clone.cpp revision 0d236aa3f1e6d31b0c729448ae9d3ed1cad23fb4
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 // Align 'child_stack' to 16 bytes. 63 uintptr_t child_stack_addr = reinterpret_cast<uintptr_t>(child_stack); 64 child_stack_addr &= ~0xf; 65 child_stack = reinterpret_cast<void*>(child_stack_addr); 66 67 return __bionic_clone(flags, child_stack, parent_tid, new_tls, child_tid, fn, arg); 68} 69