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glibc  2.9
sysv_signal.c
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00001 /* Copyright (C) 1991, 1992, 1996, 1997, 2005 Free Software Foundation, Inc.
00002    This file is part of the GNU C Library.
00003 
00004    The GNU C Library is free software; you can redistribute it and/or
00005    modify it under the terms of the GNU Lesser General Public
00006    License as published by the Free Software Foundation; either
00007    version 2.1 of the License, or (at your option) any later version.
00008 
00009    The GNU C Library is distributed in the hope that it will be useful,
00010    but WITHOUT ANY WARRANTY; without even the implied warranty of
00011    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00012    Lesser General Public License for more details.
00013 
00014    You should have received a copy of the GNU Lesser General Public
00015    License along with the GNU C Library; if not, write to the Free
00016    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
00017    02111-1307 USA.  */
00018 
00019 #include <errno.h>
00020 #include <signal.h>
00021 #include <string.h>  /* For the real memset prototype.  */
00022 
00023 
00024 /* Tolerate non-threads versions of Posix */
00025 #ifndef SA_ONESHOT
00026 #define SA_ONESHOT 0
00027 #endif
00028 #ifndef SA_NOMASK
00029 #define SA_NOMASK 0
00030 #endif
00031 #ifndef SA_INTERRUPT
00032 #define SA_INTERRUPT 0
00033 #endif
00034 
00035 /* Set the handler for the signal SIG to HANDLER,
00036    returning the old handler, or SIG_ERR on error.  */
00037 __sighandler_t
00038 __sysv_signal (sig, handler)
00039      int sig;
00040      __sighandler_t handler;
00041 {
00042   struct sigaction act, oact;
00043 
00044   /* Check signal extents to protect __sigismember.  */
00045   if (handler == SIG_ERR || sig < 1 || sig >= NSIG)
00046     {
00047       __set_errno (EINVAL);
00048       return SIG_ERR;
00049     }
00050 
00051   act.sa_handler = handler;
00052   if (__sigemptyset (&act.sa_mask) < 0)
00053     return SIG_ERR;
00054   act.sa_flags = SA_ONESHOT | SA_NOMASK | SA_INTERRUPT;
00055   act.sa_flags &= ~SA_RESTART;
00056   if (__sigaction (sig, &act, &oact) < 0)
00057     return SIG_ERR;
00058 
00059   return oact.sa_handler;
00060 }
00061 
00062 weak_alias (__sysv_signal, sysv_signal)