[PATCH v2 02/10] trace-cmd library: New API for setting a message context to an output handler

["Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com>]

The new API associates previously created handler to message context
with given output handler. The message context is used by the output
handler to send data over a network, instead writing to a local file.
 tracecmd_output_allocate()

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 .../include/private/trace-cmd-private.h       |  2 ++
 lib/trace-cmd/trace-output.c                  | 22 +++++++++++++++++++
 2 files changed, 24 insertions(+)

diff --git a/lib/trace-cmd/include/private/trace-cmd-private.h b/lib/trace-cmd/include/private/trace-cmd-private.h
index bed96657..49c8c138 100644
--- a/lib/trace-cmd/include/private/trace-cmd-private.h
+++ b/lib/trace-cmd/include/private/trace-cmd-private.h
@@ -270,6 +270,8 @@ struct tracecmd_option;
 struct tracecmd_msg_handle;
 
 struct tracecmd_output *tracecmd_output_allocate(int fd);
+int tracecmd_output_set_msg(struct tracecmd_output *handler,
+			    struct tracecmd_msg_handle *msg_handle);
 struct tracecmd_output *tracecmd_create_file_latency(const char *output_file, int cpus);
 struct tracecmd_output *
 tracecmd_create_init_file_glob(const char *output_file,
diff --git a/lib/trace-cmd/trace-output.c b/lib/trace-cmd/trace-output.c
index 3878b963..d73c4f99 100644
--- a/lib/trace-cmd/trace-output.c
+++ b/lib/trace-cmd/trace-output.c
@@ -918,6 +918,28 @@ struct tracecmd_output *tracecmd_output_allocate(int fd)
 	return handle;
 }
 
+/**
+ * tracecmd_output_set_msg - associated an output file handler with network message handler
+ * @handle: output handler to a trace file.
+ * @msg_handle: network handler, allocated by tracecmd_msg_handle_alloc()
+ *
+ * This API associates an output file handler with a network stream. All subsequent API calls
+ * with this output file handler will send data over the network using the @msg_handle, instead
+ * of writing to a file.
+ * This API must be called after the handler file version is set and before
+ * tracecmd_output_write_init().
+ *
+ * Returns 0 on success, or -1 if the output file handler is not allocated or not in expected state.
+ */
+int tracecmd_output_set_msg(struct tracecmd_output *handler, struct tracecmd_msg_handle *msg_handle)
+{
+	if (!handler || handler->file_state != TRACECMD_FILE_ALLOCATED)
+		return -1;
+
+	handler->msg_handle = msg_handle;
+
+	return 0;
+}
 
 static int select_file_version(struct tracecmd_output *handle,
 				struct tracecmd_input *ihandle)
-- 
2.33.1