Fix: consumer data pending for empty streams

[lttng-tools.git] / src / common / consumer.c

diff --git a/src/common/consumer.c b/src/common/consumer.c
index 4b657f33249f7a4f777b7b3ff784b379b15f5878..7acb8560ca4e07bfdccc89518477dad6a8d79051 100644 (file)
--- a/src/common/consumer.c
+++ b/src/common/consumer.c
@@ -498,6 +498,7 @@ struct lttng_consumer_stream *consumer_allocate_stream(uint64_t channel_key,
        stream->key = stream_key;
        stream->out_fd = -1;
        stream->out_fd_offset = 0;
+       stream->output_written = 0;
        stream->state = state;
        stream->uid = uid;
        stream->gid = gid;
@@ -1334,6 +1335,7 @@ ssize_t lttng_consumer_on_read_subbuffer_mmap(
        if (stream->net_seq_idx != (uint64_t) -1ULL) {
                relayd = consumer_find_relayd(stream->net_seq_idx);
                if (relayd == NULL) {
+                       ret = -EPIPE;
                        goto end;
                }
        }
@@ -1343,28 +1345,31 @@ 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) {
+                       PERROR("tracer ctl get_mmap_read_offset");
+                       written = -errno;
+                       goto end;
+               }
                break;
        case LTTNG_CONSUMER32_UST:
        case LTTNG_CONSUMER64_UST:
                mmap_base = lttng_ustctl_get_mmap_base(stream);
                if (!mmap_base) {
                        ERR("read mmap get mmap base for stream %s", stream->name);
-                       written = -1;
+                       written = -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;
+                       goto end;
+               }
                break;
        default:
                ERR("Unknown consumer_data type");
                assert(0);
        }
-       if (ret != 0) {
-               errno = -ret;
-               PERROR("tracer ctl get_mmap_read_offset");
-               written = ret;
-               goto end;
-       }
 
        /* Handle stream on the relayd if the output is on the network */
        if (relayd) {
@@ -1427,6 +1432,8 @@ ssize_t lttng_consumer_on_read_subbuffer_mmap(
                        outfd = stream->out_fd = ret;
                        /* Reset current size because we just perform a rotation. */
                        stream->tracefile_size_current = 0;
+                       stream->out_fd_offset = 0;
+                       orig_offset = 0;
                }
                stream->tracefile_size_current += len;
        }
@@ -1445,7 +1452,7 @@ ssize_t lttng_consumer_on_read_subbuffer_mmap(
                         */
                        DBG("Error in file write mmap");
                        if (written == 0) {
-                               written = ret;
+                               written = -errno;
                        }
                        /* Socket operation failed. We consider the relayd dead */
                        if (errno == EPIPE || errno == EINVAL) {
@@ -1469,6 +1476,7 @@ ssize_t lttng_consumer_on_read_subbuffer_mmap(
                                        SYNC_FILE_RANGE_WRITE);
                        stream->out_fd_offset += ret;
                }
+               stream->output_written += ret;
                written += ret;
        }
        lttng_consumer_sync_trace_file(stream, orig_offset);
@@ -1533,6 +1541,7 @@ 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;
                        goto end;
                }
        }
@@ -1609,6 +1618,8 @@ ssize_t lttng_consumer_on_read_subbuffer_splice(
                        outfd = stream->out_fd = ret;
                        /* Reset current size because we just perform a rotation. */
                        stream->tracefile_size_current = 0;
+                       stream->out_fd_offset = 0;
+                       orig_offset = 0;
                }
                stream->tracefile_size_current += len;
        }
@@ -1679,6 +1690,7 @@ ssize_t lttng_consumer_on_read_subbuffer_splice(
                                        SYNC_FILE_RANGE_WRITE);
                        stream->out_fd_offset += ret_splice;
                }
+               stream->output_written += ret_splice;
                written += ret_splice;
        }
        lttng_consumer_sync_trace_file(stream, orig_offset);
@@ -3391,6 +3403,15 @@ int consumer_data_pending(uint64_t id)
                 */
                ret = cds_lfht_is_node_deleted(&stream->node.node);
                if (!ret) {
+                       /*
+                        * An empty output file is not valid. We need at least one packet
+                        * generated per stream, even if it contains no event, so it
+                        * contains at least one packet header.
+                        */
+                       if (stream->output_written == 0) {
+                               pthread_mutex_unlock(&stream->lock);
+                               goto data_pending;
+                       }
                        /* Check the stream if there is data in the buffers. */
                        ret = data_pending(stream);
                        if (ret == 1) {