97 lines
2.9 KiB
Python
97 lines
2.9 KiB
Python
|
# Copyright (C) 2016 Christian Heimes
|
||
|
|
"""socketfromfd -- socket.fromd() with auto-discovery
|
||
|
|
|
||
|
|
ATTENTION: Do not remove this backport till the minimum required version is
|
||
|
|
Python 3.7. See https://bugs.python.org/issue28134 for details.
|
||
|
|
"""
|
||
|
|
from __future__ import print_function
|
||
|
|
|
||
|
|
import ctypes
|
||
|
|
import os
|
||
|
|
import socket
|
||
|
|
import sys
|
||
|
|
from ctypes.util import find_library
|
||
|
|
|
||
|
|
__all__ = ('fromfd',)
|
||
|
|
|
||
|
|
SO_DOMAIN = getattr(socket, 'SO_DOMAIN', 39)
|
||
|
|
SO_TYPE = getattr(socket, 'SO_TYPE', 3)
|
||
|
|
SO_PROTOCOL = getattr(socket, 'SO_PROTOCOL', 38)
|
||
|
|
|
||
|
|
|
||
|
|
_libc_name = find_library('c')
|
||
|
|
if _libc_name is not None:
|
||
|
|
libc = ctypes.CDLL(_libc_name, use_errno=True)
|
||
|
|
else:
|
||
|
|
raise OSError('libc not found')
|
||
|
|
|
||
|
|
|
||
|
|
def _errcheck_errno(result, func, arguments):
|
||
|
|
"""Raise OSError by errno for -1
|
||
|
|
"""
|
||
|
|
if result == -1:
|
||
|
|
errno = ctypes.get_errno()
|
||
|
|
raise OSError(errno, os.strerror(errno))
|
||
|
|
return arguments
|
||
|
|
|
||
|
|
|
||
|
|
_libc_getsockopt = libc.getsockopt
|
||
|
|
_libc_getsockopt.argtypes = [
|
||
|
|
ctypes.c_int, # int sockfd
|
||
|
|
ctypes.c_int, # int level
|
||
|
|
ctypes.c_int, # int optname
|
||
|
|
ctypes.c_void_p, # void *optval
|
||
|
|
ctypes.POINTER(ctypes.c_uint32) # socklen_t *optlen
|
||
|
|
]
|
||
|
|
_libc_getsockopt.restype = ctypes.c_int # 0: ok, -1: err
|
||
|
|
_libc_getsockopt.errcheck = _errcheck_errno
|
||
|
|
|
||
|
|
|
||
|
|
def _raw_getsockopt(fd, level, optname):
|
||
|
|
"""Make raw getsockopt() call for int32 optval
|
||
|
|
|
||
|
|
:param fd: socket fd
|
||
|
|
:param level: SOL_*
|
||
|
|
:param optname: SO_*
|
||
|
|
:return: value as int
|
||
|
|
"""
|
||
|
|
optval = ctypes.c_int(0)
|
||
|
|
optlen = ctypes.c_uint32(4)
|
||
|
|
_libc_getsockopt(fd, level, optname,
|
||
|
|
ctypes.byref(optval), ctypes.byref(optlen))
|
||
|
|
return optval.value
|
||
|
|
|
||
|
|
|
||
|
|
def fromfd(fd, keep_fd=True):
|
||
|
|
"""Create a socket from a file descriptor
|
||
|
|
|
||
|
|
socket domain (family), type and protocol are auto-detected. By default
|
||
|
|
the socket uses a dup()ed fd. The original fd can be closed.
|
||
|
|
|
||
|
|
The parameter `keep_fd` influences fd duplication. Under Python 2 the
|
||
|
|
fd is still duplicated but the input fd is closed. Under Python 3 and
|
||
|
|
with `keep_fd=True`, the new socket object uses the same fd.
|
||
|
|
|
||
|
|
:param fd: socket fd
|
||
|
|
:type fd: int
|
||
|
|
:param keep_fd: keep input fd
|
||
|
|
:type keep_fd: bool
|
||
|
|
:return: socket.socket instance
|
||
|
|
:raises OSError: for invalid socket fd
|
||
|
|
"""
|
||
|
|
family = _raw_getsockopt(fd, socket.SOL_SOCKET, SO_DOMAIN)
|
||
|
|
typ = _raw_getsockopt(fd, socket.SOL_SOCKET, SO_TYPE)
|
||
|
|
proto = _raw_getsockopt(fd, socket.SOL_SOCKET, SO_PROTOCOL)
|
||
|
|
if sys.version_info.major == 2:
|
||
|
|
# Python 2 has no fileno argument and always duplicates the fd
|
||
|
|
sockobj = socket.fromfd(fd, family, typ, proto)
|
||
|
|
sock = socket.socket(None, None, None, _sock=sockobj)
|
||
|
|
if not keep_fd:
|
||
|
|
os.close(fd)
|
||
|
|
return sock
|
||
|
|
else:
|
||
|
|
if keep_fd:
|
||
|
|
return socket.fromfd(fd, family, typ, proto)
|
||
|
|
else:
|
||
|
|
return socket.socket(family, typ, proto, fileno=fd)
|