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 1.9 2005-06-25 15:46:04 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, int chan_id)
  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     new_iochan->chan_id = chan_id;
  78     return new_iochan;
  79 }
  80
  81 int event_loop(IOCHAN *iochans)
  82 {
  83     do /* loop as long as there are active associations to process */
  84     {
  85         IOCHAN p, nextp;
  86         fd_set in, out, except;
  87         int res, max;
  88         static struct timeval to;
  89         time_t now = time(0);
  90
  91         if (statserv_must_terminate())
  92         {
  93             for (p = *iochans; p; p = p->next)
  94                 p->force_event = EVENT_TIMEOUT;
  95         }
  96         FD_ZERO(&in);
  97         FD_ZERO(&out);
  98         FD_ZERO(&except);
  99         to.tv_sec = 3600;
 100         to.tv_usec = 0;
 101         max = 0;
 102         for (p = *iochans; p; p = p->next)
 103         {
 104             time_t w, ftime;
 105             yaz_log(log_level, "fd=%d flags=%d force_event=%d",
 106                     p->fd, p->flags, p->force_event);
 107             if (p->force_event)
 108                 to.tv_sec = 0;          /* polling select */
 109             if (p->flags & EVENT_INPUT)
 110                 FD_SET(p->fd, &in);
 111             if (p->flags & EVENT_OUTPUT)
 112                 FD_SET(p->fd, &out);
 113             if (p->flags & EVENT_EXCEPT)
 114                 FD_SET(p->fd, &except);
 115             if (p->fd > max)
 116                 max = p->fd;
 117             if (p->max_idle && p->last_event)
 118             {
 119                 ftime = p->last_event + p->max_idle;
 120                 if (ftime < now)
 121                     w = p->max_idle;
 122                 else
 123                     w = ftime - now;
 124                 if (w < to.tv_sec)
 125                     to.tv_sec = w;
 126             }
 127         }
 128         yaz_log(log_level, "select start %ld", (long) to.tv_sec);
 129         res = YAZ_EV_SELECT(max + 1, &in, &out, &except, &to);
 130         yaz_log(log_level, "select end");
 131         if (res < 0)
 132         {
 133             if (yaz_errno() == EINTR)
 134             {
 135                 if (statserv_must_terminate())
 136                 {
 137                     for (p = *iochans; p; p = p->next)
 138                         p->force_event = EVENT_TIMEOUT;
 139                 }
 140                 continue;
 141             }
 142             else
 143             {
 144                 /* Destroy the first member in the chain, and try again */
 145                 association *assoc = (association *)iochan_getdata(*iochans);
 146                 COMSTACK conn = assoc->client_link;
 147
 148                 cs_close(conn);
 149                 destroy_association(assoc);
 150                 iochan_destroy(*iochans);
 151                 yaz_log(log_level, "error select, destroying iochan %p",
 152                         *iochans);
 153             }
 154         }
 155         now = time(0);
 156         for (p = *iochans; p; p = p->next)
 157         {
 158             int force_event = p->force_event;
 159
 160             p->force_event = 0;
 161             if (!p->destroyed && (FD_ISSET(p->fd, &in) ||
 162                 force_event == EVENT_INPUT))
 163             {
 164                 p->last_event = now;
 165                 (*p->fun)(p, EVENT_INPUT);
 166             }
 167             if (!p->destroyed && (FD_ISSET(p->fd, &out) ||
 168                 force_event == EVENT_OUTPUT))
 169             {
 170                 p->last_event = now;
 171                 (*p->fun)(p, EVENT_OUTPUT);
 172             }
 173             if (!p->destroyed && (FD_ISSET(p->fd, &except) ||
 174                 force_event == EVENT_EXCEPT))
 175             {
 176                 p->last_event = now;
 177                 (*p->fun)(p, EVENT_EXCEPT);
 178             }
 179             if (!p->destroyed && ((p->max_idle && now - p->last_event >=
 180                 p->max_idle) || force_event == EVENT_TIMEOUT))
 181             {
 182                 p->last_event = now;
 183                 (*p->fun)(p, EVENT_TIMEOUT);
 184             }
 185         }
 186         for (p = *iochans; p; p = nextp)
 187         {
 188             nextp = p->next;
 189
 190             if (p->destroyed)
 191             {
 192                 IOCHAN tmp = p, pr;
 193
 194                 /* We need to inform the threadlist that this channel has been destroyed */
 195                 statserv_remove(p);
 196
 197                 /* Now reset the pointers */
 198                 if (p == *iochans)
 199                     *iochans = p->next;
 200                 else
 201                 {
 202                     for (pr = *iochans; pr; pr = pr->next)
 203                         if (pr->next == p)
 204                             break;
 205                     assert(pr); /* grave error if it weren't there */
 206                     pr->next = p->next;
 207                 }
 208                 if (nextp == p)
 209                     nextp = p->next;
 210                 xfree(tmp);
 211             }
 212         }
 213     }
 214     while (*iochans);
 215     return 0;
 216 }
 217 /*
 218  * Local variables:
 219  * c-basic-offset: 4
 220  * indent-tabs-mode: nil
 221  * End:
 222  * vim: shiftwidth=4 tabstop=8 expandtab
 223  */
 224