text: /* Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to You under the Apache License, Version 2.0
   * (the "License"); you may not use this file except in compliance with
   * the License.  You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   * 
   */
  
  #include <stdint.h>
  #include <ap_config.h>
  #include "ap_mpm.h"
  #include <http_core.h>
  #include <http_log.h>
  #include <apr_version.h>
  #include <apr_pools.h>
  #include <apr_strings.h>
  #include "unixd.h"
  #include "scoreboard.h"
  #include "mpm_common.h"
  
  #include "systemd/sd-daemon.h"
  
  #if APR_HAVE_UNISTD_H
  #include <unistd.h>
  #endif
  
  #define KBYTE 1024
  
  static pid_t pid;	/* PID of the main httpd instance */
  static int server_limit, thread_limit, threads_per_child, max_servers;
  static time_t last_update_time;
  static unsigned long last_update_access;
  static unsigned long last_update_kbytes;
  
  static int systemd_pre_mpm(apr_pool_t *p, ap_scoreboard_e sb_type)
  {
      int rv;
      last_update_time = time(0);
  
      ap_mpm_query(AP_MPMQ_HARD_LIMIT_THREADS, &thread_limit);
      ap_mpm_query(AP_MPMQ_HARD_LIMIT_DAEMONS, &server_limit);
      ap_mpm_query(AP_MPMQ_MAX_THREADS, &threads_per_child);
      /* work around buggy MPMs */
      if (threads_per_child == 0)
          threads_per_child = 1;
      ap_mpm_query(AP_MPMQ_MAX_DAEMONS, &max_servers);
  
      pid = getpid();
      
      rv = sd_notifyf(0, "READY=1\n"
                      "STATUS=Processing requests...\n"
                      "MAINPID=%lu",
                      (unsigned long) pid);
      if (rv < 0) {
          ap_log_perror(APLOG_MARK, APLOG_ERR, 0, p, 
                       "sd_notifyf returned an error %d", rv);
      }
  
      return OK;
  }
  
  static int systemd_monitor(apr_pool_t *p, server_rec *s)
  {
      int i, j, res, rv;
      process_score *ps_record;
      worker_score *ws_record;
      unsigned long access = 0;
      unsigned long bytes = 0;
      unsigned long kbytes = 0;
      char bps[5];
      time_t now = time(0);
      time_t elapsed = now - last_update_time;
  
      for (i = 0; i < server_limit; ++i) {
          ps_record = ap_get_scoreboard_process(i);
          for (j = 0; j < thread_limit; ++j) {
              ws_record = ap_get_scoreboard_worker_from_indexes(i, j);
              if (ap_extended_status && !ps_record->quiescing && ps_record->pid) {
                  res = ws_record->status;
                  if (ws_record->access_count != 0 || 
                      (res != SERVER_READY && res != SERVER_DEAD)) {
                      access += ws_record->access_count;
                      bytes += ws_record->bytes_served;
                      if (bytes >= KBYTE) {
                          kbytes += (bytes >> 10);
                          bytes = bytes & 0x3ff;
                      }
                  }
              }
          }
      }
  
      apr_strfsize((unsigned long)(KBYTE *(float) (kbytes - last_update_kbytes)
                                   / (float) elapsed), bps);
  
      rv = sd_notifyf(0, "READY=1\n"
                      "STATUS=Total requests: %lu; Current requests/sec: %.3g; "
                      "Current traffic: %sB/sec\n", access,
                      ((float)access - last_update_access) / (float) elapsed, bps);
      if (rv < 0) {
          ap_log_error(APLOG_MARK, APLOG_ERR, 0, s, APLOGNO(00000)
                       "sd_notifyf returned an error %d", rv);
      }
  
      last_update_access = access;
      last_update_kbytes = kbytes;
      last_update_time = now;
  
      return DECLINED;
  }
  
  static void systemd_register_hooks(apr_pool_t *p)
  {
      /* We know the PID in this hook ... */
      ap_hook_pre_mpm(systemd_pre_mpm, NULL, NULL, APR_HOOK_LAST);
      /* Used to update httpd's status line using sd_notifyf */
      ap_hook_monitor(systemd_monitor, NULL, NULL, APR_HOOK_MIDDLE);
  }
  
  module AP_MODULE_DECLARE_DATA systemd_module =
  {
      STANDARD20_MODULE_STUFF,
      NULL,
      NULL,
      NULL,
      NULL,
      NULL,
      systemd_register_hooks,
  };
  