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Diffstat (limited to 'lib/ansible/module_utils/compat/_selectors2.py')
| -rw-r--r-- | lib/ansible/module_utils/compat/_selectors2.py | 655 |
1 files changed, 655 insertions, 0 deletions
diff --git a/lib/ansible/module_utils/compat/_selectors2.py b/lib/ansible/module_utils/compat/_selectors2.py new file mode 100644 index 0000000..be44b4b --- /dev/null +++ b/lib/ansible/module_utils/compat/_selectors2.py @@ -0,0 +1,655 @@ +# This file is from the selectors2.py package. It backports the PSF Licensed +# selectors module from the Python-3.5 stdlib to older versions of Python. +# The author, Seth Michael Larson, dual licenses his modifications under the +# PSF License and MIT License: +# https://github.com/SethMichaelLarson/selectors2#license +# +# Copyright (c) 2016 Seth Michael Larson +# +# PSF License (see licenses/PSF-license.txt or https://opensource.org/licenses/Python-2.0) +# MIT License (see licenses/MIT-license.txt or https://opensource.org/licenses/MIT) +# + + +# Backport of selectors.py from Python 3.5+ to support Python < 3.4 +# Also has the behavior specified in PEP 475 which is to retry syscalls +# in the case of an EINTR error. This module is required because selectors34 +# does not follow this behavior and instead returns that no file descriptor +# events have occurred rather than retry the syscall. The decision to drop +# support for select.devpoll is made to maintain 100% test coverage. + +import errno +import math +import select +import socket +import sys +import time +from collections import namedtuple +from ansible.module_utils.common._collections_compat import Mapping + +try: + monotonic = time.monotonic +except (AttributeError, ImportError): # Python 3.3< + monotonic = time.time + +__author__ = 'Seth Michael Larson' +__email__ = 'sethmichaellarson@protonmail.com' +__version__ = '1.1.1' +__license__ = 'MIT' + +__all__ = [ + 'EVENT_READ', + 'EVENT_WRITE', + 'SelectorError', + 'SelectorKey', + 'DefaultSelector' +] + +EVENT_READ = (1 << 0) +EVENT_WRITE = (1 << 1) + +HAS_SELECT = True # Variable that shows whether the platform has a selector. +_SYSCALL_SENTINEL = object() # Sentinel in case a system call returns None. + + +class SelectorError(Exception): + def __init__(self, errcode): + super(SelectorError, self).__init__() + self.errno = errcode + + def __repr__(self): + return "<SelectorError errno={0}>".format(self.errno) + + def __str__(self): + return self.__repr__() + + +def _fileobj_to_fd(fileobj): + """ Return a file descriptor from a file object. If + given an integer will simply return that integer back. """ + if isinstance(fileobj, int): + fd = fileobj + else: + try: + fd = int(fileobj.fileno()) + except (AttributeError, TypeError, ValueError): + raise ValueError("Invalid file object: {0!r}".format(fileobj)) + if fd < 0: + raise ValueError("Invalid file descriptor: {0}".format(fd)) + return fd + + +# Python 3.5 uses a more direct route to wrap system calls to increase speed. +if sys.version_info >= (3, 5): + def _syscall_wrapper(func, _, *args, **kwargs): + """ This is the short-circuit version of the below logic + because in Python 3.5+ all selectors restart system calls. """ + try: + return func(*args, **kwargs) + except (OSError, IOError, select.error) as e: + errcode = None + if hasattr(e, "errno"): + errcode = e.errno + elif hasattr(e, "args"): + errcode = e.args[0] + raise SelectorError(errcode) +else: + def _syscall_wrapper(func, recalc_timeout, *args, **kwargs): + """ Wrapper function for syscalls that could fail due to EINTR. + All functions should be retried if there is time left in the timeout + in accordance with PEP 475. """ + timeout = kwargs.get("timeout", None) + if timeout is None: + expires = None + recalc_timeout = False + else: + timeout = float(timeout) + if timeout < 0.0: # Timeout less than 0 treated as no timeout. + expires = None + else: + expires = monotonic() + timeout + + args = list(args) + if recalc_timeout and "timeout" not in kwargs: + raise ValueError( + "Timeout must be in args or kwargs to be recalculated") + + result = _SYSCALL_SENTINEL + while result is _SYSCALL_SENTINEL: + try: + result = func(*args, **kwargs) + # OSError is thrown by select.select + # IOError is thrown by select.epoll.poll + # select.error is thrown by select.poll.poll + # Aren't we thankful for Python 3.x rework for exceptions? + except (OSError, IOError, select.error) as e: + # select.error wasn't a subclass of OSError in the past. + errcode = None + if hasattr(e, "errno"): + errcode = e.errno + elif hasattr(e, "args"): + errcode = e.args[0] + + # Also test for the Windows equivalent of EINTR. + is_interrupt = (errcode == errno.EINTR or (hasattr(errno, "WSAEINTR") and + errcode == errno.WSAEINTR)) + + if is_interrupt: + if expires is not None: + current_time = monotonic() + if current_time > expires: + raise OSError(errno.ETIMEDOUT) + if recalc_timeout: + if "timeout" in kwargs: + kwargs["timeout"] = expires - current_time + continue + if errcode: + raise SelectorError(errcode) + else: + raise + return result + + +SelectorKey = namedtuple('SelectorKey', ['fileobj', 'fd', 'events', 'data']) + + +class _SelectorMapping(Mapping): + """ Mapping of file objects to selector keys """ + + def __init__(self, selector): + self._selector = selector + + def __len__(self): + return len(self._selector._fd_to_key) + + def __getitem__(self, fileobj): + try: + fd = self._selector._fileobj_lookup(fileobj) + return self._selector._fd_to_key[fd] + except KeyError: + raise KeyError("{0!r} is not registered.".format(fileobj)) + + def __iter__(self): + return iter(self._selector._fd_to_key) + + +class BaseSelector(object): + """ Abstract Selector class + + A selector supports registering file objects to be monitored + for specific I/O events. + + A file object is a file descriptor or any object with a + `fileno()` method. An arbitrary object can be attached to the + file object which can be used for example to store context info, + a callback, etc. + + A selector can use various implementations (select(), poll(), epoll(), + and kqueue()) depending on the platform. The 'DefaultSelector' class uses + the most efficient implementation for the current platform. + """ + def __init__(self): + # Maps file descriptors to keys. + self._fd_to_key = {} + + # Read-only mapping returned by get_map() + self._map = _SelectorMapping(self) + + def _fileobj_lookup(self, fileobj): + """ Return a file descriptor from a file object. + This wraps _fileobj_to_fd() to do an exhaustive + search in case the object is invalid but we still + have it in our map. Used by unregister() so we can + unregister an object that was previously registered + even if it is closed. It is also used by _SelectorMapping + """ + try: + return _fileobj_to_fd(fileobj) + except ValueError: + + # Search through all our mapped keys. + for key in self._fd_to_key.values(): + if key.fileobj is fileobj: + return key.fd + + # Raise ValueError after all. + raise + + def register(self, fileobj, events, data=None): + """ Register a file object for a set of events to monitor. """ + if (not events) or (events & ~(EVENT_READ | EVENT_WRITE)): + raise ValueError("Invalid events: {0!r}".format(events)) + + key = SelectorKey(fileobj, self._fileobj_lookup(fileobj), events, data) + + if key.fd in self._fd_to_key: + raise KeyError("{0!r} (FD {1}) is already registered" + .format(fileobj, key.fd)) + + self._fd_to_key[key.fd] = key + return key + + def unregister(self, fileobj): + """ Unregister a file object from being monitored. """ + try: + key = self._fd_to_key.pop(self._fileobj_lookup(fileobj)) + except KeyError: + raise KeyError("{0!r} is not registered".format(fileobj)) + + # Getting the fileno of a closed socket on Windows errors with EBADF. + except socket.error as err: + if err.errno != errno.EBADF: + raise + else: + for key in self._fd_to_key.values(): + if key.fileobj is fileobj: + self._fd_to_key.pop(key.fd) + break + else: + raise KeyError("{0!r} is not registered".format(fileobj)) + return key + + def modify(self, fileobj, events, data=None): + """ Change a registered file object monitored events and data. """ + # NOTE: Some subclasses optimize this operation even further. + try: + key = self._fd_to_key[self._fileobj_lookup(fileobj)] + except KeyError: + raise KeyError("{0!r} is not registered".format(fileobj)) + + if events != key.events: + self.unregister(fileobj) + key = self.register(fileobj, events, data) + + elif data != key.data: + # Use a shortcut to update the data. + key = key._replace(data=data) + self._fd_to_key[key.fd] = key + + return key + + def select(self, timeout=None): + """ Perform the actual selection until some monitored file objects + are ready or the timeout expires. """ + raise NotImplementedError() + + def close(self): + """ Close the selector. This must be called to ensure that all + underlying resources are freed. """ + self._fd_to_key.clear() + self._map = None + + def get_key(self, fileobj): + """ Return the key associated with a registered file object. """ + mapping = self.get_map() + if mapping is None: + raise RuntimeError("Selector is closed") + try: + return mapping[fileobj] + except KeyError: + raise KeyError("{0!r} is not registered".format(fileobj)) + + def get_map(self): + """ Return a mapping of file objects to selector keys """ + return self._map + + def _key_from_fd(self, fd): + """ Return the key associated to a given file descriptor + Return None if it is not found. """ + try: + return self._fd_to_key[fd] + except KeyError: + return None + + def __enter__(self): + return self + + def __exit__(self, *args): + self.close() + + +# Almost all platforms have select.select() +if hasattr(select, "select"): + class SelectSelector(BaseSelector): + """ Select-based selector. """ + def __init__(self): + super(SelectSelector, self).__init__() + self._readers = set() + self._writers = set() + + def register(self, fileobj, events, data=None): + key = super(SelectSelector, self).register(fileobj, events, data) + if events & EVENT_READ: + self._readers.add(key.fd) + if events & EVENT_WRITE: + self._writers.add(key.fd) + return key + + def unregister(self, fileobj): + key = super(SelectSelector, self).unregister(fileobj) + self._readers.discard(key.fd) + self._writers.discard(key.fd) + return key + + def _select(self, r, w, timeout=None): + """ Wrapper for select.select because timeout is a positional arg """ + return select.select(r, w, [], timeout) + + def select(self, timeout=None): + # Selecting on empty lists on Windows errors out. + if not len(self._readers) and not len(self._writers): + return [] + + timeout = None if timeout is None else max(timeout, 0.0) + ready = [] + r, w, _ = _syscall_wrapper(self._select, True, self._readers, + self._writers, timeout=timeout) + r = set(r) + w = set(w) + for fd in r | w: + events = 0 + if fd in r: + events |= EVENT_READ + if fd in w: + events |= EVENT_WRITE + + key = self._key_from_fd(fd) + if key: + ready.append((key, events & key.events)) + return ready + + __all__.append('SelectSelector') + + +if hasattr(select, "poll"): + class PollSelector(BaseSelector): + """ Poll-based selector """ + def __init__(self): + super(PollSelector, self).__init__() + self._poll = select.poll() + + def register(self, fileobj, events, data=None): + key = super(PollSelector, self).register(fileobj, events, data) + event_mask = 0 + if events & EVENT_READ: + event_mask |= select.POLLIN + if events & EVENT_WRITE: + event_mask |= select.POLLOUT + self._poll.register(key.fd, event_mask) + return key + + def unregister(self, fileobj): + key = super(PollSelector, self).unregister(fileobj) + self._poll.unregister(key.fd) + return key + + def _wrap_poll(self, timeout=None): + """ Wrapper function for select.poll.poll() so that + _syscall_wrapper can work with only seconds. """ + if timeout is not None: + if timeout <= 0: + timeout = 0 + else: + # select.poll.poll() has a resolution of 1 millisecond, + # round away from zero to wait *at least* timeout seconds. + timeout = math.ceil(timeout * 1e3) + + result = self._poll.poll(timeout) + return result + + def select(self, timeout=None): + ready = [] + fd_events = _syscall_wrapper(self._wrap_poll, True, timeout=timeout) + for fd, event_mask in fd_events: + events = 0 + if event_mask & ~select.POLLIN: + events |= EVENT_WRITE + if event_mask & ~select.POLLOUT: + events |= EVENT_READ + + key = self._key_from_fd(fd) + if key: + ready.append((key, events & key.events)) + + return ready + + __all__.append('PollSelector') + +if hasattr(select, "epoll"): + class EpollSelector(BaseSelector): + """ Epoll-based selector """ + def __init__(self): + super(EpollSelector, self).__init__() + self._epoll = select.epoll() + + def fileno(self): + return self._epoll.fileno() + + def register(self, fileobj, events, data=None): + key = super(EpollSelector, self).register(fileobj, events, data) + events_mask = 0 + if events & EVENT_READ: + events_mask |= select.EPOLLIN + if events & EVENT_WRITE: + events_mask |= select.EPOLLOUT + _syscall_wrapper(self._epoll.register, False, key.fd, events_mask) + return key + + def unregister(self, fileobj): + key = super(EpollSelector, self).unregister(fileobj) + try: + _syscall_wrapper(self._epoll.unregister, False, key.fd) + except SelectorError: + # This can occur when the fd was closed since registry. + pass + return key + + def select(self, timeout=None): + if timeout is not None: + if timeout <= 0: + timeout = 0.0 + else: + # select.epoll.poll() has a resolution of 1 millisecond + # but luckily takes seconds so we don't need a wrapper + # like PollSelector. Just for better rounding. + timeout = math.ceil(timeout * 1e3) * 1e-3 + timeout = float(timeout) + else: + timeout = -1.0 # epoll.poll() must have a float. + + # We always want at least 1 to ensure that select can be called + # with no file descriptors registered. Otherwise will fail. + max_events = max(len(self._fd_to_key), 1) + + ready = [] + fd_events = _syscall_wrapper(self._epoll.poll, True, + timeout=timeout, + maxevents=max_events) + for fd, event_mask in fd_events: + events = 0 + if event_mask & ~select.EPOLLIN: + events |= EVENT_WRITE + if event_mask & ~select.EPOLLOUT: + events |= EVENT_READ + + key = self._key_from_fd(fd) + if key: + ready.append((key, events & key.events)) + return ready + + def close(self): + self._epoll.close() + super(EpollSelector, self).close() + + __all__.append('EpollSelector') + + +if hasattr(select, "devpoll"): + class DevpollSelector(BaseSelector): + """Solaris /dev/poll selector.""" + + def __init__(self): + super(DevpollSelector, self).__init__() + self._devpoll = select.devpoll() + + def fileno(self): + return self._devpoll.fileno() + + def register(self, fileobj, events, data=None): + key = super(DevpollSelector, self).register(fileobj, events, data) + poll_events = 0 + if events & EVENT_READ: + poll_events |= select.POLLIN + if events & EVENT_WRITE: + poll_events |= select.POLLOUT + self._devpoll.register(key.fd, poll_events) + return key + + def unregister(self, fileobj): + key = super(DevpollSelector, self).unregister(fileobj) + self._devpoll.unregister(key.fd) + return key + + def _wrap_poll(self, timeout=None): + """ Wrapper function for select.poll.poll() so that + _syscall_wrapper can work with only seconds. """ + if timeout is not None: + if timeout <= 0: + timeout = 0 + else: + # select.devpoll.poll() has a resolution of 1 millisecond, + # round away from zero to wait *at least* timeout seconds. + timeout = math.ceil(timeout * 1e3) + + result = self._devpoll.poll(timeout) + return result + + def select(self, timeout=None): + ready = [] + fd_events = _syscall_wrapper(self._wrap_poll, True, timeout=timeout) + for fd, event_mask in fd_events: + events = 0 + if event_mask & ~select.POLLIN: + events |= EVENT_WRITE + if event_mask & ~select.POLLOUT: + events |= EVENT_READ + + key = self._key_from_fd(fd) + if key: + ready.append((key, events & key.events)) + + return ready + + def close(self): + self._devpoll.close() + super(DevpollSelector, self).close() + + __all__.append('DevpollSelector') + + +if hasattr(select, "kqueue"): + class KqueueSelector(BaseSelector): + """ Kqueue / Kevent-based selector """ + def __init__(self): + super(KqueueSelector, self).__init__() + self._kqueue = select.kqueue() + + def fileno(self): + return self._kqueue.fileno() + + def register(self, fileobj, events, data=None): + key = super(KqueueSelector, self).register(fileobj, events, data) + if events & EVENT_READ: + kevent = select.kevent(key.fd, + select.KQ_FILTER_READ, + select.KQ_EV_ADD) + + _syscall_wrapper(self._wrap_control, False, [kevent], 0, 0) + + if events & EVENT_WRITE: + kevent = select.kevent(key.fd, + select.KQ_FILTER_WRITE, + select.KQ_EV_ADD) + + _syscall_wrapper(self._wrap_control, False, [kevent], 0, 0) + + return key + + def unregister(self, fileobj): + key = super(KqueueSelector, self).unregister(fileobj) + if key.events & EVENT_READ: + kevent = select.kevent(key.fd, + select.KQ_FILTER_READ, + select.KQ_EV_DELETE) + try: + _syscall_wrapper(self._wrap_control, False, [kevent], 0, 0) + except SelectorError: + pass + if key.events & EVENT_WRITE: + kevent = select.kevent(key.fd, + select.KQ_FILTER_WRITE, + select.KQ_EV_DELETE) + try: + _syscall_wrapper(self._wrap_control, False, [kevent], 0, 0) + except SelectorError: + pass + + return key + + def select(self, timeout=None): + if timeout is not None: + timeout = max(timeout, 0) + + max_events = len(self._fd_to_key) * 2 + ready_fds = {} + + kevent_list = _syscall_wrapper(self._wrap_control, True, + None, max_events, timeout=timeout) + + for kevent in kevent_list: + fd = kevent.ident + event_mask = kevent.filter + events = 0 + if event_mask == select.KQ_FILTER_READ: + events |= EVENT_READ + if event_mask == select.KQ_FILTER_WRITE: + events |= EVENT_WRITE + + key = self._key_from_fd(fd) + if key: + if key.fd not in ready_fds: + ready_fds[key.fd] = (key, events & key.events) + else: + old_events = ready_fds[key.fd][1] + ready_fds[key.fd] = (key, (events | old_events) & key.events) + + return list(ready_fds.values()) + + def close(self): + self._kqueue.close() + super(KqueueSelector, self).close() + + def _wrap_control(self, changelist, max_events, timeout): + return self._kqueue.control(changelist, max_events, timeout) + + __all__.append('KqueueSelector') + + +# Choose the best implementation, roughly: +# kqueue == epoll == devpoll > poll > select. +# select() also can't accept a FD > FD_SETSIZE (usually around 1024) +if 'KqueueSelector' in globals(): # Platform-specific: Mac OS and BSD + DefaultSelector = KqueueSelector +elif 'DevpollSelector' in globals(): + DefaultSelector = DevpollSelector +elif 'EpollSelector' in globals(): # Platform-specific: Linux + DefaultSelector = EpollSelector +elif 'PollSelector' in globals(): # Platform-specific: Linux + DefaultSelector = PollSelector +elif 'SelectSelector' in globals(): # Platform-specific: Windows + DefaultSelector = SelectSelector +else: # Platform-specific: AppEngine + def no_selector(_): + raise ValueError("Platform does not have a selector") + DefaultSelector = no_selector + HAS_SELECT = False |