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/* Copyright (C) 1999-2016 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, see
<http://www.gnu.org/licenses/>. */
#include <sysdep.h>
#define _ERRNO_H 1
#include <bits/errno.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)
/* Save the PID value. */
GET_TLS (r2)
NEGOFF_ADJ_BASE2 (r2, r0, PID_OFFSET) /* Save the TLS addr in r2. */
ldr r3, NEGOFF_OFF1 (r2, PID_OFFSET) /* Load the saved PID. */
rsbs r0, r3, #0 /* Negate it, and test for zero. */
/* Use 0x80000000 if it was 0. See raise.c for how this is used. */
it eq
moveq r0, #0x80000000
str r0, NEGOFF_OFF1 (r2, PID_OFFSET) /* Store the temp PID. */
/* The DO_CALL macro saves r7 on the stack, to enable generation
of ARM unwind info. Since the stack is initially shared between
parent and child of vfork, that saved value could be corrupted.
To avoid this problem, we save r7 into ip as well, and restore
from there. */
mov ip, r7
cfi_register (r7, ip)
.fnstart
push { r7 }
cfi_adjust_cfa_offset (4)
.save { r7 }
ldr r7, =SYS_ify (vfork)
swi 0x0
.fnend
add sp, sp, #4
cfi_adjust_cfa_offset (-4)
mov r7, ip
cfi_restore (r7)
/* Restore the old PID value in the parent. */
cmp r0, #0 /* If we are the parent... */
it ne
strne r3, NEGOFF_OFF1 (r2, PID_OFFSET) /* restore the saved PID. */
cmn a1, #4096
it cc
RETINSTR(cc, lr)
b PLTJMP(SYSCALL_ERROR)
PSEUDO_END (__vfork)
libc_hidden_def (__vfork)
weak_alias (__vfork, vfork)
strong_alias (__vfork, __libc_vfork)
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