sysdeps/nptl/fork.h

   1 /* Copyright (C) 2002-2020 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
   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 #include <lowlevellock.h>
  20
  21 /* The fork generation counter, defined in libpthread.  */
  22 extern unsigned long int __fork_generation attribute_hidden;
  23
  24 /* Pointer to the fork generation counter in the thread library.  */
  25 extern unsigned long int *__fork_generation_pointer attribute_hidden;
  26
  27 /* Elements of the fork handler lists.  */
  28 struct fork_handler
  29 {
  30   void (*prepare_handler) (void);
  31   void (*parent_handler) (void);
  32   void (*child_handler) (void);
  33   void *dso_handle;
  34 };
  35
  36 /* Function to call to unregister fork handlers.  */
  37 extern void __unregister_atfork (void *dso_handle) attribute_hidden;
  38 #define UNREGISTER_ATFORK(dso_handle) __unregister_atfork (dso_handle)
  39
  40 enum __run_fork_handler_type
  41 {
  42   atfork_run_prepare,
  43   atfork_run_child,
  44   atfork_run_parent
  45 };
  46
  47 /* Run the atfork handlers and lock/unlock the internal lock depending
  48    of the WHO argument:
  49
  50    - atfork_run_prepare: run all the PREPARE_HANDLER in reverse order of
  51                          insertion and locks the internal lock.
  52    - atfork_run_child: run all the CHILD_HANDLER and unlocks the internal
  53                        lock.
  54    - atfork_run_parent: run all the PARENT_HANDLER and unlocks the internal
  55                         lock.
  56
  57    Perform locking only if DO_LOCKING.  */
  58 extern void __run_fork_handlers (enum __run_fork_handler_type who,
  59                                  _Bool do_locking) attribute_hidden;
  60
  61 /* C library side function to register new fork handlers.  */
  62 extern int __register_atfork (void (*__prepare) (void),
  63                               void (*__parent) (void),
  64                               void (*__child) (void),
  65                               void *dso_handle);
  66 libc_hidden_proto (__register_atfork)