ngx_event.c

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/*
 * 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_eventport_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 ngx_uint_t     ngx_timer_resolution;
sig_atomic_t          ngx_event_timer_alarm;

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 = 1;
ngx_atomic_t         *ngx_connection_counter = &connection_counter;


ngx_atomic_t         *ngx_accept_mutex_ptr;
ngx_shmtx_t           ngx_accept_mutex;
ngx_uint_t            ngx_use_accept_mutex;
ngx_uint_t            ngx_accept_events;
ngx_uint_t            ngx_accept_mutex_held;
ngx_msec_t            ngx_accept_mutex_delay;
ngx_int_t             ngx_accept_disabled;
ngx_file_t            ngx_accept_mutex_lock_file;


#if (NGX_STAT_STUB)

ngx_atomic_t   ngx_stat_accepted0;
ngx_atomic_t  *ngx_stat_accepted = &ngx_stat_accepted0;
ngx_atomic_t   ngx_stat_handled0;
ngx_atomic_t  *ngx_stat_handled = &ngx_stat_handled0;
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_writing0;

#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_V1,
    &ngx_events_module_ctx,                /* module context */
    ngx_events_commands,                   /* module directives */
    NGX_CORE_MODULE,                       /* module type */
    NULL,                                  /* init master */
    NULL,                                  /* init module */
    NULL,                                  /* init process */
    NULL,                                  /* init thread */
    NULL,                                  /* exit thread */
    NULL,                                  /* exit process */
    NULL,                                  /* exit master */
    NGX_MODULE_V1_PADDING
};


static ngx_str_t  event_core_name = ngx_string("event_core");


static ngx_command_t  ngx_event_core_commands[] = {

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

    { 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_FLAG,
      ngx_conf_set_flag_slot,
      0,
      offsetof(ngx_event_conf_t, multi_accept),
      NULL },

    { ngx_string("accept_mutex"),
      NGX_EVENT_CONF|NGX_CONF_FLAG,
      ngx_conf_set_flag_slot,
      0,
      offsetof(ngx_event_conf_t, accept_mutex),
      NULL },

    { 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_V1,
    &ngx_event_core_module_ctx,            /* module context */
    ngx_event_core_commands,               /* module directives */
    NGX_EVENT_MODULE,                      /* module type */
    NULL,                                  /* init master */
    ngx_event_module_init,                 /* init module */
    ngx_event_process_init,                /* init process */
    NULL,                                  /* init thread */
    NULL,                                  /* exit thread */
    NULL,                                  /* exit process */
    NULL,                                  /* exit master */
    NGX_MODULE_V1_PADDING
};


void
ngx_process_events_and_timers(ngx_cycle_t *cycle)
{
    ngx_uint_t  flags;
    ngx_msec_t  timer, delta;

    if (ngx_timer_resolution) {
        timer = NGX_TIMER_INFINITE;
        flags = 0;

    } else {
        timer = ngx_event_find_timer();
        flags = NGX_UPDATE_TIME;

#if (NGX_THREADS)

        if (timer == NGX_TIMER_INFINITE || timer > 500) {
            timer = 500;
        }

#endif
    }

    if (ngx_use_accept_mutex) {
        if (ngx_accept_disabled > 0) {
            ngx_accept_disabled--;

        } else {
            if (ngx_trylock_accept_mutex(cycle) == NGX_ERROR) {
                return;
            }

            if (ngx_accept_mutex_held) {
                flags |= NGX_POST_EVENTS;

            } else {
                if (timer == NGX_TIMER_INFINITE
                    || timer > ngx_accept_mutex_delay)
                {
                    timer = ngx_accept_mutex_delay;
                }
            }
        }
    }

    delta = ngx_current_msec;

    (void) ngx_process_events(cycle, timer, flags);

    delta = ngx_current_msec - delta;

    ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0,
                   "timer delta: %M", delta);

    if (ngx_posted_accept_events) {
        ngx_event_process_posted(cycle, &ngx_posted_accept_events);
    }

    if (ngx_accept_mutex_held) {
        ngx_shmtx_unlock(&ngx_accept_mutex);
    }

    if (delta) {
        ngx_event_expire_timers();
    }

    ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0,
                   "posted events %p", ngx_posted_events);

    if (ngx_posted_events) {
        if (ngx_threaded) {
            ngx_wakeup_worker_thread(cycle);

        } else {
            ngx_event_process_posted(cycle, &ngx_posted_events);
        }
    }
}


ngx_int_t
ngx_handle_read_event(ngx_event_t *rev, ngx_uint_t flags)
{
    if (ngx_event_flags & NGX_USE_CLEAR_EVENT) {

        /* kqueue, epoll */

        if (!rev->active && !rev->ready) {
            if (ngx_add_event(rev, NGX_READ_EVENT, NGX_CLEAR_EVENT)
                == NGX_ERROR)
            {
                return NGX_ERROR;
            }
        }

        return NGX_OK;

    } else if (ngx_event_flags & NGX_USE_LEVEL_EVENT) {

        /* select, poll, /dev/poll */

        if (!rev->active && !rev->ready) {
            if (ngx_add_event(rev, NGX_READ_EVENT, NGX_LEVEL_EVENT)
                == NGX_ERROR)
            {
                return NGX_ERROR;
            }

            return NGX_OK;
        }

        if (rev->active && (rev->ready || (flags & NGX_CLOSE_EVENT))) {
            if (ngx_del_event(rev, NGX_READ_EVENT, NGX_LEVEL_EVENT | flags)
                == NGX_ERROR)
            {
                return NGX_ERROR;
            }

            return NGX_OK;
        }

    } else if (ngx_event_flags & NGX_USE_EVENTPORT_EVENT) {

        /* event ports */

        if (!rev->active && !rev->ready) {
            if (ngx_add_event(rev, NGX_READ_EVENT, 0) == NGX_ERROR) {
                return NGX_ERROR;
            }

            return NGX_OK;
        }

        if (rev->oneshot && !rev->ready) {
            if (ngx_del_event(rev, NGX_READ_EVENT, 0) == NGX_ERROR) {
                return NGX_ERROR;
            }

            return NGX_OK;
        }
    }

    /* aio, iocp, rtsig */

    return NGX_OK;
}


ngx_int_t
ngx_handle_write_event(ngx_event_t *wev, size_t lowat)
{
    ngx_connection_t  *c;

    if (lowat) {
        c = wev->data;

        if (ngx_send_lowat(c, lowat) == NGX_ERROR) {
            return NGX_ERROR;
        }
    }

    if (ngx_event_flags & NGX_USE_CLEAR_EVENT) {

        /* kqueue, epoll */

        if (!wev->active && !wev->ready) {
            if (ngx_add_event(wev, NGX_WRITE_EVENT,
                              NGX_CLEAR_EVENT | (lowat ? NGX_LOWAT_EVENT : 0))
                == NGX_ERROR)
            {
                return NGX_ERROR;
            }
        }

        return NGX_OK;

    } else if (ngx_event_flags & NGX_USE_LEVEL_EVENT) {

        /* select, poll, /dev/poll */

        if (!wev->active && !wev->ready) {
            if (ngx_add_event(wev, NGX_WRITE_EVENT, NGX_LEVEL_EVENT)
                == NGX_ERROR)
            {
                return NGX_ERROR;
            }

            return NGX_OK;
        }

        if (wev->active && wev->ready) {
            if (ngx_del_event(wev, NGX_WRITE_EVENT, NGX_LEVEL_EVENT)
                == NGX_ERROR)
            {
                return NGX_ERROR;
            }

            return NGX_OK;
        }

    } else if (ngx_event_flags & NGX_USE_EVENTPORT_EVENT) {

        /* event ports */

        if (!wev->active && !wev->ready) {
            if (ngx_add_event(wev, NGX_WRITE_EVENT, 0) == NGX_ERROR) {
                return NGX_ERROR;
            }

            return NGX_OK;
        }

        if (wev->oneshot && wev->ready) {
            if (ngx_del_event(wev, NGX_WRITE_EVENT, 0) == NGX_ERROR) {
                return NGX_ERROR;
            }

            return NGX_OK;
        }
    }

    /* aio, iocp, rtsig */

    return NGX_OK;
}