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From bri...@apache.org
Subject cvs commit: httpd-2.0/server/mpm/experimental/leader leader.c mpm.h
Date Thu, 11 Apr 2002 22:33:57 GMT
brianp      02/04/11 15:33:57

  Added:       server/mpm/experimental/leader leader.c mpm.h
  Log:
  Initial check-in of leader-follower MPM code, derived from worker
  
  Revision  Changes    Path
  1.1                  httpd-2.0/server/mpm/experimental/leader/leader.c
  
  Index: leader.c
  ===================================================================
  /* ====================================================================
   * The Apache Software License, Version 1.1
   *
   * Copyright (c) 2000-2002 The Apache Software Foundation.  All rights
   * reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   *
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in
   *    the documentation and/or other materials provided with the
   *    distribution.
   *
   * 3. The end-user documentation included with the redistribution,
   *    if any, must include the following acknowledgment:
   *       "This product includes software developed by the
   *        Apache Software Foundation (http://www.apache.org/)."
   *    Alternately, this acknowledgment may appear in the software itself,
   *    if and wherever such third-party acknowledgments normally appear.
   *
   * 4. The names "Apache" and "Apache Software Foundation" must
   *    not be used to endorse or promote products derived from this
   *    software without prior written permission. For written
   *    permission, please contact apache@apache.org.
   *
   * 5. Products derived from this software may not be called "Apache",
   *    nor may "Apache" appear in their name, without prior written
   *    permission of the Apache Software Foundation.
   *
   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
   * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
   * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
   * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
   * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
   * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   * ====================================================================
   *
   * This software consists of voluntary contributions made by many
   * individuals on behalf of the Apache Software Foundation.  For more
   * information on the Apache Software Foundation, please see
   * <http://www.apache.org/>.
   *
   * Portions of this software are based upon public domain software
   * originally written at the National Center for Supercomputing Applications,
   * University of Illinois, Urbana-Champaign.
   */
  
  /* 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_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 "pod.h"
  #include "mpm_common.h"
  #include "ap_listen.h"
  #include "scoreboard.h" 
  #include "mpm_default.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
   */
  
  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;
  
  /* 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
   */
  typedef struct {
      apr_thread_cond_t *cond;
      apr_thread_mutex_t *mutex;
  } worker_wakeup_info;
  
  /* Structure used to hold a stack of idle worker threads 
   */
  typedef struct {
      apr_thread_mutex_t *mutex;
      int no_listener;
      worker_wakeup_info **stack;
      apr_size_t nelts;
      apr_size_t nalloc;
  } worker_stack;
  
  static worker_stack* worker_stack_create(apr_pool_t *pool, apr_size_t max)
  {
      apr_status_t rv;
      worker_stack *stack = (worker_stack *)apr_palloc(pool, sizeof(*stack));
  
      if ((rv = apr_thread_mutex_create(&stack->mutex, APR_THREAD_MUTEX_DEFAULT,
                                        pool)) != APR_SUCCESS) {
          return NULL;
      }
      stack->no_listener = 1;
      stack->nelts = 0;
      stack->nalloc = max;
      stack->stack =
          (worker_wakeup_info **)apr_palloc(pool, stack->nalloc *
                                            sizeof(worker_wakeup_info *));
      return stack;
  }
  
  static apr_status_t worker_stack_wait(worker_stack *stack,
                                        worker_wakeup_info *wakeup)
  {
      apr_status_t rv;
      if ((rv = apr_thread_mutex_lock(stack->mutex)) != APR_SUCCESS) {
          return rv;
      }
      if (stack->no_listener) {
          /* this thread should become the new listener immediately */
          stack->no_listener = 0;
          if ((rv = apr_thread_mutex_unlock(stack->mutex)) != APR_SUCCESS) {
              return rv;
          }
          return APR_SUCCESS;
      }
      else {
          /* push this thread onto the stack of idle workers, and block
           * on the condition variable until awoken
           */
          if (stack->nelts == stack->nalloc) {
              return APR_ENOSPC;
          }
          stack->stack[stack->nelts++] = wakeup;
          if ((rv = apr_thread_mutex_unlock(stack->mutex)) != APR_SUCCESS) {
              return rv;
          }
          if ((rv = apr_thread_cond_wait(wakeup->cond, wakeup->mutex)) !=
              APR_SUCCESS) {
              return rv;
          }
          return APR_SUCCESS;
      }
  }
  
  static apr_status_t worker_stack_awaken_next(worker_stack *stack)
  {
      apr_status_t rv;
      if ((rv = apr_thread_mutex_lock(stack->mutex)) != APR_SUCCESS) {
          return rv;
      }
      if (stack->nelts) {
          worker_wakeup_info *wakeup = stack->stack[--stack->nelts];
          if ((rv = apr_thread_mutex_unlock(stack->mutex)) != APR_SUCCESS) {
              return rv;
          }
          if ((rv = apr_thread_cond_signal(wakeup->cond)) != APR_SUCCESS) {
              apr_thread_mutex_unlock(stack->mutex);
              return rv;
          }
      }
      else {
          stack->no_listener = 1;
          if ((rv = apr_thread_mutex_unlock(stack->mutex)) != 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)
  {
      int i;
      if (terminate_mode == mode) {
          return;
      }
      terminate_mode = mode;
  
      workers_may_exit = 1;
      for (i = 0; i < ap_threads_per_child; i++) {
          (void)worker_stack_awaken_next(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;
      }
      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)
  {
      if (pchild) {
          apr_pool_destroy(pchild);
      }
      exit(code);
  }
  
  /* handle all varieties of core dumping signals */
  static void sig_coredump(int sig)
  {
      apr_filepath_set(ap_coredump_dir, pconf);
      apr_signal(sig, SIG_DFL);
      if (ap_my_pid == parent_pid) {
          ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_NOTICE,
                       0, ap_server_conf,
                       "seg fault or similar nasty error detected "
                       "in the parent process");
          
          /* XXX we can probably add some rudimentary cleanup code here,
           * like getting rid of the pid file.  If any additional bad stuff
           * happens, we are protected from recursive errors taking down the
           * system since this function is no longer the signal handler   GLA
           */
      }
      kill(ap_my_pid, sig);
      /* At this point we've got sig blocked, because we're still inside
       * the signal handler.  When we leave the signal handler it will
       * be unblocked, and we'll take the signal... and coredump or whatever
       * is appropriate for this particular Unix.  In addition the parent
       * will see the real signal we received -- whereas if we called
       * abort() here, the parent would only see SIGABRT.
       */
  }
  
  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)
  {
      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)
  {
  
      if (restart_pending == 1) {
          /* Probably not an error - don't bother reporting it */
          return;
      }
      restart_pending = 1;
      is_graceful = graceful;
  }
  
  static void sig_term(int sig)
  {
      ap_start_shutdown();
  }
  
  static void restart(int sig)
  {
      ap_start_restart(sig == AP_SIG_GRACEFUL);
  }
  
  static void set_signals(void)
  {
  #ifndef NO_USE_SIGACTION
      struct sigaction sa;
  
      sigemptyset(&sa.sa_mask);
      sa.sa_flags = 0;
  
      if (!one_process) {
          sa.sa_handler = sig_coredump;
  #if defined(SA_ONESHOT)
          sa.sa_flags = SA_ONESHOT;
  #elif defined(SA_RESETHAND)
          sa.sa_flags = SA_RESETHAND;
  #endif
          if (sigaction(SIGSEGV, &sa, NULL) < 0)
              ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, 
                           "sigaction(SIGSEGV)");
  #ifdef SIGBUS
          if (sigaction(SIGBUS, &sa, NULL) < 0)
              ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, 
                           "sigaction(SIGBUS)");
  #endif
  #ifdef SIGABORT
          if (sigaction(SIGABORT, &sa, NULL) < 0)
              ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, 
                           "sigaction(SIGABORT)");
  #endif
  #ifdef SIGABRT
          if (sigaction(SIGABRT, &sa, NULL) < 0)
              ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, 
                           "sigaction(SIGABRT)");
  #endif
  #ifdef SIGILL
          if (sigaction(SIGILL, &sa, NULL) < 0)
              ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, 
                           "sigaction(SIGILL)");
  #endif
          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) {
          apr_signal(SIGSEGV, sig_coredump);
  #ifdef SIGBUS
          apr_signal(SIGBUS, sig_coredump);
  #endif /* SIGBUS */
  #ifdef SIGABORT
          apr_signal(SIGABORT, sig_coredump);
  #endif /* SIGABORT */
  #ifdef SIGABRT
          apr_signal(SIGABRT, sig_coredump);
  #endif /* SIGABRT */
  #ifdef SIGILL
          apr_signal(SIGILL, sig_coredump);
  #endif /* SIGILL */
  #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);
  
      if (csd >= FD_SETSIZE) {
          ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_WARNING, 0, NULL,
                       "new file descriptor %d is too large; you probably need "
                       "to rebuild Apache with a larger FD_SETSIZE "
                       "(currently %d)", 
                       csd, FD_SETSIZE);
          apr_socket_close(sock);
          return;
      }
  
      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 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 *worker_thread(apr_thread_t *thd, void * dummy)
  {
      proc_info * ti = dummy;
      int process_slot = ti->pid;
      int thread_slot = 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;
      worker_wakeup_info *wakeup;
      int is_listener;
  
      ap_update_child_status_from_indexes(process_slot, thread_slot, SERVER_STARTING, NULL);
  
      free(ti);
  
      apr_allocator_create(&allocator);
      apr_pool_create_ex(&ptrans, NULL, NULL, allocator);
      apr_allocator_set_owner(allocator, ptrans);
      bucket_alloc = apr_bucket_alloc_create(tpool);
  
      wakeup = (worker_wakeup_info *)apr_palloc(tpool, sizeof(*wakeup));
      if ((rv = apr_thread_cond_create(&wakeup->cond, tpool)) != APR_SUCCESS) {
          ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf,
                       "apr_thread_cond_create failed. Attempting to shutdown "
                       "process gracefully.");
          signal_threads(ST_GRACEFUL);
          goto done;
      }
      if ((rv = apr_thread_mutex_create(&wakeup->mutex, APR_THREAD_MUTEX_DEFAULT,
                                        tpool)) != APR_SUCCESS) {
          ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf,
                       "apr_thread_mutex_create failed. Attempting to shutdown "
                       "process gracefully.");
          signal_threads(ST_GRACEFUL);
          goto done;
      }
      apr_thread_mutex_lock(wakeup->mutex);
  
      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, wakeup)) !=
                  APR_SUCCESS) {
                  ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf,
                               "worker_stack_wait failed. Shutting down");
                  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, &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);
  
              /* If we were interrupted for whatever reason, just start
               * the main loop over again.
               */
              if (APR_STATUS_IS_EINTR(rv)) {
                  continue;
              }
              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--;
                  apr_socket_close(csd);  /* Debug only */
              }
          }
          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;
          }
      }
  
   done:
      dying = 1;
      ap_scoreboard_image->parent[process_slot].quiescing = 1;
      worker_stack_awaken_next(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, rv, ap_server_conf,
                       "worker_stack_create() failed");
          clean_child_exit(APEXIT_CHILDFATAL);
      }
  
      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;
  
              if (status != SERVER_GRACEFUL && status != SERVER_DEAD) {
                  continue;
              }
  
              my_info = (proc_info *)malloc(sizeof(proc_info));
              if (my_info == NULL) {
                  ap_log_error(APLOG_MARK, APLOG_ALERT, errno, ap_server_conf,
                               "malloc: out of memory");
                  clean_child_exit(APEXIT_CHILDFATAL);
              }
              my_info->pid = my_child_num;
              my_info->tid = i;
              my_info->sd = 0;
          
              /* We are creating threads right now */
              ap_update_child_status_from_indexes(my_child_num, i,
                                                  SERVER_STARTING, NULL);
              /* We let each thread update its own scoreboard entry.  This is
               * done because it lets us deal with tid better.
               */
              rv = apr_thread_create(&threads[i], thread_attr, 
                                     worker_thread, my_info, pchild);
              if (rv != APR_SUCCESS) {
                  ap_log_error(APLOG_MARK, APLOG_ALERT, rv, ap_server_conf,
                      "apr_thread_create: unable to create worker thread");
                  /* 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;
  
      ap_my_pid = getpid();
      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);
      }
  
      /* 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);
          apr_signal(SIGTERM, dummy_signal_handler);
          /* Watch for any messages from the parent over the POD */
          while (1) {
              rv = ap_mpm_pod_check(pod);
              if (rv == AP_NORESTART) {
                  /* see if termination was triggered while we slept */
                  switch(terminate_mode) {
                  case ST_GRACEFUL:
                      rv = AP_GRACEFUL;
                      break;
                  case ST_UNGRACEFUL:
                      rv = AP_RESTART;
                      break;
                  }
              }
              if (rv == AP_GRACEFUL || rv == AP_RESTART) {
                  /* make sure the start thread has finished; 
                   * signal_threads() and join_workers depend on that
                   */
                  join_start_thread(start_thread_id);
                  signal_threads(rv == AP_GRACEFUL ? ST_GRACEFUL : ST_UNGRACEFUL);
                  break;
              }
          }
  
          if (rv == AP_GRACEFUL) {
              /* 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);
          }
      }
  
      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_NOERRNO|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, TRUE);
          idle_spawn_rate = 1;
      }
      else if (idle_thread_count < min_spare_threads) {
          /* terminate the free list */
          if (free_length == 0) {
              /* only report this condition once */
              static int reported = 0;
              
              if (!reported) {
                  ap_log_error(APLOG_MARK, APLOG_NOERRNO|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_NOERRNO|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_NOERRNO|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 | APLOG_NOERRNO, 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");
          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");
              return 1;
          }
      }
  
      if (!is_graceful) {
          if (ap_run_pre_mpm(s->process->pool, SB_SHARED) != OK) {
              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_NOERRNO|APLOG_NOTICE, 0, ap_server_conf,
                  "%s configured -- resuming normal operations",
                  ap_get_server_version());
      ap_log_error(APLOG_MARK, APLOG_NOERRNO|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_NOERRNO|APLOG_DEBUG, 0, ap_server_conf,
  		"AcceptMutex: %s", ap_valid_accept_mutex_string);
  #endif
      restart_pending = shutdown_pending = 0;
  
      server_main_loop(remaining_children_to_start);
  
      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.)
           */
          ap_mpm_pod_killpg(pod, ap_daemons_limit, FALSE);
          ap_reclaim_child_processes(1);                /* Start with SIGTERM */
  
          if (!child_fatal) {
              /* cleanup pid file on normal shutdown */
              const char *pidfile = NULL;
              pidfile = ap_server_root_relative (pconf, ap_pid_fname);
              if ( pidfile != NULL && unlink(pidfile) == 0)
                  ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_INFO, 0,
                               ap_server_conf,
                               "removed PID file %s (pid=%ld)",
                               pidfile, (long)getpid());
      
              ap_log_error(APLOG_MARK, APLOG_NOERRNO|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_NOERRNO|APLOG_NOTICE, 0, ap_server_conf,
                       AP_SIG_GRACEFUL_STRING " received.  Doing graceful restart");
          /* wake up the children...time to die.  But we'll have more soon */
          ap_mpm_pod_killpg(pod, ap_daemons_limit, TRUE);
      
  
          /* This is mostly for debugging... so that we know what is still
           * gracefully dealing with existing request.
           */
          
      }
      else {
          /* Kill 'em all.  Since the child acts the same on the parents SIGTERM 
           * and a SIGHUP, we may as well use the same signal, because some user
           * pthreads are stealing signals from us left and right.
           */
          ap_mpm_pod_killpg(pod, ap_daemons_limit, FALSE);
  
          ap_reclaim_child_processes(1);                /* Start with SIGTERM */
          ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_NOTICE, 0, ap_server_conf,
                      "SIGHUP received.  Attempting to restart");
      }
  
      return 0;
  }
  
  /* This really should be a post_config hook, but the error log is already
   * redirected by that point, so we need to do this in the open_logs phase.
   */
  static int worker_open_logs(apr_pool_t *p, apr_pool_t *plog, apr_pool_t *ptemp, server_rec *s)
  {
      apr_status_t rv;
  
      pconf = p;
      ap_server_conf = s;
  
      if ((num_listensocks = ap_setup_listeners(ap_server_conf)) < 1) {
          ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_ALERT|APLOG_STARTUP, 0,
                       NULL, "no listening sockets available, shutting down");
          return DONE;
      }
  
      if (!one_process) {
          if ((rv = ap_mpm_pod_open(pconf, &pod))) {
              ap_log_error(APLOG_MARK, APLOG_CRIT|APLOG_STARTUP, rv, NULL,
                      "Could not open pipe-of-death.");
              return DONE;
          }
      }
      return OK;
  }
  
  static int worker_pre_config(apr_pool_t *pconf, apr_pool_t *plog, 
                               apr_pool_t *ptemp)
  {
      static int restart_num = 0;
      int no_detach, debug, foreground;
      ap_directive_t *pdir;
      ap_directive_t *max_clients = NULL;
      apr_status_t rv;
  
      /* 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;
  
      apr_cpystrn(ap_coredump_dir, ap_server_root, sizeof(ap_coredump_dir));
  
      return OK;
  }
  
  static void worker_hooks(apr_pool_t *p)
  {
      /* The worker open_logs phase must run before the core's, or stderr
       * will be redirected to a file, and the messages won't print to the
       * console.
       */
      static const char *const aszSucc[] = {"core.c", NULL};
      one_process = 0;
  
      ap_hook_open_logs(worker_open_logs, NULL, aszSucc, APR_HOOK_MIDDLE);
      ap_hook_pre_config(worker_pre_config, 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);
      if (min_spare_threads <= 0) {
         ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL, 
                      "WARNING: detected MinSpareThreads set to non-positive.");
         ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL, 
                      "Resetting to 1 to avoid almost certain Apache failure.");
         ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 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 | APLOG_NOERRNO, 0, NULL, 
                      "WARNING: MaxClients (%d) must be at least as large",
                      max_clients);
         ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL, 
                      " large as ThreadsPerChild (%d). Automatically",
                      ap_threads_per_child);
         ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 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 | APLOG_NOERRNO, 0, NULL, 
                      "WARNING: MaxClients (%d) is not an integer multiple",
                      max_clients);
         ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 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 | APLOG_NOERRNO, 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 | APLOG_NOERRNO, 0, NULL, 
                      "WARNING: MaxClients of %d would require %d servers,",
                      max_clients, ap_daemons_limit);
         ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL, 
                      " and would exceed the ServerLimit value of %d.",
                      server_limit);
         ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL, 
                      " Automatically lowering MaxClients to %d.  To increase,",
                      server_limit);
         ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 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 | APLOG_NOERRNO, 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 | APLOG_NOERRNO, 0, NULL, 
                       "WARNING: ThreadsPerChild of %d exceeds ThreadLimit "
                       "value of %d", ap_threads_per_child,
                       thread_limit);
          ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL, 
                       "threads, lowering ThreadsPerChild to %d. To increase, please"
                       " see the", thread_limit);
          ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL, 
                       " ThreadLimit directive.");
          ap_threads_per_child = thread_limit;
      }
      else if (ap_threads_per_child < 1) {
          ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 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 | APLOG_NOERRNO, 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 | APLOG_NOERRNO, 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 | APLOG_NOERRNO, 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 | APLOG_NOERRNO, 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 | APLOG_NOERRNO, 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 | APLOG_NOERRNO, 0, NULL, 
                       "WARNING: Require ThreadLimit > 0, setting to 1");
  	thread_limit = 1;
      }
      return NULL;
  }
  
  static const command_rec worker_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_worker_module = {
      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 */
  };
  
  
  
  
  1.1                  httpd-2.0/server/mpm/experimental/leader/mpm.h
  
  Index: mpm.h
  ===================================================================
  /* ====================================================================
   * The Apache Software License, Version 1.1
   *
   * Copyright (c) 2000-2002 The Apache Software Foundation.  All rights
   * reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   *
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in
   *    the documentation and/or other materials provided with the
   *    distribution.
   *
   * 3. The end-user documentation included with the redistribution,
   *    if any, must include the following acknowledgment:
   *       "This product includes software developed by the
   *        Apache Software Foundation (http://www.apache.org/)."
   *    Alternately, this acknowledgment may appear in the software itself,
   *    if and wherever such third-party acknowledgments normally appear.
   *
   * 4. The names "Apache" and "Apache Software Foundation" must
   *    not be used to endorse or promote products derived from this
   *    software without prior written permission. For written
   *    permission, please contact apache@apache.org.
   *
   * 5. Products derived from this software may not be called "Apache",
   *    nor may "Apache" appear in their name, without prior written
   *    permission of the Apache Software Foundation.
   *
   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
   * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
   * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
   * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
   * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
   * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   * ====================================================================
   *
   * This software consists of voluntary contributions made by many
   * individuals on behalf of the Apache Software Foundation.  For more
   * information on the Apache Software Foundation, please see
   * <http://www.apache.org/>.
   *
   * Portions of this software are based upon public domain software
   * originally written at the National Center for Supercomputing Applications,
   * University of Illinois, Urbana-Champaign.
   */
  #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_DISABLE_NAGLE_ACCEPTED_SOCK
  
  #define MPM_CHILD_PID(i) (ap_scoreboard_image->parent[i].pid)
  #define MPM_NOTE_CHILD_KILLED(i) (MPM_CHILD_PID(i) = 0)
  #define MPM_ACCEPT_FUNC unixd_accept
  
  extern int ap_threads_per_child;
  extern int ap_max_daemons_limit;
  extern server_rec *ap_server_conf;
  extern char ap_coredump_dir[MAX_STRING_LEN];
  
  #endif /* APACHE_MPM_LEADER_H */
  
  
  

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