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# Copyright (c) 2010, 2012, 2014, 2015 Nicira, Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at:
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import errno
import os
import os.path
import random
import socket
import sys
import six
from six.moves import range
import ovs.fatal_signal
import ovs.poller
import ovs.vlog
if sys.platform == 'win32':
import ovs.winutils as winutils
import win32file
vlog = ovs.vlog.Vlog("socket_util")
def make_short_name(long_name):
if long_name is None:
return None
long_name = os.path.abspath(long_name)
long_dirname = os.path.dirname(long_name)
tmpdir = os.getenv('TMPDIR', '/tmp')
for x in range(0, 1000):
link_name = \
'%s/ovs-un-py-%d-%d' % (tmpdir, random.randint(0, 10000), x)
try:
os.symlink(long_dirname, link_name)
ovs.fatal_signal.add_file_to_unlink(link_name)
return os.path.join(link_name, os.path.basename(long_name))
except OSError as e:
if e.errno != errno.EEXIST:
break
raise Exception("Failed to create temporary symlink")
def free_short_name(short_name):
if short_name is None:
return
link_name = os.path.dirname(short_name)
ovs.fatal_signal.unlink_file_now(link_name)
def make_unix_socket(style, nonblock, bind_path, connect_path, short=False):
"""Creates a Unix domain socket in the given 'style' (either
socket.SOCK_DGRAM or socket.SOCK_STREAM) that is bound to 'bind_path' (if
'bind_path' is not None) and connected to 'connect_path' (if 'connect_path'
is not None). If 'nonblock' is true, the socket is made non-blocking.
Returns (error, socket): on success 'error' is 0 and 'socket' is a new
socket object, on failure 'error' is a positive errno value and 'socket' is
None."""
try:
sock = socket.socket(socket.AF_UNIX, style)
except socket.error as e:
return get_exception_errno(e), None
try:
if nonblock:
set_nonblocking(sock)
if bind_path is not None:
# Delete bind_path but ignore ENOENT.
try:
os.unlink(bind_path)
except OSError as e:
if e.errno != errno.ENOENT:
return e.errno, None
ovs.fatal_signal.add_file_to_unlink(bind_path)
sock.bind(bind_path)
try:
os.fchmod(sock.fileno(), 0o700)
except OSError as e:
pass
if connect_path is not None:
try:
sock.connect(connect_path)
except socket.error as e:
if get_exception_errno(e) != errno.EINPROGRESS:
raise
return 0, sock
except socket.error as e:
sock.close()
if (bind_path is not None and
os.path.exists(bind_path)):
ovs.fatal_signal.unlink_file_now(bind_path)
eno = ovs.socket_util.get_exception_errno(e)
if (eno == "AF_UNIX path too long" and
os.uname()[0] == "Linux"):
short_connect_path = None
short_bind_path = None
connect_dirfd = None
bind_dirfd = None
# Try workaround using /proc/self/fd
if connect_path is not None:
dirname = os.path.dirname(connect_path)
basename = os.path.basename(connect_path)
try:
connect_dirfd = os.open(dirname,
os.O_DIRECTORY | os.O_RDONLY)
except OSError as err:
return get_exception_errno(err), None
short_connect_path = "/proc/self/fd/%d/%s" % (connect_dirfd,
basename)
if bind_path is not None:
dirname = os.path.dirname(bind_path)
basename = os.path.basename(bind_path)
try:
bind_dirfd = os.open(dirname, os.O_DIRECTORY | os.O_RDONLY)
except OSError as err:
return get_exception_errno(err), None
short_bind_path = "/proc/self/fd/%d/%s" % (bind_dirfd,
basename)
try:
return make_unix_socket(style, nonblock, short_bind_path,
short_connect_path)
finally:
if connect_dirfd is not None:
os.close(connect_dirfd)
if bind_dirfd is not None:
os.close(bind_dirfd)
elif (eno == "AF_UNIX path too long"):
if short:
return get_exception_errno(e), None
short_bind_path = None
try:
short_bind_path = make_short_name(bind_path)
short_connect_path = make_short_name(connect_path)
except:
free_short_name(short_bind_path)
return errno.ENAMETOOLONG, None
try:
return make_unix_socket(style, nonblock, short_bind_path,
short_connect_path, short=True)
finally:
free_short_name(short_bind_path)
free_short_name(short_connect_path)
else:
return get_exception_errno(e), None
def check_connection_completion(sock):
p = ovs.poller.SelectPoll()
if sys.platform == "win32":
event = winutils.get_new_event(None, False, True, None)
# Receive notification of readiness for writing, of completed
# connection or multipoint join operation, and of socket closure.
win32file.WSAEventSelect(sock, event,
win32file.FD_WRITE |
win32file.FD_CONNECT |
win32file.FD_CLOSE)
p.register(event, ovs.poller.POLLOUT)
else:
p.register(sock, ovs.poller.POLLOUT)
pfds = p.poll(0)
if len(pfds) == 1:
revents = pfds[0][1]
if revents & ovs.poller.POLLERR:
try:
# The following should raise an exception.
socket.send("\0", socket.MSG_DONTWAIT)
# (Here's where we end up if it didn't.)
# XXX rate-limit
vlog.err("poll return POLLERR but send succeeded")
return errno.EPROTO
except socket.error as e:
return get_exception_errno(e)
else:
return 0
else:
return errno.EAGAIN
def is_valid_ipv4_address(address):
try:
socket.inet_pton(socket.AF_INET, address)
except AttributeError:
try:
socket.inet_aton(address)
except socket.error:
return False
except socket.error:
return False
return True
def inet_parse_active(target, default_port):
address = target.split(":")
if len(address) >= 2:
host_name = ":".join(address[0:-1]).lstrip('[').rstrip(']')
port = int(address[-1])
else:
if default_port:
port = default_port
else:
raise ValueError("%s: port number must be specified" % target)
host_name = address[0]
if not host_name:
raise ValueError("%s: bad peer name format" % target)
return (host_name, port)
def inet_open_active(style, target, default_port, dscp):
address = inet_parse_active(target, default_port)
try:
is_addr_inet = is_valid_ipv4_address(address[0])
if is_addr_inet:
sock = socket.socket(socket.AF_INET, style, 0)
family = socket.AF_INET
else:
sock = socket.socket(socket.AF_INET6, style, 0)
family = socket.AF_INET6
except socket.error as e:
return get_exception_errno(e), None
try:
set_nonblocking(sock)
set_dscp(sock, family, dscp)
try:
sock.connect(address)
except socket.error as e:
error = get_exception_errno(e)
if sys.platform == 'win32' and error == errno.WSAEWOULDBLOCK:
# WSAEWOULDBLOCK would be the equivalent on Windows
# for EINPROGRESS on Unix.
error = errno.EINPROGRESS
if error != errno.EINPROGRESS:
raise
return 0, sock
except socket.error as e:
sock.close()
return get_exception_errno(e), None
def get_exception_errno(e):
"""A lot of methods on Python socket objects raise socket.error, but that
exception is documented as having two completely different forms of
arguments: either a string or a (errno, string) tuple. We only want the
errno."""
if isinstance(e.args, tuple):
return e.args[0]
else:
return errno.EPROTO
null_fd = -1
def get_null_fd():
"""Returns a readable and writable fd for /dev/null, if successful,
otherwise a negative errno value. The caller must not close the returned
fd (because the same fd will be handed out to subsequent callers)."""
global null_fd
if null_fd < 0:
try:
# os.devnull ensures compatibility with Windows, returns
# '/dev/null' for Unix and 'nul' for Windows
null_fd = os.open(os.devnull, os.O_RDWR)
except OSError as e:
vlog.err("could not open %s: %s" % (os.devnull,
os.strerror(e.errno)))
return -e.errno
return null_fd
def write_fully(fd, buf):
"""Returns an (error, bytes_written) tuple where 'error' is 0 on success,
otherwise a positive errno value, and 'bytes_written' is the number of
bytes that were written before the error occurred. 'error' is 0 if and
only if 'bytes_written' is len(buf)."""
bytes_written = 0
if len(buf) == 0:
return 0, 0
if six.PY3 and not isinstance(buf, six.binary_type):
buf = six.binary_type(buf, 'utf-8')
while True:
try:
retval = os.write(fd, buf)
assert retval >= 0
if retval == len(buf):
return 0, bytes_written + len(buf)
elif retval == 0:
vlog.warn("write returned 0")
return errno.EPROTO, bytes_written
else:
bytes_written += retval
buf = buf[:retval]
except OSError as e:
return e.errno, bytes_written
def set_nonblocking(sock):
try:
sock.setblocking(0)
except socket.error as e:
vlog.err("could not set nonblocking mode on socket: %s"
% os.strerror(get_exception_errno(e)))
def set_dscp(sock, family, dscp):
if dscp > 63:
raise ValueError("Invalid dscp %d" % dscp)
val = dscp << 2
if family == socket.AF_INET:
sock.setsockopt(socket.IPPROTO_IP, socket.IP_TOS, val)
elif family == socket.AF_INET6:
sock.setsockopt(socket.IPPROTO_IPV6, socket.IPV6_TCLASS, val)
else:
raise ValueError('Invalid family %d' % family)
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