session->session_n.node;
 148         return lttng_ht_del(sessions_ht, &iter);
 149 }
 150
 151
 152 static void destroy_session(struct relay_session *session)
 153 {
 154         int ret;
 155
 156         ret = session_delete(session);
 157         assert(!ret);
 158         call_rcu(&session->rcu_node, rcu_destroy_session);
 159 }
 160
 161 void session_release(struct urcu_ref *ref)
 162 {
 163         struct relay_session *session =
 164                         caa_container_of(ref, struct relay_session, ref);
 165
 166         destroy_session(session);
 167 }
 168
 169 void session_put(struct relay_session *session)
 170 {
 171         rcu_read_lock();
 172         urcu_ref_put(&session->ref, session_release);
 173         rcu_read_unlock();
 174 }
 175
 176 int session_close(struct relay_session *session)
 177 {
 178         int ret = 0;
 179         struct ctf_trace *trace;
 180         struct lttng_ht_iter iter;
 181         struct relay_stream *stream;
 182
 183         pthread_mutex_lock(&session->lock);
 184         DBG("closing session %" PRIu64 ": is conn already closed %d",
 185                         session->id, session->connection_closed);
 186         if (session->connection_closed) {
 187                 ret = -1;
 188                 goto unlock;
 189         }
 190         session->connection_closed = true;
 191 unlock:
 192         pthread_mutex_unlock(&session->lock);
 193         if (ret) {
 194                 return ret;
 195         }
 196
 197         rcu_read_lock();
 198         cds_lfht_for_each_entry(session->ctf_traces_ht->ht,
 199                         &iter.iter, trace, node.node) {
 200                 ret = ctf_trace_close(trace);
 201                 if (ret) {
 202                         goto rcu_unlock;
 203                 }
 204         }
 205         cds_list_for_each_entry_rcu(stream, &session->recv_list,
 206                         recv_node) {
 207                 /* Close streams which have not been published yet. */
 208                 try_stream_close(stream);
 209         }
 210 rcu_unlock:
 211         rcu_read_unlock();
 212         if (ret) {
 213                 return ret;
 214         }
 215         /* Put self-reference from create. */
 216         session_put(session);
 217         return ret;
 218 }
 219
 220 int session_abort(struct relay_session *session)
 221 {
 222         int ret = 0;
 223
 224         if (!session) {
 225                 return 0;
 226         }
 227
 228         pthread_mutex_lock(&session->lock);
 229         DBG("aborting session %" PRIu64, session->id);
 230         if (session->aborted) {
 231                 ERR("session %" PRIu64 " is already aborted", session->id);
 232                 ret = -1;
 233                 goto unlock;
 234         }
 235         session->aborted = true;
 236 unlock:
 237         pthread_mutex_unlock(&session->lock);
 238         return ret;
 239 }
 240
 241 void print_sessions(void)
 242 {
 243         struct lttng_ht_iter iter;
 244         struct relay_session *session;
 245
 246         if (!sessions_ht) {
 247                 return;
 248         }
 249
 250         rcu_read_lock();
 251         cds_lfht_for_each_entry(sessions_ht->ht, &iter.iter, session,
 252                         session_n.node) {
 253                 if (!session_get(session)) {
 254                         continue;
 255                 }
 256                 DBG("session %p refcount %ld session %" PRIu64,
 257                         session,
 258                         session->ref.refcount,
 259                         session->id);
 260                 session_put(session);
 261         }
 262         rcu_read_unlock();
 263 }