sysdeps/posix/sigset.c

   1 /* Copyright (C) 1998 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Library General Public License as
   6    published by the Free Software Foundation; either version 2 of the
   7    License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Library General Public License for more details.
  13
  14    You should have received a copy of the GNU Library General Public
  15    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  16    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17    Boston, MA 02111-1307, USA.  */
  18
  19 #include <errno.h>
  20 #define __need_NULL
  21 #include <stddef.h>
  22 #include <signal.h>
  23
  24
  25 /* Set the disposition for SIG.  */
  26 __sighandler_t
  27 sigset (sig, disp)
  28      int sig;
  29      __sighandler_t disp;
  30 {
  31   struct sigaction act, oact;
  32
  33 #ifdef SIG_HOLD
  34   /* Handle SIG_HOLD first.  */
  35   if (disp == SIG_HOLD)
  36     {
  37       sigset_t set;
  38
  39       /* Retrieve current signal set.  */
  40       if (__sigprocmask (SIG_SETMASK, NULL, &set) < 0)
  41         return SIG_ERR;
  42
  43       /* Add the specified signal.  */
  44       if (sigaddset (&set, sig) < 0)
  45         return SIG_ERR;
  46
  47       /* Set the new mask.  */
  48       if (__sigprocmask (SIG_SETMASK, &set, NULL) < 0)
  49         return SIG_ERR;
  50
  51       return SIG_HOLD;
  52     }
  53 #endif  /* SIG_HOLD */
  54
  55   /* Check signal extents to protect __sigismember.  */
  56   if (disp == SIG_ERR || sig < 1 || sig >= NSIG)
  57     {
  58       __set_errno (EINVAL);
  59       return SIG_ERR;
  60     }
  61
  62   act.sa_handler = disp;
  63   if (__sigemptyset (&act.sa_mask) < 0)
  64     return SIG_ERR;
  65   act.sa_flags = 0;
  66   if (__sigaction (sig, &act, &oact) < 0)
  67     return SIG_ERR;
  68
  69   return oact.sa_handler;
  70 }