1/* $NetBSD: h_atexit.c,v 1.1 2011/01/12 19:44:08 pgoyette Exp $ */
2
3/*-
4 * Copyright (c) 2011 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code was contributed to The NetBSD Foundation by Jason R. Thorpe.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 *    notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 *    notice, this list of conditions and the following disclaimer in the
16 *    documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
19 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
20 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
21 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
22 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
23 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
24 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
25 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
26 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
27 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
28 * POSSIBILITY OF SUCH DAMAGE.
29 */
30
31#include <sys/cdefs.h>
32__COPYRIGHT("@(#) Copyright (c) 2011\
33 The NetBSD Foundation, inc. All rights reserved.");
34__RCSID("$NetBSD: h_atexit.c,v 1.1 2011/01/12 19:44:08 pgoyette Exp $");
35
36#include <stdio.h>
37#include <stdlib.h>
38#include <signal.h>
39#include <string.h>
40#include <unistd.h>
41
42extern int __cxa_atexit(void (*func)(void *), void *, void *);
43extern void __cxa_finalize(void *);
44
45#ifdef __FreeBSD__
46/*
47 * On shared object unload, in __cxa_finalize, call and clear all installed
48 * atexit and __cxa_atexit handlers that are either installed by unloaded
49 * dso, or points to the functions provided by the dso.
50 *
51 * The reason of the change is to ensure that there is no lingering pointers
52 * to the unloaded code after the dlclose(3).  It is known reason for infinite
53 * stream of the crash reports for many programs which use loadable modules
54 * and fail to properly clean on module unload.  Examples are apache, php,
55 * perl etc.
56 *
57 * You pass the &dso_handle_1 and &dso_handle_2, which points inside the
58 * main binary, to the registration function.  The code from r211706,
59 * correctly detects that they are for the main binary, and on the first
60 * call to __cxa_finalize(), which also pass pointer to main binary, all
61 * registered functions from the main binary are executed.
62 */
63
64static void *dso_handle_1 = (void *)1;
65static void *dso_handle_2 = (void *)2;
66static void *dso_handle_3 = (void *)3;
67#else
68static int dso_handle_1;
69static int dso_handle_2;
70static int dso_handle_3;
71#endif
72
73static int arg_1;
74static int arg_2;
75static int arg_3;
76
77static int exiting_state;
78
79#define	ASSERT(expr)							\
80do {									\
81	if ((expr) == 0) {						\
82		write(STDERR_FILENO, __func__, strlen(__func__));	\
83		write(STDERR_FILENO, ": ", 2);				\
84		write(STDERR_FILENO, __STRING(expr),			\
85		      strlen(__STRING(expr)));				\
86		write(STDERR_FILENO, "\n", 1);				\
87		my_abort();						\
88	}								\
89} while (/*CONSTCOND*/0)
90
91#define	SUCCESS()							\
92do {									\
93	write(STDOUT_FILENO, __func__, strlen(__func__));		\
94	write(STDOUT_FILENO, "\n", 1);					\
95} while (/*CONSTCOND*/0)
96
97static void
98my_abort(void)
99{
100
101	kill(getpid(), SIGABRT);
102	/* NOTREACHED */
103}
104
105static void
106cxa_handler_5(void *arg)
107{
108	static int cxa_handler_5_called;
109
110	ASSERT(arg == (void *)&arg_1);
111	ASSERT(cxa_handler_5_called == 0);
112	ASSERT(exiting_state == 5);
113
114	exiting_state--;
115	cxa_handler_5_called = 1;
116	SUCCESS();
117}
118
119static void
120cxa_handler_4(void *arg)
121{
122	static int cxa_handler_4_called;
123
124	ASSERT(arg == (void *)&arg_1);
125	ASSERT(cxa_handler_4_called == 0);
126	ASSERT(exiting_state == 4);
127
128	exiting_state--;
129	cxa_handler_4_called = 1;
130	SUCCESS();
131}
132
133static void
134cxa_handler_3(void *arg)
135{
136	static int cxa_handler_3_called;
137
138	ASSERT(arg == (void *)&arg_2);
139	ASSERT(cxa_handler_3_called == 0);
140	ASSERT(exiting_state == 3);
141
142	exiting_state--;
143	cxa_handler_3_called = 1;
144	SUCCESS();
145}
146
147static void
148cxa_handler_2(void *arg)
149{
150	static int cxa_handler_2_called;
151
152	ASSERT(arg == (void *)&arg_3);
153	ASSERT(cxa_handler_2_called == 0);
154	ASSERT(exiting_state == 2);
155
156	exiting_state--;
157	cxa_handler_2_called = 1;
158	SUCCESS();
159}
160
161static void
162normal_handler_1(void)
163{
164	static int normal_handler_1_called;
165
166	ASSERT(normal_handler_1_called == 0);
167	ASSERT(exiting_state == 1);
168
169	exiting_state--;
170	normal_handler_1_called = 1;
171	SUCCESS();
172}
173
174static void
175normal_handler_0(void)
176{
177	static int normal_handler_0_called;
178
179	ASSERT(normal_handler_0_called == 0);
180	ASSERT(exiting_state == 0);
181
182	normal_handler_0_called = 1;
183	SUCCESS();
184}
185
186int
187main(int argc, char *argv[])
188{
189
190	exiting_state = 5;
191
192	ASSERT(0 == atexit(normal_handler_0));
193	ASSERT(0 == atexit(normal_handler_1));
194#ifdef __FreeBSD__
195	ASSERT(0 == __cxa_atexit(cxa_handler_4, &arg_1, dso_handle_1));
196	ASSERT(0 == __cxa_atexit(cxa_handler_5, &arg_1, dso_handle_1));
197	ASSERT(0 == __cxa_atexit(cxa_handler_3, &arg_2, dso_handle_2));
198	ASSERT(0 == __cxa_atexit(cxa_handler_2, &arg_3, dso_handle_3));
199
200	__cxa_finalize(dso_handle_1);
201	__cxa_finalize(dso_handle_2);
202#else
203	ASSERT(0 == __cxa_atexit(cxa_handler_4, &arg_1, &dso_handle_1));
204	ASSERT(0 == __cxa_atexit(cxa_handler_5, &arg_1, &dso_handle_1));
205	ASSERT(0 == __cxa_atexit(cxa_handler_3, &arg_2, &dso_handle_2));
206	ASSERT(0 == __cxa_atexit(cxa_handler_2, &arg_3, &dso_handle_3));
207
208	__cxa_finalize(&dso_handle_1);
209	__cxa_finalize(&dso_handle_2);
210#endif
211	exit(0);
212}
213