text: 
  /*
   * Copyright (C) Igor Sysoev
   * Copyright (C) Nginx, Inc.
   */
  
  
  #include <ngx_config.h>
  #include <ngx_core.h>
  #include <ngx_http.h>
  
  
  static void ngx_http_wait_request_handler(ngx_event_t *ev);
  static ngx_http_request_t *ngx_http_alloc_request(ngx_connection_t *c);
  static void ngx_http_process_request_line(ngx_event_t *rev);
  static void ngx_http_process_request_headers(ngx_event_t *rev);
  static ssize_t ngx_http_read_request_header(ngx_http_request_t *r);
  static ngx_int_t ngx_http_alloc_large_header_buffer(ngx_http_request_t *r,
      ngx_uint_t request_line);
  
  static ngx_int_t ngx_http_process_header_line(ngx_http_request_t *r,
      ngx_table_elt_t *h, ngx_uint_t offset);
  static ngx_int_t ngx_http_process_unique_header_line(ngx_http_request_t *r,
      ngx_table_elt_t *h, ngx_uint_t offset);
  static ngx_int_t ngx_http_process_multi_header_lines(ngx_http_request_t *r,
      ngx_table_elt_t *h, ngx_uint_t offset);
  static ngx_int_t ngx_http_process_host(ngx_http_request_t *r,
      ngx_table_elt_t *h, ngx_uint_t offset);
  static ngx_int_t ngx_http_process_connection(ngx_http_request_t *r,
      ngx_table_elt_t *h, ngx_uint_t offset);
  static ngx_int_t ngx_http_process_user_agent(ngx_http_request_t *r,
      ngx_table_elt_t *h, ngx_uint_t offset);
  
  static ngx_int_t ngx_http_validate_host(ngx_str_t *host, ngx_pool_t *pool,
      ngx_uint_t alloc);
  static ngx_int_t ngx_http_set_virtual_server(ngx_http_request_t *r,
      ngx_str_t *host);
  static ngx_int_t ngx_http_find_virtual_server(ngx_connection_t *c,
      ngx_http_virtual_names_t *virtual_names, ngx_str_t *host,
      ngx_http_request_t *r, ngx_http_core_srv_conf_t **cscfp);
  
  static void ngx_http_request_handler(ngx_event_t *ev);
  static void ngx_http_terminate_request(ngx_http_request_t *r, ngx_int_t rc);
  static void ngx_http_terminate_handler(ngx_http_request_t *r);
  static void ngx_http_finalize_connection(ngx_http_request_t *r);
  static ngx_int_t ngx_http_set_write_handler(ngx_http_request_t *r);
  static void ngx_http_writer(ngx_http_request_t *r);
  static void ngx_http_request_finalizer(ngx_http_request_t *r);
  
  static void ngx_http_set_keepalive(ngx_http_request_t *r);
  static void ngx_http_keepalive_handler(ngx_event_t *ev);
  static void ngx_http_set_lingering_close(ngx_http_request_t *r);
  static void ngx_http_lingering_close_handler(ngx_event_t *ev);
  static ngx_int_t ngx_http_post_action(ngx_http_request_t *r);
  static void ngx_http_close_request(ngx_http_request_t *r, ngx_int_t error);
  static void ngx_http_log_request(ngx_http_request_t *r);
  
  static u_char *ngx_http_log_error(ngx_log_t *log, u_char *buf, size_t len);
  static u_char *ngx_http_log_error_handler(ngx_http_request_t *r,
      ngx_http_request_t *sr, u_char *buf, size_t len);
  
  #if (NGX_HTTP_SSL)
  static void ngx_http_ssl_handshake(ngx_event_t *rev);
  static void ngx_http_ssl_handshake_handler(ngx_connection_t *c);
  #endif
  
  
  static char *ngx_http_client_errors[] = {
  
      /* NGX_HTTP_PARSE_INVALID_METHOD */
      "client sent invalid method",
  
      /* NGX_HTTP_PARSE_INVALID_REQUEST */
      "client sent invalid request",
  
      /* NGX_HTTP_PARSE_INVALID_VERSION */
      "client sent invalid version",
  
      /* NGX_HTTP_PARSE_INVALID_09_METHOD */
      "client sent invalid method in HTTP/0.9 request"
  };
  
  // 请求头、在结构体的偏移和处理函数
  ngx_http_header_t  ngx_http_headers_in[] = {
      { ngx_string("Host"), offsetof(ngx_http_headers_in_t, host),
                   ngx_http_process_host },
  
      { ngx_string("Connection"), offsetof(ngx_http_headers_in_t, connection),
                   ngx_http_process_connection },
  
      { ngx_string("If-Modified-Since"),
                   offsetof(ngx_http_headers_in_t, if_modified_since),
                   ngx_http_process_unique_header_line },
  
      { ngx_string("If-Unmodified-Since"),
                   offsetof(ngx_http_headers_in_t, if_unmodified_since),
                   ngx_http_process_unique_header_line },
  
      { ngx_string("If-Match"),
                   offsetof(ngx_http_headers_in_t, if_match),
                   ngx_http_process_unique_header_line },
  
      { ngx_string("If-None-Match"),
                   offsetof(ngx_http_headers_in_t, if_none_match),
                   ngx_http_process_unique_header_line },
  
      { ngx_string("User-Agent"), offsetof(ngx_http_headers_in_t, user_agent),
                   ngx_http_process_user_agent },
  
      { ngx_string("Referer"), offsetof(ngx_http_headers_in_t, referer),
                   ngx_http_process_header_line },
  
      { ngx_string("Content-Length"),
                   offsetof(ngx_http_headers_in_t, content_length),
                   ngx_http_process_unique_header_line },
  
      { ngx_string("Content-Range"),
                   offsetof(ngx_http_headers_in_t, content_range),
                   ngx_http_process_unique_header_line },
  
      { ngx_string("Content-Type"),
                   offsetof(ngx_http_headers_in_t, content_type),
                   ngx_http_process_header_line },
  
      { ngx_string("Range"), offsetof(ngx_http_headers_in_t, range),
                   ngx_http_process_header_line },
  
      { ngx_string("If-Range"),
                   offsetof(ngx_http_headers_in_t, if_range),
                   ngx_http_process_unique_header_line },
  
      { ngx_string("Transfer-Encoding"),
                   offsetof(ngx_http_headers_in_t, transfer_encoding),
                   ngx_http_process_unique_header_line },
  
      { ngx_string("TE"),
                   offsetof(ngx_http_headers_in_t, te),
                   ngx_http_process_header_line },
  
      { ngx_string("Expect"),
                   offsetof(ngx_http_headers_in_t, expect),
                   ngx_http_process_unique_header_line },
  
      { ngx_string("Upgrade"),
                   offsetof(ngx_http_headers_in_t, upgrade),
                   ngx_http_process_header_line },
  
  #if (NGX_HTTP_GZIP || NGX_HTTP_HEADERS)
      { ngx_string("Accept-Encoding"),
                   offsetof(ngx_http_headers_in_t, accept_encoding),
                   ngx_http_process_header_line },
  
      { ngx_string("Via"), offsetof(ngx_http_headers_in_t, via),
                   ngx_http_process_header_line },
  #endif
  
      { ngx_string("Authorization"),
                   offsetof(ngx_http_headers_in_t, authorization),
                   ngx_http_process_unique_header_line },
  
      { ngx_string("Keep-Alive"), offsetof(ngx_http_headers_in_t, keep_alive),
                   ngx_http_process_header_line },
  
  #if (NGX_HTTP_X_FORWARDED_FOR)
      { ngx_string("X-Forwarded-For"),
                   offsetof(ngx_http_headers_in_t, x_forwarded_for),
                   ngx_http_process_multi_header_lines },
  #endif
  
  #if (NGX_HTTP_REALIP)
      { ngx_string("X-Real-IP"),
                   offsetof(ngx_http_headers_in_t, x_real_ip),
                   ngx_http_process_header_line },
  #endif
  
  #if (NGX_HTTP_HEADERS)
      { ngx_string("Accept"), offsetof(ngx_http_headers_in_t, accept),
                   ngx_http_process_header_line },
  
      { ngx_string("Accept-Language"),
                   offsetof(ngx_http_headers_in_t, accept_language),
                   ngx_http_process_header_line },
  #endif
  
  #if (NGX_HTTP_DAV)
      { ngx_string("Depth"), offsetof(ngx_http_headers_in_t, depth),
                   ngx_http_process_header_line },
  
      { ngx_string("Destination"), offsetof(ngx_http_headers_in_t, destination),
                   ngx_http_process_header_line },
  
      { ngx_string("Overwrite"), offsetof(ngx_http_headers_in_t, overwrite),
                   ngx_http_process_header_line },
  
      { ngx_string("Date"), offsetof(ngx_http_headers_in_t, date),
                   ngx_http_process_header_line },
  #endif
  
      { ngx_string("Cookie"), offsetof(ngx_http_headers_in_t, cookies),
                   ngx_http_process_multi_header_lines },
  
      { ngx_null_string, 0, NULL }
  };
  
  // 有连接到来时的处理函数
  void
  ngx_http_init_connection(ngx_connection_t *c)
  {
      ngx_uint_t              i;
      ngx_event_t            *rev;
      struct sockaddr_in     *sin;
      ngx_http_port_t        *port;
      ngx_http_in_addr_t     *addr;
      ngx_http_log_ctx_t     *ctx;
      ngx_http_connection_t  *hc;
  #if (NGX_HAVE_INET6)
      struct sockaddr_in6    *sin6;
      ngx_http_in6_addr_t    *addr6;
  #endif
  
      hc = ngx_pcalloc(c->pool, sizeof(ngx_http_connection_t));
      if (hc == NULL) {
          ngx_http_close_connection(c);
          return;
      }
  
      c->data = hc;
  
      /* find the server configuration for the address:port */
  
      port = c->listening->servers;
  
      if (port->naddrs > 1) {
  
          /*
           * there are several addresses on this port and one of them
           * is an "*:port" wildcard so getsockname() in ngx_http_server_addr()
           * is required to determine a server address
           */
  
          if (ngx_connection_local_sockaddr(c, NULL, 0) != NGX_OK) {
              ngx_http_close_connection(c);
              return;
          }
  
          switch (c->local_sockaddr->sa_family) {
  
  #if (NGX_HAVE_INET6)
          case AF_INET6:
              sin6 = (struct sockaddr_in6 *) c->local_sockaddr;
  
              addr6 = port->addrs;
  
              /* the last address is "*" */
  
              for (i = 0; i < port->naddrs - 1; i++) {
                  if (ngx_memcmp(&addr6[i].addr6, &sin6->sin6_addr, 16) == 0) {
                      break;
                  }
              }
  
              hc->addr_conf = &addr6[i].conf;
  
              break;
  #endif
  
          default: /* AF_INET */
              sin = (struct sockaddr_in *) c->local_sockaddr;
  
              addr = port->addrs;
  
              /* the last address is "*" */
  
              for (i = 0; i < port->naddrs - 1; i++) {
                  if (addr[i].addr == sin->sin_addr.s_addr) {
                      break;
                  }
              }
  
              hc->addr_conf = &addr[i].conf;
  
              break;
          }
  
      } else {
  
          switch (c->local_sockaddr->sa_family) {
  
  #if (NGX_HAVE_INET6)
          case AF_INET6:
              addr6 = port->addrs;
              hc->addr_conf = &addr6[0].conf;
              break;
  #endif
  
          default: /* AF_INET */
              addr = port->addrs;
              hc->addr_conf = &addr[0].conf;
              break;
          }
      }
  
      /* the default server configuration for the address:port */
      hc->conf_ctx = hc->addr_conf->default_server->ctx;
  
      ctx = ngx_palloc(c->pool, sizeof(ngx_http_log_ctx_t));
      if (ctx == NULL) {
          ngx_http_close_connection(c);
          return;
      }
  
      ctx->connection = c;
      ctx->request = NULL;
      ctx->current_request = NULL;
  
      c->log->connection = c->number;
      c->log->handler = ngx_http_log_error;
      c->log->data = ctx;
      c->log->action = "waiting for request";
  
      c->log_error = NGX_ERROR_INFO;
  
      rev = c->read;
      rev->handler = ngx_http_wait_request_handler;
      c->write->handler = ngx_http_empty_handler;
  
  #if (NGX_HTTP_V2)
      if (hc->addr_conf->http2) {
          rev->handler = ngx_http_v2_init;
      }
  #endif
  
  #if (NGX_HTTP_SSL)
      {
      ngx_http_ssl_srv_conf_t  *sscf;
  
      sscf = ngx_http_get_module_srv_conf(hc->conf_ctx, ngx_http_ssl_module);
  
      if (sscf->enable || hc->addr_conf->ssl) {
          hc->ssl = 1;
          c->log->action = "SSL handshaking";
          rev->handler = ngx_http_ssl_handshake;
      }
      }
  #endif
  
      if (hc->addr_conf->proxy_protocol) {
          hc->proxy_protocol = 1;
          c->log->action = "reading PROXY protocol";
      }
  
      if (rev->ready) {
          /* the deferred accept(), iocp */
  
          if (ngx_use_accept_mutex) {
              ngx_post_event(rev, &ngx_posted_events);
              return;
          }
  
          rev->handler(rev);
          return;
      }
      // 建立连接后，post_accept_timeout这么长时间还没有数据到来则超时
      ngx_add_timer(rev, c->listening->post_accept_timeout);
      ngx_reusable_connection(c, 1);
  
      if (ngx_handle_read_event(rev, 0) != NGX_OK) {
          ngx_http_close_connection(c);
          return;
      }
  }
  
  // 连接上有请求到来时的处理函数
  static void
  ngx_http_wait_request_handler(ngx_event_t *rev)
  {
      u_char                    *p;
      size_t                     size;
      ssize_t                    n;
      ngx_buf_t                 *b;
      ngx_connection_t          *c;
      ngx_http_connection_t     *hc;
      ngx_http_core_srv_conf_t  *cscf;
  
      c = rev->data;
  
      ngx_log_debug0(NGX_LOG_DEBUG_HTTP, c->log, 0, "http wait request handler");
      // 数据到来已经超时，关闭连接
      if (rev->timedout) {
          ngx_log_error(NGX_LOG_INFO, c->log, NGX_ETIMEDOUT, "client timed out");
          ngx_http_close_connection(c);
          return;
      }
      // 连接关闭了
      if (c->close) {
          ngx_http_close_connection(c);
          return;
      }
  
      hc = c->data;
      cscf = ngx_http_get_module_srv_conf(hc->conf_ctx, ngx_http_core_module);
      // 分配内存接收数据，如果需要的话
      size = cscf->client_header_buffer_size;
  
      b = c->buffer;
  
      if (b == NULL) {
          b = ngx_create_temp_buf(c->pool, size);
          if (b == NULL) {
              ngx_http_close_connection(c);
              return;
          }
  
          c->buffer = b;
  
      } else if (b->start == NULL) {
  
          b->start = ngx_palloc(c->pool, size);
          if (b->start == NULL) {
              ngx_http_close_connection(c);
              return;
          }
  
          b->pos = b->start;
          b->last = b->start;
          b->end = b->last + size;
      }
      // 接收数据
      n = c->recv(c, b->last, size);
  
      if (n == NGX_AGAIN) {
  
          if (!rev->timer_set) {
              ngx_add_timer(rev, c->listening->post_accept_timeout);
              ngx_reusable_connection(c, 1);
          }
  
          if (ngx_handle_read_event(rev, 0) != NGX_OK) {
              ngx_http_close_connection(c);
              return;
          }
  
          /*
           * We are trying to not hold c->buffer's memory for an idle connection.
           */
  
          if (ngx_pfree(c->pool, b->start) == NGX_OK) {
              b->start = NULL;
          }
  
          return;
      }
  
      if (n == NGX_ERROR) {
          ngx_http_close_connection(c);
          return;
      }
  
      if (n == 0) {
          ngx_log_error(NGX_LOG_INFO, c->log, 0,
                        "client closed connection");
          ngx_http_close_connection(c);
          return;
      }
      // 更新可写指针的位置
      b->last += n;
  
      if (hc->proxy_protocol) {
          hc->proxy_protocol = 0;
  
          p = ngx_proxy_protocol_read(c, b->pos, b->last);
  
          if (p == NULL) {
              ngx_http_close_connection(c);
              return;
          }
  
          b->pos = p;
  
          if (b->pos == b->last) {
              c->log->action = "waiting for request";
              b->pos = b->start;
              b->last = b->start;
              ngx_post_event(rev, &ngx_posted_events);
              return;
          }
      }
  
      c->log->action = "reading client request line";
  
      ngx_reusable_connection(c, 0);
  
      c->data = ngx_http_create_request(c);
      if (c->data == NULL) {
          ngx_http_close_connection(c);
          return;
      }
      // 准备处理请求
      rev->handler = ngx_http_process_request_line;
      ngx_http_process_request_line(rev);
  }
  
  
  ngx_http_request_t *
  ngx_http_create_request(ngx_connection_t *c)
  {
      ngx_http_request_t        *r;
      ngx_http_log_ctx_t        *ctx;
      ngx_http_core_loc_conf_t  *clcf;
      // 申请一个request结构体
      r = ngx_http_alloc_request(c);
      if (r == NULL) {
          return NULL;
      }
      // 本连接中的请求个数
      c->requests++;
  
      clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);
  
      ngx_set_connection_log(c, clcf->error_log);
  
      ctx = c->log->data;
      ctx->request = r;
      ctx->current_request = r;
  
  #if (NGX_STAT_STUB)
      (void) ngx_atomic_fetch_add(ngx_stat_reading, 1);
      r->stat_reading = 1;
      (void) ngx_atomic_fetch_add(ngx_stat_requests, 1);
  #endif
  
      return r;
  }
  
  // 申请一个request结构体
  static ngx_http_request_t *
  ngx_http_alloc_request(ngx_connection_t *c)
  {
      ngx_pool_t                 *pool;
      ngx_time_t                 *tp;
      ngx_http_request_t         *r;
      ngx_http_connection_t      *hc;
      ngx_http_core_srv_conf_t   *cscf;
      ngx_http_core_main_conf_t  *cmcf;
  
      hc = c->data;
  
      cscf = ngx_http_get_module_srv_conf(hc->conf_ctx, ngx_http_core_module);
  
      pool = ngx_create_pool(cscf->request_pool_size, c->log);
      if (pool == NULL) {
          return NULL;
      }
  
      r = ngx_pcalloc(pool, sizeof(ngx_http_request_t));
      if (r == NULL) {
          ngx_destroy_pool(pool);
          return NULL;
      }
  
      r->pool = pool;
  
      r->http_connection = hc;
      r->signature = NGX_HTTP_MODULE;
      r->connection = c;
  
      r->main_conf = hc->conf_ctx->main_conf;
      r->srv_conf = hc->conf_ctx->srv_conf;
      r->loc_conf = hc->conf_ctx->loc_conf;
  
      r->read_event_handler = ngx_http_block_reading;
  
      r->header_in = hc->busy ? hc->busy->buf : c->buffer;
  
      if (ngx_list_init(&r->headers_out.headers, r->pool, 20,
                        sizeof(ngx_table_elt_t))
          != NGX_OK)
      {
          ngx_destroy_pool(r->pool);
          return NULL;
      }
  
      if (ngx_list_init(&r->headers_out.trailers, r->pool, 4,
                        sizeof(ngx_table_elt_t))
          != NGX_OK)
      {
          ngx_destroy_pool(r->pool);
          return NULL;
      }
  
      r->ctx = ngx_pcalloc(r->pool, sizeof(void *) * ngx_http_max_module);
      if (r->ctx == NULL) {
          ngx_destroy_pool(r->pool);
          return NULL;
      }
  
      cmcf = ngx_http_get_module_main_conf(r, ngx_http_core_module);
  
      r->variables = ngx_pcalloc(r->pool, cmcf->variables.nelts
                                          * sizeof(ngx_http_variable_value_t));
      if (r->variables == NULL) {
          ngx_destroy_pool(r->pool);
          return NULL;
      }
  
  #if (NGX_HTTP_SSL)
      if (c->ssl) {
          r->main_filter_need_in_memory = 1;
      }
  #endif
  
      r->main = r;
      r->count = 1;
  
      tp = ngx_timeofday();
      r->start_sec = tp->sec;
      r->start_msec = tp->msec;
  
      r->method = NGX_HTTP_UNKNOWN;
      r->http_version = NGX_HTTP_VERSION_10;
  
      r->headers_in.content_length_n = -1;
      r->headers_in.keep_alive_n = -1;
      r->headers_out.content_length_n = -1;
      r->headers_out.last_modified_time = -1;
  
      r->uri_changes = NGX_HTTP_MAX_URI_CHANGES + 1;
      r->subrequests = NGX_HTTP_MAX_SUBREQUESTS + 1;
  
      r->http_state = NGX_HTTP_READING_REQUEST_STATE;
  
      r->log_handler = ngx_http_log_error_handler;
  
      return r;
  }
  
  
  #if (NGX_HTTP_SSL)
  
  static void
  ngx_http_ssl_handshake(ngx_event_t *rev)
  {
      u_char                    *p, buf[NGX_PROXY_PROTOCOL_MAX_HEADER + 1];
      size_t                     size;
      ssize_t                    n;
      ngx_err_t                  err;
      ngx_int_t                  rc;
      ngx_connection_t          *c;
      ngx_http_connection_t     *hc;
      ngx_http_ssl_srv_conf_t   *sscf;
      ngx_http_core_loc_conf_t  *clcf;
  
      c = rev->data;
      hc = c->data;
  
      ngx_log_debug0(NGX_LOG_DEBUG_HTTP, rev->log, 0,
                     "http check ssl handshake");
  
      if (rev->timedout) {
          ngx_log_error(NGX_LOG_INFO, c->log, NGX_ETIMEDOUT, "client timed out");
          ngx_http_close_connection(c);
          return;
      }
  
      if (c->close) {
          ngx_http_close_connection(c);
          return;
      }
  
      size = hc->proxy_protocol ? sizeof(buf) : 1;
  
      n = recv(c->fd, (char *) buf, size, MSG_PEEK);
  
      err = ngx_socket_errno;
  
      ngx_log_debug1(NGX_LOG_DEBUG_HTTP, rev->log, 0, "http recv(): %z", n);
  
      if (n == -1) {
          if (err == NGX_EAGAIN) {
              rev->ready = 0;
  
              if (!rev->timer_set) {
                  ngx_add_timer(rev, c->listening->post_accept_timeout);
                  ngx_reusable_connection(c, 1);
              }
  
              if (ngx_handle_read_event(rev, 0) != NGX_OK) {
                  ngx_http_close_connection(c);
              }
  
              return;
          }
  
          ngx_connection_error(c, err, "recv() failed");
          ngx_http_close_connection(c);
  
          return;
      }
  
      if (hc->proxy_protocol) {
          hc->proxy_protocol = 0;
  
          p = ngx_proxy_protocol_read(c, buf, buf + n);
  
          if (p == NULL) {
              ngx_http_close_connection(c);
              return;
          }
  
          size = p - buf;
  
          if (c->recv(c, buf, size) != (ssize_t) size) {
              ngx_http_close_connection(c);
              return;
          }
  
          c->log->action = "SSL handshaking";
  
          if (n == (ssize_t) size) {
              ngx_post_event(rev, &ngx_posted_events);
              return;
          }
  
          n = 1;
          buf[0] = *p;
      }
  
      if (n == 1) {
          if (buf[0] & 0x80 /* SSLv2 */ || buf[0] == 0x16 /* SSLv3/TLSv1 */) {
              ngx_log_debug1(NGX_LOG_DEBUG_HTTP, rev->log, 0,
                             "https ssl handshake: 0x%02Xd", buf[0]);
  
              clcf = ngx_http_get_module_loc_conf(hc->conf_ctx,
                                                  ngx_http_core_module);
  
              if (clcf->tcp_nodelay && ngx_tcp_nodelay(c) != NGX_OK) {
                  ngx_http_close_connection(c);
                  return;
              }
  
              sscf = ngx_http_get_module_srv_conf(hc->conf_ctx,
                                                  ngx_http_ssl_module);
  
              if (ngx_ssl_create_connection(&sscf->ssl, c, NGX_SSL_BUFFER)
                  != NGX_OK)
              {
                  ngx_http_close_connection(c);
                  return;
              }
  
              ngx_reusable_connection(c, 0);
  
              rc = ngx_ssl_handshake(c);
  
              if (rc == NGX_AGAIN) {
  
                  if (!rev->timer_set) {
                      ngx_add_timer(rev, c->listening->post_accept_timeout);
                  }
  
                  c->ssl->handler = ngx_http_ssl_handshake_handler;
                  return;
              }
  
              ngx_http_ssl_handshake_handler(c);
  
              return;
          }
  
          ngx_log_debug0(NGX_LOG_DEBUG_HTTP, rev->log, 0, "plain http");
  
          c->log->action = "waiting for request";
  
          rev->handler = ngx_http_wait_request_handler;
          ngx_http_wait_request_handler(rev);
  
          return;
      }
  
      ngx_log_error(NGX_LOG_INFO, c->log, 0, "client closed connection");
      ngx_http_close_connection(c);
  }
  
  
  static void
  ngx_http_ssl_handshake_handler(ngx_connection_t *c)
  {
      if (c->ssl->handshaked) {
  
          /*
           * The majority of browsers do not send the "close notify" alert.
           * Among them are MSIE, old Mozilla, Netscape 4, Konqueror,
           * and Links.  And what is more, MSIE ignores the server's alert.
           *
           * Opera and recent Mozilla send the alert.
           */
  
          c->ssl->no_wait_shutdown = 1;
  
  #if (NGX_HTTP_V2                                                              \
       && (defined TLSEXT_TYPE_application_layer_protocol_negotiation           \
           || defined TLSEXT_TYPE_next_proto_neg))
          {
          unsigned int            len;
          const unsigned char    *data;
          ngx_http_connection_t  *hc;
  
          hc = c->data;
  
          if (hc->addr_conf->http2) {
  
  #ifdef TLSEXT_TYPE_application_layer_protocol_negotiation
              SSL_get0_alpn_selected(c->ssl->connection, &data, &len);
  
  #ifdef TLSEXT_TYPE_next_proto_neg
              if (len == 0) {
                  SSL_get0_next_proto_negotiated(c->ssl->connection, &data, &len);
              }
  #endif
  
  #else /* TLSEXT_TYPE_next_proto_neg */
              SSL_get0_next_proto_negotiated(c->ssl->connection, &data, &len);
  #endif
  
              if (len == 2 && data[0] == 'h' && data[1] == '2') {
                  ngx_http_v2_init(c->read);
                  return;
              }
          }
          }
  #endif
  
          c->log->action = "waiting for request";
  
          c->read->handler = ngx_http_wait_request_handler;
          /* STUB: epoll edge */ c->write->handler = ngx_http_empty_handler;
  
          ngx_reusable_connection(c, 1);
  
          ngx_http_wait_request_handler(c->read);
  
          return;
      }
  
      if (c->read->timedout) {
          ngx_log_error(NGX_LOG_INFO, c->log, NGX_ETIMEDOUT, "client timed out");
      }
  
      ngx_http_close_connection(c);
  }
  
  
  #ifdef SSL_CTRL_SET_TLSEXT_HOSTNAME
  
  int
  ngx_http_ssl_servername(ngx_ssl_conn_t *ssl_conn, int *ad, void *arg)
  {
      ngx_int_t                  rc;
      ngx_str_t                  host;
      const char                *servername;
      ngx_connection_t          *c;
      ngx_http_connection_t     *hc;
      ngx_http_ssl_srv_conf_t   *sscf;
      ngx_http_core_loc_conf_t  *clcf;
      ngx_http_core_srv_conf_t  *cscf;
  
      c = ngx_ssl_get_connection(ssl_conn);
  
      if (c->ssl->handshaked) {
          *ad = SSL_AD_NO_RENEGOTIATION;
          return SSL_TLSEXT_ERR_ALERT_FATAL;
      }
  
      servername = SSL_get_servername(ssl_conn, TLSEXT_NAMETYPE_host_name);
  
      if (servername == NULL) {
          return SSL_TLSEXT_ERR_OK;
      }
  
      ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0,
                     "SSL server name: \"%s\"", servername);
  
      host.len = ngx_strlen(servername);
  
      if (host.len == 0) {
          return SSL_TLSEXT_ERR_OK;
      }
  
      host.data = (u_char *) servername;
  
      rc = ngx_http_validate_host(&host, c->pool, 1);
  
      if (rc == NGX_ERROR) {
          *ad = SSL_AD_INTERNAL_ERROR;
          return SSL_TLSEXT_ERR_ALERT_FATAL;
      }
  
      if (rc == NGX_DECLINED) {
          return SSL_TLSEXT_ERR_OK;
      }
  
      hc = c->data;
  
      rc = ngx_http_find_virtual_server(c, hc->addr_conf->virtual_names, &host,
                                        NULL, &cscf);
  
      if (rc == NGX_ERROR) {
          *ad = SSL_AD_INTERNAL_ERROR;
          return SSL_TLSEXT_ERR_ALERT_FATAL;
      }
  
      if (rc == NGX_DECLINED) {
          return SSL_TLSEXT_ERR_OK;
      }
  
      hc->ssl_servername = ngx_palloc(c->pool, sizeof(ngx_str_t));
      if (hc->ssl_servername == NULL) {
          *ad = SSL_AD_INTERNAL_ERROR;
          return SSL_TLSEXT_ERR_ALERT_FATAL;
      }
  
      *hc->ssl_servername = host;
  
      hc->conf_ctx = cscf->ctx;
  
      clcf = ngx_http_get_module_loc_conf(hc->conf_ctx, ngx_http_core_module);
  
      ngx_set_connection_log(c, clcf->error_log);
  
      sscf = ngx_http_get_module_srv_conf(hc->conf_ctx, ngx_http_ssl_module);
  
      c->ssl->buffer_size = sscf->buffer_size;
  
      if (sscf->ssl.ctx) {
          SSL_set_SSL_CTX(ssl_conn, sscf->ssl.ctx);
  
          /*
           * SSL_set_SSL_CTX() only changes certs as of 1.0.0d
           * adjust other things we care about
           */
  
          SSL_set_verify(ssl_conn, SSL_CTX_get_verify_mode(sscf->ssl.ctx),
                         SSL_CTX_get_verify_callback(sscf->ssl.ctx));
  
          SSL_set_verify_depth(ssl_conn, SSL_CTX_get_verify_depth(sscf->ssl.ctx));
  
  #if OPENSSL_VERSION_NUMBER >= 0x009080dfL
          /* only in 0.9.8m+ */
          SSL_clear_options(ssl_conn, SSL_get_options(ssl_conn) &
                                      ~SSL_CTX_get_options(sscf->ssl.ctx));
  #endif
  
          SSL_set_options(ssl_conn, SSL_CTX_get_options(sscf->ssl.ctx));
  
  #ifdef SSL_OP_NO_RENEGOTIATION
          SSL_set_options(ssl_conn, SSL_OP_NO_RENEGOTIATION);
  #endif
      }
  
      return SSL_TLSEXT_ERR_OK;
  }
  
  #endif
  
  
  #ifdef SSL_R_CERT_CB_ERROR
  
  int
  ngx_http_ssl_certificate(ngx_ssl_conn_t *ssl_conn, void *arg)
  {
      ngx_str_t                  cert, key;
      ngx_uint_t                 i, nelts;
      ngx_connection_t          *c;
      ngx_http_request_t        *r;
      ngx_http_ssl_srv_conf_t   *sscf;
      ngx_http_complex_value_t  *certs, *keys;
  
      c = ngx_ssl_get_connection(ssl_conn);
  
      if (c->ssl->handshaked) {
          return 0;
      }
  
      r = ngx_http_alloc_request(c);
      if (r == NULL) {
          return 0;
      }
  
      r->logged = 1;
  
      sscf = arg;
  
      nelts = sscf->certificate_values->nelts;
      certs = sscf->certificate_values->elts;
      keys = sscf->certificate_key_values->elts;
  
      for (i = 0; i < nelts; i++) {
  
          if (ngx_http_complex_value(r, &certs[i], &cert) != NGX_OK) {
              goto failed;
          }
  
          ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0,
                         "ssl cert: \"%s\"", cert.data);
  
          if (ngx_http_complex_value(r, &keys[i], &key) != NGX_OK) {
              goto failed;
          }
  
          ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0,
                         "ssl key: \"%s\"", key.data);
  
          if (ngx_ssl_connection_certificate(c, r->pool, &cert, &key,
                                             sscf->passwords)
              != NGX_OK)
          {
              goto failed;
          }
      }
  
      ngx_http_free_request(r, 0);
      c->destroyed = 0;
      return 1;
  
  failed:
  
      ngx_http_free_request(r, 0);
      c->destroyed = 0;
      return 0;
  }
  
  #endif
  
  #endif
  
  // 处理http数据包的请求报文
  static void
  ngx_http_process_request_line(ngx_event_t *rev)
  {
      ssize_t              n;
      ngx_int_t            rc, rv;
      ngx_str_t            host;
      ngx_connection_t    *c;
      ngx_http_request_t  *r;
  
      c = rev->data;
      r = c->data;
  
      ngx_log_debug0(NGX_LOG_DEBUG_HTTP, rev->log, 0,
                     "http process request line");
      // 超时了，关闭请求
      if (rev->timedout) {
          ngx_log_error(NGX_LOG_INFO, c->log, NGX_ETIMEDOUT, "client timed out");
          c->timedout = 1;
          ngx_http_close_request(r, NGX_HTTP_REQUEST_TIME_OUT);
          return;
      }
  
      rc = NGX_AGAIN;
  
      for ( ;; ) {
  
          if (rc == NGX_AGAIN) {
              n = ngx_http_read_request_header(r);
  
              if (n == NGX_AGAIN || n == NGX_ERROR) {
                  break;
              }
          }
          // 解析http请求行，r->header_in的内容由ngx_http_read_request_header设置
          rc = ngx_http_parse_request_line(r, r->header_in);
          // 请求行解析完
          if (rc == NGX_OK) {
  
              /* the request line has been parsed successfully */
  
              r->request_line.len = r->request_end - r->request_start;
              r->request_line.data = r->request_start;
              r->request_length = r->header_in->pos - r->request_start;
  
              ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0,
                             "http request line: \"%V\"", &r->request_line);
  
              r->method_name.len = r->method_end - r->request_start + 1;
              r->method_name.data = r->request_line.data;
  
              if (r->http_protocol.data) {
                  r->http_protocol.len = r->request_end - r->http_protocol.data;
              }
              // 解析请求行里的url
              if (ngx_http_process_request_uri(r) != NGX_OK) {
                  break;
              }
  
              if (r->schema_end) {
                  r->schema.len = r->schema_end - r->schema_start;
                  r->schema.data = r->schema_start;
              }
  
              if (r->host_end) {
  
                  host.len = r->host_end - r->host_start;
                  host.data = r->host_start;
  
                  rc = ngx_http_validate_host(&host, r->pool, 0);
  
                  if (rc == NGX_DECLINED) {
                      ngx_log_error(NGX_LOG_INFO, c->log, 0,
                                    "client sent invalid host in request line");
                      ngx_http_finalize_request(r, NGX_HTTP_BAD_REQUEST);
                      break;
                  }
  
                  if (rc == NGX_ERROR) {
                      ngx_http_close_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
                      break;
                  }
  
                  if (ngx_http_set_virtual_server(r, &host) == NGX_ERROR) {
                      break;
                  }
  
                  r->headers_in.server = host;
              }
  
              if (r->http_version < NGX_HTTP_VERSION_10) {
  
                  if (r->headers_in.server.len == 0
                      && ngx_http_set_virtual_server(r, &r->headers_in.server)
                         == NGX_ERROR)
                  {
                      break;
                  }
  
                  ngx_http_process_request(r);
                  break;
              }
  
  
              if (ngx_list_init(&r->headers_in.headers, r->pool, 20,
                                sizeof(ngx_table_elt_t))
                  != NGX_OK)
              {
                  ngx_http_close_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
                  break;
              }
  
              c->log->action = "reading client request headers";
              // 开始处理http头
              rev->handler = ngx_http_process_request_headers;
              ngx_http_process_request_headers(rev);
  
              break;
          }
          // NGX_AGAIN说明还没解析完，非NGX_AGAIN说明解析出错
          if (rc != NGX_AGAIN) {
  
              /* there was error while a request line parsing */
  
              ngx_log_error(NGX_LOG_INFO, c->log, 0,
                            ngx_http_client_errors[rc - NGX_HTTP_CLIENT_ERROR]);
  
              if (rc == NGX_HTTP_PARSE_INVALID_VERSION) {
                  ngx_http_finalize_request(r, NGX_HTTP_VERSION_NOT_SUPPORTED);
  
              } else {
                  ngx_http_finalize_request(r, NGX_HTTP_BAD_REQUEST);
              }
  
              break;
          }
  
          /* NGX_AGAIN: a request line parsing is still incomplete */
          // buf不够了，分配更大的
          if (r->header_in->pos == r->header_in->end) {
  
              rv = ngx_http_alloc_large_header_buffer(r, 1);
  
              if (rv == NGX_ERROR) {
                  ngx_http_close_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
                  break;
              }
  
              if (rv == NGX_DECLINED) {
                  r->request_line.len = r->header_in->end - r->request_start;
                  r->request_line.data = r->request_start;
  
                  ngx_log_error(NGX_LOG_INFO, c->log, 0,
                                "client sent too long URI");
                  ngx_http_finalize_request(r, NGX_HTTP_REQUEST_URI_TOO_LARGE);
                  break;
              }
          }
      }
  
      ngx_http_run_posted_requests(c);
  }
  
  
  ngx_int_t
  ngx_http_process_request_uri(ngx_http_request_t *r)
  {
      ngx_http_core_srv_conf_t  *cscf;
  
      if (r->args_start) {
          r->uri.len = r->args_start - 1 - r->uri_start;
      } else {
          r->uri.len = r->uri_end - r->uri_start;
      }
  
      if (r->complex_uri || r->quoted_uri) {
  
          r->uri.data = ngx_pnalloc(r->pool, r->uri.len + 1);
          if (r->uri.data == NULL) {
              ngx_http_close_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
              return NGX_ERROR;
          }
  
          cscf = ngx_http_get_module_srv_conf(r, ngx_http_core_module);
  
          if (ngx_http_parse_complex_uri(r, cscf->merge_slashes) != NGX_OK) {
              r->uri.len = 0;
  
              ngx_log_error(NGX_LOG_INFO, r->connection->log, 0,
                            "client sent invalid request");
              ngx_http_finalize_request(r, NGX_HTTP_BAD_REQUEST);
              return NGX_ERROR;
          }
  
      } else {
          r->uri.data = r->uri_start;
      }
  
      r->unparsed_uri.len = r->uri_end - r->uri_start;
      r->unparsed_uri.data = r->uri_start;
  
      r->valid_unparsed_uri = r->space_in_uri ? 0 : 1;
  
      if (r->uri_ext) {
          if (r->args_start) {
              r->exten.len = r->args_start - 1 - r->uri_ext;
          } else {
              r->exten.len = r->uri_end - r->uri_ext;
          }
  
          r->exten.data = r->uri_ext;
      }
  
      if (r->args_start && r->uri_end > r->args_start) {
          r->args.len = r->uri_end - r->args_start;
          r->args.data = r->args_start;
      }
  
  #if (NGX_WIN32)
      {
      u_char  *p, *last;
  
      p = r->uri.data;
      last = r->uri.data + r->uri.len;
  
      while (p < last) {
  
          if (*p++ == ':') {
  
              /*
               * this check covers "::$data", "::$index_allocation" and
               * ":$i30:$index_allocation"
               */
  
              if (p < last && *p == '$') {
                  ngx_log_error(NGX_LOG_INFO, r->connection->log, 0,
                                "client sent unsafe win32 URI");
                  ngx_http_finalize_request(r, NGX_HTTP_BAD_REQUEST);
                  return NGX_ERROR;
              }
          }
      }
  
      p = r->uri.data + r->uri.len - 1;
  
      while (p > r->uri.data) {
  
          if (*p == ' ') {
              p--;
              continue;
          }
  
          if (*p == '.') {
              p--;
              continue;
          }
  
          break;
      }
  
      if (p != r->uri.data + r->uri.len - 1) {
          r->uri.len = p + 1 - r->uri.data;
          ngx_http_set_exten(r);
      }
  
      }
  #endif
  
      ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                     "http uri: \"%V\"", &r->uri);
  
      ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                     "http args: \"%V\"", &r->args);
  
      ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                     "http exten: \"%V\"", &r->exten);
  
      return NGX_OK;
  }
  
  
  static void
  ngx_http_process_request_headers(ngx_event_t *rev)
  {
      u_char                     *p;
      size_t                      len;
      ssize_t                     n;
      ngx_int_t                   rc, rv;
      ngx_table_elt_t            *h;
      ngx_connection_t           *c;
      ngx_http_header_t          *hh;
      ngx_http_request_t         *r;
      ngx_http_core_srv_conf_t   *cscf;
      ngx_http_core_main_conf_t  *cmcf;
  
      c = rev->data;
      r = c->data;
  
      ngx_log_debug0(NGX_LOG_DEBUG_HTTP, rev->log, 0,
                     "http process request header line");
      // 读取http头超时
      if (rev->timedout) {
          ngx_log_error(NGX_LOG_INFO, c->log, NGX_ETIMEDOUT, "client timed out");
          c->timedout = 1;
          ngx_http_close_request(r, NGX_HTTP_REQUEST_TIME_OUT);
          return;
      }
  
      cmcf = ngx_http_get_module_main_conf(r, ngx_http_core_module);
  
      rc = NGX_AGAIN;
  
      for ( ;; ) {
  
          if (rc == NGX_AGAIN) {
              // buf不够了，分配更大的
              if (r->header_in->pos == r->header_in->end) {
  
                  rv = ngx_http_alloc_large_header_buffer(r, 0);
  
                  if (rv == NGX_ERROR) {
                      ngx_http_close_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
                      break;
                  }
  
                  if (rv == NGX_DECLINED) {
                      p = r->header_name_start;
  
                      r->lingering_close = 1;
  
                      if (p == NULL) {
                          ngx_log_error(NGX_LOG_INFO, c->log, 0,
                                        "client sent too large request");
                          ngx_http_finalize_request(r,
                                              NGX_HTTP_REQUEST_HEADER_TOO_LARGE);
                          break;
                      }
  
                      len = r->header_in->end - p;
  
                      if (len > NGX_MAX_ERROR_STR - 300) {
                          len = NGX_MAX_ERROR_STR - 300;
                      }
  
                      ngx_log_error(NGX_LOG_INFO, c->log, 0,
                                  "client sent too long header line: \"%*s...\"",
                                  len, r->header_name_start);
  
                      ngx_http_finalize_request(r,
                                              NGX_HTTP_REQUEST_HEADER_TOO_LARGE);
                      break;
                  }
              }
              // 读取请求头
              n = ngx_http_read_request_header(r);
  
              if (n == NGX_AGAIN || n == NGX_ERROR) {
                  break;
              }
          }
  
          /* the host header could change the server configuration context */
          cscf = ngx_http_get_module_srv_conf(r, ngx_http_core_module);
          // 解析http请求头
          rc = ngx_http_parse_header_line(r, r->header_in,
                                          cscf->underscores_in_headers);
          // 解析单个http头完成
          if (rc == NGX_OK) {
  
              r->request_length += r->header_in->pos - r->header_name_start;
  
              if (r->invalid_header && cscf->ignore_invalid_headers) {
  
                  /* there was error while a header line parsing */
  
                  ngx_log_error(NGX_LOG_INFO, c->log, 0,
                                "client sent invalid header line: \"%*s\"",
                                r->header_end - r->header_name_start,
                                r->header_name_start);
                  continue;
              }
  
              /* a header line has been parsed successfully */
              // 插入header数组
              h = ngx_list_push(&r->headers_in.headers);
              if (h == NULL) {
                  ngx_http_close_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
                  break;
              }
  
              h->hash = r->header_hash;
  
              h->key.len = r->header_name_end - r->header_name_start;
              h->key.data = r->header_name_start;
              h->key.data[h->key.len] = '\0';
  
              h->value.len = r->header_end - r->header_start;
              h->value.data = r->header_start;
              h->value.data[h->value.len] = '\0';
  
              h->lowcase_key = ngx_pnalloc(r->pool, h->key.len);
              if (h->lowcase_key == NULL) {
                  ngx_http_close_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
                  break;
              }
  
              if (h->key.len == r->lowcase_index) {
                  ngx_memcpy(h->lowcase_key, r->lowcase_header, h->key.len);
  
              } else {
                  ngx_strlow(h->lowcase_key, h->key.data, h->key.len);
              }
  
              hh = ngx_hash_find(&cmcf->headers_in_hash, h->hash,
                                 h->lowcase_key, h->key.len);
  
              if (hh && hh->handler(r, h, hh->offset) != NGX_OK) {
                  break;
              }
  
              ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                             "http header: \"%V: %V\"",
                             &h->key, &h->value);
  
              continue;
          }
          // 解析全部http头完成
          if (rc == NGX_HTTP_PARSE_HEADER_DONE) {
  
              /* a whole header has been parsed successfully */
  
              ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                             "http header done");
  
              r->request_length += r->header_in->pos - r->header_name_start;
  
              r->http_state = NGX_HTTP_PROCESS_REQUEST_STATE;
              // 校验头部
              rc = ngx_http_process_request_header(r);
  
              if (rc != NGX_OK) {
                  break;
              }
              // 进入http 11个请求阶段
              ngx_http_process_request(r);
  
              break;
          }
          // 一个http头还没解析完
          if (rc == NGX_AGAIN) {
  
              /* a header line parsing is still not complete */
  
              continue;
          }
  
          /* rc == NGX_HTTP_PARSE_INVALID_HEADER */
  
          ngx_log_error(NGX_LOG_INFO, c->log, 0,
                        "client sent invalid header line");
          // 解析出错
          ngx_http_finalize_request(r, NGX_HTTP_BAD_REQUEST);
          break;
      }
  
      ngx_http_run_posted_requests(c);
  }
  
  // 读取http头部
  static ssize_t
  ngx_http_read_request_header(ngx_http_request_t *r)
  {
      ssize_t                    n;
      ngx_event_t               *rev;
      ngx_connection_t          *c;
      ngx_http_core_srv_conf_t  *cscf;
  
      c = r->connection;
      rev = c->read;
      // 当前读取到的数据大小
      n = r->header_in->last - r->header_in->pos;
      // 有的话就返回
      if (n > 0) {
          return n;
      }
      // 可读则读取到请求结构体的header_in中，否则返回NGX_AGAIN
      if (rev->ready) {
          n = c->recv(c, r->header_in->last,
                      r->header_in->end - r->header_in->last);
      } else {
          n = NGX_AGAIN;
      }
      // 没有数据可读
      if (n == NGX_AGAIN) {
          // 还没有设置定时器（还没有插入定时器红黑树）
          if (!rev->timer_set) {
              cscf = ngx_http_get_module_srv_conf(r, ngx_http_core_module);
              // 根据nginx配置设置读取头部的超时时间
              ngx_add_timer(rev, cscf->client_header_timeout);
          }
          // 注册读事件
          if (ngx_handle_read_event(rev, 0) != NGX_OK) {
              ngx_http_close_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
              return NGX_ERROR;
          }
  
          return NGX_AGAIN;
      }
  
      if (n == 0) {
          ngx_log_error(NGX_LOG_INFO, c->log, 0,
                        "client prematurely closed connection");
      }
      // 读取出错，结束请求
      if (n == 0 || n == NGX_ERROR) {
          c->error = 1;
          c->log->action = "reading client request headers";
  
          ngx_http_finalize_request(r, NGX_HTTP_BAD_REQUEST);
          return NGX_ERROR;
      }
      // 读取成功，更新last指针
      r->header_in->last += n;
  
      return n;
  }
  
  
  static ngx_int_t
  ngx_http_alloc_large_header_buffer(ngx_http_request_t *r,
      ngx_uint_t request_line)
  {
      u_char                    *old, *new;
      ngx_buf_t                 *b;
      ngx_chain_t               *cl;
      ngx_http_connection_t     *hc;
      ngx_http_core_srv_conf_t  *cscf;
  
      ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                     "http alloc large header buffer");
  
      if (request_line && r->state == 0) {
  
          /* the client fills up the buffer with "\r\n" */
  
          r->header_in->pos = r->header_in->start;
          r->header_in->last = r->header_in->start;
  
          return NGX_OK;
      }
  
      old = request_line ? r->request_start : r->header_name_start;
  
      cscf = ngx_http_get_module_srv_conf(r, ngx_http_core_module);
  
      if (r->state != 0
          && (size_t) (r->header_in->pos - old)
                                       >= cscf->large_client_header_buffers.size)
      {
          return NGX_DECLINED;
      }
  
      hc = r->http_connection;
  
      if (hc->free) {
          cl = hc->free;
          hc->free = cl->next;
  
          b = cl->buf;
  
          ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                         "http large header free: %p %uz",
                         b->pos, b->end - b->last);
  
      } else if (hc->nbusy < cscf->large_client_header_buffers.num) {
  
          b = ngx_create_temp_buf(r->connection->pool,
                                  cscf->large_client_header_buffers.size);
          if (b == NULL) {
              return NGX_ERROR;
          }
  
          cl = ngx_alloc_chain_link(r->connection->pool);
          if (cl == NULL) {
              return NGX_ERROR;
          }
  
          cl->buf = b;
  
          ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                         "http large header alloc: %p %uz",
                         b->pos, b->end - b->last);
  
      } else {
          return NGX_DECLINED;
      }
  
      cl->next = hc->busy;
      hc->busy = cl;
      hc->nbusy++;
  
      if (r->state == 0) {
          /*
           * r->state == 0 means that a header line was parsed successfully
           * and we do not need to copy incomplete header line and
           * to relocate the parser header pointers
           */
  
          r->header_in = b;
  
          return NGX_OK;
      }
  
      ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                     "http large header copy: %uz", r->header_in->pos - old);
  
      new = b->start;
  
      ngx_memcpy(new, old, r->header_in->pos - old);
  
      b->pos = new + (r->header_in->pos - old);
      b->last = new + (r->header_in->pos - old);
  
      if (request_line) {
          r->request_start = new;
  
          if (r->request_end) {
              r->request_end = new + (r->request_end - old);
          }
  
          r->method_end = new + (r->method_end - old);
  
          r->uri_start = new + (r->uri_start - old);
          r->uri_end = new + (r->uri_end - old);
  
          if (r->schema_start) {
              r->schema_start = new + (r->schema_start - old);
              r->schema_end = new + (r->schema_end - old);
          }
  
          if (r->host_start) {
              r->host_start = new + (r->host_start - old);
              if (r->host_end) {
                  r->host_end = new + (r->host_end - old);
              }
          }
  
          if (r->port_start) {
              r->port_start = new + (r->port_start - old);
              r->port_end = new + (r->port_end - old);
          }
  
          if (r->uri_ext) {
              r->uri_ext = new + (r->uri_ext - old);
          }
  
          if (r->args_start) {
              r->args_start = new + (r->args_start - old);
          }
  
          if (r->http_protocol.data) {
              r->http_protocol.data = new + (r->http_protocol.data - old);
          }
  
      } else {
          r->header_name_start = new;
          r->header_name_end = new + (r->header_name_end - old);
          r->header_start = new + (r->header_start - old);
          r->header_end = new + (r->header_end - old);
      }
  
      r->header_in = b;
  
      return NGX_OK;
  }
  
  
  static ngx_int_t
  ngx_http_process_header_line(ngx_http_request_t *r, ngx_table_elt_t *h,
      ngx_uint_t offset)
  {
      ngx_table_elt_t  **ph;
  
      ph = (ngx_table_elt_t **) ((char *) &r->headers_in + offset);
  
      if (*ph == NULL) {
          *ph = h;
      }
  
      return NGX_OK;
  }
  
  
  static ngx_int_t
  ngx_http_process_unique_header_line(ngx_http_request_t *r, ngx_table_elt_t *h,
      ngx_uint_t offset)
  {
      ngx_table_elt_t  **ph;
  
      ph = (ngx_table_elt_t **) ((char *) &r->headers_in + offset);
  
      if (*ph == NULL) {
          *ph = h;
          return NGX_OK;
      }
  
      ngx_log_error(NGX_LOG_INFO, r->connection->log, 0,
                    "client sent duplicate header line: \"%V: %V\", "
                    "previous value: \"%V: %V\"",
                    &h->key, &h->value, &(*ph)->key, &(*ph)->value);
  
      ngx_http_finalize_request(r, NGX_HTTP_BAD_REQUEST);
  
      return NGX_ERROR;
  }
  
  
  static ngx_int_t
  ngx_http_process_host(ngx_http_request_t *r, ngx_table_elt_t *h,
      ngx_uint_t offset)
  {
      ngx_int_t  rc;
      ngx_str_t  host;
  
      if (r->headers_in.host) {
          ngx_log_error(NGX_LOG_INFO, r->connection->log, 0,
                        "client sent duplicate host header: \"%V: %V\", "
                        "previous value: \"%V: %V\"",
                        &h->key, &h->value, &r->headers_in.host->key,
                        &r->headers_in.host->value);
          ngx_http_finalize_request(r, NGX_HTTP_BAD_REQUEST);
          return NGX_ERROR;
      }
  
      r->headers_in.host = h;
  
      host = h->value;
  
      rc = ngx_http_validate_host(&host, r->pool, 0);
  
      if (rc == NGX_DECLINED) {
          ngx_log_error(NGX_LOG_INFO, r->connection->log, 0,
                        "client sent invalid host header");
          ngx_http_finalize_request(r, NGX_HTTP_BAD_REQUEST);
          return NGX_ERROR;
      }
  
      if (rc == NGX_ERROR) {
          ngx_http_close_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
          return NGX_ERROR;
      }
  
      if (r->headers_in.server.len) {
          return NGX_OK;
      }
  
      if (ngx_http_set_virtual_server(r, &host) == NGX_ERROR) {
          return NGX_ERROR;
      }
  
      r->headers_in.server = host;
  
      return NGX_OK;
  }
  
  
  static ngx_int_t
  ngx_http_process_connection(ngx_http_request_t *r, ngx_table_elt_t *h,
      ngx_uint_t offset)
  {
      if (ngx_strcasestrn(h->value.data, "close", 5 - 1)) {
          r->headers_in.connection_type = NGX_HTTP_CONNECTION_CLOSE;
  
      } else if (ngx_strcasestrn(h->value.data, "keep-alive", 10 - 1)) {
          r->headers_in.connection_type = NGX_HTTP_CONNECTION_KEEP_ALIVE;
      }
  
      return NGX_OK;
  }
  
  
  static ngx_int_t
  ngx_http_process_user_agent(ngx_http_request_t *r, ngx_table_elt_t *h,
      ngx_uint_t offset)
  {
      u_char  *user_agent, *msie;
  
      if (r->headers_in.user_agent) {
          return NGX_OK;
      }
  
      r->headers_in.user_agent = h;
  
      /* check some widespread browsers while the header is in CPU cache */
  
      user_agent = h->value.data;
  
      msie = ngx_strstrn(user_agent, "MSIE ", 5 - 1);
  
      if (msie && msie + 7 < user_agent + h->value.len) {
  
          r->headers_in.msie = 1;
  
          if (msie[6] == '.') {
  
              switch (msie[5]) {
              case '4':
              case '5':
                  r->headers_in.msie6 = 1;
                  break;
              case '6':
                  if (ngx_strstrn(msie + 8, "SV1", 3 - 1) == NULL) {
                      r->headers_in.msie6 = 1;
                  }
                  break;
              }
          }
  
  #if 0
          /* MSIE ignores the SSL "close notify" alert */
          if (c->ssl) {
              c->ssl->no_send_shutdown = 1;
          }
  #endif
      }
  
      if (ngx_strstrn(user_agent, "Opera", 5 - 1)) {
          r->headers_in.opera = 1;
          r->headers_in.msie = 0;
          r->headers_in.msie6 = 0;
      }
  
      if (!r->headers_in.msie && !r->headers_in.opera) {
  
          if (ngx_strstrn(user_agent, "Gecko/", 6 - 1)) {
              r->headers_in.gecko = 1;
  
          } else if (ngx_strstrn(user_agent, "Chrome/", 7 - 1)) {
              r->headers_in.chrome = 1;
  
          } else if (ngx_strstrn(user_agent, "Safari/", 7 - 1)
                     && ngx_strstrn(user_agent, "Mac OS X", 8 - 1))
          {
              r->headers_in.safari = 1;
  
          } else if (ngx_strstrn(user_agent, "Konqueror", 9 - 1)) {
              r->headers_in.konqueror = 1;
          }
      }
  
      return NGX_OK;
  }
  
  
  static ngx_int_t
  ngx_http_process_multi_header_lines(ngx_http_request_t *r, ngx_table_elt_t *h,
      ngx_uint_t offset)
  {
      ngx_array_t       *headers;
      ngx_table_elt_t  **ph;
  
      headers = (ngx_array_t *) ((char *) &r->headers_in + offset);
  
      if (headers->elts == NULL) {
          if (ngx_array_init(headers, r->pool, 1, sizeof(ngx_table_elt_t *))
              != NGX_OK)
          {
              ngx_http_close_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
              return NGX_ERROR;
          }
      }
  
      ph = ngx_array_push(headers);
      if (ph == NULL) {
          ngx_http_close_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
          return NGX_ERROR;
      }
  
      *ph = h;
      return NGX_OK;
  }
  
  
  ngx_int_t
  ngx_http_process_request_header(ngx_http_request_t *r)
  {
      if (r->headers_in.server.len == 0
          && ngx_http_set_virtual_server(r, &r->headers_in.server)
             == NGX_ERROR)
      {
          return NGX_ERROR;
      }
  
      if (r->headers_in.host == NULL && r->http_version > NGX_HTTP_VERSION_10) {
          ngx_log_error(NGX_LOG_INFO, r->connection->log, 0,
                     "client sent HTTP/1.1 request without \"Host\" header");
          ngx_http_finalize_request(r, NGX_HTTP_BAD_REQUEST);
          return NGX_ERROR;
      }
  
      if (r->headers_in.content_length) {
          r->headers_in.content_length_n =
                              ngx_atoof(r->headers_in.content_length->value.data,
                                        r->headers_in.content_length->value.len);
  
          if (r->headers_in.content_length_n == NGX_ERROR) {
              ngx_log_error(NGX_LOG_INFO, r->connection->log, 0,
                            "client sent invalid \"Content-Length\" header");
              ngx_http_finalize_request(r, NGX_HTTP_BAD_REQUEST);
              return NGX_ERROR;
          }
      }
  
      if (r->method == NGX_HTTP_TRACE) {
          ngx_log_error(NGX_LOG_INFO, r->connection->log, 0,
                        "client sent TRACE method");
          ngx_http_finalize_request(r, NGX_HTTP_NOT_ALLOWED);
          return NGX_ERROR;
      }
  
      if (r->headers_in.transfer_encoding) {
          if (r->headers_in.transfer_encoding->value.len == 7
              && ngx_strncasecmp(r->headers_in.transfer_encoding->value.data,
                                 (u_char *) "chunked", 7) == 0)
          {
              r->headers_in.content_length = NULL;
              r->headers_in.content_length_n = -1;
              r->headers_in.chunked = 1;
  
          } else {
              ngx_log_error(NGX_LOG_INFO, r->connection->log, 0,
                            "client sent unknown \"Transfer-Encoding\": \"%V\"",
                            &r->headers_in.transfer_encoding->value);
              ngx_http_finalize_request(r, NGX_HTTP_NOT_IMPLEMENTED);
              return NGX_ERROR;
          }
      }
  
      if (r->headers_in.connection_type == NGX_HTTP_CONNECTION_KEEP_ALIVE) {
          if (r->headers_in.keep_alive) {
              r->headers_in.keep_alive_n =
                              ngx_atotm(r->headers_in.keep_alive->value.data,
                                        r->headers_in.keep_alive->value.len);
          }
      }
  
      return NGX_OK;
  }
  
  
  void
  ngx_http_process_request(ngx_http_request_t *r)
  {
      ngx_connection_t  *c;
  
      c = r->connection;
  
  #if (NGX_HTTP_SSL)
  
      if (r->http_connection->ssl) {
          long                      rc;
          X509                     *cert;
          ngx_http_ssl_srv_conf_t  *sscf;
  
          if (c->ssl == NULL) {
              ngx_log_error(NGX_LOG_INFO, c->log, 0,
                            "client sent plain HTTP request to HTTPS port");
              ngx_http_finalize_request(r, NGX_HTTP_TO_HTTPS);
              return;
          }
  
          sscf = ngx_http_get_module_srv_conf(r, ngx_http_ssl_module);
  
          if (sscf->verify) {
              rc = SSL_get_verify_result(c->ssl->connection);
  
              if (rc != X509_V_OK
                  && (sscf->verify != 3 || !ngx_ssl_verify_error_optional(rc)))
              {
                  ngx_log_error(NGX_LOG_INFO, c->log, 0,
                                "client SSL certificate verify error: (%l:%s)",
                                rc, X509_verify_cert_error_string(rc));
  
                  ngx_ssl_remove_cached_session(c->ssl->session_ctx,
                                         (SSL_get0_session(c->ssl->connection)));
  
                  ngx_http_finalize_request(r, NGX_HTTPS_CERT_ERROR);
                  return;
              }
  
              if (sscf->verify == 1) {
                  cert = SSL_get_peer_certificate(c->ssl->connection);
  
                  if (cert == NULL) {
                      ngx_log_error(NGX_LOG_INFO, c->log, 0,
                                    "client sent no required SSL certificate");
  
                      ngx_ssl_remove_cached_session(c->ssl->session_ctx,
                                         (SSL_get0_session(c->ssl->connection)));
  
                      ngx_http_finalize_request(r, NGX_HTTPS_NO_CERT);
                      return;
                  }
  
                  X509_free(cert);
              }
          }
      }
  
  #endif
  
      if (c->read->timer_set) {
          ngx_del_timer(c->read);
      }
  
  #if (NGX_STAT_STUB)
      (void) ngx_atomic_fetch_add(ngx_stat_reading, -1);
      r->stat_reading = 0;
      (void) ngx_atomic_fetch_add(ngx_stat_writing, 1);
      r->stat_writing = 1;
  #endif
  
      c->read->handler = ngx_http_request_handler;
      c->write->handler = ngx_http_request_handler;
      r->read_event_handler = ngx_http_block_reading;
  
      ngx_http_handler(r);
  }
  
  
  static ngx_int_t
  ngx_http_validate_host(ngx_str_t *host, ngx_pool_t *pool, ngx_uint_t alloc)
  {
      u_char  *h, ch;
      size_t   i, dot_pos, host_len;
  
      enum {
          sw_usual = 0,
          sw_literal,
          sw_rest
      } state;
  
      dot_pos = host->len;
      host_len = host->len;
  
      h = host->data;
  
      state = sw_usual;
  
      for (i = 0; i < host->len; i++) {
          ch = h[i];
  
          switch (ch) {
  
          case '.':
              if (dot_pos == i - 1) {
                  return NGX_DECLINED;
              }
              dot_pos = i;
              break;
  
          case ':':
              if (state == sw_usual) {
                  host_len = i;
                  state = sw_rest;
              }
              break;
  
          case '[':
              if (i == 0) {
                  state = sw_literal;
              }
              break;
  
          case ']':
              if (state == sw_literal) {
                  host_len = i + 1;
                  state = sw_rest;
              }
              break;
  
          case '\0':
              return NGX_DECLINED;
  
          default:
  
              if (ngx_path_separator(ch)) {
                  return NGX_DECLINED;
              }
  
              if (ch >= 'A' && ch <= 'Z') {
                  alloc = 1;
              }
  
              break;
          }
      }
  
      if (dot_pos == host_len - 1) {
          host_len--;
      }
  
      if (host_len == 0) {
          return NGX_DECLINED;
      }
  
      if (alloc) {
          host->data = ngx_pnalloc(pool, host_len);
          if (host->data == NULL) {
              return NGX_ERROR;
          }
  
          ngx_strlow(host->data, h, host_len);
      }
  
      host->len = host_len;
  
      return NGX_OK;
  }
  
  
  static ngx_int_t
  ngx_http_set_virtual_server(ngx_http_request_t *r, ngx_str_t *host)
  {
      ngx_int_t                  rc;
      ngx_http_connection_t     *hc;
      ngx_http_core_loc_conf_t  *clcf;
      ngx_http_core_srv_conf_t  *cscf;
  
  #if (NGX_SUPPRESS_WARN)
      cscf = NULL;
  #endif
  
      hc = r->http_connection;
  
  #if (NGX_HTTP_SSL && defined SSL_CTRL_SET_TLSEXT_HOSTNAME)
  
      if (hc->ssl_servername) {
          if (hc->ssl_servername->len == host->len
              && ngx_strncmp(hc->ssl_servername->data,
                             host->data, host->len) == 0)
          {
  #if (NGX_PCRE)
              if (hc->ssl_servername_regex
                  && ngx_http_regex_exec(r, hc->ssl_servername_regex,
                                            hc->ssl_servername) != NGX_OK)
              {
                  ngx_http_close_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
                  return NGX_ERROR;
              }
  #endif
              return NGX_OK;
          }
      }
  
  #endif
  
      rc = ngx_http_find_virtual_server(r->connection,
                                        hc->addr_conf->virtual_names,
                                        host, r, &cscf);
  
      if (rc == NGX_ERROR) {
          ngx_http_close_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
          return NGX_ERROR;
      }
  
  #if (NGX_HTTP_SSL && defined SSL_CTRL_SET_TLSEXT_HOSTNAME)
  
      if (hc->ssl_servername) {
          ngx_http_ssl_srv_conf_t  *sscf;
  
          if (rc == NGX_DECLINED) {
              cscf = hc->addr_conf->default_server;
              rc = NGX_OK;
          }
  
          sscf = ngx_http_get_module_srv_conf(cscf->ctx, ngx_http_ssl_module);
  
          if (sscf->verify) {
              ngx_log_error(NGX_LOG_INFO, r->connection->log, 0,
                            "client attempted to request the server name "
                            "different from the one that was negotiated");
              ngx_http_finalize_request(r, NGX_HTTP_MISDIRECTED_REQUEST);
              return NGX_ERROR;
          }
      }
  
  #endif
  
      if (rc == NGX_DECLINED) {
          return NGX_OK;
      }
  
      r->srv_conf = cscf->ctx->srv_conf;
      r->loc_conf = cscf->ctx->loc_conf;
  
      clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);
  
      ngx_set_connection_log(r->connection, clcf->error_log);
  
      return NGX_OK;
  }
  
  
  static ngx_int_t
  ngx_http_find_virtual_server(ngx_connection_t *c,
      ngx_http_virtual_names_t *virtual_names, ngx_str_t *host,
      ngx_http_request_t *r, ngx_http_core_srv_conf_t **cscfp)
  {
      ngx_http_core_srv_conf_t  *cscf;
  
      if (virtual_names == NULL) {
          return NGX_DECLINED;
      }
  
      cscf = ngx_hash_find_combined(&virtual_names->names,
                                    ngx_hash_key(host->data, host->len),
                                    host->data, host->len);
  
      if (cscf) {
          *cscfp = cscf;
          return NGX_OK;
      }
  
  #if (NGX_PCRE)
  
      if (host->len && virtual_names->nregex) {
          ngx_int_t                n;
          ngx_uint_t               i;
          ngx_http_server_name_t  *sn;
  
          sn = virtual_names->regex;
  
  #if (NGX_HTTP_SSL && defined SSL_CTRL_SET_TLSEXT_HOSTNAME)
  
          if (r == NULL) {
              ngx_http_connection_t  *hc;
  
              for (i = 0; i < virtual_names->nregex; i++) {
  
                  n = ngx_regex_exec(sn[i].regex->regex, host, NULL, 0);
  
                  if (n == NGX_REGEX_NO_MATCHED) {
                      continue;
                  }
  
                  if (n >= 0) {
                      hc = c->data;
                      hc->ssl_servername_regex = sn[i].regex;
  
                      *cscfp = sn[i].server;
                      return NGX_OK;
                  }
  
                  ngx_log_error(NGX_LOG_ALERT, c->log, 0,
                                ngx_regex_exec_n " failed: %i "
                                "on \"%V\" using \"%V\"",
                                n, host, &sn[i].regex->name);
  
                  return NGX_ERROR;
              }
  
              return NGX_DECLINED;
          }
  
  #endif /* NGX_HTTP_SSL && defined SSL_CTRL_SET_TLSEXT_HOSTNAME */
  
          for (i = 0; i < virtual_names->nregex; i++) {
  
              n = ngx_http_regex_exec(r, sn[i].regex, host);
  
              if (n == NGX_DECLINED) {
                  continue;
              }
  
              if (n == NGX_OK) {
                  *cscfp = sn[i].server;
                  return NGX_OK;
              }
  
              return NGX_ERROR;
          }
      }
  
  #endif /* NGX_PCRE */
  
      return NGX_DECLINED;
  }
  
  // 处理完http头后，执行该函数
  static void
  ngx_http_request_handler(ngx_event_t *ev)
  {
      ngx_connection_t    *c;
      ngx_http_request_t  *r;
  
      c = ev->data;
      r = c->data;
  
      ngx_http_set_log_request(c->log, r);
  
      ngx_log_debug2(NGX_LOG_DEBUG_HTTP, c->log, 0,
                     "http run request: \"%V?%V\"", &r->uri, &r->args);
  
      if (c->close) {
          r->main->count++;
          ngx_http_terminate_request(r, 0);
          ngx_http_run_posted_requests(c);
          return;
      }
  
      if (ev->delayed && ev->timedout) {
          ev->delayed = 0;
          ev->timedout = 0;
      }
      // 可读还是可写
      if (ev->write) {
          r->write_event_handler(r);
  
      } else {
          r->read_event_handler(r);
      }
  
      ngx_http_run_posted_requests(c);
  }
  
  
  void
  ngx_http_run_posted_requests(ngx_connection_t *c)
  {
      ngx_http_request_t         *r;
      ngx_http_posted_request_t  *pr;
  
      for ( ;; ) {
  
          if (c->destroyed) {
              return;
          }
  
          r = c->data;
          pr = r->main->posted_requests;
  
          if (pr == NULL) {
              return;
          }
  
          r->main->posted_requests = pr->next;
  
          r = pr->request;
  
          ngx_http_set_log_request(c->log, r);
  
          ngx_log_debug2(NGX_LOG_DEBUG_HTTP, c->log, 0,
                         "http posted request: \"%V?%V\"", &r->uri, &r->args);
  
          r->write_event_handler(r);
      }
  }
  
  
  ngx_int_t
  ngx_http_post_request(ngx_http_request_t *r, ngx_http_posted_request_t *pr)
  {
      ngx_http_posted_request_t  **p;
  
      if (pr == NULL) {
          pr = ngx_palloc(r->pool, sizeof(ngx_http_posted_request_t));
          if (pr == NULL) {
              return NGX_ERROR;
          }
      }
  
      pr->request = r;
      pr->next = NULL;
  
      for (p = &r->main->posted_requests; *p; p = &(*p)->next) { /* void */ }
  
      *p = pr;
  
      return NGX_OK;
  }
  
  
  void
  ngx_http_finalize_request(ngx_http_request_t *r, ngx_int_t rc)
  {
      ngx_connection_t          *c;
      ngx_http_request_t        *pr;
      ngx_http_core_loc_conf_t  *clcf;
  
      c = r->connection;
  
      ngx_log_debug5(NGX_LOG_DEBUG_HTTP, c->log, 0,
                     "http finalize request: %i, \"%V?%V\" a:%d, c:%d",
                     rc, &r->uri, &r->args, r == c->data, r->main->count);
  
      if (rc == NGX_DONE) {
          ngx_http_finalize_connection(r);
          return;
      }
  
      if (rc == NGX_OK && r->filter_finalize) {
          c->error = 1;
      }
  
      if (rc == NGX_DECLINED) {
          r->content_handler = NULL;
          r->write_event_handler = ngx_http_core_run_phases;
          ngx_http_core_run_phases(r);
          return;
      }
  
      if (r != r->main && r->post_subrequest) {
          rc = r->post_subrequest->handler(r, r->post_subrequest->data, rc);
      }
  
      if (rc == NGX_ERROR
          || rc == NGX_HTTP_REQUEST_TIME_OUT
          || rc == NGX_HTTP_CLIENT_CLOSED_REQUEST
          || c->error)
      {
          if (ngx_http_post_action(r) == NGX_OK) {
              return;
          }
  
          ngx_http_terminate_request(r, rc);
          return;
      }
  
      if (rc >= NGX_HTTP_SPECIAL_RESPONSE
          || rc == NGX_HTTP_CREATED
          || rc == NGX_HTTP_NO_CONTENT)
      {
          if (rc == NGX_HTTP_CLOSE) {
              c->timedout = 1;
              ngx_http_terminate_request(r, rc);
              return;
          }
  
          if (r == r->main) {
              if (c->read->timer_set) {
                  ngx_del_timer(c->read);
              }
  
              if (c->write->timer_set) {
                  ngx_del_timer(c->write);
              }
          }
  
          c->read->handler = ngx_http_request_handler;
          c->write->handler = ngx_http_request_handler;
  
          ngx_http_finalize_request(r, ngx_http_special_response_handler(r, rc));
          return;
      }
  
      if (r != r->main) {
  
          if (r->buffered || r->postponed) {
  
              if (ngx_http_set_write_handler(r) != NGX_OK) {
                  ngx_http_terminate_request(r, 0);
              }
  
              return;
          }
  
          pr = r->parent;
  
          if (r == c->data || r->background) {
  
              if (!r->logged) {
  
                  clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);
  
                  if (clcf->log_subrequest) {
                      ngx_http_log_request(r);
                  }
  
                  r->logged = 1;
  
              } else {
                  ngx_log_error(NGX_LOG_ALERT, c->log, 0,
                                "subrequest: \"%V?%V\" logged again",
                                &r->uri, &r->args);
              }
  
              r->done = 1;
  
              if (r->background) {
                  ngx_http_finalize_connection(r);
                  return;
              }
  
              r->main->count--;
  
              if (pr->postponed && pr->postponed->request == r) {
                  pr->postponed = pr->postponed->next;
              }
  
              c->data = pr;
  
          } else {
  
              ngx_log_debug2(NGX_LOG_DEBUG_HTTP, c->log, 0,
                             "http finalize non-active request: \"%V?%V\"",
                             &r->uri, &r->args);
  
              r->write_event_handler = ngx_http_request_finalizer;
  
              if (r->waited) {
                  r->done = 1;
              }
          }
  
          if (ngx_http_post_request(pr, NULL) != NGX_OK) {
              r->main->count++;
              ngx_http_terminate_request(r, 0);
              return;
          }
  
          ngx_log_debug2(NGX_LOG_DEBUG_HTTP, c->log, 0,
                         "http wake parent request: \"%V?%V\"",
                         &pr->uri, &pr->args);
  
          return;
      }
  
      if (r->buffered || c->buffered || r->postponed) {
  
          if (ngx_http_set_write_handler(r) != NGX_OK) {
              ngx_http_terminate_request(r, 0);
          }
  
          return;
      }
  
      if (r != c->data) {
          ngx_log_error(NGX_LOG_ALERT, c->log, 0,
                        "http finalize non-active request: \"%V?%V\"",
                        &r->uri, &r->args);
          return;
      }
  
      r->done = 1;
  
      r->read_event_handler = ngx_http_block_reading;
      r->write_event_handler = ngx_http_request_empty_handler;
  
      if (!r->post_action) {
          r->request_complete = 1;
      }
  
      if (ngx_http_post_action(r) == NGX_OK) {
          return;
      }
  
      if (c->read->timer_set) {
          ngx_del_timer(c->read);
      }
  
      if (c->write->timer_set) {
          c->write->delayed = 0;
          ngx_del_timer(c->write);
      }
  
      if (c->read->eof) {
          ngx_http_close_request(r, 0);
          return;
      }
  
      ngx_http_finalize_connection(r);
  }
  
  
  static void
  ngx_http_terminate_request(ngx_http_request_t *r, ngx_int_t rc)
  {
      ngx_http_cleanup_t    *cln;
      ngx_http_request_t    *mr;
      ngx_http_ephemeral_t  *e;
  
      mr = r->main;
  
      ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                     "http terminate request count:%d", mr->count);
  
      if (rc > 0 && (mr->headers_out.status == 0 || mr->connection->sent == 0)) {
          mr->headers_out.status = rc;
      }
  
      cln = mr->cleanup;
      mr->cleanup = NULL;
  
      while (cln) {
          if (cln->handler) {
              cln->handler(cln->data);
          }
  
          cln = cln->next;
      }
  
      ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                     "http terminate cleanup count:%d blk:%d",
                     mr->count, mr->blocked);
  
      if (mr->write_event_handler) {
  
          if (mr->blocked) {
              r->connection->error = 1;
              r->write_event_handler = ngx_http_request_finalizer;
              return;
          }
  
          e = ngx_http_ephemeral(mr);
          mr->posted_requests = NULL;
          mr->write_event_handler = ngx_http_terminate_handler;
          (void) ngx_http_post_request(mr, &e->terminal_posted_request);
          return;
      }
  
      ngx_http_close_request(mr, rc);
  }
  
  
  static void
  ngx_http_terminate_handler(ngx_http_request_t *r)
  {
      ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                     "http terminate handler count:%d", r->count);
  
      r->count = 1;
  
      ngx_http_close_request(r, 0);
  }
  
  
  static void
  ngx_http_finalize_connection(ngx_http_request_t *r)
  {
      ngx_http_core_loc_conf_t  *clcf;
  
  #if (NGX_HTTP_V2)
      if (r->stream) {
          ngx_http_close_request(r, 0);
          return;
      }
  #endif
  
      clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);
  
      if (r->main->count != 1) {
  
          if (r->discard_body) {
              r->read_event_handler = ngx_http_discarded_request_body_handler;
              ngx_add_timer(r->connection->read, clcf->lingering_timeout);
  
              if (r->lingering_time == 0) {
                  r->lingering_time = ngx_time()
                                        + (time_t) (clcf->lingering_time / 1000);
              }
          }
  
          ngx_http_close_request(r, 0);
          return;
      }
  
      r = r->main;
  
      if (r->reading_body) {
          r->keepalive = 0;
          r->lingering_close = 1;
      }
  
      if (!ngx_terminate
           && !ngx_exiting
           && r->keepalive
           && clcf->keepalive_timeout > 0)
      {
          ngx_http_set_keepalive(r);
          return;
      }
  
      if (clcf->lingering_close == NGX_HTTP_LINGERING_ALWAYS
          || (clcf->lingering_close == NGX_HTTP_LINGERING_ON
              && (r->lingering_close
                  || r->header_in->pos < r->header_in->last
                  || r->connection->read->ready)))
      {
          ngx_http_set_lingering_close(r);
          return;
      }
  
      ngx_http_close_request(r, 0);
  }
  
  
  static ngx_int_t
  ngx_http_set_write_handler(ngx_http_request_t *r)
  {
      ngx_event_t               *wev;
      ngx_http_core_loc_conf_t  *clcf;
  
      r->http_state = NGX_HTTP_WRITING_REQUEST_STATE;
  
      r->read_event_handler = r->discard_body ?
                                  ngx_http_discarded_request_body_handler:
                                  ngx_http_test_reading;
      r->write_event_handler = ngx_http_writer;
  
      wev = r->connection->write;
  
      if (wev->ready && wev->delayed) {
          return NGX_OK;
      }
  
      clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);
      if (!wev->delayed) {
          ngx_add_timer(wev, clcf->send_timeout);
      }
  
      if (ngx_handle_write_event(wev, clcf->send_lowat) != NGX_OK) {
          ngx_http_close_request(r, 0);
          return NGX_ERROR;
      }
  
      return NGX_OK;
  }
  
  
  static void
  ngx_http_writer(ngx_http_request_t *r)
  {
      ngx_int_t                  rc;
      ngx_event_t               *wev;
      ngx_connection_t          *c;
      ngx_http_core_loc_conf_t  *clcf;
  
      c = r->connection;
      wev = c->write;
  
      ngx_log_debug2(NGX_LOG_DEBUG_HTTP, wev->log, 0,
                     "http writer handler: \"%V?%V\"", &r->uri, &r->args);
  
      clcf = ngx_http_get_module_loc_conf(r->main, ngx_http_core_module);
  
      if (wev->timedout) {
          ngx_log_error(NGX_LOG_INFO, c->log, NGX_ETIMEDOUT,
                        "client timed out");
          c->timedout = 1;
  
          ngx_http_finalize_request(r, NGX_HTTP_REQUEST_TIME_OUT);
          return;
      }
  
      if (wev->delayed || r->aio) {
          ngx_log_debug0(NGX_LOG_DEBUG_HTTP, wev->log, 0,
                         "http writer delayed");
  
          if (!wev->delayed) {
              ngx_add_timer(wev, clcf->send_timeout);
          }
  
          if (ngx_handle_write_event(wev, clcf->send_lowat) != NGX_OK) {
              ngx_http_close_request(r, 0);
          }
  
          return;
      }
  
      rc = ngx_http_output_filter(r, NULL);
  
      ngx_log_debug3(NGX_LOG_DEBUG_HTTP, c->log, 0,
                     "http writer output filter: %i, \"%V?%V\"",
                     rc, &r->uri, &r->args);
  
      if (rc == NGX_ERROR) {
          ngx_http_finalize_request(r, rc);
          return;
      }
  
      if (r->buffered || r->postponed || (r == r->main && c->buffered)) {
  
          if (!wev->delayed) {
              ngx_add_timer(wev, clcf->send_timeout);
          }
  
          if (ngx_handle_write_event(wev, clcf->send_lowat) != NGX_OK) {
              ngx_http_close_request(r, 0);
          }
  
          return;
      }
  
      ngx_log_debug2(NGX_LOG_DEBUG_HTTP, wev->log, 0,
                     "http writer done: \"%V?%V\"", &r->uri, &r->args);
  
      r->write_event_handler = ngx_http_request_empty_handler;
  
      ngx_http_finalize_request(r, rc);
  }
  
  
  static void
  ngx_http_request_finalizer(ngx_http_request_t *r)
  {
      ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                     "http finalizer done: \"%V?%V\"", &r->uri, &r->args);
  
      ngx_http_finalize_request(r, 0);
  }
  
  
  void
  ngx_http_block_reading(ngx_http_request_t *r)
  {
      ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                     "http reading blocked");
  
      /* aio does not call this handler */
  
      if ((ngx_event_flags & NGX_USE_LEVEL_EVENT)
          && r->connection->read->active)
      {
          if (ngx_del_event(r->connection->read, NGX_READ_EVENT, 0) != NGX_OK) {
              ngx_http_close_request(r, 0);
          }
      }
  }
  
  
  void
  ngx_http_test_reading(ngx_http_request_t *r)
  {
      int                n;
      char               buf[1];
      ngx_err_t          err;
      ngx_event_t       *rev;
      ngx_connection_t  *c;
  
      c = r->connection;
      rev = c->read;
  
      ngx_log_debug0(NGX_LOG_DEBUG_HTTP, c->log, 0, "http test reading");
  
  #if (NGX_HTTP_V2)
  
      if (r->stream) {
          if (c->error) {
              err = 0;
              goto closed;
          }
  
          return;
      }
  
  #endif
  
  #if (NGX_HAVE_KQUEUE)
  
      if (ngx_event_flags & NGX_USE_KQUEUE_EVENT) {
  
          if (!rev->pending_eof) {
              return;
          }
  
          rev->eof = 1;
          c->error = 1;
          err = rev->kq_errno;
  
          goto closed;
      }
  
  #endif
  
  #if (NGX_HAVE_EPOLLRDHUP)
  
      if ((ngx_event_flags & NGX_USE_EPOLL_EVENT) && ngx_use_epoll_rdhup) {
          socklen_t  len;
  
          if (!rev->pending_eof) {
              return;
          }
  
          rev->eof = 1;
          c->error = 1;
  
          err = 0;
          len = sizeof(ngx_err_t);
  
          /*
           * BSDs and Linux return 0 and set a pending error in err
           * Solaris returns -1 and sets errno
           */
  
          if (getsockopt(c->fd, SOL_SOCKET, SO_ERROR, (void *) &err, &len)
              == -1)
          {
              err = ngx_socket_errno;
          }
  
          goto closed;
      }
  
  #endif
  
      n = recv(c->fd, buf, 1, MSG_PEEK);
  
      if (n == 0) {
          rev->eof = 1;
          c->error = 1;
          err = 0;
  
          goto closed;
  
      } else if (n == -1) {
          err = ngx_socket_errno;
  
          if (err != NGX_EAGAIN) {
              rev->eof = 1;
              c->error = 1;
  
              goto closed;
          }
      }
  
      /* aio does not call this handler */
  
      if ((ngx_event_flags & NGX_USE_LEVEL_EVENT) && rev->active) {
  
          if (ngx_del_event(rev, NGX_READ_EVENT, 0) != NGX_OK) {
              ngx_http_close_request(r, 0);
          }
      }
  
      return;
  
  closed:
  
      if (err) {
          rev->error = 1;
      }
  
      ngx_log_error(NGX_LOG_INFO, c->log, err,
                    "client prematurely closed connection");
  
      ngx_http_finalize_request(r, NGX_HTTP_CLIENT_CLOSED_REQUEST);
  }
  
  
  static void
  ngx_http_set_keepalive(ngx_http_request_t *r)
  {
      int                        tcp_nodelay;
      ngx_buf_t                 *b, *f;
      ngx_chain_t               *cl, *ln;
      ngx_event_t               *rev, *wev;
      ngx_connection_t          *c;
      ngx_http_connection_t     *hc;
      ngx_http_core_loc_conf_t  *clcf;
  
      c = r->connection;
      rev = c->read;
  
      clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);
  
      ngx_log_debug0(NGX_LOG_DEBUG_HTTP, c->log, 0, "set http keepalive handler");
  
      if (r->discard_body) {
          r->write_event_handler = ngx_http_request_empty_handler;
          r->lingering_time = ngx_time() + (time_t) (clcf->lingering_time / 1000);
          ngx_add_timer(rev, clcf->lingering_timeout);
          return;
      }
  
      c->log->action = "closing request";
  
      hc = r->http_connection;
      b = r->header_in;
  
      if (b->pos < b->last) {
  
          /* the pipelined request */
  
          if (b != c->buffer) {
  
              /*
               * If the large header buffers were allocated while the previous
               * request processing then we do not use c->buffer for
               * the pipelined request (see ngx_http_create_request()).
               *
               * Now we would move the large header buffers to the free list.
               */
  
              for (cl = hc->busy; cl; /* void */) {
                  ln = cl;
                  cl = cl->next;
  
                  if (ln->buf == b) {
                      ngx_free_chain(c->pool, ln);
                      continue;
                  }
  
                  f = ln->buf;
                  f->pos = f->start;
                  f->last = f->start;
  
                  ln->next = hc->free;
                  hc->free = ln;
              }
  
              cl = ngx_alloc_chain_link(c->pool);
              if (cl == NULL) {
                  ngx_http_close_request(r, 0);
                  return;
              }
  
              cl->buf = b;
              cl->next = NULL;
  
              hc->busy = cl;
              hc->nbusy = 1;
          }
      }
  
      /* guard against recursive call from ngx_http_finalize_connection() */
      r->keepalive = 0;
  
      ngx_http_free_request(r, 0);
  
      c->data = hc;
  
      if (ngx_handle_read_event(rev, 0) != NGX_OK) {
          ngx_http_close_connection(c);
          return;
      }
  
      wev = c->write;
      wev->handler = ngx_http_empty_handler;
  
      if (b->pos < b->last) {
  
          ngx_log_debug0(NGX_LOG_DEBUG_HTTP, c->log, 0, "pipelined request");
  
          c->log->action = "reading client pipelined request line";
  
          r = ngx_http_create_request(c);
          if (r == NULL) {
              ngx_http_close_connection(c);
              return;
          }
  
          r->pipeline = 1;
  
          c->data = r;
  
          c->sent = 0;
          c->destroyed = 0;
  
          if (rev->timer_set) {
              ngx_del_timer(rev);
          }
  
          rev->handler = ngx_http_process_request_line;
          ngx_post_event(rev, &ngx_posted_events);
          return;
      }
  
      /*
       * To keep a memory footprint as small as possible for an idle keepalive
       * connection we try to free c->buffer's memory if it was allocated outside
       * the c->pool.  The large header buffers are always allocated outside the
       * c->pool and are freed too.
       */
  
      b = c->buffer;
  
      if (ngx_pfree(c->pool, b->start) == NGX_OK) {
  
          /*
           * the special note for ngx_http_keepalive_handler() that
           * c->buffer's memory was freed
           */
  
          b->pos = NULL;
  
      } else {
          b->pos = b->start;
          b->last = b->start;
      }
  
      ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0, "hc free: %p",
                     hc->free);
  
      if (hc->free) {
          for (cl = hc->free; cl; /* void */) {
              ln = cl;
              cl = cl->next;
              ngx_pfree(c->pool, ln->buf->start);
              ngx_free_chain(c->pool, ln);
          }
  
          hc->free = NULL;
      }
  
      ngx_log_debug2(NGX_LOG_DEBUG_HTTP, c->log, 0, "hc busy: %p %i",
                     hc->busy, hc->nbusy);
  
      if (hc->busy) {
          for (cl = hc->busy; cl; /* void */) {
              ln = cl;
              cl = cl->next;
              ngx_pfree(c->pool, ln->buf->start);
              ngx_free_chain(c->pool, ln);
          }
  
          hc->busy = NULL;
          hc->nbusy = 0;
      }
  
  #if (NGX_HTTP_SSL)
      if (c->ssl) {
          ngx_ssl_free_buffer(c);
      }
  #endif
  
      rev->handler = ngx_http_keepalive_handler;
  
      if (wev->active && (ngx_event_flags & NGX_USE_LEVEL_EVENT)) {
          if (ngx_del_event(wev, NGX_WRITE_EVENT, 0) != NGX_OK) {
              ngx_http_close_connection(c);
              return;
          }
      }
  
      c->log->action = "keepalive";
  
      if (c->tcp_nopush == NGX_TCP_NOPUSH_SET) {
          if (ngx_tcp_push(c->fd) == -1) {
              ngx_connection_error(c, ngx_socket_errno, ngx_tcp_push_n " failed");
              ngx_http_close_connection(c);
              return;
          }
  
          c->tcp_nopush = NGX_TCP_NOPUSH_UNSET;
          tcp_nodelay = ngx_tcp_nodelay_and_tcp_nopush ? 1 : 0;
  
      } else {
          tcp_nodelay = 1;
      }
  
      if (tcp_nodelay && clcf->tcp_nodelay && ngx_tcp_nodelay(c) != NGX_OK) {
          ngx_http_close_connection(c);
          return;
      }
  
  #if 0
      /* if ngx_http_request_t was freed then we need some other place */
      r->http_state = NGX_HTTP_KEEPALIVE_STATE;
  #endif
  
      c->idle = 1;
      ngx_reusable_connection(c, 1);
  
      ngx_add_timer(rev, clcf->keepalive_timeout);
  
      if (rev->ready) {
          ngx_post_event(rev, &ngx_posted_events);
      }
  }
  
  
  static void
  ngx_http_keepalive_handler(ngx_event_t *rev)
  {
      size_t             size;
      ssize_t            n;
      ngx_buf_t         *b;
      ngx_connection_t  *c;
  
      c = rev->data;
  
      ngx_log_debug0(NGX_LOG_DEBUG_HTTP, c->log, 0, "http keepalive handler");
  
      if (rev->timedout || c->close) {
          ngx_http_close_connection(c);
          return;
      }
  
  #if (NGX_HAVE_KQUEUE)
  
      if (ngx_event_flags & NGX_USE_KQUEUE_EVENT) {
          if (rev->pending_eof) {
              c->log->handler = NULL;
              ngx_log_error(NGX_LOG_INFO, c->log, rev->kq_errno,
                            "kevent() reported that client %V closed "
                            "keepalive connection", &c->addr_text);
  #if (NGX_HTTP_SSL)
              if (c->ssl) {
                  c->ssl->no_send_shutdown = 1;
              }
  #endif
              ngx_http_close_connection(c);
              return;
          }
      }
  
  #endif
  
      b = c->buffer;
      size = b->end - b->start;
  
      if (b->pos == NULL) {
  
          /*
           * The c->buffer's memory was freed by ngx_http_set_keepalive().
           * However, the c->buffer->start and c->buffer->end were not changed
           * to keep the buffer size.
           */
  
          b->pos = ngx_palloc(c->pool, size);
          if (b->pos == NULL) {
              ngx_http_close_connection(c);
              return;
          }
  
          b->start = b->pos;
          b->last = b->pos;
          b->end = b->pos + size;
      }
  
      /*
       * MSIE closes a keepalive connection with RST flag
       * so we ignore ECONNRESET here.
       */
  
      c->log_error = NGX_ERROR_IGNORE_ECONNRESET;
      ngx_set_socket_errno(0);
  
      n = c->recv(c, b->last, size);
      c->log_error = NGX_ERROR_INFO;
  
      if (n == NGX_AGAIN) {
          if (ngx_handle_read_event(rev, 0) != NGX_OK) {
              ngx_http_close_connection(c);
              return;
          }
  
          /*
           * Like ngx_http_set_keepalive() we are trying to not hold
           * c->buffer's memory for a keepalive connection.
           */
  
          if (ngx_pfree(c->pool, b->start) == NGX_OK) {
  
              /*
               * the special note that c->buffer's memory was freed
               */
  
              b->pos = NULL;
          }
  
          return;
      }
  
      if (n == NGX_ERROR) {
          ngx_http_close_connection(c);
          return;
      }
  
      c->log->handler = NULL;
  
      if (n == 0) {
          ngx_log_error(NGX_LOG_INFO, c->log, ngx_socket_errno,
                        "client %V closed keepalive connection", &c->addr_text);
          ngx_http_close_connection(c);
          return;
      }
  
      b->last += n;
  
      c->log->handler = ngx_http_log_error;
      c->log->action = "reading client request line";
  
      c->idle = 0;
      ngx_reusable_connection(c, 0);
  
      c->data = ngx_http_create_request(c);
      if (c->data == NULL) {
          ngx_http_close_connection(c);
          return;
      }
  
      c->sent = 0;
      c->destroyed = 0;
  
      ngx_del_timer(rev);
  
      rev->handler = ngx_http_process_request_line;
      ngx_http_process_request_line(rev);
  }
  
  
  static void
  ngx_http_set_lingering_close(ngx_http_request_t *r)
  {
      ngx_event_t               *rev, *wev;
      ngx_connection_t          *c;
      ngx_http_core_loc_conf_t  *clcf;
  
      c = r->connection;
  
      clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);
  
      rev = c->read;
      rev->handler = ngx_http_lingering_close_handler;
  
      r->lingering_time = ngx_time() + (time_t) (clcf->lingering_time / 1000);
      ngx_add_timer(rev, clcf->lingering_timeout);
  
      if (ngx_handle_read_event(rev, 0) != NGX_OK) {
          ngx_http_close_request(r, 0);
          return;
      }
  
      wev = c->write;
      wev->handler = ngx_http_empty_handler;
  
      if (wev->active && (ngx_event_flags & NGX_USE_LEVEL_EVENT)) {
          if (ngx_del_event(wev, NGX_WRITE_EVENT, 0) != NGX_OK) {
              ngx_http_close_request(r, 0);
              return;
          }
      }
  
      if (ngx_shutdown_socket(c->fd, NGX_WRITE_SHUTDOWN) == -1) {
          ngx_connection_error(c, ngx_socket_errno,
                               ngx_shutdown_socket_n " failed");
          ngx_http_close_request(r, 0);
          return;
      }
  
      if (rev->ready) {
          ngx_http_lingering_close_handler(rev);
      }
  }
  
  
  static void
  ngx_http_lingering_close_handler(ngx_event_t *rev)
  {
      ssize_t                    n;
      ngx_msec_t                 timer;
      ngx_connection_t          *c;
      ngx_http_request_t        *r;
      ngx_http_core_loc_conf_t  *clcf;
      u_char                     buffer[NGX_HTTP_LINGERING_BUFFER_SIZE];
  
      c = rev->data;
      r = c->data;
  
      ngx_log_debug0(NGX_LOG_DEBUG_HTTP, c->log, 0,
                     "http lingering close handler");
  
      if (rev->timedout) {
          ngx_http_close_request(r, 0);
          return;
      }
  
      timer = (ngx_msec_t) r->lingering_time - (ngx_msec_t) ngx_time();
      if ((ngx_msec_int_t) timer <= 0) {
          ngx_http_close_request(r, 0);
          return;
      }
  
      do {
          n = c->recv(c, buffer, NGX_HTTP_LINGERING_BUFFER_SIZE);
  
          ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0, "lingering read: %z", n);
  
          if (n == NGX_AGAIN) {
              break;
          }
  
          if (n == NGX_ERROR || n == 0) {
              ngx_http_close_request(r, 0);
              return;
          }
  
      } while (rev->ready);
  
      if (ngx_handle_read_event(rev, 0) != NGX_OK) {
          ngx_http_close_request(r, 0);
          return;
      }
  
      clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);
  
      timer *= 1000;
  
      if (timer > clcf->lingering_timeout) {
          timer = clcf->lingering_timeout;
      }
  
      ngx_add_timer(rev, timer);
  }
  
  
  void
  ngx_http_empty_handler(ngx_event_t *wev)
  {
      ngx_log_debug0(NGX_LOG_DEBUG_HTTP, wev->log, 0, "http empty handler");
  
      return;
  }
  
  
  void
  ngx_http_request_empty_handler(ngx_http_request_t *r)
  {
      ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                     "http request empty handler");
  
      return;
  }
  
  
  ngx_int_t
  ngx_http_send_special(ngx_http_request_t *r, ngx_uint_t flags)
  {
      ngx_buf_t    *b;
      ngx_chain_t   out;
  
      b = ngx_calloc_buf(r->pool);
      if (b == NULL) {
          return NGX_ERROR;
      }
  
      if (flags & NGX_HTTP_LAST) {
  
          if (r == r->main && !r->post_action) {
              b->last_buf = 1;
  
          } else {
              b->sync = 1;
              b->last_in_chain = 1;
          }
      }
  
      if (flags & NGX_HTTP_FLUSH) {
          b->flush = 1;
      }
  
      out.buf = b;
      out.next = NULL;
  
      return ngx_http_output_filter(r, &out);
  }
  
  
  static ngx_int_t
  ngx_http_post_action(ngx_http_request_t *r)
  {
      ngx_http_core_loc_conf_t  *clcf;
  
      clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);
  
      if (clcf->post_action.data == NULL) {
          return NGX_DECLINED;
      }
  
      if (r->post_action && r->uri_changes == 0) {
          return NGX_DECLINED;
      }
  
      ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                     "post action: \"%V\"", &clcf->post_action);
  
      r->main->count--;
  
      r->http_version = NGX_HTTP_VERSION_9;
      r->header_only = 1;
      r->post_action = 1;
  
      r->read_event_handler = ngx_http_block_reading;
  
      if (clcf->post_action.data[0] == '/') {
          ngx_http_internal_redirect(r, &clcf->post_action, NULL);
  
      } else {
          ngx_http_named_location(r, &clcf->post_action);
      }
  
      return NGX_OK;
  }
  
  
  static void
  ngx_http_close_request(ngx_http_request_t *r, ngx_int_t rc)
  {
      ngx_connection_t  *c;
  
      r = r->main;
      c = r->connection;
  
      ngx_log_debug2(NGX_LOG_DEBUG_HTTP, c->log, 0,
                     "http request count:%d blk:%d", r->count, r->blocked);
  
      if (r->count == 0) {
          ngx_log_error(NGX_LOG_ALERT, c->log, 0, "http request count is zero");
      }
  
      r->count--;
  
      if (r->count || r->blocked) {
          return;
      }
  
  #if (NGX_HTTP_V2)
      if (r->stream) {
          ngx_http_v2_close_stream(r->stream, rc);
          return;
      }
  #endif
  
      ngx_http_free_request(r, rc);
      ngx_http_close_connection(c);
  }
  
  
  void
  ngx_http_free_request(ngx_http_request_t *r, ngx_int_t rc)
  {
      ngx_log_t                 *log;
      ngx_pool_t                *pool;
      struct linger              linger;
      ngx_http_cleanup_t        *cln;
      ngx_http_log_ctx_t        *ctx;
      ngx_http_core_loc_conf_t  *clcf;
  
      log = r->connection->log;
  
      ngx_log_debug0(NGX_LOG_DEBUG_HTTP, log, 0, "http close request");
  
      if (r->pool == NULL) {
          ngx_log_error(NGX_LOG_ALERT, log, 0, "http request already closed");
          return;
      }
  
      cln = r->cleanup;
      r->cleanup = NULL;
  
      while (cln) {
          if (cln->handler) {
              cln->handler(cln->data);
          }
  
          cln = cln->next;
      }
  
  #if (NGX_STAT_STUB)
  
      if (r->stat_reading) {
          (void) ngx_atomic_fetch_add(ngx_stat_reading, -1);
      }
  
      if (r->stat_writing) {
          (void) ngx_atomic_fetch_add(ngx_stat_writing, -1);
      }
  
  #endif
  
      if (rc > 0 && (r->headers_out.status == 0 || r->connection->sent == 0)) {
          r->headers_out.status = rc;
      }
  
      if (!r->logged) {
          log->action = "logging request";
  
          ngx_http_log_request(r);
      }
  
      log->action = "closing request";
  
      if (r->connection->timedout) {
          clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);
  
          if (clcf->reset_timedout_connection) {
              linger.l_onoff = 1;
              linger.l_linger = 0;
  
              if (setsockopt(r->connection->fd, SOL_SOCKET, SO_LINGER,
                             (const void *) &linger, sizeof(struct linger)) == -1)
              {
                  ngx_log_error(NGX_LOG_ALERT, log, ngx_socket_errno,
                                "setsockopt(SO_LINGER) failed");
              }
          }
      }
  
      /* the various request strings were allocated from r->pool */
      ctx = log->data;
      ctx->request = NULL;
  
      r->request_line.len = 0;
  
      r->connection->destroyed = 1;
  
      /*
       * Setting r->pool to NULL will increase probability to catch double close
       * of request since the request object is allocated from its own pool.
       */
  
      pool = r->pool;
      r->pool = NULL;
  
      ngx_destroy_pool(pool);
  }
  
  
  static void
  ngx_http_log_request(ngx_http_request_t *r)
  {
      ngx_uint_t                  i, n;
      ngx_http_handler_pt        *log_handler;
      ngx_http_core_main_conf_t  *cmcf;
  
      cmcf = ngx_http_get_module_main_conf(r, ngx_http_core_module);
  
      log_handler = cmcf->phases[NGX_HTTP_LOG_PHASE].handlers.elts;
      n = cmcf->phases[NGX_HTTP_LOG_PHASE].handlers.nelts;
  
      for (i = 0; i < n; i++) {
          log_handler[i](r);
      }
  }
  
  
  void
  ngx_http_close_connection(ngx_connection_t *c)
  {
      ngx_pool_t  *pool;
  
      ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0,
                     "close http connection: %d", c->fd);
  
  #if (NGX_HTTP_SSL)
  
      if (c->ssl) {
          if (ngx_ssl_shutdown(c) == NGX_AGAIN) {
              c->ssl->handler = ngx_http_close_connection;
              return;
          }
      }
  
  #endif
  
  #if (NGX_STAT_STUB)
      (void) ngx_atomic_fetch_add(ngx_stat_active, -1);
  #endif
  
      c->destroyed = 1;
  
      pool = c->pool;
  
      ngx_close_connection(c);
  
      ngx_destroy_pool(pool);
  }
  
  
  static u_char *
  ngx_http_log_error(ngx_log_t *log, u_char *buf, size_t len)
  {
      u_char              *p;
      ngx_http_request_t  *r;
      ngx_http_log_ctx_t  *ctx;
  
      if (log->action) {
          p = ngx_snprintf(buf, len, " while %s", log->action);
          len -= p - buf;
          buf = p;
      }
  
      ctx = log->data;
  
      p = ngx_snprintf(buf, len, ", client: %V", &ctx->connection->addr_text);
      len -= p - buf;
  
      r = ctx->request;
  
      if (r) {
          return r->log_handler(r, ctx->current_request, p, len);
  
      } else {
          p = ngx_snprintf(p, len, ", server: %V",
                           &ctx->connection->listening->addr_text);
      }
  
      return p;
  }
  
  
  static u_char *
  ngx_http_log_error_handler(ngx_http_request_t *r, ngx_http_request_t *sr,
      u_char *buf, size_t len)
  {
      char                      *uri_separator;
      u_char                    *p;
      ngx_http_upstream_t       *u;
      ngx_http_core_srv_conf_t  *cscf;
  
      cscf = ngx_http_get_module_srv_conf(r, ngx_http_core_module);
  
      p = ngx_snprintf(buf, len, ", server: %V", &cscf->server_name);
      len -= p - buf;
      buf = p;
  
      if (r->request_line.data == NULL && r->request_start) {
          for (p = r->request_start; p < r->header_in->last; p++) {
              if (*p == CR || *p == LF) {
                  break;
              }
          }
  
          r->request_line.len = p - r->request_start;
          r->request_line.data = r->request_start;
      }
  
      if (r->request_line.len) {
          p = ngx_snprintf(buf, len, ", request: \"%V\"", &r->request_line);
          len -= p - buf;
          buf = p;
      }
  
      if (r != sr) {
          p = ngx_snprintf(buf, len, ", subrequest: \"%V\"", &sr->uri);
          len -= p - buf;
          buf = p;
      }
  
      u = sr->upstream;
  
      if (u && u->peer.name) {
  
          uri_separator = "";
  
  #if (NGX_HAVE_UNIX_DOMAIN)
          if (u->peer.sockaddr && u->peer.sockaddr->sa_family == AF_UNIX) {
              uri_separator = ":";
          }
  #endif
  
          p = ngx_snprintf(buf, len, ", upstream: \"%V%V%s%V\"",
                           &u->schema, u->peer.name,
                           uri_separator, &u->uri);
          len -= p - buf;
          buf = p;
      }
  
      if (r->headers_in.host) {
          p = ngx_snprintf(buf, len, ", host: \"%V\"",
                           &r->headers_in.host->value);
          len -= p - buf;
          buf = p;
      }
  
      if (r->headers_in.referer) {
          p = ngx_snprintf(buf, len, ", referrer: \"%V\"",
                           &r->headers_in.referer->value);
          buf = p;
      }
  
      return buf;
  }
  