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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) 2013-2023 Free Software Foundation, Inc.
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|    This file is part of the GNU C Library.
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| 
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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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| 
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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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| 
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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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| 
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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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| 
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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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| 
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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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| 
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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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| 
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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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| 
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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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| 
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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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| 
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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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| 
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|   if (size <= 0)
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|     return 0;
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| 
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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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| 
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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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| 
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|       array[0] = (void *) i7;
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| 
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|       if (size == 1)
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| 	return 1;
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| 
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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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| 
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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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