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			123 lines
		
	
	
		
			3.1 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			123 lines
		
	
	
		
			3.1 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/* Return backtrace of current program state.
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   Copyright (C) 2013-2025 Free Software Foundation, Inc.
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   This file is part of the GNU C Library.
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   The GNU C Library is free software; you can redistribute it and/or
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   modify it under the terms of the GNU Library General Public License as
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   published by the Free Software Foundation; either version 2 of the
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   License, or (at your option) any later version.
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   The GNU C Library is distributed in the hope that it will be useful,
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   but WITHOUT ANY WARRANTY; without even the implied warranty of
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   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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   Library General Public License for more details.
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   You should have received a copy of the GNU Library General Public
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   License along with the GNU C Library; see the file COPYING.LIB.  If
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   not, see <https://www.gnu.org/licenses/>.  */
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#include <execinfo.h>
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#include <stddef.h>
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#include <sysdep.h>
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#include <sys/trap.h>
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#include <backtrace.h>
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#include <unwind-link.h>
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struct layout
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{
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  unsigned long locals[8];
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  unsigned long ins[6];
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  unsigned long next;
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  void *return_address;
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};
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struct trace_arg
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{
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  void **array;
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  struct unwind_link *unwind_link;
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  _Unwind_Word cfa;
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  int cnt;
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  int size;
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};
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static _Unwind_Reason_Code
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backtrace_helper (struct _Unwind_Context *ctx, void *a)
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{
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  struct trace_arg *arg = a;
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  _Unwind_Ptr ip;
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  /* We are first called with address in the __backtrace function.
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     Skip it.  */
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  if (arg->cnt != -1)
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    {
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      ip = UNWIND_LINK_PTR (arg->unwind_link, _Unwind_GetIP) (ctx);
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      arg->array[arg->cnt] = (void *) ip;
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      /* Check whether we make any progress.  */
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      _Unwind_Word cfa
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	= UNWIND_LINK_PTR (arg->unwind_link, _Unwind_GetCFA) (ctx);
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      if (arg->cnt > 0 && arg->array[arg->cnt - 1] == arg->array[arg->cnt]
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	 && cfa == arg->cfa)
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       return _URC_END_OF_STACK;
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      arg->cfa = cfa;
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    }
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  if (++arg->cnt == arg->size)
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    return _URC_END_OF_STACK;
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  return _URC_NO_REASON;
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}
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int
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__backtrace (void **array, int size)
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{
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  int count;
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  struct trace_arg arg =
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    {
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     .array = array,
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     .unwind_link = __libc_unwind_link_get (),
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     .size = size,
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     .cnt = -1,
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    };
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  if (size <= 0)
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    return 0;
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  if (arg.unwind_link == NULL)
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    {
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      struct layout *current;
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      unsigned long fp, i7;
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      asm volatile ("mov %%fp, %0" : "=r"(fp));
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      asm volatile ("mov %%i7, %0" : "=r"(i7));
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      current = (struct layout *) (fp + BACKTRACE_STACK_BIAS);
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      array[0] = (void *) i7;
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      if (size == 1)
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	return 1;
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      backtrace_flush_register_windows();
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      for (count = 1; count < size; count++)
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	{
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	  array[count] = current->return_address;
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	  if (!current->next)
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	    break;
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	  current = (struct layout *) (current->next + BACKTRACE_STACK_BIAS);
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	}
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    }
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  else
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    {
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      UNWIND_LINK_PTR (arg.unwind_link, _Unwind_Backtrace)
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	(backtrace_helper, &arg);
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      /* _Unwind_Backtrace seems to put NULL address above
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	 _start.  Fix it up here.  */
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      if (arg.cnt > 1 && arg.array[arg.cnt - 1] == NULL)
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	--arg.cnt;
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      count = arg.cnt != -1 ? arg.cnt : 0;
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    }
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  return count;
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}
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weak_alias (__backtrace, backtrace)
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libc_hidden_def (__backtrace)
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