1 # Copyright (c) 2010, 2012 Nicira, Inc.
3 # Licensed under the Apache License, Version 2.0 (the "License");
4 # you may not use this file except in compliance with the License.
5 # You may obtain a copy of the License at:
7 # http://www.apache.org/licenses/LICENSE-2.0
9 # Unless required by applicable law or agreed to in writing, software
10 # distributed under the License is distributed on an "AS IS" BASIS,
11 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 # See the License for the specific language governing permissions and
13 # limitations under the License.
23 import ovs.fatal_signal
27 vlog = ovs.vlog.Vlog("socket_util")
30 def make_short_name(long_name):
33 long_name = os.path.abspath(long_name)
34 long_dirname = os.path.dirname(long_name)
35 tmpdir = os.getenv('TMPDIR', '/tmp')
36 for x in xrange(0, 1000):
38 '%s/ovs-un-py-%d-%d' % (tmpdir, random.randint(0, 10000), x)
40 os.symlink(long_dirname, link_name)
41 ovs.fatal_signal.add_file_to_unlink(link_name)
42 return os.path.join(link_name, os.path.basename(long_name))
44 if e.errno != errno.EEXIST:
46 raise Exception("Failed to create temporary symlink")
49 def free_short_name(short_name):
50 if short_name is None:
52 link_name = os.path.dirname(short_name)
53 ovs.fatal_signal.unlink_file_now(link_name)
56 def make_unix_socket(style, nonblock, bind_path, connect_path, short=False):
57 """Creates a Unix domain socket in the given 'style' (either
58 socket.SOCK_DGRAM or socket.SOCK_STREAM) that is bound to 'bind_path' (if
59 'bind_path' is not None) and connected to 'connect_path' (if 'connect_path'
60 is not None). If 'nonblock' is true, the socket is made non-blocking.
62 Returns (error, socket): on success 'error' is 0 and 'socket' is a new
63 socket object, on failure 'error' is a positive errno value and 'socket' is
67 sock = socket.socket(socket.AF_UNIX, style)
68 except socket.error, e:
69 return get_exception_errno(e), None
74 if bind_path is not None:
75 # Delete bind_path but ignore ENOENT.
79 if e.errno != errno.ENOENT:
82 ovs.fatal_signal.add_file_to_unlink(bind_path)
86 if sys.hexversion >= 0x02060000:
87 os.fchmod(sock.fileno(), 0700)
89 os.chmod("/dev/fd/%d" % sock.fileno(), 0700)
92 if connect_path is not None:
94 sock.connect(connect_path)
95 except socket.error, e:
96 if get_exception_errno(e) != errno.EINPROGRESS:
99 except socket.error, e:
101 if (bind_path is not None and
102 os.path.exists(bind_path)):
103 ovs.fatal_signal.unlink_file_now(bind_path)
104 eno = ovs.socket_util.get_exception_errno(e)
105 if (eno == "AF_UNIX path too long" and
106 os.uname()[0] == "Linux"):
107 short_connect_path = None
108 short_bind_path = None
111 # Try workaround using /proc/self/fd
112 if connect_path is not None:
113 dirname = os.path.dirname(connect_path)
114 basename = os.path.basename(connect_path)
116 connect_dirfd = os.open(dirname, os.O_DIRECTORY | os.O_RDONLY)
118 return get_exception_errno(err), None
119 short_connect_path = "/proc/self/fd/%d/%s" % (connect_dirfd, basename)
121 if bind_path is not None:
122 dirname = os.path.dirname(bind_path)
123 basename = os.path.basename(bind_path)
125 bind_dirfd = os.open(dirname, os.O_DIRECTORY | os.O_RDONLY)
127 return get_exception_errno(err), None
128 short_bind_path = "/proc/self/fd/%d/%s" % (bind_dirfd, basename)
131 return make_unix_socket(style, nonblock, short_bind_path, short_connect_path)
133 if connect_dirfd is not None:
134 os.close(connect_dirfd)
135 if bind_dirfd is not None:
137 elif (eno == "AF_UNIX path too long"):
139 return get_exception_errno(e), None
140 short_bind_path = None
142 short_bind_path = make_short_name(bind_path)
143 short_connect_path = make_short_name(connect_path)
145 free_short_name(short_bind_path)
146 return errno.ENAMETOOLONG, None
148 return make_unix_socket(style, nonblock, short_bind_path,
149 short_connect_path, short=True)
151 free_short_name(short_bind_path)
152 free_short_name(short_connect_path)
154 return get_exception_errno(e), None
157 def check_connection_completion(sock):
158 p = ovs.poller.SelectPoll()
159 p.register(sock, ovs.poller.POLLOUT)
163 if revents & ovs.poller.POLLERR:
165 # The following should raise an exception.
166 socket.send("\0", socket.MSG_DONTWAIT)
168 # (Here's where we end up if it didn't.)
170 vlog.err("poll return POLLERR but send succeeded")
172 except socket.error, e:
173 return get_exception_errno(e)
180 def inet_parse_active(target, default_port):
181 address = target.split(":")
182 host_name = address[0]
184 raise ValueError("%s: bad peer name format" % target)
185 if len(address) >= 2:
186 port = int(address[1])
190 raise ValueError("%s: port number must be specified" % target)
191 return (host_name, port)
194 def inet_open_active(style, target, default_port, dscp):
195 address = inet_parse_active(target, default_port)
197 sock = socket.socket(socket.AF_INET, style, 0)
198 except socket.error, e:
199 return get_exception_errno(e), None
202 set_nonblocking(sock)
205 sock.connect(address)
206 except socket.error, e:
207 if get_exception_errno(e) != errno.EINPROGRESS:
210 except socket.error, e:
212 return get_exception_errno(e), None
215 def get_exception_errno(e):
216 """A lot of methods on Python socket objects raise socket.error, but that
217 exception is documented as having two completely different forms of
218 arguments: either a string or a (errno, string) tuple. We only want the
220 if type(e.args) == tuple:
230 """Returns a readable and writable fd for /dev/null, if successful,
231 otherwise a negative errno value. The caller must not close the returned
232 fd (because the same fd will be handed out to subsequent callers)."""
236 null_fd = os.open("/dev/null", os.O_RDWR)
238 vlog.err("could not open /dev/null: %s" % os.strerror(e.errno))
243 def write_fully(fd, buf):
244 """Returns an (error, bytes_written) tuple where 'error' is 0 on success,
245 otherwise a positive errno value, and 'bytes_written' is the number of
246 bytes that were written before the error occurred. 'error' is 0 if and
247 only if 'bytes_written' is len(buf)."""
253 retval = os.write(fd, buf)
255 if retval == len(buf):
256 return 0, bytes_written + len(buf)
258 vlog.warn("write returned 0")
259 return errno.EPROTO, bytes_written
261 bytes_written += retval
264 return e.errno, bytes_written
267 def set_nonblocking(sock):
270 except socket.error, e:
271 vlog.err("could not set nonblocking mode on socket: %s"
272 % os.strerror(get_exception_errno(e)))
275 def set_dscp(sock, dscp):
277 raise ValueError("Invalid dscp %d" % dscp)
279 sock.setsockopt(socket.IPPROTO_IP, socket.IP_TOS, val)