1/*
2 * Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>
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 * 3. Neither the name of the author nor the names of any co-contributors
14 *    may be used to endorse or promote products derived from this software
15 *    without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * $FreeBSD$
30 */
31
32#include "namespace.h"
33#include <signal.h>
34#include <errno.h>
35#include <pthread.h>
36#include "un-namespace.h"
37#include "thr_private.h"
38
39__weak_reference(_sigaction, sigaction);
40
41int
42_sigaction(int sig, const struct sigaction * act, struct sigaction * oact)
43{
44	int ret = 0;
45	int err = 0;
46	struct sigaction newact, oldact;
47	struct pthread *curthread;
48	kse_critical_t crit;
49
50	/* Check if the signal number is out of range: */
51	if (sig < 1 || sig > _SIG_MAXSIG) {
52		/* Return an invalid argument: */
53		errno = EINVAL;
54		ret = -1;
55	} else {
56		if (act)
57			newact = *act;
58
59		crit = _kse_critical_enter();
60		curthread = _get_curthread();
61		KSE_LOCK_ACQUIRE(curthread->kse, &_thread_signal_lock);
62
63		oldact = _thread_sigact[sig - 1];
64
65		/* Check if a signal action was supplied: */
66		if (act != NULL) {
67			/* Set the new signal handler: */
68			_thread_sigact[sig - 1] = newact;
69		}
70
71		/*
72		 * Check if the kernel needs to be advised of a change
73		 * in signal action:
74		 */
75		if (act != NULL) {
76
77			newact.sa_flags |= SA_SIGINFO;
78
79			/*
80			 * Check if the signal handler is being set to
81			 * the default or ignore handlers:
82			 */
83			if (newact.sa_handler != SIG_DFL &&
84			    newact.sa_handler != SIG_IGN) {
85				/*
86				 * Specify the thread kernel signal
87				 * handler:
88				 */
89				newact.sa_sigaction = _thr_sig_handler;
90			}
91			/*
92			 * Install libpthread signal handler wrapper
93			 * for SIGINFO signal if threads dump enabled
94			 * even if a user set the signal handler to
95			 * SIG_DFL or SIG_IGN.
96			 */
97			if (sig == SIGINFO && _thr_dump_enabled()) {
98				newact.sa_sigaction = _thr_sig_handler;
99			}
100			/* Change the signal action in the kernel: */
101			if (__sys_sigaction(sig, &newact, NULL) != 0) {
102				_thread_sigact[sig - 1] = oldact;
103				/* errno is in kse, will copy it to thread */
104				err = errno;
105				ret = -1;
106			}
107		}
108		KSE_LOCK_RELEASE(curthread->kse, &_thread_signal_lock);
109		_kse_critical_leave(crit);
110		/*
111		 * Check if the existing signal action structure contents are
112		 * to be returned:
113		*/
114		if (oact != NULL) {
115			/* Return the existing signal action contents: */
116			*oact = oldact;
117		}
118		if (ret != 0) {
119			/* Return errno to thread */
120			errno = err;
121		}
122	}
123
124	/* Return the completion status: */
125	return (ret);
126}
127