/* Copyright (C) 1991-2018 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

   <http://www.gnu.org/licenses/>.  */

#include <errno.h>

#include <signal.h>

#include <string.h>	/* For the real memset prototype.  */

#include <sigsetops.h>

/* Tolerate non-threads versions of Posix */

#ifndef SA_ONESHOT

#define SA_ONESHOT 0

#endif

#ifndef SA_NOMASK

#define SA_NOMASK 0

#endif

#ifndef SA_INTERRUPT

#define SA_INTERRUPT 0

#endif

/* Set the handler for the signal SIG to HANDLER,

   returning the old handler, or SIG_ERR on error.  */

__sighandler_t

__sysv_signal (int sig, __sighandler_t handler)

{

  struct sigaction act, oact;

  /* Check signal extents to protect __sigismember.  */

  if (handler == SIG_ERR || sig < 1 || sig >= NSIG)

    {

      __set_errno (EINVAL);

      return SIG_ERR;

    }

  act.sa_handler = handler;

  __sigemptyset (&act.sa_mask);

  act.sa_flags = SA_ONESHOT | SA_NOMASK | SA_INTERRUPT;

  act.sa_flags &= ~SA_RESTART;

  if (__sigaction (sig, &act, &oact) < 0)

    return SIG_ERR;

  return oact.sa_handler;

}

weak_alias (__sysv_signal, sysv_signal)