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         if (stream->tracefile_size) {
 141                 DBG("Tracefile %s/%s_0 created", stream->path_name, stream->channel_name);
 142         } else {
 143                 DBG("Tracefile %s/%s created", stream->path_name, stream->channel_name);
 144         }
 145
 146         if (!strncmp(stream->channel_name, DEFAULT_METADATA_NAME, NAME_MAX)) {
 147                 stream->is_metadata = 1;
 148         }
 149
 150         stream->in_recv_list = true;
 151
 152         /*
 153          * Add the stream in the recv list of the session. Once the end stream
 154          * message is received, all session streams are published.
 155          */
 156         pthread_mutex_lock(&session->recv_list_lock);
 157         cds_list_add_rcu(&stream->recv_node, &session->recv_list);
 158         session->stream_count++;
 159         pthread_mutex_unlock(&session->recv_list_lock);
 160
 161         /*
 162          * Both in the ctf_trace object and the global stream ht since the data
 163          * side of the relayd does not have the concept of session.
 164          */
 165         lttng_ht_add_unique_u64(relay_streams_ht, &stream->node);
 166
 167         DBG("Relay new stream added %s with ID %" PRIu64, stream->channel_name,
 168                         stream->stream_handle);
 169         ret = 0;
 170
 171 end:
 172         if (ret) {
 173                 if (stream->stream_fd) {
 174                         stream_fd_put(stream->stream_fd);
 175                         stream->stream_fd = NULL;
 176                 }
 177                 stream_put(stream);
 178                 stream = NULL;
 179         }
 180         return stream;
 181
 182 error_no_alloc:
 183         /*
 184          * path_name and channel_name need to be freed explicitly here
 185          * because we cannot rely on stream_put().
 186          */
 187         free(path_name);
 188         free(channel_name);
 189         return NULL;
 190 }
 191
 192 /*
 193  * Called with the session lock held.
 194  */
 195 void stream_publish(struct relay_stream *stream)
 196 {
 197         struct relay_session *session;
 198
 199         pthread_mutex_lock(&stream->lock);
 200         if (stream->published) {
 201                 goto unlock;
 202         }
 203
 204         session = stream->trace->session;
 205
 206         pthread_mutex_lock(&session->recv_list_lock);
 207         if (stream->in_recv_list) {
 208                 cds_list_del_rcu(&stream->recv_node);
 209                 stream->in_recv_list = false;
 210         }
 211         pthread_mutex_unlock(&session->recv_list_lock);
 212
 213         pthread_mutex_lock(&stream->trace->stream_list_lock);
 214         cds_list_add_rcu(&stream->stream_node, &stream->trace->stream_list);
 215         pthread_mutex_unlock(&stream->trace->stream_list_lock);
 216
 217         stream->published = true;
 218 unlock:
 219         pthread_mutex_unlock(&stream->lock);
 220 }
 221
 222 /*
 223  * Only called from destroy. No stream lock needed, since there is a
 224  * single user at this point. This is ensured by having the refcount
 225  * reaching 0.
 226  */
 227 static void stream_unpublish(struct relay_stream *stream)
 228 {
 229         if (!stream->published) {
 230                 return;
 231         }
 232         pthread_mutex_lock(&stream->trace->stream_list_lock);
 233         cds_list_del_rcu(&stream->stream_node);
 234         pthread_mutex_unlock(&stream->trace->stream_list_lock);
 235
 236         stream->published = false;
 237 }
 238
 239 static void stream_destroy(struct relay_stream *stream)
 240 {
 241         if (stream->indexes_ht) {
 242                 lttng_ht_destroy(stream->indexes_ht);
 243         }
 244         free(stream->path_name);
 245         free(stream->channel_name);
 246         free(stream);
 247 }
 248
 249 static void stream_destroy_rcu(struct rcu_head *rcu_head)
 250 {
 251         struct relay_stream *stream =
 252                 caa_container_of(rcu_head, struct relay_stream, rcu_node);
 253
 254         stream_destroy(stream);
 255 }
 256
 257 /*
 258  * No need to take stream->lock since this is only called on the final
 259  * stream_put which ensures that a single thread may act on the stream.
 260  *
 261  * At that point, the object is also protected by the reflock which
 262  * guarantees that no other thread may share ownership of this stream.
 263  */
 264 static void stream_release(struct urcu_ref *ref)
 265 {
 266         struct relay_stream *stream =
 267                 caa_container_of(ref, struct relay_stream, ref);
 268         struct relay_session *session;
 269         int ret;
 270         struct lttng_ht_iter iter;
 271
 272         session = stream->trace->session;
 273
 274         DBG("Releasing stream id %" PRIu64, stream->stream_handle);
 275
 276         pthread_mutex_lock(&session->recv_list_lock);
 277         session->stream_count--;
 278         if (stream->in_recv_list) {
 279                 cds_list_del_rcu(&stream->recv_node);
 280                 stream->in_recv_list = false;
 281         }
 282         pthread_mutex_unlock(&session->recv_list_lock);
 283
 284         iter.iter.node = &stream->node.node;
 285         ret = lttng_ht_del(relay_streams_ht, &iter);
 286         assert(!ret);
 287
 288         stream_unpublish(stream);
 289
 290         if (stream->stream_fd) {
 291                 stream_fd_put(stream->stream_fd);
 292                 stream->stream_fd = NULL;
 293         }
 294         if (stream->index_fd) {
 295                 stream_fd_put(stream->index_fd);
 296                 stream->index_fd = NULL;
 297         }
 298         if (stream->trace) {
 299                 ctf_trace_put(stream->trace);
 300                 stream->trace = NULL;
 301         }
 302
 303         call_rcu(&stream->rcu_node, stream_destroy_rcu);
 304 }
 305
 306 void stream_put(struct relay_stream *stream)
 307 {
 308         DBG("stream put for stream id %" PRIu64, stream->stream_handle);
 309         /*
 310          * Ensure existence of stream->reflock for stream unlock.
 311          */
 312         rcu_read_lock();
 313         /*
 314          * Stream reflock ensures that concurrent test and update of
 315          * stream ref is atomic.
 316          */
 317         pthread_mutex_lock(&stream->reflock);
 318         assert(stream->ref.refcount != 0);
 319         /*
 320          * Wait until we have processed all the stream packets before
 321          * actually putting our last stream reference.
 322          */
 323         DBG("stream put stream id %" PRIu64 " refcount %d",
 324                         stream->stream_handle,
 325                         (int) stream->ref.refcount);
 326         urcu_ref_put(&stream->ref, stream_release);
 327         pthread_mutex_unlock(&stream->reflock);
 328         rcu_read_unlock();
 329 }
 330
 331 void stream_close(struct relay_stream *stream)
 332 {
 333         DBG("closing stream %" PRIu64, stream->stream_handle);
 334         pthread_mutex_lock(&stream->lock);
 335         stream->closed = true;
 336         relay_index_close_all(stream);
 337         pthread_mutex_unlock(&stream->lock);
 338         stream_put(stream);
 339 }
 340
 341 void print_relay_streams(void)
 342 {
 343         struct lttng_ht_iter iter;
 344         struct relay_stream *stream;
 345
 346         rcu_read_lock();
 347         cds_lfht_for_each_entry(relay_streams_ht->ht, &iter.iter, stream,
 348                         node.node) {
 349                 if (!stream_get(stream)) {
 350                         continue;
 351                 }
 352                 DBG("stream %p refcount %ld stream %" PRIu64 " trace %" PRIu64
 353                                 " session %" PRIu64,
 354                                 stream,
 355                                 stream->ref.refcount,
 356                                 stream->stream_handle,
 357                                 stream->trace->id,
 358                                 stream->trace->session->id);
 359                 stream_put(stream);
 360         }
 361         rcu_read_unlock();
 362 }