Adding upstream version 2.4.38.upstream/2.4.38upstream

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

1 files changed, 2406 insertions, 0 deletions

diff --git a/server/mpm/worker/worker.c b/server/mpm/worker/worker.c
new file mode 100644
index 0000000..8012fe2
--- /dev/null
+++ b/server/mpm/worker/worker.c
@@ -0,0 +1,2406 @@
+/* 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.
+ */
+
+/* The purpose of this MPM is to fix the design flaws in the threaded
+ * model.  Because of the way that pthreads and mutex locks interact,
+ * it is basically impossible to cleanly gracefully shutdown a child
+ * process if multiple threads are all blocked in accept.  This model
+ * fixes those problems.
+ */
+
+#include "apr.h"
+#include "apr_portable.h"
+#include "apr_strings.h"
+#include "apr_file_io.h"
+#include "apr_thread_proc.h"
+#include "apr_signal.h"
+#include "apr_thread_mutex.h"
+#include "apr_proc_mutex.h"
+#include "apr_poll.h"
+
+#include <stdlib.h>
+
+#define APR_WANT_STRFUNC
+#include "apr_want.h"
+
+#if APR_HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+#if APR_HAVE_SYS_SOCKET_H
+#include <sys/socket.h>
+#endif
+#if APR_HAVE_SYS_WAIT_H
+#include <sys/wait.h>
+#endif
+#ifdef HAVE_SYS_PROCESSOR_H
+#include <sys/processor.h> /* for bindprocessor() */
+#endif
+
+#if !APR_HAS_THREADS
+#error The Worker 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 "ap_mpm.h"
+#include "mpm_common.h"
+#include "ap_listen.h"
+#include "scoreboard.h"
+#include "mpm_fdqueue.h"
+#include "mpm_default.h"
+#include "util_mutex.h"
+#include "unixd.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  * server_limit 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 20000
+#endif
+
+/*
+ * Actual definitions of config globals
+ */
+
+static int threads_per_child = 0;     /* Worker threads per child */
+static int ap_daemons_to_start = 0;
+static int min_spare_threads = 0;
+static int max_spare_threads = 0;
+static int ap_daemons_limit = 0;
+static int max_workers = 0;
+static int server_limit = 0;
+static int thread_limit = 0;
+static int had_healthy_child = 0;
+static int dying = 0;
+static int workers_may_exit = 0;
+static int start_thread_may_exit = 0;
+static int listener_may_exit = 0;
+static int requests_this_child;
+static int num_listensocks = 0;
+static int resource_shortage = 0;
+static fd_queue_t *worker_queue;
+static fd_queue_info_t *worker_queue_info;
+static apr_pollset_t *worker_pollset;
+
+
+/* data retained by worker across load/unload of the module
+ * allocated on first call to pre-config hook; located on
+ * subsequent calls to pre-config hook
+ */
+typedef struct worker_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_daemons_limit;
+    /*
+     * 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;
+} worker_retained_data;
+static worker_retained_data *retained;
+
+typedef struct worker_child_bucket {
+    ap_pod_t *pod;
+    ap_listen_rec *listeners;
+    apr_proc_mutex_t *mutex;
+} worker_child_bucket;
+static worker_child_bucket *all_buckets, /* All listeners buckets */
+                           *my_bucket;   /* Current child bucket */
+
+#define MPM_CHILD_PID(i) (ap_scoreboard_image->parent[i].pid)
+
+/* The structure used to pass unique initialization info to each thread */
+typedef struct {
+    int pid;
+    int tid;
+    int sd;
+} proc_info;
+
+/* Structure used to pass information to the thread responsible for
+ * creating the rest of the threads.
+ */
+typedef struct {
+    apr_thread_t **threads;
+    apr_thread_t *listener;
+    int child_num_arg;
+    apr_threadattr_t *threadattr;
+} thread_starter;
+
+#define ID_FROM_CHILD_THREAD(c, t)    ((c * thread_limit) + t)
+
+/* The worker MPM respects a couple of runtime flags that can aid
+ * in debugging. Setting the -DNO_DETACH flag will prevent the root process
+ * from detaching from its controlling terminal. Additionally, setting
+ * the -DONE_PROCESS flag (which implies -DNO_DETACH) will get you the
+ * child_main loop running in the process which originally started up.
+ * This gives you a pretty nice debugging environment.  (You'll get a SIGHUP
+ * early in standalone_main; just continue through.  This is the server
+ * trying to kill off any child processes which it might have lying
+ * around --- Apache doesn't keep track of their pids, it just sends
+ * SIGHUP to the process group, ignoring it in the root process.
+ * Continue through and you'll be fine.).
+ */
+
+static int one_process = 0;
+
+#ifdef DEBUG_SIGSTOP
+int raise_sigstop_flags;
+#endif
+
+static apr_pool_t *pconf;                 /* Pool for config stuff */
+static apr_pool_t *pchild;                /* Pool for httpd child stuff */
+static 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;
+
+#ifdef SINGLE_LISTEN_UNSERIALIZED_ACCEPT
+#define SAFE_ACCEPT(stmt) (ap_listeners->next ? (stmt) : APR_SUCCESS)
+#else
+#define SAFE_ACCEPT(stmt) (stmt)
+#endif
+
+/* 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
+
+/* The WORKER_SIGNAL signal will be sent from the main thread to the
+ * worker threads during an ungraceful restart or shutdown.
+ * This ensures that on systems (i.e., Linux) where closing the worker
+ * socket doesn't awake the worker thread when it is polling on the socket
+ * (especially in apr_wait_for_io_or_timeout() when handling
+ * Keep-Alive connections), close_worker_sockets() and join_workers()
+ * still function in timely manner and allow ungraceful shutdowns to
+ * proceed to completion.  Otherwise join_workers() doesn't return
+ * before the main process decides the child process is non-responsive
+ * and sends a SIGKILL.
+ */
+#define WORKER_SIGNAL       AP_SIG_GRACEFUL
+
+/* An array of socket descriptors in use by each thread used to
+ * perform a non-graceful (forced) shutdown of the server. */
+static apr_socket_t **worker_sockets;
+
+static void close_worker_sockets(void)
+{
+    int i;
+    for (i = 0; i < threads_per_child; i++) {
+        if (worker_sockets[i]) {
+            apr_socket_close(worker_sockets[i]);
+            worker_sockets[i] = NULL;
+        }
+    }
+}
+
+static void wakeup_listener(void)
+{
+    listener_may_exit = 1;
+    if (!listener_os_thread) {
+        /* XXX there is an obscure path that this doesn't handle perfectly:
+         *     right after listener thread is created but before
+         *     listener_os_thread is set, the first worker thread hits an
+         *     error and starts graceful termination
+         */
+        return;
+    }
+
+    /* unblock the listener if it's waiting for a worker */
+    ap_queue_info_term(worker_queue_info);
+
+    /*
+     * 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 */
+    }
+}
+
+static int worker_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_daemons_limit;
+            break;
+        case AP_MPMQ_IS_THREADED:
+            *result = AP_MPMQ_STATIC;
+            break;
+        case AP_MPMQ_IS_FORKED:
+            *result = AP_MPMQ_DYNAMIC;
+            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 = ap_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 worker_note_child_killed(int childnum, pid_t pid, ap_generation_t gen)
+{
+    if (childnum != -1) { /* child had a scoreboard slot? */
+        ap_run_child_status(ap_server_conf,
+                            ap_scoreboard_image->parent[childnum].pid,
+                            ap_scoreboard_image->parent[childnum].generation,
+                            childnum, MPM_CHILD_EXITED);
+        ap_scoreboard_image->parent[childnum].pid = 0;
+    }
+    else {
+        ap_run_child_status(ap_server_conf, pid, gen, -1, MPM_CHILD_EXITED);
+    }
+}
+
+static void worker_note_child_started(int slot, pid_t pid)
+{
+    ap_generation_t gen = retained->mpm->my_generation;
+    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);
+}
+
+static void worker_note_child_lost_slot(int slot, pid_t newpid)
+{
+    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf, APLOGNO(00263)
+                 "pid %" APR_PID_T_FMT " taking over scoreboard slot from "
+                 "%" APR_PID_T_FMT "%s",
+                 newpid,
+                 ap_scoreboard_image->parent[slot].pid,
+                 ap_scoreboard_image->parent[slot].quiescing ?
+                 " (quiescing)" : "");
+    ap_run_child_status(ap_server_conf,
+                        ap_scoreboard_image->parent[slot].pid,
+                        ap_scoreboard_image->parent[slot].generation,
+                        slot, MPM_CHILD_LOST_SLOT);
+    /* Don't forget about this exiting child process, or we
+     * won't be able to kill it if it doesn't exit by the
+     * time the server is shut down.
+     */
+    ap_register_extra_mpm_process(ap_scoreboard_image->parent[slot].pid,
+                                  ap_scoreboard_image->parent[slot].generation);
+}
+
+static const char *worker_get_name(void)
+{
+    return "worker";
+}
+
+/* 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 (pchild) {
+        apr_pool_destroy(pchild);
+    }
+
+    if (one_process) {
+        worker_note_child_killed(/* slot */ 0, 0, 0);
+    }
+
+    exit(code);
+}
+
+static void just_die(int sig)
+{
+    clean_child_exit(0);
+}
+
+/*****************************************************************
+ * Connection structures and accounting...
+ */
+
+static int child_fatal;
+
+/*****************************************************************
+ * Here follows a long bunch of generic server bookkeeping stuff...
+ */
+
+/*****************************************************************
+ * Child process main loop.
+ */
+
+static void process_socket(apr_thread_t *thd, apr_pool_t *p, apr_socket_t *sock,
+                           int my_child_num,
+                           int my_thread_num, apr_bucket_alloc_t *bucket_alloc)
+{
+    conn_rec *current_conn;
+    long conn_id = ID_FROM_CHILD_THREAD(my_child_num, my_thread_num);
+    ap_sb_handle_t *sbh;
+
+    ap_create_sb_handle(&sbh, p, my_child_num, my_thread_num);
+
+    current_conn = ap_run_create_connection(p, ap_server_conf, sock,
+                                            conn_id, sbh, bucket_alloc);
+    if (current_conn) {
+        current_conn->current_thread = thd;
+        ap_process_connection(current_conn, sock);
+        ap_lingering_close(current_conn);
+    }
+}
+
+/* requests_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) {
+        signal_threads(ST_GRACEFUL);
+    }
+    else {
+        requests_this_child = INT_MAX;      /* keep going */
+    }
+}
+
+static void unblock_signal(int sig)
+{
+    sigset_t sig_mask;
+
+    sigemptyset(&sig_mask);
+    sigaddset(&sig_mask, sig);
+#if defined(SIGPROCMASK_SETS_THREAD_MASK)
+    sigprocmask(SIG_UNBLOCK, &sig_mask, NULL);
+#else
+    pthread_sigmask(SIG_UNBLOCK, &sig_mask, NULL);
+#endif
+}
+
+static void dummy_signal_handler(int sig)
+{
+    /* XXX If specifying SIG_IGN is guaranteed to unblock a syscall,
+     *     then we don't need this goofy function.
+     */
+}
+
+static void accept_mutex_error(const char *func, apr_status_t rv, int process_slot)
+{
+    int level = APLOG_EMERG;
+
+    if (ap_scoreboard_image->parent[process_slot].generation !=
+        ap_scoreboard_image->global->running_generation) {
+        level = APLOG_DEBUG; /* common to get these at restart time */
+    }
+    else if (requests_this_child == INT_MAX
+        || ((requests_this_child == ap_max_requests_per_child)
+            && ap_max_requests_per_child)) {
+        ap_log_error(APLOG_MARK, level, rv, ap_server_conf, APLOGNO(00272)
+                     "apr_proc_mutex_%s failed "
+                     "before this child process served any requests.",
+                     func);
+        clean_child_exit(APEXIT_CHILDSICK);
+    }
+    ap_log_error(APLOG_MARK, level, rv, ap_server_conf, APLOGNO(00273)
+                 "apr_proc_mutex_%s failed. Attempting to "
+                 "shutdown process gracefully.", func);
+    signal_threads(ST_GRACEFUL);
+}
+
+static void * APR_THREAD_FUNC listener_thread(apr_thread_t *thd, void * dummy)
+{
+    proc_info * ti = dummy;
+    int process_slot = ti->pid;
+    void *csd = NULL;
+    apr_pool_t *ptrans = NULL;            /* Pool for per-transaction stuff */
+    apr_status_t rv;
+    ap_listen_rec *lr = NULL;
+    int have_idle_worker = 0;
+    int last_poll_idx = 0;
+
+    free(ti);
+
+    /* Unblock the signal used to wake this thread up, and set a handler for
+     * it.
+     */
+    unblock_signal(LISTENER_SIGNAL);
+    apr_signal(LISTENER_SIGNAL, dummy_signal_handler);
+
+    /* TODO: Switch to a system where threads reuse the results from earlier
+       poll calls - manoj */
+    while (1) {
+        /* TODO: requests_this_child should be synchronized - aaron */
+        if (requests_this_child <= 0) {
+            check_infinite_requests();
+        }
+        if (listener_may_exit) break;
+
+        if (!have_idle_worker) {
+            rv = ap_queue_info_wait_for_idler(worker_queue_info, NULL);
+            if (APR_STATUS_IS_EOF(rv)) {
+                break; /* we've been signaled to die now */
+            }
+            else if (rv != APR_SUCCESS) {
+                ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf,
+                             "apr_queue_info_wait failed. Attempting to "
+                             " shutdown process gracefully.");
+                signal_threads(ST_GRACEFUL);
+                break;
+            }
+            have_idle_worker = 1;
+        }
+
+        /* We've already decremented the idle worker count inside
+         * ap_queue_info_wait_for_idler. */
+
+        if ((rv = SAFE_ACCEPT(apr_proc_mutex_lock(my_bucket->mutex)))
+            != APR_SUCCESS) {
+
+            if (!listener_may_exit) {
+                accept_mutex_error("lock", rv, process_slot);
+            }
+            break;                    /* skip the lock release */
+        }
+
+        if (!my_bucket->listeners->next) {
+            /* Only one listener, so skip the poll */
+            lr = my_bucket->listeners;
+        }
+        else {
+            while (!listener_may_exit) {
+                apr_int32_t numdesc;
+                const apr_pollfd_t *pdesc;
+
+                rv = apr_pollset_poll(worker_pollset, -1, &numdesc, &pdesc);
+                if (rv != APR_SUCCESS) {
+                    if (APR_STATUS_IS_EINTR(rv)) {
+                        continue;
+                    }
+
+                    /* apr_pollset_poll() will only return errors in catastrophic
+                     * circumstances. Let's try exiting gracefully, for now. */
+                    ap_log_error(APLOG_MARK, APLOG_ERR, rv, ap_server_conf, APLOGNO(03137)
+                                 "apr_pollset_poll: (listen)");
+                    signal_threads(ST_GRACEFUL);
+                }
+
+                if (listener_may_exit) break;
+
+                /* We can always use pdesc[0], but sockets at position N
+                 * could end up completely starved of attention in a very
+                 * busy server. Therefore, we round-robin across the
+                 * returned set of descriptors. While it is possible that
+                 * the returned set of descriptors might flip around and
+                 * continue to starve some sockets, we happen to know the
+                 * internal pollset implementation retains ordering
+                 * stability of the sockets. Thus, the round-robin should
+                 * ensure that a socket will eventually be serviced.
+                 */
+                if (last_poll_idx >= numdesc)
+                    last_poll_idx = 0;
+
+                /* Grab a listener record from the client_data of the poll
+                 * descriptor, and advance our saved index to round-robin
+                 * the next fetch.
+                 *
+                 * ### hmm... this descriptor might have POLLERR rather
+                 * ### than POLLIN
+                 */
+                lr = pdesc[last_poll_idx++].client_data;
+                break;
+
+            } /* while */
+
+        } /* if/else */
+
+        if (!listener_may_exit) {
+            /* the following pops a recycled ptrans pool off a stack */
+            ap_queue_info_pop_pool(worker_queue_info, &ptrans);
+            if (ptrans == NULL) {
+                /* we can't use a recycled transaction pool this time.
+                 * create a new transaction pool */
+                apr_allocator_t *allocator;
+
+                apr_allocator_create(&allocator);
+                apr_allocator_max_free_set(allocator, ap_max_mem_free);
+                apr_pool_create_ex(&ptrans, pconf, NULL, allocator);
+                apr_allocator_owner_set(allocator, ptrans);
+                apr_pool_tag(ptrans, "transaction");
+            }
+            rv = lr->accept_func(&csd, lr, ptrans);
+            /* later we trash rv and rely on csd to indicate success/failure */
+            AP_DEBUG_ASSERT(rv == APR_SUCCESS || !csd);
+
+            if (rv == APR_EGENERAL) {
+                /* E[NM]FILE, ENOMEM, etc */
+                resource_shortage = 1;
+                signal_threads(ST_GRACEFUL);
+            }
+            if ((rv = SAFE_ACCEPT(apr_proc_mutex_unlock(my_bucket->mutex)))
+                != APR_SUCCESS) {
+
+                if (listener_may_exit) {
+                    break;
+                }
+                accept_mutex_error("unlock", rv, process_slot);
+            }
+            if (csd != NULL) {
+                rv = ap_queue_push_socket(worker_queue, csd, NULL, ptrans);
+                if (rv) {
+                    /* trash the connection; we couldn't queue the connected
+                     * socket to a worker
+                     */
+                    apr_socket_close(csd);
+                    ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ap_server_conf, APLOGNO(03138)
+                                 "ap_queue_push_socket failed");
+                }
+                else {
+                    have_idle_worker = 0;
+                }
+            }
+        }
+        else {
+            if ((rv = SAFE_ACCEPT(apr_proc_mutex_unlock(my_bucket->mutex)))
+                != APR_SUCCESS) {
+                int level = APLOG_EMERG;
+
+                if (ap_scoreboard_image->parent[process_slot].generation !=
+                    ap_scoreboard_image->global->running_generation) {
+                    level = APLOG_DEBUG; /* common to get these at restart time */
+                }
+                ap_log_error(APLOG_MARK, level, rv, ap_server_conf, APLOGNO(00274)
+                             "apr_proc_mutex_unlock failed. Attempting to "
+                             "shutdown process gracefully.");
+                signal_threads(ST_GRACEFUL);
+            }
+            break;
+        }
+    }
+
+    ap_close_listeners_ex(my_bucket->listeners);
+    ap_queue_info_free_idle_pools(worker_queue_info);
+    ap_queue_term(worker_queue);
+    dying = 1;
+    ap_scoreboard_image->parent[process_slot].quiescing = 1;
+
+    /* wake up the main thread */
+    kill(ap_my_pid, SIGTERM);
+
+    apr_thread_exit(thd, APR_SUCCESS);
+    return NULL;
+}
+
+/* XXX For ungraceful termination/restart, we definitely don't want to
+ *     wait for active connections to finish but we may want to wait
+ *     for idle workers to get out of the queue code and release mutexes,
+ *     since those mutexes are cleaned up pretty soon and some systems
+ *     may not react favorably (i.e., segfault) if operations are attempted
+ *     on cleaned-up mutexes.
+ */
+static void * APR_THREAD_FUNC worker_thread(apr_thread_t *thd, void * dummy)
+{
+    proc_info * ti = dummy;
+    int process_slot = ti->pid;
+    int thread_slot = ti->tid;
+    apr_socket_t *csd = NULL;
+    apr_bucket_alloc_t *bucket_alloc;
+    apr_pool_t *last_ptrans = NULL;
+    apr_pool_t *ptrans;                /* Pool for per-transaction stuff */
+    apr_status_t rv;
+    int is_idle = 0;
+
+    free(ti);
+
+    ap_scoreboard_image->servers[process_slot][thread_slot].pid = ap_my_pid;
+    ap_scoreboard_image->servers[process_slot][thread_slot].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);
+
+#ifdef HAVE_PTHREAD_KILL
+    unblock_signal(WORKER_SIGNAL);
+    apr_signal(WORKER_SIGNAL, dummy_signal_handler);
+#endif
+
+    while (!workers_may_exit) {
+        if (!is_idle) {
+            rv = ap_queue_info_set_idle(worker_queue_info, last_ptrans);
+            last_ptrans = NULL;
+            if (rv != APR_SUCCESS) {
+                ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf,
+                             "ap_queue_info_set_idle failed. Attempting to "
+                             "shutdown process gracefully.");
+                signal_threads(ST_GRACEFUL);
+                break;
+            }
+            is_idle = 1;
+        }
+
+        ap_update_child_status_from_indexes(process_slot, thread_slot,
+                                            SERVER_READY, NULL);
+worker_pop:
+        if (workers_may_exit) {
+            break;
+        }
+        rv = ap_queue_pop_socket(worker_queue, &csd, &ptrans);
+
+        if (rv != APR_SUCCESS) {
+            /* We get APR_EOF during a graceful shutdown once all the connections
+             * accepted by this server process have been handled.
+             */
+            if (APR_STATUS_IS_EOF(rv)) {
+                break;
+            }
+            /* We get APR_EINTR whenever ap_queue_pop_*() has been interrupted
+             * from an explicit call to ap_queue_interrupt_all(). This allows
+             * us to unblock threads stuck in ap_queue_pop_*() when a shutdown
+             * is pending.
+             *
+             * If workers_may_exit is set and this is ungraceful termination/
+             * restart, we are bound to get an error on some systems (e.g.,
+             * AIX, which sanity-checks mutex operations) since the queue
+             * may have already been cleaned up.  Don't log the "error" if
+             * workers_may_exit is set.
+             */
+            else if (APR_STATUS_IS_EINTR(rv)) {
+                goto worker_pop;
+            }
+            /* We got some other error. */
+            else if (!workers_may_exit) {
+                ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ap_server_conf, APLOGNO(03139)
+                             "ap_queue_pop_socket failed");
+            }
+            continue;
+        }
+        is_idle = 0;
+        worker_sockets[thread_slot] = csd;
+        bucket_alloc = apr_bucket_alloc_create(ptrans);
+        process_socket(thd, ptrans, csd, process_slot, thread_slot, bucket_alloc);
+        worker_sockets[thread_slot] = NULL;
+        requests_this_child--;
+        apr_pool_clear(ptrans);
+        last_ptrans = ptrans;
+    }
+
+    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->pid = my_child_num;
+    my_info->tid = -1; /* listener thread doesn't have a thread slot */
+    my_info->sd = 0;
+    rv = apr_thread_create(&ts->listener, thread_attr, listener_thread,
+                           my_info, pruntime);
+    if (rv != APR_SUCCESS) {
+        ap_log_error(APLOG_MARK, APLOG_ALERT, rv, ap_server_conf, APLOGNO(00275)
+                     "apr_thread_create: unable to create listener thread");
+        /* let the parent decide how bad this really is */
+        clean_child_exit(APEXIT_CHILDSICK);
+    }
+    apr_os_thread_get(&listener_os_thread, ts->listener);
+}
+
+static void setup_threads_runtime(void)
+{
+    ap_listen_rec *lr;
+    apr_status_t rv;
+
+    /* 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 explicitely
+     * 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(03140)
+                     "ap_queue_create() failed");
+        clean_child_exit(APEXIT_CHILDFATAL);
+    }
+
+    rv = ap_queue_info_create(&worker_queue_info, pruntime,
+                              threads_per_child, -1);
+    if (rv != APR_SUCCESS) {
+        ap_log_error(APLOG_MARK, APLOG_ALERT, rv, ap_server_conf, APLOGNO(03141)
+                     "ap_queue_info_create() failed");
+        clean_child_exit(APEXIT_CHILDFATAL);
+    }
+
+    /* Create the main pollset */
+    rv = apr_pollset_create(&worker_pollset, num_listensocks, pruntime,
+                            APR_POLLSET_NOCOPY);
+    if (rv != APR_SUCCESS) {
+        ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf, APLOGNO(03285)
+                     "Couldn't create pollset in thread;"
+                     " check system or user limits");
+        /* let the parent decide how bad this really is */
+        clean_child_exit(APEXIT_CHILDSICK);
+    }
+
+    for (lr = my_bucket->listeners; lr != NULL; lr = lr->next) {
+        apr_pollfd_t *pfd = apr_pcalloc(pruntime, sizeof *pfd);
+
+        pfd->desc_type = APR_POLL_SOCKET;
+        pfd->desc.s = lr->sd;
+        pfd->reqevents = APR_POLLIN;
+        pfd->client_data = lr;
+
+        rv = apr_pollset_add(worker_pollset, pfd);
+        if (rv != APR_SUCCESS) {
+            ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf, APLOGNO(03286)
+                         "Couldn't create add listener to pollset;"
+                         " check system or user limits");
+            /* let the parent decide how bad this really is */
+            clean_child_exit(APEXIT_CHILDSICK);
+        }
+
+        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;
+
+    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_GRACEFUL && status != SERVER_DEAD) {
+                continue;
+            }
+
+            my_info = (proc_info *)ap_malloc(sizeof(proc_info));
+            my_info->pid = my_child_num;
+            my_info->tid = i;
+            my_info->sd = 0;
+
+            /* We are creating threads right now */
+            ap_update_child_status_from_indexes(my_child_num, i,
+                                                SERVER_STARTING, NULL);
+            /* We let each thread update its own scoreboard entry.  This is
+             * done because it lets us deal with tid better.
+             */
+            rv = apr_thread_create(&threads[i], thread_attr,
+                                   worker_thread, my_info, pruntime);
+            if (rv != APR_SUCCESS) {
+                ap_log_error(APLOG_MARK, APLOG_ALERT, rv, ap_server_conf, APLOGNO(03142)
+                             "apr_thread_create: unable to create worker thread");
+                /* let the parent decide how bad this really is */
+                clean_child_exit(APEXIT_CHILDSICK);
+            }
+            threads_created++;
+        }
+        /* Start the listener only when there are workers available */
+        if (!listener_started && threads_created) {
+            create_listener_thread(ts);
+            listener_started = 1;
+        }
+        if (start_thread_may_exit || threads_created == 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 mode)
+{
+    int i;
+    apr_status_t rv, thread_rv;
+
+    if (listener) {
+        int iter;
+
+        /* deal with a rare timing window which affects waking up the
+         * listener thread...  if the signal sent to the listener thread
+         * is delivered between the time it verifies that the
+         * listener_may_exit flag is clear and the time it enters a
+         * blocking syscall, the signal didn't do any good...  work around
+         * that by sleeping briefly and sending it again
+         */
+
+        iter = 0;
+        while (iter < 10 &&
+#ifdef HAVE_PTHREAD_KILL
+               pthread_kill(*listener_os_thread, 0)
+#else
+               kill(ap_my_pid, 0)
+#endif
+               == 0) {
+            /* listener not dead yet */
+            apr_sleep(apr_time_make(0, 500000));
+            wakeup_listener();
+            ++iter;
+        }
+        if (iter >= 10) {
+            ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf, APLOGNO(00276)
+                         "the listener thread didn't exit");
+        }
+        else {
+            rv = apr_thread_join(&thread_rv, listener);
+            if (rv != APR_SUCCESS) {
+                ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ap_server_conf, APLOGNO(00277)
+                             "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 */
+            if (mode != ST_GRACEFUL) {
+#ifdef HAVE_PTHREAD_KILL
+                apr_os_thread_t *worker_os_thread;
+
+                apr_os_thread_get(&worker_os_thread, threads[i]);
+                pthread_kill(*worker_os_thread, WORKER_SIGNAL);
+#endif
+            }
+
+            rv = apr_thread_join(&thread_rv, threads[i]);
+            if (rv != APR_SUCCESS) {
+                ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ap_server_conf, APLOGNO(00278)
+                             "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(00279)
+                     "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_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");
+
+    /* 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);
+
+    rv = SAFE_ACCEPT(apr_proc_mutex_child_init(&my_bucket->mutex,
+                                    apr_proc_mutex_lockfile(my_bucket->mutex),
+                                    pchild));
+    if (rv != APR_SUCCESS) {
+        ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf, APLOGNO(00280)
+                     "Couldn't initialize cross-process lock in child");
+        clean_child_exit(APEXIT_CHILDFATAL);
+    }
+
+    /* 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" (implicitely) MPM's signals.
+     */
+    rv = apr_setup_signal_thread();
+    if (rv != APR_SUCCESS) {
+        ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf, APLOGNO(00281)
+                     "Couldn't initialize signal thread");
+        clean_child_exit(APEXIT_CHILDFATAL);
+    }
+
+    ap_run_child_init(pchild, ap_server_conf);
+
+    if (ap_max_requests_per_child) {
+        requests_this_child = ap_max_requests_per_child;
+    }
+    else {
+        /* coding a value of zero means infinity */
+        requests_this_child = INT_MAX;
+    }
+
+    /* Setup 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 = (apr_thread_t **)ap_calloc(1,
+                                  sizeof(apr_thread_t *) * threads_per_child);
+    ts = (thread_starter *)apr_palloc(pchild, sizeof(*ts));
+
+    apr_threadattr_create(&thread_attr, pchild);
+    /* 0 means PTHREAD_CREATE_JOINABLE */
+    apr_threadattr_detach_set(thread_attr, 0);
+
+    if (ap_thread_stacksize != 0) {
+        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(02435)
+                         "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 = apr_thread_create(&start_thread_id, thread_attr, start_threads,
+                           ts, pchild);
+    if (rv != APR_SUCCESS) {
+        ap_log_error(APLOG_MARK, APLOG_ALERT, rv, ap_server_conf, APLOGNO(00282)
+                     "apr_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);
+        signal_threads(ST_UNGRACEFUL); /* helps us terminate a little more
+                           * quickly than the dispatch of the signal thread
+                           * beats the Pipe of Death and the browsers
+                           */
+        /* 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, ST_UNGRACEFUL);
+    }
+    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
+         */
+        unblock_signal(SIGTERM);
+        apr_signal(SIGTERM, dummy_signal_handler);
+        /* 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).
+         */
+        join_workers(ts->listener, threads,
+                     rv == AP_MPM_PODX_GRACEFUL ? ST_GRACEFUL : ST_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_daemons_limit) {
+        retained->max_daemons_limit = slot + 1;
+    }
+
+    if (one_process) {
+        my_bucket = &all_buckets[0];
+
+        worker_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(00283)
+                     "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) {
+        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(00284)
+                         "processor unbind failed");
+#endif
+        RAISE_SIGSTOP(MAKE_CHILD);
+
+        apr_signal(SIGTERM, just_die);
+        child_main(slot, bucket);
+        /* NOTREACHED */
+        ap_assert(0);
+        return -1;
+    }
+
+    if (ap_scoreboard_image->parent[slot].pid != 0) {
+        /* This new child process is squatting on the scoreboard
+         * entry owned by an exiting child process, which cannot
+         * exit until all active requests complete.
+         */
+        worker_note_child_lost_slot(slot, pid);
+    }
+    ap_scoreboard_image->parent[slot].quiescing = 0;
+    ap_scoreboard_image->parent[slot].bucket = bucket;
+    worker_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 < ap_daemons_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 num_buckets)
+{
+    int i, j;
+    int idle_thread_count;
+    worker_score *ws;
+    process_score *ps;
+    int free_length;
+    int totally_free_length = 0;
+    int free_slots[MAX_SPAWN_RATE];
+    int last_non_dead;
+    int total_non_dead;
+    int active_thread_count = 0;
+
+    /* initialize the free_list */
+    free_length = 0;
+
+    idle_thread_count = 0;
+    last_non_dead = -1;
+    total_non_dead = 0;
+
+    for (i = 0; i < ap_daemons_limit; ++i) {
+        /* Initialization to satisfy the compiler. It doesn't know
+         * that threads_per_child is always > 0 */
+        int status = SERVER_DEAD;
+        int any_dying_threads = 0;
+        int any_dead_threads = 0;
+        int all_dead_threads = 1;
+        int child_threads_active = 0;
+
+        if (i >= retained->max_daemons_limit &&
+            totally_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];
+        for (j = 0; j < threads_per_child; j++) {
+            ws = &ap_scoreboard_image->servers[i][j];
+            status = ws->status;
+
+            /* XXX any_dying_threads is probably no longer needed    GLA */
+            any_dying_threads = any_dying_threads ||
+                                (status == SERVER_GRACEFUL);
+            any_dead_threads = any_dead_threads || (status == SERVER_DEAD);
+            all_dead_threads = all_dead_threads &&
+                                   (status == SERVER_DEAD ||
+                                    status == SERVER_GRACEFUL);
+
+            /* We consider a starting server as idle because we started it
+             * at least a cycle ago, and if it still hasn't finished starting
+             * then we're just going to swamp things worse by forking more.
+             * So we hopefully won't need to fork more if we count it.
+             * This depends on the ordering of SERVER_READY and SERVER_STARTING.
+             */
+            if (ps->pid != 0) { /* XXX just set all_dead_threads in outer for
+                                   loop if no pid?  not much else matters */
+                if (status <= SERVER_READY &&
+                        !ps->quiescing &&
+                        ps->generation == retained->mpm->my_generation &&
+                        ps->bucket == child_bucket) {
+                    ++idle_thread_count;
+                }
+                if (status >= SERVER_READY && status < SERVER_GRACEFUL) {
+                    ++child_threads_active;
+                }
+            }
+        }
+        active_thread_count += child_threads_active;
+        if (any_dead_threads
+                && totally_free_length < retained->idle_spawn_rate[child_bucket]
+                && free_length < MAX_SPAWN_RATE / num_buckets
+                && (!ps->pid               /* no process in the slot */
+                    || ps->quiescing)) {   /* or at least one is going away */
+            if (all_dead_threads) {
+                /* great! we prefer these, because the new process can
+                 * start more threads sooner.  So prioritize this slot
+                 * by putting it ahead of any slots with active threads.
+                 *
+                 * first, make room by moving a slot that's potentially still
+                 * in use to the end of the array
+                 */
+                free_slots[free_length] = free_slots[totally_free_length];
+                free_slots[totally_free_length++] = i;
+            }
+            else {
+                /* slot is still in use - back of the bus
+                 */
+                free_slots[free_length] = i;
+            }
+            ++free_length;
+        }
+        else if (child_threads_active == threads_per_child) {
+            had_healthy_child = 1;
+        }
+        /* XXX if (!ps->quiescing)     is probably more reliable  GLA */
+        if (!any_dying_threads) {
+            last_non_dead = i;
+            ++total_non_dead;
+        }
+    }
+
+    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 {
+            /* 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(02325)
+                         "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;
+        }
+    }
+
+    retained->max_daemons_limit = last_non_dead + 1;
+
+    if (idle_thread_count > max_spare_threads / num_buckets) {
+        /* Kill off one child */
+        ap_mpm_podx_signal(all_buckets[child_bucket].pod,
+                           AP_MPM_PODX_GRACEFUL);
+        retained->idle_spawn_rate[child_bucket] = 1;
+    }
+    else if (idle_thread_count < min_spare_threads / num_buckets) {
+        /* terminate the free list */
+        if (free_length == 0) { /* scoreboard is full, can't fork */
+
+            if (active_thread_count >= ap_daemons_limit * threads_per_child) {
+                /* no threads are "inactive" - starting, stopping, etc. */
+                /* have we reached MaxRequestWorkers, or just getting close? */
+                if (0 == idle_thread_count) {
+                    if (!retained->maxclients_reported) {
+                        /* only report this condition once */
+                        ap_log_error(APLOG_MARK, APLOG_ERR, 0, ap_server_conf, APLOGNO(00286)
+                                     "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(00287)
+                                     "server is within MinSpareThreads of "
+                                     "MaxRequestWorkers, consider raising the "
+                                     "MaxRequestWorkers setting");
+                        retained->near_maxclients_reported = 1;
+                    }
+                }
+            }
+            else {
+                ap_log_error(APLOG_MARK, APLOG_ERR, 0,
+                             ap_server_conf, APLOGNO(00288)
+                             "scoreboard is full, not at MaxRequestWorkers");
+            }
+            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 (retained->idle_spawn_rate[child_bucket] >= 8) {
+                ap_log_error(APLOG_MARK, APLOG_INFO, 0,
+                             ap_server_conf, APLOGNO(00289)
+                             "server seems busy, (you may need "
+                             "to increase StartServers, ThreadsPerChild "
+                             "or Min/MaxSpareThreads), "
+                             "spawning %d children, there are around %d idle "
+                             "threads, and %d total children", free_length,
+                             idle_thread_count, total_non_dead);
+            }
+            for (i = 0; i < free_length; ++i) {
+                make_child(ap_server_conf, free_slots[i], child_bucket);
+            }
+            /* 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)
+{
+    ap_generation_t old_gen;
+    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;
+                    return;
+                }
+                else {
+                    ap_log_error(APLOG_MARK, APLOG_WARNING, 0, ap_server_conf, APLOGNO(00290)
+                                 "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) {
+                process_score *ps;
+
+                for (i = 0; i < threads_per_child; i++)
+                    ap_update_child_status_from_indexes(child_slot, i,
+                                                        SERVER_DEAD, NULL);
+
+                worker_note_child_killed(child_slot, 0, 0);
+                ps = &ap_scoreboard_image->parent[child_slot];
+                ps->quiescing = 0;
+                if (processed_status == APEXIT_CHILDSICK) {
+                    /* resource shortage, minimize the fork rate */
+                    retained->idle_spawn_rate[ps->bucket] = 1;
+                }
+                else if (remaining_children_to_start
+                    && child_slot < ap_daemons_limit) {
+                    /* we're still doing a 1-for-1 replacement of dead
+                     * children with new children
+                     */
+                    make_child(ap_server_conf, child_slot, ps->bucket);
+                    --remaining_children_to_start;
+                }
+            }
+            else if (ap_unregister_extra_mpm_process(pid.pid, &old_gen) == 1) {
+                worker_note_child_killed(-1, /* already out of the scoreboard */
+                                         pid.pid, old_gen);
+                if (processed_status == APEXIT_CHILDSICK
+                    && old_gen == retained->mpm->my_generation) {
+                    /* resource shortage, minimize the fork rate */
+                    for (i = 0; i < num_buckets; i++) {
+                        retained->idle_spawn_rate[i] = 1;
+                    }
+                }
+#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(00291)
+                             "long lost child came home! (pid %ld)",
+                             (long)pid.pid);
+            }
+            /* Don't perform idle maintenance when a child dies,
+             * only do it when there's a timeout.  Remember only a
+             * finite number of children can die, and it's pretty
+             * pathological for a lot to die suddenly.
+             */
+            continue;
+        }
+        else if (remaining_children_to_start) {
+            /* we hit a 1 second timeout in which none of the previous
+             * generation of children needed to be reaped... so assume
+             * they're all done, and pick up the slack if any is left.
+             */
+            startup_children(remaining_children_to_start);
+            remaining_children_to_start = 0;
+            /* In any event we really shouldn't do the code below because
+             * few of the servers we just started are in the IDLE state
+             * yet, so we'd mistakenly create an extra server.
+             */
+            continue;
+        }
+
+        for (i = 0; i < num_buckets; i++) {
+            perform_idle_server_maintenance(i, num_buckets);
+        }
+    }
+}
+
+static int worker_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 (ap_daemons_limit < num_buckets)
+        ap_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 > ap_daemons_limit) {
+        remaining_children_to_start = ap_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(00292)
+                "%s configured -- resuming normal operations",
+                ap_get_server_description());
+    ap_log_error(APLOG_MARK, APLOG_INFO, 0, ap_server_conf, APLOGNO(00293)
+                "Server built: %s", ap_get_server_built());
+    ap_log_command_line(plog, s);
+    ap_log_mpm_common(s);
+    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf, APLOGNO(00294)
+                "Accept mutex: %s (default: %s)",
+                (all_buckets[0].mutex)
+                    ? apr_proc_mutex_name(all_buckets[0].mutex)
+                    : "none",
+                apr_proc_mutex_defname());
+    retained->mpm->mpm_state = AP_MPMQ_RUNNING;
+
+    server_main_loop(remaining_children_to_start, num_buckets);
+    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, ap_daemons_limit,
+                               AP_MPM_PODX_RESTART);
+        }
+        ap_reclaim_child_processes(1, /* Start with SIGTERM */
+                                   worker_note_child_killed);
+
+        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(00295) "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, ap_daemons_limit,
+                               AP_MPM_PODX_GRACEFUL);
+        }
+        ap_relieve_child_processes(worker_note_child_killed);
+
+        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(00296)
+                         "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(worker_note_child_killed);
+
+            active_children = 0;
+            for (index = 0; index < ap_daemons_limit; ++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, ap_daemons_limit,
+                               AP_MPM_PODX_RESTART);
+        }
+        ap_reclaim_child_processes(1, worker_note_child_killed);
+
+        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(00297)
+                     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, ap_daemons_limit,
+                               AP_MPM_PODX_GRACEFUL);
+        }
+
+        /* This is mostly for debugging... so that we know what is still
+         * gracefully dealing with existing request.
+         */
+
+    }
+    else {
+        /* Kill 'em all.  Since the child acts the same on the parents SIGTERM
+         * and a SIGHUP, we may as well use the same signal, because some user
+         * pthreads are stealing signals from us left and right.
+         */
+        for (i = 0; i < num_buckets; i++) {
+            ap_mpm_podx_killpg(all_buckets[i].pod, ap_daemons_limit,
+                               AP_MPM_PODX_RESTART);
+        }
+
+        ap_reclaim_child_processes(1, /* Start with SIGTERM */
+                                   worker_note_child_killed);
+        ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, ap_server_conf, APLOGNO(00298)
+                    "SIGHUP received.  Attempting to restart");
+    }
+
+    return OK;
+}
+
+/* This really should be a post_config hook, but the error log is already
+ * redirected by that point, so we need to do this in the open_logs phase.
+ */
+static int worker_open_logs(apr_pool_t *p, apr_pool_t *plog, apr_pool_t *ptemp, server_rec *s)
+{
+    int startup = 0;
+    int level_flags = 0;
+    int num_buckets = 0;
+    ap_listen_rec **listen_buckets;
+    apr_status_t rv;
+    char id[16];
+    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;
+        }
+        /* Initialize cross-process accept lock (safe accept needed only) */
+        if ((rv = SAFE_ACCEPT((apr_snprintf(id, sizeof id, "%i", i),
+                               ap_proc_mutex_create(&all_buckets[i].mutex,
+                                                    NULL, AP_ACCEPT_MUTEX_TYPE,
+                                                    id, s, pconf, 0))))) {
+            ap_log_error(APLOG_MARK, APLOG_CRIT | level_flags, rv,
+                         (startup ? NULL : s),
+                         "could not create accept mutex");
+            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));
+        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;
+
+    return OK;
+}
+
+static int worker_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_worker_module";
+
+    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");
+    }
+
+    ap_mutex_register(pconf, AP_ACCEPT_MUTEX_TYPE, NULL, APR_LOCK_DEFAULT, 0);
+
+    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();
+        retained->max_daemons_limit = -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;
+
+    /* sigh, want this only the second time around */
+    if (retained->mpm->module_loads == 2) {
+        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(00299)
+                             "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;
+    ap_daemons_limit = server_limit;
+    threads_per_child = DEFAULT_THREADS_PER_CHILD;
+    max_workers = ap_daemons_limit * threads_per_child;
+    had_healthy_child = 0;
+    ap_extended_status = 0;
+
+    return OK;
+}
+
+static int worker_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(00300)
+                         "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(00301)
+                         "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(00302)
+                         "WARNING: ServerLimit of %d not allowed, "
+                         "increasing to 1.", server_limit);
+        } else {
+            ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, APLOGNO(00303)
+                         "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(00304)
+                     "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(00305)
+                         "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(00306)
+                         "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(00307)
+                         "WARNING: ThreadLimit of %d not allowed, "
+                         "increasing to 1.", thread_limit);
+        } else {
+            ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, APLOGNO(00308)
+                         "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(00309)
+                     "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(00310)
+                         "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(00311)
+                         "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(00312)
+                         "WARNING: ThreadsPerChild of %d not allowed, "
+                         "increasing to 1.", threads_per_child);
+        } else {
+            ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, APLOGNO(00313)
+                         "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(00314)
+                         "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(00315)
+                         "MaxRequestWorkers of %d is less than ThreadsPerChild "
+                         "of %d, increasing to match",
+                         max_workers, threads_per_child);
+        }
+        max_workers = threads_per_child;
+    }
+
+    ap_daemons_limit = max_workers / threads_per_child;
+
+    if (max_workers % threads_per_child) {
+        int tmp_max_workers = ap_daemons_limit * threads_per_child;
+
+        if (startup) {
+            ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL, APLOGNO(00316)
+                         "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,
+                         ap_daemons_limit);
+        } else {
+            ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, APLOGNO(00317)
+                         "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 (ap_daemons_limit > server_limit) {
+        if (startup) {
+            ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL, APLOGNO(00318)
+                         "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, ap_daemons_limit, server_limit,
+                         server_limit * threads_per_child);
+        } else {
+            ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, APLOGNO(00319)
+                         "MaxRequestWorkers of %d would require %d servers and "
+                         "exceed ServerLimit of %d, decreasing to %d",
+                         max_workers, ap_daemons_limit, server_limit,
+                         server_limit * threads_per_child);
+        }
+        ap_daemons_limit = server_limit;
+    }
+
+    /* ap_daemons_to_start > ap_daemons_limit checked in worker_run() */
+    if (ap_daemons_to_start < 1) {
+        if (startup) {
+            ap_log_error(APLOG_MARK, APLOG_WARNING | APLOG_STARTUP, 0, NULL, APLOGNO(00320)
+                         "WARNING: StartServers of %d not allowed, "
+                         "increasing to 1.", ap_daemons_to_start);
+        } else {
+            ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s, APLOGNO(00321)
+                         "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(00322)
+                         "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(00323)
+                         "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 worker_run()
+     */
+
+    return OK;
+}
+
+static void worker_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(worker_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(worker_pre_config, NULL, NULL, APR_HOOK_REALLY_FIRST);
+    ap_hook_check_config(worker_check_config, NULL, NULL, APR_HOOK_MIDDLE);
+    ap_hook_mpm(worker_run, NULL, NULL, APR_HOOK_MIDDLE);
+    ap_hook_mpm_query(worker_query, NULL, NULL, APR_HOOK_MIDDLE);
+    ap_hook_mpm_get_name(worker_get_name, NULL, NULL, APR_HOOK_MIDDLE);
+}
+
+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(00324)
+                     "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 command_rec worker_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("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("MaxRequestWorkers", set_max_workers, NULL, RSRC_CONF,
+  "Maximum number of threads alive at the same time"),
+AP_INIT_TAKE1("MaxClients", set_max_workers, NULL, RSRC_CONF,
+  "Deprecated name of MaxRequestWorkers"),
+AP_INIT_TAKE1("ThreadsPerChild", set_threads_per_child, NULL, RSRC_CONF,
+  "Number of threads each child creates"),
+AP_INIT_TAKE1("ServerLimit", set_server_limit, NULL, RSRC_CONF,
+  "Maximum number of child processes for this run of Apache"),
+AP_INIT_TAKE1("ThreadLimit", set_thread_limit, NULL, RSRC_CONF,
+  "Maximum number of worker threads per child process for this run of Apache - Upper limit for ThreadsPerChild"),
+AP_GRACEFUL_SHUTDOWN_TIMEOUT_COMMAND,
+{ NULL }
+};
+
+AP_DECLARE_MODULE(mpm_worker) = {
+    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 */
+    worker_cmds,                /* command apr_table_t */
+    worker_hooks                /* register_hooks */
+};
+