src/common/consumer-stream.c

   1 /*
   2  * Copyright (C) 2011 - Julien Desfossez <julien.desfossez@polymtl.ca>
   3  *                      Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   4  * Copyright (C) 2013 - David Goulet <dgoulet@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 <assert.h>
  22 #include <inttypes.h>
  23 #include <sys/mman.h>
  24 #include <unistd.h>
  25
  26 #include <common/common.h>
  27 #include <common/relayd/relayd.h>
  28 #include <common/ust-consumer/ust-consumer.h>
  29
  30 #include "consumer-stream.h"
  31
  32 /*
  33  * RCU call to free stream. MUST only be used with call_rcu().
  34  */
  35 static void free_stream_rcu(struct rcu_head *head)
  36 {
  37         struct lttng_ht_node_u64 *node =
  38                 caa_container_of(head, struct lttng_ht_node_u64, head);
  39         struct lttng_consumer_stream *stream =
  40                 caa_container_of(node, struct lttng_consumer_stream, node);
  41
  42         pthread_mutex_destroy(&stream->lock);
  43         free(stream);
  44 }
  45
  46 /*
  47  * Close stream on the relayd side. This call can destroy a relayd if the
  48  * conditions are met.
  49  *
  50  * A RCU read side lock MUST be acquired if the relayd object was looked up in
  51  * a hash table before calling this.
  52  */
  53 void consumer_stream_relayd_close(struct lttng_consumer_stream *stream,
  54                 struct consumer_relayd_sock_pair *relayd)
  55 {
  56         int ret;
  57
  58         assert(stream);
  59         assert(relayd);
  60
  61         if (stream->sent_to_relayd) {
  62                 uatomic_dec(&relayd->refcount);
  63                 assert(uatomic_read(&relayd->refcount) >= 0);
  64         }
  65
  66         /* Closing streams requires to lock the control socket. */
  67         pthread_mutex_lock(&relayd->ctrl_sock_mutex);
  68         ret = relayd_send_close_stream(&relayd->control_sock,
  69                         stream->relayd_stream_id,
  70                         stream->next_net_seq_num - 1);
  71         pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
  72         if (ret < 0) {
  73                 DBG("Unable to close stream on the relayd. Continuing");
  74                 /*
  75                  * Continue here. There is nothing we can do for the relayd.
  76                  * Chances are that the relayd has closed the socket so we just
  77                  * continue cleaning up.
  78                  */
  79         }
  80
  81         /* Both conditions are met, we destroy the relayd. */
  82         if (uatomic_read(&relayd->refcount) == 0 &&
  83                         uatomic_read(&relayd->destroy_flag)) {
  84                 consumer_destroy_relayd(relayd);
  85         }
  86         stream->net_seq_idx = (uint64_t) -1ULL;
  87         stream->sent_to_relayd = 0;
  88 }
  89
  90 /*
  91  * Close stream's file descriptors and, if needed, close stream also on the
  92  * relayd side.
  93  *
  94  * The consumer data lock MUST be acquired.
  95  * The stream lock MUST be acquired.
  96  */
  97 void consumer_stream_close(struct lttng_consumer_stream *stream)
  98 {
  99         int ret;
 100         struct consumer_relayd_sock_pair *relayd;
 101
 102         assert(stream);
 103
 104         switch (consumer_data.type) {
 105         case LTTNG_CONSUMER_KERNEL:
 106                 if (stream->mmap_base != NULL) {
 107                         ret = munmap(stream->mmap_base, stream->mmap_len);
 108                         if (ret != 0) {
 109                                 PERROR("munmap");
 110                         }
 111                 }
 112
 113                 if (stream->wait_fd >= 0) {
 114                         ret = close(stream->wait_fd);
 115                         if (ret) {
 116                                 PERROR("close");
 117                         }
 118                         stream->wait_fd = -1;
 119                 }
 120                 break;
 121         case LTTNG_CONSUMER32_UST:
 122         case LTTNG_CONSUMER64_UST:
 123                 break;
 124         default:
 125                 ERR("Unknown consumer_data type");
 126                 assert(0);
 127         }
 128
 129         /* Close output fd. Could be a socket or local file at this point. */
 130         if (stream->out_fd >= 0) {
 131                 ret = close(stream->out_fd);
 132                 if (ret) {
 133                         PERROR("close");
 134                 }
 135                 stream->out_fd = -1;
 136         }
 137
 138         /* Check and cleanup relayd if needed. */
 139         rcu_read_lock();
 140         relayd = consumer_find_relayd(stream->net_seq_idx);
 141         if (relayd != NULL) {
 142                 consumer_stream_relayd_close(stream, relayd);
 143         }
 144         rcu_read_unlock();
 145 }
 146
 147 /*
 148  * Delete the stream from all possible hash tables.
 149  *
 150  * The consumer data lock MUST be acquired.
 151  * The stream lock MUST be acquired.
 152  */
 153 void consumer_stream_delete(struct lttng_consumer_stream *stream,
 154                 struct lttng_ht *ht)
 155 {
 156         int ret;
 157         struct lttng_ht_iter iter;
 158
 159         assert(stream);
 160         /* Should NEVER be called not in monitor mode. */
 161         assert(stream->chan->monitor);
 162
 163         rcu_read_lock();
 164
 165         if (ht) {
 166                 iter.iter.node = &stream->node.node;
 167                 ret = lttng_ht_del(ht, &iter);
 168                 assert(!ret);
 169         }
 170
 171         /* Delete from stream per channel ID hash table. */
 172         iter.iter.node = &stream->node_channel_id.node;
 173         /*
 174          * The returned value is of no importance. Even if the node is NOT in the
 175          * hash table, we continue since we may have been called by a code path
 176          * that did not add the stream to a (all) hash table. Same goes for the
 177          * next call ht del call.
 178          */
 179         (void) lttng_ht_del(consumer_data.stream_per_chan_id_ht, &iter);
 180
 181         /* Delete from the global stream list. */
 182         iter.iter.node = &stream->node_session_id.node;
 183         /* See the previous ht del on why we ignore the returned value. */
 184         (void) lttng_ht_del(consumer_data.stream_list_ht, &iter);
 185
 186         rcu_read_unlock();
 187
 188         /* Decrement the stream count of the global consumer data. */
 189         assert(consumer_data.stream_count > 0);
 190         consumer_data.stream_count--;
 191 }
 192
 193 /*
 194  * Free the given stream within a RCU call.
 195  */
 196 void consumer_stream_free(struct lttng_consumer_stream *stream)
 197 {
 198         assert(stream);
 199
 200         call_rcu(&stream->node.head, free_stream_rcu);
 201 }
 202
 203 /*
 204  * Destroy the stream's buffers of the tracer.
 205  */
 206 void consumer_stream_destroy_buffers(struct lttng_consumer_stream *stream)
 207 {
 208         assert(stream);
 209
 210         switch (consumer_data.type) {
 211         case LTTNG_CONSUMER_KERNEL:
 212                 break;
 213         case LTTNG_CONSUMER32_UST:
 214         case LTTNG_CONSUMER64_UST:
 215                 lttng_ustconsumer_del_stream(stream);
 216                 break;
 217         default:
 218                 ERR("Unknown consumer_data type");
 219                 assert(0);
 220         }
 221 }
 222
 223 /*
 224  * Destroy and close a already created stream.
 225  */
 226 static void destroy_close_stream(struct lttng_consumer_stream *stream)
 227 {
 228         assert(stream);
 229
 230         DBG("Consumer stream destroy monitored key: %" PRIu64, stream->key);
 231
 232         /* Destroy tracer buffers of the stream. */
 233         consumer_stream_destroy_buffers(stream);
 234         /* Close down everything including the relayd if one. */
 235         consumer_stream_close(stream);
 236 }
 237
 238 /*
 239  * Decrement the stream's channel refcount and if down to 0, return the channel
 240  * pointer so it can be destroyed by the caller or NULL if not.
 241  */
 242 static struct lttng_consumer_channel *unref_channel(
 243                 struct lttng_consumer_stream *stream)
 244 {
 245         struct lttng_consumer_channel *free_chan = NULL;
 246
 247         assert(stream);
 248         assert(stream->chan);
 249
 250         /* Update refcount of channel and see if we need to destroy it. */
 251         if (!uatomic_sub_return(&stream->chan->refcount, 1)
 252                         && !uatomic_read(&stream->chan->nb_init_stream_left)) {
 253                 free_chan = stream->chan;
 254         }
 255
 256         return free_chan;
 257 }
 258
 259 /*
 260  * Destroy a stream completely. This will delete, close and free the stream.
 261  * Once return, the stream is NO longer usable. Its channel may get destroyed
 262  * if conditions are met for a monitored stream.
 263  *
 264  * This MUST be called WITHOUT the consumer data and stream lock acquired if
 265  * the stream is in _monitor_ mode else it does not matter.
 266  */
 267 void consumer_stream_destroy(struct lttng_consumer_stream *stream,
 268                 struct lttng_ht *ht)
 269 {
 270         assert(stream);
 271
 272         /* Stream is in monitor mode. */
 273         if (stream->monitor) {
 274                 struct lttng_consumer_channel *free_chan = NULL;
 275
 276                 /*
 277                  * This means that the stream was successfully removed from the streams
 278                  * list of the channel and sent to the right thread managing this
 279                  * stream thus being globally visible.
 280                  */
 281                 if (stream->globally_visible) {
 282                         pthread_mutex_lock(&consumer_data.lock);
 283                         pthread_mutex_lock(&stream->chan->lock);
 284                         pthread_mutex_lock(&stream->lock);
 285                         /* Remove every reference of the stream in the consumer. */
 286                         consumer_stream_delete(stream, ht);
 287
 288                         destroy_close_stream(stream);
 289
 290                         /* Update channel's refcount of the stream. */
 291                         free_chan = unref_channel(stream);
 292
 293                         /* Indicates that the consumer data state MUST be updated after this. */
 294                         consumer_data.need_update = 1;
 295
 296                         pthread_mutex_unlock(&stream->lock);
 297                         pthread_mutex_unlock(&stream->chan->lock);
 298                         pthread_mutex_unlock(&consumer_data.lock);
 299                 } else {
 300                         /*
 301                          * If the stream is not visible globally, this needs to be done
 302                          * outside of the consumer data lock section.
 303                          */
 304                         free_chan = unref_channel(stream);
 305                 }
 306
 307                 if (free_chan) {
 308                         consumer_del_channel(free_chan);
 309                 }
 310         } else {
 311                 destroy_close_stream(stream);
 312         }
 313
 314         /* Free stream within a RCU call. */
 315         consumer_stream_free(stream);
 316 }