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         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,
  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         session->ctf_traces_ht = lttng_ht_new(0, LTTNG_HT_TYPE_STRING);
 119         if (!session->ctf_traces_ht) {
 120                 goto error;
 121         }
 122
 123         pthread_mutex_lock(&last_relay_session_id_lock);
 124         session->id = ++last_relay_session_id;
 125         pthread_mutex_unlock(&last_relay_session_id_lock);
 126
 127         session->major = major;
 128         session->minor = minor;
 129         lttng_ht_node_init_u64(&session->session_n, session->id);
 130         urcu_ref_init(&session->ref);
 131         CDS_INIT_LIST_HEAD(&session->recv_list);
 132         pthread_mutex_init(&session->lock, NULL);
 133         pthread_mutex_init(&session->recv_list_lock, NULL);
 134
 135         session->live_timer = live_timer;
 136         session->snapshot = snapshot;
 137         lttng_uuid_copy(session->sessiond_uuid, sessiond_uuid);
 138
 139         if (id_sessiond) {
 140                 LTTNG_OPTIONAL_SET(&session->id_sessiond, *id_sessiond);
 141         }
 142
 143         ret = sessiond_trace_chunk_registry_session_created(
 144                         sessiond_trace_chunk_registry, sessiond_uuid);
 145         if (ret) {
 146                 goto error;
 147         }
 148
 149         if (id_sessiond && current_chunk_id) {
 150                 session->current_trace_chunk =
 151                                 sessiond_trace_chunk_registry_get_chunk(
 152                                         sessiond_trace_chunk_registry,
 153                                         session->sessiond_uuid,
 154                                         session->id_sessiond.value,
 155                                         *current_chunk_id);
 156                 if (!session->current_trace_chunk) {
 157                         char uuid_str[UUID_STR_LEN];
 158
 159                         lttng_uuid_to_str(sessiond_uuid, uuid_str);
 160                         ERR("Could not find trace chunk: sessiond = {%s}, sessiond session id = %" PRIu64 ", trace chunk id = %" PRIu64,
 161                                         uuid_str, *id_sessiond,
 162                                         *current_chunk_id);
 163                 }
 164         } else if (!id_sessiond) {
 165                 /*
 166                  * Pre-2.11 peers will not announce trace chunks. An
 167                  * anonymous trace chunk which will remain set for the
 168                  * duration of the session is created.
 169                  */
 170                 ret = session_set_anonymous_chunk(session);
 171                 if (ret) {
 172                         goto error;
 173                 }
 174         }
 175
 176         lttng_ht_add_unique_u64(sessions_ht, &session->session_n);
 177         if (creation_time) {
 178                 LTTNG_OPTIONAL_SET(&session->creation_time, *creation_time);
 179         }
 180         return session;
 181
 182 error:
 183         session_put(session);
 184         return NULL;
 185 }
 186
 187 /* Should be called with RCU read-side lock held. */
 188 bool session_get(struct relay_session *session)
 189 {
 190         return urcu_ref_get_unless_zero(&session->ref);
 191 }
 192
 193 /*
 194  * Lookup a session within the session hash table using the session id
 195  * as key. A session reference is taken when a session is returned.
 196  * session_put() must be called on that session.
 197  *
 198  * Return session or NULL if not found.
 199  */
 200 struct relay_session *session_get_by_id(uint64_t id)
 201 {
 202         struct relay_session *session = NULL;
 203         struct lttng_ht_node_u64 *node;
 204         struct lttng_ht_iter iter;
 205
 206         rcu_read_lock();
 207         lttng_ht_lookup(sessions_ht, &id, &iter);
 208         node = lttng_ht_iter_get_node_u64(&iter);
 209         if (!node) {
 210                 DBG("Session find by ID %" PRIu64 " id NOT found", id);
 211                 goto end;
 212         }
 213         session = caa_container_of(node, struct relay_session, session_n);
 214         DBG("Session find by ID %" PRIu64 " id found", id);
 215         if (!session_get(session)) {
 216                 session = NULL;
 217         }
 218 end:
 219         rcu_read_unlock();
 220         return session;
 221 }
 222
 223 static void rcu_destroy_session(struct rcu_head *rcu_head)
 224 {
 225         struct relay_session *session =
 226                         caa_container_of(rcu_head, struct relay_session,
 227                                 rcu_node);
 228         /*
 229          * Since each trace has a reference on the session, it means
 230          * that if we are at the point where we teardown the session, no
 231          * trace belonging to that session exist at this point.
 232          * Calling lttng_ht_destroy in call_rcu worker thread so we
 233          * don't hold the RCU read-side lock while calling it.
 234          */
 235         lttng_ht_destroy(session->ctf_traces_ht);
 236         free(session);
 237 }
 238
 239 /*
 240  * Delete session from the given hash table.
 241  *
 242  * Return lttng ht del error code being 0 on success and 1 on failure.
 243  */
 244 static int session_delete(struct relay_session *session)
 245 {
 246         struct lttng_ht_iter iter;
 247
 248         iter.iter.node = &session->session_n.node;
 249         return lttng_ht_del(sessions_ht, &iter);
 250 }
 251
 252
 253 static void destroy_session(struct relay_session *session)
 254 {
 255         int ret;
 256
 257         ret = session_delete(session);
 258         assert(!ret);
 259         lttng_trace_chunk_put(session->current_trace_chunk);
 260         session->current_trace_chunk = NULL;
 261         lttng_trace_chunk_put(session->pending_closure_trace_chunk);
 262         session->pending_closure_trace_chunk = NULL;
 263         ret = sessiond_trace_chunk_registry_session_destroyed(
 264                         sessiond_trace_chunk_registry, session->sessiond_uuid);
 265         assert(!ret);
 266         call_rcu(&session->rcu_node, rcu_destroy_session);
 267 }
 268
 269 void session_release(struct urcu_ref *ref)
 270 {
 271         struct relay_session *session =
 272                         caa_container_of(ref, struct relay_session, ref);
 273
 274         destroy_session(session);
 275 }
 276
 277 void session_put(struct relay_session *session)
 278 {
 279         rcu_read_lock();
 280         urcu_ref_put(&session->ref, session_release);
 281         rcu_read_unlock();
 282 }
 283
 284 int session_close(struct relay_session *session)
 285 {
 286         int ret = 0;
 287         struct ctf_trace *trace;
 288         struct lttng_ht_iter iter;
 289         struct relay_stream *stream;
 290
 291         pthread_mutex_lock(&session->lock);
 292         DBG("closing session %" PRIu64 ": is conn already closed %d",
 293                         session->id, session->connection_closed);
 294         session->connection_closed = true;
 295         pthread_mutex_unlock(&session->lock);
 296
 297         rcu_read_lock();
 298         cds_lfht_for_each_entry(session->ctf_traces_ht->ht,
 299                         &iter.iter, trace, node.node) {
 300                 ret = ctf_trace_close(trace);
 301                 if (ret) {
 302                         goto rcu_unlock;
 303                 }
 304         }
 305         cds_list_for_each_entry_rcu(stream, &session->recv_list,
 306                         recv_node) {
 307                 /* Close streams which have not been published yet. */
 308                 try_stream_close(stream);
 309         }
 310 rcu_unlock:
 311         rcu_read_unlock();
 312         if (ret) {
 313                 return ret;
 314         }
 315         /* Put self-reference from create. */
 316         session_put(session);
 317         return ret;
 318 }
 319
 320 int session_abort(struct relay_session *session)
 321 {
 322         int ret = 0;
 323
 324         if (!session) {
 325                 return 0;
 326         }
 327
 328         pthread_mutex_lock(&session->lock);
 329         DBG("aborting session %" PRIu64, session->id);
 330         session->aborted = true;
 331         pthread_mutex_unlock(&session->lock);
 332         return ret;
 333 }
 334
 335 void print_sessions(void)
 336 {
 337         struct lttng_ht_iter iter;
 338         struct relay_session *session;
 339
 340         if (!sessions_ht) {
 341                 return;
 342         }
 343
 344         rcu_read_lock();
 345         cds_lfht_for_each_entry(sessions_ht->ht, &iter.iter, session,
 346                         session_n.node) {
 347                 if (!session_get(session)) {
 348                         continue;
 349                 }
 350                 DBG("session %p refcount %ld session %" PRIu64,
 351                         session,
 352                         session->ref.refcount,
 353                         session->id);
 354                 session_put(session);
 355         }
 356         rcu_read_unlock();
 357 }