text: 
  /*
   * Copyright (C) Igor Sysoev
   * Copyright (C) Nginx, Inc.
   */
  
  
  #include <ngx_config.h>
  #include <ngx_core.h>
  #include <ngx_http.h>
  
  #if (NGX_ZLIB)
  #include <zlib.h>
  #endif
  
  
  typedef struct ngx_http_log_op_s  ngx_http_log_op_t;
  
  typedef u_char *(*ngx_http_log_op_run_pt) (ngx_http_request_t *r, u_char *buf,
      ngx_http_log_op_t *op);
  
  typedef size_t (*ngx_http_log_op_getlen_pt) (ngx_http_request_t *r,
      uintptr_t data);
  
  
  struct ngx_http_log_op_s {
      size_t                      len;
      ngx_http_log_op_getlen_pt   getlen;
      ngx_http_log_op_run_pt      run;
      uintptr_t                   data;
  };
  
  
  typedef struct {
      ngx_str_t                   name;
      ngx_array_t                *flushes;
      ngx_array_t                *ops;        /* array of ngx_http_log_op_t */
  } ngx_http_log_fmt_t;
  
  
  typedef struct {
      ngx_array_t                 formats;    /* array of ngx_http_log_fmt_t */
      ngx_uint_t                  combined_used; /* unsigned  combined_used:1 */
  } ngx_http_log_main_conf_t;
  
  
  typedef struct {
      u_char                     *start;
      u_char                     *pos;
      u_char                     *last;
  
      ngx_event_t                *event;
      ngx_msec_t                  flush;
      ngx_int_t                   gzip;
  } ngx_http_log_buf_t;
  
  
  typedef struct {
      ngx_array_t                *lengths;
      ngx_array_t                *values;
  } ngx_http_log_script_t;
  
  
  typedef struct {
      ngx_open_file_t            *file;
      ngx_http_log_script_t      *script;
      time_t                      disk_full_time;
      time_t                      error_log_time;
      ngx_syslog_peer_t          *syslog_peer;
      ngx_http_log_fmt_t         *format;
      ngx_http_complex_value_t   *filter;
  } ngx_http_log_t;
  
  
  typedef struct {
      ngx_array_t                *logs;       /* array of ngx_http_log_t */
  
      ngx_open_file_cache_t      *open_file_cache;
      time_t                      open_file_cache_valid;
      ngx_uint_t                  open_file_cache_min_uses;
  
      ngx_flag_t                  escape_non_ascii;
  
      ngx_uint_t                  off;        /* unsigned  off:1 */
  } ngx_http_log_loc_conf_t;
  
  
  typedef struct {
      ngx_str_t                   name;
      size_t                      len;
      ngx_http_log_op_run_pt      run;
  } ngx_http_log_var_t;
  
  
  static void ngx_http_log_write(ngx_http_request_t *r, ngx_http_log_t *log,
      u_char *buf, size_t len);
  static ssize_t ngx_http_log_script_write(ngx_http_request_t *r,
      ngx_http_log_script_t *script, u_char **name, u_char *buf, size_t len);
  
  #if (NGX_ZLIB)
  static ssize_t ngx_http_log_gzip(ngx_fd_t fd, u_char *buf, size_t len,
      ngx_int_t level, ngx_log_t *log);
  
  static void *ngx_http_log_gzip_alloc(void *opaque, u_int items, u_int size);
  static void ngx_http_log_gzip_free(void *opaque, void *address);
  #endif
  
  static void ngx_http_log_flush(ngx_open_file_t *file, ngx_log_t *log);
  static void ngx_http_log_flush_handler(ngx_event_t *ev);
  
  static u_char *ngx_http_log_pipe(ngx_http_request_t *r, u_char *buf,
      ngx_http_log_op_t *op);
  static u_char *ngx_http_log_time(ngx_http_request_t *r, u_char *buf,
      ngx_http_log_op_t *op);
  static u_char *ngx_http_log_iso8601(ngx_http_request_t *r, u_char *buf,
      ngx_http_log_op_t *op);
  static u_char *ngx_http_log_msec(ngx_http_request_t *r, u_char *buf,
      ngx_http_log_op_t *op);
  static u_char *ngx_http_log_request_time(ngx_http_request_t *r, u_char *buf,
      ngx_http_log_op_t *op);
  static u_char *ngx_http_log_status(ngx_http_request_t *r, u_char *buf,
      ngx_http_log_op_t *op);
  static u_char *ngx_http_log_bytes_sent(ngx_http_request_t *r, u_char *buf,
      ngx_http_log_op_t *op);
  static u_char *ngx_http_log_body_bytes_sent(ngx_http_request_t *r,
      u_char *buf, ngx_http_log_op_t *op);
  static u_char *ngx_http_log_request_length(ngx_http_request_t *r, u_char *buf,
      ngx_http_log_op_t *op);
  
  static ngx_int_t ngx_http_log_variable_compile(ngx_conf_t *cf,
      ngx_http_log_op_t *op, ngx_str_t *value, ngx_uint_t json);
  static size_t ngx_http_log_variable_getlen(ngx_http_request_t *r,
      uintptr_t data);
  static u_char *ngx_http_log_variable(ngx_http_request_t *r, u_char *buf,
      ngx_http_log_op_t *op);
  static uintptr_t ngx_http_log_escape(ngx_http_log_loc_conf_t *lcf, u_char *dst,
      u_char *src, size_t size);
  static size_t ngx_http_log_json_variable_getlen(ngx_http_request_t *r,
      uintptr_t data);
  static u_char *ngx_http_log_json_variable(ngx_http_request_t *r, u_char *buf,
      ngx_http_log_op_t *op);
  
  
  static void *ngx_http_log_create_main_conf(ngx_conf_t *cf);
  static void *ngx_http_log_create_loc_conf(ngx_conf_t *cf);
  static char *ngx_http_log_merge_loc_conf(ngx_conf_t *cf, void *parent,
      void *child);
  static char *ngx_http_log_set_log(ngx_conf_t *cf, ngx_command_t *cmd,
      void *conf);
  static char *ngx_http_log_set_format(ngx_conf_t *cf, ngx_command_t *cmd,
      void *conf);
  static char *ngx_http_log_compile_format(ngx_conf_t *cf,
      ngx_array_t *flushes, ngx_array_t *ops, ngx_array_t *args, ngx_uint_t s);
  static char *ngx_http_log_open_file_cache(ngx_conf_t *cf, ngx_command_t *cmd,
      void *conf);
  static ngx_int_t ngx_http_log_init(ngx_conf_t *cf);
  
  
  static ngx_command_t  ngx_http_log_commands[] = {
  
      { ngx_string("log_format"),
        NGX_HTTP_MAIN_CONF|NGX_CONF_2MORE,
        ngx_http_log_set_format,
        NGX_HTTP_MAIN_CONF_OFFSET,
        0,
        NULL },
  
      { ngx_string("access_log"),
        NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_HTTP_LIF_CONF
                          |NGX_HTTP_LMT_CONF|NGX_CONF_1MORE,
        ngx_http_log_set_log,
        NGX_HTTP_LOC_CONF_OFFSET,
        0,
        NULL },
  
      { ngx_string("open_log_file_cache"),
        NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1234,
        ngx_http_log_open_file_cache,
        NGX_HTTP_LOC_CONF_OFFSET,
        0,
        NULL },
  
      { ngx_string("log_escape_non_ascii"),
        NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_FLAG,
        ngx_conf_set_flag_slot,
        NGX_HTTP_LOC_CONF_OFFSET,
        offsetof(ngx_http_log_loc_conf_t, escape_non_ascii),
        NULL },
  
        ngx_null_command
  };
  
  
  static ngx_http_module_t  ngx_http_log_module_ctx = {
      NULL,                                  /* preconfiguration */
      ngx_http_log_init,                     /* postconfiguration */
  
      ngx_http_log_create_main_conf,         /* create main configuration */
      NULL,                                  /* init main configuration */
  
      NULL,                                  /* create server configuration */
      NULL,                                  /* merge server configuration */
  
      ngx_http_log_create_loc_conf,          /* create location configuration */
      ngx_http_log_merge_loc_conf            /* merge location configuration */
  };
  
  
  ngx_module_t  ngx_http_log_module = {
      NGX_MODULE_V1,
      &ngx_http_log_module_ctx,              /* module context */
      ngx_http_log_commands,                 /* module directives */
      NGX_HTTP_MODULE,                       /* module type */
      NULL,                                  /* init master */
      NULL,                                  /* init module */
      NULL,                                  /* init process */
      NULL,                                  /* init thread */
      NULL,                                  /* exit thread */
      NULL,                                  /* exit process */
      NULL,                                  /* exit master */
      NGX_MODULE_V1_PADDING
  };
  
  
  static ngx_str_t  ngx_http_access_log = ngx_string(NGX_HTTP_LOG_PATH);
  
  
  static ngx_str_t  ngx_http_combined_fmt =
      ngx_string("$remote_addr - $remote_user [$time_local] "
                 "\"$request\" $status $body_bytes_sent "
                 "\"$http_referer\" \"$http_user_agent\"");
  
  
  static ngx_http_log_var_t  ngx_http_log_vars[] = {
      { ngx_string("pipe"), 1, ngx_http_log_pipe },
      { ngx_string("time_local"), sizeof("28/Sep/1970:12:00:00 +0600") - 1,
                            ngx_http_log_time },
      { ngx_string("time_iso8601"), sizeof("1970-09-28T12:00:00+06:00") - 1,
                            ngx_http_log_iso8601 },
      { ngx_string("msec"), NGX_TIME_T_LEN + 4, ngx_http_log_msec },
      { ngx_string("request_time"), NGX_TIME_T_LEN + 4,
                            ngx_http_log_request_time },
      { ngx_string("status"), NGX_INT_T_LEN, ngx_http_log_status },
      { ngx_string("bytes_sent"), NGX_OFF_T_LEN, ngx_http_log_bytes_sent },
      { ngx_string("body_bytes_sent"), NGX_OFF_T_LEN,
                            ngx_http_log_body_bytes_sent },
      { ngx_string("request_length"), NGX_SIZE_T_LEN,
                            ngx_http_log_request_length },
  
      { ngx_null_string, 0, NULL }
  };
  
  
  static ngx_int_t
  ngx_http_log_handler(ngx_http_request_t *r)
  {
      u_char                   *line, *p;
      size_t                    len, size;
      ssize_t                   n;
      ngx_str_t                 val;
      ngx_uint_t                i, l;
      ngx_http_log_t           *log;
      ngx_http_log_op_t        *op;
      ngx_http_log_buf_t       *buffer;
      ngx_http_log_loc_conf_t  *lcf;
  
      ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                     "http log handler");
  
      lcf = ngx_http_get_module_loc_conf(r, ngx_http_log_module);
  
      if (lcf->off) {
          return NGX_OK;
      }
  
      log = lcf->logs->elts;
      for (l = 0; l < lcf->logs->nelts; l++) {
  
          if (log[l].filter) {
              if (ngx_http_complex_value(r, log[l].filter, &val) != NGX_OK) {
                  return NGX_ERROR;
              }
  
              if (val.len == 0 || (val.len == 1 && val.data[0] == '0')) {
                  continue;
              }
          }
  
          if (ngx_time() == log[l].disk_full_time) {
  
              /*
               * on FreeBSD writing to a full filesystem with enabled softupdates
               * may block process for much longer time than writing to non-full
               * filesystem, so we skip writing to a log for one second
               */
  
              continue;
          }
  
          ngx_http_script_flush_no_cacheable_variables(r, log[l].format->flushes);
  
          len = 0;
          op = log[l].format->ops->elts;
          for (i = 0; i < log[l].format->ops->nelts; i++) {
              if (op[i].len == 0) {
                  len += op[i].getlen(r, op[i].data);
  
              } else {
                  len += op[i].len;
              }
          }
  
          if (log[l].syslog_peer) {
  
              /* length of syslog's PRI and HEADER message parts */
              len += sizeof("<255>Jan 01 00:00:00 ") - 1
                     + ngx_cycle->hostname.len + 1
                     + log[l].syslog_peer->tag.len + 2;
  
              goto alloc_line;
          }
  
          len += NGX_LINEFEED_SIZE;
  
          buffer = log[l].file ? log[l].file->data : NULL;
  
          if (buffer) {
  
              if (len > (size_t) (buffer->last - buffer->pos)) {
  
                  ngx_http_log_write(r, &log[l], buffer->start,
                                     buffer->pos - buffer->start);
  
                  buffer->pos = buffer->start;
              }
  
              if (len <= (size_t) (buffer->last - buffer->pos)) {
  
                  p = buffer->pos;
  
                  if (buffer->event && p == buffer->start) {
                      ngx_add_timer(buffer->event, buffer->flush);
                  }
  
                  for (i = 0; i < log[l].format->ops->nelts; i++) {
                      p = op[i].run(r, p, &op[i]);
                  }
  
                  ngx_linefeed(p);
  
                  buffer->pos = p;
  
                  continue;
              }
  
              if (buffer->event && buffer->event->timer_set) {
                  ngx_del_timer(buffer->event);
              }
          }
  
      alloc_line:
  
          line = ngx_pnalloc(r->pool, len);
          if (line == NULL) {
              return NGX_ERROR;
          }
  
          p = line;
  
          if (log[l].syslog_peer) {
              p = ngx_syslog_add_header(log[l].syslog_peer, line);
          }
  
          for (i = 0; i < log[l].format->ops->nelts; i++) {
              p = op[i].run(r, p, &op[i]);
          }
  
          if (log[l].syslog_peer) {
  
              size = p - line;
  
              n = ngx_syslog_send(log[l].syslog_peer, line, size);
  
              if (n < 0) {
                  ngx_log_error(NGX_LOG_WARN, r->connection->log, 0,
                                "send() to syslog failed");
  
              } else if ((size_t) n != size) {
                  ngx_log_error(NGX_LOG_WARN, r->connection->log, 0,
                                "send() to syslog has written only %z of %uz",
                                n, size);
              }
  
              continue;
          }
  
          ngx_linefeed(p);
  
          ngx_http_log_write(r, &log[l], line, p - line);
      }
  
      return NGX_OK;
  }
  
  
  static void
  ngx_http_log_write(ngx_http_request_t *r, ngx_http_log_t *log, u_char *buf,
      size_t len)
  {
      u_char              *name;
      time_t               now;
      ssize_t              n;
      ngx_err_t            err;
  #if (NGX_ZLIB)
      ngx_http_log_buf_t  *buffer;
  #endif
  
      if (log->script == NULL) {
          name = log->file->name.data;
  
  #if (NGX_ZLIB)
          buffer = log->file->data;
  
          if (buffer && buffer->gzip) {
              n = ngx_http_log_gzip(log->file->fd, buf, len, buffer->gzip,
                                    r->connection->log);
          } else {
              n = ngx_write_fd(log->file->fd, buf, len);
          }
  #else
          n = ngx_write_fd(log->file->fd, buf, len);
  #endif
  
      } else {
          name = NULL;
          n = ngx_http_log_script_write(r, log->script, &name, buf, len);
      }
  
      if (n == (ssize_t) len) {
          return;
      }
  
      now = ngx_time();
  
      if (n == -1) {
          err = ngx_errno;
  
          if (err == NGX_ENOSPC) {
              log->disk_full_time = now;
          }
  
          if (now - log->error_log_time > 59) {
              ngx_log_error(NGX_LOG_ALERT, r->connection->log, err,
                            ngx_write_fd_n " to \"%s\" failed", name);
  
              log->error_log_time = now;
          }
  
          return;
      }
  
      if (now - log->error_log_time > 59) {
          ngx_log_error(NGX_LOG_ALERT, r->connection->log, 0,
                        ngx_write_fd_n " to \"%s\" was incomplete: %z of %uz",
                        name, n, len);
  
          log->error_log_time = now;
      }
  }
  
  
  static ssize_t
  ngx_http_log_script_write(ngx_http_request_t *r, ngx_http_log_script_t *script,
      u_char **name, u_char *buf, size_t len)
  {
      size_t                     root;
      ssize_t                    n;
      ngx_str_t                  log, path;
      ngx_open_file_info_t       of;
      ngx_http_log_loc_conf_t   *llcf;
      ngx_http_core_loc_conf_t  *clcf;
  
      clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);
  
      if (!r->root_tested) {
  
          /* test root directory existence */
  
          if (ngx_http_map_uri_to_path(r, &path, &root, 0) == NULL) {
              /* simulate successful logging */
              return len;
          }
  
          path.data[root] = '\0';
  
          ngx_memzero(&of, sizeof(ngx_open_file_info_t));
  
          of.valid = clcf->open_file_cache_valid;
          of.min_uses = clcf->open_file_cache_min_uses;
          of.test_dir = 1;
          of.test_only = 1;
          of.errors = clcf->open_file_cache_errors;
          of.events = clcf->open_file_cache_events;
  
          if (ngx_http_set_disable_symlinks(r, clcf, &path, &of) != NGX_OK) {
              /* simulate successful logging */
              return len;
          }
  
          if (ngx_open_cached_file(clcf->open_file_cache, &path, &of, r->pool)
              != NGX_OK)
          {
              if (of.err == 0) {
                  /* simulate successful logging */
                  return len;
              }
  
              ngx_log_error(NGX_LOG_ERR, r->connection->log, of.err,
                            "testing \"%s\" existence failed", path.data);
  
              /* simulate successful logging */
              return len;
          }
  
          if (!of.is_dir) {
              ngx_log_error(NGX_LOG_ERR, r->connection->log, NGX_ENOTDIR,
                            "testing \"%s\" existence failed", path.data);
  
              /* simulate successful logging */
              return len;
          }
      }
  
      if (ngx_http_script_run(r, &log, script->lengths->elts, 1,
                              script->values->elts)
          == NULL)
      {
          /* simulate successful logging */
          return len;
      }
  
      log.data[log.len - 1] = '\0';
      *name = log.data;
  
      ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                     "http log \"%s\"", log.data);
  
      llcf = ngx_http_get_module_loc_conf(r, ngx_http_log_module);
  
      ngx_memzero(&of, sizeof(ngx_open_file_info_t));
  
      of.log = 1;
      of.valid = llcf->open_file_cache_valid;
      of.min_uses = llcf->open_file_cache_min_uses;
      of.directio = NGX_OPEN_FILE_DIRECTIO_OFF;
  
      if (ngx_http_set_disable_symlinks(r, clcf, &log, &of) != NGX_OK) {
          /* simulate successful logging */
          return len;
      }
  
      if (ngx_open_cached_file(llcf->open_file_cache, &log, &of, r->pool)
          != NGX_OK)
      {
          if (of.err == 0) {
              /* simulate successful logging */
              return len;
          }
  
          ngx_log_error(NGX_LOG_CRIT, r->connection->log, ngx_errno,
                        "%s \"%s\" failed", of.failed, log.data);
          /* simulate successful logging */
          return len;
      }
  
      ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                     "http log #%d", of.fd);
  
      n = ngx_write_fd(of.fd, buf, len);
  
      return n;
  }
  
  
  #if (NGX_ZLIB)
  
  static ssize_t
  ngx_http_log_gzip(ngx_fd_t fd, u_char *buf, size_t len, ngx_int_t level,
      ngx_log_t *log)
  {
      int          rc, wbits, memlevel;
      u_char      *out;
      size_t       size;
      ssize_t      n;
      z_stream     zstream;
      ngx_err_t    err;
      ngx_pool_t  *pool;
  
      wbits = MAX_WBITS;
      memlevel = MAX_MEM_LEVEL - 1;
  
      while ((ssize_t) len < ((1 << (wbits - 1)) - 262)) {
          wbits--;
          memlevel--;
      }
  
      /*
       * This is a formula from deflateBound() for conservative upper bound of
       * compressed data plus 18 bytes of gzip wrapper.
       */
  
      size = len + ((len + 7) >> 3) + ((len + 63) >> 6) + 5 + 18;
  
      ngx_memzero(&zstream, sizeof(z_stream));
  
      pool = ngx_create_pool(256, log);
      if (pool == NULL) {
          /* simulate successful logging */
          return len;
      }
  
      pool->log = log;
  
      zstream.zalloc = ngx_http_log_gzip_alloc;
      zstream.zfree = ngx_http_log_gzip_free;
      zstream.opaque = pool;
  
      out = ngx_pnalloc(pool, size);
      if (out == NULL) {
          goto done;
      }
  
      zstream.next_in = buf;
      zstream.avail_in = len;
      zstream.next_out = out;
      zstream.avail_out = size;
  
      rc = deflateInit2(&zstream, (int) level, Z_DEFLATED, wbits + 16, memlevel,
                        Z_DEFAULT_STRATEGY);
  
      if (rc != Z_OK) {
          ngx_log_error(NGX_LOG_ALERT, log, 0, "deflateInit2() failed: %d", rc);
          goto done;
      }
  
      ngx_log_debug4(NGX_LOG_DEBUG_HTTP, log, 0,
                     "deflate in: ni:%p no:%p ai:%ud ao:%ud",
                     zstream.next_in, zstream.next_out,
                     zstream.avail_in, zstream.avail_out);
  
      rc = deflate(&zstream, Z_FINISH);
  
      if (rc != Z_STREAM_END) {
          ngx_log_error(NGX_LOG_ALERT, log, 0,
                        "deflate(Z_FINISH) failed: %d", rc);
          goto done;
      }
  
      ngx_log_debug5(NGX_LOG_DEBUG_HTTP, log, 0,
                     "deflate out: ni:%p no:%p ai:%ud ao:%ud rc:%d",
                     zstream.next_in, zstream.next_out,
                     zstream.avail_in, zstream.avail_out,
                     rc);
  
      size -= zstream.avail_out;
  
      rc = deflateEnd(&zstream);
  
      if (rc != Z_OK) {
          ngx_log_error(NGX_LOG_ALERT, log, 0, "deflateEnd() failed: %d", rc);
          goto done;
      }
  
      n = ngx_write_fd(fd, out, size);
  
      if (n != (ssize_t) size) {
          err = (n == -1) ? ngx_errno : 0;
  
          ngx_destroy_pool(pool);
  
          ngx_set_errno(err);
          return -1;
      }
  
  done:
  
      ngx_destroy_pool(pool);
  
      /* simulate successful logging */
      return len;
  }
  
  
  static void *
  ngx_http_log_gzip_alloc(void *opaque, u_int items, u_int size)
  {
      ngx_pool_t *pool = opaque;
  
      ngx_log_debug2(NGX_LOG_DEBUG_HTTP, pool->log, 0,
                     "gzip alloc: n:%ud s:%ud", items, size);
  
      return ngx_palloc(pool, items * size);
  }
  
  
  static void
  ngx_http_log_gzip_free(void *opaque, void *address)
  {
  #if 0
      ngx_pool_t *pool = opaque;
  
      ngx_log_debug1(NGX_LOG_DEBUG_HTTP, pool->log, 0, "gzip free: %p", address);
  #endif
  }
  
  #endif
  
  
  static void
  ngx_http_log_flush(ngx_open_file_t *file, ngx_log_t *log)
  {
      size_t               len;
      ssize_t              n;
      ngx_http_log_buf_t  *buffer;
  
      buffer = file->data;
  
      len = buffer->pos - buffer->start;
  
      if (len == 0) {
          return;
      }
  
  #if (NGX_ZLIB)
      if (buffer->gzip) {
          n = ngx_http_log_gzip(file->fd, buffer->start, len, buffer->gzip, log);
      } else {
          n = ngx_write_fd(file->fd, buffer->start, len);
      }
  #else
      n = ngx_write_fd(file->fd, buffer->start, len);
  #endif
  
      if (n == -1) {
          ngx_log_error(NGX_LOG_ALERT, log, ngx_errno,
                        ngx_write_fd_n " to \"%s\" failed",
                        file->name.data);
  
      } else if ((size_t) n != len) {
          ngx_log_error(NGX_LOG_ALERT, log, 0,
                        ngx_write_fd_n " to \"%s\" was incomplete: %z of %uz",
                        file->name.data, n, len);
      }
  
      buffer->pos = buffer->start;
  
      if (buffer->event && buffer->event->timer_set) {
          ngx_del_timer(buffer->event);
      }
  }
  
  
  static void
  ngx_http_log_flush_handler(ngx_event_t *ev)
  {
      ngx_log_debug0(NGX_LOG_DEBUG_EVENT, ev->log, 0,
                     "http log buffer flush handler");
  
      ngx_http_log_flush(ev->data, ev->log);
  }
  
  
  static u_char *
  ngx_http_log_copy_short(ngx_http_request_t *r, u_char *buf,
      ngx_http_log_op_t *op)
  {
      size_t     len;
      uintptr_t  data;
  
      len = op->len;
      data = op->data;
  
      while (len--) {
          *buf++ = (u_char) (data & 0xff);
          data >>= 8;
      }
  
      return buf;
  }
  
  
  static u_char *
  ngx_http_log_copy_long(ngx_http_request_t *r, u_char *buf,
      ngx_http_log_op_t *op)
  {
      return ngx_cpymem(buf, (u_char *) op->data, op->len);
  }
  
  
  static u_char *
  ngx_http_log_pipe(ngx_http_request_t *r, u_char *buf, ngx_http_log_op_t *op)
  {
      if (r->pipeline) {
          *buf = 'p';
      } else {
          *buf = '.';
      }
  
      return buf + 1;
  }
  
  
  static u_char *
  ngx_http_log_time(ngx_http_request_t *r, u_char *buf, ngx_http_log_op_t *op)
  {
      return ngx_cpymem(buf, ngx_cached_http_log_time.data,
                        ngx_cached_http_log_time.len);
  }
  
  static u_char *
  ngx_http_log_iso8601(ngx_http_request_t *r, u_char *buf, ngx_http_log_op_t *op)
  {
      return ngx_cpymem(buf, ngx_cached_http_log_iso8601.data,
                        ngx_cached_http_log_iso8601.len);
  }
  
  static u_char *
  ngx_http_log_msec(ngx_http_request_t *r, u_char *buf, ngx_http_log_op_t *op)
  {
      ngx_time_t  *tp;
  
      tp = ngx_timeofday();
  
      return ngx_sprintf(buf, "%T.%03M", tp->sec, tp->msec);
  }
  
  
  static u_char *
  ngx_http_log_request_time(ngx_http_request_t *r, u_char *buf,
      ngx_http_log_op_t *op)
  {
      ngx_time_t      *tp;
      ngx_msec_int_t   ms;
  
      tp = ngx_timeofday();
  
      ms = (ngx_msec_int_t)
               ((tp->sec - r->start_sec) * 1000 + (tp->msec - r->start_msec));
      ms = ngx_max(ms, 0);
  
      return ngx_sprintf(buf, "%T.%03M", (time_t) ms / 1000, ms % 1000);
  }
  
  
  static u_char *
  ngx_http_log_status(ngx_http_request_t *r, u_char *buf, ngx_http_log_op_t *op)
  {
      ngx_uint_t  status;
  
      if (r->err_status) {
          status = r->err_status;
  
      } else if (r->headers_out.status) {
          status = r->headers_out.status;
  
      } else if (r->http_version == NGX_HTTP_VERSION_9) {
          status = 9;
  
      } else {
          status = 0;
      }
  
      return ngx_sprintf(buf, "%03ui", status);
  }
  
  
  static u_char *
  ngx_http_log_bytes_sent(ngx_http_request_t *r, u_char *buf,
      ngx_http_log_op_t *op)
  {
      return ngx_sprintf(buf, "%O", r->connection->sent);
  }
  
  
  /*
   * although there is a real $body_bytes_sent variable,
   * this log operation code function is more optimized for logging
   */
  
  static u_char *
  ngx_http_log_body_bytes_sent(ngx_http_request_t *r, u_char *buf,
      ngx_http_log_op_t *op)
  {
      off_t  length;
  
      length = r->connection->sent - r->header_size;
  
      if (length > 0) {
          return ngx_sprintf(buf, "%O", length);
      }
  
      *buf = '0';
  
      return buf + 1;
  }
  
  
  static u_char *
  ngx_http_log_request_length(ngx_http_request_t *r, u_char *buf,
      ngx_http_log_op_t *op)
  {
      return ngx_sprintf(buf, "%O", r->request_length);
  }
  
  
  static ngx_int_t
  ngx_http_log_variable_compile(ngx_conf_t *cf, ngx_http_log_op_t *op,
      ngx_str_t *value, ngx_uint_t json)
  {
      ngx_int_t  index;
  
      index = ngx_http_get_variable_index(cf, value);
      if (index == NGX_ERROR) {
          return NGX_ERROR;
      }
  
      op->len = 0;
  
      if (json) {
          op->getlen = ngx_http_log_json_variable_getlen;
          op->run = ngx_http_log_json_variable;
  
      } else {
          op->getlen = ngx_http_log_variable_getlen;
          op->run = ngx_http_log_variable;
      }
  
      op->data = index;
  
      return NGX_OK;
  }
  
  
  static size_t
  ngx_http_log_variable_getlen(ngx_http_request_t *r, uintptr_t data)
  {
      uintptr_t                   len;
      ngx_http_log_loc_conf_t    *lcf;
      ngx_http_variable_value_t  *value;
  
      value = ngx_http_get_indexed_variable(r, data);
  
      if (value == NULL || value->not_found) {
          return 1;
      }
  
      lcf = ngx_http_get_module_loc_conf(r, ngx_http_log_module);
  
      len = ngx_http_log_escape(lcf, NULL, value->data, value->len);
  
      value->escape = len ? 1 : 0;
  
      return value->len + len * 3;
  }
  
  
  static u_char *
  ngx_http_log_variable(ngx_http_request_t *r, u_char *buf, ngx_http_log_op_t *op)
  {
      ngx_http_log_loc_conf_t    *lcf;
      ngx_http_variable_value_t  *value;
  
      value = ngx_http_get_indexed_variable(r, op->data);
  
      if (value == NULL || value->not_found) {
          *buf = '-';
          return buf + 1;
      }
  
      if (value->escape == 0) {
          return ngx_cpymem(buf, value->data, value->len);
  
      } else {
          lcf = ngx_http_get_module_loc_conf(r, ngx_http_log_module);
          return (u_char *) ngx_http_log_escape(lcf, buf, value->data, value->len);
      }
  }
  
  
  static uintptr_t
  ngx_http_log_escape(ngx_http_log_loc_conf_t *lcf, u_char *dst, u_char *src,
      size_t size)
  {
      ngx_uint_t                   n;
      static u_char                hex[] = "0123456789ABCDEF";
  
      static uint32_t   escape[] = {
          0xffffffff, /* 1111 1111 1111 1111  1111 1111 1111 1111 */
  
                      /* ?>=< ;:98 7654 3210  /.-, +*)( '&%$ #"!  */
          0x00000004, /* 0000 0000 0000 0000  0000 0000 0000 0100 */
  
                      /* _^]\ [ZYX WVUT SRQP  ONML KJIH GFED CBA@ */
          0x10000000, /* 0001 0000 0000 0000  0000 0000 0000 0000 */
  
                      /*  ~}| {zyx wvut srqp  onml kjih gfed cba` */
          0x80000000, /* 1000 0000 0000 0000  0000 0000 0000 0000 */
  
          0xffffffff, /* 1111 1111 1111 1111  1111 1111 1111 1111 */
          0xffffffff, /* 1111 1111 1111 1111  1111 1111 1111 1111 */
          0xffffffff, /* 1111 1111 1111 1111  1111 1111 1111 1111 */
          0xffffffff, /* 1111 1111 1111 1111  1111 1111 1111 1111 */
      };
  
      if (lcf->escape_non_ascii) {
          ngx_memset(&escape[4], 0xff, sizeof(uint32_t) * 4);
  
      } else {
          ngx_memzero(&escape[4], sizeof(uint32_t) * 4);
      }
  
      if (dst == NULL) {
  
          /* find the number of the characters to be escaped */
  
          n = 0;
  
          while (size) {
              if (escape[*src >> 5] & (1U << (*src & 0x1f))) {
                  n++;
              }
              src++;
              size--;
          }
  
          return (uintptr_t) n;
      }
  
      while (size) {
          if (escape[*src >> 5] & (1U << (*src & 0x1f))) {
              *dst++ = '\\';
              *dst++ = 'x';
              *dst++ = hex[*src >> 4];
              *dst++ = hex[*src & 0xf];
              src++;
  
          } else {
              *dst++ = *src++;
          }
          size--;
      }
  
      return (uintptr_t) dst;
  }
  
  
  static size_t
  ngx_http_log_json_variable_getlen(ngx_http_request_t *r, uintptr_t data)
  {
      uintptr_t                   len;
      ngx_http_variable_value_t  *value;
  
      value = ngx_http_get_indexed_variable(r, data);
  
      if (value == NULL || value->not_found) {
          return 0;
      }
  
      len = ngx_escape_json(NULL, value->data, value->len);
  
      value->escape = len ? 1 : 0;
  
      return value->len + len;
  }
  
  
  static u_char *
  ngx_http_log_json_variable(ngx_http_request_t *r, u_char *buf,
      ngx_http_log_op_t *op)
  {
      ngx_http_variable_value_t  *value;
  
      value = ngx_http_get_indexed_variable(r, op->data);
  
      if (value == NULL || value->not_found) {
          return buf;
      }
  
      if (value->escape == 0) {
          return ngx_cpymem(buf, value->data, value->len);
  
      } else {
          return (u_char *) ngx_escape_json(buf, value->data, value->len);
      }
  }
  
  
  static void *
  ngx_http_log_create_main_conf(ngx_conf_t *cf)
  {
      ngx_http_log_main_conf_t  *conf;
  
      ngx_http_log_fmt_t  *fmt;
  
      conf = ngx_pcalloc(cf->pool, sizeof(ngx_http_log_main_conf_t));
      if (conf == NULL) {
          return NULL;
      }
  
      if (ngx_array_init(&conf->formats, cf->pool, 4, sizeof(ngx_http_log_fmt_t))
          != NGX_OK)
      {
          return NULL;
      }
  
      fmt = ngx_array_push(&conf->formats);
      if (fmt == NULL) {
          return NULL;
      }
  
      ngx_str_set(&fmt->name, "combined");
  
      fmt->flushes = NULL;
  
      fmt->ops = ngx_array_create(cf->pool, 16, sizeof(ngx_http_log_op_t));
      if (fmt->ops == NULL) {
          return NULL;
      }
  
      return conf;
  }
  
  
  static void *
  ngx_http_log_create_loc_conf(ngx_conf_t *cf)
  {
      ngx_http_log_loc_conf_t  *conf;
  
      conf = ngx_pcalloc(cf->pool, sizeof(ngx_http_log_loc_conf_t));
      if (conf == NULL) {
          return NULL;
      }
  
      conf->open_file_cache = NGX_CONF_UNSET_PTR;
      conf->escape_non_ascii = NGX_CONF_UNSET;
  
      return conf;
  }
  
  
  static char *
  ngx_http_log_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child)
  {
      ngx_http_log_loc_conf_t *prev = parent;
      ngx_http_log_loc_conf_t *conf = child;
  
      ngx_http_log_t            *log;
      ngx_http_log_fmt_t        *fmt;
      ngx_http_log_main_conf_t  *lmcf;
  
      ngx_conf_merge_value(conf->escape_non_ascii, prev->escape_non_ascii, 1);
  
      if (conf->open_file_cache == NGX_CONF_UNSET_PTR) {
  
          conf->open_file_cache = prev->open_file_cache;
          conf->open_file_cache_valid = prev->open_file_cache_valid;
          conf->open_file_cache_min_uses = prev->open_file_cache_min_uses;
  
          if (conf->open_file_cache == NGX_CONF_UNSET_PTR) {
              conf->open_file_cache = NULL;
          }
      }
  
      if (conf->logs || conf->off) {
          return NGX_CONF_OK;
      }
  
      conf->logs = prev->logs;
      conf->off = prev->off;
  
      if (conf->logs || conf->off) {
          return NGX_CONF_OK;
      }
  
      conf->logs = ngx_array_create(cf->pool, 2, sizeof(ngx_http_log_t));
      if (conf->logs == NULL) {
          return NGX_CONF_ERROR;
      }
  
      log = ngx_array_push(conf->logs);
      if (log == NULL) {
          return NGX_CONF_ERROR;
      }
  
      ngx_memzero(log, sizeof(ngx_http_log_t));
  
      log->file = ngx_conf_open_file(cf->cycle, &ngx_http_access_log);
      if (log->file == NULL) {
          return NGX_CONF_ERROR;
      }
  
      lmcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_log_module);
      fmt = lmcf->formats.elts;
  
      /* the default "combined" format */
      log->format = &fmt[0];
      lmcf->combined_used = 1;
  
      return NGX_CONF_OK;
  }
  
  
  static char *
  ngx_http_log_set_log(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
  {
      ngx_http_log_loc_conf_t *llcf = conf;
  
      ssize_t                            size;
      ngx_int_t                          gzip;
      ngx_uint_t                         i, n;
      ngx_msec_t                         flush;
      ngx_str_t                         *value, name, s;
      ngx_http_log_t                    *log;
      ngx_syslog_peer_t                 *peer;
      ngx_http_log_buf_t                *buffer;
      ngx_http_log_fmt_t                *fmt;
      ngx_http_log_main_conf_t          *lmcf;
      ngx_http_script_compile_t          sc;
      ngx_http_compile_complex_value_t   ccv;
  
      value = cf->args->elts;
  
      if (ngx_strcmp(value[1].data, "off") == 0) {
          llcf->off = 1;
          if (cf->args->nelts == 2) {
              return NGX_CONF_OK;
          }
  
          ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                             "invalid parameter \"%V\"", &value[2]);
          return NGX_CONF_ERROR;
      }
  
      if (llcf->logs == NULL) {
          llcf->logs = ngx_array_create(cf->pool, 2, sizeof(ngx_http_log_t));
          if (llcf->logs == NULL) {
              return NGX_CONF_ERROR;
          }
      }
  
      lmcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_log_module);
  
      log = ngx_array_push(llcf->logs);
      if (log == NULL) {
          return NGX_CONF_ERROR;
      }
  
      ngx_memzero(log, sizeof(ngx_http_log_t));
  
  
      if (ngx_strncmp(value[1].data, "syslog:", 7) == 0) {
  
          peer = ngx_pcalloc(cf->pool, sizeof(ngx_syslog_peer_t));
          if (peer == NULL) {
              return NGX_CONF_ERROR;
          }
  
          if (ngx_syslog_process_conf(cf, peer) != NGX_CONF_OK) {
              return NGX_CONF_ERROR;
          }
  
          log->syslog_peer = peer;
  
          goto process_formats;
      }
  
      n = ngx_http_script_variables_count(&value[1]);
  
      if (n == 0) {
          log->file = ngx_conf_open_file(cf->cycle, &value[1]);
          if (log->file == NULL) {
              return NGX_CONF_ERROR;
          }
  
      } else {
          if (ngx_conf_full_name(cf->cycle, &value[1], 0) != NGX_OK) {
              return NGX_CONF_ERROR;
          }
  
          log->script = ngx_pcalloc(cf->pool, sizeof(ngx_http_log_script_t));
          if (log->script == NULL) {
              return NGX_CONF_ERROR;
          }
  
          ngx_memzero(&sc, sizeof(ngx_http_script_compile_t));
  
          sc.cf = cf;
          sc.source = &value[1];
          sc.lengths = &log->script->lengths;
          sc.values = &log->script->values;
          sc.variables = n;
          sc.complete_lengths = 1;
          sc.complete_values = 1;
  
          if (ngx_http_script_compile(&sc) != NGX_OK) {
              return NGX_CONF_ERROR;
          }
      }
  
  process_formats:
  
      if (cf->args->nelts >= 3) {
          name = value[2];
  
          if (ngx_strcmp(name.data, "combined") == 0) {
              lmcf->combined_used = 1;
          }
  
      } else {
          ngx_str_set(&name, "combined");
          lmcf->combined_used = 1;
      }
  
      fmt = lmcf->formats.elts;
      for (i = 0; i < lmcf->formats.nelts; i++) {
          if (fmt[i].name.len == name.len
              && ngx_strcasecmp(fmt[i].name.data, name.data) == 0)
          {
              log->format = &fmt[i];
              break;
          }
      }
  
      if (log->format == NULL) {
          ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                             "unknown log format \"%V\"", &name);
          return NGX_CONF_ERROR;
      }
  
      size = 0;
      flush = 0;
      gzip = 0;
  
      for (i = 3; i < cf->args->nelts; i++) {
  
          if (ngx_strncmp(value[i].data, "buffer=", 7) == 0) {
              s.len = value[i].len - 7;
              s.data = value[i].data + 7;
  
              size = ngx_parse_size(&s);
  
              if (size == NGX_ERROR || size == 0) {
                  ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                                     "invalid buffer size \"%V\"", &s);
                  return NGX_CONF_ERROR;
              }
  
              continue;
          }
  
          if (ngx_strncmp(value[i].data, "flush=", 6) == 0) {
              s.len = value[i].len - 6;
              s.data = value[i].data + 6;
  
              flush = ngx_parse_time(&s, 0);
  
              if (flush == (ngx_msec_t) NGX_ERROR || flush == 0) {
                  ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                                     "invalid flush time \"%V\"", &s);
                  return NGX_CONF_ERROR;
              }
  
              continue;
          }
  
          if (ngx_strncmp(value[i].data, "gzip", 4) == 0
              && (value[i].len == 4 || value[i].data[4] == '='))
          {
  #if (NGX_ZLIB)
              if (size == 0) {
                  size = 64 * 1024;
              }
  
              if (value[i].len == 4) {
                  gzip = Z_BEST_SPEED;
                  continue;
              }
  
              s.len = value[i].len - 5;
              s.data = value[i].data + 5;
  
              gzip = ngx_atoi(s.data, s.len);
  
              if (gzip < 1 || gzip > 9) {
                  ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                                     "invalid compression level \"%V\"", &s);
                  return NGX_CONF_ERROR;
              }
  
              continue;
  
  #else
              ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                                 "nginx was built without zlib support");
              return NGX_CONF_ERROR;
  #endif
          }
  
          if (ngx_strncmp(value[i].data, "if=", 3) == 0) {
              s.len = value[i].len - 3;
              s.data = value[i].data + 3;
  
              ngx_memzero(&ccv, sizeof(ngx_http_compile_complex_value_t));
  
              ccv.cf = cf;
              ccv.value = &s;
              ccv.complex_value = ngx_palloc(cf->pool,
                                             sizeof(ngx_http_complex_value_t));
              if (ccv.complex_value == NULL) {
                  return NGX_CONF_ERROR;
              }
  
              if (ngx_http_compile_complex_value(&ccv) != NGX_OK) {
                  return NGX_CONF_ERROR;
              }
  
              log->filter = ccv.complex_value;
  
              continue;
          }
  
          ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                             "invalid parameter \"%V\"", &value[i]);
          return NGX_CONF_ERROR;
      }
  
      if (flush && size == 0) {
          ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                             "no buffer is defined for access_log \"%V\"",
                             &value[1]);
          return NGX_CONF_ERROR;
      }
  
      if (size) {
  
          if (log->script) {
              ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                                 "buffered logs cannot have variables in name");
              return NGX_CONF_ERROR;
          }
  
          if (log->syslog_peer) {
              ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                                 "logs to syslog cannot be buffered");
              return NGX_CONF_ERROR;
          }
  
          if (log->file->data) {
              buffer = log->file->data;
  
              if (buffer->last - buffer->start != size
                  || buffer->flush != flush
                  || buffer->gzip != gzip)
              {
                  ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                                     "access_log \"%V\" already defined "
                                     "with conflicting parameters",
                                     &value[1]);
                  return NGX_CONF_ERROR;
              }
  
              return NGX_CONF_OK;
          }
  
          buffer = ngx_pcalloc(cf->pool, sizeof(ngx_http_log_buf_t));
          if (buffer == NULL) {
              return NGX_CONF_ERROR;
          }
  
          buffer->start = ngx_pnalloc(cf->pool, size);
          if (buffer->start == NULL) {
              return NGX_CONF_ERROR;
          }
  
          buffer->pos = buffer->start;
          buffer->last = buffer->start + size;
  
          if (flush) {
              buffer->event = ngx_pcalloc(cf->pool, sizeof(ngx_event_t));
              if (buffer->event == NULL) {
                  return NGX_CONF_ERROR;
              }
  
              buffer->event->data = log->file;
              buffer->event->handler = ngx_http_log_flush_handler;
              buffer->event->log = &cf->cycle->new_log;
              buffer->event->cancelable = 1;
  
              buffer->flush = flush;
          }
  
          buffer->gzip = gzip;
  
          log->file->flush = ngx_http_log_flush;
          log->file->data = buffer;
      }
  
      return NGX_CONF_OK;
  }
  
  
  static char *
  ngx_http_log_set_format(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
  {
      ngx_http_log_main_conf_t *lmcf = conf;
  
      ngx_str_t           *value;
      ngx_uint_t           i;
      ngx_http_log_fmt_t  *fmt;
  
      value = cf->args->elts;
  
      fmt = lmcf->formats.elts;
      for (i = 0; i < lmcf->formats.nelts; i++) {
          if (fmt[i].name.len == value[1].len
              && ngx_strcmp(fmt[i].name.data, value[1].data) == 0)
          {
              ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                                 "duplicate \"log_format\" name \"%V\"",
                                 &value[1]);
              return NGX_CONF_ERROR;
          }
      }
  
      fmt = ngx_array_push(&lmcf->formats);
      if (fmt == NULL) {
          return NGX_CONF_ERROR;
      }
  
      fmt->name = value[1];
  
      fmt->flushes = ngx_array_create(cf->pool, 4, sizeof(ngx_int_t));
      if (fmt->flushes == NULL) {
          return NGX_CONF_ERROR;
      }
  
      fmt->ops = ngx_array_create(cf->pool, 16, sizeof(ngx_http_log_op_t));
      if (fmt->ops == NULL) {
          return NGX_CONF_ERROR;
      }
  
      return ngx_http_log_compile_format(cf, fmt->flushes, fmt->ops, cf->args, 2);
  }
  
  
  static char *
  ngx_http_log_compile_format(ngx_conf_t *cf, ngx_array_t *flushes,
      ngx_array_t *ops, ngx_array_t *args, ngx_uint_t s)
  {
      u_char              *data, *p, ch;
      size_t               i, len;
      ngx_str_t           *value, var;
      ngx_int_t           *flush;
      ngx_uint_t           bracket, json;
      ngx_http_log_op_t   *op;
      ngx_http_log_var_t  *v;
  
      json = 0;
      value = args->elts;
  
      if (s < args->nelts && ngx_strncmp(value[s].data, "escape=", 7) == 0) {
          data = value[s].data + 7;
  
          if (ngx_strcmp(data, "json") == 0) {
              json = 1;
  
          } else if (ngx_strcmp(data, "default") != 0) {
              ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                                 "unknown log format escaping \"%s\"", data);
              return NGX_CONF_ERROR;
          }
  
          s++;
      }
  
      for ( /* void */ ; s < args->nelts; s++) {
  
          i = 0;
  
          while (i < value[s].len) {
  
              op = ngx_array_push(ops);
              if (op == NULL) {
                  return NGX_CONF_ERROR;
              }
  
              data = &value[s].data[i];
  
              if (value[s].data[i] == '$') {
  
                  if (++i == value[s].len) {
                      goto invalid;
                  }
  
                  if (value[s].data[i] == '{') {
                      bracket = 1;
  
                      if (++i == value[s].len) {
                          goto invalid;
                      }
  
                      var.data = &value[s].data[i];
  
                  } else {
                      bracket = 0;
                      var.data = &value[s].data[i];
                  }
  
                  for (var.len = 0; i < value[s].len; i++, var.len++) {
                      ch = value[s].data[i];
  
                      if (ch == '}' && bracket) {
                          i++;
                          bracket = 0;
                          break;
                      }
  
                      if ((ch >= 'A' && ch <= 'Z')
                          || (ch >= 'a' && ch <= 'z')
                          || (ch >= '0' && ch <= '9')
                          || ch == '_')
                      {
                          continue;
                      }
  
                      break;
                  }
  
                  if (bracket) {
                      ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                                         "the closing bracket in \"%V\" "
                                         "variable is missing", &var);
                      return NGX_CONF_ERROR;
                  }
  
                  if (var.len == 0) {
                      goto invalid;
                  }
  
                  for (v = ngx_http_log_vars; v->name.len; v++) {
  
                      if (v->name.len == var.len
                          && ngx_strncmp(v->name.data, var.data, var.len) == 0)
                      {
                          op->len = v->len;
                          op->getlen = NULL;
                          op->run = v->run;
                          op->data = 0;
  
                          goto found;
                      }
                  }
  
                  if (ngx_http_log_variable_compile(cf, op, &var, json)
                      != NGX_OK)
                  {
                      return NGX_CONF_ERROR;
                  }
  
                  if (flushes) {
  
                      flush = ngx_array_push(flushes);
                      if (flush == NULL) {
                          return NGX_CONF_ERROR;
                      }
  
                      *flush = op->data; /* variable index */
                  }
  
              found:
  
                  continue;
              }
  
              i++;
  
              while (i < value[s].len && value[s].data[i] != '$') {
                  i++;
              }
  
              len = &value[s].data[i] - data;
  
              if (len) {
  
                  op->len = len;
                  op->getlen = NULL;
  
                  if (len <= sizeof(uintptr_t)) {
                      op->run = ngx_http_log_copy_short;
                      op->data = 0;
  
                      while (len--) {
                          op->data <<= 8;
                          op->data |= data[len];
                      }
  
                  } else {
                      op->run = ngx_http_log_copy_long;
  
                      p = ngx_pnalloc(cf->pool, len);
                      if (p == NULL) {
                          return NGX_CONF_ERROR;
                      }
  
                      ngx_memcpy(p, data, len);
                      op->data = (uintptr_t) p;
                  }
              }
          }
      }
  
      return NGX_CONF_OK;
  
  invalid:
  
      ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "invalid parameter \"%s\"", data);
  
      return NGX_CONF_ERROR;
  }
  
  
  static char *
  ngx_http_log_open_file_cache(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
  {
      ngx_http_log_loc_conf_t *llcf = conf;
  
      time_t       inactive, valid;
      ngx_str_t   *value, s;
      ngx_int_t    max, min_uses;
      ngx_uint_t   i;
  
      if (llcf->open_file_cache != NGX_CONF_UNSET_PTR) {
          return "is duplicate";
      }
  
      value = cf->args->elts;
  
      max = 0;
      inactive = 10;
      valid = 60;
      min_uses = 1;
  
      for (i = 1; i < cf->args->nelts; i++) {
  
          if (ngx_strncmp(value[i].data, "max=", 4) == 0) {
  
              max = ngx_atoi(value[i].data + 4, value[i].len - 4);
              if (max == NGX_ERROR) {
                  goto failed;
              }
  
              continue;
          }
  
          if (ngx_strncmp(value[i].data, "inactive=", 9) == 0) {
  
              s.len = value[i].len - 9;
              s.data = value[i].data + 9;
  
              inactive = ngx_parse_time(&s, 1);
              if (inactive == (time_t) NGX_ERROR) {
                  goto failed;
              }
  
              continue;
          }
  
          if (ngx_strncmp(value[i].data, "min_uses=", 9) == 0) {
  
              min_uses = ngx_atoi(value[i].data + 9, value[i].len - 9);
              if (min_uses == NGX_ERROR) {
                  goto failed;
              }
  
              continue;
          }
  
          if (ngx_strncmp(value[i].data, "valid=", 6) == 0) {
  
              s.len = value[i].len - 6;
              s.data = value[i].data + 6;
  
              valid = ngx_parse_time(&s, 1);
              if (valid == (time_t) NGX_ERROR) {
                  goto failed;
              }
  
              continue;
          }
  
          if (ngx_strcmp(value[i].data, "off") == 0) {
  
              llcf->open_file_cache = NULL;
  
              continue;
          }
  
      failed:
  
          ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                             "invalid \"open_log_file_cache\" parameter \"%V\"",
                             &value[i]);
          return NGX_CONF_ERROR;
      }
  
      if (llcf->open_file_cache == NULL) {
          return NGX_CONF_OK;
      }
  
      if (max == 0) {
          ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                          "\"open_log_file_cache\" must have \"max\" parameter");
          return NGX_CONF_ERROR;
      }
  
      llcf->open_file_cache = ngx_open_file_cache_init(cf->pool, max, inactive);
  
      if (llcf->open_file_cache) {
  
          llcf->open_file_cache_valid = valid;
          llcf->open_file_cache_min_uses = min_uses;
  
          return NGX_CONF_OK;
      }
  
      return NGX_CONF_ERROR;
  }
  
  
  static ngx_int_t
  ngx_http_log_init(ngx_conf_t *cf)
  {
      ngx_str_t                  *value;
      ngx_array_t                 a;
      ngx_http_handler_pt        *h;
      ngx_http_log_fmt_t         *fmt;
      ngx_http_log_main_conf_t   *lmcf;
      ngx_http_core_main_conf_t  *cmcf;
  
      lmcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_log_module);
  
      if (lmcf->combined_used) {
          if (ngx_array_init(&a, cf->pool, 1, sizeof(ngx_str_t)) != NGX_OK) {
              return NGX_ERROR;
          }
  
          value = ngx_array_push(&a);
          if (value == NULL) {
              return NGX_ERROR;
          }
  
          *value = ngx_http_combined_fmt;
          fmt = lmcf->formats.elts;
  
          if (ngx_http_log_compile_format(cf, NULL, fmt->ops, &a, 0)
              != NGX_CONF_OK)
          {
              return NGX_ERROR;
          }
      }
  
      cmcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_core_module);
  
      h = ngx_array_push(&cmcf->phases[NGX_HTTP_LOG_PHASE].handlers);
      if (h == NULL) {
          return NGX_ERROR;
      }
  
      *h = ngx_http_log_handler;
  
      return NGX_OK;
  }
  