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glibc/sysdeps/unix/sysv/linux/i386/vfork.S
Siddhesh Poyarekar 30891f35fa Remove "Contributed by" lines
We stopped adding "Contributed by" or similar lines in sources in 2012
in favour of git logs and keeping the Contributors section of the
glibc manual up to date.  Removing these lines makes the license
header a bit more consistent across files and also removes the
possibility of error in attribution when license blocks or files are
copied across since the contributed-by lines don't actually reflect
reality in those cases.

Move all "Contributed by" and similar lines (Written by, Test by,
etc.) into a new file CONTRIBUTED-BY to retain record of these
contributions.  These contributors are also mentioned in
manual/contrib.texi, so we just maintain this additional record as a
courtesy to the earlier developers.

The following scripts were used to filter a list of files to edit in
place and to clean up the CONTRIBUTED-BY file respectively.  These
were not added to the glibc sources because they're not expected to be
of any use in future given that this is a one time task:

https://gist.github.com/siddhesh/b5ecac94eabfd72ed2916d6d8157e7dc
https://gist.github.com/siddhesh/15ea1f5e435ace9774f485030695ee02

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2021-09-03 22:06:44 +05:30

79 lines
2.3 KiB
ArmAsm

/* Copyright (C) 1999-2021 Free Software Foundation, Inc.
This file is part of the GNU C Library.
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
<https://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)
/* Pop the return PC value into ECX. */
popl %ecx
cfi_adjust_cfa_offset (-4)
cfi_register (%eip, %ecx)
/* 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
cfi_adjust_cfa_offset (4)
cmpl $-4095, %eax
/* Branch forward if it failed. */
jae SYSCALL_ERROR_LABEL
#if SHSTK_ENABLED
/* Check if shadow stack is in use. */
xorl %edx, %edx
rdsspd %edx
testl %edx, %edx
/* Normal return if shadow stack isn't in use. */
je L(no_shstk)
testl %eax, %eax
/* In parent, normal return. */
jnz L(no_shstk)
/* NB: In child, jump back to caller via indirect branch without
popping shadow stack which is shared with parent. Keep shadow
stack mismatched so that child returns in the vfork-calling
function will trigger SIGSEGV. */
popl %ecx
cfi_adjust_cfa_offset (-4)
jmp *%ecx
L(no_shstk):
#endif
ret
PSEUDO_END (__vfork)
libc_hidden_def (__vfork)
weak_alias (__vfork, vfork)
strong_alias (__vfork, __libc_vfork)