glibc/sysdeps/unix/sysv/linux/arm/vfork.S

/* Copyright (C) 1999, 2002, 2003 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Philip Blundell <philb@gnu.org>.

   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>
#define _ERRNO_H	1
#include <bits/errno.h>
#include <kernel-features.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)

#ifdef __NR_vfork
	swi	__NR_vfork
	cmn	a1, #4096
	RETINSTR(cc, lr)

# ifdef __ASSUME_VFORK_SYSCALL
	b	PLTJMP(C_SYMBOL_NAME(__syscall_error))
# else
	/* Check if vfork syscall is known at all.  */
	cmn	a2, #ENOSYS
	bne	PLTJMP(C_SYMBOL_NAME(__syscall_error))
# endif
#endif

#ifndef __ASSUME_VFORK_SYSCALL
	/* If we don't have vfork, fork is close enough.  */
	swi	__NR_fork
	cmn	a1, #4096
	RETINSTR(cc, lr)
    	b	PLTJMP(C_SYMBOL_NAME(__syscall_error))
#elif !defined __NR_vfork
# error "__NR_vfork not available and __ASSUME_VFORK_SYSCALL defined"
#endif

PSEUDO_END (__vfork)
libc_hidden_def (__vfork)

weak_alias (__vfork, vfork)