src/bin/lttng-relayd/stream.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/defaults.h>
  24 #include <urcu/rculist.h>
  25 #include <sys/stat.h>
  26
  27 #include "lttng-relayd.h"
  28 #include "index.h"
  29 #include "stream.h"
  30 #include "viewer-stream.h"
  31
  32 /* Should be called with RCU read-side lock held. */
  33 bool stream_get(struct relay_stream *stream)
  34 {
  35         bool has_ref = false;
  36
  37         pthread_mutex_lock(&stream->reflock);
  38         if (stream->ref.refcount != 0) {
  39                 has_ref = true;
  40                 urcu_ref_get(&stream->ref);
  41         }
  42         pthread_mutex_unlock(&stream->reflock);
  43
  44         return has_ref;
  45 }
  46
  47 /*
  48  * Get stream from stream id from the streams hash table. Return stream
  49  * if found else NULL. A stream reference is taken when a stream is
  50  * returned. stream_put() must be called on that stream.
  51  */
  52 struct relay_stream *stream_get_by_id(uint64_t stream_id)
  53 {
  54         struct lttng_ht_node_u64 *node;
  55         struct lttng_ht_iter iter;
  56         struct relay_stream *stream = NULL;
  57
  58         rcu_read_lock();
  59         lttng_ht_lookup(relay_streams_ht, &stream_id, &iter);
  60         node = lttng_ht_iter_get_node_u64(&iter);
  61         if (!node) {
  62                 DBG("Relay stream %" PRIu64 " not found", stream_id);
  63                 goto end;
  64         }
  65         stream = caa_container_of(node, struct relay_stream, node);
  66         if (!stream_get(stream)) {
  67                 stream = NULL;
  68         }
  69 end:
  70         rcu_read_unlock();
  71         return stream;
  72 }
  73
  74 /*
  75  * We keep ownership of path_name and channel_name.
  76  */
  77 struct relay_stream *stream_create(struct ctf_trace *trace,
  78         uint64_t stream_handle, char *path_name,
  79         char *channel_name, uint64_t tracefile_size,
  80         uint64_t tracefile_count)
  81 {
  82         int ret;
  83         struct relay_stream *stream = NULL;
  84         struct relay_session *session = trace->session;
  85
  86         stream = zmalloc(sizeof(struct relay_stream));
  87         if (stream == NULL) {
  88                 PERROR("relay stream zmalloc");
  89                 goto error_no_alloc;
  90         }
  91
  92         stream->stream_handle = stream_handle;
  93         stream->prev_seq = -1ULL;
  94         stream->last_net_seq_num = -1ULL;
  95         stream->ctf_stream_id = -1ULL;
  96         stream->tracefile_size = tracefile_size;
  97         stream->tracefile_count = tracefile_count;
  98         stream->path_name = path_name;
  99         stream->channel_name = channel_name;
 100         lttng_ht_node_init_u64(&stream->node, stream->stream_handle);
 101         pthread_mutex_init(&stream->lock, NULL);
 102         pthread_mutex_init(&stream->reflock, NULL);
 103         urcu_ref_init(&stream->ref);
 104         ctf_trace_get(trace);
 105         stream->trace = trace;
 106
 107         stream->indexes_ht = lttng_ht_new(0, LTTNG_HT_TYPE_U64);
 108         if (!stream->indexes_ht) {
 109                 ERR("Cannot created indexes_ht");
 110                 ret = -1;
 111                 goto end;
 112         }
 113
 114         ret = utils_mkdir_recursive(stream->path_name, S_IRWXU | S_IRWXG,
 115                         -1, -1);
 116         if (ret < 0) {
 117                 ERR("relay creating output directory");
 118                 goto end;
 119         }
 120
 121         /*
 122          * No need to use run_as API here because whatever we receive,
 123          * the relayd uses its own credentials for the stream files.
 124          */
 125         ret = utils_create_stream_file(stream->path_name, stream->channel_name,
 126                         stream->tracefile_size, 0, -1, -1, NULL);
 127         if (ret < 0) {
 128                 ERR("Create output file");
 129                 goto end;
 130         }
 131         stream->stream_fd = stream_fd_create(ret);
 132         if (!stream->stream_fd) {
 133                 if (close(ret)) {
 134                         PERROR("Error closing file %d", ret);
 135                 }
 136                 ret = -1;
 137                 goto end;
 138         }
 139         stream->tfa = tracefile_array_create(stream->tracefile_count);
 140         if (!stream->tfa) {
 141                 ret = -1;
 142                 goto end;
 143         }
 144         if (stream->tracefile_size) {
 145                 DBG("Tracefile %s/%s_0 created", stream->path_name, stream->channel_name);
 146         } else {
 147                 DBG("Tracefile %s/%s created", stream->path_name, stream->channel_name);
 148         }
 149
 150         if (!strncmp(stream->channel_name, DEFAULT_METADATA_NAME, LTTNG_NAME_MAX)) {
 151                 stream->is_metadata = 1;
 152         }
 153
 154         stream->in_recv_list = true;
 155
 156         /*
 157          * Add the stream in the recv list of the session. Once the end stream
 158          * message is received, all session streams are published.
 159          */
 160         pthread_mutex_lock(&session->recv_list_lock);
 161         cds_list_add_rcu(&stream->recv_node, &session->recv_list);
 162         session->stream_count++;
 163         pthread_mutex_unlock(&session->recv_list_lock);
 164
 165         /*
 166          * Both in the ctf_trace object and the global stream ht since the data
 167          * side of the relayd does not have the concept of session.
 168          */
 169         lttng_ht_add_unique_u64(relay_streams_ht, &stream->node);
 170         stream->in_stream_ht = true;
 171
 172         DBG("Relay new stream added %s with ID %" PRIu64, stream->channel_name,
 173                         stream->stream_handle);
 174         ret = 0;
 175
 176 end:
 177         if (ret) {
 178                 if (stream->stream_fd) {
 179                         stream_fd_put(stream->stream_fd);
 180                         stream->stream_fd = NULL;
 181                 }
 182                 stream_put(stream);
 183                 stream = NULL;
 184         }
 185         return stream;
 186
 187 error_no_alloc:
 188         /*
 189          * path_name and channel_name need to be freed explicitly here
 190          * because we cannot rely on stream_put().
 191          */
 192         free(path_name);
 193         free(channel_name);
 194         return NULL;
 195 }
 196
 197 /*
 198  * Called with the session lock held.
 199  */
 200 void stream_publish(struct relay_stream *stream)
 201 {
 202         struct relay_session *session;
 203
 204         pthread_mutex_lock(&stream->lock);
 205         if (stream->published) {
 206                 goto unlock;
 207         }
 208
 209         session = stream->trace->session;
 210
 211         pthread_mutex_lock(&session->recv_list_lock);
 212         if (stream->in_recv_list) {
 213                 cds_list_del_rcu(&stream->recv_node);
 214                 stream->in_recv_list = false;
 215         }
 216         pthread_mutex_unlock(&session->recv_list_lock);
 217
 218         pthread_mutex_lock(&stream->trace->stream_list_lock);
 219         cds_list_add_rcu(&stream->stream_node, &stream->trace->stream_list);
 220         pthread_mutex_unlock(&stream->trace->stream_list_lock);
 221
 222         stream->published = true;
 223 unlock:
 224         pthread_mutex_unlock(&stream->lock);
 225 }
 226
 227 /*
 228  * Stream must be protected by holding the stream lock or by virtue of being
 229  * called from stream_destroy, in which case it is guaranteed to be accessed
 230  * from a single thread by the reflock.
 231  */
 232 static void stream_unpublish(struct relay_stream *stream)
 233 {
 234         if (stream->in_stream_ht) {
 235                 struct lttng_ht_iter iter;
 236                 int ret;
 237
 238                 iter.iter.node = &stream->node.node;
 239                 ret = lttng_ht_del(relay_streams_ht, &iter);
 240                 assert(!ret);
 241                 stream->in_stream_ht = false;
 242         }
 243         if (stream->published) {
 244                 pthread_mutex_lock(&stream->trace->stream_list_lock);
 245                 cds_list_del_rcu(&stream->stream_node);
 246                 pthread_mutex_unlock(&stream->trace->stream_list_lock);
 247                 stream->published = false;
 248         }
 249 }
 250
 251 static void stream_destroy(struct relay_stream *stream)
 252 {
 253         if (stream->indexes_ht) {
 254                 /*
 255                  * Calling lttng_ht_destroy in call_rcu worker thread so
 256                  * we don't hold the RCU read-side lock while calling
 257                  * it.
 258                  */
 259                 lttng_ht_destroy(stream->indexes_ht);
 260         }
 261         if (stream->tfa) {
 262                 tracefile_array_destroy(stream->tfa);
 263         }
 264         free(stream->path_name);
 265         free(stream->channel_name);
 266         free(stream);
 267 }
 268
 269 static void stream_destroy_rcu(struct rcu_head *rcu_head)
 270 {
 271         struct relay_stream *stream =
 272                 caa_container_of(rcu_head, struct relay_stream, rcu_node);
 273
 274         stream_destroy(stream);
 275 }
 276
 277 /*
 278  * No need to take stream->lock since this is only called on the final
 279  * stream_put which ensures that a single thread may act on the stream.
 280  *
 281  * At that point, the object is also protected by the reflock which
 282  * guarantees that no other thread may share ownership of this stream.
 283  */
 284 static void stream_release(struct urcu_ref *ref)
 285 {
 286         struct relay_stream *stream =
 287                 caa_container_of(ref, struct relay_stream, ref);
 288         struct relay_session *session;
 289
 290         session = stream->trace->session;
 291
 292         DBG("Releasing stream id %" PRIu64, stream->stream_handle);
 293
 294         pthread_mutex_lock(&session->recv_list_lock);
 295         session->stream_count--;
 296         if (stream->in_recv_list) {
 297                 cds_list_del_rcu(&stream->recv_node);
 298                 stream->in_recv_list = false;
 299         }
 300         pthread_mutex_unlock(&session->recv_list_lock);
 301
 302         stream_unpublish(stream);
 303
 304         if (stream->stream_fd) {
 305                 stream_fd_put(stream->stream_fd);
 306                 stream->stream_fd = NULL;
 307         }
 308         if (stream->index_file) {
 309                 lttng_index_file_put(stream->index_file);
 310                 stream->index_file = NULL;
 311         }
 312         if (stream->trace) {
 313                 ctf_trace_put(stream->trace);
 314                 stream->trace = NULL;
 315         }
 316
 317         call_rcu(&stream->rcu_node, stream_destroy_rcu);
 318 }
 319
 320 void stream_put(struct relay_stream *stream)
 321 {
 322         DBG("stream put for stream id %" PRIu64, stream->stream_handle);
 323         /*
 324          * Ensure existence of stream->reflock for stream unlock.
 325          */
 326         rcu_read_lock();
 327         /*
 328          * Stream reflock ensures that concurrent test and update of
 329          * stream ref is atomic.
 330          */
 331         pthread_mutex_lock(&stream->reflock);
 332         assert(stream->ref.refcount != 0);
 333         /*
 334          * Wait until we have processed all the stream packets before
 335          * actually putting our last stream reference.
 336          */
 337         DBG("stream put stream id %" PRIu64 " refcount %d",
 338                         stream->stream_handle,
 339                         (int) stream->ref.refcount);
 340         urcu_ref_put(&stream->ref, stream_release);
 341         pthread_mutex_unlock(&stream->reflock);
 342         rcu_read_unlock();
 343 }
 344
 345 void try_stream_close(struct relay_stream *stream)
 346 {
 347         bool session_aborted;
 348         struct relay_session *session = stream->trace->session;
 349
 350         DBG("Trying to close stream %" PRIu64, stream->stream_handle);
 351
 352         pthread_mutex_lock(&session->lock);
 353         session_aborted = session->aborted;
 354         pthread_mutex_unlock(&session->lock);
 355
 356         pthread_mutex_lock(&stream->lock);
 357         /*
 358          * Can be called concurently by connection close and reception of last
 359          * pending data.
 360          */
 361         if (stream->closed) {
 362                 pthread_mutex_unlock(&stream->lock);
 363                 DBG("closing stream %" PRIu64 " aborted since it is already marked as closed", stream->stream_handle);
 364                 return;
 365         }
 366
 367         stream->close_requested = true;
 368
 369         if (stream->last_net_seq_num == -1ULL) {
 370                 /*
 371                  * Handle connection close without explicit stream close
 372                  * command.
 373                  *
 374                  * We can be clever about indexes partially received in
 375                  * cases where we received the data socket part, but not
 376                  * the control socket part: since we're currently closing
 377                  * the stream on behalf of the control socket, we *know*
 378                  * there won't be any more control information for this
 379                  * socket. Therefore, we can destroy all indexes for
 380                  * which we have received only the file descriptor (from
 381                  * data socket). This takes care of consumerd crashes
 382                  * between sending the data and control information for
 383                  * a packet. Since those are sent in that order, we take
 384                  * care of consumerd crashes.
 385                  */
 386                 relay_index_close_partial_fd(stream);
 387                 /*
 388                  * Use the highest net_seq_num we currently have pending
 389                  * As end of stream indicator.  Leave last_net_seq_num
 390                  * at -1ULL if we cannot find any index.
 391                  */
 392                 stream->last_net_seq_num = relay_index_find_last(stream);
 393                 /* Fall-through into the next check. */
 394         }
 395
 396         if (stream->last_net_seq_num != -1ULL &&
 397                         ((int64_t) (stream->prev_seq - stream->last_net_seq_num)) < 0
 398                         && !session_aborted) {
 399                 /*
 400                  * Don't close since we still have data pending. This
 401                  * handles cases where an explicit close command has
 402                  * been received for this stream, and cases where the
 403                  * connection has been closed, and we are awaiting for
 404                  * index information from the data socket. It is
 405                  * therefore expected that all the index fd information
 406                  * we need has already been received on the control
 407                  * socket. Matching index information from data socket
 408                  * should be Expected Soon(TM).
 409                  *
 410                  * TODO: We should implement a timer to garbage collect
 411                  * streams after a timeout to be resilient against a
 412                  * consumerd implementation that would not match this
 413                  * expected behavior.
 414                  */
 415                 pthread_mutex_unlock(&stream->lock);
 416                 DBG("closing stream %" PRIu64 " aborted since it still has data pending", stream->stream_handle);
 417                 return;
 418         }
 419         /*
 420          * We received all the indexes we can expect.
 421          */
 422         stream_unpublish(stream);
 423         stream->closed = true;
 424         /* Relay indexes are only used by the "consumer/sessiond" end. */
 425         relay_index_close_all(stream);
 426         pthread_mutex_unlock(&stream->lock);
 427         DBG("Succeeded in closing stream %" PRIu64, stream->stream_handle);
 428         stream_put(stream);
 429 }
 430
 431 static void print_stream_indexes(struct relay_stream *stream)
 432 {
 433         struct lttng_ht_iter iter;
 434         struct relay_index *index;
 435
 436         rcu_read_lock();
 437         cds_lfht_for_each_entry(stream->indexes_ht->ht, &iter.iter, index,
 438                         index_n.node) {
 439                 DBG("index %p net_seq_num %" PRIu64 " refcount %ld"
 440                                 " stream %" PRIu64 " trace %" PRIu64
 441                                 " session %" PRIu64,
 442                                 index,
 443                                 index->index_n.key,
 444                                 stream->ref.refcount,
 445                                 index->stream->stream_handle,
 446                                 index->stream->trace->id,
 447                                 index->stream->trace->session->id);
 448         }
 449         rcu_read_unlock();
 450 }
 451
 452 void print_relay_streams(void)
 453 {
 454         struct lttng_ht_iter iter;
 455         struct relay_stream *stream;
 456
 457         if (!relay_streams_ht) {
 458                 return;
 459         }
 460
 461         rcu_read_lock();
 462         cds_lfht_for_each_entry(relay_streams_ht->ht, &iter.iter, stream,
 463                         node.node) {
 464                 if (!stream_get(stream)) {
 465                         continue;
 466                 }
 467                 DBG("stream %p refcount %ld stream %" PRIu64 " trace %" PRIu64
 468                                 " session %" PRIu64,
 469                                 stream,
 470                                 stream->ref.refcount,
 471                                 stream->stream_handle,
 472                                 stream->trace->id,
 473                                 stream->trace->session->id);
 474                 print_stream_indexes(stream);
 475                 stream_put(stream);
 476         }
 477         rcu_read_unlock();
 478 }