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