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         if (stream->tracefile_size) {
 140                 DBG("Tracefile %s/%s_0 created", stream->path_name, stream->channel_name);
 141         } else {
 142                 DBG("Tracefile %s/%s created", stream->path_name, stream->channel_name);
 143         }
 144
 145         if (!strncmp(stream->channel_name, DEFAULT_METADATA_NAME, NAME_MAX)) {
 146                 stream->is_metadata = 1;
 147         }
 148
 149         stream->in_recv_list = true;
 150
 151         /*
 152          * Add the stream in the recv list of the session. Once the end stream
 153          * message is received, all session streams are published.
 154          */
 155         pthread_mutex_lock(&session->recv_list_lock);
 156         cds_list_add_rcu(&stream->recv_node, &session->recv_list);
 157         session->stream_count++;
 158         pthread_mutex_unlock(&session->recv_list_lock);
 159
 160         /*
 161          * Both in the ctf_trace object and the global stream ht since the data
 162          * side of the relayd does not have the concept of session.
 163          */
 164         lttng_ht_add_unique_u64(relay_streams_ht, &stream->node);
 165
 166         DBG("Relay new stream added %s with ID %" PRIu64, stream->channel_name,
 167                         stream->stream_handle);
 168         ret = 0;
 169
 170 end:
 171         if (ret) {
 172                 if (stream->stream_fd) {
 173                         stream_fd_put(stream->stream_fd);
 174                         stream->stream_fd = NULL;
 175                 }
 176                 stream_put(stream);
 177                 stream = NULL;
 178         }
 179         return stream;
 180
 181 error_no_alloc:
 182         /*
 183          * path_name and channel_name need to be freed explicitly here
 184          * because we cannot rely on stream_put().
 185          */
 186         free(path_name);
 187         free(channel_name);
 188         return NULL;
 189 }
 190
 191 /*
 192  * Called with the session lock held.
 193  */
 194 void stream_publish(struct relay_stream *stream)
 195 {
 196         struct relay_session *session;
 197
 198         pthread_mutex_lock(&stream->lock);
 199         if (stream->published) {
 200                 goto unlock;
 201         }
 202
 203         session = stream->trace->session;
 204
 205         pthread_mutex_lock(&session->recv_list_lock);
 206         if (stream->in_recv_list) {
 207                 cds_list_del_rcu(&stream->recv_node);
 208                 stream->in_recv_list = false;
 209         }
 210         pthread_mutex_unlock(&session->recv_list_lock);
 211
 212         pthread_mutex_lock(&stream->trace->stream_list_lock);
 213         cds_list_add_rcu(&stream->stream_node, &stream->trace->stream_list);
 214         pthread_mutex_unlock(&stream->trace->stream_list_lock);
 215
 216         stream->published = true;
 217 unlock:
 218         pthread_mutex_unlock(&stream->lock);
 219 }
 220
 221 /*
 222  * Only called from destroy. No stream lock needed, since there is a
 223  * single user at this point. This is ensured by having the refcount
 224  * reaching 0.
 225  */
 226 static void stream_unpublish(struct relay_stream *stream)
 227 {
 228         if (!stream->published) {
 229                 return;
 230         }
 231         pthread_mutex_lock(&stream->trace->stream_list_lock);
 232         cds_list_del_rcu(&stream->stream_node);
 233         pthread_mutex_unlock(&stream->trace->stream_list_lock);
 234
 235         stream->published = false;
 236 }
 237
 238 static void stream_destroy(struct relay_stream *stream)
 239 {
 240         if (stream->indexes_ht) {
 241                 lttng_ht_destroy(stream->indexes_ht);
 242         }
 243         free(stream->path_name);
 244         free(stream->channel_name);
 245         free(stream);
 246 }
 247
 248 static void stream_destroy_rcu(struct rcu_head *rcu_head)
 249 {
 250         struct relay_stream *stream =
 251                 caa_container_of(rcu_head, struct relay_stream, rcu_node);
 252
 253         stream_destroy(stream);
 254 }
 255
 256 /*
 257  * No need to take stream->lock since this is only called on the final
 258  * stream_put which ensures that a single thread may act on the stream.
 259  *
 260  * At that point, the object is also protected by the reflock which
 261  * guarantees that no other thread may share ownership of this stream.
 262  */
 263 static void stream_release(struct urcu_ref *ref)
 264 {
 265         struct relay_stream *stream =
 266                 caa_container_of(ref, struct relay_stream, ref);
 267         struct relay_session *session;
 268         int ret;
 269         struct lttng_ht_iter iter;
 270
 271         session = stream->trace->session;
 272
 273         DBG("Releasing stream id %" PRIu64, stream->stream_handle);
 274
 275         pthread_mutex_lock(&session->recv_list_lock);
 276         session->stream_count--;
 277         if (stream->in_recv_list) {
 278                 cds_list_del_rcu(&stream->recv_node);
 279                 stream->in_recv_list = false;
 280         }
 281         pthread_mutex_unlock(&session->recv_list_lock);
 282
 283         iter.iter.node = &stream->node.node;
 284         ret = lttng_ht_del(relay_streams_ht, &iter);
 285         assert(!ret);
 286
 287         stream_unpublish(stream);
 288
 289         if (stream->stream_fd) {
 290                 stream_fd_put(stream->stream_fd);
 291                 stream->stream_fd = NULL;
 292         }
 293         if (stream->index_fd) {
 294                 stream_fd_put(stream->index_fd);
 295                 stream->index_fd = NULL;
 296         }
 297         if (stream->trace) {
 298                 ctf_trace_put(stream->trace);
 299                 stream->trace = NULL;
 300         }
 301
 302         call_rcu(&stream->rcu_node, stream_destroy_rcu);
 303 }
 304
 305 void stream_put(struct relay_stream *stream)
 306 {
 307         DBG("stream put for stream id %" PRIu64, stream->stream_handle);
 308         /*
 309          * Ensure existence of stream->reflock for stream unlock.
 310          */
 311         rcu_read_lock();
 312         /*
 313          * Stream reflock ensures that concurrent test and update of
 314          * stream ref is atomic.
 315          */
 316         pthread_mutex_lock(&stream->reflock);
 317         assert(stream->ref.refcount != 0);
 318         /*
 319          * Wait until we have processed all the stream packets before
 320          * actually putting our last stream reference.
 321          */
 322         DBG("stream put stream id %" PRIu64 " refcount %d",
 323                         stream->stream_handle,
 324                         (int) stream->ref.refcount);
 325         urcu_ref_put(&stream->ref, stream_release);
 326         pthread_mutex_unlock(&stream->reflock);
 327         rcu_read_unlock();
 328 }
 329
 330 void stream_close(struct relay_stream *stream)
 331 {
 332         DBG("closing stream %" PRIu64, stream->stream_handle);
 333         pthread_mutex_lock(&stream->lock);
 334         relay_index_close_all(stream);
 335         pthread_mutex_unlock(&stream->lock);
 336         stream_put(stream);
 337 }
 338
 339 void print_relay_streams(void)
 340 {
 341         struct lttng_ht_iter iter;
 342         struct relay_stream *stream;
 343
 344         rcu_read_lock();
 345         cds_lfht_for_each_entry(relay_streams_ht->ht, &iter.iter, stream,
 346                         node.node) {
 347                 if (!stream_get(stream)) {
 348                         continue;
 349                 }
 350                 DBG("stream %p refcount %ld stream %" PRIu64 " trace %" PRIu64
 351                                 " session %" PRIu64,
 352                                 stream,
 353                                 stream->ref.refcount,
 354                                 stream->stream_handle,
 355                                 stream->trace->id,
 356                                 stream->trace->session->id);
 357                 stream_put(stream);
 358         }
 359         rcu_read_unlock();
 360 }