glibc/debug/backtrace.c

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/* Return backtrace of current program state. Generic version.
Copyright (C) 1998-2013 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <execinfo.h>
#include <signal.h>
#include <frame.h>
#include <sigcontextinfo.h>
#include <ldsodefs.h>
/* This implementation assumes a stack layout that matches the defaults
used by gcc's `__builtin_frame_address' and `__builtin_return_address'
(FP is the frame pointer register):
+-----------------+ +-----------------+
FP -> | previous FP --------> | previous FP ------>...
| | | |
| return address | | return address |
+-----------------+ +-----------------+
*/
/* Get some notion of the current stack. Need not be exactly the top
of the stack, just something somewhere in the current frame. */
#ifndef CURRENT_STACK_FRAME
# define CURRENT_STACK_FRAME ({ char __csf; &__csf; })
#endif
/* By default we assume that the stack grows downward. */
#ifndef INNER_THAN
# define INNER_THAN <
#endif
/* By default assume the `next' pointer in struct layout points to the
next struct layout. */
#ifndef ADVANCE_STACK_FRAME
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# define ADVANCE_STACK_FRAME(next) ((struct layout *) (next))
#endif
/* By default, the frame pointer is just what we get from gcc. */
#ifndef FIRST_FRAME_POINTER
# define FIRST_FRAME_POINTER __builtin_frame_address (0)
#endif
int
__backtrace (array, size)
void **array;
int size;
{
struct layout *current;
void *top_frame;
void *top_stack;
int cnt = 0;
top_frame = FIRST_FRAME_POINTER;
top_stack = CURRENT_STACK_FRAME;
/* We skip the call to this function, it makes no sense to record it. */
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current = ((struct layout *) top_frame);
while (cnt < size)
{
if ((void *) current INNER_THAN top_stack
|| !((void *) current INNER_THAN __libc_stack_end))
/* This means the address is out of range. Note that for the
toplevel we see a frame pointer with value NULL which clearly is
out of range. */
break;
array[cnt++] = current->return_address;
current = ADVANCE_STACK_FRAME (current->next);
}
return cnt;
}
weak_alias (__backtrace, backtrace)
libc_hidden_def (__backtrace)