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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
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Mar 9, 2004
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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. */ | ||
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#include <sysdep.h> | ||
#define _ERRNO_H 1 | ||
#include <bits/errno.h> | ||
#include <kernel-features.h> | ||
#include <tcb-offsets.h> | ||
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/* 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. */ | ||
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ENTRY (__vfork) | ||
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#ifdef __NR_vfork | ||
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/* Pop the return PC value into ECX. */ | ||
popl %ecx | ||
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/* Save the PID value. */ | ||
movl %gs:PID, %edx | ||
movl $-1, %gs:PID | ||
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/* Stuff the syscall number in EAX and enter into the kernel. */ | ||
movl $SYS_ify (vfork), %eax | ||
int $0x80 | ||
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/* 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 | ||
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/* Restore the old PID value in the parent. In the child store 0. */ | ||
testl %eax, %eax | ||
je 1f | ||
movl %edx, %gs:PID | ||
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1: cmpl $-4095, %eax | ||
/* Branch forward if it failed. */ | ||
# ifdef __ASSUME_VFORK_SYSCALL | ||
jae SYSCALL_ERROR_LABEL | ||
.Lpseudo_end: | ||
# else | ||
jae .Lerror | ||
# endif | ||
ret | ||
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# ifndef __ASSUME_VFORK_SYSCALL | ||
.Lerror: | ||
/* Check if vfork syscall is known at all. */ | ||
cmpl $-ENOSYS, %eax | ||
jne SYSCALL_ERROR_LABEL | ||
# endif | ||
#endif | ||
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#ifndef __ASSUME_VFORK_SYSCALL | ||
/* If we don't have vfork, fork is close enough. */ | ||
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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) | ||
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weak_alias (__vfork, vfork) |