source3/lib/server_prefork_util.c

   1 /*
   2    Unix SMB/Netbios implementation.
   3    Prefork Helpers
   4    Copyright (C) Simo Sorce <idra@samba.org> 2011
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18 */
  19
  20 #include "includes.h"
  21 #include "lib/server_prefork.h"
  22 #include "lib/server_prefork_util.h"
  23
  24 void pfh_daemon_config(const char *daemon_name,
  25                         struct pf_daemon_config *cfg,
  26                         struct pf_daemon_config *default_cfg)
  27 {
  28         int min, max, rate, allow, life;
  29
  30         min = lp_parm_int(GLOBAL_SECTION_SNUM,
  31                                 daemon_name,
  32                                 "prefork_min_children",
  33                                 default_cfg->min_children);
  34         max = lp_parm_int(GLOBAL_SECTION_SNUM,
  35                                 daemon_name,
  36                                 "prefork_max_children",
  37                                 default_cfg->max_children);
  38         rate = lp_parm_int(GLOBAL_SECTION_SNUM,
  39                                 daemon_name,
  40                                 "prefork_spawn_rate",
  41                                 default_cfg->spawn_rate);
  42         allow = lp_parm_int(GLOBAL_SECTION_SNUM,
  43                                 daemon_name,
  44                                 "prefork_max_allowed_clients",
  45                                 default_cfg->max_allowed_clients);
  46         life = lp_parm_int(GLOBAL_SECTION_SNUM,
  47                                 daemon_name,
  48                                 "prefork_child_min_life",
  49                                 default_cfg->child_min_life);
  50
  51         if (max > cfg->max_children && cfg->max_children != 0) {
  52                 cfg->prefork_status |= PFH_NEW_MAX;
  53         }
  54
  55         cfg->min_children = min;
  56         cfg->max_children = max;
  57         cfg->spawn_rate = rate;
  58         cfg->max_allowed_clients = allow;
  59         cfg->child_min_life = life;
  60 }
  61
  62 void pfh_manage_pool(struct tevent_context *ev_ctx,
  63                      struct messaging_context *msg_ctx,
  64                      struct pf_daemon_config *cfg,
  65                      struct prefork_pool *pool)
  66 {
  67         time_t now = time(NULL);
  68         int total, avail;
  69         int ret, n;
  70         bool msg = false;
  71
  72         if ((cfg->prefork_status & PFH_NEW_MAX) &&
  73             !(cfg->prefork_status & PFH_ENOSPC)) {
  74                 ret = prefork_expand_pool(pool, cfg->max_children);
  75                 if (ret == ENOSPC) {
  76                         cfg->prefork_status |= PFH_ENOSPC;
  77                 }
  78                 cfg->prefork_status &= ~PFH_NEW_MAX;
  79         }
  80
  81         total = prefork_count_children(pool, NULL);
  82         avail = prefork_count_allowed_connections(pool);
  83         DEBUG(10, ("(Pre)Stats: children: %d, allowed connections: %d\n",
  84                    total, avail));
  85
  86         if ((total < cfg->max_children) && (avail < cfg->spawn_rate)) {
  87                 n = prefork_add_children(ev_ctx, msg_ctx,
  88                                          pool, cfg->spawn_rate);
  89                 if (n < cfg->spawn_rate) {
  90                         DEBUG(10, ("Attempted to add %d children but only "
  91                                    "%d were actually added!\n",
  92                                    cfg->spawn_rate, n));
  93                 }
  94         } else if ((avail - cfg->min_children) >= cfg->spawn_rate) {
  95                 /* be a little slower in retiring children, to allow for
  96                  * double spikes of traffic to be handled more gracefully */
  97                 n = (cfg->spawn_rate / 2) + 1;
  98                 if (n > cfg->spawn_rate) {
  99                         n = cfg->spawn_rate;
 100                 }
 101                 if ((total - n) < cfg->min_children) {
 102                         n = total - cfg->min_children;
 103                 }
 104                 if (n >= 0) {
 105                         prefork_retire_children(msg_ctx, pool, n,
 106                                                 now - cfg->child_min_life);
 107                 }
 108         }
 109
 110         /* total/avail may have just been changed in the above if/else */
 111         total = prefork_count_children(pool, NULL);
 112         avail = prefork_count_allowed_connections(pool);
 113         if ((total == cfg->max_children) && (avail < cfg->spawn_rate)) {
 114                 n = avail;
 115                 while (avail < cfg->spawn_rate) {
 116                         prefork_increase_allowed_clients(pool,
 117                                                 cfg->max_allowed_clients);
 118                         avail = prefork_count_allowed_connections(pool);
 119                         /* if avail didn't change do not loop forever */
 120                         if (n == avail) break;
 121                         n = avail;
 122                 }
 123                 msg = true;
 124         } else if (avail > total + cfg->spawn_rate) {
 125                 n = avail;
 126                 while (avail > total + cfg->spawn_rate) {
 127                         prefork_decrease_allowed_clients(pool);
 128                         avail = prefork_count_allowed_connections(pool);
 129                         /* if avail didn't change do not loop forever */
 130                         if (n == avail) break;
 131                         n = avail;
 132                 }
 133         }
 134
 135         /* send message to all children when we change maximum allowed
 136          * connections, so that they can decide to start again to listen to
 137          * sockets if they were already topping the number of allowed
 138          * clients. Useful only when we increase allowed clients */
 139         if (msg) {
 140                 prefork_warn_active_children(msg_ctx, pool);
 141         }
 142
 143         DEBUG(10, ("Stats: children: %d, allowed connections: %d\n",
 144                   prefork_count_children(pool, NULL),
 145                   prefork_count_allowed_connections(pool)));
 146 }
 147
 148 void pfh_client_terminated(struct pf_worker_data *pf)
 149 {
 150         if (pf->num_clients >= 0) {
 151                 pf->num_clients--;
 152         } else {
 153                 if (pf->status != PF_WORKER_EXITING) {
 154                         DEBUG(1, ("Invalid num clients, stopping!\n"));
 155                 }
 156                 pf->status = PF_WORKER_EXITING;
 157                 pf->num_clients = -1;
 158         }
 159 }
 160
 161 bool pfh_child_allowed_to_accept(struct pf_worker_data *pf)
 162 {
 163         if (pf->status == PF_WORKER_EXITING ||
 164             pf->status == PF_WORKER_ACCEPTING) {
 165                 return false;
 166         }
 167
 168         return (pf->num_clients < pf->allowed_clients);
 169 }