signal.c

用于嵌入式Linux系统的标准C的库函数

/* BSD-like signal function.
   Copyright (C) 1991, 1992, 1996, 1997, 2000 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, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

#include <errno.h>
#include <signal.h>
#include <machine/weakalias.h>

sigset_t _sigintr;		/* Set by siginterrupt.  */

/* Set the handler for the signal SIG to HANDLER,
   returning the old handler, or SIG_ERR on error.  */
__sighandler_t
__bsd_signal (sig, handler)
     int sig;
     __sighandler_t handler;
{
  struct sigaction act, oact;

  /* Check signal extents to protect __sigismember.  */
  if (handler == SIG_ERR || sig < 1 || sig >= NSIG)
    {
      errno = (EINVAL);
      return SIG_ERR;
    }

  act.sa_handler = handler;
  if (sigemptyset (&act.sa_mask) < 0
      || sigaddset (&act.sa_mask, sig) < 0)
    return SIG_ERR;
  act.sa_flags = sigismember (&_sigintr, sig) ? 0 : SA_RESTART;
  if (sigaction (sig, &act, &oact) < 0)
    return SIG_ERR;

  return oact.sa_handler;
}
weak_alias (__bsd_signal, bsd_signal)
weak_alias (__bsd_signal, signal)
weak_alias (__bsd_signal, ssignal)