upload http

JIRA: BOTTLENECK-10

Change-Id: I7598427ff904df438ce77c2819ee48ac75ffa8da
Signed-off-by: hongbotian <hongbo.tianhongbo@huawei.com>

6 files changed, 2122 insertions, 0 deletions

diff --git a/rubbos/app/httpd-2.0.64/server/mpm/experimental/leader/Makefile.in b/rubbos/app/httpd-2.0.64/server/mpm/experimental/leader/Makefile.in
new file mode 100644
index 00000000..03f1765e
--- /dev/null
+++ b/rubbos/app/httpd-2.0.64/server/mpm/experimental/leader/Makefile.in
@@ -0,0 +1,5 @@
+
+LTLIBRARY_NAME    = libleader.la
+LTLIBRARY_SOURCES = leader.c
+
+include $(top_srcdir)/build/ltlib.mk
diff --git a/rubbos/app/httpd-2.0.64/server/mpm/experimental/leader/README b/rubbos/app/httpd-2.0.64/server/mpm/experimental/leader/README
new file mode 100644
index 00000000..1981a5be
--- /dev/null
+++ b/rubbos/app/httpd-2.0.64/server/mpm/experimental/leader/README
@@ -0,0 +1,15 @@
+Leader MPM:
+This is an experimental variant of the standard worker MPM.
+It uses a Leader/Followers design pattern to coordinate work among threads:
+http://deuce.doc.wustl.edu/doc/pspdfs/lf.pdf
+
+To use the leader MPM, add "--with-mpm=leader" to the configure
+script's arguments when building the httpd.
+  
+This MPM depends on APR's atomic compare-and-swap operations for
+thread synchronization.  If you are compiling for an x86 target
+and you don't need to support 386s, or you're compiling for a
+SPARC and you don't need to run on pre-UltraSPARC chips, add
+"--enable-nonportable-atomics=yes" to the configure script's
+arguments.  This will cause APR to implement atomic operations
+using efficient opcodes not available in older CPUs.
diff --git a/rubbos/app/httpd-2.0.64/server/mpm/experimental/leader/config5.m4 b/rubbos/app/httpd-2.0.64/server/mpm/experimental/leader/config5.m4
new file mode 100644
index 00000000..9a915abf
--- /dev/null
+++ b/rubbos/app/httpd-2.0.64/server/mpm/experimental/leader/config5.m4
@@ -0,0 +1,6 @@
+dnl ## XXX - Need a more thorough check of the proper flags to use
+
+if test "$MPM_NAME" = "leader" ; then
+    AC_CHECK_FUNCS(pthread_kill)
+    APACHE_FAST_OUTPUT(server/mpm/$MPM_SUBDIR_NAME/Makefile)
+fi
diff --git a/rubbos/app/httpd-2.0.64/server/mpm/experimental/leader/leader.c b/rubbos/app/httpd-2.0.64/server/mpm/experimental/leader/leader.c
new file mode 100644
index 00000000..322c2286
--- /dev/null
+++ b/rubbos/app/httpd-2.0.64/server/mpm/experimental/leader/leader.c
@@ -0,0 +1,1976 @@
+/* Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "apr.h"
+#include "apr_portable.h"
+#include "apr_strings.h"
+#include "apr_file_io.h"
+#include "apr_thread_proc.h"
+#include "apr_signal.h"
+#include "apr_thread_cond.h"
+#include "apr_thread_mutex.h"
+#include "apr_proc_mutex.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 Leader/Follower MPM requires APR threads, but they are unavailable.
+#endif
+
+#define CORE_PRIVATE 
+ 
+#include "ap_config.h"
+#include "httpd.h" 
+#include "http_main.h" 
+#include "http_log.h" 
+#include "http_config.h"        /* for read_config */ 
+#include "http_core.h"          /* for get_remote_host */ 
+#include "http_connection.h"
+#include "ap_mpm.h"
+#include "mpm_common.h"
+#include "ap_listen.h"
+#include "scoreboard.h" 
+#include "mpm_default.h"
+#include "apr_poll.h"
+
+#include <signal.h>
+#include <limits.h>             /* for INT_MAX */
+
+#include "apr_atomic.h"
+
+/* 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
+ */
+
+int ap_threads_per_child = 0;         /* Worker threads per child */
+static int ap_daemons_to_start = 0;
+static int min_spare_threads = 0;
+static int max_spare_threads = 0;
+static int ap_daemons_limit = 0;
+static int server_limit = DEFAULT_SERVER_LIMIT;
+static int first_server_limit;
+static int thread_limit = DEFAULT_THREAD_LIMIT;
+static int first_thread_limit;
+static int changed_limit_at_restart;
+static int dying = 0;
+static int workers_may_exit = 0;
+static int start_thread_may_exit = 0;
+static int requests_this_child;
+static int num_listensocks = 0;
+static int resource_shortage = 0;
+static int mpm_state = AP_MPMQ_STARTING;
+
+typedef struct worker_wakeup_info worker_wakeup_info;
+
+/* 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;
+    int child_num_arg;
+    apr_threadattr_t *threadattr;
+} thread_starter;
+
+#define ID_FROM_CHILD_THREAD(c, t)    ((c * thread_limit) + t)
+
+/*
+ * The max child slot ever assigned, preserved across restarts.  Necessary
+ * to deal with MaxClients changes across AP_SIG_GRACEFUL restarts.  We 
+ * use this value to optimize routines that have to scan the entire 
+ * scoreboard.
+ */
+int ap_max_daemons_limit = -1;
+
+static ap_pod_t *pod;
+
+/* *Non*-shared http_main globals... */
+
+server_rec *ap_server_conf;
+
+/* This MPM respects a couple of runtime flags that can aid in debugging.
+ *  Setting the -DNO_DETACH flag will prevent the root process from
+ *  detaching from its controlling terminal. Additionally, setting
+ * the -DONE_PROCESS flag (which implies -DNO_DETACH) will get you the
+ * child_main loop running in the process which originally started up.
+ * This gives you a pretty nice debugging environment.  (You'll get a SIGHUP
+ * early in standalone_main; just continue through.  This is the server
+ * trying to kill off any child processes which it might have lying
+ * around --- Apache doesn't keep track of their pids, it just sends
+ * SIGHUP to the process group, ignoring it in the root process.
+ * Continue through and you'll be fine.).
+ */
+
+static int one_process = 0;
+
+#ifdef DEBUG_SIGSTOP
+int raise_sigstop_flags;
+#endif
+
+static apr_pool_t *pconf;                 /* Pool for config stuff */
+static apr_pool_t *pchild;                /* Pool for httpd child stuff */
+
+static pid_t ap_my_pid; /* Linux getpid() doesn't work except in main 
+                           thread. Use this instead */
+static pid_t parent_pid;
+
+/* Locks for accept serialization */
+static apr_proc_mutex_t *accept_mutex;
+
+#ifdef SINGLE_LISTEN_UNSERIALIZED_ACCEPT
+#define SAFE_ACCEPT(stmt) (ap_listeners->next ? (stmt) : APR_SUCCESS)
+#else
+#define SAFE_ACCEPT(stmt) (stmt)
+#endif
+
+
+/* Structure used to wake up an idle worker thread
+ */
+struct worker_wakeup_info {
+    apr_uint32_t next; /* index into worker_wakeups array,
+                        * used to build a linked list
+                        */
+    apr_thread_cond_t *cond;
+    apr_thread_mutex_t *mutex;
+};
+
+static worker_wakeup_info *worker_wakeup_create(apr_pool_t *pool)
+{
+    apr_status_t rv;
+    worker_wakeup_info *wakeup;
+
+    wakeup = (worker_wakeup_info *)apr_palloc(pool, sizeof(*wakeup));
+    if ((rv = apr_thread_cond_create(&wakeup->cond, pool)) != APR_SUCCESS) {
+        return NULL;
+    }
+    if ((rv = apr_thread_mutex_create(&wakeup->mutex, APR_THREAD_MUTEX_DEFAULT,
+                                      pool)) != APR_SUCCESS) {
+        return NULL;
+    }
+    /* The wakeup's mutex will be unlocked automatically when
+     * the worker blocks on the condition variable
+     */
+    apr_thread_mutex_lock(wakeup->mutex);
+    return wakeup;
+}
+
+
+/* Structure used to hold a stack of idle worker threads 
+ */
+typedef struct {
+    /* 'state' consists of several fields concatenated into a
+     * single 32-bit int for use with the apr_atomic_cas() API:
+     *   state & STACK_FIRST  is the thread ID of the first thread
+     *                        in a linked list of idle threads
+     *   state & STACK_TERMINATED  indicates whether the proc is shutting down
+     *   state & STACK_NO_LISTENER indicates whether the process has
+     *                             no current listener thread
+     */
+    apr_uint32_t state;
+} worker_stack;
+
+#define STACK_FIRST  0xffff
+#define STACK_LIST_END  0xffff
+#define STACK_TERMINATED 0x10000
+#define STACK_NO_LISTENER 0x20000
+
+static worker_wakeup_info **worker_wakeups = NULL;
+
+static worker_stack* worker_stack_create(apr_pool_t *pool, apr_size_t max)
+{
+    worker_stack *stack = (worker_stack *)apr_palloc(pool, sizeof(*stack));
+    stack->state = STACK_NO_LISTENER | STACK_LIST_END;
+    return stack;
+}
+
+static apr_status_t worker_stack_wait(worker_stack *stack,
+                                      apr_uint32_t worker_id)
+{
+    worker_wakeup_info *wakeup = worker_wakeups[worker_id];
+
+    while (1) {
+        apr_uint32_t state = stack->state;
+        if (state & (STACK_TERMINATED | STACK_NO_LISTENER)) {
+            if (state & STACK_TERMINATED) {
+                return APR_EINVAL;
+            }
+            if (apr_atomic_cas(&(stack->state), STACK_LIST_END, state) !=
+                state) {
+                continue;
+            }
+            else {
+                return APR_SUCCESS;
+            }
+        }
+        wakeup->next = state;
+        if (apr_atomic_cas(&(stack->state), worker_id, state) != state) {
+            continue;
+        }
+        else {
+            return apr_thread_cond_wait(wakeup->cond, wakeup->mutex);
+        }
+    }    
+}
+
+static apr_status_t worker_stack_awaken_next(worker_stack *stack)
+{
+
+    while (1) {
+        apr_uint32_t state = stack->state;
+        apr_uint32_t first = state & STACK_FIRST;
+        if (first == STACK_LIST_END) {
+            if (apr_atomic_cas(&(stack->state), state | STACK_NO_LISTENER,
+                               state) != state) {
+                continue;
+            }
+            else {
+                return APR_SUCCESS;
+            }
+        }
+        else {
+            worker_wakeup_info *wakeup = worker_wakeups[first];
+            if (apr_atomic_cas(&(stack->state), (state ^ first) | wakeup->next,
+                               state) != state) {
+                continue;
+            }
+            else {
+                /* Acquire and release the idle worker's mutex to ensure
+                 * that it's actually waiting on its condition variable
+                 */
+                apr_status_t rv;
+                if ((rv = apr_thread_mutex_lock(wakeup->mutex)) !=
+                    APR_SUCCESS) {
+                    return rv;
+                }
+                if ((rv = apr_thread_mutex_unlock(wakeup->mutex)) !=
+                    APR_SUCCESS) {
+                    return rv;
+                }
+                return apr_thread_cond_signal(wakeup->cond);
+            }
+        }
+    }
+}
+
+static apr_status_t worker_stack_term(worker_stack *stack)
+{
+    int i;
+    apr_status_t rv;
+
+    while (1) {
+        apr_uint32_t state = stack->state;
+        if (apr_atomic_cas(&(stack->state), state | STACK_TERMINATED,
+                           state) == state) {
+            break;
+        }
+    }
+    for (i = 0; i < ap_threads_per_child; i++) {
+        if ((rv = worker_stack_awaken_next(stack)) != APR_SUCCESS) {
+            return rv;
+        }
+    }
+    return APR_SUCCESS;
+}
+
+static worker_stack *idle_worker_stack;
+
+#define ST_INIT              0
+#define ST_GRACEFUL          1
+#define ST_UNGRACEFUL        2
+
+static int terminate_mode = ST_INIT;
+
+static void signal_threads(int mode)
+{
+    if (terminate_mode == mode) {
+        return;
+    }
+    terminate_mode = mode;
+    mpm_state = AP_MPMQ_STOPPING;
+    workers_may_exit = 1;
+
+    worker_stack_term(idle_worker_stack);
+}
+
+AP_DECLARE(apr_status_t) ap_mpm_query(int query_code, int *result)
+{
+    switch(query_code){
+        case AP_MPMQ_MAX_DAEMON_USED:
+            *result = ap_max_daemons_limit;
+            return APR_SUCCESS;
+        case AP_MPMQ_IS_THREADED:
+            *result = AP_MPMQ_STATIC;
+            return APR_SUCCESS;
+        case AP_MPMQ_IS_FORKED:
+            *result = AP_MPMQ_DYNAMIC;
+            return APR_SUCCESS;
+        case AP_MPMQ_HARD_LIMIT_DAEMONS:
+            *result = server_limit;
+            return APR_SUCCESS;
+        case AP_MPMQ_HARD_LIMIT_THREADS:
+            *result = thread_limit;
+            return APR_SUCCESS;
+        case AP_MPMQ_MAX_THREADS:
+            *result = ap_threads_per_child;
+            return APR_SUCCESS;
+        case AP_MPMQ_MIN_SPARE_DAEMONS:
+            *result = 0;
+            return APR_SUCCESS;
+        case AP_MPMQ_MIN_SPARE_THREADS:    
+            *result = min_spare_threads;
+            return APR_SUCCESS;
+        case AP_MPMQ_MAX_SPARE_DAEMONS:
+            *result = 0;
+            return APR_SUCCESS;
+        case AP_MPMQ_MAX_SPARE_THREADS:
+            *result = max_spare_threads;
+            return APR_SUCCESS;
+        case AP_MPMQ_MAX_REQUESTS_DAEMON:
+            *result = ap_max_requests_per_child;
+            return APR_SUCCESS;
+        case AP_MPMQ_MAX_DAEMONS:
+            *result = ap_daemons_limit;
+            return APR_SUCCESS;
+        case AP_MPMQ_MPM_STATE:
+            *result = mpm_state;
+            return APR_SUCCESS;
+    }
+    return APR_ENOTIMPL;
+}
+
+/* a clean exit from a child with proper cleanup */ 
+static void clean_child_exit(int code) __attribute__ ((noreturn));
+static void clean_child_exit(int code)
+{
+    mpm_state = AP_MPMQ_STOPPING;
+    if (pchild) {
+        apr_pool_destroy(pchild);
+    }
+    ap_mpm_pod_close(pod);
+    exit(code);
+}
+
+static void just_die(int sig)
+{
+    clean_child_exit(0);
+}
+
+/*****************************************************************
+ * Connection structures and accounting...
+ */
+
+/* volatile just in case */
+static int volatile shutdown_pending;
+static int volatile restart_pending;
+static int volatile is_graceful;
+static volatile int child_fatal;
+ap_generation_t volatile ap_my_generation;
+
+/*
+ * ap_start_shutdown() and ap_start_restart(), below, are a first stab at
+ * functions to initiate shutdown or restart without relying on signals. 
+ * Previously this was initiated in sig_term() and restart() signal handlers, 
+ * but we want to be able to start a shutdown/restart from other sources --
+ * e.g. on Win32, from the service manager. Now the service manager can
+ * call ap_start_shutdown() or ap_start_restart() as appropiate.  Note that
+ * these functions can also be called by the child processes, since global
+ * variables are no longer used to pass on the required action to the parent.
+ *
+ * These should only be called from the parent process itself, since the
+ * parent process will use the shutdown_pending and restart_pending variables
+ * to determine whether to shutdown or restart. The child process should
+ * call signal_parent() directly to tell the parent to die -- this will
+ * cause neither of those variable to be set, which the parent will
+ * assume means something serious is wrong (which it will be, for the
+ * child to force an exit) and so do an exit anyway.
+ */
+
+static void ap_start_shutdown(void)
+{
+    mpm_state = AP_MPMQ_STOPPING;
+    if (shutdown_pending == 1) {
+        /* Um, is this _probably_ not an error, if the user has
+         * tried to do a shutdown twice quickly, so we won't
+         * worry about reporting it.
+         */
+        return;
+    }
+    shutdown_pending = 1;
+}
+
+/* do a graceful restart if graceful == 1 */
+static void ap_start_restart(int graceful)
+{
+    mpm_state = AP_MPMQ_STOPPING;
+    if (restart_pending == 1) {
+        /* Probably not an error - don't bother reporting it */
+        return;
+    }
+    restart_pending = 1;
+    is_graceful = graceful;
+}
+
+static void sig_term(int sig)
+{
+    if (ap_my_pid == parent_pid) {
+        ap_start_shutdown();
+    }
+    else {
+        signal_threads(ST_GRACEFUL);
+    }
+}
+
+static void restart(int sig)
+{
+    ap_start_restart(sig == AP_SIG_GRACEFUL);
+}
+
+static void set_signals(void)
+{
+#ifndef NO_USE_SIGACTION
+    struct sigaction sa;
+#endif
+
+    if (!one_process) {
+        ap_fatal_signal_setup(ap_server_conf, pconf);
+    }
+
+#ifndef NO_USE_SIGACTION
+    sigemptyset(&sa.sa_mask);
+    sa.sa_flags = 0;
+
+    sa.sa_handler = sig_term;
+    if (sigaction(SIGTERM, &sa, NULL) < 0)
+        ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, 
+                     "sigaction(SIGTERM)");
+#ifdef SIGINT
+    if (sigaction(SIGINT, &sa, NULL) < 0)
+        ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, 
+                     "sigaction(SIGINT)");
+#endif
+#ifdef SIGXCPU
+    sa.sa_handler = SIG_DFL;
+    if (sigaction(SIGXCPU, &sa, NULL) < 0)
+        ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, 
+                     "sigaction(SIGXCPU)");
+#endif
+#ifdef SIGXFSZ
+    sa.sa_handler = SIG_DFL;
+    if (sigaction(SIGXFSZ, &sa, NULL) < 0)
+        ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, 
+                     "sigaction(SIGXFSZ)");
+#endif
+#ifdef SIGPIPE
+    sa.sa_handler = SIG_IGN;
+    if (sigaction(SIGPIPE, &sa, NULL) < 0)
+        ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, 
+                     "sigaction(SIGPIPE)");
+#endif
+
+    /* we want to ignore HUPs and AP_SIG_GRACEFUL while we're busy 
+     * processing one */
+    sigaddset(&sa.sa_mask, SIGHUP);
+    sigaddset(&sa.sa_mask, AP_SIG_GRACEFUL);
+    sa.sa_handler = restart;
+    if (sigaction(SIGHUP, &sa, NULL) < 0)
+        ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, 
+                     "sigaction(SIGHUP)");
+    if (sigaction(AP_SIG_GRACEFUL, &sa, NULL) < 0)
+        ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, 
+                     "sigaction(" AP_SIG_GRACEFUL_STRING ")");
+#else
+    if (!one_process) {
+#ifdef SIGXCPU
+        apr_signal(SIGXCPU, SIG_DFL);
+#endif /* SIGXCPU */
+#ifdef SIGXFSZ
+        apr_signal(SIGXFSZ, SIG_DFL);
+#endif /* SIGXFSZ */
+    }
+
+    apr_signal(SIGTERM, sig_term);
+#ifdef SIGHUP
+    apr_signal(SIGHUP, restart);
+#endif /* SIGHUP */
+#ifdef AP_SIG_GRACEFUL
+    apr_signal(AP_SIG_GRACEFUL, restart);
+#endif /* AP_SIG_GRACEFUL */
+#ifdef SIGPIPE
+    apr_signal(SIGPIPE, SIG_IGN);
+#endif /* SIGPIPE */
+
+#endif
+}
+
+/*****************************************************************
+ * Here follows a long bunch of generic server bookkeeping stuff...
+ */
+
+int ap_graceful_stop_signalled(void)
+    /* XXX this is really a bad confusing obsolete name
+     * maybe it should be ap_mpm_process_exiting?
+     */
+{
+    return workers_may_exit;
+}
+
+/*****************************************************************
+ * Child process main loop.
+ */
+
+static void process_socket(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);
+    int csd;
+    ap_sb_handle_t *sbh;
+
+    ap_create_sb_handle(&sbh, p, my_child_num, my_thread_num);
+    apr_os_sock_get(&csd, sock);
+
+    current_conn = ap_run_create_connection(p, ap_server_conf, sock,
+                                            conn_id, sbh, bucket_alloc);
+    if (current_conn) {
+        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
+   "MaxRequestsPerChild 0", and keep going in that case.  Doing it this way
+   simplifies the hot path in worker_thread */
+static void check_infinite_requests(void)
+{
+    if (ap_max_requests_per_child) {
+        signal_threads(ST_GRACEFUL);
+    }
+    else {
+        /* wow! if you're executing this code, you may have set a record.
+         * either this child process has served over 2 billion requests, or
+         * you're running a threaded 2.0 on a 16 bit machine.  
+         *
+         * I'll buy pizza and beers at Apachecon for the first person to do
+         * the former without cheating (dorking with INT_MAX, or running with
+         * uncommitted performance patches, for example).    
+         *
+         * for the latter case, you probably deserve a beer too.   Greg Ames
+         */
+            
+        requests_this_child = INT_MAX;      /* keep going */ 
+    }
+}
+
+static void unblock_signal(int sig)
+{
+    sigset_t sig_mask;
+
+    sigemptyset(&sig_mask);
+    sigaddset(&sig_mask, sig);
+#if defined(SIGPROCMASK_SETS_THREAD_MASK)
+    sigprocmask(SIG_UNBLOCK, &sig_mask, NULL);
+#else
+    pthread_sigmask(SIG_UNBLOCK, &sig_mask, NULL);
+#endif
+}
+
+static void *worker_thread(apr_thread_t *thd, void * dummy)
+{
+    proc_info * ti = dummy;
+    int process_slot = ti->pid;
+    int thread_slot = ti->tid;
+    apr_uint32_t my_worker_num = (apr_uint32_t)(ti->tid);
+    apr_pool_t *tpool = apr_thread_pool_get(thd);
+    void *csd = NULL;
+    apr_allocator_t *allocator;
+    apr_pool_t *ptrans;                /* Pool for per-transaction stuff */
+    apr_bucket_alloc_t *bucket_alloc;
+    int n;
+    apr_pollfd_t *pollset;
+    apr_status_t rv;
+    ap_listen_rec *lr, *last_lr = ap_listeners;
+    int is_listener;
+
+    ap_update_child_status_from_indexes(process_slot, thread_slot, SERVER_STARTING, NULL);
+
+    free(ti);
+
+    apr_allocator_create(&allocator);
+    apr_allocator_max_free_set(allocator, ap_max_mem_free);
+    /* XXX: why is ptrans's parent not tpool?  --jcw 08/2003 */
+    apr_pool_create_ex(&ptrans, NULL, NULL, allocator);
+    apr_allocator_owner_set(allocator, ptrans);
+    bucket_alloc = apr_bucket_alloc_create_ex(allocator);
+
+    apr_poll_setup(&pollset, num_listensocks, tpool);
+    for(lr = ap_listeners ; lr != NULL ; lr = lr->next)
+        apr_poll_socket_add(pollset, lr->sd, APR_POLLIN);
+
+    /* TODO: Switch to a system where threads reuse the results from earlier
+       poll calls - manoj */
+    is_listener = 0;
+    while (!workers_may_exit) {
+
+        ap_update_child_status_from_indexes(process_slot, thread_slot,
+                                            SERVER_READY, NULL);
+        if (!is_listener) {
+            /* Wait until it's our turn to become the listener */
+            if ((rv = worker_stack_wait(idle_worker_stack, my_worker_num)) !=
+                APR_SUCCESS) {
+                if (rv != APR_EINVAL) {
+                    ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf,
+                                 "worker_stack_wait failed. Shutting down");
+                }
+                break;
+            }
+            if (workers_may_exit) {
+                break;
+            }
+            is_listener = 1;
+        }
+
+        /* TODO: requests_this_child should be synchronized - aaron */
+        if (requests_this_child <= 0) {
+            check_infinite_requests();
+        }
+        if (workers_may_exit) break;
+
+        if ((rv = SAFE_ACCEPT(apr_proc_mutex_lock(accept_mutex)))
+            != APR_SUCCESS) {
+            int level = APLOG_EMERG;
+
+            if (workers_may_exit) {
+                break;
+            }
+            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,
+                         "apr_proc_mutex_lock failed. Attempting to shutdown "
+                         "process gracefully.");
+            signal_threads(ST_GRACEFUL);
+            break;                    /* skip the lock release */
+        }
+
+        if (!ap_listeners->next) {
+            /* Only one listener, so skip the poll */
+            lr = ap_listeners;
+        }
+        else {
+            while (!workers_may_exit) {
+                apr_status_t ret;
+                apr_int16_t event;
+
+                ret = apr_poll(pollset, num_listensocks, &n, -1);
+                if (ret != APR_SUCCESS) {
+                    if (APR_STATUS_IS_EINTR(ret)) {
+                        continue;
+                    }
+
+                    /* apr_poll() will only return errors in catastrophic
+                     * circumstances. Let's try exiting gracefully, for now. */
+                    ap_log_error(APLOG_MARK, APLOG_ERR, ret, (const server_rec *)
+                                 ap_server_conf, "apr_poll: (listen)");
+                    signal_threads(ST_GRACEFUL);
+                }
+
+                if (workers_may_exit) break;
+
+                /* find a listener */
+                lr = last_lr;
+                do {
+                    lr = lr->next;
+                    if (lr == NULL) {
+                        lr = ap_listeners;
+                    }
+                    /* XXX: Should we check for POLLERR? */
+                    apr_poll_revents_get(&event, lr->sd, pollset);
+                    if (event & APR_POLLIN) {
+                        last_lr = lr;
+                        goto got_fd;
+                    }
+                } while (lr != last_lr);
+            }
+        }
+    got_fd:
+        if (!workers_may_exit) {
+            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(accept_mutex)))
+                != APR_SUCCESS) {
+                int level = APLOG_EMERG;
+
+                if (workers_may_exit) {
+                    break;
+                }
+                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,
+                             "apr_proc_mutex_unlock failed. Attempting to "
+                             "shutdown process gracefully.");
+                signal_threads(ST_GRACEFUL);
+            }
+            if (csd != NULL) {
+                is_listener = 0;
+                worker_stack_awaken_next(idle_worker_stack);
+                process_socket(ptrans, csd, process_slot,
+                               thread_slot, bucket_alloc);
+                apr_pool_clear(ptrans);
+                requests_this_child--;
+            }
+            if ((ap_mpm_pod_check(pod) == APR_SUCCESS) ||
+                (ap_my_generation !=
+                 ap_scoreboard_image->global->running_generation)) {
+                signal_threads(ST_GRACEFUL);
+                break;
+            }
+        }
+        else {
+            if ((rv = SAFE_ACCEPT(apr_proc_mutex_unlock(accept_mutex)))
+                != APR_SUCCESS) {
+                ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf,
+                             "apr_proc_mutex_unlock failed. Attempting to "
+                             "shutdown process gracefully.");
+                signal_threads(ST_GRACEFUL);
+            }
+            break;
+        }
+    }
+
+    dying = 1;
+    ap_scoreboard_image->parent[process_slot].quiescing = 1;
+
+    worker_stack_term(idle_worker_stack);
+
+    ap_update_child_status_from_indexes(process_slot, thread_slot,
+        (dying) ? SERVER_DEAD : SERVER_GRACEFUL, (request_rec *) NULL);
+
+    apr_bucket_alloc_destroy(bucket_alloc);
+
+    apr_thread_exit(thd, APR_SUCCESS);
+    return NULL;
+}
+
+static int check_signal(int signum)
+{
+    switch (signum) {
+    case SIGTERM:
+    case SIGINT:
+        return 1;
+    }
+    return 0;
+}
+
+/* XXX under some circumstances not understood, children can get stuck
+ *     in start_threads forever trying to take over slots which will
+ *     never be cleaned up; for now there is an APLOG_DEBUG message issued
+ *     every so often when this condition occurs
+ */
+static void * APR_THREAD_FUNC start_threads(apr_thread_t *thd, void *dummy)
+{
+    thread_starter *ts = dummy;
+    apr_thread_t **threads = ts->threads;
+    apr_threadattr_t *thread_attr = ts->threadattr;
+    int child_num_arg = ts->child_num_arg;
+    int my_child_num = child_num_arg;
+    proc_info *my_info;
+    apr_status_t rv;
+    int i;
+    int threads_created = 0;
+    int loops;
+    int prev_threads_created;
+
+    idle_worker_stack = worker_stack_create(pchild, ap_threads_per_child);
+    if (idle_worker_stack == NULL) {
+        ap_log_error(APLOG_MARK, APLOG_ALERT, 0, ap_server_conf,
+                     "worker_stack_create() failed");
+        clean_child_exit(APEXIT_CHILDFATAL);
+    }
+
+    worker_wakeups = (worker_wakeup_info **)
+        apr_palloc(pchild, sizeof(worker_wakeup_info *) *
+                   ap_threads_per_child);
+
+    loops = prev_threads_created = 0;
+    while (1) {
+        for (i = 0; i < ap_threads_per_child; i++) {
+            int status = ap_scoreboard_image->servers[child_num_arg][i].status;
+            worker_wakeup_info *wakeup;
+
+            if (status != SERVER_GRACEFUL && status != SERVER_DEAD) {
+                continue;
+            }
+
+            wakeup = worker_wakeup_create(pchild);
+            if (wakeup == NULL) {
+                ap_log_error(APLOG_MARK, APLOG_ALERT|APLOG_NOERRNO, 0,
+                             ap_server_conf, "worker_wakeup_create failed");
+                clean_child_exit(APEXIT_CHILDFATAL);
+            }
+            worker_wakeups[threads_created] = wakeup;
+            my_info = (proc_info *)malloc(sizeof(proc_info));
+            if (my_info == NULL) {
+                ap_log_error(APLOG_MARK, APLOG_ALERT, errno, ap_server_conf,
+                             "malloc: out of memory");
+                clean_child_exit(APEXIT_CHILDFATAL);
+            }
+            my_info->pid = my_child_num;
+            my_info->tid = i;
+            my_info->sd = 0;
+        
+            /* We are creating threads right now */
+            ap_update_child_status_from_indexes(my_child_num, i,
+                                                SERVER_STARTING, NULL);
+            /* We let each thread update its own scoreboard entry.  This is
+             * done because it lets us deal with tid better.
+             */
+            rv = apr_thread_create(&threads[i], thread_attr, 
+                                   worker_thread, my_info, pchild);
+            if (rv != APR_SUCCESS) {
+                ap_log_error(APLOG_MARK, APLOG_ALERT, rv, ap_server_conf,
+                    "apr_thread_create: unable to create worker thread");
+                /* 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 if we exit. */
+                apr_sleep(10 * APR_USEC_PER_SEC);
+                clean_child_exit(APEXIT_CHILDFATAL);
+            }
+            threads_created++;
+        }
+        if (start_thread_may_exit || threads_created == ap_threads_per_child) {
+            break;
+        }
+        /* wait for previous generation to clean up an entry */
+        apr_sleep(1 * APR_USEC_PER_SEC);
+        ++loops;
+        if (loops % 120 == 0) { /* every couple of minutes */
+            if (prev_threads_created == threads_created) {
+                ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf,
+                             "child %" APR_PID_T_FMT " isn't taking over "
+                             "slots very quickly (%d of %d)",
+                             ap_my_pid, threads_created, ap_threads_per_child);
+            }
+            prev_threads_created = threads_created;
+        }
+    }
+    
+    /* What state should this child_main process be listed as in the 
+     * scoreboard...?
+     *  ap_update_child_status_from_indexes(my_child_num, i, SERVER_STARTING, 
+     *                                      (request_rec *) NULL);
+     * 
+     *  This state should be listed separately in the scoreboard, in some kind
+     *  of process_status, not mixed in with the worker threads' status.   
+     *  "life_status" is almost right, but it's in the worker's structure, and 
+     *  the name could be clearer.   gla
+     */
+    apr_thread_exit(thd, APR_SUCCESS);
+    return NULL;
+}
+
+static void join_workers(apr_thread_t **threads)
+{
+    int i;
+    apr_status_t rv, thread_rv;
+
+    for (i = 0; i < ap_threads_per_child; i++) {
+        if (threads[i]) { /* if we ever created this thread */
+            rv = apr_thread_join(&thread_rv, threads[i]);
+            if (rv != APR_SUCCESS) {
+                ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ap_server_conf,
+                             "apr_thread_join: unable to join worker "
+                             "thread %d",
+                             i);
+            }
+        }
+    }
+}
+
+static void join_start_thread(apr_thread_t *start_thread_id)
+{
+    apr_status_t rv, thread_rv;
+
+    start_thread_may_exit = 1; /* tell it to give up in case it is still 
+                                * trying to take over slots from a 
+                                * previous generation
+                                */
+    rv = apr_thread_join(&thread_rv, start_thread_id);
+    if (rv != APR_SUCCESS) {
+        ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ap_server_conf,
+                     "apr_thread_join: unable to join the start "
+                     "thread");
+    }
+}
+
+static void child_main(int child_num_arg)
+{
+    apr_thread_t **threads;
+    apr_status_t rv;
+    thread_starter *ts;
+    apr_threadattr_t *thread_attr;
+    apr_thread_t *start_thread_id;
+
+    mpm_state = AP_MPMQ_STARTING; /* for benefit of any hooks that run as this
+                                  * child initializes
+                                  */
+
+    ap_my_pid = getpid();
+    ap_fatal_signal_child_setup(ap_server_conf);
+    apr_pool_create(&pchild, pconf);
+
+    /*stuff to do before we switch id's, so we have permissions.*/
+    ap_reopen_scoreboard(pchild, NULL, 0);
+
+    rv = SAFE_ACCEPT(apr_proc_mutex_child_init(&accept_mutex, ap_lock_fname,
+                                               pchild));
+    if (rv != APR_SUCCESS) {
+        ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf,
+                     "Couldn't initialize cross-process lock in child");
+        clean_child_exit(APEXIT_CHILDFATAL);
+    }
+
+    if (unixd_setup_child()) {
+        clean_child_exit(APEXIT_CHILDFATAL);
+    }
+
+    ap_run_child_init(pchild, ap_server_conf);
+
+    /* done with init critical section */
+
+    /* Just use the standard apr_setup_signal_thread to block all signals
+     * from being received.  The child processes no longer use signals for
+     * any communication with the parent process.
+     */
+    rv = apr_setup_signal_thread();
+    if (rv != APR_SUCCESS) {
+        ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf,
+                     "Couldn't initialize signal thread");
+        clean_child_exit(APEXIT_CHILDFATAL);
+    }
+
+    if (ap_max_requests_per_child) {
+        requests_this_child = ap_max_requests_per_child;
+    }
+    else {
+        /* coding a value of zero means infinity */
+        requests_this_child = INT_MAX;
+    }
+    
+    /* Setup worker threads */
+
+    /* clear the storage; we may not create all our threads immediately, 
+     * and we want a 0 entry to indicate a thread which was not created
+     */
+    threads = (apr_thread_t **)calloc(1, 
+                                sizeof(apr_thread_t *) * ap_threads_per_child);
+    if (threads == NULL) {
+        ap_log_error(APLOG_MARK, APLOG_ALERT, errno, ap_server_conf,
+                     "malloc: out of memory");
+        clean_child_exit(APEXIT_CHILDFATAL);
+    }
+
+    ts = (thread_starter *)apr_palloc(pchild, sizeof(*ts));
+
+    apr_threadattr_create(&thread_attr, pchild);
+    /* 0 means PTHREAD_CREATE_JOINABLE */
+    apr_threadattr_detach_set(thread_attr, 0);
+
+    ts->threads = threads;
+    ts->child_num_arg = child_num_arg;
+    ts->threadattr = thread_attr;
+
+    rv = apr_thread_create(&start_thread_id, thread_attr, start_threads,
+                           ts, pchild);
+    if (rv != APR_SUCCESS) {
+        ap_log_error(APLOG_MARK, APLOG_ALERT, rv, ap_server_conf,
+                     "apr_thread_create: unable to create worker thread");
+        /* 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 if we exit. */
+        apr_sleep(10 * APR_USEC_PER_SEC);
+        clean_child_exit(APEXIT_CHILDFATAL);
+    }
+
+    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(threads);
+    }
+    else { /* !one_process */
+        /* remove SIGTERM from the set of blocked signals...  if one of
+         * the other threads in the process needs to take us down
+         * (e.g., for MaxRequestsPerChild) it will send us SIGTERM
+         */
+        unblock_signal(SIGTERM);
+        join_start_thread(start_thread_id);
+        join_workers(threads);
+    }
+
+    free(threads);
+
+    clean_child_exit(resource_shortage ? APEXIT_CHILDSICK : 0);
+}
+
+static int make_child(server_rec *s, int slot) 
+{
+    int pid;
+
+    if (slot + 1 > ap_max_daemons_limit) {
+        ap_max_daemons_limit = slot + 1;
+    }
+
+    if (one_process) {
+        set_signals();
+        ap_scoreboard_image->parent[slot].pid = getpid();
+        child_main(slot);
+    }
+
+    if ((pid = fork()) == -1) {
+        ap_log_error(APLOG_MARK, APLOG_ERR, errno, s, 
+                     "fork: Unable to fork new process");
+
+        /* fork didn't succeed. Fix the scoreboard or else
+         * it will say SERVER_STARTING forever and ever
+         */
+        ap_update_child_status_from_indexes(slot, 0, SERVER_DEAD, NULL);
+
+        /* In case system resources are maxxed out, we don't want
+           Apache running away with the CPU trying to fork over and
+           over and over again. */
+        apr_sleep(10 * APR_USEC_PER_SEC);
+
+        return -1;
+    }
+
+    if (!pid) {
+#ifdef HAVE_BINDPROCESSOR
+        /* By default, AIX binds to a single processor.  This bit unbinds
+         * children which will then bind to another CPU.
+         */
+        int status = bindprocessor(BINDPROCESS, (int)getpid(),
+                               PROCESSOR_CLASS_ANY);
+        if (status != OK)
+            ap_log_error(APLOG_MARK, APLOG_WARNING, errno, 
+                         ap_server_conf,
+                         "processor unbind failed %d", status);
+#endif
+        RAISE_SIGSTOP(MAKE_CHILD);
+
+        apr_signal(SIGTERM, just_die);
+        child_main(slot);
+
+        clean_child_exit(0);
+    }
+    /* else */
+    ap_scoreboard_image->parent[slot].quiescing = 0;
+    ap_scoreboard_image->parent[slot].pid = pid;
+    return 0;
+}
+
+/* start up a bunch of children */
+static void startup_children(int number_to_start)
+{
+    int i;
+
+    for (i = 0; number_to_start && i < ap_daemons_limit; ++i) {
+        if (ap_scoreboard_image->parent[i].pid != 0) {
+            continue;
+        }
+        if (make_child(ap_server_conf, i) < 0) {
+            break;
+        }
+        --number_to_start;
+    }
+}
+
+
+/*
+ * idle_spawn_rate is the number of children that will be spawned on the
+ * next maintenance cycle if there aren't enough idle servers.  It is
+ * doubled up to MAX_SPAWN_RATE, and reset only when a cycle goes by
+ * without the need to spawn.
+ */
+static int idle_spawn_rate = 1;
+#ifndef MAX_SPAWN_RATE
+#define MAX_SPAWN_RATE        (32)
+#endif
+static int hold_off_on_exponential_spawning;
+
+static void perform_idle_server_maintenance(void)
+{
+    int i, j;
+    int idle_thread_count;
+    worker_score *ws;
+    process_score *ps;
+    int free_length;
+    int totally_free_length = 0;
+    int free_slots[MAX_SPAWN_RATE];
+    int last_non_dead;
+    int total_non_dead;
+
+    /* initialize the free_list */
+    free_length = 0;
+
+    idle_thread_count = 0;
+    last_non_dead = -1;
+    total_non_dead = 0;
+
+    for (i = 0; i < ap_daemons_limit; ++i) {
+        /* Initialization to satisfy the compiler. It doesn't know
+         * that ap_threads_per_child is always > 0 */
+        int status = SERVER_DEAD;
+        int any_dying_threads = 0;
+        int any_dead_threads = 0;
+        int all_dead_threads = 1;
+
+        if (i >= ap_max_daemons_limit && totally_free_length == idle_spawn_rate)
+            break;
+        ps = &ap_scoreboard_image->parent[i];
+        for (j = 0; j < ap_threads_per_child; j++) {
+            ws = &ap_scoreboard_image->servers[i][j];
+            status = ws->status;
+
+            /* XXX any_dying_threads is probably no longer needed    GLA */
+            any_dying_threads = any_dying_threads || 
+                                (status == SERVER_GRACEFUL);
+            any_dead_threads = any_dead_threads || (status == SERVER_DEAD);
+            all_dead_threads = all_dead_threads &&
+                                   (status == SERVER_DEAD ||
+                                    status == SERVER_GRACEFUL);
+
+            /* We consider a starting server as idle because we started it
+             * at least a cycle ago, and if it still hasn't finished starting
+             * then we're just going to swamp things worse by forking more.
+             * So we hopefully won't need to fork more if we count it.
+             * This depends on the ordering of SERVER_READY and SERVER_STARTING.
+             */
+            if (status <= SERVER_READY && status != SERVER_DEAD &&
+                    !ps->quiescing &&
+                    ps->generation == ap_my_generation &&
+                 /* XXX the following shouldn't be necessary if we clean up 
+                  *     properly after seg faults, but we're not yet    GLA 
+                  */     
+                    ps->pid != 0) {
+                ++idle_thread_count;
+            }
+        }
+        if (any_dead_threads && totally_free_length < idle_spawn_rate 
+                && (!ps->pid               /* no process in the slot */
+                    || ps->quiescing)) {   /* or at least one is going away */
+            if (all_dead_threads) {
+                /* great! we prefer these, because the new process can
+                 * start more threads sooner.  So prioritize this slot 
+                 * by putting it ahead of any slots with active threads.
+                 *
+                 * first, make room by moving a slot that's potentially still
+                 * in use to the end of the array
+                 */
+                free_slots[free_length] = free_slots[totally_free_length];
+                free_slots[totally_free_length++] = i;
+            }
+            else {
+                /* slot is still in use - back of the bus
+                 */
+            free_slots[free_length] = i;
+            }
+            ++free_length;
+        }
+        /* XXX if (!ps->quiescing)     is probably more reliable  GLA */
+        if (!any_dying_threads) {
+            last_non_dead = i;
+            ++total_non_dead;
+        }
+    }
+    ap_max_daemons_limit = last_non_dead + 1;
+
+    if (idle_thread_count > max_spare_threads) {
+        /* Kill off one child */
+        ap_mpm_pod_signal(pod);
+        idle_spawn_rate = 1;
+    }
+    else if (idle_thread_count < min_spare_threads) {
+        /* terminate the free list */
+        if (free_length == 0) {
+            /* only report this condition once */
+            static int reported = 0;
+            
+            if (!reported) {
+                ap_log_error(APLOG_MARK, APLOG_ERR, 0, 
+                             ap_server_conf,
+                             "server reached MaxClients setting, consider"
+                             " raising the MaxClients setting");
+                reported = 1;
+            }
+            idle_spawn_rate = 1;
+        }
+        else {
+            if (free_length > idle_spawn_rate) {
+                free_length = idle_spawn_rate;
+            }
+            if (idle_spawn_rate >= 8) {
+                ap_log_error(APLOG_MARK, APLOG_INFO, 0, 
+                             ap_server_conf,
+                             "server seems busy, (you may need "
+                             "to increase StartServers, ThreadsPerChild "
+                             "or Min/MaxSpareThreads), "
+                             "spawning %d children, there are around %d idle "
+                             "threads, and %d total children", free_length,
+                             idle_thread_count, total_non_dead);
+            }
+            for (i = 0; i < free_length; ++i) {
+                make_child(ap_server_conf, free_slots[i]);
+            }
+            /* the next time around we want to spawn twice as many if this
+             * wasn't good enough, but not if we've just done a graceful
+             */
+            if (hold_off_on_exponential_spawning) {
+                --hold_off_on_exponential_spawning;
+            }
+            else if (idle_spawn_rate < MAX_SPAWN_RATE) {
+                idle_spawn_rate *= 2;
+            }
+        }
+    }
+    else {
+      idle_spawn_rate = 1;
+    }
+}
+
+static void server_main_loop(int remaining_children_to_start)
+{
+    int child_slot;
+    apr_exit_why_e exitwhy;
+    int status, processed_status;
+    apr_proc_t pid;
+    int i;
+
+    while (!restart_pending && !shutdown_pending) {
+        ap_wait_or_timeout(&exitwhy, &status, &pid, pconf);
+        
+        if (pid.pid != -1) {
+            processed_status = ap_process_child_status(&pid, exitwhy, status);
+            if (processed_status == APEXIT_CHILDFATAL) {
+                shutdown_pending = 1;
+                child_fatal = 1;
+                return;
+            }
+            /* non-fatal death... note that it's gone in the scoreboard. */
+            child_slot = find_child_by_pid(&pid);
+            if (child_slot >= 0) {
+                for (i = 0; i < ap_threads_per_child; i++)
+                    ap_update_child_status_from_indexes(child_slot, i, SERVER_DEAD, 
+                                                        (request_rec *) NULL);
+                
+                ap_scoreboard_image->parent[child_slot].pid = 0;
+                ap_scoreboard_image->parent[child_slot].quiescing = 0;
+                if (processed_status == APEXIT_CHILDSICK) {
+                    /* resource shortage, minimize the fork rate */
+                    idle_spawn_rate = 1;
+                }
+                else if (remaining_children_to_start
+                    && child_slot < ap_daemons_limit) {
+                    /* we're still doing a 1-for-1 replacement of dead
+                     * children with new children
+                     */
+                    make_child(ap_server_conf, child_slot);
+                    --remaining_children_to_start;
+                }
+#if APR_HAS_OTHER_CHILD
+            }
+            else if (apr_proc_other_child_read(&pid, status) == 0) {
+                /* handled */
+#endif
+            }
+            else if (is_graceful) {
+                /* Great, we've probably just lost a slot in the
+                 * scoreboard.  Somehow we don't know about this child.
+                 */
+                ap_log_error(APLOG_MARK, APLOG_WARNING, 0,
+                             ap_server_conf,
+                             "long lost child came home! (pid %ld)",
+                             (long)pid.pid);
+            }
+            /* Don't perform idle maintenance when a child dies,
+             * only do it when there's a timeout.  Remember only a
+             * finite number of children can die, and it's pretty
+             * pathological for a lot to die suddenly.
+             */
+            continue;
+        }
+        else if (remaining_children_to_start) {
+            /* we hit a 1 second timeout in which none of the previous
+             * generation of children needed to be reaped... so assume
+             * they're all done, and pick up the slack if any is left.
+             */
+            startup_children(remaining_children_to_start);
+            remaining_children_to_start = 0;
+            /* In any event we really shouldn't do the code below because
+             * few of the servers we just started are in the IDLE state
+             * yet, so we'd mistakenly create an extra server.
+             */
+            continue;
+        }
+
+        perform_idle_server_maintenance();
+    }
+}
+
+int ap_mpm_run(apr_pool_t *_pconf, apr_pool_t *plog, server_rec *s)
+{
+    int remaining_children_to_start;
+    apr_status_t rv;
+
+    ap_log_pid(pconf, ap_pid_fname);
+
+    first_server_limit = server_limit;
+    first_thread_limit = thread_limit;
+    if (changed_limit_at_restart) {
+        ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s,
+                     "WARNING: Attempt to change ServerLimit or ThreadLimit "
+                     "ignored during restart");
+        changed_limit_at_restart = 0;
+    }
+    
+    /* Initialize cross-process accept lock */
+    ap_lock_fname = apr_psprintf(_pconf, "%s.%" APR_PID_T_FMT,
+                                 ap_server_root_relative(_pconf, ap_lock_fname),
+                                 ap_my_pid);
+
+    rv = apr_proc_mutex_create(&accept_mutex, ap_lock_fname, 
+                               ap_accept_lock_mech, _pconf);
+    if (rv != APR_SUCCESS) {
+        ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s,
+                     "Couldn't create accept lock");
+        mpm_state = AP_MPMQ_STOPPING;
+        return 1;
+    }
+
+#if APR_USE_SYSVSEM_SERIALIZE
+    if (ap_accept_lock_mech == APR_LOCK_DEFAULT || 
+        ap_accept_lock_mech == APR_LOCK_SYSVSEM) {
+#else
+    if (ap_accept_lock_mech == APR_LOCK_SYSVSEM) {
+#endif
+        rv = unixd_set_proc_mutex_perms(accept_mutex);
+        if (rv != APR_SUCCESS) {
+            ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s,
+                         "Couldn't set permissions on cross-process lock; "
+                         "check User and Group directives");
+            mpm_state = AP_MPMQ_STOPPING;
+            return 1;
+        }
+    }
+
+    if (!is_graceful) {
+        if (ap_run_pre_mpm(s->process->pool, SB_SHARED) != OK) {
+            mpm_state = AP_MPMQ_STOPPING;
+            return 1;
+        }
+        /* fix the generation number in the global score; we just got a new,
+         * cleared scoreboard
+         */
+        ap_scoreboard_image->global->running_generation = ap_my_generation;
+    }
+
+    set_signals();
+    /* Don't thrash... */
+    if (max_spare_threads < min_spare_threads + ap_threads_per_child)
+        max_spare_threads = min_spare_threads + ap_threads_per_child;
+
+    /* If we're doing a graceful_restart then we're going to see a lot
+     * of children exiting immediately when we get into the main loop
+     * below (because we just sent them AP_SIG_GRACEFUL).  This happens pretty
+     * rapidly... and for each one that exits we'll start a new one until
+     * we reach at least daemons_min_free.  But we may be permitted to
+     * start more than that, so we'll just keep track of how many we're
+     * supposed to start up without the 1 second penalty between each fork.
+     */
+    remaining_children_to_start = ap_daemons_to_start;
+    if (remaining_children_to_start > ap_daemons_limit) {
+        remaining_children_to_start = ap_daemons_limit;
+    }
+    if (!is_graceful) {
+        startup_children(remaining_children_to_start);
+        remaining_children_to_start = 0;
+    }
+    else {
+        /* give the system some time to recover before kicking into
+            * exponential mode */
+        hold_off_on_exponential_spawning = 10;
+    }
+
+    ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, ap_server_conf,
+                "%s configured -- resuming normal operations",
+                ap_get_server_version());
+    ap_log_error(APLOG_MARK, APLOG_INFO, 0, ap_server_conf,
+                "Server built: %s", ap_get_server_built());
+#ifdef AP_MPM_WANT_SET_ACCEPT_LOCK_MECH
+    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf,
+		"AcceptMutex: %s (default: %s)",
+		apr_proc_mutex_name(accept_mutex),
+		apr_proc_mutex_defname());
+#endif
+    restart_pending = shutdown_pending = 0;
+    mpm_state = AP_MPMQ_RUNNING;
+
+    server_main_loop(remaining_children_to_start);
+    mpm_state = AP_MPMQ_STOPPING;
+
+    if (shutdown_pending) {
+        /* Time to gracefully shut down:
+         * Kill child processes, tell them to call child_exit, etc...
+         * (By "gracefully" we don't mean graceful in the same sense as 
+         * "apachectl graceful" where we allow old connections to finish.)
+         */
+	if (unixd_killpg(getpgrp(), SIGTERM) < 0) {
+	    ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "killpg SIGTERM");
+	}
+        ap_reclaim_child_processes(1);                /* Start with SIGTERM */
+
+        if (!child_fatal) {
+            /* cleanup pid file on normal shutdown */
+            const char *pidfile = NULL;
+            pidfile = ap_server_root_relative (pconf, ap_pid_fname);
+            if ( pidfile != NULL && unlink(pidfile) == 0)
+                ap_log_error(APLOG_MARK, APLOG_INFO, 0,
+                             ap_server_conf,
+                             "removed PID file %s (pid=%ld)",
+                             pidfile, (long)getpid());
+    
+            ap_log_error(APLOG_MARK, APLOG_NOTICE, 0,
+                         ap_server_conf, "caught SIGTERM, shutting down");
+        }
+        return 1;
+    }
+
+    /* we've been told to restart */
+    apr_signal(SIGHUP, SIG_IGN);
+
+    if (one_process) {
+        /* not worth thinking about */
+        return 1;
+    }
+
+    /* advance to the next generation */
+    /* XXX: we really need to make sure this new generation number isn't in
+     * use by any of the children.
+     */
+    ++ap_my_generation;
+    ap_scoreboard_image->global->running_generation = ap_my_generation;
+    
+    if (is_graceful) {
+        ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, ap_server_conf,
+                     AP_SIG_GRACEFUL_STRING " received.  Doing graceful restart");
+        /* wake up the children...time to die.  But we'll have more soon */
+        ap_mpm_pod_killpg(pod, ap_daemons_limit);
+    
+
+        /* This is mostly for debugging... so that we know what is still
+         * gracefully dealing with existing request.
+         */
+        
+    }
+    else {
+        /* Kill 'em all.  Since the child acts the same on the parents SIGTERM 
+         * and a SIGHUP, we may as well use the same signal, because some user
+         * pthreads are stealing signals from us left and right.
+         */
+        ap_mpm_pod_killpg(pod, ap_daemons_limit);
+
+        ap_reclaim_child_processes(1);                /* Start with SIGTERM */
+        ap_log_error(APLOG_MARK, APLOG_NOTICE, 0, ap_server_conf,
+                    "SIGHUP received.  Attempting to restart");
+    }
+
+    return 0;
+}
+
+/* This really should be a post_config hook, but the error log is already
+ * redirected by that point, so we need to do this in the open_logs phase.
+ */
+static int leader_open_logs(apr_pool_t *p, apr_pool_t *plog, apr_pool_t *ptemp, server_rec *s)
+{
+    apr_status_t rv;
+
+    pconf = p;
+    ap_server_conf = s;
+
+    if ((num_listensocks = ap_setup_listeners(ap_server_conf)) < 1) {
+        ap_log_error(APLOG_MARK, APLOG_ALERT|APLOG_STARTUP, 0,
+                     NULL, "no listening sockets available, shutting down");
+        return DONE;
+    }
+
+    if (!one_process) {
+        if ((rv = ap_mpm_pod_open(pconf, &pod))) {
+            ap_log_error(APLOG_MARK, APLOG_CRIT|APLOG_STARTUP, rv, NULL,
+                    "Could not open pipe-of-death.");
+            return DONE;
+        }
+    }
+    return OK;
+}
+
+static int leader_pre_config(apr_pool_t *pconf, apr_pool_t *plog, 
+                             apr_pool_t *ptemp)
+{
+    static int restart_num = 0;
+    int no_detach, debug, foreground;
+    ap_directive_t *pdir;
+    ap_directive_t *max_clients = NULL;
+    apr_status_t rv;
+
+    mpm_state = AP_MPMQ_STARTING;
+
+    /* make sure that "ThreadsPerChild" gets set before "MaxClients" */
+    for (pdir = ap_conftree; pdir != NULL; pdir = pdir->next) {
+        if (strncasecmp(pdir->directive, "ThreadsPerChild", 15) == 0) {
+            if (!max_clients) {
+                break; /* we're in the clear, got ThreadsPerChild first */
+            }
+            else {
+                /* now to swap the data */
+                ap_directive_t temp;
+
+                temp.directive = pdir->directive;
+                temp.args = pdir->args;
+                /* Make sure you don't change 'next', or you may get loops! */
+                /* XXX: first_child, parent, and data can never be set
+                 * for these directives, right? -aaron */
+                temp.filename = pdir->filename;
+                temp.line_num = pdir->line_num;
+
+                pdir->directive = max_clients->directive;
+                pdir->args = max_clients->args;
+                pdir->filename = max_clients->filename;
+                pdir->line_num = max_clients->line_num;
+                
+                max_clients->directive = temp.directive;
+                max_clients->args = temp.args;
+                max_clients->filename = temp.filename;
+                max_clients->line_num = temp.line_num;
+                break;
+            }
+        }
+        else if (!max_clients
+                 && strncasecmp(pdir->directive, "MaxClients", 10) == 0) {
+            max_clients = pdir;
+        }
+    }
+
+    debug = ap_exists_config_define("DEBUG");
+
+    if (debug) {
+        foreground = one_process = 1;
+        no_detach = 0;
+    }
+    else {
+        one_process = ap_exists_config_define("ONE_PROCESS");
+        no_detach = ap_exists_config_define("NO_DETACH");
+        foreground = ap_exists_config_define("FOREGROUND");
+    }
+
+    /* sigh, want this only the second time around */
+    if (restart_num++ == 1) {
+        is_graceful = 0;
+
+        if (!one_process && !foreground) {
+            rv = apr_proc_detach(no_detach ? APR_PROC_DETACH_FOREGROUND
+                                           : APR_PROC_DETACH_DAEMONIZE);
+            if (rv != APR_SUCCESS) {
+                ap_log_error(APLOG_MARK, APLOG_CRIT, rv, NULL,
+                             "apr_proc_detach failed");
+                return HTTP_INTERNAL_SERVER_ERROR;
+            }
+        }
+        parent_pid = ap_my_pid = getpid();
+    }
+
+    unixd_pre_config(ptemp);
+    ap_listen_pre_config();
+    ap_daemons_to_start = DEFAULT_START_DAEMON;
+    min_spare_threads = DEFAULT_MIN_FREE_DAEMON * DEFAULT_THREADS_PER_CHILD;
+    max_spare_threads = DEFAULT_MAX_FREE_DAEMON * DEFAULT_THREADS_PER_CHILD;
+    ap_daemons_limit = server_limit;
+    ap_threads_per_child = DEFAULT_THREADS_PER_CHILD;
+    ap_pid_fname = DEFAULT_PIDLOG;
+    ap_lock_fname = DEFAULT_LOCKFILE;
+    ap_max_requests_per_child = DEFAULT_MAX_REQUESTS_PER_CHILD;
+    ap_extended_status = 0;
+#ifdef AP_MPM_WANT_SET_MAX_MEM_FREE
+	ap_max_mem_free = APR_ALLOCATOR_MAX_FREE_UNLIMITED;
+#endif
+
+    apr_cpystrn(ap_coredump_dir, ap_server_root, sizeof(ap_coredump_dir));
+
+    return OK;
+}
+
+static void leader_hooks(apr_pool_t *p)
+{
+    /* The leader open_logs phase must run before the core's, or stderr
+     * will be redirected to a file, and the messages won't print to the
+     * console.
+     */
+    static const char *const aszSucc[] = {"core.c", NULL};
+    one_process = 0;
+
+    ap_hook_open_logs(leader_open_logs, NULL, aszSucc, APR_HOOK_MIDDLE);
+    /* we need to set the MPM state before other pre-config hooks use MPM query
+     * to retrieve it, so register as REALLY_FIRST
+     */
+    ap_hook_pre_config(leader_pre_config, NULL, NULL, APR_HOOK_REALLY_FIRST);
+}
+
+static const char *set_daemons_to_start(cmd_parms *cmd, void *dummy,
+                                        const char *arg) 
+{
+    const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
+    if (err != NULL) {
+        return err;
+    }
+
+    ap_daemons_to_start = atoi(arg);
+    return NULL;
+}
+
+static const char *set_min_spare_threads(cmd_parms *cmd, void *dummy,
+                                         const char *arg)
+{
+    const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
+    if (err != NULL) {
+        return err;
+    }
+
+    min_spare_threads = atoi(arg);
+    if (min_spare_threads <= 0) {
+       ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, 
+                    "WARNING: detected MinSpareThreads set to non-positive.");
+       ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, 
+                    "Resetting to 1 to avoid almost certain Apache failure.");
+       ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, 
+                    "Please read the documentation.");
+       min_spare_threads = 1;
+    }
+       
+    return NULL;
+}
+
+static const char *set_max_spare_threads(cmd_parms *cmd, void *dummy,
+                                         const char *arg)
+{
+    const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
+    if (err != NULL) {
+        return err;
+    }
+
+    max_spare_threads = atoi(arg);
+    return NULL;
+}
+
+static const char *set_max_clients (cmd_parms *cmd, void *dummy,
+                                     const char *arg) 
+{
+    int max_clients;
+    const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
+    if (err != NULL) {
+        return err;
+    }
+
+    /* It is ok to use ap_threads_per_child here because we are
+     * sure that it gets set before MaxClients in the pre_config stage. */
+    max_clients = atoi(arg);
+    if (max_clients < ap_threads_per_child) {
+       ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, 
+                    "WARNING: MaxClients (%d) must be at least as large",
+                    max_clients);
+       ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, 
+                    " large as ThreadsPerChild (%d). Automatically",
+                    ap_threads_per_child);
+       ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, 
+                    " increasing MaxClients to %d.",
+                    ap_threads_per_child);
+       max_clients = ap_threads_per_child;
+    }
+    ap_daemons_limit = max_clients / ap_threads_per_child;
+    if ((max_clients > 0) && (max_clients % ap_threads_per_child)) {
+       ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, 
+                    "WARNING: MaxClients (%d) is not an integer multiple",
+                    max_clients);
+       ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, 
+                    " of ThreadsPerChild (%d), lowering MaxClients to %d",
+                    ap_threads_per_child,
+                    ap_daemons_limit * ap_threads_per_child);
+       ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, 
+                    " for a maximum of %d child processes,",
+                    ap_daemons_limit);
+       max_clients = ap_daemons_limit * ap_threads_per_child; 
+    }
+    if (ap_daemons_limit > server_limit) {
+       ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, 
+                    "WARNING: MaxClients of %d would require %d servers,",
+                    max_clients, ap_daemons_limit);
+       ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, 
+                    " and would exceed the ServerLimit value of %d.",
+                    server_limit);
+       ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, 
+                    " Automatically lowering MaxClients to %d.  To increase,",
+                    server_limit * ap_threads_per_child);
+       ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, 
+                    " please see the ServerLimit directive.");
+       ap_daemons_limit = server_limit;
+    } 
+    else if (ap_daemons_limit < 1) {
+        ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, 
+                     "WARNING: Require MaxClients > 0, setting to 1");
+        ap_daemons_limit = 1;
+    }
+    return NULL;
+}
+
+static const char *set_threads_per_child (cmd_parms *cmd, void *dummy,
+                                          const char *arg) 
+{
+    const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
+    if (err != NULL) {
+        return err;
+    }
+
+    ap_threads_per_child = atoi(arg);
+    if (ap_threads_per_child > thread_limit) {
+        ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, 
+                     "WARNING: ThreadsPerChild of %d exceeds ThreadLimit "
+                     "value of %d", ap_threads_per_child,
+                     thread_limit);
+        ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, 
+                     "threads, lowering ThreadsPerChild to %d. To increase, please"
+                     " see the", thread_limit);
+        ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, 
+                     " ThreadLimit directive.");
+        ap_threads_per_child = thread_limit;
+    }
+    else if (ap_threads_per_child < 1) {
+        ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, 
+                     "WARNING: Require ThreadsPerChild > 0, setting to 1");
+        ap_threads_per_child = 1;
+    }
+    return NULL;
+}
+
+static const char *set_server_limit (cmd_parms *cmd, void *dummy, const char *arg) 
+{
+    int tmp_server_limit;
+    
+    const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
+    if (err != NULL) {
+        return err;
+    }
+
+    tmp_server_limit = atoi(arg);
+    /* you cannot change ServerLimit across a restart; ignore
+     * any such attempts
+     */
+    if (first_server_limit &&
+        tmp_server_limit != server_limit) {
+        /* how do we log a message?  the error log is a bit bucket at this
+         * point; we'll just have to set a flag so that ap_mpm_run()
+         * logs a warning later
+         */
+        changed_limit_at_restart = 1;
+        return NULL;
+    }
+    server_limit = tmp_server_limit;
+    
+    if (server_limit > MAX_SERVER_LIMIT) {
+       ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, 
+                    "WARNING: ServerLimit of %d exceeds compile time limit "
+                    "of %d servers,", server_limit, MAX_SERVER_LIMIT);
+       ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, 
+                    " lowering ServerLimit to %d.", MAX_SERVER_LIMIT);
+       server_limit = MAX_SERVER_LIMIT;
+    } 
+    else if (server_limit < 1) {
+	ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, 
+                     "WARNING: Require ServerLimit > 0, setting to 1");
+	server_limit = 1;
+    }
+    return NULL;
+}
+
+static const char *set_thread_limit (cmd_parms *cmd, void *dummy, const char *arg) 
+{
+    int tmp_thread_limit;
+    
+    const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
+    if (err != NULL) {
+        return err;
+    }
+
+    tmp_thread_limit = atoi(arg);
+    /* you cannot change ThreadLimit across a restart; ignore
+     * any such attempts
+     */
+    if (first_thread_limit &&
+        tmp_thread_limit != thread_limit) {
+        /* how do we log a message?  the error log is a bit bucket at this
+         * point; we'll just have to set a flag so that ap_mpm_run()
+         * logs a warning later
+         */
+        changed_limit_at_restart = 1;
+        return NULL;
+    }
+    thread_limit = tmp_thread_limit;
+    
+    if (thread_limit > MAX_THREAD_LIMIT) {
+       ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, 
+                    "WARNING: ThreadLimit of %d exceeds compile time limit "
+                    "of %d servers,", thread_limit, MAX_THREAD_LIMIT);
+       ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, 
+                    " lowering ThreadLimit to %d.", MAX_THREAD_LIMIT);
+       thread_limit = MAX_THREAD_LIMIT;
+    } 
+    else if (thread_limit < 1) {
+	ap_log_error(APLOG_MARK, APLOG_STARTUP, 0, NULL, 
+                     "WARNING: Require ThreadLimit > 0, setting to 1");
+	thread_limit = 1;
+    }
+    return NULL;
+}
+
+static const command_rec leader_cmds[] = {
+UNIX_DAEMON_COMMANDS,
+LISTEN_COMMANDS,
+AP_INIT_TAKE1("StartServers", set_daemons_to_start, NULL, RSRC_CONF,
+  "Number of child processes launched at server startup"),
+AP_INIT_TAKE1("MinSpareThreads", set_min_spare_threads, NULL, RSRC_CONF,
+  "Minimum number of idle children, to handle request spikes"),
+AP_INIT_TAKE1("MaxSpareThreads", set_max_spare_threads, NULL, RSRC_CONF,
+  "Maximum number of idle children"),
+AP_INIT_TAKE1("MaxClients", set_max_clients, NULL, RSRC_CONF,
+  "Maximum number of children alive at the same time"),
+AP_INIT_TAKE1("ThreadsPerChild", set_threads_per_child, NULL, RSRC_CONF,
+  "Number of threads each child creates"),
+AP_INIT_TAKE1("ServerLimit", set_server_limit, NULL, RSRC_CONF,
+  "Maximum value of MaxClients for this run of Apache"),
+AP_INIT_TAKE1("ThreadLimit", set_thread_limit, NULL, RSRC_CONF,
+  "Maximum worker threads in a server for this run of Apache"),
+{ NULL }
+};
+
+module AP_MODULE_DECLARE_DATA mpm_leader_module = {
+    MPM20_MODULE_STUFF,
+    ap_mpm_rewrite_args,        /* hook to run before apache parses args */
+    NULL,                       /* create per-directory config structure */
+    NULL,                       /* merge per-directory config structures */
+    NULL,                       /* create per-server config structure */
+    NULL,                       /* merge per-server config structures */
+    leader_cmds,                /* command apr_table_t */
+    leader_hooks                /* register_hooks */
+};
+
diff --git a/rubbos/app/httpd-2.0.64/server/mpm/experimental/leader/mpm.h b/rubbos/app/httpd-2.0.64/server/mpm/experimental/leader/mpm.h
new file mode 100644
index 00000000..1db1d1d0
--- /dev/null
+++ b/rubbos/app/httpd-2.0.64/server/mpm/experimental/leader/mpm.h
@@ -0,0 +1,51 @@
+/* Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "scoreboard.h"
+#include "unixd.h"
+
+#ifndef APACHE_MPM_LEADER_H
+#define APACHE_MPM_LEADER_H
+
+#define LEADER_MPM
+
+#define MPM_NAME "Leader-Follower"
+
+#define AP_MPM_WANT_RECLAIM_CHILD_PROCESSES
+#define AP_MPM_WANT_WAIT_OR_TIMEOUT
+#define AP_MPM_WANT_PROCESS_CHILD_STATUS
+#define AP_MPM_WANT_SET_PIDFILE
+#define AP_MPM_WANT_SET_SCOREBOARD
+#define AP_MPM_WANT_SET_LOCKFILE
+#define AP_MPM_WANT_SET_MAX_REQUESTS
+#define AP_MPM_WANT_SET_COREDUMPDIR
+#define AP_MPM_WANT_SET_ACCEPT_LOCK_MECH
+#define AP_MPM_WANT_SIGNAL_SERVER
+#define AP_MPM_WANT_SET_MAX_MEM_FREE
+#define AP_MPM_WANT_FATAL_SIGNAL_HANDLER
+#define AP_MPM_DISABLE_NAGLE_ACCEPTED_SOCK
+
+#define AP_MPM_USES_POD 1
+#define MPM_CHILD_PID(i) (ap_scoreboard_image->parent[i].pid)
+#define MPM_NOTE_CHILD_KILLED(i) (MPM_CHILD_PID(i) = 0)
+#define MPM_ACCEPT_FUNC unixd_accept
+
+extern int ap_threads_per_child;
+extern int ap_max_daemons_limit;
+extern server_rec *ap_server_conf;
+extern char ap_coredump_dir[MAX_STRING_LEN];
+
+#endif /* APACHE_MPM_LEADER_H */
diff --git a/rubbos/app/httpd-2.0.64/server/mpm/experimental/leader/mpm_default.h b/rubbos/app/httpd-2.0.64/server/mpm/experimental/leader/mpm_default.h
new file mode 100644
index 00000000..d5a33989
--- /dev/null
+++ b/rubbos/app/httpd-2.0.64/server/mpm/experimental/leader/mpm_default.h
@@ -0,0 +1,69 @@
+/* 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.
+ */
+
+#ifndef APACHE_MPM_DEFAULT_H
+#define APACHE_MPM_DEFAULT_H
+
+/* Number of servers to spawn off by default --- also, if fewer than
+ * this free when the caretaker checks, it will spawn more.
+ */
+#ifndef DEFAULT_START_DAEMON
+#define DEFAULT_START_DAEMON 3
+#endif
+
+/* Maximum number of *free* server processes --- more than this, and
+ * they will die off.
+ */
+
+#ifndef DEFAULT_MAX_FREE_DAEMON
+#define DEFAULT_MAX_FREE_DAEMON 10
+#endif
+
+/* Minimum --- fewer than this, and more will be created */
+
+#ifndef DEFAULT_MIN_FREE_DAEMON
+#define DEFAULT_MIN_FREE_DAEMON 3
+#endif
+
+#ifndef DEFAULT_THREADS_PER_CHILD
+#define DEFAULT_THREADS_PER_CHILD 25
+#endif
+
+/* File used for accept locking, when we use a file */
+#ifndef DEFAULT_LOCKFILE
+#define DEFAULT_LOCKFILE DEFAULT_REL_RUNTIMEDIR "/accept.lock"
+#endif
+
+/* Where the main/parent process's pid is logged */
+#ifndef DEFAULT_PIDLOG
+#define DEFAULT_PIDLOG DEFAULT_REL_RUNTIMEDIR "/httpd.pid"
+#endif
+
+/*
+ * Interval, in microseconds, between scoreboard maintenance.
+ */
+#ifndef SCOREBOARD_MAINTENANCE_INTERVAL
+#define SCOREBOARD_MAINTENANCE_INTERVAL 1000000
+#endif
+
+/* Number of requests to try to handle in a single process.  If <= 0,
+ * the children don't die off.
+ */
+#ifndef DEFAULT_MAX_REQUESTS_PER_CHILD
+#define DEFAULT_MAX_REQUESTS_PER_CHILD 10000
+#endif
+
+#endif /* AP_MPM_DEFAULT_H */