/usr/lib/python2.7/dist-packages/gevent/resolver_ares.py is in python-gevent 1.1.0-2.
This file is owned by root:root, with mode 0o644.
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"""
c-ares based hostname resolver.
"""
from __future__ import absolute_import
import os
import sys
from _socket import getservbyname, getaddrinfo, gaierror, error
from gevent.hub import Waiter, get_hub, string_types, text_type, integer_types, reraise, PY3
from gevent.socket import AF_UNSPEC, AF_INET, AF_INET6, SOCK_STREAM, SOCK_DGRAM, SOCK_RAW, AI_NUMERICHOST, EAI_SERVICE, AI_PASSIVE
from gevent.ares import channel, InvalidIP
__all__ = ['Resolver']
class Resolver(object):
"""
Implementation of the resolver API using the `c-ares`_ library.
This implementation uses the c-ares library to handle name
resolution. c-ares is natively asynchronous at the socket level
and so integrates well into gevent's event loop.
In comparison to :class:`gevent.resolver_thread.Resolver`, the
implementation is much more complex. In addition, there have been
reports of it not properly honoring certain system configurations.
However, because it does not use threads, it may scale better.
.. caution:: This module is considered extremely experimental on PyPy, and
due to its implementation in cython, it may be slower. It may also lead to
interpreter crashes.
.. _c-ares: http://c-ares.haxx.se
"""
ares_class = channel
def __init__(self, hub=None, use_environ=True, **kwargs):
if hub is None:
hub = get_hub()
self.hub = hub
if use_environ:
for key in os.environ:
if key.startswith('GEVENTARES_'):
name = key[11:].lower()
if name:
value = os.environ[key]
kwargs.setdefault(name, value)
self.ares = self.ares_class(hub.loop, **kwargs)
self.pid = os.getpid()
self.params = kwargs
self.fork_watcher = hub.loop.fork(ref=False)
self.fork_watcher.start(self._on_fork)
def __repr__(self):
return '<gevent.resolver_ares.Resolver at 0x%x ares=%r>' % (id(self), self.ares)
def _on_fork(self):
# NOTE: See comment in gevent.hub.reinit.
pid = os.getpid()
if pid != self.pid:
self.hub.loop.run_callback(self.ares.destroy)
self.ares = self.ares_class(self.hub.loop, **self.params)
self.pid = pid
def close(self):
if self.ares is not None:
self.hub.loop.run_callback(self.ares.destroy)
self.ares = None
self.fork_watcher.stop()
def gethostbyname(self, hostname, family=AF_INET):
hostname = _resolve_special(hostname, family)
return self.gethostbyname_ex(hostname, family)[-1][0]
def gethostbyname_ex(self, hostname, family=AF_INET):
if PY3:
if isinstance(hostname, str):
hostname = hostname.encode('idna')
elif not isinstance(hostname, (bytes, bytearray)):
raise TypeError('Expected es(idna), not %s' % type(hostname).__name__)
else:
if isinstance(hostname, text_type):
hostname = hostname.encode('ascii')
elif not isinstance(hostname, str):
raise TypeError('Expected string, not %s' % type(hostname).__name__)
while True:
ares = self.ares
try:
waiter = Waiter(self.hub)
ares.gethostbyname(waiter, hostname, family)
result = waiter.get()
if not result[-1]:
raise gaierror(-5, 'No address associated with hostname')
return result
except gaierror:
if ares is self.ares:
raise
# "self.ares is not ares" means channel was destroyed (because we were forked)
def _lookup_port(self, port, socktype):
socktypes = []
if isinstance(port, string_types):
try:
port = int(port)
except ValueError:
try:
if socktype == 0:
origport = port
try:
port = getservbyname(port, 'tcp')
socktypes.append(SOCK_STREAM)
except error:
port = getservbyname(port, 'udp')
socktypes.append(SOCK_DGRAM)
else:
try:
if port == getservbyname(origport, 'udp'):
socktypes.append(SOCK_DGRAM)
except error:
pass
elif socktype == SOCK_STREAM:
port = getservbyname(port, 'tcp')
elif socktype == SOCK_DGRAM:
port = getservbyname(port, 'udp')
else:
raise gaierror(EAI_SERVICE, 'Servname not supported for ai_socktype')
except error as ex:
if 'not found' in str(ex):
raise gaierror(EAI_SERVICE, 'Servname not supported for ai_socktype')
else:
raise gaierror(str(ex))
except UnicodeEncodeError:
raise error('Int or String expected')
elif port is None:
port = 0
elif isinstance(port, integer_types):
pass
else:
raise error('Int or String expected', port, type(port))
port = int(port % 65536)
if not socktypes and socktype:
socktypes.append(socktype)
return port, socktypes
def _getaddrinfo(self, host, port, family=0, socktype=0, proto=0, flags=0):
if isinstance(host, text_type):
host = host.encode('idna')
elif not isinstance(host, str) or (flags & AI_NUMERICHOST):
# this handles cases which do not require network access
# 1) host is None
# 2) host is of an invalid type
# 3) AI_NUMERICHOST flag is set
return getaddrinfo(host, port, family, socktype, proto, flags)
# we also call _socket.getaddrinfo below if family is not one of AF_*
port, socktypes = self._lookup_port(port, socktype)
socktype_proto = [(SOCK_STREAM, 6), (SOCK_DGRAM, 17), (SOCK_RAW, 0)]
if socktypes:
socktype_proto = [(x, y) for (x, y) in socktype_proto if x in socktypes]
if proto:
socktype_proto = [(x, y) for (x, y) in socktype_proto if proto == y]
ares = self.ares
if family == AF_UNSPEC:
values = Values(self.hub, 2)
ares.gethostbyname(values, host, AF_INET)
ares.gethostbyname(values, host, AF_INET6)
elif family == AF_INET:
values = Values(self.hub, 1)
ares.gethostbyname(values, host, AF_INET)
elif family == AF_INET6:
values = Values(self.hub, 1)
ares.gethostbyname(values, host, AF_INET6)
else:
raise gaierror(5, 'ai_family not supported: %r' % (family, ))
values = values.get()
if len(values) == 2 and values[0] == values[1]:
values.pop()
result = []
result4 = []
result6 = []
for addrs in values:
if addrs.family == AF_INET:
for addr in addrs[-1]:
sockaddr = (addr, port)
for socktype, proto in socktype_proto:
result4.append((AF_INET, socktype, proto, '', sockaddr))
elif addrs.family == AF_INET6:
for addr in addrs[-1]:
if addr == '::1':
dest = result
else:
dest = result6
sockaddr = (addr, port, 0, 0)
for socktype, proto in socktype_proto:
dest.append((AF_INET6, socktype, proto, '', sockaddr))
result += result4 + result6
if not result:
raise gaierror(-5, 'No address associated with hostname')
return result
def getaddrinfo(self, host, port, family=0, socktype=0, proto=0, flags=0):
while True:
ares = self.ares
try:
return self._getaddrinfo(host, port, family, socktype, proto, flags)
except gaierror:
if ares is self.ares:
raise
def _gethostbyaddr(self, ip_address):
if PY3:
if isinstance(ip_address, str):
ip_address = ip_address.encode('idna')
elif not isinstance(ip_address, (bytes, bytearray)):
raise TypeError('Expected es(idna), not %s' % type(ip_address).__name__)
else:
if isinstance(ip_address, text_type):
ip_address = ip_address.encode('ascii')
elif not isinstance(ip_address, str):
raise TypeError('Expected string, not %s' % type(ip_address).__name__)
waiter = Waiter(self.hub)
try:
self.ares.gethostbyaddr(waiter, ip_address)
return waiter.get()
except InvalidIP:
result = self._getaddrinfo(ip_address, None, family=AF_UNSPEC, socktype=SOCK_DGRAM)
if not result:
raise
_ip_address = result[0][-1][0]
if isinstance(_ip_address, text_type):
_ip_address = _ip_address.encode('ascii')
if _ip_address == ip_address:
raise
waiter.clear()
self.ares.gethostbyaddr(waiter, _ip_address)
return waiter.get()
def gethostbyaddr(self, ip_address):
ip_address = _resolve_special(ip_address, AF_UNSPEC)
while True:
ares = self.ares
try:
return self._gethostbyaddr(ip_address)
except gaierror:
if ares is self.ares:
raise
def _getnameinfo(self, sockaddr, flags):
if not isinstance(flags, int):
raise TypeError('an integer is required')
if not isinstance(sockaddr, tuple):
raise TypeError('getnameinfo() argument 1 must be a tuple')
address = sockaddr[0]
if not PY3 and isinstance(address, text_type):
address = address.encode('ascii')
if not isinstance(address, string_types):
raise TypeError('sockaddr[0] must be a string, not %s' % type(address).__name__)
port = sockaddr[1]
if not isinstance(port, int):
raise TypeError('port must be an integer, not %s' % type(port))
waiter = Waiter(self.hub)
result = self._getaddrinfo(address, str(sockaddr[1]), family=AF_UNSPEC, socktype=SOCK_DGRAM)
if not result:
reraise(*sys.exc_info())
elif len(result) != 1:
raise error('sockaddr resolved to multiple addresses')
family, socktype, proto, name, address = result[0]
if family == AF_INET:
if len(sockaddr) != 2:
raise error("IPv4 sockaddr must be 2 tuple")
elif family == AF_INET6:
address = address[:2] + sockaddr[2:]
self.ares.getnameinfo(waiter, address, flags)
node, service = waiter.get()
if service is None:
service = '0'
return node, service
def getnameinfo(self, sockaddr, flags):
while True:
ares = self.ares
try:
return self._getnameinfo(sockaddr, flags)
except gaierror:
if ares is self.ares:
raise
class Values(object):
# helper to collect multiple values; ignore errors unless nothing has succeeded
# QQQ could probably be moved somewhere - hub.py?
__slots__ = ['count', 'values', 'error', 'waiter']
def __init__(self, hub, count):
self.count = count
self.values = []
self.error = None
self.waiter = Waiter(hub)
def __call__(self, source):
self.count -= 1
if source.exception is None:
self.values.append(source.value)
else:
self.error = source.exception
if self.count <= 0:
self.waiter.switch()
def get(self):
self.waiter.get()
if self.values:
return self.values
else:
raise self.error
def _resolve_special(hostname, family):
if hostname == '':
result = getaddrinfo(None, 0, family, SOCK_DGRAM, 0, AI_PASSIVE)
if len(result) != 1:
raise error('wildcard resolved to multiple address')
return result[0][4][0]
return hostname
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