1 /*
2  * Copyright (C) 2020 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 #include <stdlib.h>
31 
32 #include <string>
33 
34 extern "C" int __cxa_atexit(void (*func)(void*), void* arg, void* dso);
35 
36 extern void* __dso_handle;
37 
dtor_func(void *)38 static void dtor_func(void*) {}
39 
40 // Prevent the compiler from optimizing out the __cxa_atexit call.
41 void (*volatile g_pdtor_func)(void*) = dtor_func;
42 
main(int argc,char * argv[])43 int main(int argc, char* argv[]) {
44   auto usage = [&argv]() {
45     fprintf(stderr, "usage: %s COUNT MODE\n", argv[0]);
46     fprintf(stderr, "MODE is one of '_Exit' or 'exit'.\n");
47     exit(1);
48   };
49 
50   if (argc != 3) usage();
51 
52   int count = atoi(argv[1]);
53 
54   // Two modes: "_Exit" ==> exit early w/o calling dtors, "exit" ==> call dtors on exit.
55   std::string mode = argv[2];
56   if (mode != "_Exit" && mode != "exit") usage();
57 
58   for (int i = 0; i < count; ++i) {
59     __cxa_atexit(g_pdtor_func, nullptr, &__dso_handle);
60   }
61 
62   if (mode == "_Exit") {
63     _Exit(0);
64   } else {
65     exit(0);
66   }
67 }
68