1 // Copyright (C) 2012 The Android Open Source Project
2 // All rights reserved.
3 //
4 // Redistribution and use in source and binary forms, with or without
5 // modification, are permitted provided that the following conditions
6 // are met:
7 // 1. Redistributions of source code must retain the above copyright
8 // notice, this list of conditions and the following disclaimer.
9 // 2. Redistributions in binary form must reproduce the above copyright
10 // notice, this list of conditions and the following disclaimer in the
11 // documentation and/or other materials provided with the distribution.
12 // 3. Neither the name of the project nor the names of its contributors
13 // may be used to endorse or promote products derived from this software
14 // without specific prior written permission.
15 //
16 // THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
17 // ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 // IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 // ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
20 // FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 // DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 // OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 // HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 // LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 // OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 // SUCH DAMAGE.
27
28 #include <cstdlib>
29 #include <exception>
30 #include "cxxabi_defines.h"
31
32 namespace {
33
34 std::terminate_handler current_terminate = __gabixx::__default_terminate;
35 std::unexpected_handler current_unexpected = __gabixx::__default_unexpected;
36
37 } // namespace
38
39
40 namespace __gabixx {
41
42 // The default std::unexpected() implementation will delegate to
43 // std::terminate() so that the user-defined std::terminate() handler can
44 // get the chance to be invoked.
45 //
__default_unexpected(void)46 _GABIXX_NORETURN void __default_unexpected(void) {
47 std::terminate();
48 }
49
50 // The default std::terminate() implementation will crash the process.
51 // This is done to help debugging, i.e.:
52 // - When running the program in a debugger, it's trivial to get
53 // a complete stack trace explaining the failure.
54 //
55 // - Otherwise, the default SIGSEGV handler will generate a stack
56 // trace in the log, that can later be processed with ndk-stack
57 // and other tools.
58 //
59 // - Finally, this also works when a custom SIGSEGV handler has been
60 // installed. E.g. when using Google Breakpad, the termination will
61 // be recorded in a Minidump, which contains a stack trace to be
62 // later analyzed.
63 //
64 // The C++ specification states that the default std::terminate()
65 // handler is library-specific, even though most implementation simply
66 // choose to call abort() in this case.
67 //
__default_terminate(void)68 _GABIXX_NORETURN void __default_terminate(void) {
69 // The crash address is just a "magic" constant that can be used to
70 // identify stack traces (like 0xdeadbaad is used when heap corruption
71 // is detected in the C library). 'cab1' stands for "C++ ABI" :-)
72 *(reinterpret_cast<char*>(0xdeadcab1)) = 0;
73
74 // should not be here, but just in case.
75 abort();
76 }
77
__terminate(std::terminate_handler handler)78 _GABIXX_NORETURN void __terminate(std::terminate_handler handler) {
79 if (!handler)
80 handler = __default_terminate;
81
82 #if _GABIXX_HAS_EXCEPTIONS
83 try {
84 (*handler)();
85 } catch (...) {
86 /* nothing */
87 }
88 #else
89 (*handler)();
90 #endif
91 __default_terminate();
92 }
93
94 } // namespace __gabixx
95
96 namespace std {
97
get_terminate()98 terminate_handler get_terminate() _GABIXX_NOEXCEPT {
99 return __gabixx_sync_load(¤t_terminate);
100 }
101
set_terminate(terminate_handler f)102 terminate_handler set_terminate(terminate_handler f) _GABIXX_NOEXCEPT {
103 if (!f)
104 f = __gabixx::__default_terminate;
105
106 return __gabixx_sync_swap(¤t_terminate, f);
107 }
108
terminate()109 _GABIXX_NORETURN void terminate() _GABIXX_NOEXCEPT_CXX11_ONLY {
110 __gabixx::__terminate(std::get_terminate());
111 }
112
get_unexpected()113 unexpected_handler get_unexpected() _GABIXX_NOEXCEPT {
114 return __gabixx_sync_load(¤t_unexpected);
115 }
116
set_unexpected(unexpected_handler f)117 unexpected_handler set_unexpected(unexpected_handler f) _GABIXX_NOEXCEPT {
118 if (!f)
119 f = __gabixx::__default_terminate;
120
121 return __gabixx_sync_swap(¤t_unexpected, f);
122 }
123
unexpected()124 _GABIXX_NORETURN void unexpected() {
125 unexpected_handler handler = std::get_unexpected();
126 if (handler)
127 (*handler)();
128
129 // If the handler returns, then call terminate().
130 terminate();
131 }
132
133 } // namespace std
134