Fix: relayd leak on error in consumer splice()
[lttng-tools.git] / src / common / consumer.c
index b942778b32e9a768f7da0029507b52af10478804..e56afa78c78f020e6fc8d71a1d5b8a3c1a6ec5f6 100644 (file)
@@ -150,6 +150,31 @@ error:
        return (int) ret;
 }
 
+/*
+ * Cleanup the stream list of a channel. Those streams are not yet globally
+ * visible
+ */
+static void clean_channel_stream_list(struct lttng_consumer_channel *channel)
+{
+       struct lttng_consumer_stream *stream, *stmp;
+
+       assert(channel);
+
+       /* Delete streams that might have been left in the stream list. */
+       cds_list_for_each_entry_safe(stream, stmp, &channel->streams.head,
+                       send_node) {
+               cds_list_del(&stream->send_node);
+               /*
+                * Once a stream is added to this list, the buffers were created so we
+                * have a guarantee that this call will succeed. Setting the monitor
+                * mode to 0 so we don't lock nor try to delete the stream from the
+                * global hash table.
+                */
+               stream->monitor = 0;
+               consumer_stream_destroy(stream, NULL);
+       }
+}
+
 /*
  * Find a stream. The consumer_data.lock must be locked during this
  * call.
@@ -225,16 +250,6 @@ struct lttng_consumer_channel *consumer_find_channel(uint64_t key)
        return channel;
 }
 
-static void free_stream_rcu(struct rcu_head *head)
-{
-       struct lttng_ht_node_u64 *node =
-               caa_container_of(head, struct lttng_ht_node_u64, head);
-       struct lttng_consumer_stream *stream =
-               caa_container_of(node, struct lttng_consumer_stream, node);
-
-       free(stream);
-}
-
 static void free_channel_rcu(struct rcu_head *head)
 {
        struct lttng_ht_node_u64 *node =
@@ -302,23 +317,14 @@ void consumer_del_channel(struct lttng_consumer_channel *channel)
 {
        int ret;
        struct lttng_ht_iter iter;
-       struct lttng_consumer_stream *stream, *stmp;
 
        DBG("Consumer delete channel key %" PRIu64, channel->key);
 
        pthread_mutex_lock(&consumer_data.lock);
        pthread_mutex_lock(&channel->lock);
 
-       /* Delete streams that might have been left in the stream list. */
-       cds_list_for_each_entry_safe(stream, stmp, &channel->streams.head,
-                       send_node) {
-               cds_list_del(&stream->send_node);
-               /*
-                * Once a stream is added to this list, the buffers were created so
-                * we have a guarantee that this call will succeed.
-                */
-               consumer_stream_destroy(stream, NULL);
-       }
+       /* Destroy streams that might have been left in the stream list. */
+       clean_channel_stream_list(channel);
 
        if (channel->live_timer_enabled == 1) {
                consumer_timer_live_stop(channel);
@@ -1451,7 +1457,7 @@ ssize_t lttng_consumer_on_read_subbuffer_mmap(
 {
        unsigned long mmap_offset;
        void *mmap_base;
-       ssize_t ret = 0, written = 0;
+       ssize_t ret = 0;
        off_t orig_offset = stream->out_fd_offset;
        /* Default is on the disk */
        int outfd = stream->out_fd;
@@ -1475,9 +1481,9 @@ ssize_t lttng_consumer_on_read_subbuffer_mmap(
        case LTTNG_CONSUMER_KERNEL:
                mmap_base = stream->mmap_base;
                ret = kernctl_get_mmap_read_offset(stream->wait_fd, &mmap_offset);
-               if (ret != 0) {
+               if (ret < 0) {
+                       ret = -errno;
                        PERROR("tracer ctl get_mmap_read_offset");
-                       written = -errno;
                        goto end;
                }
                break;
@@ -1486,13 +1492,13 @@ ssize_t lttng_consumer_on_read_subbuffer_mmap(
                mmap_base = lttng_ustctl_get_mmap_base(stream);
                if (!mmap_base) {
                        ERR("read mmap get mmap base for stream %s", stream->name);
-                       written = -EPERM;
+                       ret = -EPERM;
                        goto end;
                }
                ret = lttng_ustctl_get_mmap_read_offset(stream, &mmap_offset);
                if (ret != 0) {
                        PERROR("tracer ctl get_mmap_read_offset");
-                       written = ret;
+                       ret = -EINVAL;
                        goto end;
                }
                break;
@@ -1516,30 +1522,20 @@ ssize_t lttng_consumer_on_read_subbuffer_mmap(
                }
 
                ret = write_relayd_stream_header(stream, netlen, padding, relayd);
-               if (ret >= 0) {
-                       /* Use the returned socket. */
-                       outfd = ret;
+               if (ret < 0) {
+                       relayd_hang_up = 1;
+                       goto write_error;
+               }
+               /* Use the returned socket. */
+               outfd = ret;
 
-                       /* Write metadata stream id before payload */
-                       if (stream->metadata_flag) {
-                               ret = write_relayd_metadata_id(outfd, stream, relayd, padding);
-                               if (ret < 0) {
-                                       written = ret;
-                                       /* Socket operation failed. We consider the relayd dead */
-                                       if (ret == -EPIPE || ret == -EINVAL) {
-                                               relayd_hang_up = 1;
-                                               goto write_error;
-                                       }
-                                       goto end;
-                               }
-                       }
-               } else {
-                       /* Socket operation failed. We consider the relayd dead */
-                       if (ret == -EPIPE || ret == -EINVAL) {
+               /* Write metadata stream id before payload */
+               if (stream->metadata_flag) {
+                       ret = write_relayd_metadata_id(outfd, stream, relayd, padding);
+                       if (ret < 0) {
                                relayd_hang_up = 1;
                                goto write_error;
                        }
-                       /* Else, use the default set before which is the filesystem. */
                }
        } else {
                /* No streaming, we have to set the len with the full padding */
@@ -1596,13 +1592,12 @@ ssize_t lttng_consumer_on_read_subbuffer_mmap(
                 * amount written.
                 */
                if (ret < 0) {
-                       written = -errno;
-               } else {
-                       written = ret;
+                       ret = -errno;
                }
+               relayd_hang_up = 1;
 
                /* Socket operation failed. We consider the relayd dead */
-               if (errno == EPIPE || errno == EINVAL) {
+               if (errno == EPIPE || errno == EINVAL || errno == EBADF) {
                        /*
                         * This is possible if the fd is closed on the other side
                         * (outfd) or any write problem. It can be verbose a bit for a
@@ -1610,16 +1605,13 @@ ssize_t lttng_consumer_on_read_subbuffer_mmap(
                         * abruptly. This can happen so set this to a DBG statement.
                         */
                        DBG("Consumer mmap write detected relayd hang up");
-                       relayd_hang_up = 1;
-                       goto write_error;
+               } else {
+                       /* Unhandled error, print it and stop function right now. */
+                       PERROR("Error in write mmap (ret %zd != len %lu)", ret, len);
                }
-
-               /* Unhandled error, print it and stop function right now. */
-               PERROR("Error in write mmap (ret %zd != len %lu)", ret, len);
-               goto end;
+               goto write_error;
        }
        stream->output_written += ret;
-       written = ret;
 
        /* This call is useless on a socket so better save a syscall. */
        if (!relayd) {
@@ -1646,7 +1638,7 @@ end:
        }
 
        rcu_read_unlock();
-       return written;
+       return ret;
 }
 
 /*
@@ -1691,7 +1683,7 @@ ssize_t lttng_consumer_on_read_subbuffer_splice(
        if (stream->net_seq_idx != (uint64_t) -1ULL) {
                relayd = consumer_find_relayd(stream->net_seq_idx);
                if (relayd == NULL) {
-                       ret = -EPIPE;
+                       written = -ret;
                        goto end;
                }
        }
@@ -1709,7 +1701,7 @@ ssize_t lttng_consumer_on_read_subbuffer_splice(
 
        /* Write metadata stream id before payload */
        if (relayd) {
-               int total_len = len;
+               unsigned long total_len = len;
 
                if (stream->metadata_flag) {
                        /*
@@ -1722,31 +1714,21 @@ ssize_t lttng_consumer_on_read_subbuffer_splice(
                                        padding);
                        if (ret < 0) {
                                written = ret;
-                               /* Socket operation failed. We consider the relayd dead */
-                               if (ret == -EBADF) {
-                                       WARN("Remote relayd disconnected. Stopping");
-                                       relayd_hang_up = 1;
-                                       goto write_error;
-                               }
-                               goto end;
+                               relayd_hang_up = 1;
+                               goto write_error;
                        }
 
                        total_len += sizeof(struct lttcomm_relayd_metadata_payload);
                }
 
                ret = write_relayd_stream_header(stream, total_len, padding, relayd);
-               if (ret >= 0) {
-                       /* Use the returned socket. */
-                       outfd = ret;
-               } else {
-                       /* Socket operation failed. We consider the relayd dead */
-                       if (ret == -EBADF) {
-                               WARN("Remote relayd disconnected. Stopping");
-                               relayd_hang_up = 1;
-                               goto write_error;
-                       }
-                       goto end;
+               if (ret < 0) {
+                       written = ret;
+                       relayd_hang_up = 1;
+                       goto write_error;
                }
+               /* Use the returned socket. */
+               outfd = ret;
        } else {
                /* No streaming, we have to set the len with the full padding */
                len += padding;
@@ -1763,6 +1745,7 @@ ssize_t lttng_consumer_on_read_subbuffer_splice(
                                        stream->out_fd, &(stream->tracefile_count_current),
                                        &stream->out_fd);
                        if (ret < 0) {
+                               written = ret;
                                ERR("Rotating output file");
                                goto end;
                        }
@@ -1774,6 +1757,7 @@ ssize_t lttng_consumer_on_read_subbuffer_splice(
                                                stream->chan->tracefile_size,
                                                stream->tracefile_count_current);
                                if (ret < 0) {
+                                       written = ret;
                                        goto end;
                                }
                                stream->index_fd = ret;
@@ -1796,28 +1780,24 @@ ssize_t lttng_consumer_on_read_subbuffer_splice(
                DBG("splice chan to pipe, ret %zd", ret_splice);
                if (ret_splice < 0) {
                        ret = errno;
-                       if (written == 0) {
-                               written = ret_splice;
-                       }
+                       written = -ret;
                        PERROR("Error in relay splice");
                        goto splice_error;
                }
 
                /* Handle stream on the relayd if the output is on the network */
-               if (relayd) {
-                       if (stream->metadata_flag) {
-                               size_t metadata_payload_size =
-                                       sizeof(struct lttcomm_relayd_metadata_payload);
+               if (relayd && stream->metadata_flag) {
+                       size_t metadata_payload_size =
+                               sizeof(struct lttcomm_relayd_metadata_payload);
 
-                               /* Update counter to fit the spliced data */
-                               ret_splice += metadata_payload_size;
-                               len += metadata_payload_size;
-                               /*
-                                * We do this so the return value can match the len passed as
-                                * argument to this function.
-                                */
-                               written -= metadata_payload_size;
-                       }
+                       /* Update counter to fit the spliced data */
+                       ret_splice += metadata_payload_size;
+                       len += metadata_payload_size;
+                       /*
+                        * We do this so the return value can match the len passed as
+                        * argument to this function.
+                        */
+                       written -= metadata_payload_size;
                }
 
                /* Splice data out */
@@ -1826,24 +1806,16 @@ ssize_t lttng_consumer_on_read_subbuffer_splice(
                DBG("Consumer splice pipe to file, ret %zd", ret_splice);
                if (ret_splice < 0) {
                        ret = errno;
-                       if (written == 0) {
-                               written = ret_splice;
-                       }
-                       /* Socket operation failed. We consider the relayd dead */
-                       if (errno == EBADF || errno == EPIPE || errno == ESPIPE) {
-                               WARN("Remote relayd disconnected. Stopping");
-                               relayd_hang_up = 1;
-                               goto write_error;
-                       }
-                       PERROR("Error in file splice");
-                       goto splice_error;
+                       written = -ret;
+                       relayd_hang_up = 1;
+                       goto write_error;
                } else if (ret_splice > len) {
                        /*
                         * We don't expect this code path to be executed but you never know
                         * so this is an extra protection agains a buggy splice().
                         */
-                       written += ret_splice;
                        ret = errno;
+                       written += ret_splice;
                        PERROR("Wrote more data than requested %zd (len: %lu)", ret_splice,
                                        len);
                        goto splice_error;
@@ -1956,7 +1928,7 @@ int lttng_consumer_recv_cmd(struct lttng_consumer_local_data *ctx,
        }
 }
 
-void lttng_consumer_close_metadata(void)
+void lttng_consumer_close_all_metadata(void)
 {
        switch (consumer_data.type) {
        case LTTNG_CONSUMER_KERNEL:
@@ -1974,7 +1946,7 @@ void lttng_consumer_close_metadata(void)
                 * because at this point we are sure that the metadata producer is
                 * either dead or blocked.
                 */
-               lttng_ustconsumer_close_metadata(metadata_ht);
+               lttng_ustconsumer_close_all_metadata(metadata_ht);
                break;
        default:
                ERR("Unknown consumer_data type");
@@ -1988,10 +1960,7 @@ void lttng_consumer_close_metadata(void)
 void consumer_del_metadata_stream(struct lttng_consumer_stream *stream,
                struct lttng_ht *ht)
 {
-       int ret;
-       struct lttng_ht_iter iter;
        struct lttng_consumer_channel *free_chan = NULL;
-       struct consumer_relayd_sock_pair *relayd;
 
        assert(stream);
        /*
@@ -2002,96 +1971,17 @@ void consumer_del_metadata_stream(struct lttng_consumer_stream *stream,
 
        DBG3("Consumer delete metadata stream %d", stream->wait_fd);
 
-       if (ht == NULL) {
-               /* Means the stream was allocated but not successfully added */
-               goto free_stream_rcu;
-       }
-
        pthread_mutex_lock(&consumer_data.lock);
        pthread_mutex_lock(&stream->chan->lock);
        pthread_mutex_lock(&stream->lock);
 
-       switch (consumer_data.type) {
-       case LTTNG_CONSUMER_KERNEL:
-               if (stream->mmap_base != NULL) {
-                       ret = munmap(stream->mmap_base, stream->mmap_len);
-                       if (ret != 0) {
-                               PERROR("munmap metadata stream");
-                       }
-               }
-               if (stream->wait_fd >= 0) {
-                       ret = close(stream->wait_fd);
-                       if (ret < 0) {
-                               PERROR("close kernel metadata wait_fd");
-                       }
-               }
-               break;
-       case LTTNG_CONSUMER32_UST:
-       case LTTNG_CONSUMER64_UST:
-               if (stream->monitor) {
-                       /* close the write-side in close_metadata */
-                       ret = close(stream->ust_metadata_poll_pipe[0]);
-                       if (ret < 0) {
-                               PERROR("Close UST metadata read-side poll pipe");
-                       }
-               }
-               lttng_ustconsumer_del_stream(stream);
-               break;
-       default:
-               ERR("Unknown consumer_data type");
-               assert(0);
-               goto end;
-       }
+       /* Remove any reference to that stream. */
+       consumer_stream_delete(stream, ht);
 
-       rcu_read_lock();
-       iter.iter.node = &stream->node.node;
-       ret = lttng_ht_del(ht, &iter);
-       assert(!ret);
-
-       iter.iter.node = &stream->node_channel_id.node;
-       ret = lttng_ht_del(consumer_data.stream_per_chan_id_ht, &iter);
-       assert(!ret);
-
-       iter.iter.node = &stream->node_session_id.node;
-       ret = lttng_ht_del(consumer_data.stream_list_ht, &iter);
-       assert(!ret);
-       rcu_read_unlock();
-
-       if (stream->out_fd >= 0) {
-               ret = close(stream->out_fd);
-               if (ret) {
-                       PERROR("close");
-               }
-       }
-
-       /* Check and cleanup relayd */
-       rcu_read_lock();
-       relayd = consumer_find_relayd(stream->net_seq_idx);
-       if (relayd != NULL) {
-               uatomic_dec(&relayd->refcount);
-               assert(uatomic_read(&relayd->refcount) >= 0);
-
-               /* Closing streams requires to lock the control socket. */
-               pthread_mutex_lock(&relayd->ctrl_sock_mutex);
-               ret = relayd_send_close_stream(&relayd->control_sock,
-                               stream->relayd_stream_id, stream->next_net_seq_num - 1);
-               pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
-               if (ret < 0) {
-                       DBG("Unable to close stream on the relayd. Continuing");
-                       /*
-                        * Continue here. There is nothing we can do for the relayd.
-                        * Chances are that the relayd has closed the socket so we just
-                        * continue cleaning up.
-                        */
-               }
-
-               /* Both conditions are met, we destroy the relayd. */
-               if (uatomic_read(&relayd->refcount) == 0 &&
-                               uatomic_read(&relayd->destroy_flag)) {
-                       consumer_destroy_relayd(relayd);
-               }
-       }
-       rcu_read_unlock();
+       /* Close down everything including the relayd if one. */
+       consumer_stream_close(stream);
+       /* Destroy tracer buffers of the stream. */
+       consumer_stream_destroy_buffers(stream);
 
        /* Atomically decrement channel refcount since other threads can use it. */
        if (!uatomic_sub_return(&stream->chan->refcount, 1)
@@ -2100,11 +1990,10 @@ void consumer_del_metadata_stream(struct lttng_consumer_stream *stream,
                free_chan = stream->chan;
        }
 
-end:
        /*
         * Nullify the stream reference so it is not used after deletion. The
-        * channel lock MUST be acquired before being able to check for
-        * a NULL pointer value.
+        * channel lock MUST be acquired before being able to check for a NULL
+        * pointer value.
         */
        stream->chan->metadata_stream = NULL;
 
@@ -2116,8 +2005,7 @@ end:
                consumer_del_channel(free_chan);
        }
 
-free_stream_rcu:
-       call_rcu(&stream->node.head, free_stream_rcu);
+       consumer_stream_free(stream);
 }
 
 /*
@@ -2354,7 +2242,7 @@ restart:
 
                                        /* Add metadata stream to the global poll events list */
                                        lttng_poll_add(&events, stream->wait_fd,
-                                                       LPOLLIN | LPOLLPRI);
+                                                       LPOLLIN | LPOLLPRI | LPOLLHUP);
                                }
 
                                /* Handle other stream */
@@ -2746,12 +2634,17 @@ void consumer_close_channel_streams(struct lttng_consumer_channel *channel)
                        break;
                case LTTNG_CONSUMER32_UST:
                case LTTNG_CONSUMER64_UST:
-                       /*
-                        * Note: a mutex is taken internally within
-                        * liblttng-ust-ctl to protect timer wakeup_fd
-                        * use from concurrent close.
-                        */
-                       lttng_ustconsumer_close_stream_wakeup(stream);
+                       if (stream->metadata_flag) {
+                               /* Safe and protected by the stream lock. */
+                               lttng_ustconsumer_close_metadata(stream->chan);
+                       } else {
+                               /*
+                                * Note: a mutex is taken internally within
+                                * liblttng-ust-ctl to protect timer wakeup_fd
+                                * use from concurrent close.
+                                */
+                               lttng_ustconsumer_close_stream_wakeup(stream);
+                       }
                        break;
                default:
                        ERR("Unknown consumer_data type");
@@ -2906,7 +2799,14 @@ restart:
                                                break;
                                        case CONSUMER_CHANNEL_DEL:
                                        {
-                                               struct lttng_consumer_stream *stream, *stmp;
+                                               /*
+                                                * This command should never be called if the channel
+                                                * has streams monitored by either the data or metadata
+                                                * thread. The consumer only notify this thread with a
+                                                * channel del. command if it receives a destroy
+                                                * channel command from the session daemon that send it
+                                                * if a command prior to the GET_CHANNEL failed.
+                                                */
 
                                                rcu_read_lock();
                                                chan = consumer_find_channel(key);
@@ -2919,24 +2819,15 @@ restart:
                                                iter.iter.node = &chan->wait_fd_node.node;
                                                ret = lttng_ht_del(channel_ht, &iter);
                                                assert(ret == 0);
-                                               consumer_close_channel_streams(chan);
 
                                                switch (consumer_data.type) {
                                                case LTTNG_CONSUMER_KERNEL:
                                                        break;
                                                case LTTNG_CONSUMER32_UST:
                                                case LTTNG_CONSUMER64_UST:
-                                                       /* Delete streams that might have been left in the stream list. */
-                                                       cds_list_for_each_entry_safe(stream, stmp, &chan->streams.head,
-                                                                       send_node) {
-                                                               health_code_update();
-
-                                                               cds_list_del(&stream->send_node);
-                                                               lttng_ustconsumer_del_stream(stream);
-                                                               uatomic_sub(&stream->chan->refcount, 1);
-                                                               assert(&chan->refcount);
-                                                               free(stream);
-                                                       }
+                                                       health_code_update();
+                                                       /* Destroy streams that might have been left in the stream list. */
+                                                       clean_channel_stream_list(chan);
                                                        break;
                                                default:
                                                        ERR("Unknown consumer_data type");
@@ -2989,6 +2880,12 @@ restart:
                                lttng_poll_del(&events, chan->wait_fd);
                                ret = lttng_ht_del(channel_ht, &iter);
                                assert(ret == 0);
+
+                               /*
+                                * This will close the wait fd for each stream associated to
+                                * this channel AND monitored by the data/metadata thread thus
+                                * will be clean by the right thread.
+                                */
                                consumer_close_channel_streams(chan);
 
                                /* Release our own refcount */
@@ -3174,7 +3071,7 @@ end:
         *
         * NOTE: for now, this only applies to the UST tracer.
         */
-       lttng_consumer_close_metadata();
+       lttng_consumer_close_all_metadata();
 
        /*
         * when all fds have hung up, the polling thread
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