sysdeps/posix/sigset.c

   1 /* Copyright (C) 1998, 2000, 2005 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 Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the 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    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    02111-1307 USA.  */
  18
  19 #include <errno.h>
  20 #define __need_NULL
  21 #include <stddef.h>
  22 #include <signal.h>
  23 #include <string.h>     /* For the real memset prototype.  */
  24
  25
  26 /* Set the disposition for SIG.  */
  27 __sighandler_t
  28 sigset (sig, disp)
  29      int sig;
  30      __sighandler_t disp;
  31 {
  32   struct sigaction act, oact;
  33   sigset_t set;
  34
  35 #ifdef SIG_HOLD
  36   /* Handle SIG_HOLD first.  */
  37   if (disp == SIG_HOLD)
  38     {
  39       /* Create an empty signal set.  */
  40       if (__sigemptyset (&set) < 0)
  41         return SIG_ERR;
  42
  43       /* Add the specified signal.  */
  44       if (__sigaddset (&set, sig) < 0)
  45         return SIG_ERR;
  46
  47       /* Add the signal set to the current signal mask.  */
  48       if (__sigprocmask (SIG_BLOCK, &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   /* Create an empty signal set.  */
  70   if (__sigemptyset (&set) < 0)
  71     return SIG_ERR;
  72
  73   /* Add the specified signal.  */
  74   if (__sigaddset (&set, sig) < 0)
  75     return SIG_ERR;
  76
  77   /* Remove the signal set from the current signal mask.  */
  78   if (__sigprocmask (SIG_UNBLOCK, &set, NULL) < 0)
  79     return SIG_ERR;
  80
  81   return oact.sa_handler;
  82 }