1  /* Copyright (C) 1999-2023 Free Software Foundation, Inc.
       2  
       3     NOTE: This source is derived from an old version taken from the GNU C
       4     Library (glibc).
       5  
       6  This file is part of GCC.
       7  
       8  GCC is free software; you can redistribute it and/or modify it under
       9  the terms of the GNU General Public License as published by the Free
      10  Software Foundation; either version 3, or (at your option) any later
      11  version.
      12  
      13  GCC is distributed in the hope that it will be useful, but WITHOUT ANY
      14  WARRANTY; without even the implied warranty of MERCHANTABILITY or
      15  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
      16  for more details.
      17  
      18  Under Section 7 of GPL version 3, you are granted additional
      19  permissions described in the GCC Runtime Library Exception, version
      20  3.1, as published by the Free Software Foundation.
      21  
      22  You should have received a copy of the GNU General Public License and
      23  a copy of the GCC Runtime Library Exception along with this program;
      24  see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
      25  <http://www.gnu.org/licenses/>.  */
      26  
      27  #include <assert.h>
      28  #include <stdlib.h>
      29  #include "exit.h"
      30  
      31  
      32  static boolean_t
      33  catomic_compare_and_exchange_bool_acq (long *mem, long newval, long oldval)
      34  {
      35    return ! __atomic_compare_exchange (mem, &oldval, &newval, 0,
      36  				      __ATOMIC_ACQUIRE, __ATOMIC_ACQUIRE);
      37  }
      38  
      39  /* If D is non-NULL, call all functions registered with `__cxa_atexit'
      40     with the same dso handle.  Otherwise, if D is NULL, call all of the
      41     registered handlers.  */
      42  void
      43  __cxa_finalize (void *d)
      44  {
      45    struct exit_function_list *funcs;
      46  
      47   restart:
      48    for (funcs = __exit_funcs; funcs; funcs = funcs->next)
      49      {
      50        struct exit_function *f;
      51  
      52        for (f = &funcs->fns[funcs->idx - 1]; f >= &funcs->fns[0]; --f)
      53  	{
      54  	  void (*cxafn) (void *arg, int status);
      55  	  void *cxaarg;
      56  
      57  	  if ((d == NULL || d == f->func.cxa.dso_handle)
      58  	      /* We don't want to run this cleanup more than once.  */
      59  	      && (cxafn = f->func.cxa.fn,
      60  		  cxaarg = f->func.cxa.arg,
      61  		  ! catomic_compare_and_exchange_bool_acq (&f->flavor, ef_free,
      62  							   ef_cxa)))
      63  	    {
      64  	      uint64_t check = __new_exitfn_called;
      65  
      66  #ifdef PTR_DEMANGLE
      67  	      PTR_DEMANGLE (cxafn);
      68  #endif
      69  	      cxafn (cxaarg, 0);
      70  
      71  	      /* It is possible that that last exit function registered
      72  		 more exit functions.  Start the loop over.  */
      73  	      if (__builtin_expect (check != __new_exitfn_called, 0))
      74  		goto restart;
      75  	    }
      76  	}
      77      }
      78  
      79    /* Remove the registered fork handlers.  We do not have to
      80       unregister anything if the program is going to terminate anyway.  */
      81  #ifdef UNREGISTER_ATFORK
      82    if (d != NULL)
      83      UNREGISTER_ATFORK (d);
      84  #endif
      85  }