Fix: Returned error code in consumer on read buffer

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

diff --git a/src/common/kernel-consumer/kernel-consumer.c b/src/common/kernel-consumer/kernel-consumer.c
index 47463c6501eddb48c4963d99c15b3d3c510c035c..fe93c2e21feed3f63c3f2def9d6af91cdd65ac4a 100644 (file)
--- a/src/common/kernel-consumer/kernel-consumer.c
+++ b/src/common/kernel-consumer/kernel-consumer.c
@@ -171,6 +171,15 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                        goto end_nosignal;
                }
 
+               /*
+                * The buffer flush is done on the session daemon side for the kernel
+                * so no need for the stream "hangup_flush_done" variable to be
+                * tracked. This is important for a kernel stream since we don't rely
+                * on the flush state of the stream to read data. It's not the case for
+                * user space tracing.
+                */
+               new_stream->hangup_flush_done = 0;
+
                /* The stream is not metadata. Get relayd reference if exists. */
                relayd = consumer_find_relayd(msg.u.stream.net_index);
                if (relayd != NULL) {
@@ -190,14 +199,29 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
                        goto end_nosignal;
                }
 
-               if (ctx->on_recv_stream != NULL) {
-                       ret = ctx->on_recv_stream(new_stream);
-                       if (ret == 0) {
-                               consumer_add_stream(new_stream);
-                       } else if (ret < 0) {
-                               goto end_nosignal;
+               /* Send stream to the metadata thread */
+               if (new_stream->metadata_flag) {
+                       if (ctx->on_recv_stream) {
+                               ret = ctx->on_recv_stream(new_stream);
+                               if (ret < 0) {
+                                       goto end_nosignal;
+                               }
+                       }
+
+                       do {
+                               ret = write(ctx->consumer_metadata_pipe[1], new_stream,
+                                               sizeof(struct lttng_consumer_stream));
+                       } while (ret < 0 && errno == EINTR);
+                       if (ret < 0) {
+                               PERROR("write metadata pipe");
                        }
                } else {
+                       if (ctx->on_recv_stream) {
+                               ret = ctx->on_recv_stream(new_stream);
+                               if (ret < 0) {
+                                       goto end_nosignal;
+                               }
+                       }
                        consumer_add_stream(new_stream);
                }
 
@@ -280,6 +304,7 @@ ssize_t lttng_kconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
        /* Get the next subbuffer */
        err = kernctl_get_next_subbuf(infd);
        if (err != 0) {
+               ret = -err;
                /*
                 * This is a debug message even for single-threaded consumer,
                 * because poll() have more relaxed criterions than get subbuf,
@@ -296,8 +321,9 @@ ssize_t lttng_kconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
                        /* read the whole subbuffer */
                        err = kernctl_get_padded_subbuf_size(infd, &len);
                        if (err != 0) {
-                               errno = -ret;
+                               errno = -err;
                                perror("Getting sub-buffer len failed.");
+                               ret = -err;
                                goto end;
                        }
 
@@ -317,8 +343,9 @@ ssize_t lttng_kconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
                        /* read the used subbuffer size */
                        err = kernctl_get_padded_subbuf_size(infd, &len);
                        if (err != 0) {
-                               errno = -ret;
+                               errno = -err;
                                perror("Getting sub-buffer len failed.");
+                               ret = -err;
                                goto end;
                        }
                        /* write the subbuffer to the tracefile */
@@ -338,13 +365,15 @@ ssize_t lttng_kconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
 
        err = kernctl_put_next_subbuf(infd);
        if (err != 0) {
-               errno = -ret;
+               errno = -err;
                if (errno == EFAULT) {
                        perror("Error in unreserving sub buffer\n");
                } else if (errno == EIO) {
                        /* Should never happen with newer LTTng versions */
                        perror("Reader has been pushed by the writer, last sub-buffer corrupted.");
                }
+
+               ret = -err;
                goto end;
        }