debug/backtrace.c

   1 /* Return backtrace of current program state.  Generic version.
   2    Copyright (C) 1998, 2000, 2002, 2004, 2005 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 <signal.h>
  23 #include <frame.h>
  24 #include <sigcontextinfo.h>
  25 #include <bp-checks.h>
  26 #include <ldsodefs.h>
  27
  28 /* This implementation assumes a stack layout that matches the defaults
  29    used by gcc's `__builtin_frame_address' and `__builtin_return_address'
  30    (FP is the frame pointer register):
  31
  32           +-----------------+     +-----------------+
  33     FP -> | previous FP --------> | previous FP ------>...
  34           |                 |     |                 |
  35           | return address  |     | return address  |
  36           +-----------------+     +-----------------+
  37
  38   */
  39
  40 /* Get some notion of the current stack.  Need not be exactly the top
  41    of the stack, just something somewhere in the current frame.  */
  42 #ifndef CURRENT_STACK_FRAME
  43 # define CURRENT_STACK_FRAME  ({ char __csf; &__csf; })
  44 #endif
  45
  46 /* By default we assume that the stack grows downward.  */
  47 #ifndef INNER_THAN
  48 # define INNER_THAN <
  49 #endif
  50
  51 /* By default assume the `next' pointer in struct layout points to the
  52    next struct layout.  */
  53 #ifndef ADVANCE_STACK_FRAME
  54 # define ADVANCE_STACK_FRAME(next) BOUNDED_1 ((struct layout *) (next))
  55 #endif
  56
  57 /* By default, the frame pointer is just what we get from gcc.  */
  58 #ifndef FIRST_FRAME_POINTER
  59 # define FIRST_FRAME_POINTER  __builtin_frame_address (0)
  60 #endif
  61
  62 int
  63 __backtrace (array, size)
  64      void **array;
  65      int size;
  66 {
  67   struct layout *current;
  68   void *__unbounded top_frame;
  69   void *__unbounded top_stack;
  70   int cnt = 0;
  71
  72   top_frame = FIRST_FRAME_POINTER;
  73   top_stack = CURRENT_STACK_FRAME;
  74
  75   /* We skip the call to this function, it makes no sense to record it.  */
  76   current = BOUNDED_1 ((struct layout *) top_frame);
  77   while (cnt < size)
  78     {
  79       if ((void *) current INNER_THAN top_stack
  80           || !((void *) current INNER_THAN __libc_stack_end))
  81        /* This means the address is out of range.  Note that for the
  82           toplevel we see a frame pointer with value NULL which clearly is
  83           out of range.  */
  84         break;
  85
  86       array[cnt++] = current->return_address;
  87
  88       current = ADVANCE_STACK_FRAME (current->next);
  89     }
  90
  91   return cnt;
  92 }
  93 weak_alias (__backtrace, backtrace)
  94 libc_hidden_def (__backtrace)