/* 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 # 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. */ 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)