Remove some shadowing

[apache] / server / mpm / prefork / prefork.c

/* ====================================================================
 * Copyright (c) 1995-1999 The Apache Group.  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. All advertising materials mentioning features or use of this
 *    software must display the following acknowledgment:
 *    "This product includes software developed by the Apache Group
 *    for use in the Apache HTTP server project (http://www.apache.org/)."
 *
 * 4. The names "Apache Server" and "Apache Group" 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 names without prior written
 *    permission of the Apache Group.
 *
 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the Apache Group
 *    for use in the Apache HTTP server project (http://www.apache.org/)."
 *
 * THIS SOFTWARE IS PROVIDED BY THE APACHE GROUP ``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 GROUP 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 Group and was originally based
 * on public domain software written at the National Center for
 * Supercomputing Applications, University of Illinois, Urbana-Champaign.
 * For more information on the Apache Group and the Apache HTTP server
 * project, please see <http://www.apache.org/>.
 *
 */

/*
 * httpd.c: simple http daemon for answering WWW file requests
 *
 * 
 * 03-21-93  Rob McCool wrote original code (up to NCSA HTTPd 1.3)
 * 
 * 03-06-95  blong
 *  changed server number for child-alone processes to 0 and changed name
 *   of processes
 *
 * 03-10-95  blong
 *      Added numerous speed hacks proposed by Robert S. Thau (rst@ai.mit.edu) 
 *      including set group before fork, and call gettime before to fork
 *      to set up libraries.
 *
 * 04-14-95  rst / rh
 *      Brandon's code snarfed from NCSA 1.4, but tinkered to work with the
 *      Apache server, and also to have child processes do accept() directly.
 *
 * April-July '95 rst
 *      Extensive rework for Apache.
 */

/* TODO: this is a cobbled together prefork MPM example... it should mostly
 * TODO: behave like apache-1.3... here's a short list of things I think
 * TODO: need cleaning up still:
 * TODO: - use ralf's mm stuff for the shared mem and mutexes
 * TODO: - clean up scoreboard stuff when we figure out how to do it in 2.0
 */

#define CORE_PRIVATE

#include "httpd.h"
#include "mpm_default.h"
#include "http_main.h"
#include "http_log.h"
#include "http_config.h"
#include "http_core.h"          /* for get_remote_host */
#include "http_connection.h"
#include "scoreboard.h"
#include "ap_mpm.h"
#include "unixd.h"
#include "iol_socket.h"
#include "ap_listen.h"
#ifdef USE_SHMGET_SCOREBOARD
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#endif

#ifdef HAVE_BSTRING_H
#include <bstring.h>            /* for IRIX, FD_SET calls bzero() */
#endif

/* config globals */

static int ap_max_requests_per_child=0;
static char *ap_pid_fname=NULL;
static char *ap_scoreboard_fname=NULL;
static char *ap_lock_fname;
static char *ap_server_argv0=NULL;
static int ap_daemons_to_start=0;
static int ap_daemons_min_free=0;
static int ap_daemons_max_free=0;
static int ap_daemons_limit=0;
static time_t ap_restart_time=0;
static int ap_extended_status = 0;

/*
 * The max child slot ever assigned, preserved across restarts.  Necessary
 * to deal with MaxClients changes across SIGUSR1 restarts.  We use this
 * value to optimize routines that have to scan the entire scoreboard.
 */
static int max_daemons_limit = -1;

static char ap_coredump_dir[MAX_STRING_LEN];

/* *Non*-shared http_main globals... */

static server_rec *server_conf;
static int sd;
static fd_set listenfds;
static int listenmaxfd;

/* one_process --- debugging mode variable; can be set from the command line
 * with the -X flag.  If set, this gets you the child_main loop running
 * in the process which originally started up (no detach, no make_child),
 * which is 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 HAS_OTHER_CHILD
/* used to maintain list of children which aren't part of the scoreboard */
typedef struct other_child_rec other_child_rec;
struct other_child_rec {
    other_child_rec *next;
    int pid;
    void (*maintenance) (int, void *, ap_wait_t);
    void *data;
    int write_fd;
};
static other_child_rec *other_children;
#endif

static pool *pconf;             /* Pool for config stuff */
static pool *pchild;            /* Pool for httpd child stuff */

static int my_pid;      /* it seems silly to call getpid all the time */
#ifndef MULTITHREAD
static int my_child_num;
#endif

#ifdef TPF
int tpf_child = 0;
char tpf_server_name[INETD_SERVNAME_LENGTH+1];
#endif /* TPF */

static scoreboard *ap_scoreboard_image = NULL;

#ifdef GPROF
/* 
 * change directory for gprof to plop the gmon.out file
 * configure in httpd.conf:
 * GprofDir logs/   -> $ServerRoot/logs/gmon.out
 * GprofDir logs/%  -> $ServerRoot/logs/gprof.$pid/gmon.out
 */
static void chdir_for_gprof(void)
{
    core_server_config *sconf = 
        ap_get_module_config(server_conf->module_config, &core_module);    
    char *dir = sconf->gprof_dir;

    if(dir) {
        char buf[512];
        int len = strlen(sconf->gprof_dir) - 1;
        if(*(dir + len) == '%') {
            dir[len] = '\0';
            ap_snprintf(buf, sizeof(buf), "%sgprof.%d", dir, (int)getpid());
        } 
        dir = ap_server_root_relative(pconf, buf[0] ? buf : dir);
        if(mkdir(dir, 0755) < 0 && errno != EEXIST) {
            ap_log_error(APLOG_MARK, APLOG_ERR, server_conf,
                         "gprof: error creating directory %s", dir);
        }
    }
    else {
        dir = ap_server_root_relative(pconf, "logs");
    }

    chdir(dir);
}
#else
#define chdir_for_gprof()
#endif

/* 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) {
        ap_destroy_pool(pchild);
    }
    chdir_for_gprof();
    exit(code);
}

#if defined(USE_FCNTL_SERIALIZED_ACCEPT) || defined(USE_FLOCK_SERIALIZED_ACCEPT)
static void expand_lock_fname(pool *p)
{
    /* XXXX possibly bogus cast */
    ap_lock_fname = ap_psprintf(p, "%s.%lu",
        ap_server_root_relative(p, ap_lock_fname), (unsigned long)getpid());
}
#endif

#if defined (USE_USLOCK_SERIALIZED_ACCEPT)

#include <ulocks.h>

static ulock_t uslock = NULL;

#define accept_mutex_child_init(x)

static void accept_mutex_init(pool *p)
{
    ptrdiff_t old;
    usptr_t *us;


    /* default is 8, allocate enough for all the children plus the parent */
    if ((old = usconfig(CONF_INITUSERS, HARD_SERVER_LIMIT + 1)) == -1) {
        perror("usconfig(CONF_INITUSERS)");
        exit(-1);
    }

    if ((old = usconfig(CONF_LOCKTYPE, US_NODEBUG)) == -1) {
        perror("usconfig(CONF_LOCKTYPE)");
        exit(-1);
    }
    if ((old = usconfig(CONF_ARENATYPE, US_SHAREDONLY)) == -1) {
        perror("usconfig(CONF_ARENATYPE)");
        exit(-1);
    }
    if ((us = usinit("/dev/zero")) == NULL) {
        perror("usinit");
        exit(-1);
    }

    if ((uslock = usnewlock(us)) == NULL) {
        perror("usnewlock");
        exit(-1);
    }
}

static void accept_mutex_on(void)
{
    switch (ussetlock(uslock)) {
    case 1:
        /* got lock */
        break;
    case 0:
        fprintf(stderr, "didn't get lock\n");
        clean_child_exit(APEXIT_CHILDFATAL);
    case -1:
        perror("ussetlock");
        clean_child_exit(APEXIT_CHILDFATAL);
    }
}

static void accept_mutex_off(void)
{
    if (usunsetlock(uslock) == -1) {
        perror("usunsetlock");
        clean_child_exit(APEXIT_CHILDFATAL);
    }
}

#elif defined (USE_PTHREAD_SERIALIZED_ACCEPT)

/* This code probably only works on Solaris ... but it works really fast
 * on Solaris.  Note that pthread mutexes are *NOT* released when a task
 * dies ... the task has to free it itself.  So we block signals and
 * try to be nice about releasing the mutex.
 */

#include <pthread.h>

static pthread_mutex_t *accept_mutex = (void *)(caddr_t) -1;
static int have_accept_mutex;
static sigset_t accept_block_mask;
static sigset_t accept_previous_mask;

static void accept_mutex_child_cleanup(void *foo)
{
    if (accept_mutex != (void *)(caddr_t)-1
        && have_accept_mutex) {
        pthread_mutex_unlock(accept_mutex);
    }
}

static void accept_mutex_child_init(pool *p)
{
    ap_register_cleanup(p, NULL, accept_mutex_child_cleanup, ap_null_cleanup);
}

static void accept_mutex_cleanup(void *foo)
{
    if (accept_mutex != (void *)(caddr_t)-1
        && munmap((caddr_t) accept_mutex, sizeof(*accept_mutex))) {
        perror("munmap");
    }
    accept_mutex = (void *)(caddr_t)-1;
}

static void accept_mutex_init(pool *p)
{
    pthread_mutexattr_t mattr;
    int fd;

    fd = open("/dev/zero", O_RDWR);
    if (fd == -1) {
        perror("open(/dev/zero)");
        exit(APEXIT_INIT);
    }
    accept_mutex = (pthread_mutex_t *) mmap((caddr_t) 0, sizeof(*accept_mutex),
                                 PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
    if (accept_mutex == (void *) (caddr_t) - 1) {
        perror("mmap");
        exit(APEXIT_INIT);
    }
    close(fd);
    if ((errno = pthread_mutexattr_init(&mattr))) {
        perror("pthread_mutexattr_init");
        exit(APEXIT_INIT);
    }
    if ((errno = pthread_mutexattr_setpshared(&mattr,
                                                PTHREAD_PROCESS_SHARED))) {
        perror("pthread_mutexattr_setpshared");
        exit(APEXIT_INIT);
    }
    if ((errno = pthread_mutex_init(accept_mutex, &mattr))) {
        perror("pthread_mutex_init");
        exit(APEXIT_INIT);
    }
    sigfillset(&accept_block_mask);
    sigdelset(&accept_block_mask, SIGHUP);
    sigdelset(&accept_block_mask, SIGTERM);
    sigdelset(&accept_block_mask, SIGUSR1);
    ap_register_cleanup(p, NULL, accept_mutex_cleanup, ap_null_cleanup);
}

static void accept_mutex_on(void)
{
    int err;

    if (sigprocmask(SIG_BLOCK, &accept_block_mask, &accept_previous_mask)) {
        perror("sigprocmask(SIG_BLOCK)");
        clean_child_exit(APEXIT_CHILDFATAL);
    }
    if ((err = pthread_mutex_lock(accept_mutex))) {
        errno = err;
        perror("pthread_mutex_lock");
        clean_child_exit(APEXIT_CHILDFATAL);
    }
    have_accept_mutex = 1;
}

static void accept_mutex_off(void)
{
    int err;

    if ((err = pthread_mutex_unlock(accept_mutex))) {
        errno = err;
        perror("pthread_mutex_unlock");
        clean_child_exit(APEXIT_CHILDFATAL);
    }
    /* There is a slight race condition right here... if we were to die right
     * now, we'd do another pthread_mutex_unlock.  Now, doing that would let
     * another process into the mutex.  pthread mutexes are designed to be
     * fast, as such they don't have protection for things like testing if the
     * thread owning a mutex is actually unlocking it (or even any way of
     * testing who owns the mutex).
     *
     * If we were to unset have_accept_mutex prior to releasing the mutex
     * then the race could result in the server unable to serve hits.  Doing
     * it this way means that the server can continue, but an additional
     * child might be in the critical section ... at least it's still serving
     * hits.
     */
    have_accept_mutex = 0;
    if (sigprocmask(SIG_SETMASK, &accept_previous_mask, NULL)) {
        perror("sigprocmask(SIG_SETMASK)");
        clean_child_exit(1);
    }
}

#elif defined (USE_SYSVSEM_SERIALIZED_ACCEPT)

#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/sem.h>

#ifdef NEED_UNION_SEMUN
/* it makes no sense, but this isn't defined on solaris */
union semun {
    long val;
    struct semid_ds *buf;
    ushort *array;
};

#endif

static int sem_id = -1;
static struct sembuf op_on;
static struct sembuf op_off;

/* We get a random semaphore ... the lame sysv semaphore interface
 * means we have to be sure to clean this up or else we'll leak
 * semaphores.
 */
static void accept_mutex_cleanup(void *foo)
{
    union semun ick;

    if (sem_id < 0)
        return;
    /* this is ignored anyhow */
    ick.val = 0;
    semctl(sem_id, 0, IPC_RMID, ick);
}

#define accept_mutex_child_init(x)

static void accept_mutex_init(pool *p)
{
    union semun ick;
    struct semid_ds buf;

    /* acquire the semaphore */
    sem_id = semget(IPC_PRIVATE, 1, IPC_CREAT | 0600);
    if (sem_id < 0) {
        perror("semget");
        exit(APEXIT_INIT);
    }
    ick.val = 1;
    if (semctl(sem_id, 0, SETVAL, ick) < 0) {
        perror("semctl(SETVAL)");
        exit(APEXIT_INIT);
    }
    if (!getuid()) {
        /* restrict it to use only by the appropriate user_id ... not that this
         * stops CGIs from acquiring it and dinking around with it.
         */
        buf.sem_perm.uid = unixd_config.user_id;
        buf.sem_perm.gid = unixd_config.group_id;
        buf.sem_perm.mode = 0600;
        ick.buf = &buf;
        if (semctl(sem_id, 0, IPC_SET, ick) < 0) {
            perror("semctl(IPC_SET)");
            exit(APEXIT_INIT);
        }
    }
    ap_register_cleanup(p, NULL, accept_mutex_cleanup, ap_null_cleanup);

    /* pre-initialize these */
    op_on.sem_num = 0;
    op_on.sem_op = -1;
    op_on.sem_flg = SEM_UNDO;
    op_off.sem_num = 0;
    op_off.sem_op = 1;
    op_off.sem_flg = SEM_UNDO;
}

static void accept_mutex_on(void)
{
    while (semop(sem_id, &op_on, 1) < 0) {
        if (errno != EINTR) {
            perror("accept_mutex_on");
            clean_child_exit(APEXIT_CHILDFATAL);
        }
    }
}

static void accept_mutex_off(void)
{
    while (semop(sem_id, &op_off, 1) < 0) {
        if (errno != EINTR) {
            perror("accept_mutex_off");
            clean_child_exit(APEXIT_CHILDFATAL);
        }
    }
}

#elif defined(USE_FCNTL_SERIALIZED_ACCEPT)
static struct flock lock_it;
static struct flock unlock_it;

static int lock_fd = -1;

#define accept_mutex_child_init(x)

/*
 * Initialize mutex lock.
 * Must be safe to call this on a restart.
 */
static void accept_mutex_init(pool *p)
{

    lock_it.l_whence = SEEK_SET;        /* from current point */
    lock_it.l_start = 0;                /* -"- */
    lock_it.l_len = 0;                  /* until end of file */
    lock_it.l_type = F_WRLCK;           /* set exclusive/write lock */
    lock_it.l_pid = 0;                  /* pid not actually interesting */
    unlock_it.l_whence = SEEK_SET;      /* from current point */
    unlock_it.l_start = 0;              /* -"- */
    unlock_it.l_len = 0;                /* until end of file */
    unlock_it.l_type = F_UNLCK;         /* set exclusive/write lock */
    unlock_it.l_pid = 0;                /* pid not actually interesting */

    expand_lock_fname(p);
    lock_fd = ap_popenf(p, ap_lock_fname, O_CREAT | O_WRONLY | O_EXCL, 0644);
    if (lock_fd == -1) {
        perror("open");
        fprintf(stderr, "Cannot open lock file: %s\n", ap_lock_fname);
        exit(APEXIT_INIT);
    }
    unlink(ap_lock_fname);
}

static void accept_mutex_on(void)
{
    int ret;

    while ((ret = fcntl(lock_fd, F_SETLKW, &lock_it)) < 0 && errno == EINTR) {
        /* nop */
    }

    if (ret < 0) {
        ap_log_error(APLOG_MARK, APLOG_EMERG, server_conf,
                    "fcntl: F_SETLKW: Error getting accept lock, exiting!  "
                    "Perhaps you need to use the LockFile directive to place "
                    "your lock file on a local disk!");
        clean_child_exit(APEXIT_CHILDFATAL);
    }
}

static void accept_mutex_off(void)
{
    int ret;

    while ((ret = fcntl(lock_fd, F_SETLKW, &unlock_it)) < 0 && errno == EINTR) {
        /* nop */
    }
    if (ret < 0) {
        ap_log_error(APLOG_MARK, APLOG_EMERG, server_conf,
                    "fcntl: F_SETLKW: Error freeing accept lock, exiting!  "
                    "Perhaps you need to use the LockFile directive to place "
                    "your lock file on a local disk!");
        clean_child_exit(APEXIT_CHILDFATAL);
    }
}

#elif defined(USE_FLOCK_SERIALIZED_ACCEPT)

static int lock_fd = -1;

static void accept_mutex_cleanup(void *foo)
{
    unlink(ap_lock_fname);
}

/*
 * Initialize mutex lock.
 * Done by each child at it's birth
 */
static void accept_mutex_child_init(pool *p)
{

    lock_fd = ap_popenf(p, ap_lock_fname, O_WRONLY, 0600);
    if (lock_fd == -1) {
        ap_log_error(APLOG_MARK, APLOG_EMERG, server_conf,
                    "Child cannot open lock file: %s", ap_lock_fname);
        clean_child_exit(APEXIT_CHILDINIT);
    }
}

/*
 * Initialize mutex lock.
 * Must be safe to call this on a restart.
 */
static void accept_mutex_init(pool *p)
{
    expand_lock_fname(p);
    unlink(ap_lock_fname);
    lock_fd = ap_popenf(p, ap_lock_fname, O_CREAT | O_WRONLY | O_EXCL, 0600);
    if (lock_fd == -1) {
        ap_log_error(APLOG_MARK, APLOG_EMERG, server_conf,
                    "Parent cannot open lock file: %s", ap_lock_fname);
        exit(APEXIT_INIT);
    }
    ap_register_cleanup(p, NULL, accept_mutex_cleanup, ap_null_cleanup);
}

static void accept_mutex_on(void)
{
    int ret;

    while ((ret = flock(lock_fd, LOCK_EX)) < 0 && errno == EINTR)
        continue;

    if (ret < 0) {
        ap_log_error(APLOG_MARK, APLOG_EMERG, server_conf,
                    "flock: LOCK_EX: Error getting accept lock. Exiting!");
        clean_child_exit(APEXIT_CHILDFATAL);
    }
}

static void accept_mutex_off(void)
{
    if (flock(lock_fd, LOCK_UN) < 0) {
        ap_log_error(APLOG_MARK, APLOG_EMERG, server_conf,
                    "flock: LOCK_UN: Error freeing accept lock. Exiting!");
        clean_child_exit(APEXIT_CHILDFATAL);
    }
}

#elif defined(USE_OS2SEM_SERIALIZED_ACCEPT)

static HMTX lock_sem = -1;

static void accept_mutex_cleanup(void *foo)
{
    DosReleaseMutexSem(lock_sem);
    DosCloseMutexSem(lock_sem);
}

/*
 * Initialize mutex lock.
 * Done by each child at it's birth
 */
static void accept_mutex_child_init(pool *p)
{
    int rc = DosOpenMutexSem(NULL, &lock_sem);

    if (rc != 0) {
        ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_EMERG, server_conf,
                    "Child cannot open lock semaphore, rc=%d", rc);
        clean_child_exit(APEXIT_CHILDINIT);
    } else {
        ap_register_cleanup(p, NULL, accept_mutex_cleanup, ap_null_cleanup);
    }
}

/*
 * Initialize mutex lock.
 * Must be safe to call this on a restart.
 */
static void accept_mutex_init(pool *p)
{
    int rc = DosCreateMutexSem(NULL, &lock_sem, DC_SEM_SHARED, FALSE);

    if (rc != 0) {
        ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_EMERG, server_conf,
                    "Parent cannot create lock semaphore, rc=%d", rc);
        exit(APEXIT_INIT);
    }

    ap_register_cleanup(p, NULL, accept_mutex_cleanup, ap_null_cleanup);
}

static void accept_mutex_on(void)
{
    int rc = DosRequestMutexSem(lock_sem, SEM_INDEFINITE_WAIT);

    if (rc != 0) {
        ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_EMERG, server_conf,
                    "OS2SEM: Error %d getting accept lock. Exiting!", rc);
        clean_child_exit(APEXIT_CHILDFATAL);
    }
}

static void accept_mutex_off(void)
{
    int rc = DosReleaseMutexSem(lock_sem);
    
    if (rc != 0) {
        ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_EMERG, server_conf,
                    "OS2SEM: Error %d freeing accept lock. Exiting!", rc);
        clean_child_exit(APEXIT_CHILDFATAL);
    }
}

#elif defined(USE_TPF_CORE_SERIALIZED_ACCEPT)

static int tpf_core_held;

static void accept_mutex_cleanup(void *foo)
{
    if(tpf_core_held)
        coruc(RESOURCE_KEY);
}

#define accept_mutex_init(x)

static void accept_mutex_child_init(pool *p)
{
    ap_register_cleanup(p, NULL, accept_mutex_cleanup, ap_null_cleanup);
    tpf_core_held = 0;
}

static void accept_mutex_on(void)
{
    corhc(RESOURCE_KEY);
    tpf_core_held = 1;
    ap_check_signals();
}

static void accept_mutex_off(void)
{
    coruc(RESOURCE_KEY);
    tpf_core_held = 0;
    ap_check_signals();
}

#else
/* Default --- no serialization.  Other methods *could* go here,
 * as #elifs...
 */
#if !defined(MULTITHREAD)
/* Multithreaded systems don't complete between processes for
 * the sockets. */
#define NO_SERIALIZED_ACCEPT
#define accept_mutex_child_init(x)
#define accept_mutex_init(x)
#define accept_mutex_on()
#define accept_mutex_off()
#endif
#endif

/* On some architectures it's safe to do unserialized accept()s in the single
 * Listen case.  But it's never safe to do it in the case where there's
 * multiple Listen statements.  Define SINGLE_LISTEN_UNSERIALIZED_ACCEPT
 * when it's safe in the single Listen case.
 */
#ifdef SINGLE_LISTEN_UNSERIALIZED_ACCEPT
#define SAFE_ACCEPT(stmt) do {if (ap_listeners->next) {stmt;}} while(0)
#else
#define SAFE_ACCEPT(stmt) do {stmt;} while(0)
#endif


/*****************************************************************
 * dealing with other children
 */

#ifdef HAS_OTHER_CHILD
API_EXPORT(void) ap_register_other_child(int pid,
                       void (*maintenance) (int reason, void *, ap_wait_t status),
                          void *data, int write_fd)
{
    other_child_rec *ocr;

    ocr = ap_palloc(pconf, sizeof(*ocr));
    ocr->pid = pid;
    ocr->maintenance = maintenance;
    ocr->data = data;
    ocr->write_fd = write_fd;
    ocr->next = other_children;
    other_children = ocr;
}

/* note that since this can be called by a maintenance function while we're
 * scanning the other_children list, all scanners should protect themself
 * by loading ocr->next before calling any maintenance function.
 */
API_EXPORT(void) ap_unregister_other_child(void *data)
{
    other_child_rec **pocr, *nocr;

    for (pocr = &other_children; *pocr; pocr = &(*pocr)->next) {
        if ((*pocr)->data == data) {
            nocr = (*pocr)->next;
            (*(*pocr)->maintenance) (OC_REASON_UNREGISTER, (*pocr)->data, -1);
            *pocr = nocr;
            /* XXX: um, well we've just wasted some space in pconf ? */
            return;
        }
    }
}

/* test to ensure that the write_fds are all still writable, otherwise
 * invoke the maintenance functions as appropriate */
static void probe_writable_fds(void)
{
    fd_set writable_fds;
    int fd_max;
    other_child_rec *ocr, *nocr;
    struct timeval tv;
    int rc;

    if (other_children == NULL)
        return;

    fd_max = 0;
    FD_ZERO(&writable_fds);
    do {
        for (ocr = other_children; ocr; ocr = ocr->next) {
            if (ocr->write_fd == -1)
                continue;
            FD_SET(ocr->write_fd, &writable_fds);
            if (ocr->write_fd > fd_max) {
                fd_max = ocr->write_fd;
            }
        }
        if (fd_max == 0)
            return;

        tv.tv_sec = 0;
        tv.tv_usec = 0;
        rc = ap_select(fd_max + 1, NULL, &writable_fds, NULL, &tv);
    } while (rc == -1 && errno == EINTR);

    if (rc == -1) {
        /* XXX: uhh this could be really bad, we could have a bad file
         * descriptor due to a bug in one of the maintenance routines */
        ap_log_unixerr("probe_writable_fds", "select",
                    "could not probe writable fds", server_conf);
        return;
    }
    if (rc == 0)
        return;

    for (ocr = other_children; ocr; ocr = nocr) {
        nocr = ocr->next;
        if (ocr->write_fd == -1)
            continue;
        if (FD_ISSET(ocr->write_fd, &writable_fds))
            continue;
        (*ocr->maintenance) (OC_REASON_UNWRITABLE, ocr->data, -1);
    }
}

/* possibly reap an other_child, return 0 if yes, -1 if not */
static int reap_other_child(int pid, ap_wait_t status)
{
    other_child_rec *ocr, *nocr;

    for (ocr = other_children; ocr; ocr = nocr) {
        nocr = ocr->next;
        if (ocr->pid != pid)
            continue;
        ocr->pid = -1;
        (*ocr->maintenance) (OC_REASON_DEATH, ocr->data, status);
        return 0;
    }
    return -1;
}
#endif

/*****************************************************************
 *
 * Dealing with the scoreboard... a lot of these variables are global
 * only to avoid getting clobbered by the longjmp() that happens when
 * a hard timeout expires...
 *
 * We begin with routines which deal with the file itself... 
 */

#if defined(USE_OS2_SCOREBOARD)

/* The next two routines are used to access shared memory under OS/2.  */
/* This requires EMX v09c to be installed.                           */

caddr_t create_shared_heap(const char *name, size_t size)
{
    ULONG rc;
    void *mem;
    Heap_t h;

    rc = DosAllocSharedMem(&mem, name, size,
                           PAG_COMMIT | PAG_READ | PAG_WRITE);
    if (rc != 0)
        return NULL;
    h = _ucreate(mem, size, !_BLOCK_CLEAN, _HEAP_REGULAR | _HEAP_SHARED,
                 NULL, NULL);
    if (h == NULL)
        DosFreeMem(mem);
    return (caddr_t) h;
}

caddr_t get_shared_heap(const char *Name)
{

    PVOID BaseAddress;          /* Pointer to the base address of
                                   the shared memory object */
    ULONG AttributeFlags;       /* Flags describing characteristics
                                   of the shared memory object */
    APIRET rc;                  /* Return code */

    /* Request read and write access to */
    /*   the shared memory object       */
    AttributeFlags = PAG_WRITE | PAG_READ;

    rc = DosGetNamedSharedMem(&BaseAddress, Name, AttributeFlags);

    if (rc != 0) {
        printf("DosGetNamedSharedMem error: return code = %ld", rc);
        return 0;
    }

    return BaseAddress;
}

static void setup_shared_mem(pool *p)
{
    caddr_t m;

    int rc;

    m = (caddr_t) create_shared_heap("\\SHAREMEM\\SCOREBOARD", SCOREBOARD_SIZE);
    if (m == 0) {
        fprintf(stderr, "%s: Could not create OS/2 Shared memory pool.\n",
                ap_server_argv0);
        exit(APEXIT_INIT);
    }

    rc = _uopen((Heap_t) m);
    if (rc != 0) {
        fprintf(stderr,
                "%s: Could not uopen() newly created OS/2 Shared memory pool.\n",
                ap_server_argv0);
    }
    ap_scoreboard_image = (scoreboard *) m;
    ap_scoreboard_image->global.running_generation = 0;
}

static void reopen_scoreboard(pool *p)
{
    caddr_t m;
    int rc;

    m = (caddr_t) get_shared_heap("\\SHAREMEM\\SCOREBOARD");
    if (m == 0) {
        fprintf(stderr, "%s: Could not find existing OS/2 Shared memory pool.\n",
                ap_server_argv0);
        exit(APEXIT_INIT);
    }

    rc = _uopen((Heap_t) m);
    ap_scoreboard_image = (scoreboard *) m;
}

#elif defined(USE_POSIX_SCOREBOARD)
#include <sys/mman.h>
/* 
 * POSIX 1003.4 style
 *
 * Note 1: 
 * As of version 4.23A, shared memory in QNX must reside under /dev/shmem,
 * where no subdirectories allowed.
 *
 * POSIX shm_open() and shm_unlink() will take care about this issue,
 * but to avoid confusion, I suggest to redefine scoreboard file name
 * in httpd.conf to cut "logs/" from it. With default setup actual name
 * will be "/dev/shmem/logs.apache_status". 
 * 
 * If something went wrong and Apache did not unlinked this object upon
 * exit, you can remove it manually, using "rm -f" command.
 * 
 * Note 2:
 * <sys/mman.h> in QNX defines MAP_ANON, but current implementation 
 * does NOT support BSD style anonymous mapping. So, the order of 
 * conditional compilation is important: 
 * this #ifdef section must be ABOVE the next one (BSD style).
 *
 * I tested this stuff and it works fine for me, but if it provides 
 * trouble for you, just comment out USE_MMAP_SCOREBOARD in QNX section
 * of ap_config.h
 *
 * June 5, 1997, 
 * Igor N. Kovalenko -- infoh@mail.wplus.net
 */

static void cleanup_shared_mem(void *d)
{
    shm_unlink(ap_scoreboard_fname);
}

static void setup_shared_mem(pool *p)
{
    char buf[512];
    caddr_t m;
    int fd;

    fd = shm_open(ap_scoreboard_fname, O_RDWR | O_CREAT, S_IRUSR | S_IWUSR);
    if (fd == -1) {
        ap_snprintf(buf, sizeof(buf), "%s: could not open(create) scoreboard",
                    ap_server_argv0);
        perror(buf);
        exit(APEXIT_INIT);
    }
    if (ltrunc(fd, (off_t) SCOREBOARD_SIZE, SEEK_SET) == -1) {
        ap_snprintf(buf, sizeof(buf), "%s: could not ltrunc scoreboard",
                    ap_server_argv0);
        perror(buf);
        shm_unlink(ap_scoreboard_fname);
        exit(APEXIT_INIT);
    }
    if ((m = (caddr_t) mmap((caddr_t) 0,
                            (size_t) SCOREBOARD_SIZE, PROT_READ | PROT_WRITE,
                            MAP_SHARED, fd, (off_t) 0)) == (caddr_t) - 1) {
        ap_snprintf(buf, sizeof(buf), "%s: cannot mmap scoreboard",
                    ap_server_argv0);
        perror(buf);
        shm_unlink(ap_scoreboard_fname);
        exit(APEXIT_INIT);
    }
    close(fd);
    ap_register_cleanup(p, NULL, cleanup_shared_mem, ap_null_cleanup);
    ap_scoreboard_image = (scoreboard *) m;
    ap_scoreboard_image->global.running_generation = 0;
}

static void reopen_scoreboard(pool *p)
{
}

#elif defined(USE_MMAP_SCOREBOARD)

static void setup_shared_mem(pool *p)
{
    caddr_t m;

#if defined(MAP_ANON)
/* BSD style */
#ifdef CONVEXOS11
    /*
     * 9-Aug-97 - Jeff Venters (venters@convex.hp.com)
     * ConvexOS maps address space as follows:
     *   0x00000000 - 0x7fffffff : Kernel
     *   0x80000000 - 0xffffffff : User
     * Start mmapped area 1GB above start of text.
     *
     * Also, the length requires a pointer as the actual length is
     * returned (rounded up to a page boundary).
     */
    {
        unsigned len = SCOREBOARD_SIZE;

        m = mmap((caddr_t) 0xC0000000, &len,
                 PROT_READ | PROT_WRITE, MAP_ANON | MAP_SHARED, NOFD, 0);
    }
#elif defined(MAP_TMPFILE)
    {
        char mfile[] = "/tmp/apache_shmem_XXXX";
        int fd = mkstemp(mfile);
        if (fd == -1) {
            perror("open");
            fprintf(stderr, "%s: Could not open %s\n", ap_server_argv0, mfile);
            exit(APEXIT_INIT);
        }
        m = mmap((caddr_t) 0, SCOREBOARD_SIZE,
                PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
        if (m == (caddr_t) - 1) {
            perror("mmap");
            fprintf(stderr, "%s: Could not mmap %s\n", ap_server_argv0, mfile);
            exit(APEXIT_INIT);
        }
        close(fd);
        unlink(mfile);
    }
#else
    m = mmap((caddr_t) 0, SCOREBOARD_SIZE,
             PROT_READ | PROT_WRITE, MAP_ANON | MAP_SHARED, -1, 0);
#endif
    if (m == (caddr_t) - 1) {
        perror("mmap");
        fprintf(stderr, "%s: Could not mmap memory\n", ap_server_argv0);
        exit(APEXIT_INIT);
    }
#else
/* Sun style */
    int fd;

    fd = open("/dev/zero", O_RDWR);
    if (fd == -1) {
        perror("open");
        fprintf(stderr, "%s: Could not open /dev/zero\n", ap_server_argv0);
        exit(APEXIT_INIT);
    }
    m = mmap((caddr_t) 0, SCOREBOARD_SIZE,
             PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
    if (m == (caddr_t) - 1) {
        perror("mmap");
        fprintf(stderr, "%s: Could not mmap /dev/zero\n", ap_server_argv0);
        exit(APEXIT_INIT);
    }
    close(fd);
#endif
    ap_scoreboard_image = (scoreboard *) m;
    ap_scoreboard_image->global.running_generation = 0;
}

static void reopen_scoreboard(pool *p)
{
}

#elif defined(USE_SHMGET_SCOREBOARD)
static key_t shmkey = IPC_PRIVATE;
static int shmid = -1;

static void setup_shared_mem(pool *p)
{
    struct shmid_ds shmbuf;
#ifdef MOVEBREAK
    char *obrk;
#endif

    if ((shmid = shmget(shmkey, SCOREBOARD_SIZE, IPC_CREAT | SHM_R | SHM_W)) == -1) {
#ifdef LINUX
        if (errno == ENOSYS) {
            ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_EMERG, server_conf,
                         "Your kernel was built without CONFIG_SYSVIPC\n"
                         "%s: Please consult the Apache FAQ for details",
                         ap_server_argv0);
        }
#endif
        ap_log_error(APLOG_MARK, APLOG_EMERG, server_conf,
                    "could not call shmget");
        exit(APEXIT_INIT);
    }

    ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_INFO, server_conf,
                "created shared memory segment #%d", shmid);

#ifdef MOVEBREAK
    /*
     * Some SysV systems place the shared segment WAY too close
     * to the dynamic memory break point (sbrk(0)). This severely
     * limits the use of malloc/sbrk in the program since sbrk will
     * refuse to move past that point.
     *
     * To get around this, we move the break point "way up there",
     * attach the segment and then move break back down. Ugly
     */
    if ((obrk = sbrk(MOVEBREAK)) == (char *) -1) {
        ap_log_error(APLOG_MARK, APLOG_ERR, server_conf,
            "sbrk() could not move break");
    }
#endif

#define BADSHMAT        ((scoreboard *)(-1))
    if ((ap_scoreboard_image = (scoreboard *) shmat(shmid, 0, 0)) == BADSHMAT) {
        ap_log_error(APLOG_MARK, APLOG_EMERG, server_conf, "shmat error");
        /*
         * We exit below, after we try to remove the segment
         */
    }
    else {                      /* only worry about permissions if we attached the segment */
        if (shmctl(shmid, IPC_STAT, &shmbuf) != 0) {
            ap_log_error(APLOG_MARK, APLOG_ERR, server_conf,
                "shmctl() could not stat segment #%d", shmid);
        }
        else {
            shmbuf.shm_perm.uid = unixd_config.user_id;
            shmbuf.shm_perm.gid = unixd_config.group_id;
            if (shmctl(shmid, IPC_SET, &shmbuf) != 0) {
                ap_log_error(APLOG_MARK, APLOG_ERR, server_conf,
                    "shmctl() could not set segment #%d", shmid);
            }
        }
    }
    /*
     * We must avoid leaving segments in the kernel's
     * (small) tables.
     */
    if (shmctl(shmid, IPC_RMID, NULL) != 0) {
        ap_log_error(APLOG_MARK, APLOG_WARNING, server_conf,
                "shmctl: IPC_RMID: could not remove shared memory segment #%d",
                shmid);
    }
    if (ap_scoreboard_image == BADSHMAT)        /* now bailout */
        exit(APEXIT_INIT);

#ifdef MOVEBREAK
    if (obrk == (char *) -1)
        return;                 /* nothing else to do */
    if (sbrk(-(MOVEBREAK)) == (char *) -1) {
        ap_log_error(APLOG_MARK, APLOG_ERR, server_conf,
            "sbrk() could not move break back");
    }
#endif
    ap_scoreboard_image->global.running_generation = 0;
}

static void reopen_scoreboard(pool *p)
{
}

#elif defined(USE_TPF_SCOREBOARD)

static void cleanup_scoreboard_heap()
{
    int rv;
    rv = rsysc(ap_scoreboard_image, SCOREBOARD_FRAMES, SCOREBOARD_NAME);
    if(rv == RSYSC_ERROR) {
        ap_log_error(APLOG_MARK, APLOG_ERR, server_conf,
            "rsysc() could not release scoreboard system heap");
    }
}

static void setup_shared_mem(pool *p)
{
    cinfc(CINFC_WRITE, CINFC_CMMCTK2);
    ap_scoreboard_image = (scoreboard *) gsysc(SCOREBOARD_FRAMES, SCOREBOARD_NAME);

    if (!ap_scoreboard_image) {
        fprintf(stderr, "httpd: Could not create scoreboard system heap storage.\n");
        exit(APEXIT_INIT);
    }

    ap_register_cleanup(p, NULL, cleanup_scoreboard_heap, ap_null_cleanup);
    ap_scoreboard_image->global.running_generation = 0;
}

static void reopen_scoreboard(pool *p)
{
    cinfc(CINFC_WRITE, CINFC_CMMCTK2);
}

#else
#define SCOREBOARD_FILE
static scoreboard _scoreboard_image;
static int scoreboard_fd = -1;

/* XXX: things are seriously screwed if we ever have to do a partial
 * read or write ... we could get a corrupted scoreboard
 */
static int force_write(int fd, void *buffer, int bufsz)
{
    int rv, orig_sz = bufsz;

    do {
        rv = write(fd, buffer, bufsz);
        if (rv > 0) {
            buffer = (char *) buffer + rv;
            bufsz -= rv;
        }
    } while ((rv > 0 && bufsz > 0) || (rv == -1 && errno == EINTR));

    return rv < 0 ? rv : orig_sz - bufsz;
}

static int force_read(int fd, void *buffer, int bufsz)
{
    int rv, orig_sz = bufsz;

    do {
        rv = read(fd, buffer, bufsz);
        if (rv > 0) {
            buffer = (char *) buffer + rv;
            bufsz -= rv;
        }
    } while ((rv > 0 && bufsz > 0) || (rv == -1 && errno == EINTR));

    return rv < 0 ? rv : orig_sz - bufsz;
}

static void cleanup_scoreboard_file(void *foo)
{
    unlink(ap_scoreboard_fname);
}

void reopen_scoreboard(pool *p)
{
    if (scoreboard_fd != -1)
        ap_pclosef(p, scoreboard_fd);

#ifdef TPF
    ap_scoreboard_fname = ap_server_root_relative(p, ap_scoreboard_fname);
#endif /* TPF */
    scoreboard_fd = ap_popenf(p, ap_scoreboard_fname, O_CREAT | O_BINARY | O_RDWR, 0666);
    if (scoreboard_fd == -1) {
        perror(ap_scoreboard_fname);
        fprintf(stderr, "Cannot open scoreboard file:\n");
        clean_child_exit(1);
    }
}
#endif

/* Called by parent process */
static void reinit_scoreboard(pool *p)
{
    int running_gen = 0;
    if (ap_scoreboard_image)
        running_gen = ap_scoreboard_image->global.running_generation;

#ifndef SCOREBOARD_FILE
    if (ap_scoreboard_image == NULL) {
        setup_shared_mem(p);
    }
    memset(ap_scoreboard_image, 0, SCOREBOARD_SIZE);
    ap_scoreboard_image->global.running_generation = running_gen;
#else
    ap_scoreboard_image = &_scoreboard_image;
    ap_scoreboard_fname = ap_server_root_relative(p, ap_scoreboard_fname);

    scoreboard_fd = ap_popenf(p, ap_scoreboard_fname, O_CREAT | O_BINARY | O_RDWR, 0644);
    if (scoreboard_fd == -1) {
        perror(ap_scoreboard_fname);
        fprintf(stderr, "Cannot open scoreboard file:\n");
        exit(APEXIT_INIT);
    }
    ap_register_cleanup(p, NULL, cleanup_scoreboard_file, ap_null_cleanup);

    memset((char *) ap_scoreboard_image, 0, sizeof(*ap_scoreboard_image));
    ap_scoreboard_image->global.running_generation = running_gen;
    force_write(scoreboard_fd, ap_scoreboard_image, sizeof(*ap_scoreboard_image));
#endif
}

/* Routines called to deal with the scoreboard image
 * --- note that we do *not* need write locks, since update_child_status
 * only updates a *single* record in place, and only one process writes to
 * a given scoreboard slot at a time (either the child process owning that
 * slot, or the parent, noting that the child has died).
 *
 * As a final note --- setting the score entry to getpid() is always safe,
 * since when the parent is writing an entry, it's only noting SERVER_DEAD
 * anyway.
 */

ap_inline void ap_sync_scoreboard_image(void)
{
#ifdef SCOREBOARD_FILE
    lseek(scoreboard_fd, 0L, 0);
    force_read(scoreboard_fd, ap_scoreboard_image, sizeof(*ap_scoreboard_image));
#endif
}

API_EXPORT(int) ap_exists_scoreboard_image(void)
{
    return (ap_scoreboard_image ? 1 : 0);
}

static ap_inline void put_scoreboard_info(int child_num,
                                       short_score *new_score_rec)
{
#ifdef SCOREBOARD_FILE
    lseek(scoreboard_fd, (long) child_num * sizeof(short_score), 0);
    force_write(scoreboard_fd, new_score_rec, sizeof(short_score));
#endif
}

int ap_update_child_status(int child_num, int status, request_rec *r)
{
    int old_status;
    short_score *ss;

    if (child_num < 0)
        return -1;

    ap_check_signals();

    ap_sync_scoreboard_image();
    ss = &ap_scoreboard_image->servers[child_num];
    old_status = ss->status;
    ss->status = status;

    if (ap_extended_status) {
        if (status == SERVER_READY || status == SERVER_DEAD) {
            /*
             * Reset individual counters
             */
            if (status == SERVER_DEAD) {
                ss->my_access_count = 0L;
                ss->my_bytes_served = 0L;
            }
            ss->conn_count = (unsigned short) 0;
            ss->conn_bytes = (unsigned long) 0;
        }
        if (r) {
            conn_rec *c = r->connection;
            ap_cpystrn(ss->client, ap_get_remote_host(c, r->per_dir_config,
                                  REMOTE_NOLOOKUP), sizeof(ss->client));
            if (r->the_request == NULL) {
                    ap_cpystrn(ss->request, "NULL", sizeof(ss->request));
            } else if (r->parsed_uri.password == NULL) {
                    ap_cpystrn(ss->request, r->the_request, sizeof(ss->request));
            } else {
                /* Don't reveal the password in the server-status view */
                    ap_cpystrn(ss->request, ap_pstrcat(r->pool, r->method, " ",
                                               ap_unparse_uri_components(r->pool, &r->parsed_uri, UNP_OMITPASSWORD),
                                               r->assbackwards ? NULL : " ", r->protocol, NULL),
                                       sizeof(ss->request));
            }
            ss->vhostrec =  r->server;
        }
    }
    if (status == SERVER_STARTING && r == NULL) {
        /* clean up the slot's vhostrec pointer (maybe re-used)
         * and mark the slot as belonging to a new generation.
         */
        ss->vhostrec = NULL;
        ap_scoreboard_image->parent[child_num].generation = ap_my_generation;
#ifdef SCOREBOARD_FILE
        lseek(scoreboard_fd, XtOffsetOf(scoreboard, parent[child_num]), 0);
        force_write(scoreboard_fd, &ap_scoreboard_image->parent[child_num],
            sizeof(parent_score));
#endif
    }
    put_scoreboard_info(child_num, ss);

    return old_status;
}

static void update_scoreboard_global(void)
{
#ifdef SCOREBOARD_FILE
    lseek(scoreboard_fd,
          (char *) &ap_scoreboard_image->global -(char *) ap_scoreboard_image, 0);
    force_write(scoreboard_fd, &ap_scoreboard_image->global,
                sizeof ap_scoreboard_image->global);
#endif
}

void ap_time_process_request(int child_num, int status)
{
    short_score *ss;
#if defined(NO_GETTIMEOFDAY) && !defined(NO_TIMES)
    struct tms tms_blk;
#endif

    if (child_num < 0)
        return;

    ap_sync_scoreboard_image();
    ss = &ap_scoreboard_image->servers[child_num];

    if (status == START_PREQUEST) {
#if defined(NO_GETTIMEOFDAY)
#ifndef NO_TIMES
        if ((ss->start_time = times(&tms_blk)) == -1)
#endif /* NO_TIMES */
            ss->start_time = (clock_t) 0;
#else
        if (gettimeofday(&ss->start_time, (struct timezone *) 0) < 0)
            ss->start_time.tv_sec =
                ss->start_time.tv_usec = 0L;
#endif
    }
    else if (status == STOP_PREQUEST) {
#if defined(NO_GETTIMEOFDAY)
#ifndef NO_TIMES
        if ((ss->stop_time = times(&tms_blk)) == -1)
#endif
            ss->stop_time = ss->start_time = (clock_t) 0;
#else
        if (gettimeofday(&ss->stop_time, (struct timezone *) 0) < 0)
            ss->stop_time.tv_sec =
                ss->stop_time.tv_usec =
                ss->start_time.tv_sec =
                ss->start_time.tv_usec = 0L;
#endif

    }

    put_scoreboard_info(child_num, ss);
}

/*
static void increment_counts(int child_num, request_rec *r)
{
    long int bs = 0;
    short_score *ss;

    ap_sync_scoreboard_image();
    ss = &ap_scoreboard_image->servers[child_num];

    if (r->sent_bodyct)
        ap_bgetopt(r->connection->client, BO_BYTECT, &bs);

#ifndef NO_TIMES
    times(&ss->times);
#endif
    ss->access_count++;
    ss->my_access_count++;
    ss->conn_count++;
    ss->bytes_served += (unsigned long) bs;
    ss->my_bytes_served += (unsigned long) bs;
    ss->conn_bytes += (unsigned long) bs;

    put_scoreboard_info(child_num, ss);
}
*/

static int find_child_by_pid(int pid)
{
    int i;

    for (i = 0; i < max_daemons_limit; ++i)
        if (ap_scoreboard_image->parent[i].pid == pid)
            return i;

    return -1;
}

static void reclaim_child_processes(int terminate)
{
#ifndef MULTITHREAD
    int i, status;
    long int waittime = 1024 * 16;      /* in usecs */
    struct timeval tv;
    int waitret, tries;
    int not_dead_yet;
#ifdef HAS_OTHER_CHILD
    other_child_rec *ocr, *nocr;
#endif

    ap_sync_scoreboard_image();

    for (tries = terminate ? 4 : 1; tries <= 9; ++tries) {
        /* don't want to hold up progress any more than 
         * necessary, but we need to allow children a few moments to exit.
         * Set delay with an exponential backoff.
         */
        tv.tv_sec = waittime / 1000000;
        tv.tv_usec = waittime % 1000000;
        waittime = waittime * 4;
        ap_select(0, NULL, NULL, NULL, &tv);

        /* now see who is done */
        not_dead_yet = 0;
        for (i = 0; i < max_daemons_limit; ++i) {
            int pid = ap_scoreboard_image->parent[i].pid;

            if (pid == my_pid || pid == 0)
                continue;

            waitret = waitpid(pid, &status, WNOHANG);
            if (waitret == pid || waitret == -1) {
                ap_scoreboard_image->parent[i].pid = 0;
                continue;
            }
            ++not_dead_yet;
            switch (tries) {
            case 1:     /*  16ms */
            case 2:     /*  82ms */
                break;
            case 3:     /* 344ms */
                /* perhaps it missed the SIGHUP, lets try again */
                ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_WARNING,
                            server_conf,
                    "child process %d did not exit, sending another SIGHUP",
                            pid);
                kill(pid, SIGHUP);
                waittime = 1024 * 16;
                break;
            case 4:     /*  16ms */
            case 5:     /*  82ms */
            case 6:     /* 344ms */
                break;
            case 7:     /* 1.4sec */
                /* ok, now it's being annoying */
                ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_WARNING,
                            server_conf,
                   "child process %d still did not exit, sending a SIGTERM",
                            pid);
                kill(pid, SIGTERM);
                break;
            case 8:     /*  6 sec */
                /* die child scum */
                ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_ERR, server_conf,
                   "child process %d still did not exit, sending a SIGKILL",
                            pid);
                kill(pid, SIGKILL);
                break;
            case 9:     /* 14 sec */
                /* gave it our best shot, but alas...  If this really 
                 * is a child we are trying to kill and it really hasn't
                 * exited, we will likely fail to bind to the port
                 * after the restart.
                 */
                ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_ERR, server_conf,
                            "could not make child process %d exit, "
                            "attempting to continue anyway", pid);
                break;
            }
        }
#ifdef HAS_OTHER_CHILD
        for (ocr = other_children; ocr; ocr = nocr) {
            nocr = ocr->next;
            if (ocr->pid == -1)
                continue;

            waitret = waitpid(ocr->pid, &status, WNOHANG);
            if (waitret == ocr->pid) {
                ocr->pid = -1;
                (*ocr->maintenance) (OC_REASON_DEATH, ocr->data, status);
            }
            else if (waitret == 0) {
                (*ocr->maintenance) (OC_REASON_RESTART, ocr->data, -1);
                ++not_dead_yet;
            }
            else if (waitret == -1) {
                /* uh what the heck? they didn't call unregister? */
                ocr->pid = -1;
                (*ocr->maintenance) (OC_REASON_LOST, ocr->data, -1);
            }
        }
#endif
        if (!not_dead_yet) {
            /* nothing left to wait for */
            break;
        }
    }
#endif /* ndef MULTITHREAD */
}


#if defined(NEED_WAITPID)
/*
   Systems without a real waitpid sometimes lose a child's exit while waiting
   for another.  Search through the scoreboard for missing children.
 */
int reap_children(ap_wait_t *status)
{
    int n, pid;

    for (n = 0; n < max_daemons_limit; ++n) {
        ap_sync_scoreboard_image();
        if (ap_scoreboard_image->servers[n].status != SERVER_DEAD &&
                kill((pid = ap_scoreboard_image->parent[n].pid), 0) == -1) {
            ap_update_child_status(n, SERVER_DEAD, NULL);
            /* just mark it as having a successful exit status */
            bzero((char *) status, sizeof(ap_wait_t));
            return(pid);
        }
    }
    return 0;
}
#endif

/* Finally, this routine is used by the caretaker process to wait for
 * a while...
 */

/* number of calls to wait_or_timeout between writable probes */
#ifndef INTERVAL_OF_WRITABLE_PROBES
#define INTERVAL_OF_WRITABLE_PROBES 10
#endif
static int wait_or_timeout_counter;

static int wait_or_timeout(ap_wait_t *status)
{
    struct timeval tv;
    int ret;

    ++wait_or_timeout_counter;
    if (wait_or_timeout_counter == INTERVAL_OF_WRITABLE_PROBES) {
        wait_or_timeout_counter = 0;
#ifdef HAS_OTHER_CHILD
        probe_writable_fds();
#endif
    }
    ret = waitpid(-1, status, WNOHANG);
    if (ret == -1 && errno == EINTR) {
        return -1;
    }
    if (ret > 0) {
        return ret;
    }
#ifdef NEED_WAITPID
    if ((ret = reap_children(status)) > 0) {
        return ret;
    }
#endif
    tv.tv_sec = SCOREBOARD_MAINTENANCE_INTERVAL / 1000000;
    tv.tv_usec = SCOREBOARD_MAINTENANCE_INTERVAL % 1000000;
    ap_select(0, NULL, NULL, NULL, &tv);
    return -1;
}

/* handle all varieties of core dumping signals */
static void sig_coredump(int sig)
{
    chdir(ap_coredump_dir);
    signal(sig, SIG_DFL);
    kill(getpid(), 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.
     */
}

/*****************************************************************
 * Connection structures and accounting...
 */

static void just_die(int sig)
{
    clean_child_exit(0);
}

static int volatile deferred_die;
static int volatile usr1_just_die;

static void usr1_handler(int sig)
{
    if (usr1_just_die) {
        just_die(sig);
    }
    deferred_die = 1;
}

/* volatile just in case */
static int volatile shutdown_pending;
static int volatile restart_pending;
static int volatile is_graceful;
ap_generation_t volatile ap_my_generation=0;

static void sig_term(int sig)
{
    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;
}

static void restart(int sig)
{
    if (restart_pending == 1) {
        /* Probably not an error - don't bother reporting it */
        return;
    }
    restart_pending = 1;
    is_graceful = sig == SIGUSR1;
}

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, server_conf, "sigaction(SIGSEGV)");
#ifdef SIGBUS
        if (sigaction(SIGBUS, &sa, NULL) < 0)
            ap_log_error(APLOG_MARK, APLOG_WARNING, server_conf, "sigaction(SIGBUS)");
#endif
#ifdef SIGABORT
        if (sigaction(SIGABORT, &sa, NULL) < 0)
            ap_log_error(APLOG_MARK, APLOG_WARNING, server_conf, "sigaction(SIGABORT)");
#endif
#ifdef SIGABRT
        if (sigaction(SIGABRT, &sa, NULL) < 0)
            ap_log_error(APLOG_MARK, APLOG_WARNING, server_conf, "sigaction(SIGABRT)");
#endif
#ifdef SIGILL
        if (sigaction(SIGILL, &sa, NULL) < 0)
            ap_log_error(APLOG_MARK, APLOG_WARNING, 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, server_conf, "sigaction(SIGTERM)");
#ifdef SIGINT
    if (sigaction(SIGINT, &sa, NULL) < 0)
        ap_log_error(APLOG_MARK, APLOG_WARNING, 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, 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, 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, server_conf, "sigaction(SIGPIPE)");
#endif

    /* we want to ignore HUPs and USR1 while we're busy processing one */
    sigaddset(&sa.sa_mask, SIGHUP);
    sigaddset(&sa.sa_mask, SIGUSR1);
    sa.sa_handler = restart;
    if (sigaction(SIGHUP, &sa, NULL) < 0)
        ap_log_error(APLOG_MARK, APLOG_WARNING, server_conf, "sigaction(SIGHUP)");
    if (sigaction(SIGUSR1, &sa, NULL) < 0)
        ap_log_error(APLOG_MARK, APLOG_WARNING, server_conf, "sigaction(SIGUSR1)");
#else
    if (!one_process) {
        signal(SIGSEGV, sig_coredump);
#ifdef SIGBUS
        signal(SIGBUS, sig_coredump);
#endif /* SIGBUS */
#ifdef SIGABORT
        signal(SIGABORT, sig_coredump);
#endif /* SIGABORT */
#ifdef SIGABRT
        signal(SIGABRT, sig_coredump);
#endif /* SIGABRT */
#ifdef SIGILL
        signal(SIGILL, sig_coredump);
#endif /* SIGILL */
#ifdef SIGXCPU
        signal(SIGXCPU, SIG_DFL);
#endif /* SIGXCPU */
#ifdef SIGXFSZ
        signal(SIGXFSZ, SIG_DFL);
#endif /* SIGXFSZ */
    }

    signal(SIGTERM, sig_term);
#ifdef SIGHUP
    signal(SIGHUP, restart);
#endif /* SIGHUP */
#ifdef SIGUSR1
    signal(SIGUSR1, restart);
#endif /* SIGUSR1 */
#ifdef SIGPIPE
    signal(SIGPIPE, SIG_IGN);
#endif /* SIGPIPE */

#endif
}

#if defined(TCP_NODELAY) && !defined(MPE) && !defined(TPF)
static void sock_disable_nagle(int s)
{
    /* The Nagle algorithm says that we should delay sending partial
     * packets in hopes of getting more data.  We don't want to do
     * this; we are not telnet.  There are bad interactions between
     * persistent connections and Nagle's algorithm that have very severe
     * performance penalties.  (Failing to disable Nagle is not much of a
     * problem with simple HTTP.)
     *
     * In spite of these problems, failure here is not a shooting offense.
     */
    int just_say_no = 1;

    if (setsockopt(s, IPPROTO_TCP, TCP_NODELAY, (char *) &just_say_no,
                   sizeof(int)) < 0) {
        ap_log_error(APLOG_MARK, APLOG_WARNING, server_conf,
                    "setsockopt: (TCP_NODELAY)");
    }
}

#else
#define sock_disable_nagle(s)   /* NOOP */
#endif


/*****************************************************************
 * Child process main loop.
 * The following vars are static to avoid getting clobbered by longjmp();
 * they are really private to child_main.
 */

static int srv;
static int csd;
static int requests_this_child;
static fd_set main_fds;

API_EXPORT(void) ap_child_terminate(request_rec *r)
{
    r->connection->keepalive = 0;
    requests_this_child = ap_max_requests_per_child = 1;
}

int ap_graceful_stop_signalled(void)
{
    ap_sync_scoreboard_image();
    if (deferred_die ||
        ap_scoreboard_image->global.running_generation != ap_my_generation) {
        return 1;
    }
    return 0;
}

static void child_main(int child_num_arg)
{
    NET_SIZE_T clen;
    struct sockaddr sa_server;
    struct sockaddr sa_client;
    ap_listen_rec *lr;
    ap_listen_rec *last_lr;
    ap_listen_rec *first_lr;
    pool *ptrans;
    conn_rec *current_conn;
    ap_iol *iol;

    my_pid = getpid();
    csd = -1;
    my_child_num = child_num_arg;
    requests_this_child = 0;
    last_lr = NULL;

    /* Get a sub pool for global allocations in this child, so that
     * we can have cleanups occur when the child exits.
     */
    pchild = ap_make_sub_pool(pconf);

    ptrans = ap_make_sub_pool(pchild);

    /* needs to be done before we switch UIDs so we have permissions */
    reopen_scoreboard(pchild);
    SAFE_ACCEPT(accept_mutex_child_init(pchild));

    if (unixd_setup_child()) {
        clean_child_exit(APEXIT_CHILDFATAL);
    }

    ap_child_init_hook(pchild, server_conf);

    (void) ap_update_child_status(my_child_num, SERVER_READY, (request_rec *) NULL);

    signal(SIGHUP, just_die);
    signal(SIGTERM, just_die);

#ifdef OS2
/* Stop Ctrl-C/Ctrl-Break signals going to child processes */
    {
        unsigned long ulTimes;
        DosSetSignalExceptionFocus(0, &ulTimes);
    }
#endif

    while (!ap_graceful_stop_signalled()) {
        BUFF *conn_io;

        /* Prepare to receive a SIGUSR1 due to graceful restart so that
         * we can exit cleanly.
         */
        usr1_just_die = 1;
        signal(SIGUSR1, usr1_handler);

        /*
         * (Re)initialize this child to a pre-connection state.
         */

        current_conn = NULL;

        ap_clear_pool(ptrans);

        if ((ap_max_requests_per_child > 0
             && requests_this_child++ >= ap_max_requests_per_child)) {
            clean_child_exit(0);
        }

        (void) ap_update_child_status(my_child_num, SERVER_READY, (request_rec *) NULL);

        /*
         * Wait for an acceptable connection to arrive.
         */

        /* Lock around "accept", if necessary */
        SAFE_ACCEPT(accept_mutex_on());

        for (;;) {
            if (ap_listeners->next) {
                /* more than one socket */
                memcpy(&main_fds, &listenfds, sizeof(fd_set));
                srv = ap_select(listenmaxfd + 1, &main_fds, NULL, NULL, NULL);

                if (srv < 0 && errno != EINTR) {
                    /* Single Unix documents select as returning errnos
                     * EBADF, EINTR, and EINVAL... and in none of those
                     * cases does it make sense to continue.  In fact
                     * on Linux 2.0.x we seem to end up with EFAULT
                     * occasionally, and we'd loop forever due to it.
                     */
                    ap_log_error(APLOG_MARK, APLOG_ERR, server_conf, "select: (listen)");
                    clean_child_exit(1);
                }

                if (srv <= 0)
                    continue;

                /* we remember the last_lr we searched last time around so that
                   we don't end up starving any particular listening socket */
                if (last_lr == NULL) {
                    lr = ap_listeners;
                }
                else {
                    lr = last_lr->next;
                    if (!lr)
                        lr = ap_listeners;
                }
                first_lr=lr;
                do {
                    if (FD_ISSET(lr->fd, &main_fds))
                        goto got_listener;
                    lr = lr->next;
                    if (!lr)
                        lr = ap_listeners;
                }
                while (lr != first_lr);
                /* FIXME: if we get here, something bad has happened, and we're
                   probably gonna spin forever.
                */
                continue;
        got_listener:
                last_lr = lr;
                sd = lr->fd;
            }
            else {
                /* only one socket, just pretend we did the other stuff */
                sd = ap_listeners->fd;
            }

            /* if we accept() something we don't want to die, so we have to
             * defer the exit
             */
            usr1_just_die = 0;
            for (;;) {
                if (deferred_die) {
                    /* we didn't get a socket, and we were told to die */
                    clean_child_exit(0);
                }
                clen = sizeof(sa_client);
                csd = ap_accept(sd, &sa_client, &clen);
                if (csd >= 0 || errno != EINTR)
                    break;
            }

            if (csd >= 0)
                break;          /* We have a socket ready for reading */
            else {

/* TODO: this accept result handling stuff should be abstracted...
 * it's already out of date between the various unix mpms
 */
                /* Our old behaviour here was to continue after accept()
                 * errors.  But this leads us into lots of troubles
                 * because most of the errors are quite fatal.  For
                 * example, EMFILE can be caused by slow descriptor
                 * leaks (say in a 3rd party module, or libc).  It's
                 * foolish for us to continue after an EMFILE.  We also
                 * seem to tickle kernel bugs on some platforms which
                 * lead to never-ending loops here.  So it seems best
                 * to just exit in most cases.
                 */
                switch (errno) {
#ifdef EPROTO
                    /* EPROTO on certain older kernels really means
                     * ECONNABORTED, so we need to ignore it for them.
                     * See discussion in new-httpd archives nh.9701
                     * search for EPROTO.
                     *
                     * Also see nh.9603, search for EPROTO:
                     * There is potentially a bug in Solaris 2.x x<6,
                     * and other boxes that implement tcp sockets in
                     * userland (i.e. on top of STREAMS).  On these
                     * systems, EPROTO can actually result in a fatal
                     * loop.  See PR#981 for example.  It's hard to
                     * handle both uses of EPROTO.
                     */
                case EPROTO:
#endif
#ifdef ECONNABORTED
                case ECONNABORTED:
#endif
                    /* Linux generates the rest of these, other tcp
                     * stacks (i.e. bsd) tend to hide them behind
                     * getsockopt() interfaces.  They occur when
                     * the net goes sour or the client disconnects
                     * after the three-way handshake has been done
                     * in the kernel but before userland has picked
                     * up the socket.
                     */
#ifdef ECONNRESET
                case ECONNRESET:
#endif
#ifdef ETIMEDOUT
                case ETIMEDOUT:
#endif
#ifdef EHOSTUNREACH
                case EHOSTUNREACH:
#endif
#ifdef ENETUNREACH
                case ENETUNREACH:
#endif
                    break;
#ifdef ENETDOWN
                case ENETDOWN:
                     /*
                      * When the network layer has been shut down, there
                      * is not much use in simply exiting: the parent
                      * would simply re-create us (and we'd fail again).
                      * Use the CHILDFATAL code to tear the server down.
                      * @@@ Martin's idea for possible improvement:
                      * A different approach would be to define
                      * a new APEXIT_NETDOWN exit code, the reception
                      * of which would make the parent shutdown all
                      * children, then idle-loop until it detected that
                      * the network is up again, and restart the children.
                      * Ben Hyde noted that temporary ENETDOWN situations
                      * occur in mobile IP.
                      */
                    ap_log_error(APLOG_MARK, APLOG_EMERG, server_conf,
                        "accept: giving up.");
                    clean_child_exit(APEXIT_CHILDFATAL);
#endif /*ENETDOWN*/

#ifdef TPF
                case EINACT:
                    ap_log_error(APLOG_MARK, APLOG_EMERG, server_conf,
                        "offload device inactive");
                    clean_child_exit(APEXIT_CHILDFATAL);
                    break;
                default:
                    ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_ERR, server_conf,
                        "select/accept error (%u)", errno);
                    clean_child_exit(APEXIT_CHILDFATAL);
#else
                default:
                    ap_log_error(APLOG_MARK, APLOG_ERR, server_conf,
                                "accept: (client socket)");
                    clean_child_exit(1);
#endif
                }
            }

            if (ap_graceful_stop_signalled()) {
                clean_child_exit(0);
            }
            usr1_just_die = 1;
        }

        SAFE_ACCEPT(accept_mutex_off());        /* unlock after "accept" */

#ifdef TPF
        if (csd == 0)                       /* 0 is invalid socket for TPF */
            continue;
#endif

        /* We've got a socket, let's at least process one request off the
         * socket before we accept a graceful restart request.  We set
         * the signal to ignore because we don't want to disturb any
         * third party code.
         */
        signal(SIGUSR1, SIG_IGN);

        /*
         * We now have a connection, so set it up with the appropriate
         * socket options, file descriptors, and read/write buffers.
         */

        clen = sizeof(sa_server);
        if (getsockname(csd, &sa_server, &clen) < 0) {
            ap_log_error(APLOG_MARK, APLOG_ERR, server_conf, "getsockname");
            close(csd);
            continue;
        }

        sock_disable_nagle(csd);

        iol = unix_attach_socket(csd);
        if (iol == NULL) {
            if (errno == EBADF) {
                ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_WARNING, NULL,
                    "filedescriptor (%u) larger than FD_SETSIZE (%u) "
                    "found, you probably need to rebuild Apache with a "
                    "larger FD_SETSIZE", csd, FD_SETSIZE);
            }
            else {
                ap_log_error(APLOG_MARK, APLOG_WARNING, NULL,
                    "error attaching to socket");
            }
            close(csd);
            continue;
        }

        (void) ap_update_child_status(my_child_num, SERVER_BUSY_READ,
                                   (request_rec *) NULL);

        conn_io = ap_bcreate(ptrans, B_RDWR);

        ap_bpush_iol(conn_io, iol);

        current_conn = ap_new_connection(ptrans, server_conf, conn_io,
                                         (struct sockaddr_in *) &sa_client,
                                         (struct sockaddr_in *) &sa_server,
                                         my_child_num);

        ap_process_connection(current_conn);
    }
}


static int make_child(server_rec *s, int slot, time_t now)
{
    int pid;

    if (slot + 1 > max_daemons_limit) {
        max_daemons_limit = slot + 1;
    }

    if (one_process) {
        signal(SIGHUP, just_die);
        signal(SIGINT, just_die);
#ifdef SIGQUIT
        signal(SIGQUIT, SIG_DFL);
#endif
        signal(SIGTERM, just_die);
        child_main(slot);
    }

    (void) ap_update_child_status(slot, SERVER_STARTING, (request_rec *) NULL);


#ifdef _OSD_POSIX
    /* BS2000 requires a "special" version of fork() before a setuid() call */
    if ((pid = os_fork(unixd_config.user_name)) == -1) {
#elif defined(TPF)
    if ((pid = os_fork(s, slot)) == -1) {
#else
    if ((pid = fork()) == -1) {
#endif
        ap_log_error(APLOG_MARK, APLOG_ERR, s, "fork: Unable to fork new process");

        /* fork didn't succeed. Fix the scoreboard or else
         * it will say SERVER_STARTING forever and ever
         */
        (void) ap_update_child_status(slot, SERVER_DEAD, (request_rec *) 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. */
        sleep(10);

        return -1;
    }

    if (!pid) {
#ifdef AIX_BIND_PROCESSOR
/* by default AIX binds to a single processor
 * this bit unbinds children which will then bind to another cpu
 */
#include <sys/processor.h>
        int status = bindprocessor(BINDPROCESS, (int)getpid(), 
                                   PROCESSOR_CLASS_ANY);
        if (status != OK) {
            ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_WARNING, server_conf,
                        "processor unbind failed %d", status);
        }
#endif
        RAISE_SIGSTOP(MAKE_CHILD);
        /* Disable the restart signal handlers and enable the just_die stuff.
         * Note that since restart() just notes that a restart has been
         * requested there's no race condition here.
         */
        signal(SIGHUP, just_die);
        signal(SIGUSR1, just_die);
        signal(SIGTERM, just_die);
        child_main(slot);
    }

    ap_scoreboard_image->parent[slot].pid = pid;
#ifdef SCOREBOARD_FILE
    lseek(scoreboard_fd, XtOffsetOf(scoreboard, parent[slot]), 0);
    force_write(scoreboard_fd, &ap_scoreboard_image->parent[slot],
                sizeof(parent_score));
#endif

    return 0;
}


/* start up a bunch of children */
static void startup_children(int number_to_start)
{
    int i;
    time_t now = time(0);

    for (i = 0; number_to_start && i < ap_daemons_limit; ++i) {
        if (ap_scoreboard_image->servers[i].status != SERVER_DEAD) {
            continue;
        }
        if (make_child(server_conf, i, now) < 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;
    int to_kill;
    int idle_count;
    short_score *ss;
    time_t now = time(0);
    int free_length;
    int free_slots[MAX_SPAWN_RATE];
    int last_non_dead;
    int total_non_dead;

    /* initialize the free_list */
    free_length = 0;

    to_kill = -1;
    idle_count = 0;
    last_non_dead = -1;
    total_non_dead = 0;

    ap_sync_scoreboard_image();
    for (i = 0; i < ap_daemons_limit; ++i) {
        int status;

        if (i >= max_daemons_limit && free_length == idle_spawn_rate)
            break;
        ss = &ap_scoreboard_image->servers[i];
        status = ss->status;
        if (status == SERVER_DEAD) {
            /* try to keep children numbers as low as possible */
            if (free_length < idle_spawn_rate) {
                free_slots[free_length] = i;
                ++free_length;
            }
        }
        else {
            /* 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) {
                ++ idle_count;
                /* always kill the highest numbered child if we have to...
                 * no really well thought out reason ... other than observing
                 * the server behaviour under linux where lower numbered children
                 * tend to service more hits (and hence are more likely to have
                 * their data in cpu caches).
                 */
                to_kill = i;
            }

            ++total_non_dead;
            last_non_dead = i;
        }
    }
    max_daemons_limit = last_non_dead + 1;
    if (idle_count > ap_daemons_max_free) {
        /* kill off one child... we use SIGUSR1 because that'll cause it to
         * shut down gracefully, in case it happened to pick up a request
         * while we were counting
         */
        kill(ap_scoreboard_image->parent[to_kill].pid, SIGUSR1);
        idle_spawn_rate = 1;
    }
    else if (idle_count < ap_daemons_min_free) {
        /* 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, server_conf,
                            "server reached MaxClients setting, consider"
                            " raising the MaxClients setting");
                reported = 1;
            }
            idle_spawn_rate = 1;
        }
        else {
            if (idle_spawn_rate >= 8) {
                ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_INFO, server_conf,
                    "server seems busy, (you may need "
                    "to increase StartServers, or Min/MaxSpareServers), "
                    "spawning %d children, there are %d idle, and "
                    "%d total children", idle_spawn_rate,
                    idle_count, total_non_dead);
            }
            for (i = 0; i < free_length; ++i) {
#ifdef TPF
        if(make_child(server_conf, free_slots[i], now) == -1) {
            if(free_length == 1) {
                shutdown_pending = 1;
                ap_log_error(APLOG_MARK, APLOG_EMERG, server_conf,
                "No active child processes: shutting down");
            }
        }
#else
                make_child(server_conf, free_slots[i], now);
#endif /* TPF */
            }
            /* 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 process_child_status(int pid, ap_wait_t status)
{
    /* Child died... if it died due to a fatal error,
        * we should simply bail out.
        */
    if ((WIFEXITED(status)) &&
        WEXITSTATUS(status) == APEXIT_CHILDFATAL) {
        ap_log_error(APLOG_MARK, APLOG_ALERT|APLOG_NOERRNO, server_conf,
                        "Child %d returned a Fatal error... \n"
                        "Apache is exiting!",
                        pid);
        exit(APEXIT_CHILDFATAL);
    }
    if (WIFSIGNALED(status)) {
        switch (WTERMSIG(status)) {
        case SIGTERM:
        case SIGHUP:
        case SIGUSR1:
        case SIGKILL:
            break;
        default:
#ifdef SYS_SIGLIST
#ifdef WCOREDUMP
            if (WCOREDUMP(status)) {
                ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_NOTICE,
                             server_conf,
                             "child pid %d exit signal %s (%d), "
                             "possible coredump in %s",
                             pid, (WTERMSIG(status) >= NumSIG) ? "" : 
                             SYS_SIGLIST[WTERMSIG(status)], WTERMSIG(status),
                             ap_coredump_dir);
            }
            else {
#endif
                ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_NOTICE,
                             server_conf,
                             "child pid %d exit signal %s (%d)", pid,
                             SYS_SIGLIST[WTERMSIG(status)], WTERMSIG(status));
#ifdef WCOREDUMP
            }
#endif
#else
            ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_NOTICE,
                         server_conf,
                         "child pid %d exit signal %d",
                         pid, WTERMSIG(status));
#endif
        }
    }
}


static int setup_listeners(pool *p, server_rec *s)
{
    ap_listen_rec *lr;

    if (ap_listen_open(p, s->port)) {
        ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_ALERT, s,
                    "no listening sockets available, shutting down");
        return -1;
    }

    listenmaxfd = -1;
    FD_ZERO(&listenfds);
    for (lr = ap_listeners; lr; lr = lr->next) {
        FD_SET(lr->fd, &listenfds);
        if (lr->fd > listenmaxfd) {
            listenmaxfd = lr->fd;
        }
    }
    return 0;
}


/*****************************************************************
 * Executive routines.
 */

int ap_mpm_run(pool *_pconf, pool *plog, server_rec *s)
{
    int remaining_children_to_start;

    pconf = _pconf;

    server_conf = s;

    ap_log_pid(pconf, ap_pid_fname);

    if (setup_listeners(pconf, s)) {
        /* XXX: hey, what's the right way for the mpm to indicate a fatal error? */
        return 1;
    }

    SAFE_ACCEPT(accept_mutex_init(pconf));
    if (!is_graceful) {
        reinit_scoreboard(pconf);
    }
#ifdef SCOREBOARD_FILE
    else {
        ap_scoreboard_fname = ap_server_root_relative(pconf, ap_scoreboard_fname);
        ap_note_cleanups_for_fd(pconf, scoreboard_fd);
    }
#endif

    set_signals();

    if (ap_daemons_max_free < ap_daemons_min_free + 1)  /* Don't thrash... */
        ap_daemons_max_free = ap_daemons_min_free + 1;

    /* 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 SIGUSR1).  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, server_conf,
                "%s configured -- resuming normal operations",
                ap_get_server_version());
    ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_INFO, server_conf,
                "Server built: %s", ap_get_server_built());
    restart_pending = shutdown_pending = 0;

    while (!restart_pending && !shutdown_pending) {
        int child_slot;
        ap_wait_t status;
        int pid = wait_or_timeout(&status);

        /* XXX: if it takes longer than 1 second for all our children
         * to start up and get into IDLE state then we may spawn an
         * extra child
         */
        if (pid >= 0) {
            process_child_status(pid, status);
            /* non-fatal death... note that it's gone in the scoreboard. */
            ap_sync_scoreboard_image();
            child_slot = find_child_by_pid(pid);
            if (child_slot >= 0) {
                (void) ap_update_child_status(child_slot, SERVER_DEAD,
                                            (request_rec *) NULL);
                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(server_conf, child_slot, time(0));
                    --remaining_children_to_start;
                }
#ifdef HAS_OTHER_CHILD
            }
            else if (reap_other_child(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, server_conf,
                            "long lost child came home! (pid %d)", 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();
#ifdef TPF
    shutdown_pending = os_check_server(tpf_server_name);
    ap_check_signals();
    sleep(1);
#endif /*TPF */
    }

    if (shutdown_pending) {
        /* Time to gracefully shut down:
         * Kill child processes, tell them to call child_exit, etc...
         */
        if (ap_killpg(getpgrp(), SIGTERM) < 0) {
            ap_log_error(APLOG_MARK, APLOG_WARNING, server_conf, "killpg SIGTERM");
        }
        reclaim_child_processes(1);             /* Start with SIGTERM */

        /* 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,
                                server_conf,
                                "removed PID file %s (pid=%ld)",
                                pidfile, (long)getpid());
        }

        ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_NOTICE, server_conf,
                    "caught SIGTERM, shutting down");
        return 1;
    }

    /* we've been told to restart */
    signal(SIGHUP, SIG_IGN);
    signal(SIGUSR1, 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;
    update_scoreboard_global();

    if (is_graceful) {
#ifndef SCOREBOARD_FILE
        int i;
#endif
        ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_NOTICE, server_conf,
                    "SIGUSR1 received.  Doing graceful restart");

        /* kill off the idle ones */
        if (ap_killpg(getpgrp(), SIGUSR1) < 0) {
            ap_log_error(APLOG_MARK, APLOG_WARNING, server_conf, "killpg SIGUSR1");
        }
#ifndef SCOREBOARD_FILE
        /* This is mostly for debugging... so that we know what is still
            * gracefully dealing with existing request.  But we can't really
            * do it if we're in a SCOREBOARD_FILE because it'll cause
            * corruption too easily.
            */
        ap_sync_scoreboard_image();
        for (i = 0; i < ap_daemons_limit; ++i) {
            if (ap_scoreboard_image->servers[i].status != SERVER_DEAD) {
                ap_scoreboard_image->servers[i].status = SERVER_GRACEFUL;
            }
        }
#endif
    }
    else {
        /* Kill 'em off */
        if (ap_killpg(getpgrp(), SIGHUP) < 0) {
            ap_log_error(APLOG_MARK, APLOG_WARNING, server_conf, "killpg SIGHUP");
        }
        reclaim_child_processes(0);             /* Not when just starting up */
        ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_NOTICE, server_conf,
                    "SIGHUP received.  Attempting to restart");
    }

    if (!is_graceful) {
        ap_restart_time = time(NULL);
    }

    return 0;
}

static void prefork_pre_config(pool *p, pool *plog, pool *ptemp)
{
    static int restart_num = 0;

    one_process = !!getenv("ONE_PROCESS");

    /* sigh, want this only the second time around */
    if (restart_num++ == 1) {
        is_graceful = 0;

        if (!one_process) {
            unixd_detach();
        }

        my_pid = getpid();
    }

    unixd_pre_config();
    ap_listen_pre_config();
    ap_daemons_to_start = DEFAULT_START_DAEMON;
    ap_daemons_min_free = DEFAULT_MIN_FREE_DAEMON;
    ap_daemons_max_free = DEFAULT_MAX_FREE_DAEMON;
    ap_daemons_limit = HARD_SERVER_LIMIT;
    ap_pid_fname = DEFAULT_PIDLOG;
    ap_scoreboard_fname = DEFAULT_SCOREBOARD;
    ap_lock_fname = DEFAULT_LOCKFILE;
    ap_max_requests_per_child = DEFAULT_MAX_REQUESTS_PER_CHILD;
    ap_extended_status = 0;

    ap_cpystrn(ap_coredump_dir, ap_server_root, sizeof(ap_coredump_dir));
}

static void prefork_hooks(void)
{
    ap_hook_pre_config(prefork_pre_config,NULL,NULL,HOOK_MIDDLE);
    INIT_SIGLIST();
#ifdef AUX3
    (void) set42sig();
#endif
    /* TODO: set one_process properly */ one_process = 0;
}

static const char *set_pidfile(cmd_parms *cmd, void *dummy, char *arg) 
{
    const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
    if (err != NULL) {
        return err;
    }

    if (cmd->server->is_virtual) {
        return "PidFile directive not allowed in <VirtualHost>";
    }
    ap_pid_fname = arg;
    return NULL;
}

static const char *set_scoreboard(cmd_parms *cmd, void *dummy, char *arg) 
{
    const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
    if (err != NULL) {
        return err;
    }

    ap_scoreboard_fname = arg;
    return NULL;
}

static const char *set_lockfile(cmd_parms *cmd, void *dummy, char *arg) 
{
    const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
    if (err != NULL) {
        return err;
    }

    ap_lock_fname = arg;
    return NULL;
}

static const char *set_daemons_to_start(cmd_parms *cmd, void *dummy, 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_free_servers(cmd_parms *cmd, void *dummy, char *arg)
{
    const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
    if (err != NULL) {
        return err;
    }

    ap_daemons_min_free = atoi(arg);
    if (ap_daemons_min_free <= 0) {
       fprintf(stderr, "WARNING: detected MinSpareServers set to non-positive.\n");
       fprintf(stderr, "Resetting to 1 to avoid almost certain Apache failure.\n");
       fprintf(stderr, "Please read the documentation.\n");
       ap_daemons_min_free = 1;
    }
       
    return NULL;
}

static const char *set_max_free_servers(cmd_parms *cmd, void *dummy, char *arg)
{
    const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
    if (err != NULL) {
        return err;
    }

    ap_daemons_max_free = atoi(arg);
    return NULL;
}

static const char *set_server_limit (cmd_parms *cmd, void *dummy, char *arg) 
{
    const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
    if (err != NULL) {
        return err;
    }

    ap_daemons_limit = atoi(arg);
    if (ap_daemons_limit > HARD_SERVER_LIMIT) {
       fprintf(stderr, "WARNING: MaxClients of %d exceeds compile time limit "
           "of %d servers,\n", ap_daemons_limit, HARD_SERVER_LIMIT);
       fprintf(stderr, " lowering MaxClients to %d.  To increase, please "
           "see the\n", HARD_SERVER_LIMIT);
       fprintf(stderr, " HARD_SERVER_LIMIT define in src/include/httpd.h.\n");
       ap_daemons_limit = HARD_SERVER_LIMIT;
    } 
    else if (ap_daemons_limit < 1) {
        fprintf(stderr, "WARNING: Require MaxClients > 0, setting to 1\n");
        ap_daemons_limit = 1;
    }
    return NULL;
}

static const char *set_max_requests(cmd_parms *cmd, void *dummy, char *arg) 
{
    const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
    if (err != NULL) {
        return err;
    }

    ap_max_requests_per_child = atoi(arg);

    return NULL;
}

static const char *set_coredumpdir (cmd_parms *cmd, void *dummy, char *arg) 
{
    struct stat finfo;
    const char *fname;
    const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
    if (err != NULL) {
        return err;
    }

    fname = ap_server_root_relative(cmd->pool, arg);
    /* ZZZ change this to the AP func FileInfo*/
    if ((stat(fname, &finfo) == -1) || !S_ISDIR(finfo.st_mode)) {
        return ap_pstrcat(cmd->pool, "CoreDumpDirectory ", fname, 
                          " does not exist or is not a directory", NULL);
    }
    ap_cpystrn(ap_coredump_dir, fname, sizeof(ap_coredump_dir));
    return NULL;
}

/* there are no threads in the prefork model, so the mutexes are
   nops. */
/* TODO: make these #defines to eliminate the function call */

struct ap_thread_mutex {
    int dummy;
};

API_EXPORT(ap_thread_mutex *) ap_thread_mutex_new(void)
{
    return malloc(sizeof(ap_thread_mutex));
}

API_EXPORT(void) ap_thread_mutex_lock(ap_thread_mutex *mtx)
{
}

API_EXPORT(void) ap_thread_mutex_unlock(ap_thread_mutex *mtx)
{
}

API_EXPORT(void) ap_thread_mutex_destroy(ap_thread_mutex *mtx)
{
    free(mtx);
}


static const command_rec prefork_cmds[] = {
UNIX_DAEMON_COMMANDS
LISTEN_COMMANDS
{ "PidFile", set_pidfile, NULL, RSRC_CONF, TAKE1,
    "A file for logging the server process ID"},
{ "ScoreBoardFile", set_scoreboard, NULL, RSRC_CONF, TAKE1,
    "A file for Apache to maintain runtime process management information"},
{ "LockFile", set_lockfile, NULL, RSRC_CONF, TAKE1,
    "The lockfile used when Apache needs to lock the accept() call"},
{ "StartServers", set_daemons_to_start, NULL, RSRC_CONF, TAKE1,
  "Number of child processes launched at server startup" },
{ "MinSpareServers", set_min_free_servers, NULL, RSRC_CONF, TAKE1,
  "Minimum number of idle children, to handle request spikes" },
{ "MaxSpareServers", set_max_free_servers, NULL, RSRC_CONF, TAKE1,
  "Maximum number of idle children" },
{ "MaxClients", set_server_limit, NULL, RSRC_CONF, TAKE1,
  "Maximum number of children alive at the same time" },
{ "MaxRequestsPerChild", set_max_requests, NULL, RSRC_CONF, TAKE1,
  "Maximum number of requests a particular child serves before dying." },
{ "CoreDumpDirectory", set_coredumpdir, NULL, RSRC_CONF, TAKE1,
  "The location of the directory Apache changes to before dumping core" },
{ NULL }
};

module MODULE_VAR_EXPORT mpm_prefork_module = {
    STANDARD20_MODULE_STUFF,
    NULL,                       /* create per-directory config structure */
    NULL,                       /* merge per-directory config structures */
    NULL,                       /* create per-server config structure */
    NULL,                       /* merge per-server config structures */
    prefork_cmds,               /* command table */
    NULL,                       /* handlers */
    prefork_hooks,              /* register hooks */
};