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/* Copyright (C) 1992, 1993, 1994, 1995 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 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. */
#include <ansidecl.h>
#include <errno.h>
#include <hurd.h>
#include <hurd/signal.h>
/* Run signals handlers on the stack specified by SS (if not NULL).
If OSS is not NULL, it is filled in with the old signal stack status. */
int
DEFUN(sigaltstack, (ss, oss),
CONST struct sigaltstack *argss AND struct sigaltstack *oss)
{
struct hurd_sigstate *s;
struct sigaltstack ss, old;
/* Fault before taking any locks. */
if (argss != NULL)
ss = *argss;
if (oss != NULL)
*(volatile struct sigaltstack *) oss = *oss;
s = _hurd_self_sigstate ();
__spin_lock (&s->lock);
if (argss != NULL &&
(ss.ss_flags & SA_DISABLE) && (s->sigaltstack.ss_flags & SA_ONSTACK))
{
/* Can't disable a stack that is in use. */
__spin_unlock (&s->lock);
errno = EINVAL;
return -1;
}
old = s->sigaltstack;
if (argss != NULL)
s->sigaltstack = ss;
__spin_unlock (&s->lock);
if (oss != NULL)
*oss = old;
return 0;
}
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