sysdeps/posix/bsd_signal.c

   1 /* X/Open compatibility function.
   2    Copyright (C) 1991, 1992, 1996 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Library General Public License as
   7    published by the Free Software Foundation; either version 2 of the
   8    License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Library General Public License for more details.
  14
  15    You should have received a copy of the GNU Library General Public
  16    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  17    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18    Boston, MA 02111-1307, USA.  */
  19
  20 #include <errno.h>
  21 #include <signal.h>
  22
  23
  24 sigset_t _sigintr;              /* Set by siginterrupt.  */
  25
  26 /* Set the handler for the signal SIG to HANDLER,
  27    returning the old handler, or SIG_ERR on error.  */
  28 __sighandler_t
  29 bsd_signal (sig, handler)
  30      int sig;
  31      __sighandler_t handler;
  32 {
  33   struct sigaction act, oact;
  34
  35   /* Check signal extents to protect __sigismember.  */
  36   if (handler == SIG_ERR || sig < 1 || sig >= NSIG)
  37     {
  38       __set_errno (EINVAL);
  39       return SIG_ERR;
  40     }
  41
  42   act.sa_handler = handler;
  43   if (__sigemptyset (&act.sa_mask) < 0)
  44     return SIG_ERR;
  45   act.sa_flags = __sigismember (&_sigintr, sig) ? 0 : SA_RESTART;
  46   if (__sigaction (sig, &act, &oact) < 0)
  47     return SIG_ERR;
  48
  49   return oact.sa_handler;
  50 }