The API only allocates a handler and performs minimal initialization.
No data is written in the file.
tracecmd_output_allocate()
Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@xxxxxxxxx>
---
.../include/private/trace-cmd-private.h | 4 ++-
lib/trace-cmd/trace-output.c | 36 +++++++++++++++++++
2 files changed, 39 insertions(+), 1 deletion(-)
diff --git a/lib/trace-cmd/include/private/trace-cmd-private.h b/lib/trace-cmd/include/private/trace-cmd-private.h
index c58b09e9..b4cee0f6 100644
--- a/lib/trace-cmd/include/private/trace-cmd-private.h
+++ b/lib/trace-cmd/include/private/trace-cmd-private.h
@@ -102,7 +102,8 @@ static inline int tracecmd_host_bigendian(void)
/* --- Opening and Reading the trace.dat file --- */
enum tracecmd_file_states {
- TRACECMD_FILE_INIT = 1,
+ TRACECMD_FILE_ALLOCATED = 0,
+ TRACECMD_FILE_INIT,
TRACECMD_FILE_HEADERS,
TRACECMD_FILE_FTRACE_EVENTS,
TRACECMD_FILE_ALL_EVENTS,
@@ -268,6 +269,7 @@ struct tracecmd_event_list {
struct tracecmd_option;
struct tracecmd_msg_handle;
+struct tracecmd_output *tracecmd_output_allocate(int fd);
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 fe1d1aaa..3878b963 100644
--- a/lib/trace-cmd/trace-output.c
+++ b/lib/trace-cmd/trace-output.c
@@ -59,6 +59,7 @@ struct tracecmd_output {
unsigned long file_state;
unsigned long file_version;
size_t options_start;
+ bool big_endian;
struct list_head options;
struct tracecmd_msg_handle *msg_handle;
@@ -883,6 +884,41 @@ out_free:
return ret;
}
+/**
+ * tracecmd_output_allocate - allocate new output handler to a trace file
+ * @handle: file descriptor to an empty file, it can be -1 if the handler
+ * will not write to a file
+ *
+ * This API only allocates a handler and performs minimal initialization.
+ * No data is written in the file.
+ *
+ * Returns pointer to a newly allocated file descriptor, that can be used
+ * with other library APIs. In case of an error, NULL is returned. The returned
+ * handler must be freed with tracecmd_output_close() or tracecmd_output_free()
+ */
+struct tracecmd_output *tracecmd_output_allocate(int fd)
+{
+ struct tracecmd_output *handle;
+
+ handle = calloc(1, sizeof(*handle));
+ if (!handle)
+ return NULL;
+
+ handle->fd = fd;
+
+ handle->file_version = FILE_VERSION;
+
+ handle->page_size = getpagesize();
+ handle->big_endian = tracecmd_host_bigendian();
+
+ list_head_init(&handle->options);
+
+ handle->file_state = TRACECMD_FILE_ALLOCATED;
+
+ return handle;
+}
+
+
static int select_file_version(struct tracecmd_output *handle,
struct tracecmd_input *ihandle)
{
--
2.31.1
|