Adding upstream version 2.4.56.upstream/2.4.56upstream

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

5 files changed, 4157 insertions, 0 deletions

diff --git a/server/mpm/event/Makefile.in b/server/mpm/event/Makefile.in
new file mode 100644
index 0000000..f34af9c
--- /dev/null
+++ b/server/mpm/event/Makefile.in
@@ -0,0 +1 @@
+include $(top_srcdir)/build/special.mk
diff --git a/server/mpm/event/config.m4 b/server/mpm/event/config.m4
new file mode 100644
index 0000000..c891c75
--- /dev/null
+++ b/server/mpm/event/config.m4
@@ -0,0 +1,15 @@
+AC_MSG_CHECKING(if event MPM supports this platform)
+if test $forking_mpms_supported != yes; then
+    AC_MSG_RESULT(no - This is not a forking platform)
+elif test $ac_cv_define_APR_HAS_THREADS != yes; then
+    AC_MSG_RESULT(no - APR does not support threads)
+elif test $have_threaded_sig_graceful != yes; then
+    AC_MSG_RESULT(no - SIG_GRACEFUL cannot be used with a threaded MPM)
+elif test $ac_cv_have_threadsafe_pollset != yes; then
+    AC_MSG_RESULT(no - APR_POLLSET_THREADSAFE is not supported)
+elif test $apr_has_skiplist != yes; then
+    AC_MSG_RESULT(no - APR skiplist is not available, need APR 1.5.x or later)
+else
+    AC_MSG_RESULT(yes)
+    APACHE_MPM_SUPPORTED(event, yes, yes)
+fi
diff --git a/server/mpm/event/config3.m4 b/server/mpm/event/config3.m4
new file mode 100644
index 0000000..09d3626
--- /dev/null
+++ b/server/mpm/event/config3.m4
@@ -0,0 +1,7 @@
+dnl ## XXX - Need a more thorough check of the proper flags to use
+
+APACHE_SUBST(MOD_MPM_EVENT_LDADD)
+
+APACHE_MPM_MODULE(event, $enable_mpm_event, event.lo,[
+    AC_CHECK_FUNCS(pthread_kill)
+], , [\$(MOD_MPM_EVENT_LDADD)])
diff --git a/server/mpm/event/event.c b/server/mpm/event/event.c
new file mode 100644
index 0000000..3672f44
--- /dev/null
+++ b/server/mpm/event/event.c
@@ -0,0 +1,4078 @@
+/* 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
+ * significant 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 Listening sockets,
+ * and all sockets that are in a Keep Alive status.
+ *
+ * The MPM assumes the underlying apr_pollset implementation 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 does not perform 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_poll.h"
+#include "apr_ring.h"
+#include "apr_queue.h"
+#include "apr_atomic.h"
+#define APR_WANT_STRFUNC
+#include "apr_want.h"
+#include "apr_version.h"
+
+#include <stdlib.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
+
+#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 "http_protocol.h"
+#include "ap_mpm.h"
+#include "mpm_common.h"
+#include "ap_listen.h"
+#include "scoreboard.h"
+#include "mpm_fdqueue.h"
+#include "mpm_default.h"
+#include "http_vhost.h"
+#include "unixd.h"
+#include "apr_skiplist.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
+
+#define MPM_CHILD_PID(i) (ap_scoreboard_image->parent[i].pid)
+
+#if !APR_VERSION_AT_LEAST(1,4,0)
+#define apr_time_from_msec(x) (x * 1000)
+#endif
+
+#ifndef MAX_SECS_TO_LINGER
+#define MAX_SECS_TO_LINGER 30
+#endif
+#define SECONDS_TO_LINGER  2
+
+/*
+ * Actual definitions of config globals
+ */
+
+#ifndef DEFAULT_WORKER_FACTOR
+#define DEFAULT_WORKER_FACTOR 2
+#endif
+#define WORKER_FACTOR_SCALE   16  /* scale factor to allow fractional values */
+static unsigned int worker_factor = DEFAULT_WORKER_FACTOR * WORKER_FACTOR_SCALE;
+    /* AsyncRequestWorkerFactor * 16 */
+
+static int threads_per_child = 0;           /* ThreadsPerChild */
+static int ap_daemons_to_start = 0;         /* StartServers */
+static int min_spare_threads = 0;           /* MinSpareThreads */
+static int max_spare_threads = 0;           /* MaxSpareThreads */
+static int active_daemons_limit = 0;        /* MaxRequestWorkers / ThreadsPerChild */
+static int max_workers = 0;                 /* MaxRequestWorkers */
+static int server_limit = 0;                /* ServerLimit */
+static int thread_limit = 0;                /* ThreadLimit */
+static int had_healthy_child = 0;
+static volatile int dying = 0;
+static volatile int workers_may_exit = 0;
+static volatile int start_thread_may_exit = 0;
+static volatile int listener_may_exit = 0;
+static int listener_is_wakeable = 0;        /* Pollset supports APR_POLLSET_WAKEABLE */
+static int num_listensocks = 0;
+static apr_int32_t conns_this_child;        /* MaxConnectionsPerChild, only access
+                                               in listener thread */
+static apr_uint32_t connection_count = 0;   /* Number of open connections */
+static apr_uint32_t lingering_count = 0;    /* Number of connections in lingering close */
+static apr_uint32_t suspended_count = 0;    /* Number of suspended connections */
+static apr_uint32_t clogged_count = 0;      /* Number of threads processing ssl conns */
+static apr_uint32_t threads_shutdown = 0;   /* Number of threads that have shutdown
+                                               early during graceful termination */
+static int resource_shortage = 0;
+static fd_queue_t *worker_queue;
+static fd_queue_info_t *worker_queue_info;
+
+static apr_thread_mutex_t *timeout_mutex;
+
+module AP_MODULE_DECLARE_DATA mpm_event_module;
+
+/* forward declare */
+struct event_srv_cfg_s;
+typedef struct event_srv_cfg_s event_srv_cfg;
+
+static apr_pollfd_t *listener_pollfd;
+
+/*
+ * The pollset for sockets that are in any of the timeout queues. Currently
+ * we use the timeout_mutex to make sure that connections are added/removed
+ * atomically to/from both event_pollset and a timeout queue. Otherwise
+ * some confusion can happen under high load if timeout queues and pollset
+ * get out of sync.
+ * XXX: It should be possible to make the lock unnecessary in many or even all
+ * XXX: cases.
+ */
+static apr_pollset_t *event_pollset;
+
+typedef struct event_conn_state_t event_conn_state_t;
+
+/*
+ * The chain of connections to be shutdown by a worker thread (deferred),
+ * linked list updated atomically.
+ */
+static event_conn_state_t *volatile defer_linger_chain;
+
+struct event_conn_state_t {
+    /** APR_RING of expiration timeouts */
+    APR_RING_ENTRY(event_conn_state_t) timeout_list;
+    /** the time when the entry was queued */
+    apr_time_t queue_timestamp;
+    /** connection record this struct refers to */
+    conn_rec *c;
+    /** request record (if any) this struct refers to */
+    request_rec *r;
+    /** server config this struct refers to */
+    event_srv_cfg *sc;
+    /** scoreboard handle for the conn_rec */
+    ap_sb_handle_t *sbh;
+    /** is the current conn_rec suspended?  (disassociated with
+     * a particular MPM thread; for suspend_/resume_connection
+     * hooks)
+     */
+    int suspended;
+    /** memory pool to allocate from */
+    apr_pool_t *p;
+    /** bucket allocator */
+    apr_bucket_alloc_t *bucket_alloc;
+    /** poll file descriptor information */
+    apr_pollfd_t pfd;
+    /** public parts of the connection state */
+    conn_state_t pub;
+    /** chaining in defer_linger_chain */
+    struct event_conn_state_t *chain;
+    /** Is lingering close from defer_lingering_close()? */
+    int deferred_linger;
+};
+
+APR_RING_HEAD(timeout_head_t, event_conn_state_t);
+
+struct timeout_queue {
+    struct timeout_head_t head;
+    apr_interval_time_t timeout;
+    apr_uint32_t count;         /* for this queue */
+    apr_uint32_t *total;        /* for all chained/related queues */
+    struct timeout_queue *next; /* chaining */
+};
+/*
+ * Several timeout queues that use different timeouts, so that we always can
+ * simply append to the end.
+ *   write_completion_q uses vhost's TimeOut
+ *   keepalive_q        uses vhost's KeepAliveTimeOut
+ *   linger_q           uses MAX_SECS_TO_LINGER
+ *   short_linger_q     uses SECONDS_TO_LINGER
+ */
+static struct timeout_queue *write_completion_q,
+                            *keepalive_q,
+                            *linger_q,
+                            *short_linger_q;
+static volatile apr_time_t  queues_next_expiry;
+
+/* Prevent extra poll/wakeup calls for timeouts close in the future (queues
+ * have the granularity of a second anyway).
+ * XXX: Wouldn't 0.5s (instead of 0.1s) be "enough"?
+ */
+#define TIMEOUT_FUDGE_FACTOR apr_time_from_msec(100)
+
+/*
+ * Macros for accessing struct timeout_queue.
+ * For TO_QUEUE_APPEND and TO_QUEUE_REMOVE, timeout_mutex must be held.
+ */
+static void TO_QUEUE_APPEND(struct timeout_queue *q, event_conn_state_t *el)
+{
+    apr_time_t elem_expiry;
+    apr_time_t next_expiry;
+
+    APR_RING_INSERT_TAIL(&q->head, el, event_conn_state_t, timeout_list);
+    ++*q->total;
+    ++q->count;
+
+    /* Cheaply update the global queues_next_expiry with the one of the
+     * first entry of this queue (oldest) if it expires before.
+     */
+    el = APR_RING_FIRST(&q->head);
+    elem_expiry = el->queue_timestamp + q->timeout;
+    next_expiry = queues_next_expiry;
+    if (!next_expiry || next_expiry > elem_expiry + TIMEOUT_FUDGE_FACTOR) {
+        queues_next_expiry = elem_expiry;
+        /* Unblock the poll()ing listener for it to update its timeout. */
+        if (listener_is_wakeable) {
+            apr_pollset_wakeup(event_pollset);
+        }
+    }
+}
+
+static void TO_QUEUE_REMOVE(struct timeout_queue *q, event_conn_state_t *el)
+{
+    APR_RING_REMOVE(el, timeout_list);
+    APR_RING_ELEM_INIT(el, timeout_list);
+    --*q->total;
+    --q->count;
+}
+
+static struct timeout_queue *TO_QUEUE_MAKE(apr_pool_t *p, apr_time_t t,
+                                           struct timeout_queue *ref)
+{
+    struct timeout_queue *q;
+                                           
+    q = apr_pcalloc(p, sizeof *q);
+    APR_RING_INIT(&q->head, event_conn_state_t, timeout_list);
+    q->total = (ref) ? ref->total : apr_pcalloc(p, sizeof *q->total);
+    q->timeout = t;
+
+    return q;
+}
+
+#define TO_QUEUE_ELEM_INIT(el) \
+    APR_RING_ELEM_INIT((el), timeout_list)
+
+/* The structure used to pass unique initialization info to each thread */
+typedef struct
+{
+    int pslot;  /* process slot */
+    int tslot;  /* worker slot of the thread */
+} 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;
+    void *baton;
+} listener_poll_type;
+
+/* data retained by event across load/unload of the module
+ * allocated on first call to pre-config hook; located on
+ * subsequent calls to pre-config hook
+ */
+typedef struct event_retained_data {
+    ap_unixd_mpm_retained_data *mpm;
+
+    int first_server_limit;
+    int first_thread_limit;
+    int sick_child_detected;
+    int maxclients_reported;
+    int near_maxclients_reported;
+    /*
+     * The max child slot ever assigned, preserved across restarts.  Necessary
+     * to deal with MaxRequestWorkers changes across AP_SIG_GRACEFUL restarts.
+     * We use this value to optimize routines that have to scan the entire
+     * scoreboard.
+     */
+    int max_daemon_used;
+
+    /*
+     * All running workers, active and shutting down, including those that
+     * may be left from before a graceful restart.
+     * Not kept up-to-date when shutdown is pending.
+     */
+    int total_daemons;
+    /*
+     * Workers that still active, i.e. are not shutting down gracefully.
+     */
+    int active_daemons;
+    /*
+     * 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
+     * maintained per listeners bucket, doubled up to MAX_SPAWN_RATE, and
+     * reset only when a cycle goes by without the need to spawn.
+     */
+    int *idle_spawn_rate;
+#ifndef MAX_SPAWN_RATE
+#define MAX_SPAWN_RATE        (32)
+#endif
+    int hold_off_on_exponential_spawning;
+} event_retained_data;
+static event_retained_data *retained;
+ 
+typedef struct event_child_bucket {
+    ap_pod_t *pod;
+    ap_listen_rec *listeners;
+} event_child_bucket;
+static event_child_bucket *all_buckets, /* All listeners buckets */
+                          *my_bucket;   /* Current child bucket */
+
+struct event_srv_cfg_s {
+    struct timeout_queue *wc_q,
+                         *ka_q;
+};
+
+#define ID_FROM_CHILD_THREAD(c, t)    ((c * thread_limit) + t)
+
+/* The event 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 apr_pool_t *pruntime;    /* Pool for MPM threads 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;
+
+static int ap_child_slot;       /* Current child process slot in scoreboard */
+
+/* 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 volatile apr_uint32_t listensocks_disabled;
+
+static void disable_listensocks(void)
+{
+    int i;
+    if (apr_atomic_cas32(&listensocks_disabled, 1, 0) != 0) {
+        return;
+    }
+    if (event_pollset) {
+        for (i = 0; i < num_listensocks; i++) {
+            apr_pollset_remove(event_pollset, &listener_pollfd[i]);
+        }
+    }
+    ap_scoreboard_image->parent[ap_child_slot].not_accepting = 1;
+}
+
+static void enable_listensocks(void)
+{
+    int i;
+    if (listener_may_exit
+            || apr_atomic_cas32(&listensocks_disabled, 0, 1) != 1) {
+        return;
+    }
+    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf, APLOGNO(00457)
+                 "Accepting new connections again: "
+                 "%u active conns (%u lingering/%u clogged/%u suspended), "
+                 "%u idle workers",
+                 apr_atomic_read32(&connection_count),
+                 apr_atomic_read32(&lingering_count),
+                 apr_atomic_read32(&clogged_count),
+                 apr_atomic_read32(&suspended_count),
+                 ap_queue_info_num_idlers(worker_queue_info));
+    for (i = 0; i < num_listensocks; i++)
+        apr_pollset_add(event_pollset, &listener_pollfd[i]);
+    /*
+     * XXX: This is not yet optimal. If many workers suddenly become available,
+     * XXX: the parent may kill some processes off too soon.
+     */
+    ap_scoreboard_image->parent[ap_child_slot].not_accepting = 0;
+}
+
+static APR_INLINE apr_uint32_t listeners_disabled(void)
+{
+    return apr_atomic_read32(&listensocks_disabled);
+}
+
+static APR_INLINE int connections_above_limit(int *busy)
+{
+    apr_uint32_t i_count = ap_queue_info_num_idlers(worker_queue_info);
+    if (i_count > 0) {
+        apr_uint32_t c_count = apr_atomic_read32(&connection_count);
+        apr_uint32_t l_count = apr_atomic_read32(&lingering_count);
+        if (c_count <= l_count
+                /* Off by 'listeners_disabled()' to avoid flip flop */
+                || c_count - l_count < (apr_uint32_t)threads_per_child +
+                                       (i_count - listeners_disabled()) *
+                                       (worker_factor / WORKER_FACTOR_SCALE)) {
+            return 0;
+        }
+    }
+    else if (busy) {
+        *busy = 1;
+    }
+    return 1;
+}
+
+static APR_INLINE int should_enable_listensocks(void)
+{
+    return !dying && listeners_disabled() && !connections_above_limit(NULL);
+}
+
+static void close_socket_nonblocking_(apr_socket_t *csd,
+                                      const char *from, int line)
+{
+    apr_status_t rv;
+    apr_os_sock_t fd = -1;
+
+    /* close_worker_sockets() may have closed it already */
+    rv = apr_os_sock_get(&fd, csd);
+    ap_log_error(APLOG_MARK, APLOG_TRACE8, 0, ap_server_conf,
+                "closing socket %i/%pp from %s:%i", (int)fd, csd, from, line);
+    if (rv == APR_SUCCESS && fd == -1) {
+        return;
+    }
+
+    apr_socket_timeout_set(csd, 0);
+    rv = apr_socket_close(csd);
+    if (rv != APR_SUCCESS) {
+        ap_log_error(APLOG_MARK, APLOG_ERR, rv, ap_server_conf, APLOGNO(00468)
+                     "error closing socket");
+        AP_DEBUG_ASSERT(0);
+    }
+}
+#define close_socket_nonblocking(csd) \
+    close_socket_nonblocking_(csd, __FUNCTION__, __LINE__)
+
+static void close_worker_sockets(void)
+{
+    int i;
+    for (i = 0; i < threads_per_child; i++) {
+        apr_socket_t *csd = worker_sockets[i];
+        if (csd) {
+            worker_sockets[i] = NULL;
+            close_socket_nonblocking(csd);
+        }
+    }
+}
+
+static void wakeup_listener(void)
+{
+    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf,
+                 "wake up listener%s", listener_may_exit ? " again" : "");
+
+    listener_may_exit = 1;
+    disable_listensocks();
+
+    /* Unblock the listener if it's poll()ing */
+    if (event_pollset && listener_is_wakeable) {
+        apr_pollset_wakeup(event_pollset);
+    }
+
+    /* unblock the listener if it's waiting for a worker */
+    if (worker_queue_info) {
+        ap_queue_info_term(worker_queue_info);
+    }
+
+    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;
+    retained->mpm->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);
+        close_worker_sockets(); /* forcefully kill all current connections */
+    }
+
+    ap_run_child_stopping(pchild, mode == ST_GRACEFUL);
+}
+
+static int event_query(int query_code, int *result, apr_status_t *rv)
+{
+    *rv = APR_SUCCESS;
+    switch (query_code) {
+    case AP_MPMQ_MAX_DAEMON_USED:
+        *result = retained->max_daemon_used;
+        break;
+    case AP_MPMQ_IS_THREADED:
+        *result = AP_MPMQ_STATIC;
+        break;
+    case AP_MPMQ_IS_FORKED:
+        *result = AP_MPMQ_DYNAMIC;
+        break;
+    case AP_MPMQ_IS_ASYNC:
+        *result = 1;
+        break;
+    case AP_MPMQ_HARD_LIMIT_DAEMONS:
+        *result = server_limit;
+        break;
+    case AP_MPMQ_HARD_LIMIT_THREADS:
+        *result = thread_limit;
+        break;
+    case AP_MPMQ_MAX_THREADS:
+        *result = threads_per_child;
+        break;
+    case AP_MPMQ_MIN_SPARE_DAEMONS:
+        *result = 0;
+        break;
+    case AP_MPMQ_MIN_SPARE_THREADS:
+        *result = min_spare_threads;
+        break;
+    case AP_MPMQ_MAX_SPARE_DAEMONS:
+        *result = 0;
+        break;
+    case AP_MPMQ_MAX_SPARE_THREADS:
+        *result = max_spare_threads;
+        break;
+    case AP_MPMQ_MAX_REQUESTS_DAEMON:
+        *result = ap_max_requests_per_child;
+        break;
+    case AP_MPMQ_MAX_DAEMONS:
+        *result = active_daemons_limit;
+        break;
+    case AP_MPMQ_MPM_STATE:
+        *result = retained->mpm->mpm_state;
+        break;
+    case AP_MPMQ_GENERATION:
+        *result = retained->mpm->my_generation;
+        break;
+    default:
+        *rv = APR_ENOTIMPL;
+        break;
+    }
+    return OK;
+}
+
+static void event_note_child_stopped(int slot, pid_t pid, ap_generation_t gen)
+{
+    if (slot != -1) { /* child had a scoreboard slot? */
+        process_score *ps = &ap_scoreboard_image->parent[slot];
+        int i;
+
+        pid = ps->pid;
+        gen = ps->generation;
+        for (i = 0; i < threads_per_child; i++) {
+            ap_update_child_status_from_indexes(slot, i, SERVER_DEAD, NULL);
+        }
+        ap_run_child_status(ap_server_conf, pid, gen, slot, MPM_CHILD_EXITED);
+        if (ps->quiescing != 2) { /* vs perform_idle_server_maintenance() */
+            retained->active_daemons--;
+        }
+        retained->total_daemons--;
+        ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf,
+                     "Child %d stopped: pid %d, gen %d, "
+                     "active %d/%d, total %d/%d/%d, quiescing %d",
+                     slot, (int)pid, (int)gen,
+                     retained->active_daemons, active_daemons_limit,
+                     retained->total_daemons, retained->max_daemon_used,
+                     server_limit, ps->quiescing);
+        ps->not_accepting = 0;
+        ps->quiescing = 0;
+        ps->pid = 0;
+    }
+    else {
+        ap_run_child_status(ap_server_conf, pid, gen, -1, MPM_CHILD_EXITED);
+    }
+}
+
+static void event_note_child_started(int slot, pid_t pid)
+{
+    ap_generation_t gen = retained->mpm->my_generation;
+
+    retained->total_daemons++;
+    retained->active_daemons++;
+    ap_scoreboard_image->parent[slot].pid = pid;
+    ap_scoreboard_image->parent[slot].generation = gen;
+    ap_run_child_status(ap_server_conf, pid, gen, slot, MPM_CHILD_STARTED);
+    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf,
+                 "Child %d started: pid %d, gen %d, "
+                 "active %d/%d, total %d/%d/%d",
+                 slot, (int)pid, (int)gen,
+                 retained->active_daemons, active_daemons_limit,
+                 retained->total_daemons, retained->max_daemon_used,
+                 server_limit);
+}
+
+static const char *event_get_name(void)
+{
+    return "event";
+}
+
+/* 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)
+{
+    retained->mpm->mpm_state = AP_MPMQ_STOPPING;
+    if (terminate_mode == ST_INIT) {
+        ap_run_child_stopping(pchild, 0);
+    }
+
+    if (pchild) {
+        apr_pool_destroy(pchild);
+    }
+
+    if (one_process) {
+        event_note_child_stopped(/* slot */ 0, 0, 0);
+    }
+
+    exit(code);
+}
+
+static void just_die(int sig)
+{
+    clean_child_exit(0);
+}
+
+/*****************************************************************
+ * Connection structures and accounting...
+ */
+
+static int child_fatal;
+
+static apr_status_t decrement_connection_count(void *cs_)
+{
+    int is_last_connection;
+    event_conn_state_t *cs = cs_;
+    ap_log_cerror(APLOG_MARK, APLOG_TRACE8, 0, cs->c,
+                  "cleanup connection from state %i", (int)cs->pub.state);
+    switch (cs->pub.state) {
+        case CONN_STATE_LINGER:
+        case CONN_STATE_LINGER_NORMAL:
+        case CONN_STATE_LINGER_SHORT:
+            apr_atomic_dec32(&lingering_count);
+            break;
+        case CONN_STATE_SUSPENDED:
+            apr_atomic_dec32(&suspended_count);
+            break;
+        default:
+            break;
+    }
+    /* Unblock the listener if it's waiting for connection_count = 0,
+     * or if the listening sockets were disabled due to limits and can
+     * now accept new connections.
+     */
+    is_last_connection = !apr_atomic_dec32(&connection_count);
+    if (listener_is_wakeable
+            && ((is_last_connection && listener_may_exit)
+                || should_enable_listensocks())) {
+        apr_pollset_wakeup(event_pollset);
+    }
+    if (dying) {
+        /* Help worker_thread_should_exit_early() */
+        ap_queue_interrupt_one(worker_queue);
+    }
+    return APR_SUCCESS;
+}
+
+static void notify_suspend(event_conn_state_t *cs)
+{
+    ap_run_suspend_connection(cs->c, cs->r);
+    cs->c->sbh = NULL;
+    cs->suspended = 1;
+}
+
+static void notify_resume(event_conn_state_t *cs, int cleanup)
+{
+    cs->suspended = 0;
+    cs->c->sbh = cleanup ? NULL : cs->sbh;
+    ap_run_resume_connection(cs->c, cs->r);
+}
+
+/*
+ * Defer flush and close of the connection by adding it to defer_linger_chain,
+ * for a worker to grab it and do the job (should that be blocking).
+ * Pre-condition: nonblocking, can be called from anywhere provided cs is not
+ *                in any timeout queue or in the pollset.
+ */
+static int defer_lingering_close(event_conn_state_t *cs)
+{
+    ap_log_cerror(APLOG_MARK, APLOG_TRACE6, 0, cs->c,
+                  "deferring close from state %i", (int)cs->pub.state);
+
+    /* The connection is not shutdown() yet strictly speaking, but it's not
+     * in any queue nor handled by a worker either (will be very soon), so
+     * to account for it somewhere we bump lingering_count now (and set
+     * deferred_linger for process_lingering_close() to know).
+     */
+    cs->pub.state = CONN_STATE_LINGER;
+    apr_atomic_inc32(&lingering_count);
+    cs->deferred_linger = 1;
+    for (;;) {
+        event_conn_state_t *chain = cs->chain = defer_linger_chain;
+        if (apr_atomic_casptr((void *)&defer_linger_chain, cs,
+                              chain) != chain) {
+            /* Race lost, try again */
+            continue;
+        }
+        return 1;
+    }
+}
+
+/* Close the connection and release its resources (ptrans), either because an
+ * unrecoverable error occured (queues or pollset add/remove) or more usually
+ * if lingering close timed out.
+ * Pre-condition: nonblocking, can be called from anywhere provided cs is not
+ *                in any timeout queue or in the pollset.
+ */
+static void close_connection(event_conn_state_t *cs)
+{
+    ap_log_cerror(APLOG_MARK, APLOG_TRACE6, 0, cs->c,
+                  "closing connection from state %i", (int)cs->pub.state);
+
+    close_socket_nonblocking(cs->pfd.desc.s);
+    ap_queue_info_push_pool(worker_queue_info, cs->p);
+}
+
+/* Shutdown the connection in case of timeout, error or resources shortage.
+ * This starts short lingering close if not already there, or directly closes
+ * the connection otherwise.
+ * Pre-condition: nonblocking, can be called from anywhere provided cs is not
+ *                in any timeout queue or in the pollset.
+ */
+static int shutdown_connection(event_conn_state_t *cs)
+{
+    if (cs->pub.state < CONN_STATE_LINGER) {
+        apr_table_setn(cs->c->notes, "short-lingering-close", "1");
+        defer_lingering_close(cs);
+    }
+    else {
+        close_connection(cs);
+    }
+    return 1;
+}
+
+/*
+ * This runs before any non-MPM cleanup code on the connection;
+ * if the connection is currently suspended as far as modules
+ * know, provide notification of resumption.
+ */
+static apr_status_t ptrans_pre_cleanup(void *dummy)
+{
+    event_conn_state_t *cs = dummy;
+
+    if (cs->suspended) {
+        notify_resume(cs, 1);
+    }
+    return APR_SUCCESS;
+}
+
+/*
+ * event_pre_read_request() and event_request_cleanup() track the
+ * current r for a given connection.
+ */
+static apr_status_t event_request_cleanup(void *dummy)
+{
+    conn_rec *c = dummy;
+    event_conn_state_t *cs = ap_get_module_config(c->conn_config,
+                                                  &mpm_event_module);
+
+    cs->r = NULL;
+    return APR_SUCCESS;
+}
+
+static void event_pre_read_request(request_rec *r, conn_rec *c)
+{
+    event_conn_state_t *cs = ap_get_module_config(c->conn_config,
+                                                  &mpm_event_module);
+
+    cs->r = r;
+    cs->sc = ap_get_module_config(ap_server_conf->module_config,
+                                  &mpm_event_module);
+    apr_pool_cleanup_register(r->pool, c, event_request_cleanup,
+                              apr_pool_cleanup_null);
+}
+
+/*
+ * event_post_read_request() tracks the current server config for a
+ * given request.
+ */
+static int event_post_read_request(request_rec *r)
+{
+    conn_rec *c = r->connection;
+    event_conn_state_t *cs = ap_get_module_config(c->conn_config,
+                                                  &mpm_event_module);
+
+    /* To preserve legacy behaviour (consistent with other MPMs), use
+     * the keepalive timeout from the base server (first on this IP:port)
+     * when none is explicitly configured on this server.
+     */
+    if (r->server->keep_alive_timeout_set) {
+        cs->sc = ap_get_module_config(r->server->module_config,
+                                      &mpm_event_module);
+    }
+    else {
+        cs->sc = ap_get_module_config(c->base_server->module_config,
+                                      &mpm_event_module);
+    }
+    return OK;
+}
+
+/* Forward declare */
+static void process_lingering_close(event_conn_state_t *cs);
+
+static void update_reqevents_from_sense(event_conn_state_t *cs, int sense)
+{
+    if (sense < 0) {
+        sense = cs->pub.sense;
+    }
+    if (sense == CONN_SENSE_WANT_READ) {
+        cs->pfd.reqevents = APR_POLLIN | APR_POLLHUP;
+    }
+    else {
+        cs->pfd.reqevents = APR_POLLOUT;
+    }
+    /* POLLERR is usually returned event only, but some pollset
+     * backends may require it in reqevents to do the right thing,
+     * so it shouldn't hurt (ignored otherwise).
+     */
+    cs->pfd.reqevents |= APR_POLLERR;
+
+    /* Reset to default for the next round */
+    cs->pub.sense = CONN_SENSE_DEFAULT;
+}
+
+/*
+ * process one connection in the worker
+ */
+static void process_socket(apr_thread_t *thd, apr_pool_t * p, apr_socket_t * sock,
+                          event_conn_state_t * cs, int my_child_num,
+                          int my_thread_num)
+{
+    conn_rec *c;
+    long conn_id = ID_FROM_CHILD_THREAD(my_child_num, my_thread_num);
+    int clogging = 0;
+    apr_status_t rv;
+    int rc = OK;
+
+    if (cs == NULL) {           /* This is a new connection */
+        listener_poll_type *pt = apr_pcalloc(p, sizeof(*pt));
+        cs = apr_pcalloc(p, sizeof(event_conn_state_t));
+        cs->bucket_alloc = apr_bucket_alloc_create(p);
+        ap_create_sb_handle(&cs->sbh, p, my_child_num, my_thread_num);
+        c = ap_run_create_connection(p, ap_server_conf, sock,
+                                     conn_id, cs->sbh, cs->bucket_alloc);
+        if (!c) {
+            ap_queue_info_push_pool(worker_queue_info, p);
+            return;
+        }
+        apr_atomic_inc32(&connection_count);
+        apr_pool_cleanup_register(c->pool, cs, decrement_connection_count,
+                                  apr_pool_cleanup_null);
+        ap_set_module_config(c->conn_config, &mpm_event_module, cs);
+        c->current_thread = thd;
+        c->cs = &cs->pub;
+        cs->c = c;
+        cs->p = p;
+        cs->sc = ap_get_module_config(ap_server_conf->module_config,
+                                      &mpm_event_module);
+        cs->pfd.desc_type = APR_POLL_SOCKET;
+        cs->pfd.desc.s = sock;
+        update_reqevents_from_sense(cs, CONN_SENSE_WANT_READ);
+        pt->type = PT_CSD;
+        pt->baton = cs;
+        cs->pfd.client_data = pt;
+        apr_pool_pre_cleanup_register(p, cs, ptrans_pre_cleanup);
+        TO_QUEUE_ELEM_INIT(cs);
+
+        ap_update_vhost_given_ip(c);
+
+        rc = ap_pre_connection(c, sock);
+        if (rc != OK && rc != DONE) {
+            ap_log_cerror(APLOG_MARK, APLOG_DEBUG, 0, c, APLOGNO(00469)
+                          "process_socket: connection aborted");
+        }
+
+        /**
+         * 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->pub.state = CONN_STATE_READ_REQUEST_LINE;
+
+        cs->pub.sense = CONN_SENSE_DEFAULT;
+        rc = OK;
+    }
+    else {
+        c = cs->c;
+        ap_update_sb_handle(cs->sbh, my_child_num, my_thread_num);
+        notify_resume(cs, 0);
+        c->current_thread = thd;
+        /* Subsequent request on a conn, and thread number is part of ID */
+        c->id = conn_id;
+    }
+
+    if (c->aborted) {
+        /* do lingering close below */
+        cs->pub.state = CONN_STATE_LINGER;
+    }
+    else if (cs->pub.state >= CONN_STATE_LINGER) {
+        /* fall through */
+    }
+    else {
+        if (cs->pub.state == CONN_STATE_READ_REQUEST_LINE
+            /* If we have an input filter which 'clogs' the input stream,
+             * like mod_ssl used to, lets just do the normal read from input
+             * filters, like the Worker MPM does. Filters that need to write
+             * where they would otherwise read, or read where they would
+             * otherwise write, should set the sense appropriately.
+             */
+             || c->clogging_input_filters) {
+read_request:
+            clogging = c->clogging_input_filters;
+            if (clogging) {
+                apr_atomic_inc32(&clogged_count);
+            }
+            rc = ap_run_process_connection(c);
+            if (clogging) {
+                apr_atomic_dec32(&clogged_count);
+            }
+            if (cs->pub.state > CONN_STATE_LINGER) {
+                cs->pub.state = CONN_STATE_LINGER;
+            }
+            if (rc == DONE) {
+                rc = OK;
+            }
+        }
+    }
+    /*
+     * The process_connection hooks above should set the connection state
+     * appropriately upon return, for event MPM to either:
+     * - do lingering close (CONN_STATE_LINGER),
+     * - wait for readability of the next request with respect to the keepalive
+     *   timeout (state CONN_STATE_CHECK_REQUEST_LINE_READABLE),
+     * - wait for read/write-ability of the underlying socket with respect to
+     *   its timeout by setting c->clogging_input_filters to 1 and the sense
+     *   to CONN_SENSE_WANT_READ/WRITE (state CONN_STATE_WRITE_COMPLETION),
+     * - keep flushing the output filters stack in nonblocking mode, and then
+     *   if required wait for read/write-ability of the underlying socket with
+     *   respect to its own timeout (state CONN_STATE_WRITE_COMPLETION); since
+     *   completion at some point may require reads (e.g. SSL_ERROR_WANT_READ),
+     *   an output filter can also set the sense to CONN_SENSE_WANT_READ at any
+     *   time for event MPM to do the right thing,
+     * - suspend the connection (SUSPENDED) such that it now interacts with
+     *   the MPM through suspend/resume_connection() hooks, and/or registered
+     *   poll callbacks (PT_USER), and/or registered timed callbacks triggered
+     *   by timer events.
+     * If a process_connection hook returns an error or no hook sets the state
+     * to one of the above expected value, we forcibly close the connection w/
+     * CONN_STATE_LINGER.  This covers the cases where no process_connection
+     * hook executes (DECLINED), or one returns OK w/o touching the state (i.e.
+     * CONN_STATE_READ_REQUEST_LINE remains after the call) which can happen
+     * with third-party modules not updated to work specifically with event MPM
+     * while this was expected to do lingering close unconditionally with
+     * worker or prefork MPMs for instance.
+     */
+    if (rc != OK || (cs->pub.state >= CONN_STATE_NUM)
+                 || (cs->pub.state < CONN_STATE_LINGER
+                     && cs->pub.state != CONN_STATE_WRITE_COMPLETION
+                     && cs->pub.state != CONN_STATE_CHECK_REQUEST_LINE_READABLE
+                     && cs->pub.state != CONN_STATE_SUSPENDED)) {
+        ap_log_cerror(APLOG_MARK, APLOG_DEBUG, 0, c, APLOGNO(10111)
+                      "process_socket: connection processing %s: closing",
+                      rc ? apr_psprintf(c->pool, "returned error %i", rc)
+                         : apr_psprintf(c->pool, "unexpected state %i",
+                                                 (int)cs->pub.state));
+        cs->pub.state = CONN_STATE_LINGER;
+    }
+
+    if (cs->pub.state == CONN_STATE_WRITE_COMPLETION) {
+        ap_filter_t *output_filter = c->output_filters;
+        apr_status_t rv;
+        ap_update_child_status(cs->sbh, SERVER_BUSY_WRITE, NULL);
+        while (output_filter->next != NULL) {
+            output_filter = output_filter->next;
+        }
+        rv = output_filter->frec->filter_func.out_func(output_filter, NULL);
+        if (rv != APR_SUCCESS) {
+            ap_log_cerror(APLOG_MARK, APLOG_DEBUG, rv, c, APLOGNO(00470)
+                          "network write failure in core output filter");
+            cs->pub.state = CONN_STATE_LINGER;
+        }
+        else if (c->data_in_output_filters ||
+                 cs->pub.sense == CONN_SENSE_WANT_READ) {
+            /* Still in WRITE_COMPLETION_STATE:
+             * Set a read/write timeout for this connection, and let the
+             * event thread poll for read/writeability.
+             */
+            cs->queue_timestamp = apr_time_now();
+            notify_suspend(cs);
+
+            update_reqevents_from_sense(cs, -1);
+            apr_thread_mutex_lock(timeout_mutex);
+            TO_QUEUE_APPEND(cs->sc->wc_q, cs);
+            rv = apr_pollset_add(event_pollset, &cs->pfd);
+            if (rv != APR_SUCCESS && !APR_STATUS_IS_EEXIST(rv)) {
+                AP_DEBUG_ASSERT(0);
+                TO_QUEUE_REMOVE(cs->sc->wc_q, cs);
+                apr_thread_mutex_unlock(timeout_mutex);
+                ap_log_error(APLOG_MARK, APLOG_ERR, rv, ap_server_conf, APLOGNO(03465)
+                             "process_socket: apr_pollset_add failure for "
+                             "write completion");
+                close_connection(cs);
+                signal_threads(ST_GRACEFUL);
+            }
+            else {
+                apr_thread_mutex_unlock(timeout_mutex);
+            }
+            return;
+        }
+        else if (c->keepalive != AP_CONN_KEEPALIVE || c->aborted) {
+            cs->pub.state = CONN_STATE_LINGER;
+        }
+        else if (c->data_in_input_filters) {
+            cs->pub.state = CONN_STATE_READ_REQUEST_LINE;
+            goto read_request;
+        }
+        else if (!listener_may_exit) {
+            cs->pub.state = CONN_STATE_CHECK_REQUEST_LINE_READABLE;
+        }
+        else {
+            cs->pub.state = CONN_STATE_LINGER;
+        }
+    }
+
+    if (cs->pub.state == CONN_STATE_CHECK_REQUEST_LINE_READABLE) {
+        ap_update_child_status(cs->sbh, SERVER_BUSY_KEEPALIVE, NULL);
+
+        /* It greatly simplifies the logic to use a single timeout value per q
+         * 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->queue_timestamp = apr_time_now();
+        notify_suspend(cs);
+
+        /* Add work to pollset. */
+        update_reqevents_from_sense(cs, CONN_SENSE_WANT_READ);
+        apr_thread_mutex_lock(timeout_mutex);
+        TO_QUEUE_APPEND(cs->sc->ka_q, cs);
+        rv = apr_pollset_add(event_pollset, &cs->pfd);
+        if (rv != APR_SUCCESS && !APR_STATUS_IS_EEXIST(rv)) {
+            AP_DEBUG_ASSERT(0);
+            TO_QUEUE_REMOVE(cs->sc->ka_q, cs);
+            apr_thread_mutex_unlock(timeout_mutex);
+            ap_log_error(APLOG_MARK, APLOG_ERR, rv, ap_server_conf, APLOGNO(03093)
+                         "process_socket: apr_pollset_add failure for "
+                         "keep alive");
+            close_connection(cs);
+            signal_threads(ST_GRACEFUL);
+        }
+        else {
+            apr_thread_mutex_unlock(timeout_mutex);
+        }
+        return;
+    }
+
+    if (cs->pub.state == CONN_STATE_SUSPENDED) {
+        apr_atomic_inc32(&suspended_count);
+        notify_suspend(cs);
+        return;
+    }
+
+    /* CONN_STATE_LINGER[_*] fall through process_lingering_close() */
+    if (cs->pub.state >= CONN_STATE_LINGER) {
+        process_lingering_close(cs);
+        return;
+    }
+}
+
+/* conns_this_child has gone to zero or below.  See if the admin coded
+   "MaxConnectionsPerChild 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) {
+        ap_log_error(APLOG_MARK, APLOG_TRACE1, 0, ap_server_conf,
+                     "Stopping process due to MaxConnectionsPerChild");
+        signal_threads(ST_GRACEFUL);
+    }
+    else {
+        /* keep going */
+        conns_this_child = APR_INT32_MAX;
+    }
+}
+
+static int close_listeners(int *closed)
+{
+    ap_log_error(APLOG_MARK, APLOG_TRACE6, 0, ap_server_conf,
+                 "clos%s listeners (connection_count=%u)",
+                 *closed ? "ed" : "ing", apr_atomic_read32(&connection_count));
+    if (!*closed) {
+        int i;
+
+        ap_close_listeners_ex(my_bucket->listeners);
+        *closed = 1; /* once */
+
+        dying = 1;
+        ap_scoreboard_image->parent[ap_child_slot].quiescing = 1;
+        for (i = 0; i < threads_per_child; ++i) {
+            ap_update_child_status_from_indexes(ap_child_slot, i,
+                                                SERVER_GRACEFUL, NULL);
+        }
+        /* wake up the main thread */
+        kill(ap_my_pid, SIGTERM);
+
+        ap_queue_info_free_idle_pools(worker_queue_info);
+        ap_queue_interrupt_all(worker_queue);
+
+        return 1;
+    }
+    return 0;
+}
+
+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 push_timer2worker(timer_event_t* te)
+{
+    return ap_queue_push_timer(worker_queue, te);
+}
+
+/*
+ * Pre-condition: cs is neither in event_pollset nor a timeout queue
+ * this function may only be called by the listener
+ */
+static apr_status_t push2worker(event_conn_state_t *cs, apr_socket_t *csd,
+                                apr_pool_t *ptrans)
+{
+    apr_status_t rc;
+
+    if (cs) {
+        csd = cs->pfd.desc.s;
+        ptrans = cs->p;
+    }
+    rc = ap_queue_push_socket(worker_queue, csd, cs, ptrans);
+    if (rc != APR_SUCCESS) {
+        ap_log_error(APLOG_MARK, APLOG_CRIT, rc, ap_server_conf, APLOGNO(00471)
+                     "push2worker: ap_queue_push_socket failed");
+        /* trash the connection; we couldn't queue the connected
+         * socket to a worker
+         */
+        if (cs) {
+            shutdown_connection(cs);
+        }
+        else {
+            if (csd) {
+                close_socket_nonblocking(csd);
+            }
+            if (ptrans) {
+                ap_queue_info_push_pool(worker_queue_info, ptrans);
+            }
+        }
+        signal_threads(ST_GRACEFUL);
+    }
+
+    return rc;
+}
+
+/* get_worker:
+ *     If *have_idle_worker_p == 0, reserve a worker thread, and set
+ *     *have_idle_worker_p = 1.
+ *     If *have_idle_worker_p is already 1, will do nothing.
+ *     If blocking == 1, block if all workers are currently busy.
+ *     If no worker was available immediately, will set *all_busy to 1.
+ *     XXX: If there are no workers, we should not block immediately but
+ *     XXX: close all keep-alive connections first.
+ */
+static void get_worker(int *have_idle_worker_p, int blocking, int *all_busy)
+{
+    apr_status_t rc;
+
+    if (*have_idle_worker_p) {
+        /* already reserved a worker thread - must have hit a
+         * transient error on a previous pass
+         */
+        return;
+    }
+
+    if (blocking)
+        rc = ap_queue_info_wait_for_idler(worker_queue_info, all_busy);
+    else
+        rc = ap_queue_info_try_get_idler(worker_queue_info);
+
+    if (rc == APR_SUCCESS || APR_STATUS_IS_EOF(rc)) {
+        *have_idle_worker_p = 1;
+    }
+    else if (!blocking && rc == APR_EAGAIN) {
+        *all_busy = 1;
+    }
+    else {
+        ap_log_error(APLOG_MARK, APLOG_ERR, rc, ap_server_conf, APLOGNO(00472)
+                     "ap_queue_info_wait_for_idler failed.  "
+                     "Attempting to shutdown process gracefully");
+        signal_threads(ST_GRACEFUL);
+    }
+}
+
+/* Structures to reuse */
+static timer_event_t timer_free_ring;
+
+static apr_skiplist *timer_skiplist;
+static volatile apr_time_t timers_next_expiry;
+
+/* Same goal as for TIMEOUT_FUDGE_FACTOR (avoid extra poll calls), but applied
+ * to timers. Since their timeouts are custom (user defined), we can't be too
+ * approximative here (hence using 0.01s).
+ */
+#define EVENT_FUDGE_FACTOR apr_time_from_msec(10)
+
+/* The following compare function is used by apr_skiplist_insert() to keep the
+ * elements (timers) sorted and provide O(log n) complexity (this is also true
+ * for apr_skiplist_{find,remove}(), but those are not used in MPM event where
+ * inserted timers are not searched nor removed, but with apr_skiplist_pop()
+ * which does use any compare function).  It is meant to return 0 when a == b,
+ * <0 when a < b, and >0 when a > b.  However apr_skiplist_insert() will not
+ * add duplicates (i.e. a == b), and apr_skiplist_add() is only available in
+ * APR 1.6, yet multiple timers could possibly be created in the same micro-
+ * second (duplicates with regard to apr_time_t); therefore we implement the
+ * compare function to return +1 instead of 0 when compared timers are equal,
+ * thus duplicates are still added after each other (in order of insertion).
+ */
+static int timer_comp(void *a, void *b)
+{
+    apr_time_t t1 = (apr_time_t) ((timer_event_t *)a)->when;
+    apr_time_t t2 = (apr_time_t) ((timer_event_t *)b)->when;
+    AP_DEBUG_ASSERT(t1);
+    AP_DEBUG_ASSERT(t2);
+    return ((t1 < t2) ? -1 : 1);
+}
+
+static apr_thread_mutex_t *g_timer_skiplist_mtx;
+
+static apr_status_t event_register_timed_callback(apr_time_t t,
+                                                  ap_mpm_callback_fn_t *cbfn,
+                                                  void *baton)
+{
+    timer_event_t *te;
+    /* oh yeah, and make locking smarter/fine grained. */
+    apr_thread_mutex_lock(g_timer_skiplist_mtx);
+
+    if (!APR_RING_EMPTY(&timer_free_ring.link, timer_event_t, link)) {
+        te = APR_RING_FIRST(&timer_free_ring.link);
+        APR_RING_REMOVE(te, link);
+    }
+    else {
+        te = apr_skiplist_alloc(timer_skiplist, sizeof(timer_event_t));
+        APR_RING_ELEM_INIT(te, link);
+    }
+
+    te->cbfunc = cbfn;
+    te->baton = baton;
+    /* XXXXX: optimize */
+    te->when = t + apr_time_now();
+
+    { 
+        apr_time_t next_expiry;
+
+        /* Okay, add sorted by when.. */
+        apr_skiplist_insert(timer_skiplist, te);
+
+        /* Cheaply update the global timers_next_expiry with this event's
+         * if it expires before.
+         */
+        next_expiry = timers_next_expiry;
+        if (!next_expiry || next_expiry > te->when + EVENT_FUDGE_FACTOR) {
+            timers_next_expiry = te->when;
+            /* Unblock the poll()ing listener for it to update its timeout. */
+            if (listener_is_wakeable) {
+                apr_pollset_wakeup(event_pollset);
+            }
+        }
+    }
+
+    apr_thread_mutex_unlock(g_timer_skiplist_mtx);
+
+    return APR_SUCCESS;
+}
+
+
+/*
+ * Flush data and close our side of the connection, then drain incoming data.
+ * If the latter would block put the connection in one of the linger timeout
+ * queues to be called back when ready, and repeat until it's closed by peer.
+ * Only to be called in the worker thread, and since it's in immediate call
+ * stack, we can afford a comfortable buffer size to consume data quickly.
+ * Pre-condition: cs is not in any timeout queue and not in the pollset,
+ *                timeout_mutex is not locked
+ */
+#define LINGERING_BUF_SIZE (32 * 1024)
+static void process_lingering_close(event_conn_state_t *cs)
+{
+    apr_socket_t *csd = ap_get_conn_socket(cs->c);
+    char dummybuf[LINGERING_BUF_SIZE];
+    apr_size_t nbytes;
+    apr_status_t rv;
+    struct timeout_queue *q;
+
+    ap_log_cerror(APLOG_MARK, APLOG_TRACE6, 0, cs->c,
+                  "lingering close from state %i", (int)cs->pub.state);
+    AP_DEBUG_ASSERT(cs->pub.state >= CONN_STATE_LINGER);
+
+    if (cs->pub.state == CONN_STATE_LINGER) {
+        /* defer_lingering_close() may have bumped lingering_count already */
+        if (!cs->deferred_linger) {
+            apr_atomic_inc32(&lingering_count);
+        }
+
+        apr_socket_timeout_set(csd, apr_time_from_sec(SECONDS_TO_LINGER));
+        if (ap_start_lingering_close(cs->c)) {
+            notify_suspend(cs);
+            close_connection(cs);
+            return;
+        }
+
+        cs->queue_timestamp = apr_time_now();
+        /* Clear APR_INCOMPLETE_READ if it was ever set, we'll do the poll()
+         * at the listener only from now, if needed.
+         */
+        apr_socket_opt_set(csd, APR_INCOMPLETE_READ, 0);
+        /*
+         * If some module requested a shortened waiting period, only wait for
+         * 2s (SECONDS_TO_LINGER). This is useful for mitigating certain
+         * DoS attacks.
+         */
+        if (apr_table_get(cs->c->notes, "short-lingering-close")) {
+            cs->pub.state = CONN_STATE_LINGER_SHORT;
+        }
+        else {
+            cs->pub.state = CONN_STATE_LINGER_NORMAL;
+        }
+        notify_suspend(cs);
+    }
+
+    apr_socket_timeout_set(csd, 0);
+    do {
+        nbytes = sizeof(dummybuf);
+        rv = apr_socket_recv(csd, dummybuf, &nbytes);
+    } while (rv == APR_SUCCESS);
+
+    if (!APR_STATUS_IS_EAGAIN(rv)) {
+        close_connection(cs);
+        return;
+    }
+
+    /* (Re)queue the connection to come back when readable */
+    update_reqevents_from_sense(cs, CONN_SENSE_WANT_READ);
+    q = (cs->pub.state == CONN_STATE_LINGER_SHORT) ? short_linger_q : linger_q;
+    apr_thread_mutex_lock(timeout_mutex);
+    TO_QUEUE_APPEND(q, cs);
+    rv = apr_pollset_add(event_pollset, &cs->pfd);
+    if (rv != APR_SUCCESS && !APR_STATUS_IS_EEXIST(rv)) {
+        AP_DEBUG_ASSERT(0);
+        TO_QUEUE_REMOVE(q, cs);
+        apr_thread_mutex_unlock(timeout_mutex);
+        ap_log_error(APLOG_MARK, APLOG_ERR, rv, ap_server_conf, APLOGNO(03092)
+                     "process_lingering_close: apr_pollset_add failure");
+        close_connection(cs);
+        signal_threads(ST_GRACEFUL);
+        return;
+    }
+    apr_thread_mutex_unlock(timeout_mutex);
+}
+
+/* call 'func' for all elements of 'q' above 'expiry'.
+ * Pre-condition: timeout_mutex must already be locked
+ * Post-condition: timeout_mutex will be locked again
+ */
+static void process_timeout_queue(struct timeout_queue *q, apr_time_t expiry,
+                                  int (*func)(event_conn_state_t *))
+{
+    apr_uint32_t total = 0, count;
+    event_conn_state_t *first, *cs, *last;
+    struct event_conn_state_t trash;
+    struct timeout_queue *qp;
+    apr_status_t rv;
+
+    if (!*q->total) {
+        return;
+    }
+
+    APR_RING_INIT(&trash.timeout_list, event_conn_state_t, timeout_list);
+    for (qp = q; qp; qp = qp->next) {
+        count = 0;
+        cs = first = last = APR_RING_FIRST(&qp->head);
+        while (cs != APR_RING_SENTINEL(&qp->head, event_conn_state_t,
+                                       timeout_list)) {
+            /* Trash the entry if:
+             * - no expiry was given (zero means all), or
+             * - it expired (according to the queue timeout), or
+             * - the system clock skewed in the past: no entry should be
+             *   registered above the given expiry (~now) + the queue
+             *   timeout, we won't keep any here (eg. for centuries).
+             *
+             * Otherwise stop, no following entry will match thanks to the
+             * single timeout per queue (entries are added to the end!).
+             * This allows maintenance in O(1).
+             */
+            if (expiry && cs->queue_timestamp + qp->timeout > expiry
+                       && cs->queue_timestamp < expiry + qp->timeout) {
+                /* Since this is the next expiring entry of this queue, update
+                 * the global queues_next_expiry if it's later than this one.
+                 */
+                apr_time_t elem_expiry = cs->queue_timestamp + qp->timeout;
+                apr_time_t next_expiry = queues_next_expiry;
+                if (!next_expiry
+                        || next_expiry > elem_expiry + TIMEOUT_FUDGE_FACTOR) {
+                    queues_next_expiry = elem_expiry;
+                }
+                break;
+            }
+
+            last = cs;
+            rv = apr_pollset_remove(event_pollset, &cs->pfd);
+            if (rv != APR_SUCCESS && !APR_STATUS_IS_NOTFOUND(rv)) {
+                AP_DEBUG_ASSERT(0);
+                ap_log_cerror(APLOG_MARK, APLOG_ERR, rv, cs->c, APLOGNO(00473)
+                              "apr_pollset_remove failed");
+            }
+            cs = APR_RING_NEXT(cs, timeout_list);
+            count++;
+        }
+        if (!count)
+            continue;
+
+        APR_RING_UNSPLICE(first, last, timeout_list);
+        APR_RING_SPLICE_TAIL(&trash.timeout_list, first, last, event_conn_state_t,
+                             timeout_list);
+        AP_DEBUG_ASSERT(*q->total >= count && qp->count >= count);
+        *q->total -= count;
+        qp->count -= count;
+        total += count;
+    }
+    if (!total)
+        return;
+
+    apr_thread_mutex_unlock(timeout_mutex);
+    first = APR_RING_FIRST(&trash.timeout_list);
+    do {
+        cs = APR_RING_NEXT(first, timeout_list);
+        TO_QUEUE_ELEM_INIT(first);
+        func(first);
+        first = cs;
+    } while (--total);
+    apr_thread_mutex_lock(timeout_mutex);
+}
+
+static void process_keepalive_queue(apr_time_t expiry)
+{
+    /* If all workers are busy, we kill older keep-alive connections so
+     * that they may connect to another process.
+     */
+    if (!expiry && *keepalive_q->total) {
+        ap_log_error(APLOG_MARK, APLOG_TRACE1, 0, ap_server_conf,
+                     "All workers are busy or dying, will shutdown %u "
+                     "keep-alive connections", *keepalive_q->total);
+    }
+    process_timeout_queue(keepalive_q, expiry, shutdown_connection);
+}
+
+static void * APR_THREAD_FUNC listener_thread(apr_thread_t * thd, void *dummy)
+{
+    apr_status_t rc;
+    proc_info *ti = dummy;
+    int process_slot = ti->pslot;
+    struct process_score *ps = ap_get_scoreboard_process(process_slot);
+    int closed = 0;
+    int have_idle_worker = 0;
+    apr_time_t last_log;
+
+    last_log = apr_time_now();
+    free(ti);
+
+    /* Unblock the signal used to wake this thread up, and set a handler for
+     * it.
+     */
+    apr_signal(LISTENER_SIGNAL, dummy_signal_handler);
+    unblock_signal(LISTENER_SIGNAL);
+
+    for (;;) {
+        timer_event_t *te;
+        const apr_pollfd_t *out_pfd;
+        apr_int32_t num = 0;
+        apr_interval_time_t timeout;
+        apr_time_t now, expiry = -1;
+        int workers_were_busy = 0;
+
+        if (conns_this_child <= 0)
+            check_infinite_requests();
+
+        if (listener_may_exit) {
+            int first_close = close_listeners(&closed);
+
+            if (terminate_mode == ST_UNGRACEFUL
+                || apr_atomic_read32(&connection_count) == 0)
+                break;
+
+            /* Don't wait in poll() for the first close (i.e. dying now), we
+             * want to maintain the queues and schedule defer_linger_chain ASAP
+             * to kill kept-alive connection and shutdown the workers and child
+             * faster.
+             */
+            if (first_close) {
+                goto do_maintenance; /* with expiry == -1 */
+            }
+        }
+
+        now = apr_time_now();
+        if (APLOGtrace6(ap_server_conf)) {
+            /* trace log status every second */
+            if (now - last_log > apr_time_from_sec(1)) {
+                last_log = now;
+                apr_thread_mutex_lock(timeout_mutex);
+                ap_log_error(APLOG_MARK, APLOG_TRACE6, 0, ap_server_conf,
+                             "connections: %u (clogged: %u write-completion: %d "
+                             "keep-alive: %d lingering: %d suspended: %u)",
+                             apr_atomic_read32(&connection_count),
+                             apr_atomic_read32(&clogged_count),
+                             apr_atomic_read32(write_completion_q->total),
+                             apr_atomic_read32(keepalive_q->total),
+                             apr_atomic_read32(&lingering_count),
+                             apr_atomic_read32(&suspended_count));
+                if (dying) {
+                    ap_log_error(APLOG_MARK, APLOG_TRACE6, 0, ap_server_conf,
+                                 "%u/%u workers shutdown",
+                                 apr_atomic_read32(&threads_shutdown),
+                                 threads_per_child);
+                }
+                apr_thread_mutex_unlock(timeout_mutex);
+            }
+        }
+
+        /* Start with an infinite poll() timeout and update it according to
+         * the next expiring timer or queue entry. If there are none, either
+         * the listener is wakeable and it can poll() indefinitely until a wake
+         * up occurs, otherwise periodic checks (maintenance, shutdown, ...)
+         * must be performed.
+         */
+        now = apr_time_now();
+        timeout = -1;
+
+        /* Push expired timers to a worker, the first remaining one determines
+         * the maximum time to poll() below, if any.
+         */
+        expiry = timers_next_expiry;
+        if (expiry && expiry < now) {
+            apr_thread_mutex_lock(g_timer_skiplist_mtx);
+            while ((te = apr_skiplist_peek(timer_skiplist))) {
+                if (te->when > now) {
+                    timers_next_expiry = te->when;
+                    timeout = te->when - now;
+                    break;
+                }
+                apr_skiplist_pop(timer_skiplist, NULL);
+                push_timer2worker(te);
+            }
+            if (!te) {
+                timers_next_expiry = 0;
+            }
+            apr_thread_mutex_unlock(g_timer_skiplist_mtx);
+        }
+
+        /* Same for queues, use their next expiry, if any. */
+        expiry = queues_next_expiry;
+        if (expiry
+                && (timeout < 0
+                    || expiry <= now
+                    || timeout > expiry - now)) {
+            timeout = expiry > now ? expiry - now : 0;
+        }
+
+        /* When non-wakeable, don't wait more than 100 ms, in any case. */
+#define NON_WAKEABLE_POLL_TIMEOUT apr_time_from_msec(100)
+        if (!listener_is_wakeable
+                && (timeout < 0
+                    || timeout > NON_WAKEABLE_POLL_TIMEOUT)) {
+            timeout = NON_WAKEABLE_POLL_TIMEOUT;
+        }
+        else if (timeout > 0) {
+            /* apr_pollset_poll() might round down the timeout to milliseconds,
+             * let's forcibly round up here to never return before the timeout.
+             */
+            timeout = apr_time_from_msec(
+                apr_time_as_msec(timeout + apr_time_from_msec(1) - 1)
+            );
+        }
+
+        ap_log_error(APLOG_MARK, APLOG_TRACE7, 0, ap_server_conf,
+                     "polling with timeout=%" APR_TIME_T_FMT
+                     " queues_timeout=%" APR_TIME_T_FMT
+                     " timers_timeout=%" APR_TIME_T_FMT,
+                     timeout, queues_next_expiry - now,
+                     timers_next_expiry - now);
+
+        rc = apr_pollset_poll(event_pollset, timeout, &num, &out_pfd);
+        if (rc != APR_SUCCESS) {
+            if (!APR_STATUS_IS_EINTR(rc) && !APR_STATUS_IS_TIMEUP(rc)) {
+                ap_log_error(APLOG_MARK, APLOG_CRIT, rc, ap_server_conf,
+                             "apr_pollset_poll failed.  Attempting to "
+                             "shutdown process gracefully");
+                signal_threads(ST_GRACEFUL);
+            }
+            num = 0;
+        }
+
+        if (APLOGtrace7(ap_server_conf)) {
+            now = apr_time_now();
+            ap_log_error(APLOG_MARK, APLOG_TRACE7, rc, ap_server_conf,
+                         "polled with num=%u exit=%d/%d conns=%d"
+                         " queues_timeout=%" APR_TIME_T_FMT
+                         " timers_timeout=%" APR_TIME_T_FMT,
+                         num, listener_may_exit, dying,
+                         apr_atomic_read32(&connection_count),
+                         queues_next_expiry - now, timers_next_expiry - now);
+        }
+
+        /* XXX possible optimization: stash the current time for use as
+         * r->request_time for new requests or queues maintenance
+         */
+
+        for (; num; --num, ++out_pfd) {
+            listener_poll_type *pt = (listener_poll_type *) out_pfd->client_data;
+            if (pt->type == PT_CSD) {
+                /* one of the sockets is readable */
+                event_conn_state_t *cs = (event_conn_state_t *) pt->baton;
+                struct timeout_queue *remove_from_q = NULL;
+                /* don't wait for a worker for a keepalive request or
+                 * lingering close processing. */
+                int blocking = 0;
+
+                switch (cs->pub.state) {
+                case CONN_STATE_WRITE_COMPLETION:
+                    remove_from_q = cs->sc->wc_q;
+                    blocking = 1;
+                    break;
+
+                case CONN_STATE_CHECK_REQUEST_LINE_READABLE:
+                    cs->pub.state = CONN_STATE_READ_REQUEST_LINE;
+                    remove_from_q = cs->sc->ka_q;
+                    break;
+
+                case CONN_STATE_LINGER_NORMAL:
+                    remove_from_q = linger_q;
+                    break;
+
+                case CONN_STATE_LINGER_SHORT:
+                    remove_from_q = short_linger_q;
+                    break;
+
+                default:
+                    ap_log_error(APLOG_MARK, APLOG_CRIT, rc,
+                                 ap_server_conf, APLOGNO(03096)
+                                 "event_loop: unexpected state %d",
+                                 cs->pub.state);
+                    ap_assert(0);
+                }
+
+                if (remove_from_q) {
+                    apr_thread_mutex_lock(timeout_mutex);
+                    TO_QUEUE_REMOVE(remove_from_q, cs);
+                    rc = apr_pollset_remove(event_pollset, &cs->pfd);
+                    apr_thread_mutex_unlock(timeout_mutex);
+                    /*
+                     * 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 && !APR_STATUS_IS_NOTFOUND(rc)) {
+                        AP_DEBUG_ASSERT(0);
+                        ap_log_error(APLOG_MARK, APLOG_ERR, rc, ap_server_conf,
+                                     APLOGNO(03094) "pollset remove failed");
+                        close_connection(cs);
+                        signal_threads(ST_GRACEFUL);
+                        break;
+                    }
+
+                    /* If we don't get a worker immediately (nonblocking), we
+                     * close the connection; the client can re-connect to a
+                     * different process for keepalive, and for lingering close
+                     * the connection will be shutdown so the choice is to favor
+                     * incoming/alive connections.
+                     */
+                    get_worker(&have_idle_worker, blocking,
+                               &workers_were_busy);
+                    if (!have_idle_worker) {
+                        shutdown_connection(cs);
+                    }
+                    else if (push2worker(cs, NULL, NULL) == APR_SUCCESS) {
+                        have_idle_worker = 0;
+                    }
+                }
+            }
+            else if (pt->type == PT_ACCEPT && !listeners_disabled()) {
+                /* A Listener Socket is ready for an accept() */
+                if (workers_were_busy) {
+                    disable_listensocks();
+                    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf,
+                                 "All workers busy, not accepting new conns "
+                                 "in this process");
+                }
+                else if (connections_above_limit(&workers_were_busy)) {
+                    disable_listensocks();
+                    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf,
+                                 "Too many open connections (%u), "
+                                 "not accepting new conns in this process",
+                                 apr_atomic_read32(&connection_count));
+                    ap_log_error(APLOG_MARK, APLOG_TRACE1, 0, ap_server_conf,
+                                 "Idle workers: %u",
+                                 ap_queue_info_num_idlers(worker_queue_info));
+                }
+                else if (!listener_may_exit) {
+                    void *csd = NULL;
+                    ap_listen_rec *lr = (ap_listen_rec *) pt->baton;
+                    apr_pool_t *ptrans;         /* Pool for per-transaction stuff */
+                    ap_queue_info_pop_pool(worker_queue_info, &ptrans);
+
+                    if (ptrans == NULL) {
+                        /* create a new transaction pool for each accepted socket */
+                        apr_allocator_t *allocator = NULL;
+
+                        rc = apr_allocator_create(&allocator);
+                        if (rc == APR_SUCCESS) {
+                            apr_allocator_max_free_set(allocator,
+                                                       ap_max_mem_free);
+                            rc = apr_pool_create_ex(&ptrans, pconf, NULL,
+                                                    allocator);
+                            if (rc == APR_SUCCESS) {
+                                apr_pool_tag(ptrans, "transaction");
+                                apr_allocator_owner_set(allocator, ptrans);
+                            }
+                        }
+                        if (rc != APR_SUCCESS) {
+                            ap_log_error(APLOG_MARK, APLOG_CRIT, rc,
+                                         ap_server_conf, APLOGNO(03097)
+                                         "Failed to create transaction pool");
+                            if (allocator) {
+                                apr_allocator_destroy(allocator);
+                            }
+                            resource_shortage = 1;
+                            signal_threads(ST_GRACEFUL);
+                            continue;
+                        }
+                    }
+
+                    get_worker(&have_idle_worker, 1, &workers_were_busy);
+                    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) {
+                        conns_this_child--;
+                        if (push2worker(NULL, csd, ptrans) == APR_SUCCESS) {
+                            have_idle_worker = 0;
+                        }
+                    }
+                    else {
+                        ap_queue_info_push_pool(worker_queue_info, ptrans);
+                    }
+                }
+            }               /* if:else on pt->type */
+        } /* for processing poll */
+
+        /* We process the timeout queues here only when the global
+         * queues_next_expiry is passed. This happens accurately since
+         * adding to the queues (in workers) can only decrease this expiry,
+         * while latest ones are only taken into account here (in listener)
+         * during queues' processing, with the lock held. This works both
+         * with and without wake-ability.
+         */
+        expiry = queues_next_expiry;
+do_maintenance:
+        if (expiry && expiry < (now = apr_time_now())) {
+            ap_log_error(APLOG_MARK, APLOG_TRACE7, 0, ap_server_conf,
+                         "queues maintenance with timeout=%" APR_TIME_T_FMT,
+                         expiry > 0 ? expiry - now : -1);
+            apr_thread_mutex_lock(timeout_mutex);
+
+            /* Steps below will recompute this. */
+            queues_next_expiry = 0;
+
+            /* Step 1: keepalive timeouts */
+            if (workers_were_busy || dying) {
+                process_keepalive_queue(0); /* kill'em all \m/ */
+            }
+            else {
+                process_keepalive_queue(now);
+            }
+            /* Step 2: write completion timeouts */
+            process_timeout_queue(write_completion_q, now,
+                                  defer_lingering_close);
+            /* Step 3: (normal) lingering close completion timeouts */
+            if (dying && linger_q->timeout > short_linger_q->timeout) {
+                /* Dying, force short timeout for normal lingering close */
+                linger_q->timeout = short_linger_q->timeout;
+            }
+            process_timeout_queue(linger_q, now, shutdown_connection);
+            /* Step 4: (short) lingering close completion timeouts */
+            process_timeout_queue(short_linger_q, now, shutdown_connection);
+
+            apr_thread_mutex_unlock(timeout_mutex);
+            ap_log_error(APLOG_MARK, APLOG_TRACE7, 0, ap_server_conf,
+                         "queues maintained with timeout=%" APR_TIME_T_FMT,
+                         queues_next_expiry > now ? queues_next_expiry - now
+                                                  : -1);
+
+            ps->keep_alive = apr_atomic_read32(keepalive_q->total);
+            ps->write_completion = apr_atomic_read32(write_completion_q->total);
+            ps->connections = apr_atomic_read32(&connection_count);
+            ps->suspended = apr_atomic_read32(&suspended_count);
+            ps->lingering_close = apr_atomic_read32(&lingering_count);
+        }
+        else if ((workers_were_busy || dying)
+                 && apr_atomic_read32(keepalive_q->total)) {
+            apr_thread_mutex_lock(timeout_mutex);
+            process_keepalive_queue(0); /* kill'em all \m/ */
+            apr_thread_mutex_unlock(timeout_mutex);
+            ps->keep_alive = 0;
+        }
+
+        /* If there are some lingering closes to defer (to a worker), schedule
+         * them now. We might wakeup a worker spuriously if another one empties
+         * defer_linger_chain in the meantime, but there also may be no active
+         * or all busy workers for an undefined time.  In any case a deferred
+         * lingering close can't starve if we do that here since the chain is
+         * filled only above in the listener and it's emptied only in the
+         * worker(s); thus a NULL here means it will stay so while the listener
+         * waits (possibly indefinitely) in poll().
+         */
+        if (defer_linger_chain) {
+            get_worker(&have_idle_worker, 0, &workers_were_busy);
+            if (have_idle_worker
+                    && defer_linger_chain /* re-test */
+                    && push2worker(NULL, NULL, NULL) == APR_SUCCESS) {
+                have_idle_worker = 0;
+            }
+        }
+
+        if (!workers_were_busy && should_enable_listensocks()) {
+            enable_listensocks();
+        }
+    } /* listener main loop */
+
+    ap_queue_term(worker_queue);
+
+    apr_thread_exit(thd, APR_SUCCESS);
+    return NULL;
+}
+
+/*
+ * During graceful shutdown, if there are more running worker threads than
+ * open connections, exit one worker thread.
+ *
+ * return 1 if thread should exit, 0 if it should continue running.
+ */
+static int worker_thread_should_exit_early(void)
+{
+    for (;;) {
+        apr_uint32_t conns = apr_atomic_read32(&connection_count);
+        apr_uint32_t dead = apr_atomic_read32(&threads_shutdown);
+        apr_uint32_t newdead;
+
+        AP_DEBUG_ASSERT(dead <= threads_per_child);
+        if (conns >= threads_per_child - dead)
+            return 0;
+
+        newdead = dead + 1;
+        if (apr_atomic_cas32(&threads_shutdown, newdead, dead) == dead) {
+            /*
+             * No other thread has exited in the mean time, safe to exit
+             * this one.
+             */
+            return 1;
+        }
+    }
+}
+
+/* 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->pslot;
+    int thread_slot = ti->tslot;
+    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].tid = apr_os_thread_current();
+    ap_scoreboard_image->servers[process_slot][thread_slot].generation = retained->mpm->my_generation;
+    ap_update_child_status_from_indexes(process_slot, thread_slot,
+                                        SERVER_STARTING, NULL);
+
+    for (;;) {
+        apr_socket_t *csd = NULL;
+        event_conn_state_t *cs;
+        timer_event_t *te = NULL;
+        apr_pool_t *ptrans;         /* Pool for per-transaction stuff */
+
+        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;
+            }
+            /* A new idler may have changed connections_above_limit(),
+             * let the listener know and decide.
+             */
+            if (listener_is_wakeable && should_enable_listensocks()) {
+                apr_pollset_wakeup(event_pollset);
+            }
+            is_idle = 1;
+        }
+
+        ap_update_child_status_from_indexes(process_slot, thread_slot,
+                                            dying ? SERVER_GRACEFUL
+                                                  : SERVER_READY, NULL);
+      worker_pop:
+        if (workers_may_exit) {
+            break;
+        }
+        if (dying && worker_thread_should_exit_early()) {
+            break;
+        }
+
+        rv = ap_queue_pop_something(worker_queue, &csd, (void **)&cs,
+                                    &ptrans, &te);
+
+        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,
+                             APLOGNO(03099) "ap_queue_pop_socket failed");
+            }
+            continue;
+        }
+        if (te != NULL) {
+            te->cbfunc(te->baton);
+
+            {
+                apr_thread_mutex_lock(g_timer_skiplist_mtx);
+                APR_RING_INSERT_TAIL(&timer_free_ring.link, te, timer_event_t, link);
+                apr_thread_mutex_unlock(g_timer_skiplist_mtx);
+            }
+        }
+        else {
+            is_idle = 0;
+            if (csd != NULL) {
+                worker_sockets[thread_slot] = csd;
+                process_socket(thd, ptrans, csd, cs, process_slot, thread_slot);
+                worker_sockets[thread_slot] = NULL;
+            }
+        }
+
+        /* If there are deferred lingering closes, handle them now. */
+        while (!workers_may_exit) {
+            cs = defer_linger_chain;
+            if (!cs) {
+                break;
+            }
+            if (apr_atomic_casptr((void *)&defer_linger_chain, cs->chain,
+                                  cs) != cs) {
+                /* Race lost, try again */
+                continue;
+            }
+            cs->chain = NULL;
+            AP_DEBUG_ASSERT(cs->pub.state == CONN_STATE_LINGER);
+
+            worker_sockets[thread_slot] = csd = cs->pfd.desc.s;
+            process_socket(thd, cs->p, csd, cs, process_slot, thread_slot);
+            worker_sockets[thread_slot] = NULL;
+        }
+    }
+
+    ap_update_child_status_from_indexes(process_slot, thread_slot,
+                                        dying ? SERVER_DEAD
+                                              : SERVER_GRACEFUL, 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 *) ap_malloc(sizeof(proc_info));
+    my_info->pslot = my_child_num;
+    my_info->tslot = -1;      /* listener thread doesn't have a thread slot */
+    rv = ap_thread_create(&ts->listener, thread_attr, listener_thread,
+                          my_info, pruntime);
+    if (rv != APR_SUCCESS) {
+        ap_log_error(APLOG_MARK, APLOG_ALERT, rv, ap_server_conf, APLOGNO(00474)
+                     "ap_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);
+}
+
+static void setup_threads_runtime(void)
+{
+    apr_status_t rv;
+    ap_listen_rec *lr;
+    apr_pool_t *pskip = NULL;
+    int max_recycled_pools = -1, i;
+    const int good_methods[] = { APR_POLLSET_KQUEUE,
+                                 APR_POLLSET_PORT,
+                                 APR_POLLSET_EPOLL };
+    /* XXX: K-A or lingering close connection included in the async factor */
+    const apr_uint32_t async_factor = worker_factor / WORKER_FACTOR_SCALE;
+    const apr_uint32_t pollset_size = (apr_uint32_t)num_listensocks +
+                                      (apr_uint32_t)threads_per_child *
+                                      (async_factor > 2 ? async_factor : 2);
+    int pollset_flags;
+
+    /* Event's skiplist operations will happen concurrently with other modules'
+     * runtime so they need their own pool for allocations, and its lifetime
+     * should be at least the one of the connections (ptrans). Thus pskip is
+     * created as a subpool of pconf like/before ptrans (before so that it's
+     * destroyed after). In forked mode pconf is never destroyed so we are good
+     * anyway, but in ONE_PROCESS mode this ensures that the skiplist works
+     * from connection/ptrans cleanups (even after pchild is destroyed).
+     */
+    apr_pool_create(&pskip, pconf);
+    apr_pool_tag(pskip, "mpm_skiplist");
+    apr_thread_mutex_create(&g_timer_skiplist_mtx, APR_THREAD_MUTEX_DEFAULT, pskip);
+    APR_RING_INIT(&timer_free_ring.link, timer_event_t, link);
+    apr_skiplist_init(&timer_skiplist, pskip);
+    apr_skiplist_set_compare(timer_skiplist, timer_comp, timer_comp);
+
+    /* All threads (listener, workers) and synchronization objects (queues,
+     * pollset, mutexes...) created here should have at least the lifetime of
+     * the connections they handle (i.e. ptrans). We can't use this thread's
+     * self pool because all these objects survive it, nor use pchild or pconf
+     * directly because this starter thread races with other modules' runtime,
+     * nor finally pchild (or subpool thereof) because it is killed explicitly
+     * before pconf (thus connections/ptrans can live longer, which matters in
+     * ONE_PROCESS mode). So this leaves us with a subpool of pconf, created
+     * before any ptrans hence destroyed after.
+     */
+    apr_pool_create(&pruntime, pconf);
+    apr_pool_tag(pruntime, "mpm_runtime");
+
+    /* We must create the fd queues before we start up the listener
+     * and worker threads. */
+    rv = ap_queue_create(&worker_queue, threads_per_child, pruntime);
+    if (rv != APR_SUCCESS) {
+        ap_log_error(APLOG_MARK, APLOG_ALERT, rv, ap_server_conf, APLOGNO(03100)
+                     "ap_queue_create() failed");
+        clean_child_exit(APEXIT_CHILDFATAL);
+    }
+
+    if (ap_max_mem_free != APR_ALLOCATOR_MAX_FREE_UNLIMITED) {
+        /* If we want to conserve memory, let's not keep an unlimited number of
+         * pools & allocators.
+         * XXX: This should probably be a separate config directive
+         */
+        max_recycled_pools = threads_per_child * 3 / 4 ;
+    }
+    rv = ap_queue_info_create(&worker_queue_info, pruntime,
+                              threads_per_child, max_recycled_pools);
+    if (rv != APR_SUCCESS) {
+        ap_log_error(APLOG_MARK, APLOG_ALERT, rv, ap_server_conf, APLOGNO(03101)
+                     "ap_queue_info_create() failed");
+        clean_child_exit(APEXIT_CHILDFATAL);
+    }
+
+    /* Create the timeout mutex and main pollset before the listener
+     * thread starts.
+     */
+    rv = apr_thread_mutex_create(&timeout_mutex, APR_THREAD_MUTEX_DEFAULT,
+                                 pruntime);
+    if (rv != APR_SUCCESS) {
+        ap_log_error(APLOG_MARK, APLOG_ERR, rv, ap_server_conf, APLOGNO(03102)
+                     "creation of the timeout mutex failed.");
+        clean_child_exit(APEXIT_CHILDFATAL);
+    }
+
+    /* Create the main pollset */
+    pollset_flags = APR_POLLSET_THREADSAFE | APR_POLLSET_NOCOPY |
+                    APR_POLLSET_NODEFAULT | APR_POLLSET_WAKEABLE;
+    for (i = 0; i < sizeof(good_methods) / sizeof(good_methods[0]); i++) {
+        rv = apr_pollset_create_ex(&event_pollset, pollset_size, pruntime,
+                                   pollset_flags, good_methods[i]);
+        if (rv == APR_SUCCESS) {
+            listener_is_wakeable = 1;
+            break;
+        }
+    }
+    if (rv != APR_SUCCESS) {
+        pollset_flags &= ~APR_POLLSET_WAKEABLE;
+        for (i = 0; i < sizeof(good_methods) / sizeof(good_methods[0]); i++) {
+            rv = apr_pollset_create_ex(&event_pollset, pollset_size, pruntime,
+                                       pollset_flags, good_methods[i]);
+            if (rv == APR_SUCCESS) {
+                break;
+            }
+        }
+    }
+    if (rv != APR_SUCCESS) {
+        pollset_flags &= ~APR_POLLSET_NODEFAULT;
+        rv = apr_pollset_create(&event_pollset, pollset_size, pruntime,
+                                pollset_flags);
+    }
+    if (rv != APR_SUCCESS) {
+        ap_log_error(APLOG_MARK, APLOG_ERR, rv, ap_server_conf, APLOGNO(03103)
+                     "apr_pollset_create with Thread Safety failed.");
+        clean_child_exit(APEXIT_CHILDFATAL);
+    }
+
+    /* Add listeners to the main pollset */
+    listener_pollfd = apr_pcalloc(pruntime, num_listensocks *
+                                            sizeof(apr_pollfd_t));
+    for (i = 0, lr = my_bucket->listeners; lr; lr = lr->next, i++) {
+        apr_pollfd_t *pfd;
+        listener_poll_type *pt;
+
+        AP_DEBUG_ASSERT(i < num_listensocks);
+        pfd = &listener_pollfd[i];
+
+        pfd->reqevents = APR_POLLIN | APR_POLLHUP | APR_POLLERR;
+        pfd->desc_type = APR_POLL_SOCKET;
+        pfd->desc.s = lr->sd;
+
+        pt = apr_pcalloc(pruntime, sizeof(*pt));
+        pfd->client_data = pt;
+        pt->type = PT_ACCEPT;
+        pt->baton = lr;
+
+        apr_socket_opt_set(pfd->desc.s, APR_SO_NONBLOCK, 1);
+        apr_pollset_add(event_pollset, pfd);
+
+        lr->accept_func = ap_unixd_accept;
+    }
+
+    worker_sockets = apr_pcalloc(pruntime, threads_per_child *
+                                           sizeof(apr_socket_t *));
+}
+
+/* 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 my_child_num = ts->child_num_arg;
+    proc_info *my_info;
+    apr_status_t rv;
+    int threads_created = 0;
+    int listener_started = 0;
+    int prev_threads_created;
+    int loops, i;
+
+    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf, APLOGNO(02471)
+                 "start_threads: Using %s (%swakeable)",
+                 apr_pollset_method_name(event_pollset),
+                 listener_is_wakeable ? "" : "not ");
+
+    loops = prev_threads_created = 0;
+    while (1) {
+        /* threads_per_child does not include the listener thread */
+        for (i = 0; i < threads_per_child; i++) {
+            int status =
+                ap_scoreboard_image->servers[my_child_num][i].status;
+
+            if (status != SERVER_DEAD) {
+                continue;
+            }
+
+            my_info = (proc_info *) ap_malloc(sizeof(proc_info));
+            my_info->pslot = my_child_num;
+            my_info->tslot = i;
+
+            /* 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 = ap_thread_create(&threads[i], thread_attr,
+                                  worker_thread, my_info, pruntime);
+            if (rv != APR_SUCCESS) {
+                ap_log_error(APLOG_MARK, APLOG_ALERT, rv, ap_server_conf,
+                             APLOGNO(03104)
+                             "ap_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 == 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,
+                             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 (!dying) {
+            apr_sleep(apr_time_from_msec(500));
+            if (dying || ++iter > 10) {
+                break;
+            }
+            /* listener has not stopped accepting yet */
+            ap_log_error(APLOG_MARK, APLOG_TRACE1, 0, ap_server_conf,
+                         "listener has not stopped accepting yet (%d iter)", iter);
+            wakeup_listener();
+        }
+        if (iter > 10) {
+            ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf, APLOGNO(00475)
+                         "the listener thread didn't stop accepting");
+        }
+        else {
+            rv = apr_thread_join(&thread_rv, listener);
+            if (rv != APR_SUCCESS) {
+                ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ap_server_conf, APLOGNO(00476)
+                             "apr_thread_join: unable to join listener thread");
+            }
+        }
+    }
+
+    for (i = 0; i < 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, APLOGNO(00477)
+                             "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, APLOGNO(00478)
+                     "apr_thread_join: unable to join the start " "thread");
+    }
+}
+
+static void child_main(int child_num_arg, int child_bucket)
+{
+    apr_thread_t **threads;
+    apr_status_t rv;
+    thread_starter *ts;
+    apr_threadattr_t *thread_attr;
+    apr_thread_t *start_thread_id;
+    int i;
+
+    /* for benefit of any hooks that run as this child initializes */
+    retained->mpm->mpm_state = AP_MPMQ_STARTING;
+
+    ap_my_pid = getpid();
+    ap_child_slot = child_num_arg;
+    ap_fatal_signal_child_setup(ap_server_conf);
+
+    /* Get a sub context for global allocations in this child, so that
+     * we can have cleanups occur when the child exits.
+     */
+    apr_pool_create(&pchild, pconf);
+    apr_pool_tag(pchild, "pchild");
+
+#if AP_HAS_THREAD_LOCAL
+    if (!one_process) {
+        apr_thread_t *thd = NULL;
+        if ((rv = ap_thread_main_create(&thd, pchild))) {
+            ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf, APLOGNO(10377)
+                         "Couldn't initialize child main thread");
+            clean_child_exit(APEXIT_CHILDFATAL);
+        }
+    }
+#endif
+
+    /* close unused listeners and pods */
+    for (i = 0; i < retained->mpm->num_buckets; i++) {
+        if (i != child_bucket) {
+            ap_close_listeners_ex(all_buckets[i].listeners);
+            ap_mpm_podx_close(all_buckets[i].pod);
+        }
+    }
+
+    /*stuff to do before we switch id's, so we have permissions. */
+    ap_reopen_scoreboard(pchild, NULL, 0);
+
+    /* done with init critical section */
+    if (ap_run_drop_privileges(pchild, ap_server_conf)) {
+        clean_child_exit(APEXIT_CHILDFATAL);
+    }
+
+    /* 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. Let's also do this before
+     * child_init() hooks are called and possibly create threads that
+     * otherwise could "steal" (implicitly) MPM's signals.
+     */
+    rv = apr_setup_signal_thread();
+    if (rv != APR_SUCCESS) {
+        ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf, APLOGNO(00479)
+                     "Couldn't initialize signal thread");
+        clean_child_exit(APEXIT_CHILDFATAL);
+    }
+
+    ap_run_child_init(pchild, ap_server_conf);
+
+    if (ap_max_requests_per_child) {
+        conns_this_child = ap_max_requests_per_child;
+    }
+    else {
+        /* coding a value of zero means infinity */
+        conns_this_child = APR_INT32_MAX;
+    }
+
+    /* Setup threads */
+
+    /* Globals used by signal_threads() so to be initialized before */
+    setup_threads_runtime();
+
+    /* 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 = ap_calloc(threads_per_child, sizeof(apr_thread_t *));
+    ts = 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) {
+        rv = apr_threadattr_stacksize_set(thread_attr, ap_thread_stacksize);
+        if (rv != APR_SUCCESS && rv != APR_ENOTIMPL) {
+            ap_log_error(APLOG_MARK, APLOG_WARNING, rv, ap_server_conf, APLOGNO(02436)
+                         "WARNING: ThreadStackSize of %" APR_SIZE_T_FMT " is "
+                         "inappropriate, using default", 
+                         ap_thread_stacksize);
+        }
+    }
+
+    ts->threads = threads;
+    ts->listener = NULL;
+    ts->child_num_arg = child_num_arg;
+    ts->threadattr = thread_attr;
+
+    rv = ap_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, APLOGNO(00480)
+                     "ap_thread_create: unable to create worker thread");
+        /* let the parent decide how bad this really is */
+        clean_child_exit(APEXIT_CHILDSICK);
+    }
+
+    retained->mpm->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 MaxConnectionsPerChild) it will send us SIGTERM
+         */
+        apr_signal(SIGTERM, dummy_signal_handler);
+        unblock_signal(SIGTERM);
+        /* Watch for any messages from the parent over the POD */
+        while (1) {
+            rv = ap_mpm_podx_check(my_bucket->pod);
+            if (rv == AP_MPM_PODX_NORESTART) {
+                /* see if termination was triggered while we slept */
+                switch (terminate_mode) {
+                case ST_GRACEFUL:
+                    rv = AP_MPM_PODX_GRACEFUL;
+                    break;
+                case ST_UNGRACEFUL:
+                    rv = AP_MPM_PODX_RESTART;
+                    break;
+                }
+            }
+            if (rv == AP_MPM_PODX_GRACEFUL || rv == AP_MPM_PODX_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_MPM_PODX_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).
+         */
+        ap_log_error(APLOG_MARK, APLOG_TRACE1, 0, ap_server_conf,
+                     "%s termination received, joining workers",
+                     rv == AP_MPM_PODX_GRACEFUL ? "graceful" : "ungraceful");
+        join_workers(ts->listener, threads);
+        ap_log_error(APLOG_MARK, APLOG_TRACE1, 0, ap_server_conf,
+                     "%s termination, workers joined, exiting",
+                     rv == AP_MPM_PODX_GRACEFUL ? "graceful" : "ungraceful");
+    }
+
+    free(threads);
+
+    clean_child_exit(resource_shortage ? APEXIT_CHILDSICK : 0);
+}
+
+static int make_child(server_rec * s, int slot, int bucket)
+{
+    int pid;
+
+    if (slot + 1 > retained->max_daemon_used) {
+        retained->max_daemon_used = slot + 1;
+    }
+
+    if (ap_scoreboard_image->parent[slot].pid != 0) {
+        /* XXX replace with assert or remove ? */
+        ap_log_error(APLOG_MARK, APLOG_ERR, 0, ap_server_conf, APLOGNO(03455)
+                 "BUG: Scoreboard slot %d should be empty but is "
+                 "in use by pid %" APR_PID_T_FMT,
+                 slot, ap_scoreboard_image->parent[slot].pid);
+        return -1;
+    }
+
+    if (one_process) {
+        my_bucket = &all_buckets[0];
+
+        event_note_child_started(slot, getpid());
+        child_main(slot, 0);
+        /* NOTREACHED */
+        ap_assert(0);
+        return -1;
+    }
+
+    if ((pid = fork()) == -1) {
+        ap_log_error(APLOG_MARK, APLOG_ERR, errno, s, APLOGNO(00481)
+                     "fork: Unable to fork new process");
+
+        /* fork didn't succeed.  There's no need to touch the scoreboard;
+         * if we were trying to replace a failed child process, then
+         * server_main_loop() marked its workers SERVER_DEAD, and if
+         * we were trying to replace a child process that exited normally,
+         * its worker_thread()s left SERVER_DEAD or SERVER_GRACEFUL behind.
+         */
+
+        /* 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) {
+#if AP_HAS_THREAD_LOCAL
+        ap_thread_current_after_fork();
+#endif
+
+        my_bucket = &all_buckets[bucket];
+
+#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_DEBUG, errno,
+                         ap_server_conf, APLOGNO(00482)
+                         "processor unbind failed");
+#endif
+        RAISE_SIGSTOP(MAKE_CHILD);
+
+        apr_signal(SIGTERM, just_die);
+        child_main(slot, bucket);
+        /* NOTREACHED */
+        ap_assert(0);
+        return -1;
+    }
+
+    event_note_child_started(slot, 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 < server_limit; ++i) {
+        if (ap_scoreboard_image->parent[i].pid != 0) {
+            continue;
+        }
+        if (make_child(ap_server_conf, i, i % retained->mpm->num_buckets) < 0) {
+            break;
+        }
+        --number_to_start;
+    }
+}
+
+static void perform_idle_server_maintenance(int child_bucket,
+                                            int *max_daemon_used)
+{
+    int num_buckets = retained->mpm->num_buckets;
+    int idle_thread_count = 0;
+    process_score *ps;
+    int free_length = 0;
+    int free_slots[MAX_SPAWN_RATE];
+    int last_non_dead = -1;
+    int active_thread_count = 0;
+    int i, j;
+
+    for (i = 0; i < server_limit; ++i) {
+        if (num_buckets > 1 && (i % num_buckets) != child_bucket) {
+            /* We only care about child_bucket in this call */
+            continue;
+        }
+        if (i >= retained->max_daemon_used &&
+            free_length == retained->idle_spawn_rate[child_bucket]) {
+            /* short cut if all active processes have been examined and
+             * enough empty scoreboard slots have been found
+             */
+            break;
+        }
+
+        ps = &ap_scoreboard_image->parent[i];
+        if (ps->pid != 0) {
+            int child_threads_active = 0;
+            if (ps->quiescing == 1) {
+                ps->quiescing = 2;
+                retained->active_daemons--;
+                ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf,
+                             "Child %d quiescing: pid %d, gen %d, "
+                             "active %d/%d, total %d/%d/%d",
+                             i, (int)ps->pid, (int)ps->generation,
+                             retained->active_daemons, active_daemons_limit,
+                             retained->total_daemons, retained->max_daemon_used,
+                             server_limit);
+            }
+            for (j = 0; j < threads_per_child; j++) {
+                int status = ap_scoreboard_image->servers[i][j].status;
+
+                /* 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 (status <= SERVER_READY && !ps->quiescing && !ps->not_accepting
+                    && ps->generation == retained->mpm->my_generation) {
+                    ++idle_thread_count;
+                }
+                if (status >= SERVER_READY && status < SERVER_GRACEFUL) {
+                    ++child_threads_active;
+                }
+            }
+            active_thread_count += child_threads_active;
+            if (child_threads_active == threads_per_child) {
+                had_healthy_child = 1;
+            }
+            last_non_dead = i;
+        }
+        else if (free_length < retained->idle_spawn_rate[child_bucket]) {
+            free_slots[free_length++] = i;
+        }
+    }
+    if (*max_daemon_used < last_non_dead + 1) {
+        *max_daemon_used = last_non_dead + 1;
+    }
+
+    if (retained->sick_child_detected) {
+        if (had_healthy_child) {
+            /* Assume this is a transient error, even though it may not be.  Leave
+             * the server up in case it is able to serve some requests or the
+             * problem will be resolved.
+             */
+            retained->sick_child_detected = 0;
+        }
+        else if (child_bucket < num_buckets - 1) {
+            /* check for had_healthy_child up to the last child bucket */
+            return;
+        }
+        else {
+            /* looks like a basket case, as no child ever fully initialized; give up.
+             */
+            retained->mpm->shutdown_pending = 1;
+            child_fatal = 1;
+            ap_log_error(APLOG_MARK, APLOG_ALERT, 0,
+                         ap_server_conf, APLOGNO(02324)
+                         "A resource shortage or other unrecoverable failure "
+                         "was encountered before any child process initialized "
+                         "successfully... httpd is exiting!");
+            /* the child already logged the failure details */
+            return;
+        }
+    }
+
+    AP_DEBUG_ASSERT(retained->active_daemons <= retained->total_daemons
+                    && retained->total_daemons <= retained->max_daemon_used
+                    && retained->max_daemon_used <= server_limit);
+
+    if (idle_thread_count > max_spare_threads / num_buckets) {
+        /*
+         * Child processes that we ask to shut down won't die immediately
+         * but may stay around for a long time when they finish their
+         * requests. If the server load changes many times, many such
+         * gracefully finishing processes may accumulate, filling up the
+         * scoreboard. To avoid running out of scoreboard entries, we
+         * don't shut down more processes if there are stopping ones
+         * already (i.e. active_daemons != total_daemons) and not enough
+         * slack space in the scoreboard for a graceful restart.
+         *
+         * XXX It would be nice if we could
+         * XXX - kill processes without keepalive connections first
+         * XXX - tell children to stop accepting new connections, and
+         * XXX   depending on server load, later be able to resurrect them
+         *       or kill them
+         */
+        int do_kill = (retained->active_daemons == retained->total_daemons
+                       || (server_limit - retained->total_daemons >
+                           active_daemons_limit));
+        ap_log_error(APLOG_MARK, APLOG_TRACE5, 0, ap_server_conf,
+                     "%shutting down one child: "
+                     "active %d/%d, total %d/%d/%d, "
+                     "idle threads %d, max workers %d",
+                     (do_kill) ? "S" : "Not s",
+                     retained->active_daemons, active_daemons_limit,
+                     retained->total_daemons, retained->max_daemon_used,
+                     server_limit, idle_thread_count, max_workers);
+        if (do_kill) {
+            ap_mpm_podx_signal(all_buckets[child_bucket].pod,
+                               AP_MPM_PODX_GRACEFUL);
+        }
+        else {
+            /* Wait for dying daemon(s) to exit */
+        }
+        retained->idle_spawn_rate[child_bucket] = 1;
+    }
+    else if (idle_thread_count < min_spare_threads / num_buckets) {
+        if (active_thread_count >= max_workers / num_buckets) {
+            if (0 == idle_thread_count) { 
+                if (!retained->maxclients_reported) {
+                    ap_log_error(APLOG_MARK, APLOG_ERR, 0, ap_server_conf, APLOGNO(00484)
+                                 "server reached MaxRequestWorkers setting, "
+                                 "consider raising the MaxRequestWorkers "
+                                 "setting");
+                    retained->maxclients_reported = 1;
+                }
+             }
+             else { 
+                if (!retained->near_maxclients_reported) {
+                    ap_log_error(APLOG_MARK, APLOG_ERR, 0, ap_server_conf, APLOGNO(10159)
+                            "server is within MinSpareThreads of "
+                            "MaxRequestWorkers, consider raising the "
+                            "MaxRequestWorkers setting");
+                    retained->near_maxclients_reported = 1;
+                }
+            }
+            retained->idle_spawn_rate[child_bucket] = 1;
+        }
+        else if (free_length == 0) { /* scoreboard is full, can't fork */
+            ap_log_error(APLOG_MARK, APLOG_ERR, 0, ap_server_conf, APLOGNO(03490)
+                         "scoreboard is full, not at MaxRequestWorkers."
+                         "Increase ServerLimit.");
+            retained->idle_spawn_rate[child_bucket] = 1;
+        }
+        else {
+            if (free_length > retained->idle_spawn_rate[child_bucket]) {
+                free_length = retained->idle_spawn_rate[child_bucket];
+            }
+            if (free_length + retained->active_daemons > active_daemons_limit) {
+                if (retained->active_daemons < active_daemons_limit) {
+                    free_length = active_daemons_limit - retained->active_daemons;
+                }
+                else {
+                    ap_log_error(APLOG_MARK, APLOG_TRACE1, 0, ap_server_conf,
+                                 "server is at active daemons limit, spawning "
+                                 "of %d children cancelled: active %d/%d, "
+                                 "total %d/%d/%d, rate %d", free_length,
+                                 retained->active_daemons, active_daemons_limit,
+                                 retained->total_daemons, retained->max_daemon_used,
+                                 server_limit, retained->idle_spawn_rate[child_bucket]);
+                    /* reset the spawning rate and prevent its growth below */
+                    retained->idle_spawn_rate[child_bucket] = 1;
+                    ++retained->hold_off_on_exponential_spawning;
+                    free_length = 0;
+                }
+            }
+            if (retained->idle_spawn_rate[child_bucket] >= 8) {
+                ap_log_error(APLOG_MARK, APLOG_INFO, 0, ap_server_conf, APLOGNO(00486)
+                             "server seems busy, (you may need "
+                             "to increase StartServers, ThreadsPerChild "
+                             "or Min/MaxSpareThreads), "
+                             "spawning %d children, there are around %d idle "
+                             "threads, %d active children, and %d children "
+                             "that are shutting down", free_length,
+                             idle_thread_count, retained->active_daemons,
+                             retained->total_daemons);
+            }
+            for (i = 0; i < free_length; ++i) {
+                int slot = free_slots[i];
+                if (make_child(ap_server_conf, slot, child_bucket) < 0) {
+                    continue;
+                }
+                if (*max_daemon_used < slot + 1) {
+                    *max_daemon_used = slot + 1;
+                }
+            }
+            /* 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 (retained->hold_off_on_exponential_spawning) {
+                --retained->hold_off_on_exponential_spawning;
+            }
+            else if (retained->idle_spawn_rate[child_bucket]
+                     < MAX_SPAWN_RATE / num_buckets) {
+                retained->idle_spawn_rate[child_bucket] *= 2;
+            }
+        }
+    }
+    else {
+        retained->idle_spawn_rate[child_bucket] = 1;
+    }
+}
+
+static void server_main_loop(int remaining_children_to_start)
+{
+    int num_buckets = retained->mpm->num_buckets;
+    int max_daemon_used = 0;
+    int successive_kills = 0;
+    int child_slot;
+    apr_exit_why_e exitwhy;
+    int status, processed_status;
+    apr_proc_t pid;
+    int i;
+
+    while (!retained->mpm->restart_pending && !retained->mpm->shutdown_pending) {
+        ap_wait_or_timeout(&exitwhy, &status, &pid, pconf, ap_server_conf);
+
+        if (pid.pid != -1) {
+            processed_status = ap_process_child_status(&pid, exitwhy, status);
+            child_slot = ap_find_child_by_pid(&pid);
+            if (processed_status == APEXIT_CHILDFATAL) {
+                /* fix race condition found in PR 39311
+                 * A child created at the same time as a graceful happens 
+                 * can find the lock missing and create a fatal error.
+                 * It is not fatal for the last generation to be in this state.
+                 */
+                if (child_slot < 0
+                    || ap_get_scoreboard_process(child_slot)->generation
+                       == retained->mpm->my_generation) {
+                    retained->mpm->shutdown_pending = 1;
+                    child_fatal = 1;
+                    /*
+                     * total_daemons counting will be off now, but as we
+                     * are shutting down, that is not an issue anymore.
+                     */
+                    return;
+                }
+                else {
+                    ap_log_error(APLOG_MARK, APLOG_WARNING, 0, ap_server_conf, APLOGNO(00487)
+                                 "Ignoring fatal error in child of previous "
+                                 "generation (pid %ld).",
+                                 (long)pid.pid);
+                    retained->sick_child_detected = 1;
+                }
+            }
+            else if (processed_status == APEXIT_CHILDSICK) {
+                /* tell perform_idle_server_maintenance to check into this
+                 * on the next timer pop
+                 */
+                retained->sick_child_detected = 1;
+            }
+            /* non-fatal death... note that it's gone in the scoreboard. */
+            if (child_slot >= 0) {
+                event_note_child_stopped(child_slot, 0, 0);
+
+                if (processed_status == APEXIT_CHILDSICK) {
+                    /* resource shortage, minimize the fork rate */
+                    retained->idle_spawn_rate[child_slot % num_buckets] = 1;
+                }
+                else if (remaining_children_to_start) {
+                    /* we're still doing a 1-for-1 replacement of dead
+                     * children with new children
+                     */
+                    make_child(ap_server_conf, child_slot,
+                               child_slot % num_buckets);
+                    --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 (retained->mpm->was_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, APLOGNO(00488)
+                             "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.  If a child is
+             * killed by a signal (faulting) we want to restart it ASAP
+             * though, up to 3 successive faults or we stop this until
+             * a timeout happens again (to avoid the flood of fork()ed
+             * processes that keep being killed early).
+             */
+            if (child_slot < 0 || !APR_PROC_CHECK_SIGNALED(exitwhy)) {
+                continue;
+            }
+            if (++successive_kills >= 3) {
+                if (successive_kills % 10 == 3) {
+                    ap_log_error(APLOG_MARK, APLOG_WARNING, 0,
+                                 ap_server_conf, APLOGNO(10392)
+                                 "children are killed successively!");
+                }
+                continue;
+            }
+            ++remaining_children_to_start;
+        }
+        else {
+            successive_kills = 0;
+        }
+
+        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;
+        }
+
+        max_daemon_used = 0;
+        for (i = 0; i < num_buckets; i++) {
+            perform_idle_server_maintenance(i, &max_daemon_used);
+        }
+        retained->max_daemon_used = max_daemon_used;
+    }
+}
+
+static int event_run(apr_pool_t * _pconf, apr_pool_t * plog, server_rec * s)
+{
+    int num_buckets = retained->mpm->num_buckets;
+    int remaining_children_to_start;
+    int i;
+
+    ap_log_pid(pconf, ap_pid_fname);
+
+    if (!retained->mpm->was_graceful) {
+        if (ap_run_pre_mpm(s->process->pool, SB_SHARED) != OK) {
+            retained->mpm->mpm_state = AP_MPMQ_STOPPING;
+            return !OK;
+        }
+        /* fix the generation number in the global score; we just got a new,
+         * cleared scoreboard
+         */
+        ap_scoreboard_image->global->running_generation = retained->mpm->my_generation;
+    }
+
+    ap_unixd_mpm_set_signals(pconf, one_process);
+
+    /* Don't thrash since num_buckets depends on the
+     * system and the number of online CPU cores...
+     */
+    if (active_daemons_limit < num_buckets)
+        active_daemons_limit = num_buckets;
+    if (ap_daemons_to_start < num_buckets)
+        ap_daemons_to_start = num_buckets;
+    /* We want to create as much children at a time as the number of buckets,
+     * so to optimally accept connections (evenly distributed across buckets).
+     * Thus min_spare_threads should at least maintain num_buckets children,
+     * and max_spare_threads allow num_buckets more children w/o triggering
+     * immediately (e.g. num_buckets idle threads margin, one per bucket).
+     */
+    if (min_spare_threads < threads_per_child * (num_buckets - 1) + num_buckets)
+        min_spare_threads = threads_per_child * (num_buckets - 1) + num_buckets;
+    if (max_spare_threads < min_spare_threads + (threads_per_child + 1) * num_buckets)
+        max_spare_threads = min_spare_threads + (threads_per_child + 1) * num_buckets;
+
+    /* 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 may start a new one, until
+     * there are at least min_spare_threads idle threads, counting across
+     * all children.  But we may be permitted to start more children 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 > active_daemons_limit) {
+        remaining_children_to_start = active_daemons_limit;
+    }
+    if (!retained->mpm->was_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 */
+        retained->hold_off_on_exponential_spawning = 10;
+    }
+
+    ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, ap_server_conf, APLOGNO(00489)
+                 "%s configured -- resuming normal operations",
+                 ap_get_server_description());
+    ap_log_error(APLOG_MARK, APLOG_INFO, 0, ap_server_conf, APLOGNO(00490)
+                 "Server built: %s", ap_get_server_built());
+    ap_log_command_line(plog, s);
+    ap_log_mpm_common(s);
+
+    retained->mpm->mpm_state = AP_MPMQ_RUNNING;
+
+    server_main_loop(remaining_children_to_start);
+    retained->mpm->mpm_state = AP_MPMQ_STOPPING;
+
+    if (retained->mpm->shutdown_pending && retained->mpm->is_ungraceful) {
+        /* Time to shut down:
+         * Kill child processes, tell them to call child_exit, etc...
+         */
+        for (i = 0; i < num_buckets; i++) {
+            ap_mpm_podx_killpg(all_buckets[i].pod, active_daemons_limit,
+                               AP_MPM_PODX_RESTART);
+        }
+        ap_reclaim_child_processes(1, /* Start with SIGTERM */
+                                   event_note_child_stopped);
+
+        if (!child_fatal) {
+            /* cleanup pid file on normal shutdown */
+            ap_remove_pid(pconf, ap_pid_fname);
+            ap_log_error(APLOG_MARK, APLOG_NOTICE, 0,
+                         ap_server_conf, APLOGNO(00491) "caught SIGTERM, shutting down");
+        }
+
+        return DONE;
+    }
+
+    if (retained->mpm->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();
+        for (i = 0; i < num_buckets; i++) {
+            ap_mpm_podx_killpg(all_buckets[i].pod, active_daemons_limit,
+                               AP_MPM_PODX_GRACEFUL);
+        }
+        ap_relieve_child_processes(event_note_child_stopped);
+
+        if (!child_fatal) {
+            /* cleanup pid file on normal shutdown */
+            ap_remove_pid(pconf, ap_pid_fname);
+            ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, ap_server_conf, APLOGNO(00492)
+                         "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 */
+        retained->mpm->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(event_note_child_stopped);
+
+            active_children = 0;
+            for (index = 0; index < retained->max_daemon_used; ++index) {
+                if (ap_mpm_safe_kill(MPM_CHILD_PID(index), 0) == APR_SUCCESS) {
+                    active_children = 1;
+                    /* Having just one child is enough to stay around */
+                    break;
+                }
+            }
+        } while (!retained->mpm->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.
+         */
+        for (i = 0; i < num_buckets; i++) {
+            ap_mpm_podx_killpg(all_buckets[i].pod, active_daemons_limit,
+                               AP_MPM_PODX_RESTART);
+        }
+        ap_reclaim_child_processes(1, event_note_child_stopped);
+
+        return DONE;
+    }
+
+    /* we've been told to restart */
+    if (one_process) {
+        /* not worth thinking about */
+        return DONE;
+    }
+
+    /* 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.
+     */
+    ++retained->mpm->my_generation;
+    ap_scoreboard_image->global->running_generation = retained->mpm->my_generation;
+
+    if (!retained->mpm->is_ungraceful) {
+        ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, ap_server_conf, APLOGNO(00493)
+                     AP_SIG_GRACEFUL_STRING " received.  Doing graceful restart");
+        /* wake up the children...time to die.  But we'll have more soon */
+        for (i = 0; i < num_buckets; i++) {
+            ap_mpm_podx_killpg(all_buckets[i].pod, active_daemons_limit,
+                               AP_MPM_PODX_GRACEFUL);
+        }
+
+        /* This is mostly for debugging... so that we know what is still
+         * gracefully dealing with existing request.
+         */
+
+    }
+    else {
+        ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, ap_server_conf, APLOGNO(00494)
+                     "SIGHUP received.  Attempting to restart");
+        /* 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.
+         */
+        for (i = 0; i < num_buckets; i++) {
+            ap_mpm_podx_killpg(all_buckets[i].pod, active_daemons_limit,
+                               AP_MPM_PODX_RESTART);
+        }
+
+        ap_reclaim_child_processes(1,  /* Start with SIGTERM */
+                                   event_note_child_stopped);
+    }
+
+    return OK;
+}
+
+static void setup_slave_conn(conn_rec *c, void *csd) 
+{
+    event_conn_state_t *mcs;
+    event_conn_state_t *cs;
+    
+    mcs = ap_get_module_config(c->master->conn_config, &mpm_event_module);
+    
+    cs = apr_pcalloc(c->pool, sizeof(*cs));
+    cs->c = c;
+    cs->r = NULL;
+    cs->sc = mcs->sc;
+    cs->suspended = 0;
+    cs->p = c->pool;
+    cs->bucket_alloc = c->bucket_alloc;
+    cs->pfd = mcs->pfd;
+    cs->pub = mcs->pub;
+    cs->pub.state = CONN_STATE_READ_REQUEST_LINE;
+    cs->pub.sense = CONN_SENSE_DEFAULT;
+    
+    c->cs = &(cs->pub);
+    ap_set_module_config(c->conn_config, &mpm_event_module, cs);
+}
+
+static int event_pre_connection(conn_rec *c, void *csd)
+{
+    if (c->master && (!c->cs || c->cs == c->master->cs)) {
+        setup_slave_conn(c, csd);
+    }
+    return OK;
+}
+
+static int event_protocol_switch(conn_rec *c, request_rec *r, server_rec *s,
+                                 const char *protocol)
+{
+    if (!r && s) {
+        /* connection based switching of protocol, set the correct server
+         * configuration, so that timeouts, keepalives and such are used
+         * for the server that the connection was switched on.
+         * Normally, we set this on post_read_request, but on a protocol
+         * other than http/1.1, this might never happen.
+         */
+        event_conn_state_t *cs;
+        
+        cs = ap_get_module_config(c->conn_config, &mpm_event_module);
+        cs->sc = ap_get_module_config(s->module_config, &mpm_event_module);
+    }
+    return DECLINED;
+}
+
+/* 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 event_open_logs(apr_pool_t * p, apr_pool_t * plog,
+                           apr_pool_t * ptemp, server_rec * s)
+{
+    int startup = 0;
+    int level_flags = 0;
+    int num_buckets = 0;
+    ap_listen_rec **listen_buckets;
+    apr_status_t rv;
+    int i;
+
+    pconf = p;
+
+    /* the reverse of pre_config, we want this only the first time around */
+    if (retained->mpm->module_loads == 1) {
+        startup = 1;
+        level_flags |= APLOG_STARTUP;
+    }
+
+    if ((num_listensocks = ap_setup_listeners(ap_server_conf)) < 1) {
+        ap_log_error(APLOG_MARK, APLOG_ALERT | level_flags, 0,
+                     (startup ? NULL : s),
+                     "no listening sockets available, shutting down");
+        return !OK;
+    }
+
+    if (one_process) {
+        num_buckets = 1;
+    }
+    else if (retained->mpm->was_graceful) {
+        /* Preserve the number of buckets on graceful restarts. */
+        num_buckets = retained->mpm->num_buckets;
+    }
+    if ((rv = ap_duplicate_listeners(pconf, ap_server_conf,
+                                     &listen_buckets, &num_buckets))) {
+        ap_log_error(APLOG_MARK, APLOG_CRIT | level_flags, rv,
+                     (startup ? NULL : s),
+                     "could not duplicate listeners");
+        return !OK;
+    }
+
+    all_buckets = apr_pcalloc(pconf, num_buckets * sizeof(*all_buckets));
+    for (i = 0; i < num_buckets; i++) {
+        if (!one_process && /* no POD in one_process mode */
+                (rv = ap_mpm_podx_open(pconf, &all_buckets[i].pod))) {
+            ap_log_error(APLOG_MARK, APLOG_CRIT | level_flags, rv,
+                         (startup ? NULL : s),
+                         "could not open pipe-of-death");
+            return !OK;
+        }
+        all_buckets[i].listeners = listen_buckets[i];
+    }
+
+    if (retained->mpm->max_buckets < num_buckets) {
+        int new_max, *new_ptr;
+        new_max = retained->mpm->max_buckets * 2;
+        if (new_max < num_buckets) {
+            new_max = num_buckets;
+        }
+        new_ptr = (int *)apr_palloc(ap_pglobal, new_max * sizeof(int));
+        if (retained->idle_spawn_rate) /* NULL at startup */
+            memcpy(new_ptr, retained->idle_spawn_rate,
+                   retained->mpm->num_buckets * sizeof(int));
+        retained->idle_spawn_rate = new_ptr;
+        retained->mpm->max_buckets = new_max;
+    }
+    if (retained->mpm->num_buckets < num_buckets) {
+        int rate_max = 1;
+        /* If new buckets are added, set their idle spawn rate to
+         * the highest so far, so that they get filled as quickly
+         * as the existing ones.
+         */
+        for (i = 0; i < retained->mpm->num_buckets; i++) {
+            if (rate_max < retained->idle_spawn_rate[i]) {
+                rate_max = retained->idle_spawn_rate[i];
+            }
+        }
+        for (/* up to date i */; i < num_buckets; i++) {
+            retained->idle_spawn_rate[i] = rate_max;
+        }
+    }
+    retained->mpm->num_buckets = num_buckets;
+
+    /* for skiplist */
+    srand((unsigned int)apr_time_now());
+    return OK;
+}
+
+static int event_pre_config(apr_pool_t * pconf, apr_pool_t * plog,
+                            apr_pool_t * ptemp)
+{
+    int no_detach, debug, foreground;
+    apr_status_t rv;
+    const char *userdata_key = "mpm_event_module";
+    int test_atomics = 0;
+
+    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");
+    }
+
+    retained = ap_retained_data_get(userdata_key);
+    if (!retained) {
+        retained = ap_retained_data_create(userdata_key, sizeof(*retained));
+        retained->mpm = ap_unixd_mpm_get_retained_data();
+        if (retained->mpm->module_loads) {
+            test_atomics = 1;
+        }
+    }
+    retained->mpm->mpm_state = AP_MPMQ_STARTING;
+    if (retained->mpm->baton != retained) {
+        retained->mpm->was_graceful = 0;
+        retained->mpm->baton = retained;
+    }
+    ++retained->mpm->module_loads;
+
+    /* test once for correct operation of fdqueue */
+    if (test_atomics || retained->mpm->module_loads == 2) {
+        static apr_uint32_t foo1, foo2;
+
+        apr_atomic_set32(&foo1, 100);
+        foo2 = apr_atomic_add32(&foo1, -10);
+        if (foo2 != 100 || foo1 != 90) {
+            ap_log_error(APLOG_MARK, APLOG_CRIT, 0, NULL, APLOGNO(02405)
+                         "atomics not working as expected - add32 of negative number");
+            return HTTP_INTERNAL_SERVER_ERROR;
+        }
+    }
+
+    /* sigh, want this only the second time around */
+    if (retained->mpm->module_loads == 2) {
+        rv = apr_pollset_create(&event_pollset, 1, plog,
+                                APR_POLLSET_THREADSAFE | APR_POLLSET_NOCOPY);
+        if (rv != APR_SUCCESS) {
+            ap_log_error(APLOG_MARK, APLOG_CRIT, rv, NULL, APLOGNO(00495)
+                         "Couldn't create a Thread Safe Pollset. "
+                         "Is it supported on your platform?"
+                         "Also check system or user limits!");
+            return HTTP_INTERNAL_SERVER_ERROR;
+        }
+        apr_pollset_destroy(event_pollset);
+
+        if (!one_process && !foreground) {
+            /* before we detach, setup crash handlers to log to errorlog */
+            ap_fatal_signal_setup(ap_server_conf, pconf);
+            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, APLOGNO(00496)
+                             "apr_proc_detach failed");
+                return HTTP_INTERNAL_SERVER_ERROR;
+            }
+        }
+    }
+
+    parent_pid = ap_my_pid = getpid();
+
+    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;
+    server_limit = DEFAULT_SERVER_LIMIT;
+    thread_limit = DEFAULT_THREAD_LIMIT;
+    active_daemons_limit = server_limit;
+    threads_per_child = DEFAULT_THREADS_PER_CHILD;
+    max_workers = active_daemons_limit * threads_per_child;
+    defer_linger_chain = NULL;
+    had_healthy_child = 0;
+    ap_extended_status = 0;
+
+    event_pollset = NULL;
+    worker_queue_info = NULL;
+    listener_os_thread = NULL;
+    listensocks_disabled = 0;
+    listener_is_wakeable = 0;
+
+    return OK;
+}
+
+static int event_post_config(apr_pool_t *pconf, apr_pool_t *plog,
+                             apr_pool_t *ptemp, server_rec *s)
+{
+    struct {
+        struct timeout_queue *tail, *q;
+        apr_hash_t *hash;
+    } wc, ka;
+
+    /* Not needed in pre_config stage */
+    if (ap_state_query(AP_SQ_MAIN_STATE) == AP_SQ_MS_CREATE_PRE_CONFIG) {
+        return OK;
+    }
+
+    wc.tail = ka.tail = NULL;
+    wc.hash = apr_hash_make(ptemp);
+    ka.hash = apr_hash_make(ptemp);
+
+    linger_q = TO_QUEUE_MAKE(pconf, apr_time_from_sec(MAX_SECS_TO_LINGER),
+                             NULL);
+    short_linger_q = TO_QUEUE_MAKE(pconf, apr_time_from_sec(SECONDS_TO_LINGER),
+                                   NULL);
+
+    for (; s; s = s->next) {
+        event_srv_cfg *sc = apr_pcalloc(pconf, sizeof *sc);
+
+        ap_set_module_config(s->module_config, &mpm_event_module, sc);
+        if (!wc.tail) {
+            /* The main server uses the global queues */
+            wc.q = TO_QUEUE_MAKE(pconf, s->timeout, NULL);
+            apr_hash_set(wc.hash, &s->timeout, sizeof s->timeout, wc.q);
+            wc.tail = write_completion_q = wc.q;
+
+            ka.q = TO_QUEUE_MAKE(pconf, s->keep_alive_timeout, NULL);
+            apr_hash_set(ka.hash, &s->keep_alive_timeout,
+                         sizeof s->keep_alive_timeout, ka.q);
+            ka.tail = keepalive_q = ka.q;
+        }
+        else {
+            /* The vhosts use any existing queue with the same timeout,
+             * or their own queue(s) if there isn't */
+            wc.q = apr_hash_get(wc.hash, &s->timeout, sizeof s->timeout);
+            if (!wc.q) {
+                wc.q = TO_QUEUE_MAKE(pconf, s->timeout, wc.tail);
+                apr_hash_set(wc.hash, &s->timeout, sizeof s->timeout, wc.q);
+                wc.tail = wc.tail->next = wc.q;
+            }
+
+            ka.q = apr_hash_get(ka.hash, &s->keep_alive_timeout,
+                                sizeof s->keep_alive_timeout);
+            if (!ka.q) {
+                ka.q = TO_QUEUE_MAKE(pconf, s->keep_alive_timeout, ka.tail);
+                apr_hash_set(ka.hash, &s->keep_alive_timeout,
+                             sizeof s->keep_alive_timeout, ka.q);
+                ka.tail = ka.tail->next = ka.q;
+            }
+        }
+        sc->wc_q = wc.q;
+        sc->ka_q = ka.q;
+    }
+
+    return OK;
+}
+
+static int event_check_config(apr_pool_t *p, apr_pool_t *plog,
+                              apr_pool_t *ptemp, server_rec *s)
+{
+    int startup = 0;
+
+    /* the reverse of pre_config, we want this only the first time around */
+    if (retained->mpm->module_loads == 1) {
+        startup = 1;
+    }
+
+    if (server_limit > MAX_SERVER_LIMIT) {
+        if (startup) {
+            ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL, APLOGNO(00497)
+                         "WARNING: ServerLimit of %d exceeds compile-time "
+                         "limit of %d servers, decreasing to %d.",
+                         server_limit, MAX_SERVER_LIMIT, MAX_SERVER_LIMIT);
+        } else {
+            ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, APLOGNO(00498)
+                         "ServerLimit of %d exceeds compile-time limit "
+                         "of %d, decreasing to match",
+                         server_limit, MAX_SERVER_LIMIT);
+        }
+        server_limit = MAX_SERVER_LIMIT;
+    }
+    else if (server_limit < 1) {
+        if (startup) {
+            ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL, APLOGNO(00499)
+                         "WARNING: ServerLimit of %d not allowed, "
+                         "increasing to 1.", server_limit);
+        } else {
+            ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, APLOGNO(00500)
+                         "ServerLimit of %d not allowed, increasing to 1",
+                         server_limit);
+        }
+        server_limit = 1;
+    }
+
+    /* you cannot change ServerLimit across a restart; ignore
+     * any such attempts
+     */
+    if (!retained->first_server_limit) {
+        retained->first_server_limit = server_limit;
+    }
+    else if (server_limit != retained->first_server_limit) {
+        /* don't need a startup console version here */
+        ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, APLOGNO(00501)
+                     "changing ServerLimit to %d from original value of %d "
+                     "not allowed during restart",
+                     server_limit, retained->first_server_limit);
+        server_limit = retained->first_server_limit;
+    }
+
+    if (thread_limit > MAX_THREAD_LIMIT) {
+        if (startup) {
+            ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL, APLOGNO(00502)
+                         "WARNING: ThreadLimit of %d exceeds compile-time "
+                         "limit of %d threads, decreasing to %d.",
+                         thread_limit, MAX_THREAD_LIMIT, MAX_THREAD_LIMIT);
+        } else {
+            ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, APLOGNO(00503)
+                         "ThreadLimit of %d exceeds compile-time limit "
+                         "of %d, decreasing to match",
+                         thread_limit, MAX_THREAD_LIMIT);
+        }
+        thread_limit = MAX_THREAD_LIMIT;
+    }
+    else if (thread_limit < 1) {
+        if (startup) {
+            ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL, APLOGNO(00504)
+                         "WARNING: ThreadLimit of %d not allowed, "
+                         "increasing to 1.", thread_limit);
+        } else {
+            ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, APLOGNO(00505)
+                         "ThreadLimit of %d not allowed, increasing to 1",
+                         thread_limit);
+        }
+        thread_limit = 1;
+    }
+
+    /* you cannot change ThreadLimit across a restart; ignore
+     * any such attempts
+     */
+    if (!retained->first_thread_limit) {
+        retained->first_thread_limit = thread_limit;
+    }
+    else if (thread_limit != retained->first_thread_limit) {
+        /* don't need a startup console version here */
+        ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, APLOGNO(00506)
+                     "changing ThreadLimit to %d from original value of %d "
+                     "not allowed during restart",
+                     thread_limit, retained->first_thread_limit);
+        thread_limit = retained->first_thread_limit;
+    }
+
+    if (threads_per_child > thread_limit) {
+        if (startup) {
+            ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL, APLOGNO(00507)
+                         "WARNING: ThreadsPerChild of %d exceeds ThreadLimit "
+                         "of %d threads, decreasing to %d. "
+                         "To increase, please see the ThreadLimit directive.",
+                         threads_per_child, thread_limit, thread_limit);
+        } else {
+            ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, APLOGNO(00508)
+                         "ThreadsPerChild of %d exceeds ThreadLimit "
+                         "of %d, decreasing to match",
+                         threads_per_child, thread_limit);
+        }
+        threads_per_child = thread_limit;
+    }
+    else if (threads_per_child < 1) {
+        if (startup) {
+            ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL, APLOGNO(00509)
+                         "WARNING: ThreadsPerChild of %d not allowed, "
+                         "increasing to 1.", threads_per_child);
+        } else {
+            ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, APLOGNO(00510)
+                         "ThreadsPerChild of %d not allowed, increasing to 1",
+                         threads_per_child);
+        }
+        threads_per_child = 1;
+    }
+
+    if (max_workers < threads_per_child) {
+        if (startup) {
+            ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL, APLOGNO(00511)
+                         "WARNING: MaxRequestWorkers of %d is less than "
+                         "ThreadsPerChild of %d, increasing to %d. "
+                         "MaxRequestWorkers must be at least as large "
+                         "as the number of threads in a single server.",
+                         max_workers, threads_per_child, threads_per_child);
+        } else {
+            ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, APLOGNO(00512)
+                         "MaxRequestWorkers of %d is less than ThreadsPerChild "
+                         "of %d, increasing to match",
+                         max_workers, threads_per_child);
+        }
+        max_workers = threads_per_child;
+    }
+
+    active_daemons_limit = max_workers / threads_per_child;
+
+    if (max_workers % threads_per_child) {
+        int tmp_max_workers = active_daemons_limit * threads_per_child;
+
+        if (startup) {
+            ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL, APLOGNO(00513)
+                         "WARNING: MaxRequestWorkers of %d is not an integer "
+                         "multiple of ThreadsPerChild of %d, decreasing to nearest "
+                         "multiple %d, for a maximum of %d servers.",
+                         max_workers, threads_per_child, tmp_max_workers,
+                         active_daemons_limit);
+        } else {
+            ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, APLOGNO(00514)
+                         "MaxRequestWorkers of %d is not an integer multiple "
+                         "of ThreadsPerChild of %d, decreasing to nearest "
+                         "multiple %d", max_workers, threads_per_child,
+                         tmp_max_workers);
+        }
+        max_workers = tmp_max_workers;
+    }
+
+    if (active_daemons_limit > server_limit) {
+        if (startup) {
+            ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL, APLOGNO(00515)
+                         "WARNING: MaxRequestWorkers of %d would require %d servers "
+                         "and would exceed ServerLimit of %d, decreasing to %d. "
+                         "To increase, please see the ServerLimit directive.",
+                         max_workers, active_daemons_limit, server_limit,
+                         server_limit * threads_per_child);
+        } else {
+            ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, APLOGNO(00516)
+                         "MaxRequestWorkers of %d would require %d servers and "
+                         "exceed ServerLimit of %d, decreasing to %d",
+                         max_workers, active_daemons_limit, server_limit,
+                         server_limit * threads_per_child);
+        }
+        active_daemons_limit = server_limit;
+    }
+
+    /* ap_daemons_to_start > active_daemons_limit checked in ap_mpm_run() */
+    if (ap_daemons_to_start < 1) {
+        if (startup) {
+            ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL, APLOGNO(00517)
+                         "WARNING: StartServers of %d not allowed, "
+                         "increasing to 1.", ap_daemons_to_start);
+        } else {
+            ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, APLOGNO(00518)
+                         "StartServers of %d not allowed, increasing to 1",
+                         ap_daemons_to_start);
+        }
+        ap_daemons_to_start = 1;
+    }
+
+    if (min_spare_threads < 1) {
+        if (startup) {
+            ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL, APLOGNO(00519)
+                         "WARNING: MinSpareThreads of %d not allowed, "
+                         "increasing to 1 to avoid almost certain server "
+                         "failure. Please read the documentation.",
+                         min_spare_threads);
+        } else {
+            ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, APLOGNO(00520)
+                         "MinSpareThreads of %d not allowed, increasing to 1",
+                         min_spare_threads);
+        }
+        min_spare_threads = 1;
+    }
+
+    /* max_spare_threads < min_spare_threads + threads_per_child
+     * checked in ap_mpm_run()
+     */
+
+    return OK;
+}
+
+static void event_hooks(apr_pool_t * p)
+{
+    /* Our open_logs hook function 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(event_open_logs, NULL, aszSucc, APR_HOOK_REALLY_FIRST);
+    /* 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(event_pre_config, NULL, NULL, APR_HOOK_REALLY_FIRST);
+    ap_hook_post_config(event_post_config, NULL, NULL, APR_HOOK_MIDDLE);
+    ap_hook_check_config(event_check_config, NULL, NULL, APR_HOOK_MIDDLE);
+    ap_hook_mpm(event_run, NULL, NULL, APR_HOOK_MIDDLE);
+    ap_hook_mpm_query(event_query, NULL, NULL, APR_HOOK_MIDDLE);
+    ap_hook_mpm_register_timed_callback(event_register_timed_callback, NULL, NULL,
+                                        APR_HOOK_MIDDLE);
+    ap_hook_pre_read_request(event_pre_read_request, NULL, NULL, APR_HOOK_MIDDLE);
+    ap_hook_post_read_request(event_post_read_request, NULL, NULL, APR_HOOK_MIDDLE);
+    ap_hook_mpm_get_name(event_get_name, NULL, NULL, APR_HOOK_MIDDLE);
+
+    ap_hook_pre_connection(event_pre_connection, NULL, NULL, APR_HOOK_REALLY_FIRST);
+    ap_hook_protocol_switch(event_protocol_switch, 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);
+    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_workers(cmd_parms * cmd, void *dummy,
+                                   const char *arg)
+{
+    const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
+    if (err != NULL) {
+        return err;
+    }
+    if (!strcasecmp(cmd->cmd->name, "MaxClients")) {
+        ap_log_error(APLOG_MARK, APLOG_INFO, 0, NULL, APLOGNO(00521)
+                     "MaxClients is deprecated, use MaxRequestWorkers "
+                     "instead.");
+    }
+    max_workers = atoi(arg);
+    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;
+    }
+
+    threads_per_child = atoi(arg);
+    return NULL;
+}
+static const char *set_server_limit (cmd_parms *cmd, void *dummy, const char *arg)
+{
+    const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
+    if (err != NULL) {
+        return err;
+    }
+
+    server_limit = atoi(arg);
+    return NULL;
+}
+
+static const char *set_thread_limit(cmd_parms * cmd, void *dummy,
+                                    const char *arg)
+{
+    const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
+    if (err != NULL) {
+        return err;
+    }
+
+    thread_limit = atoi(arg);
+    return NULL;
+}
+
+static const char *set_worker_factor(cmd_parms * cmd, void *dummy,
+                                     const char *arg)
+{
+    double val;
+    char *endptr;
+    const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
+    if (err != NULL) {
+        return err;
+    }
+
+    val = strtod(arg, &endptr);
+    if (*endptr)
+        return "error parsing value";
+
+    if (val <= 0)
+        return "AsyncRequestWorkerFactor argument must be a positive number";
+
+    worker_factor = val * WORKER_FACTOR_SCALE;
+    if (worker_factor < WORKER_FACTOR_SCALE) {
+        worker_factor = WORKER_FACTOR_SCALE;
+    }
+    return NULL;
+}
+
+
+static const command_rec event_cmds[] = {
+    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_workers, NULL, RSRC_CONF,
+                  "Deprecated name of MaxRequestWorkers"),
+    AP_INIT_TAKE1("MaxRequestWorkers", set_max_workers, 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_INIT_TAKE1("AsyncRequestWorkerFactor", set_worker_factor, NULL, RSRC_CONF,
+                  "How many additional connects will be accepted per idle "
+                  "worker thread"),
+    AP_GRACEFUL_SHUTDOWN_TIMEOUT_COMMAND,
+    {NULL}
+};
+
+AP_DECLARE_MODULE(mpm_event) = {
+    MPM20_MODULE_STUFF,
+    NULL,                       /* 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/event/mpm_default.h b/server/mpm/event/mpm_default.h
new file mode 100644
index 0000000..214caa0
--- /dev/null
+++ b/server/mpm/event/mpm_default.h
@@ -0,0 +1,56 @@
+/* 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
+ *
+ * @defgroup APACHE_MPM_EVENT Event MPM
+ * @ingroup APACHE_INTERNAL
+ * @{
+ */
+
+#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
+
+#endif /* AP_MPM_DEFAULT_H */
+/** @} */