text: /* Copyright (C) 1998-2015 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>
  #define __need_NULL
  #include <stddef.h>
  #include <signal.h>
  #include <string.h>	/* For the real memset prototype.  */
  
  
  /* Set the disposition for SIG.  */
  __sighandler_t
  sigset (sig, disp)
       int sig;
       __sighandler_t disp;
  {
    struct sigaction act;
    struct sigaction oact;
    sigset_t set;
    sigset_t oset;
  
  #ifdef SIG_HOLD
    /* Handle SIG_HOLD first.  */
    if (disp == SIG_HOLD)
      {
        /* Create an empty signal set.  */
        if (__sigemptyset (&set) < 0)
  	return SIG_ERR;
  
        /* Add the specified signal.  */
        if (__sigaddset (&set, sig) < 0)
  	return SIG_ERR;
  
        /* Add the signal set to the current signal mask.  */
        if (__sigprocmask (SIG_BLOCK, &set, &oset) < 0)
  	return SIG_ERR;
  
        /* If the signal was already blocked signal this to the caller.  */
        if (__sigismember (&oset, sig))
  	return SIG_HOLD;
  
        /* We need to determine whether a specific handler is installed.  */
        if (__sigaction (sig, NULL, &oact) < 0)
  	return SIG_ERR;
  
        return oact.sa_handler;
      }
  #endif	/* SIG_HOLD */
  
    /* Check signal extents to protect __sigismember.  */
    if (disp == SIG_ERR || sig < 1 || sig >= NSIG)
      {
        __set_errno (EINVAL);
        return SIG_ERR;
      }
  
    act.sa_handler = disp;
    if (__sigemptyset (&act.sa_mask) < 0)
      return SIG_ERR;
    act.sa_flags = 0;
    if (__sigaction (sig, &act, &oact) < 0)
      return SIG_ERR;
  
    /* Create an empty signal set.  */
    if (__sigemptyset (&set) < 0)
      return SIG_ERR;
  
    /* Add the specified signal.  */
    if (__sigaddset (&set, sig) < 0)
      return SIG_ERR;
  
    /* Remove the signal set from the current signal mask.  */
    if (__sigprocmask (SIG_UNBLOCK, &set, &oset) < 0)
      return SIG_ERR;
  
    /* If the signal was already blocked return SIG_HOLD.  */
    return __sigismember (&oset, sig) ? SIG_HOLD : oact.sa_handler;
  }
  