X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fcommon%2Fkernel-consumer%2Fkernel-consumer.c;h=0b0592adb8a3bbe008141a4cb92196e020b752c8;hp=2456d3fc91936c69f074bbd038ee227c46e48220;hb=7c5aef6226a4752f3a4e60cd0b52c741dced395e;hpb=536322299f7fc9ef136a0d7e50ba8e1b5d7a754b

diff --git a/src/common/kernel-consumer/kernel-consumer.c b/src/common/kernel-consumer/kernel-consumer.c
index 2456d3fc9..0b0592adb 100644
--- a/src/common/kernel-consumer/kernel-consumer.c
+++ b/src/common/kernel-consumer/kernel-consumer.c
@@ -280,10 +280,21 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
 
 		goto end_nosignal;
 	}
-	case LTTNG_CONSUMER_DATA_AVAILABLE:
+	case LTTNG_CONSUMER_DATA_PENDING:
 	{
-		rcu_read_unlock();
-		return -ENOSYS;
+		int32_t ret;
+		uint64_t id = msg.u.data_pending.session_id;
+
+		DBG("Kernel consumer data pending command for id %" PRIu64, id);
+
+		ret = consumer_data_pending(id);
+
+		/* Send back returned value to session daemon */
+		ret = lttcomm_send_unix_sock(sock, &ret, sizeof(ret));
+		if (ret < 0) {
+			PERROR("send data pending ret code");
+		}
+		break;
 	}
 	default:
 		goto end_nosignal;
@@ -472,3 +483,32 @@ error:
 	return ret;
 }
 
+/*
+ * Check if data is still being extracted from the buffers for a specific
+ * stream. Consumer data lock MUST be acquired before calling this function
+ * and the stream lock.
+ *
+ * Return 1 if the traced data are still getting read else 0 meaning that the
+ * data is available for trace viewer reading.
+ */
+int lttng_kconsumer_data_pending(struct lttng_consumer_stream *stream)
+{
+	int ret;
+
+	assert(stream);
+
+	ret = kernctl_get_next_subbuf(stream->wait_fd);
+	if (ret == 0) {
+		/* There is still data so let's put back this subbuffer. */
+		ret = kernctl_put_subbuf(stream->wait_fd);
+		assert(ret == 0);
+		ret = 1;   /* Data is pending */
+		goto end;
+	}
+
+	/* Data is NOT pending and ready to be read. */
+	ret = 0;
+
+end:
+	return ret;
+}