A few missing files from the twisted patch

vendor/Twisted-10.0.0/twisted/internet/_sigchld.c

@@ -0,0 +1,101 @@
+/*
+ * Copyright (c) 2010 Twisted Matrix Laboratories.
+ * See LICENSE for details.
+ */
+
+#include <signal.h>
+#include <errno.h>
+
+#include "Python.h"
+
+static int sigchld_pipe_fd = -1;
+
+static void got_signal(int sig) {
+    int saved_errno = errno;
+    int ignored_result;
+
+    /* write() errors are unhandled.  If the buffer is full, we don't
+     * care.  What about other errors? */
+    ignored_result = write(sigchld_pipe_fd, "x", 1);
+
+    errno = saved_errno;
+}
+
+PyDoc_STRVAR(install_sigchld_handler_doc, "\
+install_sigchld_handler(fd)\n\
+\n\
+Installs a SIGCHLD handler which will write a byte to the given fd\n\
+whenever a SIGCHLD occurs. This is done in C code because the python\n\
+signal handling system is not reliable, and additionally cannot\n\
+specify SA_RESTART.\n\
+\n\
+Please ensure fd is in non-blocking mode.\n\
+");
+
+static PyObject *
+install_sigchld_handler(PyObject *self, PyObject *args) {
+    int fd, old_fd;
+    struct sigaction sa;
+
+    if (!PyArg_ParseTuple(args, "i:install_sigchld_handler", &fd)) {
+        return NULL;
+    }
+    old_fd = sigchld_pipe_fd;
+    sigchld_pipe_fd = fd;
+
+    if (fd == -1) {
+        sa.sa_handler = SIG_DFL;
+    } else {
+        sa.sa_handler = got_signal;
+        sa.sa_flags = SA_RESTART;
+        /* mask all signals so I don't worry about EINTR from the write. */
+        sigfillset(&sa.sa_mask);
+    }
+    if (sigaction(SIGCHLD, &sa, 0) != 0) {
+        sigchld_pipe_fd = old_fd;
+        return PyErr_SetFromErrno(PyExc_OSError);
+    }
+    return PyLong_FromLong(old_fd);
+}
+
+PyDoc_STRVAR(is_default_handler_doc, "\
+Return 1 if the SIGCHLD handler is SIG_DFL, 0 otherwise.\n\
+");
+
+static PyObject *
+is_default_handler(PyObject *self, PyObject *args) {
+    /*
+     * This implementation is necessary since the install_sigchld_handler
+     * function above bypasses the Python signal handler installation API, so
+     * CPython doesn't notice that the handler has changed and signal.getsignal
+     * won't return an accurate result.
+     */
+    struct sigaction sa;
+
+    if (sigaction(SIGCHLD, NULL, &sa) != 0) {
+        return PyErr_SetFromErrno(PyExc_OSError);
+    }
+
+    return PyLong_FromLong(sa.sa_handler == SIG_DFL);
+}
+
+static PyMethodDef sigchld_methods[] = {
+    {"installHandler", install_sigchld_handler, METH_VARARGS,
+     install_sigchld_handler_doc},
+    {"isDefaultHandler", is_default_handler, METH_NOARGS,
+     is_default_handler_doc},
+    /* sentinel */
+    {NULL, NULL, 0, NULL}
+};
+
+
+static const char _sigchld_doc[] = "\n\
+This module contains an API for receiving SIGCHLD via a file descriptor.\n\
+";
+
+PyMODINIT_FUNC
+init_sigchld(void) {
+    /* Create the module and add the functions */
+    Py_InitModule3(
+        "twisted.internet._sigchld", sigchld_methods, _sigchld_doc);
+}

vendor/Twisted-10.0.0/twisted/internet/_signals.py

@@ -0,0 +1,184 @@
+# -*- test-case-name: twisted.test.test_process,twisted.internet.test.test_process -*-
+# Copyright (c) 2010 Twisted Matrix Laboratories.
+# See LICENSE for details.
+
+"""
+This module provides a uniform interface to the several mechanisms which are
+possibly available for dealing with signals.
+
+This module is used to integrate child process termination into a
+reactor event loop.  This is a challenging feature to provide because
+most platforms indicate process termination via SIGCHLD and do not
+provide a way to wait for that signal and arbitrary I/O events at the
+same time.  The naive implementation involves installing a Python
+SIGCHLD handler; unfortunately this leads to other syscalls being
+interrupted (whenever SIGCHLD is received) and failing with EINTR
+(which almost no one is prepared to handle).  This interruption can be
+disabled via siginterrupt(2) (or one of the equivalent mechanisms);
+however, if the SIGCHLD is delivered by the platform to a non-main
+thread (not a common occurrence, but difficult to prove impossible),
+the main thread (waiting on select() or another event notification
+API) may not wake up leading to an arbitrary delay before the child
+termination is noticed.
+
+The basic solution to all these issues involves enabling SA_RESTART
+(ie, disabling system call interruption) and registering a C signal
+handler which writes a byte to a pipe.  The other end of the pipe is
+registered with the event loop, allowing it to wake up shortly after
+SIGCHLD is received.  See L{twisted.internet.posixbase._SIGCHLDWaker}
+for the implementation of the event loop side of this solution.  The
+use of a pipe this way is known as the U{self-pipe
+trick<http://cr.yp.to/docs/selfpipe.html>}.
+
+The actual solution implemented in this module depends on the version
+of Python.  From version 2.6, C{signal.siginterrupt} and
+C{signal.set_wakeup_fd} allow the necessary C signal handler which
+writes to the pipe to be registered with C{SA_RESTART}.  Prior to 2.6,
+the L{twisted.internet._sigchld} extension module provides similar
+functionality.
+
+If neither of these is available, a Python signal handler is used
+instead.  This is essentially the naive solution mentioned above and
+has the problems described there.
+"""
+
+import os
+
+try:
+    from signal import set_wakeup_fd, siginterrupt
+except ImportError:
+    set_wakeup_fd = siginterrupt = None
+
+try:
+    import signal
+except ImportError:
+    signal = None
+
+from twisted.python.log import msg
+
+try:
+    from twisted.internet._sigchld import installHandler as _extInstallHandler, \
+        isDefaultHandler as _extIsDefaultHandler
+except ImportError:
+    _extInstallHandler = _extIsDefaultHandler = None
+
+
+class _Handler(object):
+    """
+    L{_Handler} is a signal handler which writes a byte to a file descriptor
+    whenever it is invoked.
+
+    @ivar fd: The file descriptor to which to write.  If this is C{None},
+        nothing will be written.
+    """
+    def __init__(self, fd):
+        self.fd = fd
+
+
+    def __call__(self, *args):
+        """
+        L{_Handler.__call__} is the signal handler.  It will write a byte to
+        the wrapped file descriptor, if there is one.
+        """
+        if self.fd is not None:
+            try:
+                os.write(self.fd, '\0')
+            except:
+                pass
+
+
+
+def _installHandlerUsingSignal(fd):
+    """
+    Install a signal handler which will write a byte to C{fd} when
+    I{SIGCHLD} is received.
+
+    This is implemented by creating an instance of L{_Handler} with C{fd}
+    and installing it as the signal handler.
+
+    @param fd: The file descriptor to which to write when I{SIGCHLD} is
+        received.
+    @type fd: C{int}
+    """
+    if fd == -1:
+        previous = signal.signal(signal.SIGCHLD, signal.SIG_DFL)
+    else:
+        previous = signal.signal(signal.SIGCHLD, _Handler(fd))
+    if isinstance(previous, _Handler):
+        return previous.fd
+    return -1
+
+
+
+def _installHandlerUsingSetWakeup(fd):
+    """
+    Install a signal handler which will write a byte to C{fd} when
+    I{SIGCHLD} is received.
+
+    This is implemented by installing an instance of L{_Handler} wrapped
+    around C{None}, setting the I{SIGCHLD} handler as not allowed to
+    interrupt system calls, and using L{signal.set_wakeup_fd} to do the
+    actual writing.
+
+    @param fd: The file descriptor to which to write when I{SIGCHLD} is
+        received.
+    @type fd: C{int}
+    """
+    if fd == -1:
+        signal.signal(signal.SIGCHLD, signal.SIG_DFL)
+    else:
+        signal.signal(signal.SIGCHLD, _Handler(None))
+        siginterrupt(signal.SIGCHLD, False)
+    return set_wakeup_fd(fd)
+
+
+
+def _isDefaultHandler():
+    """
+    Determine whether the I{SIGCHLD} handler is the default or not.
+    """
+    return signal.getsignal(signal.SIGCHLD) == signal.SIG_DFL
+
+
+
+def _cannotInstallHandler(fd):
+    """
+    Fail to install a signal handler for I{SIGCHLD}.
+
+    This implementation is used when the supporting code for the other
+    implementations is unavailable (on Python versions 2.5 and older where
+    neither the L{twisted.internet._sigchld} extension nor the standard
+    L{signal} module is available).
+
+    @param fd: Ignored; only for compatibility with the other
+        implementations of this interface.
+
+    @raise RuntimeError: Always raised to indicate no I{SIGCHLD} handler can
+        be installed.
+    """
+    raise RuntimeError("Cannot install a SIGCHLD handler")
+
+
+
+def _cannotDetermineDefault():
+    raise RuntimeError("No usable signal API available")
+
+
+
+if set_wakeup_fd is not None:
+    msg('using set_wakeup_fd')
+    installHandler = _installHandlerUsingSetWakeup
+    isDefaultHandler = _isDefaultHandler
+elif _extInstallHandler is not None:
+    msg('using _sigchld')
+    installHandler = _extInstallHandler
+    isDefaultHandler = _extIsDefaultHandler
+elif signal is not None:
+    msg('using signal module')
+    installHandler = _installHandlerUsingSignal
+    isDefaultHandler = _isDefaultHandler
+else:
+    msg('nothing unavailable')
+    installHandler = _cannotInstallHandler
+    isDefaultHandler = _cannotDetermineDefault
+

vendor/Twisted-10.0.0/twisted/internet/test/test_sigchld.py

@@ -0,0 +1,194 @@
+# Copyright (c) 2010 Twisted Matrix Laboratories.
+# See LICENSE for details.
+
+"""
+Tests for L{twisted.internet._sigchld}, an alternate, superior SIGCHLD
+monitoring API.
+"""
+
+import os, signal, errno
+
+from twisted.python.log import msg
+from twisted.trial.unittest import TestCase
+from twisted.internet.fdesc import setNonBlocking
+from twisted.internet._signals import installHandler, isDefaultHandler
+from twisted.internet._signals import _extInstallHandler, _extIsDefaultHandler
+from twisted.internet._signals import _installHandlerUsingSetWakeup, \
+    _installHandlerUsingSignal, _isDefaultHandler
+
+
+class SIGCHLDTestsMixin:
+    """
+    Mixin for L{TestCase} subclasses which defines several tests for
+    I{installHandler} and I{isDefaultHandler}.  Subclasses are expected to
+    define C{self.installHandler} and C{self.isDefaultHandler} to invoke the
+    implementation to be tested.
+    """
+
+    if getattr(signal, 'SIGCHLD', None) is None:
+        skip = "Platform does not have SIGCHLD"
+
+    def installHandler(self, fd):
+        """
+        Override in a subclass to install a SIGCHLD handler which writes a byte
+        to the given file descriptor.  Return the previously registered file
+        descriptor.
+        """
+        raise NotImplementedError()
+
+
+    def isDefaultHandler(self):
+        """
+        Override in a subclass to determine if the current SIGCHLD handler is
+        SIG_DFL or not.  Return True if it is SIG_DFL, False otherwise.
+        """
+        raise NotImplementedError()
+
+
+    def pipe(self):
+        """
+        Create a non-blocking pipe which will be closed after the currently
+        running test.
+        """
+        read, write = os.pipe()
+        self.addCleanup(os.close, read)
+        self.addCleanup(os.close, write)
+        setNonBlocking(read)
+        setNonBlocking(write)
+        return read, write
+
+
+    def setUp(self):
+        """
+        Save the current SIGCHLD handler as reported by L{signal.signal} and
+        the current file descriptor registered with L{installHandler}.
+        """
+        handler = signal.getsignal(signal.SIGCHLD)
+        if handler != signal.SIG_DFL:
+            self.signalModuleHandler = handler
+            signal.signal(signal.SIGCHLD, signal.SIG_DFL)
+        else:
+            self.signalModuleHandler = None
+
+        self.oldFD = self.installHandler(-1)
+
+        if self.signalModuleHandler is not None and self.oldFD != -1:
+            msg("SIGCHLD setup issue: %r %r" % (self.signalModuleHandler, self.oldFD))
+            raise RuntimeError("You used some signal APIs wrong!  Try again.")
+
+
+    def tearDown(self):
+        """
+        Restore whatever signal handler was present when setUp ran.
+        """
+        # If tests set up any kind of handlers, clear them out.
+        self.installHandler(-1)
+        signal.signal(signal.SIGCHLD, signal.SIG_DFL)
+
+        # Now restore whatever the setup was before the test ran.
+        if self.signalModuleHandler is not None:
+            signal.signal(signal.SIGCHLD, self.signalModuleHandler)
+        elif self.oldFD != -1:
+            self.installHandler(self.oldFD)
+
+
+    def test_isDefaultHandler(self):
+        """
+        L{isDefaultHandler} returns true if the SIGCHLD handler is SIG_DFL,
+        false otherwise.
+        """
+        self.assertTrue(self.isDefaultHandler())
+        signal.signal(signal.SIGCHLD, signal.SIG_IGN)
+        self.assertFalse(self.isDefaultHandler())
+        signal.signal(signal.SIGCHLD, signal.SIG_DFL)
+        self.assertTrue(self.isDefaultHandler())
+        signal.signal(signal.SIGCHLD, lambda *args: None)
+        self.assertFalse(self.isDefaultHandler())
+
+
+    def test_returnOldFD(self):
+        """
+        L{installHandler} returns the previously registered file descriptor.
+        """
+        read, write = self.pipe()
+        oldFD = self.installHandler(write)
+        self.assertEqual(self.installHandler(oldFD), write)
+
+
+    def test_uninstallHandler(self):
+        """
+        C{installHandler(-1)} removes the SIGCHLD handler completely.
+        """
+        read, write = self.pipe()
+        self.assertTrue(self.isDefaultHandler())
+        self.installHandler(write)
+        self.assertFalse(self.isDefaultHandler())
+        self.installHandler(-1)
+        self.assertTrue(self.isDefaultHandler())
+
+
+    def test_installHandler(self):
+        """
+        The file descriptor passed to L{installHandler} has a byte written to
+        it when SIGCHLD is delivered to the process.
+        """
+        read, write = self.pipe()
+        self.installHandler(write)
+
+        exc = self.assertRaises(OSError, os.read, read, 1)
+        self.assertEqual(exc.errno, errno.EAGAIN)
+
+        os.kill(os.getpid(), signal.SIGCHLD)
+
+        self.assertEqual(len(os.read(read, 5)), 1)
+
+
+
+class DefaultSIGCHLDTests(SIGCHLDTestsMixin, TestCase):
+    """
+    Tests for whatever implementation is selected for the L{installHandler}
+    and L{isDefaultHandler} APIs.
+    """
+    installHandler = staticmethod(installHandler)
+    isDefaultHandler = staticmethod(isDefaultHandler)
+
+
+
+class ExtensionSIGCHLDTests(SIGCHLDTestsMixin, TestCase):
+    """
+    Tests for the L{twisted.internet._sigchld} implementation of the
+    L{installHandler} and L{isDefaultHandler} APIs.
+    """
+    try:
+        import twisted.internet._sigchld
+    except ImportError:
+        skip = "twisted.internet._sigchld is not available"
+
+    installHandler = _extInstallHandler
+    isDefaultHandler = _extIsDefaultHandler
+
+
+
+class SetWakeupSIGCHLDTests(SIGCHLDTestsMixin, TestCase):
+    """
+    Tests for the L{signal.set_wakeup_fd} implementation of the
+    L{installHandler} and L{isDefaultHandler} APIs.
+    """
+    # Check both of these.  On Ubuntu 9.10 (to take an example completely at
+    # random), Python 2.5 has set_wakeup_fd but not siginterrupt.
+    if (getattr(signal, 'set_wakeup_fd', None) is None
+        or getattr(signal, 'siginterrupt', None) is None):
+        skip = "signal.set_wakeup_fd is not available"
+
+    installHandler = staticmethod(_installHandlerUsingSetWakeup)
+    isDefaultHandler = staticmethod(_isDefaultHandler)
+
+
+
+class PlainSignalModuleSIGCHLDTests(SIGCHLDTestsMixin, TestCase):
+    """
+    Tests for the L{signal.signal} implementation of the L{installHandler}
+    and L{isDefaultHandler} APIs.
+    """
+    installHandler = staticmethod(_installHandlerUsingSignal)
+    isDefaultHandler = staticmethod(_isDefaultHandler)

vendor/Twisted-10.0.0/twisted/topfiles/733.bugfix

@@ -0,0 +1,4 @@
+On POSIX platforms, reactors now support child processes in a way
+which doesn't cause other syscalls to sometimes fail with EINTR (if
+running on Python 2.6 or if Twisted's extension modules have been
+built).