1 /* $NetBSD: raise_default_signal.c,v 1.3 2008/04/28 20:23:03 martin Exp $ */
2
3 /*-
4 * Copyright (c) 2007 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Luke Mewburn.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32 #if HAVE_NBTOOL_CONFIG_H
33 #include "nbtool_config.h"
34 #endif
35
36 #include <sys/cdefs.h>
37 #if defined(LIBC_SCCS) && !defined(lint)
38 __RCSID("$NetBSD: raise_default_signal.c,v 1.3 2008/04/28 20:23:03 martin Exp $");
39 #endif
40
41 #include <errno.h>
42 #include <signal.h>
43 #include <stdio.h>
44 #include <string.h>
45 #include <util.h>
46
47 #if ! HAVE_RAISE_DEFAULT_SIGNAL
48 /*
49 * raise_default_signal sig
50 * Raise the default signal handler for sig, by
51 * - block all signals
52 * - set the signal handler to SIG_DFL
53 * - raise the signal
54 * - unblock the signal to deliver it
55 *
56 * The original signal mask and signal handler is restored on exit
57 * (whether successful or not).
58 *
59 * Returns 0 on success, or -1 on failure with errno set to
60 * on of the values for sigemptyset(), sigaddset(), sigprocmask(),
61 * sigaction(), or raise().
62 */
63 int
raise_default_signal(int sig)64 raise_default_signal(int sig)
65 {
66 struct sigaction origact, act;
67 sigset_t origmask, fullmask, mask;
68 int retval, oerrno;
69
70 retval = -1;
71
72 /* Setup data structures */
73 /* XXX memset(3) isn't async-safe according to signal(7) */
74 (void)memset(&act, 0, sizeof(act));
75 act.sa_handler = SIG_DFL;
76 act.sa_flags = 0;
77 if ((sigemptyset(&act.sa_mask) == -1) ||
78 (sigfillset(&fullmask) == -1) ||
79 (sigemptyset(&mask) == -1) ||
80 (sigaddset(&mask, sig) == -1))
81 goto restore_none;
82
83 /* Block all signals */
84 if (sigprocmask(SIG_BLOCK, &fullmask, &origmask) == -1)
85 goto restore_none;
86 /* (use 'goto restore_mask' to restore state) */
87
88 /* Enable the SIG_DFL handler */
89 if (sigaction(sig, &act, &origact) == -1)
90 goto restore_mask;
91 /* (use 'goto restore_act' to restore state) */
92
93 /* Raise the signal, and unblock the signal to deliver it */
94 if ((raise(sig) == -1) ||
95 (sigprocmask(SIG_UNBLOCK, &mask, NULL) == -1))
96 goto restore_act;
97
98 /* Flag successful raise() */
99 retval = 0;
100
101 /* Restore the original handler */
102 restore_act:
103 oerrno = errno;
104 (void)sigaction(sig, &origact, NULL);
105 errno = oerrno;
106
107 /* Restore the original mask */
108 restore_mask:
109 oerrno = errno;
110 (void)sigprocmask(SIG_SETMASK, &origmask, NULL);
111 errno = oerrno;
112
113 restore_none:
114 return retval;
115 }
116
117 #endif /* ! HAVE_RAISE_DEFAULT_SIGNAL */
118