1 /*
2 * Copyright (C) 2008 The Android Open Source Project
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * * Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * * Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in
12 * the documentation and/or other materials provided with the
13 * distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <unistd.h>
30 #include <sys/syscall.h>
31
32 #include "pthread_internal.h"
33
34 #define FORK_FLAGS (CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID | SIGCHLD)
35
fork()36 int fork() {
37 __bionic_atfork_run_prepare();
38
39 pthread_internal_t* self = __get_thread();
40
41 // Remember the parent pid and invalidate the cached value while we fork.
42 pid_t parent_pid = self->invalidate_cached_pid();
43
44 #if defined(__x86_64__) // sys_clone's last two arguments are flipped on x86-64.
45 int result = syscall(__NR_clone, FORK_FLAGS, NULL, NULL, &(self->tid), NULL);
46 #else
47 int result = syscall(__NR_clone, FORK_FLAGS, NULL, NULL, NULL, &(self->tid));
48 #endif
49 if (result == 0) {
50 self->set_cached_pid(gettid());
51 __bionic_atfork_run_child();
52 } else {
53 self->set_cached_pid(parent_pid);
54 __bionic_atfork_run_parent();
55 }
56 return result;
57 }
58