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/utils.h>
  23 #include <common/compat/uuid.h>
  24 #include <urcu/rculist.h>
  25
  26 #include "ctf-trace.h"
  27 #include "lttng-relayd.h"
  28 #include "session.h"
  29 #include "sessiond-trace-chunks.h"
  30 #include "stream.h"
  31
  32 /* Global session id used in the session creation. */
  33 static uint64_t last_relay_session_id;
  34 static pthread_mutex_t last_relay_session_id_lock = PTHREAD_MUTEX_INITIALIZER;
  35
  36 static int session_set_anonymous_chunk(struct relay_session *session)
  37 {
  38         int ret = 0;
  39         struct lttng_trace_chunk *chunk = NULL;
  40         enum lttng_trace_chunk_status status;
  41         struct lttng_directory_handle output_directory;
  42         const char *base_path = opt_output_path;
  43
  44         if (base_path == NULL) {
  45                 /* No output path defined */
  46                 base_path = utils_get_home_dir();
  47                 if (base_path == NULL) {
  48                         ERR("Home path not found.\n \
  49                                         Please specify an output path using -o, --output PATH");
  50                         ret = -1;
  51                         goto end;
  52                 }
  53         }
  54
  55         ret = lttng_directory_handle_init(&output_directory, base_path);
  56         if (ret) {
  57                 goto end;
  58         }
  59
  60         chunk = lttng_trace_chunk_create_anonymous();
  61         if (!chunk) {
  62                 goto end;
  63         }
  64
  65         status = lttng_trace_chunk_set_credentials_current_user(chunk);
  66         if (status != LTTNG_TRACE_CHUNK_STATUS_OK) {
  67                 ret = -1;
  68                 goto end;
  69         }
  70
  71         status = lttng_trace_chunk_set_as_owner(chunk, &output_directory);
  72         if (status != LTTNG_TRACE_CHUNK_STATUS_OK) {
  73                 ret = -1;
  74                 goto end;
  75         }
  76         session->current_trace_chunk = chunk;
  77         chunk = NULL;
  78 end:
  79         lttng_trace_chunk_put(chunk);
  80         lttng_directory_handle_fini(&output_directory);
  81         return ret;
  82 }
  83
  84 /*
  85  * Create a new session by assigning a new session ID.
  86  *
  87  * Return allocated session or else NULL.
  88  */
  89 struct relay_session *session_create(const char *session_name,
  90                 const char *hostname, const char *base_path,
  91                 uint32_t live_timer,
  92                 bool snapshot,
  93                 const lttng_uuid sessiond_uuid,
  94                 const uint64_t *id_sessiond,
  95                 const uint64_t *current_chunk_id,
  96                 const time_t *creation_time,
  97                 uint32_t major,
  98                 uint32_t minor)
  99 {
 100         int ret;
 101         struct relay_session *session;
 102
 103         session = zmalloc(sizeof(*session));
 104         if (!session) {
 105                 PERROR("Failed to allocate session");
 106                 goto error;
 107         }
 108         if (lttng_strncpy(session->session_name, session_name,
 109                         sizeof(session->session_name))) {
 110                 WARN("Session name exceeds maximal allowed length");
 111                 goto error;
 112         }
 113         if (lttng_strncpy(session->hostname, hostname,
 114                         sizeof(session->hostname))) {
 115                 WARN("Hostname exceeds maximal allowed length");
 116                 goto error;
 117         }
 118         if (lttng_strncpy(session->base_path, base_path,
 119                         sizeof(session->base_path))) {
 120                 WARN("Base path exceeds maximal allowed length");
 121                 goto error;
 122         }
 123
 124         session->ctf_traces_ht = lttng_ht_new(0, LTTNG_HT_TYPE_STRING);
 125         if (!session->ctf_traces_ht) {
 126                 goto error;
 127         }
 128
 129         pthread_mutex_lock(&last_relay_session_id_lock);
 130         session->id = ++last_relay_session_id;
 131         pthread_mutex_unlock(&last_relay_session_id_lock);
 132
 133         session->major = major;
 134         session->minor = minor;
 135         lttng_ht_node_init_u64(&session->session_n, session->id);
 136         urcu_ref_init(&session->ref);
 137         CDS_INIT_LIST_HEAD(&session->recv_list);
 138         pthread_mutex_init(&session->lock, NULL);
 139         pthread_mutex_init(&session->recv_list_lock, NULL);
 140
 141         session->live_timer = live_timer;
 142         session->snapshot = snapshot;
 143         lttng_uuid_copy(session->sessiond_uuid, sessiond_uuid);
 144
 145         if (id_sessiond) {
 146                 LTTNG_OPTIONAL_SET(&session->id_sessiond, *id_sessiond);
 147         }
 148
 149         ret = sessiond_trace_chunk_registry_session_created(
 150                         sessiond_trace_chunk_registry, sessiond_uuid);
 151         if (ret) {
 152                 goto error;
 153         }
 154
 155         if (id_sessiond && current_chunk_id) {
 156                 session->current_trace_chunk =
 157                                 sessiond_trace_chunk_registry_get_chunk(
 158                                         sessiond_trace_chunk_registry,
 159                                         session->sessiond_uuid,
 160                                         session->id_sessiond.value,
 161                                         *current_chunk_id);
 162                 if (!session->current_trace_chunk) {
 163                         char uuid_str[UUID_STR_LEN];
 164
 165                         lttng_uuid_to_str(sessiond_uuid, uuid_str);
 166                         ERR("Could not find trace chunk: sessiond = {%s}, sessiond session id = %" PRIu64 ", trace chunk id = %" PRIu64,
 167                                         uuid_str, *id_sessiond,
 168                                         *current_chunk_id);
 169                 }
 170         } else if (!id_sessiond) {
 171                 /*
 172                  * Pre-2.11 peers will not announce trace chunks. An
 173                  * anonymous trace chunk which will remain set for the
 174                  * duration of the session is created.
 175                  */
 176                 ret = session_set_anonymous_chunk(session);
 177                 if (ret) {
 178                         goto error;
 179                 }
 180         }
 181
 182         lttng_ht_add_unique_u64(sessions_ht, &session->session_n);
 183         if (creation_time) {
 184                 LTTNG_OPTIONAL_SET(&session->creation_time, *creation_time);
 185         }
 186         return session;
 187
 188 error:
 189         session_put(session);
 190         return NULL;
 191 }
 192
 193 /* Should be called with RCU read-side lock held. */
 194 bool session_get(struct relay_session *session)
 195 {
 196         return urcu_ref_get_unless_zero(&session->ref);
 197 }
 198
 199 /*
 200  * Lookup a session within the session hash table using the session id
 201  * as key. A session reference is taken when a session is returned.
 202  * session_put() must be called on that session.
 203  *
 204  * Return session or NULL if not found.
 205  */
 206 struct relay_session *session_get_by_id(uint64_t id)
 207 {
 208         struct relay_session *session = NULL;
 209         struct lttng_ht_node_u64 *node;
 210         struct lttng_ht_iter iter;
 211
 212         rcu_read_lock();
 213         lttng_ht_lookup(sessions_ht, &id, &iter);
 214         node = lttng_ht_iter_get_node_u64(&iter);
 215         if (!node) {
 216                 DBG("Session find by ID %" PRIu64 " id NOT found", id);
 217                 goto end;
 218         }
 219         session = caa_container_of(node, struct relay_session, session_n);
 220         DBG("Session find by ID %" PRIu64 " id found", id);
 221         if (!session_get(session)) {
 222                 session = NULL;
 223         }
 224 end:
 225         rcu_read_unlock();
 226         return session;
 227 }
 228
 229 static void rcu_destroy_session(struct rcu_head *rcu_head)
 230 {
 231         struct relay_session *session =
 232                         caa_container_of(rcu_head, struct relay_session,
 233                                 rcu_node);
 234         /*
 235          * Since each trace has a reference on the session, it means
 236          * that if we are at the point where we teardown the session, no
 237          * trace belonging to that session exist at this point.
 238          * Calling lttng_ht_destroy in call_rcu worker thread so we
 239          * don't hold the RCU read-side lock while calling it.
 240          */
 241         lttng_ht_destroy(session->ctf_traces_ht);
 242         free(session);
 243 }
 244
 245 /*
 246  * Delete session from the given hash table.
 247  *
 248  * Return lttng ht del error code being 0 on success and 1 on failure.
 249  */
 250 static int session_delete(struct relay_session *session)
 251 {
 252         struct lttng_ht_iter iter;
 253
 254         iter.iter.node = &session->session_n.node;
 255         return lttng_ht_del(sessions_ht, &iter);
 256 }
 257
 258
 259 static void destroy_session(struct relay_session *session)
 260 {
 261         int ret;
 262
 263         ret = session_delete(session);
 264         assert(!ret);
 265         lttng_trace_chunk_put(session->current_trace_chunk);
 266         session->current_trace_chunk = NULL;
 267         lttng_trace_chunk_put(session->pending_closure_trace_chunk);
 268         session->pending_closure_trace_chunk = NULL;
 269         ret = sessiond_trace_chunk_registry_session_destroyed(
 270                         sessiond_trace_chunk_registry, session->sessiond_uuid);
 271         assert(!ret);
 272         call_rcu(&session->rcu_node, rcu_destroy_session);
 273 }
 274
 275 void session_release(struct urcu_ref *ref)
 276 {
 277         struct relay_session *session =
 278                         caa_container_of(ref, struct relay_session, ref);
 279
 280         destroy_session(session);
 281 }
 282
 283 void session_put(struct relay_session *session)
 284 {
 285         rcu_read_lock();
 286         urcu_ref_put(&session->ref, session_release);
 287         rcu_read_unlock();
 288 }
 289
 290 int session_close(struct relay_session *session)
 291 {
 292         int ret = 0;
 293         struct ctf_trace *trace;
 294         struct lttng_ht_iter iter;
 295         struct relay_stream *stream;
 296
 297         pthread_mutex_lock(&session->lock);
 298         DBG("closing session %" PRIu64 ": is conn already closed %d",
 299                         session->id, session->connection_closed);
 300         session->connection_closed = true;
 301         pthread_mutex_unlock(&session->lock);
 302
 303         rcu_read_lock();
 304         cds_lfht_for_each_entry(session->ctf_traces_ht->ht,
 305                         &iter.iter, trace, node.node) {
 306                 ret = ctf_trace_close(trace);
 307                 if (ret) {
 308                         goto rcu_unlock;
 309                 }
 310         }
 311         cds_list_for_each_entry_rcu(stream, &session->recv_list,
 312                         recv_node) {
 313                 /* Close streams which have not been published yet. */
 314                 try_stream_close(stream);
 315         }
 316 rcu_unlock:
 317         rcu_read_unlock();
 318         if (ret) {
 319                 return ret;
 320         }
 321         /* Put self-reference from create. */
 322         session_put(session);
 323         return ret;
 324 }
 325
 326 int session_abort(struct relay_session *session)
 327 {
 328         int ret = 0;
 329
 330         if (!session) {
 331                 return 0;
 332         }
 333
 334         pthread_mutex_lock(&session->lock);
 335         DBG("aborting session %" PRIu64, session->id);
 336         session->aborted = true;
 337         pthread_mutex_unlock(&session->lock);
 338         return ret;
 339 }
 340
 341 void print_sessions(void)
 342 {
 343         struct lttng_ht_iter iter;
 344         struct relay_session *session;
 345
 346         if (!sessions_ht) {
 347                 return;
 348         }
 349
 350         rcu_read_lock();
 351         cds_lfht_for_each_entry(sessions_ht->ht, &iter.iter, session,
 352                         session_n.node) {
 353                 if (!session_get(session)) {
 354                         continue;
 355                 }
 356                 DBG("session %p refcount %ld session %" PRIu64,
 357                         session,
 358                         session->ref.refcount,
 359                         session->id);
 360                 session_put(session);
 361         }
 362         rcu_read_unlock();
 363 }