src/stackvma-simple.c

   1 /* Determine the virtual memory area of a given address.
   2    Copyright (C) 2006  Bruno Haible <bruno@clisp.org>
   3
   4    This program is free software; you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 2, or (at your option)
   7    any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program; if not, write to the Free Software Foundation,
  16    Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
  17
  18 /* This file contains the proximity test function for the simple cases, where
  19    the OS has an API for enumerating the mapped ranges of virtual memory.  */
  20
  21 #if STACK_DIRECTION < 0
  22
  23 /* Info about the gap between this VMA and the previous one.
  24    addr must be < vma->start.  */
  25 static int
  26 simple_is_near_this (unsigned long addr, struct vma_struct *vma)
  27 {
  28   return (vma->start - addr <= (vma->start - vma->prev_end) / 2);
  29 }
  30
  31 #endif
  32 #if STACK_DIRECTION > 0
  33
  34 /* Info about the gap between this VMA and the next one.
  35    addr must be > vma->end - 1.  */
  36 static int
  37 simple_is_near_this (unsigned long addr, struct vma_struct *vma)
  38 {
  39   return (addr - vma->end < (vma->next_start - vma->end) / 2);
  40 }
  41
  42 #endif