[PATCH v9 20/23] perf python: Add syscall name/id to convert syscall number and name

[Ian Rogers]

Use perf's syscalltbl support to convert syscall number to name
assuming the number is for the host machine. This avoids python
libaudit support as tools/perf/scripts/python/syscall-counts.py
requires.

Assisted-by: Gemini:gemini-3.1-pro-preview
Signed-off-by: Ian Rogers <irogers at google.com>
---
v2:

1. Guarded with HAVE_LIBTRACEEVENT : Wrapped the syscall functions and
   their entries in perf__methods with #ifdef HAVE_LIBTRACEEVENT to
   avoid potential linker errors if CONFIG_TRACE is disabled.

2. Changed Exception Type: Updated pyrf__syscall_id to raise a
   ValueError instead of a TypeError when a syscall is not found.

3. Fixed Typo: Corrected "name number" to "name" in the docstring for
   syscall_id.

v6:
- Added optional keyword-only `elf_machine` argument to `syscall_name`
  and `syscall_id`.

v7:
- Made syscalltbl.o unconditional in Build to fix undefined symbol
  when building without libtraceevent.
---
 tools/perf/util/Build    |  1 -
 tools/perf/util/python.c | 48 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 48 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/Build b/tools/perf/util/Build
index 4bbc78b1f741..e37779f9dfe4 100644
--- a/tools/perf/util/Build
+++ b/tools/perf/util/Build
@@ -75,7 +75,6 @@ perf-util-y += sample.o
 perf-util-y += sample-raw.o
 perf-util-y += s390-sample-raw.o
 perf-util-y += amd-sample-raw.o
-
 perf-util-y += ordered-events.o
 perf-util-y += namespaces.o
 perf-util-y += comm.o
diff --git a/tools/perf/util/python.c b/tools/perf/util/python.c
index 218d772346e2..23eb65adb392 100644
--- a/tools/perf/util/python.c
+++ b/tools/perf/util/python.c
@@ -18,6 +18,7 @@
 #include "data.h"
 #include "debug.h"
 #include "dso.h"
+#include "dwarf-regs.h"
 #include "event.h"
 #include "branch.h"
 #include "evlist.h"
@@ -35,6 +36,7 @@
 #include "srcline.h"
 #include "strbuf.h"
 #include "symbol.h"
+#include "trace/beauty/syscalltbl.h"
 #include "thread.h"
 #include "thread_map.h"
 #include "tool.h"
@@ -3792,6 +3794,40 @@ static int pyrf_session__setup_types(void)
 	return PyType_Ready(&pyrf_session__type);
 }
 
+static PyObject *pyrf__syscall_name(PyObject *self, PyObject *args, PyObject *kwargs)
+{
+	const char *name;
+	int id;
+	int elf_machine = EM_HOST;
+	static char * const kwlist[] = { "id", "elf_machine", NULL };
+
+	if (!PyArg_ParseTupleAndKeywords(args, kwargs, "i|$i", kwlist, &id, &elf_machine))
+		return NULL;
+
+	name = syscalltbl__name(elf_machine, id);
+	if (!name)
+		Py_RETURN_NONE;
+	return PyUnicode_FromString(name);
+}
+
+static PyObject *pyrf__syscall_id(PyObject *self, PyObject *args, PyObject *kwargs)
+{
+	const char *name;
+	int id;
+	int elf_machine = EM_HOST;
+	static char * const kwlist[] = { "name", "elf_machine", NULL };
+
+	if (!PyArg_ParseTupleAndKeywords(args, kwargs, "s|$i", kwlist, &name, &elf_machine))
+		return NULL;
+
+	id = syscalltbl__id(elf_machine, name);
+	if (id < 0) {
+		PyErr_Format(PyExc_ValueError, "Failed to find syscall %s", name);
+		return NULL;
+	}
+	return PyLong_FromLong(id);
+}
+
 static PyMethodDef perf__methods[] = {
 	{
 		.ml_name  = "metrics",
@@ -3825,6 +3861,18 @@ static PyMethodDef perf__methods[] = {
 		.ml_flags = METH_NOARGS,
 		.ml_doc	  = PyDoc_STR("Returns a sequence of pmus.")
 	},
+	{
+		.ml_name  = "syscall_name",
+		.ml_meth  = (PyCFunction) pyrf__syscall_name,
+		.ml_flags = METH_VARARGS | METH_KEYWORDS,
+		.ml_doc	  = PyDoc_STR("Turns a syscall number to a string.")
+	},
+	{
+		.ml_name  = "syscall_id",
+		.ml_meth  = (PyCFunction) pyrf__syscall_id,
+		.ml_flags = METH_VARARGS | METH_KEYWORDS,
+		.ml_doc	  = PyDoc_STR("Turns a syscall name to a number.")
+	},
 	{ .ml_name = NULL, }
 };
 
-- 
2.54.0.794.g4f17f83d09-goog