sysdeps/posix/sysv_signal.c

   1 /* Copyright (C) 1991, 1992, 1996, 1997, 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 #include <signal.h>
  21 #include <string.h>     /* For the real memset prototype.  */
  22
  23
  24 /* Tolerate non-threads versions of Posix */
  25 #ifndef SA_ONESHOT
  26 #define SA_ONESHOT 0
  27 #endif
  28 #ifndef SA_NOMASK
  29 #define SA_NOMASK 0
  30 #endif
  31 #ifndef SA_INTERRUPT
  32 #define SA_INTERRUPT 0
  33 #endif
  34
  35 /* Set the handler for the signal SIG to HANDLER,
  36    returning the old handler, or SIG_ERR on error.  */
  37 __sighandler_t
  38 __sysv_signal (sig, handler)
  39      int sig;
  40      __sighandler_t handler;
  41 {
  42   struct sigaction act, oact;
  43
  44   /* Check signal extents to protect __sigismember.  */
  45   if (handler == SIG_ERR || sig < 1 || sig >= NSIG)
  46     {
  47       __set_errno (EINVAL);
  48       return SIG_ERR;
  49     }
  50
  51   act.sa_handler = handler;
  52   if (__sigemptyset (&act.sa_mask) < 0)
  53     return SIG_ERR;
  54   act.sa_flags = SA_ONESHOT | SA_NOMASK | SA_INTERRUPT;
  55   act.sa_flags &= ~SA_RESTART;
  56   if (__sigaction (sig, &act, &oact) < 0)
  57     return SIG_ERR;
  58
  59   return oact.sa_handler;
  60 }
  61
  62 weak_alias (__sysv_signal, sysv_signal)