mpm/prefork/prefork.c

	prefork.c revision a017b39c5ddc65bd8217cb69f3dc06378da941ee
/* ====================================================================
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 2000 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Apache" and "Apache Software Foundation" must
 *    not be used to endorse or promote products derived from this
 *    software without prior written permission. For written
 *    permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache",
 *    nor may "Apache" appear in their name, without prior written
 *    permission of the Apache Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 * Portions of this software are based upon public domain software
 * originally written at the National Center for Supercomputing Applications,
 * University of Illinois, Urbana-Champaign.
 */

/*
 * 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: - clean up scoreboard stuff when we figure out how to do it in 2.0
 */

#define CORE_PRIVATE

#include "ap_config.h"
#include "apr_portable.h"
#include "apr_thread_proc.h"
#include "httpd.h"
#include "mpm_default.h"
#include "mpm_status.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 "mpm_common.h"
#include "iol_socket.h"
#include "ap_listen.h"
#include "ap_mmn.h"
#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#ifdef HAVE_SYS_WAIT_H
#include <sys/wait.h>
#endif
#ifdef HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef HAVE_NETINET_TCP_H
#include <netinet/tcp.h>    /* for TCP_NODELAY */
#endif

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

/* config globals */

static int ap_max_requests_per_child=0;
static const char *ap_pid_fname=NULL;
static ap_lock_t *accept_lock;
static const char *ap_scoreboard_fname=NULL;
static const char *ap_lock_fname;
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;
static int maintain_connection_status = 1;

/*
 * 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.
 */
int ap_max_daemons_limit = -1;
server_rec *ap_server_conf;

static char ap_coredump_dir[MAX_STRING_LEN];

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

static ap_socket_t *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;

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

int ap_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 */

API_VAR_EXPORT scoreboard *ap_scoreboard_image = NULL;
static new_scoreboard *ap_new_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(ap_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, errno, ap_server_conf,
             "gprof: error creating directory %s", dir);
    }
    }
    else {
    dir = ap_server_root_relative(pconf, "logs");
    }

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

/* XXX - I don't know if TPF will ever use this module or not, so leave
 * the ap_check_signals calls in but disable them - manoj */
#define ap_check_signals()

/* 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);
}

static void expand_lock_fname(ap_pool_t *p)
{
    /* XXXX possibly bogus cast */
    ap_lock_fname = ap_psprintf(p, "%s.%lu",
    ap_server_root_relative(p, ap_lock_fname), (unsigned long)getpid());
}

/* Initialize mutex lock.
 * Done by each child at its birth
 */
static void accept_mutex_child_init(ap_pool_t *p)
{
    ap_child_init_lock(&accept_lock, ap_lock_fname, p);
}

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

    expand_lock_fname(p);
    rv = ap_create_lock(&accept_lock, APR_MUTEX, APR_CROSS_PROCESS, ap_lock_fname, p);
    if (rv) {
    ap_log_error(APLOG_MARK, APLOG_ERR, rv, NULL, "couldn't create accept mutex");
    }
}

static void accept_mutex_on(void)
{
    ap_status_t rv = ap_lock(accept_lock);
    ap_assert(!rv);
}

static void accept_mutex_off(void)
{
    ap_status_t rv = ap_unlock(accept_lock);
    ap_assert(!rv);
}

/* 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

#if APR_HAS_SHARED_MEMORY
#include "apr_shmem.h"

static ap_shmem_t *scoreboard_shm = NULL;

static ap_status_t cleanup_shared_mem(void *d)
{
    ap_shm_free(scoreboard_shm, ap_scoreboard_image);
    ap_scoreboard_image = NULL;
    ap_shm_destroy(scoreboard_shm);
    return APR_SUCCESS;
}

static void setup_shared_mem(ap_pool_t *p)
{
    char buf[512];
    const char *fname;

    fname = ap_server_root_relative(p, ap_scoreboard_fname);
    if (ap_shm_init(&scoreboard_shm, SCOREBOARD_SIZE + NEW_SCOREBOARD_SIZE + 40, fname, p) != APR_SUCCESS) {
    ap_snprintf(buf, sizeof(buf), "%s: could not open(create) scoreboard",
            ap_server_argv0);
    perror(buf);
    exit(APEXIT_INIT);
    }
    ap_scoreboard_image = ap_shm_malloc(scoreboard_shm, SCOREBOARD_SIZE);
    ap_new_scoreboard_image = ap_shm_malloc(scoreboard_shm, NEW_SCOREBOARD_SIZE);
    if (ap_scoreboard_image == NULL) {
    ap_snprintf(buf, sizeof(buf), "%s: cannot allocate scoreboard",
            ap_server_argv0);
    perror(buf);
    ap_shm_destroy(scoreboard_shm);
    exit(APEXIT_INIT);
    }
    ap_register_cleanup(p, NULL, cleanup_shared_mem, ap_null_cleanup);
    ap_scoreboard_image->global.running_generation = 0;
}

static void reopen_scoreboard(ap_pool_t *p)
{
}
#endif

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

    if (ap_scoreboard_image == NULL) {
        setup_shared_mem(p);
    }
    memset(ap_scoreboard_image, 0, SCOREBOARD_SIZE);
    ap_scoreboard_image->global.running_generation = running_gen;
}


/* 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();

    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 (child_num < 0)
    return;

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

    if (status == START_PREQUEST) {
    ss->start_time = ap_now();
    }
    else if (status == STOP_PREQUEST) {
    ss->stop_time = ap_now();
    }

    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);

#ifdef HAVE_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(ap_proc_t *pid)
{
    int i;

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

    return -1;
}

#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 < ap_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

/* handle all varieties of core dumping signals */
static void sig_coredump(int sig)
{
    chdir(ap_coredump_dir);
    ap_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;
    if ((is_graceful = (sig == SIGUSR1))) {
        ap_kill_cleanup(pconf, NULL, cleanup_shared_mem);
    }
}

static void set_signals(void)
{
#ifndef NO_USE_SIGACTION
    struct sigaction sa;

    sigemptyset(&sa.sa_mask);
    sa.sa_flags = 0;

    if (!one_process) {
    sa.sa_handler = sig_coredump;
#if defined(SA_ONESHOT)
    sa.sa_flags = SA_ONESHOT;
#elif defined(SA_RESETHAND)
    sa.sa_flags = SA_RESETHAND;
#endif
    if (sigaction(SIGSEGV, &sa, NULL) < 0)
        ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "sigaction(SIGSEGV)");
#ifdef SIGBUS
    if (sigaction(SIGBUS, &sa, NULL) < 0)
        ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "sigaction(SIGBUS)");
#endif
#ifdef SIGABORT
    if (sigaction(SIGABORT, &sa, NULL) < 0)
        ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "sigaction(SIGABORT)");
#endif
#ifdef SIGABRT
    if (sigaction(SIGABRT, &sa, NULL) < 0)
        ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "sigaction(SIGABRT)");
#endif
#ifdef SIGILL
    if (sigaction(SIGILL, &sa, NULL) < 0)
        ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "sigaction(SIGILL)");
#endif
    sa.sa_flags = 0;
    }
    sa.sa_handler = sig_term;
    if (sigaction(SIGTERM, &sa, NULL) < 0)
    ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "sigaction(SIGTERM)");
#ifdef SIGINT
    if (sigaction(SIGINT, &sa, NULL) < 0)
        ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "sigaction(SIGINT)");
#endif
#ifdef SIGXCPU
    sa.sa_handler = SIG_DFL;
    if (sigaction(SIGXCPU, &sa, NULL) < 0)
    ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "sigaction(SIGXCPU)");
#endif
#ifdef SIGXFSZ
    sa.sa_handler = SIG_DFL;
    if (sigaction(SIGXFSZ, &sa, NULL) < 0)
    ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "sigaction(SIGXFSZ)");
#endif
#ifdef SIGPIPE
    sa.sa_handler = SIG_IGN;
    if (sigaction(SIGPIPE, &sa, NULL) < 0)
    ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "sigaction(SIGPIPE)");
#endif

    /* we want to ignore HUPs and 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, errno, ap_server_conf, "sigaction(SIGHUP)");
    if (sigaction(SIGUSR1, &sa, NULL) < 0)
    ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "sigaction(SIGUSR1)");
#else
    if (!one_process) {
    ap_signal(SIGSEGV, sig_coredump);
#ifdef SIGBUS
    ap_signal(SIGBUS, sig_coredump);
#endif /* SIGBUS */
#ifdef SIGABORT
    ap_signal(SIGABORT, sig_coredump);
#endif /* SIGABORT */
#ifdef SIGABRT
    ap_signal(SIGABRT, sig_coredump);
#endif /* SIGABRT */
#ifdef SIGILL
    ap_signal(SIGILL, sig_coredump);
#endif /* SIGILL */
#ifdef SIGXCPU
    ap_signal(SIGXCPU, SIG_DFL);
#endif /* SIGXCPU */
#ifdef SIGXFSZ
    ap_signal(SIGXFSZ, SIG_DFL);
#endif /* SIGXFSZ */
    }

    ap_signal(SIGTERM, sig_term);
#ifdef SIGHUP
    ap_signal(SIGHUP, restart);
#endif /* SIGHUP */
#ifdef SIGUSR1
    ap_signal(SIGUSR1, restart);
#endif /* SIGUSR1 */
#ifdef SIGPIPE
    ap_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, errno, ap_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 ap_socket_t *csd;
static int requests_this_child;
static fd_set main_fds;

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)
{
    ap_listen_rec *lr;
    ap_listen_rec *last_lr;
    ap_listen_rec *first_lr;
    ap_pool_t *ptrans;
    conn_rec *current_conn;
    ap_iol *iol;
    ap_status_t stat;
    int sockdes;

    ap_my_pid = getpid();
    csd = NULL;
    my_child_num = child_num_arg;
    requests_this_child = 0;
    last_lr = NULL;

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

    ap_create_pool(&ptrans, 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, ap_server_conf);

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

    ap_signal(SIGHUP, just_die);
    ap_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;
    ap_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, errno, ap_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 {
                    ap_get_os_sock(&sockdes, lr->sd);
            if (FD_ISSET(sockdes, &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->sd;
        }
        else {
        /* only one socket, just pretend we did the other stuff */
        sd = ap_listeners->sd;
        }

        /* 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);
        }
        stat = ap_accept(&csd, sd, ptrans);
        if (stat == APR_SUCCESS || stat != APR_EINTR)
            break;
        }

        if (stat == APR_SUCCESS)
        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, errno, ap_server_conf,
            "accept: giving up.");
            clean_child_exit(APEXIT_CHILDFATAL);
#endif /*ENETDOWN*/

#ifdef TPF
        case EINACT:
            ap_log_error(APLOG_MARK, APLOG_EMERG, errno, ap_server_conf,
            "offload device inactive");
            clean_child_exit(APEXIT_CHILDFATAL);
            break;
        default:
            ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_ERR, 0, ap_server_conf,
            "select/accept error (%u)", errno);
            clean_child_exit(APEXIT_CHILDFATAL);
#else
        default:
            ap_log_error(APLOG_MARK, APLOG_ERR, errno, ap_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.
     */
    ap_signal(SIGUSR1, SIG_IGN);
    /*
     * We now have a connection, so set it up with the appropriate
     * socket options, file descriptors, and read/write buffers.
     */

        ap_get_os_sock(&sockdes, csd);

    sock_disable_nagle(sockdes);

    iol = unix_attach_socket(csd);
    if (iol == NULL) {
        if (errno == EBADF) {
        ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_WARNING, 0, NULL,
            "filedescriptor (%u) larger than FD_SETSIZE (%u) "
            "found, you probably need to rebuild Apache with a "
            "larger FD_SETSIZE", sockdes, FD_SETSIZE);
        }
        else {
        ap_log_error(APLOG_MARK, APLOG_WARNING, errno, NULL,
            "error attaching to socket");
        }
        ap_close_socket(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_apr_connection(ptrans, ap_server_conf, conn_io, csd,
                     my_child_num);

    ap_process_connection(current_conn);
        ap_lingering_close(current_conn);
    }
}


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

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

    if (one_process) {
    ap_signal(SIGHUP, just_die);
    ap_signal(SIGINT, just_die);
#ifdef SIGQUIT
    ap_signal(SIGQUIT, SIG_DFL);
#endif
    ap_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, errno, s, "fork: Unable to fork new process");

    /* fork didn't succeed. Fix the scoreboard or else
     * it will say SERVER_STARTING forever and ever
     */
    (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, ap_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.
     */
    ap_signal(SIGHUP, just_die);
    ap_signal(SIGUSR1, just_die);
    ap_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(ap_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 >= ap_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;
    }
    }
    ap_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, 0, ap_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, 0, ap_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(ap_server_conf, free_slots[i], now) == -1) {
            if(free_length == 1) {
                shutdown_pending = 1;
                ap_log_error(APLOG_MARK, APLOG_EMERG, ap_server_conf,
                "No active child processes: shutting down");
            }
        }
#else
        make_child(ap_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(ap_proc_t *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, 0, ap_server_conf,
            "Child %ld returned a Fatal error... \n"
            "Apache is exiting!",
            (long)pid->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,
                 0, ap_server_conf,
                 "child pid %ld exit signal %s (%d), "
                 "possible coredump in %s",
                 (long)pid->pid, (WTERMSIG(status) >= NumSIG) ? "" :
                 SYS_SIGLIST[WTERMSIG(status)], WTERMSIG(status),
                 ap_coredump_dir);
        }
        else {
#endif
        ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_NOTICE,
                 0, ap_server_conf,
                 "child pid %ld exit signal %s (%d)", (long)pid->pid,
                 SYS_SIGLIST[WTERMSIG(status)], WTERMSIG(status));
#ifdef WCOREDUMP
        }
#endif
#else
        ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_NOTICE,
             ap_server_conf,
             "child pid %ld exit signal %d",
             (long)pid->pid, WTERMSIG(status));
#endif
    }
    }
}


static int setup_listeners(server_rec *s)
{
    ap_listen_rec *lr;
    int sockdes;

    if (ap_listen_open(s->process, s->port)) {
    ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_ALERT, 0, s,
            "no listening sockets available, shutting down");
    return -1;
    }

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

/* Useful to erase the status of children that might be from previous
 * generations */
static void ap_prefork_force_reset_connection_status(long conn_id)
{
    int i;

    for (i = 0; i < STATUSES_PER_CONNECTION; i++) {
        ap_new_scoreboard_image->table[conn_id][i].key[0] = '\0';
    }                                                                           }

void ap_reset_connection_status(long conn_id)
{
    if (maintain_connection_status) {
        ap_prefork_force_reset_connection_status(conn_id);
    }
}

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

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

    pconf = _pconf;

    ap_server_conf = s;

    ap_log_pid(pconf, ap_pid_fname);

    if (setup_listeners(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, 0, ap_server_conf,
        "%s configured -- resuming normal operations",
        ap_get_server_version());
    ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_INFO, 0, ap_server_conf,
        "Server built: %s", ap_get_server_built());
    restart_pending = shutdown_pending = 0;

    while (!restart_pending && !shutdown_pending) {
    int child_slot;
    ap_wait_t status;
        /* this is a memory leak, but I'll fix it later. */
    ap_proc_t pid;

        ap_wait_or_timeout(&status, &pid, pconf);

    /* 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.pid != -1) {
        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) {
                ap_prefork_force_reset_connection_status(child_slot);
        (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(ap_server_conf, child_slot, time(0));
            --remaining_children_to_start;
        }
#ifdef APR_HAS_OTHER_CHILD
        }
        else if (ap_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,
                            0, ap_server_conf,
                "long lost child came home! (pid %ld)", (long)pid.pid);
        }
        /* Don't perform idle maintenance when a child dies,
        * only do it when there's a timeout.  Remember only a
        * finite number of children can die, and it's pretty
        * pathological for a lot to die suddenly.
        */
        continue;
    }
    else if (remaining_children_to_start) {
        /* we hit a 1 second timeout in which none of the previous
        * generation of children needed to be reaped... so assume
        * they're all done, and pick up the slack if any is left.
        */
        startup_children(remaining_children_to_start);
        remaining_children_to_start = 0;
        /* In any event we really shouldn't do the code below because
        * few of the servers we just started are in the IDLE state
        * yet, so we'd mistakenly create an extra server.
        */
        continue;
    }

    perform_idle_server_maintenance();
#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 (unixd_killpg(getpgrp(), SIGTERM) < 0) {
        ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "killpg SIGTERM");
    }
    ap_reclaim_child_processes(1);      /* Start with SIGTERM */

    /* cleanup pid file on normal shutdown */
    {
        const char *pidfile = NULL;
        pidfile = ap_server_root_relative (pconf, ap_pid_fname);
        if ( pidfile != NULL && unlink(pidfile) == 0)
        ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_INFO,
                0, ap_server_conf,
                "removed PID file %s (pid=%ld)",
                pidfile, (long)getpid());
    }

    ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_NOTICE, 0, ap_server_conf,
            "caught SIGTERM, shutting down");
    return 1;
    }

    /* we've been told to restart */
    ap_signal(SIGHUP, SIG_IGN);
    ap_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, 0, ap_server_conf,
            "SIGUSR1 received.  Doing graceful restart");

    /* kill off the idle ones */
    if (unixd_killpg(getpgrp(), SIGUSR1) < 0) {
        ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_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 (unixd_killpg(getpgrp(), SIGHUP) < 0) {
        ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "killpg SIGHUP");
    }
    ap_reclaim_child_processes(0);      /* Not when just starting up */
    ap_log_error(APLOG_MARK, APLOG_NOERRNO|APLOG_NOTICE, 0, ap_server_conf,
            "SIGHUP received.  Attempting to restart");
    }

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

    return 0;
}

static void prefork_pre_config(ap_pool_t *p, ap_pool_t *plog, ap_pool_t *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) {
        ap_detach();
    }

    ap_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)
{
    INIT_SIGLIST();
#ifdef AUX3
    (void) set42sig();
#endif
    /* TODO: set one_process properly */ one_process = 0;

    ap_hook_pre_config(prefork_pre_config, NULL, NULL, AP_HOOK_MIDDLE);
}

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

    ap_daemons_to_start = atoi(arg);
    return NULL;
}

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

    ap_daemons_min_free = atoi(arg);
    if (ap_daemons_min_free <= 0) {
       ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
                    "WARNING: detected MinSpareServers set to non-positive.");
       ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
                    "Resetting to 1 to avoid almost certain Apache failure.");
       ap_log_error(APLOG_MARK, APLOG_STARTUP | APLOG_NOERRNO, 0, NULL,
                    "Please read the documentation.");
       ap_daemons_min_free = 1;
    }

    return NULL;
}

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

    ap_daemons_max_free = atoi(arg);
    return NULL;
}

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

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

static const char *set_max_requests(cmd_parms *cmd, void *dummy, const 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, const char *arg)
{
    ap_finfo_t 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);
    if ((ap_stat(&finfo, fname, cmd->pool) != APR_SUCCESS) ||
        (finfo.filetype != APR_DIR)) {
    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;
}

/* Stub functions until this MPM supports the connection status API */
/* Don't mess with the string you get back from this function */
const char *ap_get_connection_status(long conn_id, const char *key)
{
    int i = 0;
    status_table_entry *ss;

    if (!maintain_connection_status) return "";
    while (i < STATUSES_PER_CONNECTION) {
        ss = &(ap_new_scoreboard_image->table[conn_id][i]);
        if (ss->key[0] == '\0') {
            break;
        }
        if (0 == strcmp(ss->key, key)) {
            return ss->value;
        }
    }

    return NULL;
}

ap_array_header_t *ap_get_connections(ap_pool_t *p)
{
    int i;
    ap_array_header_t *connection_list;
    long *array_slot;

    connection_list = ap_make_array(p, 0, sizeof(long));
    /* We assume that there is a connection iff it has an entry in the status
     * table. Connections without any status sound problematic to me, so this
     * is probably for the best. - manoj */
    for (i = 0; i < ap_max_daemons_limit; i++) {
         if (ap_new_scoreboard_image->table[i][0].key[0] != '\0') {
            array_slot = ap_push_array(connection_list);
            *array_slot = i;
        }
    }
    return connection_list;
}

ap_array_header_t *ap_get_connection_keys(ap_pool_t *p, long conn_id)
{
    int i = 0;
    status_table_entry *ss;
    ap_array_header_t *key_list;
    char **array_slot;

    key_list = ap_make_array(p, 0, KEY_LENGTH * sizeof(char));
    while (i < STATUSES_PER_CONNECTION) {
        ss = &(ap_new_scoreboard_image->table[conn_id][i]);
        if (ss->key[0] == '\0') {
            break;
        }
        array_slot = ap_push_array(key_list);
        *array_slot = ap_pstrdup(p, ss->key);
        i++;
    }
    return key_list;
}

/* Note: no effort is made here to prevent multiple threads from messing with
 * a single connection at the same time. ap_update_connection_status should
 * only be called by the thread that owns the connection */

void ap_update_connection_status(long conn_id, const char *key,
                                 const char *value)
{
    int i = 0;
    status_table_entry *ss;

    if (!maintain_connection_status) return;
    while (i < STATUSES_PER_CONNECTION) {
        ss = &(ap_new_scoreboard_image->table[conn_id][i]);
        if (ss->key[0] == '\0') {
            break;
        }
        if (0 == strcmp(ss->key, key)) {
            ap_cpystrn(ss->value, value, VALUE_LENGTH);
            return;
        }
        i++;
    }
    /* Not found. Add an entry for this value */
    if (i >= STATUSES_PER_CONNECTION) {
        /* No room. Oh well, not much anyone can do about it. */
        return;
    }
    ap_cpystrn(ss->key, key, KEY_LENGTH);
    ap_cpystrn(ss->value, value, VALUE_LENGTH);
    return;
}

ap_array_header_t *ap_get_status_table(ap_pool_t *p)
{
    int i, j;
    ap_array_header_t *server_status;
    ap_status_table_row_t *array_slot;
    status_table_entry *ss;

    server_status = ap_make_array(p, 0, sizeof(ap_status_table_row_t));

    /* Go ahead and return what's in the connection status table even if we
     * aren't maintaining it. We can at least look at what children from
     * previous generations are up to. */

    for (i = 0; i < ap_max_daemons_limit; i++) {
        if (ap_new_scoreboard_image->table[i][0].key[0] == '\0')
            continue;
        array_slot = ap_push_array(server_status);
        array_slot->data = ap_make_table(p, 0);
        array_slot->conn_id = i;

        for (j = 0; j < STATUSES_PER_CONNECTION; j++) {
            ss = &(ap_new_scoreboard_image->table[i][j]);
            if (ss->key[0] != '\0') {
                ap_table_add(array_slot->data, ss->key, ss->value);
            }
            else {
                break;
            }
        }
    }
    return server_status;
}

static const command_rec prefork_cmds[] = {
UNIX_DAEMON_COMMANDS
LISTEN_COMMANDS
AP_INIT_TAKE1("PidFile", set_pidfile, NULL, RSRC_CONF,
              "A file for logging the server process ID"),
AP_INIT_TAKE1("ScoreBoardFile", set_scoreboard, NULL, RSRC_CONF,
              "A file for Apache to maintain runtime process management information"),
AP_INIT_TAKE1("LockFile", set_lockfile, NULL, RSRC_CONF,
              "The lockfile used when Apache needs to lock the accept() call"),
AP_INIT_TAKE1("StartServers", set_daemons_to_start, NULL, RSRC_CONF,
              "Number of child processes launched at server startup"),
AP_INIT_TAKE1("MinSpareServers", set_min_free_servers, NULL, RSRC_CONF,
              "Minimum number of idle children, to handle request spikes"),
AP_INIT_TAKE1("MaxSpareServers", set_max_free_servers, NULL, RSRC_CONF,
              "Maximum number of idle children"),
AP_INIT_TAKE1("MaxClients", set_server_limit, NULL, RSRC_CONF,
              "Maximum number of children alive at the same time"),
AP_INIT_TAKE1("MaxRequestsPerChild", set_max_requests, NULL, RSRC_CONF,
              "Maximum number of requests a particular child serves before dying."),
AP_INIT_TAKE1("CoreDumpDirectory", set_coredumpdir, NULL, RSRC_CONF,
              "The location of the directory Apache changes to before dumping core"),
{ NULL }
};

module MODULE_VAR_EXPORT mpm_prefork_module = {
    MPM20_MODULE_STUFF,
    NULL,                       /* hook to run before apache parses args */
    NULL,           /* create per-directory config structure */
    NULL,           /* merge per-directory config structures */
    NULL,           /* create per-server config structure */
    NULL,           /* merge per-server config structures */
    prefork_cmds,       /* command ap_table_t */
    NULL,           /* handlers */
    prefork_hooks,      /* register hooks */
};