mmalloc/keys.c

   1 /* Access for application keys in mmap'd malloc managed region.
   2    Copyright 1992 Free Software Foundation, Inc.
   3
   4    Contributed by Fred Fish at Cygnus Support.   fnf@cygnus.com
   5
   6 This file is part of the GNU C Library.
   7
   8 The GNU C Library is free software; you can redistribute it and/or
   9 modify it under the terms of the GNU Library General Public License as
  10 published by the Free Software Foundation; either version 2 of the
  11 License, or (at your option) any later version.
  12
  13 The GNU C Library is distributed in the hope that it will be useful,
  14 but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16 Library General Public License for more details.
  17
  18 You should have received a copy of the GNU Library General Public
  19 License along with the GNU C Library; see the file COPYING.LIB.  If
  20 not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  21 Boston, MA 02111-1307, USA.  */
  22
  23 /* This module provides access to some keys that the application can use to
  24    provide persistent access to locations in the mapped memory section.
  25    The intent is that these keys are to be used sparingly as sort of
  26    persistent global variables which the application can use to reinitialize
  27    access to data in the mapped region.
  28
  29    For the moment, these keys are simply stored in the malloc descriptor
  30    itself, in an array of fixed length.  This should be fixed so that there
  31    can be an unlimited number of keys, possibly using a multilevel access
  32    scheme of some sort. */
  33
  34 #include "mmprivate.h"
  35
  36 int
  37 mmalloc_setkey (md, keynum, key)
  38   PTR md;
  39   int keynum;
  40   PTR key;
  41 {
  42   struct mdesc *mdp = (struct mdesc *) md;
  43   int result = 0;
  44
  45   if ((mdp != NULL) && (keynum >= 0) && (keynum < MMALLOC_KEYS))
  46     {
  47       mdp -> keys [keynum] = key;
  48       result++;
  49     }
  50   return (result);
  51 }
  52
  53 PTR
  54 mmalloc_getkey (md, keynum)
  55   PTR md;
  56   int keynum;
  57 {
  58   struct mdesc *mdp = (struct mdesc *) md;
  59   PTR keyval = NULL;
  60
  61   if ((mdp != NULL) && (keynum >= 0) && (keynum < MMALLOC_KEYS))
  62     {
  63       keyval = mdp -> keys [keynum];
  64     }
  65   return (keyval);
  66 }