/Modules/selectmodule.c

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/* 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.
*/

#if defined(HAVE_POLL_H) && !defined(_GNU_SOURCE)
#define _GNU_SOURCE
#endif

#include "Python.h"
#include <structmember.h>

#ifdef HAVE_SYS_DEVPOLL_H
#include <sys/resource.h>
#include <sys/devpoll.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#endif

#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

#ifdef MS_WINDOWS
#  define WIN32_LEAN_AND_MEAN
#  include <winsock.h>
#else
#  define SOCKET int
#endif

/* 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 max = -1;
    int index = 0;
    Py_ssize_t i;
    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)))
            goto finally;

        Py_INCREF(o);
        v = PyObject_AsFileDescriptor( o );
        if (v == -1) goto finally;

#if defined(_MSC_VER)
        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 *timeout_obj = Py_None;
    fd_set ifdset, ofdset, efdset;
    struct timeval tv, *tvp;
    int imax, omax, emax, max;
    int n;
    _PyTime_t timeout, deadline = 0;

    /* convert arguments */
    if (!PyArg_UnpackTuple(args, "select", 3, 4,
                          &ifdlist, &ofdlist, &efdlist, &timeout_obj))
        return NULL;

    if (timeout_obj == Py_None)
        tvp = (struct timeval *)NULL;
    else {
        if (_PyTime_FromSecondsObject(&timeout, timeout_obj,
                                      _PyTime_ROUND_CEILING) < 0) {
            if (PyErr_ExceptionMatches(PyExc_TypeError)) {
                PyErr_SetString(PyExc_TypeError,
                                "timeout must be a float or None");
            }
            return NULL;
        }

        if (_PyTime_AsTimeval(timeout, &tv, _PyTime_ROUND_CEILING) == -1)
            return NULL;
        if (tv.tv_sec < 0) {
            PyErr_SetString(PyExc_ValueError, "timeout must be non-negative");
            return NULL;
        }
        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;

    if (tvp)
        deadline = _PyTime_GetMonotonicClock() + timeout;

    do {
        Py_BEGIN_ALLOW_THREADS
        errno = 0;
        n = select(max, &ifdset, &ofdset, &efdset, tvp);
        Py_END_ALLOW_THREADS

        if (errno != EINTR)
            break;

        /* select() was interrupted by a signal */
        if (PyErr_CheckSignals())
            goto finally;

        if (tvp) {
            timeout = deadline - _PyTime_GetMonotonicClock();
            if (timeout < 0) {
                n = 0;
                break;
            }
            _PyTime_AsTimeval_noraise(timeout, &tv, _PyTime_ROUND_CEILING);
            /* retry select() with the recomputed timeout */
        }
    } while (1);

#ifdef MS_WINDOWS
    if (n == SOCKET_ERROR) {
        PyErr_SetExcFromWindowsErr(PyExc_OSError, WSAGetLastError());
    }
#else
    if (n < 0) {
        PyErr_SetFromErrno(PyExc_OSError);
    }
#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_XDECREF(ifdlist);
        Py_XDECREF(ofdlist);
        Py_XDECREF(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)PyLong_AsLong(key);
        self->ufds[i].events = (short)(unsigned short)PyLong_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 = PyLong_FromLong(fd);
    if (key == NULL)
        return NULL;
    value = PyLong_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 = PyLong_FromLong(fd);
    if (key == NULL)
        return NULL;
    if (PyDict_GetItem(self->dict, key) == NULL) {
        errno = ENOENT;
        PyErr_SetFromErrno(PyExc_OSError);
        Py_DECREF(key);
        return NULL;
    }
    value = PyLong_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 = PyLong_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, *timeout_obj = NULL;
    int poll_result, i, j;
    PyObject *value = NULL, *num = NULL;
    _PyTime_t timeout, ms, deadline;
    int async_err = 0;

    if (!PyArg_ParseTuple(args, "|O:poll", &timeout_obj)) {
        return NULL;
    }

    /* Check values for timeout */
    if (timeout_obj == NULL || timeout_obj == Py_None) {
        timeout = -1;
        ms = -1;
        deadline = 0;   /* initialize to prevent gcc warning */
    }
    else {
        if (_PyTime_FromMillisecondsObject(&timeout, timeout_obj,
                                           _PyTime_ROUND_CEILING) < 0) {
            if (PyErr_ExceptionMatches(PyExc_TypeError)) {
                PyErr_SetString(PyExc_TypeError,
                                "timeout must be an integer or None");
            }
            return NULL;
        }

        ms = _PyTime_AsMilliseconds(timeout, _PyTime_ROUND_CEILING);
        if (ms < INT_MIN || ms > INT_MAX) {
            PyErr_SetString(PyExc_OverflowError, "timeout is too large");
            return NULL;
        }

        deadline = _PyTime_GetMonotonicClock() + timeout;
    }

    /* 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() */
    async_err = 0;
    do {
        Py_BEGIN_ALLOW_THREADS
        errno = 0;
        poll_result = poll(self->ufds, self->ufd_len, (int)ms);
        Py_END_ALLOW_THREADS

        if (errno != EINTR)
            break;

        /* poll() was interrupted by a signal */
        if (PyErr_CheckSignals()) {
            async_err = 1;
            break;
        }

        if (timeout >= 0) {
            timeout = deadline - _PyTime_GetMonotonicClock();
            if (timeout < 0) {
                poll_result = 0;
                break;
            }
            ms = _PyTime_AsMilliseconds(timeout, _PyTime_ROUND_CEILING);
            /* retry poll() with the recomputed timeout */
        }
    } while (1);

    self->poll_running = 0;

    if (poll_result < 0) {
        if (!async_err)
            PyErr_SetFromErrno(PyExc_OSError);
        return NULL;
    }

    /* build the result list */

    result_list = PyList_New(poll_result);
    if (!result_list)
        return NULL;

    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 = PyLong_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 = PyLong_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 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*/
    0,                          /*tp_getattr*/
    0,                      /*tp_setattr*/
    0,                          /*tp_reserved*/
    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*/
    0,                          /*tp_doc*/
    0,                          /*tp_traverse*/
    0,                          /*tp_clear*/
    0,                          /*tp_richcompare*/
    0,                          /*tp_weaklistoffset*/
    0,                          /*tp_iter*/
    0,                          /*tp_iternext*/
    poll_methods,               /*tp_methods*/
};

#ifdef HAVE_SYS_DEVPOLL_H
typedef struct {
    PyObject_HEAD
    int fd_devpoll;
    int max_n_fds;
    int n_fds;
    struct pollfd *fds;
} devpollObject;

static PyTypeObject devpoll_Type;

static PyObject *
devpoll_err_closed(void)
{
    PyErr_SetString(PyExc_ValueError, "I/O operation on closed devpoll object");
    return NULL;
}

static int devpoll_flush(devpollObject *self)
{
    int size, n;

    if (!self->n_fds) return 0;

    size = sizeof(struct pollfd)*self->n_fds;
    self->n_fds = 0;

    n = _Py_write(self->fd_devpoll, self->fds, size);
    if (n == -1)
        return -1;

    if (n < size) {
        /*
        ** Data writed to /dev/poll is a binary data structure. It is not
        ** clear what to do if a partial write occurred. For now, raise
        ** an exception and see if we actually found this problem in
        ** the wild.
        ** See http://bugs.python.org/issue6397.
        */
        PyErr_Format(PyExc_IOError, "failed to write all pollfds. "
                "Please, report at http://bugs.python.org/. "
                "Data to report: Size tried: %d, actual size written: %d.",
                size, n);
        return -1;
    }
    return 0;
}

static PyObject *
internal_devpoll_register(devpollObject *self, PyObject *args, int remove)
{
    PyObject *o;
    int fd;
    unsigned short events = POLLIN | POLLPRI | POLLOUT;

    if (self->fd_devpoll < 0)
        return devpoll_err_closed();

    if (!PyArg_ParseTuple(args, "O|O&:register", &o, ushort_converter, &events))
        return NULL;

    fd = PyObject_AsFileDescriptor(o);
    if (fd == -1) return NULL;

    if (remove) {
        self->fds[self->n_fds].fd = fd;
        self->fds[self->n_fds].events = POLLREMOVE;

        if (++self->n_fds == self->max_n_fds) {
            if (devpoll_flush(self))
                return NULL;
        }
    }

    self->fds[self->n_fds].fd = fd;
    self->fds[self->n_fds].events = (signed short)events;

    if (++self->n_fds == self->max_n_fds) {
        if (devpoll_flush(self))
            return NULL;
    }

    Py_RETURN_NONE;
}

PyDoc_STRVAR(devpoll_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 *
devpoll_register(devpollObject *self, PyObject *args)
{
    return internal_devpoll_register(self, args, 0);
}

PyDoc_STRVAR(devpoll_modify_doc,
"modify(fd[, eventmask]) -> None\n\n\
Modify a possible 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 *
devpoll_modify(devpollObject *self, PyObject *args)
{
    return internal_devpoll_register(self, args, 1);
}


PyDoc_STRVAR(devpoll_unregister_doc,
"unregister(fd) -> None\n\n\
Remove a file descriptor being tracked by the polling object.");

static PyObject *
devpoll_unregister(devpollObject *self, PyObject *o)
{
    int fd;

    if (self->fd_devpoll < 0)
        return devpoll_err_closed();

    fd = PyObject_AsFileDescriptor( o );
    if (fd == -1)
        return NULL;

    self->fds[self->n_fds].fd = fd;
    self->fds[self->n_fds].events = POLLREMOVE;

    if (++self->n_fds == self->max_n_fds) {
        if (devpoll_flush(self))
            return NULL;
    }

    Py_RETURN_NONE;
}

PyDoc_STRVAR(devpoll_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 *
devpoll_poll(devpollObject *self, PyObject *args)
{
    struct dvpoll dvp;
    PyObject *result_list = NULL, *timeout_obj = NULL;
    int poll_result, i;
    PyObject *value, *num1, *num2;
    _PyTime_t timeout, ms, deadline = 0;

    if (self->fd_devpoll < 0)
        return devpoll_err_closed();

    if (!PyArg_ParseTuple(args, "|O:poll", &timeout_obj)) {
        return NULL;
    }

    /* Check values for timeout */
    if (timeout_obj == NULL || timeout_obj == Py_None) {
        timeout = -1;
        ms = -1;
    }
    else {
        if (_PyTime_FromMillisecondsObject(&timeout, timeout_obj,
                                           _PyTime_ROUND_CEILING) < 0) {
            if (PyErr_ExceptionMatches(PyExc_TypeError)) {
                PyErr_SetString(PyExc_TypeError,
                                "timeout must be an integer or None");
            }
            return NULL;
        }

        ms = _PyTime_AsMilliseconds(timeout, _PyTime_ROUND_CEILING);
        if (ms < -1 || ms > INT_MAX) {
            PyErr_SetString(PyExc_OverflowError, "timeout is too large");
            return NULL;
        }
    }

    if (devpoll_flush(self))
        return NULL;

    dvp.dp_fds = self->fds;
    dvp.dp_nfds = self->max_n_fds;
    dvp.dp_timeout = (int)ms;

    if (timeout >= 0)
        deadline = _PyTime_GetMonotonicClock() + timeout;

    do {
        /* call devpoll() */
        Py_BEGIN_ALLOW_THREADS
        errno = 0;
        poll_result = ioctl(self->fd_devpoll, DP_POLL, &dvp);
        Py_END_ALLOW_THREADS

        if (errno != EINTR)
            break;

        /* devpoll() was interrupted by a signal */
        if (PyErr_CheckSignals())
            return NULL;

        if (timeout >= 0) {
            timeout = deadline - _PyTime_GetMonotonicClock();
            if (timeout < 0) {
                poll_result = 0;
                break;
            }
            ms = _PyTime_AsMilliseconds(timeout, _PyTime_ROUND_CEILING);
            dvp.dp_timeout = (int)ms;
            /* retry devpoll() with the recomputed timeout */
        }
    } while (1);

    if (poll_result < 0) {
        PyErr_SetFromErrno(PyExc_IOError);
        return NULL;
    }

    /* build the result list */
    result_list = PyList_New(poll_result);
    if (!result_list)
        return NULL;

    for (i = 0; i < poll_result; i++) {
        num1 = PyLong_FromLong(self->fds[i].fd);
        num2 = PyLong_FromLong(self->fds[i].revents);
        if ((num1 == NULL) || (num2 == NULL)) {
            Py_XDECREF(num1);
            Py_XDECREF(num2);
            goto error;
        }
        value = PyTuple_Pack(2, num1, num2);
        Py_DECREF(num1);
        Py_DECREF(num2);
        if (value == NULL)
            goto error;
        if ((PyList_SetItem(result_list, i, value)) == -1) {
            Py_DECREF(value);
            goto error;
        }
    }

    return result_list;

  error:
    Py_DECREF(result_list);
    return NULL;
}

static int
devpoll_internal_close(devpollObject *self)
{
    int save_errno = 0;
    if (self->fd_devpoll >= 0) {
        int fd = self->fd_devpoll;
        self->fd_devpoll = -1;
        Py_BEGIN_ALLOW_THREADS
        if (close(fd) < 0)
            save_errno = errno;
        Py_END_ALLOW_THREADS
    }
    return save_errno;
}

static PyObject*
devpoll_close(devpollObject *self)
{
    errno = devpoll_internal_close(self);
    if (errno < 0) {
        PyErr_SetFromErrno(PyExc_OSError);
        return NULL;
    }
    Py_RETURN_NONE;
}

PyDoc_STRVAR(devpoll_close_doc,
"close() -> None\n\
\n\
Close the devpoll file descriptor. Further operations on the devpoll\n\
object will raise an exception.");

static PyObject*
devpoll_get_closed(devpollObject *self)
{
    if (self->fd_devpoll < 0)
        Py_RETURN_TRUE;
    else
        Py_RETURN_FALSE;
}

static PyObject*
devpoll_fileno(devpollObject *self)
{
    if (self->fd_devpoll < 0)
        return devpoll_err_closed();
    return PyLong_FromLong(self->fd_devpoll);
}

PyDoc_STRVAR(devpoll_fileno_doc,
"fileno() -> int\n\
\n\
Return the file descriptor.");

static PyMethodDef devpoll_methods[] = {
    {"register",        (PyCFunction)devpoll_register,
     METH_VARARGS,  devpoll_register_doc},
    {"modify",          (PyCFunction)devpoll_modify,
     METH_VARARGS,  devpoll_modify_doc},
    {"unregister",      (PyCFunction)devpoll_unregister,
     METH_O,        devpoll_unregister_doc},
    {"poll",            (PyCFunction)devpoll_poll,
     METH_VARARGS,  devpoll_poll_doc},
    {"close",           (PyCFunction)devpoll_close,    METH_NOARGS,
     devpoll_close_doc},
    {"fileno",          (PyCFunction)devpoll_fileno,    METH_NOARGS,
     devpoll_fileno_doc},
    {NULL,              NULL}           /* sentinel */
};

static PyGetSetDef devpoll_getsetlist[] = {
    {"closed", (getter)devpoll_get_closed, NULL,
     "True if the devpoll object is closed"},
    {0},
};

static devpollObject *
newDevPollObject(void)
{
    devpollObject *self;
    int fd_devpoll, limit_result;
    struct pollfd *fds;
    struct rlimit limit;

    /*
    ** If we try to process more that getrlimit()
    ** fds, the kernel will give an error, so
    ** we set the limit here. It is a dynamic
    ** value, because we can change rlimit() anytime.
    */
    limit_result = getrlimit(RLIMIT_NOFILE, &limit);
    if (limit_result == -1) {
        PyErr_SetFromErrno(PyExc_OSError);
        return NULL;
    }

    fd_devpoll = _Py_open("/dev/poll", O_RDWR);
    if (fd_devpoll == -1)
        return NULL;

    fds = PyMem_NEW(struct pollfd, limit.rlim_cur);
    if (fds == NULL) {
        close(fd_devpoll);
        PyErr_NoMemory();
        return NULL;
    }

    self = PyObject_New(devpollObject, &devpoll_Type);
    if (self == NULL) {
        close(fd_devpoll);
        PyMem_DEL(fds);
        return NULL;
    }
    self->fd_devpoll = fd_devpoll;
    self->max_n_fds = limit.rlim_cur;
    self->n_fds = 0;
    self->fds = fds;

    return self;
}

static void
devpoll_dealloc(devpollObject *self)
{
    (void)devpoll_internal_close(self);
    PyMem_DEL(self->fds);
    PyObject_Del(self);
}

static PyTypeObject devpoll_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.devpoll",           /*tp_name*/
    sizeof(devpollObject),      /*tp_basicsize*/
    0,                          /*tp_itemsize*/
    /* methods */
    (destructor)devpoll_dealloc, /*tp_dealloc*/
    0,                          /*tp_print*/
    0,                          /*tp_getattr*/
    0,                          /*tp_setattr*/
    0,                          /*tp_reserved*/
    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*/
    0,                          /*tp_doc*/
    0,                          /*tp_traverse*/
    0,                          /*tp_clear*/
    0,                          /*tp_richcompare*/
    0,                          /*tp_weaklistoffset*/
    0,                          /*tp_iter*/
    0,                          /*tp_iternext*/
    devpoll_methods,            /*tp_methods*/
    0,                          /* tp_members */
    devpoll_getsetlist,         /* tp_getset */
};
#endif  /* HAVE_SYS_DEVPOLL_H */



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 HAVE_SYS_DEVPOLL_H
PyDoc_STRVAR(devpoll_doc,
"Returns a polling object, which supports registering and\n\
unregistering file descriptors, and then polling them for I/O events.");

static PyObject *
select_devpoll(PyObject *self, PyObject *unused)
{
    return (PyObject *)newDevPollObject();
}
#endif


#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 object");
    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, int flags, SOCKET fd)
{
    pyEpoll_Object *self;

    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
#ifdef HAVE_EPOLL_CREATE1
        flags |= EPOLL_CLOEXEC;
        if (flags)
            self->epfd = epoll_create1(flags);
        else
#endif
        self->epfd = epoll_create(sizehint);
        Py_END_ALLOW_THREADS
    }
    else {
        self->epfd = fd;
    }
    if (self->epfd < 0) {
        Py_DECREF(self);
        PyErr_SetFromErrno(PyExc_OSError);
        return NULL;
    }

#ifndef HAVE_EPOLL_CREATE1
    if (fd == -1 && _Py_set_inheritable(self->epfd, 0, NULL) < 0) {
        Py_DECREF(self);
        return NULL;
    }
#endif

    return (PyObject *)self;
}


static PyObject *
pyepoll_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
{
    int flags = 0, sizehint = FD_SETSIZE - 1;
    static char *kwlist[] = {"sizehint", "flags", NULL};

    if (!PyArg_ParseTupleAndKeywords(args, kwds, "|ii:epoll", kwlist,
                                     &sizehint, &flags))
        return NULL;
    if (sizehint < 0) {
        PyErr_SetString(PyExc_ValueError, "negative sizehint");
        return NULL;
    }

    return newPyEpoll_Object(type, sizehint, flags, -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_OSError);
        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 PyLong_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, FD_SETSIZE - 1, 0, 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_OSError);
        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 OSError 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 EPOLLIN | EPOLLOUT | EPOLLPRI.\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)
{
    static char *kwlist[] = {"timeout", "maxevents", NULL};
    PyObject *timeout_obj = NULL;
    int maxevents = -1;
    int nfds, i;
    PyObject *elist = NULL, *etuple = NULL;
    struct epoll_event *evs = NULL;
    _PyTime_t timeout, ms, deadline;

    if (self->epfd < 0)
        return pyepoll_err_closed();

    if (!PyArg_ParseTupleAndKeywords(args, kwds, "|Oi:poll", kwlist,
                                     &timeout_obj, &maxevents)) {
        return NULL;
    }

    if (timeout_obj == NULL || timeout_obj == Py_None) {
        timeout = -1;
        ms = -1;
        deadline = 0;   /* initialize to prevent gcc warning */
    }
    else {
        /* epoll_wait() has a resolution of 1 millisecond, round towards
           infinity to wait at least timeout seconds. */
        if (_PyTime_FromSecondsObject(&timeout, timeout_obj,
                                      _PyTime_ROUND_CEILING) < 0) {
            if (PyErr_ExceptionMatches(PyExc_TypeError)) {
                PyErr_SetString(PyExc_TypeError,
                                "timeout must be an integer or None");
            }
            return NULL;
        }

        ms = _PyTime_AsMilliseconds(timeout, _PyTime_ROUND_CEILING);
        if (ms < INT_MIN || ms > INT_MAX) {
            PyErr_SetString(PyExc_OverflowError, "timeout is too large");
            return NULL;
        }

        deadline = _PyTime_GetMonotonicClock() + timeout;
    }

    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) {
        PyErr_NoMemory();
        return NULL;
    }

    do {
        Py_BEGIN_ALLOW_THREADS
        errno = 0;
        nfds = epoll_wait(self->epfd, evs, maxevents, (int)ms);
        Py_END_ALLOW_THREADS

        if (errno != EINTR)
            break;

        /* poll() was interrupted by a signal */
        if (PyErr_CheckSignals())
            goto error;

        if (timeout >= 0) {
            timeout = deadline - _PyTime_GetMonotonicClock();
            if (timeout < 0) {
                nfds = 0;
                break;
            }
            ms = _PyTime_AsMilliseconds(timeout, _PyTime_ROUND_CEILING);
            /* retry epoll_wait() with the recomputed timeout */
        }
    } while(1);

    if (nfds < 0) {
        PyErr_SetFromErrno(PyExc_OSError);
        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 PyObject *
pyepoll_enter(pyEpoll_Object *self, PyObject *args)
{
    if (self->epfd < 0)
        return pyepoll_err_closed();

    Py_INCREF(self);
    return (PyObject *)self;
}

static PyObject *
pyepoll_exit(PyObject *self, PyObject *args)
{
    _Py_IDENTIFIER(close);

    return _PyObject_CallMethodId(self, &PyId_close, NULL);
}

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},
    {"__enter__",           (PyCFunction)pyepoll_enter,     METH_NOARGS,
     NULL},
    {"__exit__",           (PyCFunction)pyepoll_exit,     METH_VARARGS,
     NULL},
    {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, flags=0)\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_reserved */
    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 diction…