1 /* $NetBSD: sigset.c,v 1.2 2008/04/28 20:22:59 martin Exp $ */
2
3 /*-
4 * Copyright (c) 2003 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Klaus Klein.
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 #include <sys/cdefs.h>
33 #if defined(LIBC_SCCS) && !defined(lint)
34 __RCSID("$NetBSD: sigset.c,v 1.2 2008/04/28 20:22:59 martin Exp $");
35 #endif
36
37 #include "namespace.h"
38 #include <errno.h>
39 #include <signal.h>
40 #include <stddef.h>
41
42 sig_t
sigset(int sig,void (* disp)(int))43 sigset(int sig, void (*disp)(int))
44 {
45 sigset_t set, oset;
46 struct sigaction sa, osa;
47
48 osa.sa_handler = SIG_ERR;
49
50 if (disp == SIG_HOLD) {
51 /* Add sig to current signal mask. */
52 if (sigemptyset(&set) != 0)
53 goto out;
54 if (sigaddset(&set, sig) != 0)
55 goto out;
56 if (sigprocmask(SIG_BLOCK, &set, &oset) != 0)
57 goto out;
58
59 if (sigismember(&oset, sig)) {
60 /* Had been masked before, return SIG_HOLD. */
61 osa.sa_handler = SIG_HOLD;
62 } else {
63 /* Return previous disposition. */
64 (void)sigaction(sig, NULL, &osa);
65 }
66 } else if (disp == SIG_ERR) {
67 errno = EINVAL;
68 } else {
69 /* Set up and install new disposition. */
70 sa.sa_handler = disp;
71 if (sigemptyset(&sa.sa_mask) != 0)
72 goto out;
73 sa.sa_flags = 0;
74
75 if (sigaction(sig, &sa, &osa) != 0) {
76 osa.sa_handler = SIG_ERR;
77 goto out;
78 }
79
80 /* Delete sig from current signal mask. */
81 if (sigemptyset(&set) != 0)
82 return (SIG_ERR);
83 if (sigaddset(&set, sig) != 0)
84 return (SIG_ERR);
85 if (sigprocmask(SIG_UNBLOCK, &set, &oset) != 0)
86 return (SIG_ERR);
87
88 /* If had been masked before, return SIG_HOLD. */
89 if (sigismember(&oset, sig))
90 osa.sa_handler = SIG_HOLD;
91 }
92
93 out:
94 return (osa.sa_handler);
95 }
96