Fix --disable-lttng-ust build after UST API update

[lttng-tools.git] / liblttng-ustconsumer / lttng-ustconsumer.c

diff --git a/liblttng-ustconsumer/lttng-ustconsumer.c b/liblttng-ustconsumer/lttng-ustconsumer.c
index f938d3548d9e8ed4ef049333efe1fc1aa16d1a0c..89dbefa361380ad2c317bf161a6d65cc7baae0e5 100644 (file)
--- a/liblttng-ustconsumer/lttng-ustconsumer.c
+++ b/liblttng-ustconsumer/lttng-ustconsumer.c
@@ -287,6 +287,7 @@ int lttng_ustconsumer_allocate_channel(struct lttng_consumer_channel *chan)
 void lttng_ustconsumer_on_stream_hangup(struct lttng_consumer_stream *stream)
 {
        ustctl_flush_buffer(stream->chan->handle, stream->buf, 0);
+       stream->hangup_flush_done = 1;
 }
 
 void lttng_ustconsumer_del_channel(struct lttng_consumer_channel *chan)
@@ -343,12 +344,14 @@ int lttng_ustconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
                stream->wait_fd, stream->key);
 
        /* We can consume the 1 byte written into the wait_fd by UST */
-       do {
-               readlen = read(stream->wait_fd, &dummy, 1);
-       } while (readlen == -1 && errno == -EINTR);
-       if (readlen == -1) {
-               ret = readlen;
-               goto end;
+       if (!stream->hangup_flush_done) {
+               do {
+                       readlen = read(stream->wait_fd, &dummy, 1);
+               } while (readlen == -1 && errno == -EINTR);
+               if (readlen == -1) {
+                       ret = readlen;
+                       goto end;
+               }
        }
 
        buf = stream->buf;
@@ -356,7 +359,7 @@ int lttng_ustconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
        /* Get the next subbuffer */
        err = ustctl_get_next_subbuf(handle, buf);
        if (err != 0) {
-               ret = errno;
+               ret = -ret;     /* ustctl_get_next_subbuf returns negative, caller expect positive. */
                /*
                 * This is a debug message even for single-threaded consumer,
                 * because poll() have more relaxed criterions than get subbuf,
@@ -370,11 +373,7 @@ int lttng_ustconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
        assert(stream->output == LTTNG_EVENT_MMAP);
        /* read the used subbuffer size */
        err = ustctl_get_padded_subbuf_size(handle, buf, &len);
-       if (err != 0) {
-               ret = errno;
-               perror("Getting sub-buffer len failed.");
-               goto end;
-       }
+       assert(err == 0);
        /* write the subbuffer to the tracefile */
        ret = lttng_consumer_on_read_subbuffer_mmap(ctx, stream, len);
        if (ret < 0) {
@@ -385,16 +384,7 @@ int lttng_ustconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
                ERR("Error writing to tracefile");
        }
        err = ustctl_put_next_subbuf(handle, buf);
-       if (err != 0) {
-               ret = errno;
-               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.");
-               }
-               goto end;
-       }
+       assert(err == 0);
 end:
        return ret;
 }