sysdeps/posix/signal.c

   1 /* BSD-like signal function.
   2    Copyright (C) 1991-2014 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 Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the 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    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <errno.h>
  20 #include <signal.h>
  21 #include <string.h>     /* For the real memset prototype.  */
  22
  23
  24 sigset_t _sigintr attribute_hidden;             /* 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       || __sigaddset (&act.sa_mask, sig) < 0)
  45     return SIG_ERR;
  46   act.sa_flags = __sigismember (&_sigintr, sig) ? 0 : SA_RESTART;
  47   if (__sigaction (sig, &act, &oact) < 0)
  48     return SIG_ERR;
  49
  50   return oact.sa_handler;
  51 }
  52 weak_alias (__bsd_signal, bsd_signal)
  53 weak_alias (__bsd_signal, signal)
  54 weak_alias (__bsd_signal, ssignal)