/* * Copyright (c) 1999-2003 Apple Computer, Inc. All rights reserved. * * @APPLE_LICENSE_HEADER_START@ * * This file contains Original Code and/or Modifications of Original Code * as defined in and that are subject to the Apple Public Source License * Version 2.0 (the 'License'). You may not use this file except in * compliance with the License. Please obtain a copy of the License at * http://www.opensource.apple.com/apsl/ and read it before using this * file. * * The Original Code and all software distributed under the License are * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. * Please see the License for the specific language governing rights and * limitations under the License. * * @APPLE_LICENSE_HEADER_END@ */ /* * Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */ #include <SYS.h> /* * If __current_pid >= 0, we want to put a -1 in there * otherwise we just decrement it */ LEAF(_vfork, 0) movq __current_pid@GOTPCREL(%rip), %rax movl (%rax), %eax 0: xorl %ecx, %ecx testl %eax, %eax cmovs %eax, %ecx subl $1, %ecx movq __current_pid@GOTPCREL(%rip), %rdx lock cmpxchgl %ecx, (%rdx) jne 0b popq %rdi // return address in %rdi movq $ SYSCALL_CONSTRUCT_UNIX(SYS_vfork), %rax // code for vfork -> rax UNIX_SYSCALL_TRAP // do the system call jnb L1 // jump if CF==0 movq __current_pid@GOTPCREL(%rip), %rcx lock addq $1, (%rcx) movq (%rcx), %rdi BRANCH_EXTERN(cerror) L1: testl %edx, %edx // CF=OF=0, ZF set if zero result jz L2 // parent, since r1 == 0 in parent, 1 in child xorq %rax, %rax // zero rax jmp *%rdi L2: movq __current_pid@GOTPCREL(%rip), %rdx lock addq $1, (%rdx) jmp *%rdi