Cygwin: Fix handling of wait pipe hangup by properly detecting EOF

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

diff --git a/src/common/ust-consumer/ust-consumer.c b/src/common/ust-consumer/ust-consumer.c
index 97b890bf25340ba885f65a5c394d74de187126dd..9d624966bf6ae76f942401c5c9b8b1205bdaef54 100644 (file)
--- a/src/common/ust-consumer/ust-consumer.c
+++ b/src/common/ust-consumer/ust-consumer.c
@@ -414,6 +414,31 @@ void lttng_ustconsumer_del_stream(struct lttng_consumer_stream *stream)
 }
 
 
+int lttng_ustconsumer_check_pipe(struct lttng_consumer_stream *stream,
+               struct lttng_consumer_local_data *ctx)
+{
+       ssize_t readlen;
+       char dummy;
+
+       DBG("In check_pipe (wait_fd: %d, stream key: %d)\n",
+               stream->wait_fd, stream->key);
+
+       /* We consume the 1 byte written into the wait_fd by UST */
+       if (!stream->hangup_flush_done) {
+               do {
+                       readlen = read(stream->wait_fd, &dummy, 1);
+               } while (readlen == -1 && errno == EINTR);
+               if (readlen == -1) {
+                       return -1;      /* error */
+               }
+               DBG("Read %zu byte from pipe: %c\n", readlen, dummy);
+               if (readlen == 0)
+                       return 1;       /* POLLHUP */
+       }
+       return 0;       /* no error nor HUP */
+
+}
+
 int lttng_ustconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
                struct lttng_consumer_local_data *ctx)
 {
@@ -437,6 +462,7 @@ int lttng_ustconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
                        ret = readlen;
                        goto end;
                }
+               DBG("Read %zu byte from pipe: %c\n", readlen, dummy);
        }
 
        buf = stream->buf;