1/*-
2 * Copyright (c) 1997 - 1999, 2001 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 * $FreeBSD$
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/*
42 * Record a signal in the "caused" array
43 *
44 * This function is the only thing actually called in signal context.  It
45 * records that a signal has been caused and that sig_Handle() should be
46 * called (in non-signal context) as soon as possible to process that
47 * signal.
48 */
49static void
50signal_recorder(int sig)
51{
52  caused[sig - 1]++;
53  necessary = 1;
54}
55
56
57/*
58 * Set up signal_recorder to handle the given sig and record ``fn'' as
59 * the function to ultimately call in sig_Handle().  ``fn'' will not be
60 * called in signal context (as sig_Handle() is not called in signal
61 * context).
62 */
63sig_type
64sig_signal(int sig, sig_type fn)
65{
66  sig_type Result;
67
68  if (sig <= 0 || sig > NSIG) {
69    /* Oops - we must be a bit out of date (too many sigs ?) */
70    log_Printf(LogALERT, "Eeek! %s:%d: I must be out of date!\n",
71	      __FILE__, __LINE__);
72    return signal(sig, fn);
73  }
74  Result = handler[sig - 1];
75  if (fn == SIG_DFL || fn == SIG_IGN) {
76    signal(sig, fn);
77    handler[sig - 1] = (sig_type) 0;
78  } else {
79    handler[sig - 1] = fn;
80    signal(sig, signal_recorder);
81  }
82  caused[sig - 1] = 0;
83  return Result;
84}
85
86
87/*
88 * Call the handlers for any pending signals
89 *
90 * This function is called from a non-signal context - in fact, it's
91 * called every time select() in DoLoop() returns - just in case
92 * select() returned due to a signal being recorded by signal_recorder().
93 */
94int
95sig_Handle()
96{
97  int sig;
98  int got;
99  int result;
100
101  result = 0;
102  if (necessary) {
103    /* We've *probably* got something in `caused' set */
104    necessary = 0;
105    /* `necessary' might go back to 1 while we're in here.... */
106    do {
107      got = 0;
108      for (sig = 0; sig < NSIG; sig++)
109        if (caused[sig]) {
110	  caused[sig]--;
111	  got++;
112	  result++;
113	  (*handler[sig])(sig + 1);
114        }
115    } while (got);
116  }
117
118  return result;
119}
120