Add an API to create a tracecmd_handle from a file,
read and parse only the trace headers from the file.
This allows to implement opening a trace file on
stages - reading the trace headers and reading the trace data.
Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@xxxxxxxxx>
---
include/trace-cmd/trace-cmd.h | 1 +
lib/trace-cmd/trace-input.c | 28 ++++++++++++++++++++++++++++
2 files changed, 29 insertions(+)
diff --git a/include/trace-cmd/trace-cmd.h b/include/trace-cmd/trace-cmd.h
index 3f96bbde..e22aa251 100644
--- a/include/trace-cmd/trace-cmd.h
+++ b/include/trace-cmd/trace-cmd.h
@@ -143,6 +143,7 @@ typedef void (*tracecmd_handle_init_func)(struct tracecmd_input *handle,
struct tracecmd_input *tracecmd_alloc(const char *file);
struct tracecmd_input *tracecmd_alloc_fd(int fd);
struct tracecmd_input *tracecmd_open(const char *file);
+struct tracecmd_input *tracecmd_open_head(const char *file);
struct tracecmd_input *tracecmd_open_fd(int fd);
void tracecmd_ref(struct tracecmd_input *handle);
void tracecmd_close(struct tracecmd_input *handle);
diff --git a/lib/trace-cmd/trace-input.c b/lib/trace-cmd/trace-input.c
index ee9bfb52..efc8d4bd 100644
--- a/lib/trace-cmd/trace-input.c
+++ b/lib/trace-cmd/trace-input.c
@@ -3175,6 +3175,34 @@ struct tracecmd_input *tracecmd_open(const char *file)
return tracecmd_open_fd(fd);
}
+/**
+ * tracecmd_open_head - create a tracecmd_handle from a given file, read
+ * read and parse only the trace headers from the file
+ * @file: the file name of the file that is of tracecmd data type.
+ */
+struct tracecmd_input *tracecmd_open_head(const char *file)
+{
+ struct tracecmd_input *handle;
+ int fd;
+
+ fd = open(file, O_RDONLY);
+ if (fd < 0)
+ return NULL;
+
+ handle = tracecmd_alloc_fd(fd);
+ if (!handle)
+ return NULL;
+
+ if (tracecmd_read_headers(handle) < 0)
+ goto fail;
+
+ return handle;
+
+fail:
+ tracecmd_close(handle);
+ return NULL;
+}
+
/**
* tracecmd_ref - add a reference to the handle
* @handle: input handle for the trace.dat file
--
2.25.1
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