1  /* Copyright (C) 1991-2023 Free Software Foundation, Inc.
       2     This file is part of the GNU C Library.
       3  
       4     The GNU C Library is free software; you can redistribute it and/or
       5     modify it under the terms of the GNU Lesser General Public
       6     License as published by the Free Software Foundation; either
       7     version 2.1 of the License, or (at your option) any later version.
       8  
       9     The GNU C Library is distributed in the hope that it will be useful,
      10     but WITHOUT ANY WARRANTY; without even the implied warranty of
      11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      12     Lesser General Public License for more details.
      13  
      14     You should have received a copy of the GNU Lesser General Public
      15     License along with the GNU C Library; if not, see
      16     <https://www.gnu.org/licenses/>.  */
      17  
      18  #include <assert.h>
      19  #include <stdlib.h>
      20  #include "exit.h"
      21  #include <pointer_guard.h>
      22  
      23  /* Register a function to be called by exit.  */
      24  int
      25  __on_exit (void (*func) (int status, void *arg), void *arg)
      26  {
      27    struct exit_function *new;
      28  
      29    /* As a QoI issue we detect NULL early with an assertion instead
      30       of a SIGSEGV at program exit when the handler is run (bug 20544).  */
      31    assert (func != NULL);
      32  
      33     __libc_lock_lock (__exit_funcs_lock);
      34    new = __new_exitfn (&__exit_funcs);
      35  
      36    if (new == NULL)
      37      {
      38        __libc_lock_unlock (__exit_funcs_lock);
      39        return -1;
      40      }
      41  
      42    PTR_MANGLE (func);
      43    new->func.on.fn = func;
      44    new->func.on.arg = arg;
      45    new->flavor = ef_on;
      46    __libc_lock_unlock (__exit_funcs_lock);
      47    return 0;
      48  }
      49  weak_alias (__on_exit, on_exit)