sysdeps/i386/backtrace.c

   1 /* Return backtrace of current program state.
   2    Copyright (C) 1998, 2000 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, write to the Free
  18    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19    02111-1307 USA.  */
  20
  21 #include <execinfo.h>
  22 #include <bp-checks.h>
  23
  24
  25 /* This is a global variable set at program start time.  It marks the
  26    highest used stack address.  */
  27 extern void *__libc_stack_end;
  28
  29
  30 /* This is the stack alyout we see with every stack frame.
  31
  32             +-----------------+        +-----------------+
  33     %ebp -> | %ebp last frame--------> | %ebp last frame--->...
  34             |                 |        |                 |
  35             | return address  |        | return address  |
  36             +-----------------+        +-----------------+
  37 */
  38 struct layout
  39 {
  40   struct layout *__unbounded next;
  41   void *__unbounded return_address;
  42 };
  43
  44 int
  45 __backtrace (array, size)
  46      void **array;
  47      int size;
  48 {
  49   /* We assume that all the code is generated with frame pointers set.  */
  50   register void *ebp __asm__ ("ebp");
  51   register void *esp __asm__ ("esp");
  52   struct layout *current;
  53   int cnt = 0;
  54
  55   /* We skip the call to this function, it makes no sense to record it.  */
  56   current = BOUNDED_1 ((struct layout *) ebp);
  57   while (cnt < size)
  58     {
  59       if ((void *) current < esp || (void *) current > __libc_stack_end)
  60         /* This means the address is out of range.  Note that for the
  61            toplevel we see a frame pointer with value NULL which clearly is
  62            out of range.  */
  63         break;
  64
  65       array[cnt++] = current->return_address;
  66
  67       current = current->next;
  68     }
  69
  70   return cnt;
  71 }
  72 weak_alias (__backtrace, backtrace)