usr/src/lib/libc/port/gen/ssignal.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21
  22 /*
  23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26
  27 /*      Copyright (c) 1988 AT&T */
  28 /*        All Rights Reserved   */
  29
  30 #pragma ident   "%Z%%M% %I%     %E% SMI"
  31
  32 /*
  33  *      ssignal, gsignal: software signals
  34  */
  35
  36 #include "lint.h"
  37 #include <sys/types.h>
  38 #include <signal.h>
  39
  40 /* Highest allowable user signal number */
  41 #define MAXSIGNUM       17
  42
  43 /* Lowest allowable signal number (lowest user number is always 1) */
  44 #define MINSIG  (-4)
  45
  46 /* Table of signal values */
  47 static int (*sigs[MAXSIGNUM-MINSIG+1])(int);
  48
  49 int (*
  50 ssignal(int sig, int (*action)(int)))(int)
  51 {
  52         int (*savefn)(int);
  53
  54         if (sig >= MINSIG && sig <= MAXSIGNUM) {
  55                 savefn = sigs[sig-MINSIG];
  56                 sigs[sig-MINSIG] = action;
  57         } else
  58                 savefn = (int(*)(int))SIG_DFL;
  59
  60         return (savefn);
  61 }
  62
  63 int
  64 gsignal(int sig)
  65 {
  66         int (*sigfn)(int);
  67
  68         if (sig < MINSIG || sig > MAXSIGNUM ||
  69             (sigfn = sigs[sig-MINSIG]) == (int(*)(int))SIG_DFL)
  70                 return (0);
  71         else if (sigfn == (int(*)(int))SIG_IGN)
  72                 return (1);
  73         else {
  74                 sigs[sig-MINSIG] = (int(*)(int))SIG_DFL;
  75                 return ((*sigfn)(sig));
  76         }
  77 }