src/eventl.c

   1 /*
   2  * Copyright (C) 1995-2005, Index Data ApS
   3  * See the file LICENSE for details.
   4  *
   5  * $Id: eventl.c,v 1.6 2005-01-17 12:53:04 adam Exp $
   6  */
   7
   8 /**
   9  * \file eventl.c
  10  * \brief Implements event loop handling for GFS.
  11  *
  12  * This source implements the main event loop for the Generic Frontend
  13  * Server. It uses select(2).
  14  */
  15
  16 #include <assert.h>
  17 #include <errno.h>
  18 #include <stdio.h>
  19 #include <stdlib.h>
  20 #include <string.h>
  21
  22 #if HAVE_SYS_TYPES_H
  23 #include <sys/types.h>
  24 #endif
  25 #if HAVE_SYS_TIME_H
  26 #include <sys/time.h>
  27 #endif
  28 #ifdef WIN32
  29 #include <winsock.h>
  30 #endif
  31 #if HAVE_UNISTD_H
  32 #include <unistd.h>
  33 #endif
  34 #if HAVE_SYS_SELECT_H
  35 #include <sys/select.h>
  36 #endif
  37
  38 #include <yaz/yconfig.h>
  39 #include <yaz/log.h>
  40 #include <yaz/comstack.h>
  41 #include <yaz/xmalloc.h>
  42 #include "eventl.h"
  43 #include "session.h"
  44 #include <yaz/statserv.h>
  45
  46 #if YAZ_GNU_THREADS
  47 #include <pth.h>
  48 #define YAZ_EV_SELECT pth_select
  49 #endif
  50
  51 #ifndef YAZ_EV_SELECT
  52 #define YAZ_EV_SELECT select
  53 #endif
  54
  55 static int log_level=0;
  56 static int log_level_initialized=0;
  57
  58 IOCHAN iochan_create(int fd, IOC_CALLBACK cb, int flags)
  59 {
  60     IOCHAN new_iochan;
  61
  62     if (!log_level_initialized)
  63     {
  64         log_level=yaz_log_module_level("eventl");
  65         log_level_initialized=1;
  66     }
  67
  68     if (!(new_iochan = (IOCHAN)xmalloc(sizeof(*new_iochan))))
  69         return 0;
  70     new_iochan->destroyed = 0;
  71     new_iochan->fd = fd;
  72     new_iochan->flags = flags;
  73     new_iochan->fun = cb;
  74     new_iochan->force_event = 0;
  75     new_iochan->last_event = new_iochan->max_idle = 0;
  76     new_iochan->next = NULL;
  77     return new_iochan;
  78 }
  79
  80 int event_loop(IOCHAN *iochans)
  81 {
  82     do /* loop as long as there are active associations to process */
  83     {
  84         IOCHAN p, nextp;
  85         fd_set in, out, except;
  86         int res, max;
  87         static struct timeval to;
  88         time_t now = time(0);
  89
  90         if (statserv_must_terminate())
  91         {
  92             for (p = *iochans; p; p = p->next)
  93                 p->force_event = EVENT_TIMEOUT;
  94         }
  95         FD_ZERO(&in);
  96         FD_ZERO(&out);
  97         FD_ZERO(&except);
  98         to.tv_sec = 3600;
  99         to.tv_usec = 0;
 100         max = 0;
 101         for (p = *iochans; p; p = p->next)
 102         {
 103             time_t w, ftime;
 104             yaz_log(log_level, "fd=%d flags=%d force_event=%d",
 105                     p->fd, p->flags, p->force_event);
 106             if (p->force_event)
 107                 to.tv_sec = 0;          /* polling select */
 108             if (p->flags & EVENT_INPUT)
 109                 FD_SET(p->fd, &in);
 110             if (p->flags & EVENT_OUTPUT)
 111                 FD_SET(p->fd, &out);
 112             if (p->flags & EVENT_EXCEPT)
 113                 FD_SET(p->fd, &except);
 114             if (p->fd > max)
 115                 max = p->fd;
 116             if (p->max_idle && p->last_event)
 117             {
 118                 ftime = p->last_event + p->max_idle;
 119                 if (ftime < now)
 120                     w = p->max_idle;
 121                 else
 122                     w = ftime - now;
 123                 if (w < to.tv_sec)
 124                     to.tv_sec = w;
 125             }
 126         }
 127         yaz_log(log_level, "select start %ld", (long) to.tv_sec);
 128         res = YAZ_EV_SELECT(max + 1, &in, &out, &except, &to);
 129         yaz_log(log_level, "select end");
 130         if (res < 0)
 131         {
 132             if (yaz_errno() == EINTR)
 133             {
 134                 if (statserv_must_terminate())
 135                 {
 136                     for (p = *iochans; p; p = p->next)
 137                         p->force_event = EVENT_TIMEOUT;
 138                 }
 139                 continue;
 140             }
 141             else
 142             {
 143                 /* Destroy the first member in the chain, and try again */
 144                 association *assoc = (association *)iochan_getdata(*iochans);
 145                 COMSTACK conn = assoc->client_link;
 146
 147                 cs_close(conn);
 148                 destroy_association(assoc);
 149                 iochan_destroy(*iochans);
 150                 yaz_log(log_level, "error select, destroying iochan %p",
 151                         *iochans);
 152             }
 153         }
 154         now = time(0);
 155         for (p = *iochans; p; p = p->next)
 156         {
 157             int force_event = p->force_event;
 158
 159             p->force_event = 0;
 160             if (!p->destroyed && (FD_ISSET(p->fd, &in) ||
 161                 force_event == EVENT_INPUT))
 162             {
 163                 p->last_event = now;
 164                 (*p->fun)(p, EVENT_INPUT);
 165             }
 166             if (!p->destroyed && (FD_ISSET(p->fd, &out) ||
 167                 force_event == EVENT_OUTPUT))
 168             {
 169                 p->last_event = now;
 170                 (*p->fun)(p, EVENT_OUTPUT);
 171             }
 172             if (!p->destroyed && (FD_ISSET(p->fd, &except) ||
 173                 force_event == EVENT_EXCEPT))
 174             {
 175                 p->last_event = now;
 176                 (*p->fun)(p, EVENT_EXCEPT);
 177             }
 178             if (!p->destroyed && ((p->max_idle && now - p->last_event >=
 179                 p->max_idle) || force_event == EVENT_TIMEOUT))
 180             {
 181                 p->last_event = now;
 182                 (*p->fun)(p, EVENT_TIMEOUT);
 183             }
 184         }
 185         for (p = *iochans; p; p = nextp)
 186         {
 187             nextp = p->next;
 188
 189             if (p->destroyed)
 190             {
 191                 IOCHAN tmp = p, pr;
 192
 193                 /* We need to inform the threadlist that this channel has been destroyed */
 194                 statserv_remove(p);
 195
 196                 /* Now reset the pointers */
 197                 if (p == *iochans)
 198                     *iochans = p->next;
 199                 else
 200                 {
 201                     for (pr = *iochans; pr; pr = pr->next)
 202                         if (pr->next == p)
 203                             break;
 204                     assert(pr); /* grave error if it weren't there */
 205                     pr->next = p->next;
 206                 }
 207                 if (nextp == p)
 208                     nextp = p->next;
 209                 xfree(tmp);
 210             }
 211         }
 212     }
 213     while (*iochans);
 214     return 0;
 215 }