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