Nginx学习笔记之事件驱动框架处理流程

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Nginx学习笔记之事件驱动框架处理流程

void
ngx_event_accept(ngx_event_t *ev)
{
 socklen_t  socklen;
 ngx_err_t  err;
 ngx_log_t  *log;
 ngx_uint_t  level;
 ngx_socket_t  s;
 ngx_event_t  *rev, *wev;
 ngx_listening_t  *ls;
 ngx_connection_t *c, *lc;
 ngx_event_conf_t *ecf;
 u_char  sa[NGX_SOCKADDRLEN];
 
 if (ev->timedout) {
  if (ngx_enable_accept_events((ngx_cycle_t *) ngx_cycle) !=NGX_OK) {
   return;
  }
 
  ev->timedout=0;
 }
 
 ecf=ngx_event_get_conf(ngx_cycle->conf_ctx, ngx_event_core_module);
 
 if (ngx_event_flags & NGX_USE_RTSIG_EVENT) {
  ev->available=1;
 
 } else if (!(ngx_event_flags & NGX_USE_KQUEUE_EVENT)) {
  ev->available=ecf->multi_accept;
 }
 
 lc=ev->data;
 ls=lc->listening;
 ev->ready=0;
 
 do {
  socklen=NGX_SOCKADDRLEN;
 
  
  s=accept(lc->fd, (struct sockaddr *) sa, &socklen);
 
  if (s==(ngx_socket_t) -1)
  {
   err=ngx_socket_errno;
 
   if (err==NGX_EAGAIN)
   {
    
    return;
   }
 
   level=NGX_LOG_ALERT;
 
   if (err==NGX_ECONNABORTED) {
    level=NGX_LOG_ERR;
 
   } else if (err==NGX_EMFILE || err==NGX_ENFILE) {
    level=NGX_LOG_CRIT;
   }
 
   if (err==NGX_ECONNABORTED) {
    if (ngx_event_flags & NGX_USE_KQUEUE_EVENT) {
     ev->available--;
    }
 
    if (ev->available) {
     continue;
    }
   }
 
   if (err==NGX_EMFILE || err==NGX_ENFILE) {
    if (ngx_disable_accept_events((ngx_cycle_t *) ngx_cycle)
     !=NGX_OK)
    {
     return;
    }
 
    if (ngx_use_accept_mutex) {
     if (ngx_accept_mutex_held) {
      ngx_shmtx_unlock(&ngx_accept_mutex);
      ngx_accept_mutex_held=0;
     }
 
     ngx_accept_disabled=1;
 
    } else {
     ngx_add_timer(ev, ecf->accept_mutex_delay);
    }
   }
 
   return;
  }
 
  
  ngx_accept_disabled=ngx_cycle->connection_n / 8
        - ngx_cycle->free_connection_n;
 
  
  c=ngx_get_connection(s, ev->log);
 
  
  c->pool=ngx_create_pool(ls->pool_size, ev->log);
 
  c->sockaddr=ngx_palloc(c->pool, socklen);
 
  ngx_memcpy(c->sockaddr, sa, socklen);
 
  log=ngx_palloc(c->pool, sizeof(ngx_log_t));
 
  
  
  if (ngx_inherited_nonblocking) {
   if (ngx_event_flags & NGX_USE_AIO_EVENT) {
    if (ngx_blocking(s)==-1) {
     ngx_log_error(NGX_LOG_ALERT, ev->log, ngx_socket_errno,
         ngx_blocking_n " failed");
     ngx_close_accepted_connection(c);
     return;
    }
   }
 
  } else {
   if (!(ngx_event_flags & (NGX_USE_AIO_EVENT|NGX_USE_RTSIG_EVENT))) {
    if (ngx_nonblocking(s)==-1) {
     ngx_log_error(NGX_LOG_ALERT, ev->log, ngx_socket_errno,
         ngx_nonblocking_n " failed");
     ngx_close_accepted_connection(c);
     return;
    }
   }
  }
 
  *log=ls->log;
 
  c->recv=ngx_recv;
  c->send=ngx_send;
  c->recv_chain=ngx_recv_chain;
  c->send_chain=ngx_send_chain;
 
  c->log=log;
  c->pool->log=log;
 
  c->socklen=socklen;
  c->listening=ls;
  c->local_sockaddr=ls->sockaddr;
  c->local_socklen=ls->socklen;
 
  c->unexpected_eof=1;
 
  rev=c->read;
  wev=c->write;
 
  wev->ready=1;
 
  if (ngx_event_flags & (NGX_USE_AIO_EVENT|NGX_USE_RTSIG_EVENT)) {
   
   rev->ready=1;
  }
 
  if (ev->deferred_accept) {
   rev->ready=1;
 
  }
 
  rev->log=log;
  wev->log=log;
 
  
 
  c->number=ngx_atomic_fetch_add(ngx_connection_counter, 1);
 
  if (ls->addr_ntop) {
   c->addr_text.data=ngx_pnalloc(c->pool, ls->addr_text_max_len);
   if (c->addr_text.data==NULL) {
    ngx_close_accepted_connection(c);
    return;
   }
 
   c->addr_text.len=ngx_sock_ntop(c->sockaddr, c->socklen,
            c->addr_text.data,
            ls->addr_text_max_len, 0);
   if (c->addr_text.len==0) {
    ngx_close_accepted_connection(c);
    return;
   }
  }
 
  
  if (ngx_add_conn && (ngx_event_flags & NGX_USE_EPOLL_EVENT)==0) {
   if (ngx_add_conn(c)==NGX_ERROR) {
    ngx_close_accepted_connection(c);
    return;
   }
  }
 
  log->data=NULL;
  log->handler=NULL;
 
  
  ls->handler(c);
 
 } while (ev->available); 
}

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