[PATCH v4 03/25] trace-cmd library: New APIs to get and set version of output handler

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

There are cases where the version of the file, associated with given
output handler must be get or set. Added new APIs for such use cases:
  tracecmd_get_out_file_version()
  tracecmd_output_set_version()

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 .../include/private/trace-cmd-private.h       |  2 ++
 lib/trace-cmd/trace-output.c                  | 29 +++++++++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/lib/trace-cmd/include/private/trace-cmd-private.h b/lib/trace-cmd/include/private/trace-cmd-private.h
index 460f8a5d..ae930c2f 100644
--- a/lib/trace-cmd/include/private/trace-cmd-private.h
+++ b/lib/trace-cmd/include/private/trace-cmd-private.h
@@ -281,6 +281,7 @@ int tracecmd_output_set_msg(struct tracecmd_output *handler,
 int tracecmd_output_set_trace_dir(struct tracecmd_output *handler, const char *tracing_dir);
 int tracecmd_output_set_kallsyms(struct tracecmd_output *handler, const char *kallsyms);
 int tracecmd_output_set_from_input(struct tracecmd_output *handler, struct tracecmd_input *ihandle);
+int tracecmd_output_set_version(struct tracecmd_output *handler, int file_version);
 int tracecmd_output_write_init(struct tracecmd_output *handler);
 int tracecmd_output_write_headers(struct tracecmd_output *handler,
 				  struct tracecmd_event_list *list);
@@ -315,6 +316,7 @@ int tracecmd_append_cpu_data(struct tracecmd_output *handle,
 int tracecmd_append_buffer_cpu_data(struct tracecmd_output *handle,
 				    const char *name, int cpus, char * const *cpu_data_files);
 struct tracecmd_output *tracecmd_get_output_handle_fd(int fd);
+unsigned long tracecmd_get_out_file_version(struct tracecmd_output *handle);
 
 /* --- Reading the Fly Recorder Trace --- */
 
diff --git a/lib/trace-cmd/trace-output.c b/lib/trace-cmd/trace-output.c
index 10e5875f..fa11fe77 100644
--- a/lib/trace-cmd/trace-output.c
+++ b/lib/trace-cmd/trace-output.c
@@ -1055,6 +1055,26 @@ int tracecmd_output_set_from_input(struct tracecmd_output *handler, struct trace
 	return 0;
 }
 
+/**
+ * tracecmd_output_set_version - Set file version of the output handler
+ * @handle: output handler to a trace file.
+ * @file_version: desired file version
+ *
+ * This API must be called 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_version(struct tracecmd_output *handler, int file_version)
+{
+	if (!handler || handler->file_state != TRACECMD_FILE_ALLOCATED)
+		return -1;
+	if (file_version < FILE_VERSION_MIN || file_version > FILE_VERSION_MAX)
+		return -1;
+	handler->file_version = file_version;
+	return 0;
+}
+
+
 /**
  * tracecmd_output_write_init - Write the initial magics in the trace file
  * @handle: output handler to a trace file.
@@ -1882,3 +1902,12 @@ __hidden bool check_out_state(struct tracecmd_output *handle, int new_state)
 {
 	return check_file_state(handle->file_version, handle->file_state, new_state);
 }
+
+/**
+ * tracecmd_get_out_file_version - return the trace.dat file version
+ * @handle: output handle for the trace.dat file
+ */
+unsigned long tracecmd_get_out_file_version(struct tracecmd_output *handle)
+{
+	return handle->file_version;
+}
-- 
2.31.1