1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 1997 - 1999, 2001 Brian Somers <brian@Awfulhak.org>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 *
28 * $FreeBSD$
29 */
30
31#include <sys/types.h>
32
33#include <signal.h>
34
35#include "log.h"
36#include "sig.h"
37
38static int caused[NSIG];	/* An array of pending signals */
39static int necessary;		/* Anything set ? */
40static sig_type handler[NSIG];	/* all start at SIG_DFL */
41
42
43/*
44 * Record a signal in the "caused" array
45 *
46 * This function is the only thing actually called in signal context.  It
47 * records that a signal has been caused and that sig_Handle() should be
48 * called (in non-signal context) as soon as possible to process that
49 * signal.
50 */
51static void
52signal_recorder(int sig)
53{
54  caused[sig - 1]++;
55  necessary = 1;
56}
57
58
59/*
60 * Set up signal_recorder to handle the given sig and record ``fn'' as
61 * the function to ultimately call in sig_Handle().  ``fn'' will not be
62 * called in signal context (as sig_Handle() is not called in signal
63 * context).
64 */
65sig_type
66sig_signal(int sig, sig_type fn)
67{
68  sig_type Result;
69
70  if (sig <= 0 || sig > NSIG) {
71    /* Oops - we must be a bit out of date (too many sigs ?) */
72    log_Printf(LogALERT, "Eeek! %s:%d: I must be out of date!\n",
73	      __FILE__, __LINE__);
74    return signal(sig, fn);
75  }
76  Result = handler[sig - 1];
77  if (fn == SIG_DFL || fn == SIG_IGN) {
78    signal(sig, fn);
79    handler[sig - 1] = (sig_type) 0;
80  } else {
81    handler[sig - 1] = fn;
82    signal(sig, signal_recorder);
83  }
84  caused[sig - 1] = 0;
85  return Result;
86}
87
88
89/*
90 * Call the handlers for any pending signals
91 *
92 * This function is called from a non-signal context - in fact, it's
93 * called every time select() in DoLoop() returns - just in case
94 * select() returned due to a signal being recorded by signal_recorder().
95 */
96int
97sig_Handle()
98{
99  int sig;
100  int got;
101  int result;
102
103  result = 0;
104  if (necessary) {
105    /* We've *probably* got something in `caused' set */
106    necessary = 0;
107    /* `necessary' might go back to 1 while we're in here.... */
108    do {
109      got = 0;
110      for (sig = 0; sig < NSIG; sig++)
111        if (caused[sig]) {
112	  caused[sig]--;
113	  got++;
114	  result++;
115	  (*handler[sig])(sig + 1);
116        }
117    } while (got);
118  }
119
120  return result;
121}
122