clone.cpp revision 954cf0d4e2669f91194b45f484152e47efa4f6c7 
1/*
2 * Copyright (C) 2010 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#define __GNU_SOURCE 1
30#include <sched.h>
31#include <stdlib.h>
32#include <stdarg.h>
33
34extern "C" pid_t __bionic_clone(uint32_t flags, void* child_stack, int* parent_tid, void* tls, int* child_tid, int (*fn)(void*), void* arg);
35extern "C" void __exit(int status);
36
37// Called from the __bionic_clone assembler to call the thread function then exit.
38extern "C" __LIBC_HIDDEN__ void __bionic_clone_entry(int (*fn)(void*), void* arg) {
39  int status = (*fn)(arg);
40  __exit(status);
41}
42
43int clone(int (*fn)(void*), void* child_stack, int flags, void* arg, ...) {
44  int* parent_tid = NULL;
45  void* new_tls = NULL;
46  int* child_tid = NULL;
47
48  // Extract any optional parameters required by the flags.
49  va_list args;
50  va_start(args, arg);
51  if ((flags & (CLONE_PARENT_SETTID|CLONE_SETTLS|CLONE_CHILD_SETTID|CLONE_CHILD_CLEARTID)) != 0) {
52    parent_tid = va_arg(args, int*);
53  }
54  if ((flags & (CLONE_SETTLS|CLONE_CHILD_SETTID|CLONE_CHILD_CLEARTID)) != 0) {
55    new_tls = va_arg(args, void*);
56  }
57  if ((flags & (CLONE_CHILD_SETTID|CLONE_CHILD_CLEARTID)) != 0) {
58    child_tid = va_arg(args, int*);
59  }
60  va_end(args);
61
62  return __bionic_clone(flags, child_stack, parent_tid, new_tls, child_tid, fn, arg);
63}
64