1/*-
2 * Copyright (c) 2003 David Xu <davidxu@freebsd.org>
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 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27#include <sys/cdefs.h>
28__FBSDID("$FreeBSD$");
29
30#include "namespace.h"
31#include <errno.h>
32#include <signal.h>
33#include "un-namespace.h"
34#include "thr_private.h"
35
36int	_sigaltstack(stack_t *_ss, stack_t *_oss);
37
38__weak_reference(_sigaltstack, sigaltstack);
39
40int
41_sigaltstack(stack_t *_ss, stack_t *_oss)
42{
43	struct pthread *curthread = _get_curthread();
44	stack_t ss, oss;
45	int oonstack, errsave, ret;
46	kse_critical_t crit;
47
48	if (curthread->attr.flags & PTHREAD_SCOPE_SYSTEM) {
49		crit = _kse_critical_enter();
50		ret = __sys_sigaltstack(_ss, _oss);
51		errsave = errno;
52		/* Get a copy */
53		if (ret == 0 && _ss != NULL)
54			curthread->sigstk = *_ss;
55		_kse_critical_leave(crit);
56		errno = errsave;
57		return (ret);
58	}
59
60	if (_ss)
61		ss = *_ss;
62	if (_oss)
63		oss = *_oss;
64
65	/* Should get and set stack in atomic way */
66	crit = _kse_critical_enter();
67	oonstack = _thr_sigonstack(&ss);
68	if (_oss != NULL) {
69		oss = curthread->sigstk;
70		oss.ss_flags = (curthread->sigstk.ss_flags & SS_DISABLE)
71		    ? SS_DISABLE : ((oonstack) ? SS_ONSTACK : 0);
72	}
73
74	if (_ss != NULL) {
75		if (oonstack) {
76			_kse_critical_leave(crit);
77			errno = EPERM;
78			return (-1);
79		}
80		if ((ss.ss_flags & ~SS_DISABLE) != 0) {
81			_kse_critical_leave(crit);
82			errno = EINVAL;
83			return (-1);
84		}
85		if (!(ss.ss_flags & SS_DISABLE)) {
86			if (ss.ss_size < MINSIGSTKSZ) {
87				_kse_critical_leave(crit);
88				errno = ENOMEM;
89				return (-1);
90			}
91			curthread->sigstk = ss;
92		} else {
93			curthread->sigstk.ss_flags |= SS_DISABLE;
94		}
95	}
96	_kse_critical_leave(crit);
97	if (_oss != NULL)
98		*_oss = oss;
99	return (0);
100}
101
102int
103_thr_sigonstack(void *sp)
104{
105	struct pthread *curthread = _get_curthread();
106
107	return ((curthread->sigstk.ss_flags & SS_DISABLE) == 0 ?
108	    (((size_t)sp - (size_t)curthread->sigstk.ss_sp) < curthread->sigstk.ss_size)
109	    : 0);
110}
111
112