beos.c

Apache官方在今天放出产品系列2.2的最新版本2.2.11的源码包 最流行的HTTP服务器软件之一

/* Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/* The BeOS MPM!
 *
 * This is a single process, with multiple worker threads.
 *
 * Under testing I found that given the inability of BeOS to handle threads
 * and forks it didn't make sense to try and have a set of "children" threads
 * that spawned the "worker" threads, so just missed out the middle mand and
 * somehow arrived here.
 *
 * For 2.1 this has been rewritten to have simpler logic, though there is still
 * some simplification that can be done. It's still a work in progress!
 *
 * TODO Items
 *
 * - on exit most worker threads segfault trying to access a kernel page.
 */

#define CORE_PRIVATE

#include <kernel/OS.h>
#include <unistd.h>
#include <sys/socket.h>
#include <signal.h>

#include "apr_strings.h"
#include "apr_portable.h"
#include "httpd.h"
#include "http_main.h"
#include "http_log.h"
#include "http_config.h"        /* for read_config */
#include "http_core.h"          /* for get_remote_host */
#include "http_connection.h"
#include "ap_mpm.h"
#include "beosd.h"
#include "ap_listen.h"
#include "scoreboard.h"
#include "mpm_common.h"
#include "mpm.h"
#include "mpm_default.h"
#include "apr_thread_mutex.h"
#include "apr_poll.h"

extern int _kset_fd_limit_(int num);

/* Limit on the total --- clients will be locked out if more servers than
 * this are needed.  It is intended solely to keep the server from crashing
 * when things get out of hand.
 *
 * We keep a hard maximum number of servers, for two reasons:
 * 1) in case something goes seriously wrong, we want to stop the server starting
 *    threads ad infinitum and crashing the server (remember that BeOS has a 192
 *    thread per team limit).
 * 2) it keeps the size of the scoreboard file small
 *    enough that we can read the whole thing without worrying too much about
 *    the overhead.
 */

/* we only ever have 1 main process running... */
#define HARD_SERVER_LIMIT 1

/* Limit on the threads per process.  Clients will be locked out if more than
 * this  * HARD_SERVER_LIMIT are needed.
 *
 * We keep this for one reason it keeps the size of the scoreboard file small
 * enough that we can read the whole thing without worrying too much about
 * the overhead.
 */
#ifdef NO_THREADS
#define HARD_THREAD_LIMIT 1
#endif
#ifndef HARD_THREAD_LIMIT
#define HARD_THREAD_LIMIT 50
#endif

/*
 * Actual definitions of config globals
 */

static int ap_threads_to_start=0;
static int ap_max_requests_per_thread = 0;
static int min_spare_threads=0;
static int max_spare_threads=0;
static int ap_thread_limit=0;
static int num_listening_sockets = 0;
static int mpm_state = AP_MPMQ_STARTING;
apr_thread_mutex_t *accept_mutex = NULL;

static apr_pool_t *pconf;    /* Pool for config stuff */

static int server_pid;


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

static apr_socket_t *udp_sock;
static apr_sockaddr_t *udp_sa;

server_rec *ap_server_conf;

/* one_process */
static int one_process = 0;

#ifdef DEBUG_SIGSTOP
int raise_sigstop_flags;
#endif

static void check_restart(void *data);

/* When a worker thread gets to the end of it's life it dies with an
 * exit value of the code supplied to this function. The thread has
 * already had check_restart() registered to be called when dying, so
 * we don't concern ourselves with restarting at all here. We do however
 * mark the scoreboard slot as belonging to a dead server and zero out
 * it's thread_id.
 *
 * TODO - use the status we set to determine if we need to restart the
 *        thread.
 */
static void clean_child_exit(int code, int slot)
{
    (void) ap_update_child_status_from_indexes(0, slot, SERVER_DEAD,
                                               (request_rec*)NULL);
    ap_scoreboard_image->servers[0][slot].tid = 0;
    exit_thread(code);
}


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

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

/*
 * ap_start_shutdown() and ap_start_restart(), below, are a first stab at
 * functions to initiate shutdown or restart without relying on signals.
 * Previously this was initiated in sig_term() and restart() signal handlers,
 * but we want to be able to start a shutdown/restart from other sources --
 * e.g. on Win32, from the service manager. Now the service manager can
 * call ap_start_shutdown() or ap_start_restart() as appropiate.  Note that
 * these functions can also be called by the child processes, since global
 * variables are no longer used to pass on the required action to the parent.
 *
 * These should only be called from the parent process itself, since the
 * parent process will use the shutdown_pending and restart_pending variables
 * to determine whether to shutdown or restart. The child process should
 * call signal_parent() directly to tell the parent to die -- this will
 * cause neither of those variable to be set, which the parent will
 * assume means something serious is wrong (which it will be, for the
 * child to force an exit) and so do an exit anyway.
 */

static void ap_start_shutdown(void)
{
    /* If the user tries to shut us down twice in quick succession then we
     * may well get triggered while we are working through previous attempt
     * to shutdown. We won't worry about even reporting it as it seems a little
     * pointless.
     */
    if (shutdown_pending == 1)
        return;

    shutdown_pending = 1;
}

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

/* sig_coredump attempts to handle all the potential signals we
 * may get that should result in a core dump. This is called from
 * the signal handler routine, so when we enter we are essentially blocked
 * on the signal. Once we exit we will allow the signal to be processed by
 * system, which may or may not produce a .core file. All this function does
 * is try and respect the users wishes about where that file should be
 * located (chdir) and then signal the parent with the signal.
 *
 * If we called abort() the parent would only see SIGABRT which doesn't provide
 * as much information.
 */
static void sig_coredump(int sig)
{
    chdir(ap_coredump_dir);
    signal(sig, SIG_DFL);
    kill(server_pid, sig);
}

static void sig_term(int sig)
{
    ap_start_shutdown();
}

static void restart(int sig)
{
    ap_start_restart(sig == AP_SIG_GRACEFUL);
}

/* Handle queries about our inner workings... */
AP_DECLARE(apr_status_t) ap_mpm_query(int query_code, int *result)
{
    switch(query_code){
        case AP_MPMQ_MAX_DAEMON_USED:
            *result = ap_max_child_assigned;
            return APR_SUCCESS;
        case AP_MPMQ_IS_THREADED:
            *result = AP_MPMQ_DYNAMIC;
            return APR_SUCCESS;
        case AP_MPMQ_IS_FORKED:
            *result = AP_MPMQ_NOT_SUPPORTED;
            return APR_SUCCESS;
        case AP_MPMQ_HARD_LIMIT_DAEMONS:
            *result = HARD_SERVER_LIMIT;
            return APR_SUCCESS;
        case AP_MPMQ_HARD_LIMIT_THREADS:
            *result = HARD_THREAD_LIMIT;
            return APR_SUCCESS;
        case AP_MPMQ_MAX_THREADS:
            *result = HARD_THREAD_LIMIT;
            return APR_SUCCESS;
        case AP_MPMQ_MIN_SPARE_DAEMONS:
            *result = 0;
            return APR_SUCCESS;
        case AP_MPMQ_MIN_SPARE_THREADS:
            *result = max_spare_threads;
            return APR_SUCCESS;
        case AP_MPMQ_MAX_SPARE_DAEMONS:
            *result = 0;
            return APR_SUCCESS;
        case AP_MPMQ_MAX_SPARE_THREADS:
            *result = min_spare_threads;
            return APR_SUCCESS;
        case AP_MPMQ_MAX_REQUESTS_DAEMON:
            *result = ap_max_requests_per_thread;
            return APR_SUCCESS;
        case AP_MPMQ_MAX_DAEMONS:
            *result = HARD_SERVER_LIMIT;
            return APR_SUCCESS;
        case AP_MPMQ_MPM_STATE:
            *result = mpm_state;
            return APR_SUCCESS;
    }
    return APR_ENOTIMPL;
}

/* This accepts a connection and allows us to handle the error codes better than
 * the previous code, while also making it more obvious.
 */
static apr_status_t beos_accept(void **accepted, ap_listen_rec *lr, apr_pool_t *ptrans)
{
    apr_socket_t *csd;
    apr_status_t status;
    int sockdes;

    *accepted = NULL;
    status = apr_socket_accept(&csd, lr->sd, ptrans);
    if (status == APR_SUCCESS) {
        *accepted = csd;
        apr_os_sock_get(&sockdes, csd);
        return status;
    }

    if (APR_STATUS_IS_EINTR(status)) {
        return status;
    }
        /* This switch statement provides us with better error details. */
    switch (status) {
#ifdef ECONNABORTED
        case ECONNABORTED:
#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, status, ap_server_conf,
                         "apr_socket_accept: giving up.");
            return APR_EGENERAL;
#endif /*ENETDOWN*/

        default:
            ap_log_error(APLOG_MARK, APLOG_ERR, status, ap_server_conf,
                         "apr_socket_accept: (client socket)");
            return APR_EGENERAL;
    }
    return status;
}

static void tell_workers_to_exit(void)
{
    apr_size_t len;
    int i = 0;
    for (i = 0 ; i < ap_max_child_assigned; i++){
        len = 4;
        if (apr_socket_sendto(udp_sock, udp_sa, 0, "die!", &len) != APR_SUCCESS)
            break;
    }
}

static void set_signals(void)
{
    struct sigaction sa;

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

    /* The first batch get handled by sig_coredump */
    if (!one_process) {
        sa.sa_handler = sig_coredump;

        if (sigaction(SIGSEGV, &sa, NULL) < 0)
            ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "sigaction(SIGSEGV)");
        if (sigaction(SIGBUS, &sa, NULL) < 0)
            ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "sigaction(SIGBUS)");
        if (sigaction(SIGABRT, &sa, NULL) < 0)
            ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "sigaction(SIGABRT)");
        if (sigaction(SIGILL, &sa, NULL) < 0)
            ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "sigaction(SIGILL)");
        sa.sa_flags = 0;
    }

    /* These next two are handled by sig_term */
    sa.sa_handler = sig_term;
    if (sigaction(SIGTERM, &sa, NULL) < 0)
            ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "sigaction(SIGTERM)");
    if (sigaction(SIGINT, &sa, NULL) < 0)
        ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "sigaction(SIGINT)");

    /* We ignore 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)");

    /* we want to ignore HUPs and AP_SIG_GRACEFUL while we're busy
     * processing one */
    sigaddset(&sa.sa_mask, SIGHUP);
    sigaddset(&sa.sa_mask, AP_SIG_GRACEFUL);
    sa.sa_handler = restart;
    if (sigaction(SIGHUP, &sa, NULL) < 0)
        ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "sigaction(SIGHUP)");
    if (sigaction(AP_SIG_GRACEFUL, &sa, NULL) < 0)
            ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf, "sigaction(" AP_SIG_GRACEFUL_STRING ")");
}

/*****************************************************************
 * Here follows a long bunch of generic server bookkeeping stuff...
 */

int ap_graceful_stop_signalled(void)