worker.c

apache的软件linux版本

 * 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)
{
    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;
}

/* 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();
}

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 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 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 void process_socket(apr_pool_t *p, apr_socket_t *sock, int my_child_num,
                           int my_thread_num, apr_bucket_alloc_t *bucket_alloc)
{
    conn_rec *current_conn;
    long conn_id = ID_FROM_CHILD_THREAD(my_child_num, my_thread_num);
    int csd;
    ap_sb_handle_t *sbh;

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

    current_conn = ap_run_create_connection(p, ap_server_conf, sock,
                                            conn_id, sbh, bucket_alloc);
    if (current_conn) {
        ap_process_connection(current_conn, sock);
        ap_lingering_close(current_conn);
    }
}

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

static void unblock_signal(int sig)
{
    sigset_t sig_mask;

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

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

static void *listener_thread(apr_thread_t *thd, void * dummy)
{
    proc_info * ti = dummy;
    int process_slot = ti->pid;
    apr_pool_t *tpool = apr_thread_pool_get(thd);
    void *csd = NULL;
    apr_pool_t *ptrans = NULL;            /* Pool for per-transaction stuff */
    int n;
    apr_pollfd_t *pollset;
    apr_status_t rv;
    ap_listen_rec *lr, *last_lr = ap_listeners;
    int have_idle_worker = 0;

    free(ti);

    apr_poll_setup(&pollset, num_listensocks, tpool);
    for(lr = ap_listeners ; lr != NULL ; lr = lr->next)
        apr_poll_socket_add(pollset, lr->sd, APR_POLLIN);

    /* Unblock the signal used to wake this thread up, and set a handler for
     * it.
     */
    unblock_signal(LISTENER_SIGNAL);
    apr_signal(LISTENER_SIGNAL, dummy_signal_handler);

    /* TODO: Switch to a system where threads reuse the results from earlier
       poll calls - manoj */
    while (1) {
        /* TODO: requests_this_child should be synchronized - aaron */
        if (requests_this_child <= 0) {
            check_infinite_requests();
        }
        if (listener_may_exit) break;

        if (!have_idle_worker) {
            /* the following pops a recycled ptrans pool off a stack
             * if there is one, in addition to reserving a worker thread
             */
            rv = ap_queue_info_wait_for_idler(worker_queue_info,
                                              &ptrans);
            if (APR_STATUS_IS_EOF(rv)) {
                break; /* we've been signaled to die now */
            }
            else if (rv != APR_SUCCESS) {
                ap_log_error(APLOG_MARK, APLOG_EMERG, rv, ap_server_conf,
                             "apr_queue_info_wait failed. Attempting to "
                             " shutdown process gracefully.");
                signal_threads(ST_GRACEFUL);
                break;
            }
            have_idle_worker = 1;
        }
            
        /* We've already decremented the idle worker count inside
         * ap_queue_info_wait_for_idler. */

        if ((rv = SAFE_ACCEPT(apr_proc_mutex_lock(accept_mutex)))
            != APR_SUCCESS) {
            int level = APLOG_EMERG;

            if (listener_may_exit) {
                break;
            }
            if (ap_scoreboard_image->parent[process_slot].generation != 
                ap_scoreboard_image->global->running_generation) {
                level = APLOG_DEBUG; /* common to get these at restart time */
            }
            ap_log_error(APLOG_MARK, level, rv, ap_server_conf,
                         "apr_proc_mutex_lock failed. Attempting to shutdown "
                         "process gracefully.");
            signal_threads(ST_GRACEFUL);
            break;                    /* skip the lock release */
        }

        if (!ap_listeners->next) {
            /* Only one listener, so skip the poll */
            lr = ap_listeners;
        }
        else {
            while (!listener_may_exit) {
                apr_status_t ret;
                apr_int16_t event;

                ret = apr_poll(pollset, num_listensocks, &n, -1);
                if (ret != APR_SUCCESS) {
                    if (APR_STATUS_IS_EINTR(ret)) {
                        continue;
                    }

                    /* apr_pollset_poll() will only return errors in catastrophic
                     * circumstances. Let's try exiting gracefully, for now. */
                    ap_log_error(APLOG_MARK, APLOG_ERR, ret, (const server_rec *)
                                 ap_server_conf, "apr_poll: (listen)");
                    signal_threads(ST_GRACEFUL);
                }

                if (listener_may_exit) break;

                /* find a listener */
                lr = last_lr;
                do {
                    lr = lr->next;
                    if (lr == NULL) {
                        lr = ap_listeners;
                    }
                    /* XXX: Should we check for POLLERR? */
                    apr_poll_revents_get(&event, lr->sd, pollset);
                    if (event & APR_POLLIN) {
                        last_lr = lr;
                        goto got_fd;
                    }
                } while (lr != last_lr);
            }
        }
    got_fd:
        if (!listener_may_exit) {
            if (ptrans == NULL) {
                /* we can't use a recycled transaction pool this time.
                 * create a new transaction pool */
                apr_allocator_t *allocator;

                apr_allocator_create(&allocator);
                apr_allocator_max_free_set(allocator, ap_max_mem_free);
                apr_pool_create_ex(&ptrans, NULL, NULL, allocator);
                apr_allocator_owner_set(allocator, ptrans);
            }
            apr_pool_tag(ptrans, "transaction");
            rv = lr->accept_func(&csd, lr, ptrans);
            /* later we trash rv and rely on csd to indicate success/failure */
            AP_DEBUG_ASSERT(rv == APR_SUCCESS || !csd);

            if (rv == APR_EGENERAL) {
                /* E[NM]FILE, ENOMEM, etc */
                resource_shortage = 1;
                signal_threads(ST_GRACEFUL);
            }
            if ((rv = SAFE_ACCEPT(apr_proc_mutex_unlock(accept_mutex)))
                != APR_SUCCESS) {
                int level = APLOG_EMERG;

                if (listener_may_exit) {
                    break;
                }
                if (ap_scoreboard_image->parent[process_slot].generation != 
                    ap_scoreboard_image->global->running_generation) {
                    level = APLOG_DEBUG; /* common to get these at restart time */
                }
                ap_log_error(APLOG_MARK, level, rv, ap_server_conf,
                             "apr_proc_mutex_unlock failed. Attempting to "
                             "shutdown process gracefully.");
                signal_threads(ST_GRACEFUL);
            }
            if (csd != NULL) {
                rv = ap_queue_push(worker_queue, csd, ptrans);
                if (rv) {
                    /* trash the connection; we couldn't queue the connected
                     * socket to a worker 
                     */
                    apr_socket_close(csd);
                    ap_log_error(APLOG_MARK, APLOG_CRIT, rv, ap_server_conf,
                                 "ap_queue_push failed");
                }
                else {
                    have_idle_worker = 0;
                }
            }