sig.c revision 45126 
1/*-
2 * Copyright (c) 1997 Brian Somers <brian@Awfulhak.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 *	$Id: sig.c,v 1.13 1998/05/21 21:48:20 brian Exp $
27 */
28
29#include <sys/types.h>
30
31#include <signal.h>
32
33#include "log.h"
34#include "sig.h"
35
36static int caused[NSIG];	/* An array of pending signals */
37static int necessary;		/* Anything set ? */
38static sig_type handler[NSIG];	/* all start at SIG_DFL */
39
40
41/* Record a signal in the "caused" array */
42
43static void
44signal_recorder(int sig)
45{
46  caused[sig - 1]++;
47  necessary = 1;
48}
49
50
51/*
52 * Set up signal_recorder, and record handler as the function to ultimately
53 * call in handle_signal()
54*/
55
56sig_type
57sig_signal(int sig, sig_type fn)
58{
59  sig_type Result;
60
61  if (sig <= 0 || sig > NSIG) {
62    /* Oops - we must be a bit out of date (too many sigs ?) */
63    log_Printf(LogALERT, "Eeek! %s:%d: I must be out of date!\n",
64	      __FILE__, __LINE__);
65    return signal(sig, fn);
66  }
67  Result = handler[sig - 1];
68  if (fn == SIG_DFL || fn == SIG_IGN) {
69    signal(sig, fn);
70    handler[sig - 1] = (sig_type) 0;
71  } else {
72    handler[sig - 1] = fn;
73    signal(sig, signal_recorder);
74  }
75  caused[sig - 1] = 0;
76  return Result;
77}
78
79
80/* Call the handlers for any pending signals */
81
82int
83sig_Handle()
84{
85  int sig;
86  int got;
87  int result;
88
89  result = 0;
90  if (necessary) {
91    /* We've *probably* got something in `caused' set */
92    necessary = 0;
93    /* `necessary' might go back to 1 while we're in here.... */
94    do {
95      got = 0;
96      for (sig = 0; sig < NSIG; sig++)
97        if (caused[sig]) {
98	  caused[sig]--;
99	  got++;
100	  result++;
101	  (*handler[sig])(sig + 1);
102        }
103    } while (got);
104  }
105
106  return result;
107}
108