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* sysdeps/unix/sysv/linux/i386/vfork.S: If SAVE_PID and
	RESTORE_PID are defined, use it.
	* sysdeps/unix/sysv/linux/x86_64/vfork.S: Likewise.
This commit is contained in:
Ulrich Drepper
2004-03-09 06:32:58 +00:00
parent c072ef6d22
commit 6fadea9f1d
8 changed files with 67 additions and 64 deletions
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73
nptl/sysdeps/unix/sysv/linux/i386/vfork.S
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@ -1,6 +1,5 @@
/* 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
@ -17,71 +16,19 @@
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
/* Save the PID value. */
#define SAVE_PID \
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
/* Restore the old PID value in the parent. In the child store 0. */
#define RESTORE_PID \
testl %eax, %eax; \
je 1f; \
movl %edx, %gs:PID; \
1:
/* 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)
#include <sysdeps/unix/sysv/linux/i386/vfork.S>