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	* sysdeps/i386/tcb-offsets.sym: Add PID.
	* sysdeps/unix/sysv/linux/i386/vfork.S: New file.
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Ulrich Drepper committed Mar 9, 2004
1 parent 02287d0 commit c072ef6
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3 changes: 2 additions & 1 deletion nptl/ChangeLog
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2004-03-08 Ulrich Drepper <drepper@redhat.com>

* nptl/sysdeps/i386/tcb-offsets.sym: Add PID.
* sysdeps/i386/tcb-offsets.sym: Add PID.
* sysdeps/unix/sysv/linux/i386/vfork.S: New file.

2004-03-08 Steven Munroe <sjmunroe@us.ibm.com>

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87 changes: 87 additions & 0 deletions nptl/sysdeps/unix/sysv/linux/i386/vfork.S
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/* Copyright (C) 1999, 2002, 2004 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Andreas Schwab <schwab@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>
#include <tcb-offsets.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

/* Pop the return PC value into ECX. */
popl %ecx

/* Save the PID value. */
movl %gs:PID, %edx
movl $-1, %gs:PID

/* Stuff the syscall number in EAX and enter into the kernel. */
movl $SYS_ify (vfork), %eax
int $0x80

/* Jump to the return PC. Don't jump directly since this
disturbs the branch target cache. Instead push the return
address back on the stack. */
pushl %ecx

/* Restore the old PID value in the parent. In the child store 0. */
testl %eax, %eax
je 1f
movl %edx, %gs:PID

1: cmpl $-4095, %eax
/* Branch forward if it failed. */
# ifdef __ASSUME_VFORK_SYSCALL
jae SYSCALL_ERROR_LABEL
.Lpseudo_end:
# else
jae .Lerror
# endif
ret

# ifndef __ASSUME_VFORK_SYSCALL
.Lerror:
/* Check if vfork syscall is known at all. */
cmpl $-ENOSYS, %eax
jne SYSCALL_ERROR_LABEL
# endif
#endif

#ifndef __ASSUME_VFORK_SYSCALL
/* If we don't have vfork, fork is close enough. */

movl $SYS_ify (fork), %eax
int $0x80
cmpl $-4095, %eax
jae SYSCALL_ERROR_LABEL
.Lpseudo_end:
ret
#endif
PSEUDO_END (__vfork)
libc_hidden_def (__vfork)

weak_alias (__vfork, vfork)

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