sysdeps/posix/sysv_signal.c

   1 /* Copyright (C) 1991, 1992, 1996, 1997 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 /* Tolerate non-threads versions of Posix */
  23 #ifndef SA_ONESHOT
  24 #define SA_ONESHOT 0
  25 #endif
  26 #ifndef SA_NOMASK
  27 #define SA_NOMASK 0
  28 #endif
  29 #ifndef SA_INTERRUPT
  30 #define SA_INTERRUPT 0
  31 #endif
  32
  33 /* Set the handler for the signal SIG to HANDLER,
  34    returning the old handler, or SIG_ERR on error.  */
  35 __sighandler_t
  36 __sysv_signal (sig, handler)
  37      int sig;
  38      __sighandler_t handler;
  39 {
  40   struct sigaction act, oact;
  41
  42   /* Check signal extents to protect __sigismember.  */
  43   if (handler == SIG_ERR || sig < 1 || sig >= NSIG)
  44     {
  45       __set_errno (EINVAL);
  46       return SIG_ERR;
  47     }
  48
  49   act.sa_handler = handler;
  50   if (__sigemptyset (&act.sa_mask) < 0)
  51     return SIG_ERR;
  52   act.sa_flags = SA_ONESHOT | SA_NOMASK | SA_INTERRUPT;
  53   act.sa_flags &= ~SA_RESTART;
  54   if (__sigaction (sig, &act, &oact) < 0)
  55     return SIG_ERR;
  56
  57   return oact.sa_handler;
  58 }
  59
  60 weak_alias (__sysv_signal, sysv_signal)