1/* _Fork implementation. Linux version.
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#include <arch-fork.h>
20#include <pthreadP.h>
21
22/* Pointer to the fork generation counter in the thread library. */
23extern unsigned long int *__fork_generation_pointer attribute_hidden;
24
25pid_t
26_Fork (void)
27{
28 pid_t pid = arch_fork (&THREAD_SELF->tid);
29 if (pid == 0)
30 {
31 struct pthread *self = THREAD_SELF;
32
33 /* Initialize the robust mutex list setting in the kernel which has
34 been reset during the fork. We do not check for errors because if
35 it fails here, it must have failed at process startup as well and
36 nobody could have used robust mutexes.
37 Before we do that, we have to clear the list of robust mutexes
38 because we do not inherit ownership of mutexes from the parent.
39 We do not have to set self->robust_head.futex_offset since we do
40 inherit the correct value from the parent. We do not need to clear
41 the pending operation because it must have been zero when fork was
42 called. */
43#if __PTHREAD_MUTEX_HAVE_PREV
44 self->robust_prev = &self->robust_head;
45#endif
46 self->robust_head.list = &self->robust_head;
47 INTERNAL_SYSCALL_CALL (set_robust_list, &self->robust_head,
48 sizeof (struct robust_list_head));
49 }
50 return pid;
51}
52libc_hidden_def (_Fork)
53