[PATCH v7 14/59] perf python: Add wrapper for perf_data file abstraction

Ian Rogers
2026-04-25T22:51:02Z

The perf_data struct is needed for session supported.

Assisted-by: Gemini:gemini-3.1-pro-preview
Signed-off-by: Ian Rogers <irogers@google.com>
---
v2:
1. Fixed Memory & FD Leaks in pyrf_data__init : Added cleanup of old
state (closing file and freeing path) if __init__ is called
multiple times on the same object.

2. Fixed Invalid Free in pyrf_data__delete : Ensured pdata->data.path
is always dynamically allocated via strdup() , even for the default
"perf.data" . This avoids passing a static string literal to free().

3. Fixed NULL Pointer Dereference in pyrf_data__str : Added a check
for NULL path to prevent segfaults if str() or repr() is called on
an uninitialized object.

4. Guarded fd Argument Usage: Added a check to ensure that if an fd is
provided, it corresponds to a pipe, failing gracefully with a
ValueError otherwise.

v7:
- Added pyrf_data__new to zero-initialize pdata->data to fix
crash on re-initialization.
---
tools/perf/util/python.c | 103 ++++++++++++++++++++++++++++++++++++++-
1 file changed, 102 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/python.c b/tools/perf/util/python.c
index 2ba3556c4f16..aa63c7ffe822 100644
--- a/tools/perf/util/python.c
+++ b/tools/perf/util/python.c
@@ -10,6 +10,7 @@

#include "callchain.h"
#include "counts.h"
+#include "data.h"
#include "event.h"
#include "evlist.h"
#include "evsel.h"
@@ -2316,6 +2317,102 @@ static PyObject *pyrf__metrics(PyObject *self, PyObject *args)
return list;
}

+struct pyrf_data {
+ PyObject_HEAD
+
+ struct perf_data data;
+};
+
+static int pyrf_data__init(struct pyrf_data *pdata, PyObject *args, PyObject *kwargs)
+{
+ static char *kwlist[] = { "path", "fd", NULL };
+ char *path = NULL;
+ int fd = -1;
+
+ if (!PyArg_ParseTupleAndKeywords(args, kwargs, "|si", kwlist, &path, &fd))
+ return -1;
+
+ if (pdata->data.open)
+ perf_data__close(&pdata->data);
+ free((char *)pdata->data.path);
+
+ if (!path)
+ path = "perf.data";
+
+ pdata->data.path = strdup(path);
+ if (!pdata->data.path) {
+ PyErr_NoMemory();
+ return -1;
+ }
+
+ if (fd != -1) {
+ struct stat st;
+
+ if (fstat(fd, &st) < 0 || !S_ISFIFO(st.st_mode)) {
+ PyErr_SetString(PyExc_ValueError,
+ "fd argument is only supported for pipes");
+ free((char *)pdata->data.path);
+ pdata->data.path = NULL;
+ return -1;
+ }
+ }
+
+ pdata->data.mode = PERF_DATA_MODE_READ;
+ pdata->data.file.fd = fd;
+ if (perf_data__open(&pdata->data) < 0) {
+ PyErr_Format(PyExc_IOError, "Failed to open perf data: %s",
+ pdata->data.path ? pdata->data.path : "perf.data");
+ return -1;
+ }
+ return 0;
+}
+
+static void pyrf_data__delete(struct pyrf_data *pdata)
+{
+ perf_data__close(&pdata->data);
+ free((char *)pdata->data.path);
+ Py_TYPE(pdata)->tp_free((PyObject *)pdata);
+}
+
+static PyObject *pyrf_data__str(PyObject *self)
+{
+ const struct pyrf_data *pdata = (const struct pyrf_data *)self;
+
+ if (!pdata->data.path)
+ return PyUnicode_FromString("[uninitialized]");
+ return PyUnicode_FromString(pdata->data.path);
+}
+
+static PyObject *pyrf_data__new(PyTypeObject *type, PyObject *args, PyObject *kwargs)
+{
+ struct pyrf_data *pdata;
+
+ pdata = (struct pyrf_data *)PyType_GenericNew(type, args, kwargs);
+ if (pdata)
+ memset(&pdata->data, 0, sizeof(pdata->data));
+ return (PyObject *)pdata;
+}
+
+static const char pyrf_data__doc[] = PyDoc_STR("perf data file object.");
+
+static PyTypeObject pyrf_data__type = {
+ PyVarObject_HEAD_INIT(NULL, 0)
+ .tp_name = "perf.data",
+ .tp_basicsize = sizeof(struct pyrf_data),
+ .tp_dealloc = (destructor)pyrf_data__delete,
+ .tp_flags = Py_TPFLAGS_DEFAULT|Py_TPFLAGS_BASETYPE,
+ .tp_doc = pyrf_data__doc,
+ .tp_init = (initproc)pyrf_data__init,
+ .tp_repr = pyrf_data__str,
+ .tp_str = pyrf_data__str,
+};
+
+static int pyrf_data__setup_types(void)
+{
+ pyrf_data__type.tp_new = pyrf_data__new;
+ return PyType_Ready(&pyrf_data__type);
+}
+
static PyMethodDef perf__methods[] = {
{
.ml_name = "metrics",
@@ -2378,7 +2475,8 @@ PyMODINIT_FUNC PyInit_perf(void)
pyrf_cpu_map__setup_types() < 0 ||
pyrf_pmu_iterator__setup_types() < 0 ||
pyrf_pmu__setup_types() < 0 ||
- pyrf_counts_values__setup_types() < 0)
+ pyrf_counts_values__setup_types() < 0 ||
+ pyrf_data__setup_types() < 0)
return module;

/* The page_size is placed in util object. */
@@ -2426,6 +2524,9 @@ PyMODINIT_FUNC PyInit_perf(void)
Py_INCREF(&pyrf_counts_values__type);
PyModule_AddObject(module, "counts_values", (PyObject *)&pyrf_counts_values__type);

+ Py_INCREF(&pyrf_data__type);
+ PyModule_AddObject(module, "data", (PyObject *)&pyrf_data__type);
+
dict = PyModule_GetDict(module);
if (dict == NULL)
goto error;
--
2.54.0.545.g6539524ca2-goog