From 4dea06531ece28dffc1452de2694fb22e99b45f9 Mon Sep 17 00:00:00 2001 From: Victor Stinner Date: Fri, 11 Aug 2017 14:38:37 +0200 Subject: [PATCH] bpo-31173: Rewrite WSTOPSIG test of test_subprocess (#3055) (#3071) The current test_child_terminated_in_stopped_state() function test creates a child process which calls ptrace(PTRACE_TRACEME, 0, 0) and then crash (SIGSEGV). The problem is that calling os.waitpid() in the parent process is not enough to close the process: the child process remains alive and so the unit test leaks a child process in a strange state. Closing the child process requires non-trivial code, maybe platform specific. Remove the functional test and replaces it with an unit test which mocks os.waitpid() using a new _testcapi.W_STOPCODE() function to test the WIFSTOPPED() path. (cherry picked from commit 7b7c6dcfff6a35333988a3c74c895ed19dff2e09) --- Lib/test/test_subprocess.py | 59 ++++++++++++++++--------------------- Modules/_testcapimodule.c | 22 ++++++++++++++ 2 files changed, 48 insertions(+), 33 deletions(-) diff --git a/Lib/test/test_subprocess.py b/Lib/test/test_subprocess.py index 77633376eb..ce3372354c 100644 --- a/Lib/test/test_subprocess.py +++ b/Lib/test/test_subprocess.py @@ -28,6 +28,11 @@ try: except ImportError: threading = None +try: + import _testcapi +except ImportError: + _testcapi = None + mswindows = (sys.platform == "win32") # @@ -1265,40 +1270,28 @@ class POSIXProcessTestCase(BaseTestCase): self.assertEqual(p2.returncode, 0, "Unexpected error: " + repr(stderr)) - @unittest.skipIf(not ctypes, 'ctypes module required') - @unittest.skipIf(not sys.executable, 'Test requires sys.executable') - def test_child_terminated_in_stopped_state(self): + @unittest.skipUnless(_testcapi is not None + and hasattr(_testcapi, 'W_STOPCODE'), + 'need _testcapi.W_STOPCODE') + def test_stopped(self): """Test wait() behavior when waitpid returns WIFSTOPPED; issue29335.""" - PTRACE_TRACEME = 0 # From glibc and MacOS (PT_TRACE_ME). - libc_name = ctypes.util.find_library('c') - libc = ctypes.CDLL(libc_name) - if not hasattr(libc, 'ptrace'): - raise unittest.SkipTest('ptrace() required') - - code = textwrap.dedent(""" - import ctypes - from test.support import _crash_python - - libc = ctypes.CDLL({libc_name!r}) - libc.ptrace({PTRACE_TRACEME}, 0, 0) - """.format(libc_name=libc_name, PTRACE_TRACEME=PTRACE_TRACEME)) - - child = subprocess.Popen([sys.executable, '-c', code]) - if child.wait() != 0: - raise unittest.SkipTest('ptrace() failed - unable to test') - - code += textwrap.dedent(""" - # Crash the process - _crash_python() - """) - child = subprocess.Popen([sys.executable, '-c', code]) - try: - returncode = child.wait() - except: - child.kill() # Clean up the hung stopped process. - raise - self.assertNotEqual(0, returncode) - self.assertLess(returncode, 0) # signal death, likely SIGSEGV. + args = [sys.executable, '-c', 'pass'] + proc = subprocess.Popen(args) + + # Wait until the real process completes to avoid zombie process + pid = proc.pid + pid, status = os.waitpid(pid, 0) + self.assertEqual(status, 0) + + status = _testcapi.W_STOPCODE(3) + + def mock_waitpid(pid, flags): + return (pid, status) + + with test_support.swap_attr(os, 'waitpid', mock_waitpid): + returncode = proc.wait() + + self.assertEqual(returncode, -3) @unittest.skipUnless(mswindows, "Windows specific tests") diff --git a/Modules/_testcapimodule.c b/Modules/_testcapimodule.c index a68d839a7f..a5e3f07667 100644 --- a/Modules/_testcapimodule.c +++ b/Modules/_testcapimodule.c @@ -15,6 +15,10 @@ # include #endif +#ifdef HAVE_SYS_WAIT_H +#include /* For W_STOPCODE */ +#endif + #ifdef WITH_THREAD #include "pythread.h" #endif /* WITH_THREAD */ @@ -2523,6 +2527,7 @@ msvcrt_CrtSetReportMode(PyObject* self, PyObject *args) return PyInt_FromLong(res); } + static PyObject* msvcrt_CrtSetReportFile(PyObject* self, PyObject *args) { @@ -2540,6 +2545,20 @@ msvcrt_CrtSetReportFile(PyObject* self, PyObject *args) #endif +#ifdef W_STOPCODE +static PyObject* +py_w_stopcode(PyObject *self, PyObject *args) +{ + int sig, status; + if (!PyArg_ParseTuple(args, "i", &sig)) { + return NULL; + } + status = W_STOPCODE(sig); + return PyLong_FromLong(status); +} +#endif + + static PyMethodDef TestMethods[] = { {"raise_exception", raise_exception, METH_VARARGS}, {"set_errno", set_errno, METH_VARARGS}, @@ -2655,6 +2674,9 @@ static PyMethodDef TestMethods[] = { #ifdef MS_WINDOWS {"CrtSetReportMode", (PyCFunction)msvcrt_CrtSetReportMode, METH_VARARGS}, {"CrtSetReportFile", (PyCFunction)msvcrt_CrtSetReportFile, METH_VARARGS}, +#endif +#ifdef W_STOPCODE + {"W_STOPCODE", py_w_stopcode, METH_VARARGS}, #endif {NULL, NULL} /* sentinel */ }; -- 2.50.1