include/register-atfork.h

   1 /* Internal pthread_atfork definitions.
   2    Copyright (C) 2021 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #ifndef _REGISTER_ATFORK_H
  20 #define _REGISTER_ATFORK_H
  21
  22 /* Elements of the fork handler lists.  */
  23 struct fork_handler
  24 {
  25   void (*prepare_handler) (void);
  26   void (*parent_handler) (void);
  27   void (*child_handler) (void);
  28   void *dso_handle;
  29 };
  30
  31 /* Function to call to unregister fork handlers.  */
  32 extern void __unregister_atfork (void *dso_handle) attribute_hidden;
  33 #define UNREGISTER_ATFORK(dso_handle) __unregister_atfork (dso_handle)
  34
  35 enum __run_fork_handler_type
  36 {
  37   atfork_run_prepare,
  38   atfork_run_child,
  39   atfork_run_parent
  40 };
  41
  42 /* Run the atfork handlers and lock/unlock the internal lock depending
  43    of the WHO argument:
  44
  45    - atfork_run_prepare: run all the PREPARE_HANDLER in reverse order of
  46                          insertion and locks the internal lock.
  47    - atfork_run_child: run all the CHILD_HANDLER and unlocks the internal
  48                        lock.
  49    - atfork_run_parent: run all the PARENT_HANDLER and unlocks the internal
  50                         lock.
  51
  52    Perform locking only if DO_LOCKING.  */
  53 extern void __run_fork_handlers (enum __run_fork_handler_type who,
  54                                  _Bool do_locking) attribute_hidden;
  55
  56 /* C library side function to register new fork handlers.  */
  57 extern int __register_atfork (void (*__prepare) (void),
  58                               void (*__parent) (void),
  59                               void (*__child) (void),
  60                               void *dso_handle);
  61 libc_hidden_proto (__register_atfork)
  62
  63 #endif