The user_stack and kernel_stack events are special in that they are dynamic
arrays but aren't labeled as __data_loc like other dynamic arrays. This isn't a
big deal since they look the same, they have a "caller" field which is an array
of unsigned longs. This patch adds a helper to the python bindings to read
these arrays in, lookup the function and append them to a python list.
Signed-off-by: Josef Bacik <jba...@fb.com>
---
NOTE: This patch replaces the one I sent yesterday
trace-cmd: add helper to read kernel_stack functions
This is cleaner and gives us a nice list of the functions and works for both
kernel_stack and user_stack events.
ctracecmd.i | 37 +++++++++++++++++++++++++++++++++++++
tracecmd.py | 8 ++++++++
2 files changed, 45 insertions(+)
diff --git a/ctracecmd.i b/ctracecmd.i
index 3970803..3b80f01 100644
--- a/ctracecmd.i
+++ b/ctracecmd.i
@@ -49,6 +49,43 @@ void py_pevent_register_event_handler(struct pevent *pevent,
int id,
python_callback, pyfunc);
}
+static PyObject *py_field_get_stack(struct pevent *pevent,
+ struct pevent_record *record,
+ struct event_format *event,
+ int long_size)
+{
+ PyObject *list;
+ struct format_field *field;
+ void *data = record->data;
+ const char *func = NULL;
+ unsigned long addr;
+
+ field = pevent_find_any_field(event, "caller");
+ if (!field) {
+ PyErr_SetString(PyExc_TypeError,
+ "Event doesn't have caller field");
+ return NULL;
+ }
+
+ list = PyList_New(0);
+
+ for (data += field->offset; data < record->data + record->size;
+ data += long_size) {
+ addr = pevent_read_number(event->pevent, data, long_size);
+
+ if ((long_size == 8 && addr == (unsigned long long)-1) ||
+ ((int)addr == -1))
+ break;
+ func = pevent_find_function(event->pevent, addr);
+ if (PyList_Append(list, PyString_FromString(func))) {
+ Py_DECREF(list);
+ return NULL;
+ }
+ }
+
+ return list;
+}
+
static PyObject *py_field_get_data(struct format_field *f, struct
pevent_record *r)
{
if (!strncmp(f->type, "__data_loc ", 11)) {
diff --git a/tracecmd.py b/tracecmd.py
index cdd619b..358185b 100644
--- a/tracecmd.py
+++ b/tracecmd.py
@@ -117,6 +117,10 @@ class Event(object, DictMixin):
return None
return py_field_get_str(f, self._record)
+ def stack_field(self, long_size):
+ return py_field_get_stack(self._pevent, self._record, self._format,
+ long_size)
+
class TraceSeq(object):
def __init__(self, trace_seq):
self._trace_seq = trace_seq
@@ -192,6 +196,10 @@ class Trace(object):
def cpus(self):
return tracecmd_cpus(self._handle)
+ @cached_property
+ def long_size(self):
+ return tracecmd_long_size(self._handle)
+
def read_event(self, cpu):
rec = tracecmd_read_data(self._handle, cpu)
if rec:
--
1.9.3
--
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