Use case-scope error labels when handling LTTNG_CONSUMER_ADD_STREAM
authorJérémie Galarneau <jeremie.galarneau@efficios.com>
Tue, 27 Aug 2019 20:19:34 +0000 (16:19 -0400)
committerJérémie Galarneau <jeremie.galarneau@efficios.com>
Wed, 28 Aug 2019 22:33:19 +0000 (18:33 -0400)
This cleans-up the error handling of the case handling the
LTTNG_CONSUMER_ADD_STREAM command. This is done in order to allow a
follow-up commit to perform some common clean-up operations on error
while introducing as few changes as possible.

No behaviour change is intended beyond additional calls to
health_code_update() in some code paths which should have no impact.

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
src/common/kernel-consumer/kernel-consumer.c

index 9742ea0844d79d5b64a1e9888d7b8bb54217c332..d6fdb036a5e9b50ac97ba5fbd17c735776e252d1 100644 (file)
@@ -591,14 +591,14 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                ret = consumer_send_status_msg(sock, ret_code);
                if (ret < 0) {
                        /* Somehow, the session daemon is not responding anymore. */
-                       goto error_fatal;
+                       goto error_add_stream_fatal;
                }
 
                health_code_update();
 
                if (ret_code != LTTCOMM_CONSUMERD_SUCCESS) {
                        /* Channel was not found. */
-                       goto end_nosignal;
+                       goto error_add_stream_nosignal;
                }
 
                /* Blocking call */
@@ -606,7 +606,7 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                ret = lttng_consumer_poll_socket(consumer_sockpoll);
                health_poll_exit();
                if (ret) {
-                       goto error_fatal;
+                       goto error_add_stream_fatal;
                }
 
                health_code_update();
@@ -615,8 +615,7 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                ret = lttcomm_recv_fds_unix_sock(sock, &fd, 1);
                if (ret != sizeof(fd)) {
                        lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_FD);
-                       rcu_read_unlock();
-                       return ret;
+                       goto end;
                }
 
                health_code_update();
@@ -629,7 +628,7 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                ret = consumer_send_status_msg(sock, ret_code);
                if (ret < 0) {
                        /* Somehow, the session daemon is not responding anymore. */
-                       goto end_nosignal;
+                       goto error_add_stream_nosignal;
                }
 
                health_code_update();
@@ -654,7 +653,7 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                                break;
                        }
                        pthread_mutex_unlock(&channel->lock);
-                       goto end_nosignal;
+                       goto error_add_stream_nosignal;
                }
 
                new_stream->chan = channel;
@@ -664,7 +663,7 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                if (ret < 0) {
                        pthread_mutex_unlock(&channel->lock);
                        ERR("Failed to get kernel maximal subbuffer size");
-                       goto end_nosignal;
+                       goto error_add_stream_nosignal;
                }
 
                consumer_stream_update_channel_attributes(new_stream,
@@ -675,7 +674,7 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                        ret = utils_create_pipe(new_stream->splice_pipe);
                        if (ret < 0) {
                                pthread_mutex_unlock(&channel->lock);
-                               goto end_nosignal;
+                               goto error_add_stream_nosignal;
                        }
                        break;
                case CONSUMER_CHANNEL_MMAP:
@@ -684,7 +683,7 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                default:
                        ERR("Stream output unknown %d", channel->output);
                        pthread_mutex_unlock(&channel->lock);
-                       goto end_nosignal;
+                       goto error_add_stream_nosignal;
                }
 
                /*
@@ -716,7 +715,7 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                                pthread_mutex_unlock(&new_stream->lock);
                                pthread_mutex_unlock(&channel->lock);
                                consumer_stream_free(new_stream);
-                               goto end_nosignal;
+                               goto error_add_stream_nosignal;
                        }
                }
                health_code_update();
@@ -733,7 +732,7 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                        cds_list_add(&new_stream->send_node, &channel->streams.head);
                        pthread_mutex_unlock(&new_stream->lock);
                        pthread_mutex_unlock(&channel->lock);
-                       break;
+                       goto end_add_stream;
                }
 
                /* Send stream to relayd if the stream has an ID. */
@@ -744,7 +743,7 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                                pthread_mutex_unlock(&new_stream->lock);
                                pthread_mutex_unlock(&channel->lock);
                                consumer_stream_free(new_stream);
-                               goto end_nosignal;
+                               goto error_add_stream_nosignal;
                        }
 
                        /*
@@ -758,7 +757,7 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                                if (ret < 0) {
                                        pthread_mutex_unlock(&new_stream->lock);
                                        pthread_mutex_unlock(&channel->lock);
-                                       goto end_nosignal;
+                                       goto error_add_stream_nosignal;
                                }
                        }
                }
@@ -789,12 +788,17 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                        } else {
                                consumer_del_stream_for_data(new_stream);
                        }
-                       goto end_nosignal;
+                       goto error_add_stream_nosignal;
                }
 
                DBG("Kernel consumer ADD_STREAM %s (fd: %d) %s with relayd id %" PRIu64,
                                new_stream->name, fd, new_stream->chan->pathname, new_stream->relayd_stream_id);
+end_add_stream:
                break;
+error_add_stream_nosignal:
+               goto end_nosignal;
+error_add_stream_fatal:
+               goto error_fatal;
        }
        case LTTNG_CONSUMER_STREAMS_SENT:
        {
@@ -1272,15 +1276,16 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
        }
 
 end_nosignal:
-       rcu_read_unlock();
-
        /*
         * Return 1 to indicate success since the 0 value can be a socket
         * shutdown during the recv() or send() call.
         */
-       health_code_update();
-       return 1;
-
+       ret = 1;
+       goto end;
+error_fatal:
+       /* This will issue a consumer stop. */
+       ret = -1;
+       goto end;
 end_msg_sessiond:
        /*
         * The returned value here is not useful since either way we'll return 1 to
@@ -1291,16 +1296,11 @@ end_msg_sessiond:
        if (ret < 0) {
                goto error_fatal;
        }
-       rcu_read_unlock();
-
+       ret = 1;
+end:
        health_code_update();
-
-       return 1;
-
-error_fatal:
        rcu_read_unlock();
-       /* This will issue a consumer stop. */
-       return -1;
+       return ret;
 }
 
 /*
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