sysdeps/posix/signal.c

   1 /* Copyright (C) 1991, 1992, 1996 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 #include <signal.h>
  21
  22
  23 sigset_t _sigintr;              /* Set by siginterrupt.  */
  24
  25 /* Set the handler for the signal SIG to HANDLER,
  26    returning the old handler, or SIG_ERR on error.  */
  27 __sighandler_t
  28 signal (sig, handler)
  29      int sig;
  30      __sighandler_t handler;
  31 {
  32   struct sigaction act, oact;
  33
  34   /* Check signal extents to protect __sigismember.  */
  35   if (handler == SIG_ERR || sig < 1 || sig >= NSIG)
  36     {
  37       __set_errno (EINVAL);
  38       return SIG_ERR;
  39     }
  40
  41   act.sa_handler = handler;
  42   if (__sigemptyset (&act.sa_mask) < 0)
  43     return SIG_ERR;
  44   act.sa_flags = __sigismember (&_sigintr, sig) ? 0 : SA_RESTART;
  45   if (__sigaction (sig, &act, &oact) < 0)
  46     return SIG_ERR;
  47
  48   return oact.sa_handler;
  49 }