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 <common/compat/uuid.h>
  23 #include <urcu/rculist.h>
  24
  25 #include "lttng-relayd.h"
  26 #include "ctf-trace.h"
  27 #include "session.h"
  28 #include "stream.h"
  29 #include "sessiond-trace-chunks.h"
  30
  31 /* Global session id used in the session creation. */
  32 static uint64_t last_relay_session_id;
  33 static pthread_mutex_t last_relay_session_id_lock = PTHREAD_MUTEX_INITIALIZER;
  34
  35 static int session_set_anonymous_chunk(struct relay_session *session)
  36 {
  37         int ret = 0;
  38         struct lttng_trace_chunk *chunk = NULL;
  39         enum lttng_trace_chunk_status status;
  40         struct lttng_directory_handle output_directory;
  41
  42         ret = lttng_directory_handle_init(&output_directory, opt_output_path);
  43         if (ret) {
  44                 goto end;
  45         }
  46
  47         chunk = lttng_trace_chunk_create_anonymous();
  48         if (!chunk) {
  49                 goto end;
  50         }
  51
  52         status = lttng_trace_chunk_set_credentials_current_user(chunk);
  53         if (status != LTTNG_TRACE_CHUNK_STATUS_OK) {
  54                 ret = -1;
  55                 goto end;
  56         }
  57
  58         status = lttng_trace_chunk_set_as_owner(chunk, &output_directory);
  59         if (status != LTTNG_TRACE_CHUNK_STATUS_OK) {
  60                 ret = -1;
  61                 goto end;
  62         }
  63         session->current_trace_chunk = chunk;
  64         chunk = NULL;
  65 end:
  66         lttng_trace_chunk_put(chunk);
  67         lttng_directory_handle_fini(&output_directory);
  68         return ret;
  69 }
  70
  71 /*
  72  * Create a new session by assigning a new session ID.
  73  *
  74  * Return allocated session or else NULL.
  75  */
  76 struct relay_session *session_create(const char *session_name,
  77                 const char *hostname, uint32_t live_timer,
  78                 bool snapshot, const lttng_uuid sessiond_uuid,
  79                 uint64_t *id_sessiond, uint64_t *current_chunk_id,
  80                 uint32_t major, uint32_t minor)
  81 {
  82         int ret;
  83         struct relay_session *session;
  84
  85         session = zmalloc(sizeof(*session));
  86         if (!session) {
  87                 PERROR("Failed to allocate session");
  88                 goto error;
  89         }
  90         if (lttng_strncpy(session->session_name, session_name,
  91                         sizeof(session->session_name))) {
  92                 WARN("Session name exceeds maximal allowed length");
  93                 goto error;
  94         }
  95         if (lttng_strncpy(session->hostname, hostname,
  96                         sizeof(session->hostname))) {
  97                 WARN("Hostname exceeds maximal allowed length");
  98                 goto error;
  99         }
 100         session->ctf_traces_ht = lttng_ht_new(0, LTTNG_HT_TYPE_STRING);
 101         if (!session->ctf_traces_ht) {
 102                 goto error;
 103         }
 104
 105         pthread_mutex_lock(&last_relay_session_id_lock);
 106         session->id = ++last_relay_session_id;
 107         pthread_mutex_unlock(&last_relay_session_id_lock);
 108
 109         session->major = major;
 110         session->minor = minor;
 111         lttng_ht_node_init_u64(&session->session_n, session->id);
 112         urcu_ref_init(&session->ref);
 113         CDS_INIT_LIST_HEAD(&session->recv_list);
 114         pthread_mutex_init(&session->lock, NULL);
 115         pthread_mutex_init(&session->recv_list_lock, NULL);
 116
 117         session->live_timer = live_timer;
 118         session->snapshot = snapshot;
 119         lttng_uuid_copy(session->sessiond_uuid, sessiond_uuid);
 120
 121         if (id_sessiond) {
 122                 LTTNG_OPTIONAL_SET(&session->id_sessiond, *id_sessiond);
 123         }
 124
 125         ret = sessiond_trace_chunk_registry_session_created(
 126                         sessiond_trace_chunk_registry, sessiond_uuid);
 127         if (ret) {
 128                 goto error;
 129         }
 130
 131         if (id_sessiond && current_chunk_id) {
 132                 session->current_trace_chunk =
 133                                 sessiond_trace_chunk_registry_get_chunk(
 134                                         sessiond_trace_chunk_registry,
 135                                         session->sessiond_uuid,
 136                                         session->id_sessiond.value,
 137                                         *current_chunk_id);
 138                 if (!session->current_trace_chunk) {
 139                         char uuid_str[UUID_STR_LEN];
 140
 141                         lttng_uuid_to_str(sessiond_uuid, uuid_str);
 142                         ERR("Could not find trace chunk: sessiond = {%s}, sessiond session id = %" PRIu64 ", trace chunk id = %" PRIu64,
 143                                         uuid_str, *id_sessiond,
 144                                         *current_chunk_id);
 145                 }
 146         } else if (!id_sessiond) {
 147                 /*
 148                  * Pre-2.11 peers will not announce trace chunks. An
 149                  * anonymous trace chunk which will remain set for the
 150                  * duration of the session is created.
 151                  */
 152                 ret = session_set_anonymous_chunk(session);
 153                 if (ret) {
 154                         goto error;
 155                 }
 156         }
 157
 158         lttng_ht_add_unique_u64(sessions_ht, &session->session_n);
 159         return session;
 160
 161 error:
 162         session_put(session);
 163         return NULL;
 164 }
 165
 166 /* Should be called with RCU read-side lock held. */
 167 bool session_get(struct relay_session *session)
 168 {
 169         return urcu_ref_get_unless_zero(&session->ref);
 170 }
 171
 172 /*
 173  * Lookup a session within the session hash table using the session id
 174  * as key. A session reference is taken when a session is returned.
 175  * session_put() must be called on that session.
 176  *
 177  * Return session or NULL if not found.
 178  */
 179 struct relay_session *session_get_by_id(uint64_t id)
 180 {
 181         struct relay_session *session = NULL;
 182         struct lttng_ht_node_u64 *node;
 183         struct lttng_ht_iter iter;
 184
 185         rcu_read_lock();
 186         lttng_ht_lookup(sessions_ht, &id, &iter);
 187         node = lttng_ht_iter_get_node_u64(&iter);
 188         if (!node) {
 189                 DBG("Session find by ID %" PRIu64 " id NOT found", id);
 190                 goto end;
 191         }
 192         session = caa_container_of(node, struct relay_session, session_n);
 193         DBG("Session find by ID %" PRIu64 " id found", id);
 194         if (!session_get(session)) {
 195                 session = NULL;
 196         }
 197 end:
 198         rcu_read_unlock();
 199         return session;
 200 }
 201
 202 static void rcu_destroy_session(struct rcu_head *rcu_head)
 203 {
 204         struct relay_session *session =
 205                         caa_container_of(rcu_head, struct relay_session,
 206                                 rcu_node);
 207         /*
 208          * Since each trace has a reference on the session, it means
 209          * that if we are at the point where we teardown the session, no
 210          * trace belonging to that session exist at this point.
 211          * Calling lttng_ht_destroy in call_rcu worker thread so we
 212          * don't hold the RCU read-side lock while calling it.
 213          */
 214         lttng_ht_destroy(session->ctf_traces_ht);
 215         free(session);
 216 }
 217
 218 /*
 219  * Delete session from the given hash table.
 220  *
 221  * Return lttng ht del error code being 0 on success and 1 on failure.
 222  */
 223 static int session_delete(struct relay_session *session)
 224 {
 225         struct lttng_ht_iter iter;
 226
 227         iter.iter.node = &session->session_n.node;
 228         return lttng_ht_del(sessions_ht, &iter);
 229 }
 230
 231
 232 static void destroy_session(struct relay_session *session)
 233 {
 234         int ret;
 235
 236         ret = session_delete(session);
 237         assert(!ret);
 238         lttng_trace_chunk_put(session->current_trace_chunk);
 239         ret = sessiond_trace_chunk_registry_session_destroyed(
 240                         sessiond_trace_chunk_registry, session->sessiond_uuid);
 241         assert(!ret);
 242         lttng_trace_chunk_put(session->current_trace_chunk);
 243         session->current_trace_chunk = NULL;
 244         call_rcu(&session->rcu_node, rcu_destroy_session);
 245 }
 246
 247 void session_release(struct urcu_ref *ref)
 248 {
 249         struct relay_session *session =
 250                         caa_container_of(ref, struct relay_session, ref);
 251
 252         destroy_session(session);
 253 }
 254
 255 void session_put(struct relay_session *session)
 256 {
 257         rcu_read_lock();
 258         urcu_ref_put(&session->ref, session_release);
 259         rcu_read_unlock();
 260 }
 261
 262 int session_close(struct relay_session *session)
 263 {
 264         int ret = 0;
 265         struct ctf_trace *trace;
 266         struct lttng_ht_iter iter;
 267         struct relay_stream *stream;
 268
 269         pthread_mutex_lock(&session->lock);
 270         DBG("closing session %" PRIu64 ": is conn already closed %d",
 271                         session->id, session->connection_closed);
 272         session->connection_closed = true;
 273         pthread_mutex_unlock(&session->lock);
 274
 275         rcu_read_lock();
 276         cds_lfht_for_each_entry(session->ctf_traces_ht->ht,
 277                         &iter.iter, trace, node.node) {
 278                 ret = ctf_trace_close(trace);
 279                 if (ret) {
 280                         goto rcu_unlock;
 281                 }
 282         }
 283         cds_list_for_each_entry_rcu(stream, &session->recv_list,
 284                         recv_node) {
 285                 /* Close streams which have not been published yet. */
 286                 try_stream_close(stream);
 287         }
 288 rcu_unlock:
 289         rcu_read_unlock();
 290         if (ret) {
 291                 return ret;
 292         }
 293         /* Put self-reference from create. */
 294         session_put(session);
 295         return ret;
 296 }
 297
 298 int session_abort(struct relay_session *session)
 299 {
 300         int ret = 0;
 301
 302         if (!session) {
 303                 return 0;
 304         }
 305
 306         pthread_mutex_lock(&session->lock);
 307         DBG("aborting session %" PRIu64, session->id);
 308         session->aborted = true;
 309         pthread_mutex_unlock(&session->lock);
 310         return ret;
 311 }
 312
 313 void print_sessions(void)
 314 {
 315         struct lttng_ht_iter iter;
 316         struct relay_session *session;
 317
 318         if (!sessions_ht) {
 319                 return;
 320         }
 321
 322         rcu_read_lock();
 323         cds_lfht_for_each_entry(sessions_ht->ht, &iter.iter, session,
 324                         session_n.node) {
 325                 if (!session_get(session)) {
 326                         continue;
 327                 }
 328                 DBG("session %p refcount %ld session %" PRIu64,
 329                         session,
 330                         session->ref.refcount,
 331                         session->id);
 332                 session_put(session);
 333         }
 334         rcu_read_unlock();
 335 }