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->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, 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                 lttng_ht_destroy(stream->indexes_ht);
 256         }
 257         if (stream->tfa) {
 258                 tracefile_array_destroy(stream->tfa);
 259         }
 260         free(stream->path_name);
 261         free(stream->channel_name);
 262         free(stream);
 263 }
 264
 265 static void stream_destroy_rcu(struct rcu_head *rcu_head)
 266 {
 267         struct relay_stream *stream =
 268                 caa_container_of(rcu_head, struct relay_stream, rcu_node);
 269
 270         stream_destroy(stream);
 271 }
 272
 273 /*
 274  * No need to take stream->lock since this is only called on the final
 275  * stream_put which ensures that a single thread may act on the stream.
 276  *
 277  * At that point, the object is also protected by the reflock which
 278  * guarantees that no other thread may share ownership of this stream.
 279  */
 280 static void stream_release(struct urcu_ref *ref)
 281 {
 282         struct relay_stream *stream =
 283                 caa_container_of(ref, struct relay_stream, ref);
 284         struct relay_session *session;
 285
 286         session = stream->trace->session;
 287
 288         DBG("Releasing stream id %" PRIu64, stream->stream_handle);
 289
 290         pthread_mutex_lock(&session->recv_list_lock);
 291         session->stream_count--;
 292         if (stream->in_recv_list) {
 293                 cds_list_del_rcu(&stream->recv_node);
 294                 stream->in_recv_list = false;
 295         }
 296         pthread_mutex_unlock(&session->recv_list_lock);
 297
 298         stream_unpublish(stream);
 299
 300         if (stream->stream_fd) {
 301                 stream_fd_put(stream->stream_fd);
 302                 stream->stream_fd = NULL;
 303         }
 304         if (stream->index_fd) {
 305                 stream_fd_put(stream->index_fd);
 306                 stream->index_fd = NULL;
 307         }
 308         if (stream->trace) {
 309                 ctf_trace_put(stream->trace);
 310                 stream->trace = NULL;
 311         }
 312
 313         call_rcu(&stream->rcu_node, stream_destroy_rcu);
 314 }
 315
 316 void stream_put(struct relay_stream *stream)
 317 {
 318         DBG("stream put for stream id %" PRIu64, stream->stream_handle);
 319         /*
 320          * Ensure existence of stream->reflock for stream unlock.
 321          */
 322         rcu_read_lock();
 323         /*
 324          * Stream reflock ensures that concurrent test and update of
 325          * stream ref is atomic.
 326          */
 327         pthread_mutex_lock(&stream->reflock);
 328         assert(stream->ref.refcount != 0);
 329         /*
 330          * Wait until we have processed all the stream packets before
 331          * actually putting our last stream reference.
 332          */
 333         DBG("stream put stream id %" PRIu64 " refcount %d",
 334                         stream->stream_handle,
 335                         (int) stream->ref.refcount);
 336         urcu_ref_put(&stream->ref, stream_release);
 337         pthread_mutex_unlock(&stream->reflock);
 338         rcu_read_unlock();
 339 }
 340
 341 void stream_close(struct relay_stream *stream)
 342 {
 343         DBG("closing stream %" PRIu64, stream->stream_handle);
 344         pthread_mutex_lock(&stream->lock);
 345         stream_unpublish(stream);
 346         stream->closed = true;
 347         relay_index_close_all(stream);
 348         pthread_mutex_unlock(&stream->lock);
 349         stream_put(stream);
 350 }
 351
 352 void print_relay_streams(void)
 353 {
 354         struct lttng_ht_iter iter;
 355         struct relay_stream *stream;
 356
 357         rcu_read_lock();
 358         cds_lfht_for_each_entry(relay_streams_ht->ht, &iter.iter, stream,
 359                         node.node) {
 360                 if (!stream_get(stream)) {
 361                         continue;
 362                 }
 363                 DBG("stream %p refcount %ld stream %" PRIu64 " trace %" PRIu64
 364                                 " session %" PRIu64,
 365                                 stream,
 366                                 stream->ref.refcount,
 367                                 stream->stream_handle,
 368                                 stream->trace->id,
 369                                 stream->trace->session->id);
 370                 stream_put(stream);
 371         }
 372         rcu_read_unlock();
 373 }