src/heur-ac.h

   1 /* Detecting stack overflow.  Version for platforms which supply the
   2    fault address and have sigsegv_get_vma.
   3    Copyright (C) 2003  Bruno Haible <bruno@clisp.org>
   4
   5    This program is free software; you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 2, or (at your option)
   8    any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program; if not, write to the Free Software Foundation,
  17    Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
  18
  19 static unsigned long stack_top = 0;
  20
  21 static int
  22 remember_stack_top (void *some_variable_on_stack)
  23 {
  24   struct vma_struct vma;
  25
  26   if (stack_top)
  27     return 0;
  28
  29   /* Needs to be retrieved once only.  */
  30   if (sigsegv_get_vma ((unsigned long) some_variable_on_stack, &vma) >= 0)
  31     {
  32       stack_top = vma.end - 1;
  33       return 0;
  34     }
  35   else
  36     return -1;
  37 }
  38
  39 #define IS_STACK_OVERFLOW \
  40   is_stk_overflow ((unsigned long) SIGSEGV_FAULT_ADDRESS)
  41
  42 static int
  43 is_stk_overflow (unsigned long addr)
  44 {
  45   struct vma_struct vma;
  46
  47   if (sigsegv_get_vma (stack_top, &vma) < 0)
  48     return 0;
  49
  50 #ifdef __ia64
  51   return (addr >= vma.prev_end && addr <= vma.end - 1);
  52 #else
  53 #if STACK_DIRECTION < 0
  54   return (addr >= vma.start
  55           ? (addr <= vma.end - 1)
  56           : (vma.start - addr < (vma.start - vma.prev_end) / 2));
  57 #else
  58   return (addr <= vma.end - 1
  59           ? (addr >= vma.start)
  60           : (addr - vma.end < (vma.next_start - vma.end) / 2));
  61 #endif
  62 #endif
  63 }
  64