/gevent/socket.py

# Copyright (c) 2005-2006, Bob Ippolito
# Copyright (c) 2007, Linden Research, Inc.
# Copyright (c) 2009-2012 Denis Bilenko
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.

"""Cooperative socket module.

This module provides socket operations and some related functions.
The API of the functions and classes matches the API of the corresponding
items in standard :mod:`socket` module exactly, but the synchronous functions
in this module only block the current greenlet and let the others run.

For convenience, exceptions (like :class:`error <socket.error>` and :class:`timeout <socket.timeout>`)
as well as the constants from :mod:`socket` module are imported into this module.
"""

from __future__ import absolute_import

# standard functions and classes that this module re-implements in a gevent-aware way:
__implements__ = ['create_connection',
                  'socket',
                  'SocketType',
                  'fromfd',
                  'socketpair']

__dns__ = ['getaddrinfo',
           'gethostbyname',
           'gethostbyname_ex',
           'gethostbyaddr',
           'getnameinfo',
           'getfqdn']

__implements__ += __dns__

# non-standard functions that this module provides:
__extensions__ = ['wait_read',
                  'wait_write',
                  'wait_readwrite']

# standard functions and classes that this module re-imports
__imports__ = ['error',
               'gaierror',
               'herror',
               'htonl',
               'htons',
               'ntohl',
               'ntohs',
               'inet_aton',
               'inet_ntoa',
               'inet_pton',
               'inet_ntop',
               'timeout',
               'gethostname',
               'getprotobyname',
               'getservbyname',
               'getservbyport',
               'getdefaulttimeout',
               'setdefaulttimeout',
               # Python 2.5 and older:
               'RAND_add',
               'RAND_egd',
               'RAND_status',
               # Windows:
               'errorTab']


import sys
import time
from gevent.hub import get_hub, string_types, integer_types
from gevent.timeout import Timeout

is_windows = sys.platform == 'win32'

if is_windows:
    # no such thing as WSAEPERM or error code 10001 according to winsock.h or MSDN
    from errno import WSAEINVAL as EINVAL
    from errno import WSAEWOULDBLOCK as EWOULDBLOCK
    from errno import WSAEINPROGRESS as EINPROGRESS
    from errno import WSAEALREADY as EALREADY
    from errno import WSAEISCONN as EISCONN
    from gevent.win32util import formatError as strerror
    EAGAIN = EWOULDBLOCK
else:
    from errno import EINVAL
    from errno import EWOULDBLOCK
    from errno import EINPROGRESS
    from errno import EALREADY
    from errno import EAGAIN
    from errno import EISCONN
    from os import strerror

try:
    from errno import EBADF
except ImportError:
    EBADF = 9

import _socket
_realsocket = _socket.socket
import socket as __socket__
_fileobject = __socket__._fileobject

for name in __imports__[:]:
    try:
        value = getattr(__socket__, name)
        globals()[name] = value
    except AttributeError:
        __imports__.remove(name)

for name in __socket__.__all__:
    value = getattr(__socket__, name)
    if isinstance(value, integer_types) or isinstance(value, string_types):
        globals()[name] = value
        __imports__.append(name)

del name, value


def wait(io, timeout=None, timeout_exc=timeout('timed out')):
    """Block the current greenlet until *io* is ready.

    If *timeout* is non-negative, then *timeout_exc* is raised after *timeout* second has passed.
    By default *timeout_exc* is ``socket.timeout('timed out')``.

    If :func:`cancel_wait` is called, raise ``socket.error(EBADF, 'File descriptor was closed in another greenlet')``.
    """
    assert io.callback is None, 'This socket is already used by another greenlet: %r' % (io.callback, )
    if timeout is not None:
        timeout = Timeout.start_new(timeout, timeout_exc)
    try:
        return get_hub().wait(io)
    finally:
        if timeout is not None:
            timeout.cancel()
    # rename "io" to "watcher" because wait() works with any watcher


def wait_read(fileno, timeout=None, timeout_exc=timeout('timed out')):
    """Block the current greenlet until *fileno* is ready to read.

    If *timeout* is non-negative, then *timeout_exc* is raised after *timeout* second has passed.
    By default *timeout_exc* is ``socket.timeout('timed out')``.

    If :func:`cancel_wait` is called, raise ``socket.error(EBADF, 'File descriptor was closed in another greenlet')``.
    """
    io = get_hub().loop.io(fileno, 1)
    return wait(io, timeout, timeout_exc)


def wait_write(fileno, timeout=None, timeout_exc=timeout('timed out'), event=None):
    """Block the current greenlet until *fileno* is ready to write.

    If *timeout* is non-negative, then *timeout_exc* is raised after *timeout* second has passed.
    By default *timeout_exc* is ``socket.timeout('timed out')``.

    If :func:`cancel_wait` is called, raise ``socket.error(EBADF, 'File descriptor was closed in another greenlet')``.
    """
    io = get_hub().loop.io(fileno, 2)
    return wait(io, timeout, timeout_exc)


def wait_readwrite(fileno, timeout=None, timeout_exc=timeout('timed out'), event=None):
    """Block the current greenlet until *fileno* is ready to read or write.

    If *timeout* is non-negative, then *timeout_exc* is raised after *timeout* second has passed.
    By default *timeout_exc* is ``socket.timeout('timed out')``.

    If :func:`cancel_wait` is called, raise ``socket.error(EBADF, 'File descriptor was closed in another greenlet')``.
    """
    io = get_hub().loop.io(fileno, 3)
    return wait(io, timeout, timeout_exc)


cancel_wait_ex = error(EBADF, 'File descriptor was closed in another greenlet')


def cancel_wait(watcher):
    get_hub().cancel_wait(watcher, cancel_wait_ex)


if sys.version_info[:2] < (2, 7):
    _get_memory = buffer
elif sys.version_info[:2] < (3, 0):
    def _get_memory(string, offset):
        try:
            return memoryview(string)[offset:]
        except TypeError:
            return buffer(string, offset)
else:
    def _get_memory(string, offset):
        return memoryview(string)[offset:]


class _closedsocket(object):
    __slots__ = []

    def _dummy(*args, **kwargs):
        raise error(EBADF, 'Bad file descriptor')
    # All _delegate_methods must also be initialized here.
    send = recv = recv_into = sendto = recvfrom = recvfrom_into = _dummy
    __getattr__ = _dummy


timeout_default = object()


class socket(object):

    def __init__(self, family=AF_INET, type=SOCK_STREAM, proto=0, _sock=None):
        if _sock is None:
            self._sock = _realsocket(family, type, proto)
            self.timeout = _socket.getdefaulttimeout()
        else:
            if hasattr(_sock, '_sock'):
                self._sock = _sock._sock
                self.timeout = getattr(_sock, 'timeout', False)
                if self.timeout is False:
                    self.timeout = _socket.getdefaulttimeout()
            else:
                self._sock = _sock
                self.timeout = _socket.getdefaulttimeout()
        self._sock.setblocking(0)
        fileno = self._sock.fileno()
        self.hub = get_hub()
        io = self.hub.loop.io
        self._read_event = io(fileno, 1)
        self._write_event = io(fileno, 2)

    def __repr__(self):
        return '<%s at %s %s>' % (type(self).__name__, hex(id(self)), self._formatinfo())

    def __str__(self):
        return '<%s %s>' % (type(self).__name__, self._formatinfo())

    def _formatinfo(self):
        try:
            fileno = self.fileno()
        except Exception:
            fileno = str(sys.exc_info()[1])
        try:
            sockname = self.getsockname()
            sockname = '%s:%s' % sockname
        except Exception:
            sockname = None
        try:
            peername = self.getpeername()
            peername = '%s:%s' % peername
        except Exception:
            peername = None
        result = 'fileno=%s' % fileno
        if sockname is not None:
            result += ' sock=' + str(sockname)
        if peername is not None:
            result += ' peer=' + str(peername)
        if getattr(self, 'timeout', None) is not None:
            result += ' timeout=' + str(self.timeout)
        return result

    def _get_ref(self):
        return self._read_event.ref or self._write_event.ref

    def _set_ref(self, value):
        self._read_event.ref = value
        self._write_event.ref = value

    ref = property(_get_ref, _set_ref)

    def _wait(self, watcher, timeout_exc=timeout('timed out')):
        """Block the current greenlet until *watcher* has pending events.

        If *timeout* is non-negative, then *timeout_exc* is raised after *timeout* second has passed.
        By default *timeout_exc* is ``socket.timeout('timed out')``.

        If :func:`cancel_wait` is called, raise ``socket.error(EBADF, 'File descriptor was closed in another greenlet')``.
        """
        assert watcher.callback is None, 'This socket is already used by another greenlet: %r' % (watcher.callback, )
        if self.timeout is not None:
            timeout = Timeout.start_new(self.timeout, timeout_exc, ref=False)
        else:
            timeout = None
        try:
            self.hub.wait(watcher)
        finally:
            if timeout is not None:
                timeout.cancel()

    def accept(self):
        sock = self._sock
        while True:
            try:
                client_socket, address = sock.accept()
                break
            except error:
                ex = sys.exc_info()[1]
                if ex[0] != EWOULDBLOCK or self.timeout == 0.0:
                    raise
                sys.exc_clear()
            self._wait(self._read_event)
        return socket(_sock=client_socket), address

    def close(self, _closedsocket=_closedsocket, cancel_wait_ex=cancel_wait_ex):
        # This function should not reference any globals. See Python issue #808164.
        self.hub.cancel_wait(self._read_event, cancel_wait_ex)
        self.hub.cancel_wait(self._write_event, cancel_wait_ex)
        self._sock = _closedsocket()

    @property
    def closed(self):
        return isinstance(self._sock, _closedsocket)

    def connect(self, address):
        if self.timeout == 0.0:
            return self._sock.connect(address)
        sock = self._sock
        if isinstance(address, tuple):
            r = getaddrinfo(address[0], address[1], sock.family, sock.type, sock.proto)
            address = r[0][-1]
        if self.timeout is not None:
            timer = Timeout.start_new(self.timeout, timeout('timed out'))
        else:
            timer = None
        try:
            while True:
                err = sock.getsockopt(SOL_SOCKET, SO_ERROR)
                if err:
                    raise error(err, strerror(err))
                result = sock.connect_ex(address)
                if not result or result == EISCONN:
                    break
                elif (result in (EWOULDBLOCK, EINPROGRESS, EALREADY)) or (result == EINVAL and is_windows):
                    self._wait(self._write_event)
                else:
                    raise error(result, strerror(result))
        finally:
            if timer is not None:
                timer.cancel()

    def connect_ex(self, address):
        try:
            return self.connect(address) or 0
        except timeout:
            return EAGAIN
        except error:
            ex = sys.exc_info()[1]
            if type(ex) is error:
                return ex.args[0]
            else:
                raise  # gaierror is not silented by connect_ex

    def dup(self):
        """dup() -> socket object

        Return a new socket object connected to the same system resource.
        Note, that the new socket does not inherit the timeout."""
        return socket(_sock=self._sock)

    def makefile(self, mode='r', bufsize=-1):
        # Two things to look out for:
        # 1) Closing the original socket object should not close the
        #    socket (hence creating a new instance)
        # 2) The resulting fileobject must keep the timeout in order
        #    to be compatible with the stdlib's socket.makefile.
        return _fileobject(type(self)(_sock=self), mode, bufsize)

    def recv(self, *args):
        sock = self._sock  # keeping the reference so that fd is not closed during waiting
        while True:
            try:
                return sock.recv(*args)
            except error:
                ex = sys.exc_info()[1]
                if ex.args[0] != EWOULDBLOCK or self.timeout == 0.0:
                    raise
                # QQQ without clearing exc_info test__refcount.test_clean_exit fails
                sys.exc_clear()
            self._wait(self._read_event)

    def recvfrom(self, *args):
        sock = self._sock
        while True:
            try:
                return sock.recvfrom(*args)
            except error:
                ex = sys.exc_info()[1]
                if ex.args[0] != EWOULDBLOCK or self.timeout == 0.0:
                    raise
                sys.exc_clear()
            self._wait(self._read_event)

    def recvfrom_into(self, *args):
        sock = self._sock
        while True:
            try:
                return sock.recvfrom_into(*args)
            except error:
                ex = sys.exc_info()[1]
                if ex.args[0] != EWOULDBLOCK or self.timeout == 0.0:
                    raise
                sys.exc_clear()
            self._wait(self._read_event)

    def recv_into(self, *args):
        sock = self._sock
        while True:
            try:
                return sock.recv_into(*args)
            except error:
                ex = sys.exc_info()[1]
                if ex.args[0] != EWOULDBLOCK or self.timeout == 0.0:
                    raise
                sys.exc_clear()
            self._wait(self._read_event)

    def send(self, data, flags=0, timeout=timeout_default):
        sock = self._sock
        if timeout is timeout_default:
            timeout = self.timeout
        try:
            return sock.send(data, flags)
        except error:
            ex = sys.exc_info()[1]
            if ex.args[0] != EWOULDBLOCK or timeout == 0.0:
                raise
            sys.exc_clear()
            self._wait(self._write_event)
            try:
                return sock.send(data, flags)
            except error:
                ex2 = sys.exc_info()[1]
                if ex2.args[0] == EWOULDBLOCK:
                    return 0
                raise

    def sendall(self, data, flags=0):
        if isinstance(data, unicode):
            data = data.encode()
        # this sendall is also reused by gevent.ssl.SSLSocket subclass,
        # so it should not call self._sock methods directly
        if self.timeout is None:
            data_sent = 0
            while data_sent < len(data):
                data_sent += self.send(_get_memory(data, data_sent), flags)
        else:
            timeleft = self.timeout
            end = time.time() + timeleft
            data_sent = 0
            while True:
                data_sent += self.send(_get_memory(data, data_sent), flags, timeout=timeleft)
                if data_sent >= len(data):
                    break
                timeleft = end - time.time()
                if timeleft <= 0:
                    raise timeout('timed out')

    def sendto(self, *args):
        sock = self._sock
        try:
            return sock.sendto(*args)
        except error:
            ex = sys.exc_info()[1]
            if ex.args[0] != EWOULDBLOCK or timeout == 0.0:
                raise
            sys.exc_clear()
            self._wait(self._write_event)
            try:
                return sock.sendto(*args)
            except error:
                ex2 = sys.exc_info()[1]
                if ex2.args[0] == EWOULDBLOCK:
                    return 0
                raise

    def setblocking(self, flag):
        if flag:
            self.timeout = None
        else:
            self.timeout = 0.0

    def settimeout(self, howlong):
        if howlong is not None:
            try:
                f = howlong.__float__
            except AttributeError:
                raise TypeError('a float is required')
            howlong = f()
            if howlong < 0.0:
                raise ValueError('Timeout value out of range')
        self.timeout = howlong

    def gettimeout(self):
        return self.timeout

    def shutdown(self, how):
        if how == 0:  # SHUT_RD
            self.hub.cancel_wait(self._read_event, cancel_wait_ex)
        elif how == 1:  # SHUT_WR
            self.hub.cancel_wait(self._write_event, cancel_wait_ex)
        else:
            self.hub.cancel_wait(self._read_event, cancel_wait_ex)
            self.hub.cancel_wait(self._write_event, cancel_wait_ex)
        self._sock.shutdown(how)

    family = property(lambda self: self._sock.family, doc="the socket family")
    type = property(lambda self: self._sock.type, doc="the socket type")
    proto = property(lambda self: self._sock.proto, doc="the socket protocol")

    # delegate the functions that we haven't implemented to the real socket object

    _s = ("def %s(self, *args): return self._sock.%s(*args)\n\n"
          "%s.__doc__ = _realsocket.%s.__doc__\n")
    for _m in set(__socket__._socketmethods) - set(locals()):
        exec (_s % (_m, _m, _m, _m))
    del _m, _s

SocketType = socket

if hasattr(_socket, 'socketpair'):

    def socketpair(*args):
        one, two = _socket.socketpair(*args)
        return socket(_sock=one), socket(_sock=two)
else:
    __implements__.remove('socketpair')

if hasattr(_socket, 'fromfd'):

    def fromfd(*args):
        return socket(_sock=_socket.fromfd(*args))
else:
    __implements__.remove('fromfd')


try:
    _GLOBAL_DEFAULT_TIMEOUT = __socket__._GLOBAL_DEFAULT_TIMEOUT
except AttributeError:
    _GLOBAL_DEFAULT_TIMEOUT = object()


def create_connection(address, timeout=_GLOBAL_DEFAULT_TIMEOUT, source_address=None):
    """Connect to *address* and return the socket object.

    Convenience function.  Connect to *address* (a 2-tuple ``(host,
    port)``) and return the socket object.  Passing the optional
    *timeout* parameter will set the timeout on the socket instance
    before attempting to connect.  If no *timeout* is supplied, the
    global default timeout setting returned by :func:`getdefaulttimeout`
    is used. If *source_address* is set it must be a tuple of (host, port)
    for the socket to bind as a source address before making the connection.
    An host of '' or port 0 tells the OS to use the default.
    """

    host, port = address
    err = None
    for res in getaddrinfo(host, port, 0 if has_ipv6 else AF_INET, SOCK_STREAM):
        af, socktype, proto, _canonname, sa = res
        sock = None
        try:
            sock = socket(af, socktype, proto)
            if timeout is not _GLOBAL_DEFAULT_TIMEOUT:
                sock.settimeout(timeout)
            if source_address:
                sock.bind(source_address)
            sock.connect(sa)
            return sock
        except error:
            err = sys.exc_info()[1]
            # without exc_clear(), if connect() fails once, the socket is referenced by the frame in exc_info
            # and the next bind() fails (see test__socket.TestCreateConnection)
            # that does not happen with regular sockets though, because _socket.socket.connect() is a built-in.
            # this is similar to "getnameinfo loses a reference" failure in test_socket.py
            sys.exc_clear()
            if sock is not None:
                sock.close()
    if err is not None:
        raise err
    else:
        raise error("getaddrinfo returns an empty list")


class BlockingResolver(object):

    def __init__(self, hub=None):
        pass

    def close(self):
        pass

    for method in ['gethostbyname',
                   'gethostbyname_ex',
                   'getaddrinfo',
                   'gethostbyaddr',
                   'getnameinfo']:
        locals()[method] = staticmethod(getattr(_socket, method))


def gethostbyname(hostname):
    return get_hub().resolver.gethostbyname(hostname)


def gethostbyname_ex(hostname):
    return get_hub().resolver.gethostbyname_ex(hostname)


def getaddrinfo(host, port, family=0, socktype=0, proto=0, flags=0):
    return get_hub().resolver.getaddrinfo(host, port, family, socktype, proto, flags)


def gethostbyaddr(ip_address):
    return get_hub().resolver.gethostbyaddr(ip_address)


def getnameinfo(sockaddr, flags):
    return get_hub().resolver.getnameinfo(sockaddr, flags)


def getfqdn(name=''):
    """Get fully qualified domain name from name.

    An empty argument is interpreted as meaning the local host.

    First the hostname returned by gethostbyaddr() is checked, then
    possibly existing aliases. In case no FQDN is available, hostname
    from gethostname() is returned.
    """
    name = name.strip()
    if not name or name == '0.0.0.0':
        name = gethostname()
    try:
        hostname, aliases, ipaddrs = gethostbyaddr(name)
    except error:
        pass
    else:
        aliases.insert(0, hostname)
        for name in aliases:
            if '.' in name:
                break
        else:
            name = hostname
    return name


try:
    from gevent.ssl import sslwrap_simple as ssl, SSLError as sslerror, SSLSocket as SSLType
    _have_ssl = True
except ImportError:
    _have_ssl = False


if sys.version_info[:2] <= (2, 5) and _have_ssl:
    __implements__.extend(['ssl', 'sslerror', 'SSLType'])


__all__ = __implements__ + __extensions__ + __imports__