Upstream tarball 2.2.3upstream/2.2.3

9 files changed, 3279 insertions, 0 deletions

diff --git a/server/mpm/experimental/event/Makefile.in b/server/mpm/experimental/event/Makefile.in
new file mode 100644
index 00000000..7c2a1a7a
--- /dev/null
+++ b/server/mpm/experimental/event/Makefile.in
@@ -0,0 +1,5 @@
+
+LTLIBRARY_NAME    = libevent.la
+LTLIBRARY_SOURCES = event.c fdqueue.c pod.c
+
+include $(top_srcdir)/build/ltlib.mk
diff --git a/server/mpm/experimental/event/config5.m4 b/server/mpm/experimental/event/config5.m4
new file mode 100644
index 00000000..5e1db539
--- /dev/null
+++ b/server/mpm/experimental/event/config5.m4
@@ -0,0 +1,6 @@
+dnl ## XXX - Need a more thorough check of the proper flags to use
+
+if test "$MPM_NAME" = "event" ; then
+    AC_CHECK_FUNCS(pthread_kill)
+    APACHE_FAST_OUTPUT(server/mpm/$MPM_SUBDIR_NAME/Makefile)
+fi
diff --git a/server/mpm/experimental/event/event.c b/server/mpm/experimental/event/event.c
new file mode 100644
index 00000000..c47e857d
--- /dev/null
+++ b/server/mpm/experimental/event/event.c
@@ -0,0 +1,2456 @@
+/* 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 MPM tries to fix the 'keep alive problem' in HTTP.
+ *
+ * After a client completes the first request, the client can keep the
+ * connection open to send more requests with the same socket.  This can save
+ * signifigant overhead in creating TCP connections.  However, the major
+ * disadvantage is that Apache traditionally keeps an entire child
+ * process/thread waiting for data from the client.  To solve this problem,
+ * this MPM has a dedicated thread for handling both the Listenting sockets,
+ * and all sockets that are in a Keep Alive status.
+ *
+ * The MPM assumes the underlying apr_pollset implmentation is somewhat
+ * threadsafe.  This currently is only compatible with KQueue and EPoll.  This
+ * enables the MPM to avoid extra high level locking or having to wake up the
+ * listener thread when a keep-alive socket needs to be sent to it.
+ *
+ * This MPM not preform well on older platforms that do not have very good
+ * threading, like Linux with a 2.4 kernel, but this does not matter, since we
+ * require EPoll or KQueue.
+ *
+ * For FreeBSD, use 5.3.  It is possible to run this MPM on FreeBSD 5.2.1, if
+ * you use libkse (see `man libmap.conf`).
+ *
+ * For NetBSD, use at least 2.0.
+ *
+ * For Linux, you should use a 2.6 kernel, and make sure your glibc has epoll
+ * support compiled in.
+ *
+ */
+
+#include "apr.h"
+#include "apr_portable.h"
+#include "apr_strings.h"
+#include "apr_file_io.h"
+#include "apr_thread_proc.h"
+#include "apr_signal.h"
+#include "apr_thread_mutex.h"
+#include "apr_proc_mutex.h"
+#include "apr_poll.h"
+#include "apr_ring.h"
+#include "apr_queue.h"
+#define APR_WANT_STRFUNC
+#include "apr_want.h"
+
+#if APR_HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+#if APR_HAVE_SYS_SOCKET_H
+#include <sys/socket.h>
+#endif
+#if APR_HAVE_SYS_WAIT_H
+#include <sys/wait.h>
+#endif
+#ifdef HAVE_SYS_PROCESSOR_H
+#include <sys/processor.h>      /* for bindprocessor() */
+#endif
+
+#if !APR_HAS_THREADS
+#error The Event MPM requires APR threads, but they are unavailable.
+#endif
+
+#define CORE_PRIVATE
+
+#include "ap_config.h"
+#include "httpd.h"
+#include "http_main.h"
+#include "http_log.h"
+#include "http_config.h"        /* for read_config */
+#include "http_core.h"          /* for get_remote_host */
+#include "http_connection.h"
+#include "ap_mpm.h"
+#include "pod.h"
+#include "mpm_common.h"
+#include "ap_listen.h"
+#include "scoreboard.h"
+#include "fdqueue.h"
+#include "mpm_default.h"
+#include "http_vhost.h"
+
+#include <signal.h>
+#include <limits.h>             /* for INT_MAX */
+
+/* Limit on the total --- clients will be locked out if more servers than
+ * this are needed.  It is intended solely to keep the server from crashing
+ * when things get out of hand.
+ *
+ * We keep a hard maximum number of servers, for two reasons --- first off,
+ * in case something goes seriously wrong, we want to stop the fork bomb
+ * short of actually crashing the machine we're running on by filling some
+ * kernel table.  Secondly, it keeps the size of the scoreboard file small
+ * enough that we can read the whole thing without worrying too much about
+ * the overhead.
+ */
+#ifndef DEFAULT_SERVER_LIMIT
+#define DEFAULT_SERVER_LIMIT 16
+#endif
+
+/* Admin can't tune ServerLimit beyond MAX_SERVER_LIMIT.  We want
+ * some sort of compile-time limit to help catch typos.
+ */
+#ifndef MAX_SERVER_LIMIT
+#define MAX_SERVER_LIMIT 20000
+#endif
+
+/* Limit on the threads per process.  Clients will be locked out if more than
+ * this are needed.
+ *
+ * We keep this for one reason it keeps the size of the scoreboard file small
+ * enough that we can read the whole thing without worrying too much about
+ * the overhead.
+ */
+#ifndef DEFAULT_THREAD_LIMIT
+#define DEFAULT_THREAD_LIMIT 64
+#endif
+
+/* Admin can't tune ThreadLimit beyond MAX_THREAD_LIMIT.  We want
+ * some sort of compile-time limit to help catch typos.
+ */
+#ifndef MAX_THREAD_LIMIT
+#define MAX_THREAD_LIMIT 100000
+#endif
+
+/*
+ * Actual definitions of config globals
+ */
+
+int ap_threads_per_child = 0;   /* Worker threads per child */
+static int ap_daemons_to_start = 0;
+static int min_spare_threads = 0;
+static int max_spare_threads = 0;
+static int ap_daemons_limit = 0;
+static int server_limit = DEFAULT_SERVER_LIMIT;
+static int first_server_limit = 0;
+static int thread_limit = DEFAULT_THREAD_LIMIT;
+static int first_thread_limit = 0;
+static int changed_limit_at_restart;
+static int dying = 0;
+static int workers_may_exit = 0;
+static int start_thread_may_exit = 0;
+static int listener_may_exit = 0;
+static int requests_this_child;
+static int num_listensocks = 0;
+static int resource_shortage = 0;
+static fd_queue_t *worker_queue;
+static fd_queue_info_t *worker_queue_info;
+static int mpm_state = AP_MPMQ_STARTING;
+static int sick_child_detected;
+
+apr_thread_mutex_t *timeout_mutex;
+APR_RING_HEAD(timeout_head_t, conn_state_t);
+static struct timeout_head_t timeout_head;
+
+static apr_pollset_t *event_pollset;
+
+/* The structure used to pass unique initialization info to each thread */
+typedef struct
+{
+    int pid;
+    int tid;
+    int sd;
+} proc_info;
+
+/* Structure used to pass information to the thread responsible for
+ * creating the rest of the threads.
+ */
+typedef struct
+{
+    apr_thread_t **threads;
+    apr_thread_t *listener;
+    int child_num_arg;
+    apr_threadattr_t *threadattr;
+} thread_starter;
+
+typedef enum
+{
+    PT_CSD,
+    PT_ACCEPT
+} poll_type_e;
+
+typedef struct
+{
+    poll_type_e type;
+    int status;        /*XXX what is this for?  0 and 1 don't make it clear */
+    void *baton;
+} listener_poll_type;
+
+#define ID_FROM_CHILD_THREAD(c, t)    ((c * thread_limit) + t)
+
+/*
+ * The max child slot ever assigned, preserved across restarts.  Necessary
+ * to deal with MaxClients changes across AP_SIG_GRACEFUL restarts.  We
+ * use this value to optimize routines that have to scan the entire
+ * scoreboard.
+ */
+int ap_max_daemons_limit = -1;
+
+static ap_pod_t *pod;
+
+/* *Non*-shared http_main globals... */
+
+server_rec *ap_server_conf;
+
+/* The worker MPM respects a couple of runtime flags that can aid
+ * in debugging. Setting the -DNO_DETACH flag will prevent the root process
+ * from detaching from its controlling terminal. Additionally, setting
+ * the -DONE_PROCESS flag (which implies -DNO_DETACH) will get you the
+ * child_main loop running in the process which originally started up.
+ * This gives you a pretty nice debugging environment.  (You'll get a SIGHUP
+ * early in standalone_main; just continue through.  This is the server
+ * trying to kill off any child processes which it might have lying
+ * around --- Apache doesn't keep track of their pids, it just sends
+ * SIGHUP to the process group, ignoring it in the root process.
+ * Continue through and you'll be fine.).
+ */
+
+static int one_process = 0;
+
+#ifdef DEBUG_SIGSTOP
+int raise_sigstop_flags;
+#endif
+
+static apr_pool_t *pconf;       /* Pool for config stuff */
+static apr_pool_t *pchild;      /* Pool for httpd child stuff */
+
+static pid_t ap_my_pid;         /* Linux getpid() doesn't work except in main
+                                   thread. Use this instead */
+static pid_t parent_pid;
+static apr_os_thread_t *listener_os_thread;
+
+/* The LISTENER_SIGNAL signal will be sent from the main thread to the
+ * listener thread to wake it up for graceful termination (what a child
+ * process from an old generation does when the admin does "apachectl
+ * graceful").  This signal will be blocked in all threads of a child
+ * process except for the listener thread.
+ */
+#define LISTENER_SIGNAL     SIGHUP
+
+/* An array of socket descriptors in use by each thread used to
+ * perform a non-graceful (forced) shutdown of the server.
+ */
+static apr_socket_t **worker_sockets;
+
+static void close_worker_sockets(void)
+{
+    int i;
+    for (i = 0; i < ap_threads_per_child; i++) {
+        if (worker_sockets[i]) {
+            apr_socket_close(worker_sockets[i]);
+            worker_sockets[i] = NULL;
+        }
+    }
+}
+
+static void wakeup_listener(void)
+{
+    listener_may_exit = 1;
+    if (!listener_os_thread) {
+        /* XXX there is an obscure path that this doesn't handle perfectly:
+         *     right after listener thread is created but before
+         *     listener_os_thread is set, the first worker thread hits an
+         *     error and starts graceful termination
+         */
+        return;
+    }
+    /*
+     * we should just be able to "kill(ap_my_pid, LISTENER_SIGNAL)" on all
+     * platforms and wake up the listener thread since it is the only thread
+     * with SIGHUP unblocked, but that doesn't work on Linux
+     */
+#ifdef HAVE_PTHREAD_KILL
+    pthread_kill(*listener_os_thread, LISTENER_SIGNAL);
+#else
+    kill(ap_my_pid, LISTENER_SIGNAL);
+#endif
+}
+
+#define ST_INIT              0
+#define ST_GRACEFUL          1
+#define ST_UNGRACEFUL        2
+
+static int terminate_mode = ST_INIT;
+
+static void signal_threads(int mode)
+{
+    if (terminate_mode == mode) {
+        return;
+    }
+    terminate_mode = mode;
+    mpm_state = AP_MPMQ_STOPPING;
+
+    /* in case we weren't called from the listener thread, wake up the
+     * listener thread
+     */
+    wakeup_listener();
+
+    /* for ungraceful termination, let the workers exit now;
+     * for graceful termination, the listener thread will notify the
+     * workers to exit once it has stopped accepting new connections
+     */
+    if (mode == ST_UNGRACEFUL) {
+        workers_may_exit = 1;
+        ap_queue_interrupt_all(worker_queue);
+        ap_queue_info_term(worker_queue_info);
+        close_worker_sockets(); /* forcefully kill all current connections */
+    }
+}
+
+AP_DECLARE(apr_status_t) ap_mpm_query(int query_code, int *result)
+{
+    switch (query_code) {
+    case AP_MPMQ_MAX_DAEMON_USED:
+        *result = ap_max_daemons_limit;
+        return APR_SUCCESS;
+    case AP_MPMQ_IS_THREADED:
+        *result = AP_MPMQ_STATIC;
+        return APR_SUCCESS;
+    case AP_MPMQ_IS_FORKED:
+        *result = AP_MPMQ_DYNAMIC;
+        return APR_SUCCESS;
+    case AP_MPMQ_IS_ASYNC:
+        *result = 1;
+        return APR_SUCCESS;
+    case AP_MPMQ_HARD_LIMIT_DAEMONS:
+        *result = server_limit;
+        return APR_SUCCESS;
+    case AP_MPMQ_HARD_LIMIT_THREADS:
+        *result = thread_limit;
+        return APR_SUCCESS;
+    case AP_MPMQ_MAX_THREADS:
+        *result = ap_threads_per_child;
+        return APR_SUCCESS;
+    case AP_MPMQ_MIN_SPARE_DAEMONS:
+        *result = 0;
+        return APR_SUCCESS;
+    case AP_MPMQ_MIN_SPARE_THREADS:
+        *result = min_spare_threads;
+        return APR_SUCCESS;
+    case AP_MPMQ_MAX_SPARE_DAEMONS:
+        *result = 0;
+        return APR_SUCCESS;
+    case AP_MPMQ_MAX_SPARE_THREADS:
+        *result = max_spare_threads;
+        return APR_SUCCESS;
+    case AP_MPMQ_MAX_REQUESTS_DAEMON:
+        *result = ap_max_requests_per_child;
+        return APR_SUCCESS;
+    case AP_MPMQ_MAX_DAEMONS:
+        *result = ap_daemons_limit;
+        return APR_SUCCESS;
+    case AP_MPMQ_MPM_STATE:
+        *result = mpm_state;
+        return APR_SUCCESS;
+    }
+    return APR_ENOTIMPL;
+}
+
+/* a clean exit from a child with proper cleanup */
+static void clean_child_exit(int code) __attribute__ ((noreturn));
+static void clean_child_exit(int code)
+{
+    mpm_state = AP_MPMQ_STOPPING;
+    if (pchild) {
+        apr_pool_destroy(pchild);
+    }
+    exit(code);
+}
+
+static void just_die(int sig)
+{
+    clean_child_exit(0);
+}
+
+/*****************************************************************
+ * Connection structures and accounting...
+ */
+
+/* volatile just in case */
+static int volatile shutdown_pending;
+static int volatile restart_pending;
+static int volatile is_graceful;
+static volatile int child_fatal;
+ap_generation_t volatile ap_my_generation;
+
+/*
+ * ap_start_shutdown() and ap_start_restart(), below, are a first stab at
+ * functions to initiate shutdown or restart without relying on signals.
+ * Previously this was initiated in sig_term() and restart() signal handlers,
+ * but we want to be able to start a shutdown/restart from other sources --
+ * e.g. on Win32, from the service manager. Now the service manager can
+ * call ap_start_shutdown() or ap_start_restart() as appropiate.  Note that
+ * these functions can also be called by the child processes, since global
+ * variables are no longer used to pass on the required action to the parent.
+ *
+ * These should only be called from the parent process itself, since the
+ * parent process will use the shutdown_pending and restart_pending variables
+ * to determine whether to shutdown or restart. The child process should
+ * call signal_parent() directly to tell the parent to die -- this will
+ * cause neither of those variable to be set, which the parent will
+ * assume means something serious is wrong (which it will be, for the
+ * child to force an exit) and so do an exit anyway.
+ */
+
+static void ap_start_shutdown(int graceful)
+{
+    mpm_state = AP_MPMQ_STOPPING;
+    if (shutdown_pending == 1) {
+        /* Um, is this _probably_ not an error, if the user has
+         * tried to do a shutdown twice quickly, so we won't
+         * worry about reporting it.
+         */
+        return;
+    }
+    shutdown_pending = 1;
+    is_graceful = graceful;
+}
+
+/* do a graceful restart if graceful == 1 */
+static void ap_start_restart(int graceful)
+{
+    mpm_state = AP_MPMQ_STOPPING;
+    if (restart_pending == 1) {
+        /* Probably not an error - don't bother reporting it */
+        return;
+    }
+    restart_pending = 1;
+    is_graceful = graceful;
+}
+
+static void sig_term(int sig)
+{
+    ap_start_shutdown(sig == AP_SIG_GRACEFUL_STOP);
+}
+
+static void restart(int sig)
+{
+    ap_start_restart(sig == AP_SIG_GRACEFUL);
+}
+
+static void set_signals(void)
+{
+#ifndef NO_USE_SIGACTION
+    struct sigaction sa;
+#endif
+
+    if (!one_process) {
+        ap_fatal_signal_setup(ap_server_conf, pconf);
+    }
+
+#ifndef NO_USE_SIGACTION
+    sigemptyset(&sa.sa_mask);
+    sa.sa_flags = 0;
+
+    sa.sa_handler = sig_term;
+    if (sigaction(SIGTERM, &sa, NULL) < 0)
+        ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf,
+                     "sigaction(SIGTERM)");
+#ifdef AP_SIG_GRACEFUL_STOP
+    if (sigaction(AP_SIG_GRACEFUL_STOP, &sa, NULL) < 0)
+        ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf,
+                     "sigaction(" AP_SIG_GRACEFUL_STOP_STRING ")");
+#endif
+#ifdef SIGINT
+    if (sigaction(SIGINT, &sa, NULL) < 0)
+        ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf,
+                     "sigaction(SIGINT)");
+#endif
+#ifdef SIGXCPU
+    sa.sa_handler = SIG_DFL;
+    if (sigaction(SIGXCPU, &sa, NULL) < 0)
+        ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf,
+                     "sigaction(SIGXCPU)");
+#endif
+#ifdef SIGXFSZ
+    sa.sa_handler = SIG_DFL;
+    if (sigaction(SIGXFSZ, &sa, NULL) < 0)
+        ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf,
+                     "sigaction(SIGXFSZ)");
+#endif
+#ifdef SIGPIPE
+    sa.sa_handler = SIG_IGN;
+    if (sigaction(SIGPIPE, &sa, NULL) < 0)
+        ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf,
+                     "sigaction(SIGPIPE)");
+#endif
+
+    /* we want to ignore HUPs and AP_SIG_GRACEFUL while we're busy
+     * processing one */
+    sigaddset(&sa.sa_mask, SIGHUP);
+    sigaddset(&sa.sa_mask, AP_SIG_GRACEFUL);
+    sa.sa_handler = restart;
+    if (sigaction(SIGHUP, &sa, NULL) < 0)
+        ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf,
+                     "sigaction(SIGHUP)");
+    if (sigaction(AP_SIG_GRACEFUL, &sa, NULL) < 0)
+        ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf,
+                     "sigaction(" AP_SIG_GRACEFUL_STRING ")");
+#else
+    if (!one_process) {
+#ifdef SIGXCPU
+        apr_signal(SIGXCPU, SIG_DFL);
+#endif /* SIGXCPU */
+#ifdef SIGXFSZ
+        apr_signal(SIGXFSZ, SIG_DFL);
+#endif /* SIGXFSZ */
+    }
+
+    apr_signal(SIGTERM, sig_term);
+#ifdef SIGHUP
+    apr_signal(SIGHUP, restart);
+#endif /* SIGHUP */
+#ifdef AP_SIG_GRACEFUL
+    apr_signal(AP_SIG_GRACEFUL, restart);
+#endif /* AP_SIG_GRACEFUL */
+#ifdef AP_SIG_GRACEFUL_STOP
+     apr_signal(AP_SIG_GRACEFUL_STOP, sig_term);
+#endif /* AP_SIG_GRACEFUL_STOP */
+#ifdef SIGPIPE
+    apr_signal(SIGPIPE, SIG_IGN);
+#endif /* SIGPIPE */
+
+#endif
+}
+
+/*****************************************************************
+ * Here follows a long bunch of generic server bookkeeping stuff...
+ */
+
+int ap_graceful_stop_signalled(void)
+    /* XXX this is really a bad confusing obsolete name
+     * maybe it should be ap_mpm_process_exiting?
+     */
+{
+    /* note: for a graceful termination, listener_may_exit will be set before
+     *       workers_may_exit, so check listener_may_exit
+     */
+    return listener_may_exit;
+}
+
+/*****************************************************************
+ * Child process main loop.
+ */
+
+static int process_socket(apr_pool_t * p, apr_socket_t * sock,
+                          conn_state_t * cs, int my_child_num,
+                          int my_thread_num)
+{
+    conn_rec *c;
+    listener_poll_type *pt;
+    long conn_id = ID_FROM_CHILD_THREAD(my_child_num, my_thread_num);
+    int csd;
+    int rc;
+    apr_time_t time_now = 0;
+    ap_sb_handle_t *sbh;
+
+    ap_create_sb_handle(&sbh, p, my_child_num, my_thread_num);
+    apr_os_sock_get(&csd, sock);
+
+    time_now = apr_time_now();
+
+    if (cs == NULL) {           /* This is a new connection */
+
+        cs = apr_pcalloc(p, sizeof(conn_state_t));
+
+        pt = apr_pcalloc(p, sizeof(*pt));
+
+        cs->bucket_alloc = apr_bucket_alloc_create(p);
+        c = ap_run_create_connection(p, ap_server_conf, sock,
+                                     conn_id, sbh, cs->bucket_alloc);
+        cs->c = c;
+        c->cs = cs;
+        cs->p = p;
+        cs->pfd.desc_type = APR_POLL_SOCKET;
+        cs->pfd.reqevents = APR_POLLIN;
+        cs->pfd.desc.s = sock;
+        pt->type = PT_CSD;
+        pt->status = 1;
+        pt->baton = cs;
+        cs->pfd.client_data = pt;
+
+        ap_update_vhost_given_ip(c);
+
+        rc = ap_run_pre_connection(c, sock);
+        if (rc != OK && rc != DONE) {
+            ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf,
+                         "process_socket: connection aborted");
+            c->aborted = 1;
+        }
+
+        /**
+         * XXX If the platform does not have a usable way of bundling
+         * accept() with a socket readability check, like Win32,
+         * and there are measurable delays before the
+         * socket is readable due to the first data packet arriving,
+         * it might be better to create the cs on the listener thread
+         * with the state set to CONN_STATE_CHECK_REQUEST_LINE_READABLE
+         *
+         * FreeBSD users will want to enable the HTTP accept filter
+         * module in their kernel for the highest performance
+         * When the accept filter is active, sockets are kept in the
+         * kernel until a HTTP request is received.
+         */
+        cs->state = CONN_STATE_READ_REQUEST_LINE;
+
+    }
+    else {
+        c = cs->c;
+        c->sbh = sbh;
+    }
+
+    if (cs->state == CONN_STATE_READ_REQUEST_LINE) {
+        if (!c->aborted) {
+            ap_run_process_connection(c);
+
+            /* state will be updated upon return
+             * fall thru to either wait for readability/timeout or
+             * do lingering close
+             */
+        }
+        else {
+            cs->state = CONN_STATE_LINGER;
+        }
+    }
+
+    if (cs->state == CONN_STATE_LINGER) {
+        ap_lingering_close(c);
+        apr_bucket_alloc_destroy(cs->bucket_alloc);
+        apr_pool_clear(p);
+        ap_push_pool(worker_queue_info, p);
+        return 1;
+    }
+    else if (cs->state == CONN_STATE_CHECK_REQUEST_LINE_READABLE) {
+        apr_status_t rc;
+        listener_poll_type *pt = (listener_poll_type *) cs->pfd.client_data;
+
+        /* It greatly simplifies the logic to use a single timeout value here
+         * because the new element can just be added to the end of the list and
+         * it will stay sorted in expiration time sequence.  If brand new
+         * sockets are sent to the event thread for a readability check, this
+         * will be a slight behavior change - they use the non-keepalive
+         * timeout today.  With a normal client, the socket will be readable in
+         * a few milliseconds anyway.
+         */
+        cs->expiration_time = ap_server_conf->keep_alive_timeout + time_now;
+        apr_thread_mutex_lock(timeout_mutex);
+        APR_RING_INSERT_TAIL(&timeout_head, cs, conn_state_t, timeout_list);
+
+        pt->status = 0;
+        /* Add work to pollset. These are always read events */
+        rc = apr_pollset_add(event_pollset, &cs->pfd);
+
+        apr_thread_mutex_unlock(timeout_mutex);
+
+        if (rc != APR_SUCCESS) {
+            ap_log_error(APLOG_MARK, APLOG_ERR, rc, ap_server_conf,
+                         "process_socket: apr_pollset_add failure");
+            AP_DEBUG_ASSERT(rc == APR_SUCCESS);
+        }
+    }
+    return 0;
+}
+
+/* requests_this_child has gone to zero or below.  See if the admin coded
+   "MaxRequestsPerChild 0", and keep going in that case.  Doing it this way
+   simplifies the hot path in worker_thread */
+static void check_infinite_requests(void)
+{
+    if (ap_max_requests_per_child) {
+        signal_threads(ST_GRACEFUL);
+    }
+    else {
+        /* wow! if you're executing this code, you may have set a record.
+         * either this child process has served over 2 billion requests, or
+         * you're running a threaded 2.0 on a 16 bit machine.
+         *
+         * I'll buy pizza and beers at Apachecon for the first person to do
+         * the former without cheating (dorking with INT_MAX, or running with
+         * uncommitted performance patches, for example).
+         *
+         * for the latter case, you probably deserve a beer too.   Greg Ames
+         */
+
+        requests_this_child = INT_MAX;  /* keep going */
+    }
+}
+
+static void unblock_signal(int sig)
+{
+    sigset_t sig_mask;
+
+    sigemptyset(&sig_mask);
+    sigaddset(&sig_mask, sig);
+#if defined(SIGPROCMASK_SETS_THREAD_MASK)
+    sigprocmask(SIG_UNBLOCK, &sig_mask, NULL);
+#else
+    pthread_sigmask(SIG_UNBLOCK, &sig_mask, NULL);
+#endif
+}
+
+static void dummy_signal_handler(int sig)
+{
+    /* XXX If specifying SIG_IGN is guaranteed to unblock a syscall,
+     *     then we don't need this goofy function.
+     */
+}
+
+static apr_status_t push2worker(const apr_pollfd_t * pfd,
+                                apr_pollset_t * pollset)
+{
+    listener_poll_type *pt = (listener_poll_type *) pfd->client_data;
+    conn_state_t *cs = (conn_state_t *) pt->baton;
+    apr_status_t rc;
+
+    if (pt->status == 1) {
+        return 0;
+    }
+
+    pt->status = 1;
+
+    rc = apr_pollset_remove(pollset, pfd);
+
+    /*
+     * Some of the pollset backends, like KQueue or Epoll
+     * automagically remove the FD if the socket is closed,
+     * therefore, we can accept _SUCCESS or _NOTFOUND,
+     * and we still want to keep going
+     */
+    if (rc != APR_SUCCESS && rc != APR_NOTFOUND) {
+        cs->state = CONN_STATE_LINGER;
+    }
+
+    rc = ap_queue_push(worker_queue, cs->pfd.desc.s, cs, cs->p);
+    if (rc != APR_SUCCESS) {
+        /* trash the connection; we couldn't queue the connected
+         * socket to a worker
+         */
+        apr_bucket_alloc_destroy(cs->bucket_alloc);
+        apr_socket_close(cs->pfd.desc.s);
+        ap_log_error(APLOG_MARK, APLOG_CRIT, rc,
+                     ap_server_conf, "push2worker: ap_queue_push failed");
+        apr_pool_clear(cs->p);
+        ap_push_pool(worker_queue_info, cs->p);
+    }
+
+    return APR_SUCCESS;
+}
+
+/* get_worker:
+ *     reserve a worker thread, block if all are currently busy.
+ *     this prevents the worker queue from overflowing and lets
+ *     other processes accept new connections in the mean time.
+ */
+static int get_worker(int *have_idle_worker_p)
+{
+    apr_status_t rc;
+
+    if (!*have_idle_worker_p) {
+        rc = ap_queue_info_wait_for_idler(worker_queue_info);
+
+        if (rc == APR_SUCCESS) {
+            *have_idle_worker_p = 1;
+            return 1;
+        }
+        else {
+            if (!APR_STATUS_IS_EOF(rc)) {
+                ap_log_error(APLOG_MARK, APLOG_ERR, rc, ap_server_conf,
+                             "ap_queue_info_wait_for_idler failed.  "
+                             "Attempting to shutdown process gracefully");
+                signal_threads(ST_GRACEFUL);
+            }
+            return 0;
+        }
+    }
+    else {
+        /* already reserved a worker thread - must have hit a
+         * transient error on a previous pass
+         */
+        return 1;
+    }
+}
+
+static void *listener_thread(apr_thread_t * thd, void *dummy)
+{
+    apr_status_t rc;
+    proc_info *ti = dummy;
+    int process_slot = ti->pid;
+    apr_pool_t *tpool = apr_thread_pool_get(thd);
+    void *csd = NULL;
+    apr_pool_t *ptrans;         /* Pool for per-transaction stuff */
+    ap_listen_rec *lr;
+    int have_idle_worker = 0;
+    conn_state_t *cs;
+    const apr_pollfd_t *out_pfd;
+    apr_int32_t num = 0;
+    apr_time_t time_now = 0;
+    apr_interval_time_t timeout_interval;
+    apr_time_t timeout_time;
+    listener_poll_type *pt;
+
+    free(ti);
+
+    /* We set this to force apr_pollset to wakeup if there hasn't been any IO
+     * on any of its sockets.  This allows sockets to have been added
+     * when no other keepalive operations where going on.
+     *
+     * current value is 1 second
+     */
+    timeout_interval = 1000000;
+
+    /* the following times out events that are really close in the future
+     *   to prevent extra poll calls
+     *
+     * current value is .1 second
+     */
+#define TIMEOUT_FUDGE_FACTOR 100000
+
+    /* POLLSET_SCALE_FACTOR * ap_threads_per_child sets the size of
+     * the pollset.  I've seen 15 connections per active worker thread
+     * running SPECweb99.
+     *
+     * However, with the newer apr_pollset, this is the number of sockets that
+     * we will return to any *one* call to poll().  Therefore, there is no
+     * reason to make it more than ap_threads_per_child.
+     */
+#define POLLSET_SCALE_FACTOR 1
+
+    rc = apr_thread_mutex_create(&timeout_mutex, APR_THREAD_MUTEX_DEFAULT,
+                                 tpool);
+    if (rc != APR_SUCCESS) {
+        ap_log_error(APLOG_MARK, APLOG_ERR, rc, ap_server_conf,
+                     "creation of the timeout mutex failed.  Attempting to "
+                     "shutdown process gracefully");
+        signal_threads(ST_GRACEFUL);
+        return NULL;
+    }
+
+    APR_RING_INIT(&timeout_head, conn_state_t, timeout_list);
+
+    /* Create the main pollset */
+    rc = apr_pollset_create(&event_pollset,
+                            ap_threads_per_child * POLLSET_SCALE_FACTOR,
+                            tpool, APR_POLLSET_THREADSAFE);
+    if (rc != APR_SUCCESS) {
+        ap_log_error(APLOG_MARK, APLOG_ERR, rc, ap_server_conf,
+                     "apr_pollset_create with Thread Safety failed. "
+                     "Attempting to shutdown process gracefully");
+        signal_threads(ST_GRACEFUL);
+        return NULL;
+    }
+
+    for (lr = ap_listeners; lr != NULL; lr = lr->next) {
+        apr_pollfd_t pfd = { 0 };
+        pt = apr_pcalloc(tpool, sizeof(*pt));
+        pfd.desc_type = APR_POLL_SOCKET;
+        pfd.desc.s = lr->sd;
+        pfd.reqevents = APR_POLLIN;
+
+        pt->type = PT_ACCEPT;
+        pt->baton = lr;
+
+        pfd.client_data = pt;
+
+        apr_socket_opt_set(pfd.desc.s, APR_SO_NONBLOCK, 1);
+        apr_pollset_add(event_pollset, &pfd);
+    }
+
+    /* Unblock the signal used to wake this thread up, and set a handler for
+     * it.
+     */
+    unblock_signal(LISTENER_SIGNAL);
+    apr_signal(LISTENER_SIGNAL, dummy_signal_handler);
+
+    while (!listener_may_exit) {
+
+        if (requests_this_child <= 0) {
+            check_infinite_requests();
+        }
+
+        rc = apr_pollset_poll(event_pollset, timeout_interval, &num,
+                              &out_pfd);
+
+        if (rc != APR_SUCCESS) {
+            if (APR_STATUS_IS_EINTR(rc)) {
+                continue;
+            }
+            if (!APR_STATUS_IS_TIMEUP(rc)) {
+                ap_log_error(APLOG_MARK, APLOG_ERR, rc, ap_server_conf,
+                             "apr_pollset_poll failed.  Attempting to "
+                             "shutdown process gracefully");
+                signal_threads(ST_GRACEFUL);
+            }
+        }
+
+        if (listener_may_exit)
+            break;
+
+        while (num && get_worker(&have_idle_worker)) {
+            pt = (listener_poll_type *) out_pfd->client_data;
+            if (pt->type == PT_CSD) {
+                /* one of the sockets is readable */
+                cs = (conn_state_t *) pt->baton;
+                switch (cs->state) {
+                case CONN_STATE_CHECK_REQUEST_LINE_READABLE:
+                    cs->state = CONN_STATE_READ_REQUEST_LINE;
+                    break;
+                default:
+                    ap_log_error(APLOG_MARK, APLOG_ERR, rc,
+                                 ap_server_conf,
+                                 "event_loop: unexpected state %d",
+                                 cs->state);
+                    AP_DEBUG_ASSERT(0);
+                }
+
+                apr_thread_mutex_lock(timeout_mutex);
+                APR_RING_REMOVE(cs, timeout_list);
+                apr_thread_mutex_unlock(timeout_mutex);
+
+                rc = push2worker(out_pfd, event_pollset);
+                if (rc != APR_SUCCESS) {
+                    ap_log_error(APLOG_MARK, APLOG_CRIT, rc,
+                                 ap_server_conf, "push2worker failed");
+                }
+                else {
+                    have_idle_worker = 0;
+                }
+            }
+            else {
+                /* A Listener Socket is ready for an accept() */
+                apr_pool_t *recycled_pool = NULL;
+
+                lr = (ap_listen_rec *) pt->baton;
+
+                ap_pop_pool(&recycled_pool, worker_queue_info);
+
+                if (recycled_pool == NULL) {
+                    /* create a new transaction pool for each accepted socket */
+                    apr_allocator_t *allocator;
+
+                    apr_allocator_create(&allocator);
+                    apr_allocator_max_free_set(allocator,
+                                               ap_max_mem_free);
+                    apr_pool_create_ex(&ptrans, pconf, NULL, allocator);
+                    apr_allocator_owner_set(allocator, ptrans);
+                    if (ptrans == NULL) {
+                        ap_log_error(APLOG_MARK, APLOG_CRIT, rc,
+                                     ap_server_conf,
+                                     "Failed to create transaction pool");
+                        signal_threads(ST_GRACEFUL);
+                        return NULL;
+                    }
+                }
+                else {
+                    ptrans = recycled_pool;
+                }
+
+                apr_pool_tag(ptrans, "transaction");
+
+                rc = lr->accept_func(&csd, lr, ptrans);
+
+                /* later we trash rv and rely on csd to indicate
+                 * success/failure
+                 */
+                AP_DEBUG_ASSERT(rc == APR_SUCCESS || !csd);
+
+                if (rc == APR_EGENERAL) {
+                    /* E[NM]FILE, ENOMEM, etc */
+                    resource_shortage = 1;
+                    signal_threads(ST_GRACEFUL);
+                }
+
+                if (csd != NULL) {
+                    rc = ap_queue_push(worker_queue, csd, NULL, ptrans);
+                    if (rc != APR_SUCCESS) {
+                        /* trash the connection; we couldn't queue the connected
+                         * socket to a worker
+                         */
+                        apr_socket_close(csd);
+                        ap_log_error(APLOG_MARK, APLOG_CRIT, rc,
+                                     ap_server_conf,
+                                     "ap_queue_push failed");
+                        apr_pool_clear(ptrans);
+                        ap_push_pool(worker_queue_info, ptrans);
+                    }
+                    else {
+                        have_idle_worker = 0;
+                    }
+                }
+                else {
+                    apr_pool_clear(ptrans);
+                    ap_push_pool(worker_queue_info, ptrans);
+                }
+            }               /* if:else on pt->type */
+            out_pfd++;
+            num--;
+        }                   /* while for processing poll */
+
+        /* XXX possible optimization: stash the current time for use as
+         * r->request_time for new requests
+         */
+        time_now = apr_time_now();
+
+        /* handle timed out sockets */
+        apr_thread_mutex_lock(timeout_mutex);
+
+        cs = APR_RING_FIRST(&timeout_head);
+        timeout_time = time_now + TIMEOUT_FUDGE_FACTOR;
+        while (!APR_RING_EMPTY(&timeout_head, conn_state_t, timeout_list)
+               && cs->expiration_time < timeout_time
+               && get_worker(&have_idle_worker)) {
+
+            cs->state = CONN_STATE_LINGER;
+
+            APR_RING_REMOVE(cs, timeout_list);
+
+            rc = push2worker(&cs->pfd, event_pollset);
+
+            if (rc != APR_SUCCESS) {
+                return NULL;
+                /* XXX return NULL looks wrong - not an init failure
+                 * that bypasses all the cleanup outside the main loop
+                 * break seems more like it
+                 * need to evaluate seriousness of push2worker failures
+                 */
+            }
+            have_idle_worker = 0;
+            cs = APR_RING_FIRST(&timeout_head);
+        }
+        apr_thread_mutex_unlock(timeout_mutex);
+
+    }     /* listener main loop */
+
+    ap_close_listeners();
+    ap_queue_term(worker_queue);
+    dying = 1;
+    ap_scoreboard_image->parent[process_slot].quiescing = 1;
+
+    /* wake up the main thread */
+    kill(ap_my_pid, SIGTERM);
+
+    apr_thread_exit(thd, APR_SUCCESS);
+    return NULL;
+}
+
+/* XXX For ungraceful termination/restart, we definitely don't want to
+ *     wait for active connections to finish but we may want to wait
+ *     for idle workers to get out of the queue code and release mutexes,
+ *     since those mutexes are cleaned up pretty soon and some systems
+ *     may not react favorably (i.e., segfault) if operations are attempted
+ *     on cleaned-up mutexes.
+ */
+static void *APR_THREAD_FUNC worker_thread(apr_thread_t * thd, void *dummy)
+{
+    proc_info *ti = dummy;
+    int process_slot = ti->pid;
+    int thread_slot = ti->tid;
+    apr_socket_t *csd = NULL;
+    conn_state_t *cs;
+    apr_pool_t *ptrans;         /* Pool for per-transaction stuff */
+    apr_status_t rv;
+    int is_idle = 0;
+
+    free(ti);
+
+    ap_scoreboard_image->servers[process_slot][thread_slot].pid = ap_my_pid;
+    ap_scoreboard_image->servers[process_slot][thread_slot].generation = ap_my_generation;
+    ap_update_child_status_from_indexes(process_slot, thread_slot,
+                                        SERVER_STARTING, NULL);
+
+    while (!workers_may_exit) {
+        if (!is_idle) {
+            rv = ap_queue_info_set_idle(worker_queue_info, NULL);
+            if (rv != APR_SUCCESS) {
+                ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf,
+                             "ap_queue_info_set_idle failed. Attempting to "
+                             "shutdown process gracefully.");
+                signal_threads(ST_GRACEFUL);
+                break;
+            }
+            is_idle = 1;
+        }
+
+        ap_update_child_status_from_indexes(process_slot, thread_slot,
+                                            SERVER_READY, NULL);
+      worker_pop:
+        if (workers_may_exit) {
+            break;
+        }
+        rv = ap_queue_pop(worker_queue, &csd, &cs, &ptrans);
+
+        if (rv != APR_SUCCESS) {
+            /* We get APR_EOF during a graceful shutdown once all the
+             * connections accepted by this server process have been handled.
+             */
+            if (APR_STATUS_IS_EOF(rv)) {
+                break;
+            }
+            /* We get APR_EINTR whenever ap_queue_pop() has been interrupted
+             * from an explicit call to ap_queue_interrupt_all(). This allows
+             * us to unblock threads stuck in ap_queue_pop() when a shutdown
+             * is pending.
+             *
+             * If workers_may_exit is set and this is ungraceful termination/
+             * restart, we are bound to get an error on some systems (e.g.,
+             * AIX, which sanity-checks mutex operations) since the queue
+             * may have already been cleaned up.  Don't log the "error" if
+             * workers_may_exit is set.
+             */
+            else if (APR_STATUS_IS_EINTR(rv)) {
+                goto worker_pop;
+            }
+            /* We got some other error. */
+            else if (!workers_may_exit) {
+                ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ap_server_conf,
+                             "ap_queue_pop failed");
+            }
+            continue;
+        }
+        is_idle = 0;
+        worker_sockets[thread_slot] = csd;
+        rv = process_socket(ptrans, csd, cs, process_slot, thread_slot);
+        if (!rv) {
+            requests_this_child--;
+        }
+        worker_sockets[thread_slot] = NULL;
+    }
+
+    ap_update_child_status_from_indexes(process_slot, thread_slot,
+                                        (dying) ? SERVER_DEAD :
+                                        SERVER_GRACEFUL,
+                                        (request_rec *) NULL);
+
+    apr_thread_exit(thd, APR_SUCCESS);
+    return NULL;
+}
+
+static int check_signal(int signum)
+{
+    switch (signum) {
+    case SIGTERM:
+    case SIGINT:
+        return 1;
+    }
+    return 0;
+}
+
+
+
+static void create_listener_thread(thread_starter * ts)
+{
+    int my_child_num = ts->child_num_arg;
+    apr_threadattr_t *thread_attr = ts->threadattr;
+    proc_info *my_info;
+    apr_status_t rv;
+
+    my_info = (proc_info *) malloc(sizeof(proc_info));
+    my_info->pid = my_child_num;
+    my_info->tid = -1;          /* listener thread doesn't have a thread slot */
+    my_info->sd = 0;
+    rv = apr_thread_create(&ts->listener, thread_attr, listener_thread,
+                           my_info, pchild);
+    if (rv != APR_SUCCESS) {
+        ap_log_error(APLOG_MARK, APLOG_ALERT, rv, ap_server_conf,
+                     "apr_thread_create: unable to create listener thread");
+        /* let the parent decide how bad this really is */
+        clean_child_exit(APEXIT_CHILDSICK);
+    }
+    apr_os_thread_get(&listener_os_thread, ts->listener);
+}
+
+/* XXX under some circumstances not understood, children can get stuck
+ *     in start_threads forever trying to take over slots which will
+ *     never be cleaned up; for now there is an APLOG_DEBUG message issued
+ *     every so often when this condition occurs
+ */
+static void *APR_THREAD_FUNC start_threads(apr_thread_t * thd, void *dummy)
+{
+    thread_starter *ts = dummy;
+    apr_thread_t **threads = ts->threads;
+    apr_threadattr_t *thread_attr = ts->threadattr;
+    int child_num_arg = ts->child_num_arg;
+    int my_child_num = child_num_arg;
+    proc_info *my_info;
+    apr_status_t rv;
+    int i;
+    int threads_created = 0;
+    int listener_started = 0;
+    int loops;
+    int prev_threads_created;
+
+    /* We must create the fd queues before we start up the listener
+     * and worker threads. */
+    worker_queue = apr_pcalloc(pchild, sizeof(*worker_queue));
+    rv = ap_queue_init(worker_queue, ap_threads_per_child, pchild);
+    if (rv != APR_SUCCESS) {
+        ap_log_error(APLOG_MARK, APLOG_ALERT, rv, ap_server_conf,
+                     "ap_queue_init() failed");
+        clean_child_exit(APEXIT_CHILDFATAL);
+    }
+
+    rv = ap_queue_info_create(&worker_queue_info, pchild,
+                              ap_threads_per_child);
+    if (rv != APR_SUCCESS) {
+        ap_log_error(APLOG_MARK, APLOG_ALERT, rv, ap_server_conf,
+                     "ap_queue_info_create() failed");
+        clean_child_exit(APEXIT_CHILDFATAL);
+    }
+
+    worker_sockets = apr_pcalloc(pchild, ap_threads_per_child
+                                 * sizeof(apr_socket_t *));
+
+    loops = prev_threads_created = 0;
+    while (1) {
+        /* ap_threads_per_child does not include the listener thread */
+        for (i = 0; i < ap_threads_per_child; i++) {
+            int status =
+                ap_scoreboard_image->servers[child_num_arg][i].status;
+
+            if (status != SERVER_GRACEFUL && status != SERVER_DEAD) {
+                continue;
+            }
+
+            my_info = (proc_info *) malloc(sizeof(proc_info));
+            if (my_info == NULL) {
+                ap_log_error(APLOG_MARK, APLOG_ALERT, errno, ap_server_conf,
+                             "malloc: out of memory");
+                clean_child_exit(APEXIT_CHILDFATAL);
+            }
+            my_info->pid = my_child_num;
+            my_info->tid = i;
+            my_info->sd = 0;
+
+            /* We are creating threads right now */
+            ap_update_child_status_from_indexes(my_child_num, i,
+                                                SERVER_STARTING, NULL);
+            /* We let each thread update its own scoreboard entry.  This is
+             * done because it lets us deal with tid better.
+             */
+            rv = apr_thread_create(&threads[i], thread_attr,
+                                   worker_thread, my_info, pchild);
+            if (rv != APR_SUCCESS) {
+                ap_log_error(APLOG_MARK, APLOG_ALERT, rv, ap_server_conf,
+                             "apr_thread_create: unable to create worker thread");
+                /* let the parent decide how bad this really is */
+                clean_child_exit(APEXIT_CHILDSICK);
+            }
+            threads_created++;
+        }
+
+        /* Start the listener only when there are workers available */
+        if (!listener_started && threads_created) {
+            create_listener_thread(ts);
+            listener_started = 1;
+        }
+
+
+        if (start_thread_may_exit || threads_created == ap_threads_per_child) {
+            break;
+        }
+        /* wait for previous generation to clean up an entry */
+        apr_sleep(apr_time_from_sec(1));
+        ++loops;
+        if (loops % 120 == 0) { /* every couple of minutes */
+            if (prev_threads_created == threads_created) {
+                ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf,
+                             "child %" APR_PID_T_FMT " isn't taking over "
+                             "slots very quickly (%d of %d)",
+                             ap_my_pid, threads_created,
+                             ap_threads_per_child);
+            }
+            prev_threads_created = threads_created;
+        }
+    }
+
+    /* What state should this child_main process be listed as in the
+     * scoreboard...?
+     *  ap_update_child_status_from_indexes(my_child_num, i, SERVER_STARTING,
+     *                                      (request_rec *) NULL);
+     *
+     *  This state should be listed separately in the scoreboard, in some kind
+     *  of process_status, not mixed in with the worker threads' status.
+     *  "life_status" is almost right, but it's in the worker's structure, and
+     *  the name could be clearer.   gla
+     */
+    apr_thread_exit(thd, APR_SUCCESS);
+    return NULL;
+}
+
+static void join_workers(apr_thread_t * listener, apr_thread_t ** threads)
+{
+    int i;
+    apr_status_t rv, thread_rv;
+
+    if (listener) {
+        int iter;
+
+        /* deal with a rare timing window which affects waking up the
+         * listener thread...  if the signal sent to the listener thread
+         * is delivered between the time it verifies that the
+         * listener_may_exit flag is clear and the time it enters a
+         * blocking syscall, the signal didn't do any good...  work around
+         * that by sleeping briefly and sending it again
+         */
+
+        iter = 0;
+        while (iter < 10 &&
+#ifdef HAVE_PTHREAD_KILL
+               pthread_kill(*listener_os_thread, 0)
+#else
+               kill(ap_my_pid, 0)
+#endif
+               == 0) {
+            /* listener not dead yet */
+            apr_sleep(apr_time_make(0, 500000));
+            wakeup_listener();
+            ++iter;
+        }
+        if (iter >= 10) {
+            ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf,
+                         "the listener thread didn't exit");
+        }
+        else {
+            rv = apr_thread_join(&thread_rv, listener);
+            if (rv != APR_SUCCESS) {
+                ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ap_server_conf,
+                             "apr_thread_join: unable to join listener thread");
+            }
+        }
+    }
+
+    for (i = 0; i < ap_threads_per_child; i++) {
+        if (threads[i]) {       /* if we ever created this thread */
+            rv = apr_thread_join(&thread_rv, threads[i]);
+            if (rv != APR_SUCCESS) {
+                ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ap_server_conf,
+                             "apr_thread_join: unable to join worker "
+                             "thread %d", i);
+            }
+        }
+    }
+}
+
+static void join_start_thread(apr_thread_t * start_thread_id)
+{
+    apr_status_t rv, thread_rv;
+
+    start_thread_may_exit = 1;  /* tell it to give up in case it is still
+                                 * trying to take over slots from a
+                                 * previous generation
+                                 */
+    rv = apr_thread_join(&thread_rv, start_thread_id);
+    if (rv != APR_SUCCESS) {
+        ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ap_server_conf,
+                     "apr_thread_join: unable to join the start " "thread");
+    }
+}
+
+static void child_main(int child_num_arg)
+{
+    apr_thread_t **threads;
+    apr_status_t rv;
+    thread_starter *ts;
+    apr_threadattr_t *thread_attr;
+    apr_thread_t *start_thread_id;
+
+    mpm_state = AP_MPMQ_STARTING;       /* for benefit of any hooks that run as this
+                                         * child initializes
+                                         */
+    ap_my_pid = getpid();
+    ap_fatal_signal_child_setup(ap_server_conf);
+    apr_pool_create(&pchild, pconf);
+
+    /*stuff to do before we switch id's, so we have permissions. */
+    ap_reopen_scoreboard(pchild, NULL, 0);
+
+    if (unixd_setup_child()) {
+        clean_child_exit(APEXIT_CHILDFATAL);
+    }
+
+    ap_run_child_init(pchild, ap_server_conf);
+
+    /* done with init critical section */
+
+    /* Just use the standard apr_setup_signal_thread to block all signals
+     * from being received.  The child processes no longer use signals for
+     * any communication with the parent process.
+     */
+    rv = apr_setup_signal_thread();
+    if (rv != APR_SUCCESS) {
+        ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf,
+                     "Couldn't initialize signal thread");
+        clean_child_exit(APEXIT_CHILDFATAL);
+    }
+
+    if (ap_max_requests_per_child) {
+        requests_this_child = ap_max_requests_per_child;
+    }
+    else {
+        /* coding a value of zero means infinity */
+        requests_this_child = INT_MAX;
+    }
+
+    /* Setup worker threads */
+
+    /* clear the storage; we may not create all our threads immediately,
+     * and we want a 0 entry to indicate a thread which was not created
+     */
+    threads = (apr_thread_t **) calloc(1,
+                                       sizeof(apr_thread_t *) *
+                                       ap_threads_per_child);
+    if (threads == NULL) {
+        ap_log_error(APLOG_MARK, APLOG_ALERT, errno, ap_server_conf,
+                     "malloc: out of memory");
+        clean_child_exit(APEXIT_CHILDFATAL);
+    }
+
+    ts = (thread_starter *) apr_palloc(pchild, sizeof(*ts));
+
+    apr_threadattr_create(&thread_attr, pchild);
+    /* 0 means PTHREAD_CREATE_JOINABLE */
+    apr_threadattr_detach_set(thread_attr, 0);
+
+    if (ap_thread_stacksize != 0) {
+        apr_threadattr_stacksize_set(thread_attr, ap_thread_stacksize);
+    }
+
+    ts->threads = threads;
+    ts->listener = NULL;
+    ts->child_num_arg = child_num_arg;
+    ts->threadattr = thread_attr;
+
+    rv = apr_thread_create(&start_thread_id, thread_attr, start_threads,
+                           ts, pchild);
+    if (rv != APR_SUCCESS) {
+        ap_log_error(APLOG_MARK, APLOG_ALERT, rv, ap_server_conf,
+                     "apr_thread_create: unable to create worker thread");
+        /* let the parent decide how bad this really is */
+        clean_child_exit(APEXIT_CHILDSICK);
+    }
+
+    mpm_state = AP_MPMQ_RUNNING;
+
+    /* If we are only running in one_process mode, we will want to
+     * still handle signals. */
+    if (one_process) {
+        /* Block until we get a terminating signal. */
+        apr_signal_thread(check_signal);
+        /* make sure the start thread has finished; signal_threads()
+         * and join_workers() depend on that
+         */
+        /* XXX join_start_thread() won't be awakened if one of our
+         *     threads encounters a critical error and attempts to
+         *     shutdown this child
+         */
+        join_start_thread(start_thread_id);
+
+        /* helps us terminate a little more quickly than the dispatch of the
+         * signal thread; beats the Pipe of Death and the browsers
+         */
+        signal_threads(ST_UNGRACEFUL);
+
+        /* A terminating signal was received. Now join each of the
+         * workers to clean them up.
+         *   If the worker already exited, then the join frees
+         *   their resources and returns.
+         *   If the worker hasn't exited, then this blocks until
+         *   they have (then cleans up).
+         */
+        join_workers(ts->listener, threads);
+    }
+    else {                      /* !one_process */
+        /* remove SIGTERM from the set of blocked signals...  if one of
+         * the other threads in the process needs to take us down
+         * (e.g., for MaxRequestsPerChild) it will send us SIGTERM
+         */
+        unblock_signal(SIGTERM);
+        apr_signal(SIGTERM, dummy_signal_handler);
+        /* Watch for any messages from the parent over the POD */
+        while (1) {
+            rv = ap_mpm_pod_check(pod);
+            if (rv == AP_NORESTART) {
+                /* see if termination was triggered while we slept */
+                switch (terminate_mode) {
+                case ST_GRACEFUL:
+                    rv = AP_GRACEFUL;
+                    break;
+                case ST_UNGRACEFUL:
+                    rv = AP_RESTART;
+                    break;
+                }
+            }
+            if (rv == AP_GRACEFUL || rv == AP_RESTART) {
+                /* make sure the start thread has finished;
+                 * signal_threads() and join_workers depend on that
+                 */
+                join_start_thread(start_thread_id);
+                signal_threads(rv ==
+                               AP_GRACEFUL ? ST_GRACEFUL : ST_UNGRACEFUL);
+                break;
+            }
+        }
+
+        /* A terminating signal was received. Now join each of the
+         * workers to clean them up.
+         *   If the worker already exited, then the join frees
+         *   their resources and returns.
+         *   If the worker hasn't exited, then this blocks until
+         *   they have (then cleans up).
+         */
+        join_workers(ts->listener, threads);
+    }
+
+    free(threads);
+
+    clean_child_exit(resource_shortage ? APEXIT_CHILDSICK : 0);
+}
+
+static int make_child(server_rec * s, int slot)
+{
+    int pid;
+
+    if (slot + 1 > ap_max_daemons_limit) {
+        ap_max_daemons_limit = slot + 1;
+    }
+
+    if (one_process) {
+        set_signals();
+        ap_scoreboard_image->parent[slot].pid = getpid();
+        child_main(slot);
+    }
+
+    if ((pid = fork()) == -1) {
+        ap_log_error(APLOG_MARK, APLOG_ERR, errno, s,
+                     "fork: Unable to fork new process");
+
+        /* fork didn't succeed. Fix the scoreboard or else
+         * it will say SERVER_STARTING forever and ever
+         */
+        ap_update_child_status_from_indexes(slot, 0, SERVER_DEAD, NULL);
+
+        /* In case system resources are maxxed out, we don't want
+           Apache running away with the CPU trying to fork over and
+           over and over again. */
+        apr_sleep(apr_time_from_sec(10));
+
+        return -1;
+    }
+
+    if (!pid) {
+#ifdef HAVE_BINDPROCESSOR
+        /* By default, AIX binds to a single processor.  This bit unbinds
+         * children which will then bind to another CPU.
+         */
+        int status = bindprocessor(BINDPROCESS, (int) getpid(),
+                                   PROCESSOR_CLASS_ANY);
+        if (status != OK)
+            ap_log_error(APLOG_MARK, APLOG_WARNING, errno,
+                         ap_server_conf,
+                         "processor unbind failed %d", status);
+#endif
+        RAISE_SIGSTOP(MAKE_CHILD);
+
+        apr_signal(SIGTERM, just_die);
+        child_main(slot);
+
+        clean_child_exit(0);
+    }
+    /* else */
+    ap_scoreboard_image->parent[slot].quiescing = 0;
+    ap_scoreboard_image->parent[slot].pid = pid;
+    return 0;
+}
+
+/* start up a bunch of children */
+static void startup_children(int number_to_start)
+{
+    int i;
+
+    for (i = 0; number_to_start && i < ap_daemons_limit; ++i) {
+        if (ap_scoreboard_image->parent[i].pid != 0) {
+            continue;
+        }
+        if (make_child(ap_server_conf, i) < 0) {
+            break;
+        }
+        --number_to_start;
+    }
+}
+
+
+/*
+ * idle_spawn_rate is the number of children that will be spawned on the
+ * next maintenance cycle if there aren't enough idle servers.  It is
+ * doubled up to MAX_SPAWN_RATE, and reset only when a cycle goes by
+ * without the need to spawn.
+ */
+static int idle_spawn_rate = 1;
+#ifndef MAX_SPAWN_RATE
+#define MAX_SPAWN_RATE        (32)
+#endif
+static int hold_off_on_exponential_spawning;
+
+static void perform_idle_server_maintenance(void)
+{
+    int i, j;
+    int idle_thread_count;
+    worker_score *ws;
+    process_score *ps;
+    int free_length;
+    int totally_free_length = 0;
+    int free_slots[MAX_SPAWN_RATE];
+    int last_non_dead;
+    int total_non_dead;
+    int active_thread_count = 0;
+
+    /* initialize the free_list */
+    free_length = 0;
+
+    idle_thread_count = 0;
+    last_non_dead = -1;
+    total_non_dead = 0;
+
+    for (i = 0; i < ap_daemons_limit; ++i) {
+        /* Initialization to satisfy the compiler. It doesn't know
+         * that ap_threads_per_child is always > 0 */
+        int status = SERVER_DEAD;
+        int any_dying_threads = 0;
+        int any_dead_threads = 0;
+        int all_dead_threads = 1;
+
+        if (i >= ap_max_daemons_limit
+            && totally_free_length == idle_spawn_rate)
+            break;
+        ps = &ap_scoreboard_image->parent[i];
+        for (j = 0; j < ap_threads_per_child; j++) {
+            ws = &ap_scoreboard_image->servers[i][j];
+            status = ws->status;
+
+            /* XXX any_dying_threads is probably no longer needed    GLA */
+            any_dying_threads = any_dying_threads ||
+                (status == SERVER_GRACEFUL);
+            any_dead_threads = any_dead_threads || (status == SERVER_DEAD);
+            all_dead_threads = all_dead_threads &&
+                (status == SERVER_DEAD || status == SERVER_GRACEFUL);
+
+            /* We consider a starting server as idle because we started it
+             * at least a cycle ago, and if it still hasn't finished starting
+             * then we're just going to swamp things worse by forking more.
+             * So we hopefully won't need to fork more if we count it.
+             * This depends on the ordering of SERVER_READY and SERVER_STARTING.
+             */
+            if (ps->pid != 0) { /* XXX just set all_dead_threads in outer
+                                   for loop if no pid?  not much else matters */
+                if (status <= SERVER_READY &&
+                        !ps->quiescing && ps->generation == ap_my_generation) {
+                    ++idle_thread_count;
+                }
+                if (status >= SERVER_READY && status < SERVER_GRACEFUL) {
+                    ++active_thread_count;
+                }
+            }
+        }
+        if (any_dead_threads
+            && totally_free_length < idle_spawn_rate
+            && free_length < MAX_SPAWN_RATE
+            && (!ps->pid      /* no process in the slot */
+                  || ps->quiescing)) {  /* or at least one is going away */
+            if (all_dead_threads) {
+                /* great! we prefer these, because the new process can
+                 * start more threads sooner.  So prioritize this slot
+                 * by putting it ahead of any slots with active threads.
+                 *
+                 * first, make room by moving a slot that's potentially still
+                 * in use to the end of the array
+                 */
+                free_slots[free_length] = free_slots[totally_free_length];
+                free_slots[totally_free_length++] = i;
+            }
+            else {
+                /* slot is still in use - back of the bus
+                 */
+                free_slots[free_length] = i;
+            }
+            ++free_length;
+        }
+        /* XXX if (!ps->quiescing)     is probably more reliable  GLA */
+        if (!any_dying_threads) {
+            last_non_dead = i;
+            ++total_non_dead;
+        }
+    }
+
+    if (sick_child_detected) {
+        if (active_thread_count > 0) {
+            /* some child processes appear to be working.  don't kill the
+             * whole server.
+             */
+            sick_child_detected = 0;
+        }
+        else {
+            /* looks like a basket case.  give up.
+             */
+            shutdown_pending = 1;
+            child_fatal = 1;
+            ap_log_error(APLOG_MARK, APLOG_ALERT, 0,
+                         ap_server_conf,
+                         "No active workers found..."
+                         " Apache is exiting!");
+            /* the child already logged the failure details */
+            return;
+        }
+    }
+
+    ap_max_daemons_limit = last_non_dead + 1;
+
+    if (idle_thread_count > max_spare_threads) {
+        /* Kill off one child */
+        ap_mpm_pod_signal(pod, TRUE);
+        idle_spawn_rate = 1;
+    }
+    else if (idle_thread_count < min_spare_threads) {
+        /* terminate the free list */
+        if (free_length == 0) {
+            /* only report this condition once */
+            static int reported = 0;
+
+            if (!reported) {
+                ap_log_error(APLOG_MARK, APLOG_ERR, 0,
+                             ap_server_conf,
+                             "server reached MaxClients setting, consider"
+                             " raising the MaxClients setting");
+                reported = 1;
+            }
+            idle_spawn_rate = 1;
+        }
+        else {
+            if (free_length > idle_spawn_rate) {
+                free_length = idle_spawn_rate;
+            }
+            if (idle_spawn_rate >= 8) {
+                ap_log_error(APLOG_MARK, APLOG_INFO, 0,
+                             ap_server_conf,
+                             "server seems busy, (you may need "
+                             "to increase StartServers, ThreadsPerChild "
+                             "or Min/MaxSpareThreads), "
+                             "spawning %d children, there are around %d idle "
+                             "threads, and %d total children", free_length,
+                             idle_thread_count, total_non_dead);
+            }
+            for (i = 0; i < free_length; ++i) {
+                make_child(ap_server_conf, free_slots[i]);
+            }
+            /* the next time around we want to spawn twice as many if this
+             * wasn't good enough, but not if we've just done a graceful
+             */
+            if (hold_off_on_exponential_spawning) {
+                --hold_off_on_exponential_spawning;
+            }
+            else if (idle_spawn_rate < MAX_SPAWN_RATE) {
+                idle_spawn_rate *= 2;
+            }
+        }
+    }
+    else {
+        idle_spawn_rate = 1;
+    }
+}
+
+static void server_main_loop(int remaining_children_to_start)
+{
+    int child_slot;
+    apr_exit_why_e exitwhy;
+    int status, processed_status;
+    apr_proc_t pid;
+    int i;
+
+    while (!restart_pending && !shutdown_pending) {
+        ap_wait_or_timeout(&exitwhy, &status, &pid, pconf);
+
+        if (pid.pid != -1) {
+            processed_status = ap_process_child_status(&pid, exitwhy, status);
+            if (processed_status == APEXIT_CHILDFATAL) {
+                shutdown_pending = 1;
+                child_fatal = 1;
+                return;
+            }
+            else if (processed_status == APEXIT_CHILDSICK) {
+                /* tell perform_idle_server_maintenance to check into this
+                 * on the next timer pop
+                 */
+                sick_child_detected = 1;
+            }
+            /* non-fatal death... note that it's gone in the scoreboard. */
+            child_slot = find_child_by_pid(&pid);
+            if (child_slot >= 0) {
+                for (i = 0; i < ap_threads_per_child; i++)
+                    ap_update_child_status_from_indexes(child_slot, i,
+                                                        SERVER_DEAD,
+                                                        (request_rec *) NULL);
+
+                ap_scoreboard_image->parent[child_slot].pid = 0;
+                ap_scoreboard_image->parent[child_slot].quiescing = 0;
+                if (processed_status == APEXIT_CHILDSICK) {
+                    /* resource shortage, minimize the fork rate */
+                    idle_spawn_rate = 1;
+                }
+                else if (remaining_children_to_start
+                         && child_slot < ap_daemons_limit) {
+                    /* we're still doing a 1-for-1 replacement of dead
+                     * children with new children
+                     */
+                    make_child(ap_server_conf, child_slot);
+                    --remaining_children_to_start;
+                }
+#if APR_HAS_OTHER_CHILD
+            }
+            else if (apr_proc_other_child_alert(&pid, APR_OC_REASON_DEATH,
+                                                status) == 0) {
+                /* handled */
+#endif
+            }
+            else if (is_graceful) {
+                /* Great, we've probably just lost a slot in the
+                 * scoreboard.  Somehow we don't know about this child.
+                 */
+                ap_log_error(APLOG_MARK, APLOG_WARNING, 0,
+                             ap_server_conf,
+                             "long lost child came home! (pid %ld)",
+                             (long) pid.pid);
+            }
+            /* Don't perform idle maintenance when a child dies,
+             * only do it when there's a timeout.  Remember only a
+             * finite number of children can die, and it's pretty
+             * pathological for a lot to die suddenly.
+             */
+            continue;
+        }
+        else if (remaining_children_to_start) {
+            /* we hit a 1 second timeout in which none of the previous
+             * generation of children needed to be reaped... so assume
+             * they're all done, and pick up the slack if any is left.
+             */
+            startup_children(remaining_children_to_start);
+            remaining_children_to_start = 0;
+            /* In any event we really shouldn't do the code below because
+             * few of the servers we just started are in the IDLE state
+             * yet, so we'd mistakenly create an extra server.
+             */
+            continue;
+        }
+
+        perform_idle_server_maintenance();
+    }
+}
+
+int ap_mpm_run(apr_pool_t * _pconf, apr_pool_t * plog, server_rec * s)
+{
+    int remaining_children_to_start;
+
+    ap_log_pid(pconf, ap_pid_fname);
+
+    first_server_limit = server_limit;
+    first_thread_limit = thread_limit;
+
+    if (changed_limit_at_restart) {
+        ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s,
+                     "WARNING: Attempt to change ServerLimit or ThreadLimit "
+                     "ignored during restart");
+        changed_limit_at_restart = 0;
+    }
+
+    if (!is_graceful) {
+        if (ap_run_pre_mpm(s->process->pool, SB_SHARED) != OK) {
+            mpm_state = AP_MPMQ_STOPPING;
+            return 1;
+        }
+        /* fix the generation number in the global score; we just got a new,
+         * cleared scoreboard
+         */
+        ap_scoreboard_image->global->running_generation = ap_my_generation;
+    }
+
+    set_signals();
+    /* Don't thrash... */
+    if (max_spare_threads < min_spare_threads + ap_threads_per_child)
+        max_spare_threads = min_spare_threads + ap_threads_per_child;
+
+    /* If we're doing a graceful_restart then we're going to see a lot
+     * of children exiting immediately when we get into the main loop
+     * below (because we just sent them AP_SIG_GRACEFUL).  This happens pretty
+     * rapidly... and for each one that exits we'll start a new one until
+     * we reach at least daemons_min_free.  But we may be permitted to
+     * start more than that, so we'll just keep track of how many we're
+     * supposed to start up without the 1 second penalty between each fork.
+     */
+    remaining_children_to_start = ap_daemons_to_start;
+    if (remaining_children_to_start > ap_daemons_limit) {
+        remaining_children_to_start = ap_daemons_limit;
+    }
+    if (!is_graceful) {
+        startup_children(remaining_children_to_start);
+        remaining_children_to_start = 0;
+    }
+    else {
+        /* give the system some time to recover before kicking into
+         * exponential mode */
+        hold_off_on_exponential_spawning = 10;
+    }
+
+    ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, ap_server_conf,
+                 "%s configured -- resuming normal operations",
+                 ap_get_server_version());
+    ap_log_error(APLOG_MARK, APLOG_INFO, 0, ap_server_conf,
+                 "Server built: %s", ap_get_server_built());
+
+    restart_pending = shutdown_pending = 0;
+    mpm_state = AP_MPMQ_RUNNING;
+
+    server_main_loop(remaining_children_to_start);
+    mpm_state = AP_MPMQ_STOPPING;
+
+    if (shutdown_pending && !is_graceful) {
+        /* Time to shut down:
+         * Kill child processes, tell them to call child_exit, etc...
+         */
+        ap_mpm_pod_killpg(pod, ap_daemons_limit, FALSE);
+        ap_reclaim_child_processes(1);  /* Start with SIGTERM */
+
+        if (!child_fatal) {
+            /* cleanup pid file on normal shutdown */
+            const char *pidfile = NULL;
+            pidfile = ap_server_root_relative(pconf, ap_pid_fname);
+            if (pidfile != NULL && unlink(pidfile) == 0)
+                ap_log_error(APLOG_MARK, APLOG_INFO, 0,
+                             ap_server_conf,
+                             "removed PID file %s (pid=%ld)",
+                             pidfile, (long) getpid());
+
+            ap_log_error(APLOG_MARK, APLOG_NOTICE, 0,
+                         ap_server_conf, "caught SIGTERM, shutting down");
+        }
+        return 1;
+    } else if (shutdown_pending) {
+        /* Time to gracefully shut down:
+         * Kill child processes, tell them to call child_exit, etc...
+         */
+        int active_children;
+        int index;
+        apr_time_t cutoff = 0;
+
+        /* Close our listeners, and then ask our children to do same */
+        ap_close_listeners();
+        ap_mpm_pod_killpg(pod, ap_daemons_limit, TRUE);
+        ap_relieve_child_processes();
+
+        if (!child_fatal) {
+            /* cleanup pid file on normal shutdown */
+            const char *pidfile = NULL;
+            pidfile = ap_server_root_relative (pconf, ap_pid_fname);
+            if ( pidfile != NULL && unlink(pidfile) == 0)
+                ap_log_error(APLOG_MARK, APLOG_INFO, 0,
+                             ap_server_conf,
+                             "removed PID file %s (pid=%ld)",
+                             pidfile, (long)getpid());
+
+            ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, ap_server_conf,
+                         "caught " AP_SIG_GRACEFUL_STOP_STRING
+                         ", shutting down gracefully");
+        }
+
+        if (ap_graceful_shutdown_timeout) {
+            cutoff = apr_time_now() +
+                     apr_time_from_sec(ap_graceful_shutdown_timeout);
+        }
+
+        /* Don't really exit until each child has finished */
+        shutdown_pending = 0;
+        do {
+            /* Pause for a second */
+            apr_sleep(apr_time_from_sec(1));
+
+            /* Relieve any children which have now exited */
+            ap_relieve_child_processes();
+
+            active_children = 0;
+            for (index = 0; index < ap_daemons_limit; ++index) {
+                if (MPM_CHILD_PID(index) != 0) {
+                    if (kill(MPM_CHILD_PID(index), 0) == 0) {
+                            active_children = 1;
+                            /* Having just one child is enough to stay around */
+                            break;
+                    }
+                }
+            }
+        } while (!shutdown_pending && active_children &&
+                 (!ap_graceful_shutdown_timeout || apr_time_now() < cutoff));
+
+        /* We might be here because we received SIGTERM, either
+         * way, try and make sure that all of our processes are
+         * really dead.
+         */
+        ap_mpm_pod_killpg(pod, ap_daemons_limit, FALSE);
+        ap_reclaim_child_processes(1);
+
+        return 1;
+    }
+
+    /* we've been told to restart */
+    apr_signal(SIGHUP, SIG_IGN);
+
+    if (one_process) {
+        /* not worth thinking about */
+        return 1;
+    }
+
+    /* advance to the next generation */
+    /* XXX: we really need to make sure this new generation number isn't in
+     * use by any of the children.
+     */
+    ++ap_my_generation;
+    ap_scoreboard_image->global->running_generation = ap_my_generation;
+
+    if (is_graceful) {
+        ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, ap_server_conf,
+                     AP_SIG_GRACEFUL_STRING
+                     " received.  Doing graceful restart");
+        /* wake up the children...time to die.  But we'll have more soon */
+        ap_mpm_pod_killpg(pod, ap_daemons_limit, TRUE);
+
+
+        /* This is mostly for debugging... so that we know what is still
+         * gracefully dealing with existing request.
+         */
+
+    }
+    else {
+        /* Kill 'em all.  Since the child acts the same on the parents SIGTERM
+         * and a SIGHUP, we may as well use the same signal, because some user
+         * pthreads are stealing signals from us left and right.
+         */
+        ap_mpm_pod_killpg(pod, ap_daemons_limit, FALSE);
+
+        ap_reclaim_child_processes(1);  /* Start with SIGTERM */
+        ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, ap_server_conf,
+                     "SIGHUP received.  Attempting to restart");
+    }
+
+    return 0;
+}
+
+/* This really should be a post_config hook, but the error log is already
+ * redirected by that point, so we need to do this in the open_logs phase.
+ */
+static int worker_open_logs(apr_pool_t * p, apr_pool_t * plog,
+                            apr_pool_t * ptemp, server_rec * s)
+{
+    apr_status_t rv;
+
+    pconf = p;
+    ap_server_conf = s;
+
+    if ((num_listensocks = ap_setup_listeners(ap_server_conf)) < 1) {
+        ap_log_error(APLOG_MARK, APLOG_ALERT | APLOG_STARTUP, 0,
+                     NULL, "no listening sockets available, shutting down");
+        return DONE;
+    }
+
+    if (!one_process) {
+        if ((rv = ap_mpm_pod_open(pconf, &pod))) {
+            ap_log_error(APLOG_MARK, APLOG_CRIT | APLOG_STARTUP, rv, NULL,
+                         "Could not open pipe-of-death.");
+            return DONE;
+        }
+    }
+    return OK;
+}
+
+static int worker_pre_config(apr_pool_t * pconf, apr_pool_t * plog,
+                             apr_pool_t * ptemp)
+{
+    static int restart_num = 0;
+    int no_detach, debug, foreground;
+    ap_directive_t *pdir;
+    ap_directive_t *max_clients = NULL;
+    apr_status_t rv;
+
+    mpm_state = AP_MPMQ_STARTING;
+
+    /* make sure that "ThreadsPerChild" gets set before "MaxClients" */
+    for (pdir = ap_conftree; pdir != NULL; pdir = pdir->next) {
+        if (strncasecmp(pdir->directive, "ThreadsPerChild", 15) == 0) {
+            if (!max_clients) {
+                /* we're in the clear, got ThreadsPerChild first */
+                break;
+            }
+            else {
+                /* now to swap the data */
+                ap_directive_t temp;
+
+                temp.directive = pdir->directive;
+                temp.args = pdir->args;
+                /* Make sure you don't change 'next', or you may get loops! */
+                /* XXX: first_child, parent, and data can never be set
+                 * for these directives, right? -aaron */
+                temp.filename = pdir->filename;
+                temp.line_num = pdir->line_num;
+
+                pdir->directive = max_clients->directive;
+                pdir->args = max_clients->args;
+                pdir->filename = max_clients->filename;
+                pdir->line_num = max_clients->line_num;
+
+                max_clients->directive = temp.directive;
+                max_clients->args = temp.args;
+                max_clients->filename = temp.filename;
+                max_clients->line_num = temp.line_num;
+                break;
+            }
+        }
+        else if (!max_clients
+                 && strncasecmp(pdir->directive, "MaxClients", 10) == 0) {
+            max_clients = pdir;
+        }
+    }
+
+    debug = ap_exists_config_define("DEBUG");
+
+    if (debug) {
+        foreground = one_process = 1;
+        no_detach = 0;
+    }
+    else {
+        one_process = ap_exists_config_define("ONE_PROCESS");
+        no_detach = ap_exists_config_define("NO_DETACH");
+        foreground = ap_exists_config_define("FOREGROUND");
+    }
+
+    /* sigh, want this only the second time around */
+    if (restart_num++ == 1) {
+        is_graceful = 0;
+        rv = apr_pollset_create(&event_pollset, 1, plog,
+                                APR_POLLSET_THREADSAFE);
+        if (rv != APR_SUCCESS) {
+            ap_log_error(APLOG_MARK, APLOG_CRIT, rv, NULL,
+                         "Couldn't create a Thread Safe Pollset. "
+                         "Is it supported on your platform?");
+            return HTTP_INTERNAL_SERVER_ERROR;
+        }
+        apr_pollset_destroy(event_pollset);
+
+        if (!one_process && !foreground) {
+            rv = apr_proc_detach(no_detach ? APR_PROC_DETACH_FOREGROUND
+                                 : APR_PROC_DETACH_DAEMONIZE);
+            if (rv != APR_SUCCESS) {
+                ap_log_error(APLOG_MARK, APLOG_CRIT, rv, NULL,
+                             "apr_proc_detach failed");
+                return HTTP_INTERNAL_SERVER_ERROR;
+            }
+        }
+        parent_pid = ap_my_pid = getpid();
+    }
+
+    unixd_pre_config(ptemp);
+    ap_listen_pre_config();
+    ap_daemons_to_start = DEFAULT_START_DAEMON;
+    min_spare_threads = DEFAULT_MIN_FREE_DAEMON * DEFAULT_THREADS_PER_CHILD;
+    max_spare_threads = DEFAULT_MAX_FREE_DAEMON * DEFAULT_THREADS_PER_CHILD;
+    ap_daemons_limit = server_limit;
+    ap_threads_per_child = DEFAULT_THREADS_PER_CHILD;
+    ap_pid_fname = DEFAULT_PIDLOG;
+    ap_lock_fname = DEFAULT_LOCKFILE;
+    ap_max_requests_per_child = DEFAULT_MAX_REQUESTS_PER_CHILD;
+    ap_extended_status = 0;
+#ifdef AP_MPM_WANT_SET_MAX_MEM_FREE
+    ap_max_mem_free = APR_ALLOCATOR_MAX_FREE_UNLIMITED;
+#endif
+
+    apr_cpystrn(ap_coredump_dir, ap_server_root, sizeof(ap_coredump_dir));
+
+    return OK;
+}
+
+static void event_hooks(apr_pool_t * p)
+{
+    /* The worker open_logs phase must run before the core's, or stderr
+     * will be redirected to a file, and the messages won't print to the
+     * console.
+     */
+    static const char *const aszSucc[] = { "core.c", NULL };
+    one_process = 0;
+
+    ap_hook_open_logs(worker_open_logs, NULL, aszSucc, APR_HOOK_MIDDLE);
+    /* we need to set the MPM state before other pre-config hooks use MPM query
+     * to retrieve it, so register as REALLY_FIRST
+     */
+    ap_hook_pre_config(worker_pre_config, NULL, NULL, APR_HOOK_REALLY_FIRST);
+}
+
+static const char *set_daemons_to_start(cmd_parms *cmd, void *dummy,
+                                        const char *arg)
+{
+    const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
+    if (err != NULL) {
+        return err;
+    }
+
+    ap_daemons_to_start = atoi(arg);
+    return NULL;
+}
+
+static const char *set_min_spare_threads(cmd_parms * cmd, void *dummy,
+                                         const char *arg)
+{
+    const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
+    if (err != NULL) {
+        return err;
+    }
+
+    min_spare_threads = atoi(arg);
+    if (min_spare_threads <= 0) {
+        ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL,
+                     "WARNING: detected MinSpareThreads set to non-positive.");
+        ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL,
+                     "Resetting to 1 to avoid almost certain Apache failure.");
+        ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL,
+                     "Please read the documentation.");
+        min_spare_threads = 1;
+    }
+
+    return NULL;
+}
+
+static const char *set_max_spare_threads(cmd_parms * cmd, void *dummy,
+                                         const char *arg)
+{
+    const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
+    if (err != NULL) {
+        return err;
+    }
+
+    max_spare_threads = atoi(arg);
+    return NULL;
+}
+
+static const char *set_max_clients(cmd_parms * cmd, void *dummy,
+                                   const char *arg)
+{
+    int max_clients;
+    const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
+    if (err != NULL) {
+        return err;
+    }
+
+    /* It is ok to use ap_threads_per_child here because we are
+     * sure that it gets set before MaxClients in the pre_config stage. */
+    max_clients = atoi(arg);
+    if (max_clients < ap_threads_per_child) {
+        ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL,
+                     "WARNING: MaxClients (%d) must be at least as large",
+                     max_clients);
+        ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL,
+                     " as ThreadsPerChild (%d). Automatically",
+                     ap_threads_per_child);
+        ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL,
+                     " increasing MaxClients to %d.", ap_threads_per_child);
+        max_clients = ap_threads_per_child;
+    }
+    ap_daemons_limit = max_clients / ap_threads_per_child;
+    if ((max_clients > 0) && (max_clients % ap_threads_per_child)) {
+        ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL,
+                     "WARNING: MaxClients (%d) is not an integer multiple",
+                     max_clients);
+        ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL,
+                     " of ThreadsPerChild (%d), lowering MaxClients to %d",
+                     ap_threads_per_child,
+                     ap_daemons_limit * ap_threads_per_child);
+        ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL,
+                     " for a maximum of %d child processes,",
+                     ap_daemons_limit);
+        max_clients = ap_daemons_limit * ap_threads_per_child;
+    }
+    if (ap_daemons_limit > server_limit) {
+       ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL,
+                    "WARNING: MaxClients of %d would require %d servers,",
+                    max_clients, ap_daemons_limit);
+       ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL,
+                    " and would exceed the ServerLimit value of %d.",
+                    server_limit);
+       ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL,
+                    " Automatically lowering MaxClients to %d.  To increase,",
+                    server_limit * ap_threads_per_child);
+       ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL,
+                    " please see the ServerLimit directive.");
+       ap_daemons_limit = server_limit;
+    }
+    else if (ap_daemons_limit < 1) {
+        ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL,
+                     "WARNING: Require MaxClients > 0, setting to 1");
+        ap_daemons_limit = 1;
+    }
+    return NULL;
+}
+
+static const char *set_threads_per_child(cmd_parms * cmd, void *dummy,
+                                         const char *arg)
+{
+    const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
+    if (err != NULL) {
+        return err;
+    }
+
+    ap_threads_per_child = atoi(arg);
+    if (ap_threads_per_child > thread_limit) {
+        ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL,
+                     "WARNING: ThreadsPerChild of %d exceeds ThreadLimit "
+                     "value of %d", ap_threads_per_child, thread_limit);
+        ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL,
+                     "threads, lowering ThreadsPerChild to %d. To increase, "
+                     "please see the", thread_limit);
+        ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL,
+                     " ThreadLimit directive.");
+        ap_threads_per_child = thread_limit;
+    }
+    else if (ap_threads_per_child < 1) {
+        ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL,
+                     "WARNING: Require ThreadsPerChild > 0, setting to 1");
+        ap_threads_per_child = 1;
+    }
+    return NULL;
+}
+static const char *set_server_limit (cmd_parms *cmd, void *dummy, const char *arg)
+{
+    int tmp_server_limit;
+
+    const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
+    if (err != NULL) {
+        return err;
+    }
+
+    tmp_server_limit = atoi(arg);
+    /* you cannot change ServerLimit across a restart; ignore
+     * any such attempts
+     */
+    if (first_server_limit &&
+        tmp_server_limit != server_limit) {
+        /* how do we log a message?  the error log is a bit bucket at this
+         * point; we'll just have to set a flag so that ap_mpm_run()
+         * logs a warning later
+         */
+        changed_limit_at_restart = 1;
+        return NULL;
+    }
+    server_limit = tmp_server_limit;
+
+    if (server_limit > MAX_SERVER_LIMIT) {
+       ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL,
+                    "WARNING: ServerLimit of %d exceeds compile time limit "
+                    "of %d servers,", server_limit, MAX_SERVER_LIMIT);
+       ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL,
+                    " lowering ServerLimit to %d.", MAX_SERVER_LIMIT);
+       server_limit = MAX_SERVER_LIMIT;
+    }
+    else if (server_limit < 1) {
+        ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL,
+                     "WARNING: Require ServerLimit > 0, setting to 1");
+        server_limit = 1;
+    }
+    return NULL;
+}
+
+static const char *set_thread_limit(cmd_parms * cmd, void *dummy,
+                                    const char *arg)
+{
+    int tmp_thread_limit;
+
+    const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
+    if (err != NULL) {
+        return err;
+    }
+
+    tmp_thread_limit = atoi(arg);
+    /* you cannot change ThreadLimit across a restart; ignore
+     * any such attempts
+     */
+    if (first_thread_limit && tmp_thread_limit != thread_limit) {
+        /* how do we log a message?  the error log is a bit bucket at this
+         * point; we'll just have to set a flag so that ap_mpm_run()
+         * logs a warning later
+         */
+        changed_limit_at_restart = 1;
+        return NULL;
+    }
+    thread_limit = tmp_thread_limit;
+
+    if (thread_limit > MAX_THREAD_LIMIT) {
+        ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL,
+                     "WARNING: ThreadLimit of %d exceeds compile time limit "
+                     "of %d servers,", thread_limit, MAX_THREAD_LIMIT);
+        ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL,
+                     " lowering ThreadLimit to %d.", MAX_THREAD_LIMIT);
+        thread_limit = MAX_THREAD_LIMIT;
+    }
+    else if (thread_limit < 1) {
+        ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL,
+                     "WARNING: Require ThreadLimit > 0, setting to 1");
+        thread_limit = 1;
+    }
+    return NULL;
+}
+
+static const command_rec event_cmds[] = {
+    UNIX_DAEMON_COMMANDS,
+    LISTEN_COMMANDS,
+    AP_INIT_TAKE1("StartServers", set_daemons_to_start, NULL, RSRC_CONF,
+                  "Number of child processes launched at server startup"),
+    AP_INIT_TAKE1("ServerLimit", set_server_limit, NULL, RSRC_CONF,
+                  "Maximum number of child processes for this run of Apache"),
+    AP_INIT_TAKE1("MinSpareThreads", set_min_spare_threads, NULL, RSRC_CONF,
+                  "Minimum number of idle threads, to handle request spikes"),
+    AP_INIT_TAKE1("MaxSpareThreads", set_max_spare_threads, NULL, RSRC_CONF,
+                  "Maximum number of idle threads"),
+    AP_INIT_TAKE1("MaxClients", set_max_clients, NULL, RSRC_CONF,
+                  "Maximum number of threads alive at the same time"),
+    AP_INIT_TAKE1("ThreadsPerChild", set_threads_per_child, NULL, RSRC_CONF,
+                  "Number of threads each child creates"),
+    AP_INIT_TAKE1("ThreadLimit", set_thread_limit, NULL, RSRC_CONF,
+                  "Maximum number of worker threads per child process for this "
+                  "run of Apache - Upper limit for ThreadsPerChild"),
+    AP_GRACEFUL_SHUTDOWN_TIMEOUT_COMMAND,
+    {NULL}
+};
+
+module AP_MODULE_DECLARE_DATA mpm_event_module = {
+    MPM20_MODULE_STUFF,
+    ap_mpm_rewrite_args,        /* hook to run before apache parses args */
+    NULL,                       /* create per-directory config structure */
+    NULL,                       /* merge per-directory config structures */
+    NULL,                       /* create per-server config structure */
+    NULL,                       /* merge per-server config structures */
+    event_cmds,                 /* command apr_table_t */
+    event_hooks                 /* register_hooks */
+};
diff --git a/server/mpm/experimental/event/fdqueue.c b/server/mpm/experimental/event/fdqueue.c
new file mode 100644
index 00000000..51952ced
--- /dev/null
+++ b/server/mpm/experimental/event/fdqueue.c
@@ -0,0 +1,420 @@
+/* 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 "fdqueue.h"
+#include "apr_atomic.h"
+
+typedef struct recycled_pool
+{
+    apr_pool_t *pool;
+    struct recycled_pool *next;
+} recycled_pool;
+
+struct fd_queue_info_t
+{
+    apr_int32_t idlers;      /**
+                                  * 0 or positive: number of idle worker threads
+                              * negative: number of threads blocked waiting
+                              *           for an idle worker
+                              */
+    apr_thread_mutex_t *idlers_mutex;
+    apr_thread_cond_t *wait_for_idler;
+    int terminated;
+    int max_idlers;
+    recycled_pool *recycled_pools;
+};
+
+static apr_status_t queue_info_cleanup(void *data_)
+{
+    fd_queue_info_t *qi = data_;
+    apr_thread_cond_destroy(qi->wait_for_idler);
+    apr_thread_mutex_destroy(qi->idlers_mutex);
+
+    /* Clean up any pools in the recycled list */
+    for (;;) {
+        struct recycled_pool *first_pool = qi->recycled_pools;
+        if (first_pool == NULL) {
+            break;
+        }
+        if (apr_atomic_casptr
+            ((volatile void **) &(qi->recycled_pools), first_pool->next,
+             first_pool) == first_pool) {
+            apr_pool_destroy(first_pool->pool);
+        }
+    }
+
+    return APR_SUCCESS;
+}
+
+apr_status_t ap_queue_info_create(fd_queue_info_t ** queue_info,
+                                  apr_pool_t * pool, int max_idlers)
+{
+    apr_status_t rv;
+    fd_queue_info_t *qi;
+
+    qi = apr_palloc(pool, sizeof(*qi));
+    memset(qi, 0, sizeof(*qi));
+
+    rv = apr_thread_mutex_create(&qi->idlers_mutex, APR_THREAD_MUTEX_DEFAULT,
+                                 pool);
+    if (rv != APR_SUCCESS) {
+        return rv;
+    }
+    rv = apr_thread_cond_create(&qi->wait_for_idler, pool);
+    if (rv != APR_SUCCESS) {
+        return rv;
+    }
+    qi->recycled_pools = NULL;
+    qi->max_idlers = max_idlers;
+    apr_pool_cleanup_register(pool, qi, queue_info_cleanup,
+                              apr_pool_cleanup_null);
+
+    *queue_info = qi;
+
+    return APR_SUCCESS;
+}
+
+apr_status_t ap_queue_info_set_idle(fd_queue_info_t * queue_info,
+                                    apr_pool_t * pool_to_recycle)
+{
+    apr_status_t rv;
+    int prev_idlers;
+
+    ap_push_pool(queue_info, pool_to_recycle);
+
+    /* Atomically increment the count of idle workers */
+    prev_idlers = apr_atomic_inc32(&(queue_info->idlers));
+
+    /* If other threads are waiting on a worker, wake one up */
+    if (prev_idlers < 0) {
+        rv = apr_thread_mutex_lock(queue_info->idlers_mutex);
+        if (rv != APR_SUCCESS) {
+            AP_DEBUG_ASSERT(0);
+            return rv;
+        }
+        rv = apr_thread_cond_signal(queue_info->wait_for_idler);
+        if (rv != APR_SUCCESS) {
+            apr_thread_mutex_unlock(queue_info->idlers_mutex);
+            return rv;
+        }
+        rv = apr_thread_mutex_unlock(queue_info->idlers_mutex);
+        if (rv != APR_SUCCESS) {
+            return rv;
+        }
+    }
+
+    return APR_SUCCESS;
+}
+
+apr_status_t ap_queue_info_wait_for_idler(fd_queue_info_t * queue_info)
+{
+    apr_status_t rv;
+    int prev_idlers;
+
+    /* Atomically decrement the idle worker count, saving the old value */
+    prev_idlers = apr_atomic_add32(&(queue_info->idlers), -1);
+
+    /* Block if there weren't any idle workers */
+    if (prev_idlers <= 0) {
+        rv = apr_thread_mutex_lock(queue_info->idlers_mutex);
+        if (rv != APR_SUCCESS) {
+            AP_DEBUG_ASSERT(0);
+            apr_atomic_inc32(&(queue_info->idlers));    /* back out dec */
+            return rv;
+        }
+        /* Re-check the idle worker count to guard against a
+         * race condition.  Now that we're in the mutex-protected
+         * region, one of two things may have happened:
+         *   - If the idle worker count is still negative, the
+         *     workers are all still busy, so it's safe to
+         *     block on a condition variable.
+         *   - If the idle worker count is non-negative, then a
+         *     worker has become idle since the first check
+         *     of queue_info->idlers above.  It's possible
+         *     that the worker has also signaled the condition
+         *     variable--and if so, the listener missed it
+         *     because it wasn't yet blocked on the condition
+         *     variable.  But if the idle worker count is
+         *     now non-negative, it's safe for this function to
+         *     return immediately.
+         *
+         *     A negative value in queue_info->idlers tells how many
+         *     threads are waiting on an idle worker.
+         */
+        if (queue_info->idlers < 0) {
+            rv = apr_thread_cond_wait(queue_info->wait_for_idler,
+                                      queue_info->idlers_mutex);
+            if (rv != APR_SUCCESS) {
+                apr_status_t rv2;
+                AP_DEBUG_ASSERT(0);
+                rv2 = apr_thread_mutex_unlock(queue_info->idlers_mutex);
+                if (rv2 != APR_SUCCESS) {
+                    return rv2;
+                }
+                return rv;
+            }
+        }
+        rv = apr_thread_mutex_unlock(queue_info->idlers_mutex);
+        if (rv != APR_SUCCESS) {
+            return rv;
+        }
+    }
+
+    if (queue_info->terminated) {
+        return APR_EOF;
+    }
+    else {
+        return APR_SUCCESS;
+    }
+}
+
+
+void ap_push_pool(fd_queue_info_t * queue_info,
+                                    apr_pool_t * pool_to_recycle)
+{
+    /* If we have been given a pool to recycle, atomically link
+     * it into the queue_info's list of recycled pools
+     */
+    if (pool_to_recycle) {
+        struct recycled_pool *new_recycle;
+        new_recycle = (struct recycled_pool *) apr_palloc(pool_to_recycle,
+                                                          sizeof
+                                                          (*new_recycle));
+        new_recycle->pool = pool_to_recycle;
+        for (;;) {
+            new_recycle->next = queue_info->recycled_pools;
+            if (apr_atomic_casptr
+                ((volatile void **) &(queue_info->recycled_pools),
+                 new_recycle, new_recycle->next) == new_recycle->next) {
+                break;
+            }
+        }
+    }
+}
+
+void ap_pop_pool(apr_pool_t ** recycled_pool, fd_queue_info_t * queue_info)
+{
+    /* Atomically pop a pool from the recycled list */
+
+    /* This function is safe only as long as it is single threaded because
+     * it reaches into the queue and accesses "next" which can change.
+     * We are OK today because it is only called from the listener thread.
+     * cas-based pushes do not have the same limitation - any number can
+     * happen concurrently with a single cas-based pop.
+     */
+
+    *recycled_pool = NULL;
+
+
+    /* Atomically pop a pool from the recycled list */
+    for (;;) {
+        struct recycled_pool *first_pool = queue_info->recycled_pools;
+        if (first_pool == NULL) {
+            break;
+        }
+        if (apr_atomic_casptr
+            ((volatile void **) &(queue_info->recycled_pools),
+             first_pool->next, first_pool) == first_pool) {
+            *recycled_pool = first_pool->pool;
+            break;
+        }
+    }
+}
+
+apr_status_t ap_queue_info_term(fd_queue_info_t * queue_info)
+{
+    apr_status_t rv;
+    rv = apr_thread_mutex_lock(queue_info->idlers_mutex);
+    if (rv != APR_SUCCESS) {
+        return rv;
+    }
+    queue_info->terminated = 1;
+    apr_thread_cond_broadcast(queue_info->wait_for_idler);
+    return apr_thread_mutex_unlock(queue_info->idlers_mutex);
+}
+
+/**
+ * Detects when the fd_queue_t is full. This utility function is expected
+ * to be called from within critical sections, and is not threadsafe.
+ */
+#define ap_queue_full(queue) ((queue)->nelts == (queue)->bounds)
+
+/**
+ * Detects when the fd_queue_t is empty. This utility function is expected
+ * to be called from within critical sections, and is not threadsafe.
+ */
+#define ap_queue_empty(queue) ((queue)->nelts == 0)
+
+/**
+ * Callback routine that is called to destroy this
+ * fd_queue_t when its pool is destroyed.
+ */
+static apr_status_t ap_queue_destroy(void *data)
+{
+    fd_queue_t *queue = data;
+
+    /* Ignore errors here, we can't do anything about them anyway.
+     * XXX: We should at least try to signal an error here, it is
+     * indicative of a programmer error. -aaron */
+    apr_thread_cond_destroy(queue->not_empty);
+    apr_thread_mutex_destroy(queue->one_big_mutex);
+
+    return APR_SUCCESS;
+}
+
+/**
+ * Initialize the fd_queue_t.
+ */
+apr_status_t ap_queue_init(fd_queue_t * queue, int queue_capacity,
+                           apr_pool_t * a)
+{
+    int i;
+    apr_status_t rv;
+
+    if ((rv = apr_thread_mutex_create(&queue->one_big_mutex,
+                                      APR_THREAD_MUTEX_DEFAULT,
+                                      a)) != APR_SUCCESS) {
+        return rv;
+    }
+    if ((rv = apr_thread_cond_create(&queue->not_empty, a)) != APR_SUCCESS) {
+        return rv;
+    }
+
+    queue->data = apr_palloc(a, queue_capacity * sizeof(fd_queue_elem_t));
+    queue->bounds = queue_capacity;
+    queue->nelts = 0;
+
+    /* Set all the sockets in the queue to NULL */
+    for (i = 0; i < queue_capacity; ++i)
+        queue->data[i].sd = NULL;
+
+    apr_pool_cleanup_register(a, queue, ap_queue_destroy,
+                              apr_pool_cleanup_null);
+
+    return APR_SUCCESS;
+}
+
+/**
+ * Push a new socket onto the queue.
+ *
+ * precondition: ap_queue_info_wait_for_idler has already been called
+ *               to reserve an idle worker thread
+ */
+apr_status_t ap_queue_push(fd_queue_t * queue, apr_socket_t * sd,
+                           conn_state_t * cs, apr_pool_t * p)
+{
+    fd_queue_elem_t *elem;
+    apr_status_t rv;
+
+    if ((rv = apr_thread_mutex_lock(queue->one_big_mutex)) != APR_SUCCESS) {
+        return rv;
+    }
+
+    AP_DEBUG_ASSERT(!queue->terminated);
+    AP_DEBUG_ASSERT(!ap_queue_full(queue));
+
+    elem = &queue->data[queue->nelts];
+    elem->sd = sd;
+    elem->cs = cs;
+    elem->p = p;
+    queue->nelts++;
+
+    apr_thread_cond_signal(queue->not_empty);
+
+    if ((rv = apr_thread_mutex_unlock(queue->one_big_mutex)) != APR_SUCCESS) {
+        return rv;
+    }
+
+    return APR_SUCCESS;
+}
+
+/**
+ * Retrieves the next available socket from the queue. If there are no
+ * sockets available, it will block until one becomes available.
+ * Once retrieved, the socket is placed into the address specified by
+ * 'sd'.
+ */
+apr_status_t ap_queue_pop(fd_queue_t * queue, apr_socket_t ** sd,
+                          conn_state_t ** cs, apr_pool_t ** p)
+{
+    fd_queue_elem_t *elem;
+    apr_status_t rv;
+
+    if ((rv = apr_thread_mutex_lock(queue->one_big_mutex)) != APR_SUCCESS) {
+        return rv;
+    }
+
+    /* Keep waiting until we wake up and find that the queue is not empty. */
+    if (ap_queue_empty(queue)) {
+        if (!queue->terminated) {
+            apr_thread_cond_wait(queue->not_empty, queue->one_big_mutex);
+        }
+        /* If we wake up and it's still empty, then we were interrupted */
+        if (ap_queue_empty(queue)) {
+            rv = apr_thread_mutex_unlock(queue->one_big_mutex);
+            if (rv != APR_SUCCESS) {
+                return rv;
+            }
+            if (queue->terminated) {
+                return APR_EOF; /* no more elements ever again */
+            }
+            else {
+                return APR_EINTR;
+            }
+        }
+    }
+
+    elem = &queue->data[--queue->nelts];
+    *sd = elem->sd;
+    *cs = elem->cs;
+    *p = elem->p;
+#ifdef AP_DEBUG
+    elem->sd = NULL;
+    elem->p = NULL;
+#endif /* AP_DEBUG */
+
+    rv = apr_thread_mutex_unlock(queue->one_big_mutex);
+    return rv;
+}
+
+apr_status_t ap_queue_interrupt_all(fd_queue_t * queue)
+{
+    apr_status_t rv;
+
+    if ((rv = apr_thread_mutex_lock(queue->one_big_mutex)) != APR_SUCCESS) {
+        return rv;
+    }
+    apr_thread_cond_broadcast(queue->not_empty);
+    return apr_thread_mutex_unlock(queue->one_big_mutex);
+}
+
+apr_status_t ap_queue_term(fd_queue_t * queue)
+{
+    apr_status_t rv;
+
+    if ((rv = apr_thread_mutex_lock(queue->one_big_mutex)) != APR_SUCCESS) {
+        return rv;
+    }
+    /* we must hold one_big_mutex when setting this... otherwise,
+     * we could end up setting it and waking everybody up just after a
+     * would-be popper checks it but right before they block
+     */
+    queue->terminated = 1;
+    if ((rv = apr_thread_mutex_unlock(queue->one_big_mutex)) != APR_SUCCESS) {
+        return rv;
+    }
+    return ap_queue_interrupt_all(queue);
+}
diff --git a/server/mpm/experimental/event/fdqueue.h b/server/mpm/experimental/event/fdqueue.h
new file mode 100644
index 00000000..bd18adfd
--- /dev/null
+++ b/server/mpm/experimental/event/fdqueue.h
@@ -0,0 +1,82 @@
+/* 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.
+ */
+
+/**
+ * @file  event/fdqueue.h
+ * @brief fd queue declarations
+ *
+ * @addtogroup APACHE_MPM_EVENT
+ * @{
+ */
+
+#ifndef FDQUEUE_H
+#define FDQUEUE_H
+#include "httpd.h"
+#include <stdlib.h>
+#if APR_HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+#include <apr_thread_mutex.h>
+#include <apr_thread_cond.h>
+#include <sys/types.h>
+#if APR_HAVE_SYS_SOCKET_H
+#include <sys/socket.h>
+#endif
+#include <apr_errno.h>
+
+typedef struct fd_queue_info_t fd_queue_info_t;
+
+apr_status_t ap_queue_info_create(fd_queue_info_t ** queue_info,
+                                  apr_pool_t * pool, int max_idlers);
+apr_status_t ap_queue_info_set_idle(fd_queue_info_t * queue_info,
+                                    apr_pool_t * pool_to_recycle);
+apr_status_t ap_queue_info_wait_for_idler(fd_queue_info_t * queue_info);
+apr_status_t ap_queue_info_term(fd_queue_info_t * queue_info);
+
+struct fd_queue_elem_t
+{
+    apr_socket_t *sd;
+    apr_pool_t *p;
+    conn_state_t *cs;
+};
+typedef struct fd_queue_elem_t fd_queue_elem_t;
+
+struct fd_queue_t
+{
+    fd_queue_elem_t *data;
+    int nelts;
+    int bounds;
+    apr_thread_mutex_t *one_big_mutex;
+    apr_thread_cond_t *not_empty;
+    int terminated;
+};
+typedef struct fd_queue_t fd_queue_t;
+
+void ap_pop_pool(apr_pool_t ** recycled_pool, fd_queue_info_t * queue_info);
+void ap_push_pool(fd_queue_info_t * queue_info,          
+                                    apr_pool_t * pool_to_recycle);
+
+apr_status_t ap_queue_init(fd_queue_t * queue, int queue_capacity,
+                           apr_pool_t * a);
+apr_status_t ap_queue_push(fd_queue_t * queue, apr_socket_t * sd,
+                           conn_state_t * cs, apr_pool_t * p);
+apr_status_t ap_queue_pop(fd_queue_t * queue, apr_socket_t ** sd,
+                          conn_state_t ** cs, apr_pool_t ** p);
+apr_status_t ap_queue_interrupt_all(fd_queue_t * queue);
+apr_status_t ap_queue_term(fd_queue_t * queue);
+
+#endif /* FDQUEUE_H */
+/** @} */
diff --git a/server/mpm/experimental/event/mpm.h b/server/mpm/experimental/event/mpm.h
new file mode 100644
index 00000000..cf4e61d9
--- /dev/null
+++ b/server/mpm/experimental/event/mpm.h
@@ -0,0 +1,62 @@
+/* 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.
+ */
+
+/**
+ * @file event/mpm.h
+ * @brief Unix Exent driven MPM
+ *
+ * @defgroup APACHE_MPM_EVENT Unix Event MPM
+ * @ingroup  APACHE_OS_UNIX APACHE_MPM
+ * @{
+ */
+
+#include "scoreboard.h"
+#include "unixd.h"
+
+#ifndef APACHE_MPM_EVENT_H
+#define APACHE_MPM_EVENT_H
+
+#define EVENT_MPM
+
+#define MPM_NAME "Event"
+
+#define AP_MPM_WANT_RECLAIM_CHILD_PROCESSES
+#define AP_MPM_WANT_WAIT_OR_TIMEOUT
+#define AP_MPM_WANT_PROCESS_CHILD_STATUS
+#define AP_MPM_WANT_SET_PIDFILE
+#define AP_MPM_WANT_SET_SCOREBOARD
+#define AP_MPM_WANT_SET_LOCKFILE
+#define AP_MPM_WANT_SET_MAX_REQUESTS
+#define AP_MPM_WANT_SET_COREDUMPDIR
+#define AP_MPM_WANT_SET_ACCEPT_LOCK_MECH
+#define AP_MPM_WANT_SIGNAL_SERVER
+#define AP_MPM_WANT_SET_MAX_MEM_FREE
+#define AP_MPM_WANT_SET_STACKSIZE
+#define AP_MPM_WANT_SET_GRACEFUL_SHUTDOWN
+#define AP_MPM_WANT_FATAL_SIGNAL_HANDLER
+#define AP_MPM_DISABLE_NAGLE_ACCEPTED_SOCK
+
+#define MPM_CHILD_PID(i) (ap_scoreboard_image->parent[i].pid)
+#define MPM_NOTE_CHILD_KILLED(i) (MPM_CHILD_PID(i) = 0)
+#define MPM_ACCEPT_FUNC unixd_accept
+
+extern int ap_threads_per_child;
+extern int ap_max_daemons_limit;
+extern server_rec *ap_server_conf;
+extern char ap_coredump_dir[MAX_STRING_LEN];
+
+#endif /* APACHE_MPM_EVENT_H */
+/** @} */
diff --git a/server/mpm/experimental/event/mpm_default.h b/server/mpm/experimental/event/mpm_default.h
new file mode 100644
index 00000000..c26ee714
--- /dev/null
+++ b/server/mpm/experimental/event/mpm_default.h
@@ -0,0 +1,79 @@
+/* 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.
+ */
+
+
+/**
+ * @file  event/mpm_default.h
+ * @brief Event MPM defaults
+ *
+ * @addtogroup APACHE_MPM_EVENT
+ * @{
+ */
+
+#ifndef APACHE_MPM_DEFAULT_H
+#define APACHE_MPM_DEFAULT_H
+
+/* Number of servers to spawn off by default --- also, if fewer than
+ * this free when the caretaker checks, it will spawn more.
+ */
+#ifndef DEFAULT_START_DAEMON
+#define DEFAULT_START_DAEMON 3
+#endif
+
+/* Maximum number of *free* server processes --- more than this, and
+ * they will die off.
+ */
+
+#ifndef DEFAULT_MAX_FREE_DAEMON
+#define DEFAULT_MAX_FREE_DAEMON 10
+#endif
+
+/* Minimum --- fewer than this, and more will be created */
+
+#ifndef DEFAULT_MIN_FREE_DAEMON
+#define DEFAULT_MIN_FREE_DAEMON 3
+#endif
+
+#ifndef DEFAULT_THREADS_PER_CHILD
+#define DEFAULT_THREADS_PER_CHILD 25
+#endif
+
+/* File used for accept locking, when we use a file */
+#ifndef DEFAULT_LOCKFILE
+#define DEFAULT_LOCKFILE DEFAULT_REL_RUNTIMEDIR "/accept.lock"
+#endif
+
+/* Where the main/parent process's pid is logged */
+#ifndef DEFAULT_PIDLOG
+#define DEFAULT_PIDLOG DEFAULT_REL_RUNTIMEDIR "/httpd.pid"
+#endif
+
+/*
+ * Interval, in microseconds, between scoreboard maintenance.
+ */
+#ifndef SCOREBOARD_MAINTENANCE_INTERVAL
+#define SCOREBOARD_MAINTENANCE_INTERVAL 1000000
+#endif
+
+/* Number of requests to try to handle in a single process.  If <= 0,
+ * the children don't die off.
+ */
+#ifndef DEFAULT_MAX_REQUESTS_PER_CHILD
+#define DEFAULT_MAX_REQUESTS_PER_CHILD 10000
+#endif
+
+#endif /* AP_MPM_DEFAULT_H */
+/** @} */
diff --git a/server/mpm/experimental/event/pod.c b/server/mpm/experimental/event/pod.c
new file mode 100644
index 00000000..5a9999f7
--- /dev/null
+++ b/server/mpm/experimental/event/pod.c
@@ -0,0 +1,109 @@
+/* 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 "pod.h"
+
+#if APR_HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+
+AP_DECLARE(apr_status_t) ap_mpm_pod_open(apr_pool_t * p, ap_pod_t ** pod)
+{
+    apr_status_t rv;
+
+    *pod = apr_palloc(p, sizeof(**pod));
+    rv = apr_file_pipe_create(&((*pod)->pod_in), &((*pod)->pod_out), p);
+    if (rv != APR_SUCCESS) {
+        return rv;
+    }
+/*
+    apr_file_pipe_timeout_set((*pod)->pod_in, 0);
+*/
+    (*pod)->p = p;
+
+    /* close these before exec. */
+    apr_file_inherit_unset((*pod)->pod_in);
+    apr_file_inherit_unset((*pod)->pod_out);
+
+    return APR_SUCCESS;
+}
+
+AP_DECLARE(int) ap_mpm_pod_check(ap_pod_t * pod)
+{
+    char c;
+    apr_os_file_t fd;
+    int rc;
+
+    /* we need to surface EINTR so we'll have to grab the
+     * native file descriptor and do the OS read() ourselves
+     */
+    apr_os_file_get(&fd, pod->pod_in);
+    rc = read(fd, &c, 1);
+    if (rc == 1) {
+        switch (c) {
+        case RESTART_CHAR:
+            return AP_RESTART;
+        case GRACEFUL_CHAR:
+            return AP_GRACEFUL;
+        }
+    }
+    return AP_NORESTART;
+}
+
+AP_DECLARE(apr_status_t) ap_mpm_pod_close(ap_pod_t * pod)
+{
+    apr_status_t rv;
+
+    rv = apr_file_close(pod->pod_out);
+    if (rv != APR_SUCCESS) {
+        return rv;
+    }
+
+    rv = apr_file_close(pod->pod_in);
+    if (rv != APR_SUCCESS) {
+        return rv;
+    }
+    return rv;
+}
+
+static apr_status_t pod_signal_internal(ap_pod_t * pod, int graceful)
+{
+    apr_status_t rv;
+    char char_of_death = graceful ? GRACEFUL_CHAR : RESTART_CHAR;
+    apr_size_t one = 1;
+
+    rv = apr_file_write(pod->pod_out, &char_of_death, &one);
+    if (rv != APR_SUCCESS) {
+        ap_log_error(APLOG_MARK, APLOG_WARNING, rv, ap_server_conf,
+                     "write pipe_of_death");
+    }
+    return rv;
+}
+
+AP_DECLARE(apr_status_t) ap_mpm_pod_signal(ap_pod_t * pod, int graceful)
+{
+    return pod_signal_internal(pod, graceful);
+}
+
+AP_DECLARE(void) ap_mpm_pod_killpg(ap_pod_t * pod, int num, int graceful)
+{
+    int i;
+    apr_status_t rv = APR_SUCCESS;
+
+    for (i = 0; i < num && rv == APR_SUCCESS; i++) {
+        rv = pod_signal_internal(pod, graceful);
+    }
+}
diff --git a/server/mpm/experimental/event/pod.h b/server/mpm/experimental/event/pod.h
new file mode 100644
index 00000000..78e2b9d7
--- /dev/null
+++ b/server/mpm/experimental/event/pod.h
@@ -0,0 +1,60 @@
+/* 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.
+ */
+
+/**
+ * @file  event/pod.h
+ * @brief pod definitions
+ *
+ * @addtogroup APACHE_MPM_EVENT
+ * @{
+ */
+
+#include "apr.h"
+#include "apr_strings.h"
+#define APR_WANT_STRFUNC
+#include "apr_want.h"
+
+#include "httpd.h"
+#include "http_config.h"
+#include "http_log.h"
+#include "http_main.h"
+#include "mpm.h"
+#include "mpm_common.h"
+#include "ap_mpm.h"
+#include "ap_listen.h"
+#include "mpm_default.h"
+
+#define RESTART_CHAR '$'
+#define GRACEFUL_CHAR '!'
+
+#define AP_RESTART  0
+#define AP_GRACEFUL 1
+
+typedef struct ap_pod_t ap_pod_t;
+
+struct ap_pod_t
+{
+    apr_file_t *pod_in;
+    apr_file_t *pod_out;
+    apr_pool_t *p;
+};
+
+AP_DECLARE(apr_status_t) ap_mpm_pod_open(apr_pool_t * p, ap_pod_t ** pod);
+AP_DECLARE(int) ap_mpm_pod_check(ap_pod_t * pod);
+AP_DECLARE(apr_status_t) ap_mpm_pod_close(ap_pod_t * pod);
+AP_DECLARE(apr_status_t) ap_mpm_pod_signal(ap_pod_t * pod, int graceful);
+AP_DECLARE(void) ap_mpm_pod_killpg(ap_pod_t * pod, int num, int graceful);
+/** @} */