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, 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                 lttng_ht_destroy(stream->indexes_ht);
 257         }
 258         if (stream->tfa) {
 259                 tracefile_array_destroy(stream->tfa);
 260         }
 261         free(stream->path_name);
 262         free(stream->channel_name);
 263         free(stream);
 264 }
 265
 266 static void stream_destroy_rcu(struct rcu_head *rcu_head)
 267 {
 268         struct relay_stream *stream =
 269                 caa_container_of(rcu_head, struct relay_stream, rcu_node);
 270
 271         stream_destroy(stream);
 272 }
 273
 274 /*
 275  * No need to take stream->lock since this is only called on the final
 276  * stream_put which ensures that a single thread may act on the stream.
 277  *
 278  * At that point, the object is also protected by the reflock which
 279  * guarantees that no other thread may share ownership of this stream.
 280  */
 281 static void stream_release(struct urcu_ref *ref)
 282 {
 283         struct relay_stream *stream =
 284                 caa_container_of(ref, struct relay_stream, ref);
 285         struct relay_session *session;
 286
 287         session = stream->trace->session;
 288
 289         DBG("Releasing stream id %" PRIu64, stream->stream_handle);
 290
 291         pthread_mutex_lock(&session->recv_list_lock);
 292         session->stream_count--;
 293         if (stream->in_recv_list) {
 294                 cds_list_del_rcu(&stream->recv_node);
 295                 stream->in_recv_list = false;
 296         }
 297         pthread_mutex_unlock(&session->recv_list_lock);
 298
 299         stream_unpublish(stream);
 300
 301         if (stream->stream_fd) {
 302                 stream_fd_put(stream->stream_fd);
 303                 stream->stream_fd = NULL;
 304         }
 305         if (stream->index_fd) {
 306                 stream_fd_put(stream->index_fd);
 307                 stream->index_fd = NULL;
 308         }
 309         if (stream->trace) {
 310                 ctf_trace_put(stream->trace);
 311                 stream->trace = NULL;
 312         }
 313
 314         call_rcu(&stream->rcu_node, stream_destroy_rcu);
 315 }
 316
 317 void stream_put(struct relay_stream *stream)
 318 {
 319         DBG("stream put for stream id %" PRIu64, stream->stream_handle);
 320         /*
 321          * Ensure existence of stream->reflock for stream unlock.
 322          */
 323         rcu_read_lock();
 324         /*
 325          * Stream reflock ensures that concurrent test and update of
 326          * stream ref is atomic.
 327          */
 328         pthread_mutex_lock(&stream->reflock);
 329         assert(stream->ref.refcount != 0);
 330         /*
 331          * Wait until we have processed all the stream packets before
 332          * actually putting our last stream reference.
 333          */
 334         DBG("stream put stream id %" PRIu64 " refcount %d",
 335                         stream->stream_handle,
 336                         (int) stream->ref.refcount);
 337         urcu_ref_put(&stream->ref, stream_release);
 338         pthread_mutex_unlock(&stream->reflock);
 339         rcu_read_unlock();
 340 }
 341
 342 void try_stream_close(struct relay_stream *stream)
 343 {
 344         DBG("Trying to close stream %" PRIu64, stream->stream_handle);
 345         pthread_mutex_lock(&stream->lock);
 346         /*
 347          * Can be called concurently by connection close and reception of last
 348          * pending data.
 349          */
 350         if (stream->closed) {
 351                 pthread_mutex_unlock(&stream->lock);
 352                 DBG("closing stream %" PRIu64 " aborted since it is already marked as closed", stream->stream_handle);
 353                 return;
 354         }
 355
 356         stream->close_requested = true;
 357         /*
 358          * We shortcut the data pending check if no bound is known for this
 359          * stream. This prevents us from never closing the stream in the case
 360          * where a connection would be closed before a "close" command has
 361          * been received.
 362          *
 363          * TODO
 364          * This still leaves open the question of handling missing data after
 365          * a bound has been set by a stream close command. Since we have no
 366          * way of pairing data and control connection, and that a data
 367          * connection has no ownership of a stream, it is likely that a
 368          * timeout approach would be appropriate to handle dangling streams.
 369          */
 370         if (stream->last_net_seq_num != -1ULL &&
 371                         ((int64_t) (stream->prev_seq - stream->last_net_seq_num)) < 0) {
 372                 /* Don't close since we still have data pending. */
 373                 pthread_mutex_unlock(&stream->lock);
 374                 DBG("closing stream %" PRIu64 " aborted since it still has data pending", stream->stream_handle);
 375                 return;
 376         }
 377         stream_unpublish(stream);
 378         stream->closed = true;
 379         /* Relay indexes are only used by the "consumer/sessiond" end. */
 380         relay_index_close_all(stream);
 381         pthread_mutex_unlock(&stream->lock);
 382         DBG("Succeeded in closing stream %" PRIu64, stream->stream_handle);
 383         stream_put(stream);
 384 }
 385
 386 void print_relay_streams(void)
 387 {
 388         struct lttng_ht_iter iter;
 389         struct relay_stream *stream;
 390
 391         rcu_read_lock();
 392         cds_lfht_for_each_entry(relay_streams_ht->ht, &iter.iter, stream,
 393                         node.node) {
 394                 if (!stream_get(stream)) {
 395                         continue;
 396                 }
 397                 DBG("stream %p refcount %ld stream %" PRIu64 " trace %" PRIu64
 398                                 " session %" PRIu64,
 399                                 stream,
 400                                 stream->ref.refcount,
 401                                 stream->stream_handle,
 402                                 stream->trace->id,
 403                                 stream->trace->session->id);
 404                 stream_put(stream);
 405         }
 406         rcu_read_unlock();
 407 }