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/* Copyright (C) 1996 Free Software Foundation, Inc.
Contributed by Richard Henderson (rth@tamu.edu)
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
Cambridge, MA 02139, USA. */
/* clone() is even more special than fork() as it mucks with stacks
and invokes a function in the right context after its all over. */
#include <sysdep.h>
#define _ERRNO_H 1
#include <errnos.h>
/* int clone(int (*fn)(), void *child_stack, int flags, int nargs, ...) */
.text
ENTRY(__clone)
/* Sanity check arguments. */
movl $-EINVAL,%eax
movl 4(%esp),%ecx /* no NULL function pointers */
testl %ecx,%ecx
jz syscall_error
movl 8(%esp),%ecx /* no NULL stack pointers */
testl %ecx,%ecx
jz syscall_error
movl 16(%esp),%edx /* no negative argument counts */
testl %edx,%edx
js syscall_error
/* Allocate space on the new stack and copy args over */
movl %edx,%eax
negl %eax
lea -4(%ecx,%eax,4),%ecx
jz 2f
1: movl 16(%esp,%edx,4),%eax
movl %eax,0(%ecx,%edx,4)
dec %edx
jnz 1b
2:
/* Save the function pointer as the zeroth argument.
It will be popped off in the child in the ebx frobbing below. */
movl 4(%esp),%eax
movl %eax,0(%ecx)
/* Do the system call */
pushl %ebx
movl 16(%esp),%ebx
movl $SYS_ify(clone),%eax
int $0x80
popl %ebx
test %eax,%eax
jl syscall_error
jz thread_start
ret
.size __clone,.-__clone
SYSCALL_ERROR_HANDLER
thread_start:
subl %ebp,%ebp /* terminate the stack frame */
call *%ebx
pushl %eax
#ifdef PIC
call _exit@PLT
#else
call _exit
#endif
weak_alias(__clone, clone)
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