[PATCH 2/2 V2] tracecmd: Start of a tracecmd swig wrapper for python

[Darren Hart]

Introduce a python tracecmd module for use in rapidly prototyping
tracing applications. The interface description is provided in
tracecmd.i, it identifies which functions are available from within
python. A test python script is provided as tracecmd-test.py.

These bindings are expected to change significantly. Eventually I
would like to wrap this automated binding with more pythonic objects,
most likely including Trace and Event objects which merge the
functionality of tracecmd-input, pevent, record, and event structures.
This will make development of python apps much more accessible to many
application developers.

For now, this is mostly a proof of concept and is no where near
complete. It can however open a trace file and read all the events from
it, displaying them by CPU in chronological order.

V2: simplified interface file with some SWIG ifdefs in the header files

Signed-off-by: Darren Hart <dvhltc@xxxxxxxxxx>
---
 parse-events.h   |    9 +++++++++
 swig.sh          |   19 +++++++++++++++++++
 trace-cmd.h      |    2 ++
 tracecmd-test.py |   38 ++++++++++++++++++++++++++++++++++++++
 tracecmd.i       |   12 ++++++++++++
 5 files changed, 80 insertions(+), 0 deletions(-)
 create mode 100755 swig.sh
 create mode 100755 tracecmd-test.py
 create mode 100644 tracecmd.i

diff --git a/parse-events.h b/parse-events.h
index e6f5806..0d68f23 100644
--- a/parse-events.h
+++ b/parse-events.h
@@ -42,6 +42,8 @@ trace_seq_init(struct trace_seq *s)
 	s->full = 0;
 }
 
+/* SWIG doesn't like the __attribute__, don't export trace_seq to python */
+#ifndef SWIG
 extern int trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
 	__attribute__ ((format (printf, 2, 3)));
 extern int trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args)
@@ -53,6 +55,7 @@ extern int trace_seq_putc(struct trace_seq *s, unsigned char c);
 extern void trace_seq_terminate(struct trace_seq *s);
 
 extern int trace_seq_do_printf(struct trace_seq *s);
+#endif
 
 
 /* ----------------------- pevent ----------------------- */
@@ -275,7 +278,10 @@ struct pevent {
 	struct format_field *bprint_buf_field;
 };
 
+/* this doesn't appear to be defined anywhere... */
+#ifndef SWIG
 void parse_set_info(struct pevent *pevent, int nr_cpus, int long_sz);
+#endif
 
 void die(char *fmt, ...);
 void *malloc_or_die(unsigned int size);
@@ -374,8 +380,11 @@ struct event *pevent_find_event(struct pevent *pevent, int id);
 struct event *
 pevent_find_event_by_name(struct pevent *pevent, const char *sys, const char *name);
 
+/* SWIG doesn't like __unused */
+#ifndef SWIG
 void pevent_data_lat_fmt(struct pevent *pevent,
 			 struct trace_seq *s, void *data, int size __unused);
+#endif
 int pevent_data_type(struct pevent *pevent, struct record *rec);
 struct event *pevent_data_event_from_type(struct pevent *pevent, int type);
 int pevent_data_pid(struct pevent *pevent, struct record *rec);
diff --git a/swig.sh b/swig.sh
new file mode 100755
index 0000000..9a77ec2
--- /dev/null
+++ b/swig.sh
@@ -0,0 +1,19 @@
+#!/bin/sh
+
+# Temporary hack of a build script, eventually we'll incoroporate this
+# into the Makefile. You may have to update the includes to point to your
+# python installation.
+
+rm tracecmd_wrap.c tracecmd_wrap.o _tracecmd.so &> /dev/null
+
+swig -Wall -python tracecmd.i
+
+gcc -fpic -c  -I/usr/include/python2.6/ -I/usr/lib/python2.6/config \
+    parse_events.c trace-read.c trace-output.c trace-cmd.c \
+    trace-record.c trace-input.c tracecmd_wrap.c
+
+gcc -shared trace-ftrace.o trace-seq.o trace-util.o \
+    parse-events.o trace-read.o trace-output.o trace-cmd.o \
+    trace-record.o trace-input.o tracecmd_wrap.o \
+    -o _tracecmd.so
+
diff --git a/trace-cmd.h b/trace-cmd.h
index 1c4d359..6f645c5 100644
--- a/trace-cmd.h
+++ b/trace-cmd.h
@@ -83,8 +83,10 @@ int tracecmd_set_cpu_to_timestamp(struct tracecmd_input *handle,
 int tracecmd_ftrace_overrides(struct tracecmd_input *handle);
 struct pevent *tracecmd_get_pevent(struct tracecmd_input *handle);
 
+#ifndef SWIG
 /* hack for function graph work around */
 extern __thread struct tracecmd_input *tracecmd_curr_thread_handle;
+#endif
 
 
 /* --- Creating and Writing the trace.dat file --- */
diff --git a/tracecmd-test.py b/tracecmd-test.py
new file mode 100755
index 0000000..dd0a583
--- /dev/null
+++ b/tracecmd-test.py
@@ -0,0 +1,38 @@
+#!/usr/bin/env python
+
+from tracecmd import *
+# import the struct_member_get() wrappers
+from _tracecmd import *
+
+# Let's move the following into a new Trace object constructor
+filename = "trace.dat"
+trace_file = open(filename)
+handle = tracecmd_open(trace_file.fileno())
+tracecmd_read_headers(handle)
+tracecmd_init_data(handle)
+
+# These should be members, i.e. Trace.cpus
+pe = tracecmd_get_pevent(handle)
+cpus = tracecmd_cpus(handle)
+print "Trace %s contains data for %d cpus" % (filename, cpus) 
+
+# FIXME: this doesn't print anything...
+tracecmd_print_events(handle)
+
+print "Cycling through the events for each CPU"
+for cpu in range(0,cpus):
+    print "CPU", cpu
+    rec = tracecmd_read_data(handle, cpu)
+    while True:
+        if rec:
+            # these should be members of a Record object
+            pid = pevent_data_pid(pe, rec)
+            comm = pevent_data_comm_from_pid(pe, pid)
+            type = pevent_data_type(pe, rec)
+            event = pevent_data_event_from_type(pe, type)
+            print "\t%f %s: pid=%d comm=%s type=%d" % \
+                  (record_ts_get(rec), event_name_get(event), pid, comm, type)
+
+            rec = tracecmd_read_data(handle, cpu)
+        else:
+            break
diff --git a/tracecmd.i b/tracecmd.i
new file mode 100644
index 0000000..0245552
--- /dev/null
+++ b/tracecmd.i
@@ -0,0 +1,12 @@
+// tracecmd.i
+%module tracecmd
+
+%{
+#include "trace-cmd.h"
+%}
+
+%inline %{
+%}
+
+%include "trace-cmd.h"
+%include "parse-events.h"
-- 
1.6.3.3

--
Darren Hart
IBM Linux Technology Center
Real-Time Linux Team
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