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 #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->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, 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
 171         DBG("Relay new stream added %s with ID %" PRIu64, stream->channel_name,
 172                         stream->stream_handle);
 173         ret = 0;
 174
 175 end:
 176         if (ret) {
 177                 if (stream->stream_fd) {
 178                         stream_fd_put(stream->stream_fd);
 179                         stream->stream_fd = NULL;
 180                 }
 181                 stream_put(stream);
 182                 stream = NULL;
 183         }
 184         return stream;
 185
 186 error_no_alloc:
 187         /*
 188          * path_name and channel_name need to be freed explicitly here
 189          * because we cannot rely on stream_put().
 190          */
 191         free(path_name);
 192         free(channel_name);
 193         return NULL;
 194 }
 195
 196 /*
 197  * Called with the session lock held.
 198  */
 199 void stream_publish(struct relay_stream *stream)
 200 {
 201         struct relay_session *session;
 202
 203         pthread_mutex_lock(&stream->lock);
 204         if (stream->published) {
 205                 goto unlock;
 206         }
 207
 208         session = stream->trace->session;
 209
 210         pthread_mutex_lock(&session->recv_list_lock);
 211         if (stream->in_recv_list) {
 212                 cds_list_del_rcu(&stream->recv_node);
 213                 stream->in_recv_list = false;
 214         }
 215         pthread_mutex_unlock(&session->recv_list_lock);
 216
 217         pthread_mutex_lock(&stream->trace->stream_list_lock);
 218         cds_list_add_rcu(&stream->stream_node, &stream->trace->stream_list);
 219         pthread_mutex_unlock(&stream->trace->stream_list_lock);
 220
 221         stream->published = true;
 222 unlock:
 223         pthread_mutex_unlock(&stream->lock);
 224 }
 225
 226 /*
 227  * Only called from destroy. No stream lock needed, since there is a
 228  * single user at this point. This is ensured by having the refcount
 229  * reaching 0.
 230  */
 231 static void stream_unpublish(struct relay_stream *stream)
 232 {
 233         if (!stream->published) {
 234                 return;
 235         }
 236         pthread_mutex_lock(&stream->trace->stream_list_lock);
 237         cds_list_del_rcu(&stream->stream_node);
 238         pthread_mutex_unlock(&stream->trace->stream_list_lock);
 239
 240         stream->published = false;
 241 }
 242
 243 static void stream_destroy(struct relay_stream *stream)
 244 {
 245         if (stream->indexes_ht) {
 246                 lttng_ht_destroy(stream->indexes_ht);
 247         }
 248         if (stream->tfa) {
 249                 tracefile_array_destroy(stream->tfa);
 250         }
 251         free(stream->path_name);
 252         free(stream->channel_name);
 253         free(stream);
 254 }
 255
 256 static void stream_destroy_rcu(struct rcu_head *rcu_head)
 257 {
 258         struct relay_stream *stream =
 259                 caa_container_of(rcu_head, struct relay_stream, rcu_node);
 260
 261         stream_destroy(stream);
 262 }
 263
 264 /*
 265  * No need to take stream->lock since this is only called on the final
 266  * stream_put which ensures that a single thread may act on the stream.
 267  *
 268  * At that point, the object is also protected by the reflock which
 269  * guarantees that no other thread may share ownership of this stream.
 270  */
 271 static void stream_release(struct urcu_ref *ref)
 272 {
 273         struct relay_stream *stream =
 274                 caa_container_of(ref, struct relay_stream, ref);
 275         struct relay_session *session;
 276         int ret;
 277         struct lttng_ht_iter iter;
 278
 279         session = stream->trace->session;
 280
 281         DBG("Releasing stream id %" PRIu64, stream->stream_handle);
 282
 283         pthread_mutex_lock(&session->recv_list_lock);
 284         session->stream_count--;
 285         if (stream->in_recv_list) {
 286                 cds_list_del_rcu(&stream->recv_node);
 287                 stream->in_recv_list = false;
 288         }
 289         pthread_mutex_unlock(&session->recv_list_lock);
 290
 291         iter.iter.node = &stream->node.node;
 292         ret = lttng_ht_del(relay_streams_ht, &iter);
 293         assert(!ret);
 294
 295         stream_unpublish(stream);
 296
 297         if (stream->stream_fd) {
 298                 stream_fd_put(stream->stream_fd);
 299                 stream->stream_fd = NULL;
 300         }
 301         if (stream->index_fd) {
 302                 stream_fd_put(stream->index_fd);
 303                 stream->index_fd = NULL;
 304         }
 305         if (stream->trace) {
 306                 ctf_trace_put(stream->trace);
 307                 stream->trace = NULL;
 308         }
 309
 310         call_rcu(&stream->rcu_node, stream_destroy_rcu);
 311 }
 312
 313 void stream_put(struct relay_stream *stream)
 314 {
 315         DBG("stream put for stream id %" PRIu64, stream->stream_handle);
 316         /*
 317          * Ensure existence of stream->reflock for stream unlock.
 318          */
 319         rcu_read_lock();
 320         /*
 321          * Stream reflock ensures that concurrent test and update of
 322          * stream ref is atomic.
 323          */
 324         pthread_mutex_lock(&stream->reflock);
 325         assert(stream->ref.refcount != 0);
 326         /*
 327          * Wait until we have processed all the stream packets before
 328          * actually putting our last stream reference.
 329          */
 330         DBG("stream put stream id %" PRIu64 " refcount %d",
 331                         stream->stream_handle,
 332                         (int) stream->ref.refcount);
 333         urcu_ref_put(&stream->ref, stream_release);
 334         pthread_mutex_unlock(&stream->reflock);
 335         rcu_read_unlock();
 336 }
 337
 338 void stream_close(struct relay_stream *stream)
 339 {
 340         DBG("closing stream %" PRIu64, stream->stream_handle);
 341         pthread_mutex_lock(&stream->lock);
 342         stream->closed = true;
 343         relay_index_close_all(stream);
 344         pthread_mutex_unlock(&stream->lock);
 345         stream_put(stream);
 346 }
 347
 348 void print_relay_streams(void)
 349 {
 350         struct lttng_ht_iter iter;
 351         struct relay_stream *stream;
 352
 353         rcu_read_lock();
 354         cds_lfht_for_each_entry(relay_streams_ht->ht, &iter.iter, stream,
 355                         node.node) {
 356                 if (!stream_get(stream)) {
 357                         continue;
 358                 }
 359                 DBG("stream %p refcount %ld stream %" PRIu64 " trace %" PRIu64
 360                                 " session %" PRIu64,
 361                                 stream,
 362                                 stream->ref.refcount,
 363                                 stream->stream_handle,
 364                                 stream->trace->id,
 365                                 stream->trace->session->id);
 366                 stream_put(stream);
 367         }
 368         rcu_read_unlock();
 369 }