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. */
22extern unsigned long int __fork_generation attribute_hidden;
23
24/* Pointer to the fork generation counter in the thread library. */
25extern unsigned long int *__fork_generation_pointer attribute_hidden;
26
27/* Elements of the fork handler lists. */
28struct 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. */
37extern void __unregister_atfork (void *dso_handle) attribute_hidden;
38#define UNREGISTER_ATFORK(dso_handle) __unregister_atfork (dso_handle)
39
40enum __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. */
58extern 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. */
62extern int __register_atfork (void (*__prepare) (void),
63 void (*__parent) (void),
64 void (*__child) (void),
65 void *dso_handle);
66libc_hidden_proto (__register_atfork)
67