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.
   */
  
  /* Load balancer module for Apache proxy */
  
  #include "mod_proxy.h"
  #include "scoreboard.h"
  #include "ap_mpm.h"
  #include "apr_version.h"
  #include "ap_hooks.h"
  #include "apr_date.h"
  
  static const char *balancer_mutex_type = "proxy-balancer-shm";
  ap_slotmem_provider_t *storage = NULL;
  
  module AP_MODULE_DECLARE_DATA proxy_balancer_module;
  
  static int (*ap_proxy_retry_worker_fn)(const char *proxy_function,
          proxy_worker *worker, server_rec *s) = NULL;
  
  /*
   * Register our mutex type before the config is read so we
   * can adjust the mutex settings using the Mutex directive.
   */
  static int balancer_pre_config(apr_pool_t *pconf, apr_pool_t *plog,
                                 apr_pool_t *ptemp)
  {
  
      apr_status_t rv;
  
      rv = ap_mutex_register(pconf, balancer_mutex_type, NULL,
                                 APR_LOCK_DEFAULT, 0);
      if (rv != APR_SUCCESS) {
          return rv;
      }
  
      return OK;
  }
  
  #if 0
  extern void proxy_update_members(proxy_balancer **balancer, request_rec *r,
                                   proxy_server_conf *conf);
  #endif
  
  static int proxy_balancer_canon(request_rec *r, char *url)
  {
      char *host, *path;
      char *search = NULL;
      const char *err;
      apr_port_t port = 0;
  
      /* TODO: offset of BALANCER_PREFIX ?? */
      if (strncasecmp(url, "balancer:", 9) == 0) {
          url += 9;
      }
      else {
          return DECLINED;
      }
  
      ap_log_rerror(APLOG_MARK, APLOG_TRACE1, 0, r, "canonicalising URL %s", url);
  
      /* do syntatic check.
       * We break the URL into host, port, path, search
       */
      err = ap_proxy_canon_netloc(r->pool, &url, NULL, NULL, &host, &port);
      if (err) {
          ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, APLOGNO(01157)
                        "error parsing URL %s: %s",
                        url, err);
          return HTTP_BAD_REQUEST;
      }
      /*
       * now parse path/search args, according to rfc1738:
       * process the path. With proxy-noncanon set (by
       * mod_proxy) we use the raw, unparsed uri
       */
      if (apr_table_get(r->notes, "proxy-nocanon")) {
          path = url;   /* this is the raw path */
      }
      else {
          path = ap_proxy_canonenc(r->pool, url, strlen(url), enc_path, 0,
                                   r->proxyreq);
          search = r->args;
      }
      if (path == NULL)
          return HTTP_BAD_REQUEST;
  
      r->filename = apr_pstrcat(r->pool, "proxy:", BALANCER_PREFIX, host,
              "/", path, (search) ? "?" : "", (search) ? search : "", NULL);
  
      r->path_info = apr_pstrcat(r->pool, "/", path, NULL);
  
      return OK;
  }
  
  static void init_balancer_members(apr_pool_t *p, server_rec *s,
                                   proxy_balancer *balancer)
  {
      int i;
      proxy_worker **workers;
  
      workers = (proxy_worker **)balancer->workers->elts;
  
      for (i = 0; i < balancer->workers->nelts; i++) {
          int worker_is_initialized;
          proxy_worker *worker = *workers;
          ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(01158)
                       "Looking at %s -> %s initialized?", balancer->s->name, worker->s->name);
          worker_is_initialized = PROXY_WORKER_IS_INITIALIZED(worker);
          if (!worker_is_initialized) {
              ap_proxy_initialize_worker(worker, s, p);
          }
          ++workers;
      }
  
      /* Set default number of attempts to the number of
       * workers.
       */
      if (!balancer->s->max_attempts_set && balancer->workers->nelts > 1) {
          balancer->s->max_attempts = balancer->workers->nelts - 1;
          balancer->s->max_attempts_set = 1;
      }
  }
  
  /* Retrieve the parameter with the given name
   * Something like 'JSESSIONID=12345...N'
   */
  static char *get_path_param(apr_pool_t *pool, char *url,
                              const char *name, int scolon_sep)
  {
      char *path = NULL;
      char *pathdelims = "?&";
  
      if (scolon_sep) {
          pathdelims = ";?&";
      }
      for (path = strstr(url, name); path; path = strstr(path + 1, name)) {
          path += strlen(name);
          if (*path == '=') {
              /*
               * Session path was found, get its value
               */
              ++path;
              if (*path) {
                  char *q;
                  path = apr_strtok(apr_pstrdup(pool, path), pathdelims, &q);
                  return path;
              }
          }
      }
      return NULL;
  }
  
  static char *get_cookie_param(request_rec *r, const char *name)
  {
      const char *cookies;
      const char *start_cookie;
  
      if ((cookies = apr_table_get(r->headers_in, "Cookie"))) {
          for (start_cookie = ap_strstr_c(cookies, name); start_cookie;
               start_cookie = ap_strstr_c(start_cookie + 1, name)) {
              if (start_cookie == cookies ||
                  start_cookie[-1] == ';' ||
                  start_cookie[-1] == ',' ||
                  isspace(start_cookie[-1])) {
  
                  start_cookie += strlen(name);
                  while(*start_cookie && isspace(*start_cookie))
                      ++start_cookie;
                  if (*start_cookie++ == '=' && *start_cookie) {
                      /*
                       * Session cookie was found, get its value
                       */
                      char *end_cookie, *cookie;
                      cookie = apr_pstrdup(r->pool, start_cookie);
                      if ((end_cookie = strchr(cookie, ';')) != NULL)
                          *end_cookie = '\0';
                      if((end_cookie = strchr(cookie, ',')) != NULL)
                          *end_cookie = '\0';
                      return cookie;
                  }
              }
          }
      }
      return NULL;
  }
  
  /* Find the worker that has the 'route' defined
   */
  static proxy_worker *find_route_worker(proxy_balancer *balancer,
                                         const char *route, request_rec *r)
  {
      int i;
      int checking_standby;
      int checked_standby;
  
      proxy_worker **workers;
  
      checking_standby = checked_standby = 0;
      while (!checked_standby) {
          workers = (proxy_worker **)balancer->workers->elts;
          for (i = 0; i < balancer->workers->nelts; i++, workers++) {
              proxy_worker *worker = *workers;
              if ( (checking_standby ? !PROXY_WORKER_IS_STANDBY(worker) : PROXY_WORKER_IS_STANDBY(worker)) )
                  continue;
              if (*(worker->s->route) && strcmp(worker->s->route, route) == 0) {
                  if (PROXY_WORKER_IS_USABLE(worker)) {
                      return worker;
                  } else {
                      /*
                       * If the worker is in error state run
                       * retry on that worker. It will be marked as
                       * operational if the retry timeout is elapsed.
                       * The worker might still be unusable, but we try
                       * anyway.
                       */
                      ap_proxy_retry_worker_fn("BALANCER", worker, r->server);
                      if (PROXY_WORKER_IS_USABLE(worker)) {
                              return worker;
                      } else {
                          /*
                           * We have a worker that is unusable.
                           * It can be in error or disabled, but in case
                           * it has a redirection set use that redirection worker.
                           * This enables to safely remove the member from the
                           * balancer. Of course you will need some kind of
                           * session replication between those two remote.
                           */
                          if (*worker->s->redirect) {
                              proxy_worker *rworker = NULL;
                              rworker = find_route_worker(balancer, worker->s->redirect, r);
                              /* Check if the redirect worker is usable */
                              if (rworker && !PROXY_WORKER_IS_USABLE(rworker)) {
                                  /*
                                   * If the worker is in error state run
                                   * retry on that worker. It will be marked as
                                   * operational if the retry timeout is elapsed.
                                   * The worker might still be unusable, but we try
                                   * anyway.
                                   */
                                  ap_proxy_retry_worker_fn("BALANCER", rworker, r->server);
                              }
                              if (rworker && PROXY_WORKER_IS_USABLE(rworker))
                                  return rworker;
                          }
                      }
                  }
              }
          }
          checked_standby = checking_standby++;
      }
      return NULL;
  }
  
  static proxy_worker *find_session_route(proxy_balancer *balancer,
                                          request_rec *r,
                                          char **route,
                                          const char **sticky_used,
                                          char **url)
  {
      proxy_worker *worker = NULL;
  
      if (!*balancer->s->sticky)
          return NULL;
      /* Try to find the sticky route inside url */
      *route = get_path_param(r->pool, *url, balancer->s->sticky_path, balancer->s->scolonsep);
      if (*route) {
          ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(01159)
                       "Found value %s for stickysession %s",
                       *route, balancer->s->sticky_path);
          *sticky_used =  balancer->s->sticky_path;
      }
      else {
          *route = get_cookie_param(r, balancer->s->sticky);
          if (*route) {
              *sticky_used =  balancer->s->sticky;
              ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(01160)
                           "Found value %s for stickysession %s",
                           *route, balancer->s->sticky);
          }
      }
      /*
       * If we found a value for stickysession, find the first '.' (or whatever
       * sticky_separator is set to) within. Everything after '.' (if present)
       * is our route. 
       */
      if ((*route) && (balancer->s->sticky_separator != 0) && ((*route = strchr(*route, balancer->s->sticky_separator)) != NULL ))
          (*route)++;
      if ((*route) && (**route)) {
          ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(01161) "Found route %s", *route);
          /* We have a route in path or in cookie
           * Find the worker that has this route defined.
           */
          worker = find_route_worker(balancer, *route, r);
          if (worker && strcmp(*route, worker->s->route)) {
              /*
               * Notice that the route of the worker chosen is different from
               * the route supplied by the client.
               */
              apr_table_setn(r->subprocess_env, "BALANCER_ROUTE_CHANGED", "1");
              ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(01162)
                            "Route changed from %s to %s",
                            *route, worker->s->route);
          }
          return worker;
      }
      else
          return NULL;
  }
  
  static proxy_worker *find_best_worker(proxy_balancer *balancer,
                                        request_rec *r)
  {
      proxy_worker *candidate = NULL;
      apr_status_t rv;
  
      if ((rv = PROXY_THREAD_LOCK(balancer)) != APR_SUCCESS) {
          ap_log_rerror(APLOG_MARK, APLOG_ERR, rv, r, APLOGNO(01163)
                        "%s: Lock failed for find_best_worker()",
                        balancer->s->name);
          return NULL;
      }
  
      candidate = (*balancer->lbmethod->finder)(balancer, r);
  
      if (candidate)
          candidate->s->elected++;
  
      if ((rv = PROXY_THREAD_UNLOCK(balancer)) != APR_SUCCESS) {
          ap_log_rerror(APLOG_MARK, APLOG_ERR, rv, r, APLOGNO(01164)
                        "%s: Unlock failed for find_best_worker()",
                        balancer->s->name);
      }
  
      if (candidate == NULL) {
          /* All the workers are in error state or disabled.
           * If the balancer has a timeout sleep for a while
           * and try again to find the worker. The chances are
           * that some other thread will release a connection.
           * By default the timeout is not set, and the server
           * returns SERVER_BUSY.
           */
          if (balancer->s->timeout) {
              /* XXX: This can perhaps be build using some
               * smarter mechanism, like tread_cond.
               * But since the statuses can came from
               * different childs, use the provided algo.
               */
              apr_interval_time_t timeout = balancer->s->timeout;
              apr_interval_time_t step, tval = 0;
              /* Set the timeout to 0 so that we don't
               * end in infinite loop
               */
              balancer->s->timeout = 0;
              step = timeout / 100;
              while (tval < timeout) {
                  apr_sleep(step);
                  /* Try again */
                  if ((candidate = find_best_worker(balancer, r)))
                      break;
                  tval += step;
              }
              /* restore the timeout */
              balancer->s->timeout = timeout;
          }
      }
  
      return candidate;
  
  }
  
  static int rewrite_url(request_rec *r, proxy_worker *worker,
                          char **url)
  {
      const char *scheme = strstr(*url, "://");
      const char *path = NULL;
  
      if (scheme)
          path = ap_strchr_c(scheme + 3, '/');
  
      /* we break the URL into host, port, uri */
      if (!worker) {
          return ap_proxyerror(r, HTTP_BAD_REQUEST, apr_pstrcat(r->pool,
                               "missing worker. URI cannot be parsed: ", *url,
                               NULL));
      }
  
      *url = apr_pstrcat(r->pool, worker->s->name, path, NULL);
  
      return OK;
  }
  
  static void force_recovery(proxy_balancer *balancer, server_rec *s)
  {
      int i;
      int ok = 0;
      proxy_worker **worker;
  
      worker = (proxy_worker **)balancer->workers->elts;
      for (i = 0; i < balancer->workers->nelts; i++, worker++) {
          if (!((*worker)->s->status & PROXY_WORKER_IN_ERROR)) {
              ok = 1;
              break;
          }
          else {
              /* Try if we can recover */
              ap_proxy_retry_worker_fn("BALANCER", *worker, s);
              if (!((*worker)->s->status & PROXY_WORKER_IN_ERROR)) {
                  ok = 1;
                  break;
              }
          }
      }
      if (!ok && balancer->s->forcerecovery) {
          /* If all workers are in error state force the recovery.
           */
          worker = (proxy_worker **)balancer->workers->elts;
          for (i = 0; i < balancer->workers->nelts; i++, worker++) {
              ++(*worker)->s->retries;
              (*worker)->s->status &= ~PROXY_WORKER_IN_ERROR;
              ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(01165)
                           "%s: Forcing recovery for worker (%s)",
                           balancer->s->name, (*worker)->s->hostname);
          }
      }
  }
  
  static apr_status_t decrement_busy_count(void *worker_)
  {
      proxy_worker *worker = worker_;
      
      if (worker->s->busy) {
          worker->s->busy--;
      }
  
      return APR_SUCCESS;
  }
  
  static int proxy_balancer_pre_request(proxy_worker **worker,
                                        proxy_balancer **balancer,
                                        request_rec *r,
                                        proxy_server_conf *conf, char **url)
  {
      int access_status;
      proxy_worker *runtime;
      char *route = NULL;
      const char *sticky = NULL;
      apr_status_t rv;
  
      *worker = NULL;
      /* Step 1: check if the url is for us
       * The url we can handle starts with 'balancer://'
       * If balancer is already provided skip the search
       * for balancer, because this is failover attempt.
       */
      if (!*balancer &&
          !(*balancer = ap_proxy_get_balancer(r->pool, conf, *url, 1)))
          return DECLINED;
  
      /* Step 2: Lock the LoadBalancer
       * XXX: perhaps we need the process lock here
       */
      if ((rv = PROXY_THREAD_LOCK(*balancer)) != APR_SUCCESS) {
          ap_log_rerror(APLOG_MARK, APLOG_ERR, rv, r, APLOGNO(01166)
                        "%s: Lock failed for pre_request", (*balancer)->s->name);
          return DECLINED;
      }
  
      /* Step 3: force recovery */
      force_recovery(*balancer, r->server);
  
      /* Step 3.5: Update member list for the balancer */
      /* TODO: Implement as provider! */
      ap_proxy_sync_balancer(*balancer, r->server, conf);
  
      /* Step 4: find the session route */
      runtime = find_session_route(*balancer, r, &route, &sticky, url);
      if (runtime) {
          if ((*balancer)->lbmethod && (*balancer)->lbmethod->updatelbstatus) {
              /* Call the LB implementation */
              (*balancer)->lbmethod->updatelbstatus(*balancer, runtime, r->server);
          }
          else { /* Use the default one */
              int i, total_factor = 0;
              proxy_worker **workers;
              /* We have a sticky load balancer
               * Update the workers status
               * so that even session routes get
               * into account.
               */
              workers = (proxy_worker **)(*balancer)->workers->elts;
              for (i = 0; i < (*balancer)->workers->nelts; i++) {
                  /* Take into calculation only the workers that are
                   * not in error state or not disabled.
                   */
                  if (PROXY_WORKER_IS_USABLE(*workers)) {
                      (*workers)->s->lbstatus += (*workers)->s->lbfactor;
                      total_factor += (*workers)->s->lbfactor;
                  }
                  workers++;
              }
              runtime->s->lbstatus -= total_factor;
          }
          runtime->s->elected++;
  
          *worker = runtime;
      }
      else if (route && (*balancer)->s->sticky_force) {
          int i, member_of = 0;
          proxy_worker **workers;
          /*
           * We have a route provided that doesn't match the
           * balancer name. See if the provider route is the
           * member of the same balancer in which case return 503
           */
          workers = (proxy_worker **)(*balancer)->workers->elts;
          for (i = 0; i < (*balancer)->workers->nelts; i++) {
              if (*((*workers)->s->route) && strcmp((*workers)->s->route, route) == 0) {
                  member_of = 1;
                  break;
              }
              workers++;
          }
          if (member_of) {
              ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, APLOGNO(01167)
                            "%s: All workers are in error state for route (%s)",
                            (*balancer)->s->name, route);
              if ((rv = PROXY_THREAD_UNLOCK(*balancer)) != APR_SUCCESS) {
                  ap_log_rerror(APLOG_MARK, APLOG_ERR, rv, r, APLOGNO(01168)
                                "%s: Unlock failed for pre_request",
                                (*balancer)->s->name);
              }
              return HTTP_SERVICE_UNAVAILABLE;
          }
      }
  
      if ((rv = PROXY_THREAD_UNLOCK(*balancer)) != APR_SUCCESS) {
          ap_log_rerror(APLOG_MARK, APLOG_ERR, rv, r, APLOGNO(01169)
                        "%s: Unlock failed for pre_request",
                        (*balancer)->s->name);
      }
      if (!*worker) {
          runtime = find_best_worker(*balancer, r);
          if (!runtime) {
              if ((*balancer)->workers->nelts) {
                  ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, APLOGNO(01170)
                                "%s: All workers are in error state",
                                (*balancer)->s->name);
              } else {
                  ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, APLOGNO(01171)
                                "%s: No workers in balancer",
                                (*balancer)->s->name);
              }
  
              return HTTP_SERVICE_UNAVAILABLE;
          }
          if (*(*balancer)->s->sticky && runtime) {
              /*
               * This balancer has sticky sessions and the client either has not
               * supplied any routing information or all workers for this route
               * including possible redirect and hotstandby workers are in error
               * state, but we have found another working worker for this
               * balancer where we can send the request. Thus notice that we have
               * changed the route to the backend.
               */
              apr_table_setn(r->subprocess_env, "BALANCER_ROUTE_CHANGED", "1");
          }
          *worker = runtime;
      }
  
      (*worker)->s->busy++;
      apr_pool_cleanup_register(r->pool, *worker, decrement_busy_count,
                                apr_pool_cleanup_null);
  
      /* Add balancer/worker info to env. */
      apr_table_setn(r->subprocess_env,
                     "BALANCER_NAME", (*balancer)->s->name);
      apr_table_setn(r->subprocess_env,
                     "BALANCER_WORKER_NAME", (*worker)->s->name);
      apr_table_setn(r->subprocess_env,
                     "BALANCER_WORKER_ROUTE", (*worker)->s->route);
  
      /* Rewrite the url from 'balancer://url'
       * to the 'worker_scheme://worker_hostname[:worker_port]/url'
       * This replaces the balancers fictional name with the
       * real hostname of the elected worker.
       */
      access_status = rewrite_url(r, *worker, url);
      /* Add the session route to request notes if present */
      if (route) {
          apr_table_setn(r->notes, "session-sticky", sticky);
          apr_table_setn(r->notes, "session-route", route);
  
          /* Add session info to env. */
          apr_table_setn(r->subprocess_env,
                         "BALANCER_SESSION_STICKY", sticky);
          apr_table_setn(r->subprocess_env,
                         "BALANCER_SESSION_ROUTE", route);
      }
      ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(01172)
                    "%s: worker (%s) rewritten to %s",
                    (*balancer)->s->name, (*worker)->s->name, *url);
  
      return access_status;
  }
  
  static int proxy_balancer_post_request(proxy_worker *worker,
                                         proxy_balancer *balancer,
                                         request_rec *r,
                                         proxy_server_conf *conf)
  {
  
      apr_status_t rv;
  
      if ((rv = PROXY_THREAD_LOCK(balancer)) != APR_SUCCESS) {
          ap_log_rerror(APLOG_MARK, APLOG_ERR, rv, r, APLOGNO(01173)
                        "%s: Lock failed for post_request",
                        balancer->s->name);
          return HTTP_INTERNAL_SERVER_ERROR;
      }
  
      if (!apr_is_empty_array(balancer->errstatuses)) {
          int i;
          for (i = 0; i < balancer->errstatuses->nelts; i++) {
              int val = ((int *)balancer->errstatuses->elts)[i];
              if (r->status == val) {
                  ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, APLOGNO(01174)
                                "%s: Forcing worker (%s) into error state " 
                                "due to status code %d matching 'failonstatus' "
                                "balancer parameter",
                                balancer->s->name, worker->s->name, val);
                  worker->s->status |= PROXY_WORKER_IN_ERROR;
                  worker->s->error_time = apr_time_now();
                  break;
              }
          }
      }
  
      if ((rv = PROXY_THREAD_UNLOCK(balancer)) != APR_SUCCESS) {
          ap_log_rerror(APLOG_MARK, APLOG_ERR, rv, r, APLOGNO(01175)
                        "%s: Unlock failed for post_request", balancer->s->name);
      }
      ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(01176)
                    "proxy_balancer_post_request for (%s)", balancer->s->name);
  
      return OK;
  }
  
  static void recalc_factors(proxy_balancer *balancer)
  {
      int i;
      proxy_worker **workers;
  
  
      /* Recalculate lbfactors */
      workers = (proxy_worker **)balancer->workers->elts;
      /* Special case if there is only one worker its
       * load factor will always be 1
       */
      if (balancer->workers->nelts == 1) {
          (*workers)->s->lbstatus = (*workers)->s->lbfactor = 1;
          return;
      }
      for (i = 0; i < balancer->workers->nelts; i++) {
          /* Update the status entries */
          workers[i]->s->lbstatus = workers[i]->s->lbfactor;
      }
  }
  
  static apr_status_t lock_remove(void *data)
  {
      int i;
      proxy_balancer *balancer;
      server_rec *s = data;
      void *sconf = s->module_config;
      proxy_server_conf *conf = (proxy_server_conf *) ap_get_module_config(sconf, &proxy_module);
  
      balancer = (proxy_balancer *)conf->balancers->elts;
      for (i = 0; i < conf->balancers->nelts; i++, balancer++) {
          if (balancer->gmutex) {
              apr_global_mutex_destroy(balancer->gmutex);
              balancer->gmutex = NULL;
          }
      }
      return(0);
  }
  
  /* post_config hook: */
  static int balancer_post_config(apr_pool_t *pconf, apr_pool_t *plog,
                           apr_pool_t *ptemp, server_rec *s)
  {
      apr_status_t rv;
      proxy_server_conf *conf;
      ap_slotmem_instance_t *new = NULL;
      apr_time_t tstamp;
  
      /* balancer_post_config() will be called twice during startup.  So, don't
       * set up the static data the 1st time through. */
      if (ap_state_query(AP_SQ_MAIN_STATE) == AP_SQ_MS_CREATE_PRE_CONFIG) {
          return OK;
      }
  
      if (!ap_proxy_retry_worker_fn) {
          ap_proxy_retry_worker_fn =
                  APR_RETRIEVE_OPTIONAL_FN(ap_proxy_retry_worker);
          if (!ap_proxy_retry_worker_fn) {
              ap_log_error(APLOG_MARK, APLOG_EMERG, 0, s, APLOGNO(02230)
                           "mod_proxy must be loaded for mod_proxy_balancer");
              return !OK;
          }
      }
  
      /*
       * Get slotmem setups
       */
      storage = ap_lookup_provider(AP_SLOTMEM_PROVIDER_GROUP, "shm",
                                   AP_SLOTMEM_PROVIDER_VERSION);
      if (!storage) {
          ap_log_error(APLOG_MARK, APLOG_EMERG, 0, s, APLOGNO(01177)
                       "Failed to lookup provider 'shm' for '%s': is "
                       "mod_slotmem_shm loaded??",
                       AP_SLOTMEM_PROVIDER_GROUP);
          return !OK;
      }
  
      tstamp = apr_time_now();
      /*
       * Go thru each Vhost and create the shared mem slotmem for
       * each balancer's workers
       */
      while (s) {
          int i,j;
          char *id;
          proxy_balancer *balancer;
          ap_slotmem_type_t type;
          void *sconf = s->module_config;
          conf = (proxy_server_conf *)ap_get_module_config(sconf, &proxy_module);
          /*
           * During create_proxy_config() we created a dummy id. Now that
           * we have identifying info, we can create the real id
           */
          id = apr_psprintf(pconf, "%s.%s.%d.%s.%s.%u.%s",
                            (s->server_scheme ? s->server_scheme : "????"),
                            (s->server_hostname ? s->server_hostname : "???"),
                            (int)s->port,
                            (s->server_admin ? s->server_admin : "??"),
                            (s->defn_name ? s->defn_name : "?"),
                            s->defn_line_number,
                            (s->error_fname ? s->error_fname : DEFAULT_ERRORLOG));
          conf->id = apr_psprintf(pconf, "p%x",
                                  ap_proxy_hashfunc(id, PROXY_HASHFUNC_DEFAULT));
          if (conf->bslot) {
              /* Shared memory already created for this proxy_server_conf.
               */
              s = s->next;
              continue;
          }
          if (conf->bal_persist) {
              type = AP_SLOTMEM_TYPE_PREGRAB | AP_SLOTMEM_TYPE_PERSIST;
          } else {
              type = AP_SLOTMEM_TYPE_PREGRAB;
          }
          if (conf->balancers->nelts) {
              conf->max_balancers = conf->balancers->nelts + conf->bgrowth;
              ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(01178) "Doing balancers create: %d, %d (%d)",
                           (int)ALIGNED_PROXY_BALANCER_SHARED_SIZE,
                           (int)conf->balancers->nelts, conf->max_balancers);
  
              rv = storage->create(&new, conf->id,
                                   ALIGNED_PROXY_BALANCER_SHARED_SIZE,
                                   conf->max_balancers, type, pconf);
              if (rv != APR_SUCCESS) {
                  ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s, APLOGNO(01179) "balancer slotmem_create failed");
                  return !OK;
              }
              conf->bslot = new;
          }
          conf->storage = storage;
  
          /* Initialize shared scoreboard data */
          balancer = (proxy_balancer *)conf->balancers->elts;
          for (i = 0; i < conf->balancers->nelts; i++, balancer++) {
              proxy_worker **workers;
              proxy_worker *worker;
              proxy_balancer_shared *bshm;
              const char *sname;
              unsigned int index;
  
              /* now that we have the right id, we need to redo the sname field */
              ap_pstr2_alnum(pconf, balancer->s->name + sizeof(BALANCER_PREFIX) - 1,
                             &sname);
              sname = apr_pstrcat(pconf, conf->id, "_", sname, NULL);
              PROXY_STRNCPY(balancer->s->sname, sname); /* We know this will succeed */
  
              balancer->max_workers = balancer->workers->nelts + balancer->growth;
  
              /* Create global mutex */
              rv = ap_global_mutex_create(&(balancer->gmutex), NULL, balancer_mutex_type,
                                          balancer->s->sname, s, pconf, 0);
              if (rv != APR_SUCCESS || !balancer->gmutex) {
                  ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s, APLOGNO(01180)
                               "mutex creation of %s : %s failed", balancer_mutex_type,
                               balancer->s->sname);
                  return HTTP_INTERNAL_SERVER_ERROR;
              }
  
              apr_pool_cleanup_register(pconf, (void *)s, lock_remove,
                                        apr_pool_cleanup_null);
  
              /* setup shm for balancers */
              bshm = ap_proxy_find_balancershm(storage, conf->bslot, balancer, &index);
              if (bshm) {
                  if ((rv = storage->fgrab(conf->bslot, index)) != APR_SUCCESS) {
                      ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s, APLOGNO(02408) "balancer slotmem_fgrab failed");
                      return !OK;
                  }
              }
              else {
                  if ((rv = storage->grab(conf->bslot, &index)) != APR_SUCCESS) {
                      ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s, APLOGNO(01181) "balancer slotmem_grab failed");
                      return !OK;
                  }
                  if ((rv = storage->dptr(conf->bslot, index, (void *)&bshm)) != APR_SUCCESS) {
                      ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s, APLOGNO(01182) "balancer slotmem_dptr failed");
                      return !OK;
                  }
              }
              if ((rv = ap_proxy_share_balancer(balancer, bshm, index)) != APR_SUCCESS) {
                  ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s, APLOGNO(01183) "Cannot share balancer");
                  return !OK;
              }
  
              /* create slotmem slots for workers */
              ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(01184) "Doing workers create: %s (%s), %d, %d [%u]",
                           balancer->s->name, balancer->s->sname,
                           (int)ALIGNED_PROXY_WORKER_SHARED_SIZE,
                           (int)balancer->max_workers, i);
  
              rv = storage->create(&new, balancer->s->sname,
                                   ALIGNED_PROXY_WORKER_SHARED_SIZE,
                                   balancer->max_workers, type, pconf);
              if (rv != APR_SUCCESS) {
                  ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s, APLOGNO(01185) "worker slotmem_create failed");
                  return !OK;
              }
              balancer->wslot = new;
              balancer->storage = storage;
  
              /* sync all timestamps */
              balancer->wupdated = balancer->s->wupdated = tstamp;
  
              /* now go thru each worker */
              workers = (proxy_worker **)balancer->workers->elts;
              for (j = 0; j < balancer->workers->nelts; j++, workers++) {
                  proxy_worker_shared *shm;
  
                  worker = *workers;
  
                  shm = ap_proxy_find_workershm(storage, balancer->wslot, worker, &index);
                  if (shm) {
                      if ((rv = storage->fgrab(balancer->wslot, index)) != APR_SUCCESS) {
                          ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s, APLOGNO(02409) "worker slotmem_fgrab failed");
                          return !OK;
                      }
                  }
                  else {
                      if ((rv = storage->grab(balancer->wslot, &index)) != APR_SUCCESS) {
                          ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s, APLOGNO(01186) "worker slotmem_grab failed");
                          return !OK;
  
                      }
                      if ((rv = storage->dptr(balancer->wslot, index, (void *)&shm)) != APR_SUCCESS) {
                          ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s, APLOGNO(01187) "worker slotmem_dptr failed");
                          return !OK;
                      }
                  }
                  if ((rv = ap_proxy_share_worker(worker, shm, index)) != APR_SUCCESS) {
                      ap_log_error(APLOG_MARK, APLOG_EMERG, rv, s, APLOGNO(01188) "Cannot share worker");
                      return !OK;
                  }
                  worker->s->updated = tstamp;
              }
              if (conf->bal_persist) {
                  /* We could have just read-in a persisted config. Force a sync. */
                  balancer->wupdated--;
                  ap_proxy_sync_balancer(balancer, s, conf);
              }
          }
          s = s->next;
      }
  
      return OK;
  }
  
  static void create_radio(const char *name, unsigned int flag, request_rec *r)
  {
      ap_rvputs(r, "<td>On <input name='", name, "' id='", name, "' value='1' type=radio", NULL);
      if (flag)
          ap_rputs(" checked", r);
      ap_rvputs(r, "> <br/> Off <input name='", name, "' id='", name, "' value='0' type=radio", NULL);
      if (!flag)
          ap_rputs(" checked", r);
      ap_rputs("></td>\n", r);
  }
  
  static void push2table(const char *input, apr_table_t *params,
                         const char *allowed[], apr_pool_t *p)
  {
      char *args;
      char *tok, *val;
      char *key;
  
      if (input == NULL) {
          return;
      }
      args = apr_pstrdup(p, input);
  
      key = apr_strtok(args, "&", &tok);
      while (key) {
          val = strchr(key, '=');
          if (val) {
              *val++ = '\0';
          }
          else {
              val = "";
          }
          ap_unescape_url(key);
          ap_unescape_url(val);
          if (allowed == NULL) { /* allow all */
              apr_table_set(params, key, val);
          }
          else {
              const char **ok = allowed;
              while (*ok) {
                  if (strcmp(*ok, key) == 0) {
                      apr_table_set(params, key, val);
                      break;
                  }
                  ok++;
              }
          }
          key = apr_strtok(NULL, "&", &tok);
      }
  }
  
  /* Manages the loadfactors and member status
   *   The balancer, worker and nonce are obtained from
   *   the request args (?b=...&w=...&nonce=....).
   *   All other params are pulled from any POST
   *   data that exists.
   * TODO:
   *   /.../<whatever>/balancer/worker/nonce
   */
  static int balancer_handler(request_rec *r)
  {
      void *sconf;
      proxy_server_conf *conf;
      proxy_balancer *balancer, *bsel = NULL;
      proxy_worker *worker, *wsel = NULL;
      proxy_worker **workers = NULL;
      apr_table_t *params;
      int i, n;
      int ok2change = 1;
      const char *name;
      const char *action;
      apr_status_t rv;
  
      /* is this for us? */
      if (strcmp(r->handler, "balancer-manager")) {
          return DECLINED;
      }
  
      r->allowed = 0
      | (AP_METHOD_BIT << M_GET)
      | (AP_METHOD_BIT << M_POST);
      if ((r->method_number != M_GET) && (r->method_number != M_POST)) {
          return DECLINED;
      }
  
      sconf = r->server->module_config;
      conf = (proxy_server_conf *) ap_get_module_config(sconf, &proxy_module);
      params = apr_table_make(r->pool, 10);
  
      balancer = (proxy_balancer *)conf->balancers->elts;
      for (i = 0; i < conf->balancers->nelts; i++, balancer++) {
          if ((rv = PROXY_THREAD_LOCK(balancer)) != APR_SUCCESS) {
              ap_log_rerror(APLOG_MARK, APLOG_ERR, rv, r, APLOGNO(01189)
                            "%s: Lock failed for balancer_handler",
                            balancer->s->name);
          }
          ap_proxy_sync_balancer(balancer, r->server, conf);
          if ((rv = PROXY_THREAD_UNLOCK(balancer)) != APR_SUCCESS) {
              ap_log_rerror(APLOG_MARK, APLOG_ERR, rv, r, APLOGNO(01190)
                            "%s: Unlock failed for balancer_handler",
                            balancer->s->name);
          }
      }
  
      if (r->args && (r->method_number == M_GET)) {
          const char *allowed[] = { "w", "b", "nonce", "xml", NULL };
          ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(01191) "parsing r->args");
  
          push2table(r->args, params, allowed, r->pool);
      }
      if (r->method_number == M_POST) {
          apr_bucket_brigade *ib;
          apr_size_t len = 1024;
          char *buf = apr_pcalloc(r->pool, len+1);
  
          ib = apr_brigade_create(r->connection->pool, r->connection->bucket_alloc);
          rv = ap_get_brigade(r->input_filters, ib, AP_MODE_READBYTES,
                                  APR_BLOCK_READ, len);
          if (rv != APR_SUCCESS) {
              return HTTP_INTERNAL_SERVER_ERROR;
          }
          apr_brigade_flatten(ib, buf, &len);
          buf[len] = '\0';
          push2table(buf, params, NULL, r->pool);
      }
      if ((name = apr_table_get(params, "b")))
          bsel = ap_proxy_get_balancer(r->pool, conf,
              apr_pstrcat(r->pool, BALANCER_PREFIX, name, NULL), 0);
  
      if ((name = apr_table_get(params, "w"))) {
          wsel = ap_proxy_get_worker(r->pool, bsel, conf, name);
      }
  
  
      /* Check that the supplied nonce matches this server's nonce;
       * otherwise ignore all parameters, to prevent a CSRF attack. */
      if (!bsel ||
          (*bsel->s->nonce &&
           (
            (name = apr_table_get(params, "nonce")) == NULL ||
            strcmp(bsel->s->nonce, name) != 0
           )
          )
         ) {
          apr_table_clear(params);
          ok2change = 0;
      }
  
      /* First set the params */
      if (wsel && ok2change) {
          const char *val;
          int was_usable = PROXY_WORKER_IS_USABLE(wsel);
  
          ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(01192) "settings worker params");
  
          if ((val = apr_table_get(params, "w_lf"))) {
              int ival = atoi(val);
              if (ival >= 1 && ival <= 100) {
                  wsel->s->lbfactor = ival;
                  if (bsel)
                      recalc_factors(bsel);
              }
          }
          if ((val = apr_table_get(params, "w_wr"))) {
              if (strlen(val) && strlen(val) < sizeof(wsel->s->route))
                  strcpy(wsel->s->route, val);
              else
                  *wsel->s->route = '\0';
          }
          if ((val = apr_table_get(params, "w_rr"))) {
              if (strlen(val) && strlen(val) < sizeof(wsel->s->redirect))
                  strcpy(wsel->s->redirect, val);
              else
                  *wsel->s->redirect = '\0';
          }
          if ((val = apr_table_get(params, "w_status_I"))) {
              ap_proxy_set_wstatus('I', atoi(val), wsel);
          }
          if ((val = apr_table_get(params, "w_status_N"))) {
              ap_proxy_set_wstatus('N', atoi(val), wsel);
          }
          if ((val = apr_table_get(params, "w_status_D"))) {
              ap_proxy_set_wstatus('D', atoi(val), wsel);
          }
          if ((val = apr_table_get(params, "w_status_H"))) {
              ap_proxy_set_wstatus('H', atoi(val), wsel);
          }
          if ((val = apr_table_get(params, "w_ls"))) {
              int ival = atoi(val);
              if (ival >= 0 && ival <= 99) {
                  wsel->s->lbset = ival;
               }
          }
          /* if enabling, we need to reset all lb params */
          if (bsel && !was_usable && PROXY_WORKER_IS_USABLE(wsel)) {
              bsel->s->need_reset = 1;
          }
  
      }
  
      if (bsel && ok2change) {
          const char *val;
          int ival;
          ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(01193)
                        "settings balancer params");
          if ((val = apr_table_get(params, "b_lbm"))) {
              if ((strlen(val) < (sizeof(bsel->s->lbpname)-1)) &&
                  strcmp(val, bsel->s->lbpname)) {
                  proxy_balancer_method *lbmethod;
                  lbmethod = ap_lookup_provider(PROXY_LBMETHOD, val, "0");
                  if (lbmethod) {
                      PROXY_STRNCPY(bsel->s->lbpname, val);
                      bsel->lbmethod = lbmethod;
                      bsel->s->wupdated = apr_time_now();
                      bsel->s->need_reset = 1;
                  }
              }
          }
          if ((val = apr_table_get(params, "b_tmo"))) {
              ival = atoi(val);
              if (ival >= 0 && ival <= 7200) { /* 2 hrs enuff? */
                  bsel->s->timeout = apr_time_from_sec(ival);
              }
          }
          if ((val = apr_table_get(params, "b_max"))) {
              ival = atoi(val);
              if (ival >= 0 && ival <= 99) {
                  bsel->s->max_attempts = ival;
              }
          }
          if ((val = apr_table_get(params, "b_sforce"))) {
              ival = atoi(val);
              bsel->s->sticky_force = (ival != 0);
          }
          if ((val = apr_table_get(params, "b_ss")) && *val) {
              if (strlen(val) < (sizeof(bsel->s->sticky_path)-1)) {
                  if (*val == '-' && *(val+1) == '\0')
                      *bsel->s->sticky_path = *bsel->s->sticky = '\0';
                  else {
                      char *path;
                      PROXY_STRNCPY(bsel->s->sticky_path, val);
                      PROXY_STRNCPY(bsel->s->sticky, val);
  
                      if ((path = strchr((char *)bsel->s->sticky, '|'))) {
                          *path++ = '\0';
                          PROXY_STRNCPY(bsel->s->sticky_path, path);
                      }
                  }
              }
          }
          if ((val = apr_table_get(params, "b_wyes")) &&
              (*val == '1' && *(val+1) == '\0') &&
              (val = apr_table_get(params, "b_nwrkr"))) {
              char *ret;
              proxy_worker *nworker;
              nworker = ap_proxy_get_worker(conf->pool, bsel, conf, val);
              if (!nworker && storage->num_free_slots(bsel->wslot)) {
                  if ((rv = PROXY_GLOBAL_LOCK(bsel)) != APR_SUCCESS) {
                      ap_log_rerror(APLOG_MARK, APLOG_ERR, rv, r, APLOGNO(01194)
                                    "%s: Lock failed for adding worker",
                                    bsel->s->name);
                  }
                  ret = ap_proxy_define_worker(conf->pool, &nworker, bsel, conf, val, 0);
                  if (!ret) {
                      unsigned int index;
                      proxy_worker_shared *shm;
                      PROXY_COPY_CONF_PARAMS(nworker, conf);
                      if ((rv = storage->grab(bsel->wslot, &index)) != APR_SUCCESS) {
                          ap_log_rerror(APLOG_MARK, APLOG_EMERG, rv, r, APLOGNO(01195)
                                        "worker slotmem_grab failed");
                          if ((rv = PROXY_GLOBAL_UNLOCK(bsel)) != APR_SUCCESS) {
                              ap_log_rerror(APLOG_MARK, APLOG_ERR, rv, r, APLOGNO(01196)
                                            "%s: Unlock failed for adding worker",
                                            bsel->s->name);
                          }
                          return HTTP_BAD_REQUEST;
                      }
                      if ((rv = storage->dptr(bsel->wslot, index, (void *)&shm)) != APR_SUCCESS) {
                          ap_log_rerror(APLOG_MARK, APLOG_EMERG, rv, r, APLOGNO(01197)
                                        "worker slotmem_dptr failed");
                          if ((rv = PROXY_GLOBAL_UNLOCK(bsel)) != APR_SUCCESS) {
                              ap_log_rerror(APLOG_MARK, APLOG_ERR, rv, r, APLOGNO(01198)
                                            "%s: Unlock failed for adding worker",
                                            bsel->s->name);
                          }
                          return HTTP_BAD_REQUEST;
                      }
                      if ((rv = ap_proxy_share_worker(nworker, shm, index)) != APR_SUCCESS) {
                          ap_log_rerror(APLOG_MARK, APLOG_EMERG, rv, r, APLOGNO(01199)
                                        "Cannot share worker");
                          if ((rv = PROXY_GLOBAL_UNLOCK(bsel)) != APR_SUCCESS) {
                              ap_log_rerror(APLOG_MARK, APLOG_ERR, rv, r, APLOGNO(01200)
                                            "%s: Unlock failed for adding worker",
                                            bsel->s->name);
                          }
                          return HTTP_BAD_REQUEST;
                      }
                      if ((rv = ap_proxy_initialize_worker(nworker, r->server, conf->pool)) != APR_SUCCESS) {
                          ap_log_rerror(APLOG_MARK, APLOG_EMERG, rv, r, APLOGNO(01201)
                                        "Cannot init worker");
                          if ((rv = PROXY_GLOBAL_UNLOCK(bsel)) != APR_SUCCESS) {
                              ap_log_rerror(APLOG_MARK, APLOG_ERR, rv, r, APLOGNO(01202)
                                            "%s: Unlock failed for adding worker",
                                            bsel->s->name);
                          }
                          return HTTP_BAD_REQUEST;
                      }
                      /* sync all timestamps */
                      bsel->wupdated = bsel->s->wupdated = nworker->s->updated = apr_time_now();
                      /* by default, all new workers are disabled */
                      ap_proxy_set_wstatus('D', 1, nworker);
                  }
                  if ((rv = PROXY_GLOBAL_UNLOCK(bsel)) != APR_SUCCESS) {
                      ap_log_rerror(APLOG_MARK, APLOG_ERR, rv, r, APLOGNO(01203)
                                    "%s: Unlock failed for adding worker",
                                    bsel->s->name);
                  }
              }
  
          }
  
      }
  
      action = ap_construct_url(r->pool, r->uri, r);
      ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(01204) "genning page");
  
      if (apr_table_get(params, "xml")) {
          char date[APR_RFC822_DATE_LEN];
          ap_set_content_type(r, "text/xml");
          ap_rputs("<?xml version='1.0' encoding='UTF-8' ?>\n", r);
          ap_rputs("<httpd:manager xmlns:httpd='http://httpd.apache.org'>\n", r);
          ap_rputs("  <httpd:balancers>\n", r);
          balancer = (proxy_balancer *)conf->balancers->elts;
          for (i = 0; i < conf->balancers->nelts; i++) {
              ap_rputs("    <httpd:balancer>\n", r);
              /* Start proxy_balancer */
              ap_rvputs(r, "      <httpd:name>", balancer->s->name, "</httpd:name>\n", NULL);
              if (balancer->s->sticky) {
                  ap_rvputs(r, "      <httpd:stickysession>", balancer->s->sticky,
                            "</httpd:stickysession>\n", NULL);
                  ap_rprintf(r,
                             "      <httpd:nofailover>%s</httpd:nofailover>\n",
                             (balancer->s->sticky_force ? "On" : "Off"));
              }
              ap_rprintf(r,
                         "      <httpd:timeout>%" APR_TIME_T_FMT "</httpd:timeout>",
                         apr_time_sec(balancer->s->timeout));
              if (balancer->s->max_attempts_set) {
                  ap_rprintf(r,
                             "      <httpd:maxattempts>%d</httpd:maxattempts>\n",
                             balancer->s->max_attempts);
              }
              ap_rvputs(r, "      <httpd:lbmethod>", balancer->lbmethod->name,
                        "</httpd:lbmethod>\n", NULL);
              if (balancer->s->sticky) {
                  ap_rprintf(r,
                             "      <httpd:scolonpathdelim>%s</httpd:scolonpathdelim>\n",
                             (balancer->s->scolonsep ? "On" : "Off"));
              }
              /* End proxy_balancer */
              ap_rputs("      <httpd:workers>\n", r);
              workers = (proxy_worker **)balancer->workers->elts;
              for (n = 0; n < balancer->workers->nelts; n++) {
                  worker = *workers;
                  /* Start proxy_worker */
                  ap_rputs("        <httpd:worker>\n", r);
                  ap_rvputs(r, "          <httpd:name>", worker->s->name,
                            "</httpd:name>\n", NULL);
                  ap_rvputs(r, "          <httpd:scheme>", worker->s->scheme,
                            "</httpd:scheme>\n", NULL);
                  ap_rvputs(r, "          <httpd:hostname>", worker->s->hostname,
                            "</httpd:hostname>\n", NULL);
                  ap_rprintf(r, "          <httpd:loadfactor>%d</httpd:loadfactor>\n",
                            worker->s->lbfactor);
                  ap_rprintf(r,
                             "          <httpd:port>%d</httpd:port>\n",
                             worker->s->port);
                  ap_rprintf(r, "          <httpd:min>%d</httpd:min>\n",
                             worker->s->min);
                  ap_rprintf(r, "          <httpd:smax>%d</httpd:smax>\n",
                             worker->s->smax);
                  ap_rprintf(r, "          <httpd:max>%d</httpd:max>\n",
                             worker->s->hmax);
                  ap_rprintf(r,
                             "          <httpd:ttl>%" APR_TIME_T_FMT "</httpd:ttl>\n",
                             apr_time_sec(worker->s->ttl));
                  if (worker->s->timeout_set) {
                      ap_rprintf(r,
                                 "          <httpd:timeout>%" APR_TIME_T_FMT "</httpd:timeout>\n",
                                 apr_time_sec(worker->s->timeout));
                  }
                  if (worker->s->acquire_set) {
                      ap_rprintf(r,
                                 "          <httpd:acquire>%" APR_TIME_T_FMT "</httpd:acquire>\n",
                                 apr_time_msec(worker->s->acquire));
                  }
                  if (worker->s->recv_buffer_size_set) {
                      ap_rprintf(r,
                                 "          <httpd:recv_buffer_size>%" APR_SIZE_T_FMT "</httpd:recv_buffer_size>\n",
                                 worker->s->recv_buffer_size);
                  }
                  if (worker->s->io_buffer_size_set) {
                      ap_rprintf(r,
                                 "          <httpd:io_buffer_size>%" APR_SIZE_T_FMT "</httpd:io_buffer_size>\n",
                                 worker->s->io_buffer_size);
                  }
                  if (worker->s->keepalive_set) {
                      ap_rprintf(r,
                                 "          <httpd:keepalive>%s</httpd:keepalive>\n",
                                 (worker->s->keepalive ? "On" : "Off"));
                  }
                  /* Begin proxy_worker_stat */
                  ap_rputs("          <httpd:status>", r);
                  if (worker->s->status & PROXY_WORKER_DISABLED)
                      ap_rputs("Disabled", r);
                  else if (worker->s->status & PROXY_WORKER_IN_ERROR)
                      ap_rputs("Error", r);
                  else if (worker->s->status & PROXY_WORKER_STOPPED)
                      ap_rputs("Stopped", r);
                  else if (worker->s->status & PROXY_WORKER_HOT_STANDBY)
                      ap_rputs("Standby", r);
                  else if (PROXY_WORKER_IS_USABLE(worker))
                      ap_rputs("OK", r);
                  else if (!PROXY_WORKER_IS_INITIALIZED(worker))
                      ap_rputs("Uninitialized", r);
                  ap_rputs("</httpd:status>\n", r);
                  if ((worker->s->error_time > 0) && apr_rfc822_date(date, worker->s->error_time) == APR_SUCCESS) {
                      ap_rvputs(r, "          <httpd:error_time>", date,
                                "</httpd:error_time>\n", NULL);
                  }
                  ap_rprintf(r,
                             "          <httpd:retries>%d</httpd:retries>\n",
                             worker->s->retries);
                  ap_rprintf(r,
                             "          <httpd:lbstatus>%d</httpd:lbstatus>\n",
                             worker->s->lbstatus);
                  ap_rprintf(r,
                             "          <httpd:loadfactor>%d</httpd:loadfactor>\n",
                             worker->s->lbfactor);
                  ap_rprintf(r,
                             "          <httpd:transferred>%" APR_OFF_T_FMT "</httpd:transferred>\n",
                             worker->s->transferred);
                  ap_rprintf(r,
                             "          <httpd:read>%" APR_OFF_T_FMT "</httpd:read>\n",
                             worker->s->read);
                  ap_rprintf(r,
                             "          <httpd:elected>%" APR_SIZE_T_FMT "</httpd:elected>\n",
                             worker->s->elected);
                  ap_rvputs(r, "          <httpd:route>",
                            ap_escape_html(r->pool, worker->s->route),
                            "</httpd:route>\n", NULL);
                  ap_rvputs(r, "          <httpd:redirect>",
                            ap_escape_html(r->pool, worker->s->redirect),
                            "</httpd:redirect>\n", NULL);
                  ap_rprintf(r,
                             "          <httpd:busy>%" APR_SIZE_T_FMT "</httpd:busy>\n",
                             worker->s->busy);
                  ap_rprintf(r, "          <httpd:lbset>%d</httpd:lbset>\n",
                             worker->s->lbset);
                  /* End proxy_worker_stat */
                  if (!strcasecmp(worker->s->scheme, "ajp")) {
                      ap_rputs("          <httpd:flushpackets>", r);
                      switch (worker->s->flush_packets) {
                          case flush_off:
                              ap_rputs("Off", r);
                              break;
                          case flush_on:
                              ap_rputs("On", r);
                              break;
                          case flush_auto:
                              ap_rputs("Auto", r);
                              break;
                      }
                      ap_rputs("</httpd:flushpackets>\n", r);
                      if (worker->s->flush_packets == flush_auto) {
                          ap_rprintf(r,
                                     "          <httpd:flushwait>%d</httpd:flushwait>\n",
                                     worker->s->flush_wait);
                      }
                      if (worker->s->ping_timeout_set) {
                          ap_rprintf(r,
                                     "          <httpd:ping>%" APR_TIME_T_FMT "</httpd:ping>",
                                     apr_time_msec(worker->s->ping_timeout));
                      }
                  }
                  if (worker->s->disablereuse_set) {
                      ap_rprintf(r,
                                 "      <httpd:disablereuse>%s</httpd:disablereuse>\n",
                                 (worker->s->disablereuse ? "On" : "Off"));
                  }
                  if (worker->s->conn_timeout_set) {
                      ap_rprintf(r,
                                 "          <httpd:connectiontimeout>%" APR_TIME_T_FMT "</httpd:connectiontimeout>\n",
                                 apr_time_msec(worker->s->conn_timeout));
                  }
                  if (worker->s->retry_set) {
                      ap_rprintf(r,
                                 "          <httpd:retry>%" APR_TIME_T_FMT "</httpd:retry>\n",
                                 apr_time_sec(worker->s->retry));
                  }
                  ap_rputs("        </httpd:worker>\n", r);
                  ++workers;
              }
              ap_rputs("      </httpd:workers>\n", r);
              ap_rputs("    </httpd:balancer>\n", r);
              ++balancer;
          }
          ap_rputs("  </httpd:balancers>\n", r);
          ap_rputs("</httpd:manager>", r);
      }
      else {
          ap_set_content_type(r, "text/html; charset=ISO-8859-1");
          ap_rputs(DOCTYPE_HTML_3_2
                   "<html><head><title>Balancer Manager</title>\n", r);
          ap_rputs("<style type='text/css'>\n"
                   "table {\n"
                   " border-width: 1px;\n"
                   " border-spacing: 3px;\n"
                   " border-style: solid;\n"
                   " border-color: gray;\n"
                   " border-collapse: collapse;\n"
                   " background-color: white;\n"
                   " text-align: center;\n"
                   "}\n"
                   "th {\n"
                   " border-width: 1px;\n"
                   " padding: 2px;\n"
                   " border-style: dotted;\n"
                   " border-color: gray;\n"
                   " background-color: white;\n"
                   " text-align: center;\n"
                   "}\n"
                   "td {\n"
                   " border-width: 1px;\n"
                   " padding: 2px;\n"
                   " border-style: dotted;\n"
                   " border-color: gray;\n"
                   " background-color: white;\n"
                   " text-align: center;\n"
                   "}\n"
                   "</style>\n</head>\n", r);
          ap_rputs("<body><h1>Load Balancer Manager for ", r);
          ap_rvputs(r, ap_escape_html(r->pool, ap_get_server_name(r)),
                    "</h1>\n\n", NULL);
          ap_rvputs(r, "<dl><dt>Server Version: ",
                    ap_get_server_description(), "</dt>\n", NULL);
          ap_rvputs(r, "<dt>Server Built: ",
                    ap_get_server_built(), "\n</dt></dl>\n", NULL);
          balancer = (proxy_balancer *)conf->balancers->elts;
          for (i = 0; i < conf->balancers->nelts; i++) {
  
              ap_rputs("<hr />\n<h3>LoadBalancer Status for ", r);
              ap_rvputs(r, "<a href=\"", ap_escape_uri(r->pool, r->uri), "?b=",
                        balancer->s->name + sizeof(BALANCER_PREFIX) - 1,
                        "&nonce=", balancer->s->nonce,
                        "\">", NULL);
              ap_rvputs(r, balancer->s->name, "</a> [",balancer->s->sname, "]</h3>\n", NULL);
              ap_rputs("\n\n<table><tr>"
                  "<th>MaxMembers</th><th>StickySession</th><th>DisableFailover</th><th>Timeout</th><th>FailoverAttempts</th><th>Method</th>"
                  "<th>Path</th><th>Active</th></tr>\n<tr>", r);
              /* the below is a safe cast, since the number of slots total will
               * never be more than max_workers, which is restricted to int */
              ap_rprintf(r, "<td>%d [%d Used]</td>\n", balancer->max_workers,
                         balancer->max_workers - (int)storage->num_free_slots(balancer->wslot));
              if (*balancer->s->sticky) {
                  if (strcmp(balancer->s->sticky, balancer->s->sticky_path)) {
                      ap_rvputs(r, "<td>", balancer->s->sticky, " | ",
                                balancer->s->sticky_path, NULL);
                  }
                  else {
                      ap_rvputs(r, "<td>", balancer->s->sticky, NULL);
                  }
              }
              else {
                  ap_rputs("<td> (None) ", r);
              }
              ap_rprintf(r, "<td>%s</td>\n",
                         balancer->s->sticky_force ? "On" : "Off");
              ap_rprintf(r, "</td><td>%" APR_TIME_T_FMT "</td>",
                  apr_time_sec(balancer->s->timeout));
              ap_rprintf(r, "<td>%d</td>\n", balancer->s->max_attempts);
              ap_rprintf(r, "<td>%s</td>\n",
                         balancer->s->lbpname);
              ap_rputs("<td>", r);
              if (balancer->s->vhost && *(balancer->s->vhost)) {
                  ap_rvputs(r, balancer->s->vhost, " -> ", NULL);
              }
              ap_rvputs(r, balancer->s->vpath, "</td>\n", NULL);
              ap_rprintf(r, "<td>%s</td>\n",
                         !balancer->s->inactive ? "Yes" : "No");
              ap_rputs("</table>\n<br />", r);
              ap_rputs("\n\n<table><tr>"
                  "<th>Worker URL</th>"
                  "<th>Route</th><th>RouteRedir</th>"
                  "<th>Factor</th><th>Set</th><th>Status</th>"
                  "<th>Elected</th><th>Busy</th><th>Load</th><th>To</th><th>From</th>"
                  "</tr>\n", r);
  
              workers = (proxy_worker **)balancer->workers->elts;
              for (n = 0; n < balancer->workers->nelts; n++) {
                  char fbuf[50];
                  worker = *workers;
                  ap_rvputs(r, "<tr>\n<td><a href=\"",
                            ap_escape_uri(r->pool, r->uri), "?b=",
                            balancer->s->name + sizeof(BALANCER_PREFIX) - 1, "&w=",
                            ap_escape_uri(r->pool, worker->s->name),
                            "&nonce=", balancer->s->nonce,
                            "\">", NULL);
                  ap_rvputs(r, worker->s->name, "</a></td>", NULL);
                  ap_rvputs(r, "<td>", ap_escape_html(r->pool, worker->s->route),
                            NULL);
                  ap_rvputs(r, "</td><td>",
                            ap_escape_html(r->pool, worker->s->redirect), NULL);
                  ap_rprintf(r, "</td><td>%d</td>", worker->s->lbfactor);
                  ap_rprintf(r, "<td>%d</td><td>", worker->s->lbset);
                  ap_rvputs(r, ap_proxy_parse_wstatus(r->pool, worker), NULL);
                  ap_rputs("</td>", r);
                  ap_rprintf(r, "<td>%" APR_SIZE_T_FMT "</td>", worker->s->elected);
                  ap_rprintf(r, "<td>%" APR_SIZE_T_FMT "</td>", worker->s->busy);
                  ap_rprintf(r, "<td>%d</td><td>", worker->s->lbstatus);
                  ap_rputs(apr_strfsize(worker->s->transferred, fbuf), r);
                  ap_rputs("</td><td>", r);
                  ap_rputs(apr_strfsize(worker->s->read, fbuf), r);
                  ap_rputs("</td></tr>\n", r);
  
                  ++workers;
              }
              ap_rputs("</table>\n", r);
              ++balancer;
          }
          ap_rputs("<hr />\n", r);
          if (wsel && bsel) {
              ap_rputs("<h3>Edit worker settings for ", r);
              ap_rvputs(r, wsel->s->name, "</h3>\n", NULL);
              ap_rputs("<form method=\"POST\" enctype=\"application/x-www-form-urlencoded\" action=\"", r);
              ap_rvputs(r, ap_escape_uri(r->pool, action), "\">\n", NULL);
              ap_rputs("<dl>\n<table><tr><td>Load factor:</td><td><input name='w_lf' id='w_lf' type=text ", r);
              ap_rprintf(r, "value='%d'></td></tr>\n", wsel->s->lbfactor);
              ap_rputs("<tr><td>LB Set:</td><td><input name='w_ls' id='w_ls' type=text ", r);
              ap_rprintf(r, "value='%d'></td></tr>\n", wsel->s->lbset);
              ap_rputs("<tr><td>Route:</td><td><input name='w_wr' id='w_wr' type=text ", r);
              ap_rvputs(r, "value=\"", ap_escape_html(r->pool, wsel->s->route),
                        NULL);
              ap_rputs("\"></td></tr>\n", r);
              ap_rputs("<tr><td>Route Redirect:</td><td><input name='w_rr' id='w_rr' type=text ", r);
              ap_rvputs(r, "value=\"", ap_escape_html(r->pool, wsel->s->redirect),
                        NULL);
              ap_rputs("\"></td></tr>\n", r);
              ap_rputs("<tr><td>Status:</td>", r);
              ap_rputs("<td><table><tr>"
                       "<th>Ignore Errors</th>"
                       "<th>Draining Mode</th>"
                       "<th>Disabled</th>"
                       "<th>Hot Standby</th></tr>\n<tr>", r);
              create_radio("w_status_I", (PROXY_WORKER_IGNORE_ERRORS & wsel->s->status), r);
              create_radio("w_status_N", (PROXY_WORKER_DRAIN & wsel->s->status), r);
              create_radio("w_status_D", (PROXY_WORKER_DISABLED & wsel->s->status), r);
              create_radio("w_status_H", (PROXY_WORKER_HOT_STANDBY & wsel->s->status), r);
              ap_rputs("</tr></table>\n", r);
              ap_rputs("<tr><td colspan=2><input type=submit value='Submit'></td></tr>\n", r);
              ap_rvputs(r, "</table>\n<input type=hidden name='w' id='w' ",  NULL);
              ap_rvputs(r, "value='", ap_escape_uri(r->pool, wsel->s->name), "'>\n", NULL);
              ap_rvputs(r, "<input type=hidden name='b' id='b' ", NULL);
              ap_rvputs(r, "value='", bsel->s->name + sizeof(BALANCER_PREFIX) - 1,
                        "'>\n", NULL);
              ap_rvputs(r, "<input type=hidden name='nonce' id='nonce' value='",
                        bsel->s->nonce, "'>\n", NULL);
              ap_rputs("</form>\n", r);
              ap_rputs("<hr />\n", r);
          } else if (bsel) {
              const apr_array_header_t *provs;
              const ap_list_provider_names_t *pname;
              int i;
              ap_rputs("<h3>Edit balancer settings for ", r);
              ap_rvputs(r, bsel->s->name, "</h3>\n", NULL);
              ap_rputs("<form method='POST' enctype='application/x-www-form-urlencoded' action='", r);
              ap_rvputs(r, action, "'>\n", NULL);
              ap_rputs("<dl>\n<table>\n", r);
              provs = ap_list_provider_names(r->pool, PROXY_LBMETHOD, "0");
              if (provs) {
                  ap_rputs("<tr><td>LBmethod:</td>", r);
                  ap_rputs("<td>\n<select name='b_lbm' id='b_lbm'>", r);
                  pname = (ap_list_provider_names_t *)provs->elts;
                  for (i = 0; i < provs->nelts; i++, pname++) {
                      ap_rvputs(r,"<option value='", pname->provider_name, "'", NULL);
                      if (strcmp(pname->provider_name, bsel->s->lbpname) == 0)
                          ap_rputs(" selected ", r);
                      ap_rvputs(r, ">", pname->provider_name, "\n", NULL);
                  }
                  ap_rputs("</select>\n</td></tr>\n", r);
              }
              ap_rputs("<tr><td>Timeout:</td><td><input name='b_tmo' id='b_tmo' type=text ", r);
              ap_rprintf(r, "value='%" APR_TIME_T_FMT "'></td></tr>\n", apr_time_sec(bsel->s->timeout));
              ap_rputs("<tr><td>Failover Attempts:</td><td><input name='b_max' id='b_max' type=text ", r);
              ap_rprintf(r, "value='%d'></td></tr>\n", bsel->s->max_attempts);
              ap_rputs("<tr><td>Disable Failover:</td>", r);
              create_radio("b_sforce", bsel->s->sticky_force, r);
              ap_rputs("<tr><td>Sticky Session:</td><td><input name='b_ss' id='b_ss' size=64 type=text ", r);
              if (strcmp(bsel->s->sticky, bsel->s->sticky_path)) {
                  ap_rvputs(r, "value ='", bsel->s->sticky, " | ",
                            bsel->s->sticky_path, NULL);
              }
              else {
                  ap_rvputs(r, "value ='", bsel->s->sticky, NULL);
              }
              ap_rputs("'>&nbsp;&nbsp;&nbsp;&nbsp;(Use '-' to delete)</td></tr>\n", r);
              if (storage->num_free_slots(bsel->wslot) != 0) {
                  ap_rputs("<tr><td>Add New Worker:</td><td><input name='b_nwrkr' id='b_nwrkr' size=32 type=text>"
                           "&nbsp;&nbsp;&nbsp;&nbsp;Are you sure? <input name='b_wyes' id='b_wyes' type=checkbox value='1'>"
                           "</td></tr>", r);
              }
              ap_rputs("<tr><td colspan=2><input type=submit value='Submit'></td></tr>\n", r);
              ap_rvputs(r, "</table>\n<input type=hidden name='b' id='b' ", NULL);
              ap_rvputs(r, "value='", bsel->s->name + sizeof(BALANCER_PREFIX) - 1,
                        "'>\n", NULL);
              ap_rvputs(r, "<input type=hidden name='nonce' id='nonce' value='",
                        bsel->s->nonce, "'>\n", NULL);
              ap_rputs("</form>\n", r);
              ap_rputs("<hr />\n", r);
          }
          ap_rputs(ap_psignature("",r), r);
          ap_rputs("</body></html>\n", r);
          ap_rflush(r);
      }
      return DONE;
  }
  
  static void balancer_child_init(apr_pool_t *p, server_rec *s)
  {
      while (s) {
          proxy_balancer *balancer;
          int i;
          void *sconf = s->module_config;
          proxy_server_conf *conf = (proxy_server_conf *)ap_get_module_config(sconf, &proxy_module);
          apr_status_t rv;
  
          if (conf->balancers->nelts) {
              apr_size_t size;
              unsigned int num;
              storage->attach(&(conf->bslot), conf->id, &size, &num, p);
              if (!conf->bslot) {
                  ap_log_error(APLOG_MARK, APLOG_EMERG, 0, s, APLOGNO(01205) "slotmem_attach failed");
                  exit(1); /* Ugly, but what else? */
              }
          }
  
          balancer = (proxy_balancer *)conf->balancers->elts;
          for (i = 0; i < conf->balancers->nelts; i++, balancer++) {
              rv = ap_proxy_initialize_balancer(balancer, s, p);
  
              if (rv != APR_SUCCESS) {
                  ap_log_error(APLOG_MARK, APLOG_CRIT, rv, s, APLOGNO(01206)
                               "Failed to init balancer %s in child",
                               balancer->s->name);
                  exit(1); /* Ugly, but what else? */
              }
              init_balancer_members(conf->pool, s, balancer);
          }
          s = s->next;
      }
  
  }
  
  static void ap_proxy_balancer_register_hook(apr_pool_t *p)
  {
      /* Only the mpm_winnt has child init hook handler.
       * make sure that we are called after the mpm
       * initializes
       */
      static const char *const aszPred[] = { "mpm_winnt.c", "mod_slotmem_shm.c", NULL};
       /* manager handler */
      ap_hook_post_config(balancer_post_config, NULL, NULL, APR_HOOK_MIDDLE);
      ap_hook_pre_config(balancer_pre_config, NULL, NULL, APR_HOOK_MIDDLE);
      ap_hook_handler(balancer_handler, NULL, NULL, APR_HOOK_FIRST);
      ap_hook_child_init(balancer_child_init, aszPred, NULL, APR_HOOK_MIDDLE);
      proxy_hook_pre_request(proxy_balancer_pre_request, NULL, NULL, APR_HOOK_FIRST);
      proxy_hook_post_request(proxy_balancer_post_request, NULL, NULL, APR_HOOK_FIRST);
      proxy_hook_canon_handler(proxy_balancer_canon, NULL, NULL, APR_HOOK_FIRST);
  }
  
  AP_DECLARE_MODULE(proxy_balancer) = {
      STANDARD20_MODULE_STUFF,
      NULL,       /* create per-directory config structure */
      NULL,       /* merge per-directory config structures */
      NULL,       /* create per-server config structure */
      NULL,       /* merge per-server config structures */
      NULL,       /* command apr_table_t */
      ap_proxy_balancer_register_hook /* register hooks */
  };
  