diff --git a/Lib/subprocess.py b/Lib/subprocess.py index c5128d857aa..6e0cf06637a 100644 --- a/Lib/subprocess.py +++ b/Lib/subprocess.py @@ -397,39 +397,14 @@ if mswindows: else: import select _has_poll = hasattr(select, 'poll') - import fcntl - import pickle - - try: - import _posixsubprocess - except ImportError: - _posixsubprocess = None - warnings.warn("The _posixsubprocess module is not being used. " - "Child process reliability may suffer if your " - "program uses threads.", RuntimeWarning) + import _posixsubprocess + _create_pipe = _posixsubprocess.cloexec_pipe # When select or poll has indicated that the file is writable, # we can write up to _PIPE_BUF bytes without risk of blocking. # POSIX defines PIPE_BUF as >= 512. _PIPE_BUF = getattr(select, 'PIPE_BUF', 512) - _FD_CLOEXEC = getattr(fcntl, 'FD_CLOEXEC', 1) - - def _set_cloexec(fd, cloexec): - old = fcntl.fcntl(fd, fcntl.F_GETFD) - if cloexec: - fcntl.fcntl(fd, fcntl.F_SETFD, old | _FD_CLOEXEC) - else: - fcntl.fcntl(fd, fcntl.F_SETFD, old & ~_FD_CLOEXEC) - - if _posixsubprocess: - _create_pipe = _posixsubprocess.cloexec_pipe - else: - def _create_pipe(): - fds = os.pipe() - _set_cloexec(fds[0], True) - _set_cloexec(fds[1], True) - return fds __all__ = ["Popen", "PIPE", "STDOUT", "call", "check_call", "getstatusoutput", "getoutput", "check_output", "CalledProcessError", "DEVNULL"] @@ -1267,140 +1242,33 @@ class Popen(object): errpipe_read, errpipe_write = _create_pipe() try: try: + # We must avoid complex work that could involve + # malloc or free in the child process to avoid + # potential deadlocks, thus we do all this here. + # and pass it to fork_exec() - if _posixsubprocess: - # We must avoid complex work that could involve - # malloc or free in the child process to avoid - # potential deadlocks, thus we do all this here. - # and pass it to fork_exec() - - if env: - env_list = [os.fsencode(k) + b'=' + os.fsencode(v) - for k, v in env.items()] - else: - env_list = None # Use execv instead of execve. - executable = os.fsencode(executable) - if os.path.dirname(executable): - executable_list = (executable,) - else: - # This matches the behavior of os._execvpe(). - executable_list = tuple( - os.path.join(os.fsencode(dir), executable) - for dir in os.get_exec_path(env)) - fds_to_keep = set(pass_fds) - fds_to_keep.add(errpipe_write) - self.pid = _posixsubprocess.fork_exec( - args, executable_list, - close_fds, sorted(fds_to_keep), cwd, env_list, - p2cread, p2cwrite, c2pread, c2pwrite, - errread, errwrite, - errpipe_read, errpipe_write, - restore_signals, start_new_session, preexec_fn) + if env: + env_list = [os.fsencode(k) + b'=' + os.fsencode(v) + for k, v in env.items()] else: - # Pure Python implementation: It is not thread safe. - # This implementation may deadlock in the child if your - # parent process has any other threads running. - - gc_was_enabled = gc.isenabled() - # Disable gc to avoid bug where gc -> file_dealloc -> - # write to stderr -> hang. See issue1336 - gc.disable() - try: - self.pid = os.fork() - except: - if gc_was_enabled: - gc.enable() - raise - self._child_created = True - if self.pid == 0: - # Child - try: - # Close parent's pipe ends - if p2cwrite != -1: - os.close(p2cwrite) - if c2pread != -1: - os.close(c2pread) - if errread != -1: - os.close(errread) - os.close(errpipe_read) - - # Dup fds for child - def _dup2(a, b): - # dup2() removes the CLOEXEC flag but - # we must do it ourselves if dup2() - # would be a no-op (issue #10806). - if a == b: - _set_cloexec(a, False) - elif a != -1: - os.dup2(a, b) - _dup2(p2cread, 0) - _dup2(c2pwrite, 1) - _dup2(errwrite, 2) - - # Close pipe fds. Make sure we don't close the - # same fd more than once, or standard fds. - closed = set() - for fd in [p2cread, c2pwrite, errwrite]: - if fd > 2 and fd not in closed: - os.close(fd) - closed.add(fd) - - # Close all other fds, if asked for - if close_fds: - fds_to_keep = set(pass_fds) - fds_to_keep.add(errpipe_write) - self._close_fds(fds_to_keep) - - - if cwd is not None: - os.chdir(cwd) - - # This is a copy of Python/pythonrun.c - # _Py_RestoreSignals(). If that were exposed - # as a sys._py_restoresignals func it would be - # better.. but this pure python implementation - # isn't likely to be used much anymore. - if restore_signals: - signals = ('SIGPIPE', 'SIGXFZ', 'SIGXFSZ') - for sig in signals: - if hasattr(signal, sig): - signal.signal(getattr(signal, sig), - signal.SIG_DFL) - - if start_new_session and hasattr(os, 'setsid'): - os.setsid() - - if preexec_fn: - preexec_fn() - - if env is None: - os.execvp(executable, args) - else: - os.execvpe(executable, args, env) - - except: - try: - exc_type, exc_value = sys.exc_info()[:2] - if isinstance(exc_value, OSError): - errno_num = exc_value.errno - else: - errno_num = 0 - message = '%s:%x:%s' % (exc_type.__name__, - errno_num, exc_value) - message = message.encode(errors="surrogatepass") - os.write(errpipe_write, message) - except Exception: - # We MUST not allow anything odd happening - # above to prevent us from exiting below. - pass - - # This exitcode won't be reported to applications - # so it really doesn't matter what we return. - os._exit(255) - - # Parent - if gc_was_enabled: - gc.enable() + env_list = None # Use execv instead of execve. + executable = os.fsencode(executable) + if os.path.dirname(executable): + executable_list = (executable,) + else: + # This matches the behavior of os._execvpe(). + executable_list = tuple( + os.path.join(os.fsencode(dir), executable) + for dir in os.get_exec_path(env)) + fds_to_keep = set(pass_fds) + fds_to_keep.add(errpipe_write) + self.pid = _posixsubprocess.fork_exec( + args, executable_list, + close_fds, sorted(fds_to_keep), cwd, env_list, + p2cread, p2cwrite, c2pread, c2pwrite, + errread, errwrite, + errpipe_read, errpipe_write, + restore_signals, start_new_session, preexec_fn) finally: # be sure the FD is closed no matter what os.close(errpipe_write) diff --git a/Lib/test/test_subprocess.py b/Lib/test/test_subprocess.py index 08d2653102c..99d7a924e8e 100644 --- a/Lib/test/test_subprocess.py +++ b/Lib/test/test_subprocess.py @@ -1495,28 +1495,6 @@ class ProcessTestCaseNoPoll(ProcessTestCase): ProcessTestCase.tearDown(self) -@unittest.skipUnless(getattr(subprocess, '_posixsubprocess', False), - "_posixsubprocess extension module not found.") -class ProcessTestCasePOSIXPurePython(ProcessTestCase, POSIXProcessTestCase): - @classmethod - def setUpClass(cls): - global subprocess - assert subprocess._posixsubprocess - # Reimport subprocess while forcing _posixsubprocess to not exist. - with support.check_warnings(('.*_posixsubprocess .* not being used.*', - RuntimeWarning)): - subprocess = support.import_fresh_module( - 'subprocess', blocked=['_posixsubprocess']) - assert not subprocess._posixsubprocess - - @classmethod - def tearDownClass(cls): - global subprocess - # Reimport subprocess as it should be, restoring order to the universe. - subprocess = support.import_fresh_module('subprocess') - assert subprocess._posixsubprocess - - class HelperFunctionTests(unittest.TestCase): @unittest.skipIf(mswindows, "errno and EINTR make no sense on windows") def test_eintr_retry_call(self):