event.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

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

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

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

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

static void ap_start_shutdown(int graceful)
{
    mpm_state = AP_MPMQ_STOPPING;
    if (shutdown_pending == 1) {
        /* Um, is this _probably_ not an error, if the user has
         * tried to do a shutdown twice quickly, so we won't
         * worry about reporting it.
         */
        return;
    }
    shutdown_pending = 1;
    is_graceful = graceful;
}

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

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

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

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

    if (!one_process) {
        ap_fatal_signal_setup(ap_server_conf, pconf);
    }

#ifndef NO_USE_SIGACTION
    sigemptyset(&sa.sa_mask);
    sa.sa_flags = 0;

    sa.sa_handler = sig_term;
    if (sigaction(SIGTERM, &sa, NULL) < 0)
        ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf,
                     "sigaction(SIGTERM)");
#ifdef AP_SIG_GRACEFUL_STOP
    if (sigaction(AP_SIG_GRACEFUL_STOP, &sa, NULL) < 0)
        ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf,
                     "sigaction(" AP_SIG_GRACEFUL_STOP_STRING ")");
#endif
#ifdef SIGINT
    if (sigaction(SIGINT, &sa, NULL) < 0)
        ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf,
                     "sigaction(SIGINT)");
#endif
#ifdef SIGXCPU
    sa.sa_handler = SIG_DFL;
    if (sigaction(SIGXCPU, &sa, NULL) < 0)
        ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf,
                     "sigaction(SIGXCPU)");
#endif
#ifdef SIGXFSZ
    sa.sa_handler = SIG_DFL;
    if (sigaction(SIGXFSZ, &sa, NULL) < 0)
        ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf,
                     "sigaction(SIGXFSZ)");
#endif
#ifdef SIGPIPE
    sa.sa_handler = SIG_IGN;
    if (sigaction(SIGPIPE, &sa, NULL) < 0)
        ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf,
                     "sigaction(SIGPIPE)");
#endif

    /* we want to ignore HUPs and AP_SIG_GRACEFUL while we're busy
     * processing one */
    sigaddset(&sa.sa_mask, SIGHUP);
    sigaddset(&sa.sa_mask, AP_SIG_GRACEFUL);
    sa.sa_handler = restart;
    if (sigaction(SIGHUP, &sa, NULL) < 0)
        ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf,
                     "sigaction(SIGHUP)");
    if (sigaction(AP_SIG_GRACEFUL, &sa, NULL) < 0)
        ap_log_error(APLOG_MARK, APLOG_WARNING, errno, ap_server_conf,
                     "sigaction(" AP_SIG_GRACEFUL_STRING ")");
#else
    if (!one_process) {
#ifdef SIGXCPU
        apr_signal(SIGXCPU, SIG_DFL);
#endif /* SIGXCPU */
#ifdef SIGXFSZ
        apr_signal(SIGXFSZ, SIG_DFL);
#endif /* SIGXFSZ */
    }

    apr_signal(SIGTERM, sig_term);
#ifdef SIGHUP
    apr_signal(SIGHUP, restart);
#endif /* SIGHUP */
#ifdef AP_SIG_GRACEFUL
    apr_signal(AP_SIG_GRACEFUL, restart);
#endif /* AP_SIG_GRACEFUL */
#ifdef AP_SIG_GRACEFUL_STOP
     apr_signal(AP_SIG_GRACEFUL_STOP, sig_term);
#endif /* AP_SIG_GRACEFUL_STOP */
#ifdef SIGPIPE
    apr_signal(SIGPIPE, SIG_IGN);
#endif /* SIGPIPE */

#endif
}

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

int ap_graceful_stop_signalled(void)
    /* XXX this is really a bad confusing obsolete name
     * maybe it should be ap_mpm_process_exiting?
     */
{
    /* note: for a graceful termination, listener_may_exit will be set before
     *       workers_may_exit, so check listener_may_exit
     */
    return listener_may_exit;
}

/*****************************************************************
 * Child process main loop.
 */

static int process_socket(apr_pool_t * p, apr_socket_t * sock,
                          conn_state_t * cs, int my_child_num,
                          int my_thread_num)
{
    conn_rec *c;
    listener_poll_type *pt;
    long conn_id = ID_FROM_CHILD_THREAD(my_child_num, my_thread_num);
    int csd;
    int rc;
    apr_time_t time_now = 0;
    ap_sb_handle_t *sbh;

    ap_create_sb_handle(&sbh, p, my_child_num, my_thread_num);
    apr_os_sock_get(&csd, sock);

    time_now = apr_time_now();

    if (cs == NULL) {           /* This is a new connection */

        cs = apr_pcalloc(p, sizeof(conn_state_t));

        pt = apr_pcalloc(p, sizeof(*pt));

        cs->bucket_alloc = apr_bucket_alloc_create(p);
        c = ap_run_create_connection(p, ap_server_conf, sock,
                                     conn_id, sbh, cs->bucket_alloc);
        cs->c = c;
        c->cs = cs;
        cs->p = p;
        cs->pfd.desc_type = APR_POLL_SOCKET;
        cs->pfd.reqevents = APR_POLLIN;
        cs->pfd.desc.s = sock;
        pt->type = PT_CSD;
        pt->status = 1;
        pt->baton = cs;
        cs->pfd.client_data = pt;

        ap_update_vhost_given_ip(c);

        rc = ap_run_pre_connection(c, sock);
        if (rc != OK && rc != DONE) {
            ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, ap_server_conf,
                         "process_socket: connection aborted");
            c->aborted = 1;
        }

        /**
         * XXX If the platform does not have a usable way of bundling
         * accept() with a socket readability check, like Win32,
         * and there are measurable delays before the
         * socket is readable due to the first data packet arriving,
         * it might be better to create the cs on the listener thread
         * with the state set to CONN_STATE_CHECK_REQUEST_LINE_READABLE
         *
         * FreeBSD users will want to enable the HTTP accept filter
         * module in their kernel for the highest performance
         * When the accept filter is active, sockets are kept in the
         * kernel until a HTTP request is received.
         */
        cs->state = CONN_STATE_READ_REQUEST_LINE;

    }
    else {
        c = cs->c;
        c->sbh = sbh;
    }

    if (c->clogging_input_filters && !c->aborted) {
        /* Since we have an input filter which 'cloggs' the input stream,
         * like mod_ssl, lets just do the normal read from input filters,
         * like the Worker MPM does.
         */
        ap_run_process_connection(c);
        cs->state = CONN_STATE_LINGER;
    }

    if (cs->state == CONN_STATE_READ_REQUEST_LINE) {
        if (!c->aborted) {
            ap_run_process_connection(c);

            /* state will be updated upon return
             * fall thru to either wait for readability/timeout or
             * do lingering close
             */
        }
        else {
            cs->state = CONN_STATE_LINGER;
        }
    }

    if (cs->state == CONN_STATE_LINGER) {
        ap_lingering_close(c);
        apr_pool_clear(p);
        ap_push_pool(worker_queue_info, p);
        return 0;
    }
    else if (cs->state == CONN_STATE_CHECK_REQUEST_LINE_READABLE) {
        apr_status_t rc;
        listener_poll_type *pt = (listener_poll_type *) cs->pfd.client_data;

        /* It greatly simplifies the logic to use a single timeout value here
         * because the new element can just be added to the end of the list and
         * it will stay sorted in expiration time sequence.  If brand new
         * sockets are sent to the event thread for a readability check, this
         * will be a slight behavior change - they use the non-keepalive
         * timeout today.  With a normal client, the socket will be readable in
         * a few milliseconds anyway.
         */
        cs->expiration_time = ap_server_conf->keep_alive_timeout + time_now;
        apr_thread_mutex_lock(timeout_mutex);
        APR_RING_INSERT_TAIL(&timeout_head, cs, conn_state_t, timeout_list);

        pt->status = 0;
        /* Add work to pollset. These are always read events */
        rc = apr_pollset_add(event_pollset, &cs->pfd);

        apr_thread_mutex_unlock(timeout_mutex);

        if (rc != APR_SUCCESS) {
            ap_log_error(APLOG_MARK, APLOG_ERR, rc, ap_server_conf,
                         "process_socket: apr_pollset_add failure");
            AP_DEBUG_ASSERT(rc == APR_SUCCESS);
        }
    }
    return 1;
}

/* requests_this_child has gone to zero or below.  See if the admin coded
   "MaxRequestsPerChild 0", and keep going in that case.  Doing it this way
   simplifies the hot path in worker_thread */
static void check_infinite_requests(void)
{
    if (ap_max_requests_per_child) {
        signal_threads(ST_GRACEFUL);
    }
    else {
        /* wow! if you're executing this code, you may have set a record.
         * either this child process has served over 2 billion requests, or
         * you're running a threaded 2.0 on a 16 bit machine.
         *
         * I'll buy pizza and beers at Apachecon for the first person to do
         * the former without cheating (dorking with INT_MAX, or running with
         * uncommitted performance patches, for example).
         *
         * for the latter case, you probably deserve a beer too.   Greg Ames
         */

        requests_this_child = INT_MAX;  /* keep going */
    }
}

static void unblock_signal(int sig)
{
    sigset_t sig_mask;

    sigemptyset(&sig_mask);
    sigaddset(&sig_mask, sig);
#if defined(SIGPROCMASK_SETS_THREAD_MASK)
    sigprocmask(SIG_UNBLOCK, &sig_mask, NULL);
#else
    pthread_sigmask(SIG_UNBLOCK, &sig_mask, NULL);
#endif
}

static void dummy_signal_handler(int sig)
{
    /* XXX If specifying SIG_IGN is guaranteed to unblock a syscall,
     *     then we don't need this goofy function.
     */
}

static apr_status_t push2worker(const apr_pollfd_t * pfd,
                                apr_pollset_t * pollset)
{
    listener_poll_type *pt = (listener_poll_type *) pfd->client_data;
    conn_state_t *cs = (conn_state_t *) pt->baton;
    apr_status_t rc;

    if (pt->status == 1) {
        return 0;
    }

    pt->status = 1;

    rc = apr_pollset_remove(pollset, pfd);

    /*
     * Some of the pollset backends, like KQueue or Epoll
     * automagically remove the FD if the socket is closed,
     * therefore, we can accept _SUCCESS or _NOTFOUND,
     * and we still want to keep going
     */
    if (rc != APR_SUCCESS && rc != APR_NOTFOUND) {
        cs->state = CONN_STATE_LINGER;
    }

    rc = ap_queue_push(worker_queue, cs->pfd.desc.s, cs, cs->p);
    if (rc != APR_SUCCESS) {
        /* trash the connection; we couldn't queue the connected
         * socket to a worker
         */
        apr_bucket_alloc_destroy(cs->bucket_alloc);
        apr_socket_close(cs->pfd.desc.s);
        ap_log_error(APLOG_MARK, APLOG_CRIT, rc,
                     ap_server_conf, "push2worker: ap_queue_push failed");
        apr_pool_clear(cs->p);