| # |
| # Module for starting a process object using os.fork() or CreateProcess() |
| # |
| # multiprocessing/forking.py |
| # |
| # Copyright (c) 2006-2008, R Oudkerk |
| # Licensed to PSF under a Contributor Agreement. |
| # |
| |
| import os |
| import sys |
| import signal |
| |
| from multiprocessing import util, process |
| |
| __all__ = ['Popen', 'assert_spawning', 'duplicate', 'close', 'ForkingPickler'] |
| |
| # |
| # Check that the current thread is spawning a child process |
| # |
| |
| def assert_spawning(self): |
| if not Popen.thread_is_spawning(): |
| raise RuntimeError( |
| '%s objects should only be shared between processes' |
| ' through inheritance' % type(self).__name__ |
| ) |
| |
| # |
| # Try making some callable types picklable |
| # |
| |
| from pickle import Pickler |
| from copyreg import dispatch_table |
| |
| class ForkingPickler(Pickler): |
| _extra_reducers = {} |
| def __init__(self, *args): |
| Pickler.__init__(self, *args) |
| self.dispatch_table = dispatch_table.copy() |
| self.dispatch_table.update(self._extra_reducers) |
| @classmethod |
| def register(cls, type, reduce): |
| cls._extra_reducers[type] = reduce |
| |
| def _reduce_method(m): |
| if m.__self__ is None: |
| return getattr, (m.__class__, m.__func__.__name__) |
| else: |
| return getattr, (m.__self__, m.__func__.__name__) |
| class _C: |
| def f(self): |
| pass |
| ForkingPickler.register(type(_C().f), _reduce_method) |
| |
| |
| def _reduce_method_descriptor(m): |
| return getattr, (m.__objclass__, m.__name__) |
| ForkingPickler.register(type(list.append), _reduce_method_descriptor) |
| ForkingPickler.register(type(int.__add__), _reduce_method_descriptor) |
| |
| try: |
| from functools import partial |
| except ImportError: |
| pass |
| else: |
| def _reduce_partial(p): |
| return _rebuild_partial, (p.func, p.args, p.keywords or {}) |
| def _rebuild_partial(func, args, keywords): |
| return partial(func, *args, **keywords) |
| ForkingPickler.register(partial, _reduce_partial) |
| |
| # |
| # Unix |
| # |
| |
| if sys.platform != 'win32': |
| duplicate = os.dup |
| close = os.close |
| |
| # |
| # We define a Popen class similar to the one from subprocess, but |
| # whose constructor takes a process object as its argument. |
| # |
| |
| class Popen(object): |
| |
| def __init__(self, process_obj): |
| sys.stdout.flush() |
| sys.stderr.flush() |
| self.returncode = None |
| |
| r, w = os.pipe() |
| self.sentinel = r |
| |
| self.pid = os.fork() |
| if self.pid == 0: |
| os.close(r) |
| if 'random' in sys.modules: |
| import random |
| random.seed() |
| code = process_obj._bootstrap() |
| os._exit(code) |
| |
| # `w` will be closed when the child exits, at which point `r` |
| # will become ready for reading (using e.g. select()). |
| os.close(w) |
| util.Finalize(self, os.close, (r,)) |
| |
| def poll(self, flag=os.WNOHANG): |
| if self.returncode is None: |
| try: |
| pid, sts = os.waitpid(self.pid, flag) |
| except os.error: |
| # Child process not yet created. See #1731717 |
| # e.errno == errno.ECHILD == 10 |
| return None |
| if pid == self.pid: |
| if os.WIFSIGNALED(sts): |
| self.returncode = -os.WTERMSIG(sts) |
| else: |
| assert os.WIFEXITED(sts) |
| self.returncode = os.WEXITSTATUS(sts) |
| return self.returncode |
| |
| def wait(self, timeout=None): |
| if self.returncode is None: |
| if timeout is not None: |
| from .connection import wait |
| if not wait([self.sentinel], timeout): |
| return None |
| # This shouldn't block if wait() returned successfully. |
| return self.poll(os.WNOHANG if timeout == 0.0 else 0) |
| return self.returncode |
| |
| def terminate(self): |
| if self.returncode is None: |
| try: |
| os.kill(self.pid, signal.SIGTERM) |
| except OSError: |
| if self.wait(timeout=0.1) is None: |
| raise |
| |
| @staticmethod |
| def thread_is_spawning(): |
| return False |
| |
| # |
| # Windows |
| # |
| |
| else: |
| import _thread |
| import msvcrt |
| import _winapi |
| |
| from pickle import load, HIGHEST_PROTOCOL |
| |
| def dump(obj, file, protocol=None): |
| ForkingPickler(file, protocol).dump(obj) |
| |
| # |
| # |
| # |
| |
| TERMINATE = 0x10000 |
| WINEXE = (sys.platform == 'win32' and getattr(sys, 'frozen', False)) |
| WINSERVICE = sys.executable.lower().endswith("pythonservice.exe") |
| |
| close = _winapi.CloseHandle |
| |
| # |
| # _python_exe is the assumed path to the python executable. |
| # People embedding Python want to modify it. |
| # |
| |
| if WINSERVICE: |
| _python_exe = os.path.join(sys.exec_prefix, 'python.exe') |
| else: |
| _python_exe = sys.executable |
| |
| def set_executable(exe): |
| global _python_exe |
| _python_exe = exe |
| |
| # |
| # |
| # |
| |
| def duplicate(handle, target_process=None, inheritable=False): |
| if target_process is None: |
| target_process = _winapi.GetCurrentProcess() |
| return _winapi.DuplicateHandle( |
| _winapi.GetCurrentProcess(), handle, target_process, |
| 0, inheritable, _winapi.DUPLICATE_SAME_ACCESS |
| ) |
| |
| # |
| # We define a Popen class similar to the one from subprocess, but |
| # whose constructor takes a process object as its argument. |
| # |
| |
| class Popen(object): |
| ''' |
| Start a subprocess to run the code of a process object |
| ''' |
| _tls = _thread._local() |
| |
| def __init__(self, process_obj): |
| cmd = ' '.join('"%s"' % x for x in get_command_line()) |
| prep_data = get_preparation_data(process_obj._name) |
| |
| # create pipe for communication with child |
| rfd, wfd = os.pipe() |
| |
| # get handle for read end of the pipe and make it inheritable |
| rhandle = duplicate(msvcrt.get_osfhandle(rfd), inheritable=True) |
| os.close(rfd) |
| |
| with open(wfd, 'wb', closefd=True) as to_child: |
| # start process |
| try: |
| hp, ht, pid, tid = _winapi.CreateProcess( |
| _python_exe, cmd + (' %s' % rhandle), |
| None, None, 1, 0, None, None, None |
| ) |
| _winapi.CloseHandle(ht) |
| finally: |
| close(rhandle) |
| |
| # set attributes of self |
| self.pid = pid |
| self.returncode = None |
| self._handle = hp |
| self.sentinel = int(hp) |
| |
| # send information to child |
| Popen._tls.process_handle = int(hp) |
| try: |
| dump(prep_data, to_child, HIGHEST_PROTOCOL) |
| dump(process_obj, to_child, HIGHEST_PROTOCOL) |
| finally: |
| del Popen._tls.process_handle |
| |
| @staticmethod |
| def thread_is_spawning(): |
| return getattr(Popen._tls, 'process_handle', None) is not None |
| |
| @staticmethod |
| def duplicate_for_child(handle): |
| return duplicate(handle, Popen._tls.process_handle) |
| |
| def wait(self, timeout=None): |
| if self.returncode is None: |
| if timeout is None: |
| msecs = _winapi.INFINITE |
| else: |
| msecs = max(0, int(timeout * 1000 + 0.5)) |
| |
| res = _winapi.WaitForSingleObject(int(self._handle), msecs) |
| if res == _winapi.WAIT_OBJECT_0: |
| code = _winapi.GetExitCodeProcess(self._handle) |
| if code == TERMINATE: |
| code = -signal.SIGTERM |
| self.returncode = code |
| |
| return self.returncode |
| |
| def poll(self): |
| return self.wait(timeout=0) |
| |
| def terminate(self): |
| if self.returncode is None: |
| try: |
| _winapi.TerminateProcess(int(self._handle), TERMINATE) |
| except OSError: |
| if self.wait(timeout=1.0) is None: |
| raise |
| |
| # |
| # |
| # |
| |
| def is_forking(argv): |
| ''' |
| Return whether commandline indicates we are forking |
| ''' |
| if len(argv) >= 2 and argv[1] == '--multiprocessing-fork': |
| assert len(argv) == 3 |
| return True |
| else: |
| return False |
| |
| |
| def freeze_support(): |
| ''' |
| Run code for process object if this in not the main process |
| ''' |
| if is_forking(sys.argv): |
| main() |
| sys.exit() |
| |
| |
| def get_command_line(): |
| ''' |
| Returns prefix of command line used for spawning a child process |
| ''' |
| if getattr(process.current_process(), '_inheriting', False): |
| raise RuntimeError(''' |
| Attempt to start a new process before the current process |
| has finished its bootstrapping phase. |
| |
| This probably means that you are on Windows and you have |
| forgotten to use the proper idiom in the main module: |
| |
| if __name__ == '__main__': |
| freeze_support() |
| ... |
| |
| The "freeze_support()" line can be omitted if the program |
| is not going to be frozen to produce a Windows executable.''') |
| |
| if getattr(sys, 'frozen', False): |
| return [sys.executable, '--multiprocessing-fork'] |
| else: |
| prog = 'from multiprocessing.forking import main; main()' |
| opts = util._args_from_interpreter_flags() |
| return [_python_exe] + opts + ['-c', prog, '--multiprocessing-fork'] |
| |
| |
| def main(): |
| ''' |
| Run code specifed by data received over pipe |
| ''' |
| assert is_forking(sys.argv) |
| |
| handle = int(sys.argv[-1]) |
| fd = msvcrt.open_osfhandle(handle, os.O_RDONLY) |
| from_parent = os.fdopen(fd, 'rb') |
| |
| process.current_process()._inheriting = True |
| preparation_data = load(from_parent) |
| prepare(preparation_data) |
| self = load(from_parent) |
| process.current_process()._inheriting = False |
| |
| from_parent.close() |
| |
| exitcode = self._bootstrap() |
| sys.exit(exitcode) |
| |
| |
| def get_preparation_data(name): |
| ''' |
| Return info about parent needed by child to unpickle process object |
| ''' |
| from .util import _logger, _log_to_stderr |
| |
| d = dict( |
| name=name, |
| sys_path=sys.path, |
| sys_argv=sys.argv, |
| log_to_stderr=_log_to_stderr, |
| orig_dir=process.ORIGINAL_DIR, |
| authkey=process.current_process().authkey, |
| ) |
| |
| if _logger is not None: |
| d['log_level'] = _logger.getEffectiveLevel() |
| |
| if not WINEXE and not WINSERVICE: |
| main_path = getattr(sys.modules['__main__'], '__file__', None) |
| if not main_path and sys.argv[0] not in ('', '-c'): |
| main_path = sys.argv[0] |
| if main_path is not None: |
| if not os.path.isabs(main_path) and \ |
| process.ORIGINAL_DIR is not None: |
| main_path = os.path.join(process.ORIGINAL_DIR, main_path) |
| d['main_path'] = os.path.normpath(main_path) |
| |
| return d |
| |
| # |
| # Prepare current process |
| # |
| |
| old_main_modules = [] |
| |
| def prepare(data): |
| ''' |
| Try to get current process ready to unpickle process object |
| ''' |
| old_main_modules.append(sys.modules['__main__']) |
| |
| if 'name' in data: |
| process.current_process().name = data['name'] |
| |
| if 'authkey' in data: |
| process.current_process()._authkey = data['authkey'] |
| |
| if 'log_to_stderr' in data and data['log_to_stderr']: |
| util.log_to_stderr() |
| |
| if 'log_level' in data: |
| util.get_logger().setLevel(data['log_level']) |
| |
| if 'sys_path' in data: |
| sys.path = data['sys_path'] |
| |
| if 'sys_argv' in data: |
| sys.argv = data['sys_argv'] |
| |
| if 'dir' in data: |
| os.chdir(data['dir']) |
| |
| if 'orig_dir' in data: |
| process.ORIGINAL_DIR = data['orig_dir'] |
| |
| if 'main_path' in data: |
| # XXX (ncoghlan): The following code makes several bogus |
| # assumptions regarding the relationship between __file__ |
| # and a module's real name. See PEP 302 and issue #10845 |
| main_path = data['main_path'] |
| main_name = os.path.splitext(os.path.basename(main_path))[0] |
| if main_name == '__init__': |
| main_name = os.path.basename(os.path.dirname(main_path)) |
| |
| if main_name == '__main__': |
| main_module = sys.modules['__main__'] |
| main_module.__file__ = main_path |
| elif main_name != 'ipython': |
| # Main modules not actually called __main__.py may |
| # contain additional code that should still be executed |
| import imp |
| |
| if main_path is None: |
| dirs = None |
| elif os.path.basename(main_path).startswith('__init__.py'): |
| dirs = [os.path.dirname(os.path.dirname(main_path))] |
| else: |
| dirs = [os.path.dirname(main_path)] |
| |
| assert main_name not in sys.modules, main_name |
| file, path_name, etc = imp.find_module(main_name, dirs) |
| try: |
| # We would like to do "imp.load_module('__main__', ...)" |
| # here. However, that would cause 'if __name__ == |
| # "__main__"' clauses to be executed. |
| main_module = imp.load_module( |
| '__parents_main__', file, path_name, etc |
| ) |
| finally: |
| if file: |
| file.close() |
| |
| sys.modules['__main__'] = main_module |
| main_module.__name__ = '__main__' |
| |
| # Try to make the potentially picklable objects in |
| # sys.modules['__main__'] realize they are in the main |
| # module -- somewhat ugly. |
| for obj in list(main_module.__dict__.values()): |
| try: |
| if obj.__module__ == '__parents_main__': |
| obj.__module__ = '__main__' |
| except Exception: |
| pass |