cpython/Lib/socket.py

338 lines
10 KiB
Python

# Wrapper module for _socket, providing some additional facilities
# implemented in Python.
"""\
This module provides socket operations and some related functions.
On Unix, it supports IP (Internet Protocol) and Unix domain sockets.
On other systems, it only supports IP. Functions specific for a
socket are available as methods of the socket object.
Functions:
socket() -- create a new socket object
socketpair() -- create a pair of new socket objects [*]
fromfd() -- create a socket object from an open file descriptor [*]
gethostname() -- return the current hostname
gethostbyname() -- map a hostname to its IP number
gethostbyaddr() -- map an IP number or hostname to DNS info
getservbyname() -- map a service name and a protocol name to a port number
getprotobyname() -- mape a protocol name (e.g. 'tcp') to a number
ntohs(), ntohl() -- convert 16, 32 bit int from network to host byte order
htons(), htonl() -- convert 16, 32 bit int from host to network byte order
inet_aton() -- convert IP addr string (123.45.67.89) to 32-bit packed format
inet_ntoa() -- convert 32-bit packed format IP to string (123.45.67.89)
ssl() -- secure socket layer support (only available if configured)
socket.getdefaulttimeout() -- get the default timeout value
socket.setdefaulttimeout() -- set the default timeout value
create_connection() -- connects to an address, with an optional timeout
[*] not available on all platforms!
Special objects:
SocketType -- type object for socket objects
error -- exception raised for I/O errors
has_ipv6 -- boolean value indicating if IPv6 is supported
Integer constants:
AF_INET, AF_UNIX -- socket domains (first argument to socket() call)
SOCK_STREAM, SOCK_DGRAM, SOCK_RAW -- socket types (second argument)
Many other constants may be defined; these may be used in calls to
the setsockopt() and getsockopt() methods.
"""
import _socket
from _socket import *
_have_ssl = False
try:
import _ssl
from _ssl import *
_have_ssl = True
except ImportError:
pass
import os, sys, io
try:
from errno import EBADF
except ImportError:
EBADF = 9
__all__ = ["getfqdn"]
__all__.extend(os._get_exports_list(_socket))
if _have_ssl:
__all__.extend(os._get_exports_list(_ssl))
# WSA error codes
if sys.platform.lower().startswith("win"):
errorTab = {}
errorTab[10004] = "The operation was interrupted."
errorTab[10009] = "A bad file handle was passed."
errorTab[10013] = "Permission denied."
errorTab[10014] = "A fault occurred on the network??" # WSAEFAULT
errorTab[10022] = "An invalid operation was attempted."
errorTab[10035] = "The socket operation would block"
errorTab[10036] = "A blocking operation is already in progress."
errorTab[10048] = "The network address is in use."
errorTab[10054] = "The connection has been reset."
errorTab[10058] = "The network has been shut down."
errorTab[10060] = "The operation timed out."
errorTab[10061] = "Connection refused."
errorTab[10063] = "The name is too long."
errorTab[10064] = "The host is down."
errorTab[10065] = "The host is unreachable."
__all__.append("errorTab")
# True if os.dup() can duplicate socket descriptors.
# (On Windows at least, os.dup only works on files)
_can_dup_socket = hasattr(_socket.socket, "dup")
if _can_dup_socket:
def fromfd(fd, family=AF_INET, type=SOCK_STREAM, proto=0):
nfd = os.dup(fd)
return socket(family, type, proto, fileno=nfd)
class SocketCloser:
"""Helper to manage socket close() logic for makefile().
The OS socket should not be closed until the socket and all
of its makefile-children are closed. If the refcount is zero
when socket.close() is called, this is easy: Just close the
socket. If the refcount is non-zero when socket.close() is
called, then the real close should not occur until the last
makefile-child is closed.
"""
def __init__(self, sock):
self._sock = sock
self._makefile_refs = 0
# Test whether the socket is open.
try:
sock.fileno()
self._socket_open = True
except error:
self._socket_open = False
def socket_close(self):
self._socket_open = False
self.close()
def makefile_open(self):
self._makefile_refs += 1
def makefile_close(self):
self._makefile_refs -= 1
self.close()
def close(self):
if not (self._socket_open or self._makefile_refs):
self._sock._real_close()
class socket(_socket.socket):
"""A subclass of _socket.socket adding the makefile() method."""
__slots__ = ["__weakref__", "_closer"]
if not _can_dup_socket:
__slots__.append("_base")
def __init__(self, family=AF_INET, type=SOCK_STREAM, proto=0, fileno=None):
if fileno is None:
_socket.socket.__init__(self, family, type, proto)
else:
_socket.socket.__init__(self, family, type, proto, fileno)
# Defer creating a SocketCloser until makefile() is actually called.
self._closer = None
def __repr__(self):
"""Wrap __repr__() to reveal the real class name."""
s = _socket.socket.__repr__(self)
if s.startswith("<socket object"):
s = "<%s.%s%s" % (self.__class__.__module__,
self.__class__.__name__,
s[7:])
return s
def accept(self):
"""Wrap accept() to give the connection the right type."""
conn, addr = _socket.socket.accept(self)
fd = conn.fileno()
nfd = fd
if _can_dup_socket:
nfd = os.dup(fd)
wrapper = socket(self.family, self.type, self.proto, fileno=nfd)
if fd == nfd:
wrapper._base = conn # Keep the base alive
else:
conn.close()
return wrapper, addr
def makefile(self, mode="r", buffering=None, *,
encoding=None, newline=None):
"""Return an I/O stream connected to the socket.
The arguments are as for io.open() after the filename,
except the only mode characters supported are 'r', 'w' and 'b'.
The semantics are similar too. (XXX refactor to share code?)
"""
for c in mode:
if c not in {"r", "w", "b"}:
raise ValueError("invalid mode %r (only r, w, b allowed)")
writing = "w" in mode
reading = "r" in mode or not writing
assert reading or writing
binary = "b" in mode
rawmode = ""
if reading:
rawmode += "r"
if writing:
rawmode += "w"
if self._closer is None:
self._closer = SocketCloser(self)
raw = SocketIO(self, rawmode, self._closer)
if buffering is None:
buffering = -1
if buffering < 0:
buffering = io.DEFAULT_BUFFER_SIZE
if buffering == 0:
if not binary:
raise ValueError("unbuffered streams must be binary")
raw.name = self.fileno()
raw.mode = mode
return raw
if reading and writing:
buffer = io.BufferedRWPair(raw, raw, buffering)
elif reading:
buffer = io.BufferedReader(raw, buffering)
else:
assert writing
buffer = io.BufferedWriter(raw, buffering)
if binary:
buffer.name = self.fileno()
buffer.mode = mode
return buffer
text = io.TextIOWrapper(buffer, encoding, newline)
text.name = self.fileno()
text.mode = mode
return text
def close(self):
if self._closer is None:
self._real_close()
else:
self._closer.socket_close()
# _real_close calls close on the _socket.socket base class.
if not _can_dup_socket:
def _real_close(self):
_socket.socket.close(self)
base = getattr(self, "_base", None)
if base is not None:
self._base = None
base.close()
else:
def _real_close(self):
_socket.socket.close(self)
class SocketIO(io.RawIOBase):
"""Raw I/O implementation for stream sockets.
This class supports the makefile() method on sockets. It provides
the raw I/O interface on top of a socket object.
"""
# XXX More docs
def __init__(self, sock, mode, closer):
assert mode in ("r", "w", "rw")
io.RawIOBase.__init__(self)
self._sock = sock
self._mode = mode
self._closer = closer
closer.makefile_open()
def readinto(self, b):
return self._sock.recv_into(b)
def write(self, b):
return self._sock.send(b)
def readable(self):
return "r" in self._mode
def writable(self):
return "w" in self._mode
def fileno(self):
return self._sock.fileno()
def close(self):
if self.closed:
return
self._closer.makefile_close()
io.RawIOBase.close(self)
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
def create_connection(address, timeout=None):
"""Connect to address (host, port) with an optional timeout.
Provides access to socketobject timeout for higher-level
protocols. Passing a timeout will set the timeout on the
socket instance (if not present, or passed as None, the
default global timeout setting will be used).
"""
msg = "getaddrinfo returns an empty list"
host, port = address
for res in getaddrinfo(host, port, 0, SOCK_STREAM):
af, socktype, proto, canonname, sa = res
sock = None
try:
sock = socket(af, socktype, proto)
if timeout is not None:
sock.settimeout(timeout)
sock.connect(sa)
return sock
except error as err:
msg = err
if sock is not None:
sock.close()
raise error(msg)