libdlclosetest1.cpp revision 83b47ccbc4066ef19f5d95261d8a892567a7f0a7 
1/*
2 * Copyright (C) 2008 The Android Open Source Project
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 *  * Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 *  * Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in
12 *    the documentation and/or other materials provided with the
13 *    distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29#include <stdio.h>
30
31class Foo {
32public:
33    Foo();
34    virtual ~Foo();
35};
36
37
38/* This library is used to ensure that static C++ construction
39 * and destruction operate normally on dlopen() and dlclose().
40 *
41 * We use a global variable inside the DLL called "x"
42 * and initialize it to 1 in the static C++ constructor.
43 *
44 * The main program can access its address through dlsym()
45 * then later check that it was properly initialized.
46 */
47extern "C" int  x;
48int x = 0;
49
50Foo::Foo()
51{
52    x = 1;
53    fprintf(stderr, "%s: setting x to 1\n", __FUNCTION__);
54}
55
56/* Similarly, the main program can provide the address of
57 * an integer, named "y", that will be set to 2 when the
58 * static C++ destructor is called on dlclose().
59 *
60 * This address must be provided through the "set_y" function
61 * that can also be resolved through dlsym() by the program.
62 */
63static int *to_y = NULL;
64
65Foo::~Foo()
66{
67    if (to_y == NULL) {
68        fprintf(stderr, "%s: to_y uinitialized !!\n", __FUNCTION__);
69        *(int *)NULL = 0; // crash
70    }
71    *to_y = 2;
72    fprintf(stderr, "%s: setting y(%p) to 2 !\n", __FUNCTION__, to_y);
73}
74
75static Foo  f;
76
77extern "C"
78void set_y(int *y)
79{
80    to_y = y;
81    fprintf(stderr, "%s: setting to_y=%p\n", __FUNCTION__, y);
82}
83