/*

Instructions :
==============

   Install :  apxs -i -a -c mod_load.c
   Configure : MaxLoad apache directive (default is 25)


Apache 2.0 version :
--------------------

   Copyright (C) 2005
   Planet-Work SARL
   http://www.planet-work.fr/
   Frederic VANNIERE - f.vanniere@planet-work.com

Original Apache 1.3 version :
-----------------------------

   Copyright (C) 2000,2001,2002,2003
   SedNove Inc.
   439 OAK
   St-Lambert, QC, Canada
   All rights reserved.
   Pierre Laplante
   Wed Nov 20 15:53:45 2002
   Pierre.Laplante@sednove.com

*/

#include "httpd.h"
#include "http_config.h"
#include "http_core.h"
#include "http_log.h"
#include "http_protocol.h"
#include "http_request.h"
#include "http_main.h"
#include "util_script.h"
#include "util_md5.h"
#include "ap_config.h"
#include "unistd.h"

/*#define DEBUGLVL 9*/

#ifdef DEBUGLVL
#define DEBUG(lvl,x...) if (lvl<DEBUGLVL) fprintf(stderr, x);
#else
#define DEBUG(lvl,x...)
#endif

module AP_MODULE_DECLARE_DATA load_module;

typedef struct {
  int max_load;
} load_handler_config;

static void *
create_config(apr_pool_t *p, server_rec *s) {
  load_handler_config *c;

  DEBUG(5, "create_config\n");

  c = (load_handler_config *) apr_pcalloc(p, sizeof(load_handler_config));
  c -> max_load = 25;

  DEBUG(5, "create_config c=%x.\n", c);
  return (void *) c;
}



static const char *
my_handler(cmd_parms *parms, void *mconfig, char *to) {
  load_handler_config *c;

  DEBUG(5, "my_handler, to=%s, mconfig=%x, parms=%x/%x\n", to, mconfig, parms, parms);
  c = (load_handler_config *) ap_get_module_config(parms->server->module_config,
						   &load_module);

  DEBUG(5, "c=%x\n", c);
  c -> max_load = atoi(to);
  return NULL;
}


static const command_rec load_cmds[] =
{
  AP_INIT_TAKE1("MaxLoad",my_handler,(void*) 0,RSRC_CONF,"Set max Loadavg." ),
  {NULL}
};


static int load_handler(request_rec *r) {
  int fd;
  float la;
  char buf[1024];
  load_handler_config *c;

  DEBUG(5, "load_handler\n");

  c = (load_handler_config *) ap_get_module_config(r->server->module_config,
						   &load_module);
  DEBUG(5, "c=%x\n", c);
  DEBUG(5, "load = %d \n", c -> max_load);
  fd = open("/proc/loadavg", O_RDONLY);
  if (read(fd, buf, 1024) <=0) {
    //ap_log_reason("Can't open /proc/loadavg", "/proc/loadavg", r);
    ap_log_error(APLOG_MARK, APLOG_ERR,0,NULL, "Can't open /proc/loadavg");
    return DECLINED;
  } else {
    sscanf(buf, "%f", &la);
    if (la > c -> max_load) {
      ap_log_error(APLOG_MARK, APLOG_ERR,0,NULL,
		   "load is too high %f/%d ...\n", la, c->max_load);
      return HTTP_SERVICE_UNAVAILABLE;
    }
  }
  close(fd);

  return DECLINED;
}

static void
load_register_hooks (apr_pool_t * p)
{
        ap_hook_access_checker(load_handler,NULL,NULL,APR_HOOK_FIRST);
}

module AP_MODULE_DECLARE_DATA load_module =
{
    STANDARD20_MODULE_STUFF,
    NULL,  /* per-directory config creator       */
    NULL,   /* dir config merger                  */
    create_config,               /* server config creator              */
    NULL,               /* server config merger               */
    load_cmds,         /* command table                      */
    load_register_hooks
};