1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
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
29 #include <sys/types.h>
30
31 #include <signal.h>
32
33 #include "log.h"
34 #include "sig.h"
35
36 static int caused[NSIG]; /* An array of pending signals */
37 static int necessary; /* Anything set ? */
38 static 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 */
49 static void
signal_recorder(int sig)50 signal_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 */
63 sig_type
sig_signal(int sig,sig_type fn)64 sig_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 */
94 int
sig_Handle(void)95 sig_Handle(void)
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