# Copyright (c) Twisted Matrix Laboratories.
# See LICENSE for details.

"""
Tests for L{twisted.python.sendmsg}.
"""

import sys
import errno

from socket import SOL_SOCKET, AF_INET, AF_INET6, socket, error

try:
from socket import AF_UNIX, socketpair
except ImportError:
nonUNIXSkip = "Platform does not support AF_UNIX sockets"
else:
nonUNIXSkip = None

from struct import pack
from os import devnull, pipe, read, close, environ

from twisted.internet.defer import Deferred
from twisted.internet.error import ProcessDone
from twisted.trial.unittest import TestCase
from twisted.internet.defer import inlineCallbacks
from twisted.internet import reactor
from twisted.python.filepath import FilePath
from twisted.python.runtime import platform

from twisted.internet.protocol import ProcessProtocol

if platform.isLinux():
from socket import MSG_DONTWAIT
dontWaitSkip = None
else:
# It would be nice to be able to test flags on more platforms, but finding a
# flag that works *at all* is somewhat challenging.
dontWaitSkip = "MSG_DONTWAIT is only known to work as intended on Linux"

try:
from twisted.python.sendmsg import SCM_RIGHTS, send1msg, recv1msg, getsockfam
except ImportError:
importSkip = "Cannot import twisted.python.sendmsg"
else:
importSkip = None


class ExitedWithStderr(Exception):
"""
A process exited with some stderr.
"""

def __str__(self):
"""
Dump the errors in a pretty way in the event of a subprocess traceback.
"""
return '\n'.join([''] + list(self.args))


class StartStopProcessProtocol(ProcessProtocol):
"""
An L{IProcessProtocol} with a Deferred for events where the subprocess
starts and stops.

@ivar started: A L{Deferred} which fires with this protocol's
L{IProcessTransport} provider when it is connected to one.

@ivar stopped: A L{Deferred} which fires with the process output or a
failure if the process produces output on standard error.

@ivar output: A C{str} used to accumulate standard output.

@ivar errors: A C{str} used to accumulate standard error.
"""
def __init__(self):
self.started = Deferred()
self.stopped = Deferred()
self.output = ''
self.errors = ''


def connectionMade(self):
self.started.callback(self.transport)


def outReceived(self, data):
self.output += data


def errReceived(self, data):
self.errors += data


def processEnded(self, reason):
if reason.check(ProcessDone):
self.stopped.callback(self.output)
else:
self.stopped.errback(ExitedWithStderr(
self.errors, self.output))



class BadList(list):
"""
A list which cannot be iterated sometimes.

This is a C{list} subclass to get past the type check in L{send1msg}, not as
an example of how real programs might want to interact with L{send1msg} (or
anything else). A custom C{list} subclass makes it easier to trigger
certain error cases in the implementation.

@ivar iterate: A flag which indicates whether an instance of L{BadList} will
allow iteration over itself or not. If C{False}, an attempt to iterate
over the instance will raise an exception.
"""
iterate = True

def __iter__(self):
"""
Allow normal list iteration, or raise an exception.

If C{self.iterate} is C{True}, it will be flipped to C{False} and then
normal iteration will proceed. If C{self.iterate} is C{False},
L{RuntimeError} is raised instead.
"""
if self.iterate:
self.iterate = False
return super(BadList, self).__iter__()
raise RuntimeError("Something bad happened")



class WorseList(list):
"""
A list which at first gives the appearance of being iterable, but then
raises an exception.

See L{BadList} for a warning about not writing code like this.
"""
def __iter__(self):
"""
Return an iterator which will raise an exception as soon as C{next} is
called on it.
"""
class BadIterator(object):
def next(self):
raise RuntimeError("This is a really bad case.")
return BadIterator()



class SendmsgTestCase(TestCase):
"""
Tests for sendmsg extension module and associated file-descriptor sending
functionality.
"""
if nonUNIXSkip is not None:
skip = nonUNIXSkip
elif importSkip is not None:
skip = importSkip

def setUp(self):
"""
Create a pair of UNIX sockets.
"""
self.input, self.output = socketpair(AF_UNIX)


def tearDown(self):
"""
Close the sockets opened by setUp.
"""
self.input.close()
self.output.close()


def test_sendmsgBadArguments(self):
"""
The argument types accepted by L{send1msg} are:

1. C{int}
2. read-only character buffer
3. C{int}
4. sequence

The 3rd and 4th arguments are optional. If fewer than two arguments or
more than four arguments are passed, or if any of the arguments passed
are not compatible with these types, L{TypeError} is raised.
"""
# Exercise the wrong number of arguments cases
self.assertRaises(TypeError, send1msg)
self.assertRaises(TypeError, send1msg, 1)
self.assertRaises(TypeError, send1msg, 1, "hello world", 2, [], object())

# Exercise the wrong type of arguments cases
self.assertRaises(TypeError, send1msg, object(), "hello world", 2, [])
self.assertRaises(TypeError, send1msg, 1, object(), 2, [])
self.assertRaises(TypeError, send1msg, 1, "hello world", object(), [])
self.assertRaises(TypeError, send1msg, 1, "hello world", 2, object())


def test_badAncillaryIter(self):
"""
If iteration over the ancillary data list fails (at the point of the
C{__iter__} call), the exception with which it fails is propagated to
the caller of L{send1msg}.
"""
badList = BadList()
badList.append((1, 2, "hello world"))
badList.iterate = False

self.assertRaises(RuntimeError, send1msg, 1, "hello world", 2, badList)

# Hit the second iteration
badList.iterate = True
self.assertRaises(RuntimeError, send1msg, 1, "hello world", 2, badList)


def test_badAncillaryNext(self):
"""
If iteration over the ancillary data list fails (at the point of a
C{next} call), the exception with which it fails is propagated to the
caller of L{send1msg}.
"""
worseList = WorseList()
self.assertRaises(RuntimeError, send1msg, 1, "hello world", 2, worseList)


def test_sendmsgBadAncillaryItem(self):
"""
The ancillary data list contains three-tuples with element types of:

1. C{int}
2. C{int}
3. read-only character buffer

If a tuple in the ancillary data list does not elements of these types,
L{TypeError} is raised.
"""
# Exercise the wrong number of arguments cases
self.assertRaises(TypeError, send1msg, 1, "hello world", 2, [()])
self.assertRaises(TypeError, send1msg, 1, "hello world", 2, [(1,)])
self.assertRaises(TypeError, send1msg, 1, "hello world", 2, [(1, 2)])
self.assertRaises(
TypeError,
send1msg, 1, "hello world", 2, [(1, 2, "goodbye", object())])

# Exercise the wrong type of arguments cases
exc = self.assertRaises(
TypeError, send1msg, 1, "hello world", 2, [object()])
self.assertEqual(
"send1msg argument 3 expected list of tuple, "
"got list containing object",
str(exc))
self.assertRaises(
TypeError,
send1msg, 1, "hello world", 2, [(object(), 1, "goodbye")])
self.assertRaises(
TypeError,
send1msg, 1, "hello world", 2, [(1, object(), "goodbye")])
self.assertRaises(
TypeError,
send1msg, 1, "hello world", 2, [(1, 1, object())])


def test_syscallError(self):
"""
If the underlying C{sendmsg} call fails, L{send1msg} raises
L{socket.error} with its errno set to the underlying errno value.
"""
probe = file(devnull)
fd = probe.fileno()
probe.close()
exc = self.assertRaises(error, send1msg, fd, "hello, world")
self.assertEqual(exc.args[0], errno.EBADF)


def test_syscallErrorWithControlMessage(self):
"""
The behavior when the underlying C{sendmsg} call fails is the same
whether L{send1msg} is passed ancillary data or not.
"""
probe = file(devnull)
fd = probe.fileno()
probe.close()
exc = self.assertRaises(
error, send1msg, fd, "hello, world", 0, [(0, 0, "0123")])
self.assertEqual(exc.args[0], errno.EBADF)


def test_roundtrip(self):
"""
L{recv1msg} will retrieve a message sent via L{send1msg}.
"""
message = "hello, world!"
self.assertEqual(
len(message),
send1msg(self.input.fileno(), message, 0))

result = recv1msg(fd=self.output.fileno())
self.assertEquals(result, (message, 0, []))


def test_shortsend(self):
"""
L{send1msg} returns the number of bytes which it was able to send.
"""
message = "x" * 1024 * 1024
self.input.setblocking(False)
sent = send1msg(self.input.fileno(), message)
# Sanity check - make sure we did fill the send buffer and then some
self.assertTrue(sent < len(message))
received = recv1msg(self.output.fileno(), 0, len(message))
self.assertEqual(len(received[0]), sent)


def test_roundtripEmptyAncillary(self):
"""
L{send1msg} treats an empty ancillary data list the same way it treats
receiving no argument for the ancillary parameter at all.
"""
send1msg(self.input.fileno(), "hello, world!", 0, [])

result = recv1msg(fd=self.output.fileno())
self.assertEquals(result, ("hello, world!", 0, []))


def test_flags(self):
"""
The C{flags} argument to L{send1msg} is passed on to the underlying
C{sendmsg} call, to affect it in whatever way is defined by those flags.
"""
# Just exercise one flag with simple, well-known behavior. MSG_DONTWAIT
# makes the send a non-blocking call, even if the socket is in blocking
# mode. See also test_flags in RecvmsgTestCase
for i in range(1024):
try:
send1msg(self.input.fileno(), "x" * 1024, MSG_DONTWAIT)
except error, e:
self.assertEqual(e.args[0], errno.EAGAIN)
break
else:
self.fail(
"Failed to fill up the send buffer, "
"or maybe send1msg blocked for a while")
if dontWaitSkip is not None:
test_flags.skip = dontWaitSkip


def test_wrongTypeAncillary(self):
"""
L{send1msg} will show a helpful exception message when given the wrong
type of object for the 'ancillary' argument.
"""
error = self.assertRaises(TypeError,
send1msg, self.input.fileno(),
"hello, world!", 0, 4321)
self.assertEquals(str(error),
"send1msg argument 3 expected list, got int")


def spawn(self, script):
"""
Start a script that is a peer of this test as a subprocess.

@param script: the module name of the script in this directory (no
package prefix, no '.py')
@type script: C{str}

@rtype: L{StartStopProcessProtocol}
"""
sspp = StartStopProcessProtocol()
reactor.spawnProcess(
sspp, sys.executable, [
sys.executable,
FilePath(__file__).sibling(script + ".py").path,
str(self.output.fileno()),
],
environ,
childFDs={0: "w", 1: "r", 2: "r",
self.output.fileno(): self.output.fileno()}
)
return sspp


@inlineCallbacks
def test_sendSubProcessFD(self):
"""
Calling L{sendsmsg} with SOL_SOCKET, SCM_RIGHTS, and a platform-endian
packed file descriptor number should send that file descriptor to a
different process, where it can be retrieved by using L{recv1msg}.
"""
sspp = self.spawn("pullpipe")
yield sspp.started
pipeOut, pipeIn = pipe()
self.addCleanup(close, pipeOut)

send1msg(
self.input.fileno(), "blonk", 0,
[(SOL_SOCKET, SCM_RIGHTS, pack("i", pipeIn))])

close(pipeIn)
yield sspp.stopped
self.assertEquals(read(pipeOut, 1024), "Test fixture data: blonk.\n")
# Make sure that the pipe is actually closed now.
self.assertEquals(read(pipeOut, 1024), "")



class RecvmsgTestCase(TestCase):
"""
Tests for L{recv1msg} (primarily error handling cases).
"""
if importSkip is not None:
skip = importSkip

def test_badArguments(self):
"""
The argument types accepted by L{recv1msg} are:

1. C{int}
2. C{int}
3. C{int}
4. C{int}

The 2nd, 3rd, and 4th arguments are optional. If fewer than one
argument or more than four arguments are passed, or if any of the
arguments passed are not compatible with these types, L{TypeError} is
raised.
"""
# Exercise the wrong number of arguments cases
self.assertRaises(TypeError, recv1msg)
self.assertRaises(TypeError, recv1msg, 1, 2, 3, 4, object())

# Exercise the wrong type of arguments cases
self.assertRaises(TypeError, recv1msg, object(), 2, 3, 4)
self.assertRaises(TypeError, recv1msg, 1, object(), 3, 4)
self.assertRaises(TypeError, recv1msg, 1, 2, object(), 4)
self.assertRaises(TypeError, recv1msg, 1, 2, 3, object())


def test_cmsgSpaceOverflow(self):
"""
L{recv1msg} raises L{OverflowError} if passed a value for the
C{cmsg_size} argument which exceeds C{SOCKLEN_MAX}.
"""
self.assertRaises(OverflowError, recv1msg, 0, 0, 0, 0x7FFFFFFF)


def test_syscallError(self):
"""
If the underlying C{recvmsg} call fails, L{recv1msg} raises
L{socket.error} with its errno set to the underlying errno value.
"""
probe = file(devnull)
fd = probe.fileno()
probe.close()
exc = self.assertRaises(error, recv1msg, fd)
self.assertEqual(exc.args[0], errno.EBADF)


def test_flags(self):
"""
The C{flags} argument to L{recv1msg} is passed on to the underlying
C{recvmsg} call, to affect it in whatever way is defined by those flags.
"""
# See test_flags in SendmsgTestCase
reader, writer = socketpair(AF_UNIX)
exc = self.assertRaises(
error, recv1msg, reader.fileno(), MSG_DONTWAIT)
self.assertEqual(exc.args[0], errno.EAGAIN)
if dontWaitSkip is not None:
test_flags.skip = dontWaitSkip



class GetSocketFamilyTests(TestCase):
"""
Tests for L{getsockfam}, a helper which reveals the address family of an
arbitrary socket.
"""
if importSkip is not None:
skip = importSkip

def _socket(self, addressFamily):
"""
Create a new socket using the given address family and return that
socket's file descriptor. The socket will automatically be closed when
the test is torn down.
"""
s = socket(addressFamily)
self.addCleanup(s.close)
return s.fileno()


def test_badArguments(self):
"""
L{getsockfam} accepts a single C{int} argument. If it is called in some
other way, L{TypeError} is raised.
"""
self.assertRaises(TypeError, getsockfam)
self.assertRaises(TypeError, getsockfam, 1, 2)

self.assertRaises(TypeError, getsockfam, object())


def test_syscallError(self):
"""
If the underlying C{getsockname} call fails, L{getsockfam} raises
L{socket.error} with its errno set to the underlying errno value.
"""
probe = file(devnull)
fd = probe.fileno()
probe.close()
exc = self.assertRaises(error, getsockfam, fd)
self.assertEqual(errno.EBADF, exc.args[0])


def test_inet(self):
"""
When passed the file descriptor of a socket created with the C{AF_INET}
address family, L{getsockfam} returns C{AF_INET}.
"""
self.assertEqual(AF_INET, getsockfam(self._socket(AF_INET)))


def test_inet6(self):
"""
When passed the file descriptor of a socket created with the C{AF_INET6}
address family, L{getsockfam} returns C{AF_INET6}.
"""
self.assertEqual(AF_INET6, getsockfam(self._socket(AF_INET6)))


def test_unix(self):
"""
When passed the file descriptor of a socket created with the C{AF_UNIX}
address family, L{getsockfam} returns C{AF_UNIX}.
"""
self.assertEqual(AF_UNIX, getsockfam(self._socket(AF_UNIX)))
if nonUNIXSkip is not None:
test_unix.skip = nonUNIXSkip