contrib/sendmail-8.13.4/sendmail/shmticklib.c

   1 /*
   2  * Copyright (c) 1999-2000 Sendmail, Inc. and its suppliers.
   3  *      All rights reserved.
   4  *
   5  * By using this file, you agree to the terms and conditions set
   6  * forth in the LICENSE file which can be found at the top level of
   7  * the sendmail distribution.
   8  *
   9  * Contributed by Exactis.com, Inc.
  10  *
  11  */
  12
  13 #include <sm/gen.h>
  14 SM_RCSID("@(#)$Id: shmticklib.c,v 8.14 2001/09/11 04:05:16 gshapiro Exp $")
  15
  16 #if _FFR_SHM_STATUS
  17 # include <sys/types.h>
  18 # include <sys/ipc.h>
  19 # include <sys/shm.h>
  20
  21 # include "statusd_shm.h"
  22
  23 /*
  24 **  SHMTICK -- increment a shared memory variable
  25 **
  26 **      Parameters:
  27 **              inc_me -- identity of shared memory segment
  28 **              what -- which variable to increment
  29 **
  30 **      Returns:
  31 **              none
  32 */
  33
  34 void
  35 shmtick(inc_me, what)
  36         int inc_me;
  37         int what;
  38 {
  39         static int shmid = -1;
  40         static STATUSD_SHM *sp = (STATUSD_SHM *)-1;
  41         static unsigned int cookie = 0;
  42
  43         if (shmid < 0)
  44         {
  45                 int size = sizeof(STATUSD_SHM);
  46
  47                 shmid = shmget(STATUSD_SHM_KEY, size, 0);
  48                 if (shmid < 0)
  49                         return;
  50         }
  51         if ((unsigned long *) sp == (unsigned long *)-1)
  52         {
  53                 sp = (STATUSD_SHM *) shmat(shmid, NULL, 0);
  54                 if ((unsigned long *) sp == (unsigned long *) -1)
  55                         return;
  56         }
  57         if (sp->magic != STATUSD_MAGIC)
  58         {
  59                 /*
  60                 **  possible race condition, wait for
  61                 **  statusd to initialize.
  62                 */
  63
  64                 return;
  65         }
  66         if (what >= STATUSD_LONGS)
  67                 what = STATUSD_LONGS - 1;
  68         if (inc_me >= STATUSD_LONGS)
  69                 inc_me = STATUSD_LONGS - 1;
  70
  71         if (sp->ul[STATUSD_COOKIE] != cookie)
  72         {
  73                 cookie = sp->ul[STATUSD_COOKIE];
  74                 ++(sp->ul[inc_me]);
  75         }
  76         ++(sp->ul[what]);
  77 }
  78 #endif /* _FFR_SHM_STATUS */