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/* Copyright (C) 1999, 2002 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include <sysdep.h>
/* Clone the calling process, but without copying the whole address space.
The calling process is suspended until the new process exits or is
replaced by a call to `execve'. Return -1 for errors, 0 to the new process,
and the process ID of the new process to the old process. */
ENTRY (__vfork)
/* Pop the return PC value into RDI. */
popq %rdi
cfi_adjust_cfa_offset(-8)
cfi_register(%rip, %rdi)
/* Perform the system call. */
DO_CALL (vfork, 0)
jb L(error) /* Branch forward if it failed. */
/* In the parent process, %rdx == 0, %rax == child pid. */
/* In the child process, %rdx == 1, %rax == parent pid. */
/* Change %rax to be 0 in the child process. */
decq %rdx
andq %rdx, %rax
/* Jump to the return PC. */
jmp *%rdi
L(error):
/* Push back the return PC. */
pushq %rdi
cfi_adjust_cfa_offset(8)
/* Branch to the error handler, hidden in PSEUDO_END. */
jmp SYSCALL_ERROR_LABEL
L(pseudo_end):
ret
PSEUDO_END (__vfork)
libc_hidden_def (__vfork)
weak_alias (__vfork, vfork)
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