gh-115773: Add tests to exercise the _Py_DebugOffsets structure (#115774)

Author: pablogsal

Diff for: Include/internal/pycore_runtime.h

@@ -55,74 +55,81 @@ typedef struct _Py_DebugOffsets {
     uint64_t version;
     // Runtime state offset;
     struct _runtime_state {
-        off_t finalizing;
-        off_t interpreters_head;
+        uint64_t finalizing;
+        uint64_t interpreters_head;
     } runtime_state;
 
     // Interpreter state offset;
     struct _interpreter_state {
-        off_t next;
-        off_t threads_head;
-        off_t gc;
-        off_t imports_modules;
-        off_t sysdict;
-        off_t builtins;
-        off_t ceval_gil;
-        off_t gil_runtime_state_locked;
-        off_t gil_runtime_state_holder;
+        uint64_t next;
+        uint64_t threads_head;
+        uint64_t gc;
+        uint64_t imports_modules;
+        uint64_t sysdict;
+        uint64_t builtins;
+        uint64_t ceval_gil;
+        uint64_t gil_runtime_state_locked;
+        uint64_t gil_runtime_state_holder;
     } interpreter_state;
 
     // Thread state offset;
     struct _thread_state{
-        off_t prev;
-        off_t next;
-        off_t interp;
-        off_t current_frame;
-        off_t thread_id;
-        off_t native_thread_id;
+        uint64_t prev;
+        uint64_t next;
+        uint64_t interp;
+        uint64_t current_frame;
+        uint64_t thread_id;
+        uint64_t native_thread_id;
     } thread_state;
 
     // InterpreterFrame offset;
     struct _interpreter_frame {
-        off_t previous;
-        off_t executable;
-        off_t instr_ptr;
-        off_t localsplus;
-        off_t owner;
+        uint64_t previous;
+        uint64_t executable;
+        uint64_t instr_ptr;
+        uint64_t localsplus;
+        uint64_t owner;
     } interpreter_frame;
 
     // CFrame offset;
     struct _cframe {
-        off_t current_frame;
-        off_t previous;
+        uint64_t current_frame;
+        uint64_t previous;
     } cframe;
 
     // Code object offset;
     struct _code_object {
-        off_t filename;
-        off_t name;
-        off_t linetable;
-        off_t firstlineno;
-        off_t argcount;
-        off_t localsplusnames;
-        off_t localspluskinds;
-        off_t co_code_adaptive;
+        uint64_t filename;
+        uint64_t name;
+        uint64_t linetable;
+        uint64_t firstlineno;
+        uint64_t argcount;
+        uint64_t localsplusnames;
+        uint64_t localspluskinds;
+        uint64_t co_code_adaptive;
     } code_object;
 
     // PyObject offset;
     struct _pyobject {
-        off_t ob_type;
+        uint64_t ob_type;
     } pyobject;
 
     // PyTypeObject object offset;
     struct _type_object {
-        off_t tp_name;
+        uint64_t tp_name;
     } type_object;
 
     // PyTuple object offset;
     struct _tuple_object {
-        off_t ob_item;
+        uint64_t ob_item;
     } tuple_object;
+
+    // Unicode object offset;
+    struct _unicode_object {
+        uint64_t state;
+        uint64_t length;
+        size_t asciiobject_size;
+    } unicode_object;
 } _Py_DebugOffsets;
 
 /* Full Python runtime state */

Diff for: Include/internal/pycore_runtime_init.h

@@ -83,6 +83,11 @@ extern PyTypeObject _PyExc_MemoryError;
             .tuple_object = { \
                 .ob_item = offsetof(PyTupleObject, ob_item), \
             }, \
+            .unicode_object = { \
+                .state = offsetof(PyUnicodeObject, _base._base.state), \
+                .length = offsetof(PyUnicodeObject, _base._base.length), \
+                .asciiobject_size = sizeof(PyASCIIObject), \
+            }, \
         }, \
         .allocators = { \
             .standard = _pymem_allocators_standard_INIT(runtime), \

Diff for: Lib/test/test_external_inspection.py

@@ -0,0 +1,84 @@
+import unittest
+import os
+import textwrap
+import importlib
+import sys
+from test.support import os_helper, SHORT_TIMEOUT
+from test.support.script_helper import make_script
+
+import subprocess
+
+PROCESS_VM_READV_SUPPORTED = False
+
+try:
+    from _testexternalinspection import PROCESS_VM_READV_SUPPORTED
+    from _testexternalinspection import get_stack_trace
+except ImportError:
+    unittest.skip("Test only runs when _testexternalinspection is available")
+
+def _make_test_script(script_dir, script_basename, source):
+    to_return = make_script(script_dir, script_basename, source)
+    importlib.invalidate_caches()
+    return to_return
+
+class TestGetStackTrace(unittest.TestCase):
+
+    @unittest.skipIf(sys.platform != "darwin" and sys.platform != "linux", "Test only runs on Linux and MacOS")
+    @unittest.skipIf(sys.platform == "linux" and not PROCESS_VM_READV_SUPPORTED, "Test only runs on Linux with process_vm_readv support")
+    def test_remote_stack_trace(self):
+        # Spawn a process with some realistic Python code
+        script = textwrap.dedent("""\
+            import time, sys, os
+            def bar():
+                for x in range(100):
+                    if x == 50:
+                        baz()
+            def baz():
+                foo()
+
+            def foo():
+                fifo = sys.argv[1]
+                with open(sys.argv[1], "w") as fifo:
+                    fifo.write("ready")
+                time.sleep(1000)
+
+            bar()
+            """)
+        stack_trace = None
+        with os_helper.temp_dir() as work_dir:
+            script_dir = os.path.join(work_dir, "script_pkg")
+            os.mkdir(script_dir)
+            fifo = f"{work_dir}/the_fifo"
+            os.mkfifo(fifo)
+            script_name = _make_test_script(script_dir, 'script', script)
+            try:
+                p = subprocess.Popen([sys.executable, script_name,  str(fifo)])
+                with open(fifo, "r") as fifo_file:
+                    response = fifo_file.read()
+                self.assertEqual(response, "ready")
+                stack_trace = get_stack_trace(p.pid)
+            except PermissionError:
+                self.skipTest("Insufficient permissions to read the stack trace")
+            finally:
+                os.remove(fifo)
+                p.kill()
+                p.terminate()
+                p.wait(timeout=SHORT_TIMEOUT)
+
+
+            expected_stack_trace = [
+                'foo',
+                'baz',
+                'bar',
+                '<module>'
+            ]
+            self.assertEqual(stack_trace, expected_stack_trace)
+
+    @unittest.skipIf(sys.platform != "darwin" and sys.platform != "linux", "Test only runs on Linux and MacOS")
+    @unittest.skipIf(sys.platform == "linux" and not PROCESS_VM_READV_SUPPORTED, "Test only runs on Linux with process_vm_readv support")
+    def test_self_trace(self):
+        stack_trace = get_stack_trace(os.getpid())
+        self.assertEqual(stack_trace[0], "test_self_trace")
+
+if __name__ == "__main__":
+    unittest.main()

Diff for: Modules/Setup

@@ -285,6 +285,7 @@ PYTHONPATH=$(COREPYTHONPATH)
 #_testcapi _testcapimodule.c
 #_testimportmultiple _testimportmultiple.c
 #_testmultiphase _testmultiphase.c
+#_testexternalinspection _testexternalinspection.c
 #_testsinglephase _testsinglephase.c
 
 # ---

Diff for: Modules/Setup.stdlib.in

@@ -171,6 +171,7 @@
 @MODULE__TESTIMPORTMULTIPLE_TRUE@_testimportmultiple _testimportmultiple.c
 @MODULE__TESTMULTIPHASE_TRUE@_testmultiphase _testmultiphase.c
 @MODULE__TESTMULTIPHASE_TRUE@_testsinglephase _testsinglephase.c
+@MODULE__TESTEXTERNALINSPECTION_TRUE@_testexternalinspection _testexternalinspection.c
 @MODULE__CTYPES_TEST_TRUE@_ctypes_test _ctypes/_ctypes_test.c
 
 # Limited API template modules; must be built as shared modules.