include/register-atfork.h

   1 /* Internal pthread_atfork definitions.
   2    Copyright (C) 2021-2022 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   uint64_t id;
  30 };
  31
  32 /* Function to call to unregister fork handlers.  */
  33 extern void __unregister_atfork (void *dso_handle) attribute_hidden;
  34 #define UNREGISTER_ATFORK(dso_handle) __unregister_atfork (dso_handle)
  35
  36 enum __run_fork_handler_type
  37 {
  38   atfork_run_prepare,
  39   atfork_run_child,
  40   atfork_run_parent
  41 };
  42
  43 /* Run the atfork prepare handlers in the reverse order of registration and
  44    return the ID of the last registered handler.  If DO_LOCKING is true, the
  45    internal lock is held locked upon return.  */
  46 extern uint64_t __run_prefork_handlers (_Bool do_locking) attribute_hidden;
  47
  48 /* Given a handler type (parent or child), run all the atfork handlers in
  49    the order of registration up to and including the handler with id equal
  50    to LASTRUN.  If DO_LOCKING is true, the internal lock is unlocked prior
  51    to return.  */
  52 extern void __run_postfork_handlers (enum __run_fork_handler_type who,
  53                                      _Bool do_locking,
  54                                      uint64_t lastrun) 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