/*  @file
  select - Module containing unix select(2) call.
  Under Unix, the file descriptors are small integers.
  Under Win32, select only exists for sockets, and sockets may
  have any value except INVALID_SOCKET.
  Under BeOS, we suffer the same dichotomy as Win32; sockets can be anything
  >= 0.

  Copyright (c) 2015, Daryl McDaniel. All rights reserved.<BR>
  Copyright (c) 2011 - 2012, Intel Corporation. All rights reserved.<BR>
  This program and the accompanying materials are licensed and made available under
  the terms and conditions of the BSD License that accompanies this distribution.
  The full text of the license may be found at
  http://opensource.org/licenses/bsd-license.

  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
*/

#include "Python.h"
#include <structmember.h>

#ifdef __APPLE__
    /* Perform runtime testing for a broken poll on OSX to make it easier
     * to use the same binary on multiple releases of the OS.
     */
#undef HAVE_BROKEN_POLL
#endif

/* Windows #defines FD_SETSIZE to 64 if FD_SETSIZE isn't already defined.
   64 is too small (too many people have bumped into that limit).
   Here we boost it.
   Users who want even more than the boosted limit should #define
   FD_SETSIZE higher before this; e.g., via compiler /D switch.
*/
#if defined(MS_WINDOWS) && !defined(FD_SETSIZE)
#define FD_SETSIZE 512
#endif

#if defined(HAVE_POLL_H)
#include <poll.h>
#elif defined(HAVE_SYS_POLL_H)
#include <sys/poll.h>
#endif

#ifdef __sgi
/* This is missing from unistd.h */
extern void bzero(void *, int);
#endif

#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif

#if defined(PYOS_OS2) && !defined(PYCC_GCC)
#include <sys/time.h>
#include <utils.h>
#endif

#ifdef MS_WINDOWS
#  include <winsock2.h>
#else
#  define SOCKET int
#  ifdef __BEOS__
#    include <net/socket.h>
#  elif defined(__VMS)
#    include <socket.h>
#  endif
#endif

static PyObject *SelectError;

/* list of Python objects and their file descriptor */
typedef struct {
    PyObject *obj;                           /* owned reference */
    SOCKET fd;
    int sentinel;                            /* -1 == sentinel */
} pylist;

static void
reap_obj(pylist fd2obj[FD_SETSIZE + 1])
{
    int i;
    for (i = 0; i < FD_SETSIZE + 1 && fd2obj[i].sentinel >= 0; i++) {
        Py_CLEAR(fd2obj[i].obj);
    }
    fd2obj[0].sentinel = -1;
}


/* returns -1 and sets the Python exception if an error occurred, otherwise
   returns a number >= 0
*/
static int
seq2set(PyObject *seq, fd_set *set, pylist fd2obj[FD_SETSIZE + 1])
{
    int i;
    int max = -1;
    int index = 0;
    PyObject* fast_seq = NULL;
    PyObject* o = NULL;

    fd2obj[0].obj = (PyObject*)0;            /* set list to zero size */
    FD_ZERO(set);

    fast_seq = PySequence_Fast(seq, "arguments 1-3 must be sequences");
    if (!fast_seq)
        return -1;

    for (i = 0; i < PySequence_Fast_GET_SIZE(fast_seq); i++)  {
        SOCKET v;

        /* any intervening fileno() calls could decr this refcnt */
        if (!(o = PySequence_Fast_GET_ITEM(fast_seq, i)))
            return -1;

        Py_INCREF(o);
        v = PyObject_AsFileDescriptor( o );
        if (v == -1) goto finally;

#if defined(_MSC_VER) && !defined(UEFI_C_SOURCE)
        max = 0;                             /* not used for Win32 */
#else  /* !_MSC_VER */
        if (!_PyIsSelectable_fd(v)) {
            PyErr_SetString(PyExc_ValueError,
                        "filedescriptor out of range in select()");
            goto finally;
        }
        if (v > max)
            max = v;
#endif /* _MSC_VER */
        FD_SET(v, set);

        /* add object and its file descriptor to the list */
        if (index >= FD_SETSIZE) {
            PyErr_SetString(PyExc_ValueError,
                          "too many file descriptors in select()");
            goto finally;
        }
        fd2obj[index].obj = o;
        fd2obj[index].fd = v;
        fd2obj[index].sentinel = 0;
        fd2obj[++index].sentinel = -1;
    }
    Py_DECREF(fast_seq);
    return max+1;

  finally:
    Py_XDECREF(o);
    Py_DECREF(fast_seq);
    return -1;
}

/* returns NULL and sets the Python exception if an error occurred */
static PyObject *
set2list(fd_set *set, pylist fd2obj[FD_SETSIZE + 1])
{
    int i, j, count=0;
    PyObject *list, *o;
    SOCKET fd;

    for (j = 0; fd2obj[j].sentinel >= 0; j++) {
        if (FD_ISSET(fd2obj[j].fd, set))
            count++;
    }
    list = PyList_New(count);
    if (!list)
        return NULL;

    i = 0;
    for (j = 0; fd2obj[j].sentinel >= 0; j++) {
        fd = fd2obj[j].fd;
        if (FD_ISSET(fd, set)) {
            o = fd2obj[j].obj;
            fd2obj[j].obj = NULL;
            /* transfer ownership */
            if (PyList_SetItem(list, i, o) < 0)
                goto finally;

            i++;
        }
    }
    return list;
  finally:
    Py_DECREF(list);
    return NULL;
}

#undef SELECT_USES_HEAP
#if FD_SETSIZE > 1024
#define SELECT_USES_HEAP
#endif /* FD_SETSIZE > 1024 */

static PyObject *
select_select(PyObject *self, PyObject *args)
{
#ifdef SELECT_USES_HEAP
    pylist *rfd2obj, *wfd2obj, *efd2obj;
#else  /* !SELECT_USES_HEAP */
    /* XXX: All this should probably be implemented as follows:
     * - find the highest descriptor we're interested in
     * - add one
     * - that's the size
     * See: Stevens, APitUE, $12.5.1
     */
    pylist rfd2obj[FD_SETSIZE + 1];
    pylist wfd2obj[FD_SETSIZE + 1];
    pylist efd2obj[FD_SETSIZE + 1];
#endif /* SELECT_USES_HEAP */
    PyObject *ifdlist, *ofdlist, *efdlist;
    PyObject *ret = NULL;
    PyObject *tout = Py_None;
    fd_set ifdset, ofdset, efdset;
    double timeout;
    struct timeval tv, *tvp;
    long seconds;
    int imax, omax, emax, max;
    int n;

    /* convert arguments */
    if (!PyArg_UnpackTuple(args, "select", 3, 4,
                          &ifdlist, &ofdlist, &efdlist, &tout))
        return NULL;

    if (tout == Py_None)
        tvp = (struct timeval *)0;
    else if (!PyNumber_Check(tout)) {
        PyErr_SetString(PyExc_TypeError,
                        "timeout must be a float or None");
        return NULL;
    }
    else {
        timeout = PyFloat_AsDouble(tout);
        if (timeout == -1 && PyErr_Occurred())
            return NULL;
        if (timeout > (double)LONG_MAX) {
            PyErr_SetString(PyExc_OverflowError,
                            "timeout period too long");
            return NULL;
        }
        seconds = (long)timeout;
        timeout = timeout - (double)seconds;
        tv.tv_sec = seconds;
        tv.tv_usec = (long)(timeout * 1E6);
        tvp = &tv;
    }


#ifdef SELECT_USES_HEAP
    /* Allocate memory for the lists */
    rfd2obj = PyMem_NEW(pylist, FD_SETSIZE + 1);
    wfd2obj = PyMem_NEW(pylist, FD_SETSIZE + 1);
    efd2obj = PyMem_NEW(pylist, FD_SETSIZE + 1);
    if (rfd2obj == NULL || wfd2obj == NULL || efd2obj == NULL) {
        if (rfd2obj) PyMem_DEL(rfd2obj);
        if (wfd2obj) PyMem_DEL(wfd2obj);
        if (efd2obj) PyMem_DEL(efd2obj);
        return PyErr_NoMemory();
    }
#endif /* SELECT_USES_HEAP */
    /* Convert sequences to fd_sets, and get maximum fd number
     * propagates the Python exception set in seq2set()
     */
    rfd2obj[0].sentinel = -1;
    wfd2obj[0].sentinel = -1;
    efd2obj[0].sentinel = -1;
    if ((imax=seq2set(ifdlist, &ifdset, rfd2obj)) < 0)
        goto finally;
    if ((omax=seq2set(ofdlist, &ofdset, wfd2obj)) < 0)
        goto finally;
    if ((emax=seq2set(efdlist, &efdset, efd2obj)) < 0)
        goto finally;
    max = imax;
    if (omax > max) max = omax;
    if (emax > max) max = emax;

    Py_BEGIN_ALLOW_THREADS
    n = select(max, &ifdset, &ofdset, &efdset, tvp);
    Py_END_ALLOW_THREADS

#ifdef MS_WINDOWS
    if (n == SOCKET_ERROR) {
        PyErr_SetExcFromWindowsErr(SelectError, WSAGetLastError());
    }
#else
    if (n < 0) {
        PyErr_SetFromErrno(SelectError);
    }
#endif
    else {
        /* any of these three calls can raise an exception.  it's more
           convenient to test for this after all three calls... but
           is that acceptable?
        */
        ifdlist = set2list(&ifdset, rfd2obj);
        ofdlist = set2list(&ofdset, wfd2obj);
        efdlist = set2list(&efdset, efd2obj);
        if (PyErr_Occurred())
            ret = NULL;
        else
            ret = PyTuple_Pack(3, ifdlist, ofdlist, efdlist);

        Py_DECREF(ifdlist);
        Py_DECREF(ofdlist);
        Py_DECREF(efdlist);
    }

  finally:
    reap_obj(rfd2obj);
    reap_obj(wfd2obj);
    reap_obj(efd2obj);
#ifdef SELECT_USES_HEAP
    PyMem_DEL(rfd2obj);
    PyMem_DEL(wfd2obj);
    PyMem_DEL(efd2obj);
#endif /* SELECT_USES_HEAP */
    return ret;
}

#if defined(HAVE_POLL) && !defined(HAVE_BROKEN_POLL)
/*
 * poll() support
 */

typedef struct {
    PyObject_HEAD
    PyObject *dict;
    int ufd_uptodate;
    int ufd_len;
    struct pollfd *ufds;
    int poll_running;
} pollObject;

static PyTypeObject poll_Type;

/* Update the malloc'ed array of pollfds to match the dictionary
   contained within a pollObject.  Return 1 on success, 0 on an error.
*/

static int
update_ufd_array(pollObject *self)
{
    Py_ssize_t i, pos;
    PyObject *key, *value;
    struct pollfd *old_ufds = self->ufds;

    self->ufd_len = PyDict_Size(self->dict);
    PyMem_RESIZE(self->ufds, struct pollfd, self->ufd_len);
    if (self->ufds == NULL) {
        self->ufds = old_ufds;
        PyErr_NoMemory();
        return 0;
    }

    i = pos = 0;
    while (PyDict_Next(self->dict, &pos, &key, &value)) {
        assert(i < self->ufd_len);
        /* Never overflow */
        self->ufds[i].fd = (int)PyInt_AsLong(key);
        self->ufds[i].events = (short)(unsigned short)PyInt_AsLong(value);
        i++;
    }
    assert(i == self->ufd_len);
    self->ufd_uptodate = 1;
    return 1;
}

static int
ushort_converter(PyObject *obj, void *ptr)
{
    unsigned long uval;

    uval = PyLong_AsUnsignedLong(obj);
    if (uval == (unsigned long)-1 && PyErr_Occurred())
        return 0;
    if (uval > USHRT_MAX) {
        PyErr_SetString(PyExc_OverflowError,
                        "Python int too large for C unsigned short");
        return 0;
    }

    *(unsigned short *)ptr = Py_SAFE_DOWNCAST(uval, unsigned long, unsigned short);
    return 1;
}

PyDoc_STRVAR(poll_register_doc,
"register(fd [, eventmask] ) -> None\n\n\
Register a file descriptor with the polling object.\n\
fd -- either an integer, or an object with a fileno() method returning an\n\
      int.\n\
events -- an optional bitmask describing the type of events to check for");

static PyObject *
poll_register(pollObject *self, PyObject *args)
{
    PyObject *o, *key, *value;
    int fd;
    unsigned short events = POLLIN | POLLPRI | POLLOUT;
    int err;

    if (!PyArg_ParseTuple(args, "O|O&:register", &o, ushort_converter, &events))
        return NULL;

    fd = PyObject_AsFileDescriptor(o);
    if (fd == -1) return NULL;

    /* Add entry to the internal dictionary: the key is the
       file descriptor, and the value is the event mask. */
    key = PyInt_FromLong(fd);
    if (key == NULL)
        return NULL;
    value = PyInt_FromLong(events);
    if (value == NULL) {
        Py_DECREF(key);
        return NULL;
    }
    err = PyDict_SetItem(self->dict, key, value);
    Py_DECREF(key);
    Py_DECREF(value);
    if (err < 0)
        return NULL;

    self->ufd_uptodate = 0;

    Py_INCREF(Py_None);
    return Py_None;
}

PyDoc_STRVAR(poll_modify_doc,
"modify(fd, eventmask) -> None\n\n\
Modify an already registered file descriptor.\n\
fd -- either an integer, or an object with a fileno() method returning an\n\
      int.\n\
events -- an optional bitmask describing the type of events to check for");

static PyObject *
poll_modify(pollObject *self, PyObject *args)
{
    PyObject *o, *key, *value;
    int fd;
    unsigned short events;
    int err;

    if (!PyArg_ParseTuple(args, "OO&:modify", &o, ushort_converter, &events))
        return NULL;

    fd = PyObject_AsFileDescriptor(o);
    if (fd == -1) return NULL;

    /* Modify registered fd */
    key = PyInt_FromLong(fd);
    if (key == NULL)
        return NULL;
    if (PyDict_GetItem(self->dict, key) == NULL) {
        errno = ENOENT;
        PyErr_SetFromErrno(PyExc_IOError);
        return NULL;
    }
    value = PyInt_FromLong(events);
    if (value == NULL) {
        Py_DECREF(key);
        return NULL;
    }
    err = PyDict_SetItem(self->dict, key, value);
    Py_DECREF(key);
    Py_DECREF(value);
    if (err < 0)
        return NULL;

    self->ufd_uptodate = 0;

    Py_INCREF(Py_None);
    return Py_None;
}


PyDoc_STRVAR(poll_unregister_doc,
"unregister(fd) -> None\n\n\
Remove a file descriptor being tracked by the polling object.");

static PyObject *
poll_unregister(pollObject *self, PyObject *o)
{
    PyObject *key;
    int fd;

    fd = PyObject_AsFileDescriptor( o );
    if (fd == -1)
        return NULL;

    /* Check whether the fd is already in the array */
    key = PyInt_FromLong(fd);
    if (key == NULL)
        return NULL;

    if (PyDict_DelItem(self->dict, key) == -1) {
        Py_DECREF(key);
        /* This will simply raise the KeyError set by PyDict_DelItem
           if the file descriptor isn't registered. */
        return NULL;
    }

    Py_DECREF(key);
    self->ufd_uptodate = 0;

    Py_INCREF(Py_None);
    return Py_None;
}

PyDoc_STRVAR(poll_poll_doc,
"poll( [timeout] ) -> list of (fd, event) 2-tuples\n\n\
Polls the set of registered file descriptors, returning a list containing \n\
any descriptors that have events or errors to report.");

static PyObject *
poll_poll(pollObject *self, PyObject *args)
{
    PyObject *result_list = NULL, *tout = NULL;
    int timeout = 0, poll_result, i, j;
    PyObject *value = NULL, *num = NULL;

    if (!PyArg_UnpackTuple(args, "poll", 0, 1, &tout)) {
        return NULL;
    }

    /* Check values for timeout */
    if (tout == NULL || tout == Py_None)
        timeout = -1;
    else if (!PyNumber_Check(tout)) {
        PyErr_SetString(PyExc_TypeError,
                        "timeout must be an integer or None");
        return NULL;
    }
    else {
        tout = PyNumber_Int(tout);
        if (!tout)
            return NULL;
        timeout = _PyInt_AsInt(tout);
        Py_DECREF(tout);
        if (timeout == -1 && PyErr_Occurred())
            return NULL;
    }

    /* Avoid concurrent poll() invocation, issue 8865 */
    if (self->poll_running) {
        PyErr_SetString(PyExc_RuntimeError,
                        "concurrent poll() invocation");
        return NULL;
    }

    /* Ensure the ufd array is up to date */
    if (!self->ufd_uptodate)
        if (update_ufd_array(self) == 0)
            return NULL;

    self->poll_running = 1;

    /* call poll() */
    Py_BEGIN_ALLOW_THREADS
    poll_result = poll(self->ufds, self->ufd_len, timeout);
    Py_END_ALLOW_THREADS

    self->poll_running = 0;

    if (poll_result < 0) {
        PyErr_SetFromErrno(SelectError);
        return NULL;
    }

    /* build the result list */

    result_list = PyList_New(poll_result);
    if (!result_list)
        return NULL;
    else {
        for (i = 0, j = 0; j < poll_result; j++) {
            /* skip to the next fired descriptor */
            while (!self->ufds[i].revents) {
                i++;
            }
            /* if we hit a NULL return, set value to NULL
               and break out of loop; code at end will
               clean up result_list */
            value = PyTuple_New(2);
            if (value == NULL)
                goto error;
            num = PyInt_FromLong(self->ufds[i].fd);
            if (num == NULL) {
                Py_DECREF(value);
                goto error;
            }
            PyTuple_SET_ITEM(value, 0, num);

            /* The &0xffff is a workaround for AIX.  'revents'
               is a 16-bit short, and IBM assigned POLLNVAL
               to be 0x8000, so the conversion to int results
               in a negative number. See SF bug #923315. */
            num = PyInt_FromLong(self->ufds[i].revents & 0xffff);
            if (num == NULL) {
                Py_DECREF(value);
                goto error;
            }
            PyTuple_SET_ITEM(value, 1, num);
            if ((PyList_SetItem(result_list, j, value)) == -1) {
                Py_DECREF(value);
                goto error;
            }
            i++;
        }
    }
    return result_list;

  error:
    Py_DECREF(result_list);
    return NULL;
}

static PyMethodDef poll_methods[] = {
    {"register",        (PyCFunction)poll_register,
     METH_VARARGS,  poll_register_doc},
    {"modify",          (PyCFunction)poll_modify,
     METH_VARARGS,  poll_modify_doc},
    {"unregister",      (PyCFunction)poll_unregister,
     METH_O,        poll_unregister_doc},
    {"poll",            (PyCFunction)poll_poll,
     METH_VARARGS,  poll_poll_doc},
    {NULL,              NULL}           /* sentinel */
};

static pollObject *
newPollObject(void)
{
    pollObject *self;
    self = PyObject_New(pollObject, &poll_Type);
    if (self == NULL)
        return NULL;
    /* ufd_uptodate is a Boolean, denoting whether the
       array pointed to by ufds matches the contents of the dictionary. */
    self->ufd_uptodate = 0;
    self->ufds = NULL;
    self->poll_running = 0;
    self->dict = PyDict_New();
    if (self->dict == NULL) {
        Py_DECREF(self);
        return NULL;
    }
    return self;
}

static void
poll_dealloc(pollObject *self)
{
    if (self->ufds != NULL)
        PyMem_DEL(self->ufds);
    Py_XDECREF(self->dict);
    PyObject_Del(self);
}

static PyObject *
poll_getattr(pollObject *self, char *name)
{
    return Py_FindMethod(poll_methods, (PyObject *)self, name);
}

static PyTypeObject poll_Type = {
    /* The ob_type field must be initialized in the module init function
     * to be portable to Windows without using C++. */
    PyVarObject_HEAD_INIT(NULL, 0)
    "select.poll",              /*tp_name*/
    sizeof(pollObject),         /*tp_basicsize*/
    0,                          /*tp_itemsize*/
    /* methods */
    (destructor)poll_dealloc, /*tp_dealloc*/
    0,                          /*tp_print*/
    (getattrfunc)poll_getattr, /*tp_getattr*/
    0,                      /*tp_setattr*/
    0,                          /*tp_compare*/
    0,                          /*tp_repr*/
    0,                          /*tp_as_number*/
    0,                          /*tp_as_sequence*/
    0,                          /*tp_as_mapping*/
    0,                          /*tp_hash*/
};

PyDoc_STRVAR(poll_doc,
"Returns a polling object, which supports registering and\n\
unregistering file descriptors, and then polling them for I/O events.");

static PyObject *
select_poll(PyObject *self, PyObject *unused)
{
    return (PyObject *)newPollObject();
}

#ifdef __APPLE__
/*
 * On some systems poll() sets errno on invalid file descriptors. We test
 * for this at runtime because this bug may be fixed or introduced between
 * OS releases.
 */
static int select_have_broken_poll(void)
{
    int poll_test;
    int filedes[2];

    struct pollfd poll_struct = { 0, POLLIN|POLLPRI|POLLOUT, 0 };

    /* Create a file descriptor to make invalid */
    if (pipe(filedes) < 0) {
        return 1;
    }
    poll_struct.fd = filedes[0];
    close(filedes[0]);
    close(filedes[1]);
    poll_test = poll(&poll_struct, 1, 0);
    if (poll_test < 0) {
        return 1;
    } else if (poll_test == 0 && poll_struct.revents != POLLNVAL) {
        return 1;
    }
    return 0;
}
#endif /* __APPLE__ */

#endif /* HAVE_POLL */

#ifdef HAVE_EPOLL
/* **************************************************************************
 *                      epoll interface for Linux 2.6
 *
 * Written by Christian Heimes
 * Inspired by Twisted's _epoll.pyx and select.poll()
 */

#ifdef HAVE_SYS_EPOLL_H
#include <sys/epoll.h>
#endif

typedef struct {
    PyObject_HEAD
    SOCKET epfd;                        /* epoll control file descriptor */
} pyEpoll_Object;

static PyTypeObject pyEpoll_Type;
#define pyepoll_CHECK(op) (PyObject_TypeCheck((op), &pyEpoll_Type))

static PyObject *
pyepoll_err_closed(void)
{
    PyErr_SetString(PyExc_ValueError, "I/O operation on closed epoll fd");
    return NULL;
}

static int
pyepoll_internal_close(pyEpoll_Object *self)
{
    int save_errno = 0;
    if (self->epfd >= 0) {
        int epfd = self->epfd;
        self->epfd = -1;
        Py_BEGIN_ALLOW_THREADS
        if (close(epfd) < 0)
            save_errno = errno;
        Py_END_ALLOW_THREADS
    }
    return save_errno;
}

static PyObject *
newPyEpoll_Object(PyTypeObject *type, int sizehint, SOCKET fd)
{
    pyEpoll_Object *self;

    if (sizehint == -1) {
        sizehint = FD_SETSIZE-1;
    }
    else if (sizehint < 1) {
        PyErr_Format(PyExc_ValueError,
                     "sizehint must be greater zero, got %d",
                     sizehint);
        return NULL;
    }

    assert(type != NULL && type->tp_alloc != NULL);
    self = (pyEpoll_Object *) type->tp_alloc(type, 0);
    if (self == NULL)
        return NULL;

    if (fd == -1) {
        Py_BEGIN_ALLOW_THREADS
        self->epfd = epoll_create(sizehint);
        Py_END_ALLOW_THREADS
    }
    else {
        self->epfd = fd;
    }
    if (self->epfd < 0) {
        Py_DECREF(self);
        PyErr_SetFromErrno(PyExc_IOError);
        return NULL;
    }
    return (PyObject *)self;
}


static PyObject *
pyepoll_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
{
    int sizehint = -1;
    static char *kwlist[] = {"sizehint", NULL};

    if (!PyArg_ParseTupleAndKeywords(args, kwds, "|i:epoll", kwlist,
                                     &sizehint))
        return NULL;

    return newPyEpoll_Object(type, sizehint, -1);
}


static void
pyepoll_dealloc(pyEpoll_Object *self)
{
    (void)pyepoll_internal_close(self);
    Py_TYPE(self)->tp_free(self);
}

static PyObject*
pyepoll_close(pyEpoll_Object *self)
{
    errno = pyepoll_internal_close(self);
    if (errno < 0) {
        PyErr_SetFromErrno(PyExc_IOError);
        return NULL;
    }
    Py_RETURN_NONE;
}

PyDoc_STRVAR(pyepoll_close_doc,
"close() -> None\n\
\n\
Close the epoll control file descriptor. Further operations on the epoll\n\
object will raise an exception.");

static PyObject*
pyepoll_get_closed(pyEpoll_Object *self)
{
    if (self->epfd < 0)
        Py_RETURN_TRUE;
    else
        Py_RETURN_FALSE;
}

static PyObject*
pyepoll_fileno(pyEpoll_Object *self)
{
    if (self->epfd < 0)
        return pyepoll_err_closed();
    return PyInt_FromLong(self->epfd);
}

PyDoc_STRVAR(pyepoll_fileno_doc,
"fileno() -> int\n\
\n\
Return the epoll control file descriptor.");

static PyObject*
pyepoll_fromfd(PyObject *cls, PyObject *args)
{
    SOCKET fd;

    if (!PyArg_ParseTuple(args, "i:fromfd", &fd))
        return NULL;

    return newPyEpoll_Object((PyTypeObject*)cls, -1, fd);
}

PyDoc_STRVAR(pyepoll_fromfd_doc,
"fromfd(fd) -> epoll\n\
\n\
Create an epoll object from a given control fd.");

static PyObject *
pyepoll_internal_ctl(int epfd, int op, PyObject *pfd, unsigned int events)
{
    struct epoll_event ev;
    int result;
    int fd;

    if (epfd < 0)
        return pyepoll_err_closed();

    fd = PyObject_AsFileDescriptor(pfd);
    if (fd == -1) {
        return NULL;
    }

    switch(op) {
        case EPOLL_CTL_ADD:
        case EPOLL_CTL_MOD:
        ev.events = events;
        ev.data.fd = fd;
        Py_BEGIN_ALLOW_THREADS
        result = epoll_ctl(epfd, op, fd, &ev);
        Py_END_ALLOW_THREADS
        break;
        case EPOLL_CTL_DEL:
        /* In kernel versions before 2.6.9, the EPOLL_CTL_DEL
         * operation required a non-NULL pointer in event, even
         * though this argument is ignored. */
        Py_BEGIN_ALLOW_THREADS
        result = epoll_ctl(epfd, op, fd, &ev);
        if (errno == EBADF) {
            /* fd already closed */
            result = 0;
            errno = 0;
        }
        Py_END_ALLOW_THREADS
        break;
        default:
        result = -1;
        errno = EINVAL;
    }

    if (result < 0) {
        PyErr_SetFromErrno(PyExc_IOError);
        return NULL;
    }
    Py_RETURN_NONE;
}

static PyObject *
pyepoll_register(pyEpoll_Object *self, PyObject *args, PyObject *kwds)
{
    PyObject *pfd;
    unsigned int events = EPOLLIN | EPOLLOUT | EPOLLPRI;
    static char *kwlist[] = {"fd", "eventmask", NULL};

    if (!PyArg_ParseTupleAndKeywords(args, kwds, "O|I:register", kwlist,
                                     &pfd, &events)) {
        return NULL;
    }

    return pyepoll_internal_ctl(self->epfd, EPOLL_CTL_ADD, pfd, events);
}

PyDoc_STRVAR(pyepoll_register_doc,
"register(fd[, eventmask]) -> None\n\
\n\
Registers a new fd or raises an IOError if the fd is already registered.\n\
fd is the target file descriptor of the operation.\n\
events is a bit set composed of the various EPOLL constants; the default\n\
is EPOLL_IN | EPOLL_OUT | EPOLL_PRI.\n\
\n\
The epoll interface supports all file descriptors that support poll.");

static PyObject *
pyepoll_modify(pyEpoll_Object *self, PyObject *args, PyObject *kwds)
{
    PyObject *pfd;
    unsigned int events;
    static char *kwlist[] = {"fd", "eventmask", NULL};

    if (!PyArg_ParseTupleAndKeywords(args, kwds, "OI:modify", kwlist,
                                     &pfd, &events)) {
        return NULL;
    }

    return pyepoll_internal_ctl(self->epfd, EPOLL_CTL_MOD, pfd, events);
}

PyDoc_STRVAR(pyepoll_modify_doc,
"modify(fd, eventmask) -> None\n\
\n\
fd is the target file descriptor of the operation\n\
events is a bit set composed of the various EPOLL constants");

static PyObject *
pyepoll_unregister(pyEpoll_Object *self, PyObject *args, PyObject *kwds)
{
    PyObject *pfd;
    static char *kwlist[] = {"fd", NULL};

    if (!PyArg_ParseTupleAndKeywords(args, kwds, "O:unregister", kwlist,
                                     &pfd)) {
        return NULL;
    }

    return pyepoll_internal_ctl(self->epfd, EPOLL_CTL_DEL, pfd, 0);
}

PyDoc_STRVAR(pyepoll_unregister_doc,
"unregister(fd) -> None\n\
\n\
fd is the target file descriptor of the operation.");

static PyObject *
pyepoll_poll(pyEpoll_Object *self, PyObject *args, PyObject *kwds)
{
    double dtimeout = -1.;
    int timeout;
    int maxevents = -1;
    int nfds, i;
    PyObject *elist = NULL, *etuple = NULL;
    struct epoll_event *evs = NULL;
    static char *kwlist[] = {"timeout", "maxevents", NULL};

    if (self->epfd < 0)
        return pyepoll_err_closed();

    if (!PyArg_ParseTupleAndKeywords(args, kwds, "|di:poll", kwlist,
                                     &dtimeout, &maxevents)) {
        return NULL;
    }

    if (dtimeout < 0) {
        timeout = -1;
    }
    else if (dtimeout * 1000.0 > INT_MAX) {
        PyErr_SetString(PyExc_OverflowError,
                        "timeout is too large");
        return NULL;
    }
    else {
        timeout = (int)(dtimeout * 1000.0);
    }

    if (maxevents == -1) {
        maxevents = FD_SETSIZE-1;
    }
    else if (maxevents < 1) {
        PyErr_Format(PyExc_ValueError,
                     "maxevents must be greater than 0, got %d",
                     maxevents);
        return NULL;
    }

    evs = PyMem_New(struct epoll_event, maxevents);
    if (evs == NULL) {
        Py_DECREF(self);
        PyErr_NoMemory();
        return NULL;
    }

    Py_BEGIN_ALLOW_THREADS
    nfds = epoll_wait(self->epfd, evs, maxevents, timeout);
    Py_END_ALLOW_THREADS
    if (nfds < 0) {
        PyErr_SetFromErrno(PyExc_IOError);
        goto error;
    }

    elist = PyList_New(nfds);
    if (elist == NULL) {
        goto error;
    }

    for (i = 0; i < nfds; i++) {
        etuple = Py_BuildValue("iI", evs[i].data.fd, evs[i].events);
        if (etuple == NULL) {
            Py_CLEAR(elist);
            goto error;
        }
        PyList_SET_ITEM(elist, i, etuple);
    }

    error:
    PyMem_Free(evs);
    return elist;
}

PyDoc_STRVAR(pyepoll_poll_doc,
"poll([timeout=-1[, maxevents=-1]]) -> [(fd, events), (...)]\n\
\n\
Wait for events on the epoll file descriptor for a maximum time of timeout\n\
in seconds (as float). -1 makes poll wait indefinitely.\n\
Up to maxevents are returned to the caller.");

static PyMethodDef pyepoll_methods[] = {
    {"fromfd",          (PyCFunction)pyepoll_fromfd,
     METH_VARARGS | METH_CLASS, pyepoll_fromfd_doc},
    {"close",           (PyCFunction)pyepoll_close,     METH_NOARGS,
     pyepoll_close_doc},
    {"fileno",          (PyCFunction)pyepoll_fileno,    METH_NOARGS,
     pyepoll_fileno_doc},
    {"modify",          (PyCFunction)pyepoll_modify,
     METH_VARARGS | METH_KEYWORDS,      pyepoll_modify_doc},
    {"register",        (PyCFunction)pyepoll_register,
     METH_VARARGS | METH_KEYWORDS,      pyepoll_register_doc},
    {"unregister",      (PyCFunction)pyepoll_unregister,
     METH_VARARGS | METH_KEYWORDS,      pyepoll_unregister_doc},
    {"poll",            (PyCFunction)pyepoll_poll,
     METH_VARARGS | METH_KEYWORDS,      pyepoll_poll_doc},
    {NULL,      NULL},
};

static PyGetSetDef pyepoll_getsetlist[] = {
    {"closed", (getter)pyepoll_get_closed, NULL,
     "True if the epoll handler is closed"},
    {0},
};

PyDoc_STRVAR(pyepoll_doc,
"select.epoll([sizehint=-1])\n\
\n\
Returns an epolling object\n\
\n\
sizehint must be a positive integer or -1 for the default size. The\n\
sizehint is used to optimize internal data structures. It doesn't limit\n\
the maximum number of monitored events.");

static PyTypeObject pyEpoll_Type = {
    PyVarObject_HEAD_INIT(NULL, 0)
    "select.epoll",                                     /* tp_name */
    sizeof(pyEpoll_Object),                             /* tp_basicsize */
    0,                                                  /* tp_itemsize */
    (destructor)pyepoll_dealloc,                        /* tp_dealloc */
    0,                                                  /* tp_print */
    0,                                                  /* tp_getattr */
    0,                                                  /* tp_setattr */
    0,                                                  /* tp_compare */
    0,                                                  /* tp_repr */
    0,                                                  /* tp_as_number */
    0,                                                  /* tp_as_sequence */
    0,                                                  /* tp_as_mapping */
    0,                                                  /* tp_hash */
    0,                                                  /* tp_call */
    0,                                                  /* tp_str */
    PyObject_GenericGetAttr,                            /* tp_getattro */
    0,                                                  /* tp_setattro */
    0,                                                  /* tp_as_buffer */
    Py_TPFLAGS_DEFAULT,                                 /* tp_flags */
    pyepoll_doc,                                        /* tp_doc */
    0,                                                  /* tp_traverse */
    0,                                                  /* tp_clear */
    0,                                                  /* tp_richcompare */
    0,                                                  /* tp_weaklistoffset */
    0,                                                  /* tp_iter */
    0,                                                  /* tp_iternext */
    pyepoll_methods,                                    /* tp_methods */
    0,                                                  /* tp_members */
    pyepoll_getsetlist,                                 /* tp_getset */
    0,                                                  /* tp_base */
    0,                                                  /* tp_dict */
    0,                                                  /* tp_descr_get */
    0,                                                  /* tp_descr_set */
    0,                                                  /* tp_dictoffset */
    0,                                                  /* tp_init */
    0,                                                  /* tp_alloc */
    pyepoll_new,                                        /* tp_new */
    0,                                                  /* tp_free */
};

#endif /* HAVE_EPOLL */

#ifdef HAVE_KQUEUE
/* **************************************************************************
 *                      kqueue interface for BSD
 *
 * Copyright (c) 2000 Doug White, 2006 James Knight, 2007 Christian Heimes
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifdef HAVE_SYS_EVENT_H
#include <sys/event.h>
#endif

PyDoc_STRVAR(kqueue_event_doc,
"kevent(ident, filter=KQ_FILTER_READ, flags=KQ_EV_ADD, fflags=0, data=0, udata=0)\n\
\n\
This object is the equivalent of the struct kevent for the C API.\n\
\n\
See the kqueue manpage for more detailed information about the meaning\n\
of the arguments.\n\
\n\
One minor note: while you might hope that udata could store a\n\
reference to a python object, it cannot, because it is impossible to\n\
keep a proper reference count of the object once it's passed into the\n\
kernel. Therefore, I have restricted it to only storing an integer.  I\n\
recommend ignoring it and simply using the 'ident' field to key off\n\
of. You could also set up a dictionary on the python side to store a\n\
udata->object mapping.");

typedef struct {
    PyObject_HEAD
    struct kevent e;
} kqueue_event_Object;

static PyTypeObject kqueue_event_Type;

#define kqueue_event_Check(op) (PyObject_TypeCheck((op), &kqueue_event_Type))

typedef struct {
    PyObject_HEAD
    SOCKET kqfd;                /* kqueue control fd */
} kqueue_queue_Object;

static PyTypeObject kqueue_queue_Type;

#define kqueue_queue_Check(op) (PyObject_TypeCheck((op), &kqueue_queue_Type))

#if (SIZEOF_UINTPTR_T != SIZEOF_VOID_P)
#   error uintptr_t does not match void *!
#elif (SIZEOF_UINTPTR_T == SIZEOF_LONG_LONG)
#   define T_UINTPTRT         T_ULONGLONG
#   define T_INTPTRT          T_LONGLONG
#   define PyLong_AsUintptr_t PyLong_AsUnsignedLongLong
#   define UINTPTRT_FMT_UNIT  "K"
#   define INTPTRT_FMT_UNIT   "L"
#elif (SIZEOF_UINTPTR_T == SIZEOF_LONG)
#   define T_UINTPTRT         T_ULONG
#   define T_INTPTRT          T_LONG
#   define PyLong_AsUintptr_t PyLong_AsUnsignedLong
#   define UINTPTRT_FMT_UNIT  "k"
#   define INTPTRT_FMT_UNIT   "l"
#elif (SIZEOF_UINTPTR_T == SIZEOF_INT)
#   define T_UINTPTRT         T_UINT
#   define T_INTPTRT          T_INT
#   define PyLong_AsUintptr_t PyLong_AsUnsignedLong
#   define UINTPTRT_FMT_UNIT  "I"
#   define INTPTRT_FMT_UNIT   "i"
#else
#   error uintptr_t does not match int, long, or long long!
#endif

/*
 * kevent is not standard and its members vary across BSDs.
 */
#if !defined(__OpenBSD__)
#   define IDENT_TYPE T_UINTPTRT
#   define IDENT_CAST Py_intptr_t
#   define DATA_TYPE  T_INTPTRT
#   define DATA_FMT_UNIT INTPTRT_FMT_UNIT
#   define IDENT_AsType PyLong_AsUintptr_t
#else
#   define IDENT_TYPE T_UINT
#   define IDENT_CAST int
#   define DATA_TYPE  T_INT
#   define DATA_FMT_UNIT "i"
#   define IDENT_AsType PyLong_AsUnsignedLong
#endif

/* Unfortunately, we can't store python objects in udata, because
 * kevents in the kernel can be removed without warning, which would
 * forever lose the refcount on the object stored with it.
 */

#define KQ_OFF(x) offsetof(kqueue_event_Object, x)
static struct PyMemberDef kqueue_event_members[] = {
    {"ident",           IDENT_TYPE,     KQ_OFF(e.ident)},
    {"filter",          T_SHORT,        KQ_OFF(e.filter)},
    {"flags",           T_USHORT,       KQ_OFF(e.flags)},
    {"fflags",          T_UINT,         KQ_OFF(e.fflags)},
    {"data",            DATA_TYPE,      KQ_OFF(e.data)},
    {"udata",           T_UINTPTRT,     KQ_OFF(e.udata)},
    {NULL} /* Sentinel */
};
#undef KQ_OFF

static PyObject *

kqueue_event_repr(kqueue_event_Object *s)
{
    char buf[1024];
    PyOS_snprintf(
        buf, sizeof(buf),
        "<select.kevent ident=%zu filter=%d flags=0x%x fflags=0x%x "
        "data=0x%zd udata=%p>",
        (size_t)(s->e.ident), s->e.filter, s->e.flags,
        s->e.fflags, (Py_ssize_t)(s->e.data), s->e.udata);
    return PyString_FromString(buf);
}

static int
kqueue_event_init(kqueue_event_Object *self, PyObject *args, PyObject *kwds)
{
    PyObject *pfd;
    static char *kwlist[] = {"ident", "filter", "flags", "fflags",
                             "data", "udata", NULL};
    static char *fmt = "O|hHI" DATA_FMT_UNIT UINTPTRT_FMT_UNIT ":kevent";

    EV_SET(&(self->e), 0, EVFILT_READ, EV_ADD, 0, 0, 0); /* defaults */

    if (!PyArg_ParseTupleAndKeywords(args, kwds, fmt, kwlist,
        &pfd, &(self->e.filter), &(self->e.flags),
        &(self->e.fflags), &(self->e.data), &(self->e.udata))) {
        return -1;
    }

    if (PyLong_Check(pfd)
#if IDENT_TYPE == T_UINT
  && PyLong_AsUnsignedLong(pfd) <= UINT_MAX
#endif
    ) {
        self->e.ident = IDENT_AsType(pfd);
    }
    else {
        self->e.ident = PyObject_AsFileDescriptor(pfd);
    }
    if (PyErr_Occurred()) {
        return -1;
    }
    return 0;
}

static PyObject *
kqueue_event_richcompare(kqueue_event_Object *s, kqueue_event_Object *o,
                         int op)
{
    Py_intptr_t result = 0;

    if (!kqueue_event_Check(o)) {
        if (op == Py_EQ || op == Py_NE) {
            PyObject *res = op == Py_EQ ? Py_False : Py_True;
            Py_INCREF(res);
            return res;
        }
        PyErr_Format(PyExc_TypeError,
            "can't compare %.200s to %.200s",
            Py_TYPE(s)->tp_name, Py_TYPE(o)->tp_name);
        return NULL;
    }
    if (((result = (IDENT_CAST)(s->e.ident - o->e.ident)) == 0) &&
        ((result = s->e.filter - o->e.filter) == 0) &&
        ((result = s->e.flags - o->e.flags) == 0) &&
        ((result = (int)(s->e.fflags - o->e.fflags)) == 0) &&
        ((result = s->e.data - o->e.data) == 0) &&
        ((result = s->e.udata - o->e.udata) == 0)
       ) {
        result = 0;
    }

    switch (op) {
        case Py_EQ:
        result = (result == 0);
        break;
        case Py_NE:
        result = (result != 0);
        break;
        case Py_LE:
        result = (result <= 0);
        break;
        case Py_GE:
        result = (result >= 0);
        break;
        case Py_LT:
        result = (result < 0);
        break;
        case Py_GT:
        result = (result > 0);
        break;
    }
    return PyBool_FromLong((long)result);
}

static PyTypeObject kqueue_event_Type = {
    PyVarObject_HEAD_INIT(NULL, 0)
    "select.kevent",                                    /* tp_name */
    sizeof(kqueue_event_Object),                        /* tp_basicsize */
    0,                                                  /* tp_itemsize */
    0,                                                  /* tp_dealloc */
    0,                                                  /* tp_print */
    0,                                                  /* tp_getattr */
    0,                                                  /* tp_setattr */
    0,                                                  /* tp_compare */
    (reprfunc)kqueue_event_repr,                        /* tp_repr */
    0,                                                  /* tp_as_number */
    0,                                                  /* tp_as_sequence */
    0,                                                  /* tp_as_mapping */
    0,                                                  /* tp_hash */
    0,                                                  /* tp_call */
    0,                                                  /* tp_str */
    0,                                                  /* tp_getattro */
    0,                                                  /* tp_setattro */
    0,                                                  /* tp_as_buffer */
    Py_TPFLAGS_DEFAULT,                                 /* tp_flags */
    kqueue_event_doc,                                   /* tp_doc */
    0,                                                  /* tp_traverse */
    0,                                                  /* tp_clear */
    (richcmpfunc)kqueue_event_richcompare,              /* tp_richcompare */
    0,                                                  /* tp_weaklistoffset */
    0,                                                  /* tp_iter */
    0,                                                  /* tp_iternext */
    0,                                                  /* tp_methods */
    kqueue_event_members,                               /* tp_members */
    0,                                                  /* tp_getset */
    0,                                                  /* tp_base */
    0,                                                  /* tp_dict */
    0,                                                  /* tp_descr_get */
    0,                                                  /* tp_descr_set */
    0,                                                  /* tp_dictoffset */
    (initproc)kqueue_event_init,                        /* tp_init */
    0,                                                  /* tp_alloc */
    0,                                                  /* tp_new */
    0,                                                  /* tp_free */
};

static PyObject *
kqueue_queue_err_closed(void)
{
    PyErr_SetString(PyExc_ValueError, "I/O operation on closed kqueue fd");
    return NULL;
}

static int
kqueue_queue_internal_close(kqueue_queue_Object *self)
{
    int save_errno = 0;
    if (self->kqfd >= 0) {
        int kqfd = self->kqfd;
        self->kqfd = -1;
        Py_BEGIN_ALLOW_THREADS
        if (close(kqfd) < 0)
            save_errno = errno;
        Py_END_ALLOW_THREADS
    }
    return save_errno;
}

static PyObject *
newKqueue_Object(PyTypeObject *type, SOCKET fd)
{
    kqueue_queue_Object *self;
    assert(type != NULL && type->tp_alloc != NULL);
    self = (kqueue_queue_Object *) type->tp_alloc(type, 0);
    if (self == NULL) {
        return NULL;
    }

    if (fd == -1) {
        Py_BEGIN_ALLOW_THREADS
        self->kqfd = kqueue();
        Py_END_ALLOW_THREADS
    }
    else {
        self->kqfd = fd;
    }
    if (self->kqfd < 0) {
        Py_DECREF(self);
        PyErr_SetFromErrno(PyExc_IOError);
        return NULL;
    }
    return (PyObject *)self;
}

static PyObject *
kqueue_queue_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
{

    if ((args != NULL && PyObject_Size(args)) ||
                    (kwds != NULL && PyObject_Size(kwds))) {
        PyErr_SetString(PyExc_ValueError,
                        "select.kqueue doesn't accept arguments");
        return NULL;
    }

    return newKqueue_Object(type, -1);
}

static void
kqueue_queue_dealloc(kqueue_queue_Object *self)
{
    kqueue_queue_internal_close(self);
    Py_TYPE(self)->tp_free(self);
}

static PyObject*
kqueue_queue_close(kqueue_queue_Object *self)
{
    errno = kqueue_queue_internal_close(self);
    if (errno < 0) {
        PyErr_SetFromErrno(PyExc_IOError);
        return NULL;
    }
    Py_RETURN_NONE;
}

PyDoc_STRVAR(kqueue_queue_close_doc,
"close() -> None\n\
\n\
Close the kqueue control file descriptor. Further operations on the kqueue\n\
object will raise an exception.");

static PyObject*
kqueue_queue_get_closed(kqueue_queue_Object *self)
{
    if (self->kqfd < 0)
        Py_RETURN_TRUE;
    else
        Py_RETURN_FALSE;
}

static PyObject*
kqueue_queue_fileno(kqueue_queue_Object *self)
{
    if (self->kqfd < 0)
        return kqueue_queue_err_closed();
    return PyInt_FromLong(self->kqfd);
}

PyDoc_STRVAR(kqueue_queue_fileno_doc,
"fileno() -> int\n\
\n\
Return the kqueue control file descriptor.");

static PyObject*
kqueue_queue_fromfd(PyObject *cls, PyObject *args)
{
    SOCKET fd;

    if (!PyArg_ParseTuple(args, "i:fromfd", &fd))
        return NULL;

    return newKqueue_Object((PyTypeObject*)cls, fd);
}

PyDoc_STRVAR(kqueue_queue_fromfd_doc,
"fromfd(fd) -> kqueue\n\
\n\
Create a kqueue object from a given control fd.");

static PyObject *
kqueue_queue_control(kqueue_queue_Object *self, PyObject *args)
{
    int nevents = 0;
    int gotevents = 0;
    int nchanges = 0;
    int i = 0;
    PyObject *otimeout = NULL;
    PyObject *ch = NULL;
    PyObject *it = NULL, *ei = NULL;
    PyObject *result = NULL;
    struct kevent *evl = NULL;
    struct kevent *chl = NULL;
    struct timespec timeoutspec;
    struct timespec *ptimeoutspec;

    if (self->kqfd < 0)
        return kqueue_queue_err_closed();

    if (!PyArg_ParseTuple(args, "Oi|O:control", &ch, &nevents, &otimeout))
        return NULL;

    if (nevents < 0) {
        PyErr_Format(PyExc_ValueError,
            "Length of eventlist must be 0 or positive, got %d",
            nevents);
        return NULL;
    }

    if (otimeout == Py_None || otimeout == NULL) {
        ptimeoutspec = NULL;
    }
    else if (PyNumber_Check(otimeout)) {
        double timeout;
        long seconds;

        timeout = PyFloat_AsDouble(otimeout);
        if (timeout == -1 && PyErr_Occurred())
            return NULL;
        if (timeout > (double)LONG_MAX) {
            PyErr_SetString(PyExc_OverflowError,
                            "timeout period too long");
            return NULL;
        }
        if (timeout < 0) {
            PyErr_SetString(PyExc_ValueError,
                            "timeout must be positive or None");
            return NULL;
        }

        seconds = (long)timeout;
        timeout = timeout - (double)seconds;
        timeoutspec.tv_sec = seconds;
        timeoutspec.tv_nsec = (long)(timeout * 1E9);
        ptimeoutspec = &timeoutspec;
    }
    else {
        PyErr_Format(PyExc_TypeError,
            "timeout argument must be an number "
            "or None, got %.200s",
            Py_TYPE(otimeout)->tp_name);
        return NULL;
    }

    if (ch != NULL && ch != Py_None) {
        it = PyObject_GetIter(ch);
        if (it == NULL) {
            PyErr_SetString(PyExc_TypeError,
                            "changelist is not iterable");
            return NULL;
        }
        nchanges = PyObject_Size(ch);
        if (nchanges < 0) {
            goto error;
        }

        chl = PyMem_New(struct kevent, nchanges);
        if (chl == NULL) {
            PyErr_NoMemory();
            goto error;
        }
        i = 0;
        while ((ei = PyIter_Next(it)) != NULL) {
            if (!kqueue_event_Check(ei)) {
                Py_DECREF(ei);
                PyErr_SetString(PyExc_TypeError,
                    "changelist must be an iterable of "
                    "select.kevent objects");
                goto error;
            } else {
                chl[i++] = ((kqueue_event_Object *)ei)->e;
            }
            Py_DECREF(ei);
        }
    }
    Py_CLEAR(it);

    /* event list */
    if (nevents) {
        evl = PyMem_New(struct kevent, nevents);
        if (evl == NULL) {
            PyErr_NoMemory();
            goto error;
        }
    }

    Py_BEGIN_ALLOW_THREADS
    gotevents = kevent(self->kqfd, chl, nchanges,
                       evl, nevents, ptimeoutspec);
    Py_END_ALLOW_THREADS

    if (gotevents == -1) {
        PyErr_SetFromErrno(PyExc_OSError);
        goto error;
    }

    result = PyList_New(gotevents);
    if (result == NULL) {
        goto error;
    }

    for (i = 0; i < gotevents; i++) {
        kqueue_event_Object *ch;

        ch = PyObject_New(kqueue_event_Object, &kqueue_event_Type);
        if (ch == NULL) {
            goto error;
        }
        ch->e = evl[i];
        PyList_SET_ITEM(result, i, (PyObject *)ch);
    }
    PyMem_Free(chl);
    PyMem_Free(evl);
    return result;

    error:
    PyMem_Free(chl);
    PyMem_Free(evl);
    Py_XDECREF(result);
    Py_XDECREF(it);
    return NULL;
}

PyDoc_STRVAR(kqueue_queue_control_doc,
"control(changelist, max_events[, timeout=None]) -> eventlist\n\
\n\
Calls the kernel kevent function.\n\
- changelist must be a list of kevent objects describing the changes\n\
  to be made to the kernel's watch list or None.\n\
- max_events lets you specify the maximum number of events that the\n\
  kernel will return.\n\
- timeout is the maximum time to wait in seconds, or else None,\n\
  to wait forever. timeout accepts floats for smaller timeouts, too.");


static PyMethodDef kqueue_queue_methods[] = {
    {"fromfd",          (PyCFunction)kqueue_queue_fromfd,
     METH_VARARGS | METH_CLASS, kqueue_queue_fromfd_doc},
    {"close",           (PyCFunction)kqueue_queue_close,        METH_NOARGS,
     kqueue_queue_close_doc},
    {"fileno",          (PyCFunction)kqueue_queue_fileno,       METH_NOARGS,
     kqueue_queue_fileno_doc},
    {"control",         (PyCFunction)kqueue_queue_control,
     METH_VARARGS ,     kqueue_queue_control_doc},
    {NULL,      NULL},
};

static PyGetSetDef kqueue_queue_getsetlist[] = {
    {"closed", (getter)kqueue_queue_get_closed, NULL,
     "True if the kqueue handler is closed"},
    {0},
};

PyDoc_STRVAR(kqueue_queue_doc,
"Kqueue syscall wrapper.\n\
\n\
For example, to start watching a socket for input:\n\
>>> kq = kqueue()\n\
>>> sock = socket()\n\
>>> sock.connect((host, port))\n\
>>> kq.control([kevent(sock, KQ_FILTER_WRITE, KQ_EV_ADD)], 0)\n\
\n\
To wait one second for it to become writeable:\n\
>>> kq.control(None, 1, 1000)\n\
\n\
To stop listening:\n\
>>> kq.control([kevent(sock, KQ_FILTER_WRITE, KQ_EV_DELETE)], 0)");

static PyTypeObject kqueue_queue_Type = {
    PyVarObject_HEAD_INIT(NULL, 0)
    "select.kqueue",                                    /* tp_name */
    sizeof(kqueue_queue_Object),                        /* tp_basicsize */
    0,                                                  /* tp_itemsize */
    (destructor)kqueue_queue_dealloc,                   /* tp_dealloc */
    0,                                                  /* tp_print */
    0,                                                  /* tp_getattr */
    0,                                                  /* tp_setattr */
    0,                                                  /* tp_compare */
    0,                                                  /* tp_repr */
    0,                                                  /* tp_as_number */
    0,                                                  /* tp_as_sequence */
    0,                                                  /* tp_as_mapping */
    0,                                                  /* tp_hash */
    0,                                                  /* tp_call */
    0,                                                  /* tp_str */
    0,                                                  /* tp_getattro */
    0,                                                  /* tp_setattro */
    0,                                                  /* tp_as_buffer */
    Py_TPFLAGS_DEFAULT,                                 /* tp_flags */
    kqueue_queue_doc,                                   /* tp_doc */
    0,                                                  /* tp_traverse */
    0,                                                  /* tp_clear */
    0,                                                  /* tp_richcompare */
    0,                                                  /* tp_weaklistoffset */
    0,                                                  /* tp_iter */
    0,                                                  /* tp_iternext */
    kqueue_queue_methods,                               /* tp_methods */
    0,                                                  /* tp_members */
    kqueue_queue_getsetlist,                            /* tp_getset */
    0,                                                  /* tp_base */
    0,                                                  /* tp_dict */
    0,                                                  /* tp_descr_get */
    0,                                                  /* tp_descr_set */
    0,                                                  /* tp_dictoffset */
    0,                                                  /* tp_init */
    0,                                                  /* tp_alloc */
    kqueue_queue_new,                                   /* tp_new */
    0,                                                  /* tp_free */
};

#endif /* HAVE_KQUEUE */
/* ************************************************************************ */

PyDoc_STRVAR(select_doc,
"select(rlist, wlist, xlist[, timeout]) -> (rlist, wlist, xlist)\n\
\n\
Wait until one or more file descriptors are ready for some kind of I/O.\n\
The first three arguments are sequences of file descriptors to be waited for:\n\
rlist -- wait until ready for reading\n\
wlist -- wait until ready for writing\n\
xlist -- wait for an ``exceptional condition''\n\
If only one kind of condition is required, pass [] for the other lists.\n\
A file descriptor is either a socket or file object, or a small integer\n\
gotten from a fileno() method call on one of those.\n\
\n\
The optional 4th argument specifies a timeout in seconds; it may be\n\
a floating point number to specify fractions of seconds.  If it is absent\n\
or None, the call will never time out.\n\
\n\
The return value is a tuple of three lists corresponding to the first three\n\
arguments; each contains the subset of the corresponding file descriptors\n\
that are ready.\n\
\n\
*** IMPORTANT NOTICE ***\n\
On Windows and OpenVMS, only sockets are supported; on Unix, all file\n\
descriptors can be used.");

static PyMethodDef select_methods[] = {
    {"select",          select_select,  METH_VARARGS,   select_doc},
#if defined(HAVE_POLL) && !defined(HAVE_BROKEN_POLL)
    {"poll",            select_poll,    METH_NOARGS,    poll_doc},
#endif /* HAVE_POLL */
    {0,         0},     /* sentinel */
};

PyDoc_STRVAR(module_doc,
"This module supports asynchronous I/O on multiple file descriptors.\n\
\n\
*** IMPORTANT NOTICE ***\n\
On Windows and OpenVMS, only sockets are supported; on Unix, all file descriptors.");

PyMODINIT_FUNC
initselect(void)
{
    PyObject *m;
    m = Py_InitModule3("select", select_methods, module_doc);
    if (m == NULL)
        return;

    SelectError = PyErr_NewException("select.error", NULL, NULL);
    Py_INCREF(SelectError);
    PyModule_AddObject(m, "error", SelectError);

#ifdef PIPE_BUF
#ifdef HAVE_BROKEN_PIPE_BUF
#undef PIPE_BUF
#define PIPE_BUF 512
#endif
    PyModule_AddIntConstant(m, "PIPE_BUF", PIPE_BUF);
#endif

#if defined(HAVE_POLL) && !defined(HAVE_BROKEN_POLL)
#ifdef __APPLE__
    if (select_have_broken_poll()) {
        if (PyObject_DelAttrString(m, "poll") == -1) {
            PyErr_Clear();
        }
    } else {
#else
    {
#endif
        Py_TYPE(&poll_Type) = &PyType_Type;
        PyModule_AddIntConstant(m, "POLLIN", POLLIN);
        PyModule_AddIntConstant(m, "POLLPRI", POLLPRI);
        PyModule_AddIntConstant(m, "POLLOUT", POLLOUT);
        PyModule_AddIntConstant(m, "POLLERR", POLLERR);
        PyModule_AddIntConstant(m, "POLLHUP", POLLHUP);
        PyModule_AddIntConstant(m, "POLLNVAL", POLLNVAL);

#ifdef POLLRDNORM
        PyModule_AddIntConstant(m, "POLLRDNORM", POLLRDNORM);
#endif
#ifdef POLLRDBAND
        PyModule_AddIntConstant(m, "POLLRDBAND", POLLRDBAND);
#endif
#ifdef POLLWRNORM
        PyModule_AddIntConstant(m, "POLLWRNORM", POLLWRNORM);
#endif
#ifdef POLLWRBAND
        PyModule_AddIntConstant(m, "POLLWRBAND", POLLWRBAND);
#endif
#ifdef POLLMSG
        PyModule_AddIntConstant(m, "POLLMSG", POLLMSG);
#endif
    }
#endif /* HAVE_POLL */

#ifdef HAVE_EPOLL
    Py_TYPE(&pyEpoll_Type) = &PyType_Type;
    if (PyType_Ready(&pyEpoll_Type) < 0)
        return;

    Py_INCREF(&pyEpoll_Type);
    PyModule_AddObject(m, "epoll", (PyObject *) &pyEpoll_Type);

    PyModule_AddIntConstant(m, "EPOLLIN", EPOLLIN);
    PyModule_AddIntConstant(m, "EPOLLOUT", EPOLLOUT);
    PyModule_AddIntConstant(m, "EPOLLPRI", EPOLLPRI);
    PyModule_AddIntConstant(m, "EPOLLERR", EPOLLERR);
    PyModule_AddIntConstant(m, "EPOLLHUP", EPOLLHUP);
    PyModule_AddIntConstant(m, "EPOLLET", EPOLLET);
#ifdef EPOLLONESHOT
    /* Kernel 2.6.2+ */
    PyModule_AddIntConstant(m, "EPOLLONESHOT", EPOLLONESHOT);
#endif
    /* PyModule_AddIntConstant(m, "EPOLL_RDHUP", EPOLLRDHUP); */
    PyModule_AddIntConstant(m, "EPOLLRDNORM", EPOLLRDNORM);
    PyModule_AddIntConstant(m, "EPOLLRDBAND", EPOLLRDBAND);
    PyModule_AddIntConstant(m, "EPOLLWRNORM", EPOLLWRNORM);
    PyModule_AddIntConstant(m, "EPOLLWRBAND", EPOLLWRBAND);
    PyModule_AddIntConstant(m, "EPOLLMSG", EPOLLMSG);
#endif /* HAVE_EPOLL */

#ifdef HAVE_KQUEUE
    kqueue_event_Type.tp_new = PyType_GenericNew;
    Py_TYPE(&kqueue_event_Type) = &PyType_Type;
    if(PyType_Ready(&kqueue_event_Type) < 0)
        return;

    Py_INCREF(&kqueue_event_Type);
    PyModule_AddObject(m, "kevent", (PyObject *)&kqueue_event_Type);

    Py_TYPE(&kqueue_queue_Type) = &PyType_Type;
    if(PyType_Ready(&kqueue_queue_Type) < 0)
        return;
    Py_INCREF(&kqueue_queue_Type);
    PyModule_AddObject(m, "kqueue", (PyObject *)&kqueue_queue_Type);

    /* event filters */
    PyModule_AddIntConstant(m, "KQ_FILTER_READ", EVFILT_READ);
    PyModule_AddIntConstant(m, "KQ_FILTER_WRITE", EVFILT_WRITE);
    PyModule_AddIntConstant(m, "KQ_FILTER_AIO", EVFILT_AIO);
    PyModule_AddIntConstant(m, "KQ_FILTER_VNODE", EVFILT_VNODE);
    PyModule_AddIntConstant(m, "KQ_FILTER_PROC", EVFILT_PROC);
#ifdef EVFILT_NETDEV
    PyModule_AddIntConstant(m, "KQ_FILTER_NETDEV", EVFILT_NETDEV);
#endif
    PyModule_AddIntConstant(m, "KQ_FILTER_SIGNAL", EVFILT_SIGNAL);
    PyModule_AddIntConstant(m, "KQ_FILTER_TIMER", EVFILT_TIMER);

    /* event flags */
    PyModule_AddIntConstant(m, "KQ_EV_ADD", EV_ADD);
    PyModule_AddIntConstant(m, "KQ_EV_DELETE", EV_DELETE);
    PyModule_AddIntConstant(m, "KQ_EV_ENABLE", EV_ENABLE);
    PyModule_AddIntConstant(m, "KQ_EV_DISABLE", EV_DISABLE);
    PyModule_AddIntConstant(m, "KQ_EV_ONESHOT", EV_ONESHOT);
    PyModule_AddIntConstant(m, "KQ_EV_CLEAR", EV_CLEAR);

    PyModule_AddIntConstant(m, "KQ_EV_SYSFLAGS", EV_SYSFLAGS);
    PyModule_AddIntConstant(m, "KQ_EV_FLAG1", EV_FLAG1);

    PyModule_AddIntConstant(m, "KQ_EV_EOF", EV_EOF);
    PyModule_AddIntConstant(m, "KQ_EV_ERROR", EV_ERROR);

    /* READ WRITE filter flag */
    PyModule_AddIntConstant(m, "KQ_NOTE_LOWAT", NOTE_LOWAT);

    /* VNODE filter flags  */
    PyModule_AddIntConstant(m, "KQ_NOTE_DELETE", NOTE_DELETE);
    PyModule_AddIntConstant(m, "KQ_NOTE_WRITE", NOTE_WRITE);
    PyModule_AddIntConstant(m, "KQ_NOTE_EXTEND", NOTE_EXTEND);
    PyModule_AddIntConstant(m, "KQ_NOTE_ATTRIB", NOTE_ATTRIB);
    PyModule_AddIntConstant(m, "KQ_NOTE_LINK", NOTE_LINK);
    PyModule_AddIntConstant(m, "KQ_NOTE_RENAME", NOTE_RENAME);
    PyModule_AddIntConstant(m, "KQ_NOTE_REVOKE", NOTE_REVOKE);

    /* PROC filter flags  */
    PyModule_AddIntConstant(m, "KQ_NOTE_EXIT", NOTE_EXIT);
    PyModule_AddIntConstant(m, "KQ_NOTE_FORK", NOTE_FORK);
    PyModule_AddIntConstant(m, "KQ_NOTE_EXEC", NOTE_EXEC);
    PyModule_AddIntConstant(m, "KQ_NOTE_PCTRLMASK", NOTE_PCTRLMASK);
    PyModule_AddIntConstant(m, "KQ_NOTE_PDATAMASK", NOTE_PDATAMASK);

    PyModule_AddIntConstant(m, "KQ_NOTE_TRACK", NOTE_TRACK);
    PyModule_AddIntConstant(m, "KQ_NOTE_CHILD", NOTE_CHILD);
    PyModule_AddIntConstant(m, "KQ_NOTE_TRACKERR", NOTE_TRACKERR);

    /* NETDEV filter flags */
#ifdef EVFILT_NETDEV
    PyModule_AddIntConstant(m, "KQ_NOTE_LINKUP", NOTE_LINKUP);
    PyModule_AddIntConstant(m, "KQ_NOTE_LINKDOWN", NOTE_LINKDOWN);
    PyModule_AddIntConstant(m, "KQ_NOTE_LINKINV", NOTE_LINKINV);
#endif

#endif /* HAVE_KQUEUE */
}