view src/event/ngx_event.c @ 34:aab2ea7c0458 NGINX_0_1_17

nginx 0.1.17 *) Change: the ngx_http_rewrite_module was rewritten from the scratch. Now it is possible to redirect, to return the error codes, to check the variables and referrers. The directives can be used inside locations. The redirect directive was canceled. *) Feature: the ngx_http_geo_module. *) Feature: the proxy_set_x_var and fastcgi_set_var directives. *) Bugfix: the location configuration with "=" modifier may be used in another location. *) Bugfix: the correct content type was set only for requests that use small caps letters in extension. *) Bugfix: if the proxy_pass or fastcgi_pass directives were set in the location, and access was denied, and the error was redirected to a static page, then the segmentation fault occurred. *) Bugfix: if in a proxied "Location" header was a relative URL, then a host name and a slash were added to them; bug appeared in 0.1.14. *) Bugfix: the system error message was not logged on Linux.
author Igor Sysoev <http://sysoev.ru>
date Thu, 03 Feb 2005 00:00:00 +0300
parents da8c190bdaba
children 41ccba1aba45
line wrap: on
line source


/*
 * Copyright (C) Igor Sysoev
 */


#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_event.h>


#define DEFAULT_CONNECTIONS  512


extern ngx_module_t ngx_kqueue_module;
extern ngx_module_t ngx_devpoll_module;
extern ngx_module_t ngx_epoll_module;
extern ngx_module_t ngx_rtsig_module;
extern ngx_module_t ngx_select_module;


static ngx_int_t ngx_event_module_init(ngx_cycle_t *cycle);
static ngx_int_t ngx_event_process_init(ngx_cycle_t *cycle);
static char *ngx_events_block(ngx_conf_t *cf, ngx_command_t *cmd, void *conf);

static char *ngx_event_connections(ngx_conf_t *cf, ngx_command_t *cmd,
                                   void *conf);
static char *ngx_event_use(ngx_conf_t *cf, ngx_command_t *cmd, void *conf);
static char *ngx_event_debug_connection(ngx_conf_t *cf, ngx_command_t *cmd,
                                        void *conf);

static void *ngx_event_create_conf(ngx_cycle_t *cycle);
static char *ngx_event_init_conf(ngx_cycle_t *cycle, void *conf);
static char *ngx_accept_mutex_check(ngx_conf_t *cf, void *post, void *data);


static ngx_uint_t                 ngx_event_max_module;

ngx_uint_t                        ngx_event_flags;
ngx_event_actions_t               ngx_event_actions;


ngx_atomic_t                      connection_counter;
ngx_atomic_t                     *ngx_connection_counter = &connection_counter;


ngx_atomic_t                     *ngx_accept_mutex_ptr;
ngx_atomic_t                     *ngx_accept_mutex;
ngx_uint_t                        ngx_accept_mutex_held;
ngx_msec_t                        ngx_accept_mutex_delay;
ngx_int_t                         ngx_accept_disabled;


#if (NGX_STAT_STUB)

ngx_atomic_t   ngx_stat_accepted0;
ngx_atomic_t  *ngx_stat_accepted = &ngx_stat_accepted0;
ngx_atomic_t   ngx_stat_requests0;
ngx_atomic_t  *ngx_stat_requests = &ngx_stat_requests0;
ngx_atomic_t   ngx_stat_active0;
ngx_atomic_t  *ngx_stat_active = &ngx_stat_active0;
ngx_atomic_t   ngx_stat_reading0;
ngx_atomic_t  *ngx_stat_reading = &ngx_stat_reading0;
ngx_atomic_t   ngx_stat_writing0;
ngx_atomic_t  *ngx_stat_writing = &ngx_stat_reading0;

#endif



static ngx_command_t  ngx_events_commands[] = {

    { ngx_string("events"),
      NGX_MAIN_CONF|NGX_CONF_BLOCK|NGX_CONF_NOARGS,
      ngx_events_block,
      0,
      0,
      NULL },

      ngx_null_command
};

    
static ngx_core_module_t  ngx_events_module_ctx = {
    ngx_string("events"),
    NULL,
    NULL
};  


ngx_module_t  ngx_events_module = {
    NGX_MODULE,
    &ngx_events_module_ctx,                /* module context */
    ngx_events_commands,                   /* module directives */
    NGX_CORE_MODULE,                       /* module type */
    NULL,                                  /* init module */
    NULL                                   /* init process */
};


static ngx_str_t  event_core_name = ngx_string("event_core");

static ngx_conf_post_t  ngx_accept_mutex_post = { ngx_accept_mutex_check } ;


static ngx_command_t  ngx_event_core_commands[] = {

    { ngx_string("connections"),
      NGX_EVENT_CONF|NGX_CONF_TAKE1,
      ngx_event_connections,
      0,
      0,
      NULL },

    { ngx_string("use"),
      NGX_EVENT_CONF|NGX_CONF_TAKE1,
      ngx_event_use,
      0,
      0,
      NULL },

    { ngx_string("multi_accept"),
      NGX_EVENT_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_flag_slot,
      0,
      offsetof(ngx_event_conf_t, multi_accept),
      NULL },

    { ngx_string("accept_mutex"),
      NGX_EVENT_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_flag_slot,
      0,
      offsetof(ngx_event_conf_t, accept_mutex),
      &ngx_accept_mutex_post },

    { ngx_string("accept_mutex_delay"),
      NGX_EVENT_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_msec_slot,
      0,
      offsetof(ngx_event_conf_t, accept_mutex_delay),
      NULL },

    { ngx_string("debug_connection"),
      NGX_EVENT_CONF|NGX_CONF_TAKE1,
      ngx_event_debug_connection,
      0,
      0,
      NULL },

      ngx_null_command
};


ngx_event_module_t  ngx_event_core_module_ctx = {
    &event_core_name,
    ngx_event_create_conf,                 /* create configuration */
    ngx_event_init_conf,                   /* init configuration */

    { NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL }
};


ngx_module_t  ngx_event_core_module = {
    NGX_MODULE,
    &ngx_event_core_module_ctx,            /* module context */
    ngx_event_core_commands,               /* module directives */
    NGX_EVENT_MODULE,                      /* module type */
    ngx_event_module_init,                 /* init module */
    ngx_event_process_init                 /* init process */
};


static ngx_int_t ngx_event_module_init(ngx_cycle_t *cycle)
{
#if !(NGX_WIN32)

    size_t               size;
    void              ***cf;
    char                *shared;
    ngx_core_conf_t     *ccf;
    ngx_event_conf_t    *ecf;

    cf = ngx_get_conf(cycle->conf_ctx, ngx_events_module);

    if (cf == NULL) {
        ngx_log_error(NGX_LOG_EMERG, cycle->log, 0,
                      "no \"events\" section in configuration");
        return NGX_ERROR;
    }

    ecf = (*cf)[ngx_event_core_module.ctx_index];

    ngx_log_error(NGX_LOG_INFO, cycle->log, 0,
                  "using the \"%s\" event method", ecf->name);


    ccf = (ngx_core_conf_t *) ngx_get_conf(cycle->conf_ctx, ngx_core_module);

    if (ccf->master == 0 || ngx_accept_mutex_ptr) {
        return NGX_OK;
    }


    /* TODO: adjust cache line size, 128 is P4 cache line size */

    size = 128            /* ngx_accept_mutex */
           + 128;         /* ngx_connection_counter */

#if (NGX_STAT_STUB)

    size += 128           /* ngx_stat_accepted */
           + 128          /* ngx_stat_requests */
           + 128          /* ngx_stat_active */
           + 128          /* ngx_stat_reading */
           + 128;         /* ngx_stat_writing */

#endif

    if (!(shared = ngx_create_shared_memory(size, cycle->log))) {
        return NGX_ERROR;
    }

    ngx_accept_mutex_ptr = (ngx_atomic_t *) shared;
    ngx_connection_counter = (ngx_atomic_t *) (shared + 128);

#if (NGX_STAT_STUB)

    ngx_stat_accepted = (ngx_atomic_t *) (shared + 2 * 128);
    ngx_stat_requests = (ngx_atomic_t *) (shared + 3 * 128);
    ngx_stat_active = (ngx_atomic_t *) (shared + 4 * 128);
    ngx_stat_reading = (ngx_atomic_t *) (shared + 5 * 128);
    ngx_stat_writing = (ngx_atomic_t *) (shared + 6 * 128);

#endif

    ngx_log_debug2(NGX_LOG_DEBUG_EVENT, cycle->log, 0,
                   "counter: %p, %d",
                   ngx_connection_counter, *ngx_connection_counter);

#endif

    return NGX_OK;
}


static ngx_int_t ngx_event_process_init(ngx_cycle_t *cycle)
{
    ngx_uint_t           m, i;
    ngx_socket_t         fd;
    ngx_event_t         *rev, *wev;
    ngx_listening_t     *s;
    ngx_connection_t    *c;
    ngx_core_conf_t     *ccf;
    ngx_event_conf_t    *ecf;
    ngx_event_module_t  *module;
#if (NGX_WIN32)
    ngx_iocp_conf_t     *iocpcf;
#endif

    ccf = (ngx_core_conf_t *) ngx_get_conf(cycle->conf_ctx, ngx_core_module);
    ecf = ngx_event_get_conf(cycle->conf_ctx, ngx_event_core_module);

    if (ngx_accept_mutex_ptr && ccf->worker_processes > 1 && ecf->accept_mutex)
    {
        ngx_accept_mutex = ngx_accept_mutex_ptr;
        ngx_accept_mutex_held = 0;
        ngx_accept_mutex_delay = ecf->accept_mutex_delay;
    }

#if (NGX_THREADS)
    if (!(ngx_posted_events_mutex = ngx_mutex_init(cycle->log, 0))) {
        return NGX_ERROR;
    }
#endif

    if (ngx_event_timer_init(cycle->log) == NGX_ERROR) {
        return NGX_ERROR;
    }

    cycle->connection_n = ecf->connections;

    for (m = 0; ngx_modules[m]; m++) {
        if (ngx_modules[m]->type != NGX_EVENT_MODULE) {
            continue;
        }

        if (ngx_modules[m]->ctx_index == ecf->use) {
            module = ngx_modules[m]->ctx;
            if (module->actions.init(cycle) == NGX_ERROR) {
                /* fatal */
                exit(2);
            }
            break;
        }
    }

    cycle->connections = ngx_alloc(sizeof(ngx_connection_t) * ecf->connections,
                                   cycle->log);
    if (cycle->connections == NULL) {
        return NGX_ERROR;
    }

    c = cycle->connections;
    for (i = 0; i < cycle->connection_n; i++) {
        c[i].fd = (ngx_socket_t) -1;
        c[i].data = NULL;
#if (NGX_THREADS)
        c[i].lock = 0;
#endif
    }

    cycle->read_events = ngx_alloc(sizeof(ngx_event_t) * ecf->connections,
                                   cycle->log);
    if (cycle->read_events == NULL) {
        return NGX_ERROR;
    }

    rev = cycle->read_events;
    for (i = 0; i < cycle->connection_n; i++) {
        rev[i].closed = 1;
        rev[i].instance = 1;
#if (NGX_THREADS)
        rev[i].lock = &c[i].lock;
        rev[i].own_lock = &c[i].lock;
#endif
    }

    cycle->write_events = ngx_alloc(sizeof(ngx_event_t) * ecf->connections,
                                    cycle->log);
    if (cycle->write_events == NULL) {
        return NGX_ERROR;
    }

    wev = cycle->write_events;
    for (i = 0; i < cycle->connection_n; i++) {
        wev[i].closed = 1;
#if (NGX_THREADS)
        wev[i].lock = &c[i].lock;
        wev[i].own_lock = &c[i].lock;
#endif
    }

    /* for each listening socket */

    s = cycle->listening.elts;
    for (i = 0; i < cycle->listening.nelts; i++) {

        fd = s[i].fd;

#if (NGX_WIN32)
        /*
         * Winsock assignes a socket number divisible by 4
         * so to find a connection we divide a socket number by 4.
         */

        fd /= 4;
#endif

        c = &cycle->connections[fd];
        rev = &cycle->read_events[fd];
        wev = &cycle->write_events[fd];

        ngx_memzero(c, sizeof(ngx_connection_t));
        ngx_memzero(rev, sizeof(ngx_event_t));
        ngx_memzero(wev, sizeof(ngx_event_t));

        c->fd = s[i].fd;
        c->listening = &s[i];

        c->ctx = s[i].ctx;
        c->servers = s[i].servers;
        c->log = s[i].log;
        c->read = rev;

        /* required by iocp in "c->write->active = 1" */
        c->write = wev;

        /* required by poll */
        wev->index = NGX_INVALID_INDEX;

        rev->log = c->log;
        rev->data = c;
        rev->index = NGX_INVALID_INDEX;

        rev->available = 0;

        rev->accept = 1;

#if (NGX_HAVE_DEFERRED_ACCEPT)
        rev->deferred_accept = s[i].deferred_accept;
#endif

        if (!(ngx_event_flags & NGX_USE_IOCP_EVENT)) {
            if (s[i].remain) {

                /*
                 * delete the old accept events that were bound to
                 * the old cycle read events array
                 */

                if (ngx_del_event(&cycle->old_cycle->read_events[fd],
                                 NGX_READ_EVENT, NGX_CLOSE_EVENT) == NGX_ERROR)
                {
                    return NGX_ERROR;
                }

                cycle->old_cycle->connections[fd].fd = (ngx_socket_t) -1;
            }
        }

#if (NGX_WIN32)

        if (ngx_event_flags & NGX_USE_IOCP_EVENT) {
            rev->event_handler = ngx_event_acceptex;

            if (ngx_add_event(rev, 0, NGX_IOCP_ACCEPT) == NGX_ERROR) {
                return NGX_ERROR;
            }

            iocpcf = ngx_event_get_conf(cycle->conf_ctx, ngx_iocp_module);
            if (ngx_event_post_acceptex(&s[i], iocpcf->post_acceptex)
                                                                  == NGX_ERROR)
            {
                return NGX_ERROR;
            }

        } else {
            rev->event_handler = ngx_event_accept;

            if (ngx_add_event(rev, NGX_READ_EVENT, 0) == NGX_ERROR) {
                return NGX_ERROR;
            }
        }

#else

        rev->event_handler = ngx_event_accept;

        if (ngx_accept_mutex) {
            continue;
        }

        if (ngx_event_flags & NGX_USE_RTSIG_EVENT) {
            if (ngx_add_conn(c) == NGX_ERROR) {
                return NGX_ERROR;
            }

        } else {
            if (ngx_add_event(rev, NGX_READ_EVENT, 0) == NGX_ERROR) {
                return NGX_ERROR;
            }
        }

#endif
    }

    return NGX_OK;
}


ngx_int_t ngx_send_lowat(ngx_connection_t *c, size_t lowat)
{
    int  sndlowat;

#if (NGX_HAVE_LOWAT_EVENT)

    if (ngx_event_flags & NGX_USE_KQUEUE_EVENT) {
        c->write->available = lowat;
        return NGX_OK;
    }

#endif
    
    if (lowat == 0 || c->sndlowat) {
        return NGX_OK;
    }

    sndlowat = (int) lowat;

    if (setsockopt(c->fd, SOL_SOCKET, SO_SNDLOWAT,
                                  (const void *) &sndlowat, sizeof(int)) == -1)
    {
        ngx_connection_error(c, ngx_socket_errno,
                             "setsockopt(SO_SNDLOWAT) failed");
        return NGX_ERROR;
    }

    c->sndlowat = 1;

    return NGX_OK;
}


static char *ngx_events_block(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
    int                    m;
    char                  *rv;
    void               ***ctx;
    ngx_conf_t            pcf;
    ngx_event_module_t   *module;

    /* count the number of the event modules and set up their indices */

    ngx_event_max_module = 0;
    for (m = 0; ngx_modules[m]; m++) {
        if (ngx_modules[m]->type != NGX_EVENT_MODULE) {
            continue;
        }

        ngx_modules[m]->ctx_index = ngx_event_max_module++;
    }

    ngx_test_null(ctx, ngx_pcalloc(cf->pool, sizeof(void *)), NGX_CONF_ERROR);

    ngx_test_null(*ctx,
                  ngx_pcalloc(cf->pool, ngx_event_max_module * sizeof(void *)),
                  NGX_CONF_ERROR);

    *(void **) conf = ctx;

    for (m = 0; ngx_modules[m]; m++) {
        if (ngx_modules[m]->type != NGX_EVENT_MODULE) {
            continue;
        }

        module = ngx_modules[m]->ctx;

        if (module->create_conf) {
            ngx_test_null((*ctx)[ngx_modules[m]->ctx_index],
                          module->create_conf(cf->cycle),
                          NGX_CONF_ERROR);
        }
    }

    pcf = *cf;
    cf->ctx = ctx;
    cf->module_type = NGX_EVENT_MODULE;
    cf->cmd_type = NGX_EVENT_CONF;
    rv = ngx_conf_parse(cf, NULL);
    *cf = pcf;

    if (rv != NGX_CONF_OK)
        return rv;

    for (m = 0; ngx_modules[m]; m++) {
        if (ngx_modules[m]->type != NGX_EVENT_MODULE) {
            continue;
        }

        module = ngx_modules[m]->ctx;

        if (module->init_conf) {
            rv = module->init_conf(cf->cycle,
                                   (*ctx)[ngx_modules[m]->ctx_index]);
            if (rv != NGX_CONF_OK) {
                return rv;
            }
        }
    }

    return NGX_CONF_OK;
}


static char *ngx_event_connections(ngx_conf_t *cf, ngx_command_t *cmd,
                                   void *conf)
{
    ngx_event_conf_t  *ecf = conf;

    ngx_str_t  *value;

    if (ecf->connections != NGX_CONF_UNSET_UINT) {
        return "is duplicate" ;
    }

    value = cf->args->elts;
    ecf->connections = ngx_atoi(value[1].data, value[1].len);
    if (ecf->connections == (ngx_uint_t) NGX_ERROR) {
        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                           "invalid number \"%V\"", &value[1]);

        return NGX_CONF_ERROR;
    }

    cf->cycle->connection_n = ecf->connections;

    return NGX_CONF_OK;
}


static char *ngx_event_use(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
    ngx_event_conf_t  *ecf = conf;

    ngx_int_t             m;
    ngx_str_t            *value;
    ngx_event_conf_t     *old_ecf;
    ngx_event_module_t   *module;

    if (ecf->use != NGX_CONF_UNSET_UINT) {
        return "is duplicate" ;
    }

    value = cf->args->elts;

    if (cf->cycle->old_cycle->conf_ctx) {
        old_ecf = ngx_event_get_conf(cf->cycle->old_cycle->conf_ctx,
                                     ngx_event_core_module);
    } else {
        old_ecf = NULL;
    }


    for (m = 0; ngx_modules[m]; m++) {
        if (ngx_modules[m]->type != NGX_EVENT_MODULE) {
            continue;
        }

        module = ngx_modules[m]->ctx;
        if (module->name->len == value[1].len) {
            if (ngx_strcmp(module->name->data, value[1].data) == 0) {
                ecf->use = ngx_modules[m]->ctx_index;
                ecf->name = module->name->data;

                if (ngx_process == NGX_PROCESS_SINGLE
                    && old_ecf
                    && old_ecf->use != ecf->use)
                {
                    ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                               "when the server runs without a master process "
                               "the \"%V\" event type must be the same as "
                               "in previous configuration - \"%s\" "
                               "and it can not be changed on the fly, "
                               "to change it you need to stop server "
                               "and start it again",
                               &value[1], old_ecf->name);

                    return NGX_CONF_ERROR;
                }

                return NGX_CONF_OK;
            }
        }
    }

    ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                       "invalid event type \"%V\"", &value[1]);

    return NGX_CONF_ERROR;
}


static char *ngx_event_debug_connection(ngx_conf_t *cf, ngx_command_t *cmd,
                                        void *conf)
{
#if (NGX_DEBUG)
    ngx_event_conf_t  *ecf = conf;

    in_addr_t       *addr;
    ngx_str_t       *value;
    struct hostent  *h;

    value = cf->args->elts;

    /* AF_INET only */

    if (!(addr = ngx_push_array(&ecf->debug_connection))) {
        return NGX_CONF_ERROR;
    }

    *addr = inet_addr((char *) value[1].data);

    if (*addr != INADDR_NONE) {
        return NGX_OK;
    }

    h = gethostbyname((char *) value[1].data);

    if (h == NULL || h->h_addr_list[0] == NULL) {
        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                           "host \"%s\" not found", value[1].data);
        return NGX_CONF_ERROR;
    }

    *addr = *(in_addr_t *)(h->h_addr_list[0]);

#else

    ngx_conf_log_error(NGX_LOG_WARN, cf, 0,
                       "\"debug_connection\" is ignored, you need to rebuild "
                       "nginx using --with-debug option to enable it");

#endif

    return NGX_OK;
}


static void *ngx_event_create_conf(ngx_cycle_t *cycle)
{
    ngx_event_conf_t  *ecf;

    ngx_test_null(ecf, ngx_palloc(cycle->pool, sizeof(ngx_event_conf_t)),
                  NGX_CONF_ERROR);

    ecf->connections = NGX_CONF_UNSET_UINT;
    ecf->use = NGX_CONF_UNSET_UINT;
    ecf->multi_accept = NGX_CONF_UNSET;
    ecf->accept_mutex = NGX_CONF_UNSET;
    ecf->accept_mutex_delay = NGX_CONF_UNSET_MSEC;
    ecf->name = (void *) NGX_CONF_UNSET;

#if (NGX_DEBUG)
    ngx_init_array(ecf->debug_connection, cycle->pool, 5, sizeof(in_addr_t),
                   NGX_CONF_ERROR);
#endif

    return ecf;
}


static char *ngx_event_init_conf(ngx_cycle_t *cycle, void *conf)
{
    ngx_event_conf_t  *ecf = conf;

    int                  fd, rtsig;
    ngx_int_t            i, connections;
    ngx_module_t        *module;
    ngx_core_conf_t     *ccf;
    ngx_event_module_t  *event_module;

    connections = NGX_CONF_UNSET_UINT;
    module = NULL;
    rtsig = 0;
    fd = 0;

#if (NGX_HAVE_EPOLL) && !(NGX_TEST_BUILD_EPOLL)

    fd = epoll_create(100);

    if (fd != -1) {
        close(fd);
        connections = DEFAULT_CONNECTIONS;
        module = &ngx_epoll_module;

    } else if (ngx_errno != NGX_ENOSYS) {
        connections = DEFAULT_CONNECTIONS;
        module = &ngx_epoll_module;
    }

#endif

#if (NGX_HAVE_RTSIG)

    if (module == NULL) {
        connections = DEFAULT_CONNECTIONS;
        module = &ngx_rtsig_module;
        rtsig = 1;
    }

#endif

#if (NGX_HAVE_DEVPOLL)

    connections = DEFAULT_CONNECTIONS;
    module = &ngx_devpoll_module;

#endif

#if (NGX_HAVE_KQUEUE)

    connections = DEFAULT_CONNECTIONS;
    module = &ngx_kqueue_module;

#endif

#if (NGX_HAVE_SELECT)

    if (module == NULL) {

#if (NGX_WIN32)
        connections = DEFAULT_CONNECTIONS;
#else
        connections = FD_SETSIZE < DEFAULT_CONNECTIONS ? FD_SETSIZE:
                                                         DEFAULT_CONNECTIONS;
#endif
        module = &ngx_select_module;
    }

#endif

    if (module == NULL) {
        for (i = 0; ngx_modules[i]; i++) {
            if (ngx_modules[i]->type == NGX_EVENT_MODULE) {
                event_module = ngx_modules[i]->ctx;

                if (ngx_strcmp(event_module->name->data, event_core_name.data)
                                                                          == 0)
                {
                    continue;
                }

                module = ngx_modules[i];
                break;
            }
        }
    }

    if (module == NULL) {
        ngx_log_error(NGX_LOG_EMERG, cycle->log, 0, "no events module found");
        return NGX_CONF_ERROR;
    }

    ngx_conf_init_unsigned_value(ecf->connections, connections);
    cycle->connection_n = ecf->connections;

    ngx_conf_init_unsigned_value(ecf->use, module->ctx_index);

    event_module = module->ctx;
    ngx_conf_init_ptr_value(ecf->name, event_module->name->data);

    ngx_conf_init_value(ecf->multi_accept, 0);
    ngx_conf_init_value(ecf->accept_mutex, 1);
    ngx_conf_init_msec_value(ecf->accept_mutex_delay, 500);


    if (!rtsig || ecf->accept_mutex) {
        return NGX_CONF_OK;
    }

    ccf = (ngx_core_conf_t *) ngx_get_conf(cycle->conf_ctx, ngx_core_module);

    if (ccf->worker_processes == 0) {
        return NGX_CONF_OK;
    }

    ngx_log_error(NGX_LOG_EMERG, cycle->log, 0,
                  "the \"rtsig\" method requires \"accept_mutex\" to be on");

    return NGX_CONF_ERROR;
}


static char *ngx_accept_mutex_check(ngx_conf_t *cf, void *post, void *data)
{
#if !(NGX_HAVE_ATOMIC_OPS)

    ngx_flag_t *fp = data;

    *fp = 0;

    ngx_conf_log_error(NGX_LOG_WARN, cf, 0,
                       "\"accept_mutex\" is not supported, ignored");

#endif

    return NGX_CONF_OK;
}