Adding upstream version 1.7.2.upstream/1.7.2upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

9 files changed, 3903 insertions, 0 deletions

diff --git a/poll/unix/epoll.c b/poll/unix/epoll.c
new file mode 100644
index 0000000..4ab03f6
--- /dev/null
+++ b/poll/unix/epoll.c
@@ -0,0 +1,490 @@
+/* Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "apr.h"
+#include "apr_poll.h"
+#include "apr_time.h"
+#include "apr_portable.h"
+#include "apr_arch_file_io.h"
+#include "apr_arch_networkio.h"
+#include "apr_arch_poll_private.h"
+#include "apr_arch_inherit.h"
+
+#if defined(HAVE_EPOLL)
+
+static apr_int16_t get_epoll_event(apr_int16_t event)
+{
+    apr_int16_t rv = 0;
+
+    if (event & APR_POLLIN)
+        rv |= EPOLLIN;
+    if (event & APR_POLLPRI)
+        rv |= EPOLLPRI;
+    if (event & APR_POLLOUT)
+        rv |= EPOLLOUT;
+    /* APR_POLLNVAL is not handled by epoll.  EPOLLERR and EPOLLHUP are return-only */
+
+    return rv;
+}
+
+static apr_int16_t get_epoll_revent(apr_int16_t event)
+{
+    apr_int16_t rv = 0;
+
+    if (event & EPOLLIN)
+        rv |= APR_POLLIN;
+    if (event & EPOLLPRI)
+        rv |= APR_POLLPRI;
+    if (event & EPOLLOUT)
+        rv |= APR_POLLOUT;
+    if (event & EPOLLERR)
+        rv |= APR_POLLERR;
+    if (event & EPOLLHUP)
+        rv |= APR_POLLHUP;
+    /* APR_POLLNVAL is not handled by epoll. */
+
+    return rv;
+}
+
+struct apr_pollset_private_t
+{
+    int epoll_fd;
+    struct epoll_event *pollset;
+    apr_pollfd_t *result_set;
+#if APR_HAS_THREADS
+    /* A thread mutex to protect operations on the rings */
+    apr_thread_mutex_t *ring_lock;
+#endif
+    /* A ring containing all of the pollfd_t that are active */
+    APR_RING_HEAD(pfd_query_ring_t, pfd_elem_t) query_ring;
+    /* A ring of pollfd_t that have been used, and then _remove()'d */
+    APR_RING_HEAD(pfd_free_ring_t, pfd_elem_t) free_ring;
+    /* A ring of pollfd_t where rings that have been _remove()`ed but
+        might still be inside a _poll() */
+    APR_RING_HEAD(pfd_dead_ring_t, pfd_elem_t) dead_ring;
+};
+
+static apr_status_t impl_pollset_cleanup(apr_pollset_t *pollset)
+{
+    close(pollset->p->epoll_fd);
+    return APR_SUCCESS;
+}
+
+
+static apr_status_t impl_pollset_create(apr_pollset_t *pollset,
+                                        apr_uint32_t size,
+                                        apr_pool_t *p,
+                                        apr_uint32_t flags)
+{
+    apr_status_t rv;
+    int fd;
+
+#ifdef HAVE_EPOLL_CREATE1
+    fd = epoll_create1(EPOLL_CLOEXEC);
+#else
+    fd = epoll_create(size);
+#endif
+    if (fd < 0) {
+        pollset->p = NULL;
+        return apr_get_netos_error();
+    }
+
+#ifndef HAVE_EPOLL_CREATE1
+    {
+        int fd_flags;
+
+        if ((fd_flags = fcntl(fd, F_GETFD)) == -1) {
+            rv = errno;
+            close(fd);
+            pollset->p = NULL;
+            return rv;
+        }
+
+        fd_flags |= FD_CLOEXEC;
+        if (fcntl(fd, F_SETFD, fd_flags) == -1) {
+            rv = errno;
+            close(fd);
+            pollset->p = NULL;
+            return rv;
+        }
+    }
+#endif
+
+    pollset->p = apr_palloc(p, sizeof(apr_pollset_private_t));
+#if APR_HAS_THREADS
+    if ((flags & APR_POLLSET_THREADSAFE) &&
+        !(flags & APR_POLLSET_NOCOPY) &&
+        ((rv = apr_thread_mutex_create(&pollset->p->ring_lock,
+                                       APR_THREAD_MUTEX_DEFAULT,
+                                       p)) != APR_SUCCESS)) {
+        close(fd);
+        pollset->p = NULL;
+        return rv;
+    }
+#else
+    if (flags & APR_POLLSET_THREADSAFE) {
+        close(fd);
+        pollset->p = NULL;
+        return APR_ENOTIMPL;
+    }
+#endif
+    pollset->p->epoll_fd = fd;
+    pollset->p->pollset = apr_palloc(p, size * sizeof(struct epoll_event));
+    pollset->p->result_set = apr_palloc(p, size * sizeof(apr_pollfd_t));
+
+    if (!(flags & APR_POLLSET_NOCOPY)) {
+        APR_RING_INIT(&pollset->p->query_ring, pfd_elem_t, link);
+        APR_RING_INIT(&pollset->p->free_ring, pfd_elem_t, link);
+        APR_RING_INIT(&pollset->p->dead_ring, pfd_elem_t, link);
+    }
+    return APR_SUCCESS;
+}
+
+static apr_status_t impl_pollset_add(apr_pollset_t *pollset,
+                                     const apr_pollfd_t *descriptor)
+{
+    struct epoll_event ev = {0};
+    int ret;
+    pfd_elem_t *elem = NULL;
+    apr_status_t rv = APR_SUCCESS;
+
+    ev.events = get_epoll_event(descriptor->reqevents);
+
+    if (pollset->flags & APR_POLLSET_NOCOPY) {
+        ev.data.ptr = (void *)descriptor;
+    }
+    else {
+        pollset_lock_rings();
+
+        if (!APR_RING_EMPTY(&(pollset->p->free_ring), pfd_elem_t, link)) {
+            elem = APR_RING_FIRST(&(pollset->p->free_ring));
+            APR_RING_REMOVE(elem, link);
+        }
+        else {
+            elem = (pfd_elem_t *) apr_palloc(pollset->pool, sizeof(pfd_elem_t));
+            APR_RING_ELEM_INIT(elem, link);
+        }
+        elem->pfd = *descriptor;
+        ev.data.ptr = elem;
+    }
+    if (descriptor->desc_type == APR_POLL_SOCKET) {
+        ret = epoll_ctl(pollset->p->epoll_fd, EPOLL_CTL_ADD,
+                        descriptor->desc.s->socketdes, &ev);
+    }
+    else {
+        ret = epoll_ctl(pollset->p->epoll_fd, EPOLL_CTL_ADD,
+                        descriptor->desc.f->filedes, &ev);
+    }
+
+    if (0 != ret) {
+        rv = apr_get_netos_error();
+    }
+
+    if (!(pollset->flags & APR_POLLSET_NOCOPY)) {
+        if (rv != APR_SUCCESS) {
+            APR_RING_INSERT_TAIL(&(pollset->p->free_ring), elem, pfd_elem_t, link);
+        }
+        else {
+            APR_RING_INSERT_TAIL(&(pollset->p->query_ring), elem, pfd_elem_t, link);
+        }
+        pollset_unlock_rings();
+    }
+
+    return rv;
+}
+
+static apr_status_t impl_pollset_remove(apr_pollset_t *pollset,
+                                        const apr_pollfd_t *descriptor)
+{
+    pfd_elem_t *ep;
+    apr_status_t rv = APR_SUCCESS;
+    struct epoll_event ev = {0}; /* ignored, but must be passed with
+                                  * kernel < 2.6.9
+                                  */
+    int ret;
+
+    if (descriptor->desc_type == APR_POLL_SOCKET) {
+        ret = epoll_ctl(pollset->p->epoll_fd, EPOLL_CTL_DEL,
+                        descriptor->desc.s->socketdes, &ev);
+    }
+    else {
+        ret = epoll_ctl(pollset->p->epoll_fd, EPOLL_CTL_DEL,
+                        descriptor->desc.f->filedes, &ev);
+    }
+    if (ret < 0) {
+        rv = APR_NOTFOUND;
+    }
+
+    if (!(pollset->flags & APR_POLLSET_NOCOPY)) {
+        pollset_lock_rings();
+
+        for (ep = APR_RING_FIRST(&(pollset->p->query_ring));
+             ep != APR_RING_SENTINEL(&(pollset->p->query_ring),
+                                     pfd_elem_t, link);
+             ep = APR_RING_NEXT(ep, link)) {
+                
+            if (descriptor->desc.s == ep->pfd.desc.s) {
+                APR_RING_REMOVE(ep, link);
+                APR_RING_INSERT_TAIL(&(pollset->p->dead_ring),
+                                     ep, pfd_elem_t, link);
+                break;
+            }
+        }
+
+        pollset_unlock_rings();
+    }
+
+    return rv;
+}
+
+static apr_status_t impl_pollset_poll(apr_pollset_t *pollset,
+                                           apr_interval_time_t timeout,
+                                           apr_int32_t *num,
+                                           const apr_pollfd_t **descriptors)
+{
+    int ret;
+    apr_status_t rv = APR_SUCCESS;
+
+    *num = 0;
+
+    if (timeout > 0) {
+        timeout /= 1000;
+    }
+
+    ret = epoll_wait(pollset->p->epoll_fd, pollset->p->pollset, pollset->nalloc,
+                     timeout);
+    if (ret < 0) {
+        rv = apr_get_netos_error();
+    }
+    else if (ret == 0) {
+        rv = APR_TIMEUP;
+    }
+    else {
+        int i, j;
+        const apr_pollfd_t *fdptr;
+
+        for (i = 0, j = 0; i < ret; i++) {
+            if (pollset->flags & APR_POLLSET_NOCOPY) {
+                fdptr = (apr_pollfd_t *)(pollset->p->pollset[i].data.ptr);
+            }
+            else {
+                fdptr = &(((pfd_elem_t *) (pollset->p->pollset[i].data.ptr))->pfd);
+            }
+            /* Check if the polled descriptor is our
+             * wakeup pipe. In that case do not put it result set.
+             */
+            if ((pollset->flags & APR_POLLSET_WAKEABLE) &&
+                fdptr->desc_type == APR_POLL_FILE &&
+                fdptr->desc.f == pollset->wakeup_pipe[0]) {
+                apr_poll_drain_wakeup_pipe(pollset->wakeup_pipe);
+                rv = APR_EINTR;
+            }
+            else {
+                pollset->p->result_set[j] = *fdptr;
+                pollset->p->result_set[j].rtnevents =
+                    get_epoll_revent(pollset->p->pollset[i].events);
+                j++;
+            }
+        }
+        if (((*num) = j)) { /* any event besides wakeup pipe? */
+            rv = APR_SUCCESS;
+
+            if (descriptors) {
+                *descriptors = pollset->p->result_set;
+            }
+        }
+    }
+
+    if (!(pollset->flags & APR_POLLSET_NOCOPY)) {
+        pollset_lock_rings();
+
+        /* Shift all PFDs in the Dead Ring to the Free Ring */
+        APR_RING_CONCAT(&(pollset->p->free_ring), &(pollset->p->dead_ring), pfd_elem_t, link);
+
+        pollset_unlock_rings();
+    }
+
+    return rv;
+}
+
+static const apr_pollset_provider_t impl = {
+    impl_pollset_create,
+    impl_pollset_add,
+    impl_pollset_remove,
+    impl_pollset_poll,
+    impl_pollset_cleanup,
+    "epoll"
+};
+
+const apr_pollset_provider_t *const apr_pollset_provider_epoll = &impl;
+
+static apr_status_t impl_pollcb_cleanup(apr_pollcb_t *pollcb)
+{
+    close(pollcb->fd);
+    return APR_SUCCESS;
+}
+
+static apr_status_t impl_pollcb_create(apr_pollcb_t *pollcb,
+                                       apr_uint32_t size,
+                                       apr_pool_t *p,
+                                       apr_uint32_t flags)
+{
+    int fd;
+    
+#ifdef HAVE_EPOLL_CREATE1
+    fd = epoll_create1(EPOLL_CLOEXEC);
+#else
+    fd = epoll_create(size);
+#endif
+    
+    if (fd < 0) {
+        return apr_get_netos_error();
+    }
+
+#ifndef HAVE_EPOLL_CREATE1
+    {
+        int fd_flags;
+        apr_status_t rv;
+
+        if ((fd_flags = fcntl(fd, F_GETFD)) == -1) {
+            rv = errno;
+            close(fd);
+            pollcb->fd = -1;
+            return rv;
+        }
+
+        fd_flags |= FD_CLOEXEC;
+        if (fcntl(fd, F_SETFD, fd_flags) == -1) {
+            rv = errno;
+            close(fd);
+            pollcb->fd = -1;
+            return rv;
+        }
+    }
+#endif
+    
+    pollcb->fd = fd;
+    pollcb->pollset.epoll = apr_palloc(p, size * sizeof(struct epoll_event));
+
+    return APR_SUCCESS;
+}
+
+static apr_status_t impl_pollcb_add(apr_pollcb_t *pollcb,
+                                    apr_pollfd_t *descriptor)
+{
+    struct epoll_event ev = { 0 };
+    int ret;
+    
+    ev.events = get_epoll_event(descriptor->reqevents);
+    ev.data.ptr = (void *) descriptor;
+
+    if (descriptor->desc_type == APR_POLL_SOCKET) {
+        ret = epoll_ctl(pollcb->fd, EPOLL_CTL_ADD,
+                        descriptor->desc.s->socketdes, &ev);
+    }
+    else {
+        ret = epoll_ctl(pollcb->fd, EPOLL_CTL_ADD,
+                        descriptor->desc.f->filedes, &ev);
+    }
+    
+    if (ret == -1) {
+        return apr_get_netos_error();
+    }
+    
+    return APR_SUCCESS;
+}
+
+static apr_status_t impl_pollcb_remove(apr_pollcb_t *pollcb,
+                                       apr_pollfd_t *descriptor)
+{
+    apr_status_t rv = APR_SUCCESS;
+    struct epoll_event ev = {0}; /* ignored, but must be passed with
+                                  * kernel < 2.6.9
+                                  */
+    int ret;
+    
+    if (descriptor->desc_type == APR_POLL_SOCKET) {
+        ret = epoll_ctl(pollcb->fd, EPOLL_CTL_DEL,
+                        descriptor->desc.s->socketdes, &ev);
+    }
+    else {
+        ret = epoll_ctl(pollcb->fd, EPOLL_CTL_DEL,
+                        descriptor->desc.f->filedes, &ev);
+    }
+    
+    if (ret < 0) {
+        rv = APR_NOTFOUND;
+    }
+    
+    return rv;
+}
+
+
+static apr_status_t impl_pollcb_poll(apr_pollcb_t *pollcb,
+                                     apr_interval_time_t timeout,
+                                     apr_pollcb_cb_t func,
+                                     void *baton)
+{
+    int ret, i;
+    apr_status_t rv = APR_SUCCESS;
+    
+    if (timeout > 0) {
+        timeout /= 1000;
+    }
+    
+    ret = epoll_wait(pollcb->fd, pollcb->pollset.epoll, pollcb->nalloc,
+                     timeout);
+    if (ret < 0) {
+        rv = apr_get_netos_error();
+    }
+    else if (ret == 0) {
+        rv = APR_TIMEUP;
+    }
+    else {
+        for (i = 0; i < ret; i++) {
+            apr_pollfd_t *pollfd = (apr_pollfd_t *)(pollcb->pollset.epoll[i].data.ptr);
+
+            if ((pollcb->flags & APR_POLLSET_WAKEABLE) &&
+                pollfd->desc_type == APR_POLL_FILE &&
+                pollfd->desc.f == pollcb->wakeup_pipe[0]) {
+                apr_poll_drain_wakeup_pipe(pollcb->wakeup_pipe);
+                return APR_EINTR;
+            }
+
+            pollfd->rtnevents = get_epoll_revent(pollcb->pollset.epoll[i].events);
+
+            rv = func(baton, pollfd);
+            if (rv) {
+                return rv;
+            }
+        }
+    }
+    
+    return rv;
+}
+
+static const apr_pollcb_provider_t impl_cb = {
+    impl_pollcb_create,
+    impl_pollcb_add,
+    impl_pollcb_remove,
+    impl_pollcb_poll,
+    impl_pollcb_cleanup,
+    "epoll"
+};
+
+const apr_pollcb_provider_t *const apr_pollcb_provider_epoll = &impl_cb;
+
+#endif /* HAVE_EPOLL */
diff --git a/poll/unix/kqueue.c b/poll/unix/kqueue.c
new file mode 100644
index 0000000..548464d
--- /dev/null
+++ b/poll/unix/kqueue.c
@@ -0,0 +1,505 @@
+/* Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "apr.h"
+#include "apr_poll.h"
+#include "apr_time.h"
+#include "apr_portable.h"
+#include "apr_arch_file_io.h"
+#include "apr_arch_networkio.h"
+#include "apr_arch_poll_private.h"
+#include "apr_arch_inherit.h"
+
+#ifdef HAVE_KQUEUE
+
+static apr_int16_t get_kqueue_revent(apr_int16_t event, apr_int16_t flags)
+{
+    apr_int16_t rv = 0;
+
+    if (event == EVFILT_READ)
+        rv |= APR_POLLIN;
+    else if (event == EVFILT_WRITE)
+        rv |= APR_POLLOUT;
+    if (flags & EV_EOF)
+        rv |= APR_POLLHUP;
+    /* APR_POLLPRI, APR_POLLERR, and APR_POLLNVAL are not handled by this
+     * implementation.
+     * TODO: See if EV_ERROR + certain system errors in the returned data field
+     * should map to APR_POLLNVAL.
+     */
+    return rv;
+}
+
+struct apr_pollset_private_t
+{
+    int kqueue_fd;
+    struct kevent kevent;
+    apr_uint32_t setsize;
+    struct kevent *ke_set;
+    apr_pollfd_t *result_set;
+#if APR_HAS_THREADS
+    /* A thread mutex to protect operations on the rings */
+    apr_thread_mutex_t *ring_lock;
+#endif
+    /* A ring containing all of the pollfd_t that are active */
+    APR_RING_HEAD(pfd_query_ring_t, pfd_elem_t) query_ring;
+    /* A ring of pollfd_t that have been used, and then _remove'd */
+    APR_RING_HEAD(pfd_free_ring_t, pfd_elem_t) free_ring;
+    /* A ring of pollfd_t where rings that have been _remove'd but
+       might still be inside a _poll */
+    APR_RING_HEAD(pfd_dead_ring_t, pfd_elem_t) dead_ring;
+};
+
+static apr_status_t impl_pollset_cleanup(apr_pollset_t *pollset)
+{
+    close(pollset->p->kqueue_fd);
+    return APR_SUCCESS;
+}
+
+static apr_status_t impl_pollset_create(apr_pollset_t *pollset,
+                                        apr_uint32_t size,
+                                        apr_pool_t *p,
+                                        apr_uint32_t flags)
+{
+    apr_status_t rv;
+    pollset->p = apr_palloc(p, sizeof(apr_pollset_private_t));
+#if APR_HAS_THREADS
+    if (flags & APR_POLLSET_THREADSAFE &&
+        ((rv = apr_thread_mutex_create(&pollset->p->ring_lock,
+                                       APR_THREAD_MUTEX_DEFAULT,
+                                       p)) != APR_SUCCESS)) {
+        pollset->p = NULL;
+        return rv;
+    }
+#else
+    if (flags & APR_POLLSET_THREADSAFE) {
+        pollset->p = NULL;
+        return APR_ENOTIMPL;
+    }
+#endif
+
+    /* POLLIN and POLLOUT are represented in different returned
+     * events, so we need 2 entries per descriptor in the result set,
+     * both for what is returned by kevent() and what is returned to
+     * the caller of apr_pollset_poll() (since it doesn't spend the
+     * CPU to coalesce separate APR_POLLIN and APR_POLLOUT events
+     * for the same descriptor)
+     */
+    pollset->p->setsize = 2 * size;
+
+    pollset->p->ke_set =
+        (struct kevent *) apr_palloc(p, pollset->p->setsize * sizeof(struct kevent));
+
+    memset(pollset->p->ke_set, 0, pollset->p->setsize * sizeof(struct kevent));
+
+    pollset->p->kqueue_fd = kqueue();
+
+    if (pollset->p->kqueue_fd == -1) {
+        pollset->p = NULL;
+        return apr_get_netos_error();
+    }
+
+    {
+        int flags;
+
+        if ((flags = fcntl(pollset->p->kqueue_fd, F_GETFD)) == -1) {
+            rv = errno;
+            close(pollset->p->kqueue_fd);
+            pollset->p = NULL;
+            return rv;
+        }
+
+        flags |= FD_CLOEXEC;
+        if (fcntl(pollset->p->kqueue_fd, F_SETFD, flags) == -1) {
+            rv = errno;
+            close(pollset->p->kqueue_fd);
+            pollset->p = NULL;
+            return rv;
+        }
+    }
+
+    pollset->p->result_set = apr_palloc(p, pollset->p->setsize * sizeof(apr_pollfd_t));
+
+    APR_RING_INIT(&pollset->p->query_ring, pfd_elem_t, link);
+    APR_RING_INIT(&pollset->p->free_ring, pfd_elem_t, link);
+    APR_RING_INIT(&pollset->p->dead_ring, pfd_elem_t, link);
+
+    return APR_SUCCESS;
+}
+
+static apr_status_t impl_pollset_add(apr_pollset_t *pollset,
+                                     const apr_pollfd_t *descriptor)
+{
+    apr_os_sock_t fd;
+    pfd_elem_t *elem;
+    apr_status_t rv = APR_SUCCESS;
+
+    pollset_lock_rings();
+
+    if (!APR_RING_EMPTY(&(pollset->p->free_ring), pfd_elem_t, link)) {
+        elem = APR_RING_FIRST(&(pollset->p->free_ring));
+        APR_RING_REMOVE(elem, link);
+    }
+    else {
+        elem = (pfd_elem_t *) apr_palloc(pollset->pool, sizeof(pfd_elem_t));
+        APR_RING_ELEM_INIT(elem, link);
+    }
+    elem->pfd = *descriptor;
+
+    if (descriptor->desc_type == APR_POLL_SOCKET) {
+        fd = descriptor->desc.s->socketdes;
+    }
+    else {
+        fd = descriptor->desc.f->filedes;
+    }
+
+    if (descriptor->reqevents & APR_POLLIN) {
+        EV_SET(&pollset->p->kevent, fd, EVFILT_READ, EV_ADD, 0, 0, elem);
+
+        if (kevent(pollset->p->kqueue_fd, &pollset->p->kevent, 1, NULL, 0,
+                   NULL) == -1) {
+            rv = apr_get_netos_error();
+        }
+    }
+
+    if (descriptor->reqevents & APR_POLLOUT && rv == APR_SUCCESS) {
+        EV_SET(&pollset->p->kevent, fd, EVFILT_WRITE, EV_ADD, 0, 0, elem);
+
+        if (kevent(pollset->p->kqueue_fd, &pollset->p->kevent, 1, NULL, 0,
+                   NULL) == -1) {
+            rv = apr_get_netos_error();
+        }
+    }
+
+    if (rv == APR_SUCCESS) {
+        APR_RING_INSERT_TAIL(&(pollset->p->query_ring), elem, pfd_elem_t, link);
+    }
+    else {
+        APR_RING_INSERT_TAIL(&(pollset->p->free_ring), elem, pfd_elem_t, link);
+    }
+
+    pollset_unlock_rings();
+
+    return rv;
+}
+
+static apr_status_t impl_pollset_remove(apr_pollset_t *pollset,
+                                        const apr_pollfd_t *descriptor)
+{
+    pfd_elem_t *ep;
+    apr_status_t rv;
+    apr_os_sock_t fd;
+
+    pollset_lock_rings();
+
+    if (descriptor->desc_type == APR_POLL_SOCKET) {
+        fd = descriptor->desc.s->socketdes;
+    }
+    else {
+        fd = descriptor->desc.f->filedes;
+    }
+
+    rv = APR_NOTFOUND; /* unless at least one of the specified conditions is */
+    if (descriptor->reqevents & APR_POLLIN) {
+        EV_SET(&pollset->p->kevent, fd, EVFILT_READ, EV_DELETE, 0, 0, NULL);
+
+        if (kevent(pollset->p->kqueue_fd, &pollset->p->kevent, 1, NULL, 0,
+                   NULL) != -1) {
+            rv = APR_SUCCESS;
+        }
+    }
+
+    if (descriptor->reqevents & APR_POLLOUT) {
+        EV_SET(&pollset->p->kevent, fd, EVFILT_WRITE, EV_DELETE, 0, 0, NULL);
+
+        if (kevent(pollset->p->kqueue_fd, &pollset->p->kevent, 1, NULL, 0,
+                   NULL) != -1) {
+            rv = APR_SUCCESS;
+        }
+    }
+
+    for (ep = APR_RING_FIRST(&(pollset->p->query_ring));
+         ep != APR_RING_SENTINEL(&(pollset->p->query_ring),
+                                 pfd_elem_t, link);
+         ep = APR_RING_NEXT(ep, link)) {
+
+        if (descriptor->desc.s == ep->pfd.desc.s) {
+            APR_RING_REMOVE(ep, link);
+            APR_RING_INSERT_TAIL(&(pollset->p->dead_ring),
+                                 ep, pfd_elem_t, link);
+            break;
+        }
+    }
+
+    pollset_unlock_rings();
+
+    return rv;
+}
+
+static apr_status_t impl_pollset_poll(apr_pollset_t *pollset,
+                                      apr_interval_time_t timeout,
+                                      apr_int32_t *num,
+                                      const apr_pollfd_t **descriptors)
+{
+    int ret;
+    struct timespec tv, *tvptr;
+    apr_status_t rv = APR_SUCCESS;
+
+    *num = 0;
+
+    if (timeout < 0) {
+        tvptr = NULL;
+    }
+    else {
+        tv.tv_sec = (long) apr_time_sec(timeout);
+        tv.tv_nsec = (long) apr_time_usec(timeout) * 1000;
+        tvptr = &tv;
+    }
+
+    ret = kevent(pollset->p->kqueue_fd, NULL, 0, pollset->p->ke_set,
+                 pollset->p->setsize, tvptr);
+    if (ret < 0) {
+        rv = apr_get_netos_error();
+    }
+    else if (ret == 0) {
+        rv = APR_TIMEUP;
+    }
+    else {
+        int i, j;
+        const apr_pollfd_t *fd;
+
+        for (i = 0, j = 0; i < ret; i++) {
+            fd = &((pfd_elem_t *)pollset->p->ke_set[i].udata)->pfd;
+            if ((pollset->flags & APR_POLLSET_WAKEABLE) &&
+                fd->desc_type == APR_POLL_FILE &&
+                fd->desc.f == pollset->wakeup_pipe[0]) {
+                apr_poll_drain_wakeup_pipe(pollset->wakeup_pipe);
+                rv = APR_EINTR;
+            }
+            else {
+                pollset->p->result_set[j] = *fd;
+                pollset->p->result_set[j].rtnevents =
+                        get_kqueue_revent(pollset->p->ke_set[i].filter,
+                                          pollset->p->ke_set[i].flags);
+                j++;
+            }
+        }
+        if ((*num = j)) { /* any event besides wakeup pipe? */
+            rv = APR_SUCCESS;
+            if (descriptors) {
+                *descriptors = pollset->p->result_set;
+            }
+        }
+    }
+
+    pollset_lock_rings();
+
+    /* Shift all PFDs in the Dead Ring to the Free Ring */
+    APR_RING_CONCAT(&(pollset->p->free_ring), &(pollset->p->dead_ring),
+                    pfd_elem_t, link);
+
+    pollset_unlock_rings();
+
+    return rv;
+}
+
+static const apr_pollset_provider_t impl = {
+    impl_pollset_create,
+    impl_pollset_add,
+    impl_pollset_remove,
+    impl_pollset_poll,
+    impl_pollset_cleanup,
+    "kqueue"
+};
+
+const apr_pollset_provider_t *apr_pollset_provider_kqueue = &impl;
+
+static apr_status_t impl_pollcb_cleanup(apr_pollcb_t *pollcb)
+{
+    close(pollcb->fd);
+    return APR_SUCCESS;
+}
+
+static apr_status_t impl_pollcb_create(apr_pollcb_t *pollcb,
+                                       apr_uint32_t size,
+                                       apr_pool_t *p,
+                                       apr_uint32_t flags)
+{
+    int fd;
+    
+    fd = kqueue();
+    if (fd < 0) {
+        return apr_get_netos_error();
+    }
+
+    {
+        int flags;
+        apr_status_t rv;
+
+        if ((flags = fcntl(fd, F_GETFD)) == -1) {
+            rv = errno;
+            close(fd);
+            pollcb->fd = -1;
+            return rv;
+        }
+
+        flags |= FD_CLOEXEC;
+        if (fcntl(fd, F_SETFD, flags) == -1) {
+            rv = errno;
+            close(fd);
+            pollcb->fd = -1;
+            return rv;
+        }
+    }
+ 
+    pollcb->fd = fd;
+    pollcb->pollset.ke = (struct kevent *) apr_pcalloc(p, 2 * size * sizeof(struct kevent));
+    
+    return APR_SUCCESS;
+}
+
+static apr_status_t impl_pollcb_add(apr_pollcb_t *pollcb,
+                                    apr_pollfd_t *descriptor)
+{
+    apr_os_sock_t fd;
+    struct kevent ev;
+    apr_status_t rv = APR_SUCCESS;
+    
+    if (descriptor->desc_type == APR_POLL_SOCKET) {
+        fd = descriptor->desc.s->socketdes;
+    }
+    else {
+        fd = descriptor->desc.f->filedes;
+    }
+    
+    if (descriptor->reqevents & APR_POLLIN) {
+        EV_SET(&ev, fd, EVFILT_READ, EV_ADD, 0, 0, descriptor);
+        
+        if (kevent(pollcb->fd, &ev, 1, NULL, 0, NULL) == -1) {
+            rv = apr_get_netos_error();
+        }
+    }
+    
+    if (descriptor->reqevents & APR_POLLOUT && rv == APR_SUCCESS) {
+        EV_SET(&ev, fd, EVFILT_WRITE, EV_ADD, 0, 0, descriptor);
+        
+        if (kevent(pollcb->fd, &ev, 1, NULL, 0, NULL) == -1) {
+            rv = apr_get_netos_error();
+        }
+    }
+    
+    return rv;
+}
+
+static apr_status_t impl_pollcb_remove(apr_pollcb_t *pollcb,
+                                       apr_pollfd_t *descriptor)
+{
+    apr_status_t rv;
+    struct kevent ev;
+    apr_os_sock_t fd;
+    
+    if (descriptor->desc_type == APR_POLL_SOCKET) {
+        fd = descriptor->desc.s->socketdes;
+    }
+    else {
+        fd = descriptor->desc.f->filedes;
+    }
+
+    rv = APR_NOTFOUND; /* unless at least one of the specified conditions is */
+    if (descriptor->reqevents & APR_POLLIN) {
+        EV_SET(&ev, fd, EVFILT_READ, EV_DELETE, 0, 0, NULL);
+        
+        if (kevent(pollcb->fd, &ev, 1, NULL, 0, NULL) != -1) {
+            rv = APR_SUCCESS;
+        }
+    }
+    
+    if (descriptor->reqevents & APR_POLLOUT) {
+        EV_SET(&ev, fd, EVFILT_WRITE, EV_DELETE, 0, 0, NULL);
+        
+        if (kevent(pollcb->fd, &ev, 1, NULL, 0, NULL) != -1) {
+            rv = APR_SUCCESS;
+        }
+    }
+    
+    return rv;
+}
+
+
+static apr_status_t impl_pollcb_poll(apr_pollcb_t *pollcb,
+                                     apr_interval_time_t timeout,
+                                     apr_pollcb_cb_t func,
+                                     void *baton)
+{
+    int ret, i;
+    struct timespec tv, *tvptr;
+    apr_status_t rv = APR_SUCCESS;
+    
+    if (timeout < 0) {
+        tvptr = NULL;
+    }
+    else {
+        tv.tv_sec = (long) apr_time_sec(timeout);
+        tv.tv_nsec = (long) apr_time_usec(timeout) * 1000;
+        tvptr = &tv;
+    }
+    
+    ret = kevent(pollcb->fd, NULL, 0, pollcb->pollset.ke, 2 * pollcb->nalloc,
+                 tvptr);
+
+    if (ret < 0) {
+        rv = apr_get_netos_error();
+    }
+    else if (ret == 0) {
+        rv = APR_TIMEUP;
+    }
+    else {
+        for (i = 0; i < ret; i++) {
+            apr_pollfd_t *pollfd = (apr_pollfd_t *)(pollcb->pollset.ke[i].udata);
+
+            if ((pollcb->flags & APR_POLLSET_WAKEABLE) &&
+                pollfd->desc_type == APR_POLL_FILE &&
+                pollfd->desc.f == pollcb->wakeup_pipe[0]) {
+                apr_poll_drain_wakeup_pipe(pollcb->wakeup_pipe);
+                return APR_EINTR;
+            }
+
+            pollfd->rtnevents = get_kqueue_revent(pollcb->pollset.ke[i].filter,
+                                                  pollcb->pollset.ke[i].flags);
+            
+            rv = func(baton, pollfd);
+            
+            if (rv) {
+                return rv;
+            }
+        }
+    }
+
+    return rv;
+}
+
+static const apr_pollcb_provider_t impl_cb = {
+    impl_pollcb_create,
+    impl_pollcb_add,
+    impl_pollcb_remove,
+    impl_pollcb_poll,
+    impl_pollcb_cleanup,
+    "kqueue"
+};
+
+const apr_pollcb_provider_t *apr_pollcb_provider_kqueue = &impl_cb;
+
+#endif /* HAVE_KQUEUE */
diff --git a/poll/unix/poll.c b/poll/unix/poll.c
new file mode 100644
index 0000000..5b878f1
--- /dev/null
+++ b/poll/unix/poll.c
@@ -0,0 +1,460 @@
+/* Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "apr.h"
+#include "apr_poll.h"
+#include "apr_time.h"
+#include "apr_portable.h"
+#include "apr_arch_file_io.h"
+#include "apr_arch_networkio.h"
+#include "apr_arch_misc.h"
+#include "apr_arch_poll_private.h"
+
+#if defined(HAVE_POLL)
+
+#ifdef HAVE_ALLOCA_H
+#include <alloca.h>
+#endif
+
+static apr_int16_t get_event(apr_int16_t event)
+{
+    apr_int16_t rv = 0;
+
+    if (event & APR_POLLIN)
+        rv |= POLLIN;
+    if (event & APR_POLLPRI)
+        rv |= POLLPRI;
+    if (event & APR_POLLOUT)
+        rv |= POLLOUT;
+    /* POLLERR, POLLHUP, and POLLNVAL aren't valid as requested events */
+
+    return rv;
+}
+
+static apr_int16_t get_revent(apr_int16_t event)
+{
+    apr_int16_t rv = 0;
+
+    if (event & POLLIN)
+        rv |= APR_POLLIN;
+    if (event & POLLPRI)
+        rv |= APR_POLLPRI;
+    if (event & POLLOUT)
+        rv |= APR_POLLOUT;
+    if (event & POLLERR)
+        rv |= APR_POLLERR;
+    if (event & POLLHUP)
+        rv |= APR_POLLHUP;
+    if (event & POLLNVAL)
+        rv |= APR_POLLNVAL;
+
+    return rv;
+}
+
+#ifdef POLL_USES_POLL
+
+#define SMALL_POLLSET_LIMIT  8
+
+APR_DECLARE(apr_status_t) apr_poll(apr_pollfd_t *aprset, apr_int32_t num,
+                                   apr_int32_t *nsds, 
+                                   apr_interval_time_t timeout)
+{
+    int i, num_to_poll;
+#ifdef HAVE_VLA
+    /* XXX: I trust that this is a segv when insufficient stack exists? */
+    struct pollfd pollset[num + 1]; /* +1 since allocating 0 is undefined behaviour */
+#elif defined(HAVE_ALLOCA)
+    struct pollfd *pollset = alloca(sizeof(struct pollfd) * num);
+    if (!pollset)
+        return APR_ENOMEM;
+#else
+    struct pollfd tmp_pollset[SMALL_POLLSET_LIMIT];
+    struct pollfd *pollset;
+
+    if (num <= SMALL_POLLSET_LIMIT) {
+        pollset = tmp_pollset;
+    }
+    else {
+        /* This does require O(n) to copy the descriptors to the internal
+         * mapping.
+         */
+        pollset = malloc(sizeof(struct pollfd) * num);
+        /* The other option is adding an apr_pool_abort() fn to invoke
+         * the pool's out of memory handler
+         */
+        if (!pollset)
+            return APR_ENOMEM;
+    }
+#endif
+    for (i = 0; i < num; i++) {
+        if (aprset[i].desc_type == APR_POLL_SOCKET) {
+            pollset[i].fd = aprset[i].desc.s->socketdes;
+        }
+        else if (aprset[i].desc_type == APR_POLL_FILE) {
+            pollset[i].fd = aprset[i].desc.f->filedes;
+        }
+        else {
+            break;
+        }
+        pollset[i].events = get_event(aprset[i].reqevents);
+    }
+    num_to_poll = i;
+
+    if (timeout > 0) {
+        timeout /= 1000; /* convert microseconds to milliseconds */
+    }
+
+    i = poll(pollset, num_to_poll, timeout);
+    (*nsds) = i;
+
+    if (i > 0) { /* poll() sets revents only if an event was signalled;
+                  * we don't promise to set rtnevents unless an event
+                  * was signalled
+                  */
+        for (i = 0; i < num; i++) {
+            aprset[i].rtnevents = get_revent(pollset[i].revents);
+        }
+    }
+    
+#if !defined(HAVE_VLA) && !defined(HAVE_ALLOCA)
+    if (num > SMALL_POLLSET_LIMIT) {
+        free(pollset);
+    }
+#endif
+
+    if ((*nsds) < 0) {
+        return apr_get_netos_error();
+    }
+    if ((*nsds) == 0) {
+        return APR_TIMEUP;
+    }
+    return APR_SUCCESS;
+}
+
+
+#endif /* POLL_USES_POLL */
+
+struct apr_pollset_private_t
+{
+    struct pollfd *pollset;
+    apr_pollfd_t *query_set;
+    apr_pollfd_t *result_set;
+};
+
+static apr_status_t impl_pollset_create(apr_pollset_t *pollset,
+                                        apr_uint32_t size,
+                                        apr_pool_t *p,
+                                        apr_uint32_t flags)
+{
+    if (flags & APR_POLLSET_THREADSAFE) {                
+        return APR_ENOTIMPL;
+    }
+#ifdef WIN32
+    if (!APR_HAVE_LATE_DLL_FUNC(WSAPoll)) {
+        return APR_ENOTIMPL;
+    }
+#endif
+    pollset->p = apr_palloc(p, sizeof(apr_pollset_private_t));
+    pollset->p->pollset = apr_palloc(p, size * sizeof(struct pollfd));
+    pollset->p->query_set = apr_palloc(p, size * sizeof(apr_pollfd_t));
+    pollset->p->result_set = apr_palloc(p, size * sizeof(apr_pollfd_t));
+
+    return APR_SUCCESS;
+}
+
+static apr_status_t impl_pollset_add(apr_pollset_t *pollset,
+                                     const apr_pollfd_t *descriptor)
+{
+    if (pollset->nelts == pollset->nalloc) {
+        return APR_ENOMEM;
+    }
+
+    pollset->p->query_set[pollset->nelts] = *descriptor;
+
+    if (descriptor->desc_type == APR_POLL_SOCKET) {
+        pollset->p->pollset[pollset->nelts].fd = descriptor->desc.s->socketdes;
+    }
+    else {
+#if APR_FILES_AS_SOCKETS
+        pollset->p->pollset[pollset->nelts].fd = descriptor->desc.f->filedes;
+#else
+        if ((pollset->flags & APR_POLLSET_WAKEABLE) &&
+            descriptor->desc.f == pollset->wakeup_pipe[0])
+            pollset->p->pollset[pollset->nelts].fd = (SOCKET)descriptor->desc.f->filedes;
+        else
+            return APR_EBADF;
+#endif
+    }
+    pollset->p->pollset[pollset->nelts].events =
+        get_event(descriptor->reqevents);
+    pollset->nelts++;
+
+    return APR_SUCCESS;
+}
+
+static apr_status_t impl_pollset_remove(apr_pollset_t *pollset,
+                                        const apr_pollfd_t *descriptor)
+{
+    apr_uint32_t i;
+
+    for (i = 0; i < pollset->nelts; i++) {
+        if (descriptor->desc.s == pollset->p->query_set[i].desc.s) {
+            /* Found an instance of the fd: remove this and any other copies */
+            apr_uint32_t dst = i;
+            apr_uint32_t old_nelts = pollset->nelts;
+            pollset->nelts--;
+            for (i++; i < old_nelts; i++) {
+                if (descriptor->desc.s == pollset->p->query_set[i].desc.s) {
+                    pollset->nelts--;
+                }
+                else {
+                    pollset->p->pollset[dst] = pollset->p->pollset[i];
+                    pollset->p->query_set[dst] = pollset->p->query_set[i];
+                    dst++;
+                }
+            }
+            return APR_SUCCESS;
+        }
+    }
+
+    return APR_NOTFOUND;
+}
+
+static apr_status_t impl_pollset_poll(apr_pollset_t *pollset,
+                                      apr_interval_time_t timeout,
+                                      apr_int32_t *num,
+                                      const apr_pollfd_t **descriptors)
+{
+    int ret;
+    apr_status_t rv = APR_SUCCESS;
+
+    *num = 0;
+
+#ifdef WIN32
+    /* WSAPoll() requires at least one socket. */
+    if (pollset->nelts == 0) {
+        if (timeout > 0) {
+            apr_sleep(timeout);
+            return APR_TIMEUP;
+        }
+        return APR_SUCCESS;
+    }
+    if (timeout > 0) {
+        timeout /= 1000;
+    }
+    ret = WSAPoll(pollset->p->pollset, pollset->nelts, (int)timeout);
+#else
+    if (timeout > 0) {
+        timeout /= 1000;
+    }
+    ret = poll(pollset->p->pollset, pollset->nelts, timeout);
+#endif
+    if (ret < 0) {
+        return apr_get_netos_error();
+    }
+    else if (ret == 0) {
+        return APR_TIMEUP;
+    }
+    else {
+        apr_uint32_t i, j;
+
+        for (i = 0, j = 0; i < pollset->nelts; i++) {
+            if (pollset->p->pollset[i].revents != 0) {
+                /* Check if the polled descriptor is our
+                 * wakeup pipe. In that case do not put it result set.
+                 */
+                if ((pollset->flags & APR_POLLSET_WAKEABLE) &&
+                    pollset->p->query_set[i].desc_type == APR_POLL_FILE &&
+                    pollset->p->query_set[i].desc.f == pollset->wakeup_pipe[0]) {
+                    apr_poll_drain_wakeup_pipe(pollset->wakeup_pipe);
+                    rv = APR_EINTR;
+                }
+                else {
+                    pollset->p->result_set[j] = pollset->p->query_set[i];
+                    pollset->p->result_set[j].rtnevents =
+                        get_revent(pollset->p->pollset[i].revents);
+                    j++;
+                }
+            }
+        }
+        if ((*num = j)) { /* any event besides wakeup pipe? */
+            rv = APR_SUCCESS;
+        }
+    }
+    if (descriptors && (*num))
+        *descriptors = pollset->p->result_set;
+    return rv;
+}
+
+static const apr_pollset_provider_t impl = {
+    impl_pollset_create,
+    impl_pollset_add,
+    impl_pollset_remove,
+    impl_pollset_poll,
+    NULL,
+    "poll"
+};
+
+const apr_pollset_provider_t *apr_pollset_provider_poll = &impl;
+
+/* Poll method pollcb.
+ * This is probably usable only for WIN32 having WSAPoll
+ */
+static apr_status_t impl_pollcb_create(apr_pollcb_t *pollcb,
+                                       apr_uint32_t size,
+                                       apr_pool_t *p,
+                                       apr_uint32_t flags)
+{
+#if APR_HAS_THREADS
+    return APR_ENOTIMPL;
+#else
+    pollcb->fd = -1;
+#ifdef WIN32
+    if (!APR_HAVE_LATE_DLL_FUNC(WSAPoll)) {
+        return APR_ENOTIMPL;
+    }
+#endif
+
+    pollcb->pollset.ps = apr_palloc(p, size * sizeof(struct pollfd));
+    pollcb->copyset = apr_palloc(p, size * sizeof(apr_pollfd_t *));
+
+    return APR_SUCCESS;
+#endif
+}
+
+static apr_status_t impl_pollcb_add(apr_pollcb_t *pollcb,
+                                    apr_pollfd_t *descriptor)
+{
+    if (pollcb->nelts == pollcb->nalloc) {
+        return APR_ENOMEM;
+    }
+
+    if (descriptor->desc_type == APR_POLL_SOCKET) {
+        pollcb->pollset.ps[pollcb->nelts].fd = descriptor->desc.s->socketdes;
+    }
+    else {
+#if APR_FILES_AS_SOCKETS
+        pollcb->pollset.ps[pollcb->nelts].fd = descriptor->desc.f->filedes;
+#else
+        return APR_EBADF;
+#endif
+    }
+
+    pollcb->pollset.ps[pollcb->nelts].events =
+        get_event(descriptor->reqevents);
+    pollcb->copyset[pollcb->nelts] = descriptor;
+    pollcb->nelts++;
+    
+    return APR_SUCCESS;
+}
+
+static apr_status_t impl_pollcb_remove(apr_pollcb_t *pollcb,
+                                       apr_pollfd_t *descriptor)
+{
+    apr_uint32_t i;
+
+    for (i = 0; i < pollcb->nelts; i++) {
+        if (descriptor->desc.s == pollcb->copyset[i]->desc.s) {
+            /* Found an instance of the fd: remove this and any other copies */
+            apr_uint32_t dst = i;
+            apr_uint32_t old_nelts = pollcb->nelts;
+            pollcb->nelts--;
+            for (i++; i < old_nelts; i++) {
+                if (descriptor->desc.s == pollcb->copyset[i]->desc.s) {
+                    pollcb->nelts--;
+                }
+                else {
+                    pollcb->pollset.ps[dst] = pollcb->pollset.ps[i];
+                    pollcb->copyset[dst] = pollcb->copyset[i];
+                    dst++;
+                }
+            }
+            return APR_SUCCESS;
+        }
+    }
+
+    return APR_NOTFOUND;
+}
+
+static apr_status_t impl_pollcb_poll(apr_pollcb_t *pollcb,
+                                     apr_interval_time_t timeout,
+                                     apr_pollcb_cb_t func,
+                                     void *baton)
+{
+    int ret;
+    apr_status_t rv = APR_SUCCESS;
+    apr_uint32_t i;
+
+#ifdef WIN32
+    /* WSAPoll() requires at least one socket. */
+    if (pollcb->nelts == 0) {
+        if (timeout > 0) {
+            apr_sleep(timeout);
+            return APR_TIMEUP;
+        }
+        return APR_SUCCESS;
+    }
+    if (timeout > 0) {
+        timeout /= 1000;
+    }
+    ret = WSAPoll(pollcb->pollset.ps, pollcb->nelts, (int)timeout);
+#else
+    if (timeout > 0) {
+        timeout /= 1000;
+    }
+    ret = poll(pollcb->pollset.ps, pollcb->nelts, timeout);
+#endif
+    if (ret < 0) {
+        return apr_get_netos_error();
+    }
+    else if (ret == 0) {
+        return APR_TIMEUP;
+    }
+    else {
+        for (i = 0; i < pollcb->nelts; i++) {
+            if (pollcb->pollset.ps[i].revents != 0) {
+                apr_pollfd_t *pollfd = pollcb->copyset[i];
+
+                if ((pollcb->flags & APR_POLLSET_WAKEABLE) &&
+                    pollfd->desc_type == APR_POLL_FILE &&
+                    pollfd->desc.f == pollcb->wakeup_pipe[0]) {
+                    apr_poll_drain_wakeup_pipe(pollcb->wakeup_pipe);
+                    return APR_EINTR;
+                }
+
+                pollfd->rtnevents = get_revent(pollcb->pollset.ps[i].revents);                    
+                rv = func(baton, pollfd);
+                if (rv) {
+                    return rv;
+                }
+            }
+        }
+    }
+    return rv;
+}
+
+static const apr_pollcb_provider_t impl_cb = {
+    impl_pollcb_create,
+    impl_pollcb_add,
+    impl_pollcb_remove,
+    impl_pollcb_poll,
+    NULL,
+    "poll"
+};
+
+const apr_pollcb_provider_t *apr_pollcb_provider_poll = &impl_cb;
+
+#endif /* HAVE_POLL */
diff --git a/poll/unix/pollcb.c b/poll/unix/pollcb.c
new file mode 100644
index 0000000..a63ad5c
--- /dev/null
+++ b/poll/unix/pollcb.c
@@ -0,0 +1,224 @@
+/* Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifdef WIN32
+/* POSIX defines 1024 for the FD_SETSIZE */
+#define FD_SETSIZE 1024
+#endif
+
+#include "apr.h"
+#include "apr_poll.h"
+#include "apr_time.h"
+#include "apr_portable.h"
+#include "apr_arch_file_io.h"
+#include "apr_arch_networkio.h"
+#include "apr_arch_poll_private.h"
+
+static apr_pollset_method_e pollset_default_method = POLLSET_DEFAULT_METHOD;
+#if defined(HAVE_KQUEUE)
+extern const apr_pollcb_provider_t *apr_pollcb_provider_kqueue;
+#endif
+#if defined(HAVE_PORT_CREATE)
+extern const apr_pollcb_provider_t *apr_pollcb_provider_port;
+#endif
+#if defined(HAVE_EPOLL)
+extern const apr_pollcb_provider_t *apr_pollcb_provider_epoll;
+#endif
+#if defined(HAVE_POLL)
+extern const apr_pollcb_provider_t *apr_pollcb_provider_poll;
+#endif
+
+static const apr_pollcb_provider_t *pollcb_provider(apr_pollset_method_e method)
+{
+    const apr_pollcb_provider_t *provider = NULL;
+    switch (method) {
+        case APR_POLLSET_KQUEUE:
+#if defined(HAVE_KQUEUE)
+            provider = apr_pollcb_provider_kqueue;
+#endif
+        break;
+        case APR_POLLSET_PORT:
+#if defined(HAVE_PORT_CREATE)
+            provider = apr_pollcb_provider_port;
+#endif
+        break;
+        case APR_POLLSET_EPOLL:
+#if defined(HAVE_EPOLL)
+            provider = apr_pollcb_provider_epoll;
+#endif
+        break;
+        case APR_POLLSET_POLL:
+#if defined(HAVE_POLL)
+            provider = apr_pollcb_provider_poll;
+#endif
+        break;
+        case APR_POLLSET_SELECT:
+        case APR_POLLSET_AIO_MSGQ:
+        case APR_POLLSET_DEFAULT:
+        break;
+    }
+    return provider;
+}
+
+static apr_status_t pollcb_cleanup(void *p)
+{
+    apr_pollcb_t *pollcb = (apr_pollcb_t *) p;
+
+    if (pollcb->provider->cleanup) {
+        (*pollcb->provider->cleanup)(pollcb);
+    }
+    if (pollcb->flags & APR_POLLSET_WAKEABLE) {
+        apr_poll_close_wakeup_pipe(pollcb->wakeup_pipe);
+    }
+
+    return APR_SUCCESS;
+}
+
+APR_DECLARE(apr_status_t) apr_pollcb_create_ex(apr_pollcb_t **ret_pollcb,
+                                               apr_uint32_t size,
+                                               apr_pool_t *p,
+                                               apr_uint32_t flags,
+                                               apr_pollset_method_e method)
+{
+    apr_status_t rv;
+    apr_pollcb_t *pollcb;
+    const apr_pollcb_provider_t *provider = NULL;
+
+    *ret_pollcb = NULL;
+
+ #ifdef WIN32
+    /* This will work only if ws2_32.dll has WSAPoll funtion.
+     * We could check the presence of the function here,
+     * but someone might implement other pollcb method in
+     * the future.
+     */
+    if (method == APR_POLLSET_DEFAULT) {
+        method = APR_POLLSET_POLL;
+    }
+ #endif
+
+    if (method == APR_POLLSET_DEFAULT)
+        method = pollset_default_method;
+    while (provider == NULL) {
+        provider = pollcb_provider(method);
+        if (!provider) {
+            if ((flags & APR_POLLSET_NODEFAULT) == APR_POLLSET_NODEFAULT)
+                return APR_ENOTIMPL;
+            if (method == pollset_default_method)
+                return APR_ENOTIMPL;
+            method = pollset_default_method;
+        }
+    }
+
+    if (flags & APR_POLLSET_WAKEABLE) {
+        /* Add room for wakeup descriptor */
+        size++;
+    }
+
+    pollcb = apr_palloc(p, sizeof(*pollcb));
+    pollcb->nelts = 0;
+    pollcb->nalloc = size;
+    pollcb->flags = flags;
+    pollcb->pool = p;
+    pollcb->provider = provider;
+
+    rv = (*provider->create)(pollcb, size, p, flags);
+    if (rv == APR_ENOTIMPL) {
+        if (method == pollset_default_method) {
+            return rv;
+        }
+
+        if ((flags & APR_POLLSET_NODEFAULT) == APR_POLLSET_NODEFAULT) {
+            return rv;
+        }
+
+        /* Try with default provider */
+        provider = pollcb_provider(pollset_default_method);
+        if (!provider) {
+            return APR_ENOTIMPL;
+        }
+        rv = (*provider->create)(pollcb, size, p, flags);
+        if (rv != APR_SUCCESS) {
+            return rv;
+        }
+        pollcb->provider = provider;
+    }
+    else if (rv != APR_SUCCESS) {
+        return rv;
+    }
+
+    if (flags & APR_POLLSET_WAKEABLE) {
+        /* Create wakeup pipe */
+        if ((rv = apr_poll_create_wakeup_pipe(pollcb->pool, &pollcb->wakeup_pfd,
+                                              pollcb->wakeup_pipe)) 
+                != APR_SUCCESS) {
+            return rv;
+        }
+
+        if ((rv = apr_pollcb_add(pollcb, &pollcb->wakeup_pfd)) != APR_SUCCESS) {
+            return rv;
+        }
+    }
+    if ((flags & APR_POLLSET_WAKEABLE) || provider->cleanup)
+        apr_pool_cleanup_register(p, pollcb, pollcb_cleanup,
+                                  apr_pool_cleanup_null);
+
+    *ret_pollcb = pollcb;
+    return APR_SUCCESS;
+}
+
+APR_DECLARE(apr_status_t) apr_pollcb_create(apr_pollcb_t **pollcb,
+                                            apr_uint32_t size,
+                                            apr_pool_t *p,
+                                            apr_uint32_t flags)
+{
+    apr_pollset_method_e method = APR_POLLSET_DEFAULT;
+    return apr_pollcb_create_ex(pollcb, size, p, flags, method);
+}
+
+APR_DECLARE(apr_status_t) apr_pollcb_add(apr_pollcb_t *pollcb,
+                                         apr_pollfd_t *descriptor)
+{
+    return (*pollcb->provider->add)(pollcb, descriptor);
+}
+
+APR_DECLARE(apr_status_t) apr_pollcb_remove(apr_pollcb_t *pollcb,
+                                            apr_pollfd_t *descriptor)
+{
+    return (*pollcb->provider->remove)(pollcb, descriptor);
+}
+
+
+APR_DECLARE(apr_status_t) apr_pollcb_poll(apr_pollcb_t *pollcb,
+                                          apr_interval_time_t timeout,
+                                          apr_pollcb_cb_t func,
+                                          void *baton)
+{
+    return (*pollcb->provider->poll)(pollcb, timeout, func, baton);
+}
+
+APR_DECLARE(apr_status_t) apr_pollcb_wakeup(apr_pollcb_t *pollcb)
+{
+    if (pollcb->flags & APR_POLLSET_WAKEABLE)
+        return apr_file_putc(1, pollcb->wakeup_pipe[1]);
+    else
+        return APR_EINIT;
+}
+
+APR_DECLARE(const char *) apr_pollcb_method_name(apr_pollcb_t *pollcb)
+{
+    return pollcb->provider->name;
+}
diff --git a/poll/unix/pollset.c b/poll/unix/pollset.c
new file mode 100644
index 0000000..11b5736
--- /dev/null
+++ b/poll/unix/pollset.c
@@ -0,0 +1,247 @@
+/* Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifdef WIN32
+/* POSIX defines 1024 for the FD_SETSIZE */
+#define FD_SETSIZE 1024
+#endif
+
+#include "apr.h"
+#include "apr_poll.h"
+#include "apr_time.h"
+#include "apr_portable.h"
+#include "apr_arch_file_io.h"
+#include "apr_arch_networkio.h"
+#include "apr_arch_poll_private.h"
+#include "apr_arch_inherit.h"
+
+static apr_pollset_method_e pollset_default_method = POLLSET_DEFAULT_METHOD;
+
+static apr_status_t pollset_cleanup(void *p)
+{
+    apr_pollset_t *pollset = (apr_pollset_t *) p;
+    if (pollset->provider->cleanup) {
+        (*pollset->provider->cleanup)(pollset);
+    }
+    if (pollset->flags & APR_POLLSET_WAKEABLE) {
+        apr_poll_close_wakeup_pipe(pollset->wakeup_pipe);
+    }
+
+    return APR_SUCCESS;
+}
+
+#if defined(HAVE_KQUEUE)
+extern const apr_pollset_provider_t *apr_pollset_provider_kqueue;
+#endif
+#if defined(HAVE_PORT_CREATE)
+extern const apr_pollset_provider_t *apr_pollset_provider_port;
+#endif
+#if defined(HAVE_EPOLL)
+extern const apr_pollset_provider_t *apr_pollset_provider_epoll;
+#endif
+#if defined(HAVE_AIO_MSGQ)
+extern const apr_pollset_provider_t *apr_pollset_provider_aio_msgq;
+#endif
+#if defined(HAVE_POLL)
+extern const apr_pollset_provider_t *apr_pollset_provider_poll;
+#endif
+extern const apr_pollset_provider_t *apr_pollset_provider_select;
+
+static const apr_pollset_provider_t *pollset_provider(apr_pollset_method_e method)
+{
+    const apr_pollset_provider_t *provider = NULL;
+    switch (method) {
+        case APR_POLLSET_KQUEUE:
+#if defined(HAVE_KQUEUE)
+            provider = apr_pollset_provider_kqueue;
+#endif
+        break;
+        case APR_POLLSET_PORT:
+#if defined(HAVE_PORT_CREATE)
+            provider = apr_pollset_provider_port;
+#endif
+        break;
+        case APR_POLLSET_EPOLL:
+#if defined(HAVE_EPOLL)
+            provider = apr_pollset_provider_epoll;
+#endif
+        break;
+        case APR_POLLSET_AIO_MSGQ:
+#if defined(HAVE_AIO_MSGQ)
+            provider = apr_pollset_provider_aio_msgq;
+#endif
+        break;
+        case APR_POLLSET_POLL:
+#if defined(HAVE_POLL)
+            provider = apr_pollset_provider_poll;
+#endif
+        break;
+        case APR_POLLSET_SELECT:
+            provider = apr_pollset_provider_select;
+        break;
+        case APR_POLLSET_DEFAULT:
+        break;
+    }
+    return provider;
+}
+
+APR_DECLARE(apr_status_t) apr_pollset_create_ex(apr_pollset_t **ret_pollset,
+                                                apr_uint32_t size,
+                                                apr_pool_t *p,
+                                                apr_uint32_t flags,
+                                                apr_pollset_method_e method)
+{
+    apr_status_t rv;
+    apr_pollset_t *pollset;
+    const apr_pollset_provider_t *provider = NULL;
+
+    *ret_pollset = NULL;
+
+ #ifdef WIN32
+    /* Favor WSAPoll if supported.
+     * This will work only if ws2_32.dll has WSAPoll funtion.
+     * In other cases it will fall back to select() method unless
+     * the APR_POLLSET_NODEFAULT is added to the flags.
+     */
+    if (method == APR_POLLSET_DEFAULT) {
+        method = APR_POLLSET_POLL;
+    }
+ #endif
+
+    if (method == APR_POLLSET_DEFAULT)
+        method = pollset_default_method;
+    while (provider == NULL) {
+        provider = pollset_provider(method);
+        if (!provider) {
+            if ((flags & APR_POLLSET_NODEFAULT) == APR_POLLSET_NODEFAULT)
+                return APR_ENOTIMPL;
+            if (method == pollset_default_method)
+                return APR_ENOTIMPL;
+            method = pollset_default_method;
+        }
+    }
+    if (flags & APR_POLLSET_WAKEABLE) {
+        /* Add room for wakeup descriptor */
+        size++;
+    }
+
+    pollset = apr_palloc(p, sizeof(*pollset));
+    pollset->nelts = 0;
+    pollset->nalloc = size;
+    pollset->pool = p;
+    pollset->flags = flags;
+    pollset->provider = provider;
+
+    rv = (*provider->create)(pollset, size, p, flags);
+    if (rv == APR_ENOTIMPL) {
+        if (method == pollset_default_method) {
+            return rv;
+        }
+        provider = pollset_provider(pollset_default_method);
+        if (!provider) {
+            return APR_ENOTIMPL;
+        }
+        rv = (*provider->create)(pollset, size, p, flags);
+        if (rv != APR_SUCCESS) {
+            return rv;
+        }
+        pollset->provider = provider;
+    }
+    else if (rv != APR_SUCCESS) {
+        return rv;
+    }
+    if (flags & APR_POLLSET_WAKEABLE) {
+        /* Create wakeup pipe */
+        if ((rv = apr_poll_create_wakeup_pipe(pollset->pool, &pollset->wakeup_pfd,
+                                              pollset->wakeup_pipe))
+                != APR_SUCCESS) {
+            return rv;
+        }
+
+        if ((rv = apr_pollset_add(pollset, &pollset->wakeup_pfd)) != APR_SUCCESS) {
+            return rv;
+        }
+    }
+    if ((flags & APR_POLLSET_WAKEABLE) || provider->cleanup)
+        apr_pool_cleanup_register(p, pollset, pollset_cleanup,
+                                  apr_pool_cleanup_null);
+
+    *ret_pollset = pollset;
+    return APR_SUCCESS;
+}
+
+APR_DECLARE(const char *) apr_pollset_method_name(apr_pollset_t *pollset)
+{
+    return pollset->provider->name;
+}
+
+APR_DECLARE(const char *) apr_poll_method_defname(void)
+{
+    const apr_pollset_provider_t *provider = NULL;
+
+    provider = pollset_provider(pollset_default_method);
+    if (provider)
+        return provider->name;
+    else
+        return "unknown";
+}
+
+APR_DECLARE(apr_status_t) apr_pollset_create(apr_pollset_t **pollset,
+                                             apr_uint32_t size,
+                                             apr_pool_t *p,
+                                             apr_uint32_t flags)
+{
+    apr_pollset_method_e method = APR_POLLSET_DEFAULT;
+    return apr_pollset_create_ex(pollset, size, p, flags, method);
+}
+
+APR_DECLARE(apr_status_t) apr_pollset_destroy(apr_pollset_t * pollset)
+{
+    if (pollset->flags & APR_POLLSET_WAKEABLE ||
+        pollset->provider->cleanup)
+        return apr_pool_cleanup_run(pollset->pool, pollset,
+                                    pollset_cleanup);
+    else
+        return APR_SUCCESS;
+}
+
+APR_DECLARE(apr_status_t) apr_pollset_wakeup(apr_pollset_t *pollset)
+{
+    if (pollset->flags & APR_POLLSET_WAKEABLE)
+        return apr_file_putc(1, pollset->wakeup_pipe[1]);
+    else
+        return APR_EINIT;
+}
+
+APR_DECLARE(apr_status_t) apr_pollset_add(apr_pollset_t *pollset,
+                                          const apr_pollfd_t *descriptor)
+{
+    return (*pollset->provider->add)(pollset, descriptor);
+}
+
+APR_DECLARE(apr_status_t) apr_pollset_remove(apr_pollset_t *pollset,
+                                             const apr_pollfd_t *descriptor)
+{
+    return (*pollset->provider->remove)(pollset, descriptor);
+}
+
+APR_DECLARE(apr_status_t) apr_pollset_poll(apr_pollset_t *pollset,
+                                           apr_interval_time_t timeout,
+                                           apr_int32_t *num,
+                                           const apr_pollfd_t **descriptors)
+{
+    return (*pollset->provider->poll)(pollset, timeout, num, descriptors);
+}
diff --git a/poll/unix/port.c b/poll/unix/port.c
new file mode 100644
index 0000000..c1e5994
--- /dev/null
+++ b/poll/unix/port.c
@@ -0,0 +1,594 @@
+/* Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "apr.h"
+#include "apr_poll.h"
+#include "apr_time.h"
+#include "apr_portable.h"
+#include "apr_atomic.h"
+#include "apr_arch_file_io.h"
+#include "apr_arch_networkio.h"
+#include "apr_arch_poll_private.h"
+#include "apr_arch_inherit.h"
+
+#if defined(HAVE_PORT_CREATE)
+
+static apr_int16_t get_event(apr_int16_t event)
+{
+    apr_int16_t rv = 0;
+
+    if (event & APR_POLLIN)
+        rv |= POLLIN;
+    if (event & APR_POLLPRI)
+        rv |= POLLPRI;
+    if (event & APR_POLLOUT)
+        rv |= POLLOUT;
+    /* POLLERR, POLLHUP, and POLLNVAL aren't valid as requested events */
+
+    return rv;
+}
+
+static apr_int16_t get_revent(apr_int16_t event)
+{
+    apr_int16_t rv = 0;
+
+    if (event & POLLIN)
+        rv |= APR_POLLIN;
+    if (event & POLLPRI)
+        rv |= APR_POLLPRI;
+    if (event & POLLOUT)
+        rv |= APR_POLLOUT;
+    if (event & POLLERR)
+        rv |= APR_POLLERR;
+    if (event & POLLHUP)
+        rv |= APR_POLLHUP;
+    if (event & POLLNVAL)
+        rv |= APR_POLLNVAL;
+
+    return rv;
+}
+
+
+struct apr_pollset_private_t
+{
+    int port_fd;
+    port_event_t *port_set;
+    apr_pollfd_t *result_set;
+#if APR_HAS_THREADS
+    /* A thread mutex to protect operations on the rings */
+    apr_thread_mutex_t *ring_lock;
+#endif
+    /* A ring containing all of the pollfd_t that are active */
+    APR_RING_HEAD(pfd_query_ring_t, pfd_elem_t) query_ring;
+    /* A ring containing the pollfd_t that will be added on the
+     * next call to apr_pollset_poll().
+     */
+    APR_RING_HEAD(pfd_add_ring_t, pfd_elem_t) add_ring;
+    /* A ring of pollfd_t that have been used, and then _remove'd */
+    APR_RING_HEAD(pfd_free_ring_t, pfd_elem_t) free_ring;
+    /* A ring of pollfd_t where rings that have been _remove'd but
+       might still be inside a _poll */
+    APR_RING_HEAD(pfd_dead_ring_t, pfd_elem_t) dead_ring;
+    /* number of threads in poll */
+    volatile apr_uint32_t waiting;
+};
+
+static apr_status_t call_port_getn(int port, port_event_t list[], 
+                                   unsigned int max, unsigned int *nget,
+                                   apr_interval_time_t timeout)
+{
+    struct timespec tv, *tvptr;
+    int ret;
+    apr_status_t rv = APR_SUCCESS;
+
+    if (timeout < 0) {
+        tvptr = NULL;
+    }
+    else {
+        tv.tv_sec = (long) apr_time_sec(timeout);
+        tv.tv_nsec = (long) apr_time_usec(timeout) * 1000;
+        tvptr = &tv;
+    }
+
+    list[0].portev_user = (void *)-1; /* so we can double check that an
+                                       * event was returned
+                                       */
+
+    ret = port_getn(port, list, max, nget, tvptr);
+    /* Note: 32-bit port_getn() on Solaris 10 x86 returns large negative 
+     * values instead of 0 when returning immediately.
+     */
+
+    if (ret == -1) {
+        rv = apr_get_netos_error();
+
+        switch(rv) {
+        case EINTR:
+        case ETIME:
+            if (*nget > 0 && list[0].portev_user != (void *)-1) {
+                /* This confusing API can return an event at the same time
+                 * that it reports EINTR or ETIME.  If that occurs, just
+                 * report the event.  With EINTR, nget can be > 0 without
+                 * any event, so check that portev_user was filled in.
+                 *
+                 * (Maybe it will be simplified; see thread
+                 *   http://mail.opensolaris.org
+                 *   /pipermail/networking-discuss/2009-August/011979.html
+                 *  This code will still work afterwards.)
+                 */
+                rv = APR_SUCCESS;
+                break;
+            }
+            if (rv == ETIME) {
+                rv = APR_TIMEUP;
+            }
+        /* fall-through */
+        default:
+            *nget = 0;
+        }
+    }
+    else if (*nget == 0) {
+        rv = APR_TIMEUP;
+    }
+
+    return rv;
+}
+
+static apr_status_t impl_pollset_cleanup(apr_pollset_t *pollset)
+{
+    close(pollset->p->port_fd);
+    return APR_SUCCESS;
+}
+
+static apr_status_t impl_pollset_create(apr_pollset_t *pollset,
+                                             apr_uint32_t size,
+                                             apr_pool_t *p,
+                                             apr_uint32_t flags)
+{
+    apr_status_t rv = APR_SUCCESS;
+    pollset->p = apr_palloc(p, sizeof(apr_pollset_private_t));
+#if APR_HAS_THREADS
+    if (flags & APR_POLLSET_THREADSAFE &&
+        ((rv = apr_thread_mutex_create(&pollset->p->ring_lock,
+                                       APR_THREAD_MUTEX_DEFAULT,
+                                       p)) != APR_SUCCESS)) {
+        pollset->p = NULL;
+        return rv;
+    }
+#else
+    if (flags & APR_POLLSET_THREADSAFE) {
+        pollset->p = NULL;
+        return APR_ENOTIMPL;
+    }
+#endif
+    pollset->p->waiting = 0;
+
+    pollset->p->port_set = apr_palloc(p, size * sizeof(port_event_t));
+
+    pollset->p->port_fd = port_create();
+
+    if (pollset->p->port_fd < 0) {
+        pollset->p = NULL;
+        return apr_get_netos_error();
+    }
+
+    {
+        int flags;
+
+        if ((flags = fcntl(pollset->p->port_fd, F_GETFD)) == -1) {
+            rv = errno;
+            close(pollset->p->port_fd);
+            pollset->p = NULL;
+            return rv;
+        }
+
+        flags |= FD_CLOEXEC;
+        if (fcntl(pollset->p->port_fd, F_SETFD, flags) == -1) {
+            rv = errno;
+            close(pollset->p->port_fd);
+            pollset->p = NULL;
+            return rv;
+        }
+    }
+
+    pollset->p->result_set = apr_palloc(p, size * sizeof(apr_pollfd_t));
+
+    APR_RING_INIT(&pollset->p->query_ring, pfd_elem_t, link);
+    APR_RING_INIT(&pollset->p->add_ring, pfd_elem_t, link);
+    APR_RING_INIT(&pollset->p->free_ring, pfd_elem_t, link);
+    APR_RING_INIT(&pollset->p->dead_ring, pfd_elem_t, link);
+
+    return rv;
+}
+
+static apr_status_t impl_pollset_add(apr_pollset_t *pollset,
+                                     const apr_pollfd_t *descriptor)
+{
+    apr_os_sock_t fd;
+    pfd_elem_t *elem;
+    int res;
+    apr_status_t rv = APR_SUCCESS;
+
+    pollset_lock_rings();
+
+    if (!APR_RING_EMPTY(&(pollset->p->free_ring), pfd_elem_t, link)) {
+        elem = APR_RING_FIRST(&(pollset->p->free_ring));
+        APR_RING_REMOVE(elem, link);
+    }
+    else {
+        elem = (pfd_elem_t *) apr_palloc(pollset->pool, sizeof(pfd_elem_t));
+        APR_RING_ELEM_INIT(elem, link);
+        elem->on_query_ring = 0;
+    }
+    elem->pfd = *descriptor;
+
+    if (descriptor->desc_type == APR_POLL_SOCKET) {
+        fd = descriptor->desc.s->socketdes;
+    }
+    else {
+        fd = descriptor->desc.f->filedes;
+    }
+
+    /* If another thread is polling, notify the kernel immediately; otherwise,
+     * wait until the next call to apr_pollset_poll().
+     */
+    if (apr_atomic_read32(&pollset->p->waiting)) {
+        res = port_associate(pollset->p->port_fd, PORT_SOURCE_FD, fd, 
+                             get_event(descriptor->reqevents), (void *)elem);
+
+        if (res < 0) {
+            rv = apr_get_netos_error();
+            APR_RING_INSERT_TAIL(&(pollset->p->free_ring), elem, pfd_elem_t, link);
+        }
+        else {
+            elem->on_query_ring = 1;
+            APR_RING_INSERT_TAIL(&(pollset->p->query_ring), elem, pfd_elem_t, link);
+        }
+    } 
+    else {
+        APR_RING_INSERT_TAIL(&(pollset->p->add_ring), elem, pfd_elem_t, link);
+    }
+
+    pollset_unlock_rings();
+
+    return rv;
+}
+
+static apr_status_t impl_pollset_remove(apr_pollset_t *pollset,
+                                        const apr_pollfd_t *descriptor)
+{
+    apr_os_sock_t fd;
+    pfd_elem_t *ep;
+    apr_status_t rv = APR_SUCCESS;
+    int res;
+    int err = 0;
+    int found;
+
+    pollset_lock_rings();
+
+    if (descriptor->desc_type == APR_POLL_SOCKET) {
+        fd = descriptor->desc.s->socketdes;
+    }
+    else {
+        fd = descriptor->desc.f->filedes;
+    }
+
+    /* Search the add ring first.  This ring is often shorter,
+     * and it often contains the descriptor being removed.  
+     * (For the common scenario where apr_pollset_poll() 
+     * returns activity for the descriptor and the descriptor
+     * is then removed from the pollset, it will have just 
+     * been moved to the add ring by apr_pollset_poll().)
+     *
+     * If it is on the add ring, it isn't associated with the
+     * event port yet/anymore.
+     */
+    found = 0;
+    for (ep = APR_RING_FIRST(&(pollset->p->add_ring));
+         ep != APR_RING_SENTINEL(&(pollset->p->add_ring),
+                                 pfd_elem_t, link);
+         ep = APR_RING_NEXT(ep, link)) {
+
+        if (descriptor->desc.s == ep->pfd.desc.s) {
+            found = 1;
+            APR_RING_REMOVE(ep, link);
+            APR_RING_INSERT_TAIL(&(pollset->p->free_ring),
+                                 ep, pfd_elem_t, link);
+            break;
+        }
+    }
+
+    if (!found) {
+        res = port_dissociate(pollset->p->port_fd, PORT_SOURCE_FD, fd);
+
+        if (res < 0) {
+            /* The expected case for this failure is that another
+             * thread's call to port_getn() returned this fd and
+             * disassociated the fd from the event port, and 
+             * impl_pollset_poll() is blocked on the ring lock,
+             * which this thread holds.
+             */
+            err = errno;
+            rv = APR_NOTFOUND;
+        }
+
+        for (ep = APR_RING_FIRST(&(pollset->p->query_ring));
+             ep != APR_RING_SENTINEL(&(pollset->p->query_ring),
+                                     pfd_elem_t, link);
+             ep = APR_RING_NEXT(ep, link)) {
+
+            if (descriptor->desc.s == ep->pfd.desc.s) {
+                APR_RING_REMOVE(ep, link);
+                ep->on_query_ring = 0;
+                APR_RING_INSERT_TAIL(&(pollset->p->dead_ring),
+                                     ep, pfd_elem_t, link);
+                if (ENOENT == err) {
+                    rv = APR_SUCCESS;
+                }
+                break;
+            }
+        }
+    }
+
+    pollset_unlock_rings();
+
+    return rv;
+}
+
+static apr_status_t impl_pollset_poll(apr_pollset_t *pollset,
+                                      apr_interval_time_t timeout,
+                                      apr_int32_t *num,
+                                      const apr_pollfd_t **descriptors)
+{
+    apr_os_sock_t fd;
+    int ret;
+    unsigned int nget, i;
+    apr_int32_t j;
+    pfd_elem_t *ep;
+    apr_status_t rv = APR_SUCCESS;
+
+    *num = 0;
+    nget = 1;
+
+    pollset_lock_rings();
+
+    apr_atomic_inc32(&pollset->p->waiting);
+
+    while (!APR_RING_EMPTY(&(pollset->p->add_ring), pfd_elem_t, link)) {
+        ep = APR_RING_FIRST(&(pollset->p->add_ring));
+        APR_RING_REMOVE(ep, link);
+
+        if (ep->pfd.desc_type == APR_POLL_SOCKET) {
+            fd = ep->pfd.desc.s->socketdes;
+        }
+        else {
+            fd = ep->pfd.desc.f->filedes;
+        }
+
+        ret = port_associate(pollset->p->port_fd, PORT_SOURCE_FD, 
+                             fd, get_event(ep->pfd.reqevents), ep);
+        if (ret < 0) {
+            rv = apr_get_netos_error();
+            APR_RING_INSERT_TAIL(&(pollset->p->free_ring), ep, pfd_elem_t, link);
+            break;
+        }
+
+        ep->on_query_ring = 1;
+        APR_RING_INSERT_TAIL(&(pollset->p->query_ring), ep, pfd_elem_t, link);
+    }
+
+    pollset_unlock_rings();
+
+    if (rv != APR_SUCCESS) {
+        apr_atomic_dec32(&pollset->p->waiting);
+        return rv;
+    }
+
+    rv = call_port_getn(pollset->p->port_fd, pollset->p->port_set, 
+                        pollset->nalloc, &nget, timeout);
+
+    /* decrease the waiting ASAP to reduce the window for calling 
+       port_associate within apr_pollset_add() */
+    apr_atomic_dec32(&pollset->p->waiting);
+
+    pollset_lock_rings();
+
+    for (i = 0, j = 0; i < nget; i++) {
+        ep = (pfd_elem_t *)pollset->p->port_set[i].portev_user;
+        if ((pollset->flags & APR_POLLSET_WAKEABLE) &&
+            ep->pfd.desc_type == APR_POLL_FILE &&
+            ep->pfd.desc.f == pollset->wakeup_pipe[0]) {
+            apr_poll_drain_wakeup_pipe(pollset->wakeup_pipe);
+            rv = APR_EINTR;
+        }
+        else {
+            pollset->p->result_set[j] = ep->pfd;
+            pollset->p->result_set[j].rtnevents =
+                get_revent(pollset->p->port_set[i].portev_events);
+            j++;
+        }
+        /* If the ring element is still on the query ring, move it
+         * to the add ring for re-association with the event port
+         * later.  (It may have already been moved to the dead ring
+         * by a call to pollset_remove on another thread.)
+         */
+        if (ep->on_query_ring) {
+            APR_RING_REMOVE(ep, link);
+            ep->on_query_ring = 0;
+            APR_RING_INSERT_TAIL(&(pollset->p->add_ring), ep,
+                                 pfd_elem_t, link);
+        }
+    }
+    if ((*num = j)) { /* any event besides wakeup pipe? */
+        rv = APR_SUCCESS;
+        if (descriptors) {
+            *descriptors = pollset->p->result_set;
+        }
+    }
+
+    /* Shift all PFDs in the Dead Ring to the Free Ring */
+    APR_RING_CONCAT(&(pollset->p->free_ring), &(pollset->p->dead_ring), pfd_elem_t, link);
+
+    pollset_unlock_rings();
+
+    return rv;
+}
+
+static const apr_pollset_provider_t impl = {
+    impl_pollset_create,
+    impl_pollset_add,
+    impl_pollset_remove,
+    impl_pollset_poll,
+    impl_pollset_cleanup,
+    "port"
+};
+
+const apr_pollset_provider_t *apr_pollset_provider_port = &impl;
+
+static apr_status_t impl_pollcb_cleanup(apr_pollcb_t *pollcb)
+{
+    close(pollcb->fd);
+    return APR_SUCCESS;
+}
+
+static apr_status_t impl_pollcb_create(apr_pollcb_t *pollcb,
+                                       apr_uint32_t size,
+                                       apr_pool_t *p,
+                                       apr_uint32_t flags)
+{
+    pollcb->fd = port_create();
+
+    if (pollcb->fd < 0) {
+        return apr_get_netos_error();
+    }
+
+    {
+        int flags;
+        apr_status_t rv;
+
+        if ((flags = fcntl(pollcb->fd, F_GETFD)) == -1) {
+            rv = errno;
+            close(pollcb->fd);
+            pollcb->fd = -1;
+            return rv;
+        }
+
+        flags |= FD_CLOEXEC;
+        if (fcntl(pollcb->fd, F_SETFD, flags) == -1) {
+            rv = errno;
+            close(pollcb->fd);
+            pollcb->fd = -1;
+            return rv;
+        }
+    }
+
+    pollcb->pollset.port = apr_palloc(p, size * sizeof(port_event_t));
+
+    return APR_SUCCESS;
+}
+
+static apr_status_t impl_pollcb_add(apr_pollcb_t *pollcb,
+                                    apr_pollfd_t *descriptor)
+{
+    int ret, fd;
+
+    if (descriptor->desc_type == APR_POLL_SOCKET) {
+        fd = descriptor->desc.s->socketdes;
+    }
+    else {
+        fd = descriptor->desc.f->filedes;
+    }
+
+    ret = port_associate(pollcb->fd, PORT_SOURCE_FD, fd,
+                         get_event(descriptor->reqevents), descriptor);
+
+    if (ret == -1) {
+        return apr_get_netos_error();
+    }
+
+    return APR_SUCCESS;
+}
+
+static apr_status_t impl_pollcb_remove(apr_pollcb_t *pollcb,
+                                       apr_pollfd_t *descriptor)
+{
+    int fd, ret;
+
+    if (descriptor->desc_type == APR_POLL_SOCKET) {
+        fd = descriptor->desc.s->socketdes;
+    }
+    else {
+        fd = descriptor->desc.f->filedes;
+    }
+
+    ret = port_dissociate(pollcb->fd, PORT_SOURCE_FD, fd);
+
+    if (ret < 0) {
+        return APR_NOTFOUND;
+    }
+
+    return APR_SUCCESS;
+}
+
+static apr_status_t impl_pollcb_poll(apr_pollcb_t *pollcb,
+                                     apr_interval_time_t timeout,
+                                     apr_pollcb_cb_t func,
+                                     void *baton)
+{
+    apr_status_t rv;
+    unsigned int nget = 1;
+
+    rv = call_port_getn(pollcb->fd, pollcb->pollset.port, pollcb->nalloc,
+                        &nget, timeout);
+
+    if (nget) {
+        unsigned int i;
+
+        for (i = 0; i < nget; i++) {
+            apr_pollfd_t *pollfd = (apr_pollfd_t *)(pollcb->pollset.port[i].portev_user);
+
+            if ((pollcb->flags & APR_POLLSET_WAKEABLE) &&
+                pollfd->desc_type == APR_POLL_FILE &&
+                pollfd->desc.f == pollcb->wakeup_pipe[0]) {
+                apr_poll_drain_wakeup_pipe(pollcb->wakeup_pipe);
+                return APR_EINTR;
+            }
+
+            pollfd->rtnevents = get_revent(pollcb->pollset.port[i].portev_events);
+
+            rv = func(baton, pollfd);
+            if (rv) {
+                return rv;
+            }
+            rv = apr_pollcb_add(pollcb, pollfd);
+        }
+    }
+
+    return rv;
+}
+
+static const apr_pollcb_provider_t impl_cb = {
+    impl_pollcb_create,
+    impl_pollcb_add,
+    impl_pollcb_remove,
+    impl_pollcb_poll,
+    impl_pollcb_cleanup,
+    "port"
+};
+
+const apr_pollcb_provider_t *apr_pollcb_provider_port = &impl_cb;
+
+#endif /* HAVE_PORT_CREATE */
diff --git a/poll/unix/select.c b/poll/unix/select.c
new file mode 100644
index 0000000..51be3c1
--- /dev/null
+++ b/poll/unix/select.c
@@ -0,0 +1,449 @@
+/* Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifdef WIN32
+/* POSIX defines 1024 for the FD_SETSIZE */
+#define FD_SETSIZE 1024
+#endif
+
+#include "apr.h"
+#include "apr_poll.h"
+#include "apr_time.h"
+#include "apr_portable.h"
+#include "apr_arch_file_io.h"
+#include "apr_arch_networkio.h"
+#include "apr_arch_poll_private.h"
+
+#ifdef POLL_USES_SELECT
+
+APR_DECLARE(apr_status_t) apr_poll(apr_pollfd_t *aprset, int num,
+                                   apr_int32_t *nsds,
+                                   apr_interval_time_t timeout)
+{
+    fd_set readset, writeset, exceptset;
+    int rv, i;
+    int maxfd = -1;
+    struct timeval tv, *tvptr;
+#ifdef NETWARE
+    apr_datatype_e set_type = APR_NO_DESC;
+#endif
+
+#ifdef WIN32
+    /* On Win32, select() must be presented with at least one socket to
+     * poll on, or select() will return WSAEINVAL.  So, we'll just
+     * short-circuit and bail now.
+     */
+    if (num == 0) {
+        (*nsds) = 0;
+        if (timeout > 0) {
+            apr_sleep(timeout);
+            return APR_TIMEUP;
+        }
+        return APR_SUCCESS;
+    }
+#endif
+
+    if (timeout < 0) {
+        tvptr = NULL;
+    }
+    else {
+        tv.tv_sec = (long) apr_time_sec(timeout);
+        tv.tv_usec = (long) apr_time_usec(timeout);
+        tvptr = &tv;
+    }
+
+    FD_ZERO(&readset);
+    FD_ZERO(&writeset);
+    FD_ZERO(&exceptset);
+
+    for (i = 0; i < num; i++) {
+        apr_os_sock_t fd;
+
+        aprset[i].rtnevents = 0;
+
+        if (aprset[i].desc_type == APR_POLL_SOCKET) {
+#ifdef NETWARE
+            if (HAS_PIPES(set_type)) {
+                return APR_EBADF;
+            }
+            else {
+                set_type = APR_POLL_SOCKET;
+            }
+#endif
+            fd = aprset[i].desc.s->socketdes;
+        }
+        else if (aprset[i].desc_type == APR_POLL_FILE) {
+#if !APR_FILES_AS_SOCKETS
+            return APR_EBADF;
+#else
+#ifdef NETWARE
+            if (aprset[i].desc.f->is_pipe && !HAS_SOCKETS(set_type)) {
+                set_type = APR_POLL_FILE;
+            }
+            else
+                return APR_EBADF;
+#endif /* NETWARE */
+
+            fd = aprset[i].desc.f->filedes;
+
+#endif /* APR_FILES_AS_SOCKETS */
+        }
+        else {
+            break;
+        }
+#if !defined(WIN32) && !defined(NETWARE)        /* socket sets handled with array of handles */
+        if (fd >= FD_SETSIZE) {
+            /* XXX invent new error code so application has a clue */
+            return APR_EBADF;
+        }
+#endif
+        if (aprset[i].reqevents & APR_POLLIN) {
+            FD_SET(fd, &readset);
+        }
+        if (aprset[i].reqevents & APR_POLLOUT) {
+            FD_SET(fd, &writeset);
+        }
+        if (aprset[i].reqevents &
+            (APR_POLLPRI | APR_POLLERR | APR_POLLHUP | APR_POLLNVAL)) {
+            FD_SET(fd, &exceptset);
+        }
+        if ((int) fd > maxfd) {
+            maxfd = (int) fd;
+        }
+    }
+
+#ifdef NETWARE
+    if (HAS_PIPES(set_type)) {
+        rv = pipe_select(maxfd + 1, &readset, &writeset, &exceptset, tvptr);
+    }
+    else {
+#endif
+
+        rv = select(maxfd + 1, &readset, &writeset, &exceptset, tvptr);
+
+#ifdef NETWARE
+    }
+#endif
+
+    (*nsds) = rv;
+    if ((*nsds) == 0) {
+        return APR_TIMEUP;
+    }
+    if ((*nsds) < 0) {
+        return apr_get_netos_error();
+    }
+
+    (*nsds) = 0;
+    for (i = 0; i < num; i++) {
+        apr_os_sock_t fd;
+
+        if (aprset[i].desc_type == APR_POLL_SOCKET) {
+            fd = aprset[i].desc.s->socketdes;
+        }
+        else if (aprset[i].desc_type == APR_POLL_FILE) {
+#if !APR_FILES_AS_SOCKETS
+            return APR_EBADF;
+#else
+            fd = aprset[i].desc.f->filedes;
+#endif
+        }
+        else {
+            break;
+        }
+        if (FD_ISSET(fd, &readset)) {
+            aprset[i].rtnevents |= APR_POLLIN;
+        }
+        if (FD_ISSET(fd, &writeset)) {
+            aprset[i].rtnevents |= APR_POLLOUT;
+        }
+        if (FD_ISSET(fd, &exceptset)) {
+            aprset[i].rtnevents |= APR_POLLERR;
+        }
+        if (aprset[i].rtnevents) {
+            (*nsds)++;
+        }
+    }
+
+    return APR_SUCCESS;
+}
+
+#endif /* POLL_USES_SELECT */
+
+struct apr_pollset_private_t
+{
+    fd_set readset, writeset, exceptset;
+    int maxfd;
+    apr_pollfd_t *query_set;
+    apr_pollfd_t *result_set;
+    apr_uint32_t flags;
+#ifdef NETWARE
+    int set_type;
+#endif
+};
+
+static apr_status_t impl_pollset_create(apr_pollset_t *pollset,
+                                        apr_uint32_t size,
+                                        apr_pool_t *p,
+                                        apr_uint32_t flags)
+{
+    if (flags & APR_POLLSET_THREADSAFE) {                
+        pollset->p = NULL;
+        return APR_ENOTIMPL;
+    }
+#ifdef FD_SETSIZE
+    if (size > FD_SETSIZE) {
+        pollset->p = NULL;
+        return APR_EINVAL;
+    }
+#endif
+    pollset->p = apr_palloc(p, sizeof(apr_pollset_private_t));
+    FD_ZERO(&(pollset->p->readset));
+    FD_ZERO(&(pollset->p->writeset));
+    FD_ZERO(&(pollset->p->exceptset));
+    pollset->p->maxfd = 0;
+#ifdef NETWARE
+    pollset->p->set_type = APR_NO_DESC;
+#endif
+    pollset->p->query_set = apr_palloc(p, size * sizeof(apr_pollfd_t));
+    pollset->p->result_set = apr_palloc(p, size * sizeof(apr_pollfd_t));
+
+    return APR_SUCCESS;
+}
+
+static apr_status_t impl_pollset_add(apr_pollset_t *pollset,
+                                     const apr_pollfd_t *descriptor)
+{
+    apr_os_sock_t fd;
+
+    if (pollset->nelts == pollset->nalloc) {
+        return APR_ENOMEM;
+    }
+
+    pollset->p->query_set[pollset->nelts] = *descriptor;
+
+    if (descriptor->desc_type == APR_POLL_SOCKET) {
+#ifdef NETWARE
+        /* NetWare can't handle mixed descriptor types in select() */
+        if (HAS_PIPES(pollset->p->set_type)) {
+            return APR_EBADF;
+        }
+        else {
+            pollset->p->set_type = APR_POLL_SOCKET;
+        }
+#endif
+        fd = descriptor->desc.s->socketdes;
+    }
+    else {
+#if !APR_FILES_AS_SOCKETS
+        if ((pollset->flags & APR_POLLSET_WAKEABLE) &&
+            descriptor->desc.f == pollset->wakeup_pipe[0])
+            fd = (apr_os_sock_t)descriptor->desc.f->filedes;
+        else
+            return APR_EBADF;
+#else
+#ifdef NETWARE
+        /* NetWare can't handle mixed descriptor types in select() */
+        if (descriptor->desc.f->is_pipe && !HAS_SOCKETS(pollset->p->set_type)) {
+            pollset->p->set_type = APR_POLL_FILE;
+            fd = descriptor->desc.f->filedes;
+        }
+        else {
+            return APR_EBADF;
+        }
+#else
+        fd = descriptor->desc.f->filedes;
+#endif
+#endif
+    }
+#if !defined(WIN32) && !defined(NETWARE)        /* socket sets handled with array of handles */
+    if (fd >= FD_SETSIZE) {
+        /* XXX invent new error code so application has a clue */
+        return APR_EBADF;
+    }
+#endif
+    if (descriptor->reqevents & APR_POLLIN) {
+        FD_SET(fd, &(pollset->p->readset));
+    }
+    if (descriptor->reqevents & APR_POLLOUT) {
+        FD_SET(fd, &(pollset->p->writeset));
+    }
+    if (descriptor->reqevents &
+        (APR_POLLPRI | APR_POLLERR | APR_POLLHUP | APR_POLLNVAL)) {
+        FD_SET(fd, &(pollset->p->exceptset));
+    }
+    if ((int) fd > pollset->p->maxfd) {
+        pollset->p->maxfd = (int) fd;
+    }
+    pollset->nelts++;
+    return APR_SUCCESS;
+}
+
+static apr_status_t impl_pollset_remove(apr_pollset_t * pollset,
+                                        const apr_pollfd_t * descriptor)
+{
+    apr_uint32_t i;
+    apr_os_sock_t fd;
+
+    if (descriptor->desc_type == APR_POLL_SOCKET) {
+        fd = descriptor->desc.s->socketdes;
+    }
+    else {
+#if !APR_FILES_AS_SOCKETS
+        return APR_EBADF;
+#else
+        fd = descriptor->desc.f->filedes;
+#endif
+    }
+
+    for (i = 0; i < pollset->nelts; i++) {
+        if (descriptor->desc.s == pollset->p->query_set[i].desc.s) {
+            /* Found an instance of the fd: remove this and any other copies */
+            apr_uint32_t dst = i;
+            apr_uint32_t old_nelts = pollset->nelts;
+            pollset->nelts--;
+            for (i++; i < old_nelts; i++) {
+                if (descriptor->desc.s == pollset->p->query_set[i].desc.s) {
+                    pollset->nelts--;
+                }
+                else {
+                    pollset->p->query_set[dst] = pollset->p->query_set[i];
+                    dst++;
+                }
+            }
+            FD_CLR(fd, &(pollset->p->readset));
+            FD_CLR(fd, &(pollset->p->writeset));
+            FD_CLR(fd, &(pollset->p->exceptset));
+            if (((int) fd == pollset->p->maxfd) && (pollset->p->maxfd > 0)) {
+                pollset->p->maxfd--;
+            }
+            return APR_SUCCESS;
+        }
+    }
+
+    return APR_NOTFOUND;
+}
+
+static apr_status_t impl_pollset_poll(apr_pollset_t *pollset,
+                                      apr_interval_time_t timeout,
+                                      apr_int32_t *num,
+                                      const apr_pollfd_t **descriptors)
+{
+    int rs;
+    apr_uint32_t i, j;
+    struct timeval tv, *tvptr;
+    fd_set readset, writeset, exceptset;
+    apr_status_t rv = APR_SUCCESS;
+
+    *num = 0;
+
+#ifdef WIN32
+    /* On Win32, select() must be presented with at least one socket to
+     * poll on, or select() will return WSAEINVAL.  So, we'll just
+     * short-circuit and bail now.
+     */
+    if (pollset->nelts == 0) {
+        if (timeout > 0) {
+            apr_sleep(timeout);
+            return APR_TIMEUP;
+        }
+        return APR_SUCCESS;
+    }
+#endif
+
+    if (timeout < 0) {
+        tvptr = NULL;
+    }
+    else {
+        tv.tv_sec = (long) apr_time_sec(timeout);
+        tv.tv_usec = (long) apr_time_usec(timeout);
+        tvptr = &tv;
+    }
+
+    memcpy(&readset, &(pollset->p->readset), sizeof(fd_set));
+    memcpy(&writeset, &(pollset->p->writeset), sizeof(fd_set));
+    memcpy(&exceptset, &(pollset->p->exceptset), sizeof(fd_set));
+
+#ifdef NETWARE
+    if (HAS_PIPES(pollset->p->set_type)) {
+        rs = pipe_select(pollset->p->maxfd + 1, &readset, &writeset, &exceptset,
+                         tvptr);
+    }
+    else
+#endif
+        rs = select(pollset->p->maxfd + 1, &readset, &writeset, &exceptset,
+                    tvptr);
+
+    if (rs < 0) {
+        return apr_get_netos_error();
+    }
+    if (rs == 0) {
+        return APR_TIMEUP;
+    }
+    j = 0;
+    for (i = 0; i < pollset->nelts; i++) {
+        apr_os_sock_t fd;
+        if (pollset->p->query_set[i].desc_type == APR_POLL_SOCKET) {
+            fd = pollset->p->query_set[i].desc.s->socketdes;
+        }
+        else {
+            if ((pollset->flags & APR_POLLSET_WAKEABLE) &&
+                pollset->p->query_set[i].desc.f == pollset->wakeup_pipe[0]) {
+                apr_poll_drain_wakeup_pipe(pollset->wakeup_pipe);
+                rv = APR_EINTR;
+                continue;
+            }
+            else {
+#if !APR_FILES_AS_SOCKETS
+                return APR_EBADF;
+#else
+                fd = pollset->p->query_set[i].desc.f->filedes;
+#endif
+            }
+        }
+        if (FD_ISSET(fd, &readset) || FD_ISSET(fd, &writeset) ||
+            FD_ISSET(fd, &exceptset)) {
+            pollset->p->result_set[j] = pollset->p->query_set[i];
+            pollset->p->result_set[j].rtnevents = 0;
+            if (FD_ISSET(fd, &readset)) {
+                pollset->p->result_set[j].rtnevents |= APR_POLLIN;
+            }
+            if (FD_ISSET(fd, &writeset)) {
+                pollset->p->result_set[j].rtnevents |= APR_POLLOUT;
+            }
+            if (FD_ISSET(fd, &exceptset)) {
+                pollset->p->result_set[j].rtnevents |= APR_POLLERR;
+            }
+            j++;
+        }
+    }
+    if (((*num) = j) != 0)
+        rv = APR_SUCCESS;
+
+    if (descriptors)
+        *descriptors = pollset->p->result_set;
+    return rv;
+}
+
+static const apr_pollset_provider_t impl = {
+    impl_pollset_create,
+    impl_pollset_add,
+    impl_pollset_remove,
+    impl_pollset_poll,
+    NULL,
+    "select"
+};
+
+const apr_pollset_provider_t *apr_pollset_provider_select = &impl;
diff --git a/poll/unix/wakeup.c b/poll/unix/wakeup.c
new file mode 100644
index 0000000..6c3dcd6
--- /dev/null
+++ b/poll/unix/wakeup.c
@@ -0,0 +1,152 @@
+/* Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "apr.h"
+#include "apr_poll.h"
+#include "apr_time.h"
+#include "apr_portable.h"
+#include "apr_arch_file_io.h"
+#include "apr_arch_networkio.h"
+#include "apr_arch_poll_private.h"
+#include "apr_arch_inherit.h"
+
+#if !APR_FILES_AS_SOCKETS
+
+#ifdef WIN32
+
+apr_status_t apr_poll_create_wakeup_pipe(apr_pool_t *pool, apr_pollfd_t *pfd,
+                                         apr_file_t **wakeup_pipe)
+{
+    apr_status_t rv;
+
+    if ((rv = apr_file_socket_pipe_create(&wakeup_pipe[0], &wakeup_pipe[1],
+                                      pool)) != APR_SUCCESS)
+        return rv;
+
+    pfd->reqevents = APR_POLLIN;
+    pfd->desc_type = APR_POLL_FILE;
+    pfd->desc.f = wakeup_pipe[0];
+    return APR_SUCCESS;
+}
+
+apr_status_t apr_poll_close_wakeup_pipe(apr_file_t **wakeup_pipe)
+{
+    apr_status_t rv0 = APR_SUCCESS;
+    apr_status_t rv1 = APR_SUCCESS;
+
+    /* Close both sides of the wakeup pipe */
+    if (wakeup_pipe[0]) {
+        rv0 = apr_file_socket_pipe_close(wakeup_pipe[0]);
+        wakeup_pipe[0] = NULL;
+    }
+    if (wakeup_pipe[1]) {
+        rv1 = apr_file_socket_pipe_close(wakeup_pipe[1]);
+        wakeup_pipe[1] = NULL;
+    }
+    return rv0 ? rv0 : rv1;
+}
+
+#else /* !WIN32 */
+
+apr_status_t apr_poll_create_wakeup_pipe(apr_pollfd_t *pfd, apr_file_t **wakeup_pipe)
+{
+    return APR_ENOTIMPL;
+}
+
+apr_status_t apr_poll_close_wakeup_pipe(apr_file_t **wakeup_pipe)
+{
+    return APR_ENOTIMPL;
+}
+
+#endif /* !WIN32 */
+
+#else  /* APR_FILES_AS_SOCKETS */
+
+apr_status_t apr_poll_create_wakeup_pipe(apr_pool_t *pool, apr_pollfd_t *pfd,
+                                         apr_file_t **wakeup_pipe)
+{
+    apr_status_t rv;
+
+    if ((rv = apr_file_pipe_create_ex(&wakeup_pipe[0], &wakeup_pipe[1],
+                                      APR_WRITE_BLOCK,
+                                      pool)) != APR_SUCCESS)
+        return rv;
+
+    pfd->p = pool;
+    pfd->reqevents = APR_POLLIN;
+    pfd->desc_type = APR_POLL_FILE;
+    pfd->desc.f = wakeup_pipe[0];
+
+    {
+        int flags;
+
+        if ((flags = fcntl(wakeup_pipe[0]->filedes, F_GETFD)) == -1)
+            return errno;
+
+        flags |= FD_CLOEXEC;
+        if (fcntl(wakeup_pipe[0]->filedes, F_SETFD, flags) == -1)
+            return errno;
+    }
+    {
+        int flags;
+
+        if ((flags = fcntl(wakeup_pipe[1]->filedes, F_GETFD)) == -1)
+            return errno;
+
+        flags |= FD_CLOEXEC;
+        if (fcntl(wakeup_pipe[1]->filedes, F_SETFD, flags) == -1)
+            return errno;
+    }
+
+    return APR_SUCCESS;
+}
+
+apr_status_t apr_poll_close_wakeup_pipe(apr_file_t **wakeup_pipe)
+{
+    apr_status_t rv0 = APR_SUCCESS;
+    apr_status_t rv1 = APR_SUCCESS;
+
+    /* Close both sides of the wakeup pipe */
+    if (wakeup_pipe[0]) {
+        rv0 = apr_file_close(wakeup_pipe[0]);
+        wakeup_pipe[0] = NULL;
+    }
+    if (wakeup_pipe[1]) {
+        rv1 = apr_file_close(wakeup_pipe[1]);
+        wakeup_pipe[1] = NULL;
+    }
+    return rv0 ? rv0 : rv1;
+}
+
+#endif /* APR_FILES_AS_SOCKETS */
+
+/* Read and discard whatever is in the wakeup pipe.
+ */
+void apr_poll_drain_wakeup_pipe(apr_file_t **wakeup_pipe)
+{
+    char rb[512];
+    apr_size_t nr = sizeof(rb);
+
+    while (apr_file_read(wakeup_pipe[0], rb, &nr) == APR_SUCCESS) {
+        /* Although we write just one byte to the other end of the pipe
+         * during wakeup, multiple threads could call the wakeup.
+         * So simply drain out from the input side of the pipe all
+         * the data.
+         */
+        if (nr != sizeof(rb))
+            break;
+    }
+}
diff --git a/poll/unix/z_asio.c b/poll/unix/z_asio.c
new file mode 100644
index 0000000..48b531c
--- /dev/null
+++ b/poll/unix/z_asio.c
@@ -0,0 +1,782 @@
+/* Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ *
+ ******************************************************************************
+ *
+ * This implementation is based on a design by John Brooks (IBM Pok) which uses
+ * the z/OS sockets async i/o facility.  When a
+ * socket is added to the pollset, an async poll is issued for that individual
+ * socket.  It specifies that the kernel should send an IPC message when the
+ * socket becomes ready.  The IPC messages are sent to a single message queue
+ * that is part of the pollset.  apr_pollset_poll waits on the arrival of IPC
+ * messages or the specified timeout.
+ *
+ * Since z/OS does not support async i/o for pipes or files at present, this
+ * implementation falls back to using ordinary poll() when
+ * APR_POLLSET_THREADSAFE is unset.
+ *
+ * Greg Ames
+ * April 2012
+ */
+
+#include "apr.h"
+#include "apr_hash.h"
+#include "apr_poll.h"
+#include "apr_time.h"
+#include "apr_portable.h"
+#include "apr_arch_inherit.h"
+#include "apr_arch_file_io.h"
+#include "apr_arch_networkio.h"
+#include "apr_arch_poll_private.h"
+
+#ifdef HAVE_AIO_MSGQ
+
+#include <sys/msg.h>  	/* msgget etc   */
+#include <time.h>     	/* timestruct   */
+#include <poll.h>     	/* pollfd       */
+#include <limits.h>     /* MAX_INT      */
+
+struct apr_pollset_private_t
+{
+    int             msg_q;              /* IPC message queue. The z/OS kernel sends messages
+                                         * to this queue when our async polls on individual
+                                         * file descriptors complete
+                                         */
+    apr_pollfd_t    *result_set;
+    apr_uint32_t    size;
+
+#if APR_HAS_THREADS
+    /* A thread mutex to protect operations on the rings and the hash */
+    apr_thread_mutex_t *ring_lock;
+#endif
+
+    /* A hash of all active elements used for O(1) _remove operations */
+    apr_hash_t      *elems;
+
+    APR_RING_HEAD(ready_ring_t,       asio_elem_t)      ready_ring;
+    APR_RING_HEAD(prior_ready_ring_t, asio_elem_t)      prior_ready_ring;
+    APR_RING_HEAD(free_ring_t,        asio_elem_t)      free_ring;
+
+    /* for pipes etc with no asio */
+    struct pollfd   *pollset;
+    apr_pollfd_t    *query_set;
+};
+
+typedef enum {
+    ASIO_INIT = 0,
+    ASIO_REMOVED,
+    ASIO_COMPLETE
+} asio_state_e;
+
+typedef struct asio_elem_t asio_elem_t;
+
+struct asio_msgbuf_t {
+    long         msg_type;       /* must be > 0 */
+    asio_elem_t *msg_elem;
+};
+
+struct asio_elem_t
+{
+    APR_RING_ENTRY(asio_elem_t) link;
+    apr_pollfd_t                pfd;
+    struct pollfd               os_pfd;
+    struct aiocb                a;
+    asio_state_e                state;
+    struct asio_msgbuf_t        msg;
+};
+
+#define DEBUG 0
+
+/* DEBUG settings: 0 - no debug messages at all,
+ *                 1 - should not occur messages,
+ *                 2 - apr_pollset_* entry and exit messages,
+ *                 3 - state changes, memory usage,
+ *                 4 - z/OS, APR, and internal calls,
+ *                 5 - everything else except the timer pop path,
+ *                 6 - everything, including the Event 1 sec timer pop path
+ *
+ *  each DEBUG level includes all messages produced by lower numbered levels
+ */
+
+#if DEBUG
+
+#include <assert.h>
+#include <unistd.h>	/* getpid       */
+
+#define DBG_BUFF char dbg_msg_buff[256];
+
+#define DBG_TEST(lvl) if (lvl <= DEBUG) {
+
+#define DBG_CORE(msg)               sprintf(dbg_msg_buff, "% 8d " __FUNCTION__ \
+                                        " "  msg, getpid()),                   \
+                                    fprintf(stderr, "%s", dbg_msg_buff);
+#define DBG_CORE1(msg, var1)        sprintf(dbg_msg_buff, "% 8d " __FUNCTION__ \
+                                        " " msg, getpid(), var1),              \
+                                    fprintf(stderr, "%s", dbg_msg_buff);
+#define DBG_CORE2(msg, var1, var2)  sprintf(dbg_msg_buff, "% 8d " __FUNCTION__ \
+                                        " " msg, getpid(), var1, var2),        \
+                                    fprintf(stderr, "%s", dbg_msg_buff);
+#define DBG_CORE3(msg, var1, var2, var3)                                       \
+                                    sprintf(dbg_msg_buff, "% 8d " __FUNCTION__ \
+                                        " " msg, getpid(), var1, var2, var3),  \
+                                    fprintf(stderr, "%s", dbg_msg_buff);
+#define DBG_CORE4(msg, var1, var2, var3, var4)                                 \
+                                    sprintf(dbg_msg_buff, "% 8d " __FUNCTION__ \
+                                        " " msg, getpid(), var1, var2, var3, var4),\
+                                    fprintf(stderr, "%s", dbg_msg_buff);
+
+#define DBG_END }
+
+#define DBG(lvl, msg)   DBG_TEST(lvl)   \
+                        DBG_CORE(msg)   \
+                        DBG_END
+
+#define DBG1(lvl, msg, var1)    DBG_TEST(lvl)           \
+                                DBG_CORE1(msg, var1)    \
+                                DBG_END
+
+#define DBG2(lvl, msg, var1, var2)      DBG_TEST(lvl)               \
+                                        DBG_CORE2(msg, var1, var2)  \
+                                        DBG_END
+
+#define DBG3(lvl, msg, var1, var2, var3)                        \
+                        DBG_TEST(lvl)                           \
+                        DBG_CORE3(msg, var1, var2, var3)        \
+                        DBG_END
+
+#define DBG4(lvl, msg, var1, var2, var3, var4)                  \
+                        DBG_TEST(lvl)                           \
+                        DBG_CORE4(msg, var1, var2, var3, var4)  \
+                        DBG_END
+
+#else  /* DEBUG is 0 */
+#define DBG_BUFF
+#define DBG(lvl, msg)                            ((void)0)
+#define DBG1(lvl, msg, var1)                     ((void)0)
+#define DBG2(lvl, msg, var1, var2)               ((void)0)
+#define DBG3(lvl, msg, var1, var2, var3)         ((void)0)
+#define DBG4(lvl, msg, var1, var2, var3, var4)   ((void)0)
+
+#endif /* DEBUG */
+
+static int asyncio(struct aiocb *a)
+{
+    DBG_BUFF
+    int rv;
+
+#ifdef _LP64
+#define AIO BPX4AIO
+#else
+#define AIO BPX1AIO
+#endif
+
+    AIO(sizeof(struct aiocb), a, &rv, &errno, __err2ad());
+    DBG2(4, "BPX4AIO aiocb %p rv %d\n",
+             a, rv);
+#ifdef DEBUG
+    if (rv < 0) {
+        DBG2(4, "errno %d errnojr %08x\n",
+                 errno, *__err2ad());
+    }
+#endif
+    return rv;
+}
+
+static apr_int16_t get_event(apr_int16_t event)
+{
+    DBG_BUFF
+    apr_int16_t rv = 0;
+    DBG(4, "entered\n");
+
+    if (event & APR_POLLIN)
+        rv |= POLLIN;
+    if (event & APR_POLLPRI)
+        rv |= POLLPRI;
+    if (event & APR_POLLOUT)
+        rv |= POLLOUT;
+    if (event & APR_POLLERR)
+        rv |= POLLERR;
+    if (event & APR_POLLHUP)
+        rv |= POLLHUP;
+    if (event & APR_POLLNVAL)
+        rv |= POLLNVAL;
+
+    DBG(4, "exiting\n");
+    return rv;
+}
+
+static apr_int16_t get_revent(apr_int16_t event)
+{
+    DBG_BUFF
+    apr_int16_t rv = 0;
+    DBG(4, "entered\n");
+
+    if (event & POLLIN)
+        rv |= APR_POLLIN;
+    if (event & POLLPRI)
+        rv |= APR_POLLPRI;
+    if (event & POLLOUT)
+        rv |= APR_POLLOUT;
+    if (event & POLLERR)
+        rv |= APR_POLLERR;
+    if (event & POLLHUP)
+        rv |= APR_POLLHUP;
+    if (event & POLLNVAL)
+        rv |= APR_POLLNVAL;
+
+    DBG(4, "exiting\n");
+    return rv;
+}
+
+static apr_status_t asio_pollset_cleanup(apr_pollset_t *pollset)
+{
+    DBG_BUFF
+    int rv;
+
+    DBG(4, "entered\n");
+    if (pollset->flags & APR_POLLSET_THREADSAFE) { 
+        rv = msgctl(pollset->p->msg_q, IPC_RMID, NULL);
+        DBG1(4, "asio_pollset_cleanup: msgctl(IPC_RMID) returned %d\n", rv);
+    }
+
+    return rv;
+}
+
+static apr_status_t asio_pollset_create(apr_pollset_t *pollset,
+                                        apr_uint32_t size,
+                                        apr_pool_t *p,
+                                        apr_uint32_t flags)
+{
+    DBG_BUFF
+    apr_status_t rv;
+    apr_pollset_private_t *priv;
+
+    DBG1(2, "entered, flags: %x\n", flags);
+
+    priv = pollset->p = apr_pcalloc(p, sizeof(*priv));
+
+    if (flags & APR_POLLSET_THREADSAFE) {
+#if APR_HAS_THREADS
+        if ((rv = apr_thread_mutex_create(&(priv->ring_lock),
+                                           APR_THREAD_MUTEX_DEFAULT,
+                                           p)) != APR_SUCCESS) {
+            DBG1(1, "apr_thread_mutex_create returned %d\n", rv);
+            pollset->p = NULL;
+            return rv;
+        }
+        rv = msgget(IPC_PRIVATE, S_IWUSR+S_IRUSR); /* user r/w perms */
+        if (rv < 0) {
+#if DEBUG
+            perror(__FUNCTION__ " msgget returned < 0 ");
+#endif
+            pollset->p = NULL;
+            return rv;
+        }
+
+        DBG2(4, "pollset %p msgget was OK, rv=%d\n", pollset, rv);
+        priv->msg_q = rv;
+        priv->elems   = apr_hash_make(p);
+
+        APR_RING_INIT(&priv->free_ring, asio_elem_t, link);
+        APR_RING_INIT(&priv->prior_ready_ring, asio_elem_t, link);
+
+#else  /* APR doesn't have threads but caller wants a threadsafe pollset */
+        pollset->p = NULL;
+        return APR_ENOTIMPL;
+#endif
+
+    } else {  /* APR_POLLSET_THREADSAFE not set, i.e. no async i/o,
+               * init fields only needed in old style pollset
+               */
+
+        priv->pollset = apr_palloc(p, size * sizeof(struct pollfd));
+        priv->query_set = apr_palloc(p, size * sizeof(apr_pollfd_t));
+
+        if ((!priv->pollset) || (!priv->query_set)) {
+            pollset->p = NULL;
+            return APR_ENOMEM;
+        }
+    }
+
+    pollset->nelts   = 0;
+    pollset->flags   = flags;
+    pollset->pool    = p;
+    priv->size    = size;
+    priv->result_set = apr_palloc(p, size * sizeof(apr_pollfd_t));
+    if (!priv->result_set) {
+        if (flags & APR_POLLSET_THREADSAFE) {
+            msgctl(priv->msg_q, IPC_RMID, NULL);
+        }
+        pollset->p = NULL;
+        return APR_ENOMEM;
+    }
+
+    DBG2(2, "exiting, pollset: %p, type: %s\n",
+             pollset,
+             flags & APR_POLLSET_THREADSAFE ? "async" : "POSIX");
+
+
+    return APR_SUCCESS;
+
+} /* end of asio_pollset_create */
+
+static apr_status_t posix_add(apr_pollset_t      *pollset,
+                              const apr_pollfd_t *descriptor)
+{
+    DBG_BUFF
+    int fd;
+    apr_pool_t  *p = pollset->pool;
+    apr_pollset_private_t *priv = pollset->p;
+
+    DBG(4, "entered\n");
+
+    if (pollset->nelts == priv->size) {
+        return APR_ENOMEM;
+    }
+
+    priv->query_set[pollset->nelts] = *descriptor;
+    if (descriptor->desc_type == APR_POLL_SOCKET) {
+        fd = descriptor->desc.s->socketdes;
+    }
+    else {
+        fd = descriptor->desc.f->filedes;
+    }
+
+    priv->pollset[pollset->nelts].fd = fd;
+
+    priv->pollset[pollset->nelts].events =
+        get_event(descriptor->reqevents);
+
+    pollset->nelts++;
+
+    DBG2(4, "exiting, fd %d added to pollset %p\n", fd, pollset);
+
+    return APR_SUCCESS;
+}   /* end of posix_add */
+
+
+static apr_status_t asio_pollset_add(apr_pollset_t *pollset,
+                                     const apr_pollfd_t *descriptor)
+{
+    DBG_BUFF
+    asio_elem_t *elem;
+    apr_status_t rv = APR_SUCCESS;
+    apr_pollset_private_t *priv = pollset->p;
+
+    pollset_lock_rings();
+    DBG(2, "entered\n");
+
+    if (pollset->flags & APR_POLLSET_THREADSAFE) {
+
+        if (!APR_RING_EMPTY(&(priv->free_ring), asio_elem_t, link)) {
+            elem = APR_RING_FIRST(&(priv->free_ring));
+            APR_RING_REMOVE(elem, link);
+            DBG1(3, "used recycled memory at %08p\n", elem);
+            elem->state = ASIO_INIT;
+            elem->a.aio_cflags = 0;
+        }
+        else {
+            elem = (asio_elem_t *) apr_pcalloc(pollset->pool, sizeof(asio_elem_t));
+            DBG1(3, "alloced new memory at %08p\n", elem);
+
+            elem->a.aio_notifytype = AIO_MSGQ;
+            elem->a.aio_msgev_qid  = priv->msg_q;
+            DBG1(5, "aio_msgev_quid = %d \n", elem->a.aio_msgev_qid);
+            elem->a.aio_msgev_size = sizeof(asio_elem_t *);
+            elem->a.aio_msgev_flag = 0;     /* wait if queue is full */
+            elem->a.aio_msgev_addr = &(elem->msg);
+            elem->a.aio_buf        = &(elem->os_pfd);
+            elem->a.aio_nbytes     = 1;     /* number of pfds to poll */
+            elem->msg.msg_type     = 1;
+            elem->msg.msg_elem     = elem;
+        }
+
+        /* z/OS only supports async I/O for sockets for now */
+        elem->os_pfd.fd = descriptor->desc.s->socketdes;
+
+        APR_RING_ELEM_INIT(elem, link);
+        elem->a.aio_cmd       = AIO_SELPOLL;
+        elem->a.aio_cflags    &= ~AIO_OK2COMPIMD; /* not OK to complete inline*/
+        elem->pfd             = *descriptor;
+        elem->os_pfd.events   = get_event(descriptor->reqevents);
+
+        if (0 != asyncio(&elem->a)) {
+            rv = errno;
+            DBG3(4, "pollset %p asio failed fd %d, errno %p\n",
+                     pollset, elem->os_pfd.fd, rv);
+#if DEBUG
+            perror(__FUNCTION__ " asio failure");
+#endif
+        }
+        else {
+            DBG2(4, "good asio call, adding fd %d to pollset %p\n",
+                     elem->os_pfd.fd, pollset);
+
+            pollset->nelts++;
+            apr_hash_set(priv->elems, &(elem->os_pfd.fd), sizeof(int), elem);
+        }
+    }
+    else {
+        /* APR_POLLSET_THREADSAFE isn't set.  use POSIX poll in case
+         * pipes or files are used with this pollset
+         */
+
+        rv = posix_add(pollset, descriptor);
+    }
+
+    DBG1(2, "exiting, rv = %d\n", rv);
+
+    pollset_unlock_rings();
+    return rv;
+} /* end of asio_pollset_add */
+
+static posix_remove(apr_pollset_t *pollset, const apr_pollfd_t *descriptor)
+{
+    DBG_BUFF
+    apr_uint32_t i;
+    apr_pollset_private_t *priv = pollset->p;
+
+    DBG(4, "entered\n");
+    for (i = 0; i < pollset->nelts; i++) {
+        if (descriptor->desc.s == priv->query_set[i].desc.s) {
+            /* Found an instance of the fd: remove this and any other copies */
+            apr_uint32_t dst = i;
+            apr_uint32_t old_nelts = pollset->nelts;
+            pollset->nelts--;
+            for (i++; i < old_nelts; i++) {
+                if (descriptor->desc.s == priv->query_set[i].desc.s) {
+                    pollset->nelts--;
+                }
+                else {
+                    priv->pollset[dst] = priv->pollset[i];
+                    priv->query_set[dst] = priv->query_set[i];
+                    dst++;
+                }
+            }
+            DBG(4, "returning OK\n");
+            return APR_SUCCESS;
+        }
+    }
+
+    DBG(1, "returning APR_NOTFOUND\n");
+    return APR_NOTFOUND;
+
+}   /* end of posix_remove */
+
+static apr_status_t asio_pollset_remove(apr_pollset_t *pollset,
+                                        const apr_pollfd_t *descriptor)
+{
+    DBG_BUFF
+    asio_elem_t *elem;
+    apr_status_t rv = APR_SUCCESS;
+    apr_pollset_private_t *priv = pollset->p;
+    /* AIO_CANCEL is synchronous, so autodata works fine.  */
+    struct aiocb cancel_a = {0};   
+
+    int fd;
+
+    DBG(2, "entered\n");
+
+    if (!(pollset->flags & APR_POLLSET_THREADSAFE)) {
+        return posix_remove(pollset, descriptor);
+    }
+
+    pollset_lock_rings();
+
+#if DEBUG
+    assert(descriptor->desc_type == APR_POLL_SOCKET);
+#endif
+    /* zOS 1.12 doesn't support files for async i/o */
+    fd = descriptor->desc.s->socketdes;
+
+    elem = apr_hash_get(priv->elems, &(fd), sizeof(int));
+    if (elem == NULL) {
+        DBG1(1, "couldn't find fd %d\n", fd);
+        rv = APR_NOTFOUND;
+    } else {
+        DBG1(5, "hash found fd %d\n", fd);
+        /* delete this fd from the hash */
+        apr_hash_set(priv->elems, &(fd), sizeof(int), NULL);
+
+        if (elem->state == ASIO_INIT) {
+            /* asyncio call to cancel */
+            cancel_a.aio_cmd = AIO_CANCEL;
+            cancel_a.aio_buf = &elem->a;   /* point to original aiocb */
+
+            cancel_a.aio_cflags  = 0;
+            cancel_a.aio_cflags2 = 0;
+
+            /* we want the original aiocb to show up on the pollset message queue 
+             * before recycling its memory to eliminate race conditions
+             */
+
+            rv = asyncio(&cancel_a);
+            DBG1(4, "asyncio returned %d\n", rv);
+
+#if DEBUG
+            assert(rv == 1);
+#endif
+        }
+        elem->state = ASIO_REMOVED;
+        rv = APR_SUCCESS;
+    }
+
+    DBG1(2, "exiting, rv: %d\n", rv);
+
+    pollset_unlock_rings();
+
+    return rv;
+}   /* end of asio_pollset_remove */
+
+static posix_poll(apr_pollset_t *pollset,
+                  apr_interval_time_t timeout,
+                  apr_int32_t *num,
+                  const apr_pollfd_t **descriptors)
+{
+    DBG_BUFF
+    int rv;
+    apr_uint32_t i, j;
+    apr_pollset_private_t *priv = pollset->p;
+
+    DBG(4, "entered\n");
+
+    if (timeout > 0) {
+        timeout /= 1000;
+    }
+    rv = poll(priv->pollset, pollset->nelts, timeout);
+    (*num) = rv;
+    if (rv < 0) {
+        return apr_get_netos_error();
+    }
+    if (rv == 0) {
+        return APR_TIMEUP;
+    }
+    j = 0;
+    for (i = 0; i < pollset->nelts; i++) {
+        if (priv->pollset[i].revents != 0) {
+            priv->result_set[j] = priv->query_set[i];
+            priv->result_set[j].rtnevents =
+                get_revent(priv->pollset[i].revents);
+            j++;
+        }
+    }
+    if (descriptors)
+        *descriptors = priv->result_set;
+
+    DBG(4, "exiting ok\n");
+    return APR_SUCCESS;
+
+}   /* end of posix_poll */
+
+static process_msg(apr_pollset_t *pollset, struct asio_msgbuf_t *msg)
+{
+    DBG_BUFF
+    asio_elem_t *elem = msg->msg_elem;
+
+    switch(elem->state) {
+    case ASIO_REMOVED:
+        DBG2(5, "for cancelled elem, recycling memory - elem %08p, fd %d\n",
+                elem, elem->os_pfd.fd);
+        APR_RING_INSERT_TAIL(&(pollset->p->free_ring), elem,
+                             asio_elem_t, link);
+        break;
+    case ASIO_INIT:
+        DBG2(4, "adding to ready ring: elem %08p, fd %d\n",
+                elem, elem->os_pfd.fd);
+        elem->state = ASIO_COMPLETE;
+        APR_RING_INSERT_TAIL(&(pollset->p->ready_ring), elem,
+                             asio_elem_t, link);
+        break;
+    default:
+        DBG3(1, "unexpected state: elem %08p, fd %d, state %d\n",
+            elem, elem->os_pfd.fd, elem->state);
+#if DEBUG
+        assert(0);
+#endif
+    }
+}
+
+static apr_status_t asio_pollset_poll(apr_pollset_t *pollset,
+                                      apr_interval_time_t timeout,
+                                      apr_int32_t *num,
+                                      const apr_pollfd_t **descriptors)
+{
+    DBG_BUFF
+    int i, ret;
+    asio_elem_t *elem, *next_elem;
+    struct asio_msgbuf_t msg_buff;
+    struct timespec tv;
+    apr_status_t rv = APR_SUCCESS;
+    apr_pollset_private_t *priv = pollset->p;
+
+    DBG(6, "entered\n"); /* chatty - traces every second w/Event */
+
+    if ((pollset->flags & APR_POLLSET_THREADSAFE) == 0 ) {
+        return posix_poll(pollset, timeout, num, descriptors);
+    }
+
+    pollset_lock_rings();
+    APR_RING_INIT(&(priv->ready_ring), asio_elem_t, link);
+
+    while (!APR_RING_EMPTY(&(priv->prior_ready_ring), asio_elem_t, link)) {
+        elem = APR_RING_FIRST(&(priv->prior_ready_ring));
+        DBG3(5, "pollset %p elem %p fd %d on prior ready ring\n",
+                pollset,
+                elem,
+                elem->os_pfd.fd);
+
+        APR_RING_REMOVE(elem, link);
+
+        /*
+         * since USS does not remember what's in our pollset, we have
+         * to re-add fds which have not been apr_pollset_remove'd
+         *
+         * there may have been too many ready fd's to return in the
+         * result set last time. re-poll inline for both cases
+         */
+
+        if (elem->state == ASIO_REMOVED) {
+
+            /* 
+             * async i/o is done since it was found on prior_ready
+             * the state says the caller is done with it too 
+             * so recycle the elem 
+             */
+             
+            APR_RING_INSERT_TAIL(&(priv->free_ring), elem,
+                                 asio_elem_t, link);
+            continue;  /* do not re-add if it has been _removed */
+        }
+
+        elem->state = ASIO_INIT;
+        elem->a.aio_cflags     = AIO_OK2COMPIMD;
+
+        if (0 != (ret = asyncio(&elem->a))) {
+            if (ret == 1) {
+                DBG(4, "asyncio() completed inline\n");
+                /* it's ready now */
+                elem->state = ASIO_COMPLETE;
+                APR_RING_INSERT_TAIL(&(priv->ready_ring), elem, asio_elem_t,
+                                     link);
+            }
+            else {
+                DBG2(1, "asyncio() failed, ret: %d, errno: %d\n",
+                        ret, errno);
+                pollset_unlock_rings();
+                return errno;
+            }
+        }
+        DBG1(4, "asyncio() completed rc %d\n", ret);
+    }
+
+    DBG(6, "after prior ready loop\n"); /* chatty w/timeouts, hence 6 */
+
+    /* Gather async poll completions that have occurred since the last call */
+    while (0 < msgrcv(priv->msg_q, &msg_buff, sizeof(asio_elem_t *), 0,
+                      IPC_NOWAIT)) {
+        process_msg(pollset, &msg_buff);
+    }
+
+    /* Suspend if nothing is ready yet. */
+    if (APR_RING_EMPTY(&(priv->ready_ring), asio_elem_t, link)) {
+
+        if (timeout >= 0) {
+            tv.tv_sec  = apr_time_sec(timeout);
+            tv.tv_nsec = apr_time_usec(timeout) * 1000;
+        } else {
+            tv.tv_sec = INT_MAX;  /* block until something is ready */
+        }
+
+        DBG2(6, "nothing on the ready ring "
+                "- blocking for %d seconds %d ns\n",
+                tv.tv_sec, tv.tv_nsec);
+
+        pollset_unlock_rings();   /* allow other apr_pollset_* calls while blocked */
+
+        if (0 >= (ret = __msgrcv_timed(priv->msg_q, &msg_buff,
+                                       sizeof(asio_elem_t *), 0, NULL, &tv))) {
+#if DEBUG
+            if (errno == EAGAIN) {
+                DBG(6, "__msgrcv_timed timed out\n"); /* timeout path, so 6 */
+            }
+            else {
+                DBG(1, "__msgrcv_timed failed!\n");
+            }
+#endif
+            return (errno == EAGAIN) ? APR_TIMEUP : errno;
+        }
+
+        pollset_lock_rings();
+
+        process_msg(pollset, &msg_buff);
+    }
+
+    APR_RING_INIT(&priv->prior_ready_ring, asio_elem_t, link);
+
+    (*num) = 0;
+    elem = APR_RING_FIRST(&(priv->ready_ring));
+
+    for (i = 0;
+
+        i < priv->size
+                && elem != APR_RING_SENTINEL(&(priv->ready_ring), asio_elem_t, link);
+        i++) {
+             DBG2(5, "ready ring: elem %08p, fd %d\n", elem, elem->os_pfd.fd);
+
+             priv->result_set[i] = elem->pfd;
+             priv->result_set[i].rtnevents
+                                    = get_revent(elem->os_pfd.revents);
+             (*num)++;
+
+             elem = APR_RING_NEXT(elem, link);
+
+#if DEBUG
+             if (elem == APR_RING_SENTINEL(&(priv->ready_ring), asio_elem_t, link)) {
+                 DBG(5, "end of ready ring reached\n");
+             }
+#endif
+    }
+
+    if (descriptors) {
+        *descriptors = priv->result_set;
+    }
+
+    /* if the result size is too small, remember which descriptors
+     * haven't had results reported yet.  we will look
+     * at these descriptors on the next apr_pollset_poll call
+     */
+
+    APR_RING_CONCAT(&priv->prior_ready_ring, &(priv->ready_ring), asio_elem_t, link);
+
+    DBG1(2, "exiting, rv = %d\n", rv);
+
+    pollset_unlock_rings();
+
+    return rv;
+}  /* end of asio_pollset_poll */
+
+static const apr_pollset_provider_t impl = {
+    asio_pollset_create,
+    asio_pollset_add,
+    asio_pollset_remove,
+    asio_pollset_poll,
+    asio_pollset_cleanup,
+    "asio"
+};
+
+const apr_pollset_provider_t *apr_pollset_provider_aio_msgq = &impl;
+
+#endif /* HAVE_AIO_MSGQ */