Fix: compare write() return value to size

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

diff --git a/src/common/consumer.c b/src/common/consumer.c
index 16521a8b863788fd957b756d7c4882f6b3c5abbd..1e710ab3d9b80fefbbfe2aad58fd050e50d03444 100644 (file)
--- a/src/common/consumer.c
+++ b/src/common/consumer.c
@@ -782,6 +782,13 @@ static int write_relayd_stream_header(struct lttng_consumer_stream *stream,
                data_hdr.stream_id = htobe64(stream->relayd_stream_id);
                data_hdr.data_size = htobe32(data_size);
                data_hdr.padding_size = htobe32(padding);
+               /*
+                * Note that net_seq_num below is assigned with the *current* value of
+                * next_net_seq_num and only after that the next_net_seq_num will be
+                * increment. This is why when issuing a command on the relayd using
+                * this next value, 1 should always be substracted in order to compare
+                * the last seen sequence number on the relayd side to the last sent.
+                */
                data_hdr.net_seq_num = htobe64(stream->next_net_seq_num++);
                /* Other fields are zeroed previously */
 
@@ -1099,7 +1106,7 @@ void lttng_consumer_should_exit(struct lttng_consumer_local_data *ctx)
        do {
                ret = write(ctx->consumer_should_quit[1], "4", 1);
        } while (ret < 0 && errno == EINTR);
-       if (ret < 0) {
+       if (ret < 0 || ret != 1) {
                PERROR("write consumer quit");
        }
 
@@ -1317,8 +1324,16 @@ static int write_relayd_metadata_id(int fd,
        do {
                ret = write(fd, (void *) &hdr, sizeof(hdr));
        } while (ret < 0 && errno == EINTR);
-       if (ret < 0) {
-               PERROR("write metadata stream id");
+       if (ret < 0 || ret != sizeof(hdr)) {
+               /*
+                * This error means that the fd's end is closed so ignore the perror
+                * not to clubber the error output since this can happen in a normal
+                * code path.
+                */
+               if (errno != EPIPE) {
+                       PERROR("write metadata stream id");
+               }
+               DBG3("Consumer failed to write relayd metadata id (errno: %d)", errno);
                goto end;
        }
        DBG("Metadata stream id %" PRIu64 " with padding %lu written before data",
@@ -1435,7 +1450,13 @@ ssize_t lttng_consumer_on_read_subbuffer_mmap(
                } while (ret < 0 && errno == EINTR);
                DBG("Consumer mmap write() ret %zd (len %lu)", ret, len);
                if (ret < 0) {
-                       PERROR("Error in file write");
+                       /*
+                        * 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 normal
+                        * execution if for instance the relayd is stopped abruptly. This
+                        * can happen so set this to a DBG statement.
+                        */
+                       DBG("Error in file write mmap");
                        if (written == 0) {
                                written = ret;
                        }
@@ -2101,17 +2122,13 @@ void *consumer_thread_metadata_poll(void *data)
        DBG("Metadata main loop started");
 
        while (1) {
-               lttng_poll_reset(&events);
-
-               nb_fd = LTTNG_POLL_GETNB(&events);
-
                /* Only the metadata pipe is set */
-               if (nb_fd == 0 && consumer_quit == 1) {
+               if (LTTNG_POLL_GETNB(&events) == 0 && consumer_quit == 1) {
                        goto end;
                }
 
 restart:
-               DBG("Metadata poll wait with %d fd(s)", nb_fd);
+               DBG("Metadata poll wait with %d fd(s)", LTTNG_POLL_GETNB(&events));
                ret = lttng_poll_wait(&events, -1);
                DBG("Metadata event catched in thread");
                if (ret < 0) {
@@ -2122,6 +2139,8 @@ restart:
                        goto error;
                }
 
+               nb_fd = ret;
+
                /* From here, the event is a metadata wait fd */
                for (i = 0; i < nb_fd; i++) {
                        revents = LTTNG_POLL_GETEV(&events, i);
@@ -2366,6 +2385,11 @@ void *consumer_thread_data_poll(void *data)
                                pipe_readlen = read(ctx->consumer_data_pipe[0], &new_stream,
                                                sizeof(new_stream));
                        } while (pipe_readlen == -1 && errno == EINTR);
+                       if (pipe_readlen < 0) {
+                               PERROR("read consumer data pipe");
+                               /* Continue so we can at least handle the current stream(s). */
+                               continue;
+                       }
 
                        /*
                         * If the stream is NULL, just ignore it. It's also possible that
@@ -3008,10 +3032,12 @@ int consumer_data_pending(uint64_t id)
                if (relayd) {
                        pthread_mutex_lock(&relayd->ctrl_sock_mutex);
                        if (stream->metadata_flag) {
-                               ret = relayd_quiescent_control(&relayd->control_sock);
+                               ret = relayd_quiescent_control(&relayd->control_sock,
+                                               stream->relayd_stream_id);
                        } else {
                                ret = relayd_data_pending(&relayd->control_sock,
-                                               stream->relayd_stream_id, stream->next_net_seq_num);
+                                               stream->relayd_stream_id,
+                                               stream->next_net_seq_num - 1);
                        }
                        pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
                        if (ret == 1) {
@@ -3030,10 +3056,12 @@ int consumer_data_pending(uint64_t id)
                ret = relayd_end_data_pending(&relayd->control_sock,
                                relayd->relayd_session_id, &is_data_inflight);
                pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
-               if (ret < 0 || !is_data_inflight) {
-                       /* On error or if NO data inflight, no data is pending. */
+               if (ret < 0) {
                        goto data_not_pending;
                }
+               if (is_data_inflight) {
+                       goto data_pending;
+               }
        }
 
        /*