stdlib/on_exit.c

   1 /* Copyright (C) 1991-2022 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)