From: "Steven Rostedt (Google)" <rostedt@xxxxxxxxxxx>
The tracecmd_set_private() and tracecmd_get_private() functions were not
in the man pages. Add them, and also add a working example for the
tracecmd_open() (and other) function.
Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
---
.../libtracecmd/libtracecmd-files.txt | 72 ++++++++++++-------
Documentation/libtracecmd/libtracecmd.txt | 2 +
2 files changed, 50 insertions(+), 24 deletions(-)
diff --git a/Documentation/libtracecmd/libtracecmd-files.txt b/Documentation/libtracecmd/libtracecmd-files.txt
index 382603efd50d..f8292cb4cbd5 100644
--- a/Documentation/libtracecmd/libtracecmd-files.txt
+++ b/Documentation/libtracecmd/libtracecmd-files.txt
@@ -4,7 +4,7 @@ libtracecmd(3)
NAME
----
tracecmd_open, tracecmd_open_fd, tracecmd_open_head, tracecmd_init_data,
-tracecmd_close - Open and close a trace file.
+tracecmd_close, tracecmd_set_private, tracecmd_get_private - Open and close a trace file.
SYNOPSIS
--------
@@ -17,6 +17,8 @@ struct tracecmd_input pass:[*]*tracecmd_open_fd*(int _fd_, int _flags_);
struct tracecmd_input pass:[*]*tracecmd_open_head*(const char pass:[*]_file_, int _flags_);
int *tracecmd_init_data*(struct tracecmd_input pass:[*]_handle_);
void *tracecmd_close*(struct tracecmd_input pass:[*]_handle_);
+void *tracecmd_set_private*(struct tracecmd_input pass:[*]_handle_, void pass:[*]_data_);
+void pass:[*]*tracecmd_get_private*(struct tracecmd_input pass:[*]_handle_);
--
DESCRIPTION
@@ -55,6 +57,12 @@ The *tracecmd_close()* function frees a _handle_, pointer to tracecmd_input
structure, previously allocated with *tracecmd_open()*, *tracecmd_open_fd()*
or *tracecmd_open_head()* APIs.
+The *tracecmd_set_private()* function allows to add specific _data_ to the
+_handle_ that can be retrieved later.
+
+The *tracecmd_get_private()* function will retrieve the _data_ set by
+*tracecmd_set_private()* for the given _handle_.
+
RETURN VALUE
------------
The *tracecmd_open()*, *tracecmd_open_fd()* and *tracecmd_open_head()*
@@ -66,6 +74,8 @@ when *tracecmd_close()* is called to close it, that fd will be closed also.
The *tracecmd_init_data()* function returns -1 in case of an error or
0 otherwise.
+The *tracecmd_get_private()* returns the _data_ set by *tracecmd_set_private()*.
+
EXAMPLE
-------
[source,c]
@@ -75,32 +85,46 @@ a trace file, which can be used depending on the use case.
1. Open and initialise the trace file in а single step:
+#include <stdlib.h>
#include <trace-cmd.h>
-...
-struct tracecmd_input *handle = tracecmd_open("trace.dat");
- if (!handle) {
- /* Failed to open trace.dat file */
- }
-...
- /* Read tracing data from the file, using the handle */
-...
- tracecmd_close(handle);
-...
-int fd;
- fd = = open("trace.dat", O_RDONLY);
- if (fd < 0) {
- /* Failed to open trace file for reading */
- }
- handle = tracecmd_open_fd(fd);
- if (!handle) {
- close(fd);
- /* Failed to initialise handler for reading the trace file */
+
+static int print_events(struct tracecmd_input *handle, struct tep_record *record, int cpu, void *data)
+{
+ static struct trace_seq seq;
+ struct tep_handle *tep = tracecmd_get_tep(handle);
+ const char *file = tracecmd_get_private(handle);
+
+ if (!seq.buffer)
+ trace_seq_init(&seq);
+
+ trace_seq_reset(&seq);
+ trace_seq_printf(&seq, "%s: ", file);
+ tep_print_event(tep, &seq, record, "%6.1000d [%03d] %s-%d %s: %s\n",
+ TEP_PRINT_TIME, TEP_PRINT_CPU, TEP_PRINT_COMM, TEP_PRINT_PID,
+ TEP_PRINT_NAME, TEP_PRINT_INFO);
+ trace_seq_terminate(&seq);
+ trace_seq_do_printf(&seq);
+ return 0;
+}
+
+int main(int argc, char **argv)
+{
+ struct tracecmd_input *handle;
+
+ if (argc < 2) {
+ printf("usage: %s trace.dat\n", argv[0]);
+ exit(-1);
}
-...
- /* Read tracing data from the file, using the handle */
-...
+
+ handle = tracecmd_open(argv[i], 0);
+ if (!handle)
+ exit(-1);
+
+ tracecmd_set_private(handles[nr_handles], argv[i]);
+ tracecmd_iterate_events(handles, NULL, 0, print_events, NULL);
+
tracecmd_close(handle);
-...
+}
2. Open and initialise the trace file in two steps. This allows to perform
some processing based on metadata, read from the file, before initialising
diff --git a/Documentation/libtracecmd/libtracecmd.txt b/Documentation/libtracecmd/libtracecmd.txt
index 1939c209dc34..141fec5d379c 100644
--- a/Documentation/libtracecmd/libtracecmd.txt
+++ b/Documentation/libtracecmd/libtracecmd.txt
@@ -16,6 +16,8 @@ Open and close trace file:
struct tracecmd_input pass:[*]*tracecmd_open_fd*(int _fd_, int _flags_);
struct tracecmd_input pass:[*]*tracecmd_open_head*(const char pass:[*]_file_, int _flags_);
void *tracecmd_close*(struct tracecmd_input pass:[*]_handle_);
+ void *tracecmd_set_private*(struct tracecmd_input pass:[*]_handle_, void pass:[*]_data_);
+ void pass:[*]*tracecmd_get_private*(struct tracecmd_input pass:[*]_handle_);
Read tracing records from a trace file:
int *tracecmd_init_data*(struct tracecmd_input pass:[*]_handle_);
--
2.35.1
|